As a quick-look at the affect of the change in the MCP HV step I have
plotted the mean PHA and observed rate for selected events from
the diffracted X-rays from HZ43 and its zeroth order. Points are
plotted for each ObsID. The vertical dashed line separates
historical data (Nov 1999 and Mar 2011) from those of the test.
For the diffracted X-rays I selected the CRSV = 10-20 region, the area
of the lowest gain.
As expected the median PHA increases as the MCP HV step values
increase. The rate in the CRSV 10-20 range increases as the step
values are raised, indicating that we have recovered some
"QE". The evidence for an increase in the zeroth order is weaker
but we did not expect to recover any significant QE due to gain
recovery in the zeroth order.
Last modified: Thu Jan 26 14:33:38 EST 2012