Last modified: 14 December 2020

URL: https://cxc.cfa.harvard.edu/ciao/why/hrc_tgain.html

HRC-S Time-dependent Gain Corrections and PI Filter


A new HRC-S gain map was released in CALDB 4.9.2 (6 July 2020) and a new pulse-height filter for use with LETG data was introduced in CALDB 4.9.4 (15 December 2020). Over half of Level=2 background events can be removed at wavelenghts >20 Angstroms with a loss of ~1% of X-ray events.

The primary differences from the old gain map and PI filter are:

Relevant Plots

Users working with HRC-S data should reprocess to improve the TGAIN calibration in their data by running the chandra_repro script or by following the Create a New Level=2 Event File thread. The PI background filter is applied to HRC-S/LETG data, as explained in the "Apply background filter" section of the LETG/HRC-S Grating Spectra thread.