JAEA/J-PARC, Tokai-Mura, Naka-Gun, Ibaraki-Ken
The Japan Proton Accelerator Research Complex (J-PARC) consists of a 400 MeV linac (181 MeV at present), a 3 GeV rapid cycling synchrotron (RCS), a 50 GeV (30 GeV at present) main ring (MR) and several experimental facilities. At present the entire accelerator complex is in the operational stage and delivering relatively a high power beam to all experimental facilities. There are two stages of injection and extraction in the entire complex. The RCS utilizes charge-exchange H- painting injection scheme, then accelerate beam up to 3 GeV and is simultaneously extracted for the Material and Life science Facility (MLF) and for the MR injection. Starting with a 3GeV injection, the MR accelerates beam up to 30 GeV and delivered either to the neutrino experimental facility or to the hadron experimental facility through corresponding extraction channel. In order to have a high quality beam, there are many challenges in each accelerator especially, with injection and extraction systems and becomes significant towards achieving higher beam power. The operational experience from all aspect with J-PARC injection and extraction systems will be presented.
CERN, Geneva
Linac4 will replace the currently used Linac2 in the LHC injector chain. The motivation is to increase the proton flux available for the CERN accelerator complex and eventually achieve the LHC ultimate luminosity goals. Linac4 will inject 160MeV H- ions into the four existing rings of the PS Booster (PSB). A new charge-exchange multi turn injection scheme will be put into operation and require a substantial upgrade of the injection regions. Four kicker magnets (KSW) will be used to accomplish transverse phase space painting in order to match the injected beams to the required emittances. This paper presents hardware issues and related beam dynamics studies for several painting schemes. Results of optimization studies of the injection process for different beam characteristics and scenarios are discussed.
ORNL, Oak Ridge, Tennessee
ORNL RAD, Oak Ridge, Tennessee
LANL, Los Alamos, New Mexico
BNL, Upton, Long Island, New York
The Spallation Neutron Source comprises a 1 GeV, 1.4 MW linear accelerator followed by an accumulator ring and a liquid mercury target. To manage the beam loss caused by the H0 excited states created during the H− charge exchange injection into the accumulator ring, the stripper foil is located inside one of the chicane dipoles. This has some interesting consequences that were not fully appreciated until the beam power reached about 840 kW. One consequence was sudden failure of the stripper foil system due to convoy electrons stripped from the incoming H− beam, which circled around to strike the foil bracket and cause bracket failure. Another consequence is that convoy electrons can reflect back up from the electron catcher and contribute to foil and bracket failure. An additional contributor to foil system failure is vacuum breakdown due to the charge developed on the foil by secondary electron emission. In this paper we will detail these and other interesting failure mechanisms, and describe the improvements we have made to mitigate them.
ORNL RAD, Oak Ridge, Tennessee
Advancements in laser technology have dramatically expanded the applications of lasers to particle accelerators. Today, lasers have been used for accelerators in a broad range from operational systems such as nonintrusive particle beam diagnostics instruments and photoinjectors, to elaborate applications with high technical readiness levels including, for instance, a laser assisted foil-less charge exchange injection scheme and laser-electron Compton scattering-based light sources, and finally to exotic topics such as laser driven electron/ion accelerators. This talk reviews recent experimental results achieved in the above applications, their requirements on laser parameters and challenges that require future laser technology development. Important technical elements including femto-second pulse generation, burst-mode optical amplifiers, beam stacking from laser arrays, and power enhancement optical cavity will be briefly described. The laser optics development for the laser wire beam profile monitors and the laser stripping experiment at SNS will also be introduced as application examples.
CERN, Geneva
The increase of the extraction energy of the CERN PSB to 2 GeV has been suggested as a method to increase the intensity of the LHC beam which can be obtained from the present injector complex. Such a change would require a redesign of the present PS proton injection system, which is already operating close to its limits within tight space constraints. The feasibility of a 2 GeV proton injection is discussed and a potential solution outlined. The implications on the injection equipment and on the performance in terms of beam parameters and losses are discussed.