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Entry  Fri Jul 16 23:28:24 2021, Koji, Summary, Cryo vacuum chamber, Sus Test Work 07/16/2021 7x
    Reply  Sat Jul 17 00:55:41 2021, Koji, Summary, Cryo vacuum chamber, Temp Log 210716_2255 temp_log_cool_down_20210716_2255.pdf
       Reply  Mon Jul 19 15:57:17 2021, Stephen, Summary, Cryo vacuum chamber, Temp Log 210716_2255 
          Reply  Mon Jul 19 17:21:19 2021, Koji, Summary, Cryo vacuum chamber, Temp Log 210716_2255 temp_log_cool_down_20210716_2255.pdf
             Reply  Tue Jul 20 11:33:52 2021, Koji, Summary, Cryo vacuum chamber, A cooling model (Temp Log 210716_2255) cooling_model.pdfIMG_9390.JPGIMG_9391.JPG
                Reply  Tue Jul 20 17:28:30 2021, Koji, Summary, Cryo vacuum chamber, A cooling model (Temp Log 210716_2255) cooling_model.pdf
                   Reply  Wed Jul 21 21:05:59 2021, Koji, Summary, Cryo vacuum chamber, Test mass cooling (2021/07/16 ~ 2021/07/21) oplev_trend.png20210721201333_IMG_0765.jpeg20210716234113_IMG_0742.jpegScreenshot_from_2021-07-21_20-19-09.png
                      Reply  Thu Jul 22 22:03:45 2021, Koji, Summary, Cryo vacuum chamber, Test mass heating in progress (2021/07/21 ~ 2021/07/23) IMG-9395.jpgtemp_log_warmup_20210721_2052.pdf
                      Reply  Sun Jul 25 21:45:46 2021, Koji, Summary, Cryo vacuum chamber, About the radiation heat transfer model 
Message ID: 2610     Entry time: Tue Jul 20 11:33:52 2021     In reply to: 2609     Reply to this: 2611  
Author: Koji 
Type: Summary 
Category: Cryo vacuum chamber 
Subject: A cooling model (Temp Log 210716_2255) 

A naive cooling model was applied to the cooling curve.
A wild guess:

- The table temp is the same as the test piece temp as measured on 2021/7/9
- The inner shield temp is well represented by the table temp
- The specific heat of Si is almost constant (0.71 [J/(g K)] between 300K~200K

Radiative cooling:
The curve was hand-fitted by changing the emissivity of the inner shield and the silicon mass. I ended up having the same values for these to be 0.15.
Surprisingly well fitted!

Conductive cooling:
The conductive cooling through the wire does not fit the cooling curve, although the quantitative evaluation of the wire conductivity needs to be checked carefully.

Appendix:
Stephen shared attachments 2 and 3, which contain insights on the wire used to hang the Si mass. .017" diameter Music Wire from California Fine Wire, 2004 vintage, borrowed from Downs High Bay.

Attachment 1: cooling_model.pdf  66 kB  Uploaded Tue Jul 20 12:40:07 2021  | Hide | Hide all
cooling_model.pdf
Attachment 2: IMG_9390.JPG  1.938 MB  Uploaded Tue Jul 20 15:13:32 2021  | Hide | Hide all
IMG_9390.JPG
Attachment 3: IMG_9391.JPG  2.064 MB  Uploaded Tue Jul 20 15:13:46 2021  | Hide | Hide all
IMG_9391.JPG
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