2015/05/13 (Wednesday)
| 0900 | Fill LN trap Dewar |
|---|---|
| 0900 | MC/Tower = 53/75 mK. G1/G2 = 292/258 mbar. Still = 4 mW / 1.11 K / 0.19 mbar. 1K Pot = 1.73 K / 22 mbar. Coldplate = 9.46 kΩ / 307 mK. MC sensor = -38.47 kΩ / 67 mK. |
| 0905 | Turned the DIB1 FETs back on. The interference problem did not occur until the afternoon, when biases were applied to the crystal during daq tests. It seems that at 0V there is no problem with running the DIB1 FETs. |
| 1635 | Start LHe transfer (28.8%). |
| 1640 | Perform successful MIDAS flashing loop. |
| 1735 | End LHe transfer (91.0%). |
| 1750 | Forgot to change temperature sensor on labview program. Thus, change labview program to mixing chamber temperature now. |
| 1800 | Commence IbIs measurements on DIB2 (Stripline 27) with DCRC 50. |
| Fill LN2 cold trap full. |
Used the IbIs measurements to calculate optimal QET bias currents using the following method:
- Fit a line to the normal-resistance portion of the curve (high bias) and extend to Ib=0
- Construct a second line with the same Ib=0 intercept as the previous but with slope 4 times greater
- Where the second line intersects with the IbIs curve, use this Ib value as optimal QET bias current
Also shown in the table below are the critical currents as read off of the IbIs curves: the Ib value at which the curve abruptly changes to superconducting behavior.
For the IbIs measurements using DCRC33, a range of -400 μA to 0 μA was used. However this was not a wide enough range to see the linear normal-resisting part of the curve for most of the phonon channels. Only those shown below produced reliable results:
| Optimal QET bias currents using DCRC33 | |||
|---|---|---|---|
| DIB | QET | Optimal bias (μA) | Critical current (μA) |
| 1 | A | -133 | |
| 1 | B | -139 | |
| 1 | C | -126 | |
| 1 | D | -127 | |
| 2 | A | -106 | |
| 2 | B | -80 | |
| 2 | C | -125 | |
| 2 | D | -123 | |
| 3 | A | -125 | -97 |
| 3 | B | -129 | |
| 3 | C | -121 | |
| 3 | D | -124 | -95 |