DESY, Hamburg
International collabollations on high energy physics will be described, referring its long history and with emphasis on the recent activity based on ICFA.
BNL, Upton, Long Island, New York
FRIB, East Lansing, Michigan
We present a medium-energy (4 GeV) electron ion collider (MeRHIC) lattice design for the Relativistic Heavy Ion Collider (RHIC). MeRHIC represents a staged approach towards the higher energy eRHIC, with MeRHIC hardware being reused for eRHIC. The lattice design includes two Energy Recovery Linacs (ERLs), multiple isochronous arcs connected to the ERLs, an interaction region design, a low energy ERL with a polarized electron source, and connecting beam lines.
* V. Litvinenko, proceedings from this conference.
GUAS, Kanagawa
KEK, Ibaraki
Tsukuba University of Technology, Kasuga Campus, Tsukuba, Ibaraki
Japanese research to build accelerators for high energy physics started with Electron Synchrotron at Institute of Nuclear Study, Tokyo (INS). The development was slow in the beginning, in particular before the construction of KEK-PS. After the experience of TRISTAN, KEKB, one of the best colliders in the world, was eventually constructed. We will review the history of high energy accelerators in Japan from physics, technological and particularly social points of view referring to documents at KEK and other archives. This is the first of a series of papers and will outline the over-all view.
JINR, Dubna, Moscow Region
NICA (Nuclotron-based Ion Collider fAcility) is the new accelerator complex currently under construction at JINR. The facility is aimed to provide collider experiments with heavy ions up to uranium (gold at the beginning stage) with a centre of mass energy up to 11 GeV/u and an average luminosity up to 1027 cm-2 s-1. The collisions of polarized deuterons and protons are foreseen also. The accelerator complex includes two injector linacs, a superconducting booster synchrotron, a 6 GeV/u superconducting synchrotron (existing Nuclotron) and a collider consisting of two storage rings. Different modifications of superferric magnets based on a hollow composite NbTi cable operating at 4.5 K is proposed to be used for the NICA booster and collider rings. The twin-aperture collider dipole consists of two vertically assembled cold masses placed inside a common thermal shield and a common cryostat. The dipole good field aperture is fixed to 60 mm. The 2 T option, which design is very similar to the Nuclotron's one, was fixed as basis for the collider of 350 m long. R&D work on a curved 4 T Cosine(θ)-dipoles based on a hollow Nuclotron-type cable is proposed to be continued.
Fermilab, Batavia
Conceptual designs of superconducting magnets (dipoles and quadrupoles) for a muon collider with a 1.5 TeV c.o.m. energy and an average luminosity of 1034 cm-2s-1 are presented. All magnets are based on the Nb3Sn superconductor and designed to provide an adequate operation field/field gradient in the aperture with the critical current margin required for reliable machine operation. In contrary to proton machines, the dipole magnets should have open midplanes, and, for some of them, the required good field quality region needs to have a vertical aspect ratio of 2:1 that imposes additional challenges for the magnet design. Magnet cross-sections were optimized to achieve the best possible field quality in the magnet aperture occupied with beams. The magnets and corresponding protective measures are designed to handle about 0.5 kW/m of dynamic heat loads from the muon beam decays. Magnet parameters are reported and compared with the requirements.
Muons, Inc, Batavia
North Carolina State University, Raleigh, North Carolina
YBCO superconductors originally developed for high temperature operation carry significant critical current even in the presence of extremely high magnetic field when operated at low temperature. The final stage of phase space cooling for a muon collider uses a solenoid magnet with fields approaching 50 T. As part of an R&D effort we present measurements of mechanical and electromechanical properties of the YBCO conductor. We examine the critical current verses magnet field angle at 4.2 K in a magnetic field. Quench properties of the conductor such as minimum quench energy threshold and quench propagation velocity will be measured to establish safe operational conductions for the muon cooling magnets. In this paper we describe a conceptual picture for a high field solenoid to be used for muon phase space cooling that incorporates these low temperature properties of YBCO.
Tokyo Denkai Co., Ltd., Tokyo
KEK, Ibaraki
TKX Corporation, Osaka
KEK and Tokyo Denkai have developed new niobium ingot slicing technique. 150 pieces of the large grain niobium discs can be sliced in two days by using of this technique. Tokyo Denkai installed the slicing machine in December 2009. During the development of the slicing technique, we found that crystal growth mechanism in Electron Beam Melting. It gave us the suggestion to make a single crystal niobium ingot. This paper describes the production process of low cost and short production time niobium discs and single crystal niobium ingot development.
CERN, Geneva
The role of "Experimental Area Manager" supported by a well organized, charismatic and motivated team is absolutely essential for managing the huge effort needed for a multi-cultural, multi-disciplinary installation of cathedral-size underground caverns housing a billion dollar physics experiment. Between the years 2002 and 2008, we supervised and coordinated the ATLAS work site at LHC, from the end of the civil engineering to the first circulating beams, culminating with 240 workers on the site, 24 hours a day, 7 days a week, with activities taking place simultaneously on the surface, in the 60 m shafts and in the 100 m underground experimental cavern. We depict the activities preparation scheme (including tasks ranging from the installation of 280 ton cranes to super-delicate silicon detectors), the work-site organization method, the safety management that was a top priority throughout the whole project, and the open-communication strategy that required maintaining permanent public visits. The accumulation of experience enables us to summarize the critical success factors for a timely and successful completion of such a vast and complex project.
BNL, Upton, Long Island, New York
CERN, Geneva
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 detector in question can be measured. This report briefly recalls the vernier scan method and presents results from the first RHIC polarized proton run at 250 GeV/beam in 2009.
JINR, Dubna, Moscow Region
Fermilab, Batavia
FZJ, Jülich
Main element of the NICA facility is the collider equipped with stochastic and electron cooling systems to provide experiment with heavy ions like Au, Pb or U at energy from 1 to 4.5 GeV/u with average luminosity of the level of 1027 cm-2 s-1. The possible lattices providing the required parameters are discussed.
JINR, Dubna, Moscow Region
JINR/LHE, Moscow
The Nuclotron-based Ion Collider fAcility (NICA) is the new accelerator complex being constructed at JINR aimed to provide collider experiments with heavy ions up to uranium at the center of mass energy from 4 to 11 GeV/u. It includes 6 Mev/u linac, 600 MeV/u booster, upgraded SC synchrotron Nuclotron and collider consisting of two SC rings, which provide average luminosity of the level of 1027cm-2s-1.
GSI, Darmstadt
Nagaoka University of Technology, Nagaoka, Niigata
FZJ, Jülich
JINR, Dubna, Moscow Region
The stochastic cooling is employed to reduce the momentum spread of accelerated 2 GeV proton beam at COSY. In addition the barrier voltages are successfully used to compensate the mean energy loss of the beam due to the thick internal target such as pellet target. To analyze the experimental results at COSY, we have developed the particle tracking code which simulate the particle behavior under the influences of stochastic cooling force, Schottky diffusion, thermal diffusion and IBS effects. The synchrotron motion due to the RF fields are included with 4th order symplectic way. The simulation results are well in agreement with the observed cooling process for the case of barrier voltage as well as RF field of harmonic number=1. In the present paper, the systematic analysis of the experimental results with use of the developed tracking codes are described. In addition the process of short bunch formation at the heavy ion collider at NICA project is investigated with use of the stochastic cooling. In that case the strong IBS effects are main limiting factor of making and keeping the short bunch as well as the space charge effects. Details of the simulation study will be presented.
GSI, Darmstadt
Nagaoka University of Technology, Nagaoka, Niigata
FZJ, Jülich
JINR, Dubna, Moscow Region
Anti-proton beam accumulation at CERN and FNAL has been performed with use of stochastic stacking in the momentum space. Thus accumulated beam has a large momentum spread and resultantly large radial beam size with large dispersion ring. In the present proposed scenario, beams from the pre-cooling ring are injected into the longitudinal empty space prepared by the barrier voltages and subsequently the stochastic cooling is applied. After the well cooling, barrier voltages will prepare again the empty space for the next beam injection. We have simulated the stacking process up to 100 stacking with use of the bunched beam tracking code including the stochastic cooling force and the diffusion force such as Schottky diffusion term, thermal diffusion, IBS effects. The synchrotron motion by barrier voltages are included with 4th order symplectic method. Examples of the application to 3 GeV anti-proton beam for the HESR ring in FAIR project are presented as well as the accumulation of heavy ion beam 3.5 GeV/u Au, at the NICA collider at JINR project.
INFN/LNF, Frascati (Roma)
Università degli Studi di Firenze, Firenze
INOA, Firenze
VIGO System S.A., Ozarow Maz.
At the LNF of INFN an IR array detector with a ns response time has been built and assembled in order to collect the IR image of the e-/e+ sources at DAΦNE. Such detector is made by 32 bilinear pixels with a pixel size of 50x50 μm2 and a response time of 1 ns. The device with its electronic board has been assembled for the installation on the e+ ring of DAΦNE in the framework of an experiment funded by the INFN Vth Committee dedicated to beam diagnostics. A preliminary characterization of few pixels of the array and of the electronics has been carried out at the IR beamline SINBAD at DAΦNE. In particular the detection of the IR source of the e- beam has been observed using four pixels of the array acquiring signals simultaneously with a 4 channels scope at 1GHz and at 4 Gsamples/s. The acquisition of 4 pixels allowed monitoring in real time differences in the bunch signals in the vertical direction. Preliminary analysis of data is presented and discussed. In particular we will outline how the differences in the signals can be correlated to small displacements of the source after the bunch refilling and during a complete shift of DAΦNE and before the refilling of electrons.
KEK, Ibaraki
Crab cavities were installed in the KEKB rings in order to increase the luminosity. We measured the tilt of the bunches in the x-z plane using streak cameras. In a previous report*, the measured tilt in the HER was 2 times smaller than the expected crabbing angle, while the LER measurement was consistent with that expected. After the streak camera's vertical sweep speed was calibrated, the results were consistent with the expected crabbing angle in both rings.
* H. Ikeda et al., PAC07, 4018.
Fermilab, Batavia
UMiss, University, Mississippi
There are conflicting requirements on the value of the momentum compaction factor during energy ramp in a synchrotron: at low energies it should be positive and sufficiently large to make the slippage factor small so that it is possible to work closer to the RF voltage crest and ensure sufficient RF bucket area, whereas at higher energies it should be small or negative to avoid transition crossing. In the present report we propose a lattice with variable momentum compaction factor and consider the possibility of using it in a high repetition rate proton driver for muon collider and neutrino factory.
RadiaBeam, Marina del Rey
INFN/LNF, Frascati (Roma)
UCLA, Los Angeles, California
BNL, Upton, Long Island, New York
The quest for detailed information concerning ultra-fast beam configurations, phase spaces and high energy operation is a critical task in the world of linear colliders and X-ray FELs. Huge enhancements in diagnostic resolutions are represented by RF deflectors. In this scenario, Radiabeam Technologies has developed an X-band Travelling wave Deflector (XTD) in order to perform longitudinal characterization of the subpicosecond ultra-relativistic electron beams. The device is optimized to obtain a single digit femtosecond resolution using 100 MeV electron beam parameters at the Accelerator Test Facility (ATF) at Brookhaven National Laboratory; however, the design can be easily extended to be utilized for diagnostics of GeV-class beams. The XTD design fabrication and tuning results will be discussed, as well as installation and commissioning plans at ATF.
* J. England et al., "X-Band Dipole Mode Deflecting Cavity for the UCLA Neptune Beamline".
** D. Alesini, "RF deflector-based sub-ps beam diagnostics: application to FELs and advanced accelerators".
University of Notre Dame, Notre Dame
Royal Holloway, University of London, Surrey
JAI, Egham, Surrey
KEK, Ibaraki
SLAC, Menlo Park, California
The demonstration of the stability of the position of the focused beam is a primary goal of the ATF2 project. We have installed a laser interferometer system that will eventually correct the measurement of high-precision Beam Position Monitors used in the ATF2 Final Focus Steering Feedback for mechanical motion or vibrations. Here, we describe the installed system and present preliminary data on the short- and long-term mechanical stability of the BPM system.
Fermilab, Batavia
CERN, Geneva
IHEP Protvino, Protvino, Moscow Region
INFN-Ferrara, Ferrara
PNPI, Gatchina, Leningrad District
BNL, Upton, Long Island, New York
The T980 crystal collimation experiment is underway at the Tevatron to study various crystal types and parameters and evaluate if this technique would increase TeV beam-halo collimation efficiency at high-energy hadron colliders such as the Tevatron and the LHC. The setup has been substantially enhanced during the Summer 2009 shutdown by installing a new O-shaped crystal in the horizontal goniometer, adding a vertical goniometer with two alternating crystals (O-shaped and multi-strip) and additional beam diagnostics. First measurements with the new system are quite encouraging, with channeled and volume-reflected beams observed on the secondary collimators as predicted. Investigation of crystal collimation efficiencies with crystals in volume reflection and channeling modes are described in comparison with an amorphous primary collimator. Results on the system performance are presented for the end-of-store studies and for entire collider stores. Planning is underway for dedicated studies during a Tevatron post-collider physics running period.
CERN, Geneva
The CLIC main beam quadrupoles need to be stabilized to 1.5 nm integrated R.M.S. displacement at 1 Hz. The choice was made to apply active stabilization with piezoelectric actuators in a rigid support with flexural guides. The advantages of this choice are the robustness against external forces and the possibility to make fast incremental nanometre positioning of the magnet with the same actuators. The study and feasibility demonstration is made in several steps from a single degree of freedom system (s.d.o.f.) with a small mass, a s.d.o.f. with a large mass, leading to the demonstration including the smallest (type 1) and largest (type 4) CLIC main beam quadrupoles. The paper discusses the choices of the position and orientation of the actuators and the tailored rigidities of the flexural hinges in the multi degree of freedom system, and the corresponding MIMO control system. The compatibility with the magnet support and micrometer alignment system is essential. The status of the study and performed tests will be given.
Fermilab, Batavia
As the Fermilab Tevatron Collider program draws to a close, a strategy has emerged of an experimental program built around the high intensity frontier. The centerpiece of this program is a superconducting H- linac that 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 provide multi-MW beams at 60-120 GeV from the Main Injector, simultaneous with very high intensity beams at lower energies. Project X also supports development of a Muon Collider as a future facility at the energy frontier.
CERN, Geneva
Mission critical systems at the European Organisation for Nuclear Research (CERN) make extensive use of Programmable Logic Devices (PLDs) such as Field Programmable Gate Arrays (FPGAs) to implement their safety critical functions. The dependability of these safety critical functions is difficult to determine using traditional techniques. A robust approach is needed if PLD technology is to be accepted in mission critical systems. This paper discusses techniques which are being developed and employed by CERN to give confidence in the use of PLDs in mission critical systems, the Safe Machine Parameter system development is used as an example.
INFN/LNF, Frascati (Roma)
An innovatory interaction region has been recently conceived and realized on the Frascati DAΦNE lepton collider. The concept of tight focusing and small crossing angle adopted until now to achieve high luminosity in multibunch collisions has evolved towards enhanced beam focusing at the interaction point with large horizontal crossing angle, thanks to a new compensation mechanism for the beam-beam resonances. The novel configuration has been tested with a small detector without solenoidal field yielding a remarkable improvement in term of peak as well as integrated luminosity. The high luminosity interaction region has now been modified to host a large detector with a strong solenoidal field integral which significantly perturbs the beam optics introducing new design challenges in terms of interaction region optics design, beam transverse coupling control and beam stay clear requirements.
INFN/LNF, Frascati (Roma)
CERN, Geneva
BINP SB RAS, Novosibirsk
Recently the peak luminosity achieved on the DAΦNE collider has been improved by almost a factor 3 by implementing a novel collision scheme based on large Piwinski angle and Crab-Waist. This encouraging result opened new perspectives for physics research and a new run with the KLOE-2 detector has been scheduled to start by spring 2010. The KLOE-2 installation is a complex operation requiring a careful design effort and a several months long shutdown. The high luminosity interaction region has been deeply revised in order to take into account the effect on the beam caused by the solenoidal field of the experimental detector and to ensure background rejection. The shutdown has been also used to implement several other modifications aimed at improving beam dynamics: the wiggler poles have been displaced from the magnet axis in order to cancel high order terms in the field, the feedback systems have been equipped with stronger power supplies and more efficient kickers and electrodes have been inserted inside the wiggler and the dipole vacuum chambers, in the positron ring, to avoid the e-cloud formation. A low level RF feedback has been added to the cavity control in both rings.
IHEP Beijing, Beijing
IHEP Beiing, Beijing
As a tau-charm factory like collider, the upgrade project of the Beijing Electron Positron Collider (BEPCII), has reached its first design value of luminosity. During the commissioning of its luminosity, beam optics recovery, machine parameters measurement, detector solenoid compensation, and instability cure are main problems we met. Besides commissioning the machine, beams were delivered to the users from high energy physics and synchrotron radiation. This paper summarizes the accelerator physics issues in the BEPCII luminosity commissioning.
Supported by National Natural Sciences Foundation of China (10725525)
Fermilab, Batavia
Muon collider is a promising candidate for the next energy frontier machine. However, in order to obtain peak luminosity in the 1035/cm2/s range the collider lattice design must satisfy a number of stringent requirements, such as low beta at IP (beta*<1 cm), large momentum acceptance and dynamic aperture and small value of the momentum compaction factor. Here we present a particular solution for the interaction region optics whose distinctive feature is a three-sextupole local chromatic correction scheme. Together with a new flexible momentum compaction arc cell design this scheme allows to satisfy all the above-mentioned requirements and is relatively insensitive to the beam-beam effect.
Fermilab, Batavia
JINR, Dubna, Moscow Region
Design of a muon collider interaction region (IR) presents a number of challenges arising from low beta* < 1 cm, correspondingly large beta-function values and beam sizes at IR magnets, as well as the necessity to protect superconducting magnets and collider detectors from muon decay products. As a consequence, the designs of the IR optics, magnets and machine-detector interface are strongly interlaced and iterative. A consistent solution for the 1.5 TeV c.o.m. muon collider IR is presented. It can provide an average luminosity of 1034/cm2/s with an adequate protection of magnet and detector components.
Muons, Inc, Batavia
To achieve the high luminosity required for a muon collider strong quadrupole magnets will be needed for the final focus in the interaction region. These magnets will be located in regions with space constraints imposed both by the lattice and the collider detector. There are significant beam related backgrounds from muon decays and synchrotron radiation which create unwanted particles which can deposit significant energy in the magnets of the final focus region of the collider. This energy deposition results in the heating of the magnet which can cause it to quench. To mitigate the effects of heating from the energy deposition shielding will need to be included within the magnet forcing the aperture to be larger than desired and consequently reducing the gradient. We propose to use exotic high magnetization materials for pole tips to increase the quadrupole gradient.
MPI-P, München
IHEP Beijing, Beijing
Simulations of frictional cooling for a muon collider front end scheme show that it is a viable technique for quickly producing colliding beams. The Frictional Cooling Demonstration experiment at the Max Planck Institute for Physics, Munich, aims to demonstrate the working principle of frictional cooling on protons using a 10-cm-long cooling cell. The experiment is nearing the final data taking stages. The status of the experiment is presented along with recent data. Simulation of the experiment setup is also presented.
MPI-P, München
IHEP Beijing, Beijing
Muon colliders would open new frontiers of investigation in high energy particle physics, allowing precision measurements to be made at the TeV energy frontier. One of the greatest challenges to constructing a muon collider is the cooling of a beam of muons on a timescale comparable to the lifetime of the muon. Frictional cooling holds promise for use in a muon collider scheme. By balancing energy loss to a gas with energy gain from an electric field, a beam of muons is brought to an equilibrium energy in 100s of nanoseconds. A frictional cooling scheme for producing high-luminosity beams for a muon collider is presented.
CASA, newport news
JLAB, Newport News, Virginia
The proposed electron collider lattice exhibits low β- functions at the Interaction Point (IP) (βx∗100mm − βy∗ 20 mm) and rather large equilibrium momentum spread of the collider ring (δp/p = 0.00158). Both features make the chromatic corrections of paramount importance. Here the chromatic effects of the final focus quadruples are cor- rected both locally and globally. Local correction features symmetric sextupole families around the IP, the betatron phase advances from the IP to the sextupoles are chosen to eliminate the second order chromatic aberration. Global interleaved families of sextupoles are placed in the figure-8 arc sections, and non-interleaved families at straight sec- tion making use of the freely propagated dispersion wave from the arcs. This strategy minimizes the required sex- tupole strength and eventually leads to larger dynamic aper- ture of the collider. The resulting spherical aberrations induced by the sextupoles are mitigated by design; the straight and arc sections optics features an inverse identity transformation between sextupoles in each pair.
Muons, Inc, Batavia
Illinois Institute of Technology, Chicago, Illinois
There are dozens of programs for designing and modeling accelerator systems, most of which have their own language for describing the system. This means a designer must spend considerable time learning the languages of different programs and converting system descriptions among them. This paper describes a project to develop a new language for accelerator modeling, together with a portable suite of programs to implement it. These programs will assist the user while editing, visualizing, developing, simulating, and sharing models of accelerator components and systems. This suite is based on a Graphical User Interface (GUI) that will permit users to assemble their system graphically and then display it and check its sanity visually, even while using modeling programs that have no graphical or visualization capabilities. Incorporating the concept of libraries as a primary component of the language will encourage collaboration among geographically diverse teams. The requirements for developing this language and its tools will be based on generality, flexibility, extensibility, portability, usability, and sharability.
Muons, Inc, Batavia
Illinois Institute of Technology, Chicago, Illinois
The G4beamline program* is a useful and steadily improving tool to quickly and easily model beam lines and experimental equipment without user programming. It has both graphical and command-line user interfaces. Unlike most accelerator physics codes, it easily handles a wide range of materials and fields, being particularly well suited for the study of muon and neutrino facilities. As it is based on the Geant4 toolkit**, G4beamline includes most of what is known about the interactions of particles with matter. We are continuing the development of G4beamline to facilitate its use by a larger set of beam line and accelerator developers. A major new feature is the calculation of space-charge effects. G4beamline is open source and freely available at: http://g4beamline.muonsinc.com
* http://g4beamline.muonsinc.com
** http://geant4.cern.ch
BNL, Upton, Long Island, New York
Future projects for electron-hadron colliders will be reviewed. Existing designs will be presented and, when possible, compared. The challenges and required R&D program will be discussed.
KEK, Ibaraki
The beam extraction experiment using the strip-line kicker has been carried out at KEK-ATF. The specification of the International linear collider (ILC) is that the long bunch train (1320 - 5120 bunches), which has the bunch spacing of 189 - 480ns, is compressed to 3 or 6ns bunch spacing into the DR, and again decompressed from the DR. The kicker manipulates the changes of the bunch spacing. The kicker requires a fast rise/fall time (3 or 6ns) and a high repetition rate (3 or 6MHz). A multiple strip-line kicker system is the most promising candidate to realize the specification for the ILC*. The beam extraction experiment at KEK-ATF** using proto-type of the strip-line kicker was done by following parameters, up to 30 bunches of the multi-bunch in the DR, which has 5.6ns bunch spacing, are extracted bunch-by-bunch with 308ns interval to the extraction line. The stored multi-bunch was extracted successfully. The detail of the experiment and the result are reported.
* T. Naito et. al., Proc. of PAC07, pp2772-2274.
** T. Naito et. al., Proc. of EPAC08, pp601-603.
Tohoku University, Graduate School of Science, Sendai
KEK, Ibaraki
Tohoku University, School of Scinece, Sendai
We have studied a beam orbit tilt monitor for stabilizing the beam orbit in ATF2. Once we can measure a beam orbit tilt with high precision at one point, we can relate this data with the beam position profile at the focal point. A tilt monitor is composed of a single rectangular sensor cavity and a waveguide to extract the signal. In the sensor cavity, there is the most basic resonant mode called monopole mode. This monopole mode is perpendicular to the nominal beam axis, and excited by the beam tilt. We extract this monopole mode. As the result, the amplitude of the extracted signal is proportional to the tilt angle. The tilt monitor is almost indepnedent with beam postion, so we can get the tilt date independently. According to our simulation, the sensitivity is estimated about 35nrad in the vertical direction. The prototype was completed and installed in the test area on the ATF2 beamline. The first beam test will be performed in December 2009. We will report this result and future update plan.
I-Tech, Solkan
After LHC completion, maintenance and operation of the facility provide a good opportunity for accelerator industry in Europe. Other big facilities like XFEL, FAIR, FERMI@ELETTRA and MAX IV are now under way. The challenges of the accelerator industry in Europe and its future outlook will be presented.
JAI, Oxford
We present the design and beam test results of a prototype beam-based digital feedback system for the Interaction Point of the International Linear Collider. A custom analogue front-end signal processor, FPGA-based digital signal processing boards, and kicker drive amplifier have been designed, built, deployed and tested with beam in the extraction line of the KEK Accelerator Test Facility (ATF2). The system was used to provide orbit correction to the train of bunches extracted from the ATF damping ring. The latency was measured to be approximately 140 ns.
KEK, Ibaraki
Akita University, Akita
Profile shape measurements detecting profile slope angle, which corresponds to the differential of the profile shape, have been used for evaluating profile shapes highly precisely. They are hardly affected by scanning error in measurement and considered to have advantages for long distance measurements. Here, profile measurement using a level was adopted for straightness alignment of the KEK e-/e+ injector linac, considering the straightness alignment as a profile shape measurement. The slope angles between the alignment base plates of the linac could be detected with reproducibility of 10 micro-rad (σ) by sequential measurement interval of 1 to 2 m. The reproducibility of the straightness derived from the angle measurements was 42 micrometer (σ) for 69 m of the measurement distance and agreed well with the estimated value based on our error propagation model. These results show that straightness reproducibility of better than 1 mm (2-σ) can be achieved for 500 m of the KEK e-/e+ injector linac by sampling interval of 2m, and for 10 km of the ILC linac by sampling interval of 20 cm.
University of Cassino, Cassino
INFN-Pisa, Pisa
The possible issues related to the use of last-generations Insulated Gate Bipolar Transistors (IGBTs) switches into a Marx-topology klystron modulator are discussed. Experimental results obtained from two cells Marx prototypes using two different solutions, including single device and series connected devices both hard-switched, are presented. The use of single high voltage device per cell allowed us to obtain lower on-state voltage drop but much slower switching times. On the other side the series connection of lower voltage IGBTs results in much faster commutations and lower devices costs accompanied by a larger on state voltage drop.
JINR, Dubna, Moscow Region
The investigations on ILC siting in the Dubna region and ILC technical activity at JINR are presented. International intergovernmental status of JINR, stable geological and plain relief conditions, comfortable location and well developed infrastructure create a set of advantages of the JINR site in the neighborhood of Dubna. The shallow layout of accelerator tunnel makes it possible to use a communication gallery at the surface instead of second one. This is an effective way of significant cost reduction of all conventional facilities and explicit labor of the project. The results of the preliminary geological engineering surveys along the supposed route of the ILC in Dubna area of Moscow region are presented.
CERN, Geneva
Fermilab, Batavia
High-energy accelerators are large projects funded by public money, developed over the years and constructed via major industrial contracts both in advanced technology and in more conventional domains such as civil engineering and infrastructure, for which they often constitute one-off markets. Assessing their cost, as well as the risk and uncertainty associated with this assessment is therefore an essential part of project preparation and a justified requirement by the funding agencies. Stemming from the experience with large circular colliders at CERN, LEP and LHC, as well as with the Main Injector, the Tevatron Collider Experiments and Accelerator Upgrades, and the NOvA Experiment at Fermilab, we discuss sources of cost variance and derive cost risk assessment methods applicable to the future linear collider, through its two technical approaches for ILC and CLIC. We also address disparities in cost risk assessment imposed by regional differences in regulations, procedures and practices.
ANL, Argonne
Euclid TechLabs, LLC, Solon, Ohio
In this paper, we present a linear collider concept based on drive beam generation from an RF photoinjector, and employing dielectric structures for power extraction and acceleration. The collider is based on a modular design with each module providing 100 GeV net acceleration. A high current drive beam is produced using a low frequency RF gun (~ 1GHz), and subsequently accelerated to ~1 GeV using conventional standing wave cavities. High frequency (20 GHz) RF power, extracted from the drive beam using a low impedance dielectric structure, is used to power the main linacs, which are based on high impedance high gradient dielectric loaded accelerating structures. We envision this scheme will produce high gradients (300 MeV/m), leading to a very compact design. The modularity of the design will allow a staged construction that will enable extension to multi-TeV energies.
LLNL, Livermore, California
SLAC, Menlo Park, California
The realization of a photon collider option at a future TeV scale electron linear collider requires the generation of high average power picosecond laser pulses. Recirculating cavities have been proposed to reduce the amount of laser power that needs to be generated, however, these cavities impose stringent limits on the wavefront quality and stability of the laser architecture. We report on a design study of a high average power laser amplifier architecture which can produce the required laser time structure and stability to drive these recirculating cavities.
BNL, Upton, Long Island, New York
LAL, Orsay
IN2P3-LAPP, Annecy-le-Vieux
OXFORDphysics, Oxford, Oxon
CERN, Geneva
KEK, Ibaraki
SLAC, Menlo Park, California
The KEK ATF2 facility, with a well instrumented beam line and Final Focus (FF), is a proving ground for linear collider (LC) technology to demonstrate the extreme beam demagnification and spot stability needed for a LC FF*. ATF2 uses water cooled magnets but the baseline ILC calls for a superconducting FF**. Thus we plan to replace some ATF2 FF magnets with superconducting ones made via direct wind construction as planned for the ILC. With no cryogenic supply at ATF2, we look to cool magnets and current leads with a few cryocoolers. ATF2 FF coil winding is underway at BNL and production warm magnetic measurements indicate good field quality. Having FF magnets with larger aperture and better field quality than present FF might allow reducing the beta function at the FF for study of focusing regimes relevant to CLIC. Our ATF2 magnet cryostat will have laser view ports for cold mass movement measurement and FF support and stabilization requirements under study. We plan to make stability measurements at BNL and KEK to relate ATF2 FF magnet performance to that of a full length ILC R&D prototype at BNL. We want to be able to predict LC FF performance with confidence.
* ATF2 proposal, volumes 1 and 2 at http://lcdev.kek.jp/ILC-AsiaWG/WG4notes/atf2/proposal/index.html
** International Linear Collider Reference Design Report, ILC-REPORT-2007-001, August 2007.
Imperial College of Science and Technology, Department of Physics, London
Muon ionization cooling provides the only practical solution to prepare high brilliance beams necessary for a neutrino factory or muon colliders. The muon ionization cooling experiment (MICE)* is under development at the Rutherford Appleton Laboratory (UK). It comprises a dedicated beam line to generate a range of input emittance and momentum, with time-of-flight and Cherenkov detectors to ensure a pure muon beam. A first measurement of emittance is performed in the upstream magnetic spectrometer with a scintillating fiber tracker. A cooling cell will then follow, alternating energy loss in liquid hydrogen and RF acceleration. A second spectrometer identical to the first one and a particle identification system provide a measurement of the outgoing emittance. In May 2010 it is expected that the beam and most detectors will be commissioned and the time of the first measurement of input beam emittance closely approaching. The plan of steps of measurements of emittance and cooling, that will follow in the rest of 2010 and later, will be reported.
This abstract is submitted by the chear of the MICE speaker bureau. A member of the collaboration will be soon identified to present the poster and added a co-author.
Fermilab, Batavia
BNL, Upton, Long Island, New York
IIT, Chicago, Illinois
LBNL, Berkeley, California
An accelerator complex that can produce ultra-intense beams of muons presents many opportunities to explore new physics. A facility of this type is unique in that, in a relatively straightforward way, it can present a physics program that can be staged and thus move forward incrementally, addressing exciting new physics at each step. At the request of the US Department of Energy's Office of High Energy Physics, the Neutrino Factory and Muon Collider Collaboration and the Fermilab Muon Collider Task Force have recently submitted a proposal to create a Muon Accelerator Program that will have, as a primary goal, to deliver a Design Feasibility Study for an energy-frontier Muon Collider after a 7 year R&D program. This paper presents a description of a Muon Collider facility with a brief physics motivation, gives an overview of the proposal with respect to its organization and timeline and then discusses in some detail its major technical components.
Fermilab, Batavia
Imperial College of Science and Technology, Department of Physics, London
To demonstrate the feasibility of a high pressure RF cavity for use in the cooling channel of a muon collider, an experimental setup that utilizes 400-MeV Fermilab linac proton beam has been developed. In this paper, we describe the beam diagnostics and the collimator system for the experiment, and report the initial results of the beam commissioning. The transient response of the cavity to the beam is measured by the electric and magnetic pickup probes, and the beam-gas interaction is monitored by the optical diagnostic system composed of a spectrometer and two PMTs.
Fermilab, Batavia
ANL, Argonne
Ionization cooling is a critical building block for the realization of a muon collider. To suppress breakdown in the presence of the external magnetic field, an idea of using an RF cavity filled with high pressure hydrogen gas is being considered for the cooling channel design. In the high pressure RF cavity, ionization energy loss and longitudinal momentum recovery can be achieved simultaneously. One possible problem expected in the high pressure RF cavity is, however, the dissipation of significant RF power through the electrons accumulated inside the cavity. The electrons are generated from the beam-induced ionization of the high pressure gas. To characterize this detrimental loading effect, we develop a simplified model that relates the electron density evolution and the observed pickup voltage signal in the cavity, with consideration of several key molecular processes such as the formation of the polyatomic molecules and ions, excitation, recombination and electron attachment. This model is expected to be compared with the actual beam test of the cavity in the MuCool Test Area (MTA) of Fermilab.
Muons, Inc, Batavia
Northern Illinois University, DeKalb, Illinois
Muon Colliders produce high rates of unwanted particles near the beams in the detector regions. Previous designs have used massive shielding to reduce these backgrounds, at a cost of creating dead regions in the detectors. To optimize the physics from the experiments, new ways to instrument these regions are needed. Since the last study of a muon collider detector in the 1990s, new types of detectors, such as solid state photon sensors that are fine-grained, insensitive to magnetic fields, radiation-resistant, fast, and inexpensive have become available. These can be highly segmented to operate in the regions near the beams. We re-evaluate the detector design, based on new sensor technologies. Simulations that incorporate conditions in recent muon collider interaction region designs are used to revise muon collider detector parameters based on particle type and occupancy. Shielding schemes are studied for optimization. Novel schemes for the overall muon collider design, including "split-detectors", are considered.
Muons, Inc, Batavia
Fermilab, Batavia
A helical cooling channel (HCC) consisting of a pressurized gas absorber imbedded in a magnetic channel that provides solenoidal, helical dipole and helical quadrupole fields has shown considerable promise in providing six-dimensional cooling for muon beams. The energy lost by muons traversing the gas absorber needs to be replaced by inserting RF cavities into the HCC lattice. Replacing the substantial muon energy losses using RF cavities with reasonable gradients will require a significant fraction of the channel length be devoted to RF. However to provide the maximum phase space cooling and minimum muon losses, the HCC should have a short period and length. In this paper we examine an approach where each HCC cell has an RF cavity imbedded in the aperture with the magnetic coils are split allowing for half of the cell length to be available for the RF coupler and other services.
Muons, Inc, Batavia
Fermilab, Batavia
Intense muon beams have many potential applications, including neutrino factories and muon colliders. However, muons are produced as tertiary beams, resulting in diffuse phase space distributions. To make useful beams, the muons must be rapidly cooled before they decay. An idea conceived recently for the collection and cooling of muon beams, namely, the use of a Quasi-Isochronous Helical Channel (QIHC) to facilitate capture of muons into RF buckets, has been developed further. The resulting distribution could be cooled quickly and coalesced into a single bunch to optimize the luminosity of a muon collider. After a brief elaboration of the QIHC concept, some recent developments are described.
UCLA, Los Angeles, California
RadiaBeam, Marina del Rey
One of the challenges of the proposed muon collider is the beam size at the interaction region. The current target for the beta function (beta-star) is 10mm for the 1.5TeV scenario with a beam emittance of 25mm-mrad. In this paper, we describe the design and development of a final focusing scheme that attempts to reach these parameters. The final focus scheme is based on the use of permanent magnet quadrupoles (PMQ) in a triplet configuration. Initial simulations show that the PMQs reach gradients as high as ~990T/m using Praseodymium based magnets in a Halbach style arrangement. Possible methods for tuning the PMQs at the interaction region, via temperature control and high-resolution movers, are also described.
PU, Princeton, New Jersey
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
STFC/RAL, Chilton, Didcot, Oxon
ORNL, Oak Ridge, Tennessee
CERN, Geneva
EBG MedAustron, Wr. Neustadt
BNL, Upton, Long Island, New York
Fermilab, Batavia
PPPL, Princeton, New Jersey
We report on the analysis of data collected in the MERIT experiment at CERN during the Fall of 2007. These results validate the concept of a free mercury jet inside a high-field solenoid magnet as a target for a pulsed proton beam of 4-MW power, as needed for a future Muon Collider and/or Neutrino Factory.
UCR, Riverside, California
A significant reduction in the six-dimensional emittance of the initial beam is required in any proposed Muon Collider scheme. Two lattices based on the original RFOFO ring design representing different stages of cooling are considered. One is the so-called open cavity lattice addressing the problem of the 201.25 MHz RF cavities running in a magnetic field, the other one is the 805 MHz RF lattice that is used for smaller emittances. The details of the acceptance analysis and tracking studies of both channels are presented and compared to the independent ICOOL implementation.
Euclid TechLabs, LLC, Solon, Ohio
LETI, Saint-Petersburg
CERN, Geneva
In this presentation, dielectric collimator concepts for the linear collider will be described. Cylindrical and planar dielectric collimator designs for CLIC and ILC parameters will be presented, and results of simulations to minimize the beam impedance will be discussed. The prototype collimator system is planned to be fabricated and experimentally tested at Facilities for Accelerator Science and Experimental Test Beams (FACET) at SLAC.
BNL, Upton, Long Island, New York
University of Warwick, Coventry
STFC/RAL, Chilton, Didcot, Oxon
UCLA, Los Angeles, California
ORNL, Oak Ridge, Tennessee
SUNY SB, Stony Brok, New York
PU, Princeton, New Jersey
We outline a program of engineering design and simulation for a target station and pion production/capture system for a 4-MW proton beam at the front end of a Muon Collider or a Neutrino Factory. The target system consists of a free liquid-metal (nominally mercury) jet immersed in a high-field solenoid magnet capture system that also incorporates the proton beam dump. Topics to be studied include optimization of proton beam and jet target parameters, of the magnetic configuration for capture and subsequent transport of pions and muons, of the beam dump, of the radiation/thermal shielding of the capture magnets, and of the beam windows.
INFN/LNF, Frascati (Roma)
To achieve luminosities significantly higher than in existing machines, future storage-ring based colliders will need to operate in novel parameter regimes combining ultra-low emittance, large Piwinski angle and high bunch charge; implementation of techniques such as a "crab waist" will add further challenges. Understanding the beam-beam interaction in these situations will be essential for the design of future very high luminosity colliders. Recent developments in modeling tools for studying beam-beam effects, capable of investigating the relevant regimes, will be discussed and examples, including tests with crab waist collisions in DAΦNE, will be presented.
TUB, Beijing
Since being introduced to accelerator physics, I have had the privilege to study and work with some of the best physicists on some of the most exciting projects. My first assignment was to simulate transition-crossing in RHIC in which a shocking 86% beam loss led to a redesign of its RF system which later earned me a Ph.D. Participation in the design, R&D, construction, and the commissioning of RHIC, not only was I introduced to the fascinating world of accelerator physics but was also trained as a physicist for accelerator projects. Since then, I have had the opportunity to work and lead teams of physicists and engineers on accelerator projects: US-LHC/AP at BNL, SNS/AP at ORNL, SNS ring, CSNS in China, and now CPHS at Tsinghua. The accelerator profession is uniquely rewarding in that ideas and dreams can be turned into reality through engineering projects, through which one experiences endless learning in physics, technology, teamwork and friendship. An example of enjoying the fun and friendship is the work on crystalline beams as a hobby for the past 18 years.
*Wei, Li, Sessler, Okamoto PRL73(94)3089; 80(98)2606
*Wei, Harrison XVI RCNP Osaka(97)
*Wei et al PAC99 2921
*Wei et al PAC01(01)319
*Wei RMP75(03)1383
*Wei et al NIMA600(09)10
*Wei et al PAC09
CERN, Geneva
I will briefly describe CERN's colliders starting with the ISR, going through LEP, and finishing with the LHC. The common threads will be discussed in terms of people and techniques. I will start by describing the incredible impact on accelerator physics of the almost forgotten, first ever hadron collider, the ISR. I will then present the construction and 12 years of operation of LEP. Finally I will also provide the first results of beam operation in the LHC as well as the plans for the near and far future.
KEK, Ibaraki
SLAC, Menlo Park, California
CERN, Geneva
A CERN-SLAC-KEK collaboration on high gradient X-band accelerator structure development for CLIC has been ongoing for three years. The major outcome has been the demonstration of stable 100 MV/m gradient operation of a number of CLIC prototype structures. These structures were fabricated basically using the technology developed from 1994 to 2004 for the GLC/NLC linear collider initiative. One goal has been to refine the essential parameters and fabrication procedures needed to realize such high gradient routinely. Another goal has been to develop structures with stronger dipole mode damping than those for GLC/NLC. The latter requires that surface temperature rise during the pulses be higher, which may increase the breakdown rate. Structures with heavy damping will be tested in late 2009/early 2010, and this paper will present these results together with some of the earlier results from non-damped structures and structures built with a quadrant geometry.
Fermilab, Batavia
Muons, Inc, Batavia
Alternative RF cavity fabrication techniques for accelerator applications at low frequencies are needed to improve manufacturability, reliability and cost. RF cavities below 800 MHz are large, take a lot of transverse space, increase the cost of installation, are difficult to manufacture, require significant lead times, and are expensive. Novel RF cavities partially loaded with a ceramic for accelerator applications will allow smaller diameter cavities to be designed and built. The manufacturing techniques for partially loaded cavities will be explored. A new 200MHz cavity will be built for the Fermilab Proton Source to improve the longitudinal emittance and energy stability of the linac beam at injection to the Booster. A cavity designed for 400 MHz with a ceramic cylinder will be tested at low power at cryogenic temperatures to test the change in Qo due to the alumina ceramic. Techniques will be explored to determine if it is feasible to change the cavity frequency by replacing an annular ceramic insert without adversely effecting high power cavity performance.
CUT, Krakow
The array of corrector magnets in the LHC is powered by means of a superconducting line attached to the main magnets. The subcooling time of the line has to be minimized in order not to delay the operation of the collider. The corresponding cable-in-conduit problem is formulated in the framework of two-fluid model and the Gorter-Mellink law of heat transport in superfluid helium. A model of λ front propagation along the narrow channel containing superconductors and liquid helium is presented. The one-dimensional model* adopts plane wave equations to describe λ front propagation. This approach to normal-to-superfluid phase transition in liquid helium allows to calculate the time of subcooling and the temperature profile on either side of the travelling front in long channels containing superconducting bus-bars. The model has been verified by comparing the analytical solutions with the experimental results obtained in the LHC String 2 experiment. The process of the LHC Dispersion Suppressors subcooling has been optimized by using the presented model. Based on the results, a novel concept of copper heat exchanger for LHC DS operating in superfluid helium is introduced.
* M. Sitko, B. Skoczeń, Modelling HeI-HeII phase transformation in long channels containing superconductors, Int. Journal of Heat and Mass Transfer, Vol. 52, Issues 1-2,pp. 9-16, 2009.
CERN, Geneva
The operation of the LHC imposes minimum maintenance time, when needed corrections to all systems are to be carried out. Today's maintenance management tools at CERN are seen as too slow and cumbersome for such a challenge. The short duration of the technical stops (72 h/month) requires preparation of jobs in advance, and coordination of all involved teams; at the same time, the radio-protection of personnel in the LHC underground areas imposes a strict "As Low As Reasonably Achievable"(ALARA) policy for the works' duration. In order to perform a maximum of tasks in a short time, a mobile tool for the manipulation of job and equipment data has been created. The ability to signal a new job to a team in the field will avoid unnecessary trips to the tunnel; the signaling of a job's completion (and its details) will allow subsequent jobs to start promptly and with more information; finally, the possibility to consult equipment's full manufacturing and installation data "in situ" will help with the investigation of unforeseen situations. In a 27 km environment with scarce Wi-Fi connectivity, an online light tool is now available, covering the essentials of asset maintenance tasks.
CERN, Geneva
JINR, Dubna, Moscow Region
A number of tests were performed by the UA9 Collaboration* in the North area of the SPS in view of investigating crystal-particles interactions for future application in hadron colliders. The rate of nuclear reactions was measured with 400 GeV proton beams directed into a silicon bent crystal. In this way the background induced by the crystal itself either in amorphous or in channeling orientation was revealed. The results provide fundamental information to put in perspective the use of silicon crystals to assist halo collimation in hadron colliders, whilst minimizing the induced loss. Crystals made of Germanium were also investigated in view of the expected increase of the collimation efficiency respect to silicon. Finally, crystals were tested in axial orientation and with incoming particles of negative charge. The collected results are presented in details.
* http://greybook.cern.ch/programmes/experiments/UA9.html
Muons, Inc, Batavia
Fermilab, Batavia
The designs of accelerator systems that will be needed to transform Fermilab's Project X into a high-power proton driver for a muon collider and/or a neutrino factory are discussed. These applications require several megawatts of beam power delivered in tens or hundreds of short multi-GeV bunches per second, respectively. Project X may require a linac extension to higher energy for this purpose. Other major subsystems that are likely to be needed include storage rings to accumulate and shorten the proton bunches and an external beam combiner to deliver multiple bunches simultaneously to the pion production target.
Fermilab, Batavia
Beam collisions with a crossing angle at the interaction point are often necessary in colliders to reduce the effects of parasitic collisions which induce emittance growth and decrease beam lifetime. The crossing angle reduces the geometrical overlap of the beams and hence the luminosity. Crab cavity offer a promising way to compensate the crossing angle and to realize effective head-on collisions. Moreover, the crab crossing mitigates the synchro-betatron resonances due to the crossing angle. A crab cavity experiment in SPS is proposed as a proof of principle before deciding on a full crab-cavity implementation in the LHC. In this paper, we investigate the effects of a single crab cavity on beam dynamics in the SPS and life time.
BNL, Upton, Long Island, New York
Electron lenses for the head-on beam-beam compensation are under construction at the Relativistic Heavy Ion Collider. The bunch length is of the same order as the beta-function at the interaction point, and a proton passing through another proton bunch experiences a substantial phase shift which modifies the beam-beam interaction. We review the effect of the bunch length in the single pass beam-beam interaction, apply the same analysis to a proton passing through a long electron lens, and study the single pass beam-beam compensation with long bunches.
CERN, Geneva
The CLIC study is a site independent study exploring technological developments to extend linear colliders into the Multi-TeV colliding beam energy range at reasonable cost and power consumption. A conceptual design report (CDR) of an electron-positron Compact LInear Collider (CLIC) with a 3 TeV center-of-mass collision energy is presently being prepared including results of 25 years of R&D to address the feasibility of its novel and promising technology, especially in an ambitious Test Facility, CTF3. The R&D is performed by a multi-lateral CLIC/CTF3 collaboration strong of 37 volunteer institutes from 19 countries from which the outstanding work and results are reported.