Published online by Cambridge University Press: 01 March 2012
Microcalorimeter X-ray detectors using a transition edge sensor depend for their linearity and energy scale on the stability of the operating point on the transition curve. We report on some sources of energy scale drift in microcalorimeter X-ray detectors and the manner in which they have been addressed. Previously observed drifts of >10 eV∕h have been reduced to 1–2 eV∕h. This improved stability has resulted in the observation of X-ray fluorescence linewidths of ⩽12 eV over 6 h of counting time.