Cosmic-ray induced background reduction by means of an anticoincidence shield

The cosmic-ray induced background of a spectrometer is reduced by means of an active veto shielding. Two such spectrometers have been developed: one equipped with a well type Ge detector and the other with a 50% relative efficiency coaxial Ge detector. In both cases, the active veto shielding consists of plastic scintillating plates and an anticoincidence electronic system. Although these devices have lower performances than those placed in an underground laboratory, their advantage is that they can be used in a normal laboratory environment. (author)