  The production of flexible and robust thermal neutron detectors with improved
properties as compared to the commercial ZnS:Ag based phosphors is here
pursued, exploiting a siloxane binder, whose intrinsic properties as related to
the chemical features of the functional groups and to the optical properties
are investigated and tailored in correlation with the final performances of the
detectors. Two different siloxanes either with pendant phenyl groups or with
aliphatic groups have been used, the former being intrinsically fluorescent and
with higher polarizability than the latter. Moreover, 6LiF crystals have been
synthesized by co-precipitation method and the solvent/co-solvent ratio has
been changed in order to tune the crystal size. Then, the size effect on the
detector efficiency to thermal neutrons has been investigated as related to the
energy loss of thermal neutron reaction products inside the crystal and the
dispersion homogeneity of the crystals into the composite. To complete the
characterization of the produced flexible detectors, the response to
{\gamma}-rays has been measured and compared to a commercial detector. The
careful choice of both the base resin and the 6LiF crystals size allows to
produce flexible detector for thermal neutrons with performances comparable to
the commercial standard and with higher mechanical robustness and stability.
