Demet Demir

Determination of photon attenuation coefficient, porosity and field capacity of soil by gamma-ray transmission for 60, 356 and 662 keV gamma rays.

Gamma-ray transmission methods have been used accurately for the study of the properties of soil in the agricultural purposes. In this study, photon attenuation coefficient, porosity and field capacity of soil are determined by using gamma-ray transmission method. To this end, the soil sample was collected from Erzurum and a 2 x 2 in NaI (Tl) scintillation detector measured the attenuation of strongly collimated monoenergetic gamma beam through soil sample. The radioactive sources used in the experiment were (241)Am, (133)Ba and (137)Cs. The mass attenuation coefficients of dry soil samples were calculated from the transmission measurements. The soil samples were irrigated by adding known quantities of water and the soil-water properties were examined. It was observed that gamma-ray transmission method for determination of the soil parameters has advantages such as practical, inexpensive, non-destructive and fast analysis.

Effective Atomic Number Determination of Rare Earth Oxides with Scattering Intensity Ratio

Effective atomic numbers () of scientific samples (rare earth) were determined experimentally by scattering of 59.54 keV gamma photons from 5 Ci 241Am annular radioactive source. The scattered gamma photons were collected by using a high-resolution HPGe semiconductor detector placed at to the incident beam. This experiment was carried out on several elements in the atomic range for 59.54 keV incident photons. Photopeak efficiency and air and sample absorption corrections were performed on Rayleigh to Compton scattering intensity ratio; then the ratio was plotted as a function of atomic number and a fit curve was constituted. The effective atomic numbers of rare earth oxide samples were determined by this fit curve. Also, related parameters were determined by absorption technique with the same incident photon energy. Obtained values from this fit curve were compared to theoretical values and were found to closely agree with theoretical calculations.

Determination of K-L total vacancy transfer probabilities using a weak gamma source in 2π geometrical configuration.

The K shell intensity ratios K(β)/K(α) for 9 elements in the atomic range 40 ≤ Z ≤ 50 have been determined using a weak (133)Ba gamma source at excitation energy of 80.997 keV. The K-L total vacancy transfer probabilities (η(KL)) for these elements have been determined. K x-rays emitted by samples were detected using a CdTe semiconductor detector (resolution <1.2 keV for the (57)Co gamma ray at 122 keV) with a 2π solid angle. The measured values were compared with the theoretical values calculated using Scofields tables based on the Hartree-Slater and Hartree-Fock theories and available experimental values.

Chemical effect on the K shell x-ray fluorescence parameters of some Ce compounds

Chemical effects on the Kβ/Kα x-ray intensity ratios, fluorescence yields wK and vacancy transfer probabilities ηKL for some Ce compounds were investigated. In this study, the samples were excited by 59.54 keV γ-rays from a 5Ci (241)Am annular radioactive source. K x-rays emitted by samples were counted by an HPGe detector with a resolution of 182 eV at 5.9 keV. The experimental values were compared with the theoretical and other experimental values. The aim of these measurements was to characterize the dependence of the line position and line width with the chemical environment changes.

Studying of characteristics of the HPGe detector for radioactivity measurements

The photopeak efficiency, the peak to valley ratio, the energy resolution and the minimum detectable activity of a HPGe detector were determined experimentally for 13.81–1212.95 keV photon energy by using Am241, Ba133, Cs137 and Eu152. The photopeak efficiency was studied at the geometry with the source to detector distance of 5 cm, 10 cm, 15 cm and 20 cm. Also, it was determined theoretically. It is shown that full energy peak efficiency decreases with increases in gamma ray energy. Also, the HPGe detector offers very good resolution. This makes it a suitable detector for x- and gamma ray spectroscopy and health physics research.

Efficiency Determination for NaI (Tl) Detectors in the 23 keV to 1333 keV Energy Range

Abstract The photopeak efficiency of a NaI (Tl) detector was determined experimentally for 23‐1333 keV photon energy by using polyester coated radioisotopes 22Na, 54Mn, 57Co, 60Co, 109Cd, 137Cs, and 133Ba. The energy resolution of the NaI (Tl) detector was also measured. The data were analyzed using the Genie‐2000 from Canberra. The experimental values were fitted to an analytical function of photon energy and an agreement was observed for the entire range of the studied energies. The results have shown that the NaI (Tl) detector is a particularly attractive detector for field application, as it works at room temperature and has a high probability of detecting gamma radiation.

K Shell X-Ray Fluorescence Parameters of Some Elements in the Atomic Range

The production cross sections , the fluorescence yield , K shell X-ray intensity ratio , the vacancy transfer probabilities from K to L shell , and the level widths for some elements in the atomic range were measured. The samples were excited by 80.998 keV gamma rays from a 10 mCi 133Ba radioactive source. The K X-rays emitted by samples were detected by using a CdTe detector. These parameters have been theoretically calculated, also. The experimental values were compared with the theoretical and semiempirical values. Our experimental values closely agreed with theoretical values and other experimental values.

Angular dependence of L x-ray production cross sections for Pt and Au elements in an external magnetic field

The effect of the external magnetic field has been investigated on the Ll, Lα, Lβ and Lγ production cross sections of Pt and Au elements in the angular range 90°-150° by using an energy dispersive x-ray fluorescence spectrometer. The samples were irradiated by using the gamma rays of 59.537 keV emitted from an ^{241}Am radioisotope source of 100 mCi. The external magnetic fields have been applied two opposite directions and the magnitude of the external magnetic field has been fixed at +0.75 T and -0.75 T. For B=0, Ll and Lα groups in the L x-ray lines are found to be spatially anisotropic, while those in the Lβ and Lγ peaks are isotropic. An enhancement in the differential Ll and Lα production cross sections is observed in the presence of external magnetic field. Integral cross sections for production of Ll, Lα, Lβ and Lγ x-rays were also deduced and were found to be in good agreement with the theoretical values for B=0.

Quantitative Analysis Using Scattered Radiation with WDXRF

Abstract The coherent and Compton scattered radiation of X‐ray tube target line from the sample, instead of characteristic X‐rays, has been used for the quantitative analysis in wavelength dispersive X‐ray fluorescence (WDXRF) spectrometry. The relationships between the coherent to Compton intensity ratio versus the concentration and mean atomic number were determined experimentally. Also, a comparison of the scattered radiation method and fundamental parameters method, with respect to results, was made.