Reference Samples Preparation of ~(41)Ca in AMS Measurement

In order to eliminate the isobaric interference of 41K in the AMS measurement, the sample has to be in form of CaH 2. CaH 2 is produced in a two-step reduction process. First,CaO is converted into calcium metal by vacuum distillation from a heated mixture of CaO and excessive Zr powder. Then the calcium metal is transferred to a second system and heated in the presence of hydrogen gas to form CaH 2. The conversion efficiency of Ca metal to CaH 2 is larger than 90%.