NeuLAND - FAIR

events
300
200
100
σt=0
σt=100ps
σ
=150ps
t
0
0 0.1 0.2 0.3
Erel
(MeV)
Figure 4.9.: Study of the effect of timing properties of NeuLAND on the resolution of
relative energy distributions, simulated using R 3 BRoot. Relative energy
spectra are shown for an ideal time resolution (dashed blue line), σt = 100 ps
(solid blue line), and σt = 150 ps (solid red line). One-neutron events were
emitted from 132 Sn with Erel = 100 keV at 600 AMeV. NeuLAND was
located at a distance of 35 m to the target, the scintillator cross section of
5×5 cm 2 was adopted.
The detector depth plays am important role for the efficiency of one- and more-neutron
events. The neutron recognition and its consequences with respect to the final detector
depth were investigated carefully in simulations, which are presented in section 4.5.
4.4. Light-Transport Simulations
In fast scintillator materials the time resolution is given by the number of photons and
their arrival time distribution at the photomultiplier. In this section we investigate the
effect of light guides which serve for the coupling between the quadratic cross section
of the scintillator of 5 × 5 cm to the circular entrance window of the photomultiplier.
Diameters of 1 and 1.5 inch were considered for the photomultiplier entrance window.
For the simulations the optical photon process of GEANT4 was used which allows the
definition of scintillation materials, including their properties like scintillation photon
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