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A high-resolution soft x-ray spectrometer is described and discussed.

Research involving noise-analysis of gamma-ray transition-edge sensor (TES) microcalorimeters is described and discussed.

High resolution Nb-A1-A10x-A1-Nb tunel junction extreme ultra-violet detectors were developed.

Superconducting Nb-Al-AlOx-Al-Nb tunnel junctions (STJ) were fabricated as high-resolution, high-count rate photon detectors using a modified photolithographic trilayer process. The developed STJ detectors have an energy resolution between 1.7 and 8.9 electronvolts full width at half maximum for photon energies between 0.05 and 1 kiloelectronvolt at count rates of up to 10,000 counts.

Superconducting tunnel junctions coupled to superconducting absorbers are proposed for high-efficiency high-resolution, x-ray spectrometry applications. Niobium x-ray absorbing layers coupled to aluminum layers that function as quasiparticle traps were analyzed. A 100 superconducting quantum interference device array amplifier was used to measure a large area tunnel junction's current pulses.

A new process was used in developing Ag/Al2O3/Al superconducting tunnel junctions on Si substrates. The junctions were then used to analyze a superconducting Al film's proximity effect on a normal metal trapping layer. The devices also permit the use of a single junction for hot-electron diffusion constant measurement as well as enhance the design and creation of tunnel junctions on high-Z, ultra-pure superconducting crystal surfaces.

Niobium thin films coupled to aluminum layers that serve as quasiparticle traps in an Nb/A1/A12O3/A1/Nb tunnel junction X-ray detector are configured as low-energy X-ray spectrometers. Although the device is only moderately successful as an X-ray detector, it can nevertheless be used as the basis for larger, more efficient superconducting absorbers. Results indicate the feasibility of using a large range of energy as a diagnostic technique for superconducting tunnel junction x-ray detectors.

Experiments are performed to determine the feasibility of using superconducting tunnel junctions with niobium X-ray absorbing layers coupled to aluminum layers serving as quasiparticle traps and as high-resolution, high-efficiency X-ray spectrometers. Results indicate that junctions with high-quality barriers whose sides have 200 nm-thick trapping layers have the best energy resolution among potential X-ray spectrometers.

The characteristics of a high-efficiency X-ray spectrometer fabricated using niobium absorbers coupled to two aluminum layers on either side of the tunneling barrier were studied. The device was subjected to x-ray induced current pulses and its dynamic response was measured using feedback electronics. Results show that the detector exhibits nonlinear response to X-ray excitation.

A prototype dark matter detector consisting of a superconducting tunnel junction array on the surface of a sapphire crystal is presented. Non-thermal photon signals are generated when dark matter particles interact with the crystal sapphire. These signals are then detected by the aluminum tunnel junctions. The viability of the proposed detector was evaluated using 6-MeV alpha particles. Results show that the detector is capable of giving high energy resolution sufficient for application in experiments to detect particle dark matter.

Research is presented concerning the development of a novel design for a solid-state microrefrigerator. The design is based on normal-insulator-superconducting tunnel junctions which can cool to almost 100mK.

Reports on the use of superconducting tunnel junctions coupled to superconducting absorbers, as high-resolution, high-efficiency X-ray spectrometers. Testing of devices with niobium X-ray absorbing layers; Measurement of current pulses.