Nuclear Experimental Input for Nucleosynthesis F. Montes Joint Institute for Nuclear Astrophysics National Superconducting Cyclotron Laboratory

Size: px

Start display at page:

Download "Nuclear Experimental Input for Nucleosynthesis F. Montes Joint Institute for Nuclear Astrophysics National Superconducting Cyclotron Laboratory"

Sandra Rogers
5 years ago
Views:

1 Nuclear Experimental Input for Nucleosynthesis F. Montes Joint Institute for Nuclear Astrophysics National Superconducting Cyclotron Laboratory Experimental status and prospects proton rich-side: rp-process, vp-process neutron rich side: r-process, incomplete r-process Charge-particle reactions (alpha,n) reactions

νp process r process Mass known Half-life known nothing known rp process stellar

2 Nucleosynthesis processes Most of the heavy elements (Z>30) are formed in neutron capture processes, either the slow (s) or rapid (r) neutroncapture process p process νp process r process Mass known Half-life known nothing known rp process stellar burning Big Bang s process protons neutrons Cosmic Rays Light element primary process LEPP

3 Radioactive beams

4 Nuclear physics experiments - proton-rich Masses Decay rates Reaction rates ORNL α-decay 0 Sn, 96 Cd GSI, MSU Ion traps ANL, GSI, Jyvaskyla Coul. dissociation (GSI,RIKEN) (p,dγ) MSU Ion traps ANL, ISOLDE, MSU (α,p) ANL, ORNL, LLN,CRIB (p,γ) TRIUMF, ORNL (p,p) ANC, ORNL ( 3 He,n) ND Fusion evaporation-γ ANL (d,n) FSU ( 3 He,t) Yale, TUM (p,t),( 4 He, 6 He) Yale, RCNP Mass known < kev Mass known <0 kev Mass uncertain, half-life known seen F. Montes

5 Nuclear physics - reaction rates "v = Probability 8 #µ kt e -EêkT % & ( ) 3 / 2 "Ee Gamow peak se e -EêkT 0 ( ) $E / kt se de Reaction Site T9 E 17F+p nova Al+p 30P+p 30S+α x-ray burst x-ray burst x-ray burst ReA3 new science opportunities E[keV/ u] " E E@MeVD 2J +1 ( ) = #! 2 ( 2J x +1) 2J y +1 ( ) E % E r $ x $ y ( ) 2 + ( $ /2) 2 Measure spins, resonance energies, masses, single particle strengths, g-widths and spectroscopic factors 57 Cu + p Zn 0 +

57Cu(d,n)58Zn 28 segmented crystals (36 segments each) Energy resolution 2.5 kev (FWHM) at 1.33 MeV Peak efficiency 7.2% at 1.

6 Indirect reaction rates measurements 58Zn Particle detection system Cyclotron Laboratory at Michigan State University 58Ni Primary target Be 57Cu Fragment separator Gamma- Ray Energy Tracking Array (GRETINA) Next generation gamma- ray spectrometer 57Cu(d,n)58Zn 28 segmented crystals (36 segments each) Energy resolution 2.5 kev (FWHM) at 1.33 MeV Peak efficiency 7.2% at 1.33 MeV Array peak- to- total ratio 40% at 1.33 MeV Position resolution 2mm (standard deviation) Secondary target CD2 GRETINA gamma- ray detector

7 Indirect measurement: 57 Cu(d,n) 58 Zn Cyclotron Laboratory at Michigan State University Particle detection system 57 Cu(d,n) 58 Zn 58 Zn 58 Ni Primary target Be 57 Cu Fragment separator Secondary target CD 2 GRETINA gamma- ray detector Counts/(7keV) C. Langer, F. Montes et al., PRL 57 Cu+p Energy [kev] 58 Zn

8 ReA3 reaccelerated beam facility Stopped beam area Relocated LEBIT Laser spectroscopy LINAC Experimental stations EBIT charge breeder beam stopping Energy range MeV for 238 U Energy range MeV for 48 Ca Minimum energy spread < 0.5% Beam period 12.5 ns Reaction Site T9 E E[keV/ u] 17F+p nova Al+p x-ray burst Nuclear Astrophysics: key reactions at near-stellar energies Nuclear structure: transfer reactions 30P+p 30S+α x-ray burst x-ray burst

9 ReA3 reaccelerated beam facility ANASEN (LSU/FSU + MSU) (p,p), (p,α), (α,p), (d,p), (d,n), (α,n) for rp/lepp Active Target Time Projection Chamber (MSU,WMU + collaborators) SECAR 4π solid angle, high resolution (ANL,CSM,MSU,LSU,N (3He,d), (d,p) for rp-process D,ORNL) (p,γ) for rp-process ANASEN LENDA SuN JENSA etc Summing NaI (MSU) (p,γ) for p-process The gas target system Gas Target JENSA (CSM,MSU,ND,ORNL) (α,p), (p,γ) for rp/αp-process

10 Neutron-rich nucleosynthesis Elements are created in processes involving different sites and different astrophysical conditions! r process Mass known Half- life known nothing known α process or incomplete r-process protons neutrons

11 Hot r-process Arcones & Martinez-Pinedo 2011 Hot r-process (γ,n) (n,γ) beta decay protons β-decay neutron capture Need: Masses (traps) Half-lives (Si detector stacks, combine with γ-spectroscopy) Neutron capture rates after neutron freeze-out Neutron emission probabilities (neutron detector) Maybe fission and neutrino interaction rates Location of path Sn = T9/5.04 x ( log T9-1.5 log nn) = MeV Seed photodissociation Equilibrium favors waiting points neutrons The evolution takes place under (n,γ)-(γ,n) equilibrium (classical r- process, Seeger, Fowler and Clayton1965, Kratz et al. 1993)

12 Cold r-process Arcones & Martinez-Pinedo 2011 Cold r-process (n,γ) (γ,n) beta decay Competition between beta decay and neutron capture (Blake & Schramm 1976, Wanajo 2007, Janka & Panov 2009) Location of path Sn = 2-4 MeV Need: Neutron capture rates Half-lives Neutron emission probabilities Maybe fission and neutrino interaction rates

13 Mass measurements status (~2011) Mass uncertainty [kev] Rb (37) Kr (36) Br (35) Se (34) As (33) Ge (32) Ga (31) Zn (30) Y (39) Sr (38) < < 0 > 0 Rh (45) Ru (44) Tc (43) Mo (42) Nb (41) Zr (40) In (49) Cd (48) Ag (47) Pd (46) Sb (51) Sn (50) Cs (55) Xe (54) I (53) Te (52) La (57) Ba (56) Pr (59) Ce (58) Eu (63) Sm (62) Pm (61) Nd (60) Ho (67) Dy (66) Tb (65) Gd (64) Tm (69) Er (68) Yb (70)

14 Possible mass measurements next 5 years Rb (37) Kr (36) Br (35) Se (34) As (33) Ge (32) Ga (31) Zn (30) Known masses < 0 kev uncertainty Possible new mass measurements Y (39) Sr (38) Rh (45) Ru (44) Tc (43) Mo (42) Nb (41) Zr (40) In (49) Cd (48) Ag (47) Pd (46) Sb (51) Sn (50) Cs (55) Xe (54) I (53) Te (52) La (57) Ba (56) Pr (59) Ce (58) Eu (63) Sm (62) Pm (61) Nd (60) Ho (67) Dy (66) Tb (65) Gd (64) Tm (69) Er (68) Yb (70) Direct effect on r- process path

15 Ru Pd Masses in the r-process Cd Mo Zr S2n [MeV] r- process path ETFSI- 1 Neutron number

16 Ru Pd Masses in the r-process Cd Mo Zr Diff. in models S2n [MeV] ETFSI- 1 ETFSI-Q (N=82 quenched) Neutron number CARIBU rea

17 Half-life measurements: current and within 5 years Rb (37) Kr (36) Br (35) Se (34) As (33) Ge (32) Ga (31) Zn (30) Known half- lives CARIBU reach Y (39) Sr (38) Rh (45) Ru (44) Tc (43) Mo (42) Nb (41) Zr (40) In (49) Cd (48) Ag (47) Pd (46) Sb (51) Sn (50) Cs (55) Xe (54) I (53) Te (52) La (57) Ba (56) Pr (59) Ce (58) Eu (63) Sm (62) Pm (61) Nd (60) Ho (67) Dy (66) Tb (65) Gd (64) RIKEN measurements Tm (69) Er (68) Yb (70) GSI measurements

18 Other measurements Limit known half-lives N=82 Current reach for (d,p) Z=50 N=50 (a,n) direct measurement TAS: shape ORNL (d,p) measurements Z=28

19 Abundance [a.u]

20 Time scale [s] β - Nuclear reaction time scales (α,n) (n,α) Metal- poor star HD (n,a) (a,n) (n,p) (p,n) (n,g) (g,n) (p,g) (g,p) (n,γ) (γ,n) beta T9 T 9 =3.2 ρ= 5 g/cm 3 (α,n) (n,α) β - (n,γ) protons (γ,n) neutrons

21 Reaction rate alpha potential dependence 94 Sr(a,*n) Reaction Rate Comparison 1 Rate / Baseline Temperature [GK]

22 Reaction rate level density dependence

23 Reaction rate HF code dependence 1.0E+02 Ratio =1 94Sr(a,xn) inclusive 94Sr(a,n)97Zr TALYS/REACLIB 1.0E E E-04 Temperature (GK)

24 Reaction rate: channel - temperature dependence Reaction Rate 1.0E E E E E-04 94Sr(a,n)97Zr 94Sr(a,2n)96Zr 94Sr(a,3n)95Zr 94Sr(a,4n)94Zr 94Sr(a,5n)93Zr 94Sr(a,6n)92Zr 94Sr(a,np)96Y 94Sr(a,nd or 2np)95Y 94Sr(a,3np or 2nd or nt)94y 94Sr(a,4np or 3nd or 2nt)93Y 94Sr(a,5np or 3nt)94Y 94Sr(a,n2p or 3he)95Sr REACLIB Sum 94Sr(a,n) 1.0E E Temperature (GK)

25 Why does it matter? Astrophysical models and conditions can be constrained by observations if nuclear physics is well known Abundance baseline Z=35 (,n)x Z=35 (,n)x1/ baseline Z=38 (,n)x Z=38 (,n)x1/ baseline Z=39 (,n)x Z=39 (,n)x1/ Z=38 (,n)x Z=38 (,n)x1/ Z=39 (,n)x Z=39 (,n)x1/ Ratio abundance change Z=35 (,n)x Z=35 (,n)x1/ Few isotopes relevant for each Z Trajectory dependent Within nuclear physics uncertainties not possible to reach second peak Nuclear physics uncertainties (~ factor ) has similar effect than Ye uncertainty in abundance pattern Z Z Montes, Arcones, Pereira, in preparation

26 Why does it matter? [A/B] 3 Error bar is due to uncertainty in nuclear physics [A/B] = log (Y A /Y B )- log (Y A /Y B ) solar 2 Montes, Arcones, Pereira, in preparation Z=34 Z=35 Z=36 Z=37 Z=38 Z=39 Z=40 [Zr/Sr] Ye=0.43 Ye=0.45 Ye=0.47 [Zr/Y] [Nb/Sr] [Mo/Nb] [Ru/Mo] [Pd/Rh] [Ag/Zr] [Ag/Pd] Difference due to uncertainty in astrophysics conditions Astrophysical models and conditions can be constrained by observations if nuclear physics is well known

27 Why does it matter? [A/B] 3 Error bar is due to uncertainty in nuclear physics [A/B] = log (Y A /Y B )- log (Y A /Y B ) solar 2 Montes, Arcones, Pereira, in preparation Z=34 Z=35 Z=36 Z=37 Z=38 Z=39 Z=40 [Zr/Sr] Ye=0.43 Ye=0.45 Ye=0.47 [Zr/Y] [Nb/Sr] [Mo/Nb] [Ru/Mo] [Pd/Rh] [Ag/Zr] [Ag/Pd] Difference due to uncertainty in astrophysics conditions Astrophysical models and conditions can be constrained by observations if nuclear physics is well known

28 Hansen, Montes, Arcones, submitted to ApJ

29 Why does it matter? [A/B] 3 [A/B] = log (Y A /Y B )- log (Y A /Y B ) solar 2 Montes, Arcones, Pereira, in preparation Z=34 Z=35 Z=36 Z=37 Z=38 Z=39 Z=40 [Zr/Sr] Ye=0.43 Ye=0.45 Ye=0.47 [Zr/Y] [Nb/Sr] [Mo/Nb] [Ru/Mo] [Pd/Rh] [Ag/Zr] [Ag/Pd] Difference due to uncertainty in astrophysics conditions Astrophysical models and conditions can be constrained by observations if nuclear physics is well known

30 (a,n) reaction rates experimental status No experimental knowledge of (α,n) cross sections for n-rich nuclei [except around Z~50] Other (α,n) reactions matter, but 75 Ga can be produced at NSCL and reaccelerated with ReA3 with ~2 kpps

(a,n) proposed measurement Reaccelerated beam impinging on a Helium cell centered within a neutron long-counter Count neutrons with neutron detector and

efficiency & background) provides (α,n) & (α,2n) cross section for the energy range covered by the window (~200keV/u steps) Position sensitivity of IC gives

31 (a,n) proposed measurement Reaccelerated beam impinging on a Helium cell centered within a neutron long-counter Count neutrons with neutron detector and detect unreacted beam or recoil with position-sensitive ionization chamber Ionization chamber provides beam current Neutrons-detected (taking into account efficiency & background) provides (α,n) & (α,2n) cross section for the energy range covered by the window (~200keV/u steps) Position sensitivity of IC gives a redundant measure of reacted/unreacted beam [to help rid of beaminduced background] Energy loss in ionization chamber allows discrimination of stable-contaminants

Facility for Rare Isotope Beams (FRIB) US Nuclear Physics Community s Major New Initiative Project completion in 2020, managed for early completion in

32 Facility for Rare Isotope Beams (FRIB) US Nuclear Physics Community s Major New Initiative Project completion in 2020, managed for early completion in 2018 Key features: 400 kw heavy ion beams Efficient acceleration (multiple charge states) Stopped and reaccelerated beams Large area of nuclei chart accessible

33 Facility for Rare Isotope Beams (FRIB) Different key-regions probe different model aspects when compared to observations FRIB reach for T 1/2, masses, and β-delayed neutron emission N=126 FRIB reach for (d,p) N=82 Critical region probes: Main r-process parameters Production of actinides Critical region: Disentangle r-processes Critical region probes: neutron capture, mass dependence Critical region probes: r-process freezeout behavior Critical region probes: Main r-process parameters

Hydrogen and Helium Burning in Type I X-ray Bursts: Experimental Results and Future Prospects. Catherine M. Deibel Louisiana State University

Hydrogen and Helium Burning in Type I X-ray Bursts: Experimental Results and Future Prospects Catherine M. Deibel Louisiana State University 8/29/14 CGS15 August 25 29, 2014 1 Click Type to I X-Ray edit