b'FeatureAirborne radiometrics over Maralinga - call for a new survey Figure 2. Caesium 137 Thomson Aviation 2018 survey with calculated activity concentrations in kBq/m2. Ground zero sites are indicated with small circles and triangles. The square marks the test range (data and image processing by Pavel Jurza).Systems, surveys and processingThe data collection and processing of the \x1eve surveys could be seen to fall into two distinct categories. The \x1erst survey by EG&G is a Military type. The EG&G Redar IV was built solely to measure man-made radioisotopes whilst Modern systems were designed to discover uranium ore for the nuclear reactors and are observed to be more sophisticated.EG&G/ Energy Measurements, Inc.The \x1erst survey was conducted in 1987 by EG&G/Energy Measurements Inc (EG&G), who were contracted by the United States Department of Energy on behalf of the Australian Government. Cosmic radiation, the naturally occurring radiation from potassium, uranium and thorium, the Compton continuum, variations due to aircraft radiation, humidity and aircraft height were treated as noise to be eliminated. This was Figure 3. Caesium 137 image from World Geoscience Corporations 1992 surveyachieved by dividing the Signal Window containing the gamma over the test range. Ground zero sites are named and indicated with circles andphotopeak of the desired element by an adjacent, higher triangles as in Table 5. The activity concentrations in Becquerels per square metre areenergy Background Window (Table 6).indicated in the colour bar. The northeast-southeast striations are due to sand dunes.The Signal Window 38 keV-74 keV for the americium photopeak at 59.5 keV was lower in the energy spectrum than windows Table 5.Details of the nuclear explosion eventstypically employed by all but the most recent of Modern (atombombs) at Maralinga between spectrometers. EG&G also conducted a ground survey to 1956-1957 with series, dates and yields. calibrate the airborne data. They employed a high purity Symbol Series Ground zero site Date Yield (kt)Bu\x1falo One Tree 27/9/1956 15Table 6.The Signal Windows EG&G used to capture Bu\x1falo Marcoo 4/10/1956 2 isotopes and the Background Windows by Bu\x1falo Kite 11/10/1956 3 which they were divided (Tipton et al 1988).Bu\x1falo Breakaway 22/10/1956 10 IsotopeSignal Window keV Background Window keVAntler Tadje 14/9/1957 1 241Am. 38-74 74-102Antler Biak 25/9/1957 6 137Cs 590-734 734-854Antler Taranaki 9/10/1957 27 152Eu, 60Co974-1550 1550-3026APRIL 2024PREVIEW 49'