The spectrometric system for ionizing radiation measurement with pile-up rejection and counting losses correction has been described. The results for HpGe, Ge(Li), Si(Li) and surface barrier detectors have been presented. The total count rate ranged from 500 to 105 cps and different radioisotopes have been used. The counting losses correction accuracy has been within ±1% with tenfold reduction of background from pile-up pulses. The possibility of the system application for radiation intensity measurement of the mixture of short- and longlived radioisotopes has been discussed.
A method of uranium determination in organic and aqueous solutions has been developed, based on fluorescence L X-ray excitation
with a109Cd source of several mCi activity and counting the excited Lα lines with a proportional counter. To eliminate uranium X-ray absorption by the accompanying elements the intensity of the
source radiation (Ag K) transmitted through the analysed solution is measured. The ratio of these two intensities is independent
of other elements present in the solution over a very broad range of concentration. The analysis time does not exceed 5 minutes.
The precision and accuracy of this method in the range 0.5 to 100 g U/1 are comparable to those of the classical titrimetric
A relatively simple method of sulphur determination in drill cores of calcium carbonate matrix is described. The method is
based on the combination of measurements of backscattered beta-particles and transmitted low energy gamma-radiation intensities.
The transmitted gamma-radiation measurement corrects the errors of sulphur determination caused by the varying strontium sulphate
and silicon dioxide content. The method has been tested on 170 samples. It was estimated that the standard deviation of sulphur
determination does not exceed 2.5% of sulphur. The apparatus for routine absorption measurement is also described.
The plutonium determination by alpha-particle spectrometry with semiconductor detectors in the presence of uranium has been
described. It has been found that plutonium as well as uranium can be electrodeposited quantitatively on nickel or stainless
steel discs from solutions in isopropanol. The time of deposition does not exceed 35–40 min. The determination of plutonium
is possible within the uranium to plutonium weight ratio of 4000 with the accuracy better than 2%.
The energy dispersive X-ray fluorescence method of Pb and Ag determination in metallic copper is described. Radioisotopic
sources of57Co and241Am/target have been used for excitation and Si(Li) and hyperpure Ge spectrometers for spectra analysis. The standard deviation
of Pb and Ag determination for a single measurement is 0.015 and 0.012%, respectively.
The possibility of application of the radioactive source excited X-ray fluorescence analysis for titanium and iron determination
in kaolins to the routine test of the refinement process has been studied. The iron content can be determined with a simple
counting system using a single-channel pulse height analyser, argon filled proportional counter and109Cd source of 3 mCi for the excitation of K Fe rays. The samples were analysed both as pellets and powders. The iron content
ranged from 0.2–2.5% and titanium from 0.1–0.64%. For simultaneous determination of titanium and iron a Si(Li) spectrometer
has been used. The238Pu source has been used for K Fe and K Ti excitation. It is the most convenient source for simultaneous determination of titanium
and iron.55Fe is the most efficient source for the determination of titanium alone. The best values of precision and determination limit
have been achieved for iron with238Pu and for titanium with55Fe.
A method was developed for isolating neptunium from Pu, U or mixed oxide (MOX) samples and its determination by isotope dilution -spectrometry (IDGS) using239Np (243Am) as a spike. Extraction chromatography with trilaurylamine fixed on a SGX-C18 support was used for the isolation of Np. The decontamination factors for U, Pu, Am and Pa vary between 1000–2000 and 100, respectively. The average separation yield of Np is (95±3)%. The amount of243Am required for spiking is about 0.2–0.3 g. It is recommended to use the pair of -rays 86.53 keV (237Np)-106.13 keV (239Np) for the assay of neptunium. A relative uncertainty of 4% or better is achievable in the analysis of plutonium samples, containing 0.4–80 g neptunium. The detection limit, under the proposed experimental conditions, is about 0.05 g Np. The results were compared with the results obtained by using high resolution -spectrometry (HRGS).
The purpose of this study was twofold: the identification of some uranium compounds and a measurement of mixed U/Pu particles with different ratios of these elements. We used a Philips XL-30 scanning electron microscope equipped with an EDAX energy dispersive spectrometer with a Si(Li) detector and a super ultra-thin polymer window and with a Microspec wavelength dispersive spectrometer. A number of WDXRF and EDXRF spectra of U and Pu containing particles were accumulated and evaluated. The software package provided by the manufacturer was used for EDXRF spectra evaluation and calculation of the weight and atomic composition. Eight different U compounds were identified with a different degree of confidence. Several different types of U and Pu particles were measured using the WDXRF spectrometer and the results of the measurements are discussed. The measurement of mixed U-Pu particles showing large differences in the concentration of both elements can best be carried out with the use of WDXRF because the deconvolution of the M lines of U and Pu in the energy dispersive spectra is only possible over a relatively small concentration range. The results of particle analysis are very useful for verifying the absence of undeclared nuclear activities.
Authors:J. Kierzek, B. Maŀożewska-Bućko, L. Wawrzonek, and J. Parus
An analytical procedure for determination of Fe, Ti, V, Ni, Co and Cu, the most important constituents of the polymetallic ore has been developed. Twenty four powdered samples were prepared from the material taken in various places of the ore deposit. The samples were analyzed by wavelength dispersive (WD) and energy dispersive (ED) XRF method. The EDXRF method was applied using radioisotope source as well as a low power X-ray tube (Rh-anode) for excitation of the characteristic K-line radiation of the elements. A Si(Li) detector was used for the detection of radiation. The detection limits and precision of the analytical procedures, using reference materials, were estimated. The accuracy of the different XRF techniques is discussed. The developed analytical procedures based on the XRF method are rapid and quite simple. They can be useful for exploration data accumulation.
Authors:T. Żółtowski, J. Kierzek, J. Parus, and R. Brzoza-Brzezina
The computational method for the rapid evaluation of gamma and X-ray spectra observed by semiconductor detectors in radiometric
analysis in presented using a simple peak shape function. The computer programme includes a minimizing routine based on the
modified Newton-Raphson method giving a minimized vector of the parameters more rapidly than the conventional approach. The
spectra of some gamma-ray emitting fission products and X-ray spectra excited by radioisotopes of materials from copper ore
processing were studied. It was found that the simple Gaussian peak function gives the results equivalent to the total peak