Detection of primary and field-enhanced scintillation in xenon with a CsI-coated GEM detector

We report the observation of radiation-induced primary and field-enhanced gas scintillation in xenon with a Gas Electron Multiplier (GEM) detector, having an internal CsI photocathode. The measurement of the time lag between prompt and delayed pulses can be exploited to reduce the parallax error in X-ray detectors having thick conversion volumes.