From nucleons, to nuclei, to fusion reactions

Transcription

1 From nucleons, to nuclei, to fusion reactions CUWiP 14 Berkeley, January 19, 2014 Sofia Quaglioni Collaborator: P. Navrátil (TRIUMF) LLNL-PRES This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under contract DE-AC52-07NA Lawrence Livermore National Security, LLC

2 Outline The job of a theoretical nuclear physicist Can we accurately describe how nuclei are put together from the neutron and proton constituents? Can we predict the phenomena of nuclear reactions based on colliding nuclei made of interacting nucleons? Betelgeuse About myself Formation, career, life Questions? α Alpha particle Lawrence Livermore National Laboratory LLNL- PRES

3 One of the central goals of nuclear physics is to come to a basic understanding of the structure and dynamics of nuclei What are the nuclear reactions that drive stars? What is the origin of the elements? Can we understand exotic nuclei? What is the nature of the nuclear force? Can we accurately predict reactions in Earth-based fusion facilities? Lawrence Livermore National Laboratory LLNL- PRES

4 From nucleons to nuclei and their reactions Based on the laws of Quantum Mechanics, can we describe nuclei and reactions between nuclei in terms of interacting nuclei? Two major obstacles: proton neutron quark 1. Interactions among nucleons are not known precisely - Need to test different models A nucleons 2. Many-body problem extremely hard to solve: - << many Hottentot tribes do not have in their vocabulary the names for numbers larger than three. Ask a native down there how many sons he has or how many enemies he has slain, and if the number is more than three he will answer many >> From: One two three infinity by G. Gamow Lawrence Livermore National Laboratory LLNL- PRES

5 The nuclear many-body problem Solve the equations of Quantum Mechanics A (all active) nucleons 9 A degrees of freedom (position, spin, isospin) Nucleons cannot occupy the same quantum state (Pauli principle) Nucleons can interact in pairs, but also in triplets Exact/analytical calculations impractical! Need High Performance Computers My job: develop smart theoretical approaches and efficient parallel computer codes to solve this problem If my theory is right it will reproduce known measured quantities and can be used to make predictions Lawrence Livermore National Laboratory LLNL- PRES

6 I will show cross sections, usually indicated by σ A classical view: Detector: e.g., Velcro Projectile/probe: e.g., tennis balls Target: e.g., steel disk σ Microscopically things are much more fuzzy The effective area depends on - Type of interaction, energy, etc. Lawrence Livermore National Laboratory LLNL- PRES

7 Scattering and cross section (effective area) P = N T σ 1 cm 2 = N s N I Rutherford scattering is the most famous example (1909) dσ dω = 1 4 $ Ze 2 ' & ) % E ( 2 1 sin 4 (ϑ /2) H. Geiger E. Marsden E. Rutherford Lawrence Livermore National Laboratory LLNL- PRES

8 The 3 H(d,n) 4 He and 3 He(d,p) 4 He fusion P. Navrátil, S. Quaglioni, Phys. Rev. Lett. 108, (2012) d 3 H n 4 He Nuclear astrophysics: Predictions of Big Bang nucleosystesis for light-nucleus abundances Fusion research and Plasma physics: d+t is the easiest fusion to achieve on Earth; 3 H(d,γ) 5 He branch useful for diagnostic, not known well enough Atomic physics: Considerable electron-screening effects in d+ 3 He not completely understood 4 He D 3 He 7 Li S-factor [MeV b] Astrophysical S-factors! 3 H(d,n) 4 He astrophysical E kin [MeV] S-factor! S-factor [MeV b] H(d,n) 4 He (b) My theory d+ 3 He p+ 4 He BR51 AR52 CO52 AR54 He55 GA56 BA57 GO61 KO66 MC73 MA75 JA84 BR87 9d*+ 5d'* Bo52 Kr87 Sch89 Ge99 Al01 Al01 Co05 0d*+0d'* 1d*+1d'* 3d*+3d'* 5d*+5d'* 7d*+5d'* 9d*+5d'* E kin [kev] Lawrence Livermore National Laboratory LLNL- PRES

9 Accurate evaluations and uncertainties for fusion diagnostic The elastic n- 3 H cross section for 14 MeV neutrons, important for understanding how the fuel is assembled in an implosion at NIF, was not known precisely enough 3 H(n,n) 3 H cross section! corrected 3 H n (14 MeV) 3 H n 3 H My theory d 4 He Nuclear theory was asked to help Calculation corrected at forward angles to account for target breakup (~ 15% effect) Delivered evaluated data with required 5% uncertainty Ab initio theory reduces uncertainty due to conflicting data (,w,,, ) Lawrence Livermore National Laboratory LLNL- PRES

10 Working hard or having fun? The physics of atomic nuclei is fundamental to the very existence of the universe. Being a nuclear theorist and helping to complete the puzzle can be a lot of fun! And now about myself Lawrence Livermore National Laboratory LLNL- PRES

11 About myself 1. Born in Italy (1978) 2. Liceo Classico studies ( ) 3. Laurea (B.S.+M.S.) in physics ( ) Who changed my mind? Lawrence Livermore National Laboratory LLNL- PRES

12 Prof. Giuseppina Orlandini, my inspiration and mentor Lawrence Livermore National Laboratory LLNL- PRES

13 About myself 4. Ph.D. in Theoretical Nuclear Physics ( ) Lawrence Livermore National Laboratory LLNL- PRES

14 all the while studying to become an opera singer Lawrence Livermore National Laboratory LLNL- PRES

15 About myself 5. Postdoc at the University of Arizona ( ) Lawrence Livermore National Laboratory LLNL- PRES

16 I met my future husband physicist too Lawrence Livermore National Laboratory LLNL- PRES

17 About myself 6. Postdoc at LLNL ( ) Lawrence Livermore National Laboratory LLNL- PRES

18 A lot happened in Outstanding Postdoc Fellow Lawrence Livermore National Laboratory LLNL- PRES

19 About myself 7. LLNL Member of Scientific Staff ( present) Lawrence Livermore National Laboratory LLNL- PRES

20 2010 and 2013: two very productive years 2010, Leon Yves 2013, Filippo Pietro Lawrence Livermore National Laboratory LLNL- PRES

21 2011 DOE s Early Career Award Lawrence Livermore National Laboratory LLNL- PRES

22 Summarizing I succeeded to get a higher education in physics I was able to combine my passion for physics and music I did not give up my aspirations of being a wife and a mom My children did not slow down but gave a boost to my career I have a very full life, but I love it. If you really want it, nothing can stop you! Questions? Lawrence Livermore National Laboratory LLNL- PRES