Research on minimum detectable activity (MDA) of underwater gamma spectrometer for radioactivity measurement in the marine environment

• Published in: Applied radiation and isotopes 2020-01, Vol.155, p.108917-108917, Article 108917
• Main Authors: Zhang, Yingying, Wu, Bingwei, Liu, Dongyan, Lv, Hongmin, Feng, Xiandong
• Format: Article
• Language: English
• Subjects: Acquisition time; Background count; Detection efficiency; In-situ marine radioactivity measurement; Minimum detection activity (MDA); Underwater gamma spectrometer
• ISSN: 0969-8043; 1872-9800
• DOI: 10.1016/j.apradiso.2019.108917

To improve the capability of underwater gamma spectrometer to quantify radiation levels slightly above the background radiation in the seawater, the minimum detection activity (MDA) and factors including the background count, detection efficiency and acquisition time were studied using Monte Carlo simulation and field experiments. The simulation results show that the crystal type selected in the spectrometer and its volume, enclosure materials of the spectrometer and its thickness all affect the marine detection efficiency in in-situ measurement, and thus determine MDA of the underwater gamma spectrometer. The acquisition time and the placement depth of the spectrometer in the seawater also affect the MDA in the in-situ measurement. Some research data and suggestions on design and use of underwater gamma spectrometer were presented, which are of guiding significance for the in-situ radioactivity measurement in the marine environment. •The background gamma spectra and counting rates measured at different depths are presented.•The detection performance of underwater gamma spectrometer for different enclosure and crystal are compared.•MDA of underwater gamma spectrometer for different acquisition time are provided.•Some suggestions on development and application of underwater gamma spectrometer are put forward.