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IR 2 Vacuum Update

IR 2 Vacuum Update. M. Sullivan for PEP-II team For the 2e34 meeting of Feb. 15, 2006. Orientation A look at some of the gas squirt events NEG heating events Summary. Typical event from Feb 5th. Detector. Forward Q2 NEG. Support tube end bellows. 2.25. 122. LER. HER. 1364. 993. 0.

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IR 2 Vacuum Update

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  1. IR 2 Vacuum Update M. Sullivan for PEP-II team For the 2e34 meeting of Feb. 15, 2006

  2. Orientation • A look at some of the gas squirt events • NEG heating events • Summary

  3. Typical event from Feb 5th Detector Forward Q2 NEG Support tube end bellows 2.25 122 LER HER 1364 993 0 2.29 0 0.08 Backward Q2 NEG LER frangible link NEG pump

  4. Another typical event from Feb 5th Detector Forward Q2 NEG Support tube end bellows 0.82 27 LER HER 1653 198 0 0.54 0 0.07 Backward Q2 NEG LER frangible link NEG pump Small numbers have larger baseline subtraction errors

  5. Vacuum events with single ring LER on Sat. morning Feb 11th 100 nTorr squirt Vacuum spike Big vacuum spike

  6. Vacuum spike event at 11:50 on Feb 11th 2300 mA in LER only Detector Forward Q2 NEG Support tube end bellows 4.32 16.9 LER HER 7950 1413 0.34 2.44 0 0.60 Backward Q2 NEG LER frangible link NEG pump

  7. Squirt event at 11:51 Detector Forward Q2 NEG Support tube end bellows 0 0.29 LER HER 334 1171 0 0 0 0.07 Backward Q2 NEG LER frangible link NEG pump

  8. The highest vacuum spike event at 11:57 on Feb 11th2446 mA in LER only Detector Forward Q2 NEG Support tube end bellows 9.2 225 LER HER 3830 3672 1.16 17.2 0 2.05 Backward Q2 NEG LER frangible link NEG pump

  9. Big air event when we opened a valve Detector Forward Q2 NEG Support tube end bellows 81 3440 LER HER 0 1360000 24 240 14 479 Backward Q2 NEG LER frangible link NEG pump

  10. 10000 nTorr squirt (no beam) Detector Forward Q2 NEG Support tube end bellows 0.61 10.1 LER HER 0 9125 0.19 1.01 0.07 1.57 Backward Q2 NEG LER frangible link NEG pump Argues that the 3027 gauge sees too much pressure

  11. 10000 nTorr squirt (with beam) Detector Forward Q2 NEG Support tube end bellows 0.61 10.3 LER HER 0 8720 0.19 1.01 0.95 1.29 Backward Q2 NEG LER frangible link NEG pump Argues that the 3027 gauge sees too much pressure

  12. Heating forward Q2 NEG pump 60 nTorr

  13. Forward Q2 NEG heating with beam Detector Forward Q2 NEG Support tube end bellows 8.9 5.1 LER HER 72 60 0.08 0.38 0 0 Backward Q2 NEG LER frangible link NEG pump The 8020 pump sees too much pressure

  14. 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.

  15. Heating up HER Q5 NEG (8020) on the forward side of the detector 380 nTorr Detector backgrounds remain low

  16. Heating of 8020 NEG today -- Feb 15th HER 8020 NEG Detector Forward Q2 NEG Support tube end bellows 380 2.1 LER HER 56 20.6 0 0.42 0 0.29 Backward Q2 NEG LER frangible link NEG pump

  17. 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

  18. 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

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