Response Matrix for a Multisphere Spectrometer using a 6LiF Thermoluminescence Dosemeter

Using the Monte Carlo code MCNP4A, a response matrix for a multisphere spectrometer using a TLD-600 as thermal neutron detector, has been calculated for bare detector and 2, 3, 5, 8, 10 and 12 inch diameter moderating spheres. The TLD was modelled as a ribbon type TLD. Response calculations were carried out at 20 neutron energies from thermal energies to 20 MeV. A response matrix at 49 neutron energies for 25 different sphere diameters was obtained by interpolation of the calculated responses. The responses were compared with Mares and Schraube's responses for a 6LiI(Eu) scintillator-based system. The present responses have the same shape as those responses but are smaller in magnitude; this validates the use of existing LiI scintillator-based matrices for unfolding TLD-based results subject to proper normalisation. (author)