Fermilab, Batavia
Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-76CH03000
Steady growth of luminosity has been demonstrated during the entire Tevatron Run II culminating in a record Tevatron performance. During last two years the major contributions came from improvements in antiproton stacking and cooling as well as from numerous improvements in the Tevatron. The talk will describe these improvements as well as other unexpected problems which were encountered and resolved on the road to this success.
Edinburgh University, Edinburgh
TRIUMF, Vancouver
Since the 1980s the nuclear physics community has pursued the development of intense and exotic radioactive ion beams for many areas of study including astrophysics. The myriad of radionuclides that exist fleetingly inside explosive stellar scenarios are involved in nuclear reactions which are extremely difficult to model from theory, and in these cases experimental data is crucial. The measurement problems of astrophysics often require not only the most sensitive detectors and most intense radioactive beams, but also the right combination of experimental facilities, accelerators and detectors. The community has tackled these problems in a variety of different ways, with many labs already active or coming online with new aggressive accelerator, isotope production and measurement technology ready to target the big astrophysics questions. This talk gives an overview of some experimental methods and facilities used to derive astrophysically-relevant nuclear properties and highlights the places in the world that perform these studies.
J-PARC, KEK & JAEA, Ibaraki-ken
The Japan Proton Accelerator Research Complex (J-PARC) is a multi-purpose facility making full use of secondary particles like neutrons, muons, Kaons, and neutrinos produced by the MW-class proton accelerators. The J-PARC accelerator scheme inserts a 3-GeV Rapid-Cycling Synchrotron (RCS) in between a 400-MeV injector linac (at present 181 MeV) and a several-ten GeV Main Ring (MR). The RCS has already demonstrated extraction of one pulse of 2.6·1013 protons at 3 GeV, which corresponds to 315 kW if operated at 25 Hz, with a beam loss less than one percent, and a beam power of 210 kW for a period of 70 sec in September. The beam circulation and RF capture in MR have been done in May. Also, the neutron production target was beam-commissioned, providing high-resolution, high-efficiency neutrons. The RCS users’ run and the 30-GeV MR acceleration are planned in December. Rationale for the J-PARC accelerator scheme will be resumed on the basis of the results and difficulties encountered during the development, the construction and the commissioning. The upgrade plan, and, hopefully, some experimental results will be presented.
INFN/LNL, Legnaro (PD)
The speaker will have expertise in the design, construction and operation of RFQs, both normal and superconducting. This talk will focus mostly on recent developments in RFQs for high power proton and deuteron beams, for both scientific and diverse purposes (e.g. Radioactive Nuclear Beam facilities, long-term irradiation tests of materials for Thermonuclear Fusion Reactors). The experience of the group at LNL in the field of cw RFQs originates from the realization of the PIAVE RFQ (superconducting 585 keV/u, heavy ion A/q<8.5) and the construction of the TRASCO RFQ (5 MeV, 30 mA protons). More recently within the collaboration between Europe and Japan for the construction of IFMIF-EVEDA in Rokkasho, the group at LNL is in charge of the design and construction of the RFQ (130 mA deuteron, 5 MeV). The physics design and the first construction test results will be ready for the PAC conference in 2009. In the same talk, the design approaches and experimental results of cw RFQs under development (for lower beam power) by other groups in Europe could be reviewed.
Fermilab, Batavia
Funding: Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
We present the strategy which has been used recently to optimize integrated luminosity at the Fermilab Tevatron proton-antiproton collider. We use a relatively simple model where we keep the proton intensity fixed, use parameters from fits to the luminosity decay of recent stores as a function of initial antiproton intensity (stash size), and vary the stash size to optimize the integrated luminosity per week. The model assumes a fixed rate of antiproton production, that a store is terminated as soon as the target stash size for the next store is reached, and that the only downtime is due to store turn-around time. An optimal range of stash size is predicted. Since the start of Tevatron operations based on this procedure we have seen an improvement of approximately 35% in integrated luminosity. Other recent operational improvements have been achieved by decreasing the shot setup time and by reducing beam-beam effects by making the proton and antiproton brightnesses more compatible , for example by scraping protons to smaller emittances.
BNL, Upton, Long Island, New York
Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
After having provided collisions of polarized protons at a beam energy of 100 GeV since 2001, the Relativistic Heavy Ion Collider~(RHIC) at BNL reached its design energy of polarized proton collision at 250 GeV. With the help of the two full Siberian snakes in each ring as well as careful orbit correction and working point control, polarization was preserved during acceleration from injection to 250~GeV. During the course of the Physics data taking, the spin rotators on either side of the experiments of STAR and PHENIX were set up to provide collisions with longitudinal polarization at both experiments. Various techniques to increase luminosity like further beta star squeeze and RF system upgrades as well as gymnastics to shorten the bunch length at store were also explored during the run. This paper reports the performance of the run as well as the plan for future performance improvement in RHIC.
BNL, Upton, Long Island, New York
CERN, Geneva
Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy and the US LHC Accelerator Research Program (LARP).
In the Relativistic Heavy Ion Collider (RHIC) beams collide in the two interaction points IP6 and IP8. An increase of the bunch intensity above 2·1011 in polarized proton operation appears difficult due to the large beam-beam tune spread generated by the two collisions. A low energy electron beam or electron lens has been proposed to mitigate the head on beam-beam effect. In RHIC such a device could be located near IP10. We summarize multi-particle weak-strong beam-beam simulations of head-on beam-beam compensation with an electron lens. The proton beam's lifetime and emittance are calculated and compared for situations with and without an electron lens. Parameters such as the proton bunch intensity, the electron beam intensity and the betatron phase advances between IP8 and IP10 are scanned in the simulations.
BNL, Upton, Long Island, New York
Hundred megawatt level fast ramping power converters to drive proton and heavy ion machines are under research and development at accelerator facilities in the world. This is a leading edge technology. There are several topologies to achieve this power level. Their advantages and related issues will be discussed.
OXFORDphysics, Oxford, Oxon
JAI, Oxford
Funding: This work was supported by EPSRC grant EP/E032869/1.
PAMELA is a design study of a non-scaling FFAG for hadron therapy aiming to deliver 250 MeV protons and 400 MeV/u carbon ions. This paper outlines the general magnet design required for the 250 MeV proton case. The magnet design is challenging because of the combination of required field strength (up to 4T), geometric constraints (the magnets need to be short) and large beam aperture (up to 160 mm). All magnets are combined function magnets with dipole, quadrupole, sextupole and octupole field components of good field quality.
KEK, Ibaraki
The titanium nitride (TiN) coating inside a beam duct has been recently attracting attention as a measure to mitigate the electron cloud effect in positron/proton rings. Here studied is the gas desorption from the TiN-coated copper beam duct, which will be adopted in the upgrade of KEK B-factory (KEKB). In the experiment, the pressure in a TiN-coated duct was measured and compared with that in a non-coated one. The TiN film (200 nm thick) was coated by DC magnetron sputtering at KEK. After an air exposure for the previously-determined period, the duct was evacuated by a turbo-molecular pump (300 l/s). At 50 hours after evacuation, the pressure was about 4 times larger than that for the case of the non-coated one. The residual gas was mainly water. In order to fine the minimum baking temperature to decrease the gas desorption from the TiN coating, the pressures were measured after the baking by changing the temperatures in the practical range, from 50 to 150 degrees. The pressure after the baking at 80 degrees was finally found to be comparable to that for the non-coated one. This paper describes these results in detail including the measurements of gas desorption rates.
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
Since the start of the beam commissioning on October 2007, we have succeeded to increase the beam power of the Rapid Cycling Synchrotron (RCS) in the Japan Proton Accelerator Research Complex (J-PARC). The effect of the high power beam on the vacuum had become visible above the beam power of 50 kW. When the high power beam was operated at 25 Hz, the vacuum pressure became higher. Especially the vacuum of the injection area became worse than other areas. The residual gas analyzer was installed in order to investigate which kinds of outgassing were desorbed by the high power beam. The carbon compound mainly increased with the high power beam in the area. The source of the ougtassing is thought to be carbon foils for charge exchange and/or a electron catcher which was installed in order to collect the stripped electron by the carbon foil. After this, the RCS forwards into the stage where the high power beam is continuously operated during a few weeks. We will report the results of the conditioning effect on the vacuum by the beam itself.
Imperial College of Science and Technology, Department of Physics, London
JAI, Oxford
OXFORDphysics, Oxford, Oxon
For PAMELA project, the injection lay out for both protons as well as carbon 6+ ions is discussed. Injection system would consist of a 30 MeV cyclotron for protons and a chain of elements for carbon ions such as ECR ion source, bending magnets and focusing solenoids; RFQ, IH/CH structures and a striping foils. The charge particle simulation for different protons as well as carbon ions passing through the elements has been carried out with General Particle Tracer (GPT), software.
Muons, Inc, Batavia
UMD, College Park, Maryland
ORNL, Oak Ridge, Tennessee
Funding: Supported in part by the US DOE Contract DE-AC05-00OR22725
Spallation neutron source user facilities require reliable, intense beams of protons. The technique of H- charge exchange injection into a storage ring or synchrotron can provide the needed beam currents, but may be limited by the ion sources that have currents and reliability that do not meet future requirements and emittances that are too large for efficient acceleration. In this project we are developing an H- source which will synthesize the most important developments in the field of negative ion sources to provide high current, small emittance, good lifetime, high reliability, and power efficiency. We describe planned modifications to the present external antenna source at SNS that involve: 1) replacing the present 2 MHz plasma-forming solenoid antenna with a 60 MHz saddle-type antenna and 2) replacing the permanent multicusp magnet with a weaker electro-magnet, in order to increase the plasma density near the outlet aperture. The SNS test stand will then be used to verify simulations of this approach that indicate significant improvements in H- output current and efficiency, where lower RF power will allow higher duty factor, longer source lifetime, and/or better reliability.
Muons, Inc, Batavia
Fermilab, Batavia
The study of rare processes using a beam of muons that stop in a target provides access to new physics at and beyond the reach of energy frontier colliders. The flux of stopping muons is limited by the pion production process and by stochastic processes in the material used to slow down the decay muons. Innovative muon beam collection and cooling techniques are applied to the design of stopping muon beams in order to provide better beams for such experiments. Such intense stopping beams will also support the development of applications such as muon spin resonance and muon-catalyzed fusion.
Fermilab, Batavia
Extensive work has been done to create an accurate model of beam dynamics at the Fermilab Tevatron. This talk will present validation and results from the development of a simulation of the machine including multiple beam dynamics effects. The essential features of the simulation include a fully 3D strong-strong beam-beam particle-in-cell Poisson solver, interactions among multiple bunches and both head-on and long-range beam-beam collisions, coupled linear optics and helical trajectory consistent with beam orbit measurements, chromaticity and resistive wall impedance. The individual physical processes are validated against measured data where possible, and analytic calculations elsewhere. The simulation result discussion will focus on the effects of increasing beam intensity with single and multiple bunches on the impedance of the beams.
IPN, Orsay
INFN/LASA, Segrate (MI)
SCK-CEN, Mol
CEA, Gif-sur-Yvette
IAP, Frankfurt am Main
An Accelerator Driven System (ADS) for transmutation of nuclear waste typically requires a 600 MeV - 1 GeV accelerator delivering a proton flux of a few mA for demonstrators, and a few tens of mA for large industrial systems. Such a machine belongs to the category of the high-power proton accelerators, with an additional requirement for exceptional "reliability": because of the induced thermal stress to the subcritical core, the number of unwanted "beam-trips" should not exceed a few per year, a specification that is far above usual performance. This paper describes the reference solution adopted for such a machine, based on a so-called "fault-tolerant" linear superconducting accelerator, and presents the status of the associated R&D. This work is performed within the 6th Framework Program EC project "EUROTRANS".
ANL, Argonne
GANIL, Caen
Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.
We have developed and tested an X-ray based Bunch Length Detector (XBLD) for application in ion accelerators. X-rays produced as a result of ion beam interactions with matter are used to generate photoelectrons. The photoelectrons are analyzed by an rf deflector synchronized with the master oscillator, similar to the BLDs based on secondary electrons. The expected time resolution is several picoseconds. The proposed XBLD is particularly useful for the measurement of cw heavy-ion beams passing through a stripper foil or film in a high-power driver accelerator. The results of the XBLD commissioning and beam bunch profile measurements at the ANL heavy-ion cw ATLAS accelerator will be presented.
KEK, Ibaraki
KEK/JAEA, Ibaraki-Ken
J-PARC is a unique accelerator, because magnetic alloy (MA) loaded cavities are employed for the first time in the rf systems of high intensity proton synchrotrons. High field gradients of more than 20 kV/m are achieved covering the frequency range from 0.9 MHz to 3.4 MHz. The peak voltage of 45 kV per cavity is obtained by driving with two 600 kW tetrodes in push-pull. The first high intensity beam acceleration was successfully initiated at J-PARC RCS. Although RCS beam commissioning started with 10 rf systems, instead of 11 as designed, RCS succeeded in the acceleration of an intense proton beam, which is equivalent to 300 kW when operated at 25 Hz. The longitudinal painting based on the simulation with superimposed second harmonics and with phase and momentum manipulations was the key of success. In December 2008, the J-PARC MR beam is scheduled for its first acceleration up to 30 GeV, and the Material and Life Science facilities start the user operations. During the development stage of the MA cavities, some serious problems such as electrical breakdown on core surfaces occurred. The problems were solved in a short term, and all rf systems were completed on schedule.
ORNL, Oak Ridge, Tennessee
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
Paul Scherrer Institute, Spallation Source Division, ASQ, Villigen PSI
There are three spallation neutron source facilities in the world with the potential of operating in the one megawatt proton beam power range. The SINQ facility at the Paul Scherrer Institut has already operated in this power range for several years with various water-cooled solid targets, and used a liquid metal (lead-bismuth) target for a period of four months in conducting its successful MEGAPIE project in 2006. The Spallation Neutron Source (SNS) facility at Oak Ridge National Laboratory began operation in 2006 and is approaching the one megawatt level using a liquid mercury target. The Japan Proton Accelerator Research Complex (J-PARC), which also has a mercury target, began beam-on-target operations in 2008 and is on its way to ramping-up its power level to one megawatt over the next few years. This paper will summarize the operating experience and planned improvements for the spallation targets at these megawatt class facilities.
PU, Princeton, New Jersey
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
STFC/RAL, Chilton, Didcot, Oxon
ORNL, Oak Ridge, Tennessee
CERN, Geneva
BNL, Upton, Long Island, New York
Fermilab, Batavia
The MERIT (MERcury Intense Target) experiment was run in the fall of 2007 using 14 and 24 GeV intense proton beams from the CERN PS. It is a proof-of-principle experiment designed to validate a target concept for producing an intense muon source for a future muon collider or neutrino factory. The experiment successfully demonstrated a target technique for multi-MW proton beams that utilizes a free-flowing liquid metal jet within the confines of a high-field solenoid. We describe the experimental strategy and parameters, as well as the results obtained and their implications for future muon-based accelerator facilities.
Far-Tech, Inc., San Diego, California
We describe a novel acceleration structure for acceleration of electron and ion beams where the cell-to-cell coupling is provided by slot resonances in the wall of adjacent accelerator cells. As with the side-coupled linac, the concept allows for the operation of a standing-wave structure in a phase and amplitude stabilized pi/2 mode. We explore the applications of such a structure to electron and ion accelerators.
Far-Tech, Inc., San Diego, California
The fixed-field alternate gradient (FFAG) synchrotron offers an attractive solution for systems that require rapid acceleration over a wide range of energies. The ability to rapidly tune the frequency of the accelerating cavity in the “non-scaling” variety of an FFAG synchrotron represents a fundamental barrier to their implementation in a wide variety of applications for proton, ion and muon acceleration. Initial results of the rapidly tunable cavity design for specific application to proton and light ion medical FFAG accelerators are presented.
Muons, Inc, Batavia
Fermilab, Batavia
Funding: Supported by STTR Grant DE-FG02-07ER86320 and FRA DOE contract number DE-AC02-07CH11359
Originally conceived as a solution for FFAG applications, a new compact RF cavity design that tunes rapidly over various frequency ranges can be used to upgrade existing machines. The design being developed uses orthogonally biased garnet cores for fast frequency tuning and liquid dielectric to adjust the frequency range and to control the core temperature. We describe measurements of candidate ferrite and dielectric materials. The first use of the new cavity concept will be for improvements to the 8 GeV Fermilab Booster synchrotron.
Fermilab, Batavia
Muons, Inc, Batavia
Voss Scientific, Albuquerque, New Mexico
Funding: Supported in part by USDOE STTR Grant DE-FG02-08ER86350 and and FRA DOE contract number DE-AC02-07CH11359
RF cavities pressurized with hydrogen gas may provide effective muon beam ionization cooling needed for muon colliders. Recent 805 MHz test cell studies reported below include the first use of SF6 dopant to reduce the effects of the electrons that will be produced by the ionization cooling process in hydrogen or helium. Measurements of maximum gradient in the Paschen region are compared to a simulation model for a 0.01% SF6 doping of hydrogen. The observed good agreement of the model with the measurements is a prerequisite to the investigation of other dopants.
FZJ, Jülich
CERN, Geneva
The COoler SYnchrotron COSY at the Forschungszentrum Jülich is operating now since 1992. Up to 5*1010 protons can be delivered over a momentum range of 600 MeV/c to 3.6 GeV/c. The prototype of the HESR barrier bucket cavity was installed into COSY and many measurements have been performed. Especially the co-operation of barrier bucket with stochastic cooling has been studied. During the measurements the internal WASA Pellet target was available which is similar to the PANDA target at the HESR. A 1.2m long cryo-tank has been designed and installed to measure the sensitivities of new pickup structures for the HESR stochastic cooling system. Tank design and structures arrangement correspond to the projected HESR stochastic cooling layout. The recent results will be presented.
KEK, Ibaraki
CEA, Gif-sur-Yvette
LPSC, Grenoble
This paper presents the RF systems of RACCAM FFAG for medical applications. Design of the RF system was updated to fit short and curved straight section of the spiral FFAG in view of preserving the compactness of the spiral lattice.
CRE, Wuppertal
The modular architecture of high power solid state rf amplifiers for the frequency range of 72 to 3000MHz is described. The characteristic features of the modular components are presented, focusing on the multi transistor amplifier modules delivering a power in the 0.5 to 1.5 kW range, the transmission line combiner system combining up to 150 amplifier modules, the monitoring of the rf power flow in the system and other relevant performance parameters, as well as the heat exchanger concept and the digital amplifier control system.
AccSys, Pleasanton, California
AccSys has been built proton LINACs for medical applications such as Proton Beam Therapy (PBT), Positron Emission Tomography (PET) radioisotope production, and Boron Neutron Capture Therapy (BNCT). We will review the systems those have been shipped: For the PBT application, 6 systems have been shipped and under operation; for PET application, 5 systems have been shipped; for BNCT research application, one system has been shipped. We will also talk about high current proton linacs desired for BNCT and PET applications.
Hitachi, Ltd., Energy and Environmental Systems laboratory, Hitachi-shi, Ibaraki-ken
Hitachi Ltd., Power & Industrial Systems, 1-1, Saiwai-cho, 3-chome
Hitachi, Ltd., Energy and Environmental System Laboratory, Hitachi-shi
Slow cycle synchrotron system for cancer therapy is presented to realize the pencil beam scanning with carbon and proton. The designed synchrotron’s circumference is 60m and the maximum beam energies are 480MeV/u for carbon and 250MeV for proton. These energies correspond to the beam range of 35cm in water. In the treatment system with the present synchrotron, the discrete spot scanning scheme for lateral irradiation is employed using fast beam ON/OFF that is characteristic of the RF driven slow beam extraction from the synchrotron. Distal dose distribution is controlled with energy stacking technique, which is superimposing various bragg peaks which are controlled with the energy of the beam accelerated by the synchrotron. Furthermore, respiratory-gated operation with high throughput will be realized by the variable flat top length and timing for the beam extraction.
ITEP, Moscow
All known ion beam transport systems for medical applications with or without GANTRY are very large, complicated and expensive. Its cost is comparable with accelerator facility itself. It stimulates search of beam transport and distribution systems that allow reducing their cost and sizes considerably keeping treatment efficiency. Two such transport system are considered in the present paper. The first one is based on bend magnets that are rotated around their center of mass with movement of patient in horizontal position around of magnets. The second one uses stationary magnets with movement of patient in horizontal position in vertical plane. It is shown that the proposed ion transport systems provide treatment efficiency comparable with GANTRY at considerably lower sizes, mechanical complexity and cost.
JAEA, Tokai-mura
JAEA/Kansai, Kyoto
Toshiba, Tokyo
Kyoto ICR, Uji, Kyoto
Hokkaido University, Sapporo
The cancer treatment with hadron beams continues to be made as hadron treatment facilities are being developed around the globe with state-of-the-art accelerator technology. The generation of energetic protons and ions from laser-plasma interactions, has made laser-driven hadron radiotherapy a subject of strong interest. Proton bunches with high peak current and ultralow emittance are typical of ultrafast laser-foil interactions. However, these bunches also exhibit large divergence and energy spread. Photo Medical Research Center (PMRC) of JAEA was recently established to address the challenge of the laser-driven ion accelerator development for hadron therapy. Our mission at PMRC is to develop integrated, laser-driven ion accelerator systems (ILDIAS) that demonstrate desired beam characteristics for such therapy. We used the Phase and Radial Motion in Ion Linear Accelerators (PARMILA) design software which was originally developed as a numerical tool to design and simulate beam performance. This report will discuss beam specifications of laser-driven ion accelerators using PARMILA.
KAERI, Daejon
Kyungpook National University, Daegu
KIRAMS, Seoul
Funding: This work was perfomed as a part of the Proton Engineering Frontier Project and supported by the ministry of Education, Science and Technology of Korea.
A prototype LEPT(Low Energy Proton Therapy) system was developed and established at the MC-50 cyclotron in 2007. Some of the users of the PEFP (Proton Engineering Frontier Project) has been requiring a irradiation system for in-vivo experiments for the beam utilization in the fieds of medical and biological sciences. We are studying on the possibility of in-vivo experiments the prototype LEPT system. The LEPT system consists of collimators, range shifter, modulator for SOBP, dose meaurement system, etc. The energy and current from the cyclotron was 45 MeV and a few nA. For the in-vivo experiments accurate control of dose rate and penetration depth range is essential. The other important issue is how we can control the irradiation area and depth with high uniform dose distribution. We investigated the dose rate and uniformity of dose distribution inside the sample using PMMA and water phantom. The dose was measured by using ionization chamber and GAF films. The dose rate was 0.2~1Gy/sec and the penetration depth was 10~15 mm. The further studies using small animals using this LEPT system will be done by the users.
KAERI, Daejon
Samsung SDI Co. Ltd., Gyeonggi-do
Kyungpook National University, Daegu
SAMSUNG SDI CO. LTD, Gyeonggi-do
Funding: This work was performed as a part of the Proton Engineering Frontier Project supported by the Ministry of Education, Science and Technology of Korea.
The sample activation during proton beam irradiation sometimes interrupt the measurement and investigation of the instant changes of the samples after irradiation. During the experiments for nano particle fabrications with ~35MeV and ~20uA, we found that the samples was highly activated after the proton beam irradiation. To investigate the source of the rdadiation from the samples, we measured the energy spectrum of gamma ray using HPGe spectroscopy. The results was compared to the calculated results by the MCNP code simulation. The sample was small amount of heavy metal dispersed in enthanol in the beaker made of quartz.
UCBL, Villeurbanne
IN2P3 IPNL, Villeurbanne
DIAM is a new experimental system created for study the processes initiated by protons impact upon clusters of biomolecules especially the mechanism resulting from ionization and fragmentation in a complex molecular nanosystem. The experimental setup is designed to analyse interactions of two beams: on the one hand, protons from an ECR source are accelerated and guided into a monochromatic beam of 20 to 150 kV and 1mA. On the other hand, a cluster source is mounted on a high tension plat-form (5 to 30 kV). In order to analyse the products of protons/cluster interaction of the 2 crossing beams, we use several detection system such as Electro spray Time of Flight (ESI-TOF) or mass spectrometers.
LANL, Los Alamos, New Mexico
Funding: Work performed under the auspices of the U.S. Department of Energy, under contract W-7405-ENG-36.
The WNR facility at LANSCE is preparing for a set of proton induced cross section measurements in support of the LANL Isotope Production Program. To determine the best way to produce particular isotopes, it is necessary to measure the production rate’s energy dependence. The first measurements will use a 197-MeV proton beam, which prompted recovery of the facility’s ability to transport multiple energy proton beams simultaneously to different experimental areas to ensure that an 800-MeV beam is available for Proton Radiography or Ultra-Cold Neutron experiments while a sample is irradiated with a lower energy beam for the cross section measurements. The ability to change the beam energy pulse-to-pulse was built into the original accelerator controls, but the multiple energy controls were unused for over a decade and the system was re-commissioned for this effort. These experiments form part of an effort to establish a capability for the measurement of cross sections in the 197 to 800 MeV energy range. The experiments are expected to provide the needed data for activities that may develop into a unique isotope production capability to compliment the existing 100-MeV IPF facility.
Manchester University, Manchester
UMAN, Manchester
University of Huddersfield, Huddersfield
Nuclear power production can benefit from the development of more comprehensive alternatives for dealing with long-term radioactive waste. One such alternative is an accelerator-driven subcritical reactor (ADSR) which has been proposed for both energy production and for burning radioactive waste. Here we investigate the effects of the size of the ADSR spallation target on the total neutron yield integrated over the neutron energy and emission angle. The contribution to the total neutron yield from the (n, xn) neutron interactions is evaluated at proton beam energies between 0.4 and 2 GeV. Calculations have been carried out with the GEANT4 simulation code using the Liege intranuclear cascade model and the results are compared to the the LAHET/MCNP code package predictions.
Manchester University, Manchester
UMAN, Manchester
It has been proposed to use a proton Fixed Field Alternating Gradient (FFAG) accelerator to drive an Accelerator Driven Subcritical Reactor (ADSR) as they have the potential to provide high current beams to energies needed, 500 MeV to 1 GeV. This paper describes the results of 6D simulations of acceleration in possible lattice designs to explore longitudinal acceptance. This is needed to evaluate accelerator duty cycle and options for acceleration such as harmonic number jumping.
TUB, Beijing
IHEP Beijing, Beijing
CIAE, Beijing
ANL, Argonne
KEK, Tsukuba
Funding: Supported by the “985 Project” of the Minister of Education of China, CAS Bairen Init. (KJCX2-YW-N22), CAS Overseas Outstanding Youth Program, and the National Natural Science Foundation (10628510).
During the past decades, large-scale national neutron sources are developed in Asia, Europe, and USA. Complementing such efforts, compact hadron beam complexes and neutron sources intended for universities and industrial institutes are proposed and established. Responding to the demands in China for multidisciplinary researches and applications using pulsed neutrons and protons, hadron therapy and radiography, and accelerator-driven sub-critical reactor systems (ADS) for nuclear waste transmutation, we here propose a compact yet expandable accelerator complex based on a proton source, a 3 MeV RFQ linac, and a 22 MeV DTL linac. A Be target with solid methane and room-temperature water moderators serve 6 neutron stations for imaging/radiography, irradiation, SANS, engineering powder diffraction, instrumentation, and therapy. The proton platform serves multiple stations for bio-applications, fuel cell and nano-applications, and space irradiation and detection. A rapid cycling synchrotron subsequently accelerates the beam to up to 300 MeV for proton therapy and radiography. Following the DTL linac with a superconducting RF linac and a sub-critical reactor offers an ADS test facility.
University of Huddersfield, Huddersfield
UMAN, Manchester
PSI, Villigen
CEA, Grenoble
STFC/RAL, Chilton, Didcot, Oxon
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
The current paper discusses possible designs for a high intensity stand alone muon source for muSR studies of condensed matter. In particular we shall focus upon the potential implementation of a new generation of high power but relatively compact and cost effective proton drivers based on non-scaling fixed field alternating gradient (ns-FFAG) accelerator technology. The technical issues which must be addressed are also considered.
University of Huddersfield, Huddersfield
STFC/RAL, Chilton, Didcot, Oxon
The pulsed muon channel of the ISIS facility at Rutherford Appleton Laboratory has been successfully commissioned and operated for many years as a tool for MuSR studies in condensed matter research. At the present time, the graphite target, of dimensions 50*50*7 mm oriented at 45 degrees to a proton beam of 800 MeV energy, gives 16000 surface muons per double proton pulse passing through the entrance aperture of the aluminium window which separates the muon beamlines from the main proton beam. Potential improvements to the target geometry, and optimisation of the design and estimated performance of the muon target are presented in this paper.
University of Huddersfield, Huddersfield
STFC/RAL, Chilton, Didcot, Oxon
MuSR science requires the availability of intense beams of polarised positive muons. At the ISIS pulsed muon facility at Rutherford Appleton Laboratory the muons are generated from a low Z thin slab graphite target inserted in the proton beam. We report on the use of the Monte Carlo simulation code Geant4 in simulations of the performance of the current muon target. The results are benchmarked against the experimental performance of the target.
IHEP Beijing, Beijing
China Spallation Neutron Source (CSNS) is a high power proton accelerator-based facility. Uncontrolled beam loss is a major concern in designing the high power proton accelerators to control the radio-activation level. For the Rapid Cycling Synchrotron (RCS) of the CSNS, the repetition frequency is too high for the longitudinal motion to be fully adiabatic. Significant beam loss happens during the RF capture and initial acceleration. To reduce the longitudinal beam loss, phase space painting is used in the RCS injection. This paper presents detailed simulation studies on the longitudinal motion in the RCS by using the ORBIT code, which include different beam chopping factors, momentum offsets, injection times and RF voltage patterns. With a trade-off between the longitudinal beam loss and transverse incoherent tune shift that will also result in beam losses, optimized longitudinal painting schemes are obtained.
CERN, Geneva
The PS2 is proposed as a replacement for the ageing PS and will provide proton beams with kinetic energies up to 50 GeV. It must also deliver Pb54+ ions, for which the revolution frequency swing will be more than a factor of two. The favoured rf scenario considers a 40 MHz accelerating system and is motivated by the possibility of chopping at up to 40 MHz in the SPL, the proposed proton injector. Using the same principal rf system for ions implies pushing for an unprecedented tuning range and the introduction of a new rf system in LEIR, the existing ion source. We present a solution to the disparate requirements of protons and ions based on a 40 MHz rf system with switchable tuning ranges to cover the large frequency swing required.
Fermilab, Batavia
Funding: Work supported by the Fermi Research Alliance, LLC under contract No. DE-AC02-07CH11359 with the U.S. Dept. of Energy.
Project-X is a leading candidate of the next major accelerator construction project at Fermilab. The mission need of Project-X is to establish an intensity frontier for particle physics research, or more precisely, to build a multi-MW proton source for neutrino and other particle studies. Coupled with an upgraded Main Injector (MI) and Recycler, an 8 GeV superconducting RF (SRF) H linac meets this need. However, a more cost effective approach would be a hybrid design, namely, a combination of a 2 GeV SRF linac and an 8 GeV rapid cycling synchrotron (RCS) in lieu of an 8 GeV SRF linac. This alternative design also meets the mission need but at a lower cost since a synchrotron is cheaper than a SRF linac. It retains the ability to use a 2 GeV SRF linac for ILC technology development. It reuses the existing Debuncher enclosure and Booster RF. The transport line of 2 GeV H particles is shorter than the present 8 GeV design. The requirement of a cryogenic beam screen can be eliminated. The efficiency of stripping foil is higher and injection loss (kJ) will be lower.
*W. Chou, “A Simple Transition-Free Lattice of an 8 GeV Proton Synchrotron,” this conference.
Fermilab, Batavia
Injection painting enables the mitigation of space charge and stability issues, and may be indispensable for the Project-X at Fermilab, delivering high-intensity proton beams to HEP experiments. Numerical simulations of multi-turn phase space painting have been performed for the FNAL Recycler Ring, including a self-consistent space charge model, lattice nonlinearities, H- stripping, particle loss and foil heating. Different painting waveforms were studied to build a uniform (KV-like distribution) and other phase space distributions.
Fermilab, Batavia
Funding: Work supported by Fermi Research Alliance, LLC under contract No. DE-AC02-07CH11359 with the United States Department of Energy.
Currently Main Injector delivers 330KW of beam power at 120 GeV by using multi-batch slip stacking. The beam power is expected to increase to 400KW after installing clearing gap kickers to eliminate the injection kicker gap loss. The plan to increase the beam power to 700KW for NOvA and the role of MI in Project-X (2.1MW operation) will be discussed.
Fermilab, Batavia
Muons, Inc, Batavia
Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The use of existing Fermilab facilities to provide beams for two muon experiments –- the Muon to Electron Conversion Experiment (Mu2e) and the Muon g-2 Experiment –- is under consideration. Plans are being pursued to be able to perform these experiments following the completion of the Tevatron Collider Run II with no impact to the on-going Main Injector neutrino program by using spare Booster cycles to provide 8.9 GeV/c protons on target. Utilizing the beam lines and storage rings used today for antiproton accumulation, beams can be prepared for these experiments with minimal disruption, reconfiguration or expansion of the Fermilab accelerator infrastructure. The proposed operational scenarios and required alterations to the complex are described.
Imperial College of Science and Technology, Department of Physics, London
STFC/RAL, Chilton, Didcot, Oxon
Multi MW Proton Driver in the few GeV range are required for a neutron spallation source being studied in the framework of the ISIS upgrade at RAL and for the production of muon beam for a Neutrino Factory. Although the requirements for the time structure of proton beams are different, we investigate the possibility to share the proton driver between the two facilities. We assume the beam for both facilities is accelerated in a linac followed by rapid cycling synchrotron (RCS) at 50 Hz repetition rate to 3.2 GeV. One part of the bunch train after extraction from the RCS can be sent to the neutron production target and the other part of the extracted beam can be sent to another RCS, where further acceleration and final bunch compression can be performed to meet the specification of the Neutrino Factory target. The preliminary study of the final bunch compression is presented.
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
J-PARC, KEK & JAEA, Ibaraki-ken
In J-PARC, Materials and Life Science Facility (MLF) is aimed at promoting experiments using the world highest intensity pulsed neutron and muon beams which are produced at a thick mercury target and a thin carbon graphite target, respectively, by 3-GeV proton beams. The first beam was achieved at the target without significant beam loss. To obtain the beam profile at the target, we applied an activation technique by using thin aluminum foil. In order to obtain reliable profile, it is required that a small number of shots for the beam adjustment and the beam stability. Since beam monitors works very well located at the beam transport line even in the first beam, the beam centralization can be finished by very small number of shots. The stability of beam for each pulse is recognized to be smaller than 1 mm. After many shots of irradiation, the 2-D beam profile can be obtained. It is found that the observed profile shows good agreement with the prediction calculation including the beam scattering at the proton beam window. The beam emittance is measured by the MWPM. It is found that the rms-beam emittance agree with the calculation by the SIMPSONS.
CERN, Geneva
IN2P3 IPNL, Villeurbanne
INFN/LNL, Legnaro (PD)
Istituto Nazionale di Fisica Nucleare, Milano
The CNGS facility (CERN Neutrinos to Gran Sasso) aims at directly detecting muon-neutrino to tau-neutrino oscillations. An intense muon-neutrino beam (1017 muon-neutrino per day) is generated at CERN and directed over 732 km towards the Gran Sasso National Laboratory, LNGS, in Italy, where two large and complex detectors, OPERA and ICARUS, are located. After a brief overview of the facility, the major events since its commissioning in 2006 will be discussed. Emphasis will be given on the design challenges and operation constraints coupled to such a high-intensity facility summarizing the acquired experience. Highlights of the 2008 operations, which was the first complete year of physics in CNGS with 1.78·1019 protons delivered on target, will be presented.
Fermilab, Batavia
MSU, East Lansing, Michigan
TRIUMF, Vancouver
PAC, Batavia, Illinois
UCR, Riverside, California
The quest for higher beam power and duty factor and precisely controlled beams at reasonable cost has generated world-wide interest in Fixed-field Alternating Gradient accelerators (FFAGs). A new concept in non-scaling FFAGs to stabilize the betatron tune is under development. The emphasis to date has been on electron and proton accelerators, yet many facilities utilize H- front ends. This concept naturally extends to H- FFAGs and under conditions of rapid acceleration, the FFAG functions essentially as a recirculating linac with a common-aperture arc. As such it may be suitable for replacement of aging H- linac sections. For a slow acceleration cycle, an H- FFAG machine can exploit H- techniques to control extraction and intensity, and represents an innovation in proton therapy accelerators. Prototype RF and magnet component design have been initiated. For ten-turn acceleration, the rf cavities in a 10-100 MeV FFAG cannot be re-phased on the revolution time scale, and local adjustment of the pathlength is the proposed approach. For slow acceleration, broad-band, low-frequency rf can be applied. The basic optics and components for such FFAGs are presented.
Fermilab, Batavia
A new experimental area, the Muon Test Area, has been constructed to develop, test, and verify muon ionization apparatus using the 400-MeV proton beam from the Fermilab Linac. Since muon-cooling apparatus is being developed for facilities that involve the capture, collection and cooling of ~1013 muons at a repetition rate of 15 Hz, conclusive tests require full Linac beam, or ~1013 protons/pulse at 15 Hz. A beamline has been designed which includes specialized insertions for linac beam diagnostics and beam measurements, greatly enhancing the functionality of the line in addition to providing beam for MTA experiments. Installation of the beamline is complete and first beam was achieved in November, 2008. The design, operational flexibility, and characteristics of the MTA beamline will be presented.
CERN, Geneva
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
STFC/RAL, Chilton, Didcot, Oxon
ORNL, Oak Ridge, Tennessee
BNL, Upton, Long Island, New York
PU, Princeton, New Jersey
Fermilab, Batavia
The MERIT experiment is a proof-of-principle test of a target system for high power proton beam to be used as front-end for a neutrino factory complex or a muon collider. The experiment took data in autumn 2007 with the fast extracted beam from the CERN Proton Synchrotron (PS) to a maximum intensity of about 30·1012 protons per pulse. We report results from the portion of the MERIT experiment in which separated beam pulses were delivered to a free mercury jet target with time intervals between pulses varying from 2 to 700 microseconds. The analysis is based on the responses of particle detectors placed along side and downstream of the target.
CERN, Geneva
The CERN PS Booster (PSB) produces a variety of beam flavours for the LHC. While the nominal LHC physics beams require 6 Booster bunches with intensities up to 1.6·1012 protons per bunch, during the LHC commissioning single bunch beams with variable intensities as low as 5·109 protons have to be provided reproducibly. The final transverse and in many cases also the final longitudinal beam characteristics have to be achieved already in the PSB and can be very demanding in terms of beam brightness and stability. The optimized production schemes for the different LHC beam flavours in the PSB and the achieved machine performance are presented. Experience with the first beams sent to the LHC in September 2008 is discussed. An overview of the first measured results with a new production scheme of the nominal LHC beam using single instead of double-batch beam transfer from the PSB to the PS is also given.
IAP, Frankfurt am Main
A chopper system for high intensity proton beams of up to 200 mA and repetition rates up to 250 kHz is under development at IAP to be tested and applied at the Frankfurt Neutron Source FRANZ. The chopper system consists of a fast kicker for transversal separation of the beams and a static septum magnet to lower the dynamic deflection angle. Multi-particle simulations and preliminary experiments are presented. The simulations were made using a Particle in Cell (PIC)-Code developed at IAP. It permits the study of collective effects of compensation and secondary electrons on the proton beam in time-dependent kicker fields. A magnetic kicker with high repetition rate would entail high power consumption while electrostatic deflection in combination with intense beams can lead to voltage breakdown. Therefore a Wien filter-type ExB configuration consisting of a static magnetic dipole field and a pulsed electric field to compensate the magnetic deflection is discussed. The 25 kV high voltage pulser (250 kHz, 100 ns) will apply fast MOSFET transistor technology in the primary circuit, while the high voltage is provided at the secondary circuit around a metglas transformer core.
LLNL, Livermore, California
TomoTherapy, Madison
CPAC, Madison
Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.
We are developing a compact proton accelerator for cancer treatment by using the dielectric high-gradient insulator wall technology. The goal is to fit the compact dielectric wall proton therapy machine inside a conventional treatment room. To make the proton dielectric wall accelerator (DWA) compact requires a compact proton source capable of delivering protons in a sub-ns bunch. We are testing all the essential DWA components, including the compact proton source, on the First Accelerator System Test (FAST), which is designed to be taken apart and rebuilt many times to increase system performance by using improved components. The proton source being investigated currently is a surface flashover source. Five induction cells with HGI in the acceleration gaps are used to provide the 300-keV, 20-ns injector voltage for the proton injector. The physics design and the configuration of the injector and FAST will be presented.
BNL, Upton, Long Island, New York
The Brookhaven AGS Main Magnet Power Supply is a thyristor control supply rated at 5.5KAmps, ±9KV. The peak magnet power is 50MW,which is fed from a motor/generator manufactured by Siemens. During rectify and invert operation, the P Bank power supplies are used. During the flattops the F Bank power supplies are used. The P Bank power supplies are fed from two 23MVA transformers and the F Bank power supplies are fed from two 5.3 MVA transformers. The fundamental frequency of the F Bank power supplies is 1440Hz while the P banks were 720Hz. It was very important to reduce the ripple during rectify to improve polarized proton operations. For this reason and also because the original transformers were 45 years old we replaced these transformers with new ones and we made the fundamental frequency of both P and F banks 1440 Hz. This paper will highlight the major hurdles that were involved during the installation of the new transformers. It will present waveforms while running at different power levels up to 6MW full load and show the transition from the F-Bank power supplies to the P-Banks and also show the improvements in ripple made on the P-Bank power supplies.
STFC/RAL/ISIS, Chilton, Didcot, Oxon
Funding: ISIS
The Extracted Proton beam line for the ISIS second target station has two 10 Hz pulsed magnet systems and a DC Septum magnet system which extract the protons from the existing 50 Hz beam line. The pulsed Kicker 1 magnet system deflects the beam 12.1 mrad, pulsed Kicker 2 deflects the beam 95 mrad and the DC Septum magnet system deflects the beam 307 mrad. This paper describes the topology, installation, testing and successful operation of each of the power supplies.
CERN, Geneva
The Multi-Turn Extraction, a new type of extraction based on beam trapping inside stable islands in the horizontal phase space, has been commissioned during the 2008 run of the CERN Proton Synchrotron. Both single- and multi-bunch beams with a total intensity up to 1.4×1013 protons have been extracted with efficiencies up to 98%. Furthermore, injection tests in the CERN Super Proton Synchrotron were performed, with the beam then accelerated and extracted to produce neutrinos for the CERN Neutrino to Gran Sasso experiments. The results of the extensive measurement campaign are presented and discussed in details.
CERN, Geneva
The implementation of new Multi-turn extraction at the CERN Proton Synchrotron required major hardware changes for the nearly 50-year old accelerator. The installation of new PFNs and refurbished kicker magnets for the extraction, new sextupole and octupole magnets, new power converters, together with an in-depth review of the machine aperture leading to the design of new vacuum chambers was required. As a result, a heavy programme of interventions had to be scheduled during the winter shut-down 2007-8. The newly installed hardware and its commissioning is presented and discussed in details.
Fermilab, Batavia
Muons, Inc, Batavia
Funding: Supported under DOE contract DE-AC02-07CH11359.
The Mu2e experiment has been proposed at Fermilab to measure the rate for muons to convert to electrons in the field of an atomic nucleus with unprecedented precision. This experiment uses an 8 GeV primary proton beam consisting of short (~100 nsec) bunches, separated by 1.7 μs. It is vital that out-of-bunch beam be suppressed at the level of 10-9 or less. Part of the solution to this problem involves a pair of matched dipoles operating resonantly at half the bunch rate. There will be a collimation channel between them such that beam will only be transmitted when the fields are null. The magnets will be separated by 180 degrees of phase advance such that their effects cancel for all transmitted beam. Magnet optimization considerations will be discussed, as will optical design of the beam line. Simulations of the cleaning efficiency will also be presented.
KEK, Tsukuba
Tokyo City University, Tokyo
NIRS, Chiba-shi
J-PARC (Japan Proton Accelerator Research Complex) is a new accelerator facility to produce MW-class high power proton beams at both 3GeV and 50GeV. The Main Ring (MR) of J-PARC can extract beams to the neutrino beam line and the slow extraction beam line for Hadron Experimental Facility. The slow extraction beam is used in various nuclear and particle physics experiments. A flat structure and low ripple noise are required for the spills of the slow extraction. We are developing the spill control system for the slow extraction beam. The spill control system consists of the extraction quadrupole magnets and feedback device. The extraction magnets consist of two kinds of quadrupole magnets, EQ (Extraction Q-magnet) which make flat beam and RQ (Ripple Q-magnet) which reject the high frequent ripple noise. The feedback system, which is using Digital Signal Processor (DSP), makes a ramping pattern for EQ and RQ from spill beam monitor. Here we report the construction status of the extraction magnets and the development of the feedback system.
KAERI, Daejon
Funding: This work is supported by the Ministry of Education, Science and Technology of Korea.
PEFP (Proton Engineering Frontier Project) beamlines will be supplied either 20-MeV or 100-MeV proton beams from the 100-MeV proton linear accelerator for beam applications. Each proton beam will be transported to 2 beamlines for industrial purpose and 3 beamlines for the researches. Beam distribution to 3 research beam lines will be conducted sequentially by programmable AC magnet. To provide flexibility of the irradiation conditions, each beam line is designed to have specific beam parameters. We have designed the beamlines to the targets for wide or focused beams, external or in-vacuum beams, and horizontal or vertical beams. The detail design of each beamline will be reported.
ORNL, Oak Ridge, Tennessee
Funding: *SNS is managed by UT-Battelle, LLC, for the U. S. Department of Energy under Contract No. DE-AC05-00OR22725.
Thin carbon foils used as a charge strippers for H־ ions have a limited life time and produce uncontrolled beam loss. Thus, foil based injection is one of the factors limiting beam power in high intensity proton rings. There is a possibility to replace such foils by laser-assisted stripping of negative hydrogen ions, a method developed and demonstrated at the SNS accelerator in Oak Ridge. In this paper we present progress in the physics and computation of H־ laser stripping. We present a physical model which includes such factors as the Stark effect, the polarization of the laser field, and the spontaneous relaxation and autoionization of hydrogen atoms in a strong electro-magnetic field. The model formulates a quantum mechanical problem that can be solved numerically using a module created for the PyORBIT parallel code developed at SNS.
ORNL, Oak Ridge, Tennessee
University of Tennessee, Knoxville, Tennessee
ORNL RAD, Oak Ridge, Tennessee
Funding: SNS is managed by UT-Battelle, LLC, for the U.S. DOE under contract DE-AC05-00OR22725.
Nanocrystalline diamond foils are now in use for injection stripping at the SNS. Typical dimensions are 17x25 mm x 300-350 ug/cm2 physical thickness. Corrugations of the foil help to maintain flatness, but after ca. 300 C of injected charge curling is observed. We continue to experiment with foil preparation techniques. To allow independent stripper foil testing without impacting SNS neutron production, we have assembled a 30 keV electron beam foil test facility to investigate foil lifetimes. At 30 keV acceleration, a 1.6 mA/mm2 electron beam imparts the same peak heating load to a carbon foil as the injected and circulating current of the 1.4 MW SNS. At this energy the electron stopping distance is approximately six-fold longer than the foil thickness. The electron gun is capable of 5 mA current in a focal spot less than 1 mm FWHM diameter. Two foil stations are available for sequential tests, and foils can be rotated relative to the beam to vary their effective thickness. A 6 us risetime optical pyrometer records instantaneous foil temperatures over the 60 Hz heating profile. A CCD camera captures foil images over time. Results using this test stand are described.
ANL, Argonne
Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.
The development of a uniform and stable high velocity, thin liquid lithium film stripper is essential for the Facility for Rare-Isotope Beams (FRIB) Project. The formation of such a film has been demonstrated recently at ANL. Film thickness should be measured, and its temporal and spatial stability under high power ion beam irradiation should be verified. Intense beams of light ions generated by the FRIB prototype injector can be used for this task. The injector consists of an ECR ion source followed by a LEBT. A DC 3.3 mA/75 kV proton beam has been generated at the LEBT output. Proton beam power will be brought to required level by adding the second acceleration tube. A low energy electron beams (LEEB) technique, based on the thickness-dependent scattering of the electrons by the film, has been proposed as a fast-response on-line film thickness monitoring. A LEEB test bench has been built to verify this technique. The transmission of electrons through the carbon foils of different thicknesses was measured and compared with results of CASINO simulations. Agreement between the experimental and numerical results allows quantitative measurements of film thickness using the LEEB.
Fermilab, Batavia
Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
We have designed and commissioned a system which blows up the transverse emittance of the anti-proton beam without affecting the proton beam. It consists of a bandwidth limited noise source centered around the betatron tune, a power amplifier and a directional stripline kicker. The amount of blow up is controlled by the amount of energy delivered to the anti-protons betatron bands.
STFC/RAL/ISIS, Chilton, Didcot, Oxon
Funding: Supported by STFC/RAL/ASTeC and by EC Research Infrastructure Activity (FP6) "Structuring the European Research Area" programme (CARE, contract number RII3-CT-2003-506395).
A description is given of the development of a slow-wave chopper structure for the 3.0 MeV, 60 mA, H‾ MEBT on the RAL Front-End Test Stand (FETS). Two candidate structures, the so called RAL ‘Helical’ and ‘Planar’ designs have been previously identified, and are being developed to the prototype stage. Three test assemblies have been designed by modelling their high frequency electromagnetic properties in the time domain, using a commercial 3D code, and their subsequent manufacture, using standard NC machining practice, has helped to validate the selection of machine-able ceramics and copper alloys. In addition, an electro-polishing technique has been developed that enables the ‘fine tuning’ of strip-line characteristic impedance, and edge radius. Measurements of the transmission line properties of the ‘Helical’ and ‘Planar’ test assemblies are presented.
BNL, Upton, Long Island, New York
Funding: Work supported by Brookhaven Science Associates, LLC underContract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In order to cross more rapidly the 82 weak resonances caused by the horizontal tune and the partial snakes, we plan to jump the horizontal tune 82 times during the acceleration cycle, 41 up and 41 down*. To achieve this, the magnets creating this tune jump will pulse on in 100 micro-seconds, hold the current flat for about four milli-seconds and zero the current in another 100 micro-seconds. The magnets are old laminated beam transport magnets with longitudinal shims closing the aperture to reduce inductance and power supply current. The power supply uses a high voltage capacitor discharge to raise the magnet current, which is then switched to a low voltage supply, and then the current is switched back to the high voltage capacitor to zero the current. The current in each of the magnet pulses must match the order of magnitude change in proton momentum during the acceleration cycle. The magnet, power supply and cabling will be described with coast saving features and operational experience.
*Overcome Horizontal Depolarizing Resonances in the AGS with Tune Jump
Fermilab, Batavia
Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
A high voltage modulator has been built and installed at Fermi National Accelerator Laboratory for the purpose of driving the gun anode of the Tevatron Electron Lens (TEL). It produces a defined voltage for each of the 36 (anti)proton bunches. This modulator employs five transformers to produce high voltage at a high repetition rate and high duty factor. It is capable of outputting sustained complex waveforms having peak voltages over 6 kV and average periodic rates up to 450 kHz with voltage transitions occurring at 395 ns intervals. This paper describes key aspects of the hardware design and performance.
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
The main circuit of the switching power supplies for the injection bump system is composed of multiple-connection of the IGBT assemblies. The element of the IGBT assembly, which is the power supply of the shift bump-magnets, is a type of 3300V-1200A and 6 kHz in elementary frequency. The power supply has the output performance of 20 kA / 6.6 kV. The synthetic frequency of the multiple-connection assemblies is over 48 kHz and the tracking error less than 1 % is proved. The beam commissioning test of long-term operation for about three-week was performed. The deviation of the exciting current from the programmed current pattern has been confirmed less than 1%. The peculiar characteristic of the pulse power supply has been obtained by the analysis on the frequency response of the exciting current and the magnetic field. In the FFT analytical result of the magnetic field, the peaks of 48 kHz and its higher harmonics that are related to the switching frequency was observed. The ground loop current and the voltage were also measured.
PSI, Villigen
At PSI, a new and very intensive Ultra-Cold Neutron (UCN) source based on the spallation principle will start operation at the end of 2009. From then on, two neutron spallation sources - the continuous wave SINQ and the macro-pulsed UCN source will be running concurrently at PSI. The 590 MeV, 1.2 MW proton beam will be switched towards the new spallation target for about 8 s every 800 s. This operation can be accomplished by means of a fast kicker magnet with a rise-time shorter than 1 ms. A beam dump capable of absorbing the full-intensity beam for a few milliseconds has been installed after the last bending magnet so that the kicking process and the beam diagnostic can be checked well before the UCN facility will be ready for operation. Recent tests have demonstrated the capability of switching the 1.2 MW beam with negligible losses and to center it through the beam line by using fast beam position monitors. Much longer beam pulses (up to 6 seconds) with reduced beam intensity have also been performed successfully.
CERN, Geneva
The PS2 will replace the present CERN-PS as the LHC pre-injector. It will have twice the PS energy and twice the circumference. Extensive design optimization is presently ongoing with the aim of starting the PS2 construction around 2011 and delivering beams for physics in 2017. The talk describes the various PS2 design constraints, the optimization steps, and the path towards the final design.
STFC/RAL, Chilton, Didcot, Oxon
Exeter University, Exeter, Devon
Gericke LTD, Ashton-under-Lyne
This paper describes the potential of fluidised powdered material for use as a particle production target in high power particle accelerator based facilities. In such facilities a multi-MW proton beam is required to interact with a dense target material in order to produce sub-atomic particles, e.g. neutrons for a neutron source or pions for a so-called conventional neutrino beam, a neutrino factory or a muon collider. Experience indicates that thermal transport, shock wave and radiation damage will limit the efficiency and reliability of facilities utilising solid targets at around 1 MW beam power. Consequently liquid mercury has been adopted as the target technology for the latest neutron facilities SNS and J-SNS at ORNL and Tokai respectively, and is the baseline for a neutrino factory and muon collider. However mercury introduces new problems such as Cavitation Damage Erosion. This paper discusses how a fluidised powder target may combine many of the advantages of a liquid metal with those of a solid, and describes an experimental programme at RAL currently underway to implement this technology.
ORNL, Oak Ridge, Tennessee
University of Tennessee, Knoxville, Tennessee
MIT Lincoln Laboratory, Boston MA
Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.
Investigations of the rf properties of certain twisted waveguide structures show that they support favorable accelerating fields. This makes them potential candidates for accelerating cavities. Using the particle tracking code, ORBIT, We examine the beam - rf interaction in the twisted cavity structures to understand their beam transport and acceleration properties. The results will show the distinctive properties of these new structures for particle transport and acceleration, which have not been previously analyzed.
BNL, Upton, Long Island, New York
Fermilab, Batavia
Funding: Work supported by U.S. DOE under contract No DE-AC02-98CH1-886
Long-range and head-on beam-beam effects are expected to limit the LHC performance with design parameters. To mitigate long-range effects current carrying wires parallel to the beam were proposed. Two such wires are installed in RHIC where they allow studying the effect of strong long-range beam-beam effects, as well as the compensation of a single long-range interaction. The tests provide benchmark data for simulations and analytical treatments. To reduce the head-on beam-beam effect electron lenses were proposed for both the LHC and RHIC. We present the experimental long-range beam-beam program and report on head-on compensations studies at RHIC, which are primarily based on simulations.
Fermilab, Batavia
MSU, East Lansing, Michigan
St. Petersburg State University, St. Petersburg
Innovations in computer techniques in combination with increased sophistication in modeling are required to accurately understand, design and predict high-energy, and, in particular, the new generation of frontier accelerators for HEP and other applications. A recently identified problem lies in the simulation and optimization of FFAGs and related devices, for which currently available tools provide only approximate and inefficient simulation. For this purpose new tools are being developed within the advanced accelerator code COSY INFINITY to address complex, specific electromagnetic fields, including high-order fringe fields, out of plane fields, edge effects, and general field profiles; tools linked to modern global optimization techniques that can further accommodate the ultra-large emittances of proposed beams to allow efficient probing of very high dimensional parameter space. This new set of tools based on modern techniques and simulation approaches will be furnished with modern GUI-based user interfaces.
KEK, Ibaraki
MELCO SC, Tsukuba
JAEA, Ibaraki-ken
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
J-PARC, KEK & JAEA, Ibaraki-ken
Beam commissioning of the J-PARC MR has been going on from May 2008. The beam was one bunch of 4·1011 protons, nearly one hundredth of the design value. Here describe performances of the beam diagnostic devices: DCCT's, BPM's, BLM's, profile monitors and tune meters. Diagnostic design for the design intensity will be also included.
CERN, Geneva
During the 2008 LHC injection synchronisation tests and the subsequent days with circualting beam, the majority of the LHC beam instrumentation systems were capable of measuring their first beam parameters. This includes the two large, distributed, beam position and beam loss systems, as well as the scitillating and OTR screen systems, the fast and DC beam current transformer systems, the tune measurement system and the wire scanner system. The fast timing system was also extensively used to synchronise most of this instrumentation. This paper will comment on the results to date, some of the problems observed and improvements to be implemented before the next LHC run.
CERN, Geneva
The LHC stored beam contains 362 MJ of energy at the top beam energy of 7 TeV, presenting a significant risk to the components of the machine and the detectors. In response to this threat, a sophisticated system of machine protection has been developed to minimize the danger, and detect potentially dangerous situations. In this paper, the protection of the experiments in the LHC from the machine is considered, focusing on pilot beam strikes on the experiments during injection and on the dynamics of hardware failure with a circulating beam, with detailed time-domain calculations performed for LHC ring power converter failures and magnet quenches. The prospects for further integration of the machine protection and experimental protection systems are considered,along with the risk to near-beam detectors from closed local bumps.
OXFORDphysics, Oxford, Oxon
Imperial College of Science and Technology, Department of Physics, London
UMAN, Manchester
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
Brunel University, Middlesex
STFC/RAL/ISIS, Chilton, Didcot, Oxon
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
JAI, Oxford
Cockcroft Institute, Lancaster University, Lancaster
Manchester University, Manchester
Gray Cancer Institute, Northwood, Middlesex
Funding: EP/E032869/1
AMELA (Particle Accelerator for MEdicaL Applications) is a newly developed fixed field accelerator, which has capability for rapid beam acceleration, which is interesting for practical applications such as charged particle therapy. PAMELA aims to design a particle therapy facility using Non-Scaling FFAG technology, with a target beam repetition rate of 1kHz, which is far beyond that of conventional synchrotron. To realize the repetition rate, the key component is rf acceleration system. The combination of a high field gradient and a high duty factor is a significant challenge.  In this paper, options for the system and the status of their development are presented.
LANL, Los Alamos, New Mexico
JLAB, Newport News, Virginia
Funding: DTRA
805 MHz elliptical SRF cavities have been used for SNS as the first application for protons. At LANL, an R&D started to explore a capability of getting high-gradient cavities (40-50 MV/m) at this frequency for the future applications such as proton and muon based interrogation testing facility added to the LANSCE accelerator and a power upgrade of the LANSCE accelerator for the fission and fusion material test station. Optimized cell designs for “standard”, “low-loss” and “re-entrant” shapes, cavity test results for “standard” single-cell cavities with temperature mapping as well as surface inspection results will be presented.
CRE, Wuppertal
DESY, Hamburg
For future applications in Light Sources and Large Scale Linear Accelerators we have developed a fully digital LLRF system which overcomes the intrinsic problems of analogue and semi digital LLRF systems by realizing all functions in the high speed cores of FPGAs. Due to its modular design using either the ATCA or the VME form factor the LLRF system can be configured conveniently according to the specific requirements of the accelerator to control the rf field in individual resonators or in a combination of cavities. The LLRF input stage can be custom designed for rf frequencies of up to 3.9 GHz. The hardware and software architectures of the Cryoelectra digital LLRF control system are presented.
BNL, Upton, Long Island, New York
Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
In preparation for the RHIC polarized proton run 2009, simulations were carried out to evaluate the million turn dynamic apertures for different beta*s at the proposed beam energies of 100 GeV and 250 GeV. One goal of this study is to find out the best beta* for this run. We also evaluated the effects of the second order chromaticity correction. The second order chromaticties can be corrected with the MAD8 Harmon module or by correcting the horizontal and vertical half-integer resonance driving terms.
CERN, Geneva
Several forwards detectors have been installed in the LHC long straight sections located on each side of the experimental caverns. Most of these detectors have been designed by the LHC experiments to study the forwards physics while some of them are dedicated to the measurement of the LHC luminosity. The integration and installation of the forwards detectors have required an excellent coordination between the experiments and the different CERN groups involved into the design and installation of the LHC accelerator. In some cases the integration of these detectors has required a modification of the standard beam lines in order to maximise the physics potentiality of the detectors. Finally, additional systems have been installed in the LHC tunnel to ensure the operation of the forwards detectors in a high radiation environment.
CERN, Geneva
The Large Hadron Collider extends the present state-of-the-art in stored beam energy by 2-3 orders of magnitude. A sophisticated system of collimators is implemented along the 27 km ring and mainly in two dedicated cleaning insertions, to intercept and absorb unavoidable beam losses which could induce quenches in the superconducting magnets. 88 collimators per beam are initially installed for the so called Phase 1. An optimized strategy for the commissioning of this considerable number of collimators has been defined. This optimized strategy maximizes cleaning efficiency and tolerances available for operation, while minimizing the required beam time for collimator setup and ensuring at all times the required passive machine protection. It is shown that operational tolerances from collimation can initially significantly relaxed.
Fermilab, Batavia
Funding: Work supported by Fermi Research Alliance, LLC, under contract No. DE-AC02-07CH11359 with the U.S. Department of Energy.
With a fully-operational high-efficient collimation system in the LHC, nuclear interactions of circulating protons with residual gas in the machine beam pipe can be a major sources of beam losses in the vicinity of the collider detectors, responsible for the machine-induced backgrounds. Realistic modeling of elastic and inelastic interactions of 7-TeV protons with nuclei in the vacuum chamber of the cold and warm sections of the LHC ring - with an appropriate pressure profile - is performed with the STRUCT and MARS15 codes. Multi-turn tracking of the primary beams, propagation of secondaries through the lattice, their interception by the tertiary collimators TCT as well as properties of corresponding particle distributions at the CMS and ATLAS detectors are studied in great detail and results presented in this paper.
Fermilab, Batavia
Tevatron Electron Lenses (TEL) have reliably demonstrated correction of the bunch-to-bunch tune shift induced by long-range beam-beam interactions. The second and most important intended application of TEL is compensation of the nonlinearity of head-on beam-beam force. We report on the first studies of head-on beam-beam compensation with the second generation Gaussian profile TEL. We evaluate the effect of TEL on beam life time and emittance and compare the observed results with simulations.
Fermilab, Batavia
Funding: Work supported by the U.S. Department of Energy under contract No. DE-AC02-07CH11359
A novel high voltage modulator had been under development for 1.5 years. It was completed tested on the bench and became a part of the TEL2 system in October 2008. The modulator is used to drive the electron gun anode. We provide technical details on the stacked transformer modulator, analyze its performance and discuss the design challenges. The results of the beam studies made possible by the new high voltage modulator are reported.
Fermilab, Batavia
Abstract The compensation of long-range beam-beam interactions with current carrying wires in the Large Hadron Collider (LHC) is studied by multi-particle tracking. In the simulations, we include the effect of long-range collisions together with the nonlinearities of IR triplets, sextupoles, and head-on collisions. The model includes the wires placed at the locations reserved for them in the LHC rings. We estimate the optimal parameters of a wire for compensating the parasitic beam-beam force by long-term simulations of beam lifetime.
Fermilab, Batavia
A beam-beam simulation code (BBSIMC) has been developed to study the interaction between counter moving beams in colliders and its compensation through a low energy electron beam. This electron beam is expected to improve intensity lifetime and luminosity of the colliding beams by reducing the betatron tune shift and spread from the head-on collisions. In this paper we discuss the results of beam simulations with the electron lens in the Relativistic Heavy Ion Collider (RHIC). We study the effects of the electron beam profile and strength on the betatron tunes, dynamic aperture, frequency diffusion and beam lifetime.
Fermilab, Batavia
Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
The recent record-setting performance of the Fermilab Tevatron is the culmination of a long series of efforts to optimize the many parameters that go into generating integrated luminosity for the colliding beams experiments. While several complex numerical computer models exist that are used to help optimize the performance of the Tevatron collider program, here we take an analytical approach in an attempt to illustrate the most fundamental aspects of integrating luminosity in the Tevatron. The essential features, such as weekly integrated luminosity and store length optimization, can be understood in a transparent way from basic operational parameters such as antiproton stacking rate and observed beam emittance growth rates in the Tevatron. Comparisons of the analytical model with operational data are provided.
Fermilab, Batavia
Funding: Work supported by the United States Department of Energy under Contract No. DE-AC02-07CH11359
Head-on beam-beam effect may become a major performance limitation for the LHC in one of the upgrade scenarios. Given the vast experience gained from the operation of Tevatron electron lenses, a similar device provides significant potential for mitigation of beam-beam effects at the LHC. In this report we present the results of simulation studies of beam-beam compensation and analyze potential application of electron lense at LHC and RHIC.
Fermilab, Batavia
Funding: Work supported by the United States Department of Energy under Contract No. DE-AC02-07CH11359
Significant difference in transverse size of the proton and antiproton bunches at collision points is known to cause deterioration of the larger (proton) beam life time at Tevatron. The reason is believed to be in the combination of large betatron tune spread induced by the high nonlinearity of the beam-beam force, and limited tune space. We consider the prospects for application of hollow electron beam for beam-beam tune spread suppression.
LAL, Orsay
CERN, Geneva
For luminosity and total cross section measurement, the standard LHC physics optics has been modified for the ATLAS experiment in the so-called high beta optics with a beta star of 2600m. The high beta optics takes into account the whole LHC ring. Protons are, then, tracked from the Interaction Point to the detectors. Tolerances on the beta star are given and the effect of misalignment errors is checked. We show the final High beta optics used and the impact of the misalignment effect on the measurement.
PSI, Villigen
CERN, Geneva
LBNL, Berkeley, California
Under nominal operational conditions, the LHC bunches experience small unavoidable offset at the collision points caused by long range beam-beam interactions. Although the geometrical loss of luminosity is small, one may have to consider an increase of the beam transverse emittance, leading to a deterioration of the experimental conditions. In this work we evaluate and understand the dynamics of beam-beam interactions with static offsets at the collision point. A study of the emittance growth as a function of the offset amplitude in collisions is presented. Moreover, we address the effects coming from the beam parameters such as the initial transverse beam size, bunch intensity and tune.
BNL, Upton, Long Island, New York
Funding: Work performed under the auspices of the US DOE.
In the recent years the peak luminosity of the RHIC polarized proton run has been improved. However, as a consequence, the luminosity lifetime is reduced. The beam emittance growth during the beam storage is a main contributor to the luminosity lifetime reduction, and it seems to be caused mainly by the beam-beam effect during collision. It is, therefore, important to better understand the beam-beam collision effects in RHIC with the aid of particle tracking codes. A simulation study of the emittance growth is performed with RHIC machine parameters using the LIFETRAC code*. The initial results of this study were reported in an earlier paper**. In order to achieve a better understanding and to provide guidance for future RHIC operations, we present an in depth investigation of the emittance growth for a range of RHIC operation tunes, bunch lengths and initial emittance. The simulation results are also compared to the available data from experimental measurements.
*D.Shatilov, et al.,"Lifetrac Code for the Weak-Strong Simulation of the Beam-Beam Effects in Tevatron",PAC05 proc.
**J.Beebe-Wang,“Emittance Growth due to Beam-Beam Effect in RHIC”,PAC07 Proc.
BNL, Upton, Long Island, New York
Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Medium Energy eRHIC (MeRHIC), the first stage design of eRHIC, includes a multi-pass ERL that provides 4GeV high quality electron beam to collide with the ion beam of RHIC. It delivers a minimum luminosity of 1032 cm-2s-1. Beam-beam effects present one of major factors limiting the luminosity of colliders. In this paper, both beam-beam effects on the electron beam and the proton beam in MeRHIC are investigated. The beam-beam interaction can induce a head-tail type instability of the proton beam referred to as the kink instability. Thus, beam stability conditions should be established to avoid proton beam loss. Also, the electron beam transverse disruption by collisions has to be evaluated to ensure that the beam quality is good enough for the energy recovery pass. The relation of proton beam stability, electron disruption and consequential luminosity are carried out after thorough discussion.
BNL, Upton, Long Island, New York
Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
Beam-beam effects present one of major factors limiting the luminosity of colliders. In the linac-ring option of the eRHIC design, an electron beam accelerated in a superconducting energy recovery linac collides with a proton beam circulating in the RHIC ring. Some specific features of beam-beam interactions should be carefully evaluated for the linac-ring configuration. One of the most important effects on ion beam stability originates from a strongly focused electron beam because of the beam-beam force. This electron pinch effect makes the beam-beam parameter of the ion beam several times larger than the design value, and leads to the fast emittance growth of the ion beam. The electron pinch effect can be controlled by adjustments of electron lattice and the incident emittance. We present results of simulations optimizing ion beam quality in the presence of this pinch effect.
BNL, Upton, Long Island, New York
The luminosity of the eRHIC ring-ring design is limited by the beam-beam effect exerted on the electron beam. Recent simulation studies have shown that the beam-beam limit can be increased by means of an electron lens that compensates the beam-beam effect experienced by the electron beam. This scheme requires proper design of the electron ring, providing the correct betatron phase advance between interaction point and electron lens. We review the performance of the eRHIC ring-ring version and discuss various parameter sets, based on different cooling schemes for the proton/ion beam.
BNL, Upton, Long Island, New York
MIT, Middleton, Massachusetts
Funding: Work performed under US DOE contract DE-AC02-98CH1-886
Design of a medium energy electron-ion collider (MEeIC) is under development at Collider-Accelerator Department, BNL. The design envisions a construction of 4 GeV electron accelerator in a local area inside the RHIC tunnel. The electrons will be produced by a polarized electron source and accelerated in the energy recovery linac. Collisions of the electron beam with 100 GeV/u heavy ions or with 250 GeV polarized protons will be arranged in the existing IP2 interaction region of RHIC. The luminosity of electron-proton collisions at 1032 cm-2 s-1 level will be achieved with 40 mA CW electron current with presently available parameters of the proton beam. Efficient cooling of proton beam at the collision energy may bring the luminosity to 1033 cm-2 s-1 level. The important feature of the MEeIC is that it would serve as first stage of eRHIC, a future electron-ion collider at BNL with both higher luminosity and energy reach. The majority of the MEeIC accelerator components will be used for eRHIC.
FZJ, Jülich
IKP, Mainz
ELSA, Bonn
BNL, Upton, Long Island, New York
DELTA, Dortmund
The feasibility of a polarized Electron-Nucleon Collider (ENC) with a center-of-mass energy up to 13.5 GeV for luminosities above 2·1032 cm-2 s-1 is presently under consideration. The proposed concept integrates the planned 14 GeV High-Energy Storage Ring (HESR) for protons/deuterons and an additional 3 GeV electron ring. Calculations of cooled beam equilibria including intra-beam scattering and beam-beam interaction have been performed utilizing the BetaCool code. A special design of the interaction region is required to realize back-to-back operation of the HESR storage ring together with the elaborated collider mode. For polarized proton/deuteron beams additional equipment has to be implemented in several machines of the acceleration chain and the HESR to preserve the beam’s polarization. A scheme for polarized electrons is still under investigation. In this presentation the required modifications and extensions of the HESR accelerator facility at the future International Facility for Antiproton and Ion Research (FAIR) are discussed and the proposed concept is presented.
JLAB, Newport News, Virginia
LBNL, Berkeley, California
Funding: (1) Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 (2) Supported by the U. S. Department of Energy under Contract no. DE-AC02-05CH11231.
The collective beam-beam effect can potentially cause a rapid growth of beam sizes and reduce the luminosity of a collider to an unacceptably low level. The ELIC, a proposed ultra high luminosity electron-ion collider based on CEBAF, employs high repetition rate crab crossing colliding beams with very small bunch transverse sizes and very short bunch lengths, and collides them at up to 4 interaction points with strong final focusing. All of these features can make the beam-beam effect challenging. In this paper, we present simulation studies of the beam-beam effect in ELIC using a self-consistent strong-strong beam-beam simulation code developed at Lawrence Berkeley National Laboratory. This simulation study is used for validating the ELIC design and for searching for an optimal parameter set.
ORNL, Oak Ridge, Tennessee
CERN, Geneva
BNL, Upton, Long Island, New York
PU, Princeton, New Jersey
Funding: U.S. Department of Energy contract DE-AC05-00OR22725
Operation of a mercury jet delivery system is presented. The delivery system is part of the Mercury Intense Target (MERIT) Experiment, a proof-of-principle experiment conducted at CERN in 2007 which demonstrated the feasibility of using an unconstrained jet of mercury as a target for a future Neutrino Factory or Muon Collider. The Hg system was designed to produce a 1-cm-diameter, 20 m/s Hg jet inside a high-field (15 Tesla), 15-cm-bore solenoid magnet. A high-speed optical diagnostic system allowed observation of the interaction of the jet with both 14- and 24-GeV proton beams. Performance of the Hg system during the in-beam experiment will be presented.
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
The goal of a Neutrino Factory is to generate intense beams of neutrinos from muon decay inorder to study CP violation in the Standard Model, the mass hierarchy, and the neutrino mixing angle θ13. Intense muon beams are created and accelerated in a system of particle accelerators to energies of 20-50 GeV. They are then allowed to decay in dedicated storage rings with long straight sections aligned on suitably chosen long-range detectors. A variety of geometries are possible, and their design and construction present demanding challenges for accelerator R & D, covering not only beam optics but touching on geological and engineering aspects of constructing almost vertical storage rings several hundred metres below the Earth's surface. The basic ideas are described in this paper and are demonstrated by three possible models developed in recent years.
UCLA, Los Angeles, California
BNL, Upton, Long Island, New York
Funding: DOE
A study of target parameters for a high-intensity, liquid mercury jet target system for a neutrino factory or muon collider is presented. Using the MARS code, we simulate particle production initiated by incoming protons with kinetic energies between 2 and 100 GeV. For each proton beam energy, we optimize the geometric parameters of the target: the mercury jet radius, the incoming proton beam angle, and the crossing angle between the mercury jet and the proton beam. The number of muons surviving through an ionization cooling channel is determined as a function of the proton beam energy
BNL, Upton, Long Island, New York
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
STFC/RAL, Chilton, Didcot, Oxon
ORNL, Oak Ridge, Tennessee
CERN, Geneva
PU, Princeton, New Jersey
Fermilab, Batavia
We report on the analysis of data collected from the optical diagnostics of the MERIT experiment which was run at CERN in the fall of 2007. The breakup of the free mercury jet resulting from the impact of intense proton beams from the CERN PS within a magnetic field environment is described.
CERN, Geneva
While the Large Hadron Collider (LHC) at CERN is starting operation with beam, aiming to achieve nominal performance in the shortest term, the upgrade of the LHC interaction regions is actively pursued in order to enhance the physics reach of the machine. Its first phase, with the target of increasing the LHC luminosity to 2-3 1034 cm-2 s-1, relies on the mature Nb-Ti superconducting magnet technology and is intended to maximize the use of the existing infrastructure. The impact of the increased power of the collision debris has been investigated through detailed energy deposition studies, considering the new aperture requirements for the low-beta quadrupoles and a number of other elements in the insertions. Effective solutions in terms of shielding options and design/layout optimization have been envisaged and the crucial factors have been pointed out.
CERN, Geneva
INFN-Roma, Roma
BNL, Upton, Long Island, New York
The UA9 experiment will take place in 2009 at the CERN-SPS and will evaluate the feasibility of silicon crystals as primary collimators for a storage ring. A crystal placed at 6 σ from the beam core will deviate protons towards two roman pots and a tungsten absorber (TAL). In this paper the authors show simulations of the expected beam dynamics and of the capture efficiency into the secondary collimator. The result of these simulations will guide us in interpreting the experimental data expected in UA9.
CERN, Geneva
BNL, Upton, Long Island, New York
EPFL, Lausanne
The grazing function g is introduced – a synchrobetatron optical quantity that parametrizes the rate of change of total angle with respect to synchrotron amplitude for particles grazing a collimator or aperture. The grazing function is particularly important for crystal collimators, which have limited acceptance angles. The implications for RHIC, SPS, Tevatron and LHC crystal implementations are discussed. An analytic approximation is derived for the maximum value of g in a matched FODO cell, and is shown to be in good agreement with a realistic numerical example. The grazing function scales linearly with FODO cell bend angle, but to is independent of FODO cell length.
CERN, Geneva
A full scale prototype of the Large Hadron Collider (LHC) collimator was installed in 2004 in the CERN Super Proton synchrotron (SPS). During three years of operation the prototype has been used extensively for beam tests, for control tests and also to benchmark LHC simulation tools. This operational experience has been extremely valuable in view of the final LHC implementation as well as for estimating the LHC operational scenarios, most notably to establish procedures for the beam-based alignment of the collimators with respect to the circulating beam. This was made possible by installing in the SPS a first prototype of the LHC beam loss monitoring system. The operational experience gained at the SPS, lessons learnt for the LHC operation and various accelerator physics effects that could limit the efficiency of the collimator alignment procedures are presented.
CERN, Geneva
The UA9 experiment intends to assess the possibility of using bent silicon crystals as primary collimators to direct the beam halo onto a secondary absorber, thus reducing outscattering, beam losses in critical regions and radiation load. The experiment will be performed in the CERN-SPS in storage mode with a low intensity 120 GeV/c proton beam. The beam will be perturbed to create a diffusive halo as in the RD22 experiment. The setup consists of four stations. The crystal station contains two goniometers for crystals. The first tracking station houses silicon strip detectors for single particle tracking. The second tracking station contains the same kind of detectors for tracking. The two stations will allow to measure x-x' densities and collimation efficiencies with high precision. The TAL station, at 90 degrees phase advance,is a 600 mm long tungsten secondary collimator. The observables of the experiment are the collimation efficiencies, the measurement of the phase space and the cleaning efficiency deduced from the losses along the ring. We present here the layout of the experiment and the way we expect to collect data in 2009.
ORNL, Oak Ridge, Tennessee
Funding: SNS is managed by UT-Battelle, LLC, for the U.S. DOE under contract DE-AC05-00OR22725
As the SNS beam power is increased, the collimator systems are becoming correspondingly more important. The High Energy Beam Transport (HEBT) transverse collimators are now routinely used during neutron production. We are in the process of redesigning the HEBT momentum collimation system due to problems with gas production from radiolysis. The Ring collimators are designed for two-stage operation but to date they are mainly used in one-stage mode. In this paper we will discuss the status, the operational performance, and upgrades to the collimation systems.
SLAC, Menlo Park, California
CERN, Geneva
Fermilab, Batavia
Funding: Work supported in part by the U.S. Department of Energy contract DE-AC02-76SF00515
It has been proposed to use a hollow electron lens with the LHC beam collimation system*. The hollow electron beam would be used as a beam scraper and positioned at a closer σ than the primary collimators to increase the halo particle diffusion rate striking the primaries. In this paper we use multi-turn beam tracking simulations to analyze the effectiveness of such a lens when integrated into the LHC collimation system.
*Shiltsez, V. et al. "LHC Particle Collimation by Hallow Electron Beams," Proceedings EPAC08, MOPC098 (2008)
STFC/RAL, Chilton, Didcot, Oxon
Exeter University, Exeter, Devon
Gericke LTD, Ashton-under-Lyne
This paper proposes a technology based on fluidized powder which could be employed as a high power target (and beam dump), for example in a future Neutrino Factory or Muon Collider. A fluidized powder target is believed to bring together some advantages of both the solid and liquid phase whilst avoiding some of their drawbacks. The current Neutrino Factory and Muon Collider proposals require the use of a high Z target material withstanding beam ionisation heating of around 1 MW. The article proposes to use a dense tungsten powder jet as an alternative to the baseline open mercury jet for interaction with the proton beam inside the high field capture solenoid. The preliminary experimental results on the production and on the characteristics of a dense horizontal tungsten powder jet are presented. The morphology of the jet is analysed and presented as a function of the driving parameters (e.g. pneumatic supply pressure, boundary conditions of the jet, etc.). A test rig was developed to investigate the reliability of lean and dense phase pneumatic conveying of tungsten powder and the results of such experiments are discussed in the paper.
STFC/RAL, Chilton, Didcot, Oxon
Kyoto University, Kyoto
KEK, Ibaraki
Funding: Science and Technology Facilities Council
The T2K experiment will utilise the highest pulsed power proton beam ever built to generate an intense beam of neutrinos. This uses the conventional technique of colliding the 0.75 MW 30 GeV proton beam with a graphite target and using a magnetic horn system to collect pions of one charge and focus them into a decay volume where the neutrino beam is produced. The target is a two interaction length (900 mm long) graphite target supported directly within the bore of the first magnetic horn which generates the required field with a pulsed current of 300 kA. This paper describes the design and development of the target system required to meet the demanding requirements of the T2K facility. Challenges include radiation damage, shock waves resulting from a 100 K temperature rise in the graphite material during each beam spill, design and optimisation of the helium coolant flow, and integration with the pulsed magnetic horn. Conceptual and detailed engineering studies were required to develop a target system that could satisfy these requirements and could also be replaced remotely in the event of a target failure.
STFC/RAL, Chilton, Didcot, Oxon
KEK, Ibaraki
The target station of the T2K neutrino facility requires a beam window to separate the target chamber, containing helium at atmospheric pressure, from the secondary beam line, which is maintained at ultra high vacuum. In addition to withstanding this differential pressure, the window must survive induced stresses due to intense heating resulting from interaction with a 0.75 MW pulsed proton beam. The design consists of a hemispherical double window with forced convection helium cooling in the volume enclosed, manufactured from titanium alloy. Preliminary analysis suggested that 'shock' waves induced by the pulsed nature of the beam will form the dominant mode of stress. The finite element software ANSYS Mechanical (V10) has been used to simulate the effect of beam impingement on a variety of window thicknesses in an attempt to find the optimum geometry. Results have shown that through thickness stress waves can be amplified if successive bunches arrive in phase with the waves generated by previous bunches. Therefore, thickness has been shown to be a critical variable in determining the window’s resistance to induced thermal shock.
Sheffield University, Sheffield
University of Warwick, Coventry
STFC/RAL/ISIS, Chilton, Didcot, Oxon
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
STFC/RAL, Chilton, Didcot, Oxon
Funding: Science and Technology Facilities Council (United Kingdom)
The UK programme of high power target developments for a Neutrino Factory is centred on the study of high-Z materials (tungsten, tantalum). A description of lifetime shock tests on candidate materials is given as a part of the research into a solid target solution. A fast high current pulse is applied to a thin wire of the sample material and the lifetime measured from the number of pulses before failure. These measurements are made at temperatures up to ~2000 K. The stress on the wire is calculated using the LS-DYNA code and compared to the stress expected in the real Neutrino Factory target. It has been found that tantalum is too weak at these temperatures but a tungsten wire has reached over 26 million pulses (equivalent to more than ten years of operation at the Neutrino Factory). Measurements of the surface velocity of the wire using a laser interferometry system (VISAR) are in progress, which, combined with LS-DYNA modelling, will allow the evaluation of the constitutive equations of the material. An account is given of the optimisation of secondary pion production and capture in a Neutrino Factory and of the latest solid target engineering ideas.
Sheffield University, Sheffield
The MICE experiment requires a beam of low energy muons to test muon cooling. This beam is derived parasitically from the ISIS accelerator at the Rutherford Appleton Laboratory. A novel target mechanism has been developed which allows the insertion of a small titanium target into the proton beam on demand, for the final couple of milliseconds before extraction. The first operational linear drive was installed onto ISIS in January of 2008. Since then, it has operated for over 100,000 actuations. Studies have been performed of particle production and collection by the MICE beam-line, as well as verification of the reliability of the target drive itself. The target data acquisition system records not only the position of the target throughout the ISIS acceleration cycle, but also the outputs from beam loss monitors placed around the synchrotron. Data will be presented showing the stability of the target’s motion and the correlation of beam loss and particle production with the timing and depth of the target’s intersection with the circulating beam.
Sheffield University, Sheffield
The MICE Experiment requires a beam of low energy muons to demonstrate muon cooling. This beam is derived parasitically from the ISIS accelerator. A novel target mechanism has been developed that inserts a small titanium target into the proton beam on demand. The target remains outside the beam envelope during acceleration and then overtakes the shrinking beam envelope to enter the proton beam during the last 2 ms before beam extraction. The technical specifications for the target mechanism are demanding, requiring large accelerations and precise and reproducible location of the target each cycle. The mechanism operates in a high radiation environment, and the moving parts are compatible with the stringent requirements of the accelerator’s vacuum system. This paper will describe the design of the MICE target and how it is able to achieve its required acceleration whilst still meeting all of the necessary requirements for operation within the ISIS vacuum. The first operational linear electromagnetic drive was installed onto ISIS in January 2008 and has since been operated for over one hundred thousand actuations.
UNIFE, Ferrara
INFN-Ferrara, Ferrara
Channeling in bent crystals is a technique with high potential to steer charged-particle beams for several applications in accelerators physics. Channeling and related techniques underwent significant progress in the last years. Distinctive features of performance increase was the availability of novel ideas other than new techniques to manufacture the crystal for channeling. We show the technology to fabricate crystals through non conventional silicon micromachining techniques. Characterization of the realized crystals highlighted that the crystals are free of lattice damage induced by the preparation. The crystals were positively tested at the external line H8 of the SPS with 400 GeV protons for investigation on planar and axial channelings as well as on single and multiple volume reflection experiments by the H8-RD22 collaboration. Selected single- and multi-crystal are candidates for the experiment UA9–an experiment on beam collimation at the CERN SPS.
CERN, Geneva
Beam losses in high-energy particle accelerators are responsible for beam lifetime degradation. In the LHC beam losses will create a shower of particles while interacting with materials from the beam pipes and surroundings, resulting in a partial activation of material in the tunnel. Efforts have been made during the accelerator design to monitor and to reduce the activation induced by beam losses. Traceability for all vacuum components has been established providing a tool to follow-up individually each component or subcomponents installed in the tunnel, regardless of their future destination e.g. recycling or disposal. In the latter case, the history of vacuum components will allow calculating the beam-induced activation and permit comparisons with in-situ and ex-situ measurements. This zoning will also help to reduce collective and individual radiation doses to personnel during interventions. The paper presents the vacuum system layout and describes the LHC vacuum zoning and its implementation using an ORACLE© database.
PAL, Pohang, Kyungbuk
KAERI, Daejon
Funding: Work supported by PEFP and MEST in Korea
The objectives of the cooling system of Proton Engineering Frontier Project (PEFP) Drift Tube Linac (DTL) operated in combination with the low-level RF system (LLRF) are to regulate the resonant frequency of the drift tube cavities of 350 MHz. To provide an effective means of bringing the PEFP DTL up for a resonance condition within ±5 kHz, the prototype of the cooling system has been designed and fabricated to investigate the performance features for the servo stabilization of the cavity resonant frequency. As a result, it is estimated that the resonant frequency could be regulated less than ±1 kHz with this proposed feedback temperature controlled cooling system although introducing a little nonlinear features as the reference operating temperature changes. This report describes the design and performance test results of a cooling system, including the size of water pumping skid components and the temperature control scheme.
Imperial College of Science and Technology, Department of Physics, London
Fermilab, Batavia
The International Design Study for the Neutrino Factory (IDS-NF), which is being carried out by personnel from the Americas, Asia, and Europe, has been established by the Neutrino Factory community to deliver a Reference Design Report for the facility by 2012*. The baseline design, developed from that defined in the ISS**, will provide 1021 muon decays per year from 25GeV stored muon beams. The facility will serve two neutrino detectors; one situated at source-detector distance of between 3000-5000km, the second at 7000-8000km. Muon storage rings have also been proposed as the basis of a multi-TeV lepton-antilepton Muon Collider. The R&D required to deliver the Neutrino Factory and that required to realise the Muon Collider have many synergies including: the pion-production target; ionisation cooling; rapid acceleration of large emittance beams; and the provision of high-gradient accelerating cavities that operate in high magnetic fields. The conceptual design of the accelerator facility for the Neutrino Factory and the relation of the IDS-NF to the EUROnu Design Study will be described***.
*The decision point identified by the Strategy Group of the CERN Council.
**The International Scoping Study for a future Neutrino Factory and super-beam facility.
***Submitted on behalf of the IDS-NF.
UNIFE, Ferrara
IHEP Protvino, Protvino, Moscow Region
INFN-PG, Perugia
Università dell'Insubria & INFN Milano Bicocca, Como
INFN-Roma, Roma
INFN/LNL, Legnaro (PD)
PNPI, Gatchina, Leningrad District
JINR, Dubna, Moscow Region
Università di Roma I La Sapienza, Roma
INFN-Ferrara, Ferrara
CERN, Geneva
INFN-Trieste, Trieste
The H8RD22 collaboration has accomplished an extensive study of axial channeling in the external lines of the CERN SPS. For 400 GeV protons, it was recorded deflection by about 90% of the particles by a short crystal, by far exceeding the performance of previous experiments. Axial channeling with 150 GeV negative hadrons was also firmly observed with deflection capability comparable to the case of positive particles. Near-axis effect such as multiple-volume reflections in a single crystal as a result of the superposition of volume reflections by a series of parallel planes sharing the same axis was investigated with 400 GeV protons. Confirmation of theoretical expectation was observed, in particular most of the particles were deflected by about 50 urad, four times the deflection angle imparted by a single volume reflection of most efficient planes. In this case the angular acceptance was sensitively broader than for the case of channeling. In summary, channeling in axial mode and multi-volume reflections were proven to be two mechanisms for manipulation steering of high-energy particle beams, which side most established techniques such as planar channeling and volume reflection.*
*Contribution on behalf of the H8RD22 collaboration.
Yale University, Beam Physics Laboratory, New Haven, Connecticut
Yale University, Physics Department, New Haven, CT
Omega-P, Inc., New Haven, Connecticut
Fermilab, Batavia
Funding: Supported by US Department of Energy, Office of High Energy Physics
A detailed analysis is presented of a new concept for a high current, high gradient proton beam accelerator in a normal conducting (i.e. room temperature) structure. The structure consists of a cascade of RF cavities in a nearly uniform magnetic axial field. The proton energy gain mechanism relies upon cyclotron resonance acceleration in each cavity. In order to check the concept and determine its limits, an engineering design is presented of a four cavity electron counterpart test accelerator under construction that will mimic parameters of the multi-cavity proton accelerator.
POSTECH, Pohang, Kyungbuk
Funding: Work supported by MEST and PAL.
Recently the Korean government successfully completed a large-scale facility, called the KSTAR, a fully superconducting tokamak after joining in the ITER project. It made renewed interests in large-scale scientific facilities to promote basic and applied research capabilities. The next projects include a space project and particle accelerators. The immediate one in accelerator program is the PLS-upgrade, and its budget is now in the congress for FY2009. The others are in the middle of consensus making process: a heavy ion accelerator for rare isotopes and a new synchrotron light source other than the PLS-upgrade and the ongoing proton linac program. This paper will give an overview of the status and prospects of major particle accelerator initiatives in Korea. The paper will also include descriptions of the significant contributions undertaken by Korea through collaborations with major international facilities using particle accelerators. Finally, the paper will outline how industry, government and universities in Korea are collaborating on particle accelerator R&D.
LLNL, Livermore, California
TomoTherapy, Madison
TPL, Albuquerque, NM
CPAC, Madison
Funding: This work performed under the auspices of the U.S. Department of Energy by Lawrence Livvermore National Laboratory under Contract DE-AC52-07NA27344.
The dielectric wall accelerator* (DWA) system being developed at the Lawrence Livermore National Laboratory (LLNL) uses fast switched high voltage transmission lines to generate pulsed electric fields on the inside of a high gradient insulating (HGI) acceleration tube. High electric field gradients are achieved by the use of alternating insulators and conductors and short pulse times. The system is capable of accelerating any charge to mass ratio particle. Applications of high gradient proton and electron versions of this accelerator will be discussed. The status of the developmental new technologies that make the compact system possible will be reviewed. These include high gradient vacuum insulators, solid dielectric materials, photoconductive switches and compact proton sources.
*Patents pending.
HIT, Heidelberg
The Heidelberg Ion Therapy facility (HIT) is the first dedicated proton and carbon therapy facility in Europe. HIT will start treating the first patients by the end of 2008. The talk presents the commissioning experience and reports on the quality of machine operations in the clinical environment including initial treatment results. The commissioning of the Italian facility Centro Nazionale di Adroterapia Oncologica (CNAO) is also discussed.
JAI, Oxford
Imperial College of Science and Technology, Department of Physics, London
UMAN, Manchester
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
STFC/DL, Daresbury, Warrington, Cheshire
STFC/RAL, Chilton, Didcot, Oxon
Brunel University, Middlesex
GIROB, Oxford
Fermilab, Batavia
Gray Institute for Radiation Oncology and Biology, Oxford
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
Cockcroft Institute, Lancaster University, Lancaster
Funding: EPSRC EP/E032869/1
The PAMELA (Particle Accelerator for MEdicaL Applications) project is to design an accelerator for proton and light ion therapy using non-scaling Fixed Field Alternating Gradient (FFAG) accelerators, as part of the CONFORM project, which is also constructing the EMMA electron model of a non-scaling FFAG at Daresbury. This paper presents an overview of the PAMELA design, and a discussion of the design goals and the principles used to arrive at a preliminary specification of the accelerator.
KURRI, Osaka
University of Fukui, Faculty of Engineering, Fukui
Accelerator based neutron source with an internal target (ERIT-emittance recovery internal target) placed into the proton storage ring has been developed. In this scheme, the beam and energy degradation caused by the target are cured by ionization cooling and the thermal and epi-thermal neutron flux of more than 1x109 n/cm2/sec can be obtained. The experimental results will be given in the conference.
LULI, Palaiseau
INRS-EMT, Varennes (Québec)
Osaka University, Graduate School of Engineering, Osaka
Beam optimization of laser-accelerated protons is a crucial point for the development of applications in various areas. Several directions need to be pursued, namely (i) optimization of the high-energy end of the spectrum e.g. for dense plasma radiography, and (ii) enhancement of laser-to-protons conversion efficiency and reduction of divergence e.g. for fast ignition. We will present recent experimental results and simulations on these topics. We will show that high-energy protons in the TNSA regime could be enhanced using low-density plasmas [2] or reduced mass solid targets [3]. The laser-to-protons conversion efficiency is equally sensitive to laser and target parameters and can be increased using ultra-thin targets [4] or reduced mass solid targets [3]. In addition, we will present some results in exploring radiation-pressure acceleration of ions using circularly polarized laser pulses.
[3] S. Buffechoux et al., “Enhanced laser acceleration of protons from reduced mass targets”, in preparation
[4] P. Antici, J. Fuchs et al., IEEE Trans. On Plasma Sci. 36, 1817 - 1820 (2008).
BNL, Upton, Long Island, New York
In this report we summarize electron-cloud simulations for the RHIC dipole regions at injection and transition to estimate if scrubbing at injection would reduce the electron cloud density at transition. We simulate the horizontal electron cloud distribution in the RHIC dipoles for secondary electron yields (SEY) from 1.1 to 2.0 at injection (with a bunch intensity of 1.3x109) and at transition (with a bunch intensity of 1.2x109). Also, we unveil the sensitivity to rather small changes in bunch intensity from 1.0 x109 to 1.5x109 , when SEY keep at 1.4 and 1.5 both for injection and transition.
Enrico Fermi Institute, University of Chicago, Chicago, Illinois
Fermilab, Batavia
Understanding beam loss in an accelerator is crucial to accelerator design and operation. Losses contribute to a shorter lifetime of a circulating beam, higher radiation doses to accelerator components, and backgrounds in experiments which use the beam. One source of beam loss is diffusion caused by effects such as beam scattering with residual gas in vacuum chamber, noise in the radio frequency acceleration system and power supplies, and beam-beam collisions. We measure the diffusion rate in the Fermilab Tevatron using the flying wire beam profile monitor. We have developed a new technique for interpreting the flying wire data. Using this technique, we measure the proton horizontal diffusion rate for ten stores in the Tevatron during colliding beam operation.
CERN, Geneva
SLAC, Menlo Park, California
The LHC collimation system is implemented in phases, in view of the required extrapolation by 2-3 orders of magnitude beyond Tevatron and HERA experience in stored energy. All available simulations predict that the LHC proton beam intensity with the "phase 1" collimation system may be limited by the impedance of the collimators or cleaning efficiency. Maximum efficiency requires collimator materials very close to the beam, generating the dominant resistive impedance in the LHC. Above a certain intensity the beam is unstable. On the other hand, even if collimators are set very close to the beam, the achievable cleaning efficiency is predicted to be inadequate, requiring either beam stability beyond specifications or reduced intensity. The accelerator physics concept for upgrading cleaning efficiency, for both proton and heavy ion beams, and reducing collimator-related impedance is described. Besides the "phase 2" secondary collimators, new collimators are required in a few super-conducting regions.
CERN, Geneva
Collimation and halo cleaning for the LHC beams are performed separately for betatron and momentum losses, requiring two dedicated insertions for collimation. Betatron cleaning is performed in IR7 while momentum cleaning is performed in IR3. A study has been performed to evaluate the performance reach for a combined betatron and momentum cleaning system in IR3. The results are presented.
CERN, Geneva
IHEP Protvino, Protvino, Moscow Region
We report on background studies for the LHC with detailed simulations. The simulations now include generation of beam-gas scattering in combination with multiturn tracking of protons. Low beta optics and available aperture files for this configuration have been used to generate loss maps according to the pressure distribution in the LHC.
CERN, Geneva
The usual approach and treatment for the interaction of a particle beam with wake fields start from the assumption of ultrarelativistic beams. This is not the case, for example, for the Proton Synchrotron Booster (PSB) whose particles have a kinetic energy up to 1.4 GeV, with a relativistic gamma close to 2.5. There are some examples in literature which derive non ultrarelativistic formulas for the resistive wall impedance. In this paper we have extended the Broad-Band resonator model, allowing the impedance to have poles even in the half upper complex plane, in order to obtain a wake function different from zero for z greater than zero. The Haissinski equation has been numerically solved showing longitudinal bunch shape changes with the energy. In addition some longitudinal bunch profile measurements, taken for different energies and bunch intensities at the PSB, are shown.
CERN, Geneva
The usual approach for the resistive pipe wall assumes the beam moves with the speed of light. For many low energy rings, such as the Proton Synchrotron Booster (PBS), possible performance limitations may arise from non relativistic resistive wall wake fields. In this regime not only the head of the bunch can interact with the tail but also the vice versa holds. In this paper we analyze numerical results showing the resistive wake field calculated from non relativistic impedance models. In addition we analyze the well known two particles model assuming that even the trailing particle can affect the leading one. We observe significant changes in the stability domain.
Fermilab, Batavia
The proposed Mu2e experiment will present a number of challenges for the Fermilab accelerator complex. The Accumulator and Debuncher rings of what is currently the antiproton complex will be required to handle proton beams with intensities several orders of magnitude larger than the antiproton beams they now carry, leading to a substantial space-charge tune shift. The protons will be then be extracted from the Debuncher using resonant extraction. We present results from simulations of 3D space charge effects for Mu2e beam parameters, with emphasis on how they affect the resonant extraction process.
Fermilab, Batavia
Tech-X, Boulder, Colorado
Simulation of the microwave transmission properties through the electron cloud at the Fermilab Main Injector have been implemented using the plasma simulation code ‘‘VORPAL". Phase shifts and attenuation curves have been calculated for the lowest frequency TE mode, slightly above the cutoff frequency, in field free regions, in the dipoles and quadrupoles. Preliminary comparisons with experimental results are discussed and will guide the next generation of experiments.
Fermilab, Batavia
FZJ, Jülich
BINP SB RAS, Novosibirsk
We report preliminary results of experimental studies of "electron columns" in the Tevatron and in a specialized test setup. In the Tebvatron, 150 GeV beam of protons ionized residual gas and ionization electrons are stored in an electrostatic trap immersed into strong longitudinal magnetic field. Shifts of proton betatron frequencies are reported. In the test set, we observe effects pointing to accumulation and escape of ionization electrons.
LBNL, Berkeley, California
Fermilab, Batavia
Funding: Supported by the US DOE under contract DE-AC02-05CH11231 and by the Fermilab Main Injector upgrade effort.
We provide a brief status report on measurements and simulations of the electron-cloud in the Fermilab Main Injector. Areas of agreement and disagreement are spelled out, along with their possible significance.
ANL, Argonne
Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.
Kinetic space plasma simulations are dominated by PIC (Particle-In-Cell) codes. Due to the inherent noise in PIC simulations, interest in directly solving the Vlasov equation is increasing. With the fast development of supercomputers, this is becoming more realistic. We present our preliminary work on solving the Vlasov equation for beam dynamics simulations*. A high order Spectral Element Method has been applied to achieve high accuracy, easy interpolation, and parallelization. Due to the inherent instability of the Vlasov equation, a spectral filter has been added and mass conservation has been satisfied. The proposed algorithms were validated on 1D1V simulations. A paraxial model of the Vlasov equation (2D2V) has also been studied and compared with PIC simulations at ANL using the BG/P supercomputer.
*J. Xu, P. Ostroumov and J. Nolen, “Highly Scalable Parallel Algorithm for 2D2V Vlasov Equation with High Order Spectral Element Method”, poster on SC08, Austin, Texas, Nov.15-20, 2008.
IHEP Beijing, Beijing
The electron proton (e-p) instability has been observed in many proton accelerators. It will induce transverse beam size blow up, cause beam loss and restrict the machine performance. A simulation code is developed to study the electron proton instability in the China Spallation Neutron Source (CSNS) ring. The results of numerical simulation of the electron cloud formation and the electron proton instability are presented.
G.H. Gillespie Associates, Inc., Del Mar, California
A PARMILA 2 Module has been developed for the Particle Beam Optics Laboratory (PBO Lab). PARMILA 2 is a FORTRAN program used to both design and simulate radiofrequency ion linear accelerators. The program can be used to design radiofrequency accelerators that include drift tube linac (DTL) structures, coupled cavity linac (CCL) structures, coupled-cavity drift tube linac (CC-DTL) structures, and superconducting accelerator structures. PARMILA 2 can also be used to simulate beams in these structures and in transport lines that with magnetic, radiofrequency and electrostatic beam optics elements. PBO Lab provides a sophisticated graphic user interface (GUI) for multiple optics codes. From the same familiar interface users can run TRANSPORT, TURTLE, MARYLIE, TRACE 3-D and DECAY-TURTLE. PARMILA 2 now joins this suite of optics codes available as PBO Lab Modules. New PBO Lab tools have been developed to assist users in utilizing different optics codes to simulate and validate the performance of an accelerator designed with PARMILA 2. An overview of the new PARMILA 2 module and associated new tools is presented and some of the GUI features are illustrated.
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
KEK/JAEA, Ibaraki-Ken
In order to observe two-dimensional beam profiles in the longitudinal phase space, the reconstruction techniques with the computer tomography algorithms can be adopted at the J-PARC RCS. On the assumption that the longitudinal profiles should not be disturbed for one period of the synchrotron oscillation, such two-dimensional profiles can be reconstructed easily from one-dimensional bunch beam profiles, which are measured for every turn by the wall current monitor. In this presentation, we introduce the experimental results and the comparison to the longitudinal beam tracking simulation, and we discuss the technical issues and applicability of this longitudinal tomography techniques.
Muons, Inc, Batavia
BNL, Upton, Long Island, New York
Funding: Work supported in part by USDOE STTR Grant DE-FG02-08ER86281 and DE AC02 98CH10886.
The U.S. muon collider community is mobilizing itself to produce a “Design Feasibility Study” (DFS) for a muon collider. This is happening on an aggressive schedule and must include the best possible simulations to support and validate the technical design. The DFS for a muon collider will require innovative new approaches to many aspects of accelerator design, and the simulations to support it will require tools with features and capabilities that are equally innovative and new. Two computer programs have emerged as the preferred and most commonly used simulation tools within the muon collider community: ICOOL (primary author: Dr. Fernow), and G4beamline (primary author: Dr. Roberts). We describe the ongoing development and testing of both tools for the DFS, including a common suite of tests to ensure that both tools give accurate and realistic results, as well as innovative user-friendly interfaces with emphasis on graphical user interfaces and windows.
ANL, Argonne
Euclid TechLabs, LLC, Solon, Ohio
PSU, University Park, Pennsylvania
Saint-Petersburg State University, Saint-Petersburg
Funding: DOE
Metamaterials (MTMs) are periodic artificially constructed electromagnetic structures. The periodicity of the MTM is much smaller than the wavelength of the radiation being transported. With this condition satisfied, MTMs can be assigned an effective permittivity and permeability. Areas of possible application of MTMs in accelerator science are Cherenkov detectors and wakefield devices. MTMs can be designed to be anisotropic and dispersive. The combination of engineered anisotropy and dispersion can produce a Cherenkov radiation spectrum with a different dependence on particle energy than conventional materials. This can be a basis for novel non-invasive beam energy measurements. We report on progress in the development of these media for a proof-of-principle demonstration of a metamaterial-based beam diagnostic.
BNL, Upton, Long Island, New York
Fermilab, Batavia
Funding: Work performed under the auspices of the US Department of Energy
SiO2 quartz fibers of the LHC ATLAS 0-degree calorimeter (ZDC) anticipated to experience integrated doses of a few Grad at their closest position were exposed to 200 MeV protons and neutrons at the BNL Linac. Specifically, 1mm- and 2mm- diameter quartz (GE 124) rods were exposed to direct 200 MeV protons during the first phase of exposure leading to peak integrated dose of ~28 Grad. Exposure to a primarily neutron flux of 1mm-diameter SiO2 fibers was also achieved with a special neutron source arrangement. In a post-irradiation analysis the quartz fiber transmittance was evaluated as a function of the absorbed dose. Dramatic degradation of the transmittance property was observed with increased radiation damage. In addition, detailed evaluation of the fibers under the microscope revealed interesting micro-structural damage features and irradiation-induced defects. This paper presents the results of the irradiation damage study.
BNL, Upton, Long Island, New York
The effects of high fluences of energetic charged particles on CdZnTe detectors have been studied and are reported in this paper. Specifically, 200 MeV protons of the Brookhaven National Laboratory LINAC were used to bombard a set of CdZnTe detector crystals to fluences as high as 2.6x1016 protons/cm2. Following exposure a set of past-irradiation analyses were conducted to quantify the effects. These include (a) gamma-ray spectra analysis using a high-purity germanium detector in an effort to assess both the peak position shifting as a function of fluence and the spectral content, (a) resistivity and leakage current measurements, and (c) manifestation of radiation damage in the crystal microstructure. In addition, and based on the irradiation parameters used, a numerical prediction model was formulated aiming to benchmark the observed isotopes.
BNL, Upton, Long Island, New York
A gas fluorescence beam profile monitor has been realized at the relativistic heavy ion collider (RHIC) using the polarized atomic hydrogen gas jet. RHIC proton beam profiles in the vertical plane are obtained as well as measurements of the width of the gas jet in the beam direction. For gold ion beams, the fluorescence cross section is sufficiently large so that profiles can be obtained from the residual gas alone, albeit with long light integration times and lower number of Au ions than protons. We estimate the fluorescence cross-section of 100 GeV protons and Au ions on hydrogen gas to be 6.6x10-21 cm2 ~1.7x10-16 cm2, respectively*. We calculate the beam emittance to provide an independent measurement of the RHIC beam. This optical beam diagnostic technique, utilizing the beam induced fluorescence from injected or residual gas, represents a step towards the realization of a simple and truly noninvasive beam monitor for high-energy particle beams together with a wall-current-monitor system and/or a low light level optical temporal measurement system, a 3-dimensional particle beam profile system can be envisioned providing routine diagnosis of high-energy particle beams.
*T. Tsang, et. al., Rev. Sci. Instrum. 79, 105103 (2008).
BNL, Upton, Long Island, New York
Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
The proton polarization measurements in AGS and RHIC are based on proton-carbon and proton-proton elastic scattering in the Coulomb Nuclear Interference region. Polarimeter operation in the scanning mode gives polarization profiles and beam intensity profile measurements. This polarimeter is an ideal wire-scanner due to: extremely good signal/noise ratio and high counting rate, which allows accurate bunch by bunch emittance measurements during 100 ms time of the beam crossing. The measurements of the beam emittance in both vertical and horizontal planes will be possible after polarimeter upgrade for the 2009 polarized run. Two new vacuum chambers and two target motion mechanisms and detectors assembly will be installed in each ring. One polarimeter can be used for the vertical polarization and intensity profile measurements and the second can be used for the horizontal profile measurements. The absolute accuracy limitations and cross-calibration of different techniques will be also discussed.
IHEP Beijing, Beijing
A set of IPM system will be built on RCS of CSNS to measure vertical and horizontal beam profiles. Detailed conceptual design of an IPM system for CSNS is described in this paper. Wire electrodes are introduced to get a more uniform electric field, and a ‘C’ type electromagnet is designed to exert a uniform magnetic field to the ionization area. The magnetic field is parallel with the sweeping electric field and will inhibit the defocusing effects of space charge and recoil momentum.
CERN, Geneva
The TOTEM experiment at the LHC will operate at down to 10 σ from the beam in the forward region of the CMS experiment. The associated beam loss monitors (BLMs) are crucial to monitor the position of the detectors and to provide a rapid identification of abnormal beam conditions for machine protection purposes. In this paper, the response of the TOTEM BLMs is considered and the protection thresholds are defined, with calculations made of the expected signal from protons grazing the TOTEM pot as a function of pot distance from the beam, and of the BLM signal from proton collisions at the CMS beam interaction point.
CERN, Geneva
The LHC collision rate monitors (BRAN) will be used to monitor and optimize the luminosity at the four interaction points (IP). Depending on the expected level of luminosity for a given IP two different designs have been developed for LHC. At IP1 and IP5, the high luminosity experiments, the BRAN consist of fast ionization chambers and at IP2 and IP8, where the collision rate will be smaller, they consist of fast polycristalline-CdTe detectors. A better understanding of the performances of those detectors can be provided by detailed tracking simulations of the collision products coming from the IP within the detector. Here we report about the results of simulations done with FLUKA as well as a comparison with measurements done in the SPS.
CERN, Geneva
Poznań University of Technology, Poznań
The LHC beam loss monitoring system (BLM) consists of about 4000 monitors observing losses at all quadrupole magnets and many other likely loss locations. At the first LHC operation in August and September 2008 all monitors were active and used to observe the losses during the initial beam steerings, at collimators, at the LHC dump and during aperture scans. The different loss patterns will be discussed and compared with the expectations originating from simulations. The observed signals of the BLM system will be analysed in terms of response time, sensitivity cross talk between channels and noise performance.
CERN, Geneva
The LHC collimators are protected against beam caused damages by measuring the secondary particle showers with beam loss monitors. Downstream of every collimator an ionisation chamber and a secondary emission monitor are installed to determine the energy deposition in the collimator. The relation between the energy deposition in the beam loss monitor and the collimator jaw is based on secondary shower simulations. To verify the FLUKA simulations the prototype LHC collimator installed in the SPS was equipped with beam loss monitors. The results of the measurements of the direct impact of the 26 GeV proton beam injected in the SPS onto the collimator are compared with the predictions of the FLUKA simulations. In addition simulation results from parameter scans and for mean and peak energy deposition with its dependencies are shown.
Fermilab, Batavia
Funding: Operated by Fermi Research Alliance, LLC under Contract No. DE-AC02-07CH11359 with the United States Department of Energy.
We have designed a retarding field analyzer (RFA) and a rad-hard amplifier which improves the sensitivity over the present RFA installed in the Main Injector. From computer simulations and bench measurements, our RFA will have a 20% improvement in sensitivity compared to the Argonne National Laboratory (ANL) design. And when we couple our RFA to the matched rad-hard amplifier, S/N is also improved.
DPNC, Genève
The MICE experiment aims at demonstrating that the performances of the muon ionization technique are compatible with the requirements of the neutrino factory and the muon collider. The experiment is running at the Rutherford-Appleton Laboratory in the UK using the ISIS proton beam on a dynamic target as a muon source. Brand new target system and muon beam line have been designed, built and installed during the last two years. On the other hand, particle identification detectors needed for the experiment have also been installed and commissioned. This presentation describes how we made use of Time of Flight detectors, aerogel Cherenkov counters and electro-magnetic calorimeter sensors to characterize the content of the MICE beam between 100 and 480 MeV/c.
KEK, Ibaraki
Osaka University, Osaka
Proton beam extinction, defined as a ratio of the residual and the pulse beam intensity, should be less than 10-9, which is one of the key requirements to realize the future muon electron conversion experiment (COMET) proposed at J-PARC. Measurement of the pulse timing structure with enough sensitivity is the first step to achieve the required extinction level. We have developed two methods for the measurements; one by using fast-extracted beam and the other by using slow-resonant-extracted beam. This paper describes the schemes and the results of the measurements*. These measurements would provide important information on the beam pulse structure to understand not only for MR beam but also the whole accelelator complex, including LINAC and booster RCS.
*Submitted on behalf of the muon working group
IUCF, Bloomington, Indiana
Fermilab, Batavia
The proton ion source for the High Intensity Neutrino Source (HINS) Linac front-end at Fermilab has been successfully commissioned. It produces a 50 keV, 3 msec beam pulse with a peak current greater than 20 mA at 2.5 Hz. The beam is transported to the radio-frequency quadrupole (RFQ) by a low energy beam transport (LEBT) that consists of two focusing solenoids, four steering dipole magnets and a beam current transformer. To understand beam transmission through the RFQ, it is important to characterize the 50 keV beam before connecting the LEBT to the RFQ. A wire scanner and a Faraday cup are temporarily installed at the exit of the LEBT to study the beam parameters. Beam profile measurements are made for different LEBT settings and results are compared to those from computer simulations. In lieu of direct emittance measurements, a solenoid variation method based on profile measurements is used to reconstruct the beam emittance.
Institute of High Energy Physics, CAS, Bejing
IHEP Beijing, Beijing
A high current proton RFQ accelerator has been constructed in China for the basic study of Accelerator Driven Subcritical System. A new beam line will be set up for the 3.54MeV, 50mA proton beam from the RFQ in order to study beam halo phenomenon. Therefore, 18 wire scanners consist of a thin carbon wire and two scrapers will be installed on the beam line to traverse the entire beam cross-section. So we can experimentally study the beam loss and beam halo. Some simulations results of the heat on the devices by using finite element method software–ANSYS are presented. The electronics interface will also be discussed.
LBNL, Berkeley, California
CERN, Geneva
BNL, Upton, Long Island, New York
The Luminosity Monitor for the LHC has been built at LBL and is going to be installed in the LHC in early 2009. The device designed for the high luminosity regions (ATLAS and CMS) is a gas ionization chamber, that is designed with the ability to resolve bunch by bunch luminosity as well as survive extreme levels of radiation. During the experimental R&D phase of its design, the prototype of this detector has been tested extensively in RHIC as well as in the SPS. Result of these experiments are shown here, with comments on the implications for early operations of the LHC.
LANL, Los Alamos, New Mexico
Funding: This work is supported by the United States Department of Energy under contract DE-AC52-06NA25396
Precise measurement of the tunes in the Los Alamos Proton Storage Ring (PSR) is difficult because the beam is normally extracted immediately after accumulation, preventing the use of continuous-wave radio frequency measurements. Presented here is a method that takes advantage of the phase information in the response of the beam to a transverse oscillatory driving voltage. This technique offers much greater precision than using the amplitude spectrum alone.
CAEP/IFP, Mainyang, Sichuan
The capability of the chromatic correction of Zumbro Lens lies on the angle-position correlation, which is obtained by passing the beam through an expander or quadruples. However even after a long distance drift downstream the expander, the angle-position correlation can not be perfect because of the existence of finite emittance. This paper discusses the influence of the emittance to the chromatic correction and the optimization of beam status in phase space at the entrance of the expander.
CERN, Geneva
The LHC phase II collimation project requires beam shock and impact tests of materials used for beam intercepting devices. Similar tests are also of great interest for other accelerator components such as beam entrance/exit windows and protection devices. For this purpose a dedicated High Radiation Material test facility (HiRadMat) is under study. This facility may be installed at CERN at the location of a former beam line. This paper describes the associated beam line which is foreseen to deliver a 450 GeV proton beam from SPS with an intensity of up to 3·1013 protons per shot. Different beam line designs will be compared and the choice of the beam steering and diagnostic elements will be discussed, as well as operational issues.
Fermilab, Batavia
Funding: Work supported by the Fermi Research Alliance, LLC under contract No. DE-AC02-07CH11359 with the U.S. Dept. of Energy.
A transition-free lattice is a basic requirement of a high-intensity medium-energy (several GeV) proton synchrotron in order to eliminate beam losses during transition crossing. An 8 GeV synchrotron is proposed as a principal component in an alternative hybrid design of Project-X. This machine would be housed in the Fermilab antiproton source enclosure replacing the present Debuncher. A simple doublet lattice with high transition gamma has been designed. It uses just one type of dipoles and one type of quadrupoles (QF and QD are of the same length). It has no transition crossing. It has a triangular shape with three zero dispersion straight sections, which can be used for injection, extraction, RF and collimators. The beta-functions and dispersion are low. This lattice has plenty of free space for correctors and diagnostic devices, as well as good optical properties including large dynamic aperture, weak dependence of lattice functions on amplitude and momentum deviation.
*W. Chou, “An Alternative Approach to Project X,” this conference.
PSI, Villigen
The Paul Scherrer Institute (PSI) operates a high power proton accelerator for the research projects in physical and medical sciences. Currently, a proton beam current of 2mA with a beam power of 1.2MW is routinely used. In the future, the ring cyclotron with new cavities will make a proton beam current of 3mA possible. The enhanced beam power will generate higher thermal and mechanical loads to different accelerator components. In this paper, a simulation based study of a new current monitor designed to sustain the 3mA beam operation is presented. The monitor is located behind the second graphite target and exposed to scattered particles and their secondaries. The thermal energy deposition in the current monitor has been calculated by the Monte-Carlo particle transport code MARS. The calculated power source has been used for the the coupled flow, heat and radiation simulations, for the prediction of the operating temperature. The effect of the newly introduced water cooling system and the surface blackening has been analyzed by using CFX. The thermal properties of the monitor system have been measured by laboratory experiments, and a simulation validation study is presented.
PSI, Villigen
With increasing beam powers and current densities in current neutron spallation sources one approaches materials' limits. The importance of near-target beam monitoring rises accordingly. At the Paul Scherrer Institute (PSI), the liquid metal target of MEGAPIE set especially stringent requirements for the reliable interruption of the proton beam in case of an anomaly in the incident current density distribution. A completely novel device called VIMOS based on the optical monitoring of a glowing mesh has been devised. By now, the system has been operating successfully for five years. Starting from the initial goal of reliably detecting beam anomalies in a timely manner the scope of the system has been extended to serve as a standard device for beam monitoring and fine tuning of the settings of the beam transport lines. In parallel to the expansion of the use of VIMOS over time, requirements for improving the maintainability of the system while also reducing concurrent cost have become more urgent. A summary of the operational experience of VIMOS will be reported as well as steps taken in order to deliver more quantitative data on the beam profile in the future.
TRIUMF, Vancouver
SFU, Burnaby, BC
UBC, Vancouver, B.C.
Funding: TRIUMF receives funding via a contribution agreement through the National Research Council of Canada.
For ISAC at TRIUMF, radioactive isotopes are generated with a 500MeV proton beam. The beam power is up to 40kW and can easily melt the delicate target if too tightly focused. We protect this target by closely monitoring the distribution of the incident proton beam. There is a 3-wire scanner monitor installed near the target; these give the vertical profile and the +45 and -45 degree profiles. Our objective is to use these 3 measured projections to find the 2-D density distribution. By implementing the maximum entropy (MENT) algorithm, we have developed a computer program to realize tomographic reconstruction of the beam density distribution. Of particular concern is to make the calculation sufficiently efficient that an operator can obtain the distribution within a few seconds of the scan. As well, we have developed the technique to perform phase space reconstruction, using many wire scans and the calculated transfer matrices between them. In this paper we present details of the computer code and the techniques used to improve noise tolerance and compute efficiency.
UW-Madison, Madison, Wisconsin
ORNL, Oak Ridge, Tennessee
Funding: *Work performed under the auspices of ORNL/SNS, ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725
An electron-proton (e-p) instability is observed with increased beam intensity at the Spallation Neutron Source (SNS) in Oak Ridge National Laboratory (ORNL). This paper presents a wide-band, mixed-signal system for active damping of the e-p instability. It describes techniques used for feedback damping, data acquisition, and analysis. The paper also describes analysis strategies to monitor system performance. The mixed-signal feedback damper system includes anti-aliasing low-pass filters, power amplifiers (PAs), analog-to-digital converters (ADCs), reconfigurable field programmable gate array (FPGA) hardware and digital-to-analog converters (DACs). The system will provide feedback damping, system monitoring, and offline analysis capabilities. The digital portion of the system features programmable gains and delays, and equalizers that are implemented using parallel comb filters and finite impulse response (FIR) filters. These components perform timing adjustments, compensate for gain mismatches, correct for ring harmonics, and equalize magnitude and phase dispersions from cables and amplifiers.
BNL, Upton, Long Island, New York
The talk reviews the RHIC performance, including the unprecedented manipulations of polarized beams and the recent low energy operations. Achievements and limiting factors of RHIC operation are discussed, e.g. intrabeam scattering, electron cloud, beam-beam effects, magnet vibrations, and the efficiency of novel countermeasures such as bunched beam stochastic cooling, beam conditioning and chamber coatings. The future upgrade plans and the pertinent R&D program will also be presented.
CERN, Geneva
An LHC high-luminosity upgrade has been studied by various European and international collaborations since about 2001. Ingredients of such an LHC upgrade include the optimization of the IR layout, new high-field or large-aperture triplet quadrupoles, chromatic correction, possibly detector-integrated slim magnets, crab cavities, beam-beam compensators, operation in a regime of large Piwinski angle, luminosity leveling for reduced detector pile up, heat-load, background, and radiation damage due to the collision debris, and a renovation of the injector complex. Scenarios, decision paths, and present R&D efforts will be presented.
Fermilab, Batavia
Funding: Work supported by the United States Department of Energy under Contract No. DE-AC02-07CH11359
Over the past year Tevatron has been routinely operating at initial luminosity over 3·1032. The high luminosity regime highlighted several issues that became the focus for operational improvements. In this report we summarize the experience in such areas as mitigation of particle losses, maintaining orbit and optics stability, and identification of aperture restrictions.
CERN, Geneva
N.U, Nigde
Cockcroft Institute, Warrington, Cheshire
Ankara University, Faculty of Sciences, Tandogan/Ankara
The University of Liverpool, Liverpool
KEK, Ibaraki
TOBB ETU, Ankara
BNL, Upton, Long Island, New York
Sub-atomic physics at the energy frontier probes the structure of the fundamental quanta of the Universe. The Large Hadron Collider (LHC) at CERN opens for the first time the “terascale” (TeV energy scale) to experimental scrutiny, exposing the physics of the Universe at the sub-attometric (~10-19 m, 10-10 as) scale. The LHC will also take the science of nuclear matter to hitherto unparalleled energy densities (low-x physics). The hadron beams, protons or ions, in the LHC underpin this horizon, and also offer new experimental possibilities at this energy scale. A Large Hadron electron Collider, LHeC, in which an electron (positron) beam of energy (70 to 140 GeV) is in collision with one of the LHC hadron beams, makes possible terascale lepton-hadron physics. The LHeC is presently being evaluated in the form of two options, “ring-ring” and “linac-ring”, either of which operate simultaneously with pp or ion-ion collisions in other LHC interaction regions. Each option takes advantage of recent advances in radio-frequency, in linear acceleration, and in other associated technologies, to achieve ep luminosity as large as 1033 cm-2s-1.
BNL, Upton, Long Island, New York
Cooling intense high-energy hadron beams remains a major challenge in modern accelerator physics. Synchrotron radiation is still too feeble, while the efficiency of two other cooling methods, stochastic and electron, falls rapidly either at high bunch intensities (i.e. stochastic of protons) or at high energies (e-cooling). In this talk a specific scheme of a unique cooling technique, Coherent Electron Cooling, will be discussed. The idea of coherent electron cooling using electron beam instabilities was suggested by Derbenev in the early 1980s, but the scheme presented in this talk, with cooling times under an hour for 7 TeV protons in the LHC, would be possible only with present-day accelerator technology. This talk will discuss the principles and the main limitations of the Coherent Electron Cooling process. The talk will describe the main system components, based on a high-gain free electron laser driven by an energy recovery linac, and will present some numerical examples for ions and protons in RHIC and the LHC and for electron-hadron options for these colliders. BNL plans a demonstration of the idea in the near future.
Fermilab, Batavia
Funding: Work supported by the Fermi Research Alliance, under contract to the U. S. Department of Energy
As the Fermilab Collider program draws to a close, a vision has emerged of an experimental program built around the high intensity frontier. The centerpiece of this program will be a new 8 GeV superconducting H- linac which will support world leading programs in long baseline neutrino experimentation and the study of rare processes. Based on technology shared with the International Linear Collider, Project X will support the generation of multi-MW beams at 60-120 GeV from the Main Injector, simultaneous with several hundred kilowatts at 8 GeV from the Recycler. Project X will also open the possibility of a future energy frontier facility based on utilization as the front end of a muon storage ring based facility.
CERN, Geneva
A series of LHC injection tests was performed in August and September 2008. The first saw beam injected into sector 23; the second into sectors 78 and 23; the third into sectors 78-67 and sectors 23-34-45. The fourth, into sectors 23-34-45, was performed the evening before the extended injection test on the 10th September which saw both beams brought around the full circumference of the LHC. The tests enabled the testing and debugging of a number of critical control and hardware systems; testing and validation of instrumentation with beam for the first time; deployment, and validation of a number of measurement procedures. Beam based measurements revealed a number of machine configuration issues that were rapidly resolved. The tests were undoubtedly an essential precursor to the successful start of LHC beam commissioning. This paper provides an outline of preparation for the tests, the machine configuration and summarizes the measurements made and individual system performance.
CERN, Geneva
Fast kicker magnets are used to inject beam into and eject beam out of the CERN SPS accelerator ring. These kickers are generally ferrite loaded transmission line type magnets with a rectangular shaped aperture through which the beam passes. Unless special precautions are taken the impedance of the ferrite yoke can provoke significant beam induced heating, over several hours, even above the Curie temperature of the ferrite. At present the nominal bunch spacing in the SPS is 25 ns, however for an early stage of LHC operation it is preferable to have 50 ns bunch spacing. Machine Development (MD) studies have been carried out with an inter-bunch spacing of 25 ns, 50 ns or 75 ns. For some of the SPS kicker magnets the 75 ns bunch spacing resulted in considerable beam induced heating. In addition the MDs showed that 50 ns bunch spacing could result in a very rapid pressure rise in the kicker magnet and thus cause an interlock. This paper discusses the MD observations of the SPS kickers and analyses the available data to provide explanations for the phenomena: possible remedies are also discussed.
Fermilab, Batavia
Funding: This work was supported by the Fermi National Accelerator Laboratory, which is operated by Universities Research Association, under contract No.DE-AC02-76CH03000 with the U.S. Department of Energy
This talk will present arguments that the Neutrino Factory - an extremely intense source of flavor-tagged neutrinos from muon decays in a storage ring - gives the best physics reach for CP violation, as well as virtually all parameters in the neutrino oscillation parameter space. It will describe the physics capabilities of a baseline Neutrino Factory as compared to other possible future facilities (beta-beam and super-beam facilities), give an overview of the accelerator complex, describe the current international R&D program and present a potential time line for the design and construction of the facility. Although the baseline study focuses on a facility with muon energy of 25 GeV, a concept for a Low-Energy (~ 4 GeV) Neutrino Factory has also been developed and its physics reach will also be discussed. Finally, it will be shown that a facility of this type is unique in that it can present a physics program that can be staged, addressing exciting new physics at each step. Eventually it can lead to an energy-frontier muon collider. A muon accelerator facility is a natural extension that can exploit the high intensity potential at FNAL starting with Project X.
JAI, Oxford
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
PAMELA (Particle Accelerator for MEdicaL Applications) is a design for a non-scaling Fixed Field Alternating Gradient accelerator facility for Charged Particle Therapy, using protons and light ions such as carbon to treat certain types of cancer. A lattice has been designed which constrains the variation of betatron tunes through acceleration and thus avoids integer resonance crossing and beam blow-up. This paper outlines the design and performance of this proposed PAMELA lattice.
SLAC, Menlo Park, California
BNL, Upton, Long Island, New York
Funding: US DOE
Unlike an electron storage ring with radiation damping, resonance excitation is unsuitable to a proton storage ring for turn-by-turn betatron orbit data. However, one may consider modified betatron motion driven by ac dipoles oscillating at frequencies near the betatron tunes. With a matrix formulation for adding ac-dipole effects on 2-D coupled one-turn map, we concatenate the ac-dipole effects and the one-turn map to obtain a modified linear map. The ac-dipole effects are equivalent to inserted symplectic linear maps at the ac-dipole locations. If the maps are normalized through decoupling similarity transformation, the decoupled maps for the ac-dipole effects are equivalent to 1-D thin quads inserted at the corresponding locations, the same conclusion for the 1-D driven oscillation*. For optics modeling with MIA technique**, one must make sure that there are, simultaneously, two transverse ac-dipole driven betatron oscillations along with one longitudinal synchrotron oscillation. Once the optics model for the modified betatron motion is obtained, one can then obtain the proton storage ring model by de-concatenating the inserted ac-dipole linear maps.
* R. Miyamoto, S.E. Kopp, A. Jansson, and M.J. Syphers, PRSTAB 11, 084002 (2008).
** Y.T. Yan, ICFA Beam Dynamics Newsletter, No. 42, pp. 71-87 ( 2007), Y. Cai, W. Chou, Eds.
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
Using an FFAG for rapid-cycling proton acceleration has the advantage that the acceleration cycle is no longer subject to constraints from the main magnet power supply used in an RCS. The RF can be used to its maximum potential to increase the energy range in a short 50Hz cycle as proposed for multi-MW proton driver projects. The challenge becomes an optical one of maintaining a stable lattice across a wide range of beam momenta without magnet sizes or the ring circumference making the machine prohibitively expensive for its purpose. Investigations of stable energy ranges for proton FFAG lattices in the few GeV regime (relativistic but not ultra-relativistic) are presented here.
ORNL, Oak Ridge, Tennessee
IUCF, Bloomington, Indiana
Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.
During one of the high beam intensity runs in SNS, a coasting beam instability was observed in the ring when the beam was stored for 10000 turns. This instability was observed at an intensity of about 12 microcoulombs and was characterized by a frequency spectrum peaking at about 6 MHz. A likely cause of the instability is the impedance of the ring extraction kickers. We carry out here a detailed benchmark of the observed instability, uniting an analysis of the experimental data, a precise ORBIT Code tracking simulation, and a theoretical estimate of the observed beam instability.
CERN, Geneva
MPI-P, München
Short high-energy proton bunches have been proposed as efficient drivers for future single-stage electron-beam plasma accelerators. We discuss if and how the desired proton bunches could be obtained in the CERN accelerator complex, considering various compression schemes, such as a fast non-adiabatic lattice change prior to extraction from a storage ring or the use of transversely deflecting cavities.
LBNL, Berkeley, California
TU Darmstadt, Darmstadt
GSI, Darmstadt
LLNL, Livermore, California
Ion acceleration from high-intensity, short-pulse laser irradiated thin foils has attracted much attention during the past decade. The emitted ion and, in particular, proton pulses contain large particle numbers (exceeding a trillion particles) with energies in the multi-MeV range and are tightly confined in time (< ps) and space (source radius a few micrometers). The generation of these high-current beams is a promising new area of research and has motivated pursuit of applications such as tabletop proton sources or pre-accelerators. Requirements for an injector are controllability, reproducibility and a narrow (quasi-monoenergetic) energy. However, the source provides a divergent beam with an exponential energy spectrum that exhibits a sharp cutoff at its maximum energy. The laser and plasma physics group of the TU Darmstadt, in collaboration with GSI and LBNL, is studying possibilities for transport and RF capture in conventional accelerator structures. First results on controlling laser-accelerated proton beams are presented, supported by WARP simulations.
MPI-P, München
BINP SB RAS, Novosibirsk
HHUD, Dusseldorf
The idea of proton bunch driven plasma wakefield acceleration was recently proposed. The motivation is to use an existing high energy proton beam to drive a large amplitude accelerating electric field, and then accelerate the electrons to the energy frontier. Simulations of the plasma wakefield production and acceleration process from a PIC code are given in this paper. In order to get high accelerating field, the required proton bunch length is extremely small. The preliminary design parameters for bunch compression are also presented.
UCLA, Los Angeles, California
Funding: This work is supported by the DOE Contract No. DE-FG03-92ER40727.
Over the last several years, the Target Normal Sheath Acceleration (TNSA) mechanism in solid density plasmas produced by a laser pulse has achieved proton energies up to 10’s of MeV and quasi-monoenergetic beams at lower energies. Although solid-target experiments have demonstrated high-charge and low-emittance proton beams, little work has been done with gaseous targets which in principle can be operated at a very high repetition frequency. At the Neptune Laboratory, there is an ongoing experiment on CO2 laser driven proton acceleration using a rectangular (0.5x2mm) H2 gas jet as a target. The main goal is to study the coupling of the laser pulse into a plasma with a well defined density in the range of 0.5 to 2 times critical density and characterize the corresponding spectra of accelerated protons. Towards this end, the Neptune TW CO2 laser system is being upgraded to produce shorter 1-3ps pulses. These high-power pulses will allow us to investigate acceleration of protons via the TNSA and Direct Ponderomotive Pressure mechanisms as well as their combination. The current status of the proton source experiment will be presented.
CERN, Geneva
EPFL, Lausanne
The CERN PS crosses transition energy at about 6 GeV by using a second order gamma jump performed with special quadrupoles. However, for high-intensity beams, and in particular the single bunch beam for the neutron Time-of-Flight facility, a controlled longitudinal emittance blow-up is still needed to prevent a fast single-bunch vertical instability from developing near transition. A series of studies have been done in the PS in 2008 to measure the beam behaviour near transition energy for different settings of the gamma transition jump. The purpose of this paper is to compare those measurements with simulations results from the HEADTAIL code, which should allow to understand better the different mechanisms involved and maybe improve the transition crossing.
Fermilab, Batavia
Funding: work supported by the US Department of Energy
Stability issues of the mu2e proton beam are discussed. These include space-charge distortion of bunch shape, microwave instabilities, head-tail instabilities, as well as electron cloud effects.
Fermilab, Batavia
We examine the stability of intense flat bunches in barrier buckets. We consider a class of stationary distributions and derive analytical expressions for the threshold intensity at which Landau damping is lost against rigid dipole oscillations in the presence of impedances and space charge forces. Particle simulations are used to follow the dynamics in a barrier bucket and compare with the analytic expressions. These studies are related to experimental observations in the Recycler ring at Fermilab.
KEK, Ibaraki
SLAC, Menlo Park, California
Funding: The Japan/US Cooperation Program
Beam instability caused by the electron cloud is expected to be a limiting factor in the performance of future advanced positron and proton storage rings. In a wiggler section of the positron ring of the KEK B-factory (KEKB), we have installed a vacuum chamber with an insertion that can be replaced and including different techniques to study the mitigation of the electron-cloud effect in a high magnetic field region. We have installed an insertion with strip-line clearing electrode, an insertion with triangular grooves and an insertion with a smooth surface, and compared them each other under the same conditions. The electrode insertion is composed of a thin tungsten layer formed on a thin alumina ceramic layer. The groove insertion is composed of TiN-coated triangular grooves running longitudinally. In this paper, we report about the tests in the KEKB and about the large reduction in the measured electron cloud density when the clearing electrode and groove sections are installed with respect to the smooth insertion. These experiments are the first ones demonstrating the principle of the clearing electrode and groove insertions in a magnetic field.
INFN/LNF, Frascati (Roma)
U. Sannio, Benevento
INFN-Salerno, Baronissi, Salerno
The electron cloud driven effects can limit the ability of recently build or planned accelerators to reach their design parameters. The secondary emission yield reduction (called "scrubbing") due to the fact that the electrons of the cloud hit the vacuum chamber wall, modifying its surface properties, may minimize any disturbing effects of the cloud to the beam. The dependence of "scrubbing" efficiency on beam and chamber parameters can be deduced from e-cloud simulation codes modeling the involved physics in full detail. In this communication we present a generalization of the map formalism, introduced in*,**, for the analysis of electron flux at the chamber wall with particular reference to the exploration of LHC conditioning scenarios. Simulations based on this formalism are orders of magnitude faster compared to those based on standard particle tracking codes.
*U.Iriso and S.Peggs, ”Maps for Electron Clouds”, Phys. Rev. ST-AB 8, 024403, 2005.
**T.Demma et al., ”Maps for Electron Clouds: Application To LHC”, Phys. Rev. ST-AB 10, 114401 (2007).
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
J-PARC, KEK & JAEA, Ibaraki-ken
The RCS of J-PARC accelerator complex has been commissioned since September 2007. By a study of one year, we were able to demonstrate more than 200kW operation. In such high intensity operation, the electron cloud effect may have an important roll for the accelerator limitation. we estimated the electron emission from the collimator surface of RCS by a simulation.
BNL, Upton, Long Island, New York
Funding: Work supported by Brookhaven Science Associates, LLC under Contract No. DE-AC02-98CH10886 with the U.S. Department of Energy.
An online modeling system is being developed for the RHIC injector complex, which consists of the Booster, the AGS and the transfer lines connecting the Booster to the AGS and the AGS to RHIC. Historically the injectors have been operated using static values from design specifications or offline model runs, but tighter beam optics constraints required by polarized proton running (e.g. accelerating with near-integer tunes) have necessitated a more dynamic system. An online model server for the AGS has been implemented using MAD-X as the model engine, with plans to extend the system to the Booster and the injector transfer lines and to add the option of calculating optics using the Polymorphic Tracking Code (PTC) as the model engine.
GSI, Darmstadt
IPCP, Chernogolovka, Moscow region
TU Darmstadt, Darmstadt
Universidad de Castilla-La Mancha, Ciudad Real
CERN, Geneva
When the LHC will work at full capacity, two counter rotating beams of 7 TeV/c protons will be generated. Each beam will consist of 2808 bunches while each bunch will comprise of 1.15x1011 protons. Bunch length will be 0.5 ns whereas two neighboring bunches will be separated by 25 ns . Intensity in the transverse direction will be Gaussian with σ = 0.2 mm. Each beam will carry 362 MJ energy, sufficient to melt 500 kg of Cu. Safety is an extremely important issue in case of such powerful beams. We report two–dimensional numerical simulations of hydrodynamic and thermodynamic response of a solid copper cylinder that is facially irradiated by one of the LHC beams in axial direction. The energy loss of protons in copper is calculated employing the FLUKA code and this data is used as input to a hydrodynamic code, BIG2. Our simulations show that the beam will penetrate up to 35 m into the solid copper target. Since the target is strongly heated by the beam, a sample of High Energy Density (HED) matter is generated. An additional application of the LHC, therefore will be, to study HED matte. This is an improvement of our previous work [Tahir et al., PRL 94 (2005) 135004].
CERN, Geneva
Construction work for the new CERN linear accelerator, Linac4, started in October 2008. Linac4 will replace the existing Linac2 and provide an H- beam at 160 MeV (as opposed to the present 50 MeV proton beam) for injection into the CERN PS Booster (PSB). The charge-exchange H- injection combined with the higher beam energy will allow for an increase in beam brightness required for reaching the ultimate LHC luminosity. Commissioning of Linac4 and of the transfer line to the PSB is planned for the last quarter of 2012. Appropriate beam instrumentation is foreseen to provide transverse and longitudinal beam characterization at the exit of Linac4 and in two dedicated measurement lines located before injection into the PSB. A detailed description of the diagnostics set, especially of spectrometer and emittance meter, and the upgrade of the measurement lines for Linac4 commissioning and operation is presented.
Fermilab, Batavia
NSCL, East Lansing, Michigan
ANL, Argonne
A superconducting cavity has been designed for acceleration of particles traveling at 81% the speed of light (beta = 0.81). The application of interest is an 8 GeV proton linac proposed for a Fermilab upgrade; at present, the cavity is to be used from 420 MeV to 1.3 GeV. The cavity is similar to the 805 MHz high-beta cavity developed for the SNS Linac, but the resonant frequency (1.3 GHz) and beam tube diameter (78 mm) are the same as for the beta = 1 cavities developed for the TESLA Test Facility. Four single-cell prototype cavities have been fabricated and tested. Two multi-cell prototypes have also been fabricated, but they have not yet been tested. The original concept was for an 8-cell cavity, but the final design and prototyping was done for 7 cells. An 11-cell cavity was proposed recently to allow the cryomodules for the beta = 0.81 cavity and downstream 9-cell beta = 1 cavities to be identical. The choice of number of cells per cavity affects the linac design in several ways. The impact of the number of cells in the 8 GeV linac design will be explored in this paper. Beam dynamics simulations from the ANL code TRACK will be presented.
IAP, Frankfurt am Main
GSI, Darmstadt
For the research program with cooled antiprotons at FAIR a dedicated 70MeV, 70mA proton injector is needed. The main acceleration of this room temperature injector will be provided by six coupled CH-cavities operated at 325MHz. Each cavity will be powered by a 3 MW klystron (6 in total). For the second acceleration unit from 11.7 to 24.3 MeV measurements on a 1:2 scaled model are performed. This tank is now ready for construction and will be used for RF power tests at GSI. The RF power test installations are underway. This paper presents the CH-DTL design and especially the status of the first power cavity.
Imperial College of Science and Technology, Department of Physics, London
The PAMELA project aims to design an ns-FFAG accelerator for cancer therapy using protons and carbon ions. For the injection system for carbon ions, an RFQ is one option for the first stage of acceleration. An integrated RFQ design process has been developed using various software packages to take the design parameters for the RFQ, convert this automatically to a CAD model using Autodesk Inventor, and calculate the electric field map for the CAD model using CST EM STUDIO. Particles can then be tracked through this field map using Pulsar Physics’ General Particle Tracer (GPT). Our software uses Visual Basic for Applications and MATLAB to automate this process and allow for optimisation of the RFQ design parameters based on particle dynamical considerations. Initial particle tracking simulations based on modifying the field map from the Front-End Test Stand (FETS) RFQ design have determined the best operating frequency for the PAMELA RFQ to be close to 200 MHz and the length approximately 2.3 m. The status of the injector design with an emphasis on the RFQ will be presented, together with the results of the particle tracking.
IUCF, Bloomington, Indiana
LANL, Los Alamos, New Mexico
Funding: LENS is supported by the National Science Foundation grants DMR-0220560 and DMR-0320627, the 21st Century Science and Technology fund of Indiana, Indiana University, and the Department of Defense.
The Indiana University Cyclotron Facility is operating a Low Energy Neutron Source which provides cold neutrons for material research and neutron physics as well as neutrons in the MeV energy range for neutron radiation effects studies. Neutrons are being produced by a 13 MeV proton beam incident on a Beryllium target. The LENS Proton Delivery System (PDS) is routinely operating at 13 MeV and 25 mA at 1.8% duty factor. The RF system, consisting of three Litton 5773 klystron RF tubes at 425 MHz and 1 MW each, power the AccSys Technology PL-13 Linac. The proton beam delivers 6 kilowatts of power to the Beryllium target. Details of the beam spreading system, target cooling system, and accelerator operations will be discussed.
KAERI, Daejon
Funding: This work is supported by MEST of the Korean Government
A 100 MeV DTL as a main accelerating section of the PEFP proton linac is under development. The PEFP proton linac consists of a 50 keV proton injector based on a duoplasmatron ion source, 3 MeV four-vane RFQ, 20 MeV DTL and 100 MeV DTL. The 100 MeV DTL is composed of 7 tanks and each tank is an assembly of 3 sections. The tank is made of seamless carbon steel and inside surface is electroplated with copper. Each drift tube contains an electroquadrupole magnet which is made of hollow conductor and iron yoke with epoxy molding. Following the fabrication of tanks and drift tubes, a precise alignment of drift tubes and field flatness tuning procedure are performed. Currently four DTL tanks out of seven are completed and the rest are under fabrication. The status of development and test results of the fabricated parts are reported in this paper.
LANL, Los Alamos, New Mexico
Muon accelerators are proposed world wide for future neutrino factory, muon colliders and other applications. One of the problem on accelerating muons is their large emittance as well as huge energy spreads. We carried out some simulation works on large acceptance muon linear accelerator that operates at mixed buncher / acceleration mode. The designed linac has following features: iris structure of 12 cm diameter, inject ~100 MeV muon beam and accelerates to several 100 MeV, 700 MHz and 25 MV/m peak field. Further acceleration of the muon beam can be easily done by extending the muon linear accelerator. According to the simulation, our linac can accelerates DC muon beam of 20 - 100 MeV range with 20 % phase acceptance.
Istituto Nazionale di Fisica Nucleare, Milano
Universita' degli Studi di Milano & INFN, Segrate
Naples University Federico II and INFN, Napoli
CERN, Geneva
Bari University, Science Faculty, Bari
e2v, Chelmsford, Essex
INFN-Bari, Bari
ACLIP is a proton 3 GHz SCL linac designed as a booster for a 30 MeV commercial cyclotron . The final energy is 60 MeV well suitable for the therapy of ocular tumours or for further acceleration (up to 230 MeV) by a second linac in order to treat deep seated tumours. ACLIP has a 5 modules structure coupled together. The first one (able to accelerate proton from 30 to 35 MeV) has been completely assembled. High power tests are in progress at e2v in Chelmsford, UK, where the possibility of using magnetrons as the source of RF power is under investigation. Acceleration tests are foreseen for Spring 2009. In this paper we will review the main features of the linac and discuss the results of RF measurements, high power RF tests and possibly acceleration tests.
Naples University Federico II and INFN, Napoli
Istituto Nazionale di Fisica Nucleare, Milano
Naples University Federico II, Napoli
The use of BBAC (Back-to-Back Accelerating Cavity) tiles in proton Side Coupled Linacs can be extended down to energies of the order of 20 MeV, keeping more than suitable shunt impedances and energy gradients. However, the considerable energy absorption from the cavity noses may induce a remarkable increase in their temperature. This may cause both a strong duty-cycle-dependent detuning of the modules, and dangerous thermo-mechanical stress due to the non-uniform temperature distribution. An innovative shape of the BBAC tile is proposed, which allows to limit the temperature rise within a safe range, without introducing detrimental effects neither on the shunt impedance nor on the working frequency. A protocol for the design of such a cavity will be presented.
Soreq NRC, Yavne
ACCEL, Bergisch Gladbach
The Soreq Applied Research Accelerator Facility, SARAF, is currently under construction at Soreq NRC. SARAF is based on a continuous wave (CW), proton/deuteron RF superconducting linear accelerator with variable energy (5–40 MeV) and current (0.04-2 mA). SARAF is designed to enable hands-on maintenance, which implies beam loss below 10-5 for the entire accelerator. Phase I of SARAF consists of a 20 keV/u ECR ion source, a low energy beam transport section, a 4-rod RFQ, a medium energy (1.5 MeV/u) transport section, a superconducting module housing 6 half-wave resonators and 3 superconducting solenoids, a diagnostic plate and a beam dump. Phase II will include 5 additional superconducting modules. The ECR source is in routine operation since 2006, the RFQ is in routine operation with protons since 2008 and has been further operated with molecular hydrogen and deuterons. The superconducting module is being operated and characterized with protons. Phase I commissioning results, their comparison to beam dynamics simulations and Phase II plans will be presented.
FZJ, Jülich
University of Erlangen-Nürnberg, Physikalisches Institut II, Erlangen
INFN-Ferrara, Ferrara
The PAX Collaboration is planning experiments using polarized Antiprotons. The only experimentally proven method so far which could lead to the production of polarized antiprotons is the spin-filtering. In particular, spin-filtering has been used to generate polarized protons in an experiment at the Heidelberg TSR*. In order to optimize spin-filtering for the production of polarized antiprotons dedicated experiments are planned at COSY with protons and AD (CERN) with antiprotons. The experimentation at COSY has already started in 2007. A decisive experiment has been performed to settle a long controversy about the role of electrons in the polarization buildup by spin-filtering. Instead of studying the polarization buildup in an initially unpolarized beam, the inverse situation was investigated by observation of depolarization of an initially polarized beam. For the first time the electrons of the electron cooler have been used as a target to study their depolarizing effects on the stored beam. At the same time a series of machine experiments have been performed to study the beam lifetime at different energies.
*F. Rathmann et al., Phys. Rev. Lett. 71, 1993, p.1379
University of Fukui, Faculty of Engineering, Fukui
KURRI, Osaka
FFAG DDS Research Organization, Tokyo
The accelerator–based neutron source using ERIT (Energy/emittance Recovery Internal Target) scheme has been constructed at KURRI (Kyoto University Research Reactor Institute). And the first beam test was successfully completed in March 2008. In this poster, recent status of beam studies will be presented.