2018/04/11 (Wednesday) · UMN CDMS Wiki archive

	Status: Tower removed. Mixture cleaned several times. Cryostat vacuum jacket pumped out.
0940	Check pressure in warm LN2 Trap 1: 1.9 mbar. Pump out with scroll pump.
0945	Check pressure in warm LN2 Trap 2: 6.6 mbar. Pump out with scroll pump.
1015	Start cryocleaning mixture through cold LN2 Trap 2, V6 = 12.4%
1020	Increase V6→12.8% to restart flow
1030	Increase V6→13.0% to restart flow
1050	Increase V6→13.1% to speed up flow
1130	Stop cryocleaning. Trap 2, 75 minutes. G2 = 575 mbar. Pump mixture back to dump.
1205	Start cryocleaning mixture through cold LN2 Trap 1, V6 = 13.2%
1210	Increase V6→13.5% to restart flow
1320	Stop cryocleaning. Trap 1, 75 minutes. G2 = 579 mbar. Pump mixture back to dump.
1330	Check pressure in warm LN2 Trap 2: 2.7 mbar. Pump out with scroll pump.
1340	Start cryocleaning mixture through cold LN2 Trap 2, V6 = 13.4%
1350	Increase V6→13.5% to speed up flow
1450	Stop cryocleaning. Trap 2, 70 minutes. G2 = 590 mbar. Pump mixture back to dump.
1330	Check pressure in warm LN2 Trap 1: 14.4 mbar(???). Pump out with scroll pump.
	Very little was removed in the first cleaning today - maybe that was an anomaly.
	V6 was open more on the second cleaning, and the pressure was higher. Does this make a difference? Start recording the G2 pressure maybe.
	note that today the barometer has fallen by about 0.13 inHg, so G1 & G2 will read about 4 mbar higher now than this morning.
	for the next cleaning I'll experiment with increasing the flow rate. Will see if the tubing starts to get cold / frost up.
1535	Start cryocleaning mixture through cold LN2 Trap 1, V6 = 13.3%
1550	Increase V6→13.5% to speed up flow this caused the return tube (straight one) from the trap to get frosty. G2 peaked at 760 mbar, higher than earlier cleanings today.
	Return tube is frosty up to just below o-ring flange. Probably don't want to circulate faster than this.
1610	O-ring flange itself is a little frosty
	Frost level on trap return tube seems to fall as G2 pressure falls.
1645	Stop cryocleaning. Trap 1, 70 minutes. G2 = 618 mbar. Pump mixture back to dump.

Cryocleaning log
date	trap	duration (minutes)	contaminants removed (mbar)
Apr 6	1	70	9.5
Apr 6	2	70	6.6
Apr 6	1	70	11.0
Apr 6-7	2	overnight, no circ, dump exposed to trap	12.8
Apr 7-9	1	overnight, no circ, pump exposed to trap	6.8
Apr 9	2	70	8.9
Apr 9	1	60	9.0
Apr 10	2	90	10.5
Apr 10	1	70	8.5
Apr 10	2	75	6.6
Apr 10	1	70	1.9
Apr 11	2	75	2.7
Apr 11	1	75	14.4
Apr 11	2	70

Tower
1050	Disassembling tower. Adapter ring and side coaxes removed.
1140	Assemble source plate, bare Am source with enlarged collimator mounted at center. Using the source plate with the hole drilled out for LED light. Assemble LED plate, three IR LEDs mounted on plate. Also mount tower thermometer on plate.

+lead	- lead	signal	typical	previous/now
Detector	S101	DIB	1
		date/who:	2018-04-11	MF & NM
1	2	QET A	100 to 200 Ω	304/298 Ω
3	4	QET B	100 to 200 Ω	110/109 Ω
5	6	QET C	100 to 200 Ω	397/395 Ω
7	8	QET D	100 to 200 Ω	289/288 Ω
9	chassis	LED1 Rforward	8 to 9 MΩ	167/82 kΩ
9	chassis	LED1 Vforward	1.0 to 1.1 V	1.002/0.896 V
chassis	9	LED1 Rreverse	<1 nS	570/230 kΩ
10	chassis	LED2 Rforward	8 to 9 MΩ	750/761 kΩ
10	chassis	LED2 Vforward	1.0 to 1.1 V	1.041/1.043 V
chassis	10	LED2 Rreverse	<1 nS	<0.5 nS
11	12	Qo-Qi		n/a
12	11	Qi-Qo		n/a
1-8	chassis	<1 nS	<0.4 nS	<0.2 nS

+lead	- lead	signal	typical	before/now
Detector	S101	DIB	3
		date/who:	2018-04-11	MF & NM
1	2	QET A	100 to 200 Ω	139/177 Ω
3	4	QET B	100 to 200 Ω	26/26 Ω
5	6	QET C	100 to 200 Ω	27/27 Ω
7	8	QET D	100 to 200 Ω	open/open
9	chassis	LED1 Rforward	8 to 9 MΩ	n/a
9	chassis	LED1 Vforward	1.0 to 1.1 V	n/a
chassis	9	LED1 Rreverse	<1 nS	n/a
10	chassis	LED2 Rforward	8 to 9 MΩ	n/a
10	chassis	LED2 Vforward	1.0 to 1.1 V	n/a
chassis	10	LED2 Rreverse	<1 nS	n/a
11	12	Qo-Qi		n/a
12	11	Qi-Qo		n/a
1-8	chassis	<1 nS	<0.4 nS	<0.5 nS

+lead	- lead	signal	typical	previous/now
Detector	S101	DIB	4
		date/who:	2018-04-11	MF & NM
1	2	QET A	100 to 200 Ω	353/352 Ω
3	4	QET B	100 to 200 Ω	422/420 Ω
5	6	QET C	100 to 200 Ω	349/347 Ω
7	8	QET D	100 to 200 Ω	380/378 Ω
9	chassis	LED1 Rforward	8 to 9 MΩ	n/a
9	chassis	LED1 Vforward	1.0 to 1.1 V	n/a
chassis	9	LED1 Rreverse	<1 nS	n/a
10	chassis	LED2 Rforward	8 to 9 MΩ	n/a
10	chassis	LED2 Vforward	1.0 to 1.1 V	n/a
chassis	10	LED2 Rreverse	<1 nS	n/a
11	12	Qo-Qi		n/a
12	11	Qi-Qo		n/a
1-8	chassis	<1 nS	<0.3 nS	<0.5 nS

1200	Mount detector on tower, DIBs 1/3/4 → IT4 Tower Faces 5/3/1
1205	Mount source&LED holder on tower. The hole for the LED light is opposite DIB1 (the DIB with LEDs)
1345	Polish lower rim of 30mK can with Scotch-Brite
1415	Tower assembly in progress: The three external LED wires have been soldered to extender plug pins on DIBs 3&4 Tower ears and contact surfaces on the adapter plate were polished with Scotch-Brite Side coaxes installed in same arrangement as Run 62: DIBs 1/3/4 → Side Coaxes ST-3-3/ST-3-9/ST-3-10

1420	After assembling tower, found all phonon channels shorted to ground by a few kΩ except DIB3 PA which was shorted by only ~100 Ω. Pulling and pushing the top of the DIB3 side coax where it plugged into the connector changed the resistance. By doing this was able to find a configuration which was stable and removed the short.
1450	Tower electrical check:

+lead	- lead	signal	typical	previous/now
Detector	S101	DIB	1
side coax	ST-3-3	date/who:	2018-02-11	NM DS
face	5
1	2	QET A	100 to 200 Ω	406/401 Ω
2	4	QETA-B	100 to 200 Ω	4.24/2.7 kΩ
3	4	QET B	100 to 200 Ω	209/209 Ω
4	6	QETB-C	100 to 200 Ω	4.42/5.9 kΩ
5	6	QET C	100 to 200 Ω	495/494 Ω
6	8	QETC-D	100 to 200 Ω	3.8/3.9 kΩ
7	8	QET D	100 to 200 Ω	376/376 Ω
2	8	QETA-D	100 to 200 Ω	3.9/3.2 kΩ
9	chassis	LED1 Rforward	8 to 9 MΩ	183/94 kΩ
9	chassis	LED1 Vforward	1.0 to 1.1 V	1.053/1.04 V
chassis	9	LED1 Rreverse	<1 nS	270/275 kΩ
10	chassis	LED2 Rforward	8 to 9 MΩ	760/756 kΩ
10	chassis	LED2 Vforward	1.0 to 1.1 V	1.095/1.117 V
chassis	10	LED2 Rreverse	<1 nS	0.2/0.2 nS
All pins → Ground	<1.0nS	(Except for LED pins)		all <0.3/0.5 nS

+lead	- lead	signal	typical	previous/now
Detector	S101	DIB	3
side coax	ST-3-9	date/who:	2018-02-11	NM DS
face	3
1	2	QET A	100 to 200 Ω	246/280 Ω
2	4	QETA-B	100 to 200 Ω	3.17/2.85 kΩ
3	4	QET B	100 to 200 Ω	129/129 Ω
4	6	QETB-C	100 to 200 Ω	4.675/3.19 kΩ
5	6	QET C	100 to 200 Ω	132/132 Ω
6	8	QETC-D	100 to 200 Ω	inf/inf Ω
7	8	QET D	100 to 200 Ω	inf/inf Ω
2	8	QETA-D	100 to 200 Ω	inf/inf Ω
9	chassis	LED1 Rforward	8 to 9 MΩ	790/790 kΩ
9	chassis	LED1 Vforward	1.0 to 1.1 V	1.093/1.098 V
chassis	9	LED1 Rreverse	<1 nS	0.3/0.1 nS
10	chassis	LED2 Rforward	8 to 9 MΩ	790/795 kΩ
10	chassis	LED2 Vforward	1.0 to 1.1 V	1.092/1.099 V
chassis	10	LED2 Rreverse	<1 nS	0.2/0.2 nS
All pins → Ground	<1.0nS	(Except for LED pins)		all <0.3/0.3 nS

+lead	- lead	signal	typical	measured
Detector	S101	DIB	4
side coax	ST-3-10	date/who:	2018-04-11	MF GR
face	1
1	2	QET A	100 to 200 Ω	458/458 Ω
2	4	QETA-B	100 to 200 Ω	4.75/4.33 kΩ
3	4	QET B	100 to 200 Ω	526/526 Ω
4	6	QETB-C	100 to 200 Ω	open (flashing OL)
5	6	QET C	100 to 200 Ω	453/452 Ω
6	8	QETC-D	100 to 200 Ω	4.9/5.4 kΩ
7	8	QET D	100 to 200 Ω	483/483 Ω
2	8	QETA-D	100 to 200 Ω	5.7/6.22 kΩ
9	chassis	LED1 Rforward	8 to 9 MΩ	800/open kΩ
9	chassis	LED1 Vforward	1.0 to 1.1 V	1.093/open V
chassis	9	LED1 Rreverse	<1 nS	<0.1/0.1 nS
10	chassis	LED2 Rforward	8 to 9 MΩ	790/787 kΩ
10	chassis	LED2 Vforward	1.0 to 1.1 V	1.090/1.095 V
chassis	10	LED2 Rreverse	<1 nS	0.2/0.1 nS
All pins → Ground	<1.0nS	(Except for LED pins)		all <0.4 nS

1506	Tower checkout looks fine. Only odd things were the short mentioned above which is fixed, and the inability to measure between DIB4 QETB-C. The meter just blinks OL in either resistance or resistivity. However, these are on opposite faces, so probably it's okay and they're not shorted.