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GAMMA-PARTICLE ARRAY FOR DIRECT REACTION STUDIES

GAMMA-PARTICLE ARRAY FOR DIRECT REACTION STUDIES. SIMULATIONS. PHYSICS CASE : DIRECT REACTION STUDIES. A. SUB-TASK: SINGLE-PARTICLES and COLLECTIVE PROPERTIES. Reactions : Elastic and inelastic scattering Transfer reactions.

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GAMMA-PARTICLE ARRAY FOR DIRECT REACTION STUDIES

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  1. GAMMA-PARTICLE ARRAY FOR DIRECT REACTION STUDIES SIMULATIONS

  2. PHYSICS CASE : DIRECT REACTION STUDIES A • SUB-TASK: SINGLE-PARTICLES and COLLECTIVE PROPERTIES • Reactions : • Elastic and inelastic scattering • Transfer reactions Integrated particle and gamma detection system : Direct reactions studies • Key experiments: Mapping of single-particle energies using transfer reactions • 78Ni(d,p)79Ni @ 10 MeV/u • 132Sn(d,p)133Sn @ 10 MeV/u

  3. Detection challenges for (d,p) reactions • 78Ni(d,p)79Ni @ 10 MeV/u Measurements->Obervables Ep and/or E ->Ex θp -> dσ/d->(l , SF) A • Challenges: Energy (MeV) • Kinematics compression ->Ep good resolution • States separated by 1 MeV ->~200 keV in Ep • Covers large range in θ_lab(deg) ->4pi ang cover • Deposit of low Energy->Threshold problems • Doppler Broadening θ_lab(deg)

  4. Particle Array Gamma Array RIBs Solid-angle of 4p PID with (Dx~0.1,0.5 mm and Dq~ 1-5 mrad) Large dynamic range with PID to Z=10 Solid-angle of 4p Best efficiency and resolution PID with (Dx~0.1,0.5 mm and Dq~ 1-5 mrad) Ancillary detectors: Spectrometer, Neutron array, … B. Integrated particle and gamma detection system : Direct reactions studies • PARTICLES TO BE DETECTED : • Beam-like particles • Spectrometer • Charged Particles • Particle Array • Gamma and fast charged particles • Gamma Array

  5. 78Ni(d,p)79Ni @ 10 AMeV Particle array (Simulations)

  6. 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 =400um • Isotropic source: protons 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

  7. PARTICLE ARRAY: Energy Resolution Energy (MeV) 10 keV 50 keV 100 keV θ_lab(deg) θ_lab(deg) θ_lab(deg) E= 50 keV reasonable value Energy and angle correlated -> need to fix one variable, Eproton Ep=2,3,4,5,6 MeV -> θ and Ex (FWHM)

  8. PARTICLE ARRAY: Angular Resolution Unnoticeable dependence with the strip sizes explored. If Strip pitch ~ 1mm ->number of channels for 10 cm detector 100*100=10000 6 detectors =6x10000 channels (pad-type detector)

  9. PARTICLE ARRAY: Thickness detector 15000 μm thick ~ 40 times thicker t 400 μm thick 200 μm thick The tickness determines the upper limit in Total energy and angle before the particles punch-through. The energy rises steadily and therefore not much gain in angular distributions

  10. PARTICLE ARRAY: Ex Resolution Ex=f(Ep,θ) Strip size small influence on the Ex resolution

  11. Y Z X PARTICLE ARRAY: Target Effect Strip pitch and thickness fixed = 1mm , 400μm Target thickness • 0.5 mg/cm2 • 1 mg/cm2 • 2 mg/cm2 • Isotropic source of protons @ (0,0,0) Effect of the angular and energy loss straggling on the θ , Ex

  12. PARTICLE ARRAY: Angular Resolution (target in) At high energies, emission angles close to 90 degrees, protons see more material

  13. PARTICLE ARRAY: Ex Resolution (target in) Ex ~ 140 keV (0.5mg/cm2) Ex ~ 170 keV (1mg/cm2) Ex ~ 225 keV (2mg/cm2) for 4MeV

  14. 2 MeV 1 MeV 79Ni PARTICLE ARRAY: Excited States (no target) 78Ni(d,p)79Ni * (Ex=1,2 MeV)

  15. 2 MeV 1 MeV 79Ni PARTICLE ARRAY: Excited States (target in) 78Ni(d,p)79Ni * (Ex=1,2 MeV) Effect of the target thickness in the Energy-Angle distributions: • Punch-through at lower Ep • Low the Ep due to the energy loss ->threshold • Increases the Ep -> difficult to separate states 0.5 mg/cm2 1 mg/cm2 2 mg/cm2

  16. PARTICLE ARRAY: Excited States (target in) Thicker target worsens the resolution in Ex

  17. FURTHER WORK • Study of the influence of the interaction point • Full geometry implementation of the integrated charge particle and gamma particle • Cross Sections implementation • Reconstruction with CsI

  18. 78Ni(d,p)79Ni at 10 AMeV Gamma array (simulations)

  19. GAMMA ARRAY: VALUES OF GAMMA RAYS IN THE LAB : DOPPLER SHIFT ~ 0.2 -> 10 AMeV E=4 MeV -> [3.4,4.8] MeV ~ 0.3 -> 35 AMeV E=4 MeV -> [2.9,5.4] MeV Θlab(degrees) E/E tot ~ E/E int + E/E dop

  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 ~ 50 keV Other materials: LaBr3(Ce),LaCl2 To be studied F. Notaristefani NIM A480 (2002) 423-430

  22. GAMMA ARRAY: Simple Geometry • Distance to (0,0,0) = 8 cm • Array of CsI detectors : • Area =10*10 cm2 • Detector Thickness = 20 cm • Isotropic source gammas 1MeV at (0,0,0)

  23. FURTHER WORK • Study of different materials • Influence of the particle detector in the gamma detection system

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