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Entry  Thu Aug 5 11:53:26 2021, Radhika, DailyProgress, Cryo vacuum chamber, Cooldown model fitting for MS model_fit_v_data.pdf
    Reply  Wed Aug 11 14:58:47 2021, Radhika, DailyProgress, Cryo vacuum chamber, Cooldown model fitting for MS rad_model_fit_v_data.pdfrad_cond_model_fit_v_data.pdf
       Reply  Wed Aug 11 18:00:19 2021, Koji, DailyProgress, Cryo vacuum chamber, Cooldown model fitting for MS 
          Reply  Fri Aug 13 15:14:14 2021, Radhika, DailyProgress, Cryo vacuum chamber, Cooldown model fitting for MS rad_295_model_fit_v_data.pdf
             Reply  Fri Aug 13 21:01:42 2021, Radhika, DailyProgress, Cryo vacuum chamber, Cooldown model fitting for MS 
                Reply  Thu Aug 19 14:34:10 2021, Radhika, DailyProgress, Cryo vacuum chamber, Cooldown model fitting for MS model_fit_tm_painted.pdfmodels_painted.pdf
                   Reply  Fri Aug 20 13:44:58 2021, rana, DailyProgress, Cryo vacuum chamber, Cooldown model fitting for MS 
                      Reply  Fri Aug 20 14:05:45 2021, Radhika, DailyProgress, Cryo vacuum chamber, Cooldown model fitting for MS 
Message ID: 2643     Entry time: Fri Aug 13 15:14:14 2021     In reply to: 2642     Reply to this: 2644
Author: Radhika 
Type: DailyProgress 
Category: Cryo vacuum chamber 
Subject: Cooldown model fitting for MS 

Per Koji's suggestion, I added two terms to the expression for test mass cooling power for radiative/conductive cooling from 295K (see 2641):

P_{radiative,295K} = {\color{Green} c} \sigma (295^4 - T_{testmass}^4);  P_{conductive,295K} = {\color{Green} d} (295 - T_{testmass}).

I added 0 as a lower bound for fitting a, b, c, and d. The best fit for d came out to be neglible (on the order of 10-17): conductive heating from room temperature can be ignored. The best-fit parameters for [a, b, c] came out to:  [0.025, 0.003, 0.001]. The result can be seen in Attachment 1. 

This fit would imply that there is some radiative heating of the test mass from room temperature, in addition to expected radiative/conductive cooling from the inner shield / coldplate. It is worth investigating what might be causing this, and if nothing can be determined then the model needs to be revisited. 

Quote:

How about incorporating radiative and conductive terms from the object at 300K?

 

 

Attachment 1: rad_295_model_fit_v_data.pdf  42 kB  Uploaded Fri Aug 13 16:30:03 2021  | Hide | Hide all
rad_295_model_fit_v_data.pdf
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