Matrix readout for superconducting tunnel junction arrays
Publication date: 16 August 2000
Authors: Martin, D., et al.
Journal: SPIE Proceedings - Optical and IR Telescope Instrumentation and Detectors, Masanori Iye; Alan F. Moorwood; Eds.
Volume: 4008
Page: 328-336
Year: 2000
Copyright: SPIE
We report on the design and testing of a new readout scheme for Superconducting Tunnel Junction (STJ) arrays. By grouping the electrodes in rows and columns, this method drastically reduces the number of connections and electronic circuits reruired for reading out a large format array of pixelated detectors. It is a generic scheme in that it could be applied to different kinds of detector arrays. Using charge sensitive amplifiers with junction field-effect transistors (JFETs) we verify that the energy resolution degrades primarily due to capacitance increase at the amplifier's input node. However, since each detector is read-out by two independent circuits, these two outputs can be combined to increase the signal-tonoise level. The measurements reported here were carried out on an array of 6x6 junctions. All junctions were biased but only 2 rows and 2 columns read-out. We compare the results to measurements carried out on a similar 6x6 array fabricated from the same trilayer but with individual pixel read-out. The measurements show that stable biasing of STJs is possible with the new configuration and that the measured optical spectral line resolutions are consistent with our theoretical predictions.
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