The first calibration process is done in He at 3.5 Bar. We are showing temperatures just a couple degrees warmer than before. Part of the difference might be that we didn't wrap the Celani wire as tight to the supports, which means that we used up the meter one wrap before the end. This may have concentrated the same amount of power into a slightly closer space.
To compensate for this, we may take the previous calibration run at 3.5 Bar in He, subtract that off, and use the difference to make an adjustment to the calibration at the loading (H @ 3.5 Bar at room temp) and running conditions (75%H/25%Ar @ 3.5 Bar at room temp) we plan. Any opinions?
The impedance of this wire performed way different, too.
More baseline data from the many calibrations. To get a sense of the effect of different gasses and pressures, we took measurements at a constant power of 110 W and plotted the temperature achieved at various pressures for each gas. I would love to plot the temperature rise vs. thermal conductivity of the gas, but haven't gotten that far, yet. Anybody wanna try that? The master database for this version is here: Master_Spreadsheet11-9.xls
We have started the second and final Helium run at 0.5 Bar. Stay tuned.