A New capability for 41Ca analysis using CaF 3 - at the Xi'an-AMS

The analysis of ⁴¹Ca can be quantified by measuring the ratio ⁴¹Ca/⁴⁰Ca. At present, ratios of ⁴¹Ca/⁴⁰Ca ≤ 10^âˆ'¹¹ can only be measured by accelerator mass spectrometry (AMS). The sensitivity is mainly limited by the interference of the isobar ⁴¹K. With compact AMS (≤1 MV), abundance sensitivities of 10^âˆ'¹¹ to 10^âˆ'¹² have been demonstrated, but this may necessitate the measurement of ³⁹K to correct for the ⁴¹K background. With a 3 MV AMS, the dE/dx method can still be used to partially separate ⁴¹Ca from ⁴¹K. In this work, a new capability for ⁴¹Ca analysis has been tested at the Xi'an-AMS. Ca⁴⁺ was chosen to achieve a balanced performance between ⁴¹Ca/⁴¹K separation and transmission efficiency. A ⁴¹Ca/⁴⁰Ca background level of near 10^âˆ'¹³ was achieved without the need for ³⁹K correction. This new analytical capability at our facility was then applied to ⁴¹Ca tracer samples from our studies on the "White Jade" land snail shells, in which ⁴¹Ca was used as a tracer for studying the absorption rate of calcium.