2011-08-02LHC 8:30 meeting EBH 1

Cryogenics recovery in point 8

Meanwhile a couple of accesses: MKI investigation on noise in IP2 Insulation Vacuum

One of the 3 turbo pumps pumping the known helium leak in sector 3-4 (subsector A27L4.M) had failed on Sunday ~13:15.

Monday: turbo pump replaced and vacuum pressure returned to the level prior to the failure.

Checking of UPS in UJ56 CMS Access system UJ43:

PAD1 still in “CLOSED” after mode changed to “RESTRICTED” MAD tunnel side door keeps opening fixed

Monday 1.8.2011

2011-08-02LHC 8:30 meeting EBH 2

BLM: test of the time response of the BLM SIS HV interlocks All responses are checked and values are as expected

(interlock delay of 10 seconds on all crates except IP3 and IP7 central crate which have 1 minute delay)

Some BLM tunnel cards will need a manual reset (tunnel access needed), it is not mandatory for operation. It will be done in the next days if possible.

Monday 1.8.2011

2011-08-02LHC 8:30 meeting EBH 3

The diagnostic scope (left in UA since Saturday afternoon) recoded some runt output trigger from MS3 G1 trigger unit these would not be expected to explain the erratics, but may explain the jitter.

Check G1, G2A, and G2B trigger cables to MS3 OK

Intervention MKI2 – Mike Barns

G1 yellowG2A, G2B blue and pink

2011-08-02LHC 8:30 meeting EBH 4

Ferrite installed on input triggers (G1, G2A and G2B triggers) to the thyratron trigger unit, of: Trigger Main 3 Trigger Dump 3 Trigger Main 4 Trigger Dump 4

Note: following above some further runt trigger outputs were seen on MS3 G1 up until 13:00hrs. Returning after lunch, no more runt triggers occurred......

Replaced the crate for G1 trigger units of M3, D3, M4 & D4

Intervention MKI2 – Mike Barns

2011-08-02LHC 8:30 meeting EBH 5

23:47 probe beam injected MKI IP2: vacuum pressure ~4E-9 before injection of last bunch train

and steep recovery

Bunch intensity 1.15E11 beam intensity 1.59e14 Tune increased by 0.002 on both beams and planes Atlas/CMS luminosity: 1.86 Hz/nb

Fill # 1997

2011-08-02LHC 8:30 meeting EBH 6

Lifetime

2011-08-02LHC 8:30 meeting EBH 7

Vacuum

2011-08-02LHC 8:30 meeting EBH 8

Bunch Intensity Losses – 30 min after collision

2011-08-02LHC 8:30 meeting EBH 9

Bunch Intensity Losses – 30 min after collision

2011-08-02LHC 8:30 meeting EBH 10

Bunch length B1 grows faster

2011-08-02LHC 8:30 meeting EBH 11

The lumi-leveling for LHCb is not easy this night: their data are drifting all alone and we had to change several times the direction of leveling and the magnitude of the steps.

4:25 beam dumped: cryo arc sector 1-2 Possible SEU in UJ16: communication lost with the valves and

cryo lost in a couple of minutes. The cryo piquet could reset remotely.

2:47 hours in stable beams and ~17 pb-1 delivered luminosity

6:22 probe beam injected