EDS systems are generally very stable in normal laboratory environments. Si(Li) detectors on SEMs have lasted for many years but it is too early to tell if SDD will be as durable. Detectors on TEMs are subject to a more hostile environment dominated by high-energy electrons and X-rays. Detectors on TEMs are provided with shutters which should be closed, except when a spectrum is being collected, so that the crystal is protected.

The performance of EDS detectors may be degraded by buildup of hydrocarbon contamination or ice on the detector window or by loss of the high vacuum within the detector. Low-energy X-rays are more affected than higher energy X-rays, so the performance of the detector can be monitored by recording the change in the L/K ratio, i.e., the number of X-ray counts in the Lα peak compared to that in the Kα peak for a standard reference material, e.g., Co, Ni or Cu.

EDS can be calibrated for electronic drift by fixing the zero channel and gain by reference to a spectrum of the same material. Metals such as Co, Ni or Cu are commonly used as they have a peak (the Lα peak) at low energy that can be used to fix the zero position of the spectrum, and a peak at higher energy (the Kα peak) that can be used in combination with the Lα peak to rectify gain errors. This will ensure that X-ray counts are plotted in the correct energy channels.

The EDS can be calibrated by reference to a sample that has a peak at low energy so that the zero position of the spectrum can be fixed, and a peak at higher energy so that gain errors can be corrected. The performance of the detector can be monitored by recording the ratio of the number of X-ray counts in the Lα and Kα peaks.