A 3 LAYER CIRCULAR SCINTILLATOR HODOSCOPE

The rotationally symmetric kinematics of hadronic reactions around the beam direction call for a detector system with an appropriate symmetr y. A hodoscope has been invented which optimally meets such conditions . A combination of both contrarotating and straight scintillator eleme nts form a three layer circular hodoscope. The overlap of individual c ounters defines pixels with a structure reminiscent of a sunflower pat tern. Thus, a rather large, granulated and flat detector arrangement h as been achieved economically. Such hodoscopes are in operation for me asurements at LEAR/CERN and CELSIUS/Uppsala. A third enlarged version is presently being tested and will be used in the Time Of Flight spect rometer (TOF) at COSY/Julich. The performance of individual detector e lements and of the complete system was investigated with various parti cle beams and cosmic rays. Comparisons with Monte Carlo calculations c onfirm the operation of the detector.