Joint Research Centre (JRC)

Transcription

1 1 Joint Research Centre (JRC) Cross section measurements in the fast energy range Arjan Plompen European Commission, Joint Research Centre, Institute for Reference Materials and Measurements

2 Overview 2 Activation cross sections since EAF2009 Preparing for T 25 kev activation measurements at SARAF (and FRANZ) Neutron inelastic scattering Summary

3 History < Experimental work Andreas Fessler, Peter Reimer, Valentina Semkova, Sandor Sudar, Ferenc Cserpak, Syed Qaim, Arjan Plompen Donald Smith 73 reactions 385 data points EAF as the main target library Testing of RIPL

4 Activation methodology with covariances, courtesy Don Smith 4

5 Since Ta, W, Hf 20 reactions 80 cross sections (n,t) reactions 58 Ni, 52 Cr (n,αp) 58 Ni Valentina Semkova 241 Am(n,2n) Christophe Sage (n,t) reactions Antonin Krasa 25 kev 231 Pa(n,g) 232 Pa, Iris Dillmann 197 Au(n,g) 198 Au, w. SOREQ AMS (irradiations IRMM) 56 Fe(n,2n) 55 Fe 58 Ni(n,α) 55 Fe 14 N(n,p) 14 C 204 Pb(n,3n) 202 Pb 238 U(n,3n) 236 U 238 U(n,2n) 237 U 232 Th(n,2n) 231 Th 238 U(n,g) 239 U (earlier: KIT) 232 Th(n,g) 233 Th (earlier: KIT) Toni Wallner, Stephan Winkler, Franz Käppeler, Claudia Lederer VERA, ANSTO, KIT

6 231 Pa(n,γ) 6 I. Dillmann Technische Universität München Excellence Cluster Origin and Structure of the Universe F. Käppeler and S. Walter Forschungszentrum Karlsruhe A. Plompen and V. Semkova IRMM Geel E. Berthoumieux, O. Bouland and F. Gunsing CEA Saclay & Cadarache M. Heil and R. Reifarth GSI Darmstadt

7 Li(p,n) neutron source KIT: Lolita 3.7 MV Van de Graaff accelerator FZK 7 Li(p,n) 7 Be reaction Au(n,γ) norm. E p =1912 kev kt~ 25 kev E p =2284 kev E n,av ~ 511 kev 7 EFNUDAT Uppsala,

8 (Preliminary) results 8 JEFF-3.1: much too high ENDF/B-VII.0: too low JEFF-3.0A/ JENDL-3.3: good agreement except at lowest energy E n (av.)= 36 kev: σ= (2497 ± 12 stat ) mb E n (av.)= 186 kev: σ= (901 ± 12 stat ) mb E n (av.)= 511 kev: σ= (389 ± 10 stat ) mb Iris Dillmann

9 Uncertainties of measurements 9 Methodology Evaluation of measurement data - Guide to the expression of uncertainty in measurement Joint Committee for Guides in Metrology, JCGM 100:2008, (2008) General Systematic Standardized Concepts and terminology Summary of the procedure Illustration

10 Procedure Determine mathematical relation measured quantity and input quantities 2. Determine estimates for inputs 3. Determine standard uncertainties for inputs 4. Determine covariances of input uncertainties 5. Determine output estimate from input estimates 6. Determine the combined standard uncertainties and covariances from the input uncertainties and covariances 7. Report result with standard uncertainties and covariances

11 Activation data evaluation 11 σ Al S I ε f Σ f r n Φ 0 C k Reference cross section Counts for gamma gamma-ray intensity absolute detection efficiency cooling time factor irradiation time factor number of nuclides mean neutron flux correction factors for * low energy neutrons * intensity fluctuations

12 Activation data reporting 12 % uncertainties for components in the activation formula σ Al uncertainty correlations taken from the evaluation ε Al /ε Am uncertainty fully correlated w. neutron energy

13 Activation reporting 13 C. Sage et al., Phys. Rev. C 81 (2010)

14 Preparing for kt 25 kev 14 PRC81_2010_064604SageAm241

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21 197 Au capture cross section 21 Antonin Krasa this workshop

22 Inelastic scattering 22 filters shielding dep U90Mo10 neutron beam E l e c t r o n p i c k o f f collimation Fission chamber Detectors Sample l i n a c external trigger Digitizer Acqiris DC440 signal Neutron time-of-flight with digital processing

23 Inelastic scattering 23 FP3/200m GELINA

24 23 Na(n,n γ) final results Upper limit of energy 3.84 MeV Total inelastic and level inelastic (relies on decay data) 24 All statistics analysed Careful efficiency check gamma-ray detectors Final data delivered to CEA for benchmark testing Report EUR EN. Group cross section < 2.5 %!

25 Total inelastic versus other data and evaluations 25

26 Level cross sections 26

27 186,184,183 W(n,xn γ) cross sections Few results on 186 W P. Scholtes, A. Bacquias, Ph. Dessagne, E. Gasser, M. Kerveno, G.Rudolf, J.C. Th Strasbourg, France A. Plompen, N. Nankov, C. Rouki, M. Staniou, J.C. Drohé Geel, Belgium C. Borcea, D. Deleanu, A.L. Negret Bucharest, Romania 27

28 Preliminary results : observed gamma transitions 28 X X X X X X X : presented

29 Preliminary results : 186 W(n,n γ) cross sections 29 3 transitions in the fondamental band compared to TALYS 1.2 predictions: TALYS predictive power decreases with increasing energy levels.

30 Preliminary results : 186 W(n,2n γ) cross sections 30

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34 Summary 34 Considerable amount of new work is ongoing for higher energies transport and activation studies Some of the work with IRMM involvement was shown Some was passed over AMS results will be shown later this year Fission at IRMM and at n_tof Inelastic by IPHC Strasbourg Capture and transmission (IRMM, n_tof) Some will be shown by Antonin Diamond detectors, Au activation w. Israel, (n,t)

35 Acknowledgement 35 Many thanks to Jura For encouraging experiments at IRMM whichever the ideas were For suggesting new ideas For matching the EAF evaluations to our data For maintaining the critical eye of a stern teacher: Mr. Plompen, how can I trust your experimental data if you are not even able to operate the NEA coffee machine? All the best with your well deserved retirement Or more likely: your temporary unemployment