Resolving multiple particles in a highly segmented silicon array

The design, construction, and performance of a new highly segmented charged particle detector array, FIRST, are described. This forward angle annular array (2∘⩽θlab⩽28∘) has been developed to study peripheral and mid-central heavy-ion collisions at intermediate energies (E/A≈50MeV). FIRST consists of three individual telescopes that each utilize ion-passivated silicon detectors in either a Si(IP)-Si(IP)-CsI(Tl) stack or a Si(IP)-CsI(Tl) stack. This array provides elemental identification for 1⩽Z⩽50 with isotopic identification of lighter elements, Z⩽13, over a wide dynamic range in energy. The high segmentation of each silicon detector provides good angular resolution in a compact geometry and allows deconvolution of multiple particles incident on a single telescope. The performance of the array in a commissioning experiment Zn64+Zn64,Bi209 at E/A=45MeV is shown.