Groups from all over the world use the DESY test beam. Prototypes of particle detectors of only one square millimetre and others weighing several hundreds of kilograms; components which will become the heart of a detector and others designed for the outer layers of future detectors. All these will be put to the acid test at DESY’s oldest accelerator.

The DESY test beam offers a wide range of possibilities to the users. Under the fire of electrons and positrons of one to six Giga electron volts, the users may test properties like response behaviour and accuracy of their detector types – this is decisive for the future function in the experiment. The beam for the three measuring stations is not decoupled directly from the accelerator. It is generated by introducing a hair-thin wire into the DESY beam. This creates photons which, through another target, are converted into electron-positron pairs. A magnet behind the target gives the test beam user the possibility to select the energy of the electrons
individually. Moreover, this does not disturb the filling of PETRA III and, therefore, the photon science user run. In the test beam, there is a pixel telescope and a superconducting magnet, both available to the experimenters. The accelerator that operates since 1964 is a coveted facility for technology development.