2011/03/27

0959	Stop flashing detector
1028	Filled N2 cold trap.
1127	Trigger bits and thresholds have to be set in 'SCDMS_DetectorReadout.vi'. The MultiDAQ vi only matches trigger bits but it doesn't configure the trigger setting to the board.
1326	Experiment different ways to neutralize Q1 and Q3. Take files with 500 randoms + 500 events to check if Q1 and Q3 are responsive.
	Start to take data 07110327_1326_F0001, -4V on Q1-4. Trigger: Q1(28ADC) OR Q2(30ADC) OR Q3(30ADC) OR Q4(30ADC); coincidence time 50us. Trace length 1024, lookback time 100us. Tower T=57.5mK.
1358	Q1 and Q3 are still not very responsive in 07110327_1326 even after overnight baking. The event fraction for Q1-4 are [0.0130, 0.6089, 0.0569, 0.3212]. I'll try flashing the detector with positive bias to force the surface to neutralize.
1407	Flash the detector with +4V on Q1-4.
1516	Set bias to 0V on Q1-4. Keep flashing.
1533	Stop flashing detector.
1607	Start taking data 07110327_1607_F0001 after flashing. -4V on Q1-4. Trigger: Q1(28ADC) OR Q2(30ADC) OR Q3(30ADC) OR Q4(30ADC); coincidence time 50us. Trace length 1024, lookback time 100us.
	The trigger rate of the run was very low and the two boards didn't seem to be synchronized. Stop the run.
1612	Took new series 07110327_1612_F0001 after re-setting the timing link. Trigger rate was recovered. Q1&3 looked more responsive on the screen.
1642	Stop the run after 30min.
1750	Filled N2 cold trap.

After flashing with positive bias

After flashing with the charge electrodes positively biased and then biased at 0V, I took some data to check the neutralization effects. The primary events fractions of Q1-Q4 are [0.0720, 0.5503, 0.0294, 0.3483]. Q1 and Q3 were still weak after flashing. The energy in the figures is not calibrated. The cuts are defined as

cQ# = max([Q1, Q2, Q3, Q4], [], 2)==#
cQCchisq = cQ1chisq & cQ2chisq & cQ3chisq & cQ4chisq;
cE = 45<Qsum.

chisq cuts of Q1-Q4

Neutralization of Q1-Q4
The figures below plot the primary events as a function of time. Q1 and Q3 have much fewer events than Q2 and Q4.

Charge energy spectrum