GAMMA-PARTICLE ARRAY FOR DIRECT REACTION STUDIES SIMULATIONS

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

Detection challenges for (d,p) reactions 78 Ni(d,p) MeV/u A Challenges: 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 Measurements->Obervables Ep and/or E  ->Ex θ p -> d σ/d  -> (l, SF) θ _lab(deg) Energy (MeV)

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

78 Ni(d,p) AMeV Particle array (Simulations)

PARTICLE ARRAY: Simple Geometry 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 X Z Y INPUT: Energy Resolution Strip pitch size Thickness detector (punch through) Target thickness effect STUDY of the  θ and  Ex

PARTICLE ARRAY: Energy Resolution Energy (MeV) θ _lab(deg) 10 keV 50 keV100 keV Energy and angle correlated -> need to fix one variable, Eproton Ep=2,3,4,5,6 MeV ->  θ and  Ex (FWHM)  E= 50 keV reasonable value

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

200 μm thick 400 μm thick μm thick ~ 40 times thicker t 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 PARTICLE ARRAY: Thickness detector

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

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

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

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

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

PARTICLE ARRAY: Excited States (target in) 79 Ni 1 MeV 2 MeV 78 Ni(d,p) 79 Ni * (Ex=1,2 MeV) 0.5 mg/cm21 mg/cm22 mg/cm2 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

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

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

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

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

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

GAMMA ARRAY: RESOLUTION: INTRINSIC  E  /E  int ~ F. Notaristefani NIM A480 (2002) Other materials: LaBr3(Ce),LaCl2 To be studied  E  /E  int ~ 50 keV

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) GAMMA ARRAY: Simple Geometry

FURTHER WORK  Study of different materials  Influence of the particle detector in the gamma detection system