Quality Limitations of Hadron Beams

The parameters which characterize the quality of hadron beams in the different accelerators or storage rings most commonly used or in project are reviewed. Owing to the absence of natural damping mechanism, hadron beams require careful manipulations. Some of those are described, in particular the processes used to inject from one machine into another. Among the phenomena which have to be carefully controlled in order to reach the desired performance, special attention is given to space-charge and slow instabilities arising from non-linearities.