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Entry  Sun May 7 18:22:35 2017, rana, General, Voyager, Voyager ITM: Radiative cooling with cold shield and cold CP ITM-ColdShield-CP.png
    Reply  Sun Aug 26 19:21:27 2018, rana, General, Voyager, Voyager ITM: Radiative cooling with cold shield and cold CP ITM-Cooldown.pdfCoolDown.webm
Message ID: 130     Entry time: Sun Aug 26 19:21:27 2018     In reply to: 109
Author: rana 
Type: General 
Category: Voyager 
Subject: Voyager ITM: Radiative cooling with cold shield and cold CP 

this is a time dependent model of the previous steady-state one

  • Cold Shield and CP held at a constant 60 K
  • 3 W heat input to the ITM from the main laser beam
  • radiative cooling to the shield
  • ITM barrel emissivity = 0.9
  • ITM HR/AR emissivity = 0.5/0.5

So the cooldown time w/o a heat switch is ~4 days. Since this is less than the usual pumpdown time required to open the gate valves on the beamtubes, perhaps no heatswitch or in-vac cryogens are required.

Attachment 1: ITM-Cooldown.pdf  9 kB  Uploaded Sun Aug 26 21:10:09 2018  | Show | Show all
Attachment 2: CoolDown.webm  169 kB  Uploaded Sun Aug 26 21:16:14 2018
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