1 PAST ESTIMATIONS ON THE ROLE OF PASSIVE ABSORBERS Francesco Cerutti for the team 2012 June 4th

2012 June 4th F. Cerutti CWG#142 2 warm magnets and passive absorbers IR7 betatron cleaning IR3 combined cleaning considerations for IR3 momentum cleaning OUTLINE

2012 June 4th F. Cerutti CWG#142 3 IP7 TCP.D C B 6L7.B1 v h s s MBW MQW TCAPA beam 1

2012 June 4th F. Cerutti CWG#142 4 [M. Karppinen quoted by M. for the MQW IN IR7

2012 June 4th F. Cerutti CWG#142 5 IR7 BETATRON CLEANING F. for intermediate collimator settings BEAM PIPE HEATING beam 1 horizontal halo COIL DETERIORATION for lost protons per beam peak dose TCAPA B C with 3 passive absorbers per beam

2012 June 4th F. Cerutti CWG#142 6 IR7 BETATRON CLEANING actual layoutwith metallic collimator elementpeak [MGy] stat. err. [%] peak [MGy] stat. err. [%] MQWA.E5L MQWA.D5L SLAC prototype [L. Lari] with an additional metallic collimator for lost protons per beam at 7 TeV (beam 1 horizontal halo) F. Cerutti Conceptual Design Review Phase II Collimation April 2009

2012 June 4th F. Cerutti CWG#142 h v h v with 1 passive absorber per beam and additional vertical collimators 7 IR3 COMBINED CLEANING M. Mauri R2E Meeting July 17th 2008 for lost protons per beam at 7 TeV (beam 1 horizontal halo) beam 1

2012 June 4th F. Cerutti CWG#142 8 IR3 COMBINED CLEANING TCP. 6 MBW.C B A 6TCAPA MQWA.E D 5 TCAPC TCAPB MQWA.C5 IP3 TCSG. 5 v h v h with two additional passive absorbers per beam: L. Lari CERN-ATS (IPAC 2011) peak dose [MGy]no additional TCAPswith additional TCAPs element\beam energy7 TeV3.5 TeV7 TeV3.5 TeV MQWA.E5L MQWA.D5L MQWA.C5L for lost protons per beam (beam 1 vertical halo) high peak also on MQWA.E4R3, just downstream of a pair of (h-v) collimators

2012 June 4th F. Cerutti CWG#142 9 how many losses? [see Mike’s talk] Over 2011, the TCP BLM in P3 gives almost a factor of 2 difference between beam 1 and beam 2 Looking at the P3/P7 sharing, wrt to the first TCP BLM in P7 (vertical collimator quite doubtful assumption), one gets a factor of 3.5 for beam 1 and a factor of 1.15 for beam 2 FLUKA geometry of IR3 rapidly available, thanks to the new FLUKA Element DataBase and LineBuilder which loss maps? (and corresponding collimator settings) readings of passive dosimeters installed 4 months ago in the locations suggested on purpose (attached to the beam pipe and the MBW external coils, being not accessible the concerned internal MQW coils), are expected to provide during LS1 relevant data and related benchmarking opportunities IR3 MOMENTUM CLEANING [data kindly extracted by P. Mala and M. Calviani]

2012 June 4th F. Cerutti CWG# CONCLUSIONS Guessed peak dose values in the MQWA.E-C5 L3.B1/R3.B2 (and possibly MQWA.E4 R3.B1/L3.B2) are not reassuring Dedicated shower calculations for the standard IR3 momentum cleaning scenario were not performed, and can in principle – after clarifying loss maps and normalization assumptions - be launched (manpower shortage will be overcome by the autumn) Dedicated measurements have been put in place (with Pierre Thonet, Davide Tommasini, Julia Trummer) and dosimeter reading could be carried out at LS1 The activation of the area (see Stefan’s talk) challenges a late TCAP installation