2009/06/08 NKS group Okuyama Akira summary of VDC test 2009/06/08 NKS group Okuyama Akira
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.
VDC hit patterns AMT hit patterns were compered run2303 (red) Feb. 2009 normal run HV 2kV Vth 6.0 V TagSUM 2 MHz r0000019 (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!
Layer Hit Pattern (Vth=2.25)
VDC hit patterns Vth = 2.25 V Peaks with sharp edges Missing channels in ASD#18 are backward region
VDC hit patterns Vth = 6.0 V Some peaks with sharp edges disappeared No significant change in some of the peaks
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