Neutron spectral measurement of the Ohio state research reactor pneumatic tube

Pneumatic irradiation facilities are used for neutron activation analysis, materials testing, electronics hardening, and radioisotope production. The application of these facilities can benefit from a greater understanding of the neutron energy profile inside the irradiation cavities as often only the cadmium ratio is known. A program to measure the energy-dependent neutron fields inside the pneumatic tube at the Ohio State University Research Reactor was undertaken using wires consisting of thermal activation materials and threshold reaction materials with and without thermal and resonance absorbers surrounding them. The measured activities were unfolded using the MAXED unfolding code to reconstruct the neutron energy spectra and compared to the MCNP-calculated flux.