Exotic physics: search for scalar leptoquark pairs decaying to nu nu-bar qq-bar in p anti-p collisions at s**(1/2) = 1.96 tev (open access)

Exotic physics: search for scalar leptoquark pairs decaying to nu nu-bar qq-bar in p anti-p collisions at s**(1/2) = 1.96 tev

We report on a search for the pair production of scalar leptoquarks, LQ, using 191 pb{sup -1} of proton-antiproton collision data recorded by the CDF experiment during Run II of the Tevatron. The leptoquarks are sought via their decay into a neutrino and quark yielding missing transverse energy and several jets of large transverse energy. No evidence for leptoquark production is observed, and limits are set on {sigma}(p{bar p} {yields} LQ{ovr OQ}X {yields} v{bar v}q{bar q}X). Using a next-to-leading order theoretical prediction of the cross section for scalar leptoquark production, we exclude first-generation leptoquarks in the mass interval 78 to 117 GeV/c{sup 2} at the 95% confidence level for BR(LQ {yields} vq) = 100%.
Date: October 25, 2004
Creator: Acosta, D.
Object Type: Report
System: The UNT Digital Library
A COST EFFECTIVE MULTI-SPECTRAL SCANNER FOR NATURAL GAS DETECTION (open access)

A COST EFFECTIVE MULTI-SPECTRAL SCANNER FOR NATURAL GAS DETECTION

The objective of this project is to design, fabricate and field demonstrate a cost effective, multi-spectral scanner for natural gas leak detection in transmission and distribution pipelines. During the first year of the project, a laboratory version of the multi-spectral scanner was designed, fabricated, and tested at En'Urga Inc. The multi-spectral scanner was also evaluated using a blind DoE study at RMOTC. The performance of the scanner was inconsistent during the blind DoE study. However, most of the leaks were outside the view of the multi-spectral scanner. Therefore, a definite evaluation of the capability of the scanner was not obtained. Despite the results, sufficient number of plumes was detected fully confirming the feasibility of the multi-spectral scanner. During the second year, a rugged prototype scanner will be developed and evaluated, both at En'Urga Inc. and any potential field sites.
Date: October 25, 2004
Creator: Sivathanu, Yudaya; Lim, Jongmook & Narayanan, Vinoo
Object Type: Report
System: The UNT Digital Library
Handling the Handbag Diagram in Compton Scattering on the Proton (open access)

Handling the Handbag Diagram in Compton Scattering on the Proton

Poincare invariance, gauge invariance, conservation of parity and time reversal invariance are respected in an impulse approximation evaluation of the handbag diagram. Proton wave functions, previously constrained by comparison with measured form factors, that incorporate the influence of quark transverse and orbital angular momentum (and the corresponding violation of proton helicity conservation) are used. Computed cross sections are found to be in reasonably good agreement with early measurements. The helicity correlation between the incident photon and outgoing proton, K{sub LL}, is both large and positive at back angles. For photon laboratory energies of {le} 6 GeV, we find that K{sub LL} {ne} A{sub LL}, D{sub LL} {ne} 1, and that the polarization P can be large.
Date: February 25, 2004
Creator: Miller, Gerald A.
Object Type: Article
System: The UNT Digital Library
Associations between classroom CO2 concentrations and student attendance in Washington and Idaho (open access)

Associations between classroom CO2 concentrations and student attendance in Washington and Idaho

Student attendance in American public schools is a critical factor in securing limited operational funding. Student and teacher attendance influence academic performance. Limited data exist on indoor air and environmental quality (IEQ) in schools, and how IEQ affects attendance, health, or performance. This study explored the association of student absence with measures of indoor minus outdoor carbon dioxide concentration (dCO{sub 2}). Absence and dCO{sub 2} data were collected from 409 traditional and 25 portable classrooms from 14 schools located in six school districts in the states of Washington and Idaho. Study classrooms had individual heating, ventilation, and air conditioning (HVAC) systems, except two classrooms without mechanical ventilation. Classroom attributes, student attendance and school-level ethnicity, gender, and socioeconomic status (SES) were included in multivariate modeling. Forty-five percent of classrooms studied had short-term indoor CO{sub 2} concentrations above 1000 parts-per-million (ppm). A 1000 ppm increase in dCO{sub 2} was associated (p < 0.05) with a 0.5% to 0.9% decrease in annual average daily attendance (ADA), corresponding to a relative 10% to 20% increase in student absence. Outside air (ventilation) rates estimated from dCO{sub 2} and other collected data were not associated with absence. Annual ADA was 2% higher (p < 0.0001) in …
Date: July 25, 2004
Creator: Shendell, Derek G.; Prill, Richard; Fisk, William J.; Apte, Michael G.; Blake, David & Faulkner, David
Object Type: Article
System: The UNT Digital Library
Electron beam diagnostic for space charge measurement of an ion beam (open access)

Electron beam diagnostic for space charge measurement of an ion beam

A non-perturbing electron beam diagnostic system for measuring the charge distribution of an ion beam is developed for Heavy Ion Fusion (HIF) beam physics studies. Conventional diagnostics require temporary insertion of sensors into the beam, but such diagnostics stop the beam, or significantly alter its properties. In this diagnostic a low energy, low current electron beam is swept transversely across the ion beam; the measured electron beam deflection is used to infer the charge density profile of the ion beam. The initial application of this diagnostic is to the Neutralized Transport Experiment (NTX), which is exploring the physics of space-charge-dominated beam focusing onto a small spot using a neutralizing plasma. Design and development of this diagnostic and performance with the NTX ion beamline is presented.
Date: September 25, 2004
Creator: Roy, Prabir K.; Yu, Simon S.; Henestroza, Enrique; Eylon, Shmuel; Shuman, Derek B.; Ludvig, Jozsef et al.
Object Type: Article
System: The UNT Digital Library
Simulation of DIII-D Flat q Discharges (open access)

Simulation of DIII-D Flat q Discharges

The Advanced Tokamak plasma configuration has significant potential for the economical production of fusion power. Research on various tokamak experiments are pursuing these plasmas to establish high {beta}, high bootstrap current fraction, 100% noninductive current, and good energy confinement, in a quasi-stationary state. One candidate is the flat q discharge produced in DIII-D, where the safety factor varies from 2.0 on axis, to slightly below 2.0 at the minimum, and then rises to about 3.5 at the 95% surface. This plasma is prototypical of those studied for power plants in the ARIES tokamak studies. The plasma is produced by ramping up the plasma current and ramping down the toroidal field throughout the discharge. The plasma current reaches 1.65 MA, and the toroidal field goes from 2.25 to 1.6 T. The q{sub min} remains high and at large radius, {rho} {approx} 0.6. The plasma establishes an internal transport barrier in the ion channel, and transitions to H-mode. The free-boundary Tokamak Simulation Code (TSC) is being used to model the discharge and project the impact of changes in the plasma current, toroidal field, and injected power programming.
Date: June 25, 2004
Creator: Kessel, C.E.; Garofalo, A. & Terpstra, T.
Object Type: Report
System: The UNT Digital Library
Field Test Program to Develop Comprehensive Design, Operating and Cost Data for Mercury Control Systems on Non-Scrubbed Coal-Fired Boilers, Quarterly Technical Report: July-September 2004 (open access)

Field Test Program to Develop Comprehensive Design, Operating and Cost Data for Mercury Control Systems on Non-Scrubbed Coal-Fired Boilers, Quarterly Technical Report: July-September 2004

With the nation's coal-burning utilities facing the possibility of tighter controls on mercury pollutants, the U.S. Department of Energy is funding projects that could offer power plant operators better ways to reduce these emissions at much lower costs. Mercury is known to have toxic effects on the nervous systems of humans and wildlife. Although it exists only in trace amounts in coal, mercury is released when coal burns and can accumulate on land and in water. In water, bacteria transform the metal into methylmercury, the most hazardous form of the metal. Methylmercury can collect in fish and marine mammals in concentrations hundreds of thousands times higher than the levels in surrounding waters. One of the goals of DOE is to develop technologies by 2005 that will be capable of cutting mercury emissions 50 to 70 percent at well under one-half of projected DOE/EPA early cost estimates. ADA Environmental Solutions (ADA-ES) is managing a project to test mercury control technologies at full scale at four different power plants from 2000-2003. The ADA-ES project is focused on those power plants that are not equipped with wet flue gas desulfurization systems. ADA-ES has developed a portable system that was tested at four different …
Date: October 25, 2004
Creator: Bustard, Jean & Schlager, Richard
Object Type: Report
System: The UNT Digital Library
The Impact of De-Inventory and Deactivation on the Characterization of F-Canyon Solid Low Level Waste (open access)

The Impact of De-Inventory and Deactivation on the Characterization of F-Canyon Solid Low Level Waste

The F-Canyon Facility was constructed in the early 1950's for the separation and recovery of 239Pu, 237Np and 238U from irradiated natural or depleted uranium targets and fuel rods using the PUREX (Plutonium - Uranium Extraction) process. In the PUREX process, the irradiated target or fuel slugs are received from the reactor areas of the Receiving Basin for Offsite Fuels, charged to the dissolvers and dissolved in nitric acid. The resulting solution contains primarily uranium-238 and smaller amounts of plutonium, uranium-235, and fission products. The primary operations conducted in F-Canyon include the separation and recovery of Pu-239 and U-238 from irradiated materials in the stabilization of plutonium residues. Since 1995, the F-Canyon Complex has been operating to stabilize ''at risk'' nuclear materials and spent fuel from throughout the DOE complex. That mission is complete. Since the last low level waste characterization, the F-Canyon has been implementing the PUREX Operations Suspension Plan and the Deactivation Project Plan.
Date: March 25, 2004
Creator: WILSON, STEVE
Object Type: Report
System: The UNT Digital Library
Compatible Spatial Discretizations for Partial Differential Equations (open access)

Compatible Spatial Discretizations for Partial Differential Equations

From May 11--15, 2004, the Institute for Mathematics and its Applications held a hot topics workshop on Compatible Spatial Discretizations for Partial Differential Equations. The numerical solution of partial differential equations (PDE) is a fundamental task in science and engineering. The goal of the workshop was to bring together a spectrum of scientists at the forefront of the research in the numerical solution of PDEs to discuss compatible spatial discretizations. We define compatible spatial discretizations as those that inherit or mimic fundamental properties of the PDE such as topology, conservation, symmetries, and positivity structures and maximum principles. A wide variety of discretization methods applied across a wide range of scientific and engineering applications have been designed to or found to inherit or mimic intrinsic spatial structure and reproduce fundamental properties of the solution of the continuous PDE model at the finite dimensional level. A profusion of such methods and concepts relevant to understanding them have been developed and explored: mixed finite element methods, mimetic finite differences, support operator methods, control volume methods, discrete differential forms, Whitney forms, conservative differencing, discrete Hodge operators, discrete Helmholtz decomposition, finite integration techniques, staggered grid and dual grid methods, etc. This workshop seeks to foster …
Date: November 25, 2004
Creator: Arnold, Douglas, N.
Object Type: Report
System: The UNT Digital Library
Harmonic cascade FEL designs for LUX, a facility for ultrafast x-ray science (open access)

Harmonic cascade FEL designs for LUX, a facility for ultrafast x-ray science

LUX is a design study to develop concepts for future ultrafast x-ray facilities. Presently, LUX is based on an electron beam accelerated to {approx}3-GeV energy in a superconducting, recirculating linac. Included in the design are multiple free-electron laser (FEL) beamlines which use the harmonic cascade approach to produce coherent XUV and soft X-ray emission beginning with a strong input seed at {approx}200-nm wavelength obtained from a ''conventional'' laser. Each cascade module generally operates in the low-gain regime and is composed of a radiator together with a modulator section, separated by a magnetic chicane. The chicane temporally delays the electron beam pulse in order that a ''virgin'' pulse region (with undegraded energy spread) be brought into synchronism with the radiation pulse. For a given cascade, the output photon energy can be selected over a wide range by varying the seed laser wavelength and the field strength in the undulators. We present numerical simulation results, as well as those from analytical models, to examine certain aspects of the predicted FEL performance. We also discuss lattice considerations pertinent to harmonic cascade FELs, some sensitivity studies and requirements on the undulator alignment, and temporal pulse evolution initiated by short input radiation seeds.
Date: August 25, 2004
Creator: Corlett, John; Fawley, William; Penn, Gregory; Wan, Weishi; Zholents, A.; Reinsch, M. et al.
Object Type: Article
System: The UNT Digital Library
Development of a functionalized Xenon biosensor (open access)

Development of a functionalized Xenon biosensor

NMR-based biosensors that utilize laser-polarized xenon offer potential advantages beyond current sensing technologies. These advantages include the capacity to simultaneously detect multiple analytes, the applicability to in vivo spectroscopy and imaging, and the possibility of remote amplified detection. Here we present a detailed NMR characterization of the binding of a biotin-derivatized caged-xenon sensor to avidin. Binding of functionalized xenon to avidin leads to a change in the chemical shift of the encapsulated xenon in addition to a broadening of the resonance, both of which serve as NMR markers of ligand-target interaction. A control experiment in which the biotin-binding site of avidin was blocked with native biotin showed no such spectral changes, confirming that only specific binding, rather than nonspecific contact, between avidin and functionalized xenon leads to the effects on the xenon NMR spectrum. The exchange rate of xenon (between solution and cage) and the xenon spin-lattice relaxation rate were not changed significantly upon binding. We describe two methods for enhancing the signal from functionalized xenon by exploiting the laser-polarized xenon magnetization reservoir. We also show that the xenon chemical shifts are distinct for xenon encapsulated in different diastereomeric cage molecules. This demonstrates the potential for tuning the encapsulated xenon …
Date: March 25, 2004
Creator: Spence, Megan M.; Ruiz, E. Janette; Rubin, Seth M.; Lowery, Thomas J.; Winssinger, Nicolas; Schultz, Peter G. et al.
Object Type: Article
System: The UNT Digital Library

Rail Alignment Environmental Impact Statement Information Session

None
Date: May 25, 2004
Creator: Sweeney, R.
Object Type: Presentation
System: The UNT Digital Library
2004 Atomic and Molecular Interactions Gordon Research Conference (open access)

2004 Atomic and Molecular Interactions Gordon Research Conference

The 2004 Gordon Research Conference on Atomic and Molecular Interactions was held July 11-16 at Colby-Sawyer College, New London, New Hampshire. This latest edition in a long-standing conference series featured invited talks and contributed poster papers on dynamics and intermolecular interactions in a variety of environments, ranging from the gas phase through surfaces and condensed media. A total of 90 conferees participated in the conference.
Date: October 25, 2004
Creator: Dagdigian, Dr. Paul J.
Object Type: Article
System: The UNT Digital Library
Seismic Consequence Abstraction (open access)

Seismic Consequence Abstraction

The primary purpose of this model report is to develop abstractions for the response of engineered barrier system (EBS) components to seismic hazards at a geologic repository at Yucca Mountain, Nevada, and to define the methodology for using these abstractions in a seismic scenario class for the Total System Performance Assessment - License Application (TSPA-LA). A secondary purpose of this model report is to provide information for criticality studies related to seismic hazards. The seismic hazards addressed herein are vibratory ground motion, fault displacement, and rockfall due to ground motion. The EBS components are the drip shield, the waste package, and the fuel cladding. The requirements for development of the abstractions and the associated algorithms for the seismic scenario class are defined in ''Technical Work Plan For: Regulatory Integration Modeling of Drift Degradation, Waste Package and Drip Shield Vibratory Motion and Seismic Consequences'' (BSC 2004 [DIRS 171520]). The development of these abstractions will provide a more complete representation of flow into and transport from the EBS under disruptive events. The results from this development will also address portions of integrated subissue ENG2, Mechanical Disruption of Engineered Barriers, including the acceptance criteria for this subissue defined in Section 2.2.1.3.2.3 of the …
Date: October 25, 2004
Creator: Gross, M.
Object Type: Report
System: The UNT Digital Library
Hydrogen Storage Properties of the Tetrahydrofuran Treated Magnesium (open access)

Hydrogen Storage Properties of the Tetrahydrofuran Treated Magnesium

The electronic structure, crystalline feature and morphology of the tetrahydrofuran (THF) treated magnesium, along with its hydriding and dehydriding properties have been investigated. The THF treated magnesium absorbs 6.3 wt per cent hydrogen at 723K and 3.5 MPa. After hydrogenation, in addition to the expected MgH2, a new less-stable hydride phase appears at 673K, but not at a lower temperature. Desorption produces 5.5 wt per cent hydrogen at 723K against a back pressure of 1.3 Pa after 20 cycles of hydriding-dehydriding. The THF treatment improves the kinetics of hydrogen absorption and desorption significantly. From 723K to 623K, the THF treated Mg demonstrates acceptable reaction rates. XPS studies show that tetrahydrofuran treatment causes the electronic energy state of the magnesium surface atoms to change, but the XRD studies show the crystal structure remains unchanged. Metallographic observation of the bulk hydrides of THF treated magnesium reveal they are poly-crystalline wi th the wide-spreading slip bands and twins within the crystals, indicating the phase transformation upon hydriding causes serious stress and distortion. It appears this microstructural deformation explains the much higher energy requirements (higher pressure and temperature) for magnesium hydrogenation than the simple lattice expansion that accompany hydrogen uptake for LaNi5 and FeTi.
Date: May 25, 2004
Creator: AU, MING
Object Type: Article
System: The UNT Digital Library

Managing the Yucca Mountain Project's Cultural Resources

None
Date: May 25, 2004
Creator: Bishop, L.
Object Type: Presentation
System: The UNT Digital Library
Recent physics results from CDF and D0 (open access)

Recent physics results from CDF and D0

Recent physics results from CDF and D0 on heavy flavor physics, electroweak precision measurements, top physics, QCD and searches for new physics are discussed. The results are based on approximately 140 pb{sup -1} of data collected at {radical}s = 1.96 TeV between 2002 and 2003.
Date: February 25, 2004
Creator: Thomson, Evelyn
Object Type: Article
System: The UNT Digital Library
ATMOSPHERIC DISPERSAL AND DEPOSITION OF TEPHRA FROM A POTENTIAL VOLCANIC ERUPTION AT YUCCA MOUNTAIN, NEVADA (open access)

ATMOSPHERIC DISPERSAL AND DEPOSITION OF TEPHRA FROM A POTENTIAL VOLCANIC ERUPTION AT YUCCA MOUNTAIN, NEVADA

The purpose of this model report is to provide documentation of the conceptual and mathematical model (Ashplume) for atmospheric dispersal and subsequent deposition of ash on the land surface from a potential volcanic eruption at Yucca Mountain, Nevada. This report also documents the ash (tephra) redistribution conceptual model. These aspects of volcanism-related dose calculation are described in the context of the entire igneous disruptive events conceptual model in ''Characterize Framework for Igneous Activity'' (BSC 2004 [DIRS 169989], Section 6.1.1). The Ashplume conceptual model accounts for incorporation and entrainment of waste fuel particles associated with a hypothetical volcanic eruption through the Yucca Mountain repository and downwind transport of contaminated tephra. The Ashplume mathematical model describes the conceptual model in mathematical terms to allow for prediction of radioactive waste/ash deposition on the ground surface given that the hypothetical eruptive event occurs. This model report also describes the conceptual model for tephra redistribution from a basaltic cinder cone. Sensitivity analyses and model validation activities for the ash dispersal and redistribution models are also presented. Analyses documented in this model report update the previous documentation of the Ashplume mathematical model and its application to the Total System Performance Assessment (TSPA) for the License Application …
Date: October 25, 2004
Creator: Harrington, C.
Object Type: Report
System: The UNT Digital Library
Reactive Multiphase Behavior of CO2 in Saline Aquifers Beneath the Colorado Plateau (open access)

Reactive Multiphase Behavior of CO2 in Saline Aquifers Beneath the Colorado Plateau

Field and laboratory investigations of naturally occurring CO{sub 2}-reservoirs are being conducted to determine the characteristics of potential seal and reservoir units and the extent of the interactions that occur between the host rocks and the CO{sub 2} charged fluids. Efforts have focused on the Farnham Dome field, located in central Utah, the Springerville-St. Johns field in Arizona and New Mexico, and most recently, the Crystal Geyser-Salt Wash graben areas with their CO{sub 2}-charged geysers and springs in central Utah. At both the Springerville-St. Johns field and the central Utah CO{sub 2} spring area, there is evidence of extensive travertine deposits that document release of CO{sub 2} to the atmosphere. At Farnham Dome, calcite debris fields appear to be remnants of vein calcite and an earlier period of fluid leakage. The main achievements during this quarter are (1): preparation for a soil gas flux survey in October at the Crystal Geyser --Little Grand Wash fault zone, and the Salt Wash graben; (2) submission of an abstract to the upcoming Measurement, Monitoring and Verification session at the Fall AGU meeting; (3) submission of an invited abstract to the Gordon Conference on Hydrocarbon Resources; and (4) receipt of initial radiocarbon dates of …
Date: October 25, 2004
Creator: Allis, R. G.; Moore, J. & White, S.
Object Type: Report
System: The UNT Digital Library
Hybrid 320 Ton Off Highway Haul Truck: Quarterly Technical Status Report 7, DOE/AL68080-TSR07 (open access)

Hybrid 320 Ton Off Highway Haul Truck: Quarterly Technical Status Report 7, DOE/AL68080-TSR07

Analysis and results show hybrid system weight and efficiency affect productivity and fuel usage. Analysis shows equivalent hybrid benefits for adjacent size classes of mine truck. Preparations are ongoing for full power test. The battery cycling test protocol was modified.
Date: August 25, 2004
Creator: Salasoo, Lembit
Object Type: Report
System: The UNT Digital Library
Dissolution of Neptunium and Plutonium Oxides Using a Catalyzed Electrolytic Process (open access)

Dissolution of Neptunium and Plutonium Oxides Using a Catalyzed Electrolytic Process

This report discusses the scoping study performed to evaluate the use of a catalyzed electrolytic process for dissolving {sup 237}Np oxide targets that had been irradiated to produce {sup 238}Pu oxide. Historically, these compounds have been difficult to dissolve, and complete dissolution was obtained only by adding hydrofluoric acid to the nitric acid solvent. The presence of fluoride in the mixture is undesired because the fluoride ions are corrosive to tank and piping systems and the fluoride ions cause interferences in the spectrophotometric analyses. The goal is to find a dissolution method that will eliminate these issues and that can be incorporated into a processing system to support the domestic production and purification of {sup 238}Pu. This study evaluated the potential of cerium(IV) ions, a strong oxidant, to attack and dissolve the oxide compounds. In the dissolution process, the cerium(IV) ions are reduced to cerium(III) ions, which are not oxidants. Therefore, an electrolytic process was incorporated to continuously convert cerium(III) ions back to cerium(IV) ions so that they can dissolve more of the oxide compounds. This study showed that the neptunium and plutonium oxides were successfully dissolved and that more development work should be performed to optimize the procedure.
Date: October 25, 2004
Creator: Hylton, TD
Object Type: Report
System: The UNT Digital Library
44-BWR WASTE PACKAGE LOADING CURVE EVALUATION (open access)

44-BWR WASTE PACKAGE LOADING CURVE EVALUATION

The objective of this calculation is to evaluate the required minimum burnup as a function of initial boiling water reactor (BWR) assembly enrichment that would permit loading of spent nuclear fuel into the 44 BWR waste package configuration as provided in Attachment IV. This calculation is an application of the methodology presented in ''Disposal Criticality Analysis Methodology Topical Report'' (YMP 2003). The scope of this calculation covers a range of enrichments from 0 through 5.0 weight percent (wt%) U-235, and a burnup range of 0 through 40 GWd/MTU. This activity supports the validation of the use of burnup credit for commercial spent nuclear fuel applications. The intended use of these results will be in establishing BWR waste package configuration loading specifications. Limitations of this evaluation are as follows: (1) The results are based on burnup credit for actinides and selected fission products as proposed in YMP (2003, Table 3-1) and referred to as the ''Principal Isotopes''. Any change to the isotope listing will have a direct impact on the results of this report. (2) The results of 100 percent of the current BWR projected waste stream being able to be disposed of in the 44-BWR waste package with Ni-Gd Alloy …
Date: August 25, 2004
Creator: Scaglione, J.M.
Object Type: Report
System: The UNT Digital Library
The CDF Run IIb Silicon Detector (open access)

The CDF Run IIb Silicon Detector

Fermilab plans to deliver 5-15 fb{sup -1} of integrated luminosity to the CDF and D0 experiments. The current inner silicon detectors at CDF (SVXIIa and L00) will not tolerate the radiation dose associated with high luminosity running and will need to be replaced. A new readout chip (SVX4) has been designed in radiation-hard 0.25 {micro}m CMOS technology. Single sided sensors are arranged in a compact structure, called a stave, with integrated readout and cooling systems. This paper describes the general design of the Run IIb system, testing results of prototype electrical components (staves), and prototype silicon sensor performance before and after irradiation.
Date: February 25, 2004
Creator: Aoki, M.; Bacchetta, N. & al., S. Behari et
Object Type: Article
System: The UNT Digital Library
Radiation dose measurements of the insertion devices using radiachromic film dosimeters. (open access)

Radiation dose measurements of the insertion devices using radiachromic film dosimeters.

The Advanced Photon Source (APS) uses Nd-Fe-B permanent magnets in the insertion devices to produce x-rays for scientific research [1,2]. Earlier investigations have exhibited varying degrees of demagnetization of these magnets [3] due to irradiation from electron beams [4,5,6], {sup 60}Co {gamma}-rays [5], and high-energy neutrons [7,8]. Radiation-induced demagnetization has been observed in the APS insertion devices [9] and was first measured in December of 2001. Partial demagnetization has also been observed in insertion devices at the European Synchrotron Radiation Facility (ESRF) [4,6], where Nd-Fe-B permanent magnets are also used. Growing concern for the lifetime of APS insertion devices, as well as the permanent magnets that will be used in next-generation, high-power light sources, like the FEL [10,11], resulted from the partial demagnetization observations made at both facilities. This concern in relation to radiation-induced demagnetization spurred a long-term project to measure and analyze the absorbed doses received by the APS insertion devices. The project required a reliable photon high-dose dosimetry technique capable of measuring absorbed doses greater than 10{sup 6} rad, which was not readily available at the APS. Through a collaboration with the National Institute of Standards and Technology (NIST), one such technique using radiachromic films was considered, tested, …
Date: May 25, 2004
Creator: Alderman, J.; Semones, E. & Job, P. K.
Object Type: Report
System: The UNT Digital Library