Secondary Beam Targetry Developments

Two recently developed target manipulators have increased the versatility of remote multitargeting in the production of secondary particles from within the Argonne Zero Gradient Synchrotron (ZGS). The Mark II manipulator is constructed in modular form to facilitate assembly in one of four arm-swing configurations. This allows new coverage patterns for the three to four manipulator combinations that can multitarget on a single synchrotron pulse. It also provides for quick, accurate target changes by replacement of a complete presurveyed arm and target assembly. A current pulsed coil, reacting with the guide field, thrusts the target of the Mark IV manipulator upwards from the bottom of the beam chamber. The Mark IV compact design permits close targeting positions between manipulators. The manipulator provides distinct target movements in each of the three coordinate axes (X, Y, and Z), as well as rotation in the XZ plane. This enhances automatic target positioning control. An exact replica of the 32-in x 70-in meson targeting area has been used for positional presurveys of meson targets and for the calibration of their positional readout systems. This use has greatly reduced radiation exposure to personnel and contributed substantially towards a 50% reduction in the ZGS maintenance time.