Magdalena Kowalska ( Contact person) Experimental investigation of decay properties of neutron deficient 116-118Ba isotopes and test of 112-115Ba beam counts Ushasi Datta Pramanik (Spokesperson) Saha Institute of Nuclear Physics, Kolkata Olof Tengblad (Co-spokesperson) Inst. de Estructura de la Materia, CSIC, Madrid, Spain Magdalena Kowalska ( Contact person) ISOLDE, CERN) 2nd Feb., 2012

many interesting structure arise Decoupling of proton and neutron many interesting structure arise PIGMY resonance / Low –lying dipole strength observed both proton and neutron-rich nuclei Clustrization Can study through decay Exotic decay mode -delayed three proton decay Two-proton radio activity  Alpha decay Decay of Intermediate Mass Fragments Schematic Diagram of nuclear potential

Physics Interest Systematic study of decay properties of nuclei near proton-drip line Mass region A~110-120 near proton drip line are enriched with a large variety of structural information Predicted as “a new island of cluster” Exotic decay modes beta delayed proton, beta delayed alpha heavier exotic clusters First , 14C clusters, H. Rose et al, Nature 307 BARDWICK, et al PRC 34, (Rap. Comm)1986 ISOLDE, 3rd November 2011

AIM: Systematic study of decay properties of 114-118Ba Study of detailed delayed proton and alpha decay What we can learn!!!!! > Resonance states, Quasi bound proton, alpha states >Coupling to continuum ISOLDE, 3rd November 2011

For Ba isotopes , what we can expect!!!!!! Systematic reduction of alpha decay width, experimentally observe (Te-Xe) Cluster structure For Ba isotopes , what we can expect!!!!!! Test of theoretical model near drip line, residual interaction, Z.Janas et al ,EPJ PN-QRPA cannot explain 117Ba decay data was not explained by pn-QRPS, residual interaction!!!!! Decay from even-even to odd-odd isotope may give important information regarding , pairing and n-p interaction near drip line I. Hamamoto, PRC 48; 1993

Test of 112-115Ba beam counts for future measurement Motivation for future measurement 112Ba (N=Z) , not known (half life, etc.)  Search for super allowed alpha decay 112Ba 108Xe 104Te 100Sn Delayed proton, alpha, exotic cluster decay mode Systematic reduction of alpha width in medium heavy nuclei Cluster structure Neutron-proton pairing

Mainly explored by Fusion Evaporation Will measure using exotic beam AZBa Delayed Proton/alpha decay b+ Decay properties in this region AZ-1Cs Mainly explored by Fusion Evaporation Will measure using exotic beam p A-1Z-2Xe Properties of proton orbital Single particle structure Nuclear shapes Nuclear life-times of the daughter (Cs) Properties of proton orbital Single particle structure Nuclear shapes Nuclear life-times of the Parent (Ba)

Exclusive decay mode in this mass region 110I , Schardt et al, NPA 368, 153, (1981) Only 117Ba, delayed proton decay studied , Z. Janas et al EPJ 2005

118Ba, 117Ba, 116Ba 115Ba Identification of b-delayed Proton, but no prior Information About b-delayed a Z. Janas et al [1] 115Ba b-delyed proton identified by Janas et al [1] half life by Guglielmetti et al [2] 114Ba Cluster decay studied by Oganessian et al[3], Guglielmetti et al[4,5] with contradiction ; a-decay studied by Mazzocchi et al [6] [1] Z. Janas; NPA 627 [2] Guglielmetti; NPA 583 [3] Oganessian; ZPA 349 [4] Guglielmetti; PRC 52 [5] Guglielmetti; PRC 56 [6] Mazzocchi; PLB 532 [7] Hecht ; AIP Conf.Proc. 819 113Ba Only 1 experimental study by Hecht et al [7], but no information about decay 112Ba No experimental study

Experiment Aim: To measure the exotic decay mode of 116-118Ba To measure life time of the nuclear level isotopes (proton unbound state) Beam development/statistics of 112-115Ba Shifts required: (real measurement) 118Ba ( t1/2 ~5.5 sec) ----- (105/sec) 6 shifts (p~ 4x10-4/sec, ~ 4x10-5/sec 117Ba ( t1/2 ~1.75 sec) ----(104/sec ) 6 shifts (p~ 0.13/sec, ~ 4x10-4/sec 116Ba ( t1/2 ~1.35 sec) -------(104/sec ) 6 shifts ((p~ 0.03/sec, ~ 4x10-4/sec 112-115Ba ( t1/2 < 1 sec) ---(beam count 4 shifts for future studies) Total …….22 shifts. ISOLDE, 3rd November 2011 ISOLDE, 3rd November 2011

Experimental Set-up:: Measurement delayed proton, alpha, X or g-ray in coincident with delayed p or alpha Measurement of nuclear level lifetime of the order of sub pico-seconds or femto- seconds (10-16-10-18 sec

Collaborators J. Ray1, P. Bhattacharya1, A. Becerril2, Y. Blumenfeld3, M. J.G. Borge2, S.Chakraborty1, S. Chatterjee1, L.M.Fraile3, H.O.U. Fynbo4, A. Heinz5, B. Jonson5, K.Kar1, U. Köster6, M. Kowalska3, S.Mandal7, B.Mukherjee8, E. Nacher2, T. Nilsson5, G. Nyman5, K. Riisager4, A. Rahaman1, P. Reiter9, T. Stora3, P.J.Wood 10 1Saha Institute Of Nuclear Physics, Kolkata, India 2Inst. de Estructura de la Materia, CSIC, Madrid, Spain 3ISOLDE, CERN, France 4Dept. of Physics and Astronomy, Aarhus Univ., DK-8000 Aarhus C, Denmark 5Fundamental Fysik, Chalmers Tekniska Hogskola, S-41296 Goteborg, Sweden 6IIL, Grenoble, France, 7University of Delhi, India, 8University of Viswa Bharati,India 9Institut fuer Kernphysik, Universitaet zu Koeln, D-50937, Koeln 10, University of Edinburgh, EH93JZ, UK ISOLDE, 2nd , Feb, 2012

ISOLDE, 3rd November 2011

ISOLDE, 3rd November 2011

ISOLDE, 3rd November 2011

112Ba 108Xe 112Cs 104Te 111Xe 108I 100Sn b+ a a p a a 0.5 ms 0.81s Qb+ = 9200 keV Qa = 4200 keV ba = ? b+ a 0.5 ms 108Xe Qa = ? ba = ? 112Cs Qp = 814 KeV bp = 100% a Qa = 3930 KeV ba = p 0.81s 104Te Qa = ? ba = ? 111Xe a a 36 ms 108I 100Sn

114Ba 110Xe 114Cs 106Te 113Xe 110I 102Sn b+ a a p a a 0.43s 93 ms Qb+ = 7700 keV Qa = 1480 keV ba = 0.9% b+ a 93 ms 0.57s 110Xe Qa = 3870 KeV ba = 64% 114Cs Qp = bp = a Qa = 3360 KeV ba < 0.1% p 70 ms 106Te Qa = 1660 Kev ba = 100% 2.74s 113Xe a a 0.65s 0.43s 110I 102Sn

114-118Ba isotopes – special interest Very close to the proton drip line and in the mass region we are interested in (A~110-120) ISOLDE, 3rd November 2011

114-118Ba isotopes – special interest more than 20 theoretical predictions on cluster decay, Experiments in contradiction with each other Phys.Rev. C51, 594 (1995) D. N. Poenaru predicted emission of 12C from 114Ba Guglielmetti (1995), NPA583 12C from 114Ba 114-118Ba decay Z.Janas NPA 627 (1997)119 PRC56, R2912 (1997) Guglielmetti shows non-observation of 12C from 114Ba ISOLDE, 3rd November 2011 ISOLDE, 3rd November 2011

Collaborators J. Ray1, P. Bhattacharya1, A. Becerril2, Y. Blumenfeld3, M. J.G. Borge2, S.Chakraborty1, S. Chatterjee1, L.M.Fraile3, H.O.U. Fynbo4, A. Heinz5, B. Jonson5, K.Kar1, U. Köster6, M. Kowalska3, S.Mandal7, B.Mukherjee8, E. Nacher2, T. Nilsson5, G. Nyman5, K. Riisager4, A. Rahaman1, P. Reiter9, T. Stora3, O. Tengblad2 1Saha Institute Of Nuclear Physics, Kolkata, India 2Inst. de Estructura de la Materia, CSIC, Madrid, Spain 3ISOLDE, CERN, France 4Dept. of Physics and Astronomy, Aarhus Univ., DK-8000 Aarhus C, Denmark 5Fundamental Fysik, Chalmers Tekniska Hogskola, S-41296 Goteborg, Sweden 6IIL, Grenoble, France, 7University of Delhi, India, 8University of Viswa Bharati,India 9Institut fuer Kernphysik, Universitaet zu Koeln, D-50937, Koeln ISOLDE, 2nd , Feb, 2012