11251

10342

كارشناسي ارشد

هسته اي

اصفهان: دانشگاه صنعتي اصفهان، دانشكده فيزيك

1394

شانزده،130ص.: مصور

احمد شيراني، جمشيد خورسندي

مهدي رضواني

محمدحسن علامت ساز، ظفرالله كلانتري

1395/02/19

فيزيك

ID10342

Abstract The iodine element in people s food is very important and according to the availableinformation the central part of Iran is located in the belt of iodine deficiency So it isnecessary to determine the exact amount of this element In this research concentration ofthe element iodine in various kinds of salts including sea salts and processed iodised saltshave been measured These measurements have been done by neutron activation analysis using epithermalneutrons ENAA along with construction of cadmium capsule in Isfahan MiniatureNeutron Source Reactor MNSR The results of these experiments have been comparedwith the results of the ordinary methods of thermal neutron activation analysis andcapsules containing the element boron and the accuracy of this method has beenconfirmed According to this study due to low concentration of iodine in salt and its lowabsorption cross section for thermal neutrons and also due to presence of highconcentration of interfering nuclide Na which unlike iodine has a high absorption cross section for thermal neutrons the use of epithermal neutrons has increased the sensitivityof this method By using cadmium capsules which were made for this purpose without theuser receives a significant dose and with radiation protection provisions and the results ofMCNP code the samples can be analyzed and iodine in samples can be measured withhigh accuracy The flux of epithermal neutrons obtained from MCNP code in the cadmiumcapsule is more than the flux of epithermal neutrons in boron capsules Since the element iodine is highly sensitive to temperature capsule containing boroncompound are not suitable because they emit particles which increase the temperature ofthe capsule which leads to iodine evaporation and therefore reduces the accuracy of themethod If sealing and packaging of capsules are not done carefully it causes the capsulebecome open inside the reactor therefore reactors safety is extremely problematic and isnot recommended Now according to the results of this study cadmium capsules are usedin similar cases in the miniature neutron source reactor Key words salt iodine epithermal neutron activation analysis epithermal neutrons cadmium capsules boron Capsule radiation protection Miniature Neutron SourceReactor MCNP measurement precision

احمد شيراني، جمشيد خورسندي

مهدي رضواني

محمدحسن علامت ساز، ظفرالله كلانتري