Preliminary results on double beta decay of 130Te with an array of twenty cryogenic detectors

Preliminary results on double beta decay of Te-130 obtained in the first run of an array of twenty cryogenic detectors are presented. The set-up is made with crystals of TeO2 of 340 grams each corresponding to the largest presently operating cryogenic mass. It was run under a heavy shield in the Gran Sasso Underground Laboratory at a depth of about 3500 m.w.e. By recording the pulses of each detector in anticoincidence with the others a 90% c.l. lower limit of 5.6 x 10(22) years has been obtained on the lifetime for neutrinoless double beta decay of Te-130 in a preliminary test run, corresponding to about one week of effective running time. No evidence is also found for double beta decay to the first excited 2(+) state of Xe-130 with a 90% c.l. lower limit of 1.7 x 10(22) years on that lifetime. Some consequences of the present results in the interpretation of geochemical experiments are discussed. (C) 1998 Elsevier Science B.V. All rights reserved.