Development of an array of calorimetric low-temperature detectors for heavy ion physics

Calorimetric low-temperature detectors have been investigated for several applications in heavy ion physics within the last 15 years. The detectors used consist of sapphire absorbers of 2×3×0.33 mm3 and superconducting aluminum transition edge sensors operated at T≈1.5 K. To fully exploit the potential of such detectors for heavy ion physics, a detector array is developed. For this purpose, a specially adapted 4He bath cryostat with a base temperature of 1.2 K, which allows an active detector area of 30×80 mm2, was constructed. As different detectors have different transition temperatures, each detector pixel has to be adjusted to its specific working point and temperature stabilized individually. First performance tests with a prototype array of two pixels have shown that the present concept can be used successfully also for larger arrays. In particular, the temperature stabilization of additional pixels does not affect the energy resolution. No cross talk between pixels was observed.