Improving accuracy, precision, detection limits, and sample throughput in prompt gamma-ray activation analysis using cold and thermal neutrons and element ratios

A combination of thermal neutron (TN) and cold neutron (CN) prompt gamma-ray activation analysis (PGAA) has been used to lower analytical bias, to improve precision and detection limits, and to reduce sample throughput time. CNPGAA was used to measure element ratios relative to a comparator element, while TNPGAA was used to measure the comparator element. Low-Z elements with normally poor sensitivity (C, N, and S) were measured with expanded uncertainties of<2% in coal and fuel oil using H as comparator element. Using the combined method, measurements can be made with good counting statistics in a fraction of the time needed for TNPGAA alone, with a 20-30-fold improvement in detection limits.