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2012/09/30

0025 All nitrogen appears to have been extracted from the main bath. Helium leak rate 2.7E-9 mbar l/s.
Pump mixture into dump in preparation for throughput test.
0045 Evacuate main bath and 1 K pot. Background helium leak rate 6.2E-9 mbar l/s. Overpressurise main bath with He-4 gas. Helium leak rate 6.6E-9 mbar l/s: no gross leak.
0055 Background helium leak rate 7.8E-9 mbar l/s. Helium leak rate has been rising gradually, most likely to due to helium background in laboratory since blowing nitrogen out of main bath. Nothing to worry about.
Throughput test yields 55 mbar/min: higher than expected. Helium leak rate 7.9E-6 mbar l/s: no gross leak.
Isolate leak checker. Evacuate IVC with turbo pump.
0120 Fill IVC with 0.046 mbar He-4 exchange gas.
0135 Commence first helium transfer.
0355 Close gate valve and condenser line speedivalve. Restart cryocleaning mixture through nitrogen cold trap 2.
0410 Fed Cricket 4 pellets. He refuses to eat one of them. He's probably staying still to conserve body heat.
0520 Have been filling the main bath with cold helium gas to perform a test. Currently, there is no liquid in the main bath (well the level isn't as high as the level meter), but the mixing chamber has cooled to 7.7 K. Pump out He-4 exchange gas. Will wait for cryostat to warm up a little, and then fill the main bath with liquid helium.
0525 Fill N2 cold trap full.
0700 Mixing chamber still cooling, but rate of decent has slowed significantly. Mixing chamber temperature is currently just under 7.2 K. Turn on He-4 gas and start transfering helium a little quicker.
0735 Conclude first helium transfer. Helium liquid level 90.9%.
1930 Fill N2 cold trap full. Will leave mixture to cryoclean for another hour or so before pumping into the dump in preparation for condensation.
Mixing chamber temperature just shy of 7.2 K and rising: looks good.
2230 Conduct electrical check at mixing chamber temperature of 7.3 K: no shorts to ground, but encountered a couple of problems:
On DIB 1, SQUID bias B - return charges like a capacitor. Stopped reading resistance between contacts after 150 Ω due to boredom. Not sure what's causing this. This SQUET card has been well tested by us, electrical checks during Run 31 didn't show any signs of this behaviour, and nothing was seen at higher temperatures. Unsure if this points to the cause. Will keep an eye on it once we hit base temperature.
On DIB 2, Qi bias - QET return has a relatively high conductance of 17 nS. This is close to the conductance between Qi/Qo feedback - drain/source. Strongly suspect that this is a short. Could this be a reason for the noisy baseline seen in Qi on side 2 during Run 31? Such a short was not present when conducting the electrical checks at 4.2 K last run, but perhaps it developed over time… like our leak! Will keep an eye on it once we reach base temperature.
Detector: G103a DIB1 BH: Stripline: 19
SC: ZB1-1-6 300 K 80K LHe
Face: 2 Date 2012-09-27 Date 2012-09-29 Date 2012-09-30
SQUET: ZC23 Who RR Who HC Who HC
Signal Pos. lead Gnd lead Nominal Actual Chassis Nominal Actual Chassis Nominal Actual Chassis
(Gnd lead) (Gnd lead) (Gnd lead)
Nominal: Nominal: Nominal:
< 0.1 nS < 0.1 nS < 0.1 nS
Phonon
SQUID bias A/Ret 4 20 3 - 5 k 4.4 OK 1 - 2 k 1.7 OK 80 - 140 107 OK
SQUID bias B/Ret 19 34 5 OK 2 OK 80 - 140 >150 (charges like a capacitor) OK
SQUID bias C/Ret 8 24 4.6 OK 1.8 OK 80 - 140 104 OK
SQUID bias D/Ret 23 39 4.3 OK 1.6 OK 80 - 140 94 OK
Feedback A/Ret 37 21 15 - 25 k 18 OK 9 - 13 k 7.4 OK 1.0 - 1.3 k 1.26k OK
Feedback B/Ret 2 18 20 OK 8.4 OK 1.0 - 1.3 k 1.27k OK
Feedback C/Ret 41 25 19 OK 7.7 OK 1.0 - 1.3 k 1.25k OK
Feedback D/Ret 22 6 18 OK 7.2 OK 1.0 - 1.3 k 1.25k OK
QET A/Ret 3 1, 13, 14, 17, 32 60 - 80 126, 114, 97,100, 98 OK 30 - 40 84,75,57,60,58 OK 20 - 30 72,60,42,46,43 OK
QET B/Ret 35 29, 33, 47, 48 90, 89, 138, 89 OK 50,49,64,50 OK 20 - 30 36,35,50,35 OK
QET C/Ret 7 5, 9, 10, 28 97, 85, 74, 84 OK 58,46,36,45 OK 20 - 30 40,33,22,32 OK
QET D/Ret 38 36, 40, 43, 44 99,85, 85, 85 OK 59,47,47,47 OK 20 - 30 47,34,33,33 OK
Charge
FET heater +/- 45 46 1.0 - 1.1 k 1.068 OK 1.0 - 1.1 k 1.045 OK 1.0 - 1.1 k 1.2k OK
Qi bias/QET Ret 15 24 - 26 nS 26 OK < 1 nS 26 OK <1 nS 11 OK
Qo bias/QET Ret 11 26 OK 26 OK <1 nS OK OK
Qi feedback/Drain/Source 50 16, 31 15 - 17 nS 23 OK 6 - 8 nS 21,21 OK <1 nS 19,19 OK
Qo feedback/Drain/Source 30 12, 27 23 OK 21,.21 OK <1 nS 19,19 OK
Qi drain 16 chassis < 0.1 nS – OK < 0.1 nS – OK <0.1 nS – OK
Qo drain 12 chassis – OK – OK <0.1 nS – OK
Qi source 31 chassis – OK – OK <0.1 nS – OK
Qo source 27 chassis – OK – OK <0.1 nS – OK
FET Tsense +/FET heater- 49 46 0.6 - 0.7 V 0.729 OK 0.9 - 1.0 V 1.094 OK — – OK
LED 1 chassis 42 1.0 - 1.1 V open – 1.2 - 1.5 V open – — – –
LED 2 chassis 26 1.11 – 1.38 – — – –
Detector: G103a DIB2 BH: Stripline: 20
SC: ZB1-1-9 300 K LN LHe
Face: 5 Date 2012-09-27 Date 2012-09-29 Date 2012-09-30
SQUET: ZC28 Who RR Who HC Who HC
Signal Pos. lead Gnd lead Nominal Actual Chassis Nominal Actual Chassis Nominal Actual Chassis
(Gnd lead) (Gnd lead) (Gnd lead)
Nominal: Nominal: Nominal:
< 0.1 nS < 0.1 nS < 0.1 nS
Phonon
SQUID bias A/Ret 4 20 3 - 5 k 4k OK 1 - 2 k 1.6k OK 80 - 140 115 OK
SQUID bias B/Ret 19 34 4.2k OK 1.6k OK 80 - 140 94 OK
SQUID bias C/Ret 8 24 4.8k OK 1.9k OK 80 - 140 102 OK
SQUID bias D/Ret 23 39 4.2k OK 1.6k OK 80 - 140 88 OK
Feedback A/Ret 37 21 15 - 25 k 23.5k OK 9 - 13 k 8.6k OK 1.0 - 1.3 k 1.25k OK
Feedback B/Ret 2 18 17.4k OK 7.3k OK 1.0 - 1.3 k 1.27k OK
Feedback C/Ret 41 25 20.7k OK 8.7k OK 1.0 - 1.3 k 1.43k OK
Feedback D/Ret 22 6 18.3k OK 7.3k OK 1.0 - 1.3 k 1.25k OK
QET A/Ret 3 1, 13, 14, 17, 32 60 - 80 114, 103, 86, 89, 86 OK 30 - 40 76,66,48,51,49 OK 20 - 30 62,51,34,37,35 OK
QET B/Ret 35 29, 33, 47, 48 74, 73, 99, 74 OK 41,40,54,40 OK 20 - 30 29,28,42,28 OK
QET C/Ret 7 5, 9, 10, 28 84, 72, 64, 71 OK 49,37,30,37 OK 20 - 30 35,24,16,23 OK
QET D/Ret 38 36, 40, 43, 44 85, 72, 71, 72 OK 51,39,38,39 OK 20 - 30 39,27,26,27 OK
Charge
FET heater +/- 45 46 1.0 - 1.1 k 1.06k OK 1.0 - 1.1 k 1.052k OK 1.0 - 1.1 k 1.2k OK
Qi bias/QET Ret 15 24 - 26 nS 26 OK < 1 nS 26 OK <1 nS 17 OK
Qo bias/QET Ret 11 25 OK 25 OK <1 nS 5 OK
Qi feedback/Drain/Source 50 16, 31 15 - 17 nS 23 OK 6 - 8 nS 21,21 OK <1 nS 18,18 OK
Qo feedback/Drain/Source 30 12, 27 23 OK 20,20 OK <1 nS 19,19 OK
Qi drain 16 chassis < 0.1 nS – OK < 0.1 nS – OK <0.1 nS – OK
Qo drain 12 chassis – OK – OK <0.1 nS – OK
Qi source 31 chassis – OK – OK <0.1 nS – OK
Qo source 27 chassis – OK – OK <0.1 nS – OK
FET Tsense +/FET heater- 49 46 0.6 - 0.7 V .71 V OK 0.9 - 1.0 V 2.052 OK — – OK
LED 1 chassis 42 1.0 - 1.1 V 1.12 V – 1.2 - 1.5 V 1.39 – — – –
LED 2 chassis 26 1.11 V – 1.38 – — – –
Detector: G103a DIB3 BH: Stripline: 21
SC: ZB1-1-11 300 K LN LHe
Face: 6 Date 2012-09-27 Date 2012-09-29 Date 2012-09-30
SQUET: ZC70 Who RR Who HC Who HC
Signal Pos. lead Gnd lead Nominal Actual Chassis Nominal Actual Chassis Nominal Actual Chassis
(Gnd lead) (Gnd lead) (Gnd lead)
Nominal: Nominal: Nominal:
< 0.1 nS < 0.1 nS < 0.1 nS
Phonon
SQUID bias A/Ret 4 20 3 - 5 k 4.8k OK 1 - 2 k 2k OK 80 - 140 101 OK
SQUID bias B/Ret 19 34 4.4k OK 1.7k OK 80 - 140 113 OK
SQUID bias C/Ret 8 24 4.6k OK 1.8k OK 80 - 140 99 OK
SQUID bias D/Ret 23 39 5.2k OK 2.1k OK 80 - 140 97 OK
Feedback A/Ret 37 21 15 - 25 k 29k OK 9 - 13 k 15.1k OK 1.0 - 1.3 k 1.25k OK
Feedback B/Ret 2 18 25k OK 9.4k OK 1.0 - 1.3 k 1.27k OK
Feedback C/Ret 41 25 28k OK 14.3k OK 1.0 - 1.3 k 1.25k OK
Feedback D/Ret 22 6 34k OK 17.6k OK 1.0 - 1.3 k 1.24k OK
QET A/Ret 3 1, 13, 14, 17, 32 60 - 80 125, 115, 98, 102, 99 OK 30 - 40 85,76,59,62,60 OK 20 - 30 64,55,37,40,38 OK
QET B/Ret 35 29, 33, 47, 48 86, 85, 101, 85 OK 45,44,59,44 OK 20 - 30 30,30,44,30 OK
QET C/Ret 7 5, 9, 10, 28 96, 84, 76, 84 OK 57,46,37,45 OK 20 - 30 38,27,18,26 OK
QET D/Ret 38 36, 40, 43, 44 100, 88, 87, 87 OK 60,49,48,48 OK 20 - 30 41,28,28,28 OK
Charge
FET heater +/- 45 46 1.0 - 1.1 k 1.065k OK 1.0 - 1.1 k 1.043k OK 1.0 - 1.1 k 1.2k OK
Qi bias/QET Ret 15 24 - 26 nS open OK < 1 nS open OK <1 nS open OK
Qo bias/QET Ret 11 open OK open OK <1 nS open OK
Qi feedback/Drain/Source 50 16, 31 15 - 17 nS 23 OK 6 - 8 nS 20,20 OK <1 nS 18,18 OK
Qo feedback/Drain/Source 30 12, 27 23 OK 20,20 OK <1 nS 19,19 OK
Qi drain 16 chassis < 0.1 nS – OK < 0.1 nS – OK <0.1 nS – OK
Qo drain 12 chassis – OK – OK <0.1 nS – OK
Qi source 31 chassis – OK – OK <0.1 nS – OK
Qo source 27 chassis – OK – OK <0.1 nS – OK
FET Tsense +/FET heater- 49 46 0.6 - 0.7 V OPEN OK 0.9 - 1.0 V 1.087 OK — – OK
LED 1 chassis 42 1.0 - 1.1 V 1.11V – 1.2 - 1.5 V 1.39 – — – –
LED 2 chassis 26 OPEN – open – — – –
2235 Interrupt cryocleaning and pump mixture into dump in preparation for condensation.
2340 Pressure in dump 727 mbar. Isolate IVC and start 1 K pot, temperature 1.78 K.
2345 Mixing chamber temperature 7.3 K. Start condensing mixture manually through nitrogen cold trap 1.