Synchrotron-based high-pressure research in materials science Page: 2 of 7
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DEVELOPMENT OF A TIME MEASUREMENT SYSTEM FOR USE WITHIN
INFORMATION BARRIERS
Philip A. Hypes , Jeffrey M. Audia, Michael C. Browne, Kiril lanakiev, Duncan
MacArthur, Jason Shergur
Los Alamos National Laboratory, Group N-1, Los Alamos, New Mexico USA
Abstract:
We report on the development of a subsystem that, when used with an Attribute
Measurement System (AMS), can determine the current date without batteries,
continuous electrical connection, or user input. The device will allow the system to
determine the current date from the decay of a small radioactive source without
complication of the information barrier, system authentication, or security. This
subsystem may be used when an AMS needs to compare a calculated age with a
reference date independently and without external input. The requirements, design, and
other aspects of the time measurement subsystem will be discussed.
Background
Attribute measurement systems are designed to provide verification that classified items
possess certain attributes without releasing any classified information to unauthorized
personnel [1], [2]. The attributes often considered include Special Nuclear Material
(SNM) mass, isotopics or enrichment, and in the case of Plutonium items, the date of
chemical separation. Although there are well-established gamma-ray spectroscopy
techniques that can be used to determine the duration of time that has elapsed since
separation, it is not possible to determine the date of separation without having
knowledge of the measurement date. Establishing a measurement date is nontrivial
because allowing the user to enter the current date violates one of the primary
principles of information barrier design. Ideally, the user input should be minimized to
the greatest extent possible, preferably to as little as an on/off switch, a button to initiate
background measurements, a button to initiate calibration measurements, and a button
to initiate a measurement.
Computer-based methods could be used to monitor the current date, but they would
complicate the tasks of system authentication and certification. In other words, having a
computer in the system complicates the inspectibility and certification processes, thus
making it difficult to build confidence that there is no additional functionality embedded
in the computer. Additionally, computer-based methods require a battery to provide
power while the system is in storage. Storage periods may last for months, and the
inclusion of a battery violates the principles of information barrier design. [3]
The principles of information barrier design also preclude connecting the system to
another computer or network during startup. This means we cannot design the system
to obtain the current date from GPS or other data networks.1
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Synchrotron-based high-pressure research in materials science, article, Date Unknown; [Los Alamos, New Mexico]. (https://digital.library.unt.edu/ark:/67531/metadc934551/m1/2/: accessed April 25, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.