Sample preparation for the determination of radiocalcium by accelerator mass spectrometry |
| |
Authors: | P Sharma R Middleton D Fink J Klein |
| |
Institution: | Tandem Accelerator Laboratory, Department of Physics, University of Pennsylvania, Philadelphia, PA 19104 U.S.A. |
| |
Abstract: | An accelerator mass spectrometric (AMS) technique has been developed for determining 41Ca/40Ca ratios at terrestrial levels of 10?16?10?14. Calcium is extracted as calcium oxide from bone and rock samples. The calcium oxide is converted into calcium metal and subsequently into calcium hydride in a two-step reduction process. From these calcium hydride samples 5–10 μA of a negative-ion beam of CaH?3 is produced. A new gas-ionization detector and a high-resolution velocity detector allow discrimination against 41K and the stable isotopes of Ca, resulting in background levels of less than 6 × 10?16. Hence it is possible (for the first time without pre-enrichment) to study the distribution of 41Ca in the terrestrial environment. The AMS method for 41Ca determination is applicable to samples of less than 1 g. |
| |
Keywords: | |
本文献已被 ScienceDirect 等数据库收录! |