Government of the United States of America, As Represented by the Secretary of Commerce

John M Martinis

Kent David Irwin

Gene Charles Hilton

David Anders Wollman

Walter M Gibson

Steve Castles

Robert Gregory Downing

Michael Nahum

Multi-layer transition-edge sensors (TES) having improved performance, a method for preparing them and methods of using them. Specifically, the improvement lies in providing normal metal strips along the edges of the superconducting and normal metal layers parallel to the current flow in the TES during operation. These strips (referred to as &ldquo;banks&rdquo;) provide for both improved detector performance and improved detector robustness against corrosion. This improvement is an important advance particularly for TES-based microcalorimeter detectors. The improved TESs also have many other applications based on the very precise thermometer function achieved by the TES.

Normal metal boundary conditions for multi-layer TES detectors

A system and method for using one or more localized weak-link structures, and damping on the electrical bias circuit, to improve the performance of superconducting transition-edge sensors (TES). The weak links generally consist of an area or areas having a reduction in cross-sectional geometry in an otherwise uniform bilayer TES applied to a substrate. The weak links control the dissipation of power in the sensor, making it quieter and making its electrical response smoother and less hysteretic. The TES response is also made smoother by implementing a damping circuit on the electrical output of the TES.

Superconducting transition-edge sensor with weak links

This invention provides a mechanical support for a two-pill Adiabatic Demagnetization Refrigerator (ADR). The support utilizes a suspension of the two pills from one side of the magnet bore only. In the two pill ADR, the thermal ground is at 4K, a guard pill positioned in the front of the bore cools to 1K and a base pill positioned in the back of the bore cools to 50-100 mk. A connector rod of the base pill traverses the guard pill, and connector rods to both the guard pill and base pill exit through the front aperture. A preferred embodiment of the two-pill support for the front loaded magnet bore utilizes planar support modules comprising three members connected by Kevlar strings. Each member is thermally connected either to one of the pills or to thermal ground. The ground member, the guard member and the base member of the support module are strung with Kevlar threads, such that the base member is suspended only from the guard member, and the guard member only from the ground member. These planar support modules can be aligned and assembled prior to use in an assembly jig. The final assembly of the two-pill support structure using planar support modules is easy and fast.

Mechanical support for a two pill adiabatic demagnetization refrigerator

Spectroscopic materials analysis wherein a sample under test is bombarded by electrons in a scanning electron microscope to produce an x-ray emission collected over a large solid angle by a polycapillary lens and focused onto the surface of a microcalorimeter detector. The x-ray lens is used to increase the effective collection area of the microcalorimeter detector used in an x-ray spectrometer. By increasing the collection angle, the time period for x-ray collection is reduced and the detector can be located farther from the x-ray source. The x-ray lens is effective over a broad energy range of x-rays, thus providing compatibility with spectroscopic analysis. The microcalorimeter can be calibrated to compensate for any variations in the transmission efficiency of the x-ray lens.

Microcalorimeter x-ray detectors with x-ray lens

This invention provides a method and apparatus for particle detection utilizing an Al/normal-metal bilayer transition-edge sensor (TES) coupled with a particle absorber. The TES is maintained in the transition region where its properties are extremely sensitive to temperature. In the detector, the energy of an absorbed particle is converted to heat by the absorber and the transition from the bilayer's superconducting to normal state is used to sense the temperature rise. The transition temperature, T.sub.c, of the bilayer can be reproducibly controlled as a function of the relative thicknesses and the total thickness of the superconducting and normal-metal layers. The range of available T.sub.c 's extends from below 50 mK to above 1 K, allowing the detector to be tailored to the application. For x-ray detection the preferred T.sub.c is about 50-150 mK. The width of the transition edge can be less than 0.1 mK, which allows very high detector sensitivity.

Superconducting transition-edge sensor

A detector of X-ray and the like in which very good resolution of energy can be obtained. The device is based on two basic components. The first is the x-ray absorber in which an x-ray interacts with a film and converts its energy into heat. Because the absorber is operated at cryogenic temperatures, approximately the range of 0.01 Kelvin to 1 Kelvin, its heat capacity is small and causes a measurable temperature rise. The second component of the invention is a base layer of normal metal which absorbs the heat generated by the x-ray. The third component of the invention is the method to detect the temperature rise. This thermometer is based on a normal metal-insulator-superconductor tunnel junction, where part of the base layer is the normal metal. When the tunnel junction is electrically biased at a voltage slightly below the gap voltage of the superconductor, the electrical current that flows through the junction is sensitively dependent on the temperature of the normal metal.

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Boulder, CO, United States of America

John M Martinis