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The Russian-American gallium solar neutrino experiment

Description: The Russian-American Gallium solar neutrino Experiment (SAGE) is described. The solar neutrino flux measured by 31 extractions through October, 1993 is presented. The result of 69 {+-} 10{sub {minus}7}{sup +5} SNU is to be compared with a standard solar model prediction of 132 SNU. The status of a {sup 51}Cr neutrino source irradiation to test the overall operation of the experiment is also presented.
Date: August 1, 1995
Creator: Elliott, S.R.; Wilkerson, J.F. & Abdurashitov, J.N.
Partner: UNT Libraries Government Documents Department

Best Estimate Radiation Flux Value-Added Procedure: Algorithm Operational Details and Explanations

Description: This document describes some specifics of the algorithm for best estimate evaluation of radiation fluxes at Southern Great Plains (SGP) Central Facility (CF). It uses the data available from the three co-located surface radiometer platforms at the SGP CF to automatically determine the best estimate of the irradiance measurements available. The Best Estimate Flux (BEFlux) value-added procedure (VAP) was previously named Best Estimate ShortWave (BESW) VAP, which included all of the broadband and spectral shortwave (SW) measurements for the SGP CF. In BESW, multiple measurements of the same quantities were handled simply by designating one as the primary measurement and using all others to merely fill in any gaps. Thus, this “BESW” is better termed “most continuous,” since no additional quality assessment was applied. We modified the algorithm in BESW to use the average of the closest two measurements as the best estimate when possible, if these measurements pass all quality assessment criteria. Furthermore, we included longwave (LW) fields in the best estimate evaluation to include all major components of the surface radiative energy budget, and renamed the VAP to Best Estimate Flux (BEFLUX1LONG).
Date: October 1, 2002
Creator: Shi, Y. & Long, C. N.
Partner: UNT Libraries Government Documents Department

Uncertainty Analysis Technique for OMEGA Dante Measurements

Description: The Dante is an 18 channel X-ray filtered diode array which records the spectrally and temporally resolved radiation flux from various targets (e.g. hohlraums, etc.) at X-ray energies between 50 eV to 10 keV. It is a main diagnostics installed on the OMEGA laser facility at the Laboratory for Laser Energetics, University of Rochester. The absolute flux is determined from the photometric calibration of the X-ray diodes, filters and mirrors and an unfold algorithm. Understanding the errors on this absolute measurement is critical for understanding hohlraum energetic physics. We present a new method for quantifying the uncertainties on the determined flux using a Monte-Carlo parameter variation technique. This technique combines the uncertainties in both the unfold algorithm and the error from the absolute calibration of each channel into a one sigma Gaussian error function. One thousand test voltage sets are created using these error functions and processed by the unfold algorithm to produce individual spectra and fluxes. Statistical methods are applied to the resultant set of fluxes to estimate error bars on the measurements.
Date: May 7, 2010
Creator: May, M J; Widmann, K; Sorce, C; Park, H & Schneider, M
Partner: UNT Libraries Government Documents Department

Distributions of Alpha Particles Escaping to the Wall because of Sawtooth Oscillations in TFTR

Description: It has been observed experimentally in deuterium-tritium shots of the Tokamak Fusion Test Reactor (TFTR) that crashes of sawtooth oscillations may result in very inhomogeneous flux of alpha particles to the wall. Namely, measurements with four detectors installed at the wall at 20°, 45°, 60°, and 90° below the midplane of the torus have shown that the alpha flux to the wall is strongly peaked at the 20° and 90° detectors and on the noise level at the 45° detector. To explain this phenomenon, both theoretical analysis and numerical simulation have been carried out. It is concluded that the "crash-induced prompt loss," i.e., the orbital loss of marginally trapped particles arising because of the crash-induced orbit transformation of circulating particles, is responsible for the flux to the 90° and 60° detectors, whereas the crash-induced stochastic diffusion of moderately trapped particles explains the large signal at the 20° detector. The calculated poloidal distributions of the integral alpha flux are in reasonable agreement with experimental data. In addition to the integral flux, the flux of particles with given energy was calculated. The energy spectrum of the escaping particles has also been calculated, which can be used for diagnostics of the crash type.
Date: November 1, 1998
Creator: Kolesnichenko, Ya.I.; Lutsenko, V.V.; White, R.B. & Yakovenko, Yu.V., Zweben, S.J.
Partner: UNT Libraries Government Documents Department

Studies of modern and ancient solar energetic particles

Description: Modern solar energetic particles (SEPs) have been studied for about 50 years by satellites and ground-based observations. These measurements indicate much about the nature of SEPs but cover too short a period to quantify the probabilities of very large solar particle events. Many SEPs have high enough energies to make nuclides in material in which they interact. Some nuclides measured in lunar samples have been used to extend the record about SEPs back several million years. Some new measurements of modern SEPs during the last solar cycle and new results for nuclides made by SEPs in lunar samples are presented and their implications discussed. Both the modern and ancient records need to be improved, and methods to get a better understanding of solar energetic particles are discussed. The SEP average fluxes from both sets of records are similar, and both sets can be used to show that huge fluxes of SEPs are very rare.
Date: October 1, 1998
Creator: Reedy, R.C.
Partner: UNT Libraries Government Documents Department

A Simple X-Ray Focusing Mirror Using Float Glass

Description: In our recent x-ray photon correlation spectroscopy (speckle) experiments at NSLS, one of the challenges is to increase the coherent photon flux through a pinhole, whose size is chosen to match the beam`s horizontal transverse coherence length {ital l{sub h}}. We adopted an approach to vertically focus the x-ray beam so as to match its vertical transverse coherence length {ital l{sub v}}, (at NSLS X13, {ital l{sub v}}{approximately} 50{ital l{sub h}}, {ital l{sub h}}{approximately} 12 {mu}m at 3 KeV) with {ital l{sub h}}. By demagnifying the vertical size by a factor of {ital l{sub v}/l{sub h}}, we expect to increase the intensity of the x-rays through the pin hole by the same factor while keeping the beam coherent. A piece of commercial 3/8 inch thick float glass, by virtue of its low surface roughness ({approximately}3{Angstrom} rms), good reflectivity in the low photon energy range of interest and low cost, was chosen as the mirror material. A computer controlled motorized bender with a four point bending mechanism was designed and built to bend the float glass to a continuously variable radius of curvature from {approximately}700 m (intrinsic curvature of the glass surface) to < 300 m, measured with the Long Trace Profiler at the BNL Metrology Lab. This mirror bender assembly allows us to continuously change the focal length of the x-ray mirror down to 0.5 m under our experimental conditions. At the NSLS X13 Prototype Small Gap Undulator (PSGU) beamline, we were able to focus the x-ray beam from a vertical size of 0.5 mm to {approximately} 25{mu}m at the focal point 54 cm from the mirror center, thus increasing the photon flux density by a factor of 20. Results also show that, as expected, at an incident angle of 9 mrad, the mirror cuts off the harmonics of the ...
Date: October 1, 1996
Creator: Yin, Z; Berman, L.; Siddons, D.P.; Dierker, S & Dufresne, E.
Partner: UNT Libraries Government Documents Department

Solar particle events and their radiation threats

Description: Energetic particles from the Sun have only been studied in detail during the last three decades. The modern record is good, although the number of the largest solar particle events are very few. The nuclides made by solar energetic particles in lunar rocks have been used to extend the record of these particles {approximately} 10{sup 7} years. The modern and ancient records are similar. By combining both sets of data, it has been inferred that solar particle events much larger than the largest events observed during the last four solar cycles are very rare.
Date: March 1998
Creator: Reedy, R. C.
Partner: UNT Libraries Government Documents Department

How well do we need to know the beam properties at a neutrino factory?

Description: In principle, a neutrino factory can produce a beam with a well known {nu}{sub e} and {nu}{sub {mu}} flux. In practice, the uncertainties on the muon beam properties will introduce uncertainties into the calculated neutrino fluxes. The authors explore the relationship between the beam systematics and the systematic uncertainties on predicted event rates at a far site. The desired precision with which they must know the beam momentum, direction, divergence, momentum spread, and polarization are discussed.
Date: February 29, 2000
Creator: Geer, S. & Crisan, C.
Partner: UNT Libraries Government Documents Department

Undulator A diagnostics at the Advanced Photon Source

Description: Diagnostics of Undulator A{number_sign}2 (UA2) radiation was performed during the October 1997 mn at the Advanced Photon Source (APS). The UA2 undulator is a standard 3.3-cm-period APS Undulator A, which was positioned downstream from the center of the straight section at Sector 8. The diagnostics included the angular-spectral measurements of the undulator radiation to determine the undulator radiation absolute spectral flux and the particle beam divergence. The results of the absolute spectral flux measurements are compared to the undulator spectrum calculated from measured undulator magnetic field. The particle`s energy spread was determined from spectra comparison. Previously, the authors reported the first measurements made on Undulator A at the APS. The purpose of the present report is to summarize the results of the diagnostics performed on the Sector 8 undulator at the request of the IMM-CAT staff, and to present a more general discussion of undulator radiation sources at the APS and details of their diagnostics.
Date: January 1, 1998
Creator: Ilinski, P.
Partner: UNT Libraries Government Documents Department

Fast resistive bolometry

Description: Resistive bolometry is an accurate, robust, spectrally broadband technique for measuring absolute x-ray fluence and flux. Bolometry is an independent technique for x-ray measurements that is based on a different set of physical properties than other diagnostics such as x-ray diodes, photoconducting detectors, and P-I-N diodes. Bolometers use the temperature-driven change in element resistivity to determine the total deposited energy. The calibration of such a device is based on fundamental material properties and its physical dimensions. The authors describe the use of nickel and gold bolometers to measure x rays generated by high power Z pinches on Sandia`s Saturn and Z accelerators. The Sandia bolometer design described herein has a pulse response of {approximately}1 ns. They describe in detail the fabrication, fielding, and data analysis issues leading to highly accurate x-ray measurements. The fundamental accuracy of resistive bolometry will be discussed.
Date: June 1, 1998
Creator: Spielman, R.B.; Deeney, C.; Fehl, D.L.; Hanson, D.L.; Keltner, N.R.; McGurn, J.S. et al.
Partner: UNT Libraries Government Documents Department

Site scientific mission plan for the Southern Great Plains CART site: July--December 1998

Description: The Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) site was designed to help satisfy the data needs of the Atmospheric Radiation Measurement (ARM) Program Science Team. This Site Scientific Mission Plan defines the scientific priorities for site activities during the six months beginning on July 1, 1998, and looks forward in lesser detail to subsequent six-month periods. The primary purpose of this document is to provide scientific guidance for the development of plans for site operations. It also provides information on current plans to the ARM functional teams (Management Team, Data and Science Integration Team [DSIT], Operations Team, and Instrument Team [IT]) and serves to disseminate the plans more generally within the ARM Program and among the members of the Science Team. This document includes a description of the operational status of the site and the primary site activities envisioned, together with information concerning approved and proposed intensive observation periods (IOPs). The primary users of this document are the site operator, the site program manager, the Site Scientist Team (SST), the Science Team through the ARM Program science director, the ARM program Experiment Center, and the aforementioned ARM Program functional teams. This plan is a living document that is updated and reissued every six months as the observational facilities are developed, tested, and augmented and as priorities are adjusted in response to developments in scientific planning and understanding.
Date: July 1, 1998
Creator: Peppler, R.A.; Lamb, P. & Sisterson, D.L.
Partner: UNT Libraries Government Documents Department

Observation of the moon shadow in deep underground muon flux.

Description: A shadow of the moon, with a statistical significance of 5{sigma}, has been observed in the underground muon flux at a depth of 2090 mwe using the Soudan 2 detector. The angular resolution of the detector is well described by a Gaussian with {sigma} {le}0.3{degree}. The position of the shadow confirms the alignment of the detector to better than 0.15{degree}. This alignment has remained stable during 10 years of data taking from 1989 through 1998.
Date: June 22, 1999
Creator: Allison, W. W. M.; Alner, G. J.; Ayres, D. S.; Cobb, J. H.; Fields, T. H.; Goodman, M. C. et al.
Partner: UNT Libraries Government Documents Department

Detailed flux calculations for the conceptual design of the Advanced Neutron Source Reactor

Description: A detailed MCNP model of the Advanced Neutron Source Reactor has been developed. All reactor components inside the reflector tank were included, and all components were highly segmented. Neutron and photon multigroup flux spectra have been calculated for each segment in the model, and thermal-to-fast neutron flux ratios were determined for each component segment. Axial profiles of the spectra are provided for all components of the reactor. Individual segment statistical uncertainties were limited wherever possible, and the group fluxes for all important reflector components have a standard deviation below 10%.
Date: May 1, 1995
Creator: Wemple, C.A.
Partner: UNT Libraries Government Documents Department

Preliminary Report on Supersonic Jet Modeling

Description: The report figures show the problem setup and radiation temperature (Tr) results for a simulation of a solid gold half-hohlraum irradiated with the 12 specified Omega laser beams using the incident pulse shape for shot 18080. The experimental package is not included in this modeling; the hohlraum has a solid gold wall at the experimental package position. Figure-1 shows the initial zoning and focusing of the two sets of laser beams. Figure 2 identifies the 4 regions over which we track the Tr as the simulation proceeds. Figures 3a-3d are plots of Tr in keV versus time in ns for the regions specified in Figure 2. Figure 4 is a plot of Tr in keV versus time in ns. This Tr is computed from the emitted radiation flux using the original size of the laser entrance hole.
Date: June 6, 2000
Creator: Lasinski, B.F.
Partner: UNT Libraries Government Documents Department

National Ignition Campaign Hohlraum Energetics

Description: The first series of experiments on the National Ignition Facility (NIF) [E. I. Moses, R. N. Boyd, B. A. Remington, C. J. Keane, and R. Al-Ayat, 'The National Ignition Facility: ushering in a new age for high energy density science,' Phys. Plasmas 16, 041006 (2009)] tested ignition hohlraum 'energetics,' a term described by four broad goals: (1) Measurement of laser absorption by the hohlraum; (2) Measurement of the x-ray radiation flux (T{sub RAD}{sup 4}) on the surrogate ignition capsule; (3) Quantitative understanding of the laser absorption and resultant x-ray flux; and (4) Determining whether initial hohlraum performance is consistent with requirements for ignition. This paper summarizes the status of NIF hohlraum energetics experiments. The hohlraum targets and experimental design are described, as well as the results of the initial experiments. The data demonstrate low backscattered energy (&lt; 10%) for hohlraums filled with helium gas. A discussion of our current understanding of NIF hohlraum x-ray drive follows, including an overview of the computational tools, i.e., radiation-hydrodynamics codes, that have been used to design the hohlraums. The performance of the codes is compared to x-ray drive and capsule implosion data from the first NIF experiments. These results bode well for future NIF ignition hohlraum experiments.
Date: November 16, 2009
Creator: Meezan, N B; Atherton, L J; Callahan, D A; Dewald, E L; Dixit, S N; Dzenitis, E G et al.
Partner: UNT Libraries Government Documents Department

Physics of String Flux Compactifications

Description: We provide a qualitative review of flux compactifications of string theory, focusing on broad physical implications and statistical methods of analysis.
Date: February 20, 2007
Creator: Denef, Frederik; U., /Leuven; Douglas, Michael R.; /Rutgers U., Piscataway /IHES, Bures-sur-Yvette; Kachru, Shamit & /Stanford U., Phys. Dept. /SLAC
Partner: UNT Libraries Government Documents Department

X-ray Conversion Efficiency of high-Z hohlraum wall materials for indirect drive ignition

Description: We measure the conversion efficiency of 351 nm laser light to soft x-rays (0.1-5 keV) for Au, U and high Z mixtures 'cocktails' used for hohlraum wall materials in indirect drive ICF. We use spherical targets in a direct drive geometry, flattop laser pulses and laser smoothing with phase plates to achieve constant and uniform laser intensities of 10{sup 14} and 10{sup 15} W/cm{sup 2} over the target surface that are relevant for the future ignition experiments on NIF. The absolute time and spectrally-resolved radiation flux is measured with a multichannel soft x-ray power diagnostic. The conversion efficiency is then calculated by dividing the measured x-ray power by the incident laser power from which the measured laser backscattering losses is subtracted. After {approx}0.5 ns, the time resolved x-ray conversion efficiency reaches a slowly increasing plateau of 95% at 10{sup 14} W/cm{sup 2} laser intensity and of 80% at 10{sup 15} W/cm{sup 2}. The M-band flux (2-5 keV) is negligible at 10{sup 14} W/cm{sup 2} reaching {approx}1% of the total x-ray flux for all target materials. In contrast, the M-band flux is significant and depends on the target material at 10{sup 15} W/cm{sup 2} laser intensity, reaching values between 10% of the total flux for U and 27% for Au. Our LASNEX simulations show good agreement in conversion efficiency and radiated spectra with data when using XSN atomic physics model and a flux limiter of 0.15, but they underestimate the generated M-band flux.
Date: February 22, 2008
Creator: Dewald, E; Rosen, M; Glenzer, S H; Suter, L J; Girard, F; Jadaud, J P et al.
Partner: UNT Libraries Government Documents Department

A HIGH REPETITION RATE VUV-SOFT X-RAY FEL CONCEPT

Description: We report on design studies for a seeded FEL light source that is responsive to the scientific needs of the future. The FEL process increases radiation flux by several orders of magnitude above existing incoherent sources, and offers the additional enhancements attainable by optical manipulations of the electron beam: control of the temporal duration and bandwidth of the coherent output, reduced gain length in the FEL, utilization of harmonics to attain shorter wavelengths, and precise synchronization of the x-ray pulse with seed laser systems. We describe an FEL facility concept based on a high repetition rate RF photocathode gun, that would allow simultaneous operation of multiple independent FEL's, each producing high average brightness, tunable over the VUV-soft x-ray range, and each with individual performance characteristics determined by the configuration of the FEL. SASE, enhanced-SASE (ESASE), seeded, harmonic generation, and other configurations making use of optical manipulations of the electron beam may be employed, providing a wide range of photon beam properties to meet varied user demands.
Date: June 24, 2007
Creator: Corlett, J.; Byrd, J.; Fawley, W.M.; Gullans, M.; Li, D.; Lidia,S.M. et al.
Partner: UNT Libraries Government Documents Department

The perpendicular electron energy flux driven by magnetic fluctuations in the edge of TEXT-U

Description: A fast bolometer was used for direct measurements of parallel electron energy flux in the edge of TEXT-U. The fluctuating component of the parallel electron energy flux, combined with a measurement of magnetic fluctuations, provides an upper limit to the perpendicular electron flux. This magnetically driven energy flux cannot account for the observed energy flux.
Date: June 12, 1995
Creator: Fiksel, G.; Prager, S.C.; Bengtson, R.D. & Wootton, A.J.
Partner: UNT Libraries Government Documents Department

Preliminary comparison of monolithic and aperture optics for XRMF

Description: Comparisons between standard aperture optics and a custom designed monolithic capillary x-ray optic for the Kevex Omicron are presented. The results demonstrate the feasibility of retrofitting an Omicron with a monolithic capillary. Increased flux is observed especially at lower energies which results in an increase in sensitivity and potentially an increase in spatial resolution. Alignment is a critical factor in achieving optimal performance of the monolithic capillary. Further improvements in flux output, spot size and overall sensitivity are expected with better alignment.
Date: August 1, 1997
Creator: Havrilla, G.J. & Worley, C.G.
Partner: UNT Libraries Government Documents Department

Results from GROCSE I: A real-time search for gamma ray burst optical counterparts

Description: The GROCSE I experiment (Gamma-Ray Optical Counterpart Search Experiment) is a rapid slewing wide field of view optical telescope at Lawrence Livermore National Laboratory which responds to triggers from the BATSE GRB data telemetry stream that have been processed and distributed by the BACODINE network. GROCSE 1 has been in continuous automated operation since January 1994. As of October 1995, sky images for 22 GRB triggers have been recorded, in some cases while the burst was still emitting gamma rays. The preliminary analysis of eight of these events are presented here. No optical counterparts have yet been detected. Limits for optical emission are given.
Date: October 27, 1995
Creator: Lee, B.; Akerlof, C. & Ables, E.
Partner: UNT Libraries Government Documents Department

Long-term energetic-particle databases from geosynchronous and GPS orbits

Description: The Los Alamos National Laboratory has flown thirteen energetic particle instruments on geosynchronous satellites since 1976 and on seven GPS satellites since 1983. These instruments measure electrons and protons over a wide range of energies. The various instruments and the particles and energies that they measure are described. The measured fluxes are stored at Los Alamos in several databases that are available to outside users.
Date: March 1, 1998
Creator: Reedy, R.C.; Belian, R.D. & Clayton, T.E.
Partner: UNT Libraries Government Documents Department

ICRCCM phase II: Verification and calibration of radiation codes in climate models. Final report, 1 May 1990--30 April 1993

Description: Following the finding by the InterComparison of Radiation Codes used in Climate Models (ICRCCM) of large differences among fluxes predicted by sophisticated radiation models that could not be sorted out because of the lack of a set of accurate atmospheric spectral radiation data measured simultaneously with the important radiative properties of the atmosphere, the team of scientists proposed to remedy the situation by carrying out a comprehensive program of measurement and analysis called SPECTRE (Spectral Radiance Experiment). SPECTRE was to establish an absolute standard against which to compare models, and aimed to remove the hidden variables (unknown humidities, aerosols, etc.) which radiation modelers had invoked to excuse disagreements with observation. The data collected during SPECTRE were to form the test bed for the second phase of ICRCCM, namely verification and calibration of radiation codes used in climate models. This should lead to more accurate radiation models for use in parameterizing climate models, which in turn play a key role in the prediction of trace-gas greenhouse effects. This report summarizes the activities during the project`s Third year to meet stated objectives. The report is divided into three sections entitled: (1) SPECTRE Activities, (2) ICRCCM Activities, and (3) Summary Information. The section on SPECTRE activities summarizes the field portion of the project during 1991, and the data reduction/analysis performed by the various participants. The section on ICRCCM activities summarizes their initial attempts to select data for distribution to ICRCCM participants and at comparison of observations with calculations as will be done by the ICRCCM participants. The Summary Information section lists data concerning publications, presentations, graduate students supported, and post-doctoral appointments during the project.
Date: December 31, 1993
Creator: Ellingson, R.G.; Wiscombe, W.J.; Murcray, D.; Smith, W. & Strauch, R.
Partner: UNT Libraries Government Documents Department

Site scientific mission plan for the southern Great Plains CART site, January--June 1998

Description: The Southern Great Plains (SGP) Cloud and Radiation Testbed (CART) site is designed to help satisfy the data needs of the Atmospheric Radiation Measurement (ARM) Program Science Team. The primary purpose of this site scientific mission plan is to provide guidance for the development of plans for site operations. It also provides information on current plans to the ARM functional teams (Management Team, Data and Science Integration Team, Operations Team, and Instrument Team) and serves to disseminate the plans more generally within the ARM Program and among the members of the Science Team. This document includes a description of the operational status of the site and the primary site activities envisioned, together with information concerning approved and proposed intensive observation periods (IOPs). The primary users of this document are the Site operator, the Site Scientist Team (SST), the Science Team through the ARM Program science director, the ARM Program Experiment Center, and the aforementioned ARM Program functional teams. This plan is a living document that is updated and reissued every six months as the observational facilities are developed, tested, and augmented and as priorities are adjusted in response to developments in scientific planning and understanding.
Date: January 1, 1998
Creator: Peppler, R.A.; Lamb, P.J. & Sisterson, D.L.
Partner: UNT Libraries Government Documents Department