title: Photon-counting radiography with the gas microstrip detector.
abstract: We have built a proof of-concept photon-counting x-ray imaging system using a Xe:CH4 gas microstrip detector (GMD) as the image receptor, and have used this system to demonstrate several advantages of photon counting over energy integration. Our experiments spanned x-ray spectra from 10 to 50 kVp and Xe:CH4 pressures from 1 to 4 atm. When photon counting is done, the energy deposited in the detector by each incident photon can be measured on adjacent anode strips and a centroid calculation can be used to provide spatial resolution significantly better than the anode strip pitch. We measured > 11 lp mm(-1) at 13 kVp with our 200 microm pitch detector, and 8.2 lp mm(-1) at 50 kVp. The energy resolution of our GMD is 5.2% at 59.6 keV, and the space-charge limited counting rate is >2 x 10(6) mm(-2) s(-1) at 3 atm for a 30 kVp beam.
authors.affiliation: Ottawa-Carleton Institute for Physics, Department of Physics, Carleton University, ON, Canada.
authors.forename: D G
authors.initials: DG
authors.lastname: Gobbi
authors.forename: M S
authors.initials: MS
authors.lastname: Dixit
authors.forename: J
authors.initials: J
authors.lastname: Dubeau
authors.forename: P C
authors.initials: PC
authors.lastname: Johns
mesh_terms: D055592:Biophysical Phenomena; D001703:Biophysics; D004582:Electronics, Medical / Q000295:instrumentation; D005069:Evaluation Studies as Topic; D005740:Gases; D006801:Humans; D008962:Models, Theoretical; D019047:Phantoms, Imaging; D017785:Photons; D011859:Radiography / Q000295:instrumentation*; D014978:Xenon
chemical_list: D005740:Gases; D014978:Xenon