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Displaying 526 - 550 of 615

Performance of 32-channel Time-Division SQUID Multiplexer for Cryogenic Detector Arrays

June 1, 2003
Author(s)
Joern Beyer, Piet DeKorte, Carl D. Reintsema, Sae Woo Nam, Gene C. Hilton, Leila R. Vale, Kent D. Irwin
Multiplexed readout is a practical requirement for the successful deployment of large-scale cryogenic detector arrays in applications ranging from x-ray microanalysis to sub-millimeter astronomy. We report on the development of a time-division SQUID

Superconducting Multiplexers for Transition-Edge Sensors

June 1, 2003
Author(s)
Kent D. Irwin, James A. Beall, Joern Beyer, Steven Deiker, W.Bertrand (Randy) Doriese, S. L. Ferreira, Gene C. Hilton, Sae Woo Nam, Carl D. Reintsema, Joel Ullom, Leila R. Vale
Superconducting multiplexers make it possible to build arrays of thousands of low-temperature bolometers and microcalorimeters based on superconducting transition-edge sensors with a manageable number of readout channels. Our first generation SQUID

Tungsten Transition-Edge Sensors for IR/Optical/UV Photon Counting

June 1, 2003
Author(s)
Aaron J. Miller, Sae Woo Nam, John M. Martinis, Alexander V. Sergienko
Tungsten transition-edge sensors have been demonstrated to have impressive photon-counting capabilities. Of particular interest is the expected impact to the applications of low-flux astronomy and photonic quantum information. The combination of high

An AC Josephson Source for Johnson Noise Thermometry

April 1, 2003
Author(s)
Samuel Benz, John M. Martinis, Paul Dresselhaus, Sae Woo Nam
We have adapted the Josephson arbitrary waveform synthesizer to create a quantized voltage noise source suitable for calibrating the cross-correlation electronics of a Johnson noise thermometer system. The requirements of long term stability and low

Johnson Noise Thermometry Measurements Using a Quantized Voltage Noise Source for Calibration

April 1, 2003
Author(s)
Sae Woo Nam, Samuel Benz, Paul Dresselhaus, Weston L. Tew, David R. White, John M. Martinis
We describe a new approach to Johnson Noise Thermometry(JNT) that takes advantage of recent advances in Josephson voltage standards and digital signal processing techniques. Currently, high-precision thermometry using Johnson noise is limited by the non

Decoherence of a Superconducting Qubit due to Bias Noise

March 25, 2003
Author(s)
John M. Martinis, Sae Woo Nam, Joe Aumentado, Kristine Lang, C Urbina
We calculate for the current-biased Josephson junction the decoherence of the qubit state from noise and dissipation. The effect of dissipation can be entirely accounted for through a noise model of the current bias that appropriately includes the effect

Time-Division SQUID Multiplexers for Transition-Edge Sensors

January 14, 2003
Author(s)
Kent D. Irwin, James A. Beall, Joern Beyer, Steven Deiker, W.Bertrand (Randy) Doriese, S. L. Ferreira, Gene C. Hilton, Sae Woo Nam, Carl D. Reintsema, Joel Ullom, Leila R. Vale
Microcalorimeters and bolometers based on superconducting transition-edge sensors (TES) are important tools for the detection of photons from millimeter waves through gamma rays, and for applications ranging from materials analysis to astronomy. There is a

A ratiometric method for Johnson noise thermometry using a quantized voltage noise source

January 1, 2003
Author(s)
Sae Woo Nam, Samuel Benz, John M. Martinis, Paul Dresselhaus, Weston L. Tew, David R. White
Johnson Noise Thermometry (JNT) involves the measurement of the statistical variance of a fluctuating voltage across a resistor in thermal equilibrium. Modern digital techniques make it now possible to perform many functions required for JNT in highly

A Well Dressed Microscope: Practical Experience with Microcalorimeter and Silicon Drift Detector Systems

December 31, 2002
Author(s)
John A. Small, Dale Newbury, John Henry J. Scott, L. King, Sae Woo Nam, Kent D. Irwin, Steven Deiker, Shaul Barkan, Jan Iwanczyk
NIST, Gaithersburg has recently installed a first generation silicon drift detector (SDD) from Photon Imaging and the NIST Boulder microcalorimeter energy dispersive x-ray spectrometer (υcal-EDS) on a JEOL 840 SEM, as shown in Fig. 1. [1,2] The instrument

The Development of Microcalorimeter EDS Arrays

November 1, 2002
Author(s)
Kent D. Irwin, James A. Beall, Steven Deiker, Gene C. Hilton, L. King, Sae Woo Nam, Dale Newbury, Carl D. Reintsema, John A. Small, Leila R. Vale
High-energy-resolution cryogenic microcalorimeters are a powerful new tool for x-ray microanalysis. With demonstrated energy resolution 20 times better than with conventional semiconductor EDS, microcalorimeters are useful in applications such as nanoscale

Rabi Oscillations in a Large Josephson Junction Qubit

September 9, 2002
Author(s)
John M. Martinis, Sae Woo Nam, Joe Aumentado, C Urbina
We have designed and operated a circuit based on a large-area current-biased Josephson junction whose two lower energy quantum levels could be used to implement a solid-state qubit. The circuit allows measurement of the qubit states with a fidelity of 85%