Scientists, Spectrometry, and Gamma-Ray Spectrum Catalogues, 1957-2007

The original Gamma-ray Spectrum Catalogue, Ge(Li) and Si(Li) Spectrometry published in 1974 by R. L. Heath has been recreated and enhanced as an electronic file and is available on CD-ROM or over the Internet. This electronic version includes 1998 -ray data from the Evaluated Nuclear Structure Data File database as downloaded in 1998 as well as decay scheme drawings. Future developments of similar catalogues will include -ray spectra from radioactive decay with newer detectors and spectra from neutron interactions with elemental samples and separated isotopes. The electronic form of these catalogues will allow the creation of tutorials on -ray spectrometry and on the data included.     

Condensation of 2-(1-ethoxyvinyl)oxiranes with sodiomalonic ester and decarboxylation of the reaction products obtained

-(1-Ethoxyvinyl)- and -(1-ethoxyvinyl)--ethoxycarbonyl--butyrolactones were obtained by the reaction of 2-(1-ethoxyvinyl)oxiranes with sodiomalonic ester. Decarboxylation of the -(1-ethoxyvinyl)--ethoxycarbonyl-butyrolactones in DMSO leads to -(1-ethoxyvinyl)--butyrolactones, the hydrolysis of which gives -acetyl-butyrolactones. Ethyl trans-3-acetyl-3-pentenoate was obtained by decarboxylation of -methyl--(1-ethoxyvinyl)--ethoxycarbonyl--butyrolactone in DMSO.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 1, pp. 22–25, January, 1992.     

A new gamma-ray spectrum catalog and library for PGAA

New measurements have been performed at the PGAA facility at the Budapest Research Reactor (BRR) in order to create a prompt -ray catalog for qualitative and quantitative analysis. The measured spectra were accurately analyzed by HYPERMET-PC. Prompt -ray energies and associated -ray production cross-sections have been determined by internal standardization. The resulting catalog contains prompt -ray data from neutron capture and other reactions such as (n,), and decay -ray data from short-lived reaction products. Data have been measured for nearly all stable elements, from hydrogen to uranium. Generally, data for several isotopes are given, to enable isotopic analysis as well. The whole library, including elemental spectra, will be available as a book.     

Effects of Cyclodextrins on Deodoration of ``Aging Odor'

Hexenal, octenal and nonenal are known causes of unpleasant body odor and are present at markedly increased levels in the middle-aged and elderly. The odor of such unsaturated aldehydes is therefore called ``aging odor'. The present study investigated the effects of cyclodextrins (CDs) on deodoration of crotonaldehyde, pentenal, hexenal, heptenal, octenal, nonenal, decenal, undecenal and dodecenal. -, - and -CD formed inclusion complexes with the majority of unsaturated aldehydes in aqueous solution. The -CD inclusion complex contained the highest amount of guest molecule. One molecule of -CD was estimated to include 1 molecule of short chain aldehyde and 2 molecules of long chain aldehyde. Deodorant testing was conducted by headspace gas analysis using sealed vials. All CDs decreased the concentrations of unsaturated aldehyde. With nonenal, the deodorant power of parent CDs was -CD > -CD > -CD, and that of chemically modified CD was Me-CD > HP-CD > G2-CD > MCT-CD. CDs were demonstrated to reduce ``aging odor'. Me-CD was the most effective type of CD for the deodoration of ``aging odor'.     

A new improved expression for gamma-ray detection efficiency of Ge(Li) detectors

In the present paper, a new improved expression for -ray detection efficiency of Ge(Li) detectors, ⁰ , is given. It is represented as a continuous function of x (viz. E ^–1) with a maximum and decreases very rapidly to a small positive value as -ray energy, E, drops to 40 keV or lower, but slowly as E rises to 1.7 MeV or higher. Since it can well represent the whole physical process of the -ray detection, this expression may be one of the simplest and most precise representations, for ⁰ at the present time.     

Recent developments in HYPERMET PC

HYPERMET PC is a user-friendly -ray spectrum analysis software package developed at Budapest, mainly for the purpose of prompt- neutron activation analysis (PGAA). The peak fitting algorithm is an improved version of the well-known HYPERMET code, and contains a partial peak-parameter calibration to describe peak shapes more accurately in the wide energy range typical for prompt- spectra. A nuclide identification routine has also been developed using a new PGAA library, shown in a parallel paper. The new module for quantitative PGAA includes all the features necessary to obtain concentration values for elements.     

A digital photopeak integration in activation analysis

A study of the precision attainable by two methods of -ray photopeak computation has been carried out. The total peak area method (TPA) and the proposed new method have been compared. The method offered is digital and simulates repeatedly accumulations of -ray spectra. The method described here computes the apparent net peak area without a clear distinction between peak and non-peak related channels. The proposed method is considered to be the most advantageous because of its relatively high precision.     

Determination of attenuation coefficient for self-absorption correction in routine gamma ray spectrometry of environmental bulk sample

A simple method to determine -ray attenuation coefficients using Ba-133 -rays has been developed and applied to self-absorption correction in routine -ray spectrometry for environmental samples composed of unknown matrix elements. Experimental values of the mass attenuation coefficient obtained by the method agree well with calculated values for samples of known elemental composition which was determined by means of chemical analysis.     

Studies in dipyridyl chemistry. VII. Sulfur trioxide sulfonation of γ,γ′-dipyridyl

Reaction of ,-dipyridyl with sulfur trioxide at room temperature gives ,-dipyridyld'isulfotrioxide, which latter on heating at 200° gives ,-dipyridyl-sulfonic acid. Salts of ,-dipyridyl-3-sulfonic acid are prepared, among them the potassium, sodium, barium, and 3-cyano-,-dipyridyl salts.For Part VI see [1].     

Uranium and thorium determination in Brazilian coals by epithermal neutron activation analysis

An experimental technique has been developed to determine impurities in coal. Uranium was determined by counting the²³⁹Np 106.1 keV -ray with a LEPS detector and thorium by counting the²³³Pa 311.8 keV -ray with a Ge(Li) detector. Seventeen coal samples were analyzed with an average precision of 3% and a quantitative determination limit of 0.153 g/g for uranium and 0.078 g/g for thorium. The technique allows determinations of up to twenty elements besides U and Th and can be applied in routine analysis.     

Nondestructive determination of lead-210 and radium-226 in sediments by direct photon analysis

A method is described for the non-destructive determination of²¹⁰Pb and²²⁶Ra in sediments. The procedure is based on the direct counting of the 46.5-keV -ray of²¹⁰Pb and the 351.9-keV -emission of²¹⁴Pb. The self-absorption of the 46.5-KeV -ray is corrected using a technique involving direct gamma transmission measurements on sample and efficiency calibration standard. Several reference materials when assayed by the described method yielded results in general agreement with the certified values. The application of the method is illustrated through the analysis of the excess²¹⁰Pb profile of a Lake Ontario sediment core.     

Synthesen von kernsubstituierten N,N-Diphenyl-β-alaninen

Zusammenfassung N,N-Diphenyl--alanine mit Substituenten in einem oder in beiden Phenylresten wurden durch Umsetzung von entsprechenden Diphenylaminderivaten mit -Propiolacton erhalten. In ähnlicher Weise reagierte Diphenylamin mit -Butyrolacton zu -(N,N-Diphenylamino)-buttersäure. 4,4-Diäthyldiphenylamin und 2-Chlor-6-methyl-diphenylamin wurden als Ausgangsmaterialien für die entsprechenden -Alanine hergestellt.

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N.N-Diphenyl--alanines with substituents in one or in both of the phenyl groups were synthesized by reactions of the corresponding diphenylamine derivatives with -propiolactone. Similarly diphenylamine reacted with -butyrolactone to give -(N.N-diphenylamino)-butyric acid. 4.4-Diethyldiphenylamine and 2-chloro-6-methyldiphenylamine were prepared as starting materials for the corresponding -alanines.

     

Effect of cascade coincidences on the efficiency calibration of a gamma-X detector

The sensitivity on n-type gamma-X detectors for low-energy X- and -rays calls for coincidence corrections in the efficiency calibration that do not apply to the calibration of p-type detectors. Corrections were calculated for the effect of cascade coincidences between -rays, X-rays, annihilation radiation, and bremsstrahlung, for 15 radionuclides frequently used for efficiency calibration. Experimental results are presented for a -X detector with 37% relative efficiency at distances from 0.9 to 17.5 cm. After coincidence correction smooth efficiency curves were found for the energy range 12 to 2750 keV, even for the position closest to the detector.     

Thermal Decomposition of Secondary N-nitramines Having 1,2,4-Triasole and Tetrazole Substituents

Thermal decomposition of secondary N-nitramines having azole substituents in the position is faster by almost two orders of magnitude than the decomposition of -substituted analogs. The rate-determining stage is homolytic dissociation of the NÄNO₂ bond. An alternative route of thermal decomposition of -tetrazolyl-substituted N-nitramines involves initial clavage of the tetrazole ring.     

1-Aryl-6-azauracile, 5. Mitt.: Die Synthese von 1-(β-Pyridyl)-6-azauracil-5-carbonsäure und einiger ihrer Derivate

Zusammenfassung Analog wie in vorherigen Mitteilungen^1–4 wurden -Pyridyl-hydrazono-cyanacetylcarbamidsäureäthylester (1), 1-(-Pyridyl)-5-cyan-6-azauracil (2), 1-(-Pyridyl)-6-azauracil-5-carbonsäure (3), deren Thioamid (4), und Amidoxim (5), welches in 1-(-Pyridyl)-5-[5-methyl-1,2,4-oxdiazolyl(3)]-6-azauracil (6) überge-führt wurde, hergestellt.

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-Pyridylhydrazono-cyanacetylcarbamic acid ethyl ester (1), l-(-pyridyl)-5-cyano-6-azauracil (2), 1-(-pyridyl)-6-azauracil-5-carboxylic acid (3), its thioamide (4) and amidoxime (5) were prepared as described in preceding communications. (5) was converted into l-(-pyridyl)-5-[5-methyl-1,2,4-oxdiazolyl(3)]-6-azauracil (6).

     

Binding and catalytic behavior of modified γ-cyclodextrins

Modified -cyclodextrins appended by an aromatic moiety show unique binding behavior, including a guest molecule together with the appended moiety in their -cyclodextrin cavities. Excimer formation, photoresponsive binding, association with -cyclodextrin and enhanced catalytic activity have been explained on this basis.     

188Os Low Excited Levels

The -ray spectra of ¹⁸⁸Re decay have been studied by using a compton-suppressed spectrometer and a three parameters --T list coincidence system. Six -rays at 557, 810, 1463, 1867, 1936 and 2022 keV and three levels at 1443, 1936 and 2022 keV are confirmed again. Eight new -rays at 309.60±0.04, 826.90±0.02, 979.29±0.08, 1086.13±0.03, 1103.7±0.4, 1828.2±0.1, 1842.5±0.2, 1982.5±0.2 keV have been identified, three new levels at 309.60, 1828.2 and 1982.5 keV are assigned. The ^–-decay branching ratio is deduced.     

High precision determination of uranium in ore by gamma-ray spectrometry

A new approach for the determination of elemental uranium in uranium bearing ore, using high resolution -ray spectrometry, was applied. Using a variant of the enrichment technique an agreement of better than 1% has been obtained between -ray measurement results and a certified value obtained by other analytical methods. For the calibration of the -ray spectrometer uranium reference samples have been used which are made available jointly in Europe and the USA as Certified Reference Materials for Gamma-Ray Spectrometry (EC NRM 171 and NBS SRM 969, respectively). The measured ore has been put in a special designed container which ensured in all directions seen from the radiation window an uniform degree of infinite thickness of about 95%. The results can be taken as an example for the applicability of -ray spectrometry when high accuracy is required and under conditions were homogeneously distributed elemental uranium is embedded in larger amount of matrix material.     

A systematic theory of one-cell differential thermal analysis

The mathematical theory is developed for heat transfer in the cells of DTA instruments with no temperature gradient. Equations are derived for the various portions of the differential curve. The concepts of real and hypothetical base lines are introduced and rules are formulated for plotting them. Three methods are proposed for processing the curves, with and without the introduction of base lines. The physical meanings of the geometrical elements of the thermal curves and their relationship with the experimentally determined thermal quantities are elucidated. Equations in differential and integral forms are derived for the base line of the cell and the base line of the reaction.

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Zusammenfassung Eine mathematische Theorie für den Wärmeübergang in Zellen von DTA-Geräten ohne Temperaturgradient wird entwickelt. Für die einzelnen Abschnitte der differentiellen Kurve werden Gleichungen abgeleitet. Das Konzept der reellen und hypothetischen Grundlinien wird eingeführt und Regeln für deren Konstruktion werden aufgestellt. Drei Methoden zur Darstellung der Kurven mit und ohne Einführung der Grundlinien werden vorgeschlagen. Die physikalische Bedeutung der geometrischen Elemente der thermischen Kurven und deren Beziehung zu den experimentell bestimmten thermischen Größen werden klargestellt. Für die Grundlinie der Zelle und für die der Reaktion werden Gleichungen in differentieller und integraler Form abgeleitet.

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A new detection method of99Tc by nuclear excitation

A new nuclear excitation process,⁹⁹Tc (, )^99mTc reaction, was applied for the first time to radioactivation analysis of technetium. Bremsstrahlung irradiation of⁹⁹Tc samples gave the reaction product^99mTc which emits -ray measurable with ease by a semiconductor detector. The production rate of^99mTc per g⁹⁹Tc was linearly correlated with the flux of bremsstrahlung. The detection limit of⁹⁹Tc was estimated to be nanogram order (0.63 Bq⁹⁹Tc) under the optimum irradiation condition. Possible interference by¹⁰⁰Ru(, p)^99mTc reaction was also studied, which could be discriminated from the (, ) reaction by simultaneously occurring⁹⁸Ru (, p)⁹⁷Ru reaction.