Design of a continuous duty cryopump (open access)

Design of a continuous duty cryopump

A continuous duty cryopump system was designed and developed that comprises a self-contained cryopump for installation into a vacuum chamber, and a microprocessor controller for automatic operation. This deuterium pump has two units in a single housing, arranged so that one is pumping while the other is being regenerated. Liquid helium-cooled, finned sections in each unit pump deuterium by condensation, and a third pump integral within the cryopump housing collects the regenerated gas. A microprocessor unit controls distribution of liquid and gaseous helium, used for conditioning the pumping units, and operates remote actuators for the regeneration. Software provides fully automatic, timed sequencing of the repetitive cryopump events which include: cooldown of the pumping units, opening of the louvers isolating the unit from the vacuum chamber, closing of the louvers, and warming up of the unit for regeneration. Default values in the software can be reprogrammed by the operator through the keyboard in response to prompts displayed on the computer. An override allows the operator to control the cryopump manually by activating switches on a control panel. Interlocks to prevent cryogen lockup are included in the software.
Date: May 1, 1985
Creator: Sedgley, D.W.
Object Type: Report
System: The UNT Digital Library
Evaluation of the gas production economics of the gas hydrate cyclic thermal injection model. [Cyclic thermal injection] (open access)

Evaluation of the gas production economics of the gas hydrate cyclic thermal injection model. [Cyclic thermal injection]

The objective of the work performed under this directive is to assess whether gas hydrates could potentially be technically and economically recoverable. The technical potential and economics of recovering gas from a representative hydrate reservoir will be established using the cyclic thermal injection model, HYDMOD, appropriately modified for this effort, integrated with economics model for gas production on the North Slope of Alaska, and in the deep offshore Atlantic. The results from this effort are presented in this document. In Section 1, the engineering cost and financial analysis model used in performing the economic analysis of gas production from hydrates -- the Hydrates Gas Economics Model (HGEM) -- is described. Section 2 contains a users guide for HGEM. In Section 3, a preliminary economic assessment of the gas production economics of the gas hydrate cyclic thermal injection model is presented. Section 4 contains a summary critique of existing hydrate gas recovery models. Finally, Section 5 summarizes the model modification made to HYDMOD, the cyclic thermal injection model for hydrate gas recovery, in order to perform this analysis.
Date: May 1, 1985
Creator: Kuuskraa, V.A.; Hammersheimb, E. & Sawyer, W.
Object Type: Report
System: The UNT Digital Library
Control of indoor radon and radon progeny concentrations (open access)

Control of indoor radon and radon progeny concentrations

There are three general categories of techniques for the control of radon and radon progeny concentrations in indoor air - restriction of radon entry, reduction of indoor radon concentrations by ventilation or air cleaning, and removal of airborne radon progeny. The predominant radon entry process in most residences appears to be pressure driven flow of soil gas through cracks or other openings in the basement, slab, or subfloor. Sealing these openings or ventilation of the subslab or subfloor space are methods of reducing radon entry rates. Indoor radon concentrations may be reduced by increased ventilation. The use of charcoal filters for removal of radon gas in the indoor air by adsorption has also been proposed. Concentrations of radon progeny, which are responsible for most of the health risks associated with radon exposures, can be controlled by use of electrostatic or mechanical filtration. Air circulation can also reduce radon progeny concentrations in certain cases. This paper reviews the application and limitations of each of these control measures and discusses recent experimental results.
Date: May 1, 1985
Creator: Sextro, R.G.
Object Type: Article
System: The UNT Digital Library
New rf power system for SuperHILAC (open access)

New rf power system for SuperHILAC

The upgraded rf system for the SuperHILAC is now operational using 9 new tetrode amplifiers. Each amplifier can produce in excess of 1MW of 70 Mhz pulsed rf power. Ferrite is used to decouple the screen grid circuit and to absorb parasitic oscillations. This results in a very stable amplifier with reasonable gain. This system uses a common 8 MW anode power supply and crowbar system. Overall system efficiency has been increased significantly. We project a 3 year payback on the equipment cost, realized from the power savings alone. 2 refs., 5 figs.
Date: May 1, 1985
Creator: Fugitt, J.; Lancaster, H. & Sorensen, R.
Object Type: Article
System: The UNT Digital Library
High current beam transport with multiple beam arrays (open access)

High current beam transport with multiple beam arrays

Highlights of recent experimental and theoretical research progress on the high current beam transport of single and multiple beams by the Heavy Ion Fusion Accelerator Research (HIFAR) group at the Lawrence Berkeley Laboratory (LBL) are presented. In the single beam transport experiment (SBTE), stability boundaries and the emittance growth of a space charge dominated beam in a long quadrupole transport channel were measured and compared with theory and computer simulations. Also, a multiple beam ion induction linac (MBE-4) is being constructed at LBL which will permit study of multiple beam transport arrays, and acceleration and bunch length compression of individually focused beamlets. Various design considerations of MBE-4 regarding scaling laws, nonlinear effects, misalignments, and transverse and longitudinal space charge effects are summarized. Some aspects of longitudinal beam dynamics including schemes to generate the accelerating voltage waveforms and to amplify beam current are also discussed.
Date: May 1, 1985
Creator: Kim, C.H.
Object Type: Article
System: The UNT Digital Library
Lattice and bypass design for a coherent xuv facility (open access)

Lattice and bypass design for a coherent xuv facility

The design of a magnet lattice and bypass for a coherent radiation facility is discussed. The lattice is the missing magnet FODO structure first proposed by Vignola for a 6 GeV light source. This has been adapted for a 750-1300 MeV electron storage ring for use with both conventional insertion devices and a high gain FEL optimized for output at 400 A. The latter device requires that the electron bunch be deflected into a small aperture bypass, then reinjected into the ring where the perturbing effects of the FEL are damped out. 8 refs., 7 figs.
Date: May 1, 1985
Creator: Jackson, A.; Garren, A.A. & Vignola, G.
Object Type: Article
System: The UNT Digital Library
Metal vapor vacuum arc (MEVVA) high current ion source (open access)

Metal vapor vacuum arc (MEVVA) high current ion source

An ion source is described in which a metal vapor vacuum arc is used to create the plasma from which the ions are extracted. Beams of a variety of ions have been produced, ranging from lithium up to uranium. At an extraction voltage of 25 kV we've measured an ion beam current of over 1 Ampere, with over 550 ema of the beam in an emittance of 0.07..pi.. cm. mradians (normalized). The ion charge state distribution varies with cathode material and with arc power; for uranium a typical distribution is peaked at U/sup 5 +/, with up to 40% of the beam current in this charge state. 27 refs., 10 figs.
Date: May 1, 1985
Creator: Brown, I.G.
Object Type: Article
System: The UNT Digital Library
Difficulties with inferring neutron cross sections from charged-particle reactions (open access)

Difficulties with inferring neutron cross sections from charged-particle reactions

We have investigated problems associated with inferring cross sections for neutron reactions on unstable nuclei in the mass-90 region from charged-particle reactions on nearby stable targets. We conclude that effects due to precompound evaporation, isospin, and multiple reaction paths severely limit the circumstances under which charged-particle studies may be directly and easily converted to neutron cross sections of useful accuracy. 4 refs., 2 figs.
Date: May 7, 1985
Creator: Gardner, D. G. & Gardner, M. A.
Object Type: Article
System: The UNT Digital Library
Compact heavy ion RFQ preaccelerator for use at the CERN Linac I (open access)

Compact heavy ion RFQ preaccelerator for use at the CERN Linac I

This paper describes the LBL contribution to a project designed to provide fully-stripped oxygen beams for acceleration in the CERN PS complex. A preaccelerator for Linac I, consisting of an ECR ion source, an RFQ linac, and rf matching cavities, is being assembled as part of a collaborative arrangement among LBL, GSI, and CERN. The RFQ, designed and built at LBL, will accept analyzed oxygen +6 beam from the ECR at 5.6 keV/amu, and accelerate it to 139.5 keV/amu, the injection energy required for 2 ..beta..lambda operation of Linac I. Stripping to +8 will be done with a foil stripper at 12.5 MeV/amu at the exit of Linac I. The RFQ operates at 202.56 MHz and is 0.86 meters in length. The structure is stabilized with vane coupling rings, and uses a single drive loop and a single tuning loop. 5 refs., 3 figs.
Date: May 1, 1985
Creator: Gough, R.A.; Staples, J.; Caylor, R.; Howard, D.; MacGill, R. & Tanabe, J.
Object Type: Article
System: The UNT Digital Library
LBL neutralized beam focusing experiment (open access)

LBL neutralized beam focusing experiment

An intense neutralized Cs/sup +1/ beam has been focused by an electrostatic polarization field induced by a solenoidal magnetic field of 10-25 gauss. This report describes the experiment and compares the results with the predictions of an analytic linearized fluid model and a particle-in-cell simulation which treats the motion of the warm electrons in detail.
Date: May 1, 1985
Creator: Krafft, G. A.; Kim, C. H. & Smith, L.
Object Type: Article
System: The UNT Digital Library
Search for new effects in e/sup +/e/sup -/ interactions (open access)

Search for new effects in e/sup +/e/sup -/ interactions

Recent measurements of R, the ratio of the total hadron cross section to the lowest order muon pair cross section, are discussed which have systematic overall scale errors on the absolute value of R of 7% or less. Experiments are reviewed that have sought exotic effects in e/sup +/e/sup -/ at the highest available energies. The search for narrow states in the radiative decays of the J/psi and UPSILON are also reviewed. 35 refs., 24 figs. (LEW)
Date: May 1, 1985
Creator: Bloom, E.D.
Object Type: Article
System: The UNT Digital Library
Application of a dc SQUID to rf Amplification: NQR (open access)

Application of a dc SQUID to rf Amplification: NQR

Superconducting QUantum Interference Devices (SQUIDs) have been used for more than a decade for the detection of magnetic resonance. Until recently, these devices had mostly been confined to operation in the audiofrequency range, so that experiments have been restricted to measurements of resonance at low frequencies, or of changes in the static susceptibility of a sample induced by rf irradiation at the resonant frequency. However, the recent extension of the operating range of low noise dc SQUIDs to radiofrequencies (rf) allows one to detect magnetic resonance directly at frequencies up to several hundred megahertz. In this paper, we begin by summarizing the properties of dc SQUIDs as tuned rf amplifers. We then describe first, the development of a SQUID system for the detection of pulsed nuclear quadrupole resonance (NQR) at about 30 MHz and second, a novel technique for observing magnetic resonances in the absence of any externally applied rf fields.
Date: May 1, 1985
Creator: Hilbert, C.; Clarke, J.; Sleator, T. & Hahn, E. L.
Object Type: Article
System: The UNT Digital Library
Analytical methods of electrode design for a relativistic electron gun (open access)

Analytical methods of electrode design for a relativistic electron gun

The standard paraxial ray equation method for the design of electrodes for an electrostatically focused gun is extended to include relativistic effects and the effects of the beam's azimuthal magnetic field. Solutions for parallel and converging beams are obtained and the predicted currents are compared against those measured on the High Brightness Test Stand. 4 refs., 2 figs.
Date: May 9, 1985
Creator: Caporaso, G.J.; Cole, A.G. & Boyd, J.K.
Object Type: Article
System: The UNT Digital Library
Nu shifts in betatron oscillations from uniform perturbations in the presence of non-linear magnetic guide fields (open access)

Nu shifts in betatron oscillations from uniform perturbations in the presence of non-linear magnetic guide fields

Uniform magnetic field perturbations cause a closed orbit distortion in a circular accelerator. If the magnetic guide field is non-linear these perturbations can also cause a Nu shift in the betatron oscillations. Such a shift in radial Nu values has been observed in the Bevalac while studying the low energy resonant extraction system. In the Bevalac, the radial perturbation comes from the quadrants being magnetically about 0.8% longer than 90/sup 0/. The normal effect of this type of perturbation is a radial closed orbit shift and orbit distortion. The Nu shift, associated with this type of perturbation in the presence of a non-linear guide field, is discussed in this paper. A method of handling the non-linear n values is discussed as well as the mechanism for the associated Nu shift. Computer calculations are compared to measurements. 2 refs., 4 figs.
Date: May 1, 1985
Creator: Crebbin, K. C.
Object Type: Article
System: The UNT Digital Library
Effect of focusing field nonlinearities in MBE-4 on transverse beam dynamics (open access)

Effect of focusing field nonlinearities in MBE-4 on transverse beam dynamics

A particle simulation code was used to study the effect on transverse beam dynamics of nonlinearities of the focusing field in a linear accelerator transporting a multiple beam array. Nonlinear field strengths for various multiple-beam design geometries were calculated by relaxation codes for use in the simulation calculation. Nonlinearities due to asymmetry of the electrode array with respect to a single beam were found to be negligible. Electrode end effect nonlinearities led to emittance growth for off-axis beams, though for the geometry of MBE-4, this was negligible. For misaligned beams, a dodecapole field caused significant emittance growth. This was not seen in single particle tracking calculations. Fields due to induced charge on the electrodes can reduce this effect, or the dodecapole field can be eliminated by proper choice of the electrode radius.
Date: May 1, 1985
Creator: Celata, C. M.; Brady, V. O.; Laslett, L. J.; Smith, L. & Haber, I.
Object Type: Article
System: The UNT Digital Library
Limits on likesign dilepton production in nu/sub. mu. / interactions (open access)

Limits on likesign dilepton production in nu/sub. mu. / interactions

We have searched for the production of likesign dilepton events (nu/sub ..mu../ + Ne ..-->.. ..mu../sup -/ + e/sup -/ + ...) in a wideband neutrino beam at FNAL using the 15' bubble chamber. We observe no signal above the background arising from conventional sources. We set 90% confidence level upper limits for the production rates of (nu/sub ..mu../ + Ne ..-->.. ..mu../sup -/ + e/sup -/ + ...)/(nu/sub ..mu../ + Ne ..-->.. ..mu../sup -/ + ...) less than or equal to 8 * 10/sup -5/ and (nu/sub ..mu../ + Ne ..-->.. ..mu../sup -/ + e/sup -/ + ...)/(nu/sub ..mu../ + Ne ..-->.. ..mu../sup -/ + e/sup +/ + ...) less than or equal to 6 * 10/sup -2/.
Date: May 21, 1985
Creator: Baker, N. J.; Connolly, P. L.; Kahn, S. A.; Murtagh, M. J.; Palmer, R. B.; Samios, N. P. et al.
Object Type: Article
System: The UNT Digital Library
Mirror Fusion Test Facility-B (MFTF-B) axicell configuration: NbTi magnet system. Manufacturing/producibility final report. Volume 2 (open access)

Mirror Fusion Test Facility-B (MFTF-B) axicell configuration: NbTi magnet system. Manufacturing/producibility final report. Volume 2

This Final MFTF-B Manufacturing/Producibility Report covers facilities, tooling plan, manufacturing sequence, schedule and performance, producibility, and lessons learned for the solenoid, axicell, and transition coils, as well as a deactivation plan, conclusions, references, and appendices.
Date: May 1, 1985
Creator: Ritschel, A.J. & White, W.L.
Object Type: Report
System: The UNT Digital Library
High temperature experiment for accelerator inertial fusion (open access)

High temperature experiment for accelerator inertial fusion

The High Temperature Experiment (HTE) is intended to produce temperatures of 50 to 100 eV in solid density targets driven by heavy ion beams from a multiple beam induction linac. The fundamental variables (particle species, energy, number of beamlets, current and pulse length) must be fixed to achieve the temperature at minimum cost, subject to criteria of technical feasibility and relevance to the development of a Fusion Driver. The conceptual design begins with an assumed (radiation-limited) target temperature and uses limitations due to particle range, beamlet perveance, and target disassembly to bound the allowable values of mass number (A) and energy (E). An accelerator model is then applied to determine the minimum length accelerator, which is a guide to total cost. The accelerator model takes into account limits on transportable charge, maximum gradient, core mass per linear meter, and head-to-tail momentum variation within a pulse.
Date: May 1, 1985
Creator: Lee, Edward P.
Object Type: Article
System: The UNT Digital Library
Classical geometrical interpretation of ghost fields and anomalies in Yang-Mills theory and quantum gravity (open access)

Classical geometrical interpretation of ghost fields and anomalies in Yang-Mills theory and quantum gravity

The reinterpretation of the BRS equations of Quantum Field Theory as the Maurer Cartan equation of a classical principal fiber bundle leads to a simple gauge invariant classification of the anomalies in Yang Mills theory and gravity.
Date: May 14, 1985
Creator: Thierry-Mieg, J.
Object Type: Article
System: The UNT Digital Library
Spin-polarization observables in elastic electron scattering from spin-1/2 nuclei (open access)

Spin-polarization observables in elastic electron scattering from spin-1/2 nuclei

Using the formalism of nucleon-nucleon scattering as a starting point, electron scattering from spin-1/2 nuclei is examined. It is seen that high-energy electron-nucleon scattering, for example, exhibits a remarkable simplicity when compared with that of nucleon-nucleon scattering. The 6 amplitudes and 36 nucleon-nucleon observables are reduced to 3 and 9, respectively, by the relativistic nature of the electron. The one-photon exchange mechanism finally reduces the number of amplitudes and independent observables to 2. This treatment serves to extend the spin-polarization ''language'' of hadronic scattering to that of electron scattering also. 6 refs. (LEW)
Date: May 1, 1985
Creator: Conzett, H.E.
Object Type: Article
System: The UNT Digital Library
Biological and Physical Inventory of Clear Creek, Orofino Creek, and the Potlatch River, Tributary Streams of the Clearwater River, Idaho, 1984 Technical Report. (open access)

Biological and Physical Inventory of Clear Creek, Orofino Creek, and the Potlatch River, Tributary Streams of the Clearwater River, Idaho, 1984 Technical Report.

Clear Creek, Orofino Creek, and Potlatch Creek, three of the largest tributaries of the lower Clearwater River Basin, were inventoried during 1984. The purpose of the inventory was to identify where anadromous salmonid production occurs and to recommend enhancement alternatives to increase anadromous salmonid habitat in these streams. Anadromous and fluvial salmonids were found in all three drainages. The lower reach of Clear Creek supported a low population of rainbow-steelhead, while the middle reach supported a much greater population of rainbow-steelhead. Substantial populations of cutthroat trout were also found in the headwaters of Clear Creek. Rainbow-steelhead and brook trout were found throughout Orofino Creek. A predominant population of brook trout was found in the headwaters while a predominant population of rainbow-steelhead was found in the mainstem and lower tributaries of Orofino Creek. Rainbow-steelhead and brook trout were also found in the Potlatch River. Generally, the greatest anadromous salmonid populations in the Potlatch River were found within the middle reach of this system. Several problems were identified which would limit anadromous salmonid production within each drainage. Problems affecting Clear Creek were extreme flows, high summer water temperature, lack of riparian habitat, and high sediment load. Gradient barriers prevented anadromous salmonid passage …
Date: May 1, 1985
Creator: Johnson, David B.
Object Type: Report
System: The UNT Digital Library
Mirror Fusion Test Facility-B (MFTF-B) axicell configuration: NbTi magnet system. Design and analysis summary. Volume 1 (open access)

Mirror Fusion Test Facility-B (MFTF-B) axicell configuration: NbTi magnet system. Design and analysis summary. Volume 1

This report summarizes the designs and analyses produced by General Dynamics Convair for the four Axicell magnets (A1 and A20, east and west), the four Transition magnets (T1 and T2, east and west), and the twelve Solenoid magnets (S1 through S6, east and west). Over four million drawings and specifications, in addition to detailed stress analysis, thermal analysis, electrical, instrumentation, and verification test reports were produced as part of the MFTF-B design effort. Significant aspects of the designs, as well as key analysis results, are summarized in this report. In addition, drawing trees and lists off detailed analysis and test reports included in this report define the locations of the detailed design and analysis data.
Date: May 1, 1985
Creator: Heathman, J.H. & Wohlwend, J.W.
Object Type: Report
System: The UNT Digital Library
Transportable charge in a periodic alternating gradient system (open access)

Transportable charge in a periodic alternating gradient system

A simple set of formulas is derived which relate emittance, line charge density, matched maximum and average envelope radii, occupancy factors, and the (space charge) depressed and vacuum values of tune. This formulation is an improvement on the smooth limit approximation; deviations from exact (numerically determined) relations are on the order of +-2%, while the smooth limit values are in error by up to +-30%. This transport formalism is used to determine the limits of transportable line charge density in an electrostatic quadrupole array, with specific application to the low energy portion of the High Temperature Experiment of Heavy Ion Fusion Accelerator Research. The line charge density limit is found to be essentially proportional to the voltage on the pole faces and the fraction of occupied aperture area. A finite injection energy (greater than or equal to 2 MeV) is required to realize this limit, independent of particle mass.
Date: May 1, 1985
Creator: Lee, E.P.; Fessenden, T.J. & Laslett, L.J.
Object Type: Article
System: The UNT Digital Library
Coherent instability and ion trapping considerations for Aladdin lattices (open access)

Coherent instability and ion trapping considerations for Aladdin lattices

This paper presents the results of an investigation of the effects of ions and coherent collective instabilities on bunched electron beams circulating in the various Aladdin lattices considered in the Aladdin Upgrade Study. It is aimed particularly at identifying those collective and ion phenomena that may be limiting the performance of the present Aladdin with low energy (100 MeV) injection, at ascertaining which of these phenomena would still remain and limit the performance with a full energy (800 MeV) injector for any correction schemes (either active or passive) to alleviate the performance impact of these phenomena; overview of the behavior at low and high energy (and current), the dependence of this behavior on the rf frequency, and the resulting implications for the upgraded Aladdin operations will emerge in the course of this report. 12 refs., 11 figs., 5 tabs.
Date: May 1, 1985
Creator: Chattopadhyay, S.
Object Type: Report
System: The UNT Digital Library