Low‐Energy Grazing Ion‐Scattering From Alkali‐Halide Surfaces: A Novel Approach To C‐14 Detection

Carbon‐14 labeled compounds are widely used in the pharmaceutical industry, e.g., as tracers to determine the fate of these compounds in vivo. Conventional accelerator mass spectrometry (AMS) is one approach that offers sufficiently high sensitivity to avoid radiological waste and contamination issues in such studies, but requires large, expensive facilities that are usually not solely dedicated to this task. At the ORNL Multicharged Ion Research Facility (MIRF) we are exploring a small size, low cost alternative to AMS for biomedical 14C tracer studies that utilizes ECR‐ion‐source‐generated keV‐energy‐range multicharged C beams grazingly incident on an alkali halide target, where efficient negative ion production by multiple electron capture takes place. By using C ion charge states of +3 or higher, the molecular isobar interference at mass 14, e.g. 12CH2 and 13CH, is eliminated. The negatively charged ions in the beam scattered from the alkali halide surface are separated from other scattered charge sta...