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Comparative Study of the Methods Used for the Computer Resolution of Composite Gamma-Ray Spectra; Etude Comparative des Methodes Utilisees pour la Resolution de Spectres Gamma Complexes au Moyen d'un Ordinateur; Sravnitel'noe izuchenie metodov razresheniya sostavnykh gamma-spektrov pri pomoshchi schetno-reshayushchego ustrojstva; Estudio Comparativo de los Metodos Aplicados para Resolver Espectros Gamma Complejos Mediante Calculadoras

Conference:

Abstract

The resolution of complex mixtures of gamma-ray emitters has been expedited by the use of highly sophisticated gamma-ray spectrometers in association with digital computers. These instruments have now become generally available or easily accessible to technical laboratories. This paper discusses the techniques used in this laboratory to obtain the concentrations of individual gamma-emitting radionuclides in fallout samples and compares the results obtained by the various mathematical methods on composite samples. The computer derived data are compared with results obtained by radiochemical analysis of the sample. Binary mixtures were analysed by methods outlined below and then the analysis was extended to the many component system. A computer method was developed which normalizes gamma-ray spectra to minimize the effect of long-term spectrometer drift and converts the spectrum to an energy co-ordinate system. The effects of an ''unexpected photopeak, ''zero intensity component, and overlapping peaks on the solution by the various methods were investigated with special emphasis on low-level samples. The most common mathematical methods for resolving a composite gamma-ray spectrum into its components were investigated. Most of these procedures lead to estimates for the concentrations of the different gamma-ray emitters by one of the following methods: (1) The successive elimination of the  More>>
Authors:
DeHaan, A. Jr.; Leventhal, L.; Benson, P. [1] 
  1. Tracerlab, Richmond, CA (United States)
Publication Date:
Oct 15, 1965
Product Type:
Conference
Report Number:
IAEA-SM-61/41
Resource Relation:
Conference: Symposium on Radioisotope Sample Measurement Techniques in Medicine and Biology, Vienna (Austria), 24-28 May 1965; Other Information: 8 refs., 4 tabs., 4 figs.; Related Information: In: Radioisotope Sample Measurement Techniques in Medicine and Biology. Proceedings of the Symposium on Radioisotope Sample Measurement Techniques| 741 p.
Subject:
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; 37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; BINARY MIXTURES; DIGITAL COMPUTERS; GAMMA RADIATION; GAMMA SPECTRA; GAMMA SPECTROMETERS; LEAST SQUARE FIT; RADIOCHEMICAL ANALYSIS; RADIOISOTOPES
OSTI ID:
22131285
Research Organizations:
International Atomic Energy Agency, Vienna (Austria)
Country of Origin:
IAEA
Language:
English
Contract Number:
Contract AT (04-3)-453
Other Identifying Numbers:
Other: ISSN 0074-1884; TRN: XA13M2475086409
Submitting Site:
INIS
Size:
page(s) 169-184
Announcement Date:
Sep 19, 2013

Conference:

Citation Formats

DeHaan, A. Jr., Leventhal, L., and Benson, P. Comparative Study of the Methods Used for the Computer Resolution of Composite Gamma-Ray Spectra; Etude Comparative des Methodes Utilisees pour la Resolution de Spectres Gamma Complexes au Moyen d'un Ordinateur; Sravnitel'noe izuchenie metodov razresheniya sostavnykh gamma-spektrov pri pomoshchi schetno-reshayushchego ustrojstva; Estudio Comparativo de los Metodos Aplicados para Resolver Espectros Gamma Complejos Mediante Calculadoras. IAEA: N. p., 1965. Web.
DeHaan, A. Jr., Leventhal, L., & Benson, P. Comparative Study of the Methods Used for the Computer Resolution of Composite Gamma-Ray Spectra; Etude Comparative des Methodes Utilisees pour la Resolution de Spectres Gamma Complexes au Moyen d'un Ordinateur; Sravnitel'noe izuchenie metodov razresheniya sostavnykh gamma-spektrov pri pomoshchi schetno-reshayushchego ustrojstva; Estudio Comparativo de los Metodos Aplicados para Resolver Espectros Gamma Complejos Mediante Calculadoras. IAEA.
DeHaan, A. Jr., Leventhal, L., and Benson, P. 1965. "Comparative Study of the Methods Used for the Computer Resolution of Composite Gamma-Ray Spectra; Etude Comparative des Methodes Utilisees pour la Resolution de Spectres Gamma Complexes au Moyen d'un Ordinateur; Sravnitel'noe izuchenie metodov razresheniya sostavnykh gamma-spektrov pri pomoshchi schetno-reshayushchego ustrojstva; Estudio Comparativo de los Metodos Aplicados para Resolver Espectros Gamma Complejos Mediante Calculadoras." IAEA.
@misc{etde_22131285,
title = {Comparative Study of the Methods Used for the Computer Resolution of Composite Gamma-Ray Spectra; Etude Comparative des Methodes Utilisees pour la Resolution de Spectres Gamma Complexes au Moyen d'un Ordinateur; Sravnitel'noe izuchenie metodov razresheniya sostavnykh gamma-spektrov pri pomoshchi schetno-reshayushchego ustrojstva; Estudio Comparativo de los Metodos Aplicados para Resolver Espectros Gamma Complejos Mediante Calculadoras}
author = {DeHaan, A. Jr., Leventhal, L., and Benson, P.}
abstractNote = {The resolution of complex mixtures of gamma-ray emitters has been expedited by the use of highly sophisticated gamma-ray spectrometers in association with digital computers. These instruments have now become generally available or easily accessible to technical laboratories. This paper discusses the techniques used in this laboratory to obtain the concentrations of individual gamma-emitting radionuclides in fallout samples and compares the results obtained by the various mathematical methods on composite samples. The computer derived data are compared with results obtained by radiochemical analysis of the sample. Binary mixtures were analysed by methods outlined below and then the analysis was extended to the many component system. A computer method was developed which normalizes gamma-ray spectra to minimize the effect of long-term spectrometer drift and converts the spectrum to an energy co-ordinate system. The effects of an ''unexpected photopeak, ''zero intensity component, and overlapping peaks on the solution by the various methods were investigated with special emphasis on low-level samples. The most common mathematical methods for resolving a composite gamma-ray spectrum into its components were investigated. Most of these procedures lead to estimates for the concentrations of the different gamma-ray emitters by one of the following methods: (1) The successive elimination of the radionuclides with higher energy photopeaks subtracting the pure spectrum from the composite spectrum until it has been resolved; (2) Peak resolution without stripping; (3) The establishment of a set of simultaneous linear equations of the same order as the number of radionuclides in the mixture and its solution; (4) The estimation of the unknown concentrations by the method of least-squares, either conventional or weighted; (5) A combined statistical and least-squares method employing stepwise multiple linear regression, an attempt to integrate decision-making processes into the analysis. Statistical estimates for the errors in the resulting concentration of the radionuclides are provided for each analytical method when they are applied to multicomponent radionuclide mixtures. (author) [French] La resolution du rayonnement de melanges oomplexes d'emetteurs gamma a ete facilitee par l'emploi de spectrometres gamma tres perfectionnes et de calculatrices numeriques. Ces appareils sont maintenant a la disposition de presque tousles laboratoires techniques. Les auteurs etudient les techniques utilisees dans leur laboratoire pour mesurer les concentrations individuelles de differents radionucleides emetteurs gamma dans des echantillons provenant de retombees radioactives et comparent les resultats obtenus par les differentes methodes mathematiques avec des echantillons de composition complexe. Les donnees fournies par l'ordinateur sont comparees avec les resultats obtenus par analyse radiochimique de l'echantillon. Apres avoir analyse des composes binaires au moyen des methodes decrites ci-apres, les auteurs ont etendu l'analyse aux emetteurs composes de nombreux elements. Ils ont mis au point une methode avec ordinateur qui normalise les spectres gamma de maniere a reduire au minimum le glissement a long terme du spectrometre et qui convertit le spectre en une configuration dont l'energie est l'une des coordonnees. Ils etudient par les diverses methodes ci-apres les effets d'un 'pic photoelectrique imprevu ', d'un element d'intensitezero et de la superposition de pics, en particulier dans le cas d'echantillons de faible activite. Les auteurs ont analyse les methodes mathematiques les plus courantes pour la resolution des diverses composantes d'un spectre gamma complexe. La plupart de ces methodes aboutissent a une evaluation des concentrations de differents emetteurs gamma par l'un des procedes suivants: 1. Elimination successive des radionucleides a pic photoelectrique de forte energie, le spectre pur etant extrait du spectre compose jusqu'a resolution; 2. Resolution du pic sans elimination; 3. Etablissement d'un ensemble d'equ'ations lineaires simultanees du meme ordre que le nombre de radionucleides presents dans le melange et solution de ces equations; 4. Evaluation des concentrations non connues par la methode des moindres carres, classique ou ponderee; 5. Combinaison des methodes statistiques et des methodes des moindres carres utilisant la regression lineaire multiple progressive, en s'efforcant d'integrer des processus decisifs dans l'analyse. Pour chaque methode d'analyse appliquee a des melanges de radionucleides, les auteurs fournissent une estimation statistique des erreurs de mesure de la concentration des radionucleides. (author) [Spanish] La resolucion de mezclas complejas de emisores gamma se ha simplificado gracias al empleo de espectrometros gamma muy perfeccionados en asociacion con calculadoras numericas. En la actualidad, los laboratorios pueden en general disponer de estos instrumentos o tener facilmente acceso a ellos. En la memoria se examinan los metodos seguidos en el laboratorio de los autores para determinar la concentracion de cada radionuclido emisor gamma contenido en muestras de precipitaciones radiactivas, y se comparan los resultados obtenidos por los diferentes metodos matematicos aplicables a las muestras compuestas. Los datos proporcionados por las calculadoras se comparan con los resultados obtenidos por analisis radioquimico de la muestra. Se han analizado muestras binarias por los metodos mencionados, operacion que se extendio despues a las mezclas integradas por muchos componentes. Se ha elaborado un metodo de computo que normaliza los espectros gamma para reducir al mfnimo el efecto de la deriva del espectrometro a largo plazo, y representa el espectro segun un sistema de coordenadas, una de las cuales es la energia. Se han investigado los efectos de un 'fotopico imprevisto', de una componente de intensidad cero y de picos superpuestos en la resolucion segun los diferentes metodos, prestando especial atencion a las muestras de baja actividad. Se han estudiado los metodos matematicos de uso mas corriente para resolver en sus componentes un espectro gamma complejo. Con arreglo a ellos, la concentracion de los diferentes emisores gamma se calcula por uno de los siguientes procedimientos: 1. Eliminacion sucesiva de radionuclidos con fotopicos de energia elevada sustrayendo el espectro puro del espectro complejo, hasta su resolucion. 2. Resolucion por picos sin sustraccion, 3. Establecimiento y resolucion de un sistema de ecuaciones lineales simultaneas del mismo grado que el numero de radionuclidos de la muestra. 4. Calculo de las concentraciones por cuadrados minimos, segun el metodo clasico o el ponderado. 5. Combinacion de los metodos estadistico y de cuadrados minimos con regresion lineal multiple gradual, lo que constituye una tentativa de introducir en el analisis los procesos determinantes. Se expone, para cada metodo analitico aplicado a mezclas compuestas por varios radionuclidos, el calculo estadistico de los errores inherentes a las concentraciones halladas. (author) [Russian] Razreshenie slozhnyh smesej gamma-izluchatelej bylo uskoreno blagodarja ispol'zovaniju ochen' slozhnyh gamma- spektrometrov sovmestno s cifrovymi schetno-reshajushhimi ustrojstvami. Jeti pribory poluchili v nastojashhee vremja shirokoe rasprostranenie i stali dostupnymi dlja tehnicheskih laboratorij. Daetsja opisanie metodov, primenjaemyh v laboratorii izotopnyh indikatorov dlja opredelenija koncentracii otdel'nyh gamma-izluchajushhih radioizotopov v probah radioaktivnyh osadkov, i sravnivajutsja rezul'taty, poluchennye s sostavnymi probami na osnovanii razlichnyh matematicheskih metodov. Poluchennye pri pomoshhi schetno-reshajushhego ustrojstva dannye sravnivajutsja s rezul'tatami, poluchennymi posredstvom radiohimicheskogo analiza proby. Opisyvaemymi nizhe sposooami snachala izucheny oinarnye smesi, a zatem rezul'taty jetogo analiza rasprostraneny na mnogokomponentnye sistemy. Vyrabotan metod ispol'zovanija schetno-reshajushhego ustrojstva, normalizujushhij gamma-spektry dlja svedenija k minimumu jeffekta smeshhenija spektrometra, kotoryj projavljaetsja s techeniem vremeni, i prevrashhajushhij spektr v jenergeticheskuju sistemu koordinat. Pri pomoshhi razlichnyh metodov i s osobym uporom na proby s maloj aktivnost'ju issledovalis' jeffekty ''neozhidannogo fotopika'', komponenta nulevoj intensivnosti i perekryvajushhihsja pikov na kachestvo razreshenija. Issledovany naibolee shiroko rasprostranennye matematicheskie metody razlozhenija sostavnyh gamma-spektro v na sostavnye chasti. Bol'shaja chast' jetih metodov vedet k opredeleniju koncentracij razlichnyh gamma-izluchatelej pri pomoshhi odnogo iz sledujushhih sposobov: 1 . Posledovatel'noe iskljuchenie radioizotopov s fotopikami naibol'shih jenergij, dlja chego chistyj individual'nyj spektr vychitaetsja iz sostavnogo spektra vplot' do ego polnogo razreshenija. 2. Razreshenie pika bez otdelenija produktov delenija. 3. Sostavlenie rjada odnovremennyh linejnyh uravnenij, chislo kotoryh ravno chislu vhodjashhih v smes' radioizotopov, i razreshenie jetih uravnenij. 4. Opredelenie neizvestnyh koncentracij po metodu prostyh ili vzveshennyh naimen'shih kvadratov. 5. Sovmeshhenie statisticheskogo metoda s metodom naimen'shih kvadratov putem ispol'zovanija stupenchatoj mnogokratnoj linejnoj regressii, chto javljaetsja popytkoj vkljuchit' v analiz processy rassuzhdenij. Dlja kazhdogo analiticheskogo metoda, v sluchae primenenija ego k mnogosostavnym smesjam radioizotopov, dajutsja statisticheskie ocenki velichiny pogreshnosti, s kotoroj mozhet byt' opredelena ih koncentracija. (author)}
place = {IAEA}
year = {1965}
month = {Oct}
}