Nuclear Reaction Data for Long-Lived Fission Products Susumu Shimoura Center for Nuclear Study the University of Tokyo This work was funded by ImPACT Program of Council for Science, Technology and Innovation (Cabinet Office, Government of Japan). Background for new reaction data ⦁ Nuclear reactions which transmute ))- Long-Lived Fission Products (LLFP) to stable or short lived RI • Recent world-best accelerators (such as RIBF, J-Parc) in Japan enable us to obtain good nuclear data by using new technology in nuclear science. • Good simulation software and database of evaluated nuclear data in Japan Development of new transmutation system Nuclear reactions for nuclear transmutation by Accelerator ⦁ Nuclear reactions which transmute Long-Lived Fission Product (LLFP: 107Pd, 93Zr, 79Se, 135Cs, 126Sn, (129I, 99Tc)) to stable or short lived RI Candidates ⦁ Neutron induced reaction ⦁ Neutron capture ⦁ Neutron knockout ⦁ Negative muon capture reaction ⦁ Fragmentation/Spallation reaction ⦁ Proton/deuteron-induced fusion-like reaction Nuclear reactions for nuclear transmutation ⦁ Nuclear reactions which transmute Long-Lived Fission Product (LLFP) to stable or short lived RI Candidates ⦁ Neutron induced reaction ⦁ Neutron capture (n,γ) AZ → A+1Z ⦁ Neutron knockout (n,2n) AZ → A-1Z , ,(2)(/), b- 107 , () Pd , g ,, , g, b+ () , ,, Neutron capture cross section (Term./Res.) ANNRI (Accurate Neutron-Nucleus Reaction measurement Instrument) LLFP targets (135Cs, (137Cs)) MLF @ J-PARC ANNRI Preliminary Nuclear reactions for nuclear transmutation ⦁ Nuclear reactions which transmute Long-Lived Fission Product (LLFP) to stable or short lived RI Candidates µ- ⦁ Negative muon capture reaction ⦁ Populate highly excited state followed by neutron(s) emission 107Pd Muon capture (@RCNP, J-PARC, RAL) Compound nuclear states10-20 MeV ? A picture oF Muon Nuclear Capture Reactions on 107Pd Target The neutron and g ray emissions are prompt events: DC muon Pygmy resonance (?) n n 2n Muonic atom 3n Delayed g-ray spectrum from µ--107Pd 4 g rays g rays g rays g rays n 103Rh 104Rh 105Rh 106Rh 107Rh 107Pd(µ-, 4n n) 107Pd(µ-, 3n n) 107Pd(µ-, 2n n) 107Pd(µ-, n n) 107Pd(µ-, n) Stable b-g decay b-g decay b-g decay b-g decay The b- decay and the associated g ray emissions are delayed events. : pulsed muon. @J-PARC MUSE facility RI Beam Factory at RIKEN 3 injectors + cascade of 4 cyclotrons several to 345 MeV/nucleon A variety of primary beams ( d(pol) to U ) World highest-intensity RI beams ECR RILAC CSM GARIS & SCRIT GARIS2 RILAC2 SAMURAI AVF ZeroDegree RIPS Rare RI Ring RRC CRIB SRC SLOWRI SHARAQ fRC KISS BigRIPS IRC 8 Experiment in Inverse Kinematics 27,)7+I+9I () )+9@ HIGL@@GFI@E Tagging in @@F@@F FGEIGF@GFIIB@2 8@CGF8@CL@ E@LI@0 9@GFI:IB@ Bρ+TOF+ΔE 041EH +Total Energy 71EH 304E 1EH 852CDC PTEP 2017, 093D03 S. Kawase et al. 45 Z 93Zr @ 105 MeV/u CH2 target run Bρ -6% setting Nb Downloaded from https://academic.oup.com/ptep/article-abstract/2017/9/093D03/4107637 by University of Tokyo Library user on 14 September 2018 September on 14 user Library Tokyo of by University https://academic.oup.com/ptep/article-abstract/2017/9/093D03/4107637 from Downloaded Proton number Zr 40 93 Y Zr Sr Rb Kr 35 30 2.1 2.15 2.2 2.25 2.3 2.35 Mass-to-charge ratio A/Q Fig. 2. Correlation plot of the proton number Z and the mass-to-charge ratio A/Q in the ZeroDegree spectrometer.Fragmentation/Spallation reaction 102 (a) Nb (Z = 41) (b) Zr (Z = 40) (c) Y (Z = 39) σp exp σ exp 1 d 10 σp PHITS 93 σd PHITS Zr@100MeV/u 100 10-1 102 (d) Sr (Z = 38) (e) Rb (Z = 37) (f) Kr (Z = 36) 1 Production cross section (mb) 10 100 10-1 75 80 85 90 75 80 85 90 75 80 85 90 Mass number Fig. 3. Isotopic-production cross section as a function of mass number for each isotope in the experimental acceptance: (a) Nb (Z 41), (b) Zr (Z 40), (c) Y (Z 39), (d) Sr (Z 38), (e) Rb (Z 37), and (f) Kr (Z 36). = = = = = = the CH2 and CD2 targets were extracted by subtracting those of carbon and background deduced from the C-target and empty-target runs. The error bars show only the statistical uncertainties. The 107 systematic uncertainties are from two factors. One is the target thickness, which is less than 2%, and Pd@200MeV/u 4/10 Reaction data with LLFPs by RIBF-ImPACT Energy Experiments Beam lines Settings Purpose [MeV/u] 137Cs Fragmentation/ Pre-ImPACT BigRIPS+ZeroDegree 190 90Sr spallation 107Pd ImPACT in 2015 Fragmentation/ BigRIPS+ZeroDegree 93Zr/90Sr 100/200 spring Spallation/Coulomb 135Cs 93,94Zr 100/200 ImPACT in 2015 Exclusive BigRIPS+SAMURAI autumn 79,80Se measurements 100/200 107Pd Spallation 50 ImPACT in 2016 BigRIPS+ZeroDegree 93Zr Spallation 50 autumn 126,127Sn Spallation/Coulomb 100/200 107Pd 24/30 ImPACT in 2017 p/d induced reaction BigRIPS+OEDO/SHARAQ 93Zr 30 autumn 79,77Se (d,p) for (n,g) surrogate 20 Neutron induced reaction ⦁ Neutron capture ⦁ Direct measurements for thermal to resonance region ⦁ Surrogate reactions (d,p), (“g”,n) for higher energy ⦁ Neutron knockout Eval. From (p,pxn) RIKEN/UT/… (n,γ) (n,xn) Coulex (“γ”,n) TITech/RIKEN/… J-Parc ANNRI (JAEA) Surrogate (d,p) UT/RIKEN/… 1 MeV Evaluated Data from JENDL4 Coulomb dissociation [(“g”,n) reaction] (Beam of fission fragments) + (Pb targets) Coulex cross sections Erel 92 Zr+2n Erel 93 Zr*+n Erel 93 Zr*+n Erel g decay (g,n) 93Zr+n 94Zr->93Zr+n relative energy spectrum Fitting results with the response functions Fitting relative energy spectrum assuming response function 94Zr using TALYS code /MeV] Level density: Back-shifted Fermi mb Gas model [ [mb/keV] g rel /dE dE / sg: previous result by Berman s s d d e e 93 93 Erel( Zr+n) [MeV] Eg( Zr) [keV] RI BeamLow -Factoryenergy at beam RIKEN below 50 MeV/u 3 injectors + cascade of 4 cyclotrons several to 345 MeV/nucleon A variety ofOEDO primary beams Beam ( d(pol) to U- )line World highest-intensity RI beams ECR RILAC CSM GARIS & SCRIT GARIS2 RILAC2 SAMURAI AVF ZeroDegree RIPS Rare RI Ring RRC CRIB SRC SLOWRI SHARAQ fRC KISS BigRIPS IRC Construction was 2 completed infrom Mar T. Uesaka 2017 OEDO Beamline Degrader OEDO OEDO RFD STQ Bore Radius: 120 mm fRF = 18.25 MHz Max. gradient: 14.1 T/m Vmax = 400 kV Gap(H) = 200 mm Combination: L (Z) = 1200 mm 500- 800 -500 mm W(V) = 400 mm Total length: 2700 mm Installed in Mar. 2017. Low-energy nuclear reaction data for LLFP ⦁ Surrogate reactions (d,p) ⦁ Evaluation of (n,xn) from proton/deuteron induced knockout ⦁ Proton/deuteron-induced fusion-like reaction ⦁ New energy-degrading system at RIBF " & R & RF F " Deflector Energy degrader "/% ∆# ∆# # # # #′ RF on #′ "/% # & " & RF off ∆# "/% # & " & Energy compaction by mono-energetic degrader 4.1. Energy compaction of RI beams The energy compactionDegrader of those ions were performed by using two-types of aluminum 107Pd 330.5 MeV/u degraders of the mono-energetic shape: the one is wedge-shaped degraders with a fixed angle determined from the ion-optical design and the other is an angle-variable wedge- Deg F5 shaped degrader107 betweenPd, 79Se 0–40 mr with 3 mm thickness at the center [38], which107Pd, was 79 newlySe developed at CNS. The figure 11 shows a result of the energy compaction method by using angle-variable degrader( BigRIPS system) to obtain 45 MeV/u 79Se beams produced from(SHARAQ) 170 MeV/u. RF HV: 250kV This successfully demonstratedEnergy that a low-energy measurementPhase: 80 deg. RI beam from was obtained TOF by tuning the angle Mom. acc. was set to be 0.1% at F1. E was also controlled by D magnets. 46.3 ± 2.7 172.8 ± 3.4 (w/ FE9 deg.) (w/o FE9 deg.) (MeV) 6mm 79 20mr Se 45 1.9 MeV/u Deg FE9 Mom. acc. was set to be 2% at F1. E controlled by AT degrader system. (MeV) Fig. 11 Energy compaction from 172 MeV/u to 45 MeV/u by a wedged-shape degrader. The red (black) histogram shows the energy distribution of the 79Se beam with (without) the FE9 degrader. The thickness and angle of the degrader was set to be 6 mm and 20 mr, respectively. of the degrader without an aggravation of the energy spread through the energy degrading from 172.8 3.4(σ) MeV/u to 46.3 2.7(σ) MeV/u. Generally it is hard to tune actual ± ± ion transport exactly to the designed one and also a manufacturing of a completely mono- energetic degrader matching to real ion optics is arduous due to an accuracy of energy-loss estimation in the degrader. However, the angle-variable degrader system can be controlled as a mono-energetic degrader with matching to the real ion-optical situation. Therefore, by this degrader system, the ion-optical condition as designed was satisfied against a mismatching of the ion-optical design and the actual setting for the experiment. The performance of this degrader system are detailedly described in Ref. [38]. 4.2. Beam focusing The FE11 focusing through the RFD is demonstrated in Fig. 12. The secondary beam was set for 77Se at 50 MeV/u, but the angle-tuning of the FE9 degrader was not optimized. The 17/21 Beam focusing 79Se at 170MeV/u 79Se at 45MeV/u 107Pd at 170MeV/u 107Pd at 33MeV/u ( BigRIPS production) (FE12) RF HV: 250kV Phase: 80 deg. Effects of RF Deflector Focusing (FE12) RF OFF RF ON All isotopes All isotopes RF ON 107Pd45+ 20mm FE10) [ns] FE10) RF OFF - 79Se 79Se (FWHM) 107Pd44+ TOF(F3 XFE11 [mm] XFE12 [mm] Setup of experiments at low energy 107Pd, 79Se 107Pd, 79Se ( BigRIPS) (SHARAQ) RF HV: 250kV DegraderPhase: 80 deg.