Fission Cross Sections and Nuclear Level Densities Analysis
Explore the impact of nuclear level densities on fission cross sections through empirical observations and calculations. Roberto Capote from IAEA delves into the importance of proper descriptions of fission channels and the minimum requirements in physics. Learn about the role of collective effects, damping, and more in fission processes.
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Fission Cross Sections, differential XS and Nuclear Level Densities Roberto Capote, Deputy Section Head 1RCM of the IAEA CRP on Nuclear Level Densities 24-28 March, 2025, Vienna, IAEA HQ, Austria NAPC - Nuclear Data Section, IAEA, Vienna, Austria Roberto Capote, IAEA Nuclear Data Section e-mail: R.CapoteNoy@iaea.org Web: http://www-nds.iaea.org 1 R.CapoteNoy@iaea.org http://www-nds.iaea.org
Minimum requirements: NLD PHYSICS 1. Consideration of shell structure 2. Pairing effects 3. Collective effects (triaxiality critical!) 4. Damping of collective and shell effects EMPIRICAL OBSERVATIONS 1. Constant temperature Roberto Capote, IAEA Nuclear Data Section e-mail: R.CapoteNoy@iaea.org Web: http://www-nds.iaea.org 2 1RCM of the IAEA CRP on Nuclear Level Densities 24-28 March, 2025, Vienna, IAEA HQ, Austria R.CapoteNoy@iaea.org http://www-nds.iaea.org
NLD impact on (n,f) calcs. Collective effects & damping Roberto Capote, IAEA Nuclear Data Section e-mail: R.CapoteNoy@iaea.org Web: http://www-nds.iaea.org 3 1RCM of the IAEA CRP on Nuclear Level Densities 24-28 March, 2025, Vienna, IAEA HQ, Austria R.CapoteNoy@iaea.org http://www-nds.iaea.org
Fission XS calcs. as NLD test ENDF/B-VIII.0 (IAEA CIELO evaluation) 238U(n,f) 238U fiss. 237U fiss. 239U fiss. D. Brown et al, NDS 148(2018)1; A. Carlson et al, NDS 148(2018) 143; RC et al, NDS 148(2018) 254 Roberto Capote, IAEA Nuclear Data Section e-mail: R.CapoteNoy@iaea.org Web: http://www-nds.iaea.org 4 1RCM of the IAEA CRP on Nuclear Level Densities 24-28 March, 2025, Vienna, IAEA HQ, Austria R.CapoteNoy@iaea.org http://www-nds.iaea.org
Why is important to describe fission? -> Proper description of competing channels: (n,n ); (n, ); (n,2n); (n,n ) (n,f) (n, ) (n,2n) RC et al, Nucl. Data Sheets 148(2018) 254 Roberto Capote, IAEA Nuclear Data Section e-mail: R.CapoteNoy@iaea.org Web: http://www-nds.iaea.org 5 1RCM of the IAEA CRP on Nuclear Level Densities 24-28 March, 2025, Vienna, IAEA HQ, Austria R.CapoteNoy@iaea.org http://www-nds.iaea.org
Fission XS calcs. as NLD test ENDF/B-VIII.0 (IAEA CIELO evaluation) 235U(n,f) 235U fiss. 234U fiss. 236U fiss. D. Brown et al, NDS 148(2018)1; A. Carlson et al, NDS 148(2018) 143; RC et al, NDS 148(2018) 254 Roberto Capote, IAEA Nuclear Data Section e-mail: R.CapoteNoy@iaea.org Web: http://www-nds.iaea.org 6 1RCM of the IAEA CRP on Nuclear Level Densities 24-28 March, 2025, Vienna, IAEA HQ, Austria R.CapoteNoy@iaea.org http://www-nds.iaea.org
Fission XS calcs. as NLD test ENDF/B-VIII.1 (INDEN/LANL/LLNL evaluation) 239Pu(n,f) 240Pu fiss. 239Pu fiss. 238Pu fiss. G. Nobre et al, NDS XXX(2025)X; A. Carlson et al, NDS 148(2018) 143 Roberto Capote, IAEA Nuclear Data Section e-mail: R.CapoteNoy@iaea.org Web: http://www-nds.iaea.org 7 1RCM of the IAEA CRP on Nuclear Level Densities 24-28 March, 2025, Vienna, IAEA HQ, Austria R.CapoteNoy@iaea.org http://www-nds.iaea.org
Collective enhancement: RIPL RIPL-3 paper, Nucl. Data Sheets 110(2009)3107 Roberto Capote, IAEA Nuclear Data Section e-mail: R.CapoteNoy@iaea.org Web: http://www-nds.iaea.org 8 1RCM of the IAEA CRP on Nuclear Level Densities 24-28 March, 2025, Vienna, IAEA HQ, Austria R.CapoteNoy@iaea.org http://www-nds.iaea.org
Rotational damping NLD RIPL-3 paper, Nucl. Data Sheets 110(2009)3107 Roberto Capote, IAEA Nuclear Data Section e-mail: R.CapoteNoy@iaea.org Web: http://www-nds.iaea.org 9 1RCM of the IAEA CRP on Nuclear Level Densities 24-28 March, 2025, Vienna, IAEA HQ, Austria R.CapoteNoy@iaea.org http://www-nds.iaea.org
Differential data: DE, DAE (EXFOR) CN dominated emission spectra are ideal for testing NLD shape Roberto Capote, IAEA Nuclear Data Section e-mail: R.CapoteNoy@iaea.org Web: http://www-nds.iaea.org 10 1RCM of the IAEA CRP on Nuclear Level Densities 24-28 March, 2025, Vienna, IAEA HQ, Austria R.CapoteNoy@iaea.org http://www-nds.iaea.org
EXFOR search: Ep=6.8,7.8,8.8 MeV Roberto Capote, IAEA Nuclear Data Section e-mail: R.CapoteNoy@iaea.org Web: http://www-nds.iaea.org 11 1RCM of the IAEA CRP on Nuclear Level Densities 24-28 March, 2025, Vienna, IAEA HQ, Austria R.CapoteNoy@iaea.org http://www-nds.iaea.org
56Fe(a,n)59Ni neutr. emiss. 93Nb(a,n)96Tc neutr. emiss. 115In(a,n)118Sb neutr. emiss. Zhuravlev et al, Conference ISINN-6, p.151 (1998), available in EXFOR pdf Nuclear level density and spin out-off parameter for nuclei of Ni-59, Tc-96, Sb-118 from differential neutron emission cross sections of (p,n) and ( ,n) reaction. Roberto Capote, IAEA Nuclear Data Section e-mail: R.CapoteNoy@iaea.org Web: http://www-nds.iaea.org 12 1RCM of the IAEA CRP on Nuclear Level Densities 24-28 March, 2025, Vienna, IAEA HQ, Austria R.CapoteNoy@iaea.org http://www-nds.iaea.org
Summary Proposed to be studied: Validation of collective enhancement in new NLD Rotational/vibrational damping in (n,f) calcs. For NLD testing use neutron emission spectra at low excitation energies Roberto Capote, IAEA Nuclear Data Section e-mail: R.CapoteNoy@iaea.org Web: http://www-nds.iaea.org 13 1RCM of the IAEA CRP on Nuclear Level Densities 24-28 March, 2025, Vienna, IAEA HQ, Austria R.CapoteNoy@iaea.org http://www-nds.iaea.org
