1,725 Matching Results

Search Results

Advanced search parameters have been applied.

Process Monitor Analysis Victoreen Model 350

Description: Abstract: An analysis of the improved Model Number 350 Process Monitor was made so that it could be determined if this instrument would fulfill the need for gamma radiation detection instruments in the production buildings of Y-12. The results of these tests indicated the possibility of marked improvement in the monitor characteristics with minor redesigns. After these improvements have been made, this instrument will be a satisfactory monitor for this area.
Date: May 1, 1947
Creator: Harter, J. A. & Olson, E. L.
Partner: UNT Libraries Government Documents Department

Summary Report for the Radiation Detection for Nuclear Security Summer School 2012

Description: The Pacific Northwest National Laboratory (PNNL) hosted students from across the United States at the inaugural Radiation Detection for Nuclear Security Summer School from June 11 – 22, 2012. The summer school provided students with a unique understanding of nuclear security challenges faced in the field and exposed them to the technical foundations, analyses, and insight that will be required by future leaders in technology development and implementation. The course heavily emphasized laboratory and field demonstrations including direct measurements of special nuclear material. The first week of the summer school focused on the foundational knowledge required by technology practitioners; the second week focused on contemporary applications. Student evaluations and feedback from student advisors indicates that the summer school achieved its objectives of 1) exposing students to the range of nuclear security applications for which radiation detection is necessary, 2) articulating the relevance of student research into the broader context, and 3) exciting students about the possibility of future careers in nuclear security.
Date: August 22, 2012
Creator: Runkle, Robert C.; Baciak, James E. & Stave, Jean A.
Partner: UNT Libraries Government Documents Department

Algorithms Performance Investigation of a Generalized Spreader-Bar Detection System

Description: A “generic” gantry-crane-mounted spreader bar detector has been simulated in the Monte-Carlo radiation transport code MCNP [1]. This model is intended to represent the largest realistically feasible number of detector crystals in a single gantry-crane model intended to sit atop an InterModal Cargo Container (IMCC). Detectors were chosen from among large commonly-available sodium iodide (NaI) crystal scintillators and spaced as evenly as is thought possible with a detector apparatus attached to a gantry crane. Several scenarios were simulated with this model, based on a single IMCC being moved between a ship’s deck or cargo hold and the dock. During measurement, the gantry crane will carry that IMCC through the air and lower it onto a receiving vehicle (e.g. a chassis or a bomb cart). The case of an IMCC being moved through the air from an unknown radiological environment to the ground is somewhat complex; for this initial study a single location was picked at which to simulate background. An HEU source based on earlier validated models was used, and placed at varying depths in a wood cargo. Many statistical realizations of these scenarios are constructed from simulations of the component spectra, simulated to have high statistics. The resultant data are analyzed with several different algorithms. The simulated data were evaluated by each algorithm, with a threshold set to a statistical-only false alarm probability of 0.001 and the resultant Minimum Detectable Amounts were generated for each Cargo depth possible within the IMCC. Using GADRAS as an anomaly detector provided the greatest detection sensitivity, and it is expected that an algorithm similar to this will be of great use to the detection of highly shielded sources.
Date: October 1, 2010
Creator: Robinson, Sean M.; Ashbaker, Eric D.; Hensley, Walter K.; Schweppe, John E.; Sandness, Gerald A.; Erikson, Luke E. et al.
Partner: UNT Libraries Government Documents Department

Smart Surfaces: New Coatings & Paints with Radiation Detection Functionality

Description: Paints are being developed and tested that might ultimately be able to detect radiological agents in the environment by incorporating special pigments into an organic polymeric binder that can be applied as a paint or coatings. These paints detect radioactive sources and contaminants with inorganic or organic scintillation or thermo-luminescent pigments, which are selected based upon the radiation ({alpha}, {beta}, {gamma} or n) to be detected, and are shown in Figure 1.
Date: March 12, 2007
Creator: Farmer, J & Choi, J
Partner: UNT Libraries Government Documents Department

Status of the large-scale dark-matter axion search

Description: If axions constitute the dark matter of our galactic halo they can be detected by their conversion into monochromatic microwave photons in a high-Q microwave cavity permeated by a strong magnetic field. A large-scale experiment is under construction at LLNL to search for halo axions in the mass range 1.3 - 13 {mu}eV, where axions may constitute closure density of the universe. The search builds upon two pilot efforts at BNL and the University of Florida in the late 1980`s, and represents a large improvement in power sensitivity ({approximately}50) both due to the increase in magnetic volume (B{sup 2}V = 14 T{sup 2}m{sup 3}), and anticipated total noise temperature (T{sub n} {approximately}3K). This search will also mark the first use of multiple power-combined cavities to extend the mass range accessible by this technique. Data will be analyzed in two parallel streams. In the first, the resolution of the power spectrum will be sufficient to resolve the expected width of the overall axion line, {approximately}{bigcirc} (1kHz). In the second, the resolution will be {bigcirc}(O.01-1 Hz) to look for extremely narrow substructure reflecting the primordial phase-space of the axions during infall. This experiment will be the first to have the required sensitivity to detect axions, for plausible axion models.
Date: September 1, 1994
Creator: Van Bibber, K.; Hagmann, C.; Stoeffl, W.; Daw, E.; Rosenberg, L.; Sikivie, P. et al.
Partner: UNT Libraries Government Documents Department

White paper : the fourth amendment : implications for radiological and nuclear detection.

Description: The need to improve the radiation detection architecture has given rise to increased concern over the potential of equipment or procedures to violate the Fourth Amendment. Protecting the rights guaranteed by the Constitution is a foremost value of every government agency. However, protecting U.S. residents and assets from potentially catastrophic threats is also a crucial role of government. In the absence of clear precedent, the fear of potentially violating rights could lead to the rejection of effective and reasonable means that could reduce risks, possibly savings lives and assets. The goal of this document is not to apply case law to determine what the precedent may be if it exists, but rather provide a detailed outline that defines searches and seizures, identifies what precedent exists and what precedent doesn't exist, and explore what the existing (and non-existing) precedent means for the use of radiation detection used inside the nation's borders.
Date: January 1, 2010
Creator: Levey, Brandon Seth
Partner: UNT Libraries Government Documents Department

High Density Nano-Electrode Array for Radiation Detection

Description: Bulk single crystals of Cd1-xZnxTe (x=0.04 to x=0.2) compound semiconductor is used for room temperature radiation detection. The production of large volume of Cd1-xZnxTe with low defect density is expensive. As a result there is a growing research interest in the production of nanostructured compound semiconductors such as Cd1-xZnxTe in an electrochemical route. In this investigation, Cd1-xZnxTe ternary compound semiconductor, referred as CZT, was electrodeposited in the form of nanowires onto a TiO2 nanotubular template from propylene carbonate as the non-aqueous electrolyte, using a pulse-reverse electrodeposition process at 130 ºC. The template acted as a support in growing ordered nanowire of CZT which acts as a one dimensional conductor. Cyclic Voltammogram (CV) studies were conducted in determining the potentials for the growth of nanowires of uniform stoichiometry. The morphologies and composition of CZT were characterized by using SEM, TEM and XRD. The STEM mapping carried out on the nanowires showed the uniform distribution of Cd, Zn and Te elements. TEM image showed that the nanowires were polycrystalline in nature. The Mott-Schottky analysis carried on the nanowires showed that the nanowires were a p-type semiconductor. The carrier density, band gap and resistivity of the Cd0.9Zn0.1Te nanowires were 4.29x1013 cm-3, 1.56 eV and 2.76x1011Ω-cm respectively. The high resistivity was attributed to the presence of deep defect states such as cadmium vacancies or Te antisites which were created by the anodic cycle of the pulse-reverse electrodeposition process. Stacks of series connected CZT nanowire arrays were tested with different bias potentials. The background current was in the order of tens of picoamperes. When exposed to radiation source Amerecium-241 (60 KeV, 4 μCi), the stacked CZT nanowires arrays showed sensing behavior. The sensitivity of the nanowire arrays increased as the number of stacks increased. The preliminary results indicate that the CZT nanowire arrays can be ...
Date: May 7, 2010
Creator: Misra, Mano
Partner: UNT Libraries Government Documents Department


Description: A phoswich radiation detector is comprised of a phosphor sandwich in which several different phosphors are viewed by a common photomultiplier. By selecting the appropriate phosphors, this system can be used to simultaneously measure multiple radiation types (alpha, beta, gamma and/or neutron) with a single detector. Differentiation between the signals from the different phosphors is accomplished using digital pulse shape discrimination techniques. This method has been shown to result in accurate discrimination with highly reliable and versatile digital systems. This system also requires minimal component count (i.e. only the detector and a computer for signal processing). A variety of detectors of this type have been built and tested including: (1) a triple phoswich system for alpha/beta/gamma swipe counting, (2) two well-type detectors for measuring low levels of low energy photons in the presence of a high energy background, (3) a large area detector for measuring beta contamination in the presence of a photon background, (4) another large area detector for measuring low energy photons from radioactive elements such as uranium in the presence of a photon background. An annular geometry, triple phoswich system optimized for measuring alpha/beta/gamma radiation in liquid waste processing streams is currently being designed.
Date: April 15, 2003
Creator: Miller, William H. & Leon, Manuel Diaz de
Partner: UNT Libraries Government Documents Department