Nuclear Physics for Astrophysics: from the Laboratory to the Stars
Livius Trache
IFIN-HH Bucuresti-Magurele & Cyclotron Institute, Texas A&M University
Texas 2013 Symposium, Dallas, TX, Dec 9-13, 2013 Summary 1. A few contributions of nuclear physics to astrophysics and cosmology • Source of stars’ light • Origin of elements 2. Examples • Big Bang Nucleosynthesis • Confirmation thru BBNucleosynthesis • First determination of Baryon/photon ratio • Number of neutrino types • Number of quarks • Solar neutrino puzzle 3. Indirect methods in NPA with RIBs • Nuclear breakup • Beta-delayed proton decay 4. Some future Nuclei and Nuclear Astrophysics in XX c.
• Edington – nuclear reactions at the origin of stars’ energy • Astronomy becomes astrophysics; Hubble; desc of galaxies • 1930s – Bethe – CNO cycle and the pp chain; the neutron • 1948 – abg primordial reactor (Apr 1, 1948: Alpher, Bethe and Gamow in Phys. Rev.). “The amazing legacy of a wrong paper” (M. Turner) is the beginning of precision cosmology • 1957: B2FH paper (Burbidge, Burbidge, Fowler and Hoyle) and Cameron (Chalk River): BBN and stellar nucleosynthesis • 60s-70s: solar neutrinos detected and solar neutrino puzzle (Pontecorvo, Alvarez… R. Davis Jr., started 1948, Nobel prize 2002) • SM and “The first three minutes” • We, the epigones! – Models – Hydrodynamics – Nuclear data
3 2 Nuclear astrophysics • Nuclear astrophysics – increasingly motivation for NP research: – Nuclei are the fuel of the stars – Origin of chemical elements: nucleosynthesis = a large series of nuclear reactions – & elemental/isotopic abundances are indelible fingerprints of cosmic processes • Big successes of NA: – BBN – quantitative, first determination of baryon/photon ratio, or – parameter free (after CMB) – nr. of neutrino types=3 – Heavier elements created in stars – Solar reactions understood (pp-chains, CNO, solar neutrinos…) – Nucleosynthesis is on-going process! – (quasi-) understand novae, XRB, neutron stars …, but not super-novae … H 73% Solar system abundances (A.G.W. Cameron, 1982) He 24%
Fe peak reflect nuclear properties and stellar environment(s) note odd-even staggering and abundance peaks: Not an equilibrium process!
-(UNDERGROUND LABORATORY) Use of laboratory with natural shield ( underground physics-for instance LUNA experiment at LNGS-Italy )
2H(p,g)3He GRAN SASSO
Stars are cold!
GANOW ENERGY NPA: thousands of reactions
•Direct meas: difficult, stars + fission are cold! M. Smith & E. Rehm barriers ?! •Indirect methods:
•Coulomb dissociation mass, T1/2 •One-nucleon transfer resonances reactions •Breakup reactions site, path?!
•Spectroscopy of mass, T1/2 resonances •Trojan Horse Method •Tests models and param
Two big problems: 1. - reactions in stars involve(d) radioactive nuclei use RNB 2. - very small energies and very small cross sections indirect methods 7 3a Breakup (one-nucleon removal r.)
Momentum distributions → nlj Cross section → ANC (only!!!) Gamma rays → config mixing
Need: Vp-target & Vcore-target and reaction mechanism Calc: F. Carstoiu (Bucharest); Data: see later 8 Example: 7Be(p,g)8B Solar neutrino problem 41H4He+2e++2n p-p chain reaction
pp III chain (0.01%)
The figures are adapted from J. N. Bahcall, 16-Dec-13 Neutrinos from the Sun 9 Example: Summary of the ANC extracted from 8B breakup with different interactions
Data from: F. Negoita et al, Phys Rev C 54, 1787 (1996) B. Blank et al, Nucl Phys A624, 242 (1997) D. Cortina-Gil e a, EuroPhys J. 10A, 49 (2001). R. E. Warner et al. – BAPS 47, 59 (2002). J. Enders e.a., Phys Rev C 67, 064302 (2003) All available breakup cross sections on targets from C to Pb and energies 27- 1000 MeV/u give consistent ANC values!
Summary of results: LT ea, PRL 87, 2001 LT ea, PRC 67, 2004 3 different effective nucleon-nucleon interactions slightly different values 7Be(p,&g )accuracy8B (solar to neutrinosabout 10% : probl .): JLM (blue squares), p-transfer: S17(0)=18.2±1.7 eVb m=1.5 Breakup: “standard” S17(0)=18.7 fm± (black1.9 eVb points) Direct Ray meas (red: trianglesS17(0)=20.8). ±1.4 eVb
10 Astrophysical motivations
The first sources of light: Population III stars novae
T9 ~ 0.2 - 0.4 GK
X-ray Bursts
First stars about 400 million yrs.
T9 ~ 1 - 2 GK
ANC - transfer ANC – nuclear breakup GANIL E491 exp
54 MeV/n
12C(22Mg,22Na)12N Charge exchange (new & unexpected)
23Al→22Mg+p Proton removal (sought) 12 Complementarities: Coulomb and nuclear dissociation Similar results from mirror system: 22Ne+n->23Ne 13C(22Ne,23Ne)12C n-transfer @12MeV/u
assuming Sn=Sp
[46] T. Gomi, T. Motobayashi et al, JPG 31 (2005) 13 3b Decay spectroscopy Resonant Capture
5/2+ a two-step process 23Al Selection rules Energy Coulomb Barrier
Ec
Ep Gp p Gg Radius
Sp 23 23 * 22 Conditions: g+ Mg Mg Na+p 2 23Mg QEC >Sp+2mec 5/2+, 7/2+ 3++1/2+ +0+ J=3/2+, 5/2+, 7/2+ Nuclear Potential Same compound system: 23Mg Resonance strength Resonant contributions to reaction rate: Lower proton32 energies most important, but very difficult: GG 2 2 Er 21Jr p g =g exp g=(2J+1)/(2j+1)(2I+1)g bgb *G res • lower branching 2J 1 2J 1 G p mkT kT pt tot • increased exp difficulties (det windows, background, etc…)
Need energy, Jr and resonance strength 14 Decay spectroscopy Beta- and beta-delayed proton-decay
Explosive H-burning in novae &
IAS in Tz=-3/2 nuclei Isospin mixing GT strength distribution
bottleneck r. in novae 22Na depletion in novae 31Cl→31S* 30P(p,g)31S* 23Al→23Mg* 22Na(p,g)23Mg* & 22Mg(p,g)23Al
15 23Al MARS
In-flight RB production
24Mg 48A MeV
23Al 40A MeV
Purity: 90%, or >99% after en degrader Primary beam 24Mg @ 48A MeV – K500 Cycl Primary target LN2 cooled H2 gas p=1.6-2 atm Intensity: ~ 4000 pps Secondary beam 23Al @ 40.2A MeV First time - very pure & intense 23Al
(p,2n) reaction 16 b decay study of pure RB samples
17 Full disclosure!
22 Background subtracted using decay of Mg (not a proton emitter) 18 Solution: ASTROBOX
emitted proton electrons
E Pollacco (CEA Saclay) proposed: • Gas detector w MICROMEGAS • Low proton energies (~1-200 keV), good resolution (5-10%) • Reduced b background 19 Run0311B: 23Al bp-decay with ASTROBOX
Implantation control Off-beam spectrum
579
866 267 Center IAS?! 234
detector Outer + center
206 keV 206 337
20 21 4 Extreme Light Infrastructure
2006 – ELI on ESFRI Roadmap
ELI-PP 2007-2010 (FP7) ELI-Beamlines (Czech Republic) ELI-Attoseconds (Hungary) ELI-Nuclear Physics (Romania) Project Approved by the European Competitiveness Council (December 2009) ELI-DC (Delivery Consortium): April 2010 Bucharest: June 2013 – civil constr started
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Nuclear Astrophysics - Indirect methods 1. with RIBs: Steps at ELI-NP
• RNB production: mechanism → study production w. spectrometer(s), w. gas-filled separator ?! • RNB separation – momentum achromat + velocity filter ?! • Secondary beam preparation – Filters?! Reacceleration?! • Secondary reaction – target station • Detection – complex array(s): gas, Si, g, PID, position sensitive, … • Extract NS information - difficult theory calc: structure and reactions • (Normalization) - may need absolute values from elsewhere • NA interpretation - theory support again!
• Comparison with direct measurements/ normalization – develop strong program of direct measurements at the 3 MV tandetron
L. Trache, ELI-NP workshop, Bucharest, June 25-26, 2013 24 2. Laser-induced “stellar plasma”?!
• Short-lived plasmas w conditions similar to stellar plasmas?! – Characterization – Nuclear astrophysics: capture reactions on excited states – very imp for quantitative descr of stellar nucleosynthesis, but out of the range of our current experimental possibilities. Can we…?!! – How?! What setups?!
CETAL – 1 PW laser to work in 2014, in Bucharest!!!25
L. Trache, ELI-NP workshop, Bucharest, June 25-26, 2013 Thank you!