2022/12/16 (Friday)
- Lab in-personnel: Matt, Himangshu
| Status | Run 76 finished |
|---|---|
| Setup | DCRC33(2)→HV control, NaI trigger signal → DCRCX(4) |
| IVC open. Mixture in dump. Warm LN2 Trap 1 clean. Clean tent erected at bottom of fridge. Deinstallation started, 4K, 600mK, 100mK stages removed yesterday. | |
| 1505 | Electrical check at base of tower, triple-checking the source mover motor coils which started reading open after the third attempted move (months ago). All still read open. |
| Finish removing tower: | |
| 1510 | Unplug Goldman thermometer. NOTE: both the Goldman thermometer and the Tower thermometer read incorrectly when using the fridge thermometer wire. We should try replacing the connector, maybe something wrong with it. |
| 1520 | Remove all but 4 screws attaching tower to MC can, and remove spool cap from bottom of tower |
| 1530 | Attach fridge stand ring to IVC (careful not to scratch bottom surface with screws), raise fridge stand to support tower and insert threaded rods. Remove remaining tower adapter screws so tower is supported by fridge stand. Place scissor jack on red drill case and extend it to support tower stand |
| 1540 | Detach threaded rods from fridge stand. Lower tower with scissor jack being careful not to snag wires, 600mK rod, striplines. Collapse scissor jack lowering tower as far as the threaded rods can reach, then reattach threaded rods to support tower. Then remove red case and extend jack to support stand. Remove threaded rods. |
| 1550 | Continue lowering tower till jack is at minimum height. Detach ring from IVC, lower ring to bottom of tower stand rods (careful to lower it level, so it doesn't get stuck on rods). Pull tower stand on scissor jack out from beneath fridge, pulling rods apart enough to clear IVC. Double-bag tower on tower stand and carry stand with tower into cleanroom anteroom. |
| Begin tower disassembly and post-mortem: | |
| 1610 | Remove threaded rods from stack. Remove stack lid along with Goldman thermometer. (We were able to slide the wires out of the adapter ring without disassembling it.) |
| 1615 | Remove kapton tape holding down the source mover wires. Disconnect source mover plugs from tower sockets. |
| 1620 | Check resistances at source mover stripline pins - motor coils all show continuity! Check continuity of Tower Face 6 wires - 1-4 and 6-9 all read open. Apparently the source mover driver fried these tower wires! Other Face6 wires are fine, 27 Ohms each. |
| Link to the paper that describes the tower design, including the tower wires | |
| 1625 | Remove source mover without turning it rightside up. Hold over a camera to photograph the source position. (Not 100% sure that it didn't shift during deinstallation.) |
| 1625 | Notice some grit on detector surface. Remove some of it carefully with small piece of wipe dampened with methanol. |
| 1630 | Remove cover plate from 4K stage (bottom) of Tower Face6. Can see a couple of the wires are broken. |
