Heavy ion inertial fusion: interface between target gain, accelerator phase space and reactor beam transport revisited (open access)

Heavy ion inertial fusion: interface between target gain, accelerator phase space and reactor beam transport revisited

Recently revised estimates of target gain have added additional optimistic inputs to the interface between targets, accelerators and fusion chamber beam transport. But it remains valid that neutralization of the beams in the fusion chamber is useful if ion charge state Z > 1 or if > 1 kA per beamlet is to be propagated. Some engineering and economic considerations favor higher currents.
Date: February 22, 1984
Creator: Barletta, W. A.; Fawley, W. M.; Judd, D. L.; Mark, J. W. K. & Yu, S. S.
System: The UNT Digital Library
Sequential probability ratio controllers for safeguards radiation monitors (open access)

Sequential probability ratio controllers for safeguards radiation monitors

Sequential hypothesis tests applied to nuclear safeguards accounting methods make the methods more sensitive to detecting diversion. The sequential tests also improve transient signal detection in safeguards radiation monitors. This paper describes three microprocessor control units with sequential probability-ratio tests for detecting transient increases in radiation intensity. The control units are designed for three specific applications: low-intensity monitoring with Poisson probability ratios, higher intensity gamma-ray monitoring where fixed counting intervals are shortened by sequential testing, and monitoring moving traffic where the sequential technique responds to variable-duration signals. The fixed-interval controller shortens a customary 50-s monitoring time to an average of 18 s, making the monitoring delay less bothersome. The controller for monitoring moving vehicles benefits from the sequential technique by maintaining more than half its sensitivity when the normal passage speed doubles.
Date: January 1, 1984
Creator: Fehlau, P. E.; Coop, K. L. & Nixon, K. V.
System: The UNT Digital Library
Hydrodynamics of post CHF region (open access)

Hydrodynamics of post CHF region

Among various two-phase flow regimes, the inverted flow in the post-dryout region is relatively less well understood due to its special heat transfer conditions. The review of existing data indicates further research is needed in the areas of basic hydrodynamics related to liquid core disintegration mechanisms, slug and droplet formations, entrainment, and droplet size distributions. In view of this, the inverted flow is studied in detail both analytically and experimentally. Criteria for initial flow regimes in the post-dryout region are given. Preliminary models for subsequent flow regime transition criteria are derived together with correlations for a mean droplet diameter based on the adiabatic simulation data.
Date: April 1, 1984
Creator: Ishii, M. & De Jarlais, G.
System: The UNT Digital Library
Evaluation of zeolite mixtures for decontaminating high-activity-level water at the Three Mile Island Unit 2 Nuclear Power Station (open access)

Evaluation of zeolite mixtures for decontaminating high-activity-level water at the Three Mile Island Unit 2 Nuclear Power Station

Mixtures of Linde Ionsiv IE-96 and Ionsiv A-51 were evaluated for use in the Submerged Demineralizer System (SDS) that was installed at the Three Mile Island Unit 2 Nuclear Power Station to decontaminate approx. 2780 m/sup 3/ of high-activity-level water. The original SDS flowsheet was conservatively designed for removal of cesium and strontium and would have required the use of approx. 60 SDS columns. Mixed zeolite tests were made on a 10/sup -5/ scale and indicated that the appropriate ratio of IE-96/A-51 was 3/2. A mathematical model was used to predict the performance of the mixed zeolite columns in the SDS configuration and with the intended method of operation. Actual loading results were similar to those predicted for strontium and better than those predicted for cesium. The number of SDS columns needed to process the HALW was reduced to approx. 10. 6 references, 4 figures, 2 tables.
Date: May 1, 1984
Creator: Collins, E. D.; Campbell, D. O.; King, L. J.; Knauer, J. B. & Wallace, R. M.
System: The UNT Digital Library
Rare muon decays and lepton-family number conservation (open access)

Rare muon decays and lepton-family number conservation

A brief historical survey of the discovery of the muon, interest in neutrinoless processes, and lepton-number conservation laws is given. The present view of lepton-number conservation laws and the search for ..mu.. ..-->.. e..gamma.. are described. Other experiments are discussed including ..mu../sup +/ ..-->.. e/sup +/e/sup +/e/sup -/ decay, ..mu../sup -/Z ..-->.. e/sup -/Z reactions, ..mu.. ..-->.. e ..gamma gamma.. decay, other rare muon processes, strangeness-changing muon-number-nonconserving decays, and tau decays. 52 references. (WHK)
Date: April 1, 1984
Creator: Hoffman, C. M.
System: The UNT Digital Library
New particles and interactions (open access)

New particles and interactions

The Working Group on New Particles and Interactions met as a whole at the beginning and at the end of the Workshop. However, much of what was accomplished was done in five subgroups. These were devoted to: (1) new quarks and leptons; (2) technicolor; (3) supersymmetry; (4) rare decays and CP; and (5) substructure of quarks and leptons. Other aspects of new particles, e.g., Higgs, W', Z', fell to the Electroweak Working Group to consider. The central question of this Workshop of comparing anti pp (with L = 10/sup 32//cm/sup 2/-sec) with pp (with L = 10/sup 33//cm/sup 2/-sec) colliders carried through to all these subgroups. In addition there were several other aspects of hadron colliders which were considered: what does an increase in ..sqrt..s gain in cross section and resultant sensitivity to new physics versus an increase in luminosity; will polarized beams or the use of asymmetries be essential in finding new interactions; where and at what level do rate limitations due to triggering or detection systems play a role; and how and where will the detection of particles with short, but detectable, lifetimes be important. 25 references.
Date: April 1, 1984
Creator: Gilman, F. J. & Grannis, P. D.
System: The UNT Digital Library
Tritium Breeding Materials (open access)

Tritium Breeding Materials

Tritium breeding materials are essential to the operation of D-T fusion facilities. Both of the present options - solid ceramic breeding materials and liquid metal materials are reviewed with emphasis not only on their attractive features but also on critical materials issues which must be resolved.
Date: March 1, 1984
Creator: Hollenberg, G. W.; Johnson, C. E. & Abdou, M.
System: The UNT Digital Library
Electron attachment fo halocarbons of interest in gaseous dielectrics (open access)

Electron attachment fo halocarbons of interest in gaseous dielectrics

Total electron attachment rate constants and cross sections for halomethane and haloethane (freon) compounds are summarized and new results are reported for haloethylenes. The relationship between the electron attachment cross section and the breakdown strength of dielectric gases reported earlier is further discussed.
Date: January 1, 1984
Creator: McCorkle, D. L.; Christodoulides, A. A. & Christophorou, L. G.
System: The UNT Digital Library
Hydrogen transport, mixing, and combustion studies (open access)

Hydrogen transport, mixing, and combustion studies

The transport, mixing, and burning of hydrogen inside containments are receiving a great deal of attention. We present detailed models describing this important phenomena and provide several example calculations to show the versatility and accuracy of the methods.
Date: January 1, 1984
Creator: Travis, J. R.
System: The UNT Digital Library
Electro-spark deposition: A technique for producing wear resistant coatings (open access)

Electro-spark deposition: A technique for producing wear resistant coatings

Electro-spark deposition (ESD) is a coating process using short duration, high current electrical pulses to deposit an electrode material on a metallic substrate. A principal attribute of the process is its ability to apply metallurgically bonded coatings with such a low total heat input that the bulk substrate material remains at or near ambient temperatures. A review of the process is briefly given, then current research using WC-TiC and Cr{sub 3}C{sub 2} electrodes to deposit coatings on Type 316 stainless steel and other substrates is presented. The ESD carbide coatings were found to be exceptionally hard, wear-resistant and spalling-resistant in high-stress rubbing tests. Several applications for nuclear reactor components are described. 17 refs., 18 figs., 1 tab.
Date: December 1, 1984
Creator: Sheldon, G. L. & Johnson, R. N.
System: The UNT Digital Library
Resonance ionization spectroscopy of argon, krypton, and xenon using vacuum ultraviolet light (open access)

Resonance ionization spectroscopy of argon, krypton, and xenon using vacuum ultraviolet light

Resonant, single-photon excitation of ground state inert gases requires light in the vacuum ultraviolet spectral region. This paper discusses methods for generating this light. Efficient schemes for ionizing argon, krypton, and xenon using resonant, stepwise single-photon excitation are presented.
Date: April 1, 1984
Creator: Kramer, S. D.
System: The UNT Digital Library
Ceramics for fusion devices (open access)

Ceramics for fusion devices

Ceramics are required for a number of applications in fusion devices, among the most critical of which are magnetic coil insulators, windows for RF heating systems, and structural uses. Radiation effects dominate consideration of candidate materials, although good pre-irradiation properties are a requisite. Materials and components can be optimized by careful control of chemical and microstructural content, and application of brittle material design and testing techniques. Future directions for research and development should include further extension of the data base in the areas of electrical, structural, and thermal properties; establishment of a fission neutron/fusion neutron correlation including transmutation gas effects; and development of new materials tailored to meet the specific needs of fusion reactors.
Date: January 1, 1984
Creator: Clinard, F. W. Jr.
System: The UNT Digital Library
Evaluation of selected approximations used in pressure vessel fluence calculations (open access)

Evaluation of selected approximations used in pressure vessel fluence calculations

In response to concerns over the issue of Pressurized Thermal Shock (PTS), Brookhaven National Laboratory (BNL), under the direction of the USNRC, has developed and benchmarked a methodology for calculating pressure vessel (PV) (>1-MeV) damage fluence. The methodology is based on the DOT-3.5 discrete ordinates transport code and has been shown to yield fluence results in good agreement with measurements and results from other calculations. This paper describes the basic methodology employed in BNL PV fluence calculations, and the results of a number of studies performed to assess the impact of various special effects on the calculated (>1-MeV) PV fluence.
Date: January 1, 1984
Creator: Todosow, M.; Carew, J. F. & Kohut, P.
System: The UNT Digital Library
RFQ radial matching sections and fringe fields (open access)

RFQ radial matching sections and fringe fields

The entrance radial matching section is an extremely important part of any radio-frequency quadrupole (RFQ) linac. It allows a beam having time-independent characteristics to become adapted to the time-dependent focusing in the RFQ. The matching sections proposed in this paper are defined by a four-term potential function and are very effective over lengths of 3 ..beta.. lambda or longer. The fringe field at the RFQ exit is mainly of interest because of the time-varying on-axis potential. The beam can either lose or gain energy, depending on the shape of the fringe field. The same four-term potential function can be used for shaping the vanes at the exit so that the fringe fields can be controlled. This formulation also applies to exit radial matching sections, which would be useful if the beam is to enter another RFQ operated at a higher frequency. 4 references, 4 figures.
Date: April 1, 1984
Creator: Crandall, K. R.
System: The UNT Digital Library
Accelerator-based atomic physics experiments with photon and ion beams (open access)

Accelerator-based atomic physics experiments with photon and ion beams

Accelerator-based atomic physics experiments at Brookhaven presently use heavy-ion beams from the Dual MP Tandem Van de Graaff Accelerator Facility for atomic physics experiments of several types. Work is presently in progress to develop experiments which will use the intense photon beams which will be available in the near future from the ultraviolet (uv) and x-ray rings of the National Synchrotron Light Source (NSLS). Plans are described for experiments at the NSLS and an exciting development in instrumentation for heavy-ion experiments is summarized.
Date: April 26, 1984
Creator: Johnson, B. M.; Jones, K. W. & Meron, M.
System: The UNT Digital Library
Design, fabrication, and testing of the BNL radio frequency quadrupole accelerator (open access)

Design, fabrication, and testing of the BNL radio frequency quadrupole accelerator

The Brookhaven National Laboratory polarized H/sup -/ injection program for the AGS utilizes a Radio Frequency Quadrupole Accelerator for acceleration between the polarized source and the Alvarez Linac. Although operation has commenced with a few ..mu.. amperes of H/sup -/ beam, it is anticipated that future polarized H/sup -/ sources will have a considerably improved output. The RFQ will operate at 201.25 MHz and will be capable of handling a beam current of 0.02 amperes with a duty cycle of 0.25%. The resulting low average power has allowed novel solutions to the problems of vane alignment, rf current contacts, and removal of heat from the vanes. The design philosophy, details of cavity fabrication, and vane machining will be discussed. Results of low and high power rf testing will be presented together with the initial results of operations in the polarized H/sup -/ beam line.
Date: January 1, 1984
Creator: Brown, H.; Clifford, T.; Giordano, S.; Khiari, F.; McKenzie-Wilson, R.; Puglisi, M. et al.
System: The UNT Digital Library
Some uncertainties associated with self-calibration of microPIXE analysis (open access)

Some uncertainties associated with self-calibration of microPIXE analysis

The technique of self-calibration, based on internal labelling of target samples with known amounts of a given element, is often used in conventional PIXE analysis of environmental and biological samples, usually when a large number of samples is to be analyzed. However, extreme care should be exercised when attempting to use self-calibration procedures for microPIXE analysis, because the microdistribution of the labelling element in a drop of solution, for example, is usually nonuniform and particle microbeams with a homogeneous profile are difficult to obtain. This paper presents the results of a series of scanning irradiations by a 20 ..mu..m proton beam across dried solution drops containing known initial concentrations of thorium which had been deposited onto two different backings. Nonuniform distribution of thorium within the dried drops was observed.
Date: January 1, 1984
Creator: Paschoa, A. S.; Wrenn, M. E.; Bruenger, F. W.; Cholewa, M. & Jones, K. W.
System: The UNT Digital Library
Initial conditioning of the TFTR vacuum vessel (open access)

Initial conditioning of the TFTR vacuum vessel

We report on the initial conditioning of the Tokamak Fusion Test Reactor (TFTR) vacuum vessel prior to the initiation of first plasma discharges, and during subsequent operation with high power ohmically-heated plasmas. Following evacuation of the 86 m/sup 3/ vessel with the 10/sup 4/ 1/s high vacuum pumping system, the vessel was conditioned by a 15 A dc glow discharge in H/sub 2/ at a pressure of 5 mTorr. Rapid-pulse discharge cleaning was used subsequently to preferentially condition the graphite plasma limiters. The effectiveness of the discharge cleaning was monitored by measuring the exhaust rates of the primary discharge products (CO/C/sub 2/H/sub 4/, CH/sub 4/, and H/sub 2/O). After 175 hours of glow discharge treatment, the equivalent of 50 monolayers of C and O was removed from the vessel, and the partial pressures of impurity gases were reduced to the range of 10/sup -9/-10/sup -10/ Torr.
Date: January 1, 1984
Creator: Dylla, H. F.; Blanchard, W. R.; Krawchuk, R. B.; Hawryluk, R. J. & Owens, D. K.
System: The UNT Digital Library
5 K neutron irradiation and thermal cycling of NbTi superconductors (open access)

5 K neutron irradiation and thermal cycling of NbTi superconductors

Simulation experiments of magnet operating conditions in a fusion reactor are reported. After approximately half of the lifetime dose the results on a variety of NbTi superconductors show moderate changes of the critical current density j/sub c/ (approx. 10%), the percentage change of j/sub c/ is always larger at high fields (8 T) than at 5 T. After a rapid initial change the resistivity ratios of the Cu-stabilizer are found to decrease only slowly with increasing neutron fluence.
Date: May 1, 1984
Creator: Hahn, P.; Hoch, H.; Weber, H. W.; Birtcher, R. C. & Brown, B. S.
System: The UNT Digital Library
Lumped-circuit model of four-vane RFQ resonator (open access)

Lumped-circuit model of four-vane RFQ resonator

Although the rf cavity code SUPERFISH is a necessary tool for designing rf cavities, it is often useful to have approximate analytic formulas for the electromagnetic properties of a cavity. One approach for the RFQ four-vane cavity is to use the analtytic solutions associated with an inclined plane waveguide. The large capacitive vane loading in the four-vane RFQ resonator allows a convenient representation by a simple lumped-circuit model. Formulas are derived that depend on a single unknown parameter: the vane capacitance per unit length, which can be calculated for different vane geometries using SUPERFISH. The formulas from the model are useful for estimating the RFQ's electromagnetic properties as a function of parameters such as frequency and intervane voltage.
Date: January 1, 1984
Creator: Wangler, T. P.
System: The UNT Digital Library
Weak decays at PEP (open access)

Weak decays at PEP

Results are presented on four aspects of weak decays. The MARK II measurement of the tau lifetime, the MARK II measurement of the D/sup 0/ lifetime, the measurement from several experiments of the semi-leptonic branching fractions of hadrons constraining b and c quarks, and lastly the MAC measurement of the B lifetime. 30 references.
Date: April 1, 1984
Creator: Yelton, J. M.
System: The UNT Digital Library
General-purpose RFQ design program (open access)

General-purpose RFQ design program

We have written a general-purpose, radio-frequency quadrupole (RFQ) design program that allows maximum flexibility in picking design algorithms. This program optimizes the RFQ on any combination of design parameters while simultaneously satisfying mutually compatible, physically required constraint equations. It can be very useful for deriving various scaling laws for RFQs. This program has a friendly user interface in addition to checking the consistency of the user-defined requirements and is written to minimize the effort needed to incorporate additional constraint equations. We describe the program and present some examples.
Date: January 1, 1984
Creator: Wadlinger, E. A.
System: The UNT Digital Library
Developing models for simulation of pinched-beam dynamics in heavy ion fusion. Revision 1 (open access)

Developing models for simulation of pinched-beam dynamics in heavy ion fusion. Revision 1

For heavy-ion fusion energy applications, Mark and Yu have derived hydrodynamic models for numerical simulation of energetic pinched-beams including self-pinches and external-current pinches. These pinched-beams are applicable to beam propagation in fusion chambers and to the US High Temperature Experiment. The closure of the Mark-Yu model is obtained with adiabatic assumptions mathematically analogous to those of Chew, Goldberger, and Low for MHD. Features of this hydrodynamic beam model are compared with a kinetic treatment.
Date: February 22, 1984
Creator: Boyd, J. K.; Mark, J. W. K.; Sharp, W. M. & Yu, S. S.
System: The UNT Digital Library
Photon losses in cosmic ray acceleration in active galactic nuclei (open access)

Photon losses in cosmic ray acceleration in active galactic nuclei

The usual assumption of the acceleration of ultrahigh energy cosmic rays, greater than or equal to 10/sup 18/ eV in quasars, Seyfert galaxies, and other active galactic nuclei is challenged on the basis of the photon interactions with the accelerated nucleons. This is similar to the effect of the black body radiation on particles > 10/sup 20/ eV for times of the age of the universe except that the photon spectrum is harder and the energy density greater by approx. = 10/sup 13/. Hence, a single traversal, radial or circumferential, of radiation whose energy density is no greater than the emitted flux will damp an ultrahigh energy cosmic ray 10/sup 20/ eV by greater than 10/sup 4/ times its energy. Hence, it is unlikely that any reasonable configuration of acceleration can avoid disastrous photon energy loss. A different site for ultrahigh energy cosmic ray acceleration must be found.
Date: January 1, 1984
Creator: Colgate, S. A.
System: The UNT Digital Library