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 Fri Aug 30 17:31:56 2019, anchal, DailyProgress, TempCtrl, Vacuum Can Temperature Control Setpoint Step Test Wed Sep 4 11:04:08 2019, anchal, DailyProgress, TempCtrl, Vacuum Can Temperature Control Setpoint Step Test - Results Wed Sep 4 11:49:02 2019, rana, DailyProgress, TempCtrl, Vacuum Can Temperature Control Setpoint Step Test - Results Thu Sep 5 11:15:06 2019, anchal, DailyProgress, TempCtrl, Vacuum Can Temperature Control Setpoint Step Test - Results
Message ID: 2415     Entry time: Thu Sep 5 11:15:06 2019     In reply to: 2411
 Author: anchal Type: DailyProgress Category: TempCtrl Subject: Vacuum Can Temperature Control Setpoint Step Test - Results

I used the calibration of North and South NPRO control voltage to frequency change from CTN:1948.

Then using the following formula:

$\frac{\Delta T}{\Delta V} = \frac{S[\frac{Hz}{V}]}{-\alpha [\frac{1}{K}]\frac{c[\frac{m}{s}]}{\lambda [m]}}$

where S is the calibration slope for NPRO from volts to the frequency

$\alpha$ is the coefficient of thermal expansion of fused silica, $5.5\times10^{-7} K^{-1}$

c is the speed of light 299792458 m/s

The offset was adjusted so that at t=0, the cavity temperatures is the same as the vacuum can in-loop temperature sensor reading at t=0.

This gave for the South Cavity -22.456 K/V and for the North Cavity -23.489 K/V

The South Cavity temperature changed 0.511 K, 0.539 K, and 0.565 K in the first step on the three days. Mean response to the first step is 0.538 K.

The North Cavity temperature changed 0.520 K, 0.574 K, and 0.639 K in the first step on the three days. Mean response to the first step is 0.578 K.

The South Cavity temperature changed -0.878 K, -0.860 K, and -0.863 K in the second step on the three days. Mean response to the second step is -0.867 K.

The North Cavity temperature changed -0.903 K, -0.933 K, and -0.910 K in the second step on the three days. Mean response to the second step is -0.915 K.

Code and Data

Edit Fri Sep 6 12:01:49 2019 anchal in RED above.

Found out that there is a bored hole in the spacer so the laser doesn't travel in fused silica actually. So the refractive index used above is wrong.

Updated calculations and plots for the same.

 Attachment 1: VacCanStepResponseTempAxis.pdf  372 kB  Uploaded Fri Sep 6 13:14:14 2019
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