Deuteron irradiation of W and WO3 for production of high specific activity (186)Re: Challenges associated with thick target preparation

Ethan R Balkin; Katherine Gagnon; Kevin T Strong; Bennett E Smith; Eric F Dorman; Robert C Emery; Peter J Pauzauskie; Michael E Fassbender; Cathy S Cutler; Alan R Ketring; Silvia S Jurisson; D Scott Wilbur

doi:10.1016/j.apradiso.2016.06.021

Deuteron irradiation of W and WO3 for production of high specific activity (186)Re: Challenges associated with thick target preparation

Appl Radiat Isot. 2016 Sep:115:197-207. doi: 10.1016/j.apradiso.2016.06.021. Epub 2016 Jun 28.

Authors

Affiliations

¹ Department of Radiation Oncology, University of Washington, Seattle, WA 98195, USA.
² Department of Radiation Oncology, University of Washington, Seattle, WA 98195, USA; Department of Oncology, Cross Cancer Institute, University of Alberta, Edmonton, Alberta, Canada T6H 5Y1.
³ Materials Science and Engineering Department, University of Washington, Seattle, WA 98195, USA.
⁴ Chemistry Department, University of Washington, Seattle, WA 98195, USA.
⁵ Los Alamos National Laboratory, Los Alamos, NM 87545, USA.
⁶ Collider-Accelerator Department, Brookhaven National Laboratory, Upton, NY 11973, USA; University of Missouri Research Reactor Center, Columbia, MO 65211, USA.
⁷ University of Missouri Research Reactor Center, Columbia, MO 65211, USA.
⁸ Department of Chemistry, University of Missouri, Columbia, MO 65211, USA.
⁹ Department of Radiation Oncology, University of Washington, Seattle, WA 98195, USA. Electronic address: dswilbur@uw.edu.

PMID: 27423020
DOI: 10.1016/j.apradiso.2016.06.021

Abstract

This investigation evaluated target fabrication and beam parameters for scale-up production of high specific activity (186)Re using deuteron irradiation of enriched (186)W via the (186)W(d,2n)(186)Re reaction. Thick W and WO3 targets were prepared, characterized and evaluated in deuteron irradiations. Full-thickness targets, as determined using SRIM, were prepared by uniaxially pressing powdered natural abundance W and WO3, or 96.86% enriched (186)W, into Al target supports. Alternatively, thick targets were prepared by pressing (186)W between two layers of graphite powder or by placing pre-sintered (1105°C, 12h) natural abundance WO3 pellets into an Al target support. Assessments of structural integrity were made on each target prepared. Prior to irradiation, material composition analyses were conducted using SEM, XRD, and Raman spectroscopy. Within a minimum of 24h post irradiation, gamma-ray spectroscopy was performed on all targets to assess production yields and radionuclidic byproducts. Problems were encountered with the structural integrity of some pressed W and WO3 pellets before and during irradiation, and target material characterization results could be correlated with the structural integrity of the pressed target pellets. Under the conditions studied, the findings suggest that all WO3 targets prepared and studied were unacceptable. By contrast, (186)W metal was found to be a viable target material for (186)Re production. Thick targets prepared with powdered (186)W pressed between layers of graphite provided a particularly robust target configuration.

Keywords: (186)Re production; Deuteron induced reaction; High specific activity; Pressed targets; W and WO(3) thick targets.