Shielding studies at TDIs Results from Rob Appleby – Studies made for P8 (LHCb) – Aimed to look at what shielding can improve Local LHC BLMs LHCb RICH and BCM signals

Geometry implemented in FLUKA

June-July FLUKA results (‘simple’ shield geometries)

Recent results (IPAC): calibration with measurement

More realistic shield geometry (1 m concrete, 0.1 m hole) Factor 2 maximum gain on triplet

To-do list (from July) Check BCM signals in simulation for shielded/unshielded - OK; Check effects on RICH for worst-case grazing (BG to chase Richard J) – in progress – needs interface to GEANT model of LHCb…; Start detailed shielding design with S.Weisz – to do; Check shielding does not compromise normal BLM functionality (with Annika) - OK; Decide strategy for TCLIB BLM (threshold, sunglasses?) – to do; Write up results in a note - include MKI flashover case – IPAC note sufficient?

Conclusions and status “Realistic” shielding might gain factor 2 in the triplet BLMs No gain for TCTVB BLMs (the problem ones) Improvement for RICH still to do (LHCb people – probably maximum factor 2 TDI losses come from uncaptured beam or satellites – presently not the main source of beam losses Shielding would maybe give us more margin for 25 ns operation – probably not too urgent Propose to continue with implementation studies for the local shielding downstream of the TDI, in parallel to other activities