Realistic and immersive simulations of land, sea, and sky are requisite to the military use of visual simulation for mission planning. Until recently, the simulation of natural environments has been limited first of all by the pixel resolution of visual displays. Visual simulation of those natural environments has also been limited by the scarcity of detailed and accurate physical descriptions of them. Our aim has been to change all that. To this end, many of us have labored in adjacent fields of psych- ogy, engineering, human factors, and computer science. Our efforts in these areas were occasioned by a single question: how distantly can fast-jet pilots discern the aspect angle of an opposing aircraft, in visual simulation? This question needs some ela- ration: it concerns fast jets, because those simulations involve the representation of high speeds over wide swaths of landscape. It concerns pilots, since they begin their careers with above-average acuity of vision, as a population. And it concerns aspect angle, which is as much as to say that the three-dimensional orientation of an opposing aircraft relative to one’s own, as revealed by motion and solid form. v vi Preface The single question is by no means simple. It demands a criterion for eye-limiting resolution in simulation. That notion is a central one to our study, though much abused in general discussion. The question at hand, as it was posed in the 1990s, has been accompanied by others.

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This manual describes the use of version 3.2 of the PC/FRAM plutonium isotopic analysis software developed in the Safeguards Science and Technology Group, NE-5, Nonproliferation and International Security Division Los Alamos National Laboratory. The software analyzes the gamma ray spectrum from plutonium-bearing items and determines the isotopic distribution of the plutonium 241Am content and concentration of other isotopes in the item. The software can also determine the isotopic distribution of uranium isotopes in items containing only uranium. The body of this manual descnies the generic version of the code. Special facility-specific enhancements, if they apply, will be described in the appendices. The information in this manual applies equally well to version 3.3, which has been licensed to ORTEC. The software can analyze data that is stored in a file on disk. It understands several storage formats including Canberra's S1OO format, ORTEC'S chn' and SPC' formats, and several ASCII text formats. The software can also control data acquisition using an MCA and then store the results in a file on disk for later analysis or analyze the spectrum directly after the acquisition. The software currently only supports the control of ORTEC MCB'S. Support for Canbema's Genie-2000 Spectroscopy Systems will be added in the future. Support for reading and writing CAM files will also be forthcoming. A versatile parameter fde database structure governs all facets of the data analysis. User editing of the parameter sets allows great flexibility in handling data with different isotopic distributions, interfering isotopes, and different acquisition parameters such as energy calibration, and detector type. This manual is intended for the system supervisor or the local user who is to be the resident expert. Excerpts from this manual may also be appropriate for the system operator who will routinely use the instrument.