Table of Contents
2010/02/22
| Time | |
|---|---|
| 15:50 | Zero DCRC according to the calibration table, zapping all SQUIDS. |
| 16:03 | Zapping all SQUIDS again. |
| 16:18 | Turn on test signal slope = 43, mag.=17606, tune SQUID. |
| Turn off test signal, zap A again. | |
| Tune SQUIDs |
| SQUID settings | ||
|---|---|---|
| Channel | SQUID Bias (uA) | Lock point |
| A | 90 | 3.5 |
| B | 100 | 3.4 |
| C | 92.16 | 3.2 |
| D | 95 | 3.5 |
| SQUID modulation curves |
|---|
 |
| Closed loop settings | ||
|---|---|---|
| Channel | Frontend gain | Polarity |
| A | 3 | Non-inverting |
| B | 3 | Non-inverting |
| C | 3 | Non-inverting |
| D | 3 | Non-inverting |
| Closed loop response |
|---|
 |
| Time | |
|---|---|
| 17:44 | Save current settings as Preset 2. Need solder a pin on Feedback B, do it later. |
| 18:28 | Tower thermometer ~ 2min after MC at base T. MC temperature fluctuates. Set still power to 5mW |
| 18:37 | MC temperature fluctuates, Set still power to 7mW |
| 18:48 | MC temperature fluctuates, Set still power to 8mW |
| 19:07 | MC temperature fluctuates, Set still power to 0mW |
| 19:34 | MC temperature drops to 26mK |
| 19:59 | MC temperature stays at 25.9mK |
| Measure Ic as a function of temperature. Didn't get meaningful data because temperature fluctuation. | |
| Measure Tc. | |
| 22:00 | Fill N2 cold trap full |
Ic vs T
Ic in the table below is the function generator output, or the input to the QET bias line.
| MC T (mK) | Tower T (mK) | Ic (mVpp) | MC heater (uW) | |
|---|---|---|---|---|
| phA | phD | |||
| 25.7 | 124.15 kΩ | 91 | 196 | 0 |
Tc
Send 1mVpp 100Hz triangle signal, apply different power to the mixing chamber, and watch at which resistance (temperature) the triangle wave disappear or reappear.
| MC power (uW) | 50 | 0 | 20 | 0 | 10 | 0 | 10 | 6 | 5 |
|---|---|---|---|---|---|---|---|---|---|
| Temperature change | ↑ | ↓ | ↑ | ↓ | ↑ | ↓ | ↑ | ↑ | ↓ |
| phA (kΩ) | missed | 26.96 | 31.6 | 26.9 | 29.6 | 27.67 | 28.8 | 29.4 | 28 |
| phA (mK) | missed | 81.3 | 73.8 | 81.4 | 76.7 | 80.0 | 78.0 | 77.0 | 79.4 |
| phD (kΩ) | missed | 26.75 | 30.8 | 26.4 | 28.8 | 27.6 | 28.1 | 28.5 | 27.7 |
| phD (mK) | missed | 81.7 | 74.9 | 82.4 | 78.0 | 80.1 | 79.2 | 78.5 | 79.9 |
From the above table, Tc of A is between 75mK and 80mK and Tc of D is between 80mK and 85mK. Numbers from CWRU