THALES, Colombes
CEA, Arpajon
CLIO/ELISE/LCP, Orsay
Inverse Compton scattering is a well-known process to produce X-rays. Thanks to recent progress in accelerators and laser field, such sources have been developed worldwide. The ELSA linear electron accelerator (CEA DAM DIF, Arpajon, France) just developed its own source. The 17 MeV electron beam interacts with a 532 nm laser to provide a pulsed 10 keV X-ray source. The X-ray beam profile is observed on radio-luminescent imaging plates. In order to increase the signal to noise ratio of this X-ray source, laser developments are in progress.
Manchester University, Manchester
UMAN, Manchester
University of Huddersfield, Huddersfield
Thorium fueled Accelerator Driven Subcritical Reactors have been proposed as a more comprehensive alternative to conventional nuclear reactors for both energy production and for burning radioactive waste. Several new classes have been added by the authors to the GEANT4 simulation code, extension which allows the state-of-the-art code to be used for the first time for nuclear reactor criticality calculations. In this paper we investigate the impact of the subcriticality and injected proton beam energy on the ADSR performance for novel ADSR configurations involving multiple accelerator drivers and associated neutron spallation targets within the reactor core.
KEK, Ibaraki
JAI, Egham, Surrey
INPR, Tomsk
TPU, Tomsk
RISE, Tokyo
High-brightness and reliable sources in the VUV and the soft X-ray region may be used for numerous applications in such areas as medicine, biology, biochemistry, material science, etc. 4th generation light sources based on X-ray free electron lasers are being built in a few world's leading laboratories. However, those installations are very expensive and the access to wider community is very limited. We propose a new approach to produce the intense beams of X-rays in the range of less than 500 eV based on compact electron accelerator. An ultimate goal of the project is to create a compact soft X-ray source based on Thomson scattering of Coherent Diffraction Radiation (CDR) using a small accelerator machine. CDR is generated when a charged particle moves in the vicinity of an obstacle. The radiation is coherent when its wavelength is comparable to or longer than the bunch length. The CDR waves will be generated in an opened resonator formed by two mirrors. In this report we represent the status of the experiment. The pilot experimental results and general hardware design will be demonstrated.
The University of Tokyo, Tokyo
RAPID (Rutherford Backscattering Spectroscopic Analyzer with Particle Induced X-ray Emission and Ion Implantation Devices), the University of Tokyo has been dedicated to various scientific and engineering studies in a wide range of fields by the ion beam analysis availability, including RBS, NRA, PIXE and ion implantation. The system consists of a 1.7MV tandem accelerator (Model 4117-HC,provided by HVEE corp., Netherland), two negative ion sources (a Cs sputter solid ion source and duoplasmatron gas ion source) and three beam lines. RAPID was installed in 1994 at Research Center for Nuclear Science and Technology, the University of Tokyo at first and since then it has been used for various research fields using ion beams. As the Center was reorganized to be a department of School of Engineering in 2005, the educational utilization came to be an important mission of RAPID. Besides several application studies with PIXE analysis, environmental analysis (pond sediments and atmospheric SPM (Suspended Particulate Matter) is performed as a student experiment. Recently, a low level ion irradiation system was also developed and applied for the study of CR-39 track detector with proton beam.
University of Huddersfield, Huddersfield
Manchester University, Manchester
The European Spallation Source (ESS) is one of Europe's biggest and most prestigious science projects to design and construct the next generation facility for research with neutrons. ESS will be the world's most powerful spallation source and it will provide a unique tool for research into the atomic structure and dynamics of matter. We investigate the effects of the dimensions of the ESS spallation target on the total neutron yield integrated over the neutron energy and emission angle. We also investigate different material choices for the ESS target.
FEL/Duke University, Durham, North Carolina
Compton scattering of a laser beam with a relativistic electron beam has been used to generate an intense, highly polarized, and nearly monoenergetic gamma-ray beam at several facilities. The ability of predicting the spatial and spectral distributions of a Compton gamma-ray beam is crucial for the optimization of the operation of a Compton light source as well as for the applications utilizing the Compton beam. Based upon the Lorentz invariant Compton scattering cross section, we have derived an analytical formula to study the Compton scattering process. Using this formula, we have developed an integration code to produce the smooth results for the spatial and spectral distributions of the Compton beam. This code has been characterized at the High Intensity Gamma-ray Source (HIGS) facility at Duke University for varying electron and laser beam parameters as well as different gamma-ray beam collimation conditions.
IUCF, Bloomington, Indiana
IUCMB, Bloomington, Indiana
We are building a low energy electron storage ring that has many desirable properties, such as varying momentum compaction factor, damping partition numbers, favorable betatron tunes for multiturn accumulations, and excellent dynamic aperture. This storage ring can be used for debunching rf linac beams in one turn, for compression of linac pulses, and more importantly for a compact photon source based on inverse Compton scattering of laser beams.
KEK, Ibaraki
LBNL, Berkeley, California
Osaka University, Osaka
OXFORDphysics, Oxford, Oxon
Liquid hydrogen absorbers for the Muon Ionization Cooling Experiment (MICE) have been developed, and the first absorber has been tested at KEK. In the preliminary test at KEK we have successfully filled the absorber with ~2 liters of liquid hydrogen. The measured hydrogen condensation speed was 2.5 liters/day at 1.0 bar. No hydrogen leakage to vacuum was found between 300 K and 20 K. The MICE experiment includes three AFC (absorber focusing coil) modules, each containing a 21 liter liquid hydrogen absorber made of aluminum. The AFC module has safety windows to separate its vacuum from that of neighboring modules. Liquid hydrogen is supplied from a cryocooler with cooling power 1.5 W at 4.2 K. The first absorber will be assembled in the AFC module and installed in MICE at RAL.
Kyoto ICR, Uji, Kyoto
ILL, Grenoble
RID, Delft
ANL, Argonne
KURRI, Osaka
RIKEN, Wako, Saitama
ANSTO, Menai
KEK, Ibaraki
We have developed a motorized magnetic lens for focusing of pulsed white neutron beams. The lens is composed of two concentric permanent magnet arrays, in sextupole geometry, with bore of 15 mm and magnet length of 66 mm. The inner magnet array is stationary, while the outer array is rotated (the frequency of the modulation of magnetic field inside the bore ν ≤ 25Hz), providing a sextupole magnetic field gradient range of 1.5x104T/m2 ≤ g' ≤ 5.9x104T/m2. By synchronization of a pulsed neutron beam with the sinusoidal modulation of the magnetic field in the lens, the beam is focused, without significant chromatic aberration, over a wide neutron wavelength band. We have constructed a focusing-SANS (Small Angle Neutron Scattering) test bed on the PF2-VCN (Very Cold Neutron) beam line at the Institut Laue-Langevin in Grenoble. The beam image size matched the source size (≈ 3mm) over of wavelength range of 30Å ≤ λ ≤ 48Å with focal length of ~ 2.3 m. Further, we have demonstrated the performance of this device for high resolution time-of-flight (tof) SANS for a selection of polymeric & biological samples, in a compact geometry of just 5 m.
W.C. Heraeus GmbH, Materials Technology Dept., Hanau
Plansee Metall GmbH, Reutte
TU Darmstadt, Darmstadt
DESY, Hamburg
The RRR value of high pure Nb is showing strong relations to the individual production steps. Mainly the different kind of internal stresses caused by the several production steps are resulting in the variation of the RRR value. This work shows the RRR values along the complete production chain from the molten Ingot till to the finished cavity. The influence of the RRR value caused by stresses and the release of that stresses by vacuum annealing is shown.
STFC/RAL/ISIS, Chilton, Didcot, Oxon
The ISIS Facility at the Rutherford Appleton Laboratory in the UK produces intense neutron and muon beams for condensed matter research. The accelerator facility consists of a 70 MeV H- linac and a 50 Hz proton synchrotron accelerating up to 3.75x1013 protons per pulse from 70 to 800 MeV, delivering a mean beam power of 0.24 MW. Present upgrade studies are investigating how replacement of the existing linac and increased injection energy could increase beam power in the existing ISIS ring. Such an upgrade would replace one of the oldest sections of the ISIS machine, and with reduced space charge and optimised injection, may allow substantially increased intensity in the ring, perhaps towards the 0.5 MW regime. A critical aspect of such an upgrade would be the new higher energy injection straight. This paper summarises beam dynamics and hardware requirements for 180MeV H- charge exchange injection into ISIS including; optimisation of the injection magnets; requirements for beam dumps and results of stripping foil simulations with estimates of stripping efficiency and foil heating.
Kyoto ICR, Uji, Kyoto
NIRS, Chiba-shi
S-LSR is a compact ion storage and cooler ring to inject beam of the 7MeV proton and the 40MeV Mg+. The average vacuum pressure measured by the vacuum gauges without beam was achieved up to about 4x10-9 Pa in 2007. Many experiments have been carried out using the proton and Mg beam, for example the one-dimensional beam ordering of protons utilizing the electron cooler, the extraction tests of the short bunched beam and the laser cooling for the Mg beam had been performed. The beam lifetime can be estimated with the vacuum pressure or the loss-rate of the beam energy. The values of the estimated lifetime are nearly equal to the measured lifetime values. The present status of the proton beam lifetime and the vacuum pressure is reported.
JAI, Oxford
CERN, Geneva
Pepper-pot based transverse emittance measurement has the advantage of providing a fast (single shot) measurement with a relatively simple hardware. We report on Pepper-pot based transverse emittance measurements made at the CERN Linac 4 test stand.
Diamond, Oxfordshire
University of Oxford, Clarendon Laboratory, Oxford
JAI, Oxford
Single shot emittance measurement is essential to assess the performance of new generation light sources such as linac based X-ray FELs or laser plasma wakefield accelerators. To this aim, we have developed a single shot emittance measurement using at least 3 screens inserted in the beam at the same time, measuring the beam size at different positions in a drift space in one shot. We present here test measurements performed at Diamond in the transfer line from the Booster to the Storage Ring, using thin OTR and also YAG screens. We also compare these measurements with results from the more conventional quadrupole scan method and also measurements using an OTR screen and an assembly of two cameras imaging the beam size and the beam divergence at a point near the waist of the beam. The validity and limits of the new method are discussed in the paper.
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.
TUB, Beijing
The Tsinghua Thomson scattering X-ray source (TTX) has a strict laser-electron synchronization requirement and a comprehensive system structure including dual high-power laser system, RF system and beam diagnostic instruments, etc. Recently, a synchronization and control system is developed to meet these requirements, which includes a laser-RF synchronizer with 100fs time jitter, a FPGA based event generator for laser and RF systems with 250ps time resolution, and an EPICS based control system for system integration and remote monitor and control. The electron bunch arrival time jitter is carefully measured and analyzed with the help of a RF deflecting cavity. This paper reports the development status, technical implementation, and measurement results of the synchronization and control system.
Purdue University, West Lafayette, Indiana
RadiaBeam, Marina del Rey
UCLA, Los Angeles, California
One approach for detecting special nuclear material (SNM) at a distance is to use highly penetrating gamma-rays (>6 MeV) to produce photofission. We are investigating inverse gamma-ray sources (IGS), based on inverse Compton scattering (ICS) of a laser pulse on a relativistic electron bunch. Nearly monochromatic gamma rays with high brightness, very small source size and divergence can be produced in IGS. For the interaction drive laser recirculation it is necessary to meet the repetition rate requirements. Three implementations of laser recirculation are proposed for the interaction drive laser, which can significantly reduce the requirements on the interaction drive laser average power. It is found that the recently demonstrated recirculation injection by nonlinear gating (RING) technique offers unique advantages for beam recirculation in IGS.
INFN-Ferrara, Ferrara
UNIFE, Ferrara
IHEP Protvino, Protvino, Moscow Region
We present an analytical model to calculate the physical quantities of interest experienced by relativistic particles in their motion aligned with periodic complex atomic structures. Classical physics equations and the expansion of periodic functions as a Fourier series have been used for the calculation. This method allows calculating the contribution from all the planes and axes inside the crystal, in contrast to other simulation codes for which the motion is evaluated only on nearest neighbors atomic strings. Based on the calculation technique we have developed the "ECHARM" program, which allows calculating one- and two- dimensional averaged physical quantities of interest. The calculation holds for the main axes of any orthorhombic and tetragonal structures and for any orientation in the cubic structure. To underline the capability of the program, complex structures such as zeolites have been worked out. Based on the "ECHARM" code, simulation of the relativistic particle motion within complex structures has been developed. With this code it is possible to simulate the motion in bent crystal to study planar and axial channeling volume reflection.
BINP SB RAS, Novosibirsk
NSU, Novosibirsk
We consider a technique for electron injection into a cyclic accelerator using the laser wakefield acceleration (LWFA) technique. Accelerators with this type of injector can be used for different purposes due to lower size, cost and low radiation hazard. To use the LWFA technique it is necessary to create a small gas cloud inside the accelerator vacuum chamber. But it leads to the increase of particle losses due to scattering on residual gas atoms. Therefore we propose to use magnesium as evaporated gas because of its high absorbability ' its atoms stick to walls at the first contact. We presented estimations of the LWFA-based injection system parameters, including maximum stored current. The proposed technique looks very prospective for compact accelerators and storage rings.
KEK, Ibaraki
University of Tokyo, Tokyo
Tohoku University, Graduate School of Science, Sendai
SuperKEKB is the upgrade plan of the current B-factory experiment with the KEKB accelerator at KEK. Its luminosity is designed to be 8x1035 /cm2/s (40 times higher than KEKB) and the integrated luminosity is expected to be 50 ab-1. In SuperKEKB, it is important to evaluate the beam induced BG and design the interaction region (IR) to assure the stable detector operation. To estimate the beam induced BG, we construct the beam-line simulation based on the GEANT4 simulation. In this paper, we report the BG evaluation and the IR design for SuperKEKB.
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.
GSI, Darmstadt
CERN, Geneva
The presence of an electron cloud in an accelerator generates a number of interesting phenomena. In addition to electron-driven beam instabilities, the electron "pinch" occurring during a beam-bunch passage gives rise to a highly nonlinear force experienced by individual beam particles. A simple 1-dimensional model for the effect of the electron pinch on the beam reveals a surprisingly rich dynamics. We present the model and discuss simulation results.
CERN, Geneva
The beam profile screens in the long SPS to LHC transfer lines were used to measure with high precision the emittance growth arising from scattering. The effective thickness of the scatterer could be varied by adding thick Al2O3 fluorescent screens, with the emittance measurement made using very thin Ti OTR screens. The technique allows the intrinsic variation in the emittance from the injector chain to be factored out of the measurement, and was applied to Pb82+ and protons, both with 450 GeV rigidity. The results are presented and the possible applications to the accurate benchmarking of nuclear interaction codes discussed.
UMAN, Manchester
Cockcroft Institute, Warrington, Cheshire
MERLIN is a highly abstracted particle tracking code written in C++ that provides many unique features, and is simple to extend and modify. We have investigated the addition of high order wakefields to this tracking code and their effects on bunches, particularly with regard to collimation systems for both hadron and lepton accelerators. Updates have also been made to increase the code base compatibility with current compilers, and speed enhancements have been made to the code via the addition of multi-threading to allow cluster operation on the grid. In addition, this allows for simulations with large numbers of particles to take place. Instructions for downloading the new code base are given.
TUB, Beijing
Tsinghua University, Beijing
HU/AdSM, Higashi-Hiroshima
LBNL, Berkeley, California
JAEA/TARRI, Gunma-ken
During the beam crystallization process, the main heating source is Intra-beam scattering (IBS), in which the Coulomb collisions among particles lead to a growth in the 6D phase space volume of the beam. The results of molecular dynamics (MD) simulation have shown an increase of heating rate as the temperature is increased from absolute zero, but then a peak in the heating rate, and subsequent decrease with ever increasing temperature*. This phenomenon has been carefully studied by Y. Yuri, H. Okamoto, and H. Sugimoto**. On the other hand, in the traditional IBS theory valid at high temperatures, heating rate is monotonically increasing as the temperature becomes lower***. In this paper we attempt to understand the "matching" at low temperatures between the MD results and traditional IBS theory, by including many body effects in the traditional IBS theory. In particular the Debye shielding is included. We shall present how the traditional theory is modified by shielding, and show how this effect improves the "matching" with the results from MD.
* J. Wei, H. Okamoto, and A. Sessler, Phys. Rev. Lett. 80, 2606
** Y.Yuri, H. Okamoto, and H. Sugimoto, J. Phys. Soc. Jpn. 78, 124501
***A. Piwinski, Lect. Notes Phys. 296, 297 (1988)
INFN/LNF, Frascati (Roma)
SLAC, Menlo Park, California
Some collective effects have been studied for the SuperB* high luminosity collider. Estimates of the effect of Intra Beam Scattering on the emittance and energy spread growths have been carried up for both the High Energy (HER, positrons) and the Low Energy (LER, electrons) rings. Electron cloud build up simulations for HER were performed with the ECLOUD code, developed at CERN**, to predict the cloud formation in the arcs, taking into account possible remediation techniques such as clearing electrodes. The new code CMAD, developed at SLAC***, has been used to study the effect of this electron cloud on the beam and assess the thresholds above which the electron cloud instability would set in.
* M. E. Biagini, proceedings of PAC'09.
** F. Zimmermann, CERN, LHC-Project-Report-95, 1997.
*** M. Pivi, proceedings of PAC'09.
UMAN, Manchester
The collimation system of the LHC will be critical to its success, as the halo of high energy (7 TeV) particles must be removed in such a way that they do not deposit energy in the superconducting magnets which would quench them, or showers in the experiments. We study the properties of the LHC collimation system as predicted by the Merlin and Sixtrack/K2 simulation packages, and compare their predictions for efficiency and halo production, and the pattern of beam losses. The sophisticated system includes many collimators, serving different purposes. Both programs include energy loss and multiple Coulomb scattering as well as losses through nuclear scattering. The MERLIN code also includes the effects of wakefields. We compare the results and draw conclusions on the performance that can be achieved.
Nagoya University, Nagoya
UVSOR, Okazaki
Sokendai - Okazaki, Okazaki, Aichi
We are developing an ultra-short gamma ray pulse source based on laser Compton scattering technology at the 750 MeV electron storage ring UVSOR-II. Ultra-short gamma ray pulses can be generated by injecting femtosecond laser pulses into the electron beam circulating in an electron storage ring from the direction perpendicular to the orbital plane. The energy, intensity, and pulse width of the gamma rays have been estimated to be 6.6 MeV, 2.4× 106 photons s-1, and 150 fs, respectively, for the case of UVSOR-II with a commercially available femtosecond laser. These parameters can be tuned by changing the incident angle of the laser to the electron beam, electron energy, and the size of the laser. A preliminary head-on collision experiment was carried out. The measured spectral shape agreed well with simulation including the detector response calculated by the EGS5 code*, which implied the generation of gamma rays by laser Compton scattering and the validity of the estimation of the gamma ray intensity in the case of 90-degree collisions.
* H. Hirayama et al., SLAC-R-730, (2005).
LLNL, Livermore, California
SLAC, Menlo Park, California
UCB, Berkeley, California
Recent progress in accelerator physics and laser technology have enabled the development of a new class of tunable gamma-ray light sources based on Compton scattering between a high-brightness, relativistic electron beam and a high intensity laser pulse produced via chirped-pulse amplification (CPA). A precision, tunable Mono-Energetic Gamma-ray (MEGa-ray) source driven by a compact, high-gradient X-band linac is currently under development and construction at LLNL. High-brightness, relativistic electron bunches produced by an X-band linac designed in collaboration with SLAC will interact with a Joule-class, 10 ps, diode-pumped CPA laser pulse to generate tunable γ-rays in the 0.5-2.5 MeV photon energy range via Compton scattering. This MEGa-ray source will be used to excite nuclear resonance fluorescence in various isotopes. Applications include homeland security, stockpile science and surveillance, nuclear fuel assay, and waste imaging and assay. The source design, key parameters, and current status are presented, along with important applications, including nuclear resonance fluorescence, photo-fission, and medical imaging.
YerPhI, Yerevan
We consider generation of diffusive radiation by a charged particle passing through a random stack of plates in the infrared region. Diffusive radiation originates due to multiple scattering of pseudophotons on the plates. To enhance the radiation intensity one needs to make the scattering more effective. For this goal we suggest to use materials with negative dielectric constant .
USTC/NSRL, Hefei, Anhui
Hefei Advanced Light Source(HALS) will be a high brightness light source with about 0.2nmrad emittance at 1.5GeV and about 400m circumference. To enhance brilliance, very low beam emittance is required. High brightness demand and relative low energy will make emittance a critical issue in ring design. Intra-beam scattering(IBS) is usually thought a fundamental limitation to achieve low emittance. Here we preliminarily estimate the emittance growth due to IBS for the temporary lattice design of HALS based on Piwinski and Bjorken-Mtingwa theories, and discuss the effect of implementation of damping wiggler and harmonic cavity to lower the emittance.
NSC/KIPT, Kharkov
In the paper the expression for cross section of Compton scattering derived with classical electrodynamics approach is presented. The comparative analysis of the Compton cross section value calculated with the presented expression and with expression derived with quantum approach was carried out for the case of head on collision and low photon beam intensity. Results of the analysis show the good agreement of both approaches. It proves legitimacy of classical electromagnetic approach use for analysis of particle beam dynamics and estimation of generated x-ray beam parameters in laser electron storage rings.
SLAC, Menlo Park, California
Over the past year, we have worked out a baseline design for PEP-X, as an ultra-low emittance storage ring that could reside in the existing 2.2-km PEP-II tunnel. The design features a hybrid lattice with double bend achromat cells in two arcs and theoretical minimum emittance cells in the remaining four arcs. Damping wigglers reduce the horizontal emittance to 86 pm-rad at zero current for a 4.5 GeV electron beam. At a design current of 1.5 A, the horizontal emittance increases, due to intra-beam scattering, to 164 pm-rad when the vertical emittance is maintained at a diffraction limited 8 pm-rad. The baseline design will produce photon beams achieving a brightness of 1022 (ph/s/mm2/mrad2/0.1% BW) at 10 keV in a 3.5-m conventional planar undulator. Our study shows that an optimized lattice has adequate dynamic aperture, while accommodating a conventional off-axis injection system. In this paper, we will present the study of the lattice properties, nonlinear dynamics, intra-beam scattering and Touschek lifetime, and collective instabilities. Finally, we discuss the possibility of partial lasing at soft X-ray wavelengths using a long undulator in a straight section.
ORNL, Oak Ridge, Tennessee
ORNL RAD, Oak Ridge, Tennessee
All stages of the SNS development require significant research and development work in the field of radiological shielding design to assure safety from a radiation-protection point of view for facility operation and to optimize accelerator and target performance. Here we present an overview of on-going shielding work and associated with it procedures and regulations. In the present time, the most of the shielding work is focused on the neutron beam lines and their instrument enclosures in order to commission and provide save operation in the future. This effort is performed according to the guidelines for shielding calculations of SNS neutron beam lines, which sets standards for the analyses and helps to prepare for the Instrument Readiness Review (IRR). The IRR ascertains that the instruments has been design, constructed, and installed to allow safe operation and maintenance. In addition, there is still support for the accelerator facility to redesign parts of the accelerator structures, to design shielding for removed components and test stands for accelerator structures, and for radiation protection analyses for evaluations of accelerator and target safety systems.
ODU, Norfolk, Virginia
Using high-pressure RF cavities for muon colliders would provide higher accelerating gradients, that is crucial for fast acceleration of short-living muons .This approach requires a good evaluation for mechanisms of muon - low-Z gas interaction, including such effects as multiple scattering and space charge effects. Most present simulation tools (GEANT4, G4MICE) for muon beams are based on single particle tracking, where collective effects are not taken into account. We use a modified molecular dynamic simulation technique to study effects of both multiple scattering and space charge screening by the gas on scattering, energy loss, and propagation of muons during both ionization cooling and acceleration.
NIRS, Chiba-shi
The development of the screen monitor system (SCN) at the Heavy Ion Medical Accelerator in Chiba (HIMAC) comprises the surveillance of the carbon beam. In the three-dimensional scanning system for the carbon therapy, the beam qualities, i.e., position, size and intensity of the beam, play a significant role for the patient's treatment. Therefore, we designed a semi-nondestructive monitoring system located on the the high-energy beam transport line to monitor the beam qualities by using a thin fluorescent screen and a high-speed charge-coupled device. The beam position and profile were obtained from the light emitting distribution of the screen. The SCN was checked on the prototype scanning system at HIMAC and succeeded to monitor the beam real-time in steps of about 10 msec, corresponding to a 100 Hz sampling rate. The developments steps will focus toward a operation at HIMAC's new therapy facility extension, recently. In the conference, we would like to report on details of the automatic beam tuning before starting the treatment and the interlock system during therapy using the SCN.
CERN, Geneva
The maximum tolerable pressure value in the chamber of the CLIC electron Main Linac is determined by the threshold above which the fast ion instability sets in over a bunch train. Instability calculations must take into account that, since the accelerated beam becomes transversely very small, its macroscopic electric field can reach values above the field ionization threshold. In this paper we first discuss threshold values of the electric field for field ionization and the extent of the transverse region that gets fully ionized along the ML. Then, we show the results of the instability simulations from the FASTION code using the new model, and consequently review the pressure requirement in the ML.
UCR, Riverside, California
Fermilab, Batavia
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
In the Muon Ionization Cooling Experiment (MICE), muons are cooled by ionization cooling. Muons are passed through material, reducing the total momentum of the beam. This results in a decrease in transverse emittance and a slight increase in longitudinal emittance, but overall reduction of 6D beam emittance. In emittance exchange, a dispersive beam is passed through wedge-shaped absorbers. Muons with higher energy pass through more material, resulting in a reduction in longitudinal and transverse emittance. Emittance exchange is a vital technology for a Muon Collider and may be of use for a Neutrino Factory. Two ways to demonstrate emittance exchange in the straight solenoidal lattice of MICE are discussed. One is to let a muon beam pass through a wedge shaped absorber; the input beam distribution must be carefully selected to accommodate chromatic aberrations in the solenoid lattice. Another approach is to use the input beam for MICE without beam selection. In this case no polynomial weighting is involved; however, a more sophisticated shape of the absorber is required to reduce longitudinal emittance.
National Technical University of Athens, Zografou
CERN, Geneva
Due to the high bunch density, the output emittances of the CLIC Damping Rings (DR) are strongly dominated by the effect of Intrabeam Scattering (IBS). In an attempt to optimize the ring design and using classical IBS formalisms and approximations, the scaling of the extracted emittances and IBS growth rates is being studied, with respect to several ring parameters including energy, bunch charge, optics and wiggler characteristics. Results from the simulations using a multi-particle tracking code are also presented.
CIEMAT, Madrid
CERN, Geneva
The goal of the present CLIC test facility (CTF3) is to demonstrate the technical feasibility of the CLIC scheme. The Test Beam Line (TBL) is used to study a CLIC decelerator focusing on 12 GHz power production and the stability of the decelerated beam. The extracted CTF3 drive beam from the combiner ring (CR) features a maximum intensity of 28 A and 140 ns pulse duration, where the Test Beam Line consists of 16 cells, each one including a BPM, a quadrupole on top of a micrometer-accuracy mover and a RF power extractor so-called PETS (Power Extraction and Transfer Structure). This paper describes the first prototype fabrication techniques, with particular attention to the production of the long copper rods which induce the RF generation. A special test bench for the characterization of the device with low RF power measurements has been developed. Performed mesurements of the scattering parameters and the electric field profile along the structure are carefully described. Finally, the prototype has been installed at CLEX, and first measurements with beam are also reported.
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
KEK, Ibaraki
The beam loss caused by the nuclear scattering together with the multiple Coulomb scattering at the stripping foil is one of the key issue in RCS (Rapid Cycling Synchrotron) of the J-PARC (Japan Proton Accelerator Research Accelerator). In order to have a very realistic understanding, a systematic study with both experiment and simulation has been carried out recently. A total of seven targets with different thickness were used and the measured beam losses were found to be good in agreement with that in the simulation. A detail and realistic understanding from such a study will be very useful not only to optimize the foil system including the thickness and size at present with the injection beam energy of 181 MeV but also for the near future upgrade with 400 MeV and in addition can be a good example for similar existing and proposing projects.
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
KEK/JAEA, Ibaraki-Ken
KEK, Ibaraki
The hybrid type thick boron-doped carbon (HBC) stripping foils are installed and used for the beam injection at the 3GeV RCS (Rapid Cycling Synchrotron) in J-PARC (Japan Proton Accelerator Research Complex). The HBC foils are developed by Sugai group in KEK, which improved the lifetime drastically. Up to now, the performance deterioration of the stripping foils can not be seen after the long beam irradiation for the 120kW user operation and 300kW high power beam demonstration at the RCS. In order to examine the characteristic of the HBC foils, various beam studies were carried out. The beam-irradiated spot at the foil was measured by scanning the foil setting position, the charge exchange efficiency was evaluated with various thickness foils, and the effect of the SiC fibers supporting the foil mounting was checked with different mounting foils. Beam study results obtained with using the HBC foils will be presented. In addition, the trends of outgas from the stripping foils and the deformations of the foils during the beam irradiation will be reported.
CERN, Geneva
Beam physics considerations for the stripping foil of the 160 MeV PSB H- injection system are described, including the arguments for the foil type, thickness, geometry and positioning. The foil performance considerations are described, including expected stripping efficiency, emittance growth, energy straggling, temperature and lifetime. The different beam loss mechanisms are quantified in the context of the aperture limits, operational considerations and collimation requirements.
TU Darmstadt, Darmstadt
TEMF, TU Darmstadt, Darmstadt
At the superconducting 130 MeV Darmstadt electron linac S-DALINAC* a source of polarized electrons** is being installed, extending the experimental capabilities with polarized electron and polarized photon probes for nuclear structure studies. This involves disassembling the existing low energy test stand and rebuilding the beam line in the accelerator hall. The beam itself is produced from a GaAs cathode by irradiation with a pulsed laser. The low-energy electron beam line includes diagnostic elements, a Wien filter for spin manipulation, a 100 keV Mott polarimeter for polarization measurement and a chopper-prebuncher section to modulate the time structure of the beam. At higher energies a 5-10 MeV Mott polarimeter and a 50-130 MeV Moeller polarimeter as well as a Compton transmission polarimeter will be installed to measure the beam polarization after acceleration. The Mott polarimeter is working with backscattered electrons under 165° scattering angle while for the Moeller polarimeter a wide-angle (3°-15°) spectrometer magnet was designed. We report on the performance of the test stand, the ongoing implementation, and the polarimeter research and development.
* A. Richter, Proc. EPAC 96, Sitges, p.110.
** Y. Poltoratska et al., AIP Conference Proc. 1149 (2009), p.983.
JAEA/TARRI, Gunma-ken
To achieve ultra-low-fluence large-area uniform irradiation of ion beams for advanced applications in the field of materials sciences and biotechnology, a uniform-beam irradiation system has been developed using multipole magnets at the Japan Atomic Energy Agency (JAEA) cyclotron facility. The system consists of a beam attenuator for the wide-range intensity control, an electrostatic beam chopper for the control of irradiation time, scattering foils for conditioning of the initial beam distribution, octupole magnets for transverse tail-folding, sextupole magnets for the correction of the beam misalignment, and the diagnostic station of the two-dimensional beam profile. In this paper, recent experimental results are described, especially on the formation of a beam with a uniform transverse distribution by the combination of the sextupole and octupole magnets.
PSI, Villigen
A simulation based optimization of a collimator system at the 590 MeV PSI proton accelerator is presented, for the ongoing beam power upgrade from the current 1.2 MW [2 mA] towards 1.8 MW [3 mA]. The collimators are located downstream of the 4 cm thick graphite meson production target. These are designed to shape the optimal beam profile for low-loss beam transport to the neutron spallation source SINQ. The optimized collimators are predicted to withstand the beam intensity up to 3 mA, without sacrificing intended functionalities. The collimator system is under the heavy thermal load generated by a proton beam power deposition approximately of 240 kW at 3 mA, and it needs an active water cooling system. Advanced multiphysics simulations are performed for a set of geometric and material parameters, for the thermomechanical optimization of the collimator system. In particular, a FORTRAN subroutine is integrated into CFD-ACE+, for calculating local beam stopping power in the collimator system. Selected results are then compared with those of full MCNPX simulations.
CERN, Geneva
Royal Holloway, University of London, Surrey
We report on a study of muon backgrounds in CLIC. For this we combined halo and tail generation using HTGEN with detailed tracking by BDSIM of impacting halo particles and resulting secondaries from the collimation spoilers to the detector.
INFN-Ferrara, Ferrara
IHEP Protvino, Protvino, Moscow Region
UNIFE, Ferrara
Università dell'Insubria & INFN Milano Bicocca, Como
INFN/LNL, Legnaro (PD)
PNPI, Gatchina, Leningrad District
JINR, Dubna, Moscow Region
INFN MIB, MILANO
CERN, Geneva
Enrico Fermi Institute, University of Chicago, Chicago, Illinois
INFN-Trieste, Trieste
INFM-CNR, Istituto Nazionale di Fisica della Materia - Consiglio Nazionale delle Ricerche, Brescia
New results in coherent interaction of negatively-charged particles with bent crystals showed unprecedentedly and significantly high efficiency to manipulate such beams, in the same way as for positively charged particles. Key feature under experimental attainment was the usage of high-quality suitably thin silicon crystals. We experimentally tested crystals Vs. 150 GeV negative pions at external lines of CERN SPS. We observed planar channeling at full deflection angle 30% high single-pass efficiency and large acceptance (about 20μrad). Moreover in the axial case, we reached more than 90% deflection efficiency and larger acceptance (about 60μrad). We also observed volume reflection in a bent crystal, at more than 70% single-pass efficiency with such a wide acceptance as the bending angle. At last, volume reflection by several planes in a single bent crystal was successfully tested with very high efficiency (about 80%). In summary both channeling and volume reflection modes appear to be useful technique for the manipulation of negatively charged beams, e.g. for collimation in the new generation of high intensity accelerators.
The UA9 collaboration
GPI, Hamamatsu
Hamamatsu Photonics K.K., Hamamatsu
IHI, Yokohama
A technique for remote detection of hidden objects is an urgent issue, but is not yet realized, because a source and a sensor must be located on the same side of the object. An ultra-intense laser can produce extremely short and directional radiations, that is the inverse Compton scatterings used for the backscattering system. We here demonstrate that the laser-wakefiled-accelerated 10-MeV electrons inversely scatter the same laser light to keV X-ray emissions. A 10 TW OPCPA Ti:sapphire laser BEAT ( 1J output, wavelength 815 nm, and pulse width 150fs) is divided to two beams. A 0. 8-J beam is focused to an entrance edge of helium gasjet to accelerate electrons via wakefield and the other 0.2-J beam is focused to the exit of the plasma channel from the opposite direction. A second harmonic probe light measured the channel density. To the upstream direction of the latter beam, a CdTe detector analyzed the Compton spectrum under a photon counting mode* in the range of 1 keV to 20 keV, which well agrees with that calculated from the obtained electron spectrum up to a few tens MeV. We also have observed that the emission is strong into the laser axis direction.
*H. Kuwabara, Y. Mori, Y. Kitagawa, 'Coincident Measurement of a Weakly Backscattered X-ray with a CPA Laser-Produced X-ray Pulse', Plasma Fusion Research: 3, 003-004 (2008).
Euclid TechLabs, LLC, Solon, Ohio
ANL, Argonne
Current advanced accelerator modeling applications require a more sophisticated treatment of dielectric and paramagnetic media properties than simply assuming a constant permittivity or permeability. So far active media have been described by a linear, frequency-dependent, single-frequency, scalar dielectric function. We have been developing algorithms to model the high frequency response of dispersive, active, and nonlinear media. The work described also has applications for modeling of other electromagnetic problems involving realistic dielectric and magnetic media. Results to be reported include treatment of multiple Lorentz resonances based on auxiliary differential equation, Fourier, and hybrid approaches. We will also report on recent measurements of paramagnetic active microwave materials using EPR spectroscopy. Comparison of the results to numerical simulations will be presented.