Experiences with a PFN Uranium Logging System

The Prompt Fission Neutron (PFN) uranium logging system has been used by Sandia National Laboratories for field operations for about six years; during that time, the system has been used at several exploration sites from southern Texas to Wyoming. Some of the improvements, recent changes to the system, and new applications are discussed here. A high-voltage doubler has been designed for the neutron generator which permits operation at pulse rates of up to one kHz. Other improvements in hardware have also been made. The PFN tool has been tested at moderately elevated temperatures (~93°C). The tool has been used in support of the Uranium Mill Tailings Remedial Action Program (UMTRAP) at various mine tailing sites in Colorado and Wyoming. The log interpretation model has now been completed, and a patent on the system has been issued. The tool design will be released to the National Technical Information Service, and is available for anyone to build and use; the software is also available.