IR 2 Vacuum Update M. Sullivan for PEP-II team For the 2e34 meeting of Feb. 15, 2006.
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Transcript of IR 2 Vacuum Update M. Sullivan for PEP-II team For the 2e34 meeting of Feb. 15, 2006.
Typical event from Feb 5th
LER HER
2.29
1364
122
LER frangible link
Detector
0
2.25
993
Support tube end bellows
NEG pump
Backward Q2 NEG
Forward Q2 NEG
0 0.08
Another typical event from Feb 5th
LER HER
0.54
1653
27
LER frangible link
Detector
0
0.82
198
Support tube end bellows
NEG pump
Backward Q2 NEG
Forward Q2 NEG
0 0.07
Small numbers have larger baseline subtraction errors
Vacuum events with single ring LER on Sat. morning Feb 11th
Vacuum spike
Big vacuum spike
100 nTorr squirt
Vacuum spike event at 11:50 on Feb 11th
2300 mA in LER only
LER HER
2.44
7950
16.9
LER frangible link
Detector
0.34
4.32
1413
Support tube end bellows
NEG pump
Backward Q2 NEG
Forward Q2 NEG
0 0.60
Squirt event at 11:51
LER HER
0
334
0.29
LER frangible link
Detector
0
0
1171
Support tube end bellows
NEG pump
Backward Q2 NEG
Forward Q2 NEG
0 0.07
The highest vacuum spike event at 11:57 on Feb 11th
2446 mA in LER only
LER HER
17.2
3830
225
LER frangible link
Detector
1.16
9.2
3672
Support tube end bellows
NEG pump
Backward Q2 NEG
Forward Q2 NEG
0 2.05
Big air event when we opened a valve
LER HER
240
0
3440
14
LER frangible link
Detector
24
81
1360000
Support tube end bellows
479
NEG pump
Backward Q2 NEG
Forward Q2 NEG
10000 nTorr squirt (no beam)
LER HER
1.01
0
10.1
LER frangible link
Detector
0.19
0.61
9125
Support tube end bellows
NEG pump
Backward Q2 NEG
Forward Q2 NEG
0.07 1.57
Argues that the 3027 gauge sees too much pressure
10000 nTorr squirt (with beam)
LER HER
1.01
0
10.3
LER frangible link
Detector
0.19
0.61
8720
Support tube end bellows
NEG pump
Backward Q2 NEG
Forward Q2 NEG
0.95 1.29
Argues that the 3027 gauge sees too much pressure
Forward Q2 NEG heating with beam
LER HER
0.38
72
5.1
LER frangible link
Detector
0.08
8.9
60
Support tube end bellows
NEG pump
Backward Q2 NEG
Forward Q2 NEG
0 0
The 8020 pump sees too much pressure
Heating up the forward Q2 NEG
Luminosity went down when we added gas.
The decrease is noticeable at a pressure of about 30 nTorr
Traced to the HER vertical spot size increasing.
Luminosity restored as the pressure goes down.
Heating up HER Q5 NEG (8020) on the forward side of the detector
Detector backgrounds remain low
380 nTorr
Heating of 8020 NEG today -- Feb 15th
LER HER
0.42
56
2.1
LER frangible link
Detector
0
380
20.6
Support tube end bellows
NEG pump
Backward Q2 NEG
Forward Q2 NEG
0 0.29
HER 8020 NEG
• When we heated up the HER forward side NEG (8020) we saw the HER vertical spot size increase and the lumi decrease when the gas pressure got up to about 30 nTorr
• The gas is predominately H2
• As the gas pressure increased further the HER vertical spot size got smaller again and the HER went horizontally unstable
• We lost the beams on a radiation abort, however there was no vacuum spike and the pressure was coming down since we had turned off the heater about 2 min earlier
Summary
• The pressure squirts argue the source is closer to the IP from the 3027 gauge because the pressure seen at the 3027 gauge is too high
• The heating of the forward Q2 NEG and the HER 8020 NEG argue the vacuum spikes are between the detector and the Q2 NEG (could be in the location of the Q2 NEG)
• Unfortunately not yet able to rule out the support tube