Am-Be Replacement with Tunable Neutron Spectra

241Am-Be(α,n) radiochemical neutron sources are used for geophysical well logging serving groundwater, mining, geotechnical, environmental and research users—as well as the major Oil/Gas industries. There is an urgent need to prevent intentional or accidental diversion and/or use as a radiological dispersal device. It is difficult to track/safeguard these materials with ~9,000 active sources for domestic oil/gas and ~4,500 sources for non-oil/gas geophysical sectors. The primary obstacle cited for 241Am-Be replacement is a change to the source effects the neutron emission spectrum and properties—requiring recalibration, tooling redesign and data reinterpretation. Phase II research has shown that the 2.5MeV D-D neutron energy exhibits excellent sensitivity to formation porosity and tooling re-design that takes advantage of the end-generated neutrons can effectively replicate the Near/Far formation response for compensated neutron logging (CNL) in limestone, dolomite and sandstone with suitable counting statistics. Neutron emission is at the generator end allowing unrestricted placement of near and far detectors to tailor the geophysical formation response.Starfire has partnered with Mt. Sopris Instruments to integrate our downhole neutron generator with an optimized set of near and far detectors to yield a compensated neutron logging tool that will mimic the Am-Be formation response. This is possible because neutrons in the 1-4MeV energy range are most responsible for the actual porosity measurement from the Am-Be reaction and the 2.5MeV D-D fusion emission is right in the sweet spot for optimization. Adjusting the near/far detector spacing, volume, pressurization, moderation and shielding results in an electronic CNL tool that is free from radiochemical sources with Phase IIB funding. The tool can be extended to PGNAA and meet an urgent need for the underserved non-oil/gas market.Commercial Applications and Other BenefitsThe technology has immediate application for radiochemical replacement in the underserved non-oil/gas geophysical water, mining and environmental well logging. Many customers cannot use Am-Be sources due to regulatory restrictions and threat of contamination. The Phase IIB technology would alleviate this gap and pain point for end uses. Partnering with Mt. Sopris for integration with industry-standard QL40 small-bore tooling and WellCAD software will be a boon for a wide customer base.