Ob-Servo Sanguis irradiator dose mapping at the Philippine Nuclear Research Institute using MCNP5 annular ring voxels

• Published in: Radiation physics and chemistry (Oxford, England : 1993) Vol. 191; p. 109835
• Main Authors: Jecong, J.F.M., Hila, F.C., Pares, F.A., Dingle, C.A.M., Guillermo, N.R.D., Baule, A.G., Solomon, H.M.
• Format: Journal Article
• Language: English
• Published: Oxford Elsevier Ltd 01.02.2022; Elsevier BV
• Subjects: Absorbed dose mapping; Angular velocity; Axes of rotation; Cardboard; Chlorobenzene; Dosimeters; Dosimetry; ECB dosimeters; Ethanol; Gamma irradiator; Irradiation; Mapping; MCNP5; Monte Carlo simulation; Nuclear physics; Nuclear research; Ob-Servo Sanguis; Radiation; Radiation sources; Simulation; Spatial distribution; MCNP5; Ob-Servo Sanguis; ECB dosimeters; Absorbed dose mapping; Gamma irradiator
• ISSN: 0969-806X; 1879-0895
• DOI: 10.1016/j.radphyschem.2021.109835

Dosimetry in radiation processing is a prerequisite for regulating the delivered absorbed dose to a material. Dosimetric measurements, however, are incapable of measuring the doses over the entire irradiation area due to impracticality. Although researchers have been using Monte Carlo simulation to calculate the entire spatial distribution of doses for different irradiation systems, it has never been done with a self-shielded Ob-Servo Sanguis irradiator. In this paper, a comprehensive absorbed dose rate mapping of Ob-Servo Sanguis irradiator at the Philippine Nuclear Research Institute is presented using MCNP5 annular ring voxels that were validated with ethanol-chlorobenzene (ECB) dosimeter measurements. Acting as the rotation plane, a 27 cm × 25 cm cardboard with 15 ECB dosimeters attached at multiple locations was rotated at constant angular velocity while exposed to five stationary vertically arranged 60Co sources. The simulated results are in good agreement with the measured dose rates. The locations with optimum dose rates were in the center, 10 cm away from the axis of rotation. At the time of measurement, the maximum and minimum dose rates were 3.18 kGy/h and 1.33 kGy/h, respectively. Considering the radiation source decay, the simulation can determine the absorbed dose rate anytime and anywhere within the irradiation chamber. •Dose mapping of the entire Ob-Servo Sanguis was done using MCNP5 annular ring voxels.•Good agreement between simulation and experiment was obtained.•Dose can be determined anytime and anywhere within the irradiation chamber.•Accurate dose uniformity ratio of Ob-Servo Sanguis irradiator chamber was determined.