Compton suppression gamma-spectroscopy in the analysis of radium and lead isotopes in ocean sediments

Abstract

Compton suppression gamma-spectroscopy provides an efficient method for measuring the concentration of 226Ra, 228Ra, and 210pb in ocean sediments. The background reduction realized from the suppressed mode of operation provides an "active shield" to allow for the low-level counting required for these measurements. We have used the method to study the possible accumulation of radium from produced waters in sediments from Gulf of Mexico sites of varied distances from drill platforms. In addition, 210pb levels were determined to evaluate the use of our spectrometer for this purpose. Baseline undisturbed concentrations have been obtained from the study of subsurface core material which predates drilling activities. Correlations of radium isotope concentrations with iron and barium provide information concerning the possible relationships between radium levels and drilling activity (excess barium) and natural variations in sediment texture (iron).

Techniques for Measuring Uranium-series Nuclides: 1992-2002

“…Compton suppression gamma spectrometry has been applied for 228 Ra determination (James et al 1998), but is particularly applicable for high-activity measurements where background is created by Compton scattering of gamma radiation originating from the sample itself. For low-activity measurements the Compton suppressor may act as a guard against cosmic radiation, although surrounding a Ge detector with the Compton suppressor may actually increase background from natural radioactivity present in the components of the suppressor.…”

Destructive and Nondestructive Determination of <sup>226</sup>Ra and <sup>228</sup>Ra in Drinking Water by Gamma Spectrometry

“…The sensitivity of radium determination by gamma spectrometry depends on several sample-related factors, such as sample volume [8], preconcentration on Mn-based medium [9] [10], coprecipitation with BaSO 4 [11] [12], coprecipitation with PbSO 4 [6] or nondestructive analysis [5]. On the instrumental side, the sensitivity depends on the efficiency of the Ge spectrometer, extent and purity of shielding materials, use of active cosmic-muon rejection [13], Compton suppression [14], as well as counting time.…”