A new setup for the underground study of capture reactions

For the study of astrophysically relevant capture reactions in the underground laboratory LUNA a new setup of high sensitivity has been implemented. The setup includes a windowless gas target, a 4? BGO summing crystal, and beam calorimeters. The setup has been recently used to measure the d(p,?)3He cross-section for the first time within its solar Gamow peak, i.e. down to 2.5keV c.m. energy. The features of the optimized setup are described. © 2002 Elsevier Science B.V. All rights reserved.