1. 2009/06/08 NKS group Okuyama Akira
summary of VDC test
2009/06/08
NKS group
Okuyama Akira

2. A channel to send a bad signal to DAQ
There is several the no signal channel when I watch a hit pattern with a source.
It is 22 channels and We can confirm 8 channels with TUL.

3. VDC hit patterns AMT hit patterns were compered
run2303 (red)
Feb normal run
HV 2kV
Vth 6.0 V
TagSUM 2 MHz
r (black)
last night
90Sr 10 cm away
Vth 3.25 V
Missing channels are not the same
12 continuous missing channels in ASD #18
Anyway we could obtain the signal from beta-rays!

4. Layer Hit Pattern (Vth=2.25)

5. VDC hit patterns Vth = 2.25 V Peaks with sharp edges
Missing channels in ASD#18 are backward region

6. VDC hit patterns Vth = 6.0 V Some peaks with sharp edges disappeared
No significant change in some of the peaks

7. Developmet of threshold level
Year/month/day
VDC Vth
HV cable
HV on
CDC IH
Mag
Note
2008/12/10
2.0
connect 0V
use ? X
higher than half cards is an oscillation
3.0
Connect
Only #5,6
2008/12/19
2.9V
Use
No oscillation
2008/12/21
2.0V
1443V
2150V
VDC lie sideway
Use 90Sr
Good hit pattern
2009/07/07
2.25V
1333V
2000V
0~4 counts