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Quasi-free ({ital e,e`p}) reactions: the first look from CEBAF

Description: Coincidence cross sections for ({ital e,e{sup `}p}) quasi-elastic scattering were measured at CEBAF with high statistical precision for C, Fe, and Au targets for 0.6 {lt} Q{sup 2} {lt} 3.3 GeV{sup 2}. {ital E{sub m}} and {ital P{sub m}} distributions obtained from a preliminary analysis are in reasonable agreement with prior data from SLAC, The preliminary results are compared with a PWIA calculation to determine the nuclear transparency as a function of Q{sup 2} and A. A. Rosenbluth analysis to extract the longitudinal and transverse cross sections from these data is anticipated.
Date: November 1, 1996
Creator: Abbott, D.; Amatuoni, T. & Armstrong, C.
Partner: UNT Libraries Government Documents Department

Spent Fuel Background Report Volume I

Description: This report is an overview of current spent nuclear fuel management in the DOE complex. Sources of information include published literature, internal DOE documents, interviews with site personnel, and information provided by individual sites. Much of the specific information on facilities and fuels was provided by the DOE sites in response to the questionnaire for data for spent fuels and facilities data bases. This information is as accurate as is currently available, but is subject to revision pending results of further data calls. Spent fuel is broadly classified into three categories: (a) production fuels, (b) special fuels, and (c) naval fuels. Production fuels, comprising about 80% of the total inventory, are those used at Hanford and Savannah River to produce nuclear materials for defense. Special fuels are those used in a wide variety of research, development, and testing activities. Special fuels include fuel from DOE and commercial reactors used in research activities at DOE sites. Naval fuels are those developed and used for nuclear-powered naval vessels and for related research and development. Given the recent DOE decision to curtail reprocessing, the topic of main concern in the management of spent fuel is its storage. Of the DOE sites that have spent nuclear fuel, the vast majority is located at three sites-Hanford, INEL, and Savannah River. Other sites with spent fuel include Oak Ridge, West Valley, Brookhaven, Argonne, Los Alamos, and Sandia. B&W NESI Lynchburg Technology Center and General Atomics are commercial facilities with DOE fuel. DOE may also receive fuel from foreign research reactors, university reactors, and other commercial and government research reactors. Most DOE spent fuel is stored in water-filled pools at the reactor facilities. Currently an engineering study is being performed to determine the feasibility of using dry storage for DOE-owned spent fuel currently stored at various facilities. ...
Date: March 1, 1994
Creator: Abbott, D.
Partner: UNT Libraries Government Documents Department

Coherent {pi}{sup 0} photoproduction on the deuteron up to 4 GeV

Description: The differential cross section for D({gamma},d){pi}{sup 0} has been measured at deuteron center-of-mass angles of 90{degree} and 136{degree}. This work reports the first data for this reaction above a photon energy of 1 GeV, and permits a test of the apparent constituent counting rule and reduced nuclear amplitude behavior as observed in elastic ed scattering. Measurements were performed up to a photon energy of 4.0 GeV, and are in good agreement with previous lower energy measurements. Overall, the data are inconsistent with both constituent-counting rule and reduced nuclear amplitude predictions.
Date: July 1, 1999
Creator: Meekins, D. G.; Abbott, D. J. & Ahmidouch, A.
Partner: UNT Libraries Government Documents Department

Application of Clean Water (CWA) Section 404 compensatory wetland mitigation under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA)

Description: Pursuant to Section 404 of the Clean Water Act (CWA), activities resulting in the discharge of dredge or fill material into waters of the US, including wetlands, require permit authorization from the US Army Corps of Engineers (ACOE). As part of the Section 404 permitting process, compensatory wetland mitigation in the form of wetland enhancement, restoration, or construction may be required to off-set impacts sustained under a Section 404 permit. Under normal circumstances, compensatory mitigation is a relatively straight forward process; however, issues associated with mitigation become more complex at sites undergoing remediation under the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA), because on-site response/remedial actions involving dredged and fill material are not subject to the formal Section 404 permitting process. These actions are conducted in accordance with the substantive permitting requirements of the ACOE`s Nationwide and individual permitting programs. Wetland mitigatory requirements are determined through application of the US Environmental Protection Agency`s (USEPA`s) 040(b) (1) Guidelines promulgated in 40 CFR Part 230 and are implemented through compliance with substantive permitting requirements during the conduct of response/remedial actions. A programmatic approach for implementing wetland mitigatory requirements is being developed at a former US Department of Energy (DOE) uranium refinery undergoing CERCLA remediation in southwestern Ohio. The approach is designed to define the regulatory mechanism that will be used to integrate CWA driven wetland mitigatory requirements into the CERCLA process.
Date: June 1, 1994
Creator: Abbott, D.J. & Straub, C.A.
Partner: UNT Libraries Government Documents Department

Improved methods for measuring radioactive tracer accumulation and excretion by microarthropods, with applications for a mite species, Tyrophagus longior (Acarina, Acaridae)

Description: Radioisotope retention measurements of /sup 85/Sr and /sup 51/Cr in Tyrophagus longior (Gervais) (Acari: Acaridae) were fit to 2 and 1 component models. Biological half-life for the rapid component of both radioisotopes was about 10 hours, with assimilation of /sup 85/Sr being 62%. The identification of /sup 51/Cr turnover as gut clearance must remain tentative. An inexpensive disposable culture chamber for measuring radioisotope retention in microarthropods is described along with details of methodology.
Date: August 1, 1980
Creator: Abbott, D T & Crossley, Jr, D A
Partner: UNT Libraries Government Documents Department

Transportation capabilities study of DOE-owned spent nuclear fuel

Description: This study evaluates current capabilities for transporting spent nuclear fuel owned by the US Department of Energy. Currently licensed irradiated fuel shipping packages that have the potential for shipping the spent nuclear fuel are identified and then matched against the various spent nuclear fuel types. Also included are the results of a limited investigation into other certified packages and new packages currently under development. This study is intended to support top-level planning for the disposition of the Department of Energy`s spent nuclear fuel inventory.
Date: October 1, 1994
Creator: Clark, G.L.; Johnson, R.A.; Smith, R.W.; Abbott, D.G. & Tyacke, M.J.
Partner: UNT Libraries Government Documents Department

Quasielastic (e,e{prime}p) scattering at large momentum transfer

Description: Coincidence cross sections for (e, e{prime} p) quasi-elastic scattering were measured at CEBAF with high statistical precision for C, Fe, and Au targets for 0.6 < Q{sup 2} < 3.3 GeV{sup 2}. Missing energy and missing momentum distributions obtained from a preliminary analysis are in reasonable agreement with prior data from SLAC. The preliminary results are compared with a PWIA calculation to determine the nuclear transparency as a function of Q{sup 2} and A. At both A{sup 2} = 0.6 and Q{sup 2} = 1.8 GeV{sup 2} data were taken to perform a Rosenbluth separation to extract the longitudinal and transverse cross sections. The preliminary missing-energy distributions of the forward and backward angle measurements do not indicate an obvious excess of transverse strength.
Date: August 1, 1997
Creator: Ent, R.; Abbott, D. & Dunne, J.
Partner: UNT Libraries Government Documents Department

Proton propagation through nuclei and the quasi-free reaction mechanism studied with (e,e{prime}p) reactions

Description: Jefferson Lab experiment E91-013 measured the energy dependence of proton propagation in nuclei, using the quasi-free (e, e{prime}p) reaction. The ratios of the experimental (e, e{prime}p) cross-sections integrated over the quasi-free region to PWIA calculations are presented as a function of momentum transfer, (0.6 < Q{sup 2} < 3.3 GeV{sup 2}) and target nucleus (C, Fe and Au). As a first step towards a longitudinal and transverse separation of the quasi-free cross-section, a super ratio of the measured to the calculated cross-sections at forward and backward angles is presented.
Date: September 1, 1997
Creator: Dutta, D.; Abbott, D. & Amatuni, T.A.
Partner: UNT Libraries Government Documents Department

Towards a reliable laser spray powder deposition system through process characterization

Description: A series of experiments have been performed to characterize the laser spray powder deposition tea-one (HAZ) in the process. Goal of these experiments was to minimize the heat affected base substrate while obtaining a maximum build-up rate of the deposited material. Response surface models have been developed to achieve this goal. These models indicate that laser irradiance and component travel speed are both important factors to be considered in optimization of this process. These models suggest that a minimum HAZ can be obtained with a maximum material build-up height by maintaining with a slow travel speed. Although these models are useful in identifying significant factor and process trends, further refinement is required for practical use in industrial applications. Weighting of the response variables used in generating the models is being considered to improve the model robustness. High speed imaging of the deposition process suggests that the powder particle size and/or size distribution affects the stability of this process.
Date: July 1, 1995
Creator: Keicher, D.M.; Jellison, J.L.; Schanwald, L.P.; Romero, J.A. & Abbott, D.H.
Partner: UNT Libraries Government Documents Department

The Jefferson Lab Trigger Supervisor System

Description: The authors discuss the design and performance of a Trigger Supervisor System for use in nuclear physics experiments at Jefferson Lab. They also discuss the enhanced features of a new Trigger Supervisor Module now under construction.
Date: June 1, 1999
Creator: Jastrzembski, E.; Abbott, D.J.; Heyes, W.G.; MacLeod, R.W.; Timmer, C. & Wolin, E.
Partner: UNT Libraries Government Documents Department

A High-Performance VME-Based Acquisition System for Positron Emission Mammography

Description: A prototype for a practical and economical breast imaging system for cancer detection is currently under development at Jefferson Lab. The latest advances in bright, fast, crystal scintillators, compact position-sensitive photomultipliers (PSPMT), and high-performance digitizing and readout electronics are being used to develop a compact imager based on Positron Emission Tomography (PET). To facilitate the performance demands of the detector as well as the high number of readout channels, the data acquisition system is built around an intelligent, self-contained, VME form-factor.
Date: November 1, 2001
Creator: Abbott, D.J.; Weisenberger, A.; Majewski, S.; Kieper, D.; Kross, B.; Popov, V. et al.
Partner: UNT Libraries Government Documents Department

Data Distribution Manager

Description: Jefferson Lab produces voluminous amounts of data, currently over 10 MB/sec. We developed a software package designed to manage and distribute all of this data as it is being produced - in real time. Called the Event Transfer (ET) system, it allows users to create data (events) and insert them into the system as well as allow other users to retrieve these events sequentially. The ET system is designed to be easy to use as well as very robust. Although initially implemented in C on Solaris and Linux platforms, we completed a recent port to Java. This paper presents a description of this software package as well as some performance measures.
Date: June 1, 2001
Creator: Timmer, C.; Abbott, D.J.; Gyurjyan, V.H.; Heyes, W.G.; Jastrembski, E. & Wolin, E.
Partner: UNT Libraries Government Documents Department

Fast transfer of shared data

Description: The Event Transfer system enables its users to produce events (data) and share them with other users by utilizing shared memory on either Solaris or Linux-based computers. Its design emphasizes speed, reliability, ease of use, and recoverability from crashes. In addition to fast local operation, the ET system allows network transfer of events. Using multi-threaded code based on POSIX threades and mutexes, a successful implementation was developed which allowed passing events over 500 kHz on a 4 cpu Sun workstation and 150 kHz on a dual cpu PC.
Date: February 1, 2000
Creator: Timmer, C.; Abbott, D.J.; Heyes, W.G.; Jostizembski, E.; MacLeod, R.W. & Wolin, E.
Partner: UNT Libraries Government Documents Department

CODA performance in the real world

Description: The most ambitious implementation of the Jefferson Lab data acquisition system (CODA) to date is for the CLAS spectrometer in Experimental Hall B. CLAS has over 40,000 instrumented channels and uses up to 30 front-end (FASTBUS/VME) crates in the DAQ subsystem. During the initial experiments the authors found that performance of the fully instrumented DAQ system did not scale as expected based on single point to point benchmarks. Over the past year the authors have been able to study various performance bottlenecks in the CLAS DAQ system including front-end real time performance, switched 100BaseT Ethernet data transport, and online data distribution and recording. Performance tuning was necessary for components on both real time (VxWorks) and UNIX (Solaris) operating systems. In addition, a new efficient Event Transfer System (ET) was developed to provide faster online monitoring while having minimal impact on data throughput to storage. They discuss these issues and efforts to overcome the real world problems associated with running a high performance DAQ system on a variety of commercial hardware and software.
Date: June 1, 1999
Creator: Abbott, D.J.; Heyes, W.G.; Jastrzembski, E.; MacLeod, R.W.; Timmer, C. & Wolin, E.
Partner: UNT Libraries Government Documents Department

Experience with certifying borated stainless steel as a shipping cask basket material

Description: The original cask designs for a cask demonstration project featured fuel baskets constructed of borated stainless steel (bss) as a structural material. The project is intended to demonstrate casks that can be used for both shipping and storing spent nuclear fuel assemblies. The baskets were intended to maintain the fuel assemblies in a subcritical array for both normal and accident conditions. The Nuclear Regulatory Commission, however, judged bss to be unacceptable as a structural material. The cask designs were subsequently modified. The knowledge gained during this cask demonstration project may be applicable to development of bss as a basket material in future cask design. 6 refs., 2 figs., 2 tabs.
Date: January 1, 1990
Creator: Abbott, D.G. (EG and G Idaho, Inc., Idaho Falls, ID (USA)) & Nickell, R.E. (Applied Science and Technology, Inc., Poway, CA (USA))
Partner: UNT Libraries Government Documents Department

Deuteron photodisintegration : new results from TJNAF.

Description: The first measurements of the differential cross section from d({gamma},p)n up to 4.0 GeV were performed at the Thomas Jefferson National Accelerator Facility (TJNAF, formerly CEBAF). Bremsstrahlung photons from electron beam impinging on a copper radiator and a liquid deuterium target were employed for this experiment. The experiment was performed in Hall C where the photoprotons at forward angles in the center-of-mass were detected in the High Momentum Spectrometer (HMS) and photoprotons at backward angles were detected in the Short Orbit Spectrometer (SOS). The bremsstrahlung photon energy was reconstructed from the measured proton momentum and angle using the two-body kinematics. We report the cross section results at the proton center-of-mass angles of 37{degree} and 90{degree}. These results are in good agreement with previous lower energy measurements. The 90{degree} data continue to show the constituent-counting-rule behavior up to 4 GeV. The results will be compared with models based on QCD as well as those based on meson-exchange theory.
Date: November 18, 1997
Creator: Abbott, D. J.; Ahmidouch, A.; Armstrong, C. S.; Arrington, J.; Cummings, W. J.; Geesaman, D. F. et al.
Partner: UNT Libraries Government Documents Department

Hyperon-nucleon bound states and electroproduction of strangeness on light nuclei.

Description: The A(e,e{prime}K{sup +})Y X reaction has been investigated in Hall C at Jefferson Lab. Data were taken for Q{sup 2} {approx} 0.35 and 0.5 GeV{sup 2} at a beam energy of 3.245 GeV for {sup 1}H, {sup 2}H, {sup 3}He and {sup 4}He, C and Al targets. The missing mass spectra are fitted with Monte Carlo simulations including {Lambda}, {Sigma}{sup 0}, {Sigma}{sup -} hyperon production. Models for quasifree production are compared to the data, excess yields close to threshold are attributed to FSI. Evidence for {Lambda}-hypernuclear bound states is seen for {sup 3,4}He targets.
Date: June 25, 2002
Creator: Dohrmann, F.; Abbott, D.; Ahmidouch, A.; Ambrozewicz, P.; Armstrong, C. S.; Arrington, J. et al.
Partner: UNT Libraries Government Documents Department

Electroproduction of Kaons on light nuclei.

Description: The A(e,e{prime}K{sup +})YX reaction on H, D, {sup 3}He, and {sup 4}He was investigated in Hall C at CEBAF. Data were obtained for Q{sup 2} {approx} 0.35 and 0.5 GeV{sup 2} at 3.245 GeV. The missing mass spectra for both H and D are fitted with Monte-Carlo simulations incorporating peaks corresponding to {Lambda} production on the proton and {Sigma} production on both the proton and neutron. For D, the cross section ratio {Sigma}{sup 0}/{Sigma}{sup {minus}} {approx} 2, and excess yield close to the thresholds for {Lambda} and {Sigma} production can be attributed to final-state interactions that are compared to the data. The analysis of the data for the He targets is in a more preliminary state with broader quasi-free peaks resulting from the higher Fermi momenta. Evidence for bound {Lambda}-hypernuclear states is seen and other structure may be present.
Date: December 7, 2000
Creator: Zeidman, B.; Abbott, D.; Ahmidouch, A.; Ambrozewicz, P.; Armstrong, C. S.; Arrington, J. et al.
Partner: UNT Libraries Government Documents Department

Electroproduction of strangeness on light nuclei.

Description: The A(e,e{prime} K{sup +})YX reaction has been investigated in Hall C at Jefferson Laboratory for 6 different targets. Data were taken for Q{sup 2} {approx} 0.35 and 0.5 GeV{sup 2} at a beam energy of 3.245 GeV for {sup 1}H, {sup 2}H, {sup 3}He, {sup 4}He, C and Al targets. The missing mass spectra are fitted with Monte Carlo simulations taking into account the production of {Lambda} and {Sigma}{sup 0} hyperon production off the proton, and {Sigma}{sup -} off the neutron. Models for quasifree production are compared to the data, excess yields close to threshold are attributed to FSI. Evidence for {Lambda}-hypernuclear bound states is seen for {sup 3,4}He targets.
Date: May 16, 2002
Creator: Dohrmann, F.; Abbott, D.; Ahmidouch, A.; Ambrozewicz, P.; Armstrong, C. S.; Arrington, J. et al.
Partner: UNT Libraries Government Documents Department