NeuLAND - FAIR

B.7. MRPC Solution using Glass as Converter
As an alternative, a new concept for the detection of high energy neutrons based on
RPC’s was also proposed. This concept considers only glass as converter material.
There is no iron in the whole detector.
Based on a modular geometry, each RPC module contains a certain number of glass
electrodes separated by 300 µm, operated in a standard gas mixture. The gas gaps are
encapsulated in a gas tight plastic box, which only contains feed-throughs for the active
gas (a standard mixture of 90% freon and 10% SF6) and the high voltage. The readout
strips are allocated outside the plastic box. The whole system is electrically isolated by
a metallic shielding. Based on simulation studies using the R 3 BROOT framework, the
thickness of the glass plates has been chosen to be 3 mm [Mac-11]. A schematic view
of the iron-less RPC concept is shown in the left panel of figure B.11. A RPC module
(100 cm × 50 cm) based on the iron-less RPC concept already exists at LIP-Coimbra,
and it can be seen in the right panel of figure B.11.
Metallic shielding
Figure B.11.: Schematic drawing (left) and photograph (right) of the iron-less RPC module
with the readout electrodes.
A number of up to 8 modules with dimensions 200 × 50 cm is presently under construction
at LIP-Coimbra. The performance of this new concept in the detection of high
energy neutrons will be tested during the allocated deuteron break-up experiment at the
R 3 B setup during 2012.
B.8. Summary and Outlook
The development of the MRPC option for NeuLAND provided many valuable insights.
One of the largest area MRPC structures ever built was developed for the purpose, and
it was unambiguosly shown that the structure will even work as an MRPC in its strongly
modified form using thick passive converters.
The first MRPC-based neutron detector we are aware of has been built, and it was
shown that an MRPC-based detection concept can work for 1 GeV neutrons. Also, the
Neutron MRPC development for NeuLAND was an important driver in the development
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