MUON piquet report 18/9 -24/9 2012

Nikolai Bondar

17/9- 21/9 TS week

Main task for TS1. HV chamber conditioning2. Replacement of faulty RDB#04 connected with M3C13C _GapB 3. Try to fix the hole in track map in Q4M4R2 _1, chs 130-131 -

M4C18A34. Increase LV on FEBs everywhere by 100-200 mV 5. Replace LV fuses for FEBs in M3CR16. Installation of a ferrite cable filters to suppress the noise on

chamber 7. Replacement O-rings in water cooling system

1. HV chamber conditioning

Tested 40 chambers, 160 gaps 150 gaps – OK 10 gaps have some problems See details at

https://lbtwiki.cern.ch/bin/view/MUON/TodoListNextTS

17/9- 21/9 TS week

2. Replacement of faulty RDB#04 connected with M3C13C _GapB

- Done

3. Try to fix the hole in track map in Q4M4R2 _1, chs 130-131 - M4C18A3 - Tested all connection from chamber to IB and from IB to ODE. No problems were found . 4 . Increase LV on FEBs everywhere by 100-200 mV - LV increased on C side everywhere and on A side only M23, R1, R2 Many chambers on R1, R2 and some on R3,R4 need to adjust threshold!

17/9- 21/9 TS week

5. Replace LV fuses for FEBs in M3CR1 Actually we only refreshed connections of the fuses by

re-plug the same fuse. It was done at C-side everywhere and at A-side only M23 R1,R2

Found 2 burned fuses.

6. Installation of a ferrite cable filters to suppress the noise on chamber.

Installed 22 filters on M5-back. All chambers absolutely quit. Waiting for beam to do more accurate test. Need order more filters!

17/9- 21/9 TS week

7. Replacement O-rings in water cooling system We had a water leak at A-side inside the rack two times during

month August - September period.

With expert assistance we understood that the hose joint to the rack cooling circuit was done not precisely correct.

Final decision – Reconnect two racks on A-side in accordance of all

recommendation Done Improve water leak sensors position to be more sensitive

Done Keep spare part for emergency in case of leak. Done

Two spare pieces are in the piping toolbox

17/9- 21/9 TS week

Two days were devoted to adjust threshold on the chambersThe thresholds were set by hand with an uncertain accuracy.

Needs threshold scan!

Found problems: Many chambers were without voltage stabilizers (input voltage

less than required). Expected reason – increased voltage drop in the fuse contacts.

Many chambers, in particular central regions, are calculating extra pulses during read out scales inside CARDIAC.

Expected reason – ground problem on the chambers.

22/9- 23/9 after TS week