1K Pot running warmer than usual this run, probably some ice in it but not enough to prevent cooling to base
Built the lead shield, which makes it much easier to see the 14keV and 18keV peaks
Taking drifted HV data. Nominal best noise width (PTOF) is around 34 eV, no clear improvement over Run 70 (before etching)
One mystery solved: this run and Run 70, relative calibration showed most channels very unbalanced (factors of 7 and 15). Turns out the OF time window was too restrictive for most channels. This has been corrected. (Should reprocess Run 70.)
One outstanding mystery: when we estimate Luke gain from calibrated data, the implied bias is much less than what we calculate the effective bias at the detector should be – from applied HV and corrections due to leakage current (<1%), detector charge buildup during biasing (~10%), and loss across the gap (~33%). The apparent Luke gain suggests a bias only 40% of what we calculate it should be. Nominal calculation assumes 1mm gap, it's actually smaller so bias should be even higher. It would make sense if the gap were 3 mm but no way it's that big. Calculation uses Ge dielectric constant of 16.2, it may be lower at sub-K temperature but that would predict a somewhat higher bias.
Currently scanning over biases (positive polarity, will switch to negative later).
After the bias scan data we'll try moving the source.