Gain Notes for Revolution 2490 This is one of the later revolutions in the mission where the calibration sources have become so weak that for the best energy determination and IC Gain History table is needed. To get optimal results with this revolution it is necessary to use the IC gain history. See notes in revolutions prior to revolution 1433 to find out how to do this if you don't already know. All offline gain/energy corrections (including the IC tables) are based on the two Fe calibration sources in JEM-X1, for both units. Latest OSA software (version 10 and higher) automatically cuts out the first Science windows of data from each revolution to ensure that people do not use data from the instrument-settling period. This process can be overruled, but only by experienced users. JEM-X1 rating: Very excellent (Xe line positions within 1-2% of ideal throughout) JEM-X2 rating: Also very excellent The JEM-X2 corrections are based on the JEM-X1 Fe calibration sources, since all the Cd sources are now too weak to use. CAO 27/04/2022