Characterizing Secondary Neutrons at BLIP for Isotope Production Applications

TL;DR

This study characterizes secondary neutrons at BLIP using experimental foil activation and Monte Carlo simulations, optimizing configurations to enhance neutron yield for isotope production.

Contribution

It introduces a combined experimental and simulation approach to optimize secondary neutron yield at BLIP for isotope production applications.

Findings

Simulations agree with measurements within 9% after spectral adjustment.

Closest proximity of N-slot to proton degrader yields highest neutron flux.

Tungsten degraders outperform other materials in neutron yield enhancement.

Abstract

Fast secondary neutrons created at the Brookhaven Linac Isotope Producer (BLIP) facility following proton irradiation were characterized by the foil activation technique and compared with FLUKA Monte Carlo simulations. The FLUKA-simulated neutron flux was spectrally adjusted following the maximum entropy formalism using the International Reactor Dosimetry and Fusion File (IRDFF-II), with predictions agreeing with experimental measurements to within 9% following the adjustment procedure. A multitude of degrader configurations were simulated to assess the feasibility of improving the fast (En > 20 MeV) secondary neutron yield at the proposed neutron target position (N-slot). A configuration where the N-slot is closest to the proton degrader produced the highest fast neutron yield, with tungsten degraders achieving the best performance. Assuming the optimized target-degrader configuration proposed in this work, we discuss potential isotope production opportunities with secondary neutrons. In most cases the yields are in the order of several mCi.