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2017/10/12 (Thursday)

Previous Day

DCRC testing

1130 DCRC6 (from Berkeley) is now set up on the PAN network. Begin testing.
DCRC Triggering P Length P pre Q Length (dec) Q Length (bin) Q pre Lasts (min) Outcome
6 Rand 20Hz 8192 0 4096 1000000000000 0 >5 Pass
6 Rand 20Hz 8192 0 3928 111101011000 0 >40 Pass
1220 Strange that it didn't fail. Maybe there's some other important setting. Run it again using DCRC1's settings, just changing the IP address in Midas.
DCRC Triggering P Length P pre Q Length (dec) Q Length (bin) Q pre Lasts (min) Outcome
6 Rand 20Hz 8192 500 151384 111101011000 500 >10 Pass

Tower Disassembly/Reassembly

Status: shorts between pA, pB, pE were clear yesterday after removing side coaxes. Shorts are now fixed by bending the DIB4 wirebonds, but not sure that it's a permanent fix. Crystal was recentered in its clamps and clamps retightened.
1028 Remove tower from purge cabinet
1030 Check interchannel resistances at DIB level. There are still no shorts.
1035 Bang the detector around a little by tilting the stand, then setting it back to upright roughly. One of the shorts reappears: DIB1 qI (qA) to DIB4 qO (qE) is about 18 Ω.
1040 Remove lid from detector. Push up DIB4 DIB-to-pad wirebonds more aggressively with scalpel. This time it looks like I've actually formed a significant arc, so that the bonds are not close to touching qA.
1045 Bang the detector around again. Check resistances - no shorts. Am I convinced??
1055 Remove lid again and check DIB-to-surface resistances, checking all segments of the segmented channels. All look good, < 4 Ω to the connected channel, > 200 Ω to the non-connected. Replace lid.
1055 Bang the detector around again and check resistances at DIB. No shorts. We'll redo the table:
Detector Electrical Checkout (closed housing) Date: 2017 Oct 12
Detector: S1502 Who: GR MF
Pin DIB1 qI (qA) DIB4 qI (qB) DIB1 qO (qC) DIB3 qO (qD) DIB4 qO (qE)
DIB1 qI (qA) - - - - -
DIB4 qI (qB) 267 - - - -
DIB1 qO (qC) 467 268 - - -
DIB3 qO (qD) 665 495 326 - -
DIB4 qO (qE) 959 783 641 451 -
all measurements in Ω.
1110 Tighten detector housing lid. For the two screws whose heads broke off, just put a nut on the exposed threaded rod. One of these was sticking out enough to put the thermometer on.
1130 Attach Side Coax ZB1-1-9 to DIB1.
1150 Attach Side Coax ZB1-6 to DIB4.
1200 Attach Side Coax ZB1-1-11 to DIB3.
1205 Also replace all the copper foil shields on the bottom of the side coax extenders.
DIB4 wirebonds, before bending them
DIB4 wirebonds, after bending them
1330 Perform tower electrical checkout:
Tower Level Checkout
Detector S1502 Date 2017-10-12 Who GR DS
DIB 1 Face 5 Side Coax ZB1-1-9
+lead - lead signal typical prev. measured
11 14 Det cont, Rbias 12 to 13 nS 13 nS 13 nS
12 11 Qo C coupling <1 nS 0.4 nS 0.1 nS
12 13 Qo Rfeedback 24 to 26 nS 26 nS 26 nS
15 14 Qi C coupling <1 nS 0.4 nS 0.1 nS
15 16 Qi Rfeedback 24 to 26 nS 26 nS 26 nS
1 11 Electrode isol <1 nS 0.11 nS 0.11 nS
All pins chassis isolation <1.0nS <1 nS <1 nS
DIB 3 Face 3 Side Coax ZB1-1-11
+lead - lead signal typical prev. measured
11 DIB4 11 Det cont, Rbias 12 to 13 nS 13 nS 13 nS
12 11 Qo C coupling <1 nS 0.1 nS 0.5 nS
12 13 Qo Rfeedback 24 to 26 nS 26 nS 26 nS
15 14 Qi C coupling <1 nS - 0.1 nS
15 16 Qi Rfeedback 24 to 26 nS 25 nS 25 nS
2 chassis LEDa Rforward 8 to 9 MΩ 0.8 MΩ 0.8 MΩ
2 chassis LEDa Vforward 1.0 to 1.1 V 1.090 V 1.090 V
chassis 2 LEDa Rreverse <1 nS 0.1 nS 0.7 nS
chassis 4 LEDb Rforward 8 to 9 MΩ 52 kΩ 60 kΩ
chassis 4 LEDb Vforward 1.0 to 1.1 V 0.782 V 0.8 V
4 chassis LEDb Rreverse <1 nS 59 kΩ 62 kΩ
6 chassis LEDc Rforward 8 to 9 MΩ 0.79 MΩ 0.78 MΩ
6 chassis LEDc Vforward 1.0 to 1.1 V 1.090 1.1 V
chassis 6 LEDc Rreverse <1 nS 0.1 nS 0.6 nS
chassis 8 LEDd Rforward 8 to 9 MΩ 38 kΩ 38 kΩ
chassis 8 LEDd Vforward 1.0 to 1.1 V 0.78 V 0.8 V
chassis 8 LEDd Rreverse <1 nS 37 kΩ 39 kΩ
All pins chassis isolation <1.0nS <1 nS <1 nS
DIB 4 Face 2 Side Coax ZB1-6
+lead - lead signal typical prev. measured
11 14 Det cont, Rbias 12 to 13 nS 13 nS 13 nS
12 11 Qo C coupling <1 nS 0.2 nS 0.2 nS
12 13 Qo Rfeedback 24 to 26 nS 26 nS 26 nS
15 14 Qi C coupling <1 nS 0.3 nS 0.2 nS
15 16 Qi Rfeedback 24 to 26 nS 26 nS 26 nS
All pins chassis isolation <1.0nS <1 nS <1 nS
1350 Attach adapter ring to tower

Changing 3He Pump Oil

Status: New oil in 3He pump. Yesterday, cycled between running the 3He Pump and pumping it out with the scroll pump. 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.
0900 P1 = 0.340 mbar. Slow increase overnight, possibly just air leaking in from outside. 3He pump was off and isolated overnight.
0900 Pump out 3He pump through inlet&outlet ports with scroll pump.
0905 3He pump oil level = 85%.
0925 P1 (3He Pump inlet&outlet) = 0.012 mbar. Close speedivalves to stop pumping it with scroll pump. Turn on 3He pump. Oil level = 60%, no bubbles.
0955 Turn off 3He pump. Pump on both sides of 3He Pump with scroll pump. Oil level changes from 65→69%. P1 peaks at 0.075 mbar. This continues the trend of less air coming out with each cycle.
1010 P1 (3He Pump inlet&outlet) = 0.012 mbar. Close speedivalves to stop pumping it with scroll pump. Turn on 3He pump. Oil level 80% → 60%, no bubbles.
1040 Turn off 3He pump. Pump on both sides of 3He Pump with scroll pump. P1 peaks at 0.080 mbar. No better than last time.
1215 P1 (3He Pump inlet&outlet) = 0.009 mbar. Close speedivalves to stop pumping it with scroll pump. Turn on 3He pump. Oil level 78% → 66%. Could see some small bubbles after turning it on, no big rising ones - these are smaller and seem to go right-to-left.
1245 Turn off 3He pump. Pump on both sides of 3He Pump with scroll pump. P1 peaks at 0.040 mbar. Another improvement.
1315 P1 (3He Pump inlet&outlet) = 0.009 mbar. Close speedivalves to stop pumping it with scroll pump. Turn on 3He pump. Oil level 83% → 73%. Some small bubbles like last time.
1345 Turn off 3He pump. Pump on both sides of 3He Pump with scroll pump. P1 peaks at 0.050 mbar. About the same. Oil level → 69%. There were also some spikes in G2 (3He Pump outlet), up to 0.3 mbar, a little before turning off the 3He pump. A little strange, maybe just a gauge glitch.
1415 G2 is still spiking while pumping on both sides with scroll pump. Must be glitchy behavior.
1420 P1 (3He Pump inlet&outlet) = 0.009 mbar. Close speedivalves to stop pumping it with scroll pump. Turn on 3He pump. Oil level 80% → 69%. Some small bubbles like before.
1450 Turn off 3He pump. Pump on both sides of 3He Pump with scroll pump. P1 peaks at 0.038 mbar, a little better. Oil level 63% → 70%.
1550 P1 (3He Pump inlet&outlet) = 0.009 mbar. Close speedivalves to stop pumping it with scroll pump.
Ready to hook the 3He Pump back up to the IGH. Now we will pump the mixture out of the cryopump and into the dump.
1555 G1 (dump + cryopump + trap 2) = 881.0 mbar. Open valves: Cryopump black valve, Vent speedivalve, V7, V2, V4, V12b+speedivalve. Also V6 is open 100%.
1600 Close V6, isolating 3He pump. Close V4, isolating dump.
1605 Open V8, connecting the Cryopump + Trap 2 to the P1 volume. P1→offscale (1000.0 mbar), G1 (cryopump + Trap 2) falls to 118 mbar.
1610 Open V9, connecting the Dump to the 3He Pump outlet. G2 (Dump + 3He outlet) rises to 689 mbar.
1615 Turn on 3He Pump. Sound is relatively mellow. G2 (Dump + 3He outlet) → 708 mbar.
1615 Open V6 to 13.5%. G2 starts increasing and G1 falls as we pull mixture out of cryopump and Trap 2 into dump. G1 quickly falls below 20 mbar.
1620 G1 (cryopump+Trap 2) = 2.3 mbar and falling. G2 (dump) = 730.3 mbar. Open V6 to 15%.
1630 G1/P1 (cryopump+Trap 2) = 1.7(flat)/0.5(falling) mbar. G2 (dump) = 732.4 mbar. Open V6 to 100%.
1635 Close V12b+speedivalve, isolating Trap 2. We can continue pumping Trap 2 later, but now we'll focus on pumping out the cryopump thoroughly.
1640 Also close V2, isolating the G1 volume. We'll monitor pressure with P1. Pumping out cryopump through cryopump black valve, Vent speedivalve, V7, V8, V6.
1645 3He Pump oil level = 40%. There's a sort of wiggling meniscus of oil below the float now.
1645 P1 (cryopump) = 0.340 mbar and falling. G2 (dump) = 734.0 mbar, slowly and steadily rising (around 10 mbar/hour).
1645 Close V8 for a few seconds as a test: P1 falls quickly. So we are certainly slowly pulling gas out of the cryopump. Try the same thing with the black cryopump valve, same thing happens although the drop in P1 is much slower, so pulling gas through the hose is kinda slow too.
1655 Close V6 as a test.
1705 With V6 closed, P1 (cryopump) has risen to 0.45 mbar. G2 (dump) = 736.9 mbar. It's still increasing although a little more slowly. So the increase in dump pressure is roughly equal parts pulling mix out of the cryopump and pulling mix out of the 3He pump itself.
1710 Open v6 100% again. P1 (cryopump) quickly falls to 0.22 mbar. We'll pump on the cryopump overnight.
1725 P1 (cryopump) = 0.180 mbar and falling. G2 (dump) = 738.5 mbar and rising.

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