Impact of the A48 collimator on the Tevatron B0 dipoles

Nicolas, Ludovic Y. ; Mokhov, Nikolai V.

Fermi National Accelerator Laboratory

关键词: Protons;    Fermilab Tevatron;    43 Particle Accelerators;    36 Materials Science;    Collimators;   

DOI  :  10.2172/811925
RP-ID  :  FERMILAB-TM-2214
RP-ID  :  AC02-76CH03000
RP-ID  :  811925

美国|英语

来源: UNT Digital Library

【 摘 要 】

To protect the CDF detector components in an event of an abort kicker prefire (AKP) in the Tevatron, a new collimator is to be installed at the A48 location during the summer 2003 shutdown. Detailed calculations have shown that this 0.5-m long ''single L-shape'' steel collimator will intercept a bunch of protons when such an incident occurs, providing reliable protection of the CDF main detector at an AKP. It will also mitigate the backgrounds induced by elastic beam-gas interactions upstream of B0. Although the Roman Pot detectors downstream of the A48 collimator will see an increased background, the amount of radiation they will receive either resulting from beam halo interactions in the collimator or during an AKP will not damage their sensitive parts. Secondaries resulting from beam halo interactions with the A48 collimator do not noticeably affect the downstream dipoles. The case of an AKP is quite different. As opposed to halo hits in the ''single-L shape'' unit (around 10{sup 5} p/s), a bunch lost on A48 during an AKP represents more than 2 x 10{sup 11} protons ''instantaneously'' interacting with the collimator material. Although the collimator protects the downstream superconducting (SC) dipoles against a damage in such an event, secondaries generated in A48 create a significant radiation load on the dipoles which will most likely result in a quench of the first one. This effect is studied in detail in this note. Energy deposition in the B0 dipoles downstream of a new A48 collimator to be installed in the Tevatron this summer is calculated with the MARS14 code to evaluate the dipole's quench stability at an abort kicker prefire.