First steps towards small arrays of Mo/Au microcalorimeters

We are developing small arrays of microcalorimeters based on transition edge sensors made with Mo/Au bilayers deposited on silicon nitride membranes and Au absorbers. The superconducting transition of the bilayers is adjusted to be around 130 mK with a transition width better than a millikelvin by use of the proximity e!ect between the Au and Mo "lms. We built a dilution refrigerator and wired it for 2 channel operation in order to study thermal coupling issues between thermometers within the array. The device fabrication procedure as well as preliminary results are presented. ( 2000 Elsevier Science B.V. All rights reserved.