Real Photons

Precision measurements of bremsstrahlung in the reaction pp pp gamma were thought for a long time to allow an access to the semi-off-shell properties of the proton-proton T-matrix, thus supplementing our knowledge on the strong nucleon-nucleon interaction. Very recently this motivation was debated. With the time-of-flight spectrometer TOF  at COSY in Juelich it is possible to measure the real photon spectrum via a missing mass analysis. Recent experiments have demonstrated that this principle works successfully below the pion threshold. Now a new series of more precise experiments with extracted polarized proton beam is prepeared. Physicists from Rossendorf participate in the TOF collaboration mainly togehter with colleagues from Technical University Dresden. Due to the technical services and infrastructure it was possible to build up the big barrel segment (length 3 meter, diameter 3 meter) in Rossendorf and to install it after test measurements at the COSY beam in Juelich.