GAMMA-PARTICLE ARRAY FOR DIRECT REACTION STUDIES

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GAMMA-PARTICLE ARRAY FOR DIRECT REACTION
STUDIES

• SIMULATIONS

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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 _at_ 10 MeV/u
• 132Sn(d,p)133Sn _at_ 10 MeV/u

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Detection challenges for (d,p) reactions
78Ni(d,p)79Ni _at_ 10 MeV/u
Measurements-gtObervables Ep and/or E? -gtEx ?p -gt
ds/d? -gt (l , SF)
A
Challenges
Energy (MeV)

• Kinematics compression -gtEp good resolution
• States separated by 1 MeV -gt200 keV in Ep
• Covers large range in ?_lab(deg) -gt4pi ang cover
• Deposit of low Energy-gtThreshold problems
• Doppler Broadening

?_lab(deg)
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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

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78Ni(d,p)79Ni _at_ 10 AMeV

• Particle array (Simulations)

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PARTICLE ARRAY Simple Geometry
INPUT

• Distance to (0,0,0) 5 cm
• Box of 4 Silicon detectors
• Area 1010 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 ?? and ?Ex
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PARTICLE ARRAY Energy Resolution
Energy (MeV)
10 keV
50 keV
100 keV
?_lab(deg)
?_lab(deg)
?_lab(deg)
?E 50 keV reasonable value
Energy and angle correlated -gt need to fix one
variable, Eproton Ep2,3,4,5,6 MeV -gt ?? and
?Ex (FWHM)
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PARTICLE ARRAY Angular Resolution
Unnoticeable dependence with the strip sizes
explored. If Strip pitch 1mm -gtnumber of
channels for 10 cm detector 10010010000 6
detectors 6x10000 channels (pad-type detector)
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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
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PARTICLE ARRAY Ex Resolution
Exf(Ep,?)
Strip size small influence on the Ex resolution
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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 _at_ (0,0,0)

Effect of the angular and energy loss straggling
on the ?? , ?Ex
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PARTICLE ARRAY Angular Resolution (target in)
At high energies, emission angles close to 90
degrees, protons see more material
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PARTICLE ARRAY Ex Resolution (target in)
?Ex 140 keV (0.5mg/cm2) ?Ex 170 keV
(1mg/cm2) ?Ex 225 keV (2mg/cm2) for 4MeV
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PARTICLE ARRAY Excited States (no target)
78Ni(d,p)79Ni (Ex1,2 MeV)
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PARTICLE ARRAY Excited States (target in)
78Ni(d,p)79Ni (Ex1,2 MeV)

• Effect of the target thickness in the
  Energy-Angle distributions
• Punch-through at lower Ep
• Low the Ep due to the energy loss -gtthreshold
• Increases the ?Ep -gt difficult to separate states

0.5 mg/cm2
1 mg/cm2
2 mg/cm2
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PARTICLE ARRAY Excited States (target in)
Thicker target worsens the resolution in Ex
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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

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78Ni(d,p)79Ni at 10 AMeV

• Gamma array (simulations)

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GAMMA ARRAY VALUES OF GAMMA RAYS IN THE LAB
DOPPLER SHIFT
? 0.2 -gt 10 AMeV E?4 MeV -gt 3.4,4.8 MeV ?
0.3 -gt 35 AMeV E?4 MeV -gt 2.9,5.4 MeV
Tlab(degrees)
?E?/E? tot ?E?/E? int ?E?/E? dop
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GAMMA ARRAY RESOLUTION DOPPLER BROADENING
E ?lab f(?,?) -gt ?E?/E? dop f(?)
?E?/E? ()
?E?/E? 0.5 E1MeV -gt 5 keV ?? 2o D8
cm Crystal Size ?? 2.8 mm 2o
Tlab(degrees)
3mm for a detector size of 12cm -gt40x40 1600 ch
detector 6 detectors -gt6x 16009600 channels
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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
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GAMMA ARRAY Simple Geometry

• Distance to (0,0,0) 8 cm
• Array of CsI detectors
• Area 1010 cm2
• Detector Thickness 20 cm
• Isotropic source gammas 1MeV at (0,0,0)

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FURTHER WORK

• Study of different materials
• Influence of the particle detector in the gamma
  detection system