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LER thermal outgassing is back again with us

This report highlights a significant increase in the East Diamond signal since May 12, attributed to thermal outgassing in pumps VP3044 and VGCC3027. It occurred just before the last LER current step and was influenced by an increase in HER current. Pressure and sensitivity variations were observed in these pumps, also affecting DCH and DRC. The report provides detailed histories and evidence of thermal outgassing in relevant components.

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LER thermal outgassing is back again with us

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  1. LER thermal outgassing is back again with us • Significant increase in East Diamond signal since May 12, ~3 pm due to thermal outgassing in two pumps VP3044, VGCC3027 • Happened one day before the last LER current step (2400 mA on May 13) • Due to HER current increased from 1.3A to 1.4A • As in March, change associated with pressure AND sensitivity variations in these pumps • Seen also in DCH and DRC

  2. One month history of LER and Diamond East LER May 12 East Diam April 17 May 18

  3. Extra heating due to HER increase (thanks to Witold for pinting this out!) HER increased from 1.3 to 1.4 A From 3 pm onwards

  4. Pressure variations in VP3044 and VGCC3027 VP3044 VGCC3027 VP3147 VP3075

  5. Detailed history of May 12 LER VP3044 VGCC3027 East Diam 0 24 12 Time in hours

  6. Detailed history of May 13 LER VP3044 VGCC3027 East Diamond

  7. Also affects DCH and DRC(not corrected for HER increase) DIRC 0 DCH 1000 +20 % +20% 600 One month History April 17_May 18 One month History April 17_May 18

  8. It is also thermal outgassing in DCH and DRC DCH DRC 0 Time in hours Time in hours

  9. More evidence that DCJ is outgassingand NOT neutrons LER/HER/LUMI May 18 7 pm to 11 pm DCH Neutrons Diam East

  10. Summary of May 12-13 for DIAM E All variables normalized to 1 on MAY 18 0 am DIAME LER VP3044 VGCC3027 HER Time in hours

  11. Summary for May 12-May 21 DIAME LER VP3044 VGCC3027 HER

  12. Summary of May 12-13 for DRC and DCH All variables normalized to 1 on MAY 18 0 am LER VP3044 DRC0 DCH HER Time in hours

  13. Diamond East is perfectly described with two pumps vP3044 and VGCC3027 Diam E 14 May 11 6 pm to Midnight VGCC3027 VP3044

  14. After the start of outgassing 25 Almost doubling of DIAME May 13, 8 pm to Midnight 14

  15. Still true later on May 17 3am to Midnight

  16. The coefficients, normalised to 1 on May 10 VP3044 VGCC3027 Days in May Days in May VP3075 VP3147

  17. Evolution of pressures and DIAM-E sensitivity coefficients

  18. Conclusion • Significant increase (x1.65) of DIAME since May 12 due to thermal outagassing in VP3044 and VGCC3027 • Caused by the HER current increase from 1.3A to 1.4A • Affects also DCH and DRC • Pressure AND sensitivity variation in both pumps • VP3044 sensitivity x 2.5 • VGCC3027 reduced by a factor 2 ! • Evidence of VP3044 pressure reduction with time • Will be interesting to correlate with the many new temperature sensors

  19. Pressure spike on May 22

  20. Pressure spike on May 23

  21. BABAR dead time driver

  22. East Diamondrecent week

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