The maximal area of superconducting tunneling junction x-ray detectors determined by the required signal-to-noise ratio
Abstract
The intrinsically high energy resolution of superconducting tunneling junctions (STJ) requires a low noise charge sensitive amplifier circuit. The noise sources of such a junction + amplifier circuit are discussed. The dominant noise sources are the series noise and the {1}/{f} flicker noise of the FET input stage, amplified by the large input capacitance of the STJ-detector. Means to reduce this capacitance are discussed. Reducing the preamplifier noise by a factor of two and the height of the potential barrier of the insulating layer by two orders of magnitude, by keeping the large conductance of the junction constant, would allow an increase in junction area by a factor of 15.
- Publication:
-
Nuclear Instruments and Methods in Physics Research A
- Pub Date:
- October 1987
- DOI:
- 10.1016/0168-9002(87)90112-4
- Bibcode:
- 1987NIMPA.260..430T