2010/10/16
| 2130 | Weird - stripline 20 has started working… |
|---|---|
| Why? | |
| 2230 | Can't come up with plausible explanation, so best to open it and take a look |
| We have had problems like this that just fix themselves in the past | |
| Stop pumping IVC at 3E-5 mbar | |
| Fill IVC with 1 bar N2 gas and open it | |
| 2330 | Quick electrical sanity check indicates same problem witnessed before - open QET A/Ret |
| 0130 | After some playing SQUET card ZC-15 seems to be responsible |
| It exhibits very temperamental behaviour - cable between card and SQUID works in one position and then stops working in another | |
| This would explain why it started working all of a sudden | |
| We've seen this before - it warrants further investigation | |
| SQUET card ZC-15 taken to clean room for electrical check | |
| 0400 | Bad news - QET bias A is open |
| … Well, this depends on the position of the cable | |
| It needs repair - placed on bottom shelf of purge cabinet in clean room |
SQUET card ZC-15 electrical check
| Signal | P1 | P4 | Acceptable Range [Ohms] | Measured |
|---|---|---|---|---|
| Feedback B | 14 to 1 | 15k to 25k | 19k | |
| QET bias A | 15 to 2,10,11,12,13 | 15 to 25 | open,open,open,open,open | |
| SQUID bias A | 16 to 3 | 2.5k to 4.5k | 5k | |
| Feedback D | 17 to 5 | 15k to 25k | 18k | |
| QET bias C | 18 to 4,7,8,9 | 15 to 25 | 20,20,20,20 | |
| SQUID bias C | 19 to 6 | 2.5k to 4.5 k | 4.2k | |
| QET bias B | 26 to 47,48,49,50 | 15 to 25 | 21,21,21,21 | |
| SQUID bias B | 27 to 39 | 2.5k to 4.5k | 4.5k | |
| Feedback A | 28 to 41 | 15k to 25k | 21k | |
| QET bias D | 29 to 40,43,45,46 | 15 to 25 | 19,19,19,19 | |
| SQUID bias D | 30 to 42 | 2.5k to 4.5k | 4.1k | |
| Feedback C | 31 to 44 | 15k to 25k | 18k | |
| QET A | 1 to 2 | 10k to 25k | 15k | |
| QET B | 3 to 4 | 14k | ||
| QET C | 5 to 6 | 13k | ||
| QET D | 7 to 8 | 12k | ||
| LED 1 | 32 | 9 | <0.5 | 0.4 |
| LED 2 | 20 | 10 | <0.5 | 0.4 |
| Qo bias | 21 | 11 | <0.5 | 0.5 |
| Qo feedback | 23 | 13 | <0.5 | 0.5 |
| Qi bias | 24 | 14 | <0.5 | 0.4 |
| FET heater +/- | 34 to 35 | 980 to 1020 | 1014 | |
| Qi feedback | 38 | 16 | <0.5 | 0.4 |
| FET Temp+ | 37(+) to 35(-) | 4M to 5M | 11M | |
| Qo drain | 22(-) | 12(+) | 5M to 7M | 11M |
| Qo source | 33(-) | 12(+) | 5M to 7M | 11M |
| Qi source | 36(-) | 15(+) | 5M to 7M | 11M |
| Qi drain | 25(-) | 15(+) | 5M to 7M | 11M |
| SQUID Isolation Checks | ||||
| A FB-QETbias | 28 to 16 | 100M to inf | OK | |
| A FB-SQUIDbias | 29 to 15 | 100M to inf | OK | |
| A Qetbias-SQUIDbias | 15 to 16 | 100M to inf | OK | |
| B FB-QETbias | 28 to 16 | 100M to inf | OK | |
| B FB-SQUIDbias | 29 to 15 | 100M to inf | OK | |
| B Qetbias-SQUIDbias | 15 to 16 | 100M to inf | OK | |
| C FB-QETbias | 28 to 16 | 100M to inf | OK | |
| C FB-SQUIDbias | 29 to 15 | 100M to inf | OK | |
| C Qetbias-SQUIDbias | 15 to 16 | 100M to inf | OK | |
| D FB-QETbias | 28 to 16 | 100M to inf | OK | |
| D FB-SQUIDbias | 29 to 15 | 100M to inf | OK | |
| D Qetbias-SQUIDbias | 15 to 16 | 100M to inf | OK | |