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Nuclear Physics at Rare-Isotope Facilities in North-America

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  1. Nuclear Physics at Rare-Isotope Facilities in North-America IUPAP WG.9 Symposium 2-3 July, 2010 Bradley M. Sherrill Michigan State University

  2. The Science of Rare Isotopes Properties of nuclei (nuclear structure) Develop a predictive model of nuclei and their interactions Many-body quantum problem: intellectual overlap to mesoscopicscience, quantum dots, atomic clusters, etc. Nuclear processes in the universe Chemical history of the universe, (explosive) nucleo-synthesis Properties of neutron stars, EOS of asymmetric nuclear matter Tests of fundamental symmetries Effects of symmetry violations are amplified in certain nuclei Societal applications and benefits Bio-medicine, energy, material sciences, national security

  3. Nuclei matter • The atomic nucleus is a significant intellectual challenge with three of nature’s four forces having a significant role. Can we construct a comprehensive and predictive model of its properties? How do we relate that model to QCD? Surprises are still likely. • The properties of nuclei are relevant to other sciences, e.g., neutrinoless double-beta decay the rate is related to nuclear matrix elements • Wealth of quantum phenomena of interest to related sciences • Mesoscopic systems • Simple patterns in complex systems (Symmetry phases) • Connections to atomic clusters • Open quantum system • Nuclear reactions • Efimov states • …

  4. Properties of rare isotopes are essential in determining NN and NNN potentials • Neutron rich nuclei were key in determining the isospin dependence of 3-body forces and the development of IL-2R from UIX • New data on exotic nuclei continues to lead to refinements in the interactions, e.g., strength of NN and NNN interactions • EFT developments, LQCD and even computational power are providing insight for ab initio theories, but they need grounding in data S. Pieper B.Wiringa, et al.

  5. Application of GFMC technique to reactions of nuclei • Resonance states in 5He (n+4He) Nollett, et al, PRL 2007; motivated by BBN modeling

  6. Theory Road Map: Comprehensive Model of Nuclear Structure and Reactions • Theory Road Map – comprehensive description of the atomic nucleus • Ab initio models – study of neutron-rich, light nuclei helps determine the force to use in models (measurement of sensitive properties for N=14, 16 nuclei) • Configuration-interaction theory; study of shell and effective interactions (study of key nuclei such as 54Ca, 60Ca, 122Zr) • The universal energy density functional (DFT) – determine parameters (broad view of mass surface, BE(2)s, BE(4)s, fission barrier surface, etc.) • The role of the continuum and reactions and decays of nuclei (halo studies up to A ~100) • IMPORTANT: Understand and select the most sensitive measurements Energy density functional Configuration interaction Ab initio Continuum Relationship to QCD (LQCD)

  7. The Challenge: Understand the Chemical History of the Universe • Understanding the chemical history of the universe and what it tells us about individual stars, the first stars, galactic evolution • The abundance of elements tell us about the history of events prior to stellar formation. How can we extract that information? Solar system abundances Lodders (2003)

  8. Forefront of Observational Astronomy: High Resolution Telescopes Hubble Space • The measurement of elemental abundances is at the forefront of astronomy using large telescopes • Large mirrors enable high resolution spectroscopic studies in a short time (Hubble, LBT, Keck, …) • Surveys have provided large data sets (SDSS, LAMOS, SkyMap, HERMES, LSST, Gaia, …) • Future missions: JWST - “is specifically designed for discovering and understanding the formation of the first stars and galaxies, measuring the geometry of the Universe and the distribution of dark matter, investigating the evolution of galaxies and the production of elements by stars, and the process of star and planet formation.” Large Binocular Telescope

  9. Search for the ashes of the first stars • Less Fe implies earlier star formation • Measured with high resolving power telescopes, Hubble, Keck, LBT, etc. • The process that makes Ba must be different from the main process that makes Fe • The [Ba/Fe] pattern is not understood Logarithmic ratio of abundances relative the Sun

  10. There are a number of nucleosynthesis processes • Big Bang Nucleosynthesis • pp-chain • CNO cycle • Helium, C, O, Ne, Si burning • s-process • r-process • rp-process • νp – process • p – process • α - process • fission recycling • Cosmic ray spallation • pyconuclear fusion • + others • Green – rare isotopes are necessary for accurate modeling of this process

  11. Tests of Nature’s Fundamental Symmetries • Angular correlations in β-decay and search for scalar currents • Mass scale for new particle comparable with LHC • 6He and 18Ne at 1012/s • Electric Dipole Moments • 225Ac, 223Rn, 229Pa (30,000 more sensitive than 199Hg; I > 1010/s) • Parity Non-Conservation in atoms • weak charge in the nucleus (francium isotopes; 109/s) • Unitarity of CKM matrix • Vud by super allowed Fermi decay • Probe the validity of nuclear corrections e γ Z 212Fr

  12. Rare Isotopes For Society • Isotopes for medical research • Examples of isotopes projected to have demand much greater than supply: 47Sc, 62Zn, 64Cu, 67Cu, 68Ge, 149Tb, 153Gd, 168Ho, 177Lu, 188Re, 211At, 212Bi, 213Bi, 223Ra (DOE Isotope Workshop) • -emitters 149Tb, 211At: potential treatment of metastatic cancer • Cancer therapy of hypoxic tumors based on 67Cu possible is a source would be available • Nuclear power (nuclear data is needed to optimize reactor design) • Reaction rates important for stockpile stewardship and nuclear power – related to astrophysics network calculations • Determination of extremely high neutron fluxes by activation analysis • Rare isotope samples for (n,g), (n,n’), (n,2n), (n,f) e.g. 88,89Zr • Same technique important for astrophysics • More difficult cases studied via surrogate reactions (d,p), (3He,axn) … • Tracers for Geology (32Si), Condensed Matter (8Li), material studies, … • Special isotopes for homeland security applications (β-delayed neutron emitters to calibrate detectors, etc.)

  13. Nuclear Chart in 1966 The availability of rare isotopes over time Less than 1000 known isotopes Available today New territory to be explored with next-generation RIB facilities about 3000 known isotopes

  14. What New Nuclides Will the Next Generation Facilities Produce? • FRIB will produce more than 1000 NEW isotopes at useful rates (4500 available for study; compared to 1700 now) • Theory is key to making the right measurements • Exciting prospects for study of nuclei along the drip line to mass 120 (compared to 24) • Production of most of the key nuclei for astrophysical modeling • Harvesting of unusual isotopes for a wide range of applications Rates are available at http://groups.nscl.msu.edu/frib/rates/

  15. Rare Isotope Production Techniques using Accelerators • Target spallationand fragmentation by light ions (Used by TRIUMF, HRIBF) • Neutron or photon induced fission (TRIUMF) • In-flight Separation following projectile fragmentation/fission (Used by FRIB) Target/Ion Source beam Post Acceleration Accelerator Neutrons/Photons target Post Acceleration Accelerator beam Accelerator Beam Beams used without stopping target Fragment Separator Post Acceleration Gas catcher/ solid catcher + ion source

  16. Rare Isotope Facilities in North America • Notre Dame University – in-flight light ions • Florida State RESOLUTE – in-flight light and mid-mass ions • Texas A&M Upgrade – ISOL, Gas Catcher, in-flight, accelerated to 50 MeV/u • ANL CARIBU – Cf fission source, in-flight light and mid-mass ions • ORNL HRIBF – ISOL production by 40 MeV light ions; fission fragments • NSCL – 100 MeV/u in-flight ions • TRIUMF ISAC I and II, ARIEL – megawatt class photo fission source, ISOL beams to 8 MeV/u • FRIB – 400 kW, 200 MeV/u in-flight separation, gas stopping, reacceleration to 20 MeV/u

  17. Solenoid 1 Magnetic Spectrograph Target Position Solenoid 2 RF-Resonator RF-Resonator Magnetic Spectrograph Mass selectionslits Production target Experiment RESOLUT: a newradioactive beam facility at FSU • In-flight production of radioactive beams in inverse kinematics • Combination of Superconducting RF-Resonator with high acceptance magnetic Spectrograph to create mass spectrometer

  18. Study of light exotic nuclei through resonance reactions at RESOLUT(G. Rogachev et al.) Excitation function of elastic (top) to inelastic p+7Be scattering (bottom), showing the presence of additional resonances in 8B, observed throughinelastic scattering only Excitation functions of elastic (top) to inelastic p+7Be scattering (bottom) at various angles, R-matrix fit fit with additional resonances included.

  19. T-REX [TAMU Reaccelerated Exotics]

  20. Science accessible with the TAMU upgrade • Nuclear Astrophysics – indirect techniques • Nuclear Structure – transfer reactions, g spectroscopy, … • Fundamental Interactions – trapping expts. • Dynamics and Thermodynamics – N/Z degrees of freedom

  21. Projected Beam Intensities from LIG after K500 Assuming 14 mA beam, realistic LIG, CBECR, transport and K500 extraction efficiencies

  22. Examples of reaccelerated beams produced in DIC: t1/2>100ms Calculation details in poster by G. Souliotis

  23. CARIBU gives access to exotic beams not available elsewhere. Physics with beams from CARIBU (1 & 2 nucleon transfer reactions) needs the new energy regime opened by the Energy Upgrade (12 MeV/u) . Solenoid Spectrometer greatly expands the effectiveness of both the fission fragment beams and the existing in-flight RIB program at these higher energies. These three projects combine to form a truly unique facility which complements the capabilities of other world facilities in the era leading to FRIB CARIBU upgrade ATLAS Tomorrow: CARIBU & Energy Upgrade & HELIOS: Unique Synergy CARIBU HELIOS ATLAS Energy Upgrade

  24. CARIBU upgrade CARIBU • CARIBU Plan: Spring 2010: 2 mCi source  tests & yields studies Summer-Fall 2010: 100 mCi source  1st test expts. End 2010: 1 Ci source  Full research program

  25. CARIBU: Main Science Focus • Astrophysics: towards the r-process path Path critically depends on nuclear properties of neutron-rich nuclei:  mass, lifetime, b-delayed neutrons, fissionability continuation of CPT program, Greatly benefits from even the weakest source and requires > 0.1 ion/s • Nuclear Structure: Changes in shell structure and new collective modes: • Reaction dynamics • Fusion with n-rich nuclei • Deep inelastic reactions • Surrogate reactions • All marked nuclei accessible with 80 mCi source • All but about half of the grey nuclei are accessible with 2.5 mCi source • CPT moved to CARIBU • Decay studies with X-array & tape system • Shell structure with single-nucleon transfer • Pair correlations with transfer of nucleon pairs • Collective modes with Coulomb Excitation • and decay studies CARIBU enables the initial exploration of the heavy neutron-rich region using precision low-energy transfer reactions and helps develop and test the required techniques  HELIOS & other techniques (GS&FMA,..) Coulombexcitation & decay studies will address issues such as octupole collectivity in the Kr and Ba regions, triaxiality in the neutron-rich Mo and Pd regions, shape coexistence and new symmetries in Sr and Ce regions Gammasphere & FMA, GRETINA, CHICO,..

  26. HRIBF 25MV Tandem Electrostatic Accelerator Injector for Radioactive Ion Species 1 (IRIS1) Injector forStable Ion Species (ISIS) Oak Ridge Isochronous Cyclotron (ORIC) Enge Spectrograph Daresbury Recoil Separator (DRS) High Power Target Laboratory (HPTL) Recoil Mass Spectrometer (RMS) On-Line Test Facility (OLTF)

  27. HRIBF Post-accelerated Beams 175 RIB species available (+26 more unaccelerated) 32 proton-rich species 143 neutron-rich species Post-accelerated Intensity Beam list increased by ~50% since 2003

  28. Science highlights in 2009/2010 HRIBF General public highlights: http://www.phy.ornl.gov/hribf/science/abc/2009/ Experiments and outcomes http://www.phy.ornl.gov/hribf/experiments/results/ The magic nature of 132Sn explored through the single-particle states of 133Sn K. L. Jones et al., Nature, May 27 (2010) (discussed by Jones)

  29. 10 μA of 500 MeV protons on 238U (22 g/cm2) Fundamental Symmetries Radon EDM, Fr PNC 208Pb 132Sn Evolution of shell structure: towards the r process path 78Ni Halo nuclei and neutron skin Initial tests completed in Aug 2008, expect license for routine operation by fall 2010

  30. Present status of the Ariel Project • 50 MeV, 500 kW superconducting e-linac funded • requires matching funding from BC province for buildings (funded) • second proton beamline deferred until next 5YP

  31. Photo-fission of 238U (7 g/cm2) 10 mA, 50 MeV electrons on Hg converter High yields and fewer isobaric contaminants 132Sn Evolution of shell structure: towards the r process path 78Ni

  32. Rare Isotope Beam Production – Coupled Cyclotron Facility, CCF • CCF Parameters • 90 to 200 MeV/u • 1 pnA238U • 80 pnA48Ca ECR ion sources K500 A1900 K1200 • A1900 Parameters • Dp/p ~5% max • Br = 6.0 Tm max • 8 msr solid angle • 35 m in length A1900 Morrissey et al., NIM B 204, 90 (2003)

  33. Exotic Beams Produced at NSCL More than 1000 RIBs have been made – morethan 830 RIBs have been used in experiments 12 Hours for a primary beam change; 3 to 12 hours for a secondary beam

  34. Facility for Rare Isotope Beams, FRIB Broad Overview • Driver linac capable of E/A  200 MeV for all ions, Pbeam 400 kW • Early date for completion is in 2018 • In-flight 200 MeV/u, stopped, reaccelerated to 20 MeV/u LBNL

  35. Compact, more cost-effective solution Project Manager: Thomas Glasmacher Director: KonradGelbke TPC estimate $614M CD-4 Range 2018-2020

  36. Summary • We have entered the age of designer atoms – new tool for science • High power in-flight facility at FRIB and ISOL facilities at TRIUMF will allow production of a wide range of new isotopes • Necessary for the next steps in accurate modeling of atomic nuclei • Necessary for progress in astronomy (chemical history, mechanisms of stellar explosions) • Opportunities for the tests of fundamental symmetries • Important component of a future U.S. isotopes program • Other facilities play a key role in cost effective development of programs and techniques, e.g., ANC method developed at Texas A&M and resonance methods being developed at FSU • New applications range from nuclear modeling, astrophysics, fundamental interactions, and use of isotope

  37. V(r) r FRIB specialty – Produce new exotic isotopes • Large neutron skins • Modified mean field • Resonance properties 11Li 208Pb 80Ni New Science: Pairing in low-density material, new tests of nuclear models, open quantum system, interaction with continuum states - Efimov States - Reactions

  38. How do we model nuclei? • The origin of the strong force that binds nuclei is QCD. How would we prove that? Surprises are likely. • We construct potentials based on neutron and proton scattering data and properties of light nuclei (Bonn, Reid, Illinois AV18, Nijmegen, etc.) • QCD Inspired EFT (String Theory Inspired – Hashimoto et al.) Goal: Develop an Effective Field Theory based on QCD Symmetries (Furnstahl, van Kolck, Navrátil, Vary, Machliedt…) S Aoki

  39. Properties of exotic isotopes are essential in determining NN and NNN potentials • Neutron rich nuclei were key in determining the isospin dependence of 3-body forces and the development of IL-2R from UIX • New data on exotic nuclei continues to lead to refinements in the interactions • EFT developments, LQCD and even computational power are providing insight for ab initio theories, but they need grounding in data S. Pieper B.Wiringa, et al.

  40. Current status of the GFMC calculations FRIB Theory workshop talks of J. Carlson, K. Nollet

  41. Configuration space models – Example Coupled Cluster Thomas Papenbrock et al. Univ of Tennessee, FRIB Theory Workshop

  42. Solar System Elemental Abundances • Understanding the chemical history of the universe • The abundance of elements tell us about the history of events prior to stellar formation Solar system abundances Lodders (2003)

  43. Simulation of Solar System Abundances Timmes, Woosley, Weaver Astrophysical Journal 1995 • Parameters: • Supernovae type Ia and II • Number (77 supernovae with Ms 11-40 Msun) • Progenitor mass distributions • Age of the galaxy • … • Results: • SN rate1/3 comes from type Ia • Reproduction of measured 7Li abundance metalicityvs. time etc. Success ! ? Above 72 we can’t model well

  44. Mt Palomar Goal: Understanding of Astrophysical Environments n-starmergers • Use observational data to infer conditions at the site by modeling • Accurate modeling requires • that we make the same isotopes that participate in astrophysical environments • reproduce the nuclear reactions that occur in those environments • The hard part is that nature produces isotopes in environments like the r-process with T > 109 K, neutron ≈ 1020-28 cm-3 Price & Rosswog 2006 Sneden 2003; Cowan 2006 observation model CrabNebula

  45. Where do gold atoms come from? An r-process • E. M. Burbidge, G. R. Burbidge, W. A. Fowler, and F. Hoyle. (1957). "Synthesis of the Elements in Stars". Rev Mod Phy 29: 547, must be an r-procees, but … • We know they must be made in a neutron-rich environment T > 109 K, neutron ≈ 1020-28 cm-3 , that lasts for about 1 second; called the rapid-neutron capture process, r-process • Type II supernovae are a possible site (variants) • Neutrino driven shock wave • Models do not produce the entropy and neutron flux needed to match abundance data (although we can’t say that for sure) • Shock waves in C-O layers • Magnetic outflows • Colliding neutron stars would also work, but there does not seem to be enough of these in the early universe to explain how much heavier elements we see • Once the underlying physics is known, we can infer information of the site

  46. About Half of Heavier Elements must be made in an r-Process (Click on image to start animation) Nuclear physics shapes the characteristic final abundance pattern for a given r-process model

  47. Uncertainty between models and nuclear properties Astrophysics Nuclear physics 101 Hot bubble ETFSI-Q masses Classical model ETFSI-1 masses 100 Same nuclear physics Same (classical) r-process model 10-1 Abundance 10-2 10-3 Freiburghaus et al. 1999 10-4 Mass number Mass number

  48. Mass Uncertainties and r-process • Are the fine details a reflection of the site or of nuclear physics? • “Site independent model” – Fe seed nuclei are irradiated with ≈ 20 flashes of 1020 to 1028 n/cm3 over a time scale of seconds (T ≈ 1 GK) B. Sun et al. PRC 78 025806 (2008)