The GERDA experiment aims to search for the neutrinoless double beta-decay of
76Ge and possibly for other rare processes. The sensitivity of the first phase
is envisioned to be more than one order of magnitude better than in previous
neutrinoless double beta-decay experiments. This implies that materials with
ultra-low radioactive contamination need to be used for the construction of the
detector and its shielding. Therefore the requirements on material screening
include high-sensitivity low-background detection techniques and long
measurement times. In this article, an overview of material-screening
laboratories available to the GERDA collaboration is given, with emphasis on
the gamma-spectrometry. Additionally, results of an intercomparison of the
evaluation accuracy in these laboratories are presented.Comment: Featured in: Proceedings of the XIV International Baksan School
"Particles and Cosmology" Baksan Valley, Kabardino-Balkaria, Russia, April
16-21,2007. INR RAS, Moscow 2008. ISBN 978-5-94274-055-9, pp. 228-232; (5
pages, 0 figures
