Progress in fabrication of microcalorimeter arrays: X-ray absorbers and high-density stripline wiring

We report on advances in the fabrication technology of an array of microcalorimeters, to be used in future X-ray spectroscopic space missions. An optimization study was done to form high packing factor, mushroom-shaped, Bi absorbers by evaporation and sputter deposition techniques. The electrical, mechanical and thermal properties of the absorbers were characterized. We show the feasibility of wiring a 250 μm pitch, 32×32 pixel array with low-inductance striplines. A design for a prototype array has been made and fabrication is in progress.