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 Sat Aug 27 17:42:40 2016, awade, Summary, TempCtrl, Heat load of vacuum can held above room temperature. Mon Aug 29 19:09:19 2016, awade, Summary, TempCtrl, Heat load of vacuum can held above room temperature. Wed Aug 31 12:41:30 2016, awade, Summary, TempCtrl, Heat load of vacuum can held above room temperature. Thu Sep 29 17:57:32 2016, awade, Summary, TempCtrl, Heat load of vacuum can held above room temperature.
Message ID: 1712     Entry time: Wed Aug 31 12:41:30 2016     In reply to: 1709     Reply to this: 1728
 Author: awade Type: Summary Category: TempCtrl Subject: Heat load of vacuum can held above room temperature.

The full cool down curve of the tank and a fitted curve ($T = A\exp(-t/\tau)+C$)are attached below.

Least squares fitted values are

a=23.4145±-0.0005 C, tau=7596±170 s, c=21.00947±0.00004

The variance on the time constant is very large, I think this might be due to a poor fit owing to the fact that the temperature was still rising (rather than steady) when I turned the heating off. We want the whole system to be at equalibrium at the start of the test and we also want a decent tail on the decay. I have therefore repeated the measurment this time heating overnight with 30 V (18 W) which settled on 44.36 C.  I have now left the vac can to cool for the rest of the day (starting about 9.30 am).

## Either way it looks like the characteitic 1/e decay time is on the order of 2.1 hours.

 Attachment 2: plot20160829_RawDateRvsTime.pdf  54 kB
 Attachment 3: 20160829plot_TankHeatUpAndStepDown45toRoom-BokehTest.ipynb  9 kB
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