Strengths and limitations of the surrogate reaction method to access neutron-induced cross sections of actinides

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1 Strengths and limitations of the surrogate reaction method to access neutron-induced cross sections of actinides P. Marini, Q. Ducasse, B. Jurado, M. Aiche, L. Mathieu, G. Barreau, S. Czajkowski, I. Tsekhanovic CENBG, Gradignan, France T. Tornyi, A Grgen, F. Giacoppo,, M. Guttormsen, A. C. Larsen, T. Renstrom, S. Rose, S. Siem, G. M. Tveten University of Oslo, Oslo, Norway J. Wilson, M. Lebois IPNO, Orsay, France M. Wiedeking ithemba, Somerset West, South Africa O. Serot, G. Boutoux, P. Chau, V. Mot, O. Roig CEA Cadarache and CEA-DAM, France Paola Marini 14 th International conference on nuclear reaction mechanisms Varenna, June 15-19,

Fundamental nuclear properties : o o Reaction mechanisms : from CN formation to direct processes CN decay modeling (fission barrier, transmission coefficients nuclear potential, nuclear structure )

2 Fundamental nuclear properties : o o Reaction mechanisms : from CN formation to direct processes CN decay modeling (fission barrier, transmission coefficients nuclear potential, nuclear structure ) Th Ac U Pu Cf Cm Nuclear energy applications : Development of new advanced nuclear systems ( 235 U only fissile nucleus naturally available) Interest for Astrophysics : Understanding the origins of elements heavier than Fe nuclear data observed isotopic abundances parameters of stellar interior (ρ n, p,t) Mainly short-lived nuclei Surrogate reaction method Paola Marini 14 th International conference on nuclear reaction mechanisms Varenna, June 15-19,

3 J.D. Cramer et H.C. Britt, Nucl. Sci. And Eng. 41 (1970) He d σ ( En) σ ( En) P ( E*) A 1 A A, transfer decay CN decay 243 Cm (t 1/2 =29.1y) 244 Cm* 243 Am (t 1/2 =7370y) Detection of Strengths: ejectile: o Identify the CN o Determine the CN E* reaction products o exit channel Calculated (Optical model calculations) Measured γ emission n emission o access to short-living nuclei (different transfer channels) o simultaneous access to several nuclei on a broad E* range o n free environment o high beam intensity (~10 12 pps) fission Paola Marini 14 th International conference on nuclear reaction mechanisms Varenna, June 15-19,

4 J.D. Cramer et H.C. Britt, Nucl. Sci. And Eng. 41 (1970) He d Assumptions 243 Cm (t 1/2 =29.1y) 244 Cm* 243 Am (t 1/2 =7370y) o Formation of CN (Bohr hypothesis) o The J π distribution of the CN is the same in the two reactions OR the decay of the CN is independent of its J π distribution (Weisskopf-Ewing limit) σ π ( E ) σ ( E, J ) P ( E*, J ) A 1 A π A, transfer decay n CN n decay π J γ emission fission n emission Calculated (Optical model calculations) Test of the assumptions (fission and γ emission) Measured Paola Marini 14 th International conference on nuclear reaction mechanisms Varenna, June 15-19,

5 FISSION on actinides 243 Am( 3 He,α) 242 Am* G. Kessedjian et al., PLB 692, 297 (2010) Paola Marini 14 th International conference on nuclear reaction mechanisms Varenna, June 15-19,

6 FISSION on actinides γ EMISSION on rare earth 243 Am( 3 He,α) 242 Am* 174 Yb( 3 He,pγ) 176 Lu* Only γ and n channels open G. Kessedjian et al., PLB 692, 297 (2010) G. Boutoux, et al., PLB 712 (2012) 319 Paola Marini 14 th International conference on nuclear reaction mechanisms Varenna, June 15-19,

7 FISSION on actinides γ EMISSION on rare earth 243 Am( 3 He,α) 242 Am* 174 Yb( 3 He,pγ) 176 Lu* Only γ and n channels open : P n + P γ = 1 E* S n G. Kessedjian et al., PLB 692, 297 (2010) γ n 175 Lu 9/2 + 7/2 + G. Boutoux, et al., PLB 712 (2012) 319 Optical model TALYS (CEA Bruyères-le-Châtel) From exp. Pγ Different J π distributions populated At E*~S n n emission hindered by spin/parity selectivity of n- emission channel 176 Lu 7 - Paola Marini 14 th International conference on nuclear reaction mechanisms Varenna, June 15-19,

8 FISSION on actinides γ EMISSION on rare earth 243 Am( 3 He,α) 242 Am* 174 Yb( 3 He,pγ) 176 Lu* Only γ and n channels open : P n + P γ = 1 E* S n G. Kessedjian et al., PLB 692, 297 (2010) γ n 175 Lu 9/2 + 7/2 + G. Boutoux, et al., PLB 712 (2012) 319 Optical model TALYS (CEA Bruyères-le-Châtel) From exp. Pγ Different J π distributions populated At E*~S n n emission hindered by spin/parity selectivity of n- emission channel 176 Lu 7 - Simultaneous measurement of fission and γ probabilities on actinides Paola Marini 14 th International conference on nuclear reaction mechanisms Varenna, June 15-19,

9 Ph. D. thesis of Q. Ducasse U + n 239 U* U(d,p) P f Corrected for d break-up (A. Moro Seveille Univ.) P γ U(p,d) 239 U* n-induced x3 P γ surrogate P γ n-induced P f surrogate P f n-induced S n Paola Marini 14 th International conference on nuclear reaction mechanisms Varenna, June 15-19,

10 Ph. D. thesis of Q. Ducasse U + n 239 U* U(d,p) P f Corrected for d break-up (A. Moro Seveille Univ.) P γ U(p,d) 239 U* n-induced x3 P γ surrogate P γ n-induced P f surrogate P f n-induced S n is it explained by statistical model? Paola Marini 14 th International conference on nuclear reaction mechanisms Varenna, June 15-19,

11 Ph. D. thesis of Q. Ducasse P γ U(p,d) 239 U* n-induced x3 statistical model (TALYS, run by CEA evaluator) Probability (J) S n 2 ( J J) 1 2 2σ TALYS π Pγ( E*) e Pγ ( E*, J ) π J 2σ 2π J( 239 U) statistical model (TALYS) P f calculated P f Paola Marini 14 th International conference on nuclear reaction mechanisms Varenna, June 15-19,

12 Ph. D. thesis of Q. Ducasse P γ U(p,d) 239 U* n-induced x3 statistical model (TALYS, run by CEA evaluator) Probability (J) S n 2 ( J J) 1 2 2σ TALYS π Pγ( E*) e Pγ ( E*, J ) π J 2σ 2π J( 239 U) SUMMARY statistical model (TALYS) o γ probability is enhanced by n-emission hindering, i.e. dependence on the populated CN J P f o fission probability not enhanced by n-emission hindering, i.e. independent of the populated CN J o statistical model predicts a higher fission threshold (dependence of fission on J) calculated P f new experiment Paola Marini 14 th International conference on nuclear reaction mechanisms Varenna, June 15-19,

13 Ph. D. thesis of Q. Ducasse 236 U + n 237 U* U( 3 He, 4 He) P f U( 3 He, 4 He) 237 U* n-induced P γ U( 3 He, 4 He) 237 U* n-induced E*( 237 U) MeV S n E*( 237 U) MeV o Setup not adapted for this reaction o Low statistics o No d break-up Same effects!! new dedicated experiment Paola Marini 14 th International conference on nuclear reaction mechanisms Varenna, June 15-19,

14 Ge detectors C6D6 Reaction chamber Sas xy segmented Si telescopes segmented FF detector Ejectile detector : xy segmented Si telescope γ detectors : Ge and C 6 D 6 FF detectors : segmented photovoltaic cells Reduce the uncertainties on P f and P γ on U( 3 He,α) : measure on FF anisotropy Increase the statistics No break-up of 3 He projectile Well defined beam energy Paola Marini 14 th International conference on nuclear reaction mechanisms Varenna, June 15-19,

Ge detectors C6D6 Reaction chamber Sas U( 3 He,d) xy segmented Si telescopes

: Ge and C 6 D 6 FF detectors : segmented photovoltaic cells Reduce the

the statistics No break-up of 3 He projectile Well defined beam energy Paola

15 Ge detectors C6D6 Reaction chamber Sas U( 3 He,d) xy segmented Si telescopes segmented FF detector Ejectile detector : xy segmented Si telescope γ detectors : Ge and C 6 D 6 FF detectors : segmented photovoltaic cells Reduce the uncertainties on P f and P γ on U( 3 He,α) : measure on FF anisotropy Increase the statistics No break-up of 3 He projectile Well defined beam energy Paola Marini 14 th International conference on nuclear reaction mechanisms Varenna, June 15-19,

16 o Surrogate reaction method : only way to access short-lived nuclei o Surrogate reactions vs neutron induced reactions o Fission cross section measurements in good agreement o Gamma emission cross sections in strong disagreement o Strong dependence of gamma emission on the populated CN J distribution o Independence of fission on the populated CN J distribution Need to understand the formation and decay mechanisms of CN in surrogate reactions o These observations are not currently explained within statistical model o New experimental data with better resolution and statistics (April 2015) o Theoretical support is welcome. Paola Marini 14 th International conference on nuclear reaction mechanisms Varenna, June 15-19,

17 Paola Marini 14 th International conference on nuclear reaction mechanisms Varenna, June 15-19,

18 P γ U(p,d) 239 U* n-induced x3 statistical model (TALYS, run by CEA evaluator) Probability (J) S n 2 ( J J) 1 2 2σ TALYS π Pγ( E*) e Pγ ( E*, J ) π J 2σ 2π J( 239 U) Paola Marini 14 th International conference on nuclear reaction mechanisms Varenna, June 15-19,

19 γ 27 NaI inorganic scintillators (γ-ray detection) 8 telescopes of 8 strips ΔE/E 12 C U Ejectiles Fission frag 4 PPACs Fissionfragments detection Paola Marini 14 th International conference on nuclear reaction mechanisms Varenna, June 15-19,

232 Th(n,γ) 0-1.2 232 Th(d,p) absolute J. Wilson et al. (2012) 175 Lu(n,γ) 0-1 174 Yb( 3 He,p) absolute G. Boutoux et al. (2012) 172 Yb(n,γ) 0-1 174 Yb( 3 He,α) absolute G.

20 232 Th(n,γ) Th(d,p) absolute J. Wilson et al. (2012) 175 Lu(n,γ) Yb( 3 He,p) absolute G. Boutoux et al. (2012) 172 Yb(n,γ) Yb( 3 He,α) absolute G. Boutoux et al. (2012) Jutta Escher, et al., Rev. Mod. Phys. 84 (2012) 353 Paola Marini 14 th International conference on nuclear reaction mechanisms Varenna, June 15-19,

21 (d,p) reaction are interesting for inverse kinematics experiments ( RIBs ) CDCC framework d Elastic breakup DWBA formalism d Inelastic breakup Difficult to be distinguished by theory! d Breakup fusion CDCC (Continuum discretized coupled-channel calculation) Antonio Moro and Jin Lei, Univ. of Sevilla, Spain Paola Marini 14 th International conference on nuclear reaction mechanisms Varenna, June 15-19,

Oslo, May , 2015

Oslo, May , 2015 Centre d Etudes Nucléaires de Bordeaux-Gradignan Groupe Aval du Cycle et Energie Nucléaire CEA-Cadarache Q. Ducasse1,6), B. Jurado1), M. Aiche1), L. Mathieu1), T.Tornyi2), A. Goergen2), J. N. Wilson3),