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The Early Optical Brightening in the GRB 071010B

Description: We report the detection of early (60-230 s) optical emission of the gamma-ray burst afterglow of GRB071010B. No significant correlation with the prompt {gamma}-ray emission was found. Our high time-resolution data combining with other measurements within 2 days after the burst indicate that GRB071010B is composed of a weak early brightening ({alpha} {approx} 0.6), probably caused by the peak frequency passing through the optical wavelengths, followed by a decay ({alpha} {approx} -0.51), attribu… more
Date: April 8, 2008
Creator: Wang, J. H.; Schwamb, M. E.; Huang, K. Y.; Wen, C. Y.; Zhang, Z. W.; Wang, S. Y. et al.
Partner: UNT Libraries Government Documents Department
open access

Isochronous Beamlines for Free Electron Lasers

Description: The transport systems required to feed a beam of highly relativistic electrons into a free electron laser have to satisfy very stringent requirements with respect to isochronicity and achromaticity. In addition, the line has to be tunable to match different operating modes of the free electron laser. Various beamlines emphasizing different aspects, such as quality of isochronicity and achromaticity, simplicity of the design, and space configurations are shown and compared. Solutions are present… more
Date: July 1, 1990
Creator: Berz, M.
Partner: UNT Libraries Government Documents Department
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Seventh international conference on time-resolved vibrational spectroscopy

Description: The International Conference on Time-Resolved Vibrational Spectroscopy (TRVS) is widely recognized as the major international forum for the discussion of advances in this rapidly growing field. The 1995 conference was the seventh in a series that began at Lake Placid, New York, 1982. Santa Fe, New Mexico, was the site of the Seventh International Conference on Time-Resolved Vibrational Spectroscopy, held from June 11 to 16, 1995. TRVS-7 was attended by 157 participants from 16 countries and 85 … more
Date: April 1, 1997
Creator: Dyer, R. B.; Martinez, M. A. D.; Shreve, A. & Woodruff, W. H.
Partner: UNT Libraries Government Documents Department
open access

TIME RESOLVED X-RAY SPOT DIAGNOSTIC

Description: A diagnostic was developed for the determination of temporal history of an X-ray spot. A pair of thin (0.5 mm) slits image the x-ray spot to a fast scintillator which is coupled to a fast detector, thus sampling a slice of the X-Ray spot. Two other scintillator/detectors are used to determine the position of the spot and total forward dose. The slit signal is normalized to the dose and the resulting signal is analyzed to get the spot size. The position information is used to compensate for smal… more
Date: April 26, 2005
Creator: Richardson, R.; Guethlein, G.; Falabella, S.; Chambers, F.; Raymond, B. & Weir, J.
Partner: UNT Libraries Government Documents Department
open access

On-chop processing for the wave union TDC implemented in FPGA

Description: The wave union TDC implemented in FPGA utilizes multiple measurement method to reach time resolution beyond the natural carry cell delay in FPGA. Lacking of analog compensation for bin width control available in ASIC, the wave union TDC takes the after-fact digital calibration approach. In addition to the temperature drift, non-uniformity of the carry chain structure in FPGA causes complicate differential nonlinearity pattern which imposes significant on-chip calibration challenge. In this pape… more
Date: May 1, 2009
Creator: Wu, Jinyan
Partner: UNT Libraries Government Documents Department
open access

Ultrafast scanning probe microscopy

Description: The authors have developed a general technique which combines the temporal resolution of ultrafast laser spectroscopy with the spatial resolution of scanned probe microscopy (SPM). Using this technique with scanning tunneling microscopy (STM), they have obtained simultaneous 2 ps time resolution and 50 {angstrom} spatial resolution. This improves the time resolution currently attainable with STM by nine orders of magnitude. The potential of this powerful technique for studying ultrafast dynamic… more
Date: January 1, 1994
Creator: Botkin, D.; Weiss, S.; Ogletree, D. F.; Salmeron, M. & Chemla, D. S.
Partner: UNT Libraries Government Documents Department
open access

Narrow Field of View Zenith Radiometer (NFOV) Handbook

Description: The two-channel narrow field-of-view radiometer (NFOV2) is a ground-based radiometer that looks straight up and measures radiance directly above the instrument at wavelengths of 673 and 870 nm. The field-of-view of the instrument is 1.2 degrees, and the sampling time resolution is one second. Measurements of the NFOV2 have been used to retrieve optical properties for overhead clouds that range from patchy to overcast. With a one-second sampling rate of the NFOV2, faster than almost any other AR… more
Date: November 1, 2008
Creator: Chiu, C.; Marshak, A.; Hodges, G.; Barnard, J. C. & Schmelzer, J.
Partner: UNT Libraries Government Documents Department
open access

Particle velocity measurements of the reaction zone in nitromethane

Description: The detonation reaction-zone length in neat, deuterated, and chemically sensitized nitromethane (NM) has been measured by using several different laser-based velocity interferometry systems. The experiments involved measuring the particle velocity history at a NM/PMMA (polymethylmethacrylate) window interface during the time a detonation in the NM interacted with the interface. Initially, Fabry-Perot interferometry was used, but, because of low time resolution (>5 ns), several different conf… more
Date: January 1, 2002
Creator: Sheffield, S. A. (Stephen A.); Engelke, R. P. (Raymond P.); Alcon, R. R. (Robert R.); Gustavsen, R. L. (Richard L.); Robbins, D. L. (David L.); Stahl, D. B. (David B.) et al.
Partner: UNT Libraries Government Documents Department
open access

Distributed Coincidence Circuit

Description: A coincidence circuit using the traveling wave principle as applied to distributed amplification is described. The resolving time is about 10{sup -8} sec. when the device is used in connection with scintillation detectors.
Date: June 28, 1950
Creator: Weigand, Clyde
Partner: UNT Libraries Government Documents Department
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Electron Bunch Characterization With Subpicosecond Resolution Using Electro-Optic Technique.

Description: In the past decade, the bunch lengths of electrons in accelerators have decreased dramatically and are in the range off a few millimeters. Measurement of the length as well as the longitudinal profile of these short bunches have been a topic of research in a number of institutions. One of the techniques uses the electric field induced by the passage of electrons in the vicinity of a birefringent crystal to change its optical characteristics. Well-established electro-optic techniques can then be… more
Date: June 11, 2001
Creator: Semertzidis, Y. K.; Castillo, V.; Larsen, R.; Lazarus, D. M.; Nikas, D.; Ozben, C. et al.
Partner: UNT Libraries Government Documents Department
open access

Atmospheric test models and numerical experiments for the simulation of the global distribution of weather data transponders

Description: A proposal has been made to establish a high density global network of atmospheric micro transponders to record time, temperature, and wind data with time resolution of {le} 1 minute, temperature accuracy of {+-} 1 K, spatial resolution no poorer than {approx}3km horizontally and {approx}0.1km vertically, and 2-D speed accuracy of {le} 1m/s. This data will be used in conjunction with advanced numerical weather prediction models to provide increases in the reliability of long range weather forec… more
Date: August 25, 1999
Creator: Grossman, A & Molenkamp, C R
Partner: UNT Libraries Government Documents Department
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Transient frequency-modulated spectroscopy: Application to the measurement of vector and scalar correlations in molecular photodissociation

Description: An intrinsically time-resolved version of frequency-modulation (FM) spectroscopy has been recently developed and applied to the study of gas-phase photodissociation dynamics. Transient FM spectroscopy allows low background detection of radical species with shot-noise limited sensitivities, time resolution sufficient for detection of collisionless photoproducts, and frequency resolution characteristic of single-mode cw lasers. Methods for the quantitative analysis of Doppler-broadened FM line sh… more
Date: April 1, 1998
Creator: North, S. W. & Hall, G. E.
Partner: UNT Libraries Government Documents Department
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Scientific program of the Advanced Light Source at LBL

Description: Construction of the Advanced Light Source (ALS) at the Lawrence Berkeley Laboratory is nearing completion, with operation as a US Department of Energy national user facility scheduled to begin in the spring of 1993. Based on a low-emittance, 1.5-GeV electron storage ring with 10 long straight sections available for insertion devices and, initially, 24 bend-magnet ports, the ALS will be a third-generation source of soft x-ray and ultraviolet (collectively, the XUV) synchrotron radiation. Experim… more
Date: October 1, 1991
Creator: Robinson, A. L. & Schlachter, A. S.
Partner: UNT Libraries Government Documents Department
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'Giant' multishell CdSe nanocrystal quantum dots with supporessed blinking: novel fluorescent probes for real-time detection of single-molecule events

Description: We reported for the first time that key nanocrystal quantum dot (NQD) optical properties-quantum yield, photobleaching and blinking-can be rendered independent ofNQD surface chemistry and environment by growth of a very thick, defect-free inorganic shell. Here, we show the precise shell-thickness dependence of these effects. We demonstrate that 'giant-shell' NQDs can be largely non-blinking for observation times as long as 54 minutes and lhat on-time fractions are independent of experimental ti… more
Date: January 1, 2009
Creator: Hollingsworth, Jennifer A; Vela, Javier; Htoon, Han; Klimov, Victor I; Casson, Amy R & Chen, Yongfen
Partner: UNT Libraries Government Documents Department
open access

Transistor Counting Systems for Scintillation Detectors

Description: The requirements for multiple-coincidence counting systems with 10{sup -8}- to 10{sup -9}-sec time resolution can be met economically with presently available high-frequency transistors. The design of solid-state coincidence circuits, amplitude discriminators, and decade scalers is considered and their operation discussed. Several systems have been designed utilizing up to 180 channels from scintillation detectors.
Date: February 17, 1960
Creator: Baker, Stanley C.; Jackson, Horace G. & Mack, Dick A.
Partner: UNT Libraries Government Documents Department
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Transient, Real-Time, Particulate Emission Measurements in Diesel Engines

Description: This paper reports our efforts to develop an instrument, TG-1, to measure particulate emissions from diesel engines in real-time. TG-1 while based on laser-induced incandescence allows measurements at 10 Hz on typical engine exhausts. Using such an instrument, measurements were performed in the exhaust of a 1.7L Mercedes Benz engine coupled to a low inertia dynamometer. Comparative measurements performed under engine steady state conditions showed the instrument to agree within {+-}12% of measu… more
Date: August 24, 2003
Creator: Gupta, S.; Shih, J.; Hillman, G.; Sekar, R.; Graze, R.; Shimpi, S. et al.
Partner: UNT Libraries Government Documents Department
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Trends in on-Road Vehicle Emissions of Ammonia

Description: Motor vehicle emissions of ammonia have been measured at a California highway tunnel in the San Francisco Bay area. Between 1999 and 2006, light-duty vehicle ammonia emissions decreased by 38 {+-} 6%, from 640 {+-} 40 to 400 {+-} 20 mg kg{sup -1}. High time resolution measurements of ammonia made in summer 2001 at the same location indicate a minimum in ammonia emissions correlated with slower-speed driving conditions. Variations in ammonia emission rates track changes in carbon monoxide more c… more
Date: July 15, 2008
Creator: Kean, A. J.; Littlejohn, D.; Ban-Weiss, G. A.; Harley, R. A.; Kirchstetter, T. W. & Lunden, M. M.
Partner: UNT Libraries Government Documents Department
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Testing of the scintillation sandwich prototype

Description: The 3 m{sup 2} prototype of the surface detector using optical fiber readout was completely prepared for testing measurements in February 1995 at Fermilab. Two 25 mm thick, 3 m{sup 2} acrylic scintillation plates (1.2 {times} 2.5 m{sup 2}) are used for light collection in the upper (above the 25 mm steel plate) and lower (below the steel) counters of the sandwich. The light is collected with the help of 1 mm diameter wavelength shifter fiber loops 3 m long inserted in the grooves on the top sur… more
Date: June 1, 1995
Creator: Vashkevich, V.
Partner: UNT Libraries Government Documents Department
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A laser strain gauge for accelerator targets.

Description: Multi megawatt accelerators can deliver sufficient power to a target to destroy it in a few pulses. In order to look at the response of solid and liquid targets under these high power pulses, we are developing optical methods of measuring surface deformations with time resolutions limited by laser pulse lengths. These methods can be used to examine the surfaces of solids and liquids during elastic deformation and unstable hydrodynamic flows. We present preliminary results of a system designed f… more
Date: July 17, 2001
Creator: Hassanein, A. & Norem, J.
Partner: UNT Libraries Government Documents Department
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