An insight into neutron detection from polycrystalline CVD diamond films

Radiation detectors fabricated from chemical vapour deposited (CVD) diamond have now been fabricated addressing several photon and particle detectors in the frame of specific industrial applications. Regarding the nuclear industry needs, diamond-based detectors have been fabricated and this paper presents the various techniques that can be of interest for the detection of fission neutrons. The ability of diamond to withstand the high irradiation fluxes as encountered in nuclear reactors is one of the motivations. Of the few techniques that are presented here, one approach relies on the use of converting materials, i.e. elements on which a nuclear reaction gives rise to the creation of charge particles that could be detected. Boron and particularly B-10 has been used successfully. Other techniques are also presented including detection in the current mode from the elastic scattering of fission neutrons in diamond, as well as an approach where the boron material is inserted directly inside the material in the form of a dopant. From the material irradiation in neutron fluxes from a nuclear reactor, the modification of the material property was characterised, and particularly the modification due to the progressive effect of transmutation of B-10 dopant elements. This particular feature may enable the fabrication of passive (off-line detection devices). The approaches will be discussed in terms of the advantages and drawbacks of the techniques. (C) 2003 Elsevier B.V. All rights reserved.