2017/10/11 (Wednesday) · UMN CDMS Wiki archive

1209	Removing tower adapter plate.
1220	Will try taking side coaxes off while leaving the extenders completely attached. Then we won't need to desolder anything.
1229	Took off side coax ZB1-6 from DIB 4.
1238	Took off side coax ZB1-1-11 from DIB 3.
1245	Took off side coax ZB1-1-9 from DIB 1.
1250	Do electrical checks between channels at DIB level:

Pin	DIB1 qI (qA)	DIB4 qI (qB)	DIB1 qO (qC)	DIB3 qO (qD)	DIB4 qO (qE)
Detector Electrical Checkout (closed housing)				Date:	2017 Oct 11
Detector: S1502				Who:	GR DS MF
DIB1 qI (qA)	-	-	-	-	-
DIB4 qI (qB)	4.8 / 205	-	-	-	-
DIB1 qO (qC)	215	213	-	-	-
DIB3 qO (qD)	269	271	263	-	-
DIB4 qO (qE)	4.6 /…/ 910	8.4 / 220	214	271	-
all measurements in Ω.
Values past the slash were after removing and replacing the lid. Values after the /…/ were after bending the bonds with a scalpel.

	As can be seen above (first values) there are clear shorts from A to B and from A to E.
1540	Removing lid from detector housing. In so doing, pulled off a couple of the soldered nuts that formed the heads of the threaded-rod screws.
	Do detector electrical checks from DIB pins to channels on detector surface:

Pin	qA	qB	qC	qD	qE
Detector Electrical Checkout (open housing)				Date:	2017 Oct 11
Detector: S1502				Who:	NM MF
DIB1 qI (qA)	1.6	205	291	293	14
DIB4 qI (qB)	206	2.0	227	330	215
DIB1 qO (qC)	296	230	3.0	270	300
DIB3 qO (qD)	300	330	270	4.0	290
DIB4 qO (qE)	10	210	290	290	6.0
all measurements in Ω.

	As can be seen above the short from A to B seems to have disappeared since we removed the lid. The short from A to E is still present.
1605	Manipulate the bonds a bit with a scalpel. The bad bonds seemed to be both the DIB4 DIB-to-pad bonds. Each can produce a short when we push it down, and trying to bend it up removes the short. We were able to make both shorts disappear this way. They're gone whether the lid is on (see final values in first table) or off (see new table below).

Pin	qA	qB	qC	qD	qE
Detector Electrical Checkout (open housing)				Date:	2017 Oct 11
Detector: S1502				Who:	NM MF
DIB1 qI (qA)	2.0	250	441	640	900
DIB4 qI (qB)	250	2.0	260	470	750
DIB1 qO (qC)	440	260	3.0	300	630
DIB3 qO (qD)	620	470	310	4.0	440
DIB4 qO (qE)	900	750	615	440	6.0
all measurements in Ω.

1610	The detector may have shifted a little bit away from DIB4, which may have pulled these bonds tighter. Shove the crystal with the black tool as a pry rod, get it a little more centered. Then retighten all the clamp screws.
1620	Replace detector lid and attach a couple of the stack screws.

	Status: New oil in 3He pump. There is some air/N2 in the pump, and it is isolated from most of the IGH (V6 is open 100%). Pump is off. There is mixture in the Dump, Trap 2, the G1 volume, the IGH Manifold, the Vent volume, the Cryopump tubing, and the Cryopump. Cryopump is warm and open to G1, Trap 2, and Dump.
0850	G1 (dump+cryopump+Trap 2) = 882.0 mbar.
0850	P1 (3He pump inlet) = 0.4 mbar, G2 (3He pump outlet) = 119.5 mbar. 3He Pump oil level (pump off) = 60%.
0850	Turn on 3He pump. Initially rather loud, then gets quieter. No high-pitched whining.
0855	P1 (pump inlet) has fallen to 0.007 mbar. G2 (pump outlet) = 148.3 mbar. 3He Pump oil level (pump on) = 33%.
0855	Pump on 3He outlet through KF tee-port with scroll pump for about 15 seconds. New high-pitched noise from 3He pump, seems to be associated with low outlet pressure. I think this was true during the run, too. G2 (pump outlet) reduced to 77 mbar. 3He Pump oil level has changed a little, = 38%.
0900	Turn off 3He pump. Then continue pumping on 3He Pump outlet with scroll pump. G2 quickly falls to bottom of scale, 0.000 mbar.
0905	Open speedivalve to port at KF-tee to 3He pump inlet. Now we are pumping both sides with the scroll pump, and the pressure can be read on P1. P1 rises to 0.065 mbar, then begins falling.
0910	3He pump oil level = 90%, with pump off and both sides being pumped on with the scroll pump.
0910	P1 (3He pump inlet and outlet) sorta flat at 0.060 mbar. Close off ports to 3He inlet and outlet, then turn 3He pump on again. P1 falls to 0.007 mbar. 3He pump oil level (pump on) = 60%, and bubbles seen in oil.
0915	G2 (3He pump outlet) rose to 2.2 mbar. Begin pumping on 3He pump outlet with scroll pump again. G2 falls to 0.000(minimum) again.
0920	Close speedivalve to stop pumping on 3He outlet. 3He pump still on, watch G2 to see if it rises above minimum.
0925	Can see a few bubbles in oil now but much less than before.
0930	G2 has not risen. Turn off 3He pump. Then with scroll pump still attached and on, open both speedivalves to connect 3He inlet and outlet so we can again see the pressure on P1.
0930	G2 briefly reads 0.2 mbar then falls back to minimum. P1 rises to 0.4 mbar, much higher than before. Are we getting out outgassing from the oil? P1 now falling as we continue to pump both sides of 3He pump out with scroll pump.
0940	P1 (3He Pump inlet+outlet) down to 0.030 mbar and continues to fall. When pumping it out a half hour ago it sorta fluctuated around 0.060, maybe because some of those air bubbles were slowly outgassing.
1000	P1 (3He Pump inlet+outlet) = 0.020 mbar and fairly flat. Stop pumping out 3He pump - close speedivalves to inlet and outlet and turn off scroll pump.
1000	Turn on 3He pump. Some bubbles seen in the oil but not nearly as many as at 9:10.
1010	Turn off 3He pump. Begin pumping outlet and inlet again with scroll pump. Forgot that pump was off before opening speedivalves: P1 rose to 10 mbar, G2 to 4 mbar. Both fall quickly when scroll pump turned on.
1015	P1 (3He Pump inlet+outlet) = 0.100 mbar and falling
1140	P1 (3He Pump inlet+outlet) = 0.010 mbar
1145	Stop pumping on 3He pump with scroll pump, close speedivalves at inlet and outlet. Turn on 3He pump. A few bubbles seen in oil.
1155	No more bubbles seen in oil. Turn off 3He pump. Start pumping inlet and outlet with scroll pump. P1 peaks at 0.200 mbar then falls.
1305	P1 (3He pump inlet+outlet) = 0.009 mbar. Stop pumping out 3He pump, close speedivalves to inlet and outlet.
1305	Turn on 3He pump. Bubbles seen in oil after first turning it on.
1330	No bubbles seen in 3He pump oil. Turn off 3He pump, then open the inlet&outlet speedivalves to start pumping on 3He pump with scroll again. P1 peaks at 0.270 mbar then falls. (No improvement over 11:55.)
1350	P1 (3He Pump inlet+outlet) = 0.013 mbar
1350	Stop pumping on 3He pump with scroll pump, close speedivalves at inlet and outlet. Turn on 3He pump. A few bubbles seen in oil.
1420	No bubbles. Turn off 3He pump again and open speedivalves to pump it out with scroll again. P1 peaks at 0.320 mbar then falls again.
1425	P1 down to 0.018 mbar. Stop pumping out with scroll then turn 3He pump on again.
1420	Turn off 3He pump again and open speedivalves to pump it out with scroll again. P1 peaks at 0.070 mbar then falls again. (Seems to be correlated with the amount of time the 3He is running.)
1435	P1 down to 0.016 mbar. Stop pumping out with scroll then turn 3He pump on again.
1505	Turn off 3He pump again and open speedivalves to pump it out with scroll again. P1 peaks at 0.260 mbar then falls again. (Better than the last 30 minute run at 14:20.)
1520	P1 down to 0.012 mbar. Stop pumping out with scroll then turn 3He pump on again.
1550	Turn off 3He pump again and open speedivalves to pump it out with scroll again. P1 peaks at 0.200 mbar then falls again. (Better than the last 30 minute run at 15:05.)
1620	P1 down to 0.010 mbar. Stop pumping out with scroll then turn 3He pump on again.
1650	Turn off 3He pump again and open speedivalves to pump it out with scroll again. P1 peaks at 0.140 mbar then falls again. (Better than the last 30 minute run at 15:50.)
1710	P1 down to 0.011 mbar. Stop pumping out with scroll pump, close speedivalves to 3He pump inlet & outlet.