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Count rate performance of a microchannel plate photomultiplier

Description: The count rate dependent gain change of a microchannel plate photomultiplier has been measured. Gain changes of 60% have been observed for count rates in excess of 2 x 10/sup 5/ s/sup -1/. The microchannel plate photomultiplier was used as a multiplying element of a scintillation detector system using NaI(Tl) as the scintillator. Data are compared to a simplified model of this form of photomultiplier.
Date: January 1, 1981
Creator: Nieschmidt, E.B.; Lawrence, R.S.; Gentillon, C.D. & Vegors, S.H. Jr.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Area detectors for neutron protein crystallography

Description: The main problem in neutron protein crystallography is the low flux of present reactor based or pulsed neutron sources. This low flux is however well matched with presently available multiwire area detectors. One way to increase the flux at the sample is to increase the wavelength bandwidth. The conventional technique uses a monochromator with a bandwidth of the order of 1%. This bandwidth can be increased by using a multilayer monochromator composed of different ``d`` spacings. This provides a… more
Date: October 1, 1992
Creator: Schoenborn, B. P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Calibration and performance of a secondary emission chamber as a beam intensity monitor

Description: We report on a study of the behavior of a secondary emission chamber (SEC). We show the dependence of the SEC signal on the charge and velocity of the primary beam for beams of protons, and heavy ions including Helium, Neon, Chlorine and Iron. We fill the SEC with a selection of different gases including Hydrogen, Helium, Nitrogen, Argon, and air, studying the SEC response when it is acting as an ion chamber. We also investigate the behavior of the SEC at intermediate pressures between 10{sup -… more
Date: March 28, 2011
Creator: Sivertz, M.; Chiang, I-H, & Rusek, A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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High energy resolution x-ray spectrometer for high count rate XRF applications

Description: A new x-ray spectrometer has been constructed which incorporates a novel large area, low capacitance Si(Li) detector and a low noise JFET (junction field effect transistor) pr- eamplifier. The spectrometer operates at high count rates without the conventional compromise in energy resolution. For example, at an amplifier peaking time of 1 {mu}sec and a throughput count rate of 145,000 counts sec{sup {minus}1}, the energy resolution at 5.9 key is 220 eV FWHM. Commercially available spectrometers … more
Date: August 1, 1993
Creator: Rossington, C. S.; Madden, N. W. & Chapman, K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Statistical data filtration in neutron coincidence counting

Description: We assessed the effectiveness of statistical data filtration to minimize the contribution of matrix materials in 200-{ell} drums to the nondestructive assay of plutonium. Those matrices were examined: polyethylene, concrete, aluminum, iron, cadmium, and lead. Statistical filtration of neutron coincidence data improved the low-end sensitivity of coincidence counters. Spurious data arising from electrical noise, matrix spallation, and geometric effects were smoothed in a predictable fashion by th… more
Date: November 1, 1992
Creator: Beddingfield, D. H. & Menlove, H. O.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Event matrix system. [To eliminate high-rate backgrounds]

Description: The number of background events in nuclear and particle physics experiments which use multiwire proportional chambers can be extremely high. Using a computer to resolve these events results in a high deadtime for the experiment. A fast matrix system for decreasing the number of background events is described in this report. 4 figures.
Date: March 1, 1978
Creator: Dalton, C.G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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High accuracy gaseous x-ray detectors

Description: An outline is given of the design and operation of high accuracy position-sensitive x-ray detectors suitable for experiments using synchrotron radiation. They are based on the gas proportional detector, with position readout using a delay line; a detailed examination is made of factors which limit spatial resolution. Individual wire readout may be used for extremely high counting rates.
Date: November 1, 1983
Creator: Smith, G.C.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Observation of Strong Resonant Behavior in the Inverse Photoelectron Spectroscopy of Ce Oxide

Description: X-ray Emission Spectroscopy (XES) and Resonant Inverse Photoelectron Spectroscopy (RIPES) have been used to investigate the photon emission associated with the Ce3d5/2 and Ce3d3/2 thresholds. Strong resonant behavior has been observed in the RIPES of Ce Oxide near the 5/2 and 3/2 edges. Inverse Photoelectron Spectroscopy (IPES) and its high energy variant, Bremstrahlung Isochromat Spectroscopy (BIS), are powerful techniques that permit a direct interrogation of the low-lying unoccupied electron… more
Date: December 15, 2009
Creator: Tobin, J G; Yu, S W; Chung, B W; Waddill, G D; Damian, E; Duda, L et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Triggering at high luminosity: fake triggers from pile-up

Description: Triggers based on a cut in transverse momentum (p/sub t/) have proved to be useful in high energy physics both because they indicte that a hard constituent scattering has occurred and because they can be made quickly enough to gate electronics. These triggers will continue to be useful at high luminosities if overlapping events do not cause an excessive number of fake triggers. In this paper, I determine if this is indeed a problem at high luminosity machines.
Date: January 1, 1983
Creator: Johnson, R.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Improvements in the energy resolution and high-count-rate performance of bismuth germanate

Description: Several methods for improving the energy resolution of bismuth germanate (BGO) have been investigated. It is shown that some of these methods resulted in a substantial improvement in the energy resolution. In addition, a method to improve the performance of BGO at high counting rates has been systematically studied. The results of this study are presented and discussed.
Date: January 1, 1985
Creator: Koehler, P. E.; Wender, S. A. & Kapustinsky, J. S.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Recent improvements to RC-line encoded position-sensitive proportional counters

Description: Continuing research on the principles of position encoding with RC lines has advanced the design of position-sensitive proportional counters (PSPCs) to meet the requirements for high count rates (>10/sup 5/ counts/sec) and good spatial resolution (>10/sup 4/ spatial elements) in small-angle scattering experiments with x rays and neutrons. Low-noise preamplifiers were developed with pole-zero cancellation in the feedback circuit and modular linear amplifiers with passive RCL shaping which, compa… more
Date: January 1, 1977
Creator: Borkowski, C. J. & Kopp, M. K.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Measurement of energy loss in the region of relativistic rise for particle identification

Description: The following boundary conditions are desirable for particle detectors providing momentum and mass measurement in a magnetic field. A multilayer drift chamber of the socalled ''bicycle'' type with a radius of 1.5 m is considered. The useful track length will be l/sub min/ = 1.3 m for a straight track at 90/sup 0/ to the beam axis. Two examples for possible subdivisions of this volume are chosen: (1) number of layers, n = 200 and thickness/layer, x = 6.5 mm; and (2) n = 56 and x = 23 mm. An anal… more
Date: January 1, 1977
Creator: Fischer, J.; Okuno, H. & Walenta, A.H.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Design study of a time of flight small-angle diffractometer for a pulsed neutron source

Description: The design study for a neutron SAS instrument at Argonne's proposed Intense Pulsed Neutron Source (peak thermal neutron flux 10/sup 16/ n/cm/sup 2/-sec) indicates that an effective high-resolution TOF SAS diffractometer can be constructed. The design features include a converging slit collimator, provision for 5 x 5 cm/sup 2/ sample cross sectional area, and a 1 x 1 m/sup 2/, two-dimensional detector. The fractional wavelength resolution of the instrument is negligibly small for all wavelengths… more
Date: January 1, 1977
Creator: Carpenter, J.M. & Faber, J. Jr.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Signal processing for semiconductor detectors

Description: A balanced perspective is provided on the processing of signals produced by semiconductor detectors. The general problems of pulse shaping to optimize resolution with constraints imposed by noise, counting rate and rise time fluctuations are discussed.
Date: February 1, 1982
Creator: Goulding, F. S. & Landis, D. A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Bayesian Methods for Radiation Detection and Dosimetry

Description: We performed work in three areas: radiation detection, external and internal radiation dosimetry. In radiation detection we developed Bayesian techniques to estimate the net activity of high and low activity radioactive samples. These techniques have the advantage that the remaining uncertainty about the net activity is described by probability densities. Graphs of the densities show the uncertainty in pictorial form. Figure 1 below demonstrates this point. We applied stochastic processes for a… more
Date: September 29, 2002
Creator: Groer, Peter G.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Influence of materials and counting-rate effects on /sup 3/He neutron spectrometry

Description: The high energy resolution of the Cuttler-Shalev /sup 3/He neutron spectrometer causes spectral measurements with this instrument to be strongly susceptible to artifacts caused by the presence of scattering or absorbing materials in or near the detector or the source, and to false peaks generated by pileup coincidences of the rather long-risetime pulses from the detector. These effects are particularly important when pulse-height distributions vary over several orders of magnitude in count rate… more
Date: January 1, 1984
Creator: Evans, A.E.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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Positron imaging with multiwire proportional chamber-gamma converter hybrid detectors

Description: A large area positron camera was developed using multiwire proportional chambers as detectors and electromagnetic delay lines for coordinate readout. Honeycomb structured gamma converters made of lead are coupled to the chambers for efficient gamma detection and good spatial resolution. Two opposing detectors, each having a sensitive area of 48 cm x 48 cm, are operated in coincidence for the detection of annihilation gammas (511 keV) from positron emitters. Detection efficiency of 4.2 percent p… more
Date: September 1, 1976
Creator: Chu, D. Y. H.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
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Position-sensitive gas proportional chambers

Description: A number of multiwire, position-sensitive, gas proportional chambers have been constructed which use fast delay line (2.5 ns/cm) readouts to provide trajectory position and angle information for particles near the focal planes of the Energetic Pion Channel and Spectrometer (EPICS) and High Resolution Spectrometer (HRS) at the Clinton P. Anderson Meson Physics Facility (LAMPF). These chambers are two dimensional with anode wires in one direction and cathode wires in the other direction. When ope… more
Date: January 1, 1977
Creator: Morris, C.L.; Hoffmann, G.W. & Thiessen, H.A.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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PWCs and drift chambers at ISABELLE

Description: Rate effects in proportional chambers and drift chambers are addressed first. The widely used high-gas-gain chambers would have impaired performance at ISABELLE data rates. Improvement can be expected with lower gas gain, and this possibility is investigated with respect to position and time resolution. Results on chamber lifetime are summarized; space-charge effects, gain saturation, and radiation hardness of electronics are considered. The resolution of drift chambers is discussed in some det… more
Date: January 1, 1978
Creator: Okuno, H.; Teramoto, Y. & Wheeler, C.D.
Item Type: Refine your search to only Report
Partner: UNT Libraries Government Documents Department
open access

Area detectors for neutron protein crystallography

Description: The main problem in neutron protein crystallography is the low flux of present reactor based or pulsed neutron sources. This low flux is however well matched with presently available multiwire area detectors. One way to increase the flux at the sample is to increase the wavelength bandwidth. The conventional technique uses a monochromator with a bandwidth of the order of 1%. This bandwidth can be increased by using a multilayer monochromator composed of different d'' spacings. This provides a l… more
Date: January 1, 1992
Creator: Schoenborn, Benno P.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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