SLIDE 1
1
2
Summary of HV tests Operation meeting 28.07.2017 K.Fusshoeller, - - PowerPoint PPT Presentation
Summary of HV tests Operation meeting 28.07.2017 K.Fusshoeller, - - PowerPoint PPT Presentation
Summary of HV tests Operation meeting 28.07.2017 K.Fusshoeller, L.Molina Bueno, P.Cotte 1 Schematics of detector and nominal HV configuration 2 3 4 Temperature sensors Used those 5 Pressure sensors Pressure sensors Diff Pressure
SLIDE 2
SLIDE 3
3
SLIDE 4
4
SLIDE 5
5
Temperature sensors Used those
SLIDE 6
6
Pressure sensors Pressure sensors
Absolute Pressure in tank Diff Pressure tank - atm Diff Pressure tank-insolation
SLIDE 7
7
Summary of previous test results (28-06 → 05-07)
- Grid is the most sensitive part of the HV system, always trips
first
- Liquid level above grid and maximum grid voltage (before trip)
seem correlated (the more liquid above, the higher the voltage)
- Short time variation of liquid level does not seem to be
correlated to max voltage
- Grid trip can provoke LEM trip, with or without delay
– Which LEMs trip depends on which grid connection is used
SLIDE 8
8
Heinzinger ground connection problem (07.07 and 17.07)
SLIDE 9
9
SLIDE 10
10
cathode_2017_07_17 Cathode falls to 0 by itself Unknown phenomenon
SLIDE 11
11
Was a cable problem. Has been fixed.
SLIDE 12
4 trips 8 trips 4 trips 12 trips 4 trips 13 trips 5 trips 20 trips 4 trips 12 trips 4 trips 10 trips 8 trips 19 trips 4 trips 12 trips 5 trips 13 trips 7 trips 23 trips 4 trips 10 trips 4 trips 7 trips CRP2 CRP3 CRP1 CRP5 CRP6 CRP7 CRP8 LEM Up LEM Down
N S
T
- tal number of trips per LEMs since last meeting
SLIDE 13
13
Main results of the new tests:
(details of all the tests at the end of the presentation)
SLIDE 14
14
1st test: 14h between 17th and 18th
Overview of grid, LEMs, liquid level, temperature and pressure during the test
SLIDE 15
15
Grid
Trip
SLIDE 16
16
LEMs down
Grid trip induces Current on LEMs But no trip
SLIDE 17
17
LEMs up
SLIDE 18
18
Level meters
SLIDE 19
19
Temperatures
gas liquid
SLIDE 20
20
Pressures
SLIDE 21
21
2nd and 3rd tests:
- Grid reached 5.5kV
- Grid held 5kV for 8 hours
Overview of grid and LEM
SLIDE 22
22
Trips while going to 5.6kV
SLIDE 23
23
LEMs up manually put to 0 after trip LEMs down tripped with grid except 2, 5 and 12
SLIDE 24
24
Grid stable for ~8h at 5kV, then trips
SLIDE 25
25
LEM 9 tripped ~2h after grid on up side And on down side
SLIDE 26
26
Question: is the max voltage on the grid dependent on the voltage on the cathode?
SLIDE 27
27
Cathode voltage (kV) Maximum reached on Grid (kV)
So it seems...
SLIDE 28
28
Other question: is the max voltage on the grid dependent the ramping speed?
SLIDE 29
29
Does not seem so...
SLIDE 30
30
Other question: is there a link between the variations of pressure and liquid level and the run stability?
SLIDE 31
31
12→13.07.2017 14→15.07.2017 25.07.2017 particularly stable and yet trips 26→27.07.2017 = trip No obvious correlation, but study needs refining
SLIDE 32
32
12→13.07.2017 14→15.07.2017 25.07.2017 particularly stable and yet trips 26→27.07.2017 Again, no obvious correlation
SLIDE 33
33
For information : Cathode stability
(example of test with grid at 5kV for 8h (26-27/07)
SLIDE 34
34
Cathode voltage and current
SLIDE 35
35
RMS of Cathode voltage RMS of Cathode current
SLIDE 36
36
Conclusion
- Possible link between max grid voltage and Cathode voltage:
drift field lines will be modelised with Comsol to understand
- Trying higher Cathode voltages
- Need finer study to conclude on correlation between variation of
liquid or pressure and HV stability
SLIDE 37
37
Thank you for your attention
SLIDE 38
38