A low energy (200 keV) accelerator routinely used as a neutron generator has been modified and a procedure established to extend the use to include proton induced X-ray emission (PIXE) analytical method. With these modifications, the generator has been used to measure the proton induced X-ray emission cross sections for twenty-eight elements ranging from aluminium to lead at 160 keV bombarding energy. Using these cross sections, the minimum detection limits for trace element determination in a rock matrix of average atomic number 13 have been evaluated.
A procedure has been developed to use the recoiled protons produced in neutron-proton scattering process for fast, nondestructive
determination of the hydrogen contents of coal samples. Samples from Hungary, Poland and Russia have been bombarded with 2.85
MeV neutrons from a small home-made neutron generator and the recoiled protons detected by a simple surface barrier detector.
To convert proton counts into hydrogen content, a calibration procedure was established for the method using prepared standards
of known hydrogen content and range for 2.85 MeV protons. Exploratory results obtained by this method compare favourably with
those obtained by the neutron reflection method.
For the fast and nondestructive determination of oxygen content in rock samples the 14-MeV neutron activation analysis was applied. To transfer the samples between the irradiation and measuring sites a fast pneumatic system has been developed. Using powder samples of 2.5 g and measuring times of 4 min, the reproducibility of the determination is ±2%.
Alpha-spectrometric method has been used for the determination of boron in borosilicate glasses. For irradiation thermal neutrons with a flux of about 105 n·cm–2·s–1, produced in a paraffin moderator surrounding a deuteron target of a small neutron generator, were used. Alpha-particles from the reaction10B(n, ) were detected by a Si solid state detector with a resolution of about 50 keV. The sensitivity of the method is 0.05 wt % boron in glass samples.
For the non-destructive deermination of the nitrogen content in plant samples 14-MeV neutron activation analysis was applied. Using powder samples of 0.7 g, irradiation time of 1 h and measuring time of 10 min, the accuracy of the determination is about +15%. The potassium content of the plant samples was determined by X-ray fluorescence analysis and correction was made for their contribution to the nitrogen activities.
The effective atomic number Z dependence of the ratio R of the intensity of elastically and inelastically scattered X-rays has been employed in the determination of the ash contents of some coal samples from Hungary, Poland and Russia. The results obtained by this method compared favorably with those obtained by the combustion method. This fast, simple and nondestructive method can therefore be used for on-line quality control of coal produced in a mine.
Impacts of macrosynoptic weather patterns on the development of the thermal excess in suburban areas of Debrecen are examined in this paper. Temperature datasets have been recorded at two heights by three automatic weather stations mounted in Debrecen (east Hungary) and a small settlement in its vicinity. An additional automatic weather station is used as a reference station outside Debrecen. Urban heat island (UHI) intensities have been calculated from the raw datasets. Impacts of synoptic conditions have been analyzed on the base of Péczely’s macrosynoptic types. It has been found that anticyclone types are more favorable from the aspect of UHI development, while cyclone types, especially the passage of warm fronts can effectively hinder the formation of strong heat islands in Debrecen.
14-MeV neutron activation analysis /NAA/ and radiochemical separation technique were used for the determination of Cu in Hungarian minerals. The separation of Cu from other elements is a possibility to avoid the interferences in the 511 keV -line.
Considering the importance of the X-ray production cross sections for the determination of the element concentrations in a
given material, we have measured them experimentally for Al Si, Sc, Ti, V, Fe, Co, Ni and Cu bombarded by protons with energies
ranging from 40 to 180 keV.
Authors:J. Csikai, S. Al-Jobori, Cs. Buczkó, and S. Szegedi
The concentrations of O, Na, Cl, V, Mn and Ni in crude oils of different origins were determined, using sampling (SNAA) and
on-stream (ONAA) activation analyses. Samples were irradiated with thermal and fast neutrons produced by a 0.3 mg252Cf source and a 14 MeV generator. The H-content and the C/H atomic ratio have been determined by thermal neutron reflection
method using an 18 GBq Pu−Be source.