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1

In-situ gamma spectrometry in environmental monitoring.  

PubMed

In-situ gamma spectrometry (scintillation or semiconductor) can be used effectively for monitoring natural and man-made radionuclide concentrations, together with the corresponding photon fields, in the environment and in workplaces. It is applied in operational and emergency monitoring of nuclear facilities, waste storage facilities and the uranium industry, in radioactive contamination measurements and mapping, environmental, radiohygienic and radiation safety studies, etc. Methods for processing and interpreting data, experimental techniques (ground or airborne arrangement), calibration and verification and examples of applications are discussed in this paper. PMID:20022255

Kluson, J

2009-11-26

2

In situ gamma-ray spectrometry for the measurement of uranium in surface soils  

Microsoft Academic Search

The application of the technique of in situ gamma-ray spectrometry to the measurement of uranium isotopes in surface soils is described. A basic review of the in situ methodology using high resolution germanium gamma-ray spectrometers is given and specifics on calculated fluences, dose rates in air, and calibration factors are provided for relevant uranium isotopes and their progeny. The influence

K. M. Miller; P. Shebell; G. A. Klemic

1994-01-01

3

Applications of in Situ gamma-Ray Spectrometry.  

National Technical Information Service (NTIS)

Gamma-ray spectrometric methods using high-resolution Ge(Li) and high purity Ge detectors have been used to quantify the concentrations and external exposure rates of radionuclides in the soil. These in situ methods have been used to study radionuclide de...

R. C. Ragaini J. A. Kirby

1978-01-01

4

Monitoring anthropogenic radioactivity in salt marsh environments through in situ gamma-ray spectrometry  

Microsoft Academic Search

Radionuclide bearing effluents discharged into the Irish Sea have resulted in the accumulation of radionuclides in salt marsh environments which can contribute to critical group exposures. Recent developments in in situ gamma-ray spectrometry provide a novel and effective method for monitoring anthropogenic radionuclide concentrations and distributions within these coastal environments. This paper presents the results from an in situ survey

Andrew N. Tyler

1999-01-01

5

The development and use of an in situ gamma-ray spectrometry system in North Wales  

Microsoft Academic Search

North Wales has a wide range of levels of natural radioactivity together with significant levels of artificial radionuclides on its coast arising mainly from the Sellafield nuclear processing plant. In situ gamma-ray spectrometry offers a rapid alternative to core sampling for mapping out these radioactivity levels but requires extensive calibration and some knowledge of the depth distribution. Quantitative in situ

J. Macdonald; P. H. Smith; D. J. Assinder

1996-01-01

6

Unfolding the response of a Ge detector used for in-situ gamma-ray spectrometry  

Microsoft Academic Search

In environmental radiation protection portable Ge detectors are used for in-situ gamma-ray spectrometry. In order to determine the complete photon fluence rate spectra including the continuum component due to photons scattered in the environment from measured pulse height distributions one needs to apply unfolding methods. A prerequisite of the unfolding is the knowledge of the response functions of the detector

Georg Fehrenbacher; Reinhard Meckbach; Peter Jacob

1996-01-01

7

Determination of depth distributions of natural radionuclides with in situ gamma-ray spectrometry  

Microsoft Academic Search

To determine natural and artificial radio-nuclide concentrations in the ground in situ gamma-ray spectrometry method based on assumptions on the depth distribution of the radionuclides. In this paper two-slab geometries with different activities are assumed and two methods to derive information on the depth distribution of natural radionuclides from the measured spectra are examined. They use the distribution dependence of

Severin Thummerer; Peter Jacob

1998-01-01

8

Rapid measurements of soil contamination after the Chernobyl accident in the Federal Republic of Germany by in-situ gamma-ray spectrometry  

Microsoft Academic Search

The method of in situ gamma ray spectrometry for measurements of soil surface contamination is described. The results of nuclide specific measurements of soil contamination in the Federal Republic of Germany after the Chernobyl reactor accident including exposure rate measurements of individual radionuclides are reported. A total of 22 artificial radionuclides could be detected. In the first days after the

I. Winkelmann; S. Weimer; S. Wolff; P. Neumann

1988-01-01

9

Assessment of natural and anthropogenic radioactivity levels in rocks and soils in the environs of Swieradow Zdroj in Sudetes, Poland, by in situ gamma-ray spectrometry  

Microsoft Academic Search

The natural radioactivity of 40K, 208Ti, 212Pb, 212Bi, 214Pb, 214Bi, 228Ac and the fallout of 137Cs in typical rocks and soils of ?wieradów Zdrój area (Sudetes Mountains, Poland) were measured in situ using a portable gamma-ray spectrometry workstation. The measurement points were chosen for different regional lithology: within hornfelses of the Szklarska Pore?ba schist-belt, quartz rocks, gneisses of the ?wieradów

D. Malczewski; L. Teper; J. Dorda

2004-01-01

10

Survey of the {sup 137}Cs contamination in Belgium by in-situ gamma spectrometry, a decade after the Chernobyl accident  

SciTech Connect

The residual radiocesium concentration, nearly 10 y after the Chernobyl accident, is measured at different sites on the Belgian territory by means of in-situ gamma-spectrometry. A possible link between the rainfall at the beginning of May 1986 and the actual cesium concentration is investigated. The radiological impact of this contamination, even in the most affected regions in the Ardennes, is very small (<6 {mu}Sv y{sup -1}). 6 refs., 4 figs., 1 tab.

Uyttenhove, J. [Univ. of Gent (Belgium); Pomme, S.; Hardenman, F. [Belgian Nuclear Research Centre, Boeretang (Belgium); Culot, J.P. [A.V. Nuclear, Brussels (Belgium)] [and others

1997-10-01

11

In situ gamma-ray spectrometry in forests: determination of kerma rate in air from 137Cs  

Microsoft Academic Search

A method is presented to determine the kerma rate in air from 137Cs due to Chernobyl fallout in forests. In situ gamma-ray spectra from several forest sites in Russia, in the Ukraine and in Southern Germany are evaluated with the aim of deducing the ratio of primary and forward scattered photons for 137Cs. With this ratio and the results of

F. Gering; P. Kiefer; S. Fesenko; G. Voigt

2002-01-01

12

ANNEX 52 Monte Carlo model of a gamma spectrometry system for in situ assessment of induced activity at fusion reactor components  

Microsoft Academic Search

In this work, a preliminary design of a gamma spectrometer system for in situ radioactivity assay of induced activity at components of a future fusion power plant is presented. The system incorporates a HPGe detector, gamma ray shielding and an adjustable collimator. Monte Carlo code MCNP was used to predict the system response for assaying a wall composed of activated

F. Tzika; I. E. Stamatelatos

13

Small Scale Assessment of Spatial and Vertical Redistribution of Fukushima Fallouts Radiocaesium in Contaminated Soil Using in-situ HPGe Gamma Ray Spectrometry  

NASA Astrophysics Data System (ADS)

After Tohoku earthquake on March 11th 2011, the subsequent tsunami and the resulting Fukushima Daiichi Nuclear Power Plant disaster, gamma emitting particles, first release into the atmosphere, were quickly deposited on the soil surface, with potentially harmful level in the surroundings of the nuclear power plant. Thus, the evaluation of soil deposition pattern, depth migration and afterward radionuclides redistribution and export by erosion and hydrological processes is fundamental for contamination assessments and to plan future actions. Our study site is located 37km from Fukushima power plant, inside the evacuated zone. In this study, we used a bounded erosion plot of 22.1m x 5m to assess global export of sediments and 137Cs. This plot, previously cropped with tobacco, is morphologically divided into inter-rill areas separated by rills that formed into former wheel tracks. The bottom of the plot is subject to deposition of sediments. In order to determine and quantify the internal processes responsible of the export of sediment, the depth distribution of 137Cs is estimated using a portable High Purity Germanium (HPGe) detector. Such a portable device, associated to the high radiation levels, allow an acquisition of spatially distributed data within the plot in a reasonable time (1 min/sample). At the same time, depth distribution of 137Cs are measured using the scrapper plate technique, adapted to obtain a fine resolution in the first, highly contaminated, centimeters of soil. Finally, 137Cs depth profiles, associated with in situ and laboratory gamma spectrums acquired with the portable detector, allow for the detector calibration. Although the initial deposit can reasonably be supposed homogeneous at the plot scale, the dataset obtained 3 months later shows high spatial and temporal variability due to erosion processes. Measurements with the portable HPGe detector proved to be useful at this small scale, avoiding the needs of a large number of soil samples, and our results are promising to understand erosion at larger scale where horizontal patterns of deposition and redistribution are usually supposed homogeneous over quite larger areas.

Patin, J.; Onda, Y.; Yoda, H.; Kato, H.

2011-12-01

14

Underground Gamma-Ray Spectrometry  

Microsoft Academic Search

Gamma-ray spectrometry using high purity Ge detectors has made significant advances in recent years because large crystals have become readily available and the importance of very radiopure materials in the construction of detectors has been understood. The combination of these improvements has made it possible to decrease detection limits in special low-background counting systems. Gamma-ray spectrometry systems located underground are

Mikael Hult; Matthias Köhler; Nova Gorica

15

An experimental comparison of in-situ gamma spectrometric methods for quantifying Cs137 radioactive contamination in the ground  

Microsoft Academic Search

In-situ gamma spectrometry is a potentially powerful method for rapid quantification of radioactive contamination in the ground using an above-ground detector. The accuracy of the technique, however, depends on having information on the activity variation with depth. Three methods have previously been proposed for deriving this information using information obtained in the field. This paper describes these methods and models

J. MacDonald; C. J. Gibson; P. J. Fish; D. J. Assinder

1999-01-01

16

Continuous gamma-ray spectrometry in the Fast Flux Test Facility (FFTF)  

NASA Astrophysics Data System (ADS)

Gamma ray continua were measured at startup in the Fast Flux Test Facility (FFTF). A special FFTF insert, called the In-Reactor Thimble (IRT), provided an adequate environment for in situ operation of the gamma spectrometer. The IRT replaced a fuel assembly near core center (No. 2101) and measurements were conducted at three axial locations, namely midplane, the lower axial shield, and the upper axial reflector. Observations were carried out with Compton Recoil Gamma Ray Spectrometry at the state of the art. Advantage was thereby taken of the most recent advances, including extension of gamma ray spectrometry up to roughly 7 MeV with the new in situ Janus detector probe.

Gold, R.; Kaiser, B. J.; Moore, F. S., Jr.; Bunch, W. L.; McElroy, W. N.; Sheen, E. M.

1980-10-01

17

Low-level gamma-ray spectrometry  

Microsoft Academic Search

Low-level gamma-ray spectrometry generally equates to high-sensitivity gamma-ray spectrometry that can be attained by background reduction, selective signal identification, or some combination of both. Various methods for selectively identifying gamma-ray events and for reducing the background in gamma ray spectrometers are given. The relative magnitude of each effect on overall sensitivity and the relative 'cost' for implementing them are given

R L Brodzinski

1991-01-01

18

Accounting for spatial variability and fields of view in environmental gamma ray spectrometry  

Microsoft Academic Search

Spatial variability is an important feature in many environmental studies, which influences comparison estimates of environmental radioactivity from soil samples and in-situ or airborne ?-ray spectrometry. Comparisons between ground based and airborne gamma ray spectrometry are needed both for interpretation and for calibration purposes. However, under normal environmental conditions such comparisons may be affected by the considerable differences in the

A. N. Tyler; D. C. W. Sanderson; E. M. Scott; J. D. Allyson

1996-01-01

19

Low-level gamma-ray spectrometry  

SciTech Connect

Low-level gamma-ray spectrometry generally equates to high-sensitivity gamma-ray spectrometry that can be attained by background reduction, selective signal identification, or some combination of both. Various methods for selectively identifying gamma-ray events and for reducing the background in gamma-ray spectrometers are given. The relative magnitude of each effect on overall sensitivity and the relative cost'' for implementing them are given so that a cost/benefit comparison can be made and a sufficiently sensitive spectrometer system can be designed for any application without going to excessive or unnecessary expense. 10 refs., 8 figs.

Brodzinski, R.L.

1990-10-01

20

In-Situ Photoacoustic Spectrometry for Corrosion Studies.  

National Technical Information Service (NTIS)

These preliminary experiments showed that detectable acoustic signals can be obtained with an illumination intensity of the electrode which does not produce a significant photoelectrochemical effect. We therefore are confident that in-situ photoacoustic s...

C. E. Vallet G. M. Brown

1983-01-01

21

In-situ high-resolution gamma-spectrometric survey of burial ground-monitoring wells  

SciTech Connect

In situ high resolution gamma-ray spectrometry with an intrinsic germanium detector assembly of special design surveyed the burial ground monitoring wells to locate and identify gamma emitters that may have migrated from the burial trenches toward the water table. Gamma-ray spectra were acquired as a function of depth in each well and recorded on magnetic tape. These spectra were reduced by a series of computer programs to produce count rate versus depth profiles for natural and man-made activities. The original spectra and the profiles have been archived on magnetic tape for comparison with similar future surveys. Large amounts of man-made activities were observed in some of the burial trenches; however, below the trench bottoms, only very low but detectable amounts of /sup 60/Co and /sup 137/Cs were observed in eleven wells. The highest level of man-made gamma activity observed below the trench bottoms has a count rate roughly equal to that observed for uranium daughter activities which are natural to the subsoil.

Bowman, W.W.

1981-09-01

22

Factors influencing in situ gamma-ray measurements  

NASA Astrophysics Data System (ADS)

Introduction In situ passive gamma-ray sensors are very well suitable for mapping physical soil properties. In order to make a qualitative sound soil map, high quality input parameters for calibration are required. This paper will focus on the factors that affect the output of in situ passive gamma-ray sensors, the primary source, soil, not taken into account. Factors The gamma-ray spectrum contains information of naturally occurring nuclides 40K, 238U and 232Th and man-made nuclides like 137Cs, as well as the total count rate. Factors that influence the concentration of these nuclides and the count rate can be classified in 3 categories. These are sensor design, environmental conditions and operational circumstances. Sensor design The main elements of an in situ gamma-ray sensor that influence the outcome and quality of the output are the crystal and the spectrum analysis method. Material and size of the crystal determine the energy resolution. Though widely used, NaI crystals are not the most efficient capturer of gamma radiation. Alternatives are BGO and CsI. BGO has a low peak resolution, which prohibits use in cases where man-made nuclides are subject of interest. The material is expensive and prone to temperature instability. CsI is robust compared to NaI and BGO. The density of CsI is higher than NaI, yielding better efficiency, especially for smaller crystal sizes. More volume results in higher energy efficiency. The reduction of the measured spectral information into concentration of radionuclides is mostly done using the Windows analysis method. In Windows, the activities of the nuclides are found by summing the intensities of the spectrum found in a certain interval surrounding a peak. A major flaw of the Windows method is the limited amount of spectral information that is incorporated into the analysis. Another weakness is the inherent use of ‘stripping factors' to account for contributions of radiation from nuclide A into the peak of nuclide B. This can be overcome using Full Spectrum Analysis (FSA). This method incorporates virtually all data present in the measured gamma spectrum. In FSA, a Chi-squared algorithm is used to fit a set of "Standard Spectra" to the measured spectrum. The uncertainty in the FSA method is at least a factor 2 lower compared to the Windows method. Environmental conditions Environmental conditions can influence the signal output and therefore the quality. In general, the density of the medium through which gamma-radiation travels determines the interaction of the radiation with matter and thus affects the sensor readings. Excluding soil as being the source; water is the most important external factor in this respect. The amount of water in soil will affect the signal. In general, energy loss occurs as water content in soil increases. As a result, the nuclide concentrations will be lower. Monte Carlo simulations show a difference of 16% in nuclide concentration for completely dry and fully saturated sandy soils. Another water related issue is rainfall. With rain radon gas, a product of 238U, will precipitate. This causes spectral noise effects. Snow and fog have the same effect to a minor degree. Another aspect is the openness of soil. From experience we know that the concentration of 40K differs if soil is tilled. Finally, on earth there is always radioactive noise present from the galaxy. The "Standard Spectra" used in the FSA method can take noise and geometric effects into account. Operational circumstances During a survey an operator should be aware of the effects of driving speed and measurement height. In general, a larger crystal has better energy efficiency and is therefore more suitable for high speed. E.g. a 70 x 150 mm CsI crystal provides qualitative satisfactory output for soil mapping up to 10 km/hr. Sample locations, however, are best measured during a longer period (3 to 5 minutes). The measurement height affects the measurement resolution; the lower the sensor, the smaller the measured area. In addition, Monte Carlo simulations show that the m

Loonstra, E. H.; van Egmond, F. M.

2009-04-01

23

Characterizing marine hydrocarbons with in-situ mass spectrometry  

Microsoft Academic Search

Identification and tracking of hydrocarbons in the marine environment is challenging. State of the art systems typically rely on surface slicks to identify hydrocarbon contamination such as oil spills. Subsurface detection remains challenging. This paper describes the TETHYS in-situ mass spectrometer and results of real-world deployments. TETHYS is a small, self contained mass spectrometer capable of operation to 5000 meters

R. Camilli; A. Duryea

2007-01-01

24

MONITORING GENETIC & METABOLIC POTENTIAL FOR IN SITU BIOREMEDIATION: MASS SPECTROMETRY  

EPA Science Inventory

A number of DOE sites are contaminated with mixtures of dense non-aqueous phase liquids (DNAPLs) such as carbon tetrachloride, chloroform, perchloroethylene, and trichloroethylene. At many of these sites, in situ microbial bioremediation is an attractive strategy for cleanup, sin...

25

Mass spectrometry imaging for in situ kinetic histochemistry  

PubMed Central

Tissues are composed of diverse cell subpopulations each with distinct metabolic characteristics that influence overall behavior. Unfortunately, traditional histopathology imaging techniques are ‘blind’ to the spatially ordered metabolic dynamics within tissue. While mass spectrometry imaging enables spatial mapping of molecular composition, resulting images are only a static snapshot in time of molecules involved in highly dynamic processes; kinetic information of flux through metabolic pathways is lacking. To address this limitation, we developed kinetic mass spectrometry imaging (kMSI), a novel technique integrating soft desorption/ionization mass spectrometry with clinically accepted in vivo metabolic labeling of tissue with deuterium to generate images of kinetic information of biological processes. Applied to a tumor, kMSI revealed heterogeneous spatial distributions of newly synthesized versus pre-existing lipids, with altered lipid synthesis patterns distinguishing region-specific intratumor subpopulations. Images also enabled identification and correlation of metabolic activity of specific lipids found in tumor regions of varying grade.

Louie, Katherine B.; Bowen, Benjamin P.; McAlhany, Stephanie; Huang, Yurong; Price, John C.; Mao, Jian-hua; Hellerstein, Marc; Northen, Trent R.

2013-01-01

26

Mass spectrometry imaging for in situ kinetic histochemistry  

NASA Astrophysics Data System (ADS)

Tissues are composed of diverse cell subpopulations each with distinct metabolic characteristics that influence overall behavior. Unfortunately, traditional histopathology imaging techniques are `blind' to the spatially ordered metabolic dynamics within tissue. While mass spectrometry imaging enables spatial mapping of molecular composition, resulting images are only a static snapshot in time of molecules involved in highly dynamic processes; kinetic information of flux through metabolic pathways is lacking. To address this limitation, we developed kinetic mass spectrometry imaging (kMSI), a novel technique integrating soft desorption/ionization mass spectrometry with clinically accepted in vivo metabolic labeling of tissue with deuterium to generate images of kinetic information of biological processes. Applied to a tumor, kMSI revealed heterogeneous spatial distributions of newly synthesized versus pre-existing lipids, with altered lipid synthesis patterns distinguishing region-specific intratumor subpopulations. Images also enabled identification and correlation of metabolic activity of specific lipids found in tumor regions of varying grade.

Louie, Katherine B.; Bowen, Benjamin P.; McAlhany, Stephanie; Huang, Yurong; Price, John C.; Mao, Jian-Hua; Hellerstein, Marc; Northen, Trent R.

2013-04-01

27

Mass spectrometry guided in situ proteolysis to obtain crystals for X-ray structure determination  

Microsoft Academic Search

A strategy for increasing the efficiency of protein crystallization\\/structure determination with mass spectrometry has been\\u000a developed. This approach combines insights from limited proteolysis\\/mass spectrometry and crystallization via in situ proteolysis.\\u000a The procedure seeks to identify protease-resistant polypeptide chain segments from purified proteins on the time-scale of\\u000a crystal formation, and subsequently crystallizing the target protein in the presence of the optimal

Tarun Gheyi; Logan Rodgers; Richard Romero; J. Michael Sauder; Stephen K. Burley

2010-01-01

28

Neutral beam species measurements using in situ Rutherford backscatter spectrometry  

SciTech Connect

This work describes a new in situ method for measuring the neutral particle fractions in high power deuterium neutral beams, used to heat magnetically confined fusion plasmas. Deuterium beams, of variable energies, pulse lengths, and powers up to 47 keV, 100 msec, 1.6 MW, were Rutherford backscattered at 135/sup 0/ from TiC inner neutral beam armor of the PDX, and detected using an electrostatic analyzer with microchannel plates. Complete energy scans were made every 20 msec and data were obtained simultaneously from five different positions across the beam profile. The neutral particle fractions were measured to be D/sup 0/(E):D/sup 0/(E/2):D/sup 0/(E/3)=53:32:15. The corresponding neutral power fractions were P/sup 0/(E):P/sup 0/(E/2):P/sup 0/(E/3)=72:21:7, and the associated ionic fractions at the output of the ion source were D/sub 1//sup +/(E):D/sub 2//sup +/(E):D/sub 3//sup +/(E)=74:20:6. The measured neutral particle fractions were relatively constant over more than 70% of the beam power distribution. A decrease in the yield of the full energy component in the outer regions of the beam was observed. Other possible experimental configurations and geometries are discussed.

Kugel, H.W.; Kaita, R.; Gammel, G.; Williams, M.D.

1984-12-01

29

Neutron capture gamma-ray technique for in situ mineral analysis.  

National Technical Information Service (NTIS)

The application of neutron capture gamma ray method for in situ analysis of mineral deposits is discussed. A borehole sonde for prompt gamma analysis (PGA) using a 3 Ci Americium-Beryllium neutron source and a hyper pure germanium detector has been design...

A. A. Elkady W. H. Abulfaraj A. F. Abdulfattah

1987-01-01

30

Planetary Geochemistry Techniques: Probing In-Situ with Neutron and Gamma Rays (PING) Instrument.  

National Technical Information Service (NTIS)

The Probing In situ with Neutrons and Gamma rays (PING) instrument is a promising planetary science application of the active neutron-gamma ray technology so successfully used in oil field well logging and mineral exploration on Earth. The objective of ou...

A. Parsons D. Burger J. Bodnarik J. Schweitzer J. Trombka L. Evans L. Lin M. Nankung R. Starr S. Floyd S. Nowicki T. McClanahan

2011-01-01

31

Monitoring genetic and metabolic potential for in situ bioremediation: Mass spectrometry. 1997 annual progress report  

SciTech Connect

'A number of US Department of Energy (DOE) sites are contaminated with mixtures of dense non-aqueous phase liquids (DNAPLs) such as carbon tetrachloride, chloroform,. perchloroethylene, and trichloroethylene. At many of these sites, in situ microbial bioremediation is an attractive strategy for cleanup because it has the potential to degrade DNAPLs in situ without producing toxic byproducts. A rapid screening method to determine the broad range metabolic and genetic potential for contaminant degradation would greatly reduce the cost and time involved in assessment for in situ bioremediation as well as for monitoring ongoing bioremediation treatment. In this project, the ORNL Organic Mass Spectrometry (OMS) group is developing mass-spectrometry-based methods to screen for the genetic and metabolic potential for assessment and monitoring of in situ bioremediation of DNAPLs. In close collaboration, Professor Mary Lidstrom''s group at the University of Washington is identifying short DNA sequences related to microbial processes involved in the biodegradation of pollutants. This work will lay the foundation for development of a field-portable mass-spectrometry-based technique for rapid assessment and monitoring of bioremediation processes on site.'

Buchanan, M.V.; Hurst, G.B.; Britt, P.F.; McLuckey, S.A.; Doktycz, M.J.

1997-09-01

32

In-situ gamma-analysis support for Phase I, Middlesex cleanup project, Middlesex, New Jersey  

SciTech Connect

At the request of the Department of Energy, the Energy Measurements Group of EG and G participated in the Remedial Action program for the former Middlesex Sampling Plant and associated properties at Middlesex, New Jersey from July to November 1980. EG and G provided real time analysis of the radiological character of the soil of each property included in the Phase I cleanup before, during, and after decontamination. The method used for the analysis was in situ gamma spectroscopy employing a high purity germanium detector. This report describes the in situ system and displays the results of the in situ measurements before and after decontamination of the properties surveyed during Phase I.

Reiman, R.T.

1983-07-01

33

Time resolved gamma-ray spectrometry  

Microsoft Academic Search

A new approach is proposed for the measurement of the time-dependent processes in gamma-ray spectrometry. During data acquisition,\\u000a the energy and the detection time of each event are recorded and the data are later analyzed off-line. This separation of\\u000a acquisition and data handling extends the possibilities of the analysis. A series of demonstration experiments was performed\\u000a to show the feasibility

L. Szentmiklósi; T. Belgya; G. L. Molnár; Zs. Révay

2007-01-01

34

Linssi : Database for gamma-ray spectrometry  

Microsoft Academic Search

Linssi is a Structured Query Language (SQL) database for HPGe gamma-ray spectrometry. It covers the whole production chain from\\u000a sample preparation to final analysis results. Static or mobile sampling and measurement and multiple sample types are supported.\\u000a In addition, each sample can be split or combined any number of times. A sample may be measured multiple times and each measurement

P. A. Aarnio; J. J. Ala-Heikkilä; A. Isolankila; A. Kuusi; M. Moring; M. Nikkinen; T. Siiskonen; H. Toivonen; K. Ungar; W. Zhang

2008-01-01

35

Comparison of in situ and laboratory gamma spectroscopy of natural radionuclides in desert soil  

SciTech Connect

In situ and laboratory gamma spectroscopy were used to characterize natural background levels of radiation in the soil at eight sites around the Yucca Mountain Range. The purpose of this practical field analysis was to determine if published empirical in situ calibration factors would yield accurate quantitative specific activities (Bq kg{sup -1}) in a desert environment. Corrections were made to the in situ calibration factors to account for the on-axis response of a detector with a thin beryllium end window. The in situ gamma spectroscopy results were compared to laboratory gamma spectroscopy of soil samples gathered from each site. Five natural radionuclides were considered: {sup 40}K, {sup 214}Pb, {sup 214}Bi, {sup 208}Tl, and {sup 228}Ac. The in situ determined specific activities were consistently within {+-}15% of the laboratory soil sample results. A quantitative discussion of the factors contributing to the uncertainty in the in situ and laboratory results is included. Analysis on the specific activity data using statistical hypothesis tests determined that three nuclides, {sup 214}Pb, {sup 214}Bi, and {sup 228}Ac showed a weak site dependence while the other two nuclides, {sup 40}K, and {sup 208}Tl, did not exhibit a site dependence. Differing radiation background levels from site to site along with in situ and laboratory uncertainties in excess of 10% are two factors that account for the weak site dependence. Despite the good correlation between data, it was recommended that the in situ detector be calibrated by a detector-specific Monte Carlo code which would accurately model more complex geometries and source distributions. 19 refs., 4 figs., 7 tabs.

Benke, R.R.; Kearfott, K.J. [Univ. of Michigan, Ann Arbor, MI (United States)

1997-08-01

36

A Hybrid X-Gamma Detector for In-situ Planetary Science  

NASA Astrophysics Data System (ADS)

A new generation of hybrid X-ray and gamma ray detectors is being developed by the University of Leicester in collaboration with Eurorad, France. This type of detector is being developed for surface and subsurface in-situ planetary science applications. Gamma rays generated from neutron-induced interactions with a planetary surface as well as emissions from radioactive elements will allow an X-Gamma detector to analyze the bulk composition of the surface and sub-surface of any planetary body, the depth of analysis being dependent on the configuration of the instrumented probe. Gamma backscatter densitometry is a non-destructive in-situ method for measuring the bulk density of surrounding material that exploits the Compton effect. The bulk density can be used to measure heat flow through a planetary body as a function of depth. X-Gamma, used in conjunction with a small gamma ray source may be used to measure the bulk density of a planetary surface as well as the bulk composition. The use of such a detector on a planetary surface could aid in our understanding of the evolution of a planetary body and enable us to complement orbital gamma ray measurements by mapping the gamma ray emissions at a higher spatial resolution. In-situ analysis could aid in detecting trace elements that have not been previously detected by orbital gamma ray spectrometers. In this study we describe the progress made on the X-Gamma project, including the characterization of several possible gamma ray detectors for the hybrid detector. The results obtained during several experimental detector test campaigns at the neutron beam facility, FRM-2 in Munich, Germany will also be reported.

Skidmore, Michelle; Ambrosi, Richard; Nelms, Nick; Ball, Andrew; Wolters, Stephen; Simon, Hervé; Bannister, Nigel

37

Direct analysis of reference biofluids by coupled in situ electrodeposition-electrothermal atomic absorption spectrometry  

NASA Astrophysics Data System (ADS)

The application of coupled in situ electrodeposition-electrothermal atomic absorption spectrometry (ED-ETAAS) to the determination of Pb in biological standard reference materials is described. In situ electrodeposition at a cell voltage of 3.0 V from 25-?l samples onto electrodeposited Pd is used to quantitatively separate the analyte from blood and urine matrices. With subsequent withdrawal of spent electrolyte, this overcomes the atomisation problems inherent with high salt and organic contents. ED-ETAAS is applied with minimal sample pre-treatment (acidification). The electrolysis process aids decomposition of the organic matrix, and the release of trace elements. Evolution of H 2 at the cathode counters fouling of the Pd modifier surface. The palladium deposit is renewed in situ for each determination. For AMI certified lyophilised blood, diluted 1+3 with 0.1 M HCl (18.1 ?g/l Pb), the R.S.D. was 3.0% (peak height; n=5) and the detection limit (3 ? blank; n=5) was 1.5 ?g/l. Results for certified blood samples were AMI 72.3±4.3 ?g/l (certified 76.2±7.6 ?g/l) and Seronorm 34.2±2.0 ?g/l (36±4 ?g/l). The result for NIST SRM 2670 normal urine acidified to 1% HNO 3 was 8.1±0.6 ?g/l (recommended value 10 ?g/l).

Matousek, Jaroslav P.; Powell, Kipton J.

1999-12-01

38

In situ gamma spectroscopy for the Yucca Mountain site characterization project  

SciTech Connect

In situ and laboratory gamma spectroscopy were used to characterize natural background levels of radiation in the soil at 8 sites around the Yucca Mountain Range. The purpose of the field analysis was to determine if the published in situ calibration factors would yield accurate quantitative specific activities (Bq kg{sup -1}) in a desert environment. Corrections were made to the in situ calibration factors to account for a thin Be end window. The in situ gamma spectroscopy results were compared to laboratory gamma spectroscopy of soil samples gathered from each site. Five natural radionuclides were considered: {sup 40}K, {sup 214}Pb, {sup 214}Bi, {sup 208}Tl, and {sup 228}Ac. The in situ determined specific activities for the nuclides except {sup 208}Tl were constantly within {+-}15% of the laboratory soil sample results. The end window corrected in situ determinations for {sup 208}Tl were on average 34.7% higher than the laboratory results. It was discovered that drying the soil samples at 120{degrees}C accelerated the loss of {sup 222}Rn. In the time between soil sample drying and laboratory gamma counting, the specific activities of {sup 214}Pb and {sup 214}Bi exhibited buildups characteristic of the hall-life of {sup 222}Rn. Fitting analytical Solutions to the buildup curves of {sup 214}Pb and {sup 214}Bi, the {sup 222}Rn exhalation removal constant from undisturbed desert soil was determined to be 0.021 d{sup -1}, and the accelerated {sup 222}Rn removal constant for drying at 120{degrees}C was determined to be 0.081 d{sup -1}. To avoid the effects of {sup 222}Rn loss and buildup in dried soil samples, the soil samples should be sealed and stored for at least 15 d to allow for 99% buildup of {sup 222}Rn and its progeny. Despite the good correlation between data, it was recommended that the in situ detector be calibrated by a detector specific Monte Carlo code which would accurately model more complex geometries and source distributions.

Benke, R.R.; Kearfott, K.J. [Univ. of Michigan, Ann Arbor, MI (United States); Schoep, D.; Tung, C. [Science Applications International Corp., Las Vegas, NV (United States)

1996-06-01

39

Advanced Mass Spectrometry for In Situ Analysis of Comet and Primitive Asteroid Composition  

NASA Astrophysics Data System (ADS)

The study of the composition of comets and icy, carbonaceous asteroids has benefitted greatly by sustained efforts in recent years to observe and conduct spectroscopy on these objects from terrestrial and orbital observatories. Our ability to classify these small bodies and conduct comparisons between individual objects has broadened our understanding of the commonalities and diversity that they exhibit. To contribute to and complement our understanding of the formation, distribution, and evolution of small bodies throughout the solar system, it will be critical to form connections between broad surveys of coma composition and in situ measurements of evolved compounds at various distances from the nuclei of representative objects. Future missions that can inform our understanding of coma-nucleus interactions could take the form of a close flyby, an orbiter, or a lander, or some combination. We present recent efforts by our group to develop compact but capable analytical instrumentation that spans the scope of mission opportunities, offering advanced mass spectrometric analysis of the composition of near-surface volatiles and the parent species at the surface. It is now feasible, with mature instrumentation and recent advances in mass spectrometry and sampling, to address the connection between surface materials and the evolution of gases and small organic species, thereby establishing the relationship between in situ measurements of parent compounds and remote observations of product species in the coma. Three instrument development efforts will be presented, spanning the opportunities for sampling the in situ composition of a comet or active asteroid: (1) highly sensitive and mature mass analyzers to sample volatile production near the surface of the body, (2) a gas and dust collector that is optimized for the analysis of trace volatiles, such as astrochemically important small organics, and dust that may be lofted by surface activity, and (3) laser desorption/ionization mass spectrometry that is well suited to landed analyses of non-volatile inorganic and organic composition of nucleus surface materials.

Getty, Stephanie; Mahaffy, P. R.; Brinckerhoff, W. B.; Benna, M.; Arevalo, R. D.; Cornish, T.; Elsila, J.

2013-10-01

40

Matrix-assisted laser desorption ionization imaging mass spectrometry: in situ molecular mapping.  

PubMed

Matrix-assisted laser desorption ionization imaging mass spectrometry (IMS) is a relatively new imaging modality that allows mapping of a wide range of biomolecules within a thin tissue section. The technology uses a laser beam to directly desorb and ionize molecules from discrete locations on the tissue that are subsequently recorded in a mass spectrometer. IMS is distinguished by the ability to directly measure molecules in situ ranging from small metabolites to proteins, reporting hundreds to thousands of expression patterns from a single imaging experiment. This article reviews recent advances in IMS technology, applications, and experimental strategies that allow it to significantly aid in the discovery and understanding of molecular processes in biological and clinical samples. PMID:23259809

Angel, Peggi M; Caprioli, Richard M

2013-01-16

41

In situ metabolic profiling of single cells by laser ablation electrospray ionization mass spectrometry.  

PubMed

Depending on age, phase in the cell cycle, nutrition, and environmental factors, individual cells exhibit large metabolic diversity. To explore metabolic variations in cell populations, laser ablation electrospray ionization (LAESI) mass spectrometry (MS) was used for the in situ analysis of individual cells at atmospheric pressure. Single cell ablation was achieved by delivering mid-IR laser pulses through the etched tip of a GeO(2)-based glass fiber. Metabolic analysis was performed from single cells and small cell populations of Allium cepa and Narcissus pseudonarcissus bulb epidermis, as well as single eggs of Lytechinus pictus. Of the 332 peaks detected for A. cepa, 35 were assigned to metabolites with the help of accurate ion masses and tandem MS. The metabolic profiles from single cells of the two plant species included a large variety of oligosaccharides including possibly fructans in A. cepa, and alkaloids, e.g., lycorine in N. pseudonarcissus. Analysis of adjacent individual cells with a difference in pigmentation showed that, in addition to essential metabolites found in both variants, the pigmented cells contained anthocyanidins, other flavonoids, and their glucosides. Analysis of single epidermal cells from different scale leaves in an A. cepa bulb showed metabolic differences corresponding to their age. Our results indicate the feasibility of using LAESI-MS for the in situ analysis of metabolites in single cells with potential applications in studying cell differentiation, changes due to disease states, and response to xenobiotics. PMID:19824712

Shrestha, Bindesh; Vertes, Akos

2009-10-15

42

In situ silylation for the multicomponent analysis of canola oil by-products by gas chromatography–mass spectrometry  

Microsoft Academic Search

In this study, a simple method for the determination of free fatty acids, phytosterols, tocopherols, mono and diglycerides present in canola oil deodorizer distillate (DD) and soapstock samples was developed. Analytes were derivatized “in situ” using a mixture of hexamethyldisilazane (HMDS), pyridine and trifluoroacetic acid; separated by gas chromatography (GC) with mass spectrometry (MS) for final detection. Two drying procedures

Armando A. Durant; Marie-Josée Dumont; Suresh S. Narine

2006-01-01

43

In situ capture gamma-ray analysis of coal in an oversize borehole  

USGS Publications Warehouse

In situ capture gamma-ray analysis in a coal seam using a high resolution gamma-ray spectrometer in a close-fitting borehole has been reported previously. In order to check the accuracy of the method under adverse conditions, similar measurements were made by means of a small-diameter sonde in an oversize borehole in the Pittsburgh seam, Greene County, Pennsylvania. The hole was 5 times the diameter of the sonde, a ratio that substantially increased the contribution of water (hydrogen) to the total spectral count and reduced the size of the sample measured by the detector. The total natural count, the 40K,count, and the intensities of capture gamma rays from Si, Ca, H, and Al were determined as a function of depth above, through, and below the coal seam. From these logs, the depth and width of the coal seam and its partings were determined. Spectra were accumulated in the seam for 1 h periods by using neutron sources of different strengths. From the spectra obtained by means of several 252Cf neutron sources of different sizes, the ultimate elemental analysis and ash content were determined. The results were not as good as those obtained previously in a close-fitting borehole. However, the results did improve with successively larger source-to-detector distances, i.e.,as the count contribution due to hydrogen in the water decreased. It was concluded that in situ borehole analyses should be made in relatively close-fitting boreholes. ?? 1983.

Mikesell, J. L.; Dotson, D. W.; Senftle, F. E.; Zych, R. S.; Koger, J.; Goldman, L.

1983-01-01

44

In-situ gamma-PHA measurements to support unconditional release of 235-F chiller units  

SciTech Connect

The Analytical Development Section of Savannah River Technology Center (SRTC) was requested by the Facility Decommission Division (FDD) to conduct in-situ gamma-ray pulse height analysis measurements to support the unconditional release of 235-F chiller units. The chiller units were used to cool process water in the 235-F facility. The measurements' main goal is to confirm that there is no process-related contaminants present on the chillers. For each of the two F-area clean water chillers, the authors have acquired ten gamma-ray pulse height analysis spectra. This report will discuss the purpose of the measurements, the experimental setup, data acquisition, calculations and results, and a conclusion of the study.

Salaymeh, S.R.

2000-02-17

45

Time-resolved neutron/gamma-ray data acquisition for in situ subsurface planetary geochemistry  

NASA Astrophysics Data System (ADS)

The current gamma-ray/neutron instrumentation development effort at NASA Goddard Space Flight Center aims to extend the use of active pulsed neutron interrogation techniques to probe the subsurface elemental composition of planetary bodies in situ. Previous NASA planetary science missions, that used neutron and/or gamma-ray spectroscopy instruments, have relied on neutrons produced from galactic cosmic rays. One of the distinguishing features of this effort is the inclusion of a high intensity 14.1 MeV pulsed neutron generator synchronized with a custom data acquisition system to time each event relative to the pulse. With usually only one opportunity to collect data, it is difficult to set a priori time-gating windows to obtain the best possible results. Acquiring time-tagged, event-by-event data from nuclear induced reactions provides raw data sets containing channel/energy, and event time for each gamma ray or neutron detected. The resulting data set can be plotted as a function of time or energy using optimized analysis windows after the data are acquired. Time windows can now be chosen to produce energy spectra that yield the most statistically significant and accurate elemental composition results that can be derived from the complete data set. The advantages of post-processing gamma-ray time-tagged event-by-event data in experimental tests using our prototype instrument will be demonstrated.

Bodnarik, J. G.; Burger, D. M.; Burger, A.; Evans, L. G.; Parsons, A. M.; Schweitzer, J. S.; Starr, R. D.; Stassun, K. G.

2013-04-01

46

Scintillation gamma Spectrometry with a Stilbene Crystal.  

National Technical Information Service (NTIS)

A method of converting apparatus for amplitude dispersion to energy dispersion of gamma quanta measured with a single stilbene crystal gamma spectrometer is described. One of the main advantages of this spectrometer is the possibility of practically simul...

Y. I. Kolevatov V. I. Kukhtevich I. V. Goryachev

1969-01-01

47

MALDI Imaging Mass Spectrometry for In Situ Proteomic Analysis of Preneoplastic Lesions in Pancreatic Cancer  

PubMed Central

The identification of new biomarkers for preneoplastic pancreatic lesions (PanINs, IPMNs) and early pancreatic ductal adenocarcinoma (PDAC) is crucial due to the diseasés high mortality rate upon late detection. To address this task we used the novel technique of matrix-assisted laser desorption/ionization (MALDI) imaging mass spectrometry (IMS) on genetically engineered mouse models (GEM) of pancreatic cancer. Various GEM were analyzed with MALDI IMS to investigate the peptide/protein-expression pattern of precursor lesions in comparison to normal pancreas and PDAC with cellular resolution. Statistical analysis revealed several discriminative m/z-species between normal and diseased tissue. Intraepithelial neoplasia (PanIN) and intraductal papillary mucinous neoplasm (IPMN) could be distinguished from normal pancreatic tissue and PDAC by 26 significant m/z-species. Among these m/z-species, we identified Albumin and Thymosin-beta 4 by liquid chromatography and tandem mass spectrometry (LC-MS/MS), which were further validated by immunohistochemistry, western blot, quantitative RT-PCR and ELISA in both murine and human tissue. Thymosin-beta 4 was found significantly increased in sera of mice with PanIN lesions. Upregulated PanIN expression of Albumin was accompanied by increased expression of liver-restricted genes suggesting a hepatic transdifferentiation program of preneoplastic cells. In conclusion we show that GEM of endogenous PDAC are a suitable model system for MALDI-IMS and subsequent LC-MS/MS analysis, allowing in situ analysis of small precursor lesions and identification of differentially expressed peptides and proteins.

Gruner, Barbara M.; Hahne, Hannes; Mazur, Pawel K.; Trajkovic-Arsic, Marija; Maier, Stefan; Esposito, Irene; Kalideris, Evdokia; Michalski, Christoph W.; Kleeff, Jorg; Rauser, Sandra; Schmid, Roland M.; Kuster, Bernhard; Walch, Axel; Siveke, Jens T.

2012-01-01

48

Use of Stilbene Scintillator for gamma Spectrometry.  

National Technical Information Service (NTIS)

This report deals with the set-up and calibration of a scintillation gamma spectrometer with a single stilbene crystal, for measuring gamma spectra in the energy range from 0.5-10-MeV. The spectrometer discriminates between the measured gamma rays and the...

A. S. Makarious R. Megahid R. M. A. Maayouf

1978-01-01

49

Membrane-extraction ion mobility spectrometry for in situ detection of chlorinated hydrocarbons in water.  

PubMed

Membrane-extraction ion mobility spectrometry (ME-IMS) has been developed for in situ sampling and analysis of trace chlorinated hydrocarbons in water in a single procedure. The sampling is configured so that aqueous contaminants permeate through a spiral hollow poly(dimethylsiloxane) (PDMS) membrane and are carried away by a vapor flow through the membrane tube. The extracted analyte flows into an atmospheric-pressure chemical-ionization (APCI) chamber and is analyzed in a specially made IMS analyzer. The PDMS membrane was found to effectively extract chlorinated hydrocarbon solvents from the liquid phase to vapor. The specialized IMS analyzer has measured resolutions of R = 33 and 41, respectively, for negative- and positive-modes and is capable of detecting aqueous tetrachloroethylene (PCE) and trichloroethylene (TCE) as low as 80 and 74 microg/L in the negative ion mode, respectively. The time-dependent characteristics of sampling and detection of TCE are both experimentally and theoretically studied for various concentrations, membrane lengths, and flow rates. These characteristics demonstrate that membrane-extraction IMS is feasible for the continuous monitoring of chlorinated hydrocarbons in water. PMID:20334385

Du, Yongzhai; Zhang, Wei; Whitten, William; Li, Haiyang; Watson, David B; Xu, Jun

2010-05-15

50

Influence of spacecraft outgassing on the exploration of tenuous atmospheres with in situ mass spectrometry  

NASA Astrophysics Data System (ADS)

In situ mass spectrometry has been a powerful tool in many space missions to investigate atmospheres and exospheres of different bodies in the solar system. Applying new technologies, the mass spectrometers have become increasingly more sensitive. In this study, we show that spacecraft outgassing, which can never be completely prevented, will be the limiting factor in future missions that investigate very tenuous atmospheres and exospheres of moons, asteroids, or comets at large heliocentric distances. The Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) instrument on the European Space Agency Rosetta mission has monitored spacecraft outgassing for 6 years during the cruise phase with unprecedented instrument sensitivity. It is shown that diffusion of gas from materials and from the spacecraft interior plays an important role in maintaining a relatively permanent thin gas cloud around the spacecraft for many years. The density and composition of this gas cloud depends on location on the spacecraft, maneuvers, and payload activity. The main contaminants are water, which is adsorbed on cold surfaces, and organics from the spacecraft structure, electronics, and insulations. Decomposed lubricant material can give a significant contribution to the total background. Fortunately for Rosetta, outgassing of the spacecraft will play a minor role when the comet is close to perihelion; only in the early phase of the mission the outgassing may be larger than the cometary signature.

SchläPpi, B.; Altwegg, K.; Balsiger, H.; HäSsig, M.; JäCkel, A.; Wurz, P.; Fiethe, B.; Rubin, M.; Fuselier, S. A.; Berthelier, J. J.; de Keyser, J.; RèMe, H.; Mall, U.

2010-12-01

51

In-Situ Monitoring of Toxic Heavy Metals from RDF Combustion by Two-Dimensional Atomic Absorption Spectrometry  

Microsoft Academic Search

The method to visualize two-dimensional (2D) distributions of heavy metals in refuse-derived fuel (RDF) combustion flame by using 2D atomic absorption spectrometry (2D-AAS) was studied. In-situ monitoring of the heavy metal vaporization was performed to gather useful information on the reduction of their emissions. The RDF sample was burned on a burner with an O2\\/N2 gas mixture being supplied from

Akinori Yamamoto; Yuri Kunie; Kenji Kodama; Nelfa Desmira; Kuniyuki Kitagawa

2011-01-01

52

The application of laser ablation-inductively coupled plasma-mass spectrometry to in situ U–Pb zircon geochronology  

Microsoft Academic Search

This paper reports new developments in in situ U–Pb zircon geochronology using 266 and 213 nm laser ablation-inductively coupled plasma-mass spectrometry (LA-ICP-MS).Standard spot ablation (spot diameters 40–80 ?m) was employed, with no sampling strategies employed specifically to minimise elemental fractionation. Instead, He ablation gas and carefully replicated ablation conditions were employed to maintain constant ablation-related elemental fractionation of Pb and

Simon E. Jackson; Norman J. Pearson; William L. Griffin; Elena A. Belousova

2004-01-01

53

Monitoring genetic and metabolic potential for in situ bioremediation: Mass spectrometry. 1998 annual progress report  

SciTech Connect

'A number of DOE sites are contaminated with dense non-aqueous phase liquids (DNAPLs) such as carbon tetrachloride and trichloroethylene. At many of these sites, microbial bioremediation is an attractive strategy for cleanup, since it has the potential to degrade DNAPLs in-situ. A rapid screening method to determine the broad range potential of a site''s microbial population for contaminant degradation would greatly facilitate assessment for in-situ bioremediation, as well as for monitoring ongoing bioremediation treatment. Current laboratory-based treatability methods are cumbersome and expensive. In this project, the authors are developing methods based on matrix-assisted laser desorption/ ionization mass-spectrometry (MALDI-MS) to rapidly and accurately detect polymerase chain reaction (PCR) products. In parallel, PCR primers to amplify DNA sequences from microbial genes involved in biodegradation of pollutants are being identified that are short enough to allow MALDI-MS detection. This work will lay the foundation for development of a field-portable MS-based technique for rapid assessment and monitoring of bioremediation processes on site. This report summarizes work after 1-1/2 years of a 3-year project. In this time, the authors have demonstrated MALDI-MS-based detection of signature bacterial PCR products (Hurst et al., 1998). A model system for interfacing MALDI-MS with PCR amplification is based on the pmoA gene for the active site subunit of particulate methane monooxygenase, a bacterial enzyme that can oxidize trichloroethylene. PCR primer pairs were designed to amplify relatively short segments (99 bases and 56 bases) of this gene in Type 1 and Type 2 methanotrophs. A rapid reverse-phase purification of the resulting PCR products allows MALDI-MS detection from a fraction of one 25-microliter PCR reaction. At this level of sensitivity, MALDI-MS has considerable potential to compete with existing electrophoresis and hybridization methods for detecting PCR products in this size range. To allow increased throughput, the PerSeptive Biosystems MALDI-TOF mass spectrometer allows automated MALDI data acquisition, and they have adapted their purification scheme to a 96-well microtiter plate format that allows parallel treatment of 96 PCR reactions in about ten minutes (Weaver et al., 1998). An in-house-constructed TOF mass spectrometer is being modified to allow more fundamental studies aimed at improving the MS detection of PCR products.'

Buchanan, M.V.; Hurst, G.B.; Doktycz, M.J.; Britt, P.F.; Weaver, K. [Oak Ridge National Lab., TN (US); Lidstrom, M.; Costello, A. [Univ. of Washington, Seattle, WA (US)

1998-01-01

54

Gamma spectrometry of the minor bodies of the solar system  

SciTech Connect

The authors investigate the possibility of determining the elemental composition of the surfaces of minor bodies of the solar system (asteroids, the Martian satellites Phobos and Deimos, etc.) using spacecraft-based ..gamma..-spectrometry. The dependence of ..gamma..-photon flux on altitude above the body was calculated for body radii from 13 to 500 km. Estimates were made of the sensitivity of the determination of basic rock-forming elements with respect to changes in geometry of a factor of two, using ..gamma..-spectrometry with a 100 mm by 100 mm crystal of NaI(Tl). Finally, the time required to determine the stipulated characteristic ..gamma..-radiation of surface rocks with the given precision was derived as a function of altitude.

Surkov, Yu.A.; Moskaleva, L.P.; Manvelyan, O.S.

1987-01-01

55

CdWO4 crystal in gamma-ray spectrometry  

Microsoft Academic Search

The properties of CdWO4 (CWO) crystals in gamma spectrometry were studied. Several small samples of 10×10×3 mm size, typically used in CT X-ray detectors, were tested and then compared to the performance of a larger crystal of 20 mm in diameter and 20 mm in height. The light output, energy resolution, and non-proportionality of the CWO response versus gamma-ray energy,

M. Moszynski; M. Balcerzyk; M. Kapusta; A. Syntfeld; D. Wolski; G. Pausch; J. Stein; P. Schotanus

2004-01-01

56

Low-level gamma-ray spectrometry for environmental samples  

Microsoft Academic Search

Low-level gamma-ray spectrometry with large volume HPGe detectors has been widely used in analysis of environmental radionuclides.\\u000a The reasons are excellent energy resolution and high efficiency that permits selective and non-destructive analyses of several\\u000a radionuclides in composite samples. Although the most effective way of increasing the sensitivity of a gamma-ray spectrometer\\u000a is to increase counting efficiency and the amount of

P. P. Povinec

2008-01-01

57

Use of airborne gamma-ray spectrometry for kaolin exploration  

Microsoft Academic Search

Airborne gamma-ray spectrometry was used to define targets with kaolin potential in the Armorican Massif of Brittany, France. This exploration method is based on the principle that kaolinite, an aluminosilicate clay mineral constituting kaolin, is formed by the hydrolysis of potash feldspar with the elimination of potassium. Therefore, potassium contrast between favourable host-rock such as a leucogranite and kaolin occurrence

B. Tourliere; J. Perrin; P Le Berre; J. F Pasquet

2003-01-01

58

Further development of IDGS: Isotope dilution gamma-ray spectrometry  

SciTech Connect

The isotope dilution gamma-ray spectrometry (IDGS) technique for determining the plutonium concentration and isotopic composition of highly radioactive spent-fuel dissolver solutions has been further developed. Both the sample preparation and the analysis have been improved. The plutonium isotopic analysis is based on high-resolution, low-energy gamma-ray spectrometry. The plutonium concentration in the dissolver solutions then is calculated from the measured isotopic differences among the spike, the dissolver solution, and the spiked dissolver solution. Plutonium concentrations and isotopic compositions of dissolver solutions analyzed from this study agree well with those obtained by traditional isotope dilution mass spectrometry (IDMS) and are consistent with the first IDGS experimental result. With the current detector efficiency, sample size, and a 100-min count time, the estimated precision is {approximately}0.5% for {sup 239}Pu and {sup 240}Pu isotopic analyses and {approximately}1% for the plutonium concentration analysis. 5 refs., 2 figs., 7 tabs.

Li, T.K.; Parker, J.L. (Los Alamos National Lab., NM (United States)); Kuno, Y.; Sato, S.; Kamata, M.; Akiyama, T. (Power Reactor and Nuclear Fuel Development Corp., Tokai, Ibaraki (Japan))

1991-01-01

59

In situ determination of radon concentration and total gamma radiation in Kastel Gomilica, Croatia  

NASA Astrophysics Data System (ADS)

To determine current radiation background of the environment at the “Giricic” location in Kastel Gomilica, Croatia, in situ measurement of radon concentration (222Rn and 220Rn) in an open atmosphere on a ground level and at the height of 1.5 m has been made as well as total gamma radiation at the height of 1 m in an energy range of 15 keV to 2 MeV. The researched location was divided in three specific parts: (i) regulated area with the bottom ash and flying ash in the basis (“old” depot), (ii) unregulated area with waste materials, including bottom ash and flying ash, in the basis (“new” depot), (iii) uncontaminated area with no waste materials deposited on. Average radon concentration on a ground level was 213 Bq/m3 for the “old” depot, 214 Bq/m3 for the “new” depot and 59 Bq/m3 for the uncontaminated area and at the height of 1.5 m 20 Bq/m3 for the “old” depot, 34 Bq/m3 for the “new” depot and 26 Bq/m3 for the uncontaminated area. Average total gamma radiation values in selected energy range were 109.92 cps (counts per second) for the “old” depot, 357.76 cps for the “new” depot and 65.97 cps for the uncontaminated area. For selected radionuclides (214Pb, 137Cs, 228Ac, 234mPa, 40K and 214Bi) average gamma radiation values at characteristic energies have been determined as well.

Lovrencic, Ivanka; Barisic, Delko; Orescanin, Visnja; Lulic, Stipe

2007-10-01

60

In situ calibration of a high-resolution gamma-ray borehole sonde for assaying uranium-bearing sandstone deposits  

USGS Publications Warehouse

A method is presented for assaying radioactive sandstone deposits in situ by using a high-resolution borehole gamma-ray spectrometer. Gamma-ray photopeaks from the same spectrum acquired to analyze a sample are used to characterize gamma-ray attenuation properties, from which a calibration function is determined. Assay results are independent of differences between properties of field samples and those of laboratory or test-hole standards generally used to calibrate a borehole sonde. This assaying technique is also independent of the state of radioactive disequilibrium that usually exists in nature among members of the natural-decay chains. ?? 1985.

Day, Jr. , J. H.

1985-01-01

61

Detection of Soil Microogarnisms in Situ by Combined Gas Chromatography Mass Spectrometry.  

National Technical Information Service (NTIS)

Experimental tests were made to determine whether analysis of volatile metabolic products, formed in situ, is a viable procedure for an extraterrestrial life detection system. Laboratory experiments, carried out under anaerobic conditions with addition of...

M. Alexander J. M. Duxbury A. J. Francis J. Adamson

1972-01-01

62

Low-level single and coincidence gamma-ray spectrometry  

Microsoft Academic Search

Analyses of anthropogenic and natural gamma-ray emitters in the environment require high sensitive detector systems operating\\u000a in coincidence-anticoincidence modes. Thanks to an excellent energy resolution and a high efficiency, large volume HPGe detectors\\u000a have been widely used in low-level gamma-ray spectrometry. In the present paper we discuss the characteristics of single and\\u000a coincidence (HPGe-NaI(Tl)) arrangements suitable for analysis of environmental

I. Sýkora; M. Ješkovský; R. Janik; K. Holý; M. Chudý; P. P. Povinec

2008-01-01

63

Seabed gamma-ray spectrometry: applications at IAEA-MEL.  

PubMed

The technique of underwater gamma-ray spectrometry has been developed to complement or replace the traditional sampling-sample analysis approach for applications with space-time constraints, e.g. large areas of investigation, emergency response or long-term monitoring. IAEA-MEL has used both high-efficiency NaI(Tl) and high-resolution HPGe spectrometry to investigate contamination with anthropogenic radionuclides in a variety of marine environments. Surveys at the South Pacific nuclear test sites of Mururoa and Fangataufa have been used to guide sampling in areas of high contamination around ground zero points. In the Irish Sea offshore from the Sellafield nuclear reprocessing plant, a gamma-ray survey of seabed sediment was carried out to obtain estimates of the distribution and subsequently, for the inventory of 137Cs in the investigated area. PMID:11379061

Osvath, I; Povinec, P P

2001-01-01

64

Cascade summing effects in close geometry gamma-ray spectrometry  

Microsoft Academic Search

Low-level gamma-ray spectrometry, particularly in underground laboratories, is used to measure radioactivity in diverse close geometries, often placing samples directly on the detector which favours strong cascade summing effects. Monte-Carlo modelling of the efficiency is extended to cascade summing effects from complete decay sequences including positron emitting radionuclides. The effect of geometrical uncertainties on the overall uncertainty is presented. The

Peter N. Johnston; Mikael Hult; Joël Gasparro

2006-01-01

65

Carborne gamma-ray spectrometry. Calibration and applications  

Microsoft Academic Search

Calibration of carborne gamma-ray spectrometry systems for 137Cs is carried out with a source successively placed at 791 positions within an area of 34m×62m. A computer model supplements the measurements. Hereby a sensitivity map for a surface contamination is generated as well as line and area sensitivities. Another model converts surface sensitivity to sensitivity for a deep contamination. Use of

H. K. Aage; U. Korsbech; K. Bargholz; J. Hovgaard

2006-01-01

66

GESPECOR: A versatile tool in gamma-ray spectrometry  

Microsoft Academic Search

GESPECOR is a Monte Carlo based software developed for the computation of efficiency, of matrix effects and of coincidence summing effects in gamma-ray spectrometry. GESPECOR can be applied to coaxial and well-type HPGe or to Ge(Li) detectors and to various types of sources, including point, cylindrical, and spherical sources or Marinelli beakers. In this paper the structure of GESPECOR is

O. Sima; D. Arnold; C. Dovlete

2001-01-01

67

Radon gamma-ray spectrometry with YAP:Ce scintillator  

Microsoft Academic Search

The detection properties of a YAP:Ce scintillator (YAlO3:Ce crystal) optically coupled to a Hamamatsu H5784 photomultiplier with standard bialkali photocathode have been analyzed. In particular, the application to radon and radon-daughters gamma-ray spectrometry was investigated. The crystal response has been studied under severe extreme conditions to simulate environments of geophysical interest, particularly those found in geothermal and volcanic areas. Tests

Wolfango Plastino; Pierino De Felice; Francesco de Notaristefani

2002-01-01

68

Detection of methamphetamine in the presence of nicotine using in situ chemical derivatization and ion mobility spectrometry.  

PubMed

The detection of methamphetamine in the presence of nicotine has been successfully accomplished using in situ chemical derivatization with propyl chloroformate as the derivatization reagent and ion mobility spectrometry (IMS). The rapid detection of methamphetamine is important for forensic scientists in order to establish a chain of evidence and link criminals to the crime scene. Nicotine is pervasive in clandestine drug laboratories from cigarette smoke residue. It has been demonstrated that nicotine obscures the methamphetamine peaks in ion mobility spectrometers due to their similar charge affinities and ion mobilities, which makes their detection a challenging task. As a consequence, false positive or negative responses may arise. In situ chemical derivatization poses as a sensitive, accurate, and reproducible alternative to remove the nicotine background when detecting nanogram amounts of methamphetamine. The derivatization agent was coated onto the sample disk, and the derivatization product corresponding to propyl methamphetamine carbamate was detected. In the present study, in situ chemical derivatization was demonstrated to be a feasible method to detect methamphetamine hydrochloride as the carbamate derivative, which was baseline-resolved from the nicotine peak. Alternating least squares (ALS) was used to model the datasets. A mixture containing both compounds revealed reduced mobilities of 1.61 cm(2)/V.s and 1.54 cm(2)/V.s for methamphetamine and nicotine, respectively. The reduced mobility of propyl methamphetamine carbamate was found at 1.35 cm(2)/V.s. PMID:14961729

Ochoa, Mariela L; Harrington, Peter B

2004-02-15

69

REAL-TIME IN-SITU MEASUREMENT OF MATERIAL ELASTIC PROPERTIES IN A HIGH GAMMA IRRADIATION ENVIRONMENT  

SciTech Connect

The first measurements of elastic vibrations of an object in-situ to a high gamma irradiation field using a laser coupled resonant ultrasound method are described. A vibration mode of an Inconel hollow capped cylinder was measured throughout a period of 170 hours as the gamma radiation field was increased to 104 Gray/hour. The vibration mode frequency was observed to change in a manner consistent with the temperature dependence of the elastic stiffness coefficients of the material. These results illustrate the efficacy of the laser approach for real-time resonant ultrasound measurements in this severely hostile nuclear environment.

Ken Telschow; Rob Schley; Dave Cottle

2006-05-01

70

PLC gamma contributes to metastasis of in situ-occurring mammary and prostate tumors.  

PubMed

Phospholipase C-gamma (PLCgamma) has been implicated in tumor cell motility required for invasiveness and metastasis. Diminished tumor dissemination has been demonstrated in xenograft models, but studies in naturally-occurring tumors are lacking, having been limited by the timing of the interventions. Therefore, we generated mice that express a doxycycline (DOX)-inducible dominant-negative fragment of PLCgamma, PLCz; this approach avoids the in utero lethality caused by the absence of PLCgamma. As we targeted two de novo-occurring carcinomas of the mammary (MMTV-driven polyoma middle T antigen model, PyVmT) and prostate (TRAMP model) glands, we limited expression to these epithelial cells by driving DOX transactivator from the prostatein C3 promoter. This avoids the confounding variable of potentially abrogating motility in stromal and endothelial cells. These mice developed normally in the presence of DOX, except for limited mammary development if treated before 6 weeks and immaturity of the prostate gland if treated before 2 weeks of age. DOX-mediated induction of PLCz from age 8 to 16 weeks in PyVmT mice decreased the number of lung metastases by >10-fold (P<0.06) without a detectable effect on in situ tumor cell proliferation or tumor size. Lung metastases were also significantly decreased in the TRAMP model in which the mice expressed the PLCz fragment (P<0.05). DOX treatment itself had no effect on tumor size or metastasis in control mice, nor did it affect tumor dissemination in nontransgenic littermates. In conclusion, abrogation of the PLCgamma signaling pathway can limit the metastatic potential of carcinomas. PMID:17130835

Shepard, C R; Kassis, J; Whaley, D L; Kim, H G; Wells, A

2006-11-20

71

Imaging Mass Spectrometry for Visualization of Drug and Endogenous Metabolite Distribution: Toward In Situ Pharmacometabolomes  

Microsoft Academic Search

It is important to determine how a candidate drug is distributed and metabolized within the body in early phase of drug discovery.\\u000a Recently, matrix-assisted laser desorption\\/ionization (MALDI) imaging mass spectrometry (IMS; also referred to as mass spectrometry\\u000a imaging) has attracted great interest for monitoring drug delivery and metabolism. Since this emerging technique enables simultaneous\\u000a imaging of many types of metabolite

Yuki Sugiura; Mitsutoshi Setou

2010-01-01

72

Monitoring of submarine groundwater discharge along the Donnalucata coast in the south-eastern Sicily using underwater gamma-ray spectrometry  

Microsoft Academic Search

A novel technique for monitoring of submarine groundwater discharge (SGD) in coastal zones based on an in situ underwater gamma-ray spectrometry of radon-decay products is described. Several sites were visited during the IAEA’2002 expedition offshore Donnalucata in the south-eastern Sicily. Continuous monitoring of 222Rn in the beach spring at Donnalucata has shown variable 222Rn activity concentrations in groundwater (from 12

Pavel P. Povinec; Jean-Francois Comanducci; Isabelle Levy-Palomo; Benjamino Oregioni

2006-01-01

73

In situ hafnium isotope ratio analysis of zircon by inductively coupled plasma multiple collector mass spectrometry  

Microsoft Academic Search

Hf isotopic data are reported for ten ?0.01-mm2 subareas of a zircon crystal separated from the ? 318-Ma diatreme of Elie Ness, Fife, Scotland. In situ analysis was achieved by ablation sampling with a Nd:YAG laser into an inductively-coupled plasma, with ions dispersed by a sector magnet and integrated in a 7-Faraday multicollector array. Despite large interferences from Yb (16%

Matthew F. Thirlwall; Andrew J. Walder

1995-01-01

74

Characterizing spatial and temporal variability of dissolved gases in aquatic environments with in situ mass spectrometry.  

PubMed

The TETHYS mass spectrometer is intended for long-term in situ observation of dissolved gases and volatile organic compounds in aquatic environments. Its design maintains excellent low mass range sensitivity and stability during long-term operations, enabling characterization of low-frequency variability in many trace dissolved gases. Results are presented from laboratory trials and a 300-h in situ trial in a shallow marine embayment in Massachusetts, U.S.A. This time series consists of over 15000 sample measurements and represents the longest continuous record made by an in situ mass spectrometer in an aquatic environment. These measurements possess sufficient sampling density and duration to apply frequency analysis techniques for study of temporal variability in dissolved gases. Results reveal correlations with specific environmental periodicities. Numerical methods are presented for converting mass spectrometer ion peak ratios to absolute-scale dissolved gas concentrations across wide temperature regimes irrespective of ambient pressure, during vertical water column profiles in a hypoxic deep marine basin off the coast of California, U.S.A. Dissolved oxygen concentration values obtained with the TETHYS instrument indicate close correlation with polarographic oxygen sensor data across the entire depth range. These methods and technology enable observation of aquatic environmental chemical distributions and dynamics at appropriate scales of resolution. PMID:19673300

Camilli, Richard; Duryea, Anthony N

2009-07-01

75

Dating the age of a nuclear event by gamma spectrometry.  

PubMed

The age of a nuclear event can be determined by measuring the activity of two fission products. The event studied was a short irradiation, of a small sample of uranium, in a nuclear reactor. Two types of a clock were investigated: non-isobaric and isobaric parent-daughter fission products. Measurements of the source by gamma spectrometry yielded very good agreement between true and measured ages. The accuracy of each clock and the upper and lower age limits of applicability were studied. PMID:14987642

Nir-El, Y

76

The laser ablation ion funnel: Sampling for in situ mass spectrometry on Mars  

NASA Astrophysics Data System (ADS)

A considerable investment has been made by NASA and other space agencies to develop instrumentation suitable for in situ analytical investigation of extra terrestrial bodies including various mass spectrometers (time-of-flight, quadrupole ion trap, quadrupole mass filters, etc.). However, the front-end sample handling that is needed to collect and prepare samples for interrogation by such instrumentation remains underdeveloped. Here we describe a novel approach tailored to the exploration of Mars where ions are created in the ambient atmosphere via laser ablation and then efficiently transported into a mass spectrometer for in situ analysis using an electrodynamic ion funnel. This concept would enable elemental and isotopic analysis of geological samples with the analysis of desorbed organic material a possibility as well. Such an instrument would be suitable for inclusion on all potential missions currently being considered such as the Mid-Range Rover, the Astrobiology Field Laboratory, and Mars Sample Return (i.e., as a sample pre-selection triage instrument), among others.

Johnson, Paul V.; Hodyss, Robert; Tang, Keqi; Brinckerhoff, William B.; Smith, Richard D.

2011-04-01

77

In situ atom trapping of Bi on W-coated slotted quartz tube flame atomic absorption spectrometry and interference studies  

NASA Astrophysics Data System (ADS)

Analytical performances of metal coated slotted quartz tube flame atomic absorption spectrometry (SQT-FAAS) and slotted quartz tube in situ atom trapping flame atomic absorption spectrometry (SQT-AT-FAAS) systems were evaluated for determination of Bi. Non-volatile elements such as Mo, Zr, W and Ta were tried as coating materials. It was observed that W-coated SQT gave the best sensitivity for the determination of Bi for SQT-FAAS and SQT-AT-FAAS. The parameters for W-coated SQT-FAAS and W-coated SQT-AT-FAAS were optimized. Sensitivity of FAAS for Bi was improved as 4.0 fold by W-coated SQT-FAAS while 613 fold enhancement in sensitivity was achieved by W-coated SQT-AT-FAAS using 5.0 min trapping with respect to conventional FAAS. MIBK was selected as organic solvent for the re-atomization of Bi from the trapping surface. Limit of detection values for W-coated SQT-FAAS and W-coated SQT-AT-FAAS was obtained as 0.14 ?g mL- 1 and 0.51 ng mL- 1, respectively. Linear calibration plot was obtained in the range of 2.5-25.0 ng mL- 1 for W-coated SQT-AT-FAAS. Accuracy of the W-coated SQT-AT-FAAS system was checked by analyzing a standard reference material, NIST 1643e.

K?l?nç, Ersin; Bak?rdere, Sezgin; Ayd?n, F?rat; Ataman, O. Yavuz

2013-11-01

78

The quality control in the production of spiked reference materials for gamma-ray spectrometry  

Microsoft Academic Search

Following a EUROMET project for the development of a range of spiked reference materials for gamma-ray spectrometry, a number of new techniques were adopted at ENEA for the routine production of these materials. A quality control of the produced samples was simultaneously started. It is based on HPGe gamma-ray spectrometry of the different samples in Marinelli beaker measuring geometry. Within

Pierino De Felice; Dadong Iskandar; Aldo Fazio; Roberto Biagini

1998-01-01

79

In situ identification and localization of IGHA2 in the breast tumor microenvironment by mass spectrometry.  

PubMed

Modifications in the tumor microenvironment (TME) play a major role in the establishment, progression, and metastasis of cancer. Matrix-assisted laser desorption/ionization-mass spectrometry imaging (MALDI-MSI) is a powerful technique that enables the simultaneous identification and localization of biological compounds within tissues. To detect markers of early TME remodeling in invasive breast cancer, we used MALDI-MSI to compare the molecular profiles of tissues from the breast cancer interface zone, tumor zone, and normal-tissue zone. Using direct-tissue MALDI tandem mass spectrometry (MS/MS), we identified immunoglobulin heavy constant alpha 2 (IGHA2) as a new, zone-specific protein in the breast TME. The zone-specific expression of IGHA2 was verified by immunoblotting and immunohistochemical analysis. IGHA2 expression was consistently positive in tumor cells that were metastatic to regional nodes, with intense expression along the cytoplasmic borders. As a factor related to an increased percentage of nodes with tumor metastasis, IGHA2 expression was upregulated 3.745-fold in cases with an increased number of cancerous nodes (p = 0.0468). Our results provide the first evidence of IGHA2 as a marker of the early process of TME remodeling in invasive breast cancer. Furthermore, IGHA2 may be a novel marker for regional metastases in the lymph nodes of patients with breast cancer. PMID:22894699

Kang, Suki; Maeng, Heysun; Kim, Baek Gil; Qing, Gao Ming; Choi, Yoon Pyo; Kim, Hak Yong; Kim, Pan Soo; Kim, Yangsun; Kim, Young Hwan; Choi, Young Deuk; Cho, Nam Hoon

2012-08-22

80

Evaluation of in situ electrodeposition technique in electrothermal atomic absorption spectrometry.  

PubMed

Conventional electrothermal atomic absorption spectrometric (ETAAS) equipment was extensively modified to enable automated in situ electrodeposition. The original autosampler injection Teflon capillary was replaced by a composite Pt/Teflon capillary which served as an anode in the electrodeposition circuit. Incorporation of a peristaltic pump and of a three-way solenoid under computer control into the sample dispenser circuit provided all necessary steps for automated electrodeposition-ETAAS determination. The automated sequence controlled addition of Pd modifier and of the analyte, electrolysis, withdrawal of spent electrolyte, rinsing, drying and atomization. Performance of the system was evaluated by analyzing Pb in 3% m/v NaCl. Optimization using factorial design yielded 3sigma detection limit of 20 pg Pb and reproducibility of 1.0-1.4% (for constant current electrodeposition), these values being superior to the results of conventional ETAAS of Pb in 0.5% m/v NaCl. Sensitivity of Pb determination is not affected by NaCl, NaOH, NaNO3 and NH4H2PO4, up to 4.6% m/v, demonstrating efficient matrix removal in the electrodeposition step. PMID:12705390

Krenzelok, Milan; Rychlovsky, Petr; Volny, Michael; Matousek, Jaroslav P

2003-03-01

81

In situ monitoring of powder blending by non-invasive Raman spectrometry with wide area illumination.  

PubMed

A 785nm diode laser and probe with a 6mm spot size were used to obtain spectra of stationary powders and powders mixing at 50rpm in a high shear convective blender. Two methods of assessing the effect of particle characteristics on the Raman sampling depth for microcrystalline cellulose (Avicel), aspirin or sodium nitrate were compared: (i) the information depth, based on the diminishing Raman signal of TiO(2) in a reference plate as the depth of powder prior to the plate was increased, and (ii) the depth at which a sample became infinitely thick, based on the depth of powder at which the Raman signal of the compound became constant. The particle size, shape, density and/or light absorption capability of the compounds were shown to affect the "information" and "infinitely thick" depths of individual compounds. However, when different sized fractions of aspirin were added to Avicel as the main component, the depth values of aspirin were the same and matched that of the Avicel: 1.7mm for the "information" depth and 3.5mm for the "infinitely thick" depth. This latter value was considered to be the minimum Raman sampling depth when monitoring the addition of aspirin to Avicel in the blender. Mixing profiles for aspirin were obtained non-invasively through the glass wall of the vessel and could be used to assess how the aspirin blended into the main component, identify the end point of the mixing process (which varied with the particle size of the aspirin), and determine the concentration of aspirin in real time. The Raman procedure was compared to two other non-invasive monitoring techniques, near infrared (NIR) spectrometry and broadband acoustic emission spectrometry. The features of the mixing profiles generated by the three techniques were similar for addition of aspirin to Avicel. Although Raman was less sensitive than NIR spectrometry, Raman allowed compound specific mixing profiles to be generated by studying the mixing behaviour of an aspirin-aspartame-Avicel mixture. PMID:23291440

Allan, Pamela; Bellamy, Luke J; Nordon, Alison; Littlejohn, David; Andrews, John; Dallin, Paul

2012-12-13

82

Quantitation of parent drug and its unstable metabolites by in situ coulometric oxidation and liquid chromatography-tandem mass spectrometry.  

PubMed

Recent FDA and ICH guidances on safety testing of drug metabolites have challenged the way we traditionally think about quantitative bioanalytical methods. Such assays, in general, require a reference standard for each analyte to construct calibration curves and prepare quality control samples. However, early in the drug development process, metabolite standards may not be readily available, and if they are inherently unstable, they are difficult to synthesize or purify. In this paper, we describe a novel in-line method for producing and then quantifying a very unstable metabolite which is based upon the in situ postcolumn coulometric oxidation of the parent drug. Lacking any metabolite standards, the feasibility of simultaneously quantifying a development drug (compound A) and its unstable hydroxylated metabolites (metabolite B) was investigated. Reference standards for these ostensibly major human metabolites could not be reliably obtained due to rapid degradation upon purification and/or subsequent storage. Following high-performance liquid chromatography (HPLC) separation, parent drug and its [(13)C(3)-(15)N] isotopically labeled internal standard were quantitatively converted to equal amounts of a diastereomeric pair of hydroxylated metabolites using a postcolumn coulometric electrochemical cell before reaching the mass spectrometer. The concentration of the injected parent (which is equal to the total concentration of the in-line generated metabolites since the conversion to metabolite is quantitative) and the tandem mass spectrometry (MS/MS) signals of the electrochemically generated metabolites were used to construct a calibration curve for quantifying both the parent drug and its hydroxylated metabolites. Plasma extracts from humans dosed with compound A contained chromatographically distinct liquid chromatography-mass spectrometry (LC-MS) signals (m/z 538) for in vivo formed hydroxylated metabolites and the electrochemically oxidized parent drug which had been converted in-line into its chemically identical twin. Both peaks in this study sample could be quantified using a single calibration curve obtained under the same coulometric conditions using known amounts of the parent drug. Although no attempt was made to fully validate a bioanalytical method, the practicality of this in situ quantification approach was further confirmed by the preliminary bioanalytical analysis of a selection of plasma samples collected following oral administration (50 mg) of compound A in a clinical study. PMID:21105697

Tong, Wei; Chowdhury, Swapan K; Su, Ai-Duen; Alton, Kevin B

2010-11-24

83

Radioactivity Levels and Gamma-Ray Dose Rate in Soil Samples from Kohistan (Pakistan) Using Gamma-Ray Spectrometry  

Microsoft Academic Search

The analysis of naturally occurring radionuclides (226Ra, 232Th and 40K) and an anthropogenic radionuclide 137Cs is carried out in some soil samples collected from Kohistan district of N.W.F.P. (Pakistan), using gamma-ray spectrometry. The gamma spectrometry is operated using a high purity Germanium (HPGe) detector coupled with a computer based high resolution multi channel analyzer. The specific activity in soil ranges

M. Khan Hasan; M. Ismail; K. Khan; P. Akhter

2011-01-01

84

Calibrated In Situ Measurement of UT/LS Water Vapor Using Chemical Ionization Mass Spectrometry  

NASA Astrophysics Data System (ADS)

Over the past several decades there has been considerable disagreement among in situ water vapor measurements by different instruments at the low part per million (ppm) mixing ratios found in the upper troposphere and lower stratosphere (UT/LS). These discrepancies contribute to uncertainty in our understanding of the microphysics related to cirrus cloud particle nucleation and growth and affect our ability to determine the effect of climate changes on the radiatively important feedback from UT/LS water vapor. To address the discrepancies observed in measured UT/LS water vapor, a new chemical ionization mass spectrometer (CIMS) instrument has been developed for the fast, precise, and accurate measurement of water vapor at low mixing ratios. The instrument utilizes a radioactive ? particle source to ionize a flow of sample air drawn into the instrument. A cascade of ion-molecule reactions results in the production of protonated water ions proportional to the water vapor mixing ratio that are then detected by the mass spectrometer. The multi-step nature of the ionization mechanism results in a non-linear sensitivity to water vapor, necessitating calibration across the full range of values to be measured. To accomplish this calibration, we have developed a novel calibration scheme using catalytic oxidation of hydrogen to produce well-defined water vapor mixing ratios that can be introduced into the instrument inlet during flight. The CIMS instrument was deployed for the first time aboard the NASA WB-57 high altitude research aircraft during the Mid-latitude Airborne Cirrus Properties Experiment (MACPEX) mission in March and April 2011. The sensitivity of the instrument to water vapor was calibrated every ~45 minutes in flight from < 1 to 150 ppm. Analysis of in-flight data demonstrates a typical sensitivity of 2000 Hz/ppm at 4.5 ppm with a signal to noise ratio (2 ?) > 50 for a 1 second measurement. The instrument and its calibration system performed successfully in 7 flights during the MACPEX mission, sampling water vapor mixing ratios as low as 4 ppm in stratospheric air. A comparison of the new measurement with other measurements on board the aircraft is expected to help resolve the long-standing differences in low water measurements in the lower stratosphere.

Thornberry, T. D.; Rollins, A.; Gao, R.; Watts, L. A.; Ciciora, S. J.; McLaughlin, R. J.; Fahey, D. W.

2011-12-01

85

High-speed tandem mass spectrometric in situ imaging by nanospray desorption electrospray ionization mass spectrometry.  

PubMed

Nanospray desorption electrospray ionization (nano-DESI) combined with tandem mass spectrometry (MS/MS), high-resolution mass analysis of the fragment ions (m/?m = 17?500 at m/z 200), and rapid spectral acquisition enabled simultaneous imaging and identification of a large number of metabolites and lipids from 92 selected m/z windows (±1 Da) with a spatial resolution of better than 150 ?m. Mouse uterine sections of implantation sites on day 6 of pregnancy were analyzed in the ambient environment without any sample pretreatment. MS/MS imaging was performed by scanning the sample under the nano-DESI probe at 10 ?m/s, while higher-energy collision-induced dissociation (HCD) spectra were acquired for a targeted inclusion list of 92 m/z values at a rate of ?6.3 spectra/s. Molecular ions and their corresponding fragments, separated by high-resolution mass analysis, were assigned on the basis of accurate mass measurement. Using this approach, we were able to identify and image both abundant and low-abundance isobaric and isomeric species within each m/z window. MS/MS analysis enabled efficient separation and identification of isomeric and isobaric phospholipids that are difficult to separate in full-scan mode. Furthermore, we identified several metabolites associated with early pregnancy and obtained the first 2D images of these molecules. PMID:24040919

Lanekoff, Ingela; Burnum-Johnson, Kristin; Thomas, Mathew; Short, Joshua; Carson, James P; Cha, Jeeyeon; Dey, Sudhansu K; Yang, Pengxiang; Prieto Conaway, Maria C; Laskin, Julia

2013-10-03

86

In situ identification of plant-invasive bacteria with MALDI-TOF mass spectrometry.  

PubMed

Rhizobia form a disparate collection of soil bacteria capable of reducing atmospheric nitrogen in symbiosis with legumes. The study of rhizobial populations in nature involves the collection of large numbers of nodules found on roots or stems of legumes, and the subsequent typing of nodule bacteria. To avoid the time-consuming steps of isolating and cultivating nodule bacteria prior to genotyping, a protocol of strain identification based on the comparison of MALDI-TOF MS spectra was established. In this procedure, plant nodules were considered as natural bioreactors that amplify clonal populations of nitrogen-fixing bacteroids. Following a simple isolation procedure, bacteroids were fingerprinted by analysing biomarker cellular proteins of 3 to 13 kDa using Matrix Assisted Laser Desorption/Ionization Time of Flight (MALDI-TOF) mass spectrometry. In total, bacteroids of more than 1,200 nodules collected from roots of three legumes of the Phaseoleae tribe (cowpea, soybean or siratro) were examined. Plants were inoculated with pure cultures of a slow-growing Bradyrhizobium japonicum strain G49, or either of two closely related and fast-growing Sinorhizobium fredii strains NGR234 and USDA257, or with mixed inoculants. In the fully automatic mode, correct identification of bacteroids was obtained for >97% of the nodules, and reached 100% with a minimal manual input in processing of spectra. These results showed that MALDI-TOF MS is a powerful tool for the identification of intracellular bacteria taken directly from plant tissues. PMID:22615938

Ziegler, Dominik; Mariotti, Anna; Pflüger, Valentin; Saad, Maged; Vogel, Guido; Tonolla, Mauro; Perret, Xavier

2012-05-17

87

In Situ Identification of Plant-Invasive Bacteria with MALDI-TOF Mass Spectrometry  

PubMed Central

Rhizobia form a disparate collection of soil bacteria capable of reducing atmospheric nitrogen in symbiosis with legumes. The study of rhizobial populations in nature involves the collection of large numbers of nodules found on roots or stems of legumes, and the subsequent typing of nodule bacteria. To avoid the time-consuming steps of isolating and cultivating nodule bacteria prior to genotyping, a protocol of strain identification based on the comparison of MALDI-TOF MS spectra was established. In this procedure, plant nodules were considered as natural bioreactors that amplify clonal populations of nitrogen-fixing bacteroids. Following a simple isolation procedure, bacteroids were fingerprinted by analysing biomarker cellular proteins of 3 to 13 kDa using Matrix Assisted Laser Desorption/Ionization Time of Flight (MALDI-TOF) mass spectrometry. In total, bacteroids of more than 1,200 nodules collected from roots of three legumes of the Phaseoleae tribe (cowpea, soybean or siratro) were examined. Plants were inoculated with pure cultures of a slow-growing Bradyrhizobium japonicum strain G49, or either of two closely related and fast-growing Sinorhizobium fredii strains NGR234 and USDA257, or with mixed inoculants. In the fully automatic mode, correct identification of bacteroids was obtained for >97% of the nodules, and reached 100% with a minimal manual input in processing of spectra. These results showed that MALDI-TOF MS is a powerful tool for the identification of intracellular bacteria taken directly from plant tissues.

Pfluger, Valentin; Saad, Maged; Vogel, Guido; Tonolla, Mauro; Perret, Xavier

2012-01-01

88

In situ measurements of atmospheric nitrous acid by chemical ionization mass spectrometry using chloride ion transfer reactions.  

PubMed

Recently, chemical ionization mass spectrometry (CIMS) has been widely applied to the in situ measurements of atmospheric trace species. In this article, we propose a new chemical ionization scheme using a chloride ion transfer reaction from SO(2)Cl(-) as the reagent ion and discuss the applicability of this technique to the detection of nitrous acid (HONO) in the atmosphere. From laboratory investigations, the detection sensitivity was found to depend on the flow rate of SO(2) introduced into the ion source region and the pressure inside the chemical ionization region, which suggests that the chemical ionization reaction is reversible. The detection sensitivity was well described in terms of the forward and backward rates. The present limit of detection is estimated to be 60 parts per trillion by volume (pptv) for an integration time of 1 min. Improvement of the CIMS instrument would enable the measurements of the daytime level of HONO, which might be less than 50 pptv. In addition, the possibility of the interference is discussed from thermodynamic considerations based on ab initio calculations, and the effects of the sampling artifacts are experimentally quantified. PMID:19746928

Hirokawa, Jun; Kato, Takehiro; Mafuné, Fumitaka

2009-10-15

89

Headspace solid phase microextraction in-situ supercritical fluid extraction coupled to gas chromatography–tandem mass spectrometry for simultaneous determination of perfluorocarboxylic acids in sediments  

Microsoft Academic Search

Headspace solid phase microextraction (HS-SPME) in-situ supercritical fluid extraction (SFE) was investigated for the determination of trace amounts of perfluorocarboxylic acids (PFCAs) in sediments. Quantitation was performed by using gas chromatography coupled to negative chemical ionization–tandem mass spectrometry (GC–NCI–MS\\/MS). The optimum conditions of HS-SPME following SFE were obtained using 500?L n-butanol as a derivatization reagent in supercritical carbon dioxide with

Wen-Lin Liu; Bao-Huey Hwang; Zu-Guang Li; Jen-Fon Jen; Maw-Rong Lee

2011-01-01

90

In situ trace-element analysis of individual silicate melt inclusions by laser ablation microprobe-inductively coupled plasma-mass spectrometry (LAM-ICP-MS)  

Microsoft Academic Search

This paper reports the successful application of laser ablation microprobe-inductively coupled plasma-mass spectrometry (LAM-ICP-MS) to the in situ analysis of a diverse suite of twenty trace elements including Zr, Hf, Nb, Ta, Y, and REEs, in individual silicate melt inclusions in phenocrysts from Fantale volcano, Ethiopia. The UV laser, a frequency quadrupled Nd: YAG operating at 266 nm, significantly improves

R. P. Taylor; S. E. Jackson; H. P. Longerich; J. D. Webster

1997-01-01

91

Automated determination of tin by hydride generation using in situ trapping on stable coatings in graphite furnace atomic absorption spectrometry  

NASA Astrophysics Data System (ADS)

Conditions have been studied for the determination of Sn by coupling of hydride generation and graphite furnace atomic absorption spectrometry. Sequestering and in situ concentration of Sn hydride in the graphite furnace requires just a single application of a long-term stable trapping reagent for automated analyses. In a systematic study it is shown that effective trapping of stannane is possible on graphite tubes or platforms coated with a carbide-forming element such as Zr, Nb, Ta, or W at trapping temperatures of 500 to 600°C. Trapping temperatures should not be higher than 600°C (the "critical temperature") because otherwise at temperatures higher than 700°C errors in absorbance values could occur by an adsorptive "carry-over effect". Signal stability and reproducibility are tested over more than 400 complete trapping and atomization cycles, and a precision of 2% is observed. Narrow peaks are obtained for all coatings except for Nb- and Ta-coated platforms where double peaks occur. Ir- or Pd/Ir-coated surfaces allow trapping of stannane at lower temperatures but the signal stability (especially in the case of Pd/Ir coating) is lower than with the carbide-forming element coatings. The highest sensitivity is found for Zr- and W-coated tubes with a characteristic mass of about 17 and 20 pg, respectively, and the calibration curves are linear up to 2 ng Sn on Zr-treated tubes (peak height) and 4 ng on Zr-coated platforms (integrated absorbance) using the 286.3 nm line. The detection limit is 25 pg for a 1 ml sample volume, and the reagent blank is still significant with the purest available chemicals. The method is tested by determination of Sn in low alloy steel samples.

Haug, Hermann O.; Yiping, Liao

1995-09-01

92

In situ diagnostics of the decomposition of silacyclobutane on a hot filament by vacuum ultraviolet laser ionization mass spectrometry.  

PubMed

The gas-phase reaction products of silacyclobutane (SCB) and 1, 1-dideuterio-silacyclobutane (SCB-d(2)) from a hot-wire chemical vapor deposition (HWCVD) chamber were diagnosed in situ using vacuum ultraviolet (VUV) laser single-photon ionization (SPI) coupled with time-of-flight (TOF) mass spectrometry. The SCB molecule was found to decompose at a filament temperature as low as 900 degrees C. Both Si- (silylene, methylsilylene, and silene) and C-containing (ethene and propene) species were produced from the SCB decomposition on the filament. Ethene and propene were detected by the mass spectrometer. It is demonstrated that the formation of ethene is favored over that of propene. The experimental study of hot-wire decomposition of SCB-d(2) shows that propene is most likely produced by a process that is initiated by a 1,2-H(D) migration to form n-propylsilylene, followed by an equilibration with silacyclopropane, which then decomposes to propene. The detection of ethene in our experiment indicates that a competitive route of fragmentation exists for SCB decomposition on the filament. It has been shown that this competitive route occurs without H/D scrambling. The highly reactive silylene, silene, and methylsilylene species produced from SCB decomposition underwent either insertion reactions into the Si-H bonds of the parent molecule or pi-type addition reaction across the double and triple CC bonds. The dimerization product of silene, 1,3-disilacyclobutane, at m/z = 88 was also observed. PMID:17285587

Shi, Y J; Lo, B; Tong, L; Li, X; Eustergerling, B D; Sorensen, T S

2007-05-01

93

Coincidence-summing correction equations in gamma-ray spectrometry with p-type HPGedetectors  

NASA Astrophysics Data System (ADS)

Equations to compute ?-? and ?-XK coincidence-summing corrections in gamma-ray spectrometry with p-type HPGe detectors are reported. For point sources only full-energy-peak and total efficiencies are needed.

Tomarchio, E.; Rizzo, S.

2011-03-01

94

The limits of decision, detection, and determination in anti-Compton gamma-ray spectrometry  

Microsoft Academic Search

The improvement in the limits of decision, detection, and determination effected by anti-Compton gamma-ray spectrometry are considered. A simple procedure for the experimental determination is presented.

H. A. Das

1986-01-01

95

Optimization of nickel tetracarbonyl generation and nickel in situ trapping within a transversely heated graphite furnace for atomic absorption spectrometry  

Microsoft Academic Search

The efficiency of nickel tetracarbonyl generation and of in situ trapping within a transversely heated graphite furnace was studied. The influence of experimental parameters of the flow injection generation system and in situ collection procedure for atomic absorption spectrometric determination of nickel, i.e. pH of reaction mixture, concentration of sodium tetrahydroborate solution, reaction temperature, concentration of various electrolytes, several ‘heavy

Bohumil Do?ekal; Petr Marek

2000-01-01

96

In-flight, online processing and mapping of airborne gamma spectrometry data  

Microsoft Academic Search

Airborne gamma spectrometry is a technique especially useful for environmental monitoring and emergency preparedness. Because time is a critical factor in emergency response a fast data processing and mapping software is needed, which also supports online monitoring and data processing features. Therefore a new online data processing and mapping software was developed, which also displays successfully the gamma spectra, the

Benno Bucher; Ladislaus Rybach; Georg Schwarz

2005-01-01

97

EFFTRAN—A Monte Carlo efficiency transfer code for gamma-ray spectrometry  

Microsoft Academic Search

An implementation of the efficiency transfer method for cylindrical samples in gamma-ray spectrometry is presented, based on a Monte Carlo integration of the interaction probabilities of gamma rays over the detector and sample volumes. This approach makes it possible for the computer code to be relatively straightforward to write and the speed of the calculation to be adequate for routine

Tim Vidmar

2005-01-01

98

Corrections for self-attenuation in gamma-ray spectrometry of bulk samples  

Microsoft Academic Search

On the basis of the measurement of over 70 radioactive standard bulk sources with different matrix density and different shapes, the gamma-ray self-attenuation corrections needed in activity determination by means of gamma-ray spectrometry are evaluated. The full-energy peak efficiency dependence on the density, and the self-attenuation correction dependence on the photon energy are described.

T Boshkova; L Minev

2001-01-01

99

Quantification of uranium-238 in environmental samples using gamma-ray spectrometry  

NASA Astrophysics Data System (ADS)

A large number of environmental samples are routinely measured world-wide using gamma-ray spectrometry some of its assets being easy sample preparation and comprehensive data for many radionu-clides in one analysis. Although other techniques can be considered more suitable for analysing 238U in environmental samples, it is also routinely done by gamma-ray spectrometry. One mainly uses ?-ray emissions following the decay of the first daughter, 234Th, for determining the 238U activity. However, the low-energy gamma-rays at 63 keV and 92.5 keV are very difficult to quantify in a robust way due to high attenuation and interferences. This paper quantifies parameters affecting the possibility of making robust quantification of 238U via 234Th using gamma-ray spectrometry. It addresses the use of correct decay data, suitable detectors, optimised sample size, enhanced spectral amplification, correction for peak interferences and control of background.

Hult, M.; Andreotti, E.; González de Orduña, R.; Pommé, S.; Yeltepe, E.

2012-04-01

100

MRI Versus Breast-Specific Gamma Imaging (BSGI) in Newly Diagnosed Ductal Cell Carcinoma-in-situ: A Prospective Head-to-Head Trial  

Microsoft Academic Search

Background  Mammography remains the standard imaging technique for the diagnosis of ductal carcinoma-in-situ (DCIS). Functional breast\\u000a imaging, including breast magnetic resonance imaging (MRI), has known limitations in evaluating DCIS. To date, there are limited\\u000a data on the utility of breast-specific gamma imaging (BSGI) in DCIS. We sought to prospectively compare the sensitivity of\\u000a BSGI to MRI in newly diagnosed DCIS patients.

Jessica L. Keto; Laurie Kirstein; Diana P. Sanchez; Tamara Fulop; Laura McPartland; Ilona Cohen; Susan K. Boolbol

101

Coincidence summing corrections for positron emitters in germanium gamma spectrometry  

NASA Astrophysics Data System (ADS)

For positron emitters, 511 keV annihilation quanta are in coincidence with other gamma rays in the decay scheme. If the positrons are not localized at the point of decay, annihilation quanta will be produced at a site some distance from the point of emission. The magnitude of the summing coincidence effect will depend upon the position of annihilation. A method for determining the magnitude of the summing effect for a single gamma of energy E in coincidence with the annihilation gammas from non-localized positrons has been developed which makes use of the counting data for the full energy peaks for both the gamma ray (E) and the 511 keV annihilation gammas. With this data and efficiency calibration data one can determine the average total efficiency for the annihilation positions from which 511 keV gammas originate, and thereby obtain the summing correction factor, SCF, for gamma ray (E). Application of the method to a 22Na NIST standard gave excellent agreement of observed emission rates for the 1275 keV gamma with the NIST value for wide ranging degrees of positron localization having summing correction factors ranging from 1.021 to 1.505. The method was also applied successfully to 58Co in neutron-irradiated nickel foils. The method shows promise as a check on the accuracy of the efficiency calibration for a particular detector geometry at the 511 keV energy and energies for other gammas associated with positron emission.

Richardson, A. E.; Sallee, W. W.

1990-12-01

102

Miniaturized laser-induced plasma spectrometry for planetary in situ analysis – The case for Jupiter’s moon Europa  

Microsoft Academic Search

Jupiter’s icy moon Europa is one of most promising places in our Solar System where possible extraterrestrial life forms could exist either in the past or even presently. The Europa Lander mission, an exciting part of the international Europa Jupiter System Mission (EJSM\\/Laplace), considers in situ planetary exploration of the moon. The distance of Europa from the Earth and the

S. G. Pavlov; E. K. Jessberger; H.-W. Hübers; S. Schröder; I. Rauschenbach; S. Florek; J. Neumann; H. Henkel; S. Klinkner

2011-01-01

103

Quick identification of polycarboxylates in laundry detergents by in situ pyrolysis-methylation gas chromatography\\/mass spectrometry  

Microsoft Academic Search

This report summarizes method development for the identification of polycarboxylates using in situ pyrolysis-methylation gas chromatography (GC) with mass detection. Ground detergent products are dissolved in water together with a methylation reagent, tetramethylammonium hydroxide. The solution is centrifuged and an aliquot of supernatant is pyrolyzed after water is evaporated. Key fragments separated via GC are detected with a mass selective

Akihiko Kawauchi; Toshihiko Uchiyama

1998-01-01

104

On line gamma-ray spectrometry at open sea  

Microsoft Academic Search

Set up and application of a stationary monitoring network for measuring specific ?- activities in the Aegean Sea are described. Three NaI scintillator based spectrometers have been used to detect the gamma rays. The gross counting rate of each system was found to be nearly constant, when there was no rainfall. The volumetric activity of the natural gamma-ray emitter 40K

C. Tsabaris; D. Ballas

2005-01-01

105

Isotopic analysis of uranium in U 3O 8 by passive gamma-ray spectrometry  

Microsoft Academic Search

Passive gamma-ray spectrometry was applied to analyze the isotopic composition of uranium in U3O8. Depleted and enriched U3O8 standard reference materials were used to calibrate the system. An independent calibration was performed by standard gamma-ray point sources. U3O8 SRM samples of the 950 series were analyzed. The present results show that the isotopic abundances of 235U in SRMs 950, 950a

Y Nir-El

2000-01-01

106

Coincidence Summing Corrections in Gamma-Ray Spectrometry Using GEANT4 Code  

Microsoft Academic Search

In this paper coincidence summing corrections in gamma-ray spectrometry have been analyzed in depth. Experimental setup included a n-type germanium detector and two efficient geometries of measurement (Marinelli beaker and air filter) calibrated with multi gamma radionuclides in the energy range of 40-1500 keV. Monte Carlo simulations were carried out using the GEANT4 code in order to develop this work.

Santiago Hurtado; Rafael Garcia-Tenorio; Manuel Garcia-Leon

2009-01-01

107

Maintaining Accuracy in Gamma-Ray Spectrometry at High Count Rates  

Microsoft Academic Search

Gamma-ray spectrometry losses through pulse processing dead time and pile-up are best assayed with an external pulse technique. In this work, the virtual pulse generator technique as implemented commercially with the Westphal loss free counting (LFC) module is set up and tested with four high resolution gamma-ray spectrometers. Dual source calibration and decaying source techniques are used in the evaluation

R. Zeisler

2000-01-01

108

Automated construction of detector models for efficiency interpolation in gamma-ray spectrometry  

Microsoft Academic Search

A method was developed for automated construction of detector models in gamma-ray spectrometry, which can be used in Monte Carlo calculations of efficiency calibration curves. Full-energy peak efficiencies were first measured for different gamma-ray energies and for a given sample–detector arrangement and then calculated by the Monte Carlo method. For these calculations a detector model was employed along with a

T. Vidmar; A. Likar

2002-01-01

109

CdWO\\/sub 4\\/ crystal in gamma-ray spectrometry  

Microsoft Academic Search

The properties of CdWO4 (CWO) crystals in gamma spectrometry were studied. Several small samples of 10times10times3 mm size, typically used in CT X-ray detectors, were tested and then compared to the performance of a larger crystal of 20 mm in diameter and 20 mm in height. The light output, energy resolution, and nonproportionality of the CWO response versus gamma-ray energy,

M. Moszynski; M. Balcerzyk; M. Kapusta; A. Syntfeld; D. Wolski; G. Pausch; J. Stein; P. Schotanus

2005-01-01

110

An improved method for determination of heat production with gamma-ray scintillation spectrometry  

Microsoft Academic Search

Gamma-ray scintillation spectrometry is often the method of choice for determination of the heat-producing elements (HPE's) uranium, thorium and potassium. This article updates the procedure, describing modern equipment and proposing revised measurement calculations and error analysis. New equations for calculating HPE concentrations and applicable errors from gamma-ray spectra allow for standards that contain all three HPE's, rather than requiring that

Richard A. Ketcham

1996-01-01

111

Determination of basic degradation products of chemical warfare agents in water using hollow fibre-protected liquid-phase microextraction with in-situ derivatisation followed by gas chromatography–mass spectrometry  

Microsoft Academic Search

Hollow fibre-protected liquid-phase microextraction (HF-LPME) together with gas chromatography–mass spectrometry was, for the first time, investigated for the in-situ derivatisation and analysis of basic degradation products of chemical warfare agents in water samples. The degradation products studied were those of nerve and blister agents, and a psychotomimetic agent. Extractions with in-situ derivatisation were successfully performed using a mixture of solvent

Hoi Sim Nancy Lee; Mui Tiang Sng; Chanbasha Basheer; Hian Kee Lee

2008-01-01

112

In situ Pb geochronology of zircon with laser ablation–inductively coupled plasma–sector field mass spectrometry  

Microsoft Academic Search

The in situ Pb geochronological capabilities of a laser ablation–inductively coupled plasma–mass spectrometer (LA–ICP–MS) coupling a magnetic sector ICP–MS with a Nd:YAG laser probe working at 213 nm have been tested on three zircon populations with different age (150–294–577 Ma) and radiogenic Pb contents (0.7–10–40 ppm). The influence of scan mode and spatial resolution on age precision and accuracy has

Massimo Tiepolo

2003-01-01

113

In situ kinetic investigations during aluminium nitride purification and crystal growth processes by capillary coupled mass spectrometry  

Microsoft Academic Search

Reaction models in the system Al–N–O–C–H are essential for intelligent purification of aluminium nitride source material and to predict time- and temperature-dependent reduction of oxygen-containing impurities. For several purposes, high purity AlN is needed; consequently it is an important goal to minimize the impurity values to a minimum possible prior to the single crystal growth. For these reasons in situ

C. Guguschev; E. Moukhina; J. Wollweber; A. Dittmar; K. Böttcher; C. Hartmann; S. Golka; R. Fornari

2011-01-01

114

High-pressure xenon detectors for gamma-ray spectrometry  

Microsoft Academic Search

The main results of long-term research on compressed xenon detector properties conducted at the laboratory of cosmic physics of MEPhI are given along with a description of the latest gamma-ray spectrometers based on this work. It is shown that using xenon as working substance, it is possible to create a gamma-ray spectrometer with high energy resolution. The construction and the

V. V. Dmitrenko; V. M. Gratchev; S. E. Ulin; Z. M. Uteshev; K. F. VIasik

2000-01-01

115

ATCA data acquisition system for gamma-ray spectrometry  

Microsoft Academic Search

The gamma-ray spectrometer JET EP2 (Joint European Torus enhancement project 2) project aims to perform high-resolution gamma spectroscopy at very high count rate (up to few MHz). Traditional analogue electronic has count rate and pulse processing limitations (long dead-time, pile-up challenge). Digital pulse processing (DPP) systems have been shown to have better performance than analogue ones for processing neutrons or\\/and

R. C. Pereira; J. Sousa; A. M. Fernandes; F. Patrício; B. Carvalho; A. Neto; C. A. F. Varandas; G. Gorini; M. Tardocchi; D. Gin; A. Shevelev

2008-01-01

116

Analysis for naturally occuring radionuclides at environmental concentrations by gamma spectrometry  

Microsoft Academic Search

The analytical potential of low level, high resolution gamma-ray spectrometry for naturally occurring radionuclides at environmental levels is described, with particular emphasis on detector background levels and sensitivity. Comparisons are drawn between the performance of a specially designed low background detector system, and that of standard off the shelf devices. Sample characteristics, calibration procedures and checks, are described, and empirical

A. S. Murray; R. Marten; A. Johnston; P. Martin

1987-01-01

117

Rock and soil discrimination by low altitude airborne gamma-ray spectrometry in Payne County, Oklahoma  

Microsoft Academic Search

The ability to identify and discriminate rock and soil types from the ; air using gamma spectrometry was investigated in Payne County, Oklahoma. The ; data, which were reduced to concentration values for K, U, and Th, were obtained ; from a helicopter at an average altitude of 75 feet above the ground. The area ; investigated was underlain by

T. F. Schwarzer; J. A. S. Adams

1973-01-01

118

Measurements of Uranium Enrichment by Four Techniques of gamma-Ray Spectrometry.  

National Technical Information Service (NTIS)

Measurements of uranium enrichment with the uses of the LMRI (France) UO sub 2 standards have been made by four techniques of gamma-ray spectrometry, in order to examine measurement characteristics of each technique. The following results were obtained by...

T. Tojo

1983-01-01

119

Application of airborne gamma-ray spectrometry to geoscience in China  

Microsoft Academic Search

In this paper, we discuss the theory, method, instrumentation, surveying techniques, and data processing and interpretation in airborne gamma-ray spectrometry and the new development of its applications to geological mapping, gold and nonferrous metallic deposit prospecting, gas and oil exploration, potash deposit prospecting and uranium deposit prospecting in China.

Ye Zhang; Shengqing Xiong; Tianyou Chen

1998-01-01

120

Metrological characterization of the ADONIS system used in gamma-ray spectrometry  

Microsoft Academic Search

In gamma-ray spectrometry, new acquisition systems based on digital signal processing are now commercially available. In order to determine their performance at high count rates, the Commissariat à l’Energie Atomique (CEA), Laboratoire National Henri Becquerel has tested several of these systems. These tests have clearly shown that the performance levels announced by the manufacturers were generally not met. It was

J. Plagnard; J. Morel; A. Tran Tuan

2004-01-01

121

A new technique for processing airborne gamma ray spectrometry data for mapping low level contaminations  

Microsoft Academic Search

A new technique for processing airborne gamma ray spectrometry data has been developed. It is based on the noise adjusted singular value decomposition method introduced by Hovgaard in 1997. The new technique opens for mapping of very low contamination levels. It is tested with data from Latvia where the remaining contamination from the 1986 Chernobyl accident together with fallout from

H. K Aage; U Korsbech; K Bargholz; J Hovgaard

1999-01-01

122

Determination of sulfur in environmental materials by thermal neutron caputre prompt gamma-ray spectrometry  

Microsoft Academic Search

Thermal neutron induced prompt ..gamma..-ray spectrometry has been investigated as a technique to measure elemental S concentrations in complex materials. Comparison of analytical results of standardized materials shows the method to be accurate. Repeated analyses of 100 mg of elemental S gave a 1 percent standard deviation from the mean. The standard deviation increased with decreasing quantities of S. Standardized

Edward T. Jurney; David B. Curtis; Ernest S. Gladney

1977-01-01

123

Effective thickness of bulk samples in “close” measuring gamma-ray spectrometry  

Microsoft Academic Search

Analyzing the experimentally evaluated self-attenuation correction coefficients needed in activity determination by means of gamma-ray spectrometry, the effective thicknesses of bulk samples of three shapes were evaluated. The effective thicknesses deduced significantly differ from the geometrical sample thicknesses in “close” measuring geometry.

T. Boshkova

2003-01-01

124

Centromere detection in vinblastine- and radiation-induced micronuclei of cytokinesis-blocked mouse cells by using in situ hybridization with a mouse gamma (major) satellite DNA probe  

SciTech Connect

Non-isotopic in situ hybridization using a mouse gamma (major) satellite probe DNA was applied to detect centromeres in micronuclei, which were induced in vitro mouse liver cells by ionizing radiation and by vinblastine sulfate. In a cytokinesis-blocked micronucleus assay a dose-dependent induction of micronuclei was found for both agents. After vinblastine exposure the observed micronuclei showed centromere-positive hybridization signals in an order of magnitude of 70-91%, but after radiation exposure the magnitude was only 10-20%. Since the in situ hybridization technique detects centromeric DNA directly, it can be used in a cytokinesis-blocked micronucleus assay for a rapid and reliable discrimination between aneuploidy-inducing and clastogenic agents.

Salassidis, K.; Huber, R.; Zitzelsberger, H.; Bauchinger, M. (Inst. fuer Strahlenbiologie, Neuherberg (West Germany))

1992-01-01

125

Pulser injection with subsequent removal for gamma-ray spectrometry  

DOEpatents

An improved system for gamma-ray spectroscopy characterized by an interface module that controls the injection of electronic pulses as well as separation logic that enables storage of pulser events in a region of the spectrum of a multichannel analyzer distinct from the region reserved for storage of gamma-ray events. The module accomplishes this by tagging pulser events (high or low) injected into the amplification circuitry, adding an offset to the events so identified at the time the events are at the output of the analog to digital converter, and storing such events in the upper portion of the spectrum stored in the multichannel analyzer. The module can be adapted for use with existing gamma-ray spectroscopy equipment to provide for automatic analyses of radioisotopes. 7 figs.

Hartwell, J.K.; Goodwin, S.G.; Johnson, L.O.; Killian, E.W.

1989-02-01

126

Pulser injection with subsequent removal for gamma-ray spectrometry  

DOEpatents

An improved system for gamma-ray spectroscopy characterized by an interface module that controls the injection of electronic pulses as well as separation logic that enables storage of pulser events in a region of the spectrum of a multichannel analyzer distinct from the region reserved for storage of gamma-ray events. The module accomplishes this by tagging pulser events (high or low) injected into the amplification circuitry, adding an offset to the events so identified at the time the events are at the output of the analog to digital converter, and storing such events in the upper portion of the spectrum stored in the multichannel analyzer. The module can be adapted for use with existing gamma-ray spectroscopy equipment to provide for automatic analyses of radioisotopes.

Hartwell, Jack K. (Idaho Falls, ID); Goodwin, Scott G. (Idaho Falls, ID); Johnson, Larry O. (Blackfoot, ID); Killian, E. Wayne (Idahoe Falls, ID)

1990-01-01

127

A generic approach for the determination of residues of alkylating agents in active pharmaceutical ingredients by in situ derivatization-headspace-gas chromatography-mass spectrometry.  

PubMed

A simple, reliable and fast procedure for the simultaneous determination of residues of some common alkylating agents (AAs), such as mesylates, besylates, tosylates and sulfates, employed in drug synthesis, has been developed by in situ derivatization-headspace-gas chromatography-mass spectrometry. Pentafluorothiophenol is used as a derivatizing agent in different water/dimethyl sulfoxide ratios. Compared to former analytical procedures, this approach returns improvements in analysis time, selectivity, analyte stability and method sensitivity (LOD=0.11 microgg(-1) for methyl tosylate). The method exhibits low matrix dependence, excellent accuracy, precision (R.S.D.=2.8-10% range at 1 microgg(-1)) and robustness through the use of deuterated internal standards. Knowledge of the synthetic route allows a targeted approach to the determination of specific AAs since the procedure does not distinguish between acid species. The procedure was successfully applied to different pharmaceutical matrixes, and is particularly suitable for routine analysis with high sample throughput. PMID:17719195

Alzaga, Roberto; Ryan, Robert W; Taylor-Worth, Karen; Lipczynski, Andrew M; Szucs, Roman; Sandra, Pat

2007-07-20

128

In situ formation of C-glycosides during electrospray ionization tandem mass spectrometry of a series of synthetic amphiphilic cholesteryl polyethoxy neoglycolipids containing N-acetyl-D-glucosamine.  

PubMed

In this communication, the structural analysis of six synthetic O-Linked amphiphilic cholesteryl polyethoxy neoglycolipids containing N-acetyl-D-glucosamine was performed by electrospray ionization mass spectrometry in the positive ion mode, with a QqTOF-MS/MS hybrid instrument. The MS/MS analyses provided evidence for the "in situ" formation, in the collision cell of the tandem mass spectrometer, of an unexpected and unique [C-glycoside]+ product ion, resulting from an ion-molecule reaction between the N-acetyl-D-glucosamine oxonium ion and the neutral cholesta-3,5-diene molecule. Quasi MS3 analysis of this ion resulted in the dissociation of the precursor [C-glycoside]+ ion, which produced the expected third generation N-acetyl-D-glucosamine oxonium and the protonated cholesta-3,5-diene product ions. PMID:15792726

Banoub, Joseph; Boullanger, Paul; Lafont, Dominique; Cohen, Alejandro; El Aneed, Anas; Rowlands, Elizabeth

2005-04-01

129

In situ metathesis ionic liquid formation dispersive liquid-liquid microextraction for copper determination in water samples by electrothermal atomic absorption spectrometry.  

PubMed

In situ synthesis of ionic liquid extractant for dispersive liquid-liquid microextraction (in situ IL DLLME) combined with electrothermal atomic absorption spectrometry (ET AAS) for determination of copper in water samples was developed. Analytical signals were obtained without the back-extraction of copper from the IL phase prior to its determination by AAS. Some essential parameters of the microextraction and detection techniques such as the pH of sample solution, volume of components for in situ synthesis, matrix interferences and main parameters of graphite furnace atomizer have been studied. Under optimal conditions, high extraction efficiency for copper was achieved for the extraction of 0.7µgL(-1) in 10.0mL of sample solution employing 8?L of 1-hexyl-3-methylimidazolium bis[(trifluoromethyl)sulfonyl]imide (HmimNTf2) as the extraction solvent. The detection limit was found as 0.004µgL(-1) with an enrichment factor of 200. The relative standard deviation (RSD) for seven replicate measurements of 0.7µgL(-1) in sample solution was 4%. The accuracy of the proposed method was evaluated by analysis of the Certified Reference Materials: NIST SRM 2709 (San Joaquin Soil), NBS SRM 2704 (Buffalo River Sediment), NRCC DOLT-2 (Dogfish Liver) and NIST SRM 1643e (Trace Element in Water). The measured copper contents in the reference materials were in satisfactory agreement with the certified values. The method was successfully applied to analysis of the tap, lake and mineral water samples. PMID:24054576

Stanisz, Ewa; Zgo?a-Grze?kowiak, Agnieszka

2013-05-02

130

Lecture Notes on Computerized gamma-Ray Spectrometry.  

National Technical Information Service (NTIS)

After considering the basic interactions of photons with matter, which can explain the shape of the gamma-ray spectrum, the principles for computer programs for automatic data treatment are considered. The emphasis is on methods for peak search, for deter...

W. L. Zijp

1984-01-01

131

Airborne gamma-ray spectrometry in uranium exploration  

Microsoft Academic Search

Uranium exploration is of paramount importance to India to maximize the indigeneous resources to meet the ever increasing demand for energy. Comprehensive regional and local zones of uranium mineralization are needed to be resolved. Such data comprise information on radioactivity in various energy ranges and on lithological knowledge. Airborne gamma-ray spectrometric techniques are particularly suited to provide spatial information. This

S. S. Raghuwanshi

1992-01-01

132

Intercomparison of efficiency transfer software for gamma-ray spectrometry  

Microsoft Academic Search

The EUROMET project 428 examines efficiency transfer results for Ge gamma-ray spectrometers when the efficiency is known for a reference point source geometry. For this, different methods are used, such as Monte Carlo simulation or semi-empirical computation. The exercise compares the application of these methods to the same selected experimental cases to determine the usage limitations versus the requested accuracy.

M. C. Lépy; T. Altzitzoglou; D. Arnold; F. Bronson; R. Capote Noy; M. Décombaz; F. De Corte; R. Edelmaier; E. Herrera Peraza; S. Klemola; M. Korun; M. Kralik; H. Neder; J. Plagnard; S. Pommé; J. de Sanoit; O. Sima; F. Ugletveit; L. Van Velzen; T. Vidmar

2001-01-01

133

Simultaneous Estimation of Pu and Fission Products by Gamma Spectrometry.  

National Technical Information Service (NTIS)

A gamma spectrometric method is described for the simultaneous estimation of Pu and fission products using a 62cc intrinsic germanium detector coupled to a 4K MCA. The 120 KeV peak of /sup 239/Pu was employed for the assay of plutoniu m. The low energy 51...

P. V. Achuthan R. G. Bhogale A. Ramanujam M. R. Iyer D. N. Sharma

1988-01-01

134

A laboratory pilot for in situ analysis of refractory organic matter in Martian soil by gas chromatography mass spectrometry  

NASA Astrophysics Data System (ADS)

The “Sample Analysis at Mars” project (SAM) is a multi purpose space experiment devoted to the in situ analysis of the Martian environment. It is designed to run multiple analyses on gas or solid samples, and eventually liquids, and is proposed to be part of the scientific payload of the future NASA Mars Science Laboratory 2009 (MSL 2009). One of its main objectives is to discover traces of a past or present life on the planet. Here is presented the laboratory pilot system for automated analysis of possibly refractory organic matter in Martian soil samples, which corresponds to a part of the Chemical Separation and Processing Laboratory of SAM experiment. It is a one-pot process performing, in a row, extraction, derivatization and transfer of the organic molecules to a gas chromatography mass spectrometer for analysis. We have shown that such a system is able to detect 10 pmol of refractive material from a 100 mg sample of Atacama desert, which is a good Martian analogue for organics analysis. This pilot can handle and allow the analysis of a wide range of molecules, including carboxylic and amino acids, which are of utmost interest for the goal which is aimed. Further on, such a system is universal, and could be taken as a good start for any future in situ exploratory space mission.

Meunier, Damein; Sternberg, Robert; Mettetal, Franck; Buch, Arnaud; Coscia, David; Szopa, Cyril; Rodier, Claude; Coll, Patrice; Cabanec, Michael; Raulin, François

135

Basic characterization of highly enriched uranium by gamma spectrometry  

Microsoft Academic Search

Gamma-spectrometric methods suitable for the characterization of highly enriched uranium samples encountered in illicit trafficking of nuclear materials are presented. In particular, procedures for determining the 234U, 235U, 238U, 232U and 236U contents and the age of highly enriched uranium are described. Consequently, the total uranium content and isotopic composition can be calculated. For determining the 238U and 232U contents

Cong Tam Nguyen; József Zsigrai

2006-01-01

136

Basic characterization of highly enriched uranium by gamma spectrometry  

Microsoft Academic Search

Gamma-spectrometric methods suitable for the characterization of highly enriched uranium samples encountered in illicit trafficking of nuclear materials are presented. In particular, procedures for determining the 234U, 235U, 238U, 232U and 236U contents and the age of highly enriched uranium are described. Consequently, the total uranium content and isotopic composition can be calculated. For determining the 238U and 232U contents

Cong Tam Nguyen; Jozsef Zsigrai

2005-01-01

137

Monitoring of Martian atmosphere with gamma-ray spectrometry  

NASA Astrophysics Data System (ADS)

Mars Odyssey has been monitoring the leakage gamma-rays from Mars since 2002 [1]. The spectrum of these gamma-rays is made of a dominating continuum plus lines (only 4% of the count rates) [2]. The latter have been used to build compositional maps of the surface [3]; the former can be analyzed to monitor atmospheric variations with time and place [4, 5]. Sometimes both aspects can be combined when during polar winters it is possible to track the argon in the atmosphere through its discrete gamma-ray line [6]. The Martian atmosphere is quite transparent (free mean path of about 100km) at these energies (100 keV - 10 MeV), and consequently the continuum varies by only a few percents over the Martian year. However the statistics are good enough to see these variations. Previous studies revealed short and long term time variations, as well as regional differences. In particular we noticed earlier that the atmospheric cycle looks slightly different from one year to the other. Deep basins (Argyre and Hellas) seem also to act as reservoirs at some seasons. We will present an update of the study of the gamma-ray continuum, including the latest data available, in terms of transparency of the Martian atmosphere. [1] Boynton et al. (2004) Space Sci. Rev., 110 (1), 37-83; [2] Evans et al. (2006) J. Geophys. Res., accepted; [3] Boynton et al. (2006) J. Geophys. Res., in preparation; [4] Gasnault et al. (2003) LPSC 34, abstract #1649 CD-ROM; [5] Gasnault et al. (2005) 1st Mars Express Sci. Conf., Noordwijk, Netherlands; [6] Sprague et al. (2006) J. Geophys. Res., accepted.

Gasnault, O.; D'Uston, C.; Forni, O.; Maurice, S.

138

Differentiation and classification of user-specified bacterial groups by in situ thermal hydrolysis and methylation of whole bacterial cells with tert-butyl bromide chemical ionization ion trap mass spectrometry  

Microsoft Academic Search

Fatty acid methyl esters (FAMEs) from 20 bacterial samples, formed through in situ thermal hydrolysis and methylation (THM) of lipids from whole bacterial cells using tetramethylammonium hydroxide, have been investigated by t-butyl bromide chemical ionization (CI) ion trap mass spectrometry (MS). The mass spectra, in the early portion of the total ion profile, contained as major peaks the protonated saturated

Ming Xu; Franco Basile; Kent J Voorhees

2000-01-01

139

Monitoring radioactive plumes by airborne gamma-ray spectrometry  

SciTech Connect

Airborne gamma-ray spectrometer surveys using large volume sodium-iodide detectors are routinely flown throughout the world for mineral exploration and geological mapping. Techniques have now been developed to detect and map man-made sources of radiation. In Canada, airborne gamma-rays surveys have been flown around nuclear reactors to map {sup 41}Ar plumes from nuclear reactors and to calculate the dose rate at ground level. In May 1986, the Finnish Geological survey aircraft flew through a radioactive plume from the Chernobyl nuclear accident. As the aircraft flew through the plume, the aircraft became increasingly contaminated. By measuring the final aircraft contamination, the activity of the plume could be separated from the contamination due to the aircraft. Within 1 h of encountering the plume, the aircraft activity was comparable to the maximum levels found in the plume. From an analysis of the gamma-ray spectra, the concentration of {sup 131}I and {sup 140}La within the plume were calculated as a function of time.

Grasty, R.L. [Exploranium, Mississauga, Ontario (Canada); Hovgaard, J. [Danish Emergency Management Agency, Birkerod (Germany); Multala, J. [Geological Survey of Finland, Espoo (Finland)

1996-06-01

140

In situ neutron diffraction study of the low cycle fatigue of the alpha-gamma duplex stainless steel  

Microsoft Academic Search

In duplex stainless steels, significant thermal stresses are generated during the cooling from the homogenization temperature due to different thermal expansion coefficients of the austenitic and ferritic phases. The results of the in situ neutron diffraction examination of the evolution of the internal stresses during the low cycle fatigue in the SAF 2507 duplex stainless steel are reported. Stress response

Peter Jencus; Jaroslav Polák; Petr Lukás; Ondrej Muránsky

2006-01-01

141

Natural Radiation from Soil using Gamma-Ray Spectrometry  

SciTech Connect

We have studied the distribution of natural radioactivity in the soil of Interlagos, in Sao Paulo city and Billings Reservoir, in Sao Bernardo do Campo, Sao Paulo, Brazil. The main contribution of the effective radiation dose is due to the elements of the {sup 238}Th decay series, with smaller contributions from {sup 40}K and the elements of the series of {sup 238}U. The results indicate the dose in all of the studied areas is around the average international dose due to external exposure to gamma rays (0.48 mSv/yr) proceeding from natural terrestrial elements.

Silveira, M. A. G.; Moreira, R. H.; Paula, A. L. C. de [Centro Universitario da FEI, Sao Bernardo do Campo, Sao Paulo (Brazil); Medina, N. H. [Instituto de Fisica da Universidade de Sao Paulo, Sao Paulo (Brazil)

2009-06-03

142

Natural gamma-ray spectrometry as a tool for radiation dose and radon hazard modelling.  

PubMed

We reviewed the calibration procedures of gamma-ray spectrometry with particular emphasis to factors that affect accuracy, detection limits and background radiation in field measurements for dosimetric and radon potential mapping. Gamma-ray spectra were acquired in western Liguria (Italy). The energy windows investigated are centred on the photopeaks of (214)Bi (1.76 MeV), (208)Tl (2.62 MeV) and (40)K (1.46 MeV). The inferred absorbed dose rate and the radon flux are estimated to be lower than 60 nGy h(-1) and 22 Bq m(-2)h(-1), respectively. PMID:19249218

Verdoya, M; Chiozzi, P; De Felice, P; Pasquale, V; Bochiolo, M; Genovesi, I

2009-01-24

143

Gamma ray spectrometry of LDEF samples at SRL  

NASA Astrophysics Data System (ADS)

A total of 31 samples from the Long Duration Exposure Facility (LDEF), including materials of aluminum, vanadium, and steel trunnions were analyzed by ultra-low-level gamma spectroscopy. The study quantified particle induced activations of Na-22, Sc-46, Cr-51, Mn-54, Co-56, Co-57, Co-58, and Co-60. The samples of trunnion sections exhibited increasing activity toward the outer end of the trunnion and decreasing activity toward its radial center. The trunnion sections did not include end pieces, which have been reported to collect noticeable Be-7 on their leading surfaces. No significant Be-7 was detected in the samples analyzed. The Underground Counting Facility at Savannah River Laboratory (SRL) was used in this work. The facility is 50 ft. underground, constructed with low-background shielding materials, and operated as a clean room. The most sensitive analyses were performed with a 90 percent efficient HPGe gamma-ray detector, which is enclosed in a purged active/passive shield. Each sample was counted for one to six days in two orientations to yield more representative average activities for the sample. The non-standard geometries of the LDEF samples prompted the development of a novel calibration method, whereby the efficiency about the samples surfaces (measured with point sources) predicted the efficiency for the bulk sample.

Winn, W. G.

1991-07-01

144

Determination of plutonium mass using gamma-ray spectrometry  

NASA Astrophysics Data System (ADS)

Plutonium sources with well-known isotopic ratios are routinely used in the calibration and testing of radioactive waste assay systems. The laboratories that supply these isotopic standards often do not quantify the plutonium mass. Knowledge of total plutonium mass in the sources is important for verifying the performance of passive neutron counters. The independent determination of total plutonium mass by gamma-ray techniques is rendered difficult by the lack of adequate information regarding the sample matrix and containment of the sources. Therefore, a technique that did not require knowledge of the sample matrix or containment was used to determine the plutonium masses. The technique was based on empirically extrapolating the apparent mass as a function of photon energy to conditions approximating zero photon attenuation. It was tested using measurements performed with three certified reference materials supplied by the New Brunswick Laboratory (NBL). Results were compared to those obtained from a high-efficiency neutron counter calibrated using 252Cf. The weighted average of the ratio of gamma ray to HENC plutonium masses was determined to be 0.942+/-0.029.

Venkataraman, Ramkumar; Croft, Stephen

2003-06-01

145

Development of isotope dilution gamma-ray spectrometry for plutonium analysis  

SciTech Connect

We are studying the feasibility of determining the plutonium concentration and isotopic distribution of highly radioactive, spent-fuel dissolver solutions by employing high-resolution gamma-ray spectrometry. The study involves gamma-ray plutonium isotopic analysis for both dissolver and spiked dissolver solution samples, after plutonium is eluted through an ion-exchange column and absorbed in a small resin bead bag. The spike is well characterized, dry plutonium containing {approximately}98% of {sup 239}Pu. By using measured isotopic information, the concentration of elemental plutonium in the dissolver solution can be determined. Both the plutonium concentration and the isotopic composition of the dissolver solution obtained from this study agree well with values obtained by traditional isotope dilution mass spectrometry (IDMS). Because it is rapid, easy to operate and maintain, and costs less, this new technique could be an alternative method to IDMS for input accountability and verification measurements in reprocessing plants. 7 refs., 4 figs., 4 tabs.

Li, T.K.; Parker, J.L. (Los Alamos National Lab., NM (United States)); Kuno, Y.; Sato, S.; Kurosawa, A.; Akiyama, T. (Power Reactor and Nuclear Fuel Development Corp., Tokai, Ibaraki (Japan))

1991-01-01

146

Low-level gamma-ray spectrometry for analysing fusion plasma conditions  

NASA Astrophysics Data System (ADS)

A new method, combining activation by neutrons and charged particles with ultra low-level gamma-ray spectrometry, aimed at obtaining a better understanding and more adequate measurements of MeV particle leaks in magnetic fusion devices was studied here. A total of 36 samples containing Ti, LiF, B4C and W were placed in a boron-nitride holder mounted on the ceiling of the JET Tokamak. The samples were activated by 63 pulses from a D 3He plasma and were later measured using underground gamma-ray spectrometry. The radionuclides 7Be, 46Sc, 54Mn, 56Co, 57Co, 58Co, 124Sb, 181Hf, 182Ta, 181W and 185W were detected in several of the samples, with very low levels of activity of 47Sc and 48V found in a few of the samples. The various production channels for the radionuclides in question are discussed.

Wieslander, J. S. Elisabeth; Hult, Mikael; Bonheure, Georges; Arnold, Dirk; Dombrowski, Harald; Gasparro, Joël; Laubenstein, Matthias; Marissens, Gerd; Vermaercke, Peter

2008-06-01

147

Reactions of butadiene in zeolite catalysts by in situ variable-temperature solid-state nuclear magnetic resonance spectrometry  

SciTech Connect

The mechanisms by which butadiene oligomerizes in acidic zeolite catalysts leading to deactivation by pore blockage have been elucidated by using in situ {sup 13}C solid-state NMR spectroscopy with magic-angle spinning (MAS). Butadiene is found to oligomerize primarily by the 1,4-addition reaction upon adsorption at its melting point (164 K). Secondary reactions of the oligomers are strongly dependent upon the properties of the zeolite. The initially formed linear product undergoes cyclization reactions to form fused rings in zeolite HY, but isolated rings are formed in the smaller channels of zeolite HZSM-5. Branching reactions and/or 1,2 enchainment result in an appreciable methyl group content in the oligomers formed in zeolite HY. These results provide insight into the mechanisms by which oxide catalysts are deactivated by pore blockage. Neither carbenium ions nor any other reactive intermediates were observed spectroscopically, presumably because such intermediates reacted with either free butadiene or the oligomers so rapidly as to preclude a detectable steady state concentration.

Richardson, B.R.; Lazo, N.D.; Schettler, P.D.; White, J.L.; Haw, J.F. (Texas A and M Univ., College Station (USA))

1990-04-11

148

Formation of {gamma}-Fe{sub 2}O{sub 3} nanoparticles and vacancy ordering: An in situ X-ray powder diffraction study  

SciTech Connect

The formation of maghemite, {gamma}-Fe{sub 2}O{sub 3} nanoparticles has been studied by in situ X-ray powder diffraction. The maghemite was formed by thermal decomposition of an amorphous precursor compound made by reacting lauric acid, CH{sub 3}(CH{sub 2}){sub 10}COOH with Fe(NO{sub 3}){sub 3}.9H{sub 2}O. It has been shown that cubic {gamma}-Fe{sub 2}O{sub 3} was formed directly from the amorphous precursor and that vacancy ordering starts about 45 min later at 305 deg. C resulting in a tripled unit cell along the c-axis. The kinetics of grain growth was found to obey a power law with growth exponents n equal to 0.136(6) and 0.103(5) at 305 and 340 deg. C, respectively. Particles with average sizes of 12 and 13 nm were obtained in 86 and 76 min at 305 and 340 deg. C, respectively. The structure of cubic and vacancy ordered phases of {gamma}-Fe{sub 2}O{sub 3} was studied at 305 deg. C by Rietveld refinements. - Graphical abstract: Stack of powder diagrams showing the formation of {gamma}-Fe{sub 2}O{sub 3} nanoparticles and subsequent vacancy ordering at 305 deg. C.

Jorgensen, Jens-Erik [Chemistry Department, University of Aarhus, DK-8000 Arhus C (Denmark)], E-mail: jenserik@chem.au.dk; Mosegaard, Lene [Chemistry Department, University of Aarhus, DK-8000 Arhus C (Denmark); Thomsen, Line E. [Chemistry Department, University of Aarhus, DK-8000 Arhus C (Denmark); Jensen, Torben R. [Chemistry Department, University of Aarhus, DK-8000 Arhus C (Denmark); Hanson, Jonathan C. [Chemistry Department, Brookhaven National Laboratory, Upton, NY 11973 (United States)

2007-01-15

149

In-situ X-ray diffraction measurements of the [gamma-epsilon] transition boundary of iron in an internally-heated diamond anvil cell  

SciTech Connect

The phase transition boundary between the {gamma} (face-centered cubic structure) and {epsilon} (hexagonal close-packed structure) iron phases was determined up to 69 GPa by using a newly developed internally-heated diamond anvil cell, combined with in-situ synchrotron X-ray diffraction measurements. The improved experimental configuration provides stable heating with reliable temperature and pressure determination and phase identification. A simultaneous laser- and internal-heating system was also used to produce further higher temperature at higher pressures. The sample pressure at any given temperature was calculated using an established thermal equation of state for {epsilon} iron. The {gamma}-{epsilon} transition boundary was bracketed with the normal and reversal directions and it is linear from 21 to 69 GPa with a dP/dT slope of 0.0394 GPa/K. There is no evidence for the existence of additional iron solid phase other than the {gamma} and {epsilon} phases over the P-T range of this study. We inferred that the {gamma}-{epsilon}-liquid triple point of iron should occur at 88 GPa and 2800 K.

Komabayashi, T.; Fei, Y.; Meng, Y.; Prakapenka, V.; (CIW); (UC)

2009-05-07

150

An intercomparison of Monte Carlo codes used in gamma-ray spectrometry  

Microsoft Academic Search

In an intercomparison exercise, the Monte Carlo codes most commonly used in gamma-ray spectrometry today were compared with each other in order to gauge the differences between them in terms of typical applications. No reference was made to experimental data; instead, the aim was to confront the codes with each other, as they were applied to the calculation of full-energy-peak

T. Vidmar; I. Aubineau-Laniece; M. J. Anagnostakis; D. Arnold; R. Brettner-Messler; D. Budjas; M. Capogni; M. S. Dias; L. E. De Geer; A. Fazio; J. Gasparro; M. Hult; S. Hurtado; M. Jurado Vargas; M. Laubenstein; K. B. Lee; Y. K. Lee; M. C. Lepy; F. J. Maringer; V. Medina Peyres; M. Mille; M. Moralles; S. Nour; R. Plenteda; M. P. Rubio Montero; O. Sima; C. Tomei; G. Vidmar

2008-01-01

151

The potential of gamma-ray spectrometry as supplementary information for mapping central European soils  

NASA Astrophysics Data System (ADS)

Permanently updated soil maps are needed inter alia for the prediction of landslide hazards, flooding and drought effects, land degradation monitoring, and precision farming. Since comprehensive and intensive field mapping is not affordable, alternative mapping approaches are required. A promising tool, with quite unrecognised potential for modern soil science is gamma-ray spectrometry. As the radioelements potassium, thorium and uranium respond differently to soil forming processes, it should be possible to infer from their concentration on weathering status, and after calibration on soil properties and types. This paper aims to investigate the potential of airborne gamma spectrometry for mapping of central European soils and soil properties. The study was conducted for a test site in Southern Saxony, Germany, 140*85 km wide, representing diverse soil landscapes. Seven different petrographic training and validation areas were chosen each. To assess the potential of gamma-ray spectrometry as additional data layer, predictions were carried out (i) with and (ii) without radiometric data. The outputs were compared with independent soil information of the validation areas. Both prediction runs used the following predictors: elevation, slope, curvature, planform curvature, profile curvature, terrain ruggedness index, relative altitude, vertical distance above drainage network, wetness index, and convergence index. As additional predictor parent material derived from a reclassification of the official geological map (1:1M scale) was used. As radiometric properties potassium, thorium and uranium were used. The radiometric raster datasets were generated by universal kriging using relative altitude as covariate. Training and validation datasets were selected from a comprehensive dataset representing more than 14.000 point data. Point data include soil types and substrates, and for more than 800 sites soil profiles with analysed texture, pH, exchangeable cations, nutrients, and efficient cation exchange capacity. The study shows that gamma spectrometry is suitable to enhance the prediction of soil types and properties such as texture significantly.

Schuler, U.; Bock, M.; Baritz, R.; Willer, J.; Pickert, E.; Kardel, K.; Herrmann, L.

2012-04-01

152

Measurement of plutonium and uranium isotopic abundances by gamma-ray spectrometry  

SciTech Connect

The isotopic composition of plutonium and uranium is needed for purposes of sample confirmation, or for interpreting results from calorimeters or neutron-coincidence measurement instruments to determine nuclear material mass. The authors have developed measurement methods and computer codes utilizing high-resolution gamma-ray spectrometry to measure the relative isotopic abundances of plutonium and uranium in various forms nondestructively. The computer codes, known as MGA and MGAU, have unique analysis methodologies that the authors briefly describe in this paper.

Ruhter, W.D. [Lawrence Livermore National Lab., CA (United States); Gunnink, R. [Gunnink (Ray), Fremont, CA (United States)

1996-02-01

153

Natural radioactivity traces in South-Brazilian cereal flours by gamma-ray spectrometry  

Microsoft Academic Search

Summary  Cereal flours are the major component of the Brazilian diet and are also important exportation products. Radioactivity concentrations\\u000a of 232 Th, 226Ra, 40K and 137Cs were determined in commercial samples of South-Brazilian cereal flours (soy, wheat, corn, manioc, rye and oat flour) to\\u000a verify the radiological security of these foodstuffs. The measurements were carried out by gamma-ray spectrometry using a

V. Scheibel; C. R. Appoloni; H. Schechter

2006-01-01

154

On the invariability of the total-to-peak ratio in gamma-ray spectrometry  

Microsoft Academic Search

It is demonstrated that the assumption on the independence of the total-to-peak ratio of the source position in gamma-ray spectrometry holds for coaxial detectors with sufficient accuracy to make it applicable to the determination of the full energy peak efficiencies in environmental measurements via the so-called efficiency transfer method. The calculations show that for planar detectors the assumption breaks down

Tim Vidmar; Andrej Likar

2004-01-01

155

Low-level gamma-ray spectrometry using Ge-detectors  

Microsoft Academic Search

The technological advances that have taken place during the past 45 years in the fabrication of high purity germanium crystals have had a significant impact on low-level gamma-ray spectrometry. Today, Ge-detectors with high purity Ge-crystals of 2 kg are readily available and detectors with crystals up to 5 kg can be produced. Use of large area crystals results in high

Mikael Hult

2007-01-01

156

The determination of minor elements in steel by proton-induced prompt gamma-ray spectrometry  

Microsoft Academic Search

Pure elemental targets of Si, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, Mo and W were irradiated with protons from 3.5 to 6.0 MeV,\\u000a interference-free sensitivities were calculated for analysis by prompt gamma-ray spectrometry and sensitivity curves were\\u000a plotted to show the variation of sensitivity with bombarding energy. Appropriate bombarding energies were selected for analysis\\u000a and the extent

M. Peisach; D. Gihwala

1981-01-01

157

Calculation of “LS-curves” for coincidence summing corrections in gamma ray spectrometry  

Microsoft Academic Search

When coincidence summing correction factors for extended samples are calculated in gamma-ray spectrometry from full-energy-peak and total efficiencies, their variation over the sample volume needs to be considered. In other words, the correction factors cannot be computed as if the sample were a point source. A method developed by Blaauw and Gelsema takes the variation of the efficiencies over the

Tim Vidmar; Matjaz Korun

2006-01-01

158

Low-level gamma-ray spectrometry for analysing fusion plasma conditions  

Microsoft Academic Search

A new method, combining activation by neutrons and charged particles with ultra low-level gamma-ray spectrometry, aimed at obtaining a better understanding and more adequate measurements of MeV particle leaks in magnetic fusion devices was studied here. A total of 36 samples containing Ti, LiF, B4C and W were placed in a boron-nitride holder mounted on the ceiling of the JET

J. S. Elisabeth Wieslander; Mikael Hult; Georges Bonheure; Dirk Arnold; Harald Dombrowski; Joël Gasparro; Matthias Laubenstein; Gerd Marissens; Peter Vermaercke

2008-01-01

159

Determination of metals in alloys by neutron capture gamma-ray spectrometry  

Microsoft Academic Search

A collimated neutron beam capable of providing a thermal neutron flux of 4.75·107 n·cm?2·sec?1 has been used to analyze alloy samples of 1–5 g during relatively short irradiation times of 30 min by the use of neutron\\u000a capture gamma-ray spectrometry. The analyses were performed by using a mathematical treatment that relates the count ratio\\u000a of every constituent present in the

M. Heurtebise; J. A. Lubkowitz

1976-01-01

160

Artificial neural network modelling of uncertainty in gamma-ray spectrometry  

Microsoft Academic Search

An artificial neural network (ANN) model for the prediction of measuring uncertainties in gamma-ray spectrometry was developed and optimized. A three-layer feed-forward ANN with back-propagation learning algorithm was used to model uncertainties of measurement of activity levels of eight radionuclides (226Ra, 238U, 235U, 40K, 232Th, 134Cs, 137Cs and 7Be) in soil samples as a function of measurement time. It was

S. Dragovic; A. Onjia; S. Stankovic; I. Ani?in; G. Bacic

2005-01-01

161

An analysis of the potassium concentrations of soft drinks by HPGe gamma spectrometry  

Microsoft Academic Search

Potassium, in a variety of compounds, occurs in abundance in the Earth’s crust, and is an essential nutrient for human health.\\u000a A naturally occurring radioactive isotope of potassium, 40K, is found in the food and water that we consume. This paper presents the results of a gamma spectrometry analysis of the\\u000a 40K concentrations of a selection of commercial soft drinks.

Guillermo Espinosa; Ilsa Hernández-Ibinarriaga; Jose-Ignacio Golzarri

2009-01-01

162

Gamma Ray Spectrometry of Well Cores for Identification of Lithologies of Pacific Margin Basins of India  

Microsoft Academic Search

Natural Gamma Ray Spectrometry for determining the radioactive concentrations of potassium (40K), uranium (238U), and thorium (232Th) of well cores from the exploratory wells of Pacific margin basins were carried out in the laboratory. The measurements\\u000a were performed using a HP-Ge detector and an electronic setup coupled to a PC-based data acquisition and analysis system.\\u000a Data analyses of 68 samples

Hima Bindu Pitta; A. S. Nageswara Rao

2011-01-01

163

An axially symmetric gamma-ray backscatter system for DuMond spectrometry  

Microsoft Academic Search

An axially symmetric spectrometer is described which evolved from a program of measuring Compton profiles with unusually high geometric efficiency. When fitted with a large-volume Ge detector for combined X-ray and gamma-ray spectrometry, such as the 51 mm diameter LO-AX detector from EG&G, it allows Compton profiles to be measured at counting rates in excess of 20000 cps. The axially

Innes K. MacKenzie

1990-01-01

164

Pulsed Bremsstrahlung Interrogation with Photoneutron - Gamma-Ray Spectrometry for Nondestructive Evaluation  

NASA Astrophysics Data System (ADS)

A novel photoneutron-based nondestructive evaluation (NDE) technique which does not require a radioactive neutron source is presented. Some unique features of this technique include: 1) pulsed interrogation neutron production within, or very near, an inspected object, 2) spectrum tailoring of the source neutrons, and 3) compatibility with many existing high-energy, commercial x-ray inspection devices. Basic concept feasibility was first established by numerical methods. The pulsed photoneutron inspection technique performs nondestructive elemental analysis using gamma-ray spectrometry. Highly penetrating bremsstrahlung photons are produced by a pulsed electron accelerator capable of producing up to 16-MeV electrons. The photoneutrons are generated by the bremsstrahlung photons interacting with an inspected object and near-by beryllium metal. The interactions of the neutrons within an inspected item result in the emission of elemental characteristic gamma-rays. Spectrometry is performed by analyzing the gamma -rays acquired between accelerator pulses. A unique fast detection and acquisition system, using two 5.08 x 5.08 -cm organic scintillators, acquires gamma-ray emissions within 100 ns of each accelerator pulse. The fast system is capable of processing individual gamma-ray signals at count rates up to 40 MHz between accelerator pulses with a repetition rate up to 1 kHz. The system incorporates a unique x-ray flash recovery method which allows individual gamma-ray detection as soon as 75 ns after the start of each x-ray flash occurring within the detector. Conventional detection and data acquisition systems are used to acquire gamma-ray spectra for the time period between 1000 ns and the next accelerator pulse. Operational tests using a 30-ps pulse width, electron accelerator demonstrated the x-ray flash recovery methodology, gamma-ray detection, and data acquisition. Although, gamma -ray spectrometry performance was limited by x-ray flash -induced gain shifts in the photomultiplier tubes, the basic NDE concept was successfully demonstrated using a modified high-purity germanium detection system.

Jones, James Litton

165

A technique coupling the analyte electrodeposition followed by in-situ stripping with electrothermal atomic absorption spectrometry for analysis of samples with high NaCl contents  

NASA Astrophysics Data System (ADS)

A technique coupling the analyte electrodeposition followed by in-situ stripping with electrothermal atomic absorption spectrometry has been developed for determination of lead and cadmium in samples with high salt contents. To separate the analyte from the sample matrix, the analyte was in-situ quantitatively electrodeposited on a platinum sampling capillary serving as the cathode (sample volume, 20 ?L). The spent electrolyte containing the sample matrix was then withdrawn, the capillary with the analyte deposited was washed with deionized water and the analyte was stripped into a chemically simple electrolyte (5 g/L NH4H2PO4) by reversing the polarity of the electrodeposition circuit. Electrothermal atomization using a suitable optimized temperature program followed. A fully automated manifold was designed for this coupled technique and the appropriate control software was developed. The operating conditions for determination of Pb and Cd in samples with high contents of inorganic salts were optimized, the determination was characterized by principal analytical parameters and its applicability was verified on analyses of urine reference samples. The absolute limits of detection for lead and cadmium (3? criterion) in a sample containing 30 g/L NaCl were 8.5 pg and 2.3 pg, respectively (peak absorbance) and the RSD values amounted to 1.6% and 1.9% for lead (at the 40 ng mL- 1 level) and cadmium (at the 4.0 ng mL- 1 level), respectively. These values (and also the measuring sensitivity) are superior to the results attained in conventional electrothermal atomic absorption spectrometric determination of Pb and Cd in pure solutions (5 g/L NH4H2PO4). The sensitivity of the Pb and Cd determination is not affected by the NaCl concentration up to a value of 100 g/L, demonstrating an efficient matrix removal during the electrodeposition step.

?ánský, Zden?k; Rychlovský, Petr; Petrová, Zuzana; Matousek, J. P.

2007-03-01

166

Low-background gamma spectrometry for environmental radioactivity.  

PubMed

Development and performance of a low-background gamma-ray spectrometer are described. The spectrometer consists of a 131% efficient Ge detector in U-type configuration. The passive shielding consists of ultrapure lead of 6" thickness. A top muon guard is used as an active shielding. The spectrometer and shielding are positioned inside a steel room made of 6"-thick pre-World War II iron. The steel room is located underground with 33 m of water-equivalent overburden. The total integrated background rate in the energy range 50-2,700 keV was measured at 0.068 counts per second per 100 cm3 Ge volume. The spectrometer serves as a reference instrument for low-level and highly accurate environmental radioactivity measurements. One specific application of 228Ra determination in drinking water is described. With a 1 l water sample, 1-step chemical procedure, and 1,000 min counting time, a detection limit Ld = 20 mBq/l (0.55 pCi/l) was reached, which meets the EPA mandated limit of 1 pCi/l. Methods of upgrading the spectrometer as well as the predicted improvements in 228Ra detection, including direct counting of water without chemical processing, are discussed. PMID:12150281

Semkow, T M; Parekh, P P; Schwenker, C D; Khan, A J; Bari, A; Colaresi, J F; Tench, O K; David, G; Guryn, W

2002-08-01

167

Application of membrane inlet mass spectrometry for online and in situ analysis of methane in aquatic environments.  

PubMed

A method is presented for the online measurement of methane in aquatic environments by application of membrane inlet mass spectrometry (MIMS). For this purpose, the underwater mass spectrometer Inspectr200-200 was applied. A simple and reliable volumetric calibration technique, based on the mixing of two end member concentrations, was used for the analysis of CH(4) by MIMS. To minimize interferences caused by the high water vapor content, permeating through the membrane inlet system into the vacuum section of the mass spectrometer, a cool-trap was designed. With the application of the cool-trap, the detection limit was lowered from 100 to 16 nmol/L CH(4). This allows for measurements of methane concentrations in surface and bottom waters of coastal areas and lakes. Furthermore, in case of membrane rupture, the cool-trap acts as a security system, avoiding total damage of the mass spectrometer by flushing it with water. The Inspectr200-200 was applied for studies of methane and carbon dioxide concentrations in coastal areas of the Baltic Sea and Lake Constance. The low detection limit and fast response time of the MIMS allowed a detailed investigation of methane concentrations in the vicinity of gas seepages. PMID:18789719

Schlüter, Michael; Gentz, Torben

2008-08-07

168

Oxidative electrolyte solvent degradation in lithium-ion batteries. An in situ differential electrochemical mass spectrometry investigation  

SciTech Connect

Differential electrochemical mass spectrometry (DEMS) was used to study the electrochemical decomposition of organic carbonate electrolyte solutions at practical lithium metal oxide composite electrodes used in lithium-ion batteries. For propylene carbonate (PC), CO{sub 2} evolution was detected at LiNiO{sub 2}, LiCoO{sub 2}, and LiMn{sub 2}O{sub 4} composite electrodes. The starting point of gas evolution was 4.2 V vs. Li/Li{sup +} at LiNiO{sub 2}, whereas at LiCoO{sub 2} and LiMn{sub 2}O{sub 4}, CO{sub 2} evolution was observed only above 4.8 V vs. Li/Li{sup +}. In addition, various other volatile electrolyte decomposition products of PC were detected when using LiCoO{sub 2}, LiMn{sub 2}O{sub 4}, and carbon black electrodes. In ethylene carbonate/dimethylcarbonate, CO{sub 2} evolution was detected only at LiNiO{sub 2} electrodes, again starting at about 4.2 V vs. Li/Li{sup +}.

Imhof, R.; Novak, P. [Paul Scherrer Inst., Villigen PSI (Switzerland). Electrochemistry Section

1999-05-01

169

Development of a method for in situ measurement of denitrification in aquifers using 15N tracer tests and membrane inlet mass spectrometry  

NASA Astrophysics Data System (ADS)

In NO3- contaminated aquifers containing reduced compounds like organic carbon or sulfides, denitrification is an intense process. Its characterization is of interest because NO3- consump-tion improves water quality and N2O production can cause emission of this greenhouse gas to the atmosphere. Spatial distribution of NO3- and N2 produced by denitrification in groundwa-ter (excess N2) reflects the NO3- input as well as cumulative denitrification during aquifer pas-sage. Reaction progress (RP) at a given location, i.e. the relative consumption by denitrifica-tion of the NO3- that had been leached to the aquifers, characterizes the stage of the denitrifi-cation process. RP can be derived from the ratio between accumulated gaseous denitrification products and initial NO3- concentrations. The amount and spatial distribution of reduced com-pounds within denitrifying aquifers is not well known. Recent findings from parallel investi-gations on in situ denitrification and reactive compounds suggests that single-well 15N tracer tests might be suitable to characterize the stock of reduced compounds in aquifers (Konrad 2007). The overall objective of our studies is measure the spatial dynamics of denitrification within two sandy aquifers in northern Germany. This includes measurement of the actually occurring denitrification process. Moreover we want to determine the long-term denitrification potential which is governed by the stock of reactive material. Here we present a new approach for in situ-measurement of denitrification at monitoring wells using a combination of 15N-tracer push-pull experiments with in situ analysis of 15N-labled N2 and N2O using membrane inlet mass spectrometry (MIMS). We will present first results from a laboratory test with aquifer mesocosms using the MIMS method. In this test we supplemented aquifer material of two depths (2 and 7 m below surface) of a drinking water catchment in Northwest Germany with K15NO3 solution. After tracer application we took wa-ter samples at regular intervals with an automated sampling device over 5 days. A small part of the sample was directly conducted in the membrane inlet of our mass spectrometer and the other part was collected in serum bottles which were immediately sealed with rubber septa and stored for later measurement by isotope ratio mass spectrometer (IRMS). Results available up to now showed for both types of measurement a linear increase of deni-trification products (15(N2O+N2)) over time. At the end of our laboratory test we measured up to 270 and 2400 µg/L 15(N2O+N2) in the water samples from the supplemented aquifer mate-rial of 3 and 7 m depth respectively. Because of the online measurement with MIMS we were able to see during the experiment if and when the production of the labeled denitrification products started. Later-on this approach will be used in the field. Here, the MIMS-technique will be especially advantageous, because the success of tracer test can be immediately seen during in situ sampling. Results of excess-N2 measurements at the monitoring wells within the two aquifers showed a range of 0 to 30 mg L-1 excess-N2 and a RP between 0 and 100%. References: Konrad, C. (2007): Methoden zur Bestimmung des Umsatzes von Stickstoff, dargestellt für drei Pleistozäne Grundwasserleiter Norddeutschlands, PhD thesis, Dresden Univ. of Techn., Germany, 157 pp.

Eschenbach, W.; Well, R.; Flessa, H.; Walther, W.; Duijnisveld, W. H. M.

2009-04-01

170

Speciation Gamma-Spectrometry: the Fate of Environmental Radio-Nuclides in Hard-Water Lakes  

NASA Astrophysics Data System (ADS)

A sequential fractionation method for simultaneous and absolute measurement of environmental radio-nuclides, 241Am, 210Pb, 226Ra, 137Cs, 40K and 234Th/238U, by gamma-spectrometry was tested and applied to hard-water lake-sediments. The carbonate, fulvic, humic and mineral insoluble fractions were extracted from the sediments. Correction of self-absorption and geometrical effects, arising from the conditioning of bulk and fractionated sediments, were done using Monte Carlo simulations. This "non-destructive" fractionation procedure allows further analysis of other chemical species in the same fractions thus creating possibilities to study the dynamics of self-cleaning mechanism in lakes. The results demonstrate that the procedure is quantitative and suitable for the determination of environmental key radio-tracers in different fractions. Unlike other fresh-water sediments the major part of the environmental radio-nuclides is associated with "mineral" fractions. This speciation gamma-spectrometry procedure was supplemented by isotope-dilution alpha-spectrometry 210Po (210Pb), for determining the acid-soluble organic fractions in fresh-water lakes. The overall speciation procedure demonstrated that carbonate fractions, extracted from hard-water lake sediments, could be separated either free from, or associated with, fulvic-compounds. This speciation procedure can be applied to other aquatic deposits, however supplementary steps can be added if other data are required.

El-Daoushy, F.; Liger, E.; Hernández, F.; Casper, P.

2005-01-01

171

Crystalline characterization by Rutherford backscattering spectrometry and electron channelling of in situ grown YBa2Cu3O7 thin films deposited on (100) MgO by d.c. sputtering or laser ablation  

Microsoft Academic Search

YBa2Cu3O7 (YBCO) superconducting thin films have been grown in situ on single-crystal (100) MgO substrates by single target d.c. sputtering or laser ablation. The films were highly textured, with full c-axis orientation, as shown by standard Theta-2Theta X-ray diffractometry. The inplane structure of the films was characterized by reflection high energy electron diffraction (RHEED), oscillating single-crystal photographs, Rutherford backscattering spectrometry

M. Kechouane; H. L'Haridon; M. Salvi; P. N. Favennec; M. Gauneau; M. Guilloux-Viry; M. G. Karkut; C. Thivet; A. Perrin

1993-01-01

172

Determination of degradation products of chemical warfare agents in water using hollow fibre-protected liquid-phase microextraction with in-situ derivatisation followed by gas chromatography–mass spectrometry  

Microsoft Academic Search

Hollow fibre-protected liquid-phase microextraction (HF-LPME) together with gas chromatography\\/mass spectrometry was investigated for the analysis of degradation products of chemical warfare agents in water samples. The degradation products studied were those of nerve and blister agents, and a psychotomimetic agent. Extractions were successfully performed coupled with in-situ derivatisation using a mixture of solvent and derivatising agent. The protection of the

Hoi Sim Nancy Lee; Mui Tiang Sng; Chanbasha Basheer; Hian Kee Lee

2007-01-01

173

Measurement of gamma radiation levels in soil samples from Thanjavur using gamma-ray spectrometry and estimation of population exposure.  

PubMed

This study assesses the level of terrestrial gamma radiation and associated dose rates from the naturally occurring radionuclides (232)Th, (238)U and (40)K in 10 soil samples collected from Thanjavur (Tamil Nadu, India) using gamma-ray spectrometry. The activity profile of radionuclides has clearly showed the existence of low level activity in Thanjavur. The geometric mean activity concentrations of (232)Th, (238)U and (40)K is 42.9+/-9.4 Bq.kg(-1), 14.7+/-1.7 Bq.kg(-1) and 149.5+/-3.1 Bq.kg(-1) respectively are derived from all the soil samples studied. The activity concentration of (232)Th, (238)U and (40)K in soil is due to the presence of metamorphic rocks like shale, hornblende-biotite gneiss and quartzofeldspathic gneiss in these areas. Gamma absorbed dose rates in air outdoors were calculated to be in the range between 32 nGy.h(-1) and 59.1 nGy.h(-1) with an arithmetic mean of 43.3 +/-9 nGy.h(-1). This value is lesser than the population weighted world-averaged of 60 nGy.h(-1). Inhabitants of Thanjavur are subjected to external gamma radiation exposure (effective dose) ranging between 39.2 and 72.6 muSv.y(-1) with an arithmetic mean of 53.1+/-11 muSv.y(-1). The values of the external hazard index determined from the soil radioactivity of the study area are less than the recommended safe levels. PMID:20177570

Senthilkumar, B; Dhavamani, V; Ramkumar, S; Philominathan, P

2010-01-01

174

Measuring the radium quartet (228Ra, 226Ra, 224Ra, 223Ra) in seawater samples using gamma spectrometry.  

PubMed

Radium isotopes are widely used in marine studies (eg. to trace water masses, to quantify mixing processes or to study submarine groundwater discharge). While 228Ra and 226Ra are usually measured using gamma spectrometry, short-lived Ra isotopes (224Ra and 223Ra) are usually measured using a Radium Delayed Coincidence Counter (RaDeCC). Here we show that the four radium isotopes can be analyzed using gamma spectrometry. We report 226Ra, 228Ra, 224Ra, 223Ra activities measured using low-background gamma spectrometry in standard samples, in water samples collected in the vicinity of our laboratory (La Palme and Vaccarès lagoons, France) but also in seawater samples collected in the plume of the Amazon river, off French Guyana (AMANDES project). The 223Ra and 224Ra activities determined in these samples using gamma spectrometry were compared to the activities determined using RaDeCC. Activities determined using the two techniques are in good agreement. Uncertainties associated with the 224Ra activities are similar for the two techniques. RaDeCC is more sensitive for the detection of low 223Ra activities. Gamma spectrometry thus constitutes an alternate method for the determination of short-lived Ra isotopes. PMID:20106569

van Beek, P; Souhaut, M; Reyss, J-L

2010-01-27

175

Coincidence-summing corrections for extended sources in gamma-ray spectrometry using Monte Carlo simulation  

NASA Astrophysics Data System (ADS)

A new approach for the correction of summing effects in gamma-ray spectrometry with volume sources is proposed. Using a Monte Carlo code and a formalism to describe the decay schemes, the apparent full-energy-peak efficiency (which would be obtained by neglecting the summing effects) is calculated at the same time as the true one; the ratio of these two values is the correction factor. It is demonstrated that, by means of simulation, efficiencies can be evaluated with a suitable accuracy.

Décombaz, Marc; Gostely, Jean-Jacques; Laedermann, Jean-Pascal

1992-02-01

176

Measurements of activation induced by environmental neutrons using ultra low-level gamma-ray spectrometry.  

PubMed

The flux of environmental neutrons is being studied by activation of metal discs of selected elements. Near the earth's surface the total neutron flux is in the order of 10(-2) cm(-2)s(-1), which gives induced activities of a few mBq in the discs. Initial results from this technique, involving activation at ground level for several materials (W, Au, Ta, In, Re, Sm, Dy and Mn) and ultra low-level gamma-ray spectrometry in an underground laboratory located at 500 m.w.e., are presented. Diffusion of environmental neutrons in water is also measured by activation of gold at different depths. PMID:10724430

Martínez Canet, M J; Hult, M; Köhler, M; Johnston, P N

2000-03-01

177

Low-level gamma spectrometry using beta coincidence and Compton suppression  

Microsoft Academic Search

A low-level gamma-ray spectrometry system was developed using a Ge(Li) detector with 6% relative efficiency coupled to a 2? beta plastic detector for coincidence selection and a massive NaI(Tl) detector for Compton suppression.The integral background count rate for (50–1500)keV was 0.5s?1kg?1 (Ge), using only beta coincidences. With Compton suppression, a value of 0.25s?1kg?1 (Ge) was obtained. Spectra with and without

E. L Grigorescu; P. De Felice; Anamaria-Cristina Razdolescu; A Luca

2004-01-01

178

Low Background Gamma-Ray Spectrometry in the 'Laboratoire Souterrain de Modane'  

SciTech Connect

Most of the underground experiments in physics and many studies in geology, biology or environmental sciences face a common requirement with the necessity of using experimental devices with ultra-low background radioactivity. Many developments involving many different techniques have been used in order to be able to measure extremely low levels of radioactivity in materials. This report will focus on low background gamma-ray spectrometry and will describe the work which has been carried out over the last fifteen years in the 'Laboratoire Souterrain de Modane' (LSM)

Hubert, Ph.; Hubert, F. [Centre d'Etudes Nucleaires de Bordeaux Gradignan, BP 120, Le Haut Vigneau, 33175 Gradignan Cedex (France)

2007-03-28

179

In-situ gamma-ray site characterization of the Tatum Salt Dome Test Site in Lamar County, Mississippi  

Microsoft Academic Search

Field surveys of gamma-ray emitting nuclides and soil core sampling were conducted at 12 sites on the Tatum Salt Dome Test Site and surrounding control areas to determine exposure rates from surficial radioactivity. 137Cs was the only man-made radionuclide detected and was most abundant at three off-site locations on cultivated lawns. 137Cs inventories at all of the on-site survey locations

S. H. Faller

1992-01-01

180

Coincidence summing corrections for the natural decay series in gamma-ray spectrometry.  

PubMed

Using a Monte Carlo code and a Markov formalism to describe the decay schemes, coincidence-summing correction factors can be calculated with a suitable accuracy. For two different measuring geometries and an HPGe detector, calculated and experimental correction factors have been shown to closely agree for 152Eu. The simulation method has subsequently been applied in assessing the need for coincidence-summing corrections for members of the uranium, thorium and actinium series measurable by gamma-spectrometry. Correction factors were calculated for predominant gamma emissions significantly affected by coincidence-summing effects and the correctness of our calculations tested for environmental samples. The test makes it evident that in order to obtain reliable and unbiased activity values for some natural radionuclides coincidence summing cannot be neglected in environmental measurements at small source-detector distances. PMID:11258526

García-Talaver, M; Laedermann, J P; Décombaz, M; Daza, M J; Quintana, B

2001-05-01

181

Determination of ethylphenols in wine by in situ derivatisation and headspace solid-phase microextraction-gas chromatography-mass spectrometry.  

PubMed

Contamination by Brettanomyces is a frequent problem in many wineries that has a dramatic effect on wine aroma and hence its quality. The yeast Brettanomyces/Dekkera is involved in the formation of three important volatile ethylphenols-4-ethylphenol, 4-ethylguaiacol and 4-ethylcatechol-that transmit an unpleasant aroma to wine that has often been described as 'medicinal', 'stable' or 'leather'. This study proposes an in situ derivatisation and headspace solid-phase microextraction- gas chromatography coupled to mass spectrometry method to determine the three ethylphenols in red Brettanomyces-tainted wines. The most important variables involved in the derivatisation (acetic anhydride and base concentration) and the extraction (extraction temperature and salt addition) processes were optimised by experimental design. The optimal conditions using 4 mL of wine in 20-mL sealed vials were 35 muL of acetic anhydride per millilitre of wine, 1 mL of 5.5% potassium carbonate solution and 0.9 g of sodium chloride and the extraction was performed with a divinylbenzene-carboxen-poly(dimethylsiloxane) fibre at 70 degrees C for 70 min. Then, the performance characteristics were established using wine samples spiked with the ethylphenols. For all compounds, the detection limits were below the odour threshold reported in the literature and they were between 2 and 17 microg L(-1) for 4-ethylguaiacol and 4-ethylphenol, respectively. Intermediate precision (as relative standard deviation) was acceptable, with values ranging from 0.3 to 12.1%. Finally, the method was applied in the analysis of aged Brettanomyces-tainted wines. PMID:17225107

Carrillo, José David; Tena, María Teresa

2007-01-16

182

Biogenic VOC Emissions Measured by Solid Phase Microextraction (SPME) Fibers, Proton Transfer Reaction Mass Spectrometry (PTR-MS), and In-situ Gas Chromatography (GC)  

NASA Astrophysics Data System (ADS)

Chemical ozone loss due to reactions with biogenic VOCs has been shown to dominate ozone flux measured at Blodgett Forest, a coniferous forest in the Sierra Nevada Mountains of California. Here we report recent efforts to measure the specific biogenic VOCs involved in this chemistry at Blodgett Forest. During summer 2005, we enclosed branches of Ponderosa pine, manzanita, and ceanothus species and made VOC emission measurements by proton transfer reaction mass spectrometry (PTR-MS), solid phase microextraction (SPME) on fibers followed by direct injection into a gas chromatograph with an ion trap mass spectrometer (GC-ITMS), and by in-situ GC with a flame ionization detector (GC-FID). Zero air, with ambient CO2 concentrations, flowed through a 2-chamber system. The chamber placed directly over the branch had a 20 second residence time, and was immediately followed by a reaction chamber with a 2 minute residence time. The PTR-MS and GC-FID measurement cycled between each of the two chambers and the zero air supply. SPME fibers (65 ?m PDMS/DVB field portable) were used to sample the branch chamber. Several sesquiterpene, monoterpene, and oxygenated primary emissions were identified. The SPME fibers were particularly useful for detecting sesquiterpenes which are typically difficult to measure due to their high reactivity in the forest canopy and losses in sampling lines. Comparisons of SPME fiber data with PTR-MS and GC-FID data for sesquiterpenes (m/z 205), 4-allylanisole (m/z 149), and monoterpenes (m/z 137) will be presented to assess the actual emission rates and the complimentary information provided by each measurement approach.

Bouvier-Brown, N. C.; Holzinger, R.; Palitzsch, K.; Goldstein, A. H.

2005-12-01

183

In-situ gamma-ray site characterization of the Tatum Salt Dome Test Site in Lamar County, Mississippi  

SciTech Connect

Field surveys of gamma-ray emitting nuclides and soil core sampling were conducted at 12 sites on the Tatum Salt Dome Test Site and surrounding control areas to determine exposure rates from surficial radioactivity. 137Cs was the only man-made radionuclide detected and was most abundant at three off-site locations on cultivated lawns. 137Cs inventories at all of the on-site survey locations were lower than expected, given the high annual precipitation in the area. The vertical distributions were more extended than those reported for undisturbed sites. Pressurized ion chamber measurements indicated no significant differences in exposure rates on and off the test site.

Faller, S.H. (Environmental Protection Agency, Las Vegas, NV (United States))

1992-06-01

184

In-situ gamma-ray site characterization of the Tatum Salt Dome Test Site in Lamar County, Mississippi.  

PubMed

Field surveys of gamma-ray emitting nuclides and soil core sampling were conducted at 12 sites on the Tatum Salt Dome Test Site and surrounding control areas to determine exposure rates from surficial radioactivity. 137Cs was the only man-made radionuclide detected and was most abundant at three off-site locations on cultivated lawns. 137Cs inventories at all of the on-site survey locations were lower than expected, given the high annual precipitation in the area. The vertical distributions were more extended than those reported for undisturbed sites. Pressurized ion chamber measurements indicated no significant differences in exposure rates on and off the test site. PMID:1628991

Faller, S H

1992-06-01

185

New constraints on methane fluxes and rates of anaerobic methane oxidation in a Gulf of Mexico brine pool via in situ mass spectrometry  

Microsoft Academic Search

Deep-sea biogeochemical cycles are, in general, poorly understood owing to the difficulties of making measurements in situ, recovering samples with minimal perturbation, and, in many cases, coping with high spatial and temporal heterogeneity. In particular, biogeochemical fluxes of volatiles such as methane remain largely unconstrained because of the difficulties with accurate quantification in situ and the patchiness of point sources

Scott D. Wankel; Samantha B. Joye; Vladimir A. Samarkin; Sunita R. Shah; Gernot Friederich; John Melas-Kyriazi; Peter R. Girguis

2010-01-01

186

Quantitative In situ uranium contaminant mapping using high-resolution gamma-ray spectrometry and beta scintillation counting.  

National Technical Information Service (NTIS)

Traditional means of measuring radionuclide concentrations in soils over large areas are often time-consuming, cumbersome, expensive, and non-representative. In developing new methods for the real-time characterization of large-scale uranium contamination...

A. J. Schilk R. W. Perkins K. H. Abel R. L. Brodzinski D. P. Brown

1993-01-01

187

Mars vs. the Moon: The gamma-ray and neutron spectrometry perspective  

NASA Astrophysics Data System (ADS)

The contrast in composition is fainter on Mars than on the Moon, making it hard to trace back to regional provinces on Mars, while three distinctive terranes were identified on the Moon. Distributions of bulk chemical elements at the surface are crucial clues to infer the history of the planet; they help in determining the level of fractionation, the existence of reservoirs, and the evolution that lead to the present state of its surface. There are some evidences that the early differentiation of Mars was different from the Moon, in particular in terms of resulting surface materials being more uniform. The Martian crust is also intensely marked by volcanism activity at larger scales than on the Moon. In this context it is advantageous to combine the distributions of various chemical elements to delineate the places showing coherent trends. Gamma-ray spectrometry and neutron spectrometry are now part of the standard set of remote observations of terrestrial planets. We propose to review the latest results from Lunar Prospector for the Moon and from Mars Odyssey for Mars in the perspective of geochemical province definitions. One objective would be to use similar analysis tools (such as a principal component analysis) to emphasize similarities and differences between the Moon and Mars. Lunar Prospector gamma-ray spectra were analyzed to construct maps of Th and Fe, and these data are currently reprocessed to possibly obtain maps of K, Si, Al, Mg, Ti, O, U, H, and Ca. We already have shown that the first two elements (Th and Fe) are very good indicators of the three major Lunar terranes through a covariance analysis. Maps of Fe, Th, K, H, Cl, and Si distributions at the surface of Mars were derived from a recent reprocessing of Mars Odyssey gamma-ray data including appropriate corrections, normalization, and spatial distribution. In the past we combined these datasets with neutron observations to define four large provinces that show distinctive geochemical signatures.

Gasnault, O.; Mars Odyssey; Lunar Prospector GRS Teams

188

Low-level gamma spectrometry for pollution assessment in San Simón Bay (Vigo, Spain)  

NASA Astrophysics Data System (ADS)

A gamma spectrometer with HPGe detector of 50% relative efficiency and 1 cps total background has been dedicated to the measurement of an intertidal sediment core from a coastal environment at the Ría de Vigo (Spain). The area is affected by lead pollution and the source identification needs of a precise dating of the sediment core. Such a precise dating requires the measurement not only of the radionuclides directly involved in time calculation, as 210Pb and 226Ra, but also of ancillary radionuclides which inform about the dating model to apply and about the validity of its time estimation. Gamma spectrometry with Ge detectors performs a simultaneous measurement of the full content in ?-emitters of the sample. However, its use is limited by its high spectral background. We present the characteristics of our lowlevel background gamma spectrometer and also of Galea, the computing tool for the expert analysis of natural radionuclides. Both make possible to get the proper experimental results to reach a suitable dating. The results allowed us to detect a change in the sedimentation dynamics in the area under study, to verify the impact of lead pollution in the 210Pb level, to obtain a sedimentation rate by using the CF:CS model with a suitable correction factor and, finally, to validate the sediment dating.

Quintana, B.; Álvarez-Iglesias, P.; Santamaría, R.; Rubio, B.; Pérez-Arlucea, M.

2006-05-01

189

Report of the Department of Energy, Office of Environmental Management, Gamma Spectrometry Data Validation Program  

SciTech Connect

This report represents the results of analyses received on or before August 15, 1996 for the first annual Gamma Spectrometry Data Validation Program (May 1996) designed to assess the capability of DOE laboratories and DOE contractors in performing routine gamma spectra analyses. Data reduction of gamma spectra are normally performed with computer codes supplied by commercial manufacturers or are developed in house. Earlier evaluations of commercial codes gave spurious results for complex spectrum. A calibration spectrum, a background spectrum and three sample spectra of increasing complexity were included for each format. The calibration spectrum contained nuclides covering the energy range from 59.5 keV to 1836 keV. The first two samples contained fallout nuclides with halflives of over 30 days. Naturally occurring nuclides were also present. The third sample contained both short and long lived fission product nuclides. The participants were asked to report values and uncertainties as Becquerel per sample with no decay correction. Sixteen software packages were evaluated. In general, the results do not appear to be dependent on the software used. Based on the control limits established for the Program for the three sample spectra, 62%, 63% and 53%, respectively, of the reported results were evaluated as acceptable.

Decker, K.; Sanderson, C.G.; Greenlaw, P.

1996-11-01

190

International Workshop on Gamma Spectrometry Analysis Codes for U and Pu Isotopics: Workshop Results and Next Steps  

Microsoft Academic Search

In November 2008, the Institute of Nuclear Materials Management (INMM) and the European Safeguards Research and Development Association (ESARDA) co-hosted the International Workshop on Gamma Spectrometry Analysis Codes for U and Pu Isotopics at the Oak Ridge National Laboratory (ORNL). This workshop was conducted in response to needs expressed by the international safeguards community to understand better the capabilities and

Brent R McGinnis; Alexander A Solodov; Jacqueline L Shipwash; Alena V Zhernosek; Teressa L McKinney; Chris A Pickett; Paolo Peerani

2009-01-01

191

Radon fixation for determination of 224Ra, 226Ra and 228Ra via gamma-ray spectrometry  

Microsoft Academic Search

The aim of this work is the improvement of the procedure for the determination of radium isotopes activities in water, which is done through radiochemical separation and subsequent gamma-ray spectrometry. In addition, radon gas retention is studied using different activated carbon materials. The results of the IAEA Proficiency test: “Determination of radium and uranium radionuclides in water” of December 2002

M. Herranz; R. Idoeta; A. Abelairas; F. Legarda

2006-01-01

192

Assessment of on-line burnup monitoring of pebble bed reactor fuel using passive gamma-ray spectrometry  

Microsoft Academic Search

An investigation was performed to assess the feasibility of passive gamma-ray spectrometry assay as an approach for on-line burnup determination for the Modular Pebble Bed Reactor (MPBR). In addition to its inherently safe design, a unique feature of this reactor is its multipass fuel cycle in which graphite fuel pebbles are randomly loaded and continuously circulated through the core until

Ayman I. Hawari; Jianwei Chen; Bingjing Su; Zhongxiang Zhao

2002-01-01

193

Monte Carlo calculations of coincidence-summing corrections for volume sources in gamma-ray spectrometry with Ge detectors  

Microsoft Academic Search

A Monte Carlo simulation approach to solve the problem of measuring volume sources in gamma-ray spectrometry is described. The simulation package PENELOPE, with a cylindrical geometry tool was used to model two measurement systems and to calculate the detection efficiency for volume sources of ? emitters affected by coincidence-summing effects. ?-Ray spectra and experimental detection efficiencies from multi-? emitting nuclides

Eduardo García-Toraño; Milagros Pozuelo; Francesc Salvat

2005-01-01

194

On the determination of 226 Ra in soils and uranium ores by direct gamma-ray spectrometry  

Microsoft Academic Search

The evaluation of the source term in facilities related to the first stages of nuclear fuel involves the determination of radium concentration, as well as those from other radionuclides members of the uranium series. These activities are often required within a short time period, making impossible the use of radiochemical methods or the gamma-ray spectrometry of radium daughters. In those

A. Martinez Lobo; J. Palomares

1991-01-01

195

Calculation of “LS-curves” for coincidence summing corrections in gamma ray spectrometry  

NASA Astrophysics Data System (ADS)

When coincidence summing correction factors for extended samples are calculated in gamma-ray spectrometry from full-energy-peak and total efficiencies, their variation over the sample volume needs to be considered. In other words, the correction factors cannot be computed as if the sample were a point source. A method developed by Blaauw and Gelsema takes the variation of the efficiencies over the sample volume into account. It introduces the so-called LS-curve in the calibration procedure and only requires the preparation of a single standard for each sample geometry. We propose to replace the standard preparation by calculation and we show that the LS-curves resulting from our method yield coincidence summing correction factors that are consistent with the LS values obtained from experimental data.

Vidmar, Tim; Korun, Matjaž

2006-01-01

196

Summary of gamma spectrometry on local air samples from 1985--1995  

SciTech Connect

This report summarizes the 1985--1995 results of low-level HPGe gamma spectrometry analysis of high-volume air samples collected at the Aiken Airport, which is about 25 miles north of SRS. The author began analyzing these samples with new calibrations using the newly developed GRABGAM code in 1985. The air sample collections were terminated in 1995, as the facilities at the Aiken Airport were no longer available. Air sample measurements prior to 1985 were conducted with a different analysis system (and by others prior to 1984), and the data were not readily available. The report serves to closeout this phase of local NTS air sample studies, while documenting the capabilities and accomplishments. Hopefully, the information will guide other applications for this technology, both locally and elsewhere.

Winn, W.G.

1997-04-02

197

The Sandwich spectrometer for ultra low-level gamma-ray spectrometry.  

PubMed

The technical details and performance of the newly developed Sandwich spectrometer for ultra low-level gamma-ray spectrometry are presented. The spectrometer, which consists of two HPGe detectors, an active muon shield and a lead/copper shield with a convenient and rapid opening mechanism, is located in an underground laboratory at a depth of 500 m water equivalent. The data is collected in list mode, which enables off-line data analysis to identify muon-induced events and possible Ge detector crosstalk due to Compton scattering. The background count-rate from 40 to 2700 keV normalised to the mass of the Ge crystals is 220 day(-1)kg(-1). PMID:19246202

Wieslander, J S Elisabeth; Hult, Mikael; Gasparro, Joël; Marissens, Gerd; Misiaszek, Marcin; Preusse, Werner

2009-01-23

198

Low-level gamma spectrometry using beta coincidence and Compton suppression.  

PubMed

A low-level gamma-ray spectrometry system was developed using a Ge(Li) detector with 6% relative efficiency coupled to a 2pi beta plastic detector for coincidence selection and a massive NaI(Tl) detector for Compton suppression. The integral background count rate for (50-1500)keV was 0.5 s(-1)kg(-1) (Ge), using only beta coincidences. With Compton suppression, a value of 0.25 s(-1)kg(-1) (Ge) was obtained. Spectra with and without Compton suppression were studied for 60Co, 137Cs and 152Eu point sources. Considerations are made concerning the Compton suppression advantages in different situations. PMID:15177343

Grigorescu, E L; De Felice, P; Razdolescu, Anamaria-Cristina; Luca, A

199

Initial recommendations for restricting gamma-ray spectrometry measurements of radionuclides for on-site inspections  

Microsoft Academic Search

The US paper �Radionuclide Sampling, Sample Handling and Analytical Laboratory Equipment for Comprehensive Test Ban Treaty On-Site Inspections,� CTBT\\/PC\\/V\\/OSI\\/WSII\\/PR\\/29 identified the radionuclides of interest to an OS1 as 144<\\/sup>Ce, 147<\\/sup>Nd, 141<\\/sup>Ce, 149<\\/sup>Ba140<\\/sup>La), 95<\\/sup> Zr(95<\\/sup>Nb), 131m<\\/sup>Xe, 133m<\\/sup>Xe, 133g<\\/sup>Xe, 135g<\\/sup>Xe, and 37<\\/sup>Ar. All of these nuclides (except 37<\\/sup>Ar) can be measured via some form of conventional or coincidence-based gamma-ray spectrometry. The non-gaseous

W. F. Buckley; S. A. Kreek; J. F. Wild

1998-01-01

200

Investigation of the soil-plant transfer of primordial radionuclides in tomatoes by low-level gamma-ray spectrometry.  

PubMed

The paper presents actual data from investigations of the soil-plant transfer of the primordial radionuclides 40K, 238U, 226Ra, 210Pb and 227Ac for tomatoes growing at soils from former uranium mining areas. The analysis were carried out using low-level gamma-ray spectrometry in a 47 m deep underground laboratory. For tomato fruits transfer factors of (0.0007 +/- 0.0006) for 235U, (0.0021 +/- 0.0017) for 226Ra, (0.0015 +/- 0.0009) for 210Pb and (0.0018 +/- 0.0012) for 227Ac were obtained. The investigation of the soil-plant transfer by low-level gamma-ray spectrometry is often limited by the Compton-continuum from the always present high-energy gamma-ray emitter 40K. PMID:10879862

Köhler, M; Gleisberg, B; Niese, S

201

High Throughput In Situ XAFS Screening of Catalysts  

SciTech Connect

We outline and demonstrate the feasibility of high-throughput (HT) in situ XAFS for synchrotron radiation studies. An XAS data acquisition and control system for the analysis of dynamic materials libraries under control of temperature and gaseous environments has been developed. The system is compatible with the 96-well industry standard and coupled to multi-stream quadrupole mass spectrometry (QMS) analysis of reactor effluents. An automated analytical workflow generates data quickly compared to traditional individual spectrum acquisition and analyses them in quasi-real time using an HT data analysis tool based on IFFEFIT. The system was used for the automated characterization of a library of 91 catalyst precursors containing ternary combinations of Cu, Pt, and Au on {gamma}-Al2O3, and for the in situ characterization of Au catalysts supported on Al2O3 and TiO2.

Tsapatsaris, Nikolaos; Beesley, Angela M.; Weiher, Norbert; Tatton, Helen; Schroeder, Sven L. M. [The University of Manchester, Molecular Materials Centre, School of Chemical Engineering and Analytical Science, Manchester, M60 1QD, PO Box 88 (United Kingdom); School of Chemistry, Manchester, M60 1QD, PO Box 88 (United Kingdom); Dent, Andy J.; Mosselmans, Frederick J. W. [Diamond Light Source, Chilton, Didcot, OX12 0QX (United Kingdom); Tromp, Moniek; Russu, Sergio [University of Southampton, School of Chemistry, Southampton, SO17 1BJ, (United Kingdom); Evans, John [Diamond Light Source, Chilton, Didcot, OX12 0QX (United Kingdom); University of Southampton, School of Chemistry, Southampton, SO17 1BJ, (United Kingdom); Harvey, Ian; Hayama, Shu [CCRLC Daresbury Laboratory, Warrington, Cheshire, WA4 4AD (United Kingdom)

2007-02-02

202

Monte Carlo calculations of coincidence-summing corrections for volume sources in gamma-ray spectrometry with Ge detectors  

NASA Astrophysics Data System (ADS)

A Monte Carlo simulation approach to solve the problem of measuring volume sources in gamma-ray spectrometry is described. The simulation package PENELOPE, with a cylindrical geometry tool was used to model two measurement systems and to calculate the detection efficiency for volume sources of ? emitters affected by coincidence-summing effects. ?-Ray spectra and experimental detection efficiencies from multi-? emitting nuclides as 60Co, 88Y, 134Cs, 152Eu and 166mHo are compared to the simulation results.

García-Toraño, Eduardo; Pozuelo, Milagros; Salvat, Francesc

2005-06-01

203

Measuring the radium quartet ( 228Ra, 226Ra, 224Ra, 223Ra) in seawater samples using gamma spectrometry  

Microsoft Academic Search

Radium isotopes are widely used in marine studies (eg. to trace water masses, to quantify mixing processes or to study submarine groundwater discharge). While 228Ra and 226Ra are usually measured using gamma spectrometry, short-lived Ra isotopes (224Ra and 223Ra) are usually measured using a Radium Delayed Coincidence Counter (RaDeCC). Here we show that the four radium isotopes can be analyzed

P. van Beek; M. Souhaut; J.-L. Reyss

2010-01-01

204

Gamma-ray spectrometry of ultra low levels of radioactivity within the material screening program for the GERDA experiment.  

PubMed

In present and future experiments in the field of rare events physics a background index of 10(-3) counts/(keV kg a) or better in the region of interest is envisaged. A thorough material screening is mandatory in order to achieve this goal. The results of a systematic study of radioactive trace impurities in selected materials using ultra low-level gamma-ray spectrometry in the framework of the GERDA experiment are reported. PMID:19243966

Budjás, D; Gangapshev, A M; Gasparro, J; Hampel, W; Heisel, M; Heusser, G; Hult, M; Klimenko, A A; Kuzminov, V V; Laubenstein, M; Maneschg, W; Simgen, H; Smolnikov, A A; Tomei, C; Vasiliev, S I

2009-01-21

205

Classification of soil samples according to their geographic origin using gamma-ray spectrometry and principal component analysis  

Microsoft Academic Search

A principal component analysis (PCA) was used for classification of soil samples from different locations in Serbia and Montenegro. Based on activities of radionuclides (226Ra, 238U, 235U, 40K, 134Cs, 137Cs, 232Th and 7Be) detected by gamma-ray spectrometry, the classification of soils according to their geographical origin was performed. Application of PCA to our experimental data resulted in satisfactory classification rate

Snežana Dragovi?; Antonije Onjia

2006-01-01

206

Non invasive measurement of fused solar salts level by gamma-ray spectrometry of potassium natural radioactivity  

Microsoft Academic Search

A feasibility test, concerning a non invasive method for measuring the level of fused solar salts in a storage vessel, is described. The method is based on the spectrometry of gamma-rays emitted by the salts performed by a scintillation detector positioned outside the vessel insulation. Measurements concerned the fused solar salts (a binary mixture of NaNO3 and KNO3, 60%m and

R. Scafè; F. Pisacane; R. Grena; F. Fabrizi; D. Mazzei; T. Crescenzi; M. Salmi

2008-01-01

207

Gamma-ray spectrometry across the Upper Devonian basin succession at Kowala in the Holy Cross Mountains (Poland)  

Microsoft Academic Search

The Upper Devonian sequence at Kowala in the Holy Cross Mountains was logged using gamma-ray spectrometry, for investigating the changes of oxygenation level in the Late Devonian basin. The Th\\/U ratio indicates that oxygen levels were low throughout the Late Frasnian interval, with low peaks during the Kellwasser Events showing anoxic conditions in the basin. The F-F boundary interval was

DAVE BOND

208

Classification of soil samples according to geographic origin using gamma-ray spectrometry and pattern recognition methods  

Microsoft Academic Search

Multivariate data analysis methods were used to recognize and classify soils of unknown geographic origin. A total of 103 soil samples were differentiated into classes, according to regions in Serbia and Montenegro from which they were collected. Their radionuclide (226Ra, 238U, 235U, 40K, 134Cs, 137Cs, 232Th and 7Be) activities detected by gamma-ray spectrometry were then used as the inputs in

Snezana Dragovic; Antonije Onjia

2007-01-01

209

Prompt-gamma spectrometry for the optimization of reactor neutron beams in biomedical research  

SciTech Connect

In order to select the optimal spectral composition and size for the reactor neutron beams applied to in vivo analysis and therapy in biomedical research it is necessary to determine the spatial slow-neutron flux distributions produced by the beam in the irradiated object and to calculate or measure the neutron dose equivalents of both the original spectrum and the moderated neutrons. In this study the maximum neutron dose equivalents are found by spectrometry of the prompt-..gamma.. emission from the interaction of neutrons with atomic nuclei in the irradiated object. Different spectral distributions were produced by using an unfiltered beam together with filters of quartz, cadmium, /sup 10/B, iron, aluminum, and sulfur. The phantom used was a tank filled with an aqueous solution of urea. Cadmium-containing organs were simulated. For in vivo neutron-activation analysis of human tissues at a depth of 2-5 cm it was found advisable to use neutrons of 20-40 keV mean energy with a beam area of at least 45 cm/sup 2/.

Borisov, G.I.; Komkov, M.M.; Leonov, V.F.

1988-06-01

210

THE GAMMA-RAY SPECTROMETRY OF FISSION PRODUCTS. V. GAMMA-RAY SPECTROMETRIC ANALYSIS OF FALLOUT SAMPLES  

Microsoft Academic Search

The gamma spectrometric method for the analysis of fission products was ; applied to some fall-out samples. They included snow, dust in the open air, and ; ashes of plants. Comparison was made between the apparent ages of samples from ; the experimental gamma -ray spectra with those from the beta decay curves of ; the same samples. The agreement

Hattori

1961-01-01

211

Gamma spectrometry of EFTTRA T2BIS R280.2. Gamma scan wires 6 through 10.  

National Technical Information Service (NTIS)

In the frame work of the EFTTRA programme on recycling of actinides and fission products, five gamma scan wires which were included in the experiment R280.2 T2bis have been examined by gamma scanning. The results of the measurements have been described in...

G. Dassel H. A. Buurveld J. C. Plakman

1996-01-01

212

Sublimation extraction coupled with gas chromatography-mass spectrometry: A new technique for future in situ analyses of purines and pyrimidines on Mars  

Microsoft Academic Search

We have developed a sublimation technique coupled with chemical derivatization and gas chromatography mass spectrometry (GC-MS) to detect nucleobases and other volatile organic compounds derived from bacteria in Mars analog materials. To demonstrate this technique, a sample of serpentine inoculated with Escherichia coli (E. coli) cells was heated to 500°C for several seconds under Martian ambient pressure. The sublimate was

D. P. Glavin; H. J. Cleaves; A. Buch; M. Schubert; A. Aubrey; J. L. Bada; P. R. Mahaffy

2006-01-01

213

Quantitative Analysis of CF4 Produced in the SiO2 Etching Process Using c-C4F8, C3F8, and C2F6 Plasmas by In Situ Mass Spectrometry  

NASA Astrophysics Data System (ADS)

The use of CF32+ as a specific product ion to selectively quantify CF4 produced in the SiO2 etching process using plasmas of perfluorocompounds (PFCs), such as c-C4F8, C3F8, and C2F6, has been proposed and investigated in the present experiments by measuring mass spectra inside and outside the plasmas. It is known that the CF32+ ion does not appear in the mass spectra of any stable PFCs, except for CF4. It is confirmed in the present experiments that the quantity of CF32+ originating from the CF3 radical in the mass spectra measured in situ is negligible. Other unstable chemical species in the plasmas are too small in quantity to explain the intensity of CF32+ appearing in the mass spectra measured in situ, even if they could produce stable CF32+ by ionization. It is therefore concluded that CF32+ can be used as a fingerprint of CF4 in mass spectrometry. Application of this new method for the quantitative analysis of CF4 produced in the SiO2 etching process using PFC plasmas results in CF4 production advancing significantly not only in the etching region of SiO2 but also in the downstream region of the plasmas.

Furuya, Kenji; Hatano, Yoshihiko

2004-01-01

214

Multi-scale monitoring of a marine geologic methane source in the Santa Barbara Channel using imaging spectrometry, ARCTAS-CARB in situ sampling and coastal hourly total hydrocarbon measurements  

NASA Astrophysics Data System (ADS)

The Coal Oil Point (COP) hydrocarbon seep field off the coast of Santa Barbara, CA is one of the most active and best-studied marine geologic methane sources in the world and contributes to elevated terrestrial methane concentrations downwind. In this study, we investigate the spatiotemporal variability of this local source and the influence of meteorological conditions on transport and concentration. A methane plume emanating from Trilogy Seep was mapped with the Airborne Visible Infrared Imaging Spectrometer at a 7.5 m resolution with a short-wave infrared band ratio technique. This structure agrees with the local wind speed and direction and is orthogonal to the surface currents. ARCTAS-CARB aircraft in situ sampling of lower-troposphere methane is compared to sub-hour total hydrocarbon concentration (THC) measurements from the Santa Barbara Air Pollution Control District (SBAPCD) station located near COP. Hourly SBAPCD THC values from 1980-2008 demonstrate a decrease in seep source strength until the late 1990s, followed by a consistent increase. The occurrence of elevated SBAPCD THC values for onshore wind conditions as well as numerous positive outliers as high as 17 ppm suggests that seep field emissions are both quasi-steady state and transient, direct (bubble) and diffuse (outgassing). As demonstrated for the COP seeps, the combination of imaging spectrometry, aircraft in situ sampling, and ground-based monitoring provides a powerful approach for understanding local methane sources and transport processes.

Bradley, E. S.; Leifer, I.; Roberts, D.; Dennison, P. E.; Margolis, J.; Moritsch, M.; Diskin, G. S.; Sachse, G. W.

2009-12-01

215

A statistical approach to the choice of channel-width in gamma-ray spectrometry using empirical relations between resolution and gamma-ray energy  

Microsoft Academic Search

The problem of extra peak-broadening caused by the finite channel-width in multichannel gamma-ray spectrometry is discussed,\\u000a using empirical equations for the relations between resolution and energy for NaI(T1) scintillation detectors and Ge(Li) drift\\u000a detectors. Relations are derived and graphs designed to estimate the extra peak-broadening at a certain energy, caused by\\u000a the compromise necessary when using a chosen energy scale

R. Furler; H. Poppe

1974-01-01

216

Accurate gamma-ray spectrometry measurements of the half-life of 92Sr.  

PubMed

Studies of the nuclear fuel cycle require an accurate knowledge of the energy release from the decay of radioactive nuclides produced in a reactor, including precise half-life data for the short-lived radionuclides. Moreover, short-lived fission products are crucial for fission rate distribution measurements performed in low-power facilities, such as EOLE and MINERVE of CEA Cadarache [Fougeras, P., 2005. EOLE, MINERVE and MASURCA facilities and their associated neutron experimental programs. In: 13th International Conference on Nuclear Engineering, Beijing, China, 16-20 May 2005], and their nuclear decay data need to be known to high precision. For these reasons, the half-life of (92)Sr has been measured to solve a recently observed inconsistency identified with the quoted value in the main nuclear applications libraries (including JEFF3.1): T(1/2)=2.71+/-0.01 h [Parsa, B., Ashari, A., Goolvard, L., Nobar, Y.M., 1971. Decay scheme of 2.71 h (92)Sr. Nucl. Phys. A 175, 629-640]. An overestimation of 4.5% has been identified in this work, based on two independent methods. Specific gamma-ray spectrometry measurements on activated fissile foils have been carried out, using two HPGe detectors. Influencing factors such as net area measurements of photopeaks, pulse pile-up accuracy and dead time corrections in the presence of decaying activity are discussed. A new value has been obtained by combining eight series of measurements: T(1/2)=2.594+/-0.006 h. The uncertainty has been reduced by a factor of two with respect to previous evaluations. This measured value also shows good agreement with the most recent studies of T(1/2)=2.627+/-0.009 h [Nir-El, Y., 2003. Private Communications. Soreq Research Centre, Yavne, Israel]. PMID:18456504

Leconte, P; Hudelot, J P; Antony, M

2008-03-13

217

Determination of Radioactivity in Multibelled Samples by Computer-Aided Automatic gamma and beta -Spectrometry.  

National Technical Information Service (NTIS)

A computer and a multichannel analyzer have been coupled to an automatic gamma -counter and a liquid scintillation counter to determine the radioactivity in multilabelled gamma and beta -emitting samples. Both quantitative and qualitative analyses can be ...

D. Mascanzoni

1980-01-01

218

Janus Probe, a Detection System for High Energy Reactor gamma-Ray Spectrometry.  

National Technical Information Service (NTIS)

In reactor environments, gamma-ray spectra are continuous and the absolute magnitude as well as the general shape of the gamma continuum are of paramount importance. Consequently, conventional methods of gamma-ray detection are not suitable for in-core ga...

R. Gold B. J. Kaiser

1980-01-01

219

Solubilized liquid scintillator for beta spectrometry and gamma dosimetry of uniformly distributed gamma sources in aqueous solutions  

Microsoft Academic Search

The detection and the spectrometry of $beta$-radiation in aqueous ; solutions by the scintillation counting technique is studied with a water ; fraction (30-100%) high enough to bar the use of the scintillators otherwise ; customarily employed. The following possibilities are investigated and ; delineated in terms of their applicabilities: 1) Cerenkov count. 2) Emulsion ; count (emulsification of a

Lahmann

1974-01-01

220

IN-SITU ASSAY OF TRANSURANIC RADIONUCLIDES IN THE VADOSE ZONE USING HIGH-RESOLUTION SPECTRAL GAMMA LOGGING - A HANFORD CASE STUDY  

SciTech Connect

High-resolution spectral gamma logging in steel-cased boreholes is used to detect and quantify transuranic radionuclides in the subsurface. Pu-239, Pu-241, Am-241, and Np-237 are identified based on characteristic decay gammas. Typical minimum detectable levels are on the order of 20 to 40 nCi/g. In intervals of high transuranic concentrations, gamma rays from other sources may complicate analysis and interpretation. Gamma rays detected in the borehole may originate from three sources: decay of the parent transuranic radionuclide or a daughter; alpha interactions; and interactions with neutrons resulting from either spontaneous fission or alpha particle interactions.

ROHAY VJ; HENWOOD P; MCCAIN R

2009-11-30

221

Angular distribution of proton leakage from a fusion plasma using ultra low-level gamma-ray spectrometry.  

PubMed

This experiment aimed at studying a technique to measure the leakage of charged particles from a fusion plasma. The activity induced in samples of various materials placed on a special holder inside a Tokamak was measured using ultra low-level gamma-ray spectrometry (ULGS) performed in three underground laboratories. In total, 27 radionuclides were detected in this experiment. Seven of these radionuclides were mainly produced by proton interactions. For two of them it was possible to determine their angular distribution. PMID:19962906

de Orduña, R González; Hult, M; Bonheure, G; Arnold, D; Dombrowski, H; Laubenstein, M; Wieslander, J S E; Vidmar, T; Vermaercke, P

2009-11-13

222

Non invasive measurement of fused solar salts level by gamma-ray spectrometry of potassium natural radioactivity  

NASA Astrophysics Data System (ADS)

A feasibility test, concerning a non invasive method for measuring the level of fused solar salts in a storage vessel, is described. The method is based on the spectrometry of gamma-rays emitted by the salts performed by a scintillation detector positioned outside the vessel insulation. Measurements concerned the fused solar salts (a binary mixture of NaNO3 and KNO3, 60%m and 40%m, respectively) contained in the Casaccia PCS experimental solar facility and working at 408oC. Preliminary results demonstrated the method's feasibility by using the information from the 1.46 MeV 40K gamma-ray line (11% branching ratio). Two deterministic models, as well as Monte Carlo simulations, were implemented for predicting the responses along the tank and specific algorithms, based on 1 or 3 detectors, were developed for the estimation of salt level.

Scafè, R.; Pisacane, F.; Grena, R.; Fabrizi, F.; Mazzei, D.; Crescenzi, T.; Salmi, M.

2008-04-01

223

S100A7 (Psoriasin), highly expressed in Ductal Carcinoma In Situ (DCIS), is regulated by IFN-gamma in mammary epithelial cells  

Microsoft Academic Search

BACKGROUND: The aim of the present work was to explore signal transduction pathways used in the regulation of S100A7 (psoriasin). Members of the S100 gene family participate in many important cellular functions. Psoriasin, S100A8 (calgranulin A) and S100A9 (calgranulin B) are expressed in ductal carcinoma in situ (DCIS), as well as in the hyperproliferative skin disease, psoriasis. In the latter

Stina Petersson; Anna Bylander; Maria Yhr; Charlotta Enerbäck

2007-01-01

224

Detection of in-situ derivatized peptides in microbial biofilms by laser desorption 7.87 eV postionizaton mass spectrometry.  

SciTech Connect

A novel analytical method based on laser desorption postionization mass spectrometry (LDPI-MS) was developed to investigate the competence and sporulation factor-a pentapeptide of amino acid sequence ERGMT-within intact Bacillus subtilis biofilms. Derivatization of the neat ERGMT peptide with quinoline- and anthracene-based tags was separately used to lower the peptide ionization potential and permit direct ionization by 7.87-eV vacuum ultraviolet radiation. The techniques of mass shifting and selective ionization of the derivatized peptide were combined here to permit detection of ERGMT peptide within intact biofilms by LDPI-MS, without any prior extraction or chromatographic separation. Finally, imaging MS specific to the derivatized peptide was demonstrated on an intact biofilm using LDPI-MS. The presence of ERGMT in the biofilms was verified by bulk extraction/LC-MS. However, MALDI imaging MS analyses were unable to detect ERGMT within intact biofilms.

Edirisinghe, P. D.; Moore, J. F.; Skinner-Nemec, K. A.; Lindberg, C.; Giometti, C. S.; Veryovkin, I. V.; Hunt, J. E.; Pellin, M. J.; Hanley, L.; Biosciences Division; Univ. of Illinois at Chicago; MassThink

2007-01-01

225

Automated Complex for Information Retrieval and Processing in the gamma-Resonance Spectrometry.  

National Technical Information Service (NTIS)

A complex for information retrieval and processing in the Moessbauer effect spectrometry is described. The complex consists of a set of 4 precision spectrometers nad a program system for the computation of Moessbauer effect spectrum. High velocity accurac...

V. N. Belogurov V. A. Bylinkin

1977-01-01

226

In situ real-time studies of oxygen incorporation in complex oxide thin films using spectroscopic ellipsometry and ion scattering and recoil spectrometry  

SciTech Connect

The surface termination of c-axis oriented YBa{sub 2}Cu{sub 3}O{sub 7{minus}{delta}} (YBCO) and the oxygen incorporation mechanism has been investigated using a unique combination of spectroscopic ellipsometry (SE) and time of flight ion scattering and recoil spectrometry (ToF-ISARS). The high surface sensitivity of the ToF-ISARS technique combined with the bulk oxygen sensitivity of SE are shown to yield complimentary information. The SE provided the film orientation and quality, while ToF-ISARS supplied surface compositional and structural information and enabled isotopic {sup 18}O tracer studies. It was determined that the O content of the film had little effect on the surface termination of the film, indicating a lack of labile Cu(1) sites at the c-axis oriented YBCO surface. Also, strong evidence for a Ba or BaO terminated structure is shown. The data related to the {sup 18}O tracer studies indicate that O from the reaction ambient incorporates only into the labile Cu(1) sites during both deposition and annealing, while stable O sites were populated with O from the sputtered target, indicating either the need for sputtered atomic O or sputtered YCuO complexes to occupy the stable Cu(2) sites.

Mueller, A. H.; Gao, Y.; Irene, E. A.; Auciello, O.; Krauss, A. R.; Achultz, J. A.

2000-05-25

227

Nondestructive and quantitative characterization of TRU and LLW mixed-waste using active and passive gamma-ray spectrometry and computed tomography  

Microsoft Academic Search

The technology being proposed by LLNL is an Active and Passive Computed Tomography (A P CT) Drum Scanner for contact-handled (CH) wastes. It combines the advantages offered by two well-developed nondestructive assay technologies: gamma-ray spectrometry and computed tomography (CT). Coupled together, these two technologies offer to nondestructively and quantitatively characterize mixed- wastes forms. Gamma-ray spectroscopy uses one or more external

D. C. Camp; H. E. Martz

1991-01-01

228

Close-geometry efficiency calibration in gamma-ray spectrometry using radio-nuclides with a two-step cascade decay  

Microsoft Academic Search

When efficiency calibration is performed in gamma-ray spectrometry with point sources in close geometry, radio-nuclides emitting photons of a single energy are usually utilized in order to avoid problems arising from true coincidence summing. Radio-nuclides emitting gamma-rays in a simple two-step cascade are therefore not considered suitable for such measurements. It is, namely, not possible to determine the full-energy-peak and

T. Vidmar; M. Korun; A. Likar

2003-01-01

229

The effect of different sample-calibrant composition in gamma-ray spectrometry for the assessment of the radiation dose rate in the luminescence dating of sediments  

Microsoft Academic Search

One of the basic steps in luminescence dating is the determination of the annual radiation dose. Among the suitable determination\\u000a methods in the case of sediment dating is HPGe gamma-ray spectrometry, primarily yielding the concentrations of K, Th and\\u000a U via measurement of gamma-rays emitted by 40K and by 232Th and 235,238U and their decay products. These determinations involve both

F. De Corte; D. Vandenberghe; S. M. Hossain; A. De Wispelaere; P. Van den Haute

2004-01-01

230

Contributions of gamma-ray spectrometry to terrestrial impact crater studies: The example of Serra da Cangalha, northeastern Brazil  

NASA Astrophysics Data System (ADS)

Several geophysical methods have been used for decades for the identification and exploration of impact craters. Most of them are based on seismic, potential fields and electrical data, focusing on exploration of anomalies caused by changes in physical properties or by structures associated with the formation of the crater. Gamma-ray spectrometry is usually not mentioned among the geophysical methods employed in crater studies, although it is known that impact cratering processes cause a number of physical/chemical changes in the country rocks. These changes include the remobilization of hydrothermal fluids which directly modify the composition of target rocks and, subsidiarily, of soils related to these rocks. Therefore, the distribution of radioactive elements K, Th and U has the potential to map such modifications. We present the analysis of gamma-ray signatures at the Serra da Cangalha impact structure, located in northeastern Brazil, using methods for enhancing K anomalies and also the overall gamma-ray signatures. These results provide valuable information on the distinct zones within the crater and might contribute to the understanding of hydrothermal enrichment processes produced as a result of the impact event.

Vasconcelos, Marcos Alberto R.; Leite, Emilson P.; Crósta, Alvaro P.

2012-02-01

231

Determination of Vanadium by Instrumental Neutron Activation Analysis in Conjunction with Compton Suppression Gamma-Ray Spectrometry  

SciTech Connect

The toxicity of vanadium has been known for a long time. It is only recently that vanadium has been recognized as an essential trace element. The determination of vanadium with high precision and accuracy in tissues, foods, and other biological materials is needed for the purpose of studying its effect on human nutrition and health. Several techniques such as spectrophotometry, atomic absorption, X-ray fluorescence, and neutron activation analysis (NAA) can be used for its determination. Vanadium can be determined by NAA through its short-lived nuclide {sup 52}V produced via the {sup 51}V(n, {gamma}){sup 52}V reaction; it has a 1434.2-keV gamma ray and a half-life of 3.74 min. It has been reported that {sup 52}V has sufficient sensitivity for its measurement down to nanogram levels. However, it is seldom assayed in practice by instrumental NAA (INAA) in conjunction with conventional gamma-ray spectrometry, in particular for low vanadium content in high-salt biological materials, due to the Compton background interference from nuclides such as {sup 28}Al, {sup 38}Cl, {sup 56}Mn, and {sup 24}Na. Alternatively, radiochemical NAA or preconcentration NAA methods are used to separate vanadium from the major and interfering elements. A Compton suppression counting technique can be beneficially used under such situations. One of the objectives of this work was to fully explore the advantages of Compton suppression counting for the determination of vanadium in biological samples.

W. H. Zhang; A. Chatt

2000-11-12

232

Determination of fluorine by the spectrometry of prompt gamma-rays  

Microsoft Academic Search

The use, for analysis, of prompt gamma-rays excited by 5 MeV alpha-particles from the reactions19F(?,???)19F,19F(?, n?)22Na and19F(?, p?)22NE, was studied. The precision of the analyses depended on the gamma-ray energy used for the measurement. Relative standard\\u000a deviations were ±1.8, ±0.9 and ±1.3% using the 110-, 197- or 1275 keV gamma-rays. The method was tested with N. I. M. standard\\u000a materials

I. S. Giles; M. Peisach

1976-01-01

233

Stir bar sorptive extraction with in situ derivatization and thermal desorption-gas chromatography-mass spectrometry for trace analysis of methylmercury and mercury(II) in water sample.  

PubMed

A method for the trace analysis of methylmercury (MeHg) and Hg(II) in water sample was developed, which involved stir bar sorptive extraction (SBSE) with in situ alkylation with sodium tetraethylborate and thermal desorption (TD)-gas chromatography-mass spectrometry (GC-MS). The limits of quantification of MeHg and Hg(II) are 20 and 10 ng L(-1) (Hg), respectively. The method shows good linearity and the correlation coefficients are higher than 0.999. The average recoveries of MeHg and Hg(II) in tap or river water sample are 102.1-104.3% (R.S.D.: 7.0-8.9%) and 105.3-106.2% (R.S.D.: 7.4-8.5%), respectively. This simple, accurate, sensitive, and selective analytical method may be used in the determination of trace amounts of MeHg and Hg(II) in tap and river water samples. PMID:19084638

Ito, Rie; Kawaguchi, Migaku; Sakui, Norihiro; Okanouchi, Noriya; Saito, Koichi; Seto, Yasuo; Nakazawa, Hiroyuki

2008-09-11

234

Hollow fiber liquid-phase microextraction with in situ derivatization combined with gas chromatography-mass spectrometry for the determination of root exudate phenylamine compounds in hot pepper ( Capsicum annuum L.).  

PubMed

Hollow fiber liquid-phase microextraction (HF-LPME) with derivatization was developed for the determination of three root exudate phenylamine compounds in hot pepper ( Capsicum annuum L.) by gas chromatography-mass spectrometry (GC-MS). The performance and applicability of the proposed procedure were evaluated through the extraction of 1-naphthylamine (1-NA), diphenylamine (DPA), and N-phenyl-2- naphthaleneamine (N-P-2-NA) in a recirculating hydroponic solution of hot pepper. Parameters affecting the extraction efficiency were investigated. The calibration curves showed a good linearity in the range of 0.1-10 ?g mL(-1). The limits of detection (S/N = 3) for the three compounds were 0.096, 0.074, and 0.057 ?g mL(-1), respectively. The enrichment factors reached 174, 196, and 230 at the concentration of 5 ?g mL(-1), and relative standard deviations (RSD) of 9.5, 8.6, and 7.8% and 8.4, 7.6, and 6.2% were obtained at concentrations of 2 and 5 ?g mL(-1) for 1-NA, DPA, and N-P-2-NA, respectively. Recoveries ranging from 90.2 to 96.1% and RSDs below 9.1% were obtained when HF-LPME with in situ derivatization was applied to determine root exudate 1-NA, DPA, and N-P-2-NA after 15 and 30 days of culture solution, respectively. PMID:23706116

Sun, Haiyan; Wang, Yan

2013-06-03

235

Magnetometry, Radiometry and gamma Spectrometry of the Janjao Diatreme, Lages, State of Santa Catarina, Brazil.  

National Technical Information Service (NTIS)

Magnetic, radiometric and gamma spectrometric surveys have been carried out on the Janjao diatreme which outcrops near Lajes in central-east Santa Catarina State, Brazil. The body is deeply weathered on the surface and its concentrates contain serpentiniz...

D. P. Svisero

1985-01-01

236

Isotopic analysis of uranium by neutron activation and high resolution gamma ray spectrometry  

Microsoft Academic Search

A method is described for the non-destructive and accurate determination of the isotopic composition of uranium by activation\\u000a analysis. The high resolving power of Ge(Li) detectors permits easy identification on a single gamma spectrum of the gamma\\u000a peaks of239Np formed from238U by activation and those of fission products formed from235U. The ratio of the peak intensities is proportional to the238U\\/235U

M. Mantel; J. Gilat; S. Amiel

1969-01-01

237

Gamma-ray spectrometry analysis of pebble bed reactor fuel using Monte Carlo simulations  

Microsoft Academic Search

Monte Carlo simulations were used to study the gamma-ray spectra of pebble bed reactor fuel at various levels of burnup. A fuel depletion calculation was performed using the ORIGEN2.1 code, which yielded the gamma-ray source term that was introduced into the input of an MCNP4C simulation. The simulation assumed the use of a 100% efficient high-purity coaxial germanium (HPGe) detector,

Jianwei Chen; Ayman I. Hawari; Zhongxiang Zhao; Bingjing Su

2003-01-01

238

Decay heat of ²³U fission products by beta- and gamma-ray spectrometry  

Microsoft Academic Search

The fast-rabbit facilities of the ORRR were used to irradiate 1- to 10-..mu..g samples of ²³U for 1, 10, and 100 s. Released power is observed using nuclear spectroscopy to permit separate observations of emitted ..beta.. and ..gamma.. spectra in successive time intervals. The spectra were integrated over energy to obtain total decay heat and the ..beta..- and ..gamma..-ray results

J. K. Dickens; T. A. Love; J. W. McConnell; R. W. Peelle

1976-01-01

239

STUDY OF THE U\\/Th RATIO IN A THORITE FROM KIVU (BELGIAN CONGO) WITH REGARD TO ITS UTILIZATION IN THE PREPARATION OF THORIUM STANDARDS FOR GAMMA SPECTROMETRY  

Microsoft Academic Search

The uranium and thorium contents of a thorite from Kivu were determined. ; The very low U\\/Th ratio found makes this mineral a good standard for gamma ; spectrometry and fer all other direct radiometric measurements of thorium. The ; mineral was used in the preparation of ThB standards for the determination of the ; absolute age of rocks and

Poulaert

1958-01-01

240

Determination of Fluorine in NBS Coal and Coal Fly Ash by Proton Induced Gamma Ray Emission and Spark Source Mass Spectrometry  

Microsoft Academic Search

Fluorine concentrations in US National Bureau of Standards standard reference materials 1632a (coal) and 1633a (coal fly ash) have been determined by proton induced gamma ray emission (PIGME) and spark source mass spectrometry (SSMS) using the method of standard additions. Good agreement was obtained between the two techniques with no significant bias. The mean values for 1632a and 1633a were

E. Clayton; L. S. Dale

1985-01-01

241

Accurate computation of coincidence summing corrections in low level gamma-ray spectrometry  

Microsoft Academic Search

The GESPECOR (Germanium Spectrometry Correction factors) software, previously developed for computing the self-attenuation and coincidence summing corrections, was applied to the computation of the coincidence summing correction factors for a well-type and two coaxial HPGe detectors. Cylindrical samples as well as Marinelli beaker samples were considered. The computed values are in good agreement with carefully measured values. A detailed study

Octavian Sima; Dirk Arnold

2000-01-01

242

A new low-level gamma-ray spectrometry system for environmental radioactivity at the underground laboratory Felsenkeller.  

PubMed

A low-level gamma-ray spectrometry system, based on an HPGe-detector with 92% relative efficiency recently installed in the underground laboratory Felsenkeller at 110 m water equivalent (w.e.) depth, is described. The integral background count rate normalised to the Ge-crystal mass in the energy range from 40 keV until 2.7 MeV of 0.034 s(-1)kg(-1) has been achieved by careful material selection of the detector construction material, a graded shielding construction and effective radon suppression. The detector is highly suitable for the effective surveillance of water for human consumption with decision thresholds for (226)Ra and (228)Ra in the order of some mBq L(-1). PMID:19246204

Köhler, M; Degering, D; Laubenstein, M; Quirin, P; Lampert, M-O; Hult, M; Arnold, D; Neumaier, S; Reyss, J-L

2009-01-23

243

[Radioactive cesium analysis in radiation-tainted beef by gamma-ray spectrometry with germanium semiconductor detector].  

PubMed

The detection limit and precision of radioactive cesium measurement in beef by gamma-ray spectrometry with a germanium semiconductor detector were evaluated. Measurement for 2,000 seconds using a U-8 container (100 mL) provided a detection limit of radioactive cesium (the sum of 134Cs and 137Cs) of around 20 Bq/kg. The 99% confidence interval of the measurement of provisional maximum residue limit level (491 Bq/kg) samples ranged from 447 to 535 Bq/kg. Beef is heterogeneous, containing muscle and complex fat layers. Depending on the sampled parts, the measurement value is variable. It was found that radioactive cesium content of the muscle layer was clearly different from that of fat, and slight differences were observed among parts of the sample (SD=16.9 Bq/kg), even though the same region (neck block) of beef sample was analyzed. PMID:23132357

Minatani, Tomiaki; Nagai, Hiroyuki; Nakamura, Masashi; Otsuka, Kimihito; Sakai, Yoshimichi

2012-01-01

244

Dose rate constant of a Cesium-131 interstitial brachytherapy seed measured by thermoluminescent dosimetry and gamma-ray spectrometry  

SciTech Connect

The aim of this work was to conduct an independent determination of the dose rate constant of the newly introduced Model CS-1 {sup 131}Cs seed. A total of eight {sup 131}Cs seeds were obtained from the seed manufacturer. The air-kerma strength of each seed was measured by the manufacturer whose calibration is traceable to the air-kerma strength standard established for the {sup 131}Cs seeds at the National Institute of Standards and Technology (1{sigma} uncertainty <1%). The dose rate constant of each seed was measured by two independent methods: One based on the actual photon energy spectrum emitted by the seed using gamma-ray spectrometry and the other based on the dose-rate measured by thermoluminescent dosimeter (TLD) in a Solid Water{sup TM} phantom. The dose rate constant in water determined by the gamma-ray spectrometry technique and by the TLD dosimetry are 1.066{+-}0.064 cGyh{sup -1}U{sup -1} and 1.058{+-}0.106 cGyh{sup -1}U{sup -1}, respectively, showing excellent agreement with each other. These values, however, are approximately 15% greater than a previously reported value of 0.915 cGyh{sup -1}U{sup -1} [Med. Phys. 31, 1529-1538 (2004)]. Although low-energy fluorescent x rays at 16.6 and 18.7 keV, originating from niobium present in the seed construction, were measured in the energy spectrum of the {sup 131}Cs seeds, their yields were not sufficient to lower the dose rate constant to the value of 0.915 cGyh{sup -1}U{sup -1}. Additional determinations of the dose rate constant may be needed to establish an AAPM recommended consensus value for routine clinical use of the {sup 131}Cs seed.

Chen, Z.; Bongiorni, P.; Nath, R. [Department of Therapeutic Radiology, Yale University School of Medicine, New Haven, Connecticut 06504 (United States)

2005-11-15

245

Attributes from NMIS Time Coincidence, Fast-Neutron Imaging, Fission Mapping, And Gamma-Ray Spectrometry Data  

SciTech Connect

This work tests a systematic procedure for analyzing data acquired by the Nuclear Materials Identification System (NMIS) at Oak Ridge National Laboratory with fast-neutron imaging and high-purity germanium (HPGe) gamma spectrometry capabilities. NMIS has been under development by the US Department of Energy Office of Nuclear Verification since the mid-1990s, and prior to that by the National Nuclear Security Administration Y-12 National Security Complex, with NMIS having been used at Y-12 for template matching to confirm inventory and receipts. In this present work, a complete set of NMIS time coincidence, fast-neutron imaging, fission mapping, and HPGe gamma-ray spectrometry data was obtained from Monte Carlo simulations for a configuration of fissile and nonfissile materials. The data were then presented for analysis to someone who had no prior knowledge of the unknown object to accurately determine the description of the object by applying the previously-mentioned procedure to the simulated data. The best approximation indicated that the unknown object was composed of concentric cylinders: a void inside highly enriched uranium (HEU) (84.7 {+-} 1.9 wt % {sup 235}U), surrounded by depleted uranium, surrounded by polyethylene. The final estimation of the unknown object had the correct materials and geometry, with error in the radius estimates of material regions varying from 1.58% at best and 4.25% at worst; error in the height estimates varied from 2% to 12%. The error in the HEU enrichment estimate was 5.9 wt % (within 2.5{sigma} of the true value). The accuracies of the determinations could be adequate for arms control applications. Future work will apply this iterative reconstructive procedure to other unknown objects to further test and refine it.

Swift, Alicia L [ORNL; Grogan, Brandon R [ORNL; Mullens, James Allen [ORNL; Hayward, J P [University of Tennessee, Knoxville (UTK); Mihalczo, John T [ORNL

2012-01-01

246

Modern aerial gamma-ray spectrometry and regional potassium map of the conterminous United States  

USGS Publications Warehouse

Aerial gamma-ray surveys of the natural environment measure the flux of gamma rays produced by the radioactive decay of 40K, 214Bi, and 208Tl in the upper 10-20 cm of surface materials. 40K is a radioactive potassium isotope which can be used to estimate the total amount of potassium in the soils and rocks. 214Bi is a decay product of the 238U radioactive decay series and is used to estimate the uranium concentrations, and 208Tl, a decay product of the 232Th radioactive decay series, is used to estimate thorium concentrations. Aerial gamma-ray data covering the 48 contiguous states of the United States have been compiled to produce maps showing the distributions of equivalent uranium, equivalent thorium, and potassium. This compilation involved processing the aerial survey data from about 470 1?? ?? 2?? quadrangle maps. ?? 1990.

Duval, J. S.

1990-01-01

247

High resolution gamma-ray spectrometry of culverts containing transuranic waste at the Savannah River Site  

SciTech Connect

A number of concrete culverts used to retrievably store drummed, dry, radioactive waste at the Savannah River Site (SRS), were suspected of containing ambiguous quantities of transuranic (TRU) nuclides. These culverts were assayed in place for Pu-239 content using thermal and fast neutron counting techniques. High resolution gamma-ray spectroscopy on 17 culverts, having neutron emission rates several times higher than expected, showed characteristic gamma-ray signatures of neutron emitters other than Pu-239 (e.g., Pu-238, Pu/Be, or Am/Be neutron sources). This study confirmed the Pu-239 content of the culverts with anomalous neutron rates and established limits on the Pu-239 mass in each of the 17 suspect culverts by in-field, non-intrusive gamma-ray measurements.

Hofstetter, K.J.; Sigg, R.

1990-12-31

248

High resolution gamma-ray spectrometry of culverts containing transuranic waste at the Savannah River Site  

SciTech Connect

A number of concrete culverts used to retrievably store drummed, dry, radioactive waste at the Savannah River Site (SRS), were suspected of containing ambiguous quantities of transuranic (TRU) nuclides. These culverts were assayed in place for Pu-239 content using thermal and fast neutron counting techniques. High resolution gamma-ray spectroscopy on 17 culverts, having neutron emission rates several times higher than expected, showed characteristic gamma-ray signatures of neutron emitters other than Pu-239 (e.g., Pu-238, Pu/Be, or Am/Be neutron sources). This study confirmed the Pu-239 content of the culverts with anomalous neutron rates and established limits on the Pu-239 mass in each of the 17 suspect culverts by in-field, non-intrusive gamma-ray measurements.

Hofstetter, K.J.; Sigg, R.

1990-01-01

249

Mathematical model of gamma-ray spectrometry borehole logging for quantitative analysis  

USGS Publications Warehouse

A technique for analyzing gamma-ray spectral-logging data has been developed, in which a digital computer is used to calculate the effects of gamma-ray attentuation in a borehole environment. The computer model allows for the calculation of the effects of lithology, porosity, density, and the thickness of a horizontal layer of uniformly distributed radioactive material surrounding a centralized probe in a cylindrical borehole. The computer program also contains parameters for the calculation of the effects of well casing, drilling fluid, probe housing, and losses through the sodium-iodide crystal. Errors associated with the commonly used mathematical assumption of a point detector are eliminated in this model. (USGS)

Schimschal, Ulrich

1981-01-01

250

Gamma spectrometry and chemical characterization of ceramic seeds with samarium-153 and holmium-166 for brachytherapy proposal.  

PubMed

Ceramic seeds were synthesized by the sol-gel technique with Si:Sm:Ca and Si:Ho:Ca. One set of seeds was irradiated in the TRIGA type nuclear reactor IPR-R1 and submitted to instrumental neutron activation analysis (INAA), K(0) method, to determine mass percentage concentration of natural samarium and holmium in the seed as well as to determine all existing radionuclides and their activities. Attention was paid to discrimination of Si-31, Ca-40, Ca-45, Ca-47, Ca-49, Sm-145, Sm-155, Sm-153 and Ho-166. A second sample was submitted to atomic emission spectrometry (ICP-AES) also to determine samarium and holmium concentrations in weight. A third sample was submitted to X-ray fluorescence spectrometry to qualitatively determine chemical composition. The measured activity was due to Sm-153 and Ho-166 with a well-characterized gamma spectrum. The X-ray fluorescence spectrum demonstrated that there is no discrepancy in seed composition. The maximum ranges in the water of beta particles from Sm-153 and Ho-166 decay were evaluated, as well as the dose rate and total dose delivered within the volume delimited by the range of the beta particles. The results are relevant for investigation of the viability of producing Sm-153 and Ho-166 radioactive seeds for use in brachytherapy. PMID:20685128

Valente, Eduardo S; Campos, Tarcísio P R

2010-07-27

251

DETERMINATION OF AIRBORNE FISSION PRODUCT RADIOACTIVITY USING GAMMA-RAY SPECTROMETRY  

Microsoft Academic Search

A method for the rapid determination of the radon and thoron daughter ; content of an air filter shortly after removal from the pump is described. It ; utilizes gamma -ray measurements in a portion of the energy spectrum in which ; the spectral shape does not change with time. Afterwards, the contribution to ; the net counting-rate over a

P. F. Gustafson; S. S. Brar; U. C. Mishra

1962-01-01

252

Elemental analysis of a comet nucleus by passive gamma ray spectrometry from a penetrator  

Microsoft Academic Search

The Comet Rendezvous Asteroid Flyby (CRAF) spacecraft, to be launched in 1991, was designed to study the physical and chemical properties of cometary and asteroid bodies. It is proposed that these properties can be determined by utilizing a penetrator experiment delivery system aboard the CRAF, which would deliver a passive gamma ray spectrometer to the comet and determine the composition

Larry G. Evans; Jacob I. Trombka; William V. Boynton

1986-01-01

253

High sensitivity gamma-ray spectrometry: state of the art and trial application of factor analysis  

Microsoft Academic Search

The remote sensing of terrestrial gamma rays has application in geologic mapping, mineral exploration, reactor site monitoring, location of lost radioactive sources, measurement of the water equivalence of snow, and soil mapping. Although the state of the art is quite good, there is a need to reexamine the use of detectors other than thallium activated sodium iodide detectors (e.g., plastic

Joseph S. Duval

1977-01-01

254

Determination of Radionuclides in Drinking Water by gamma Spectrometry: An Interlaboratory Collaborative Study.  

National Technical Information Service (NTIS)

Four reference samples, containing three or all four gamma emitters, exp 60 Co, exp 106 Ru, exp 134 Cs, and exp 137 Cs, from 6 to 400 pCi/L, were prepared and analytical results from 32 participating laboratories evaluated. Coefficients of variation for r...

V. R. Casella C. T. Bishop

1982-01-01

255

GAMMA SPECTROMETRY OF ARTIFICIAL RADIONUCLIDES COLLECTED BY FILTRATION OF THE AIR AT GROUND LEVEL  

Microsoft Academic Search

The radioisotopes in the atmosphere were filtered and the gamma activity ; was counted from March 9 to April 24, 1959, in Naples. The results showed that ; the reciprocal of the activity approximates a straight line. It was deduced that ; the artificial activity originated from a single event about 40 days before the ; collection. The energy interval

G. Aliverti; F. Demichelis; G. Lovera

1959-01-01

256

[Ductal carcinoma in situ].  

PubMed

Ductal carcinoma in situ (DCIS) is now found far more frequently because of mammograms, appearing with microcalcifications. Actually, it is probably very common. Premalignant lesions such as ductal carcinoma in situ are demonstrating the truth of a major concept: that there are lesions within the breast that may be locally removed and controlled before the development of metastatic disease. This article, presents the current management of ductal carcinoma in situ. PMID:15065365

Roisman, Isaac; Lifshitz, Isaac; Bitterman, A; Cohen, O

2004-03-01

257

Large-area proportional counter for in situ transuranic measurements  

SciTech Connect

Improved methods for site characterization are desired for environmental restoration at nuclear facilities. Measurements of transuranics, in particular several isotopes of plutonium, are especially difficult due to the low penetrating nature of the radiations involved, namely, alpha particles and X rays. The effects of attenuation by soil and vegetation generally render direct alpha survey methods useless. For this reason, thin scintillators, such as the FIDLER (field instrument for detection of low-energy radiation) or its more sophisticated successor, the VIOLINIST, that rely on the detection of the L shell X rays (13 to 21 keV) are used for survey work. Semiconductor detectors (germanium and silicon), used singly or in arrays, can be effective, especially for situations where {sup 241}Am (60 keV) is present in the isotropic mix. In principle, in situ spectrometric techniques that have been successfully applied at higher photon energies for the measurement of gamma-emitting radionuclides in the environment can be extended to the X-ray region as well. For situations where {sup 241}Am is not present or its ratio to plutonium is unknown, an alternative detector that we have explored for in situ X-ray spectrometry is a large-area proportional counter (LAPC). These instruments were developed for X-ray astronomical measurements in space and offer the combination of large window area and medium energy resolution. Smaller versions have also been used for lung counting.

Miller, K.M.

1994-12-31

258

Measurement of gamma radiation levels in soil samples from Thanjavur using ?-ray spectrometry and estimation of population exposure  

PubMed Central

This study assesses the level of terrestrial gamma radiation and associated dose rates from the naturally occurring radionuclides 232Th, 238U and 40K in 10 soil samples collected from Thanjavur (Tamil Nadu, India) using ?-ray spectrometry. The activity profile of radionuclides has clearly showed the existence of low level activity in Thanjavur. The geometric mean activity concentrations of 232Th, 238U and 40K is 42.9±9.4 Bq.kg?1, 14.7±1.7 Bq.kg?1 and 149.5±3.1 Bq.kg?1 respectively are derived from all the soil samples studied. The activity concentration of 232Th, 238U and 40K in soil is due to the presence of metamorphic rocks like shale, hornblende-biotite gneiss and quartzofeldspathic gneiss in these areas. Gamma absorbed dose rates in air outdoors were calculated to be in the range between 32 nGy.h?1 and 59.1 nGy.h?1 with an arithmetic mean of 43.3 ±9 nGy.h?1. This value is lesser than the population weighted world-averaged of 60 nGy.h?1. Inhabitants of Thanjavur are subjected to external gamma radiation exposure (effective dose) ranging between 39.2 and 72.6 ?Sv.y?1 with an arithmetic mean of 53.1±11 ?Sv.y?1. The values of the external hazard index determined from the soil radioactivity of the study area are less than the recommended safe levels.

Senthilkumar, B.; Dhavamani, V.; Ramkumar, S.; Philominathan, P.

2010-01-01

259

High Throughput In Situ EXAFS Instrumentation for the Automatic Characterization of Materials and Catalysts  

SciTech Connect

An XAS data acquisition and control system for the in situ analysis of dynamic materials libraries under control of temperature and gaseous environment has been developed. It was integrated at the SRS in Daresbury, UK, beamline 9.3, using a Si (220) monochromator and a 13 element solid state Ge fluorescence detector. The core of the system is an intelligent X, Y, Z, {theta} positioning system coupled to multi-stream quadrupole mass spectrometry analysis (QMS). The system is modular and can be adapted to other synchrotron radiation beamlines. The entire software control was implemented using Labview and allows the scan of a variety of library sizes, in several positions, angles, gas compositions and temperatures with minimal operator intervention. The system was used for the automated characterization of a library of 91 catalyst precursors containing ternary combinations of Cu, Pt, and Au on {gamma}-Al2O3, and for the evaluation and structural characterization of eight Au catalysts supported on Al2O3 and TiO2 Mass spectrometer traces reveal conversion rate oscillations in 6wt % Au/{gamma}Al2O3 catalysts. The use of HT experimentation for in situ EXAFS studies demonstrates the feasibility and potential of HT in situ XAFS for synchrotron radiation studies.

Tsapatsaris, Nikolaos; Beesley, A. M.; Weiher, Norbert; Schroeder, Sven L. M. [School of Chemical Engineering and Analytical Science, Molecular Materials Centre, University of Manchester, Sackville Street, P.O. Box 88. Manchester, M60 1QD (United Kingdom); Tromp, Moniek; Evans, John [School of Chemistry, University of Southhampton, Highfield, Southampton, SO17 1BJ (United Kingdom); Dent, A. J. [Diamond Light Source Ltd., Diamond House, Chilton, Didcot, Oxfordshire, OX11 0DE (United Kingdom); Harvey, Ian [Synchrotron Radiation Source (SRS), Daresbury Laboratory, Warrington, Cheshire, WA4 4AD (United Kingdom)

2007-01-19

260

Radiation Hard Fiber Optic Data Link for in situ gamma dot testing of TTL logic level I/O digital components and systems  

NASA Astrophysics Data System (ADS)

A radiation Hardened Fiber Optic Data Link which allows Automatic Test Equipment (ATE) to communicate with a device or system under test in a flash X-ray environment was designed, built, installed and tested. The data link uses TTL (Transistor to Transistor Logic) logic. The fiber optic data link has a Total Integrated Dose (TID) hardness greater than 250 krads and a gamma dose rate survivability greater than 1E12 rad (Si)/sec. Test data obtained by interfacing a Tektronix S-3295 with a DUT (which may be either a simple device or a full system) during gamma dose rate irradiation of 1E12 rad(Si)/sec is included. Except for the time delay the data link is transparent to the ATE. The link has a data rate greater than 60Mb/s NRZ (Non Return to Zero). AlGaAs 830nM LEDs and Si PIN diodes are used. The hardness of this link allows it to be used in a variety of applications.

Krinsky, Jeffrey A.; Majoch, Tim R.; Reynolds, Richard A.

261

Practical applicability of field gamma-ray scintillation spectrometry in geophysical surveys  

PubMed

We discuss the problems and calibration procedures for a portable gamma-ray scintillation spectrometer for determinations of potassium, uranium and thorium concentration in rocks. Particular emphasis was given to the evaluation of the background radiation. The apparatus was tested in the field at two selected areas in NW Italy. We found appropriate sites which could be used as reference targets to frequently check the gamma-ray equipment. An area formed by serpentinitic rocks showed such a low measured radioactivity that it could be used as a reference for the local background effect. An anomalously high uranium amount against negligible potassium and thorium concentrations were found in outcrops of dolomitic rocks, which can be used to detect possible changes in the instrument calibration constants. PMID:10879864

Chiozzi; Pasquale; Verdoya; De Felice P

2000-07-01

262

A deviation display method for visualising data in mobile gamma-ray spectrometry.  

PubMed

A real time visualisation method, to be used in mobile gamma-spectrometric search operations using standard detector systems is presented. The new method, called deviation display, uses a modified waterfall display to present relative changes in spectral data over energy and time. Using unshielded (137)Cs and (241)Am point sources and different natural background environments, the behaviour of the deviation displays is demonstrated and analysed for two standard detector types (NaI(Tl) and HPGe). The deviation display enhances positive significant changes while suppressing the natural background fluctuations. After an initialization time of about 10min this technique leads to a homogeneous display dominated by the background colour, where even small changes in spectral data are easy to discover. As this paper shows, the deviation display method works well for all tested gamma energies and natural background radiation levels and with both tested detector systems. PMID:20456962

Kock, Peder; Finck, Robert R; Nilsson, Jonas M C; Ostlund, Karl; Samuelsson, Christer

2010-04-24

263

On-line analysis of coal by neutron induced gamma spectrometry  

Microsoft Academic Search

Thermal neutron prompt gamma activation analysis (PGNAA) has proven to be a useful tool for the multi-elemental characterization\\u000a of coal. The use of isotopic neutron sources allows the construction of relatively small irradiation facilities for the on-line\\u000a analysis of large volume samples. As a first step to an on-line analysis system for process control in a coal blending plant\\u000a we

H. R. Wilde; W. Herzog

1982-01-01

264

Spectrometry of a 60Co Gamma-Ray Beam Used for Instrument Calibration  

Microsoft Academic Search

Measurements were made of the spectrum of one of the collimated 60Co gamma-ray beams employed in the instrument-calibration program of the National Bureau of Standards. The high-activity calibration-source capsule was replaced by one of low activity and identical geometry. The contributions to the spectrum by the scatter from the low-activity replacement source, the housing, and the collimation system were isolated

M Ehrlich; S M Seltzer; M J Bielefeld; J I Trombka

1976-01-01

265

Multielement analysis of major and minor elements by thermal neutron induced capture gamma-ray spectrometry  

Microsoft Academic Search

The utility of prompt gamma-rays from thermal neutron capture for the measurement of nine elements (Si, Al, Fe, Na, K, Ca,\\u000a Ti, Mg and P) in major and minor abundance has been investigated. National Bureau of Standards (NBS) and United States Geological\\u000a Survey (USGS) standards were used to demonstrate generally good agreement between experimental measurements and certified\\u000a values. Usually accuracies

E. S. Gladney; D. B. Curtis; E. T. Jurney

1978-01-01

266

Assessment of calibration parameters for an aerial gamma spectrometry system using Monte-Carlo technique.  

PubMed

During a radiation emergency subsequent to a nuclear accident or weapon fallout, quick assessment of the ground contamination and the resulting exposure is of prime importance in planning and execution of effective counter measures. For an online assessment of ground contamination, it is essential to calibrate the detector system for several parameters viz. the source energy, source deployment matrix, the flight altitude and position above the contaminated surface. This article discusses the methodology to predict all the necessary parameters like photon fluence at various altitudes, the photo-peak counts in different energy windows, Air to Ground Correlation Factors IAGCF) and the dose rate at any height due to air scattered gamma ray photons. The methodology includes generation of theoretically simulated gamma spectra at a required detector position for a given source distribution on the ground using Monte-Carlo method provided by general purpose coupled neutron/photon transport code (MCNP CCC-200). Thus generated gamma spectra are analyzed to arrive at the required parameters mentioned above. PMID:15900666

Srinivasan, P; Raman, Anand; Sharma, D N

2002-04-01

267

Accurate computation of coincidence summing corrections in low level gamma-ray spectrometry  

PubMed

The GESPECOR (Germanium Spectrometry Correction factors) software, previously developed for computing the self-attenuation and coincidence summing corrections, was applied to the computation of the coincidence summing correction factors for a well-type and two coaxial HPGe detectors. Cylindrical samples as well as Marinelli beaker samples were considered. The computed values are in good agreement with carefully measured values. A detailed study of the uncertainties assigned to the results was carried out. The analysis shows that the procedures used in GESPECOR are reliable and provide results with a well defined accuracy. PMID:10879837

Sima; Arnold

2000-07-01

268

Advanced in situ methods for the characterization of practical electrodes in lithium-ion batteries  

Microsoft Academic Search

In this paper, an overview of the progress recently achieved in our laboratory in the development and application of four in situ methods, namely in situ X-ray diffraction measurements (XRD), differential electrochemical mass spectrometry (DEMS), infrared spectroscopy, and Raman microscopy, is presented. For bulk investigations during cycling, in situ XRD measurements are used, and explained here in the instance of

P. Novák; J.-C. Panitz; F. Joho; M. Lanz; R. Imhof; M. Coluccia

2000-01-01

269

On the categorization of uranium materials using low resolution gamma ray spectrometry.  

PubMed

In order to characterize uranium materials during e.g. nuclear safeguards inspections and in initial stages of nuclear forensic investigations, hand-held low resolution gamma ray detection instruments with automatic uranium categorization capabilities may be used. In this paper, simulated response curves for a number of matrices applied on NaI(Tl) scintillation detector spectra show that the result of the categorization is strongly dependent on the physical properties of the uranium material. Recommendations on how to minimize the possibility of misclassification are discussed. PMID:23208231

Vesterlund, A; Ulvsand, T; Lidström, K; Skarnemark, G; Ekberg, C; Ramebäck, H

2012-11-02

270

Subsurface In situ elemental composition measurements with PING  

NASA Astrophysics Data System (ADS)

This paper describes the Probing In situ with Neutron and Gamma rays (PING) instrument, that can measure the subsurface elemental composition in situ for any rocky body in the solar system without the need for digging into the surface. PING consists of a Pulsed Neutron Generator (PNG), a gamma ray spectrometer and neutron detectors. Subsurface elements are stimulated by high-energy neutrons to emit gamma rays at characteristic energies. This paper will show how the detection of these gamma rays results in a measurement of elemental composition. Examples of the basalt to granite ratios for aluminum and silicon abundance are provided.

Parsons, A.; McClanahan, T.; Bodnarik, J.; Evans, L.; Nowicki, S.; Schweitzer, J.; Starr, R.

271

226Ra, 232Th and 40K analysis in soil samples from some areas of Punjab and Himachal Pradesh, India using gamma ray spectrometry  

Microsoft Academic Search

The activity concentrations and the gamma-absorbed dose rates of the terrestrial naturally occurring radio nuclides viz. 226Ra, 232Th and 40K were determined in soil samples collected from some areas of Punjab and Himachal Pradesh, using gamma ray spectrometry. The soil activity ranges from 18.22 to 90.30Bqkg-1 for 226Ra, 34.80 to 124.68Bqkg-1 for 232Th and 80.42 to 181.41Bqkg-1 for 40K with

Surinder Singh; Asha Rani; Rakesh Kumar Mahajan

2005-01-01

272

Pu abundances, concentrations, and isotopics by x- and gamma-ray spectrometry assay techniques  

SciTech Connect

Two x- and gamma-ray systems were recently installed at-line in gloveboxes and will measure Pu solution concentrations from 5 to 105 g/L. These NDA technique, developed and refined over the past decade, are now used domestically and internationally for nuclear material process monitoring and accountability needs. In off- and at-line installations, they can measure solution concentrations to 0.2%. The K-XRFA systems use a transmission source to correct for solution density. The gamma-ray systems use peaks from 59- to 208-keV to determine solution concentrations and relative isotopics. A Pu check source monitors system stability. These two NDA techniques can be combined to form a new, NDA measurement methodology. With the instrument located outside of a glovebox, both relative Pu isotopics and absolute Pu abundances of a sample located inside a glovebox can be measured. The new technique works with either single or dual source excitation; the former for a detector 6 to 20 cm away with no geometric corrections needed; the latter requires geometric corrections or source movement if the sample cannot be measured at the calibration distance. 4 refs., 7 figs., 2 tabs.

Camp, D.C.; Gunnink, R.; Ruhter, W.D.; Prindle, A.L.; Gomes, R.J.

1986-10-24

273

Natural radioactivity and radiological hazard assessment of soil using gamma-ray spectrometry.  

PubMed

Natural radioactivity in soil samples collected from different places of Bulandshahr, Hapur and Meerut city of Uttar Pradesh, India, using a low-level counting multichannel gamma-ray spectrometer system comprising an NaI(Tl) crystal. The range of (238)U, (232)Th and (40)K activity concentrations varied from 29.6 to 69.2, from 34.9 to 93.8 and from 438.2 to 719.9 , respectively. The activity concentrations of (232)Th are higher than those of (238)U in all the samples. The absorbed dose rate ranges from 53.18 to 110.95 . The values of the annual effective dose indoors are found to vary from 0.26 to 0.54 , whereas outdoors are found to vary from 0.07 to 0.14 . The annual effective dose is marginally below the international recommended value of 1 for the general public. The external and internal hazard indexes of the soil samples are below the recommended limits. The values of the gamma index in soil samples varied from 0.41 to 0.88. The values of the alpha index varied from 0.15 to 0.35. All these values of and are <1.0. It is observed from the results that there is no significant radiation hazard due to natural radionuclides of the soil samples in the studied areas. PMID:23427204

Zubair, Mohd; Verma, Deepak; Azam, Ameer; Roy, Sukanta

2013-02-20

274

Spectral information enhancement using wavelet-based iterative filtering for in vivo gamma spectrometry.  

PubMed

Use of wavelet transformation in stationary signal processing has been demonstrated for denoising the measured spectra and characterisation of radionuclides in the in vivo monitoring analysis, where difficulties arise due to very low activity level to be estimated in biological systems. The large statistical fluctuations often make the identification of characteristic gammas from radionuclides highly uncertain, particularly when interferences from progenies are also present. A new wavelet-based noise filtering methodology has been developed for better detection of gamma peaks in noisy data. This sequential, iterative filtering method uses the wavelet multi-resolution approach for noise rejection and an inverse transform after soft 'thresholding' over the generated coefficients. Analyses of in vivo monitoring data of (235)U and (238)U were carried out using this method without disturbing the peak position and amplitude while achieving a 3-fold improvement in the signal-to-noise ratio, compared with the original measured spectrum. When compared with other data-filtering techniques, the wavelet-based method shows the best results. PMID:22887117

Paul, Sabyasachi; Sarkar, P K

2012-08-11

275

Optimized background reduction in low-level gamma-ray spectrometry at a surface laboratory.  

PubMed

The background of a coaxial Ge detector placed at a surface laboratory has been reduced by means of a background reduction setup consisting of a passive shield of low-activity lead, a simple radon suppression system and an active shield with a plastic scintillation plate. In particular, we have devoted our efforts to in-depth optimization of each parameter associated with different anticoincidence setups and to their subsequent intercomparison. The overall performance of the active shield was improved by using the optimum time parameters for each setup. The final objective is to decrease the cosmic-ray background and, by this way, to reduce the detection limits of gamma-ray spectrometers at conventional laboratories, and consequently make them competitive for different measurements like (210)Pb dating. PMID:16530418

Hurtado, S; García-León, M; García-Tenorio, R

2006-03-10

276

Determination of Copper by Neutron Activation Analysis in Conjunction with Compton Suppression Gamma Spectrometry  

SciTech Connect

Copper is considered to be an essential element. Its accurate determination in tissues, foods, and other biological materials is needed to study the effect of copper on human nutrition and health. Using and Advance Prediction Computer Program, it has been shown that short-lived {sup 66}Cu (half-life = 5.09 min) can be used to determine copper in biological materials by instrumental neutron activation analysis (INAA). However, it is seldom done in practice-in particular, for low copper content in high-salt biological materials-because of the Compton background interference from nuclides such as {sup 28}Al, {sup 38}Cl, and {sup 24}Na. To eliminate the Compton interference, a preconcentration NAA method has recently been developed in our laboratory using reversed-phase extraction chromatography of copper followed by short irradiation and conventional gamma-spectrometric counting of {sup 66}Cu; the detection limit is {approx}5 ppb.

W. H. Zhang; A. Chatt

2000-06-04

277

PC/FRAM: New capabilities for the gamma-ray spectrometry measurement of plutonium isotopic composition  

SciTech Connect

We describe the new capability of and.present measurement results from the PC/FRAM plutonium isotopic analysis code. This new code allows data acquisition from a single coaxial germanium detector and analysis over an energy range from 120 keV to above I MeV. For the first time we demonstrate a complete isotopic analysis using only gamma rays greater than 200 keV in energy. This new capability allows the measurement of the plutonium isotopic composition of items inside shielded or heavy-walled containers without having to remove the items from the container. This greatly enhances worker safety by reducing handling and the resultant radiation exposure. Another application allows international inspectors to verify the contents of items inside sealed, long-term storage containers that may not be opened for national security or treaty compliance reasons. We present measurement results for traditional planar germanium detectors as well as coaxial detectors measuring shielded and unshielded samples.

Sampson, T.E.; Kelley, T.A.; Cremers, T.L.; Konkel, T.R.; Friar, R.J.

1995-10-01

278

Concentrations and their ratio of 222Rn decay products in rainwater measured by gamma-ray spectrometry using a low-background Ge detector  

Microsoft Academic Search

The concentrations and the concentration ratios of individual short-lived 222Rn decay products (214Pb and 214Bi) in rainwater were measured at Kumatori village (34.39°N, 135.35°E, approximately 70m above sea level) in Osaka, Japan, by gamma-ray spectrometry using a low-background Ge detector. The dependence of the time variations of the concentrations and their ratios on rainfall rate was investigated. It was observed

Masanori Takeyasu; Takao Iida; Tadashi Tsujimoto; Keizo Yamasaki; Yoshihiro Ogawa

2006-01-01

279

Progressive drowning of carbonate platform in the Moravo-Silesian Basin (Czech Republic) before the Frasnian\\/Famennian event: facies, compositional variations and gamma-ray spectrometry  

Microsoft Academic Search

The Moravo-Silesian Basin (MSB; eastern Czech Republic and southern Poland) hosted an extensive shallow-water carbonate platform\\u000a in the Middle Devonian to Frasnian interval. The platform drowned in a stepwise fashion from the Palmatolepis hassi to the Pa. linguiformis zone. Three types of drowning successions were revealed from conodont biostratigraphy, facies, microfacies and gamma-ray\\u000a spectrometry data: (A) drowning to periplatform turbidite

Ond?ej Bábek; TomᚠP?ikryl; Jind?ich Hladil

2007-01-01

280

Determination of Spatial Distribution Patterns of Clay and Plant Available Potassium Contents in Surface Soils at the Farm Scale using High Resolution Gamma Ray Spectrometry  

Microsoft Academic Search

Variation in dryland crop yield is often related to underlying soil properties such as water availability and soil fertility.\\u000a There are often significant difficulties in adequately defining the spatial distribution of such properties at the farm scale.\\u000a Gamma ray spectrometry (radiometrics) is a relatively new soil sensing technique that can potentially address this by improving\\u000a the mapping of soil texture

Gabriella Pracilio; Matthew L. Adams; Keith R. J. Smettem; Richard J. Harper

2006-01-01

281

On the measurement of 40 K in natural and synthetic materials by the method of high-resolution gamma-ray spectrometry  

Microsoft Academic Search

In the measurement of natural occurring radioactive material (NORM) concentrations of 40K, 232Th and 238U are measured by passive gamma ray spectrometry with either HPGe or NaI(Tl) detectors. 40K is measured through its 1460.8keV? line. However, till now it has been ignored that this line is mixed with the 1459.2keV line of 228Ac from the chain of 232Th. A correction

N. Lavi; F. Groppi; Z. B. Alfassi

2004-01-01

282

sup 6\\/LiI(Eu) in neutron and \\/spl gamma\\/-ray spectrometry-a highly sensitive thermal neutron detector  

Microsoft Academic Search

Europium doped 6LiI crystals (enriched to 96%6 Li) have been studied in neutron detection and gamma-ray spectrometry. Two crystals, 50 mmtimes5 mm and 30 mmtimes3 mm in size were coupled to a calibrated Photonis XP5200 photomultiplier, were tested. The response of 6LiI(Eu) to neutrons emitted from a paraffin moderated Pu-Be source has been investigated and the thermal neutron peak has

Agnieszka Syntfeld; M. Moszynski; R. Arlt; M. Balcerzyk; M. Kapusta; M. Majorov; R. Marcinkowski; P. Schotanus; M. Swoboda; D. Wolski

2005-01-01

283

Non-destructive determination of trace amounts of iodine in biological samples by epithermal neutron activation and Compton suppression gamma-ray spectrometry  

Microsoft Academic Search

In order to investigate the ingestion of iodine by human body and to know its content in organs, instrumental epithermal neutron activation analysis was used in conjunction with Compton suppression gamma-ray spectrometry by measuring the 128I short-lived nuclide. The interferences of 24Na and 38Cl induced from NaCl in a sample were reduced by factors of about 6 and 15 to

Ch. Yonezawa; H. Matsue; M. Yukawa

2003-01-01

284

International Workshop on Gamma Spectrometry Analysis Codes for U and Pu Isotopics: Workshop Results and Next Steps  

SciTech Connect

In November 2008, the Institute of Nuclear Materials Management (INMM) and the European Safeguards Research and Development Association (ESARDA) co-hosted the International Workshop on Gamma Spectrometry Analysis Codes for U and Pu Isotopics at the Oak Ridge National Laboratory (ORNL). This workshop was conducted in response to needs expressed by the international safeguards community to understand better the capabilities and limitations of the codes; to ensure these codes are sustained; and to ensure updates or revisions are performed in a controlled manner. The workshop was attended by approximately 100 participants. The participants included code developers, code suppliers, safeguards specialists, domestic and international inspectors, process operators, regulators, and programme sponsors from various government agencies. The workshop provided a unique opportunity for code developers, commercial distributors and end users to interact in a hands-on laboratory environment to develop solutions for programmatic and technical issues associated with the various codes. The workshop also provided an international forum for discussing development of an internationally accepted standard test method. This paper discusses the organization of the workshop, its goals and objectives and feedback received from the participants. The paper also describes the significance of the working group's contribution to improving codes that are commonly used during inspections to verify that nuclear facilities are compliant with treaty obligations that ensure nuclear fuel cycle facilities are used for peaceful purposes.

McGinnis, Brent R [ORNL; Solodov, Alexander A [ORNL; Shipwash, Jacqueline L [ORNL; Zhernosek, Alena V [ORNL; McKinney, Teressa L [ORNL; Pickett, Chris A [ORNL; Peerani, Paolo [ORNL

2009-01-01

285

LAFARA: a new underground laboratory in the French Pyrénées for ultra low-level gamma-ray spectrometry.  

PubMed

We describe a new underground laboratory, namely LAFARA (for "LAboratoire de mesure des FAibles RAdioactivités"), that was recently created in the French Pyrénées. This laboratory is primarily designed to analyze environmental samples that display low radioactivity levels using gamma-ray spectrometry. Two high-purity germanium detectors were placed under 85 m of rock (ca. 215 m water equivalent) in the tunnel of Ferrières (Ariège, France). The background is thus reduced by a factor of ?20 in comparison to above-ground laboratories. Both detectors are fully equipped so that the samples can be analyzed in an automatic mode without requiring permanent presence of a technician in the laboratory. Auto-samplers (twenty positions) and systems to fill liquid nitrogen automatically provide one month of autonomy to the spectrometers. The LAFARA facility allows us to develop new applications in the field of environmental sciences based on the use of natural radionuclides present at low levels in the environment. As an illustration, we present two of these applications: i) dating of marine sediments using the decay of (226)Ra in sedimentary barite (BaSO(4)), ii) determination of (227)Ac ((231)Pa) activities in marine sediment cores. PMID:23164692

van Beek, P; Souhaut, M; Lansard, B; Bourquin, M; Reyss, J-L; von Ballmoos, P; Jean, P

2012-11-16

286

Radon loss from encapsulated sediments in Ge gamma-ray spectrometry for the annual radiation dose determination in luminescence dating  

NASA Astrophysics Data System (ADS)

In Ge gamma-ray spectrometry for the annual radiation dose determination in the luminescence dating of sediments, the picture of 226Ra enrichment or depletion (in the 238U decay series) obtained via measurement of its 214Pb and 214Bi daughters may be disturbed by the 222Rn-content of the sample being decreased due to manipulations such as drying and pulverizing. Therefore, it is common practice to start the measurement only about 1 month after encapsulating the material, after which the 226Ra(1600 a)- 222Rn(3.82 d) mother-daughter equilibrium is re-established. Evidently, this only holds on condition that no significant escape of Rn occurs out of the sediment after making it up for counting. In order to experimentally investigate this effect, in the present work measurements were carried out with various types of dried and pulverized sediments that were either encapsulated in screw-cap polystyrene vials or in sealed glass containers, or that were mixed with molten wax followed by solidification in a cylindrical geometry. From the results obtained, it could be concluded that preparation and counting of the sediment-wax mixture is the method of choice.

de Corte, F.; Vandenberghe, D.; de Wispelaere, A.; Buylaert, J.-P.; van den Haute, P.

2006-01-01

287

In situ hybridization  

SciTech Connect

These proceedings collect papers on genetic aspects of neurobiology. Topics include: gene expression in mammalian cells, in situ hybridization with RNA probes, mRNA in brain cells, neuropeptide gene expression, genetic mapping, and localization of peptide hormone gene expression.

Valentino, K.L.; Eberwine, J.H.; Barchas, J.D.

1987-01-01

288

Determination of radium isotopes in environmental samples by gamma spectrometry, liquid scintillation counting and alpha spectrometry: a review of analytical methodology.  

PubMed

Radium (Ra) isotopes are important from the viewpoints of radiation protection and environmental protection. Their high toxicity has stimulated the continuing interest in methodology research for determination of Ra isotopes in various media. In this paper, the three most routinely used analytical techniques for Ra isotope determination in biological and environmental samples, i.e. low-background ?-spectrometry, liquid scintillation counting and ?-spectrometry, were reviewed, with emphasis on new methodological developments in sample preparation, preconcentration, separation, purification, source preparation and measurement techniques. The accuracy, selectivity, traceability, applicability and minimum detectable activity (MDA) of the three techniques were discussed. It was concluded that the MDA (0.1mBqL(-1)) of the ?-spectrometry technique coupled with chemical separation is about two orders of magnitude lower than that of low-background HPGe ?-spectrometry and LSC techniques. Therefore, when maximum sensitivity is required, the ?-spectrometry technique remains the first choice. PMID:22245211

Jia, Guogang; Jia, Jing

2012-01-14

289

Martian surface heat production and crustal heat flow from Mars Odyssey Gamma-Ray spectrometry  

NASA Astrophysics Data System (ADS)

Martian thermal state and evolution depend principally on the radiogenic heat-producing element (HPE) distributions in the planet's crust and mantle. The Gamma-Ray Spectrometer (GRS) on the 2001 Mars Odyssey spacecraft has mapped the surface abundances of HPEs across Mars. From these data, we produce the first models of global and regional surface heat production and crustal heat flow. As previous studies have suggested that the crust is a repository for approximately 50% of the radiogenic elements on Mars, these models provide important, directly measurable constraints on Martian heat generation. Our calculations show considerable geographic and temporal variations in crustal heat flow, and demonstrate the existence of anomalous heat flow provinces. We calculate a present day average surface heat production of 4.9 ± 0.3 × 10-11 W · kg-1. We also calculate the average crustal component of heat flow of 6.4 ± 0.4 mW · m-2. The crustal component of radiogenically produced heat flow ranges from <1 mW · m-2 in the Hellas Basin and Utopia Planitia regions to ˜13 mW · m-2 in the Sirenum Fossae region. These heat production and crustal heat flow values from geochemical measurements support previous heat flow estimates produced by different methodologies.

Hahn, B. C.; McLennan, S. M.; Klein, E. C.

2011-07-01

290

Depleted uranium in Kosovo: results of a survey by gamma spectrometry on soil samples.  

PubMed

The presence of depleted uranium in the soil of former Yugoslavia after the 1999 conflict raised great public concern all over the world. The so-called Balkan-syndrome is often linked with depleted uranium contamination. An excellent compilation of data about DU and its possible impact on health and environment can be found in the 1999 UNEP report and publications from the Swedish Radiation Protection Institute. Unfortunately, very few systematic and reliable data on the possible depleted uranium concentrations were until now available. Some of these rare data are only available on the web, without adequate information about the experimental procedure used. To clarify the situation, a systematic survey was started in the summer of 2000 as a collaborative effort between Ghent University (Physics Laboratory) and the Belgian Ministry of Defense (Medical Service). From 50 sites selected all over Kosovo, 150 soil samples were measured in the laboratory with a high-resolution gamma-spectrometer. Some sites (14) were explicitly selected based on military information on the use of depleted uranium munitions in the vicinity. After careful analysis we can conclude that there is no indication of any depleted uranium contamination on these 50 sites with a minimal detectable activity of 15 Bq; this corresponds approximately to 1 mg depleted uranium in a typical sample (100-150 g). PMID:12240731

Uyttenhove, J; Lemmens, M; Zizi, M

2002-10-01

291

In situ groundwater bioremediation  

SciTech Connect

In situ groundwater bioremediation of hydrocarbons has been used for more than 40 years. Most strategies involve biostimulation; however, recently bioaugmentation have been used for dehalorespiration. Aquifer and contaminant profiles are critical to determining the feasibility and strategy for in situ groundwater bioremediation. Hydraulic conductivity and redox conditions, including concentrations of terminal electron acceptors are critical to determine the feasibility and strategy for potential bioremediation applications. Conceptual models followed by characterization and subsequent numerical models are critical for efficient and cost effective bioremediation. Critical research needs in this area include better modeling and integration of remediation strategies with natural attenuation.

Hazen, Terry C.

2009-02-01

292

In situ hydrogenation  

SciTech Connect

The results of an experimental study to assess the potential of in situ hydrogenation as a method for production of heavy oils are summarized in this report. This project was designed to determine whether improvements in chemical and physical properties of oils produced by treatment of heavy oils at conditions proposed for in situ hydrogenation result from hydrogen incorporation or are primarily a consequence of thermal alteration. An experimental program was conducted in which parallel experiments were carried our under both hydrogen and nitrogen at conditions which might be expected in a reservoir under in situ hydrogenation conditions. Four different heavy oils were used as substrates: Cat Canyon crude from Santa Barbara County, California, a heavy tar from South Texas (Saner Ranch), and two Alaskan North Slope heavy oils. Reactions were carried out over simulated reservoir sands, in the presence of either water or brines representative of those in the reservoir, at temperatures ranging from 550{degree} F to 750{degree} F. Some experiments were also carried out to test the potential of catalysis of in situ hydrogenation. 29 refs., 1 fig., 15 tabs.

Stapp, P.R.

1989-12-01

293

Quantitative in situ hybridization  

Microsoft Academic Search

In situ hybridization (ISH) methods make it possible to localize specific RNA and DNA sequences in cells and tissues and are important tools for studies of cytogenetics, microbiology, gene regulation, plasticity, and differentiation. The basic prerequisite for ISH involves synthesis of a labeled DNA or RNA sequence (probe) that is complementary to the target sequence to be investigated. The probe

Lars-Inge Larsson

1997-01-01

294

In situ hydrogenation.  

National Technical Information Service (NTIS)

The results of an experimental study to assess the potential of in situ hydrogenation as a method for production of heavy oils are summarized in this report. This project was designed to determine whether improvements in chemical and physical properties o...

P. R. Stapp

1989-01-01

295

In Situ Cometary Cosmochemistry  

NASA Astrophysics Data System (ADS)

In 2014 the Rosetta space mission arrives at comet 67P. Herein we describe the ambitions of one of the instruments, Ptolemy, included on the lander. Our aim is to make in situ measurements of isotopic compositions of elements such as H, C, N and O.

Wright, I. P.; Andrews, D. J.; Barber, S. J.; Sheridan, S.; Morgan, G. H.; Morse, A. D.

2013-09-01

296

Gamma  

NSDL National Science Digital Library

The Geometric Algorithms for Modeling, Motion, and Animation (GAMMA) research group is part of the Department of Computer Science at the University of North Carolina. Some of the topics of research include haptics, "robot motion planning," collision detection, and "real-time interaction with virtual environments." There are several projects that are described in detail for each of the main areas of investigation. Many recent papers are offered that describe the progress and findings of the group's research. Additionally, there is a large collection of videos demonstrating computer animation, simulation, and interactive applications. Some software can also be downloaded for the GAMMA Web site; however, access to a few of the titles must first be approved by the system administrator.

2007-07-28

297

Determination of gamma-hydroxybutyric acid (GHB) in plasma and urine by headspace solid-phase microextraction and gas chromatography/positive ion chemical ionization mass spectrometry.  

PubMed

A new method for the qualitative and quantitative analysis of gamma-hydroxybutyric acid (GHB) in plasma and urine samples is described. It involves the conversion of GHB to gamma-butyrolactone (GBL), its subsequent headspace solid-phase microextraction (SPME), and detection by gas chromatography/positive ion chemical ionization mass spectrometry (GC/PICI-MS), using D(6)-GBL as internal standard. The assay is linear over a plasma GHB range of 1-100 microg/mL (n = 5, r = 0.999) and a urine GHB range of 5-150 microg/mL (n = 5, r = 0. 998). Relative intra- and inter-assay standard deviations, determined for plasma and urine samples at 5 and 50 microg/mL, are all below 5%. The method is simple, specific and reasonably fast. It may be applied for clinical and forensic toxicology as well as for purposes of therapeutic drug monitoring. PMID:11114057

Frison, G; Tedeschi, L; Maietti, S; Ferrara, S D

2000-01-01

298

In Situ UPb Zircon Dating Using Laser Ablation-Multi Ion Counting-ICP-MS (LA-MIC-ICP-MS)  

Microsoft Academic Search

In-situ analysis of zircons The systematics of U and Pb in zircons serve as one of the most important dating tools available in the geosciences. Until now, most zircon analyses are performed by second- ary ion mass spectrometry (SIMS) or thermal ionization mass spectrometry (TIMS). SIMS offers the possibility of in-situ analysis of single crystals at high spatial resolution. TIMS

Finnigan NEPTUNE

299

Fluorescence In Situ Hybridization  

Microsoft Academic Search

Dr. Seuss’s eloquent “One FISH, two FISH, red FISH, blue FISH” (1) could have been describing one of the most significant advancements in clinical cytogenetics, fluorescence in situ hybridization (FISH). The process, as described by Pinkel et al. in 1988 (2), involved fluorescent detection of probe DNA hybridized to chromosomal target sequences. The overall hybridization was essentially\\u000a the same one

Daynna J. Wolff; Stuart Schwartz

300

In situ leaching process  

SciTech Connect

A process is described for maintaining a relatively high and constant concentration in the leachate of an in situ leaching operation as the mineral value in the formation is depleted, and without reducing the daily production, by adjusting the pumping rate of lixiviant proportionally to the depletion of the mineral value. A method for achieving this result by increasing the residence time of the leach solution in the formation is also disclosed.

Yan, T.

1982-09-21

301

Crystalline characterization by Rutherford backscattering spectrometry and electron channelling of in situ grown YBa2Cu3O7 thin films deposited on (1 0 0) MgO by d.c. sputtering or laser ablation  

Microsoft Academic Search

YBa2Cu3O7 (YBCO) superconducting thin films have been grown in situ on single-crystal (1 0 0) MgO substrates by single target d.c. sputtering or laser ablation. The films were highly textured, with full c-axis orientation, as shown by standard ?–2? X-ray diffractometry. The inplane structure of the films was characterized by reflection high energy electron diffraction (RHEED), oscillating single-crystal photographs, Rutherford

M. Kechouane; H. L'Haridon; M. Salvi; P. N. Favennec; M. Gauneau; M. Guilloux-Viry; M. G. Karkut; C. Thivet; A. Perrin

1993-01-01

302

Measurement of Radionuclides and Gamma-Ray Dose Rate in Soil and Transfer of Radionuclides from Soil to Vegetation, Vegetable of Some Northern Area of Pakistan Using ?-Ray Spectrometry  

Microsoft Academic Search

The analysis of gamma emitters natural radionuclides, i.e., 226Ra, 232Th, and 40K, has been carried out in soil, vegetation, vegetable, and water samples collected from some Northern area of Pakistan, using\\u000a gamma-ray spectrometry. The ?-ray spectrometry was carried out using high-purity Germanium detector coupled with a computer-based\\u000a high-resolution multi-channel analyzer. The activity concentrations in soil ranges from 24.7 to 78.5 Bq?kg?1,

Hasan M. Khan; M. Ismail; Khalid Khan; Perveen Akhter

2011-01-01

303

Construction and testing of a neutron and gamma spectrometry system using pulse shape discrimination with an organic scintillator  

NASA Astrophysics Data System (ADS)

The goal of this thesis was to construct and test a neutron detector to measure the energy spectrum of 1 to 14-MeV neutrons in the presence of gammas. A spectrometer based on the process of pulse shape discrimination (PSD) was constructed, in which the scintillator NE-213 was used. The primary neutron/gamma sources used were 78-mCi and 4.7-Ci Pu-239Be sources, while 4.7-micro-Ci and 97.6-micro-Ci Na-22 gamma sources were used for energy calibration and additional testing of the detector. Proton recoil spectra and Compton electron spectra were unfolded with the neutron and gamma unfolding code FORIST to generate the incident neutron and gamma spectra, respectively. FORIST, which was written for a CDC computer, was modified to run on a VAX 6420. The experimental spectra were compared to those in the literature. The locations of the peaks in the Pu-239Be spectrum agreed with the literature to within 8.3%, the Pu-239Be gamma spectrum agreed to within 0.7%, while the Na-22 gamma spectrum agreed exactly. Uncertainties in the detection system and unfolding procedure are on the order of 5-10%. This thesis is intended to be a summary of the relevant literature and a user's guide to the PSD spectrometer.

Pope, Robert S.

1993-03-01

304

Comparison of optimised germanium gamma spectrometry and multicollector inductively coupled plasma mass spectrometry for the determination of 134Cs, 137Cs and 154Eu single ratios in highly burnt UO2  

NASA Astrophysics Data System (ADS)

Non-destructive and destructive methods have been compared to validate their corresponding assessed accuracies in the measurement of 134Cs/137Cs and 154Eu/137Cs isotopic concentration ratios in four spent UO2 fuel samples with very high (52 and 71 GWd/t) and ultra-high (91 and 126 GWd/t) burnup values, and about 10 (in the first three samples) and 4 years (in the latter sample) cooling time. The non-destructive technique tested was high-resolution gamma spectrometry using a high-purity germanium detector (HPGe) and a special tomographic station for the handling of highly radioactive 400 mm spent fuel segments that included a tungsten collimator, lead filter (to enhance the signal to Compton background ratio and reduce the dead time) and paraffin wax (to reduce neutron damage). The non-destructive determination of these isotopic concentration ratios has been particularly challenging for these segments because of the need to properly derive non-Gaussian gamma-peak areas and subtract the background from perturbing capture gammas produced by the intrinsic high-intensity neutron emissions from the spent fuel. Additionally, the activity distribution within each pin was determined tomographically to correct appropriately for self-attenuation and geometrical effects. The ratios obtained non-destructively showed a 1? statistical error in the range 1.9 2.9%. The destructive technique used was a high-performance liquid chromatographic separation system, combined online to a multicollector inductively coupled plasma mass spectrometer (HPLC-MC-ICP-MS), for the analysis of dissolved fuel solutions. During the mass spectrometric analyses, special care was taken in the optimisation of the chromatographic separation for Eu and the interfering element Gd, as also in the mathematical correction of the 154Gd background from the 154Eu signal. The ratios obtained destructively are considerably more precise (1? statistical error in the range 0.4 0.8% for most of the samples, but up to 2.8% for one sample). The HPGe gamma spectrometry can achieve a high degree of accuracy (agreement with HPLC-MC-ICP-MS within a few percent), only by virtue of the optimised setup, and the refined measurement strategy and data treatment employed.

Caruso, S.; Günther-Leopold, I.; Murphy, M. F.; Jatuff, F.; Chawla, R.

2008-05-01

305

Numerical expressions for the computation of coincidence-summing correction factors in gamma-ray spectrometry with HPGe detectors.  

PubMed

Numerical expressions to compute gamma-gamma and gamma-X(K) coincidence summing corrections were deduced by using a suitable computer program and a matrix representation of a decay scheme. For point sources only full-energy peak and total efficiencies are needed. Alternatively, values of peak-to-total ratio can be introduced. For extended sources, the same expressions can be considered with the introduction of "effective efficiencies". Examples of the use of the expressions for point sources and a particulate filter sample measured with a 60% relative efficiency HPGe detector are reported. PMID:19892555

Rizzo, S; Tomarchio, E

2009-10-22

306

Identification of bacterial N-acylhomoserine lactones (AHLs) with a combination of ultra-performance liquid chromatography (UPLC), ultra-high-resolution mass spectrometry, and in-situ biosensors.  

PubMed

N-Acylated homoserine lactones (AHLs) are produced by Gram-negative bacteria as communication signals and are frequently studied as mediators of the "quorum sensing" response of bacterial communities. Several reports have recently been published on the identification of AHLs from different species and attempts have been made to study their role in natural habitats, for example the surface of plant roots in the rhizosphere. In this article, different analytical methods, including bacterial biosensors and chromatographic techniques, are reviewed. A concept for assignment of the structures of AHLs is also presented. The retention behaviour of derivatives of AHLs containing beta-keto or hydroxyl groups and/or double bonds has been evaluated in relation to the separation behaviour of AHLs with saturated and unsubstituted alkanoyl chains. Samples have also been analysed by high resolution mass spectrometry (Fourier-transform ion-cyclotron-resonance mass spectrometry, FTICR-MS), nano liquid chromatography-electrospray ionization ion trap mass spectrometry (nano-LC-MS) and by the aid of a biosensor. The results obtained from ultra performance liquid chromatography (UPLC), FTICR-MS, nano-LC-MS, and bioassays have been compared to attempt structural characterisation of AHL without chemical synthesis of analytical standards. The method was used to identify the major AHL compound produced by the rhizosphere bacterium Acidovorax sp. N35 as N-(3-hydroxydecanoyl)homoserine lactone. PMID:17165024

Fekete, Agnes; Frommberger, Moritz; Rothballer, Michael; Li, Xiaojing; Englmann, Matthias; Fekete, Jenoe; Hartmann, Anton; Eberl, Leo; Schmitt-Kopplin, Philippe

2006-12-13

307

In-situ leaching  

SciTech Connect

The present invention relates to in-situ leaching of uranium, particularly employing an acidic leach liquor containing an oxidant, and especially in respect of ores containing significant amounts of transition metals that act as catalysts for peroxidant decomposition. When hydrogen peroxide is used as oxidant under such conditions it decomposes leading to the formation of gas bubbles and exacerbation of ore-blinding, and a reduction in the efficiency of extraction of uranium. The present invention employs peroxymonosulphuric acid as oxidant and thereby ameliorates the problems aforesaid. Preferably, additionally, sulphuric acid is present in the leach liquor and in many preferred embodiments the peroxymonosulphuric acid concentration is from 0.001 to 0.03 moles/liter and the sulphuric acid from 0.025 to 0.075 moles/liter.

Martin, B.

1982-08-17

308

Intercomparison of inductively coupled plasma mass spectrometry, quantitative neutron capture radiography, and prompt gamma activation analysis for the determination of boron in biological samples.  

PubMed

Boron determination in blood and tissue samples is a crucial task especially for treatment planning, preclinical research, and clinical application of boron neutron capture therapy (BNCT). Comparison of clinical findings remains difficult due to a variety of analytical methods, protocols, and standard reference materials in use. This paper addresses the comparability of inductively coupled plasma mass spectrometry, quantitative neutron capture radiography, and prompt gamma activation analysis for the determination of boron in biological samples. It was possible to demonstrate that three different methods relying on three different principles of sample preparation and boron detection can be validated against each other and yield consistent results for both blood and tissue samples. The samples were obtained during a clinical study for the application of BNCT for liver malignancies and therefore represent a realistic situation for boron analysis. PMID:22918535

Schütz, C L; Brochhausen, C; Hampel, G; Iffland, D; Kuczewski, B; Otto, G; Schmitz, T; Stieghorst, C; Kratz, J V

2012-08-24

309

Identification and quantification of gamma-glutamyl conjugates of biogenic amines in the nervous system of the snail, Helix aspersa, by gas chromatography-negative-ion chemical ionisation mass spectrometry.  

PubMed

The gamma-glutamyl conjugates of p-octopamine and dopamine were identified unambiguously for the first time and quantified in a single cerebral ganglion or pleural plus pedal ganglia of the snail, Helix aspersa, by gas chromatography-negative-ion chemical ionisation mass spectrometry. A new method was used for synthesis of gamma-glutamylamine standards. The concentration of gamma-glutamyltyramine was found to be low in the tissues, therefore it was used as an internal standard. The gamma-glutamylamines were extracted with water and derivatised with pentafluoropropionic anhydride and trifluoroethanol. Under negative-ion chemical ionisation conditions, the trifluoroethyl and pentafluoropropionyl derivatives produced significant ions which were sufficiently abundant to be suitable for selective ion monitoring. The method had a limit of detection of ca. 80 pg of gamma-glutamyl conjugate per tissue and calibration curves were linear over the range examined. PMID:8376522

Zhou, P; Watson, D G; Midgley, J M

1993-07-23

310

Proton-induced prompt gamma-ray spectrometry: A survey of its analytical significance and some applications  

Microsoft Academic Search

A survey was carried out of prompt gamma-rays emitted during bombardment of all stable non-gaseous elements with protons from\\u000a 3.5 to 6.0 MeV. Attainable sensitivities were calculated for the 5 most intense gamma-rays as a function of bombarding energy.\\u000a For most elements maximum sensitivity was attainable with protons between 4 and 5 MeV. Applications of the technique to the\\u000a analysis

D. Gihwala; M. Peisach

1982-01-01

311

Gamma-Ray Spectrum Catalogue. Ge(Li) and Si(Li) Spectrometry. Volume 2. Third Edition.  

National Technical Information Service (NTIS)

A new edition of the Gamma-Ray Spectrum Catalogue has been issued. The second volume of this edition which is being released at this time is devoted to the presentation of experimental pulse-amplitude spectra obtained with Ge(Li) and Si(Li) spectrometers....

R. L. Heath

1974-01-01

312

Nondestructive determination of boron and cadmium in environmental materials by thermal neutron-prompt. gamma. -ray spectrometry  

Microsoft Academic Search

Prompt ..gamma.. rays from thermal neutron induced nuclear reactions have been used to measure trace quantities of B and Cd in industrial and standard materials. The technique provides a rapid nondestructive analysis for > 0.05 ..mu..g of B. Repetitive analyses show the method to have a precision of 5%. The presence of large quantities of Na degrades the accuracy and

Ernest S. Gladney; Edward T. Jurney; David B. Curtis

1976-01-01

313

Nondestructive and quantitative characterization of TRU and LLW mixed-waste using active and passive gamma-ray spectrometry and computed tomography  

SciTech Connect

The technology being proposed by LLNL is an Active and Passive Computed Tomography (A P CT) Drum Scanner for contact-handled (CH) wastes. It combines the advantages offered by two well-developed nondestructive assay technologies: gamma-ray spectrometry and computed tomography (CT). Coupled together, these two technologies offer to nondestructively and quantitatively characterize mixed- wastes forms. Gamma-ray spectroscopy uses one or more external radiation detectors to passively and nondestructively measure the energy spectrum emitted from a closed container. From the resulting spectrum one can identify most radioactivities detected, be they transuranic isotopes, mixed-fission products, activation products or environmental radioactivities. Spectral libraries exist at LLNL for all four. Active (A) or transmission CT is a well-developed, nondestructive medical and industrial technique that uses an external-radiation beam to map regions of varying attenuation within a container. Passive (P) or emission CT is a technique mainly developed for medical application, e.g., single-photon emission CT. Nondestructive industrial uses of PCT are under development and just coming into use. This report discuses work on the A P CT Drum Scanner at LLNL.

Camp, D.C.; Martz, H.E.

1991-11-12

314

Analysis of gamma-irradiated melon, pumpkin, and sunflower seeds by electron paramagnetic resonance spectroscopy and gas chromatography-mass spectrometry.  

PubMed

Seeds of melon (Citrullus lanatus var. sp.), pumpkin (Cucurbita moschata), and sunflower (Heliantus annus) were gamma-irradiated at 1, 3, 5, and 10 kGy and analyzed by electron paramagnetic resonance (EPR) and gas chromatography-mass spectrometry (GC-MS) according to EN1787:2000 and EN1785:2003, respectively. Distinguishable triplet signals due to the presence of induced cellulose radicals were found at 2.0010-2.0047 g in the EPR spectra. The gamma-irradiated radiolytic markers of 2-dodecylcyclobutanone (2-DCB) and 2-tetradecylcyclobutanone (2-TCB) were identified in all irradiated seed samples. Both the free radicals and the alkylcyclobutanones were found to increase with irradiation dose. In general, linear relationships between the amount of radicals and irradiation dosage could be established. Studies at an ambient temperature (20-25 degrees C) in a humidity-controlled environment showed a complete disappearance of the cellulosic peaks for irradiated samples upon 60 days of storage. Such instability behavior was considered to render the usefulness of using EPR alone in the determination of irradiated seed samples. On the other hand, 2-DCB and 2-TCB were also found to decompose rapidly (>85% loss after 120 days of storage), but the radiolytic markers remained quantifiable after 120 days of postirradiation storage. These results suggest that GC-MS is a versatile and complimentary technique for the confirmation of irradiation treatment to seeds. PMID:16968077

Sin, Della W M; Wong, Yiu Chung; Yao, Wai Yin

2006-09-20

315

IN SITU STEAM EXTRACTION TREATMENT  

EPA Science Inventory

In situ steam extraction removes volatile and semivolatile hazardous contaminants from soil and groundwater without excavation of the hazardous waste. aste constituents are removed in situ by the technology and are not actually treated. he use of steam enhances the stripping of v...

316

Metallographic in situ hybridization.  

PubMed

Metallographic methods, in which a target is visualized using a probe or antibody that deposits metal selectively at its binding site, offers many advantages for bright-field in situ hybridization (ISH) detection as well as for other labeling and detection methods. Autometallographically enhanced gold labeling procedures have demonstrated higher sensitivity than conventional enzyme chromogens. Enzyme metallography, a novel procedure in which an enzymatic probe is used to deposit metal directly from solution, has been used to develop bright-field ISH methods for HER2 gene determination in breast cancer and other biopsy specimens. It provides the highest level of sensitivity and resolution, both for visualizing endogenous gene copies in nonamplified tissues and for resolving multiple gene copies to allow copy enumeration in amplified tissues without the need for oil immersion or fluorescence optics. An automated enzyme metallography procedure, silver ISH, has been developed for use in slide-staining instruments. Metallographic staining also provides excellent results for immunohistochemistry and may be combined with other staining procedures for the simultaneous detection of more than one gene or combinations of genes and proteins. PMID:17640553

Powell, Richard D; Pettay, James D; Powell, William C; Roche, Patrick C; Grogan, Thomas M; Hainfeld, James F; Tubbs, Raymond R

2007-08-01

317

Use of airborne gamma-ray spectrometry for environmental assessment of the rehabilitated nabarlek uranium mine, Australia.  

PubMed

This article describes an airborne gamma survey of a 7 x 5 km region around the rehabilitated Nabarlek uranium mine in northern Australia. An unusually tight line spacing (100 m) and low aircraft height (50 m) were used, enabling the survey to distinguish man-made structures such as ponds and accommodation areas, as well as creek lines. Positive correlations between airborne data and ground-based readings enabled an estimation of the average absorbed dose rate arising from terrestrial gamma radiation over large areas of the site to be derived. For the fenced minesite area this estimate was 0.31 micro Gy hr(- 1). The airborne survey data were found to be invaluable in helping to plan further ground-level investigations and showed promise as an assessment tool for rehabilitated minesites. PMID:16649135

Martin, Paul; Tims, Stephen; McGill, Anthony; Ryan, Bruce; Pfitzner, Kirrilly

2006-04-30

318

Pileup Correction Algorithms for Very-High-Count-Rate Gamma-Ray Spectrometry With NaI(Tl) Detectors  

Microsoft Academic Search

In this paper, we propose algorithms that are suitable for gamma-ray spectrometric systems with Nal(Tl) detector that support pileup correction at extremely high count rates of 4 ?? 106 pulses\\/s. The following two algorithms are presented: 1) an algorithm based on modified phase-only correlation (MPOC) for the detection of the beginning of pulses and maximum likelihood estimation (MLE) for the

Miodrag Bolic; Vujo Drndarevic; Wail Gueaieb

2010-01-01

319

Peak efficiency calibration for attenuation corrected cylindrical sources in gamma ray spectrometry by the use of a point source.  

PubMed

A theoretical method of determining the gamma-ray peak efficiency for a cylindrical source, based on a modified expression for point sources is derived. A term for the photon self-attenuation is included in the calculation. The method is valid for any source material as long as the source activity concentration is considered to be homogeneous. Results of this expression are checked against experimental data obtained with (241)Am, (57)Co, (137)Cs, and (60)Co sources. PMID:16854587

Aguiar, Julio C; Galiano, Eduardo; Fernandez, Jorge

2006-07-18

320

Rapid determination of radon daughters and of artificial radionuclides in air by online gamma-ray spectrometry  

Microsoft Academic Search

For the determination of airborne radionuclide concentrations in real time, a fixed filter device was constructed which fits directly onto a germanium detector with standard nuclear electronics and a multichannel analyzer buffer connected via a data line to a personal computer for remote control and on-line spectrum evaluation. The on-line gamma-ray spectrometer was applied to the study of radon decay

H. Hiitzl; R. Winkler

1993-01-01

321

Monte Carlo simulation of the self-absorption corrections for natural samples in gamma-ray spectrometry  

Microsoft Academic Search

Gamma-ray self-attenuation corrections in the energy range 60–2000keV were evaluated by means of Monte Carlo calculations for environmental samples in a cylindrical measuring geometry. The dependence of the full-energy peak efficiency on the sample density was obtained for some particular photon energies and, as a result, the corresponding self-attenuation correction factors were obtained. The calculations were performed by assuming that

M. Jurado Vargas; A. Fernández Timón; N. Cornejo D??az; D. Pérez Sánchez

2002-01-01

322

Determination of total fluorine in five coal reference materials by proton-induced gamma-ray emission spectrometry  

Microsoft Academic Search

The direct non-destructive proton-induced gamma-ray emission (PIGE) technique with a germanium detector was applied to the determination of total fluorine concentration in five coal reference materials (BCR 40, NIST 1632b, NIST 1635, SARM 20 and USGS CLB-1). Duplicate analyses were made from five randomly selected bottles of each coal. Individual data are presented and some problems (calibration, proton stopping power,

I. Roelandts; G. Robaye; J. M. Delbrouck-Habaru; G. Weber

1996-01-01

323

Determination of soil depth profiles for 137 Cs and 210 Pb using gamma-ray spectrometry with Compton suppression  

Microsoft Academic Search

Summary  137Cs and to a lesser extent, 210Pb have been widely used for soil erosion and sedimentation studies. The accuracy of their quantification is greatly dependent on the proper handling of the sources of error that may affect the results. These include ambient background variation, attenuation for the 210Pb 45 keV gamma-photons in the sample, efficiency calibration and large statistical errors

S. Landsberger

2005-01-01

324

In situ leach method  

SciTech Connect

A method is described for the in situ leaching of uranium and/or related values from a subterranean deposit. The method consists of: drilling at least one injection well and at least one production well into the deposit at spaced intervals from each other; completing the at least one production well so that the production well has a gravel pack therein lying adjacent the deposit; injecting a leach solution into the deposit through the injection well and flowing the leach solution through the deposit to dissolve uranium and/or related values therein; filtering the leach solution and the uranium and/or related values dissolved therein through the gravel pack as the leach solution and dissolve uranium and/or related values flows into the production well to remove substantially all of any particular material and/or sediment entrained in the leach solution; flowing the leach solution and dissolved uranium and/or related values from the production well and downward through a bed of an ion exchange resin without additional filtering of particulate material from the leach solution; absorbing the uranium and/or related values from the leach solution on the bed of ion exchange resin as the leach solution flows downward therethrough; filtering substantially all of any remaining particulate material and/or sediment from the leach solution into the bed of ion exchange resin as the leach solution flows downward therethrough; and adding leach chemicals to the leach solution after the leach solution has flowed through the bed of ion exchange resin without any further filtering of particulate materials and/or sediment from the leach solution to thereby makeup fresh leach solution for recycle in the leaching operation.

Mays, W.M.

1986-03-11

325

Environmental Assessment of In Situ Mining.  

National Technical Information Service (NTIS)

This study evaluates selective environmental impacts of two distinct in situ mining techniques. In situ leaching of uranium, porphyry copper, and native copper and in situ borehole slurry mining of uranium, sandstone, and pebble phosphate ores are the tec...

C. K. Chase D. R. Kasper H. W. Martin L. D. Munsey R. B. Bhappu

1979-01-01

326

Measurement of radionuclides and absorbed dose rates in soil samples of Peshawar, Pakistan, using gamma ray spectrometry  

Microsoft Academic Search

The analysis of gamma-emitting radionuclides in nature, i.e. Ra, Th, K and Cs, has been carried out in soil samples collected from Peshawar University Campus and surrounding areas using a high purity germanium detector coupled with a computer-based high-resolution multichannel analyser. The activity concentrations in soil ranged from 30.20±0.65 to 61.90±0.95, 50.10±0.54 to 102.80±1.04, 373.60±4.56 to 1082±11.38 and 9.50±0.11 to

Hasan M. Khan; Muhammad Ismail; Muhammad Abid Zia; Khalid Khan

2012-01-01

327

Determination of the natural radioactivity levels in north west of Dukhan, Qatar using high-resolution gamma-ray spectrometry.  

PubMed

This study is aimed at the determination of the activity concentrations of naturally occuring and technologically enhanced levels of radiation in 34 representative soil samples that have been collected from an inshore oil field area which was found to have, in a previous study, the highest observed value of 226Ra concentration among 129 soil samples. The activity concentrations of 238U and 226Ra have been inferred from gamma-ray transitions associated with their decay progenies and measured using a hyper-pure germanium detector. Details of the sample preparation and the gamma-ray spectroscopic analysis techniques are presented, together with the values of the activity concentrations associated with the naturally occuring radionuclide chains for all the samples collected from NW Dukhan. Discrete-line, gamma-ray energy transitions from spectral lines ranging in energy from ?100 keV up to 2.6 MeV have been associated with characteristic decays of the various decay products within the 235.8U and 232Th radioactive decay chains. These data have been analyzed, under the assumption of secular equilibrium for the U and Th decay chains. Details of the sample preparation and the gamma-ray spectroscopic analysis techniques are presented. The weighted mean value of the activity concentrations of 226Ra in one of the samples was found to be around a factor of 2 higher than the values obtained in the previous study and approximately a factor of 10 higher than the accepted worldwide average value of 35 Bq/kg. The weighted mean values of the activity concentrations of 232Th and 40K were also deduced and found to be within the worldwide average values of 30 and 400 Bq/kg, respectively. Our previous study reported a value of 201.9±1.5Stat.±13Syst.Bq/kg for 226Ra in one sample and further investigation in the current work determined a measured value for 226Ra of 342.00±1.9Stat.±25Syst.Bq/kg in a sample taken from the same locality. This is significantly higher than all the other investigated soil samples in the current and previous works. Notably, the Th levels in the same sample are within the worldwide average expectations, implying that the increased 226Ra concentration arises from TENORM processes. PMID:22244196

Al-Sulaiti, Huda; Nasir, Tabassum; Al Mugren, K S; Alkhomashi, N; Al-Dahan, N; Al-Dosari, M; Bradley, D A; Bukhari, S; Matthews, M; Regan, P H; Santawamaitre, T; Malain, D; Habib, A

2011-12-16

328

In-situ characterization technique for screening contaminated soils  

Microsoft Academic Search

An innovative field sampling system for screening contaminated soils has been developed using laser ablation coupled with inductively coupled plasma-atomic emission spectrometry (LA-ICP-AES) technology. This sampling approach provides in-situ real-time analysis of trace inorganic elements and is conducted through a mobile testing facility that consists of an instrumentation vehicle called the Mobile Demonstration Laboratory for Environmental Screening Technologies (MDLEST) and

Edward J. Jaselskis; Marvin S. Anderson; Arthur P. D'Silva; David P. Baldwin; Daniel S. Zamzow

1995-01-01

329

FISH - (Fluoresence In Situ Hybridization)  

NSDL National Science Digital Library

Fluorescence in situ hybridization (FISH) is a process which vividly paints chromosomes or portions of chromosomes with fluorescent molecules. This technique is useful for identifying chromosomal abnormalities and gene mapping.

Darryl Leja (National Human Genome Research Institute REV)

2005-04-04

330

IN SITU ENHANCED SOURCE REMOVAL  

EPA Science Inventory

This html report describes and compares the performance of in situ technologies designed to accelerate the removal of organic contaminants from unconsolidated soils and aquifers. The research was conducted through the Enhanced Source Removal (ESR) Program within the Subsurface Pr...

331

An analytical calculation of the peak efficiency for cylindrical sources perpendicular to the detector axis in gamma-ray spectrometry.  

PubMed

An analytical expression for the so-called full-energy peak efficiency epsilon(E) for cylindrical source with perpendicular axis to an HPGe detector is derived, using point-source measurements. The formula covers different measuring distances, matrix compositions, densities and gamma-ray energies; the only assumption is that the radioactivity is homogeneously distributed within the source. The term for the photon self-attenuation is included in the calculation. Measurements were made using three different sized cylindrical sources of 241Am, 57Co, 137Cs, 54Mn, and 60Co with corresponding peaks of 59.5, 122, 662, 835, 1173, and 1332 keV, respectively, and one measurement of radioactive waste drum for 662, 1173, and 1332 keV. PMID:18249126

Aguiar, Julio C

2007-12-23

332

The use of MCNP and gamma spectrometry in supporting the evaluation of NORM in Libyan oil pipeline scale  

NASA Astrophysics Data System (ADS)

The accumulation of scales in production pipes is a common problem in the oil industry, reducing fluid flow and also leading to costly remedies and disposal issues. Typical materials found in such scale are sulphates and carbonates of calcium and barium, or iron sulphide. Radium arising from the uranium/thorium present in oil-bearing rock formations may replace the barium or calcium in these salts to form radium salts. This creates what is known as technologically enhanced naturally occurring radioactive material (TENORM or simply NORM). NORM is a serious environmental and health and safety issue arising from commercial oil and gas extraction operations. Whilst a good deal has been published on the characterisation and measurement of radioactive scales from offshore oil production, little information has been published regarding NORM associated with land-based facilities such as that of the Libyan oil industry. The ongoing investigation described in this paper concerns an assessment of NORM from a number of land based Libyan oil fields. A total of 27 pipe scale samples were collected from eight oil fields, from different locations in Libya. The dose rates, measured using a handheld survey meter positioned on sample surfaces, ranged from 0.1-27.3 ?Sv h-1. In the initial evaluations of the sample activity, use is being made of a portable HPGe based spectrometry system. To comply with the prevailing safety regulations of the University of Surrey, the samples are being counted in their original form, creating a need for correction of non-homogeneous sample geometries. To derive a detection efficiency based on the actual sample geometries, a technique has been developed using a Monte Carlo particle transport code (MCNPX). A preliminary activity determination has been performed using an HPGe portable detector system.

Habib, Ahmed S.; Bradley, D. A.; Regan, P. H.; Shutt, A. L.

2010-07-01

333

Nanoparticles laden in situ gel for sustained ocular drug delivery  

PubMed Central

Proper availability of drug on to corneal surface is a challenging task. However, due to ocular physiological barriers, conventional eye drops display poor ocular bioavailability of drugs (< 1%). To improve precorneal residence time and ocular penetration, earlier our group developed and evaluated in situ gel and nanoparticles for ocular delivery. In interest to evaluate the combined effect of in situ gel and nanoparticles on ocular retention, we combined them. We are the first to term this combination as “nanoparticle laden in situ gel”, that is, poly lactic co glycolic acid nanoparticle incorporated in chitosan in situ gel for sparfloxacin ophthalmic delivery. The formulation was tested for various physicochemical properties. It showed gelation pH near pH 7.2. The observation of acquired gamma camera images showed good retention over the entire precorneal area for sparfloxacin nanoparticle laden in situ gel (SNG) as compared to marketed formulation. SNG formulation cleared at a very slow rate and remained at corneal surface for longer duration as no radioactivity was observed in systemic circulation. The developed formulation was found to be better in combination and can go up to the clinical evaluation and application.

Gupta, Himanshu; Aqil, Mohammed; Khar, Roop K.; Ali, Asgar; Bhatnagar, Aseem; Mittal, Gaurav

2013-01-01

334

Triplex in-situ hybridization  

DOEpatents

Disclosed are methods for detecting in situ the presence of a target sequence in a substantially double-stranded nucleic acid segment, which comprises: a) contacting in situ under conditions suitable for hybridization a substantially double-stranded nucleic acid segment with a detectable third strand, said third strand being capable of hybridizing to at least a portion of the target sequence to form a triple-stranded structure, if said target sequence is present; and b) detecting whether hybridization between the third strand and the target sequence has occured.

Fresco, Jacques R. (Princeton, NJ); Johnson, Marion D. (East Windsor, NJ)

2002-01-01

335

The In Situ Vitrification Project  

Microsoft Academic Search

The Columbia Section of the American Society of Civil Engineers (ASCE) is pleased to submit the In Situ Vitrification (ISV) Project to the Pacific Northwest Council for consideration as the Outstanding Civil Engineering Achievement. The ISV process, developed by Battelle-Northwest researchers beginning in 1980, converts contaminated soils and sludges to a glass and crystalline product. In this way it stabilizes

Buelt

1988-01-01

336

In situ biofilm coupon device  

DOEpatents

An apparatus for characterization of in-situ microbial biofilm populations in subsurface groundwater. The device permits biofilm-forming microorganisms to adhere to packing material while emplaced in a groundwater strata, so that the packing material can be later analyzed for quantity and type of microorganisms, growth rate, and nutrient requirements.

Peyton, Brent M. (Kennewick, WA); Truex, Michael J. (Richland, WA)

1997-01-01

337

In situ biofilm coupon device  

DOEpatents

An apparatus is disclosed for characterization of in-situ microbial biofilm populations in subsurface groundwater. The device permits biofilm-forming microorganisms to adhere to packing material while emplaced in a groundwater strata, so that the packing material can be later analyzed for quantity and type of microorganisms, growth rate, and nutrient requirements. 3 figs.

Peyton, B.M.; Truex, M.J.

1997-06-24

338

Controlled In-situ Etchback.  

National Technical Information Service (NTIS)

A controlled in situ etch-back technique is in which an etch melt and a growth melt are first saturated by a source-seed crystal is described. Etchback of a substrate then takes plce by the slightly undersaturated etch melt. This is followed by liquid pha...

A. C. Seabaugh R. J. Mattauch

1981-01-01

339

Strategies for In situ and Sample Return Analyses  

NASA Astrophysics Data System (ADS)

There is general agreement that planetary exploration proceeds from orbital reconnaissance of a planet, to surface and near-surface in situ exploration, to sample return missions, which bring back samples for investigations in terrestrial laboratories, using the panoply of state-of-the-art analytical techniques. The applicable techniques may depend on the nature of the returned material and complementary and multi- disciplinary techniques can be used to best advantage. High precision techniques also serve to provide the "ground truth" and calibrate past and future orbital and in situ measurements on a planet. It is also recognized that returned samples may continue to be analyzed by novel techniques as the techniques become developed, in part to address specific characteristics of returned samples. There are geophysical measurements such as those of the moment of inertia of a planet, seismic activity, and surface morphology that depend on orbital and in-situ science. Other characteristics, such as isotopic ages and isotopic compositions (e.g., initial Sr and Nd) as indicators of planetary mantle or crust evolution and sample provenance require returned samples. In situ analyses may be useful for preliminary characterization and for optimization of sample selection for sample return. In situ analyses by Surveyor on the Moon helped identify the major element chemistry of lunar samples and the need for high precision mass spectrometry (e. g., for Rb-Sr ages, based on extremely low alkali contents). The discussion of in-situ investigations vs. investigations on returned samples must be directly related to available instrumentation and to instrumentation that can be developed in the foreseeable future. The discussion of choices is not a philosophical but instead a very practical issue: what precision is required for key investigations and what is the instrumentation that meets or exceeds the required precision. This must be applied to potential in situ instruments and to laboratory instruments. Age determinations and use of isotopes for deciphering planetary evolution are viewed as off-limits for in-situ determinations, as they require: a) typically high precision mass spectrometry (at 0.01% and below); b) the determination of parent-daughter element ratios at least at the percent level; c) the measurement of coexisting minerals (for internal isochron determinations); d) low contamination (e. g., for U-Pb and Pb-Pb); and e) removal of adhering phases and contaminants, not related to the samples to be analyzed. Total K-Ar age determinations are subject to fewer requirements and may be feasible, in situ, but in the absence of neutron activation, as required for 39Ar-40Ar, the expected precision is at the level of ~20%, with trapped Ar in the samples introducing further uncertainty. Precision of 20% for K-Ar may suffice to address some key cratering rate uncertainties on Mars, especially as applicable to the Middle Amazonian(1). For in situ, the key issues, which must be addressed for all measurements are: what precision is required and are there instruments available, at the required precision levels. These issues must be addressed many years before a mission gets defined. Low precision instruments on several in situ missions that do not address key scientific questions may in fact be more expensive, in their sum, than a sample return mission. In summary, all missions should undergo similar intense scrutiny with regard to desired science and feasibility, based on available instrumentation (with demonstrated and known capabilities) and cost. 1. P. T. Doran et al. (2004) Earth Sci. Rev. 67, 313-337.

Papanastassiou, D. A.

2006-12-01

340

In Situ Analytical Electron Microscopy for Probing Nanoscale Electrochemistry  

SciTech Connect

Oxides and their tailored structures are at the heart of electrochemical energy storage technologies and advances in understanding and controlling the dynamic behaviors in the complex oxides, particularly at the interfaces, during electrochemical processes will catalyze creative design concepts for new materials with enhanced and better-understood properties. Such knowledge is not accessible without new analytical tools. New innovative experimental techniques are needed for understanding the chemistry and structure of the bulk and interfaces, more importantly how they change with electrochemical processes in situ. Analytical Transmission Electron Microscopy (TEM) is used extensively to study electrode materials ex situ and is one of the most powerful tools to obtain structural, morphological, and compositional information at nanometer scale by combining imaging, diffraction and spectroscopy, e.g., EDS (energy dispersive X-ray spectrometry) and Electron Energy Loss Spectrometry (EELS). Determining the composition/structure evolution upon electrochemical cycling at the bulk and interfaces can be addressed by new electron microscopy technique with which one can observe, at the nanometer scale and in situ, the dynamic phenomena in the electrode materials. In electrochemical systems, for instance in a lithium ion battery (LIB), materials operate under conditions that are far from equilibrium, so that the materials studied ex situ may not capture the processes that occur in situ in a working battery. In situ electrochemical operation in the ultra-high vacuum column of a TEM has been pursued by two major strategies. In one strategy, a 'nano-battery' can be fabricated from an all-solid-state thin film battery using a focused ion beam (FIB). The electrolyte is either polymer based or ceramic based without any liquid component. As shown in Fig. 1a, the interfaces between the active electrode material/electrolyte can be clearly observed with TEM imaging, in contrast to the composite electrodes/electrolyte interfaces in conventional lithium ion batteries, depicted in Fig.1b, where quantitative interface characterization is extremely difficult if not impossible. A second strategy involves organic electrolyte, though this approach more closely resembles the actual operation conditions of a LIB, the extreme volatility In Situ Analytical Electron Microscopy for Probing Nanoscale Electrochemistry by Ying Shirley Meng, Thomas McGilvray, Ming-Che Yang, Danijel Gostovic, Feng Wang, Dongli Zeng, Yimei Zhu, and Jason Graetz of the organic electrolytes present significant challenges for designing an in situ cell that is suitable for the vacuum environment of the TEM. Significant progress has been made in the past few years on the development of in situ electron microscopy for probing nanoscale electrochemistry. In 2008, Brazier et al. reported the first cross-section observation of an all solid-state lithium ion nano-battery by TEM. In this study the FIB was used to make a 'nano-battery,' from an all solid-state battery prepared by pulsed laser deposition (PLD). In situ TEM observations were not possible at that time due to several key challenges such as the lack of a suitable biasing sample holder and vacuum transfer of sample. In 2010, Yamamoto et al. successfully observed changes of electric potential in an all-solid-state lithium ion battery in situ with electron holography (EH). The 2D potential distribution resulting from movement of lithium ions near the positive-electrode/electrolyte interface was quantified. More recently Huang et al. and Wang et al. reported the in situ observations of the electrochemical lithiation of a single SnO{sub 2} nanowire electrode in two different in situ setups. In their approach, a vacuum compatible ionic liquid is used as the electrolyte, eliminating the need for complicated membrane sealing to prevent the evaporation of carbonate based organic electrolyte into the TEM column. One main limitation of this approach is that EELS spectral imaging is not possible due to the high plasmon signal of the ionic li

Graetz J.; Meng, Y.S.; McGilvray, T.; Yang, M.-C.; Gostovic, D.; Wang, F.; Zeng, D.; Zhu, Y.

2011-10-31

341

A transportable high-resolution gamma-ray spectrometer and analysis system applicable to mobile, autonomous or unattended applications  

SciTech Connect

The Safeguards Technology Program at the Lawrence Livermore National Laboratory is developing systems based on a compact electro-mechanically cooled high-purity germanium (HPGe) detector. This detector system broadens the practicality of performing high- resolution gamma-ray spectrometry in the field. Utilizing portable computers, multi-channel analyzers and software these systems greatly improve the ease of performing mobile high-resolution gamma-ray spectrometry. Using industrial computers, we can construct systems that will run autonomously for extended periods of time without operator input or maintenance. These systems can start or make decisions based on sensor inputs rather than operator interactions. Such systems can provide greater capability for wider domain of safeguards, treaty verification application, and other unattended, autonomous or in-situ applications.

Buckley, W.M.; Neufeld, K.W.

1995-07-01

342

Verification of the 239Pu content, isotopic composition and age of plutonium in Pu–Be neutron sources by gamma-spectrometry  

Microsoft Academic Search

A non-destructive, gamma-spectrometric method for verifying the plutonium content of Pu–Be neutron sources has been developed. Gamma-spectra were taken in the far-field of the sample, which was assumed to be cylindrical. The Pu content of the sources was evaluated from the count rates of the gamma-peaks of 239Pu, relying on the assumption that the gamma-rays are coming to the detector

Cong Tam Nguyen

2006-01-01

343

Verification of the 239Pu content, isotopic composition and age of plutonium in Pu Be neutron sources by gamma-spectrometry  

Microsoft Academic Search

A non-destructive, gamma-spectrometric method for verifying the plutonium content of Pu Be neutron sources has been developed. Gamma-spectra were taken in the far-field of the sample, which was assumed to be cylindrical. The Pu content of the sources was evaluated from the count rates of the gamma-peaks of 239Pu, relying on the assumption that the gamma-rays are coming to the

Cong Tam Nguyen

2006-01-01

344

In situ mass spectrometry during the Lutetia flyby  

NASA Astrophysics Data System (ADS)

During the Rosetta flyby at asteroid Lutetia the ROSINA instrument tried to detect a thin exosphere of the asteroid. Although the instrument is sensitive enough to detect even very tenuous gases at a density level of 1 cm-3 the Lutetia exosphere could not be unambiguously detected due to spacecraft outgassing, which was not constant because of the changing solar aspect angle. An upper limit for a water exosphere density at the flyby distance of 3160 km of (3.5±1.0)×103 cm-3 was deduced from the measurements.

Altwegg, K.; Balsiger, H.; Calmonte, U.; Hässig, M.; Hofer, L.; Jäckel, A.; Schläppi, B.; Wurz, P.; Berthelier, J. J.; De Keyser, J.; Fiethe, B.; Fuselier, S.; Mall, U.; Rème, H.; Rubin, M.

2012-06-01

345

In-situ Rb-Sr geochronology  

NASA Astrophysics Data System (ADS)

This paper reports on the first rubidium-strontium (Rb-Sr) radiometric dates using a Laser Desorption Resonance Ionization Mass Spectrometry (LDRIMS) instrument capable of being miniaturized for flight to another planet. The LDRIMS instrument produces dates in under 24 hours, requires minimal sample preparation, and avoids the interference and mass resolution issues associated with other geochronology measurements. We have begun testing the bench-top prototype on the Boulder Creek Granite (BCG), from Colorado, comprised primarily of a gneissic quartz monzonite and granodiorite; whole rock Rb-Sr TIMS measurements result in dates of 1700± 40 Ma [1]. Data reduction of the LDRIMS Rb-Sr measurements on calibrated repeat runs result in a date for the BCG of 1.727± 0.087 Ga (n=288, MSWD=1). Most geochronology applications are willing to accept an MSWD up to ~2.7; at MSWD=2, the precision improves to ± 0.062 Ga. This technology is moving from lab prototype to field deployable instrument, and provides an opportunity to directly address the science goals of Mars Sample Return (MSR) within the bounds posed by current scientific, fiscal, and political pressures on the Mars program. Additionally, LDRIMS could potentially be flown to the Moon under the Discovery or New Frontiers program. We posit that in-situ geochronology missions to Mars to triage and validate samples for Mars Sample Return (MSR) are technically feasible in the 2018-2022 time frame.

Anderson, F. S.; Nowicki, K.; Whitaker, T.

346

Amplification of chromosomal DNA in situ  

Microsoft Academic Search

Amplification of chromosomal DNA in situ to increase the amount of DNA associated with a chromosome or chromosome region is described. The amplification of chromosomal DNA in situ provides for the synthesis of Fluorescence in situ Hybridization (FISH) painting probes from single dissected chromosome fragments, the production of cDNA libraries from low copy mRNAs and improved in Comparative Genomic Hybridization

Allen T. Christian; Matthew A. Coleman; James D. Tucker

2002-01-01

347

Routine application of the in situ soil analysis technique by the Yankee Atomic Environmental Laboratory  

Microsoft Academic Search

Using a technique developed by the Environmental Measurements Laboratory (EML) for field spectrometry, the Yankee Atomic Environmental Laboratory (YAEL) has routinely performed in situ soil measurements in the vicinity of five nuclear power stations for more than a decade. As a special research endeavor, several locations at the FURNAS Angra 1 site in Brazil having high natural backgrounds were also

J. C. Murray; D. E. McCurdy; E. L. Laurenzo

1989-01-01

348

Radiation metabolomics. 3. Biomarker discovery in the urine of gamma-irradiated rats using a simplified metabolomics protocol of gas chromatography-mass spectrometry combined with random forests machine learning algorithm.  

PubMed

Abstract Radiation metabolomics employing mass spectral technologies represents a plausible means of high-throughput minimally invasive radiation biodosimetry. A simplified metabolomics protocol is described that employs ubiquitous gas chromatography-mass spectrometry and open source software including random forests machine learning algorithm to uncover latent biomarkers of 3 Gy gamma radiation in rats. Urine was collected from six male Wistar rats and six sham-irradiated controls for 7 days, 4 prior to irradiation and 3 after irradiation. Water and food consumption, urine volume, body weight, and sodium, potassium, calcium, chloride, phosphate and urea excretion showed major effects from exposure to gamma radiation. The metabolomics protocol uncovered several urinary metabolites that were significantly up-regulated (glyoxylate, threonate, thymine, uracil, p-cresol) and down-regulated (citrate, 2-oxoglutarate, adipate, pimelate, suberate, azelaate) as a result of radiation exposure. Thymine and uracil were shown to derive largely from thymidine and 2'-deoxyuridine, which are known radiation biomarkers in the mouse. The radiation metabolomic phenotype in rats appeared to derive from oxidative stress and effects on kidney function. Gas chromatography-mass spectrometry is a promising platform on which to develop the field of radiation metabolomics further and to assist in the design of instrumentation for use in detecting biological consequences of environmental radiation release. PMID:19630524

Lanz, Christian; Patterson, Andrew D; Slavík, Josef; Krausz, Kristopher W; Ledermann, Monika; Gonzalez, Frank J; Idle, Jeffrey R

2009-08-01

349

Measurement of Absolute Fission Yields in the Fast Neutron-Induced Fission of Actinides: {sup 238}U, {sup 237}Np, {sup 238}Pu, {sup 240}Pu, {sup 243}Am, and {sup 244}Cm by Track-Etch-cum-Gamma Spectrometry  

SciTech Connect

The absolute fission yields of 46 fission products in {sup 238}U (99.9997 at.%), 46 fission products in {sup 237}Np, 27 fission products in {sup 238}Pu (99.21 at.%), 30 fission products in {sup 240}Pu (99.48 at.%), 30 fission products in {sup 243}Am (99.998 at.%), and 32 fission products in {sup 244}Cm (99.43 at.%) induced by fast neutrons were determined using a fission track-etch-cum-gamma spectrometric technique. In the case of highly alpha-active and sparingly available actinides - e.g., {sup 238}Pu, {sup 240}Pu, {sup 243}Am, and {sup 244}Cm - a novel recoil catcher technique to collect the fission products on a Lexan polycarbonate foil followed by gamma-ray spectrometry was developed during the course of this work. This completely removed interferences from (a) gamma rays of daughter products in secular equilibrium with the target nuclide (e.g., {sup 243}Am-{sup 239}Np), (b) activation products of the catcher foil [e.g., {sup 24}Na from Al(n,{alpha})], and (c) activation products of the target [e.g., {sup 238}Np from {sup 237}Np(n,{gamma}) and {sup 239}Np from {sup 238}U(n,{gamma})] reactions, making the gamma spectrometric analysis very simple and accurate. The high-yield asymmetric fission products were analyzed by direct gamma spectrometry, whereas the low-yield symmetric products (e.g., Ag, Cd, and Sb) as well as some of the asymmetric fission products (e.g., Br) and rare earths (in the case of {sup 238}U and {sup 237}Np) were radiochemically separated and then analyzed by gamma-ray spectrometry. The neutron spectra in the irradiation positions of the reactors were measured and delineated in the thermal to 10-MeV region using threshold activation detectors. The present data were compared with the ENDF/VI and UKFY2 evaluated data files. From the measured cumulative yields, the mass-chain yields have been deduced using charge distribution systematics. The mass yields, along with similar data for other fast neutron-induced fissioning systems, show several important features:1. Fine structure in the interval of five mass units in even-Z fissioning systems due to odd-even effects. The fine structure decreases from lighter to heavier even-Z actinides, in accordance with their odd-even effect.2. Higher yields in the mass regions 133 to 135, 138 to 140, and 143 to 145 and their complementary mass regions, depending on the mass of the fissioning systems due to the presence of 82n-66n, 86n-62n, and 88n-56n shells.3. For odd-Z fissioning systems having no odd-even effect, the fine structure is very feeble and is due only to shell effects.4. Unusually high yields observed in the mass region 133 to 139 in the fissioning system {sup 239}U* as compared to other U isotopes are explained on the basis of a higher neutron-to-proton ratio (N/Z) of {sup 238}U compared to lower-mass uranium isotopes. The {nu}-bar, full-width at tenth-maximum, and A{sub L}-bar increase with increasing mass of the fissioning systems, whereas A{sub H}-bar of {approx}139 {+-} 1 remains constant throughout due to the strong preference for the formation of the deformed 88n shell, which is also favorable from the N/Z point of view.

Iyer, R.H.; Naik, H.; Pandey, A.K.; Kalsi, P.C.; Singh, R.J.; Ramaswami, A.; Nair, A.G.C. [Bhaha Atomic Research Centre (India)

2000-07-15

350

Chemical ionization tandem mass spectrometer for the in situ measurement of methyl hydrogen peroxide  

SciTech Connect

A new approach for measuring gas-phase methyl hydrogen peroxide [(MHP) CH{sub 3}OOH] utilizing chemical ionization mass spectrometry is presented. Tandem mass spectrometry is used to avoid mass interferences that hindered previous attempts to measure atmospheric CH{sub 3}OOH with CF{sub 3}O{sup -} clustering chemistry. CH{sub 3}OOH has been successfully measured in situ using this technique during both airborne and ground-based campaigns. The accuracy and precision for the MHP measurement are a function of water vapor mixing ratio. Typical precision at 500 pptv MHP and 100 ppmv H{sub 2}O is {+-}80 pptv (2 sigma) for a 1 s integration period. The accuracy at 100 ppmv H{sub 2}O is estimated to be better than {+-}40%. Chemical ionization tandem mass spectrometry shows considerable promise for the determination of in situ atmospheric trace gas mixing ratios where isobaric compounds or mass interferences impede accurate measurements.

St Clair, Jason M.; McCabe, David C. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125 (United States); Crounse, John D. [Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, California 91125 (United States); Steiner, Urs [Varian, Inc., Santa Clara, California 95051 (United States); Wennberg, Paul O. [Division of Geological and Planetary Sciences, California Institute of Technology, Pasadena, California 91125 (United States); Division of Engineering and Applied Science, California Institute of Technology, Pasadena, California 91125 (United States)

2010-09-15

351

In-situ spectrophotometric probe  

DOEpatents

A spectrophotometric probe for in situ absorption spectra measurements comprising a first optical fiber carrying light from a remote light source, a second optical fiber carrying light to a remote spectrophotometer, the proximal ends of the first and second optical fibers parallel and coterminal, a planoconvex lens to collimate light from the first optical fiber, a reflecting grid positioned a short distance from the lens to reflect the collimated light back to the lens for focussing on the second optical fiber. The lens is positioned with the convex side toward the optical fibers. A substrate for absorbing analyte or an analyte and reagent mixture may be positioned between the lens and the reflecting grid.

Prather, William S. (2419 Dickey Rd., Augusta, GA 30906)

1992-01-01

352

Simulations of terrestrial in-situ cosmogenic-nuclide production  

NASA Astrophysics Data System (ADS)

Targets of silicon and silicon dioxide were irradiated with spallation neutrons to simulate the production of long-lived radionuclides in the surface of the earth. Gamma-ray spectroscopy was used to measure Be-7 and Na-22, and accelerator mass spectrometry was used to measure Be-10, C-14, and Al-26. The measured ratios of these nuclides are compared with calculated ratios and with ratios from other simulations and agree well with ratios inferred from terrestrial samples.

Reedy, R. C.; Nishiizumi, K.; Arnold, J. R.; Lal, D.

353

Toward prompt gamma spectrometry for monitoring boron distributions during extra corporal treatment of liver metastases by boron neutron capture therapy: a Monte Carlo simulation study.  

PubMed

A Monte Carlo calculation was carried out for boron neutron capture therapy (BNCT) of extra corporal liver phantom. The present paper describes the basis for a subsequent clinical application of the prompt gamma spectroscopy set-up aimed at in vivo monitoring of boron distribution. MCNP code was used first to validate the homogeneity in thermal neutron field in the liver phantom and simulate the gamma ray detection system (collimator and detector) in the treatment room. The gamma ray of 478 keV emitted by boron in small specific region can be detected and a mathematical formalism was used for the tomography image reconstruction. PMID:19394243

Khelifi, R; Nievaart, V A; Bode, P; Moss, R L; Krijger, G C

2009-04-02

354

In Situ g-PHA Measurements of the 285-3H Cooling Tower Components  

SciTech Connect

The Analytical Development Section of Savannah River Technology Center was requested by the Facility Disposition Division to conduct in-situ gamma-ray pulse height analysis measurements to provide input toward the decision to unconditionally release the 285-3H cooling tower.

Salaymeh, S.R.

2001-05-23

355

Verification of the Pu content, isotopic composition and age of plutonium in Pu--Be neutron sources by gamma-spectrometry  

Microsoft Academic Search

A non-destructive, gamma-spectrometric method for verifying the plutonium content of Pu-Be neutron sources has been developed. It is also shown that the isotopic composition and the age of plutonium (Pu) can be determined in the intensive neutron field of these sources by the ``Multi-Group Analysis'' method. Gamma spectra were taken in the far-field of the sample, which was assumed to

Cong Tam Nguyen

2006-01-01

356

Distribution of natural and anthropogenic radionuclides in soil and beach sand samples of Kalpakkam (India) using hyper pure germanium (HPGe) gamma ray spectrometry  

Microsoft Academic Search

Pre-operational survey at Kalpakkam coast, indicated elevated gamma background radiation levels in the range of 100–4000nGyh?1 over the large tracts of the coastal sands due to the presence of pockets of monazite mineral in beach sands. In view of the prevalence of monazite, a systematic gamma spectrometric study of distribution of natural radionuclides in soil and beach sand samples collected

V Kannan; M. P Rajan; M. A. R Iyengar; R Ramesh

2002-01-01

357

Coincidence method for the analysis of minor elements in steel by deuteron-induced prompt \\/gamma-ray spectrometry (d-PIGE)  

Microsoft Academic Search

The sensitivities of minor elements analysis in a standard steel sample irradiated with 5 MeV deuterons have been determined by the regular deuteron-induced \\/gamma-ray emission (d-PIGE) method and with the selection of the (d,n) reaction channel by measuring \\/gamma-n coincidences. This approach has resulted in a significant improvement of the sensitivity of the analysis. A comparative study with the published

A. Ene; T. Badica; A. Olariu; I. V. Popescu; C. Besliu

2001-01-01

358

Poluchenie veroyatnostnykh otsenok nekotorykh priznakov obraza pika polnogo pogloshcheniya v mnogokanal'noj gamma-spektrometrii. (Determination of probabilistic evaluations of some pattern's signs of full absorption peak in multichannel gamma-ray spectrometry).  

National Technical Information Service (NTIS)

The expressions for calculation of probabilistic evaluations of full absorption peak (FAP) pattern's some signs in experimental (gamma)-spectra are obtained. These signs are FAP maximum stability, displacement of FAP maximum, rejection of FAP pattern's fo...

M. V. Stets D. I. Sikora

1989-01-01

359

IN SITU MEASUREMENTS OF ELASTIC PROPERTIES  

Microsoft Academic Search

Calculated values for the in situ elastic constants of rigidity, bulk ; modulus, Young's modulus, and Poisson's ratio from in situ measurements of ; compressional and shear wave velocities were obtained at two shot complexes in ; volcanic layered tuff under varying overburden conditions. Compressional and ; shear particle motions were selectively generated at the bottom of 100-ft-deep ; shot

Young; D. D. Jr

1961-01-01

360

IN SITU THERMAL DESORPTION OF COAL TAR  

Microsoft Academic Search

In Situ Thermal Desorption (ISTD) is a soil remediation process in which heat and vacuum are applied simultaneously to subsurface soils. Depending on the depth of treatment, an array of either thermal blankets or vacuum\\/heater wells is used. Produced vapors are treated with an air pollution control (APC) system to remove residual contaminants that have not been destroyed in situ.

Kirk S. Hansen; Denis M. Conley; Harold J. Vinegar; John M. Coles; James L. Menotti; George L. Stegemeier

361

ENGINEERING BULLETIN: IN SITU STEAM EXTRACTION TREATMENT  

EPA Science Inventory

In situ steam extraction removes volatile and semivolatile hazardous contaminants from soil and groundwater without excavation of the hazardous waste. Waste constituents are removed in situ by the technology and are not actually treated. The use of steam enhances the stripping of...

362

Matrix effects in the activity measurement of environmental samples—implementation of specific corrections in a gamma-ray spectrometry analysis program  

Microsoft Academic Search

Based on Monte Carlo simulations, a fast and accurate algorithm for the evaluation of the self-attenuation effects in ?-rays spectrometry has been developed. Using standard compositions for typical environmental samples (but allowing for density variations), an efficient procedure to compute on-line the self-attenuation corrections has been implemented in a dedicated ?-ray analysis program (Environmental Radioactivity Laboratory, Bucharest).

O. Sima; C. Dovlete

1997-01-01

363

In situ bioremediation in Europe  

SciTech Connect

Site remediation activity in Europe is increasing, even if not at the forced pace of the US. Although there is a better understanding of the benefits of bioremediation than of other approaches, especially about in situ bioremediation of contaminated soils, relatively few projects have been carried out full-scale in Europe or in the US. Some engineering companies and large industrial companies in Europe are investigating bioremediation and biotreatment technologies, in some cases to solve their internal waste problems. Technologies related to the application of microorganisms to the soil, release of nutrients into the soil, and enhancement of microbial decontamination are being tested through various additives such as surfactants, ion exchange resins, limestone, or dolomite. New equipment has been developed for crushing and mixing or injecting and sparging the microorganisms, as have new reactor technologies (e.g., rotating aerator reactors, biometal sludge reactors, and special mobile containers for simultaneous storage, transportation, and biodegradation of contaminated soil). Some work has also been done with immobilized enzymes to support and restore enzymatic activities related to partial or total xenobiotic decontamination. Finally, some major programs funded by public and private institutions confirm that increasing numbers of firms have a working interest in bioremediation.

Porta, A. [Battelle Europe, Geneva (CH); Young, J.K.; Molton, P.M. [Pacific Northwest Lab., Richland, WA (US)

1993-06-01

364

A gamma–gamma coincidence spectrometric method for rapid characterization of uranium isotopic fingerprints  

Microsoft Academic Search

This paper reports on initial efforts for uranium isotopic analysis using gamma-rays and X-ray fluorescence coincidence. In\\u000a this study, a gamma–gamma coincidence spectrometry was developed. The spectrometry consists of two NaI(Tl) scintillators and\\u000a XIA LLC Digital Gamma Finder (DGF)\\/Pixie-4 software and card package. The developed spectrometry was optimized according to\\u000a the considerations of output count rate and gamma peak energy

Weihua ZhangJing; Jing Yi; Pawel Mekarski; Kurt Ungar; Barry Hauck; Gary H. Kramer

2011-01-01

365

Development activities of a CdTe/CdZnTe pixel detector for gamma-ray spectrometry with imaging and polarimetry capability in astrophysics  

NASA Astrophysics Data System (ADS)

In the last few years we have been working on feasibility studies of future instruments in the gamma-ray range, from several keV up to a few MeV, in collaboration with other research institutes. High sensitivities are essential to perform detailed studies of cosmic explosions and cosmic accelerators, e.g., Supernovae, Classical Novae, Supernova Remnants (SNRs), Gamma-Ray Bursts (GRBs), Pulsars, Active Galactic Nuclei (AGN).Cadmium Telluride (CdTe) and Cadmium Zinc Telluride (CdZnTe) are very attractive materials for gamma-ray detection, since they have already demonstrated their great performance onboard current space missions, such as IBIS/INTEGRAL and BAT/SWIFT, and future projects like ASIM onboard the ISS. However, the energy coverage of these instruments is limited up to a few hundred keV, and there has not been yet a dedicated instrument for polarimetry.Our research and development activities aim to study a gamma-ray imaging spectrometer in the MeV range based on CdTe detectors, suited either for the focal plane of a focusing mission or as a calorimeter for a Compton camera. In addition, our undergoing detector design is proposed as the baseline for the payload of a balloon-borne experiment dedicated to hard X- and soft gamma-ray polarimetry, currently under study and called C?SP (CZT ?-Spectrometer Polarimeter). Other research institutes such as INAF-IASF, DTU Space, LIP, INEM/CNR, CEA, are involved in this proposal. We will report on the main features of the prototype we are developing at the Institute of Space Sciences, a gamma-ray detector with imaging and polarimetry capabilities in order to fulfil the combined requirement of high detection efficiency with good spatial and energy resolution driven by the science.

Gálvez, J. L.; Hernanz, M.; Álvarez, J. M.; Álvarez, L.; La Torre, M.; Caroli, E.; Lozano, M.; Pellegrini, G.; Ullán, M.; Cabruja, E.; Martínez, R.; Chmeissani, M.; Puigdengoles, C.

2013-05-01

366

Real-time in-situ chemical sensing, sensor-based film thickness metrology, and process control in W-CVD process  

Microsoft Academic Search

A real-time in-situ sampling system has been implemented for chemical sensing in tungsten chemical vapor deposition process (W-CVD) using mass spectrometry. Sensor integration was realized to allow synchronous capture of equipment state signals and process signals (chemical information from mass spectrometry). Wafer state metrology from integrated mass spectrometry signals of different gaseous chemical species in the reaction was established with

Yiheng Xu

2000-01-01

367

Determination of fluorine by proton-induced gamma-ray emission (PIGE) spectrometry in igneous and metamorphic charnockitic rocks from Rogaland (S. W. Norway)  

Microsoft Academic Search

More than 200 specimens from different occurrences of the Rogaland igneous complex and surrounding granulite facies metamorphic rocks (S. W. Norway) have been analysed by a direct non-destructive proton induced gamma-ray emission (PIGE) technique. The fluorine contents vary from

I. Roelandts; G. Robaye; G. Weber; J. M. Delbrouck; J. C. Duchesne

1987-01-01

368

Investigation of Photon Spectra and Contributions to Air Kerma Rates in the Environment near Nuclear Facilities using Portable Germanium Gamma Spectrometry  

Microsoft Academic Search

Environmental gamma ray spectra may be contributed by a number of photon sources of different energies. First, there is the contribution due to natural background: photons derived from cosmic rays present a continuum of energies but the primordial radionuclides and their decay chains (mainly 232 Th, 238 U and 40 K) produce a number of peaks at characteristic energies. 137Cs

G J Hunt

369

Optimization of the gamma spectrometry system at SAL with the use of large NaI(Tl) annulus in the anticoincidence mode for compton scattered radiation suppression.  

National Technical Information Service (NTIS)

A gamma-ray spectrometer designed for the simultaneous acquisition of normal, coincidence and anticoincidence spectra was extensively tested. The spectrometer consists of 3 detectors: a HPGe coaxial of 42% efficiency, NaI(Tl) annulus 254 mm length and 254...

J. Kierzek J. Parus

1997-01-01

370

In situ bioremediation using horizontal wells  

SciTech Connect

In Situ Bioremediation (ISB), which is the term used in this report for Gaseous Nutrient Injection for In Situ Bioremediation, remediates soils and ground water contaminated with volatile organic compounds (VOCs) both above and below the water table. ISB involves injection of air and nutrients (sparging and biostimulation) into the ground water and vacuum extraction to remove .VOCs from the vadose zone concomitant with biodegradation of VOCs. The innovation is in the combination of 3 emerging technologies, air stripping, horizontal wells, and bioremediation via gaseous nutrient injection with a baseline technology, soil vapor extraction, to produce a more efficient in situ remediation system.

NONE

1995-04-01

371

30 CFR 785.22 - In situ processing activities.  

Code of Federal Regulations, 2010 CFR

...2010-07-01 2010-07-01 false In situ processing activities. 785.22...CATEGORIES OF MINING § 785.22 In situ processing activities. (a...and reclamation operations utilizing in situ processing activities....

2010-07-01

372

30 CFR 828.11 - In situ processing: Performance standards.  

Code of Federal Regulations, 2010 CFR

... 3 2010-07-01 2010-07-01 false In situ processing: Performance standards. 828.11...SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-IN SITU PROCESSING § 828.11 In situ processing: Performance standards. (a)...

2010-07-01

373

30 CFR 828.11 - In situ processing: Performance standards.  

Code of Federal Regulations, 2010 CFR

... 3 2009-07-01 2009-07-01 false In situ processing: Performance standards. 828.11...SPECIAL PERMANENT PROGRAM PERFORMANCE STANDARDS-IN SITU PROCESSING § 828.11 In situ processing: Performance standards. (a)...

2009-07-01

374

In situ measurements of Li isotopes in foraminifera  

NASA Astrophysics Data System (ADS)

In situ measurement of Li isotope ratios in foraminifera has been developed using a Cameca ims 1270 ion microprobe. In situ ?7Li analyses have been performed in biogenic calcite of planktonic foraminifera from various locations. Results show that for west Pacific mixed Globigerinoides and Globorotalia (22°S161°E), the isotopic variability between tests and within a single test, respectively, is not significantly greater than estimated analytical uncertainty (˜1.5‰). Mean ?7Li for several planktonic foraminifera tests corresponds to the seawater value, strongly suggesting negligible Li isotope fractionation relative to seawater, as previously inferred by Hall et al. (2005) using thermo-ionization mass spectrometer and multicollector-inductively coupled plasma-mass spectrometry techniques. Combined with scanning electron microscopy and ion microprobe imaging, micron-sized grains, enriched in lithium, silica and aluminum have been found in the foraminifera calcite matrix. A simple mixing model shows that 0.3-2 wt % of marine clays incorporated within the analyzed calcite would lower the foraminifera ?7Li value, by 3‰ to 10‰ relative to the isotopic composition of the pure calcite. By comparison, no such grains have been detected in corals. The presence of micron-sized silicate grains embedded within the foraminifera calcite is consistent with the Erez (2003) biomineralization model, involving calcite precipitation from seawater vacuoles. By contrast, coral calcium carbonate is instead precipitated from ions, which have been pumped or diffused through several membranes, impermeable to micrometric grains. Ion microprobe in situ ?7Li measurements in biogenic calcite present new methods for investigating both biomineralization processes and the past record of the ocean composition by exploring geochemical variations at a scale that is smaller in space and in time.

Vigier, Nathalie; Rollion-Bard, Claire; Spezzaferri, Silvia; Brunet, Fabrice

2007-01-01

375

Gum containing calcium fluoride reinforces enamel subsurface lesions in situ.  

PubMed

The aim of this study was to assess the effect of chewing gum containing phosphoryl oligosaccharides of calcium (POs-Ca) and a low concentration of fluoride (F) on the hardness of enamel subsurface lesions, utilizing a double-blind, randomized, and controlled in situ model. Fifteen individuals wore removable lingual appliances with 3 bovine-enamel insets containing subsurface demineralized lesions. Three times a day for 14 days, they chewed one of the 3 chewing gums (placebo, POs-Ca, POs-Ca+F). After the treatment period, cross-sectional mineral content, nanoindentation hardness, and fluoride ion mapping by time-of-flight secondary ion mass spectrometry (TOF-SIMS) were evaluated. Although there were no statistical differences in overall mineral content and hardness recovery rates between POs-Ca and POs-Ca+F subsurface lesions (p > 0.05), nanoindentation at 1-?m distance increments from the surface showed statistical differences in hardness recovery rate between POs-Ca and POs-Ca+F in the superficial 20-?m region (p < 0.05). Fluoride mapping revealed distribution of the ion up to 20 ?m from the surface in the POs-Ca+F group. Nanoindentation and TOF-SIMS results highlighted the benefits of bioavailability of fluoride ion on reinforcement of the superficial zone of subsurface lesions in situ (NCT01377493). PMID:22337700

Kitasako, Y; Sadr, A; Hamba, H; Ikeda, M; Tagami, J

2012-02-15

376

An integrated microfluidic device for large-scale in situ click chemistry screening†  

PubMed Central

An integrated microfluidic device has been developed to perform 1024 in situ click chemistry reactions in parallel using the bovine carbonic anhydrous II (bCAII) click chemistry system as a proof-of-concept study and a rapid hit identification approach using SPE purification and electrospray-ionization mass spectrometry, multiple reaction monitoring (MRM) analysis, all of which improves the sensitivity and throughput of the downstream analysis.

Wang, Yanju; Lin, Wei-Yu; Liu, Kan; Lin, Rachel J.; Selke, Matthias; Kolb, Hartmuth C.; Zhang, Nangang; Zhao, Xing-Zhong; Phelps, Michael E.; Shen, Clifton K. F.

2010-01-01

377

On the possible in situ elemental analysis of small bodies with laser ablation TOF-MS  

Microsoft Academic Search

An analysis is presented of the potential application of laser ablation time-of-flight mass spectrometry (LA-TOF-MS) to the study of small bodies on in situ and sample return missions. LA-TOF-MS provides the significant advantages of high-quality, low-ambiguity data, no requirement of sample contact or preparation, rapid analysis, and local probe capability. The ability to address particular scientific goals on a given

W. B. Brinckerhoff

2005-01-01

378

The current performance of the in situ 14C extraction line at ETH  

Microsoft Academic Search

We present the new 14C extraction line at ETH Zürich. This system is designed to extract in situ-produced cosmogenic 14C from terrestrial quartz samples, and to obtain pure CO2 gas for analysis with a gas ion source Accelerator Mass Spectrometry (AMS) system. Samples are degassed at 1550–1600°C without the use of a fluxing agent. Gas purification is achieved by a

Kristina Hippe; Florian Kober; Heinrich Baur; Matthias Ruff; Lukas Wacker; Rainer Wieler

2009-01-01

379

A Plant Peptide Encoded by CLV3 Identified by in Situ MALDI-TOF MS Analysis  

Microsoft Academic Search

The Arabidopsis CLAVATA3 (CLV3) gene encodes a stem cell-specific protein presumed to be a precursor of a secreted peptide hormone. Matrix-assisted laser desorption\\/ionization-time-of-flight mass spectrometry (MALDI-TOF MS) applied to in situ Arabidopsis tissues determined the structure of a modified 12-amino acid peptide (MCLV3), which was derived from a conserved motif in the CLV3 sequence. Synthetic MCLV3 induced shoot and root

Tatsuhiko Kondo; Shinichiro Sawa; Atsuko Kinoshita; Satoko Mizuno; Tatsuo Kakimoto; Hiroo Fukuda; Youji Sakagami

2006-01-01

380

Gamma-gamma colliders  

SciTech Connect

Gamma-gamma colliders make intense beams of gamma rays and have them collide so as to make elementary particles. The authors show, in this article, that constructing a gamma-gamma collider as an add-on to an electron-positron linear collider is possible with present technology and that it does not require much additional cost. Furthermore, they show that the resulting capability is very interesting from a particle physics point of view. An overview of a linear collider, with a second interaction region devoted to {gamma}{gamma} collisions is shown.

Kim, K.J.; Sessler, A.

1996-06-01

381

Molecular Epidemiology of Breast Carcinoma In Situ.  

National Technical Information Service (NTIS)

This is a molecular epidemiologic case-control study of breast carcinoma in situ in Los Angeles County designed to address issues related to the cause and progression of breast CIS by determining epidemiologic risk factors, characterizing selected molecul...

M. F. Press

1997-01-01

382

Molecular Epidemiology of Breast Carcinoma In Situ.  

National Technical Information Service (NTIS)

This is a molecular epidemiologic case-control study of breast carcinoma in situ in Los Angeles County designed to address issues related to the cause and progression of breast CIS by determining epidemiologic risk factors, characterizing selected molecul...

M. Press

1999-01-01

383

Molecular Epidemiology of Breast Carcinoma in Situ.  

National Technical Information Service (NTIS)

This is a molecular epidemiologic case-control study of breast carcinoma in situ in Los Angeles County designed to address issues related to the cause and progression of breast CIS by determining epidemiologic risk factors, characterizing selected molecul...

M. F. Press

1998-01-01

384

Molecular cytogenetics using fluorescence in situ hybridization.  

National Technical Information Service (NTIS)

Fluorescence in situ hybridization (FISH) with chromosome-specific probes enables several new areas of cytogenetic investigation by allowing visual determination of the presence and normality of specific genetic sequences in single metaphase or interphase...

J. W. Gray W. L. Kuo J. Lucas D. Pinkel H. U. Weier

1990-01-01

385

ENHANCED BIODEGRADATION THROUGH IN-SITU AERATION  

EPA Science Inventory

This presentation provided an overview of enhanced aerobic bioremediation using in-situ aeration or venting. The following topics were covered: (1) Basic discussion on biodegradation and respiration testing; (2) Basic discussion on volatilization, rate-limited mass transport, an...

386

In situ remediation of the geoenvironment  

Microsoft Academic Search

This document contains the Proceedings of the Conference on In-Situ Remediation of the Geoenvironment held in Minneapolis, Minnesota, October 5-8, 1997. The progress in the development and implementation of techniques for the remediation of contaminated soils and ground water has been and continues to be rapid. These proceedings focus on the in-situ remediation of the geoenvironment and are a result

1997-01-01

387

Use of the 1001 keV peak of 234mPa daughter of 238U in measurement of uranium concentration by HPGe gamma-ray spectrometry  

Microsoft Academic Search

For the direct gamma-ray spectrometric measurements of uranium concentrations in the samples, the use of 1001keV peak of 234mPa, second daughter of 238U is emphasized. This “clean” peak is well resolved by HPGe detectors and gives accurate indication of uranium concentration in the samples without any self-absorption correction. The 1001keV peak of 234mPa in the 238U chain is selected because

H Yücel; M. A Çetiner; H Demirel

1998-01-01

388

Rapid chemotaxonomy of pathogenic bacteria using in situ thermal hydrolysis and methylation as a sample preparation step coupled with a field–portable membrane-inlet quadrupole ion trap mass spectrometer 1 1 Dedicated to J.F.J. Todd and R.E. March in recognition of their original contributions to quadrupole ion trap mass spectrometry  

Microsoft Academic Search

A field-portable, pyrolysis membrane-inlet quadrupole ion trap mass spectrometer has been used to characterize four pathogenic bacteria (Bacillus anthracis, Brucella melitensis, Yersinia pestis, and Francisella tularensis). Moreover, a variety of strains were included, prepared under various growth conditions and a range of growth stages. In these analyses, an in situ thermal hydrolysis-methylation procedure was used during pyrolysis with the reagent

Alan D. Hendricker; Christy Abbas-Hawks; Franco Basile; Kent J. Voorhees; Ted L. Hadfield

1999-01-01

389

THE GAMMA-RAY SPECTROMETRY OF FISSION PRODUCTS. VI. THE CALCULATED AND EXPERIMENTAL GAMMA-RAY SCINTILLATION SPECTRA OF U²³⁵ FISSION PRODUCTS WITH CYLINDRICAL NaI (Tl) CRYSTALS  

Microsoft Academic Search

The calculation of scintillation spectra for the broad parallel gamma ; rays emitted from U²³⁵ fission products incident on a right circular ; cylindrical NaI (Tl) crystals is presented. Typical scintillation spectra from ; fission products are presented. The parameters of the spectra were tabulated as ; functions of time after fission. The calculated spectra with a 1.75-in.-dia x 1

Hattori

1961-01-01

390

Set-up of a passive Bonner sphere system for neutron spectrometry at mixed fields with predominant photon component based on activation detector.  

PubMed

A passive Bonner sphere system (BSS), based on thermal neutron activation detectors, was developed to perform neutron spectrometry in pulsed and very intense (n-gamma) fields with predominant photon component, as those produced by high energy (>10 MV) medical linear electron accelerators. In this paper, a description of the new system is presented together with an experimental characterisation of a portable Sodium Iodide (NaI) detector and a fixed high-purity Germanium one, both used to measure the induced gamma-activity of the activated materials, respectively, in situ and in the laboratory. The choice of the activated materials is justified according to pre-established practical considerations and physical criteria. The response functions of the entire passive BSS were calculated using the MCNPX code. A preliminary experimental validation with a bare (252)Cf source is given as well. PMID:17513860

Amgarou, K; Lacoste, V; Muller, H; Fernández, F

2007-05-18

391

Field gamma dose-rate assessment in natural sedimentary contexts using LaBr3(Ce) and NaI(Tl) probes: a comparison between the "threshold" and "windows" techniques.  

PubMed

Results are presented for a series of replicate in situ gamma spectrometry measurements (n=20) made in natural sedimentary contexts using LaBr3(Ce) and NaI(Tl) probes. For both types of detectors, gamma dose rates were calculated using the "threshold" technique (Murray et al., 1978), and compared with results obtained previously by Arnold et al. (2012) using the "windows" technique (Aitken, 1985). Our results show that gamma dose rates obtained using these two techniques are consistent at 1? for a given probe, and that the threshold technique yields reproducible results for the LaBr3(Ce) and NaI(Tl) probes. In comparison with the energy windows approach, the threshold approach offers an improvement in the precision with which gamma dose rates can be determined using the LaBr3(Ce) probe. The potential of an alternative threshold approach (the "energy threshold" approach of Guérin and Mercier, 2011) was also tested for both probe types, and the resultant gamma dose rates were found to be in agreement with those obtained using the standard threshold and energy windows techniques. Our results provide new insights into methods and instrumentation used for assessing in situ gamma dose rates in Electron Spin Resonance (ESR) and Luminescence dating. We conclude that LaBr3(Ce) probes can reliably be used for portable gamma dosimetry in low level activity sedimentary environments (500-1500?Gy/a) when using the threshold approach, provided that their non-negligible internal background activities (equivalent to ?758?Gy/a for our probe) are accurately assessed and subtracted from gamma ray spectra measured in the field. Our results also suggest that there may be some minor merit in applying an internal background-subtraction procedure to NaI(Tl) gamma ray spectra when using the threshold technique, in spite of the lower intrinsic activities of NaI(Tl) detectors. PMID:23353090

Duval, M; Arnold, L J

2012-12-20

392

Simulations of terrestrial in-situ cosmogenic-nuclide production  

SciTech Connect

Targets of silicon and silicon dioxide were irradiated with spallation neutrons to simulate the production of long-lived radionuclides in the surface of the earth. Gamma-ray spectroscopy was used to measure {sup 7}Be and {sup 22}Na, and accelerator mass spectrometry was used to measure {sup 10}Be, {sup 14}C, and {sup 26}Al. The measured ratios of these nuclides are compared with calculated ratios and with ratios from other simulations and agree well with ratios inferred from terrestrial samples.

Reedy, R.C. [Los Alamos National Lab., NM (United States); Nishiizumi, K.; Arnold, J.R. [California Univ., San Diego, La Jolla, CA (United States). Dept. of Chemistry; Lal, D. [Scripps Institution of Oceanography, La Jolla, CA (United States); Englert, P.A.J. [San Jose State Univ., CA (United States). Nuclear Science Facility; Klein, J.; Middleton, R. [Pennsylvania Univ., Philadelphia, PA (United States). Dept. of Physics; Jull, A.J.T.; Donahue, D.J. [Univ. of Arizona, Tucson, AZ (United States). NSF Accelerator Facility for Radioisotope Analysis

1993-12-31

393

Radiation resistance of sequencing chips for in situ life detection.  

PubMed

Life beyond Earth may be based on RNA or DNA if such life is related to life on Earth through shared ancestry due to meteoritic exchange, such as may be the case for Mars, or if delivery of similar building blocks to habitable environments has biased the evolution of life toward utilizing nucleic acids. In this case, in situ sequencing is a powerful approach to identify and characterize such life without the limitations or expense of returning samples to Earth, and can monitor forward contamination. A new semiconductor sequencing technology based on sensing hydrogen ions released during nucleotide incorporation can enable massively parallel sequencing in a small, robust, optics-free CMOS chip format. We demonstrate that these sequencing chips survive several analogues of space radiation at doses consistent with a 2-year Mars mission, including protons with solar particle event-distributed energy levels and 1 GeV oxygen and iron ions. We find no measurable impact of irradiation at 1 and 5 Gy doses on sequencing quality nor on low-level hardware characteristics. Further testing is required to study the impacts of soft errors as well as to characterize performance under neutron and gamma irradiation and at higher doses, which would be expected during operation in environments with significant trapped energetic particles such as during a mission to Europa. Our results support future efforts to use in situ sequencing to test theories of panspermia and/or whether life has a common chemical basis. PMID:23734755

Carr, Christopher E; Rowedder, Holli; Lui, Clarissa S; Zlatkovsky, Ilya; Papalias, Chris W; Bolander, Jarie; Myers, Jason W; Bustillo, James; Rothberg, Jonathan M; Zuber, Maria T; Ruvkun, Gary

2013-06-04

394

Using Gamma Spectrometry to Determine U, Th, and K Signatures in Cap Carbonates of the Death Valley Region and Their Relation to Other Carbonates  

NASA Astrophysics Data System (ADS)

We collected spectral gamma data (K, U, Th) and measured sections in cap carbonates (Noonday dolomite) and cap-like carbonates (Beck Spring dolomite) of the Death Valley region in order to explore elemental changes in the post-snowball oceans. The Snowball Earth theory of Hoffman et al. (1998) proposes dramatic post-glacial chemical weathering as large concentrations of carbon were removed from the atmosphere. This would result in a large input of terrigenous material; hence, we expect that carbonates formed under these conditions would demonstrate elevated K, U, Th levels in comparison to carbonates formed under more typical conditions. However, based on our preliminary findings, cap carbonates of the Noonday dolomite and cap-like carbonates of the Beck Spring dolomite have values (0-1% for K, 0.2-6.0 ppm for U, and 0.6-6.9 ppm for Th) that fall within the published range for those measured in carbonates (presumably non-cap or cap-like carbonates). Possible explanations for this include: (a) dilution of any terrigeneous signal by the vast amount of carbonate precipitating in the oceans, or (b) any biological activity that might have an influence on chemical processes in the ocean. A preliminary comparison of our spectral gamma data measured in the Noonday dolomite with published ? 13C data from the same section indicate similar trends in both proxies, namely, a very gradual decrease in values through the majority of the section (Lower Noonday) followed by a more noticeable increase in values in the upper part of the section (Upper Noonday). Further work will be necessary to determine the significance of this possible correlation. Additionally, planned analysis of hand specimens using a high-resolution gamma spectrometer should provide more details about the composition of cap-carbonates and provide further information about the conditions under which they were formed.

Hannon, M.; Lindberg, J.; Barrie, C.; Johnson, T.; Donatelle, A.; Goeden, J.; Holter, S.; Hickson, T.; Theissen, K.; Lamb, M.

2004-05-01

395

Improvement in the determination of 238U, 228-234Th, 226-228Ra, 210Pb, and 7Be by gamma spectrometry on evaporated fresh water samples.  

PubMed

For the U-Th series radionuclides investigation in natural freshwater, a simple, fast, and not laboratory intensive method which consists of evaporating the water samples to dryness in the presence of carriers is presented. The small volume of the residue (1-2 cm3) leads to a good efficiency for gamma counting and limits the self-absorption effect for the low energy gamma rays (less than 200 keV). The best efficiency is obtained with a well-type Ge detector. To determine the evaporation yields a river with a common uranium content, the Seine river (France), was selected. By using internal spikes and more conventional techniques of investigation, we demonstrate that the evaporation is quantitative for U, Th, Ra, Pb, and Be. The residue of a 3 L, standard superficial freshwater, evaporated sample was analyzed in a high efficiency, low background Ge detector, which leads to a sufficient precision for most environmental studies. The method has been applied to rain, river, and lake waters to study the impact of disused uranium mine water inputs on the 238U, 228-234Th, 226-228Ra, 210Pb, and 7Be river and lake contents in the U mining area of Limoges (France). PMID:14620828

Cazala, C; Reyss, J L; Decossas, J L; Royer, A

2003-11-01

396

In situ forming polymeric drug delivery systems.  

PubMed

In situ forming polymeric formulations are drug delivery systems that are in sol form before administration in the body, but once administered, undergo gelation in situ, to form a gel. The formation of gels depends on factors like temperature modulation, pH change, presence of ions and ultra violet irradiation, from which the drug gets released in a sustained and controlled manner. Various polymers that are used for the formulation of in situ gels include gellan gum, alginic acid, xyloglucan, pectin, chitosan, poly(DL-lactic acid), poly(DL-lactide-co-glycolide) and poly-caprolactone. The choice of solvents like water, dimethylsulphoxide, N-methyl pyrrolidone, triacetin and 2-pyrrolidone for these formulations depends on the solubility of polymer used. Mainly in situ gels are administered by oral, ocular, rectal, vaginal, injectable and intraperitoneal routes. The in situ gel forming polymeric formulations offer several advantages like sustained and prolonged action in comparison to conventional drug delivery systems. The article presents a detailed review of these types of polymeric systems, their evaluation, advancements and their commercial formulations. From a manufacturing point of view, the production of such devices is less complex and thus lowers the investment and manufacturing cost. PMID:20490289

Madan, M; Bajaj, A; Lewis, S; Udupa, N; Baig, J A

2009-05-01

397

The SMAP In Situ Soil Moisture Sensor Testbed: Comparing in situ sensors for satellite validation  

Technology Transfer Automated Retrieval System (TEKTRAN)

One of the most valuable tools in validating satellite based soil moisture estimates, such as those from the Soil Moisture Active Passive (SMAP) mission are large scale in situ networks. Global validation involves networks operated by many different organizations. Existing in situ soil moisture netw...

398

ADVANTAGES/DISADVANTAGES FOR ISCO METHODS IN-SITU FENTON OXIDATION IN-SITU PERMANGANATE OXIDATION  

EPA Science Inventory

The advantages and disadvantages of in-situ Fenton oxidation and in-situ permanganate oxidation will be presented. This presentation will provide a brief overview of each technology and a detailed analysis of the advantages and disadvantages of each technology. Included in the ...

399

Determination of disulfide bond assignment of human vitamin K-dependent gamma-glutamyl carboxylase by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry.  

PubMed

Vitamin K-dependent gamma-glutamyl carboxylase is a 758 amino acid integral membrane glycoprotein that catalyzes the post-translational conversion of certain protein glutamate residues to gamma-carboxyglutamate. Carboxylase has ten cysteine residues, but their form (sulfhydryl or disulfide) is largely unknown. Pudota et al. in Pudota, B. N., Miyagi, M., Hallgren, K. W., West, K. A., Crabb, J. W., Misono, K. S., and Berkner, K. L. (2000) Proc. Natl. Acad. Sci. U. S. A. 97, 13033-13038 reported that Cys-99 and Cys-450 are the carboxylase active site residues. We determined the form of all cysteines in carboxylase using in-gel protease digestion and matrix-assisted laser desorption/ionization mass spectrometry. The spectrum of non-reduced, trypsin-digested carboxylase revealed a peak at m/z 1991.9. Only this peak disappeared in the spectrum of the reduced sample. This peak's m/z is consistent with the mass of peptide 92-100 (Cys-99) disulfide-linked with peptide 446-453 (Cys-450). To confirm its identity, the m/z 1991.9 peak was isolated by a timed ion selector as the precursor ion for further MS analysis. The fragmentation pattern exhibited two groups of triplet ions characteristic of the symmetric and asymmetric cleavage of disulfide-linked tryptic peptides containing Cys-99 and Cys-450. Mutation of either Cys-99 or Cys-450 caused loss of enzymatic activity. We created a carboxylase variant with both C598A and C700A, leaving Cys-450 as the only remaining cysteine residue in the 60-kDa fragment created by limited trypsin digestion. Analysis of this fully active mutant enzyme showed a 30- and the 60-kDa fragment were joined under non-reducing conditions, thus confirming Cys-450 participates in a disulfide bond. Our results indicate that Cys-99 and Cys-450 form the only disulfide bond in carboxylase. PMID:12963724

Tie, Jian-Ke; Mutucumarana, Vasantha P; Straight, David L; Carrick, Kevin L; Pope, R Marshall; Stafford, Darrel W

2003-09-08

400

Florid lobular carcinoma in situ: molecular profiling and comparison to classic lobular carcinoma in situ and pleomorphic lobular carcinoma in situ.  

PubMed

We evaluated genomic alterations and biomarker expression in 20 florid lobular carcinomas in situ using array-based comparative genomic hybridization and immunohistochemical analysis. The genetic characteristics of florid lobular carcinoma in situ were compared with 20 classic lobular carcinomas in situ and 21 pleomorphic lobular carcinomas in situ (which included 8 apocrine variants), from our previously published data performed on a similar array-based comparative genomic hybridization platform. All 20 florid lobular carcinoma in situ cases were E-cadherin negative, and 92% were positive for estrogen receptor. Cyclin D1 expression correlated significantly negatively with estrogen receptor expression and was higher in cases with cyclin D1 (CCND1) gene amplification. Compared with classic lobular carcinoma in situ, florid lobular carcinoma in situ displayed significantly more fraction genome alteration (mean, 0.109 versus 0.072; P=.007), fraction genome loss (mean, 0.06 versus 0.03; P=.007), numbers of breakpoints (mean, 11.55 versus 6.95; P=.002), numbers of chromosome with breakpoints (mean, 5.85 versus 3.8; P=.004), and higher numbers of amplifications (mean, 2.10 versus 0.25; P=.03). Interestingly, florid lobular carcinoma in situ had the same genetic complexity as apocrine pleomorphic lobular carcinoma in situ. Our study demonstrated that florid lobular carcinoma in situ shares the cytologic features, E-cadherin loss, and the lobular genetic signature of 1q gain and 16q loss found in classic lobular carcinoma in situ. However, this variant demonstrates more genomic alterations than classic lobular carcinoma in situ and shares the same genetic complexity as apocrine pleomorphic lobular carcinoma in situ. Our data support the conclusion that florid lobular carcinoma in situ is genetically more advanced compared with the indolent phenotype of classic lobular carcinoma in situ. This may explain the greater frequency of concurrent invasive carcinoma in florid lobular carcinoma in situ compared with classic lobular carcinoma in situ. PMID:23809857

Shin, Sandra J; Lal, Aseem; De Vries, Sandy; Suzuki, Junko; Roy, Ritu; Hwang, E Shelley; Schnitt, Stuart J; Waldman, Frederic M; Chen, Yunn-Yi

2013-06-25

401

In-situ optical photoreflectance during MOCVD  

SciTech Connect

This report summarizes the development of in situ optical photoreflectance as a tool for measuring impurity concentrations in compound semiconductors. The authors have successfully explored the use of photoreflectance as an in situ tool for measuring n-type doping levels in metal-organic chemical vapor deposition (MOCVD) grown GaAs materials. The technique measures phase and frequency shifts in Franz-Keldysh oscillations measured on uniformly doped thin films. Doping concentrations from 5 {times} 10{sup 16} to 1 {times} 10{sup 18} can be measured at temperatures below 130 C. A method has been developed to include photoreflectance as the last step in the pre-growth in situ calibration procedure for MOCVD thin film structures. This combined capability now enables one to rapidly and accurately determine growth rates, chemical composition, and doping levels necessary to generate a recipe to fabricate complex optoelectronic compound semiconductor devices.

Breiland, W.G.; Hammons, B.E.; Hou, H.Q.; Mei, X.B. [Sandia National Labs., Albuquerque, NM (United States). Chemical Processing Sciences Dept.

1998-01-01

402

Materials Phenomena Revealed by In Situ Tribometry  

NASA Astrophysics Data System (ADS)

In situ tribometry, the study of real-time friction and wear processes occurring at "buried" sliding interfaces, was used to examine fundamental changes to structure and chemistry of solid lubricant and hard coatings. In situ techniques of optical microscopy and Raman spectroscopy were used to observe interfacial sliding dynamics and identify near-surface structural/chemical changes, respectively. Third-body physical and chemical processes, such as thickening, thinning, loss of transfer films, generation of wear debris, and sliding-induced chemical changes, were identified for sapphire sliding against Ti-Si-C, nanocrystalline diamond (NCD), and titanium- and tungsten-doped diamond-like carbon (DLC) coatings. These processes observed by in situ methods were also used to explain why friction and wear behavior changed with coating composition, properties or test conditions.

Chromik, R. R.; Strauss, H. W.; Scharf, T. W.

2012-01-01

403

In Situ Vitrification Treatability Study Work Plan  

SciTech Connect

The Buried Waste Program was established in October, 1987 to accelerate the studies needed to develop a recommended long-term management plan for the buried mixed waste at the Radioactive Waste Management Complex at the Idaho National Engineering Laboratory. The In Situ Vitrification Project is being conducted in a Comprehensive Environmental Response, Compensation, and Liability Act Feasibility Study format to identify methods for the long-term management of the mixed waste buried. This In Situ Vitrification Treatability Study Work Plan gives a brief description of the site, work breakdown structure, and project organization: the in situ vitrification technology; the purpose of the tests and demonstrations; and the equipment and materials required for the tests and demonstration. 5 refs., 6 figs., 3 tabs.

Charboneau, B.L.; Landon, J.L.

1989-03-01

404

In situ study of the 41Ar plume released from the Ignalina NPP  

NASA Astrophysics Data System (ADS)

The 41Ar gamma ray radiation was registered using the in situ method in the vicinity of the Ignalina nuclear power plant (NPP). The sum of gamma rays, that are reaching the HPGe detector, situated along the wind direction, from a number of plume segments and which are registered in the energy range of about 1.29 MeV, is calculated. An independent technological regime of the operating reactor method of the determination of the 41Ar emission rate from NPP stack is introduced.

Jasiulionis, Rimvydas; Vy?inas, Linas; Rožkov, Andrej

2008-12-01

405

Potential of natural gamma-ray spectrometry for mapping and environmental monitoring of black-sand beach deposits on the northern coast of Sinai, Egypt.  

PubMed

The concentrations and distributions of naturally occurring radioactive materials were studied with the aim of detecting and mapping radioactive anomalies as well as monitoring the environment for black-sand beach deposits in Northern Sinai, Egypt. For this purpose, ground gamma-ray spectrometric surveys were conducted using a portable GS-512 spectrometer, with an NaI (Tl) detector, on an area 77.5 km(2) in surface area located between the cities of Rafah and Elareish on the Mediterranean Sea coast. The results revealed that the black-sand beach deposits could be differentiated according to their total-count (TC) radioactivity into five normally distributed interpreted radiometric lithologic (IRL) units denoted by U1, U2, U3, U4 and U5. The computed characteristic TC radiometric statistics of these five IRL units range from 4.67  to 9.96 Ur for their individual arithmetic means. The computed arithmetic means for the three radioelements K, eU and eTh reach 0.46 %, 2.25 and 6.17 ppm, respectively for the whole study area. Monitoring the environmental effects of radioelement concentrations on the study area showed that the mean natural equivalent radiation dose rate from the terrestrial gamma-radiation of the whole area attains 0.33 mSv y(-1). This average value remains on the safe side and within the maximum permissible safe radiation dose (<1.0 mSv y(-1)) without harm to the individual, except at three scattered points reaching more than these values. Some of the local inhabitants in the region sometimes use black sands as a building material. Consequently, they are not recommended for use as building materials, because the inhabitants will, then, receive a relatively high radioactive dose generated mainly by monazite and zircon minerals, two of the main constituents of black sands. PMID:22869819

Aboelkhair, Hatem; Zaaeimah, Mostafa

2012-08-05

406

In-situ vitrification of waste materials  

DOEpatents

A method for the in-situ vitrification of waste materials in a disposable can that includes an inner container and an outer container is disclosed. The method includes the steps of adding frit and waste materials to the inner container, removing any excess water, heating the inner container such that the frit and waste materials melt and vitrify after cooling, while maintaining the outer container at a significantly lower temperature than the inner container. The disposable can is then cooled to ambient temperatures and stored. A device for the in-situ vitrification of waste material in a disposable can is also disclosed.

Powell, James R. (Shoreham, NY); Reich, Morris (Kew Gardens Hills, NY); Barletta, Robert (Wading River, NY)

1997-11-14

407

In situ mineralogy and permeability logs from downhole measurements: Application to a case study in chlorite-coated sandstones  

Microsoft Academic Search

Well-logging techniques provide continuous profiles of various in situ physical properties like the bulk density, the photoelectric effect, and the natural gamma radioactivity of geological formations. Our purpose is to use this information to determine a continuous profile of the mineralogy with depth. The well-log derived mineralogy is then combined with a petrophysical model to infer continuous permeability and saturation

A. Rabaute; A. Revil; E. Brosse

2003-01-01

408

Exposure of the lysine in the gamma chain dodecapeptide of human fibrinogen is not enhanced by adsorption to poly(ethylene terephthalate) as measured by biotinylation and mass spectrometry  

PubMed Central

Conformational changes in adsorbed fibrinogen may enhance the exposure of platelet adhesive sites that are inaccessible in solution. To test this hypothesis, mass spectrometric methods were developed to quantify chemical modification of lysine residues following adsorption of fibrinogen to biomaterials. The quantitative method used an internal standard consisting of isotope-labeled fibrinogen secreted by human HepG2 cells in culture. Lysine residues in the internal standard were partially reacted with NHS-biotin. For the experimental samples, normal human fibrinogen was adsorbed to polyethylene terephthalate (PET) particles. The adsorbed fibrinogen was reacted with NHS-biotin and then eluted from the particles. Constant amounts of internal standard were added to sample fibrinogen and analyzed by liquid chromatography/tandem mass spectrometry. Biotinylation of the lysine residue in the platelet-adhesive gamma chain dodecapeptide (GCDP) was quantified by comparison to the internal standard. Approximately 80% of the GCDP peptides were biotinylated when fibrinogen was reacted with NHS-biotin in solution, or adsorbed onto PET. These results are generally consistent with previous antibody binding studies and suggest that other regions of fibrinogen may be crucial in promoting platelet adhesion to materials. The results do not directly address but are consistent with the hypothesis that only activated platelets adhere to adsorbed fibrinogen.

Ovod, Vitaliy; Scott, Evan A.; Flake, Megan M.; Parker, Stanley R.; Bateman, Randall J.; Elbert, Donald L.

2011-01-01

409

STEREO In-situ Data Analysis  

NASA Astrophysics Data System (ADS)

STEREO's IMPACT (In-situ Measurements of Particles and CME Transients) investigation provides the first opportunity for long duration, detailed observations of 1 AU magnetic field structures, plasma and suprathermal electrons, and energetic particles at points bracketing Earth's heliospheric location. The PLASTIC instrument takes plasma ion composition measurements completing STEREO's comprehensive in-situ perspective. Stereoscopic/3D information from the STEREO SECCHI imagers and SWAVES radio experiment make it possible to use both multipoint and quadrature studies to connect interplanetary Coronal Mass Ejections (ICME) and solar wind structures to CMEs and coronal holes observed at the Sun. The uniqueness of the STEREO mission requires novel data analysis tools and techniques to take advantage of the mission's full scientific potential. An interactive browser with the ability to create publication-quality plots has been developed which integrates STEREO's in-situ data with data from a variety of other missions including WIND and ACE. Also, an application program interface (API) is provided allowing users to create custom software that ties directly into STEREO's data set. The API allows for more advanced forms of data mining than currently available through most web-based data services. A variety of data access techniques and the development of cross-spacecraft data analysis tools allow the larger scientific community to combine STEREO's unique in-situ data with those of other missions, particularly the L1 missions, and, therefore, to maximize STEREO's scientific potential in gaining a greater understanding of the heliosphere.

Schroeder, P. C.; Luhmann, J. G.; Davis, A. J.; Russell, C. T.

2006-12-01

410

Excursion Control at in Situ Uranium Mines.  

National Technical Information Service (NTIS)

This paper summarizes excursions (uncontrolled movement of lixiviant beyond the ore zone) based on case histories of 8 in situ uranium mines (7 in Wyoming and 1 in Texas). These case histories were compiled from data provided by the US Nuclear Regulatory ...

W. P. Staub

1987-01-01

411

In situ recycling of urban deciduous litter  

Microsoft Academic Search

When 1, 2, 4 and 8 times the average annual litterfall was placed around trees in a shade tree evaluation plantation, earthworm populations increased with increasing application rate after 5 months. After 17 and 60 months there was no significant effect on earthworm populations. In situ recycling of leaf litter can increase earthworm populations in urban soils.

Steven R. Cothrel; John P. Vimmerstedt; David A. Kost

1997-01-01

412

Innovative technologies for in-situ remediation  

Microsoft Academic Search

LLNL is developing several innovative remediation technologies as long-term improvements to the current pump and treat approaches to cleaning up contaminated soils and groundwater. These technologies include dynamic underground stripping, in-situ microbial filters, and remediation using bremsstrahlung radiation. Concentrated underground organic contaminant plumes are one of the most prevalent groundwater contamination sources. The solvent or fuel can percolate deep into

R. Ragaini; R. Aines; R. Knapp; S. Matthews; J. Yow

1994-01-01

413

Avery Island: Dome Salt in Situ Test.  

National Technical Information Service (NTIS)

Objective of this in situ test is to provide quantitative data that can be used to determine whether or not bedded and domal salt will behave similarly in response to heating. The Avery Island (AI) heater test will provide a test case wherein a quantitati...

P. D. Fairchild G. H. Jenks

1978-01-01

414

IN SITU SOIL VAPOR EXTRACTION TREATMENT  

EPA Science Inventory

Soil vapor extraction (SVE) is designed to physically remove volatile compounds, generally from the vadose or unsaturated zone. t is an in situ process employing vapor extraction wells alone or in combination with air injection wells. acuum blowers supply the motive force, induci...

415

TECHNICAL REFERENCE DOCUMENT: IN SITU THERMAL TREATMENT  

EPA Science Inventory

This report will describe the state of practice and current capabilities of in-situ thermal treatment technologies. PLEASE NOTE: If peer review is needed, it will be conducted by the Army Corps of Engineers who is our partner in developing this report....

416

In situ Shear Strength Tester for Coal.  

National Technical Information Service (NTIS)

The objective of this research was to develop a device for rapid in situ measurement of rock shearing strength and to compare the shearing strength results with those obtained by other test methods. The rock borehole shear test (RBST) operates by expansio...

R. L. Handy L. E. Engle J. M. Pitt

1976-01-01

417

IN SITU MONITORING OF ENVIRONMENTAL GENOTOXINS  

EPA Science Inventory

Potential health hazard of a test site can be assessed by (1) epidemiological survey of the indigenous populations, (2) in situ monitoring by introducing test organisms into the environment, and (3) bringing environmental samples from the test site into the laboratory and perform...

418

ENGINEERING BULLETIN: IN SITU SOIL FLUSHING  

EPA Science Inventory

In situ soil flushing is the extraction of contaminants from the soil with water or other suitable aqueous solutions. Soil flushing is accomplished by passing the extraction fluid through in-place soils using an injection or infiltration process. Extraction fluids must be recover...

419

In situ vitrification on buried waste  

Microsoft Academic Search

In situ vitrification (ISV) is being evaluated as a remedial treatment technology for buried mixed and transuranic (TRU) wastes at the Subsurface Disposal Area (SDA) at Idaho National Engineering Laboratory (INEL) and can be related to buried wastes at other Department of Energy (DOE) sites. There are numerous locations around the DOE Complex where wastes were buried in the ground

1992-01-01

420

ENGINEERING BULLETIN: IN SITU BIODEGRADATION TREATMENT  

EPA Science Inventory

In situ biodegradation may be used to treat low-to-intermediate concentrations of organic contaminants in place without disturbing or displacing the contaminated media. lthough this technology hag been used to degrade a limited number of inorganics, specifically cyanide and nitra...

421

ENGINEERING BULLETIN: IN SITU BIODEGRADATION TREATMENT  

EPA Science Inventory

In situ biodegradation may be used to treat low-to-intermediate concentrations of organic contaminants in place without disturbing or displacing the contaminated media. Although this technology has been used to degrade a limited number of inorganics, specifically cyanide and nitr...

422

GAS TURBINE REHEAT USING IN SITU COMBUSTION  

Microsoft Academic Search

In situ reheat is an alternative to traditional gas turbine reheat design in which fuel is fed through airfoils rather than in a bulky discrete combustor separating HP and LP turbines. The goals are to achieve increased power output and\\/or efficiency without higher emissions. In this program the scientific basis for achieving burnout with low emissions has been explored. In

D. M. Bachovchin; R. A. Newby P. G. A. Cizmas

2004-01-01

423

ENGINEERING BULLETIN: IN SITU VITRIFICATION TREATMENT  

EPA Science Inventory

In situ vitrification (ISV) uses electrical power to heat and melt soil, sludge, mine tailings, buried wastes, and sediments contaminated with organic, inorganic, and metal-bearing hazardous wastes. The molten material cools to form a hard, monolithic, chemically inert, stable...

424

DEMONSTRATION BULLETIN: IN SITU VITRIFICATION - GEOSAFE CORPORATION  

EPA Science Inventory

in Situ Vitrification (ISV) is designed to treat soils, sludges, sediments, and mine tailings contaminated with organic and inorganic compounds. The process uses electrical current to heat (mett) and vitrify the soil in place. Organic contaminants are decomposed by the extreme h...

425

In-situ Vane Shear Test  

NSDL National Science Digital Library

This article briefly describes the in-situ shear vane test, including images and typical results. This procedure tests the undrained shear strength of soil. Procedures of the test are not outlined, but a general overview is given. The site contains photos, charts, diagrams and instructional test to help guide the user.

2008-09-24

426

Accelerated in situ bioremediation of groundwater  

SciTech Connect

In situ bioremediation, as applied in this project, is based on the principal of biostimulation: supplying nutrients to indigenous microbes to stimulate their metabolic activity and subsequent degradation of contaminants. Typically, a network of injection and extraction wells are used to recirculate groundwater into which amendments are added and distributed within the aquifer. The objective of the in situ process is to create in the aquifer a microbially active zone that maximizes contaminant destruction while controlling the distribution of microbial growth. It is important to control microbial growth to avoid plugging the aquifer near the injection well and to establish and sustain maximum treatment zones for each injection well. Figure I illustrates this concept for in situ bioremediation. The technology described herein is innovative in its use of the computer-based Accelerated Bioremediation Design Tool (ABDT) to aid in selecting appropriate system designs and to determine optimal operating strategies. In addition, numerical simulations within the design tool proved to be valuable during remediation operations to determine appropriate changes in the` operating strategy as the bioremediation process progressed. This is particularly important because in situ bioremediation is not a steady- state process, and corrective actions to operating parameters are typically needed to maintain both rapid destruction rates and hydraulic containment.

Truex, M.J.; Hooker, B.S.; Anderson, D.B.

1996-07-01

427

In-Situ Burning of Spilled Oil.  

ERIC Educational Resources Information Center

|Reviews in-situ burning with particular emphasis on how it can be applied in water-related oil spill situations. Presents and discusses the use of nomograms and development of techniques cited for safe and effective ignition and controlled burning of spilled oil. Includes representative oil spill scenarios and possible responses. (15 references)…

Allen, Alan A.

1991-01-01

428

Human Papillomavirus and Extragenital in situ Carcinoma  

Microsoft Academic Search

Background: The relation between human papillomavirus (HPV) and extragenital Bowen’s disease (BD) is controversial. Methods: This study used in situ hybridisation to evaluate the rate of HPV in extragenital cutaneous BD and investigated possible relations with immune status and exposure of skin to light. Results: HPV DNA was detected in 58% of 69 samples from 50 patients. The percentage of

G. Quéreux; J. M. N’Guyen; B. Dreno

2004-01-01

429

Investigation of Notchless In situ ?-Raman Spectroscopy  

Microsoft Academic Search

Micro-Raman spectroscopy is a powerful method for analyzing the bond structure of matter. The Laser Materials Processing group uses a femtosecond pulsed laser to create waveguides in Chalcogenide and Oxide glasses. Raman spectroscopy is used to identify changes in the glasses before and after laser irradiation. More effective is in situ Raman spectroscopy, tracking the changes in the glass in

Jordan Cox

430

In Situ Cleanable Alternative HEPA Filter Media  

Microsoft Academic Search

The Westinghouse Savannah River Company, located at the Savannah River Site in Aiken, South Carolina, is currently testing two types of filter media for possible deployment as in situ regenerable\\/cleanable High Efficiency Particulate Air (HEPA) filters. The filters are being investigated to replace conventional, disposable, glass-fiber, HEPA filters that require frequent removal, replacement, and disposal. This is not only costly

D. J. Adamson; M. T. Terry

2002-01-01

431

Durability of In-Situ Pipe Repair.  

National Technical Information Service (NTIS)

The objective of this research project is to determine the long term durability of various pipe repair methods used the Florida Department of Transportation (FDOT). By reviewing previous in-situ repairs performed on all of the optional pipe types allowed ...

D. Alwood D. McBride F. T. Najaji L. Muszynski T. Mamaghani W. G. Harris

2011-01-01

432

In situ hybridisation: principles and applications  

Microsoft Academic Search

In situ hybridisation (ISH) is based on the complementary pairing of labelled DNA or RNA probes with normal or abnormal nucleic acid sequences in intact chromosomes, cells or tissue sections. Compared with other molecular biology techniques applicable to anatomical pathology, ISH enjoys better rapport with histopathologists because of its similarity to immunohistochemistry. It has the unique advantage over other molecular

Lai Meng LOO; Phaik Leng

433

Rotational malposition during laser in situ keratomileusis  

Microsoft Academic Search

PURPOSE: To investigate the degree of rotational malposition in eyes undergoing laser in situ keratomileusis.DESIGN: Prospective observational study.METHODS: We measured the rotational position of 240 eyes of 169 patients who underwent treatment for myopic or hyperopic astigmatism with the Alcon Summit Autonomous (Orlando, Florida) LADARVision excimer laser. Immediately preoperatively, each eye was marked while the patient was seated upright. Rotational

Anil U. Swami; Roger F. Steinert; Winifred E. Osborne; April A. White

2002-01-01

434

A passive, in situ micro strain gauge  

Microsoft Academic Search

A passive micro strain gauge based on the strain magnification technique has been designed, demonstrated, and characterized. This strain gauge can be fabricated in situ along with active micro sensors or actuators on the same chip for monitoring residual strain effects. Both tensile or compressive strain could be easily observed under optical microscopes and the resolution of strains as small

Liwei Lin; Roger T. Howe; Albert P. Pisano

1993-01-01

435

Characterization of gamma-irradiated polyethylene terephthalate by liquid-chromatography mass-spectrometry (LC MS) with atmospheric-pressure chemical ionization (APCI)  

NASA Astrophysics Data System (ADS)

Low-molecular-weight (low-MW) constituents of polyethylene terephthalate (PET), irradiated with 60Co gamma rays at 25 and 50 kGy, were analyzed by HPLC MS with atmospheric-pressure chemical ionization (APCI). Consistent with earlier results, the concentrations of the major compounds that are present in the non-irradiated PET do not change perceptibly. However, we find a small but significant increase in terephthalic acid ethylester, from less than 1 mg/kg in the non-irradiated control to ca. 2 mg/kg after 50 kGy, which has not been described before. The finding is important because it gives an impression of the sensitivity of the analytical method. Additionally, it shows that even very radiation-resistant polymers can form measurable amounts of low-MW radiolysis products. The potential and limitations of LC MS for the analysis of radiolysis products and unidentified migrants are briefly discussed in the context of the question: How can we validate our analytical methods for unknown analytes?

Buchalla, Rainer; Begley, Timothy H.

2006-01-01

436

In Situ Cleanable Alternative HEPA Filter Media  

SciTech Connect

The Westinghouse Savannah River Company, located at the Savannah River Site in Aiken, South Carolina, is currently testing two types of filter media for possible deployment as in situ regenerable/cleanable High Efficiency Particulate Air (HEPA) filters. The filters are being investigated to replace conventional, disposable, glass-fiber, HEPA filters that require frequent removal, replacement, and disposal. This is not only costly and subjects site personnel to radiation exposure, but adds to the ever-growing waste disposal problem. The types of filter media being tested, as part of a National Energy Technology Laboratory procurement, are sintered nickel metal and ceramic monolith membrane. These media were subjected to a hostile environment to simulate conditions that challenge the high-level waste tank ventilation systems. The environment promoted rapid filter plugging to maximize the number of filter loading/cleaning cycles that would occur in a specified period of time. The filters were challenged using nonradioactive simulated high-level waste materials and atmospheric dust; materials that cause filter pluggage in the field. The filters are cleaned in situ using an aqueous solution. The study found that both filter media were insensitive to high humidity or moisture conditions and were easily cleaned in situ. The filters regenerated to approximately clean filter status even after numerous plugging and in situ cleaning cycles. Air Techniques International is conducting particle retention testing on the filter media at the Oak Ridge Filter Test Facility. The filters are challenged using 0.3-mm di-octyl phthalate particles. Both the ceramic and sintered media have a particle retention efficiency > 99.97%. The sintered metal and ceramic filters not only can be cleaned in situ, but also hold great potential as a long life alternative to conventional HEPA filters. The Defense Nuclear Facility Safety Board Technical Report, ''HEPA Filters Used in the Department of Energy's Hazardous Facilities'', found that conventional glass fiber HEPA filters are structurally weak and easily damaged by water or fire. The structurally stronger sintered metal and ceramic filters would reduce the potential of a catastrophic HEPA filter failure due to filter media breakthrough in the process ventilation system. An in situ regenerable system may also find application in recovering nuclear materials, such as plutonium, collected on glove box exhaust HEPA filters. This innovative approach of the in situ regenerative filtration system may be a significant improvement upon the shortfalls of conventional disposable HEPA filters.

Adamson, D. J.; Terry, M. T.

2002-02-28

437

A preliminary report on the determination of natural radioactivity levels of the State of Qatar using high-resolution gamma-ray spectrometry  

NASA Astrophysics Data System (ADS)

This study is aimed at the determination of the activity concentrations of naturally occuring and technically enhanced levels of radiation in soil samples collected across the landscape of Qatar. Representative soil samples from various locations across the Qatarian peninsula have been collected and analyzed in order to establish activity concentrations associated with the 235,8U and 232Th natural decay chains and also the long-lived naturally occurring radionuclide 40K. The activity concentrations have been measured using a hyper-pure germanium detector. Details of the sample preparation and the gamma-ray spectroscopic analysis techniques are presented, together with the preliminary values of the activity concentrations associated with the naturally occuring radionuclide chains for six soil samples collected from the Qatarian peninsula. Sample 228, which has been collected from an inshore oil-field area, was observed to have the highest observed value of 226Ra concentration among the six samples. The weighted mean values of the activity concentrations of the radionuclides 238U, 232Th and 40K in one particular sample (sample 228) were, respectively, found to be 213.9±1.4, 4.55±0.11 and 111.4±3.6 Bq/kg, which compare with the worldwide weighted mean values in soil samples, 33, 45 and 420 Bq/kg, respectively. The deduced activity concentration of 238U in sample 228 in the current work was found to be significantly higher than the worldwide average value and was also significantly higher than the values determined for the five other initial samples discussed here. The mean values of the activity concentration of the 232Th series, 40K and 137Cs in Bq/kg from the six investigated soil samples were found to be 9.4±1.3, 204±22 and 5.8±5.6, respectively, with the quoted uncertainty referring to the standard deviation among these measurements.

Al-Sulaiti, H.; Regan, P. H.; Bradley, D. A.; Malain, D.; Santawamaitre, T.; Habib, A.; Matthews, M.; Bukhari, S.; Al-Dosari, M.

2010-07-01

438

An attempt to use aerial gamma-ray spectrometry results in petrochemical assessments of the volcanic and plutonic associations of Central Anatolia (Turkey)  

NASA Astrophysics Data System (ADS)

Volcanic and magmatic rocks of Central Anatolia are fairly rich in radioelement concentrations. The aerial gamma-ray spectrometric survey data, gathered for the purpose of radioactive mineral exploration were utilized as an additional tool for the petrochemical classification of the volcanic and magmatics rocks and their environments. The survey data on acidic intrusions (e.g. granite, monzonite and syenite) have revealed radioelement concentrations to occur in wide ranges to be 2-6 wt per cent for potassium (K), 3-15 ppm for uranium (U) and 10-52 ppm for thorium (Th). The chain-like high and moderately high potassium, uranium and thorium anomalies on acid intrusives of the entire area show a halo-shaped feature. Locations and lithological compositions of the volcanic rocks namely lavas, tuffs, ignimbrites and basalts, appear to be reasonably effective on their radioelement concentrations. The highest potassium, uranium and thorium concentrations of the volcanic rocks are around 4 wt per cent, 10 ppm and 35 ppm, respectively. Consequently, depending on the location and composition, volcanics show a very wide range of air absorbed dose rate. The lowest rates, which vary between 10 and 120 nGy/hr, were calculated in the ophiolitic group, thick cultivated soil covering areas, particularly at the centre of the aerial survey area, metamorphosed rocks in the north and young basalts mostly in the Kayseri district. Their average radioelement concentrations were found to be very low, that is, 1.2 wt per cent, 2.3 ppm and 10 ppm for K, U and Th, respectively. Because of the accumulation of soluble uranium isotopes, air absorbed rates stemming from radioactivity of these isotopes at the vicinity of the Kozakl? hot spring reach 440 nGy/hr and exceed 150 nGy/hr at the vicinity of the Nev?ehir geothermal field.

Aydin, ?brahim; Aydo?an, M. Selman; Oksum, Erdinç; Koçak, Ali

2006-11-01

439

In-Situ Characterization of Underwater Radioactive Sludge  

SciTech Connect

A fundamental requirement underpinning safe clean-up technologies for legacy spent nuclear fuel (SNF) ponds, pools and wet silos is the ability to characterize the radioactive waste form prior to retrieval. The corrosion products resulting from the long term underwater storage of spent nuclear fuel, reactor components and reprocessing debris present a major hazard to facility decontamination and decommissioning in terms of their radioactive content and physical / chemical reactivity. The ability to perform in-situ underwater non-destructive characterization of sludge and debris in a safe and cost-effective manner offers significant benefits over traditional destructive sampling methods. Several techniques are available for underwater measurements including (i) Gross gamma counting, (ii) Low-, Medium- and High- Resolution Gamma Spectroscopy, (iii) Passive neutron counting and (iv) Active Neutron Interrogation. The optimum technique depends on (i) the radioactive inventory (ii) mechanical access restrictions for deployment of the detection equipment, interrogation sources etc. (iii) the integrity of plant records and (iv) the extent to which Acceptable Knowledge which may be used for 'fingerprinting' the radioactive contents to a marker nuclide. Prior deployments of underwater SNF characterization equipment around the world have been reviewed with respect to recent developments in gamma and neutron detection technologies, digital electronics advancements, data transfer techniques, remote operation capabilities and improved field ruggedization. Modeling and experimental work has been performed to determine the capabilities, performance envelope and operational limitations of the future generation of non-destructive underwater sludge characterization techniques. Recommendations are given on the optimal design of systems and procedures to provide an acceptable level of confidence in the characterization of residual sludge content of legacy wet storage facilities such that retrieval and repackaging of SNF sludges may proceed safely and efficiently with support of the regulators and the public. (author)

Simpson, A.P.; Clapham, M.J.; Swinson, B. [Pajarito Scientific Corp., Santa Fe, NM (United States)

2008-07-01

440

Making a Hybrid Microfluidic Platform Compatible for In Situ Imaging by Vacuum-Based Techniques  

SciTech Connect

A self-contained microfluidic-based device was designed and fabricated for in situ imaging of aqueous surfaces using vacuum techniques. The device is a hybrid between a microfluidic PDMS block and external accessories, all portable on a small platform (10 cm-8 cm). The key feature is that a small aperture with a diameter of 2-3 micrometers is opened to the vacuum, which serves as a detection window for in situ imaging of aqueous surfaces. Vacuum compatibility and temperature drop due to water vaporization are the two most important challenges in this invention. Theoretical calculations and fabrication strategies are presented from multiple design aspects. In addition, results from the time-of-flight secondary ion mass spectrometry (ToF-SIMS) of aqueous surfaces are presented.

Yang, Li; Yu, Xiao-Ying; Zhu, Zihua; Thevuthasan, Suntharampillai; Cowin, James P.

2011-10-26

441

In Situ Tritium Probe for Ground Water Monitoring  

NASA Astrophysics Data System (ADS)

The U.S. Department of Energy (USDOE)/National Nuclear Security Administration (NNSA) has requested a probe system that can provide daily measurements of tritium in ground waters, fit into 5 cm diameter ground water monitor wells, and survive extended periods (months to years) at hydrostatic pressures of 12,000 kPa (1800 psi) and water temperatures to 60oC. The analytical Minimum Detectable Limit Allowable (MDA) requested for tritium in solution is <1,000 picoCuries per liter (pCi L-1) and preferably <300 pCi L-1 (11 Bq L-1). The In Situ Tritium probe system (ITP) must produce analytical results without drawing a ground water sample to the surface while operating unattended and automatically download data from remote well sites without external power or communication lines. An ITP has been developed that satisfies most of these requirements. A prototype system that demonstrated proof-of-principal was deployed successfully in shallow monitor wells. Ground water samples were processed and analyzed onboard the prototype ITP and data automatically transmitted to the wellhead. A third generation tritium detection and measurement cell that quantitatively measures dissolved tritium at activities <2,000 pCi L-1 has been tested under laboratory conditions. This, or a more sensitive, detection cell will be integrated into the ITP platform and deployed for extensive tests in deep monitor wells at the USDOE/NNSA Nevada Test Site within the next two years. Ultimate goals for the ITP system are low detection limits for dissolved tritium (<300 pCi L-1) plus additional analytical capabilities for nuclear and chemical parameters such as in situ gamma and neutron fluxes, pH, EH, EC, concentrations of specific aqueous components, etc.

Hull, C.

2001-12-01

442

Raman Spectrometry.  

ERIC Educational Resources Information Center

Reviews mainly quantitative analytical applications in the field of Raman spectrometry. Includes references to other reviews, new and analytically untested techniques, and novel sampling and instrument designs. Cites 184 references. (CS)

Gardiner, Derek J.

1980-01-01

443

Raman Spectrometry.  

ERIC Educational Resources Information Center

|Reviews mainly quantitative analytical applications in the field of Raman spectrometry. Includes references to other reviews, new and analytically untested techniques, and novel sampling and instrument designs. Cites 184 references. (CS)|

Gardiner, Derek J.

1980-01-01

444

In situ remediation of uranium contaminated groundwater  

SciTech Connect

In an effort to develop cost-efficient techniques for remediating uranium contaminated groundwater at DOE Uranium Mill Tailing Remedial Action (UMTRA) sites nationwide, Sandia National Laboratories (SNL) deployed a pilot scale research project at an UMTRA site in Durango, CO. Implementation included design, construction, and subsequent monitoring of an in situ passive reactive barrier to remove Uranium from the tailings pile effluent. A reactive subsurface barrier is produced by emplacing a reactant material (in this experiment various forms of metallic iron) in the flow path of the contaminated groundwater. Conceptually the iron media reduces and/or adsorbs uranium in situ to acceptable regulatory levels. In addition, other metals such as Se, Mo, and As have been removed by the reductive/adsorptive process. The primary objective of the experiment was to eliminate the need for surface treatment of tailing pile effluent. Experimental design, and laboratory and field results are discussed with regard to other potential contaminated groundwater treatment applications.

Dwyer, B.P.; Marozas, D.C.

1997-02-01

445

Quantum criticality from in situ density imaging  

SciTech Connect

We perform large-scale quantum Monte Carlo (QMC) simulations for strongly interacting bosons in a two-dimensional optical lattice trap and confirm an excellent agreement with the benchmarking in situ density measurements by the Chicago group [N. Gemelke et al., Nature (London) 460, 995 (2009)]. We further present a general finite-temperature phase diagram for both the uniform and the trapped systems, demonstrating how the universal scaling properties near the superfluid-to-Mott insulator transition can be observed from the in situ density profile. The characteristic temperature to find such quantum criticality is estimated to be of the order of the single-particle bandwidth, which should be achievable in the present experiments. Finally, we examine the validity regime of the local fluctuation-dissipation theorem, which can be a used as a thermometry in the strongly interacting regime.

Fang Shiang; Chung, Chia-Min [Physics Department, National Tsing-Hua University, Hsinchu 300, Taiwan (China); Ma, Ping Nang [Theoretische Physik, ETH Zurich, CH-8093 Zurich (Switzerland); Chen Pochung; Wang, Daw-Wei [Physics Department, National Tsing-Hua University, Hsinchu 300, Taiwan (China); Physics Division, National Center for Theoretical Sciences, Hsinchu 300, Taiwan (China)

2011-03-15

446

In situ calibration using satellite data results  

NASA Astrophysics Data System (ADS)

The main goal of this work is the analysis of new approaches in order to study the properties of astronomical sites. The objective is to calibrate the atmospheric extinction provided by in situ techniques through remote sensing data retrieved from satellite-platforms. We have selected data provided by different spectrographs on board NASA and ESA satelites with better spatial and temporal resolutions than TOMS and centered on channels of astronomical interest as a possible tool for site characterization. In addition, from these satelite measurements it is possible to derive data related to the cloud coverage and climatic trends, or about the atmospheric turbulence from troposphere winds. The main problem to use these values is their interpretation and their quantitative calibration. Data analysis need to be complemented with those provided by in situ instruments (telescopes, airborne particles counters, ground meteorological stations, etc.).

Varela, A. M.; Bertolin, C.; Muñoz-Tuñón, C.; Fuensalida, J. J.; Ortolani, S.

2007-10-01

447

In situ bioremediation of Hanford groundwater  

SciTech Connect

Liquid wastes containing radioactive, hazardous, and regulated chemicals have been generated throughout the 40+ years of operations at the US Department of Energy`s (DOE) Hanford Site. Some of these wastes were discharged to the soil column and many of the waste components, including nitrate, carbon tetrachloride (CCl{sub 4}), and several radionuclides, have been detected in the Hanford groundwater. Current DOE policy prohibits the disposal of contaminated liquids directly to the environment, and remediation of existing contaminated groundwaters may be required. In situ bioremediation is one technology currently being developed at Hanford to meet the need for cost effective technologies to clean groundwater contaminated with CCl{sub 4}, nitrate, and other organic and inorganic contaminants. This paper focuses on the latest results of an on going effort to develop effective in situ remediation strategies through the use of predictive simulations.

Skeen, R.S.; Roberson, K.R.; Workman, D.J. [Pacific Northwest Lab., Richland, WA (United States); Petersen, J.N.; Shouche, M. [Washington State Univ., Pullman, WA (United States). Dept. of Chemical Engineering

1992-04-01

448

In situ bioremediation of Hanford groundwater  

SciTech Connect

Liquid wastes containing radioactive, hazardous, and regulated chemicals have been generated throughout the 40+ years of operations at the US Department of Energy's (DOE) Hanford Site. Some of these wastes were discharged to the soil column and many of the waste components, including nitrate, carbon tetrachloride (CCl{sub 4}), and several radionuclides, have been detected in the Hanford groundwater. Current DOE policy prohibits the disposal of contaminated liquids directly to the environment, and remediation of existing contaminated groundwaters may be required. In situ bioremediation is one technology currently being developed at Hanford to meet the need for cost effective technologies to clean groundwater contaminated with CCl{sub 4}, nitrate, and other organic and inorganic contaminants. This paper focuses on the latest results of an on going effort to develop effective in situ remediation strategies through the use of predictive simulations.

Skeen, R.S.; Roberson, K.R.; Workman, D.J. (Pacific Northwest Lab., Richland, WA (United States)); Petersen, J.N.; Shouche, M. (Washington State Univ., Pullman, WA (United States). Dept. of Chemical Engineering)

1992-04-01

449

DEMONSTRATION BULLETIN: IN SITU ELECTROKINETIC EXTRACTION SYSTEM - SANDIA NATIONAL LABORATORIES  

EPA Science Inventory

Sandia National Laboratories (SNL) has developed an in situ soil remediation system that uses electrokinetic principles to remediate hexavalent chromium-contaminated unsaturated or partially saturated soils. The technology involves the in situ application of direct current to the...

450

IN-SITU BIOREMEDIATION OF CONTAMINATED GROUND WATER  

EPA Science Inventory

In-Situ bioremediation, where applicable, appears to be a potential cost-effective and environmentally acceptable remediation technology. uflita (1989) identified characteristics of the ideal candidate site for successful implementation of in-situ bioremediation. hese characteris...

451

STEREO In-situ Data Analysis  

NASA Astrophysics Data System (ADS)

STEREO's IMPACT (In-situ Measurements of Particles and CME Transients) investigation provides the first opportunity for long duration, detailed observations of 1 AU magnetic field structures, plasma and suprathermal electrons, and energetic particles at points bracketing Earth's heliospheric location. The PLASTIC instrument takes plasma ion composition measurements completing STEREO's comprehensive in-situ perspective. Stereoscopic/3D information from the STEREO SECCHI imagers and SWAVES radio experiment make it possible to use both multipoint and quadrature studies to connect interplanetary Coronal Mass Ejections (ICME) and solar wind structures to CMEs and coronal holes observed at the Sun. The uniqueness of the STEREO mission requires novel data analysis tools and techniques to take advantage of the mission's full scientific potential. An interactive browser with the ability to create publication-quality plots has been developed which integrates STEREO's in-situ data with data from a variety of other missions including WIND and ACE. Static summary plots and a key-parameter type data set with a related online browser provide alternative data access. Finally, an application program interface (API) is provided allowing users to create custom software that ties directly into STEREO's data set. The API allows for more advanced forms of data mining than currently available through most web-based data services. A variety of data access techniques and the development of cross- spacecraft data analysis tools allow the larger scientific community to combine STEREO's unique in-situ data with those of other missions, particularly the L1 missions, and, therefore, to maximize STEREO's scientific potential in gaining a greater understanding of the heliosphere.

Schroeder, P. C.; Luhmann, J. G.; Davis, A. J.; Russell, C. T.

2007-05-01

452

Numerical simulation of in situ bioremediation  

SciTech Connect

Models that couple subsurface flow and transport with microbial processes are an important tool for assessing the effectiveness of bioremediation in field applications. A numerical algorithm is described that differs from previous in situ bioremediation models in that it includes: both vadose and groundwater zones, unsteady air and water flow, limited nutrients and airborne nutrients, toxicity, cometabolic kinetics, kinetic sorption, subgridscale averaging, pore clogging and protozoan grazing.

Travis, B.J.

1998-12-31

453

Hydrogen Generation During In-Situ Combustion  

Microsoft Academic Search

BP Resources Canada Ltd. is operating an oxygen in-situ oil recovery pilot at Marguerite Lake, part of the Cold Lake heavy-oil deposit in eastern Alberta. The pilot consists of two principal areas: a three-well, wet air combustion test and an infill-drilled, four five-spot, wet oxygen combustion project on 2 hectare spacing (5 acres). All the wells were initially steam fractured

L. E. Hajdo; R. J. Hallam; L. D. L. Vorndran

1985-01-01

454

Non-radioactive in situ hybridization  

Microsoft Academic Search

A number of immunocytochemical detection systems for determining the chromosomal localization of specific nucleic acid sequences by non-radioactive in situ hybridization have been compared. The procedures were: 1. the peroxidase\\/diaminobenzidine (PO\\/DAB) combination, either or not gold\\/silver intensificated; 2. alkaline phosphatase marking using the nitro-blue tetrazolium plus bromochloro-indolyl phosphate substrate combination (AP\\/NBT+CIP); and 3. immunogold with or without silver enhancement. The

A. F. M. Cremers; N. Jansen in de Wal; J. Wiegant; R. W. Dirks; P. Weisbeek; M. Ploeg; J. E. Landegent

1987-01-01

455

In-situ alcoholysis of soybean oil  

Microsoft Academic Search

In-situ alcoholysis of soybean oil with methanol, ethanol,n-propanol, andn-butanol was investigated, as well as the extraction of the oil with these solvents, to explain the progress ofin-situ alcoholysis and to determine the parameters that affect this reaction. Because methanol is a poor solvent for soybean oil,\\u000a the amount of oil dissolved in methanol and converted to methyl esters was low

Gökhan Kildiran; Sevil Özgül Yücel; Selma Türkay

1996-01-01

456

A new method of in situ hybridization  

Microsoft Academic Search

A new method for gene mapping at the chromosome level using in situ hybridization and scanning electron microscopy is described and has been applied to mapping the rRNA genes of Drosophila melanogaster. Biotin is covalently attached to Drosophila rRNA via a cytochrome c bridge at a ratio of one cytochrome-biotin per 130 nucleotides by a chemical procedure. Polymethacrylate spheres with

Jerry E. Manning; N. Davis Hershey; Thomas R. Broker; Maria Pellegrini; Herschel K. Mitchell; Norman Davidson

1975-01-01

457

Excursion control at in situ uranium mines  

SciTech Connect

This paper summarizes excursions (uncontrolled movement of lixiviant beyond the ore zone) based on case histories of 8 in situ uranium mines (7 in Wyoming and 1 in Texas). These case histories were compiled from data provided by the US Nuclear Regulatory Commission, the Wyoming Department of Environmental Quality, and the Texas Department of Water Resources. Most of these data were provided to the above agencies by mining companies in response to regulatory requirements pertaining to licensing actions.

Staub, W.P.

1987-01-01

458

Endothelial decompensation after laser in situ keratomileusis  

Microsoft Academic Search

We report the results of laser in situ keratomileusis (LASIK) in a 58-year-old woman with a history of corneal guttata in the right eye and mild Fuchs’ dystrophy in the left eye. Preoperative pachymetry was 586 ?m and 656 ?m, respectively. The surgical treatment was +1.50 diopters (D) in the right eye and +3.25 D in the left eye. Surgery

David T Vroman; Kerry D Solomon; Mike P Holzer; Qun Peng; David J Apple; Esther M Bowie

2002-01-01

459

In Situ Synthesis of Rubber Nanocomposites  

Microsoft Academic Search

\\u000a The preparation and characterization of rubber based nanocomposites prepared by in situ generation of inorganic oxides by means of the hydrolytic sol–gel process are reviewed in the present chapter. The sol–gel approach has been applied to several rubber matrices to prepare reinforced\\u000a vulcanized and unvulcanized rubbers. Several synthetic procedures are presented while the most investigated filler is silica\\u000a obtained by

Massimo Messori

460

In-Situ Geochronology using Resonance Ionization  

Microsoft Academic Search

We are developing a miniature laser ablation resonance ionization mass spectrometer for in-situ isotopic measurements on Mars and other solid bodies, with a focus on Rb-Sr geochronology. Using a lab instrument built from off-the-shelf components, we have achieved a precision that is within a factor of four of that required to support Rb-Sr geochronology (87Sr\\/86Sr to ±0.0002 required, ±0.0008 demonstrated).

F. S. Anderson; T. Whitaker; K. Nowicki; S. Sherman; J. Mahoney; D. Young; G. Miller; B. Peterson

2007-01-01