| Paper | Title | Page |
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| WEAZ07 | Shock wave propagation near 7 TeV proton beam in LHC collimator materials | 241 |
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A study is presented to estimate the influence of the impact of a 7 TeV proton beam on the physical-mechanical material properties, such as C for collimators, and Cu elsewhere. The high energy stored in each bunch can produce a shock wave near the impacting proton beam in these materials. The theoretical model for the investigations of shock wave propagation in the collimator materials takes into account ionization, electronic excitation, and energy transfer from excited electronic subsystem in the materials to the ionic subsystem. The change of other physical properties of the material is also considered. The deposited energy is calculated with FLUKA [1]. The numerical results of the microstructure change in the material are presented for different numbers of bunches. The method allows investigating changes of density and internal pressure, the distributions of atomic and sound velocities, and the temperature profiles in electronic and ionic subsystems of materials near the front of shock wave. These results are very relevant for the understanding the behavior of collimator materials used in LHC under 7 TeV proton beam.
[1] A. Fasso et al. The physics models of FLUKA: status and recent development, CHEP 2003, LA Jolla, California, 2003 |
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| THBZ01 | Commissioning of the LHC collimation system | 0 |
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| The collimation system of the Large Hadron Collider (LHC) will rely on 90 collmators for beam cleaning and machine protection. The full system includes betatron and momentum cleaning collimators, beam absorbers, local protection elements, injection protection devices and transfer line collimators. These collimators must all be coherently adjusted with tight tolerances to small gaps around the beam, at distances from the beam centre that range from 4.5 to 10 betatron beam σs. In particular, the relative rectraction of elements placed in different locations along the 27~km LHC ring must be respected to ensure the required overall cleaning and protection performance. In this paper, the proposed scenarios for commissioning and operating this complex system are discussed. The achievements at SPS with a collimator prototype are also outlined. |