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F. Scarlassara

The PRISMA spectrometer. Features and experiments. PRISMA. CLARA. Main Physics goal Multi-nucleon transfer reactions, from quasi-elastic to deep inelastic (correlations) Nuclear structure of the n-rich nuclei produced, with the Clover g -array Possible experiments with radioactive beams.

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F. Scarlassara

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  1. The PRISMA spectrometer. Features and experiments PRISMA CLARA Main Physics goal Multi-nucleon transfer reactions, from quasi-elastic to deep inelastic (correlations) Nuclear structure of the n-rich nuclei produced, with the Clover g-array Possible experiments with radioactive beams F. Scarlassara for the PRISMA+CLARA collaboration F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  2. n pick-up 235 MeV 40Ca + 208Pb 40Ca p stripping A Multi-nucleon transfer nuclide production measured with ToF spectrometer PISOLO (4msr) Z the situation with PRISMA (80msr) Production of n-rich nuclei Populated at high spin, yrast states Residual nuclear interaction Evolution of the single-particle levels F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  3. EFB EFB 3230 mm 800 mm Magnetic Quadrupole. diameter 30cm effective length 50cm Magnetic Dipole. deflection angle 60° Maximum rigidity 1.2Tm pole gap: 20cm Hybrid traditional Spect-HEP tracking Detectors and Magnetic elements are complementary Deisgn features of Prisma Solid angle ~ 80 msr Mom. acceptance ± 10% Maximum rigidity 1.2 Tm Dispersion 4 cm/% Energy resolution 1/1000 Mass resolution 1/300 FWHM Only possible through trajectory reconstruction F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  4. EFB MCP EFB 3230 mm C-foil ions 800 mm MCP start detector X,Y resol. < 1 mm negligible straggling Xin, Yin, Tin Anode readout based on 2 orthogonal delay lines. Home-made delay lines of 70 µm Cu-Be DT ~ 350 ps G.Montagnoli et al. Nuc.Instr.Meth. A547(2005)455 F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  5. EFB EFB 3230 mm 800 mm S.Beghini et al. Nucl.Instr.Met. A551 (2005)187 Xin, Yin, Tin Multi-wire PPAC. 100x13 cm 10 sections, 10x13 cm 1mm X res. 2mm Y res. Gas : C4H10 @ 7 hPa Xout, Yout, Tout F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  6. EFB EFB 3230 mm 800 mm S.Beghini et al. Nucl.Instr.Met. A551 (2005)187 Xin, Yin, Tin Xout, Yout, Tout E, DE, Range .. CH4 or CF4 @ < 100 hPa Ionization Chamber. entrance window 100x13cm 10x4 sections 10x25cm2 each F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  7. EFB EFB 3230 mm 800 mm Xin, Yin, Tin CLARA array ToF Xout, Yout, Tout • 24 - 25 Clover detectors • from Euroball • ~3 % efficiency • peak/total ~ 45 % • FWHM ~ 10 keV at v/c=10 % E, DE, Range .. Doppler correction by entrance position and reconstructed velocity F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  8. A B C fission events Z=50 D proton pick-up channels E (A+B) Z=34 proton stripping channels E (A+B+C+D) IC Energy IC Range Particle identification. Z from the IC IC the granularity of the IC allows some flexibility, in particular it allows to optimize the resolution F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  9. 20° TARGET L2=ar 5° MCP QUADRUPOLE DIPOLE L3 a r MWPPAC IONIZATION CHAMBER Determination of A through Trajectory Reconstruction Xin, Yin From Xin,Yin,Xout the trajectory is determined by iteration a magnetic rigidity + the pathlength Xout, Yout adding ToF information yields the velocity and after calibrating the different ToF spectra F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  10. Coarse and fine matching of TOF offsets TOF [10-10 sec] D/R [arb. units] 2762 TOF 1382 0 1023 focal-plane X [mm] ToF etc. (final alignment of mass peaks) F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  11. 20° TARGET L2=ar 5° MCP QUADRUPOLE DIPOLE L3 a r MWPPAC IC Energy IONIZATION CHAMBER combine results to get q .... Determination of A through Trajectory Reconstruction Xin, Yin Xout, Yout DA/A ~ 1/200 0.5% Energy resolution ... and finally A F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  12. Focal plane 60° 120 cm Dipole 50 cm Quadrupole 30 cm Beam Start detector Target Rotating platform PRISMA Spectrometer F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  13. N=Z 1st experimental campaign Multi-nucleon transfer 90Zr+208Pb 40Ca + 208Pb Pairing-vibrational states in 42Ca 82Se+238U 32S+58Ni Mirror pair 31S and 31P Shell closure evolution at the magic number N=50 64Ni+238U 54Fe+50Cr Shell model A~60 Isospin non conserving part of the effective interaction in 54Co 36S + 208Pb 24Mg + 24Mg Shell model in 37P and 39P Breaking of semi-magic shell closure far from stability Resonances in 24Mg+24Mg molecular states in 48Cr F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  14. 404MeV 64Ni+238U PR=64° g9/2 region Onset of deformation towards N=40 2+→0+ -2p4n 4+→2+ 2+→0+ -2p2n 4+→2+ 2+→0+ -2p 4+→2+ 2+→0+ -2p+2n 4+→2+ • First identification of 4+ and possibly 6+ states in 64Fe • The experimental R(4/2) ratio indicates a structure change for N≥38 • Shell-model calculations predicts that the g9/2 orbit has strong influence on the structure of even-even Fe isotopes with N≥38 • The onset of deformation seems confirmed by the experimental data F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  15. 404MeV 64Ni+238U g=64° Spectroscopy of heavy Cr isotopes First observation of g rays from the yrast levels of 58Cr -4p-6n -4p-2n -4p F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  16. 404MeV 64Ni+238U g=64° axially deformed g-soft rotor 58Cr spherical vibrator -softness in heavy Cr and Fe isotopes 58Cr has exactly the structure predicted for E(5) critical point N. Marginean et al. Phys. Lett. B 633(2006)696 • The R(4/2) ratio in Fe isotopes is very close to the value of 2.50 specific to -soft rotors • The R(4/2) ratio in Cr isotopes is increasing towards the same value F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  17. 505MeV 82Se+238U PR=64° Z/N equilibration Evolution of the N=50 shell: Searching for shell gap quenching (onset of deformation as in N=20 Z~12) Nuclear spectroscopy of A~ 80 n-rich nuclei Multi-nucleon transfer Deep–inelastic collisions a powerful tool to populate moderately neutron-rich nuclei F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  18. 505MeV 82Se+238U PR=64° fission events Fission Z=50 proton pick-up channels E (A+B) Z=34 proton stripping channels E (A+B+C+D) v/c range : 4-10% Mass range : 50-110 -10p -14n PRISMA: efficiency and resolving power up to 24 nucleons removed from the projectile ! F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  19. 505MeV 82Se+238U PR=64° 279 Transitions identified for first time with CLARA-PRISMA 227 -2n -4n -3n -1n -1p +1n +2n 139 524 121 466 352 1040 1086 1133 Level scheme from a thick target GASP exp. 460 MeV 82Se+192Os Spectroscopy of the As isotopes 80As (-1p -1n) • First observation of  rays from the decay of 80As • theisomeric237 keVtransitionismissingintheCLARA-PRISMAspectrum F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  20. 505MeV 82Se+238U PR=64° +2n -1p -2p +2n -3p +2n Spectroscopy of the lightest N=50 isotones • First observation of  rays from the decay of 81Ga • The excitation energy of the 4+ state in 82Ge firmly established • First observation of the yrast levels of 83As F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  21. 505MeV 82Se+238U PR=64° +3n +2p +3n 51 Spectroscopy of odd-A N=51 isotones First identification of yrast states in 85Se and 87Kr F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  22. 505MeV 82Se+238U PR=64° Rotor Middle of Z=28-40 shell +4n Vibrator N=52 even-even nuclei 51 Evolution of collectivity in light N=52 nuclei • 1st observation of the 4+ → 2+ transition in 86Se • The R(4/2) ratio in N=52 even-even nuclei • indicates an increase of collectivity at lower Z F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  23. Positive superconductive injector PIAVE 22Ne - 40Ar available to users from the 2nd semester 2006 136Xe and few metallic beams available soon Positive ion injector ECRIS + PIAVE commissioned F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  24. 70o --DANTE coincidences DANTE setup A ring of MCP detectors mounted around the grazing angle ~20% 4 ~30 times higher than PRISMA High efficiency tagging detector Doppler correction of the  spectra Geometries depend on the angle with respect to PRISMA F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  25. 10 m diameter Au plated Tungsten wires 1.5 m Mylar cathode + 20 g/cm2 Al Delay line read-out New FPDs for light-ions 15 cm 100 cm F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  26. Secondary Electron Detector a new FPD for low energy heavy-ions (E<10 MeVA; Z>10) 420 a 80 mg/cm2 Emissive foil (Vf = 10 kV) Mylar 0.6 m + Al 30 nm Extraction Acceleration E Accelerating grid (Vg = 0V) Guiding Focusing B Thin window (0.9 m) 0 V Y strips (Wires) Detection LPMWPC HV + X strips 0 V Dt ~ 150 ps DX, DY ~ 2 mm C4H10 – 5hPa F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  27. 1 symmetric triple-cluster 4 asymmetric triple-clusters 15 36-fold segmented crystals 540 segments 555 digital-channels Eff. 3 – 8 % @ M = 1 Eff. 2 – 4 % @ M = 30 Main issue is Doppler correction capability  coupling to beam and recoil tracking devices The ASC has approved a commissioning campaign at the LNL, followed by an experimental campaign. The array will be placed at the PRISMA site, to replace the CLARA array. Operation to start in 2008. The AGATA Demonstrator Objective of the final R&D phase 2003-2008 F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  28. EFB EFB The setup for the GFM operation of Prisma 1.2Tm Prisma at 0° 1.5Tm detector shifted 30cm C-foil window 50mg/cm2 beam dump DRIFT Detector chamber F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  29. 197Au 58Ni Trajig calculation for @60° 0° aperture 0.01mb 0.1mb 0.5mb 1 mb 2 mb 3 mb 5 mb F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  30. Summary • The PRISMA+CLARA setup, consisting of the magnetic spectrometer PRISMA coupled to an array of 25 EUROBALL Clover detectors, has started its 4th year of operation at LNL. • In a single, few-days experiment ~ 50 nuclei can be studied, and resullts show that experiments with stable beams and instruments like PRISMA+CLARA can contribute to the study of moderately n-rich nuclei. • A new array (DANTE) of position sensitive detectors has been commissioned to allow g-g-DANTE coincidences to build the level scheme once the transitions are assigned. • New instrumentation development foreseen for in-beam commissioning at LNL in the next months, mostly within the JRAs of EURONS. F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  31. INFN and University of Padova G. Montagnoli, S. Beghini, F. Scarlassara, P. Mason, E. Farnea, C.A. Ur, S.M. Lenzi, S. Lunardi, D. Bazzacco, R. Menegazzo INFN Legnaro A.M. Stefanini, L. Corradi, E. Fioretto, B. Guiot, A. Gadea, N. Marginean, J.J. Valiente-Dobón, F. Della Vedova, R. Orlandi, G. de Angelis, D.R. Napoli, L. Berti, N. Toniolo Ruder Boskovic Institute, Zagreb, Croatia S. Szilner INFN and University of Napoli M. Trotta, A. de Rosa, G. Inglima, M. La Commara, D. Pierroutsakou, M. Romoli, M. Sandoli INFN and University of Torino G. Pollarolo The PRISMA+CLARA collaboration F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  32. Thanks a lot F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  33. Multinucleon transfer – High Spin States population Population of high angular momentum and high excitation energy states 88Sr Nuclear Data Tables 92Zr Nuclear Data Tables F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  34. TKEL – Excitation Energy Selection Tool TKEL 92Zr Nuclear Data Tables F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  35. Pairing Vibrational States in 90Zr P.E.Garrett et al., PRC68, 024312 (2003) 1874 3308 3842 Recently completed with larger statistics Re F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  36. 64Ni+238U @ 404 MeV 53 55 -5p 57 -5n -7n -3n Yield of Vanadium isotopes 36 32 34 • N=32 shell closure previously observed in 52Ca and 54Ti • Possible N=34 shell closure theoretically predicted by the shell-model GXPF1 interaction M. Honma et al., Phys. Rev C 69, 034335(2004) Spectroscopy around N=32 shell closure F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  37. 64Ni+238U @ 404 MeV First identification of yrast states in heavy odd-A Vanadium isotopes 55V and 57V Spectroscopy around N=32 shell closure F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  38. Predicted shell closures at N=32 and N=34 N = 32 CLARA/PRISMA Gammasphere • First experimental observation of the 1f7/2 band in 55,57V • The predicted shell closure at N=34 is not confirmed by experimental data 53V 55V 57V 52Ti 54Ti 56Ti F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  39. Back of the envelope considerations. Magnetic rigidity Problems with magnetic rigidity 252Fm <q> according to Betz 208Pb • The average charge state can be very low in gas for a slow, heavy ion • for a central trajectoryPrisma is limited to A<180 • By using non-central trajectory we can reach Br=1.5Tm 176Hf 148Sm 112Sn 58Ni F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007 LNL PAC meeting 11-07-2006

  40. 1.5Tm Se Ni Ca S Back of the envelope considerations. Magnetic rigidity of Evaporation Residues Projectile and ER rigidity as a function of the target Z @ E=VB for all practical cases No reverse kinematics F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007 LNL PAC meeting 11-07-2006

  41. Reconstruction Quality Test Projectile-like Energy Resolution ~ 0.82 % Target-like F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  42. R.A.Broglia et al., Advances in NP Vol.6 (1973) W.Scobel et al., PRC30,1480(1984) 1g7/2 4 MeV 2d5/2 0 MeV 92Zr (0+) F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007

  43. pairing vibrational states 2240 1874 3308 3842 F. Scarlassara ISOLDE Workshop, CERN February 12th-15th 2007 J.B.Ball et al., PRC4,196(1971) P.E.Garrett et al., PRC68,024312(2003)

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