The amount of cosmic rays varies widely with the altitude, latitude and longitude in each region. In this study, the radiation doses due to the cosmic rays were estimated in two steps: in the first step, the neutron and gamma components of the radiation dose were measured for a roundtrip flight on 3 flight routes (Shiraz-Asaluye, Asaluye-Rasht and Shiraz-Mashhad) using a gamma-tracer photon detector and a Thyac 190N, neutron detector. The minimum values of the measured gamma and neutron doses of 0.15 and 0.04 mSv were measured on the Asaluyeh-Shiraz route at the lowest altitude of 19000 ft, while for Rasht-Asaluyeh route at an altitude of 35000ft those values were found to be 2.52 and 1.09mSv, respectively. In the second step, a number of aircrew members were equipped with thermoluminescence DOSIMETERS (TLD cards) for evaluating the gamma dose and POLYCARBONATE DOSIMETERS (SSNTD) for assessing the neutron dose for one year. The measured value of the annual effective dose received by the crew ranged between 0.5 mSv/y and 1.16 mSv/y, with an average of 0.9 mSv/y for the gamma component and between 0.37 mSv/y and 0.77 mSv/y with an average of 0.61 mSv/y for the neutron component. The results of this investigation are comparable with the investigations that have been conducted in other countries. For instance in UK, the reported annual effective dose of aircrew is about 2mSv, and in Canada, it is estimated to be between 1 to 5mSv, depending on the flight situations (such as the latitude and longitude of the cities, the flight altitude, etc).

Background: The compositions of Ferrous sulphate, Agarose and Xylenol orange dye (FAX) and Ferrous sulphate, Gelatin and Xylenol orange dye (FGX) in solution of distilled water and sulphuric acid are two tissue-equivalent gel DOSIMETERS. Ionizing radiation causes oxidation of Fe2++ ion to Fe3+ ions which diffuse through the gel matrix and blur the image of absorbed dose over a period of hours after irradiation. Materials and methods: 25 mM sulphuric acid, 0.4 mM ferrous ammonium sulphate, 0.2 mM xylenol orange dye and 1% by weight agarose in distilled water named FAX and 0.1 mM ferrous ammonium sulphate, 0.1 mM xylenol orange dye, 50 mM sulphuric acid and 5% by weight gelatin in distilled water named FGX are used as two gel DOSIMETERS. All chemicals were supplied by Sigma Aldridge Company, Germany . The gels were poured in Perspex casts and were irradiated to a beam of X ray from linear accelerators or x ray machine. Results: In this study diffusion coefficients of FAX and FGX DOSIMETERS have been measured through a computer program for different temperatures. The ferric ion diffusion coefficient (D) for the FAX and FGX DOSIMETERS were measured as (1.19 ± 0.03) x 10-2 cm2.hr-1 and (0.83 ± 0.03) x 10-2 cm2.hr-1 respectively at room temperature. Conclusion: For both DOSIMETERS the diffusion coefficients decreased with gel storage temperatures down to 6oC. FGX DOSIMETERS have advantage of lower diffusion coefficient for a specified temperature

Modern radiotherapy techniques try to deliver the radiation dose by steep gradient. Protocols for these complex treatment delivery techniques are important and extremely sensitive to errors in treatment delivery. To minimize such errors, 3D DOSIMETERS were developed as a relative method for improving dose monitoring and delivery. The aim of this study is to analyze the capability and drawbacks of different types of 3D DOSIMETERS such as Fricke gel DOSIMETERS, Hypoxic gel polymers, Normoxic gel polymers and 3D radiochromic solid polymer known as PRESAGE. The results of studies show that the optimum method of dosimetry in radiation therapy is using PRESAGE dosimeter.

Lexan POLYCARBONATE films were irradiated by UV radiation at wavelength l= 250 nm under different time exposures of 1, 2, 4, 6 and 7 h. Structural, optical and mechanical modifications were studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), UV–Visible spectroscopy, impedance analysis, tensile testing and rheometry methods. The crystallite size and percentage of crystallinity were found to decrease upon irradiation as was studied by XRD. It indicated that polymer was moving towards more disordered state after irradiation corroborating DSC results. FTIR Study showed the carbonate linkage is the radiation-sensitive linkage and benzene ring does not undergo any change after irradiation. SEM results showed the formation of pores after irradiation. The atomic force microscopy measurements revealed that the average roughness of the film increased after being irradiated. The glass transition temperature was observed to decrease after irradiation as revealed by DSC measurement. UV–Visible spectra showed decrease in optical band gap after irradiation due to chain scission in the Lexan POLYCARBONATE. Plot of AC conductivity versus log (f) displayed a sharp increase in conductivity at higher frequencies and dielectric constant/loss was observed to change with the irradiation time. The mechanical properties and average molecular weight of Lexan POLYCARBONATE decreased after irradiation, while the average number of chain scissions per original polymer molecule increased with increase in time of exposure.

In this work the chemical ethanol-chlorobenzene (ECB) DOSIMETERS were prepared. A cobalt-60 irradiation source was used at the dose range of 0-30 kGy. Titration, spectrophotometry, and oscillometry read-out methods were applied, and the latter method was adopted throughout this experiment. The dose responses were found to agree favourably with the ASTM standards. The homogeneity and the reproducibility of the produced ECB DOSIMETERS were also controlled and found satisfactory.

Considering the importance of quality control of radiotherapy systems and 3D dose mapping possibility done with a Fricke agarose gel dosimeter, this dosimeter based on ferrous solution and agarose gel was prepared. The prepared Fricke gel DOSIMETERS was investigated under gamma irradiation with a dose range up to 20 Gy. Concerning the effect of the gel dosimeter constituent’, s concentration on the response of the dosimeter, different compositions were surveyed for better sensitivity and repeatability. So, the responses were evaluated for different concentrations of ferrous ion, sulphuric acid, and the indicator. We found that the Fricke agarose gel dosimeter has a linear behavior up to 20 Gy. In addition, the best composition of Fricke agarose gel dosimeter with high sensitivity and stability was determined to be 0. 2 mM ferrous, 25 mM sulphuric acid, and 0. 15 mM Xylenol orange.

Purpose: To compare the complications of pegging between the POLYCARBONATE peg system and the titanium peg system.Method: Complications associated with pegging (POLYCARBONATE: Bio-Eye or titanium: Dr-Perry new P-K) were reviewed from the hospital records of 153 patients over 5 years.Results: Out of 153 cases, 96 (62.3%) were male and 57 (37.7%) were female. Mean age was 27.7 yr (6-59 yr). In 88 cases, the peg was poly carbonate with sleeve system and in 65 cases, a titannium peg was used. There was at least one complication in 41 (46.6%) cases with POLYCARBONATE and 18 (27.7%) cases with titanium (P= 0.018). The rates of the most common complications including granulation tissue, discharge, conjunctival over growth, and peg falling out were 35%, 23%, 13%, and 8%, respectively in the POLYCARBONATE peg group and 15%, 5%, 1.5%, and 0 in the titanium peg group. The rate of the last 3 complications in the titanium peg group was statistically lower than the POLYCARBONATE group. Twenty-five (28.4%) cases with POLYCARBONATE peg and 5 (7.5%) cases with titanium peg had two or more complications (P= 0.03). Peg removal for treatment of complications was required in 11 out of 41 complicated cases (28.8%) of the POLYCARBONATE group but in 2 out of 18 complicated cases (11.1%) of the titanium group (P= 0.03).Conclusion: Both pegging systems incurred complications which were less severe and less prevalent with the titanium peg system. Surgical intervention for treatment of complications in the titanium peg system was required less than the poly carbonate peg. It may be concluded that the titanium peg is a good substitute to the POLYCARBONATE peg system.

In this work,copper/palladium (Cu/Pd) multilayer nanowires were successfully prepared by electrode position method using POLYCARBONATE template. The fabrication of Pd/Cu multilayer nanowires was controlled by analyzing the current–time transient during electrode position using potentiostat. The morphological properties of the nanowires were studied by scanning electron microscopy (SEM) and result showed that almost each nanowire had the same length of » 4 mm and the diameter of 90 nm .X-ray diffraction pattern showed that Pd and Cu grow in their face-centered-cubic (fcc) lattice structures. The chemical composition was determined by examination of the energy dispersive X-ray (EDX) spectra.