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1

Radioactivity measurements in the aquatic environment using in-situ and laboratory gamma-ray spectrometry.  

PubMed

The in-situ underwater gamma-ray spectrometry method is validated by inter-comparison with laboratory method. Deployments of the spectrometer KATERINA on a submarine spring and laboratory measurements of water samples with HPGe detector were performed. Efficiency calibrations, Monte Carlo simulations and the Minimum Detectable Activity (MDA) estimations were realized. MDAs varied from 0.19 to 10.4 (lab) and 0.05 to 0.35 (in-situ) Bq/L, while activity concentrations differed from 7% (for radon progenies) up to 10% (for (40)K), between the two methods. PMID:24103707

Eleftheriou, G; Tsabaris, C; Androulakaki, E G; Patiris, D L; Kokkoris, M; Kalfas, C A; Vlastou, R

2013-12-01

2

Monte Carlo simulation by GEANT 4 and GESPECOR of in situ gamma-ray spectrometry measurements.  

PubMed

The application of GEANT 4 and GESPECOR Monte Carlo simulation codes for efficiency calibration of in situ gamma-ray spectrometry was studied. The long computing time required by GEANT 4 prevents its use in routine simulations. Due to the application of variance reduction techniques, GESPECOR is much faster. In this code specific procedures for incorporating the depth profile of the activity were implemented. In addition procedures for evaluating the effect of non-homogeneity of the source were developed. The code was validated by comparison with test simulations carried out with GEANT 4 and by comparison with published results. PMID:23566809

Chirosca, Alecsandru; Suvaila, Rares; Sima, Octavian

2013-11-01

3

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

PubMed

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 microSv y(-1)). PMID:9314225

Uyttenhove, J; Pommé, S; Van Waeyenberge, B; Hardeman, F; Buysse, J; Culot, J P

1997-10-01

4

Spatially-Dependent Measurements of Surface and Near-Surface Radioactive Material Using In situ Gamma Ray Spectrometry (ISGRS) For Final Status Surveys  

SciTech Connect

In-situ, high-resolution gamma-ray spectrometry (ISGRS) measurements were conducted at the Oak Ridge Institute for Science and Education (ORISE) field laboratory in Oak Ridge, Tennessee. The purpose of these tests was to provide analytical data for assessing how “fit for use” this technology is for detecting discrete particles in soil.

J. A. Chapman, A. J. Boerner, E. W. Abelquist

2006-11-15

5

Assay for uranium and determination of disequilibrium by means of in situ high resolution gamma-ray spectrometry  

USGS Publications Warehouse

Two sealed sondes, using germanium gamma-ray detectors cooled by melting propane, have been field tested to depths of 79 m in water-filled boreholes at the Pawnee Uranium Mine in Bee Co., Texas. When, used as total-count devices, the sondes are comparable in logging speed and counting rate with conventional scintillation detectors for locating zones of high radioactivity. When used with a multichannel analyzer, the sondes are detectors with such high resolution that individual lines from the complex spectra of the uranium and thorium series can be distinguished. Gamma rays from each group of the uranium series can be measured in ore zones permitting determination of the state of equilibrium at each measurement point. Series of 10-minute spectra taken at 0.3- to 0.5-m intervals in several holes showed zones where maxima from the uranium group and from the 222Rn group were displaced relative to each other. Apparent excesses of 230Th at some locations suggest that uranium-group concentrations at those locations were severalfold greater some tens of kiloyears, ago. At the current state of development a 10-minute count yields a sensitivity of about 80 ppm U308. Data reduction could in practice be accomplished in about 5 minutes. The result is practically unaffected by disequilibrium or radon contamination. In comparison with core assay, high-resolution spectrometry samples a larger volume; avoids problems due to incomplete core recovery, loss of friable material to drilling fluids, and errors in depth and marking; and permits use of less expensive drilling methods. Because gamma rays from the radionuclides are accumulated simultaneously, it also avoids the problems inherent in trying to correlate logs made in separate runs with different equipment. Continuous-motion delayed-gamma activation by a 163-?g 252Cf neutron source attached to the sonde yielded poor sensitivity. A better neutron-activation method, in which the sonde is moved in steps so as to place the detector at the previous activation point, could not be evaluated because of equipment failure.

Tanner, Allan B.; Moxham, Robert M.; Senftle, F. E.

1977-01-01

6

In situ gamma spectroscopy in environmental research and monitoring.  

PubMed

In situ gamma spectroscopy was introduced to determine the outdoor gamma dose rate from soil and to calculate the radionuclide concentration and the relative contribution to the dose rate. This paper reviews the most common and proven applications of in situ gamma spectroscopy-together with the most recent and innovative research outcomes obtained with this technique, particularly for its use indoors. Advantages and limitations of its utilization to assess environmental radioactivity-indoors and outdoors-are also discussed. PMID:18511287

Nuccetelli, Cristina

2008-11-01

7

Factors influencing in situ gamma-ray measurements  

Microsoft Academic Search

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

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

2009-01-01

8

Spatial mapping of soil and radioactivity redistribution at the hillslope scale using in-situ gamma spectrometry, terrestrial laser scanning and RFID tags after the Fukushima nuclear accident fallout.  

NASA Astrophysics Data System (ADS)

In March 2011, the Fukushima Daiichi Nuclear Power Plant disaster, triggered by the Tohoku earthquake and the consequent tsunami, released a large amount of radionuclides in the environment. To provide a rapid assessment of the soil contamination and its potential redistribution, intensive scientific monitoring has been conducted since July 2011 in our study site, located in the Yamakiya district of Kawamata town, in Fukushima prefecture, Japan, about 37 km from the power plant. In this paper, we summarize and analyze a dataset combining multiple innovative methods deployed inside a 5m x 22m bounded hillslope plot. In addition to runoff volumes and sediments radiocesium concentrations, each major rainfall event was followed by in situ gamma spectrometry measurements. In 2012, to trace the complex behavior of sediments inside the plot, about 300 RFID (Radio-Frequency IDentification) tags representing coarse sediments were scattered and their spatial position was periodically checked using a total station. Finally, several high resolutions Digital Elevation Models were acquired with a terrestrial laser scanner to assess the surface structure and changes. The observed processes at the event scale include interrill and rill erosion, as well as local deposition and remobilization phenomenon. Not only do they directly provide information on the erosion spatio-temporal variability and the associated radionuclides transfers, but combined together they can constitute a solid basis to improve and challenge process-based distributed erosion models.

Patin, Jeremy; Onda, Yuichi; Noguchi, Takehiro; Parsons, Anthony

2013-04-01

9

Uncertainty analysis of in-situ gamma spectrometry measurements of air cleaning filter cartridges and 200 L drums by a HPGe detector.  

PubMed

This work deals with most significant sources of uncertainty in determination of radionuclides massic activity in 200 L drums with radioactive waste (RAW) from decommissioning of nuclear power plant (NPP) A1 and operational air cleaning filters coming from different parts of NPP's ventilation system. It turned out that the most significant source of uncertainty is determination of photo peak detection efficiency, in particular measurement geometry. The detection efficiency of HPGe detector has been determined by calculation using ISOCS software (In Situ Object Counting System) and detector characteristics delivered by the manufacturer (LABSOCS). The detector efficiency is influenced by various factors like measurement geometry, deviation from standard geometry, environmental characteristics, sample properties (density, material composition), used collimator etc. Mentioned factors and their contributions to the uncertainty of detection efficiency and thus to the total uncertainty of massic activity determination have been individually evaluated in the paper. The main part of the work consists of evaluation of maximum uncertainty factor due to presence of hypothetical point source in measurement volume for both types of measurement geometry. PMID:19945884

Slaninka, Alojz; Slávik, Ondrej; Necas, Vladimír

2010-01-01

10

In Situ Underwater Gamma Spectroscopy System. Innovative Technology Summary Report  

SciTech Connect

The baseline approach to characterize underwater objects is to use radiation sensors on an extendable pole or the Remote Underwater Characterization System to detect gamma radiation and to collect samples for laboratory analysis to determine concentrations of specific radionuclides. The In-Situ Underwater Gamma Spectroscopy (ISUGS) System is essentially a submersible In-Situ Object Counting System from Canberra that can determine both the total gamma radiation and quantify the specific radionuclides contributing to the radiation. ISUGS was demonstrated to characterize objects in the canal of the Materials Test Reactor in INEEL's Test Reactor Area. Cost analysis based on demonstration data revealed that ISUGS reduced costs by 80% for characterization of ten objects compared to the baseline approach. Frammatome provides ISUGS as part of its characterization services. Based on these promising results, INEEL and other DOE sites plan to use ISUGS to characterize their reactor fuel pools.

None

2001-06-01

11

Monitoring Genetic & Metabolic Potential for In Situ Bioremediation: Mass Spectrometry  

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, we are developing methods based on matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) for rapid and accurate detection of polymerase chain reaction (PCR) products from microbial genes involved in biodegradation of pollutants. PCR primers are being developed to amplify DNA sequences that are amenable to MALDI-MS detection. This work will lay the foundation for development of a field-portable MS-based technique for rapid on site assessment and monitoring of bioremediation processes.

Buchanan, Michelle V.; Hurst, Gregory B.; Lidstrom, Mary E.; Auman, Anne; Britt, Phillip F.; Costello, Andria; Doktycz, Mitchel; Kim, Yongseong

1999-06-01

12

In situ mass spectrometry of autoimmune liver diseases  

PubMed Central

Primary biliary cirrhosis (PBC), primary sclerosing cholangitis (PSC) and autoimmune hepatitis (AIH) are the major forms of autoimmune liver diseases each characterized by the destruction of a specific liver cell type and the presence of differing auto-antibodies. We took a proteomic approach utilizing in situ matrix-assisted laser desorption/ionization mass spectrometry (MALDI MS) to obtain profiles directly from liver samples of patients with PBC, PSC, AIH and controls. The ability to precisely localize the region for acquisition of MALDI MS allowed us to obtain profiles from bile ducts, inflammatory infiltrates and hepatocytes from each biopsy sample. Analysis tools developed to identify peaks and compare peaks across diseases and cell types were used to develop models to classify the samples. Using an initial set of testing samples from PBC patients and controls, we identified unique peaks present in bile ducts, inflammatory infiltrates and hepatocytes that could classify samples in a validation cohort with 88–91% accuracy. Interestingly, profiles of PSC and AIH did not differ significantly from PBC. Identification of proteins in these peaks may represent novel autoantigens or effector molecules. These findings illustrate the potential of a proteomic approach to autoimmune diseases with in situ MALDI MS.

Bowlus, Christopher L; Seeley, Erin H; Roder, Joanna; Grigorieva, Julia; Roder, Heinrich; Caprioli, Richard M; Gershwin, M Eric

2012-01-01

13

Time series data from routine in situ gamma spectroscopy measurements.  

PubMed

Time series of in situ gamma spectroscopy data from 6 sites, obtained over a period of 13 years as part of a routine surveillance program, have been investigated for variability, reproducibility and occurrence of trends. Natural isotopes ((40)K, (208)Tl, (212)Pb and (214)Pb) show variability up to a factor of 2, with time patterns varying from site to site. At five (level) sites (137)Cs values decreased at a rate higher than given by the physical half-life, consistent with literature data on migration of Cs. At one (downhill) site, an increase of (137)Cs with time was observed. The finding can be explained by erosion processes from uphill territories. The observed variations were larger than the experimental uncertainty, and the equipment long-term stability appeared to be satisfactory. It can be concluded that the obtained routine in situ data provide a valuable data pool with potential usefulness for scientific work. PMID:23395136

Fischer, Helmut W; Hettwig, Bernd

2013-11-01

14

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

15

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

16

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...

17

Technology information profile: RL321103 -- In situ gamma spectrometer  

SciTech Connect

Past operations of uranium production and support facilities at several Department of Energy (DOE) sites have occasionally resulted in the local contamination of some surface and subsurface soils. Such contamination commonly occurs within waste burial sites, cribs, pond bottom sediments, and areas surrounding waste tanks or uranium scrap, ore, tailing, and slag heaps. The thorough cleanup of these sites is a major public concern and a high priority for the DOE, but before any effective remedial protocols can be established, the three-dimensional distributions of the uranium contaminants must be adequately characterized. Unfortunately, traditional means of obtaining soil activities (e.g., grab sampling followed by laboratory analyses) are notoriously cumbersome, expensive, time-consuming, and often non-representative when very large areas are being surveyed. Hence, new technologies must be developed, or existing ones improved, to allow for the cheaper, better, faster (i.e., real-time) and safer characterization of uranium concentrations at these critical sites. The primary objective for this program is to develop, construct, and field/pilot test the in situ gamma spectrometer for the rapid measurement of uranium in surface and shallow subsurface soils at the Fernald site in Ohio.

Schilk, A.J.

1993-11-01

18

Neutral beam species measurements using in situ Rutherford backscatter spectrometry  

Microsoft Academic Search

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 ms, 1.6 MW, were Rutherford backscattered at 135° from the TiC inner neutral beam armor of the PDX, and detected

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

1985-01-01

19

Neutral beam species measurements using in situ Rutherford backscatter spectrometry  

Microsoft Academic Search

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° from TiC inner neutral beam armor of the PDX, and detected

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

1984-01-01

20

Janus probe, a detection system for high energy reactor gamma-ray spectrometry  

SciTech Connect

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 gamma-ray spectrometry. To meet these specific needs, a method of continuous gamma-ray spectrometry, namely Compton Recoil Gamma-Ray Spectrometry, was developed for in-situ observations of reactor environments. A new gamma-ray detection system has been developed which extends the applicability of Compton Recoil Gamma-Ray Spectrometry up to roughly 7 MeV. This detection system is comprised of two separate Si(Li) detectors placed face-to-face. Hence this new detection system is called the Janus probe. Also shown is the block diagram of pulse processing instrumentation for the Janus probe. This new gamma probe not only extends the upper energy limit of in-core gamma-ray spectrometry, but in addition possesses other fundamental advantages.

Gold, R.; Kaiser, B.J.

1980-03-01

21

In situ metabolomic mass spectrometry imaging: recent advances and difficulties.  

PubMed

MS imaging (MSI) is a remarkable new technology that enables us to determine the distribution of biological molecules present in tissue sections by direct ionization and detection. This technique is now widely used for in situ imaging of endogenous or exogenous molecules such as proteins, lipids, drugs and their metabolites, and it is a potential tool for pathological analysis and the investigation of disease mechanisms. MSI is also thought to be a technique that could be used for biomarker discovery with spatial information. The application of MSI to the study of endogenous metabolites has received considerable attention because metabolites are the result of the interactions of a system's genome with its environment and a total set of these metabolites more closely represents the phenotype of an organism under a given set of conditions. Recent studies have suggested the importance of in situ metabolite imaging in biological discovery and biomedical applications, but several issues regarding the technical application limits of MSI still remained to be resolved. In this review, we describe the capabilities of the latest MSI techniques for the imaging of endogenous metabolites in biological samples, and also discuss the technical problems and new challenges that need to be addressed for effective and widespread application of MSI in both preclinical and clinical settings. PMID:22366554

Miura, Daisuke; Fujimura, Yoshinori; Wariishi, Hiroyuki

2012-08-30

22

An in situ silver cationization method for hydrocarbon mass spectrometry.  

PubMed

We have developed a novel cationization method for the analysis of long-chain hydrocarbons via UV laser desorption mass spectrometry. In this technique we electrospray a thin coating of AgNO3 over a sample and perform UV laser desorption to produce Ag+ cationization of sample molecules. Use of this technique in our microscope/TOF-MS allows us to determine the spatial distribution of the species we detect in the sample. We demonstrate 8-mu spatial resolution, and submicron resolution is possible in principle. In mixed samples containing aromatic and aliphatic compounds, the aromatic compounds ionize directly and do not form adducts, and thus give single peaks as opposed to doublets from silver cations. This enables distinction between aromatic and aliphatic compounds that are in the same sample. PMID:15792711

Grace, Louis I; Abo-Riziq, Ali; deVries, Mattanjah S

2005-04-01

23

In situ measurements of thermospheric composition, temperature, and winds by mass spectrometry  

NASA Technical Reports Server (NTRS)

Mass spectrometry, in which a beam of electrons ionizes a sample of atmospheric gas and then analyses the ions thus produced to determine the concentration of each species in the sample, is presently evaluated as a basis for the study of earth atmosphere and other planetary atmospheres' properties. Recent applications of in situ mass spectrometry have measured thermospheric neutral gas composition, temperatures, and winds, with a spatial resolution sufficiently high to reveal previously unsuspected atmospheric variability. It is expected that analyses of these data will lead to a more detailed understanding of the deposition processes governing the thermosphere's highly variable structure.

Spencer, N. W.; Carignan, G. R.

1988-01-01

24

[In situ and rapid identification of tea by direct analysis in real time mass spectrometry].  

PubMed

By applying an ambient mass spectrometric method--direct analysis in real time mass spectrometry (DART MS), a method was developed for rapid identification of the principal constituents in different kinds of tea. The identification of different kinds of tea was also achieved by characteristic mass spectrometric signals. Under atmospheric pressure, DART MS method does not require any sample preparation, greatly reduces the analysis time, realizes the in situ, rapid, accurate, and high-throughput analysis. PMID:22097797

Zhang, Jialing; Zhang, Wei; Zhou, Zhigui; Bai, Yu; Liu, Huwei

2011-07-01

25

Detection of nitrifying bacteria in activated sludge by fluorescent in situ hybridization and fluorescence spectrometry  

Microsoft Academic Search

16S rRNA-targeted oligonucleotide probes for eubacteria (EUB338), ammonium-oxidizing bacteria (Nsm156) and nitrite-oxidizing bacteria (Nb1000) were used for the rapid detection of nitrifying bacteria in the activated sludge of a pilot nitrifying reactor by whole-cell, fluorescent in situ hybridization (FISH). Emission scanning and synchronous scanning fluorescence spectrometry were used to measure the hybridization. The binding of the probes at a temperature

In S. Kim; Volodymyr N. Ivanov

2000-01-01

26

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

27

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

PubMed

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(-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: 40K, 214Pb, 214Bi, 208Tl, and 228Ac. 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, 214Pb, 214Bi, and 228Ac showed a weak site dependence while the other two nuclides, 40K and 208Tl, 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. PMID:9228170

Benke, R R; Kearfott, K J

1997-08-01

28

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

NASA Technical Reports Server (NTRS)

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 our technology development program at NASA Goddard Space Flight Center's (NASA/GSFC) Astrochemistry Laboratory is to extend the application of neutron interrogation techniques to landed in situ planetary composition measurements by using a 14 MeV Pulsed Neutron Generator (PNG) combined with neutron and gamma ray detectors, to probe the surface and subsurface of planetary bodies without the need to drill. We are thus working to bring the PING instrument to the point where it can be flown on a variety of surface lander or rover missions to the Moon, Mars, Venus, asteroids, comets and the satellites of the outer planets.

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

2011-01-01

29

Parametric Studies for 233U Gamma Spectrometry  

SciTech Connect

Quantification of special nuclear material is a necessary aspect to assuring material accountability and is often accomplished using non-destructive gamma spectrometry. For 233U, gamma rays are affected by matrix and packaging attenuation and by a strong Compton continuum from decay products of 232U (inherently found in 233U) that obscure 233U gamma photopeaks. This project, based on current work at the national repository for separated 233U located at Oak Ridge National Laboratory (ORNL), explores the effects of various parameters on the quantification of 233U– including material form and geometry. Using an attenuation correction methodology for calculating the mass of 233U from NDA analysis, a bias of almost 75% less than the actual 233U mass was identified. The source of the bias needs to be understood at a more fundamental level for further use of this quantification method. Therefore, controlled experiments using well characterized packages of 233U were conducted at the repository and are presented in this paper.

Scheffing, C.C.; Krichinsky, A.

2004-01-01

30

In situ gamma spectroscopy to characterize building materials as radon and thoron sources.  

PubMed

In situ gamma spectroscopy is widely utilized to determine the outdoor gamma dose rate from the soil and to calculate the natural and artificial radionuclide concentration and their contribution to the dose rate. The application of in situ gamma spectroscopy in indoor environments can not supply quantitative information about activity concentration of radionuclides in building materials, but this technique can provide interesting information about building materials as radon source. In fact, a method based on analyses of gamma spectra data has been developed by the authors to provide, in field, quantitative estimation of disequilibrium in 226Ra and 228Ac sub-chains due to 222Rn and 220Rn exhalation. The method has been applied to data of gamma spectroscopy measurements carried out with HPGe detector (26%) in seven dwellings and one office in Rome. The first results of the data analysis show that, as regards especially the 226Ra sub-chain disequilibrium, different building materials (tuff, concrete, etc.) can show very different characteristics. If, in addition to the spectrometric data, other indoor environment parameters (indoor gamma dose rates, room dimensions, wall thickness, etc.) (Bochicchio et al., Radiat Prot Dosim 1994;56(1-4):137-140; Bochicchio et al., Environ Int 1996a;22:S633-S639) are utilized in a room model, an evaluation of 226Ra, 228Ac and 40K activity concentration and an indication of the exhalation features, by means of estimation of exhaled 222Rn activity concentration, can be achieved. PMID:11379933

Nuccetelli, C; Bolzan, C

2001-05-14

31

Angular response of a HPGe detector to gamma-rays in in situ measurements  

Microsoft Academic Search

The angular response of a HPGe detector used in in situ measurements was determined empirically as a function of gamma-ray energy at two source–detector geometries — the standard 1m and the non-standard 0.1m heights above ground. Values calculated by a Monte Carlo code were found to agree well with the experimental values. The code is thus labor-saving, because it can

Y. Nir-El; O. Sima

2001-01-01

32

Use of Gamma Spectrometry Method for Environmental Monitoring in the area of NPP  

NASA Astrophysics Data System (ADS)

It is generally not possible to correctly determine the long and short term impact of human activity upon the environment, without thorough processing of data, obtained through monitoring. It was confirmed that such impact on the environment must be monitored over a long time period. The data obtained must be of high quality, an attribute assured by present state of scientific knowledge. One of the well established methods for monitoring atmospheric deposition of radionuclides in the environment is laboratory and in situ gamma spectrometry. With the aim to monitor an occurrence of a one-time escape or persistent release of fission products into the air, resulting from an operation of a nuclear plant, two types of monitoring are performed: i/ measurement of samples from the environment (Schreber moss, forest humus, pine bark, mushrooms and forest berries) using laboratory gamma spectrometry method in the range up to 3 MeV (those data are used for the trend analysis and for the construction of the contaminationmaps); ii/ in situ gama spectrometry for assessment dosimetry and spectrometry characteristic of photon-fields (those data are used for the dose rate calculation).

Thinova, L.; Cechak, T.; Kluson, J.; Trojek, T.

2006-05-01

33

Matrix-Assisted Laser Desorption Ionization Imaging Mass Spectrometry: In Situ Molecular Mapping  

PubMed Central

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.

Angel, Peggi M.; Caprioli, Richard M.

2013-01-01

34

Laser-induced shock wave plasma spectrometry using a small chamber designed for in situ analysis  

NASA Astrophysics Data System (ADS)

Direct spectrochemical analyses on large bulk samples such as metal plates have been performed by using a small vacuum chamber, which was attached directly to the sample surface through an o-ring. This technique allowed the in situ generation of laser plasma and hence overcome to a good extent the inconvenient and sometime clumsy sample preparation procedure required in Laser-Induced Shock Wave Plasma Spectrometry. Additionally, the presence of the o-ring near the target surface effectively shielded off the surrounding area from the undesirable continuum emission from the primary plasma, and thereby enhanced the detection sensitivity of this technique. Using zinc plate and Pb glass as samples, it was further demonstrated in this experiment that even the time-integrated spectra, obtained by employing an OMA system, still exhibited a lower background than those obtained by ordinary time-resolved Laser-Induced Breakdown Spectroscopy.

Kurniawan, Hendrik; Jie Lie, Tjung; Kagawa, Kiichiro; On Tjia, May

2000-07-01

35

Laser Time-of-Flight Mass Spectrometry for Future In Situ Planetary Missions  

NASA Technical Reports Server (NTRS)

Laser desorption/ionization time-of-flight mass spectrometry (LD-TOF-MS) is a versatile, low-complexity instrument class that holds significant promise for future landed in situ planetary missions that emphasize compositional analysis of surface materials. Here we describe a 5kg-class instrument that is capable of detecting and analyzing a variety of analytes directly from rock or ice samples. Through laboratory studies of a suite of representative samples, we show that detection and analysis of key mineral composition, small organics, and particularly, higher molecular weight organics are well suited to this instrument design. A mass range exceeding 100,000 Da has recently been demonstrated. We describe recent efforts in instrument prototype development and future directions that will enhance our analytical capabilities targeting organic mixtures on primitive and icy bodies. We present results on a series of standards, simulated mixtures, and meteoritic samples.

Getty, S. A.; Brinckerhoff, W. B.; Cornish, T.; Ecelberger, S. A.; Li, X.; Floyd, M. A. Merrill; Chanover, N.; Uckert, K.; Voelz, D.; Xiao, X.; Tawalbeh, R.; Glenar, D.; Elsila, J. E.; Callahan, M.

2012-01-01

36

Extractive electrospray ionization mass spectrometry toward in situ analysis without sample pretreatment.  

PubMed

A homemade novel nanoextractive electrospray ionization (nanoEESI) source has been characterized for in situ mass spectrometric analysis of ambient samples without sample pretreatment. The primary ions generated using a nanospray emitter interact with the neutral sample plume created by manually nebulizing liquid samples, allowing production of the analyte ions in the spatial cross section of the nanoEESI source. The performance of nanoEESI is experimentally investigated by coupling the nanoEESI source to a commercial LTQ mass spectrometer for rapid analysis of various ambient samples using positive/negative ion detection modes. Compounds of interest in actual samples such as aerosol drug preparations, beverages, milk suspensions, farmland water, and groundwater were unambiguously detected using tandem nanoEESI ion trap mass spectrometry. The limit of detection was low picogram per milliliter levels for the compounds tested. Acceptable relative standard deviation (RSD) values (5-10%) were obtained for direct measurement of analytes in complex matrixes, providing linear dynamic signal responses using manual sample introduction. A single sample analysis was completed within 1.2 s. Requiring no sheath gas for either primary ion production or neutral sample introduction, the nanoEESI has advantages including readiness for miniaturization and integration, simple maintenance, easy operation, and low cost. The experimental data demonstrate that the nanoEESI is a promising tool for high-throughput, sensitive, quantitative, in situ analysis of ambient complex samples, showing potential applications for in situ analysis in multiple disciplines including but not limited to pharmaceutical analysis, food quality control, pesticides residue detection, and homeland security. PMID:19673501

Li, Ming; Hu, Bin; Li, Jianqiang; Chen, Rong; Zhang, Xie; Chen, Huanwen

2009-09-15

37

MALDI Mass Spectrometry Imaging for Visualizing In Situ Metabolism of Endogenous Metabolites and Dietary Phytochemicals  

PubMed Central

Understanding the spatial distribution of bioactive small molecules is indispensable for elucidating their biological or pharmaceutical roles. Mass spectrometry imaging (MSI) enables determination of the distribution of ionizable molecules present in tissue sections of whole-body or single heterogeneous organ samples by direct ionization and detection. This emerging technique is now widely used for in situ label-free molecular imaging of endogenous or exogenous small molecules. MSI allows the simultaneous visualization of many types of molecules including a parent molecule and its metabolites. Thus, MSI has received much attention as a potential tool for pathological analysis, understanding pharmaceutical mechanisms, and biomarker discovery. On the other hand, several issues regarding the technical limitations of MSI are as of yet still unresolved. In this review, we describe the capabilities of the latest matrix-assisted laser desorption/ionization (MALDI)-MSI technology for visualizing in situ metabolism of endogenous metabolites or dietary phytochemicals (food factors), and also discuss the technical problems and new challenges, including MALDI matrix selection and metabolite identification, that need to be addressed for effective and widespread application of MSI in the diverse fields of biological, biomedical, and nutraceutical (food functionality) research.

Fujimura, Yoshinori; Miura, Daisuke

2014-01-01

38

In situ XRF and gamma ray spectrometer for Mars sample return mission  

NASA Technical Reports Server (NTRS)

A combined in situ X-ray fluorescence (XRF) and passive gamma ray spectrometer instrument is proposed for the chemical elemental analysis of various Martian surfaces and samples. The combined instrument can be carried on board a rover. The passive gamma ray or the neutron excited gamma ray system would be used to determine the elemental composition of the Martian surface while the rover is in motion. The XRF system would be used to perform analysis either on the Martian surface or on collected samples when the rover is stationary. The latter function is important both in cataloging the collected samples and in the selection of samples to be returned to earth. For both systems, data accumulation time would be on the order of 30 minutes. No sample preparation would be necessary.

Lo, I. Yin; Trombka, Jacob I.; Evans, Larry G.; Squyres, Steven W.

1988-01-01

39

Standardisation of Gas Containers Used in gamma Spectrometry.  

National Technical Information Service (NTIS)

The diversity of gamma spectrometry applications brings out the need to standardise the conditioning of samples (gas-liquid, etc ....). Such standardisation leads to better suited and reproducible geometries but also to reduced costs and higher quality ca...

T. Pineira H. Goenvec

1986-01-01

40

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

NASA Astrophysics Data System (ADS)

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.

Mikesell, Jon L.; Dotson, Danny W.; Senftle, Frank E.; Zych, Richard S.; Koger, Joseph; Goldman, Leonard

1983-10-01

41

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

42

Technical considerations for using in situ gamma spectroscopy in conducting final status surveys.  

PubMed

Facilities undergoing decommissioning are required to conduct radiological surveys to initially characterize contaminants, guide remediation activities, and demonstrate that cleanup criteria have been met, based on screening or site-specific derived concentration guideline levels. This paper presents a number of technical considerations, not all inclusive, associated with the use of in situ gamma spectroscopy that should be addressed when such a method is proposed for conducting final status surveys. The technical issues identified here do not yet reflect the policy of the NRC on this subject. PMID:12792406

Dehmel, Jean-Claude; Schneider, Stewart

2003-06-01

43

Active Neutron and Gamma-Ray Instrumentation for In Situ Planetary Science Applications  

NASA Technical Reports Server (NTRS)

We describe the development of an instrument capable of detailed in situ bulk geochemical analysis of the surface of planets, moons, asteroids, and comets. This instrument technology uses a pulsed neutron generator to excite the solid materials of a planet and measures the resulting neutron and gamma-ray emission with its detector system. These time-resolved neutron and gamma-ray data provide detailed information about the bulk elemental composition, chemical context, and density distribution of the soil within 50 cm of the surface. While active neutron scattering and neutron-induced gamma-ray techniques have been used extensively for terrestrial nuclear well logging applications, our goal is to apply these techniques to surface instruments for use on any solid solar system body. As described, experiments at NASA Goddard Space Flight Center use a prototype neutron-induced gamma-ray instrument and the resulting data presented show the promise of this technique for becoming a versatile, robust, workhorse technology for planetary science, and exploration of any of the solid bodies in the solar system. The detection of neutrons at the surface also provides useful information about the material. This paper focuses on the data provided by the gamma-ray detector.

Parsons, A.; Bodnarik, J.; Evans, L.; Floyd, A.; Lim, L.; McClanahan, T.; Namkung, M.; Nowicki, S.; Schweitzer, J.; Starr, R.; Trombka, J.

2011-01-01

44

The Probing In-Situ With Neutron and Gamma Rays (PING) Instrument for Planetary Composition Measurements  

NASA Technical Reports Server (NTRS)

The Probing In situ with Neutrons and Gamma rays (PING) instrument (formerly named PNG-GRAND) [I] experiment is an innovative application of the active neutron-gamma ray technology successfully used in oil field well logging and mineral exploration on Earth over many decades. The objective of our active neutron-gamma ray technology program at NASA Goddard Space Flight Center (NASA/GSFC) is to bring PING to the point where it can be flown on a variety of surface lander or rover missions to the Moon, Mars, Venus, asteroids, comets and the satellites of the outer planets and measure their bulk surface and subsurface elemental composition without the need to drill into the surface. Gamma-Ray Spectrometers (GRS) have been incorporated into numerous orbital planetary science missions. While orbital measurements can map a planet, they have low spatial and elemental sensitivity due to the low surface gamma ray emission rates reSUlting from using cosmic rays as an excitation source, PING overcomes this limitation in situ by incorporating a powerful neutron excitation source that permits significantly higher elemental sensitivity elemental composition measurements. PING combines a 14 MeV deuterium-tritium Pulsed Neutron Generator (PNG) with a gamma ray spectrometer and two neutron detectors to produce a landed instrument that can determine the elemental composition of a planet down to 30 - 50 cm below the planet's surface, The penetrating nature of .5 - 10 MeV gamma rays and 14 MeV neutrons allows such sub-surface composition measurements to be made without the need to drill into or otherwise disturb the planetary surface, thus greatly simplifying the lander design, We are cun'ently testing a PING prototype at a unique outdoor neutron instrumentation test facility at NASA/GSFC that provides two large (1.8 m x 1.8 m x ,9 m) granite and basalt test formations placed outdoors in an empty field, Since an independent trace elemental analysis has been performed on both these Columbia River basalt and Concord Gray granite materials, these large samples present two known standards with which to compare PING's experimentally measured elemental composition results, We will present both gamma ray and neutron experimental results from PING measurements of the granite and basalt test formations in various layering configurations and compare the results to the known composition.

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

2012-01-01

45

Continuous Energy gamma-Ray Spectrometry.  

National Technical Information Service (NTIS)

Compton recoil gamma-ray spectroscopy provides absolute measurements of continuous gamma-ray spectra. Peaks which possess sufficient intensity above the continuum level can be observed. Since the inception of this spectrometric method, this method has evo...

R. Gold B. J. Kaiser J. P. McNeece

1983-01-01

46

In situ Analysis of Organic Compounds on Mars using Chemical Derivatization and Gas Chromatography Mass Spectrometry  

NASA Technical Reports Server (NTRS)

One of the core science objectives of NASA's 2009 Mars Science Laboratory (MSL) mission is to determine the past or present habitability of Mars. The search for key organic compounds relevant to terrestrial life will be an important part of that assessment. We have developed a protocol for the analysis of amino acids and carboxylic acids in Mars analogue materials using gas chromatography mass spectrometry (GCMS). As shown, a variety of carboxylic acids were readily identified in soil collected from the Atacama Desert in Chile at part-per-billion levels by GCMS after extraction and chemical derivatization using the reagent N,N-tert.-butyl (dimethylsilyl) trifluoroacetamide (MTBSTFA). Several derivatized amino acids including glycine and alanine were also detected by GCMS in the Atacama soil at lower concentrations (chromatogram not shown). Lacking derivatization capability, the Viking pyrolysis GCMS instruments could not have detected amino acids and carboxylic acids, since these non-volatile compounds require chemical transformation into volatile species that are stable in a GC column. We are currently optimizing the chemical extraction and derivatization technique for in situ GCMS analysis on Mars. Laboratory results of analyses of Atacama Desert samples and other Mars analogue materials using this protocol will be presented.

Glavin, D. P.; Buch, A.; Cabane, M.; Coll, P.; Navarro-Gonzalez, R.; Mahaffy, P. R.

2005-01-01

47

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

48

Time-resolved Neutron-gamma-ray Data Acquisition for in Situ Subsurface Planetary Geochemistry  

NASA Technical Reports Server (NTRS)

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

2013-01-01

49

MCNPX evaluation of gamma spectrometry results in high radon concentration areas.  

PubMed

The radon concentration in underground workplaces may reach tens of thousands of Bq m(-3). A simple MCNPX(TM) Monte Carlo (MC) model of a cave was developed to estimate the influence of radon on the in situ gamma spectrometry results in various geometries and radon concentrations. The detector total count rate was obtained as the sum of the individual count rates due to (214)Bi in the air, radon in the walls and deposition of radon daughters on surfaces. The MC model was then modified and used in the natural conditions of the Mlade? Caves, Czech Republic. The content of (226)Ra was calculated from laboratory gamma spectrometry measurements, and the concentrations of unattached and attached (214)Bi were measured using the FRITRA4 device (SMM-Prague). We present a comparison of the experimental results with results calculated by the MCNPX(TM) model of the Gamma Surveyor spectrometry probe (GF Instruments) with a 3? × 3? NaI(Tl) detector and a 2? × 2? BGO detector. PMID:24729561

Thinová, L; Solc, J

2014-07-01

50

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

51

Optimizing microarray-based in situ transcription–translation of proteins for matrix-assisted laser desorption ionization mass spectrometry  

Microsoft Academic Search

The analysis of self-assembled protein microarrays, using matrix-assisted laser desorption\\/ionization (MALDI) mass spectrometry, combines two high-throughput platforms for investigation of the proteome. In this article, we describe the fabrication in situ of protein arrays optimized for MALDI characterization. Using the green fluorescent protein (GFP) both as an epitope for immobilization and as a gauge for relative protein expression, we were

Michael J. Kimzey; Xristo Zarate; David W. Galbraith; Serrine S. Lau

2011-01-01

52

In situ cell-by-cell imaging and analysis of small cell populations by mass spectrometry.  

PubMed

Molecular imaging by mass spectrometry (MS) is emerging as a tool to determine the distribution of proteins, lipids, and metabolites in tissues. The existing imaging methods, however, mostly rely on predefined rectangular grids for sampling that ignore the natural cellular organization of the tissue. Here we demonstrate that laser ablation electrospray ionization (LAESI) MS can be utilized for in situ cell-by-cell imaging of plant tissues. The cell-by-cell molecular image of the metabolite cyanidin, the ion responsible for purple pigmentation in onion (Allium cepa) epidermal cells, correlated well with the color of cells in the tissue. Chemical imaging using single-cells as voxels reflects the spatial distribution of biochemical differences within a tissue without the distortion stemming from sampling multiple cells within the laser focal spot. Microsampling by laser ablation also has the benefit of enabling the analysis of very small cell populations for biochemical heterogeneity. For example, with a ?30 ?m ablation spot we were able to analyze 3-4 achlorophyllous cells within an oil gland on a sour orange (Citrus aurantium) leaf. To explore cell-to-cell variations within and between tissues, multivariate statistical analysis on LAESI-MS data from epidermal cells of an A. cepa bulb and a C. aurantium leaf and from human buccal epithelial cell populations was performed using the method of orthogonal projections to latent structures discriminant analysis (OPLS-DA). The OPLS-DA analysis of mass spectra, containing over 300 peaks each, provided guidance in identifying a small number of metabolites most responsible for the variance between the cell populations. These metabolites can be viewed as promising candidates for biomarkers that, however, require further verification. PMID:21388149

Shrestha, Bindesh; Patt, Joseph M; Vertes, Akos

2011-04-15

53

In situ digestion for the determination of Ca in beverages by tungsten coil atomic emission spectrometry.  

PubMed

Tungsten coil atomic emission spectrometry (WCAES) is employed for the determination of calcium in juice, mineral and coconut water samples. A sample aliquot of 20 ?L is placed directly on the coil and a constant-voltage power source is used to dry and atomize the sample, as well as to promote Ca atomic emission. Analytical signals are resolved and detected using a Czerny-Turner spectrometer and a charge coupled device detector. Some experimental parameters such as coil position related to the spectrometer entrance slit and integration time are critically evaluated. A heating program with relatively constant drying temperatures is used in all measurements. An in situ digestion procedure is used to partially decompose organic matrices and improve WCAES precision and accuracy. By adding an oxidizing mixture to the sample and including a digestion step in the heating cycle, no statistical difference was observed between WCAES and ICP OES results for Ca in juice and coconut water samples. Mineral water samples were simply diluted with 1% vv(-1) HNO(3) before analysis and no significant interference was observed for concomitants such as Na and K. Despite severe positive interference caused by Mg, good agreement was obtained between WCAES and ICP OES results for Ca in several mineral water samples. Limits of detection and quantification obtained were 0.02 and 0.07 mg L(-1), respectively. The method precision, calculated as the relative standard deviation for 10 consecutive measurements of a 2.5 mg L(-1) Ca solution, is 3.8%. PMID:22841081

Santos, Luana N; Gonzalez, Mário H; Moura, Monise F; Donati, George L; Nóbrega, Joaquim A

2012-08-15

54

Monte Carlo based calibration of scintillation detectors for laboratory and in situ gamma ray measurements.  

PubMed

The calibration of scintillation detectors for gamma radiation in a well characterized setup can be transferred to other geometries using Monte Carlo simulations to account for the differences between the calibration and the other geometry. In this study a calibration facility was used that is constructed from bricks of well-known activity concentrations of ??K and of radionuclides from the ²³?U- and ²³²Th-series. Transfer of the calibration was attempted to a Marinelli beaker geometry with the detector inside a lead shield and to an in situ application with the detector positioned on a sand bed. In general this resulted in good correspondence (within 5-10%) between the activity concentrations derived using the transferred calibration and activities that were derived by independent measurements. Some discrepancies were identified that were attributed to coincident summing in the natural decay series and interference of radon. PMID:21251733

van der Graaf, E R; Limburg, J; Koomans, R L; Tijs, M

2011-03-01

55

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

56

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

57

Detection of soil microorganism in situ by combined gas chromatography mass spectrometry  

NASA Technical Reports Server (NTRS)

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 carbon source, extended to include a variety of soils and additional substrates. In situ experiments were conducted without amendment using a vacuum sampling system.

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

1972-01-01

58

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

59

Medium-resolution Autonomous in situ Gamma Detection System for Marine and Coastal Waters  

SciTech Connect

We are developing a medium-resolution autonomous in situ gamma detection system for marine and coastal waters. The system is designed to extract and preconcentrate isotopes of interest from natural waters prior to detection in order to eliminate signal attenuation of the gamma rays traveling through water and lower the overall background due to the presence of naturally occurring radioactive isotopes (40K and U/Th series radionuclides). Filtration is used to preconcentrate target isotopes residing on suspended particles, while chemosorption is employed to preferentially extract truly dissolved components from the water column. A variety of commercial and in-house nano-porus chemosorbents have been selected, procured or produced, and tested. Used filter and chemosorbent media are counted autonomously using two LaBr3 detectors in a near 4-pi configuration around the samples. A compact digital pulse processing system developed in-house and capable of running in coincidence mode is used to process the signal from the detectors to a small on-board computer. The entire system is extremely compact (9” dia. x 30” len.) and platform independent, but designed for initial deployment on a research buoy.

Schwantes, Jon M.; Addleman, Raymond S.; Davidson, Joseph D.; Douglas, Matthew; Meier, David E.; Mullen, O Dennis; Myjak, Mitchell J.; Jones, Mark E.; Woodring, Mitchell L.; Johnson, Bryce; Santschi, Peter H.

2009-12-01

60

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

61

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/m 3 for the "old" depot, 214 Bq/m 3 for the "new" depot and 59 Bq/m 3 for the uncontaminated area and at the height of 1.5 m 20 Bq/m 3 for the "old" depot, 34 Bq/m 3 for the "new" depot and 26 Bq/m 3 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

62

Gamma-ray spectrometry in light-water-reactor environments  

SciTech Connect

To satisfy the needs of the Light Water Reactor Pressure Vessel Surveillance Dosimetry Improvement Program, differential and integral measurements have been in a light water reactor (LWR) pressure vessel simulator (PVS) at the poolside critical assembly (PAC) in Oak Ridge National Laboratory (ORNL). Within this framework, continuous gamma-ray spectrometry was carried out using Compton recoil gamma-ray spectroscopy. Advances in the state-of-the-art of this method are described with special emphasis given to the capabilities of the new Janus spectrometer. This new Janus spectrometer possessses many advantages and most notably extends the domain of continuous gamma-ray spectrometry up to roughly 6 MeV. Three different configurations of the LWR-PVS in the PCA have been studied.

Gold, R.; Kaiser, B.J.; McNeece, J.P.

1982-02-16

63

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

64

Monte Carlo simulation of in situ LaBr gamma-ray spectrometer for marine environmental monitoring.  

PubMed

Monte Carlo simulation of energy-response functions of gamma rays from natural/artificial radionuclides in seawater and simulation of energy spectrum due to self-activity in LaBr crystal were carried out using MCNPX codes and MATLAB programs for the in situ LaBr gamma-ray spectrometer immersed in homogeneous seawater. The effective detection distance, the detection efficiency and the minimum detectable activity concentration (MDAC) for artificial radionuclides (137)Cs were worked out as an instance. Similar researches for NaI detector was also implemented for comparison. The results indicate that the self-activity in LaBr deteriorates the MDAC to merely several times of that of NaI detector. The LaBr detector is possible to be used as in situ gamma-ray spectrometer for monitoring of artificial radionuclides in seawater. PMID:21613267

Su, Genghua; Zeng, Zhi; Cheng, Jianping

2011-07-01

65

A dedicated LIMS for routine gamma-ray spectrometry.  

PubMed

We developed a Microsoft(®) Access-based LIMS (Laboratory Information and Management Systems), ?-LIMS, for the management of our gamma-spectrometry laboratory, in which thousands of routine, but high-quality analyses are performed each year. This paper explains the main features of the ?-LIMS and puts special attention on the interfacing methods and solutions for using the Genie™2000 spectrometry software in conjunction with the EFFTRAN package, which serves for efficiency transfer calculations, coincidence summing corrections and a procedure for uncertainty estimation. PMID:24332338

Bruggeman, M; Verheyen, L; Vidmar, T

2014-05-01

66

A numerical method for the calibration of in situ gamma ray spectroscopy systems.  

PubMed

High purity germanium in situ gamma ray spectroscopy systems are typically calibrated using pre-calculated tables and empirical formulas to estimate the response of a detector to an exponentially distributed source in a soil matrix. Although this method is effective, it has estimated uncertainties of 10-15%, is limited to only a restricted set of measurement scenarios, and the approach only applies to an exponentially distributed source. In addition, the only soil parameters that can be varied are density and moisture content, while soil attenuation properties are fixed. This paper presents a more flexible method for performing such calibrations. For this new method, a three- or four-dimensional analytical expression is derived that is a combination of a theoretical equation and experimentally measured data. Numerical methods are used to integrate this expression, which approximates the response of a detector to a large variety of source distributions within any soil, concrete, or other matrix. The calculation method is flexible enough to allow for the variation of multiple parameters, including media attenuation properties and the measurement geometry. The method could easily be adapted to horizontally non-uniform sources as well. Detector responses are calculated analytically and Monte Carlo radiation transport simulations are used to verify the results. Results indicate that the method adds an uncertainty of only approximately 5% to the other uncertainties typically associated with the calibration of a detector system. PMID:20386196

Dewey, S C; Whetstone, Z D; Kearfott, K J

2010-05-01

67

Gamma-ray spectrometry of LDEF samples  

SciTech Connect

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 (sup 22)Na, {sup 46}Sc, {sup 51}Cr, {sup 54}Mn, {sup 56}Co, {sup 57}Co, {sup 58}Co, and {sup 60}Co. 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 {sup 7}Be on their leading surfaces. No significant {sup 7}Be 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%-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.

1991-12-31

68

Gamma-ray spectrometry of LDEF samples  

SciTech Connect

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 (sup 22)Na, {sup 46}Sc, {sup 51}Cr, {sup 54}Mn, {sup 56}Co, {sup 57}Co, {sup 58}Co, and {sup 60}Co. 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 {sup 7}Be on their leading surfaces. No significant {sup 7}Be 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%-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.

1991-01-01

69

Determination of environmental radiation flux and organ doses using in-situ gamma spectroscopy  

NASA Astrophysics Data System (ADS)

Contamination of buildings represent a unique problem during Decontamination and Decommissioning (D&D) of nuclear facilities. It is necessary to determine the long-lived radionuclides and their respective specific activities in building materials before the right D&D decision can be made. At the same time, radiation risk of workers or potential occupants in the facility must be assessed as part of the D&D process. The goal of this project was to develop a methodology of obtaining gamma radiation flux and organ doses from in-situ gamma spectroscopy. Algorithms were developed to simulate the response functions of the HPGe detector and to convert the spectra into photon fluences. A Monte Carlo code, MCNP4C, was used to simulate HPGe detector response and to develop the conversion algorithm. The simulated spectra obtained for an HPGe detector were converted to flux using the algorithm for various different geometries. The response functions of the detector are presented in this document for the gamma energies from 60 keV to 2.2 MeV. Published fluence-to-dose conversion coefficients were used to calculate organ doses and effective dose equivalent. We then tested the theory at a 100-MeV linear electron accelerator at Rensselaer Polytechnic Institute (RPI). Samples of the activated concrete walls and floor in the target room of the Linac facility as well as some steel samples were taken to quantify the specific activities of the structures. The results show that the most important long-lived radionuclides include 22 Na, 46Sc, 54 Mn, 57Co, 60 Co, 65Zn, 152 Eu and 154Eu, depending on the location and composition of the material. The specific activities at the Linac facility range from 1.15E-01 to 765.31 muCi/Kg. The annual effective dose equivalent was assessed to be 2.44 mSv y-1 (0.244 rem y-1 ), which is about 5% of the Annual EDE limits to workers.

Al-Ghamdi, Abdulrahman S.

70

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

71

In situ gamma spectroscopy measurement of 41Ar during neutron activation analysis with the SLOWPOKE II reactor in Jamaica.  

PubMed

In situ gamma spectroscopy was used to measure 41Ar released into the laboratory due to the activation of air in the irradiation tubes of SLOWPOKE reactor during routine neutron activation analysis. The data obtained were used to predict the 41Ar distribution in the laboratory for various operating conditions of the reactor. The dose received by the analyst from the immersion in 41Ar was calculated to be 2.36 microSv gamma(-1), which is approximately 1% of the normal background exposure. PMID:15551783

Grant, Charles N; Lalor, G C; Vutchkov, M K

2004-11-01

72

In situ high-temperature Raman study of crystalline nylon 6,12 fibers gamma-irradiated in argon atmosphere  

NASA Astrophysics Data System (ADS)

Samples of crystalline fibers of Nylon 6,12 gamma-irradiated under argon atmosphere were characterized by in situ high-temperature Raman spectroscopy. Identification of the most important Raman bands that characterize the nylon 6,12 is reported. In this study we show the effect of the preferred orientation of the crystals in the fiber on the Raman spectra, showing the Brill transition from triclinic to pseudo-hexagonal system. The stability of the crystalline fibers, which depends on the temperature as well as on the gamma-radiation applied, is another important result of this work.

Menchaca, C.; Manoun, B.; Martínez-Barrera, G.; Castaño, V. M.; López-Valdivia, H.

2006-09-01

73

The comparative effects of gamma radiation and in situ alpha particles on five strong-base anion exchange resins  

SciTech Connect

The effects of external gamma radiation and in situ alpha particles were measured on a recently available, macroporous, strong-base polyvinylpyridine resin and on four strong-base polystyrene anion exchange resins. Each resin was irradiated in 7 M nitric acid to 1--10 megaGray of gamma radiation from external {sup 60}Co, or to 5--14 megaGray of alpha particles from sorbed {sup 238}Pu. Each irradiated resin was measured for changes in dry weight, wet volume, weak-base and strong-base chloride exchange capacities, and exchange capacities for Pu(4) from nitric acid. Alpha-induced resin damage was significantly less than that caused by an equivalent dose of gamma radiation. The polyvinylpyridine resin offers the greatest resistance to damage from gamma radiation and from alpha particles. 5 refs., 1 figs. 5 tabs.

Marsh, S.F.

1991-01-01

74

Espectrometria Gama de Geometria 4 pi Infinita (Gamma Ray Spectrometry of Infinite 4 pi Geometry).  

National Technical Information Service (NTIS)

Because of the weak absorption of gamma radiation by matter, gamma-ray spectrometry may be applied to samples of great volume. A very interesting case is that of the gamma-ray spectrometry applied with 4-pi geometry around the detector on a sample assumed...

D. J. R. Nordemann

1987-01-01

75

Touch spray mass spectrometry for in situ analysis of complex samples.  

PubMed

Touch spray, a spray-based ambient in situ ionization method, uses a small probe, e.g. a teasing needle to pick up sample and the application of voltage and solvent to cause field-induced droplet emission. Compounds extracted from the microsample are incorporated into the sprayed micro droplets. Performance tests include disease state of tissue, microorganism identification, and therapeutic drug quantitation. Chemical derivatization is performed simultaneously with ionization. PMID:24756256

Kerian, Kevin S; Jarmusch, Alan K; Cooks, R Graham

2014-05-01

76

Tellurium speciation analysis using hydride generation in situ trapping electrothermal atomic absorption spectrometry and ruthenium or palladium modified graphite tubes.  

PubMed

Speciation of tellurium can be achieved by making use of different kinetic behaviors of Te(IV) and Te(VI) upon their reaction with sodium borohydride using hydride generation. While Te(IV) can form H(2)Te, Te(VI) will not form any volatile species during the course of hydride formation and measurement by atomic absorption spectrometry. Quantitative reduction of Te(VI) was achieved through application of a microwave assisted prereduction of Te(VI) in 6.0 mol/L HCl solution. Enhanced sensitivity was achieved by in situ trapping of the generated H(2)Te species in a previously heated graphite furnace whose surface was modified using Pd or Ru. Overall efficiency for in situ trapping in pyrolytically coated graphite tube surface was found to be 15% when volatile analyte species are trapped for 60s at 300°C. LOD and LOQ values were calculated as 0.086 ng/mL and 0.29 ng/mL, respectively. Efficiency was increased to 46% and 36% when Pd and Ru surface modifiers were used, respectively. With Ru modified graphite tube 173-fold enhancement was obtained over 180 s trapping period with respect to ETAAS; the tubes could be used for 250 cycles. LOD values were 0.0064 and 0.0022 ng/mL for Pd and Ru treated ETAAS systems, respectively, for 180 s collection of 9.6 mL sample solution. PMID:23182575

Yildirim, Emrah; Akay, P?nar; Arslan, Yasin; Bakirdere, Sezgin; Ataman, O Yavuz

2012-12-15

77

The Laser Ablation Ion Funnel: Sampling for in situ Mass Spectrometry on Mars  

NASA Technical Reports Server (NTRS)

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.

2011-01-01

78

Multiple-reflection time-of-flight mass spectrometry for in situ applications  

NASA Astrophysics Data System (ADS)

Multiple-reflection time-of-flight mass spectrometers (MR-TOF-MS) have recently been installed at different low-energy radioactive ion beam facilities. They are used as isobar separators with high ion capacity and as mass spectrometers with high mass resolving power and accuracy for short-lived nuclei. Furthermore, MR-TOF-MS have a huge potential for applications in other fields, such as chemistry, biology, medicine, space science, and homeland security. The development, commissioning and results of an MR-TOF-MS is presented, which serves as proof-of-principle to show that very high mass resolving powers (˜105) can be achieved in a compact device (length ˜30 cm). Based on this work, an MR-TOF-MS for in situ application has been designed. For the first time, this device combines very high mass resolving power (>105), mobility, and an atmospheric pressure inlet in one instrument. It will enable in situ measurements without sample preparation at very high mass accuracy. Envisaged applications of this mobile MR-TOF-MS are discussed.

Dickel, T.; Plaß, W. R.; Lang, J.; Ebert, J.; Geissel, H.; Haettner, E.; Jesch, C.; Lippert, W.; Petrick, M.; Scheidenberger, C.; Yavor, M. I.

2013-12-01

79

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

80

Basic characterization of highly enriched uranium by gamma spectrometry  

NASA Astrophysics Data System (ADS)

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 a low-background chamber was used. In addition, age dating of uranium was also performed using low-background spectrometry.

Nguyen, Cong Tam; Zsigrai, József

2006-05-01

81

Gamma ray spectrometry of LDEF samples at SRL  

NASA Technical Reports Server (NTRS)

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 spectrometry. 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 were reported to collect noticeable Be-7 on their leading surfaces. No significant Be-7 was detected in the samples analyzed.

Winn, Willard G.

1992-01-01

82

Gamma ray spectrometry of LDEF samples at SRS  

NASA Technical Reports Server (NTRS)

A total of 31 samples from Long Duration Exposure Facility (LDEF), including materials of Al, V, and steel trunnions were analyzed by ultralow level gamma spectrometry. 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 an end piece that collects noticeable Be-7 on its leading surface. No significant Be-7 was detected in the samples analyzed. The most sensitive analyses were performed with a 90 pct. efficient HPGe gamma ray detector, which is enclosed in a purged active/passive active shield.

Winn, Willard G.

1991-01-01

83

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

84

Development of the Probing In-Situ with Neutron and Gamma Rays (PING) Instrument for Planetary Science Applications  

NASA Technical Reports Server (NTRS)

The Probing In situ with Neutrons and Gamma rays (PING) instrument is a promising planetary science application of the active neutron-gamma ray technology that has been used successfully in oil field well logging and mineral exploration on Earth for decades. Similar techniques can be very powerful for non-invasive in situ measurements of the subsurface elemental composition on other planets. The objective of our active neutron-gamma ray technology program at NASA Goddard Space Flight Center (NASA/GSFC) is to bring instruments using this technology to the point where they can be flown on a variety of surface lander or rover missions to the Moon, Mars, Venus, asteroids, comets and the satellites of the outer planets. PING combines a 14 MeV deuterium-tritium pulsed neutron generator with a gamma ray spectrometer and two neutron detectors to produce a landed instrument that can determine the elemental composition of a planet down to 30 - 50 cm below the planet's surface. The penetrating nature of.5 - 10 MeV gamma rays and 14 MeV neutrons allows such sub-surface composition measurements to be made without the need to drill into or otherwise disturb the planetary surface, thus greatly simplifying the lander design. We are currently testing a PING prototype at a unique outdoor neutron instrumentation test facility at NASA/GSFC that provides two large (1.8 m x 1.8 m x.9 m) granite and basalt test formations placed outdoors in an empty field. Since an independent trace elemental analysis has been performed on both the Columbia River basalt and Concord Gray granite materials, these samples present two known standards with which to compare PING's experimentally measured elemental composition results. We will present experimental results from PING measurements of both the granite and basalt test formations and show how and why the optimum PING instrument operating parameters differ for studying the two materials.

Parsons, A.; Bodnarik, J.; Burger, D.; Evans, L.; Floyd, S; Lim, L.; McClanahan, T.; Namkung, M.; Nowicki, S.; Schweitzer, J.; Starr, R.; Trombka, J.

2011-01-01

85

Laser Ablation Electrodynamic Ion Funnel for In Situ Mass Spectrometry on Mars  

NASA Technical Reports Server (NTRS)

A front-end instrument, the laser ablation ion funnel, was developed, which would ionize rock and soil samples in the ambient Martian atmosphere, and efficiently transport the product ions into a mass spectrometer for in situ analysis. Laser ablation creates elemental ions from a solid with a high-power pulse within ambient Mars atmospheric conditions. Ions are captured and focused with an ion funnel into a mass spectrometer for analysis. The electrodynamic ion funnel consists of a series of axially concentric ring-shaped electrodes whose inside diameters (IDs) decrease over the length of the funnel. DC potentials are applied to each electrode, producing a smooth potential slope along the axial direction. Two radio-frequency (RF) AC potentials, equal in amplitude and 180 out of phase, are applied alternately to the ring electrodes. This creates an effective potential barrier along the inner surface of the electrode stack. Ions entering the funnel drift axially under the influence of the DC potential while being restricted radially by the effective potential barrier created by the applied RF. The net result is to effectively focus the ions as they traverse the length of the funnel.

Johnson, Paul V.; Hodyss, Robert P.; Tang, Keqi; Smith, Richard D.

2012-01-01

86

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

2013-03-25

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

Mass spectrometry imaging: an expeditious and powerful technique for fast in situ lignin assessment in Eucalyptus.  

PubMed

Plant biomass has been suggested as an alternative to produce bioethanol. The recalcitrance of plant biomass to convert cellulose into simpler carbohydrates used in the fermentation process is partially due to lignin, but the standard methods used to analyze lignin composition frequently use toxic solvents and are laborious and time-consuming. MS imaging was used to study lignin in Eucalyptus, since this genus is the main source of cellulose in the world. Hand-cut sections of stems of two Eucalyptus species were covered with silica and directly analyzed by matrix-assisted laser sesorption ionization (MALDI)-imaging mass spectrometry (MS). Information available in the literature about soluble lignin subunits and structures were used to trace their distribution in the sections and using a software image a relative quantification could be made. Matrixes routinely used in MALDI-imaging analysis are not satisfactory to analyze plant material and were efficiently substituted by thin layer chromatography (TLC) grade silica. A total of 22 compounds were detected and relatively quantified. It was also possible to establish a proportion between syringyl and guaiacyl monolignols, characteristic for each species. Because of the simple way that samples are prepared, the MALDI-imaging approach presented here can replace, in routine analysis, complex and laborious MS methods in the study of lignin composition. PMID:24451041

Araújo, Pedro; Ferreira, Mônica Siqueira; de Oliveira, Diogo Noin; Pereira, Luciano; Sawaya, Alexandra Christine Helena Frankland; Catharino, Rodrigo Ramos; Mazzafera, Paulo

2014-04-01

89

Environmental Gamma-Ray Exposure Rates Measured by In-Situ Ge(Li) Spectrometer  

Microsoft Academic Search

A conversion function (G(E) function) was determined to obtain an exposure rate directly from a ?-rays spectrum measured by an in-situ Ge(Li) spectrometer. In order to verify the utility of the G(E) function method, three kinds of detector, namely, a portable Ge(Li) detector, a Nal(Tl) detector and an ionization chamber, were used to measure exposure rate due to environmental ?-rays

Hiromi TERADA; Eiji SAKAI; Masaki KATAGIRI

1980-01-01

90

Planetary In Situ Sample Analysis with Tandem Two-Step Laser Mass Spectrometry  

NASA Astrophysics Data System (ADS)

Future surface missions to comets and outer solar system satellites such as Europa, Enceladus, and Titan will benefit strongly from investigations that can detect a wide range of organics in complex sample mixtures and ices, as well as determine the structure of selected molecules, to provide insight into their origin and evolution. At the same time, such missions are likely to be among the most highly constrained in mass and power resources, particularly those flown within the tightly focused Discovery and New Frontiers programs. Techniques requiring minimal or no sample manipulation or preparation may be needed to reduce complexity. Pulsed laser-based mass spectrometry may satisfy such requirements, with total instrument masses potentially less than 5 kg, particularly where analysis of higher-molecular weight, nonvolatile species is a priority objective. Prototype flight-compatible mass spectrometers under active development in our lab are based on direct ultraviolet Nd:YAG laser desorption and ionization (LDI) of solid samples under high vacuum. Prompt ions from a single few ns-duration laser pulse are accelerated into a compact time-of-flight mass spectrometer (TOF-MS). Both inorganic species including elements and oxides such as M_xO_y (M = Mg, Al, Cl, Ca, Fe; x, y = 1-4) from the mineral matrix as well as organics with molecular weights up to several kDa are readily detected over a range of laser intensities. To improve our ability to distinguish among peaks and patterns in the often-complex LDI spectra obtained from natural samples, we have recently begun systematically testing several critical instrument enhancements. First, by moving the common voltage bias of the ion flight tube and detector to a common negative potential, we are able to switch between positive and negative ion detection modes with only electrostatic switching. Inter-comparison of cation and anion spectra can provide highly diagnostic information on both inorganic (e.g., Na+ and K+ vs. Cl-) and organic moieties. Second, by focusing a separate "post-ionization" laser pulse just above the sample surface, we can achieve two-step laser mass spectrometry, or L2MS, in the same highly-miniaturized TOF-MS. L2MS enables selective analysis of aromatic organics even in the presence of a complex mineral matrix. Finally, by introducing an ion optical gate in the flight path, we are able to take advantage of the broad focusing capabilities of the "curved field" reflectron at the core of the TOF-MS to achieve pseudo-tandem structural analysis of selected organics. The high-speed gate is used to admit only the molecular ion/s of interest into the reflectron. Diagnostic fragments of the ion/s obtained through metastable decay or active collision-induced dissociation (CID) remain in focus despite having widely variable velocities and masses. As such even molecular isomers with differing fragmentation pathways may be distinguished through a series of pseudo-tandem mass spectra that could be obtained in an automatic process during a mission. The "real-world" benefits of these enhancements are being fully characterized using a set of synthetic and natural standard samples as well as several planetary analogs and meteorites.

Brinckerhoff, W. B.; Getty, S. A.; Cornish, T. J.; Ecelberger, S. A.; Li, X.; Merrill Floyd, M. A.; Arevalo, R.; Elsila, J.; Callahan, M. P.

2012-12-01

91

Waste Characterization Using Gamma Ray Spectrometry with Automated Efficiency Optimization - 13404  

SciTech Connect

Gamma ray spectrometry using High Purity Germanium (HPGe) detectors is commonly employed in assaying radioactive waste streams from a variety of sources: nuclear power plants, Department of Energy (DOE) laboratories, medical facilities, decontamination and decommissioning activities etc. The radioactive material is typically packaged in boxes or drums (for e.g. B-25 boxes or 208 liter drums) and assayed to identify and quantify radionuclides. Depending on the origin of the waste stream, the radionuclides could be special nuclear materials (SNM), fission products, or activation products. Efficiency calibration of the measurement geometry is a critical step in the achieving accurate quantification of radionuclide content. Due to the large size of the waste items, it is impractical and expensive to manufacture gamma ray standard sources for performing a measurement based calibration. For well over a decade, mathematical efficiency methods such as those in Canberra's In Situ Object Counting System (ISOCS) have been successfully employed in the efficiency calibration of gamma based waste assay systems. In the traditional ISOCS based calibrations, the user provides input data such as the dimensions of the waste item, the average density and fill height of the matrix, and matrix composition. As in measurement based calibrations, the user typically defines a homogeneous matrix with a uniform distribution of radioactivity. Actual waste containers can be quite nonuniform, however. Such simplifying assumptions in the efficiency calibration could lead to a large Total Measurement Uncertainty (TMU), thus limiting the amount of waste that can be disposed of as intermediate or low activity level waste. To improve the accuracy of radionuclide quantification, and reduce the TMU, Canberra has developed the capability to optimize the efficiency calibration using the ISOCS method. The optimization is based on benchmarking the efficiency shape and magnitude to the data available in the analyzed gamma ray spectra. Data from measurements of a given item in multiple counting geometries are among the powerful benchmarks that could be used in the optimization. Also, while assaying a waste stream with fission products and activation products emitting gamma lines of multiple energies, optimizing the efficiency on the basis of line activity consistency is very effective. In the present paper, the ISOCS- based optimization methodology is applied to measurement scenarios involving multiple counting geometries, and multi-gamma-line radionuclides. Results will be presented along with accuracy and precision estimates for each measurement. (authors)

Bosko, A.; Venkataraman, R.; Bronson, F.L.; Ilie, G.; Russ, W.R. [Canberra Industries, 800 Research Parkway, Meriden, CT 06450 (United States)] [Canberra Industries, 800 Research Parkway, Meriden, CT 06450 (United States)

2013-07-01

92

High-resolution gamma-ray spectrometry in uranium exploration  

USGS Publications Warehouse

Sedimentary-type uranium deposits accumulate at favorable sites along a migration path which may be kilometers in length. Their source is a large volume of rock from which the uranium has been leached. The geochemical mobilities and half lives of uranium and its daughter products vary widely so that they are transported from the source rocks, at different rates, along the migration path to their ultimate site. The radioactive disequilibrium resulting from this process has been well documented in the immediate vicinity of ore deposits, and disequilibrium is commonly recorded on gamma-ray logs up the hydraulic gradient from uranium ore. Little is known about the state of secular equilibrium in the leached host rocks, which often represent the only part of the migration path that is at or near the surface and is thus most accessible to the exploration geophysicist. High-resolution gamma-ray spectrometry provides a means of investigating the disequilibrium associated with uranium leaching and migration. Direct measurement of uranium can be made by this method, and the equivalent weight percents can be determined for six of the seven daughter-product decay groups that characterize the state of radioactive equilibrium. The technique has been used quantitatively in laboratory studies, where the results compare favorably with radiochemical analyses; field experiments suggest that semi-quantitative data may be obtained at the outcrop.

Moxham, Robert M.; Tanner, Allan B.

1977-01-01

93

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

94

Active Neutron and Gamma Ray Instrumentation for In Situ Planetary Science Applications  

NASA Technical Reports Server (NTRS)

The Pulsed Neutron Generator-Gamma Ray And Neutron Detectors (PNG-GRAND) experiment is an innovative application of the active neutron-gamma ray technology so successfully used in oil field well logging and mineral exploration on Earth. The objective of our active neutron-gamma ray technology program at NASA Goddard Space Flight Center (NASA-GSFC) is to bring the PNG-GRAND instrument to the point where it can be flown on a variety of surface lander or rover missions to the Moon, Mars, Menus, asteroids, comets and the satellites of the outer planets. Gamma-Ray Spectrometers (GRS) have been incorporated into numerous orbital planetary science missions and, especially its the case of the Mars Odyssey GRS, have contributed detailed maps of the elemental composition over the entire surface of Mars. However, orbital gamma ray measurements have low spatial sensitivity (100's of km) due to their low surface emission rates from cosmic rays and subsequent need to be averaged over large surface areas. PNG-GRAND overcomes this impediment by incorporating a powerful neutron excitation source that permits high sensitivity surface and subsurface measurements of bulk elemental compositions. PNG-GRAND combines a pulsed neutron generator (PNG) with gamma ray and neutron detectors to produce a landed instrument to determine subsurface elemental composition without needing to drill into a planet's surface a great advantage in mission design. We are currently testing PNG-GRAND prototypes at a unique outdoor neutron instrumentation test facility recently constructed at NASA/GSFC that consists of a 2 m x 2 in x 1 m granite structure placed outdoors in an empty field. Because an independent trace elemental analysis has been performed on the material, this granite sample is a known standard with which to compare both Monte Carlo simulations and our experimentally measured elemental composition data. We will present data from operating PNG-GRAND in various experimental configurations on a known sample in a geometry that is identical to that on a planetary surface. We will also illustrate the use of gamma ray timing techniques to improve sensitivity and will compare the material composition results from our experiments to both an independent laboratory elemental composition analysis and MCNPX computer modeling results.

Parsons, A.; Bodnarik, J.; Evans, L.; Floyd, S.; Lim, L.; McClanahan, T.; Namkung, M.; Schweitzer, J.; Starr, R.; Trombka, J.

2010-01-01

95

Basic characterization of 233U: Determination of age and 232U content using sector field ICP-MS, gamma spectrometry and alpha spectrometry  

NASA Astrophysics Data System (ADS)

The possibility to determine the age, i.e. the time since the last chemical separation, of 233U was studied using two fundamentally different measurement techniques: inductively coupled plasma mass spectrometry (ICP-MS) and gamma spectrometry. Moreover, the isotope ratio 232U/ 233U was measured using both alpha spectrometry and gamma spectrometry. For the two materials analysed, all measurement results were in agreement, i.e. consistent within the combined uncertainties. One of the materials was also measured using gamma spectrometry under field conditions. This measurement was also in agreement with the other results on this material.

Ramebäck, H.; Nygren, U.; Lagerkvist, P.; Verbruggen, A.; Wellum, R.; Skarnemark, G.

2008-03-01

96

A team approach to the development of gamma ray and x ray remote sensing and in situ spectroscopy for planetary exploration missions  

NASA Technical Reports Server (NTRS)

An important part of the investigation of planetary origin and evolution is the determination of the surface composition of planets, comets, and asteroids. Measurements of discrete line X-ray and gamma ray emissions from condensed bodies in space can be used to obtain both qualitative and quantitative elemental composition information. The Planetary Instrumentation Definition and Development Program (PIDDP) X-Ray/Gamma Ray Team has been established to develop remote sensing and in situ technologies for future planetary exploration missions.

Trombka, J. I.; Floyd, S.; Ruitberg, A.; Evans, L.; Starr, R.; Metzger, A.; Reedy, R.; Drake, D.; Moss, C.; Edwards, B.

1993-01-01

97

Analysis Software for gamma Spectrometry Developed on an IN96 Inter-Technique Multichannel Analyser.  

National Technical Information Service (NTIS)

An analysis software for gamma spectrometry has been developed and implemented on an INTERTECHNIQUE multichannel analyser (IN96). This software makes the analyser standard programs easier to use and gives solutions to several other analysis problems. Spec...

T. De Bruyne M. Silly A. Adam J. Laurec

1985-01-01

98

Applications of portable gamma-ray technologies to quantitative measurements in-situ  

SciTech Connect

Generalized-geometry models and methodologies for calibration and assay of nuclear material holdup in process equipment are described. Four important keys to success in satisfying portable measurement needs for inventory of nuclear materials are: improvements in compact, single, rugged, reliable instrumentation for gamma-ray spectroscopy; real-time automation; design and automation of generalized models and methods to satisfy multiple measurements needs; and real-time automation of data acquisition/analysis.

Bjork, C.W.; Russo, P.A.; Sheppard, G.A.; Smith, H.A.; Sprinkle, J.K. Jr. [Los Alamos National Lab., NM (United States); Smith, S.E. [Oak Ridge Y-12 Plant, TN (United States)

1993-09-01

99

Use of a Shielded High Resolution Gamma Spectrometry System to Segregate LLW from Contact Handleable ILW Containing Plutonium - 13046  

SciTech Connect

Dounreay Site Restoration Limited (DSRL) have a number of drums of solid waste that may contain Plutonium Contaminated Material. These are currently categorised as Contact Handleable Intermediate Level Waste (CHILW). A significant fraction of these drums potentially contain waste that is in the Low Level Waste (LLW) category. A Canberra Q2 shielded high resolution gamma spectrometry system is being used to quantify the total activity of drums that are potentially in the LLW category in order to segregate those that do contain LLW from CHILW drums and thus to minimise the total volume of waste in the higher category. Am-241 is being used as an indicator of the presence of plutonium in the waste from its strong 59.54 keV gamma-ray; a knowledge of the different waste streams from which the material originates allows a pessimistic waste 'fingerprint' to be used in order to determine an upper limit to the activities of the weak and non-gamma-emitting plutonium and associated radionuclides. This paper describes the main features of the high resolution gamma spectrometry system being used by DSRL to perform the segregation of CHILW and LLW and how it was configured and calibrated using the Canberra In-Situ Object Counting System (ISOCS). It also describes how potential LLW drums are selected for assay and how the system uses the existing waste stream fingerprint information to determine a reliable upper limit for the total activity present in each measured drum. Results from the initial on-site commissioning trials and the first measurements of waste drums using the new monitor are presented. (authors)

Lester, Rosemary; Wilkins, Colin [Canberra UK Ltd, Unit 1 B528.1, Harwell Science Campus, Oxfordshire OX11 0DF (United Kingdom)] [Canberra UK Ltd, Unit 1 B528.1, Harwell Science Campus, Oxfordshire OX11 0DF (United Kingdom); Chard, Patrick [Canberra UK Ltd, Forss Business and Technology park, Thurso, Caithness KW14 7UZ (United Kingdom)] [Canberra UK Ltd, Forss Business and Technology park, Thurso, Caithness KW14 7UZ (United Kingdom); Jaederstroem, Henrik; LeBlanc, Paul; Mowry, Rick [Canberra Industries, Inc., 800 Research Parkway, Meriden, Connecticut, 06450 (United States)] [Canberra Industries, Inc., 800 Research Parkway, Meriden, Connecticut, 06450 (United States); MacDonald, Sanders; Gunn, William [Dounreay Site Restoration Limited, Dounreay, Thurso, Caithness, KW14 7TZ (United Kingdom)] [Dounreay Site Restoration Limited, Dounreay, Thurso, Caithness, KW14 7TZ (United Kingdom)

2013-07-01

100

Dosimetrical analysis of reactor leakage gamma-rays by means of scintillation spectrometry  

Microsoft Academic Search

Exposure rates due to leakage gamma-rays from operating reactors TRIGA ; Mark II and III were measured in a horizontal plane by means of scintillation ; spectrometry using a 3'' x 3'' cylindrical NaI(Tl) detector associated with a 400 ; channel pulse height analyzer under varied conditions of reactor operation. In ; determining exposure rate due to the leakage gamma-rays

Jun

1973-01-01

101

Plutonium Isotopic Composition by gamma Spectrometry. A Code for Automatic Analysis.  

National Technical Information Service (NTIS)

This document describes an automatic analysis code for the measurement of plutonium isotopic composition by gamma spectrometry. This code is operational on a gamma analysis system (22 K Mots - 16 bits); it is used for the measurement of samples of differe...

J. Morel M. Vallee B. Chauvenet

1982-01-01

102

Recovery and reanalysis of archived airborne gamma spectrometry data from the 1991 Dounreay survey.  

PubMed

Archived Airborne Gamma Spectrometry (AGS) data from the 1991 NIREX characterisations of Caithness have been recovered. The separate gamma spectrometry and positional data streams for approximately 120,000 measurements have been combined into a single data stream using the European Radiometrics and Spectrometry (ERS) data format. An analysis using working calibration coefficients and spectral stripping procedure has verified that the original survey recorded high quality data. The converted data stream is in a format more accessible to future research use, including evaluation of environmental change in the Caithness region. PMID:21798750

Cresswell, A J

2012-01-01

103

In situ identification of organic components of ink used in books from the 1900s by atmospheric pressure matrix assisted laser desorption ionization mass spectrometry  

NASA Astrophysics Data System (ADS)

This paper describes the use of atmospheric pressure/matrix assisted laser desorption ionization-mass spectrometry (AP/MALDI-MS) as a spatially resolved analytical technique for the study of organic components of inks used to print coloured parts of ancient books. The possibility to operate at atmospheric pressure makes MALDI-MS a new in situ micro-destructive diagnostic tool suitable for analysing samples in air, simplifying the investigation of the organic components of artistic and archaeological objects. In this work, several organic dyes and pigments were identified in situ by analysing different coloured areas of books printed in the years 1911 and 1920. The detected colouring materials, which were available since the 1890s, were often identified as a mixture, confirming the typical procedures used in the lithographic printing processes. The matrix deposition and the laser desorption process did not cause visible alteration of the sample surface.

Giurato, Laura; Candura, Andrea; Grasso, Giuseppe; Spoto, Giuseppe

2009-11-01

104

Simultaneous analysis of benzophenone sunscreen compounds in water sample by stir bar sorptive extraction with in situ derivatization and thermal desorption–gas chromatography–mass spectrometry  

Microsoft Academic Search

A method for the simultaneous measurement of benzophenone (BP) sunscreen compounds, its derivatives 2,4-dihydroxybenzophenone (BP-1), 2-hydroxy-4-methoxybenzophenone (BP-3), 2-hydroxy-4-methoxy-4?-methylbenzophenone (BP-10), 2-hydroxybenzophenone (2OH-BP), 3-hydroxybenzophenone (3OH-BP) and 4-hydroxybenzophenone (4OH-BP), in water samples was developed using stir bar sorptive extraction (SBSE) with in situ derivatization followed by thermal desorption (TD)–gas chromatography–mass spectrometry (GC–MS). The detection limit is 0.5–2ngL?1 (ppt) for the seven BPs. The

Migaku Kawaguchi; Rie Ito; Hidehiro Honda; Naoyuki Endo; Noriya Okanouchi; Koichi Saito; Yasuo Seto; Hiroyuki Nakazawa

2008-01-01

105

Label-free in situ monitoring of histone deacetylase drug target engagement by matrix-assisted laser desorption ionization-mass spectrometry biotyping and imaging.  

PubMed

Measurements of target activation in cells or tissues are key indicators of efficacy during drug development. In contrast to established methods that require reagents and multiple preprocessing steps, reagent-free in situ analysis of engaged drug targets or target-proximal pharmacodynamic signatures in solid tumors remains challenging. Here, we demonstrate that label-free quantification of histone acetylation-specific mass shifts by matrix-assisted laser desorption ionization (MALDI) mass spectrometry biotyping can be used for measurement of cellular potency of histone deacetylase inhibitors in intact cells. Furthermore, we employ MALDI mass spectrometry imaging of these mass shifts to visualize the spatiotemporal distribution of acetylated histones and thus the tumor-selective pharmacodynamic responses in a mouse model of gasterointestinal cancer. Taken together, our study suggests that the monitoring of drug-induced mass shifts in protein ion intensity fingerprints or images may be a powerful analytical tool in pharmacology and drug discovery. PMID:24559101

Munteanu, Bogdan; Meyer, Björn; von Reitzenstein, Carolina; Burgermeister, Elke; Bog, Susanne; Pahl, Andreas; Ebert, Matthias P; Hopf, Carsten

2014-05-20

106

Comparison of gamma-ray coincidence and low-background gamma-ray singles spectrometry  

Microsoft Academic Search

Aerosol samples have been studied under different background conditions using gamma-ray coincidence and low-background gamma-ray singles spectrometric techniques with High-Purity Germanium detectors. Conventional low-background gamma-ray singles counting is a competitive technique when compared to the gamma–gamma coincidence approach in elevated background conditions. However, measurement of gamma–gamma coincidences can clearly make the identification of different nuclides more reliable and efficient than

J. Konki; P. T. Greenlees; U. Jakobsson; P. Jones; R. Julin; S. Juutinen; S. Ketelhut; K. Hauschild; R. Kontro; A.-P. Leppänen; A. Lopez-Martens; A. Mattila; P. Nieminen; M. Nyman; K. Peräjärvi; P. Peura; P. Rahkila; P. Ruotsalainen; J. Sarén; C. Scholey; J. Sorri; H. Toivonen; J. Turunen; J. Uusitalo

107

Determination of tributyltin in environmental water matrices using stir bar sorptive extraction with in-situ derivatisation and large volume injection-gas chromatography-mass spectrometry.  

PubMed

Stir bar sorptive extraction with in-situ derivatization using sodium tetrahydridoborate (NaBH4) followed by liquid desorption and large volume injection-gas chromatography-mass spectrometry detection under the selected ion monitoring mode (SBSE(NaBH4)in-situ-LD/LVI-GC-MS(SIM)) was successfully developed for the determination of tributyltin (TBT) in environmental water matrices. NaBH4 proved to be an effective and easy in-situ speciation agent for TBT in aqueous media, allowing the formation of adducts with enough stability and suitable polarity for SBSE analysis. Assays performed on water samples spiked at the 10.0?g/L, yielded convenient recoveries (68.2±3.0%), showed good accuracy, suitable precision (RSD<9.0%), low detection limits (23ng/L) and excellent linear dynamic range (r(2)=0.9999) from 0.1 to 170.0µg/L, under optimized experimental conditions. By using the standard addition method, the application of the present methodology to real surface water samples allowed very good performance at the trace level. The proposed methodology proved to be a feasible alternative for routine quality control analysis, easy to implement, reliable and sensitive to monitor TBT in environmental water matrices. PMID:24881528

Neng, N R; Santalla, R P; Nogueira, J M F

2014-08-01

108

Gamma spectrometry and plastic-scintillator inherent background  

SciTech Connect

The authors measured the energy resolution for a linear dependence of light yield on gamma radiation energy of gamma spectrometers based on plastic scintillation detectors for several plastic scintillators. If there were several gamma lines from the source the line with the highest energy was used to eliminate distortion due to overlap from the Compton background from gamma radiation of higher energy. Attenuation lengths were calculated. The tests were based on three modes of interaction between the gamma radiation and the scintillator: Compton scattering, the photoelectric effect, and pair formation. The contribution from light collection was also considered. The scintillators tested included polystyrene, polymethyl methacrylate, cesium iodide, and sodium iodide. Gamma sources included cesium 137, sodium 22, potassium 40, yttrium 88, thorium 232, and plutonium-beryllium.

Pomerantsev, V.V.; Gagauz, I.B.; Mitsai, L.I.; Pilipenko, V.S.; Solomonov, V.M.; Chernikov, V.V.; Tsirlin, Y.A.

1988-02-01

109

ADONIS, high count-rate HP-Ge {gamma} spectrometry algorithm: Irradiated fuel assembly measurement  

SciTech Connect

ADONIS is a digital system for gamma-ray spectrometry, developed by CEA. This system achieves high count-rate gamma-ray spectrometry with correct dynamic dead-time correction, up to, at least, more than an incoming count rate of 3.10{sup 6} events per second. An application of such a system at AREVA NC's La Hague plant is the irradiated fuel scanning facility before reprocessing. The ADONIS system is presented, then the measurement set-up and, last, the measurement results with reference measurements. (authors)

Pin, P. [AREVA NC La Hague - Nuclear Measurement Team, 50444 Beaumont-Hague Cedex (France); Barat, E.; Dautremer, T.; Montagu, T. [CEA - Saclay, LIST, Electronics and Signal Processing Laboratory, 91191 Gif sur Yvette (France); Normand, S. [CEA - Saclay, LIST, Sensors and Electronic Architectures Laboratory, 91191 Gif sur Yvette (France)

2011-07-01

110

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

Microsoft Academic Search

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 214Bi (1.76MeV), 208Tl (2.62MeV) and 40K (1.46MeV). The inferred absorbed dose rate

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

2009-01-01

111

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

112

The Mars Organic Molecule Analyser : in situ analysis of organic compounds on Mars by Gas Chromatography-Mass Spectrometry  

Microsoft Academic Search

The search for signs of past or present life is one of the primary goals of the future Mars exploratory missions. With this aim the Mars Organic Molecule Analyzer (MOMA) experiment of the ExoMars 2016-2018 next coming joint ESA\\/NASA mission is designed to perform the in situ analysis of exobiological organic molecules of exobiological interest in the Martian soil such

Arnaud Buch; Robert Sternberg; Caroline Freissinet; Veronika Pinnick; Cyril Szopa; Patrice Coll; Claude Geffroy-Rodier; Francois Raulin; Fred Goesmann

2010-01-01

113

A non-destructive method to determine the depth of radiological contamination in any material using gamma spectroscopy in-situ  

NASA Astrophysics Data System (ADS)

A non-destructive method based on in-situ gamma spectroscopy is developed to determine the depth of radiological contamination in media. An innovative algorithm, G&barbelow;amma P&barbelow;enetration ?epth U&barbelow;nfolding A&barbelow;lgorithm (GPDUA), uses point kernel techniques to determine the depth of contamination based on the results of the uncollided peak information from the in-situ gamma spectroscopy. The GPDUA is developed and verified through Monte Carlo simulations and validated through experiments. This innovative tool promises to be "better, faster, safer, and cheaper" than the current practice in the Department of Energy (DOE) for decontamination and decommissioning (D&D). The applicable radiological contaminants of interest are any isotopes that emit two or more gamma rays per disintegration or any single gamma-emitting isotope with progeny in stable equilibrium. The predicted depths from the GPDUA algorithm using Monte Carlo N-Particle Transport Code Version 4B (MCNP) simulations and experiment results have produced an average percent discrepancy of 3.7% between the predicted and the actual depth of contamination.

Naessens, Edward Paul

114

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

115

Latent transforming growth factor beta1 activation in situ: quantitative and functional evidence after low-dose gamma-irradiation  

NASA Technical Reports Server (NTRS)

The biological activity of transforming growth factor beta1 (TGF-beta) is controlled by its secretion as a latent complex in which it is noncovalently associated with latency-associated peptide (LAP). Activation is the extracellular process in which TGF-beta is released from LAP, and is considered to be a primary regulatory control. We recently reported rapid and persistent changes in TGF-beta immunoreactivity in conjunction with extracellular matrix remodeling in gamma-irradiated mouse mammary gland. Our hypothesis is that these specific changes in immunoreactivity are indicative of latent TGF-beta activation. In the present study, we determined the radiation dose response and tested whether a functional relationship exists between radiation-induced TGF-beta and collagen type III remodeling. After radiation exposures as low as 0.1 Gy, we detected increased TGF-beta immunoreactivity in the mammary epithelium concomitant with decreased LAP immunostaining, which are events consistent with activation. Quantitative image analysis demonstrated a significant (P=0.0005) response at 0.1 Gy without an apparent threshold and a linear dose response to 5 Gy. However, in the adipose stroma, loss of LAP demonstrated a qualitative threshold at 0.5 Gy. Loss of LAP paralleled induction of collagen III immunoreactivity in this tissue compartment. We tested whether TGF-beta mediates collagen III expression by treating animals with TGF-beta panspecific monoclonal antibody, 1D11.16, administered i.p. shortly before irradiation. Radiation-induced collagen III staining in the adipose stroma was blocked in an antibody dose-dependent manner, which persisted through 7 days postirradiation. RNase protection assay revealed that radiation-induced elevation of total gland collagen III mRNA was also blocked by neutralizing antibody treatment. These data provide functional confirmation of the hypothesis that radiation exposure leads to latent TGF-beta activation, support our interpretation of the reciprocal shift in immunoreactivity as evidence of activation, and implicate TGF-beta as a mediator of tissue response to ionizing radiation. The sensitivity of activation to low radiation doses points to a potential role for TGF-beta in orchestrating tissue response to oxidative stress. As such, radiation may be useful as a probe to delineate the consequences of latent TGF-beta activation in situ.

Ehrhart, E. J.; Segarini, P.; Tsang, M. L.; Carroll, A. G.; Barcellos-Hoff, M. H.; Chatterjee, A. (Principal Investigator)

1997-01-01

116

Photo-rheometry\\/NIR spectrometry: An in situ technique for monitoring conversion and viscoelastic properties during photopolymerization  

Microsoft Academic Search

A suitable rheometer for simultaneous dynamic mechanical analysis (DMA)\\u000a and NIR (Near Infra-Red) in situ 1 analysis during UV curing was\\u000a developed. The conversion and viscoelastic properties of a\\u000a dimethacrylate\\/styrene-based system were investigated. The results were\\u000a plotted against both it-radiation time and total, average conversion.\\u000a For the same conversion, a lower intensity delays the reaction but does\\u000a not affect the

Aurélie Botella; Jérôme Dupuy; Alain-André Roche; Henry Sautereau; Vincent Verney

2004-01-01

117

Sensitivity improvement for antimony determination by using in-situ atom trapping in a slotted quartz tube and flame atomic absorption spectrometry  

NASA Astrophysics Data System (ADS)

Significant improvement has been achieved for antimony determination using a slotted quartz tube (SQT) as an atom trap (AT) for in situ preconcentration and flame atomic absorption spectrometry (FAAS). The suggested technique consists of trapping analyte species during ordinary nebulization followed by releasing the collected analyte via introducing organic solvent. Procedures and analytical figures of merit have been presented for the techniques called FAAS, SQT-FAAS and finally SQT-AT-FAAS with the relevant comparisons. Analytical parameters, namely composition of the aqueous medium, sample flow rate, flame conditions, distance between burner head and SQT, sampling period and type of organic solvent and its volume have been optimized. Using SQT-AT-FAAS, a sensitivity enhancement of 369 fold has been obtained, 3 s limit of detection was 3.9 ?g L- 1 when 25.0 mL of sample was collected in 4.0 min. Interference effects of some elements on antimony signal were studied.

Titretir, Serap; ??k, Ahmet ?nanç; Arslan, Yasin; Ataman, O. Yavuz

2012-11-01

118

Simultaneous analysis of benzophenone sunscreen compounds in water sample by stir bar sorptive extraction with in situ derivatization and thermal desorption-gas chromatography-mass spectrometry.  

PubMed

A method for the simultaneous measurement of benzophenone (BP) sunscreen compounds, its derivatives 2,4-dihydroxybenzophenone (BP-1), 2-hydroxy-4-methoxybenzophenone (BP-3), 2-hydroxy-4-methoxy-4'-methylbenzophenone (BP-10), 2-hydroxybenzophenone (2OH-BP), 3-hydroxybenzophenone (3OH-BP) and 4-hydroxybenzophenone (4OH-BP), in water samples was developed using stir bar sorptive extraction (SBSE) with in situ derivatization followed by thermal desorption (TD)-gas chromatography-mass spectrometry (GC-MS). The detection limit is 0.5-2 ng L(-1) (ppt) for the seven BPs. The method shows good linearity and the correlation coefficients are equal to or higher than 0.990 for all the analyte. The average recoveries of BPs range from 102.0 to 128.1% (RSD<15.4%, n=6). Trace amounts of BPs in river water samples were determined by the present method. PMID:18550077

Kawaguchi, Migaku; Ito, Rie; Honda, Hidehiro; Endo, Naoyuki; Okanouchi, Noriya; Saito, Koichi; Seto, Yasuo; Nakazawa, Hiroyuki

2008-07-25

119

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

120

Development and calibration of a real-time airborne radioactivity monitor using direct gamma-ray spectrometry with two scintillation detectors.  

PubMed

The implementation of in-situ gamma-ray spectrometry in an automatic real-time environmental radiation surveillance network can help to identify and characterize abnormal radioactivity increases quickly. For this reason, a Real-time Airborne Radioactivity Monitor using direct gamma-ray spectrometry with two scintillation detectors (RARM-D2) was developed. The two scintillation detectors in the RARM-D2 are strategically shielded with Pb to permit the separate measurement of the airborne isotopes with respect to the deposited isotopes.In this paper, we describe the main aspects of the development and calibration of the RARM-D2 when using NaI(Tl) or LaBr3(Ce) detectors. The calibration of the monitor was performed experimentally with the exception of the efficiency curve, which was set using Monte Carlo (MC) simulations with the EGS5 code system. Prior to setting the efficiency curve, the effect of the radioactive source term size on the efficiency calculations was studied for the gamma-rays from (137)Cs. Finally, to study the measurement capabilities of the RARM-D2, the minimum detectable activity concentrations for (131)I and (137)Cs were calculated for typical spectra at different integration times. PMID:24607535

Casanovas, R; Morant, J J; Salvadó, M

2014-07-01

121

Direct determination of silicon in powdered aluminium oxide by use of slurry sampling with in situ fusion graphite-furnace atomic-absorption spectrometry.  

PubMed

A direct method for determination of silicon in powdered high-purity aluminium oxide samples, by slurry sampling with in situ fusion graphite-furnace atomic-absorption spectrometry (GF-AAS), has been established. A slurry sample was prepared by 10-min ultrasonication of a powdered sample in an aqueous solution containing both sodium carbonate and boric acid as a mixed flux. An appropriate portion of the slurry was introduced into a pyrolytic graphite furnace equipped with a platform. Silicon compounds to be determined and aluminium oxide were fused by the in situ fusion process with the flux in the furnace under optimized heating conditions, and the silicon absorbance was then measured directly. The calibration curve was prepared by use of a silicon standard solution containing the same concentration of the flux as the slurry sample. The accuracy of the proposed method was confirmed by analysis of certified reference materials. The proposed method gave statistically accurate values at the 95% confidence level. The detection limit was 3.3 microg g(-1) in solid samples, when 300 mg/20 mL slurry was prepared and a 10 microL portion of the slurry was measured. The precision of the determination (RSD for more than four separate determinations) was 14% and 2%, respectively, for levels of 10 and 100 microg g(-1) silicon in aluminium oxide. PMID:11569864

Minami, H; Yoshida, T; Okutsu, K; Zhang, Q; Inoue, S; Atsuya, I

2001-08-01

122

Gamma dose rate calculation and mapping of piemonte (North-West Italy) from gamma spectrometry soil data.  

PubMed

In this study the air gamma dose rate map of Piemonte, a region in the North-West of Italy, was produced from gamma spectrometry soil data. Soil samples collected in 110 different sites of Piemonte were analysed with Hyperpure Germanium (HPGe) detectors (30% relative efficiency), which allow the evaluation of the activity concentrations of natural radionuclides and (137)Cs. Then, using the available mathematical models, the gamma absorbed dose rate in air due to radionuclides was calculated. The contribution of the cosmic radiation to the total absorbed dose rate, which depend on the site altitude was also evaluated and added to the soil contribution. Finally, the map of the whole region was obtained by fitting the dose rate values of the different sites with kriging algorithms. PMID:15550714

Losana, M C; Magnoni, M; Bertino, S; Procopio, S; Facchinelli, A; Sacchi, E

2004-01-01

123

Cadium-Zinc-Telluride (CZT) Gamma Ray Spectrometry  

Microsoft Academic Search

This report describes CZT crystals and their use in large arrays for generation of gamma ray spectra. Laboratory spectra will be shown together with spectra accumulated by various battery powered portable instruments (see Appendix A). One of these portable instruments was specifically constructed to minimize power consumption and yet provide reasonable isotope identification capability. Detailed data will be presented covering

William Quam

2001-01-01

124

Some applications of gamma absorptiometry and spectrometry for the control of nuclear materials  

NASA Astrophysics Data System (ADS)

In nuclear fuels, and neutrons absorbers used in control rods, the thermal power generated is locally dependent on the concentration of the fissile or absorbing nucleus. In order to control the homogeneity of such materials, non-destructive methods using either gamma absorptiometry or gamma spectrometry were developed; some applications of these methods are presented in this paper. The fuel of the High Temperature Reactor (HTR) is frequently composed of UO 2 and ThO 2 spherical particles dispersed in a carbon matrix; the axial distribution of the particles along the fuel rods can be controlled in two ways: with gamma absorptiometry the heavy elements atoms (U+Th) can be detected but without discrimination between U and Th; with gamma spectrometry, separate distributions of uranium and thorium, deduced from the intensity of characteristic gamma rays are obtained. In nuclear power plants (PWR, FBR) the control rods are made usually with boron carbide (B 4C) pellets. By mean of gamma absorptiometry scanning the density distribution along the axis and the radius of the pellets are obtained. The originality of the method consists in the use of a self-calibration process, then the knowledge of the mass absorption coefficient is not required to perform the examinations. A computerized apparatus has been developed for these controls.

Guery, M.

1991-02-01

125

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

126

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

127

Well Ge and semi-planar Ge (HP) detectors for low-level gamma-spectrometry  

NASA Astrophysics Data System (ADS)

Two gamma spectrometers, a well Ge and a semi-planar Ge (HP), are now installed and calibrated for measurements of environmental radioactivity with special attention being paid to the requirements needed for aquatic mass-balance studies, including isotope-particle dynamics and dating of recent deposits. These facilities will complement the previously developed isotope dilution alpha spectrometry (PIPS detectors) and radon emanation (ionization chambers) techniques for 210Pb dating. A careful evaluation of efficiencies and background of the Ge detectors, together with the influence of the sample's intrinsic activity on the lower limit of detection (LLD), allowed us to study the relative importance of detector and shield specifications on low level gamma spectrometry of environmental samples with various sizes and composition.

El-Daoushy, F.; Garcia-Tenorio, R.

1995-02-01

128

Rapid and simultaneous in situ assessment of aflatoxins and stilbenes using silica plate imprinting mass spectrometry imaging.  

PubMed

A fast and direct combination of techniques for simultaneous mycotoxin and phytoalexin identification in peanut skin and kernel is described. Silica Plate Imprinting Laser Desorption/Ionization Mass Spectrometry Imaging (SPILDI-MSI) is a powerful technique that exhibits great advantages, such as solvent-free and matrix-free characteristics, as well as no sample preparation or separation steps. It also permits accurate identification of mycotoxins and phytoalexins with unique fingerprint profiles in just a few seconds. Results are expressed as chemical images of the 4 identified types of aflatoxins (B1, B2, G1 and G2) and a stilbenoid (resveratrol). Also, SPILDI-MSI allows the comparison between the spatial distribution of aflatoxins and resveratrol found in kernel and skin. This novel application has proven to be useful for instantaneous qualitative assessment of aflatoxins and stilbenoids both in the peanut skin and kernel and offers precise tracking of fungal contamination in nuts and other foodstuffs. PMID:24595464

de Oliveira, Diogo N; Ferreira, Mônica S; Catharino, Rodrigo R

2014-01-01

129

Stir bar sorptive extraction with in situ de-conjugation and thermal desorption gas chromatography-mass spectrometry for measurement of 4-nonylphenol glucuronide in human urine sample.  

PubMed

4-Nonylphenol glucuronide (NP-G) in human urine samples was analyzed using stir bar sorptive extraction (SBSE) with in situ de-conjugation by beta-glucuronidase and thermal desorption (TD)-gas chromatography-mass spectrometry (GC-MS). Distilled water (1 ml), 1.0 M ammonium acetate solution (100 microl) and beta-glucuronidase (10,000 units ml(-1), 10 microl) were added to human urine sample (1 ml), and extraction was commenced for 90 min at 37 degrees C while stirring at 250 rpm with a stir bar coated with a 500-microm-thick polydimethylsiloxane (PDMS) layer. Then, the stir bar was subjected to TD-GC-MS in the selected ion monitoring (SIM) mode. The calibration curve was made by SBSE method using 4-nonylphenol (NP) as the standard solution. The method showed good linearity and the correlation coefficients were 0.999 over the concentration range of 5-500 nM. Moreover, to optimize the conditions for SBSE with in situ de-conjugation and the recovery test, NP-G was synthesized by a biochemical technique in our laboratory. The limits of detection (S/N = 3) and quantitation (S/N > 10) for NP were 0.2 ng ml(-1) (1.0 nM) and 1.1 ng ml(-1) (5.0 nM), respectively. The average recoveries in the human urine samples (n = 6) spiked with NP-G at levels of 20 and 100 nM were 104.1 (R.S.D. 7.1%) and 100.6% (R.S.D. 9.2%), respectively, with correction using the added internal standard, 4-(1-methyl) octylphenol-d(5). The method enabled the precise determination of the standard and was applicable to the detection of trace amounts of NP-G in human urine samples. PMID:16019181

Kawaguchi, Migaku; Ito, Rie; Hayatsu, Yoshio; Nakata, Hisao; Sakui, Norihiro; Okanouchi, Noriya; Saito, Koichi; Yokota, Hiroshi; Izumi, Shun-ichiro; Makino, Tsunehisa; Nakazawa, Hiroyuki

2006-01-23

130

Correction for radon distribution in solid/liquid and air phases in gamma-ray spectrometry.  

PubMed

The effect of radon diffusion and distribution between a (226)Ra matrix and the top air gap inside sample containers for gamma-ray spectrometry was studied. Containers filled at almost 100% or just 70% of total capacity yielded correction factors of about 7% and 20% respectively. Applying these correction factors allowed activity values calculated from (226)Ra or radon decay products to agree within 2%. PMID:22476014

Carconi, P; Cardellini, F; Cozzella, M L; De Felice, P; Fazio, A

2012-09-01

131

Epithermal neutron activation analysis of uranium by neptunium-239 using high resolution gamma-spectrometry  

Microsoft Academic Search

The possibility to use the most intensive gamma-peak of239Np for INAA of uranium with epithermal neutrons and high resolution Ge(Li)-spectrometry is evaluated. A way for calculation\\u000a of the peak area of overlapping peaks of153Sm and239Np is proposed. This can be used in other similar cases in the practice of NAA. On this basis a scheme for NAA of uranium\\u000a in

I. Kuleff; K. Kostadinov

1981-01-01

132

gamma. -ray spectrometry for determination of radium-228 and radium-226 in natural waters  

Microsoft Academic Search

A technique has been developed for the measurement of ²²⁸Ra and ²²⁶Ra in both fresh- and seawater using Ge(Li) ..gamma..-ray spectrometry. Radium isotopes are preconcentrated in the field from 100 to 1000 L onto Mn-impregnated acrylic fiber cartridges, leached from the fiber and coprecipitated with BaSOâ. Lower limits of detection are controlled by the volume of water processed through the

Jacqueline. Michel; Willard S. Moore; Philip T. King

1981-01-01

133

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

134

NMIS With Gamma Spectrometry for Attributes of Pu and HEU, Explosives and Chemical Agents  

SciTech Connect

The concept for the system described herein is an active/passive Nuclear Materials Identification System{sup 2} (NMIS) that incorporates gamma ray spectrometry{sup 3}. This incorporation of gamma ray spectrometry would add existing capability into this system. This Multiple Attribute System can determine a wide variety of attributes for Pu and highly enriched uranium (HEU) of which a selected subset could be chosen. This system can be built using commercial off the shelf (COTS) components. NMIS systems are at All-Russian Scientific Research Institute of Experimental Physics (VNIIEF) and Russian Federal Nuclear Center Institute of Technical Physics, (VNIITF) and measurements with Pu have been performed at VNIIEF and analyzed successfully for mass and thickness of Pu. NMIS systems are being used successfully for HEU at the Y-12 National Security Complex. The use of active gamma ray spectrometry for high explosive HE and chemical agent detection is a well known activation analysis technique, and it is incorporated here. This report describes the system, explains the attribute determination methods for fissile materials, discusses technical issues to be resolved, discusses additional development needs, presents a schedule for building from COTS components, and assembly with existing components, and discusses implementation issues such as lack of need for facility modification and low radiation exposure.

Mihalczo, J. T.; Mattingly, J. K.; Mullens, J. A.; Neal, J. S.

2002-05-10

135

Use of liquid chromatography/tandem mass spectrometry to detect distinctive indicators of in situ RDX transformation in contaminated groundwater.  

PubMed

An important element of monitored natural attenuation is the detection in groundwater of distinctive products of pollutant degradation or transformation. In this study, three distinctive products of the explosive RDX (hexahydro-1,3,5-trinitro-1,3,5-triazine) were detected in contaminated groundwater from the Iowa Army Ammunition Plant; the products were MNX (hexahydro-1-nitroso-3,5-dinitro-1,3,5-triazine), DNX (hexahydro-1,3-dinitroso-5-nitro-1,3,5-triazine), and TNX (hexahydro-1,3,5-trinitroso-1,3,5-triazine). These compounds are powerful indicators of RDX transformation for several reasons: (a) they have unique chemical features that reveal their origin as RDX daughter products, (b) they have no known commercial, industrial, or natural sources, and (c) they are well documented as anaerobic RDX metabolites in laboratory studies. The products were analyzed by LC/MS/MS (liquid chromatography/mass spectrometry/mass spectrometry) with selected reaction monitoring and internal standard quantification using [ring-U-15N]RDX. Validation tests showed the novel LC/MS/MS method to be of favorable sensitivity (detection limits ca. 0.1 microg/L), accuracy, and precision. The products, which were detected in all groundwater samples with RDX concentrations of > ca. 1 microg/L (25 out of 55 samples analyzed), were present at concentrations ranging from near the detection limit to 430 microg/L. MNX was the typically the most abundant of the three nitroso-substituted products; concentrations of the products seldom exceeded 4 mol % of the RDX concentration, although they ranged as high as 26 mol % (TNX). Geographic and temporal distributions of RDX, MNX, DNX, and TNX were assessed. A degradation product resulting from RDX ring cleavage, methylenedinitramine, was not detected by LC/MS/MS in any sample (detection limit ca. 0.6-4 microg/L). This extensive field characterization of MNX, DNX, and TNX distributions in groundwater by a highly selective analytical method (LC/MS/MS) is significant because very little is known about the occurrence of intrinsic RDX transformation in contaminated aquifers. PMID:12026993

Beller, Harry R; Tiemeier, Kevin

2002-05-01

136

Cadium-Zinc-Telluride (CZT) Gamma Ray Spectrometry  

SciTech Connect

This report describes CZT crystals and their use in large arrays for generation of gamma ray spectra. Laboratory spectra will be shown together with spectra accumulated by various battery powered portable instruments (see Appendix A). One of these portable instruments was specifically constructed to minimize power consumption and yet provide reasonable isotope identification capability. Detailed data will be presented covering gamma energy resolution, gamma peak shapes, system background, and detector efficiency. Nearly all data were taken with very small crystals of CZT; cubes 5 mm on a side. A few spectra will be presented from cylindrical crystals of about the same size (see Appendix A). The small crystal size leads to low counting rates and extended counting times for reliable isotope identification. We have addressed this problem by using arrays of CZT crystals, initially two crystals and, at present, arrays of eight crystals. Data will be shown relating spectral parameters for these two arrays. System MDA is one way of combining resolution, efficiency, and background that will enable direct comparison of various detector types for individual isotope identification. We have calculated the MDA for an early dual crystal array and the current eight crystal array. Data derived from each array will be presented. In addition, it is possible to extrapolate the MDA methodology to much larger arrays. A 32-crystal array is under construction and extrapolations to 256 and 1024 crystals are considered possible. Estimated MDA values for these larger arrays are also presented. Several 8-crystal arrays have been constructed and versions have been incorporated into portable instruments. Descriptions of these small instruments are given covering physical size, weight, and general configuration. These instruments have been tested for shock and temperature effects and data will be presented on the results of these tests. The MDA concept will also allow extrapolation to large source to detector distances. The usual laboratory measurements are done with small sources at 20 to 50 cm ranges. Practical ranges for aerial work will be 50 to 100 meters or greater. These distances will require correction for air attenuation for most of the low energy isotopes. The approximations used in the present note for aerial measurements involve small diameter sources (diameter approximately equal to the altitude), a 1 kt pass, and a planar array with no aircraft attenuation material in the field of view. The array will have a collimator to limit the side-looking sensitivity to enable a more accurate extrapolation from the laboratory data. Large arrays will have significant physical size and weight compared to the small hand-held instruments thus far constructed. We estimate these parameters and extrapolate the power consumption to provide a realistic estimate of a suitable airborne system. In all cases these larger systems are lighter and physically more compact than the usual NaI or high purity Germanium (HPGe) systems used in aerial work. Thus deployment should be simple. The power consumption is much less as well.

William Quam

2001-09-01

137

Determination of methylmercury by electrothermal atomic absorption spectrometry using headspace single-drop microextraction with in situ hydride generation  

NASA Astrophysics Data System (ADS)

A new method is proposed for preconcentration and matrix separation of methylmercury prior to its determination by electrothermal atomic absorption spectrometry (ETAAS). Generation of methylmercury hydride (MeHgH) from a 5-ml solution is carried out in a closed vial and trapped onto an aqueous single drop (3-?l volume) containing Pd(II) or Pt(IV) (50 and 10 mg/l, respectively). The hydrogen evolved in the headspace (HS) after decomposition of sodium tetrahydroborate (III) injected for hydride generation caused the formation of finely dispersed Pd(0) or Pt(0) in the drop, which in turn, were responsible for the sequestration of MeHgH. A preconcentration factor of ca. 40 is achieved with both noble metals used as trapping agents. The limit of detection of methylmercury was 5 and 4 ng/ml (as Hg) with Pd(II) or Pt(IV) as trapping agents, and the precision expressed as relative standard deviation was about 7%. The preconcentration system was fully characterised through optimisation of the following variables: Pd(II) or Pt(IV) concentration in the drop, extraction time, pH of the medium, temperatures of both sample solution and drop, concentration of salt in the sample solution, sodium tetrahydroborate (III) concentration in the drop and stirring rate. The method has been successfully validated against two fish certified reference materials (CRM 464 tuna fish and CRM DORM-2 dogfish muscle) following selective extraction of methylmercury in 2 mol/l HCl medium.

Gil, Sandra; Fragueiro, Sandra; Lavilla, Isela; Bendicho, Carlos

2005-01-01

138

Intercomparison of efficiency transfer software for gamma-ray spectrometry.  

PubMed

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. For carefully examining these results and trying to derive information for improving the computation codes, this study was limited to a few simple cases. The first part concerns the simplest case of geometry transfer, i.e., using point sources for 3 source-to-detector distances: 2, 5 and 20 cm; the second part deals with transfer from point source geometry to cylindrical geometry with three different matrices. The general conclusion is that the deviations between the computed results and the measured efficiencies are mostly within 10%. The quality of the results is rather inhomogeneous and shows that these codes cannot be used directly for metrological purposes. However, most of them are operational for routine measurements when efficiency uncertainties of 5-10% can be sufficient. PMID:11545502

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

2001-10-01

139

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

SciTech Connect

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 144Ce, 147Nd, 141Ce, 149Ba140La), 95 Zr(95Nb), 131mXe, 133mXe, 133gXe, 135gXe, and 37Ar. All of these nuclides (except 37Ar) can be measured via some form of conventional or coincidence-based gamma-ray spectrometry. The non-gaseous radionuclides [144Ce, 147Nd, 141Ce, 140Ba(140La), and 95Zr(95Nb)] can be measured via conventional high-resolution gamma-ray spectrometry using a shielded, high-purity germanium (HPGe) detector. The gaseous radionuclides 131mXe, 133mXe, 133gXe, and 135gXe are best measured (after separation from their homologous elements) via a gamma & beta/electron coincidence technique such as that described in CTBT/WGB/TL-11/5 which could utilize either a HPGe or low-resolution (NaI(TI)) gamma-ray spectrometer to detect the gamma-ray/x-ray and a plastic scintillator to detect the beta particle/electron from the decay of the various Xe isotopes. The US paper CTBT/PC/V/IOSI/WSII/PR/29 (and other papers) identified a need to limit the information that can be extracted from high-resolution gamma-ray spectra to ensure that only information relevant to an OSI is accessible. The term ?blinding? has been used to describe the need to limit the information available to the Inspection Team from the high-resolution gamma-ray measurement. A better term is ?measurement restriction?; the need for restricting the information is particularly relevant to conventional high-resolution gamma-ray spectrometry measurements, but not to the gamma & beta/electron coincidence-type measurements envisioned for Xe isotopes because the separation process for these radionuclides will likely eliminate any other observables. The purpose of this paper is to define functional requirements for restricting measurements via conventional high- resolution gamma-ray spectrometry systems to ensure that only the nuclides of interest to an OSI can be identified and quantified. Options discussed below include 1) acquisition and analysis of the entire high-resolution gamma-ray spectrum combined with a limited reporting mechanism, and 2) restricting of the gamma-ray spectrum prior to acquisition and analysis/reporting based upon only the limited portion of the spectrum. It is well recognized that the results should be as accurate as possible, but the analytical work must be performed in a manner consistent with the purposes of an OSI.

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

1998-11-06

140

Direct Exposure Probe/Mass Spectrometry and Pyrolysis-Gas Chromatography/Mass Spectrometry Study of the Effect of Gamma Radiation Exposure on the Thermal Degradation Products of Natural Rubber Polycaprolactone Mixtures.  

National Technical Information Service (NTIS)

This report describes the results of direct exposure probe-mass spectrometry and pyrolysis gas chromatography/mass spectrometry studies of the effect of gamma radiation exposure on the thermal degradation products of natural rubber, polycaprolactone, 70-3...

J. A. Hiltz T. Foster

1995-01-01

141

The influence of reactive side products on the electrooxidation of methanol - a combined in situ infrared spectroscopy and online mass spectrometry study.  

PubMed

Aiming at a better understanding of the impact of reaction intermediates and reactive side products on electrocatalytic reactions under conditions characteristic for technical applications, i.e., at high reactant conversions, we have investigated the electrooxidation of methanol on a Pt film electrode in mixtures containing defined concentrations of the reaction intermediates formaldehyde or formic acid. Employing simultaneous in situ infrared spectroscopy and online mass spectrometry in parallel to voltammetric measurements, we examined the effects of the latter molecules on the adlayer build-up and composition and on the formation of volatile reaction products CO2 and methylformate, as well as on the overall reaction rate. To assess the individual contributions of each component, we used isotope labeling techniques, where one of the two C1 components in the mixtures of methanol with either formaldehyde or formic acid was (13)C-labeled. The data reveal pronounced effects of the additional components formaldehyde and formic acid on the reaction, although their concentration was much lower (10%) than that of the main reactant methanol. Most important, the overall Faradaic current responses and the amounts of CO2 formed upon oxidation of the mixtures are always lower than the sums of the contributions from the individual components, indicative of a non-additive behavior of both Faradaic current and CO2 formation in the mixtures. Mechanistic reasons and consequences for reactions in a technical reactor, with high reactant conversion, are discussed. PMID:24866423

Reichert, R; Schnaidt, J; Jusys, Z; Behm, R J

2014-07-21

142

Apparatus for measuring the stopping power of active materials evaporated in situ and characterized by Auger electron spectrometry and Rutherford backscattering  

SciTech Connect

An ultrahigh-vacuum scattering chamber working in the low 10/sup -9/-mbar range is described. It is attached to a standard O-ring sealed beam transport system of an electrostatic accelerator. Twelve targets can be prepared in situ, one by one, by evaporating the material onto backings, which are mounted on tiltable target holders on a wheel. Backscattering spectra are obtained from these targets and the stopping cross section is deduced from their widths. A cooled high-resolution surface barrier detector is used for this purpose. The integral concentrations of light impurities in the target are obtained using Rutherford backscattering (RBS), whereas Auger electron spectrometry (AES) together with a sputtering device is used to determine the depth composition. As a test of the assembly we determined the stopping power of aluminum for protons and deuterons, respectively. The results are compared to published tables based upon fits to experiments. The influence of impurities on the result is discussed for an aluminum target prepared under standard evaporation conditions.

Semrad, D.; Bauer, P.; Eder, K.; Obermann, W.

1986-07-01

143

alpha-Particle and gamma-ray spectrometry of a plutonium solution for impurity determination.  

PubMed

A highly enriched (240)Pu solution was measured by alpha-particle and gamma-ray spectrometry to determine other radionuclides present in the material as impurities. Low activities of (238)Pu, (241)Am, (243)Cm and (244)Cm were determined by measuring thin sources, made from the original solution, in a high-resolution alpha-particle spectrometer. The sources were prepared by evaporating the plutonium solution on quartz plates in a vacuum chamber. From the ingrowth of (241)Am in the original solution, the amount of (241)Pu could be calculated. After radiochemical separation of (241)Am, the plutonium was measured by high-efficiency alpha-particle spectrometry to determine the amount of (238)Pu. The enriched (240)Pu material was also measured by high-resolution gamma-ray spectrometry, using two different HPGe detectors to determine the impurities of (239)Pu and (241)Am. The preparation of the sources and the measurement methods are described and discussed. The measured impurities, given in % of the (240)Pu activity, are compared with the values on the certificate. PMID:18356064

Sibbens, G; Altzitzoglou, T; Benedik, L; Pommé, S; Van Ammel, R

2008-01-01

144

In situ calibration of the Gamma Reaction History instrument using reference samples ("pucks") for areal density measurements  

NASA Astrophysics Data System (ADS)

The introduction of a sample of carbon, for example a disk or "puck", near an imploding DT-filled capsule creates a source of 12C gamma rays that can serve as a reference for calibrating the response of the Gamma Reaction History (GRH) detector [1]. Such calibration is important in the measurement of ablator areal density ??R?abl in plastic-ablator DT-filled capsules at OMEGA [2], by allowing ??R?abl to be inferred as a function of ratios of signals rather than from absolute measurements of signal magnitudes. Systematic uncertainties in signal measurements and detector responses therefore cancel, permitting more accurate measurements of ??R?abl.

Hoffman, N. M.; Herrmann, H. W.; Kim, Y. H.; Hsu, H. H.; Horsfield, C. J.; Rubery, M. S.; Wilson, D. C.; Stoeffl, W. W.; Young, C. S.; Mack, J. M.; Miller, E. K.; Grafil, E.; Evans, S. C.; Sedillo, T. J.; Glebov, V. Yu.; Duffy, T.

2013-11-01

145

A Case Study Correlating Innovative Gamma Ray Scanning Detection Systems Data to Surface Soil Gamma Spectrometry Results - 13580  

SciTech Connect

HydroGeoLogic (HGL), Inc. completed a United States Environmental Protection Agency (USEPA) study to characterize radiological contamination at a site near Canoga Park, California. The characterized area contained 470 acres including the site of a prototype commercial nuclear reactor and other nuclear design, testing, and support operations from the 1950's until 1988 [1]. The site history included radiological releases during operation followed by D and D activities. The characterization was conducted under an accelerated schedule and the results will support the project remediation. The project has a rigorous cleanup to background agenda and does not allow for comparison to risk-based guidelines. To target soil sample locations, multiple lines of evidence were evaluated including a gamma radiation survey, geophysical surveys, historical site assessment, aerial photographs, and former worker interviews. Due to the time since production and decay, the primary gamma emitting radionuclide remaining is cesium-137 (Cs-137). The gamma ray survey covered diverse, rugged terrain using custom designed sodium iodide thallium-activated (NaI(Tl)) scintillation detection systems. The survey goals included attaining 100% ground surface coverage and detecting gamma radiation as sensitively as possible. The effectiveness of innovative gamma ray detection systems was tested by correlating field Cs-137 static count ratios to Cs-137 laboratory gamma spectrometry results. As a case study, the area encompassing the former location of the first nuclear power station in the U. S. was scanned, and second by second global positioning system (GPS)-linked gamma spectral data were evaluated by examining total count rate and nuclide-specific regions of interest. To compensate for Compton scattering from higher energy naturally occurring radionuclides (U-238, Th-232 and their progeny, and K-40), count rate ratios of anthropogenic nuclide-specific regions of interest to the total count rate were calculated. From the scanning data, locations with observed Cs-137 ratios exceeding six standard deviations above the mean ratio were mapped in high resolution [2]. Field teams returned to those locations to collect static count measurements using the same detection systems. Soil surface samples were collected at 30 locations and analyzed for Cs-137. An exponential correlation was identified between Cs-137 concentrations in surface soil and field-scanned Cs-137 ratios. The data indicate field minimum detectable concentration (MDC) of Cs-137 at 0.02 Bq/g (0.5 pCi/g) or lower depending on contaminant distribution in soil. (authors)

Thompson, Shannon; Rodriguez, Rene; Billock, Paul [HydroGeoLogic, Inc., 11107 Sunset Hills Road, Suite 400, Reston, VA 20190 (United States)] [HydroGeoLogic, Inc., 11107 Sunset Hills Road, Suite 400, Reston, VA 20190 (United States); Lit, Peter [Nomad Science Group, 7738 Nautilus Shell Street, Las Vegas, NV 89139 (United States)] [Nomad Science Group, 7738 Nautilus Shell Street, Las Vegas, NV 89139 (United States)

2013-07-01

146

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

147

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

2010-07-01

148

Calibration of an air monitor prototype for a radiation surveillance network based on gamma spectrometry.  

PubMed

The objective of this work is to present the improvements that have been made in quasi-real-time air radioactivity concentration monitors which were initially based on overall activity determinations, by incorporating gamma spectrometry into the current prototype. To this end it was necessary to develop a careful efficiency calibration procedure for both the particulate and the gaseous fractions of the air being sampled. The work also reports the values of the minimum detectable activity calculated for different isotopes and acquisition times. PMID:24355305

Baeza, A; Caballero, J M; Corbacho, J Á; Ontalba-Salamanca, M Á; Vasco, J

2014-05-01

149

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

150

Nuclear chemistry of returned lunar samples: Nuclide analysis by gamma-ray spectrometry  

NASA Technical Reports Server (NTRS)

Primordial and cosmogenic radionuclide concentrations are determined nondestructively by gamma-ray spectrometry in soil and rock samples from the returned Apollo 17 sample collection from Taurus-Littrow and Descartes. Geochemical evidence in support of field geology speculation concerning layering of the subfloor basalt flows is demonstrated along with a possible correlation of magmatic fractionation of K/U as a function of depth. The pattern of radionuclide concentrations observed in these samples is distinct due to proton bombardment by the intense solar flares of August 4-9, 1972. Such radionuclide determinations are used in determining lunar sample orientation and characterizing solar flare activity.

Okelley, G. D.

1975-01-01

151

Precipitation correction of airborne gamma-ray spectrometry data using monitoring profiles: methodology and case study  

NASA Astrophysics Data System (ADS)

Variations of soil moisture content caused by precipitation often complicate the interpretation of airborne gamma-ray spectrometry data. This is particularly the case in repeated surveys designed to monitor the change of near surface abundances of radioactive elements or in large and time-consuming surveys. To counter this precipitation effect we propose a correction method based on repeated survey flights over a monitoring profile. Assuming that the weather and the soil conditions at the monitoring profile are representative for the survey area, the weather dependent effect of soil moisture can be observed and sufficiently corrected.

Ahl, Andreas; Motschka, Klaus; Slapansky, Peter

2014-08-01

152

Comparison of digital signal processing modules in gamma-ray spectrometry.  

PubMed

Commercial digital signal-processing modules have been tested for their applicability to gamma-ray spectrometry. The tests were based on the same n-type high purity germanium detector. The spectrum quality was studied in terms of energy resolution and peak area versus shaping parameters, using a Eu-152 point source. The stability of a reference peak count rate versus the total count rate was also examined. The reliability of the quantitative results is discussed for their use in measurement at the metrological level. PMID:24315086

Lépy, Marie-Christine; Cissé, Ousmane Ibrahima; Pierre, Sylvie

2014-05-01

153

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

NASA Astrophysics Data System (ADS)

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 from 24.72 to 78.48Bq·kg-1 for 226Ra, 21.73 to 75.28Bq·kg-1 for 232Th, 7.06 to 14.9Bq·kg-1 for 137Cs and 298.46 to 570.77Bq·kg-1 for 40K with the mean values of 42.11, 43.27, 9.5 and 418.27Bq·kg-1, respectively. The radium equivalent activity in all the soil samples is lower than the safe limit set in the OECD report (370Bq·kg-1). Man-made radionuclide 137Cs is also present in detectable amount in all soil samples. Presence of 137Cs indicates that the samples in this remote area also receive some fallout from nuclear accident in Chernobyl power plant in 1986. The internal and external hazard indices have the mean values of 0.48 and 0.37 respectively. Absorbed dose rates and effective dose equivalents are also determined for the samples. The concentration of radionuclides found in the soil samples during the present study is nominal and does not pose any potential health hazard to the general public.

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

2011-01-01

154

gamma. -ray spectrometry for determination of radium-228 and radium-226 in natural waters  

SciTech Connect

A technique has been developed for the measurement of /sup 228/Ra and /sup 226/Ra in both fresh- and seawater using Ge(Li) ..gamma..-ray spectrometry. Radium isotopes are preconcentrated in the field from 100 to 1000 L onto Mn-impregnated acrylic fiber cartridges, leached from the fiber and coprecipitated with BaSO/sub 4/. Lower limits of detection are controlled by the volume of water processed through the Mn fibers. In a 1-day count, samples as low as 10 dpm are measured to +-10% uncertainty. This Mn-fiber-..gamma..-ray technique is shown to be more accurate than the /sup 228/Ac methods recommended by the Environmental Protection Agency and as accurate but more rapid than the /sup 228/Th-Ingrowth procedure.

Michel, J.; Moore, W.S.; King, P.T.

1981-10-01

155

In situ composites  

SciTech Connect

The in situ formation of reinforcements, matrices, and interphases is a promising approach to decreasing the cost of high performance metal-ceramic composites. It develops high mechanical properties, and allows significant savings to be achieved by reducing or eliminating processing steps, reinforcing fibers, and reinforcement-matrix interfacial coatings. Several types of in situ composite materials are already being tested in real-world components, and others are expected to undergo such trials soon. Those closest to commercial application include in situ-toughened silicon nitride, in which high toughness comes from the development of high aspect-ratio grains during processing; some of the Lanxide materials, in which toughening phases (in the form of particles or metallic inclusions) are produced during processing; and the XD materials, notably {gamma}-TiAl intermetallics toughened by in situ-produced titanium diboride particulates, developed primarily by Martin Marietta. This article compares composites produced by in situ technologies with those produced by conventional means, and provides examples of several current and near-term applications of these materials.

Lewis, D. III [Naval Research Lab., Washington, DC (United States). Mechanics of Materials Branch; Singh, M. [NASA Lewis Research Center, Cleveland, OH (United States); Fishman, S.G. [Office of Naval Research, Arlington, VA (United States)

1995-07-01

156

Nondestructive measurement of neutron exposure in the BR-3 pressure vessel by continuous gamma-ray spectrometry  

SciTech Connect

Continuous gamma-ray spectrometry was used in the instrument tube of the BR-3 reactor water shield tank in an attempt to quantify the neutron exposure of the pressure vessel. A hybrid lead-natural uranium collimator-shield was used to surround the Si(Li) detectors of the Janus gamma-ray spectrometry probe. This hybrid collimator provided sufficient attenuation of the gamma field to reduce count rates to tolerable levels. Measurements were carried out at different elevations near midplane, from approximately 20 cm above to 10 cm below midplane. The dominant structure observed in these gamma-ray spectra was that of WCo, whereas the search for the VUMn gamma-ray (0.835 MeV) did not reveal any intensity above statistical fluctuations in the data. The absolute flux of WCo gamma-rays observed with the Janus probe is in good agreement with the calculated WCo flux. These calculations are based on the well-defined neutronic exposure of the BR-3 pressure vessel environment, which has been characterized on the basis of surveillance capsule dosimetry, dedicated thermal shield dosimetry sampling, and transport theory calculations. In light of this good agreement, the general applicability of continuous gamma-ray spectrometry for non-destructive neutron exposure measurements of light water reactor pressure vessels is discussed.

McNeece, J.P.; Gold, R.; Fabry, A.; DeLeeuw, S.; Gubel, P.

1984-07-01

157

Total Absorption Gamma-ray Spectrometer (TAGS) Intensity Distributions from INL's Gamma-Ray Spectrometry Center  

DOE Data Explorer

A 252Cf fission-product source and the INL on-line isotope separator were used to supply isotope-separated fission-product nuclides to a total absorption -ray spectrometer. This spectrometer consisted of a large (25.4-cm diameter x 30.5-cm long) NaI(Tl) detector with a 20.3-cm deep axial well in which is placed a 300-mm2 x 1.0-mm Si detector. The spectra from the NaI(Tl) detector are collected both in the singles mode and in coincidence with the B-events detected in the Si detector. Ideally, this detector would sum all the energy of the B- rays in each cascade following the population of daughter level by B- decay, so that the event could be directly associated with a particular daughter level. However, there are losses of energy from attenuation of the rays before they reach the detector, transmission of rays through the detector, escape of secondary photons from Compton scattering, escape of rays through the detector well, internal conversion, etc., and the measured spectra are thus more complicated than the ideal case and the analysis is more complex. Analysis methods have been developed to simulate all of these processes and thus provide a direct measure of the B- intensity distribution as a function of the excitation energy in the daughter nucleus. These data yield more accurate information on the B- distribution than conventional decay-scheme studies for complex decay schemes with large decay energies, because in the latter there are generally many unobserved and observed but unplaced rays. The TAGS data have been analyzed and published [R. E. Greenwood et al., Nucl Instr. and metho. A390(1997)] for 40 fission product-nuclides to determine the B- intensity distributions. [Copied from the TAGS page at http://www.inl.gov/gammaray/spectrometry/tags.shtml]. Those values are listed on this page for quick reference.

Greenwood, R.E.

158

First Year PIDDP Report on gamma-ray and x-ray spectroscopy: X-ray remote sensing and in situ spectroscopy for planetary exploration missions and gamma-ray remote sensing and in situ spectroscopy for planetary exploration missions  

NASA Technical Reports Server (NTRS)

Detectors that will be used for planetary missions must have their responses calibrated in a reproducible manner. In addition, it is important to characterize a detector system at uneven portions of its life cycle, for example after exposure to different amounts of radiation. A calibration and response characterization facility has been constructed at Schlumberger-Doll Research for all types of gamma- and x-ray detectors that may be used for planetary measurement. This facility is currently being tested. Initial use is expected for the MARS 94 detectors. The facility will then also be available for calibrating other detectors as well as arrays of detectors such as the NEAR detector with its central Nal(TI) crystal surrounded with a large BGO crystal. Cadmium telluride detectors are investigated for applications in space explorations. These detectors show an energy resolution of 5 keV for the 122 keV 57Co line. Earlier reported polarization effects are not observed. The detectors can be used at temperatures up to 100 C, although with reduced energy resolution. The thickness of standard detectors is limited to 2 mm. These detectors become fully efficient at bias voltages above 200 V. Initial results for a 1 cm thick detector show that the quality of the material is inferior to the thinner standard detectors and hole trapping affects the pulse height. A detailed characterization of the detector is in progress. Prototypes of photomultipliers based on a Channel Electron Multiplier (CEM) are being built to study their performance. Such photomultipliers promise better timing characteristics and a higher dynamic range while being more compact and of lower in weight.

Mahdavi, M.; Giboni, K. L.; Vajda, S.; Schweitzer, J. S.; Truax, J. A.

1994-01-01

159

The 124Sb activity standardization by gamma spectrometry for medical applications  

NASA Astrophysics Data System (ADS)

This work describes a metrological activity determination of 124Sb, which can be used as radiotracer, applying gamma spectrometry methods with hyper pure germanium detector and efficiency curves. This isotope with good activity and high radionuclidic purity is employed in the form of meglumine antimoniate (Glucantime) or sodium stibogluconate (Pentostam) to treat leishmaniasis. 124Sb is also applied in animal organ distribution studies to solve some questions in pharmacology. 124Sb decays by ?-emission and it produces several photons (X and gamma rays) with energy varying from 27 to 2700 keV. Efficiency curves to measure point 124Sb solid sources were obtained from a 166mHo standard that is a multi-gamma reference source. These curves depend on radiation energy, sample geometry, photon attenuation, dead time and sample-detector position. Results for activity determination of 124Sb samples using efficiency curves and a high purity coaxial germanium detector were consistent in different counting geometries. Also uncertainties of about 2% ( k=2) were obtained.

de Almeida, M. C. M.; Iwahara, A.; Delgado, J. U.; Poledna, R.; da Silva, R. L.

2010-07-01

160

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

161

Nondestructive characterization of radioactive waste drums by gamma spectrometry: a Monte Carlo technique for efficiency calibration.  

PubMed

A semi-empirical non-destructive technique to assay radioactive waste drums is presented. The technique is based on gamma spectrometry performed using a portable NaI detector and Monte Carlo simulations using the MCNP code in order to derive the gamma ray detector efficiency for the volume source. The derivation of detector efficiency was performed assuming homogeneous distribution of the source activity within the matrix material. Moreover, the MCNP model was used to examine the effect of inhomogeneities in activity distribution, variation of matrix material density, and drum filling height on the accuracy of the technique, and to estimate the measurement bias. The technique was verified by estimating radioactivity levels in 25 drums containing ion exchange resin waste, and comparing the results of the non-destructive method against the analytical results of samples obtained from each drum. Satisfactory agreement between the two assay techniques was observed. The discussed technique represents a cost effective technology that can be used to assay low-activity, low-density waste drums provided the contribution to the gamma ray spectrum can be resolved. PMID:18049246

Tzika, Faidra; Savidou, Anastasia; Stamatelatos, Ion E

2007-11-01

162

Cosmic veto gamma-spectrometry for Comprehensive Nuclear-Test-Ban Treaty samples  

NASA Astrophysics Data System (ADS)

The Comprehensive Nuclear-Test-Ban Treaty (CTBT) is supported by a global network of monitoring stations that perform high-resolution gamma-spectrometry on air filter samples for the identification of 85 radionuclides. At the UK CTBT Radionuclide Laboratory (GBL15), a novel cosmic veto gamma-spectrometer has been developed to improve the sensitivity of station measurements, providing a mean background reduction of 80.8% with mean MDA improvements of 45.6%. The CTBT laboratory requirement for a 140Ba MDA is achievable after 1.5 days counting compared to 5-7 days using conventional systems. The system consists of plastic scintillation plates that detect coincident cosmic-ray interactions within an HPGe gamma-spectrometer using the Canberra LynxTM multi-channel analyser. The detector is remotely configurable using a TCP/IP interface and requires no dedicated coincidence electronics. It would be especially useful in preventing false-positives at remote station locations (e.g. Halley, Antarctica) where sample transfer to certified laboratories is logistically difficult. The improved sensitivity has been demonstrated for a CTBT air filter sample collected after the Fukushima incident.

Burnett, J. L.; Davies, A. V.

2014-05-01

163

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

164

Recent achievements for In-situ measurement: applications to an actual decommissioning project  

SciTech Connect

Decommissioning a nuclear facility implies a policy of limiting the waste volume and its chemical - and especially radiological - toxicity. It is therefore important to determine the activity level contained in each component that will be dismantled. A variety of methods and analysis techniques are used for this purpose, ranging from simple dose rate measurements to {gamma} spectrometry and {gamma} imaging. The results of several measurement campaigns in a reactor currently in operation but for which decommissioning studies have now been undertaken are discussed. The measurements provide additional radiological data for the waste inventory, which is one of the first issues to be examined. This discussion focuses on the methods used ({gamma} imaging, in situ {gamma} spectrometry, etc.), the results obtained, and their implications for the project, as well as the technological and methodological innovations implemented during these campaigns. (authors)

Lamadie, F.; Girones, P.; Le Goaller, C.; Mahe, C. [CEA Marcoule, Dir. de l'Energie Nucleaire, Dept. de Declassement et de Conduite des Operations, 30 (France); Kohler, J.Y.; Risser, M.A. [CEA Marcoule, Dir. des Applications Militaires, Dept. Projet et Ingenierie des Installations, 30 (France)

2007-07-01

165

An iterative approach for TRIGA fuel burn-up determination using nondestructive gamma-ray spectrometry.  

PubMed

The purpose of this work is to establish a method for evaluating the burn-up values of the rod-type TRIGA spent fuel by using gamma-ray spectrometry of the short-lived fission products 97Zr/97Nb, 132I, and 140La. Fuel irradiation history is not needed in this method. Short-lived fission-product activities were established by reirradiating the spent fuels in a nuclear reactor. Based on the measured activities, 235U burn-up values can be deduced by iterative calculations. The complication caused by 239Pu production and fission is also discussed in detail. The burn-up values obtained by this method are in good agreement with those deduced from the conventional method based on long-lived fission products 137Cs, 134Cs/137Cs ratio and 106Ru/137Cs ratio. PMID:10670930

Wang, T K; Peir, J J

2000-01-01

166

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

167

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

168

Standardization of 222Rn by LSC and comparison with alpha- and gamma-spectrometry.  

PubMed

Liquid scintillation counting (LSC) was used for the measurement of 222Rn in equilibrium with its daughters, with detection efficiency close to 5. The appropriate corrections were considered, including one related to the probability that the 165-micros half-life 214Po decays during the dead time of the counter initiated by the disintegration of his parent nuclide, 214Bi. The dead-time determination of a commercial LS counter is also presented using a 222Rn standard source. The LSC 222Rn sources were prepared by transfer of 222Rn produced by a solid 226Ra source into LSC cocktail frozen at 77K, flame-sealed afterwards. They were measured using the LNHB triple coincidence counter with adjustable extending-type dead-time unit, between 8 and 100 micros; two different procedures were used to calculate an effective dead time and then to deduce the counting rate extrapolated to zero dead-time value. The LSC results were compared with those obtained by cryogenic alpha-particle spectrometry (LNHB system) and by gamma-ray spectrometry for the same radon source in the LSC vial; the geometry transfer coefficient was calculated using the ETNA software. Measurement results and uncertainties are discussed. PMID:16876423

Cassette, P; Sahagia, M; Grigorescu, L; Lépy, M C; Picolo, J L

2006-01-01

169

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

2000-01-01

170

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

171

Jarosite as a Storage Mineral for Small Organic Molecules: Investigations of Natural Samples Using an 'In Situ' Laser Desorption Fourier Transform Mass Spectrometry Technique  

NASA Astrophysics Data System (ADS)

The use of laser desorption Fourier transform mass spectrometry has revealed the presence of organic matter in several jarosite samples from various locations worldwide including jarosite precipitated in the lab by acidothiobacillus ferroxidans.

Kotler, J. M.; Hinman, N. W.; Yan, B.; Stoner, D. L.; Scott, J. R.

2007-03-01

172

Application of low-background gamma-ray spectrometry to monitor radioactivity in the environment and food.  

PubMed

The results are described of an upgrade of the low-background gamma-ray spectrometry laboratory at New York State Department of Health by acquiring sensitivity to low-energy gamma rays. Tuning of the spectrometer and its low-energy response characteristics are described. The spectrometer has been applied to monitor the environment by measuring aerosols and water in New York State contaminated by the 2011 Fukushima accident plume. In addition, the spectrometer has been used to monitor radioactivity in food by performing a study of cesium in Florida milk. PMID:24836905

Khan, A J; Semkow, T M; Beach, S E; Haines, D K; Bradt, C J; Bari, A; Syed, U-F; Torres, M; Marrantino, J; Kitto, M E; Menia, T; Fielman, E

2014-08-01

173

Gamma-ray spectrometry of radon in water and the role of radon to representatively sample aquifers.  

PubMed

Measurement of radon in water by gamma-ray spectrometry using a HPGe detector has been investigated to determine aquifer characteristics. The radon activity concentration is determined by taking the weighted average of the concentrations derived from gamma-ray lines associated with (214)Pb and (214)Bi decay. The role of accurate radon data to representatively sample aquifers was also investigated by studying a semi-cased borehole. A simplified physical model describing the change of radon concentration with the pumping time, reproduces the data and predicts the time for representative sampling of the aquifer. PMID:18515121

Talha, S A; Lindsay, R; Newman, R T; de Meijer, R J; Maleka, P P; Hlatshwayo, I N; Mlwilo, N A; Mohanty, A K

2008-11-01

174

Method of Evaluating Quantities of Plutonium by Gamma Spectrometry Applied to Measurement of Retention Monitoring of Wastes and Surveillance of Facility Dismantling.  

National Technical Information Service (NTIS)

The gamma spectrometry method of measuring quantities of plutonium has now been developed in different fields of nuclear work to enable reliable balance management to be carried out, to ensure safety requirements are met and to make better discharge monit...

J. Morel B. Chauvenet M. Etcheverry J. Monier Y. Labernede

1987-01-01

175

Implementation of gamma-ray spectrometry in two real-time water monitors using NaI(Tl) scintillation detectors.  

PubMed

In this study, the implementation of gamma-ray spectrometry in two real-time water monitors using 2 in. × 2 in. NaI(Tl) scintillation detectors is described. These monitors collect the water from the river through a pump and it is analyzed in a vessel, which is shielded with Pb. The full calibration of the monitors was performed experimentally, except for the efficiency curve, which was set using validated Monte Carlo simulations with the EGS5 code system. After the calibration, the monitors permitted the identification and quantification of the involved isotopes in a possible radioactive increment and made it possible to discard possible leaks in the nuclear plants. As an example, a radiological increment during rain is used to show the advantages of gamma-ray spectrometry. To study the capabilities of the monitor, the minimum detectable activity concentrations for (131)I, (137)Cs and (40)K are presented for different integration times. PMID:23827508

Casanovas, R; Morant, J J; Salvadó, M

2013-10-01

176

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

177

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

Microsoft Academic Search

Europium activated 6LiI crystal (enriched to 96% 6Li) has been studied in neutron and gamma-ray spectrometry. Two crystals of Oslash50 mm times 5 mm and Oslash30 mm times 3 mm size coupled to a calibrated Photonis XP5200 photomultiplier were tested. A response of 6LiI(Eu) to neutrons emitted from a paraffin moderated Pu-Be source has been investigated and the thermal neutron

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

2004-01-01

178

Using gamma ray spectrometry for fingerprinting sources of estuarine and coastal sediment in Mukawa coast, Hokkaido, northern Japan  

NASA Astrophysics Data System (ADS)

To seek the geological tracers of environmental radionuclide for fingerprinting sources of estuarine and coastal sediment, the gamma ray spectrometry was conducted for the soil and sediment samples collected from subcatchments, rivers, estuaries and coast in Mukawa and Sarugawa river watersheds and Mukawa coast, Hokkaido, northern Japan. Gamma ray spectrometry was conducted to determine the activities of environmental radionuclides associated with each soil and sediment samples using HP Ge well-type detector. Gamma ray spectrometry could determine 15 environmental radionuclides, including U-series, Th-series, cesium-137 and potassium-40. Lead-210 excess was also determined by subtracting the activities of Pb-214 from that of Pb-210. The Kruskal-Wallis H test was conducted to assess the ability of each tracer property to discriminate between surface soil samples from the categories divided by subcatchment, geological era and period, suggesting that more than 11 tracer properties were available. Subsequently, the stepwise discriminant function analysis was conducted to identify which combination of tracer properties provides the best composite fingerprint for differentiating source materials on the basis of subcatchment and geology source groups. This analysis suggested that the composite fingerprints of Pb-212, Ac-228 and K-40 can classify the geology into 6 groups based on rock type. Using these tracer properties, the contribution of rock to estuarine and coastal sediment can be evaluated with the multivariate sediment mixing model.

Mizugaki, S.; Ohtsuka, J.; Murakami, Y.; Ishiya, T.; Hamamoto, S.

2010-12-01

179

Assessment of radiological hazards of Lawrencepur sand, Pakistan using gamma spectrometry.  

PubMed

The Lawrencepur sand had remained refrigerated during a long period of glaciations in the study area. Owing to its derivation from the granitic rocks of the Himalayas and its preservation under glacial environment, the sand grains are still fresh and may contain high level of primordial radioactivity. For that reason, radiological hazards of Lawrencepur sand were assessed using a high-purity germanium gamma spectrometry technique. The average activity concentrations of (226)Ra, (232)Th and (40)K were found to be 15.97±3.05, 27.98±4.89 and 498.20±15.91 Bq kg(-1), respectively. These values are higher than those of the sands of many countries of the world but lower than those of some of the Pakistani, Indian and Egyptian sands. The outdoor and indoor hazard indices and annual effective doses of the Lawrencepur sand are higher than those of some of the sand deposits of European, African and American countries but lower than those of nearby Pakistani and Indian sands. However, the hazard indices and annual effective doses of the Lawrencepur sand are within the safe limits. Overall, the Lawrencepur sand does not pose any radiological health hazard as a building material. PMID:23630384

Qureshi, Aziz Ahmed; Ali, Muhammad; Waheed, Abdul; Manzoor, Shahid; Siddique, Rehan Ul Haq; Ahmed Khan, Hameed

2013-11-01

180

Low-background gamma-ray spectrometry in the Garching underground laboratory  

NASA Astrophysics Data System (ADS)

We describe two setups that were built for low-background gamma-ray spectrometry in the Garching Underground Laboratory (~ 10 m.w.e.). Both setups are based on HPGe detectors surrounded by several layers of passive shielding as well as an active muon veto. The first setup (GEM) comprises a single HPGe detector surrounded by a NaI(Tl) scintillation detector that serves as anti-Compton veto. The second setup (LoAx) consists of two smaller HPGe detectors which are arranged face-to-face to cover a large solid angle around the sample. The detection efficiency of both systems is determined using a calibrated Monte-Carlo simulation. The count rate finally achieved in the energy range 40-2700keV is 10250+/-26cts/day for the GEM setup, and 5258+/-27cts/day and 6876+/-31cts/day between 20-1500keV for the two detectors of the LoAx setup. This leads to detection sensitivities of a few mBq/kg for U and Th at both screening stations.

Hofmann, M.; Mannel, T.; Sivers, M. V.

2013-08-01

181

Detection of /sup 210/Pb in the lungs of smokers by in-vivo gamma spectrometry  

SciTech Connect

Since mainstream smoke is highly enriched in /sup 210/Pb, alpha radiation from inhaled cigarette smoke particles has been proposed as a cancer-producing agent in cigarette smokers. /sup 210/Po and /sup 210/Pb have been observed in tobacco, cigarette smoke and in the lungs of smokers. Since /sup 210/Pb is highly enriched in mainstream smoke, there have been estimates of yearly excesses of /sup 210/Pb in the lungs of one-pack-a-day smokers of 3 to 10 pCi (0.11 to 0.37 Bq). The ORNL Whole Body Counter was used to verify this estimate by the methodology of high-resolution, in vivo gamma spectrometry. Measurements were made on 113 adult male non-radiation workers who have either smoked at least one pack of cigarettes per day for at least five years, or have never smoked cigarettes. An analysis-of-variance table was generated based on the Pb-ratio for each individual which revealed that there was no statistically significant increase in the amount of /sup 210/Pb in the lungs of smokers over those of non-smokers. Sources of error are also discussed.

Berger, C.D.; Lane, B.H.

1982-09-01

182

Vergleichsmessungen der Bodenkontamination mit Hilfe der In-situ-Spectrometrie. T. 2. Natuerliche Radionuclide. (Intercomparison measurements of surface soil contamination with in-situ gamma ray spectrometry. Pt.2. Natural radionuclides).  

National Technical Information Service (NTIS)

The intercomparison program was performed by the Federal Office of Radiation Protection in October 1993. 17 teams - 10 from Germany and 7 from other european countries - took part in the measurements. Three characteristic sites at the Ronneburg (Wismut Lt...

I. Winkelmann

1994-01-01

183

Gamma-spectrometric measurements of natural-radionuclide contents in soil and gamma dose rates in Yangjiang, PR China  

NASA Astrophysics Data System (ADS)

The average concentration of natural radionuclides in a high-radiation-background area and a control area in Yangjiang and the Enping county of the province Guangdong, PR China, have been measured by in-situ gamma spectrometry and by sampling analysis in our laboratory. Average data on surface and depth distributions in soil have been obtained. The exposure rates to the environmental gamma-radiation field in both areas have been calculated from in-situ gamma spectra with Beck's conversion factor and by the method of total spectrum energy. The averaged total absorbed dose rates, including the cosmic-ray contribution obtained from in-situ gamma spectroscopy, are (18.2 ± 5.0) × 10 -8 and (6.6 ± 1.2) × 10 -8 Gy/h in the high-background and control areas, respectively.

Daling, Luo; Chunxiang, Zhang; Zujie, Guan; Xian, Lai; Guorong, Huang

1990-12-01

184

Determination of Hafnium in Zirconium Standard Samples (JAERI-Z15,-Z16) by Neutron Activation and gamma-Ray Spectrometry of Sup(179M)Hf.  

National Technical Information Service (NTIS)

Trace amounts of hafnium in zirconium standard samples (JAERI-Z15,-Z16) were determined by neutron activation and gamma-ray spectrometry where 214.3 keV gamma-ray emitted from sup(179m)Hf (T sub(1/2) = 18.6 sec) are counted by a Ge(Li) detector. The zirco...

C. Yonezawa K. Takashima

1979-01-01

185

In situ analysis of plant tissue underivatized carbohydrates and on-probe enzymatic degraded starch by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry by using carbon nanotubes as matrix.  

PubMed

Underivatized carbohydrates of tulip bulb and leaf tissues were characterized in situ by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) by using carbon nanotubes (CNTs) as matrix. Two sample preparation methods--(i) depositing CNTs on the fresh tissue slices placed on the probe and (ii) locating semitransparent tissues on a dried layer of CNTs on the probe--were examined. Furthermore, practicability of in situ starch analysis by MALDI-TOF MS was examined by detection of glucose originated from on-probe amyloglucosidase-catalyzed degradation of starch on the tissue surface. Besides, CNTs could efficiently desorb/ionize natural mono-, di-, and oligosaccharides extracted from tulip bulb tissues as well as glucose resulting from starch enzymatic degradation in vitro. These results were compared with those obtained by in situ MALDI-TOF MS analysis of similar tissues. Positive ion mode showed superior signal reproducibility. CNTs deposited under semitransparent tissue could also desorb/ionize neutral carbohydrates, leading to nearly complete elimination of matrix cluster signals but with an increase in tissue-originated signals. Furthermore, several experiments were carried out to compare the efficiency of 2,5-dihydroxybenzoic acid, nor-harmane, alpha-cyano-4-hydroxycinnamic acid, and CNTs as matrices for MALDI of neutral carbohydrates from the intact plant tissue surface and for enzymatic tissue starch degradation; these results are discussed in brief. Among matrices studied, the lowest laser power was needed to acquire carbohydrate signals with high signal-to-noise ratio and resolution when CNTs were used. PMID:18805390

Gholipour, Yousef; Nonami, Hiroshi; Erra-Balsells, Rosa

2008-12-15

186

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

2008-10-01

187

In-situ probing of the biotic-abiotic boundary of plants by laser desorption\\/ionization time-of-flight mass spectrometry  

Microsoft Academic Search

Laser desorption\\/ionization time-of-flight (LDI-TOF) mass spectrometry was applied for the direct analysis of cuticular waxes\\u000a on intact plant tissues. Cuticular wax compounds were ionized by laser desorption in the presence of colloidal silver. Silver-adduct\\u000a ions were detected on samples from Arabidopsis thaliana and from maize. Good spot-to-spot reproducibility indicated homogeneous coverage of the sample by the fine colloidal material.\\u000a The

Chanan Sluszny; Edward S. Yeung; Basil J. Nikolau

2005-01-01

188

Mechanistic aspects of the water–gas shift reaction on alumina-supported noble metal catalysts: In situ DRIFTS and SSITKA-mass spectrometry studies  

Microsoft Academic Search

Steady-state isotopic transient kinetic analysis (SSITKA) experiments coupled with mass spectrometry were performed for the first time to study essential mechanistic aspects of the water–gas shift (WGS) reaction over alumina-supported Pt, Pd, and Rh catalysts. In particular, the concentrations (?molg?1) of active intermediate species found in the carbon-path from CO to the CO2 product gas (use of 13CO), and in

George G. Olympiou; Christos M. Kalamaras; Constantinos D. Zeinalipour-Yazdi; Angelos M. Efstathiou

2007-01-01

189

Identification of natural dyes used in works of art by pyrolysis–gas chromatography\\/mass spectrometry combined with in situ trimethylsilylation  

Microsoft Academic Search

Samples of four natural dyes from different organic families—natural madder (anthraquinonoid), curcuma (curcuminoid), saffron (carotenoid) and indigo (indigotic)—were analysed using a new procedure based on pyrolysis–gas chromatography\\/mass spectrometry (Py–GC\\/MS), which includes the on-line derivatisation of the natural dyes using hexamethyldisilazane (HMDS). In addition, a previous procedure involving the addition of a 10% H2SO4 aqueous solution to the dye and further

María José Casas-Catalán; María Teresa Doménech-Carbó

2005-01-01

190

The determination of total Se in urine and serum by graphite furnace atomic absorption spectrometry using Ir as permanent modifier and in situ oxidation for complete trimethylselenonium recovery  

Microsoft Academic Search

The present work evaluated the use of iridium (Ir) as permanent modifier for the determination of total selenium in urine\\u000a and serum by graphite furnace atomic absorption spectrometry. Concerning urine, the presence of trimethylselenonium (TMSe+) was especially considered. Pyrolysis and atomization temperatures of 1,000 and 2,100°C, respectively, were used. For nondigested\\u000a urine and serum samples, 0.2% v\\/v HNO3 and Triton

Patricia Grinberg; Rodrigo Araújo Gonçalves; Reinaldo Calixto de Campos

2005-01-01

191

Direct determination of silicon in powdered aluminium oxide by use of slurry sampling with in situ fusion graphite-furnace atomic-absorption spectrometry  

Microsoft Academic Search

A direct method for determination of silicon in powdered high-purity aluminium oxide samples, by slurry sampling with in\\u000a situ fusion graphite-furnace atomic-absorption spectrometry (GF-AAS), has been established. A slurry sample was prepared\\u000a by 10-min ultrasonication of a powdered sample in an aqueous solution containing both sodium carbonate and boric acid as a\\u000a mixed flux. An appropriate portion of the slurry

H. Minami; Tomomi Yoshida; Kentaro Okutsu; Qiangbin Zhang; Sadanobu Inoue; Ikuo Atsuya

2001-01-01

192

Detection of in vitro kinase generated protein phosphorylation sites using gamma[18O4]-ATP and mass spectrometry.  

PubMed

A novel stable-isotope labeling approach for identification of phosphopeptides that utilizes adenosine triphosphate, in which four oxygen-16 atoms attached to the terminal phosphate group are substituted with oxygen-18 [gamma((18)O4)-ATP], has been developed. The ability to use gamma((18)O4)-ATP to monitor phosphorylation modification within various proteins was conducted by performing in vitro kinase reactions in the presence of a 1:1 mixture of gamma((18)O4)-ATP and normal isotopic abundance ATP (ATP). After tryptic digestion, the peptides were analyzed using mass spectrometry (MS). Phosphorylated peptides are easily recognized within the MS spectrum owing to the presence of doublets separated by 6.01 Da; representing versions of the peptide modified by ATP and gamma((18)O4)-ATP. Standard peptides phosphorylated using gamma((18)O4)-ATP via in vitro kinase reactions showed no exchange loss of (18)O with (16)O. The identity of these doublets as phosphorylated peptides could be readily confirmed using tandem MS. The method described here provides the first direct stable-isotope labeling method to definitely detect phosphorylation sites within proteins. PMID:17877366

Zhou, Ming; Meng, Zhaojing; Jobson, Andrew G; Pommier, Yves; Veenstra, Timothy D

2007-10-15

193

A new variant of the gamma subunit of renal Na,K-ATPase. Identification by mass spectrometry, antibody binding, and expression in cultured cells.  

PubMed

The gamma subunit is a specific regulator of Na,K-ATPase expressed mainly in kidney. On SDS-polyacryylamide gel electrophoresis, gamma runs as a doublet, but the origin and significance of the doublet is obscure. Mass spectrometry of the gamma chains of rat kidney Na, K-ATPase shows that gamma(a) (upper) has a mass of 7184.0 +/- 1 Da (carbamidomethyl cysteine), corresponding closely to that for the published sequence without the initiator methionine, while gamma(b) (lower) has a mass of 7337.9 +/- 1Da. Tryptic peptide mapping and sequencing by mass spectrometry reveals that the seven N-terminal residues of gamma(a), TELSANH, are replaced by Ac-MDRWYL in gamma(b), but otherwise the chains are identical. Antibodies raised against peptides TELSANHC and MDRWYLC recognize either gamma(a) or gamma(b) of the Na,K-ATPase, respectively. gamma(a) or gamma(b) cDNAs have been expressed in human embryonic kidney and HeLa cells. The major bands expressed correspond to gamma(a) or gamma(b) of renal Na, K-ATPase. Additional minor bands seen after transfection, namely gamma(a)' in human embryonic kidney and gamma(b)' in HeLa, are presumably cell-specific modifications. The present work clarifies earlier uncertainty regarding doublets seen in kidney and in transfected cells. In particular, the results show that renal Na, K-ATPase contains two variants of the gamma subunit with different sequences but otherwise are unmodified. We discuss the possible functional significance of the two variants. PMID:10748024

Kuster, B; Shainskaya, A; Pu, H X; Goldshleger, R; Blostein, R; Mann, M; Karlish, S J

2000-06-16

194

Methylation of gamma-carboxylated Glu (Gla) allows detection by liquid chromatography-mass spectrometry and the identification of Gla residues in the gamma-glutamyl carboxylase  

PubMed Central

Gamma-carboxylated Glu (Gla) is a post-translational modification required for the activity of vitamin K-dependent (VKD) proteins that has been difficult to study by mass spectrometry due to the properties of this negatively-charged residue. Gla is generated by a single enzyme, the gamma-glutamyl carboxylase, which has broad biological impact because VKD proteins have diverse functions that include hemostasis, apoptosis, and growth control. The carboxylase also contains Glas, of unknown function, and is an integral membrane protein with poor sequence coverage. To locate these Glas, we first established methods that resulted in high coverage (92%) of uncarboxylated carboxylase. Subsequent analysis of carboxylated carboxylase identified a Gla-peptide (729-758) and a missing region (625-647) that was detected in uncarboxylated carboxylase. We therefore developed an approach to methylate Gla, which efficiently neutralized Gla and improved mass spectrometric analysis. Methylation eliminated CO2 loss from Gla, increased the ionization of Gla-containing peptide, and appeared to facilitate trypsin digestion. Methylation of a carboxylated carboxylase tryptic digest identified Glas in the 625-647 peptide. These studies provide valuable information for testing the function of carboxylase carboxylation. The methylation approach for studying Gla by mass spectrometry is an important advance that will be broadly applicable to analyzing other VKD proteins.

Hallgren, K. W.; Zhang, D.; Kinter, M.; Willard, B.; Berkner, K. L.

2013-01-01

195

Headspace single-drop microextraction with in situ stibine generation for the determination of antimony (III) and total antimony by electrothermal-atomic absorption spectrometry  

Microsoft Academic Search

A headspace-single drop microextraction method combined with electrothermal atomic absorption spectrometry (ETAAS) is developed\\u000a for the extraction and preconcentration of antimony(III) and total antimony into a Pd(II)-containing aqueous drop after hydride\\u000a generation. Experimental variables such as hydrochloric acid and sodium tetrahydroborate concentrations, sample volume, Pd(II)\\u000a concentration in the acceptor phase and microextraction time were optimized. A 26-2\\u000a IV factorial fractional

Francisco Pena-Pereira; Isela Lavilla; Carlos Bendicho

2009-01-01

196

Determination of the natural radioactivity in Qatarian building materials using high-resolution gamma-ray spectrometry  

NASA Astrophysics Data System (ADS)

This study is aimed at the determination of the activity concentrations of naturally occurring and technically enhanced levels of radiation in building materials used across the State of Qatar. Samples from a range of common building materials, including Qatarian cement, Saudi cement, white cement, sand and washed sand, have been analyzed, in addition to other samples of cement's raw materials and additives collected from the main suppliers in Qatar. In order to establish the activity concentrations associated with the 235,8U and 232Th natural decay chains and 40K, the samples have been studied using a high-resolution, low-background gamma-ray spectrometry set-up. Details of the sample preparation and the gamma-ray spectroscopic analysis techniques are presented, together with the preliminary results of the activity concentrations associated with the naturally occurring radionuclide chains for the building materials collected across the Qatarian peninsula.

Al-Sulaiti, Huda; Alkhomashi, N.; Al-Dahan, N.; Al-Dosari, M.; Bradley, D. A.; Bukhari, S.; Matthews, M.; Regan, P. H.; Santawamaitre, T.

2011-10-01

197

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

198

A portable gas chromatograph with simultaneous detection by mass spectrometry and electroantennography for the highly sensitive in situ measurement of volatiles.  

PubMed

Mating disruption is a sustainable method for the control of insect pests, involving the release of synthetic sex pheromones that disrupt the olfactory localization of females by males. However, the development and refinement of this strategy is hampered because current instruments lack the sensitivity to detect volatile organic chemicals in the field, and portable electroantennograms produce non-comparable relative units and distorted results in the presence of plant volatiles. To address the demand for more sensitive instruments that are suitable for the rapid in situ detection of airborne pheromones, we have developed a portable, automated needle trap device connected to a gas chromatograph, mass spectrometer, and electroantennographic detector (NTD-GC-MS/EAD) suitable for field applications. We tested the instrument by measuring the concentration of the sex pheromone (E,Z)-7,9-dodecadienyl acetate, which is used to disrupt the mating of the European grapevine moth Lobesia botrana (Lepidoptera: Tortricidae). Our data confirm that the instrument generates highly reproducible results and is highly sensitive, with a detection threshold of 3 ng/m(3) (E,Z)-7,9-dodecadienyl acetate in outside air. PMID:23954942

Schott, Matthias; Wehrenfennig, Christoph; Gasch, Tina; Düring, Rolf-Alexander; Vilcinskas, Andreas

2013-09-01

199

Mercury speciation and analysis in drinking water by stir bar sorptive extraction with in situ propyl derivatization and thermal desorption-gas chromatography-mass spectrometry.  

PubMed

A method for mercury analysis and speciation in drinking water was developed, which involved stir bar sorptive extraction (SBSE) with in situ propyl derivatization and thermal desorption (TD)-GC-MS. Ten millilitre of tap water or bottled water was used. After a stir bar, pH adjustment agent and derivatization reagent were added, SBSE was performed. Then, the stir bar was subjected to TD-GC-MS. The detection limits were 0.01 ng mL(-1) (ethylmercury; EtHg), 0.02 ng mL(-1) (methylmercury; MeHg), and 0.2 ng mL(-1) (Hg(II) and diethylmercury (DiEtHg)). The method showed good linearity and correlation coefficients. The average recoveries of mercury species (n=5) in water samples spiked with 0.5, 2.0, and 6.0 ng mL(-1) mercury species were 93.1-131.1% (RSD<11.5%), 90.1-106.4% (RSD<7.8%), and 94.2-109.6% (RSD<8.8%), respectively. The method enables the precise determination of standards and can be applied to the determination of mercury species in water samples. PMID:18823893

Ito, Rie; Kawaguchi, Migaku; Sakui, Norihiro; Honda, Hidehiro; Okanouchi, Noriya; Saito, Koichi; Nakazawa, Hiroyuki

2008-10-31

200

Etude des desequilibres radioactifs dans les familles de l'uranium par la spectrometrie gamma a basse energie et application a la datation en geologie. (Uranium series radioactive disequilibria study using gamma spectrometry with low energy and application to the dating in geology).  

National Technical Information Service (NTIS)

In this work, the gamma spectrometry with low energy has been used with the help of Ge high purity planar detector, and the means and limits of this spectrometry in the applications to the dating in geology has been studied. A geological sample taken from...

T. Khoukhi

1992-01-01

201

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

202

Quantitative analysis of gamma-hydroxybutyrate at endogenous concentrations in hair using liquid chromatography tandem mass spectrometry.  

PubMed

A method capable of quantifying endogenous concentrations of gamma-hydroxybutyrate (GHB) in human head hair was developed and validated using liquid chromatography/mass spectrometry/mass spectrometry (LC/MS/MS). Hair was digested under alkaline conditions, and GHB was isolated using liquid-liquid extraction. LC/MS/MS was performed using atmospheric pressure chemical ionization in the negative mode, multiple reaction monitoring, and deuterated internal standard (GHB-D(6)). Linearity was observed between 0.1 and 100 ng/mg GHB (R(2) = 1.000). The limits of detection and quantitation in human hair were 0.2 and 0.4 ng/mg, respectively. Accuracy at 2 ng/mg and 10 ng/mg was determined to be 97% and 94%, and intra-assay CVs at these concentrations were 5.2% and 7.4% (n = 4). Beta-hydroxybutyrate (BHB), alpha-hydroxybutyrate, gamma-butyrolactone, and 1,4-butanediol did not produce an interference, and there was negligible ion suppression or enhancement from the matrix. PMID:20141559

Stout, Phillip A; Simons, Kelsie D; Kerrigan, Sarah

2010-03-01

203

Self-absorption correction factor applied to 129I measurement by direct gamma-X spectrometry for Fucus serratus samples  

NASA Astrophysics Data System (ADS)

Self-absorption corrections have been determined for the energies characterising 129I below 40 keV in the frame of studying Fucus serratus samples by direct gamma-X spectrometry. This work was performed on a large spatio-temporal scale in order to integrate the fluctuations of the matrix. More than 200 samples monthly collected from January 1983 to December 1996 along the French Atlantic and English Channel coasts, have been measured as part of the Permanent Observatory of the radioactivity programme of the Institut de Radioprotection et de Sûreté Nucléaire (IRSN). A relationship has been established between experimental mass attenuation coefficients at low energy and the 40K concentrations of the samples, where the latter showed the same temporal variation as the 127I concentration (iodine stable isotope). Based on the mean correction factors determined in the present work, a simplified method is proposed to quantify the content of 129I. The direct gamma-X spectrometry results obtained in this way are in good agreement with those reported by Patti et al. (Radioprotection 23 (1988) 381) using neutron activation analysis for the samples collected between October 1983 and December 1984 at Herquemoulin, located near the La Hague reprocessing plant.

Lefèvre, O.; Bouisset, P.; Germain, P.; Barker, E.; Kerlau, G.; Cagnat, X.

2003-06-01

204

Evidence of enhanced mobility at the free surface of supported polymer films by in situ variable-temperature time-of-flight-secondary ion mass spectrometry.  

PubMed

Time-of-flight secondary ion mass spectrometry (TOF-SIMS) spectra of polystyrene (PS) films supported on silicon wafers were obtained at temperatures ranging from room temperature to 100 °C. Principal component analysis (PCA) of the TOF-SIMS data revealed a transition temperature (TT) at which the surface structure of PS was rearranged. The TT of a 120-nm thick PS (weight-average molecular weight of 3,000 g/mol) thin film was determined to be about 36 °C, which is approximately 30 °C lower than the bulk glass transition temperature (Tg) of that PS. Similar TTs were observed on PSs with different molecular weights. As the TT is strongly related to the Tg and dependent on the molecular weight, it is believed that the TT determined by TOF-SIMS is related to the surface glass transition temperature (Tg(S)) measured by other techniques. This suggests that TOF-SIMS combined with PCA can be used to determine the Tg(S) of polymer films. Furthermore, the detailed PCA analyses indicate that the phenyl groups of PS tended to move away from the surface at temperatures above TT. This conclusion was further confirmed by contact angle and XPS measurements. PMID:24106990

Fu, Yi; Lau, Yiu-Ting R; Weng, Lu-Tao; Ng, Kai-Mo; Chan, Chi-Ming

2013-11-19

205

Optimization of a single-drop microextraction method for multielemental determination by electrothermal vaporization inductively coupled plasma mass spectrometry following in situ vapor generation  

NASA Astrophysics Data System (ADS)

A headspace single-drop microextraction (HS-SDME) method has been developed in combination with electrothermal vaporization inductively coupled plasma mass spectrometry (ETV-ICP-MS) for the simultaneous determination of As, Sb, Bi, Pb, Sn and Hg in aqueous solutions. Vapor generation is carried out in a 40 mL volume closed-vial containing a solution with the target analytes in hydrochloric acid and potassium ferricyanide medium. Hydrides (As, Sb, Bi, Pb, Sn) and Hg vapor are trapped onto an aqueous single drop (3 µL volume) containing Pd(II), followed by the subsequent injection in the ETV. Experimental variables such as medium composition, sodium tetrahydroborate (III) volume and concentration, stirring rate, extraction time, sample volume, ascorbic acid concentration and palladium amount in the drop were fully optimized. The limits of detection (LOD) (3 ? criterion) of the proposed method for As, Sb, Bi, Pb, Sn and Hg were 0.2, 0.04, 0.01, 0.07, 0.09 and 0.8 µg/L, respectively. Enrichment factors of 9, 85, 138, 130, 37 and 72 for As, Sb, Bi, Pb, Sn and Hg, respectively, were achieved in 210 s. The relative standard deviations ( N = 5) ranged from 4 to 8%. The proposed HS-SDME-ETV-ICP-MS method has been applied for the determination of As, Sb, Bi, Pb, Sn and Hg in NWRI TM-28.3 certified reference material.

Gil, Sandra; de Loos-Vollebregt, Margaretha T. C.; Bendicho, Carlos

2009-03-01

206

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

207

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

2013-06-12

208

Three Independent Techniques Localize Expression of Transcript afp-11 and Its Bioactive Peptide Products to the Paired AVK Neurons in Ascaris suum: In Situ Hybridization, Immunocytochemistry, and Single Cell Mass Spectrometry  

PubMed Central

We utilized three independent techniques, immunocytochemistry (ICC), single cell mass spectrometry (MS), and in situ hybridization (ISH), to localize neuropeptides and their transcripts in the nervous system of the nematode Ascaris suum. AF11 (SDIGISEPNFLRFa) is an endogenous peptide with potent paralytic effects on A. suum locomotory behavior. A highly specific antibody to AF11 showed robust immunostaining for AF11 in the paired AVK neurons in the ventral ganglion. We traced the processes from the AVK neurons into the ventral nerve cord and identified them as ventral cord interneurons. MS and MS/MS of single dissected AVKs detected AF11, two previously characterized peptides (AF25 and AF26), seven novel sequence-related peptides, including several sharing a PNFLRFamide C-terminus, and peptide NY, a peptide with an unrelated sequence. Also present in a subset of AVKs was AF2, a peptide encoded by the afp-4 transcript. By sequencing the afp-11 transcript, we discovered that it encodes AF11, all the AF11-related peptides detected by MS in AVK, and peptide NY. ISH detected the afp-11 transcript in AVK neurons, consistent with other techniques. ISH did not detect afp-11 in the ALA neuron, although both ICC and MS found AF11 in ca. 30% of ALAs. All 10 AF11-related peptides reduced acetylcholine-induced muscle contraction, but they differed in their rate of reversal of inhibition after removal of the peptide.

2012-01-01

209

Online in situ analysis of selected semi-volatile organic compounds in water by automated microscale solid-phase extraction with large-volume injection/gas chromatography/mass spectrometry.  

PubMed

A fully automated analytical method was developed for the online in situ analysis of selected semi-volatile organic compounds in water. The method used a large-volume injection/gas chromatography/mass spectrometry coupled with a fully automated microscale solid-phase extraction technique, which was based on x-y-z robotic techniques. Water samples were extracted by using a 96-well solid-phase extraction plate. For most analytes included in this study, the obtained linear calibrations ranged from 0.05 to 5.0 microg/L with correlation coefficients of 0.996-1.000, the method detection limits were less than 0.1 microg/L, and the relative recoveries were in the range of 70-120% with a relative standard deviation of less than 15% for fortified reagent water samples. The applications to chlorinated tap water, well water, and river water have been validated. The obtained results were similar to those resulting from fortified reagent water samples for all analytes except metribuzin, bromacil, aldrin, and methoxychlor. Matrix effects were observed for these analytes. In general, this fully automated analytical method was rugged, reliable, and easy to operate, and was capable of providing real-time data to water treatment and distribution systems as well as water reservation and protection systems. In addition, the method could reduce the analytical costs associated with sample collection, transportation, storage, and preparation. PMID:18036538

Li, Yongtao; George, John E; McCarty, Christina L

2007-12-28

210

A nondestructive method based on gamma spectrometry for the measurements of plutonium hold-up or plutonium wastes  

SciTech Connect

With respect to in-plant holdup and wastes, plutonium quantities are measured in most cases by nondestructive methods such as neutron counting, gamma-photon counting, and infrared detection. These methods are often imperfect for various reasons: difficult access to sample, highly radioactive background, screens, etc. It is therefore of interest to develop other methods in order to check the results from these techniques or improve them. The quick method described is used for measuring the quantities of plutonium kept in various types of containers such as gloveboxes, cans, etc. It is applicable to the evaluation of sample masses ranging from a few tens of milligrams to several tens of grams. It is based on the gamma-ray spectrometry technique with germanium detectors. Gamma rays emitted by plutonium isotopes in the 100- to 500-keV energy range permit us, after a quick isotope composition determination, to obtain the plutonium total mass corrected for absorption and self-absorption by extrapolation to infinite energy of the apparent masses calculated for the energies of the selected peaks. This method has been used for several months in different fields such as the accountancy of the plutonium holdup in fuel fabrication plants; the reprocessing and the storage of radioactive wastes; and the supervision of the dismantlement.

Morel, J.; Chauvenet, B.; Etcheverry, M.; Louppe, L.; Monier, J.

1987-01-01

211

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

212

Direct determination of 226 Ra in NORM\\/TENORM matrices by gamma-spectrometry  

Microsoft Academic Search

Summary  The main shortcoming with the procedure to determine 226Ra in a gamma spectrum of an environmental sample by means of the 214Bi and 214Pb photopeaks is the likelihood of 222Rn leakage from the sample counting vial. An option to make such determination is to disregard the 226Ra gamma-contributions to the spectrum, other than 186.2 keV (3.5%), subtracting the 235U contribution

J. Justo; H. Evangelista; A. S. Paschoa

2006-01-01

213

Team Approach to the Development of gamma ray and X ray Remote Sensing and In situ Spectroscopy for Planetary Exploration Missions.  

National Technical Information Service (NTIS)

An important part of the investigation of planetary origin and evolution is the determination of the surface composition of planets, comets, and asteroids. Measurements of discrete line X-ray and gamma ray emissions from condensed bodies in space can be u...

J. I. Trombka S. Floyd A. Ruitberg L. Evans R. Starr

1993-01-01

214

A GROUP SEPARATION METHOD FOR GAMMA SPECTROMETRY OF COMPLEX RADIONUCLIDE MIXTURES, WITH SPECIAL APPLICATION TO STAINLESS STEEL AND ITS CORROSION PRODUCTS  

Microsoft Academic Search

Short anion exchange columns coupled in series and saturated with ; chlordie, citrate, and hydroxide ions have been used for simple and vary radid ; separations of common elements in water solutions as a pretreatment for ; subanquese analysis with gamma spectrometry. A method was developed for the ; analysis of stainless steel, its corrosion products, and otaer elements present

K. Samsahl; J. Åselius; Karl F. Nakken; K. Hartiala; S. Veige; E. Diczfalusy

1958-01-01

215

The efficiency calibration and development of environmental correction factors for an in situ high-resolution gamma spectroscopy well logging system  

SciTech Connect

A Gamma Spectroscopy Logging System (GSLS) has been developed to study sub-surface radionuclide contamination. Absolute efficiency calibration of the GSLS was performed using simple cylindrical borehole geometry. The calibration source incorporated naturally occurring radioactive material (NORM) that emitted photons ranging from 186-keV to 2,614-keV. More complex borehole geometries were modeled using commercially available shielding software. A linear relationship was found between increasing source thickness and relative photon fluence rates at the detector. Examination of varying porosity and moisture content showed that as porosity increases, relative photon fluence rates increase linearly for all energies. Attenuation effects due to iron, water, PVC, and concrete cylindrical shields were found to agree with previous studies. Regression analyses produced energy-dependent equations for efficiency corrections applicable to spectral gamma-ray well logs collected under non-standard borehole conditions.

Giles, J.R.

1996-05-01

216

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

217

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

218

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

219

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

2010-12-01

220

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

221

A review of nationwide radioactivity comparisons on gamma-ray spectrometry organized by the NIRP, China.  

PubMed

Six comparison exercises on radioactivity measurement by ?-spectrometry have been organized by NIRP in China since 2007. The type of measured nuclides changed from natural to man-made over this period. A total of 188 samples were prepared and distributed to 39 different participating laboratories and 528 radionuclide assays have been performed. A perceptible laboratory performance improvement was observed with the average percentage of acceptable scores being 87% in 2008, increasing to 92% in 2012. PMID:24369889

Tuo, Fei; Xu, Cuihua; Zhang, Qing; Zhang, Jing; Zhou, Qiang; Li, Wenhong; Zhang, Jianfeng; Su, Xu

2014-05-01

222

Quantitative waste assay using gamma-ray spectrometry and computed tomography.  

National Technical Information Service (NTIS)

Simulated and real experimental data are used to investigate the use of (1) active computed tomography (ACT) to obtain images of attenuated gamma rays from a waste-canister interior; (2) passive computed tomography (PCT) to locate and determine the radioi...

H. E. Martz G. P. Roberson C. Robert-Coutant D. J. Schneberk D. C. Camp

1992-01-01

223

The in situ exobiological investigation of the Martian surface mineralogy during unmanned missions. [Abstract only  

NASA Technical Reports Server (NTRS)

An important goal of exobiological research is to determine if life arose on planets other than Earth. The only other planet known, to date, on which life may have arisen is Mars. The data suggest that the physical environment of early Mars (i.e., temperature, pressure, and radiation regimes) was suitable for life to arise. Thus far, the data also suggest that early Mars possessed sufficient quantities of the required building blocks and a number of the chemical compounds necessary for life to arise. It is not known, however, if water existed in the appropriate state (i.e., liquid) in sufficient quantities long enough for life to arise. Determining the mineralogy and components of the Martian soil through in situ analyses during missions to Mars will provide information from which an assessment can be made for the probability of the origin of life on Mars. Missions to Mars in the near future will be unmanned and capable of in situ analyses. Our studies have shown that differential thermal analysis coupled with gas chromatography (DTA/GC) is a more appropriate analytical technique than, x-ray fluorescence, x-ray diffraction, alpha-proton backscatter, gamma-ray spectrometry, differential scanning calorimetry coupled with mass spectrometry (DSC/MS), or DSC/GC to identify the mineralogy of the Martian surface material in situ. DTA/GC is an advancement over the pyrolytic techniques flown on previous missions that have supplied only limited mineralogical information (Biemann et al. 1977).

Mancinelli, Rocco L.; White, Melisa R.

1994-01-01

224

The Application of High-Resolution Gamma-Ray Spectrometry (HRGS) to Nuclear Safeguards, Nonproliferation, and Arms Control Activities  

SciTech Connect

While well-developed methodologies exist for the employment of high- resolution gamma ray spectrometry (HRGS) in determining the isotopic composition of plutonium samples, the potential capabilities of such measurements in determining the properties of nuclear materials otherwise remain largely unexploited. These measurements contain information sufficiently detailed such that not only can the isotopic composition of uranium and plutonium materials be determined, but the details of the spectrum obtained will depend reproducibly upon other factors including the total mass, density, chemical composition, and geometrical configuration of the material, and for certain materials, the elapsed time since chemical processing. The potential thus exists to obtain a `gamma-ray fingerprint` for typical containers or assemblies of nuclear material which will then serve to identify that class of item in a later confirmatory measurement. These measurements have the additional advantage that, by comparison with active interrogation techniques which usually require the introduction of some extraneous form of radiation or other intrusive activity, they are totally passive, and thus impose only minimal additional safety or regulatory burdens on the operators. In the application of these measurements to the verification of treaty-limited items, where the information acquired may be sensitive in nature, the use of the CIVET (Controlled Intrusiveness Verification Technique) approach, where a computer-based interface is employed to limit access to the information obtained, may be followed.

Kane, Walter R.; Lemley, James R.; Forman, Leon

1997-12-31

225

The influence of exogenous conditions on mobile measured gamma-ray spectrometry  

NASA Astrophysics Data System (ADS)

In the past, gamma ray measurements have been used for geological surveys and exploration using airborne and borehole logging systems. For these applications, the relationships between the measured physical parameter - the concentration of natural gamma emitters 40K, 238U and 232Th - and geological origin or sedimentary developments are well described. Based on these applications and knowledge in combination with adjusted sensor systems, gamma ray measurements are used to derive soil parameters to create detailed soil maps e.g., in digital soil mapping (DSM) and monitoring of soils. Therefore, not only qualitative but also quantitative comparability is necessary. Grain size distribution, type of clay minerals and organic matter content are soil parameters which directly influence the gamma ray emitter concentration. Additionally, the measured concentration is influenced by endogenous processes like soil moisture variation due to raining events, foggy weather conditions, or erosion and deposition of material. A time series of gamma ray measurements was used to observe changes in gamma ray concentration on a floodplain area in Central Germany. The study area is characterised by high variations in grain size distribution and occurrence of flooding events. For the survey, we used a 4l NaI(Tl) detector with GPS connection mounted on a sledge, which is towed across the field sites by a four-wheel-vehicle. The comparison of data from different time steps shows similar structures with minor variation between the data ranges and shape of structures. However, the data measured during different soil moisture contents differ in absolute value. An average increase of soil moisture of 36% leads to a decrease of Th (by 20%), K (by 29%), and U (by 41%). These differences can be explained by higher attenuation of radiation during higher soil moisture content. The different changes in nuclide concentration will also lead to varying ratios. We will present our experiences concerning the measurement under variable field conditions and their impacts on gamma ray data quality. These activities are done within the iSOIL project. iSOIL- Interactions between soil related sciences - Linking geophysics, soil science and digital soil mapping is a Collaborative Project (Grant Agreement number 211386) co-funded by the Research DG of the European Commission within the RTD activities of the FP7 Thematic Priority Environment; iSOIL is one member of the SOIL TECHNOLOGY CLUSTER of Research Projects funded by the EC.

Dierke, C.; Werban, U.; Dietrich, P.

2012-12-01

226

Microprobe sampling--photo ionization-time-of-flight mass spectrometry for in situ chemical analysis of pyrolysis and combustion gases: examination of the thermo-chemical processes within a burning cigarette.  

PubMed

A microprobe sampling device (?-probe) has been developed for in situ on-line photo ionization mass spectrometric analysis of volatile chemical species formed within objects consisting of organic matter during thermal processing. With this approach the chemical signature occurring during heating, pyrolysis, combustion, roasting and charring of organic material within burning objects such as burning fuel particles (e.g., biomass or coal pieces), lit cigarettes or thermally processed food products (e.g., roasting of coffee beans) can be investigated. Due to its dynamic changes between combustion and pyrolysis phases the cigarette smoking process is particularly interesting and has been chosen as first application. For this investigation the tip of the ?-probe is inserted directly into the tobacco rod and volatile organic compounds from inside the burning cigarette are extracted and real-time analyzed as the glowing front (or coal) approaches and passes the ?-probe sampling position. The combination of micro-sampling with photo ionization time-of-flight mass spectrometry (PI-TOFMS) allows on-line intrapuff-resolved analysis of species formation inside a burning cigarette. Monitoring volatile smoke compounds during cigarette puffing and smoldering cycles in this way provides unparalleled insights into formation mechanisms and their time-dependent change. Using this technique the changes from pyrolysis conditions to combustion conditions inside the coal of a cigarette could be observed directly. A comparative analysis of species formation within a burning Kentucky 2R4F reference cigarette with ?-probe analysis reveals different patterns and behaviors for nicotine, and a range of semi-volatile aromatic and aliphatic species. PMID:22244143

Hertz, Romy; Streibel, Thorsten; Liu, Chuan; McAdam, Kevin; Zimmermann, Ralf

2012-02-10

227

Real time in situ chemical characterization of sub-micron organic aerosols using Direct Analysis in Real Time mass spectrometry (DART-MS): the effect of aerosol size and volatility.  

PubMed

Direct Analysis in Real Time (DART) mass spectrometry is an atmospheric pressure ionization technique suitable for in situ chemical analysis of organic aerosols. Here, mass spectra are obtained by introducing a stream of nanometer-sized aerosols into the ionization region, which is an open space between the ion source and the atmospheric inlet of mass spectrometer. Model single component aerosols are used to show how the aerosol size and volatility influence the measured ion signals at different DART gas temperatures. The results show that for equivalent aerosol mass concentrations, the ion signal scales with particle surface area, with smaller diameter oleic acid aerosols yielding higher ion signals relative to larger diameter aerosols. For the aerosols of the same size, but different vapor pressures, the ion signal is larger for more volatile succinic acid aerosols than less volatile adipic and suberic acid particles. From the measured changes in aerosol size, produced by the DART source, the radial probing depth for these model aerosols range from 1 to 10 nm, the magnitude of which depends upon the physiochemical properties of the aerosols and DART gas temperature. An aerosol evaporation model reveals that the ion signal is correlated with changes in aerosol size and depends upon the total quantity of evaporated aerosol mass, consistent with a mechanism in which gas-phase molecules are first desorbed from the aerosol surface prior to ionization. The results of this work serve as a basis for future investigations of the mass spectra, ionization pathways, and probing depth of the aerosols using DART. PMID:23687648

Chan, Man Nin; Nah, Theodora; Wilson, Kevin R

2013-07-01

228

In situ breast cancer  

Microsoft Academic Search

Opinion statement  The clinical expression of in situ cancer varies widely but is usually occult. Diagnosis can be made by a variety of minimally\\u000a invasive techniques. Treatment of lobular carcinoma in situ (LCIS) is patient-directed but generally requires only close followup.\\u000a Mastectomy is the gold standard for ductal carcinoma in situ (DCIS) and is associated with low recurrence rates. Breast conservation

Ronda S. Henry-Tillman; V. Suzanne Klimberg

2000-01-01

229

The Study of Equilibrium factor between Radon-222 and its Daughters in Bangkok Atmosphere by Gamma-ray Spectrometry  

NASA Astrophysics Data System (ADS)

To study the Equilibrium between radon-222 and its daughters in Bangkok atmosphere by Gamma-ray spectrometry, air sample were collected on 48 activated charcoal canister and 360 glass fiber filters by using a high volume jet-air sampler during December 2007 to November 2008.The Spectra of gamma-ray were measured by using a HPGe (Hyper Pure Germanium Detector). In the condition of secular equilibrium obtaining between Radon-222 and its decay products, radon-222 on activated charcoal canister and its daughters on glass fiber filters collected in the same time interval were calculated. The equilibrium factor (F) in the open air had a value of 0.38 at the minimum ,and 0.75 at the maximum. The average value of equilibrium factor (F) was 0.56±0.12. Based on the results, F had variations with a maximum value in the night to the early morning and decreased in the afternoon. In addition, F was higher in the winter than in the summer. This finding corresponds with the properties of the Earth atmosphere. The equilibrium factor (F) also depended on the concentration of dust in the atmosphere. People living in Bangkok were exposed to average value of 30 Bq/m3 of Radon-222 in the atmosphere. The equilibrium factor (0.56±0.12) and the average value of Radon-222 showed that people were exposed to alpha energy from radon-222 and its daughters decay at 0.005 WL(Working Level) which is lower than the safety standard at 0.02 WL. Keywords: Radon, Radon daughters , equilibrium factor, Gamma -ray spectrum analysis ,Bangkok ,Thailand

Rujiwarodom, Rachanee

2010-05-01

230

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

231

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

232

Recognizing alpha-, beta- or gamma-substitution in pyridines by mass spectrometry.  

PubMed

A general mass spectrometric method able to recognize the site of substitution of monosubstituted pyridines is described. The method requires that the molecule under investigation forms, upon ionization and dissociation, the respective alpha-, beta- or gamma- pyridinium ion of m/z 78. Pyridinium ions are stable and common fragments of ionized and protonated pyridines and are found to function as appropriate structurally diagnostic fragment ions. They can be identified by their characteristic and nearly identical collision-induced dissociation behavior and distinguished by the combined use of two structurally diagnostic ion/molecule reactions with acetonitrile and 2-methyl-1,3-dioxolane. alpha-, beta- or gamma-substitution in pyridines can, therefore, be securely recognized via an MS-only method based on structurally diagnostic ions and by the inspection of a single molecule (no need for intracomparisons within the whole set of isomers). PMID:18563867

Corilo, Yuri E; Eberlin, Marcos N

2008-12-01

233

Gamma ray spectrometry logs as a hydrocarbon indicator for clastic reservoir rocks in Egypt.  

PubMed

Petroleum oil is an important source for the energy in the world. The Gulf of Suez, Nile Delta and South Valley are important regions for studying hydrocarbon potential in Egypt. A thorium normalization technique was applied on the sandstone reservoirs in the three regions to determine the hydrocarbon potentialities zones using the three spectrometric radioactive gamma ray-logs (eU, eTh and K% logs). The conventional well logs (gamma-ray, deep resistivity, shallow resistivity, neutron, density and sonic logs) are analyzed to determine the net pay zones in these wells. Indices derived from thorium normalized spectral logs indicate the hydrocarbon zones in petroleum reservoirs. The results of this technique in the three regions (Gulf of Suez, Nile Delta and South Valley) are in agreement with the results of the conventional well log analyses by ratios of 82%, 78% and 71% respectively. PMID:23306160

Al-Alfy, I M; Nabih, M A; Eysa, E A

2013-03-01

234

Monte Carlo Solutions for Selected Problems in Gamma-Ray Spectrometry and Nuclear Activation Analysis  

NASA Astrophysics Data System (ADS)

A comprehensive calibration of gamma-ray spectrometers cannot be obtained purely on experimental basis. Problems like self-attenuation effects, coincidence-summing effects and non-uniform source distribution (resulting e.g. from neutron self-shielding in NAA) can be efficiently solved by Monte Carlo simulation. The application of the GESPECOR code to these problems is presented and the associated uncertainty is discussed.

Sima, Octavian

2008-08-01

235

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

236

Subsurface In Situ Elemental Composition Measurements with PING  

NASA Technical Reports Server (NTRS)

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, Ann; McClanahan, Timothy; Bodnarik, Julia; Evans, Larry; Nowicki, Suzanne; Schweitzer, Jeffrey; Starr, Richard

2013-01-01

237

Quantification of gamma-aminobutyric acid in Sri Lankan tea by means of ultra performance tandem mass spectrometry.  

PubMed

Gamma-Aminobutyric acid (GABA), an important bioactive component of tea, acts as a major inhibitory neurotransmitter and is considered to influence other physiological processes in human as well as in planta. In the hereby presented study, the content of this valuable metabolite was investigated in two novel types of Ceylon Tea, explicitly "Silver Tips" and "White Tea", originating from minimally processed buds of the unique cultivar, "TRI 2043". The samples were subjected to hot water infusion, equivalent to the traditional beverage preparation procedure, and analyzed by means of hydrophilic interaction ultra performance liquid chromatography coupled to tandem mass spectrometry (HILIC LC-MS/MS). The registered GABA levels were compared with those obtained for the classic "Black Tea" and "Green Tea" samples from Sri Lanka. A high variation of GABA content was observed among the different tea types, especially in the case of "Silver Tips" and "White Tea", indicating the crucial influence of the manufacturing procedure (processing extent) on the final abundance of the bioactive component of interest. Furthermore, "White Tea" samples boasted the highest GABA concentration reported for this type of tea so far, reaching up to 50% of that characteristic of the high-priced "GABA Tea". Therefore, "White Tea" and "Silver Tips" were proved to be high quality tea with amounts of gamma-aminobutyric acid comparable with those described for similar types before. To our knowledge, this is the first report on HILIC LC-MS/MS application for the quantification of GABA and for in-depth characterization of teas from Sri Lanka. PMID:24868875

Carvalho, Elisabete; Punyasiri, P A Nimal; Somasiri, H P P Sudarshana; Abeysinghe, I Sarath B; Martens, Stefan

2014-04-01

238

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

239

Radiometric analysis of construction materials using HPGe gamma-ray spectrometry.  

PubMed

Concentrations of primordial radionuclides in common construction materials collected from the south-west coastal region of India were determined using a high-purity germanium gamma-ray spectrometer. Average specific activities (Bq kg(-1)) for (238)U((226)Ra) in cement, brick, soil and stone samples were obtained as 54 ± 13, 21 ± 4, 50 ± 12 and 46 ± 8, respectively. Respective values of (232)Th were obtained as 65 ± 10, 21 ± 3, 58 ± 10 and 57 ± 12. Concentrations of (40)K radionuclide in cement, brick, soil and stone samples were found to be 440 ± 91, 290 ± 20, 380 ± 61 and 432 ± 64, respectively. To evaluate the radiological hazards, radium equivalent activity, various hazard indices, absorbed dose rate and annual effective dose have been calculated, and compared with the literature values. Obtained data could be used as reference information to assess any radiological contamination due to construction materials in future. PMID:22887119

Khandaker, M U; Jojo, P J; Kassim, H A; Amin, Y M

2012-11-01

240

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

241

Data acquisition ATCA system for neutron and gamma-rays spectrometries  

SciTech Connect

Digital pulse processing (DPP) systems are known to have better performance than analog ones for neutron and/or gamma-ray pulses. DPP can synthesize almost any pulse response shape without the associated signal degradation which happens in a complex analog path. Measuring techniques involving detectors/spectrometers for fusion diagnostics rely on real-time algorithms, implemented in field programmable gate array (FPGA), for pulse height analysis, pulse shape discrimination, and pileup rejection of digitized pulses in real time for reduced data throughput, monitoring, and control. This article describes a data acquisition system for real-time pulse analysis based on ATCA and contains a 6 GFLPOS ix86-based control unit and a number of transient recorder (TR) modules interconnected through PCI Express links. Each TR module features (i) eight channels of 12 bit resolution with accuracy equal or higher than 10 bits, (ii) 200 Msamples/s of sampling rate achieving 400 Msamples/s in an interleaved architecture, (iii) 2 or 4 Gbytes of local memory, and (iv) two field FPGAs able to perform real-time processing algorithms.

Pereira, R.; Fernandes, A. G.; Sousa, J.; Varandas, C. A. F. [Associacao EURATOM/IST Centro de Fusao Nuclear, Instituto Superior Tecnico, 1049-001 Lisbon (Portugal)

2006-10-15

242

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

243

In situ breast cancer.  

PubMed

The clinical expression of in situ cancer varies widely but is usually occult. Diagnosis can be made by a variety of minimally invasive techniques. Treatment of lobular carcinoma in situ (LCIS) is patient-directed but generally requires only close follow-up. Mastectomy is the gold standard for ductal carcinoma in situ (DCIS) and is associated with low recurrence rates. Breast conservation therapy (BCT) has become an acceptable alternative. This choice of definitive therapy for DCIS depends largely on the ability to obtain negative margins. Any attempt at BCT should be coupled with the caveat of close postoperative long-term follow-up. Patients diagnosed with LCIS or who have a history of DCIS should be given the options for the use of tamoxifen for the reduction of subsequent development of invasive breast cancer. Risk versus benefits should be clearly defined. PMID:12057162

Henry-Tillman, R S; Klimberg, V S

2000-08-01

244

Ground gamma-ray survey of the Solforata gas discharge area, Alban Hills-Italy: a comparison between field and laboratory measurements.  

PubMed

Measurements of environmental radioactivity by HPGe gamma-spectrometry were carried out with the aim of investigating the distribution of natural radionuclides in a volcanic area and to compare two different methodologies - an in situ gamma-survey of the area and high accuracy laboratory measurements of soil samples. Results demonstrate good performance of the in situ technique, also confirmed by a correlation analysis between the results obtained by the two methodologies. A volcanic gas discharge area was chosen as the test site for the presence of natural long-lived radionuclides such as (40)K and (238)U, (235)U and (232)Th, and their decay chain members. Clear evidence of (222)Rn degassing in the area was confirmed by (226)Ra values measured by the in situ technique. Higher (40)K values measured by the in situ technique may be attributed to the presence of vegetation in the study area. PMID:22982169

Di Paolo, Federico; Plastino, Wolfango; Povinec, Pavel P; Bella, Francesco; Budano, Antonio; De Vincenzi, Mario; Laubenstein, Matthias; Ruggieri, Federico

2013-01-01

245

Gamma-ray spectrometry method used for radioactive waste drums characterization for final disposal at National Repository for Low and Intermediate Radioactive Waste--Baita, Romania.  

PubMed

The Radioactive Waste Management Department from IFIN-HH, Bucharest, performs the conditioning of the institutional radioactive waste in concrete matrix, in 200 l drums with concrete shield, for final disposal at DNDR - Baita, Bihor county, in an old exhausted uranium mine. This paper presents a gamma-ray spectrometry method for the characterization of the radioactive waste drums' radionuclides content, for final disposal. In order to study the accuracy of the method, a similar concrete matrix with Portland cement in a 200 l drum was used. PMID:24331854

Done, L; Tugulan, L C; Dragolici, F; Alexandru, C

2014-05-01

246

Methods for spectral interference corrections for direct measurements of 234U and 230Th in materials by gamma-ray spectrometry.  

PubMed

When the high-resolution gamma-ray spectrometry was used in the analysis of (234)U and (230)Th in samples, there is a much more need to correct for the measured activity results of (234)U and (230)Th mainly due to self-absorption effects and the interfering lines from (226)Ra, (235)U, (238)U and their decay products that often might be present in the samples. Therefore, in the present study, the methods for the spectral interference corrections for the analytical peaks of (234)U and (230)Th are suggested to take into account the contributions of the overlapping gamma rays to these peaks. For the method validation, direct gamma-ray spectrometric measurements were carried out using certified reference materials (CRM) by use of a 76.5 % n-type Ge detector. The activities measured for the CRM samples were corrected for spectral interferences, self-absorption and true coincidence-summing (TCS) effects. The obtained results indicate that ignoring of the contribution of the interference gamma rays to the main analytical peak at 53.2 keV of (234)U leads to a lager systematic error of 87.3-90.4 % for the measured activities of (234)U, and similarly if one ignores the contributions of the interference gamma rays to the main analytical peak at 67.7 keV of (230)Th, this leads to a much smaller systematic error of 2.1-2.7 % for the activities of (230)Th. Therefore, the required correction factors for spectral interferences to the analytical peaks of (234)U and (230)Th are not negligible and thus they should also be considered besides necessary self-absorption factors to determine more accurate activities in the samples. On the other hand, it is estimated that although the TCS effects on the main analytical peaks of both (234)U and (230)Th are negligibly small, those TCS correction factors for their interference gamma rays to these peaks should be taken into account when direct measurements are performed in a close-counting geometry condition. Otherwise, the resulted activities can have serious erroneous results for both (234)U and (230)Th while using gamma-ray spectrometry, thereby leading to inaccuracies in their derived quantities, for instance, the corresponding age determinations of the samples. PMID:19843544

Yücel, H; Solmaz, A N; Köse, E; Bor, D

2010-03-01

247

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

248

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

249

In situ pulse diffuse reflection infrared Fourier transform spectroscopy (DRIFTS) mass spectrometry study of the water-gas shift reaction on nickel(II) oxide-zinc(II) oxide catalysts.  

PubMed

The water-gas shift (WGS) reaction has been studied by pulsing carbon monoxide (CO) into a steady-state water (H2O)-Ar flow over nickel(II) oxide-zinc oxide (NiO-ZnO) catalysts using in situ diffuse reflection infrared Fourier transform spectroscopy (DRIFTS) coupled with a mass spectrometer method using the pulse technique (in situ pulse DRIFTS-MS) for different flow rates (gas hourly space velocity [GHSV] of 24,000-72,000 h(-1)) and reaction temperatures (250-350 °C). The results obtained from the in situ pulse DRIFTS-MS revealed that there are two types of water adsorption bands on the surface of the catalyst: (i) molecular adsorption (infrared [IR] bands in the 2500-3600 cm(-1) range and at 1640 cm(-1)), and (ii) dissociative adsorption at 3700 cm(-1), where carboxyl bands are formed at 1461 and 1368 cm(-1) and the gas-phase CO is adsorbed at 2187 and 2111 cm(-1) on the surface of the catalyst. After using a GHSV = 24,000 h(-1) H2O/Ar flow, we probed the existence of two active intermediates via the formation of two hydrogen production peaks. The products of hydrogen gas (H2) and carbon dioxide (CO2) had two pathways: the redox process and the associative process via the intermediate of the carboxyl group. In situ pulse DRIFTS-MS proves to be an effective approach for studying the nature of adsorbed species on the catalyst surface and the nature of the reaction product. PMID:24480281

Tang, Chih-Wei; Chuang, Steven S C

2014-02-01

250

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

251

Determination of gamma-hydroxybutyrate (GHB) in biological specimens by simultaneous extraction and chemical derivatization followed by GC-MS  

Microsoft Academic Search

Urine and chicken liver fortified with gamma-hydroxybutyrate (GHB) were pretreated with in-situ liquid-liquid extraction\\/chemical derivatization (LLE-ChD) or in-situ solid-phase extraction\\/chemical derivatization (SPE-ChD) followed by gas chromatography-mass spectrometry (GC-MS). GHB as its N,O-bis(trimethylsilyl)-trifluoroacetamide (BSTFA) derivative was recovered from urine in 23.7 % through the LLE-ChD procedure, in contrast to 60.7 % via the SPE-ChD counterpart. In the selective ion monitoring (SIM)

Sheng-Meng Wang; Yun-Seng Giang; Min-Jen Lu; Tsung-Li Kuo

252

In Situ Fabrication Technologies  

NASA Technical Reports Server (NTRS)

A manufacturing system is described that is internal to controlled cabin environments which will produce functional parts to net shape with sufficient tolerance, strength and integrity to meet application specific needs such as CEV ECLS components, robotic arm or rover components, EVA suit items, unforeseen tools, conformal repair patches, and habitat fittings among others. Except for start-up and shut-down, fabrication will be automatic without crew intervention under nominal scenarios. Off-nominal scenarios may require crew and/or Earth control intervention. System will have the ability to fabricate using both provisioned feedstock materials and feedstock refined from in situ regolith.

Rolin, Terry D.; Hammond, Monica

2005-01-01

253

In Situ Surface Characterization  

NASA Technical Reports Server (NTRS)

Operation of in situ space assets, such as rovers and landers, requires operators to acquire a thorough understanding of the environment surrounding the spacecraft. The following programs help with that understanding by providing higher-level information characterizing the surface, which is not immediately obvious by just looking at the XYZ terrain data. This software suite covers three primary programs: marsuvw, marsrough, and marsslope, and two secondary programs, which together use XYZ data derived from in situ stereo imagery to characterize the surface by determining surface normal, surface roughness, and various aspects of local slope, respectively. These programs all use the Planetary Image Geometry (PIG) library to read mission-specific data files. The programs themselves are completely multimission; all mission dependencies are handled by PIG. The input data consists of images containing XYZ locations as derived by, e.g., marsxyz. The marsuvw program determines surface normals from XYZ data by gathering XYZ points from an area around each pixel and fitting a plane to those points. Outliers are rejected, and various consistency checks are applied. The result shows the orientation of the local surface at each point as a unit vector. The program can be run in two modes: standard, which is typically used for in situ arm work, and slope, which is typically used for rover mobility. The difference is primarily due to optimizations necessary for the larger patch sizes in the slope case. The marsrough program determines surface roughness in a small area around each pixel, which is defined as the maximum peak-to-peak deviation from the plane perpendicular to the surface normal at that pixel. The marsslope program takes a surface normal file as input and derives one of several slope-like outputs from it. The outputs include slope, slope rover direction (a measure of slope radially away from the rover), slope heading, slope magnitude, northerly tilt, and solar energy (compares the slope with the Sun s location at local noon). The marsuvwproj program projects a surface normal onto an arbitrary plane in space, resulting in a normalized 3D vector, which is constrained to lie in the plane. The marsuvwrot program rotates the vectors in a surface normal file, generating a new surface normal file. It also can change coordinate systems for an existing surface normal file. While the algorithms behind this suite are not particularly unique, what makes the programs useful is their integration into the larger in situ image processing system via the PIG library. They work directly with space in situ data, understanding the appropriate image metadata fields and updating them properly. The secondary programs (marsuvwproj, marsuvwrot) were originally developed to deal with anomalous situations on Opportunity and Spirit, respectively, but may have more general applicability.

Deen, Robert G.; Leger, Patrick C.; Yanovsky, Igor

2011-01-01

254

Mass spectrometry in ionospheric research.  

PubMed

Mass spectrometry played a key role in the development of the understanding of the earth's ionosphere. Of primary importance was its use for in situ atmospheric measurements of the ion and neutral composition of the atmosphere. Mass spectrometry has also played an essential role in the laboratory measurement of critical ionospheric molecular processes. Examples of both are given. PMID:17099890

Ferguson, Eldon E

2007-01-01

255

Spectral interference corrections for the measurement of (238)U in materials rich in thorium by a high resolution gamma-ray spectrometry.  

PubMed

In this study, the spectral interferences are investigated for the analytical peaks at 63.3 keV of (234)Th and 1001.0 keV of (234m)Pa, which are often used in the measurement of (238)U activity by the gamma-ray spectrometry. The correction methods are suggested to estimate the net peak areas of the gamma-rays overlapping the analytical peaks, due to the contribution of (232)Th that may not be negligible in materials rich in natural thorium. The activity results for the certified reference materials (CRMs) containing U and Th were measured with a well type Ge detector. The self-absorption and true coincidence-summing (TCS) effects were also taken into account in the measurements. It is found that ignoring the contributions of the interference gamma-rays of (232)Th and (235)U to the mixed peak at 63.3 keV of (234)Th ((238)U) leads to the remarkably large systematic influence of 0.8-122% in the measured (238)U activity, but in case of ignoring the contribution of (232)Th via the interference gamma-ray at 1000.7 keV of (228)Ac to the mixed peak at 1001 keV of (234m)Pa ((238)U) results in relatively smaller systematic influence of 0.05-3%, depending on thorium contents in the samples. The present results showed that the necessary correction for the spectral interferences besides self-absorption and TCS effects is also very important to obtain more accurate (238)U activity results. Additionally, if one ignores the contribution of (232)Th to both (238)U and (40)K activities in materials, the maximum systematic influence on the effective radiation dose is estimated to be ~6% and ~1% via the analytical peaks at 63.3 and 1001 keV for measurement of the (238)U activity, respectively. PMID:19683454

Yücel, H; Solmaz, A N; Köse, E; Bor, D

2009-11-01

256

In situ measurement system  

DOEpatents

A multipurpose in situ underground measurement system comprising a plurality of long electrical resistance elements in the form of rigid reinforcing bars, each having an open loop hairpin configuration of shorter length than the other resistance elements. The resistance elements are arranged in pairs in a unitized structure, and grouted in place in the underground volume. Measurement means are provided for obtaining for each pair the electrical resistance of each element and the difference in electrical resistance of the paired elements, which difference values may be used in analytical methods involving resistance as a function of temperature. A scanner means sequentially connects the resistance-measuring apparatus to each individual pair of elements. A source of heating current is also selectively connectable for heating the elements to an initial predetermined temperature prior to electrical resistance measurements when used as an anemometer.

Lord, D.E.

1980-11-24

257

Gamma radiation and dose rate investigations on the Adriatic islands of magmatic origin.  

PubMed

Natural radioactivity of Middle-Adriatic Sea islands and islets was measured. Gamma spectrometric measurements, both in situ and in laboratory, as well as radon measurements in the seawater were performed. Activity concentrations and the associated dose rates due to naturally occurring (232)Th, (238)U and (40)K radioisotopes were determined. Dose rates calculated from in situ gamma spectrometry are in correlation with dose rates calculated from activity concentrations measured in collected samples of pebbles and rocks. In situ gamma ray spectrometry in the seawater has been performed, showing activity concentration of 220 and 240 Bq m(-3) for (214)Bi and (214)Pb, respectively due to the presence of magmatic rocks in the seabed. The radium equivalent activity varied from 13 to 53 Bq kg(-1). These values are lower than the limit values, indicating that the radiation hazard is not significant. The highest mean activity concentrations of naturally occurring radionuclides in rock samples collected were found on the islands of magmatic origin. PMID:20085897

Petrinec, Branko; Frani?, Zdenko; Leder, Nenad; Tsabaris, Christos; Bituh, Tomislav; Marovi?, Gordana

2010-06-01

258

Regional radiometric study over the east of Homs City depending on carborne gamma-ray spectrometry survey.  

National Technical Information Service (NTIS)

The purpose of regional carborne gamma-ray survey over the east of Homs city is to determine the ground concentration of potassium, uranium and thorium. In the other hand, collecting essential information for future monitoring of any suspected leakage or ...

M. Aissa

1994-01-01

259

Construction and Testing of a Neutron and Gamma Spectrometry System Using Pulse Shape Discrimination with an Organic Scintillator.  

National Technical Information Service (NTIS)

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 sc...

R. S. Pope

1993-01-01

260

A nondestructive method based on gamma spectrometry for the measurements of plutonium hold-up or plutonium wastes  

Microsoft Academic Search

With respect to in-plant holdup and wastes, plutonium quantities are measured in most cases by nondestructive methods such as neutron counting, gamma-photon counting, and infrared detection. These methods are often imperfect for various reasons: difficult access to sample, highly radioactive background, screens, etc. It is therefore of interest to develop other methods in order to check the results from these

J. Morel; B. Chauvenet; M. Etcheverry; L. Louppe; J. Monier

1987-01-01

261

Performance of cerium-doped Gd3Al2Ga3O12 (GAGG:Ce) scintillator in gamma-ray spectrometry  

NASA Astrophysics Data System (ADS)

Performance of cerium-doped Gd3Al2Ga3O12 (GAGG:Ce) scintillator in gamma-ray spectrometry has been investigated. The measurements of two samples of GAGG:Ce cover the tests of emission spectra (maximum of emission at about 530 nm), light output, non-proportionality, energy resolution, time resolution and decay time of light pulses. We compare the results with commonly known scintillators, such as NaI(Tl), LSO, LuAG etc. The results show that GAGG:Ce has a high light yield of about 33000 ph/MeV as measured with Hamamatsu S3590-18 Si PiN photodiode [1]. The total energy resolution for 662 keV gamma-rays from 137Cs source is equal to about 6%, whereas intrinsic resolution is equal to 5.2%. Additionally, we made basic measurements of photoelectron yield, non-proportionality and total energy resolution of small sample (5×5×5 mm3) of GAGG:Ce crystal coupled to Hamamatsu MPPC array (6×6 mm2). The results show that the performance of GAGG:Ce measured with the MPPC array are similar to those measured with the PMT.

Iwanowska, Joanna; Swiderski, Lukasz; Szczesniak, Tomasz; Sibczynski, Pawel; Moszynski, Marek; Grodzicka, Martyna; Kamada, Kei; Tsutsumi, Kousuke; Usuki, Yoshiyuki; Yanagida, Takayuki; Yoshikawa, Akira

2013-06-01

262

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...

263

In Situ Nuclear Characterization Infrastructure  

SciTech Connect

To be able to evolve microstructure with a prescribed in situ process, an effective measurement infrastructure must exist. This interdisciplinary infrastructure needs to be developed in parallel with in situ sensor technology. This paper discusses the essential elements in an effective infrastructure.

James A. Smith; J. Rory Kennedy

2011-11-01

264

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

265

In situ mercury stabilization  

SciTech Connect

BNL Royalty Project Internal Status Report. The funds from the allotment of royalty income were used to experimentally explore feasibility of related, potential new techniques based on the Environmental Sciences Department successful technology licensed for the ex situ treatment of mercury. Specifically, this work is exploring the concept of using Sulfur Polymer Cement (SPC) in an in situ application to stabilize and/or remove mercury (Hg) from surficial soil. Patent disclosure forms have been filed for this process. Soil was artificially spiked with 500 ppm Hg and a series of experiments were set up in which SPC rods were placed in the center of a mass of this soil. Some experiments were conducted at 20 C and others at 50 C. After times ranging from 11 to 24 days, these experiments were opened, photographed and the soil was sampled from discrete locations in the containers. The soil and SPC samples were analyzed for Fe and Hg by x-ray fluorescence. The Hg profile in the soil was significantly altered, with concentrations along the outer edge of the soil reduced by as much as 80% from the starting concentration. Conversely, closer to the treatment rod containing SPC, concentrations of Hg were significantly increased over the original concentration. Preliminary results for elevated temperature sample are shown graphically in Figure 2. Apparently the Hg had migrated toward the SPC and reacted with sulfur to form Hg S. This appears to be a reaction between gaseous phases of both S and Hg, with Hg having a greater vapor pressure. The concentration of low solubility HgS (i.e., low leaching properties) developed within 11 days at 50 C and 21 days at 20 C, confirming the potential of this concept.

Fuhrmann, M.; Kalb, P.; Adams, J.

2004-09-01

266

Experimental study on neptunium migration under in situ geochemical conditions  

NASA Astrophysics Data System (ADS)

Results are reported for migration experiments performed with Np under in situ geochemical conditions over a range of groundwater flow rates in columns of crushed rock in a specially designed facility at the 240-level of the Underground Research Laboratory (URL) near Pinawa, Manitoba, Canada. This laboratory is situated in an intrusive granitic rock formation, the Lac du Bonnet batholith. Highly altered granitic rock and groundwater were obtained from a major subhorizontal fracture zone at a depth of 250 m in the URL. The granite was wet-crushed and wet-sieved with groundwater from this fracture zone. The 180-850-?m size fraction was selected and packed in 20-cm long, 2.54-cm in diameter Teflon™-lined stainless steel columns. Approximately 30-ml vols of groundwater containing 3HHO and 237Np were injected into the columns at flow rates of 0.3, 1, and 3 ml/h, followed by elution with groundwater, obtained from the subhorizontal fracture, at the same flow rates, for a period of 95 days. Elution profiles for 3HHO were obtained, but no 237Np was detected in the eluted groundwater. After terminating the migration experiments, the columns were frozen, the column material was removed and cut into twenty 1-cm thick sections and each section was analyzed by gamma spectrometry. Profiles of 237Np were obtained for the three columns. A one-dimensional transport model was fitted to the 3HHO breakthrough curves to obtain flow parameters for this experiment. These flow parameters were in turn applied to the 237Np concentration profiles in the columns to produce sorption and dispersion coefficients for Np. The results show a strong dependence of retardation factors ( Rf) on flow rate. The decrease in the retarded velocity of the neptunium ( Vn) varied over one order of magnitude under the geochemical conditions for these experiments.

Kumata, M.; Vandergraaf, T. T.

1998-12-01

267

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

2012-07-01

268

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.

BEGIN:VCARD VERSION:2.1 FN:Darryl Leja N:Leja;Darryl ORG:National Human Genome Research Institute REV:2005-04-04 END:VCARD

2005-04-04

269

In-situ chemical imager  

NASA Technical Reports Server (NTRS)

A variety of in-situ planetary exploration tasks such as particulate analysis or life detection require a tool with a capability for combined imaging and chemical analysis with sub-micron spatial resolution.

Kossakovski, D. A.; Bearman, G. H.; Kirschvink, J. L.

2000-01-01

270

Assessing soil erosion at landscape level: A step forward in the up-scaling of 137Cs measurements through the use of in-situ lanthanum bromide scintillator  

NASA Astrophysics Data System (ADS)

Measuring Fallout Radionuclides (FRN), in particular 137Cs, is a well-established method to estimate soil erosion and deposition in agricultural landscapes. While extremely sensitive, laboratory based gamma-ray spectrometry requires careful handling and preparation of measurement samples with a lengthy measuring time (~1 day), In-situ gamma-ray spectrometry can give near instantaneous results, allowing prompt decisions to be made and identification of critical spots of soil erosion, while the equipment is in the field. The aim of this investigation was to compare the precision of the in-situ FRN measurements, made by a cost-effective lanthanum bromide (LaBr3 (Ce)) scintillation detector of 137Cs against those from conventional (high-purity germanium HPGe detector) but laborious laboratory based gamma-ray spectrometry for assessing soil erosion. As preliminary test, five cores of a gleyic Cambisol - per increments of 5 cm until 1 m depth - were collected at the experimental research station of the Austrian Agency for Health and Food Safety located in Grabenegg 130 km west of Vienna. Three soil cores were sampled at the study site and, in the vicinity of this experimental site, two additional cores were collected at two different undisturbed reference sites. Laboratory gamma analyses were carried out during 50 000 seconds using a HPGe coaxial detector. The gamma measurements performed at the laboratory confirmed the undisturbed status of the two selected reference sites (i.e. exponential decrease with depth of the 137Cs content). Using the surface area of the sampling tool, the 137Cs areal activities of the cores sampled in the study site have been established at 2134±465 Bq m-2, 1835±356 Bq m-2 and 2553±340 Bq m-2, and, for the two reference sites at 3221±444 Bq m-2 and 3946±527 Bq m-2. At the same location and prior to collect the five soil cores, in-situ measurements using a lanthanum bromide (LaBr3 (Ce)) scintillator were performed. The detector was placed at 2 cm above ground and each measurement was conducted for 900 seconds. A significant positive correlation (i.e. R2=0.82; p < 0.001) has been established between the 137Cs areal activities obtained with the in-situ and laboratory based measurements. The first results relating to in-situ measurement of 137Cs offer an exciting potential for the application of FRN measurements and their up-scaling in the framework of soil erosion assessments at the landscape level. This includes cost, time, and portability, the potential to work in remote areas, pre-screening to develop more effective sampling strategies and rapid repeat surveys. This work is still in its initial stage and more research is required to validate this innovative in-situ technique.

Gonsalves, Basil C.; Darby, Iain G.; Toloza, Arsenio; Mabit, Lionel; Kaiser, Ralf B.; Dercon, Gerd

2014-05-01

271

In Situ Activation of Microcapsules  

NASA Technical Reports Server (NTRS)

Disclosed are microcapsules comprising a polymer shell enclosing two or more immiscible liquid phases in which a drug, or a prodrug and a drug activator are partitioned into separate phases. or prevented from diffusing out of the microcapsule by a liquid phase in which the drug is poorly soluble. Also disclosed are methods of using the microcapsules for in situ activation of drugs where upon exposure to an appropriate energy source the internal phases mix and the drug is activated in situ.

Morrison, Dennis R. (Inventor); Mosier, Benjamin (Inventor)

2000-01-01

272

Iron and titanium distribution on the moon from orbital gamma ray spectrometry with implications for crustal evolutionary models  

NASA Astrophysics Data System (ADS)

A set of Fe and Ti maps and regional values are obtained from the Apollo 15 and 16 orbital gamma ray data by energy band analysis. High-Ti basalts predominate the early and late stages of mare volcanism with high-Fe basaltic volcanism in the interim. The first evidence of a high-Ti-KREEP basalt association is found in the Aristarchus region. A N-S asymmetry for Fe and Ti in the east limb and farside highlands complicates the E-W asymmetry for Th but substantiates crustal inhomogeneity. The observed crustal inhomogeneity adds an additional objection to the primitive source model for crustal evolution. The high-Ti-KREEP basalt association and the general trend of decreasing mare basalt Ti with time lend support to the cumulate source model; however, this model cannot account for young, high-Ti maria. The dynamic assimilation model better accounts for chemical variations observed on the moon.

Davis, P. A.

1980-06-01

273

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

PubMed

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, effects of sample heating by the proton beam, background estimation) which were encountered during this study are discussed. Sensitivity and reproducibility of the determinations, and homogeneity of the coal samples with respect to fluorine contents by analysis of variance were investigated. The present data are also compared with the few published values for these reference samples, including other PIGE data. The use of synthetic standards and spiked samples in the present study suggested that the PIGE method was more accurate than other techniques. PMID:18966506

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

1996-03-01

274

Method for in situ determination of the cation exchange capacities of subsurface formations  

Microsoft Academic Search

A method is disclosed for the in situ examination of each subsurface formation penetrated by a borehole to ascertain the cation exchange capacity of such formations within a geological region. Natural gamma ray logging is used to develop signals functionally related to the total gamma radiation and to the potassium -40, uranium and thorium energy-band radiations. A first borehole is

W. H. Fertl; D. W. Welker

1981-01-01

275

Nanoparticles laden in situ gel for sustained ocular drug delivery.  

PubMed

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. PMID:23833523

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

2013-04-01

276

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

277

TRIO-01 experiment: in-situ tritium recovery results  

SciTech Connect

The TRIO-01 experiment was designed to test in-situ tritium recovery and heat transfer performance of a candidate solid breeder, ..gamma..-LiAlO/sub 2/. The results showed that nearly all the tritium generated was recovered. Only < 0.1 wppM tritium remained in the solid after irradiation testing. The heat transfer performance showed that temperature profiles can be effectively controlled.

Clemmer, R.G.; Finn, P.A.; Billone, M.C.; Misra, B.; Greenwood, L.R.; Dyer, F.F.; Dudley, I.T.; Bate, L.C.; Clemmer, E.D.; Fisher, P.W.

1983-01-01

278

Triplex in-situ hybridization  

US Patent & Trademark Office Database

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.

2002-10-08

279

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

280

Nanoparticles laden in situ gel of levofloxacin for enhanced ocular retention.  

PubMed

Availability of proper concentration of medicament on to the corneal surface is a challenging task. Many novel formulations, i.e. hydrogels, nanoparticles, ocuserts, etc. had been tested to improve ocular bioavailability, out of which our group found, in situ gel and polymeric nanoparticle are the most interesting approach to achieve ocular retention. We found that in situ gel stay only for 12?h and poly(lactic-co-glycolic acid (PLGA) nanoparticles are non mucoadhesive in nature so we try to combine both these formulations and termed it as "Nanoparticle laden in situ gel". Here we prepare nanoparticle laden in situ gel containing levofloxacin encapsulated PLGA nanoparticle, incorporated in chitosan in situ gel and evaluated its ocular retention by gamma scintigraphy in rabbits. The observations of acquired gamma camera images showed good retention over the entire precorneal area. From static and dynamic gamma scintigraphy evaluation, we can be interpret that developed nanoparticle laden in situ gel formulation cleared at a very slow rate and remained at corneal surface for longer duration than marketed formulation, in situ gel and nanosuspension alone. PMID:24044648

Gupta, Himanshu; Aqil, M; Khar, R K; Ali, Asgar; Bhatnagar, Aseem; Mittal, Gaurav

2013-01-01

281

Determination of gamma-hydroxybutyric acid in human urine by capillary electrophoresis with indirect UV detection and confirmation with electrospray ionization ion-trap mass spectrometry.  

PubMed

Gamma-hydroxybutyric acid (GHB), a minor metabolite or precursor of gamma-aminobutyric acid (GABA), acts as a neurotransmitter/neuromodulator via binding to GABA receptors and to specific presynaptic GHB receptors. Based upon the stimulatory effects, GHB is widely abused. Thus, there is great interest in monitoring GHB in body fluids and tissues. We have developed an assay for urinary GHB that is based upon liquid-liquid extraction and capillary zone electrophoresis (CZE) with indirect UV absorption detection. The background electrolyte is composed of 4 mM nicotinic acid (compound for indirect detection), 3 mM spermine (reversal of electroosmosis) and histidine (added to reach a pH of 6.2). Having a 50 microm I.D. capillary of 40 cm effective length, 1-octanesulfonic acid as internal standard, solute detection at 214 nm and a diluted urine with a conductivity of 2.4 mS/cm, GHB concentrations > or = 2 microg/ml can be detected. Limit of detection (LOD) and limit of quantitation (LOQ) were determined to be dependent on urine concentration and varied between 2-24 and 5-60 microg/ml, respectively. Data obtained suggest that LOD and LOQ (both in microg/ml) can be estimated with the relationships 0.83 kappa and 2.1 kappa, respectively, where kappa is the conductivity of the urine in mS/cm. The assay was successfully applied to urines collected after administration of 25 mg sodium GHB/kg body mass. Negative electrospray ionization ion-trap tandem mass spectrometry was used to confirm the presence of GHB in the urinary extract via selected reaction monitoring of the m/z 103.1-->m/z 85.1 precursor-product ion transition. Independent of urine concentration, this approach meets the urinary cut-off level of 10 microg/ml that is required for recognition of the presence of exogenous GHB. Furthermore, data obtained with injection of plain or diluted urine indicate that CZE could be used to rapidly recognize GHB amounts (in microg/ml) that are > or = 4 kappa. PMID:12685588

Baldacci, Andrea; Theurillat, Regula; Caslavska, Jitka; Pardubská, Helena; Brenneisen, Rudolf; Thormann, Wolfgang

2003-03-21

282

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

283

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

284

Oldest biliary endoprosthesis in situ  

PubMed Central

The advantages of endoscopic retrograde cholangiopancreatography over open surgery have made it the predominant method of treating patients with choledocholithiasis. After sphincterotomy, however, 10%-15% of common bile duct stones cannot be removed with a basket or balloon. The methods for managing “irretrievable stones” include surgery, mechanical lithotripsy, intraductal or extracorporeal shock wave lithotripsy and biliary stenting. The case presented was a referred 82-year-old Caucasian woman with a 7-year-old plastic biliary endoprosthesis in situ. To the best of our knowledge the examined endoprosthesis is the oldest endoprosthesis in situ reported in the literature. Endoscopic biliary endoprosthesis placement remains a simple and safe procedure for patients with stones that are difficult to manage by conventional endoscopic methods and for patients who are unfit for surgery or who are high surgical risks. To date no consensus has been reached regarding how long a biliary prosthesis should remain in situ. Long-term biliary stenting may have a role in selected elderly patients if stones extraction has failed because the procedure may prevent stones impaction and cholangitis.

Consolo, Pierluigi; Scalisi, Giuseppe; Crino, Stefano F; Tortora, Andrea; Giacobbe, Giuseppa; Cintolo, Marcello; Familiari, Luigi; Pallio, Socrate

2013-01-01

285

Authenticity assessment of gamma- and delta-decalactone from prunus fruits by gas chromatography combustion/pyrolysis isotope ratio mass spectrometry (GC-C/P-IRMS).  

PubMed

Authenticity assessment of gamma-decalactone (1) and delta-decalactone (2) from peach (Prunus persica var. persica), apricot (Prunus armeniaca), and nectarine (Prunus persica var. nectarina) was performed using gas chromatography-isotope ratio mass spectrometry (GC-IRMS) in the combustion (C) and pyrolysis (P) mode. In addition, commercially available synthetic (nature-identical) 1 and 2 as well as biotechnologically produced samples (declared to be "natural") were characterized by their delta(2)H(V)(-)(SMOW) and delta(13)C(V)(-)(PDB) values. For the Prunus fruits under study, rather narrow ranges of delta(13)C(V)(-)(PDB) and delta(2)H(V)(-)(SMOW) data of 1, varying from - 34.6 per thousand to - 38.4 per thousand and -160 per thousand to -206 per thousand, respectively, were obtained. Synthetic references of 1 showed delta(13)C(V)(-)(PDB) and delta(2)H(V)(-)(SMOW) data ranging from -27.4 per thousand to -28.3 per thousand and -151 per thousand to -184 per thousand, respectively. Samples of 1 declared to be "natural" exhibited ranges from -28.1 per thousand to -29.2 per thousand and -192 per thousand to -286 per thousand for delta(13)C(V)(-)(PDB) and delta(2)H(V)(-)(SMOW), respectively. For 2 from peach, apricot, and nectarine, delta(13)C(V)(-)(PDB) values ranging from -34.0 per thousand to -37.9 per thousand were determined; the delta(2)H(V)(-)(SMOW) values ranged from -171 per thousand to -228 per thousand. The delta(13)C(V)(-)(PDB) and delta(2)H(V)(-)(SMOW) data for synthetic 2 were -28.2 per thousand and -171 per thousand, respectively, that is, similar to those of 2 from "natural" origin, ranging from -27.7 per thousand to -30.1 per thousand and -185 per thousand to -230 per thousand for delta(13)C(V)(-)(PDB) and delta(2)H(V)(-)(SMOW), respectively. GC-C/P-IRMS allowed clear-cut analytical differentiation of the synthetic and "ex-plant" origin of 1 and 2, whereas narrow ranges of delta(13)C(V)(-)(PDB) and delta(2)H(V)(-)(SMOW) data were found for samples of synthetic and "natural" origin. PMID:15969525

Tamura, Hirotoshi; Appel, Markus; Richling, Elke; Schreier, Peter

2005-06-29

286

In Situ Mosaic Brightness Correction  

NASA Technical Reports Server (NTRS)

In situ missions typically have pointable, mast-mounted cameras, which are capable of taking panoramic mosaics comprised of many individual frames. These frames are mosaicked together. While the mosaic software applies radiometric correction to the images, in many cases brightness/contrast seams still exist between frames. This is largely due to errors in the radiometric correction, and the absence of correction for photometric effects in the mosaic processing chain. The software analyzes the overlaps between adjacent frames in the mosaic and determines correction factors for each image in an attempt to reduce or eliminate these brightness seams.

Deen, Robert G.; Lorre, Jean J.

2012-01-01

287

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

288

In-situ measurement system  

DOEpatents

A multipurpose in situ underground measurement system comprising a plurality of long electrical resistance elements in the form of rigid reinforcing bars, each having an open loop "hairpin" configuration of shorter length than the other resistance elements. The resistance elements are arranged in pairs in a unitized structure, and grouted in place in the underground volume. The electrical resistance of each element and the difference in electrical resistance of the paired elements are obtained, which difference values may be used in analytical methods involving resistance as a function of temperature. A scanner sequentially connects the resistance-measuring apparatus to each individual pair of elements. A source of heating current is also selectively connectable for heating the elements to an initial predetermined temperature prior to electrical resistance measurements when used as an anemometer.

Lord, David E. (Livermore, CA)

1983-01-01

289

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

290

Amplification of chromosomal DNA in situ  

DOEpatents

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 (CGH) procedures.

Christian, Allen T. (Tracy, CA); Coleman, Matthew A. (Livermore, CA); Tucker, James D. (Livermore, CA)

2002-01-01

291

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

2009-07-01

292

A Micromachined Electret-Based Transponder for In Situ Radiation Measurement  

Microsoft Academic Search

This letter reports on the development of a micromachined passive transponder for in situ measurement of ionizing radiation. gamma-ray exposure is remotely measured by monitoring the resonance frequency change correlated with a change in the surface charge of an electret. This is achieved through a micromachined capacitor with a movable plate that is partially filled with a Teflon electret and

C. Son; B. Ziaie

2006-01-01

293

Aromatase and in situ estrogen production in DCIS (ductal carcinoma in situ) of human breast.  

PubMed

Ductal carcinoma in situ or DCIS belongs to intraductal proliferative lesions, which are a group of cytologically and architecturally diverse ductal proliferations, typically originating from the terminal duct-lobular units. In these intraductal proliferative diseases, estrogens are considered to be involved in the progression of the disease especially from ductal non-neoplastic hyperplasia to DCIS and possibly development of invasive carcinoma from DCIS. Estrogen receptor (ER) alpha is abundantly expressed in atypical ductal hyperplasia and low grade DCIS. Suppression of estrogenic actions using tamoxifen resulted in inhibition of recurrence of DCIS and/or of progression into invasive carcinoma. Intratumoral estrogen concentration in DCIS determined by liquid chromatography/electrospray tandem mass spectrometry is significantly higher than that in non-neoplastic breast tissues with statistically not lower than that in invasive carcinoma. Aromatase mRNA expression in both stromal and parenchymal cells of DCIS determined by quantitative RT-PCR following laser capture microdissection was also much higher than that in non-neoplastic breast, although lower than that in invasive carcinoma. Immunohistochemistry of aromatase also revealed the similar patterns of immunolocalization as in invasive carcinoma. Aromatase is overexpressed in noninvasive breast malignancies including DCIS and results in elevated concentrations of intratumoral estradiol. These findings could provide the scientific rationale as to employing aromatase inhibitors in the management of ER positive DCIS patients. PMID:19782135

Sasano, Hironobu; Miki, Yasuhiro; Shibuya, Rie; Suzuki, Takashi

2010-02-28

294

The architecture of outer dynein arms in situ.  

PubMed

Outer dynein arms, the force generators for axonemal motion, form arrays on microtubule doublets in situ, although they are bouquet-like complexes with separated heads of multiple heavy chains when isolated in vitro. To understand how the three heavy chains are folded in the array, we reconstructed the detailed 3D structure of outer dynein arms of Chlamydomonas flagella in situ by electron cryo-tomography and single-particle averaging. The outer dynein arm binds to the A-microtubule through three interfaces on two adjacent protofilaments, two of which probably represent the docking complex. The three AAA rings of heavy chains, seen as stacked plates, are connected in a striking manner on microtubule doublets. The tail of the alpha-heavy chain, identified by analyzing the oda11 mutant, which lacks alpha-heavy chain, extends from the AAA ring tilted toward the tip of the axoneme and towards the inside of the axoneme at 50 degrees , suggesting a three-dimensional power stroke. The neighboring outer dynein arms are connected through two filamentous structures: one at the exterior of the axoneme and the other through the alpha-tail. Although the beta-tail seems to merge with the alpha-tail at the internal side of the axoneme, the gamma-tail is likely to extend at the exterior of the axoneme and join the AAA ring. This suggests that the fold and function of gamma-heavy chain are different from those of alpha and beta-chains. PMID:17391698

Ishikawa, Takashi; Sakakibara, Hitoshi; Oiwa, Kazuhiro

2007-05-18

295

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...

296

Is It Really Duct Carcinoma In Situ?  

Microsoft Academic Search

To the question “Is axillary node staging required in patients with duct carcinoma in situ (DCIS) of the breast?” there are two possible responses: a short answer and a long one. The short answer is a simple and unambiguous “no.” By definition, neither DCIS nor any in situ cancer can possibly metastasize and the treatment is therefore local. The appropriate

Hiram S. Cody III; Nancy Klauber-DeMore; Patrick I. Borgen; Kimberly J. Van Zee

2001-01-01

297

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

298

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

299

Multiple NEO Rendezvous, Reconnaissance and In Situ Exploration  

NASA Astrophysics Data System (ADS)

We propose a two spacecraft mission (Mother Ship and Small Body Lander) rendezvous with multiple Near Earth Objects (NEO). This two spacecraft mission mimics the likely architecture approach that human explorers will use: a “mother ship”(MS) designed to get from Earth to the NEO and a “Small Body Lander”(SBL) that performs in situ investigation on or close to the NEO’s surface. The MS carries the SBL to the target NEO. Once at the target NEO, the MS conducts an initial reconnaissance in order to produce a high resolution map of the surface. This map is used to identify coordinates of interest which are sent to the SBL. The SBL un-docks from the MS to rendezvous with the NEO and collect data. Landings are possible, though the challenges of anchoring to the NEO surface are significant. The SBL design is flexible and adaptable, enabling science data collection on or near the surface. After surface investigations are completed on the first NEO, the SBL will return and autonomously rendezvous and dock with the MS. The MS then goes to the next NEO target. During transit to the next NEO, the SBL could be refueled by the MS, a TRL8 capability demonstrated on the DARPA/NASA Orbital Express mission in 2007, or alternately sized to operate without requiring refueling depending on the mission profile. The mission goals are to identify surface hazards; quantify engineering boundary conditions for future human visits, and identify resources for future exploitation. The mission goals will be accomplished through the execution of key mission objectives: (1) high-resolution surface topography; (2) surface composition and mineralogy; (3) radiation environment near NEO; and (4) mechanical properties of the surface. Essential SBL instruments include: a) LIDAR (Obj. 1); b) 3D, high- resolution hyperspectral imaging cameras (Obj. 2); c) radiation sensor package (Obj. 3); and d) strain gauges (Obj. 4). Additional or alternative instruments could include: e) x-ray fluorescence or laser-induced breakdown spectroscopy (LIBS) sensor package (Obj. 2); f) gamma ray/neutron spectrometry package (Obj. 2); and g) radiometer package (to address variations in thermal environment). The ability to reach, survey, sample, and analyze multiple NEOs at close proximity is an enormous capability that can enable NASA to rapidly achieve the primary Exploration Precursor Robotic Mission (xPRM) Program goal of characterizing NEOs for future human exploration. Instead of launching multiple dedicated missions to each NEO of interest, a multi-NEO sortie mission can be planned and executed to achieve the same mission objectives with one launch, dramatically reducing the cost of NEO exploration. Collectively, our NEO Exploration System Architecture provides solutions for a wide variety of exploration activities using a common spacecraft bus and common core instrumentation for the spacecraft. This engineering consistency will substantially improve the probability of mission success, increase the likelihood of maintaining an aggressive launch schedule, and decrease the total cost of multiple missions. NASA successfully used this approach with the robotic precursors leading up to the Apollo missions, and we see significant benefits from this same programmatic approach for the xPRM program.

Klaus, K.; Elsperman, M. S.; Cook, T.; Smith, D.

2010-12-01

300

30 CFR 785.22 - In situ processing activities.  

Code of Federal Regulations, 2010 CFR

...OF MINING § 785.22 In situ processing activities...reclamation operations utilizing in situ processing activities...for operations involving in situ processing activities shall...radioactive gases, solids, or liquids constituting a fire,...

2010-07-01

301

30 CFR 828.11 - In situ processing: Performance standards.  

Code of Federal Regulations, 2010 CFR

...and this section. (b) In situ processing activities...Each person who conducts in situ processing activities...radioactive gases, solids, or liquids constituting a fire, health...Each person who conducts in situ processing activities...

2010-07-01

302

30 CFR 785.22 - In situ processing activities.  

Code of Federal Regulations, 2010 CFR

...OF MINING § 785.22 In situ processing activities...reclamation operations utilizing in situ processing activities...for operations involving in situ processing activities shall...radioactive gases, solids, or liquids constituting a fire,...

2009-07-01

303

30 CFR 828.11 - In situ processing: Performance standards.  

Code of Federal Regulations, 2010 CFR

...and this section. (b) In situ processing activities...Each person who conducts in situ processing activities...radioactive gases, solids, or liquids constituting a fire, health...Each person who conducts in situ processing activities...

2009-07-01

304

In situ ion-beam analysis and modification of sol-gel zirconia thin films  

SciTech Connect

We report the investigation of ion-beam-induced densification of sol-gel zirconia thin films via in situ ion backscattering spectrometry. We have irradiated three regions of a sample with neon, argon, and krypton ions. For each ion species, a series of irradiation and analysis steps were performed using an interconnected 3 MV tandem accelerator. The technique offers the advantages of minimizing the variation of experimental parameters and sequentially monitoring the densification phenomenon with increasing ion dose.

Levine, T.E. [Cornell Univ., Ithaca, NY (United States). Dept. of Materials Science and Engineering; Yu, Ning; Kodali, P.; Walter, K.C.; Nastasi, M.; Tesmer, J.R.; Maggiore, C.J. [Los Alamos National Lab., NM (United States); Mayer, J.W. [Arizona State Univ., Tempe, AZ (United States). Dept. of Chemical, Bio and Materials Science Engineering

1995-05-01

305

In-situ and ex-situ investigations of pulsed laser ablation of Y target  

Microsoft Academic Search

High purity yttrium was ablated by using frequency quadrupled ultra-violet pulses of a Nd:YAG laser (?=266nm, ?FWHM=7ns) with power density of about 1GW\\/cm2. Laser ablation process was studied using in-situ mass spectrometry of the ablated species in combination with ex-situ analyses of both target surface and deposited films. An increase on the Y ablation rate was found at the beginning,

A. Lorusso; F. Gontad; A. Perrone

2011-01-01

306

Fast in situ copolymerization of PET\\/PEN blends by ultrasonically-aided extrusion  

Microsoft Academic Search

An ultrasonically-aided extrusion process was developed for fast in situ compatibilization of immiscible polymer blends. PET, PEN, and their 50\\/50 blend were ultrasonically extruded at various amplitudes. PET underwent homopolymerization and degradation, respectively, at ultrasonic amplitudes of 7.5 and 10 ?m, while PEN underwent degradation at amplitudes of 5, 7.5, and 10 ?m. MALDI-TOF mass spectrometry revealed greater amounts of hydroxyl and

Kaan Gunes; Avraam I. Isayev; Xiaopeng Li; Chrys Wesdemiotis

2010-01-01

307

In situ study on CO 2 evolution at lithium-ion battery cathodes  

Microsoft Academic Search

This study based on in situ differential electrochemical mass spectrometry (DEMS) in model cells with Li(Ni, Co, Al)O2 and Li(Ni, Mn, Co)O2 cathodes highlights various influence parameters on CO2 evolution in lithium-ion batteries. The amount of CO2 formation is increased by high temperatures and cell voltages, while the addition of vinylene carbonate (VC) decreases it. Lithium carbonate present in the

J. Vetter; M. Holzapfel; A. Wuersig; W. Scheifele; J. Ufheil; P. Novák

2006-01-01

308

A Deep-Sea Mass Spectrometer Instrument for Long-Term, In Situ Biogeochemical Monitoring  

Microsoft Academic Search

Mass spectrometry has been a major analytical tool for more than 100 years, but it has rarely been used to monitor the environment in situ. Furthermore, a deep-water instrument is even more challenging due to a lack of an effective membrane-introduction interface and an efficient high-vacuum system that will work remotely for long periods at very high pressure. Being able

A. Bossuyt; G. M. McMurtry

2004-01-01

309

Small Diameter Pumps for In Situ Leaching.  

National Technical Information Service (NTIS)

This citation summarizes a one-page announcement of technology available for utilization. A study was conducted to reduce well construction and operation costs associated with in situ leach mining while increasing mineral recovery. After the borehole is c...

1984-01-01

310

In Situ Bioremediation of Perchlorate in Groundwater.  

National Technical Information Service (NTIS)

A field demonstration was conducted to evaluate the in situ treatment of perchlorate using a horizontal flow treatment well (HFTW) system to mix electron donor into perchlorate impacted groundwater. The complete demonstration results are provided in this ...

J. Diebold P. Hatzinger

2009-01-01

311

In Situ Bioremediation of Perchlorate in Groundwater.  

National Technical Information Service (NTIS)

The objectives of this project were to demonstrate the following: (1) that in situ biological perchlorate treatment is feasible in the field using electron donor addition; (2) that perchlorate can be treated to.

M. Goltz

2009-01-01

312

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

313

Accelerated in situ bioremediation of groundwater.  

National Technical Information Service (NTIS)

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...

M. J. Truex B. S. Hooker D. B. Anderson

1996-01-01

314

An In-situ Benthic Respirometer.  

National Technical Information Service (NTIS)

Preliminary field tests of an in-situ benthic respirometer yielded reasonable results which are believed to be a satisfactory measure of the benthal oxygen demands actually occurring in the waters studied. Further tests of this measurement technique under...

O'Connell Weeks

1965-01-01

315

In-situ carcinoma of the breast.  

PubMed

This article elucidates the clinical and pathological features of both ductal and lobular in-situ breast carcinoma. It quantifies the risk of invasive disease developing and outlines different treatment options with results as presently known. PMID:2175227

Phipps, R F; Rayter, Z

1990-09-01

316

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...

317

Improved radioxenon gamma-spectrometry counting system and its efficiency calibration: Monte Carlo simulation and experimental results at enriched xenon counting environment  

Microsoft Academic Search

To give satisfactory efficiency both for X- and gamma-ray photon, an improved counting system has been developed in CTBT Canadian\\u000a radioxenon laboratory. The counting system consists of a BEGe detector coupled with a thin carbon fiber window counting cell,\\u000a that can perform a reliable and efficient radioxenon measurement. A semi-empirical calibration procedure was adopted, which\\u000a is a combination of experimental

W. Zhang; K. Ungar; M. Bean

2009-01-01

318

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

319

[In situ gene amplification on tissue sections (in situ PCR). A new technique for pathologists].  

PubMed

In situ polymerase chain reaction is a recent technique which combines the sensitivity of PCR reaction to intracellular localization of genomic sequences with the same specificity as in situ hybridization. This reaction is based on the in situ annealing and polymerisation of oligonucleotides complementary to nucleotides located at each side of the target DNA sequence to amplify. We describe the Hot Start PCR (DNA) and the Hot Start PCR after reverse transcription step (RNA). It allows to amplify some nucleic sequences to a high level, becoming easier to detect. The vizualisation can be realized by direct in situ PCR, the product obtained being directly identifiable by incorporation of labeled nucleotides or primers, or preferentially by indirect in situ PCR. In this case, the amplification is followed by in situ hybridization with labeled probes. This last procedure is more specific. Numerous controls are essential at each step of the technique for validating results. PMID:8720848

Walker, F; Bedel, C; Boucher, O; Dauge, M C; Vissuzaine, C; Potet, F

1995-01-01

320

Non-destructive in-situ method and apparatus for determining radionuclide depth in media  

DOEpatents

A non-destructive method and apparatus which is based on in-situ gamma spectroscopy is used to determine the depth of radiological contamination in media such as concrete. An algorithm, Gamma Penetration Depth Unfolding Algorithm (GPDUA), uses point kernel techniques to predict the depth of contamination based on the results of uncollided peak information from the in-situ gamma spectroscopy. The invention is better, faster, safer, and/cheaper than the current practice in decontamination and decommissioning of facilities that are slow, rough and unsafe. The invention uses a priori knowledge of the contaminant source distribution. The applicable radiological contaminants of interest are any isotopes that emit two or more gamma rays per disintegration or isotopes that emit a single gamma ray but have gamma-emitting progeny in secular equilibrium with its parent (e.g., .sup.60 Co, .sup.235 U, and .sup.137 Cs to name a few). The predicted depths from the GPDUA algorithm using Monte Carlo N-Particle Transport Code (MCNP) simulations and laboratory experiments using .sup.60 Co have consistently produced predicted depths within 20% of the actual or known depth.

Xu, X. George (Clifton Park, NY); Naessens, Edward P. (West Point, NY)

2003-01-01

321

A non-destructive method to determine the depth of radionuclides in materials in-situ.  

PubMed

A non-destructive method based on in-situ gamma spectroscopy is developed to determine the depth of radiological contamination in media. An innovative algorithm, Gamma Penetration Depth Unfolding Algorithm (GPDUA), uses point kernel techniques to predict the depth of contamination based on the results of the uncollided peak information from the in-situ gamma spectroscopy. The GPDUA is designed and verified through extensive Monte Carlo simulations and validated through laboratory experiments. This innovative tool promises to be "better, faster, safer, and cheaper" than the current practice in decontamination and decommissioning. The method requires the a priori knowledge of the contaminant source distribution. The applicable radiological contaminants of interest are any isotopes that emit two or more gamma rays per disintegration or isotopes that emit a single gamma ray but have gamma-emitting progeny in secular equilibrium with its parent (e.g., 60Co, 235U, and 137Cs to name a few). The predicted depths from the GPDUA algorithm using Monte Carlo N-Particle Transport Code simulations and laboratory experiments using 60Co have consistently produced predicted depths within 20% of the actual or known depth. PMID:10376545

Naessens, E P; Xu, X G

1999-07-01

322

In situ synthesis of Peptide nucleic acids in porous silicon for drug delivery and biosensing.  

PubMed

Peptide nucleic acids (PNA) are a unique class of synthetic molecules that have a peptide backbone and can hybridize with nucleic acids. Here, a versatile method has been developed for the automated, in situ synthesis of PNA from a porous silicon (PSi) substrate for applications in gene therapy and biosensing. Nondestructive optical measurements were performed to monitor single base additions of PNA initiated from (3-aminopropyl)triethoxysilane attached to the surface of PSi films, and mass spectrometry was conducted to verify synthesis of the desired sequence. Comparison of in situ synthesis to postsynthesis surface conjugation of the full PNA molecules showed that surface mediated, in situ PNA synthesis increased loading 8-fold. For therapeutic proof-of-concept, controlled PNA release from PSi films was characterized in phosphate buffered saline, and PSi nanoparticles fabricated from PSi films containing in situ grown PNA complementary to micro-RNA (miR) 122 generated significant anti-miR activity in a Huh7 psiCHECK-miR122 cell line. The applicability of this platform for biosensing was also demonstrated using optical measurements that indicated selective hybridization of complementary DNA target molecules to PNA synthesized in situ on PSi films. These collective data confirm that we have established a novel PNA-PSi platform with broad utility in drug delivery and biosensing. PMID:24949894

Beavers, Kelsey R; Mares, Jeremy W; Swartz, Caleb M; Zhao, Yiliang; Weiss, Sharon M; Duvall, Craig L

2014-07-16

323

Comparison of inductively coupled mass spectrometry and ultra low-level gamma-ray spectroscopy for ultra low background material selection.  

PubMed

The main target of this study is the development and the validation of an internal procedure to measure the pg g(-1) levels, of naturally occurring radioisotopes to select ultra low background detector materials. As there are no ultra low-level certified reference materials commercially available, the performance of ICP-MS was compared with the well established ultra low-level gamma-spectroscopy. This work shows also the reliability of very quick ICP-MS semi-quantitative analyses of an environmental matrix such as a geological sample treated according to conventional protocols. PMID:19269836

Nisi, S; Di Vacri, A; Di Vacri, M L; Stramenga, A; Laubenstein, M

2009-05-01

324

Mineral exploration and soil analysis using in situ neutron activation  

USGS Publications Warehouse

A feasibility study has been made to operate by remote control an unshielded portable positive-ion accelerator type neutron source to induce activities in the ground or rock by "in situ" neutron irradiation. Selective activation techniques make it possible to detect some thirty or more elements by irradiating the ground for periods of a few minutes with either 3-MeV or 14-MeV neutrons. The depth of penetration of neutrons, the effect of water content of the soil on neutron moderation, gamma ray attenuation in the soil and other problems are considered. The analysis shows that, when exploring for most elements of economic interest, the reaction 2H(d,n)3He yielding ??? 3-MeV neutrons is most practical to produce a relatively uniform flux of neutrons of less than 1 keV to a depth of 19???-20???. Irradiation with high energy neutrons (??? 14 MeV) can also be used and may be better suited for certain problems. However, due to higher background and lower sensitivity for the heavy minerals, it is not a recommended neutron source for general exploration use. Preliminary experiments have been made which indicate that neutron activation in situ is feasible for a mineral exploration or qualititative soil analysis. ?? 1976.

Senftle, F. E.; Hoyte, A. F.

1966-01-01

325

Mass spectrometry.  

NASA Technical Reports Server (NTRS)

Review of the current state of mass spectrometry, indicating its unique importance for advanced scientific research. Mass spectrometry applications in computer techniques, gas chromatography, ion cyclotron resonance, molecular fragmentation and ionization, and isotope labeling are covered. Details are given on mass spectrometry applications in bio-organic chemistry and biomedical research. As the subjects of these applications are indicated alkaloids, carbohydrates, lipids, terpenes, quinones, nucleic acid components, peptides, antibiotics, and human and animal metabolisms. Particular attention is given to the mass spectra of organo-inorganic compounds, inorganic mass spectrometry, surface phenomena such as secondary ion and electron emission, and elemental and isotope analysis. Further topics include mass spectrometry in organic geochemistry, applications in geochronology and cosmochemistry, and organic mass spectrometry.

Burlingame, A. L.; Johanson, G. A.

1972-01-01

326

In Situ Forming Polymeric Drug Delivery Systems  

PubMed Central

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.

Madan, M.; Bajaj, A.; Lewis, S.; Udupa, N.; Baig, J. A.

2009-01-01

327

Calculated trends and the atmospheric abundance of 1,1,1,2-tetrafluoroethane, 1,1-dichloro-1-fluoroethane, and 1-chloro-1,1-difluoroethane using automated in-situ gas chromatography-mass spectrometry measurements recorded at Mace Head, Ireland, from October 1994 to March 1997  

Microsoft Academic Search

The first in-situ measurements by automated gas chromatograph-mass spectrometer are reported for 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1-dichloro-1-fluoroethane, (HCFC-141b), and 1-chloro-1,1-difluoroethane, (HCFC-142b). These compounds are steadily replacing the chlorofluorocarbons (CFCs) as refrigerants, foam-blowing agents, and solvents. The concentrations of all three compounds are shown to be rapidly increasing in the atmosphere, with 134a increasing at a rate of 2.05+\\/-0.02pptyr-1 over the 30 months

P. G. Simmonds; S. O'Doherty; J. Huang; R. Prinn; R. G. Derwent; D. Ryall; G. Nickless; D. Cunnold

1998-01-01

328

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 ...

329

Current management of ductal carcinoma in situ.  

PubMed Central

Ductal carcinoma in situ represents a biologically and histologically heterogeneous group of lesions characterized by the proliferation of neoplastic epithelial cells confined to the ducts of the breast. Before screening mammography, ductal carcinoma in situ was considered uncommon; patients were usually diagnosed by a breast mass or bloody nipple discharge, and their treatment was mastectomy. Today it represents 20% to 30% of mammographically detected breast cancers and 10% to 15% of all diagnosed breast cancers in the United States. The invariable progression of this cancer to invasive breast cancer requiring mastectomy has been challenged, but because most patients have been treated with mastectomy, knowledge about ductal carcinoma in situ is limited and primarily based on retrospective data. Further insight will emerge from randomized prospective studies that are near completion. Currently available data indicate that breast-conserving treatments are valid alternatives to mastectomy for most patients with this disease. Images Figure 1.

Barth, A; Brenner, R J; Giuliano, A E

1995-01-01

330

Colonic in situ mantle cell lymphoma.  

PubMed

This report describes the first case, to our knowledge, of in situ mantle cell lymphoma (MCL) in the gastrointestinal tract identified retrospectively by immunostains and fluorescence in situ hybridization (FISH) analysis after progression to disseminated disease with pleomorphic morphology several years later. A 45-year-old man with blood per rectum underwent colonoscopy and had random biopsies interpreted as benign colonic mucosa. Two years later, he presented with ileocolic intussusception related to enlarged lymph nodes. Biopsies on the second presentation demonstrated widespread MCL. Reevaluation of the original colonic biopsies showed cyclin D1-positive cells within small lymphoid aggregates, confirmed by FISH for t(11;14). Postchemotherapy, lymphoid aggregates in colonic biopsies showed scattered cyclin D1- and FISH t(11;14)-positive cells, similar to the original in situ lymphoma. We discuss this case in the context of the current understanding of the evolution of MCL and the difficulties associated with detecting primary GI lymphoma. PMID:21840231

Neto, Antonio G; Oroszi, Gabor; Protiva, Petr; Rose, Michal; Shafi, Nelofar; Torres, Richard

2012-12-01

331

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

2013-04-01

332

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. 7 figs.

Powell, J.R.; Reich, M.; Barletta, R.

1997-10-14

333

Current management of lobular in situ neoplasia.  

PubMed

Although the term of lobular neoplasia was first proposed in 1978 and the term Lobular In situ Neoplasia (LIN) has been incorporated in the current World Health Organisation (WHO) classification to cover both atypical lobular hyperplasia (ALH) and lobular carcinoma in situ (LCIS), the clinical significance and the natural history of lobular neoplasia is far from being fully understood. Furthermore problems and confusion still remain surrounding (1) the most appropriate terminology and classification for these lesions, (2) the best course of long-term management after diagnosis.This article summarizes the opinions on LCIS management of a group of Belgian experts. PMID:18817092

Liebens, F; Cardinael, A S; Schillings, A P; Mendez, V; Demoulin, C; Cusumano, P; Carly, B; Faverly, D; Rozenberg, S

2008-01-01

334

In-situ observation of ettringite crystals  

NASA Astrophysics Data System (ADS)

In-situ observation of growing ettringite crystals in solution has been carried out and the morphology change of ettringite has been investigated under various conditions. In particular, the acceleration behavior of ettringite growth in the presence of calcite, the cause of which is not yet understood, is examined. Spherulite with calcite in its core is formed first followed by the generation of acicular crystals. Compared with the in-situ observation result of crystal growth in a solution with no calcite, the effect of added calcite can be explained as a decrease in the activation energy of nucleation for ettringite around calcite.

Komatsu, Ryuichi; Mizukoshi, Norihiro; Makida, Koji; Tsukamoto, Katsuo

2009-01-01

335

Identification of differentially expressed proteins of gamma-ray irradiated rat intestinal epithelial IEC-6 cells by two-dimensional gel electrophoresis and matrix-assisted laser desorption/ionisation-time of flight mass spectrometry.  

PubMed

To identify proteins involved in the processes of cellular and molecular response to radiation damage repair in intestinal epithelial IEC-6 cells, we comparatively analyzed the proteome of irradiated IEC-6 cells with that of normal cells. A series of methods were used, including two-dimensional gel electrophoresis (Z-DE), PDQuest software analysis of 2-DE gels, peptide mass fingerprinting based on matrix-assisted laser desorption/ionisation-time of flight-mass spectrometry (MALDI-TOF-MS), and Swiss-Prot database searching, to separate and identify differentially expressed proteins. Western blotting and reverse transcriptase polymerase chain reaction (RT-PCR) were used to validate the differentially expressed proteins. Image analysis revealed that averages of 608 +/- 39 and 595 +/- 31 protein spots were detected in normal and irradiated IEC-6 cells, respectively. Sixteen differential protein spots were isolated from gels, and measured with MALDI-TOF-MS. A total of 14 spots yielded good spectra, and 11 spots matched with known proteins after database searching. These proteins were mainly involved in anti-oxidation, metabolism, and protein post-translational processes. Western blotting confirmed that stress-70 protein was down-regulated by gamma-irradiation. Up-regulation of ERP29 was confirmed by RT-PCR, indicating that it is involved in ionizing radiation. The clues provided by the comparative proteome strategy utilized here will shed light on molecular mechanisms of radiation damage repair in intestinal epithelial cells. PMID:15700242

Bo, Zhang; Yongping, Su; Fengchao, Wang; Guoping, Ai; Yongjiang, Wei

2005-02-01

336

SENSITIVITY STUDIES FOR AN IN-SITU PARTIAL DEFECT DETECTOR (PDET) IN SPENT FUEL USING MONTE CARLO TECHNIQUES  

Microsoft Academic Search

This study presents results from Monte Carlo radiation transport calculations aimed at characterizing a novel methodology being developed to detect partial defects in Pressurized Water Reactor (PWR) spent fuel assemblies (SFAs). The methodology uses a combination of measured neutron and gamma fields inside a spent fuel assembly in an in-situ condition where no movement of the fuel assembly is required.

S Sitaraman; Y S Ham

2008-01-01

337

Determination of gamma-hydroxybutyric acid in biofluids using a one-step procedure with "in-vial" derivatization and headspace-trap gas chromatography-mass spectrometry.  

PubMed

A headspace-trap gas chromatography-mass spectrometry (HS-trap GC-MS) method was developed to determine GHB, a low molecular weight compound and drug of abuse, in various biological fluids. Combining this relatively novel and fully automated headspace technique with "in-vial" methylation of GHB allowed for a straightforward approach. One single method could be used for all biofluids (urine, plasma, serum, whole blood or lyzed blood), requiring only 100?l of sample. Moreover, our approach involves mere addition of all reagents and sample into one vial. Following optimization of headspace conditions and trap settings, validation was performed. Although sample preparation only consists of the addition of salt and derivatization reagents directly to a 100?l-sample in a HS-vial, adequate method sensitivity and selectivity was obtained. Calibration curves ranged from 5 to 150?g/ml GHB for urine, from 2 to 150?g/ml for plasma, and from 3.5 to 200?g/ml for whole blood. Acceptable precision and accuracy (<13% bias and imprecision) were seen for all quality controls (QC's) (LLOQ-level, low, medium, high), including for the supplementary serum- and lyzed blood-based QC's, using calibration curves prepared in plasma or whole blood, respectively. Incurred sample reanalysis demonstrated assay reproducibility, while cross-validation with another GC-MS method demonstrated that our method is a valuable alternative for GHB determination in toxicological samples, with the advantage of requiring only 100?l and minimal hands-on time, as sample preparation is easy and injection automated. PMID:23664352

Ingels, Ann-Sofie M E; Neels, Hugo; Lambert, Willy E; Stove, Christophe P

2013-06-28

338

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

339

Scintillation modeling using in situ data  

Microsoft Academic Search

Satellite in situ measurements of plasma (electron) density fluctuations provide direct information about the structure and morphology of irregularities that are responsible for scintillation of radio waves on transionospheric links. When supplemented with the ionosphere model and irregularity anisotropy model, they can be applied to model morphology of scintillation provided a suitable propagation model is used. In this paper we

A. W. Wernik; L. Alfonsi; M. Materassi

2007-01-01

340

"In Situ" Generation of Compressed Inverted Files.  

ERIC Educational Resources Information Center

Discussion of index construction for large text collections highlights a new indexing algorithm designed to create large compressed inverted indexes "in situ." Topics include a computational model, inversion, index compression, merging, experimental test results, effect on retrieval performance, memory restrictions, and dynamic collections.…

Moffat, Alistair; Bell, Timothy A. H.

1995-01-01

341

Characterizing In Situ Uranium and Groundwater Flux  

Microsoft Academic Search

The goal of this project is to develop a new sensor that incorporates the field-tested concepts of the passive flux meter to provide direct in situ measures of uranium and groundwater fluxes. The sensor uses two sorbents and resident tracers to measure uranium flux and specific discharge directly; but, sensor principles and design should also apply to fluxes of other

J. Cho; M. A. Newman; V. Stucker; A. Peacock; J. Ranville; S. Cabaniss; K. Hatfield; M. D. Annable; H. Klammler; I. V. Perminova

2010-01-01

342

In situ recovery of shale oil  

Microsoft Academic Search

An in situ oil shale retort is formed in a subterranean oil shale deposit by excavating a columnar void having a vertically extending free face, drilling blasting holes adjacent to the columnar void and parallel to the free face, loading the blasting holes with explosive, and detonating the explosive in a single round to expand the shale adjacent to the

1977-01-01

343

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...

344

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

345

Projectile penetration of in situ rock  

Microsoft Academic Search

Ninteen tests of air-delivered, large projectiles (8 to 10 in. dia, 500 ; to 1000 lb) penetrating in situ rock are reported. The rock targets are ; classified in terms of the strength of an intact sample and the physical ; discontinuities in the formations. An instrumentation system was developed for ; rigid-body deceleration-versus-time data during rock penetration. Although soil

1973-01-01

346

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...

347

In Situ Test for Soil Creep.  

National Technical Information Service (NTIS)

The Iowa bore-hole shear apparatus, modified to monitor time deformational behavior in soils, produced both primary and tertiary type creep curves from in-situ tests on soils. Laboratory simple shear tests produced comparable results. An examination of th...

R. A. Lohnes A. Millan T. Demirel R. L. Handy

1971-01-01

348

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

349

In situ Combustion of Coal for Energy.  

National Technical Information Service (NTIS)

A concept of efficient thermal energy generation through the in situ combustion of coal, and the on-site conversion of that energy to electricity is discussed and shown to offer distinct advantages in the utilization of our coal reserves. Analysis of data...

R. F. Chaiken

1974-01-01

350

Fabrication Capabilities Utilizing In Situ Materials  

NASA Technical Reports Server (NTRS)

The National Aeronautics and Space Administration (NASA) has a Space Exploration Policy that lays out a plan that far exceeds the earlier Apollo goals where landing on the moon and taking those first historic steps fulfilled the mission. The policy states that we will set roots on the moon by establishing an outpost. This outpost will be used as a test bed for residing in more distant locales, such as Mars. In order to become self-sufficient, the occupants must have the capability to fabricate component parts in situ. Additionally, in situ materials must be used to minimize valuable mission upmass and to be as efficient as possible. In situ materials can be found from various sources such as raw lunar regolith whereby specific constituents can be extracted from the regolith (such as aluminum, titanium, or iron), and existing hardware already residing on the moon from past Apollo missions. The Electron Beam Melting (EBM) process lends itself well to fabricating parts, tools, and other necessary items using in situ materials and will be discussed further in this paper.

McLemore, Carole A.; Fikes, John C.; Darby, Charles A.; Good, James E.; Gilley, Scott D.

2008-01-01

351

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...

352

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...

353

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...

354

In Situ Vitrification software requirements specification  

SciTech Connect

This report describes the Software Requirements Specification for the Electrical Resistance Heating and Thermal Energy Transport models of the In-Situ Vitrification (ISV) process. It contains the Data Flow Diagrams, Process Specifications, Data Structure Diagrams, and the Data Dictionary. 5 refs.

Grush, W.H.; Marwil, E.S.

1990-09-01

355

Mars in Situ Resource Utilization Technology Evaluation.  

National Technical Information Service (NTIS)

We have examined the technologies required to enable Mars In-Situ Resource Utilization (ISRU) because our understanding of Mars resources has changed significantly in the last five years as a result of recent robotic missions to the red planet. Two major ...

A. C. Muscatello E. Santago-Maldonado

2012-01-01

356

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

357

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...

358

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...

359

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

360

Parametric melting studies for in situ vitrification  

SciTech Connect

This report describes a series of simulation studies which examine heat conduction and electric heating during in situ vitrification (ISV). The simulation studies determine the effects of soil parameter changes on the ISV process. Changes in heat capacity, thermal conductivity and electrical conductivity are considered. The results of these studies provide a basis for experimental measurement accuracy requirements.

Fryer, M.O.; Hawkes, G.L.; Murray, P.E.

1991-11-01

361

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

362

Spatial distribution of gamma radiation levels in surface soils from Jaduguda uranium mineralization zone, Jharkhand, India, using ?-ray spectrometry, and determination of outdoor dose to the population.  

PubMed

The concentrations of natural radionuclides in surface soil samples around selected villages of Jaduguda were investigated and compared with the radioactivity level in the region. Concentrations of (238)U, (232)Th, and (40)K were determined by a gamma ray spectrometer using the HPGe detector with 50% relative efficiency, and the radiation dose to the local population was estimated. The average estimated activity concentrations of (238)U, (232)Th, and (40)K in the surface soil were 53.8, 44.2 and 464.2 Bq kg(-1) respectively. The average absorbed dose rate in the study area was estimated to be 72.5 nGy h-1, where as the annual effective dose to the population was 0.09 mSv y-1. A correlation analysis was made between measured dose rate and individual radionuclides, in order to delineate the contribution of the respective nuclides towards dose rate. The radio-elemental concentrations of uranium, thorium and potassium estimated for the soils, in the study area, indicated the enrichment of uranium series nuclide. The results of the present study were subsequently compared with international and national recommended values. PMID:21170189

Maharana, Mandakini; Krishnan, Narayani; Sengupta, D

2010-10-01

363

Spatial distribution of gamma radiation levels in surface soils from Jaduguda uranium mineralization zone, Jharkhand, India, using ?-ray spectrometry, and determination of outdoor dose to the population  

PubMed Central

The concentrations of natural radionuclides in surface soil samples around selected villages of Jaduguda were investigated and compared with the radioactivity level in the region. Concentrations of 238U, 232Th, and 40K were determined by a gamma ray spectrometer using the HPGe detector with 50% relative efficiency, and the radiation dose to the local population was estimated. The average estimated activity concentrations of 238U, 232Th, and 40K in the surface soil were 53.8, 44.2 and 464.2 Bq kg?1 respectively. The average absorbed dose rate in the study area was estimated to be 72.5 nGy h-1, where as the annual effective dose to the population was 0.09 mSv y-1. A correlation analysis was made between measured dose rate and individual radionuclides, in order to delineate the contribution of the respective nuclides towards dose rate. The radio-elemental concentrations of uranium, thorium and potassium estimated for the soils, in the study area, indicated the enrichment of uranium series nuclide. The results of the present study were subsequently compared with international and national recommended values.

Maharana, Mandakini; Krishnan, Narayani; Sengupta, D.

2010-01-01

364

A mass spectrometry primer for mass spectrometry imaging  

PubMed Central

Mass spectrometry imaging (MSI), a rapidly growing subfield of chemical imaging, employs mass spectrometry (MS) technologies to create single- and multi-dimensional localization maps for a variety of atoms and molecules. Complimentary to other imaging approaches, MSI provides high chemical specificity and broad analyte coverage. This powerful analytical toolset is capable of measuring the distribution of many classes of inorganics, metabolites, proteins and pharmaceuticals in chemically and structurally complex biological specimens in vivo, in vitro, and in situ. The MSI approaches highlighted in this Methods in Molecular Biology volume provide flexibility of detection, characterization, and identification of multiple known and unknown analytes. The goal of this chapter is to introduce investigators who may be unfamiliar with MS to the basic principles of the mass spectrometric approaches as used in MSI. In addition to guidelines for choosing the most suitable MSI method for specific investigations, cross-references are provided to the chapters in this volume that describe the appropriate experimental protocols.

Rubakhin, Stanislav S.; Sweedler, Jonathan V.

2011-01-01

365

In Situ Remediation Integrated Program: Technology summary  

SciTech Connect

The In Situ Remediation Integrated Program (ISR IP) was instituted out of recognition that in situ remediation could fulfill three important criteria: significant cost reduction of cleanup by eliminating or minimizing excavation, transportation, and disposal of wastes; reduced health impacts on workers and the public by minimizing exposure to wastes during excavation and processing; and remediation of inaccessible sites, including: deep subsurfaces, in, under, and around buildings. Buried waste, contaminated soils and groundwater, and containerized wastes are all candidates for in situ remediation. Contaminants include radioactive wastes, volatile and non-volatile organics, heavy metals, nitrates, and explosive materials. The ISR IP intends to facilitate development of in situ remediation technologies for hazardous, radioactive, and mixed wastes in soils, groundwater, and storage tanks. Near-term focus is on containment of the wastes, with treatment receiving greater effort in future years. ISR IP is an applied research and development program broadly addressing known DOE environmental restoration needs. Analysis of a sample of 334 representative sites by the Office of Environmental Restoration has shown how many sites are amenable to in situ remediation: containment--243 sites; manipulation--244 sites; bioremediation--154 sites; and physical/chemical methods--236 sites. This needs assessment is focused on near-term restoration problems (FY93--FY99). Many other remediations will be required in the next century. The major focus of the ISR EP is on the long term development of permanent solutions to these problems. Current needs for interim actions to protect human health and the environment are also being addressed.

Not Available

1994-02-01

366

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

367

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

368

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

369

The Orléans-Lithothèque - an analogue rockstore for in situ missions  

NASA Astrophysics Data System (ADS)

The Orléans-Lithothèque - an analogue rockstore for in situ missions Nicolas Bost, Frances Westall, Claire Ramboz, Axelle Hubert, Derek Pullan, Beda Hofmann, Elisabeth Vergès, Michel Viso, Jorge Vago, Christelle Briois, Bruno Scaillet, Michel Tagger Instruments for in-situ missions to extraterrestrial bodies should ideally be cross calibrated using a common suite of relevant materials. Such multi-instrument calibration would enable a better comparison of instrument performances during the mission, as well as aid in the interpretation of the in-situ measurements. At the CNRS in Orléans, the Observatoire des Sciences de l'Univers de la region Centre is creating a collection of well-characterised rocks that will be available for testing and calibrating instruments to be flown on space missions. The characteristics of the collection's analogue materials will be described in an online database. In view of the upcoming 2018 ExoMars rover mission, we are concentrating initially on materials of direct relevance to Mars. The initial collection includes basalts (ultramafic, weathered, andesitic, hydrothermally-silicified); sediments (volcanic, biolaminated, banded iron formation); and minerals (silica, evaporites, clays, Fe oxides). This set of samples will be augmented with time. All samples will be characterised petrographically, petrologically, and geochemically using the types of analyses likely to be performed during an in-situ mission: hand specimen description, optical microscopy, mineralogical analysis (XRD, Raman and IR spectrometry), elemental analysis (EDX, microprobe, ICP) and organics analysis (Raman, pyr-GCMS).

Bost, Nicolas; Westall, Frances; Ramboz, Claire

2010-05-01

370

Imaging Mass Spectrometry in Neuroscience  

PubMed Central

Imaging mass spectrometry is an emerging technique of great potential for investigating the chemical architecture in biological matrices. Although the potential for studying neurobiological systems is evident, the relevance of the technique for application in neuroscience is still in its infancy. In the present Review, a principal overview of the different approaches, including matrix assisted laser desorption ionization and secondary ion mass spectrometry, is provided with particular focus on their strengths and limitations for studying different neurochemical species in situ and in vitro. The potential of the various approaches is discussed based on both fundamental and biomedical neuroscience research. This Review aims to serve as a general guide to familiarize the neuroscience community and other biomedical researchers with the technique, highlighting its great potential and suitability for comprehensive and specific chemical imaging.

2013-01-01

371

In situ soil remediation using electrokinetics  

SciTech Connect

Electrokinetics is emerging as a promising technology for in situ soil remediation. This technique is especially attractive for Superfund sites and government operations which contain large volumes of contaminated soil. The approach uses an applied electric field to induce transport of both radioactive and hazardous waste ions in soil. The transport mechanisms include electroosmosis, electromigration, and electrophoresis. The feasibility of using electrokinetics to move radioactive {sup 137}Cs and {sup 60}Co at the Hanford Site in Richland, Washington, is discussed. A closed cell is used to provide in situ measurements of {sup 137}Cs and {sup 60}Co movement in Hanford soil. Preliminary results of ionic movement, along with the corresponding current response, are presented.

Buehler, M.F.; Surma, J.E.; Virden, J.W.

1994-11-01

372

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

373

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

374

In situ bioremediation of chlorinated solvents.  

PubMed Central

Chlorinated solvents and their natural transformation products are the most frequently observed groundwater contaminants in the United States. In situ bioremediation using anaerobic or aerobic co-metabolic processes is a promising means of cleaning up contaminated aquifers. Studies show that under natural conditions trichloroethylene can be anaerobically degraded to dichloroethylene, vinyl chloride, and ethylene. Pilot scale field studies of in situ aerobic co-metabolic transformations have shown that indigenous microbes grown on phenol are more effective at degrading trichloroethylene and cis-1,2-dichloroethylene than microbes grown on methane. Modeling studies support field observations and indicate that the removal of trichloroethylene and cis-dichloroethylene results from the biostimulation of an indigenous microbial population. Field tests and modeling studies indicate that, at high TCE concentration, degradation becomes stoichiometrically limited.

Semprini, L

1995-01-01

375

Photocrosslinkable polysaccharides for in situ hydrogel formation.  

PubMed

In situ photopolymerization is an exciting new technique for tissue engineering. Two photocrosslinkable polysaccharides composed of alginate and hyaluronan are described that upon photolysis form soft, flexible, and viscoelastic hydrogels. The degree of methacrylate modification and thus covalent affects mechanical properties such as swelling, compression, and creep compliance. Significant swelling is observed in aqueous solution; these hydrogels can swell up to 14 times their dry weight. Both hydrogels exhibit low phase angles and (G*) values indicative of viscoelastic materials. The hyaluronan based hydrogel is stronger and more resilient than the corresponding alginate gel. SEM and AFM studies on both hydrogels show smooth and uniform surfaces at the macroscopic level with salient features observed only on the nanometer scale. Rapid polymerization by an optical trigger allows for controlled in situ photopolymerization in a minimally invasive manner, indicating that these hydrogels are relevant for biomedical applications such as sealing wounds and reconstructing soft tissues. PMID:11077410

Smeds, K A; Pfister-Serres, A; Miki, D; Dastgheib, K; Inoue, M; Hatchell, D L; Grinstaff, M W

2001-01-01

376

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

377

Breast: Ductal Carcinoma In Situ (DCIS)  

Microsoft Academic Search

\\u000a Ductal carcinoma in situ (DCIS) of the breast is a proliferation of malignant epithelial cells within parenchymal structures\\u000a of the breast, which is distinguished from invasive carcinoma by the absence of stromal invasion through the limiting basement\\u000a membrane. Although the incidence of DCIS has apparently increased over the last 20 years, this is interpreted as a result\\u000a of the enhanced

John P. Brown; Sarah E. Pinder

378

Femtosecond laser in laser in situ keratomileusis  

PubMed Central

Flap creation is a critical step in laser in situ keratomileusis (LASIK). Efforts to improve the safety and predictability of the lamellar incision have fostered the development of femtosecond lasers. Several advantages of the femtosecond laser over mechanical microkeratomes have been reported in LASIK surgery. In this article, we review common considerations in management and complications of this step in femtosecond laser–LASIK and concentrate primarily on the IntraLase laser because most published studies relate to this instrument.

Salomao, Marcella Q.; Wilson, Steven E.

2014-01-01

379

Ductal carcinoma in situ: a challenging disease  

Microsoft Academic Search

Ductal carcinoma in situ (DCIS) represents a heterogenous group of lesions with variable malignant potential. Although it\\u000a is clearly pre-invasive, not all lesions progress to an invasive malignant disease. The significant increase in the frequency\\u000a of diagnosis is the result of both widespread use of screening mammography and better recognition among pathologists. Treatment\\u000a is controversial, but for several decades total

Sevilay Altintas; Manon T. Huizing; Eric Van Marck; Jan B. Vermorken; Wiebren A. Tjalma

2010-01-01

380

LONG TERM IN SITU DISPOSAL ENGINEERING STUDY  

Microsoft Academic Search

Patent application pulled per Ken Norris (FH General Counsel). The objective of this study is to devise methods, produce conceptual designs, examine and select alternatives, and estimate costs for the demonstration of long-term (300-year) in situ disposal of an existing waste disposal site. The demonstration site selected is the 216-A-24 Crib near the 200 East Area. The site contains a

2003-01-01

381

In situ health monitoring of piezoelectric sensors  

NASA Technical Reports Server (NTRS)

An in situ health monitoring apparatus may include an exciter circuit that applies a pulse to a piezoelectric transducer and a data processing system that determines the piezoelectric transducer's dynamic response to the first pulse. The dynamic response can be used to evaluate the operating range, health, and as-mounted resonance frequency of the transducer, as well as the strength of a coupling between the transducer and a structure and the health of the structure.

Jensen, Scott L. (Inventor); Drouant, George J. (Inventor)

2013-01-01

382

In situ lead immobilization by apatite  

Microsoft Academic Search

Lead contamination is of environmental concern due to its effect on human health. The purpose of this study was to develop a technology to immobilize Pb in situ in contaminated soils and wastes using apatite. Hydroxy- apatite (Calo(P04)6(OH)2) was reacted with aqueous Pb, resin-exchangeable Pb, and Pb-contaminated soil material. The effectiveness of natural apatite to attenuate Pb was also tested.

Qi Ying Ma; Samuel J. Traina; Terry J. Logan; James A. Ryan

1993-01-01

383

Choriocarcinoma in situ at a first trimester  

Microsoft Academic Search

Two cases of choriocarcinoma in situ arising in a first trimester placenta are reported in a 28-year-old gravida 2, para 1, Japanese woman and a 38-year-old gravida 2, para 0. Both had a dilation and curettage (D and C) for vaginal bleeding and the absence of intrauterine fetus. No macroscopic abnormalities were noted in either case. However, histologically, localized nodules

M. Fukunaga; K. Nomura; S. Ushigome

1996-01-01

384

Pathology of the human mesangium in situ  

Microsoft Academic Search

Mesangial cells play an important role in the development and progression of human glomerular disease. This article summarizes some important aspects of mesangial properties and behaviour in situ. Intrinsic mesangial cells express a-smooth muscle actin and are best characterized as myofibroblasts or glomerular pericytes. The main intergin receptor in the mesangium is the a1\\\\1 integrin. The \\\\2 and \\\\3 integrins

R. Waldherr; S. Cuzic; I. L. Noronha

1992-01-01

385

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

386

Overview of the current definition of Ductal Carcinoma in Situ  

Cancer.gov

Ductal Carinoma in Situ: Strategies for Integrating Tumor Biology and Population Sciences February 1-2, 2007, San Francisco, CA Overview of the current definition of Ductal Carcinoma in Situ Donald L. Weaver, MD University of Vermont In the beginning… •

387

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...

388

In situ remediation: Developing containment technologies  

SciTech Connect

The In Situ Remediation Integrated Program (ISR IP) was established by the US Department of Energy`s (DOE) Office of Technology Development (OTD) to advance the state-of-the art of innovative in situ remediation technologies to the point of demonstration, and to broaden the applicability of these technologies to the widely varying site remediation requirements throughout the DOE complex. This program complements ongoing demonstration programs being conducted at several DOE sites. The ISR-IP has been conducting baseline assessments of in situ technologies to support program planning. One of the assessments has focused on evaluating subsurface containment barrier technologies to identify the current state-of-the-art and determine R and D requirements to enable the deployment of these technologies. DOE`s needs are mostly driven by issues concerning the large number of sites requiring remediation, the wide variation among the sites themselves, and the broad range of contaminants at these sites. Many of the sites contain a mixture of organic and inorganic hazardous waste and radioactive waste in a variety of media. Current remedial action strategies for hazardous waste sites are considering containment mostly as an interim action to prevent migration of contaminants from the site until a Record of Decision is made. In some cases, containment is also considered as a remedial action alternative where it is determined to be the best compromise between cost and effectiveness over a relatively short period of time (about 30 years).

Peterson, M.

1994-08-01

389

Practical application of in situ aerosol measurement  

SciTech Connect

The use of in situ, real-time measurement techniques permits the characterization of airborne droplets and particles under conditions where traditional sampling methods can fail. For example, sampling method rely on the ability to sample and transport particles without biasing the properties of interest, and often are not applicable in harsh environment. Although in situ methods offer unique opportunities in these cases, these techniques introduce new concerns and must be used carefully if accurate measurement are to be made. Several in situ measurement techniques are reviewed here. As the field is rapidly evolving, the discussion is limited to those techniques which: (1) are commercially available, (2) provide real-time output, (3) measure the aerosol size distribution. Discussion is divided between single particle counters (which provide a flux-based or temporal measurement) and ensemble techniques (which provide a concentration-based or spatial measurement). Specific techniques discussed include phase Doppler, Mie scattering, and Fraunhofer diffraction, and commercial instruments based on these techniques.

O`Hern, T.J.; Rader, D.J.

1993-09-01

390

Calculated trends and the atmospheric abundance of 1,1,1,2-tetrafluoroethane, 1,1-dichloro-1-fluoroethane, and 1-chloro-1,1-difluoroethane using automated in-situ gas chromatography-mass spectrometry measurements recorded at Mace Head, Ireland, from October 1994 to March 1997  

NASA Astrophysics Data System (ADS)

The first in-situ measurements by automated gas chromatograph-mass spectrometer are reported for 1,1,1,2-tetrafluoroethane (HFC-134a), 1,1-dichloro-1-fluoroethane, (HCFC-141b), and 1-chloro-1,1-difluoroethane, (HCFC-142b). These compounds are steadily replacing the chlorofluorocarbons (CFCs) as refrigerants, foam-blowing agents, and solvents. The concentrations of all three compounds are shown to be rapidly increasing in the atmosphere, with 134a increasing at a rate of 2.05±0.02 ppt yr-1 over the 30 months of observations. Similarly, 141b and 142b increased at rates of 2.49±0.03 and 1.24±0.02 ppt yr-1, respectively, over the same period. The concentrations recorded at the atmospheric research station at Mace Head, Ireland, on January 1, 1996, the midpoint of the time series, were 3.67 ppt (134a), 7.38 ppt (141b), and 8.78 ppt (142b). From these observations we optimally estimate the HCFC and HFC emissions using a 12-box global model and OH concentrations derived from global 1,1,1-trichloroethane (CCl3CH3) measurements. Comparing two methods of estimating emissions with independent industry estimates shows satisfactory agreement for 134a and 141b, while for 142b, industry estimates are less than half those required to explain our observations.

Simmonds, P. G.; O'Doherty, S.; Huang, J.; Prinn, R.; Derwent, R. G.; Ryall, D.; Nickless, G.; Cunnold, D.

1998-01-01

391

Development of Spectroelectrochemical Cells for in situ Neutron Reflectometry  

NASA Astrophysics Data System (ADS)

A new spectroelectrochemical cell for in situ neutron reflectometry was developed. Electrochemical reactions were determined using this in situ cell with a LiMn2O4/SrRuO3 multi layer thin film. Changes in interfacial structures on the surface of the thin film are also observed by in situ neutron reflectivity measurements. The performances of this in situ cell were expected the determination of changes on the interface between the electrodes and electrolytes.

Yonemura, M.; Hirayama, M.; Suzuki, K.; Kanno, R.; Torikai, N.; Yamada, N. L.

2014-04-01

392

In-situ droplet monitoring for self-tuning spectrometers  

DOEpatents

A laser scattering based imaging technique is utilized in order to visualize the aerosol droplets in an inductively coupled plasma (ICP) torch from an aerosol source to the site of analytical measurements. The resulting snapshots provide key information about the spatial distribution of the aerosol introduced by direct and indirect injection devices: 1) a direct injection high efficiency nebulizer (DIHEN); 2) a large-bore DIHEN (LB-DIHEN); and 3) a PFA microflow nebulizer with a PFA Scott-type spray chamber. Moreover, particle image velocimetry (PIV) is used to study the in-situ behavior of the aerosol before interaction with, for example, plasma, while the individual surviving droplets are explored by particle tracking velocimetry (PTV). Further, the velocity distribution of the surviving droplets demonstrates the importance of the initial droplet velocities in complete desolvation of the aerosol for optimum analytical performance in ICP spectrometries. These new observations are important in the design of the next-generation direct injection devices for lower sample consumption, higher sensitivity, lower noise levels, suppressed matrix effects, and for developing smart spectrometers. For example, a controller can be provided to control the output of the aerosol source by controlling the configuration of the source or the gas flow rate via feedback information concerning the aerosol.

Montaser, Akbar (Potomac, MD); Jorabchi, Kaveh (Arlington, VA); Kahen, Kaveh (Kleinburg, CA)

2010-09-28

393

In Situ Desorption Electrospray Ionization (DESI) Analysis of Tissue Sections.  

PubMed

INTRODUCTIONDesorption electrospray ionization (DESI) allows in situ analysis of biological tissues. The analysis of less abundant protein constituents within a tissue sample often requires the removal of lipid species prior to analysis, similar to the situation with matrix-assisted laser desorption/ionization (MALDI). After removal of lipid constituents, the tissue can be treated with protease to degrade proteins present in the tissue. The tryptic products can be investigated directly from the tissue using DESI. The spectra obtained feature ions of tryptic fragments from abundant proteins present in the tissue sample. The digestion is usually not complete; hence, the presence of missed cleavage sites is typical in the peptides detected. The signal is more stable for longer times than in the case of deposited samples, so the recording of mass spectrometry (MS)/MS data is simple in this case. DESI-MS is an emerging technique with great promise, but its application range is still being investigated. Therefore, the protocol for DESI-MS analysis of tissue sections presented here provides general procedures used for the applications that have been investigated so far. Optimal ion source parameters and surface types may vary depending on the application. PMID:21356812

Takats, Zoltan; Wiseman, Justin M; Ifa, Demian R; Cooks, R Graham

2008-01-01

394

The treatment of in situ breast cancer.  

PubMed

Carcinoma in situ is the earliest histologically recognisable form of malignancy and as such provides an opportunity to treat the disease in a curative way. However, due to the comparative rarity of in situ breast carcinoma, there is no available information derived from controlled clinical trials. The two major variants, ductal carcinoma in situ (DCIS) and lobular carcinoma in situ (LCIS) will be considered separately as the two conditions have divergent natural histories. DCIS is increasing in incidence since microcalcification, which is a frequent accompaniment, may be detected radiologically in the screening of asymptomatic women. The extent of microcalcification may not indicate the extent of disease. It has yet to be determined whether there is a difference in behaviour of the tumour forming and the asymptomatic types of DCIS. After a biopsy has shown DCIS there will be residual DCIS at the biopsy site in one-third of patients, and multifocal DCIS in another third. A coexistent infiltrating carcinoma may be present in up to 16%. Due to sampling problems areas of invasion may be missed. Axillary nodal metastases are found in only 1% of patients with histological DCIS. Radical surgery by total or modified mastectomy is almost curative, but 3% of patients will die of metastases. Taking results of uncontrolled trials, local relapse rates are as follows: excision alone 50%, wide excision 30%, wide excision plus radiotherapy 20%. Two prospective trials are underway run by the EORTC and NSABP in which patients with DCIS are treated by wide excision with or without external radiotherapy. LCIS is usually an incidental finding with a bilateral predisposition to subsequent infiltrating carcinomas. Curative procedures such as bilateral mastectomy with reconstruction may represent overtreatment. A systemic rather than local approach would seem appropriate and a trial is now underway run by the EORTC in which patients with histologically confirmed LCIS are randomised to observation alone or to receive tamoxifen 20 mg daily for 5 years. Cooperative studies will provide the way of acquiring important data on treatment regimens of both DCIS and LCIS. It is timely that treatment regimens for in situ carcinoma of the breast be examined by controlled clinical trials. PMID:2558695

Fentiman, I S

1989-01-01

395

Environmental assessment of in situ mining. Open file report (final)  

Microsoft Academic Search

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 techniques and minerals investigated. The potential impacts onsite in the desert southwest (porphyry copper), Michigan (native copper), Texas and Wyoming (uranium), and

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

1979-01-01

396

An overview of in situ waste treatment technologies  

Microsoft Academic Search

In situ technologies are becoming an attractive remedial alternative for eliminating environmental problems. In situ treatments typically reduce risks and costs associated with retrieving, packaging, and storing or disposing-waste and are generally preferred over ex situ treatments. Each in situ technology has specific applications, and, in order to provide the most economical and practical solution to a waste problem, these

S. Walker; R. A. Hyde; R. B. Piper; M. W. Roy

1992-01-01

397

In situ measurement of osmium concentrations in iron meteorites by resonance ionization of sputtered atoms  

NASA Astrophysics Data System (ADS)

Resonance ionization of sputtered atoms followed by time-of-flight mass spectrometry was used for in situ quantitative measurement of Os with a spatial resolution of about 70 microns. A linear correlation between Os(+) signal intensity and the known Os concentration was observed over a range of nearly 10,000 in Os concentration with an accuracy of about + or - 10 percent, a minimum detection limit of 7 parts per billion atomic, and a useful yield of 1 percent. Resonance ionization of sputtered atoms samples the dominant neutral-fraction of sputtered atoms and utilizes multiphoton resonance ionization to achieve high sensitivity and to eliminate atomic and molecular interferences.

Blum, J.; Pellin, M. J.; Calaway, W. F.; Young, C. E.; Gruen, D. M.; Hutcheon, I. D.; Wasserburg, G. J.

1990-03-01

398

Blue luminescence from amorphous GaN nanoparticles synthesized {ital in situ} in a polymer  

SciTech Connect

Amorphous GaN nanoparticles were synthesized by the {ital in situ} thermal decomposition of cyclotrigallazane incorporated into a polystyrene{endash}poly({ital N,N}-dimethyl-4-vinylaniline) copolymer. Transmission electron microscopy, energy dispersive x-ray spectrometry, and x-ray photoelectron spectroscopy show that the composite material consists of amorphous GaN nanoparticles (average diameter {approximately}40 nm) well dispersed in the copolymer. The photoluminescence spectra show blue light emission from the amorphous GaN nanoparticles, peaked at {approximately}426 nm. {copyright} {ital 1999 American Institute of Physics.}

Yang, Y.; Leppert, V.J.; Risbud, S.H. [Department of Chemical Engineering and Materials Science, University of California, Davis, California 95616 (United States)] [Department of Chemical Engineering and Materials Science, University of California, Davis, California 95616 (United States); Twamley, B.; Power, P.P. [Department of Chemistry, University of California, Davis, California 95616 (United States)] [Department of Chemistry, University of California, Davis, California 95616 (United States); Lee, H.W. [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)] [Lawrence Livermore National Laboratory, Livermore, California 94551 (United States)

1999-04-01

399

Surface-enhanced Raman spectroscopy as an {\\\\it in situ\\\\\\/} real-time probe of heterogeneous catalytic reactions  

Microsoft Academic Search

Surface-enhanced Raman spectroscopy (SERS) combined with parallel mass spectrometry has been employed as an in-situ real-time probe of surface speciation during several gas-phase heterogeneous catalytic reactions on transition-metal surfaces. The catalysts are ultrathin metallic films electrodeposited onto SERS-active gold, enabling surface vibrational spectroscopic information to be obtained with high temporal resolution ($\\\\approx$1 s) at elevated temperatures (up to 500$\\\\sp\\\\circ$C) and

Christopher Todd Williams

1997-01-01

400

Development and optimisation of a portable micro-XRF method for in situ multi-element analysis of ancient ceramics  

Microsoft Academic Search

Non-destructive analysis of cultural objects by micro-XRF spectrometry is an advantageous multi-element technique that has rapidly developed during the past few years. Portable instruments contribute significantly to the in situ analysis of valuable cultural objects, which cannot be transported to the laboratory. Ancient ceramics are the most common archaeological findings and they carry a significant historical content. Their analysis often

D. N. Papadopoulou; G. A. Zachariadis; A. N. Anthemidis; N. C. Tsirliganis; J. A. Stratis

2006-01-01

401

Gamma-ray spectrometer experiment  

NASA Technical Reports Server (NTRS)

The experiments in gamma-ray spectrometry to determine the geochemical composition of the lunar surface are reported. The theory is discussed of discrete energy lines of natural radioactivity, and the lines resulting from the bombardment of the lunar surface by high energy cosmic rays. The gamma-ray spectrometer used in lunar orbit and during transearth coast is described, and a preliminary analysis of the results is presented.

Arnold, J. R.; Peterson, L. E.; Metzger, A. E.; Trombka, J. I.

1972-01-01

402

Development of a novel electrochemical cell for slab optical waveguide spectroscopy for in situ observation of methylene blue and anions on an electrode\\/electrolyte interface  

Microsoft Academic Search

A new spectroelectrochemical cell for slab optical waveguide (SOWG) spectroscopy was developed in order to observe in situ an electrode\\/electrolyte interface for bulk electrolysis. The new SOWG spectroelectrochemical cell has been evaluated by simultaneous electrochemical-absorption experiments of methylene blue (MB) using cyclic voltammetry (CV) and SOWG spectrometry. CV was performed in the SOWG spectroelectrochemical cell using indium tin oxide (ITO)

Kouji Takahashi; Motoko Koitabashi; Fumiyo Kusu

2005-01-01

403

Miniaturized GC\\/MS instrumentation for in situ measurements: micro gas chromatography coupled with miniature quadrupole array and Paul ion trap mass spectrometers  

Microsoft Academic Search

Miniaturized chemical instrumentation is needed for in situ measurements in planetary exploration and other spaceflight applications where factors such as reduction in payload requirements and enhanced robustness are important. In response to this need, we are continuing to develop miniaturized GC\\/MS instrumentation which combines chemical separations by gas chromatography (GC) with mass spectrometry (MS) to provide positive identification of chemical

Paul M. Holland; Ara Chutjian; Murray R. Darrach; Otto J. Orient

2003-01-01

404

In situ reactivation of glycerol-inactivated coenzyme B12-dependent enzymes, glycerol dehydratase and diol dehydratase.  

PubMed Central

The catalytic properties of coenzyme B12-dependent glycerol dehydratase and diol dehydratase were studied in situ with Klebsiella pneumoniae cells permeabilized by toluene treatment, since the in situ enzymes approximate the in vivo conditions of the enzymes more closely than enzymes in cell-free extracts or cell homogenates. Both dehydratases in situ underwent rapid "suicidal" inactivation by glycerol during catalysis, as they do in vitro. The inactivated dehydratases in situ, however, were rapidly and continually reactivated by adenosine 5'-triphosphate (ATP) and Mn2+ in the presence of free adenosylcobalamin, although in cell-free extracts or in cell homogenates they could not be reactivated at all under the same reaction conditions. ATP was partially replaced by cytidine 5'-triphosphate or guanosine 5'-triphosphate but not by the beta, gamma-methylene analog of ATP in the in situ reactivation. Mn2+ was fully replaced by Mg2+ but only partially by Co2+. Hydroxocoblamin could not replace adenosylcobalamin in reactivation mixtures. The ability to reactivate the glycerol-inactivated dehydratases in situ was only seen in cells grown anaerobically in glycerol-containing media. This suggests that some factor(s) required for in situ reactivation is subject to induction by glycerol. Of the two possible mechanisms of in situ reactivation, i.e., the regeneration of adenosylcobalamin by Co-adenosylation of the bound inactivated coenzyme moiety (B12-adenosylation mechanism) and the displacement of the bound inactivated coenzyme moiety by free adenosyl-cobalamin (B12-exchange mechanism), the former seems very unlikely from the experimental results. Images

Honda, S; Toraya, T; Fukui, S

1980-01-01

405

A GAMMA-SCATTERING SOIL DENSITY GAUGE FOR SUBSURFACE MEASUREMENTS  

Microsoft Academic Search

A gage for in situ measurements of soil densities with an accuracy of ; about l per cent which can be used at depths down to 1000 ft is described. A ; caesium-137 gamma -ray source is separated by a cylindrical lead shield from a ; Geiger counter which detects the gamma -radiation scattered by the soil. The ; optimum

J. F. Cameron; M. S. Bourne

1958-01-01

406

In-situ amino functionalization of carbon nanotubes using ball milling.  

PubMed

A simple chemo-mechanical method is proposed for in-situ amino functionalization of carbon nanotubes (CNTs). Ball milling in the presence of ammonium bicarbonate (NH4HCO3) allowed introduction of functional groups like amine, amide on the surface of CNTs. The milled CNTs were characterized extensively using a particle size analyzer, a transmission electronic microscope, Raman spectrometry, X-ray photoelectron spectroscopy, time-of-flight secondary ion mass spectrometry and surface area measurement to evaluate the influences of ball milling conditions. The results show that CNTs milled with NH4HCO3 were more effectively disentangled and shortened than those without the chemical. The amino termination of the functionalized CNTs makes it possible to covalently bond to polymers and biological systems, as well as the potential applications in electronics industry. PMID:19441385

Ma, Peng Cheng; Wang, Sheng Qi; Kim, Jang-Kyo; Tang, Ben Zhong

2009-02-01

407

In situ testing of superstructure refractories  

SciTech Connect

Almost all glass manufacturers--including Schuller--that have converted to oxy-fuel combustion have encountered superstructure refractory and flue refractory difficulties. Many problems have been encountered because of the higher vapor concentration in oxy-fuel melters that cause undesirable condensate species. Some testing laboratories have facilities for conducting tests on superstructure refractories by simulating the furnace atmosphere and temperature regime. Such tests provide an insight into what can be expected in the installation of a given refractory. However, the simulated atmosphere and the relatively short test period may not inspire confidence. Therefore, Schuller has experimented with in situ testing by placing refractory samples in peepholes, abandoned burner blocks and exhaust ports for relatively long periods of time to gain greater confidence in predicting refractory life for a given application. Furthermore, in situ testing places a refractory sample in close proximity to where it will be used, thus creating a true atmosphere and temperature regime for a given test. In situ testing is intended to determine the best service life for a given glass chemistry, or range of chemistries, that a particular furnace must produce during a campaign. This procedure is something that each operator can perform on any furnace to gain confidence in any new product that a supplier might recommend for future refractory application. The procedure also can be used as head-to-head testing of refractory materials from different suppliers. Also, the material currently being used can be tested against a suggested new material. This article presents the test procedure used and some of the results obtained.

Shamp, D. [Schuller International Inc., Denver, CO (United States)

1997-03-01

408

In situ surface biodegradation of restorative materials.  

PubMed

SUMMARY This study aimed to evaluate the surface characteristics of restorative materials (roughness, hardness, chemical changes by energy-dispersive spectroscopy [EDX], and scanning electron microscopy [SEM]) submitted to in situ biodegradation. Fifteen discs of each material (IPS e.max [EM], Filtek Supreme [FS], Vitremer [VI], Ketac Molar Easymix [KM], and Amalgam GS-80 [AM]) were fabricated in a metallic mold (4.0 mm × 1.5 mm). Roughness, hardness, SEM, and EDX were then evaluated. Fifteen healthy volunteers used a palatal device containing one disc of each restorative material for seven days. After the biodegradation, the roughness, hardness, SEM, and EDX were once again evaluated. Data obtained from the roughness and hardness evaluations were submitted to Kolmogorov-Smirnov and Tukey-Kramer tests (p<0.05). All esthetic restorative materials showed a significant increase in the roughness after biodegradation. Before biodegradation, significant differences in the hardness among the materials were seen: EM>AM>FS>KM>VI. After biodegradation, the hardness was significantly altered among the materials studied: EM>AM>FS=KM>VI, along with a significant increase in the hardness for AM, KM, and VI. SEM images indicated degradation on the surface of all materials, showing porosities, cracks, and roughness. Furthermore, after biodegradation, FS showed the presence of Cl, K, and Ca on the surface, while F was not present on the VI and KM surfaces. EM and AM did not have alterations in their chemical composition after biodegradation. It was concluded that the dental biofilm accumulation in situ on different restorative materials is a material-dependent parameter. Overall, all materials changed after biodegradation: esthetic restorative materials showed increased roughness, confirmed by SEM, and the ionomer materials and silver amalgam showed a significantly higher hardness. Finally, the initial chemical composition of the composite resin and ionomer materials evaluated was significantly altered by the action of the biofilm in situ. PMID:24555699

Padovani, Gc; Fúcio, Sbp; Ambrosano, Gmb; Sinhoreti, Mac; Puppin-Rontani, Rm

2014-01-01

409

In situ, noninvasive characterization of superhydrophobic coatings.  

PubMed

Light scattering was used to measure the time-dependent loss of air entrapped within a submerged microporous hydrophobic surface subjected to different environmental conditions. The loss of trapped air resulted in a measurable decrease in surface reflectivity and the kinetics of the process was determined in real time and compared to surface properties, such as porosity and morphology. The light-scattering results were compared with measurements of skin-friction drag, static contact angle, and contact-angle hysteresis. The in situ, noninvasive optical technique was shown to correlate well with the more conventional methods for quantifying surface hydrophobicity, such as flow slip and contact angle. PMID:21529041

Samaha, Mohamed A; Ochanda, Fredrick O; Tafreshi, Hooman Vahedi; Tepper, Gary C; Gad-el-Hak, Mohamed

2011-04-01

410

Dosage a tres bas niveau de radionucleides a longue periode emetteurs (beta) ou (alpha) par spectrometrie de masse a couplage plasma inductif. (Measurements of (beta) or (alpha) emitter long lived radionuclides using inductively coupled plasma mass spectrometry).  

National Technical Information Service (NTIS)

The measurement of long-lived radionuclides is highly important for characterizing nuclear wastes for their later storage. The main techniques are (alpha) spectrometry, (beta) counting and (gamma) spectrometry. The large period of these isotopes leads to ...

O. Provitina

1993-01-01

411

Neutron Capture gamma-Ray Facility.  

National Technical Information Service (NTIS)

A neutron capture gamma-ray facility was constructed for prompt gamma-ray spectrometry, and its characteristics were measured. In the facility, a neutron beam is extracted from the H-6 horizontal experimental hole of Japan Research Reactor No.3, JAERI, an...

T. Tojo C. Yonezawa S. Koura S. Arai T. Komori

1980-01-01

412

In situ assessment of cell viability.  

PubMed

Cryobiological studies of tissues often require the simultaneous assessment of tissue structure and in situ cellular function. Localization of damage during cryopreservation occurs as a consequence of tissue structure and morphology and as a result of biophysical constraints imposed by diffusion and heat transfer. This study used five experimental model tissue systems: cells in suspension, cells attached to a substrate, a monolayer of cells attached to a substrate, porcine corneas, and intact porcine articular cartilage to examine the efficacy of assessing cell recovery using a novel fluorescent stain (SYTO-13). A graded freezing protocol was used to induce varying degrees of tissue damage. Recovery was assessed in the different tissue model systems using SYTO with ethidium bromide, fluorescein diacetate (FDA) with ethidium bromide, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT). In each of the tissue model systems, the SYTO/EB assessment technique was shown to be equally effective as the existing techniques for the determination of cell recovery. In addition, the properties of fluorescence intensity and rate of release for SYTO were significantly better than those obtained using FDA. Assessment of in situ cell viability was clearly demonstrated using porcine corneas and articular cartilage. The SYTO/EB assay is superior to the existing techniques used for the localization of cell damage in tissues after cryopreservation. PMID:9786064

Yang, H; Acker, J; Chen, A; McGann, L

1998-01-01

413

Inherently safe in situ uranium recovery.  

SciTech Connect

Expansion of uranium mining in the United States is a concern to some environmental groups and sovereign Native American Nations. An approach which may alleviate some problems is to develop inherently safe in situ uranium recovery ('ISR') technologies. Current ISR technology relies on chemical extraction of trace levels of uranium from aquifers that, once mined, can still contain dissolved uranium and other trace metals that are a health concern. Existing ISR operations are few in number; however, high uranium prices are driving the industry to consider expanding operations nation-wide. Environmental concerns and enforcement of the new 30 ppb uranium drinking water standard may make opening new mining operations more difficult and costly. Here we propose a technological fix: the development of inherently safe in situ recovery (ISISR) methods. The four central features of an ISISR approach are: (1) New 'green' leachants that break down predictably in the subsurface, leaving uranium, and associated trace metals, in an immobile form; (2) Post-leachant uranium/metals-immobilizing washes that provide a backup decontamination process; (3) An optimized well-field design that increases uranium recovery efficiency and minimizes excursions of contaminated water; and (4) A combined hydrologic/geochemical protocol for designing low-cost post-extraction long-term monitoring. ISISR would bring larger amounts of uranium to the surface, leave fewer toxic metals in the aquifer, and cost less to monitor safely - thus providing a 'win-win-win' solution to all stakeholders.

Krumhansl, James Lee; Beauheim, Richard Louis; Brady, Patrick Vane; Arnold, Bill Walter; Kanney, Joseph F.; McKenna, Sean Andrew

2009-05-01

414

Molecular cytogenetics using fluorescence in situ hybridization  

SciTech Connect

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 cells. in this approach, termed molecular cytogenetics, the genetic loci to be analyzed are made microscopically visible in single cells using in situ hybridization with nucleic acid probes specific to these loci. To accomplish this, the DNA in the target cells is made single stranded by thermal denaturation and incubated with single-stranded, chemically modified probe under conditions where the probe will anneal only with DNA sequences to which it has high DNA sequence homology. The bound probe is then made visible by treatment with a fluorescent reagent such as fluorescein that binds to the chemical modification carried by the probe. The DNA to which the probe does not bind is made visible by staining with a dye such as propidium iodide that fluoresces at a wavelength different from that of the reagent used for probe visualization. We show in this report that probes are now available that make this technique useful for biological dosimetry, prenatal diagnosis and cancer biology. 31 refs., 3 figs.

Gray, J.W.; Kuo, Wen-Lin; Lucas, J.; Pinkel, D.; Weier, H-U.; Yu, Loh-Chung.

1990-12-07

415

In situ PEM fuel cell water measurements  

SciTech Connect

Efficient PEM (Polymer Electrolyte Membrane) fuel cell performance requires effective water management. To achieve a deeper understanding of water transport and performance issues associated with water management, we have conducted in situ water examinations to help understand the effects of components and operations. High Frequency Resistance (HFR), AC Impedance and Neutron imaging were used to measure water content in operating fuel cells, with various conditions, including current density, relative humidity, inlet flows, flow orientation and variable Gas Diffusion Layer (GDL) properties. High resolution neutron radiography was used to image fuel cells during a variety of conditions. The effect of specific operating conditions, including flow direction (co-flow or counter-flow) was examined. Counter-flow operation was found to result in higher water content than co-flow operation, which correlates to lower membrane resistivity. A variety of cells were used to quantify the membrane water in situ during exposure to saturated gases, during fuel cell operation, and during hydrogen pump operation. The quantitative results show lower membrane water content than previous results suggested.

Borup, Rodney L [Los Alamos National Laboratory; Mukundan, Rangachary [Los Alamos National Laboratory; Davey, John R [Los Alamos National Laboratory; Spendelow, Jacob S [Los Alamos National Laboratory; Hussey, Daniel S [NIST; Jacobson, David L [NIST; Arif, Muhammad [NIST

2009-01-01

416

In situ gelling properties of anionic thiomers.  

PubMed

The aim of this study was to investigate in situ crosslinking systems of anionic thiolated polymers. In order to accelerate the increase in dynamic viscosity of thiolated polymers (thiomers), they were combined with hydrogen peroxide, carbamide peroxide and ammonium persulfate. Thiomers (pectin-cysteine (Pec-Cys), sodium carboxymethylcellulose-cysteine (NaCMC-Cys) and poly(acrylic acid)-cysteine (PAA-Cys)) were synthesized via amide bond formation between the carboxylic acid group of polymers and the primary amino group of l-cysteine. The rheological properties of 1% (m/v) thiomer solutions with oxidizing agents were compared by oscillatory measurements over time (120?min). Pec-Cys and NaCMC-Cys with hydrogen and carbamide peroxide showed a sol-gel phase transition within a few minutes and scored up to 13,000-fold increase in dynamic viscosity. Furthermore, only thiomers exhibiting a polysaccharide backbone (Pec-Cys and NaCMC-Cys) showed a significant increase in viscosity (p?in situ gelling liquid/semisolid formulations or in tissue engineering. PMID:22324362

Hintzen, Fabian; Laffleur, Flavia; Sakloetsakun, Duangkamon; Leithner, Katharina; Bernkop-Schnürch, Andreas

2012-12-01

417

Natural attenuation processes during in situ capping.  

PubMed

Chlorinated solvents are common groundwater contaminants that threaten surface water quality and benthic health when present in groundwater seeps. Aquatic sediments can act as natural biobarriers to detoxify chlorinated solvent plumes via reductive dechlorination. In situ sediment capping, a remedial technique in which clean material is placed at the sediment-water interface, may alter sedimentary natural attenuation processes. This research explores the potential of Anacostia River sediment to naturally attenuate chlorinated solvents under simulated capping conditions. Results of microcosm studies demonstrated that intrinsic dechlorination of dissolved-phase PCE to ethene was possible, with electron donor availability controlling microbial activity. A diverse microbial community was present in the sediment, including multiple Dehalococcoides strains indicated by the amplification of the reductive dehalogenases tceA, vcrA, and bvcA. An upflow column simulating a capped sediment bed subject to PCE-contaminated groundwater seepage lost dechlorination activity with time and only achieved complete dechlorination when microorganisms present in the sediment were provided electron donor. Increases in effluent chloroethene concentrations during the period of biostimulation were attributed to biologically enhanced desorption and the formation of less sorptive dechlorination products. These findings suggest that in situ caps should be designed to account for reductions in natural biobarrier reactivity and for the potential breakthrough of groundwater contaminants. PMID:17822095

Himmelheber, David W; Pennell, Kurt D; Hughes, Joseph B

2007-08-01

418

GAS TURBINE REHEAT USING IN SITU COMBUSTION  

SciTech Connect

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 Task 1, Blade Path Aerodynamics, design options were evaluated using CFD in terms of burnout, increase of power output, and possible hot streaking. It was concluded that Vane 1 injection in a conventional 4-stage turbine was preferred. Vane 2 injection after vane 1 injection was possible, but of marginal benefit. In Task 2, Combustion and Emissions, detailed chemical kinetics modeling, validated by Task 3, Sub-Scale Testing, experiments, resulted in the same conclusions, with the added conclusion that some increase in emissions was expected. In Task 4, Conceptual Design and Development Plan, Siemens Westinghouse power cycle analysis software was used to evaluate alternative in situ reheat design options. Only single stage reheat, via vane 1, was found to have merit, consistent with prior Tasks. Unifying the results of all the tasks, a conceptual design for single stage reheat utilizing 24 holes, 1.8 mm diameter, at the trailing edge of vane 1 is presented. A development plan is presented.

D.M. Bachovchin; T.E. Lippert; R.A. Newby P.G.A. Cizmas

2004-05-17

419

In situ stabilization of entrapped elemental mercury.  

PubMed

Elemental mercury is a dense immiscible fluid which gets entrapped as residual mercury in the pore spaces of the subsurface during improper disposals and accidental spills. This paper investigates in situ stabilization of entrapped elemental mercury to mercury sulphide using aqueous sodium polysulphide solution. Batch experiments showed 100% conversion efficiency of elemental mercury to mercury sulphide in a period of 96 h with sodium polysulphide/elemental mercury molar ratio of 1. XRD analysis identified the precipitate formed as mercury sulphide. Micromodel experiments, with glass beads as porous media, further demonstrated in situ stabilization of entrapped mercury under different residual mercury saturations. It was found that in a period of 10 days, 10% of entrapped mercury was stabilized as mercury sulphide, 0.088% was removed as dissolved mercury and the remaining elemental mercury was retained in porous media encapsulated by the newly formed mercury sulphide precipitate. However, there was no leaching of mercury from the micromodel effluent once stabilization was achieved. PMID:24080327

Devasena, M; Nambi, Indumathi M

2013-11-30

420

Dimensional characterisation of collagen constructs in situ  

NASA Astrophysics Data System (ADS)

We present results of a non contacting instrument based on the confocal scanning technique for assessing the thickness and structure of collagen substrates and tissue constructs. There is an unmet need in the creation of tissue constructs to quantitatively evaluate their dimensional characteristics during manufacture. With this knowledge more effective structures can be produced. The measurement is complicated by the need to make these measurements in situ. For many processes, including the plastic compression of collagen gels for generating 3D structures, the constructs are situated in a liquid solution contained in a well plate or similar container. It is therefore necessary to perform the measurements through an interfering medium and this confounds many measurement techniques. A system has therefore been developed that utilizes a scanning confocal arrangement to accurately measure the dimensional characteristics of these constructs in situ. A fiber based optical arrangement using compact, proven components from the telecommunications industry has been integrated into a dedicated system architecture so that the constructs can be measured whilst in production. This architecture is particularly important due to the "wet" nature of the samples. The meter can measure constructs with thicknesses from a few tens of micrometers up to 0.9 millimeters with sub-micrometer resolution. Results are presented that show how the meter has been used to evaluate changes in these collagen constructs whilst in production. This was little understood prior to these measurements and the greater understanding of how the materials behave has allowed the process to be greatly improved.

Taylor, R.; Reynolds, J.; Chikkanna, B.; Daly, D.; Brown, R. A.; Tan, N. S.

2014-02-01

421

In Situ Instruments: Overview of In Situ Instruments for Deployment in Extreme Environments  

NASA Technical Reports Server (NTRS)

This presentation reviews the design and specifications for several instruments for deployment in extreme environments. The instruments are: (1) In Situ Geochronology Instrument, (2) Laser Ablation Sampling Instrument, (3) Micro Hygrometer (4) Micro Lidar, (5) Atmospheric Electron X-Ray Spectrometer and (6) Nuclear Magnetic Resonance Spectrometer. Included in the descriptions are the contact people and the objective of each instrument.

Taylor, M.; Cardell, G.

2000-01-01

422

Aromatase and in situ estrogen production in DCIS (ductal carcinoma in situ) of human breast  

Microsoft Academic Search

Ductal carcinoma in situ or DCIS belongs to intraductal proliferative lesions, which are a group of cytologically and architecturally diverse ductal proliferations, typically originating from the terminal duct–lobular units. In these intraductal proliferative diseases, estrogens are considered to be involved in the progression of the disease especially from ductal non-neoplastic hyperplasia to DCIS and possibly development of invasive carcinoma from

Hironobu Sasano; Yasuhiro Miki; Rie Shibuya; Takashi Suzuki

2010-01-01

423

Application of in-situ measurement to determine 137Cs in the Swiss Alps.  

PubMed

Establishment of (137)Cs inventories is often used to gain information on soil stability. The latter is crucial in mountain systems, where ecosystem stability is tightly connected to soil stability. In-situ measurements of (137)Cs in steep alpine environments are scarce. Most studies have been carried out in arable lands and with Germanium (Ge) detectors. Sodium Iodide (NaI) detector system is an inexpensive and easy to handle field instrument, but its validity on steep alpine environments has not been tested yet. In this study, a comparison of laboratory measurements with GeLi detector and in-situ measurements with NaI detector of (137)Cs gamma soil radiation has been done in an alpine catchment with high (137)Cs concentration (Urseren Valley, Switzerland). The aim of this study was to calibrate the in-situ NaI detector system for application on steep alpine slopes. Replicate samples from an altitudinal transect through the Urseren Valley, measured in the laboratory with a GeLi detector, showed a large variability in (137)Cs activities at a meter scale. This small-scale heterogeneity determined with the GeLi detector is smoothed out by uncollimated in-situ measurements with the NaI detector, which provides integrated estimates of (137)Cs within the field of view (3.1 m(2)) of each measurement. There was no dependency of (137)Cs on pH, clay content and carbon content, but a close relationship was determined between measured (137)Cs activities and soil moisture. Thus, in-situ data must be corrected for soil moisture. Close correlation (R(2) = 0.86, p < 0.0001) was found for (137)Cs a