Download Transfer reactions Resonant Elastic scattering Inelastic scattering: GR

Transfer reactions
Resonant Elastic scattering
Inelastic scattering: GR
Transfer reactions
77Ni(d,p)78Ni
at 10 MeV/u
qcm=1.5, 20, 40°
Cell of 50cm length side, cubic or cylindric
Beam shield 1cm wide (±5mm)
qlab
Transfer reactions
Beam
Beam
and B
x
Trajectory
B
q
Beam
Transfer reactions
Conclusions
-Forward angles most difficult
-Better energy resolution obtained with cubic geometry and B
But
-Deviation of the beam
-trajectories crossing the beam
Best design: cylindric detector with B parallel to the beam
and longitudinal projection
Resonant Elastic scattering
Eres=Ecb-Sn+Ex
Case 77Ni: Eres=5MeV
Typical energy range to cover: 4 to 9 MeV
Resonant Elastic scattering
For angles below 10°, energy resolution dominated by the
position resolution at the reaction place
MAYA geometry: reaction place determined by projection on anode plane.
Limitation to  between ±45°. Loss of solid angle (factor 2 or 4).
Cylindric geometry: position determined by time resolution. Problem also at
small angles: for 5°, with interstrip=2mm, resolution ≈ 1mm. Problem with
increase of rise time???
Inelastic scattering: Giant resonances
Very low energy recoil
Particles =>no impurities
Pure gases H2,D2
Track length>5cm
P≈100mb
Charge state fluctuations???
Inelastic scattering: Giant resonances
Plane geometry
Cylindric geometry
Conclusions
— Large dynamics needed: 0.2-20 MeV
— Either magnetic field or ancillary detectors (many)
— Energy resolution:
50 keV for Si detectors
=>10% at 0.5 MeV, 0.5% at 5 MeV
Position resolution 0.25mm
=>2.5% for 1cm, 0.25% for 10cm
—Cubic geometry :
Problem with deflection of the beam in with B
Solid angle reduced by factor 2(4)
—Cylindric geometry:
Problem at small angles (ancillary detectors below 5°)
Varying rise times of the pulses