Jan 20, 2015

Test settings: DSSD biased at 100V, with 3.5 uA leakage current. Pulser at 0.5 V, split and inverted for both
positive and negative polarity. Frequency at 100 Hz.


++SHAPING TIME++

We varied shaping time (Tsh), and adjusted hold time (Th) accordingly. We measured the width of pulser spectra
for two channels using 'integrate' function of spectrum browser.

 Tsh	 Th	nnaida#11-2.6L	nnaida#13-2.6L
[usec]	[usec]	 FWHM [ch]	 FWHM [ch]
0.5	2	146		109
1	2	133		113
2	2	131		116
4	6	130		126
8	8	145		136

note: Tsh= ( 0.5*offset9 + 0.5) usec, Th= 2*offset7 usec

The first two data points where saved to file R44_0.gz, and R45_0.gz. Starting from the Tsh=2usec measurement,
NNAIDA#12 was causing communication issues with the merger/tape server, so we don't have files for last few.

Due to limited storange in AIDA PC, data was stored to external drive provided by Vic
(/media/data/TapeData/Test100/), and backued up temporarly also in Edinburhg
(/Disk/ds-sopa-personal/aestrade/data/AIDA/).


++THRESHOLDS++

Next step was to adjust threshold of the slow comparator, in order to lower them and take data looking for
background alpha radioactivity. 

At this point NNAIDA#13 had stopped producing data (probably similar issue as NNAIDA#12, which could be
recovered with power cycling FEEs), so we used nnaida#14

FEE		Eth	rate/channel	integral(pulse peak):integral(noise peak)
nnaida#11	0x40	115 Hz (~only pulser)
nnaida#14	0x40	115 Hz(~only pulser)

nnaida#14	0x20	~350 Hz			2:1

nnaida#11	0x10	~150 Hz			1:2	(one channel very noisy @ 15kHz)
nnaida#14	0x10	~5 kHz (asic 1-3)	80:1
		0x10	~3kHz-100 Hz (asic 4)


For background run (see next elog entry) threshold values set at:
 nnaida#11= 0x16
 nnaida#12= 0x40 
 nnaida#13= 0x20
 nnaida#14= 0x16