Abstract

We have designed and tested an ultra high responsivity liquid helium-3 refrigerated bolometer for use in low-background applications. The bolometer consists of a single germanium crystal 1/4 x 1/4 x 1/4 mm with contacts at diagonally opposite corners. A short length of gold wire (0.7 mil diameter) is bonded to the contact which is soldered to 5 mm lengths of 1/2 mil stainless steel wire. The other end of each of the stainless steel wires is bonded to a metallized diamond heatsink for the 0.3°K bath. Secondary heatsinking of incoming electrical leads is with indium buried copper transformer wire. The result is a high sensitivity yet fast (10 ms time constant) bolometer suitable for use in low background environments with P_B < 250 pw.

© 1980 Optical Society of America