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GAMMA-PARTICLE ARRAY FOR DIRECT REACTION STUDIES

GAMMA-PARTICLE ARRAY FOR DIRECT REACTION STUDIES. SIMULATIONS. Detection challenges for (d,p) reactions. 78 Ni(d,p) 79 Ni @ 10 MeV/u. Measurements->Observables Ep and/or E  ->Ex θ p -> d σ /d  -> (l , SF). A. Challenges:. Energy (MeV). Kinematics compression ->Ep good resolution

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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. Detection challenges for (d,p) reactions • 78Ni(d,p)79Ni @ 10 MeV/u Measurements->Observables 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)

  3. 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

  4. 132Sn(d,p)133Sn @ 10 AMeV Particle array (Simulations)

  5. 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

  6. PARTICLE ARRAY: Angular Resolution If Strip pitch ~ 1mm ->number of channels for 10 cm detector 100*100=10000 6 detectors =6x10000 channels (pad-type detector) 6 detectors =6x(100+100) channels (strip-type)

  7. Y Z X PARTICLE ARRAY: Target Effect Strip pitch and thickness fixed = 1mm , 300μm Target thickness • 0.5 mg/cm2 • 1 mg/cm2 • 2 mg/cm2 • Source of protons @ (0,0,0) Effect of the angular and energy loss straggling on the θ , Ex

  8. PARTICLE ARRAY: Angular Resolution (target in)

  9. PARTICLE ARRAY: Ex Resolution (target in) At high energies, emission angles close to 90 degrees, protons see more material Ex ~ 140 keV (0.5mg/cm2) Ex ~ 170 keV (1mg/cm2) Ex ~ 225 keV (2mg/cm2) @4MeV

  10. 3700 keV 2004.6 keV 1655.7 keV 1560.9 keV 853.7 keV 133Sn PARTICLE ARRAY: Excited States (no target) 132Sn(d,p)133Sn* Excitation energy resolution reconstructed from the proton energy

  11. 3700 keV 2004.6 keV 1655.7 keV 1560.9 keV 853.7 keV 133Sn PARTICLE ARRAY: Excited States (target in) 132Sn(d,p)133Sn* 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 0.5 mg/cm2 1 mg/cm2

  12. PARTICLE ARRAY: Excited States (target in) Target thickness worsens the resolution in Ex

  13. 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

  14. 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

  15. 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

  16. 132Sn(d,p)133Sn at 10 AMeV Gamma array (simulations)

  17. 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

  18. 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

  19. 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

  20. Y X GAMMA ARRAY: SIMPLE GEOMETRY INPUT: • Distance to (0,0,0) = 5 cm • Area =10*10 cm2 • Detector Thickness =3 cm • Source of gamma rays placed at (0,0,0) Z

  21. GAMMA ARRAY: Gamma resolution Meausrement of gamma rays in coincidence with particle is mandatory when dealing with thick targets.

  22. GEOMETRY : Preliminary M. Labiche

  23. FURTHER WORK • Study of different materials for the Calorimeter • Implement realistic cross sections in the event-generator • In-beam test with the TIARA+MUST2+EXOGAM+VAMOS array • Implement realistic geometry to determine efficiencies

  24. 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

  25. PARTICLE ARRAY: Ex Resolution Ex=f(Ep,θ)

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