2016/08/30 (Tuesday) · UMN CDMS Wiki archive

	Setup: DIB1/2/3 → 3.2 MHz filters → nothing/disconnector board/remapping board → HVside2board → DCRC55(1)/50(3). Disconnector board has all charge lines disconnected.
	DCRCs powered overnight. Exchange gas in IVC. Mixture in Dump.
0945	Tower temp = 297K.
	Set up clean tent around IVC.
1015	Overpressurize IVC with N2 gas.
1030	Begin electrical check at room temperature (differences from yesterday in bold):

	DIB1: QIbias→QObias=13nS, QIbias→QET ret=25nS QIfb→Drain/Source <1nS, QIfb→chassis=6Ω QET ret→chassis~6nS SquidC/SquidC ret→chassis~6nS QETB→ret = 5MΩ or open Last QETB ret→chassis 2Ω (short) QiBias→chassis=6 nS and QiBias/QoBias→QET ret=25 nS
	DIB2: QETB→ret=open, 89Ω, 103Ω, 90Ω QIbias/Qobias→ret=25 nS (instead of <1 nS) QIfb→Drain/Source=23/23nS, QIfb→chassis <1nS QOfb→Drain/Source=23nS, QOfb→chassis<1nS FET Tsense+→FET heater- = 0.75V (normal), QET rets→chassis ~5nS SquidA/SquidA ret→chassis=6 nS, Qibias/Qobias→chassis= 6nS
	DIB3: Squid Bias D→ret (still stable) 3.1kΩ QETs/QETrets→chassis ~6nS QIfb/QOfb→chassis <1nS Bfb/Bfb ret→chassis~6nS

1105	Open IVC, keeping an eye on DIB1 shorts and other electrical issues, removing the IVC bottom and slight jiggling of DIB1 and DIB2 resulted in no noticeable change in electrical issues on DIB1 or DIB2.
1127	Start removing screws and heatsinks on 4K stage. Monitor for changes in electrical check. No significant change in checkout, though many of the connections to chassis (excluding QET or QET returns to chassis) were reduced from ~6nS to ~4nS. QET and QET ret to chassis to chassis are now ~5 nS. Not sure if this is significant.
1143	After unscrewing DIB2 SQUID from the tower, the shorts seen on DIB1, particularly QIfb and last QET B ret line to chassis disappeared, both now show <1nS. Jiggling or adjusting the SQUID does not bring the short back, though perhaps because we are not putting excessive tension or torque on the electronics.
1148	Remove DIB2 from tower after electrical check that reveals no change. It is then noticed that by angling the cables leading from Ebox, we are able to make the shorts from Qifb and QET B ret line to chassis appear and disappear. These shorts seem to be based on the cable, and not on the tower, which makes sense since we were taking data just fine earlier. After switching gender changers we could not make the short reappear, so that is the likely culprit, though we cannot rule out the cable itself. Using the bad gender changer with DIB2 showed QIfb to chassis to be 2Ω when we knew it to be isolated. Inspecting the gender changer showed that pin 50 (QI feedback) had been smashed. It is very possible that this gender changer has been swapped around and is responsible for some of the issues we saw with QI feedback. A quick electrical check on DIB1 with a new gender changer from the HV box(the only DIB that had used the bad gender changer since the start of the warm up) showed no issues with shorts to ground from QIfeedback or the last QET B ret line. Continue with uninstall.

1342	Remove tower. Noticed a piece of kapton tape stuck to the outside of DIB1's coax, ST-3-9
	Perform tower electrical check. Note these LEDs are connected opposite to normal.

+lead	- lead	signal	typical	measured
Detector	G106a	DIB	1
side coax	ST-3-9	date/who:	2016-08-30	AK & NM
face	1
1	2	QET A	100 to 200 Ω	136 Ω
2	4	QETA-B	100 to 200 Ω	218 Ω
3	4	QET B	100 to 200 Ω	203 Ω
4	6	QETB-C	100 to 200 Ω	227 Ω
5	6	QET C	100 to 200 Ω	197 Ω
6	8	QETC-D	100 to 200 Ω	209 Ω
7	8	QET D	100 to 200 Ω	162 Ω
2	8	QETA-D	100 to 200 Ω	188 Ω
9	chassis	LED1 Rforward	8 to 9 MΩ	<1nS
chassis	9	LED1 Vforward	1.0 to 1.1 V	1.109 V
chassis	9	LED1 Rreverse	<1 nS	767 kΩ
10	chassis	LED2 Rforward	8 to 9 MΩ	<1nS
chassis	10	LED2 Vforward	1.0 to 1.1 V	OL
chassis	10	LED2 Rreverse	<1 nS	<1 nS
1	11	Qo Rbias	24 to 26 nS	25 nS
12	11	Qo C coupling	<1 nS	<0.5 nS
12	13	Qo Rfeedback	24 to 26 nS	25 nS
1	14	Qi Rbias	24 to 26 nS	25 nS
15	14	Qi C coupling	<1 nS	<0.5 nS
15	16	Qi Rfeedback	24 to 26 nS	25 nS

+lead	- lead	signal	typical	measured
Detector	G106a	DIB	2
side coax	ST-3-10	date/who:	2016-08-30	AK & NM
face	4
1	2	QET A	100 to 200 Ω	213 Ω
2	4	QETA-B	100 to 200 Ω	197 Ω
3	4	QET B	100 to 200 Ω	135 Ω
4	6	QETB-C	100 to 200 Ω	196 Ω
5	6	QET C	100 to 200 Ω	181 Ω
6	8	QETC-D	100 to 200 Ω	186 Ω
7	8	QET D	100 to 200 Ω	134 Ω
2	8	QETA-D	100 to 200 Ω	207 Ω
9	chassis	LED1 Rforward	8 to 9 MΩ	<1 nS
chassis	9	LED1 Vforward	1.0 to 1.1 V	1.096 V
chassis	9	LED1 Rreverse	<1 nS	761 kΩ
10	chassis	LED2 Rforward	8 to 9 MΩ	3 nS
chassis	10	LED2 Vforward	1.0 to 1.1 V	1.095 V
chassis	10	LED2 Rreverse	<1 nS	230 kΩ
1	11	Qo Rbias	24 to 26 nS	26 nS
12	11	Qo C coupling	<1 nS	<0.4 nS
12	13	Qo Rfeedback	24 to 26 nS	26 nS
1	14	Qi Rbias	24 to 26 nS	25 nS
15	14	Qi C coupling	<1 nS	<0.4 nS
15	16	Qi Rfeedback	24 to 26 nS	26 nS

+lead	- lead	signal	typical	measured
Detector	G106a	DIB	3
side coax	ST-3-3	date/who:	2016-08-30	AK & NM
face	5
1	2	QET A	100 to 200 Ω	198 Ω
2	4	QETA-B	100 to 200 Ω	240 Ω
3	4	QET B	100 to 200 Ω	219 Ω
4	6	QETB-C	100 to 200 Ω	179 Ω
5	6	QET C	100 to 200 Ω	166 Ω
6	8	QETC-D	100 to 200 Ω	175 Ω
7	8	QET D	100 to 200 Ω	150 Ω
2	8	QETA-D	100 to 200 Ω	206 Ω
9	chassis	LED1 Rforward	8 to 9 MΩ	8 MΩ
chassis	9	LED1 Vforward	1.0 to 1.1 V	1.104 V
chassis	9	LED1 Rreverse	<1 nS	758 kΩ
10	chassis	LED2 Rforward	8 to 9 MΩ	490 kΩ
chassis	10	LED2 Vforward	1.0 to 1.1 V	1.090 V
chassis	10	LED2 Rreverse	<1 nS	200 kΩ
1	11	Qo Rbias	24 to 26 nS	<1 nS
12	11	Qo C coupling	<1 nS	<1 nS
12	13	Qo Rfeedback	24 to 26 nS	<1 nS
1	14	Qi Rbias	24 to 26 nS	<1 nS
15	14	Qi C coupling	<1 nS	<1 nS
15	16	Qi Rfeedback	24 to 26 nS	<1 nS

1405	Tower looks good except DIB3 Rfeedback. This charge channel isn't connected, but the side coax electronics should still be good. We'll check out side coaxes to be sure.

+lead	- lead	signal	typical	measured
Side coax	ST-3-9
	date:	2015-06-27	who:	DS NM

D11	T11	Qo Rbias	25 nS	25 nS
T12	T13	Qo Rfeedback	25 nS	25 nS
D11	T12	Qo C coupling	<1 nS	<1 nS
D12	T14	Qi Rbias	25 nS	25 nS
T15	T16	Qi Rfeedback	25 nS	25 nS
D12	T15	Qi C coupling	<1 nS	<1 ns
D(1-10)	T(1-10)	LEDs, Phonons	?	<25Ω

+lead	- lead	signal	typical	measured
Side coax	ST-3-10
	date:	2015-06-27	who:	DS NM

D11	T11	Qo Rbias	25 nS	27 nS
T12	T13	Qo Rfeedback	25 nS	26 nS
D11	T12	Qo C coupling	<1 nS	<1 nS
D12	T14	Qi Rbias	25 nS	25 nS
T15	T16	Qi Rfeedback	25 nS	26 nS
D12	T15	Qi C coupling	<1 nS	<1 ns
D(1-10)	T(1-10)	LEDs, Phonons	?	<25Ω

+lead	- lead	signal	typical	measured
Side coax	ST-3-3
	date:	2015-06-27	who:	DS NM

D11	T11	Qo Rbias	27 nS	26 nS
T12	T13	Qo Rfeedback	25 nS	<1 nS
D11	T12	Qo C coupling	<1 nS	<1 nS
D12	T14	Qi Rbias	25 nS	26 nS
T15	T16	Qi Rfeedback	25 nS	<1 nS
D12	T15	Qi C coupling	<1 nS	<1 ns
D(1-10)	T(1-10)	LEDs, Phonons	?	<25Ω

1444	Side coax electrical tests confirm ST-3-3 QI,QO feedback resistors are disconnected. Visual inspection confirms broken wire bonds on Rfeeback's. However, no shorts to chassis are seen on any side coax.

1517	Perform detector check on G106a

+lead	- lead	signal	typical	measured
Detector	G106A	DIB	1
		date/who:	2016-08-30	AK NM
1	2	QET A	100 to 200 Ω	30.1 Ω
3	4	QET B	100 to 200 Ω	91.6 Ω
5	6	QET C	100 to 200 Ω	89.7 Ω
7	8	QET D	100 to 200 Ω	57.8 Ω
9	chassis	LED1 Rforward	8 to 9 MΩ	<1 nS
chassis	9	LED1 Vforward	1.0 to 1.1 V	1.040 V
chassis	9	LED1 Rreverse	<1 nS	753 kΩ
10	chassis	LED2 Rforward	8 to 9 MΩ	<1 nS
chassis	10	LED2 Vforward	1.0 to 1.1 V	open
chassis	10	LED2 Rreverse	<1 nS	<1nS
11	12	Qo-Qi		58.0Ω
12	11	Qi-Qo		55.4Ω

+lead	- lead	signal	typical	measured
Detector	G106A	DIB	2
		date/who:	2016-08-30	AK NM
1	2	QET A	100 to 200 Ω	102.3 Ω
3	4	QET B	100 to 200 Ω	30.5 Ω
5	6	QET C	100 to 200 Ω	74.6 Ω
7	8	QET D	100 to 200 Ω	29.7 Ω
9	chassis	LED1 Rforward	8 to 9 MΩ	<1 nS
chassis	9	LED1 Vforward	1.0 to 1.1 V	1.039 V
chassis	9	LED1 Rreverse	<1 nS	750 kΩ
10	chassis	LED2 Rforward	8 to 9 MΩ	3 nS
chassis	10	LED2 Vforward	1.0 to 1.1 V	1.038 V
chassis	10	LED2 Rreverse	<1 nS	718kΩ
11	12	Qo-Qi		50.6Ω
12	11	Qi-Qo		45.5Ω

+lead	- lead	signal	typical	measured
Detector	G106A	DIB	3
		date/who:	2016-08-30	AK NM
1	2	QET A	100 to 200 Ω	94.6 Ω
3	4	QET B	100 to 200 Ω	114.0 Ω
5	6	QET C	100 to 200 Ω	66.6 Ω
7	8	QET D	100 to 200 Ω	61.9 Ω
9	chassis	LED1 Rforward	8 to 9 MΩ	~15MΩ
chassis	9	LED1 Vforward	1.0 to 1.1 V	1.040 V
chassis	9	LED1 Rreverse	<1 nS	748 kΩ
10	chassis	LED2 Rforward	8 to 9 MΩ	490kΩ
chassis	10	LED2 Vforward	1.0 to 1.1 V	1.027 V
chassis	10	LED2 Rreverse	<1 nS	203kΩ
11	12	Qo-Qi		open
12	11	Qi-Qo		open

1315	Turn on He3 pump and open V9 to let mix settle in G2.
1705	G2 reads 783mbar. Barometric pressure = 30.13in. Correcting for barometric pressure as covered here, we get 790mbar of mixture in the dump. P2 currently reads 0.30mbar, so perhaps more can be pumped out of the fridge. Will do so tomorrow.
1710	After removing tower, 30mK can, outer 4K can, 100mK can lower half, now remove spool. Now we can remove the top part of the 4K can in order to get at the 600mK rod.
2000	Remove top portion of 4K can and remove 600 mK rod. Use copper tape to recover gaps in top portion of 4K can, and reattach 4K can. Reattach spool and kapton tape up the MC and tower thermometer (tie up with dental floss) while cleaning top flange and stripeline flange. Seal up top flange and stripeline flange (must retighten tomorrow). Reattach the stripline top buckle to keep stripelines in place. Thats it for today, bag/tape it all up to keep clean overnight.