Absolute efficiency of (ZnCd)S : Ag phosphor under fluoroscopy conditions

Abstract

Absolute efficiency of ZnCdS:Ag screens excited by an electron beamThe absolute x-ray efficiency of (ZnCd)S: Ag phosphor screens was measured under fluoroscopy conditions as a function of x-ray tube voltage and for different screen weights. The screens were prepared by sedimentation. Two types of grain size were used, i.e., 2-3 and 10 JA-m. The authors calculated the matching factor of some phosphor-photocathode combinations.

Evaluating x-ray detectors for radiographic applications: A comparison of ZnSCdS:Ag with and screens

“…The phosphor material used was ZnS 60 CdS 40 :Ag, which was supplied by Derby Luminescence, UK, in powder form with 10 µm grain size (code ZDB/F3). Phosphor screens were prepared by sedimentation (Nomicos et al 1978) of the phosphor powder on silica substrates with screen coating thicknesses 20,35,55,70,82,114,145 and 220 mg cm −2 . Phosphor screens of Gd 2 O 2 S:Tb (code GT1016) and Y 2 O 2 S:Tb (code YTO/70) were similarly prepared for comparison with the ZnSCdS:Ag screens.…”

“…Silver-activated zinc-cadmium sulphide (ZnSCdS:Ag) is a phosphor material of relatively short decay time that has been widely used in electron to light converting screens, as in TV tubes and in image intensifiers (Lumilux Data Book 1989). Initial results on the luminescence of ZnSCdS:Ag phosphor screens have been obtained under radioactive isotope excitation (Ludwig 1971) or under fluoroscopic conditions (Nomicos et al 1978) in transmission mode of measurement, referring to front screen-photocathode configuration of image intensifiers. Both studies reported high luminescence efficiencies for ZnSCdS:Ag phosphor, better than those of CaWO 4 :Pb, CsI:Tl, or Gd 2 O 3 :Eu (Ludwig 1971).…”

Radioluminescence : A simple model for fluorescent layers - analysis and applications

“…The largest deviation between modelled results and measurements of extrinsic (absolute) efficiency are for the series found in the scientific literature (i.e. : Wickersheim et al, 1970;Nomicos et al, 1978;Kandarakis et al, 1996). It is also notable that the Hamaker-Ludwig model-based series (Ludwig, 1971) (La2O2S:Tb), produces results close to that of the LAC-model.…”

“…The dead layer thickness is assumed to be ~0.1 µm. The work of Kuboniwa et al is widespread and is referred to in the following examples of papers on extrinsic efficiency (or the equivalent); Nomicos et al, 1978;Giakoumakis et al, 1980;Giakoumakis, 1988;Giakoumakis and Lagaris, 1988;Giakoumakis, 1989. Finally, we assume that the intrinsic efficiency, η, can be modified using the same factor to determine relative changes in the extrinsic efficiency, in the LAC-model.…”

X-ray induced luminescence and spatial resolution of phosphor screens

“…Efficiency relative to other phosphor screens (Stevels andSchrama-de Pauw 1976, Sklensky et al 1974) as well as conversion efficiency, cathodoluminescent efficiency, quantum efficiency, scintillation efficiency, detective quantum efficiency, and luminance efficiency have been studied in a large number of papers (Wang et al 1970, Alig and Bloom 1977, Swank 1973, 1974, Bunch et al 1987, Nishikawa and Yaffe 1990, Beutel et al 1993, Ginzburg and Dick 1993, Wowk et al 1994. However, the absolute efficiency of screens under fluoroscopy conditions, defined as the ratio of light flux φ emitted towards the observation side divided by the incident x-ray beam power N(n = φ/N), is of value to people dealing with x-ray intensifying screens and image intensifiers (Nomicos et al 1978, Giakoumakis and Nomicos 1985, Giakoumakis et al 1989.…”