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in creator/contributor: "Bell, Z. W."

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Feasibility of using prompt neutron capture gamma rays to detect mercury

This report describes a study to determine the feasibility to use neutrons to probe hidden spaces within buildings for the presence of mercury. The study was performed in four phases: First a search of the scientific literature was performed to ascertain the behavior of mercury subsequent to the capture of a thermal or near-thermal neutron. Second, a Monte Carlo investigation (using the code MCNP) of the effects of neutrons on materials expected to be found near and/or surrounding the mercury w… more

Date: October 1, 1993

Creator: Bell, Z.W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Evaluation of photoneutron production at high energy LINACS

This report describes an estimate of neutron production at a 9 MeV LINAC, and the potential for photoactivation of materials present at the LINAC facility. It was found that only isotopes of U, W, Ta, and Pb had daughters whose activities might be measurable. The LINAC was found to be capable of producing in the neighborhood of 10{sup 10} neutrons/second from these heavy metals, and that subsequent neutron activation might be more of a concern. Monte Carlo simulation of neutron transport and ca… more

Date: April 24, 1995

Creator: Bell, Z.W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Detection of concealed mercury with thermal neutrons

In the United States today, governments at all levels and the citizenry are paying increasing attention to the effects, both real and hypothetical, of industrial activity on the environment. Responsible modem industries, reflecting this heightened public and regulatory awareness, are either substituting benign materials for hazardous ones, or using hazardous materials only under carefully controlled conditions. In addition, present-day environmental consciousness dictates that we deal responsib… more

Date: August 18, 1994

Creator: Bell, Z.W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Monte Carlo study of neutronics properties of the modular storage geometry

The modular storage vault (MSV) geometry was investigated for its effects on the spectrum of neutrons from the spontaneous and induced fission of plutonium. Zinc alloy and aluminum alloy plates that will house neutron detectors and weight sensors were included. It was found that because of the large number of captures by plutonium and the steel and concrete MSV structure, only 12% of the neutron spectrum in the vicinity of the detector position was thermalized and over half of the neutrons inci… more

Date: September 1995

Creator: Bell, Z. W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

SmartShelf{trademark}: Report of activities for fiscal year 1996

The SmartShelf{trademark} system is designated to maintain an up-to-the-minute inventory of containers or other assets. Through the use of Dallas Semiconductor touch memory devices affixed to containers and entrusted to authorized operators, the system can determine which operator added or removed which container and when the transaction occurred. Through the use of a PC-based data base system, reports of the current status of all containers and nodes can be generated in minutes. This report co… more

Date: December 5, 1996

Creator: Bell, Z.W.; Lawson, R.L. & Long, C.D.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

SmartShelf{trademark}: Report of activities for fiscal year 1997

This report covers activities relating to the SmartShelf{trademark} project during the period October 1, 1996, through September 30, 1997. During this year, project team members have advanced the state of both the hardware and software through a six-month-long test that exercised all hardware and nearly all software components. Second-generation node hardware was constructed and tested with the system and it was found that components supplied by Dallas Semiconductor did not meet the manufacture… more

Date: September 26, 1997

Creator: Bell, Z.W. & Lawson, R.L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Summary report on four Oak Ridge sensors for enhancing nuclear safeguards neutron detectors

The need for monitoring weapons grade Pu in nuclear facilities worldwide was addressed with four radiation detector technologies being developed at Y-12 and ORNL. This paper describes experimental results of 4 Oak Ridge Sensors for Enhancing Nuclear Safeguards (ORSENS) neutron detector technologies and includes the potential application, cost, and advantages for each. These are a {sup 6}LiF- ZnS(Ag) thermal neutron scintillator coupled to a wavelength-shifting optical fiber, a CdWO{sub 4} based… more

Date: August 1, 1997

Creator: Williams, J. A.; Clark, R. L.; Hutchinson, D. P.; Miller, V. C.; Ramsey, J. A.; Bell, Z. W. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Photoneutron source based on a compact 10 MeV betatron

Accelerator-based photoneutron sources have enjoyed wide use and offer the advantages of long term stability, ease of control and absence of radioactive materials. The authors report here measurements of the yield of photoneutrons from a neutron generator using a compact betatron (466 kg total weight, 900 by 560 by 350 mm betatron dimensions) at the Institute of Introscopy of the Tomsk Polytechnic University. Electrons were accelerated to energies up to 10 MeV and produced a bremsstrahlung beam… more

Date: May 8, 1998

Creator: Bell, Z.W.; Chaklov, V.L. & Golovkov, V.M.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

CdWO4-Boron FY 2000 Task 4 Completion Report

The fabrication of boron-covered crystal scintillation detectors is described. Bulk boron-loaded epoxy material was cast and cut into 0.5 mm-thick wafers that were mounted on CdWO{sub 4} and CsI(Tl) crystals. The crystals were mounted on miniature photomultiplier tubes and gamma spectra were obtained with the detectors. The ability of these small detectors to produce spectra that can be analyzed to provide isotopic identification has been demonstrated. In addition, the detector can produce a si… more

Date: February 1, 2001

Creator: Bell, Z. W. & Moyer, M. W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Portable Detector FY 2000 Task 4 Completion Report

Date: February 1, 2001

Creator: Bell, Z. W. & Moyer, M. W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Automated Systems for Safeguarding and Accountancy of Stored Nuclear Material (for proceedings of ESARDA 21st Annual Meeting, Sevilla, Spain May 4-6, 1999

Oak Ridge has developed several sensor systems that are capable of providing unattended monitoring of the physical and/or assigned attributes associated with stored nuclear materials. These systems include the Continuous Automated Vault Inventory System (CAVISTM), SmartShelfTM, and the ReflectoActive Seal System TM. Each of these systems can be implemented independently or may be integrated with existing systems through the Graphical Facility Information Center or GraFICTM software package. Gra… more

Date: May 1, 1999

Creator: Baldwin, K. M.; Bell, Z. W.; Dunigan, J. J.; Gaby, J. E.; Hickerson, T. W.; Lawson, R. L. et al.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Boron-Loaded Silicone Rubber Scintillators

Silicone rubber received attention as an alternative to polyvinyltoluene in applications in which the scintillator is exposed to high doses because of the increased resistance of the rubber to the formation of blue-absorbing color centers. Work by Bowen, et al., and Harmon, et al., demonstrated their properties under gamma/x-ray irradiation, and Bell, et al. have shown their response to thermal neutrons. This last work, however, provided an example of a silicone in which both the boron and the … more

Date: May 12, 2003

Creator: Bell, Z. W.; Maya, L.; Brown, G. M. & Sloop, F. V. Jr

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Neutron Detection with a Cryogenic Spectrometer

Cryogenic calorimeters are used for x-ray detection because of their exquisite energy resolution and have found application in x-ray astronomy, and the search for dark matter. These devices operate by detecting the heat pulse produced by ionization in an absorber cooled to temperatures below 1 K. Such temperatures are needed to lower the absorber's heat capacity to the point that the deposition of even a few eV results in a measurable temperature excursion. Typical absorbers for dark matte… more

Date: June 23, 2003

Creator: Bell, Z. W.; Lamberti, V. E.; Carpenter, D. A. & Cristy, S. S.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

HotSpotter? Neutron/Gamma Detector

The HotSpotter{trademark} Neutron/Gamma Detector combines in a single detecting module high sensitivity to gamma rays up to 3 MeV and sensitivity to neutrons. Using a 15 mm cubic CdWO{sub 4} (cadmium tungstate) crystal mounted on a 25 mm photomultiplier, the instrument realizes a factor of 5 increased photopeak efficiency over NaI(Tl) at 1 MeV, and a factor of 2 improvement over CsI(Tl). The addition of a 0.5 mm layer of {sup 10}B- impregnated epoxy covering the crystal provides neutron sensiti… more

Date: April 1, 2003

Creator: Bell, Z. W.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

ReflectoActive{trademark} Seals for Materials Control and Accountability

The ReflectoActive{trademark} Seals system, a continuously monitored fiber optic, active seal technology, provides real-time tamper indication for large arrays of storage containers. The system includes a PC running the RFAS software, an Immediate Detection Unit (IDU), an Optical Time Domain Reflectometer (OTDR), links of fiber optic cable, and the methods and devices used to attach the fiber optic cable to the containers. When a breach on any of the attached fiber optic cable loops occurs, the… more

Date: January 1, 2002

Creator: Richardson, G. D.; Younkin, J. R. & Bell, Z. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Continuous Holdup Measurements with Silicon P-I-N Photodiodes

We report on the behavior of silicon P-I-N photodiodes used to perform holdup measurements on plumbing. These detectors differ from traditional scintillation detectors in that no high-voltage is required, no scintillator is used (gamma and X rays are converted directly by the diode), and they are considerably more compact. Although the small size of the diodes means they are not nearly as efficient as scintillation detectors, the diodes' size does mean that a detector module, including one… more

Date: May 1, 2002

Creator: Bell, Z. W.; Oberer, R. B.; Williams, J. A.; Smith, D. E. & Paulus, M. J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Superconducting Gamma/Neutron Spectrometer Task 1 Completion Report Evaluation of Candidate Neutron-Sensitive Materials

A review of the scientific literature regarding boron- and lithium-containing compounds was completed. Information such as Debye temperature, heat capacity, superconductivity properties, physical and chemical characteristics, commercial availability, and recipes for synthesis was accumulated and evaluated to develop a list of neutron-sensitive materials likely to perform properly in the spectrometer. The best candidate borides appear to be MgB{sub 2} (a superconductor with T{sub c} = 39 K), B{s… more

Date: June 20, 2002

Creator: Bell, Z.W. & Lamberti, V.E.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

A Digital Signal Processor Based Controller for Inventory Confirmation Using Mass-Spring Devices

Successful inventory confirmation measurements in SNM storage monitoring scenarios require electronic systems that are capable of long-term, reliable operation. Reliability can be improved by using systems with a minimum of inaccessible active components. A resonant weight pad has been designed to determine item mass with only two passive components located at the SNM storage point. During operation, the resonant weight pad and the monitored item become a mass-spring system, whose resonant freq… more

Date: June 1, 2002

Creator: Stinson, B. J. & Bell, Z. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

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Neutron Detection with Cryogenics and Semiconductors

The common methods of neutron detection are reviewed with special attention paid to the application of cryogenics and semiconductors to the problem. The authors' work with LiF- and boron-based cryogenic instruments is described as well as the use of CdTe and HgI{sub 2} for direct detection of neutrons.

Date: March 10, 2005

Creator: Bell, Z. W.; Carpenter, D. A.; Cristy, S. S. & Lamberti, V. E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Brighter Screens for Nondestructive Digital X-ray Radiography

Fine resolution, bright X-ray screens are needed for digital radiography and material characterization at the Y-12 National Security Complex (Y-12). Current technology is simply not adequate for transferring high-energy X-ray images to visible light for demanding digital applications. Low energy radiography and especially emerging tomographic technologies are severely hampered for Y-12 nondestructive evaluation (NDE) applications by dim screens with poor resolution. Also, the development of mor… more

Date: September 15, 2003

Creator: Miller, A. C., Jr.; Bell, Z. W. & Carpenter, D. A.

Item Type: Report

Partner: UNT Libraries Government Documents Department

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Specific Heat Measurements of TiB(2)[subscript] and (6)[superscript]LiF from 0.5 to 30K

The specific heats of TiB{sub 2} and {sup 6}LiF have been measured from 0.5 to 30 K as part of a larger project in the construction of a neutron spectrometer. For this application, the measured specific heats were used to extrapolate the specific heats down to 0.1 K with lattice, electronic, and Schottky equations for the respective samples. The resultant specific heat values at 0.1 K for TiB{sub 2} and {sup 6}LiF are 4.08 x 10{sup -4} {+-} 0.27 x 10{sup -4} J/K/mol and 9.19 x 10{sup -9} {+-} 0… more

Date: March 28, 2005

Creator: Lang, B. E.; Marcus, H. D.; Woodfield, B. F.; Burger, A.; Utupal, N. R.; Lamberti, V. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Cryogenic Neutron Spectrometer Development

Cryogenic microcalorimeter detectors operating at temperatures around {approx}0.1 K have been developed for the last two decades, driven mostly by the need for ultra-high energy resolution (<0.1%) in X-ray astrophysics and dark matter searches [1]. The Advanced Detector Group at Lawrence Livermore National Laboratory has developed different cryogenic detector technologies for applications ranging from X-ray astrophysics to nuclear science and non-proliferation. In particular, we have adapted… more

Date: March 8, 2006

Creator: Niedermayr, T.; Hau, I. D.; Friedrich, S.; Burger, A.; Roy, U. N. & Bell, Z. W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Mercury detection with thermal neutrons

No Description Available.

Date: September 19, 1994

Creator: Bell, Z. W.

Item Type: Report

Partner: UNT Libraries Government Documents Department