A time projection chamber for the three-dimensional reconstruction of two-proton radioactivity events

Two-proton radioactivity was observed in 2002 in the decay of (45)Fe. However, the experiments performed at that time did not allow the observation of the two protons directly. We present here a new setup based on the principle of a time-projection chamber that enabled us for the first time to identify directly the two protons. The new setup permits the observation and reconstruction in three dimensions of the traces of the protons and to determine thus their individual energies and their relative angle. We will discuss the setup in all necessary details and describe its performances in the context of two-proton radioactivity and beta- delayed two-proton emission studies. (C) 2009 Elsevier B.V. All rights reserved.