Abstract:
Efforts are continually being made in remediation surveys to reduce the
time and manpower required to perform work while maintaining the ability to
detect low levels of contamination. To this end, organizations are utilizing
portable instrumentation in conjunction with global positioning systems (GPS).
This combination of technologies allows a surveyor to scan an area and record
the count rate information along with the GPS coordinates. The data can then be
mapped and cleanup efforts focused on areas that exceed set action levels. This
study examined the effect of scanning speed on detector efficiency for four
detectors and whether the scanning efficiency could be predicted. To
accomplish this, a track was designed to allow a source to pass under the
detector at speeds up to 1 m s⁻¹. To simulate the use of a GPS, a data-logger
was used to collect the data for each run. Decreases in scanning efficiency were
seen not only as the result of scanning speed but also as a function of signal
processing. Results indicate that the scanning efficiency could be predicted
using an equation that includes the static efficiency, detector diameter, the
scanning speed, and the response time.
