2016/09/01 (Thor's day aka Day Ruined SQUID)
| 0847 | The tower is still in the fridge. Looks like its new weight can be supported! |
|---|---|
| 1029 | Turned 3He pump on, opening v9 to the dump. Currently P1=0.95mbar, G1=3.7mbar, Dump=767 mbar. |
| 1030 | Opening v6. |
| 1031 | Once P1 started to drop, opened gate valve to pump on still side fridge lines. |
| 1033 | Fill LN2 cold trap full. |
| 1100 | Installed heat sinks and SQUET cards. |
| 1145 | Performing electrical check at breakout box. All measurements look good except we're unable to see any of the UV LED Vforward. |
| 1303 | Remove SQUET card and measure Vforward =0.78V by measuring Pins 3 and 5 on tower to chassis. |
| 1433 | After much bafflement, find that some SQUET cards (e.g. ZC-13, ZC-26) seem to have QET bias/return lines reversed from what's expected/assumed in our wiring tables/DIB diagrams and detector checkout sheets! This was done by measuring resistance through SQUET card e.g. from pins 47-50 on the stripline side (QETB returns) to Pins 3-4 on tower side (3 is expected to be QETB returns). This should be further investigated. (Which SQUETs are which way? Have we been using our QETs backwards?) |
| SQUET | ZC-13 | ||||
|---|---|---|---|---|---|
| Stripline Pin | Stripline Signal | Detector Pin | Detector Signal | Resistance | Comments |
| 47-50 | QETB ret | 2 | QETA | open | |
| 47-50 | QETB ret | 3 | QETB ret | 14kΩ | Actually measuring feedback coil? |
| 47-50 | QETB ret | 4 | QETB | 21Ω | Actually measuring QETreturn line (should go straight through) |
| 4,7-9 | QETC ret | 4 | QETB | open | |
| 4,7-9 | QETC ret | 5 | QETC ret | 18kΩ | feedback coil? |
| 4,7-9 | QETC ret | 6 | QETC | 23Ω | QET return? |
| SQUET ZC-87 has similar values, but with the values for detector pins 3 and 4 reversed and for pins 5,6 reversed from the above. |
| 1440 | Replacing with two SQUETs from ante-room which have the expected wiring as follows: ZC-87/ZC-68 = North/South SQUET = Stripline 27/20 . |
|---|---|
| 1500 | Perform electrical check. Stripline 27: FeedbackC,FeedbackC ret, SQUID C, SQUIDC ret all have 8MΩ shorts to chassis. This does not affect the current detector. |
| 1645 | Attach lower flange of IVC and begin tightening. |
| 1710 | Commence pumping out IVC with scroll pump. |
| 1730 | Close V6, open V1, V5 and condenser line speedivalve to begin pumping fridge from that side (including more directly pumping out He cold trap. |
| 1750 | IVC pressure reached 8.6e-2 mbar, switch to turbo pump to continue pumping down IVC. |
| 1755 | Fill LN2 cold trap full. With G1/G2=1 mbar / 778 mbar, P1=15 ubar, start closing gate and condenser line valves, and V1 and V5 to isolate the fridge lines. |
| 1805 | Close V9 and turn off He3 pump (G2=778 mbar). |
| 1815 | Take down clean tent. With IVC pressure at 1.4e-3 mbar, leave IVC pumping out overnight. |