A Liquid-Argon Ionization Detector for the Study of Double β Decay

A multisection liquid-argon ionization detector has been developed by the DBA collaboration to study double β decay of 100Mo. The experiment has been carried out in the Gran Sasso underground laboratory in Italy. The detector design and main characteristics are described. The limits on the 42Ar and 222Rn concentrations in liquid Ar are ≤4.3 · 10–21 g/g and ≤1.2 · 10–3 Bq/kg, respectively.