Gain Notes for Revolution 518 JEM-X1: A quite normal revolution with fine gain fitting. All the data from this revolution should be useable. Unlike the previous revolutions, the gain smoothing fits very well to the data and gain correction should be within 2% of the ideal values. The Xe line analysis confirms that apart from the usual problems just after switch on, the xenon line, as far as the survey data allows us to see, lies just about where it should. The gain correction therefore seems to have worked well, within +-1-2%. JEM-X2: No scientific data or gain history for this unit. CAO 5/2/2007