Christian Segebade

High intensity photon sources for activation analysis

This review describes the basics of PAA and gives an overview of the bremsstrahlung process—conversion of high energy electrons into photons, which are essential for PAA. Various photon sources, primarily electron accelerators and bremsstrahlung converters are described, and the challenges that must be overcome before they can become practical tools are discussed. Several issues, such as neutron production, heating of the converter and the sample, and sample alignment are addressed.

Principles, methodologies, and applications of photon activation analysis: a review

This review describes the basic principles of photon activation analysis (PAA) and gives an extensive overview of its numerous applications. Uses of PAA for environmental, biological, geological, archeological, and forensic samples are reviewed. Both scientific and industrial applications of PAA are covered. Potential future uses of PAA are addressed.

Determination of gamma-ray energies and half lives of platinum radio-isotopes by photon activation using a medical electron linear accelerator: a feasibility study

In this study, we attempted to determine the gamma-ray energies and half lives of platinum radio-isotopes produced by photo-neutron reactions. Platinum was irradiated with bremsstrahlung of a clinical electron linear accelerator (c-linac). To determine characteristic gamma-ray energies and half lives of platinum radio-isotopes high resolution spectroscopy was applied. Gamma energies and half lives were measured and compared with reliable literature values for 191Pt, 195mPt and 197Pt.

Study of filling material of dental composites: an analytical approach using radio-activation

Abstract The aim of this study is to carry out elemental analyses of dental composites acquired from different producers using photoactivation analysis (PAA). High energy electrons produced by an electron linear accelerator are absorbed by a tungsten disk (Bremsstrahlung converter) thereby producing high energy X-rays (bremsstrahlung). The dental composite materials under study were exposed to the bremsstrahlung radiation whereby radionuclides were produced through photonuclear reactions. Their radioactivities were measured using high resolution semiconductor spectrometers equipped with high purity germanium detectors (HPGe). The spectra were analysed using appropriate computer software. As a result, photonuclear reactions of 12 stable elements were detected in different dental composite species, and the elemental concentrations were calculated. For comparison, the dental composites were also investigated using scanning electron microscopy (SEM) and energy-dispersive X-ray fluorescence spectrometry (EDXRF). Various sizes and shapes of dental composites were observed using SEM. However, contents of dental composites, e.g. Mg, Ni, Ba and Sr were obtained by PAA whilst C, O, Al, S, Ba and Sr were detected by EDXRF spectrometry. The results for Ba and Sr obtained using the two techniques show considerable difference.

Photon Activation Analysis at the Idaho Accelerator Center

Activation methods require minimal sample preparation and provide sufficiently high sensitivity for detecting the vast majority of the elements throughout the periodic table. In this paper we shall discuss photon activation analysis (PAA) at the Idaho Accelerator Center. The process of PAA begins with exposing a sample with photons in the energy range of 10 to 30 MeV. Many nuclides in the sample will become activated and, in turn, these radionuclides will decay by emitting characteristic radiation. These characteristic radiation decays are the telltale signatures for identifying elements which can then be measured with spectrometers such as a high‐purity Germanium detector. PAA is not an “absolute” method, as the samples under investigation must be irradiated along with a reference or calibrating material having a well‐known elemental composition. The quantitative evaluation is performed through comparing the two resulting element spectra from the unknown sample and reference material. Besides the obvious...

Photon activation analysis of sand samples from Antalya in Turkey with a clinical electron linear accelerator

Abstract The purpose of this study is to demonstrate the feasibility of elemental analysis of sand samples by photon activation induced by high energy bremsstrahlung photons at an end point energy of 18 MeV from a clinical electron linear accelerator. The γ-ray spectra of the activated samples were collected using a high resolution spectrometer. Qualitative analysis of major and trace components of the samples (12 in total) was carried out whilst the spectra of eight of the samples were evaluated quantitatively. The contents of elements obtained by photon activation analysis were compared with values obtained by X-ray fluorescence.

Determination of the Sr/Ca ratio of tooth samples by photoactivation analysis in Southern Turkey

Abstract A nuclear analytical technique, namely instrumental photon activation analysis (IPAA), was used to determine Sr and Ca concentrations in human teeth. This work was conducted using the first accelerator facility, an off-shelf clinical linear accelerator (cLINAC), in Turkey. The tooth samples supplied by the Akdeniz University Faculty of Dentistry were analyzed for determination of the Sr/Ca element ratio. The results were obtained to demonstrate the impact of socioeconomic changes on dietary habits. A calibration material (CM; a mixture of calcium and strontium oxides) was required for quantification of the analytical results. The tooth samples, together with the CM, were exposed to 18 MeV end-point energy bremsstrahlung photons from the cLINAC. Thereafter, the γ-ray spectra of the samples and the CM were obtained using high resolution γ spectroscopy. Variations in the Sr/Ca ratio in the teeth of patients fed with beef and fizzy beverages were investigated in this study.

Attenuation properties of radiation shielding materials such as granite and marble against γ-ray energies between 80 and 1350 keV

Abstract In this study, the γ-ray energy-dependent mass and linear attenuation coefficients of various granite and Turkish marble species have been experimentally obtained. Radionuclides (133Ba, 137Cs, 60Co and 22Na) with point geometry were used as γ-ray sources. The absorption capacity of each sample at nine γ-ray energies was measured using a high resolution γ-ray spectrometer equipped with a high purity germanium (HPGe) detector. To obtain the precision of the results (1σ standard deviation of the single value), this procedure was repeated six times for each species of granite and marble, respectively. The energy-dependent mass attenuation coefficient (MAC), linear attenuation coefficient (LAC), the half (HVL) and the tenth value layer (TVL) were calculated following that the MAC and LAC results were compared to the literature values.

Photoactivation Analysis of Mineral Trioxide Aggregate: Preliminary Results

Exchange Bias Effect in NdFeO3 System of Nanoparticles M. Vavraa,b,∗, M. Zentková, M. Mihalik, M. Mihalik Jr., J. Lazúrová, V. Girman, M. Perovic, V. Kusigerski, P. Roupcova and Z. Jaglicic Institute of Experimental Physics, SAS, Watsonova 47, 040 01 Košice, Slovakia P.J. Šafárik University, Faculty of Science, Košice, Slovak Republic The Vinca Institute, University of Belgrade, 11001 Belgrade, Serbia Institute of Physics of Materials, ASCR, Zizkova 22, Brno, Czech Republic MPM & FGG, Jadranska 19, 1000 Ljubljana, Slovenia