A -- THE USE OF SUPERCONDUCTOR-INSULATOR-NORMAL (SIN) TUNNEL JUNCTIONS IN

Notice Date

June 18, 2001

Contracting Office

Department of Commerce, National Institute of Standards and Technology (NIST), Acquisition and Logistics Division, 100 Bureau Drive, Building 301, Room B129, Mail Stop 3571, Gaithersburg, MD, 20899-3571

ZIP Code

20899-3571

Description

Researchers at the National Institute of Standards and Technology (NIST) are working on the following technologies. We have developed a SQUID multiplexer circuit to read out large arrays of superconducting detectors. This circuit allows many superconducting transition-edge sensors to be sampled with one output channel, without any degradation in noise performance. In this circuit, each TES element is read out by a single first-stage SQUID amplifier. The bias lines of each N-element column of SQUIDs is connected in series. The total signal across the entire column is monitored by a 100-SQUID series array. The bias is applied to the first-stage SQUIDs through N+1 address resistors which are connected to each column. However, the bias is only applied to one of the first-stage SQUIDs in each column, leaving the others in their superconducting, or 'off' state. Since the SQUIDs outside of the addressed row are superconducting, they contribute no signal or noise to the readout, and dissipate no power. For an N x N array, as the address bias is switched from row to row, the vector of SQUID outputs sequentially provides a measurement of the current flowing through the transition-edge thermometers in each row of the array. In order to increase the linearity and dynamic range, each time a first-stage SQUID is sampled, a feedback signal is applied to the common flux modulation coil. With the one dimension of multiplexing, the number of wires will scale as the number of elements on one side of the array instead of the number of microcalorimeters. For further information, contact: National Institute of Standards and Technology, Office of Technology Partnerships, 100 Bureau Drive, Stop 2200, Gaithersburg, MD, 20899; Telecopy: 301-869-2751. This is not an announcement of a contract action or a grant.

Web Link

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Record

Loren Data Corp. 20010620/SPMSC025.HTM (D-169 SN50P2A1)