Nuclear structure ALTO present and near-future perspectives. G. Georgiev

Transcription

1 Nuclear structure ALTO present and near-future perspectives G. Georgiev

2 Experimental areas g-spectroscopy Bacchus Split-Pole spectrometer ISOL production cave e LINAC ISOL experimental cave (~100 m 2 ) Radioactive beam lines cluster, molecular & droplets beams Stable beam w/o spectrometer Stable beam with spectrometer

3 The ALTO PAC Richard Casten Yale, USA, Chair Dimiter Balabanski ELI-NP, Romania Emmanuel Balanzat CIMAP/GANIL, France Marcella Grasso IPN Orsay, France Stéphane Grévy Bordeaux-Gradignan, France Adam Maj IFJ PAN Kraków, Poland Paddy Regan Univ. Surrey, UK Peter Reiter Univ. Koeln, Germany Berta Rubio CSIC-Univ. Valencia, Spain Jean-Charles Thomas GANIL, France Christina Trautmann GSI, Darmstadt, Germany Aurora Tumino Kore Univ. Enna & LNS-INFN Catania, Italy Call for proposals once a year

4 Beam-time and users ( ) (present) Users ~120 ~ ~150 Beam-time 1752 h 3600 h 2712 h 2232 h 3816 h 2112 h 219 UT 450 UT 339 UT 279 UT 477 UT 264 UT ALTO - TNA within ENSAR and ENSAR2

5 2015 run 2015 record beam time, limited by the number of operators available High percentage of stable and radioactive nuclear physics experiments Split Pole 2 campaigns RIB 2 campaigns True parallel operation of stable and radioactive beams over several weeks 34 days of RIB in two campaigns

6 Stable-beam Studies at ALTO

7 Nuclear astrophysics studies with Split-Pole Particle decay branching ratios for states of astrophysical importance in 19 Ne States in 19 Ne above 15 O+a and 18 F+p thresholds play an important role in explosive H-burning. Energetics in X-ray bursts [ 15 O(a,g) 19 Ne] & g-ray emission in classical novae [ 18 F(p,a) 15 O]. Reaction rate has a linear dependence to branching ratios (BR). coincidence measurement of 19 F( 3 He,t) 19 Ne*(a p) with Split-Pole and a DSSSD array E( 3 He) = 25 MeV I( 3 He) ~ 70 ena CaF 2 ~ 200 mg/cm 2 Q SP = 10 beam Target Split-Pole DE/E ~ 10-4 t t t t-a angular correlation Yale 2003 Orsay 2015 E X = 6742 kev Smaller binning (higher statistics) Better c.m. angular coverage toward 90 Target Beam better BR determination Shield J. Riley, A. M. Laird, N. de Séréville, A. Parikh et al. 6 W1 (16+16) DSSSDs angular distribution measurement e ~ 15%, DE ~ 20 kev Thick shield between 0 FC and DSSSDs

8 Gamma-ray spectroscopy with ORGAM TDRIV on H-like ions in RIB geometry: 24 Mg beam: 24 MeV (5 MeV/u) target: 2.4 mg/cm 2 93 Nb reset Foil: 1.7 mg/cm Au Previous measurement: g(2 + ) = 0.51 (2) R.F. Horstman et al., NPA 248, 291 (1975) Our result: g(2 + ) = (13) A. Kusoglu et al. PRL 114, (2015) 24 Mg 2 + state USD shell model: g(2 + )=0.544

9 MINORCA at ALTO (June 2014 March 2015) Campaign managers: I. Matea and G.G. 12 ORGAM CS HPGe x 0.1% 8 Miniball TC at ~14 cm from target 7.3% 1.33 MeV ancillary detectors: - Orsay plunger (OUPS) - particle detector - DSSD

10 MINORCA physics cases Campaign managers: I. Matea and G.G.

11 Lithium Inverse Cinematics ORsay NEutron source Sample H target 100nA 7 Li MeV γ γ n-induced fission of 238 U n n n n TIPS tagging of 10 7 n/s/cm 2 isomer partners LICORNE Exoticity EXILL SF J. Wilson, M. Lebois et al. Testing ground for NFS@SPIRAL2

12 ν-ball: a hybrid LaBr 3 -Ge array for g-ray spectroscopy studies Hybrid Ge + LaBr 3 array + ALTO 24 g-pool Clover detectors + 36 LaBr 3 (FATIMA)or phase 1 Ge s Ge efficiency ~ 7 % total; LaBr3 efficiency ~5 % Combination with ancillary devices (OUPS, part. det., neutron source ) Call for proposals very soon; ALTO PAC Feb./March 2018

13 nu-ball a few physics cases nu-ball hybrid spectrometer workshop May, 2016, Orsay

14 Radioactive Ion Beams at ALTO

15 Inauguration of ALTO green light from French nuclear safety authorities officially granted Spring 2012

16 Progress in the RIB instrumentation (so far) 3 modes, 3 commissioning's, 3 physics results BEDO setup in gamma mode 4 small EXOGAM clovers BEDO setup in neutron mode Dubna neutron detector TETRA BEDO setup fast timing mode LaBr3 IPN, coll. CSNSM, IPHC IPN, coll. JINR (Russia), IPHC IPN, coll. CSNSM, TANDAR (Argentina), INRNE (Bulgaria) PhD: A. Etilé (CSNSM) PRC 91, (2015) PhD: D. Testov (IPN) NIM A815, 96 (2016) M.A.Cardona, D.Hojman, B.Roussière, I.Deloncle et al. to be submitted

17 First evidence of shape coexistence in the 78 Ni region Analysis performed by Andrea Gottardo (IPN Orsay) d 3/2 s 1/2 Compatible with the T 1/2 for the 3 isomer in 80 Ga [T 1/2 (3 )=1.3 0,2 s; Verney et al. PRC 87 (2013)] A situation very similar : populated in the 3 72 Ga decay [Rester et al NPA 162 (1971)] 50 d 5/2 g 9/2 Gottardo, Verney et al. PRL 116, (2016)

18 Present RIB setups and near-future projects Parrne mass separator 3 projects (partially) financed through a «laboratory of excellence» program: LINO POLAREX MLL-trap Identification station TETRA (existing) TAS (existing) MLL Trap (project) Mass measurements ++ POLAREX (project) LTNO ( 3 He/ 4 He) LINO (project) BEDO (existing) Laser-Induced nuclear orientation (µ,q, J p )

19 Charting Terra Incognita Project leader ALTO related sub-projects POLAREX MLL - trap LINO S3 related part

20 Installation of - September 2016 Modification of the platform (space for MLLtrap) Vacuum, cryogenic and electrical connection ongoing PolarEX structure Transport of the cryostat Transport of the cryostat ALTO (side view) ALTO (top view)

21 LINO present status γ detection n detection β detection fluorescence detection β-delayed spectroscopy of polarized beams post acceleration & neutralization laser and ion beam coupling

22 Continuous Beam from 30 / 60 KeV MLLTRAP : High-precision mass measurements at ALTO TOF-ICR PI-ICR March 2016 PT-MS The truck left Garching (MLL) towards Orsay (Alto) the 14 th of July 2016 RFQ Cooler and buncher Buffer gas < 3 kev MCP MCP 60 kv RFQ Design COLETTE 2r 0 = 14 mm, 15 segments High-precision mass measurements Measurement Trap Pumping barrier Purification Trap Detector Trap δm/m 10-6 Nuclear fine structure Astrophysics Weak interaction studies Atomic physics Trap-assisted spectroscopy : Design & construction RFQ, installation MLLTRAP 2018 : Off-line commissioning RFQ and MLLTRAP 2019 : On-line experiments In-trap decay spectroscopy Enrique Minaya Ramirez, Serge Franchoo, Marion MacCormick Araceli Lopez-Martens, Karl Hauschild, Joa Ljungvall, David Lunney

23 Summary ALTO is a small-scale facility providing both stable and radioactive beams. The obtained physics results can have a considerable impact. Nuclear structure studies through g-ray spectroscopy and nuclear reactions are a few of the important contributions of ALTO ISOL started initially as a test-bench for SPIRAL2 the RIB studies (beyond standard b-decay ) are already providing results with high scientific importance

24 Outlook ALTO and GANIL (Cyclotrons + SPIRAL1 + SPIRAL2) are the two French facilities for exploring nuclear structure and reactions Coordination and common scientific policy is our common goal

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