1. 1 Drift Tubes TC activities up to LS2 1.Implement remaining Phase 1 upgrades :  in USC ⁻ TwinMux ⁻ microROS 2.Refurbish HV & LV Power Supply Systems ⁻ Largest CAEN based system  in both caverns 3.Repair Minicrates ⁻ Long access time in 6 gaps YE1|YB2|YB1|YB0|YB-1|YB-2|YE- 1 ⁻ Estimated Access time/resources: ~LS1 4.Prepare the chambers for the long run ⁻ Shielding of outer station MB4?  moderate crane use ⁻ Review cooling and gas flexibles 3/11/2015I. Redondo

2. 2 Phase 1 upgrade: TwinMux & µROS 3/11/2015 I. Redondo S1D row TwinMux microROS µROS board is TwinMux HW with different FW LS2 is latest possible installation time, ROS becomes bottleneck afterwards. FW integration well advance First exercise of DT+RPC superprimitives HW preproduction being tested First 9 boards in hand Slice test infrastructure installed DAQ link testing at P5  TwinMux Installation expected YETS15-16 Schedule depends on full L1 upgrade Fallback plans require (temporally) rack space, in S1C13,S1C14

3. 3 Power Supply System: mainframe replacement 3/11/2015I. Redondo Better do it in a longish period: Intervention requires commissioning of communication lines though long cables

4. 4 Power Supply System: A876 optocoupler exchange 3/11/2015I. Redondo

5. 5 More on Power Supply HV Power supplies are quite efficient collecting dust ⁻ seen failure rate decrease after dusting of some of the boards 3/11/2015I. Redondo

6. 6 Working in the Gaps: MiniCrate Maintenance & Chamber HV In the absence of surprises intervention in chambers will be limited to Phi SLs ⁻ no movement of chambers, no crane MiniCrates are DT on-detector digital electronics, providing ⁻ Trigger ⁻ TDC&Readout ⁻ Slow control for itself, for analogic frontend, alignment & RPC Its aging and radiation hardness is a concern: ⁻ We will replaced them in LS3. Cannot realistically do it in LS2 (or LS4.) ⁻ meanwhile its maintenance requires long access time 3/11/2015I. Redondo

7. 7 MiniCrates Repairs in LS1 40% of the MiniCrates were repaired ⁻ a large effort both in terms of manpower and access time ⁻ 3% DT (~5000 channels) recovered MiniCrates are complex systems with multiple failure modes ⁻ Most of them are mild, involving a small number of channels ⁻ CCB/SB/Splitter board can bring down a full chamber ⁻ Other chamber scale single point of failures for readout/trigger only exists (ROLink, SB) Concerning the aging of the system, the clock did not stop ticking at the end of run I ⁻ Actually the frequent power cycles during a shutdown brings more stress to the system than normal operating conditions radiation is not the dominant cause of failure so far. ⁻ 1.5 % of dead channels added during LS1 3/11/2015I. Redondo

8. 8 YETS16-17 d16-d68 https://indico.cern.ch/event/387806/contribution/42/2/material/slides/1.pdf 3/11/2015I. Redondo YB-2 YB+2 accessible for 50 days

9. 9 LS2: repair Minicrates in parallel with other tasks a là LS1 ~2.5 m wide gaps to insert a cherry picker in 12 positions,6 gaps (# MCs extrapolating from LS1, assuming YB+-2 repaired in YETS16-17): ⁻ YE1| YB2|YB1|YB0|YB-1|YB-2|YE-1 We prefer not to use scaffolding (stay nimble), but if installed for other tasks we could also use it as long as there is a gap (20-40 cm) to the face of the chamber. Work can progress as long as access to 1 of the 12 positions, easy to orchestrate with other interventions. For logistic reasons (experts trips) request to group access in >~O(1) week time. ⁻ YE1| 2w |YB2| 5 w|YB1| 4w |YB0| 4w |YB-1| 5w |YB-2| 2w |YE-1 3/11/2015I. Redondo 1010 # MC Repair DT MC/Chamber No scaffolding, No crane NB: this wide open barrel configuration is not needed, just pictorial view to indicate 12 access regions 1010 1010 1010 5 55 5 5 5 5 5

10. 10 A.Benvenuti G. Masetti light shielding has been installed in 2 worst chambers (MB4 S4 YB+-2) during LS1 Neutron spectrum in the cavern main uncertainty Note also new unknowns: 8  13 TeV & YE4 effect Effect of prototype shielding being evaluated If effective, completing the top sectors (3 chambers) is straight forward  YETS16-17? Extending the shield to other sectors requires further design  LS2 Concerns in the long term: Readout Inefficiency Chamber longevity Shleding top MB4s Massimo+Mimmom+Vincenzo +Sandro di Vincenzo&tem

11. 11 Tentative Schedule 3/11/2015I. Redondo Requires access/crane No access/crane May not be needed

12. 12 3/11/2015I. Redondo Operating on a MiniCrate is an extremely difficult task courtesy of Mimmo

13. Preparation for 2015 Board Replaced board YB-2YB-1YB0YB+1YB+2 TRB phi 771495 TRB theta 45 2 22 Link 456 1 CCB 2111 SB 11 ROBUS 1112 ROLINK 112 TRB flat 111 FE problems 12121 ROB 11 Splitter Board 1 Recovered channels 0.4%0.5%0.3%0.8%0.9% Minicrates intervention 2220 22 3 % DT(~5000 channels) recovered Minicrate Maintenance 3 chambers recovered in January. TC moved YB+2 to allow the intervention in YB+1 S11 MB3. LS1 : 40 % of the MCs were repaired Full chamber failures~O(1/2) chamber scale failures