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“Energy & Transmutation of Radioactive Waste“ collaboration workshop Řež, from June 4 up to June 8 1 Nuclear Physics Institute Řež Methodical comments.

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Presentation on theme: "“Energy & Transmutation of Radioactive Waste“ collaboration workshop Řež, from June 4 up to June 8 1 Nuclear Physics Institute Řež Methodical comments."— Presentation transcript:

1 “Energy & Transmutation of Radioactive Waste“ collaboration workshop Řež, from June 4 up to June 8 1 Nuclear Physics Institute Řež Methodical comments to cross-section measurements M.Honusek Nuclear Physics Institute Řež, Czech Republic __________________________________________________________

2 “Energy & Transmutation of Radioactive Waste“ collaboration workshop Řež, from June 4 up to June 8 2 Nuclear Physics Institute Řež Introduction Measurement of gamma spectra using HPGe detector How to obtain the number of atoms produced in reaction using gamma spectra measurements ? Are the databases of Ig correct ? (some examples) Based on my opinion from nuclear structure studies __________________________________________________________

3 “Energy & Transmutation of Radioactive Waste“ collaboration workshop Řež, from June 4 up to June 8 3 Nuclear Physics Institute Řež CS calculation is based on __________________________________________________________ number of target atoms energy and intensity of the beam (spectrum) number of produced atoms measurements of gamma spectra radioactive, reasonable gamma energies and intensities, reasonable T 1/2

4 “Energy & Transmutation of Radioactive Waste“ collaboration workshop Řež, from June 4 up to June 8 4 Nuclear Physics Institute Řež gamma spectra measurement and analysis (E g, relative Ig) using HPGe detectors well known procedure, it is described by many students in Dubna __________________________________________________________ Comment No 1. The term “error” is usually used. What it means? Is it “the estimation of the standard deviation”? Comment No 2. The estimation of the standard deviation of measured Ig is usually ≥ 2 %

5 “Energy & Transmutation of Radioactive Waste“ collaboration workshop Řež, from June 4 up to June 8 5 Nuclear Physics Institute Řež How to obtain the number of atoms produced in reaction using gamma spectra measurements __________________________________________________________ We need T 1/2, decay scheme, intensity balance for each level Beta 100 % 100 % Beta 50 % 50 % gs Usually we go directly to some database and simply calculate number of radioactive atoms. But some problems could appear…

6 “Energy & Transmutation of Radioactive Waste“ collaboration workshop Řež, from June 4 up to June 8 6 Nuclear Physics Institute Řež To obtain decay scheme, we have to (except simple cases) measure g-g coincidences, g-g-time spectra… __________________________________________________________ Intensity balance g g CE Based on g-g coinc Beta ? Transition 1 Transition 2 CE measurement, angular g distribution, g polarization The data are usually not complete (except simple cases)

7 “Energy & Transmutation of Radioactive Waste“ collaboration workshop Řež, from June 4 up to June 8 7 Nuclear Physics Institute Řež __________________________________________________________ Are the databases of Ig, T1/2 … correct ? (some examples) ENSDF http://www-nds.iaea.org/ensdf/ “main” database,http://www-nds.iaea.org/ensdf/ Nucl.Data Sheets Tables of Ig and the multiplication factor (including error) to obtain data in % per decay NUDAT 2 http://www.nndc.bnl.gov/nudat2/ based on ENSDFhttp://www.nndc.bnl.gov/nudat2/ LUND http://nucleardata.nuclear.lu.se/nucleardata/toi/http://nucleardata.nuclear.lu.se/nucleardata/toi/ ! Old data, S.Y.F. Chu, L.P. Ekström and R.B. Firestone, WWW Table of Radioactive Isotopes, database version 2/28/1999 Friendly, simple search, very popular

8 “Energy & Transmutation of Radioactive Waste“ collaboration workshop Řež, from June 4 up to June 8 8 Nuclear Physics Institute Řež __________________________________________________________ In the original paper 177Ta 112.9 keV Ig=22 % based on NUDAT ver. 2.5 Transition 208.4 keV, Ig=2.9 % The databases ENSDF, Lund and NUDAT ver. 2.6 (29.5.2012) ENSDF 112.9 keV Ig=7.24 %, 208.4 keV Ig=0.94 % Lund and NUDAT 2.6 are close to this value The difference is 3 x !

9 “Energy & Transmutation of Radioactive Waste“ collaboration workshop Řež, from June 4 up to June 8 9 Nuclear Physics Institute Řež __________________________________________________________ 91mNb Energy (keV) Ig (%) ENSDF Ig (%) LUND 104.60.5790.539 1204.72.022.9 They are many differences among databases….

10 “Energy & Transmutation of Radioactive Waste“ collaboration workshop Řež, from June 4 up to June 8 10 Nuclear Physics Institute Řež __________________________________________________________ Conclusion The reference to the database used is necessary Prefer ENSDF The errors of gamma intensities should be taken into account


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