Barrel Maintenance Scenario for LS1 MUON-IB CMS week 11 December 2012 A. Benvenuti (INFN Bologna)

LS1 Barrel Schedule 26-nov-12  In spite of long shutdown, access to inner wheels, YB0 YB±1 is rather short  Main challenge is the large number of activities with conflicting requirements especially in YB0

DT Upgrade: TRB replacement in Theta SuperLayers Outline of LS1 Activities Plan has evolved on the basis of: Difficulty of intervention in YB0 Accessibility considerations for repairs Better estimate of the TRBs mortality rate  New TRBs will be installed only in MB1 (and MB2) of YB±2  “Easy” operation in the absence of the Beam Pipe

 12 OF trunk cables UX-USC are required for each wheel Central cabling team of 4-5 people required for 3 days each wheel  Increased granularity of SC power distribution in UX racks requires re- arranging LVDS cables from MC 2 persons from central cabling teams needed for 2 days each rack Final crate cabling done by DT personnel  Rearrangement of USC racks S1D08-S1D07 and S1D15 to S1D13 for Trigger and Readout Crates  SC Relocation can be done only after completion of ordinary maintenance and TRB replacement in a given Wheel DT Upgrade: Sector Collector Relocation

Ordinary Maintenance: RPC: Electronics replacement: FEB, LV DB (13 Chambers Gas leak search HV connectors replacement DT: HV problems (14 chambers) MiniCrates repairs (~39 ) Alignment: MAB maintenance, upgrade Preventive maintenance: leak detection cables, outer MB4s shielding, gas leaks, check flexible pipes, quick connectors on thermal shields, additional Hall probes, … Interleaved with:  HO refurbishment in YB0, YB±1 and YB±2  Strips, Pixel, HB cables on YB0 and access inside Solenoid Outline of LS1 Activities Typically, 6 days/wheel

DT HV Phi DT HV Theta RPC Extract Problems in DT or RPC MC Repair No access to YB0, YB±1 since February 2009 YB±2 MC maintenance in YETS 2009 DT HV problems: 2 chambers lowered to the floor, 4 extracted, 8 in place Fixed from IP side “easy” Uncabling, extraction on YB Usually only moving cables

days (24 if EB cables are already removed) The schedule is very tight for standard maintenance: gas leaks, HV connectors, ….. Some contingency can be achieved during Tracker YB0± access from: 1)Removing EB LV cables 2) HO SiPm replacement trial run on YB0+ S06,S07 DT HV Phi DT HV Theta RPC Extract MC Repair  Many activities in a very short time, S04 is the most complex sector Time estimates based on DT/RPC HO parallel work assume priority access to 2 SL (+1 small) and 1 CP Crane usage required for mounting/removing the chamber extractor (2hours/ 1 h) and for removing/installing 2 chambers in S04 (2hours/2h)

Cradle positioned as for MB1S04 but Large MB4 shown YB0 MB1S04 is easy to remove/install: Cradle is mounted above MB1 and is removed after MB1 is posed on support table Cradle insertion with ~1m extension rails requires 3m clearance in front of table times cradle size 4m  Cradle insertion footprint 6m x 4m  HV intervention+ test footprint 3m x 3m required for 2-3 days Crane needed to configure the cradle for MB4 and to rotate it upside down

MB4S04 Main difficulty in attaching cradle to YB0 Requires working under suspended weight (cradle) but secured to the iron. 3m x 4m floor footprint  HV repair with chamber on cradle  2-3 days required including testing + contingency MB4 S04 Removal (YB0-)

MB1S04 Two separate problems: 1)HV Board disconnected in SL1 L4 giving a loss of 16 channels (67 cm) 2)Front End Board in SL3 giving a loss of 4 channels in all layers HVBs and FEBs are inside the gas volume MB4S04 There is a short since 23/08/2009 in a strip channel of SL1 L4, most probably in the HVB. Enrico Borsato mitigated the problem at the level of the JunctionBox  It is important to understand what happened

Crane required for handling support pieces, 2 hours for mounting 1hour for dismounting Special extractor for RPC interventions can be mounted without the crane MB3 S08 Maintenance in December 2008

YB0- Workflow

/09/13 – 03/10/13 09/10/13 – 21/11/ HO RBX YB-1 must be aligned with VacTank to allow easy access to chambers Access scaffolding must be removed during S04(most problematic) and S10 work, 3m clearance between YB-1,YB-2 to pull MB2 S04 Crane usage required for mounting/removing the chamber extractor (2hours/1 hour) 2-3 SL required at all times to allow parallel work, YB-2 HO RBX are on IP side. YB-2 DT HV repairs done from IP side  YB-1 MABs survey before closing YB-2, 5m clearance required

The CHALLENGE

2 Bundles / side 1 bundle = 4 vacuum insulated pipes. One pipe split in 3 sections Check 3D models with mock-up 8 weeks manufacturing  Bottleneck for YB0-  Blocks work on YB-1 PIXEL CO 2 Cooling Pipes

Summary Main concern is the large assortment of different activities on YB0, hopefully the number and scope has finally stabilized. Last chance to fix DT/RPC problems on YB0 until LS2 or beyond (and it will not be any easier) Parallel work requires adequate resources, manpower and tooling. We cannot duplicate the crane but there should be enough scissor lifts and cherry pickers to go around. Interference between Barrel and EndCap Muon is primarily with crane access. But it is limited to few instances and mostly for short (~2 hours) periods. In the present schedule, DAQ1 and TTC availability severely affects YB+2 commissioning and SC relocation due to the late start of the Barrel activities.

Additional Material

TRB replacement and MiniCrate maintenance are the main activities VacTank access scaffolding prevents the efficient plan envisioned. It should be removed during the work on S03-S05 and S09-S11 2 SL required all time to allow parallel work for DT-RPC standard maintenance Crane usage required for mounting/removing the chamber extractor (2hours/1 hour) 2-3 SL required all time to allow parallel work, YB-2 HO RBX are on IP side /10/13 – 14/11/13

 Major concern is the impact of YETS13 and the availability of needed infrastructure: gas, cooling, power, DAQ..)  Few DT/RPC problems to be fixed but  S10 EB, TRACKER LV cable removal is laborious  Position of additional cable trays to be checked ASAP  DT HV problems in YB+1 must be fixed from IP side  VacTank access scaffolding should be replaced for YB+1 MB3S04 HV repair 18/11/13 – 14/01/14 16/01/14 – 11/02/ HO RBX

/02/14 – 19/03/14 16/01/14 – 11/02/ HO RBX YB+1 must be aligned with VacTank to allow easy access to chambers Access scaffolding must be removed during S04, S10 work, it is a barrier for SL displacement N-F 2-3 SL required at all time to allow parallel work, YB+2 HO RBX are on IP side. YB+2 DT HV repairs, MB4S04, MB4S12, done from IP side  YB+1 MABs survey before closing YB+2, requires 5m clearance

TRB replacement and MiniCrates maintenance are the main activities VacTank access scaffolding prevents the efficient plan envisioned. It should be removed during the work on S03-S05 and S09-S11 2 SL required all time to allow parallel work for DT-RPC standard maintenance Crane usage required for mounting/removing the chamber extractor (2hours/1 hour) /02/14 – 19/03/14

YB0- HO-DT-RPC Work Flow Remove MABs Remove vacuum tank Thermal Shields Remove “Removable services”  Disconnect/remove RPC/DT cables and services as needed  HO upgrade interleaved with DT/RPC maintenance: 2 days of HO Priority access to a bi-sector 2 days of parasitic access  DT maintenance on YB-1 (IP side) Lifting platforms (2-3 SL and 1 CP) should be available at all times to allow working on both sides of YB0 or on YB-1 Intermittent crane usage for chambers handling  Final tests (several days) after intrusive interventions are completed (DT-RPC preventive maintenance in parallel) Mount vacuum tank Thermal Shields interleaved with “Removable Services” installation Install MABs and test connectivity Survey MABs (5m clearance in front of YB0)  YB-1 can be moved on vacuum tank

Additional cable trays can be installed with CMS closed. Before interventions, remove: MABs, 1-2 VacTank TS ECAL LV cables, cable trays RPC DT cables as needed  In YETS08-09 YB0 was open on Z± => efficient conditions  Many activities in LS1: HO, DT, RPC, Tracker  Coexistence => inefficiency  But we all have to work  Careful, realistic planning mandatory for success

Opportunity for: Tuning HO SiPm procedures on YB0+ S6, S7 Removing DT/RPC cables where needed Fix MC problems  As scaffolding design allows