The first two detectors, M1 and M2, are position-sensitive "matrix" devices (pictured at left) that form the hodoscope measuring the trajectory and energy loss of incident nuclei. The matrix detectors are octagonal in shape, 70 to 80 µm in thickness, and have 34 cm² active areas that are divided into 64 strips. Each of the strips on M1 and M2 is individually pulse-height analyzed with its own 12-bit ADC when an event occurs so that the trajectory of heavy ions traversing the system can be separated from the tracks of low energy H or He that might happen to hit one of these detectors at the same time. Detectors M1 and M2 are separated by 6 cm; the resulting rms angular resolution of the system is ~0.25 degrees, averaged over all angles