Calibration of detectors of relativistic charged particles and gamma quanta by means of the system for production of quasimonochromatic annihilation photons

A system for producing precision beams of positrons and quasi-monochromatic annihilation photons having different parameters is described. The system is developed on the base of a linear accelerator and contains four converter taro.ets, transport analyzing systems, and a collimator. Primary beam monitors are ionization chambers which permit measuring the currents of up to 1g-15A. The system provides sufficiently reliable oroduction of positron (electron) beams with an intensity of 1-100 1/s at energies of 8-70 MeV and energy spread of 1-2 %. Some examples of employing precision beams to calibrate different detectors are cited. On a 60 MeV positron beam the detection efficiency and response functions of the Cherenkov counter have been measured, depending on the place at which the beam hits the detector. A curve of X-ray film blackening obtained when exposing it to a positron beam at an energy of 60 MeV is presented