Shetha Al-Dargazelli

A gas scintillation proportional chamber has been built to investigate its behaviour as a high-intensity low-energy X-ray detector using a gas mixture of argon and nitrogen. An X-ray source (55Fe) and an alpha -particle source (241Am) have been used to test the chamber. The scintillation pulse height has been studied for several anode voltages and...

The importance of reliable high voltage performance of ceramic samples in vacuum dictates the use of surface analysis for better understanding of flashover phenomenon. XPS analysis was used with three types of alumina samples, raw, chemically cleaned and metallised, in the course of studying the electric and optical performance of ceramic insulator...

Reliable high-voltage performance of ceramic insulators in vacuum is essential to a range of technical applications, such as vacuum tubes, high-energy particle accelerators and fusion reactors. The study of the electrical performance of ceramic insulators in vacuum is one of the vital tools in understanding the flashover phenomenon, which limits th...

An analysis has been made of gamma rays from the Large Magellanic Cloud (LMC) using data from the Compton Gamma Ray Observatory. After correcting for foreground gamma rays from cosmic ray (CR) interactions in our own Galaxy it is found that the gamma ray intensity maps show a displacement of peak position away from the peak of the atomic gas contou...

Recent work has focused on the presence of anisotropies in cosmic ray arrival directions for energies above eV. Here, we examine the results in some detail from the standpoint of identifying likely extra-galactic sources. Of the types of galaxy studied, those in collision, and which are within 10 Mpc of the Milky Way, are the strongest contenders.

EGRET data from the Compton Gamma Ray Observatory have been used to determine the flux of gamma rays from the Small Magellanic Cloud (SMC). When compared with data at other wavelengths it is found that the parents of the gamma rays, the initiating cosmic rays (CRs), are concentrated much more strongly than is the case for the Large Magellanic Cloud...

The factors affecting the sum peak of NaI(T1) detectors has been studied experimentally, namely the intrinsic photopeak efficiency, the geometry factor, the energy and the intensity of the incident photon beam. Several radioactive sources were used for the measurement of the intrinsic photopeak efficiency of the two NaI(T1) detectors used in this w...

The calculation of iodine x-ray escape peak intensity to that of photopeak for different sizes of NaI(Tl) scintillation crystals has been carried out.Different source-crystal distances were considered for the case of a point source receiving a conical shell of radiation. Axel's formula of escape probability was used after correcting the fluorescenc...

The temperature effect on the response function of two scintillation detectors, namely 51 × 51 mm (2 × 2 in.) and 76 × 76 mm (3 × 3 in.), has been studied in the 278–323 K (5–50°C) region. This effect was observed in the energy range of 0.34–1.4 MeV for different γ sources. A good linear correlation, between the peak position and the crystal temper...

The natural background gamma (NBG) radiation spectra were accumulated indoors, using a 7.6 cm7.6 cm NaI(Tl) detector, for a period of 18 months. Six prime peaks of different origins were chosen to study the seasonal effects on the intensity of NBG radiation spectrum in Baghdad. The energy range covered by this work stretched from 0.2 to 7.0 MeV. Th...

The natural background gamma (NBG) spectrum was accumulated inside the laboratory, with 102.88 cm3 Ge(Li) detector, to investigate bismuth natural radionuclides in the energy range of 500–1700 keV. The relative intensities of identified214Bi gamma lines were obtained from the spectrum. The results were in good agreement with that obtained from a so...

The natural background γ-radiation was observed by 102.88 cc lithium drifted germanium detector. Twenty-five lines due to Ac were observed in the energy spectrum extending from 50 to 1.280 keV. Comparison with other workers led to identifying two unknown peaks and observing four new lines. A quantitative measurement of the peaks is given in terms o...

A minimizing method for the contribution of external bremsstrahlung (EB) in internal bremsstrahlung (IB) spectra is described. It depends mainly on a good geometry arrangement of the detector chamber, choosing a low atomic number beta-stopper, and reducing the solid angle of EB relative to that of IB. A minimum value of the NEB/NIB ratio is achieva...

The natural background r-radiation was observed by 102.88 cc lithium drifted germanium detector. Twenty-five lines due to ²²⁸Ac were observed in the energy spectrum extending from 50 to 1, 280 keV. Comparison with other workers led to identifying two unknown peaks and observing four new lines. A quantitative measurement of the peaks is given in ter...

This paper describes the measurements of charge and light gain in argon-nitrogen mixtures using a gas scintillation proportional counter. The factors studied here which affect light emission, are anode voltage, nitrogen concentration and anode wire diameter. Results show that around a few percent nitrogen a maximum gain is obtainable. These results...

A multiwire proportional chamber of novel design has been built to study the feasibility of the chamber to measure high intensity X-rays. The well collimated X-ray beam was made to pass into the chamber parallel to the planes of electrodes and perpendicular to the direction of the anode wires. The chamber was tested using X-rays of energies 5.9 keV...

The production of internal bremsstrahlung accompanying β decay from radioactive nuclei of Sr90-Y90 has been studied. The β-active source of Sr90-Y90 is fixed to the source holder of an experimental chamber with good collimating arrangement. The internal bremsstrahlung is detected by a scintillation counter of good resolution and known efficiency, a...

DOI:https://doi.org/10.1103/PhysRevC.4.284.2

The production of internal bremsstrahlung accompanying beta decay from radioactive nuclei of Tl204, Pm147, and Ca45 has been investigated. The beta-active source is fixed to the source holder of an experimental chamber with a good collimating arrangement. The internal bremsstrahlung is detected by a scintillation counter of good resolution and know...