enter Thu Mar 11 13:56:46 2021

• On Busby low noise box AC coupled input (logged by to 1 MOhm moku channel 2)
  • measure voltage noise of a 20.5 Ohm resistor for 28 minutes
  • measure voltage noise across the same resistor in driven by ITC502 at 119.38 mA, same duration
  • python [path/to/moku]mokuDataLogger.py -c ch2 -i 10.0.5.253 -d 1680 -s 64e3 --useInternal --fileType bin --MOhmr2
  • started to make a box for sensing current noise... but perhaps this is not necessary. To measure 10 kHz/rtHz frequency noise on our 147 MHz/mA diode (-> uV/rtHz), even the metal film resistors (1% tol) with the steepest temperature coefficients on digikey (~100 ppm/K) could allow 10 mK/rtHz temperature fluctuations of the resistor. Still, the room is drafty, so I also measured the noise across the resistor driven by two AAA batteries (2.4 V total, for about the same current as before).
  • What is the voltage across the diode during operation, and can I check this at some of the butterfly pins? Does the current supply remain consistent operating at the same current but a different voltage? And, shouldn't a 'low noise current supply' be quieter than a battery (at least at the frequencies where it matters) anyway?
• While waiting for the data, assembled the wire shelf on the West wall of PSOMA, between the vacuum cabinet and He cryostat.
  • Electronics on the 2nd shelf have rails for earthquake protection. We have sufficient rails for all 4 shelves, but I left them for another day.
  • Zip-tied the upper shelves to the piping on the wall. Seems sturdy.
  • Feet have plastic sliders to dampen the load on the floor. We also have label holders in need of labeling.
  • Photos are in the ligo.wbridge google drive and some attached.

exit Thu Mar 11 23:11:33 2021