GAMMAPARTICLE ARRAY FOR DIRECT REACTION STUDIES

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GAMMA-PARTICLE ARRAY FOR DIRECT REACTION
STUDIES

• SIMULATIONS

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Detection challenges for (d,p) reactions
78Ni(d,p)79Ni _at_ 10 MeV/u
Measurements-gtObservables Ep and/or E? -gtEx ?p
-gt ds/d? -gt (l , SF)
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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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PHYSICS CASE DIRECT REACTION STUDIES
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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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132Sn(d,p)133Sn _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 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 ?? and ?Ex
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PARTICLE ARRAY Angular Resolution
If Strip pitch 1mm -gtnumber of channels for 10
cm detector 10010010000 6 detectors 6x10000
channels (pad-type detector) 6 detectors
6x(100100) channels (strip-type)
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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 _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)
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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) _at_4MeV
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PARTICLE ARRAY Excited States (no target)
132Sn(d,p)133Sn
Excitation energy resolution reconstructed from
the proton energy
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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 -gtthreshold
• Increases the ?Ep -gt difficult to separate states

0.5 mg/cm2
1 mg/cm2
2 mg/cm2
1 mg/cm2
0.5 mg/cm2
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PARTICLE ARRAY Excited States (target in)
Target thickness worsens the resolution in Ex
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PARTICLE ARRAY INTERACTION POINT

• Assuming reaction can take place at any Z lt
  Target Thickness
• X and Y are defined by the beam spot size

1 mg/cm2
1 mg/cm2 inter point
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PARTICLE ARRAY RANDOM INTERACTION POINT
The main source comes from the uncertainty on the
z-coordinate Beam spot size negligeable
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EXPERIMENTAL DATA 132Sn(d,p)133Sn at Oak Ridge
Courtesy K. JONES preliminary
160 um/cm2 target of CD2 at 4.7 MeV/u
Data will be an input for the event-generator
-gtRealistic implementation of the cross sections
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132Sn(d,p)133Sn 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 13.4 at 662 keV 90keV
Other materials LaBr3(Ce),LaCl2 To be studied
F. Notaristefani NIM A480 (2002) 423-430
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GAMMA ARRAY SIMPLE GEOMETRY

• INPUT
• Distance to (0,0,0) 5 cm
• Area 1010 cm2
• Detector Thickness 3 cm
• Source of gamma rays placed at (0,0,0)

Z
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GAMMA ARRAY Gamma resolution
Meausrement of gamma rays in coincidence with
particle is mandatory when dealing with thick
targets.
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GEOMETRY Preliminary
M. Labiche
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FURTHER WORK

• Study of different materials for the Calorimeter
• Implement realistic cross sections in the
  event-generator
• In-beam test with the TIARAMUST2EXOGAMVAMOS
  array
• Implement realistic geometry to determine
  efficiencies

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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,?)