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Temperature evaluation of EMR's 510 PMT and ITT MCP PMT

Description: Neutron detectors for flight test applications use either a photomultiplier tube (PMT) or a silicon photodiode as a light detector to monitor the light output of scintillation materials. Silicon diodes lack sensitivity, so PMT's are used in most low flux neutron applications. The SA 1690 is presently the only Sandia qualified PMT. It has a complex temperature response requiring the selection of a temperature compensation circuit during assembly to meet accuracy requirements. Results are presented of a study which was performed to evaluate the temperature stability of two other light detectors and to compare the results with the performance of the SA 1690.
Date: February 1, 1979
Creator: Amaral, R.J.; Dolan, K.W. & Sundahl, R.O.
Partner: UNT Libraries Government Documents Department

Some electronic aspects of energy measurements with solid-state detectors

Description: The usual requirement for a spectrometer system is to provide the best energy resolution that can be obtained with a set of given experimental constraints. These constraints can change with each experiment, and the experimenter should be able to optimize the parameters of the spectrometer to obtain the best results. The detector, either silicon or germanium, is connected to a charge-sensitive preamplifier. The detector produces short current pulses of a width equal to the collection time of the detector. These are integrated by the charge-sensitive preamplifier which produces a voltage step at its output. The output step rise time is equal to the collection time of the detector, its amplitude is equal to the input charge divided by the capacitance of the feedback capacitor, and its decay time constant is determined by the preamplifier feedback components.
Date: April 1, 1977
Creator: Goulding, F.S. & Landis, D.A.
Partner: UNT Libraries Government Documents Department

Electro-optical streak camera system for use at 1. 3. mu. m

Description: An electro-optical streak camera for use at 1.3 ..mu..m is described, including determination of the streak tube absolute photocathode sensitivity and system dynamic range. Nonlinear response at higher input intensities suggests multi-photon photocathode absorption.
Date: January 1, 1979
Creator: Palmer, M.A. & Palmer, R.E.
Partner: UNT Libraries Government Documents Department

Computer-controlled neutron time-of-flight spectrometer. Part II

Description: A time-of-flight spectrometer for neutron inelastic scattering research has been interfaced to a PDP-15/30 computer. The computer is used for experimental data acquisition and analysis and for apparatus control. This report was prepared to summarize the functions of the computer and to act as a users' guide to the software system.
Date: December 1, 1979
Creator: Merriman, S.H.
Partner: UNT Libraries Government Documents Department

Design and performance of the new cathode readout proportional chambers in LASS

Description: The design and construction of a new proportional chamber system for the LASS spectrometer are discussed. This system consists of planar and cylindrical chambers employing anode wire and cathode strip readout techniques. The good timing characteristics of anode readout combine with the excellent spatial resolution of cathode readout to provide powerful and compact detectors. Preliminary resolution data are presented along with operating characteristics of the various devices.
Date: October 1, 1980
Creator: Aiken, G.; Aston, D. & Dunwoodie, W.
Partner: UNT Libraries Government Documents Department

Computer control for a cladding thickness tester

Description: A cladding thickness tester for extruded reactor fuel tubes has been automated to provide reduced operator interaction. The cladding thickness tester, which uses an x-ray fluorescence analyzer, has been interfaced with an SRL/6800 microcomputer to control fuel tube orientation, operate the analyzer, calculate cladding thickness, and give pertinent data in hardcopy tabular form.
Date: December 1, 1979
Creator: Sand, R.J.
Partner: UNT Libraries Government Documents Department

Results on the performance of a broad band focussing Cherenkov counter

Description: The field of ring imaging (broad band differential) Cherenkov detectors has become a very active area of interest in detector development at several high energy physics laboratories. Our group has previously reported on a method of Cherenkov ring imaging for a counter with large momentum and angular acceptance using standard photo multipliers. Recently, we have applied this technique to the design of a set of Cherenkov counters for use in a particle search experiment at Fermi National Accelerator Laboratory (FNAL). This new detector operates over the range 0.998 < ..beta.. < 1.000 in velocity with a delta..beta.. approx. 2 x 10/sup -4/. The acceptance in angle is +- 14 mrad in the horizontal and +- 28 mrad in the vertical. We report here on the performance of this counter.
Date: January 1, 1980
Creator: Cester, R.; Fitch, V.L.; Montag, A.; Sherman, S.; Webb, R.C. & Witherell, M.S.
Partner: UNT Libraries Government Documents Department

Energy-dependent losses in pulsed-feedback preamplifiers

Description: Energy dependent counting losses occur in most pulsed-feedback preamplifiers due to the loss of those pulses which activate the recharge system. A pulsed-feedback system that overcomes this inefficiency is described. Pulsed-light feedback as used with germanium gamma-ray spectrometers is discussed as used at high energies and high rates where those losses become significant. Experimental results are presented.
Date: November 1, 1978
Creator: Landis, D.A.; Madden, N.W. & Goulding, F.S.
Partner: UNT Libraries Government Documents Department

Noise considerations in millimeter-wave spectrometers

Description: An improved version of a microwave spectrometer operating in the vicinity of 70 GHz is described. The spectrometer, which incorporates a Fabry-Perot resonator and superheterodyne detection for high sensitivity is designed for the detection of gaseous pollutants and other atmospheric constituents. The instrument is capable of detecting polar molecules with absorption coefficients as small as 2 x 10/sup -9/cm/sup -1/. For sulphur dioxide diluted in air, this sensitivity corresponds to a detection limit of 1.2 ppm without preconcentration and with a time constant of 1 second. Measurements and analysis of the noise contributions limiting the sentivity are presented.
Date: December 1, 1978
Creator: Zoellner, W.D.; Kolbe, W.F. & Leskovar, B.
Partner: UNT Libraries Government Documents Department

Versatile pulse programmer for pulsed nuclear magnetic resonance spectroscopy

Description: A description of the sequence of events and the decisions leading to the design of a versatile pulse programmer for pulsed NMR are presented. Background and application information is discussed in order that the reader might better understand the role of the pulse programmer in a NMR spectrometer. Various other design approaches are presented as a basis for comparison. Specifications for this design are proposed, the hardware implementation of the specifications is discussed, and the software operating system is presented.
Date: May 1, 1979
Creator: Adduci, D. J.
Partner: UNT Libraries Government Documents Department

Microprocessor-controlled portable neutron spectrometer

Description: A neutron spectrometer that acquires and unfolds data in the field has been developed for use in the energy range from 1 to 20 MeV. The system includes an NE213 organic scintillation detector, automatic gain stabilization, automatically stabilized pulseshape discrimination, an LSl-11 microprocessor for control and data reduction, and a multichannel analyzer for data acquisition. The system, with the exception of the multichannel analyzer, is mounted in a suitcase 47 by 66 by 23.5 cm. The mass is 23.5 kg.
Date: August 29, 1979
Creator: Hunt, G.F.; Kaifer, R.C.; Slaughter, D.R.; Strout, R.E. II & Rueppel, D.W.
Partner: UNT Libraries Government Documents Department

Reactor gamma spectrometry: status

Description: Current work is described for Compton Recoil Gamma-Ray Spectrometry including developments in experimental technique as well as recent reactor spectrometry measurements. The current status of the method is described concerning gamma spectromoetry probe design and response characteristics. Emphasis is given to gamma spectrometry work in US LWR and BR programs. Gamma spectrometry in BR environments are outlined by focussing on start-up plans for the Fast Test Reactor (FTR). Gamma spectrometry results are presented for a LWR pressure vessel mockup in the Poolside Critical Assembly (PCA) at Oak Ridge National Laboratory (ORNL).
Date: January 1, 1979
Creator: Gold, R. & Kaiser, B. J.
Partner: UNT Libraries Government Documents Department

Experience using the 168/E microprocessor for off-line data analysis

Description: The 168/E is a SLAC developed microprocessor which emulates the IBM 360/370 computers with an execution speed of about one half of a IBM 370/168. These processors are used in parallel for the track finding and geometry programs of the LASS spectrometer. The system is controlled by a PDP-11 minicomputer via a three port interface which we call the Bermuda Triangle. The tape handling and downloading is controlled by one of SLAC's IBM computers via a SLAC built interface between the PDP-11 and an IBM channel. Initially, there will be a system of 6 168/E's which should be able to give six times the production capacity than can be attained by running production jobs on the SLAC Triplex system. The cost of the system, including the channel interface, is $120,000 and yet it yields the equivalent computer power of 3 IBM 370/168's. Hence, this system is an extremely cost-effective method for off-line data analysis.
Date: October 1, 1979
Creator: Kunz, P.F.; Fall, R.N.; Gravina, M.F.; Halperin, J.H.; Levinson, L.J.; Oxoby, G.J. et al.
Partner: UNT Libraries Government Documents Department

Resonance ionization mass spectrometry at Los Alamos National Laboratory

Description: We present recent results on the application of resonance ionization mass spectrometry to the precision measurement of isotope ratios, particularly in the presence of isobaric interferences. Emphasis is placed on hardware developments having the potential to increase ionization efficiency.
Date: January 1, 1983
Creator: Nogar, N.S.; Downey, S.W.; Keller, R.A. & Miller, C.M.
Partner: UNT Libraries Government Documents Department

A new chopper spectrometer for neutron Brillouin scattering and low-angle neutron inelastic scattering: PHAROS (Phase 1)

Description: Phase I of PHAROS, the new chopper spectrometer at LANSCE, is described in detail. The main components are a water moderator, a 60-Hz double-bladed T-zero chopper, a 600Hz magnetic-bearing Fermi chopper, a 6m-long vacuum vessel with thin aluminium-alloy vacuum window and a 1.2m[sup 2] array of linear position-sensitive detectors.
Date: January 1, 1993
Creator: Robinson, R.A.; Nutter, M.; Ricketts, R.L.; Larson, E.; Sandoval, J.P.; Lysaght, P. et al.
Partner: UNT Libraries Government Documents Department

Monte Carlo error analysis in x-ray spectral deconvolution

Description: The deconvolution of spectral information from sparse x-ray data is a widely encountered problem in data analysis. An often-neglected aspect of this problem is the propagation of random error in the deconvolution process. We have developed a Monte Carlo approach that enables us to attach error bars to unfolded x-ray spectra. Our Monte Carlo error analysis has been incorporated into two specific deconvolution techniques: the first is an iterative convergent weight method; the second is a singular-value-decomposition (SVD) method. These two methods were applied to an x-ray spectral deconvolution problem having m channels of observations with n points in energy space. When m is less than n, this problem has no unique solution. We discuss the systematics of non-unique solutions and energy-dependent error bars for both methods. The Monte Carlo approach has a particular benefit in relation to the SVD method: it allows us to apply the constraint of spectral non-negativity after the SVD deconvolution rather than before. Consequently we can identify inconsistencies between different detector channels. 4 references, 6 figures.
Date: January 1, 1984
Creator: Shirk, D.G. & Hoffman, N.M.
Partner: UNT Libraries Government Documents Department

The application of position-sensitive phoswich detectors for low-mass fragment detection in an array environment

Description: Large solid angle position-sensitive phoswich detectors have been constructed to replace smaller units in an array for detecting medium mass fragments (Z less than or equal to 15) in nuclear experiments. The position information was obtained from a time analysis method. 5 refs., 9 figs.
Date: September 1, 1988
Creator: Chan, Y.; Chavez, E.; Dacal, A.; Gazes, S.; Harmon, B.A.; Plagnol, E. et al.
Partner: UNT Libraries Government Documents Department

Bragg Curve Spectroscopy

Description: An alternative utilization is presented for the gaseous ionization chamber in the detection of energetic heavy ions, which is called Bragg Curve Spectroscopy (BCS). Conceptually, BCS involves using the maximum data available from the Bragg curve of the stopping heavy ion (HI) for purposes of identifying the particle and measuring its energy. A detector has been designed that measures the Bragg curve with high precision. From the Bragg curve the range from the length of the track, the total energy from the integral of the specific ionization over the track, the dE/dx from the specific ionization at the beginning of the track, and the Bragg peak from the maximum of the specific ionization of the HI are determined. This last signal measures the atomic number, Z, of the HI unambiguously.
Date: May 1, 1981
Creator: Gruhn, C.R.
Partner: UNT Libraries Government Documents Department

Ten channel filter-fluorescer spectrometer

Description: A ten channel filter-fluorescer spectrometer was designed for measuring x-ray spectra from 2 to 115 keV at the Argus and Shiva laser facilities. Previously x-ray spectra were measured with filtered detectors; however, the higher fluxes and more complicated spectra observed in recent experiments requires the greater photon energy definition of this technique. Five filter-detector channels are also incorporated in the spectrometer for measuring low intensity sources. Five Pb-filtered detectors will be used for obtaining spectral information for energies greater than 100 keV. Provisions are being made to automate this diagnostic to produce the x ray spectrum minutes after shot time.
Date: October 27, 1978
Creator: Pruett, B.L.; Tirsell, K.G.; Kornblum, H.N.; Glaros, S.S.; Campbell, D.E. & Slivinsky, V.W.
Partner: UNT Libraries Government Documents Department

Azimuthal spread of the avalanche in proportional chambers

Description: The angular distribution of the avalanche around the anode wire in the gas proportional counter is determined by measuring the distribution of positive ions arriving on cathode strips surrounding the anode wire for each single event. The shape and width of the distribution depend on such factors as the gas gain, the anode diameter, the counting gas and the primary ionization density. Effects of these factors are studied systematically, and their importance for practical counter applications is discussed.
Date: October 1, 1978
Creator: Okuno, H.; Fischer, J.; Radeka, V. & Walenta, A.H.
Partner: UNT Libraries Government Documents Department

Maximum information with minimum complexity from a coincidence assay system

Description: There are nuclear based assay situations where measurement of coincident radiation is possible and also appropriate because the coincidence requirement serves to decrease background and moreover may be particularly characteristic of the material being assayed. In these cases, besides the basic coincidence response, the coincidence system can be made to furnish additional useful information, to reduce the sensitivity of the measurement to detection efficiency, provide a continuous test of system performance, and in some instances, signal the presence of environmental noise or nuclear interferences. This paper discusses this coincidence system further. 3 refs., 1 fig.
Date: January 1, 1988
Creator: Zucker, M.S.
Partner: UNT Libraries Government Documents Department

Calibrations of a multichannel soft x-ray spectrometer

Description: A time resolved, 14 channel spectrometer with an absolutely calibrated response, was developed to cove an x-ray photon energy spectrum from 70 to 650 eV. The spectrometer utilized a combination of thin film prefilters, layered synthetic microstructure (LSM) diffractors, metal coated plastic scintillators, and photomultiplier detector tubes. Calibration of the spectrometer was done piecemeal for each component with standard techniques and the component calibrations were convolved to get a complete spectrometer response function. The two calibration procedures were compared.
Date: January 1, 1986
Creator: Blake, R.L.; Hockaday, R.G. & Grosso, J.S.
Partner: UNT Libraries Government Documents Department

Bismuth germanate's role in the new revolution in gamma-ray spectroscopy

Description: Some of the considerations on how to effectively incorporate bismuth germanate into complex detection systems are covered, and some of these new systems now in operation or under construction are discussed. Significant achievements in gamma ray spectroscopy are reviewed as well as some recent results based on data taken with coincidence arrays of germanium detectors and Compton-suppression spectrometers. Then the first impact of bismuth germanate detectors on our understanding of the properties of nuclei that have high energy and very high angular momentum states are addressed. (LEW)
Date: January 1, 1983
Creator: Johnson, N.R.; Baktash, C. & Lee, I.Y.
Partner: UNT Libraries Government Documents Department