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User name brads
Log entry time 15:00:53 on November 21, 2008
Entry number 250202
This entry is a followup to: 249957
keyword=BB Cerenkov rates with front added front shielding
Bottom line: Rates dropped by %20 after the shielding was added to the front
(vs. the previous open-front configuration).
Started 2:35pm, Friday, run 3790
Beam current: 11.8 uA
103. kHz T1 rate
1.4 kHz T3 rate
0.051 kHz T5 rate
22.5 kHz T6 rate
T7 rates w/ all HVs off (ie. EDTM pulser only, same as T2 rate)
Thresh Rate (Hz)
-100 12.48
-300 12.48
-500 12.48
-700 12.48
-750 12.48
-800 0
-900 0
### This is with the 1" of Pb on all sides but that facing the target.
### Target side has 2+" of Pb.
### 1" thick Al plates are on top and bottom.
T7 rates w/ HV on 19 on (witness PMT @ 2100V); 11.8 uA beam
Thresh Rate (kHz)
-100 83.0 (~1.5 kHz during trip)
-300 19.0 (~200 Hz during trip)
-500 6.2 ( ~40 Hz during trip - 12 Hz EDTM))
-700 4.2 ( ~30 Hz during trip - 12 Hz EDTM))
-900 3.0 ( ~4 Hz during trip)
Done 2:55pm, Friday, run 3790
### This is with the 1" of Pb on all sides but that facing the target.
## Side facing target is unshielded.
### 1" thick Al plates are on top and bottom.
### Done on Tuesday, run 3654
T7 rates w/ HV on 19 on (witness PMT @ 2100V); 11.8 uA beam
Thresh Rate (kHz)
-100 104.
-300 27.5 (~300 Hz during trip)
-500 9.3
-700 6.3
-900 4.3
### This is the first (unshielded) run
T7 rates w/ HV on 19 on (witness PMT @ 2100V); 11.8 uA beam
Thresh Rate (kHz)
-100 168.
-300 48.6
-500 17.6
-700 11.8
-900 8.8
A copy of this log entry has been emailed to: meziani