First dipping of the device at 4K in the Heliox
Check the level of Liquid Helium in the Fridge
- Open the dewar by turning the yellow part of 90 degrees
- Take the dipstick with the glove on top of it and dip it in the dewar
- When it vibrates, measure the distance between the top of the dipstick and the stop.
- Refer to the manual to find the level
- Note it on the Heliox dip sheet
- Remove the clamp on top of it
- Remove the top of the dewar
- Insert the lower part of the dipstick
- Put the clamp back in place
- Tighten the screw to hold the dipstick
- Slowly lower the dipstick, the little needle should make a whole turn every 4 seconds minimum on the gas board.
Use of the sensitive power supply : 100 micro Volts, 10 nA
4-6 : 1,5 nA
4-12 : 5,5 nA
4-13 : 5,5 nA
4-18 : 5 nA
4-16 : 0 nA
Remarks : Pin 16 Broken
Use of the AC Lock-in Amplifier : 20 nA (2V through a 100MOhm transformer), 17 Hz of current excitation in Pin 4
13 - 16 : 80 (In) 2 (Out)
12 - 8 : 55 (In) 1 (Out)
12 - 13 : 0 (In) 0 (Out)
8 - 16 : -145 (In) 0 (Out)
All results in micro Volts.
IVg - Characterisitc
Use of 2 Lock-in amplifiers synchronized : 500 micro Volts (voltage attenuator) 17 Hz excitation
Resonance at 4K
Graphics at Vg = 0V, I = 11,1nA
Problem : the resonance didn't change with the gate voltage -> problem with the inductor ?
- As a general rule I would not forward bias a Schottky gate too much. For holes this means don't go negative.
- The other inidcator of a problem with the inductor is that the resonance frequency is very different to that measured previously.
-- AlexHamilton - 26 Mar 2010