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Schwellenbach, David D.

Publications and source records attributed to Schwellenbach, David D..

12 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2018

Nevada National Security Site Site-Directed Research and Development Report (FY 2018 Annual Report)

This report compiles multiple articles describing activities developed and performed under the Site-Directed Research and Development Program for the benefit the Nation during Fiscal Year 2018. Sustained investment and ongoing core innovation are the keys to successful research and development programs. These elements drive the Site-Directed Research and Development (SDRD) Program and provide solutions to some of the most challenging problems our nation and our allies face. Our Nevada enterprise, consisting of both our management and operating entity and our NNSA field office, is aggressively investing in SDRD and injecting innovation through strategic partnerships. Our partnerships with universities, industry, and our sister institutions within the National Nuclear Security Administration (NNSA) build upon our core capabilities and allow us to create innovative solutions to support our mission requirements. In 2018, we raised the investment level of SDRD for only the second time in the history of the program. Nearly at our congressionally authorized limit, SDRD has substantial resources to successfully address numerous issues. Investment is only one part of the equation; innovation is generated through collaborations that bring discovery and provide the “technical differentiation” and the return on investment we seek. This report demonstrates an enduring theme of how partnerships help us drive the best outcomes and provide the maximum impact possible, while using our resources efficiently.

36 MATERIALS SCIENCE↗
DOE OSTI2015

Muon Tracking to Detect Special Nuclear Materials

Previous experiments have proven that high-Z materials can be located in shielded configurations and that nuclear assemblies can be imaged and identified inside of shipping containers using vertical trajectory cosmic-ray muons with two-sided imaging. These experiments have further demonstrated that nuclear assemblies can be identified by detecting fission products in coincidence with tracked muons. By developing these technologies, advanced sensors can be designed for a variety of warhead monitoring and detection applications. The focus of this project is to develop tomographic-mode imaging using near-horizontal trajectory muons for weapons and spent fuel applications. This will allow passive imaging in-situ without the need to relocate the objects.

cosmic ray muons, muon tracking, SNM, spent fuel↗
DOE OSTI2015

X-Ray Radar Imaging Technique Using a 2 Mev Linear Electron Accelerator

X-ray radar imaging, patented in 2013 by James R. Wood, combines standard radar techniques with the penetration power of x-rays to image scenes. Our project strives to demonstrate the technique using a 2 MeV linear electron accelerator (linac) to generate the S-band–modulated x-ray signals. X-ray detectors such as photodiodes and scintillators are used to detect the signals in backscatter and transmission detection schemes. The S-band microstructure is imposed on the variable-width electron pulse, and this modulation carries over to the bremsstrahlung x-rays after the electron beam is incident upon a copper-tungsten alloy target. Using phase/distance calculations and a low-jitter timing system, we expect to detect different object distances by comparing the measured phase differences. The experimental setup, which meets strict jitter requirements, and preliminary experimental results are presented.

43 PARTICLE ACCELERATORS↗
DOE OSTI2014

Detection of Petawatt Laser-Induced Muon Source for Rapid High-Z Material Detection

A proof-of-concept investigation of a rapid detection system for shielded high-Z material using a petawatt laser-based muon source is presented. Unlike cosmic-ray muons, a laser-induced muon beam has unique characteristics that can be exploited for use in a rapid detection system. These characteristics include: (1) a near-point source of muons, (2) well-characterized muon energies, and (3) directionality of the beam. A detector system is being developed that combines multiple muon detection technologies to characterize an active muon source. This detection system and the associated data acquisition and analysis techniques are designed to search for deflections of the muon beam as it passes through high-Z materials. Additionally, the ability of the system to differentiate muons from the expected secondary particles, such as high-energy gammas and electrons, is being explored. The detector system’s ability to differentiate muons from other particles, show muon angular distribution, and measured muon flux will be discussed.

scintillation detector, petawatt laser-based muon ↗
DOE OSTI2014

Imaging Shielded Configurations Using Near-Horizontal and Near-Vertical Trajectory Cosmic-Ray Muons

This work will describe the proof-of-concept research applying muon tomography technologies based on drift tube systems to create images using near–horizontal trajectory muons. To date, the majority of imaging studies using cosmic-ray muons have used near–vertical trajectory muons. This work compares imaging results using near–vertical trajectory muons with results using near–horizontal trajectory muons. The muon flux is much lower for the near–horizontal trajectory muons, so requiring longer imaging times, but the average muon energy is higher, so the horizontal results are expected to better differentiate high-Z materials. The muon tracking system is easily configurable and can be oriented to capture near–vertical trajectory or near– horizontal trajectory cosmic-ray muons. The software can track each muon passing through the system, and generate 3-D images of the scene. The experimental design and preliminary results will be presented, including the comparisons of detection efficiency, image resolution, and integration times.

muon, passive, imaging, tomography, cosmic↗