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Featured researches published by B. Fazekas.


Journal of Radioanalytical and Nuclear Chemistry | 1997

Introducing HYPERMET-PC for automatic analysis of complex gamma-ray spectra

B. Fazekas; G. L. Molnár; T. Belgya; L. Dabolczi; A. Simonits

In short time activation analysis prompt gamma-activation analysis and in high rate γ-ray spectroscopy in general, the shape parameters for peaks and back ground usually vary, rendering spectrum evaluation codes based on a fixed shape calibration unsuitable. An interactive version of the well-known, fully automatic γ-ray spectrum analysis code HYPERMET has been developed in C ++ for the IBM-PC. It runs under MS-DOS, in conventional memory, and can handle up to 16k-channel spectra, recorded with CANBERRAs System 100 and AccuSpec and with ORTECs ACE plug-in MCA cards. A Windows-like graphics environment is provided with mouse controlled pull-down menus, pop-up windows and rubber band expansion. All basic features of HYPERMET such as fully automatic peak search, nonlinear fitting of multiplets with automatically adjusted Gaussian peak widths exponential tails and a complex background function have been retained. All details of the fitting procedure are recorded in a data base, hence any fitted region can be retrieved and modified interactively, even after a fully automatic spectrum evaluation. The program also provides an output peak list in SAMPO90 format for further processing. The latter format is widely used in a number of sample analysis programs such as KAYZERO a software package fork0 standardization in neutron activation analysis.


Journal of Radioanalytical and Nuclear Chemistry | 1997

The new prompt gamma-activation analysis facility at Budapest

G. L. Molnár; T. Belgya; L. Dabolczi; B. Fazekas; Zs. Révay; Á. Veres; I. Bikit; Z. Kiss; J. Östör

Prompt gamma-activation analysis (PGAA) is an important complementary technique to conventional instrumental activation analysis that can be successfully used in a number of cases when INAA is not applicable. Therefore, a PGAA facility has been constructed at the recently refurbished and upgraded Budapest Research Reactor. It occupies the end position of a new curved themal guide of 30 m length and 2.5×10 cm2 cross section which provides a clean beam of low energy neutrons. The sophisticated HPGe-BGO γ-ray spectrometer system can be operated in Compton-suppression and pair-spectrometer modes simultaneously. The octal splitting of the main BGO improves efficient pair mode operation when coincidences between pairs of opposite segments and the HPGe detector are required separately. Gamma-gamma coincidence measurements will also be possible when the new multiparameter data acquisition system is completed. One of the main tasks at the new facility will be the accumulation of new spectroscopic data for detector calibration and standardisation, as well as for the construction of a more accurate prompt γ-ray library for the chemical elements. Various applications are planned, such as the determination of hydrogen in fullerenes and of toxic trace elements in environmental samples.


Journal of Radioanalytical and Nuclear Chemistry | 2003

HyperLab: A new concept in gamma-ray spectrum analysis

A. Simonits; J. Östör; S. Kálvin; B. Fazekas

HyperLab is a new Ge gamma-ray analysis code for MS Windows, developed using object-oriented design. The novel feature of the program is the extensive use of relational database technology, which allows the efficient storage and handling of any digital data encountered in gamma-ray spectroscopy. While preserving the main concept of the predecessors (HYPERMET and its derivatives) for semi-automatic analysis of multichannel pulse-height spectra, the substantially reshaped basic routines vastly improved the stability and reliability of peak fitting. New features include the fitting of peaks with high energy tail, as well as library-directed ‘Graphical Isotope Identification’. Procedures for efficiency, nonlinearity, etc. calibrations are now highly automated. By exploiting all the benefits of MS Windows technology (point-and-click simplicity in task executions, intelligent mouse pointer, etc.) HyperLab is a versatile and user-friendly tool which the discriminating spectroscopist will find of great value.


Nuclear Physics | 1989

Particle-hole and vibrational states in doubly closed subshell 96Zr from in-beam inelastic neutron and proton scattering

G. L. Molnár; T. Belgya; B. Fazekas; Á. Verbs; S. W. Yates; E.W. Kleppinger; R. A. Gatenby; R. Julin; J. Kumpulainen; A. Passoja; E. Verho

Abstract Through in-beam (n, n′ γ) and (p, p′ γ) reaction studies, we have identified 33 levels in 96 Zr and, from (n, n′) cross section and γ-ray angular distribution data, we have made spin-parity assignments for twenty of these levels. Recent DSAM nuclear level lifetimes were combined with electronic timing measurements in interpreting these states. The 1750 keV 2 + and 2439 keV 3 + states are suggested as the lowest neutron particle-hole multiplet, of ν(3 s 1 2 , 2 d 5 2 − ) type, expected from the double closed subshell picture. On the other hand, the band built on the 1582 keV 0 + shape isomer is determined to have vibrational collectivity up to the two-phonon level. Candidates for two-phonon vibrational states of quadrupole-octupole and double octupole type, associated with the ground-state structure exhibiting octupole softness, are proposed.


Nuclear Instruments & Methods in Physics Research Section A-accelerators Spectrometers Detectors and Associated Equipment | 1999

A new method for determination of gamma-ray spectrometer non-linearity

B. Fazekas; Zs. Révay; J. Östör; T. Belgya; G. L. Molnár; A. Simonits

Abstract A new method was introduced to determine the interpolation curve for system non linearity of gamma-ray spectrometers from independent multi-gamma source measurements. The mathematical description of the method and its implementation in the Hypermet-PC program are presented. The performance is illustrated in two different energy ranges, used in NAA and PGAA respectively. As a test case, the energies of 192 Ir lines have been determined and compared with the literature values.


Nuclear Physics | 1992

Level scheme and mixed-symmetry states of 134Ba from in-beam (n, n′γ) measurements

B. Fazekas; T. Belgya; G. L. Molnár; Á. Veres; R. A. Gatenby; S. W. Yates; T. Otsuka

Abstract The decay properties of the existed states of 134 Ba below 3 MeV have been studied with the (n, n′γ) reaction. From γ-ray excitation function and angular distribution measurements, several new levels, spin-parity values and multipole mixing ratios were obtained. Lifetimes were measured by the Doppler-shift attenuation method, and reduced transition probabilities were calculated for a number of levels using the proton-neutron interacting boson model. The 2029 and 2088 keV states appear to share the properties of the lowest mixed-symmetry 2 + state.


Journal of Radioanalytical and Nuclear Chemistry | 1998

Quality assurance features of “HYPERMET-PC”

B. Fazekas; J. Östör; Z. Kiss; A. Simonits; G. L. Molnár

The γ-ray spectrum analysis code HYPERMET-PC has been significantly upgraded since its introduction in the firstk0-Users Workshop (1992). Some aspects of the implemented procedures in the new version 5.0, such as the novel approach to handle tandem LFC spectra and the benefit of using ortho-normal polynomials for fitting efficiency curves will be outlined. Having realized the importance of quality assurance in applied γ-ray spectrometry, additional utilities have been incorporated for checking system parameters: nonlinearity, energy resolution, etc. The new Nuclide Identification routine makes the program suitable for qualitative analysis both of NAA and PGAA type.


Journal of Analytical Atomic Spectrometry | 1999

Investigation of impurities in thermoluminescent Al2O3 materials by prompt-gamma activation analysis

Zs. Kasztovszky; Zs. Révay; T. Belgya; B. Fazekas; J. Östör; G. L. Molnár; Gabor Molnar; J. Borossay

α-Al 2 O 3 is one of the most important materials for thermoluminescence dosimetry. The thermoluminescent features are strongly affected by impurities, which were investigated with the non-destructive method of prompt-gamma activation analysis (PGAA). Impurities in four samples of thermoluminescent alumina materials were investigated. The precision and reproducibility of the PGAA method were also tested on standard samples spiked with B, Na, S, Cl, Fe, Cu and Ag.


Nuclear Physics | 1989

Doppler-shift lifetime measurements in 96Zr with the inelastic neutron scattering reaction

T. Belgya; G. L. Molnár; B. Fazekas; Á. Verbs; R. A. Gatenby; S. W. Yates

Abstract Lifetimes of states in 96 Zr have been extracted from the Doppler shifts of γ-rays produced by inelastic scattering of accelerator-produced neutrons at incident energies of 3.8 and 4.3 MeV. From these data and the assumption that the Blaugrund theory is applicable, sixteen lifetimes and another seven lifetime limits were determined. Special features of these types of measurements are discussed. For several levels that decay directly to the ground state, spin assignments have been deduced from the γ-ray angular distributions. From measured B( E 2) and B (E1) values, support is found for suggested collective quadrupole and octupole structures in this nucleus.


Capture Gamma-Ray Spectroscopy and Related Topics-1984: 5th International Symposium | 2008

Level structure of quasi‐magic 96Zr

G. L. Molnár; B. Fazekas; T. Belgya; Á. Veres

The 96Zr nucleus is located in the A=100 region where an extremely sharp transition from spherical to deformed shape takes place. Due to the double subshell closure at Z=40 and N=56, however, this nucleus is reminiscent of magic 90Zr rather than of transitional 98Mo, its isotone. Nevertheless, the presence of many additional states with regard to the spectrum of the former and the strong excitation of the first excited O+ state in various particle transfer reactions imply more complex structure than that of a simple magic nucleus.In order to reveal this structure the 96Zr nucleus was investigated through the (n,n’,γ) reaction, induced by reactor fast neutrons. All known levels up to 3500 keV energy were observed via their γ‐decay and for most of them spin assignments could be made on the basis of angular distribution measurements. In addition, several strong γ‐rays were discovered which are believed to connect still unknown low‐lying levels. On the basis of the present results a possibility of shape coexi...

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G. L. Molnár

Hungarian Academy of Sciences

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T. Belgya

Hungarian Academy of Sciences

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S. W. Yates

University of Kentucky

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E. M. Baum

University of Kentucky

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J. Östör

Hungarian Academy of Sciences

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Á. Veres

Hungarian Academy of Sciences

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A. Simonits

Hungarian Academy of Sciences

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