We propose a novel antenna-coupled superconducting bolometer which makes use of the thermal boundary resistance available at low temperatures. The radiation is collected by a planar self-complementary antenna and thermalized in a small thin film resistor. The resulting temperature rise is detected by a transition edge thermometer which can be (but need not be) a separate film. All components are deposited directly on a substrate so that arrays can be conveniently produced by conventional lithographic techniques. The active area of the bolometer is thermally decoupled by its small size and by the thermal resistance of the boundaries with the substrate and the antenna terminals. Design calculations based on a 2 times 2 (mu)m square film of a superconductor with Tc approx. 0.1 K give an NEP approx. 10(exp -18) WHz(exp -1/2), time constant approx. 10(exp -6) s and responsivities up to approx. 10(exp 9) V/W. These specifications meet the requirements for NASA's Space Infrared Telescope Facility and Sub-Millimeter Moderate Mission. Useful applications also exist at He-3 and He-4 temperatures. The calculated NEP scales as T(exp 5/2). Materials, architectures, and readout schemes will be discussed.
Astrophysical Processes and Structures in the Universe
- Pub Date:
- September 1990
- Design Analysis;
- Low Temperature;
- Temperature Dependence;
- Instrumentation and Photography