Reports until 09:53, Wednesday 17 April 2024
LHO VE
jordan.vanosky@LIGO.ORG - posted 09:53, Wednesday 17 April 2024 - last comment - 15:06, Tuesday 23 April 2024(77241)
LN2 Dewar Inspection 4/16/24 and Vacuum Jacket Pressures

During yesterday's (4/16) maintenance period, a Norco tech came to the site to inspect the 8 LN2 dewars that feed the cryopumps. Inspection report will be posted to Q2000008 once received.

The vacuum jacket pressures were also measured during inspection:

Dewar Pressure (micron/mtorr)
CP1 68 (gauge fluctuated may need replacing, lowest value recorded)
CP2 26
CP3 68
CP4 (not in service) 110
CP5 9
CP6 33
CP7 48
CP8 77 (gauge fluctuated may need replacing, lowest value recorded)

 

Comments related to this report
janos.csizmazia@LIGO.ORG - 15:06, Tuesday 23 April 2024 (77361)
Link 

Comparison between the last pressure check for all the dewar jackets:

- CP1: Jun 26th, 2023: 7 mTorr; difference: 68-7=61 mTorr; speed of pressure growth: 61 mTorr / 302 days = 0.202 mTorr/day
- CP2: Jun 26th, 2023: 5 mTorr; difference: 26-5=21 mTorr; speed of pressure growth: 21 mTorr / 302 days = 0.070 mTorr/day
- CP3: Jun 16th, 2023: 4 mTorr; difference: 68-4=64 mTorr; speed of pressure growth: 64 mTorr / 312 days = 0.205 mTorr/day
- CP4: no data, not in service
- CP5: Jun 16th, 2023: 4 mTorr; difference: 9-4=5 mTorr; speed of pressure growth: 5 mTorr / 312 days = 0.016 mTorr/day
- CP6: Jun 2nd, 2023: 5 mTorr; difference: 33-5=28 mTorr; speed of pressure growth: 28 mTorr / 326 days = 0.086 mTorr/day
- CP7: Jun 30th, 2023: 4 mTorr; difference: 48-4=44 mTorr; speed of pressure growth: 44 mTorr / 298 days = 0.148 mTorr/day
- CP8: Jul 8th, 2023: 5 mTorr; difference: 77-5=72 mTorr; speed of pressure growth: 77 mTorr / 290 days = 0.266 mTorr/day