A twin axial ionization chamber for studies of multiple intermediate-mass-fragment production in 1 GeV proton-nucleus collisions

A twin axial ionization chamber consisting of 16 cm deep parts was constructed. Two anode signals arising from the same particle trace were simultaneously recorded by two Flash ADCs. The on-line data handling procedure allows the determination of energy, energy loss, range and nuclear charge of the fragments. The energy resolution was better than 1.5%. A charge resolution ΔZ/Z<2.5% was found for nuclear charges within the range 2≤Z≤18. Isotopic separation for Li, Be and B is based on the determination of the range and the energy of the fragments as well as on the ΔE-E method. The mass resolution for these elements was about 3%. The twin axial ionization chamber was employed as precise detector in an arrangement which warrants large geometric coverage. The data acquisition system allows the simultaneous measurements of inclusive data as well as correlations between intermediate mass fragments from multiple events. (orig.)