Liquid hydrogen chamber with hydrogen recondensation by helium

The design of an installation with liquid hydrogen target for experiments with pion beams, conducted using the BIS-2 spark spectrometer, is described. The main elements of the device art the target, the system for supplying the gaseous hydrogen or deuterium for condensation, the system of automatic supply of liquid helium for hydrogen condensation, the unit for liquid helium level measurement and maintenance of the pressure in the Dewar flask and the pillar for commutation and parameter control. The explosion hazard is decreased in the described device by decreasing the hydrogen content upto the target working volume. Heat flux to the target is decreased using the additional cooling by cold helium vapours and also by criogenic line length decrease placing the target directly on the Dewar flask neck. The weight of cold parts and the time of the target working volume filling with liquid hydrogen are decreased and hydrogen freezing on condensation surface is eliminated by using heat-exchanger-condenser with forced flow