AMS Ground Truth Measurements: Calibration and Test Lines

Wasiolek, P.¹ 

[1]National Security Technologies, LLC. (NSTec), Mercury, NV (United States)

关键词: AERIAL MONITORING;    AIRCRAFT;    HELICOPTERS;    GROUND TRUTH MEASUREMENTS;    CALIBRATION;    SURFACE CONTAMINATION;    SCINTILLATION COUNTERS;    GAMMA SPECTROSCOPY;    RADIATION ACCIDENTS;    REACTOR ACCIDENTS;    ALTITUDE;    MAPS;    VELOCITY;    GROUND LEVEL Aerial Measuring System;    AMS;    ground truth;   

DOI  :  10.2172/1134255
RP-ID  :  DOE/NV/25946--1942
PID  :  OSTI ID: 1134255
Others  :  TRN: US1600002

美国|英语

来源: SciTech Connect

【 摘 要 】

Airborne gamma spectrometry is one of the primary techniques used to define the extent of ground contamination after a radiological incident. Its usefulness was demonstrated extensively during the response to the Fukushima nuclear power plant (NPP) accident in March-May 2011. To map ground contamination a set of scintillation detectors is mounted on an airborne platform (airplane or helicopter) and flown over contaminated areas. The acquisition system collects spectral information together with the aircraft position and altitude every second. To provide useful information to decision makers, the count rate data expressed in counts per second (cps) needs to be converted to the terrestrial component of the exposure rate 1 m above ground, or surface activity of isotopes of concern. This is done using conversion coefficients derived from calibration flights. During a large scale radiological event, multiple flights may be necessary and may require use of assets from different agencies. However, as the production of a single, consistent map product depicting the ground contamination is the primary goal, it is critical to establish very early into the event a common calibration line. Such a line should be flown periodically in order to normalize data collected from different aerial acquisition systems and potentially flown at different flight altitudes and speeds. In order to verify and validate individual aerial systems, the calibration line needs to be characterized in terms of ground truth measurements. This is especially important if the contamination is due to short-lived radionuclides. The process of establishing such a line, as well as necessary ground truth measurements, is described in this document.