Manufacture and Testing of an Activation Foil Package for Use in AFIDS

摘要

This study used simulation and experiment to design and test foil packets for use in the Activation Foil Integrated Detection System (AFIDS). The initial plan to activate foil packets outside with the pulse reactor at White Sands Missile Range (WSMR) was not possible due to WSMR not having safety approval to take the reactor outside. As an alternative, the concept of using liquid nitrous oxide inside a reactor to simulate large volumes of air was investigated. Simulation using the Standardized Computer Analyses for Licensing Evaluation (SCALE) program was used to select ten foils to be included in the foil packet. The size was selected with a target activity of 25 Bq for each foil four days after the activation when located 500 meters from a five kiloton equivalent neutron weapon. We analyzed whether N2O could replicate large volumes of air in neutron transport experiments since one cubic centimeter of liquid N2O contains as many molecules as 1371 cubic centimeters of air. A neutron propagating through the liquid N2O should react like a neutron propagating through 1371 times as much air. Actual testing could not be completed at the Ohio State University Research Reactor due to hazardous levels of radiation in the facility during testing. The results of the simulation showed that pragmatic experimental factors inhibit use of the reactor in this way and an outside test is still required to provide the information Oak Ridge National Laboratory (ORNL) needs to validate the methodology used in Domestic Nuclear Event Attribution (DNEA).