Application of a new source model of a panoramic gamma irradiator on dose map formation in an irradiated product

A Monte Carlo study to investigate the feasibility to use the Moroccan panoramic irradiator in sterile insect technique programs

Mediterranean fly pest (Ceratitis) is one of the most destructive pests of fruit species in Morocco. The sterile insect technique (SIT) is an environmentally friendly strategy that uses ionizing radiation to sterilize adult insects. Morocco has a panoramic gamma irradiator used to irradiate agri-food products. This irradiator is not dedicated to SIT programs due to its geometry that does not allow to obtain a dose uniformity ratio (DUR) recommended for such applications. This article presents a Monte Carlo study to investigate the feasibility of using the panoramic gamma irradiator at the National Institute for Agronomic Research (NIAR) of Tangier, Morocco, to setting up SIT methods and contributing to Ceratitis control programs. The Monte Carlo method was used to simulate the concrete bunker in which the panoramic gamma irradiator is installed. To obtain a recommended DUR required for SIT programs, two cells similar of the Gammacell-220 irradiator, which is mainly used in the SIT programs around the world, were simulated inside the concrete bunker. The simulation and calculations were performed using the MCNPX-2.7e Monte Carlo simulation code. It is demonstrated that at both investigated positions, the spatial distribution of dose rates in the two modeled irradiation cells, which were similar to a gammacell-220 irradiator cell, are uniform enough that the cells can be used for SIT programs. It is concluded that the panoramic irradiator at NIAR can be used to contribute to the control of Mediterranean fly pest and other insect pests in Morocco.

Dose mapping of the panoramic 60Co gamma irradiation facility at the Ruđer Bošković Institute - Geant4 simulation and measurements

The paper presents the dose mapping of the panoramic ⁶⁰Co gamma irradiation facility at the Ruđer Bošković Institute in Croatia. Both experimental (using ionisation chamber) and simulation (using the Geant4 Monte Carlo code) studies have been performed and compared. Measured and simulation dose rates are found to be in very good agreement and can be used for the absorbed dose determination in the irradiation chamber in everyday work. In order to get a complete description of the dose distribution in the facility, the transit dose, which has to be taken into consideration at low doses, was also experimentally determined.