Lump correction and identification in the combined thermal/epithermal neutron (CTEN) method

The authors present a model for self shielding in lumps of fissile material in active-neutron assays. The model combines the formula for self-attenuation of gamma-ray in lumpy sources with the multi-group analysis techniques used in neutron transport calculations. Models for thin foils and for spheres are examined in terms of error multiplication in determining lump corrections and the basic accuracy of the model

A Time Purified Separated Antiproton Beam At The AGS

Physic

Livestock waste management for energy recovery in Brazil: a life cycle assessment approach.

Abstract: Livestock farming has exerted intense environmental pressure on our planet. The high emissions to the environment and the high demands of resources for the production process have encouraged the search for decarbonization and circularity in the livestock sector. In this context, the objective of this study was to evaluate and compare the environmental performance of two different uses for biogas generated in the anaerobic digestion of animal waste, either for electricity generation or biomethane. For this purpose, a life cycle assessment approach was applied to evaluate the potential of anaerobic digestion as a management technology for three different livestock wastes, related to beef cattle, dairy, and sheep in the Brazilian animal production context. The results suggest that the treatment scenarios focusing on biomethane generation were able to mitigate the highest percentage of damages (77 to 108%) in the global warming category when compared to the scenarios without the use of anaerobic digestion (3.00·102 to 3.71·103 kgCO2 eq) or in the perspective of electricity generation (mitigation of 74 to 96%). In terms of freshwater eutrophication, the generation of electricity (− 2.17·10−2 to 2.31·10−3 kg P eq) is more favorable than the purification of biogas to biomethane (− 1.73·10−2 to 2.44·10−3 kg P eq), due to the loss of methane in the upgrading process. In terms of terrestrial ecotoxicity, all scenarios are very similar, with negative values (− 1.19·101 to − 7.17·102 kg 1,4-DCB) due to the benefit of nutrient recovery, especially nitrogen, associated with the use of digestate as fertilizer, which was one of the critical points in all scenarios. Based on these results, it is evident that proper management of all stages of the treatment life cycle is the key to decarbonization and circularity in livestock waste management. The biogas use does not present different effects on the environmental performance of the scenarios studied, demonstrating that the purpose should be chosen according to the needs of each plant or management system

A POLARIMETER FOR PROTONS BETWEEN 100 AND 800 MeV

A carbon polarimeter has been built and used for protons with energies between 100 and 800 MeV. The polarimeter accepts scatters in the carbon analyzer up to 30~ab, with negligible instrumental asymmetries. Drift chambers 60 cm square were used with a system for resolving the left-right ambiguity inherent in drift chambers. A hardware system for rejecting small angle scatters is described. The polarimeter is routinely used to measure spin transfer parameters with a typical precision of ±0.03 in about eight hours of low-duty LAMPF beam

Advances in nuclear instrumentation for safeguards

This paper describes detectors, instrumentation, and analytical methods under development to address the above issues. The authors will describe work underway on room-temperature semiconductors including attempts to model the response of these detectors to improve spectrum analysis procedures and detector design. Computerized tomography is used in many medical and industrial applications; they are developing both gamma-ray and neutron tomography for improved measurements of waste and direct-use materials. Modern electronics and scintillation detectors should permit the development of fast neutron coincidence detectors with dramatically improved signal-to-noise ratios. For active measurements, they are studying several improved neutron sources, including a high-fluence, plasma-based, d-t generator. New analysis tools from information theory may permit one to better combine data from different measurement systems. This paper attempts to briefly describe a range of new sensors, electronics, and data analysis methods under study at Los Alamos and other laboratories to promote discussion of promising technology that they may bring to bear on these important global issues

Photofission-Based, Nuclear Material Detection: Technology Demonstration

The Idaho National Engineering and Environmental Laboratory (INEEL), the Los Alamos National Laboratory (LANL), and the Advanced Research and Applications Corporation (ARACOR) [Sunnyvale, California] performed a photonuclear technology demonstration for shielded nuclear material detection during August 21–22, 2002, at the LANL TA-18 facility. The demonstration used the Pulsed Photonuclear Assessment Technique (PPAT) that focused on the application of a photofission-based, nuclear material detection method as a viable complement to the ARACOR Eagle inspection platform. The Eagle is a mobile and fully operational truck and cargo inspection system that uses a 6-MeV electron accelerator to perform real-time radiography. This imaging is performed using an approved “radiation-safe” or “cabinet safe” operation relative to the operators, inspectors, and any stowaways within the inspected vehicles. While the PPAT has been primarily developed for active interrogation, its neutron detection system also maintains a complete and effective passive detection capability

Chiral perturbation theory calculation for pn -> dpipi at threshold

We investigate the reaction pn -> dpipi in the framework of Chiral Perturbation Theory. For the first time a complete calculation of the leading order contributions is presented. We identify various diagrams that are of equal importance as compared to those recognized in earlier works. The diagrams at leading order behave as expected by the power counting. Also for the first time the nucleon-nucleon interaction in the initial, intermediate and final state is included consistently and found to be very important. This study provides a theoretical basis for a controlled evaluation of the non-resonant contributions in two-pion production reactions in nucleon-nucleon collisions.Comment: 24 pages, 3 figures, 3 table