This article reviews the design and operation of a transportable neutron sp
ectrometer. Four of these instruments were produced and have been widely us
ed for applications such as the assessment and classification of radiation
hazards at field sites in the United Kingdom and Europe. An overview of the
instrument hardware is presented, together with a description of the six s
ensor channels, their associated processing electronics and the host data l
ogger computer. Spectral unfolding is also summarized and a sample spectra,
which was measured from outside a fuel flask, is given. (C) 2001 American
Institute of Physics.