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On bunch lengthening using the fourth harmonic cavity in the NSLS VUV ring

Description: It has been suggested that the phase of the beam excited voltage in the harmonic cavity can be controlled by detuning its resonant frequency from the beam current harmonic. Unfortunately the detuning needed to flatten the acceleration waveform also corresponds to the region of Robinson instability for the harmonic cavity. Therefore, lengthening the bunch may be followed by large amplitude synchrotron oscillation of the bunch center of mass. Bunch lengthening is discussed in this note from several points of view. There follows a simple review of single electron oscillations in a quartic potential. Then equations are developed for the coupled oscillations of a cavity and a rigid bunch as a fully nonlinear, time dependent initial value problem. Next, a computer program that solves these equations for one, two or more cavities, with and without externally driven fields, is described and some simulations of the harmonic cavity interaction are shown. Finally, the fully nonlinear equations are linearized to derive a dispersion relation for the case of beam excitation in the harmonic cavity. 6 refs., 5 figs.
Date: February 1, 1988
Creator: Wachtel, J.M.
Partner: UNT Libraries Government Documents Department

Computation of emittance growth in a focusing wiggler FEL (Free Electron Laser)

Description: Computed electron trajectories in a free electron laser show significant emittance growth in the wiggle plane when there are wiggler field gradients. For a low gain free electron laser using a focusing planar wiggler, phase space plots show the development of this 3-dimensional effect as well as rotation of the phase space region occupied by the beam due to betatron oscillations in the focusing wiggler field. Matching the input electron beam to the wiggler eliminates emittance growth. 3 refs., 5 figs., 1 tab.
Date: January 1, 1988
Creator: Ben-Zvi, I. & Wachtel, J.M.
Partner: UNT Libraries Government Documents Department

Validating cognitive support for operators of complex human-machine systems

Description: Modem nuclear power plants (NPPs) are complex systems whose performance is the result of an intricate interaction of human and system control. A complex system may be defined as one which supports a dynamic process involving a large number of elements that interact in many different ways. Safety is addressed through defense-in-depth design and preplanning; i.e., designers consider the types of failures that are most likely to occur and those of high consequence, and design their solutions in advance. However, complex interactions and their failure modes cannot always be anticipated by the designer and may be unfamiliar to plant personnel. These situations may pose cognitive demands on plant personnel, both individually and as a crew. Other factors may contribute to the cognitive challenges of NPP operation as well, including hierarchal processes, dynamic pace, system redundancy and reliability, and conflicting objectives. These factors are discussed in this paper.
Date: October 1995
Creator: O`Hara, J. & Wachtel, J.
Partner: UNT Libraries Government Documents Department

Rf stability, control and bunch lengthening in electron synchrotron storage rings

Description: A self-consistent theory for nonlinear longitudinal particle motion and rf cavity excitation in a high energy electron storage ring is developed. Coupled first order equations for the motion of an arbitrary number of particles and for the field in several rf cavities are given in the form used in control system theory. Stochastic quantum excitation of synchrotron motion is included, as are the effects of rf control system corrections. Results of computations for double cavity bunch lengthening are given. 11 refs., 4 figs., 1 tab.
Date: September 1, 1989
Creator: Wachtel, J.M.
Partner: UNT Libraries Government Documents Department

Advanced alarm systems: Display and processing issues

Description: This paper describes a research program sponsored by the US Nuclear Regulatory Commission to address the human factors engineering (HFE) deficiencies associated with nuclear power plant alarm systems. The overall objective of the study is to develop HFE review guidance for alarm systems. In support of this objective, human performance issues needing additional research were identified. Among the important issues were alarm processing strategies and alarm display techniques. This paper will discuss these issues and briefly describe our current research plan to address them.
Date: May 1, 1995
Creator: O`Hara, J.M.; Wachtel, J. & Perensky, J.
Partner: UNT Libraries Government Documents Department

Methodological issues in the validation of complex human-machine systems

Description: Integrated system validation is one aspect of the US Nuclear Regulatory Commission`s design review process for human-system interfaces. This paper will consider three methodological issues that must be addressed in validation and their implications for drawing conclusions about the acceptability of the integrated system. They are: representing the integrated system, representing the operational events it must handle, and representing system performance. A logical basis for generalizability from validation tests to predicted performance of the integrated system emerges from the comparability of the psychological and physical processes of the test and actual situations. Generalizability of results is supported when the integrated system, operating conditions and performance are representative of their real-world counterparts. The methodological considerations for establishing representativeness are discussed.
Date: May 1, 1995
Creator: O`Hara, J.; Stubler, W. & Wachtel, J.
Partner: UNT Libraries Government Documents Department

Optics of beam transport in the NSLS uv-FEL

Description: The NSLS-FEL is designed as a single pass FEL to generate radiation 1 mJ per pulse (10 psec) in 10{sup {minus}4} bandwidth, with continuously tunable wavelength in the range 100--300 nm. A superconducting, recirculating linac provides electron beams of energy 20 MeV to 260 MeV at 4{pi} mm mrad normalized rms emittance with less than 0.1% momentum spread and 2 mm rms bunch length. The optics in this machine is seriously restricted by the requirement to not degrade the electron beam quality. We present a lattice design for the transport lines to be used in beam injection, linac focussing and recirculations. These beam lines are tuned to be linearly achromatic and isochronous, to avoid beam breakup in the cavities, and to minimize second order distortions of the emittance. Special transport lines are designed that allow rapid switching of the electron beam to drive two different FEL wigglers. This provides the capability for up to four simultaneous, high power, independently energy tuned laser beam.
Date: January 1, 1992
Creator: Zhang, X.; Kramer, S.L. & Wachtel, J.
Partner: UNT Libraries Government Documents Department

The importance of simulation facilities for the development of review criteria for advanced human system interfaces

Description: Advanced control room (ACR) concepts are being developed in the commercial nuclear industry as part of future reactor designs. The ACRs will use advanced human-system interface (HSI) technologies that may have significant implications for plant safety in that they will affect the operator`s overall role (function) in the system, the method of information presentation, the ways in which the operator interacts with the system, and the requirements on the operator to understand and supervise an increasingly complex system. The U.S. Nuclear Regulatory Commission (NRC) reviews the HSI aspects of control rooms to ensure that they are designed to good human factors engineering principles and that operator performance and reliability are appropriately supported to protect public health and safety. The NRC is developing guidelines to support their review of these advanced designs. As part of this effort, a methodology for guidance development was established, and topics in need of further research were identified. Simulators of various kinds are likely to play important roles in the development of review guidelines and in the evaluation of ACRs. This paper describes a general approach to review criteria development, and discusses the role of simulators in addressing research needs.
Date: April 1, 1994
Creator: O`Hara, J. M. & Wachtel, J.
Partner: UNT Libraries Government Documents Department

Experimental validation of navigation workload metrics

Description: Advanced digital computer display interfaces in the control room may increase operator workload. Workstation monitors provide limited display area, and information is represented in large-scale display networks. Display navigation may generate disorienting effects, require additional resources for window management, and increase memory and data integration requirements. Six ORNL employees participated in an experiment to validate proposed metrics of navigation workload in the advanced control room. The task environment was a display network consisting of 25 windows resembling a simplified Safety Parameter Display System for Pressurized Water Reactors. A repeated measures design with 3 within subjects factors was employed. The factors were task difficulty, navigation distance level, and a blocking factor. Participants were asked to monitor a single parameter or two parameters. Fourteen candidate metrics were tested. Analysis of variance of the modified task load index (MTLX) and rating subscales demonstrated substantial support for the claim that navigation of large-scale display networks can impose additional mental load. Primary and secondary task performance measures exhibited ceiling effects. Memory probes for these tasks were inadequate because they were recognition-based and coarse. Eye gaze measures were not validated, indicating a need for more refined data reduction algorithms. Strong positive correlations were found between MTLX and both navigation duration and standard deviation of pupil diameter. Further study and increased statistical power are required to validate objective navigation workload metrics.
Date: April 1, 1994
Creator: Schryver, J. C. & Wachtel, J. A.
Partner: UNT Libraries Government Documents Department

Optics of beam transport in the NSLS uv-FEL

Description: The NSLS-FEL is designed as a single pass FEL to generate radiation 1 mJ per pulse (10 psec) in 10{sup {minus}4} bandwidth, with continuously tunable wavelength in the range 100--300 nm. A superconducting, recirculating linac provides electron beams of energy 20 MeV to 260 MeV at 4{pi} mm mrad normalized rms emittance with less than 0.1% momentum spread and 2 mm rms bunch length. The optics in this machine is seriously restricted by the requirement to not degrade the electron beam quality. We present a lattice design for the transport lines to be used in beam injection, linac focussing and recirculations. These beam lines are tuned to be linearly achromatic and isochronous, to avoid beam breakup in the cavities, and to minimize second order distortions of the emittance. Special transport lines are designed that allow rapid switching of the electron beam to drive two different FEL wigglers. This provides the capability for up to four simultaneous, high power, independently energy tuned laser beam.
Date: June 1, 1992
Creator: Zhang, X.; Kramer, S. L. & Wachtel, J.
Partner: UNT Libraries Government Documents Department

Local control stations

Description: This paper describes research concerning the effects of human engineering design at local control stations (i.e., operator interfaces located outside the control room) on human performance and plant safety. The research considered both multifunction panels (e.g. remote shutdown panels) as well as single-function interfaces (e.g., valves, breakers, gauges, etc.). Changes in performance shaping factors associated with variations in human engineering at LCSs were estimated based on expert opinion. By means of a scaling procedure, these estimates were used to modify the human error probabilities in a PRA model, which was then employed to generate estimates of plant risk and scoping-level value/impact ratios for various human engineering upgrades. Recent documentation of human engineering deficiencies at single-function LCSs was also reviewed, and an assessment of the current status of LCSs with respect to human engineering was conducted.
Date: May 1, 1993
Creator: Brown, W. S.; Higgins, J. C. & Wachtel, J. A.
Partner: UNT Libraries Government Documents Department

The development and evaluation of guidelines for the review of advanced human-system interfaces

Description: Advanced control rooms for future nuclear power plants are being designed utilizing computer-based technologies. The US Nuclear Regulatory Commission reviews the human engineering aspects of such control rooms to ensure that they are designed to good human factors engineering principles and that operator performance and reliability are appropriately supported in order to protect public health and safety. This paper describes a general approach to advanced human-system interface review, development of human factors guidelines to support NRC safety reviews of advanced systems, and the results of a guideline test and evaluation program.
Date: December 31, 1992
Creator: O`Hara, J. M. & Wachtel, J.
Partner: UNT Libraries Government Documents Department

Development of comprehensive HFE guidelines for the evaluation of NPP human systems interfaces

Description: Advanced control room (ACR) concepts are being developed in the commercial nuclear power industry as part of future reactor designs. The ACRs will use advanced human-system interface (HSI) technologies that may have significant implications for plant safety in that they will affect the ways in which the operator interacts with and supervises an increasingly complex system. The US Nuclear Regulatory Commission (NRC) reviews the HSI aspects of control rooms to ensure that they are designed to good human factors engineering principles and that operator performance and reliability are appropriately supported to protect public health and safety. The NRC is developing guidelines to support its review of these advanced designs. This paper discusses (1) the development of guidelines for advanced HSI review, (2) the integration of those guidelines with existing guidance, and (3) a methodology for further guidance development.
Date: October 1, 1994
Creator: O`Hara, J. M.; Brown, W. S. & Wachtel, J.
Partner: UNT Libraries Government Documents Department

The use of simulation in the development of human factors guidelines for alarm systems

Description: This paper describes a research program sponsored by the US Nuclear Regulatory Commission to address the human factors engineering (HFE) aspects of nuclear power plant alarm systems. The overall objective of the program is to develop HFE review guidance for advanced alarm systems. As part of this program, guidance was developed based on a broad review and analysis of technical and research literature. In the course of guidance development, aspects of alarm system design for which the technical basis was insufficient to support guidance developed were identified. Experimental research is currently underway to address the highest priority topics: alarm processing and display characteristics. This paper provides an overview of the approach to guidance development and discusses the role of simulation in the development approach. Finally, the current simulator-based experiment is described to illustrate how the alarm system design features are being studied.
Date: July 1, 1997
Creator: O`Hara, J.; Brown, W.S.; Hallbert, B.; Skraaning, G.; Wachtel, J. & Persensky, J.
Partner: UNT Libraries Government Documents Department

HUMAN FACTORS GUIDANCE FOR CONTROL ROOM EVALUATION

Description: The Human-System Interface Design Review Guideline (NUREG-0700, Revision 1) was developed by the US Nuclear Regulatory Commission (NRC) to provide human factors guidance as a basis for the review of advanced human-system interface technologies. The guidance consists of three components: design review procedures, human factors engineering guidelines, and a software application to provide design review support called the ``Design Review Guideline.'' Since it was published in June 1996, Rev. 1 to NUREG-0700 has been used successfully by NRC staff, contractors and nuclear industry organizations, as well as by interested organizations outside the nuclear industry. The NRC has committed to the periodic update and improvement of the guidance to ensure that it remains a state-of-the-art design evaluation tool in the face of emerging and rapidly changing technology. This paper addresses the current research to update of NUREG-0700 based on the substantial work that has taken place since the publication of Revision 1.
Date: July 30, 2000
Creator: OHARA,J.; BROWN,W.; STUBLER,W.; HIGGINS,J.; WACHTEL,J. & PERSENSKY,J.J.
Partner: UNT Libraries Government Documents Department

Advanced control room evaluation: General approach and rationale

Description: Advanced control rooms (ACRs) for future nuclear power plants (NPPs) are being designed utilizing computer-based technologies. The US Nuclear Regulatory Commission reviews the human engineering aspects of such control rooms to ensure that they are designed to good human factors engineering principles and that operator performance and reliability are appropriately supported in order to protect public health and safety. This paper describes the rationale and general approach to the development of a human factors review guideline for ACRs. The factors influencing the guideline development are discussed, including the review environment, the types of advanced technologies being addressed, the human factors issues associated with advanced technology, and the current state-of-the-art of human factors guidelines for advanced human-system interfaces (HSIs). The proposed approach to ACR review would track the design and implementation process through the application of review guidelines reflecting four review modules: planning, design process analysis, human factors engineering review, and dynamic performance evaluation. 21 refs.
Date: January 1, 1991
Creator: O'Hara, J.M. (Brookhaven National Lab., Upton, NY (USA)) & Wachtel, J. (Nuclear Regulatory Commission, Washington, DC (USA))
Partner: UNT Libraries Government Documents Department

Proposed uv-FEL user facility at BNL

Description: The NSLS at Brookhaven National Laboratory is proposing the construction of a UV-FEL operating in the wavelength range from visible to 750{Angstrom}. Nano-Coulomb electron pulses will be generated at a laser photo-cathode RF gun at a repetition rate of 10 KHz. The 6 ps pulses will be accelerated to 250 MeV in a superconducting linac. The FEL output will serve four stations with independent wavelength tuning, using two wigglers and two rotating mirror beam switches. Seed radiation for the FEL amplifiers will be provided by conventional tunable lasers, and the final frequency multiplication from the visible or near UV to the VUV will be carried out in the FEL itself. Each FEL will comprise of an initial wiggler resonant to the seed wavelength, a dispersion section, and a second wiggler resonant to the output wavelength. The facility will provide pump probe capability, FEL or FEL, and FEL on synchrotron light from an insersion device on the NSLS X-Ray ring. 15 refs., 2 figs., 3 tabs.
Date: January 1, 1991
Creator: Ben-Zvi, I.; Di Mauro, L.F.; Krinsky, S.; White, M.G.; Yu, L.H.; Batchelor, K. et al.
Partner: UNT Libraries Government Documents Department