The first four years of the AMS-facility DREAMS: Status and developments for more accurate radionuclide data

DREAMS, the DREsden AMS-facility, is performing routine accelerator mass spectrometry of Be-10, Al-26, Cl-36, Ca-41, and I-129 for a wide range of applications. All DREAMS -data is normalised directly to primary standards or traceable to those via cross-calibration of secondary standards. Recent technical developments such as a low-memory ion source for Cl-36 and 1291 and sophisticated tuning strategies for I-129 led to improved-accuracy data. Tests of ion source output have been performed with different metal binders, sample-to-binder mixing ratios, and compaction pressures in order to find optimal parameters. The highest and most stable outputs have been obtained for Be-10, Al-26, and Ca-41 for the following binders and mixing ratios (by weight): BeO:Nb, 1:4; Al2O3:Ag, 1 :1; CaF2:Ag, 1:4. Higher beam currents generally result in reduced statistical uncertainty. Cross-contamination and long-term memory seem to be underestimated problems asking for further tests and improvements such as the development of low-level in-house-standards. (C) 2016 Elsevier B.V. All rights reserved.