Study of compression modes in 56 Ni with the active target MAYA - PowerPoint PPT Presentation

Study of compression modes in 56 Ni with the active target MAYA Soumya Bagchi KVI-CART, University of Groningen NUSTAR Annual Meeting 2014

Outline • Introduction to Giant Resonances • Importance of compression modes in nuclei • Experimental Setup • Results • Summary and outlook 6th March, 2014 NUSTAR Annual Meeting, GSI | Soumya Bagchi 2

Giant Resonances (GR) Isoscalar Isovector Compression In phase Out of phase modes Monopole L = 0 (GMR) Dipole L = 1 (GDR) 6th March, 2014 NUSTAR Annual Meeting, GSI | Soumya Bagchi 3

Giant Resonances (GR) Isoscalar Compression In phase modes Monopole L = 0 (GMR) Dipole L = 1 (GDR) [T. Li., et al., PRC 81 , 034309 (2010)] 6th March, 2014 NUSTAR Annual Meeting, GSI | Soumya Bagchi 4

Giant Resonances (GR) Isoscalar Isovector Photo absorption cross sections Compression In phase Out of phase modes Berman and Fultz, Rev. Mod. Phys. 47 (1975) 47 65 Cu Monopole L = 0 (GMR) 120 Sn Dipole L = 1 (GDR) 208 Pb Macroscopically: • Excitation Energy • Width 6th March, 2014 NUSTAR Annual Meeting, GSI | Soumya Bagchi 5

Nuclear Incompressibility Incompressibility : Measure of the resistance of matter to uniform compression 6th March, 2014 NUSTAR Annual Meeting, GSI | Soumya Bagchi 6

Why study nuclear incompressibility?  Key input to the EoS of the nuclear matter EoS of the nuclear matter is important for studying: • Core collapse and supernovae explosion • Formation of neutron star • Collisions of heavy ions 6th March, 2014 NUSTAR Annual Meeting, GSI | Soumya Bagchi 7

Why Ni? Incompressibility value ( K ∞ ) obtained from isotopic • chain of Pb: 240 ± 10 MeV [G. Colò et al ., PRC 70 , 024307 (2004)] Sn and Cd: 210 – 215 MeV [T. Li., et al., PRC 81 , 034309 (2010)] [D. Patel., et al., Phys. Lett. B 718 (2012) 447 – 450] Why is there a discrepancy in K ∞ values between Sn/Cd • and Pb?  Need to study for a series of isotopes of a nucleus 6th March, 2014 NUSTAR Annual Meeting, GSI | Soumya Bagchi 8

53 Ni 57 Ni 58 Ni 54 Ni 55 Ni 56 Ni n 56 Ni 45 ms 35.6 h stable 104 ms 205 ms 6.08 d p 52 Co 53 Co 54 Co 55 Co 56 Co 58 Ni 115 ms 242 ms 193 ms 17.53 h 77 d 60 Ni α 68 Ni 51 Fe 52 Fe 53 Fe 54 Fe 305 ms 8.28 h 8.51 m stable 6th March, 2014 NUSTAR Annual Meeting, GSI | Soumya Bagchi 9

Primary Target: 9 Be Secondary Beam: Primary Beam: 56 Ni at 50 MeV/u (thickness 500 μ m) 58 Ni at 75 MeV/u GANIL Facility 9 Be 56 Ni 58 Ni 54 Co 55 Co Primary target 9 Be 53 Fe 95-97% 56 Ni ~ 10 4 pps MAYA setup 56 Ni ( α , α ’) 56 Ni* 6th March, 2014 NUSTAR Annual Meeting, GSI | Soumya Bagchi 10

Challenges with exotic beams: • Intensity of exotic beams is very low (~10 4 – 10 5 pps) • To get reasonable yields thick target is needed • Very low energy (~ sub MeV) recoil particle will not come out of the thick target Active target : Detection takes place at every point of the target ( Detector and target are the same ) Good angular coverage • Effective target thickness can be increased • without much loss of resolution Detection of very low energy recoil particle is possible • 6th March, 2014 NUSTAR Annual Meeting, GSI | Soumya Bagchi 11

Angular distribution: DWBA 56 Ni ( α , α ’) 56 Ni* 6th March, 2014 NUSTAR Annual Meeting, GSI | Soumya Bagchi 12

ISGDR Elastic ISGMR 6th March, 2014 NUSTAR Annual Meeting, GSI | Soumya Bagchi 13

MAYA setup Cathode _ 3000 V 56 Ni 22 cm E drift 500 mbar Anode Wire 95% He and 5% CF 4 +1300 V 6th March, 2014 NUSTAR Annual Meeting, GSI | Soumya Bagchi 14

MAYA setup 6th March, 2014 NUSTAR Annual Meeting, GSI | Soumya Bagchi 15

Si/CsI Telescope in MAYA Recoil He Recoil He Beam 56 Ni Beam 56 Ni 20 Si 80 CsI 6th March, 2014 NUSTAR Annual Meeting, GSI | Soumya Bagchi 16

Mask Beam entrance Δ E-E detector Cathode pad 6th March, 2014 NUSTAR Annual Meeting, GSI | Soumya Bagchi 17

Particle Identification in forward Δ E-E telescope 6th March, 2014 NUSTAR Annual Meeting, GSI | Soumya Bagchi 18

Kinematics reconstruction Bragg Peak Vertex Beam 56 Ni Recoil He Two dimensional range 6th March, 2014 NUSTAR Annual Meeting, GSI | Soumya Bagchi 19

Kinematics reconstruction Bragg Peak Two dimensional range Beam Wires Cathode plane 6th March, 2014 NUSTAR Annual Meeting, GSI | Soumya Bagchi 20

Kinematics reconstruction Bragg Peak Anode wires Two dimensional range Third Wires Beam dimension Cathode plane e -  Track is going in the upward t n > t 0 direction Range Energy t n t 0 6th March, 2014 NUSTAR Annual Meeting, GSI | Soumya Bagchi 21

Angular Distribution 6th March, 2014 NUSTAR Annual Meeting, GSI | Soumya Bagchi 22

Excitation energy of 56 Ni Elastic ISGMR ISGDR 6th March, 2014 NUSTAR Annual Meeting, GSI | Soumya Bagchi 23

Summary • Compression modes in 56 Ni are studied. • Active target has been used to study the compression modes. • Preliminary results are shown. Outlook • Excitation energies of the compression modes will be determined. • Angular distributions of ISGMR and ISGDR will be studied. • Nuclear incompressibility will be measured from the excitation energies. 6th March, 2014 NUSTAR Annual Meeting, GSI | Soumya Bagchi 24

6th March, 2014 NUSTAR Annual Meeting, GSI | Soumya Bagchi 25