Abstract Two major advantages of polymer gel dosimeters are their ability to determine the integrated 3D dose distribution as well as their ability to the formed in different shapes. In this research, PAGAT gel dosimeter was irradiated by moderated fission neutrons in the Tehran Research Reactor (TRR) thermal column, and the response of the gel was investigated as a change in the spin-spin relaxation rate of MR image of gel Phantoms. The linearity of the response (R₂) versus the absorbed dose (D), sensitivity, dose resolution and minimum detectable dose (MDD) were investigated. For calibration of the gel response versus the dose rate, the foil activation analysis was made. In this method the flux map of the thermal column and by using flux to dose conversion factors, given by ANSI/ANS-6.1.1-1997, the flounce related to the absorbed dose map was obtained. To make sure that if there is any epithermal neutron in the thermal column a cadmium cover gold foil was set at the core nearest the thermal column. This study resulted in that PAGAT gel dosimeter can be used as a useful instrument for thermal neutron dosimetry. The sensitivity and MDD of the PAGAT gel dosimeter for thermal neutron was 0.01521±0.00552 Gy^-1s^-1 and 1.8 Gy, respectively.  

Abstract Immunoglobulin fragments offer a number of advantages for intratumor penetration over the intact antibodies. The goal of this study was to prepare F(ab')₂ fragmants from antibody PR81 and ^99mTc labeling in order to produce a biological radiopharmaceutical for imaging of breast cancer in nuclear medicine. The antibody PR81 was digested with 5% (w/w) pepsin at different times to find the best time for a complete digestion. The prepared F(ab')₂ fragments were purified by protein A column chromatography. The immunoreactivity of the complex assessed by radioimmunoassay was determined to be 65.2% ± 5.1. ^99mTc radiolabeling of F(ab')₂ fragment by using HYNIC as a chelator and tricine as a
co-ligand resulted in a radiochemical purity of 70.1%±5.2 after 1 hr with a high stability. The complex was purified by the gel chromatography method to increase the radiochemical purity. Biodistribution and imaging studies in BALB/c mice with breast tumor xenograft demonstrated as a specific localization of the compound at the site of tumors 4 h post injection with high sensitivity and minimum accumulation in non target organs. The results showed that F(ab')₂ fragment of PR81 is a promising candidate for radioimmunoscintigraphy of the human breast carcinoma.

Abstract Chemical Vapor Synthesis (CVS) route was used for synthesis of titanium dioxide (TiO₂) nanoparticles in hot-walled reactor at 800°C using TiCl₄ as precursor. The effect of processing parameters e.g., temperature and amount of precursor on phase structure, size, purity, coagulation and agglomeration of nanoparticles were investigated in this respect. Also, the H₂O effects on the size, crystallinity, phase transformation and purity of nanoparticles were studied. Comprehensive experimental observations were confirmed by transmission electron microscopy (TEM), X-ray diffraction analysis and TG-DTA results. The obtained results showed that by increasing the precursor amount and temperature, no phase transformation can be observed but the size, coagulation and agglomeration of titania nanoparticles increase. Also, the results showed that by introducing water vapor, the average particle sizes decrease saliently and no phase transformation and impurity were observed. Titanium dioxide nanoparticles can be used for synthesis of nanofluids. Nanofluids (nano-TiO_2­+­water) as a cooling agent can be used for the enhanced economy and safety of the nuclear reactors.  

Abstract Iran ranks the first producer and exporter of pomegranate in the world. Carob moth Ectomyelois ceratoniae (Lepidoptera: Pyralidae) has also been recognized as an important pest of pomegranate in the country. Due to biology of the pest, the application of pesticide has not been considered practical and the losses to this product are more than 30 percent of the yield. The application of Sterile Insect Technique (SIT) is a method that is used on a few insects with the specific characters. This research was accomplished for evaluation of the practical control of this pest upon application of nuclear methods on pomegranate. Larval and pupal stages were collected from Saveh, transferred to Agricultural, Medical & Industrial Research School and reared on artificial diet at 28±2ºC, 60±5% RH, 14:10 light: dark photoperiod. The produced pupae (young and old) were irradiated by gamma radiation and were reared with 0:0:1:1-9:9:1:1 (Irradiated male: Irradiated female: Natural male: Natural female) ratios on pomegranate fruits in the cages. The results show that the application of sterile doses (120 and 160Gy) on pupae (Young 1-2 days and old 3-4 days old) and releasing ratios 7:7:1:1 to 9:9:1:1 in comparison with the controlled treatment by the releasing ratio of 0:0:1:1 that prevents damage of E. ceratiniae on the pomegranate.

Abstract Molybdenum (Mo) content in U₃O₈ is one of the difficulties in uranium oxide production plant, as contaminant. Several methods have been proposed for reducing Mo from U₃O₈ process circuit.As a few changes in the process circuit of BUP were aimed, the loaded organic solvent containing uranium and molybdenum were stripped with acidic sodium chloride solution. The current 10% Sodium carbonate solution was substituted by 1.2M NaCl + 0.02M H₂SO₄ as a new strip solution. This method decreases Mo contents from 96.94 to 4.17 percent. With the proceeding precipitation and the calcination stages, the Mo amounts in U₃O₈ was reduced from 6.4 to 0.14 percent

Abstract One of the byproducts of uranium enrichment industry is hydrogen fluoride gas. Due to the toxicity and corrosivity of the molecule, it has adverse effects on the environment and the process. Therefore, it must be removed by adsorption towers. The activated carbon is one of the proposed sorbent for the adsorption. Hydrogen fluoride adsorption equilibrium curve gives important information for designing the adsorption towers. In this article, the hydrogen fluoride adsorption and adsorption factors were determined experimentally, and four different types of carbon have been used. The operating pressure in all tests was less than 30 mbar. Comparison between the obtained experimental equilibrium curves shows that the first, second and fourth types of activated carbon are suitable for the adsorption of hydrogen fluoride. The experimental data were fitted using mathematical models of Longmuir, Freundlich, Toth and Henry. The results show that Toth mathematical model is more suitable than other models. Also, the absolute error were predicted by the model of Toth for the first, second and fourth types of the activated carbon were 12.9, 16.5 and 34 percent, respectively.

Abstract Extraction of ytterbium from anomaly No.5 of Saghand leach solution using D₂EHPA as extractant, kerosene as a diluent, and optimization of the effective parameters were investigated. In addition to uranium and thorium, rare earths elements also exist in Saghand ore. The effect of pH on the extraction of Yb and other existing elements shows that their extractions increase by increasing pH. The extraction of Yb, U, La, Y, Ce and Fe in pH=2 were 99.9, 83, 13.5, 99.8, 8.5 and 27.4%, respectively. The increasing of the A/O ratio decreases the extraction of other elements more than Yb where it resulted in the increasing of the Yb separation. The theoretical number of extraction stages were determined in pH=2 and A/O=9 using McCabe-Thiele diagram. Stripping of the organic phase was also carried out by different concentrations of nitric acid.

Abstract On the bases of Bethe and the constant temperature models, the level density parameters have been calculated for the ³⁶Cl, ⁴⁰K, ⁶⁰Co and ⁶¹Ni nuclei, nucleuses through fitting the complete level schemes in low excitation energy levels. Both calculations reproduce experimental level densities equally well. The spins cut off parameters of the same nuclei have been determined from the analysis of experimental data for spins of low-lying states.