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Thu Aug 5 09:20:44 2021, Aidan, Laser, 2um Photodiodes, Optical design for 2um PD in new cryo chamber
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Thu Aug 5 12:39:56 2021, Aidan, Laser, 2um Photodiodes, Optical design for 2um PD in new cryo chamber
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Thu Aug 5 14:29:42 2021, Stephen, Laser, 2um Photodiodes, Optical design for 2um PD in new cryo chamber   
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Tue Aug 24 15:01:25 2021, Stephen, Laser, 2um Photodiodes, 2um PD in new cryo chamber
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Thu Aug 26 14:31:46 2021, Aidan, Stephen, Laser, 2um Photodiodes, Incident power calibration of 2um PD in new cryo chamber 
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Fri Aug 27 17:57:30 2021, Stephen, DailyProgress, 2um Photodiodes, Start of PD pumpdown
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Sat Aug 28 07:01:21 2021, Aidan, DailyProgress, 2um Photodiodes, Start of PD pumpdown 
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Sun Aug 29 11:17:43 2021, Aidan, DailyProgress, 2um Photodiodes, Start of PD pumpdown 
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Mon Aug 30 08:04:52 2021, Aidan, DailyProgress, 2um Photodiodes, Monday morning observation of JPL A1 PD cool down
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Message ID: 2656
Entry time: Sun Aug 29 11:17:43 2021
In reply to: 2655
Reply to this: 2657
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Author: |
Aidan |
Type: |
DailyProgress |
Category: |
2um Photodiodes |
Subject: |
Start of PD pumpdown |
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Sunday morning update:
11:17AM - Temperature of photodiode is ~86K
Also shown is the photodiode current time series. The laser is being ramped from minimum to maximum every 50s. The span of the signal increases as temperature is decreased. The response is almost nil at room temperature. Then it peaks around 140K and is clearly reduced by the time we get below 100K. (Caveat: the beam was initially aligned onto the PD at room temperature but there is currently no auto-alignment. The diode is quite large, 1.5mm sq, but we can;t rule out that the beam is moving off the PD as temperature decreases - so we can only put an lower limit on QE vs temperature from this data). |
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