Conceptual design for a scintillating-fiber neutron detector for fusion reactor plasma diagnostics

摘要

A conceptual design for a ''pointing'' neutron detector that is capable of delivering 10(sup 4) - 10(sup 5) Hz countrate of T(D,n) events from triton burnup at a deuterium-burning tokamak is described. The detector consists of collimated bundles of scintillating fibers that are separated by metal or polyethylene. These bundles in turn are set into a larger collimator that has some of the bundles set in ''unplugged'' holes and others in ''plugged'' holes whose countrate difference gives the net countrate. It is computed that the use of a 6 MeV(sub ee) (electron equivalent) discriminator will allow 14-MeV neutron countrates of 2xl0(sup 4) Hz in a DD machine or 3 MHz in a DT machine, while effectively rejecting the gamma background. The efficiency-area product for 14-MeV neutrons will be (similar to) 0.014 cm(sup 2). The angular resolution is computed to be 4.5(degree) HWHM for a 35 cm long collimator.