19 Matching Results

Search Results

Advanced search parameters have been applied.

Coherent pion dissociation into three pions on heavy nuclei

Description: A partial wave decomposition was made of the final state 3 pi system produced in the reaction pi /sup -/+ A yields ( pi /sup -/ pi /sup -/ pi /sup + /) + A at 23 GeV/c and for the elements C, Ai, Cu, and Ag. For low 3 pi masses, the 1/sup +/ state is dominant and its t' distribution shows the expected combination of coherent and incoherent components. The t' distribution of the 2/ sup +/ A/sub 2/ state also requires both coherent and incoherent components. (auth)
Date: March 1, 1974
Creator: Kruse, U.E. & Roberts, T.J.
Partner: UNT Libraries Government Documents Department

Calibration of data acquisition system measurement of weld parameters

Description: The purpose of this talk was to outline the calibration and use of the MacSym Data Acquisition System to measure welding parameters in the Tritium Facility`s pinch welders. The point was stressed at the outset of the presentation that these parameters measured are not in any way the final criteria for accepting or rejecting a weld. Rather, the physical dimensions of the weld are the basis for accepting a weld, namely the thickness and closure length. So these welding parameters serve as ranges and boundaries to stay within in order to give the highest level of repeatable success. The seven weld parameters measured are: piston pressure, line pressure, motion, current, energy, line voltage, and force. Each of these measurements are made with installed equipment that is calibrated with standards that are traceable to NBS (National Bureau of Standards). In turn, the DAS is calibrated by adjusting the software to match the installed equipment in its measurements. Also, the DAS provides continual monitoring and display of the weld parameters before and after the weld has been made. A printout is also given of parameters during the weld to give further record of weld data to back up installed measurement instruments not connected to the DAS.
Date: 1988-10~
Creator: Roberts, T.
Partner: UNT Libraries Government Documents Department

Corrosion analysis of decommissioned carbon steel waste water tanks at Brookhaven National Laboratory

Description: A corrosion analysis was carried out on available sections of carbon steels taken from two decommissioned radioactive waste water tanks at Brookhaven National Laboratory. One of the 100,000 gallon tanks suffered from a pinhole failure in the wall which was subsequently patched. From the analysis it was shown that this leak, and two adjacent leaks were initiated by a discarded copper heating coil that had been dropped into the tank during service. The failure mechanism is postulated to have been galvanic attack at points of contact between the tank structure and the coil. Other leaks in the two tanks are also described in this report.
Date: July 1, 1995
Creator: Soo, P. & Roberts, T.C.
Partner: UNT Libraries Government Documents Department

Study of collective effect in ionization cooling

Description: As a charged particle passes through a non-gaseous medium, it polarizes the medium and induces wake fields behind it. Same thing happens in ionization cooling. The interaction with wake fields perturbs the stopping power of beam particles. The perturbation strongly depends on the densities of both the incident beam and the medium. To understand this collective effect, detailed studies have been carried out. Both analytic and simulation results are obtained and compared.
Date: September 1, 2009
Creator: Huang, D.; Ng, K. Y. & Roberts, T. J.
Partner: UNT Libraries Government Documents Department

Studies of a gas-filled helical muon beam cooling channel

Description: A helical cooling channel (HCC) can quickly reduce the six dimensional phase space of muon beams for muon colliders, neutrino factories, and intense muon sources. The HCC is composed of solenoidal, helical dipole, and helical quadrupole magnetic fields to provide the focusing and dispersion needed for emittance exchange as the beam follows an equilibrium helical orbit through a continuous homogeneous absorber. The beam dynamics of a gas-filled helical muon beam cooling channel is studied by using Monte Carlo simulations. The results verify the cooling theory [1] of the helical magnet. The cooling performance has been improved by correcting chromatic aberration and the non-linear effects caused by the ionization energy loss process. With these improvements, a simulated cooling channel of 160 meters length has achieved a reduction of 6-dimensional (6D) phase space by a factor of 50,000.
Date: June 1, 2006
Creator: Yonehara, K.; /Fermilab; Derbenev, Y.; Lab, /Jefferson; Johnson, R.P.; Roberts, T.J. et al.
Partner: UNT Libraries Government Documents Department

Deck model calculation of $pi$$sup -$p $Yields$ $pi$$sup -$$pi$$sup +$$pi$$sup -$p

Description: A Deck-like model for the reaction pi /sup -/p yields pi /sup -/ pi / sup +/ pi /sup -/p is formulated and studied. The model differs from previous Deck calculations in two respects: i) experimental data are used for both pi pi and pi N scattering, and ii) the amplitude has proper Bose symmetry. Feature i) allows one to examine any desired region of 3 pi mass (the A/sub 3/ is treated on the same footing as the A/sub 1/); features i) and ii) allow one to examine all the angular dependence in the final state and to compare with partinl wave analyses of experimental data. The results of a study are presented in which events generated from the model by a Monte Carlo method are plotted and fit in the same way as experimental events. Many of the features of the data are qualitatively reproduced including certain important properties obtained from the partial wave analysis in the A/sub 1/ region. The A/sub 3/ region is not accurately representcd by the model. (auth)
Date: August 1, 1973
Creator: Ascoli, G.; Cutler, R.; Jones, L.M.; Kruse, U.; Roberts, T.; Weinstein, B. et al.
Partner: UNT Libraries Government Documents Department

X-ray reflectivity study of gold films during sputter-deposition

Description: We performed in-situ x-ray reflectivity measurements of gold films during sputter-deposition on polished silicon substrates. The measurements were performed at several substrate temperatures and under two argon pressures. The gold surfaces were also examined by scanning tunneling microscopy after deposition to obtain their real-space topographic images. These images were used to complement the x-ray reflectivity measurements in determining the effect of argon pressure on the gold surface and its height-height difference functions. An approximation for height-height difference functions was employed to analyze the x-ray reflectivity data. The measured interface width during growth follows a simple power-law behavior consistent with recently developed dynamic scaling behavior. The scaling components, however, do not agree well with predictions based on some models in 2 + 1 dimensions.
Date: May 1, 1994
Creator: Chiarello, R.P.; You, H.Y. & Roberts, T.
Partner: UNT Libraries Government Documents Department

Novel Muon Beam Facilities for Project X at Fermilab

Description: Innovative muon beam concepts for intensity-frontier experiments such as muon-to-electron conversion are described. Elaborating upon a previous single-beam idea, we have developed a design concept for a system to generate four high quality, low-energy muon beams (two of each sign) from a single beam of protons. As a first step, the production of pions by 1 and 3 GeV protons from the proposed Project X linac at Fermilab is being simulated and compared with the 8-GeV results from the previous study.
Date: May 1, 2012
Creator: Neuffer, D.V.; /Fermilab; Ankenbrandt, C.M.; Abrams, R.; Roberts, T.J.; Yoshikawa, C.Y. et al.
Partner: UNT Libraries Government Documents Department

Design Concept for nu-STORM: An Initial Very Low-Energy Neutrino Factory

Description: We present a design concept for a {nu} source from a STORage ring for Muons ({nu}STORM). In this initial design a high-intensity proton beam produces {approx}5 GeV pions that provide muons that are captured using 'stochastic injection' within a 3.6 GeV racetrack storage ring. In 'stochastic injection', the {approx}5 GeV pion beam is transported from the target into the storage ring, dispersion-matched into a long straight section. (Circulating and injection orbits are separated by momentum.) Decays within that straight section provide muons that are within the {approx}3.6 GeV/c ring momentum acceptance and are stored for the muon lifetime of {approx}1000 turns. Muon (and pion) decays in the long straight sections provide neutrino beams of precisely known flux and flavor that can be used for precision measurements of electron and muon neutrino interactions, and neutrino oscillations or disappearance at L/E = {approx}1m/MeV. The facility is described, and variations are discussed.
Date: May 1, 2012
Creator: Bross, A.; Geer, S.; Liu, A.; Neuffer, D.; Popovic, M.; /Fermilab et al.
Partner: UNT Libraries Government Documents Department

Integrating the MANX 6-D Muon Cooling Experiment with the MICE Spectrometers

Description: The MANX experiment is to demonstrate the reduction of 6D muon phase space emittance using a continuous liquid absorber to provide ionization cooling in a helical solenoid magnetic channel. The experiment involves the construction of a short two-period long helical cooling channel (HCC) to reduce the muon invariant emittance by a factor of two. The HCC would replace the current cooling section of the MICE experiment now being setup at the Rutherford Appleton Laboratory. The MANX experiment would use the existing MICE spectrometers and muon beam line. This paper shall consider the various approaches to integrate MANX into the RAL hall using the MICE spectrometers. This study shall discuss the matching schemes used to minimize losses and prevent emittance growth between the MICE spectrometers and the MANX HCC. Also the placement of additional detection planes in the matching region and the HCC to improve the resolution will be examined.
Date: May 1, 2009
Creator: Kahn, S.A.; Abrams, R.J.; Ankenbrandt, C.; Cummings, M.A.C.; Johnson, R.P.; Roberts, T. et al.
Partner: UNT Libraries Government Documents Department

Inelastic Neutron Cross Sections on Nuclei at FNAL

Description: Direct experimental measurements of the inelastic cross sections of neutrons on a variety of nuclei have been made at Fermi lab over the energy range from 50 to 350 GeV. These data may be used, together with nucleon-nucleon total cross sections measured through the same energy range, to justify and verify the interpretation of cosmic ray data on interaction mean free paths in air or iron in terms of nucleon-nucleon total cross sections at much higher energies.
Date: May 1, 1977
Creator: Jones, L.W.; /Michigan U. /Queen Mary, U. of London; Gustafson, H.R.; Longo, M.J.; Roberts, T.; Whalley, M. et al.
Partner: UNT Libraries Government Documents Department

In-situ x-ray reflectivity study on growth dynamics of sputter deposited gold on silicon

Description: We performed in-situ x-ray reflectivity measurements to study the growth dynamics of gold sputter deposited onto silicon, using an x- ray scattering chamber equipped with a faced magnetron source where the substrate is held at a right angle relative to the sputtering guns. By operating the guns at low power (1 watt) and under 20 mTorr Ar, we could control the gold deposition rate to less than 1{Angstrom}/sec. The observed x-ray reflectivity for gold deposited onto a silicon substrate held at room temperature may be consistent with nucleated island growth for average gold particle sizes less than 50 {Angstrom}. Above 50 {Angstrom}, the reflectivity data indicates that the gold film uniformly covers the silicon surface, and that as the film thickness is increased the gold-vacuum interface gets progressively rougher. Detailed analysis of room temperature data is in progress, as is the temperature dependence on the roughness of the gold vacuum interface.
Date: November 1, 1991
Creator: Chiarello, R.P.; Kim, H.K.; Roberts, T.; Miller, D.J.; Kampwirth, R.T.; Gray, K.E. et al.
Partner: UNT Libraries Government Documents Department

In-situ x-ray reflectivity study on growth dynamics of sputter deposited gold on silicon

Description: We performed in-situ x-ray reflectivity measurements to study the growth dynamics of gold sputter deposited onto silicon, using an x- ray scattering chamber equipped with a faced magnetron source where the substrate is held at a right angle relative to the sputtering guns. By operating the guns at low power (1 watt) and under 20 mTorr Ar, we could control the gold deposition rate to less than 1{Angstrom}/sec. The observed x-ray reflectivity for gold deposited onto a silicon substrate held at room temperature may be consistent with nucleated island growth for average gold particle sizes less than 50 {Angstrom}. Above 50 {Angstrom}, the reflectivity data indicates that the gold film uniformly covers the silicon surface, and that as the film thickness is increased the gold-vacuum interface gets progressively rougher. Detailed analysis of room temperature data is in progress, as is the temperature dependence on the roughness of the gold vacuum interface.
Date: November 1, 1991
Creator: Chiarello, R. P.; Kim, H. K.; Roberts, T.; Miller, D. J.; Kampwirth, R. T.; Gray, K. E. et al.
Partner: UNT Libraries Government Documents Department

Neutron - Proton Elastic Scattering from 70-GeV/c to 400-GeV/c

Description: The authors have measured neutron-proton elastic scattering cross sections for four-momentum transfers .17 {le} -t {le} 3.5(GeV/c){sup 2}. The logarithmic slope parameter is found to be consistent with existing proton-proton parameterizations. The data also exhibit a dip in the cross section near -t {approx} 1.4(geV/c){sup 2} for incident neutron momenta above 200 GeV/c. Differences between n-p and p-p cross sections are noted in the region .7 {le} -t {le} 1.4(GeV/c){sup 2}.
Date: March 1, 1978
Creator: DeHaven, C.E., Jr.; Ayre, C.A.; Gustafson, H.R.; Jones, L.W.; Longo, M.J.; Ramana Murthy, P.V. et al.
Partner: UNT Libraries Government Documents Department

In situ x-ray diffraction study of CoSi{sub 2} formation during annealing of a Co/Ti bilayer on Si*(100)

Description: X-ray diffraction (XRD) was performed in situ during annealing of a Co/Ti/Si(001) multilayer, which produced an epitaxial CoSi{sub 2} layer. The results indicate that the Ti layer did. not stay intact during the reaction, and thus could not act like a membrane, moderating Co/Si interdiffusion. A strongly textured metastable phase (M) formed prior to CoSi{sub 2} nucleation. This intermediary reaction product was unobservable upon completion of the anneal. We report that nucleation and growth of CoSi{sub 2} on Si(100) took place in the presence of M, a new Co-Ti-Si-(O) phase, located at the metal/Si interface. M might play an important role in the perfection of the silicide. Ti and Co metals intermix already below 300{degrees}C, and there was evidence that metallic Ti precipitated at the surface, commencing at 550{degrees}C.
Date: June 1, 1995
Creator: Selinder, T.I.; Roberts, T.A.; Miller, D.J.; Beno, M.A.; Knapp, G.S.; Gray, K.E. et al.
Partner: UNT Libraries Government Documents Department