The development of radioactive ion beam facilities has opened the opportunity to perform direct reactions with unstable beams in inverse kinematics. This requires light targets of suitable density (0.1-1 mg/cm2) to achieve a luminosity sufficient for nuclear spectroscopy. A prototype for a cryogenic 3,4He target was developed at Legnaro National Laboratories, reaching the required helium density operating at a temperature around 10 K. The design was chosen for its compatibility with the future GRIT-AGATA set-up and SPES exotic beams. It also offers good transparency to y rays. The results of tests with an a source and of a commissioning with a proton beam are reported.