Case studies of target properties in nuclear spectroscopy

A review of in-beam electron-gamma-ray coincidence measurements in nuclear spectroscopy particularly influenced by target properties is outlined. To illustrate such an influence, aspects of the recoil ion catcher method for the study of short lived nuclear isomers performed at the Orsay MP-tandem accelerator, are reported. This method is operated with a pulsed heavy-ion beam bombarding a thin self-supported target but avoiding to hit the catcher foil. The required characteristics of the targets and recoil ion stopper foils needed for these measurements are analyzed in detail for a few typical experimental arrangements. (orig.)