PSI, Villigen
The Swiss FEL linac consists of a 450 MeV S-band injector and of a main linac at the C-band frequency (5.712 GHz) aiming at a final energy of 5.8 GeV. The main linac is composed of 26 RF modules. Each module consists of a single 50 MW klystron and its solid-state modulator feeding a pulse compressor and four accelerating structures. The two-meter long C-band accelerating structures have 110 cells, including the two coupler cells, and operate with a 2π/3 phase advance. We report here on RF studies performed on the accelerating structures with different cell topologies and on the pulse compressor where a Barrel-Open Cavity (BOC) design is adopted. The power requirements for the different accelerating structures with the single and two-bunch operation are also presented.
ELETTRA, Basovizza
FERMI@Elettra is a single-pass FEL user-facility covering the wavelength range from 100 nm (12 eV) to 4 nm (310 eV) and is located next to the third-generation synchrotron radiation facility Elettra in Trieste, Italy. The first electron beam from the photocathode electron rf gun and injector system was extracted in August 2009. Commissioning and installation of the remaining linac and linac systems are continuing and will alternate through this year . The linac is based on normal conducting S-band technology. It uses fifteen 3 GHz 45 MW peak RF power plants powering the gun, the accelerating structures, and the RF deflectors, and when completed will be able to deliver greater than 1.5 GeV electron beams to the FEL undulator system. This paper provides a summary of the installation activities and discusses the performances results of the main subassemblies both during the initial checkouts and through the commissioning of the accelerator.
KEK, Ibaraki
JAEA/ERL, Ibaraki
ISSP/SRL, Chiba
Future light sources based on the Energy Recovery Linac (ERL) are expected to bring innovation to the synchrotron radiation (SR) science. Our Japanese collaboration team plans to construct a 5-GeV ERL which can produce super-brilliant and ultra-short pulses of SR as well as can be a driver for a proposed X-ray free-electron laser oscillator (X-FELO). In order to establish the key technologies for the ERL, we are conducting aggressive R&D efforts. Concerning our high-brightness photocathode DC electron gun, we succeeded to apply a DC high voltage of 500 kV through a support rod. Both cryomodules for the injector and the main-linac are also under development. In order to demonstrate reliable operations of such key technologies, we plan to construct the Compact ERL (cERL) at KEK. During FY2009, we prepared the infrastructure for the cERL which includes renovation of the building (the East Counter Hall), renovation of cooling-water system and electrical substation, installation of liquid helium refrigerator, and installation of a part of the rf source. In this paper, we present up-to-date status of the ERL and the Compact ERL projects in Japan.
KEK, Ibaraki
Development of the superconducting injector Linac for compact ERL has been continuing at KEK. The cryomodule including three two-cell SC cavities was designed. Two prot-type two-cell cavities were fabricated, and the vertival test were carried out after the standard surface preparation at STF. The high power tests of the input couplers were also carried out at the test stand with 300 kW cw klystron. The status of the cERL injector cryomodue will be reported.
KEK, Ibaraki
JAEA/ERL, Ibaraki
ISSP/SRL, Chiba
A construction of the Compact ERL is planned in KEK, Japan. A demonstration of the performance of the main linac super-conducting accelerating system is one motivation of the project. We have been designing a cryo-module, which works under CW operation, and contains two 9-cell cavities, with input couplers, frequency tuners and HOM dampers. Most of these components have been specially developed for ERL operation. Two proto-type of the 9-cell cavity were constructed. First one was vertically tested and suffered from field emissions. Second one is now waiting a measurement. High power component tests have been carried out for input coupler. At first, large temperature rise was observed at a ceramic window part due to unexpected dipole resonance. After that, new version of window was designed and successfully passed 20kW CW power with reflection. Proto-types of HOM damper were also constructed. Cooling tests have been performed for them to verify cooling ability against more than 100W heat load, under vacuum condition. A cryo-module will be completed in 2012, and cooling tests and beam tests will follow.
HZB, Berlin
Energy recovery linacs (ERLs) are proving to be a powerful option to provide very high current beams with exceptional beam parameters and the flexibility to tailor these for many applications, from next-generation light sources to electron coolers. Helmholtz Zentrum Berlin (HZB) is focusing on ERLs for future x-ray light sources. Although ERL facilities exist for the IR and THz range, their moderate parameters (current, emittance, energy) are insufficient for future x-ray sources. HZB is therefore proposing to develop the 100-MeV ERL facility BERLinPro for accelerator studies and technology development to demonstrate the feasibility of an x-ray user facility. This paper presents an overview of the project and the key components of the facility.
PSI, Villigen
The Paul Scherrer Institute is commissioning a 250 MeV injector test facility in preparation for the SwissFEL project. Its primary purpose is the demonstration of a high-brightness electron beam meeting the specifications of the SwissFEL main linac. At the same time it is advancing the development and validation of the accelerator components needed for the realization of the SwissFEL facility. We report the results of the first commissioning phase, which includes the gun section of the injector up to 7 MeV electron energy. Electrons are generated by a 2.6-cell laser-driven photocathode RF gun operating at 3 GHz followed by an emittance compensating focusing solenoid. The diagnostic system for this phase consists of a spectrometer dipole, a series of screens and beam position monitors and several charge measuring devices. Slit and pinhole masks can be inserted for phasespace scans and emittance measurements. The completion of the entire injector facility proceeds in three stages, culminating with the integration of the magnetic compression chicane expected for early 2011.
DESY, Hamburg
JLAB, Newport News, Virginia
The Andrzej Soltan Institute for Nuclear Studies, Centre Swierk, Swierk/Otwock
The European XFEL will use superconducting TESLA cavities operating with 650 μs long bunch trains. With 220 ns bunch spacing and 10 Hz RF-pulse repetition rate up to 27000 high quality bunches/s will be delivered to insertion devices generating unprecedented high average brilliance photon beams at very short wavelength. While many experiments can take advantage of full bunch trains, others prefer an increased several μ-seconds intra pulse distance between bunches, or short bursts with kHz repetition rate. With the nominal RF-pulse structure these features will lead to a substantially reduced number of bunches per second and therefore to significantly lower average brilliance. We discuss here an R&D program aiming for a far future upgrade of the European XFEL; operation in the cw and/or near-cw mode. The program profits from the continuous improvement in performance of TESLA cavities, which allows for longer RF-pulses in comparison with the current design. We present test results of a SRF electron injector and a new RF-power source, and some modification of the HOM damping scheme, which will avoid the necessity of re-assembly of the XFEL accelerator for the upgraded operations.
RAS/INR, Moscow
MEPhI, Moscow
Nano, Moscow
DESY Zeuthen, Zeuthen
DESY, Hamburg
Transverse Deflecting Systems are designated for longitudinal beam diagnostics of ultra-short electron bunches in modern FEL projects. At the European XFEL, Transverse Deflecting Systems are foreseen at three locations. A prototype of the TDS in the injector of the European XFEL will be installed at PITZ which is identical in terms of deflecting structure, low-level RF system and powerful RF hardware. This PITZ TDS has the aim to prove the required performance for all TDS subsystems as well as serve as a diagnostics tool for PITZ. Results of the test cells measurements of a S-band travelling wave structure are presented, showing very good agreement with calculated parameters. RF power supply system, including 3 MW klystron and other RF hardware, is described. Solid state 130 kV Marx modulator has been developed for the klystron feeding. 10 kV module of the modulator has been built and tested. The modulator allows for high voltage shutdown within pulse.
Uni HH, Hamburg
DESY, Hamburg
PSI, Villigen
DELTA, Dortmund
The free-electron laser facility FLASH at DESY (Hamburg) was upgraded during a five-month shutdown in winter 2009. Part of this upgrade was the installation of a direct seeding experiment in the XUV spectral range. Beside all components for transport and diagnostics of the photon beam in and out of the accelerator environment, a new 10 m long variable-gap undulator was installed upstream of the existing FLASH undulator system. The seed pulses are generated within a noble-gas jet by focusing 40 fs long Ti:Sa laser pulses into it resulting a comb of higher harmonics. In the first phase of the experiment the 21st harmonic of the 800 nm drive laser will be used to seed the FEL process. The commissioning of the experiment has started in April and the first results are expected after the FLASH commissioning period mid of summer 2010. The experimental setup and the commissioning procedures as well as first result will be presented.
Fermilab, Batavia
DESY, Hamburg
A Third Hamonic/3.9 GHz superconducting RF module was recently installed in the FLASH facility at DESY. Ultra short bunches with high peak current are required to efficiently create high brilliance coherent light and these can be produced by means of a 2-stage transverse magnetic chicane bunch compression scheme coupled with off-crest acceleration. The long bunch tails and reduced peak current which result from the nonlinearities of the RF since wave can be eliminated by the addition of a 3rd harmonic RF system. Such a system can also allow for the creation of uniform intensity bunches of adjustable length necessary for seeded operation. We present here a summary of commissioning and early operating experience of the newly-installed device.
JASRI/SPring-8, Hyogo-ken
RIKEN/SPring-8, Hyogo
The injector of the 8 GeV linac generates an electron beam of 1 nC, accelerates it up to 30 MeV, and compresses its bunch length down to 20 ps. Even slight RF instability in its multi-stage bunching section fluctuates the bunch width and the peak current of an electron beam and it accordingly results in unstable laser oscillation in the undulator section. The acceptable instabilities of the RF fields in the cavities, which permit 10% rms variation of the peak beam current, are only about 0.01% rms in amplitude and 120 fs rms in phase according to beam simulation. The long-term RF variations can be compensated by feedback control of the RF amplitude and phase, the short-term or pulse-to-pulse variations, however, have to be reduced as much as possible by improving RF equipment such as amplifiers. Thus we have carefully designed and manufactured the RF cavities, amplifiers and control systems, giving the highest priority to the stabilization of the short-term variations. Components of the injector will be completed by the end of the May 2010, and the injector will be perfected in the summer 2010. We will present the performance of the completed devices in the conference.
SLAC, Menlo Park, California
With the growing demand for FEL light sources, cost issues are being revaluated. To make the machines more compact, higher-frequency room-temperature linacs are being considered, in particular, ones using C-band (5.7 GHz) rf technology where 40 MV/m gradients are possible. In this paper, we show that an X-band (11.4 GHz) linac using the technology developed for NLC/GLC can provide an even lower cost solution. In particular, stable operation is possible at gradients of 100 MV/m for single bunch operation, and 70 MV/m for multibunch operation. The concern of course is whether the stronger wakefields will lead to unacceptable emittance dilution. However, we show that the small emittances produced in a 250 MeV, low bunch charge, LCLS-like S-band injector and bunch compressor can be preserved in a multi-GeV X-band linac with reasonable alignment tolerances.
ELETTRA, Basovizza
FERMI@Elettra is a soft X-ray, fourth generation light source facility in the last phase of its construction stage at the Elettra Laboratory in Trieste, Italy. It will be based on a seeded FEL, driven by the existing normal conducting linac that is presently expected to operate at 1.5 GeV. Two differet FEL lines will produce very short coherent photon pulses (25-200 fs) in the UV snd soft X-ray region (100-4 nm). FEL1 will cover 100-20 nm, FEL2 20-4 nm. Here a possibility to extend the FERMI spectral range capability down to the water window (1.0-2.0 nm) is presented. The suggested upgrading foresees the increase of the linac energy up to 2.4-2.5 GeV, leaving untouched the existing undulator chains and the overall length of the accelerator.
RAS/INR, Moscow
The hybrid HE11 mode in the cylindrical disk loaded deflectors is twice degenerated. To ensure operational performance and stabilize the position for the plane of deflection, the dispersion curve for modes with perpendicular field polarization must be shifted in frequency with respect to the curve for modes with operating polarization. A lot of decisions, based on the deterioration of the axial symmetry of the structure, are known for this purpose. The resonant method of stabilization is proposed. Resonant elements ' slots, coupled only with modes of perpendicular polarization, are placed in the disks. Two created branches of dispersion curve for composed slot - structure modes are generated and placed symmetrically with respect to the non perturbed dispersion curve for operating modes. In the plane stabilization it provides qualitative advantage with respect a simple frequency shift, because cancels, in the first order, the influence of modes with perpendicular field polarization on the plane of deflection. The criteria for the slots definition are presented. The example of application for the traveling wave S-band deflector is described as well.
LANL, Los Alamos, New Mexico
NPS, Monterey, California
Modern electron injectors consist of an RF structure with a photocathode integrated into the first full-wave half-cell or quarter-wave full-cell. While the cathode gradients in pulsed, normal-conducting RF injectors exceed 100 MV/m, which lead to substantial dark currents, those of cw normal-conducting and superconducting RF injectors are typically 10-20 MV/m. Emittance compensation has been modeled for both NCRF and SRF injectors to generate nC electron bunches with normalized rms emittance of ~2 mm-mrad. The use of solenoid and RF focusing in combination with relatively low cathode gradients can mitigate the space-charge-induced radial expansion in nC bunches, resulting in low emittance and also low dark currents.
[1] D.C. Nguyen et al. "Overview of the 100mA average-current RF photoinjector" NIMA 528, 71
[2] A. Arnold et al. "Development of a superconducting RF photoelectron injector" NIMA 577, 440
IHEP Beijing, Beijing
CIAE, Beijing
In the next two decades, China will be in period of fast development of nuclear power to meet the energy demands of the rapid economy growth and to cut down the CO2 release. Accelerator Driven System is recognized as the best option for nuclear radioactive waste transmutation. ADS long-term development roadmap has been proposed. Based on the ADS basic study in the last decade, a samll-scale ADS facility is going to be built to do experimental research on ADS system. In this paper, we will first review the previous R&D activity on ADS linac research in China, and then introduce the design of the linac in the small-scale ADS facility.
IPN, Orsay
IAP, Frankfurt am Main
IN2P3, Paris
INFN/LASA, Segrate (MI)
SCK-CEN, Mol
The goal of the MYRRHA project is to demonstrate the technical feasibility of transmutation in an Accelerator Driven System (ADS) by building a new flexible irradiation complex in Mol (Belgium). The MYRRHA facility requires a 600 MeV accelerator delivering a maximum proton flux of 4 mA CW operation. Such a machine belongs to the category of the high-power proton accelerators, with an additional requirement for exceptional reliability: because of the induced thermal stress to the subcritical core, the number of unwanted beam interruptions should be minimized down to the level of about 10 per 3-month operation cycle, a specification that is far above usual proton accelerators performance. This paper describes the reference solution adopted for such a machine, based on a so-called 'fault-tolerant' linear superconducting accelerator, and presents the status of the associated R&D.
KAERI, Daejon
A 100MeV proton accelerator is developed by the Proton Engineering Frontier Project (PEFP). As a front part, a 20MeV linac has been installed and operated at Korea Atomic Energy Research Institute (KAERI) site. Among the components for the 100MeV accelerator, some parts were installed and tested by using 20MeV linac. One modulator for a 100MeV linac was installed to drive two klystrons simultaneously which were used for a 20MeV linac. Various operating parameters such as a long term voltage fluctuation and control performance are checked during operation. Also a LLRF system for 100MeV linac which was modified from the 20MeV system was installed and tested. In this paper, the operation characteristics of the 20MeV linac are presented especially from the viewpoint of the newly installed components such as a modulator and LLRF system.
TUB, Beijing
This paper will be generally reported that a new project of the Compact Pulsed Hadron Source (CPHS) led by the Department of Engineering Physics of Tsinghua University in Beijing, China. CPHS consists of a proton linac (13MeV, 16kW, Operating frequency 325MHz, peak current 50 mA, 0.5 ms pulse width at 50 Hz), a neutron target station (a Be target, moderators and reflector), and a small-angle neutron scattering instrument, a neutron imaging/radiology station, and a proton irradiation station. The linac accelerator is the main part of this project, which including a ECR ion source. LEBT section, a RFQ accelerator, a DTL linac and a HEBT An An experimental platform for further proton applications and more neutron beam lines will be added at a later stage. Currently, fabrication of the accelerator components has begun while the neutron target station, beam lines and instruments are under design study. The initial phase of the CPHS construction is scheduled to complete in the end of 2012.
IAP, Frankfurt am Main
Recent international cw operated high-current applications with ambitious requirements regarding beam power and quality ask for new linear accelerator developments. In this context the CH-structure (Crossbar-H-mode) has been developed at the Institute for Applied Physics (IAP) of Frankfurt University. It is a multi-cell drift tube cavity for the low and medium energy range operated in the H21-mode and can be used for superconducting as well as for room temperature applications. Because of the large energy gain per cavity, which leads to high real estate gradients, the CH-cavity is an excellent candidate for the efficient acceleration in high power proton and ion accelerators with fixed velocity profiles. One possible application for this kind of cavity is the EUROpean research programme for the TRANSmutation (EUROTRANS) of high level nuclear waste in an accelerator driven system (ADS), which requires an efficient high-current cw-linac (600 MeV, 4 mA, protons, 352 MHz). The paper describes the status of the CH-cavity development and the actual beam dynamics results for the reference design of the 17 MeV EUROTRANS injector.
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
Beam commissioning of the J-PARC linac started in November 2006 and 181 MeV acceleration was successfully achieved in January 2007. The linac had delivered beams for commissioning of accelerators and experimental facilities. Trip rates of the RFQ, however, unexpectedly increased in Autumn 2008, and that was the primary limitations of the operation days and power ramp up. We tried to recover by improvement of vacuum properties, tender conditioning and so on. By taking these measures, we can lengthen the continuous operation days and stand user operations. We ramped up the beam power from 20 kW to 120 kW for 3 GeV beam users in November 2009. This corresponds to the linac beam power of 7.2 kW and the linac has delivered beams at this power since then without significant troubles. And also we successfully demonstrated 300 kW at 3 GeV for 1 hour in December. We present the performance and operation experiences of the J-PARC linac.
LANL, Los Alamos, New Mexico
The Los Alamos Neutron Science Center (LANSCE) accelerator and beam delivery complex generates the proton beams that serve three neutron production sources, a proton radiography facility and a medical and research isotope production facility. The recent operating history of the facility, including both achievements and challenges, will be reviewed. Plans for performance improvement will be discussed, together with the underlying drivers for the ongoing LANSCE Life Extension project. The details of this latter project will also be discussed.
BNL, Upton, Long Island, New York
BNL 200 MeV linac has been under operation since 1970 and gone through several changes during its 40 year lifetime. The latest reconfiguration in low and medium energy (35 and 750 keV) beam transport lines results in about a factor of 2 reduction in the transverse emittance for the accelerated polarized proton beam, and for the unpolarized high current H- beam a several fold reduction in the radiation levels due to beam losses throughout the linac and isotope production facility complex with more beam current on the isotope production target. These improvements are achieved by proper matching into the linac in longitudinal as well as transverse phase space. This paper will emphasize how longitudinal matching resulted in lower emittance and beam losses.
BNL, Upton, Long Island, New York
RLNR, Tokyo
It is commonly preferred to have a short distance between an RFQ and a consequent DTL, however many devices has to be accommodated within a limited space. Our new medium energy beam transport line for proton beam is categorized as one of the severest cases. High field gradient quadrupoles (65 Tm) and newly designed steering magnets (6.5 mm in length) were fabricated considering the cross-talk effects. Also a new half wave length 200 MHz buncher is being studied. In the conference, the electro-magnetic field designs and the measured result will be discussed.
Imperial College of Science and Technology, Department of Physics, London
University of Warwick, Coventry
STFC/RAL/ISIS, Chilton, Didcot, Oxon
STFC/RAL/ASTeC, Chilton, Didcot, Oxon
In order to contribute to the development of high power proton accelerators in the MW range, to prepare the way for an ISIS upgrade and to contribute to the UK design effort on neutrino factories, a front end test stand (FETS) is being constructed at the Rutherford Appleton Laboratory (RAL) in the UK. The aim of the FETS is to demonstrate the production of a 60 mA, 2 ms, 50 pps chopped beam at 3 MeV with sufficient beam quality. The status of the FETS will be given and experimental results from the commissioning of LEBT and ion source will be presented. Previous measurements showed that the emittance of the beam delivered by the ion source exceeded our expectations by more than a factor of 3. Since then various changes in the beam extraction/post accelerator region reduced the beam emittance more than a factor of 2. The results from measurements will be compared with numerical simulations of the particle dynamics from the ion source to the end of the MEBT and the results discussed in respect to further work.
Fermilab, Batavia
We have been collecting data on the conditioning of the high-gradient accelerating cavities in the Fermilab 400 MeV H-Minus Linac for over 16 years [1]. This linac was upgraded in 1989 from a 201 MHz Alverez structure to include 805 MHz side-coupled cavities. Automated measurements of the sparking rate have been recorded since 1994 and are reported here. The sparking rate has declined since the beginning, but there are indications that this rate may have leveled off now. The X-rays emitted by the cavities are continuing to decrease.
[1] Kroc, et al., Proceedings of LINAC96, pp 338-340
Naples University Federico II and INFN, Napoli
NRT, Aprilia
INFN/LNS, Catania
Universita' degli Studi di Milano & INFN, Segrate
INFN/LASA, Segrate (MI)
ADAM, Geneva
INFN-Napoli, Napoli
Bari University, Science Faculty, Bari
INFN-Bari, Bari
ACLIP is a 3 GHz proton SCL linac designed as a booster for a 30 MeV commercial cyclotron. The whole accelerator is a 5 module structure coupled together. The final energy is 62 MeV well suitable for the therapy of ocular tumors. In order to treat deep-seated tumors the energy can be raised up to 230 MeV by adding a second linac. The possibility of using magnetrons, as the source of RF power, to reduce the overall cost of the machine, and the tile design (covered by a patent), named Back-to-Back Accelerating Cavity (BBAC), to efficiently accelerate protons starting from a low energy are two of the more relevant features of this project. The first module (from 30 to 35 MeV) has been full power RF tested in December 2008, showing that the design accelerating field could be easily reached. Then this module, along with all elements of the RF power setup, has been transferred to INFN-LNS in Catania at the end of April 2010 to carry out beam acceleration tests using a 30 MeV proton beam from the Superconducting Cyclotron. In this paper we will review the main features of the linac and discuss the results of the acceleration measurements carried out on this prototype.
BNL, Upton, Long Island, New York
IAP, Frankfurt am Main
Kyushu University, Hakozaki
The EBIS based preinjector for RHIC is now being commissioned. The Linac was delivered in April 2010 and commissioning started in May, 2010. It accelerates ions from 0.3 MeV/u to 2 MeV/u with 27 accelerating gaps, one internal quadrupole triplet, and operates at 100.625 MHz. The Linac is followed by a beam transport line to Booster which includes seven quadrupoles, two bunchers, and an achromatic bend system with resolution of 500 at 2 MeV/u to select the required charge state. Diagnostics include a pepperpot emittance probe, phase probes , fast Faraday cup, adjustable slits, three sets of multiwire profile monitors, three current transformers, two Faraday cups, and two beam stops. This contribution will report results of linac tuning and cold measurements, and commissioning of the Linac and high energy transport line with helium and gold beams.
BNL, Upton, Long Island, New York
Kyushu University, Hakozaki
IAP, Frankfurt am Main
Department of Energy Sciences, Tokyo Institute of Technology, Yokohama
The EBIS based preinjector for the RHIC is now being commissioned. During the step-wise commissioning of the preinjector from January 2009 to June 2010, the RFQ was commissioned first using Test EBIS in January 2009 and then moved to its final location and commissioned again with RHIC EBIS in March 2010. The RFQ accelerates ions from 17 keV/u to 300 keV/u and operates at 100.625 MHz. The RFQ is followed by a short (81 cm) Medium Energy Beam Transport (MEBT), which consists of four quadrupoles and one buncher cavity. Temporary diagnostics for this commissioning included an emittance probe, TOF system, fast Faraday cup, and beam current measurement units. This contribution will report results of RFQ and MEBT commissioning with helium and gold beams.
RLNR, Tokyo
A new type Linac, HSC (hybrid single cavity) linac for cancer therapy, which configuration combines RFQ (Radio Frequency Quadrupole) accelerating structure and DT (Drift Tube) accelerating structure is being finished designs and simulations now. This HSC linac design had adopted advanced power-efficiency-conformation, IH (Interdigital H) structure, which acceleration efficiency is extremely high in the low-middle energy region, and had also adopted most advanced computer simulation technology to evaluate cavity electromagnetic distribution. The study purposes of this HSC linac focus to design of injector linac for synchrotron of cancer radiotherapy facilities. Here, this HSC linac has an amazing space effect because of compact size by coupled complex acceleration electrode and integrated the peripheral device which is made operation easy to handle. The size of the HSC linac is very compact and is also easy to be adopted for cancer therapy in normal hospital.
TUB, Beijing
The Compact Pulsed Hadron Source (CPHS) system has been proposed and designed by the Department of Engineering Physics of Tsinghua University in Beijing, China. It consists of an accelerator front-end'a high-intensity ion source, a 3 MeV radiofrequency quadrupole linac (RFQ), and a 13 MeV drift-tube linac (DTL), a neutron target station, and some experimental stations. In our design, both RFQ and DTL share a single klystron which is capable of 2.5 MW peak RF power and a 3.33% duty factor. The 325 MHz klystron contains a modulating anode and has a 100 kW average output power. Portions of the RF system, such as pulsed high voltage power source, modulator, crowbar protection and RF transmission system are all presented in details in this paper.
IMP, Lanzhou
PKU/IHIP, Beijing
Heavy Ion Research Facility at Lanzhou (HIRFL) consists of two cyclotrons (SFC and SSC), one synchrotron (CSRm), and one storage ring (CSRe). The two cyclotrons are in series as the injector of the synchrotron. An additional LINAC injector for SSC is considered to increase the beam time at targets. The new injector consists of an RFQ and four IH-DTL tanks. A pre-buncher in the front of RFQ is 13 MHz to match the RF frequency of SSC. The LINAC can operate in two modes. In the first mode, the middle-mass ions output with energy of 0.54 MeV/u, and then SSC accelerates them up to the energy of 5.62 MeV/u. The beam is used to do the Super Heavy Elements (SHE) experiments. In the second mode, the very heavy ions output with energy of 0.97 MeV/u, and then SSC accelerates them up to energy of 10.06 MeV/u. The beam is injected into CSRm after stripped. Code LINREV and DAKOTA are used to design and optimize the acceleration structures of DTLs. The energy spread less than ±0.5% and bunch length less than 2.6 ns are achieved at the exit of the last tank. These can match the ideal acceptance of SSC. A simulation from LEBT to exit of DTL is done by Beampath to benchmark the design.
* All authors belong to PKU-IMP RF LINAC Research Center for Heavy Ions.
LANL, Los Alamos, New Mexico
LANSCE has been the centerpiece of large-scale science at Los Alamos National Laboratory for many decades. Recently, funding has been obtained to ensure continued reliable operation of the LANSCE linac and to allow planning to enable the first in a new generation of scientific facilities for the materials community. The emphasis of this new facility is "Matter-Radiation Interactions in Extremes" (MaRIE) which will be used to discover and design the advanced materials needed to meet 21st century national security and energy security challenges. MaRIE will provide the tools scientists need to develop next-generation materials that will perform predictably and on-demand for currently unattainable lifetimes in extreme environments. The MaRIE facility is based on a high-power upgrade to the existing LANSCE proton linac, a new electron linac and associated X-ray FEL to provide additional probe beams, and new experimental areas. A conceptual description of this new facility and its requirements will be presented.
IAP, Frankfurt am Main
Abstract A short RFQ prototype was built for tests of high power RFQ structures. We will study thermal effects and determine critical points of the design. HF-Simulations with CST Microwave Studio and measurements were done. The RF-Tests with continues power of 20 kW/m were finished successfully. Simulations of thermal effects with ALGOR are on focus now. First results and the status of the project will be presented.
IAP, Frankfurt am Main
NTG, Gelnhausen
The IH-type RFQ for the MAFF project at the LMU in Munich was operated at a beam test stand at the IAP in Frankfurt. It is the second IH-RFQ after the HIS at GSI and it has been designed to accelerate rare isotope beams (RIBs) with mass to charge ratios A/q up to 6.3 from 3 keV/u to 300 keV/u at an operating frequency of 101.28 MHz with an electrode voltage of 60 kV. Experimental results such as shunt impedance, energy spectrum and transmission will be presented.
IAP, Frankfurt am Main
GSI, Darmstadt
A new CW-RFQ has been built for the upgrade of the HLI (High Charge State Injector) of GSI for operating with a 28GHz-ECR-Ion source and simultaneous increase of the beam duty cycle from 25 % now to 100 %. The new HLI 4-rod RFQ will accelerate charged ions from 4 keV/u to 300 keV/u for the injection into the IH-structure. High beam transmission, a small energy spread and small transverse emittance growth and good input matching are design goals. Properties of this CW-RFQ, status of project and first measurements will be presented.
CERN, Geneva
CEA, Gif-sur-Yvette
The construction of Linac4, the new 160 MeV CERN H- injector, has started with the goal of improving the LHC injection chain from 2015 with a new higher energy linac. The low energy front end of Linac4 is based on a 352 MHz, 3-m long Radiofrequency Quadrupole (RFQ) accelerator. The RFQ accelerates the 70 mA, 45 keV H- beam from the RF source to the energy of 3 MeV. The fabrication of the RFQ has started at CERN in 2009 and is presently in progress, aiming at the completion of the full structure by early 2011. The RFQ consists of three modules, one meter each; the fabrication alternates machining phases and stress relief cycles, for copper stabilization. Two brazing steps are required: one to assemble the four parts composing a module and a second one to install the stainless steel flanges. In order to monitor that the tight mechanical and alignment budget is not exceeded, metrology measurements at the CERN workshop and RF bead-pull measurements are performed during the fabrication process. In this paper we report results obtained during the machining and the assembly of the first two modules of the Linac4 RFQ and data produced by RF measurements performed during their fabrication.
IMP, Lanzhou
IAP, Frankfurt am Main
BNL, Upton, Long Island, New York
A compact RFQ for carbon ion beam from a Laser-ion souce is being tested in IMP, Lanzhou. It is the first example of LINAC structures for IMP. Testing schemes and first results are presented.
IMP, Lanzhou
IAP, Frankfurt am Main
BNL, Upton, Long Island, New York
A RFQ has been designed and built for research of direct plasma injection scheme (DPIS), which can provide high current and highly charged beams. Because of the strong space charge forces of beam from laser ion source, the beam dynamics design of the RFQ was carried out with a new code LINACSrfq which can treat space charge effectively due to equipartitioning design strategy. Another feature of the RFQ is its high energy gain in two-meter long which will be described in detail. Construction of the RFQ cavity and the 100MHz/250kW amplifier has been completed and ready for test. A laser ion source is being tested. The assembling of the whole system including the ion source, the RFQ, the beam analyzing and diagnostic system is being done. Preliminary test results will be presented.
Soreq NRC, Yavne
The SARAF 4-rod RFQ is operating at 176 MHz, designed to bunch and accelerate a 4 mA CW deuteron/proton beam to 1.5 MeV/u. The electrodes voltage for accelerating deuterons is 65 kV, a field of 22 MV/m. The RFQ injected power is induced by a loop coupler. The power needed to achieve this voltage is 250 kW, distributed along the 3.8 m RFQ length. This power density is approximately 3 times larger than that achieved in other 4-rod RFQs. At high power, local high surface currents in the RFQ might cause overheating which will lead to out-gassing and in turn to sparking. We used CST MWS to simulate the RF currents and fields in a 3D detailed model of the SARAF RFQ. The correct eigenmode was reproduced and both Qe and Qo are consistent with the measured values. The heat load generated by the simulated surface currents at critical areas along the RFQ was the input for thermal analysis using Ansys. Detailed results reproduced the experimental observation of several overheated regions in the RFQ, including the end flanges and the plungers. Further results predicted overheating at different regions which were subsequently measured and are now being improved by additional cooling.
TUB, Beijing
LANL, Los Alamos, New Mexico
NUCTECH, Beijing
CERN, Geneva
We present, in this paper, the physics and mechanical design of a Radio Frequency Quadrupole (RFQ) accelerator for the Compact Pulsed Hadron Source (CPHS) at Tsinghua University. The 3-meter-long RFQ will accelerate protons from 50 keV to 3 MeV at an RF frequency of 325 MHz. In the physics design we have programmed the inter-vane voltage as a function of beam velocity, to optimize the performance of the RFQ, by tailoring the cavity cross section and vane-tip geometry as a function of longitudinal position while limiting the peak surface electric field to 1.8 Kilpatrick. There will be no Medium-Energy-Beam-Transport (MEBT) following the RFQ. The focusing at the high energy end of the RFQ and at the entrance of the DTL have been tailored to provide continuous restoring forces independent of the beam current. In simulations of the proton beam in the RFQ, using the code PARMTEQM, we observe transmission exceeding 97%. The RFQ is mechanically separated into three sections to facilitate machining and brazing. We have machined a test section and the final RFQ accelerator is now under construction. We will describe the status of the RFQ system in this paper.
* K. R. Crandall et al., RFQ Design Codes, LA-UR-96-1836.
ORNL, Oak Ridge, Tennessee
University of Tennessee, Knoxville, Tennessee
In radio frequency quadrupole (RFQ) structures, the fundamental quadrupole mode is used for focusing and acceleration of ion particles. The fields are maintained to have negligible interference with other unwanted modes of the structure using mode suppressors of different types especially in vane type RFQs that require dipole mode separation. The field distribution on the beam axis is usually measured and referenced using multiple loop-type magnetic probe antennas on the wall along the structure. Since the structures are equipped with many slug tuners on the outer wall for correction of fields, the tuner-probe interference can be a concern. In order to investigate the mode separation properties of the commonly used mode suppressors and the accuracies in field distribution with respect to localized perturbation due to the tuners, a systematic 3D simulation was carried out using a full-scale model of the SNS RFQ.
Fermilab, Batavia
The Fermilab High Intensity Neutrino Source program has built and commissioned a pulsed 325 MHz RFQ. The RFQ has successfully accelerated a proton beam at the design RF power. Experiences encountered during RFQ conditioning, including the symptoms and cause of a run-away detuning problem, and the first beam results are reported.
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
KEK, Ibaraki
The J-PARC RFQ (length 3.1m, 4-vane type, 324 MHz) accelerates a negative hydrogen beam from 0.05MeV to 3MeV toward the following DTL. We started the preparation of a new RFQ as a backup machine. The new cavity is divided by three unit tanks in the longitudinal direction. The unit tank consists of two major vanes and two minor vanes. A numerical controlled machining with a conventional ball-end-mill has been chosen for the vane modulation cutting instead of the wheel shape cutter. In this presentation we will report the machining procedure, the results of the vane machining, RF properties, and some topics during the fabrication.
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
KEK, Ibaraki
The J-PARC RFQ (length 3.1m, 4-vane type, 324 MHz) accelerates a negative hydrogen beam from 0.05MeV to 3MeV toward the following DTL. We started the preparation of a new RFQ as a backup machine. The new cavity is divided by three unit tanks in the longitudinal direction. The unit tank consists of two major vanes and two minor vanes. A one-step vacuum brazing of a unit tank has been chosen to unite these four vanes together with the flanges and ports. In this presentation we will report the results of the vacuum brazing with the dimension accuracy and an RF property.
BNL, Upton, Long Island, New York
Kyushu University, Department of Applied Quantum Physics and Nuclear Engineering, Fukuoka
JAEA/TARRI, Gunma-ken
It was proved that direct plasma Injection Scheme (DPIS) is an efficient way to accelerate high current highly charged state heavy ion beam. More than 50 mA (peak current) of various heavy ion beams were accelerated in BNL, RIKEN and TITech. However, it was rather difficult to obtain longer pulse especially for highly charged particles. To induce highly charged states ions, a high plasma temperature is required at the laser irradiation point and the high temperature automatically gives a very fast expansion velocity of the plasma. This shortens the ion beam pulse length. To compensate the shorter ion pulse length, we can extend the plasma drift length, but it will dilute the brightness of the plasma since the plasma expands three dimensionally. To avoid the reduction of the brightness, a simple long solenoid was applied to confine the diverging angle of the plasma. In the conference, this new technique will be explained and the latest results will be shown.
LBNL, Berkeley, California
Project X is a proposed multi-MW proton facility at Fermi National Accelerator Laboratory. It is the key element for future accelerator complex development intended to support world-leading High Energy Physics (HEP) programs. The Project X front-end would consist of H- ion source(s), a low-energy beam transport (LEBT), radio-frequency quadrupole (RFQ) accelerator(s), and a medium-energy beam transport (MEBT). To support current and future HEP experiments at Fermilab, a CW RFQ is required. One of the chosen RFQ designs has a resonant frequency at 325 MHz. The RFQ provides bunching of the 10 mA H- beam with acceleration up to 2.5 MeV and wall power losses of less than 250 kW. LBNL is currently developing the early designs for various components in the Project X front-end. The RFQ design concept and the preliminary RF and thermal analyses are presented here.
KAERI, Daejon
A Radio Frequency Quadrupole (RFQ) has being desinged for the post-acceleration of radio isotope beams from a radio isotope beam production system such as an isotpe separation on line (ISOL) or an in-flight separation. For simple and efficient beam acceleration, a chrage breeding system such as an electron cyclotron resonance ion source (ECRIS) or electron beam ion source (EBIS) The RFQ will operate at a resonant frequency of 70MHz at cw mode, and accelerate the beams to 300keV/nucleon. In the conference we will present the design of the RFQ.
Siemens Med, Erlangen
Siemens DK, Jyllinge
Siemens is currently preparing, installing and commissioning three IONTRIS particle therapy accelerator systems - two in Germany, in Marburg and Kiel, and one in Shanghai, China. Siemens IONTRIS is based on a synchrotron to accelerate protons and carbon ions for clinical applications up to 250 MeV resp. 430 MeV/u. The injector part consists of an RFQ to accelerate protons and light ions up to 400 keV/u followed by an IH-cavity, wherein the particles achieve 7 MeV/u. The results of the commissioning of the RFQ in the test facility in Denmark will be presented.
*Particle Therapy is a work in progress and requires country-specific regulatory approval prior to clinical use.
INFN/LNL, Legnaro (PD)
INFN- Sez. di Padova, Padova
In order to attain the stringent goals that assure the required performances of the IFMIF-EVEDA RFQ in terms of field uniformity, Q-value and RF-induced heat removal capability, the study of the 3D details of the cavity is particularly important. In this paper the main issues regarding the design of the slug tuners, cavity ends and vacuum grids are addressed, as well as the related optimization procedure.
INFN/LNL, Legnaro (PD)
The TRASCO RFQ will accelerate the 40 mA cw proton beam from the ion source to the energy of 5 MeV, for the production of intense neutron fluxes for interdisciplinary applications. The RFQ is composed of six modules of 1.2 m each, assembled by means of ultra high vacuum flanges. The structure is made of OFE copper and is fully brazed. RFQ modules were manufactured in CINEL Scientific Instruments S.r.l. while chemical treatments and brazing were done at CERN. This paper covers the brazing results of the last four modules and low power tests performed for preparation to the high power test of the first electromagnetic segment.
INFN- Sez. di Padova, Padova
INFN/LNL, Legnaro (PD)
In the framework of the IFMIF/EVEDA project, the RFQ is a 9.8 m long cavity, with very challenging mechanicals specifications. In the base line design, the accelerator tank is composed of 18 modules that are flanged together. An RFQ prototype, composed of 2 modules with a reduced length, aimed at testing all the mechanical construction procedure is under construction. In this paper, the thermo-mechanical study by means of 2D thermo structural and 3D fluid-thermal-structural simulations will be described. The measurements made with a cooling water circuit on a part of the RFQ prototype and the comparison with fluid thermal simulation will be reported.
ANL, Argonne
An integral part of the ongoing ATLAS efficiency and intensity upgrade is an RFQ to replace the first section of the existing injector. The proposed RFQ is 3.8 m long made of 106 cells with 30 keV/u input energy and 260 keV/u output energy. The RFQ was designed using the DesRFQ code which produces a file consisting of the length, modulation and the 8 coefficients of the 8-term potential for every cell. To independently check the design we created full 3D models of the RFQ including cell modulation in both Micro-Wave Studio (MWS) and Electro-Magnetic Studio (EMS). The MWS model was used to verify the phasing and energy gain along the RFQ using particle tracking and the EMS model was used to extract the electric field cell by cell assuming the electrostatic approximation. A very good agreement was obtained between the full 3D model and the 8-term potential description in TRACK. In addition to the standard sinusoidal vane profile we studied the option of converting the cells with maximum modulation (~ 40 cells) into trapezoidal cells. The output energy was increased from 260 keV/u to ~ 300 keV/u with minimal change to beam dynamics. This option is the final RFQ design.
RAS/INR, Moscow
Due to dispersion properties 4-vane RFQ cavity without resonant coupling is a thermally unstable structure. With deterioration of balance for local detuning there is a possibility for runaway in the field distribution and related thermal effects. It can results, in principle, in irreversible plastic deformations and cavity frequency shift. Both the increment and the threshold of instability are proportional to the average dissipated RF power. This possibility is more probable for long RFQ cavities. Also particularities for the cavity ends design are important. Some general features of this effect are discussed qualitatively and illustrated with simulations.
IHEP Beijing, Beijing
The CSNS is a spallation neutron research facility being built at Dongguan in Guangdong Province [1]. The 324MHz Alvarez-type Drift Tube Linac (DTL) will be used to accelerate the H- ion beam from 3 to 80.0 MeV with peak current 15mA. The R&D of a prototype structure at the low energy section of DTL is taking place at IHEP. The first unit tank 2.8m in length for the energy range from 3 to 8.88 MeV and 28 drift tubes containing electromagnetic quadrupoles are developed. This paper introduces the R&D status of the tank and 28 drift tubes. The measurement results of the focusing quadrupoles are also presented.
IHEP Beijing, Beijing
In the 324MHz CSNS Drift Tube Linac, the electromagnetic quadrupoles will be used for transverse focusing. The R&D of the quadrupole for the lower energy section of the DTL is a critical issue because the size of the drift tube at this section is so small that it is not possible to apply the conventional techniques for the fabrication. Then the electromagnetic quadrupoles containing the SAKAE coil and a drift tube prototype containing an EMQ have been developed. In this paper, the details of the design, the fabrication process, and the measurement results for the quadrupole magnet are presented.
IHEP Beijing, Beijing
In the China Spallation Neutron Source project [1], the 324HMz Alvarez-type DTL will be used to accelerate the H- ion beam from 3 to 80.0MeV. The DTL linac has been designed as four tanks and the electromagnetic quadrupoles will be used for the transverse focusing inside the drift tubes. The geometries of the DTL cells were optimized by using SUPERFISH and the beam dynamics simulation was performed with PARMILA code. In this paper both the physical design and the engineering designs are presented.
IMP, Lanzhou
The separated function DTL in SSC(Separated Sector Cyclotron)-linac is being designed. According to the design requirements, 238U34+ ions are accelerated from 0.143MeV/u to 0.976MeV/u throught the DTL. The method coupling DAKOTA(Design Analysis Kit for Optimization and Terascale Application) and beam simulation code BEAMPATH is used to analyze tolerance of the structure. The tolerance of beam parameters to various type of random errors and misalignment are studied with Monte Carlo simulation,so as to de ne the engineering tolerance and alignment. In this paper, the beam dynamics simulation and the tolerance analysis of the SSC-linac are presented.
Southwest University of Science and Technology, Mianyang, Sichuan
A system ADS study program has been proposed and organized by Chinese Academy of Sciences. As part of the study program, concept design of a 10mA 1.5GeV Continue Wave (CW) superconducting proton linac has been started in the Institute of High Energy Physics (IHEP). In this paper the design of the 325MHz part of this linac, which is composed of a room temperature Radio Frequency Quadrupole (RFQ), eight 4-cell room temperature Cross bar H-type (CH) cavities and three kinds of spoke cavities with total number of 78, is presented. The main parameters and detailed beam dynamic simulation results of the CH and spoke section are introduced.
CERN, Geneva
The design of the Drift Tube Linac (DTL) for the new linear accelerator Linac4 at CERN has been made ready for production: H–ion beams of up to 40 mA average pulse current are to be accelerated from 3 to 50 MeV by three RF tanks operating at 352.2 MHz and at duty cycles of up to 10%. In order to provide a margin for longitudinal matching from the chopper line, the longitudinal acceptance has been increased. The synchronous phase starts at -35° in tank1 and ramps linearly to -24° over the tank while it went from -30° to -20° in the previous design. The accelerating gradient has been lowered to 3.1 MV/m in Tank1 and increased to 3.3 MV/m in Tank2 and Tank3 for a better distribution of RF power between tanks that is compatible with a mechanical design. To make the transverse acceptance less sensitive to alignment and gradient errors, the focusing scheme has been changed to FFDD over all 3 tanks. Design features that were demonstrated in earlier reports have been improved for series production. Results of high power RF tests of the DTL prototype equipped with PMQs are reported that test the voltage holding in the first gaps in presence of magnetic fields.
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
Transverse emittance growth was observed in J-PARC Drift Tube Linac (DTL). In order to suppress the growth, we searched for optimum parameters at MEBT1, by measuring transverse emittance using four wire scanner monitors at the exit of DTL. At 15 mA peak beam current in Dec 2009, horizontal and vertical rms emittance was reduced by 12 % and 10 %, respectively, by setting the amplitudes of the first and second bunchers to 120 % and 90 % with respect to the designed settings. The resulting normalized horizontal and vertical emittance was 0.230 and 0.205 pi mm mrad. At 20 mA in Jan 2010, horizontal and vertical rms emittance was reduced by 17 % and 10 %, respectively, by setting the amplitudes of the first and second bunchers to 110 % and 80 % with respect to the designed settings. The resulting normalized horizontal and vertical emittance was 0.273 and 0.253 pi mm mrad. At 15 mA, we further reduced the horizontal and vertical emittance to 0.171 and 0.200 pi mm mrad by increasing the eighth quadruple magnet field at MEBT1 by 20 % to the designed value. The measured transverse emittance dependence on buncher electric field and quadruple magnetic field will be compared with simulation.
JAEA/LINAC, Ibaraki-ken
KEK, Ibaraki
The operation of the DTL and the Separated type DTL (SDTL) of the J-PARC started in November 2006. The DTL and SDTL are currently running stable and accelerating the beam. For stable operation of the DTL/SDTL, We have done maintenance of the equipments, like an RF coupler, and improved the troubles. In this paper, we will present the operation experiences of the DTL and the SDTL.
KEK, Ibaraki
JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
X-ray radiation from the SDTL of J-PARC linac has been observed with the beam loss monitor by the cavity. The results show that the X-ray intensity depends not only on the RF power level of the tank but also on the RF structure of the tank. In the paper we will show the results of the investigation for the origin of the X-ray radiation from the tank.
RIKEN Nishina Center, Wako
SHI, Tokyo
A new linac injector, which will be exclusively used for the RIKEN RI-Beam Factory, has been constructed to increase the beam intensity of very heavy ions such as xenon and uranium. The injector system consists of a superconducting ECR ion source, RFQ linac, three DTLs, and beam transport system including strong quarupole magnets and beam bunchers. Two DTL resonators were newly designed while existing devices including the RFQ* were modified to the other resonators. Direct coupling scheme was adopted for the rf-sytems of the DTLs, where the design study was successfully perfomed by using the MWS code. This paper focuses on the design procedure of the DTLs and RFQ as well as the results of their low and high power tests.
*H. Fujisawa, Nucl. Instrum. and Methods A345 (1994) 23-42.
TUB, Beijing
TechSource, Santa Fe, New Mexico
NUCTECH, Beijing
CIAE, Beijing
CERN, Geneva
IHEP Beijing, Beijing
The CPHS project in Tsinghua University plans to construct a 13 MeV linear accelerator to deliver a pulsed proton beam having an average beam current of 2.5 mA. A Drift Tube Linac (DTL), following a Radio Frequency Quadrupole accelerator(RFQ), will accelerate protons from 3 to 13MeV. The accelerating field and phase will be ramped to match the longitudinal restoring forces at the end of the RFQ. Likewise, the transverse focusing forces, provided by permanent-magnet quadrupole lenses (PMQs) will be programmed to match the transverse restoring forces at the end of the RFQ to avoid missmatch and avoid parametric resonances. We will present the main physics design parameters of CPHS DTL and describe the properties of the resonant cavity. We plan to apply electron beam welding technology exclusively in the fabrication of the drift tubes and will present the test results from our engineering prototyping program.
INFN/LNL, Legnaro (PD)
CERN, Geneva
Post Couplers (PC's) are devices used in order to reduce the effect of perturbations on the operating mode of a DTL, using the resonant coupling stabilization method. In this paper an equivalent circuit for a DTL equipped with PC's is presented, together with a 3D simulation analysis, which can explain the post coupler stabilization principle and define a new tuning strategy for DTL cavities. The PC tuning procedure based on the equivalent circuit and on frequency measurements has been tested and validated with measurements on the Linac4 DTL aluminum model.
ITEP, Moscow
Intense heavy ion beam is very efficient tool to generate high energy density states in macroscopic amounts of matter. As result it enables unique methods to study astrophysical processes in the laboratory under controlled and reproducible conditions. For advanced experiments on high energy density physics the cylindrical target irradiated by hollow cylindrical beam is required. This combination provides extremely high densities and pressures on the axis of imploding cylinder. A new method for RF rotation of the ion beam is applied for required hollow beam formation. The RF system consisting of two four-cell H-mode cavities is under development for this purpose now. The cavities frequency has been chosen 298 MHz, which is sufficient for uniform target illumination at 100 ns pulse duration. The deflecting electrodes shape has been optimized to provide the uniform deflection of all particles in beam's cross-section. The prototype of the deflector cell was constructed. A measured electro-dynamics characteristic is presented. As well frequency corrections methods are considered in this paper.
Soreq NRC, Yavne
The SARAF front end is composed of a proton/deuteron ECR ion source and a LEBT to match the beam to a 4-rod RFQ. The LEBT is consisting of an analyzing magnet, an aperture, three magnetic solenoid lenses and a diagnostic system. The typical operation vacuum, downstream the analyzing magnet, is of the order of 10-6 mbar at 5 mA analyzed beam current. In the emittance measurement we identify a beam of secondary-species particles, differently affected by the solenoid and so arriving with a different phase-space profile at the emittance detector. The secondary beam is the result of a charge exchange interaction in which an ion interacts with residual gasses in the beam line, most likely hydrogen gas coming from the ion source, and become neutral. For 20 keV protons colliding with H2 the calculated ion neutralization rate is 1%/m/10-6 mbar. Since the neutral portion of the beam is not affected by the magnetic focusing / steering elements, a none concentric neural and ion beams in the phase-space is a measure of mistuned beam or misalign magnets. These effects were proved and followed by beam dynamics simulation and are used to match the beam to the RFQ.
JAEA/J-PARC, Tokai-mura
JAEA, Ibaraki-ken
KEK/JAEA, Ibaraki-Ken
Residual gas in beam transport line essentially affects the beam loss and residual radiation on the accelerator. J-PARC linac is usually operated under 1.0 ·10-6 to 1.0 ·10-5 Pa in SDTL and A0BT sections. In this situation, no serious beam loss was observed during the beam operation. In future development of J-PARC linac, because the peak beam energy and output will be increased, it is getting more serious problem. Before the development, it is important to understand a cause of beam loss and relation between beam loss and residual gas pressure. We measured beam loss at the normal and worse vacuum condition in both SDTL and A0BT sections. The result indicates that the beam loss depends on the residual gas pressure and position where the beam loss occurs is about 20 to 30 meter downstream. This suggests the optimum position for installation of vacuum system to minimize the beam loss. In this paper, we describe the experimental result and its discussions. In addition, the cause of the beam loss is considered to be a stripping from negative hydrogen ions to neutral hydrogen atoms. This mechanism is also discussed in this paper.
JAEA/J-PARC, Tokai-mura
KEK, Ibaraki
J-PARC, KEK & JAEA, Ibaraki-ken
JAEA, Ibaraki-ken
JAEA/LINAC, Ibaraki-ken
Since November, 2007, J-PARC Linac has been operated at 7.2kW beam power. During the operation, beam losses possibly caused by the H0 particles generated by the interaction between H- beam and residual gas in the transport line were observed in the SDTL (Separated-type Drift-Tube Linac) section. In the linac operation, Ar-CO2 gas proportional counters are employed for the measurement of beam loss, but they are also sensitive to background noise of X-ray emitted from RF cavities. In this section, protons, secondary hadrons and gamma rays would be mainly generated as a beam loss, but it is not easy to estimate real beam loss using the proportional counter. The plastic scintillation counters with less X-ray sensitivity and 3He proportional counters with high thermal neutron sensitivity will be also employed to measure the beam loss. The combination of these detectors would bring more accurate beam loss measurements with suppression of X-ray noise. A measurement of emission position and angle distributions of protons due to H- beam loss is being planed. This result would lead to clarify the source of beam loss. This paper reports status of beam loss evaluation using these detectors.
Fermilab, Batavia
Development of solenoid-based focusing lenses for transport channel of an R&D linac front end at FNAL is in its final stage. Lenses for the room temperature section of the linac are assembled in individual cryovessels and certified using a devoted stand. During this certification process, for each lens, position of its optical axis relative to the cryovessel is found in the warm and cold state. Lenses for the superconducting sections are ready for production, and development of a cryomodule to house multiple superconducting lenses and RF cavities is in progress. Studies were also conducted to measure fringe magnetic field of a lens in a cryomodule, to investigate a laser-based method of alignment, and to evaluate the extent of beam quality degradation due to imperfections in lens construction and alignment. This report presents some results of these studies.
Fermilab, Batavia
Fermilab is currently focusing its efforts toward the development of Stainless Steel (SS) helium vessels for its 1.3 GHz SRF cavities. The objective is to transition towards the concept of using SS helium vessels to dress the bare SRF cavities, thereby paving way for significant cost reduction and efficient production techniques for future accelerators. The biggest challenge has been to design a reliable interface between the niobium cavity end group and the stainless steel end flange that encloses the helium vessel. Fermilab has been pursuing a brazed joint design to allow this transition. Additional design challenges associated with this transition are ensuring proper cooling of the cavity, compensating for the difference in thermal contraction between the SS helium vessel and niobium cavities, and also modification of the tuning procedure and ensuring the safety and reliability of the blade and piezo tuners. Current efforts on the qualification of the niobium-SS braze joint, finite element simulations of the thermal design aspects, bench testing of actual cavity displacements, and study of the effects on the tuners will be presented.
Fermilab, Batavia
Fermilab has produced two cryomodules for superconducting RF (SRF) applications to date. The first of these is an ILC prototype containing eight 1.3 GHz Tesla-type cavities and a superconducting quadrupole. This cryomodule is of the 'Type 3+' design developed by the TESLA collaboration. The assembly of this cryomodule was accomplished at Fermilab with much assistance from DESY and INFN-Milano. The cryomodule was tested at Fermilab in the summer of 2010. The second cryomodule produced at Fermilab contains four 3.9 GHz nine-cell cavities. The cavities and cryomodule were designed at Fermilab; the design concepts are quite similar to the 1.3 GHz Type 3+ cryomodule. This cryomodule was shipped to DESY, tested, and is now operating as part of a third-harmonic system in the FLASH facility. Fermilab plans to build five more 1.3 GHz cryomodules over the next several years for a total of six, which will be installed and operated in the New Muon Lab beam test facility at Fermilab.
KEK, Ibaraki
Cryomodule tests of four Tesla-like superconducting cavities is under preparation in the S1-Global project at KEK. Assembly of the cryomodule was started in January 2010, and the installtion in the STF tunnel was completed in April. First cool-down tests are scheduled in June. The low rf power tests of the Tesla-like cavities will be carried out in July. The high rf power tests are scheduled between September and December, 2010.
JINR, Dubna, Moscow Region
The results obtained by the JINR/Dubna-RFNC/Sarov-FNAL/Batavia-INFN/Pisa in designing the fourth-generation cryomodule for the ILC are reported. A technology for making a bimetallic Ti+SS tube transition element by the explosion welding method has been developed and implemented for the first time. All Ti+SS samples were subjected to the metallografic analysis and tested for strength and leaks at different cryogenic temperatures. The leak rate at 1.8K was <10(-11)Pa.m(3)/s.For redesign cryomodule helium vessel we developed Nb+SS transition elements using explosion welding technology. Preliminary tests shown reliable strehgth and density of joint Nb+SS bonds. Upper limit of leak rate is (3-5).10(-10)atm.cc/s.
NSCL, East Lansing, Michigan
Michigan State University is developing cryomodules for two projects: a 3 MeV per nucleon superconducting linac for re-acceleration of exotic ions (ReA3, under construction, requiring 4 cryomodules), and a 200 MeV per nucleon driver linac for the Facility for Rare Isotope Beams (FRIB, under design, requiring 52 cryomodules). The first two ReA3 cryomodules contain a total of seven quarter-wave resonators for beta = 0.041 and five superconducting solenoids (9 T). These cryomodules have been fabricated and installed, with testing underway. The third ReA3 cryomodule (requiring eight QWRs for beta = 0.085 and three solenoids) is being fabricated. A fourth ReA3 module consisting of a single quarter-wave resonator will be used for matching. A prototype cryomodule for FRIB is being designed for two beta = 0.53 half-wave resonators and one solenoid. The experience so far with system performance of the cryomodules will be described in this paper. Topics will include cavity performance, magnetic shielding, microphonics, cavity tuning, input coupler performance, and thermal loads.
RAS/INR, Moscow
The monitor to measure a transverse cross section of the accelerated beam has been developed and implemented in INR Linac. Operation of the monitor is based upon utilization of residual gas ionization. Ion flux cross section after extraction of the ions from the beam line by electrostatic field and subsequent energy separation in electrostatic analyzer reproduces a transverse cross section of the accelerator beam. Aμchannel plate intensifier followed by a phosphor screen is used to observe ion cross section. The image is optically transmitted to a CCD camera installed remotely and shielded for protection. The monitor enables to observe beam cross section, beam profiles and beam position, as well as their evolution in time within a wide range of beam intensities and energies. Monitor operation and parameters are described. Some experimental results are presented.
ANL, Argonne
An emittance meter based on a pepper-pot coupled to a CsI (Tl) scintillator has been developed over the last several years [1] at Argonne National Laboratory. A compact version of such a probe for on-line emittance measurements has been designed, built and installed into the low energy beam transport (LEBT) line of the Argonne Tandem Linac Accelerator System (ATLAS) and also downstream of the gas catcher of the recently commissioned Californium Rare Isotope Breeder Upgrade (CARIBU). The probe has demonstrated the capability to measure emittance of ion beams with a current density as low as 10 nA/cm2. Systematic emittance measurements in the ATLAS LEBT for different ion species have been done and results will be presented. The probe, based on a pepper-pot coupled to an MCP viewing system, has been designed and built to measure the emittance of low intensity (102-106 ions/s) radioactive CARIBU ion beams.
[1] S. Kondrashev et al. Development of a pepper-pot emittance probe and its application for ECR ion beam studies. Nuclear Instruments and Methods in Physics Research A 606, 2009, pp. 296-304.
ORNL, Oak Ridge, Tennessee
We present practical aspects of measuring beam profiles and applications using the profile data. Standard applications include (RMS) beam size calculation, Courant-Snyder parameter calculation, and beam matching. Each application becomes increasingly model dependant relying upon results of the preceding application. Because of the cascade of interdependence, of obvious concern is measurement error which propagates throughout the calculations. Also important is the accuracy of the beam model used to make calculations from measurement results; doubly so for matching where the model both estimates Courant-Snyder parameters and predicts new magnet strengths. Not as obvious are complications introduced by the long pulse nature of the SNS linac. Currently, we can sample the beam only through a 50 microsecond window along a macro pulse lasting up to 1 millisecond. Consequently the measurements available are not necessarily representative of the whole beam. Presented are quantitative results on measurement error, model accuracy, and sampling location, how these quantities vary along the linac, and the ramifications on matching techniques.
ORNL, Oak Ridge, Tennessee
The latest modifications of the MEBT emittance scanner and the test results are presented. The scanner consists of a slit and harp placed in the MEBT section of SNS Linac with H- energy of 2.5 MeV. It was initially commissioned during the early days of SNS. The initial design allowed to get information about beam core but was incapable of getting precise data about halo. Several improvements in hardware and software were performed recently. They significantly increased signal to noise ratio, reduced harp wires electron coupling and increased scan speed. The latest measurements with the new system show a good agreement with the simulation results from simple models.
SNU, Seoul
NCC, Korea, Kyonggi
A bunch length detector has been designed and constructed, which can measure current distributions inside the beam bunch. The device measures secondary electrons that are emitted when the beam hits a negatively biased thin target wire. Two main components of the device are an rf deflector to deflect secondary electrons vertically in correlation with the rf time of the beam bunch, and microchannel plate to detect the electrons after spatial discrimination. Rf properties of the rf deflector were first numerically analyzed, and a full-scale cold model was built and tested using a network analyzer. Microchannel plate detector was tested using a beta-emitting isotope source. The electron optics were calculated to design the structure of the detector, and the actual detector will soon be constructed and tested using a cw proton beam from a cyclotron.
Soreq NRC, Yavne
The SARAF accelerator is designed to accelerate both deuteron and proton beams up to 40 MeV. Phase I of SARAF consists of a a 4-rod RFQ (1.5 MeV/u) and a superconducting module housing 6 half-wave resonators and 3 superconducting solenoids (4-5 MeV). The ions energy and energy spread were measured using the Rutherford scattering technique . This technique is used to tune the cavities to the desired amplitude and phase. The downstream HWR is used as a buncher and the beam energy spread as function of the bunching RF voltage is applied to estimate the longitudinal emittance. In this work, we present a longitudinal emittance measurement algorithm, which is based on the bunch energy spread as a function of the buncher's amplitude, similar to the standard algorithm that uses the bunches' temporal spread. The tuning and measured longitudinal parameters are in qualitative agreement with the predicted beam dynamics simulation.
TRIUMF, Vancouver
The post acceleration section of the ISAC radioactive ion beam (RIB) facility is composed of a radio frequency quadrupole (RFQ) followed by a drift tube linac (DTL), both room temperature machines, that serve a medium energy experimental area up to 1.8 MeV/u, and a superconducting linac (SCLINAC) that serves a high energy experimental area. This SCLINAC, composed of forty quarter wave resonators housed in eight cryomodules, is capable of a total accelerating voltage of circa 40 MV. Since each cavity is phased independently at the maximum operational voltage, the final energy depends on the mass to charge ratio of the accelerated species. In order to deliver energies higher than 5 MeV/u we need to monitor the beam current as mandated by our operating license. The current monitor system (CMS) is composed of two non intercepting and one partially intercepting monitor. The signals from these three monitors are processed in a single control system that provides a go signal to the Safety system enabling beam delivery. The CMS system allows to exploit the SCLINAC to its full potential. In this paper we will present both hardware configuration and software control of the CMS.
FRIB, East Lansing, Michigan
NSCL, East Lansing, Michigan
The Facility for Rare Isotope Beams (FRIB) at Michigan State University will utilize a high power, heavy-ion linear accelerator to produce rare isotopes in support of a rich program of fundamental research. The linac will consist of a room temperature-based front-end system producing beams of approximately 0.3 MeV/u. Three additional superconducting linac segments will produce beams of >200 MeV/u with a beam power of up to 400 kW. Because of the heavy-ion beam intensities, the required diagnostics will be largely based on non-interceptive approaches. The diagnostics suites that will support commissioning and operation are divided into lower energy <0.3 MeV/u front-end and higher energy driver linac systems (<200 MeV/u for uranium). The instruments in the driver linac include strip-line BPM, toroid, BCM, and 3-D electron scanners to measure rms beam size. A desired availability of >90% and an aggressive commissioning schedule lead to some challenges in beam diagnostics requirements that will be addressed in this paper. We are committed to using an architecture common with the rest of FRIB for the data acquisition and timing which will also be discussed in this paper.
DESY, Hamburg
The European XFEL, currently under construction at the DESY site in Hamburg, require high precision orbit control in the long undulator sections and in addition in some other locations of the machine, like bunch compressors, matching sections, or for the intra bunchtrain feedback system. Due to the pulsed operation of the facility the required high precision has to be reached by single bunch measurements. So far only cavity BPMs achieve the required performance and will be used at the European XFEL. We report on the development of two types of cavity BPMs for the intersection of the undulators with 10 mm beam pipe and for sections with a standard beampipe diameter of 40.5 mm. The prototypes for both types show the properties as expected for simulation results. The paper further concentrates on the industrialisation process. It points out some traps and their cures during the production process.
DESY, Hamburg
The European XFEL is a 4th generation synchrotron radiation source, under construction in Hamburg. Based on different Free-Electron-Laser and spontaneous sources, driven by a 17.5 GeV superconducting accelerator, this international facility will provide several user stations with photons simultaneously. Due to superconducting technology high average as well as peak brilliance can be delivered. Flexible bunch pattern are possible for optimum tuning to the experiments demands. This paper will present the current status of the electron beam diagnostics. An overview of the entire system will be given, as well as details on the development of the main systems like BPM, charge and transmission diagnostics, beam size and beam loss monitor systems will be presented. Furthermore, results of first measurements with XFEL prototypes in FLASH will be shown.
DESY Zeuthen, Zeuthen
YerPhI, Yerevan
NSC/KIPT, Kharkov
Recent successes in existing linac based FEL facilities operation and improvements in future FEL designs became possible due to detailed research in high-brightness electron beam production. The Photo Injector Test facility in Zeuthen (PITZ) is the DESY center for electron source characterization and optimization. New slice emittance diagnostics was recently commissioned at PITZ. In the measurement approach a bunch is accelerated off-crest in the accelerating cavity downstream the gun, a part of the bunch is selected after a dipole with a slit perpendicular to the dispersive direction, and the transverse emittance of the bunch part is measured using a quadrupole or a slit scan. Test measurement results are presented for 1 nC charge, flat-top and Gaussian longitudinal laser shapes.
DESY Zeuthen, Zeuthen
INRNE, Sofia
The Photo-Injector Test Facility at DESY in Zeuthen, PITZ, is dedicated to development of high brightness electron sources for linac-based FELs like FLASH and the European XFEL. A key parameter to judge on the beam quality for an FEL is the transverse phase space distribution, wherefrom the PITZ beamline is equipped with three Emittance Measurement Systems as the only dedicated to that apparatus. In 2010 the diagnostics has been upgraded with a module for tomographic reconstruction comprising three FODO cells, each surrounded by two observation screens. The anticipated advantages of tomographic measurements are improved resolution for low charge beams and ability to evaluate both transverse planes simultaneously. Major operational challenges are the low beam energies the module will be used with - 15 - 30 MeV, strong space charge effects for high bunch charges and, consequently, difficulties to match the beam into the optics of the lattice. This contribution presents studies on the performance of the module for different initial conditions as bunch charge and temporal laser pulse shape. Influence of residual noise on the quality of the reconstructed phase space is discussed.
CEA, Gif-sur-Yvette
CERN, Geneva
Uppsala University, Uppsala
PSI, Villigen
To achieve high luminosity in CLIC, the accelerating structures must be aligned to an RMS accuracy of 5 μm with respect to the beam trajectory. Position detectors called Wakefield Monitors (WFM) are integrated to the structure for a beam based alignment. This paper describes the requirements of such monitors. The development plan and basic feature of the WFM as well as the accelerating structure working at 12 GHz and 100 MV/m are shortly described. Then we focus on detailed electromagnetic simulations and design of the WFM itself. In particular, time domain computations are performed and an evaluation of the intrinsic resolution is done for two higher order modes at 17 and 24 GHz. The mechanical design of the accelerating structure with WFM is also presented. Precise machining with a tolerance of 2.5 μm and a surface roughness of 0.025 μm is demonstrated. The fabrication status of three complete accelerating structures with WFM is finally presented for a feasibility demonstration with beam in CTF3 at CERN.
JAI, Egham, Surrey
CERN, Geneva
Compact Linear Collider (CLIC) is a multi-TeV electron-positron collider for particle physics based on an innovative two-beam acceleration scheme. The CLIC Test Facility 3 (CTF3, CERN) aims to demonstrate feasibility of this concept. The monitoring of a longitudinal profile will be very important for the CLIC. The optimization of the longitudinal charge distribution in a bunch is crucial for the maximisation of the luminosity and also for an optimal performance of a CLIC drive beam. A setup for the investigation of Coherent Diffraction Radiation (CDR) from targets with various configurations as a tool for non-invasive longitudinal electron beam profile diagnostics has been designed and installed in the CRM line of the CTF3 [1, 2]. In this report we present the status of the experiment and results on interferometric measurements of CDR from a single target configuration. Studies on downstream background contribution in the CRM line have been performed. Recently we have upgraded the system by installing a second target. In this report we shall also demonstrate the results on simulations of CDR spatial distribution from the two target configuration.
[1] M. Micheler et al., Longitudinal Beam Profile Measurements at CTF3 using CDR, PAC'09, "**".
[2] M. Micheler et al., Longitudinal beam profile monitor at CTF3 based on CDR, RREPS-09, "**".
CERN, Geneva
PSI, Villigen
IPM, Tehran
NU, Evanston
The CLIC Test Facility 3 (CTF3) is being built and commissioned by an international collaboration in order to test the feasibility of the proposed Compact Linear Collider (CLIC) two-beam acceleration scheme. The monitoring and control of the bunch length throughout the CTF3 complex is important since this affects the efficiency and the stability of the RF power production process. Bunch length diagnostics therefore form an essential component of the beam instrumentation at CTF3. This paper presents and compares longitudinal profile measurements based on transverse RF deflectors, Streak camera and non-destructive microwave spectrometry techniques.
CERN, Geneva
Université Blaise Pascal, Clermont-Ferrand
As part of the CERN LHC injector chain upgrade, LINAC4 will accelerate H- ions from 45 keV to 160 MeV. A number of wire grids and wire scanners will be used to characterize the beam transverse profile. This paper covers all monitor design aspects intended to cope with the required specifications. In particular, the overall measurement robustness, accuracy and sensitivity must be satisfied for different commissioning and operational scenarios. The physics mechanisms generating the wire signals and the wire resistance to beam induced thermal loads have been considered in order to determine the most appropriate monitor design in terms of wire material and dimensions.
PSI, Villigen
Phase I of the SwissFEL Injector Test Facility consists of a 2.6-cell S-band RF gun, a spectrometer, and a series of transverse beam diagnostic systems such as YAG screens, slit and pepper-pot masks. Its primary purpose is the demonstration of a high-brightness electron beam meeting the specifications of the SwissFEL main linac. Phase space characterization at beam energies up to 7 MeV, where space charge still dominates, is performed with YAG screens in combination with slit- and pinhole (pepper-pot) masks. Advanced image analysis is used to mitigate artefacts due to background, pixel readout noise, or dark current. We present our data analysis procedure for the slit scan method, with particular emphasis on image processing and its effect on the reconstructed emittance. Pepper-pot measurements using an independent analysis framework are used to cross-check the slit scan results.
PSI, Villigen
The SwissFEL Injector Test Facility consists of an RF gun, an accelerating section for a final energy of 250 MeV, and two diagnostics sections. Transverse profiles of the electron beam can be recorded at 27 locations by imaging fluorescent crystals that can be inserted into the beam. At 21 of these, the fluorescent screens are complemented by optical transition radiation monitors and wire scanners. Here, we will evaluate the performance of transverse profile monitors experimentally and numerically and compare the measured profiles with a numerical model of the accelerator. Profile monitors are used in conjunction with a slit and a pepper pot to determine the transverse phase space distribution of the bunches. Experimental measurements at the SwissFEL Injector Test Facility will be presented.
CAEP/IFP, Mainyang, Sichuan
Beam position monitors are very widely used in accelerator diagnostics. Beam direction measurement can provide very useful information. Azimuthal B-dots (commonly referred B-dots) can be used to measure the beam position because beam traveling off axis will generate dipole term of azimuthal magnetic field. Similarly, dipole term of axial magnetic field will be generated by the beam traveling with a direction not parallel with the pipe axis. In this paper, theoretical results are given to show how the axial B-dot works. And Mafia simulations are carried out to check the theoretical results. Simulation results agree with the theoretical results very well.
NSCL, East Lansing, Michigan
The US Department of Energy Facility for Rare Isotope Beams (FRIB) at Michigan State University includes a heavy ion superconducting linac capable of accelerating all ions up to uranium with energies higher than 200 MeV/u and beam power up to 400 kW. At an energy of approximately 17 MeV/u we plan to strip the beam to reduce the voltage needed in the rest of the linac to achieve the final energy. The design of the stripper is a challenging problem due to the high power deposited (approximately one kW) in the stripper media by the beam in the small beam size. One of the options being considered is a carbon foil stripper. We have developed a test chamber to study the thermal mechanical properties of different stripping media candidates (amorphous carbon, graphene, diamond). This chamber utilizes an electron beam to deposit powers similar to what the FRIB stripper will see in operation. The thermo-mechanical studies are a necessary condition but not sufficient. The effect of radiation damage must also be studied. We have utilized heavy ions (Pb) from the K500 cyclotron to study this issue. We present in this paper a summary of the requirements and the status of the studies.
NSCL, East Lansing, Michigan
BNL, Upton, Long Island, New York
ANL, Argonne
The US Department of Energy Facility for Rare Isotope Beams (FRIB) at Michigan State University includes a heavy ion superconducting linac capable of accelerating all ions up to uranium with energies higher than 200 MeV/u and beam power up to 400 kW. To achieve these goals with present ion source performance it is necessary to accelerate simultaneously two charge states of uranium from the ion source in the first section of the linac. At an energy of approximately 17 MeV/u we plan to strip the uranium beam to reduce the voltage needed in the rest of the linac to achieve the final energy. Up to five different charge states are planned to be accelerated simultaneously after the stripper. The design of the stripper is a challenging problem due to the high power deposited (approximately one kW) in the stripper media by the beam in a small spot. To assure success of the project we have established a research and development program that includes several options: carbon or diamond foils, liquid lithium films, gas strippers and plasma strippers. We present in this paper a summary of the requirements and a general description of the status of the different options.
LANL, Los Alamos, New Mexico
Muon accelerators are studied for future neutrino factory and muon colliders (NF/MC). On the other hand, a compact muon accelerator can be applicable to muon radiography which is a promising probe to investigate large objects. We worked on simulation studies on a compact muon linear accelerator. The designed linac has a large energy and a phase acceptance to capture lower energy pion/muon (10 - 100 MeV) than the NF/MC scenario and accelerates them to 200 MeV without any beam cooling. Our current design adopts 805 MHz zero-mode normal-conducting cavities with 35 MV/m peak field*. The superconducting solenoids are used to provide 5-T focusing field on the normal conducting cavities. We developed a Monte Carlo simulations code to optimize linac parameters. Muon energy loss and scattering effects at the aperture windows are included, too. The simulation showed that about 10 % of the pion/muon injected into the linac can be accelerated to 200 MeV. Further acceleration can be done with superconducting linac.
* S. Kurennoy et al., IPAC 2010.
MHI, Kobe
C-band RF pulse compressor is a device that generates high peak RF-power by saving, and compressing the RF-power output from the klystron. XFEL project is scheduled to be installed 64 pulse compressor units, 2009 of December we have completed the fabrication and RF measurement of all units. A high-power examination was conducted in the test stand at RIKEN. The RF output of the pulse compressor is 260 MW in peak value, and the acceleration gradient of the accelerating structure is achieved to be 40 MV/m.It reports on the mass production passage of these 64 C-Band RF pulse compressors and on the installation result of injector section.
Fermilab, Batavia
UCR, Riverside, California
IIT, Chicago, Illinois
Illinois Institute of Technology, Chicago, Illinois
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 thus a strategic R&D project for neutrino physics. It 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 the 2010 run, completed in August, the beam and most detectors have been fully commissioned. The time of the first measurement of input beam emittance is closely approaching. The plan of steps of measurements of emittance and emittance reduction (cooling), that will follow in 2011 and later, will be reported.
I submit this as chair of the MICE speakers bureau. If accepted, I will find a member of the collaboration that will register to the conference and present the contribution.