1 HBD HV Status Update Jason for the HBD crew Jan 30, 2007
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1
HBDHV Status Update
Jason
for the HBD crew
Jan 30, 2007
WEST EAST
2
1
3
0
5
4
NORTH NORTHSOUTH SOUTH
26 Jan 2007Bertan Status
T : ----------------M: ----------------B : ----------------
T:~4μA @500VM: ----------------B : ----------------
T:~8μA @500VM: ----------------B : ----------------
T : ----------------M: ----------------B : ----------------
T:~4μA @500VM: ----------------B : ----------------
T:~7μA @534VM: ----------------B : ----------------
T:~15μA @520VM: ----------------B : ----------------
T : ----------------M: ----------------B : ----------------
T:~11μA @537VM: ----------------B : ----------------
T:410nA @535VM: ----------------B : ----------------
T:~12μA @524VM: ----------------B:~26μA @520V
T:~20μA @529VM: ----------------B : ----------------
T : ----------------M: ----------------B:~26μA @550V
T:~23μA @520VM: ----------------B : ----------------
T:~11μA @430VM: dead 20MΩB : ----------------
T : ----------------M: dead 20MΩB : ----------------
T : ----------------M: dead 20MΩB:~9μA @550V
T:~24μA @550VM: ----------------B : ----------------
T:~22μA @550VM: ----------------B : ----------------
T:~37μA @500VM: ----------------B : ----------------
T:700nA @500VM: ----------------B : ----------------
T : ----------------M: dead 20MΩB : ----------------
inf resistance 20MΩ
T:540nA @500VM:76μA @500VB:51μA @520V
T : ----------------M:~46μA @300VB : ----------------
30 Jan 2007LeCroy Status
more-or-less consistentwith Bertan tests…
exceptions:• WN0, draws less current
• inf res on 13.5M short• WS2, draws less current
• 20M on mid (dead?)• 10M on 60M short
• ES4, draws more current• 20M on 25M short
Many GEMs seem to improveover time.
WS3, EN2 draw high current and trip. EN0 has a bad cable (maybe?)
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Status as of Jan. 26, 2007
TOP MID BOT
There are problems in 25 GEMs (out of 72):• 16 top • 5 middle • 4 bottom
Top GEMs… • are Au (not Cu)• thin (~300nm) CsI layer• only GEM truly exposed to HBD volume• only GEM touching the mesh’s frame• ???
T M B
5
Examples of Various GEM Behavior
3 draw low current (410, 510, 777nA) at ~500V reflecting a very high GEM impedance (0.6 – 1.3 G).
9 draw high current (ranging from 3 – 15A at about ~500V) reflecting a GEM impedance of 16 – 140M.
10 have a dead (or almost dead) short and the 10M has been replaced by a 20.
4 seem to have multi-strip problems and the 10M has been removed.
47 draw < 1nA on the way up to 520V.
T M B
T M B
T M B
6
Summary
• 25 of 72 GEMs have troubles of some kind
• most (16) are top GEMs
• Uniform distribution of problems is scary…
• GEMs showing >20M could still be more than 1 strip!
• 5 of 24 working modules (drawing appropriate current)
• 2 of these have “dead 20M” shorts (resistors replaced)
• Tentative plan for the run:
• frequent MIP peak scans (calibrations)
• swap out resistors (as needed) every access (every 2 weeks?).
EN012
EN0 EN1 EN2
TOP
MID
BOT
EN345
EN3 EN4 EN5
TOP
MID
BOT
ES012
ES0 ES1 ES2
TOP
MID
BOT
EN345
ES3 ES4 ES5
TOP
MID
BOT
WN012
WN0 WN1 WN2
TOP
MID
BOT
WN345
WN3 WN4 WN5
TOP
MID
BOT
WS012
WS0 WS1 WS2
TOP
MID
BOT
WS345
WS3 WS4 WS5
TOP
MID
BOT
TOP MID BOT TOP MID BOT
TOP MID BOT TOP MID BOT
3 draw low current (410, 510, 777nA) at ~500V reflecting a very high GEM impedance (0.6 – 1.3 G).
9 draw high current (ranging from 3 – 15A at about ~500V) reflecting a GEM impedance of 16 – 140M.
10 have a dead (or almost dead) short and the 10M has been replaced by a 20.
4 seem to have multi-strip problems and the 10M has been removed.
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