Evaluation of iron and cobalt powders as catalysts for 14C-AMS target preparation

We present an evaluation of different brands of cobalt and iron powders used to catalyze CO2 reduction for C-14-AMS graphite targets at the KCCAMS/University of California, Irvine. The optimal catalyst is characterized by rapid graphitization, homogeneity and lack of sintering of the catalyst/carbon mixture, and contains minimal amounts of both "modern" and "dead" carbon. Fifteen catalyst powders were evaluated using these criteria. The results of this study indicate three good "catalyst-candidates" with backgrounds on processed coal (Argonne Premium coal POC#3) samples around 60 ka BP and modern and dead carbon contamination of <= 0.2 mu gC for 4-5 mg of catalyst. (c) 2007 Elsevier B.V. All rights reserved.