2019/09/19 (Thursday)
| Status: Tower installed yesterday, preparing for Run 71. Some connection problems probably at SQUET ZC-74. Have cryocleaned mixture 11 times so far. | |
| yesterdayd: During electrical check of DIB3 find that SQUID B is open and QETB is not connected (QETB return lines are OK). Suspect the SQUET, ZC-74. Pin 27 on the stripline side has been trouble, we tried resoldering it. Pin 26 is QETB, right next to it. This one was unstable when we unplugged the SQUET from the tower and messed with it. We'll remove the SQUET and try to repair it. | |
| 0915 | At breakout box short the SQUID B leads for DIB3, then check continuity at the stripline connector pins on the cold end. Shows continuity. Do the same with QET B, also shows continuity. So as expected no problem with the stripline. Need to repair SQUET ZC-74. |
| 1221 | Electrical check on DIB2 showed an open FET Tsense. Doesn't seem to improve with cable wiggling. Not sure if this is important for charge channels, but let's move this card to DIB3, which has no charge, just to be safe. Moved SQUET ZC-70 to DIB3. Updated electrical checkout sheets. |
| 1515 | Finish repairing SQUET ZC-74. Four pins in a row on the stripline side seem to have trouble connecting to the middle PCB layer: 26,27,28,29. For 26 and 28 messing with them with the soldering iron seemed to fix them. For 27 and 29 I wound up soldering an extra wire on the outside of the board from the pin to the connection to the SQUID board. One of the soldered wires is for SQUID Bias B. The other is for QET D on the detector side (so this is in series with the QET).  |
| 1525 | Check warm LN2 Cold Trap 2: 3.4 mbar. Pump out trap. |
| 1635 | ZC-74 had more problems, wound up soldering on 2 more wires, stripline-side Pin 15 for QET A on detector side, and stripline-side Pin 26 for QET B on detector side. |
| Channels with wire jumpers in series with QET: DIB2 pA/B/D = Side2pC / Side2pA / Side1pA. Channel with jumper to SQUET bias: DIB2pB = Side2pA |
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| 1700 | Electrical checkouts look OK. Start closing IVC. |
| 1720 | IVC screws mostly tightened. Start pumping out IVC with scroll pump |
| 1730 | Scroll pumping pressure on IVC = 340 ubar |
| 1735 | Put both LN2 cold traps into bath and fill bath. Open V9, V13a, and V13b to leave mixture open to traps overnight for passive cleaning. (Leaving 3He pump off.) Also open V4, V12a+speedi, V12b+speedi to open mix to both sides of traps. |
| 1740 | Scroll pumping pressure on IVC = 160 ubar Remembered to close both the valve to the manual gauge on the turbo station and the valve to the check valve at the top of the fridge. |
| 1754 | Switch over to turbo pump. Pumping pressure in IVC = 7.4 ubar |