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Direct Reactions at Eurisol

B. Fern ández-Domínguez. Direct Reactions at Eurisol. In the light of the TIARA+MUST2 campaign at GANIL. B. Fern ández-Domínguez. Physics Motivation. EURISOL FW5 report : SCIENTIFIC CASE (Appendix A):.

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Direct Reactions at Eurisol

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  1. B. Fernández-Domínguez Direct Reactions at Eurisol In the light of the TIARA+MUST2campaign at GANIL

  2. B. Fernández-Domínguez Physics Motivation EURISOL FW5 report : SCIENTIFIC CASE (Appendix A): Direct reactions are a unique tool to uncover and investigate new manifestations of nuclear structure of exotic nuclei • Elastic and inelastic scattering -> nuclear and transition densities • Transfer, knock-out and break-up reactions -> microscopic shell-structure • Inverse kinematics • Detection: • light charged particles • gamma-rays • neutrons • beam-like particles

  3. Instrumentation for Direct Reactions B. Fernández-Domínguez EURISOL FW5 report : INSTRUMENTATION (Appendix E): Array for light charged-particle and gamma-array measurements: GRAPA(Gamma-Ray And Particle Array) Updated version: http://ns.ph.liv.ac.uk/eurisol/spec_expts/M2.1_apparatus.pdf • Charged Particles: (Particle Array ) Solid-angle of 4 x~0.1,0.5 mm and θ~ 1-5 mrad Large dynamic range with PID to Z=10 RIB • Gamma and fast charged particles : (Gamma Array) Solid-angle of 4 Best efficiency and resolution Integration of cryogenic and polarised targets.

  4. Preliminary design work required 3700 keV 2004.6 keV 1655.7 keV 1560.9 keV 853.7 keV 133Sn B. Fernández-Domínguez - SIMULATIONS: Modelling of a number of potential key experiments proposed, study different configurations etc… - IN-BEAM TEST TO VALIDATE DESIGN CHOICES: To asses the methodology and feasibility of the design concept. SIMULATIONS: • Key experiments: • 78Ni(d,p)79Ni @ 10 MeV/u • 132Sn(d,p)133Sn @ 10 MeV/u

  5. Preliminary design work required:SIMULATIONS B. Fernández-Domínguez Particle Array: (energy and angular resolution) • Target Thickness • Interaction Point Gamma Array: • Scintillating material : (CsI, LaBr3)

  6. Preliminary design work required:IN-BEAM TESTS B. Fernández-Domínguez TIARA-MUST2 CAMPAIGN AT SPIRAL/GANIL September – November 2007 -Si-array ->Array of silicon detectors covering 90% of 4pi. MUST2 and TIARA -Ge-array->EXOGAM -Spectrometer ->VAMOS Large step towards an integrated particle-gamma ray array. Results can be used to validate the design choices of the new EURISOL array (d,p) with 20O and 26Ne beams at SPIRAL : Study of the N=16 shell gap 20O-> Location of the d3/2 state in Oxygen neutron rich isotopes 26Ne->Reveal isomeric f7/2 intruder that competes with sd ground state

  7. Preliminary design work required:IN-BEAM TESTS B. Fernández-Domínguez EXOGAM Gamma-ray array MUST2 Si-CsI VAMOS spectrometer GANIL radioactive beam - 20O (SPIRAL) 10.9 A MeV 104 pps TIARA silicon array Triple coincidences: Target-like particles – TIARA/MUST2 Beam-like particles - VAMOS Gammas - EXOGAM Trigger: hit in Si-detector CD2 target 0.5 mg/cm2 Detectors E, E, TOF B, 

  8. B. Fernández-Domínguez TIARA: Inner and Outer Barrel +Hyball TIARA – Two Barrels: 8 detectors, x 4 longitudinal strips each. -Inner Barrel-> Energy, position. (E~ 200 keV, θ~1-2 deg) -Outer Barrel- identification. (30-140 deg) - Hyball, 6 wedges, x16 rings (radial), x 8 sectors (azimutal) (E~ 50 keV, θ~2 deg) (150-175 deg)

  9. B. Fernández-Domínguez MUST2: 4 Telescopes of Si+CsI MUST2 4 telescopes of Si-CsI placed at forward angles. (0-30 deg) Si-Strip – 4 modules x128x128 Energy, position. E~ 50 keV, θ~0.22 deg (pitch size 0.7mm at 180 mm) CsI- 4 modules with 4x4 crystals Identification E-E

  10. B. Fernández-Domínguez TIARA+MUST2 coupled to VAMOS • Identification of the recoil • VAMOS: • Ionisation Chamber->E • Plastic ->E, TOF Drift Chambers ->X,Y,θ,

  11. B. Fernández-Domínguez TIARA+MUST2 coupled to VAMOS +EXOGAM • Gamma detection with • EXOGAM • 4 Clovers @ 90 deg • 15% photopeak efficiency @ 1.3 MeV

  12. E (MeV) g.s 1st 1.28 MeV (d,p) θ (degrees) BOUND STATES E (MeV) SIMULATION Geant4 g.s θ (degrees) B. Fernández-Domínguez SPIRAL: RADIOACTIVE BEAM of 20O: d(20O,p)21O  21O + Preliminary (on-line results)

  13. E (MeV) (d,p) θ (degrees) UNBOUND STATES E (MeV) SIMULATION Geant4 E (keV) θ (degrees) B. Fernández-Domínguez SPIRAL: RADIOACTIVE BEAM of 20O: d(20O,p)21O  20O +n Preliminary (on-line results)

  14. SUMMARY • Simulations reproduce response of arrays and give insight into the main parameters that contribute to performance • Online analysis of the experiment confirms we can study different reactions channels, obtain level energies and l-values information • The feasibility of the methodology is demonstrated. • transfer to bound and unbound states with full channel identification • triple coincidences with excellent gamma energy resolution • also have (d,d’) and (d,t) acquired simultaneously with TIARA and MUST2 • to include unbound states requires the large VAMOS angle/momentum bite • type of experiments will be important to learn for the future array. FUTURE • Increase efficiency of particle-gamma coincidences.. • Gamma detection better efficiency, allow for fast-particle detection simultaneously • Improve performance of particle array. (Energy resolution, low thresholds) • Possibility to introduce cryogenic or polarised targets

  15. No part of the talk end

  16. Y Z X PARTICLE ARRAY: Simple Geometry INPUT: • Distance to (0,0,0) = 5 cm • Box of 4 Silicon detectors : • Area =10*10 cm2 • Detector Thickness =300um • Source of protons with kinematics from reaction placed at (0,0,0) • No target • Energy Resolution • Strip pitch size • Thickness detector (punch through) • Target thickness effect STUDY of the θ and Ex

  17. PARTICLE ARRAY: INTERACTION POINT • Assuming reaction can take place at any Z < Target Thickness • X and Y are defined by the beam spot size 1 mg/cm2 1 mg/cm2 +inter point

  18. 3700 keV 2004.6 keV 1655.7 keV 1560.9 keV 853.7 keV 133Sn PARTICLE ARRAY: RANDOM INTERACTION POINT The main source comes from the uncertainty on the z-coordinate Beam spot size negligeable

  19. EXPERIMENTAL DATA: 132Sn(d,p)133Sn at Oak Ridge 160 um/cm2 target of CD2 at 4.7 MeV/u Courtesy K. JONES preliminary Data will be an input for the event-generator ->Realistic implementation of the cross sections

  20. GAMMA ARRAY: RESOLUTION: DOPPLER BROADENING E lab = f(θ,) -> E/E dop ~ f(θ) E/E (%) E/E ~ 0.5 % E=1MeV -> 5 keV θ~ 2o D=8 cm Crystal Sizeθ 2.8 mm 2o Θlab(degrees) 3mm for a detector size of 12cm ->40x40 =1600 ch detector 6 detectors ->6x 1600=9600 channels

  21. GAMMA ARRAY: RESOLUTION: INTRINSIC E/E int ~ E/E int ~ 13.4 % at 662 keV ~ 90keV Other materials: LaBr3(Ce),LaCl2 To be studied F. Notaristefani NIM A480 (2002) 423-430

  22. 2.1 TRANSFER 24Ne(d,pg)25Ne : Systematics of the 3/2+ in the N=15 isotones + 27Mg 23O 25Ne 4.5 4.0 1f7/2 3.5 3.0 2.5 excitation energy (MeV) 2.0 1d5/2 1.5 1d3/2 1.0 0.5 2s1/2 0.0 8 10 12 6 atomic number • 23O from USD shell model and M.Stanoiu et al., PRC 69 (2004) 034312. • 25Ne preliminary result. The energy of the 1d3/2 neutron orbital rises when protons are removed from its spin-orbit partner, the 1d5/2 orbital.

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