First results of the MAGNEX large-acceptance spectrometer

1. First results of the MAGNEX large-acceptance spectrometer F.Cappuzzello LEA COLLIGA October 13-15, LNS (Catania)

2. A.Cunsolo, F.Cappuzzello, M.Cavallaro, A.Foti, S.E.A.Orrigo, M.R.D.Rodrigues INFN-LNS, Catania, Italy INFN, Sez. Catania, Catania, Italy Università di Catania, Catania, Italy A.Bonaccorso, T.Borello, P.Guazzoni, H.Lenske, H.Petrascu, C.L.Rodrigues, J.S.Winfield, L.Zetta INFN, Sez. Pisa, Pisa, and Sez. Milano, Milano, Italy University of S. Paulo, IFUSP, Brazil Universitatat Giessen, Giessen, Germany NIPNE, Bucarest, Romania GSI, Darmstadt, Germany The MAGNEX collaboration

3. Topics • The MAGNEX spectrometer • Planned experiments • First results from the initial experiments

4. MAGNEX E <30 AMeV 2 < A < 40 E < 25 AMeV 40 < A < 93 Upper bent limits A.Cunsolo et al., NIMA 481 (2002) 48 A.Cunsolo et al., NIMA 484 (2002) 56

5. Ray-trace spectrometer • Possible definition: spectrometer based on the solution of the equation of motion of each single detected particle Practically one needs • Detailed knowledge of the magnetic field maps • Algorithms for high order solution of equation of motion and inversion of transport matrices • Detectorsto measure positions and angles at the focus • V.A.Shchepunov et al., NIMB 204 (2003) 447 • A.Lazzaro et al.,I.P.C.S.175 (2005) 171 • A.Lazzaro et al., NIMA 570 (2007) 192 • A.Cunsolo et al., E.P.J. 150 (2007) 343 • A.Lazzaro et al., NIMA 585 (2008) 136 • A.Lazzaro et al., NIMA 591 (2008) 394 • P.Guazzoni et al., IEEE accepted

6. Initial commissioning • Initial commissioning means a series of tests with different beams and targets with a small scattering chamber • Limit of the fixed angle at 255 • Limit of the beam energy (10 MV High Voltage on Tandem terminals)

7. Alpha source at the target-object pointMAGNEX in large acceptance mode Counts _foc (rad) -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 -0.5 -0.4 -0.3 -0.2 -0.1 0 0.1 0.2 0.3 0.4 0.5 X_foc (m) X_foc (m)

8. 100 10-1 10-2 10-3 13 14 15 16 17 18 19 20 21 Logfraction 48Ti + 197Au elastic scattering at 120 MeV Momentum dispersion 2 measurements of Xfoc with same magnet settings but with 48Ti beam energy changed by 2.6% Result: 3.68 cm/% for K = -0.1 Charge State distribution(diamonds) Agreement with results from INTENSITY calculations (triangles) J.A.Winger et al., Nucl. Instr. Meth. B 70 (1992) 380

9. elastic scattering Measure of ivia trajectory reconstruction 16O + 58Ni  16O + 58Ni at 80 MeV FWHM  10 mr Consistent with the holes size 16O beam MAGNEX black box Counts Diaphragm (1-mm holes) 58Ni target i (rad) DWBA calculations

10. Experimental lines • Spectroscopy of ligth neutron rich nuclei via the CEX reaction (7Li,7Be) at Tandem energies • Experiments with quasi stable 14C (18 O) Tandem beams • Spectroscopic studies of heavy ions via (p,t) direct 2n pick-up and via (6Li,d) -transfer (next month) • 8He spectroscopy via the 7Li(8Li,7Be)8He ( EXCYT beam) at 52 MeV • Experiments of nuclear astrophysics (Trojan Horse Method) • Experiments with the LNS K800 Superconducting Cyclotron beams (e.g. pionic fusion at subthreshold energies)

11. Ligth neutron rich nuclei Spectroscopy via the (7Li,7Be) CEX reaction First measurements (December 2007) • Targets : AlF3, 27Al and 12C, • Final Nuclei : 19O and 27Mg, • Beam energy 52 MeV, • Data under reduction.

12. 19F(7Li,7Be)19O at Einc = 52,4 MeV E/E  1000 • Lab = 7 19.5 • = 50 msr Energy byte =  27% 19.8 keV/ch gs 96 keV 19O PRELIMINARY (~10% statistics) Counts

13. Multi-neutron transfer by 18 O Tandem beams First Experiment (January 2008) • Target: 13C 100 g/cm2 • Selected reaction channels (18O,17O) (18O,16O) (18O,15O) • Reasidual nuclei 14C, 15C and 16C • Beam energy 84 MeV, • Data under reduction.

14. PRELIMINARY Yf (m) g.s. 0.74 4.22 18O 6+ 18O 8+ 17O 8+ Xf (m) PRELIMINARY Xf(m) 15O 8+ 16O 8+ 18O 7+ Er Residual energy (MeV) 13C(18O,16O)15C at Einc = 84 MeV • Lab = 7 19.5 • = 50 msr Energy byte =  27% Particle identification without TOF Not reconstructed focal plane position spectrum

15. Conclusions • MAGNEX has successfully started its experimental program (first experiment December 2007). • Other two experiments already performed 13C(18O, 16,15O)15,16C on January 2008 and 28Si(7Li,7Be)28Al on July 2008. • A new experiment is scheduled next month. • The results coming out from data analysis are very encouraging

16. Inversion of transport matrices • Large acceptance condition • For MAGNEX up to 11th order ! • Differential algebra (Ex:COSY INFINITY)M. Berz et al., PRC 47 (1993) 537 f instead of i for MAGNEX Iterative formula for the inverse matrix

17. The PSD start detector -channel Gassiplex motherboards Pads

18. Ion The FPD detector A.Cunsolo et al., NIMA 495 (2002) 216 • Trapezoidal geometry • Window length 92 cm. Height 20 cm. Depth 16 cm • Isobutane pressurebetween 5 e 50 mbar • Energy threshold down to 0.5 MeV/amu • No intermediatefoils • Maximum counting rate 4 kHz

19. Reconstructing trajectories ANGULAR AND MASS RESOLUTION • Angular and mass resolution are ~ ion-independent 6Li + 12C (100 g/cm2) 6Li + 12C (100 g/cm2) ◆1.8 Tm  ~ 38 MeVu ■1.06 Tm  ~13 MeVu ▲ 0.5 Tm  ~ 3 MeV/u

20. Reconstructing trajectories Energy resolving power for 6Li + 12C (100 g/cm2) A.Lazzaro et al. 7th ICAP, East Lansing, 2002, IOP series 175, pagg. 171-180 LNS Tandem ◆1.8 Tm  ~ 38 MeVu a) ■ 1.06 Tm  ~13 MeVu a) ▲0.5 Tm  ~ 3 MeV/u b) ● 0.815 Tm  8 MeV/u b) • LNS – Cyclotron energies • LNS - Tandem energies

21. DE [MeV] 9Be 1 7Be Z = 3 Z = 2 Eres [MeV] DE [MeV] 2 7Be Eres [MeV] 7Li + AlF3 l = 25°  5° El = 40.2 MeV

22. 7Li + AlF3, l = 25°  5°, El = 40.2 MeV TOF [msec] 7Be 1 9Be xfoc [m] TOF [msec] 7Be 2 xfoc [m]