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.
ANL, Argonne
Funding: This work was supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.
Construction of the DOE Californium Rare Ion Breeder Upgrade (CARIBU) for the ATLAS facility is expected to be completed by the end of 2008 and commissioning should be well along by the time of the conference. The facility will use fission fragments from a 1 Ci 252Cf source, thermalized and collected into a low-energy particle beam by a helium gas catcher, mass analyzed by an isobar separator, and charge breed to higher charge states for acceleration in ATLAS. In addition, unaccelerated beams will be available for trap and laser probe studies. Expected yields of accelerated beams are up to ~5x105 (107 to traps) far-from-stability ions per second on target. The facility design and first results of beam acceleration using a weaker 80 mCi source will be presented in this paper and plans for installation of the 1 Ci source will be discussed.
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.
ORNL, Oak Ridge, Tennessee
Solid-state based high-power modulators utilize new technology, yet must meet the operational needs of a high reliability facility. This modulator technology is in use at SNS, and is under consideration and development for future machines, such as the ILC and PEFP. Through operational experience and a sustained development effort, a number of improvements have been deployed in the SNS modulator system to meet the high availability demands of operating facilities. The operating experience and development effort of the world-wide community will also be reviewed.
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.
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.
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.
LPSC, Grenoble
SCK-CEN, Mol
IPHC, Strasbourg Cedex 2
LPC, Caen
CEA Cadarache, Saint Paul Lez Durance
IPN, Orsay
GUINEVERE, Generator-of-Uninterrupted-Intense-NEutrons-at-the-lead-VEnus-REactor, is devoted to ADS feasibility studies and to investigate on-line reactivity monitoring, sub-criticality determination and operational procedures. It will couple a versatile neutron source to the VENUS-F lead core at the SCK·CEN site in Mol (Belgium). It is based on an electrostatic accelerator generating 14 MeV neutrons by bombarding a deuteron beam on a tritium target located in the reactor core. A new accelerator has been developed. It will produce alternatively 1 μs 250 keV deuteron pulses with adjustable repetition rate (40 mA peak), as well as continuous beam (1 mA) with programmable interruptions. Beam will be inserted vertically into the reactor core. The accelerator is designed to enable the vertical section of the beam line to be easily lifted out the reactor bunker for maintenance operations, target changes and core loading procedures. This paper will describe the design of the accelerator and its commissioning in Grenoble (France), before its transfer to the Belgian site. This work is performed within the 6th Framework Program EC project EUROTRANS.
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.
LBNL, Berkeley, California
Funding: This work is supported by NA22 of NNSA under the Department of Energy contract No. DE-AC02-05CH11231.
Active neutron interrogation has been demonstrated to be an effective method of detecting shielded fissile material. A fast fall-time/fast pulsing neutron generator is needed primarily for differential die-away technique (DDA) interrogation systems. A compact neutron generator, currently being developed in Lawrence Berkeley National Laboratory, employs an array of 0.25-mm-dia apertures (instead of one 5-mm-dia aperture) such that gating the beamlets can be done with low voltage and a small gap to achieve sub-microsecond ion beam fall time and low background neutrons. The system will aim at both high and low beam current applications. We have designed and fabricated an array of 16 apertures (4x4) for a beam extraction experiment. Our preliminary results showed that, using a gating voltage of less than 800 V and a gap distance of 1 mm, the fall time of extracted ion beam pulses is less than 1 ms at various beam energies ranging between 200 eV to 600 eV. More experimental results with an array of 20×20 apertures will be presented.
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.
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
The J-PARC 3-GeV rapid cycling synchrotron (RCS) has been beam commissioned since October 2007 and it has been able to provide downstream facilities, the 50-GeV synchrotron (MR) and the Materials and Life Science Facility (MLF) with stable beam required from them. After beam deliver operation to the MR and MLF, while the priority ha s been given to their beam tuning, the RCS also continues further beam studies toward higher beam intensity. On September 18th, 2008, the RCS achieved the beam power of 210kW to beam dump with 25Hz. This presentation will concentrate itself on the outcome of the J-PARC RCS commissioning program, including the discussion on the issues of the high-power operation.
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.
ORNL, Oak Ridge, Tennessee
Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy
The Spallation Neutron Source (SNS) is a second generation pulsed-neutron source and designed to provide a 1-GeV, 1.44-MW proton beam to a mercury target for neutron production. Since the initial commissioning of accelerator complex in 2006, the SNS has begun neutron production operation and beam power ramp-up has been in progress toward the design goal. Since the design beam power is almost an order of magnitude higher compared to existing neutron facilities, all subsystems of the SNS were designed and developed for substantial improvements compared to existing accelerators and some subsystems are first of a kind. Many performance and reliability aspects were unknown and unpredictable, for which it takes time to understand the systems as a whole and/or needs additional performance improvements. A power ramp-up plan has been revised based on the operation experiences and understandings of limits and limiting conditions through extensive studies with an emphasis on machine availability. In this paper the operational experiences of SNS Superconducting Linac (SCL), the power ramp-up status and plans will be presented including related subsystem issues.
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.
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.
JAEA, Ibaraki-ken
RIST, Ibaraki
NSCL, East Lansing, Michigan
Funding: The funding information for R.M. Ronningen is U.S. Department of Energy Grant Number DE-FG02-08ER41548.
The Particle and Heavy Ion Transport Code (PHITS)* has been typically used to predict radiation levels around high-energy (above 100 MeV/u) heavy-ion accelerator facilities. However, predictions of radiation levels around low-energy (around 10 MeV/u) heavy-ion facilities are also desirable, but the reliability of PHITS at low energies has not been investigated. In this work, neutron energy spectra from 10 MeV/u 12C and 16O ions incident on C and Cu targets have been calculated using the quantum molecular dynamics (QMD) model coupled to the generalized evaporation model (GEM) in PHITS. In particular, the influence of the “switching time”, defined as the time when the QMD calculation is stopped and the calculation switches to the GEM model, was studied. The calculated neutron energy spectra obtained using a value of 100 fm/c for the switching time agree well with the experimental data. We have also used PHITS to simulate an experimental study by Ohnesorge et al.**, by calculating neutron dose equivalent rates, for 3-16 MeV/u 12C, 16O and 20Ne beams incident on Fe, Ni and Cu targets. The calculated neutron dose equivalent rates agree well with the data.
*H. Iwase, K. Niita and T. Nakamura, J. Nucl. Sci. Technol. 39, 1142 (2002).
**W.F. Ohnesorge, H.M.Butler, C.B.Fulmer and S.W.Mosko, Health Physics 39, 633 (1980).
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.
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.
SLAC, Menlo Park, California
ORNL, Oak Ridge, Tennessee
Funding: Work supported by the Department of Energy under contract No. DE-AC02-76SF00515.
The 1-MW High Voltage Converter Modulators* have operated in excess of 250,000 hours at the Spallation Neutron Source. Increased demands on the accelerator performance require increased modulator reliability. An effort is underway at SLAC National Accelerator Laboratory to redesign the modulator H-bridge switch plate with the goals of increasing reliability and performance**. The major difference between the SLAC design and the existing design is the use of press-pack IGBTs. Compared to other packaging options, these IGBTs have been shown to have increased performance in pulsed-power applications, have increased cooling capability, and do not fragment and disassemble during a fault event. An overview of the SLAC switch plate redesign is presented. Design steps including electrical modeling of the modulator and H-bridge, development of an integrated IGBT clamping mechanism, and heat sink performance validation are discussed. Experimental results will be presented comparing electrical performance of the SLAC switch plate to the existing switchplate under normal and fault conditions.
*W. A. Reass, et al., “Design, Status, and First Operations of the Spallation Neutron Source Polyphase
”, PAC, 2003
**M.A. Kemp, et al., “Next Generation IGBT Switch Plate
,” LINAC, 2008.
ORNL, Oak Ridge, Tennessee
Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy
Latest technologies promise new control systems user interface features and greater interoperability of applications. New developments using Java and Eclipse aim to unify diverse control systems and make communication between applications seamless. Web based user interfaces can improve portability and remote access. Modern programming tool improve efficiency, support testing and facilitate shared code. This talk will discuss new developments aimed at improving control system interfaces and their development environment.
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 RAD, Oak Ridge, Tennessee
ORNL, Oak Ridge, Tennessee
Funding: SNS is managed by UT-Battelle, LLC, under contract DE-AC05-00OR22725 for the U.S. Department of Energy.
Over the past year the performance of the LBNL H- source has been improved to routinely produce 36 mA when averaged over 0.7 ms long pulses at 60 Hz, measured at the RFQ output of the Spallation Neutron Source accelerator. This is up from 25-30 mA during early 2008, and up from {10}-20 mA during 2007. Some of the recent gain was achieved with refined conditioning and cesiation procedures, which now yield peak performance within 8 hours of starting a source change. The ~10 mg released Cs is sufficient for 3 weeks of operation without significant degradation. Another recent gain comes from the elevated Cs collar temperature, which was gradually implemented to probe its impact on the performance lifetime. In addition, load resistors improve the voltage stability of the electron dump and the lenses, which now can be more finely tuned. The achieved gain allowed for lowering the RF power to ~50 kW for improved reliability. A beam current of 38 mA is required at SNS for producing neutrons with a proton beam power of 1.4 MW. In one case, after 12 days of 4% duty factor operation, 56 mA were demonstrated with 60 kW of RF power. This is close to the 59 mA required for 3 MW operations.
JLAB, Newport News, Virginia
Helium refrigerators are of keen interest to present and future particle physics programs utilizing superconducting magnet or radio frequency (RF) technology. They typically utilize helium refrigeration at and below 4.5-Kelvin (K) temperatures and are very energy intensive. After an overview of the quality of energy, basic processes used for cryogenics, the Carnot step (as defined by the author) and cycle design theory, the concept of overall process optimization is presented. In particular the question of ‘what is an optimum system’ will be discussed. In this regard, the Ganni cycle and floating pressure control philosophy will be examined with respect to a more traditional approach as a solution to an optimum system for new designs and existing systems.
ORNL, Oak Ridge, Tennessee
The Spallation Neutron Source (SNS) has recently installed a prototype low level radio frequency (LLRF) control system for initial testing. This system is designed to replace the original fixed frequency, two harmonic Accumulator Ring LLRF system used to maintain a gap in the proton beam for extraction to the target. This prototype system is based on the hardware for the Linac LLRF system that has been modified to operate at the low frequencies required for the ring. The goal of the final system is to leverage the mature hardware and software of the Linac systems with the added flexibility needed to support the heavy beam loading requirements of the Accumulator Ring.
BNL, Upton, Long Island, New York
Funding: Work performed under Contract Number DE-AC02-98CH10886 under the auspices of the US Department of Energy.
Using the Vernier Scan (or Van der Meer Scan technique), where one beam is swept stepwise across the other while measuring the collision rate as a function of beam displacement, the transverse beam profiles, the luminosity and the effective cross section of the collision monitoring processes can be measured. Data and results from the 2005, 2006 and 2008 polarizded proton runs using different collision detectors are presented and compared.
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.
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.
STFC/DL/ASTeC, Daresbury, Warrington, Cheshire
CERN, Geneva
Linac4 is a 160 MeV H- linac which will replace the existing Linac2, a 50 MeV proton linac, at CERN as a first step of the upgraded LHC proton injector chain. No collimation system is foreseen in the baseline design but it will become mandatory for opreation at highest duty cycle in order to reduce activation of the machine. Such a system will also help to reduce activation at low duty cycle. A review of different collimation options, initial studies on collimator designs capable of intercepting beam power of 10, 25 and 50 Watts at energies between 50 and 160 MeV, the activation of such designs and the downstream elements are shown in this paper.
ORNL, Oak Ridge, Tennessee
There are many planned or nascent particle-accelerator-based projects world-wide. Often these are large and complex projects that can benefit from strong project management. Following the premise that it is better to learn from the community’s successes rather than its mistakes, this talk will draw on successful experiences from the Oak Ridge SNS project in elaborating strategies and techniques for successful project management.
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.
ANL, Argonne
SLAC, Menlo Park, California
Funding: Work supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences, under contract number DE-AC02-06CH11357.
Simulations of the beam loss monitor (BLM) system built at the Advanced Photon Source (APS) for the Linear Coherent Light Source (LCLS) have been carried out using the Monte Carlo particle tracking code MARS. Cerenkov radiation generated by fast electrons in the quartz radiator of the BLM produces the signal used to estimate beam loss and dose in the LCLS undulator magnets. The calibration of the BLM signal with radiation components that cause undulator damage is the goal of the simulation effort. Beam loss has been simulated for several scenarios including undulator magnets in the normal operating position, “rolled-out” 80 mm from the beamline, and absent altogether. Beam loss is generated when an electron bunch strikes one of two targets: Al foil or carbon wire. In the former case, the foil is placed at OTR33, 85.8 m upstream of the FEL; in the latter, the first undulator beam finder wire (BFW01) position is used just upstream of the first magnet. The LCLS MARS model includes quadrupole focusing between OTR33 and the end of the FEL. The FODO lattice leads to complex loss patterns in the undulators consistent with betatron envelope maximums in both transverse planes.
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.
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.
LANL, Los Alamos, New Mexico
Funding: US DOE
The Compact Reconfigurable Input/Output (cRIO) hardware manufactured by National Instruments (NI) is evaluated as a wire scanner motion controller. This particular configuration utilizes a NI cRIO-9074 system combined with various C-series modules for wire scanner motion control I/O. Programs for this system have been written in LabVIEW and a majority of the motion-control functionality has been programmed into the cRIO's FPGA in order to provide the fastest motion control processing possible with cRIO. Additional topics of interest include, cRIO-based resolver-to-digital conversion and closed-loop, stepper-based motion control
ANL, Argonne
Funding: This work is supported by the U.S. Department of Energy, Office of Nuclear Physics, under Contract No. DE-AC02-06CH11357.
A Cf-252 fission source yields neutron-rich fission fragments. The CAlifornium Rare Ion Breeder Upgrade (CARIBU) project is an upgrade to the Argonne Tandem Linear Accelerator System (ATLAS) that provides a 37 GBq (1 Ci) source of these radioactive ions for acceleration. Fission fragments stop in a gas catcher, are extracted into an ECR ion source to increase the charge state, and then accelerated in ATLAS. The radiation fields produced by an unshielded 1 Ci 252Cf source are 46 rem/hr (neutron) and 4 R/hr (gamma) at 30 cm. A shielding system has been constructed that reduces the radiation fields to ≤ 1 mrem/hr at 30 cm from all accessible surfaces. The MCNPX code was used to model the transport of the spontaneous fission neutrons and gamma radiation, and the gamma radiation induced in the shielding materials by the neutrons. The primary neutron shielding material chosen was 5% borated polyethylene, enclosed in steel. Calculations are made for emissions of radioactive effluents, primarily noble gases, using the EPA CAP-88 computer program. The maximum credible incident scenario releases a small quantity of Cf-252. Calculated dose results and mitigation methods are presented.
ANL, Argonne
Northern Illinois University, DeKalb, Illinois
An exotic beam facility for the production of rare isotopes such as the Facility for Rare Isotope Beams (FRIB) at Michigan State University will require a high resolution fragment separator to separate isotopes of varying mass and charge. The goal of the fragment separator is to produce a high-purity beam of one rare isotope. Sources of contamination in a beam such as this are isotopes with a similar magnetic rigidity to the separated isotope and those which are produced by fragmentation in the energy degrader. This can be particularly detrimental when a contaminating isotope has a large cross section. Here we investigate beam purity as a function of the separated isotope and the type of fragment separator setup used, i.e. one stage, two stage, or one stage with gas cell branch.
ORNL, Oak Ridge, Tennessee
BINP SB RAS, Novosibirsk
Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.
Conversion of BLM readings into number of lost particles is a challenging task. Any insertion device is a good mean to obtain a localized loss and obtain such conversion factor with direct measurement. Such a measurement serves as a good benchmark for Monte-Carlo simulation of radiation transport. We used wire scanners and scraper induced losses to perform analysis of BLM response to local loss. The paper also provides a technique to measure 0.1% of full beam charge being intercepted by scraper during 650kW production run extracting the useful signal from high noise (20 times higher than signal) environment
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.
Cosylab, Ljubljana
ORNL RAD, Oak Ridge, Tennessee
ORNL, Oak Ridge, Tennessee
Funding: This manuscript has been authored by UT-Battelle, LLC, under contract DE-AC05-00OR22725 with the U.S. Department of Energy.
Implementation of a timing system master device is a complicated task, since a lot of details have to be taken into account even once the architecture decisions have been laid down. At SNS/ORNL timing master controller is being upgraded in collaboration with Cosylab and this paper focuses on some details of its implementation. New timing system master device is based on agile FPGA circuitry and the main focus of this paper is its firmware implementation. Provided are implementation details for event distribution supporting multiple event sources and priorities. Discussed are mechanisms, ensuring deterministic behavior, different methods of encoding that have been employed, and host-independent distribution of time stamp frames. The concept of the super-cycle is explained and its implementation is laid down. Taken into account that implementation for such a complex device involves extensive testing, paper provides insight into verification it was applied. Advantages of the SystemC based test-benches over traditional VHDL-only verification are discussed.
ORNL, Oak Ridge, Tennessee
Powerful new tools for neutron-based research are coming on line throughout the world. After summarizing developments that have permitted spallation neutron sources to reach the megawatt threshold, the speaker will describe opportunities to improve performance, both by delivering higher power and by making more effective use of available power. In discussing the new science that is being or will be produced by this new generation of neutron sources, the speaker will highlight recent results from the Spallation Neutron Source and review progress on current projects in Europe and Asia.
LBNL, Berkeley, California
Funding: This work supported by DARPA and US DoE Office of High Energy Physics under contract DE-AC02-05CH11231.
Ultrashort terahertz pulses with energies in the μJ range can be generated with laser wakefield accelerators (LWFA), which produce ultrashort electron bunches with energies up to 1 GeV* and energy spreads of a few-percent. At the plasma-vacuum interface these ultrashort bunches emit coherent transition radiation (CTR) in a wide bandwidth (~ 1 - 10 THz) yielding terahertz pulses of high intensity**,***. In addition to providing a non-invasive bunch-length diagnostic**** and thus feedback for the LWFA, these high peak power THz pulses are suitable for high field (MV/cm) pump-probe experiments. Maximizing the radiated energy was done by controlling the THz mode quality and by optimizing both the energy and the charge of the electron bunches via pre-pulse control on the driver beam. Here we present the study of three different techniques for pre-pulse control and we demonstrate the production of μJ-class THz pulses using energy-based and single-shot electro-optic measurements.
*W.P. Leemans et al., Nature Physics 2, 696 (2006)
**W.P. Leemans et al., PRL 91, 074802 (2003)
***C.B. Schroeder et al., PRE 69, 016501 (2004)
**** J. van Tilborg et al., PRL 96, 014801 (2006)
ORNL, Oak Ridge, Tennessee
RAS/INR, Moscow
Funding: ORNL/SNS is managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.
SNS is a high intensity hadron beam facility; so the Beam Loss Monitor (BLM) system is a crucial part of Machine Protection System and an important tool for beam tuning. The paper presents the current status of installed detectors and experimental data obtained during SNS operations. We compare several different types of BLMs and show advantages and disadvantages of each type. The electronic parts obsolescence became a real issue since the original electronics was designed about 10 years ago. The first test of our next generation BLM system is expected to be done by summer 2009. The new system will contribute to significant noise reduction and will follow a modular concept of Smart Device to achieve a higher degree of reliability and maintainability.
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.
University of Fukui, Faculty of Engineering, Fukui
KURRI, Osaka
FFAG DDS Research Organization, Tokyo
The acceleratorbased 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.
ORNL, Oak Ridge, Tennessee
Funding: *Managed by UT-Battelle, LLC, for the U.S. Department of Energy under contract DE-AC05-00OR22725.
HRIBF produces high-quality beams of short-lived radioactive isotopes for nuclear science research, and is currently unique worldwide in the ability to provide neutron-rich fission fragment beams post-accelerated to energies above the Coulomb barrier. HRIBF is undergoing a multi-phase upgrade. Phase I (completed 2005) was construction of the High Power Target Laboratory to provide the on-going Isotope Separator On-Line development program with a venue for testing new targets, ion sources, and radioactive ion beam (RIB) production techniques with high-power ORIC beams. Presently under way is Phase II, the Injector for Radioactive Ion Species 2, a second RIB production station that will improve facility reliability and accommodate new ion sources, RIB production, and RIB purification techniques, including laser applications. The Phase III goal is to substantially improve facility performance by replacing or supplementing the Oak Ridge Isochronous Cyclotron production accelerator with either a high-power 25-50 MeV electron accelerator or a high-current multi-beam commercial cyclotron. Either upgrade is applicable to R&D on isotope production for medical or other applications.