Ad1.)
Harris reports status of Si power supplies (PS) arrangements and change dates:
11-Sep-2020
-replace Si-N PS with one from non-magnetic PET PS system;
-set Si-N 1.5V PS to 1.63V; Si-S 1.5V PS was at 1.63V; Si HV set to 133.5V
-measure Si-N 1.5V AC 0.003V; measure Si-S 1.5V AC 0.003V
-email Andrej, Dejan, Neal Si-N PS replaced
2-Oct-2020
-measure Si-N 1.5V PS to be 1.56V, AC to be 0.003V
-change Si-N 1.5V PS to 1.44V
-measure Si-N 1.5V PS AC to be 0.003V
-measure Si=S 1.5V PS to be 1.64V; AC to be 0.003V
AS measured Si detectors, some conclusions:
- 258 is better than 257, resolution 2.9 vs 4.9 keV
- little change in lowering the voltage (ie. comparing pre Oct-2 run with post Oct-2 runs), save for higher sensitivity to noise on boundary channels, particularly 0-15 and 496-511.
Plan:
- increase voltage back to 1.63 on both PS, then swap 257 and 258 supply voltage leads.
Ad2)
Ana prepares tasks for AS to distribute at FMF. PET down, waiting for repairs.
Ad3)
Next meeting next week.
