2,817 Matching Results

Search Results

Advanced search parameters have been applied.

in subjects: "Resolution"

open access

Picotron 100 streak tubes as a 150-channel photometer

The characterization of a streak camera based upon Picotron 100 tube types is given. Both a large (30 cm 1 x 10 cm dia.) and a small (18 cm 1 x 5 cm dia.) version of this design has been tested. Over 150 channels of information are simultaneously time resolved with system S.N.R. of 3 at 100 picosecond time resolution without post intensification. Absolute photometric evaluation is given in the dynamic mode, i.e. while operating in the picosecond time domain. Such quantitative data has been lack… more

Date: January 1, 1982

Creator: Majumdar, S.; Weiss, P.B. & Black, J.P.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

High-energy proton radiation damage of high-purity germanium detectors

Motivated by their applicability to gamma-ray spectroscopy experiments in space, quantitative studies of radiation damage effects in high-purity germanium detectors due to high-energy charged particles have been initiated with the irradiation by 6 GeV/c protons of two 1.0 cm thick planar detectors maintained at 88/sup 0/K. The threshold for resolution degradation and the annealing characteristics differs markedly from those previously observed for detectors irradiated by fast neutrons. Under pr… more

Date: October 1, 1977

Creator: Pehl, R.H.; Varnell, L.S. & Metzger, A.E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Energy dependence of metallic-encapsulated thermoluminescent dosimeters. Annual report

The gamma-ray energy responses of encapsulated /sup 7/LiF and CaF/sub 2/:Mn thermoluminescent dosimeters were measured and compred to calculated values. This study was performed in order to improve the accuracy of gamma-ray heating measurements made in polyenergetic gamma-ray fields such as Argonne National Laboratory's Zero Power Reactors. Equations used in the development of the TERC/III computer code and code input parameters are specified. A section on TLD precision is also included. Compar… more

Date: June 1980

Creator: Simons, G. G.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Simulation of hanging file experiments with CALOR89

This note presents the comparison of CALOR89 simulation with the hanging file'' test measurements conducted at Fermilab during the period of Sep 91--Jan 92. The purpose of this study is to benchmark CALOR89 code against the experimental data to enhance its reliability and predictive power. Seven hanging file configurations were simulated. The measured values of e/{pi} ratio (the ratio of electron to pion signal at the same energy), hadronic and electromagnetic resolutions were compared with the… more

Date: January 1, 1992

Creator: Job, P.K.; Price, L.E.; Proudfoot, J. (Argonne National Lab., IL (United States). High Energy Physics Div.); Handler, T. (Tennessee Univ., Knoxville, TN (United States)) & Gabriel, T.A. (Oak Ridge National Lab., TN (United States))

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Avalanche transistor pulser for fast-gated operation of micro-channel plate image-intensifiers

Transistors operated in the avalanche mode are employed to generate a 1000 volt 10 to 30 nsec wide pulse with less than 4 nsec rise and fall times. This pulse is resistively attenuated to approximately equal to 270 volts and drives the image intensifier tube which is a load of approximately equal to 200 pf. To reduce stray inductance and capacitance, transistor chips were assembled on a thick-film hybrid substrate. Circuit parameters, operating conditions, and coupling to the microchannel plate… more

Date: January 1, 1977

Creator: Lundy, A.; Parker, J. R.; Lunsford, J. S. & Martin, A. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

High resolution x-ray crystal spectrographs

Observation of x-ray line emissions are valuable for determining the thermodynamic state of the emitting plasma. For laser produced plasmas, diffraction crystals can be used to isolate x-ray monochromes to obtain high resolution spectral measurements. We will describe a versatile multi-crystal high resolution spectrograph used for photon energies from 0.5 to 6 keV. We will discuss a calculational package that tunes the response and sensitivity of the instrument and estimates the effect of sourc… more

Date: October 21, 1977

Creator: Koppel, L. N. & Eckels, J. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Surfaces and Thin Films Studied by Picosecond Ultrasonics

This research is the study of thin films and interfaces via the use of the picosecond ultrasonic technique. In these experiments ultrasonic waves are excited in a structure by means of a picosecond light pulse ( pump pulse''). The propagation of these waves is detected through the use of a probe light pulse that is time-delayed relative to the pump. This probe pulse measures the change {Delta}R(t) in the optical reflectivity of the structure that occurs because the ultrasonic wave changes the o… more

Date: May 1, 1992

Creator: Maris, J. H. & Tauc, J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Ultraviolet imaging of hydrogen flames

We have assembled an ultraviolet-sensitive intensified camera for observing hydrogen combustion by imaging the OH, A/sup 2/..sigma.. - X/sup 2//Pi/ bandhead emissions near 309 nm. The camera consists of a quartz and CaF achromat lense-coupled to an ultraviolet image intensifier which is in turn fiber-coupled to a focus projection scan (FPS) vidicon. The emission band is selected with interference filters which serve to discriminate against background. The camera provides optical gain of 100 to … more

Date: January 1, 1988

Creator: Yates, G. J.; Wilke, M. & King, N.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The Advanced Light Source U8 beam line, 20--300 eV

The U8 is a beam line under construction at the Advanced Light Source (ALS). The beam line will be described along with calculations of its performance and its current status. An 8 cm period undulator is followed by two spherical collecting mirrors, an entrance slit, spherical gratings having a 15{degree} deviation angle, a moveable exit slit, and refocusing and branching mirrors. Internal water cooling is provided to the metal M1 and M2 mirrors as well as to the gratings. Calculations have bee… more

Date: October 1, 1991

Creator: Heimann, P.; Warwick, T.; Howells, M.; McKinney, W.; Digennaro, D.; Gee, B. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

New newtron time-of-flight (NTOF) facilities at the Brookhaven 200-MeV Linac

The installation of a new beam chopper and radio-frequency quadrupole (RFQ) preinjector (750 keV) at the Brookhaven National Laboratory (BNL) 200-MeV Linac will enable single micropulse selection (pulse width <1 ns) with periods ranging from 400 ns to 10 ..mu..s. The standard micropulse intensity is 1.2 X 10/sup 9/ p..mu.. pulse with dc-average beam currents of 50 nA-1 ..mu..A routinely available. The NTOF facilities consists of 30-100 meter flight paths at angles of 0, 12, 30, 45, 90, and 135/… more

Date: January 1, 1988

Creator: Ward, T.E.; Alessi, J.; Brennan, J.; Grand, P.; Lankshear, R.; Snead, C.L. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Optical imaging diagnostics for fusion plasmas

Imaging diagnostics are used for spatially/emdash/and temporally/emdash/resolved quantitative measurements of plasma properties such as the ionization particle source, particle and energy loss, and impurity radiation in magnetically confined fusion plasmas. Diagnostics equipped with multi-element solid-state detectors (often with image intensifiers) are well suited to the environment of large fusion machines with high magnetic field and x-ray and neutron fluxes. We have both conventional (16msf… more

Date: April 1, 1988

Creator: Allen, S.L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Time-Resolved Doubly Bent Crystal X-Ray Spectrometer

X-ray spectroscopy is an essential tool in high temperature plasma research. We describe a time-resolved x-ray spectrometer suitable for measuring spectra in harsh environments common to many very high energy density laboratory plasma sources. The spectrometer consisted of a doubly curved Si(111) crystal diffraction element, a WL-1201 (ZnO:Ga) phosphor, a coherent fiber optic array, and two visible streak cameras. The spectrometer design described here has a minimum time resolution of 1.3 ns wi… more

Date: January 1, 1988

Creator: Hockaday, M. P.; Wilke, M. D.; Blake, R. L.; Vaninetti, J.; Gray, N. T. & Nedrow, P. T.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

FPS-vidicon television camras for ultrafast-scan data acquisition

Two ultrafast-scan (<8 ms/field) television (TV) camera prototypes have been developed for closed-circuit data-acquisition applications. The line and field rates are quasi-continuously adjustable. The number of lines, the integration duty cycle, and the scan direction are among the other adjustable parameters. Typical resolution at the fastest scan rate is >500 TV lines per picture height with a corresponding dynamic range (to light input) of more than 100. The cameras use the unique properties… more

Date: June 1, 1980

Creator: Noel, B. W. & Yates, G. J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

The Mark II Silicon Strip Vertex Detector and performance of a silicon detector telescope in the Mark II detector at the SLC

A Silicon Strip Vertex Detector (SSVD) consisting of 36 independent silicon detector modules has been built for use in the Mark II detector at the SLAC Linear Collider (SLC). We discuss the performance of the individual modules and the stability and accuracy of their placement in the mechanical support. To gain operational experience at the SLC, we have assembled and placed inside the Mark II a telescope made of three Silicon Detector Modules. We present results from the first data run of the S… more

Date: December 1, 1989

Creator: Labarga, L.; Adolphsen, C.; Gratta, G.; Litke, A.; Turala, M.; Zaccardelli, C. (California Univ., Santa Cruz, CA (USA). Inst. for Particle Physics) et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Comments on photoelectron spectroscopy of high- Tc 's

The photoemission discussion session during the Argonne conference on Fermiology of High-{Tc}'s provided a forum to air a number of unresolved issues in photoelectron spectroscopy. These are: (a) what is the exact energy dependence of the line width of the quasiparticle peaks: (b) are there any chemical potential shifts with hole doping; (c) why is a superconducting gap not observed in Y-123; and (d) different groups report different results in the band structure of Bi-2212. The first issue, wh… more

Date: January 1, 1991

Creator: Arko, A. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

High-resolution neutron transmission measurements on /sup 235/U, /sup 239/Pu, and /sup 238/U

High-resolution transmission measurements have been made on three sample thicknesses of both /sup 235/U and /sup 239/Pu at liquid nitrogen temperature and also on three of /sup 238/U at room temperature using neutrons from the water-moderated ORELA target. The data on /sup 235/U and /sup 239/Pu from 1 to 10,000 eV were obtained using /sup 6/Li glass scintillation detectors at 17.909-and 80.394-m flight paths. The /sup 238/U data from 1 to 100 keV were obtained using a new NE 110 proton-recoil s… more

Date: January 1, 1988

Creator: Harvey, J.A.; Hill, N.W.; Perey, F.G.; Tweed, G.L. & Leal, L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Recent developments in positron emission tomography (PET) instrumentation

This paper presents recent detector developments and perspectives for positron emission tomography (PET) instrumentation used for medical research, as well as the physical processes in positron annihilation, photon scattering and detection, tomograph design considerations, and the potentials for new advances in detectors. 117 refs., 4 figs., 4 tabs.

Date: April 1, 1986

Creator: Derenzo, S.E. & Budinger, T.F.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Soft x-ray transmission gratings

A technique was developed for producing transmission diffraction gratings suitable for use in the soft x-ray region. Thin self-supporting films of a transparent material are overlaid with several thousand opaque metallic strips per mm. Gratings with 2100, 2400, and 5600 1/mm have been produced and tested. Representative spectra over the wavelength range from 17.2 to 40.0 nm are given for a grating consisting of a 120-nm-thick Al support layer overlaid with 2400, 34-nm-thick, Ag strips/mm. The a… more

Date: January 1, 1980

Creator: Arakawa, E.T.; Caldwell, P.J. & Williams, M.W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Microscopy and Elemental Analysis in Tissue Samples Using Computed Microtomography With Synchrotron X-Rays

The initial development shows that CMT using synchrotron x-rays can be developed to ..mu..m spatial resolution and perhaps even better. This creates a new microscopy technique which is of special interest in morphological studies of tissues, since no chemical preparation or slicing of the sample is necessary. The combination of CMT with spatial resolution in the ..mu..m range and elemental mapping with sensitivity in the ppM range results in a new tool for elemental mapping at the cellular leve… more

Date: January 1, 1988

Creator: Spanne, P. & Rivers, M. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Atomic and molecular science with synchrotron radiation

This paper discusses the following topics: electron correlation in atoms; atomic innershell excitation and decay mechanisms; timing experiments; x-ray scattering; properties of ionized species; electronic properties of actinide atoms; total photon-interaction cross sections; and molecular physics. 66 refs. (LSP)

Date: November 7, 1989

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

General-purpose adaptive edge detector based on an empirical edge model

We present a new approach to computer edge detection for image mensuration. Our technique uses data from the actual image to build an edge-detector template for a matched filtering algorithm. We show that the procedure is superior to classical, template matching techniques for a computer-generated image and for a very noisy x-ray image.

Date: January 1, 1982

Creator: Breedlove, J.R. Jr. & Cantoni, V.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Precision programmable bipolar V/f instrumentation module

A precision bipolar voltage-to-frequency converter, which is computer-programmable from a digital interface, has been produced. Utilizing NIM packaging, the 1 MHz V/f has sixteen ranges and may be operated from panel controls as well as remotely programmed. Intended for use in magnetic measurements, good performance and versatility suggest wider application. The instrument is described and the circuit design is discussed in detail. Tests of the first unit are discussed and instrument specificat… more

Date: October 1, 1981

Creator: Hearn, W. E.; Green, M. I.; Nelson, D. H. & Rondeau, D. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

X-Ray microprobe characterization of materials: the case for undulators on advanced storage rings

The unique properties of X-rays offer many advantages over electrons and other charged particles for the microcharacterization of materials. X-rays are more efficient in exciting characteristic X-ray fluorescence and produce higher fluorescent signals to backgrounds than obtained with electrons. Detectable limits for X-rays are a few parts per billion and are 10/sup -3/ to 10/sup -5/ less than obtained with electrons. Energy deposition in the sample by X-rays is 10/sup -3/ to 10/sup -4/ less th… more

Date: January 1, 1985

Creator: Sparks, C.J. & Ice, G.E.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Results from beam tests of MEGA's low-mass, high-rate cylindrical MWPCs

One of the leading experimental projects at LAMPF has been the MEGA experiment. This is an experiment to search for the rare decay {mu} {yields} e{gamma} with a sensitivity of 10{sup {minus}13}. A prime component of this project has been the design and construction of high-rate, low mass MWPCs for the tracking of positrons from muon decay. With rate capabilities of 2 {times} 10{sup 4} e{sup +}/mm{sup 2}/s and a thickness of 3 {times} 10{sup {minus}4} radiation lengths, these chambers are state-… more

Date: January 1, 1991

Creator: Stanislaus, S.; Armijo, V.; Black, J. K.; Bolton, R. D.; Carius, S.; Cooper, M. D. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department