LRT2010 is the third workshop in the series on low radioactivity materials and techniques, which is the most fundamental part of rare-event physics detectors, such as for solar neutrinos, dark matter, double-beta decay, and long half-life phenomena. Topics include global surveys of low background facilities, detectors and shielding techniques, ultra-low background purification techniques, cleaning and contamination control, low background construction and fabrication, and background calculations and simulations.

The main purpose of the 2nd Topical Workshop on Low Radioactivity Techniques was to share the knowledge on techniques and developments aimed at ultra-low level backgrounds. Extremely low backgrounds are needed for searches looking for rare events such as dark matter or solar neutrinos. The articles gathered in this proceeding are unique since they provide technical details on low radioactivity techniques developments.

The work presented in this book is a major step towards understanding and eventually suppressing background in the direct search for dark matter particles scattering off germanium detectors. Although the flux of cosmic muons is reduced by many orders of magnitude in underground laboratories, the remaining energetic muons induce neutrons through various processes, neutrons that can potentially mimic a dark matter signal. This thesis describes the measurement of muon-induced neutrons over more than 3 years in the Modane underground laboratory. The data are complemented by a thorough modeling of the neutron signal using the GEANT4 simulation package, demonstrating the appropriateness of this tool to model these rare processes. As a result, a precise neutron production yield can be presented. Thus, future underground experiments will be able to reliably model the expected rate of muon-induced neutrons, making it possible to develop the necessary shielding concept to suppress this background component.

The determination of the properties of the neutrino is one of the most pursued goals of physics. The series of MEDEX Conferences, which started ten years ago, is devoted to the update of the experimental and theoretical information related to the nuclear double beta decay, which is the process that may, if observed, be the tool to answer the fundamental questions related to the neutrino mass scale. MEDEX is a unique forum for theoreticians and experimentalists active in the field.

This workshop examined the state-of-the-art of all techniques for measuring radioactivity at ultra-low activity levels as well as all aspects of the development of low-background detectors. Such detectors are needed to study physical processes that can only be observed when all sources of interfering background are reduced to a very low level. These techniques are essential to develop next generation detectors for neutrino research, solar neutrino physics, and neutrino astrophysics, as well as measurement of the double beta-decay process and the search for dark matter in the universe. Topics covered include experimental radio-purity requirements, methods for shielding detectors from cosmic rays and local radioactivity, methods for the measurement of impurities in bulk materials, in gases, and on surfaces, techniques for materials purification, and related subjects. The workshop marked the beginning of excavation for the new international facility for deep underground particle astrophysics (SNOLAB), located in Sudbury, Canada.