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Comparison of beta (LSC) and gamma (HPGe) spectrometric methods for lead-210 in chronological study

Mikalauskienė R., Mažeika J., Petrošius R., Szwarczewski P.

Geochronometria

2018

Vol. 45, no. 1

34--43

The sediments of two lakes located in the Baltic Uplands, the western part of the East European Plain (East Lithuania and North East Poland), were studied. Activity concentration of 210Pb was determined using two nuclear analytical techniques: determination of 210Pb in equilibrium with its beta emitting daughter 210Bi using liquid scintillation counter (LSC), and direct determination of 210Pb (and other radionuclides) by low-background gamma-ray spectrometer with a well type HPGe detector. For the 210Pb determination by LSC the methodology of lead separation based on the anion exchange resin in Cl– form (Eichrom) was used. Several steps of radiochemical procedures and respective parameters were investigated additionally. The optimized procedures for LSC method were used for case study with two lake cores. The activity concentration of 210Pb in lake sediment samples based on both nuclear analytical techniques (LSC and HPGe) were compared. 210Pb dating of cores was performed according to Constant Rate of 210Pb Supply (CRS) model with some modifications. Both techniques in the range of uncertainties gave similar results. From two considered lakes, the more eutrophic one exhibited higher sediment mass accumulation rate (MAR) values.

Determination of radioactivity in air filters by alpha and gamma spectrometry

Bem H., Bem E. M., Krzemińska M., Ostrowska M.

Nukleonika

2002

Vol. 47, nr 2

87-91

Combination of alpha and gamma spectrometry for air filters measurement allows a simple determination of all short-lived 222Rn and 220Rn daughters as well as cosmogenic 7Be and anthropogenic 137Cs in the air. Solid radionuclides in the atmosphere, attached to aerosol particles, were collected on filters of High Volume Air Sampler. After the desired collection period, the activity of deposited radionuclides was measured by ă-spectrometry for 7Be, 212Pb, 212Bi, 214Pb, 214Bi and by á-spectrometry for 212Po, 214Po and 218Po. Spectrometric methods do not require additional sample preparation and allow one to find aerosol activity by a simple filter measurement. A special measurement and calculation procedure was applied in the case of radionuclides from the uranium and thorium series. A technique of liquid scintillation counting (LSC) was used to determine the activity of the long-lived radon daughters 210Pb, 210Bi, 210Po after leaching into HCl solution and a two-step pre-concentration. Simultaneous determination of 210Pb and 210Bi enables one to find aerosol residence times.