Development of a crystal surface stripping method for a downsized accelerator mass spectrometer

Abstract

Gas strippers have been a major obstacle to the downsizing of conventional accelerator mass spectrometry (AMS) systems. We investigated the application of a “crystal surface stripper method” to a downsized AMS system. Using a prototype system with a maximum acceleration voltage of 45 kV, we experimentally evaluated the charge-exchange and molecular-dissociation characteristics of carbon negative ions on potassium chloride, tin telluride, and gold surfaces. The results showed that the observed charge-state distributions were in good agreement with a resonant charge-transfer model. However, the dissociation efficiency of interfering molecules did not reach the required suppression level (10⁻¹²), even at 45 keV, indicating the need for further improvement. This study highlights the remaining challenges in realizing next-generation downsized AMS systems and establishes an important foundation for their future development.