Measurement of the lifetime of heavy Lambda hypernuclei with the recoil shadow method and internal targets in the storage ring COSY-Julich

For the measurement of the lifetime of the A hyperon in very heavy hypernuc lei we have used proton projectiles for the production of strangeness and t he recoil shadow method in the circulating beam of COSY-Julich. This permit ted us to use a very thin ribbon target without loss in luminosity. The tar get fabrication and frameless mounting is described in detail. A special mo de of operating COSY was developed in order to bump the beam onto the targe t and to apply a supercycle. A description is given of the apparatus, tests , the calibration and the data analysis. As an example the p + Bi results a re presented and discussed. (C) 1999 Elsevier Science B.V. All rights reser ved.