Measurement of Photoneutron Yields Using the RPI LINAC and Assessment of Evaluated Photoneutron Data for Tantalum and Beryllium

Abstract

A new experiment configuration was designed, developed, and implemented to measure photoneutron yields using the Rensselaer Polytechnic Institute (RPI) electron linear accelerator (LINAC) at the RPI Gaerttner LINAC Center. The experiment configuration includes a new target assembly that converts the LINAC electron beam into a high energy bremsstrahlung photon flux incident upon a sample material of interest. The photons excite nuclei in the sample of interest, which can subsequently emit neutrons (photoneutrons). The photoneutrons emitted in the direction of the detector system travel through a series of collimated vacuum pipes before reaching a pair of proton-recoil high-energy neutron detectors. The signals generated by the neutron detectors are processed using a digital data acquisition system and subsequently analyzed to determine the energy-dependent photoneutron yield from the sample of interest. The new experiment configuration was used to perform proof-of-concept experiments to measure the photoneutron yields from samples of tantalum and beryllium. The measured results were then compared against the results from Monte Carlo simulations of the detailed experiment configurations to perform preliminary assessments of evaluated photoneutron data libraries.