Evaluation of gamma and electron radiations impact on vitamins for onion preservation.

Food irradiation is a process in which food and other consumer products are exposed to gamma rays, X-rays or electron beams after extraction. This method is particularly important in order to reduce infectious agents and to extend the shelf life of the product. The target radiation is done with different devices, so self-sufficient radiation and panoramic radiation -including product and source overlap, planar and categorical radiation- is the major characteristics. Besides, a high performance liquid chromatography device (10% methanol, 70%-80% distilled water and 10% ethanol) is utilized to measure the chemical substance of pyridoxine (vitamin B3), thiamine (vitamin B6) and vitamin C of Vidalia or sweet onions. In our research, gamma-cell 220 and Rhodorton electron facilities were utilized to irradiate the onion crop. This project focuses on increasing the shelf life of agricultural products, especially onions, using energy of 1.25 MeV for both gamma irradiation and electron beam, and measuring the amount of vitamins B3, B6 and C, which are the nutrients of this product. The prepared onion samples were exposed under electron and gamma irradiations by two doses of 200 and 500 Gy at 25 °C. Then, a liquid chromatography device was utilized to measure the vitamins. The results showed that the onions were not damaged by 200 Gy doses and their nutritional properties were preserved, which means that not only can vitamins with this dose be retained without any spoilage for 30 days, but also eliminate pathogenic microorganisms. The process indicated that using 200 Gy radiations does not endanger the health of food and consumers.

Accelerator driven neutron source design via beryllium target and 208Pb moderator for boron neutron capture therapy in alternative treatment strategy by Monte Carlo method.

AIMS: The reactor has increased its area of application into medicine especially boron neutron capture therapy (BNCT); however, accelerator-driven neutron sources can be used for therapy purposes. The present study aimed to discuss an alternative method in BNCT functions by a small cyclotron with low current protons based on Karaj cyclotron in Iran. MATERIALS AND METHODS: An epithermal neutron spectrum generator was simulated with 30 MeV proton energy for BNCT purposes. A low current of 300 µA of the proton beam in spallation target concept via 9Be target was accomplished to model neutron spectrum using 208Pb moderator around the target. The graphite reflector and dual layer collimator were planned to prevent and collimate the neutrons produced from proton interactions. Neutron yield per proton, energy distribution, flux, and dose components in the simulated head phantom were estimated by MCNPX code. RESULTS: The neutron beam quality was investigated by diverse filters thicknesses. The maximum epithermal flux transpired using Fluental, Fe, Li, and Bi filters with thicknesses of 7.4, 3, 0.5, and 4 cm, respectively; as well as the epithermal to thermal neutron flux ratio was 161. Results demonstrated that the induced neutrons from a low energy and low current proton may be effective in tumor therapy using 208Pb moderator with average lethargy and also graphite reflector with low absorption cross section to keep the generated neutrons. CONCLUSIONS: Combination of spallation-based BNCT and proton therapy can be especially effective, if a high beam intensity cyclotron becomes available.