Introduction Model 1: Uncoupled neutron and gamma emission Model 2: Coupled neutron and gamma emission Conclusion and perspectives A Monte Carlo Simulation of Prompt Gamma Emission from Fission Fragments D. Regnier, O. Litaize, O. Serot CEA Cadarache, DEN/DER/SPRC/LEPH WONDER, 27/09/2012 D. Regnier, O. Litaize, O. Serot - CEA Cadarache, DEN/DER/SPRC/LEPH 1 / 25
Introduction Model 1: Uncoupled neutron and gamma emission Model 2: Coupled neutron and gamma emission Conclusion and perspectives Table of contents Introduction 1 Model 1: Uncoupled neutron and gamma emission 2 Model Results & discussion Model 2: Coupled neutron and gamma emission 3 Model Results & discussion Conclusion and perspectives 4 D. Regnier, O. Litaize, O. Serot - CEA Cadarache, DEN/DER/SPRC/LEPH 2 / 25
Introduction Model 1: Uncoupled neutron and gamma emission Model 2: Coupled neutron and gamma emission Conclusion and perspectives Table of contents Introduction 1 Model 1: Uncoupled neutron and gamma emission 2 Model Results & discussion Model 2: Coupled neutron and gamma emission 3 Model Results & discussion Conclusion and perspectives 4 D. Regnier, O. Litaize, O. Serot - CEA Cadarache, DEN/DER/SPRC/LEPH 3 / 25
Introduction Model 1: Uncoupled neutron and gamma emission Model 2: Coupled neutron and gamma emission Conclusion and perspectives Gamma heating problematic 1 Relative deposited energy 0,8 Photon Deposited Energy Neutron Deposited 0,6 0,4 Core Reflector 0,2 0 0 5 10 15 20 25 30 35 40 Distance from the core center (cm) Figure 2: Perle experiment Figure 1: Relative neutron and photon heating in the Perle experiment (From Phd student S. Ravaux transport calculation with Tripoli-4.7) D. Regnier, O. Litaize, O. Serot - CEA Cadarache, DEN/DER/SPRC/LEPH 4 / 25
Introduction Model 1: Uncoupled neutron and gamma emission Model 2: Coupled neutron and gamma emission Conclusion and perspectives Prompt fission gamma data in evaluated files Two spectra used for all the main fissionning isotopes ( n + 239 Pu, f) : based a on Verbinski et al. measurement (1973) ( n + 235 U, f) : based b on Verbinski et al. measurement (1973) a R. E. Hunter and L. Stewart, LA-4901 (1972) b R. E. Hunter and L. Stewart, LA-4918 (1972) M γ = 7.78 γ /f Figure 3: JEFF-3.1.2 fission gamma spectrum for ( n + 239 Pu, f) D. Regnier, O. Litaize, O. Serot - CEA Cadarache, DEN/DER/SPRC/LEPH 5 / 25
Introduction Model 1: Uncoupled neutron and gamma emission Model 2: Coupled neutron and gamma emission Conclusion and perspectives Prompt fission gamma data in evaluated files Two spectra used for all the main fissionning isotopes ( n + 239 Pu, f) : based a on Verbinski et al. measurement (1973) ( n + 235 U, f) : based b on Verbinski et al. measurement (1973) a R. E. Hunter and L. Stewart, LA-4901 (1972) b R. E. Hunter and L. Stewart, LA-4918 (1972) M γ = 7.17 γ /f Figure 3: JEFF-3.1.2 fission gamma spectrum for ( n + 235 U, f) D. Regnier, O. Litaize, O. Serot - CEA Cadarache, DEN/DER/SPRC/LEPH 5 / 25
Introduction Model 1: Uncoupled neutron and gamma emission Model 2: Coupled neutron and gamma emission Conclusion and perspectives FIFRELIN: A Monte Carlo simulation of fission fragments evaporation Fissioning nucleus T: Figure 4: Compound nucleus (T= nuclear temperature) D. Regnier, O. Litaize, O. Serot - CEA Cadarache, DEN/DER/SPRC/LEPH 6 / 25
Introduction Model 1: Uncoupled neutron and gamma emission Model 2: Coupled neutron and gamma emission Conclusion and perspectives FIFRELIN: A Monte Carlo simulation of fission fragments evaporation Fissioning nucleus p H p L T: T: Figure 4: Figure 5: Fully accelerated Compound nucleus fragments (T= nuclear temperature) D. Regnier, O. Litaize, O. Serot - CEA Cadarache, DEN/DER/SPRC/LEPH 6 / 25
Introduction Model 1: Uncoupled neutron and gamma emission Model 2: Coupled neutron and gamma emission Conclusion and perspectives FIFRELIN: A Monte Carlo simulation of fission fragments evaporation Fissioning nucleus p H p L T: T: Figure 4: Figure 5: Fully Figure 6: Prompt accelerated Compound nucleus neutron emission fragments (T= nuclear temperature) D. Regnier, O. Litaize, O. Serot - CEA Cadarache, DEN/DER/SPRC/LEPH 6 / 25
Introduction Model 1: Uncoupled neutron and gamma emission Model 2: Coupled neutron and gamma emission Conclusion and perspectives FIFRELIN: A Monte Carlo simulation of fission fragments evaporation Fissioning nucleus p H p L T: T: Figure 4: Figure 5: Fully Figure 6: Prompt Figure 7: Prompt accelerated Compound nucleus gamma emission neutron emission fragments (T= nuclear temperature) D. Regnier, O. Litaize, O. Serot - CEA Cadarache, DEN/DER/SPRC/LEPH 6 / 25
Introduction Model 1: Uncoupled neutron and gamma emission Model 2: Coupled neutron and gamma emission Conclusion and perspectives Table of contents Introduction 1 Model 1: Uncoupled neutron and gamma emission 2 Model Results & discussion Model 2: Coupled neutron and gamma emission 3 Model Results & discussion Conclusion and perspectives 4 D. Regnier, O. Litaize, O. Serot - CEA Cadarache, DEN/DER/SPRC/LEPH 7 / 25
Introduction Model 1: Uncoupled neutron and gamma emission Model 2: Coupled neutron and gamma emission Conclusion and perspectives Model 1 Approximation on neutron/gamma competition Entry region for E* E* Primary Fragments Emit neutrons until a lim 1 n n n limit energy is reached, n n E limit = Sn + E rot ( J ) n E(Yrast) Entry region for n γ Secondary Fragments γ } Decay by gamma 2 γ γ statistical γ and/or conversion γ } γ Sn γ discret levels electron emissions. γ γ γ γ J Neutron emission Energy sampled in a Weisskopf spectrum: χ ( ǫ n ) ∝ σ inv ( ǫ n ) ǫ n e − ǫ n / T Total angular momentum: J A − 1 = J A − 1 / 2 � D. Regnier, O. Litaize, O. Serot - CEA Cadarache, DEN/DER/SPRC/LEPH 8 / 25
Introduction Model 1: Uncoupled neutron and gamma emission Model 2: Coupled neutron and gamma emission Conclusion and perspectives Model 1 Gamma emission Energy For one fission fragment E i J i Departure from a known excited 1 i level ( E ∗ i , J i , π i ) dE Decay probabilities calculation: 2 Continuum bound I γ ( i → j ) = Γ γ ( i → j ) (1) Γ γ, tot Experimental levels Γ γ ( i → j ) = f XL ( ǫ γ ) ǫ 2 L + 1 y fluctuation ρ ( E f , J f , π f ) GS (2) Figure 8: Level scheme of the fission fragment Sample one transition 3 Gamma decay until a stable level 4 is reached D. Regnier, O. Litaize, O. Serot - CEA Cadarache, DEN/DER/SPRC/LEPH 9 / 25
Introduction Model 1: Uncoupled neutron and gamma emission Model 2: Coupled neutron and gamma emission Conclusion and perspectives Model 1 Gamma emission Energy For one fission fragment 1 I γ 2 I γ 3 I γ 4 I γ 5 I γ E i J i Departure from a known excited 1 i level ( E ∗ i , J i , π i ) dE Decay probabilities calculation: 2 Continuum bound I γ ( i → j ) = Γ γ ( i → j ) (1) Γ γ, tot Experimental levels Γ γ ( i → j ) = f XL ( ǫ γ ) ǫ 2 L + 1 y fluctuation ρ ( E f , J f , π f ) GS (2) Figure 8: Level scheme of the fission fragment Sample one transition 3 Gamma decay until a stable level 4 is reached D. Regnier, O. Litaize, O. Serot - CEA Cadarache, DEN/DER/SPRC/LEPH 9 / 25
Introduction Model 1: Uncoupled neutron and gamma emission Model 2: Coupled neutron and gamma emission Conclusion and perspectives Model 1 Gamma emission Energy For one fission fragment E i J i Departure from a known excited 1 i level ( E ∗ i , J i , π i ) dE E γ Decay probabilities calculation: 2 Continuum bound I γ ( i → j ) = Γ γ ( i → j ) (1) Γ γ, tot Experimental levels Γ γ ( i → j ) = f XL ( ǫ γ ) ǫ 2 L + 1 y fluctuation ρ ( E f , J f , π f ) GS (2) Figure 8: Level scheme of the Sample one transition fission fragment 3 Gamma decay until a stable level 4 is reached D. Regnier, O. Litaize, O. Serot - CEA Cadarache, DEN/DER/SPRC/LEPH 9 / 25
Introduction Model 1: Uncoupled neutron and gamma emission Model 2: Coupled neutron and gamma emission Conclusion and perspectives Model 1 Gamma emission Energy For one fission fragment E i J i Departure from a known excited 1 i level ( E ∗ i , J i , π i ) dE Decay probabilities calculation: 2 Continuum bound I γ ( i → j ) = Γ γ ( i → j ) 3 I γ (1) Γ γ, tot Experimental 2 I γ 1 I γ levels Γ γ ( i → j ) = f XL ( ǫ γ ) ǫ 2 L + 1 y fluctuation ρ ( E f , J f , π f ) GS (2) Figure 8: Level scheme of the fission fragment Sample one transition 3 Gamma decay until a stable level 4 is reached D. Regnier, O. Litaize, O. Serot - CEA Cadarache, DEN/DER/SPRC/LEPH 9 / 25
Introduction Model 1: Uncoupled neutron and gamma emission Model 2: Coupled neutron and gamma emission Conclusion and perspectives Model 1 Gamma emission Energy For one fission fragment E i J i Departure from a known excited 1 i level ( E ∗ i , J i , π i ) dE Decay probabilities calculation: 2 Continuum bound I γ ( i → j ) = Γ γ ( i → j ) (1) Γ γ, tot E γ Experimental levels Γ γ ( i → j ) = f XL ( ǫ γ ) ǫ 2 L + 1 y fluctuation ρ ( E f , J f , π f ) GS (2) Figure 8: Level scheme of the fission fragment Sample one transition 3 Gamma decay until a stable level 4 is reached D. Regnier, O. Litaize, O. Serot - CEA Cadarache, DEN/DER/SPRC/LEPH 9 / 25
Recommend
More recommend
