MACY: A Multi-wire Avalanche Counter at Yale

MACY (a Multi-wire Avalanche Counter at Yale) has recently been built in the WNSL at Yale. It is a position-sensitive proportional detector that will be used at the focal plane of the gas-filled recoil spectrometer SASSYER to detect heavy ions produced in nuclear reactions. This detector comprises of an anode plane, a cathode plane, and two position-sensitive wire planes that are kept on ground potential. Its primary purpose is to distinguish recoiling nuclei of interest from scattered beam particles. It provides information on energy loss and it also serves as an efficient start detector for a time-of-flight measurement. In addition, MACY measures the X and Y position of the transmitted particle. Design and first experimental results are presented. This work has been supported by the DOE under grant numbers DE-FG02-91ER-40609 and DE-FG02-88ER-40417