Erlangen 2018 – scientific programme

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MS: Fachverband Massenspektrometrie

MS 5: Accelerator Mass Spectrometry 1

MS 5.2: Talk

Wednesday, March 7, 2018, 14:30–14:45, R 1.020

Beryllium-7 at DREAMS — •Georg Rugel¹, Silke Merchel¹, Andreas Scharf¹, Rebecca Querfeld², Georg Steinhauser², and Collin Tiessen^1,3 — ¹HZDR, Dresden, Germany — ²IRS Hannover, Germany — ³AEL AMS Laboratory, Canada

Half-lives of routine AMS nuclides range from thousands to millions of years. We measured short-lived ⁷Be (T_1/2 = 53.2 d) at the DREsden AMS-facility (DREAMS) [2] as low as 90 mBq, which can be challenging for rapid γ-counting. Simultaneous determination of ⁷Be and ¹⁰Be (T_1/2 = 1.387 Ma) via AMS is advantageous for improved understanding of production, transport, and deposition of atmospherically produced ^7,9,10Be [2].

Data was normalized to a ⁷Be sample produced via ⁷Li(p,n)⁷Be, measured by γ-counting and chemically processed to BeO (⁷Be/⁹Be ≈ 10⁻¹²). The isobar ⁷Li is completely eliminated by chemistry and the degrader foil technique (⁷Be⁴⁺, 10.2 MeV). The blank ratio of 5× 10⁻¹⁶ ⁷Be/⁹Be (0.8 mBq) and simple and fast chemistry allows for the measurement of rainwater samples, collected in Germany, as small as 10 ml corresponding to a few times 10⁻¹⁴ ⁷Be/⁹Be [3,4].

Thanks to D. Bemmerer (HZDR) and G. György (ATOMKI, Hungary) for help with the ⁷Be normalization material.

Ref.: [1] G. Rugel et al., NIMB 370 (2016) 94. [2] A.M. Smith et al., NIMB 294 (2013) 59. [3] R. Querfeld et al., JRNC 314 (2017)521. [4] C. Tiessen et al. JRNC (submitted).