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Entry  Fri Dec 3 09:31:40 2021, Radhika, DailyProgress, Cryo vacuum chamber, Transitioning MS cooldown fitting to MCMC scheme MS.stanstan_blackcoat_fit.pdf
    Reply  Sun Dec 5 17:33:50 2021, rana, DailyProgress, Cryo vacuum chamber, Transitioning MS cooldown fitting to MCMC scheme 
Message ID: 2698     Entry time: Fri Dec 3 09:31:40 2021     Reply to this: 2699
Author: Radhika 
Type: DailyProgress 
Category: Cryo vacuum chamber 
Subject: Transitioning MS cooldown fitting to MCMC scheme 

This week I have been working towards a Markov-chain Monte Carlo (MCMC) approach for fitting Megastat cooldown data and obtaining estimates on various emissivity values. I started with a simple model, only simulating the radiative cooling from the inner shield to the test mass. I supply the test mass and inner shield temperature data, and the emissivity of Aquadag (coating both the TM and inner surface of IS) as the only fit parameter. I am using Stan for the modeling, and Attachment 1 is a copy of my stan model.

The results of the simple model are in Attachment 2. The emissivity of Aquadag is estimated as a gaussian centered around 0.7. I am still determining whether this result is "real", or if the simulation is simply returning my prior. I will look into this more before adding complexity to the model.

Attachment 1: MS.stan  1 kB  | Hide | Hide all
functions {

  real coupling(real e_inner, real e_outer, real A_inner, real A_outer) {
    
    real E;
    E = e_inner*e_outer / (e_outer + (A_inner/A_outer)*(e_inner - e_inner*e_outer));
    return E;
  }
  
  real Cp_Si(real T) {
... 66 more lines ...
Attachment 2: stan_blackcoat_fit.pdf  66 kB  | Hide | Hide all
stan_blackcoat_fit.pdf
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