Timer error as well as its convention is very important for dose accuracy during irradiation. This paper determines the timer error of irradiators at Secondary Standard Dosimetry Laboratory (SSDL) in Nigeria. The irra...Timer error as well as its convention is very important for dose accuracy during irradiation. This paper determines the timer error of irradiators at Secondary Standard Dosimetry Laboratory (SSDL) in Nigeria. The irradiators are Cs-137 OB6 irradiator and X-ray irradiators at the Protection level SSDL;and Co-60 irradiator at the Therapy Level SSDL. PTW UNIDOS electrometer and LS01 Ionization chamber were used at the Protection Level to obtain doses for both Cs-137 OB6 and X-ray irradiators while an IBA farmer type ionization chamber and an IBA DOSE 1 electrometer were used at the Protection Level SSDL. Single/multiple exposure method and graphical method were used in the determination of the timer error for the three irradiators. The timer error obtained for Cs-137 OB6 irradiator was 0.48 ± 0.01 s, the timer error for the X-ray irradiator was 0.09 ± 0.01 s while the timer error obtained for GammaBeam X200 was 1.21 ± 0.04 s. It was observed that the timer error is not affected by source to detector distance. It was also observed that the timer error of Co-60 Gamma X200 irradiator is increasing with the age of the machine. Source to detector distance and field size do not contribute towards the timer error of the irradiators. The timer error of the Co-60 Gamma X200 irradiator (the only irradiator among the irradiators with a pneumatic system) increases with the age of the irradiator.展开更多
This paper presents results of PMMA （polymethylmethacrylate） dosimeters calibrations that are used as routine dosimeters in CDTN （Nuclear Technology Development Center） Gamma Irradiation Laboratory. The study was ...This paper presents results of PMMA （polymethylmethacrylate） dosimeters calibrations that are used as routine dosimeters in CDTN （Nuclear Technology Development Center） Gamma Irradiation Laboratory. The study was carried out within the framework of the Facility Quality Assurance Program with the purpose of to determine the calibration curve and accuracy of the Harwell Amber Perspex 3042 W dosimeters. The irradiations of the dosimeters were made in operational conditions of a Gamma lrradiator at CDTN, an R ＆ D （research and development） institute connected to the CNEN （National Nuclear Energy Commission） （Brazil）. The values for estimate of the expanded uncertainties achieved are typical of a routine dosimetry system.展开更多
文摘Timer error as well as its convention is very important for dose accuracy during irradiation. This paper determines the timer error of irradiators at Secondary Standard Dosimetry Laboratory (SSDL) in Nigeria. The irradiators are Cs-137 OB6 irradiator and X-ray irradiators at the Protection level SSDL;and Co-60 irradiator at the Therapy Level SSDL. PTW UNIDOS electrometer and LS01 Ionization chamber were used at the Protection Level to obtain doses for both Cs-137 OB6 and X-ray irradiators while an IBA farmer type ionization chamber and an IBA DOSE 1 electrometer were used at the Protection Level SSDL. Single/multiple exposure method and graphical method were used in the determination of the timer error for the three irradiators. The timer error obtained for Cs-137 OB6 irradiator was 0.48 ± 0.01 s, the timer error for the X-ray irradiator was 0.09 ± 0.01 s while the timer error obtained for GammaBeam X200 was 1.21 ± 0.04 s. It was observed that the timer error is not affected by source to detector distance. It was also observed that the timer error of Co-60 Gamma X200 irradiator is increasing with the age of the machine. Source to detector distance and field size do not contribute towards the timer error of the irradiators. The timer error of the Co-60 Gamma X200 irradiator (the only irradiator among the irradiators with a pneumatic system) increases with the age of the irradiator.
文摘This paper presents results of PMMA （polymethylmethacrylate） dosimeters calibrations that are used as routine dosimeters in CDTN （Nuclear Technology Development Center） Gamma Irradiation Laboratory. The study was carried out within the framework of the Facility Quality Assurance Program with the purpose of to determine the calibration curve and accuracy of the Harwell Amber Perspex 3042 W dosimeters. The irradiations of the dosimeters were made in operational conditions of a Gamma lrradiator at CDTN, an R ＆ D （research and development） institute connected to the CNEN （National Nuclear Energy Commission） （Brazil）. The values for estimate of the expanded uncertainties achieved are typical of a routine dosimetry system.
