Abstract
Results are presented for absolute neutron activation analysis using the zirconium double flux monitor method. With this procedure the fluxes, {Phi}{sub th} and {Phi}{sub epi}, are measured with zirconium wires, which are irradiated together with each set of samples. The form factors of epithermal neutron spectra (a-values) of the irradiation facilities used were measured only once or they are only occasionally checked, so that comparatively large uncertainties have to be considered. The errors of the analytical results as far as they are caused by errors of {alpha} are calculated by comparing results obtained with true {alpha}-values with those obtained with erroneous {alpha}-values. Additionally, the case of no {alpha}-correction is investigated. The calculations are carried out for irradiation facilities at the reactors FRJ-2, FRM and HFR, which have different flux ratios and {alpha}-values and, therefore, the influence of uncertainties of {alpha} has different effects on the errors of the analytical results. With most reactions the error propagation factors are {<=} 1, so that errors of the results, as far as they are caused by errors of {alpha}, are negligible compared to other, unavoidable uncertainties of procedures of trace element analysis. With some few reactions, however, for the calculation of appropriate corrections
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Citation Formats
Erdtmann, G.
Errors of absolute methods of reactor neutron activation analysis caused by non-1/E epithermal neutron spectra. The influence of the error of {alpha} when using the zirconium double-monitor method.
Germany: N. p.,
1992.
Web.
Erdtmann, G.
Errors of absolute methods of reactor neutron activation analysis caused by non-1/E epithermal neutron spectra. The influence of the error of {alpha} when using the zirconium double-monitor method.
Germany.
Erdtmann, G.
1992.
"Errors of absolute methods of reactor neutron activation analysis caused by non-1/E epithermal neutron spectra. The influence of the error of {alpha} when using the zirconium double-monitor method."
Germany.
@misc{etde_10128464,
title = {Errors of absolute methods of reactor neutron activation analysis caused by non-1/E epithermal neutron spectra. The influence of the error of {alpha} when using the zirconium double-monitor method}
author = {Erdtmann, G}
abstractNote = {Results are presented for absolute neutron activation analysis using the zirconium double flux monitor method. With this procedure the fluxes, {Phi}{sub th} and {Phi}{sub epi}, are measured with zirconium wires, which are irradiated together with each set of samples. The form factors of epithermal neutron spectra (a-values) of the irradiation facilities used were measured only once or they are only occasionally checked, so that comparatively large uncertainties have to be considered. The errors of the analytical results as far as they are caused by errors of {alpha} are calculated by comparing results obtained with true {alpha}-values with those obtained with erroneous {alpha}-values. Additionally, the case of no {alpha}-correction is investigated. The calculations are carried out for irradiation facilities at the reactors FRJ-2, FRM and HFR, which have different flux ratios and {alpha}-values and, therefore, the influence of uncertainties of {alpha} has different effects on the errors of the analytical results. With most reactions the error propagation factors are {<=} 1, so that errors of the results, as far as they are caused by errors of {alpha}, are negligible compared to other, unavoidable uncertainties of procedures of trace element analysis. With some few reactions, however, for the calculation of appropriate corrections an accurate knowledge of {alpha} is necessary. (orig.). [Deutsch] Weil die Berechnung der Fehlerfortpflanzung fuer die Fehler der Formfunktion epithermischer Neutronenspektren {alpha} etwas kompliziert ist, wird sie selten ausgefuehrt und die Auswirkungen der Fehler von {alpha} werden falsch eingeschaetzt. Es wurden Rechenprogramme entwickelt mit denen diese Fehler fuer alle wichtigen (n,{gamma})-Reaktionen und einige Bestrahlungseinrichtungen ausgerechnet werden koennen. Ergebnisse werden vorgestellt, die sich bei Anwendung der Zirkonium-Doppelmonitor-Methode ergeben. Dabei werden die Flussdichten der thermischen und der epithermischen Neutronen ueber die Aktivierung der Zirkoniumisotope {sup 94}Zr und {sup 96}Zr bestimmt. {alpha} wird fuer eine bestimmte Bestrahlungseinrichtung nur einmal oder nur gelegentlich bestimmt und die Unsicherheiten, die sich aus eventuellen zeitlichen oder raeumlichen Veraenderungen ergeben, werden als Fehler von {alpha} bei der Fehlerrechnung fuer das analytische Ergebnis beruecksichtigt. Die Berechnungen wurden fuer Bestrahlungseinrichtungen an den Forschungsreaktoren FRJ-2, FRM und HFR ausgefuehrt. (orig.).}
place = {Germany}
year = {1992}
month = {Aug}
}
title = {Errors of absolute methods of reactor neutron activation analysis caused by non-1/E epithermal neutron spectra. The influence of the error of {alpha} when using the zirconium double-monitor method}
author = {Erdtmann, G}
abstractNote = {Results are presented for absolute neutron activation analysis using the zirconium double flux monitor method. With this procedure the fluxes, {Phi}{sub th} and {Phi}{sub epi}, are measured with zirconium wires, which are irradiated together with each set of samples. The form factors of epithermal neutron spectra (a-values) of the irradiation facilities used were measured only once or they are only occasionally checked, so that comparatively large uncertainties have to be considered. The errors of the analytical results as far as they are caused by errors of {alpha} are calculated by comparing results obtained with true {alpha}-values with those obtained with erroneous {alpha}-values. Additionally, the case of no {alpha}-correction is investigated. The calculations are carried out for irradiation facilities at the reactors FRJ-2, FRM and HFR, which have different flux ratios and {alpha}-values and, therefore, the influence of uncertainties of {alpha} has different effects on the errors of the analytical results. With most reactions the error propagation factors are {<=} 1, so that errors of the results, as far as they are caused by errors of {alpha}, are negligible compared to other, unavoidable uncertainties of procedures of trace element analysis. With some few reactions, however, for the calculation of appropriate corrections an accurate knowledge of {alpha} is necessary. (orig.). [Deutsch] Weil die Berechnung der Fehlerfortpflanzung fuer die Fehler der Formfunktion epithermischer Neutronenspektren {alpha} etwas kompliziert ist, wird sie selten ausgefuehrt und die Auswirkungen der Fehler von {alpha} werden falsch eingeschaetzt. Es wurden Rechenprogramme entwickelt mit denen diese Fehler fuer alle wichtigen (n,{gamma})-Reaktionen und einige Bestrahlungseinrichtungen ausgerechnet werden koennen. Ergebnisse werden vorgestellt, die sich bei Anwendung der Zirkonium-Doppelmonitor-Methode ergeben. Dabei werden die Flussdichten der thermischen und der epithermischen Neutronen ueber die Aktivierung der Zirkoniumisotope {sup 94}Zr und {sup 96}Zr bestimmt. {alpha} wird fuer eine bestimmte Bestrahlungseinrichtung nur einmal oder nur gelegentlich bestimmt und die Unsicherheiten, die sich aus eventuellen zeitlichen oder raeumlichen Veraenderungen ergeben, werden als Fehler von {alpha} bei der Fehlerrechnung fuer das analytische Ergebnis beruecksichtigt. Die Berechnungen wurden fuer Bestrahlungseinrichtungen an den Forschungsreaktoren FRJ-2, FRM und HFR ausgefuehrt. (orig.).}
place = {Germany}
year = {1992}
month = {Aug}
}