2016/01/27 (Wednesday)

Previous Day

	Setup: iZIP mode, DIB1/2/3 → cables → 3.2 MHz filters → DCRC55/33/50
	Taking Y-Be photoneutron data overnight. However no flashes have occurred since 21:30 last night. Looks like the DAQ crashed. Last data written to /chocula was at 21:51.
0930	Removed strong Y source from Y-Be source holder.
0930	Tower/MC(H35)/MC sensor/Cold Plate = 31.4/27.2/41/162 mK, Still = 1.31 K / 0.12 mbar, G1/G2 = 195/180 mbar, 1K Pot = 1.72 K / 19 mbar, Main bath = 36.1%
0940	Fill LN2 cold trap Dewar.

jiajin:bin cdmssoft$ps -u cdmssoft
   PID TTY          TIME CMD
 12728 pts/1    00:00:00 bash
 96721 ?        00:14:38 lazylogger
552222 pts/9    00:00:00 bash
552417 ?        00:00:08 mserver
553923 ?        13:58:41 triggerfe2.exe
583773 pts/1    00:00:00 ps

0945	mhttpd is not running….
0950	restarted MIDAS web interface as per instructions on the MIDAS page. Started dcrc_driver, tower and trigger programs. Data-taking sequence began, so hit Stop Immediately.
1001	Start 3 hours of 30min background(bg) series at -4/+4V with FG=5/2/5, OG=3, with 1000 initial randoms, 1000 ending randoms, 30s flash and 25 minute cooldown before series. Trigger on DIB1 phA with threshold of 30ADC bins.
1430	In order to hopefully increase the neutron flux, we rearranged things to get the Y-Be source closer to the fridge. Removed the lead from the north wall of the fridge shield. Set up a platform to place the Y-Be source holder up against the mu-metal shield, situated in the window left in the poly. See photos below. Still using two layers of lead brick (4“) between Y-Be and fridge.

Vertical position of source about 1 inch below detector level.

Top of source holder flush with bottom of upper poly piece.

1505	Commence LHe transfer (27.1%).
1550	Cease LHe transfer (91.4%).
1600	Low frequency noise noticeably in phonons. Release pressure from bath.
1615	Trying to lower the trigger threshold on DIB1pA, the one that we've been triggering on (this seems to still be one of the best choices to trigger on as it is relatively low noise). Adjusting down from 30 by 2 ADC bins at a time, then using the pulse viewer to see whether there's a lot of triggers on noise. Start to see some noise triggers at thresh=20. At thresh=18 noise events seem to dominate. So we'll try 20.
1620	Fill LN2 cold trap full.
1648	Place Strong 88-Y source inside source holder near fridge.
1651	Start 15 hours of 30min Y-Be series at -4/+4V with FG=5/2/5, OG=3, with 1000 initial randoms, 1000 ending randoms, 30s flash and 25 minute cooldown before series. Trigger on DIB1 phA with threshold of 20ADC bins.

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