Table of Contents
2010/08/16
Run Diary
| 0943 | Fill N2 cold trap full |
|---|---|
| 0947 | Isolate pumping station, IVC He: 1.7E-7 cc/s, pressure: 1.6E-6 mbar, MC X12004 = 8.9K. Close IVC |
| 1000 | Start 1K pot, start condensing |
| 1007 | ILM was left on fast rate, it burned a bit of helium |
| 1209 | Add 5mW to still, Tower T=0.46K |
| 1240 | Tower T ~450mK, MC T~80mK, cool down the tower is really slow |
| 1633 | Turn still heater off, tower T = 48.1 mK |
| 1657 | Power on DCRC v1, tower T=49.4 mK |
| 1704 | Turn on charge channels |
| 1707 | Zap SQUIDs |
| A and D still have flux trapped, zap SQUIDs a few more times | |
| Tried Ic measurement by sending a triangle wave down the QET bias line |
| IbIs resistance values | ||
|---|---|---|
| Channel | Rn (Ohm) | Rp (mOhm) |
| A2 | 1.25 | 2.4 |
| B2 | 1.33 | -2.9 |
| C2 | 0.36 | 0.2 |
| D2 | 1.26 | -0.1 |
| IbIs Plots |
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| Tc measurement | ||
|---|---|---|
| Channel | Tc (mK) | Average (mK) |
| A2 | 76, 85, 88, 83, 87 | 84 |
| B2 | 100,106, 101, 104.5, 107 | 104 |
| C2 | 89, 93, 90, 91, 92, 90, 92, 97, 90, 97.5 | 92 |
| D2 | 85, 92, 84, 88, 89, 92 | 88 |
Ic measurement
| Measure Ic as a function of temperature. Two methods are used to measure Ic: 1) is to send a sin wave down the QET bias line and increase the bias gradually and record the feedback output from DCRC or the scope when the output start to distort; 2) is to excite the TES sensor with a large triangle wave and measure the voltage range of the superconducting part. Both methods show jumping signals near the transition. Method 2) is not easy to measure and average may also bring in systematic errors. I thinks Method 1) is more likely to get consistent results. Below I post the results from the above measurements |
Method 1
| Ic at 50mK | ||||
|---|---|---|---|---|
| Channel | HP3325A (mVpp) | Feedback output (V) | Ic (uA) | Comment |
| A2 | 104 | 1.15 | 57.5 | DCRC |
| B2 | 240 | 3.04 | 152 | TPS2024 |
| C2 | 298 | 3.60 | 180 | TPS2024, when the setting of HP3325A is larger than a given value, all output disappeared, not sure this is the real Ic |
| D2 | 136 | 2.03 | 101.5 | DCRC |
| Ic at 80mK | ||||
|---|---|---|---|---|
| Channel | HP3325A (mVpp) | Feedback output (V) | Ic (uA) | Comment |
| A2 | 120 | 0.92 | 46 | TPS2024 |
| B2 | 198 | 2.20 | 110 | TPS2024 |
| C2 | Temperature drifted when changing the bias. Did get the value | |||
| D2 | 140 | 1.50 | 75 | TPS2024 |
Method 2
In this method, 64 samples of output are averaged in the TPS2024 oscilloscope. Excitation: HP3325A 700mVpp sin wave.
| Ic at 80mK | ||
|---|---|---|
| Channel | Feedback output (V) | Ic (uA) |
| A2 | 0.68 | 34 |
| B2 | 1.52 | 76 |
| C2 | 2.60 | 130 |
| D2 | 0.84 | 42 |
| Ic at 65mK | ||
|---|---|---|
| Channel | Feedback output (V) | Ic (uA) |
| A2 | 0.84 | 42 |
| B2 | 2.32 | 116 |
| C2 | 4.40 | 220 |
| D2 | 1.52 | 76 |