Title :
Characterization of polycrystalline TlBr films for radiographic detectors
Author :
Bennett, P.R. ; Shah, K.S. ; Cirignano, L.J. ; Klugerman, M.B. ; Moy, L.P. ; Olschner, F. ; Squillante, M.R.
Author_Institution :
Radiat. Monitoring Devices Inc., Watertown, MA, USA
fDate :
6/1/1999 12:00:00 AM
Abstract :
Vapor deposited films of thallium bromide are evaluated as potential photoconductive layers in new large-area radiographic detectors. The attractiveness of the material lies in its inherent high effective atomic number and high density. Polycrystalline films up to 200 μm have been grown and show a columnar structure with grains reaching 100 μm in diameter. Current-voltage (IV) tests indicate a bulk resistivity of 109-1010 Ω·cm, limited by ionic conduction. Instability of current with time is also observed, but it can be minimized with cooling. The films demonstrate high gain at relatively low field strengths as compared to other photoconductive layers. Benefits and drawbacks of TlBr are compared to other materials, and possible solutions are discussed
Keywords :
X-ray detection; diagnostic radiography; semiconductor counters; semiconductor thin films; thallium compounds; vapour deposited coatings; wide band gap semiconductors; TlBr; bulk resistivity; inherent high effective atomic number; ionic conduction; low field strengths; photoconductive layers; polycrystalline TlBr films; polycrystalline films; radiographic detectors; thallium bromide; Atomic layer deposition; Atomic measurements; Conducting materials; Conductivity; Cooling; Detectors; Photoconducting materials; Photoconductivity; Radiography; Testing;
Journal_Title :
Nuclear Science, IEEE Transactions on
