I have added the previous calibration curve I did on 20170310. It is in a file called, "CalibrationCurve_20170310.png". This has an excel least squares fit and the equation is shown. The fit is fairly low residual. This was done with the tube before its primary ceramic to metal seal was re-done. Originally the tube was 8" long with a Swagelok seal pretty much directly to the OD of the tube. The calibration run was done with tube open, and with no contents. When the tube was modified for the new brass seal, the length was reduced by 1/2" but the brass seal stuck out beyond the tube end by about 0.8", so about 0.3" longer than the original design. I will have to run another calibration after this active run and will do it with an identical tube to what is now in the heater. Still the calibration should be pretty close.
Right now the reactor is approaching 500C and in calibration, this would have taken 61 watts according to the fit. It looks like the power of the active cell may be about 60 watts when it settles.