NeuLAND - FAIR

200 AMeV, Erel = 100 keV
emitted
% 1n 2n 3n 4n
1n 49 25 12 4
2n 24 31 22 12
3n 7 23 25 20
4n 1 12 21 22
5n 0 4 12 19
6n 0 1 5 12
7n 0 0 2 7
8n 0 0 1 3
9n 0 0 0 1
reconstructed
1000 AMeV, Erel = 100 keV
emitted
% 1n 2n 3n 4n
1n 62 25 8 2
2n 25 39 24 11
3n 4 26 33 25
4n 0 8 23 29
5n 0 1 10 20
6n 0 0 2 10
7n 0 0 0 3
Table B.1.: Simulated multi-neutron hit capability for the MRPC-based neutron detector
with 50 layers, with the reconstruction algorithm described in the
text. Left side, 200 AMeV. Right side, 1000 AMeV. See figure B.9 for the
underlying multiplicity spectrum for 1000 AMeV.
B.6. Further MRPC Prototype and Offline Tests
The MRPC prototype SINP1 of size 40 cm × 20 cm has segmented anode strips, each strip
being 40 cm long and 2 cm wide (figure B.10). The anode strips are made of PCB with
a thin layer of gold coating and are thus almost converter free. The cathode plates were
made by introducing a thin layer of conducting material on 1 mm thick float glass. The
detector structure was housed in an aluminium chamber. Further details of the design
can be found in Ref. [Dat-10]. The detector volume of 1000 cm 3 was continuously flushed
with a gas mixture of 89% R134a, 4% sulfur hexafluoride (SF6) and 7% isobutane.
The response of the prototype has been studied extensively using cosmic-ray muons,
in coincidence with a fast inorganic scintillator detector, Cerium doped Lanthanum
Bromide (LaBr3:Ce). For the design as neutron detector we want to keep converter
material above and below the MRPC detector. List mode data of the MRPC and
LaBr3:Ce signals were taken corresponding for cosmic-ray muons and γ-rays. The master
trigger for the data acquisition was produced by a logical AND of time signals from the
MRPC and LaBr3:Ce detectors. Figure B.10 shows the TAC spectra of the MRPC in
coincidence with the LaBr3:Ce detector. The time resolution of the MRPC was measured
to be σt = 150±31 ps without slew correction. The time resolutions of the LaBr3:Ce
detector and electronics were 120 and 35 ps, respectively.
The same prototype was also studied with the ELBE pulsed electron beam. At ELBE,
after a specially designed slew correction a time resolution of σt = 92±3 ps was obtained.
All the above mentioned values for the time resolution correspond to experimental parameters
for which an absolute detection efficiency of more than 90% was obtained for
110
reconstructed