Engineering topics

Aalseth, Craig E

Publications and source records attributed to Aalseth, Craig E.

4 records

DOE OSTI2012

A shallow underground laboratory for low-background radiation measurements and materials development

Pacific Northwest National Laboratory recently commissioned a new shallow underground laboratory, located at a depth of approximately 30 meters-water-equivalent. This new addition to the small class of radiation measurement laboratories located at modest underground depths houses the latest generation of custom-made, high-efficiency, low-background gamma-ray spectrometers and gas proportional counters. This paper describes the unique capabilities present in the shallow underground laboratory; these include large-scale ultra-pure materials production and a suite of radiation detection systems. Reported data characterize the degree of background reduction achieved through a combination of underground location, graded shielding, and rejection of cosmic-ray events. We conclude by presenting measurement targets and future opportunities.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2011

CASCADES: An Ultra-Low-Background Germanium Crystal Array at Pacific Northwest National Laboratory

State-of-the-art treaty verification techniques, environmental surveillance, and physics experiments require increased sensitivity for detecting and quantifying radionuclides of interest. This can be accomplished with new detector designs that establish high detection efficiency and reduced instrument backgrounds. Current research is producing an intrinsic germanium (HPGe) array designed for high detection efficiency, ultra-low-background performance, and sensitive {gamma}--{gamma} coincidence detection. The system design is optimized to accommodate filter paper samples, e.g. samples collected by the Radionuclide Aerosol Sampler/Analyzer. The system will provide high sensitivity for weak collections on atmospheric filter samples (e.g.<10{sup 5} fissions) as well as offering the potential to gather additional information from higher activity filters using gamma cascade coincidence detection. The first of two HPGe crystal arrays in ultra-low-background vacuum cryostats has been assembled, with the second in progress. Traditional methods for constructing ultra-low-background detectors were followed, including use of materials known to be low in radioactive contaminants, use of ultra-pure reagents, and clean room assembly. The cryostat is constructed mainly from copper electroformed into near-final geometry at Pacific Northwest National Laboratory. Details of the detector assembly and initial background and spectroscopic measurement results are presented; also a description of the custom analysis package used by this project is given.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗

DOE OSTI2010

Majorana DUSEL R&D Final Report

This report summarizes the work performed at PNNL under the project Majorana Neutrinoless Double Beta Decay DUSEL R&D over the period of FY07-FY09.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2010

Digital Data Acquisition Graphical User Interface

Traditional radioxenon measurements have been done by ground based fixed systems, however in recent years there has been an increased need for systems capable of quick deployment or even complete mobility. Using the Pixie-4 data acquisition (DAQ) system can help reduce the electronics footprint of both current systems, like the radioxenon Radionuclide Laboratory 16 (RL-16) and the Swedish Automatic Unit for Noble Gas Acquisition (SAUNA), as well as future systems. Pacific Northwest National Laboratory (PNNL) has developed a Linux based Nyx graphical user interface (GUI) for Pixie-4 cards. The Nyx software can be installed on various Linux platforms and is written in C++. This software offers a rich user interface for configuring and operating the Pixie4 card and PNNL designed high voltage (HV) cards. Nyx allows one to quickly get a nuclear detector operational by maintaining the core diagnostic features built into the Pixie-4 cards. First, Nyx maintains the multitude of adjustable parameters accessible in the Pixie-4 cards, which allows one to customize settings to take full advantage of a particular detector. Nyx also maintains an oscilloscope feature which is extremely useful to optimize settings and to verify proper detector behavior and is often the first feature used in Nyx during detector setup. Finally, Nyx allows the user to collect data in several formats including full pulse shapes to basic histograms. Overall, it is the corner stone for the transition of beta-gamma systems to a state-of-the-art digitizing DAQ.

45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEF↗