Új adatkönyvtár készítése hideg neutronos prompt gamma aktivációs analízishez = New data library for prompt gamma activation analysis with cold neutrons

A kutatás célja a prompt gamma aktivációs analízis korábban kifejlesztett adatkönyvtárának pontosítása volt. Ehhez felújítottuk a mintaelőkészítő laboratóriumunkat, nagy tisztaságú új vegyszereket vásároltuk (egy másik pályázat keretében) felújítottuk a mérőrendszerünket. Az új berendezésen nagyobb neutron-fluxus mellett nagyobb hatásfokkal, ugyanakkor kisebb mintatömegeket alkalmazva újramértük az egyes elemek parciális gammakeltési hatáskeresztmetszeteit és meghatároztuk a karakterisztikus vonalak energiáit. A legfontosabb (elsősorban a könnyű elemek) esetében nagy felbontású detektorral is végeztünk méréseket a korábban feloldhatatlan spektrális átfedések felbontása céljából. E mérésekkel párhuzamosan bomlási gamma-csúcsok hatáskeresztmetszetét is meghatároztuk. A spektrumokat kiértékeltük. Az új adatokat folyamatosan visszük be az adatbázisokba. Az adatkönyvtár revízióját számos módszertani fejlesztésünk is segíti. Új kalibráló standard adatokat határoztunk meg, kidolgoztuk a hibaszámítás módszereit a standardizáláshoz és az összetétel meghatározásához, továbbfejlesztettük az összetétel számító programot. Mindezek egyre pontosabb és megbízhatóbb kémiai analízist tesznek lehetővé ezzel is segítve a berendezésünknél folyó kutatómunkát. | The objectives of this project were to improve the earlier version of the spectroscopic data library used in prompt gamma activation analysis. For this purpose our sample preparation laboratory was renovated, a collection of new chemical compounds was purchased and the PGAA system was also upgraded. The increased neutron flux and the higher counting efficiency made possible measurements of higher accuracy. Smaller sample masses could be used, which made several corrections unnecessary, further improving the reliability of our results. Spectroscopic data for the important characteristic lines were determined. A high-resolution germanium detector was also used to resolve multiplets, which proved to be too complicated when acquired with the standard germanium detector of the PGAA facility. A series of short-lived nuclides were also measured, and their cross-sections were accurately determined. The spectra have been evaluated. The results are being uploaded in the spectroscopic database. Our methodological developments help the revision of the data library: new calibration data were determined to improve the method of the efficiency calculation, a new method for the determination of the uncertainties was also developed. The software used for the determination of the chemical composition was also developed. These efforts make the chemical analyses and the research, performed at our facility, more reliable

Application of the k0 method in neutron activation analysis and in prompt gamma activation analysis

ABSTRACT: The k0 method is a highly successful standard-ization method developed for Neutron Activation Analysis(NAA), later also introduced in Prompt Gamma ActivationAnalysis (PGAA). After the careful calibration of the irradi-ation and counting facilities, the k0 method makes the use ofelemental standards unnecessary. Masses of the componentsare determined relative to the flux monitor, or, in the case of PGAA, to other known components of the sample. The devel-opment of the method is summarized in this review togetherwith the description of methods implemented at differentlaboratories. The activities carried out in the laboratories ofthe authors are described as examples for the successfulimplementation of the k0 approach to activation analysis

High-energy detector calibration data for k(0)-neutron activation analysis

In k(0)-neutron activation analysis, HPGe detectors have to be calibrated up to about 3.1 MeV, in order to properly determine the Na, Ca and S content of analytes. Commercial radioactive sources cover the energy range only up to 2.2 MeV, but with activation in the reactor, additional high-energy gamma emitter radionuclides (Ga-72, Mn-56, In-116 and Na-24) can be produced. At a prompt-gamma activation analysis station, where the calibration is available up to 12 MeV, we derived accurate gamma-ray energies and relative intensities for these radionuclides and subsequently used them for broad energy-range efficiency and nonlinearity calibration of NAA detectors as well as a low-level counting station

Increasing the dynamic range for the analysis of boron in PGAA

Prompt gamma activation analysis (PGAA) is especially sensitive for elements with high neutron-capture cross sections, like boron, which can be detected down to a level of ng/g. However, if it is a major component, the high count rate from its signal will distort the spectra, making the evaluation difficult. A lead attenuator was introduced in front of the HPGe-detector to reduce low-energy gamma radiation and specifically the boron gamma rays reaching the detector, whose thickness was found to be optimal at 10mm. Detection efficiencies with and without the lead attenuator were compared, and it was shown that the dynamic range of the PGAA technique was significantly increased. The method was verified with the analyses of stoichiometric compounds: TiB2, NiB, PVC, Alborex, and Alborit

Benchmarking PGAA, in-beam NAA, reactor-NAA and handheld XRF spectrometry for the element analysis of archeological bronzes

Novel detection strategies were developed to improve the PGAA methodology in the analysis of bronze and brass objects. Instrumental neutron activation analysis and X-ray fluorescence were also involved in this study for comparison. The approach was tested on a set of IRMM-certified copper alloys. Reference values for the concentrations of four major additive components (As, Zn, Sn, and Pb) were compared with the results obtained by the involved methods. The bias observed between the reference Sn values and the initial PGAA results was successfully addressed by considering the interference of this line with low intensity copper prompt gamma peaks. In this report results are presented, and the analytical merits are compared

Searching for the double gamma-decay of the X particle

The e−e+ decay of the candidate new particle X(17) has already been confirmed by previous experiments. However, theoretical models give different predictions for the spin and the parity of this particle. The double gamma-decay process could be an appropriate probe to shed light on such properties. Thus, for the first time, we searched for the gamma-gamma decay of X(17) created in nuclear transitions. In this paper, we report preliminary results of two experiments on the Jπ= 0− -> 0+ transition in 4He

Non-Destructive Characterization of Mechanically Processed Waste Printed Circuit Boards: X-ray Fluorescence Spectroscopy and Prompt Gamma Activation Analysis

This work aimed to characterize the deportment/concentration and liberation/association of the metals and light elements within mechanically processed waste printed circuit boards (PCBs) that hold the complex and heterogeneous structure and distribution of different material components. Waste PCBs passed through a series of mechanical processing (i.e., comminution and sieving) for metal recovery and were then characterized without further destroying the particles in order to capture their heterogeneity. The characterizations were performed in a laboratory and large-scale neutron facility. The results obtained with a portable X-ray fluorescence spectroscopy and prompt gamma activation analysis were compared and confirmed the good agreement and complementarities in general. The advantages and disadvantages of the two different methods were identified and discussed in this paper, in relation to their application to the analysis of mechanically processed PCB particles