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RESEARCH PRODUCT

Precision Measurements of Atomic Masses Using Highly Charged Ions and Atomic Clusters

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description

A high precision Penning trap will be connected to the beam of highly charged ions from the electron beam ion source CRYSIS at the Manne Siegbahn Institute for Physics (MSI) in Stockholm. The first series of experiments aim at accurate mass measurements by exploiting the increase of the cyclotron frequency with the charge state of the trapped ion. Using charged states of about 50 it should be possible to achieve relative mass accuracies for mass doublets better than 10-9. For this high accuracy a Penning trap with low imperfections is needed, as well as a sophisticated beam handling and retardation system for controlled injection of the ions into the trap. In order to minimize the effect of residual trap imperfections the ion motion has to be cooled. In addition the use of mass doublets will contribute to the highest accuracies. We also intend to investigate singly charged cluster ions which offer a new method of achieving mass doublets. So for example a 28Si3 -cluster has the same mass number 84 as a 12C7 cluster. Using such singly charged clusters, produced in an external source, we hope to achieve a relative mass accuracy of about 10-8 for 28Si/ 12C. This measurement is part of an attempt to search for a new atomic kilogram standard. Using fully stripped ions the accuracy should be improved by at least another factor of ten.