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New measurements are presented from the LANL-NIST micorcalorimeter array for two standard plutonium sources. The results demonstrate substantially smaller error bars obtained from the spectral analysis program FRAM. Some areas of improvement to the analysis technique have been identified, indicating that the microcalorimeter results can be improved upon. These results support the viability of a device for performing real nuclear safeguards measurements in the near future. [ABSTRACT FROM AUTHOR]

We will present our work on the development of ultra-high-resolution detectors for alpha particle spectrometry. These detectors, based on superconducting transition-edge sensors, offer energy resolution that is five to ten times better than conventional silicon detectors. Using these microcalorimeter detectors, the isotopic composition of mixed-actinide samples can be determined rapidly without the need for actinide separation chemistry to isolate each element, or mass spectrometry to separate isotopic signatures that can not be resolved using traditional alpha spectrometry (e.g. Pu-239/Pu-240, or Pu-238/Am-241). This paper will cover the detector and measurement system, actinide source preparation, and the quantitative isotopic analysis of a number of forensics- and safeguards-relevant radioactive sources. [ABSTRACT FROM AUTHOR]

Microcalorimeters have been shown to yield unsurpassed energy resolution for alpha spectrometry, up to 1.06 keV FWHM at 5.3 MeV. These detectors use a superconducting transition-edge sensor (TES) to measure the temperature change in an absorber from energy deposited by an interacting alpha particle. Our system has four independent detectors mounted inside a liquid nitrogen/liquid helium cryostat. An adiabatic demagnetization refrigerator (ADR) cools the detector stage to its operating temperature of 80 mK. Temperature regulation with ∼15-μK peak-to-peak variation is achieved by PID control of the ADR. The detectors are voltage-biased, and the current signal is amplified by a commercial SQUID readout system and digitized for further analysis. This paper will discuss design and operation of our microcalorimeter alpha-particle spectrometer, and will show recent results. [ABSTRACT FROM AUTHOR]

This paper describes the design, development, testing and performance at Ball Aerospace of a long life, 4–6 K temperature space cryocooler. For temperatures to 4 K and below, Ball has developed a hybrid Stirling/ Joule-Thomson (J-T) cooler. The hybrid cooler has been verified in test to 3.5 K on a Ball program and a 6 K Development Model is in development on the NASA/JPL Advanced Cryocooler Technology Program (ACTDP). This paper will include the test status on the Stirling Precooler and the Thermal System Breadboard. The ACTDP cooler provides simultaneous cooling at 6 K (typically, for either doped Si detectors or as a sub-Kelvin precooler) and 18 K (typically, for optics or shielding) with cooling stages also available at 40 and 180 K (typically, for thermal shields or other components). The ACTDP cooler is under development for the NASA Terrestrial Planet Finder (TPF), Constellation X-Ray (Con-X), and other future missions. The 4–6 K cooler is highly leveraged off previous Ball space coolers including multiple life test and flight units. © 2006 American Institute of Physics [ABSTRACT FROM AUTHOR]