A 2-MV multi-beam injector for heavy ion fusion (open access)

A 2-MV multi-beam injector for heavy ion fusion

Construction of a sixteen beam (0.5 A per beam) injector for use in scaled heavy ion fusion experiments is underway at LBL. The machine was designed and partially constructed at LANL. The injector is designed to use carbon arc sources which will provide 25 mA/cm/sup 2/ of extractable current density. The plasma from the arcs is confined electrostatically from drifting into the ion gun before firing the extraction pulse. The acceleration column consists of a set of aperture lenses which both transport the beam and attenuate backstreaming electrons. The acceleration column is mounted inside a 28-inch diameter brazed alumina insulating module. The high voltage for the injector is provided by an inductively loaded and graded Marx generator which resides inside a pressure vessel filled with a 65 psig mixture of 30/percent/ SF/sub 6/ and 70/percent/ N/sub 2/. Data is presented showing the performance of single and multiple carbon arc sources. Measurements show that adequate current density is available. Emittance measurements and efforts to improve emittance and reproducibility are shown. Tests with a 5-tray section of the full 18 tray generator are described showing the evolution of the generator design. 5 refs., 3 figs.
Date: June 1, 1988
Creator: Rutkowski, H. L.; Faltens, A.; Vanecek, D.; Pike, C.; Humphries, S., Jr. & Meyer, E. A.
Object Type: Article
System: The UNT Digital Library
Accelerator research on MBE-4, an experimental multi-beam induction linac (open access)

Accelerator research on MBE-4, an experimental multi-beam induction linac

The multiple beam accelerator MBE-4 is a device for research toward a heavy ion driver for inertial confinement fusion, based on the induction linac concept. Its main goal is proof of the principle of current amplification by acceleration and controlled self-similar beam pulse compression. Into the 16-m long device four beams, each with an initial current of 10 mA are injected from a Marx-driven diode at 200 keV. The current amplification is up to nine-fold, with a final beam energy of about 800 keV in the middle of the bunch. Now that all the apparatus' accelerator sections have been completed, installed and aligned, and its unaccelerated transport properties have been studied, our experimental research has reached the crucial phase of implementing appropriate accelerator schedules that approximate self-similar current-pulse compression. These schedules are established through a close interplay of computations using a one-dimensional simulation code and a manual empirical tuning procedure. In a first approach, with a rather vigorous schedule that uses most of the accelerator modules to their voltage limits, we have determined the limits of our capability for controlled pulse compression, mainly due to waveform shaping of the driving pulse-forming networks. We shall report on these results. In the …
Date: June 1, 1988
Creator: Meuth, H.; Fessenden, T. J.; Keefe, D. & Warwick, A. I.
Object Type: Article
System: The UNT Digital Library
Achromatic beam combiner and bend system for ILSE (Induction Linac System Experiment) (open access)

Achromatic beam combiner and bend system for ILSE (Induction Linac System Experiment)

The lattice configuration of the beam combiner and bend system of the proposed Induction Linac System Experiment (ILSE) is described. These subsystems must transport high current ion beams with large momentum variations within a single pulse (..delta..P/P/sub 0/ less than or equal to +-.1), with minimal beam loss or emittance growth. Configurations which are achromatic through first order, including the effect of image fields have been developed. Calculations of the beam envelope and centroid motion are made with beam dynamics code HICURB, which includes strong space charge effects and chromatic effects through all orders. 5 refs., 5 figs.
Date: June 1, 1988
Creator: Lee, Edward P.
Object Type: Article
System: The UNT Digital Library
Advanced materials for solid oxide fuel cells: Hafnium-Praseodymium-Indium Oxide System (open access)

Advanced materials for solid oxide fuel cells: Hafnium-Praseodymium-Indium Oxide System

The HfO/sub 2/-PrO/sub 1.83/-In/sub 2/O/sub 3/ system has been studied at the Pacific Northwest Laboratory to develop alternative, highly electrically conducting oxides as electrode and interconnection materials for solid oxide fuel cells. A coprecipitation process was developed for synthesizing single-phase, mixed oxide powders necessary to fabricate powders and dense oxides. A ternary phase diagram was developed, and the phases and structures were related to electrical transport properties. Two new phases, an orthorhombic PrInO/sub 3/ and a rhombohedral Hf/sub 2/In/sub 2/O/sub 7/ phase, were identified. The highest electronic conductivity is related to the presence of a bcc, In/sub 2/O/sub 3/ solid solution (ss) containing HfO/sub 2/ and PrO/sub 1.83/. Compositions containing more than 35 mol % of the In/sub 2/O/sub 3/ ss have electrical conductivities greater than 10/sup /minus/1/ (ohm-cm)/sup /minus/1/, and the two or three phase structures that contain this phase appear to exhibit mixed electronic-ionic conduction. The high electrical conductivities and structures similar to the Y/sub 2/O/sub 3/-stabilized ZrO/sub 2/(HfO/sub 2/) electrolyte give these oxides potential for use as cathodes in solid oxide fuel cells. 21 refs.
Date: June 1, 1988
Creator: Bates, J. L.; Griffin, C. W. & Weber, W. J.
Object Type: Report
System: The UNT Digital Library
The all particle method: Coupled neutron, photon, electron, charged particle Monte Carlo calculations (open access)

The all particle method: Coupled neutron, photon, electron, charged particle Monte Carlo calculations

At the present time a Monte Carlo transport computer code is being designed and implemented at Lawrence Livermore National Laboratory to include the transport of: neutrons, photons, electrons and light charged particles as well as the coupling between all species of particles, e.g., photon induced electron emission. Since this code is being designed to handle all particles this approach is called the ''All Particle Method''. The code is designed as a test bed code to include as many different methods as possible (e.g., electron single or multiple scattering) and will be data driven to minimize the number of methods and models ''hard wired'' into the code. This approach will allow changes in the Livermore nuclear and atomic data bases, used to described the interaction and production of particles, to be used to directly control the execution of the program. In addition this approach will allow the code to be used at various levels of complexity to balance computer running time against the accuracy requirements of specific applications. This paper describes the current design philosophy and status of the code. Since the treatment of neutrons and photons used by the All Particle Method code is more or less conventional, emphasis in …
Date: June 1, 1988
Creator: Cullen, D.E.; Perkins, S.T.; Plechaty, E.F. & Rathkopf, J.A.
Object Type: Article
System: The UNT Digital Library
Alpha-particle effects on high-n instabilities in tokamaks (open access)

Alpha-particle effects on high-n instabilities in tokamaks

Hot ..cap alpha..-particles and thermalized helium ash particles in tokamaks can have significant effects on high toroidal mode number instabilities such as the trapped-electron drift mode and the kinetically calculated magnetohydrodynamic ballooning mode. In particular, the effects can be stabilizing, destabilizing, or negligible, depending on the parameters involved. In high-temperature tokamaks capable of producing significant numbers of hot ..cap alpha..-particles, the predominant interaction of the mode with the ..cap alpha..-particles is through resonances of various sorts. In turn, the modes can cause significant anomalous transport of the ..cap alpha..-particles and the helium ash. Here, results of comprehensive linear eigenfrequency-eigenfunction calculations are presented for relevant realistic cases to show these effects. 24 refs., 12 figs., 6 tabs.
Date: June 1, 1988
Creator: Rewoldt, G.
Object Type: Report
System: The UNT Digital Library
Alternate site selection process for UMTRA (Uranium Mill Tailings Remedial Action) project sites (open access)

Alternate site selection process for UMTRA (Uranium Mill Tailings Remedial Action) project sites

The purpose of this document is to describe the guidelines and processes to be used by the Department of Energy (DOE) with input from the affected states and tribes to select alternate disposal sites in compliance with each established cooperative agreement. This document supersedes two previous DOE documents, Criteria for Evaluating Disposal Sites (DOE, 1982) and Alternate Site Selection Process (ASSP) for UMTRA Project Sites (DOE, 1986). This revision of the ASSP was prepared in response to the proposed groundwater protection standards that amend 40 CF 192. The principal modifications are to the ASSP screening criteria for hydrological and geological conditions at candidate disposal sites. The revised screening and selection criteria will assist the project in selecting disposal sites where the probability of compliance with the proposed groundwater standards is high. The ASSP described in Section 2.0 consists of three phases: Phases I -- designation of a search region; Phase II -- preliminary screening of the designated search region; and Phase III -- identification and evaluation of candidate sites. Section 3.0 discusses how the results of the ASSP will be reported. This process provides a technically sound and publicly defensible approach for identifying potentially suitable disposal sites. 4 refs., 1 …
Date: June 1, 1988
Creator: unknown
Object Type: Report
System: The UNT Digital Library
Amplitude and phase acoustic microscopy and its application to QNDE (open access)

Amplitude and phase acoustic microscopy and its application to QNDE

The authors have two amplitude and phase measuring acoustic microscopes, one at low frequency (3--10 MHz) which is used for measurements in metals and composites, and the other operating at frequencies of up to 200 MHz which is used for higher resolution measurements. The added dimension of having phase information allows one to use image processing for a variety of applications. They have demonstrated the following applications with these two microscopes: inversion for reflectance function calculations, depth determination for delaminations in composite materials, slowness curve measurements of depth of trenches in aluminum samples (scaled problem of silicon trenches), and measurement of visco-elastic properties of thin surfactant films on a water surface.
Date: June 1, 1988
Creator: Khuri-Yakub, B. T.; Reinholdtsen, P.; Chou, C. H.; Parent, P. & Cinbis, C.
Object Type: Article
System: The UNT Digital Library
Analysis of beryllium and depleted uranium: An overview of detection methods in aerosols and soils (open access)

Analysis of beryllium and depleted uranium: An overview of detection methods in aerosols and soils

We conducted a survey of commercially available methods for analysis of beryllium and depleted uranium in aerosols and soils to find a reliable, cost-effective, and sufficiently precise method for researchers involved in environmental testing at the Yuma Proving Ground, Yuma, Arizona. Criteria used for evaluation include cost, method of analysis, specificity, sensitivity, reproducibility, applicability, and commercial availability. We found that atomic absorption spectrometry with graphite furnace meets these criteria for testing samples for beryllium. We found that this method can also be used to test samples for depleted uranium. However, atomic absorption with graphite furnace is not as sensitive a measurement method for depleted uranium as it is for beryllium, so we recommend that quality control of depleted uranium analysis be maintained by testing 10 of every 1000 samples by neutron activation analysis. We also evaluated 45 companies and institutions that provide analyses of beryllium and depleted uranium. 5 refs., 1 tab.
Date: June 1, 1988
Creator: Camins, I. & Shinn, J.H.
Object Type: Report
System: The UNT Digital Library
Antiproton production and energy density limitations in targets for the Fermilab pbar source (open access)

Antiproton production and energy density limitations in targets for the Fermilab pbar source

The recent measurements of the antiproton yield as well as the previous ones differ from the predictions which are the basis of the TEVATRON1 Design Report. It was found in reference that at small acceptances, where the data depends essentially only on the forward pbar production cross section, the measured yield data indicates that these cross sections were over estimated by about a factor of 3 in the case of tungsten and about 2.3 in the case of copper. To clear up the situation and to understand what one can do to maximize the luminosity of the TEVATRON Collider this work has been done. Two sides of the antiproton production problem are considered: pbar production cross sections and targeting limitations. Energy deposition density distributions in targets and particle yields are studied via Monte Carlo hadronic and electromagnetic cascade calculations. In the present work we use two independent Monte Carlo programs.
Date: June 1, 1988
Creator: Azhgirey, I. L. & Mokhov, N. V.
Object Type: Report
System: The UNT Digital Library
Assessment of engineered barrier system and design of waste packages (open access)

Assessment of engineered barrier system and design of waste packages

The US Nuclear Regulatory Commission has established two post-closure performance objectives for the Engineered Barrier System (EBS) in a geologic repository. These require containment of the waste followed by controlled release. The EBS for a repository in unsaturated tuff at Yucca Mountain is designed to meet these performance objectives. The major components are the waste form, container, air gap, and borehole liner. Assessment of post-closure performance of the EBS is based on allocating performance for various components toward meeting overall design objectives. Because of the unprecedented time periods considered, 1000 to 10,000 years, computer modeling is essential and will be used in conjunction with testing to assess whether the performance allocations are met. 7 refs., 1 tab.
Date: June 1, 1988
Creator: Ramspott, L.D.
Object Type: Article
System: The UNT Digital Library
Be in the Salton Sea Geothermal System, California (USA): Salton Sea Scientific Drilling Project, California State 2-14 well: Final report (open access)

Be in the Salton Sea Geothermal System, California (USA): Salton Sea Scientific Drilling Project, California State 2-14 well: Final report

The Salton Sea Geothermal System lies in the old Colorado River Delta, where sediments have been metamorphosed by hydrothermal processes. Fluids, from well Fee No. 5 and deep hole SSSDP California State 2-14, as well as rocks from the deep hole were studied for /sup 10/Be and /sup 9/Be. In the solid samples /sup 10/Be concentration ranges from 29 to 259 /times/ 10/sup 6/ atom/g and /sup 9/Be from 0.49 to 2.52 ppM. The /sup 10/Be concentration in the geothermal waters ranges from 2 /times/ 10/sup 3/ to 2.9 /times/ 10/sup 6/ atom/g and /sup 9/Be from 0.7 to 16.6 ppB. Compared to the steady-state inventory which represents the quantity of /sup 10/Be expected from rain deposition alone (/approximately/1 /times/ 10/sup 12/ atom/cm/sup 2/), the /sup 10/Be inventory in the deep core is 3 orders of magnitude higher (>1 /times/ 10/sup 15/ atom/cm/sup 2/). This indicates that most /sup 10/Be is inherited and that the sediments hosting the geothermal field down to 3250m are young, less than few million year old. /sup 10/Be and /sup 9/Be Kds decrease from surface to bottom (3333 to 48 and 727 to 393, respectively) expressing the strong leaching effect of the solid material by …
Date: June 1, 1988
Creator: Valette-Silver, N.J.
Object Type: Report
System: The UNT Digital Library
Black liquor gasification phase 2D final report (open access)

Black liquor gasification phase 2D final report

This report covers work conducted by Rockwell International under Amendment 5 to Subcontract STR/DOE-12 of Cooperative Agreement DE-AC-05-80CS40341 between St. Regis Corporation (now Champion International) and the Department of Energy (DOE). The work has been designated Phase 2D of the overall program to differentiate it from prior work under the same subcontract. The overall program is aimed at demonstrating the feasibility of and providing design data for the Rockwell process for gasifying Kraft black liquor. In this process, concentrated black liquor is converted into low-Btu fuel gas and reduced melt by reaction with air in a specially designed gasification reactor.
Date: June 1, 1988
Creator: Kohl, A.L. & Stewart, A.E.
Object Type: Report
System: The UNT Digital Library
Bootstrap Confidence Intervals in a Complex Situation: A Sequential Paired Clinical Trial (open access)

Bootstrap Confidence Intervals in a Complex Situation: A Sequential Paired Clinical Trial

This paper considers the problem of determining a confidence interval for the difference between two treatments in a simplified sequential paired clinical trial, which is analogous to setting an interval for the drift of a random walk subject to a parabolic stopping boundary. Three bootstrap methods of construction are applied: Efron's accelerated bias-covered, the DiCiccio-Romano, and the bootstrap-t. The results are compared with a theoretical approximate interval due to Siegmund. Difficulties inherent in the use of these bootstrap methods in a complex situations are illustrated. The DiCiccio-Romano method is shown to be the easiest to apply and to work well. 13 refs.
Date: June 1, 1988
Creator: Morton, Sally C.
Object Type: Article
System: The UNT Digital Library
Boundary conditions for OH, L, and H-mode simulations (open access)

Boundary conditions for OH, L, and H-mode simulations

A method for prescribing appropriate boundary conditions for predictive simulations using flux-surface-averaged plasma transport codes is described. The model makes use of the present theoretical understanding of L and H-mode transport mechanisms and is consistent with trends in existing data. It is calibrated against an ASDEX experiment and used to predict the edge behavior in CIT. 14 refs., 7 figs.
Date: June 1, 1988
Creator: Singer, C. E.; Bateman, G. & Stotler, D. P.
Object Type: Report
System: The UNT Digital Library
Canonical integration and analysis of periodic maps using non-standard analysis and life methods (open access)

Canonical integration and analysis of periodic maps using non-standard analysis and life methods

We describe a method and a way of thinking which is ideally suited for the study of systems represented by canonical integrators. Starting with the continuous description provided by the Hamiltonians, we replace it by a succession of preferably canonical maps. The power series representation of these maps can be extracted with a computer implementation of the tools of Non-Standard Analysis and analyzed by the same tools. For a nearly integrable system, we can define a Floquet ring in a way consistent with our needs. Using the finite time maps, the Floquet ring is defined only at the locations s/sub i/ where one perturbs or observes the phase space. At most the total number of locations is equal to the total number of steps of our integrator. We can also produce pseudo-Hamiltonians which describe the motion induced by these maps. 15 refs., 1 fig.
Date: June 1, 1988
Creator: Forest, E. & Berz, M.
Object Type: Article
System: The UNT Digital Library
Characteristics of low-q disruptions in PBX (open access)

Characteristics of low-q disruptions in PBX

The results of this study indicate that even within the relatively narrow low-q/sub /psi// operating space, there is a continuum in the characteristics of the low-q/sub /psi// disruptions with a primary dependence on the value of <..beta../sub t/>. While the ideal external kink instability may give rise to the growing oscillations that lead up to the ultimate disruption, the instabilities are weighted towards the edge only at the lowest-q/sub /psi// (less than or equal to 3) and highest <..beta../sub t/>. At even slightly higher q/sub /psi//, the oscillations are also seen, at the same frequency, in the interior of the plasma. The results further indicate that effects outside the scope of ideal MHD theory may play a significant role in low-q/sub /psi// disruptions. 34 refs., 19 figs.
Date: June 1, 1988
Creator: Kaye, S.M.; Jahns, G.L.; Morris, A.W.; Sesnic, S.; Bol, K.; Chance, M. et al.
Object Type: Report
System: The UNT Digital Library
Charmed and strange baryon production in 29 GeV electron positron annihilation (open access)

Charmed and strange baryon production in 29 GeV electron positron annihilation

This dissertation presents measurements of the production rates of baryons with different strangeness and spin. The analyses presented here use data taken with the Mark III detector at the PEP storage ring, operating at a center of mass energy of 29 GeV. The ..xi../sup /minus// production rate is measured to be 0.017 +- 0.004 +- 0.004 per hadronic event, ..cap omega../sup /minus// production is measured to be 0.014 +- 0.006 +- 0.004 per hadronic event, and ..xi..*/sup 0/ production is less than 0.006 per hadronic event at a 90% confidence level. These measurements place strong constraints on models of baryon production. In particular, the unexpectedly high rate of ..cap omega../sup /minus// production is difficult to explain in any diquark based model. Semileptonic ..lambda../sub c//sup +/ decays have also been observed. Because neither the branching ratios nor the production rate are well known, it is difficult to interpret these results. However, they do indicate that the branching ratio for ..lambda../sub c//sup +/ ..-->.. ..lambda..l..nu.. may be higher than previous experimental measurements. 85 refs., 45 figs., 12 tabs.
Date: June 1, 1988
Creator: Klein, S.R.
Object Type: Report
System: The UNT Digital Library
Chiral gauge theory on a lattice: Are anomalous gauge theories renormalizable (open access)

Chiral gauge theory on a lattice: Are anomalous gauge theories renormalizable

We discuss the quantization of chiral gauge theories by lattice regularization, carefully treating the effects of the chiral anomaly. We derive a chiral gauge invariant lattice fermion action from a chiral gauge variant Wilson fermion action without changing its partition function. By lattice power counting for this formula we show that anomalous gauge theories as well as anomaly-free gauge theories are renormalizable even in 4-dimensions. Some applications and implications of this result and problems therein are discussed. 16 refs.
Date: June 1, 1988
Creator: Aoki, S.
Object Type: Article
System: The UNT Digital Library
Columbia River White Sturgeon Genetics and Early Life History: Population Segregation and Juvenile Feeding Behavior, 1987 Final Report. (open access)

Columbia River White Sturgeon Genetics and Early Life History: Population Segregation and Juvenile Feeding Behavior, 1987 Final Report.

The geographic area of the genetics study broadly covered the distribution range of sturgeon in the Columbia from below Bonneville Dam at Ilwaco at Lake Roosevelt, the Upper Snake River, and the Kootenai River. The two remote river sections provided data important for enhancement considerations. There was little electrophoretic variation seen among individuals from the Kootenai River. Upper Snake river sturgeon showed a higher percentage of polymorphic loci than the Kootenai fish, but lower than the other areas in the Columbia River we sampled. Sample size was increased in both Lake Roosevelt and at Electrophoretic variation was specific to an individual sampling area in several cases and this shaped our conclusions. The 1987 early life history studies concentrated on the feeding behavior of juvenile sturgeon. The chemostimulant components in prey attractive to sturgeon were examined, and the sensory systems utilized by foraging sturgeon were determined under different environmental conditions. These results were discussed with regard to the environmental changes that have occurred in the Columbia River. Under present river conditions, the feeding mechanism of sturgeon is more restricted to certain prey types, and their feeding range may be limited. In these situations, enhancement measures cannot be undertaken without consideration given …
Date: June 1, 1988
Creator: Brannon, Ernest L.
Object Type: Report
System: The UNT Digital Library
A comparison of uncertainty analysis methods using a groundwater flow model (open access)

A comparison of uncertainty analysis methods using a groundwater flow model

This report evaluates three uncertainty analysis methods that are proposed for use in performances assessment activities within the OCRWM and Nuclear Regulatory Commission (NRC) communities. The three methods are Monte Carlo simulation with unconstrained sampling, Monte Carlo simulation with Latin Hypercube sampling, and first-order analysis. Monte Carlo simulation with unconstrained sampling is a generally accepted uncertainty analysis method, but it has the disadvantage of being costly and time consuming. Latin Hypercube sampling was proposed to make Monte Carlo simulation more efficient. However, although it was originally formulated for independent variables, which is a major drawback in performance assessment modeling, Latin Hypercube can be used to generate correlated samples. The first-order method is efficient to implement because it is based on the first-order Taylor series expansion; however, there is concern that it does not adequately describe the variability for complex models. These three uncertainty analysis methods were evaluated using a calibrated groundwater flow model of a unconfined aquifer in southern Arizona. The two simulation methods produced similar results, although the Latin Hypercube method tends to produce samples whose estimates of statistical parameters are closer to the desired parameters. The mean travel times for the first-order method does not agree with those …
Date: June 1, 1988
Creator: Doctor, P. G.; Jacobson, E. A. & Buchanan, J. A.
Object Type: Report
System: The UNT Digital Library
A computer model of gas generation and transport within TRU waste drums (open access)

A computer model of gas generation and transport within TRU waste drums

A computer model has been developed to predict radiolytic gas generation and transport within Transuranic (TRU) waste drums and surrounding enclosures. Gas generation from the radiolytic decomposition of organic material contaminated with plutonium is modeled and the concentrations of gas throughout the waste drum and enclosures are determined using a diffusional transport model. The model accurately reproduces experimentally measured gas concentrations. With polyethylene waste in unvented drums, the model predicts that the concentration of hydrogen gas can exceed 4 mole percent (lower flammable limit) with only about 5 curies of plutonium. If the drum liner is punctured and an unrestricted 0.75-in. carbon composite filter vent is installed in the drum lid, the plutonium loading can be increased to 240 Ci without generating flammable gas mixtures. Larger diameter filters can be used to increase the curie loading. The model has been used to show that shipments of 1000 Ci of plutonium-238 contaminated waste from Savannah River to the WIPP site are feasible using the TRUPACT shipping container. 10 refs., 17 figs., 6 tabs.
Date: June 1, 1988
Creator: Smith, F. G., III
Object Type: Report
System: The UNT Digital Library
Contribution to the United States position paper on sodium fires: Design basis and testing (open access)

Contribution to the United States position paper on sodium fires: Design basis and testing

There were four large-scale sodium fire tests completed to provide a data base for computer code validation; three for the ABCOVE program and one for the SOFICOV program. The purpose of the ABCOVE program is to provide a basis for judging the adequacy of existing aerosol behavior computer codes to describe inherent aerosol attenuation in containment buildings during postulated accidents. The program involves both analytical calculations by code developers and users, and large-scale confirmatory tests in the 850-m/sup 3/ containment vessel of the Containment Systems Test Facility (CSTF) operated by the Westinghouse Hanford Company. A key element of both programs is that all code calculations are made without knowledge of the experimental results, and thus, provide a true measure of the code capabilities without benefit of post-test fitting.
Date: June 1, 1988
Creator: McCormack, J.D.
Object Type: Article
System: The UNT Digital Library
A controlled source audiomagnetotelluric investigation of the Ennis Hot Springs Geothermal Area, Ennis, Montana: Final report: Part 2 (open access)

A controlled source audiomagnetotelluric investigation of the Ennis Hot Springs Geothermal Area, Ennis, Montana: Final report: Part 2

A controlled-source audiomagnetotelluric survey (CSAMT) at the Ennis Hot Springs geothermal area revealed a low resistivity anomaly (3 ohm-m to 10 ohm-m) in the vicinity of the hot springs. The hot springs issue from the base of a gravel terrace on the west side of the Madison Valley. Low apparent resistivities extend to the west under the gravel terrace as well as to the north in an elongated ''plume''. To the southwest the apparent resistivity increases rapidly due to an uplift in the valley basement. One-dimensional inverse modeling in the center of the valley indicates a buried conductive layer probably due to a thick layer of clay-bearing sediments since a nearby test well does not show elevated temperatures. Near the hot springs, one-dimensional inverse modeling did not prove useful, partly because of the two and three-dimensional nature of the structure. Two-dimensional forward modeling near the hot springs provides a more quantitative delineation of the low resistivity zone and of the faulted basement uplifts to the west and south. Details of the structure beneath the conductive zone near the hot springs are difficult to resolve and most of the model control in this region is provided by well logs and seismic …
Date: June 1, 1988
Creator: Emilsson, Gunnar Robert
Object Type: Report
System: The UNT Digital Library