Internal targets at storage rings

Abstract

Internal targets play an important role in nuclear and high energy physics research. After many decades of development, these targets have become very common and highly complex devices. Different types of polarized and unpolarized targets, such as atomic beam, gaseous-, liquid- and solid-state targets, are used in various experiments at storage rings all over the world. The choice and usage of devices (both current and those in development) for internal experiments are strongly dependent on the many parameters of stored beams (e.g. dimensions, lifetime, cooling availability and polarization) and design parameters of the target (areal density, dimensions of the interaction point, target cooling, the gas load to the target chamber and time structure of the target). All these parameters are tightly coupled and must be considered together. The different internal targets are presented in this paper.