Nuclear and Radiation

This investigation uses Multi Channel Analyser (MCA) coupled with Gamma Ray Spectroscope (GRS) to investigate some common counting statistics used for radiation measurements of a 137Cs gamma source. Few statistical tests involving 25 and 100 trials for data acceptance were applied to study the stability of counting system. The statistical analysis evaluated count data on on four primary criteria; the Ratio Test, Chauvenet’s Criterion, the Chi-square test, and a control chart. The control chart also reflected almost accurate statistical data except for a minor error during few points of the 25 trial test. Fano factor was also evaluated for both trials to ascertain the measure of reliability and signal to noise ratio of the equipment. The results demonstrated that the counting system was fairly accurate, with a few exceptions. The Ratio Test, Chauvenet’s Criterion, and the Chi-square test each, was passed successfully. After evaluating the statistical data, Poisson distribution was created to better analyze the data.

An impact of floor levels and geological formation on the concentrations of indoor radon and its progeny studied inside 8 hospitals, and for three floor levels: ground, first and second. Locations of the selected hospitals had different geological formation and located in three main governorates: Erbil, Duhok and Sulaymaniya. Nuclear track detector type CR-39 (CR-39NTDs) used to measure track density of alpha particles that emitted from radon and its progeny. During spring season, 72 pair of exposure chambers (open-close chamber) equipped with 144 pieces of CR-39NTDs installed inside 24 rooms for three floors. After 90 day of exposure, exposed detectors etched in 6N NaOH at 70 ?C for 10 h. The highest and lowest radon concentration was in the hospitals of Shaheed Aso (Sulaymaniya city: 71.09±4.32 Bq.m^-3) and  Erbil Teaching ( Erbil city : 48.02±3.77Bq.m^-3) .This depended on the geological formation, type of building material, and the floor level. Therefore, the results showed that the average radon concentration and annual effective dose decreases gradually as the floor level increases. The highest and lowest of annual effective dose was found in ground and second floor, respectively. Thus, according to the annual exposure dose data, the workers are safety in most of the hospitals. More details about the type of building materials of the hospitals are listed in full paper.

Studies show that the number of debris in Low Earth Orbit is exponentially growing despite future debris release mitigation measures considered. Especially, an already existing population of small and medium debris is a concrete threat to operational satellites. Ground based DF-laser and space based Nd YAG-laser solutions which can remove at low expense and in a non-destructive way hazardous debris around selected space assets appear as a highly promising answer.

Void fraction measurements are made by the gamma radiation method in crude oil-water two phase flow. To measure the void fraction, the required gamma-ray source and the strength of the source is experimentally found for oil-water two phase flow using Cs137.This is achieved by the empty small plastic tubes were used for simulating the void fraction through the mixture. The obtained results show that, the void fraction value increase with the source count rate by the NaI (Tl) counter.

In connection with conversion of Ghana Research Reactor-1 (GHARR-1) from the use of Highly Enriched Uranium (HEU) fuel to the use of Low Enriched Uranium (LEU) fuel with power upgrading which started in 2006, it is imperative to know how the spent fuel is stored. After the conversion process, the current HEU core will need a Spent Nuclear Fuel (SNF) storage cask to store the HEU fuel. Studies into suitable spent fuel storage cask are ongoing to help solve this challenge. The photon source densities of fission products, actinides and activation products relevant for assessing radiological consequence as well as designing and fabricating Spent Nuclear Fuel storage cask for GHARR-1 using local shielding material has been estimated for its 90.2% HEU fuel. Results showed that the bounding radiological dose due to hypothetical accidents can be evaluated at the end of irradiation (at discharge). Results have also proven key to the selection of shielding materials for the SNF cask.

The depth resolution function (DRF) of Secondary Ion Mass Spectrometry (SIMS) analysis has been measured by analyzing delta layers of boron in silicon in different experimental condition using Cameca Ims-6f apparatus. This function has been fitted with an analytical expression initially proposed by Dowsett et al. This is described by three parameters: the rising exponential decay, the standard deviation and the decreasing exponential decay. Physical phenomena related to these fitting parameters are well detailed, in particular, falling exponential decay characterizes the residual mixing effect. The latter is considered the main mechanism responsible for the degradation of the depth resolution in the range of the primary ions energy used in this work. It is shown that when the experimental conditions change, the parameters that govern the analytical expression vary in a satisfactory way. Our depth resolutions are compared with those of the literature. It is shown that our results are in good agreement with those of other authors.

The dependency of neutron self-shielding factor on neutron field and sample size in large sample neutron activation analysis was experimentally assessed for powdered leaves samples up to 5 g in mass. The measurements of the neutron flux depression inside the samples were used in determining the neutron self-shielding factor. The experimental results agreed with the theoretical estimation that neutron self-shielding factor is dependent on neutron flux level and sample size. Neutron self-shielding was found to increase with decreasing neutron flux level and increasing sample size and vice versa.

In this work had be determine the ratio of the drift velocity to the diffusion coefficient W/D to calculate the motion of free electrons in air and helium gas. The following parameters of the electronic motion were determined as a function of the electric field strength E, apparent energy factor, K1 and Townsend energy factor, KT for Helium gas and air at 300?K and 288?K respectively in case of Maxwell and Druyvesteyn distribution law. The transport equation solved numerically to obtain the transport coefficients values and had be fed to the equations to calculate the above parameters. The gas parameters are obtained and compared with available experimental data.

The evaluation of I0 (?) and Q0 (?) for Gold, Cupper, Thorium, Uranium and Potassium in Modified Irradiation Site of Nigeria Nuclear Reactor-1 (NIRR-1) was done using Instrumental Neutron Activation Analysis (INAA) and off-line gamma ray spectrometric technique. It was found that before the Cd-lined installation i.e. modification of the large irradiation site (A-3) of NIRR-1, the deviation parameter (?) was positive with a value of 0.024±0.002 indicating high neutron thermalization. However, after the Cd-line installation, the ?-parameter was found to be negative with a value of -0.9274 ± 0.016 indicating poor thermalization and as a consequence achieved the purposed of the modification. Further correction for Q0 to Q0 (?) and I0 to I0 (?) for the nuclides; Au, Cu, Th, U, and K in the modified large outer irradiation channel A-3 were done. Before Cd-lined installation the Q0 (?) values for Au was 15.05, for Cu was 0.88, for Th was 10.05, for U was 0.86 and for K was 90.37. However, after the Cd installation the Q0 (?) values for Au increased to 139.64, for Cu increased to 4681.32, for Th increased to16661.89, for U increased to 6141.55 and for K it increased to 133177.92. Also, before Cd-lined installation (BF), I0 (?) values for Au and Cu were 1485.410, 3.870 and after Cd-lined installation they increased to 13782.47 and 18631.64 respectively.

The occupational radiation doses for medical staff at the Sheri Kashmir Institute of Medical Sciences (SKIMS) Hospital's departments of diagnostic radiology, nuclear medicine, radiotherapy, cardiology, gastroenterology, radiological physics, and bioengineering were monitored and evaluated. To ascertain the status of their average yearly effective dosage and average cumulative lifetime exposure, 250 medical radiation employees were observed. The Radiation Safety Lab of the Department of Radiological Physics and Bioengineering at SKIMS was where the analysis for this study was completed. Based on their clinical responsibilities and expertise, the observed personnel were divided into two subgroups: technical professionals and physicians. Thermo luminescent dosimeters (TLD-BARC (CaSo4:Dy)) were used to measure the whole body doses in all categories of workers, with the exception of those in the cardiology lab and gastroenterology, for whom the TLD was worn under the lead apron (0.5millimeter lead thickness). Additionally, an extremities dosimeter was given to each of the three departments—nuclear medicine, cardiology, and gastroenterology. Radiological physics, nuclear medicine, radiation, cardiology, gastroenterology, BE, and SKIMS Medical College employees' annual average effective doses were found to be 0.26, 0.60, 0.18, 0.35, 1.37, 0.17, and 0.25 mSv, respectively. The average hand/extremity dose recorded by the department of nuclear medicine utilising the unsealed radioisotopes was 1.06mSv. Cardiology and gastroenterology, two departments that use fluoroscopic guidance for a variety of procedures, were also given an extra extremity dosimeter, and the average dosages were discovered to be 0.42 and 5.57 mSv, respectively. The measured annual dosage resulted in levels that were significantly lower than the international recommended occupational dose limit.