BRAN: LS2-plans TREX 2019-04-17 M. Palm, E. Bravin, BE-BI-PM

Plans Remove 2 BRAN-A (ionization chambers) IP1: 1 pcs IP5: 1 pcs Install 2 Cherenkov-based BRAN monitors

Existing BRAN prototype Crane support Tested at IP1L Verified feasibility of fused silica as sufficiently radiation-hard Cherenkov media Main drawbacks: In case of bake-out or maintentance: entire monitor must be removed+reinstalled using crane From experience: final position of BRAN sometimes adjusted by hand. Small items easily fall into the TAN, causing detector to tilt Manual disconnection of all connectors (from TAN “wall side”) ⇒ Make the BRAN more “remote handling”-friendly. PMTs at top of each tube 2x8 connectors (bayonet) 2 x 1/2 day, 6-8 people. Per IP-side. 8 x Stainless steel tubes Climbing on TAN to be avoided during HL-LHC… Copper sheets (15 mm)

Modifications Split monitor into two parts Top: Bottom: Connectors: Top: removable PMT house Split monitor into two parts Top: PMT housing, attenuation filters, etc. Bottom: Fused silica rods. Copper spacers (absorption) Connectors: Use connector panels (non-latching connectors) Ensure minimal impact on bake-out procedure

New BRAN: draft Installed by crane (as today) Operational position Crane support (rigid) Installed by crane (as today) Manual connection of coax, HV and air on “wall side” PMT unit (green) can be removed Mates with connector panel on back side Remove PMT unit if needed Leave main part in TAN permanently (no active parts) PMT unit: removable Connector panels (non-latching) Handle/Robot grip Bake-out jackets (permanent) LEMO (mixed coax/HV) Combitac MCR

Feasibility & Open questions

Bake-out (1) Pull out PMT house (robot / manually) Bake-out position Connector panel not directly above TAN slot Pull out PMT house (robot / manually) Store temporarily in box below TAN Or in bunker? Insert dust cover for fused silica rods Other EDMS 891392: “Max height over TAN 28cm (20 cm space on the top when extracting)” Still valid? <28 cm Crane support Gap for bakeout jacket (cover TAN surface)

Bake-out (2) New concept ok with TE-VSC (discussed with Nicolas Zelko) Cover this part during bakeout New concept ok with TE-VSC (discussed with Nicolas Zelko) If needed, we can prevent heat loss during bakeout with custom- made “bake-out hat” to cover crane support To be verified: connector panel temperature during bake-out (Worst case: we can install a fan during bake-out to cool the connector panel)

Remote handling Robot handling of PMT-unit is feasible Pending Robot gripper compatibility for installing/removing PMT unit Two solutions for connector panels: Combitac: ~200 N to engage LEMO “all-in-one” connector (coax + HV): ~150 N to engage Max robot push force: ~130 N → Lever mechanism needed to fully engage connector panels Advantage Combitac: patch cable connectors (e.g. LEMO 00, LEMO Y) can be integrated directly in connector panel. Robot handling of PMT-unit is feasible Lifting PMT-unit ok (few kg) Pull-push to engage/disengage connectors ok Add guide rails/support plate to facilitate insertion of PMT unit

Integration: IP1 Seems feasible TAN IP1 Left Integration: IP1 Seems feasible HL-LHC: Alignment cable on tunnel side of TAN will be installed (space reserved) → Avoid cables on this side. HL-LHC: space reserved for alignment. IP1 Left: View from wall side

Integration: IP5 (1) More difficult Crane BRAN-A

BRAN connector panel should not collide with this Integration: IP5 (2)

Summary, open questions Any preferences on which BRAN-A to replace at IP1 & IP5: Left or right? If not, we will keep the BRAN-As with best signal Bakeout Connector temperature during bakeout? [N. Zelko: worst case: use a fan to cool connector during bakeout] Can we temporarily store PMT housing below TAN/TAXN during bakeout? Robot PMT housing: ~5 kg weight not a problem Grip to be defined Push/pull force not enough to engage connector panels. Lever needed. Integration Max height of BRAN if left in TAB durin bake-out: 28 cm Still valid? IP5 crane compatibility Space restrictions RP Crane support remains above TAN surface during bake-out procedure. Any issues? …anything else that we missed?