A 2--4 nm Linac Coherent Light Source (LCLS) using the SLAC linac (open access)

A 2--4 nm Linac Coherent Light Source (LCLS) using the SLAC linac

We describe the use of the SLAC linac to drive a unique, powerful. short wavelength Linac Coherent Light Source (LCLS). Operating as an FEL, lasing would be achieved in a single pass of a high peak current electron beam through a long undulator by self-amplified spontaneous emission (SASE). The main components are a high-brightness rf photocathode electron gun; pulse compressors; about 1/5 of the SLAC linac; and a long undulator with a FODO quadrupole focussing system. Using electrons below 8 GeV, the system would operate at wavelengths down to about 3 nm, producing {ge}10 GW peak power in sub-ps pulses. At a 120 Hz rate the average power is {approx} 1 W.
Date: May 1, 1993
Creator: Winick, H.; Bane, K. & Boyce, R.
System: The UNT Digital Library
The 50 MeV Beam Test Facility at LBL (open access)

The 50 MeV Beam Test Facility at LBL

A new beam line, expected to be built by September 1993, will transport the 50 MeV electron beam from the ALS LINAC into an experimental area to support various R&D activities in the Center for Beam Physics at LBL. A variety of experiments are planned involving the interaction of such a relativistic electron beam with plasmas (plasma focusing), laser beams (generation of femtosecond X-ray pulses) and electromagnetic cavities (Crab cavities etc....). The beam line is designed using the measured emittance and Twiss parameters of the ALS linac. It accommodates the different requirements of the various experiments on the electron beam properties (charge, energy, pulse length) and on the handling of the beam before and after the interaction point. Special attention has also been given to incorporate diagnostics for measuring the beam properties (such as the electron energy, bunch length and charge) needed in the interpretation of the experiments.
Date: May 1, 1993
Creator: Leemans, W.; Behrsing, G.; Kim, K. J.; Krupnick, J.; Matuk, C.; Selph, F. et al.
System: The UNT Digital Library
A 600 MeV cyclotron for radioactive beam production (open access)

A 600 MeV cyclotron for radioactive beam production

The magnetic field design for a 600 MeV proton cyclotron is described. The cyclotron has a single stage, a normal conducting magnet coil and a 9.8 m outside yoke diameter. It has 8 sectors, with a transition to 4 sectors in the center region. The magnetic field design was done using 1958 Harwell rectangular ridge system measurements and was compared with recent 3-dimensional field calculations with the program TOSCA at NSCL. The center region 4--8 sector transition focussing was also checked with TOSCA.
Date: May 17, 1993
Creator: Clark, D. J.
System: The UNT Digital Library
Ab initio molecular orbital calculations of molten salt vapor complexes using Gaussian-2 theory: LiAlF{sub 4} and NaAlF{sub 4} (open access)

Ab initio molecular orbital calculations of molten salt vapor complexes using Gaussian-2 theory: LiAlF{sub 4} and NaAlF{sub 4}

The structures and energies of the molten salt vapor complexes LiAlF{sub 4} and NaAlF{sub 4} are studied using new high level ab initio molecular orbital methods. The structures are determined using Moller-Plesset perturbation theory to second-order and the total energies are determined using a recently introduced modification of Gaussian-2 (G2) theory. The total energies are used to determine relative energies of the corner-, edge-, and face-bridged structures and accurate reaction energies. The results are compared to previous theoretical and experimental studies.
Date: May 1993
Creator: Curtiss, L. A.
System: The UNT Digital Library
Accelerator physics analysis with interactive tools (open access)

Accelerator physics analysis with interactive tools

Work is in progress on interactive tools for linear and nonlinear accelerator design, analysis, and simulation using X-based graphics. The BEAMLINE and MXYZPTLK class libraries, were used with an X Windows graphics library to build a program for interactively editing lattices and studying their properties.
Date: May 1, 1993
Creator: Holt, J. A. & Michelotti, L.
System: The UNT Digital Library
Accelerator physics issues at the SSC (open access)

Accelerator physics issues at the SSC

Realization of the design energy and luminosity goals of the Superconducting Super Collider (SSC) will require proper resolutions of a number of challenging problems in accelerator physics. The status of several salient issues in the design of the SSC will be reviewed and updated in this paper. The emphasis will be on the superconducting accelerators.
Date: May 1, 1993
Creator: Dugan, G. F.
System: The UNT Digital Library
Acceptance criteria for reactor coolant pumps and valves (open access)

Acceptance criteria for reactor coolant pumps and valves

Each of the six primary coolant loop systems of the Savannah River Site (SRS) production reactors contains one reactor coolant pump, one PUMP suction side motor operated valve, and other smaller valves. The pumps me double suction, double volute, and radially split type pumps. The valves are different size shutoff and control valves rated from ANSI B16.5 construction class 150 to class 300. The reactor coolant system components, also known as the process water system (PWS), are classified as nuclear Safety Class I components. These components were constructed in the 1950`s in accordance with the then prevailing industry practices. No uniform construction codes were used for design and analysis of these components. However, no pressure boundary failures or bolting failures have ever been recorded throughout their operating history. Over the years, the in-service inspection (ISI) was limited to visual inspection of the pressure boundaries, and surface and volumetric examination of the pressure retaining bolts. Efforts are now underway to implement ISI requirements similar to the ASME Section XI requirements for pumps and valves. This report discusses the new ISI requirements which also call for volumetric examination of the pump casing and valve body welds.
Date: May 1, 1993
Creator: Gupta, N. K.; Miller, R. F. & Sindelar, R. L.
System: The UNT Digital Library
Adaptive cascaded beam-based feedback at the SLC (open access)

Adaptive cascaded beam-based feedback at the SLC

The SLAC Linear Collider now has a total of twenty-four beam-steering feedback loops used to keep the electron and positron beams on their desired trajectories. Seven of these loops measure and control the same beam as it proceeds down the linac through the arcs to the final focus. Ideally each loop should correct only for disturbances that occur between it and the immediate upstream loop. In fact, in the original system each loop corrected for all upstream disturbances. This resulted in undesirable over-correction and ringing. We added MIMO (Multiple Input Multiple Output) adaptive noise cancellers to separate the signal we wish to correct from disturbances further up-stream. This adaptive control improved performance in the 1992 run.
Date: May 1, 1993
Creator: Himel, T.; Allison, S.; Grossberg, P.; Hendrickson, L.; Sass, R. & Shoaee, H.
System: The UNT Digital Library
Adding PCs to SLC Control System (open access)

Adding PCs to SLC Control System

The SLAC Controls Department has interfaced IBM-Compatible PCs to the SLC Control System, for use by the Final Focus Test Beam (FFTB) experimenters, who are building new accelerator equipment and developing and testing it at their home institutions. They will bring the equipment to SLAC and integrate it into the control system using a new software package. The machine physicists and operators will use the existing SLC control system applications and database device types to control and monitor the equipment. The PCs support a limited control environment: they run DOS and exchange messages with the existing control system via TCP/IP over ethernet, using the new SLC Area Message Service. This mechanism will also allow SLC to implement other commercial device controllers that can communicate over ethernet and run the same software interface code.
Date: May 1, 1993
Creator: Lahey, T.; Levitt, S.; MacKenzie, R.; Spencer, N. & Underwood, K.
System: The UNT Digital Library
Addressing the insider threat (open access)

Addressing the insider threat

Computers have come to play a major role in the processing of information vital to our national security. As we grow more dependent on computers, we also become more vulnerable to their misuse. Misuse may be accidental, or may occur deliberately for purposes of personal gain, espionage, terrorism, or revenge. While it is difficult to obtain exact statistics on computer misuse, clearly it is growing. It is also clear that insiders -- authorized system users -- are responsible for most of this increase. Unfortunately, their insider status gives them a greater potential for harm This paper takes an asset-based approach to the insider threat. We begin by characterizing the insider and the threat posed by variously motivated insiders. Next, we characterize the asset of concern: computerized information of strategic or economic value. We discuss four general ways in which computerized information is vulnerable to adversary action by the insider: disclosure, violation of integrity, denial of service, and unauthorized use of resources. We then look at three general remedies for these vulnerabilities. The first is formality of operations, such as training, personnel screening, and configuration management. The second is the institution of automated safeguards, such as single-use passwords, encryption, and biometric …
Date: May 1, 1993
Creator: Hochberg, J. G.; Jackson, K. A.; McClary, J. F. & Simmonds, D. D.
System: The UNT Digital Library
Advanced far infrared detectors (open access)

Advanced far infrared detectors

Recent advances in photoconductive and bolometric semiconductor detectors for wavelength 1 mm > {lambda} > 50 {mu}m are reviewed. Progress in detector performance in this photon energy range has been stimulated by new and stringent requirements for ground based, high altitude and space-borne telescopes for astronomical and astrophysical observations. The paper consists of chapters dealing with the various types of detectors: Be and Ga doped Ge photoconductors, stressed Ge:Ga devices and neutron transmutation doped Ge thermistors. Advances in the understanding of basic detector physics and the introduction of modern semiconductor device technology have led to predictable and reliable fabrication techniques. Integration of detectors into functional arrays has become feasible and is vigorously pursued by groups worldwide.
Date: May 1, 1993
Creator: Haller, E. E.
System: The UNT Digital Library
Advanced oxidation and reduction processes: Closed-loop applications for mixed waste (open access)

Advanced oxidation and reduction processes: Closed-loop applications for mixed waste

At Los Alamos we are engaged in applying innovative oxidation and reduction technologies to the destruction of hazardous organics. Non thermal plasmas and relativistic electron-beams both involve the generation of free radicals and are applicable to a wide variety of mixed waste as closed-loop designs can be easily engineered. Silent discharge plasmas (SDP), long used for the generation of ozone, have been demonstrated in the laboratory to be effective in destroying hazardous organic compounds and offer an altemative to existing post-incineration and off-gas treatments. SDP generates very energetic electrons which efficiently create reactive free radicals, without adding the enthalpy associated with very high gas temperatures. A SDP cell has been used as a second stage to a LANL designed, packed-bed reactor (PBR) and has demonstrated DREs as high as 99.9999% for a variety of combustible liquid and gas-based waste streams containing scintillation fluids, nitrates, PCB surrogates, and both chlorinated and fluorinated solvents. Radiolytic treatment of waste using electron-beams and/or bremsstrahlung can be applied to a wide range of waste media (liquids, sludges, and solids). The efficacy and economy of these systems has been demonstrated for aqueous waste through both laboratory and pilot scale studies. We win present recent experimental and …
Date: May 1, 1993
Creator: Coogan, J. J.; Tennant, R. A.; Rosocha, L. A. & Wantuck, P. J.
System: The UNT Digital Library
Advanced recycling and research complexes: A second strategic use for installations on the base closure list (open access)

Advanced recycling and research complexes: A second strategic use for installations on the base closure list

Obstacles currently facing the solid waste recycling industry are often related to a lack of public and investor confidence, issues of profitability and liability, and insufficient consumer identification with products made from recycled materials. Resolution of these issues may not be possible without major changes in the way the solid waste recycling business is structured. At the same time, we are faced with opportunities which will not likely recur in our lifetimes: access to educated, well trained work forces; and large tracts of land that are contiguous with metropolitan areas and are developed for heavy industry and transportation. Military installations are being converted to civilian use just in time to serve as important a role in our national resource conservation policy. The future of recycling in North America converges with the future of selected bases on the closure list and takes the form of converting these bases into Advanced Recycling and Research Complexes. The premise is simple: use these strategically-located facilities as industrial parks where a broad range of secondary wastes are separated, refined, or converted and made into new products on site. The wastes would include municipal solid waste (MSW), demolition waste, landscape trimmings, used tires, scrap metal, agricultural …
Date: May 1, 1993
Creator: Walter, D. W.; Kuusinen, T. L. & Beck, J. E.
System: The UNT Digital Library
Advances and applications of ABCI (open access)

Advances and applications of ABCI

ABCI (Azimuthal Beam Cavity Interaction) is a computer program which solves the Maxwell equations directly in the time domain when a Gaussian beam goes through an axi-symmetrical structure on or off axis. Many new features have been implemented in the new version of ABCI (presently version 6.6), including the ``moving mesh`` and Napoly`s method of calculation of wake potentials. The mesh is now generated only for the part of the structure inside a window, and moves together with the window frame. This moving mesh option reduces the number of mesh points considerably, and very fine meshes can be used. Napoly`s integration method makes it possible to compute wake potentials in a structure such as a collimator, where parts of the cavity material are at smaller radii than that of the beam pipes, in such a way that the contribution from the beam pipes vanishes. For the monopole wake potential, ABCI can be applied even to structures with unequal beam pipe radii. Furthermore, the radial mesh size can be varied over the structure, permitting to use a fine mesh only where actually needed. With these improvements, the program allows computation of wake fields for structures far too complicated for older codes. …
Date: May 1, 1993
Creator: Chin, Y. H.
System: The UNT Digital Library
Advances in low energy neutral atom imaging techniques (open access)

Advances in low energy neutral atom imaging techniques

Recently proposed low energy neutral atom (LENA) imaging techniques use a collisional process to convert the low energy neutrals into ions before detection. At low energies, collisional processes limit the angular resolution and conversion efficiencies of these devices. However, if the intense ultraviolet light background can be suppressed, direct LENA detection is possible. We present results from a series of experiments designed to develop a novel filtering structure based on free-standing transmission gratings. If the grating period is sufficiently small, free standing transmission gratings can be employed to substantially polarize ultraviolet (UV) light in the wavelength range 300 {Angstrom} to 1500 {Angstrom}. If a second grating is placed behind the first grating with its axis of polarization oriented at a right angle to the first`s, a substantial attenuation of UV radiation is achievable. ne neutrals will pass through the remaining open area of two gratings and be detected without UV background complications. We have obtained nominal 2000 {Angstrom} period (1000 {Angstrom} bars with 1000 {Angstrom} slits) free standing, gold transmission gratings and measured their UV and atomic transmission characteristics. The geometric factor of a LENA imager based on this technology is comparable to that of other proposed LENA imagers. In …
Date: May 1, 1993
Creator: Scime, E. E.; Funsten, H. O.; McComas, D. J.; Moore, K. R. & Gruntman, M.
System: The UNT Digital Library
Advances in the use of tomographic inspection techniques for non-destructive analysis of geometric conductor position and correlation with magnetic cross-section modeling (open access)

Advances in the use of tomographic inspection techniques for non-destructive analysis of geometric conductor position and correlation with magnetic cross-section modeling

Industrial Computerized Tomography has been applied to magnet components in various stages of the manufacturing process. These Computerized Tomographic images can be analyzed to infer detailed dimensional information about magnet component positions (conductor, wedges, collars, etc.) throughout the magnet manufacturing process (cable winding, collaring, yoked/skinned). An analysis technique will be presented and measurement accuracies will be discussed.
Date: May 1, 1993
Creator: Bein, D.; Snitchler, G.; Rabaey, G. F.; Bolger, J.; Crane, R. & Vinson, M.
System: The UNT Digital Library
The ALS Gun Electronics system (open access)

The ALS Gun Electronics system

The ALS Gun Electronics system has been designed to accommodate gun with a custom made socket and high speed electronics circuit which is capable of producing single and multiple electron bunches with time jitters measured at better than 50 PS. The system generates the gated RF signal at ground level before sending it up to the 120 KV-biased gun deck via a fiber optic cable. The current pulse width as a function of grid bias, using an Eimac 8847A planar triode simulating an electron gun, was measured to show the relationship between the two parameters.
Date: May 1, 1993
Creator: Lo, C. C.
System: The UNT Digital Library
The ALS Gun Electronics system (open access)

The ALS Gun Electronics system

The ALS Gun Electronics system has been designed to accommodate gun with a custom made socket and high speed electronics circuit which is capable of producing single and multiple electron bunches with time jitters measured at better than 50 PS. The system generates the gated RF signal at ground level before sending it up to the 120 KV-biased gun deck via a fiber optic cable. The current pulse width as a function of grid bias, using an Eimac 8847A planar triode simulating an electron gun, was measured to show the relationship between the two parameters.
Date: May 1, 1993
Creator: Lo, C. C.
System: The UNT Digital Library
The ALS Storage Ring RF System (open access)

The ALS Storage Ring RF System

The ALS Storage Ring RF System is characterized by the use of the following features: (1) High power loading of two single cell cavities. (2) The use of a tubular ceramic input window employing aperture coupling. (3) The use of waveguide filters and matchers designed for HOM absorption. (4) A comprehensive HOM monitoring system. (5) The use of waveguide water-wedge loads for the magic tee and circulator loads. The results of cavity measurements and high power tests are reported together with the performance of the system during the commissioning and operation phases of the ALS project. Plans for future window development are discussed.
Date: May 1, 1993
Creator: Taylor, B.; Lo, C. C.; Baptiste, K.; Guigli, J. & Julian, J.
System: The UNT Digital Library
Analysis of the ITER H-mode confinement database (open access)

Analysis of the ITER H-mode confinement database

In order to predict the global energy confinement time in the next generation of large tokamaks it is essential to have data from machines of different sizes and operating parameter regimes. This data can also be used to construct dimensionless scalings and thereby attempt to differentiate between Bohm and gyro-Bohm based transport models. Previously, at the request of the ITER project, H-mode global confinement data was assembled from six machines ASDEX, DIII-D, JET, JFT-2M, PBX-M, and PDX into a single database. This collaboration has continued with the initial database being expanded by extending the plasma parameter space as well as by improving the precision of some of the relevant calculated plasma parameters. This paper summarizes work that has been performed on the newest version (ITERH.DB2) of the confinement database.
Date: May 1, 1993
Creator: Schissel, D. P.; Kardaun, O. J. W. F.; Ryter, F. & Stroth, U.
System: The UNT Digital Library
Anatomy of a control system; a system designer`s view (open access)

Anatomy of a control system; a system designer`s view

The Advanced Light Source (ALS) control system is quite unconventional in its design and implementation. This paper discusses the system design considerations, the actual implementation, hardware and software costs, and the measured performance across all layers of the system.
Date: May 1, 1993
Creator: Magyary, S.
System: The UNT Digital Library
Angular resolution studies of the CYGNUS array using the shadows of the sun and moon (open access)

Angular resolution studies of the CYGNUS array using the shadows of the sun and moon

Using the cosmic ray shadows of the sun and moon, we have estimated the angular resolution of the CYGNUS extensive air shower array. With the event sample now available we estimate the angular resolution of the array to be 0.70{sub {minus}0.06}{sup {plus}0.07} degrees. The resolution depends on the total number of detected shower particles. A new parameterization of the measured shower-front timing structure and the use of counters with small pulse areas lead to a {approximately}25% improvement in the resolution. The systematic pointing error of the array is less than 0.4{degree}.
Date: May 1, 1993
Creator: Shoup, A. L. & Collaboration, The CYGNUS
System: The UNT Digital Library
The appearance of beam lines (open access)

The appearance of beam lines

The combination of an existing graphics package with a large program like TRANSPORT has often resulted in considerable modification to the large program. Use of other graphics package has resulted in essentially having to repeat the work. This difficulty has been avoided in a modification of TRANSPORT which produce layouts of beam lines. Drawings of the reference trajectory and three-dimensional images of all magnets are made by the graphics package TOP DRAWER. Nothing specific to TOP DRAWER or any other graphics has been incorporated into TRANSPORT. If a user is with a different graphics package he or she can then begin usage of this alternate package essentially immediately.
Date: May 1, 1993
Creator: Carey, D. C.
System: The UNT Digital Library
The appearance of beam lines (open access)

The appearance of beam lines

The combination of an existing graphics package with a large program like TRANSPORT has often resulted in considerable modification to the large program. Use of other graphics package has resulted in essentially having to repeat the work. This difficulty has been avoided in a modification of TRANSPORT which produce layouts of beam lines. Drawings of the reference trajectory and three-dimensional images of all magnets are made by the graphics package TOP DRAWER. Nothing specific to TOP DRAWER or any other graphics has been incorporated into TRANSPORT. If a user is with a different graphics package he or she can then begin usage of this alternate package essentially immediately.
Date: May 1, 1993
Creator: Carey, D.C.
System: The UNT Digital Library