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
One month history of LER and Diamond East
LER
East Diam
April 17
May 18
May 12
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
Pressure variations in VP3044 and VGCC3027
VP3044 VGCC3027
VP3075VP3147
Detailed history of May 12
LER
VP3044
VGCC3027
East Diam
Time in hours
0 12 24
Detailed history of May 13
LER
VP3044
VGCC3027
East Diamond
Also affects DCH and DRC(not corrected for HER increase)
DCH DIRC 0
600
1000+20 %
+20%
One month History April 17_May 18 One month History April 17_May 18
It is also thermal outgassing in DCH and DRC
DCH DRC 0
Time in hours Time in hours
More evidence that DCJ is outgassing
and NOT neutronsLER/HER/LUMI
DCH
Neutrons
Diam East
May 18
7 pm to 11 pm
Summary of May 12-13 for DIAM E
All variables normalized to 1 on MAY 18 0 am
Time in hours
DIAME
LER
VP3044
VGCC3027
HER
Summary for May 12-May 21
DIAMELERVP3044VGCC3027HER
Summary of May 12-13 for DRC and DCH
All variables normalized to 1 on MAY 18 0 am
Time in hours
LER
VP3044
DRC0
DCH
HER
Diamond East is perfectly described with two pumps vP3044
and VGCC3027
May 11 6 pm to Midnight
Diam E
VGCC3027
VP3044
14
After the start of outgassing
May 13, 8 pm to Midnight
14
25
Almost doubling of DIAME
Still true later on
May 17
3am to Midnight
The coefficients, normalised to 1 on May 10
VP3044VGCC3027
VP3075 VP3147
Days in May Days in May
Evolution of pressures and DIAM-E sensitivity coefficients
Sensor Pressure change
Coefficient
change
Total change
VP3044 X 1 X2.5 X2.5
VGCC3027 X3.5 X0.6 X2.1
DiamE x1.65
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
Pressure spike on May 22
Pressure spike on May 23
BABAR dead time driver
East Diamondrecent week
