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Entry  Fri Dec 13 01:51:15 2019, Raymond, DailyProgress, PD QE, Cryostat wiring fixes 18_32malepinsinairAssigned.pdf
    Reply  Mon Dec 16 18:16:31 2019, Raymond, DailyProgress, PD QE, Cryostat wiring fixes 
Message ID: 2479     Entry time: Fri Dec 13 01:51:15 2019     Reply to this: 2480
Author: Raymond 
Type: DailyProgress 
Category: PD QE 
Subject: Cryostat wiring fixes 
  • Monitored an autorun of the photocurrent for A2P6 from about 77K-300K and adjusted the laser alignment as necessary. I've not yet looked through the data, as I was keen on fixing the assorted wiring issues in time to pump down for tomorrow. Chris found the laser power issue rooted in my sub-optimal diode-collimator mating connection, ie I didn't fully plug back in the laser. I've learned my lesson and will simply shield the fiber with Al foil for future nitrogen pouring endeavours .
  • Opened the cryostat and confirmed the pin assignments (see attached list).
  • Cathode 2 was shorting on the thermal anchors for the PD plug. I re-wrapped the quad twist wire around the bobbins and this has fixed the issue, though I did not see any portion of the quad twist wires that was missing the Formvar insulation. 
  • The DT-670 silicon diode thermometer was busted, this was likely the case from the start and should have been checked (by me) prior to wiring. I've replaced this diode with another 4-lead platinum resistor, it is plugged into input 3 on the CTC100 (still labeled 'PDdiode'). 
  • The thermistor on A2P6 is still intact, showing about 1.9 kΩ at room temp

Still to do:

  • Move the radiation shield PT RTD to the outer shield
  • Re-wire the baseplate pins in the DSUB9 connection to the CTC100 temp controller (switched V+ and V-)
  • Check feasibility of adding 25Ω heater to the sample mount to stabilize the temp of the PD rather than measuring while sweeping 


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