Topics from this weeks 2E34 meeting

M. WeaverJan 6, 2006

January Goals

• Recover currents and luminosity– 1.5 A x 2.4 A– Fix vacuum leaks– Fix transverse feedback issues

• Recover L = 1E34– 1.75 A– 3.0 A– Fix fast LER instability

• Integrate – 15 fb-1 in January– 800 pb-1 in one day– Average 1E34 for week

J.Seeman

Status

• We have uncovered at least two problems

• A pressure rise in the HER at the boundary between straight 6 and arc 7– Started to rise Dec 22

• Vacuum spikes seen in IR2 very close to the detector– Starting time for these events less certain

M. Sullivan et. al

First pair of pumps in arc 79011 and 9012

Last pair of pumps in straight 68093 and 8103

M. Sullivan et. al

Late news (ink is still wet)

Leak in PR06 found and fixed with VacSeal

M. Sullivan et. al

Pressure spikes near the BaBar detector

M. Sullivan et. al

LER HER703930 nTorr

SIG11LER sensitive2600 (100 is high)

2187100 nTorr

3027 gauge and pump300 and 200 nTorr3044

? nTorr

LER frangible link

M. Sullivan et. al

Most likely candidate for this kind of pressure burst is an arc

Most likely suspect would be the frangible link but we have to get pump 3044 working…

Will try single ring again and have strip charts running to look for pressure spikes. BaBar in the off state can take much higher radiation levels.

Look into acoustic detectors?

Look into other ways of detecting an arc…

Summary of IR2 pressure bumps

M. Sullivan et.al

Implemented upstream anddownstream of the frangible link

on an abort-triggered oscilloscope

LER IR2 vacuum pumps VP3027, VP3044, and VP3050 added to the kHz abort data logger. VGCCs will be added later, but latency

may be a problem.

First abort showed that vacuum spikes followed increased background levelsby ~0.5 second but preceded the abort by 0.2 seconds.