CERN, Geneva
A new 450 GeV/c extraction kicker concept has been investigated for the SPS, based on open C-type kickers and a fast-bumper system. The beam is moved into the kicker gap only a few ms before extraction. The concept is illustrated in detail with the LSS4 extraction in the SPS very similar parameters and considerations apply to the other fast extraction system in LSS6. A similar concept could also be conceived for injection but is more difficult due to the larger beam size. The technical issues are presented and the potential impact on the machine impedance is discussed.
CERN, Geneva
A single-sided mobile diluter (TCDQ) and a horizontal secondary collimator(TCSG) are installed in the extraction region of the LHC to protect the downstream elements from damage in case of asynchronous beam dump. These collimators have to be precisely setup to shield the arc aperture at 450 GeV, the triplet apertures and the tungsten tertiary collimators (TCT) at the low-beta collision points. During the LHC beam commissioning, several machine protection tests were carried out to validate collimator setup and hierarchy at different beam energies and intensities. The outcomes of these measurements are presented in this paper together with the results of particle tracking simulations for asynchronous beam dump. These studies allowed to quantify the leakage expected from dump protection collimators to the downstream elements, and to validate the system performance towards higher beam intensity.
CERN, Geneva
The LHC transfer lines, injection and beam dump systems are equipped with a series of active and passive protection systems. These are designed to prevent as many failures as possible, for example through surveillance and interlocking, or to absorb any beam which is mis-kicked or mis-steered on passive absorbers. The commissioning, validation tests and performance of the different systems are described, and the implications for the protection of the LHC against different failures during beam transfer are discussed.
CERN, Geneva
The very demanding LHC beam parameters put very strict requirements on the beam quality along the SPS-to-LHC transfer. In particular, the budget for the emittance increase is very tight. During the LHC commissioning, the emittances have been measured in the SPS, the two SPS-to-LHC transfer lines and in the LHC. Preliminary results show the importance of a very well controlled beam steering in the transfer lines together with the need of a robust trajectory correction strategy in order to guarantee long-term reproducibility. Another source of emittance comes from the tilt mis¬match be¬tween the LHC and its trans¬fer lines which generates cou¬pling at in¬jec-tion into the LHC and in turn will contribute to emittance increase. Preliminary results are also discussed.
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.
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.
CERN, Geneva
HiRadMat is a new facility under construction at CERN that will provide the users with the possibility to investigate the behavior of materials when irradiated with pulsed high energy and high intensity beams extracted from the CERN SPS. The need for such a facility was raised by the LHC collimation project to bridge the gap in knowledge about the resistance of materials under impact with high energy protons. This talk will review the material parameters for which a deeper knowledge would be needed for extensive use in high energy accelerators, and the kind of test that can be conducted in HiRadMat to improve this knowledge. In particular we will discuss destructive testing, meaning test of materials beyond the limit of rupture or at phase change, and damage testing that should reveal changes in materials properties due to long term irradiation below the rupture limit. The facility could be used as well for calibration of radiation detectors like BLMs. The main difficulty connected with the test is how to observe material changes. Some preliminary ideas on on-line and post-irradiation tests will be outlined.