Publikationsrepositorium - Helmholtz-Zentrum Dresden-Rossendorf

Since the DREAMS (Dresden Accelerator Mass Spectrometry) facility went operational in 2011, constant effort was put into enabling routine measurements of long-lived radionuclides as ¹⁰Be, ²⁶Al and ⁴¹Ca. For precise AMS-measurements of the volatile element Cl the key issue is the minimization of the long term memory effect [1]. For this purpose one of the two original HVE sources was mechanically modified, allowing the usage of bigger cathodes with individual target apertures. Additionally a more open geometry was used to improve the vacuum level. To evaluate this improvement in comparison to other up-to-date ion sources, a small interlaboratory comparison had been initiated.
The long-term memory effect in the Cs sputter ion sources of the AMS facilities VERA, ASTER and DREAMS had been investigated by running samples of natural ³⁵Cl/³⁷Cl-ratio and samples containing highly enriched ³⁵Cl (³⁵Cl/³⁷Cl > 500). Primary goals of the research are the time constants of the recovery from the contaminated sample ratio to the initial ratio of the sample and the level of the long-term memory effect in the sources.
[1] R. Finkel et al., NIMB 294 (2013) 121.