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Radioisotope detection with accelerators

Description: High energy mass spectrometry is a new and very sensitive technique of measuring rare radioisotopes. This paper describes the techniques used to select and identify the individual radioisotope atoms in a sample and the status of the radioisotope measurements and their applications.
Date: December 1, 1979
Creator: Mast, T.S.; Muller, R.A. & Tans, P.P.
Partner: UNT Libraries Government Documents Department

Status of Compton recoil gamma-ray spectroscopy

Description: The gamma-ray component of the reactor radiation field can produce effects which impact strongly upon reactor design, shielding, and safety. Radiation effects arising from the gamma-ray component are induced by interaction of the absolute gamma-ray energy spectrum in the reactor environment. Hence, the most fundamental quantity underlying effects produced by the reactor gamma-ray field is the absolute gamma-ray energy continuum. To this end, the current status of Compton recoil gamma-ray spectrometry in Light Water Reactors (LWR) and Fast Breeder Reactors (FBR) environments is described. Particular emphasis is given to continuous gamma spectometry experiments in a LWR pressure vessel mockup at the Oak Ridge National Laboratory Poolside Critical Assembly (PCA). Gamma spectrometry plans for FBR environments are outlined with special attention placed on start-up experiments in the Fast Test Reactor (FTR). Improvements in Compton recoil gamma-ray spectroscopy are presented.
Date: May 1, 1979
Creator: Gold, R. & Kaiser, B.J.
Partner: UNT Libraries Government Documents Department

Detection limits for radioanalytical counting techniques

Description: In low-level radioanalysis it is usually necessary to test the sample net counts against some ''Critical Level'' in order to determine if a given result indicates detection. This is an interpretive review of the work by Nicholson (1963), Currie (1968) and Gilbert (1974). Nicholson's evaluation of three different computational formulas for estimation of the ''Critical Level'' is discussed. The details of Nicholson's evaluation are presented along with a basic discussion of the testing procedures used. Recommendations are presented for calculation of confidence intervals, for reporting of analytical results, and for extension of the derived formula to more complex cases such as multiple background counts, multiple use of a single background count, and gamma spectrometric analysis. (auth)
Date: June 1, 1975
Creator: Hartwell, J. K.
Partner: UNT Libraries Government Documents Department

Pneumatic system for transferring radioactive samples

Description: A pneumatic sample transfer system has been installed at the Savannah River Laboratory. Radioactive liquid samples are transferred from inside a shielded research cell to a shielded analytical chemistry cell 125 meters away. Samples are drawn into 4-mL glass vials which are sealed in polyethylene capsules. The capsules are propelled by compressed air at high speed through a 1-inch polyethylene tube. Equipment is provided for sealing and opening the polyethylene transfer capsules. The system has operated for 12 months, and 500 samples have been transferred successfully.
Date: January 1, 1979
Creator: Carpenter, J.A.
Partner: UNT Libraries Government Documents Department

Three-stage mass spectrometer for isotopic analysis of radionuclides in environmental samples

Description: A three-stage mass spectrometer was constructed for isotopic analysis of several radioactive as well as stable elements at environmental levels. The spectrometer is interfaced to a digital computer, which controls the operation of the spectrometer, accumulates data, reduces data, and prints a final result. The spectrometer has demonstrated the capability of measuring the isotopic composition of plutonium samples as small as 0.005 picogram and has an abundance sensitivity greater than 10/sup 8/.
Date: September 1, 1981
Creator: Halverson, J.E.
Partner: UNT Libraries Government Documents Department

GAMIDENT: a program to aid in the identification of unknown materials by gamma-ray spectroscopy

Description: A computer code, called GAMIDENT, was written to help identify isotopes by their gamma-ray emissions and thus to assist in the non-destructive assay of unknown materials. The program searches a file (called GAMIN) of gamma-ray spectra, from both radioactive decays and neutron captures, for matches with observed photon energies. This report describes the search procedure used, outlines the use of the code, and gives examples. The code is designed for operation at the Lawrence Livermore Laboratory on a CDC-7600 computer. It is written in standard Fortran (ANSI) as much as possible, but it contains some LRLTRAN instructions required to make use of the Livermore Timesharing System. The code uses about 30,000 words of SCM and about 550,000 words of LCM. Typical problems run in less than 30 seconds. The source program and the data file are available on request.
Date: January 4, 1980
Creator: Howerton, R.J. & Eggens, C.J.
Partner: UNT Libraries Government Documents Department

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

Description: 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 for electrons. Energy deposition in the sample by X rays is 10/sup -3/ to 10/sup -4/ less than for electrons for the same detectable concentration. High-brightness storage rings, especially in the 6 GeV class with undulators, will be approximately 10/sup 3/ brighter in the X-ray energy range from 5 keV to 35 keV than existing storage rings and provide for X-ray microprobes that are as bright as the most advanced electron probes. Such X-ray microprobes will produce unprecedented low levels of detection in diffraction, EXAFS, Auger, and photoelectron spectroscopies for both chemical characterization and elemental identification. These major improvements in microcharacterization capabilities will have wide-ranging ramifications not only in materials science but also in physics, chemistry, geochemistry, biology, and medicine.
Date: March 17, 1984
Creator: Sparks, C.J. Jr.
Partner: UNT Libraries Government Documents Department

Reliability of contemporary data-acquisition techniques for LEED analysis

Description: It is becoming clear that one of the principal limitations in LEED structure analysis is the quality of the experimental I-V profiles. This limitation is discussed, and data acquisition procedures described, which for simple systems, seem to enhance the quality of agreement between the results of theoretical model calculations and experimental LEED spectra. By employing such procedures to obtain data from Cu(100), excellent agreement between computed and measured profiles has been achieved. 7 figures.
Date: October 1, 1980
Creator: Noonan, J.R. & Davis, H.L.
Partner: UNT Libraries Government Documents Department

X-ray fluorescence cross sections for K and L x rays of the elements

Description: X-ray fluorescence cross sections are calculated for the major x rays of the K series 5 less than or equal to Z less than or equal to 101, and the three L series 12 less than or equal to Z less than or equal to 101 in the energy range 1 to 200 keV. This calculation uses Scofield's theoretical partical photoionization cross sections, Krause's evaluation of fluorescence and Coster-Kronig yields, and Scofield's theoretical radiative rates. Values are presented in table and graph format, and an estimate of their accuracy is made. The following x rays are considered: K..cap alpha../sub 1/, K..cap alpha../sub 1/,/sub 2/, K..beta../sub 1/, K..beta../sub 1/,/sub 3/, L..cap alpha../sub 1/, L..cap alpha../sub 1/,/sub 2/, L..beta../sub 1/, L..beta../sub 2/,/sub 15/, L..beta../sub 3/, Ll, L..gamma../sub 1/, L..gamma../sub 4/, and L/sub 1/ ..-->.. L/sub 2/,/sub 3/. For use in x-ray fluorescence analysis, K..cap alpha.. and L..cap alpha.. fluorescence cross sections are presented at specific energies: TiK identical with 4.55 keV, CrK identical with 5.46 keV, CoK identical with 7.00 keV, CuK identical with 8.13 keV, MoK..cap alpha.. identical with 17.44 keV, AgK identical with 22.5 keV, DyK identical with 47.0 keV, and /sup 241/Am identical with 59.54 keV. Supplementary material includes fluorescence and Coster--Kronig yields, fractional radiative rates, fractional fluorescence yields, total L-shell fluorescence cross sections, fluorescence and Coster-Kronig yields in condensed matter, effective fluorescence yields, average L-shell fluorescence yield, L-subshell photoionization cross section ratios, and conversion factors from barns per atom to square centimeters per gram.
Date: June 1, 1978
Creator: Krause, M.O.; Nestor, C.W. Jr.; Sparks, C.J. Jr. & Ricci, E.
Partner: UNT Libraries Government Documents Department

Neutron Techniques in Safeguards

Description: An essential part of Safeguards is the ability to quantitatively and nondestructively assay those materials with special neutron-interactive properties involved in nuclear industrial or military technology. Neutron techniques have furnished most of the important ways of assaying such materials, which is no surprise since the neutronic properties are what characterizes them. The techniques employed rely on a wide selection of the many methods of neutron generation, detection, and data analysis that have been developed for neutron physics and nuclear science in general.
Date: January 1, 1982
Creator: Zucker, M. S.
Partner: UNT Libraries Government Documents Department

Calibration of plutonium NDA by calorimetric assay

Description: The calorimetric assay of plutonium is an established and documented technique used extensively in DOE facilities for accountability measurements. Multilaboratory studies have quantified an average bias of <0.2% for the calorimetric assay of a wide range of plutonium bearing materials and plutonium isotopic compositions. This average bias can be reduced to <0.1% using new half-life values provided in independent studies by the U.S. Half-Life Evaluation Committee. An inspectors' verification program, utilizing calorimetric assay, has resulted in the increased use of calorimetric assay for calibration of plutonium nondestructive assay (NDA). The use of calorimetric assay as a standard reference methodology for improved plutonium NDA measurement control is recommended.
Date: January 1, 1978
Creator: Strohm, W.W.; Rodenburg, W.W.; Lemming, J.F.; Rogers, D.R. & Fellers, C.L.
Partner: UNT Libraries Government Documents Department

X-ray fluorescence capabilities for uranium ore analysis

Description: A rapid x-ray fluorescence (XRF) method for the quantitative analysis of uranium in ore and process samples is demonstrated. The method requires no uranium ore standards and provides a relative precision of +-2.5 percent. Particle-size and self-absorption effects are evaluated along with current methods of excitation and detection for M, L, and K series uranium x-rays. Sensitivities and detection limits are comparable using either energy dispersive or wavelength dispersive analysis of uranium L x-rays, and wavelength dispersive analysis of uranium M x-rays for both thick and thin samples. The XRF methods are more sensitive than the analysis of uranium by /sup 252/Cf neutron-induced ..gamma..-ray analysis or by direct photon analysis of uranium daughters.
Date: August 1, 1977
Creator: Nielson, K K; Wogman, N A & Brodzinski, R L
Partner: UNT Libraries Government Documents Department

Survey of chemical speciation of trace elements using synchrotron radiation

Description: Information concerning the chemical state of trace elements in biological systems generally has not been available. Such information for toxic elements and metals in metalloproteins could prove extremely valuable in the elucidation of their metabolism and other biological processes. The shielding of core electrons by binding electrons affect the energy required for creating inner-shell holes. Furthermore, the molecular binding and the symmetry of the local environment of an atom affect the absorption spectrum in the neighborhood of the absorption edge. X-ray absorption near-edge structure (XANES) using synchrotron radiation excitation can be used to provide chemical speciation information for trace elements at concentrations as low as 10 ppM. The structure and position of the absorption curve in the region of an edge can yield vital data about the local structure and oxidation state of the trace element in question. Data are most easily interpreted by comparing the observed edge structure and position with those of model compounds of the element covering the entire range of possible oxidation states. Examples of such analyses are reviewed. 14 refs., 1 fig.
Date: January 1, 1985
Creator: Gordon, B.M.
Partner: UNT Libraries Government Documents Department

GAMIDEN: a program to aid in the identification of unknown materials by gamma-ray spectroscopy

Description: The intent of the computer code GAMIDEN is to help identify isotopes by their gamma-ray emissions and thus to assist in the nondestructive assay of unknown materials. From both radioactive decays and neutron captures, GAMIDEN searches GAMTOT78, a file of gamma-ray spectra, for matches with observed photon energies. This report describes the search procedure, outlines the use of the code, and gives an example. The code is designed to operate on the CRAY 1 computer at Lawrence Livermore National Laboratory (LLNL). It is written in standard Fortran (ANSI) for the most part but contains some LRLTRAN instructions to make use of the Livermore time-sharing system (LTSS). The code uses about 545,000 words of memory. Typical problems run in about 45 s. The source program and the data file are available on request.
Date: June 25, 1982
Creator: Howerton, R.J.
Partner: UNT Libraries Government Documents Department

GRPANL: a program for fitting complex peak groupings for gamma and x-ray energies and intensities

Description: GRPANL is a general-purpose peak-fitting program that calculates gamma-ray and x-ray energies and intensities from a given spectral region. The program requires that the user supply input information such as the first and last channels of the region, the channels to be used as pre- and post-region background, the system gain and zero-intercept, and a list of approximate energy values at which peaks occur in the region. Because the peak position and peak-shape parameters enter nonlinearly into the peak-fitting algorithm, an iterative least-square procedure is used in the fitting process. The program iterates until either all convergence criteria are met or ten iterations have elapsed. The code described here allows for twenty free parameters and a region as large as 240 data channels. This code runs on an LSI-11 computer with 32K memory and disk-storage capability.
Date: January 1, 1980
Creator: Gunnink, R. & Ruhter, W.D.
Partner: UNT Libraries Government Documents Department

Nuclear chemistry counting facilities: requirements definition

Description: In an effort to upgrade outdated instrumentation and to take advantage of current and imminent technologies the Nuclear Chemistry Division at Lawrence Livermore Laboratory is about to undertake a major upgrade of their low level radiation counting and analysis facilities. It is expected that such a project will make a more coordinated data acquisition and data processing system, reduce manual data handling operations and speed up data processing throughput. Before taking on a systems design it is appropriate to establish a definition of the requirements of the facilities. This report examines why such a project is necessary in the context of the current and projected operations, needs, problems, risks and costs. The authors also address a functional specification as a prelude to a system design and the design constraints implicit in the systems implementation. Technical, operational and economic assessments establish necessary boundary conditions for this discussion. This report also establishes the environment in which the requirements definition may be considered valid. The validity of these analyses is contingent on known and projected technical, scientific and political conditions.
Date: April 5, 1979
Creator: O'Brien, D.W. & Baker, J.
Partner: UNT Libraries Government Documents Department

Biological trace element measurements using synchrotron radiation

Description: The feasibility of performing x-ray fluorescence trace element determinations at concentrations substantially below the ppM level for biological materials is demonstrated. Conditions for achieving optimum sensitivity were ascertained. Results achieved for five standard reference materials were, in most cases, in excellent agreement with listed values. Minimum detectable limits of 20 ppM were measured for most elements.
Date: July 1, 1985
Creator: Giauque, R.D.; Jaklevic, J.M. & Thompson, A.C.
Partner: UNT Libraries Government Documents Department

Quantitative determination of minerals in Nevada Test Site samples by x-ray diffraction

Description: The external standard intensity ratio technique has been developed into a routine procedure for quantitatively determining mineralogic compositions of Nevada Test Site (NTS) samples by x-ray diffraction. This technique used ratios of x-ray intensity peaks from the same run which eliminates many possible errors. Constants have been determined for each of thirteen minerals commonly found in NTS samples - quartz, montmorillonite, illite, clinoptilolite, cristobalite, feldspars, calcite, dolomite, hornblende, kaolinite, muscovite, biotite, and amorphous glass. Ratios of the highest intensity peak of each mineral to be quantified in the sample and the highest intensity peak of quartz are used to calculate sample composition. The technique has been tested on samples with three to eleven components representative of geologic environments at NTS, and is accurate to 7.0 wt % of the total sample. The minimum amount of each of these minerals detectable by x-ray diffraction has also been determined. QUANTS is a computer code that calculates mineral contents and produces a report sheet. Constants for minerals in NTS samples other than those listed above can easily be determined, and added to QUANTS at any time.
Date: July 1, 1983
Creator: Pawloski, G.A.
Partner: UNT Libraries Government Documents Department

Nondestructive assay system for use in decommissioning a plutonium-handling facility

Description: Argonne National Laboratory is decommissioning a facility used to fabricate reactor fuel elements. The equipment is contaminated with alpha emitters at levels up to 10/sup 12/ dpm/100 cm/sup 2/. The objective of decontamination is to reduce the TRU concentrations below 10 nCi/g of waste. A portable NDA procedure using NaI(T1) gamma-spectrometric techniques was selected to measure the residual Pu and /sup 241/Am in the glove boxes. Assays were performed at different stages in the decontamination process to estimate the detection system sensitivity and the effectiveness of the cleaning efforts.
Date: July 1, 1979
Creator: Roche, C.T.; Vronich, J.J.; Bellinger, F.O. & Perry, R.B.
Partner: UNT Libraries Government Documents Department

Empirical technique to measure x-ray production and detection efficiencies in the analytical electron microscope

Description: In the present work, a technique is proposed to experimentally measure the effective x-ray production and detection efficiency in pure element standards. This technique supplements and in some cases is preferable to the multi-element standard technique. Measurements of effective x-ray production and detection efficiencies are expected to be preferable to the standardless technique in cases where pure element samples can be prepared since the most uncertain parameters in the standardless technique are measured in the proposed technique.
Date: January 1, 1985
Creator: King, W.E.
Partner: UNT Libraries Government Documents Department