Time-resolved measurements with a mercury resonance ionization imaging detector

Abstract

The recently developed mercury resonance ionization imaging detector (RIID) has many potential applications in the field of imaging science. We have demonstrated that useful information can be obtained from the time-resolved ionization signal detected along with the image of the object. Clearly distinguishable time-resolved signals from resonance ionization of mercury atoms and photoelectrons created within the channels of a microchannel plate by a UV signal transition of Hg at 253.7 nm were observed. Also, a new source of noise has been identified as low-mass ion desorption by 253.7 nm radiation from the inner parts of the Hg RIID. The time-resolved signal detection allowed temporal correction for the additional noises caused by nonresonant ionization processes inside the RIID, such as photoelectric effect and low-mass ion desorption. The temporal resolution of the RIID could be used for frequency shifted radiation detection and imaging.

Dual-Wavelength Time-Resolved Resonance Ionization Imaging with Cesium and Mercury Vapors

“…It can be anticipated that the capabilities of simultaneous imaging and time-resolved modes of signal detection could broaden and improve the applications of the RIIDs. Indeed, this capability can be very useful in the detection of two targets closely located in space, as reported by Shepard et al, 5 or in the detection of two distinct features in the same object. For example, with such a detector it might be possible and useful to monitor the Raman bands of two different molecules present or absent in the sample, thus providing more comprehensive information.…”