A fast neutron spectrometer

A fast neutron spectrometer was designed and constructed using a proton-recoil telescope. Recoil protons from a thin foil of polyethylene were detected with a silicon surface-barrier diode. The output pulse from the detector is proportional to the energy of the protons and hence the energy of the incident neutrons. The spectrometer was used to obtain pulse height spectra from various sources of fast neutrons including the V.P.I. reactor and the d-d reaction using the Cockroft-Walton accelerator.

Results obtained indicate that for high intensity sources the spectrometer is capable of providing high resolution energy spectra although modification is necessary in some cases to reduce background. The compactness of the instrument and its simplicity make it ideal for investigating sources that are not readily amenable to other techniques.