Centro Nacional de Aceleradores

MiCaDaS Accelerator

The Micadas system (Mini Carbon Dating System) was installed at CNA in 2012, and since then routine 14C measurements have been performed for the Radiocarbon Dating Service at CNA.

It is based on the Accelerator Mass Spectrometry (AMS) technique, but using a lower terminal voltage of just 200 kV, five times lower than the voltage used in the analogue AMS system at CNA, SARA. Micadas is a 14C dedicated system, and no other isotope is measured in it.
The system was initially designed by the AMS group at the Ion Beam Physics Laboratory at the ETH (Federal Institute of Technology) in Zürich, Switzerland. At present, the system is commercialised by the company Ionplus.

Its configuration is similar to other AMS systems, but wholly optimized for the transport and identification of the carbon isotopes, thus allowing some simplifications in the system. The graphite samples, previously prepared in the lab, are introduced in a Caesium sputtering ion source to produce the beam, and this is analysed with the usual AMS filters. At the 200 kV terminal the stripping process breaks the molecules and ions change charge state, q=1+ being selected at the high energy side, where the final analysis of the beam components is performed. Finally, 14C is quantified in an ionization chamber, meanwhile stable isotopes are quantified in the corresponding Faraday cups.
The Micadas system is a comprehensive concept, including a software package for sample preparation control, creation of sample batches for measurement, and data analysis. Besides, it is optimized to work together with the AGE graphitization system, developed by the same group and also installed at CNA.

To sum it up, the Micadas system is a compact, 14C dedicated facility, with a small size of only 2.6x3.4 m2, simplified in comparison with other multielemental AMS systems, and capable to obtain comparable results.