Citation

Pöllänen R, Toivonen H, Peräjärvi K, Karhunen T, Ilander T, Lehtinen J, Rintala K, Katajainen T, Niemelä J, Juusela M. Appl. Radiat. Isot. 2009; 67(2): 340-344.

Affiliation

STUK-Radiation and Nuclear Safety Authority, P.O. Box 14, FI-00881, Finland.

Copyright

(Copyright © 2009, Elsevier Publishing)

DOI

10.1016/j.apradiso.2008.10.008

PMID

19046635

Abstract

Radiation surveillance equipment was mounted in a small unmanned aerial vehicle. The equipment consists of a commercial CsI detector for count rate measurement and a specially designed sampling unit for airborne radioactive particles. Field and flight tests were performed for the CsI detector in the area where (137)Cs fallout from the Chernobyl accident is 23-45kBqm(-2). A 3-GBq (137)Cs point source could be detected at the altitude of 50m using a flight speed of 70kmh(-1) and data acquisition interval of 1s. Respective response for (192)Ir point source is 1GBq. During the flight, the detector reacts fast to ambient external dose rate rise of 0.1muSvh(-1), which gives for the activity concentration of (131)I less than 1kBqm(-3). Operation of the sampler equipped with different type of filters was investigated using wind-tunnel experiments and field tests with the aid of radon progeny. Air flow rate through the sampler is 0.2-0.7m(3)h(-1) at a flight speed of 70kmh(-1) depending on the filter type in question. The tests showed that the sampler is able to collect airborne radioactive particles. Minimum detectable concentration for transuranium nuclides, such as (239)Pu, is of the order of 0.2Bqm(-3) or less when alpha spectrometry with no radiochemical sample processing is used for activity determination immediately after the flight. When a gamma-ray spectrometer is used, minimum detectable concentrations for several fission products such as (137)Cs and (131)I are of the order of 1Bqm(-3).

Language: en