Preliminary study of 10Be/7Be in rainwater from Xi'an by Accelerator Mass Spectrometry

TL;DR

This study develops a method for measuring 7Be and 10Be in rainwater using Accelerator Mass Spectrometry at Xian, enabling routine, high-accuracy atmospheric tracer analysis.

Contribution

It introduces a new sample preparation and measurement procedure for simultaneous 7Be and 10Be analysis in rainwater samples at Xian-AMS.

Findings

The 10Be/7Be ratio in rainwater is approximately 1.3.

The method allows high-precision, routine analysis of rainwater samples.

Both isotopes can be measured in a single sample.

Abstract

The 10Be/7Be ratio is a sensitive tracer for the study of atmospheric transport, particularly with regard to stratosphere-troposphere exchange. Measurements with high accuracy and efficiency are crucial to 7Be and 10Be tracer studies. This article describes sample preparation procedures and analytical benchmarks for 7Be and 10Be measurements at the Xian Accelerator Mass Spectrometry (Xian-AMS) laboratory for the study of rainwater samples. We describe a sample preparation procedure to fabricate beryllium oxide (BeO) AMS targets that includes co-precipitation, anion exchange column separation and purification. We then provide details for the AMS measurement of 7Be and 10Be following the sequence BeO- -> Be2+ -> Be4+ in the Xian- AMS. The 10Be/7Be ratio of rainwater collected in Xian is shown to be about 1.3 at the time of rainfall. The virtue of the method described here is that both 7Be and 10Be are measured in the same sample, and is suitable for routine analysis of large numbers of rainwater samples by AMS.