2016/01/22 (Friday)
| Setup: iZIP mode, DIB1/2/3 → cables → 3.2 MHz filters → DCRC55/33/50 | |
| Cf activation overnight. | |
| 0830 | Tower/MC(H35)/MC sensor/Cold Plate = 31.3/27.3/39/150 mK, Still = 1.12 K / 0.12 mbar, G1/G2 = 150/125 mbar, 1K Pot = 1.73 K / 19 mbar, Main bath = 33.8% |
| 0835 | Fill LN2 cold trap Dewar. |
| 1015 | Begin disassembling North wall of fridge shield. Intent is to remove poly from middle to allow path for photoneutrons |
| 1040 | Remove Cf source from fridge |
| 1100 | Remove all poly from north wall of shield, then replace four partial pieces (each 1“ thick) leaving a hole in the middle for the photoneutrons. See photo: |
| 1200 | Replace lead shield on north wall of shield. |
|---|---|
| 1410 | Measure raw event rate by observing phonon traces. Count 78 events in 1 second, 78 Hz. |
| 1415 | Check phonon channels, a couple of relocks then all look OK. |
| 1416 | Start 1 hour (1 series) of 30min background series at -4/+4V with FG=5/2/5, OG=3, with 1000 initial randoms, 1000 ending randoms, 30s flash and 25 minute cooldown before series. Trigger on DIB1 phA with threshold of 30ADC bins. |
| 1520 | Main bath = 22.0% |
| 1525 | Start LHe transfer at 21.5% |
| 1616 | End transfer at 90.7% |
| 1630 | Place photoneutron source holder on fridge. End of source rod is about 116 cm down from top edge of main bath flange |
| 1635 | Observe a little low-freq noise in DIB2pD. Release pressure from top of cryostat. |
| 1645 | Place Be disk in source box and two layers of lead bricks for 4” of lead shielding between source and fridge shield |
| 1700 | Fill LN2 cold trap |
|---|---|
| 1705 | Attach strong Y-88 source to source holder box |
| Strong low-freq noise, try letting pressure out again | |
| Count 50 events in 0.5 seconds, rate about 100 Hz | |
| 1711 | Start 38 hours of 30min Y-Be photoneutron series at -4/+4V with FG=5/2/5, OG=3, with 1000 initial randoms, 1000 ending randoms, 30s flash and 25 minute cooldown before series. Trigger on DIB1 phA with threshold of 30ADC bins. |