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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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B. Fernández-Domínguez Direct Reactions at Eurisol In the light of the TIARA+MUST2campaign at GANIL
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
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.
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
Preliminary design work required:SIMULATIONS B. Fernández-Domínguez Particle Array: (energy and angular resolution) • Target Thickness • Interaction Point Gamma Array: • Scintillating material : (CsI, LaBr3)
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
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,
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)
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
B. Fernández-Domínguez TIARA+MUST2 coupled to VAMOS • Identification of the recoil • VAMOS: • Ionisation Chamber->E • Plastic ->E, TOF Drift Chambers ->X,Y,θ,
B. Fernández-Domínguez TIARA+MUST2 coupled to VAMOS +EXOGAM • Gamma detection with • EXOGAM • 4 Clovers @ 90 deg • 15% photopeak efficiency @ 1.3 MeV
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)
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)
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