Abstract. Low-divergent quasi-stationary neutral beams are often applied in modern magnetic fusion devices as a diagnostic tool providing unique information about plasma parameters. One of most important requirements to these beams is sufficiently large current and energy of the particles, so that the beam can penetrate to the plasma core. Also the duration of the beams must be long enough, i.e. close to that of a plasma discharge, amounting to at least a few seconds for large fusion devices. In the Budker Institute, Novosibirsk, a series of diagnostic hydrogen (or helium) beams were developed which is capable of meeting these requirements for fusion devices of different types and scales. The maximum beam energy of the beams is upto 55 keV and an ion current is up to 5 A (for hydrogen). A pulse duration of the beams ranges from 0.1 ms up to 10 s. The low divergent beams (0.5°-0.7°) with initial radius of 3-5 cm can be geometrically focused at desired region within the plasma. The multiple second beam can be additionally modulated with a frequency variable up to 500 Hz. In the paper, the beam parameters obtained for different modifications of the ion source are presented.