DNDO Report: Predicting Solar Modulation Potentials for Modeling Cosmic Background Radiation

Technical Report · Mon Aug 08 00:00:00 EDT 2016

DOI:https://doi.org/10.2172/1296694· OSTI ID:1296694

Behne, Patrick Alan ^[1]

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1. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

The modeling of the detectability of special nuclear material (SNM) at ports and border crossings requires accurate knowledge of the background radiation at those locations. Background radiation originates from two main sources, cosmic and terrestrial. Cosmic background is produced by high-energy galactic cosmic rays (GCR) entering the atmosphere and inducing a cascade of particles that eventually impact the earth’s surface. The solar modulation potential represents one of the primary inputs to modeling cosmic background radiation. Usosokin et al. formally define solar modulation potential as “the mean energy loss [per unit charge] of a cosmic ray particle inside the heliosphere…” Modulation potential, a function of elevation, location, and time, shares an inverse relationship with cosmic background radiation. As a result, radiation detector thresholds require adjustment to account for differing background levels, caused partly by differing solar modulations. Failure to do so can result in higher rates of false positives and failed detection of SNM for low and high levels of solar modulation potential, respectively. This study focuses on solar modulation’s time dependence, and seeks the best method to predict modulation for future dates using Python. To address the task of predicting future solar modulation, we utilize both non-linear least squares sinusoidal curve fitting and cubic spline interpolation. This material will be published in transactions of the ANS winter meeting of November, 2016.

• Research Organization: Los Alamos National Laboratory (LANL), Los Alamos, NM (United States)
• Sponsoring Organization: USDOE; U.S. Dept. of Homeland Security (DHS)
• DOE Contract Number: AC52-06NA25396
• OSTI ID: 1296694
• Report Number(s): LA-UR-16-26115; TRN: US1601769
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
98 NUCLEAR DISARMAMENT, SAFEGUARDS, AND PHYSICAL PROTECTION
FORECASTING
HELIOSPHERE
BACKGROUND RADIATION
MODULATION
COSMIC RADIATION
ENERGY LOSSES
LEAST SQUARE FIT
POTENTIALS
COMPUTERIZED SIMULATION
INTERPOLATION
RADIATION DETECTORS
CALIBRATION
NONLINEAR PROBLEMS
TIME DEPENDENCE
DETECTION
FISSILE MATERIALS
SPLINE FUNCTIONS
HARBORS
LEVELS