Search

In the collisions of proposed future circular colliders, like FCC-ee and CEPC, the beamstrahlung regime is classical, i.e. with an "Upsilon parameter" much smaller than 1. In the classical regime, for a constant electromagnetic field a simple relation exists between the average photon energy u and the average squared photon energy u², which is the same as for standard synchrotron radiation in storage rings. This relation breaks down, however, if the electromagnetic field is not constant in time and position, as is the case for a beam-beam collision. We derive an analytical expression for u²/u², considering the case of Gaussian-bunch collisions with crossing angle (and possibly crab waist). We compare our result with the photon energies obtained in beam-beam simulation for FCC-ee at beam energies of 45.6 GeV and 175 GeV, using the two independent codes BBWS and Guineapig. Finally, we re-optimize the FCC-ee parameters of a possible mono-chromatization scheme for direct Higgs production at 125 GeV, derived previously, by applying the refined expression for the rms photon energy., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

The DONES (DEMO oriented neutron source) project is aimed at constructing a DEMO of IFMIF to provide sufficient material damage [1]. In the SRF-Linac of this project, losses can cause harmful material activation and must be maintained much less than 1W/m. It's a challenge to keep losses at such a low level with high beam power and high space charge. This paper presents two designs of the DONES SRF-Linac, one with 4 cryomodules and another with 5 cryomodules. The design details to reduce the losses and the multi-particle simulation results will be shown. The errors studies for these results will also be discussed., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

SNRC and CEA collaborate to the upgrade of the SARAF accelerator to 5 mA CW 40 MeV deuteron and proton beams (Phase 2). CEA is in charge of the design, construction and commissioning of the MEBT line and the superconducting linac (SARAF-LINAC Project). The prototypes of the 176 MHz NC rebuncher, SC cavities, RF coupler and SC Solenoid-Package are under construction and their test stands construction or adaptation is in progress at Saclay. Meanwhile, the cryomodules and the global system just passed their Critical Design Reviews. This paper presents the status of the SARAF-LINAC Project at April 2018., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

IFMIF, the International Fusion Materials Irradiation Facility, is an accelerator-based neutron source that will use Li(d, xn) reactions to generate a flux of neutrons with a broad peak at 14 MeV equivalent to the conditions of the Deuterium-Tritium reactions in a fusion power plant. IFMIF is conceived for fusion materials testing. The IFMIF prototype linear accelerator (LIPAc) is jointly developed by Europe and Japan within the IFMIF EVEDA project: it is composed of an ion source, a LEBT, an RFQ, a MEBT and a SC linac, with a final energy of 9 MeV. The 4-vane Radio Frequency Quadrupole (RFQ), developed by INFN in Italy, will accelerate a 130 mA deuteron beam from 0.1 to 5 MeV in continuous wave, for a beam power of 650 kW. The 9.8 m long 175 MHz cavity is composed of 18 x 0.54 m long modules flanged together and aligned within 0.3 mm tolerance. The RFQ was completed, delivered and assembled at the Rokkasho site and is presently under extended RF tests. The second phase of beam commissioning (up to 2.5 MeV/u) was scheduled to start at the end of 2017. Several unexpected issues and incidents significantly delayed the original program, which is however proceeding step by step toward the full achievement of its goals., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

As the FAIR Project is proceeding, building designs have been frozen and the according work packages tendered. For the future FAIR main driver accelerator, SIS100, the 1.1 km long accelerator tunnel "T110", has been planned 17 m deep under ground. In this article, environmental boundary conditions, the chosen layout and the current status of civil construction is presented., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

LIPAc* will be a 9 MeV, 125 mA CW deuteron accelerator which aims to validate the technology to be used as neutron source of the IFMIF facility. Those facilities are essential for future fusion reactors material research. A 175 MHz RFQ will increase the energy up to 5 MeV before a Superconducting RF (SRF) linac with eight 175 MHz Half Wave Resonators brings the particles up to the final energy of 9 MeV. Between both stages, a Medium Energy Beam Transport line (MEBT)** aims at transporting and matching the beam between the RFQ and the SRF linac. The transverse focusing of the beam is controlled by five quadrupole magnets with integrated steerers, grouped in one triplet and one doublet. Two buncher cavities handle the longitudinal dynamics. Two movable scraper systems are included to purify the beam optics coming out the RFQ and avoid losses in the SRF linac. In this contribution, checkout of the beamline and its ancillaries in Japan is reported. Tests carried out on the beamline prior to the MEBT beam commissioning are described, focusing in vacuum tests, magnets powering, buncher conditioning and scrapers movement., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

The 3 GeV Rapid Cycling Synchrotron (RCS) of the Japan Proton Accelerator Research Complex (J-PARC) provides more than 300 kW beam to the Material and Life Science Facility (MLF) and the Main Ring (MR). In such high intensity hadron accelerator, the lost protons that are a fraction of the beam less than 0.1 % cause many problems. Those particles bring about a serious radioactivation and a malfunction of the accelerator components. Therefore, we carried out the beam study to achieve high power beam operation. Moreover, we also maintain the accelerator components to keep a steady operation. We report present status of the J-PARC RCS., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

We present a nonlinear rapid-cycling synchrotron designed as a high-intensity replacement of the Fermilab Booster. The design incorporates integrable optics, an innovation in particle accelerator design that enables strong nonlinear focusing without generating parametric resonances. We use the Synergia space-charge tracking code to demonstrate the stability of a beam in this lattice with a space-charge tune-shift up to 0.4 and a rms momentum spread up to 0.4\%. We demonstrate the benefit of increased lattice periodicity., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

High energy X-ray computer tomography has wide application in industry, especially in quality control of complicated high-tech equipment. In many applications, higher spatial resolution is needed to discover smaller defects. Decreasing the spot size of the X-Ray source is a promising way to get higher spatial resolution. Rhodotron have been used to produce high power CW electron beam in hundreds of kilowatts level. In this paper, we propose to use an improved Rhodotron to generate high brightness electron beam with high average power. Beam dynamics study shows that when producing tens of kilowatts electron beam, the normalized RMS emittance can be lower than 10 μm, and the relative RMS energy spread can be lower than 0.2%. The beam can be focused to a spot size of about 100μm by using a series of quadruple, and converted to X-Ray by using a rotating target within several kilowatts beam power. Improved Rhodotron proposed in this paper is a good candidate of X-ray source for high resolution high energy industrial CT systems., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

In 2011 a working group has been started to study performance limitations due to Space Charge (SC) in the four LHC pre-accelerators, LEIR, PSB, PS & SPS, in view of the LHC Injector Upgrade (LIU) project. To this end external and in-house simulation tools have been benchmarked for the LIU study cases with the long-term goal of providing a full sequence of tested CERN Space Charge tools. It became clear that SC studies must be combined with trustworthy models of the machines, including linear and non-linear errors. In particular an effective s-dependent non-linear model is required. Recent studies indicate that also the low frequency ripple spectrum due to conventional power supplies might play an important role for the beam dynamics in presence of space charge in the pre-injectors., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

J-PARC is the multipurpose research institutes. 10 years have passed since the user operation started. We have been considering the upgrades for the future and the target beam powers for 3 GeV rapid cycling synchrotron (RCS) and 30GeV Main ring (MR) are 1.5MW and 1.3MW. To achieve a 1.5MW of RCS output beam power, increasing the number of Linac proton particles is necessary. For accelerating such higher beam current, the rf systems in the RCS need to upgrade an accelerating voltage and to take account of heavier beam loading. In case of the MR, increasing the number of proton is not appropriate from the viewpoint of space charge effects. We chose to shorten the MR cycle time. The required RF voltages become almost double. All nine systems have been replaced with the higher accelerating gradient RF systems using a newly developed magnetic alloy material. At present, the proton beam of 470kW is being delivered with a cycle time of 2.48s. Beam powers of MR will plan to aim first at 750KW after replacing the magnet power supplies. But, to realize a 1.3MW beam power, upgrading the RF power sources will be necessary. We present the ring RF system status and their upgrades for the future., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

The J-PARC main ring (MR) provides 30 GeV high intensity beams for neutrino experimental facility (NU) by fast extraction and hadron experimental facility (HD) by slow extraction. It is a serious issue to ensure sufficient integrated proton number on target (POT) for each facility. A stretcher ring (ST) can solve this serious problem. A beam accelerated by the MR is transferred to the ST and is slowly extracted over several second. While the beam is slowly extracted in the ST, the MR can accelerate and deliver a beam to the NU. The ST is put above the MR and fitted in the MR tunnel. Arc sections in the ST consist of superconducting combined function magnets (dipole, quadrupole and sextupole components), and separated function quadruple and sextupole magnets (hybrid lattice). A 30 GeV beam transfer line (BT) from the MR to the ST uses superconducting combined magnets with dipole and quadrupole functions to shorten the BT. The transferred beam is injected into an arc section in the ST. The adoption of the superconducting magnets in the ST and the BT saves operation cost drastically. Beam optics designs for the ST and the BT will be described in this paper., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

In 2017, the LEIR accelerator has been operated with Xe³⁹⁺ beam for fixed target experiments in the SPS North Area. The different ion species, with respect to the usually operated Pb⁵⁴⁺, allowed for additional comparative measurements of tune shift versus intensity at injection energy both in coasting and bunched beams. The fast transverse instability observed for high accumulated intensities has been as well characterized and additional observations relevant to impedance have been collected from longitudinal Schottky signal and BTF measurements. The results of these measurements are summarised and compared to the currently developed machine impedance model., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

Longitudinal coupled-bunch instabilities after transition crossing and at the flat-top limit the intensity of LHC-type beams in the CERN Proton Synchrotron (PS). A dedicated coupled-bunch feedback for dipole oscillation modes, using a Finemet cavity as wide-band longitudinal kicker, suppresses the instabilities up to an intensity of about 2·10¹¹ particles per bunch at extraction. However, dipole and quadrupole coupled-bunch oscillations are observed beyond this intensity. At the flat-top they were damped with a 40 MHz RF cavity operated as a higher-harmonic RF system to increase Landau damping, in addition to the principal RF system at 10 MHz. The existing 40 MHz RF system, designed for RF manipulations at fixed frequency, does not cover the frequency range required during acceleration. It is therefore proposed to install a tunable RF system with a 5% relative frequency swing. This paper summarizes the observations of instability damping at the flat-top and presents preliminary parameters for the higher-harmonic RF system., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

The concept of recirculating superconducting proton linac was recently proposed. Beam dynamics simulations were carried out in a double-pass recirculating proton linac using a single bunch. Although all the beam line elements should be installed following the designed values, in reality, there exist machine imperfections that will cause beam off-centering and even particle losses. In this paper, we report on the study of the static and dynamic errors from RF cavities and magnetic focusing elements in the double-pass recirculating proton linac., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

The J-PARC RCS employes Magnetic Alloy (MA) loaded cavities and rf power is fed by vacuum tubes in push-pull operation. The multi-harmonic rf driving and the multi-harmonic beam loading compensation are realized due to the broadband characteristics of the MA. However, the push-pull operation has disadvantages in the multi-harmonics. An unbalance of the anode voltage swing remarkably appears at very high intensity beam acceleration. In order to avoid the unbalance, a single-ended MA cavity is considered for the RCS beam power upgrade because no unbalance arises intrinsically. We will describe the conceptual design of the single-end MA cavity for the RCS upgrade., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

The CERN SPS (Super Proton Synchrotron) serves as LHC injector and provides beam for the North Area fixed target experiments. Since the 2016 run automated local aperture scans have been performed with the main focus on the vertical plane where limitations typically arise due to the flat vacuum chambers in most SPS elements. For LHC beams the aperture limitations with the present low integer tune optics also occur at locations with large dispersion. Aperture measurements in the horizontal plane using a variety of techniques were performed and showed surprising results, which could partially explain the unexpected losses of high intensity LHC beams at the SPS flat bottom. In this paper, reference measurements from 2016 are compared with the ones taken at the beginning of the run in 2017. Several aperture restrictions in the vertical plane could be found and cured, and a potential systematic restriction in the horizontal plane has been identified. The results of the measurements and the origin of the restrictions are presented in this paper, and the outlook for partial mitigation is discussed., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

The Beam Breakup Instability is a critical effect to reduce in high current induction accelerators. The RF modes generated inside the induction cells can deflect or degrade subsequent beam traversing the cell. Significant effort has been invested in minimizing the effect over several decades. One mechanism that is known to reduce the transverse impedance, the main observable experimentally which directly relates to the BBU amplitude, is to introduce ferrites to absorb the fields. Another, less investigated mechanism, is to disturb the modes symmetry by inserting the drive rods at the proper locations in the cell. This paper will show that the drive rods can dramatically reduce the transverse impedance, and will show that simulations are maturing towards predicting this effect. Lawrence Livermore National Laboratory is operated by Lawrence Livermore National Security, LLC, for the U.S. Department of Energy, National Nuclear Security Administration under Contract DE-AC52-07NA27344., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

Future high current proton accelerators will need to minimize beam loss due to space-charge in order to achieve safe operation while achieving the desired physics goals. One method of space-charge compensation to be tested at the Integrable Optics Test Accelerator (IOTA) at Fermilab is the Electron Column. The concept for this device is to allow a circulating beam to ionize a small region of relatively high pressure residual gas, while using electric and magnetic fields to confine and shape the resulting plasma electrons. If the profile of the electrons is matched to the beam profile transversely and longitudinally, the electrons should counteract the space-charge force of the proton beam. Simulations of the IOTA proton beam circulating through the Electron Column have been performed, with the evolution of the electron plasma and its effect on the beam studied., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

The Warm Front End (WFE) of the Proton Improvement Plan II Injector Test [1] at Fermilab has been constructed to its full length. It includes a 15-mA DC, 30-keV H⁻ ion source, a 2 m-long Low Energy Beam Transport (LEBT) with a switching dipole magnet, a 2.1 MeV CW RFQ, followed by a Medium Energy Beam Transport (MEBT) with various diagnostics and a dump. This report presents the commissioning status, focusing on beam measurements in the MEBT. In particular, a beam with the parameters required for injection into the Booster (5 mA, 0.55 ms macro-pulse at 20 Hz) was transported through the WFE., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

The recirculating superconducting proton linac that has a potential to substantially save accelerator cost was re-cently proposed. It consists of three sections to accelerate the continues-wave (CW) beam to multiple GeVs. In the first section, the beam passes the linac two times. In the second and third sections, the beam goes through the linac four and six times. A phase-shifter is needed to meet the synchronous acceleration condition for multi-pass accel-eration using the same RF cavity due to the phase slip-page of the proton beam. Here we present the design of a variable field rectangular bend phase-shifter in which the beam goes to a different path in each pass inside the mag-net to meet the synchronous condition., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

After two-year's shutdown, the GSI accelerators plus the latest addition of storage ring CRYRING, will be back into operation in 2018 as the FAIR phase 0 with the goal to fulfill the needs of scientific community and the FAIR accelerators and detector development. Even though GSI has been well known for its operation of a variety of ion beams ranging from proton up to uranium for multi research areas such as nuclear physics, astrophysics, biophysics, material science, the upcoming beam time faces a number of challenges in re-commissioning its existing circular accelerators with brand new control system and upgrade of beam instrumentations, as well as in rising failures of dated components and systems. The cycling synchrotron SIS18 has been undergoing a set of upgrade measures for fulfilling future FAIR operation, among which many measures will also be commissioned during the upcoming beam time. This paper presents the highlights of the challenges such as re-establishing the high intensity heavy ion operation as well as parallel operation mode for serving multi users. The status of preparation including commissioning results will also be reported., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

The NSC KIPT SCA Neutron Source uses 100 MeV/ 100 kW electron linear accelerator as a driver for the generation of the initial neutrons. The trial operation of the accelerator was started in 2018. To provide design electron beam parameters is the primary task of the first stage of the trial operation. During the first stage of the accelerator operation the following tasks were under consideration: minimization of the electron beam losses along accelerator, providing of the stable electron beam pulse current, adjustment of the electron beam position along accelerator and providing of the uniform electron beam distribution at the tungsten neutron generating target. The main results of the accelerator operation and methods of performance improve are described in the paper., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

The J-PARC is a high intensity proton facility and the accelerator consists of a 400 MeV linac, a 3 GeV Rapid Cycling Synchrotron (RCS) and a 30 GeV Main Ring Synchrotron (MR). Regarding 3 GeV beam from the RCS, we delivered it at 150 kW to the materials and life science experimental facility (MLF), for the neutron and muon users. The beam powers for the neutrino experiment at 30 GeV was 420 kW in May 2016, but increased to 470 kW in February 2017 thanks to the change and optimization of operation parameters. For the hadron experimental facility which uses a slow beam extraction mode at 30 GeV, we delivered beam at a power of 37 kW, after the recovery from a trouble at an electro static septum. We have experienced many failures and troubles to impede full potential and high availability. In this report, operational performance and status of the J-PARC accelerators are presented., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

J-PARC 3-GeV RCS (rapid cycling synchrotron) provides a high-power beam both to MLF (materials and life science experimental facility) and MR (main ring synchrotron) by switching the beam destination pulse by pulse. The beam properties required from MLF and MR are different; MLF needs a wide-emittance beam with less charge density, while MR requires a low-emittance beam with less beam halo. To meet the antithetic requirements while keeping beam loss at permissible levels, RCS has recently initiated pulse-by-pulse switching of operational parameters (betatron tune, chromaticity, painting emittance, etc.). This paper presents the recent efforts toward the performance upgrade of RCS while discussing the related beam dynamics issues., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada

The Super Proton Synchrotron (SPS) beam dump system is a concern for the planned High Luminosity LHC (HL-LHC) operation. The system has initially been designed for very different beam parameters compared to those which will reign after the completion of the LHC injectors upgrade, when the SPS will have to operate with unprecedented beam brightness. This paper describes the relevant operational and failure modes of the dump system together with the expected beam loading levels. Tracking studies are presented, considering both normal operation and failure scenarios, with particular attention on the location and level of proton losses. First FLUKA investigations and thermo-mechanical analysis of the high-energy absorber block are described, Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

This paper surveys the key technologies and design challenges that form a basis for the next generation of very high intensity hadron accelerators, including projects operating, under construction, and under design for science and applications at MW beam power level., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

The prospects for future high-power proton beams for producing neutrinos at CERN within the LAGUNA-LBNO study, include the design of a 2 MW High-Power Pro- ton Synchrotron (HP-PS). In this paper, the optics design of the ring is reviewed, comprising Negative Momentum Compaction (NMC) arc cells and quadrupole triplet long straight sections, flexible enough to achieve the constraints imposed mainly by different beam transfer equipment and processes. A global tunability study is undertaken includ- ing aperture and magnet parameter considerations. Basic correction systems are specified and their impact to beam dynamics including dynamic aperture is finally evaluated., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

The well-known 3-gradient method allows accessing to a beam RMS emittance and Twiss parameters at a position A by measuring its rms size at a downstream position B with at least 3 different transport conditions from A to B. We suggest extending this method to access to a beam phase-space distribution model at A from beam profiles measured at B. We propose to use an iterative method which consists in: - defining a parametric model describing the beam distribution in 4D transverse phase-space at a position A, - adjusting iteratively the model parameters by minimizing the difference between beam profiles measured at B and these obtained by transporting the beam generated according to the model with TraceWIN code from A to B. This method allows taking into account space-charge and other transport non-linearities., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

The construction of IPHI (High Power Proton Accelerator) is in its final step of installation. The RFQ will accelerate beam up to 100 mA with energy up to 3 MeV. The RFQ, made of six modules, one meter each, is of the four-vane type. The RFQ is divided in 2-meter long segments with capacitive coupling. It is also equipped with 96 fixed tuners and four waveguide RF ports located in the fourth module. This paper describes the procedure used to tune the accelerating field and power couplers of the RFQ., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

The accelerator for RISP, which is the superconducting technology based heavy ion linear accelerator construction project, is composed mainly of the driver linac for stable ion beam from an ECR ion source and post linac for unstable ion from an ISOL system. The post accelerator can accelerate the unstable ion beams up to 16.5 MeV/u for 132Sn and 16.0 MeV/u for 58Ni, which has the ratio of mass to charge, A/q, of 8.3. The unstable ion beam such as 132Sn from an ISOL system has the large transverse and longitudinal emittances. Hence acceptance and envelope of the post accelerator should optimize for stable operation. The beam was transported by the post-to-driver transport (P2DT) line which consists of a charge stripper, two charge selection sections and a telescope section with the bunching cavities. In this presentation, we will show the criteria for the design of the post accelerator and result of beam tracking simulation from the low energy transport line to the end of post linac. The initial coordinates of the particles were acquired by the tracking simulation from the low energy beam transport (LEBT) line to the medium energy beam transport (MEBT) line., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

The FNAL Proton Source is currently undergoing a major improvement effort. A plan has been developed and is underway to increase Proton Source throughput while maintaining good availability and acceptable residual activation. The plan addresses hardware modifications to increase repetition rate and improve beam loss while ensuring viable operation of the proton source through 2025. The PIP goals will enable Linac/Booster to: Deliver 2.25·10¹⁷ protons per hour with a 15 HZ cycle rate Availability greater than 85% Maintain residual activation at acceptable levels. The work has been progressing on schedule and is expected to finished by 2018., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

Big issue for the J-PARC 3GeV RCS was displacement of main magnets caused by last big earthquake because this made beam loss more than 400 kW beam power. Since realignment of main magnet and other components was essential to realize higher beam power and stable operation, this work has been done last maintenance period. To minimize amount of realignment work, we decided that not all components moved to designed regular potions but also minimum components moved to the position which was secured design acceptance 486 π mm mrad. Almost all components which are main magnets, rf cavities, and extraction magnets had to be moved in the range of 10 mm for horizontal, 3 mm for vertical and 9 mm for longitudinal, respectively. It was not necessary for the components installed in injection straight line to move because displacement of these components was less than ± 0.2 mm. At same time 400 MeV injection upgrade work should be done. Beam commissioning is planned from the middle of January 2014. The progress and status of the RCS in J-PARC are presented., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

In the framework of the LHC Injectors Upgrade project (LIU), a complete replacement of the existing narrow-band rf systems of CERN PSB with wide-band magnetic alloy (MA) loaded rf systems is in progress. A single gap MA loaded rf system prototype, which uses solid-state power amplifier and includes fast rf feedback for beam loading compensation, has been installed in the J-PARC MR to investigate the system behavior with high intensity proton beams. We report the wake voltage measurement results with and without fast rf feedback. In addition to the fast feedback, the rf feedforward method is under consideration to compensate the heavy beam loading more effectively. Preliminary beam test results with feedforward are also presented., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

Last summer shutdown J-PARC RCS injection energy was upgraded from 181 MeV to 400 MeV. We report the effect of the injection energy upgrade on the residual dose in the RCS., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

The Front End Test Stand (FETS) at the Rutherford Appleton Laboratory (RAL) is intended to demonstrate the early stages of acceleration (0-3 MeV) and beam chopping required for high power proton accelerators, including proton drivers for pulsed neutron spallation sources and neutrino factories. A Low Energy Beam Transport (LEBT), consisting of three solenoids and four drift sections, is used to transport the H⁻ beam from the ion source to the Radio Frequency Quadrupole (RFQ). We present the current performance of the LEBT with regards to beam alignment, transmission and focusing into the acceptance of the RFQ., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

To ensure safe functionality and reduce unneccessary shutdowns, a risk analysis of the main driver accelerator for the FAIR project SIS100, has been done. The analysis includes all major technical systems and was done accordingly to EN 61508. Results of the analysis and appropriate countermeasures for detection and/or mitigation of the failures are presented. Furthermore, an estimation of the accelerator‘s availability is given., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

The high intensity proton accelerator complex (J-PARC) consists of the Linac, the 25Hz rapid cycling synchrotron (RCS) and the 50GeV main synchrotron (MR). During the long shutdown of 2013, the Linac energy was upgraded from 181MeV to the design value of 400MeV. In the RCS, we have installed the last 12th RF system. In operation from January 2014, beam commissioning aimed at 1 MW operation will be started. In the MR, the upgrade plan of the beam power, realizing by raising the repetition, has been started. For this reason the accelerating voltage must be increased, and all MR RF systems will be replaced with more efficient systems. A new magnetic alloy material (FT3L) has been developed. Manufacturing of the FT3L accelerating cavities has proceeded. It becomes possible to increase the accelerating voltage from 280 kV to 540 kV, using the new cavities in combination with the existing RF power supplies. We have started the developments of a 2nd harmonic system loaded with air-cooled FT3L cores and a high-Q VHF cavity system, too. Both systems are used for longitudinal dilution increase the bunching factor of the circulating high intensity proton beam., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

The Frankfurt neutron source at the Stern-Gerlach-Zentrum (FRANZ) will provide ultra-short neutron pulses at high intensities and repetition rates. The neutrons will be produced using the 7Li(p, n)7Be reaction induced by a proton beam. The 175 MHz IH-type drift tube linac with 8 gaps succeeds a 4-rod-RFQ. Together they form a coupled linac combination with a length of 2.3 m and accelerate the protons from 120 keV to 2.03 MeV. As the RF losses add up to 200 kW, the cooling of both accelerators is a central challenge. The RFQ-IH combination is powered by a radio frequency amplifier, which couples the RF power into the RFQ. The two structures are connected via inductive coupling. The initial beam operation of the accelerators is configured for 50 mA in cw mode. The IH-components were fabricated, RF tuning measurements are underway. The RFQ and the IH-DTL will be conditioned separately and then be connected, aiming for a beam operation at the end of 2014. A main challenge in fabrication was the precise welding required for the water cooled drift tubes and stems., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

A high-harmonic RF system that could serve multiple purposes was proposed for the LHC. Possible applications of the second harmonic RF system include beam stabilisation in the longitudinal plane in the absence of wide-band longitudinal feedback and reduction of bunch peak line-density. Apart from other useful features, flat bunches are expected to produce less beam-induced heating at frequencies below 1 GHz, the frequency region critical for some LHC equipment. The latter, however, can also be achieved by de-populating the bunch centre. This was demonstrated during the dedicated machine development session in the LHC using RF phase modulation. In this paper the results of tests with single bunches and nominal LHC beams are presented and the possible use of this technique in LHC operation is discussed., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

In J-PARC, a radioactive material leak accident occurred at the Hadron Experimental Facility on May 23, 2013. The accident was triggered by a malfunction of the slow extraction system of the Main Ring synchrotron. After seven-month long shutdown due to the accident, beam operation of the linac was restarted in December 2013. In this paper, the most recent status of the beam operation is presented., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

There are many interesting proposals and programs for accelerator driven subcritical facilities for waste transmutation(ADS) in the world, which is to speed up from the basic study to the real facility, and the significant progress in the development of accelerator technologies, in particular, superconducting RF linacs for ADS, but the key technologies in high power proton accelerator are still severe challenges which call for the closer international cooperation. This talk provides a broad overview of worldwide ADS accelerators., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

Intensity upgrade of very heavy ions such as uranium or xenon beams is one of the main concerns at the RIKEN Radioactive Isotope Beam Factory (RIBF). The lifetime problem of carbon-foil strippers due to the high energy loss of beams was a principal bottleneck for the intensity upgrade. We have already developed and successfully operated a re-circulating He-gas stripper for 10-MeV/u uranium beams as an alternative to carbon foils. Recently, the 2nd gas stripper with air dedicated for 50-MeV/u ¹²⁴Xe beams was developed. The differential pumping techniques similar to that used in the He gas stripper was applied. We confined a very thick gas target, up to 20~mg/cm² of air, in a 0.5-m target chamber. One good feature of using air is that it can be inexhaustible for our use. The stripper was stably operated in user runs performed in June 2013. The service rate reached 91\%. The maximum beam intensity reached 38~pnA and the average intensity provided to users becomes approximately four times higher than it was in 2012. The down-time free gas strippers greatly contributed to these improvements. We also discuss the applicability of the air stripper to 50-MeV/u ²³⁸U beams., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

The radiation leakage accident occurred at the J-PARC hadron experimental hall in May 2013 was triggered by a target damage due to an unanticipated short beam pulse from J-PARC main ring. An extremely short beam pulse was produced by a rapid current increase of the quadrupole (EQ) power supply system for a spill feedback. A simulation with the slow extraction process could explain such a short beam pulse generation. The cause of the malfunction has been identified by an intensive investigation of the EQ power supply system performed after the accident. We will show measures to prevent recurrence., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

CERN has put in place an ambitious improvement programme to make the injector chain of the LHC capable of supplying the high intensity and high brightness beams requested by the High-Luminosity LHC (HL-LHC) project. The LHC Injectors Upgrade (LIU) project comprises a new Linac (Linac4) as well as major upgrades and renovations of the PSB, PS and SPS synchrotrons. The heavy ion injector chain is also included, adding Linac3 and LEIR to the list of accelerators concerned. This paper reports on the work completed during the first long LHC shutdown, and outlines the further upgrade path., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

A new High-Power Proton Synchrotron (HP-PS) is being studied at CERN for the second phase of the Long Baseline Neutrino facility (LAGUNA-LBNO) where a 2 MW beam power shall impinge onto a target. A 4 GeV H⁻ injection based on foil stripping and extendable to laser-assisted magnet stripping is described. The proposed laser-assisted stripping is assessed with regard to the laser power requirements. The feasibility of a fast extraction system at 75 GeV is presented., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

J-PARC is currently upgrading their linac from 181MeV to 400 MEV with a new ACS section (annular coupled structure). This includes a triple frequency jump, and there should be some interesting results to report. As the result of the injector linac upgrade at J-PARC, the Rapid Cycle Synchrotron (RCS) will achieve a record-high intensity as a proton accelerator. This talk describes the recent performance of the RCS together with its beam-dynamical issues., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

Superconducting RF particle sources combine the advantages of normal conducting RF sources and high duty cycle non-RF sources. The Rossendorf SRF gun was the first to demonstrate this injecting electrons into the ELBE accelerator at 13 MHz. Recently, a new 3-1/2-gun cavity has been prepared at Jefferson Lab for its use in an updated injector which is expected to increase the electron energy from 2.4 to 7.5 MeV. Along with this new cavity, a new gun cryostat has been introduced. It combines several minor updates to the setup with the installation of a superconducting solenoid right at the exit of the gun, compensating the emittance growth of the electron bunch at an early stage. The poster is going to conclude the results of the commissioning of the new cryostat including the solenoid and compare it to the prior concept using a normal conducting solenoid outside the cryostat. As it is of great importance to this subject, studies of the magnetic shielding are going to be presented as well., Proceedings of the 5th Int. Particle Accelerator Conf., IPAC2014, Dresden, Germany

The MYRRHA project borne by SCK•CEN, the Belgian Nuclear Research Centre, aims at realizing a pre-industrial Accelerator Driven System (ADS) for exploring the transmutation of long lived nuclear waste. The linac for this ADS will be a High Power Proton Accelerator delivering 2.4 MW CW beam at 600 MeV. It has to satisfy stringent requirements for reliability and availability: a beam-MTBF of 250h is targeted. The reliability goal is pursued through a phased approach. During Phase 1, expected till 2024, the MYRRHA linac up to 100 MeV will be constructed. It will allow to evaluate the reliability potential of the 600 MeV linac. It will also feed a Proton Target Facility in which radioisotopes of interest will be collected through an ISOL system. This contribution will focus on the transition to integrated prototyping, which will emphasize (i) a test platform consisting of the initial section of the normal conducting injector (5.9 MeV), (ii) the realization of a complete cryomodule for the superconducting linac and of its cryogenic valve box. The cryomodule will house two 352 MHz single spoke cavities operated at 2K., Proceedings of the 9th Int. Particle Accelerator Conf., IPAC2018, Vancouver, BC, Canada