1. E.Guschin (INR,Moscow) 12 February 2008PS/SPD commissioning meeting CERN PS/SPD LED monitoring system status Done: All final cabling, except rearrangement is needed on ‘A’ side around the rack checks on cables (resistance ( except SPD5-6 ), connections, delays) cut off the ‘dead’ LED (~10 channels) because of low resistance and current consumption problem checks with data PS1-4, but analysis is to be finished Missing: data (proposal to place all taken data related to LED scan in accessible space) ; new data is necessary because of: 1.Many works are done on cables and system after first data taken 2. it will also allows to check final connection of all LED system to the control units (limits of current, regimes of LED in group of 144, etc)

2. E.Guschin (INR,Moscow) 12 February 2008PS/SPD commissioning meeting CERN Known problems PS: –SM PS4 : needs tuning + access + data(~2 days) SPD: (list of Edu) Three type of problems: 1.Low signal in some LED - action: to be checked for ‘dead’ LED 2.No signal in group of 16 - to check cable connections 3.Large signal in some LED or large nonuniformity – needs check/tuning on the detector (access + data): –‘A’: SPD5 T1,T2,B6,B10; SPD6 T2,T4,T5,B3; SPD7 T1,T2,T4,B3,B5; SPD8 T2,B1 –‘C’: SPD3 T10; SPD4 T4,T6

3. E.Guschin (INR,Moscow) 12 February 2008PS/SPD commissioning meeting CERN To do To measure resistance on LED power cables (SPD 5 and 6) input from the platform Sergey: ‘ One thing left to do is to measure current consumption for bias line for SPD SMs 5 and 6. It was found some time ago that it is impossible to control LED signal due to broken LEDs that died with a resistance ~300 Ohm. We found and cut four LEDs for PS1: module P20, pin #7 and 11; P138: 11; P95: 15; P70: 10 and one for PS4 6i2: 1. I'm afraid I was confused with left/right pin numbering but missing LED lines can be easily seen on the connector and in the data’. To rearrange the LED cables on “A” side around the rack.

4. E.Guschin (INR,Moscow) 12 February 2008PS/SPD commissioning meeting CERN To do To (re)measure LED signals as function of LED bias (intensity) for PS ‘A’ and ‘C’ side in order to check LED operation for all detector regions connected (see attached mapping). To remeasure LED signals with threshold scan for SPD in order to check problems from Edu’s list. Some of the problems was resolved in summer. + to check again the mapping in SPD 2,7,8 in central part for trigger cable connection.

5. E.Guschin (INR,Moscow) 12 February 2008PS/SPD commissioning meeting CERN LED group mapping To be checked for swap of trigger cables 2 and 3 To be checked