A multifunctional cryo-target for the external COSY experiments

Small liquid hydrogen/deuterium targets are routinely used in extracted-beam experiments at the proton synchrotron COSY/Jülich. The dimensions of a typical target cell are in the range of a few mm, with extremely thin window foils. A fast, only locally acting heating procedure for removing condensates from the cold foils was developed. Filling and operation with different liquefied gases is possible without breaking the vacuum. Higher luminosities for hydrogen targets can be reached by using CH4 rather than H2 liquids as qualitatively demonstrated for the pp →ppπ0 reaction.