Nuclear Structure and Astrophysics Experiments

Transcription

1 EUROPEAN UNION GOVERNMENT OF ROMANIA Structural Instruments Sectoral Operational Programme Increase of Economic Competitiveness Investments for Your Future Extreme Light Infrastructure Nuclear Physics (ELI-NP) Project co-financed by the European Regional Development Fund Nuclear Structure and Astrophysics Experiments with ELI-NP Gamma Beams Dimiter L. Balabanski IZEST ELI-NP Conference Extreme Light s New Horizons, Embassy of Romania, Paris, September 17 th 19 th,

2 Experimental caves GBS ELI-NP experimental building Laboratories and workshops HPLS 2

3 The Gamma Beam System (GBS) ~ 4γ2 E L Laser Compton backscattering (LCB) Narrow bandwidth (0.5%) gamma-beams up to 19.5 MeV see the talk of Calin A. Ur on Friday, 9:00 3

4 Photonuclear Reactions Absorption Separation threshold ~ 8 MeV gs A X A Y Nuclear Resonance Fluorescence (NRF) Photoactivation Photodesintegration (-activation) Photofission 4

5 Nuclear Resonance Fluorescence 5

6 γ-ray spectroscopy ELIADE array 6

7 NRF Physics ELI-NP Self-absorption measurements (Γ 0 /Γ i ) Low-energy dipole response (e.g. Actinides) Dipole response and parity measurements for weakly-bound nuclei Investigation of the Pigmy Dipole Resonance Rotational 2 + states of the scissor mode Parity violation in nuclear excitation: 20 Ne Constraints on the 0νββ-decay matrix elements of the scissors mode decay channel: 150 Sm see the poster of Calin A. Ur 7

8 Physics above the neutron threshold Studies of GDR and PDR decay Studies of spin-flip M1 resonances (γ, n) cross section measurements, e.g. p process related measurements: the 138 La(γ,n) 137 La reaction, the 180m Ta(γ,n) 179 Ta reaction. Instrumentation: (i) LaBr 3 (Ce) array, (ii) Fast-neutron detector array (iii) NE213 liquid scintillator array see the poster of Dan Filipescu 8

9 Nuclear Astrophysics Molecular states and symmetries in light nuclei The 16 O(γ,α) 12 C reaction The 24 Mg(γ,α) 20 Ne reaction The 22 Ne(γ,α) 18 O reaction The 19 F(γ,p) 18 O reaction The 21 Ne(γ,α) 17 O reaction Day One experiment: Instrumentation: (i) Large-area Si DSSD array, (ii) etpc (iii) Bubble-chamber detector The 7 Li cosmological problem ELI-NP will be the ideal cite to study the 7 Li(γ, α) 3 H reaction see the poster of Ovidiu Teselianu 9

10 ELI-NP Attila Krasznahorkay (ATOMKI) Fadi Ibrahim (IPN Orsay) Dimiter L. Balabanski (ELI-NP) see the poster of Gheorghe Acbas and DLB 10

11 Physics cases 1. Studies in the 2 nd and 3 rd minimum of the fission barrier: transmission resonances 2. Rare fission modes: ternary fission 3. Structure of neutron-rich nuclei: the rare-earth neutron-rich deformed region 11

12 Resonant tunneling through the tripple humped fission barrier 12

13 232 Th(γ,f) (Dickey 1975) 232 Th(γ,f) (Knowles 1982) PLB 116B (1982)

14 (γ,f) experiment at HIγS, Csige et al., Phys. Rev. C (2013) 14

15 Ternary fission studies with ELI-NP 15

16 16

17 Instruments 1. High Efficiency Double Bragg Ionization Chamber and Si DSSD Detector Array (Double Bragg TPC) 2. Thick Gas Electron Multiplier (THGEM) DSSD - CsI Array 3. IGISOL beam line and beam transport to measurement stations IDISOL Gas Cell and RFQ Ion Cooler Laser Ion Source Mass separator Beam transport system 4. In-beam high-resolution gamma spectroscopy set-up 17

18 Double Bragg TPC This set-up will be used in two types of experiments: Studies of the properties of the fission fragments (angular, energy, mass and charge distributions) on/off the fission resonances, Identification of the ternary fission particles and study their correlation with the properties of the fission fragments defined above. 18

19 ATOMKI, Debrecen 19

20 THGEM-(DSSD-CsI) array This set-up will be used in two types of experiments: Measurement of cross-sections and fission fragment angular distributions as a function of the photon energy and mapping of fission resonances, Measurement of cross-sections and angular distributions of ternary (alpha) particles as a function of the photon energy by using polarized photons; absorbers will be used for stopping the fission fragments. Mapping of highly deformed states will be done. 20

21 γ beamγ beam ATOMKI, Debrecen 21

22 Mark Huyse 22/24 Production of pure radioactive ion beams Spallation Fusion Fission Choice of the reaction Heavy-ion fusion most selective Purification in flight (IF) or after stopping ISOL technique Fragmentation thick target <=> thin target solid catcher <=> gas catcher diffusion out of the target transfer to the ion source Z & T 1/2 dependence diffusion out of the catcher transfer to the ion source Z & T 1/2 dependence Laser Ion Ion Source Source Z dependence/selection Z to mass separator

23 The IGISOL project ISOL line Cell + RFQ Input needed : Accelerator (gammas) Infrastructure radioprotection Detection IGISOL : CARIBU-like Leuven-like 23

24 Location of the IGISOL gas catcher RFQ courtesy Neil Bliss 24

25 Principles of laser ionization 25/24 efficiency is dependent on the used transitions - cross section - available energy for that transition - temperature dependence (metastable states) - pressure dependence -... courtesy I. Moore

26 Available elements so far 26/24 85 courtesy B. Marsh

27 ALTO, ARIEL, etc. ELI-NP Laser Compton backscattering γ beam spectrum at the IP (without collimator) ~ 1011 γ/s 27

28 Photofission cross section for 238 U Caldwell et al., Phys. Rev. C 21 (1980)

29 Yield estimates Yield with a stack of targets: 10 8 f/s Al window mg/sm U targets of 19.1 mg/sm 2 29

30 Yields Donzand et al, Eur. Phys. J. A1, 407 (1998) example: with 10 8 f/s 128 Cd will be produced as ion/s 30

31 Examples for isotope yields Sn In Cd Ag ELI-NP ISOLDE CERN 31

32 Two-neutron separation energies MINIBALL (M. Albers et al.) Phys. Rev. Lett. 108, (2012) ISOLTRAP (S. Naimi et al.) JYFLTRAP (J. Hakala et al.) Phys. Rev. Lett. 105, (2010) Eur. Phys. J. A 47, 129 (2011) 32

33 Two deformed regions are known for neutron-rich nuclei, the Sr-Zr region and the rare-earth neutron-rich region. At ELI-NP it will be possible to perform β-decay and mass measurements, collinear laser spectroscopy and in-beam γ-ray spectroscopy in photofission. A program for measurements of masses, charge radii and ground-state nuclear moments of refractory isotopes exists at the IGISOL facility at JYFL in Jyvaskyla. The experiments at ELI-NP will compliment this program, starting with detailed β-decay studies as day-one experiment. Note that the rare-earth neutron-rich region has not been studied in ISOL-type experiments 33

34 γ-spectroscopic experiments coupling to ancillary detectors: fast timing with LaBr 3 det. selectivity with Bragg det. g-factors 34

35 g factors around neutron-rich N=60 using TDPAC shed light on the interplay of the proton-neutron interaction responsible for the sudden onset of deformation in the region 35

36 The Phase 2 project will be submitted to the EC in early 2015 beam dump Phase 2 γ-beam exp. area ISOL exp. area laser huts 1 st floor Research Reactor (end of decommissioning 2017) ELI NP (commissioning 2017) 36

37 Extreme Light Infrastructure Nuclear Physics 37

38 hank you! ELI-NP Team, March 5,