title: Parts per billion doping and characterization of uranium distribution in an epoxy polymer matrix.
abstract: Formulating an epoxy polymer provides a broadly applicable method for homogeneously doping a chemically stable, particulate-resistant, and radiation-hardened matrix with virtually any trace elements of interest. In the example reported, control of uranium levels over the range, 15 microg/g-15 ng/g, is demonstrated. Fission track density determinations, referenced to NIST SRMs, indicate +/-5% variations in lateral uranium distributions. Determinations of levels of uranium impurities in commercially available high-purity samples of graphite, fused silica, and aluminum show respective nanogram per gram ranges of 3 +/- 0.1-5 +/- 0.3, 3 +/- 0.8-27 +/- 2, and 113 +/- 11-546 +/- 11. The prepared polymer materials cover 3 orders of magnitude of uranium levels in an ideal matrix. This accomplishes the prerequisite for subsequent investigations of the chemistry occurring at fission fragment-induced damage sites of selected track registering materials as a function of controlled reactive site densities. The matrix also serves as a source of swift heavy ions for creating nanoscale features in dielectric materials.
authors.affiliation: CREST Nanomaterials Characterization Science Center, Howard University, Washington, D.C. 20059, USA. jwm@msrce.howard.edu
authors.forename: James W
authors.initials: JW
authors.lastname: Mitchell
authors.forename: Steve
authors.initials: S
authors.lastname: Carpenter