title: Dosimetry of ultrasoft x-rays (1.5 keV Al(Kalpha)) using radiochromatic films and colour scanners.
abstract: This work explores the possibility of measuring the absorbed dose of ultrasoft x-rays (USX, 1.5 keV Al(Kalpha)) with GAFCHROMIC HD-810 radiochromatic dosimetry films (HD-810 films) and colour scanners. HD-810 films were exposed to USX, soft x-rays (14.8 keV) and gamma-rays (60Co) for various times. The response of HD-810 films to absorbed doses of gamma-rays in water was calibrated with Fricke dosimetry and used for the calibration of USX. The optical density of the HD-810 films was quantified with an HP ScanJet 6100C scanner and Corel Picture Paint 7. The choice of the reading channel and colour adjustment settings were optimized to either improve sensitivity or expand the measurable dose range. The response of the HD-810 films to the absorbed dose in water decreased by 50% when the effective photon energy decreased from 1.25 MeV to 14.8 keV. The ratio of the mass energy absorption coefficient of the active layer of HD-810 films to that of water was found to play a major role in this decrease. The mean absorbed doses of the active layer of the HD-810 films exposed to USX were derived. The calculation of the initial photon fluence rate and the mean absorbed doses of USX to biological samples such as plasmid DNA is discussed. This study suggests that radiochromatic dosimetry films are promising secondary dosimeters for measuring the absorbed dose of USX.
authors.affiliation: Group of the Canadian Institutes of Health Research in the Radiation Sciences, Département de Médecine Nucléaire et Radiobiologie, Faculty of Medicine, Université de Sherbrooke, Quebec J1H 5N4, Canada. Zhongli.Cai@USherbrooke.ca
authors.forename: Zhongli
authors.initials: Z
authors.lastname: Cai
authors.forename: Xiaoning
authors.initials: X
authors.lastname: Pan
authors.forename: Darel
authors.initials: D
authors.lastname: Hunting
authors.forename: Pierre
authors.initials: P
authors.lastname: Cloutier
authors.forename: Rosalie
authors.initials: R
authors.lastname: Lemay
authors.forename: Léon
authors.initials: L
authors.lastname: Sanche
mesh_terms: D003116:Color; D016287:Computer Peripherals; D005373:Film Dosimetry / Q000295:instrumentation* / Q000379:methods*; D005720:Gamma Rays; D011829:Radiation Dosage; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012984:Software; D014965:X-Rays