Agata Olariu

Levels of 14C in the Terrestrial Environment in the Vicinity of Two European Nuclear Power Plants

Radiocarbon is produced in all types of nuclear reactors. Most of the C-14 released into the environment is in the form of gaseous emissions. Recent data on the C-14 concentration found in terrestrial samples taken in the vicinity of nuclear power plants in Romania and Lithuania are presented. We found increased C-14 levels in the surroundings of both power plants. At the Romanian power plant Cernavoda, we found excess levels of C-14 in grass within a distance of about 1000 in, the highest C-14 specific activity being 311 Bq/kg C (approximately 28% above the contemporary C-14 background) found at a distance of 200 in from the point of release (nearest sampling location). At the Lithuanian power plant Ignalina, samples of willow, pine, and spruce showed a C-14 excess of similar magnitude, while significantly higher values were found in moss samples. The samples were analyzed at the accelerator mass spectrometry facility in Lund, Sweden. (Less)

Dating of some Romanian fossil bones by combined nuclear methods

A set of fossil bones from Romania has been analysed by accelerator mass spectrometry and by neutron activation analysis in order to estimate their age. The temporal attributing of Malu Rosu archaeological settlement has been extensively analyzed. The radiocarbon age, determined by accelerator mass spectrometry, for this site is 5510±200 BP. This is in agreement with the age of 6000±2000 BP, obtained by the dating method based on fluorine content, determined by neutron activation analysis.

Particle Induced X-Ray Emission (PIXE) Analysis of Basella Alba L Leaves

Six groups of Basella Alba L plants grown in different conditions were analysed by using particle induced X-ray emission (PIXE) method to establish a relationship between the elemental map and growth fertiliser conditions. The target samples were bombarded with a 3 MeV protons beam at the tandem accelerator of IFIN-HH Bucharest and the X-rays were detected with a HPGe detector with a 160 eV resolution at the 6.4 keV of Kα line of iron. The concentrations obtained have an estimated error of less then 6% for most of the elements analysed.

Coincidence method for the determination of minor elements in steel by proton-induced prompt gamma-ray spectrometry (PIGE)

Abstract The concentration of minor elements in a standard steel sample has been determined by irradiation with protons of 5.5 MeV. The steel sample has been analyzed with the regular PIGE method and with the selection of the (p, n) reaction channel by measuring γ-n coincidences. This approach has resulted in a significant improvement of the sensitivity of the analysis.

Microelements in fossil bones and the estimation of age

Neutron activation analysis was used to determine microelements in Romanian fossil bones and a correlation was found between some elements and 14C estimated age of the bones. Fluorine and manganese content in the bone structure increases with the time elapsed, during the fossilization. Uranium, sodium, scandium, iron and zinc have also been determined in fossil bones but a relation with the increasing antiquity of the fossil has not been observed. Measurable concentrations of some elements together with known environmental conditions provide a relative tool of dating of bones beyond 70,000 years radiocarbon limit.

Cross-sections for the electron excitation of γ-ray fluorescence

Abstract We report cross-sections for the Coulomb excitation of γ-ray transitions up to 200 keV by the transient electromagnetic fields of electrons from an incident beam. The cross-sections for the electron excitation of γ-ray fluorescence are of the order of 10 μb for an electron incident kinetic energy of 5 MeV. The electron excitation of nuclear transitions may lead to the development of pulsed sources of γ radiation of narrowly defined energy, with an efficiency of the order of 102 photons/nC for 5 MeV electrons.

Trace analysis of ancient gold objects using radiochemical neutron activation analysis

Radiochemical neutron activation analysis has been applied to investigate the microelements in gold samples with archaeological importance. Chemical separation has allowed the determination of traces of Ir, Os, Sb, Zn, Co, Fe, Ni. Instrumental neutron activation analysis has been used for the determination of Cu.

Search for γ -Emission from Isomeric Nuclei Induced by MeV Electron Beams

In this paper we study the nuclear transitions induced by incident electrons having an energy of several MeVs. We measured the cross sections for the excitation of isomeric nuclear states by 7.7 MeV electrons. The cross sections were 1.2 μb for 111mCd, 5.5 μb for 113mIn and 7.0 μb for 115mIn. The peak activation rates were 1.8×10−12 s−1 for 111mCd, 8.1×10−12 s−1 for 113mIn and 1.0×10−11 s−1 for 115mIn, for a peak power of the electron beam of 1.8×106 W cm−2. Then we describe for the first time the results of a series of experiments in which samples containing the isomeric nuclei 166mHo and 186mRe have been irradiated with MeV electron beams. An upper limit of 17 mb has been determined for the cross section of electron-induced γ-emission from 166mHo and an upper limit of 2.2 mb has been determined for the cross section of electron-induced γ-emission from 186mRe.

PIXE ANALYSIS OF Ca AND P IN THE DOWNER COW SYNDROME

The aim of this work is the microelemental analysis of blood serum samples collected from healthy and ill cows (downer cow syndrome (DCS)). Today the origin of DCS is uncertain. At the beginning of our work, we assume some connections among the diminution of some nutritive elements from food, the activity of some enzymes and the origin of DCS. The samples were collected from cows at some animal farms on the neighbourhood of Targoviste city. To obtain a microelemental monitoring of these samples, we used a nuclear analysis method PIXE (Particle Induced X-Rays Emission) and a spectrometric one ICP (Induced Coupled Plasma). For Ca and P content of the analysed samples, we used PIXE based on the internal standard method. The ICP analysis method was used for Mg content determination. The determinations of phosphatase alkaline enzyme of analysed blood serum samples were made by a spectrometric analysis using Bessey-Lowry method. In studying diseases a significant variation in Ca, P, Mg and enzyme contents was observed. Those changes correlate with age, season of alimentation and type of disease.