Development of AMS procedure for measurement of 93Zr

Science.gov (United States)

Lu, Wenting; Collon, Philippe; Kashiv, Yoav; Bowers, Matthew; Robertson, Daniel; Schmitt, Christopher

2011-10-01

The procedure for measuring 93Zr (t1/2 = 1.5 Ma) by AMS is currently being developed at the Nuclear Science Lab at the University of Notre Dame and we report on first experiments performed in this direction. AMS detection of 93Zr can potentially be applied to address astrophysical and environmental issues: (1) the measurement of the 92Zr(n,γ)93Zr reaction cross-section at nucleosynthesis s-process relevant temperatures, (2) the search for potential live 93Zr from a supernova in deep sea sediments, (3) hydrological and radioactive waste tracing. The measurement of 93Zr requires adequate separation from its stable isobar 93Nb. We are currently working on optimizing this separation by using the GasFilled Magnet technique with additional multiple dE measurements in a focal plane ionization chamber.

Magnetic susceptibility measurements on Bi - Sn alloys

International Nuclear Information System (INIS)

Mustaffa bin Haji Abdullah

1985-01-01

Magnetic susceptibility measurements on eight samples of tin-rich and three samples of bismuth-rich Bi-Sn alloys were made from 85K to 300K by Faraday's method. The susceptibilities of the eight tin-rich samples are positive and greater than the susceptibility of pure tin. The values are approximately constant at low temperatures but decreasing a little bit with increasing temperature. This result is interpreted as due to the predominant contribution of the Pauli spin paramagnetic susceptibility. A small decrease in susceptibility with temperature is interpreted as due to the effect of the second order term in the expression for spin paramagnetic susceptibility. The fluctuation of the susceptibility for alloys of different composition is interpreted as due to the effect of the density of states at the Fermi levels. The three samples of bismuth-rich alloys show a transition to diamagnetic property, where the diamagnetism is increased with temperature. This result is predominant and due to the diamagnetic contribution from the ions. The increase in susceptibility with temperature is interpreted as due to an increase in the effective radii of the ions due to thermal expansion. (author)

Intraspecies differences in natural susceptibility to amphotericine B of clinical isolates of Leishmania subgenus Viannia.

Directory of Open Access Journals (Sweden)

Carlos Franco-Muñoz

Full Text Available Amphotericin B (AmB is a recommended medication for the treatment of cutaneous and mucosal leishmaniasis in cases of therapeutic failure with first-line medications; however, little is known about the in vitro susceptibility to AmB of clinical isolates of the subgenus Viannia, which is most prevalent in South America. This work aimed to determine the in vitro susceptibility profiles to AmB of clinical isolates of the species L. (V. panamensis, L. (V. guyanensis and L. (V. braziliensis. In vitro susceptibility to AmB was evaluated for 65 isolates. Macrophages derived from the U937 cell line were infected with promastigotes and exposed to different AmB concentrations. After 96 hours, the number of intracellular amastigotes was quantified by qPCR, and median effective concentration (EC50 was determined using the PROBIT model. The controls included sensitive strains and experimentally derived less sensitive strains generated in vitro, which presented EC50 values up to 7.57-fold higher than the values of the sensitive strains. The isolates were classified into groups according to their in vitro susceptibility profiles using Ward's hierarchical method. The susceptibility to AmB differed in an intraspecies-specific manner as follows: 28.21% (11/39 of L. (V. panamensis strains, 50% (3/6 of L. (V. guyanensis strains and 34.61% (9/26 of L. (V. braziliensis strains were classified as less sensitive. The latter subset featured three susceptibility groups. We identified Colombian isolates with different AmB susceptibility profiles. In addition, the capacity of species of subgenus Viannia to develop lower susceptibility to AmB was demonstrated in vitro. These new findings should be considered in the pharmacovigilance of AmB in Colombia and South America.

Sophistication of 14C measurement at JAEA-AMS-MUTSU. Attempt on a small quantity of sample

International Nuclear Information System (INIS)

Tanaka, Takayuki; Kabuto, Shoji; Kinoshita, Naoki; Yamamoto, Nobuo

2010-01-01

In the investigations on substance dynamics using the molecular weight and chemical fractionation, the utilization of 14 C measurement by an accelerator mass spectrometry (AMS) have started. As a result of the fractionation, sample contents required for AMS measurement have been downsized. We expect that this trend toward a small quantity of sample will be steadily accelerated in the future. As 14 C measurement by AMS established at Mutsu office require about 2 mg of sample content at present, our AMS lags behind the others in the trend. We try to downsize the needed sample content for 14 C measurement by our AMS. In this study, we modified the shape of the target-piece in which the sample is packed and which is regularly needed to radiocarbon measurement by our AMS. Moreover, we improved on the apparatus needed to pack the sample. As a result of the improvement, we revealed that it is possible to measure the 14 C using our AMS even by the amount of the sample of about 0.5 mg. (author)

Progress on multi-nuclide AMS of JAEA-AMS-TONO

Science.gov (United States)

Saito-Kokubu, Yoko; Matsubara, Akihiro; Miyake, Masayasu; Nishizawa, Akimitsu; Ohwaki, Yoshio; Nishio, Tomohiro; Sanada, Katsuki; Hanaki, Tatsumi

2015-10-01

The JAEA-AMS-TONO (Japan Atomic Energy Agency's Accelerator Mass Spectrometer established at the Tono Geoscience Center) facility has been used for the dating of geological samples. The AMS system is versatile, based on a 5 MV tandem Pelletron-type accelerator. Since its establishment in 1997, the AMS system has been used for measurement of carbon-14 (14C) mainly for 14C dating studies in neotectonics and hydrogeology, in support of JAEA's research on geosphere stability applicable to the long-term isolation of high-level radioactive waste. Results of the measurement of 14C in soils and plants has been applied to the dating of fault activity and volcanism. Development of beryllium-10 (10Be) and aluminum-26 (26Al) AMS systems are now underway to enhance the capability of the multi-nuclide AMS in studies of dating by cosmogenic nuclides. The 10Be-AMS system has already been used for routine measurements in applied studies and improvements of the measurement technique have been made. Now we plan to fine tune the system and perform test measurements to develop the 26Al-AMS system.

Progress on multi-nuclide AMS of JAEA-AMS-TONO

Energy Technology Data Exchange (ETDEWEB)

Saito-Kokubu, Yoko, E-mail: kokubu.yoko@jaea.go.jp [Japan Atomic Energy Agency, Toki, Gifu 509-5102 (Japan); Matsubara, Akihiro [Japan Atomic Energy Agency, Toki, Gifu 509-5102 (Japan); Miyake, Masayasu; Nishizawa, Akimitsu; Ohwaki, Yoshio; Nishio, Tomohiro; Sanada, Katsuki [Pesco Corp., Ltd., Toki, Gifu 509-5123 (Japan); Hanaki, Tatsumi [Japan Atomic Energy Agency, Toki, Gifu 509-5102 (Japan)

2015-10-15

The JAEA-AMS-TONO (Japan Atomic Energy Agency’s Accelerator Mass Spectrometer established at the Tono Geoscience Center) facility has been used for the dating of geological samples. The AMS system is versatile, based on a 5 MV tandem Pelletron-type accelerator. Since its establishment in 1997, the AMS system has been used for measurement of carbon-14 ({sup 14}C) mainly for {sup 14}C dating studies in neotectonics and hydrogeology, in support of JAEA’s research on geosphere stability applicable to the long-term isolation of high-level radioactive waste. Results of the measurement of {sup 14}C in soils and plants has been applied to the dating of fault activity and volcanism. Development of beryllium-10 ({sup 10}Be) and aluminum-26 ({sup 26}Al) AMS systems are now underway to enhance the capability of the multi-nuclide AMS in studies of dating by cosmogenic nuclides. The {sup 10}Be-AMS system has already been used for routine measurements in applied studies and improvements of the measurement technique have been made. Now we plan to fine tune the system and perform test measurements to develop the {sup 26}Al-AMS system.

Neutron capture cross section measurements of $^{238}$U, $^{241}$Am and $^{243}$Am at n_TOF

CERN Multimedia

Koehler, P E; Plag, R

The increase of the world energy demand and the need of low carbon energy sources have triggered the renaissance and/or enhancement of nuclear energy in many countries. Fundamental nuclear physics can contribute in a practical way to the sustainability and safety of the nuclear energy production and the management of the nuclear waste. There exists a series of recent studies which address the most relevant isotopes, decay data, nuclear reaction channels and energy ranges which have to be investigated in more detail for improving the design of different advanced nuclear systems [1] and nuclear fuel cycles [2]. In this proposal, we aim at the measurement of the neutron capture cross sections of $^{238}$U, $^{241}$Am and $^{243}$Am. All three isotopes are listed in the NEA High Priority Request List [37], are recommended for measurements [1] and play an important role in the nuclear energy production and fuel cycle scenarios. The measurements will provide as well valuable nuclear structure data necessary for the...

Materials with low DC magnetic susceptibility for sensitive magnetic measurements

International Nuclear Information System (INIS)

Khatiwada, R; Kendrick, R; Khosravi, M; Peters, M; Smith, E; Snow, W M; Dennis, L

2016-01-01

Materials with very low DC magnetic susceptibility have many scientific applications. To our knowledge however, relatively little research has been conducted with the goal to produce a totally nonmagnetic material. This phrase in our case means after spatially averaging over macroscopic volumes, it possesses an average zero DC magnetic susceptibility. We report measurements of the DC magnetic susceptibility of three different types of nonmagnetic materials at room temperature: (I) solutions of paramagnetic salts and diamagnetic liquids, (II) liquid gallium–indium alloys and (III) pressed powder mixtures of tungsten and bismuth. The lowest measured magnetic susceptibility among these candidate materials is in the order of 10 −9 cgs volume susceptibility units, about two orders of magnitude smaller than distilled water. In all cases, the measured concentration dependence of the magnetic susceptibility is consistent with that expected for the weighted sum of the susceptibilities of the separate components within experimental error. These results verify the well-known Wiedemann additivity law for the magnetic susceptibility of inert mixtures of materials and thereby realize the ability to produce materials with small but tunable magnetic susceptibility. For our particular scientific application, we are also looking for materials with the largest possible number of neutrons and protons per unit volume. The gallium–indium alloys fabricated and measured in this work possess to our knowledge the smallest ratio of volume magnetic susceptibility to nucleon number density per unit volume for a room temperature liquid, and the tungsten-bismuth pressed powder mixtures possess to our knowledge the smallest ratio of volume magnetic susceptibility to nucleon number density per unit volume for a room temperature solid. This ratio is a figure of merit for a certain class of precision experiments that search for possible exotic spin-dependent forces of Nature. (paper)

Total and (n, 2n) neutron cross section measurements on 241Am

International Nuclear Information System (INIS)

Sage, C.

2009-01-01

Neutron induced reaction cross sections on 241 Am have been measured at the IRMM in Geel, Belgium, in the frame of a collaboration between the EC Joint Research Centres IRMM and ITU and French laboratories from CNRS and CEA. Raw material coming from the Atalante facility of CEA Marcoule has been transformed into suitable AmO 2 samples embedded in Al 2 O 3 and Y 2 O 3 matrices. The irradiations for the 241 Am(n, 2n) 240 Am reaction cross section measurement were carried out at the 7 MV Van de Graaff accelerator using the activation technique with quasi mono-energetic neutrons from 8 to 21 MeV produced via the D(d, n) 3 He and the T(d, n) 4 He reactions. The cross section was determined relative to the 27 Al(n, α) 24 Na standard cross section and was investigated for the first time above 15 MeV. The induced activity was measured off-line by standard γ-ray spectrometry using a high purity Ge detector. A special effort was made for the estimation of the uncertainties and the correlations between our experimental points. A different sample of the same isotope 241 Am has been measured in transmission and capture experiments in the resolved resonance region at the neutron ToF facility GELINA. The transmission measurement was performed in two campaigns, with an upgrade of the whole data acquisition system in between, followed by an investigation of its new performances. A preliminary analysis of the resonance parameters tends to confirm the recent evaluation to a higher value for the cross section at the bottom of the first resonances. A new design of C 6 D 6 detectors for capture measurements has been studied, but the data reduction and analysis of the measurement are not part of this work. (author) [fr

AMS Measurement of 36Cl with a Q3D Magnetic Spectrometer at CIAE

International Nuclear Information System (INIS)

Li Chaoli; He Ming; Wu Shaoyong; Li Zhenyu; Liu Jiancheng; Dong Kejun; Jiang Shan; Zhang Wei; He Xianwen

2012-01-01

The ratio of 36 Cl/Cl can determine the exposure age of surface rocks and monitor the secular equilibrium of 36 Cl of sedimentary and igneous rock in groundwater. Due to the uncertainty effects of different chemical separation processes for removing 36 S, there is a high degree of uncertainty in 36 Cl accelerator mass spectrometry (AMS) measurements if the ratio of 36 Cl/Cl is lower than 10 -14 . A 36 Cl AMS higher sensitivity measurement has been set up by using a ΔE-Q3D method at the China Institute of Atomic Energy (CIAE). The performances of ΔE-Q3D method for 36 Cl-AMS measurement had been systemically studied. The experimental results show that the ΔE-Q3D method has a higher isobar suppression factor. Taking advantage of direct removing 36 S, the sample preparation can be simplified and the uncertainty effects of different chemical separation processes can be reduced in 36 Cl AMS measurements.

Precision and reproducibility in AMS radiocarbon measurements.

Energy Technology Data Exchange (ETDEWEB)

Hotchkis, M.A.; Fink, D.; Hua, Q.; Jacobsen, G.E.; Lawson, E. M.; Smith, A.M.; Tuniz, C. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

1996-12-31

Accelerator Mass Spectrometry (AMS) is a technique by which rare radioisotopes such as {sup 14}C can be measured at environmental levels with high efficiency. Instead of detecting radioactivity, which is very weak for long-lived environmental radioisotopes, atoms are counted directly. The sample is placed in an ion source, from which a negative ion beam of the atoms of interest is extracted, mass analysed, and injected into a tandem accelerator. After stripping to positive charge states in the accelerator HV terminal, the ions are further accelerated, analysed with magnetic and electrostatic devices and counted in a detector. An isotopic ratio is derived from the number of radioisotope atoms counted in a given time and the beam current of a stable isotope of the same element, measured after the accelerator. For radiocarbon, {sup 14}C/{sup 13}C ratios are usually measured, and the ratio of an unknown sample is compared to that of a standard. The achievable precision for such ratio measurements is limited primarily by {sup 14}C counting statistics and also by a variety of factors related to accelerator and ion source stability. At the ANTARES AMS facility at Lucas Heights Research Laboratories we are currently able to measure {sup 14}C with 0.5% precision. In the two years since becoming operational, more than 1000 {sup 14}C samples have been measured. Recent improvements in precision for {sup 14}C have been achieved with the commissioning of a 59 sample ion source. The measurement system, from sample changing to data acquisition, is under common computer control. These developments have allowed a new regime of automated multi-sample processing which has impacted both on the system throughput and the measurement precision. We have developed data evaluation methods at ANTARES which cross-check the self-consistency of the statistical analysis of our data. Rigorous data evaluation is invaluable in assessing the true reproducibility of the measurement system and aids in

Precision and reproducibility in AMS radiocarbon measurements.

Energy Technology Data Exchange (ETDEWEB)

Hotchkis, M A; Fink, D; Hua, Q; Jacobsen, G E; Lawson, E M; Smith, A M; Tuniz, C [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

1997-12-31

Accelerator Mass Spectrometry (AMS) is a technique by which rare radioisotopes such as {sup 14}C can be measured at environmental levels with high efficiency. Instead of detecting radioactivity, which is very weak for long-lived environmental radioisotopes, atoms are counted directly. The sample is placed in an ion source, from which a negative ion beam of the atoms of interest is extracted, mass analysed, and injected into a tandem accelerator. After stripping to positive charge states in the accelerator HV terminal, the ions are further accelerated, analysed with magnetic and electrostatic devices and counted in a detector. An isotopic ratio is derived from the number of radioisotope atoms counted in a given time and the beam current of a stable isotope of the same element, measured after the accelerator. For radiocarbon, {sup 14}C/{sup 13}C ratios are usually measured, and the ratio of an unknown sample is compared to that of a standard. The achievable precision for such ratio measurements is limited primarily by {sup 14}C counting statistics and also by a variety of factors related to accelerator and ion source stability. At the ANTARES AMS facility at Lucas Heights Research Laboratories we are currently able to measure {sup 14}C with 0.5% precision. In the two years since becoming operational, more than 1000 {sup 14}C samples have been measured. Recent improvements in precision for {sup 14}C have been achieved with the commissioning of a 59 sample ion source. The measurement system, from sample changing to data acquisition, is under common computer control. These developments have allowed a new regime of automated multi-sample processing which has impacted both on the system throughput and the measurement precision. We have developed data evaluation methods at ANTARES which cross-check the self-consistency of the statistical analysis of our data. Rigorous data evaluation is invaluable in assessing the true reproducibility of the measurement system and aids in

Measurement of mass yields from the 241Am(2nth,f reaction at the Lohengrin Spectrometer

Directory of Open Access Journals (Sweden)

Köster U.

2013-03-01

Full Text Available The study of fission yields has a major impact on the characterization and understanding of the fission process and is mandatory for reactor applications. While the yields are known for the major actinides (235U, 239Pu in the thermal neutron-induced fission, only few measurements have been performed on 242Am. The interest of 242Am concerns the reduction of radiotoxicity of 241Am in nuclear wastes using transmutation reactions. This paper presents the measurement of the fission mass yields from the reaction 241Am(2nth,f performed at the Lohengrin mass spectrometer (ILL, France for both the light and the heavy peaks: a total of 41 mass yields have been measured. The experiment was also meant to determine whether there is a difference in mass yields between the isomeric state and the ground state as it exists in fission and capture cross sections. The method used to address this question is based on a repeated measurement of a set of fission mass yields as a function of the ratio between the 242gAm and the 242mAm fission rates. The presented experiment is also a first step towards the measurement of the isotopic fission yields of 242Am.

Magnetic susceptibility measuring probe utilizing a compensation coil

International Nuclear Information System (INIS)

Bonnet, Jean; Fournet, Julien.

1978-01-01

This invention concerns a magnetic susceptibility measuring probe. It is used, inter alia, in logging, to wit continuous logging of the magnetic susceptibility of the ground throughout the length of a bore hole. The purpose of this invention is to increase the sensitivity of this type of probe by creating a side focusing effect . To this end, it provides for the use of a compensation winding, coaxial with the measurement winding and arranged symmetrically to the latter with respect to the centre of the induction windings [fr

Plutonium measurements on the 1 MV AMS system at the Centro Nacional de Aceleradores (CNA)

International Nuclear Information System (INIS)

Chamizo, Elena; Enamorado, Santiago Miguel; Garcia-Leon, Manuel; Suter, Martin; Wacker, Lukas

2008-01-01

Plutonium isotopes have been recently added to the list of radionuclides that can be measured with the new generation of compact AMS facilities. In this paper we present first experimental results concerning the development of the plutonium AMS technique at 680 kV on the 1 MV AMS system at the Centro Nacional de Aceleradores (CNA) in Sevilla, Spain. This is the first compact AMS machine designed and manufactured by High Voltage Engineering Europa. As we demonstrate, the obtained backgrounds for 239,240 Pu, of about 10 6 atoms, and the 239 Pu/ 238 U mass suppression factor, in the range of 10 -9 , compare to the ones achieved on other AMS facilities. With the measurement of reference materials provided by the International Atomic Energy Agency (IAEA-375, IAEA-Soil-6, IAEA-381) and samples already studied on the 600 kV compact ETH/PSI AMS system at Zuerich, we show that the CNA system can be perfectly used for the routine measurement of plutonium isotopes at environmental levels.

New applications of 14C measurements at the Lund AMS Facility

International Nuclear Information System (INIS)

Stenstroem, K.

1995-11-01

Some new applications of accelerator mass spectroscopy (AMS) with 14 C are presented. In the first part the sample preparation used for production of elemental carbon at the Lund AMS facility is described. The second part concerns the release of 14 C from nuclear power plants. In a one-year study, the total airborne discharge of 14 C from two Swedish reactors was measured. In another study, the fraction of 14 CO 2 of the total airborne 14 C release was determined. The third part of the thesis involves the use of 14 C in nuclear medicine. The long-term retention of 14 C-labelled triolein after a fat-malabsorption test has been investigated by means of AMS by analysis of expired CO 2 . The possibilities of using ultra-low amounts of activity for fat-malabsorption tests, employing AMS technique, is demonstrated. In the last part AMS and 14 C-labelled tracers are used in food chemistry studies of interactions between foods and packaging materials. 22 refs, 8 figs, 2 tabs

Neutron capture and (n,2n) measurements on {sup 241}Am

Energy Technology Data Exchange (ETDEWEB)

Vieira, D.J.; Jandel, M.; Bredeweg, T.A.; Bond, E.M.; Clement, R.R.; Couture, A.; Haight, R.C.; O' Donnell, J.M.; Reifarth, R.; Rundberg, R.S.; Ullmann, J.L.; Wilhelmy, J.B.; Wouters, J.M. [Los Alamos National Laboratory, NM (United States); Tonchev, A.P.; Hutcheson, A.; Angell, C.T.; Crowell, A.S.; Fallin, B.; Hammond, S.; Howell, C.R.; Karowowski, H.J.; Kelley, J.H.; Pedroni, R.; Tornow, W. [Triangle Univ. Nuclear Laboratory, Durham, NC (United States); Macri, R.A.; Agvaanluvsan, U.; Becker, J.A.; Dashdorj, D.; Stoyer, M.A.; Wu, C.Y. [Lawrence Livermore National Laboratory, Livermore, CA (United States)

2008-07-01

We report on a set of neutron-induced reaction measurements on {sup 241}Am which are important for nuclear forensics and advanced nuclear reactor design. Neutron capture measurements have been performed on the DANCE detector array at the Los Alamos Neutron Scattering Center (LANSCE). In general, good agreement is found with the most recent data evaluations up to an incident neutron energy of about 300 keV where background limits the measurement. Using mono-energetic neutrons produced in the {sup 2}H(d,n){sup 3}He reaction at the Triangle Universities Nuclear Laboratory (TUNL), we have measured the {sup 241}Am(n,2n) excitation function from 7.6 to 14.5 MeV using the activation method. Good agreement is found with previous measurements, with the exception of the three data points reported by Perdikakis et al. around 11 MeV, where we obtain a much lower cross section that is more consistent with theoretical estimates. (authors)

Magnetic-susceptibility and heat-capacity measurements on PrRhSb

International Nuclear Information System (INIS)

Malik, S.K.; Takeya, H.; Gschneidner, K.A. Jr.

1994-01-01

Magnetic-susceptibility (ac and dc) and heat-capacity measurements have been carried out on the compound PrRhSb. These measurements reveal two magnetic transitions in this compound---one at about 18 K and the other around 6 K. In the dc susceptibility the 18-K transition is evident as the temperature below which a magnetic correlation sets in and the susceptibility is found to be field dependent. The lower transition manifests as a peak in the susceptibility of zero-field-cooled samples which were measured in low applied fields. The electronic-specific-heat coefficient, γ, is found to be 33 mJ/mol K 2 between 40 and 70 K after correcting for the lattice contribution taken to be the same as in its La analog. The γ value is fairly large for a Pr compound and may be indicative of moderately heavy quasiparticles. A Kondo-type interaction of the Pr 4f electrons with the conduction electrons may be responsible for high-magnetic-ordering temperatures and the moderately large γ value in this compound

Applying the anisotropy of magnetic susceptibility technique to the study of the tectonic evolution of the West Spitsbergen Fold-and-Thrust Belt

Directory of Open Access Journals (Sweden)

Katarzyna Dudzisz

2016-12-01

Full Text Available We demonstrate the use of the anisotropy of magnetic susceptibility (AMS method to determine the orientation of the principal tectonic strain directions developed during the formation of the West Spitsbergen Fold-and-Thrust Belt (WSFTB. The AMS measurements and extensive rock-magnetic studies of the Lower Triassic rocks reported here were focused on the recognition of the magnetic fabric, the identification of ferromagnetic minerals and an estimation of the influence of ferro- and paramagnetic minerals on magnetic susceptibility. At most sites, the paramagnetic minerals controlled the magnetic susceptibility, and at only one site the impact of ferromagnetic minerals was higher. The AMS technique documented the presence of different types of magnetic fabrics within the sampled sites. At two sites, a normal (Kmin perpendicular to the bedding magnetic fabric of sedimentary origin was detected. This was associated with a good clustering of the maximum AMS axes imposed by tectonic strain. The Kmax magnetic lineation directions obtained here parallel the general NNW–SSE trend of the WSFTB fold axial traces and thrust fronts. The two other investigated sites possessed mixed and inverted fabrics, the latter of which appear to reflect the presence of iron-bearing carbonates.

Measuring Nematic Susceptibilities from the Elastoresistivity Tensor

Science.gov (United States)

Hristov, A. T.; Shapiro, M. C.; Hlobil, Patrick; Maharaj, Akash; Chu, Jiun-Haw; Fisher, Ian

The elastoresistivity tensor mijkl relates changes in resistivity to the strain on a material. As a fourth-rank tensor, it contains considerably more information about the material than the simpler (second-rank) resistivity tensor; in particular, certain elastoresistivity coefficients can be related to thermodynamic susceptibilities and serve as a direct probe of symmetry breaking at a phase transition. The aim of this talk is twofold. First, we enumerate how symmetry both constrains the structure of the elastoresistivity tensor into an easy-to-understand form and connects tensor elements to thermodynamic susceptibilities. In the process, we generalize previous studies of elastoresistivity to include the effects of magnetic field. Second, we describe an approach to measuring quantities in the elastoresistivity tensor with a novel transverse measurement, which is immune to relative strain offsets. These techniques are then applied to BaFe2As2 in a proof of principle measurement. This work is supported by the Department of Energy, Office of Science, Basic Energy Sciences, Materials Sciences and Engineering Division, under Contract DE-AC02-76SF00515.

Translation balance for measuring magnetic susceptibilities at high or low temperatures (1962)

International Nuclear Information System (INIS)

Blaise, A.; Peuch, M.A.

1962-01-01

A translation balance is described for the measurement of the magnetic susceptibilities of liquids or solids in the temperature range from 1.7 to 1400 deg. K. Measurements are made within a magnetic field adjustable from 3400 to 16000 oersteds, in any desired atmosphere. Susceptibilities between 10 -8 and 10 -4 u.e.m. C.G.S., can be measured. (authors) [fr

The influence of impurities for cross section measurement of {sup 241,243}Am(n,f) reactions

Energy Technology Data Exchange (ETDEWEB)

Kai, Tetsuya; Kobayashi, Katsuhei; Yamamoto, Shuji; Fujita, Yoshiaki; Kimura, Itsuro; Miyoshi, Mitsuharu; Yamamoto, Hideki [Kyoto Univ. (Japan); Shinohara, Nobuo

1997-03-01

The influence of the impurities on the fission cross section measurements for {sup 241}Am and {sup 243}Am has been investigated with the practical results. Following cases have been considered as the influence of impurities; (a) experiments with the {sup 241}Am sample that contains impurities originally, and (b) experiments with the {sup 243}Am sample that contains impurities produced by {alpha}, {beta} decays after the chemical purification. The present study has demonstrated the usefulness of pure samples by the comparison of the experiments using the sample on the market with those using the pure sample processed by the authors. Particularly on the case (b), the correction of the impurity through the periodical measurements was experimentally performed (about 18% around 0.3 eV in 4 weeks after the chemical purification). (author)

On a low intensity 241 Am Compton spectrometer for measurement ...

Indian Academy of Sciences (India)

In this paper, a new design and construction of a low intensity (100 mCi) 241Am -ray Compton spectrometer is presented. The planar spectrometer is based on a small disc source with the shortest geometry. Measurement of the momentum density of polycrystalline Al is used to evaluate the performance of the new design.

Progress in AMS measurement of "1"2"9I and "1"4C at CIAE

International Nuclear Information System (INIS)

Yang Xuran; Dong, K.J.; Shan, J.; He Ming; Xie, L.B.

2013-01-01

Twenty-four years have passed since the AMS was built at China Institute of Atomic Energy (CIAE) in 1989. We have measured "2"3"6U, "1"8"2Hf, "5"9Ni and other elements. Recently, the routine method of measuring the "1"2"9I concentration in air particle samples using AMS have been set up due to it has great advantages to measure long-lived radioisotopes. For the applications, "1"2"9I could be used for monitoring nuclear environment. "1"2"9I was collected in air particle samples after the accident of Fukushima nuclear power plant and measured at the China Institute of Atomic Energy (CIAE) by using AMS, the result show that "1"2"9I derived from FNPP accident had been arrived in Beijing early on March 26th and "1"2"9I concentration had been greatly increased relative to March 20th. On the other hand, a new system to measure "1"4C of AMS will be designed for the application in bio-medical science: urea breath test (UBT). UBT has been carried out widely by using carbon isotope of "1"3C and "1"4C, respectively, in the world. They are two tracers with different measurement methods but applied by the same principle. Optimizing UBT methods with using "1"4C is the priori for the diagnosis of helicobacter pylori in the future. (author)

AC susceptibility and NQR measurements on CeCu6 below 5 mK

International Nuclear Information System (INIS)

Jin, C.; Lee, D.M.; Pollack, L.; Smith, E.N.; Markert, J.T.; Maple, M.B.; Hinks, D.G.

1994-01-01

We have measured the zero field ac magnetic susceptibility of single and polycrystalline CeCu 6 samples down to 100 μK. For the single crystal sample, the susceptibility shows pronounced anisotropic behavior with respect to the crystal orientation. At ∼3 mK the susceptibility along two different crystal orientations shows a broad peak, and at 500 μK the susceptibility shows a second peak along one orientation and a plateau along the other. The susceptibility of the polycrystalline sample has a similar peak at 3 mK. NQR measurements are under way to study the Cu nuclear spin system in this compound in order to gain additional information about the nature of the peaks. (orig.)

Magnetic fabric and flow direction in the Ediacaran Imider dyke swarms (Eastern Anti-Atlas, Morocco), inferred from the Anisotropy of Magnetic Susceptibility (AMS)

Science.gov (United States)

Otmane, Khadija; Errami, Ezzoura; Olivier, Philippe; Berger, Julien; Triantafyllou, Antoine; Ennih, Nasser

2018-03-01

Located in the Imiter Inlier (Eastern Saghro, Anti-Atlas, Morocco), Ediacaran volcanic dykes have been studied for their petrofabric using Anisotropy of Magnetic Susceptibility (AMS) technique. Four dykes, namely TF, TD, FF and FE show andesitic compositions and are considered to belong to the same dyke swarm. They are oriented respectively N25E, N40E, N50E, and N10E and have been emplaced during a first tectonic event. The dyke FW, oriented N90E displays a composition of alkali basalt and its emplacement is attributed to a subsequent tectonic event. These rocks are propylitized under greenschist facies conditions forming a secondary paragenesis constituted by calcite, chlorite, epidote and sericite. The dykes TF, TD, FF and FE are sub-volcanic calc-alkaline, typical of post-collisional basalts/andesites, belonging to plate margin andesites. The FW dyke shows a within-plate basalt signature; alkaline affinity reflecting a different petrogenetic process. The thermomagnetic analyses show a dominantly ferromagnetic behaviour in the TF dyke core carried by single domain Ti-poor magnetite, maghemite and pyrrhotite. The dominantly paramagnetic susceptibilities in TF dyke rims and TD, FE, FF and FW dykes are controlled by ilmenite, amphibole, pyroxene and chlorite. The magnetic fabrics of the Imider dykes, determined by our AMS study, allows us to reconstitute the tectonic conditions which prevailed during the emplacement of these two generations of volcanic dykes. The first tectonic event was characterized by a roughly NE-SW compression and the second tectonic event is characterized by an E-W shortening followed by a relaxation recording the end of the Pan-African orogeny in the eastern Anti-Atlas.

Resident alveolar macrophages are susceptible to and permissive of Coxiella burnetii infection.

Directory of Open Access Journals (Sweden)

Matthew Calverley

Full Text Available Coxiella burnetii, the causative agent of Q fever, is a zoonotic disease with potentially life-threatening complications in humans. Inhalation of low doses of Coxiella bacteria can result in infection of the host alveolar macrophage (AM. However, it is not known whether a subset of AMs within the heterogeneous population of macrophages in the infected lung is particularly susceptible to infection. We have found that lower doses of both phase I and phase II Nine Mile C. burnetii multiply and are less readily cleared from the lungs of mice compared to higher infectious doses. We have additionally identified AM resident within the lung prior to and shortly following infection, opposed to newly recruited monocytes entering the lung during infection, as being most susceptible to infection. These resident cells remain infected up to twelve days after the onset of infection, serving as a permissive niche for the maintenance of bacterial infection. A subset of infected resident AMs undergo a distinguishing phenotypic change during the progression of infection exhibiting an increase in surface integrin CD11b expression and continued expression of the surface integrin CD11c. The low rate of phase I and II Nine Mile C. burnetii growth in murine lungs may be a direct result of the limited size of the susceptible resident AM cell population.

Plutonium AMS measurements in Yangtze River estuary sediment

International Nuclear Information System (INIS)

Tims, S.G.; Pan, S.M.; Zhang, R.; Fifield, L.K.; Wang, Y.P.; Gao, J.H.

2010-01-01

The Yangtze River is the largest single source of sediment to the continental shelf of the East China Sea. The quantity of material exported by the river is expected to decrease substantially as a consequence of an extensive continuing program of dam construction within the river catchment. We report here AMS measurements of plutonium isotope concentrations and ratios for selected depth increments from a sediment core, collected from the sub-aqueous delta of the Yangtze River estuary. The Pu derives from atmospheric nuclear weapons testing in the 1950s and 1960s, and is potentially a useful tracer of sediment deposition times in the marine environment. The results show considerable structure in the depth-concentration profile, and offer an excellent opportunity to compare Pu with the more commonly used 137 Cs isotopic tracer. The AMS data show superior sensitivity and indicate that the 240 Pu/ 239 Pu ratio can provide a check on the deposition dates. The changes in the 240 Pu and 239 Pu concentrations and the 240 Pu/ 239 Pu ratios with sediment depth all indicate the possibility of using Pu as a geochronological tool for coastal sediment studies.

Impact of AMS-02 Measurements on Reducing GCR Model Uncertainties

Science.gov (United States)

Slaba, T. C.; O'Neill, P. M.; Golge, S.; Norbury, J. W.

2015-01-01

For vehicle design, shield optimization, mission planning, and astronaut risk assessment, the exposure from galactic cosmic rays (GCR) poses a significant and complex problem both in low Earth orbit and in deep space. To address this problem, various computational tools have been developed to quantify the exposure and risk in a wide range of scenarios. Generally, the tool used to describe the ambient GCR environment provides the input into subsequent computational tools and is therefore a critical component of end-to-end procedures. Over the past few years, several researchers have independently and very carefully compared some of the widely used GCR models to more rigorously characterize model differences and quantify uncertainties. All of the GCR models studied rely heavily on calibrating to available near-Earth measurements of GCR particle energy spectra, typically over restricted energy regions and short time periods. In this work, we first review recent sensitivity studies quantifying the ions and energies in the ambient GCR environment of greatest importance to exposure quantities behind shielding. Currently available measurements used to calibrate and validate GCR models are also summarized within this context. It is shown that the AMS-II measurements will fill a critically important gap in the measurement database. The emergence of AMS-II measurements also provides a unique opportunity to validate existing models against measurements that were not used to calibrate free parameters in the empirical descriptions. Discussion is given regarding rigorous approaches to implement the independent validation efforts, followed by recalibration of empirical parameters.

Precise measurement of cosmic ray fluxes with the AMS-02 experiment

Energy Technology Data Exchange (ETDEWEB)

Vecchi, Manuela, E-mail: manuela.vecchi@ifsc.usp.br [Instituto de Física de São Carlos, Universidade de São Paulo, CP 369, 13560-970, São Carlos, SP (Brazil)

2015-12-17

The AMS-02 detector is a large acceptance magnetic spectrometer operating onboard the International Space Station since May 2011. The main goals of the detector are the search for antimatter and dark matter in space, as well as the measurement of cosmic ray composition and flux. In this document we present precise measurements of cosmic ray positrons, electrons and protons, collected during the first 30 months of operations.

Activation measurements for fast neutrons. Part B. 63Ni measurements by accelerator mass spectrometry (AMS)

International Nuclear Information System (INIS)

Straume, Tore; Rugel, Georg; Marchetti, Alfredo A.

2005-01-01

The AMS-measurements of 63 Ni in copper samples obtained from different distances in Hiroshima represent the first detection of fast neutrons after more than 50 years, and the first reliable bomb-induced fast neutron measurements beyond 700 m from the hypocenter. A major significance of these 63 Ni results is that they provide, for the first time, fast neutron measurements at the distances most relevant to atomic-bomb survivor locations (900-1,500 m). The measurement of 63 Ni in copper samples using AMS provides a substantial improvement in fast neutron detection compared with the 32 P measurements made in 1945. For example, the measurement-to-background ratio at about 400 m from the hypocenter is about 55 for 63 Ni and only about 2 for the 32 P measurements. Also, the 63 Ni measurements reach background levels at about 1,800 m from the hypocenter compared with only about 700 m for 32 P. At distances of ∼1,800 m from the hypocenter, out to at least 5,000 meters, the measurements appear to level off at a value on the order of 7x10 4 atoms of 63 Ni/g of Cu, suggesting a background of approximately that magnitude. When this background is subtracted and the resulting data corrected to 1945, the measured 63 Ni in copper samples from Hiroshima are in good agreement with DS02 sample-specific calculations. Comparisons with DS86 calculations also show good agreement except at the Bank of Japan. The difference at that distance is significant when compared with DS86 calculations. (J.P.N.)

Quality policy on radiocarbon measurement at the JAEA-Mutsu AMS

International Nuclear Information System (INIS)

Otosaka, Shigeyoshi; Amano, Hikaru; Kabuto, Shoji; Kinoshita, Naoki; Tanaka, Takayuki

2008-01-01

Since April 2006, a common use of the JAEA-Mutsu AMS has been available for researchers inside/outside JAEA. Before the receiving 14 C data to the researchers, we calculate pMC (per cent modern carbon) value and accuracy/precision of the measurement is confirmed according to the JAEA-Mutsu's quality policy. In this paper, an outline of the quality policy is described. (author)

Precise measurement of the neutron capture reaction 54Fe(n,γ)55Fe via AMS

International Nuclear Information System (INIS)

Wallner, A; Buczak, K; Forstner, O; Golser, R; Kutschera, W; Lederer, C; Priller, A; Steier, P; Belgya, T; Szentmiklosi, L; Bichler, M; Coquard, L; Dillmann, I; Kaeppeler, F; Mengoni, A; Reifarth, R

2010-01-01

The measurement of cross sections relevant to nuclear astrophysics has become one main research topic at the VERA (Vienna Environmental Research Accelerator) facility. The technique applied, accelerator mass spectrometry (AMS), offers excellent sensitivity for the detection of long-lived radionuclides through ultra-low isotope ratio measurements. We discuss the potential and preliminary results of ongoing precision measurements of neutron-capture cross sections of 54 Fe. Such measurements might help to clarify the recently found discrepancy of s-process nucleosynthesis at lower-mass nuclei (A 55 Fe (t 1/2 = 2.72 yr) was analyzed using AMS. At VERA, detection of 55 Fe was developed with a reproducibility of about 1%, which makes the 54 Fe(n,γ) 55 Fe reaction a precise and unique laboratory measurement, which can serve as a reference to complementary techniques. In this regard a new 55 Fe standard for AMS measurements was produced. The final cross-section data are expected to be accurate to better than 3%. We report a preliminary, however, already significantly improved thermal neutron cross section value of (2.32 ± 0.10) barn, and a value of (6.3 ± 0.6) mbarn for E n = (520 ± 50) keV.

Geochemical association of Pu and Am in selected host-phases of contaminated soils from the UK and their susceptibility to chemical and microbiological leaching

International Nuclear Information System (INIS)

Kimber, Richard L.; Corkhill, Claire L.; Amos, Sean; Livens, Francis R.; Lloyd, Jonathan R.

2015-01-01

Understanding the biogeochemical behaviour and potential mobility of actinides in soils and groundwater is vital for developing remediation and management strategies for radionuclide-contaminated land. Pu is known to have a high Kd in soils and sediments, however remobilization of low concentrations of Pu remains a concern. Here, some of the physicochemical properties of Pu and the co-contaminant, Am, are investigated in contaminated soils from Aldermaston, Berkshire, UK, and the Esk Estuary, Cumbria, UK, to determine their potential mobility. Sequential extraction techniques were used to examine the host-phases of the actinides in these soils and their susceptibility to microbiological leaching was investigated using acidophilic sulphur-oxidising bacteria. Sequential extractions found the majority of 239,240 Pu associated with the highly refractory residual phase in both the Aldermaston (63.8–85.5 %) and Esk Estuary (91.9–94.5%) soils. The 241 Am was distributed across multiple phases including the reducible oxide (26.1–40.0%), organic (45.6–63.6%) and residual fractions (1.9–11.1%). Plutonium proved largely resistant to leaching from microbially-produced sulphuric acid, with a maximum 0.18% leached into solution, although up to 12.5% of the 241 Am was leached under the same conditions. If Pu was present as distinct oxide particles in the soil, then 241 Am, a decay product of Pu, would be expected to be physically retained in the particle. The differences in geochemical association and bioleachability of the two actinides suggest that this is not the case and hence, that significant Pu is not present as distinct particles. These data suggest the majority of Pu in the contaminated soils studied is highly recalcitrant to geochemical changes and is likely to remain immobile over significant time periods, even when challenged with aggressive “bioleaching” bacteria. - Highlights: • Pu in the contaminated soils is associated with the recalcitrant

Magnetic susceptibility measurements of boring cores obtained from regional hydrological study project

International Nuclear Information System (INIS)

Hasegawa, Ken

2010-02-01

We measured the magnetic susceptibility of boring cores obtained from the Regional Hydrological Study Project to interpret the aeromagnetic survey data which was carried out in Tono area with about 40km square surrounding Tono Geoscience Center. The result of measurements indicates that the magnetic susceptibility of the Toki Granite is not distributed uniformly and the maximum value becomes two orders in magnitude larger than its minimum value. (author)

Quantitative measurements of brain iron deposition in cirrhotic patients using susceptibility mapping.

Science.gov (United States)

Xia, Shuang; Zheng, Gang; Shen, Wen; Liu, Saifeng; Zhang, Long Jiang; Haacke, E Mark; Lu, Guang Ming

2015-03-01

Susceptibility-weighted imaging (SWI) has been used to detect micro-bleeds and iron deposits in the brain. However, no reports have been published on the application of SWI in studying iron changes in the brain of cirrhotic patients. To compare the susceptibility of different brain structures in cirrhotic patients with that in healthy controls and to evaluate susceptibility as a potential biomarker and correlate the measured susceptibility and cadaveric brain iron concentration for a variety of brain structures. Forty-three cirrhotic patients (27 men, 16 women; mean age, 50 ± 9 years) and 34 age- and sex-matched healthy controls (22 men, 12 women; mean age, 47 ± 7 years) were included in this retrospective study. Susceptibility was measured in the frontal white matter, basal ganglia, midbrain, and dentate nucleus and compared with results gathered from two postmortem brain studies. Correlation between susceptibility and clinical biomarkers and neuropsychiatric tests scores was calculated. In cirrhotic patients, the susceptibility of left frontal white matter, bilateral caudate head, and right substantia nigra was higher than that in healthy controls (P brain study (r = 0.835, P = 0.01) in eight deep grey matter structures and another in five brain structures (r = 0.900, P = 0.03). The susceptibility of right caudate head (r = 0.402) and left caudate head (r = 0.408) correlated with neuropsychological test scores (both P brain regions appears to reflect neurocognitive changes. © The Foundation Acta Radiologica 2014 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

The use of magnetic susceptibility measurements to determine ...

African Journals Online (AJOL)

This research work presents a study on the application of magnetic susceptibility measurements and geochemical analysis for mapping or assessing heavy metal pollution in the agricultural soil in road proximity. The research work was also done to check any runoff of heavy metals pollution to the Owabi dam which serves ...

Tritium AMS for biomedical applications

International Nuclear Information System (INIS)

Roberts, M.L.; Velsko, C.; Turteltaub, K.W.

1993-08-01

We are developing 3 H-AMS to measure 3 H activity of mg-sized biological samples. LLNL has already successfully applied 14 C AMS to a variety of problems in the area of biomedical research. Development of 3 H AMS would greatly complement these studies. The ability to perform 3 H AMS measurements at sensitivities equivalent to those obtained for 14 C will allow us to perform experiments using compounds that are not readily available in 14 C-tagged form. A 3 H capability would also allow us to perform unique double-labeling experiments in which we learn the fate, distribution, and metabolism of separate fractions of biological compounds

Measurement of Am-242 fission yields at the Lohengrin spectrometer; improvement and Benchmarking of the semi-empirical code GEF

International Nuclear Information System (INIS)

Amouroux, Charlotte

2014-01-01

The study of fission yields has a major impact on the characterization and understanding of the fission process and is mandatory for reactor applications. While the yields are known for the major actinides (U-235, Pu-239) in the thermal neutron-induced fission, only few measurements were performed on Am-242. Moreover, the two main data libraries do not agree among each other on the light peak. Am-241 and Am-242 are nuclei of interest for the MOX-fuel reactors and for the reduction of nuclear waste radiotoxicity using transmutation reactions. Thus, a campaign of precise measurement of the fission mass yields from the reaction Am-241(2n,f) was performed at the Lohengrin mass spectrometer (ILL, France) for both the light and the heavy peak. Forty-one masses were measured. Moreover, the measurement of the isotopic fission yields on the heavy peak by gamma-ray spectrometry led to the extraction of 20 independent isotopic yields. Our measurement was also meant to determine whether there is a difference in fission yields between the Am-242 isomeric state and its ground state as it exists in fission cross sections. The experimental method used to answer this question is based on the measurement a set of fission mass yields as a function of the ratio of Am-242gs to Am-242m fission rate. Results show that the mass yields are independent of the fission rate ratio. A future experimental campaign is proposed to observe a possible influence on the isomeric yields. The theoretical models are nowadays unable to predict the fission yields with enough accuracy and therefore we have to rely on experimental data and phenomenological models. The accuracy of the predictions of the semi empirical GEF fission model predictions makes it a useful tool for evaluation. This thesis also presents the physical content and part of the development of this model. Validation of the kinetic energy distributions, isomeric yields and fission yields predictions was performed. The extension of the GEF

Continuous Real-time Measurements of Vertical Distribution of Magnetic Susceptibility In Soils

Science.gov (United States)

Petrovsky, E.; Hulka, Z.; Kapicka, A.; Magprox Team

Measurements of top-soil magnetic susceptibility are used in approximative outlining polluted areas. However, one of the serious limitations of the method is discrimina- tion between top-soil layers enhanced by atmospherically deposited anthropogenic particles from those dominated by natural particles migrating from magnetically-rich basement rocks. For this purpose, measurements of vertical distribution of magnetic susceptibility along soil profiles is one of the most effective ways in estimating the effect of lithogenic contribution. Up to now, in most cases soil cores have to be mea- sured in laboratory. This method is quite time consuming and does not allow flexible decision about the suitability of the measured site for surface magnetic mapping. In our contribution we will present a new device enabling continuous real-time measure- ments of vertical distribution of magnetic susceptibility directly in field, performed in holes after soil coring. The method is fast, yielding smooth curves (6 data points per 1 mm dept), at least as sensitive as laboratory methods available until now, and at- tached notebook enables direct, on-line control of the lithogenic versus anthropogenic contributions.

Aerial Measuring System (AMS)/ Israel Atomic Energy Commission (IAEC) Joint Comparison Study

International Nuclear Information System (INIS)

Halevy, I.; Dadon, S.; Sheinfeld, M.; Broide, A.; Rofe, S.; Yaar, I.; Wasiolek, P.

2014-01-01

In support of the U.S. Department of Energy (DOE) International Emergency Management and Cooperation (IEMC/NA-46) Program, the comparison of the U.S. and Israeli Aerial Measuring Systems (AMS) study was proposed and accepted. The study, organized by the DOE/National Nuclear Security Administration (NNSA) Remote Sensing Laboratory (RSL), involved the DOE/NNSA Aerial Measuring System Project based at the RSL and operated under a contractor agreement by National Security Technologies, LLC (NSTec), and the Israel Atomic Energy Commission (IAEC) Aerial Measuring System. The operational comparison was conducted at RSL-Nellis in Las Vegas, Nevada, during week of June 24–27, 2013. The Israeli system, Air RAM 2000 (figure 1, down), was shipped to RSL-Nellis and mounted together with the DOE Spectral Advanced Radiological Computer System, Model A (SPARCS-A, figure 1 up) on U.S. DOE Bell-412 helicopter for a series of aerial comparison measurements at local test ranges, including the Desert Rock Airport and Area 3 at the Nevada National Security Site (NNSS). A four-person Israeli team from the IAEC, Nuclear Research Center – Negev (NRCN) supported the activity. The main objective of this joint comparison was use the DOE/RSL Bell-412 helicopter aerial platform, perform the comparison study of measuring techniques and radiation acquisition systems utilized for emergency response by IEAC and NNSA AMS

The LLNL AMS facility

International Nuclear Information System (INIS)

Roberts, M.L.; Bench, G.S.; Brown, T.A.

1996-05-01

The AMS facility at Lawrence Livermore National Laboratory (LLNL) routinely measures the isotopes 3 H, 7 Be, 10 Be, 14 C, 26 Al, 36 Cl, 41 Ca, 59,63 Ni, and 129 I. During the past two years, over 30,000 research samples have been measured. Of these samples, approximately 30% were for 14 C bioscience tracer studies, 45% were 14 C samples for archaeology and the geosciences, and the other isotopes constitute the remaining 25%. During the past two years at LLNL, a significant amount of work has gone into the development of the Projectile X-ray AMS (PXAMS) technique. PXAMS uses induced characteristic x-rays to discriminate against competing atomic isobars. PXAMS has been most fully developed for 63 Ni but shows promise for the measurement of several other long lived isotopes. During the past year LLNL has also conducted an 129 I interlaboratory comparison exercise. Recent hardware changes at the LLNL AMS facility include the installation and testing of a new thermal emission ion source, a new multianode gas ionization detector for general AMS use, re-alignment of the vacuum tank of the first of the two magnets that make up the high energy spectrometer, and a new cryo-vacuum system for the AMS ion source. In addition, they have begun design studies and carried out tests for a new high-resolution injector and a new beamline for heavy element AMS

Measurement and analysis of the $^{243}$Am neutron capture cross section at the n_TOF facility at CERN

CERN Document Server

Mendoza, E; Guerrero, C; Berthoumieux, E; Abbondanno, U; Aerts, G; Alvarez-Velarde, F; Andriamonje, S; Andrzejewski, J; Assimakopoulos, P; Audouin, L; Badurek, G; Balibrea, J; Baumann, P; Becvar, F; Belloni, F; Calvino, F; Calviani, M; Capote, R; Carrapico, C; Carrillo de Albornoz, A; Cennini, P; Chepel, V; Chiaveri, E; Colonna, N; Cortes, G; Couture, A; Cox, J; Dahlfors, M; David, S; Dillmann, I; Dolfini, R; Domingo-Pardo, C; Dridi, W; Duran, I; Eleftheriadis, C; Ferrant†, L; Ferrari, A; Ferreira-Marques, R; Fitzpatrick, L; Frais-Koelbl, H; Fujii, K; Furman, W; Goncalves, I; Gonz alez-Romero, E; Goverdovski, A; Gramegna, F; Griesmayer, E; Gunsing, F; Haas, B; Haight, R; Heil, M; Herrera-Martinez, A; Igashira, M; Isaev, S; Jericha, E; Kappeler, F; Kadi, Y; Karadimos, D; Karamanis, D; Ketlerov, V; Kerveno, M; Koehler, P; Konovalov, V; Kossionides, E; Krticka, M; Lampoudis, C; Leeb, H; Lindote, A; Lopes, I; Lossito, R; Lozano, M; Lukic, S; Marganiec, J; Marques, L; Marrone, S; Martınez, T; Massimi, C; Mastinu, P; Mengoni, A; Milazzo, P M; Moreau, C; Mosconi, M; Neves, F; Oberhummer, H; O’Brien, S; Oshima, M; Pancin, J; Papachristodoulou, C; Papadopoulos, C; Paradela, C; Patronis, N; Pavlik, A; Pavlopoulos, P; Perrot, L; Pigni, M T; Plag, R; Plompen, A; Plukis, A; Poch, A; Praena, J; Pretel, C; Quesada, J; Rauscher, T; Reifarth, R; Rosetti, M; Rubbia, C; Rudolf, G; Rullhusen, P; Salgado, J; Santos, C; Sarchiapone, L; Savvidis, I; Stephan, C; Tagliente, G; Tain, J L; Tassan-Got, L; Tavora, L; Terlizzi, R; Vannini, G; Vaz, P; Ventura, A; Villamarin, D; Vicente, M C; Vlachoudis, V; Vlastou, R; Voss, F; Walter, S; Wendler, H; Wiescher, M; Wisshak, K

2014-01-01

Background:The design of new nuclear reactors and transmutation devices requires to reduce the present neutron cross section uncertainties of minor actinides. Purpose: Reduce the $^{243}$Am(n,$\\gamma$) cross section uncertainty. Method: The $^{243}$Am(n,$\\gamma$) cross section has been measured at the n_TOF facility at CERN with a BaF$_{2}$ Total Absorption Calorimeter, in the energy range between 0.7 eV and 2.5 keV. Results: The $^{243}$Am(n,$\\gamma$) cross section has been successfully measured in the mentioned energy range. The resolved resonance region has been extended from 250 eV up to 400 eV. In the unresolved resonance region our results are compatible with one of the two incompatible capture data sets available below 2.5 keV. The data available in EXFOR and in the literature has been used to perform a simple analysis above 2.5 keV. Conclusions: The results of this measurement contribute to reduce the $^{243}$Am(n,$\\gamma$) cross section uncertainty and suggest that this cross section is underestimate...

AMS analyses at ANSTO

Energy Technology Data Exchange (ETDEWEB)

Lawson, E.M. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia). Physics Division

1998-03-01

The major use of ANTARES is Accelerator Mass Spectrometry (AMS) with {sup 14}C being the most commonly analysed radioisotope - presently about 35 % of the available beam time on ANTARES is used for {sup 14}C measurements. The accelerator measurements are supported by, and dependent on, a strong sample preparation section. The ANTARES AMS facility supports a wide range of investigations into fields such as global climate change, ice cores, oceanography, dendrochronology, anthropology, and classical and Australian archaeology. Described here are some examples of the ways in which AMS has been applied to support research into the archaeology, prehistory and culture of this continent`s indigenous Aboriginal peoples. (author)

AMS analyses at ANSTO

International Nuclear Information System (INIS)

Lawson, E.M.

1998-01-01

The major use of ANTARES is Accelerator Mass Spectrometry (AMS) with 14 C being the most commonly analysed radioisotope - presently about 35 % of the available beam time on ANTARES is used for 14 C measurements. The accelerator measurements are supported by, and dependent on, a strong sample preparation section. The ANTARES AMS facility supports a wide range of investigations into fields such as global climate change, ice cores, oceanography, dendrochronology, anthropology, and classical and Australian archaeology. Described here are some examples of the ways in which AMS has been applied to support research into the archaeology, prehistory and culture of this continent's indigenous Aboriginal peoples. (author)

Radiocarbon measurements of small gaseous samples at CologneAMS

Science.gov (United States)

Stolz, A.; Dewald, A.; Altenkirch, R.; Herb, S.; Heinze, S.; Schiffer, M.; Feuerstein, C.; Müller-Gatermann, C.; Wotte, A.; Rethemeyer, J.; Dunai, T.

2017-09-01

A second SO-110 B (Arnold et al., 2010) ion source was installed at the 6 MV CologneAMS for the measurement of gaseous samples. For the gas supply a dedicated device from Ionplus AG was connected to the ion source. Special effort was devoted to determine optimized operation parameters for the ion source, which give a high carbon current output and a high 14C- yield. The latter is essential in cases when only small samples are available. Additionally a modified immersion lens and modified target pieces were tested and the target position was optimized.

Automatic magnetic susceptibility measurements between 4 K and 1200 K

International Nuclear Information System (INIS)

Raphael, G.

1969-01-01

We give a detailed description of a Faraday magnetic susceptibility balance which operates from 4 K to 1200 K. Some preliminary results on platinum and tantalum illustrate the precision and the sensitivity of the measurements. The apparatus has been designed for measurements on the plutonium compounds which present severe health hazards. (author) [fr

Complex Susceptibility Measurement Using Multi-frequency Slingram EMI Instrument

OpenAIRE

Simon , François Xavier; Tabbagh , Alain; Thiesson , Julien; Donati , J.C.; Sarris , A.

2014-01-01

International audience; Complex magnetic susceptibility is a well-known property both theoretically and experimentally. To achieve this measurement, different ways have been tested, like TDEM or multi-frequential measurement on soil sample. In this study we carry out the measurements by the use of a multi-frequential EMI Slingram instrument to collect data quickly and in-situ. The use of multi-frequency data is also a way to correct effects of the conductivity on the in-phase component and ef...

AMS ready for launch

CERN Multimedia

Katarina Anthony

2011-01-01

On 29 April, the Alpha Magnetic Spectrometer (AMS) will complete its long expedition to the International Space Station on board the space shuttle Endeavour. The Endeavour is set to lift off from NASA’s Kennedy Space Station at 15:47 EST (21:47 CET).   Samuel Ting, principal investigator for the AMS project, and Rolf Heuer, CERN Director-General, visit the Kennedy Space Centre before the AMS launch.  Courtesy of NASA and Kennedy Space Center. AMS is a CERN recognised experiment, created by an internal collaboration of 56 institutes. It will be the first large magnetic spectrometer to be used in space, and has been designed to function as an external module on the ISS. AMS will measure cosmic rays without atmospheric interference, allowing researchers on the ground to continue their search for dark matter and antimatter in the Universe. Data collected by AMS will be analysed in CERN’s new AMS Control Centre in Building 946 (due for completion in June 2011). The End...

Measurement of thermal neutron cross section for {sup 241}Am(n,f) reaction

Energy Technology Data Exchange (ETDEWEB)

Kobayashi, Katsuhei; Yamamoto, Shuji; Fujita, Yoshiaki [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst.; Miyoshi, Mitsuharu; Kimura, Itsuro; Kanno, Ikuo; Shinohara, Nobuo

1997-03-01

Making use of a standard neutron spectrum field with a pure Maxwellian distribution, the thermal neutron cross section for the {sup 241}Am(n,f) reaction has been measured relative to the reference value of 586.2b for the {sup 235U}(n,f) reaction. For the present measurement, electrodeposited layers of {sup 241}Am and {sup 235}U have been employed as back-to-back type double fission chambers. The present result at neutron energy of 0.0253 eV is 3.15 {+-} 0.097b. The ENDF/B-VI data is in good agreement with the present value, while the JENDL-3.2 data is lower by 4.2%. The evaluated data in JEF-2.2 and by Mughabghab are higher by 0.9% and 1.6%, respectively than the present result. The ratios of the earlier experimental data to the present value are distributed between 0.89 and 1.02. (author)

Method for the measurement of susceptibility to decubitus ulcer formation.

Science.gov (United States)

Meijer, J H; Schut, G L; Ribbe, M W; Goovaerts, H G; Nieuwenhuys, R; Reulen, J P; Schneider, H

1989-09-01

A method for measuring the susceptibility of a patient to develop decubitus ulcers is described and initially evaluated. It is based on an indirect, noninvasive measurement of the transient regional blood flow response after a test pressure load which simulates the external stimulus for pressure-sore formation. This method was developed to determine the individual risk of a patient and to study the subfactors which contribute to the susceptibility. This would also offer the possibility of evaluating the effect of preventive treatment aimed at reducing the susceptibility. The method was found to discriminate between preselected elderly patients at risk on the one hand, and non-risk patients and healthy young adults on the other hand. No differences in blood flow responses were found between the non-risk elderly patients and the healthy young adults. This suggests that age per se is not a factor in the formation of pressure sores. In the risk group the recovery time after pressure relief was found to be three times as long as the duration of the pressure exercise. This indicates that the recovery time after pressure exercise may be as important as the period of pressure exercise in deducing the risk of developing decubitus ulcers.

Neutron calibration facility with an Am-Be source for pulse shape discrimination measurement of CsI(Tl) crystals

International Nuclear Information System (INIS)

Lee, H.S.; Bhang, H.; Choi, J.H.; Choi, S.; Joo, H.W.; Kim, G.B.; Kim, K.W.; Kim, S.C.; Kim, S.K.; Lee, J.H.; Lee, J.K.; Myung, S.S.; Hahn, I.S.; Jeon, E.J.; Kang, W.G.; Kim, Y.D.; Kim, Y.H.; Li, J.; Kim, H.J.; Leonard, D.S.

2014-01-01

We constructed a neutron calibration facility based on a 300-mCi Am-Be source in conjunction with a search for weakly interacting massive particle candidates for dark matter. The facility is used to study the response of CsI(Tl) crystals to nuclear recoils induced by neutrons from the Am-Be source and comparing them with the response to electron recoils produced by Compton scattering of 662-keV γ-rays from a 137 Cs source. The measured results on pulse shape discrimination (PSD) between nuclear- and electron-recoil events are quantified in terms of quality factors. A comparison with our previous result from a neutron generator demonstrate the feasibility of performing calibrations of PSD measurements using neutrons from a Am-Be source

The Slab Method to Measure the Topological Susceptibility

CERN Document Server

Bietenholz, Wolfgang; de Forcrand, Philippe; Dromard, Arthur; Gerber, Urs

2016-10-11

In simulations of a model with topological sectors, algorithms which proceed in small update steps tend to get stuck in one sector, especially on fine lattices. This distorts the numerical results, in particular it is not straightforward to measure the topological susceptibility chi_t. We test a method to measure chi_t even if configurations from only one sector are available. It is based on the topological charges in sub-volumes, which we denote as "slabs". This enables the evaluation of chi_t, as we demonstrate with numerical results for non-linear sigma-models and for 2-flavour QCD.

Introduction to the AMS Experiment

CERN Multimedia

CERN. Geneva

2015-01-01

Following the pioneering experiments (ATIC, BESS, CREAM, HEAT, PAMELA, …), using a magnetic spectrometer (AMS) on ISS is a unique way to provide precision long term measurements of primordial high energy charged cosmic rays. AMS was installed on the Station in May 2011. Up to now, 60 billion events have been collected. 40 billion events have been partially analysed. AMS is scheduled to be on the Station until at least 2024. By then AMS will have collected close to 200 billion events. The detector properties and the analysis methods will be introduced.

Initial Results of an Intercomparison of AMS-Based Atmospheric 14CO2 Measurements

NARCIS (Netherlands)

Miller, John; Lehman, Scott; Wolak, Chad; Turnbull, Jocelyn; Dunn, Gregory; Graven, Heather; Keeling, Ralph; Meijer, Harro A. J.; Aerts-Bijma, Anita Th; Palstra, Sanne W. L.; Smith, Andrew M.; Allison, Colin; Southon, John; Xu, Xiaomei; Nakazawa, Takakiyo; Aoki, Shuji; Nakamura, Toshio; Guilderson, Thomas; LaFranchi, Brian; Mukai, Hitoshi; Terao, Yukio; Uchida, Masao; Kondo, Miyuki

2013-01-01

This article presents results from the first 3 rounds of an international intercomparison of measurements of Delta(CO2)-C-14 in liter-scale samples of whole air by groups using accelerator mass spectrometry (AMS). The ultimate goal of the intercomparison is to allow the merging of Delta(CO2)-C-14

Comparison Of ²⁵²Cf Time Correlated Induced Fisssion With AmLi Induced Fission On Fresh MTR Research Reactor Fuel

Energy Technology Data Exchange (ETDEWEB)

Joshi, Jay Prakash [Los Alamos National Laboratory

2017-03-30

The effective application of international safeguards to research reactors requires verification of spent fuel as well as fresh fuel. To accomplish this goal various nondestructive and destructive assay techniques have been developed in the US and around the world. The Advanced Experimental Fuel Counter (AEFC) is a nondestructive assay (NDA) system developed at Los Alamos National Laboratory (LANL) combining both neutron and gamma measurement capabilities. Since spent fuel assemblies are stored in water, the system was designed to be watertight to facilitate underwater measurements by inspectors. The AEFC is comprised of six ³He detectors as well as a shielded and collimated ion chamber. The ³He detectors are used for active and passive neutron coincidence counting while the ion chamber is used for gross gamma counting. Active coincidence measurement data is used to measure residual fissile mass, whereas the passive coincidence measurement data along with passive gamma measurement can provide information about burnup, cooling time, and initial enrichment. In the past, most of the active interrogation systems along with the AEFC used an AmLi neutron interrogation source. Owing to the difficulty in obtaining an AmLi source, a ²⁵²Cf spontaneous fission (SF) source was used during a 2014 field trail in Uzbekistan as an alternative. In this study, experiments were performed to calibrate the AEFC instrument and compare use of the ²⁵²Cf spontaneous fission source and the AmLi (α,n) neutron emission source. The ²⁵²Cf source spontaneously emits bursts of time-correlated prompt fission neutrons that thermalize in the water and induce fission in the fuel assembly. The induced fission (IF) neutrons are also time correlated resulting in more correlated neutron detections inside the ³He detector, which helps reduce the statistical errors in doubles when using the ²⁵²Cf interrogation source instead of

Cosmic-ray positron fraction measurement from 1 to 30 GeV with AMS-01

CERN Document Server

Aguilar, M; Allaby, James V; Alpat, B; Ambrosi, G; Anderhub, H; Ao, L; Arefev, A; Azzarello, P; Baldini, L; Basile, M; Barancourt, D; Barão, F; Barbier, G; Barreira, G; Battiston, R; Becker, R; Becker, U; Bellagamba, L; Bene, P; Berdugo, J; Berges, P; Bertucci, B; Biland, A; Blasko, S; Bölla, G; Boschini, M; Bourquin, M; Brocco, L; Bruni, G; Buénerd, M; Burger, J D; Burger, W J; Cai, X D; Camps, C; Cannarsa, P; Capell, M; Cardano, F; Casadei, D; Casaus, J; Castellini, G; Chang, Y H; Chen, H F; Chen, H S; Chen, Z G; Chernoplekov, N A; Tzi Hong Chiueh; Cho, K; Choi, M J; Choi, Y Y; Cindolo, F; Commichau, V; Contin, A; Cortina, E; Cristinziani, M; Dai, T S; Delgado, C; Difalco, S; Djambazov, L; D'Antone, I; Dong, Z R; Emonet, P; Engelberg, J; Eppling, F J; Eronen, T; Esposito, G; Extermann, P; Favier, Jean; Fiandrini, E; Fisher, P H; Flügge, G; Fouque, N; Galaktionov, Yu; Gast, H; Gervasi, M; Giusti, P; Grandi, D; Grimm, O; Gu, W Q; Hangarter, K; Hasan, A; Hermel, V; Hofer, H; Hungerford, W; Jongmanns, M; Karlamaa, K; Karpinski, W; Kenney, G; Kim, D H; Kim, G N; Kim, K S; Kim, M Y; Klimentov, A; Kossakowski, R; Kounine, A; Koutsenko, V F; Kraeber, M; Laborie, G; Laitinen, T; Lamanna, G; Lanciotti, E; Laurenti, G; Lebedev, A; Lechanoine-Leluc, C; Lee, M W; Lee, S C; Levi, G; Liu, C L; Liu, H T; Lu, G; Lü, Y S; Lübelsmeyer, K; Luckey, D; Lustermann, W; Maña, C; Margotti, A; Mayet, F; McNeil, R R; Meillon, B; Menichelli, M; Mihul, A; Mujunen, A; Oliva, A; Olzem, J; Palmonari, F; Park, H B; Park, W H; Pauluzzi, M; Pauss, F; Perrin, E; Pesci, A; Pevsner, A; Pilo, F; Pimenta, M; Plyaskin, V; Pozhidaev, V; Pohl, M; Produit, N; Rancoita, P G; Rapin, D; Raupach, F; Ren, D; Ren, Z; Ribordy, M; Richeux, J P; Riihonen, E; Ritakari, J; Ro, S; Röser, U; Rossin, C; Sagdeev, R; Santos, D; Sartorelli, G; Sbarra, C; Schael, S; Schultzvon Dratzig, A; Schwering, G; Seo, E S; Shin, J W; Shoumilov, E; Shoutko, V; Siedenburg, T; Siedling, R; Son, D; Song, T; Spinella, F; Steuer, M; Sun, G S; Suter, H; Tang, X W; Ting, Samuel C C; Ting, S M; Tornikoski, M; Torsti, J; Trumper, J; Ulbricht, J; Urpo, S; Valtonen, E; Vandenhirtz, J; Velikhov, E P; Verlaat, B; Vetlitskii, I; Vezzu, F; Vialle, J P; Viertel, G; Vite, D; Von Gunten, H; Waldmeier-Wicki, S; Wallraff, W; Wang, B C; Wang, J Z; Wiik, K; Williams, C; Wu, S X; Xia, P C; Xu, S; Yan, J L; Yan, L G; Yang, C G; Yang, J; Yang, M; Ye, S W; Xu, Z Z; Zhang, H Y; Zhang, Z P; Zhao, D X; Zhou, Y; Zhu, G Y; Zhu, W Z; Zhuang, H L; Zichichi, A; Zimmermann, B; Zuccon, P

2007-01-01

A measurement of the cosmic ray positron fraction e+/(e+ + e-) in the energy range of 1-30 GeV is presented. The measurement is based on data taken by the AMS-01 experiment during its 10 day Space Shuttle flight in June 1998. A proton background suppression on the order of 10^6 is reached by identifying converted bremsstrahlung photons emitted from positrons.

Cosmic-ray positron fraction measurement from 1 to 30 GeV with AMS-01

International Nuclear Information System (INIS)

Aguilar, M.; Alcaraz, J.; Allaby, J.

2007-01-01

A measurement of the cosmic ray positron fraction e + /(e + +e - ) in the energy range of 1-30 GeV is presented. The measurement is based on data taken by the AMS-01 experiment during its 10 day Space Shuttle flight in June 1998. A proton background suppression on the order of 10 6 is reached by identifying converted bremsstrahlung photons emitted from positrons

Evaluation of neutron nuclear data for 241Am and 243Am

International Nuclear Information System (INIS)

Kikuchi, Yasuyuki

1982-08-01

Neutron nuclear data of 241 Am and 243 Am were evaluated for JENDL-2. Evaluated quantities are the total, elastic and inelastic scattering, fission, capture, (n,2n), (n,3n) and (n,4n) reaction cross sections, the resolved and unresolved resonance parameters, the angular or energy distribution of the emitted neutrons, and the average number of neutrons emitted per fission. The fission cross section was evaluated on the basis of newly measured data, and lower values than JENDL-1 were given in the subthreshold energy region. The reliability of the calculation parameters are also much improved, because experimental data became available for the total and capture cross sections of 241 Am in the high energy region. (author)

The SUERC AMS laboratory after 3 years

International Nuclear Information System (INIS)

Freeman, Stewart; Bishop, Paul; Bryant, Charlotte; Cook, Gordon; Dougans, Drew; Ertunc, Tanya; Fallick, Anthony; Ganeshram, Raja; Maden, Colin; Naysmith, Philip; Schnabel, Christoph; Scott, Marian; Summerfield, Michael; Xu Sheng

2007-01-01

The new SUERC AMS Laboratory was described at AMS-9. Since then there have been technological developments, added and improved analysis capability, the formation of additional complementary groups, the purchase of another instrument, and many samples measured. Be, C, Al, Cl, Ca and I-AMS are established with measured species changing weekly. Full-terminal potential running is now routine and 5 MV is proving sufficient for all species. Ion detection and evaluation has also been improved by the use of even thinner detector windows as necessary and a more powerful on-line data analysis system. Routine radiocarbon measurement is to 4 per mille reproducibility at middling current and graphite samples of as little as 100 μg C can be accommodated. Even smaller samples can be measured as CO 2 using He carrier in the gas capable ion source. Two new sample preparation laboratories at SUERC are the NERC Cosmogenic Isotope Analysis Facility and the SUERC/University of Glasgow Centre for Geosciences Cosmogenic Nuclide Laboratory. In particular these benefit from competitive Be-AMS and Cl-AMS performance

Bioanalysis works in the IAA AMS facility: Comparison of AMS analytical method with LSC method in human mass balance study

International Nuclear Information System (INIS)

Miyaoka, Teiji; Isono, Yoshimi; Setani, Kaoru; Sakai, Kumiko; Yamada, Ichimaro; Sato, Yoshiaki; Gunji, Shinobu; Matsui, Takao

2007-01-01

Institute of Accelerator Analysis Ltd. (IAA) is the first Contract Research Organization in Japan providing Accelerator Mass Spectrometry (AMS) analysis services for carbon dating and bioanalysis works. The 3 MV AMS machines are maintained by validated analysis methods using multiple control compounds. It is confirmed that these AMS systems have reliabilities and sensitivities enough for each objective. The graphitization of samples for bioanalysis is prepared by our own purification lines including the measurement of total carbon content in the sample automatically. In this paper, we present the use of AMS analysis in human mass balance and metabolism profiling studies with IAA 3 MV AMS, comparing results obtained from the same samples with liquid scintillation counting (LSC). Human samples such as plasma, urine and feces were obtained from four healthy volunteers orally administered a 14 C-labeled drug Y-700, a novel xanthine oxidase inhibitor, of which radioactivity was about 3 MBq (85 μCi). For AMS measurement, these samples were diluted 100-10,000-fold with pure-water or blank samples. The results indicated that AMS method had a good correlation with LSC method (e.g. plasma: r = 0.998, urine: r = 0.997, feces: r = 0.997), and that the drug recovery in the excreta exceeded 92%. The metabolite profiles of plasma, urine and feces obtained with HPLC-AMS corresponded to radio-HPLC results measured at much higher radioactivity level. These results revealed that AMS analysis at IAA is useful to measure 14 C-concentration in bioanalysis studies at very low radioactivity level

Disk-cylinder method for using NMR to measure magnetic susceptibility

International Nuclear Information System (INIS)

Burnham, A.K.

1978-01-01

The sphere-cylinder method of using nuclear magnetic resonance (NMR) to measure the magnetic susceptibility of diamagnetic and paramagnetic materials has been generalized to the disk-cylinder method. A two-fold increase in sensitivity was obtained. Accuracies of 0.1% of the diamagnetism of water should be readily obtainable

Measurement of the 243Am capture cross section at the n{sub T}OF facility; Medida de la sección eficaz de captura del 243Am en la instalación n{sub T}OF

Energy Technology Data Exchange (ETDEWEB)

Mendoza Cembranos, E.

2014-07-01

Nuclear data for minor actinides are necessary for improving the design and performance of advanced reactors and transmutation devices for the incineration of radioactive nuclear waste [Sal08, Gon09, Ali04, Ali06]. In particular, the 243Am isotope is relevant since it is the minor actinide which contributes more to the radiotoxicity of the nuclear waste between s3 03 and s3 04 years. In addition, the neutron capture in 243Am is the main gate to the creation of 244Cm and higher mass isotopes. The purpose of the this work is to provide experimental data on the 243Am(n, ) for improving the current evaluations. At present, there is no published neutron capture measurement of 243Am below 250 eV, and all the existing evaluations of the elastic and capture cross sections are based essentially on a single transmission measurement [Sim74]. Above 250 eV there are only a few capture measurements available [Wes85, Wis83], which show discrepancies that make them incompatible. Due to the lack of experimental data on 243Am the standard ENDF-6 format libraries present sizeable di rences between each other...(Author)

Validation of Am-241 measurement in ion chamber type smoke detector by using gamma spectrometry system

International Nuclear Information System (INIS)

Yii Mei Wo; Khairul Nizam Razali

2005-01-01

Smoke detectors are useful devices in modern days that able to save many lives. Even though, the use of ion chamber type smoke detector (usually contain Americium-241) was exempted in Malaysia, but the trading of this device was controlled by regulation, under the Atomic Energy Licensing Act (Act 304). The activity of the Am-241 can be measured by using the Gamma Spectrometry System since it was much easier, compared to Alpha Spectrometry System. To do so, the system was first need to be calibrated using the standard reference source to find the efficiency of the germanium detector. The method used for the measurement was first validated for several relevant parameters, which include specificity, precision (repeatability), bias (accuracy), linearity, working range, detection limit, robustness and ruggedness to ensure it was fit for the purpose. The measured Am-241 activity inside the smoke detector will be reported together with a reasonable expanded uncertainty arise from the measurement. (Author)

Critical mass calculations for 241Am, 242mAm and 243Am

International Nuclear Information System (INIS)

Dias, Hemanth; Tancock, Nigel; Clayton, Angela

2003-01-01

Criticality mass calculations are reported for 241 Am, 242m Am and 243 Am using the MONK and MCNP computer codes with the UKNDL, JEF-2.2, ENDF/B-VI and JENDL-3.2 nuclear data libraries. Results are reported for spheres of americium metal and dioxide in bare, water reflected and steel reflected systems. Comparison of results led to the identification of a serious inconsistency in the 241 Am ENDF/B-VI DICE library used by MONK - this demonstrates the importance of using different codes to verify critical mass calculations. The 241 Am critical mass estimates obtained using UKNDL and ENDF/B-VI show good agreement with experimentally inferred data, whilst both JEF-2.2 and JENDL-3.2 produce higher estimates of critical mass. The computed critical mass estimates for 242m Am obtained using ENDF/B-VI are lower than the results produced using the other nuclear data libraries - the ENDF/B-VI fission cross-section for 242m Am is significantly higher than the other evaluations in the fast region and is not supported by recent experimental data. There is wide variation in the computed 243 Am critical mass estimates suggesting that there is still considerable uncertainty in the 243 Am nuclear data. (author)

Method of magnetic susceptibility mapping of drilled cores. Experimental measurements for geologic structures determination

International Nuclear Information System (INIS)

Delrive, C.

1993-01-01

The evaluation of the safety of a deep geologic repository for dangerous materials requires the knowledge of the interstitial system of the surrounding host rock. A method is proposed for the determination of geologic structures (in particular fractures) from the magnetic susceptibility mapping of drilled cores. The feasibility of the method has been demonstrated using a SQUID magneto-gradient meter. A measurement tool using a new magnetic susceptibility captor and a testing bench have been developed. This tool allows the measurement of rocks with a magnetic susceptibility greater than 10 -5 SI units and can generate magnetic susceptibility maps with 4 x 4 mm 2 pixels. A magnetic visibility criterion has been defined which allows to foresee if a structure is visible or not. According to the measurements done, it is shown that any centimeter-scale structure with a sufficient magnetic contrast (20%) with respect to the matrix is visible. Therefore, the dip and the orientation of such structure can be determined with a 3 degree and a 5 degree precision, respectively. The position of the structure along the core axis is known with a 4 mm precision. On the other hand, about half of the magnetic contrasts observed do not correspond to the visual analyses and can be explained by very small variations of the mineralogic composition. This last point offers some interesting ways for future research using magnetic susceptibility mapping. (J.S.). 31 refs., 90 figs., 18 tabs., 2 photos., 6 appends

Status of recent utilization of JAEA AMS MUTSU

International Nuclear Information System (INIS)

Amano, Hikaru; Kabuto, Shoji; Kinoshita, Naoki

2008-01-01

Tandetron AMS was set up at the JAEA Mutsu in 1997. This AMS has been used for the determination of 14 C/ 12 C and 129 I/ 127 I. So far, 7075 samples have been measured for the 14 C-AMS, and 1317 samples have been measured for the 129 I-AMS until the end of September 2007. This AMS has adopted the open door policy which is periodic filing of applications and judgment for use twice a year, expecting broad usage including environmental issue and estimation of radioactive wastes for the general users from the spring of 2006. Eight external assignments have adopted in the first half of 2007, eleven external assignments have adopted in the latter half of 2007 at the JAEA AMS MUTSU. (author)

Present status of the JAEA-AMS-TONO. 2012

International Nuclear Information System (INIS)

Saito-Kokubu, Yoko; Matsubara, Akihiro; Ishimaru, Tsuneari; Hanaki, Tatsumi; Nishizawa, A.; Miyake, M.; Ohwaki, Y.; Nishio, T.; Tanaka, Takayuki

2013-01-01

The Tono Geoscience Center (TGC) of JAEA has been conducting research into deep underground environments for R and D program related to the geological disposal of High-Level Radioactive Waste. The AMS system of the TGC has routinely been used for 14 C-AMS since it started to be operated in 1998. In recent years, we have promoted the development of system technology for routine 10 Be-AMS. An inter-laboratory comparison of the 14 C-AMS was performed with the JAEA-AMS-MUTSU. The data of isotope ratios obtained with both AMS systems showed that there is no significant difference between them. In the development for the 10 Be-AMS, several test measurements have been performed by using standard samples. The results indicated fairly robust stability of data quality, which contributed to complete the development for routine 10 Be measurement. We are now in the stage of the development for routine 26 Al-AMS. (author)

Mechanism of formation of volcanic bombs: insights from a pilot study of anisotropy of magnetic susceptibility and preliminary assessment of analytical models

Science.gov (United States)

Cañón-Tapia, Edgardo

2017-07-01

Volcanic bombs and achneliths are a special type of pyroclastic fragments formed by mildly explosive volcanic eruptions. Models explaining the general shapes of those particles can be divided in two broad categories. The most popular envisages the acquisition of shapes of volcanic bombs as the result of the rush of air acting on a fluid clot during flight, and it includes many variants. The less commonly quoted model envisages their shapes as the result of forces acting at the moment of ejection of liquid from the magma pool in the conduit, experiencing an almost negligible modification through its travel through air. Quantitative evidence supporting either of those two models is limited. In this work, I explore the extent to which the anisotropy of magnetic susceptibility (AMS) might be useful in the study of mechanisms of formation of volcanic bombs by comparing measurements made on two spindle and two bread-crusted bombs. The results of this pilot study reveal that the degree of anisotropy of spindle bombs is larger, and their principal susceptibility axes are better clustered than on bread-crusted bombs. Also, the orientation of the principal susceptibility axes is consistent with two specific models (one of the in-flight variants and the general ejection model). Consequently, the reported AMS measurements, albeit limited in number, indicate that it is reasonable to focus attention on only two specific models to explain the acquisition of the shapes of volcanic bombs. Based on a parallel theoretical assessment of analytical models, a third alternative is outlined, envisaging volcanic bomb formation as a two-stage process that involves the bursting of large ( m) gas bubbles on the surface of a magma pond. The new model advanced here is also consistent with the reported AMS results, and constitutes a working hypothesis that should be tested by future studies richer in data. Fortunately, since this work also establishes that AMS can be used to determine magnetic

Measurements of Plutonium isotopes and the search for super-heavy elements via AMS

International Nuclear Information System (INIS)

Wallner, A.; Steier, P.; Golser, R.; Knie, K.; Kutschera, W.; Priller, A.; Hrnecek, E.; Jakopic, R.; Korschinek, G.

2006-01-01

Full text: Accelerator Mass Spectrometry (AMS) - being independent on the half-life of a radionuclide - provides a technique to determine isotope ratios with the highest sensitivity and allows the measurement of radionuclides over a wide dynamic range of concentration levels. A combination of AMS, Alpha Spectrometry and Liquid Scintillation Counting was used for the determination of the complete information on isotope ratios of Plutonium isotopes in different environmental reference samples (e.g. from the atolls of Mururoa and Fangataufa) and samples contaminated from nuclear reprocessing. Results for the isotopic ratios of the samples will be shown and the capabilities and detection limits achievable for determination of Pu will be discussed. The long-lived 244 Pu (t 1/2 = 80 Ma) and 247 Cm (t 1/2 = 15.6 Ma) have a very interesting application in astrophysics by detecting possible supernova-produced 244 Pu and 247 Cm in terrestrial archives. The expected extremely small concentrations of 244 Pu makes AMS the favorite method. The actual search for such long-lived extraterrestrial radionuclides and possible implications will be presented. The same method has also been explored for a pinprick-search of long-lived super-heavy elements in the mass region above Z=100. (author)

Magnetic hysteresis and complex susceptibility as measures of ac losses in a multifilamentary NbTi superconductor

International Nuclear Information System (INIS)

Goldfarb, R.B.; Clark, A.F.

1985-01-01

Magnetization and ac susceptibility of a standard NbTi superconductor were measured as a function of longitudinal dc magnetic field. The ac-field-amplitude and frequency dependences of the complex susceptibility are examined. The magnetization is related to the susceptibility by means of a theoretical derivation based on the field dependence of the critical current density. Hysteresis losses, obtained directly from dc hysteresis loops and derived theoretically from ac susceptibility and critical current density, were in reasonable agreement

Impact des politiques fiscales visant à améliorer la nutrition en ...

International Development Research Centre (IDRC) Digital Library (Canada)

améliorer la nutrition en Afrique du Sud. Prévention des maladies non transmissibles. (PMNT). PROFIL DE PROJET. Le programme Prévention des maladies non transmis- sibles (PMNT) soutient la production de nouvelles connaissances en vue d'inspirer des politiques et des pro- grammes peu coûteux mais susceptibles ...

Preliminary measurements on the new TOF system installed at the AMS beamline of INFN-LABEC

Energy Technology Data Exchange (ETDEWEB)

Palla, L., E-mail: palla@fi.infn.it [Dipartimento di Fisica, Università di Pisa, e INFN Sezione di Pisa (Italy); Castelli, L. [INFN Sezione di Firenze (Italy); Czelusniak, C. [INFN Sezione di Firenze (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze (Italy); Fedi, M.E. [INFN Sezione di Firenze (Italy); Giuntini, L. [INFN Sezione di Firenze (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze (Italy); Liccioli, L. [INFN Sezione di Firenze (Italy); Dipartimento di Chimica Ugo Schiff, Università di Firenze (Italy); Mandò, P.A. [INFN Sezione di Firenze (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze (Italy); Martini, M. [Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, e INFN Sezione di Milano Bicocca, Milano (Italy); Mazzinghi, A. [INFN Sezione di Firenze (Italy); Dipartimento di Fisica e Astronomia, Università di Firenze (Italy); Ruberto, C. [INFN Sezione di Firenze (Italy); Dipartimento di Chimica Ugo Schiff, Università di Firenze (Italy); Schiavulli, L. [Dipartimento di Fisica, Università di Bari, e INFN Sezione di Bari (Italy); Sibilia, E. [Dipartimento di Scienza dei Materiali, Università di Milano Bicocca, e INFN Sezione di Milano Bicocca, Milano (Italy); Taccetti, F. [INFN Sezione di Firenze (Italy)

2015-10-15

A high resolution time of flight (TOF) system has been developed at LABEC, the 3 MV Tandem accelerator laboratory in Florence, in order to improve the sensitivity of AMS measurements on carbon samples with ultra-low concentration and also to measure other isotopes, such as {sup 129}I. The system can be employed to detect and identify residual interfering particles originated from the break-up of molecular isobars. The set-up has been specifically designed for low energy heavy ions: it consists of two identical time pick-off stations, each made up of a thin conductive foil and a Micro-Channel Plate (MCP) multiplier. The beamline is also equipped with a silicon detector, installed downstream the stop TOF station. In this paper the design of the new system and the implemented readout electronics are presented. The tests performed on the single time pick-off station are reported: they show that the maximum contribution to the timing resolution given by both the intrinsic MCP resolution and the electronics is ⩽500 ps (FWHM). For these tests, single particle pulsed beams of 2–5 MeV protons and 10 MeV {sup 12}C{sup 3+} ions, to simulate typical AMS conditions, were used. The preliminary TOF and TOF-E (TOF-energy) measurements performed with carbon beams after the installation of the new system on the AMS beam line are also discussed. These measurements were performed using the foil–MCP as the start stage and a silicon detector as the stop stage. The spectra acquired with carbon ions suggest the presence of a small residual background from neighboring masses reaching the end of the beamline with the same energy as the rare isotope.

Preliminary measurements on the new TOF system installed at the AMS beamline of INFN-LABEC

International Nuclear Information System (INIS)

Palla, L.; Castelli, L.; Czelusniak, C.; Fedi, M.E.; Giuntini, L.; Liccioli, L.; Mandò, P.A.; Martini, M.; Mazzinghi, A.; Ruberto, C.; Schiavulli, L.; Sibilia, E.; Taccetti, F.

2015-01-01

A high resolution time of flight (TOF) system has been developed at LABEC, the 3 MV Tandem accelerator laboratory in Florence, in order to improve the sensitivity of AMS measurements on carbon samples with ultra-low concentration and also to measure other isotopes, such as "1"2"9I. The system can be employed to detect and identify residual interfering particles originated from the break-up of molecular isobars. The set-up has been specifically designed for low energy heavy ions: it consists of two identical time pick-off stations, each made up of a thin conductive foil and a Micro-Channel Plate (MCP) multiplier. The beamline is also equipped with a silicon detector, installed downstream the stop TOF station. In this paper the design of the new system and the implemented readout electronics are presented. The tests performed on the single time pick-off station are reported: they show that the maximum contribution to the timing resolution given by both the intrinsic MCP resolution and the electronics is ⩽500 ps (FWHM). For these tests, single particle pulsed beams of 2–5 MeV protons and 10 MeV "1"2C"3"+ ions, to simulate typical AMS conditions, were used. The preliminary TOF and TOF-E (TOF-energy) measurements performed with carbon beams after the installation of the new system on the AMS beam line are also discussed. These measurements were performed using the foil–MCP as the start stage and a silicon detector as the stop stage. The spectra acquired with carbon ions suggest the presence of a small residual background from neighboring masses reaching the end of the beamline with the same energy as the rare isotope.

Supernova-produced radionuclides in deep-sea sediments measured with AMS

International Nuclear Information System (INIS)

Feige, J.

2014-01-01

This thesis is dedicated to computational micromagnetics, where several new numerical methods are In this work a set of long-lived radionuclides is measured to detect supernova-traces presumably deposited on Earth 2-3 Myr ago. Approximately 100 samples of four deep-sea sediment cores (Indian Ocean) were analyzed for 26 Al, 53Mn, and 60 Fe with accelerator mass spectrometry (AMS). Additionally, 10 Be was measured to confirm the existing paleomagnetic chronology of the sediments. A signal of extraterrestrial 60 Fe, which is not produced in-situ on Earth, was detected in a time period of 1.7-3.2 Myr in the sediments used for this work. 60 Fe/ 26 Al ratios were used to calculate limits on theoretical nucleosynthesis models. A supernova-signature of 26 Al is hidden behind a terrestrial background. The measured 26 Al/ 10 Be ratios indicate, that the major source of 26 Al detected in the sediments is of atmospheric origin. Because of the extraordinarily good depth profile for the deep-sea sediments from the measured 26 Al data, this radionuclide was used for dating. (author) [de

Motility in the L3 stage is a poor phenotype for detecting and measuring resistance to avermectin/milbemycin drugs in gastrointestinal nematodes of livestock.

Science.gov (United States)

George, Melissa M; Lopez-Soberal, Lorraine; Storey, Bob E; Howell, Sue B; Kaplan, Ray M

2018-04-01

Motility is a commonly used in vitro phenotype for assessing anthelmintic activity of candidate compounds, and for detecting anthelmintic resistance in nematodes. Third-stage larvae (L3) of parasitic nematodes are commonly used in motility-based assays because L3 are simple to obtain and can remain viable in storage for extended periods. To improve the measurement of motility of microscopic stages of nematodes, our laboratory developed the Worminator, which quantitatively measures motility of parasites. Using the Worminator, we compared the dose-response characteristics of several avermectin/milbemycin (AM) compounds using L3 from both AM-susceptible and AM-resistant Cooperia spp. (abamectin, doramectin, eprinomectin, ivermectin, moxidectin) and Haemonchus contortus (eprinomectin, ivermectin, moxidectin). Concentrations tested with the Worminator ranged from 0.156 to 40 μM. Differences in EC 50 between AM-susceptible and AM-resistant isolates of Cooperia spp. and Haemonchus contortus were small, with resistance ratios ranging from 1.00 to 1.34 for Cooperia spp., 0.99 to 1.65 for Haemonchus contortus. Larval migration inhibition assays were conducted using the same isolates and were equally ineffective for detection of resistance with resistance ratios less than 2.0. These results contrast with those of the Larval Development Assay where we obtained a resistance ratio of 16.48 using the same isolates of Haemonchus contortus. Moreover, even at the highest concentration tested (40 μM), 100% inhibition of motility was never achieved and EC 50 for Worminator assays were more than 100× higher than peak plasma levels achieved in vivo following treatment. These data demonstrate that dose-response characteristics for inhibition of motility in L3 of gastrointestinal nematodes of livestock do not significantly differ for AM-susceptible and AM-resistant isolates. These data challenge the suitability of motility as a phenotype for detecting and measuring resistance to AM

Motility in the L3 stage is a poor phenotype for detecting and measuring resistance to avermectin/milbemycin drugs in gastrointestinal nematodes of livestock

Directory of Open Access Journals (Sweden)

Melissa M. George

2018-04-01

Full Text Available Motility is a commonly used in vitro phenotype for assessing anthelmintic activity of candidate compounds, and for detecting anthelmintic resistance in nematodes. Third-stage larvae (L3 of parasitic nematodes are commonly used in motility-based assays because L3 are simple to obtain and can remain viable in storage for extended periods. To improve the measurement of motility of microscopic stages of nematodes, our laboratory developed the Worminator, which quantitatively measures motility of parasites. Using the Worminator, we compared the dose-response characteristics of several avermectin/milbemycin (AM compounds using L3 from both AM-susceptible and AM-resistant Cooperia spp. (abamectin, doramectin, eprinomectin, ivermectin, moxidectin and Haemonchus contortus (eprinomectin, ivermectin, moxidectin. Concentrations tested with the Worminator ranged from 0.156 to 40 μM. Differences in EC50 between AM-susceptible and AM-resistant isolates of Cooperia spp. and Haemonchus contortus were small, with resistance ratios ranging from 1.00 to 1.34 for Cooperia spp., 0.99 to 1.65 for Haemonchus contortus. Larval migration inhibition assays were conducted using the same isolates and were equally ineffective for detection of resistance with resistance ratios less than 2.0. These results contrast with those of the Larval Development Assay where we obtained a resistance ratio of 16.48 using the same isolates of Haemonchus contortus. Moreover, even at the highest concentration tested (40 μM, 100% inhibition of motility was never achieved and EC50 for Worminator assays were more than 100× higher than peak plasma levels achieved in vivo following treatment. These data demonstrate that dose-response characteristics for inhibition of motility in L3 of gastrointestinal nematodes of livestock do not significantly differ for AM-susceptible and AM-resistant isolates. These data challenge the suitability of motility as a phenotype for detecting and measuring

Fission Cross-section Measurements of (233)U, (245)Cm and (241,243)Am at CERN n_TOF Facility

CERN Document Server

Calviani, M; Andriamonje, S; Chiaveri, E; Vlachoudis, V; Colonna, N; Meaze, M H; Marrone, S; Tagliente, G; Terlizzi, R; Belloni, F; Abbondanno, U; Fujii, K; Milazzo, P M; Moreau, C; Aerts, G; Berthoumieux, E; Dridi, W; Gunsing, F; Pancin, J; Perrot, L; Plukis, A; Alvarez, H; Duran, I; Paradela, C; Alvarez-Velarde, F; Cano-Ott, D; Gonzalez-Romero, E; Guerrero, C; Martinez, T; Villamarin, D; Vicente, M C; Andrzejewski, J; Marganiec, J; Assimakopoulos, P; Karadimos, D; Karamanis, D; Papachristodoulou, C; Patronis, N; Audouin, L; David, S; Ferrant, L; Isaev, S; Stephan, C; Tassan-Got, L; Badurek, G; Jericha, E; Leeb, H; Oberhummer, H; Pigni, M T; Baumann, P; Kerveno, M; Lukic, S; Rudolf, G; Becvar, F; Krticka, M; Calvino, F; Capote, R; Carrillo De Albornoz, A; Marques, L; Salgado, J; Tavora, L; Vaz, P; Cennini, P; Dahlfors, M; Ferrari, A; Gramegna, F; Herrera-Martinez, A; Kadi, Y; Mastinu, P; Praena, J; Sarchiapone, L; Wendler, H; Chepel, V; Ferreira-Marques, R; Goncalves, I; Lindote, A; Lopes, I; Neves, F; Cortes, G; Poch, A; Pretel, C; Couture, A; Cox, J; O'brien, S; Wiescher, M; Dillman, I; Heil, M; Kappeler, F; Mosconi, M; Plag, R; Voss, F; Walter, S; Wisshak, K; Dolfini, R; Rubbia, C; Domingo-Pardo, C; Tain, J L; Eleftheriadis, C; Savvidis, I; Frais-Koelbl, H; Griesmayer, E; Furman, W; Konovalov, V; Goverdovski, A; Ketlerov, V; Haas, B; Haight, R; Reifarth, R; Igashira, M; Koehler, P; Kossionides, E; Lampoudis, C; Lozano, M; Quesada, J; Massimi, C; Vannini, G; Mengoni, A; Oshima, M; Papadopoulos, C; Vlastou, R; Pavlik, A; Pavlopoulos, P; Plompen, A; Rullhusen, P; Rauscher, T; Rosetti, M; Ventura, A

2011-01-01

Neutron-induced fission cross-sections of minor actinides have been measured using the n_TOF white neutron source at CERN, Geneva, as part of a large experimental program aiming at collecting new data relevant for nuclear astrophysics and for the design of advanced reactor systems. The measurements at n_TOF take advantage of the innovative features of the n_TOF facility, namely the wide energy range, high instantaneous neutron flux and good energy resolution. Final results on the fission cross-section of 233U, 245Cm and 243Am from thermal to 20 MeV are here reported, together with preliminary results for 241Am. The measurement have been performed with a dedicated Fast Ionization Chamber (FIC), a fission fragment detector with a very high efficiency, relative to the very well known cross-section of 235U, measured simultaneously with the same detector.

Beryllium-10: Half-life and AMS-standards

International Nuclear Information System (INIS)

Hofmann, H.J.; Beer, J.; Bonani, G.; von Gunten, H.R.; Raman, S.; Suter, M.; Walker, R.L.; Woelfli, W.; Zimmermann, D.

1987-01-01

Absolute AMS measurements of 10 Be require reliable standards for calibration. Among the existing standards, rather large differences have been observed. These differences were found partially to be due to the different half-life values which were assumed. Also for comparison of AMS data with activity measurements, it is necessary to know the 10 Be half-life as precisely as possible. Starting with 5 ml of the standardized ORNL-MASTER solution, a working solution with a well-defined 10 Be content was prepared. Its specific activity was determined by liquid scintillation counting. This measurement yielded a new value of (1.52 +- 0.05) My for the 10 Be half-life, which is in agreement with the previously reported values but is about three times more accurate. Two independent dilution series produced new AMS standards with 10 Be/ 9 Be ratios of the order of 10 -10 and 10 -11 . These standards were measured at the ETH/SIN AMS facility with high accuracy and are compared with other available 10 Be standards. 15 refs, 2 figs., 3 tabs

Towards direction dependent fluxes with AMS-02

Energy Technology Data Exchange (ETDEWEB)

Zeissler, Stefan; Andeen, Karen; Boer, Wim de; Gebauer, Iris; Merx, Carmen; Nikonov, Nikolay; Vagelli, Valerio [Karlsruher Institut fuer Technologie KIT (Germany)

2015-07-01

The Alpha Magnetic Spectrometer (AMS-02) is a state-of-the-art particle physics detector designed to operate as an external module on the International Space Station (ISS). In the unique space environment cosmic particles can be measured with high precision over an energy range from GeV up to TeV. In 2014 electron and positron flux measurements where published which indicate an additional source of positrons among the various cosmic particles. The arrival directions of energetic positrons and electrons convey fundamental information on their origin. We evaluate the AMS-02 detector acceptance for each incoming particle direction and show preliminary results of a direction dependent measurement of the AMS-02 lepton flux.

AMS measurement of C-14 concentration in a single-year ring of a 2500-yr-old tree

International Nuclear Information System (INIS)

Sakurai, H.; Gandou, T.; Kato, W.; Sawaki, Y.; Matsumoto, T.; Aoki, T.; Matsuzaki, H.; Gunji, S.; Tokanai, F.

2004-01-01

The 14 C concentration in rings of an old tree that date back approximately 2500 yr has been measured at single-year intervals with a highly accurate liquid scintillation counter (LSC) (0.2%) to investigate the 11-yr periodicity of solar activity. To investigate the applicability of AMS to accurate 14 C measurement, 16 graphite samples produced from the cellulose of a single-year tree ring of a 2500-yr-old cedar were measured with the micro analysis laboratory tandem (MALT) accelerator, at The University of Tokyo, and the results were compared with the 14 C age determined using LSC. The average 14 C age of the single-year tree ring calculated from 16 measurements was 2496 ± 23 yr BP, corresponding to the statistical accuracy of 0.26%. This was consistent with the age of 2514 ± 23 yr BP determined using LSC within the acceptable error range, which indicates that accelerator mass spectrometry (AMS) is applicable for accurate 14 C measurement using multi-graphite for the same single-year tree ring

Measurement of the 241Am neutron capture cross section at the n_TOF facility at CERN

Directory of Open Access Journals (Sweden)

Mendoza E.

2017-01-01

Full Text Available New neutron cross section measurements of minor actinides have been performed recently in order to reduce the uncertainties in the evaluated data, which is important for the design of advanced nuclear reactors and, in particular, for determining their performance in the transmutation of nuclear waste. We have measured the 241Am(n,γ cross section at the n_TOF facility between 0.2 eV and 10 keV with a BaF2 Total Absorption Calorimeter, and the analysis of the measurement has been recently concluded. Our results are in reasonable agreement below 20 eV with the ones published by C. Lampoudis et al. in 2013, who reported a 22% larger capture cross section up to 110 eV compared to experimental and evaluated data published before. Our results also indicate that the 241Am(n,γ cross section is underestimated in the present evaluated libraries between 20 eV and 2 keV by 25%, on average, and up to 35% for certain evaluations and energy ranges.

The use of AMS to the biomedical sciences

International Nuclear Information System (INIS)

Vogel, J.S.

1991-04-01

The Center for Accelerator Mass Spectroscopy (AMS) began making AMS measurements in 1989. Biomedical experiments were originally limited by sample preparation techniques, but we expect the number of biomedical samples to increase five-fold. While many of the detailed techniques for making biomedical measurements resemble those used in other fields, biological tracer experiments differ substantially from the observational approaches of earth science investigators. The role of xenobiotius in initiating mutations in cells is of particular interest. One measure of the damage caused to the genetic material is obtained by counting the number of adducts formed by a chemical agent at a given dose. AMS allows direct measurement of the number of adducts through stoichiometric quantification of the 14 C label attached to the DNA after exposure to a labelled carcinogen. Other isotopes of interest include tritium, 36 Cl, 79 SE, 41 Ca, 26 Al and 129 I. Our experiments with low dose environmental carcinogens reflect the protocols which will become a common part of biomedical AMS. In biomedical experiments, the researcher defines the carbon to be analyzed through dissection and/or chemical purification; thus the sample is ''merely'' combusted and graphitized at the AMS facility. However, since biomedical samples can have a 14 C range of five orders of magnitude, preparation of graphite required construction of a special manifold to prevent cross-contamination. Additionally, a strain of 14 C-depleted C57BL/6 mice is being developed to further reduce background in biomedical experiments. AMS has a bright and diverse future in radioisotope tracing. Such work requires a dedicated amalgamation of AMS scientists and biomedical researchers who will redesign experimental protocols to maximize the AMS technique and minimize the danger of catastrophic contamination. 18 refs., 4 figs., 1 tab

Cultural and semantic equivalence of the activity measure post-acute care (AM-PAC) after its translation into Mandarin Chinese.

Science.gov (United States)

Chang, Feng-Hang; Ni, Pengsheng; Chiou, Hung-Yi; Hou, Wen-Hsuan; Jette, Alan M

2018-03-21

The purpose of this study was to investigate the cultural and semantic equivalence of the Activity Measure Post-Acute Care (AM-PAC) outpatient short forms after they were translated from American English to Mandarin Chinese. This study was conducted with a composite sample of a group of 483 American adults (mean age 63.1 years, 42.4% males) and 553 Taiwanese adults (mean age 60.6 years, 47.2% males) who were undergoing home care or outpatient rehabilitation services. A confirmatory factor analysis tested the cultural equivalence of the AM-PAC dimensions between the US and Taiwanese samples. Semantic equivalence was tested through an item response theory-based differential item functioning (DFI) analysis. Results of the confirmatory factor analysis demonstrated good model-data fit of the AM-PAC in both the US and Taiwanese samples. Significant DFI was found for six Basic Mobility items, two Daily Activity items, and four Applied Cognition items. A DFI-adjusted conversion table was generated to transform the raw scores of the measure for comparisons between the two countries. This study provides evidence to support the conceptual equivalence of the AM-PAC when used in rehabilitation patients between American and Taiwanese cultural contexts. Some DFI items between the two groups were found, suggesting that some differences in semantic understanding of these items between cultures require cross-cultural adjustments. Implications for Rehabilitation Cultural equivalence needs to be tested before applying a clinical measure to another context. The findings of this study supported the three activity domains that the Activity Measure Post-Acute Care measures: Basic Mobility, Daily Activity, and Applied Cognition, which are all important rehabilitation outcomes that need to be assessed and monitored across rehabilitation settings. Differential item functioning was observed between the English and Chinese versions of the Activity Measure Post-Acute Care, indicating that

Rapid method for the sequential measurement of isotopes of Am and Pu in liquid matrices by alpha spectrometry

International Nuclear Information System (INIS)

Mantero Cabrera, J.

2014-01-01

: In radiological emergencies it's necessary a fast response from the laboratories in the quantification of certain radionuclides, in order to take decisions. In these cases, is the reaction time the key parameter to consider (without neglecting the quality of the measurement). In this work, it is shown a method for aqueous matrices that generates Pu and Am isotopes sources in one single day of work, to be measured subsequently by alpha spectrometry. The developed methodology has been validated through its application to reference samples and also taking part intercom- parison exercises, having in both cases, satisfactory results. This way, we check the validity of this fast method that let us generate in 24 hours (since the sample arrives our laboratory), one measurement with a Minimun Detectable Activity (MDA) of about 0.004Bq/L for Pu and Am isotopes in liquid matrices. [es

Moessbauer and magnetic susceptibility measurements on M-type hexagonal Ba - ferrite

International Nuclear Information System (INIS)

Lipka, J.; Gruskova, A.; Sitek, J.; Miglierini, M.; Groene, R.; Hucl, M.; Toth, I.; Orlicky, O.

1990-01-01

Samples of stoichiometric BaFe 12 O 19 and Co, Ti substituted barium ferrite were prepared by chemical wet method. Moessbauer spectroscopy, magnetic susceptibility measurements, X-ray diffraction, infrared spectroscopy were conducted to examine the mechanism of formation. The observed magnetic characteristics and electron scanning microscopy show that single domain coprecipitated powders were formed. (orig.)

Aerial Measuring System (AMS)/Israel Atomic Energy Commission (IAEC) Joint Comparison Study Report

Energy Technology Data Exchange (ETDEWEB)

Wasiolek, P. [National Security Technologies, LLC. (NSTec), Mercury, NV (United States); Halevy, I. [Israel Atomic Energy Commission (IAEC), Yavne (Israel)

2013-12-23

Under the 13th Bilateral Meeting to Combat Nuclear Terrorism conducted on January 8–9, 2013, the committee approved the development of a cost-effective proposal to conduct a Comparison Study of the Aerial Measuring System (AMS) of the U.S. Department of Energy (DOE), National Nuclear Security Administration (NNSA) and Israel Atomic Energy Commission (IAEC). The study was to be held at the Remote Sensing Laboratory (RSL), Nellis Air Force Base, Las Vegas, Nevada, with measurements at the Nevada National Security Site (NNSS). The goal of the AMS and the IAEC joint survey was to compare the responses of the two agencies’ aerial radiation detection systems to varied radioactive surface contamination levels and isotopic composition experienced at the NNSS, and the differing data processing techniques utilized by the respective teams. Considering that for the comparison both teams were using custom designed and built systems, the main focus of the short campaign was to investigate the impact of the detector size and data analysis techniques used by both teams. The AMS system, SPectral Advanced Radiological Computer System, Model A (SPARCS-A), designed and built by RSL, incorporates four different size sodium iodide (NaI) crystals: 1" × 1", 2" × 4" × 4", 2" × 4" ×16", and an “up-looking” 2" × 4" × 4". The Israel AMS System, Air RAM 2000, was designed by the IAEC Nuclear Research Center – Negev (NRCN) and built commercially by ROTEM Industries (Israel) and incorporates two 2" diameter × 2" long NaI crystals. The operational comparison was conducted at RSL-Nellis in Las Vegas, Nevada, during week of June 24–27, 2013. The Israeli system, Air RAM 2000, was shipped to RSL-Nellis and mounted together with the DOE SPARCS on a DOE Bell-412 helicopter for a series of aerial comparison measurements at local test ranges, including the Desert Rock Airport and Area 3 at the NNSS. A 4-person Israeli team from the IAEC NRCN supported the activity together with 11

The implementation of depth measurement and related algorithms based on binocular vision in embedded AM5728

Science.gov (United States)

Deng, Zhiwei; Li, Xicai; Shi, Junsheng; Huang, Xiaoqiao; Li, Feiyan

2018-01-01

Depth measurement is the most basic measurement in various machine vision, such as automatic driving, unmanned aerial vehicle (UAV), robot and so on. And it has a wide range of use. With the development of image processing technology and the improvement of hardware miniaturization and processing speed, real-time depth measurement using dual cameras has become a reality. In this paper, an embedded AM5728 and the ordinary low-cost dual camera is used as the hardware platform. The related algorithms of dual camera calibration, image matching and depth calculation have been studied and implemented on the hardware platform, and hardware design and the rationality of the related algorithms of the system are tested. The experimental results show that the system can realize simultaneous acquisition of binocular images, switching of left and right video sources, display of depth image and depth range. For images with a resolution of 640 × 480, the processing speed of the system can be up to 25 fps. The experimental results show that the optimal measurement range of the system is from 0.5 to 1.5 meter, and the relative error of the distance measurement is less than 5%. Compared with the PC, ARM11 and DMCU hardware platforms, the embedded AM5728 hardware is good at meeting real-time depth measurement requirements in ensuring the image resolution.

Produção de prolina e suscetibilidade ao glufosinato de amônio em plantas transgênicas de citrumelo Swingle Proline production by transgenic plants of Swingle citrumelo and susceptibility to glufosinate ammonium

Directory of Open Access Journals (Sweden)

Cristine Elizabeth Alvarenga Carneiro

2006-05-01

Full Text Available O objetivo deste trabalho foi avaliar a sensibilidade de plantas transgênicas de citrumelo Swingle com elevada produção de prolina, ao herbicida glufosinato de amônio. As plantas utilizadas apresentavam a inserção do gene mutante da enzima delta1-pirrolina-5-carboxilato sintetase (P5CS, responsável pela biossíntese de prolina. A expressão do gene p5cs em plantas transgênicas causou aumento nas quantidades de prolina em tecidos foliares, em até cinco vezes, quando comparadas às plantas-controle tratadas com 200 µM de glufosinato de amônio. As plantas transgênicas acumularam maior quantidade de NH4+ nas folhas, em relação às plantas não-transgênicas. Os danos causados pelo herbicida foram avaliados in vitro, utilizando-se discos foliares cultivados em meio MS com diferentes concentrações de glufosinato de amônio. Observou-se maior clorose em discos foliares das plantas transgênicas, o que comprova a maior suscetibilidade de plantas de citrumelo Swingle com alta produção de prolina ao herbicida.The objective of this work was to evaluate the susceptibility to glufosinate ammonium of transgenic plants of Swingle citrumelo with high proline production. The mutant gene of the enzyme delta1-pyrroline-5-carboxylate synthetase (P5CS, the rate-limiting enzyme in proline biosynthesis, was inserted into Swingle citrumelo plants. The expression of the gene p5cs caused up to 5-fold increase on the proline content in leaf tissues of transgenic plants treated with 200 µM glufosinate ammonium, when compared with control plants. Leaves of transgenic plants accumulated higher amounts of NH4+ than the nontransgenic control. The herbicide toxicity was evaluated using leaf disks cultivated in MS medium, containing different concentrations of glufosinate ammonium. The severity of the chlorosis, observed in leaf disks of transgenic plants, confirmed the higher susceptibility of Swingle citrumelo plants, with high proline production, to this

IDENTIFYING ANTHROPOGENIC METALLIC POLLUTANTS USING FREQUENCY DEPENDENT MAGNETIC SUSCEPTIBILITY MEASUREMENTS IN ABUJA METROPOLIS

Directory of Open Access Journals (Sweden)

Jatto S. Solomon

2017-07-01

Full Text Available Soil formed from lithological and weathering processes of parent rocks generally exhibit paramagnetic properties due to some minerals contained in the rocks and thus have significant value of magnetic susceptibility. This susceptibility arising from the influence of the parent rocks tend to mask anthropogenic grains pollutants released into the environment by human activities. Hence, it becomes difficult to identify the effect of the lithological and anthropogenic magnetic susceptibility in complex soil found in urban areas. The superparamagnetic effect of lithological soil, a single state domain and multi-domain state of anthropogenic grains can easily be investigated by frequency dependent measurements where readings between 0-2.0% indicates the absence of lithological influence, 2.0-8.0% indicates multi-domain grains or mixture of both single stage and multi-domian grains and 8.0-12% indicates the superparamagntic (SP grain from lithological origin. In this work frequency dependent measurements were carried out along 5 selected road networks within the 5 districts of Abuja phase 1. Measurements were also carried out in 379 random points at the surface and depth of 40.0cm to investigate the distribution of anthropogenic grains in Abuja metropolis using the Bartington susceptibility meter. Frequency dependent measurements along the selected road networks indicate0-3.0% immediately after the roads pavement to a distance of about 3.0m from the road, indicating that the magnetic susceptibility arise mostly form anthropogenic influence rather than lithological processes. At the distance of 3.0-8.0m, frequency dependent values of about 3.0-8.0% were recorded, indicating mixture of both superparamagnetic and multi-domain grains. Beyond the distance of 8.0m, the frequency dependent values are mostly above 8.0.0%, indicating virtually all SP grains. The spatial distribution frequency dependent surface map shows the presence of anthropogenic grains in

Electronic structure of Pu-Ce(-Ga) and Pu-Am(-Ga) alloys, stabilized in the {delta} phase; Structure electronique d'alliages Pu-Ce(-Ga) et Pu-Am(-Ga) stabilises en phase {delta}

Energy Technology Data Exchange (ETDEWEB)

Dormeval, M

2001-09-01

The behaviour of {delta}-plutonium, stable between 319 and 451 deg C, exhibits numerous singularities which are still a mystery for both physicists and metallurgists. This is due to its complex electronic structure, and in particular to the 5f electrons, which are at the edge between localization and delocalization. The stability domain of the {delta} phase can be extended down to room temperature by alloying with so called 'deltagen atoms' such as gallium (Ga), aluminum (A1), cerium (Ce) or americium (Am). The present work deals, one the one hand, with the influence of cerium and americium solutes regarding the localization of the 5f electrons of {delta}-plutonium, in binary Pu-Ce and Pu-Am alloys. On the other hand, the effect of two different deltagen solutes, simultaneously present, on the stability of the {delta} phase has been studied in ternary Pu-Am-Ga and Pu-Ce-Ga alloys. The electronic structure being strongly related to the crystalline organization, characterization methods such as X-Ray diffraction and EXAFS measurements were used together with electrical resistivity and magnetic susceptibility experiments. These showed that the roles of cerium and americium, supposed to be similar at the beginning of this investigation, are actually very different. Moreover, the additive effect of cerium and gallium, and, americium and gallium, has been demonstrated. Studying plutonium alloys, which are radioactive, also means following their evolution in time. The characteristics of the alloys have then been followed which allowed to detect, in Pu-Ce(-Ga) alloys, a destabilization of the {delta} phase and, to observe, in Pu-Am(-Ga) alloys, the influence of self-irradiation defects on the magnetic response. (author)

Status of AMS at the China Institute of Atomic Energy

International Nuclear Information System (INIS)

Jiang Shan; He Ming; Hu Yueming; Yuan Jian

2007-01-01

The first accelerator mass spectrometry (AMS) system in China was set up at the China Institute of Atomic Energy in 1989. In the following years, long-lived nuclides 10 Be, 26 Al, 36 Cl, 41 Ca, 79 Se and 129 I were measured in geology, environment and biology samples. The newly development of the AMS measurement and applications in recent years were introduced. The current projects include upgrading of AMS injection system for increasing mass resolution, new particle identification techniques for separation of isobars, development of the AMS measurement methods for 99 Tc, 93 Zr, 151 Sm and 182 Hf analyses, and applications in biology, environment and nuclear astrophysics. (authors)

AMS02 Ecal γ trigger performance measured at the October 2004 CERN test beam

International Nuclear Information System (INIS)

Brun, Pierre; Rosier-Lees, Sylvie

2006-01-01

Test beam data collected in October 2004 at CERN PS to validate the AMS 02 Ecal Inter- mediate Board (EIB) are analyzed. After describing the experimental setup and the event samples, results concerning noise measurement, trigger efficiency and threshold accuracy are presented. They demonstrate that the EIB fulfills the physics requirements. Therefore the analog part of the trigger is validated, and hardware choices are also made towards the final device. (authors)

AmO₂ Analysis for Analytical Method Testing and Assessment: Analysis Support for AmO₂ Production

Energy Technology Data Exchange (ETDEWEB)

Kuhn, Kevin John [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Bland, Galey Jean [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Fulwyler, James Brent [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Garduno, Katherine [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Keller, Russell C. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Klundt, Dylan James [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Lujan, Elmer J. W [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mark, Zoe Francoise Elise [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Mathew, Kattathu Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ortega, Laura Claire [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Ottenfeld, Chelsea Faith [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Porterfield, Donivan R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rearick, Michael Sean [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Rim, Jung Ho [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Schake, Ann Rene [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Schappert, Michael Francis [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Stanley, Floyd E. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Thomas, Mariam R. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Wylie, Ernest Miller II [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Xu, Ning [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tandon, Lav [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

2017-09-08

Americium oxide samples will be measured for various analytes to support AmO₂ production. The key analytes that are currently requested by the Am production customer at LANL include total Am content, Am isotopics, Pu assay, Pu isotopics, and trace element content including ²³⁷Np content. Multiple analytical methods will be utilized depending on the sensitivity, accuracy and precision needs of the Am matrix. Traceability to the National Institute of Standards and Technology (NIST) will be achieved, where applicable, by running NIST traceable quality control materials. This given that there are no suitable AmO₂ reference materials currently available for requested analytes. The primary objective is to demonstrate the suitability of actinide analytical chemistry methods to support AmO₂ production operations.

Background and record of AMS measurements in JMSF

International Nuclear Information System (INIS)

Shima, Shigeki; Gasa, Sin'ichi

2010-01-01

Japan Marine Science Foundation (JMSF) has become a member of the users in the JAEA-Mutsu-AMS from 1999 and has determined concentrations of 14 C and 129 I in a wide variety of samples. They were relevant to radioecology, geology, and archaeology as well as oceanography. In this report, our activities over the past 10 years are described. (author)

Electronic structure of Pu-Ce(-Ga) and Pu-Am(-Ga) alloys, stabilized in the {delta} phase; Structure electronique d'alliages Pu-Ce(-Ga) et Pu-Am(-Ga) stabilises en phase {delta}

Energy Technology Data Exchange (ETDEWEB)

Dormeval, M

2001-09-01

The behaviour of {delta}-plutonium, stable between 319 and 451 deg C, exhibits numerous singularities which are still a mystery for both physicists and metallurgists. This is due to its complex electronic structure, and in particular to the 5f electrons, which are at the edge between localization and delocalization. The stability domain of the {delta} phase can be extended down to room temperature by alloying with so called 'deltagen atoms' such as gallium (Ga), aluminum (A1), cerium (Ce) or americium (Am). The present work deals, one the one hand, with the influence of cerium and americium solutes regarding the localization of the 5f electrons of {delta}-plutonium, in binary Pu-Ce and Pu-Am alloys. On the other hand, the effect of two different deltagen solutes, simultaneously present, on the stability of the {delta} phase has been studied in ternary Pu-Am-Ga and Pu-Ce-Ga alloys. The electronic structure being strongly related to the crystalline organization, characterization methods such as X-Ray diffraction and EXAFS measurements were used together with electrical resistivity and magnetic susceptibility experiments. These showed that the roles of cerium and americium, supposed to be similar at the beginning of this investigation, are actually very different. Moreover, the additive effect of cerium and gallium, and, americium and gallium, has been demonstrated. Studying plutonium alloys, which are radioactive, also means following their evolution in time. The characteristics of the alloys have then been followed which allowed to detect, in Pu-Ce(-Ga) alloys, a destabilization of the {delta} phase and, to observe, in Pu-Am(-Ga) alloys, the influence of self-irradiation defects on the magnetic response. (author)

Crystallography and magnetic properties of transuranium element oxygen compounds (Np, Pu and Am)

International Nuclear Information System (INIS)

Tabuteau, Alain.

1981-05-01

This paper includes: 1) The brief description of the experimental techniques used for analyzing very small quantities of solid radioactive compounds (differential thermal micro-analyses, diffraction of X rays, magnetic susceptibility and Moessbauer resonance). 2) The methods of synthesis of the ternary oxides of transuranic elements at oxidation degrees III (Pu 2 MoO 6 , Pu 2 WO 6 , Pu 2 (WO 4 ) 3 , Am 2 MoO 6 , Am 2 WO 6 , Am 2 (MoO 4 ) 3 and Am 2 (WO 4 ) 3 ) and at degree IV (Np(VO 3 ) 4 , Np(MoO 4 ) 2 , Np(WO 4 ) 2 and Pu(MoO 4 ) 2 ). The drawing up of liquid-solid balance diagrams enabled the field of stability of molybdate (or tungstate) systems of alkaline transuranic - mobybdates (or tungstates) to be clarified. 3) The study of the structural properties of the identified phases. These results taken as a whole made it possible to establish a ''comparative crystal - chemistry'' of the oxigenated phases of Np, Pu and Am with those of the thorium and uranium actinide elements and with the rare earths of adjacent ionic radius. 4) The Moessbauer resonance study of 237 Np in the solid solution Usub(1-x)Npsub(x)O 2 (0 [fr

Aerial Measuring System (AMS)/Israel Atomic Energy Commission (IAEC) Joint Comparison Study Report

International Nuclear Information System (INIS)

Wasiolek, P.; Halevy, I.

2013-01-01

Under the 13th Bilateral Meeting to Combat Nuclear Terrorism conducted on January 8-9, 2013, the committee approved the development of a cost-effective proposal to conduct a Comparison Study of the Aerial Measuring System (AMS) of the U.S. Department of Energy (DOE), National Nuclear Security Administration (NNSA) and Israel Atomic Energy Commission (IAEC). The study was to be held at the Remote Sensing Laboratory (RSL), Nellis Air Force Base, Las Vegas, Nevada, with measurements at the Nevada National Security Site (NNSS). The goal of the AMS and the IAEC joint survey was to compare the responses of the two agencies' aerial radiation detection systems to varied radioactive surface contamination levels and isotopic composition experienced at the NNSS, and the differing data processing techniques utilized by the respective teams. Considering that for the comparison both teams were using custom designed and built systems, the main focus of the short campaign was to investigate the impact of the detector size and data analysis techniques used by both teams. The AMS system, SPectral Advanced Radiological Computer System, Model A (SPARCS-A), designed and built by RSL, incorporates four different size sodium iodide (NaI) crystals: 1'' x 1'', 2'' x 4'' x 4'', 2'' x 4'' x16'', and an ''up-looking'' 2'' x 4'' x 4''. The Israel AMS System, Air RAM 2000, was designed by the IAEC Nuclear Research Center - Negev (NRCN) and built commercially by ROTEM Industries (Israel) and incorporates two 2'' diameter x 2'' long NaI crystals. The operational comparison was conducted at RSL-Nellis in Las Vegas, Nevada, during week of June 24-27, 2013. The Israeli system, Air RAM 2000, was shipped to RSL-Nellis and mounted together with the DOE SPARCS on a DOE Bell-412 helicopter for a series of aerial comparison measurements at local test

A Systematic Comparison of the Anisotropy of Magnetic Susceptibility (AMS) and Anisotropy of Remanence (ARM) Fabrics of Ignimbrites: Examples from the Quaternary Bandelier Tuff, Jemez Mountains, New Mexico and Miocene Ignimbrites Near Gold Point, Nevada

Science.gov (United States)

Lycka, Ranyah

Anisotropy of magnetic susceptibility (AMS) has been widely used to define petrofabrics in silicic, elevated-temperature pyroclastic deposits (i.e., ignimbrites) and these fabrics have been successfully utilized to infer pyroclastic emplacement, or transport, directions in many cases. Selected exposures of the Quaternary Bandelier Tuff, exposed in the Jemez Mountains, New Mexico, have been studied to systematically compare anisotropy of remanence (mainly anhysteretic remanent magnetization, AARM) with AMS data from the same sites. In addition, as part of a broad study to understand the Neogene history of deformation associated with a displacement transfer system in the western Great Basin, paleomagnetic and magnetic fabric data have been collected from ignimbrites that originated from the Timber Mountain Caldera complex, active from about 14 to 11.5 Ma. Here, AMS and AARM are compared for 21 (9-12 samples per site) sites in the Quaternary Bandelier Tuff, and 15 (9-10 samples per site) sites in Timber Mountain ignimbrites, with each chosen to examine the effects of varying degrees of welding and crystal content on the fabrics obtained. The relationships between AARM and AMS fabrics for the selected sites are not uniform, and include normal, intermediate, reverse, and oblique fabrics. The differences may be controlled by the degree of welding and/or crystal content, which requires further explanation. Ultimately, the fabrics identified in both suites of rocks are compared with anisotropy of isothermal remanent magnetization (AIRM) data, along with other rock magnetic data, to more fully evaluate the domain state control on the fabrics.

The ETH Zurich AMS facilities: Performance parameters and reference materials

Energy Technology Data Exchange (ETDEWEB)

Christl, M., E-mail: mchristl@phys.ethz.ch [Laboratory of Ion Beam Physics, ETH Zurich, 8093 Zurich (Switzerland); Vockenhuber, C.; Kubik, P.W.; Wacker, L.; Lachner, J.; Alfimov, V.; Synal, H.-A. [Laboratory of Ion Beam Physics, ETH Zurich, 8093 Zurich (Switzerland)

2013-01-15

The current performance of all three AMS systems in operation at ETH Zurich, the 6 MV HVEC EN-Tandem facility 'TANDEM', the 0.5 MV NEC Pelletron 'TANDY', and the 0.2 MV system 'MICADAS' is summarized. Radionuclides routinely measured with these AMS systems include {sup 10}Be, {sup 14}C, {sup 26}Al, {sup 36}Cl, {sup 41}Ca, {sup 129}I and the actinides. The reference materials used for the normalization of the AMS measurements at the ETH Zurich AMS facilities are presented. This paper therefore is a comprehensive status report of all three AMS systems currently operated by the Laboratory of Ion Beam Physics (LIP) at ETH Zurich and documents their performance and operation parameters.

Fission cross section measurement of Am-242m using lead slowing-down spectrometer

Energy Technology Data Exchange (ETDEWEB)

Kai, Tetsuya; Kobayashi, Katsuhei; Yamamoto, Shuji; Fujita, Yoshiaki [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst.; Kimura, Itsuro; Ohkawachi, Yasushi; Wakabayashi, Toshio

1998-03-01

By making use of double fission chamber and lead slowing-down spectrometer coupled to an electron linear accelerator, fission cross section for the {sup 242m}Am(n,f) reaction has been measured relative to that for the {sup 235}U(n,f) reaction in the energy range from 0.1 eV to 10 keV. The measured result was compared with the evaluated nuclear data appeared in ENDF/B-VI and JENDL-3.2, of which evaluated data were broadened by the energy resolution function of the spectrometer. Although the JENDL-3.2 data seem to be a little smaller than the present measurement, good agreement can be seen in the general shape and the absolute values. The ENDF/B-VI data are larger more than 50 % than the present values above 3 eV. (author)

Operational status of the JAEA-Mutsu tandetron AMS

International Nuclear Information System (INIS)

Kabuto, Shoji; Kinoshita, Naoki; Amano, Hikaru; Watanabe, Yukiya; Baba, Masami

2008-01-01

A Tandetron AMS (Accelerator Mass Spectrometer) had been set up at the Japan Atomic Energy Agency (formerly the Japan Atomic Energy Research Institute), Mutsu in 1997. The AMS features 3MV Tandetron accelerator and two independent beamlines for 14 C and 129 I measurement. In this paper, we describe the current status and troubles for the Tandetron AMS with the showing of examples from the last year. (author)

Critical current density measurement of thin films by AC susceptibility based on the penetration parameter h

DEFF Research Database (Denmark)

Li, Xiao-Fen; Grivel, Jean-Claude; Abrahamsen, Asger B.

2012-01-01

We have numerically proved that the dependence of AC susceptibility χ of a E(J) power law superconducting thin disc on many parameters can be reduced to one penetration parameter h, with E the electric field and J the current density. Based on this result, we propose a way of measuring the critical...... current density Jc of superconducting thin films by AC susceptibility. Compared with the normally used method based on the peak of the imaginary part, our method uses a much larger range of the AC susceptibility curve, thus allowing determination of the temperature (T) dependence of Jc from a normally...

Modified thermogravimetric apparatus to measure magnetic susceptibility on-line during annealing of metastable ferromagnetic materials

International Nuclear Information System (INIS)

Luciani, G.; Constantini, A.; Branda, F.; Ausanio, G.; Hison, C.; Iannotti, V.; Luponio, C.; Lanotte, L.

2004-01-01

The insertion of proper coils to generate a magnetic field, with controlled gradient, in a standard thermogravimetric apparatus is shown to be a valid solution to measure on-line, upon heat treatment, the magnetic susceptibility in ribbon shaped samples of a metastable ferromagnetic material. The method is very useful to individuate the annealing conditions that optimise soft or hard magnetic properties without using separate apparatuses for heat treatment, control of the structural phase transition and characterization of magnetic susceptibility

Installation and measurement capacity of 3 x 592 GBq 241Am-Be neutron irradiation cell

International Nuclear Information System (INIS)

Bulut, Serdar; Celenk, I.

2013-01-01

In this study, the installation and measurement capacity of the neutron irradiation system are investigated. First of all an irradiation geometry enabling optimum irradiation was designed for three 241 Am-Be sources each of it having 592 GBq activity. Neutron irradiation system was installed after design and optimization of the system including the design of appropriate moderator and shielding were completed. Radiation safety standards of the Neutron Research Laboratory fulfilling the requirements of national regulation were achieved with unique configuration of the shielding materials. In this study the results of qualitative and quantitative detection limits obtained for Na, Al, Cl, K, Ti, V, Mn, Fe, Co, Cu, Zn, Ga, Ge, As, Se, Br, Rb, Sr, Y, Mo, Ru, Ag, Cd, In, Sb, I, Cs, Ba, La, Ce, Pr, Nd, Sm, Eu, Gd, Dy, Ho, Yb, Lu, Hf, W, Pt, Au, Th and U elements by using the neutron irradiation cell comprising 3 x 592 GBq 241 Am-Be isotopic neutron source are presented and discussed. (orig.)

A decade of AMS at University of Georgia

International Nuclear Information System (INIS)

Culp, Randy; Noakes, John; Cherkinsky, Alex; Ravi Prasad, G.V.; Dvoracek, Doug

2013-01-01

In a span of 10 years, University of Georgia’s Center for Applied Isotope Studies (CAIS) has transformed itself from principally a liquid scintillation counting (LSC) laboratory to one conducting thousands of accelerator mass spectrometry (AMS) and stable isotope ratio analysis (SIRA) annually. After receiving the first of the NEC compact AMS units in the United States, the CAIS began to meet the demand for 14 C analysis outside the normal realm of most radiocarbon dating laboratories. With industry’s support, isotope research continued on an already developing natural products program to authenticate materials origin and process of formation. The CAIS’s AMS allowed for the detection of synthetic materials in milligram quantities rather than gram quantities required by LSC and allowed new compound specific SIRA techniques to be directed toward compound specific 14 C measurement. By 2005 the CAIS was one of only a few laboratories accredited to determine bio-base content in industrial fuels and products by both AMS and LSC following ASTM D6866-10 [1]. Since 2001, when our first sample was analyzed by AMS method, both radiocarbon and natural products sample numbers have increased steadily. The advantages of AMS analysis in overall efficiency, cost savings, accuracy, and precision, are detailed here in a review of analytical precision for radiocarbon and natural products analyzed over 10 years of AMS operation. Comparisons are made between natural products and bio-based materials analyzed by both AMS and LSC. Although high precision is not required to authenticate natural products, for the purpose of product comparison with regard to degree of naturalness accurate and precise 14 C measurement is shown to be achievable by both methods.

Operational status of the JAEA-MUTSU tandetron AMS 2008-2009

International Nuclear Information System (INIS)

Kabuto, Shoji; Kinoshita, Naoki; Tanaka, Takayuki; Yamamoto, Nobuo

2010-01-01

A Tandetron Accelerator Mass Spectrometer (AMS) manufactured by High Voltage Engineering Europa in Netherlands had been set up at the Mutsu office of Aomori Research and Development Center, Japan Atomic Energy Agency (JAEA) in 1997. This AMS features 3MV Tandetron accelerator and two independence beamlines for 14 C and 129 I measurement. This AMS has measured both internal and external JAEA researcher's samples based on an open door policy since April 2006. Furthermore, the total operation time of this AMS from the routine operation started exceeds more than 20,000 hours in this year. In this report, we describe not only the summary of the current status and troubles from the previous symposium but also the upgrading of the operation system in this AMS which is carried out from June to July in 2009. (author)

Technical advances at the ANTARES AMS centre

International Nuclear Information System (INIS)

Lawson, E.M.; Fink, D.; Hotchkis, M.A.C.; Hua, Q.; Jacobsen, G.; Smith, A.M.

1998-01-01

Full text: Accelerator Mass Spectrometry (AMS) began at ANTARES in late 1991. Many technical improvements and upgrades to the AMS measurement system have taken place since then. The AMS Centre routinely measures 14C (to better than 1% precision), 36Cl and 129I. The capability to measure 10Be and 26Al, is established although further development is still in progress. A capability to analyse Actinides is being established and is the subject of another paper to this conference. This paper reviews some of the more recent technical improvements to the facility. For our 14C analyses a new gas stripper system and high resolution ExB velocity analyser have been installed and are in routine operation. The gas stripper is also used for most other isotopes. A new 90 degree spherical ESA allows 129I measurements without the need for time-of-flight analysis. Installation of a critical insulation flange in the isotope cycling system has permitted bouncing of 12C- and the measurement of 13C/12C ratios. A complete set of Dowlish tubes now allows spark free operation to 8 MV for our 10Be and 36Cl measurements. The very recent installation of pelletron chains is being assessed

Quality control for measurement of soil samples containing 237Np and 241Am as radiotracer

International Nuclear Information System (INIS)

Sha Lianmao; Zhang Caihong; Song Hailong; Ren Xiaona; Han Yuhu; Zhang Aiming; Chu Taiwei

2003-01-01

This paper reports quality control (QC) for the measurement of soil samples containing 237 Np and 241 Am as radiotracers in migration test of transuranic nuclides. All of the QC were done independently by the QA members of analytical work. It mainly included checking 5%-10% of the total analyzed samples; preparing blank samples, blind replicate sample and spiked samples used as quality control samples to check the quality of analytical work

International key comparison of measurements of neutron source emission rate (1999-2005): CCRI(III)-K9.AmBe

Energy Technology Data Exchange (ETDEWEB)

Roberts, N.J.; Jones, L.N. [National Physical Laboratory (NPL), Teddington, (United Kingdom); Wang, Z.; Liu, Y.; Wang, Q.; Chen, X.; Luo, H.; Rong, C. [China Institute of Atomic Energy (CIAE), Beijing (China); Kralik, M. [Czech Metrology Institute (CMI), Praha, (Czech Republic); Park, H.; Choi, K.O. [Korea Research Institute of Standards and Science (KRISS), Daejeon, (Korea, Republic of); Pereira, W.W.; Da Fonseca, E.S. [National Laboratory of Metrology of Ionizing Radiation (LNMRI), Rio de Janeiro, (Brazil); Cassette, P. [Laboratoire National Henri Becquerel (LNE-LNHB), Paris, (France); Dewey, M.S. [National Institute of Standards and Technology (NIST), Gaithersburg, MD, (United States); Moiseev, N.N.; Kharitonov, I.A. [D I Mendeleyev Institute for Metrology (VNIIM), St Petersburg, (Russian Federation)

2011-07-01

Section III (neutron measurements) of the Comite Consultatif des Rayonnements Ionisants, CCRI, conducted a key comparison of primary measurements of the neutron emission rate of an {sup 241}Am-Be({alpha},n) radionuclide source. A single {sup 241}Am-Be({alpha},n) source was circulated to all the participants between 1999 and 2005. Eight laboratories participated - the CIAE (China), CMI (Czech Republic), KRISS (Republic of Korea), LNMRI (Brazil), LNE-LNHB (France), NIST (USA), NPL (UK) and the VNIIM (Russian Federation) - with the NPL making their measurements at the start and repeating them near the end of the exercise to verify the stability of the source. Each laboratory reported the emission rate into 4{pi} sr together with a detailed uncertainty budget. All participants used the manganese bath technique, with the VNIIM also making measurements using an associated particle technique. The CMI, KRISS, VNIIM, and later the NPL, also measured the anisotropy of the source although this was not a formal part of the comparison. The first draft report was released in May 2006 and having been discussed and modified by the participants and subsequently reviewed by the CCRI(III), the present paper is now the final report of the comparison. (authors)

Susceptibility-Weighted Imaging and Quantitative Susceptibility Mapping in the Brain

Science.gov (United States)

Liu, Chunlei; Li, Wei; Tong, Karen A.; Yeom, Kristen W.; Kuzminski, Samuel

2015-01-01

Susceptibility-weighted imaging (SWI) is a magnetic resonance imaging (MRI) technique that enhances image contrast by using the susceptibility differences between tissues. It is created by combining both magnitude and phase in the gradient echo data. SWI is sensitive to both paramagnetic and diamagnetic substances which generate different phase shift in MRI data. SWI images can be displayed as a minimum intensity projection that provides high resolution delineation of the cerebral venous architecture, a feature that is not available in other MRI techniques. As such, SWI has been widely applied to diagnose various venous abnormalities. SWI is especially sensitive to deoxygenated blood and intracranial mineral deposition and, for that reason, has been applied to image various pathologies including intracranial hemorrhage, traumatic brain injury, stroke, neoplasm, and multiple sclerosis. SWI, however, does not provide quantitative measures of magnetic susceptibility. This limitation is currently being addressed with the development of quantitative susceptibility mapping (QSM) and susceptibility tensor imaging (STI). While QSM treats susceptibility as isotropic, STI treats susceptibility as generally anisotropic characterized by a tensor quantity. This article reviews the basic principles of SWI, its clinical and research applications, the mechanisms governing brain susceptibility properties, and its practical implementation, with a focus on brain imaging. PMID:25270052

Susceptibility-weighted imaging and quantitative susceptibility mapping in the brain.

Science.gov (United States)

Liu, Chunlei; Li, Wei; Tong, Karen A; Yeom, Kristen W; Kuzminski, Samuel

2015-07-01

Susceptibility-weighted imaging (SWI) is a magnetic resonance imaging (MRI) technique that enhances image contrast by using the susceptibility differences between tissues. It is created by combining both magnitude and phase in the gradient echo data. SWI is sensitive to both paramagnetic and diamagnetic substances which generate different phase shift in MRI data. SWI images can be displayed as a minimum intensity projection that provides high resolution delineation of the cerebral venous architecture, a feature that is not available in other MRI techniques. As such, SWI has been widely applied to diagnose various venous abnormalities. SWI is especially sensitive to deoxygenated blood and intracranial mineral deposition and, for that reason, has been applied to image various pathologies including intracranial hemorrhage, traumatic brain injury, stroke, neoplasm, and multiple sclerosis. SWI, however, does not provide quantitative measures of magnetic susceptibility. This limitation is currently being addressed with the development of quantitative susceptibility mapping (QSM) and susceptibility tensor imaging (STI). While QSM treats susceptibility as isotropic, STI treats susceptibility as generally anisotropic characterized by a tensor quantity. This article reviews the basic principles of SWI, its clinical and research applications, the mechanisms governing brain susceptibility properties, and its practical implementation, with a focus on brain imaging. © 2014 Wiley Periodicals, Inc.

Chlorine measurements at the 5MV French AMS national facility ASTER: Associated external uncertainties and comparability with the 6MV DREAMS facility

Science.gov (United States)

Braucher, R.; Keddadouche, K.; Aumaître, G.; Bourlès, D. L.; Arnold, M.; Pivot, S.; Baroni, M.; Scharf, A.; Rugel, G.; Bard, E.

2018-04-01

After 6 years of 36Cl routine operation, more than 6000 unknown samples have been measured at the 5MV French accelerator mass spectrometry (AMS) national facility ASTER (CEREGE, Aix en Provence). This paper presents the long term behavior of ASTER through the analysis of the measurements of the most used chlorine standards and reference materials, KNSTD1600, SM-Cl-12 and SM-CL-13 over a 46 months' time period. Comparison of measured chlorine concentrations (both 35Cl and 36Cl) from ice samples on two AMS facilities operating at 5MV (ASTER) and 6MV (DREAMS, Helmholtz-Zentrum Dresden-Rossendorf) and normalizing to two different reference materials agree within uncertainties making both reference materials (SM-Cl-12 and KNSTD1600) suitable for 36Cl measurement at ASTER.

Measurement of the cosmic positrons' spectrum with the experiment AMS-02 and search for exotic signals; Mesure du spectre de positons cosmiques avec l'experience AMS-02 et recherche de signaux exotiques

Energy Technology Data Exchange (ETDEWEB)

Pochon, J

2005-06-15

The AMS-02 experiment is a particle detector that will be installed on the international space station (ISS) in 2008 for at least 3 years. The physics motivations are cosmic ray measurements (e-, e+, p, p-bar, {gamma}, He, C,...), antimatter search for Z>2 and gamma ray studies from GeV to TeV. The HEAT experiment has measured positron spectrum up to 30 GeV, and shown a possible distortion around 8 GeV, which can be interpreted as a dark matter signal. The cosmic positrons spectrum measurement needs positron/proton separation close to 10{sup 5}, which will be obtained combining all AMS-02 sub-detectors. A neural network analysis has been developed on test beam data taken in 2002, to estimate the electron/proton rejection for the electromagnetic calorimeter. This technique, based on discriminant variables and which was tuned on data, was used to determine the positron acceptance combining other sub-detectors information. The number of conventional positrons can be estimated and AMS ability to detect cold dark matter signals has been determined. This study was presented for signal from supersymmetric neutralinos and from Kaluza-Klein stable particles. Fluxes are naturally too low to be detected. Signal can be enhanced thanks to local dark matter over-densities which appear naturally in galaxy formation models. A model for those over-densities has been tuned and presented. (author)

Multiscale structural characterizations of mixed U(iv)-An(iii) oxalates (An(iii) = Pu or Am) combining XAS and XRD measurements.

Science.gov (United States)

Arab-Chapelet, B; Martin, P M; Costenoble, S; Delahaye, T; Scheinost, A C; Grandjean, S; Abraham, F

2016-04-28

Mixed actinide(III,IV) oxalates of the general formula M2.2UAn(C2O4)5·nH2O (An = Pu or Am and M = H3O(+) and N2H5(+)) have been quantitatively precipitated by oxalic precipitation in nitric acid medium (yield >99%). Thorough multiscale structural characterization using XRD and XAS measurements confirmed the existence of mixed actinide oxalate solid solutions. The XANES analysis confirmed that the oxidation states of the metallic cations, tetravalent for uranium and trivalent for plutonium and americium, are maintained during the precipitation step. EXAFS measurements show that the local environments around U(+IV), Pu(+III) and Am(+III) are comparable, and the actinides are surrounded by ten oxygen atoms from five bidentate oxalate anions. The mean metal-oxygen distances obtained by XAS measurements are in agreement with those calculated from XRD lattice parameters.

Cosmic rays measurements between 1 GeV and 1 PeV by AMS and CREAM experiments

International Nuclear Information System (INIS)

Mangin-Brinet, M.

2007-11-01

The AMS (Alpha Magnetic Spectrometer) and CREAM (Cosmic Ray Energetics and Mass) experiments that are devoted to the detection of cosmic radiations have a similar architecture and both use a Cherenkov detector whose scintillating material is a silicon aerogel. The performance of the Cherenkov detector rests on an accurate knowledge of the refractive index of the aerogel plane. This report deals with an adequate methodology of measuring the refractive index. The first chapter reviews the contributions of AMS and CREAM experiments to the physics of cosmic radiations. The second chapter presents different methods used for mapping the refractive index of the aerogel plane. The prism method is based on the measurement of the deflection of a laser beam through the sides of an aerogel tile. The most satisfying method to measure the changes in the refractive index is to use an electron beam, in this case any change infers a change in the emission angle of the Cherenkov photons that can be detected and the value of the refractive index is deduced. A new method based on the deflection of a laser beam on the 2 parallel sides of an aerogel tile has been developed. The characterization of the 2 Cherenkov detectors are given in the second and the third chapter. The last chapter presents some aspects of the simulation works and of the data processing. (A.C.)

Development of the MICROMEGAS Detector for Measuring the Energy Spectrum of Alpha Particles by using a 241-Am Source

CERN Document Server

Kim, Do Yoon; Shin, Jae Won; Park, Tae-Sun; Hong, Seung-Woo; Andriamonje, Samuel; Kadi, Yacine; Tenreiro, Claudio

2016-01-01

We have developed MICROMEGAS (MICRO MEsh GASeous) detectors for detecting {\\alpha} particles emitted from an 241-Am standard source. The voltage applied to the ionization region of the detector is optimized for stable operation at room temperature and atmospheric pressure. The energy of {\\alpha} particles from the 241-Am source can be varied by changing the flight path of the {\\alpha} particle from the 241 Am source. The channel numbers of the experimentally-measured pulse peak positions for different energies of the {\\alpha} particles are associated with the energies deposited by the alpha particles in the ionization region of the detector as calculated by using GEANT4 simulations; thus, the energy calibration of the MICROMEGAS detector for {\\alpha} particles is done. For the energy calibration, the thickness of the ionization region is adjusted so that {\\alpha} particles may completely stop in the ionization region and their kinetic energies are fully deposited in the region. The efficiency of our MICROMEGA...

Earth and environmental sciences by accelerator mass spectrometry (AMS) with the large tandem accelerator

International Nuclear Information System (INIS)

Sasa, K.; Takahashi, T.; Sueki, K.

2008-01-01

A multi-nuclide AMS system on the 12UD Pelletron tandem accelerator at the University of Tsukuba (Tsukuba AMS system) has been able to measure environmental levels of long lived radioisotopes of 14 C, 26 Al, 36 Cl and 129 I by employing a molecular pilot beam method. In addition, we have been developing 32 Si and 41 Ca AMS systems for future research programs. Recently, the performance of 36 Cl AMS was improved in AMS technique. The standard deviation is within ±2%, and the background is better than 5 x 10 -15 for the 36 Cl/Cl ratio. At present, our Tsukuba AMS research group has focused its activities especially on the measurement of 36 Cl. We have measured more than 500 samples in year including earth and environmental sciences with the Tsukuba AMS system. A detailed description of the Tsukuba AMS system is given and earth and environmental applications are also described briefly. (author)

A decade of AMS at University of Georgia

Energy Technology Data Exchange (ETDEWEB)

Culp, Randy, E-mail: rculp@uga.edu [Center for Applied Isotope Studies, University of Georgia, Athens, GA (United States); Noakes, John; Cherkinsky, Alex; Ravi Prasad, G.V.; Dvoracek, Doug [Center for Applied Isotope Studies, University of Georgia, Athens, GA (United States)

2013-01-15

In a span of 10 years, University of Georgia's Center for Applied Isotope Studies (CAIS) has transformed itself from principally a liquid scintillation counting (LSC) laboratory to one conducting thousands of accelerator mass spectrometry (AMS) and stable isotope ratio analysis (SIRA) annually. After receiving the first of the NEC compact AMS units in the United States, the CAIS began to meet the demand for {sup 14}C analysis outside the normal realm of most radiocarbon dating laboratories. With industry's support, isotope research continued on an already developing natural products program to authenticate materials origin and process of formation. The CAIS's AMS allowed for the detection of synthetic materials in milligram quantities rather than gram quantities required by LSC and allowed new compound specific SIRA techniques to be directed toward compound specific {sup 14}C measurement. By 2005 the CAIS was one of only a few laboratories accredited to determine bio-base content in industrial fuels and products by both AMS and LSC following ASTM D6866-10 [1]. Since 2001, when our first sample was analyzed by AMS method, both radiocarbon and natural products sample numbers have increased steadily. The advantages of AMS analysis in overall efficiency, cost savings, accuracy, and precision, are detailed here in a review of analytical precision for radiocarbon and natural products analyzed over 10 years of AMS operation. Comparisons are made between natural products and bio-based materials analyzed by both AMS and LSC. Although high precision is not required to authenticate natural products, for the purpose of product comparison with regard to degree of naturalness accurate and precise {sup 14}C measurement is shown to be achievable by both methods.

Experimentally measured susceptibility to peer influence and adolescent sexual behavior trajectories : A preliminary study

NARCIS (Netherlands)

Choukas-Bradley, S.; Giletta, M.; Widman, L.; Cohen, G.L.; Prinstein, M.J.

2014-01-01

A performance-based measure of peer influence susceptibility was examined as a moderator of the longitudinal association between peer norms and trajectories of adolescents' number of sexual intercourse partners. Seventy-one 9th grade adolescents (52% female) participated in an experimental "chat

Developments towards a fully automated AMS system

International Nuclear Information System (INIS)

Steier, P.; Puchegger, S.; Golser, R.; Kutschera, W.; Priller, A.; Rom, W.; Wallner, A.; Wild, E.

2000-01-01

The possibilities of computer-assisted and automated accelerator mass spectrometry (AMS) measurements were explored. The goal of these efforts is to develop fully automated procedures for 'routine' measurements at the Vienna Environmental Research Accelerator (VERA), a dedicated 3-MV Pelletron tandem AMS facility. As a new tool for automatic tuning of the ion optics we developed a multi-dimensional optimization algorithm robust to noise, which was applied for 14 C and 10 Be. The actual isotope ratio measurements are performed in a fully automated fashion and do not require the presence of an operator. Incoming data are evaluated online and the results can be accessed via Internet. The system was used for 14 C, 10 Be, 26 Al and 129 I measurements

A novel tertiary prep-HPLC method for the isolation of single amino acids for AMS-radiocarbon measurement.

Science.gov (United States)

Fernandes, Ricardo; Koudelka, Tomas; Tholey, Andreas; Dreves, Alexander

2017-07-15

AMS-radiocarbon measurements of amino acids can potentially provide more reliable radiocarbon dates than bulk collagen analysis. Nonetheless, the applicability of such an approach is often limited by the low-throughput of existing isolation methods and difficulties in determining the contamination introduced during the separation process. A novel tertiary prep-HPLC amino acid isolation method was developed that relies on the combustion of eluted material without requiring any additional chemical steps. Amino acid separation was carried out using a gradient mix of pure water and phosphoric acid with an acetonitrile step in-between runs to remove hydrophobic molecules from the separation column. The amount of contaminant carbon and its 14 C content were determined from two-point measurements of collagen samples of known 14 C content. The amount of foreign carbon due to the isolation process was estimated at 4±1μg and its 14 C content was 0.43±0.01 F 14 C. Radiocarbon values corrected for carbon contamination have only a minor increase in uncertainties. For Holocene samples, this corresponds to an added uncertainty typically smaller than 10 14 Cyears. The developed method can be added to routine AMS measurements without implying significant operational changes and offers a level of measurement uncertainty that is suitable for many archaeological, ecological, environmental, and biological applications. Copyright © 2017. Published by Elsevier B.V.

Tectono-sedimentary analysis using the anisotropy of magnetic susceptibility: a study of the terrestrial and freshwater Neogene of the Orava Basin

Science.gov (United States)

Łoziński, Maciej; Ziółkowski, Piotr; Wysocka, Anna

2017-10-01

The Orava Basin is an intramontane depression filled with presumably fine-grained sediments deposited in river, floodplain, swamp and lake settings. The basin infilling constitutes a crucial record of the neoalpine evolution of the Inner/Outer Carpathian boundary area since the Neogene, when the Jurassic-Paleogene basement became consolidated, uplifted and eroded. The combination of sedimentological and structural studies with anisotropy of magnetic susceptibility (AMS) measurements provided an effective tool for recognition of terrestrial environments and deformations of the basin infilling. The lithofacies-oriented sampling and statistical approach to the large dataset of AMS specimens were utilized to define 12 AMS facies based on anisotropy degree (P) and shape (T). The AMS facies allowed a distinction of sedimentary facies ambiguous for classical methods, especially floodplain and lacustrine sediments, as well as revealing their various vulnerabilities to tectonic modification of AMS. A spatial analysis of facies showed that tuffites along with lacustrine and swamp deposits were generally restricted to marginal and southern parts of the basin. Significant deformations were noticed at basin margins and within two intrabasinal tectonic zones, which indicated the tectonic activity of the Pieniny Klippen Belt after the Middle Miocene. The large southern area of the basin recorded consistent N-NE trending compression during basin inversion. This regional tectonic rearrangement resulted in a partial removal of the southernmost basin deposits and shaped the basin's present-day extent.

Towards the definition of AMS facies in the deposits of pyroclastic density currents

Science.gov (United States)

Ort, M.H.; Newkirk, T.T.; Vilas, J.F.; Vazquez, J.A.; Ort, M.H.; Porreca, Massimiliano; Geissman, J.W.

2014-01-01

Anisotropy of magnetic susceptibility (AMS) provides a statistically robust technique to characterize the fabrics of deposits of pyroclastic density currents (PDCs). AMS fabrics in two types of pyroclastic deposits (small-volume phreatomagmatic currents in the Hopi Buttes volcanic field, Arizona, USA, and large-volume caldera-forming currents, Caviahue Caldera, Neuquén, Argentina) show similar patterns. Near the vent and in areas of high topographical roughness, AMS depositional fabrics are poorly grouped, with weak lineations and foliations. In a densely welded proximal ignimbrite, this fabric is overprinted by a foliation formed as the rock compacted and deformed. Medial deposits have moderate–strong AMS lineations and foliations. The most distal deposits have strong foliations but weak lineations. Based on these facies and existing models for pyroclastic density currents, deposition in the medial areas occurs from the strongly sheared, high-particle-concentration base of a density-stratified current. In proximal areas and where topography mixes this denser base upwards into the current, deposition occurs rapidly from a current with little uniformity to the shear, in which particles fall and collide in a chaotic fashion. Distal deposits are emplaced by a slowing or stalled current so that the dominant particle motion is vertical, leading to weak lineation and strong foliation.

A.c. susceptibility measurements in the presence of d.c. magnetic fields for Nd-Ba-Cu-O superconductors

International Nuclear Information System (INIS)

Watahiki, M.; Murakami, M.; Yoo, S.I.

1997-01-01

We report the temperature and magnetic field dependence of the complex a.c. susceptibility with bias d.c. magnetic fields for melt-processed Nd-Ba-Cu-O superconductor. The onset temperature (T onset ) of the real part of a.c. susceptibility shifted to a lower temperature with increasing d.c. magnetic field. The superconducting transition temperature (T c ) determined by d.c. magnetization measurements did not shift appreciably to a lower-temperature region with increasing d.c. magnetic field. The distinction between T onset and T c indicates that the a.c. susceptibility measurements detect the energy dissipation generated by the motion of flux lines. We have also measured flux profiles and found that there was no appreciable change in flux penetration below and above the peak field, which suggests that the peak effect in Nd-Ba-Cu-O is not due to the phase transition in the flux line lattice. (author)

Magnetic susceptibility measurement of solid oxygen at pressures up to 3.3 GPa

Energy Technology Data Exchange (ETDEWEB)

Mito, M., E-mail: mitoh@tobata.isc.kyutech.ac.jp; Yamaguchi, S.; Tsuruda, H.; Deguchi, H. [Faculty of Engineering, Kyushu Institute of Technology, Kitakyushu 804-8550 (Japan); Ishizuka, M. [Renovation Center of Instruments for Science Education and Technology, Osaka University, Toyonaka 560-8531 (Japan)

2014-01-07

The magnetic susceptibility of solid oxygen had long been observed only in the restricted pressure region below 0.8 GPa. We succeeded in extending the pressure region up to 3.3 GPa by clamping condensed oxygen in the sample chamber of a miniature diamond anvil cell and measuring the dc magnetic susceptibility using a superconducting quantum interference device magnetometer. In this experiment, the well-known α–β and β–γ transitions are observed in the phase diagram, suggesting consistency with the previous results of X-ray and Raman studies. In addition, a new magnetic anomaly is observed in the β phase.

Strain-dependent susceptibility for hypertension in mice resides in the natural killer gene complex

NARCIS (Netherlands)

Taherzadeh, Zhila; VanBavel, Ed; de Vos, Judith; Matlung, Hanke L.; van Montfrans, Gert; Brewster, Lizzy M.; Seghers, Leonard; Quax, Paul H. A.; Bakker, Erik N. T. P.

2010-01-01

Taherzadeh Z, VanBavel E, de Vos J, Matlung HL, van Montfrans G, Brewster LM, Seghers L, Quax PH, Bakker EN. Strain-dependent susceptibility for hypertension in mice resides in the natural killer gene complex. Am J Physiol Heart Circ Physiol 298: H1273-H1282, 2010. First published February 12, 2010;

AMS. A powerful tool for probing nucleosynthesis via long-lived radionuclides

International Nuclear Information System (INIS)

Wallner, A.; Golser, R.; Kutschera, W.; Priller, A.; Steier, P.; Kaeppeler, F.

2005-01-01

The potential of accelerator mass spectrometry (AMS) will be demonstrated on typical radionuclides of interest with half-lives between some years and up to hundred million years. The Vienna Environmental Research Accelerator (VERA) represents a state-of-the-art AMS facility which provides the ability for quantifying nuclides over the whole mass range. At VERA, AMS is used for quantifying long-lived radionuclides within a wide range of applications - from archaeology to astrophysics. Lack of information on cross section data exists for a list of nuclides pointed out by nuclear data requests. The potential of AMS as a powerful tool for probing nucleosynthesis will be demonstrated by means of some prime examples. Recent developments in the technique of AMS will be highlighted and some applications of AMS in astrophysics will be discussed. In addition, an overview on detection limits, measurement precision as well as the recent measurement program at VERA for quantifying such long-lived radionuclides will be presented. (author)

Latest AMS Results on elementary particles in cosmic rays

Science.gov (United States)

Kounine, Andrei; AMS Collaboration

2017-01-01

AMS-02 is a particle physics detector collecting data on the International Space Station since May 2011. Precision measurements of all elementary charged cosmic ray particles have been performed by AMS using a data sample of 85 billion cosmic ray events collected during the first five years of operations on the Station. The latest AMS results on the fluxes and flux ratios of the elementary cosmic ray particles are presented. They show unique features that require accurate theoretical interpretation as to their origin, be it from dark matter collisions or new astrophysical sources. On behalf of the AMS Collaboration.

Experimentally Measured Susceptibility to Peer Influence and Adolescent Sexual Behavior Trajectories: A Preliminary Study

Science.gov (United States)

Choukas-Bradley, Sophia; Giletta, Matteo; Widman, Laura; Cohen, Geoffrey L.; Prinstein, Mitchell J.

2014-01-01

A performance-based measure of peer influence susceptibility was examined as a moderator of the longitudinal association between peer norms and trajectories of adolescents' number of sexual intercourse partners. Seventy-one 9th grade adolescents (52% female) participated in an experimental "chat room" paradigm involving…

Measurement of 239Pu in urine samples at ultra-trace levels using a 1 MV compact AMS system

International Nuclear Information System (INIS)

Hernandez-Mendoza, H.; Chamizo, E.; Yllera, A.; Garcia-Leon, M.; Delgado, A.

2010-01-01

Routine bioassay monitoring of Pu intake in exposed workers of research and nuclear industry is usually performed by alpha spectrometry. This technique involves large sample volumes of urine and time-consuming preparative and counting protocols. Compact accelerator mass spectrometry (AMS) facilities make feasible the determination of ultra low-level Pu activity concentrations and Pu isotopic ratios in biological samples (blood, urine and feces), being a rapid and cost-effective measurement technique. The plutonium results in urine samples presented here have been obtained on the 1 MV compact AMS system sited at the Centro Nacional de Aceleradores (CNA), in Seville, Spain. In this work, a different methodological approach has been developed alternative to the 'classical' preparation of urine samples for alpha spectrometry. The procedure avoids the Pu precipitation step, and involves acid sample evaporation and acid digestion in a microwave oven. Finally, purification of plutonium was achieved by using chromatography columns filled up with BioRad AG1X2 anion exchange resin (Bio-Rad Laboratories Inc.). The total time needed for analysis is about 10 h, unlike the 'classical' methods based on alpha spectrometry which need about 1 week. At present, it has been demonstrated that this method allows quantifying 239 Pu activity concentrations in urine of, at least, 30 μBq (13 fg 239 Pu). We can conclude that the procedure would be suitable to perform in vitro routine bioassay measurements. Moreover, the innovative application of AMS opens new and interesting analytical alternatives in this field.

Modification of analytical method for measurement of 239Pu, 240Pu and 241Am in sediment and sea water

International Nuclear Information System (INIS)

Syarbaini; Tarigan, C.; Rustam, M.F.

1997-01-01

Modification of analytical method for measurement of 239 Pu, 240 Pu and 241 Am in sediment and sea water have been conducted. This study is to develop a method for separation of 239 Pu, 240 Pu and 241 Am from 100-300 g of sediment and 100-200 l of sea water samples. Most of the methods described in the literature are to separation of '2 39 Pu, '2 40 Pu and 241 Am from 20-50 g of sediment and 30-100 l of sea water samples. By this method, 239,240 Pu and 241 Am were concentrated using the coprecipitation of CaC 2 O 4 and Fe (OH) 3 . Plutonium-242 and Curium-244 were used as tracer to determine chemical recovery. The result of analysis of some sediment samples showed that the chemical recoveries were respectively obtained in the range of 59.7 to 72.6% with average of 66.2 % for 242 Pu and 72.0 % to 85.5 % with average 78.8 % for 244 Cm. Analysis of some sea water samples were obtained in the range of 67 % to 78 % with average 73.9 % for 242 Pu and 74.0 % to 90.0 % with average 84.2 % for '2 42 Cm. This method was tested by the IAEA marine sediment, the result was excellent agreement with the IAEA certified sediment. It could be suggested that the developed analytical method is suitable to analyze the low level 239 Pu, 240 Pu and 241 Am in sediment and sea water samples (author)

Determination of 241Am in reindeer bone

International Nuclear Information System (INIS)

Tahtinen, P.; Hakanen, M.; Jaakkola, T.; Nikula, A.

1978-01-01

The purpose of this work was to develop a procedure to separate americium from other alpha active nuclides present in reindeer bone samples, especially 228 Th and its daughter nuclides. The 241 Am-spectrum of a reindeer bone sample analyzed using the proposed method is given. The α-spectrum was measured one week after electrodeposition. The absence of the alpha peak of 224 Ra, the daughter nuclide of 228 Th, indicates that no 228 Th was electrodeposited onto the platinum disc. Four reindeer bone samples were analyzed for 241 Am using the method developed. The 241 Am/ 239 240 Pu activity ratio in reindeer bone was 0.9 :- 0.4. These results indicate that compared to plutonium, americium is accumulated in reindeer bone more heavily than in liver. All 241 Am values presented are concentrations at the time of radioassay, and no correction has been made for the ingrowth of 241 Am formed by the decay of 241 Pu during stockpilling. However, all 241 Am determinations were made 1 to 3 yrs after sample collection, and thus the corrections due to the ingrowth can be considered slight. About 60% of plutonium body burden is located in liver and 20% in skeleton. The activity ratio 241 Am/ 239 240 Pu in these animals was about 0.2 and 1.0 in liver and skeleton, respectively. This indicates that about 60% of the 241 Am body burden is located in skeleton and about 30% in liver. It can be roughly estimated that the whole-body activity of 241 Am is thus about 40% of the 239 240 Pu body burden

Alpha and conversion electron spectroscopy of {sup 238,239}Pu and {sup 241}Am and alpha-conversion electron coincidence measurements

Energy Technology Data Exchange (ETDEWEB)

Dion, Michael P., E-mail: michael.dion@pnnl.gov; Miller, Brian W.; Warren, Glen A.

2016-09-11

A technique to determine the isotopic constituents of a mixed actinide sample has been proposed by a coincident alpha-conversion electron measurement. This presents a unique signature to allow the unfolding of isotopes that possess overlapping alpha particle energy and reduce backgrounds of an unseparated sample. The work presented here are results of conversion electron spectroscopy of {sup 241}Am, {sup 238}Pu and {sup 239}Pu using a dual-stage peltier-cooled 25 mm{sup 2} silicon drift detector and alpha spectroscopy with a passivated ion implanted planar silicon detector. The conversion electron spectra were evaluated from 20–55 keV based on fits to the dominant conversion electron emissions, which allowed the relative conversion electron emission intensities to be determined. These measurements provide crucial singles spectral information and calibration to aid in the coincident measurement approach. Furthermore, an alpha-conversion electron spectrometer was assembled using the silicon based detectors described and results of a coincident spectrum analysis is reported for {sup 241}Am.

Evidence of 11-year solar cycles in tree rings from 1010 to 1110 AD - Progress on high precision AMS measurements

Energy Technology Data Exchange (ETDEWEB)

Guettler, D., E-mail: guettler@phys.ethz.ch [Laboratory of Ion Beam Physics, ETH Zurich, HPK G31, Schafmattstrasse 20, 8093 Zurich (Switzerland); Wacker, L. [Laboratory of Ion Beam Physics, ETH Zurich, HPK G31, Schafmattstrasse 20, 8093 Zurich (Switzerland); Kromer, B.; Friedrich, M. [Heidelberg Academy of Sciences, 69120 Heidelberg (Germany); Institute of Botany, University of Hohenheim, 70593 Stuttgart (Germany); Synal, H.-A. [Laboratory of Ion Beam Physics, ETH Zurich, HPK G31, Schafmattstrasse 20, 8093 Zurich (Switzerland)

2013-01-15

Oak tree rings from Southern Germany covering the AD 1010-1110 years have been analyzed for radiocarbon with accelerator mass spectrometry (AMS) at the laboratory at ETH Zurich. High-precision measurements with a precision down to 12 years radiocarbon age and a time resolution of 2 years aimed to identify modulations of the {sup 14}C concentration in tree ring samples caused by the 11 years solar cycles, a feature that so far is not visible in the IntCal calibration curve. Our results are in good agreement with the current calibration curve IntCal09. However, we observed an offset in radiocarbon age of 25-40 years towards older values. An evaluation of our sample preparation, that included variations of e.g.: chemicals, test glasses and processing steps did not explain this offset. The numerous measurements using the AMS-MICADAS system validated its suitability for high precision measurements with high repeatability.

Correlation of PET and AMS analyses for early kinetics of 2-fluoro-2-deoxyglucose (FDG)

International Nuclear Information System (INIS)

Minamimoto, Ryogo; Hamabe, Yoshimi; Miyaoka, Teiji; Theeraladanon, Chumpol; Oka, Takashi; Matsui, Takao; Inoue, Tomio

2010-01-01

The draft of the guidelines for microdosing in clinical trials was published in Japan in 2008 following the guidelines of the European Medicines Agency (EMEA) and the Food and Drug Administration (FDA). It recommends utilizing accelerator mass spectrometry (AMS), liquid chromatography/mass spectrometry (LC/MS/MS), and positron emission tomography (PET) for monitoring drug metabolites in preclinical studies. In this study, we clarified the correlation in measuring result between PET and AMS. The AMS measurement was undergone by using AMS system of Institute of Accelerator Analysis Ltd. (IAA, Kawasaki, Japan). First the back ground 14 C level of blood in mice was measured by AMS. Second, we clarified the relationship between AMS and PET by using 2-fluoro-2-deoxyglucose (FDG). The correlation coefficient (r) of the measurements using PET ( 18 F-FDG) and AMS ( 14 C-FDG) were quite high at 0.97 (Y = 7.54E - 05X + 0.02, p 18 F-FDG was nearly identical with that of 14 C-FDG. These results indicate that the AMS analysis has excellent correlation with the PET method.

Correlation of PET and AMS analyses for early kinetics of 2-fluoro-2-deoxyglucose (FDG)

Science.gov (United States)

Minamimoto, Ryogo; Hamabe, Yoshimi; Miyaoka, Teiji; Theeraladanon, Chumpol; Oka, Takashi; Matsui, Takao; Inoue, Tomio

2010-04-01

The draft of the guidelines for microdosing in clinical trials was published in Japan in 2008 following the guidelines of the European Medicines Agency (EMEA) and the Food and Drug Administration (FDA). It recommends utilizing accelerator mass spectrometry (AMS), liquid chromatography/mass spectrometry (LC/MS/MS), and positron emission tomography (PET) for monitoring drug metabolites in preclinical studies. In this study, we clarified the correlation in measuring result between PET and AMS. The AMS measurement was undergone by using AMS system of Institute of Accelerator Analysis Ltd. (IAA, Kawasaki, Japan). First the back ground 14C level of blood in mice was measured by AMS. Second, we clarified the relationship between AMS and PET by using 2-fluoro-2-deoxyglucose (FDG). The correlation coefficient ( r) of the measurements using PET ( 18F-FDG) and AMS ( 14C-FDG) were quite high at 0.97 ( Y = 7.54 E - 05 X + 0.02, p blood clearance profile of 18F-FDG was nearly identical with that of 14C-FDG. These results indicate that the AMS analysis has excellent correlation with the PET method.

Identification and antifungal susceptibility of Candida species isolated from the urine of patients in a university hospital in Brazil

Directory of Open Access Journals (Sweden)

Gláucia Moreira Espíndola Lima

2017-12-01

Full Text Available ABSTRACT The aim of this study was to identify Candida spp. isolated from candiduria episodes at a tertiary hospital in the Midwest region of Brazil, and to determine their susceptibility profiles to antifungal compounds. From May 2011 to April 2012, Candida spp. isolated from 106 adult patients with candiduria admitted to the University Hospital of the Federal University of Mato Grosso do Sul were evaluated. Both, species identification and susceptibility testing with fluconazole-FLC, voriconazole-VRC, and amphotericin B-AmB were carried out using the Vitek 2. To discriminate species of the C. parapsilosis complex, a RAPD-PCR technique using the RPO2 primer was performed. From the total of 106 isolates, 42 (39.6% C. albicans and 64 (60.4% Candida non-albicans (CNA - 33 C. tropicalis, 18 C. glabrata, 5 C. krusei, 4 C. parapsilosis sensu stricto, 2 C. kefyr, 1 C. lusitaniae, and 1 C. guilliermondii were identified. All isolates were susceptible to AmB and VRC, whereas all C. glabrata isolates presented either resistance (5.6% or dose-dependent susceptibility (94.4% to FLC. The study of Candida spp. and their resistance profiles may help in tailoring more efficient therapeutic strategies for candiduria.

A decade of AMS at the University of Georgia

Science.gov (United States)

Culp, Randy; Noakes, John; Cherkinsky, Alex; Ravi Prasad, G. V.; Dvoracek, Doug

2013-01-01

In a span of 10 years, the University of Georgia’s Center for Applied Isotope Studies (CAIS) has transformed itself from principally a liquid scintillation counting (LSC) laboratory to one conducting thousands of accelerator mass spectrometry (AMS) and stable isotope ratio analysis (SIRA) annually. After receiving the first of the NEC compact AMS units in the United States, the CAIS began to meet the demand for 14C analysis outside the normal realm of most radiocarbon dating laboratories. With industry’s support, isotope research continued on an already developing natural products program to authenticate materials origin and process of formation. The CAIS’s AMS allowed for the detection of synthetic materials in milligram quantities rather than gram quantities required by LSC and allowed new compound specific SIRA techniques to be directed toward compound specific 14C measurement. By 2005 the CAIS was one of only a few laboratories accredited to determine bio-base content in industrial fuels and products by both AMS and LSC following ASTM D6866-10 [1]. Since 2001, when our first sample was analyzed by AMS method, both radiocarbon and natural products sample numbers have increased steadily. The advantages of AMS analysis in overall efficiency, cost savings, accuracy, and precision, are detailed here in a review of analytical precision for radiocarbon and natural products analyzed over 10 years of AMS operation. Comparisons are made between natural products and bio-based materials analyzed by both AMS and LSC. Although high precision is not required to authenticate natural products, for the purpose of product comparison with regard to degree of naturalness accurate and precise 14C measurement is shown to be achievable by both methods.

Measurement of fast neutron induced fission cross sections of 232Th, 238U, 237Np and 243Am

International Nuclear Information System (INIS)

Kanda, Kazutaka; Sato, Osamu; Yoshida, Kazuo; Imaruoka, Hiromitsu; Terayama, Hiromichi; Yoshida, Masashi; Hirakawa, Naohiro

1984-01-01

Neutron induced fission cross sections of 232 Th, 238 U, 237 Np and 243 Am relative to 235 U were measured in the energy range from 1.5 to 6.6 MeV. The present results are compared with experimental results of others and evaluated data in JENDL-2 and ENDF/B-IV. (author)

Corrosion Performance of Friction Stir Linear Lap Welded AM60B Joints

Science.gov (United States)

Kish, J. R.; Birbilis, N.; McNally, E. M.; Glover, C. F.; Zhang, X.; McDermid, J. R.; Williams, G.

2017-11-01

A corrosion investigation of friction stir linear lap welded AM60B joints used to fabricate an Mg alloy-intensive automotive front end sub-assembly was performed. The stir zone exhibited a slightly refined grain size and significant break-up and re-distribution of the divorced Mg17Al12 (β-phase) relative to the base material. Exposures in NaCl (aq) environments revealed that the stir zone was more susceptible to localized corrosion than the base material. Scanning vibrating electrode technique measurements revealed differential galvanic activity across the joint. Anodic activity was confined to the stir zone surface and involved initiation and lateral propagation of localized filaments. Cathodic activity was initially confined to the base material surface, but was rapidly modified to include the cathodically-activated corrosion products in the filament wake. Site-specific surface analyses revealed that the corrosion observed across the welded joint was likely linked to variations in Al distribution across the surface film/metal interface.

Nuclear data measurements in 3x592 GBq 241Am-Be neutron cell

International Nuclear Information System (INIS)

2010-01-01

The aim of this study is to present the results of the activities carried out within the scope of the Nuclear Data Measurements in 3x592 GBq Am-Be Neutron Cell project. The study covers the establishment of neutron irradiation systems, neutron and gamma dose rate evaluations in and around the laboratory, performance measurements of neutron irradiation systems, measurements of thermal, epithermal and fast neutron flux, gamma spectrometer efficiency calibrations, fast neutron fission product yield measurements for fertile nuclides ( 2 32Th and 2 38U), cross section measurements for fast neutron threshold detectors, gamma ray intensity measurements of the nuclides in uranium decay chain, elemental detection limit measurements and the half life measurement of short-lived isotopes. First of all, an irradiation geometry, which enables optimum irradiation, was designed for an irradiation system of 3 2 41Am-Be sources with 592 GBq activity each. Paraffin was chosen in order to slow down the source neutrons. An equilateral quadrangle with 70 cm side length and 60 cm height was used as paraffin moderator. Experimentally, it was determined that paraffin with approximately 3.5 cm thickness slows down to maximum thermal neutron flux of 2 41Am-Be neutrons. Paraffin block was placed on the base of the source room. In order to determine the positions of thermal and fast neutron irradiations, indium wires were irradiated with 5 mm intervals vertically parallel to the neutron sources in thermal and fast neutron irradiation cells. The position of maximum thermal and fast neutron fluxes is 61.5 cm for the thermal neutron irradiation cells and 69 cm for the fast neutron irradiation cell, from the top of the irradiation pipes down. One of the most important parameters of nuclear data measurements is the counting efficiency of the gamma spectrometer used for each counting geometry. For this reason, the detector efficiencies for the related counting geometries need to be measured

Resource for the Development of Biomedical Accelerator Mass Spectrometry (AMS)

Energy Technology Data Exchange (ETDEWEB)

Turteltaub, K. W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bench, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Buchholz, B. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Enright, H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kulp, K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); McCartt, A. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Malfatti, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ognibene, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Loots, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Stewart, B. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2016-04-08

The NIH Research Resource for Biomedical AMS was originally funded at Lawrence Livermore National Laboratory in 1999 to develop and apply the technology of accelerator mass spectrometry (AMS) in broad- based biomedical research. The Resource’s niche is to fill needs for ultra high sensitivity quantitation when isotope-labeled agents are used. The Research Resource’s Technology Research and Development (TR&D) efforts will focus on the needs of the biomedical research community in the context of seven Driving Biomedical Projects (DBPs) that will drive the Center’s technical capabilities through three core TR&Ds. We will expand our present capabilities by developing a fully integrated HPLC AMS to increase our capabilities for metabolic measurements, we will develop methods to understand cellular processes and we will develop and validate methods for the application of AMS in human studies, which is a growing area of demand by collaborators and service users. In addition, we will continue to support new and ongoing collaborative and service projects that require the capabilities of the Resource. The Center will continue to train researchers in the use of the AMS capabilities being developed, and the results of all efforts will be widely disseminated to advance progress in biomedical research. Towards these goals, our specific aims are to:1.) Increase the value and information content of AMS measurements by combining molecular speciation with quantitation of defined macromolecular isolates. Specifically, develop and validate methods for macromolecule labeling, characterization and quantitation.2.) Develop and validate methods and strategies to enable AMS to become more broadly used in human studies. Specifically, demonstrate robust methods for conducting pharmacokinetic/pharmacodynamics studies in humans and model systems.3.) Increase the accessibility of AMS to the Biomedical research community and the throughput of AMS through direct coupling to separatory

Resource for the Development of Biomedical Accelerator Mass Spectrometry (AMS)

Energy Technology Data Exchange (ETDEWEB)

Tuerteltaub, K. W. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bench, G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Buchholz, B. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Enright, H. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Kulp, K. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Loots, G. G. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); McCartt, A. D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Malfatti, M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Ognibene, T. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Stewart, B. J. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-03-21

The NIH Research Resource for Biomedical AMS was originally funded at Lawrence Livermore National Laboratory in 1999 to develop and apply the technology of accelerator mass spectrometry (AMS) in broad- based biomedical research. The Resource’s niche is to fill needs for ultra high sensitivity quantitation when isotope-labeled agents are used. The Research Resource’s Technology Research and Development (TR&D) efforts will focus on the needs of the biomedical research community in the context of seven Driving Biomedical Projects (DBPs) that will drive the Center’s technical capabilities through three core TR&Ds. We will expand our present capabilities by developing a fully integrated HPLC AMS to increase our capabilities for metabolic measurements, we will develop methods to understand cellular processes and we will develop and validate methods for the application of AMS in human studies, which is a growing area of demand by collaborators and service users. In addition, we will continue to support new and ongoing collaborative and service projects that require the capabilities of the Resource. The Center will continue to train researchers in the use of the AMS capabilities being developed, and the results of all efforts will be widely disseminated to advance progress in biomedical research. Towards these goals, our specific aims are to:1.) Increase the value and information content of AMS measurements by combining molecular speciation with quantitation of defined macromolecular isolates. Specifically, develop and validate methods for macromolecule labeling, characterization and quantitation.2.) Develop and validate methods and strategies to enable AMS to become more broadly used in human studies. Specifically, demonstrate robust methods for conducting pharmacokinetic/pharmacodynamics studies in humans and model systems.3.) Increase the accessibility of AMS to the Biomedical research community and the throughput of AMS through direct coupling to separatory

Actinide AMS at DREAMS

Energy Technology Data Exchange (ETDEWEB)

Khojasteh, Nasrin B.; Merchel, Silke; Rugel, Georg; Scharf, Andreas; Ziegenruecker, Rene [HZDR, Dresden (Germany); Pavetich, Stefan [HZDR, Dresden (Germany); ANU, Canberra (Australia)

2016-07-01

Radionuclides such as {sup 236}U and {sup 239}Pu were introduced into the environment by atmospheric nuclear weapon tests, reactor accidents (Chernobyl, Fukushima), releases from nuclear reprocessing facilities (Sellafield, La Hague), radioactive waste disposal, and accidents with nuclear devices (Palomares, Thule) [1]. Accelerator Mass Spectrometry (AMS) is the most sensitive method to measure these actinides. The DREsden AMS (DREAMS) facility is located at a 6 MV accelerator, which is shared with ion beam analytics and implantation users, preventing major modifications of the accelerator and magnetic analyzers. DREAMS was originally designed for {sup 10}Be, {sup 26}Al, {sup 36}Cl, {sup 41}Ca, and {sup 129}I. To modify the system for actinide AMS, a Time-of-Flight (TOF) beamline at the high-energy side has been installed and performance tests are on-going. Ion beam and detector simulations are carried out to design a moveable ionization chamber. Especially, the detector window and anode dimensions have to be optimized. This ionization chamber will act as an energy detector of the system and its installation is planned as closely as possible to the stop detector of the TOF beamline for highest detection efficiency.

Cosmic ray anisotropy searches with AMS-02

Energy Technology Data Exchange (ETDEWEB)

Zeissler, Stefan; Gebauer, Iris; Trumpf, Ricarda [Karlsruher Institut fuer Technologie (KIT) (Germany)

2016-07-01

The Alpha Magnetic Spectrometer (AMS-02) is a state-of-the-art particle detector designed to operate as an external module on the International Space Station (ISS). In this unique space environment cosmic particles can be measured with high precision over an energy range from GeV up to TeV. The AMS collaboration provided precise measurements of the electron and positron fluxes, which indicate an additional source of positrons among the various cosmic particles. Possible candidates for this source are local pulsars, a local source of positrons produced in proton-gas interactions or dark matter annihilation. In the first two cases a possible anisotropy in the electrons and positrons incoming direction at Earth might be detectable. To determine the level of isotropy the measured data is compared to reference maps, which simulate the measurement of an isotropic sky. A common choice of reference maps are proton count maps or shuffled maps, which redistribute measured incoming directions over the whole measuring time. Both choices lead to difficulties in the reconstruction of a marginal signal with a big expansion over the galactic sky as it would be the case for charged cosmic particles. We developed a method to construct reference maps based on fundamental detector characteristics such as the lifetime and the geometric acceptance. Using this we are able to reconstruct the isotropic sky as it would be seen by the detector. We demonstrate the performance of the method using AMS-02 data.

Correlation of PET and AMS analyses for early kinetics of 2-fluoro-2-deoxyglucose (FDG)

Energy Technology Data Exchange (ETDEWEB)

Minamimoto, Ryogo, E-mail: ryogom@yokohama-cu.ac.j [Department of Radiology, Graduate School of Medicine, Yokohama City University, Yokohama (Japan); Hamabe, Yoshimi; Miyaoka, Teiji [Institute of Accelerator Analysis (IAA) Ltd., Kawasaki (Japan); Theeraladanon, Chumpol; Oka, Takashi [Department of Radiology, Graduate School of Medicine, Yokohama City University, Yokohama (Japan); Matsui, Takao [Institute of Accelerator Analysis (IAA) Ltd., Kawasaki (Japan); Inoue, Tomio [Department of Radiology, Graduate School of Medicine, Yokohama City University, Yokohama (Japan)

2010-04-15

The draft of the guidelines for microdosing in clinical trials was published in Japan in 2008 following the guidelines of the European Medicines Agency (EMEA) and the Food and Drug Administration (FDA). It recommends utilizing accelerator mass spectrometry (AMS), liquid chromatography/mass spectrometry (LC/MS/MS), and positron emission tomography (PET) for monitoring drug metabolites in preclinical studies. In this study, we clarified the correlation in measuring result between PET and AMS. The AMS measurement was undergone by using AMS system of Institute of Accelerator Analysis Ltd. (IAA, Kawasaki, Japan). First the back ground {sup 14}C level of blood in mice was measured by AMS. Second, we clarified the relationship between AMS and PET by using 2-fluoro-2-deoxyglucose (FDG). The correlation coefficient (r) of the measurements using PET ({sup 18}F-FDG) and AMS ({sup 14}C-FDG) were quite high at 0.97 (Y = 7.54E - 05X + 0.02, p < 0.001). The blood clearance profile of {sup 18}F-FDG was nearly identical with that of {sup 14}C-FDG. These results indicate that the AMS analysis has excellent correlation with the PET method.

AMS using 14UD Pelletron at TIFR, Mumbai: present status and future prospects

International Nuclear Information System (INIS)

Surendran, P.; Gupta, A.K.; Nair, J.P.; Mahata, K.; Shrivastava, A.; Yadav, M.L.; Sparrow, H.; Thomas, R.G.; Bhagwat, P.V.; Kailas, S.; Kale, R.M.

2011-01-01

The AMS (Accelerator Mass Spectrometry) is a versatile tool employed in multidisciplinary programmes. The AMS programme at the BARC-TIFR 14UD Pelletron accelerator has been initiated with major emphasis on the determination of 36 Cl concentration in environment in general and water samples in particular. Preliminary measurements related to detection of 129 I have been carried out in recent past. The system used for AMS measurement is based on a 14 MV Tandem Accelerator. In this paper, the status and future prospects of AMS programme at BARC-TIFR Pelletron Accelerator Facility are presented

47 CFR 27.63 - Disturbance of AM broadcast station antenna patterns.

Science.gov (United States)

2010-10-01

... immediate vicinity of AM broadcast stations are responsible for measures necessary to correct disturbance of... the FCC for the AM station, if the disturbance occurred as a result of such construction or...

Results of Am isotopic ratio analysis in irradiated MOX fuels

Energy Technology Data Exchange (ETDEWEB)

Koyama, Shin-ichi; Osaka, Masahiko; Mitsugashira, Toshiaki; Konno, Koichi [Power Reactor and Nuclear Fuel Development Corp., Oarai, Ibaraki (Japan). Oarai Engineering Center; Kajitani, Mikio

1997-04-01

For analysis of a small quantity of americium, it is necessary to separate from curium which has similar chemical property. As a chemical separation method for americium and curium, the oxidation of americium with pentavalent bismuth and subsequent co-precipitation of trivalent curium with BIP O{sub 4} were applied to analyze americium in irradiated MOX fuels which contained about 30wt% plutonium and 0.9wt% {sup 241}Am before irradiation and were irradiated up to 26.2GWd/t in the experimental fast reactor Joyo. The purpose of this study is to measure isotopic ratio of americium and to evaluate the change of isotopic ratio with irradiation. Following results are obtained in this study. (1) The isotopic ratio of americium ({sup 241}Am, {sup 242m}Am and {sup 243}Am) can be analyzed in the MOX fuels by isolating americium. The isotopic ratio of {sup 242m}Am and {sup 243}Am increases up to 0.62at% and 0.82at% at maximum burnup, respectively, (2) The results of isotopic analysis indicates that the contents of {sup 241}Am decreases, whereas {sup 242m}Am, {sup 243}Am increase linearly with increasing burnup. (author)

High-frequency, transient magnetic susceptibility of ferroelectrics

Science.gov (United States)

Grimes, Craig A.

1996-10-01

A significant high-frequency magnetic susceptibility was measured both in weakly polarized and nonpolarized samples of barium titanate, lead zirconate titanate, and carnauba wax. Magnetic susceptibility measurements were made from 10 to 500 MHz using a thin film permeameter at room temperature; initial susceptibilities ranged from 0.1 to 2.5. These values are larger than expected for paramagnets and smaller than expected for ferromagnets. It was found that the magnetic susceptibility decreases rapidly with exposure to the exciting field. The origin of the magnetic susceptibility is thought to originate with the applied time varying electric field associated with the susceptibility measurements. An electric field acts to rotate an electric dipole, creating a magnetic quadrupole if the two moments are balanced, and a net magnetic dipole moment if imbalanced. It is thought that local electrostatic fields created at ferroelectric domain discontinuities associated with grain boundaries create an imbalance in the anion rotation that results in a net, measurable, magnetic moment. The origin of the magnetic aftereffect may be due to the local heating of the material through the moving charges associated with the magnetic moment.

Evidence of 11-year solar cycles in tree rings from 1010 to 1110 AD – Progress on high precision AMS measurements

International Nuclear Information System (INIS)

Güttler, D.; Wacker, L.; Kromer, B.; Friedrich, M.; Synal, H.-A.

2013-01-01

Oak tree rings from Southern Germany covering the AD 1010–1110 years have been analyzed for radiocarbon with accelerator mass spectrometry (AMS) at the laboratory at ETH Zurich. High-precision measurements with a precision down to 12 years radiocarbon age and a time resolution of 2 years aimed to identify modulations of the 14 C concentration in tree ring samples caused by the 11 years solar cycles, a feature that so far is not visible in the IntCal calibration curve. Our results are in good agreement with the current calibration curve IntCal09. However, we observed an offset in radiocarbon age of 25–40 years towards older values. An evaluation of our sample preparation, that included variations of e.g.: chemicals, test glasses and processing steps did not explain this offset. The numerous measurements using the AMS-MICADAS system validated its suitability for high precision measurements with high repeatability.

Measurement of fission cross section with pure Am-243 sample using lead slowing-down spectrometer

Energy Technology Data Exchange (ETDEWEB)

Kobayashi, Katsuhei; Yamamoto, Shuji; Kai, T.; Fujita, Yoshiaki; Yamamoto, Hideki; Kimura, Itsuro [Kyoto Univ. (Japan); Shinohara, Nobuo

1997-03-01

By making use of back-to-back type double fission chambers and a lead slowing-down spectrometer coupled to an electron linear accelerator, the fission cross section for the {sup 243}Am(n,f) reaction has been measured relative to that for the {sup 235}U(n,f) reaction in the energy range from 0.1 eV to 10 keV. The measured result was compared with the evaluated nuclear data appeared in ENDF/B-VI and JENDL-3.2, whose evaluated data were broadened by the energy resolution function of the spectrometer. General agreement was seen between the evaluated data and the measurement except that the ENDF/B-VI data were lower in the range from 15 to 60 eV and that the JENDL-3.2 data seemed to be lower above 100 eV. (author)

New measurement technique of ductility curve for ductility-dip cracking susceptibility in Alloy 690 welds

Energy Technology Data Exchange (ETDEWEB)

Kadoi, Kota, E-mail: kadoi@hiroshima-u.ac.jp [Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527 (Japan); Uegaki, Takanori; Shinozaki, Kenji; Yamamoto, Motomichi [Graduate School of Engineering, Hiroshima University, 1-4-1 Kagamiyama, Higashi-Hiroshima, Hiroshima 739-8527 (Japan)

2016-08-30

The coupling of a hot tensile test with a novel in situ observation technique using a high-speed camera was investigated as a high-accuracy quantitative evaluation method for ductility-dip cracking (DDC) susceptibility. Several types of Alloy 690 filler wire were tested in this study owing to its susceptibility to DDC. The developed test method was used to directly measure the critical strain for DDC and high temperature ductility curves with a gauge length of 0.5 mm. Minimum critical strains of 1.3%, 4.0%, and 3.9% were obtained for ERNiCrFe-7, ERNiCrFe-13, and ERNiCrFe-15, respectively. The DDC susceptibilities of ERNiCrFe-13 and ERNiCrFe-15 were nearly the same and quite low compared with that of ERNiCrFe-7. This was likely caused by the tortuosity of the grain boundaries arising from the niobium content of around 2.5% in the former samples. Besides, ERNiCrFe-13 and ERNiCrFe-15 indicated higher minimum critical strains even though these specimens include higher content of sulfur and phosphorus than ERNiCrFe-7. Thus, containing niobium must be more effective to improve the susceptibility compared to sulfur and phosphorous in the alloy system.

New measurement technique of ductility curve for ductility-dip cracking susceptibility in Alloy 690 welds

International Nuclear Information System (INIS)

Kadoi, Kota; Uegaki, Takanori; Shinozaki, Kenji; Yamamoto, Motomichi

2016-01-01

The coupling of a hot tensile test with a novel in situ observation technique using a high-speed camera was investigated as a high-accuracy quantitative evaluation method for ductility-dip cracking (DDC) susceptibility. Several types of Alloy 690 filler wire were tested in this study owing to its susceptibility to DDC. The developed test method was used to directly measure the critical strain for DDC and high temperature ductility curves with a gauge length of 0.5 mm. Minimum critical strains of 1.3%, 4.0%, and 3.9% were obtained for ERNiCrFe-7, ERNiCrFe-13, and ERNiCrFe-15, respectively. The DDC susceptibilities of ERNiCrFe-13 and ERNiCrFe-15 were nearly the same and quite low compared with that of ERNiCrFe-7. This was likely caused by the tortuosity of the grain boundaries arising from the niobium content of around 2.5% in the former samples. Besides, ERNiCrFe-13 and ERNiCrFe-15 indicated higher minimum critical strains even though these specimens include higher content of sulfur and phosphorus than ERNiCrFe-7. Thus, containing niobium must be more effective to improve the susceptibility compared to sulfur and phosphorous in the alloy system.

47 CFR 22.371 - Disturbance of AM broadcast station antenna patterns.

Science.gov (United States)

2010-10-01

... construct or modify towers in the immediate vicinity of AM broadcast stations are responsible for measures... radiation parameters specified by the FCC for the AM station, if the disturbance occurred as a result of...

Magnetic susceptibility measurement using 3D NMR

Czech Academy of Sciences Publication Activity Database

Marcon, P.; Bartušek, Karel; Kořínek, Radim

2011-01-01

Roč. 24, Suppl. 1 (2011), s. 381-382 ISSN 0968-5243. [ESMRMB 2011 Congress. 06.10.2011-08.10.2011, Leipzig] R&D Projects: GA ČR GAP102/11/0318 Institutional research plan: CEZ:AV0Z20650511 Keywords : MRI * artifact correction * magnetic susceptibility * gradient echo Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

241Am distribution and retention in pregnant mice, in their offspring and in non-pregnant mice: comparison between continuous Am administration and single injection

International Nuclear Information System (INIS)

Huevel, R. Van Den; Vander Plaetse, F.; Leppens, H.; Schoeters, G.

1992-01-01

Pregnant BALB/c mice and age and sex matched nulliparous controls were contaminated with 241 Am (13 kBq per mouse). Five days after the termination of contamination, 241 Am incorporation was measured in the tissues of adults and in the liver an the femur of newborn and one-month-old mice. Pregnancy resulted in higher 241 Am concentrations in bone but lower concentrations in the liver of the mothers. Protracted administration of 241 Am compared to a single injection resulted in a lower concentration of 241 Am in the livers of pregnant mice, their nulliparous controls and from newborn mice. The higher 241 Am concentration in the femur at birth after protected exposure before 14 days of gestation compared to protracted exposure after 14 days of gestation could reflect the increased placental transfer of 241 Am with advancing gestational age. Radiation doses to the femur were estimated between 4 and 20 mGy. Haemopoietic changes were noticed at these dose levels in all groups until at least 6 months after birth. (author)

Development of the Lund AMS system and the evaluation of a new AMS detection technique

International Nuclear Information System (INIS)

Wiebert, A.

1995-09-01

This thesis is based on work at the Lund Pelletron accelerator facility in order to improve the accuracy and efficiency of the Lund Accelerator Mass Spectrometry (AMS) system. To obtain high accuracy, all measurements are performed relative to a standard of known activity. Charge state distributions have been obtained for a number of isotopes: 9 Be, 12 C, 13 C, 16 O, 19 F, 27 Al, 35 Cl, 48 Ti and 58 Ni order to improve the transmission through the system and to reduce the isotopic fractionation in the measurements. For carbon, charge states distributions were obtained both under foil and gas stripping. The pressure profile of the Lund Pelletron system has been calculated, both under foil and gas stripping, to make possible to perform transmission calculations for a carbon beam. These results were used to design a new terminal stripper of the accelerator system. A new ion source has, during the last few years, been constructed providing a multiple sample wheel, enabling more accurate relative measurements and also providing more efficient measurements, due to a higher beam current. A new detection technique suitable for AMS measurements on heavier radionuclides, such as 36 Cl, 44 Ti and 59 Ni, has been evaluated and detection limits for 59 Ni have been derived. 59 refs, 13 figs

Unravelling mycorrhiza-induced wheat susceptibility to the English grain aphid Sitobion avenae

Science.gov (United States)

Simon, Amma L.; Wellham, Peter A. D.; Aradottir, Gudbjorg I.; Gange, Alan C.

2017-04-01

Arbuscular mycorrhizal (AM) fungi are root symbionts that can increase or decrease aphid growth rates and reproduction, but the reason by which this happens is unknown. To investigate the underlying mechanisms of this interaction, we examined the effect of AM fungi on the English Grain aphid (Sitobion avenae) development, reproduction, attraction, settlement and feeding behaviour on two naturally susceptible varieties Triticum aestivum (L.) variety Solstice and T. monococcum MDR037, and two naturally resistant lines, T. monococcum MDR045 and MDR049. Mycorrhizal colonisation increased the attractiveness of T. aestivum var. Solstice to aphids, but there was no effect on aphid development on this variety. Using the Electrical Penetration Graph (EPG) technique, we found that mycorrhizal colonisation increased aphid phloem feeding on T. monococcum MDR037 and MDR045, colonisation also increased growth rate and reproductive success of S. avenae on these varieties. Mycorrhizas increased vascular bundle size, demonstrating that these fungi can influence plant anatomy. We discuss if and how this could be related to an enhanced success rate in phloem feeding in two varieties. Overall, we present and discuss how mycorrhizal fungi can affect the feeding behaviour of S. avenae in wheat, inducing susceptibility in a resistant variety.

Charge determination of nuclei with the AMS-02 silicon tracker

OpenAIRE

Alpat, B.; G. Ambrosi; Azzarello, P.; Battiston, R.; Bene, P.; Bertucci, B.; Bizzaglia, S.; Bizzarri, M.; Blasko, S.; Bourquin, M.; Cortina Gil, Eduardo

2005-01-01

The silicon tracker of the AMS-02 detector measures the trajectory in three dimensions of electrons, protons and nuclei to high precision in a dipole magnetic field and thus measures their rigidity (momentum over charge) and the sign of their charge. In addition, it measures the specific energy loss of charged particles to determine the charge magnitude. Ladders from the AMS-02 tracker have been exposed to ion beams at CERN and GSI to study their response to nuclei from helium up to the iron ...

Measurement of complex RF susceptibility using a series Q-meter

International Nuclear Information System (INIS)

Kisselev, Yu.F.; Dulya, C.M.; Niinikoski, T.O.

1995-01-01

In this paper we have for the first time derived closed form expressions for the nuclear magnetic susceptibility in terms of the series Q-meter output voltage. We discuss the corrections involved in determining nuclear polarization from NMR signals by using the deuteron and proton spin systems as examples. Deuteron signals are shown to exhibit a false asymmetry, while proton signals have substantial shape distortions. Moreover, for the first time the importance of making a phase correction is demonstrated. We conclude that the series Q-meter with real part detection is not sufficient to produce an output voltage from which the nuclear susceptibility can be determined. An additional phase-sensitive detector is proposed for obtaining the imaginary part of the signal required for unambiguous extraction of the complex RF susceptibility. ((orig.))

AMS of heavy radionuclides at ANTARES: status and plans

Energy Technology Data Exchange (ETDEWEB)

Smith, A.M.; Fink, D.; Hotchkis, M.A.C.; Lawson, E.M.; Tuniz, C. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

1996-12-31

Long-lived radioisotopes are produced in the environment by cosmic ray interactions, natural radioactivity and through the use of nuclear technologies. Detection of trace amounts of anthropogenic isotopes by accelerator mass spectrometry (AMS) is a means of monitoring the safe operation of nuclear facilities and the presence of nuclear activities, however for heavy isotopes such measurements are difficult. This paper discusses the approach taken at ANTARES in developing AMS measurement capability for the actinides and summarises the current status of the project. 6 refs., 1 fig.

AMS of heavy radionuclides at ANTARES: status and plans

Energy Technology Data Exchange (ETDEWEB)

Smith, A M; Fink, D; Hotchkis, M A.C.; Lawson, E M; Tuniz, C [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

1997-12-31

Long-lived radioisotopes are produced in the environment by cosmic ray interactions, natural radioactivity and through the use of nuclear technologies. Detection of trace amounts of anthropogenic isotopes by accelerator mass spectrometry (AMS) is a means of monitoring the safe operation of nuclear facilities and the presence of nuclear activities, however for heavy isotopes such measurements are difficult. This paper discusses the approach taken at ANTARES in developing AMS measurement capability for the actinides and summarises the current status of the project. 6 refs., 1 fig.

AmWeb: a novel interactive web tool for antimicrobial resistance surveillance, applicable to both community and hospital patients.

Science.gov (United States)

Ironmonger, Dean; Edeghere, Obaghe; Gossain, Savita; Bains, Amardeep; Hawkey, Peter M

2013-10-01

Antimicrobial resistance (AMR) is recognized as one of the most significant threats to human health. Local and regional AMR surveillance enables the monitoring of temporal changes in susceptibility to antibiotics and can provide prescribing guidance to healthcare providers to improve patient management and help slow the spread of antibiotic resistance in the community. There is currently a paucity of routine community-level AMR surveillance information. The HPA in England sponsored the development of an AMR surveillance system (AmSurv) to collate local laboratory reports. In the West Midlands region of England, routine reporting of AMR data has been established via the AmSurv system from all diagnostic microbiology laboratories. The HPA Regional Epidemiology Unit developed a web-enabled database application (AmWeb) to provide microbiologists, pharmacists and other stakeholders with timely access to AMR data using user-configurable reporting tools. AmWeb was launched in the West Midlands in January 2012 and is used by microbiologists and pharmacists to monitor resistance profiles, perform local benchmarking and compile data for infection control reports. AmWeb is now being rolled out to all English regions. It is expected that AmWeb will become a valuable tool for monitoring the threat from newly emerging or currently circulating resistant organisms and helping antibiotic prescribers to select the best treatment options for their patients.

RICH – A new AMS facility at the Royal Institute for Cultural Heritage, Brussels, Belgium

Energy Technology Data Exchange (ETDEWEB)

Boudin, Mathieu; Van Strydonck, Mark; Brande, Tess van den [Royal Institute for Cultural Heritage, Jubelpark 1, 1000 Brussels (Belgium); Synal, Hans-Arno; Wacker, Luckas [Laboratory of Ion Beam Physics, ETH Zurich, 8093 Zurich (Switzerland)

2015-10-15

Since 1989 the radiocarbon dating lab has their own graphitization system for {sup 14}C AMS dating but RICH (Royal Institute for Cultural Heritage) did not possess their own AMS and measurements were carried out in collaboration with other AMS facilities. In April 2013 the Micadas (Mini Carbon Dating System) AMS was installed at RICH in Brussels and after 1.5 year operation the high stability and performance of the Micadas can be demonstrated by repeated analyses of primary standard OXA II and secondary standards. Results of unknown samples measured on the RICH–Micadas and on other AMS systems are in good agreement.

A new 14C AMS facility at IUAC, New Delhi

International Nuclear Information System (INIS)

Kumar, Pankaj; Ojha, S.; Sharma, R.; Gargari, S.; Joshi, R.; Chopra, S.; Kanjilal, D.

2015-01-01

A new state of art Accelerator Mass Spectrometry (AMS) facility for 14 C has been developed at IUAC. This facility is based on the 0.5 MV Pelletron accelerator and an Automated Graphitization Equipment (AGE). In addition to the 14 C measurements, this system has the capability to perform 10 Be and 26 AI measurements also. The system is called XCAMS i.e., Compact, Accelerator Mass Spectrometer eXtended for 10 Be and 26 AI. A detailed description of the newly developed AMS facility and the recent measurements will be discussed

The Top-of-Instrument corrections for nuclei with AMS on the Space Station

Science.gov (United States)

Ferris, N. G.; Heil, M.

2018-05-01

The Alpha Magnetic Spectrometer (AMS) is a large acceptance, high precision magnetic spectrometer on the International Space Station (ISS). The top-of-instrument correction for nuclei flux measurements with AMS accounts for backgrounds due to the fragmentation of nuclei with higher charge. Upon entry in the detector, nuclei may interact with AMS materials and split into fragments of lower charge based on their cross-section. The redundancy of charge measurements along the particle trajectory with AMS allows for the determination of inelastic interactions and for the selection of high purity nuclei samples with small uncertainties. The top-of-instrument corrections for nuclei with 2 < Z ≤ 6 are presented.

Magnetic susceptibility and magnetic resonance measurements of the moisture content and hydration condition of a magnetic mixture material

International Nuclear Information System (INIS)

Tsukada, K.; Kusaka, T.; Saari, M. M.; Takagi, R.; Sakai, K.; Kiwa, T.; Bito, Y.

2014-01-01

We developed a magnetic measurement method to measure the moisture content and hydration condition of mortar as a magnetic mixture material. Mortar is a mixture of Portland cement, sand, and water, and these materials exhibit different magnetic properties. The magnetization–magnetic field curves of these components and of mortars with different moisture contents were measured, using a specially developed high-temperature-superconductor superconducting quantum interference device. Using the differences in magnetic characteristics, the moisture content of mortar was measured at the ferromagnetic saturation region over 250 mT. A correlation between magnetic susceptibility and moisture content was successfully established. After Portland cement and water are mixed, hydration begins. At the early stage of the hydration/gel, magnetization strength increased over time. To investigate the magnetization change, we measured the distribution between bound and free water in the mortar in the early stage by magnetic resonance imaging (MRI). The MRI results suggest that the amount of free water in mortar correlates with the change in magnetic susceptibility

sup 241 Am distribution and retention in pregnant mice, in their offspring and in non-pregnant mice: comparison between continuous Am administration and single injection

Energy Technology Data Exchange (ETDEWEB)

Huevel, R. Van Den; Vander Plaetse, F.; Leppens, H.; Schoeters, G. (Centre d' Etude de l' Energie Nucleaire, Mol (Belgium))

1992-01-01

Pregnant BALB/c mice and age and sex matched nulliparous controls were contaminated with {sup 241}Am (13 kBq per mouse). Five days after the termination of contamination, {sup 241}Am incorporation was measured in the tissues of adults and in the liver an the femur of newborn and one-month-old mice. Pregnancy resulted in higher {sup 241}Am concentrations in bone but lower concentrations in the liver of the mothers. Protracted administration of {sup 241}Am compared to a single injection resulted in a lower concentration of {sup 241}Am in the livers of pregnant mice, their nulliparous controls and from newborn mice. The higher {sup 241}Am concentration in the femur at birth after protected exposure before 14 days of gestation compared to protracted exposure after 14 days of gestation could reflect the increased placental transfer of {sup 241}Am with advancing gestational age. Radiation doses to the femur were estimated between 4 and 20 mGy. Haemopoietic changes were noticed at these dose levels in all groups until at least 6 months after birth. (author).

The AMS-02 experiment status

International Nuclear Information System (INIS)

Oliva, A.

2011-01-01

The Alpha Magnetic Spectrometer (AMS) is a high-energy physics experiment built to operate in space. The prototype of the AMS detector was AMS-01, fown in1998 on-board of the space shuttle Discovery (missionSTS-91). Starting from the experience acquired in the high successful AMS-01 mission the detector AMS-02 has been designed improving the AMS-01 energetic range, geometric acceptance and particle identifcation capabilities. In 2010 the AMS-02 detector has been validated for the space/scientifc operations by means of a wide test campaign(including beam tests, TVT test and EMI test). A major change in the design of AMS-02 has been decided after the thermo-vacuum test to extend as much aspossible the endurance of the experiment, profiting also of the extended endurance of the International Space Station (ISS) program toward 2020. The final AMS-02 configuration has been integrated during summer 2010, then tested on the H8 beam-line at CERN, and finally delivered to the launch site (Kennedy Space Center, Florida) at the end of August. AMS-02 is planned to be installed on the International Space Station in 2011 by the space shuttle Endeavour (mission STS-134).

Design and test results of the AMS RICH detector

CERN Document Server

Casadei, D.

2002-01-01

The AMS-02 detector will operate for at least 3 years on the International Space Station, measuring cosmic ray spectra at about 400 km above sea level over a wide range of geomagnetic latitude. The proximity focusing ring imaging \\v{C}erenkov counter of AMS-02 will measure the particle velocity $\\beta$ with $\\approx 0.1%$ uncertainty, making possible to discriminate Beryllium isotopes up to about 15 GeV/nucl. In addition its charge measurement will allow to study the elemental composition of cosmic rays up to Iron. A prototype of the RICH detector was tested with cosmic rays and on a ion beam accelerated by SPS, at CERN (October 2002).

Susceptibility Testing by Polymerase Chain Reaction DNA Quantitation: A Method to Measure Drug Resistance of Human Immunodeficiency Virus Type 1 Isolates

Science.gov (United States)

Eron, Joseph J.; Gorczyca, Paul; Kaplan, Joan C.; D'Aquila, Richard T.

1992-04-01

Polymerase chain reaction (PCR) DNA quantitation (PDQ) susceptibility testing rapidly and directly measures nucleoside sensitivity of human immunodeficiency virus type 1 (HIV-1) isolates. PCR is used to quantitate the amount of HIV-1 DNA synthesized after in vitro infection of peripheral blood mononuclear cells. The relative amounts of HIV-1 DNA in cell lysates from cultures maintained at different drug concentrations reflect drug inhibition of virus replication. The results of PDQ susceptibility testing of 2- or 3-day cultures are supported by assays measuring HIV-1 p24 antigen production in supernatants of 7- or 10-day cultures. DNA sequence analyses to identify mutations in the reverse transcriptase gene that cause resistance to 3'-azido-3'-deoxythymidine also support the PDQ results. With the PDQ method, both infectivity titration and susceptibility testing can be performed on supernatants from primary cultures of peripheral blood mononuclear cells. PDQ susceptibility testing should facilitate epidemiologic studies of the clinical significance of drug-resistant HIV-1 isolates.

Detection of superparamagnetic particles in soils developed on basalts using frequency- and amplitude-dependent magnetic susceptibility

Science.gov (United States)

Grison, H.; Petrovsky, E.; Kapicka, A.

2016-12-01

In rock, soil and environmental studies dealing with magnetic methods, the frequency-dependent magnetic susceptibility (κFD%) is parameter generally accepted as a tool for identification of ultrafine superparamagnetic (SP) particles. This parameter became an indicator of pedogenic magnetic fraction (increased pedogenesis). Despite the number of studies using this parameter, knowledge about threshold values of κFD% is not clear enough and this parameter may be misinterpreted. Moreover, in strongly magnetic soils, magnetic signal of the SP (mostly pedogenic) minerals may be masked by dominant lithological signal, carried by coarse-grain mineral fraction; therefore, influence of pedogenesis is hard to detect. The aim of this contribution is to compare results in determination of ultrafine SP magnetic particles in soils determined using different instruments: (a) Bartington MS2B dual-frequency meter, and (b) more sensitive AGICO Kappameter MFK1-FA. The values of the κFD % obtained by the Bartington MS2B varied from 0.9 to 5.8% (mass-specific magnetic susceptibility from 119 to 1533 × 10-8 m3/kg) while the AGICO MFK1-FA varied from 3.7 to 8.2% (mass-specific magnetic susceptibility from 295 to 1843 × 10-8 m3/kg). Although both instruments suggest significant portion of SP magnetic particles, the results can't be interpreted using the generally accepted threshold values based on Bartington data. However, our results suggest that relation between the mass-specific magnetic susceptibility and κFD% along whole soil profile may serve as suitable tool in discriminating between lithogenic and pedogenic control of magnetic fraction in the soil profile. Moreover, we propose new concept of identification of SP particles, based on field-dependent magnetic susceptibility. Its behaviour shows distinct features with significant change at amplitudes of about 100 A/m. Below this value, susceptibility decreases with increasing amplitude, reflecting saturation of magnetization due

Behavior of 241Am in fast reactor systems - a safeguards perspective

International Nuclear Information System (INIS)

Beddingfield, David H.; Lafleur, Adrienne M.

2009-01-01

Advanced fuel-cycle developments around the world currently under development are exploring the possibility of disposing of 241 Am from spent fuel recycle processes by burning this material in fast reactors. For safeguards practitioners, this approach could potentially complicate both fresh- and spent-fuel safeguards measurements. The increased (α,n) production in oxide fuels from the 241 Am increases the uncertainty in coincidence assay of Pu in MOX assemblies and will require additional information to make use of totals-based neutron assay of these assemblies. We have studied the behavior of 241 Am-bearing MOX fuel in the fast reactor system and the effect on neutron and gamma-ray source-terms for safeguards measurements. In this paper, we will present the results of simulations of the behavior of 241 Am in a fast breeder reactor system. Because of the increased use of MOX fuel in thermal reactors and advances in fuel-cycle designs aimed at americium disposal in fast reactors, we have undertaken a brief study of the behavior of americium in these systems to better understand the safeguards impacts of these new approaches. In this paper we will examine the behavior of 241 Am in a variety of nuclear systems to provide insight into the safeguards implications of proposed Am disposition schemes.

Imaging AMS

Energy Technology Data Exchange (ETDEWEB)

Freeman, S.P.H.T. [Univ. of Oxford (United Kingdom)]|[Lawrence Livermore National Lab., CA (United States); Ramsey, C.B.; Hedges, R.E.M. [Univ. of Oxford (United Kingdom)

1993-12-01

The benefits of simultaneous high effective mass resolution and large spectrometer acceptance that accelerator mass spectrometry has afforded the bulk analysis of material samples by secondary ion mass spectrometry may also be applied to imaging SIMS. The authors are exploring imaging AMS with the addition to the Oxford {sup 14}C-AMS system of a scanning secondary ion source. It employs a sub micron probe and a separate Cs flood to further increase the useful ion yield. The source has been accommodated on the system by directly injecting sputtered ions into the accelerator without mass analysis. They are detected with a range of devices including new high-bandwidth detectors. Qualitative mass spectra may be easily generated by varying only the post-accelerator analysis magnet. Selected ion signals may be used for imaging. In developing the instrument for bioscience research the authors are establishing its capability for measuring the lighter elements prevalent in biological tissue. Importantly, the machine can map the distributions of radiocarbon labeled compounds with an efficiency of about 1{per_thousand}. A background due to misidentification of non-{sup 14}C ions as a result of the reduced ion mass filtering is too small to hinder high magnification microscopy.

Development of the Lund AMS system and the evaluation of a new AMS detection technique

Energy Technology Data Exchange (ETDEWEB)

Wiebert, A

1995-09-01

This thesis is based on work at the Lund Pelletron accelerator facility in order to improve the accuracy and efficiency of the Lund Accelerator Mass Spectrometry (AMS) system. To obtain high accuracy, all measurements are performed relative to a standard of known activity. Charge state distributions have been obtained for a number of isotopes: {sup 9}Be, {sup 12}C, {sup 13}C, {sup 16}O, {sup 19}F, {sup 27}Al, {sup 35}Cl, {sup 48}Ti and {sup 58}Ni order to improve the transmission through the system and to reduce the isotopic fractionation in the measurements. For carbon, charge states distributions were obtained both under foil and gas stripping. The pressure profile of the Lund Pelletron system has been calculated, both under foil and gas stripping, to make possible to perform transmission calculations for a carbon beam. These results were used to design a new terminal stripper of the accelerator system. A new ion source has, during the last few years, been constructed providing a multiple sample wheel, enabling more accurate relative measurements and also providing more efficient measurements, due to a higher beam current. A new detection technique suitable for AMS measurements on heavier radionuclides, such as {sup 36}Cl,{sup 44}Ti and {sup 59}Ni, has been evaluated and detection limits for {sup 59}Ni have been derived. 59 refs, 13 figs.

General concept and present status of the AMS - project

International Nuclear Information System (INIS)

Stan-Sion, C.; Plostinaru, D.; Catana, L.; Radulescu, M.; Marinescu, L.; Dima, R.

1998-01-01

The Institute of Nuclear Physics and Engineering, IFIN-HH, Bucharest started in 1996 the Construction Project for an AMS facility in Bucharest. The Project is supported by the German-Romanian scientific cooperation project RUM-013-97. In the frame of this project, scientific research, construction activities of electronic and mechanical devices and activities for calibration and optimization were performed. The activities in this year are concentrated on experimental tests and optimization of the AMS analysis procedure and on improving the tandem acceleration and transmission capability. These are as follows: - construction and tests of a high current sputter source, with spherical ionizer and automatic many-sample changer. Experimental tests and measurements of emittance and beam profile; - construction of the Injector Platform; - construction and tests of a Bragg - charged particle detector; - calibration and optimization experiments of the AMS ensemble. The AMS facility is based on the 8 MV - FN tandem accelerator and has the following main components: the AMS ion injector, a Wien - velocity filter, a 60 angle bending magnet and the particle detection system. For heavy particle detection we constructed a Bragg ionization chamber. This should be used for standard AMS measurements. A specific part of the AMS facility represents the AMS injector deck. The main components are: the high current sputter source, the analyzing double focusing magnet, two optical systems, a four-slit beam defining system in front of the analyzing magnet and a four-slit aperture with remote controlled Faraday cup (for beam current integration of stable isotopes) after the magnet. Finally, the pre-acceleration tube (40 kV) connects the ensemble to the ground potential of the accelerator beam line. For AMS measurements, the sputter ion source is able to provide both high beam current and small beam emittance. These characteristics are necessary in order to achieve high analyzing

AMS National Reachback Capability - New Tools for Helping Emergency Responders

International Nuclear Information System (INIS)

Wasiolek, Piotr; Lyons, Craig

2008-01-01

The Remote Sensing Laboratory's (RSL) Aerial Measuring System (AMS) is one of the emergency response assets belonging to the U.S. Department of Energy (DOE) National Nuclear Security Administration (NNSA). The AMS is used to detect, measure, and track radioactive material before and during emergencies to locate sources or determine contamination levels. Since September 11, 2001, increasing numbers of local, state, and federal entities have developed aerial radiation detection capabilities. NNSA has recognized a need by these entities for an AMS Reachback Center that would provide training and assistance on all aspects of AMS. The Center will assist local, state, and federal agencies in establishing the skills, resources, and training needed for a successful AMS regional operation. Beginning in January 2008, and continuing through April 2008, a pilot program was created in collaboration between NNSA and the U.S. Department of Homeland Security's Domestic Nuclear Detection Office (DNDO). The purpose of this collaboration was to provide aerial radiological surveillance and equipment technique training to local law enforcement offices in four major U.S. cities: Chicago, Washington DC, New York, and Los Angeles. The Mobile Aerial Radiological Surveillance (MARS) training curriculum was jointly developed by NNSA and DNDO headquarters and NNSA support teams. A total of 44 students participated in the training events held during this period. The positive reaction to this program has led to the establishment of the RSL as the headquarters for the National Aerial Measuring System Reachback (NAMSR) Center. The NAMSR Center will provide an AMS Home Team stand-by duty team for local, state, and federal agencies to discuss, plan, and analyze available data for aerial responses. An additional role of the Center will be to serve as the source of subject matter experts (SME) for the training of newly established aerial radiological monitoring assets. The purpose of this paper is to

AMS measurement of {sup 10}Be concentrations in marine sediments from Chile Trench at the TANDAR laboratory

Energy Technology Data Exchange (ETDEWEB)

Rodrigues, D., E-mail: darodrig@tandar.cnea.gov.ar [Departamento de Física Experimental, Laboratorio TANDAR, GIyA, Comisión Nacional de Energía Atómica, Av. Gral. Paz 1499, B1650KNA San Martín (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Arazi, A. [Departamento de Física Experimental, Laboratorio TANDAR, GIyA, Comisión Nacional de Energía Atómica, Av. Gral. Paz 1499, B1650KNA San Martín (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Fernández Niello, J.O. [Departamento de Física Experimental, Laboratorio TANDAR, GIyA, Comisión Nacional de Energía Atómica, Av. Gral. Paz 1499, B1650KNA San Martín (Argentina); CONICET, Av. Rivadavia 1917, C1033AAJ Buenos Aires (Argentina); Instituto de Investigación e Ingeniería Ambiental, Universidad Nacional de San Martín, 25 de Mayo y Francia, B1650BWA San Martín, Buenos Aires (Argentina); Martí, G.V. [Departamento de Física Experimental, Laboratorio TANDAR, GIyA, Comisión Nacional de Energía Atómica, Av. Gral. Paz 1499, B1650KNA San Martín (Argentina); and others

2017-03-15

The {sup 10}Be/{sup 9}Be ratios in marine sediments samples from the Southern Chile Trench have been measured using accelerator mass spectrometry (AMS). The samples were measured at the TANDAR accelerator, where the discrimination of the {sup 10}Be radionuclides was achieved by means of a passive absorber in front of an ionization chamber. This setup along with the high voltage available, provided a complete suppression of the {sup 10}B isobar interference. The obtained values for the {sup 10}Be concentrations, of the order of 10{sup 9} atoms/g, are the first {sup 10}Be measurements from the Southern Chile Trench and offer an excellent tracer to quantitatively study the recycling of sediments in Andean magmas.

Determination of the thermal conductivity of sediment rock from measurements on cuttings; Ermittlung der Gesteinswaermeleitfaehigkeit von Sedimentgesteinen aus Messungen am Bohrklein

Energy Technology Data Exchange (ETDEWEB)

Troschke, B; Burkhardt, H [Technische Univ. Berlin (Germany). Fachgebiet Angewandte Goephysik

1997-12-01

Due to high costs core recovery in many wells is strongly restricted. To determine thermal conductivity in these cases measurements on cuttings are necessary, since in situ measurements are expensive and protracted, too. Therefore cores from three hydrogeothermal wells of the north-east part of the German sedimentary basin were grinded to compare the results of measurements on cuttings with known values of thermal conductivity from the original cores. By a suitable model of the two-phase-system cuttings-water it is possible to calculate the thermal conductivity of the rock-matrix. On the basis of this value and a suitable rock-model an average thermal conductivity for the water saturated rock can be estimated. Certainly all influences of the texture (anisotropy, grain bond) and of the characteristics of the porespace (porosity, internal surface, saturation, permeability) are lost with measurements on cuttings. Therefore for the different systems cuttings-water and rock-porefluid as well as for different rock types different models are necessary. (orig.) [Deutsch] In vielen Bohrungen werden aus Kostengruenden keine Kerne gezogen. Fuer die Ermittlung der Waermeleitfaehigkeit koennen deshalb nur in-situ-Messungen, die ebenfalls zeit- und kostenintensiv sind, oder Messungen am Bohrklein herangezogen werden. Es wurden daher Kerne aus drei Hydrogeothermalbohrungen des nordostdeutschen Beckens aufgemahlen, um so vergleichende Messungen am `Bohrklein` aus Kernen mit bekannter Waermeleitfaehigkeit durzhzufuehren. Durch eine geeignete Modellvorstellung des Zwei-Phasen-Systems Bohrklein/Wasser laesst sich die Waermeleitfaehigkeit der Gesteinsmatrix bestimmen und aus dieser durch ein Gesteinsmodell auch eine mittlere Waermeleitfaehigkeit des wassergesaettigten Festgesteins berechnen. Klar ist, dass bei Messungen am Bohrklein Einfluesse, die durch Gefuege (Anisotropie, Kornbindung) und Porenraumeigenschaften (Porositaet, Saettigung, Permeabilitaet) hervorgerufen werden

Human cerebral blood volume measurements using dynamic contrast enhancement in comparison to dynamic susceptibility contrast MRI

Energy Technology Data Exchange (ETDEWEB)

Artzi, Moran [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Tel Aviv University, Sackler Faculty of Medicine, Tel Aviv (Israel); Liberman, Gilad; Vitinshtein, Faina; Aizenstein, Orna [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Nadav, Guy [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Tel Aviv University, Faculty of Engineering, Tel Aviv (Israel); Blumenthal, Deborah T.; Bokstein, Felix [Tel Aviv Sourasky Medical Center, Neuro-Oncology Service, Tel Aviv (Israel); Bashat, Dafna Ben [Tel Aviv Sourasky Medical Center, Functional Brain Center, The Wohl Institute for Advanced Imaging, Tel Aviv (Israel); Tel Aviv University, Sackler Faculty of Medicine and Sagol School of Neuroscience, Tel Aviv (Israel)

2015-07-15

Cerebral blood volume (CBV) is an important parameter for the assessment of brain tumors, usually obtained using dynamic susceptibility contrast (DSC) MRI. However, this method often suffers from low spatial resolution and high sensitivity to susceptibility artifacts and usually does not take into account the effect of tissue permeability. The plasma volume (v{sub p}) can also be extracted from dynamic contrast enhancement (DCE) MRI. The aim of this study was to investigate whether DCE can be used for the measurement of cerebral blood volume in place of DSC for the assessment of patients with brain tumors. Twenty-eight subjects (17 healthy subjects and 11 patients with glioblastoma) were scanned using DCE and DSC. v{sub p} and CBV values were measured and compared in different brain components in healthy subjects and in the tumor area in patients. Significant high correlations were detected between v{sub p} and CBV in healthy subjects in the different brain components; white matter, gray matter, and arteries, correlating with the known increased tissue vascularity, and within the tumor area in patients. This work proposes the use of DCE as an alternative method to DSC for the assessment of blood volume, given the advantages of its higher spatial resolution, its lower sensitivity to susceptibility artifacts, and its ability to provide additional information regarding tissue permeability. (orig.)

Alpha spectrum analysis of 241Am in the urine

International Nuclear Information System (INIS)

Qiu Yongmei; Yang Yong

2006-10-01

With 241 Am as indicator, americium in the urine was concentrated by the method of codeposition, then it was purified by the method of anion exchange, at last, the americium was electroplated. 241 Am in the urine was analysed by six channel low level alpha measuring instrument and Alpha Spectrometer. The results show that the recovering ratio is beyond 60% under the condition that the indicator added to the urine is at the level of mBq. So, 241 Am in the urine can be quantitatively analysed by this method, uncertainty of the result is under 40%, detection limit of the instrument is under 10 -4 Bq. (authors)

Measurement and analysis of the $^{241}$Am(n,$\\gamma$) cross section at the CERN n_TOF facility.

CERN Document Server

Fraval, Kevin

In the context of the current nuclear technology, the radiotoxicity of the spent fuel of a typical PWR reactor is dominated by minor actinides for times greater than 104 years. In particular, 241Am and its 432 years half-life is responsible for about half of the minor actinide content of a PWR spent fuel. This thesis work consisted in measuring and analysing the 241Am(n, ) cross section at the CERN n TOF facility. After selecting exclusively the events obtained with lead shielding in front of the C6D6 detectors, the amplitude-energy calibration has to be adjusted with time, by using a photon coming from the 27Al(,,p)30Si reaction. Histogram extraction included applying a weighting function (obtained by MCNP simulation), a dead time correction, and a normalization to the compound nucleus excitation energy. The background corrected spectra were normalized relatively to the 4.9 eV resonance on 197Au. Finally, the resonance analysis was performed using the SAMMY code. The extracted thermal value is 678±68 barns,...

Am(VI) Extraction Final Report: FY16

Energy Technology Data Exchange (ETDEWEB)

Mincher, Bruce Jay [Idaho National Lab. (INL), Idaho Falls, ID (United States); Grimes, Travis Shane [Idaho National Lab. (INL), Idaho Falls, ID (United States); Tillotson, Richard Dean [Idaho National Lab. (INL), Idaho Falls, ID (United States); Law, Jack Douglas [Idaho National Lab. (INL), Idaho Falls, ID (United States)

2016-08-01

This report summarizes activities related to hexavalent Am extraction for FY16, in completion of FCR&D Milestone M3FT-16IN030103027. Activities concentrated on three areas of research: 1) centrifugal contactor hot testing, 2) Am(VI) stability studies, and 3) alternative oxidant studies. A brief summary of each task follows. Hot Testing: A new engineering-scale oxidation and solvent extraction test bed was built at Idaho National Laboratory to allow for solvent extraction testing of minor actinide separation concepts. The test bed consists of an oxidation vessel, filtration apparatus, four, 3D printed, 2-cm diameter centrifugal contactors, feed/product vessels, and sample ports. This system replaced the previous 3 stage, 5-cm contactor test bed that was used for the initial testing in FY14. In the FY16 hot test, a feed simulant was spiked with 243Am and 139Ce and treated with 60 g/L sodium bismuthate for two hours to oxidize the Am(III) to Am(VI). This solution was then pumped through a filter and into the four-stage centrifugal contactor setup. The organic phase solvent formulation was 1 M diethylhexylbutyramide (DEHBA)/dodecane. The test showed that Am(VI) was produced by bismuthate oxidation and the residual oxidant was successfully filtered without back pressure buildup. Sixty-four percent of Am was extracted in the contactors using DEHBA. Both Am and Ce were quantitatively stripped by 0.1 M H2O2. Successful demonstration of the utility of small, printable contactors suggests that hot testing of separations concepts can now be conducted more often, since it is cheaper, generates less waste, and entails much less radcon risk than previous testing. Am(VI) stability: A rigorous examination of reagents was conducted to determine if contaminants could interfere with Am oxidation and extraction. An series of DAm measurements showed that bismuthate particle size, water source, acid quality, and DAAP batch or pre-treatment had little effect on extraction efficiency

Oxygen Chemical Diffusion Coefficients of (Pu,Am)O2 Fuels

International Nuclear Information System (INIS)

Watanabe, M.; Kato, M.; Matsumoto, T.

2015-01-01

Minor actinide (MA)-bearing MOX fuels have been developed as candidate fuels which are used in fast neutron spectrum cores such as sodium-cooled fast reactor (SFR) cores and experimental accelerator driven system (ADS) cores. Americium (Am) which is one of the MA elements significantly affects basic properties. It is known that Am content causes oxygen potential to increase and that influences irradiation behaviour such as fuel-cladding chemical interaction (FCCI) and chemical state of fission products. However, the effects of Am content on changes of basic properties are not clear. In this work, the oxygen chemical diffusion coefficients were calculated from measured data and the relationship between oxygen diffusion and oxygen potential of (Pu,Am)O 2-x was discussed. (authors)

The first year of operation of CologneAMS; performance and developments

Directory of Open Access Journals (Sweden)

Dewald A.

2013-12-01

Full Text Available In this contribution we report on the measurements performed so far at CologneAMS and on the quality which has been obtained for the isotopes 10Be, 14C and 26Al. We also describe the procedure developed to measure plutonium-isotopes at CologneAMS and first results for 239,240,242Pu are presented. In addition we report on modifications made on our new TOF device with beam profile capabilities.

Determination of Long-lived Radionuclides in the Environment using ICP-MS and AMS

DEFF Research Database (Denmark)

Hou, Xiaolin

2011-01-01

ICP-MS and AMS have been widely used for the measurement of radionuclides, especially long-lived radionculides. The new progress, major advantages of these two techniques and their major applications for measurement of important radionculides are summarized.......ICP-MS and AMS have been widely used for the measurement of radionuclides, especially long-lived radionculides. The new progress, major advantages of these two techniques and their major applications for measurement of important radionculides are summarized....

CologneAMS, a dedicated center for accelerator mass spectrometry in Germany

Energy Technology Data Exchange (ETDEWEB)

Dewald, A., E-mail: dewald@ikp.uni-koeln.de [CologneAMS, Institute of Nuclear Physics, University of Cologne (Germany); Heinze, S.; Jolie, J.; Zilges, A. [CologneAMS, Institute of Nuclear Physics, University of Cologne (Germany); Dunai, T.; Rethemeyer, J.; Melles, M.; Staubwasser, M. [Institute of Geology and Mineralogy, University of Cologne (Germany); Kuczewski, B. [Division of Nuclear Chemistry, University of Cologne (Germany); Richter, J. [Institute of Prehistoric Archaeology, University of Cologne (Germany); Radtke, U. [Institute of Geography, University of Cologne, Germany, Rectorate, University of Duisburg-Essen (Germany); Blanckenburg, F. von [GFZ, German Research Centre for Geosciences, Potsdam (Germany); Klein, M. [HVEE, Amersfoort (Netherlands)

2013-01-15

CologneAMS is a new centre for accelerator mass spectrometry (AMS) at University of Cologne. It has been funded by the German Research Foundation (DFG) to improve the experimental conditions especially for those German scientists that apply the AMS technique for their geologic, environmental, nuclear chemical, and nuclear astrophysical research. The new AMS-device has been built by High Voltage Engineering Europe (HVEE) and has been installed in the existing accelerator area of the Institute of Nuclear Physics. The AMS-facility is designed for the spectrometry of {sup 10}Be, {sup 14}C, {sup 26}Al, {sup 36}Cl, {sup 41}Ca, {sup 129}I in and heavy ions up to {sup 236}U and {sup 244}Pu. The central part of the AMS-facility is a 6 MV Tandetron Trade-Mark-Sign accelerator. Downstream of the high energy mass spectrometer an additional switching magnet is used as a further filter element which supplies also additional ports for future extensions of the detector systems. The current status of CologneAMS and the results of the first test measurements will be presented.

AMS-02 in space: physics results, overview, and challenges

Science.gov (United States)

Tomassetti, Nicola; AMS Collaboration

2015-08-01

The Alpha Magnetic Spectrometer (AMS-02) is a state of the art particle detector measuring cosmic rays (CRs) on the International Space Station (ISS) since May 19th 2011. AMS-02 identifies CR leptons and nuclei in the energy range from hundreds MeV to few TeV per nucleon. Several sub-detector systems allow for redundant particle identification with unprecedented precision, a powerful lepton-hadron separation, and a high purity of the antimatter signal. The new AMS-02 leptonic data from 1 to 500 GeV are presented and discussed. These new data indicate that new sources of CR leptons need to be included to describe the observed spectra at high energies. Explanations of this anomaly may be found either in dark-matter particles annihilation or in the existence of nearby astrophysical sources of e±. Future data at higher energies and forthcoming measurements on the antiproton spectrum and the boron-to-carbon ratio will be crucial in providing the discrimination among the different scenario.

Soil and water pollution studies from a waste site deposit in Bantama, Kumasi, Ghana using magnetic susceptibility measurements

International Nuclear Information System (INIS)

Hadi, M.; Preko, K.; Ashia, T.

2012-01-01

The magnetic susceptibility of soil and water samples from around the Uadara barracks waste site deposit in Bantama, a suburb of Kumasi was measured with the aim of investigating the potential threat of pollution to the soil, streams, fish ponds and other water sources at the site around Armed Forces Senior High School campus which shares the same premises with the barracks. The studied soil samples were picked from the near surface (∼10 cm depth) along profiles taken from the waste site towards the stream and the ponds. Again, water samples were picked along the stream and from ten (10) ponds aligned along the stream. Laboratory measurements of the magnetic susceptibility were done using the Bartington MS2 metre and the MS2B dual frequency sensor for the soil samples, and the MS2G sensor for the water samples. The soil samples from the site registered an average magnetic susceptibility of 180. 04 x 10 -5 SI whereas the water samples recorded an average of -2.3 x 10 -6 SI showing a significant increment in comparison with the standard water magnetic susceptibility of -9.04 x 10 -6 SI. Thus, not withstand the lithology of the area studied, the presence of heavy metals and other chemical waste materials form the Uadara barracks garbage deposit site were found to greatly pollute the soil and particularly the water bodies around the Armed Forces Senior High School. (au)

In-vivo counting of 241Am in human lungs and tracheobronchial lymph nodes

International Nuclear Information System (INIS)

Northcutt, A.R.; Binney, S.E.; Palmer, H.E.

1988-01-01

A study was conducted of a human male who had inhaled a mixture of 241 Am and Pu. To distinguish 241 Am deposited in the subject's lungs from translocated activity deposited in the tracheobronchial lymph nodes (TBLN), two intrinsic Ge detectors were collimated with 0.3-cm Pb sheeting. A tissue-equivalent phantom containing either 22.9 kBq (620 nCi) of 241 Am in the lungs or a 81.4 kBq (2200 nCi) 241 Am point source in the TBLN was measured. Calibration curves observed from lateral differential scans on the phantom were compared to data obtained by the same detection system for a human male with a measured lung deposition of 89 Bq (2.4 nCi) of 241 Am. Comparison of the human data to the calibration curves indicated the activity was restricted primarily to the lungs. The calibration curves demonstrate that this method is useful in determining the distribution of inhaled radioactivity between the lungs and TBLN. The measured activity from the male subject generally supported the ICRP Publication 30 model translocation prediction for class Y compounds

Application of accelerator mass spectrometry to environmental research, Trial of GC-AMS

International Nuclear Information System (INIS)

Shibata, Yasuyuki

2003-01-01

The accelerator analysis facility of the National Institute for Environmental Studies, which aims to develop a new device capable of measuring "1"4C age for each compound, is promoting the study to establish the GC-AMS that combines two-dimensional gas chromatograph (GC) and accelerator mass spectrometry (AMS). The on-line GC-AMS system for the metabolic measurement of "1"4C-labeled compounds for medicinal biochemical research is a system, in which a GC-separated sample is continuously converted into CO_2 in a combustion tube and introduced directly to a gas ion source to continuously measure "1"4C. In the "1"4C detection experiment, the concentration of CO_2 gas was changed using a helium introduction line and a sample injection valve, and CO_2 gas plus helium gas were introduced into the gas ion source. As a result, it was found that the online GC-AMS has feasibility and high potential capability. For off-line GC-AMS for environmental samples, after purification with preparative gas chromatography, the sample is converted to graphite in a vacuum line and applied to common AMS measurement. The authors collected Northwest Pacific Ocean bottom sediment cores, and performed the extraction and purification of fatty acids of specific stratigraphy and the "1"4C measurement of each compound. The age of the compound derived from the surface layer planktons was the result capable of indicating the sedimentary age of the stratigraphy. In addition, as an application study to explore the source of pollutants in the environment using "1"4C as a tracer representing the characteristics of each source, the authors started to conduct the research choosing atmospheric dust samples. As a starting point, the authors attempted to measure the "1"4C concentration of vehicle exhaust particles and incinerator fly ash particles respectively. There was hardly any "1"4C in vehicle exhaust particles. (A.O.)

Charge determination of nuclei with the AMS-02 silicon tracker

CERN Document Server

Alpat, B; Azzarello, P; Battiston, R; Bene, P; Bertucci, B; Bizzaglia, S; Bizzarri, M; Blasko, S; Bourquin, M; Bouvier, P; Burger, W J; Capell, M; Cecchi, C; Chang, Y H; Cortina, E; Dinu, N; Esposito, G; Fiandrini, E; Haas, D; Hakobyan, H; Ionica, M; Ionica, R; Kounine, A; Koutsenko, V F; Lebedev, A; Lechanoine-Leluc, C; Lin, C H; Masciocchi, F; Menichelli, M; Natale, S; Paniccia, M; Papi, A; Pauluzzi, M; Perrin, E; Pohl, M; Rapin, D; Richeux, J P; Wallraff, W; Willenbrock, M; Zuccon, P

2005-01-01

The silicon tracker of the AMS-02 detector measures the trajectory in three dimensions of electrons, protons and nuclei to high precision in a dipole magnetic field and thus measures their rigidity (momentum over charge) and the sign of their charge. In addition, it measures the specific energy loss of charged particles to determine the charge magnitude. Ladders from the AMS-02 tracker have been exposed to ion beams at CERN and GSI to study their response to nuclei from helium up to the iron group. The longest ladder, 72 multiplied by 496mm2, verified in the tests contains 12 sensors. Good charge resolution is observed up to iron.

The (e− plus e+) Spectrum from AMS

CERN Multimedia

CERN. Geneva

2015-01-01

We present a measurement of the cosmic ray e+ + e− flux in the range 0.5 GeV to 1 TeV based on the analysis of 10.6 million (e+ + e−) events. The statistics and the resolution of AMS provide a precision measurement of the flux. The flux is smooth and reveals new and distinct information.

Thermal neutron capture cross-section measurements of 243Am and 242Pu using the new mini-INCA α- and γ-spectroscopy station

International Nuclear Information System (INIS)

Marie, F.; Letourneau, A.; Fioni, G.; Deruelle, O.; Veyssiere, Ch.; Faust, H.; Mutti, P.; AlMahamid, I.; Muhammad, B.

2006-01-01

In the framework of the Mini-INCA project, dedicated to the study of Minor Actinide transmutation process in high neutron fluxes, an α- and γ-spectroscopy station has been developed and installed at the High Flux Reactor of the Laue-Langevin Institut. This set-up allows short irradiations as well as long irradiations in a high quasi-thermal neutron flux and post-irradiation spectroscopy analysis. It is well suited to measure precisely, in reference to 59 Co cross-section, neutron capture cross-sections, for all the actinides, in the thermal energy region. The first measurements using this set-up were done on 243 Am and 242 Pu isotopes. Cross-section values, at E n =0.025eV, were found to be (81.8+/-3.6)b for 243 Am and (22.5+/-1.1)b for 242 Pu. These values differ from evaluated data libraries by a factor of 9% and 17%, respectively, but are compatible with the most recent measurements, validating by the way the experimental apparatus

Neutron and gamma-ray spectra of 239PuBe and 241AmBe

International Nuclear Information System (INIS)

Vega-Carrillo, H.R.; Manzanares-Acuna, Eduardo; Becerra-Ferreiro, A.M.; Carrillo-Nunez, Aureliano

2002-01-01

Neutron and gamma-ray spectra of 239 PuBe and 241 AmBe were measured and their dosimetric features were calculated. Neutron spectra were measured using a multisphere neutron spectrometer with a 6 LiI(Eu) scintillator. The 239 PuBe neutron spectrum was measured in an open environment, while the 241 AmBe neutron spectrum was measured in a closed environment. Gamma-ray spectra were measured using a NaI(Tl) scintillator using the same experimental conditions for both sources. The effect of measuring conditions for the 241 AmBe neutron spectrum indicates the presence of epithermal and thermal neutrons. The low-resolution neutron spectra obtained with the multisphere spectrometer allows one to calculate the dosimetric features of neutron sources. At 100 cm both sources produce approximately the same count rate as that of the 4.4 MeV gamma-ray per unit of alpha emitter activity

Complexation of Am(III) by oxalate in NaClO4 media

International Nuclear Information System (INIS)

Choppin, G.R.; Chen, J.F.

1995-01-01

The complexation of Am(III) by oxalate has been investigated in solutions of NaClO 4 up to 9.0 M ionic strength at 25 degrees C. The dissociation constants of oxalic acid were determined by potentiometric titration, while the stability constants of the Am(III)-oxalate complexation were measured by the solvent extraction technique. A thermodynamic model was constructed to predict the apparent equilibrium constants at different ionic strengths by applying the Pitzer equation using parameters for the Na + -HOx - , Na + -Ox - , AmOx + -ClO 4 - , and Na + -Am(Ox) 2 - interactions obtained by fitting the data

Minimally Clinically Important Change in the Activity Measure for Post-Acute Care (AM-PAC), a Generic Patient-Reported Outcome Tool, in People With Low Back Pain.

Science.gov (United States)

Lee, Natalie; Thompson, Nicolas R; Passek, Sandra; Stilphen, Mary; Katzan, Irene L

2017-11-01

The Activity Measure for Post-Acute Care (AM-PAC) is a generic metric of patient-reported functional status. The minimal clinically important difference (MCID) in the AM-PAC score has not been determined. The study objective was to determine the MCID for AM-PAC in people with low back pain. This was a retrospective cohort study. Anchor-based and distribution-based methods were used to estimate the MCID. The Modified Low Back Pain Disability Questionnaire was used as the anchor. Adults who had a primary ICD-9 code for low back pain in at least 1 outpatient physical therapist visit during an episode of care and who completed both the AM-PAC and the Modified Low Back Pain Disability Questionnaire in at least 2 visits during the care episode were included. The MCID was calculated for the AM-PAC basic mobility version as well its adapted version, which the Cleveland Clinic uses for patients 65 years old or older. A total of 1,271 participants were eligible for study. For the AM-PAC basic mobility version, anchor-based methods yielded MCID estimates of between 3.4 and 5.1, whereas distribution-based methods yielded estimates of 1.7 to 4.2. The minimal detectable change (MDC) for the AM-PAC basic mobility version was 3.3. For the adapted AM-PAC basic mobility version, the MCID was estimated to be between 2.9 and 4.0 via anchor-based methods and between 1.2 to 3.5 via distribution-based methods. The MDC for the adapted AM-PAC basic mobility version was 3.5. The estimated MCID was designed for people with low back pain only. The MCID ranged from 3.3 to 5.1 for the AM-PAC basic mobility version and 3.5 to 4 for the adapted version, with the MDC as the lower limit. Changes in the AM-PAC for people with low back pain may be interpreted using the estimated MCID. Future studies are needed to determine the AM-PAC MCID for populations other than those with low back pain. © 2017 American Physical Therapy Association

AMS-measurements of stable platinum isotopes in presolar nanodiamonds with the help of a negative-ion-injector for VERA

International Nuclear Information System (INIS)

Melber, K.

2011-01-01

The Vienna Environmental Research Accelerator (VERA) is a universal facility for Accelerator Mass Spectrometry (AMS). VERA is based on a 3-MV tandemaccelerator and enables one to investigate isotope ratios down to 10 -16 over the whole mass range of the elements. The main application is the measurement of long-lived radioisotopes of cosmogenic or anthropogenic origin (e.g. 10 Be, 14 C, 26 Al, 36 Cl, 41 Ca, 129 I, 236 U, 244 Pu). In principle it is also possible to detect stable isotopes of trace elements (Trace Element AMS: TEAMS). TEAMS is of particular interest with regard to so-called presolar grains in meteorites. Presolar grains contain trace elements whose isotope compositions differ substantially from those of our solar system. This points to a presolar origin of these grains. Among presolar grains, nanodiamonds are still poorly understood. They are composed of only a few thousand carbon atoms and contain platinum as one of the trace elements. There are still questions on their origin. E.g. were they 'doped' with the trace elements in the environment of a supernova? Which nucleosynthetic processes have taken place? Here the isotope signatures could deliver additional information. The aim of the present work was to establish conditions at VERA for the measurement of stable platinum isotopes in presolar nanodiamonds. The difficulty of such a measurement lies in the fact that trace analyses of stable Pt isotopes are only possible if the platinum background of the ion source is low. Hence, a new negative ion injector with a new sputtersource in which platinum was never used as a test material was build up at VERA. It was then possible to carry out Pt-isotope measurements in nanodiamonds for the first time. The sample material originates from the Allende-meteorite and was purified for nanodiamonds by the cosmochemistry group of the Max Planck Institute of Chemistry in Mainz. As a main result of the measurements it was possible to detect an access of the heaviest

Application of AMS 14C measurements to criminal investigations

International Nuclear Information System (INIS)

Nakamura, T.; Ohta, T.; Nishida, M.; Ikeda, A.; Oda, H.; Kojima, S.; Niu, E.

2005-01-01

14 C variations of atmospheric CO 2 as well as carbonaceous materials of human body, such as collagen fractions from teeth and bone, tissue, hair, nail, etc., of modern humans dead or alive, are influenced by 14 C produced artificially by nuclear bomb tests in the atmosphere from late 1950s to early 1960s. By careful investigation of 14 C concentration of tree rings and human tissue samples formed in this time ranges, we can establish a relation between their 14 C concentrations and calendar year. By applying this relation to a sample whose 14 C concentration can be measured, we can estimate the formation age of the sample. In addition, sources of the drugs that were used in some criminal cases can be possibly identified by the analysis of their carbon isotope ratios ( 13 C/ 12 C and 14 C/ 12 C). This method of age determination was applied to a forensic study; i.e., to two similar cases of murder. One of the two cases is for a dead body of a modern human who was killed in 1978 and buried under the floor of the house owned by the murderer. The body was excavated in 2004 according to the confession by the murderer. 14 C abundances of several pieces of hair and one tooth (the third molar) from the body were measured with accelerator mass spectrometry (AMS), and compared with the annual change on concentrations of bomb-produced 14 C. The time of death of the body was estimated to be at around 1977, and her age was from 30 to 37 years old at that time. These estimations were consistent with the real values that were revealed after the case was solved by the confession of the real murderer who gave himself up to the police. For the other case, 14 C analysis was also consistent with the fact revealed by police investigations as well as by the confession of the real murderer.

Novel Associations between Common Breast Cancer Susceptibility Variants and Risk-Predicting Mammographic Density Measures

OpenAIRE

Stone, Jennifer; Thompson, Deborah J.; dos-Santos-Silva, Isabel; Scott, Christopher; Tamimi, Rulla M.; Lindstrom, Sara; Kraft, Peter; Hazra, Aditi; Li, Jingmei; Eriksson, Louise; Czene, Kamila; Hall, Per; Jensen, Matt; Cunningham, Julie; Olson, Janet E.

2015-01-01

Mammographic density measures adjusted for age and body mass index (BMI) are heritable predictors of breast cancer risk but few mammographic density-associated genetic variants have been identified. Using data for 10,727 women from two international consortia, we estimated associations between 77 common breast cancer susceptibility variants and absolute dense area, percent dense area and absolute non-dense area adjusted for study, age and BMI using mixed linear modeling. We found strong suppo...

Characterisation of a protection level Am-241 calibration source

Science.gov (United States)

Bass, G. A.; Rossiter, M. J.; Williams, T. T.

1992-11-01

The various measurements involved in the commissioning process of an Am-241 radioactive source and transport mechanisms to be used for protection level calibration work are detailed. The source and its handling mechanisms are described and measurements to characterize the resultant gamma ray beam are described. For the beam measurements, the inverse square law is investigated and beam uniformity is assessed. A trial calibration of ionization chambers is described. The Am-241 irradiation facility is concluded to be suitable for calibrating secondary standards as part of the calibration service offered for protection level instruments. The umbra part of beam is acceptably uniform for a range of chambers and the measurements obtained were predictable and consistent. This quality will be added to the range of qualities offered as part of the protection level secondary standard calibration service.

High-field susceptibility in ferromagnetic NpOs2

International Nuclear Information System (INIS)

Dunlap, B.D.; Aldred, A.T.; Lam, D.J.; Davidson, G.R.

1975-01-01

NpOs 2 is known to be a ferromagnet with a Curie temperature of 7.5 0 K. Previous bulk magnetization measurements indicated a field-induced magnetization even well below the transition temperature. By a measurement of the local high-field susceptibility, using the Moessbauer effect in 237 Np, a susceptibility of (1.2 +- 0.2) x 10 -2 emu/mole at 1.6 0 K is obtained, in general agreement with the bulk measurement. Such a large susceptibility is best understood by a model f itinerant magnetism, although other properties of the material indicate localized behavior

AMS of {sup 14}C at low energies

Energy Technology Data Exchange (ETDEWEB)

Suter, M.; Huber, R.; Jacob, S. [ETHZ, Zurich (Switzerland); Synal, H.A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1997-09-01

At the ETH/PSI AMS facility {sup 14}C test measurements have been performed at low terminal voltages of 0.5 and 1 MV in order to study the feasibility of AMS with very small accelerators. These experiments have demonstrated that interfering molecules ({sup 13}CH and {sup 12}CH{sub 2}) in charge states 1{sup +} and 2{sup +} can be destroyed in an adequate Ar gas stripper. These new results imply the feasibility of a new generation of very small accelerator systems for {sup 14}C. (author) 1 fig., 3 refs.

Improvement of pre-treatment method for 36Cl/Cl measurement of Cl in natural groundwater by AMS

International Nuclear Information System (INIS)

Nakata, Kotaro; Hasegawa, Takuma

2011-01-01

Estimation of 36 Cl/Cl by accelerator mass spectrometry (AMS) is a useful method to trace hydrological processes in groundwater. For accurate estimation, separation of SO 4 2- from Cl - in groundwater is required because 36 S affects AMS measurement of 36 Cl. Previous studies utilized the difference in solubility between BaSO 4 and BaCl 2 (BaSO 4 method) to chemically separate SO 4 2- from Cl - . However, the accuracy of the BaSO 4 method largely depends on operator skill, and consequently Cl - recovery is typically incomplete (70-80%). In addition, the method is time consuming (>1 week), and cannot be applied directly to dilute solutions. In this study, a method based on ion-exchange column chromatography (column method) was developed for separation of Cl - and SO 4 2- . Optimum conditions were determined for the diameter and height of column, type and amount of resin, type and concentration of eluent, and flow rate. The recovery of Cl - was almost 100%, which allowed complete separation from SO 4 2- . The separation procedure was short ( 4 methods, and then analyzed by AMS to estimate 36 S counts and 36 Cl/Cl values. 36 S counts in samples processed by the column method were stable and lower than those from the BaSO 4 method. The column method has the following advantages over the BaSO 4 method: (1) complete and stable separation of Cl - and SO 4 2- , (2) less operator influence on results, (3) short processing time ( - , and (5) concentration of Cl - and separation from SO 4 2- in the one system for dilute solutions.

A new AMS facility at Inter University Accelerator Centre, New Delhi

Science.gov (United States)

Kumar, Pankaj; Chopra, S.; Pattanaik, J. K.; Ojha, S.; Gargari, S.; Joshi, R.; Kanjilal, D.

2015-10-01

Inter University Accelerator Centre (IUAC), a national facility of government of India, is having a 15UD Pelletron accelerator for multidisciplinary ion beam based research programs. Recently, a new accelerator mass spectrometry (AMS) facility has been developed after incorporating many changes in the existing 15UD Pelletron accelerator. A clean chemistry laboratory for 10Be and 26Al with all the modern facilities has also been developed for the chemical processing of samples. 10Be measurements on sediment samples, inter laboratory comparison results and 26Al measurements on standard samples are presented in this paper. In addition to the 10Be and 26Al AMS facilities, a new 14C AMS facility based on a dedicated 500 kV tandem ion accelerator with two cesium sputter ion sources, is also being setup at IUAC.

An integrated data-analysis and database system for AMS 14C

International Nuclear Information System (INIS)

Kjeldsen, Henrik; Olsen, Jesper; Heinemeier, Jan

2010-01-01

AMSdata is the name of a combined database and data-analysis system for AMS 14 C and stable-isotope work that has been developed at Aarhus University. The system (1) contains routines for data analysis of AMS and MS data, (2) allows a flexible and accurate description of sample extraction and pretreatment, also when samples are split into several fractions, and (3) keeps track of all measured, calculated and attributed data. The structure of the database is flexible and allows an unlimited number of measurement and pretreatment procedures. The AMS 14 C data analysis routine is fairly advanced and flexible, and it can be easily optimized for different kinds of measuring processes. Technically, the system is based on a Microsoft SQL server and includes stored SQL procedures for the data analysis. Microsoft Office Access is used for the (graphical) user interface, and in addition Excel, Word and Origin are exploited for input and output of data, e.g. for plotting data during data analysis.

Creation of subsonic macro-and microjets facilities and automated measuring system (AMS-2) for the spatial - temporal hot - wire anemometric visualization of jet flow field

Science.gov (United States)

Sorokin, A. M.; Grek, G. R.; Gilev, V. M.; Zverkov, I. D.

2017-10-01

Macro-and microjets facilities for generation of the round and plane subsonic jets are designed and fabricated. Automated measuring system (AMS - 2) for the spatial - temporal hot - wire anemometric visualization of jet flow field is designed and fabricated. Coordinate device and unit of the measurement, collecting, storage and processing of hot - wire anemometric information were integrated in the AMS. Coordinate device is intended for precision movement of the hot - wire probe in jet flow field according to the computer program. At the same time accuracy of the hot - wire probe movement is 5 microns on all three coordinates (x, y, z). Unit of measurement, collecting, storage and processing of hot - wire anemometric information is intended for the hot - wire anemometric measurement of the jet flow field parameters (registration of the mean - U and fluctuation - u' characteristics of jet flow velocity), their accumulation and preservation in the computer memory, and also carries out their processing according to certain programms.

Cosmic ray and gamma astrophysics with the AMS-02 experiment

International Nuclear Information System (INIS)

Natale, Sonia

2006-01-01

The Alpha Magnetic Spectrometer (AMS) is a particle physics detector designed to operate on the International Space Station (ISS) for a minimum period of three years. The aim of AMS is the direct detection of charged particles in the rigidity range from 0.5 GV to few TV to perform high statistics studies of cosmic rays in space and a search for antimatter and dark matter. AMS will provide precise gamma measurements in the GeV range. In addition, the good angular resolution and identification capabilities of the detector will allow clean studies of galactic and extra-galactic sources, the diffuse gamma background and gamma ray bursts

Transpressional deformation style and AMS fabrics adjacent to the southernmost segment of the San Andreas fault, Durmid Hill, CA

Science.gov (United States)

French, M.; Wojtal, S. F.; Housen, B.

2006-12-01

In the Salton Trough, the trace of the San Andreas Fault (SAF) ends where it intersects the NNW-trending Brawley seismic zone at Durmid Hill (DH). The topographic relief of DH is a product of faulting and folding of Pleistocene Borrego Formation strata (Babcock, 1974). Burgmann's (1991) detailed mapping and analysis of the western part of DH showed that the folds and faults accommodate transpression. Key to Burgmann's work was the recognition that the ~2m thick Bishop Ash, a prominent marker horizon, has been elongated parallel to the hinges of folds and boudinaged. We are mapping in detail the eastern portion of DH, nearer to the trace of the SAF. Folds in the eastern part of DH are tighter and thrust faulting is more prominent, consistent with greater shortening magnitude oblique to the SAF. Boudinage of the ash layer again indicates elongation parallel to fold hinges and subparallel to the SAF. The Bishop Ash locally is limbs in eastern DH, suggesting that significant continuous deformation accompanied the development of map-scale features. We measured anisotropy of magnetic susceptibility (AMS) fabrics in the Bishop Ash in order to assess continuous deformation in the Ash at DH. Because the Bishop Ash at DH is altered, consisting mainly of silica glass and clay minerals, samples from DH have significantly lower magnetic susceptibilities than Bishop Ash samples from elsewhere in the Salton Trough. With such low susceptibilities, there is significant scatter in the orientation of magnetic foliation and lineation in our samples. Still, in some Bishop samples within 1 km of the SAF, magnetic foliation is consistent with fold-related flattening. Magnetic lineation in these samples is consistently sub-parallel to fold hinges, parallel to the elongation direction inferred from boudinage. Even close to the trace of the SAF, this correlation breaks down in map-scale zones where fold hinge lines change attitude, fold shapes change, and the distribution and orientations

In-flight operations and status of the AMS-02 silicon tracker

OpenAIRE

Ambrosi, G.; Azzarello, P.; Battiston, R.; Bertucci, B.; Choumilov, E.; Choutko, V.; Crispoltoni, M.; Delgado, C.; Duranti, M.; Donnini, F.; D'Urso, D.; Fiandrini, E.; Formato, V.; Graziani, M.; Habiby, M.

2016-01-01

The AMS-02 detector is a large acceptance magnetic spectrometer operating on the International Space Station since May 2011. More than 60 billion events have been collected by the instrument as of today. One of the key subdetectors of AMS-02 is the microstrip silicon Tracker, designed to precisely measure the trajectory and absolute charge of cosmic rays in the GeV-TeV energy range. In addition, with the magnetic field, is also measuring the particle magnetic rigidity, defined as R = pc/Ze, a...

CO2-laser decomposition method of carbonate for AMS 14C measurements

International Nuclear Information System (INIS)

Kitagawa, Hiroyuki

2013-01-01

A CO 2 laser decomposition method enabled the efficient preparation of carbonate samples for AMS 14 C measurement. Samples were loaded in a vacuum chamber and thermally decomposed using laser emission. CO 2 liberated from the carbonate was directly trapped in the cold finger trap of a small CO 2 reduction reactor and graphitized by a hydrogen gas reduction method using catalytic iron powder. The fraction modern values for 0.07–0.57 mg of carbon, obtained from 200 μm-diameter spots of IAEA-C1, varied with sample size in the range of 0.00072 ± 0.00003 to 0.00615 ± 0.00052. The contamination induced by the laser decomposition method and the following graphite handling was estimated to be 0.53 ± 0.21 μg of modern carbon, assuming a constant amount of extraneous carbon contamination. This method could also make it possible to avoid the time-consuming procedures of the conventional acid dissolution method that involves multiple complex steps for the preparation of carbonate samples.

The new AMS control centre

CERN Multimedia

Anaïs Schaeffer

2011-01-01

Construction work for the future AMS control room began in November 2010 and should be finished this June. The new building, which will have been completed in record time thanks to the professionalism of the project team, will soon be ready to receive the initial data from the AMS experiment.     Luigi Scibile and Michael Poehler, from the GS department, at the AMS control centre construction site.   The Alpha Magnetic Spectrometer (AMS) is due to wing its way towards the International Space Station (ISS) on board the shuttle Discovery in April. Mainly intended for research on antimatter and dark matter, the data collected by AMS will be sent to Houston in the United States and then directly to CERN’s new Building 946. Construction work for the AMS control centre building on the Route Gentner at CERN’s Prévessin site started in November 2010 and must be completed in time to receive the first data from the spectrometer in June. “It normall...

Linear thermal expansion, thermal diffusivity and melting temperature of Am-MOX and Np-MOX

International Nuclear Information System (INIS)

Prieur, D.; Belin, R.C.; Manara, D.; Staicu, D.; Richaud, J.-C.; Vigier, J.-F.; Scheinost, A.C.; Somers, J.; Martin, P.

2015-01-01

Highlights: • The thermal properties of Np- and Am-MOX solid solutions were investigated. • Np- and Am-MOX solid solutions exhibit the same linear thermal expansion. • The thermal conductivity of Am-MOX is about 10% higher than that of Np-MOX. • The melting temperatures of Np-MOX and Am-MOX are 3020 ± 30 K and 3005 ± 30 K, respectively. - Abstract: The thermal properties of Np- and Am-MOX solid solution materials were investigated. Their linear thermal expansion, determined using high temperature X-ray diffraction from room temperature to 1973 K showed no significant difference between the Np and the Am doped MOX. The thermal conductivity of the Am-MOX is about 10% higher than that of Np-MOX. The melting temperatures of Np-MOX and Am-MOX, measured using a laser heating self crucible arrangement were 3020 ± 30 K and 3005 ± 30 K, respectively

Cosmic rays measurements between 1 GeV and 1 PeV by AMS and CREAM experiments; Mesures des rayons cosmiques entre le GeV et le PeV par les experiences AMS et CREAM

Energy Technology Data Exchange (ETDEWEB)

Mangin-Brinet, M

2007-11-15

The AMS (Alpha Magnetic Spectrometer) and CREAM (Cosmic Ray Energetics and Mass) experiments that are devoted to the detection of cosmic radiations have a similar architecture and both use a Cherenkov detector whose scintillating material is a silicon aerogel. The performance of the Cherenkov detector rests on an accurate knowledge of the refractive index of the aerogel plane. This report deals with an adequate methodology of measuring the refractive index. The first chapter reviews the contributions of AMS and CREAM experiments to the physics of cosmic radiations. The second chapter presents different methods used for mapping the refractive index of the aerogel plane. The prism method is based on the measurement of the deflection of a laser beam through the sides of an aerogel tile. The most satisfying method to measure the changes in the refractive index is to use an electron beam, in this case any change infers a change in the emission angle of the Cherenkov photons that can be detected and the value of the refractive index is deduced. A new method based on the deflection of a laser beam on the 2 parallel sides of an aerogel tile has been developed. The characterization of the 2 Cherenkov detectors are given in the second and the third chapter. The last chapter presents some aspects of the simulation works and of the data processing. (A.C.)

Identification of highly susceptible individuals in complex networks

Science.gov (United States)

Tang, Shaoting; Teng, Xian; Pei, Sen; Yan, Shu; Zheng, Zhiming

2015-08-01

Identifying highly susceptible individuals in spreading processes is of great significance in controlling outbreaks. In this paper, we explore the susceptibility of people in susceptible-infectious-recovered (SIR) and rumor spreading dynamics. We first study the impact of community structure on people's susceptibility. Although the community structure can reduce the number of infected people for same infection rate, it will not significantly affect nodes' susceptibility. We find the susceptibility of individuals is sensitive to the choice of spreading dynamics. For SIR spreading, since the susceptibility is highly correlated to nodes' influence, the topological indicator k-shell can better identify highly susceptible individuals, outperforming degree, betweenness centrality and PageRank. In contrast, in rumor spreading model, where nodes' susceptibility and influence have no clear correlation, degree performs the best among considered topological measures. Our finding highlights the significance of both topological features and spreading mechanisms in identifying highly susceptible population.

Accelerator mass spectrometry (AMS) dating from the modern age to the past million age

International Nuclear Information System (INIS)

Sasa, K.; Nagashima, Y.; Seki, R.; Takahashi, T.; Tosaki, Y.; Sueki, K.; Bessyo, K.; Matsumura, H.; Miura, T.

2006-01-01

A multi-nuclide Accelerator Mass Spectrometry system at the University of Tsukuba (Tsukuba AMS system) is able to measure the long-lived radioisotopes of 14 C, 26 Al, 36 Cl and 129 I. The Tsukuba AMS system is able to perform AMS measurements with the terminal voltage of more than 10 MV. It is difficult to estimate the modern age dating (timescale of the past ten years) by the AMS dating method because the low attenuation of long-lived radioisotopes. The atomic bomb-produced radioisotopes are proposed as the environmental traces for the modern age dating. There is the advantage that the long half life of radioisotopes makes the attenuation negligilbe compared with the short half life of radioisotopes. We applied the 36 Cl bomb pulse as a dating tool for modern groundwater (∼50 years) instead of the 3 H bomb pulse. In addition, we have developed 32 Si-AMS system. The half life of 32 Si is about 140 years, therefore 32 Si-AMS is a useful tool for the modern age dating. On the other hand, we have started a new project to measure the cosmogenic nuclide of 36 Cl in an ice core retrieved from Dome Fuji station at Antarctic in order to investigate the past solar activity and the past earth environment as the timescale of the past million age. (author)

Beneficial uses of 241Am

International Nuclear Information System (INIS)

Mangeng, C.A.; Thayer, G.R.

1984-05-01

This report assesses the uses of 241 Am and the associated costs and supply. The study shows that 241 Am-fueled radioisotope thermoelectric generators in the range of 1 to 5 W electrical provide the most promising use of kilogram amounts of this isotope. For medical uses, where purity is essential, irradiation of 241 Am can produce 97% pure 238 Pu at $21,000/g. Using a pyro-metallurgical process, 241 Am could be recovered from molten salt extraction (MSE) residues at an estimated incremental cost of $83/g adjusted to reflect the disposal costs of waste products. This cost of recovery is less than the $300/g cost for disposal of the 241 Am contained in the MSE residues

Strain Distribution in a Partially Molten Crust: Insights from the AMS Study of Carlos Chagas Anatexite, ARAÇUAI Belt (se Brazil)

Science.gov (United States)

Cavalcante, G.; Silva, M.; Vauchez, A. R.

2012-12-01

Anatectic domains, characterized by abundant migmatites, represent portions of the middle crust that have been partially molten. The Carlos Chagas anatexite is a unit that includes diatexites, metaxites and anatetic, peraluminous granites. It is localized in eastern domain of the Araçuaí Belt, which was formed during the amalgamation of West Gondwana by the collision of the Sao Francisco and Congo cratons. This orogenic segment underwent a synkinematic high temperature (>750oC)-low pressure (~ 6MPa) metamorphism that causes widespread partial melting of the middle crust. The Carlos Chagas unit is composed by quartz, feldspar, garnet, biotite, sillimanite, ilmenite, rutile and cordierite. U-Pb data indicates that its crystallization occurred c. a. 574 ~ 3 Ma. The main feature of this migmatite is the presence of a pervasive magmatic foliation, which is marked by the preferential alignment of biotite, alkali feldspars and plagioclase. At the grain scale, quartz displays evidence of interstitial crystallization and few solid-state deformation fabrics are observed. We used anisotropy of magnetic susceptibility (AMS) as a tool for recovering mineral fabric and thus the flow field of the Carlos Chagas anatexite. Magnetic properties of 153 samples were measured. They yield dominantly low values of the bulk magnetic susceptibility (km 0) being dominantly more frequent than prolates ones. These magnetics characteristics are consistent with biotite being the dominant carrier of the AMS. Magnetic foliations and lineations suggest two main structural patterns. The northern portion of the studied area shows shallowly plunging lineations (02° - 20°) to SE (140°-120°) or NW (340°-300°), while the foliation strikes NW-SE with shallow dips (03°-10°). Local subvertical foliation dips (70°) are due to NE-SW trending transcurrent shear zones. The southern region shows complex magnetic fabric patterns. Magnetic lineation plunges range from 05° to 58°, in varied directions

AMS Radiocarbon Dating at Notre Dame

Science.gov (United States)

Howard, Sean

2014-09-01

Current development of a local radiocarbon dating method using Accelerator Mass Spectrometry (AMS) at the University of Notre Dame seeks to provide sensitive, reproducible, and accurate measurements for future interdisciplinary projects. While AMS has been the premier radiocarbon dating method for a few decades, repurposing Notre Dame's FN Tandem accelerator for radiocarbon dating has provided many unique challenges. Experiments have shown radiocarbon dating possible and reproducible using the FN Tandem accelerator, found optimal settings for said accelerator, and established sensitivity limits comparable to dedicated radiocarbon dating facilities. In addition, there is ongoing work to create a local chemistry lab to convert organic artifacts into graphite samples to be dated locally. Once the chemistry side has been completed, several artifacts from the IAEA's radiocarbon intercomparison have been procured. Dating these previously studied artifacts will provide an additional measure on the accuracy and repeatability of both the accelerator and chemical treatment. Provided that these IAEA artifacts are dated successfully, exciting projects will ensue, such as the authentication of artwork and dating of anthropological samples.

Radiochemical determination of the neutron capture cross sections of {sup 241}Am irradiated in the JMTR reactor

Energy Technology Data Exchange (ETDEWEB)

Shinohara, N.; Hatsukawa, Y.; Hata, K.; Kohno, N. [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

1997-03-01

The thermal neutron capture cross section {sigma}{sub 0} and Resonance integral I{sub 0} of {sup 241}Am leading to the production of {sup 242m}Am and {sup 242g}Am were measured by radiochemical method. The cross sections obtained in this study are {sigma}{sub 0}=60.9 {+-} 2.6 barn, I{sub 0}=213 {+-} 13 barn for {sup 241}Am(n,{gamma}){sup 242m}Am and {sigma}{sub 0}=736 {+-} 31 barn, I{sub 0}=1684 {+-} 92 barn for {sup 241}Am(n,{gamma}){sup 242g}Am. (author)

Nickel remediation by AM-colonized sunflower.

Science.gov (United States)

Ker, Keomany; Charest, Christiane

2010-08-01

This greenhouse study aimed to examine the contribution of arbuscular mycorrhizal (AM) colonization on the uptake of and tolerance to nickel (Ni) in sunflower (Helianthus annuus L.). We hypothesized that AM colonization increases Ni content and tolerance in sunflower grown under varying soil Ni concentrations. The combined effect of AM colonization and soil Ni input on the assimilation of nitrogen, in particular the activity of glutamine synthetase (GS), in sunflower plants was also investigated. A factorial experimental design was performed with sunflower cv. Lemon Queen, with or without the AM fungus, Glomus intraradices Schenck & Smith, and treated with 0, 100, 200, or 400 mg Ni kg(-1) dry soil (DS). The AM colonization significantly enhanced plant growth and Ni content, especially at the lower soil Ni treatments. Furthermore, the AM plants exposed to the highest soil Ni level of 400 mg Ni kg(-1) DS had a significantly higher shoot Ni extracted percentage than non-AM plants, suggesting that the AM symbiosis contributed to Ni uptake, then its translocation from roots to shoots. The AM colonization also significantly increased the GS activity in roots, this being likely an indicator of an enhanced Ni tolerance. These findings support the hypothesis that AM symbiosis contributes to an enhanced Ni plant uptake and tolerance and should be considered as part of phytoremediation strategies.

A new AMS facility at Inter University Accelerator Centre, New Delhi

Energy Technology Data Exchange (ETDEWEB)

Kumar, Pankaj, E-mail: pkb@iuac.res.in [Inter-University Accelerator Center (IUAC), New Delhi (India); Chopra, S. [Inter-University Accelerator Center (IUAC), New Delhi (India); Pattanaik, J.K. [Department of Earth Sciences, Indian Institute of Science Education and Research Kolkata, Nadia, WB (India); Ojha, S.; Gargari, S.; Joshi, R.; Kanjilal, D. [Inter-University Accelerator Center (IUAC), New Delhi (India)

2015-10-15

Inter University Accelerator Centre (IUAC), a national facility of government of India, is having a 15UD Pelletron accelerator for multidisciplinary ion beam based research programs. Recently, a new accelerator mass spectrometry (AMS) facility has been developed after incorporating many changes in the existing 15UD Pelletron accelerator. A clean chemistry laboratory for {sup 10}Be and {sup 26}Al with all the modern facilities has also been developed for the chemical processing of samples. {sup 10}Be measurements on sediment samples, inter laboratory comparison results and {sup 26}Al measurements on standard samples are presented in this paper. In addition to the {sup 10}Be and {sup 26}Al AMS facilities, a new {sup 14}C AMS facility based on a dedicated 500 kV tandem ion accelerator with two cesium sputter ion sources, is also being setup at IUAC.

Methods of assessment of whole body 241Am content

International Nuclear Information System (INIS)

Foltanova, S.; Malatova, I.; Klisak, J.

1998-01-01

This paper discuss an influence of different skull phantoms on efficiency of the measurement. Description of some methods of an assessment of the 241 Am content in the human skeleton from measurements performed over long bones of the human body is also offered. (authors)

Preparation of a multi-isotope plutonium AMS standard and preliminary results of a first inter-lab comparison

Energy Technology Data Exchange (ETDEWEB)

Dittmann, B.-A.; Dunai, T.J. [Institute of Geology and Mineralogy, University of Cologne, Greinstr. 4-6, 50939 Cologne (Germany); Dewald, A.; Heinze, S.; Feuerstein, C. [Institute of Nuclear Physics, University of Cologne, Zülpicher Str. 77, 50937 Cologne (Germany); Strub, E. [Division of Nuclear Chemistry, University of Cologne, Zülpicher Str. 45, 50674 Cologne (Germany); Fifield, L.K.; Froehlich, M.B.; Tims, S.G.; Wallner, A. [Department of Nuclear Physics, Research School of Physics & Engineering, Australian National University, Canberra ACT 2601 (Australia); Christl, M. [Laboratory of Ion Beam Physics, ETH Zurich, Otto-Stern-Weg 5, 8093 Zurich (Switzerland)

2015-10-15

The motivation of this work is to establish a new multi-isotope plutonium standard for isotopic ratio measurements with accelerator mass spectrometry (AMS), since stocks of existing solutions are declining. To this end, certified reference materials (CRMs) of each of the individual isotopes {sup 239}Pu, {sup 240}Pu, {sup 242}Pu and {sup 244}Pu were obtained from JRC IRMM (Joint Research Center Institute for Reference Materials and Measurements). These certified reference materials (IRMM-081a, IRMM-083, IRMM-043 and IRMM-042a) were diluted with nitric acid and mixed to obtain a stock standard solution with an isotopic ratio of approximately 1.0:1.0:1.0:0.1 ({sup 239}Pu:{sup 240}Pu:{sup 242}Pu:{sup 244}Pu). From this stock solution, samples were prepared for measurement of the plutonium isotopic composition by AMS. These samples have been measured in a round-robin exercise between the AMS facilities at CologneAMS, at the ANU Canberra and ETH Zurich to verify the isotopic ratio and to demonstrate the reproducibility of the measurements. The results show good agreement both between the different AMS measurements and with the gravimetrically determined nominal ratios.

[Antimicrobial susceptibility in Chile 2012].

Science.gov (United States)

Cifuentes-D, Marcela; Silva, Francisco; García, Patricia; Bello, Helia; Briceño, Isabel; Calvo-A, Mario; Labarca, Jaime

2014-04-01

Bacteria antimicrobial resistance is an uncontrolled public health problem that progressively increases its magnitude and complexity. The Grupo Colaborativo de Resistencia, formed by a join of experts that represent 39 Chilean health institutions has been concerned with bacteria antimicrobial susceptibility in our country since 2008. In this document we present in vitro bacterial susceptibility accumulated during year 2012 belonging to 28 national health institutions that represent about 36% of hospital discharges in Chile. We consider of major importance to report periodically bacteria susceptibility so to keep the medical community updated to achieve target the empirical antimicrobial therapies and the control measures and prevention of the dissemination of multiresistant strains.

Effects of refrigerating preinoculated Vitek cards on microbial physiology and antibiotic susceptibility

Science.gov (United States)

Skweres, Joyce A.; Bassinger, Virginia J.; Mishra, S. K.; Pierson, Duane L.

1992-01-01

Reference cultures of 16 microorganisms obtained from the American Type Culture Collection and four clinical isolates were used in standardized solutions to inoculate 60 cards for each test strain. A set of three ID and three susceptibility cards was processed in the Vitek AutoMicrobic System (AMS) immediately after inoculation. The remaining cards were refrigerated at 4 C, and sets of six cards were removed and processed periodically for up to 17 days. The preinoculated AMS cards were evaluated for microorganism identification, percent probability of correct identification, length of time required for final result, individual substrate reactions, and antibiotic minimal inhibitory/concentration (MIC) values. Results indicate that 11 of the 20 microbes tested withstood refrigerated storage up to 17 days without detectable changes in delineating characteristics. MIC results appear variable, but certain antibiotics proved to be more stable than others. The results of these exploratory studies will be used to plan a microgravity experiment designed to study the effect of microgravity on microbial physiology and antibiotic sensitivity.

Low-dose DNA adduct dosimetry by accelerator mass spectrometry (AMS)

International Nuclear Information System (INIS)

Turteltaub, K.W.; Felton, J.S.; Vogel, J.S.; Gledhill, B.L.; Davis, J.C.; Snyderwine, E.G.; Thorgeirsson, S.S.; Adamson, R.H.

1991-01-01

DNA adduction was measured following exposure to low doses of [2- 14 C]-2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) [2- 14 C]-2-amino-3-methylimidazo[4,5-f]quinoline (IQ) and [U- 14 C]-2,3,7,8-tetrachlorodibenzo-p-dioxin by AMS, a technique used in the earth sciences but not previously in toxicological research. The ability to measure low concentrations of rare isotopes suggested that biomedical research was a potentially powerful application for this technology. Sensitivity of the method was found to be one adduct per 10 11 nucleotides. No DNA adduct formation could be detected in TCDD treated rodents. DNA adducts in cynomolgus monkey lymphocytes following exposure to 500 μg/kg IQ peaked between 6 and 18 hrs following exposure. Sensitivity was limited mainly by the abundance of 14 C in contemporary carbon. Hosts depleted in radiocarbon are being developed, potentially increasing sensitivity another 3 orders of magnitude. These results demonstrate the high sensitivity of AMS for tracing molecules following administration of low levels of isotopically-labeled xenobiotics. In addition to 14 C measurement, AMS offers potential to conduct studies with other isotopes, particularly 3 H and 41 Ca

Adolescent Susceptibility to Peer Influence in Sexual Situations.

Science.gov (United States)

Widman, Laura; Choukas-Bradley, Sophia; Helms, Sarah W; Prinstein, Mitchell J

2016-03-01

One consistent predictor of adolescents' engagement in sexual risk behavior is their belief that peers are engaging in similar behavior; however, not all youth are equally susceptible to these peer influence effects. Understanding individual differences in susceptibility to peer influence is critical to identifying adolescents at risk for negative health outcomes. The purpose of this project was to identify predictors of susceptibility to peer influence using a novel performance-based measure of sexual risk taking. Participants were 300 early adolescents (Mage = 12.6 years; 53% female; 44% Caucasian) who completed (1) a pretest assessment of demographics, sexual attitudes, and hypothetical scenarios measuring the likelihood of engaging in sexual risk behavior and (2) a subsequent experimental procedure that simulated an Internet chat room in which youth believed that they were communicating with peers regarding these same hypothetical scenarios. In reality, these "peers" were computer-programmed e-confederates. Changes in responses to the sexual scenarios in the private pretest versus during the public chat room provided a performance-based measure of peer influence susceptibility. In total, 78% of youth provided more risky responses in the chat room than those in pretest. The most robust predictor of this change was gender, with boys significantly more susceptible to peer influence than girls. Significant interactions also were noted, with greater susceptibility among boys with later pubertal development and African-American boys. Results confirm that not all youth are equally susceptible to peer influence. Consistent with sexual script theory, boys evidence greater susceptibility to social pressure regarding sexual behavior than girls. Copyright © 2016 Society for Adolescent Health and Medicine. Published by Elsevier Inc. All rights reserved.

Alpha and conversion electron spectroscopy of 238,239Pu and 241Am and alpha-conversion electron coincidence measurements

Energy Technology Data Exchange (ETDEWEB)

Dion, Michael P.; Miller, Brian W.; Warren, Glen A.

2016-09-01

A technique to determine the isotopics of a mixed actinide sample has been proposed by measuring the coincidence of the alpha particle during radioactive decay with the conversion electron (or Auger) emitted during the relaxation of the daughter isotope. This presents a unique signature to allow the deconvolution of isotopes that possess overlapping alpha particle energy. The work presented here are results of conversion electron spectroscopy of 241Am, 238Pu and 239Pu using a dual-stage peltier-cooled 25 mm2 silicon drift detector. A passivated ion implanted planar silicon detector provided measurements of alpha spectroscopy. The conversion electron spectra were evaluated from 20–55 keV based on fits to the dominant conversion electron emissions, which allowed the relative conversion electron emission intensities to be determined. These measurements provide crucial singles spectral information to aid in the coincident measurement approach.

Measurement of the removal sechtion of biological protection concretes in the spectrum of an AmBe source

International Nuclear Information System (INIS)

Sandin, C.; Tenrreiro, J.; Desdin, L.; Sarria, P.; Monne, G.; Tellez, E.; Csikai, J

1992-01-01

A method to measure the neutron removal cross sections in cuban concrete for biological protection using the average spectrum of a radioisotopic source was developed. The method was verified by the measurements of different materials with know removal cross sections like Pb, paraffin and water. These spetial cuban concrete are elaborated on the basis of arids of limestone, limonite, magnetite, baryte and serpentine. The aim of this work is to contribute to the characterization of those concretes for its use in cuban nuclear installations. In the experiments were used an AmBe source with an strength of 10 6 n/s. and a long counter detector with associated electronics. It can be seen in the table that the concretes of magnetite and limonite have the best shielding properties for neutrons

Twelve years of follow up of cases with old 241Am internal contamination.

Science.gov (United States)

Malátová, Irena; Vrba, Tomás; Becková, Vera; Pospísilová, Helena

2010-10-01

A group of workers internally contaminated with Am have been followed for about 12 years. The source of contamination was AmO2 powder used for production of AmBe neutron sources and other applications. The production of some radionuclide sources included chemical treatment of the original material, which transformed the americium into the nitrate, but mostly powder metallurgy was used for production of sources for smoke detectors. In vivo measurement of the workers was performed with two LEGe detectors placed near the head of the measured person. Calibration was performed with four different physical skull phantoms of different origin and a voxel phantom with Monte Carlo simulation, which was developed to fit the head sizes of individual persons. Samples of urine and feces were analyzed by means of radiochemical separation followed by alpha-spectrometry. Separation of 241Am from mineralized excreta was performed by combined anion exchange and extraction chromatographic techniques. As a tracer, 243Am was used. When the measured data (83 data on skeletal activity, activity in 389 bioassay samples) were compared with International Commission on Radiological Protection's and Leggett's biokinetic models of americium, it was found that in most cases, after more than 15 y since the intake, the excretion rate was lower (or skeletal activity higher) than predicted. On the other hand, the ratio of excreted activity in urine and feces agrees well with model predictions.

Disturbance from Am-241 Photons of the Cellular Dose by Am-241 Alpha Emissions: Am-241 as an alternative source of alpha particles to radon daughters

International Nuclear Information System (INIS)

Lee, Ki-Man; Kim, Eun-Hee

2015-01-01

The Radiation Bioengineering Laboratory (RadBio Lab) at Seoul National University (SNU) has built an Am-241 alpha particle irradiator for study of cellular responses to radiation from radon daughters. The radon daughters of concern that cause internal exposure from inhalation of radon-contaminated air are Po-218, Po-214 and Po-210. In their alpha decay schemes, the yields of photon emissions are negligible. Unfortunately, Am-241, the source of alpha irradiator in RadBio Lab, emits photons at every alpha decay while transforming to Np-237 of long half-life. Employing Am-241 as the source simulating radon daughters, therefore, requires that photon emissions from Am-241 be specified in term of dose contribution. In this study, Monte Carlo calculations have been made to characterize dose contributions of Am-241 photon emissions. This study confirms that disturbance from Am-241 photon emissions of the cellular dose by Am-241 alpha emissions is negligible. Dose contamination fraction from photon emissions was 8.02 .. 10 -6 at 25 mm SSD at maximum. Also, note that LET in tissue-equivalent medium varies within about 20% for alpha particles at energies over 5 MeV

An integrated data-analysis and database system for AMS {sup 14}C

Energy Technology Data Exchange (ETDEWEB)

Kjeldsen, Henrik, E-mail: kjeldsen@phys.au.d [AMS 14C Dating Centre, Department of Physics and Astronomy, Aarhus University, Aarhus (Denmark); Olsen, Jesper [Department of Earth Sciences, Aarhus University, Aarhus (Denmark); Heinemeier, Jan [AMS 14C Dating Centre, Department of Physics and Astronomy, Aarhus University, Aarhus (Denmark)

2010-04-15

AMSdata is the name of a combined database and data-analysis system for AMS {sup 14}C and stable-isotope work that has been developed at Aarhus University. The system (1) contains routines for data analysis of AMS and MS data, (2) allows a flexible and accurate description of sample extraction and pretreatment, also when samples are split into several fractions, and (3) keeps track of all measured, calculated and attributed data. The structure of the database is flexible and allows an unlimited number of measurement and pretreatment procedures. The AMS {sup 14}C data analysis routine is fairly advanced and flexible, and it can be easily optimized for different kinds of measuring processes. Technically, the system is based on a Microsoft SQL server and includes stored SQL procedures for the data analysis. Microsoft Office Access is used for the (graphical) user interface, and in addition Excel, Word and Origin are exploited for input and output of data, e.g. for plotting data during data analysis.

Design of a graphite-moderated {sup 241}Am-Li neutron field to simulate reactor spectra

Energy Technology Data Exchange (ETDEWEB)

Tsujimura, N., E-mail: tsujimura.norio@jaea.go.j [Nuclear Fuel Cycle Engineering Laboratories, Japan Atomic Energy Agency, 4-33, Tokai-mura, Ibaraki-ken, 319-1194 (Japan); Yoshida, T. [Nuclear Fuel Cycle Engineering Laboratories, Japan Atomic Energy Agency, 4-33, Tokai-mura, Ibaraki-ken, 319-1194 (Japan)

2010-12-15

A neutron calibration field using {sup 241}Am-Li sources and a moderator was designed to simulate the neutron fields found outside a reactor. The moderating assembly selected for the design calculation consists of a cube of graphite blocks with dimensions of 50 cm by 50 cm by 50 cm, in which the {sup 241}Am-Li sources are placed. Monte Carlo calculations revealed the optimal depth of the source to be 15 cm. This moderated neutron source can be used to provide a test field that has a large number of intermediate energy neutrons with a small portion of MeV component.

Basis for developing samarium AMS for fuel cycle analysis

International Nuclear Information System (INIS)

Buchholz, Bruce A.; Biegalski, Steven R.; Whitney, Scott M.; Tumey, Scott J.; Jordan Weaver, C.

2010-01-01

Modeling of nuclear reactor fuel burnup indicates that the production of samarium isotopes can vary significantly with reactor type and fuel cycle. The isotopic concentrations of 146 Sm, 149 Sm, and 151 Sm are potential signatures of fuel reprocessing, if analytical techniques can overcome the inherent challenges of lanthanide chemistry, isobaric interferences, and mass/charge interferences. We review the current limitations in measurement of the target samarium isotopes and describe potential approaches for developing Sm-AMS. AMS sample form and preparation chemistry will be discussed as well as possible spectrometer operating conditions.

AMS in drug development at GSK

International Nuclear Information System (INIS)

Young, G.C.; Ellis, W.J.

2007-01-01

A history of the use of AMS in GSK studies spanning the last 8 years (1998-2005) is presented, including use in pilot studies through to clinical, animal and in vitro studies. A brief summary of the status of GSK's in-house AMS capability is outlined and views on the future of AMS in GSK are presented, including potential impact on drug development and potential advances in AMS technology

Magnetic susceptibility characterisation of superparamagnetic microspheres

Science.gov (United States)

Grob, David Tim; Wise, Naomi; Oduwole, Olayinka; Sheard, Steve

2018-04-01

The separation of magnetic materials in microsystems using magnetophoresis has increased in popularity. The wide variety and availability of magnetic beads has fuelled this drive. It is important to know the magnetic characteristics of the microspheres in order to accurately use them in separation processes integrated on a lab-on-a-chip device. To investigate the magnetic susceptibility of magnetic microspheres, the magnetic responsiveness of three types of Dynabeads microspheres were tested using two different approaches. The magnetophoretic mobility of individual microspheres is studied using a particle tracking system and the magnetization of each type of Dynabeads microsphere is measured using SQUID relaxometry. The magnetic beads' susceptibility is obtained at four different applied magnetic fields in the range of 38-70 mT for both the mobility and SQUID measurements. The susceptibility values in both approaches show a consistent magnetic field dependence.

Physics of charged cosmic rays with the AMS experiment

Energy Technology Data Exchange (ETDEWEB)

Vialle, J.P

2000-04-01

The AMS experiment aims at searching for primordial antimatter, non-baryonic dark matter, and measuring with high statistics and high accuracy the electrically charged cosmic ray particles and light nuclei in the extraterrestrial space beyond the atmosphere. AMS is the first magnetic spectrometer which will be flown in space. It will be installed for 3 years on the international space station (ISS) in 2003. A test flight with the space shuttle DISCOVERY took place in June 1998 with a first detector and gave many results: best limit on the existence of antinuclei, fluxes of protons, leptons, and helium nuclei above the geomagnetic threshold, existence of a secondary flux below the geomagnetic threshold. These results are described below. The physics goal and perspectives for AMS on the space station with an improved detector are described as well. (author)

Integral test for Np237 and Am241 cross sections in JENDL, ENDF and JEF libraries

International Nuclear Information System (INIS)

Iwasaki, Tomohiko; Unesaki, Hironobu; Kitada, Takanori

2002-01-01

Experiments using Kyoto University critical assembly (KUCA) were performed for measuring the capture and fission reaction rates of 237 Np and 241 Am. A back-to-back fission chamber was employed for the measurement of the fission rate of 237 Np and 241 Am relative to 235 U. The capture rate of 237 Np relative to 197 Au was measured by using activation method. Eleven cores, of which the spectra were changed systematically, were mocked up for the present measurements. Five cores among the eleven were utilized for the fission reaction rate measurement. The experiment was analyzed using the Monte Carlo code MVP, the transport code TWOTRAN and the diffusion code CITATION using the libraries based on JENDL3.2, ENDF/B-VI and JEF2.2. As the results, for 237 Np, JENDL3.2 showed good agreement for both capture and fission. However, for the fission rate of 241 Am, JENDL3.2 underestimates 15-20%. On the other hand, ENDF/B-VI and JEF2.2 show different C/Es for 237 Np and 241 Am. (author)

Study of the electrochemical oxidation of Am with lacunary heteropolyanions and silver nitrate

International Nuclear Information System (INIS)

Chartier, D.

1999-01-01

Electrochemical oxidation of Am(III) with certain lacunary heteropolyanions (LHPA α 2 -P 2 W 17 O 61 10- or αSiW 11 O 39 8- ) and silver nitrate is an efficient way to prepare Am(VI). This document presents bibliographic data and an experimental study of the process. Thus, it has been established that Am(IV) is an intermediate species in the reaction and occurs in 1:1 (Amt IV LHPA) or 1:2 (Am IV (LHAP) 2 ) complexes with the relevant LHPA. These 1:1 complexes of Am(IV) have been identified and isolated in this work whereas 1:2 complexes were known from previous studies. The reactivity of these complexes in oxidation shows that 1:1 complexes of Am(IV) are oxidised much more quickly than 1:2 complexes. Apparent stability constants of Am(III) and Am(IV) complexes with the relevant LHPA have been measured for a 1 M nitric acid medium. Thermodynamic data of the reaction are then assessed: redox potentials of Am pairs are computed for a 1 M nitric acid medium containing various amount of LHPA ligands. Those results show that the role of LHPA is to stabilize the intermediate species Am(IV) by lowering the Am(IV)/Am(III) pair potential of about 1 Volt. Nevertheless, if this stabilisation is too strong (i.e. of tungsto-silicate), the oxidation of Am(IV) requires high anodic potential (more than 2 V/ENH). Then, the faradic yield of the oxidation of americium is poor because of water oxidation. This study has also shown that the main role of silver is to catalyze the electrochemical oxidation of Am IV (LHPA) X complexes. Indeed, these oxidations without silver are extremely slow. An oxygen tracer experiment has been performed during the oxidation of Am(III) in Am(VI). It has been shown that the oxygen atoms of Am(VI) (AMO 2 2+ ) come from water molecules of the solvent and not from the complexing oxygen atoms of the ligands. (author)

Estimation of cross talk between lungs and liver for 241Am using phoswich detector

International Nuclear Information System (INIS)

Mishra, Lokpati; Nadar, Minal Y.; Singh, I.S.; Sawant, P.D.

2018-01-01

241 Am is used as a tracer for in-vivo assessment of plutonium (Pu) in the lungs. Internal contamination of 241 Am is estimated by measuring its 59.5 keV photons then activity of Pu is estimated by applying Pu/ 241 Am ratio obtained from radiochemical analysis of fecal/workplace sample. According to ICRP systemic bio-kinetic model, for Type M compounds of 241 Am after 100 days post inhalation intake, 241 Am activity in liver exceeds 241 Am activity present in the lungs and goes on increasing even up to about ten years. In this work, cross talk (CT) between lungs and liver viz. CT (liver to lungs) and CT (lungs to liver) for the actinide monitoring system for 241 Am using realistic thorax Lawrence Livermore National Laboratory (LLNL) phantom were estimated. Also CT has been estimated using voxel phantom by carrying out Monte Carlo simulations in FLUKA code. This study will help in reporting the actual activity present in the individual organ (lungs, liver)

Development of a method to measure the concentration of 14C in the stack air of nuclear power plants by accelerator mass spectrometry (AMS)

International Nuclear Information System (INIS)

Stenstroem, K.; Erlandsson, B.; Hellborg, R.; Haakansson, K.; Wiebert, A.; Skog, G.

1993-04-01

C-14, a pure low-energetic beta-emitter, is produced through various nuclear reactions in nuclear power plants. Some of this C-14 is air-borne and is transported via the ventilation system through the stack of the power station and is integrated in living matter in the surroundings of the plant. The long half-life of the isotope (T1/2=5730 years) and the biological importance of carbon may lead to a not negligible contribution of the radiation dose for those living in the neighbourhood of nuclear power plants. C-14 has earlier been measured radiometrically with mainly two different methods, using proportional counters or liquid scintillators. In this report a new method is described, using an accelerator based technique. accelerator mass spectrometry (AMS). This technique has at least three advantages over the radiometrical methods. It requires only a few litres of gas per sample, which is 100-1000 times less compared to the radiometrical methods. It is insensitive to the beta and gamma rays from other radioactive isotopes in the stack air. The measuring time with AMS, about 20 minutes per sample, is considerably shorter compared to the radiometrical methods, which demand several hours per sample. The integrity of the AMS method is high and it might be convenient for regulatory supervision. (22 refs.)

The D-D Neutron Generator as an Alternative to Am(Li) Isotopic Neutron Source in the Active Well Coincidence Counter

Energy Technology Data Exchange (ETDEWEB)

McElroy, Robert Dennis [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cleveland, Steven L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-03-01

The ²³⁵U mass assay of bulk uranium items, such as oxide canisters, fuel pellets, and fuel assemblies, is not achievable by traditional gamma-ray assay techniques due to the limited penetration of the item by the characteristic ²³⁵U gamma rays. Instead, fast neutron interrogation methods such as active neutron coincidence counting must be used. For international safeguards applications, the most commonly used active neutron systems, the Active Well Coincidence Counter (AWCC), Uranium Neutron Collar (UNCL) and ²⁵²Cf Shuffler, rely on fast neutron interrogation using an isotopic neutron source [i.e., ²⁵²Cf or Am(Li)] to achieve better measurement accuracies than are possible using gamma-ray techniques for high-mass, high-density items. However, the Am(Li) sources required for the AWCC and UNCL systems are no longer manufactured, and newly produced systems rely on limited supplies of sources salvaged from disused instruments. The ²⁵²Cf shuffler systems rely on the use of high-output ²⁵²Cf sources, which while still available have become extremely costly for use in routine operations and require replacement every five to seven years. Lack of a suitable alternative neutron interrogation source would leave a potentially significant gap in the safeguarding of uranium processing facilities. In this work, we made use of Oak Ridge National Laboratory’s (ORNL’s) Large Volume Active Well Coincidence Counter (LV-AWCC) and a commercially available deuterium-deuterium (D-D) neutron generator to examine the potential of the D-D neutron generator as an alternative to the isotopic sources. We present the performance of the LV-AWCC with D-D generator for the assay of ²³⁵U based on the results of Monte Carlo N-Particle (MCNP) simulations and measurements of depleted uranium (DU), low enriched uranium (LEU), and highly enriched uranium (HEU) items.

Effectiveness of simple control measures on methicillin-resistant Staphylococcus aureus infection status and characteristics with susceptibility patterns in a teaching hospital in Peshawar.

Science.gov (United States)

Rafiq, Muhammad Salman; Rafiq, Muhammad Imran; Khan, Taimur; Rafiq, Maria; Khan, Mah Muneer

2015-09-01

To determine the effectiveness of simple control measures on the infection status and characteristics of methicillin-resistant Staphylococcus aureus including susceptibility patterns among health professionals and patients in a teaching hospital. The cross-sectional study was conducted from September 2013 to January 2014, and comprised samples collected from healthcare personnel and patients in the various units of Khyber Teaching Hospital, Peshawar. The specimens were collected before and one month after the implementation of simple control measures for outbreak prevention of methicillin-resistant Staphylococcus aureus. These were tested for culture and antimicrobial susceptibility. Data about methicillin-sensitive and methicillin-resistant Staphylococcus aureus infection, wound characteristics and susceptibility patterns was collected and effectiveness of simple control measures was determined. SPSS 20 was used for statistical analysis. Of the total 390 isolates, 180(46.2%) were Staphylococcus aureus; 77(19.7%) from healthcare personnel and 103(26.4%) from patients. Of these, 164(42.1%) were methicillin-sensitive and 16(4.1%) were methicillin-resistant. Among the patients, 38(15.1%) methicillin-sensitive and 8(3.2%) methicillin-resistant isolates were recovered from wounds or skin and soft tissues. Pus with 33(13.1%) and 4(1.6%) cases respectively was the second most common source. Among methicillin-resistant isolates, resistance to Linezolid was 0%, all were resistant to Oxacillin, Cefoxitin, Amoxicillin, Cefotaxime and Cephradine, and resistance to both Co-Amoxiclav and Ciprofloxacin was 87.5%. After one month of implementation of simple control measures, the number of methicillin-resistant cases among healthcare professionals and patients dropped from 4(2.9%) and 7(10.8%) to 1(0.7%) and 5(2.7%), respectively. Methicillin-resistant and methicillin-sensitive Staphylococcus aureus differed in their anti-microbial susceptibility profiles. Selection of antibiotics

Portfolio of recent climate change studies utilizing AMS at ANTARES, ANSTO

International Nuclear Information System (INIS)

Child, D.; Smith, A.; Fink, D.; Hua, Q.; Elliot, G.; Williams, A.; Jacobsen, G.

2002-01-01

The application of Accelerator Mass Spectrometry (AMS) to the measurement of the radionuclides 14 C, 10 Be, 26 Al and 36 Cl has dramatically increased our understanding of factors that affect climate and has led to a greater understanding of natural processes. Using the ANTARES AMS facility at ANSTO we are able to analyse samples containing as few as 10 5 atoms of these radionuclides. Cosmogenic radionuclides produced by the interaction of cosmic rays with the upper atmosphere and exposed surface rocks are stored in natural archives. By measuring small variations in the concentrations of these isotopes over time, information can be inferred about the systems governing these changes. Over the last four years we have undertaken a broad range of climate change and environmental studies, based on the ultra-sensitive technique of accelerator mass spectrometry (AMS). Some specific examples of projects investigating the ice sheet at Law Dome, Antarctica and minerals extracted from geological surface formations will be given

A new dual injection system for AMS facility

International Nuclear Information System (INIS)

Liu Lin; Zhou Weijian; Cheng Peng; Yu Huagui; Chen Maobai

2007-01-01

In order to measure long-lived radioisotopes such as 10 Be with high sensitivity using an HVEE model 4130 AMS system, as well as to guarantee 14 C measurements of high precision, a new dual injection system for the AMS system is proposed. The proposal is to add a Wien filter located between the ion source system and the recombinator of the HVEE model 4130. When a pulsing voltage is optionally applied to the Wien filter, a sequential injection mode is turned on. The isotopes would alternately pass on different trajectories through the recombinator. When the pulsing voltage and magnetic field are turned off, the Wien filter acts as a field-free drift space and the standard simultaneous injection mode is on. Beam optics calculation show that the new dual injection system will increase the number of radio-nuclides which can be analyzed, keep the high precision capability for radiocarbon dating and achieve high sensitivity for 10 Be and 26 Al measurements, together with simplifying the layout as compared to existing dual-injector and dual high-energy beam line systems

First evidence of the conversion of paracetamol to AM404 in human cerebrospinal fluid

Directory of Open Access Journals (Sweden)

Sharma CV

2017-11-01

Full Text Available Chhaya V Sharma,1 Jamie H Long,2 Seema Shah,1 Junia Rahman,1 David Perrett,3 Samir S Ayoub,4 Vivek Mehta1 1Pain & Anaesthesia Research Centre, St Bartholomew’s and The Royal London Hospitals, Barts Health NHS Trust, London, UK; 2Barts & The London School of Medicine, Queen Mary University of London, London, UK; 3BioAnalytical Science, Barts & The London School of Medicine, Queen Mary University of London, London, UK; 4School of Health, Sport and Bioscience, Medicines Research Group, University of East London, London, UK Abstract: Paracetamol is arguably the most commonly used analgesic and antipyretic drug worldwide, however its mechanism of action is still not fully established. It has been shown to exert effects through multiple pathways, some actions suggested to be mediated via N-arachidonoylphenolamine (AM404. AM404, formed through conjugation of paracetamol-derived p-aminophenol with arachidonic acid in the brain, is an activator of the capsaicin receptor, TRPV1, and inhibits the reuptake of the endocannabinoid, anandamide, into postsynaptic ­neurons, as well as inhibiting synthesis of PGE2 by COX-2. However, the presence of AM404 in the central nervous system following administration of paracetamol has not yet been demonstrated in humans. Cerebrospinal fluid (CSF and blood were collected from 26 adult male patients between 10 and 211 minutes following intravenous administration of 1 g of paracetamol. Paracetamol was measured by high-performance liquid chromatography with UV detection. AM404 was measured by liquid chromatography-tandem mass spectrometry. AM404 was detected in 17 of the 26 evaluable CSF samples at 5–40 nmol⋅L–1. Paracetamol was measurable in CSF within 10 minutes, with a maximum measured concentration of 60 μmol⋅L–1 at 206 minutes. This study is the first to report on the presence of AM404 in human CSF following paracetamol administration. This may represent an important finding in our understanding of

Rapid method for the sequential measurement of isotopes of Am and Pu in liquid matrices by alpha spectrometry; Método rápido para la medida secuencial de isótopos de Am y Pu en matrices líquidas por espectrometría alfa

Energy Technology Data Exchange (ETDEWEB)

Mantero Cabrera, J.

2014-07-01

: In radiological emergencies it's necessary a fast response from the laboratories in the quantification of certain radionuclides, in order to take decisions. In these cases, is the reaction time the key parameter to consider (without neglecting the quality of the measurement). In this work, it is shown a method for aqueous matrices that generates Pu and Am isotopes sources in one single day of work, to be measured subsequently by alpha spectrometry. The developed methodology has been validated through its application to reference samples and also taking part intercom- parison exercises, having in both cases, satisfactory results. This way, we check the validity of this fast method that let us generate in 24 hours (since the sample arrives our laboratory), one measurement with a Minimun Detectable Activity (MDA) of about 0.004Bq/L for Pu and Am isotopes in liquid matrices. [Spanish] En situaciones de emergencia radiológica es muy común la necesidad de dar una respuesta rápida por parte de los laboratorios en la cuantificación de ciertos radionucleidos, de cara a la toma de decisiones. En estos casos, el tiempo de reacción es una variable fundamental a considerar (aunque obviamente sin dejar de lado la calidad en el resultado de la medida). En este trabajo se presenta un método para matrices acuosas que permite generar en una única jornada de trabajo, las fuentes de medida necesarias en la detección de isótopos de Pu y Am para ser medidas con posterioridad por espectrometría alfa. La metodología puesta a punto ha sido validada mediante su aplicación a muestras de referencia y mediante la participación en ejercicios de intercomparación, en ambos casos, con resultados satisfactorios. Queda así demostrada la validez de este método rápido que nos permite generar en 24 horas desde la recepción de la muestra, una medida en nuestros sistemas con una Actividad Mínima Detectable (AMD) de 0.004 Bq/L tanto para isótopos de Pu (238Pu, 239+240Pu) como de

New data acquisition system for AMS

Energy Technology Data Exchange (ETDEWEB)

Pfenninger, R. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

1997-09-01

A new data acquisition system based on a VME front-end computer, a Sun workstation and a PC has been installed. It is used for the acquisition of mainly AMS data, their graphical display, and storage of the data in a Oracle database. The measurement of magazines of 25 sample each is fully automated. Several data parameters such as transmission are regularly checked. In case of problems the operator is informed by optical and/or acoustical signals. Screens are updated automatically after every measurement cycle. (author) 1 fig.

AMS Weather Studies and AMS Ocean Studies: Dynamic, College-Level Geoscience Courses Emphasizing Current Earth System Data

Science.gov (United States)

Brey, J. A.; Geer, I. W.; Moran, J. M.; Weinbeck, R. S.; Mills, E. W.; Blair, B. A.; Hopkins, E. J.; Kiley, T. P.; Ruwe, E. E.

2008-12-01

AMS Weather Studies and AMS Ocean Studies are introductory college-level courses developed by the American Meteorological Society, with NSF and NOAA support, for local offering at undergraduate institutions nationwide. The courses place students in a dynamic and highly motivational educational environment where they investigate the atmosphere and world ocean using real-world and real-time environmental data. Over 360 colleges throughout the United States have offered these courses in course environments ranging from traditional lecture/laboratory to completely online. AMS Diversity Projects aim to increase undergraduate student access to the geosciences through implementation of the courses at minority-serving institutions and training programs for MSI faculty. The AMS Weather Studies and AMS Ocean Studies course packages consist of a hard-cover, 15-chapter textbook, Investigations Manual with 30 lab-style activities, and course website containing weekly current weather and ocean investigations. Course instructors receive access to a faculty website and CD containing answer keys and course management system-compatible files, which allow full integration to a college's e-learning environment. The unique aspect of the courses is the focus on current Earth system data through weekly Current Weather Studies and Current Ocean Studies investigations written in real time and posted to the course website, as well as weekly news files and a daily weather summary for AMS Weather Studies. Students therefore study meteorology or oceanography as it happens, which creates a dynamic learning environment where student relate their experiences and observations to the course, and actively discuss the science with their instructor and classmates. With NSF support, AMS has held expenses-paid course implementation workshops for minority-serving institution faculty planning to offer AMS Weather Studies or AMS Ocean Studies. From May 2002-2007, AMS conducted week-long weather workshops

Neutron and gamma-ray spectra of {sup 239}PuBe and {sup 241}AmBe

Energy Technology Data Exchange (ETDEWEB)

Vega-Carrillo, H.R. E-mail: rvega@cantera.reduaz.mx; Manzanares-Acuna, Eduardo; Becerra-Ferreiro, A.M.; Carrillo-Nunez, Aureliano

2002-08-01

Neutron and gamma-ray spectra of {sup 239}PuBe and {sup 241}AmBe were measured and their dosimetric features were calculated. Neutron spectra were measured using a multisphere neutron spectrometer with a {sup 6}LiI(Eu) scintillator. The {sup 239}PuBe neutron spectrum was measured in an open environment, while the {sup 241}AmBe neutron spectrum was measured in a closed environment. Gamma-ray spectra were measured using a NaI(Tl) scintillator using the same experimental conditions for both sources. The effect of measuring conditions for the {sup 241}AmBe neutron spectrum indicates the presence of epithermal and thermal neutrons. The low-resolution neutron spectra obtained with the multisphere spectrometer allows one to calculate the dosimetric features of neutron sources. At 100 cm both sources produce approximately the same count rate as that of the 4.4 MeV gamma-ray per unit of alpha emitter activity.

Review of magnetic susceptibility logging and its application to uranium exploration

International Nuclear Information System (INIS)

George, D.C.; Scott, J.H.

1982-01-01

Borehole measurement of magnetic susceptibility can show anomalies associated with mineralization or alteration. The detection of small anomalies is necessary, so efforts have been made in recent years to improve the sensitivity and the stability of magnetic susceptibility logging tools. Typical tools contain a single coil constructed as a solenoid wound on ferrite rods about 30cm long. The coil is heated to a constant temperature to reduce drift, and careful design is necessary to optimize temperature control and to maximize sensitivity. Measurements of coil resistance and inductance, which indicate conductivity and susceptibility, are made using a Maxwell bridge circuit. Circuit analysis shows that conductivity measurements are difficult and that stringent requirements are placed on phase stability of measurement circuitry. Corrections to the observed log are necessary to account for borehole size. The response of the tool to a thin zones of anomalous susceptibility is double peaked and a set of curves has been developed for interpretation. Calibrations of the tools are made by measuring the tool's response in models of known susceptibility

Application Research of Quasi-monochromatic X-ray Machine Replacing 241Am Radioactive Source in Thickness Measurement

Directory of Open Access Journals (Sweden)

LIN Hui1;XIAO Xue-fu2;HOU Yue-xin3;ZHAO Jing1;JIAN Li-min1

2014-02-01

Full Text Available In the research of BS-03 thickness detector, a self-designed quasi-monochromatic (50-60 keV X-ray machine was studied as a substitution to Am-241 low energy photon source（1.11×109 Bq）The range of output current, the attenuation of X rays through the steel plate, the aluminum plate, and the organic glass plate and stability of quasi-monochromatic X-ray machine was tested. The result showed that quasi-monochromatic X-ray machine could be an applicable replacement of Am-241 radioactive source.

Susceptibility for thin ideal media and eating styles

NARCIS (Netherlands)

Anschutz, Doeschka J; Engels, Rutger C M E; van Strien, Tatjana

This study examined the relations between susceptibility for thin ideal media and restrained, emotional and external eating, directly and indirectly through body dissatisfaction. Thin ideal media susceptibility, body dissatisfaction and eating styles were measured in a sample of 163 female students.

Recent results from the AMS-02 experiment

Directory of Open Access Journals (Sweden)

Vecchi Manuela

2015-01-01

Full Text Available The AMS-02 detector is a large acceptance magnetic spectrometer operating onboard the International Space Station since May 2011. The main goals of the detector are the search for antimatter and dark matter in space, as well as the measurement of cosmic ray composition and flux. Precise measurements of cosmic ray positrons and electrons are presented in this document, based on 41×109 events collected during the first 30 months of operations.

Decay counting in the age of AMS

International Nuclear Information System (INIS)

Arnold, J.R.

1987-01-01

Up to the advent of AMS, all the accomplishments of 14 C dating, and the studies of 10 Be and other long-lived radionuclides, were made by low-level decay counting, the technique pioneered by W.F. Libby. It will hardly be news to people at this conference that, while much was accomplished in the three decades when counting prevailed, the world has now changed decisively. I will try to give an account of where low-level counting was 'before the revolution', and of what its usefulness is today. There are still some remarkable examples of its application, the best being the neutrino experiment of Raymond Davis, and its potential successors. Some cosmogenic nuclides, whose half-lives are less than 10 3 yr, are still best measured by decay; this will continue unless the overall ion yield of AMS systems rises markedly from present levels. One long-lived nuclide, 53 Mn, is still best measured by neutron activation as 312-day 54 Mn, but this may not continue. (orig.)

Decay counting in the age of AMS

International Nuclear Information System (INIS)

Arnold, J.R.

1987-01-01

Up to the advent of AMS, all the accomplishments of 14 C dating, and the studies of 10 Be and other long-lived radionuclides, were made by low-level decay counting, the technique pioneered by W.F. Libby. It will hardly be news to people at this conference that, while much was accomplished in the three decades when counting prevailed, the world has now changed decisively. He will try to give an account of where low-level counting was before the revolution, and of what its usefulness is today. There are still some remarkable examples of its application, the best being the neutrino experiment of Raymond Davis, and its potential successors. Some cosmogenic nuclides, whose half-lives are less than 10 3 yr, are still best measured by decay; this will continue unless the overall ion yield of AMS systems rises markedly from present levels. One long-lived nuclide, 53 Mn, is still best measured by neutron activation as 312-day 54 Mn, but this may not continue

Microstructural evolution and Am migration behaviour in Am-containing fuels at the initial stage of irradiation

International Nuclear Information System (INIS)

Tanaka, Kosuke; Miwa, Shuhei; Sato, Isamu; Osaka, Masahiko; Hirosawa, Takashi; Obayashi, Hiroshi; Koyama, Shin-ichi; Yoshimochi, Hiroshi; Tanaka, Kenya

2010-01-01

In order to investigate the effect of americium addition to MOX fuels on the irradiation behaviour, the 'Am-1' programme is being conducted in JAEA. The Am-1 programme consists of two short-term irradiation tests of 10-minute and 24-hour irradiations and a steady-state irradiation test. The short-term irradiation tests were successfully completed and the post-irradiation examinations (PIE) are in progress. The PIE for Am-containing MOX fuels focused on the microstructural evolution and redistribution behaviour of Am at the initial stage of irradiation and the results to date are reported. The successful development of fabrication technology with remote handling and the evaluation of thermo-chemical properties based on the out-of-pile experiments are described with an emphasis on the effects of Am addition on the MOX fuel properties. (authors)

Measurements of thermodynamic constants of transuranic compounds to predict their geochemistry: Carbonate complexation of Np(V) and Am(III), hydrolysis of Pu(VI) and AM(III)

International Nuclear Information System (INIS)

Vitorge, P.

1984-02-01

This work is a part of a project to build a waste disposal and to model the behaviour of the radioactive elements. The contribution consists in the prediction of the geochemistry of actinides and the measurement of thermodynamic equilibrium constants, solubility products and redox potentials (E) used in the migration model. It has shown that literature can provide values for some of these constants and proposed theoretical E(pH) diagrams and solubilities of U, Np, Pu, Am. All transport will occur essentially in the aqueous phase leaching the repository site, where hydrolysis and carbonate complexation are important chemical reactions. The hydrolysis and carbonate complexation constants have already been reviewed. The experimental results are compared with the literature data which are usually chosen to predict the solubilities and the proportions of the different forms of these actinides in natural groundwaters

High-speed photometry of Gaia14aae: an eclipsing AM CVn that challenges formation models

Science.gov (United States)

Green, M. J.; Marsh, T. R.; Steeghs, D. T. H.; Kupfer, T.; Ashley, R. P.; Bloemen, S.; Breedt, E.; Campbell, H. C.; Chakpor, A.; Copperwheat, C. M.; Dhillon, V. S.; Hallinan, G.; Hardy, L. K.; Hermes, J. J.; Kerry, P.; Littlefair, S. P.; Milburn, J.; Parsons, S. G.; Prasert, N.; van Roestel, J.; Sahman, D. I.; Singh, N.

2018-05-01

AM CVn-type systems are ultracompact, hydrogen-deficient accreting binaries with degenerate or semidegenerate donors. The evolutionary history of these systems can be explored by constraining the properties of their donor stars. We present high-speed photometry of Gaia14aae, an AM CVn with a binary period of 49. 7 min and the first AM CVn in which the central white dwarf is fully eclipsed by the donor star. Modelling of the light curves of this system allows for the most precise measurement to date of the donor mass of an AM CVn, and relies only on geometric and well-tested physical assumptions. We find a mass ratio q = M2/M1 = 0.0287 ± 0.0020 and masses M1 = 0.87 ± 0.02 M⊙ and M2 = 0.0250 ± 0.0013 M⊙. We compare these properties to the three proposed channels for AM CVn formation. Our measured donor mass and radius do not fit with the contraction that is predicted for AM CVn donors descended from white dwarfs or helium stars at long orbital periods. The donor properties we measure fall in a region of parameter space in which systems evolved from hydrogen-dominated cataclysmic variables are expected, but such systems should show spectroscopic hydrogen, which is not seen in Gaia14aae. The evolutionary history of this system is therefore not clear. We consider a helium-burning star or an evolved cataclysmic variable to be the most likely progenitors, but both models require additional processes and/or fine-tuning to fit the data. Additionally, we calculate an updated ephemeris which corrects for an anomalous time measurement in the previously published ephemeris.

A high sensitivity SQUID-method for the measurement of magnetic susceptibility of small samples in the temperature range 1.5 K-40 K and application on small palladium particles

International Nuclear Information System (INIS)

Tu Nguyen Quang.

1979-01-01

In this paper a method is developed for magnetic susceptibility measurements which is superior to the common methods. The method is based on the SQUID-principle (Superconducting Quantum Interference Device) using the tunnel effect of a superconducting point contact and magnetic flux quantization for measuring electric and magnetic quantities. Due to this refined method susceptibility changes of very small palladium particles could be detected in the temperature range 1.5 K-40 K with respect to the bulk. In addition susceptibility differences of particle distributions with different means diameters (81 Angstroem and 65 Angstroem) have been measured for the first time. A quantitative comparison of the measurements with theoretical results shows satisfactory agreement. (orig./WBU) [de

AMS of actinides in ground- and seawater: a new procedure for simultaneous analysis of U, Np, Pu, Am and Cm isotopes below ppq levels

Energy Technology Data Exchange (ETDEWEB)

Quinto, Francesca; Lagos, Markus; Plaschke, Markus; Schaefer, Thorsten; Geckeis, Horst [Institut fuer Nukleare Entsorgung, KIT, Eggenstein-Leopoldshafen (Germany); Steier, Peter [VERA Laboratory, University of Vienna, Vienna (Austria)

2015-07-01

U-236, Np-237, Pu isotopes and Am-243 were determined in ground- and seawater samples at levels below ppq with a maximum sample size of 0.250 l. Such high sensitivity measurement was possible by using accelerator mass spectrometry (AMS) with an improved gas stripping and an additional high resolving magnet. The use of non-isotopic tracers was investigated in order to allow the determination of those nuclides, namely Np-237 and Am-243, for which isotopic tracers for mass spectrometry are rarely available. The actinides were concentrated from the sample matrix via iron hydroxide co-precipitation and measured sequentially without previous chemical separation from each other. The analytical method was validated with the analysis of IAEA 443 seawater Reference Material and applied to background samples from the Colloid Formation and Migration project at the Grimsel Test Site and to sea- and freshwater samples affected solely by global fallout. The sensitivity of the presented analytical method provides the capability to study the long-term release of actinide tracers in field experiments as well as the transport of actinides in a variety of environmental systems.

The new 6 MV multi-nuclide AMS facility at the University of Tsukuba

Science.gov (United States)

Sasa, Kimikazu; Takahashi, Tsutomu; Matsumura, Masumi; Matsunaka, Tetsuya; Satou, Yukihiko; Izumi, Daiki; Sueki, Keisuke

2015-10-01

The former accelerator mass spectrometry (AMS) system installed on the 12UD Pelletron tandem accelerator at the University of Tsukuba was completely destroyed by the Great East Japan Earthquake on 11 March 2011. A replacement has been designed and constructed at the university as part of the post-quake reconstruction project. It consists of a 6 MV Pelletron tandem accelerator, two multiple cathode AMS ion sources (MC-SNICSs), and a rare-particle detection system. The 6 MV Pelletron tandem accelerator will be applied not only to AMS, but also to areas such as nanotechnology, ion beam analysis, heavy ion irradiation, and nuclear physics. The rare-particle detection system will be capable of measuring environmental levels of long-lived radioisotopes of 10Be, 14C, 26Al, 36Cl, 41Ca, and 129I. It is also expected to measure other radioisotopes such as 32Si and 90Sr. The 6 MV Pelletron tandem accelerator was installed in the spring of 2014 at the University of Tsukuba. Routine beam delivery and AMS experiments will start in 2015.

Magnetic susceptibility measurement using 2D magnetic resonance imaging

Czech Academy of Sciences Publication Activity Database

Marcon, P.; Bartušek, Karel; Burdkova, M.; Dokoupil, Zdeněk

2011-01-01

Roč. 22, č. 10 (2011), 105702:1-8 ISSN 0957-0233 R&D Projects: GA ČR GAP102/11/0318; GA MŠk ED0017/01/01 Institutional research plan: CEZ:AV0Z20650511 Keywords : magnetic flux density * magnetic susceptibility * MRI * MR signal * reaction field Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering Impact factor: 1.494, year: 2011

The AMS [Accelerator Mass Spectrometer] program at LLNL

International Nuclear Information System (INIS)

Proctor, I.D.

1988-09-01

Livermore will have an operational Accelerator Mass Spectrometer (AMS) by mid-1989 as part of its new Multi-user Tandem Laboratory. The spectrometer was designed primarily for applications in archaeology and the geosciences and was co-funded by the University of California Regents. Radiological control for personnel protection, ion sources and injection systems, the tandem and all beam handling hardware are operated with a distributed processor computer control system. The Tandem is the former University of Washington injector FN which has been upgraded with Dowlish tubes, pelletron charging and SF 6 gas. Design goals for the AMS system, computer aided operation, automated measurement capability, initial results and some of our intended applications will be presented. 5 refs., 2 figs

Harmonic and static susceptibilities of YBa2Cu3O7

International Nuclear Information System (INIS)

Ishida, T.; Goldfarb, R.B.; Okayasu, S.; Kazumata, Y.; Franz, J.; Arndt, T.; Schauer, W.

1993-01-01

Intergranular properties of the sintered superconductor YBa 2 Cu 3 O 7 have been studied in terms of complex harmonic magnetic susceptibility χ n χ n ' - iχ n '' (n integer) as well as DC susceptibility χ dc . As functions of temperature T, χ 1 ' and χ 1 '' depend on both the AC magnetic-field amplitude H ac and the magnitude of a superimposed DC field H dc . Only odd-harmonic susceptibilities are observed below the critical temperature, T c , for zero H dc while both odd and even harmonics are observed for nonzero H dc . With T constant, odd-harmonic susceptibilities are even functions of H dc , whereas even-harmonic susceptibilities are odd functions of H dc . Experimental intergranular characteristics of χ n ' and χ n '' are in good agreement with theoretical predictions from a simplified Kim model of magnetization. In contrast, even-harmonic susceptibilities measured for a GdBa 2 Cu 3 O 7 thin film and an YBa 2 Cu 3 O 7 single crystal are not prominent due to missing weak links, whereas odd-harmonic susceptibilities are remarkable. A survey of several models for the harmonic response of superconductors is presented. The DC susceptibility curve for the zero-field-cooled YBa 2 Cu 3 O 7 sample, χ ZFC (T), has a two-step structure arising from intra- and inter-granular components, similar to χ 1 '. DC susceptibility measured upon warming, χ FCW (T), shows a negative peak near T c for the sample cooled rapidly in small DC fields. DC susceptibility measured upon cooling, χ FCC (T), does not show a peak. A negative peak is not seen in measurements on a powdered sample. The negative peak can be explained by intergranular flux depinning upon warming. (orig.)

Am-241 buildup in nematode organisms

International Nuclear Information System (INIS)

Martyushov, V.Z.; Tarasov, O.V.

1990-01-01

The process of Am-241 intake into earthworm organisms from chernozem leached in their presence in soil contaminated with this radionuclide is studied. The data on Am-241 buildup values during long-time radionuclide intake into earthworm organisms from soil are given. It s shown that Am-241 buildup in earthworm organisms do not exceed its concentration in soil for the whole observation period (as Am-241 presents in soil in state unavailable for animals). Intensive extraction of the radionuclide from the organisms is observed when earthworm contacts with soil are stopped

The contribution of AMS to geosciences

International Nuclear Information System (INIS)

Chivas, A.R.

1998-01-01

Full text: This presentation outlines some of the advances in AMS methods with emphasis on Australian examples and measurements using the accelerators at ANSTO and the Australian National University. Perhaps the best known of these techniques is the application of AMS 14 C dating which has the advantage of needing much smaller amounts of sample (typically 14 C determinations by β counting. AMS 14 C has been applied to dating an enormous array of materials including archaeological samples and sites, tree rings, ice cores, banding in coals and circulation and ventilation changes in the world's oceans. An exciting application of the measurement of the rare long-lived isotopes 10 Be, 26 Al and 36 Cl is in the relatively new field of cosmogenic exposure dating. Accumulation of these cosmogenically produced nuclides formed in-situ in exposed rock surfaces is used to estimate both the time of exposure of the rock surface and mean erosion rates. A large variety of landscape-related processes have been successfully addressed including weathering and sediment-transport rates and the ages of glacial retreat, tectonic uplift and lava eruptions. In the field of hydrology, 36 Cl studies of dissolved chloride have been used to successfully estimate the ages of ground waters and trace their origins. The tracing of atmospheric air masses that deliver rain and the origin of Australian salt lakes and continental salinisation using 36 Cl lead to important conclusions on the origin and residence time of chloride in the Australian landscape. The ultimate origin of the bulk of the surficial chloride in Australia is shown to be meteoric, and for the western part of the continent, a mean residence time of about 0.75 Ma pertains. The realisation of the long-term and continuing delivery of salts to the landscape needs recognition in planning strategies to combat salinisations of agricultural areas

The interpretation of archaeological dates from an AMS perspective

International Nuclear Information System (INIS)

Zoppi, U.; Sagona, A.; Siegele, R.; Hua, Q.; Jacobsen, G.; Lawson, E.M.

2001-01-01

The XVII century saw the establishment of the scientific method and scholars such as Galileo were giving excellent contributions to a variety of fields ranging from the natural sciences to the humanities. At the dawn of the new millenium, after a period of excessive specialization, the scientific climate is once again encouraging broad collaborations across different disciplines. For projects involving AMS measurements in general and radiocarbon dating in particular, the benefits of this new trend are numerous. For example, the full potential of the radiocarbon dating method can be exploited only through the mutual understanding of the problems related to sample selection, chemical preparation, AMS measurement, data analysis and interpretation. This paper is intended to enhance the exchange of information by reporting to our current and potential collaborators about the latest technical developments undertaken at the ANTARES AMS facility at ANSTO. Furthermore, we will present two splendid examples of collaborative research: the radiocarbon dating of a replica of a famous chesspiece and the archaeological investigations at the ancient settlement of Sos Hoyuk (north-eastern Anatolia, Turkey) where the multidisciplinary approach was the key to a better understanding of the social structure, settlement patterns, land use and cultural contact, especially with the lands of Trans-Caucasus. (author). 12 refs., 4 figs

32 CFR 37.805 - If I am awarding a TIA, what payment methods may I specify?

Science.gov (United States)

2010-07-01

... 32 National Defense 1 2010-07-01 2010-07-01 false If I am awarding a TIA, what payment methods may... Administrative Matters Payments § 37.805 If I am awarding a TIA, what payment methods may I specify? Your TIA may... measure of progress. Fixed-support TIAs must use this payment method and each measure of progress...

Magnetic susceptibility of free charge carriers in bismuth tellurides (Bi2Te3)

International Nuclear Information System (INIS)

Guha Thakurta, S.R.; Dutta, A.K.

1977-01-01

Principal magnetic susceptibilities of both p- and n-type Bi 2 Te 3 crystals have been measured over the range of temperature 90 deg K to 650 deg K. The observed susceptibilities are diamagnetic and temperature dependent. This temperature dependence has been attributed to the contribution of the free charge carriers to the susceptibilities. From the observed susceptibilities the carrier-susceptibilities have been separately obtained which are found to be paramagnetic. From the total carrier-susceptibilities, the susceptibilities of the carriers which are thermally liberated in the intrinsic region have been separated. From an analysis of the carrier-susceptibilities the band gap and its temperature coefficient have been found out and these compare favourably with those obtained from electrical measurements. (author)

Measurement of susceptibility artifacts with histogram-based reference value on magnetic resonance images according to standard ASTM F2119.

Science.gov (United States)

Heinrich, Andreas; Teichgräber, Ulf K; Güttler, Felix V

2015-12-01

The standard ASTM F2119 describes a test method for measuring the size of a susceptibility artifact based on the example of a passive implant. A pixel in an image is considered to be a part of an image artifact if the intensity is changed by at least 30% in the presence of a test object, compared to a reference image in which the test object is absent (reference value). The aim of this paper is to simplify and accelerate the test method using a histogram-based reference value. Four test objects were scanned parallel and perpendicular to the main magnetic field, and the largest susceptibility artifacts were measured using two methods of reference value determination (reference image-based and histogram-based reference value). The results between both methods were compared using the Mann-Whitney U-test. The difference between both reference values was 42.35 ± 23.66. The difference of artifact size was 0.64 ± 0.69 mm. The artifact sizes of both methods did not show significant differences; the p-value of the Mann-Whitney U-test was between 0.710 and 0.521. A standard-conform method for a rapid, objective, and reproducible evaluation of susceptibility artifacts could be implemented. The result of the histogram-based method does not significantly differ from the ASTM-conform method.

Calculation of the magnetic susceptibilities of transition metal monocarbides, mononitrides and monoxides

International Nuclear Information System (INIS)

Eibler, R.; Neckel, A.

1975-01-01

Results of Augmented Plane Wave (APW) band structure calculations are used to determine the magnetic susceptibilities of some transition metal monocarbides, mononitrides and monoxides (TiC, TiN, TiO, VC, VN, VO, NbC, NbN) assuming stoichiometric composition. Contributions to the susceptibility arising from the orbital para- and diamagnetism and the spin paramagnetism are determined separately. The orbital susceptibility terms are calculated by means of the model of Kubo and Obata. The calculated susceptibilities are compared with measured values. The approximations in the calculation of the orbital susceptibility terms are discussed especially with regard to the agreement between calculated and measured susceptibilities for the individual compounds. Similar calculations are performed for the susceptibilities of non-stoichiometric VCsub(x)-phase, for which APR-Virtual Crystal Approximation (VCA) band structure calculations are available. (author)

Innovative Instructional Tools from the AMS

Science.gov (United States)

Abshire, W. E.; Geer, I. W.; Mills, E. W.; Nugnes, K. A.; Stimach, A. E.

2016-12-01

Since 1996, the American Meteorological Society (AMS) has been developing online educational materials with dynamic features that engage students and encourage additional exploration of various concepts. Most recently, AMS transitioned its etextbooks to webBooks. Now accessible anywhere with internet access, webBooks can be read with any web browser. Prior versions of AMS etextbooks were difficult to use in a lab setting, however webBooks are much easier to use and no longer a hurdle to learning. Additionally, AMS eInvestigations Manuals, also in webBook format, include labs with innovative features and educational tools. One such example is the AMS Climate at a Glance (CAG) app that draws data from NOAA's Climate at a Glance website. The user selects historical data of a given parameter and the app calculates various statistics revealing whether or not the results are consistent with climate change. These results allow users to distinguish between climate variability and climate change. This can be done for hundreds of locations across the U.S. and on multiple time scales. Another innovative educational tool used in AMS eInvestigations Manuals is the AMS Conceptual Climate Energy Model (CCEM). The CCEM is a computer simulation designed to enable users to track the paths that units of energy might follow as they enter, move through and exit an imaginary system according to simple rules applied to different scenarios. The purpose is to provide insight into the impacts of physical processes that operate in the real world. Finally, AMS educational materials take advantage of Google Earth imagery to reproduce the physical aspects of globes, allowing users to investigate spatial relationships in three dimensions. Google Earth imagery is used to explore tides, ocean bottom bathymetry and El Nino and La Nina. AMS will continue to develop innovative educational materials and tools as technology advances, to attract more students to the Earth sciences.

Soil magnetic susceptibility as indicator of radioactive contamination

International Nuclear Information System (INIS)

Curda, S.

2006-01-01

Measurement of magnetic susceptibility is a method, which is used in many areas of research. The locality Ak-Tjuz is typical example of old ecological load. One of the negative effects represents radioactive contamination. This situation is caused by environmental disaster in 1964. For useful reparation it is really necessary to determinate the surface range of contamination. And measurement of the magnetic susceptibility could be the suitable method for that kind of monitoring. (author)

Is 8:30 a.m. Still Too Early to Start School? A 10:00 a.m. School Start Time Improves Health and Performance of Students Aged 13–16

Directory of Open Access Journals (Sweden)

Paul Kelley

2017-12-01

Full Text Available While many studies have shown the benefits of later school starts, including better student attendance, higher test scores, and improved sleep duration, few have used starting times later than 9:00 a.m. Here we report on the implementation and impact of a 10 a.m. school start time for 13 to 16-year-old students. A 4-year observational study using a before-after-before (A-B-A design was carried out in an English state-funded high school. School start times were changed from 8:50 a.m. in study year 0, to 10 a.m. in years 1–2, and then back to 8:50 a.m. in year 3. Measures of student health (absence due to illness and academic performance (national examination results were used for all students. Implementing a 10 a.m. start saw a decrease in student illness after 2 years of over 50% (p < 0.0005 and effect size: Cohen's d = 1.07, and reverting to an 8:50 a.m. start reversed this improvement, leading to an increase of 30% in student illness (p < 0.0005 and Cohen's d = 0.47. The 10:00 a.m. start was associated with a 12% increase in the value-added number of students making good academic progress (in standard national examinations that was significant (<0.0005 and equivalent to 20% of the national benchmark. These results show that changing to a 10:00 a.m. high school start time can greatly reduce illness and improve academic performance. Implementing school start times later than 8:30 a.m., which may address the circadian delay in adolescents' sleep rhythms more effectively for evening chronotypes, appears to have few costs and substantial benefits.

Physics of charged cosmic rays with the AMS experiment

Energy Technology Data Exchange (ETDEWEB)

Vialle, J.P

2001-01-01

The electrically charged cosmic rays contain very important information about the mechanisms of stars and galaxies and about primordial universe which cannot be found elsewhere. The AMS experiment aims at searching for primordial antimatter, non-baryonic dark matter, and at measuring with high statistics and high accuracy the electrically charged cosmic ray particles and light nuclei in the extraterrestrial space beyond the atmosphere. AMS is the first magnetic spectrometer which will be flown in space. It will be installed for 3 years on the international space station (ISS) in 2003. A test flight with the space shuttle DISCOVERY took place in June 1998 with a first detector and gave many results: best limit on the existence of antinuclei, fluxes of protons, leptons, and helium nuclei above the geomagnetic threshold, existence of a secondary flux below the geomagnetic threshold. These results are described below. The physics goal and perspectives for AMS on the space station with an improved detector are described as well. (author)

Optimization of a ΔE - E detector for 41Ca AMS

Science.gov (United States)

Hosoya, Seiji; Sasa, Kimikazu; Matsunaka, Tetsuya; Takahashi, Tsutomu; Matsumura, Masumi; Matsumura, Hiroshi; Sundquist, Mark; Stodola, Mark; Sueki, Keisuke

2017-09-01

A series of nuclides (14C, 26Al, and 36Cl) was measured using the 12UD Pelletron tandem accelerator before replacement by the horizontal 6 MV tandem accelerator at the University of Tsukuba Tandem Accelerator Complex (UTTAC). This paper considers the modification of the accelerator mass spectrometry (AMS) measurement parameters to suit the current 6 MV tandem accelerator setup (e.g., terminal voltage, detected ion charge state, gas pressure, and entrance window material in detector). The Particle and Heavy Ion Transport code System (PHITS) was also used to simulate AMS measurement to determine the best conditions to suppress isobaric interference. The spectra of 41Ca and 41K were then successfully separated and their nuclear spectra were identified; the system achieved a background level of 41Ca/40Ca ∼ 6 ×10-14 .

Constraints on Leptophilic Dark Matter from the AMS-02 Experiment

International Nuclear Information System (INIS)

Cavasonza, Leila Ali; Gast, Henning; Schael, Stefan; Krämer, Michael; Pellen, Mathieu

2017-01-01

The annihilation of dark matter particles in the Galactic halo of the Milky Way may lead to cosmic ray signatures that can be probed by the AMS-02 experiment, which has measured the composition and fluxes of charged cosmic rays with unprecedented precision. Given the absence of characteristic spectral features in the electron and positron fluxes measured by AMS-02, we derive upper limits on the dark matter annihilation cross section for leptophilic dark matter models. Our limits are based on a new background model that describes all recent measurements of the energy spectra of cosmic-ray positrons and electrons. For thermal dark matter relics, we can exclude dark matter masses below about 100 GeV. We include the radiation of electroweak gauge bosons in the dark matter annihilation process and compute the antiproton signal that can be expected within leptophilic dark matter models.

Constraints on Leptophilic Dark Matter from the AMS-02 Experiment

Energy Technology Data Exchange (ETDEWEB)

Cavasonza, Leila Ali; Gast, Henning; Schael, Stefan [I. Physikalisches Institut, RWTH Aachen University, D-52074 Aachen (Germany); Krämer, Michael [Institute for Theoretical Particle Physics and Cosmology, RWTH Aachen University, D-52074 Aachen (Germany); Pellen, Mathieu, E-mail: cavasonza@physik.rwth-aachen.de [Institut für Theoretische Physik und Astrophysik, Universität Würzburg, D-97074 Würzburg (Germany)

2017-04-10

The annihilation of dark matter particles in the Galactic halo of the Milky Way may lead to cosmic ray signatures that can be probed by the AMS-02 experiment, which has measured the composition and fluxes of charged cosmic rays with unprecedented precision. Given the absence of characteristic spectral features in the electron and positron fluxes measured by AMS-02, we derive upper limits on the dark matter annihilation cross section for leptophilic dark matter models. Our limits are based on a new background model that describes all recent measurements of the energy spectra of cosmic-ray positrons and electrons. For thermal dark matter relics, we can exclude dark matter masses below about 100 GeV. We include the radiation of electroweak gauge bosons in the dark matter annihilation process and compute the antiproton signal that can be expected within leptophilic dark matter models.

AMS/DOE Fellowship Recipients

Energy Technology Data Exchange (ETDEWEB)

Armstrong, Stephanie [American Meteorological Society, Boston, MA (United States)

2016-11-21

The AMS/DOE graduate fellowships were awarded to three students entering their first year of graduate study. The funds allowed each student to take a full course load during their first of year of graduate study which helps each of them to enter the professional, scientific community at an earlier date. Each recipient is academically outstanding, received glowing references of support and demonstrated their strong desire to perform scientific research. As part of the fellowship, each of the students was invited to attend the AMS Annual Meeting where they got to participate in the AMS student conference, attend scientific sessions and visit the exhibition hall. In addition, a student awards luncheon was held where each of the recipients got to meet their sponsor and receive a certificate.

Effect of feeding broilers diets differing in susceptible phytate content

Directory of Open Access Journals (Sweden)

Natalie K. Morgan

2016-03-01

Full Text Available Measurements of total phytate phosphorus content of diets may be deceptive as they do not indicate substrate availability for phytase; it may be that measurements of phytate susceptible to phytase effects are a more accurate measure of phosphorus (P availability to the bird. To verify this hypothesis, an experiment was conducted to compare diets formulated to contain either high or low susceptible phytate, supplemented with either 0 or 500 FTU/kg phytase. Susceptible phytate was determined by exposing the feed samples to conditions that mimicked the average pH of the proximal gastrointestinal tract (pH 4.5 and the optimum temperature for phytase activity (37 °C and then measuring phytate dissolved. Ross 308 birds (n = 240 were fed one of 4 dietary treatments in a 2 × 2 factorial design; 2 diets with high (8.54 g/kg, 57.90% of total phytate or low (5.77 g/kg, 46.33% of total phytate susceptible phytate, containing 0 or 500 FTU/kg phytase. Diets were fed to broilers (12 replicate pens of 5 birds per pen from d 0 to 28 post hatch. Birds fed diets high in susceptible phytate had greater phytate hydrolysis in the gizzard (P < 0.001, jejunum (P < 0.001 and ileum (P < 0.001 and resulting greater body weight gain (BWG (P = 0.015 and lower FCR (P = 0.003 than birds fed the low susceptible phytate diets, irrespective of phytase presence. Birds fed the high susceptible diets also had greater P solubility in the gizzard and Ca and P solubility in the jejunum and ileum (P < 0.05 and resulting greater tibia and femur Ca and P (P < 0.05 content than those fed the low susceptible diets. All the susceptible phytate was fully degraded in the tract in the absence of added phytase, suggesting the assay used in this study was able to successfully estimate the amount of total dietary phytate that was susceptible to the effects of phytase when used at standard levels. No interactions were observed between susceptible phytate and phytase on

Quantitative Susceptibility Mapping in Parkinson's Disease.

Science.gov (United States)

Langkammer, Christian; Pirpamer, Lukas; Seiler, Stephan; Deistung, Andreas; Schweser, Ferdinand; Franthal, Sebastian; Homayoon, Nina; Katschnig-Winter, Petra; Koegl-Wallner, Mariella; Pendl, Tamara; Stoegerer, Eva Maria; Wenzel, Karoline; Fazekas, Franz; Ropele, Stefan; Reichenbach, Jürgen Rainer; Schmidt, Reinhold; Schwingenschuh, Petra

2016-01-01

Quantitative susceptibility mapping (QSM) and R2* relaxation rate mapping have demonstrated increased iron deposition in the substantia nigra of patients with idiopathic Parkinson's disease (PD). However, the findings in other subcortical deep gray matter nuclei are converse and the sensitivity of QSM and R2* for morphological changes and their relation to clinical measures of disease severity has so far been investigated only sparsely. The local ethics committee approved this study and all subjects gave written informed consent. 66 patients with idiopathic Parkinson's disease and 58 control subjects underwent quantitative MRI at 3T. Susceptibility and R2* maps were reconstructed from a spoiled multi-echo 3D gradient echo sequence. Mean susceptibilities and R2* rates were measured in subcortical deep gray matter nuclei and compared between patients with PD and controls as well as related to clinical variables. Compared to control subjects, patients with PD had increased R2* values in the substantia nigra. QSM also showed higher susceptibilities in patients with PD in substantia nigra, in the nucleus ruber, thalamus, and globus pallidus. Magnetic susceptibility of several of these structures was correlated with the levodopa-equivalent daily dose (LEDD) and clinical markers of motor and non-motor disease severity (total MDS-UPDRS, MDS-UPDRS-I and II). Disease severity as assessed by the Hoehn & Yahr scale was correlated with magnetic susceptibility in the substantia nigra. The established finding of higher R2* rates in the substantia nigra was extended by QSM showing superior sensitivity for PD-related tissue changes in nigrostriatal dopaminergic pathways. QSM additionally reflected the levodopa-dosage and disease severity. These results suggest a more widespread pathologic involvement and QSM as a novel means for its investigation, more sensitive than current MRI techniques.

Counting efficiency of the lung monitor for sup 2 sup 4 sup 1 Am

CERN Document Server

Kinase, S; Sekiguchi, M

2003-01-01

The counting efficiencies of two lung monitor systems, phoswich detector system and germanium detector system, were measured for lungs and liver loaded with sup 2 sup 4 sup 1 Am in the Japan Atomic Energy Research Institute (JAERI) phantom. It was found that the germanium detector system for sup 2 sup 4 sup 1 Am loaded lungs counting gives the full-energy peak predominated by the absorption of the gamma-ray photon in a single photoelectric interaction and is less sensitive to sup 2 sup 4 sup 1 Am loaded liver. The sup 2 sup 4 sup 1 Am loaded lung activities could be reasonably estimated using germanium detector system rather than phoswich detector system.

Ferromagnetic resonance and transverse susceptibility measurements on particulate recording media (abstract)

Science.gov (United States)

Orth, Th.; Pelzl, J.; Chantrell, R. W.; Veitch, R.; Jakusch, H.

1993-05-01

The FMR absorption of different particulate recording tapes was investigated at microwave frequencies in the X band and Q band using temperatures from 70 to 400 K. The FMR spectra as a function of the external magnetic field were recorded for four different orientations of the static and high frequency magnetic fields with respect to the tape. Particular interest of the experimental and theoretical study was devoted to the interaction fields between the particles, texture effects within the tape sample and the effective anisotropy fields. Tape samples with different particle materials, varying packing densities and orientation ratios were prepared. The shape and line position of the FMR spectra obtained are strongly dependent on the pigment material and the tape parameters mentioned above. The experimental data are compared with theoretical calculations, based on a phenomenological model and a computer simulation. This comparison gives information on the orientational distribution of the particles, which is the most important source for inhomogeneous line broadening, the mean interaction, and anisotropy fields which govern the line position, the effective magnetization of the tape, and the relaxation time. The influence of the crystalline anisotropy can be investigated via temperature dependent measurements. The results are proved by additional transverse susceptibility measurements.

Magnetic susceptibility of 244Cm metal and 249Cf metal

International Nuclear Information System (INIS)

Fujita, D.K.; Parsons, T.C.; Edelstein, N.; Noe, M.; Peterson, J.R.

1975-07-01

The first magnetic susceptibility measurements made on the expanded fcc phase of 249 Cf metal are reported. Further measurements are needed on other Cf metal phases. Another measurement of the magnetic susceptibility of 244 Cm metal in a limited temperature range has been reported. The result does not agree with previously reported values. Further work is continuing on the synthesis of 244 Cm metal and 248 Cm metal and magnetic measurements on these samples. (auth)

Nature of the magnetic susceptibility of dysprosium. Paramagnetic susceptibility of dysprosium - yttrium alloys

International Nuclear Information System (INIS)

Demidov, V.G.; Levitin, R.Z.; Chistyakov, O.D.

1976-01-01

The paramagnetic susceptibility of single crystals of dysprosium-yttirum alloys is measured in the basal plane and along the hexagonal axis. It is shown that the susceptibility of the alloys obeys the Curie-Weiss law, the effective magnetic moments allong the different directions being the same and the paramagnetic Curie temperatures being different. The difference between the paramagnetic Curie temperatures in the basal plane and along the hexagonal axis is independent of the dysprosium concentration in the alloy. As a comparison with the theoretical models of magnetic anisotropy shows, this is an indication that the magnetic anisotropy of dysprosium - yttrium alloys is of a single-ion nature

Electrochemical investigations of La, Nd and Am in molten chloride salts in view of Am/Ln partitioning

International Nuclear Information System (INIS)

Pernel, C.; Serp, J.; Ougier, M.; Malmbeck, R.; Glatz, J.P.

2001-01-01

The electrochemical behaviour of La, Nd and Am has been investigated in molten LiCl-KCl eutectic. La shows a reversible single reduction/oxidation step controlled by mass transfer. The electrochemical reduction of Nd and Am proceeds via a two steps process, i.e. the reduction of trivalent species (Nd(III) and Am(III)) leading to Nd(II) and Am(II) species which are reduced at more negative potentials to form metallic deposits. Diffusion coefficients of La, Nd and Am have been calculated and are in reasonable agreement with literature data. Electro-depositions of La and Nd have been carried out onto solid Ni and liquid Cd cathodes. Much higher deposition efficiency is obtained for La compared to Nd on a solid cathode. This is an effect of the multi-valent nature of Nd in the chloride melts. (author)

Electrochemical investigations of La, Nd and Am in molten chloride salts in view of Am/Ln partitioning

Energy Technology Data Exchange (ETDEWEB)

Pernel, C.; Serp, J.; Ougier, M.; Malmbeck, R.; Glatz, J.P. [European Commission, JRC, ITU, Karlsruhe (Germany)

2001-07-01

The electrochemical behaviour of La, Nd and Am has been investigated in molten LiCl-KCl eutectic. La shows a reversible single reduction/oxidation step controlled by mass transfer. The electrochemical reduction of Nd and Am proceeds via a two steps process, i.e. the reduction of trivalent species (Nd(III) and Am(III)) leading to Nd(II) and Am(II) species which are reduced at more negative potentials to form metallic deposits. Diffusion coefficients of La, Nd and Am have been calculated and are in reasonable agreement with literature data. Electro-depositions of La and Nd have been carried out onto solid Ni and liquid Cd cathodes. Much higher deposition efficiency is obtained for La compared to Nd on a solid cathode. This is an effect of the multi-valent nature of Nd in the chloride melts. (author)

14C-AMS at the Leibniz-Labor: radiometric dating and isotope research

International Nuclear Information System (INIS)

Grootes, Pieter M.; Nadeau, Marie-Josee; Rieck, Anke

2004-01-01

The Leibniz-Labor was founded to provide radiometric dating services using AMS and measured over 15 000 samples and 26 800 targets up to September 2002. Research and development have primarily been directed at improving the efficiency and reliability of AMS measurements, optimising existing sample preparation procedures for AMS and developing new ones. The standard chemical pre-treatment of organic radiocarbon samples produces often two fractions: one from which contaminants have been removed, and one in which they have been enriched. Dating both fractions reveals the degree of sample contamination. This provides a useful indication of the reliability of the sample age obtained and of the environmental conditions where the sample was taken. Upgrades to reduce maintenance include replacing four cryo- by turbo pumps, installing a deionizer loop, which keeps conductivity between 100 and 150 μS/cm to control corrosion, in the closed cooling water circuit, and developing a new sample wheel, which holds target holders with a groove and spring clip. Long term stability is demonstrated by the results obtained for IAEA reference materials, measured routinely and regularly over the years. Tests made as part of the FIRI project demonstrate that reliable measurements down to <0.1 mg C can be made

Determination of Pu, Am and Cm in Environmental Samples

Energy Technology Data Exchange (ETDEWEB)

Lujaniene, G. [SRI Centre for Physical Sciences and Technology, Vilnius (Lithuania)

2013-07-15

The determination of actinides in the environmental samples at a lower detection limit is required for monitoring purposes and for environmental research. The method for Pu, Am and Cm measurements in soil and sediment samples provides high recoveries and good decontamination from interfering radionuclides. The main steps of the method involve digestion of the samples, separation of radionuclides from matrix using the TOPO /cyclohexane extraction and final purification using extraction Eichrom resins (TEVA, TRU). The accuracy and precision of Pu, Am and Cm analyses were tested using IAEA RM No 135, NIST SRM No 4350b, No 4357 and in intercomparison runs organized by the Riso National Laboratory, Denmark, and in the proficiency tests organized by National Physical Laboratory, UK. The method was applied for measurement of radionuclides in aerosol samples (ashes {approx}30 g), bottom sediments (50-80 g dr. wt) and soil (including Chernobyl soil) samples. (author)

The new 6 MV multi-nuclide AMS facility at the University of Tsukuba

Energy Technology Data Exchange (ETDEWEB)

Sasa, Kimikazu, E-mail: ksasa@tac.tsukuba.ac.jp; Takahashi, Tsutomu; Matsumura, Masumi; Matsunaka, Tetsuya; Satou, Yukihiko; Izumi, Daiki; Sueki, Keisuke

2015-10-15

The former accelerator mass spectrometry (AMS) system installed on the 12UD Pelletron tandem accelerator at the University of Tsukuba was completely destroyed by the Great East Japan Earthquake on 11 March 2011. A replacement has been designed and constructed at the university as part of the post-quake reconstruction project. It consists of a 6 MV Pelletron tandem accelerator, two multiple cathode AMS ion sources (MC-SNICSs), and a rare-particle detection system. The 6 MV Pelletron tandem accelerator will be applied not only to AMS, but also to areas such as nanotechnology, ion beam analysis, heavy ion irradiation, and nuclear physics. The rare-particle detection system will be capable of measuring environmental levels of long-lived radioisotopes of {sup 10}Be, {sup 14}C, {sup 26}Al, {sup 36}Cl, {sup 41}Ca, and {sup 129}I. It is also expected to measure other radioisotopes such as {sup 32}Si and {sup 90}Sr. The 6 MV Pelletron tandem accelerator was installed in the spring of 2014 at the University of Tsukuba. Routine beam delivery and AMS experiments will start in 2015.

The new 6 MV multi-nuclide AMS facility at the University of Tsukuba

International Nuclear Information System (INIS)

Sasa, Kimikazu; Takahashi, Tsutomu; Matsumura, Masumi; Matsunaka, Tetsuya; Satou, Yukihiko; Izumi, Daiki; Sueki, Keisuke

2015-01-01

The former accelerator mass spectrometry (AMS) system installed on the 12UD Pelletron tandem accelerator at the University of Tsukuba was completely destroyed by the Great East Japan Earthquake on 11 March 2011. A replacement has been designed and constructed at the university as part of the post-quake reconstruction project. It consists of a 6 MV Pelletron tandem accelerator, two multiple cathode AMS ion sources (MC-SNICSs), and a rare-particle detection system. The 6 MV Pelletron tandem accelerator will be applied not only to AMS, but also to areas such as nanotechnology, ion beam analysis, heavy ion irradiation, and nuclear physics. The rare-particle detection system will be capable of measuring environmental levels of long-lived radioisotopes of "1"0Be, "1"4C, "2"6Al, "3"6Cl, "4"1Ca, and "1"2"9I. It is also expected to measure other radioisotopes such as "3"2Si and "9"0Sr. The 6 MV Pelletron tandem accelerator was installed in the spring of 2014 at the University of Tsukuba. Routine beam delivery and AMS experiments will start in 2015.

Measurement and analysis of the 241Am(n,γ) cross section at the CERN nTOF facility

International Nuclear Information System (INIS)

Fraval, Kevin

2013-01-01

In the context of the current nuclear technology, the radiotoxicity of the spent fuel of a typical PWR reactor is dominated by minor actinides for times greater than 10 4 years. In particular, 241 Am and its 432 years half-life is responsible for about half of the minor actinide content of a PWR spent fuel. This thesis work consisted in measuring and analysing the 241 Am(n,γ) cross section at the CERN n T OF facility. After selecting exclusively the events obtained with lead shielding in front of the C 6 D 6 detectors, the amplitude-energy calibration has to be adjusted with time, by using a photon coming from the 27 Al(α,p) 30 Si * reaction. Histogram extraction included applying a weighting function (obtained by MCNP simulation), a dead time correction, and a normalization to the compound nucleus excitation energy. The background corrected spectra were normalized relatively to the 4.9 eV resonance on 197 Au. Finally, the resonance analysis was performed using the SAMMY code. The extracted thermal value is 678±68 barns, the uncertainty being mostly due to the large background level. The resolved range was extended from 150 eV to 320 eV, with a total of 192 resonances that had to be added of heavily modified. The unresolved region was analysed up to 150 keV, yielding a larger average cross section than previously evaluated below 20 keV. (author) [fr

Detection of Pu in Pacific Ocean water with AMS related to the Fukushima accident

Energy Technology Data Exchange (ETDEWEB)

Hain, Karin; Faestermann, Thomas; Fimiani, Leticia; Guzman, Jose Manuel; Korschinek, Gunther; Kortmann, Florian; Lierse v Gostomski, Christoph; Ludwig, Peter [TUM (Germany); Golser, Robin; Steier, Peter [Universitaet Wien (Austria); Yamada, Masatoshi [Hirosaki University (Japan)

2016-07-01

The concentration of plutonium (Pu) and its isotopic ratios were determined by accelerator mass spectrometry (AMS) in Pacific Ocean water samples. The isotopic ratios {sup 240}Pu/{sup 239}Pu and {sup 241}Pu/{sup 239}Pu can be used to identify a possible release of Pu into the ocean by the Fukushima accident. {sup 241}Pu from fallout of nuclear weapon testings has already significantly decayed. {sup 241}Am, the daughter nuclide of {sup 241}Pu, causes isobaric background on {sup 241}Pu in mass-spectrometric measurements. Therefore, Am and Pu had to be separated chemically using extraction chromatography. The method was verified by analyzing certified reference material. 12 sea water samples, collected at different depths, were prepared at the Radiochemie Muenchen. The concentration of Pu was measured with AMS at the Maier-Leibnitz-Laboratory in Munich and the Vienna Environmental Research Laboratory (VERA). After a short motivation related to the Fukushima accident, the chemical separation method will be presented. Preliminary results of the distribution of Pu in ocean water will be discussed.

Magnetic Susceptibilities as they appeared to me - An Amperian approach

Energy Technology Data Exchange (ETDEWEB)

Van den Bosch, A.

2008-08-15

Starting from scratch, the book narrates a systematic story of the basic ideas you need for understanding quasi static magnetic susceptibilities. The story leans on the authors 25 year experience measuring susceptibilities following the Faraday technique (related with solid state physics, radiation effects, materials and magneto chemistry). The base of magnetism, the current-current interaction, is the linkage between the topics treated. The number of mathematical equations are reduced to a minimum and can be skipped without losing the thread of the story. The story is positive towards the sound bases of magnetism. However, room is left for the interpretation of measuring data. As the word susceptibility covers different meanings, the story answers for different situations the question: what is susceptible to what for creating what?

Magnetic Susceptibilities as they appeared to me - An Amperian approach

International Nuclear Information System (INIS)

Van den Bosch, A.

2008-01-01

Starting from scratch, the book narrates a systematic story of the basic ideas you need for understanding quasi static magnetic susceptibilities. The story leans on the authors 25 year experience measuring susceptibilities following the Faraday technique (related with solid state physics, radiation effects, materials and magneto chemistry). The base of magnetism, the current-current interaction, is the linkage between the topics treated. The number of mathematical equations are reduced to a minimum and can be skipped without losing the thread of the story. The story is positive towards the sound bases of magnetism. However, room is left for the interpretation of measuring data. As the word susceptibility covers different meanings, the story answers for different situations the question: what is susceptible to what for creating what?

A study of internal dosimetry of Am-241 and Sr-90 by dismantling of a nuclear installation; Eine Fallstudie zur internen Dosimetrie von Am-241 und Sr-90 bei Rueckbau einer kerntechnischen Anlage

Energy Technology Data Exchange (ETDEWEB)

Froning, M.; Hill, P. [Forschungszentrum Juelich GmbH (Germany). Geschaeftsbereich Sicherheit und Strahlenschutz

2016-07-01

During dismantling operation in former nuclear facility routine incorporation monitoring had been part of the safety measures. For an occupational radiation worker positive measurements results for {sup 241}Am, {sup 90}Sr and {sup 137}Cs were obtained after the end of the working period. Follow up monitoring had been performed assessing urine and faeces samples for {sup 241}Am and {sup 90}Sr as well as in-vivo measurements for {sup 137}Cs. Ingestion could be proven as incorporation path. The internal dose assessment according to GMBl 2007{sup [1]} finally yielded internal dose at 13 μSv.

Lattice thermal expansions of NpN, PuN and AmN

International Nuclear Information System (INIS)

Takano, Masahide; Akabori, Mitsuo; Arai, Yasuo; Minato, Kazuo

2008-01-01

Lattice parameters of NpN, PuN and AmN were measured by a high temperature X-ray diffraction method from room temperature up to 1478 K. Linear thermal expansions of these TRU nitrides were determined as a function of temperature. The average coefficients of linear thermal expansion from 293 to 1273 K were 8.8, 11.1 and 11.2 x 10 -6 K -1 for NpN, PuN and AmN, respectively. The instantaneous coefficient of thermal expansion either at 293 or at 1273 K against the reciprocal decomposition temperature under 1 atm of nitrogen showed a linear relationship for TiN, ZrN, HfN, UN, NpN and PuN. Based on this relationship, the decomposition temperature of AmN was roughly predicted to be 2700 K

[Effects of grain-sized moxibustion from 7 am to 9 am on circadian rhythm of inflammatory factor IL-6 in rats with rheumatoid arthritis].

Science.gov (United States)

Ma, Wenbin; Liu, Xuguang; Qin, Yong; Zhou, Haiyan; Yang, Xin

2016-04-01

To explore the rhythm regulatory mechanism of interleukin-6 (IL-6) in the process of moxibustion for rheumatoid arthritis (RA). A total of 144 Sprague-Dawley (SD) rats were randomly divided into a blank group, a model group, a moxibustion group, a sham operation group, an operation group, an operation+moxibustion group, 24 rats in each one. Each group was divided into 4 time points (0:00 am, 6:00' am, 12:00 am, 6:00 pm), 6 rats in each time point. The Light-Dark 12 : 12 was given in all rats for light-dark cycle. Except the blank group, rats in the remaining groups were treated with intracutaneous injection of freund's complete adjuvant at right-side foot to establish the model of RA. After the model establishment, bilateral adrenal, glands were removed in the operation group and operation + moxibustion group, while those in the sham operation group were not removed with identical operation procedure. Rats in the moxibustion group and operation + moxibustion group were treated with grain-sized moxibustion from 7:00 am to 9:00 am at "Shenshu" (BL 23) and "Zusanli" (ST 36) once everyday, 6 times were taken as one session and 3 sessions were required tatclly, while rats in the remaining groups received identical fixation without moxibustion. The general health state and foot volume of rats were measured before model establishment, after establishment and after treatment. After treatment, rats were sacrificed at each time point to collect the blood sample and measure the content of IL-6 by using enzymne-immunoassay method. Compared with the blank group, the foot swelling in the model group was obviously increased (Pcircadian rhythm (Pcircadian. rhythm (Pcircadian rhythm (P circadian rhythm in RA rats; with the complete hypothalamic-pituitary-adrenal axis, moxibustion is likely to regulate the circadian rhythm of IL-6 to play an important role of anti-inflammatory effect in RA rats.

Analysis of Protection Measures for Naval Vessels Berthed at Harbor Against Terrorist Attacks

Science.gov (United States)

2016-06-01

of discriminating neutral vessels from threats. A naval vessel berthed at harbor is more susceptible to attack than a vessel in open seas. The...discriminating neutral vessels from threats. A naval vessel berthed at harbor is more susceptible to attack than a vessel in open seas. The chances of...this thesis. He was a source of inspiration, encouragement, and reassurance. Captain Jeffery E. Kline, I am really thankful to you for your ideas

AMS with light nuclei at small accelerators

Science.gov (United States)

Stan-Sion, C.; Enachescu, M.

2017-06-01

AMS applications with lighter nuclei are presented. It will be shown how Carbon-14, Boron-10, Beryllium-10, and Tritium-3 can be used to provide valuable information in forensic science, environmental physics, nuclear pollution, in material science and for diagnose of the plasma confinement in fusion reactors. Small accelerators are reliable, efficient and possess the highest ion beam transmissions that confer high precision in measurements.

Adaptation of the Activity Measure Post-Acute Care (AM-PAC) from English to Mandarin using the dual-panel translation approach

DEFF Research Database (Denmark)

Chang, Feng-Hang; Liou, Tsan-Hon; Brodersen, John

2017-01-01

translated using the dual-panel method. The translated AM-PAC was tested in 550 Chinese-speaking rehabilitation outpatients. Floor and ceiling effects were evaluated and internal consistency was assessed using Cronbach's alpha. Spearman correlation was used to assess the concurrent validity of the AM...

Analysis of Windscale and Bikini atoll sediments for Am-242m

International Nuclear Information System (INIS)

Beasley, T.M.

1976-01-01

Bowen and Livingston have recently reported the existence of 242 Am in both 1962 nuclear test debris and in a marine algae sample (kelp) contaminated by nuclear fuel reprocessing wastes. The presence of 242m Am (T 1/2 = 152y) was deduced by measuring its daughter product, 242C m. In the case of the fallout debris, the long decay time (25 years) between collection and analysis was argued to preclude the possibility of unsupported 242 Cm being present in the sample. The non-adherence to simple radiometric decay of the 242 Cm measured in two aliquots of the algae sample suggested that a small percentage of the isotope (≈ 3%) was in fact supported by its longer lived parent

In-flight operations and status of the AMS-02 silicon tracker

CERN Document Server

Ambrosi, G; Battiston, R; Bertucci, b B; Choumilov, E; Choutko, V; Crispoltoni, M; Delgado, C; Duranti, M; Donnini, F; D'Urso, D; Fiandrini, cE; Formato, V; Graziani, M; Habiby, M; Haino, S; Ionica, M; Kanishchev, K; Nozzoli, F; Oliva, c A; Paniccia, M; Pizzolotto, C; Pohl, c M; Qin, X; Rapin, d D; Saouter, P; Tomassetti, N; Vitale, V; Vitillo, c S; Wu, X; Zhang, Z; Zuccon, P

2016-01-01

The AMS-02 detector is a large acceptance magnetic spectrometer operating on the International Space Station since May 2011. More than 60 billion events have been collected by the instrument as of today. One of the key subdetectors of AMS-02 is the microstrip silicon Tracker, designed to precisely measure the trajectory and absolute charge of cosmic rays in the GeV-TeV energy range. In addition, with the magnetic field, is also measuring the particle magnetic rigidity, defined as R = pc/Ze, and the sign of the charge. This report presents the Tracker on-line operations and calibration during the first four years of data taking in space. The track reconstruction efficiency and the resolution will be also reviewed.

FoAM Kernow Activity Report 2016

OpenAIRE

Griffiths, Amber; Griffiths, David

2016-01-01

This review shows selected projects from the FoAM Kernow studio in 2016. FoAM is a network of transdisciplinary labs at the intersection of art, science, nature and everyday life. FoAM’s members are generalists - people who work across disparate fields in an entangled, speculative culture. Research and creative projects at FoAM combine elements of futurecrafting, citizen science, prototyping, experience design and process facilitation to re-imagine possible futures, and artistic experime...

FoAM Kernow Activity Report 2017

OpenAIRE

Griffiths, Amber; Weatherill, Aidan; Griffiths, David

2017-01-01

This review shows selected projects from the FoAM Kernow studio in 2017. FoAM is a network of transdisciplinary labs at the intersection of art, science, nature and everyday life. FoAM’s members are generalists - people who work across disparate fields in an entangled, speculative culture. Research and creative projects at FoAM combine elements of futurecrafting, citizen science, prototyping, experience design and process facilitation to re-imagine possible futures.

Adsorption behavior of Am(III) on granite

International Nuclear Information System (INIS)

Zhang Yingjie; Feng Xiaogui; Liang Junfu; Chen Jing; Su Rui; Wang Ju; Liu Chunli

2009-01-01

The adsorption behavior of Am(III) on granite (sampled from drilling well BS01 at Beishan (BS) area--a potential candidate site for China's high-level radioactive waste repository, the granite sample's depth about 300 m) was studied in BS03 well groundwater by a batch technique at (25±1) degree C. The influences of pH, sulphate ion, total carbonate ion, humic acid, and concentration of the Am(III) on the adsorption behavior were also studied, and the possible adsorption mechanism was discussed. Experimental results show that the adsorption distribution rate of Am(III) on granite increases with increasing pH of aqueous phase. The chemical composition of the groundwater is the main factor which influences the species of Am(III) and adsorption behavior. The adsorption mechanism of Am(III) on granite is surface complexation. The adsorption isotherm of Am(III) on granite can be described by Freundlich's equation. (authors)

Biosorption of 241Am by Candida sp

International Nuclear Information System (INIS)

Luo Shunzhong; Zhang Taiming; Liu Ning; Yang Yuanyou; Jin Jiannan; Hua Xinfeng

2003-01-01

The biosorption of radionuclide 241 Am from solutions by Candida sp., and the influences of experimental conditions on the adsorption were studied. The results showed that the adsorption equilibrium was achieved within 4h and the optimum pH=2. No significant differences on 241 Am biosorption were observed at 10-45 degree C, or challenged with Au 3+ or Ag + , even 1500 times or 4500 times over 241 Am, respectively. The adsorption rate could reach 97.8% by dry Candida sp. of 0.82 g/L in 241 Am solutions (pH=2) of 5.6-111 MBq/L (44.04-873.0 μg/L) (C 0 ), with maximum adsorption capacity (W) of 63.5 MBq/g (501.8 μg/g), implying that the removal of 241 Am by Candida sp. from solutions was feasible. The relationship between activities (C 0 ) and adsorption capacities (W) of 241 Am indicated that the biosorption process could be described by Langmuir adsorption isotherm

{sup 53}Mn and {sup 60}Fe measurements in lunar samples by means of accelerator mass spectrometry (AMS)

Energy Technology Data Exchange (ETDEWEB)

Fimiani, Leticia; Faestermann, Thomas; Gomez Guzman, Jose Manuel; Hain, Karin; Korschinek, Gunther; Ludwig, Peter [Fakultaet fuer Physik, Technische Universitaet Muenchen, D-85748, Garching (Germany); Herzog, Gregory; Ligon, Bret; Park, Jisun [Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, NJ 08854 (United States); Knie, Klaus [GSI, Planckstrasse 1, D-64291, Darmstadt (Germany); Rugel, Georg [Fakultaet fuer Physik, Technische Universitaet Muenchen, D-85748, Garching (Germany); Forschungszentrum Dresden-Rossendorf, D-01314, Dresden (Germany)

2012-07-01

Cook et al, 40th LPSC 1129 (2009) reported a concentration of 14{sup +9}{sub -6} dpm {sup 60}Fe/[kg Ni] (T{sub 1/2}=2.62.10{sup 6}a) in a surface sample of the Apollo 12 12025/8 drive tube. This value is higher than the one expected due to galactic or solar cosmic ray production and may suggest the deposition of supernova debris on the lunar surface about 2 Ma ago. In order to try to reproduce this result, new measurements were made in material from the same core and position. To widen the search for supernova debris, we also analyzed four near-surface samples of lunar drive tube 15008; and one each from the skim, scoop and under-boulder samples 69921/41/61 via AMS in the Maier Leibnitz Laboratorium in Garching, Germany. The measuring technique and the preliminary results are discussed.

Susceptibility to Peer Influence: Using a Performance-Based Measure to Identify Adolescent Males at Heightened Risk for Deviant Peer Socialization

Science.gov (United States)

Prinstein, Mitchell J.; Brechwald, Whitney A.; Cohen, Geoffrey L.

2011-01-01

A substantial amount of research has suggested that adolescents' attitudes and behaviors are influenced by peers; however, little is known regarding adolescents' individual variability, or susceptibility, to peer influence. In this study, a performance-based index from an experimental paradigm was used to directly measure adolescents'…

The AMS experiment: first results and physics prospects

International Nuclear Information System (INIS)

Vialle, J.P.

2000-04-01

The main physics goal of the AMS experiment is the search for primordial antimatter, non-baryonic dark matter, and the measurement with high statistics and high accuracy of the electrically charged cosmic ray particles and light nuclei in the extraterrestrial space beyond the atmosphere. AMS is the first magnetic spectrometer which will be flown in space. It will be installed for 3 years on the international space station (ISS) in 2003. A precursor flight with the space shuttle DISCOVERY took place in June 1998. 100 millions particles were recorded during the test flight and unexpected physics results were observed on fluxes of protons, electrons, positrons, and helium nuclei. These results are described below, and the physics prospects for the second phase of the experiment on the space station as well. (author)

Brain Potentials and Personality: A New Look at Stress Susceptibility.

Science.gov (United States)

1987-09-01

disinhibition (Dis) measures a hedonistic , extraverted lifestyle including drinking, parties, sex, and gambling; boredom susceptibility (BS) indicates an...adventure seeking; ES = Experience seeking; Dis = Disinhibition; BS = Boredom susceptibility. 1 14 I N i*5’ Table 4 Correlation of Auditory Evoked...20. aTAS = Thrill and adventure seeking; ES = Experience seeking; Dis = Disinhibition; BS = Boredom susceptibility. < .05. 15 I The present study

Development of a nano-tesla magnetic field shielded chamber and highly precise AC-susceptibility measurement coil at μK temperatures

Science.gov (United States)

Kumar, Anil; Prakash, Om; Ramakrishanan, S.

2014-04-01

A special sample measurement chamber has been developed to perform experiments at ultralow temperatures and ultralow magnetic field. A high permeability material known as cryoperm 10 and Pb is used to shield the measurement space consisting of the signal detecting set-up and the sample. The detecting setup consists of a very sensitive susceptibility coil wound on OFHC Cu bobbin.

Preparing and measuring ultra-small radiocarbon samples with the ARTEMIS AMS facility in Saclay, France

Energy Technology Data Exchange (ETDEWEB)

Delque-Kolic, E., E-mail: emmanuelle.delque-kolic@cea.fr [LMC14, CEA Saclay, Batiment 450 Porte 4E, 91191 Gif sur Yvette (France); Comby-Zerbino, C.; Ferkane, S.; Moreau, C.; Dumoulin, J.P.; Caffy, I.; Souprayen, C.; Quiles, A.; Bavay, D.; Hain, S.; Setti, V. [LMC14, CEA Saclay, Batiment 450 Porte 4E, 91191 Gif sur Yvette (France)

2013-01-15

The ARTEMIS facility in Saclay France measures, on average, 4500 samples a year for French organizations working in an array of fields, including environmental sciences, archeology and hydrology. In response to an increasing demand for the isolation of specific soil compounds and organic water fractions, we were motivated to evaluate our ability to reduce microgram samples using our standard graphitization lines and to measure the graphite thus obtained with our 3MV NEC Pelletron AMS. Our reduction facility consists of two fully automated graphitization lines. Each line has 12 reduction reactors with a reduction volume of 18 ml for the first line and 12 ml for the second. Under routine conditions, we determined that we could reduce the samples down to 10 {mu}g of carbon, even if the graphitization yield is consequently affected by the lower sample mass. Our results when testing different Fe/C ratios suggest that an amount of 1.5 mg of Fe powder was ideal (instead of lower amounts of catalyst) to prevent the sample from deteriorating too quickly under the Cs+ beam, and to facilitate pressing procedures. Several sets of microsamples produced from HOxI standard, international references and backgrounds were measured. When measuring {sup 14}C-free wood charcoal and HOxI samples we determined that our modern and dead blanks, due to the various preparation steps, were of 1.1 {+-} 0.8 and 0.2 {+-} 0.1 {mu}g, respectively. The results presented here were obtained for IAEA-C1, {sup 14}C-free wood, IAEA-C6, IAEA-C2 and FIRI C.

Preparing and measuring ultra-small radiocarbon samples with the ARTEMIS AMS facility in Saclay, France

International Nuclear Information System (INIS)

Delqué-Količ, E.; Comby-Zerbino, C.; Ferkane, S.; Moreau, C.; Dumoulin, J.P.; Caffy, I.; Souprayen, C.; Quilès, A.; Bavay, D.; Hain, S.; Setti, V.

2013-01-01

The ARTEMIS facility in Saclay France measures, on average, 4500 samples a year for French organizations working in an array of fields, including environmental sciences, archeology and hydrology. In response to an increasing demand for the isolation of specific soil compounds and organic water fractions, we were motivated to evaluate our ability to reduce microgram samples using our standard graphitization lines and to measure the graphite thus obtained with our 3MV NEC Pelletron AMS. Our reduction facility consists of two fully automated graphitization lines. Each line has 12 reduction reactors with a reduction volume of 18 ml for the first line and 12 ml for the second. Under routine conditions, we determined that we could reduce the samples down to 10 μg of carbon, even if the graphitization yield is consequently affected by the lower sample mass. Our results when testing different Fe/C ratios suggest that an amount of 1.5 mg of Fe powder was ideal (instead of lower amounts of catalyst) to prevent the sample from deteriorating too quickly under the Cs+ beam, and to facilitate pressing procedures. Several sets of microsamples produced from HOxI standard, international references and backgrounds were measured. When measuring 14 C-free wood charcoal and HOxI samples we determined that our modern and dead blanks, due to the various preparation steps, were of 1.1 ± 0.8 and 0.2 ± 0.1 μg, respectively. The results presented here were obtained for IAEA-C1, 14 C-free wood, IAEA-C6, IAEA-C2 and FIRI C.

AMS Days: "the results are phenomenal"

CERN Multimedia

2015-01-01

Following the conclusion of the successful AMS Days at CERN (see here), we sat down with leading minds in space science and particle physics to discuss their thoughts on the recent positron-excess results as well as the future of the AMS physics programme.   Samuel Ting, AMS spokesperson: Roberto Battiston, President of the Italian Space Agency (ASI): William H. Gerstenmaier, Human Exploration and Operations Directorate, NASA: Edward C. Stone (Caltech), Voyager 1 and 2 principal investigator:

Forgery at the Snite Museum of Art? Improving AMS Radiocarbon Dating at the University of Notre Dame

Science.gov (United States)

Troyer, Laura; Bagwell, Connor; Anderson, Tyler; Clark, Adam; Nelson, Austin; Skulski, Michael; Collon, Philippe

2017-09-01

The Snite Museum of Art recently obtained several donations of artifacts. Five of the pieces lack sufficient background information to prove authenticity and require further analysis to positively determine the artwork's age. One method to determine the artwork's age is radiocarbon dating via Accelerator Mass Spectrometry (AMS) performed at the University of Notre Dame's Nuclear Science Laboratory. Samples are prepared by combustion of a small amount of material and subsequent reduction to carbon into an iron powder matrix (graphitization). The graphitization procedure affects the maximum measurement rate, and a poor graphitization can be detrimental to the AMS measurement of the sample. Previous graphitization procedures resulted in a particle current too low or inconsistent to optimize AMS measurements. Thus, there was a desire to design and refine the graphitization system. The finalized process yielded physically darker samples and increased sample currents by two orders of magnitude. Additionally, the first testing of the samples was successful, yet analysis of the dates proved inconclusive. AMS measurements will be performed again to obtain better sampling statistics in the hopes of narrowing the reported date ranges. NSF and JINA-CEE.

It's About Time: Interpreting AMS Antimatter Data in Terms of Cosmic Ray Propagation

CERN Multimedia

CERN. Geneva

2015-01-01

If cosmic ray positrons come from a secondary origin, then their production spectrum is correlated with the production spectrum of other secondary particles such as boron and antiprotons through scattering cross sections measured in the laboratory. This allows to define a first-principle upper bound on the positron flux at the Earth, independent of propagation model assumptions. Using currently available B/C and antiproton/proton data, we show that the positron flux reported by AMS is consistent with the bound and saturates it at high energies. This coincidence is a compelling indication for a secondary source. We explain how improved AMS measurements of the high energy boron, antiproton, and secondary radioactive nuclei fluxes can corroborate or falsify the secondary source hypothesis. Assuming that the positrons are secondary, we show that AMS data imply a propagation time in the Galaxy of order 1Myr or less for cosmic rays with magnetic rigidity > 300 GV. This corresponds to an average traversed interstel...

AMS studies in Portuguese variscan granites

Science.gov (United States)

Sant'Ovaia, Helena; Martins, Helena; Noronha, Fernando

2014-05-01

A large volume of Variscan granitic rocks outcrop in Central Iberian Zone which are well documented concerning geological mapping, petrography and geochemistry but whose magnetic characteristics and fabric remain unknown. In this study we summarize the available AMS data from approximately 644 sampling stations (5152 samples) on different massifs of Variscan Portuguese granites. Despite their different geological, petrographic and geochemical characteristics, magnetic susceptibility (K) values obtained for the majority of the studied granites range from 15 to 300 × 10-6 SI. The dominant paramagnetic behaviour of the granite bodies reflects the presence of ilmenite as the main iron oxide. This feature indicates the reduced conditions involved in the granite melt formation during the Variscan orogeny. The two-mica granites show K values ranging between 15 to 70 × 10-6 SI which are lower than values displayed by the biotite-rich facies scattered within the interval of 70 and 300 × 10-6 SI. The magnetite-bearing granites are scarce but represented in Lavadores, Gerês and Manteigas. Even so, only the Lavadores body could be considered as a true magnetite-type granite (K >3.0 × 10-3 SI) in face of its K, comprised between 1550 and 19303 × 10-6 SI. Magnetic anisotropy can be used as a "marker" for the deformation experienced by granite mushes during their crustal emplacement and further cooling. Magnetic anisotropy can thus be correlated with the finite deformation of a rock, as record by mineral fabrics. Post-tectonic granites, such as those from Vila Pouca de Aguiar, Pedras Salgadas, Caria, Vila da Ponte, Chaves and Lamas de Olo, have a magnetic anisotropy <2.5% which corresponds to a deformation hardly visible to the naked eye. Nevertheless, at microscopic scale, these granites display almost ubiquitous magmatic to submagmatic microstructures (rare wavy extinction in quartz, erratic subgrain boundaries in quartz and, eventually, folded or kinked biotites). For

Activity determination of the Am-241 sources from radioactive lightning rods

International Nuclear Information System (INIS)

Minematsu, Denise; Dellamano, Jose Claudio; Ferreira, Robson de Jesus

2009-01-01

The authorization for manufacture commerce and installation of radioactive lightning rods, in Brazil, was lifted in 1989 by the National Nuclear Energy Commission - CNEN (Resolution no 4/89). Since this date, these devices have been replaced and have been sent to the Institutes subordinated to the CNEN, amongst them the Nuclear and Energy Research Institute - IPEN-CNEN/SP. Radioactive Waste Management Laboratory - RWML of the IPEN - CNEN/SP had received, approximately, 16,000 units up to the end of 2008. The radioactive lightning rod is constituted in its majority, for a central metallic rod, where two or three metallic plates are mounted. In these plates, on average, six Am-241 sources are fixed. The process used for the radioactive lightning rods treatment is the dismantling of the device and the withdrawal of the sources from the metallic plates. The activity values of the lightning rods sources, supplied by the manufacturers, vary from two to three orders of magnitude and therefore it is necessary to characterize these sources. This paper describes the methodology used to measure the actual activity of each Am-241 sources extracted from the radioactive lightning rods. The first step was to sample tens of Am-241 sources and carry out the activity measurements for further use in the system calibration. The equipment used in this first stage was a gamma spectrometer, previously calibrated with an Am-241 standard source, in agreement with the same arrangement and same geometry in the measures of the sources. Results show that there are sources with similar activity values of those supplied by the manufacturers, but there are also sources with no activity - or also activity very low compared with the expected value -, as well as sources contend other radionuclides. (author)

Thermal conductivities of (ZrxPu(1-x)/2Am(1-x)/2)N solid solutions

International Nuclear Information System (INIS)

Nishi, Tsuyoshi; Takano, Masahide; Akabori, Mitsuo; Arai, Yasuo

2011-01-01

The thermal conductivity of Zr-based transuranium (TRU) nitride solid solutions is important for designing subcritical cores in nitride-fueled ADS. Some results have been reported concerning the thermal conductivities of (Zr,Pu)N. However, there have been no experimental data on the thermal conductivities of Zr-based nitride solid solutions containing MA. In this study, the authors prepared sintered samples of (Zr x Pu (1-x)/2 Am (1-x)/2) N (x=0.0, 0.58, 0.80) solid solutions. The thermal diffusivity and heat capacity of (Zr x Pu (1-x)/2 Am (1-x)/2) N solid solutions were measured using a laser flash method and drop calorimetry, respectively. Thermal conductivities were determined from the measured thermal diffusivities, heat capacities and bulk densities over a temperature range of 473 to 1473 K. The thermal conductivities of (Zr 0.58 Pu 0.21 Am 0.21 )N and (Zr 0.80 Pu 0.10 Am 0.10 )N solid solutions were found to be higher than that of (Pu 0.5 Am 0.5 )N due to the high thermal conductivity of ZrN as the principal component, although they were lower than that of ZrN due to the impurifying effect of the transuranium elements. Thus, the thermal conductivities of (Zr x Pu (1-x)/2 Am (1-x)/2) N solid solutions increased with increasing ZrN concentration. Moreover, in order to help to promote the design study of nitride-fueled ADS, the thermal conductivity of the (Zr x Pu (1-x)/2 Am (1-x)/2) N solid solutions were fitted to an equation using the least squares method. (author)

Plant uptake and transport of 241Am

International Nuclear Information System (INIS)

Wallace, A.; Romney, E.M.; Mueller, R.T. Sr.; soufi, S.M.

1981-01-01

We conducted several experiments with 241 Am to obtain a more complete understanding of how this transuranium element is absorbed and transported in plants. In a plant species (Tamarix pentandra Pall.) that has salt glands in the leaves excreting NaCl and other ions, 241 Am was not pumped through these glands. Cyanide, which forms complexes with any metals, when applied to a calcareous soil, greatly increased the transport of 241 Am into stems and leaves of bush bean plants. Radioactive cyanide ( 14 C) was also transported to leaves and stems. When radish was grown in both calcareous and noncalcareous soils, 241 Am appeared to be fixed on the peel so firmly that it was resistant to removal by HNO 3 washing. The chelating agent DTPA induced increased transport of 241 Am to leaves and into the fleshy roots of the radish. Data for Golden Cross hybrid corn grown in solution culture showed at least seven times as much 241 Am transport to the xylem exudatields are corrected by recovery of added tracers

Using "I Am Moving, I Am Learning" to Increase Quality Instruction in Head Start Classrooms

Science.gov (United States)

Allar, Ishonté; Jones, Emily; Bulger, Sean

2018-01-01

Quality teacher-child interactions are characteristic of effective classrooms resulting in benefits for all children, but may be particularly important for children from low-income families. The purpose of this study was to explore the perception of Illinois Head Start teachers related to how "I am Moving, I am Learning" (IMIL) could…

Elements in biological AMS

International Nuclear Information System (INIS)

Vogel, J.S.; McAninch, J.; Freeman, S.

1996-08-01

AMS (Accelerator Mass Spectrometry) provides high detection sensitivity for isotopes whose half-lives are between 10 years and 100 million years. 14 C is the most developed of such isotopes and is used in tracing natural and anthropogenic organic compounds in the Earth's biosphere. Thirty-three elements in the main periodic table and 17 lanthanides or actinides have long lived isotopes, providing potential tracers for research in elemental biochemistry. Overlap of biologically interesting heavy elements and possible AMS tracers is discussed

Tobacco Marketing, E-cigarette Susceptibility, and Perceptions among Adults.

Science.gov (United States)

Nicksic, Nicole E; Snell, L Morgan; Rudy, Alyssa K; Cobb, Caroline O; Barnes, Andrew J

2017-09-01

Understanding the impact of tobacco marketing on e-cigarette (EC) susceptibility and perceptions is essential to inform efforts to mitigate tobacco product burden on public health. Data were collected online in 2016 from 634 conventional cigarette (CC) smokers and 393 non-smokers using a convenience sample from Amazon Mechanical Turk. Logistic regression models, stratified by smoking status and adjusted for socio-demographics, examined the relationship among tobacco advertisements and coupons, EC and CC susceptibility, and EC perceptions. Among non-smokers, increased exposure to tobacco advertising and receiving tobacco coupons was significantly related to measures of EC and CC susceptibility (p marketing reduce EC use by decreasing susceptibility.

Magnetic susceptibility of YbN

International Nuclear Information System (INIS)

Zhou, Y.; Bowen, S.P.; Koelling, D.D.; Monnier, R.

1991-01-01

Applying the Zwicknagl, Zevin, and Fulde (ZZF) approximation for the spectral densities of the occupied and empty f states resulting from a degenerate-Anderson-impurity model, which incorporates crystal fields, we compute the low-temperature magnetic susceptibility of YbN. The model, in which each crystal-field level couples to the band states with its own hybridization function, has previously been successfully applied without the ZZF approximation to explain the specific-heat structure at low temperatures. The ZZF approximation removes the spurious zero-temperature behavior of the parent noncrossing approximation for the susceptibility. Surprisingly, even at the low crystal-field degeneracy (N=2) of YbN, the Shiba relation is very nearly satisfied. The appropriate experimental impurity susceptibility for comparison is extracted from the measurement by removing an empirical exchange interaction. The resultant Kondo temperature (T 0 =8.49 K) is consistent with previous specific-heat estimates (10--11 K), and the agreement with experiment is good

21 CFR 822.24 - What are my responsibilities once I am notified that I am required to conduct postmarket...

Science.gov (United States)

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false What are my responsibilities once I am notified that I am required to conduct postmarket surveillance? 822.24 Section 822.24 Food and Drugs FOOD AND... SURVEILLANCE Responsibilities of Manufacturers § 822.24 What are my responsibilities once I am notified that I...

Contamination on AMS Sample Targets by Modern Carbon is Inevitable

NARCIS (Netherlands)

Paul, Dipayan; Been, Henk A.; Aerts-Bijma, Anita Th.; Meijer, Harro A.J.

Accelerator mass spectrometry (AMS) measurements of the radiocarbon content in very old samples are often challenging and carry large relative uncertainties due to possible contaminations acquired during the preparation and storage steps. In case of such old samples, the natural surrounding levels

Effect of structural transition on magnetic susceptibility of tantalum carbide

International Nuclear Information System (INIS)

Lipatnikov, V.N.; Gusev, A.I.; Rempel', A.A.; Shvejkin, G.P.

1987-01-01

Ordering of carbon atoms and vacancies in nonmetal sublattice of TaC y is investigated for the first time by methods of magnetic susceptibility and structural neutron diffraction analysis. Measurements of magnetic susceptibility were conducted on high-sensitive magnetic scales in temperature interval of 300 - 1300 K with holding at each temperature up to the establishment of constant, nonchanging in the course of time value of susceptibility x. When investigating x-hardened tantalum carbide within the interval of TaC 0.82 - TaC 0.85 compositions under the conditions of slow heating, it was observed nonrecorded earlier irreversible decrease of susceptibility at temperature of 960 - 1000 K. With further temperature increase T>T tr it was observed at first even and than uneven increase of x value at a temperature of T tr equal to 1090, 1130 and 1150 K for TaC 0.82 , TaC 0.83 and TaC 0.85 respectively. The measuring of magnetic susceptibility of the same samples at temperature decrease reveals the presence of susceptibility temperature hysteresis in the interval of 1070 - 1090, 1100 - 1130 and 1120 - 1150 for TaC 0.82 , TaC 0.83 and TaC 0.85 . Reversible susceptibility jump corresponding to the temperature hysteresis range at dependences of x(T), is connected with equilibrium structural phase transition of order-disorder

Calibration Human Voxel Phantoms for In Vivo Measurement of ''241 Am in Bone at the Whole Body Counter Facility of CIEMAT

International Nuclear Information System (INIS)

Moraleda, M.; Lopez, M. A.; Gomez Ros, J. M.; Navarro, T.; Navarro, J. F.

2002-01-01

The Whole Body Counting facility of CIEMAT is capable of carrying out In-Vivo measurements of radionuclides emitting X-rays and low energy gamma radiation internally deposited in the body. The system to use for this purpose consists of flour Low energy Germanium (LeGe) Camberra detectors working in the energy range from 10 to 1000 keV. Physical phantoms with a known contamination in the organ of interest are normally used for the calibration of the LEGe detection system. In this document we present a calibration method using the Monte Carlo technique (MCNP4C) over a voxel phantom obtained from a computerized tomography of a real human head. The phantom consists of 104017 (43x59x41) cubic voxels, 4 mn on each side, os specific tissues, but for this simulation only two types are taken into account: adipose tissue and hard bone. The skull is supposed to be contaminated with ''241 Am and the trajectories of the photons are simulated till they reach the germanium detectors. The detectors were also simulated in detail to obtain a good agreement with the reality. In order to verify the accuracy of this procedure to reproduce the experiments, the MCNP results are compared with laboratory measurements of a head phantom simulating an internal contamination of 1000 Bq of ''241 Am deposited in bone. Different relative positions source-detector were tried to look for the best counting geometry for measurement of a contaminated skull. Efficiency values are obtained and compared, resulting in the validation of the mathematical method for the assessment of internal contamination of American deposited in skeleton. (Author) 16 refs

The Earth Observing System AM Spacecraft - Thermal Control Subsystem

Science.gov (United States)

Chalmers, D.; Fredley, J.; Scott, C.

1993-01-01

Mission requirements for the EOS-AM Spacecraft intended to monitor global changes of the entire earth system are considered. The spacecraft is based on an instrument set containing the Advanced Spaceborne Thermal Emission and Reflection radiometer (ASTER), Clouds and Earth's Radiant Energy System (CERES), Multiangle Imaging Spectro-Radiometer (MISR), Moderate-Resolution Imaging Spectrometer (MODIS), and Measurements of Pollution in the Troposphere (MOPITT). Emphasis is placed on the design, analysis, development, and verification plans for the unique EOS-AM Thermal Control Subsystem (TCS) aimed at providing the required environments for all the onboard equipment in a densely packed layout. The TCS design maximizes the use of proven thermal design techniques and materials, in conjunction with a capillary pumped two-phase heat transport system for instrument thermal control.

How AMS dating changed my life

International Nuclear Information System (INIS)

Spriggs, M.

2001-01-01

Accelerator mass spectrometry (AMS) radiocarbon dating was developed in the late 1970s. Remembering back to a time before AMS dating was available to archaeologists is a bit like trying to remember how we ever survived without desktop computers, email or automatic teller machines. My own particular interest in AMS dating was an inevitable offshoot from my long-established interest in chronometric hygiene, or 'getting the dates right'. In this paper I attempt to illustrate that accurate dating matters, by discussing some examples of AMS dating projects with which I have been involved over the last six years or so. In relation to these projects, AMS has given us the ability to date sites which we could not before. It has enabled us to provide more detailed stratigraphies when datable materials are rare. It has allowed us to date materials we could not date before, such as rock art pigments. It has been able to provide indications of the degree of site disturbance in the absence of other obvious forms of evidence. And it has allowed us to assess claims for the antiquity of particular material cultural types and faunal introductions. (author). 41 refs

New results from the
 AMS experiment on the International Space Station

CERN Multimedia

CERN. Geneva

2016-01-01

The Alpha Magnetic Spectrometer, AMS, is a general purpose high energy particle phys- ics detector. It was installed on the International Space Station, ISS, on 19 May 2011 to conduct a unique long duration mission of fundamental physics research in space. Knowledge of the precise rigidity dependence of the proton and helium flux is important in understanding the origin, acceleration, and propagation of cosmic rays. Pre- cise measurements of the proton and of the helium flux in primary cosmic rays with rigidities (momentum/charge) up to the TV scale are presented and the detailed varia- tion with rigidity of the flux spectral indices will be discussed. A precision measurement by AMS of the antiproton flux and antiproton-to-proton ratio in primary cosmic rays in the rigidity range from 1 to 450 GV is presented. This measurement increases the precision of the previous observations and significantly extends their rigidity range. It shows that the antiproton-to-proton ratio remains constant above ∼60 GV. In a...

Upgrading of the AMS facility at the Koffler 14UD Pelletron accelerator

CERN Document Server

Berkovits, D; Bordeanu, C; Ghelberg, S; Hass, M; Heber, O; Paul, M; Shahar, Y; Verri, G; 10.1016/j.nimb.2004.04.033

2004-01-01

The AMS facility based on a 14UD Pelletron tandem accelerator has been upgraded in recent years to support an active and diversified research program. A new dedicated AMS ion source beam line merging at 45 degrees with the existing injection line through a 45 degrees electrostatic deflector is in operation. The multi-sample high- intensity Cs sputter ion source stands on a separate 120 kV platform and is remote-controlled through a hybrid infrared-fiber-optics link operated either manually or by the accelerator-control computer, ensuring safe and reliable operation. Independent current preamplifiers are used in Faraday cup current readings down to the pA range. The accelerator computer-control system was upgraded to Lab View 6.1, allowing a PC server to control and read out all hardware components while one or more remote PC clients run the AMS software. Ad hoc sequences of commands, written in a script macro language, are run from a client computer to perform an automated AMS measurement. The present capabil...

Journal of Earth System Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

Oriented samples of sediments from Ariyalur Group, Cauvery Basin, south India, were studied for low field anisotropy of magnetic susceptibility (AMS) measurements to unravel the magnetic fabrics and paleocurrent directions. The results of AMS parameters of the sediments indicate primary depositional fabrics for Sillakkudi ...

Quantitative susceptibility mapping (QSM) as a means to measure brain iron? A post mortem validation study

Science.gov (United States)

Langkammer, Christian; Schweser, Ferdinand; Krebs, Nikolaus; Deistung, Andreas; Goessler, Walter; Scheurer, Eva; Sommer, Karsten; Reishofer, Gernot; Yen, Kathrin; Fazekas, Franz; Ropele, Stefan; Reichenbach, Jürgen R.

2012-01-01

Quantitative susceptibility mapping (QSM) is a novel technique which allows determining the bulk magnetic susceptibility distribution of tissue in vivo from gradient echo magnetic resonance phase images. It is commonly assumed that paramagnetic iron is the predominant source of susceptibility variations in gray matter as many studies have reported a reasonable correlation of magnetic susceptibility with brain iron concentrations in vivo. Instead of performing direct comparisons, however, all these studies used the putative iron concentrations reported in the hallmark study by Hallgren and Sourander (1958) for their analysis. Consequently, the extent to which QSM can serve to reliably assess brain iron levels is not yet fully clear. To provide such information we investigated the relation between bulk tissue magnetic susceptibility and brain iron concentration in unfixed (in situ) post mortem brains of 13 subjects using MRI and inductively coupled plasma mass spectrometry. A strong linear correlation between chemically determined iron concentration and bulk magnetic susceptibility was found in gray matter structures (r = 0.84, p < 0.001), whereas the correlation coefficient was much lower in white matter (r = 0.27, p < 0.001). The slope of the overall linear correlation was consistent with theoretical considerations of the magnetism of ferritin supporting that most of the iron in the brain is bound to ferritin proteins. In conclusion, iron is the dominant source of magnetic susceptibility in deep gray matter and can be assessed with QSM. In white matter regions the estimation of iron concentrations by QSM is less accurate and more complex because the counteracting contribution from diamagnetic myelinated neuronal fibers confounds the interpretation. PMID:22634862

Measurement of weak electric currents in copper wire phantoms using MRI: influence of susceptibility enhancement.

Science.gov (United States)

Huang, Ruiwang; Posnansky, Oleg; Celik, Abdullah; Oros-Peusquens, Ana-Maria; Ermer, Veronika; Irkens, Marco; Wegener, H-Peter; Shah, N Jon

2006-08-01

The use of magnetic resonance imaging (MRI)-based methods for the direct detection of neuronal currents is a topic of intense investigation. Much experimental work has been carried out with the express aim of establishing detection thresholds and sensitivity to flowing currents. However, in most of these experiments, magnetic susceptibility enhancement was ignored. In this work, we present results that show the influence of a susceptibility artefact on the detection threshold and sensitivity. For this purpose, a novel phantom, consisting of a water-filled cylinder with two wires of different materials connected in series, was constructed. Magnitude MR images were acquired from a single slice using a gradient-echo echo planar imaging (EPI) sequence. The data show that the time course of the detected MR signal magnitude correlates very well with the waveform of the input current. The effect of the susceptibility artefacts arising from the two different wires was examined by comparing the magnitudes of the MR signals at different voxel locations. Our results indicate the following: (1) MR signal enhancement arising from the magnetic susceptibility effect influences the detection sensitivity of weak current; (2) the detection threshold and sensitivity are phantom-wire dependent; (3) sub-mu A electric current detection in a phantom is possible on a 1.5-T MR scanner in the presence of susceptibility enhancement.

Spatial statistical analysis of contamination level of 241Am and 239Pu, Thule, North-West Greenland

Energy Technology Data Exchange (ETDEWEB)

Strodl Andersen, J. (JSA EnviroStat (Denmark))

2011-10-15

A spatial analysis of data on radioactive pollution on land at Thule, North-West Greenland is presented. The data comprises levels of 241Am and 239,240Pu on land. Maximum observed level of 241Am is 2.8x105 Bq m-2. Highest levels were observed near Narsaarsuk. This area was also sampled most intensively. In Groennedal the maximum observed level of 241Am is 1.9-104 Bq m-2. Prediction of the overall amount of 241Am and 239,240Pu is based on grid points within the range from the nearest measurement location. The overall amount is therefore highly dependent on the model. Under the optimal spatial model for Narsaarsuk, within the area of prediction, the predicted total amount of 241Am is 45 GBq and the predicted total amount of 239,240Pu is 270 GBq. (Author)

Cosmic gamma ray detection and discovery potential with the AMS-2 spectrometer; Detection de rayons {gamma} cosmiques et potentiel de decouvertes avec le spectrometre AMS-02

Energy Technology Data Exchange (ETDEWEB)

Girard, L

2004-12-15

Yet designed to measure charged component of the cosmic rays, the foreseen Alpha Magnetic Spectrometer (AMS-02) could also release {gamma}-ray studies, in the energy range from GeV to TeV, using the tracker system, for {gamma}-rays converted in e{sup +}e{sup -} pair, and the electromagnetic calorimeter. In the first part of the thesis are described the calibrations and the performances of the engineering model of the calorimeter, obtained from the analysis of data taken during a test-beam performed at CERN in July 2002. In the second part of the thesis, the AMS-02 discovery potential for {gamma}-astrophysics is presented. While exposure maps of the {gamma}--sky are computed for one year of data taking with the {gamma}--detectors, the acceptance of the calorimeter is obtained from Monte-Carlo simulations. The AMS-02 potential is then estimated for signals from the Vela pulsar and for some supersymmetric signals from the Galactic Center. (author)

Study of the properties of the Am-O system in view of the transmutation of Am 241 in fast reactors

International Nuclear Information System (INIS)

Casalta, S.

1996-04-01

To reduce the long term toxicity of Am 241 it was considered to transmute this isotope in fast reactor. The first part of this thesis is an introduction at this problem. In the second part we give the experimental techniques used for the realisation of an AmO 2 -MgO target (powder metallurgy under inert, oxidizing or reducing atmosphere). The properties of the Am-O system has been analyzed by X diffraction, thermodynamic and ceramography, in the Am 2 O 3 -AmO 2 field. In the third part we study the external exposure risk created by the manufacturing of this target and in the last part the behavior of this target in a fast reactor. 66 refs., 28 figs., 25 tabs., 1 append

AMS detection of actinides at high mass separation

Energy Technology Data Exchange (ETDEWEB)

Steier, Peter; Lachner, Johannes; Priller, Alfred; Winkler, Stephan; Golser, Robin [University of Vienna, Faculty of Physics, Vienna (Austria); Eigl, Rosmarie [Hiroshima University, Earth and Planetary Systems Science, Hiroshima (Japan); Quinto, Francesca [Institut fuer Nukleare Entsorgung, KIT, Eggenstein-Leopoldshafen (Germany); Sakaguchi, Aya [University of Tsukuba, Center for Research in Isotopes and Environmental Dynamics, Tsukuba (Japan)

2015-07-01

AMS is the mass spectrometric method with the highest abundance sensitivity, which is a prerequisite for measurement of the long-lived radioisotope {sup 236}U (t{sub 1/2}=23.4 million years). The most successful application so far is oceanography, since anthropogenic {sup 236}U is present in the world oceans at {sup 236}U:{sup 238}U from 10{sup -11} to 10{sup -8}. We have explored methods to increase the sensitivity and thus to reduce the water volume required to 1 L or less, which significantly reduces the sampling effort. High sensitivity is also necessary to address the expected typical natural isotopic ratios on the order {sup 236}U:{sup 238}U = 10{sup -13}, with potential applications in geology. With a second 90 analyzer magnet and a new Time-of-Flight beam line, VERA is robust against chemical impurities in the background, which e.g. allows measuring Pu isotopes directly in a uranium matrix. This simplifies chemical sample preparation for actinide detection, and may illustrate why AMS reaches lower detection limits than other mass spectrometric methods with nominally higher detection efficiency.

AMS-02 fits dark matter

Science.gov (United States)

Balázs, Csaba; Li, Tong

2016-05-01

In this work we perform a comprehensive statistical analysis of the AMS-02 electron, positron fluxes and the antiproton-to-proton ratio in the context of a simplified dark matter model. We include known, standard astrophysical sources and a dark matter component in the cosmic ray injection spectra. To predict the AMS-02 observables we use propagation parameters extracted from observed fluxes of heavier nuclei and the low energy part of the AMS-02 data. We assume that the dark matter particle is a Majorana fermion coupling to third generation fermions via a spin-0 mediator, and annihilating to multiple channels at once. The simultaneous presence of various annihilation channels provides the dark matter model with additional flexibility, and this enables us to simultaneously fit all cosmic ray spectra using a simple particle physics model and coherent astrophysical assumptions. Our results indicate that AMS-02 observations are not only consistent with the dark matter hypothesis within the uncertainties, but adding a dark matter contribution improves the fit to the data. Assuming, however, that dark matter is solely responsible for this improvement of the fit, it is difficult to evade the latest CMB limits in this model.

AMS-02 fits dark matter

Energy Technology Data Exchange (ETDEWEB)

Balázs, Csaba; Li, Tong [ARC Centre of Excellence for Particle Physics at the Tera-scale,School of Physics and Astronomy, Monash University, Melbourne, Victoria 3800 (Australia)

2016-05-05

In this work we perform a comprehensive statistical analysis of the AMS-02 electron, positron fluxes and the antiproton-to-proton ratio in the context of a simplified dark matter model. We include known, standard astrophysical sources and a dark matter component in the cosmic ray injection spectra. To predict the AMS-02 observables we use propagation parameters extracted from observed fluxes of heavier nuclei and the low energy part of the AMS-02 data. We assume that the dark matter particle is a Majorana fermion coupling to third generation fermions via a spin-0 mediator, and annihilating to multiple channels at once. The simultaneous presence of various annihilation channels provides the dark matter model with additional flexibility, and this enables us to simultaneously fit all cosmic ray spectra using a simple particle physics model and coherent astrophysical assumptions. Our results indicate that AMS-02 observations are not only consistent with the dark matter hypothesis within the uncertainties, but adding a dark matter contribution improves the fit to the data. Assuming, however, that dark matter is solely responsible for this improvement of the fit, it is difficult to evade the latest CMB limits in this model.

AMS at the National Institute of Nuclear Physics and Engineering in Bucharest

International Nuclear Information System (INIS)

Stan-Sion, C.; Ivascu, M.; Plostinaru, D.; Catana, D.; Marinescu, L.; Radulescu, M.; Nolte, E.

2000-01-01

A new beam line and injector deck for AMS measurements have been built at the 8 MV tandem accelerator of the National Institute of Nuclear Physics and Engineering, Bucharest, Romania. The main components on the low-energy side are a high-current cesium sputter source, a 90 deg. injection magnet and a pre-acceleration stage. At the high-energy side the beam line is achromatic, consisting of two 90 deg. analysing magnets with mass energy product 120 MeV amu and a gas-filled ionization chamber. The system will be complete with a Wien filter and a multi-anode gas detector with time-of-flight discrimination. Presently, the AMS facility is undergoing tests and routine measurements are expected to start soon

AMS at the National Institute of Nuclear Physics and Engineering in Bucharest

Energy Technology Data Exchange (ETDEWEB)

Stan-Sion, C. E-mail: stansion@ifin.nipne.ro; Ivascu, M.; Plostinaru, D.; Catana, D.; Marinescu, L.; Radulescu, M.; Nolte, E

2000-10-01

A new beam line and injector deck for AMS measurements have been built at the 8 MV tandem accelerator of the National Institute of Nuclear Physics and Engineering, Bucharest, Romania. The main components on the low-energy side are a high-current cesium sputter source, a 90 deg. injection magnet and a pre-acceleration stage. At the high-energy side the beam line is achromatic, consisting of two 90 deg. analysing magnets with mass energy product 120 MeV amu and a gas-filled ionization chamber. The system will be complete with a Wien filter and a multi-anode gas detector with time-of-flight discrimination. Presently, the AMS facility is undergoing tests and routine measurements are expected to start soon.

Influence of organic fertilization on the sorption mechanisms of {sup 241} Am in tropical soils; A influencia da adubacao organica nos mecanismos de sorcao do {sup 241} Am em solos tropicais

Energy Technology Data Exchange (ETDEWEB)

Pereira, Tatiane Rocha

2009-07-01

In this work the mechanisms involved in the sorption of {sup 241}Am were investigated depending on the physicochemical properties of some Brazilian soils and on alterations promoted by organic amendment. This experimental study was conducted in a controlled area, where pots containing different kinds of soils (histisol, ferralsol and nitisol), with different organic amendment doses (without amendment; 2 kg m{sup -2} and 4 kg m{sup -2}) were artificially contaminated by radioactive solution water, which contained {sup 241}Am. Migration studies, distribution (or partition) coefficient (KJ), bioavailability and organic matter were carried out in these soils, with ar without organic amendment. In order to evaluate the effective bioavailability of radionuclides, radish (Raphanus sativus L.) was cultivated in these pots, and later the concentration of {sup 241}Am in radish's roots was measured. The main results show that {sup 241}Am tends to be strongly attached to organic matter and that organic amendment in tropical soils minimizes the radionuclide studied desorption. Also, distribution (or partition) coefficient values for {sup 241}Am were generated and these values are smaller than those ones determined for soils from temperate zones. Physical and chemical fractioning of organic matter were carried out. (author)

Water and organic nitrate detection in an AMS. Laboratory characterization and application to ambient measurements

Energy Technology Data Exchange (ETDEWEB)

Mensah, Amewu A.

2011-08-12

Atmospheric aerosols were studied by three different means. Laboratory experiments determined the relative ionization efficiency of water (RIE{sub H2O}) in an Aerodyne Aerosol Mass Spectrometers (AMS), simulation chamber experiments gave insight to the reaction products of biogenic volatile organic compounds (BVOC) oxidation products, and the findings were applied to two field campaign measurements at Cabauw, NL, in May 2008 and February 2009. Knowing the liquid water content of aerosol particles is vital for the assessment of their climate forcing potential. A value of 2 for RIE{sub H2O} was determined by studying oxalate salts with different amounts of crystal water. BVOCs contribute much more to the global budget of VOCs than anthropogenic ones but oxidation products in terms of secondary organic aerosol often correlate to anthropogenic tracers such as NO{sub x} from fossil fuel burning. In atmospheric simulation chamber experiments, organic nitrates from BVOC-NO{sub 3} oxidation showed higher vapor pressures than pure organic compounds produced in the same reactions. Organic nitrates comprised up to approx. 41 % of the particulate phase. A specific fragmentation ratio of nitrate (NO{sub 2}{sup +}/NO{sup +}) of 0.1 was found by high resolution AMS analysis differing strongly from the value of 0.4 known for the most abundant ambient NO{sub 3} specie (NH{sub 4}NO{sub 3}). Ambient average particulate mass loadings were 9.72 {mu}g/m{sup 3} dominated by organics (40 %) in 2008 and 5.62 {mu}g/m{sup 3} dominated by nitrate (42 %) in 2009. Data comparison to collocated instruments showed good agreement. Positive Matrix Factorization analysis of the particulate organic fraction distinguished semi and low volatile oxygenated organic aerosol (OOA) as well as hydrocarbon like organic aerosol (HOA) in both campaigns. An additional highly oxygenated OA with a mass spectrum very similar to fulvic acid was found in 2008. The average contribution of organic nitrate to the

América Latina

Directory of Open Access Journals (Sweden)

Marcos Olalla

2007-01-01

Full Text Available Este trabajo analiza el sentido intelectualista de la producción literaria modernista de Latinoamérica. Dicho enfoque es revisado en la obra del escritor argentino Manuel Ugarte (1875-1951 El porvenir de América Latina (1910. Nuestra lectura ofrece algunas líneas para la discriminación de las diversas fuentes ideológicas del intelectualismo en el “americanismo literario”. Consideramos en tal sentido la perspectiva historicista con la que Ugarte describe la composición social de América Latina.

Measurement of magnetic susceptibility on tailings cores report on cores obtained from the Ontario Research Foundation lysimeter experiment

International Nuclear Information System (INIS)

1984-10-01

Bulk susceptibility and induced magnetic remanence results are reported for 40 cores obtained from the uranium tailings lysimeter experiment at the Ontario Research Foundation. Both methods indicate a broad threefold subdivision of the tailings pile. An upper zone is characterized by an enhanced susceptibility level, which is related to enhanced concentration of both magnetite and hematite. Depletion zones, where present, are of limited areal extent and strongly developed. An intermediate zone is characterized by a mixture of large areas of reduced susceptibility that separate smaller regions of slightly enhanced susceptibility. The zones of susceptibility depletion appear to define a dendritic drainage pattern. Locally in this zone magnetite is enhanced and hematite depleted. In the lowermost zone susceptibility levels are reduced over most of the tailings bed. Only in the upper most right hand corner is there any vestige of a positive susceptibility concentration. Both magnetite and hematite are strongly depleted in this lower zone. Visually it is apparent that this lowermost depleted zone correlates to the zones of strongest 'yellowcake' development

The third order nonlinear susceptibility of InAs at infrared region

International Nuclear Information System (INIS)

Musayev, M.A.

2008-01-01

Nonlinear susceptibilities of the third order and coefficient of nonlinear absorption in InAs n-type with a different degree of a doping have been measured. The values of the third order nonlinear susceptibilities have derived from these measurements essentially exceed the values calculated on the basis of model featuring nonlinear susceptibility of electrons, being in conduction-band nonparabolicity. It has been shown that the observable discrepancy has been eliminated, if in calculation a dissipation of energy of electrons has been considered. Growth of efficiency at four-wave mixingin narrow-gap semiconductors has been restricted to nonlinear absorption of interacting waves

A new AMS facility based on a Cockcroft-Walton type 1 MV tandetron at IFIN-HH Magurele, Romania

Science.gov (United States)

Stan-Sion, C.; Enachescu, M.; Ghita, D. G.; Calinescu, C. I.; Petre, A.; Mosu, D. V.; Klein, M.

2014-01-01

A 1 MV AMS machine was recently installed in the National Institute for Physics and Nuclear Engineering IFIN-HH, Bucharest Romania. It is the second AMS facility at IFIN-HH having the goal not only to continue but mainly to enlarge the research area of this highly sensitive analyzing method. The multi-element AMS was developed by HVEE to measure 14C, 10Be, and 26Al, and 129I. The results of an acceptance test are presented and demonstrate that this machine is capable of routine 14C age dating and of measurements of other radioisotopes in terms of accuracy and precision as well as a low background level.

Study of the magnetic susceptibilities of some plutonium derivatives

International Nuclear Information System (INIS)

Raphael, G.

1969-06-01

We present a detailed description of an automatic recording apparatus for magnetic susceptibility measurement of radioactive samples in the temperature range 4 K - 1200 K. We have measured the magnetic susceptibility of various plutonium compounds: - PuO 2 , Pu 2 O 3 , PuO 2-x , - PuS, Pu 2 S 3 , Pu 3 S 4 , (U x Pu 1-x )S - PuN - PuC 1-x (N,O,H,vacancy), Pu 2 C 3 , (U 0.85 Pu 0.15 )C. The curves of susceptibilities versus temperature show many magnetic transitions. The interpretation of these results shows the existence of magnetic moments carried by the 5 f electrons and localized on the metallic sites as well as the great influence of the 'crystal field' in all these compounds. (author) [fr

[Circadian rhythm in susceptibility of mice to the anti-tumor drug carboplatin].

Science.gov (United States)

Lu, X H; Yin, L J

1994-12-01

The platinum-containing compounds has become a major chemical agent in the treatment of cancer. A circadian rhythm in the susceptibility of rodents and human being to cisplatin has been demonstrated, the maximal tolerance being found in the animal's active phase. Carboplatin is a second generation analog. Two studies were performed on mice with carboplatin under 12:12 light dark cycle to study its chronotoxicity and chronoeffectiveness. In study I, single intraperitoneal injection of 192mg/kg (LD50) carboplatin was given to four groups of mice at four different circadian stage. It was found that at 50% the overall mortality of mice, there was a mortality difference of 28% for mice receiving the drug at 9 a.m. to 71% for mice receiving drug at 9 p.m. It demonstrated that carboplatin was better tolerated in the animal's early sleep phase. In study II, S180 tumor-bearing mice were treated with 50mg/kg of carboplatin. The longest mean survival time and the lowest marrow toxicity occurred in the group which received the drug at the beginning of the sleep phase. It showed that the susceptibility of mice to carboplatin is circadian stage dependent. These data clearly demonstrate that, by timing the administration of drugs according to body rhythms, such as the host susceptibility-resistance rhythm to a drug, one can gain a therapeutic advantage over an approach which ignores such rhythms.

Spectroscopic AC susceptibility imaging (sASI) of magnetic nanoparticles

International Nuclear Information System (INIS)

Ficko, Bradley W.; Nadar, Priyanka M.; Diamond, Solomon G.

2015-01-01

This study demonstrates a method for alternating current (AC) susceptibility imaging (ASI) of magnetic nanoparticles (mNPs) using low cost instrumentation. The ASI method uses AC magnetic susceptibility measurements to create tomographic images using an array of drive coils, compensation coils and fluxgate magnetometers. Using a spectroscopic approach in conjunction with ASI, a series of tomographic images can be created for each frequency measurement set and is termed sASI. The advantage of sASI is that mNPs can be simultaneously characterized and imaged in a biological medium. System calibration was performed by fitting the in-phase and out-of-phase susceptibility measurements of an mNP sample with a hydrodynamic diameter of 100 nm to a Brownian relaxation model (R 2 =0.96). Samples of mNPs with core diameters of 10 and 40 nm and a sample of 100 nm hydrodynamic diameter were prepared in 0.5 ml tubes. Three mNP samples were arranged in a randomized array and then scanned using sASI with six frequencies between 425 and 925 Hz. The sASI scans showed the location and quantity of the mNP samples (R 2 =0.97). Biological compatibility of the sASI method was demonstrated by scanning mNPs that were injected into a pork sausage. The mNP response in the biological medium was found to correlate with a calibration sample (R 2 =0.97, p<0.001). These results demonstrate the concept of ASI and advantages of sASI. - Highlights: • Development of an AC susceptibility imaging model. • Comparison of AC susceptibility imaging (ASI) and susceptibility magnitude imaging (SMI). • Demonstration of ASI and spectroscopic ASI (sASI) using three different magnetic nanoparticle types. • SASI scan separation of three different magnetic nanoparticles samples using 5 spectroscopic frequencies. • Demonstration of biological feasibility of sASI

A new compact AMS system at Peking University

International Nuclear Information System (INIS)

Liu Kexin; Ding Xingfang; Fu Dongpo; Pan Yan; Wu Xiaohong; Guo Zhiyu; Zhou Liping

2007-01-01

A compact 14 C AMS system manufactured by the National Electrostatics Corporation has been installed at the Institute of Heavy Ion Physics, Peking University. The system is based on a Model 1.5SDH-1 Pelletron accelerator with a maximum terminal voltage of 0.6 MV. The 14 C measurement accuracy with this system is better than 0.4% and the machine background is lower than 0.03 pMC. The performance of the new system, especially the background and the δ 13 C measurements, is presented. Several important applications are also described briefly

Bats: A new tool for AMS data reduction

International Nuclear Information System (INIS)

Wacker, L.; Christl, M.; Synal, H.-A.

2010-01-01

A data evaluation program was developed at ETH Zurich to meet the requirements of the new compact AMS systems MICADAS and TANDY in addition to the large EN-Tandem accelerator. The program, called 'BATS', is designed to automatically calculate standard and blank corrected results for measured samples. After almost one year of routine operation with the MICADAS C-14 system BATS has proven to be an easy to use data reduction tool that requires minimal user input. Here we present the fundamental principle and the algorithms used in BATS for standard-sized radiocarbon measurements.

The actinide beamline - A new AMS facility at ANTARES

International Nuclear Information System (INIS)

Hotchkis, M.A.C.; Lee, P.J.; Mino, N.

1998-01-01

At the ANTARES accelerator a new beamline has been commissioned, incorporating new magnetic and electrostatic analysers, to optimise the efficiency for Actinides detection by Accelerator Mass Spectrometry. The detection of Actinides, particularly the isotopic ratios of uranium and plutonium, provide unique signatures for nuclear safeguards purposes. We are currently engaged in a project to evaluate the application of AMS to the measurement of Actinides in environmental samples for nuclear safeguards. Measurement of 236 U is of particular interest as a means of tracing the anthropogenic component of uranium. 236 U is expected to be present in natural samples at an extremely low level ( 236 U: 238 U ratio ∼10 -10 ). It has recently been demonstrated that AMS has sufficient sensitivity to detect 236 U at this level. The principal components of the new beamline include: an electrostatic quadrupole, a 12 deg electrostatic deflector, a 90 deg electrostatic analyser, a multi-isotope detection system including ion counters and Faraday cups. The beamline was completed in September 1998 and initial tests have been performed with iodine samples

AMS, a particle spectrometer in space

International Nuclear Information System (INIS)

Buenerd, M.; Ohlsson-Malek, F.; Ren, Z.L.; Santos, D.; Thuillier, T.

1997-01-01

The Alpha Magnetic Spectrometer (AMS) is a detector designed for extraterrestrial study of anti-matter, matter and dark matter. A precursor flight and on the STS-91 flight of the shuttle is planned to take place on May 1998. AMS will be installed on the International Space Station in January 2002 where it will be operated next, for three to five years. The contributions of the ISN to the project on the shuttle (aerogel threshold Cherenkov counter) as well as the steps to build a RICH detector for AMS on the ISSA are explained here below. (authors)

RFQ Reaction Cells for AMS: Developments and Applications

Directory of Open Access Journals (Sweden)

Kieser William E.

2013-12-01

Full Text Available The use of anion-gas interactions in Radiofrequency Quadrupole (RFQ ion guide reaction cells has been shown to be very effective in the elimination of a number of atomic and molecular isobars which have caused difficulties for Accelerator Mass Spectrometry (AMS measurements [1,2]. This presentation begins with a review of the early work leading to the use of ion-gas reactions and continues with a discussion the recent measurements of the efficacy of this technique, some of which involve fluoride molecular anions. However, the transformation of the equipment used for these proof-of-principle measurements into a system suitable for routine analysis has required attention to aspects of the ion beam transport and gas handling subsystems. For example, the cross sections of the ion-gas reactions, involving both the analyte ion as well as the isobar, are critically dependent on the ion energy which has to be reduced from the ion source energy, usually between 20 and 80 keV, to energies typically in the range of several eV, a task complicated by the energy spread and divergence of beams from AMS sputter sources. With simulations using SIMION 8.1 [3] and tests of promising configurations in a laboratory system, principles for the design of the retarder optics have been developed. These are discussed, along with their planned implementation in a next generation analytical system.

Cracking susceptibility of stainless steel subjected to plasma disruption

International Nuclear Information System (INIS)

Madarame, H.

1995-01-01

The similarities and differences in the cracking susceptibility between welding and resolidification after plasma disruption were examined experimentally using a number of primary candidate alloy samples with different chemical compositions. The product of the number density and the average depth of the cracks was measured after simulated disruption, employing a hydrogen ion beam as the heat source, and was compared with the Varestraint test result. An adequate correlation was observed between them, which indicates that the cracking susceptibility during plasma disruption can be well estimated from the welding cracking susceptibility. (orig.)

Report of the working group 'Regulatory requirements on AM - Concept of nuclear and radiation safety during beyond-design-basis accidents'

International Nuclear Information System (INIS)

Bobaly, P.

2001-01-01

The developed working group report contains the following main paragraphs: legal basis and basis for regulatory requirements for on-site and off-site Accident Management (AM), regulatory requirements or recommendations for on-site AM and for emergency preparedness, background information concerning the implementation and review of an AM program as a basis for an AM guideline. Overview about AM/SAM implementation in member countries of the SAMINE project; measure and candidates for high level actions based upon US SAMG; interactions of severe accident research and the regulatory positions, relationship between different components of an accident management programme are also given

Spatial statistical analysis of contamination level of 241Am and 239Pu Thule, North-West Greenland

International Nuclear Information System (INIS)

Strodl Andersen, J.

2011-10-01

A spatial analysis of data on radioactive pollution on land at Thule, North-West Greenland is presented. The data comprises levels of 241 Am and 239,240 Pu on land. Maximum observed level of 241 Am is 2.8x10 5 Bq m -2 . Highest levels were observed near Narsaarsuk. This area was also sampled most intensively. In Groennedal the maximum observed level of 241 Am is 1.9Oe10 4 Bq m -2 . Prediction of the overall amount of 241 Am and 239,240 Pu is based on grid points within the range from the nearest measurement location. The overall amount is therefore highly dependent on the model. Under the optimal spatial model for Narsaarsuk, within the area of prediction, the predicted total amount of 241 Am is 45 GBq and the predicted total amount of 239,240 Pu is 270 GBq. (Author)

AMS: From the ISS to CERN

CERN Multimedia

Jordan Juras

2011-01-01

The week of 16 May 2011 saw the successful launch and installation of the Alpha Magnetic Spectrometer aboard the International Space Station. Only 4 minutes after the installation had been completed, cosmic event data started to be recorded and began its long journey from low Earth orbit to the newly constructed Payload Operations and Control Centre located on CERN's Prévessin site.    The AMS Control Room in the newly constructed Building 946 in CERN’s Prévessin site. Unlike the detectors around the LHC ring, the Alpha Magnetic Spectrometer (AMS) does not have the luxury of a physical connection to data-processing infrastructure. Instead, cosmic events and data on AMS itself must undergo a lengthy journey before they arrive at the Payload and Operations on the Control Centre (POCC - building 946 Prévessin site) of the AMS collaboration. A joint effort between NASA and CERN makes this transmission possible. “The Space Stat...

Effects of tissue susceptibility on brain temperature mapping.

Science.gov (United States)

Maudsley, Andrew A; Goryawala, Mohammed Z; Sheriff, Sulaiman

2017-02-01

A method for mapping of temperature over a large volume of the brain using volumetric proton MR spectroscopic imaging has been implemented and applied to 150 normal subjects. Magnetic susceptibility-induced frequency shifts in gray- and white-matter regions were measured and included as a correction in the temperature mapping calculation. Additional sources of magnetic susceptibility variations of the individual metabolite resonance frequencies were also observed that reflect the cellular-level organization of the brain metabolites, with the most notable differences being attributed to changes of the N-Acetylaspartate resonance frequency that reflect the intra-axonal distribution and orientation of the white-matter tracts with respect to the applied magnetic field. These metabolite-specific susceptibility effects are also shown to change with age. Results indicate no change of apparent brain temperature with age from 18 to 84 years old, with a trend for increased brain temperature throughout the cerebrum in females relative for males on the order of 0.1°C; slightly increased temperatures in the left hemisphere relative to the right; and a lower temperature of 0.3°C in the cerebellum relative to that of cerebral white-matter. This study presents a novel acquisition method for noninvasive measurement of brain temperature that is of potential value for diagnostic purposes and treatment monitoring, while also demonstrating limitations of the measurement due to the confounding effects of tissue susceptibility variations. Copyright © 2016 Elsevier Inc. All rights reserved.

Further improvement for {sup 10}Be measurement on an upgraded compact AMS radiocarbon facility

Energy Technology Data Exchange (ETDEWEB)

Fu, Dongpo; Ding, Xingfang [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, Peking University, Beijing 100871,China (China); Liu, Kexin, E-mail: kxliu@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology and Institute of Heavy Ion Physics, Peking University, Beijing 100871,China (China); Müller, Arnold Milenko; Suter, Martin; Christl, Marcus [Laboratory of Ion Beam Physics, ETH Zürich, 8093 Zürich (Switzerland); Zhou, Liping [Department of Geography, Peking University, Beijing 100871 (China); Synal, Hans-Arno [Laboratory of Ion Beam Physics, ETH Zürich, 8093 Zürich (Switzerland)

2015-10-15

The Peking University 500 kV NEC compact AMS radiocarbon facility (PKU-CAMS) has been modified in order to have additionally the possibility to measure {sup 10}Be. In the preliminary experiment a silicon nitride foil was mounted in front of the electrostatic deflector as passive boron degrader, and the original Si detector for radiocarbon detection was replaced by an ETHZ-designed high-resolution ΔE − E{sub res} gas ionization chamber (GIC) for {sup 10}Be identification. This simple arrangement has yielded an overall {sup 10}Be transmission of 2.2% and a {sup 10}Be/{sup 9}Be background level of 3.5 × 10{sup −14}. To further reduce the background and increase the transmission by re-focusing the {sup 10}Be ions, an additional 90° bending magnet with 350 mm radius was installed after the electrostatic deflector. The silicon detector was shifted slightly relative to its position of original NEC system setup in opposite direction of beam and can be lifted up manually without breaking vacuum when {sup 10}Be measurements are carried out. In this way the system can be easily and fast set up for {sup 10}Be without affecting any parameters for radiocarbon measurement. The gas detector for {sup 10}Be was mounted at the end of the beam line after the additional magnet. The lay-out of the upgraded spectrometer is very compact and does not require more space than the original instrument. Using this compact setup, the overall transmission for {sup 10}Be was doubled to 5–6% and the {sup 10}Be/{sup 9}Be background level was reduced to radios as low as 2.4 × 10{sup −15}.

Measuring transfer of 14C-PCB from maternal diet to milk in a goat model using an accelerator mass spectrometer (AMS)

International Nuclear Information System (INIS)

Janle, E.; Sojka, J.; Jackson, G.S.; Lachcik, P.; Einstien, J.A.; Santerre, C.R.

2007-01-01

Environmental pollutants pose a substantial risk to nursing infants. Many of these toxicants (i.e. PCBs, PBDEs, mercury) are passed from the maternal diet to the nursing infant in breast milk. Determining the toxicokinetics has been difficult to measure due to ethical limitations. Since extremely small amounts of 14 C can be measured using Accelerator Mass Spectrometry (AMS), a goat model was used to establish a minimum oral dose of 14 C-labeled PCB (2,2',4,4',5,5'-hexachlorobiphenyl-UL- 14 C) that could be given to a lactating animal and traced into the milk. An oral dose of 66 nCi/kg body weight (1.84 μg PCB/kg bw) was administered. Plasma and milk samples were collected for 2 months after dosing. The concentration of 14 C label reached a peak value of 1.71 ng/ml PCB equivalents in the milk on day 2 and then declined to about 135 pg/ml PCB equivalents in the milk at 3 weeks. A second goat was administered a smaller dose (22 nCi/kg bw; 616 ng PCB/kg bw). A peak concentration of 485 pg PCB equivalents/ml milk occurred at 3 days and declined to 77.6 pg PCB equivalents/ml milk by 3 weeks. Our results indicated that an even lower dosage of labeled-PCB could be used due to the extreme sensitivity of AMS measurement. Extrapolating from current data it is estimated that the dose could be reduced by a factor of 20 (31 ng PCB/kg bw; 1.1 nCi/kg bw) and still be detectable after 2 months. Thus, the potential exists for developing protocols for studying toxicokinetics in humans using radiologically- and toxicologically-benign doses of labeled environmental toxicants

Field-impressed anisotropy of susceptibility in iron-terbium thin films

International Nuclear Information System (INIS)

Stephenson, A.; Booth, N.A.

1995-01-01

Two thin films of Fe 1-x Tb x where x=0.17 and 0.23 are shown to exhibit the effect of field-impressed anisotropy. After application of a direct field of 80 mT, which gives them an isothermal remanent magnetization (IRM) in their plane, the anisotropy of initial susceptibility differs from that measured after the films have been tumble-demagnetized. By subtracting the susceptibility results of the tumble-demagnetized state from those obtained after the application of the 80 mT direct field, it is shown that the effect of this field is to decrease the susceptibility measured along the former applied field direction and to increase the susceptibility at right angles to this. The effect is almost certainly due to changes in domain alignment. Even though these films contain many domains, the above results are similar to those previously obtained for single-domain γFe 2 O 3 and magnetite particles. The sense of the effect is opposite to that for multi-domain magnetite particles where the susceptibility has been found to increase along the previously applied field direction. ((orig.))

Probing white-matter microstructure with higher-order diffusion tensors and susceptibility tensor MRI

Science.gov (United States)

Liu, Chunlei; Murphy, Nicole E.; Li, Wei

2012-01-01

Diffusion MRI has become an invaluable tool for studying white matter microstructure and brain connectivity. The emergence of quantitative susceptibility mapping and susceptibility tensor imaging (STI) has provided another unique tool for assessing the structure of white matter. In the highly ordered white matter structure, diffusion MRI measures hindered water mobility induced by various tissue and cell membranes, while susceptibility sensitizes to the molecular composition and axonal arrangement. Integrating these two methods may produce new insights into the complex physiology of white matter. In this study, we investigated the relationship between diffusion and magnetic susceptibility in the white matter. Experiments were conducted on phantoms and human brains in vivo. Diffusion properties were quantified with the diffusion tensor model and also with the higher order tensor model based on the cumulant expansion. Frequency shift and susceptibility tensor were measured with quantitative susceptibility mapping and susceptibility tensor imaging. These diffusion and susceptibility quantities were compared and correlated in regions of single fiber bundles and regions of multiple fiber orientations. Relationships were established with similarities and differences identified. It is believed that diffusion MRI and susceptibility MRI provide complementary information of the microstructure of white matter. Together, they allow a more complete assessment of healthy and diseased brains. PMID:23507987

Study of critical current density from ac susceptibility measurements in (La1-xYx)2Ba2CaCu5O2 superconductors

International Nuclear Information System (INIS)

Nayak, P.K.; Ravi, S. . sravi@iitg.ernet.in

2008-01-01

We have prepared a series of compounds (La 1-x Y x ) 2 Ba 2 CaCu 5 O 2 for x = 0 to 0.5 by adding a CaCuO 2 layer to the parent compound La 2 Ba 2 Cu 4 O 2 and by doping Y in place of La. These materials are also prepared by adding 5 wt% of Ag to enhance the intergranular coupling and critical current density. X-ray diffraction measurements show that all the samples are essentially in single phase form and the patterns could be refined using P4/mmm space group in tetragonal cell. The typical lattice parameters are found to be a = b 3.856 A, c = 11.576 A for x = 0.5 sample. Temperature variations of dc electrical resistivity measured on the above samples show that they exhibit superconductivity with T c ranging from 60 to 75 K. Temperature and ac field amplitude variation of ac susceptibility have been measured on the above samples. The field variation of ac susceptibility data has been analyzed by using Bean critical state model. Using both temperature and field variations of ac susceptibility data, the material dependent parameters, such as critical current density as a function of temperature and effective volume fraction grains have been estimated. The Ag doped samples show relatively large critical current density compared to pure samples due to improved intergranular coupling. (author)

Antifungal susceptibilities of Cryptococcus neoformans.

Science.gov (United States)

Archibald, Lennox K; Tuohy, Marion J; Wilson, Deborah A; Nwanyanwu, Okey; Kazembe, Peter N; Tansuphasawadikul, Somsit; Eampokalap, Boonchuay; Chaovavanich, Achara; Reller, L Barth; Jarvis, William R; Hall, Gerri S; Procop, Gary W

2004-01-01

Susceptibility profiles of medically important fungi in less-developed countries remain uncharacterized. We measured the MICs of amphotericin B, 5-flucytosine, fluconazole, itraconazole, and ketoconazole for Cryptococcus neoformans clinical isolates from Thailand, Malawi, and the United States and found no evidence of resistance or MIC profile differences among the countries.

Prisiones e internados: una comparación de los establecimientos penales en América del Norte y América Latina

Directory of Open Access Journals (Sweden)

Christopher Howard Birkbeck

Full Text Available El empleo reciente de términos como "warehouse prison" en Estados Unidos y "campo de concentración" en América Latina parecería indicar que las condiciones de privación de la libertad son distintas en ambas regiones. El análisis presentado aquí explora esas diferencias. Se comparan los establecimientos penales en América del Norte y América Latina a través de seis dimensiones relacionadas entre sí: la organización interna de los espacios, la vigilancia, el aislamiento, la supervisión, el control administrativo y la formalización de los procedimientos. En América del Norte, el control es asiduo (persistente, intrusivo y casi permanente; en América Latina, el control es somero (esporádico, indiferente y superficial. Si en América del Norte se habla de prisiones y encarcelamiento, en América Latina parece mejor hablar de internados judiciales e internación.

Magnetic and structural properties of an octanuclear Cu(II) S=1/2 mesoscopic ring: Susceptibility and NMR measurements

International Nuclear Information System (INIS)

Lascialfari, A.; Jang, Z. H.; Borsa, F.; Gatteschi, D.; Cornia, A.; Rovai, D.; Caneschi, A.; Carretta, P.

2000-01-01

Magnetic susceptibility, 1 H NMR and 63 Cu NMR-NQR experiments on two slightly different species of the molecular S=1/2 antiferromagnetic (AF) ring Cu8, [Cu 8 (dmpz) 8 (OH) 8 ]·2C 5 H 5 N (Cu8P) and [Cu 8 (dmpz) 8 (OH) 8 ]·2C 5 H 5 NO 2 (Cu8N), are presented. The magnetic energy levels are calculated exactly for an isotropic Heisenberg model Hamiltonian in zero magnetic field. From the magnetic susceptibility measurements we estimate the AF exchange coupling constant J∼1000 K and the resulting gap Δ∼500 K between the S T =0 ground state and the S T =1 first excited state. The 63,65 Cu NQR spectra indicate the presence of four crystallographically inequivalent copper nuclei in each ring. From the combination of the 63 Cu NQR spectra and of the 63 Cu NMR spectra at high magnetic field, we estimate the quadrupole coupling constant v Q of each site and the average asymmetry parameter η of the electric-field gradient tensor. The nuclear spin-lattice relaxation rate (NSLR) decreases exponentially on decreasing temperature for all nuclei investigated. The gap parameter extracted from 63 Cu NQR-NSLR is the same as for the susceptibility while a smaller value is obtained from the 63 Cu NMR-NSLR in an external magnetic field of 8.2 T. (c) 2000 The American Physical Society

Influence of organic fertilization on the sorption mechanisms of {sup 241} Am in tropical soils; A influencia da adubacao organica nos mecanismos de sorcao do {sup 241} Am em solos tropicais

Energy Technology Data Exchange (ETDEWEB)

Pereira, Tatiane Rocha

2009-07-01

In this work the mechanisms involved in the sorption of {sup 241}Am were investigated depending on the physicochemical properties of some Brazilian soils and on alterations promoted by organic amendment. This experimental study was conducted in a controlled area, where pots containing different kinds of soils (histisol, ferralsol and nitisol), with different organic amendment doses (without amendment; 2 kg m{sup -2} and 4 kg m{sup -2}) were artificially contaminated by radioactive solution water, which contained {sup 241}Am. Migration studies, distribution (or partition) coefficient (KJ), bioavailability and organic matter were carried out in these soils, with ar without organic amendment. In order to evaluate the effective bioavailability of radionuclides, radish (Raphanus sativus L.) was cultivated in these pots, and later the concentration of {sup 241}Am in radish's roots was measured. The main results show that {sup 241}Am tends to be strongly attached to organic matter and that organic amendment in tropical soils minimizes the radionuclide studied desorption. Also, distribution (or partition) coefficient values for {sup 241}Am were generated and these values are smaller than those ones determined for soils from temperate zones. Physical and chemical fractioning of organic matter were carried out. (author)

Distribution and Excretion of Am-241 in Rats

International Nuclear Information System (INIS)

Alatas, Z; Nurhayati, S; Rahardjo, T

1996-01-01

Determination of the activity content of Am-241 administered oral y in several organs and tissues of white rats including the excretion had been carried out. The observation of Am-241 activity was carried out through surgery and for the excretion of the radionuclide by collecting urine and faces. The surgeries were conducted on the 0 (6 hours), 1, 2, 3, 4, 5, 15 and 30th day post administration of 2.965 kBq Am-241, whereas the urine and faces collections were done every other day for 30 days using metabolism cage. The result indicated that the distribution of Am-241 which found in all tested organs/tissues with various fraction is considered as the initial distribution of Am-241 in rats. The content of americium in gastrointestinal tract and lung is relatively high within the first week post contamination. And, americium activities in other organs/tissues are various with time. The excretion of Am-241 is higher via feces than that of urin, i.e up to 20% in 30 days

Chemical thermodynamic representation of (U, Pu, Am)O2-x

International Nuclear Information System (INIS)

Osaka, Masahiko; Namekawa, Takashi; Kurosaki, Ken; Yamanaka, Shinsuke

2005-01-01

The oxygen potential isotherms of (U, Pu, Am)O 2-x were represented by a chemical thermodynamic model proposed by Lindemer et al. It was assumed in the present model that (U, Pu, Am)O 2-x consisted of the chemical species [UO 2 ], [PuO 2 ], [Pu 4/3 O 2 ], [AmO 2 ] and [Am 5/4 O 2 ] in a pseudo-quaternary system by treating the reduction rates of Pu and Am as identical; furthermore an interaction between [Am 5/4 O 2 ] and [UO 2 ] was introduced. The agreement between analytical and experimental isotherms was good, but the analytical values slightly overestimated the experimental values especially in the case of lower Am content. Adding an interaction between [Am 5/4 O 2 ] and [PuO 2 ] to the model resulted in a better representation

Influence of organic fertilization on the sorption mechanisms of 241 Am in tropical soils

International Nuclear Information System (INIS)

Pereira, Tatiane Rocha

2009-01-01

In this work the mechanisms involved in the sorption of 241 Am were investigated depending on the physicochemical properties of some Brazilian soils and on alterations promoted by organic amendment. This experimental study was conducted in a controlled area, where pots containing different kinds of soils (histisol, ferralsol and nitisol), with different organic amendment doses (without amendment; 2 kg m -2 and 4 kg m -2 ) were artificially contaminated by radioactive solution water, which contained 241 Am. Migration studies, distribution (or partition) coefficient (KJ), bioavailability and organic matter were carried out in these soils, with ar without organic amendment. In order to evaluate the effective bioavailability of radionuclides, radish (Raphanus sativus L.) was cultivated in these pots, and later the concentration of 241 Am in radish's roots was measured. The main results show that 241 Am tends to be strongly attached to organic matter and that organic amendment in tropical soils minimizes the radionuclide studied desorption. Also, distribution (or partition) coefficient values for 241 Am were generated and these values are smaller than those ones determined for soils from temperate zones. Physical and chemical fractioning of organic matter were carried out. (author)

The role of {sup 129} I in the environment and its measurement at the ANTARES AMS center

Energy Technology Data Exchange (ETDEWEB)

Fink, D.; Hotchkis, M.; Lawson, E.M.; Jacobsen, G.E. [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

1996-12-31

Anthropogenic production of several radionuclides during the nuclear era has resulted in a dramatic enhancement in their ambient concentrations relative to cosmogenic values for geophysical systems which are in exchange with the atmosphere and oceans. These environmental pulses have been archived in sediments and polar ice caps where for example profiles of {sup 90}Sr and {sup 135}Cs have been measured to establish global transport rates and deposition budgets for bomb-test products. {sup 129}I, half-life 16 Ma, is another nuclear fission product that is and has been periodically released into the atmosphere, but unlike the shorter lived {sup 90}Sr and {sup 135}Cs, had not found widespread utilization because previous detection via neutron activation analysis ({sup 129}I (2n,{gamma}){sup 131}I) was cumbersome and lacked the required sensitivity. AMS has resolved this problem for {sup 129}I measurements by reducing the required sample size, measurement time and atom-counting sensitivity to as little as 10{sup 6} atoms that enable {sup 129}I/{sup 127}I isotopic ratios as low as 2x10-{sup 14} to be measured on milligram samples within an hour. As a result of this new detection capability, an ever-growing interest and awareness in the application of {sup 129}I as an environmental tracer, radiometric dating tool and monitor of operations of the nuclear industry has been generated. 7 refs.

The role of {sup 129} I in the environment and its measurement at the ANTARES AMS center

Energy Technology Data Exchange (ETDEWEB)

Fink, D; Hotchkis, M; Lawson, E M; Jacobsen, G E [Australian Nuclear Science and Technology Organisation, Lucas Heights, NSW (Australia)

1997-12-31

Anthropogenic production of several radionuclides during the nuclear era has resulted in a dramatic enhancement in their ambient concentrations relative to cosmogenic values for geophysical systems which are in exchange with the atmosphere and oceans. These environmental pulses have been archived in sediments and polar ice caps where for example profiles of {sup 90}Sr and {sup 135}Cs have been measured to establish global transport rates and deposition budgets for bomb-test products. {sup 129}I, half-life 16 Ma, is another nuclear fission product that is and has been periodically released into the atmosphere, but unlike the shorter lived {sup 90}Sr and {sup 135}Cs, had not found widespread utilization because previous detection via neutron activation analysis ({sup 129}I (2n,{gamma}){sup 131}I) was cumbersome and lacked the required sensitivity. AMS has resolved this problem for {sup 129}I measurements by reducing the required sample size, measurement time and atom-counting sensitivity to as little as 10{sup 6} atoms that enable {sup 129}I/{sup 127}I isotopic ratios as low as 2x10-{sup 14} to be measured on milligram samples within an hour. As a result of this new detection capability, an ever-growing interest and awareness in the application of {sup 129}I as an environmental tracer, radiometric dating tool and monitor of operations of the nuclear industry has been generated. 7 refs.

Status report on sample preparation facilities for 14C analysis at the new CologneAMS center

International Nuclear Information System (INIS)

Rethemeyer, J.; Fülöp, R.-H.; Höfle, S.; Wacker, L.; Heinze, S.; Hajdas, I.; Patt, U.; König, S.; Stapper, B.; Dewald, A.

2013-01-01

The new AMS facility at University of Cologne (CologneAMS), Germany, was established in 2010 with the delivery of the HVE 6 MV Tandetron AMS, which will be used for 14 C, 26 Al, 36 Cl, 41 Ca, 129 I, 239 U and 244 Pu analyses. Parallel to the AMS installation the radiocarbon group has started to set up and test sample preparation methods and instruments for different materials. We present first results of reference and standard materials that have been processed and graphitized in our lab and measured at the ETH and CologneAMS facilities. The graphitization blank and its influence on small samples sizes processed with an automated graphitization system have been determined. Work on isolation of individual organic compounds with a preparative gas chromatography system has been started. The focus of our future work will be on reducing process blank levels and sample sizes as well as on the application of compound-specific radiocarbon analyses in (paleo-) environmental research.

Genomic and functional features of the biosurfactant producing Bacillus sp. AM13.

Science.gov (United States)

Shaligram, Shraddha; Kumbhare, Shreyas V; Dhotre, Dhiraj P; Muddeshwar, Manohar G; Kapley, Atya; Joseph, Neetha; Purohit, Hemant P; Shouche, Yogesh S; Pawar, Shrikant P

2016-09-01

Genomic studies provide deeper insights into secondary metabolites produced by diverse bacterial communities, residing in various environmental niches. This study aims to understand the potential of a biosurfactant producing Bacillus sp. AM13, isolated from soil. An integrated approach of genomic and chemical analysis was employed to characterize the antibacterial lipopeptide produced by the strain AM13. Genome analysis revealed that strain AM13 harbors a nonribosomal peptide synthetase (NRPS) cluster; highly similar with known biosynthetic gene clusters from surfactin family: lichenysin (85 %) and surfactin (78 %). These findings were substantiated with supplementary experiments of oil displacement assay and surface tension measurements, confirming the biosurfactant production. Further investigation using LCMS approach exhibited similarity of the biomolecule with biosurfactants of the surfactin family. Our consolidated effort of functional genomics provided chemical as well as genetic leads for understanding the biochemical characteristics of the bioactive compound.

Mass spectrometic isotope dilution analysis of Am and Cm in spent fuels

International Nuclear Information System (INIS)

Wantschik, M.; Koch, L.; Commission of the European Communities, Karlsruhe; Ganser, B.

1983-01-01

Spent nuclear fuels contain Am and Cm in the 10 ppb to 100 ppm range. Because of this low abundance and the necessity of handling small samples of the highly toxic fuel material only a mass-spectrometric isotope dilution analysis can give sufficiently accurate results. Since suitable spikes and/or standards have been lacking, this method has not been applied. Using known masses (+- 0.1%) of Am-241 and Cm-244 metal, Am-243 and Cm-248 spikes were calibrated to an accuracy of better than 0.2%. The standards were reanalysed by chemical titration and several radiometric techniques. The chemical conditioning is based on ionexchange chromatography with alpha-hydroxyisobutyric acid. A sample size of 10 -7 g is sufficient. For the mass-spectrometric measurement 10 -9 g of the elements are required. The accuracy for the determination of the main isotope is 0.5%. (orig./BRB)

Paleomagnetism and Anisotropy of Magnetic Susceptibility study of the Miocene Jack Springs Tuff (Nevada, USA)

Science.gov (United States)

Shields, S.; Petronis, M. S.; Pluhar, C. J.; Gordon, L.

2014-12-01

The mid-Miocene Jack Springs Tuff (JST) outcrops across the western Mina Deflection accommodation zone, west-central Nevada and into eastern California. Previously, the source location for the JST was unknown, yet recent studies northwest of Mono Lake, CA have identified a relatively un-rotated structural block in which to reference the paleomagnetic data. Although new studies have indicated that this block may be rotated up to 13º, we argue that the probable source area is located near the Bodie Hills, CA. At this site, the paleomagnetic reference direction is D = 353°, I = 43°, α95 = 7.7° (Carlson et al, 2013). Based on these data, the JST can be used to measure absolute vertical-axis rotation as well as enable reconstruction of the paleo-topography using the corrected anisotropy of magnetic susceptibility (AMS) data. A total of 19 sites were sampled to constrain Cenozoic to recent vertical axis rotation within the region and AMS experiments were conducted to determine the flow direction of the JST. Curie point estimates indicate that the JST ranges in titanium concentration from 0.042 to 1.10, indicating a low to moderate titanomagnetite phase (Akimoto, 1962). Demagnetization experiments reveal mean destructive fields of the NRM ranging between 15mT and 40mT suggesting that both multi-domain to pseudo-single domain grains are the dominant ferromagnetic phases that carry the remanence and AMS fabric. Preliminary paleomagnetic data yield stable single component demagnetization behavior for most sites that, after structural correction, indicate clockwise vertical axis rotation ranging from +20°± 10° to +60°± 11° between multiple fault blocks. The uncorrected AMS data yield oblate magnetic fabrics that can be used to infer the transport direction, source region, and paleovalley geometry of the JST. These data are tentatively interpreted to indicate west to east transport of the JST across the Mono Basin region into the Mina Deflection that was erupted and

The magnetic susceptibility of soils in Krakow, southern Poland

Science.gov (United States)

Wojas, Anna

2017-06-01

Studies into the magnetic susceptibility have been used to assess the soils contamination in the Krakow area. The results of topsoil (over a 2 × 2 km grid), subsoil (37 shallow holes) and soil samples (112) measurements were presented as maps of soil magnetic susceptibility (both volume and mass) illustrating the distribution of parameters in topsoil horizon (0-10 cm) and differential magnetic susceptibility maps between topsoil horizon and subsoil (40-60 cm). All evidence leads to the finding that the highest values of magnetic susceptibility of soil are found exclusively in industrial areas. Taking into consideration the type of land use, the high median value (89.8 × 10-8 m3kg-1) was obtained for samples of cultivated soils and is likely to be connected with occurrence of fertile soil (chernozem). Moreover, enrichment of soils with Pb and Zn accompanies magnetic susceptibility anomalies in the vicinity of the high roads and in the steelworks area, respectively.

Bats: A new tool for AMS data reduction

Energy Technology Data Exchange (ETDEWEB)

Wacker, L., E-mail: Wacker@phys.ethz.c [Ion Beam Physics, ETH Zurich (Switzerland); Christl, M.; Synal, H.-A. [Ion Beam Physics, ETH Zurich (Switzerland)

2010-04-15

A data evaluation program was developed at ETH Zurich to meet the requirements of the new compact AMS systems MICADAS and TANDY in addition to the large EN-Tandem accelerator. The program, called 'BATS', is designed to automatically calculate standard and blank corrected results for measured samples. After almost one year of routine operation with the MICADAS C-14 system BATS has proven to be an easy to use data reduction tool that requires minimal user input. Here we present the fundamental principle and the algorithms used in BATS for standard-sized radiocarbon measurements.

A small and compact AMS facility for tritium depth profiling

Indian Academy of Sciences (India)

Depth profiling measurements of tritium in carbon samples have been performed during the past seven years at the AMS facility installed at the Rossendorf 3 MV Tandetron. The samples have been cut from the inner walls of the fusion experiments ASDEX-upgrade/Garching and JET/Culham. The tritium content of the ...

Activation measurements for thermal neutrons. Part F. 36Cl measurements in Japan

International Nuclear Information System (INIS)

Nagashima, Yasuo; Seki, Riki; Matsuhiro, Takeshi; Takahashi, Tsutomu; Sasa, Kimikazu; Usui, Toshihide; Sueki, Keisuke

2005-01-01

The development of the accelerator mass spectrometry (AMS) system at the Tandem Accelerator Center of the University of Tsukuba was started in 1995, using the university's own molecular pilot beam technique. Presently, it is the only facility in Japan used to measure 36 Cl (Nagashima et al. 2000). The sensitivity of the 36 Cl AMS system is around 10 -14 36 Cl/Cl atom ratio, which is enough to measure the natural level of the 36 Cl/Cl ratio. The system is characterized by long-term stability, enabling high-quality, continuous measurements over many hours. Our AMS system was used to measure 36 Cl produced in soil by neutrons released into the environment at the time of the JCO criticality accident in Tokai-mura in 1999 (Seki et al. 2003). At the beginning of 2001, our group joined the collaborative efforts to investigate and clarify the discrepancy observed between measurements and calculations of neutron activities induced by the atomic bombings in Hiroshima and Nagasaki. Using our AMS system, 36 Cl was measured in granite samples from Hiroshima exposed to atomic-bomb neutrons and in distant, unexposed samples. (author)

Status of recent utilization of JAEA AMS MUTSU and the revision of the charge

International Nuclear Information System (INIS)

Yamamoto, Nobuo; Kinoshita, Naoki; Kabuto, Shoji; Tanaka, Takayuki

2010-01-01

Tandetron Accelerator Mass Spectrometer in the Japan Atomic Energy Agency Mutsu office (JAEA AMS Mutsu: High Voltage Engineering Europa product, Model 4130-AMS) consists of 3MV tandem type accelerator and the 2 beam lines for measurement of isotope ratio for carbon and iodine. Steady operation of carbon beam line was started in December, 1999 and that of iodine beam line was started in May, 2003. This facility was initially used for studies on transport processes of radionuclides in marine environment. From the fiscal year 2006, this facility became a shared facility to provide data for various projects at JAEA and others. This paper describes the status of recent utilization of JAEA AMS MUTSU, and the revision of the charge from fiscal year 2010. (author)

Assessing MRI susceptibility artefact through an indicator of image distortion

Directory of Open Access Journals (Sweden)

Illanes Alfredo

2016-09-01

Full Text Available Susceptibility artefacts in magnetic resonance imaging (MRI caused by medical devices can result in a severe degradation of the MR image quality. The quantification of susceptibility artefacts is regulated by the ASTM standard which defines a manual method to assess the size of an artefact. This means that the estimated artefact size can be user dependent. To cope with this problem, we propose an algorithm to automatically quantify the size of such susceptibility artefacts. The algorithm is based on the analysis of a 3D surface generated from the 2D MR images. The results obtained by the automatic algorithm were compared to the manual measurements performed by study participants. The results show that the automatic and manual measurements follow the same trend. The clear advantage of the automated algorithm is the absence of the inter- and intra-observer variability. In addition, the algorithm also detects the slice containing the largest artefact which was not the case for the manual measurements.

Prediction Equations Overestimate the Energy Requirements More for Obesity-Susceptible Individuals.

Science.gov (United States)

McLay-Cooke, Rebecca T; Gray, Andrew R; Jones, Lynnette M; Taylor, Rachael W; Skidmore, Paula M L; Brown, Rachel C

2017-09-13

Predictive equations to estimate resting metabolic rate (RMR) are often used in dietary counseling and by online apps to set energy intake goals for weight loss. It is critical to know whether such equations are appropriate for those susceptible to obesity. We measured RMR by indirect calorimetry after an overnight fast in 26 obesity susceptible (OSI) and 30 obesity resistant (ORI) individuals, identified using a simple 6-item screening tool. Predicted RMR was calculated using the FAO/WHO/UNU (Food and Agricultural Organisation/World Health Organisation/United Nations University), Oxford and Miflin-St Jeor equations. Absolute measured RMR did not differ significantly between OSI versus ORI (6339 vs. 5893 kJ·d -1 , p = 0.313). All three prediction equations over-estimated RMR for both OSI and ORI when measured RMR was ≤5000 kJ·d -1 . For measured RMR ≤7000 kJ·d -1 there was statistically significant evidence that the equations overestimate RMR to a greater extent for those classified as obesity susceptible with biases ranging between around 10% to nearly 30% depending on the equation. The use of prediction equations may overestimate RMR and energy requirements particularly in those who self-identify as being susceptible to obesity, which has implications for effective weight management.

Sorption of 241Am by Aspergillus niger spore and hyphae

International Nuclear Information System (INIS)

Yuanyou Yang; Ning Liu; Jiali Liao; Jiannan Jin; Shunzhong Luo; Taiming Zhang; Pengji Zhao

2004-01-01

Biosorption of 241 Am by a fungus A. niger, including the spore and hyphae, was investigated. The preliminary results showed that the adsorption of 241 Am by the microorganism was efficient. More than 96% of the total 241 Am could be removed from 241 Am solutions of 5.6-111 MBq/l (C 0 ) by spore and hyphae of A. niger, with adsorbed 241 Am metal (Q) of 7.2-142.4 MBq/g biomass, and 5.2-106.5 MBq/g, respectively. The biosorption equilibrium was achieved within 1 hour and the optimum pH range was pH 1-3. No obvious effects on 241 Am adsorption by the fungus were observed at 10-45 deg C, or in solutions containing Au 3+ or Ag + , even 2000 times above the 241 Am concentration. The 241 Am biosorption by the fungus obeys the Freundlich adsorption equation. There was no significant difference between the adsorption behavior of A. niger spore and hyphae. (author)

Magnetic susceptibility of Gd/sub 3/Ga/sub 2/

Energy Technology Data Exchange (ETDEWEB)

Hacker, H Jr; Gupta, R M [Duke Univ., Durham, N.C. (USA). Dept. of Electrical Engineering

1976-03-01

The magnetic susceptibility of the intermetallic compound Gd/sub 3/Ga/sub 2/ has been measured by the Faraday method over the range 8 - 300 K. The data indicate antiferromagnetic behavior below 53 K. Above 100 K, the mass susceptibility obeys the Curie-Weiss law, chisub(g)=4.45X10/sup -2//(T+23)emu/gOe. The corresponding effective moment is 8.51 Bohr magnetons.

Multiple sclerosis susceptibility-associated SNPs do not influence disease severity measures in a cohort of Australian MS patients.

Directory of Open Access Journals (Sweden)

Cathy J Jensen

Full Text Available Recent association studies in multiple sclerosis (MS have identified and replicated several single nucleotide polymorphism (SNP susceptibility loci including CLEC16A, IL2RA, IL7R, RPL5, CD58, CD40 and chromosome 12q13-14 in addition to the well established allele HLA-DR15. There is potential that these genetic susceptibility factors could also modulate MS disease severity, as demonstrated previously for the MS risk allele HLA-DR15. We investigated this hypothesis in a cohort of 1006 well characterised MS patients from South-Eastern Australia. We tested the MS-associated SNPs for association with five measures of disease severity incorporating disability, age of onset, cognition and brain atrophy. We observed trends towards association between the RPL5 risk SNP and time between first demyelinating event and relapse, and between the CD40 risk SNP and symbol digit test score. No associations were significant after correction for multiple testing. We found no evidence for the hypothesis that these new MS disease risk-associated SNPs influence disease severity.

Software development for continuous-gas-flow AMS

International Nuclear Information System (INIS)

Reden, K.F. von; Roberts, M.L.; Jenkins, W.J.; Rosenheim, B.E.; McNichol, A.P.; Schneider, R.J.

2008-01-01

The National Ocean Sciences Accelerator Mass Spectrometry (NOSAMS) Facility at Woods Hole Oceanographic Institution is presently completing installation of a novel continuous-flow AMS system. A multi-year development of an AMS microwave gas ion source in collaboration with Atomic Energy Canada Limited (AECL), Chalk River, has preceded this final step of an implementation that is expected to add a new dimension to 14 C AMS. National Instruments, NIM, and CAMAC modules have been programmed with LabVIEW on a Windows XP platform to form the basis for data acquisition. In this paper we discuss possible applications and include simulations of expected data acquisition scenarios like real-time AMS analysis of chromatograms. Particular attention will have to be given to issues of synchronization between rapidly changing input amplitudes and signal processing cycles in hardware and software

Climate Controls AM Fungal Distributions from Global to Local Scales

Science.gov (United States)

Kivlin, S. N.; Hawkes, C.; Muscarella, R.; Treseder, K. K.; Kazenel, M.; Lynn, J.; Rudgers, J.

2016-12-01

Arbuscular mycorrhizal (AM) fungi have key functions in terrestrial biogeochemical processes; thus, determining the relative importance of climate, edaphic factors, and plant community composition on their geographic distributions can improve predictions of their sensitivity to global change. Local adaptation by AM fungi to plant hosts, soil nutrients, and climate suggests that all of these factors may control fungal geographic distributions, but their relative importance is unknown. We created species distribution models for 142 AM fungal taxa at the global scale with data from GenBank. We compared climate variables (BioClim and soil moisture), edaphic variables (phosphorus, carbon, pH, and clay content), and plant variables using model selection on models with (1) all variables, (2) climatic variables only (including soil moisture) and (3) resource-related variables only (all other soil parameters and NPP) using the MaxEnt algorithm evaluated with ENMEval. We also evaluated whether drivers of AM fungal distributions were phylogenetically conserved. To test whether global correlates of AM fungal distributions were reflected at local scales, we then surveyed AM fungi in nine plant hosts along three elevation gradients in the Upper Gunnison Basin, Colorado, USA. At the global scale, the distributions of 55% of AM fungal taxa were affected by both climate and soil resources, whereas 16% were only affected by climate and 29% were only affected by soil resources. Even for AM fungi that were affected by both climate and resources, the effects of climatic variables nearly always outweighed those of resources. Soil moisture and isothermality were the main climatic and NPP and soil carbon the main resource related factors influencing AM fungal distributions. Distributions of closely related AM fungal taxa were similarly affected by climate, but not by resources. Local scale surveys of AM fungi across elevations confirmed that climate was a key driver of AM fungal

Enhancing TRU burning and Am transmutation in Advanced Recycling Reactor

International Nuclear Information System (INIS)

Ikeda, Kazumi; Kochendarfer, Richard A.; Moriwaki, Hiroyuki; Kunishima, Shigeru

2011-01-01

Research highlights: → This ARR is an oxide fueled sodium cooled reactor based on innovative technologies to destruct TRU. → TRU burning core is designed to burn TRU at 28 kg/TW th h, adding moderator pins of B 4 C (Enriched B-11). → Am transmutation core can transmute Am at 34 kg/TW th h, adding uranium free AmN blanket to TRU burning core. → The TRU burning core improves TRU burning by 40-50% than the previous core. → The Am transmutation core can transmute Am effectively, keeping the void reactivity acceptable. - Abstract: This paper presents about conceptual designs of Advanced Recycling Reactor (ARR) focusing on enhancement in transuranics (TRU) burning and americium (Am) transmutation. The design has been conducted in the context of the Global Nuclear Energy Partnership (GNEP) seeking to close nuclear fuel cycle in ways that reduce proliferation risks, reduce the nuclear waste in the US and further improve global energy security. This study strives to enhance the TRU burning and the Am transmutation, assuming the development of related technologies in this study, while the ARR based on mature technologies was designed in the previous study. It has followed that the provided TRU burning core is designed to burn TRU at 28 kg/TW th h, by adding moderator pins of B 4 C (Enriched B-11) and the Am transmutation core will be able to transmute Am at 34 kg/TW th h, by locating Am blanket of AmN around the TRU burning core. It indicates that these concepts improve TRU burning by 40-50% than the previous core and can transmute Am effectively, keeping the void reactivity acceptable.

Comparison Study on Additive Manufacturing (AM) and Powder Metallurgy (PM) AlSi10Mg Alloys

Science.gov (United States)

Chen, B.; Moon, S. K.; Yao, X.; Bi, G.; Shen, J.; Umeda, J.; Kondoh, K.

2018-02-01

The microstructural and mechanical properties of AlSi10Mg alloys fabricated by additive manufacturing (AM) and powder metallurgy (PM) routes were investigated and compared. The microstructures were examined by scanning electron microscopy assisted with electron-dispersive spectroscopy. The crystalline features were studied by x-ray diffraction and electron backscatter diffraction. Room-temperature tensile tests and Vickers hardness measurements were performed to characterize the mechanical properties. It was found that the AM alloy had coarser Al grains but much finer Si precipitates compared with the PM alloy. Consequently, the AM alloy showed more than 100% increment in strength and hardness compared with the PM alloy due to the presence of ultrafine forms of Si, while exhibiting moderate ductility.

Dedekind σ-complete vector lattice of b-AM-compact operators ...

African Journals Online (AJOL)

We give several equivalent conditions characterizing the case when Krb-AM(E,F) is Dedekind σ-complete. Moreover, we describe the case when the space of all regular b-AM-compact operators from E to F is complete under the b-AM-norm. Keywords: Banach lattices, b-AM-compact operator, discrete space ...

Colloquium by prof Samuel TING on AMS results 2016

CERN Multimedia

Brice, Maximilien

2016-01-01

The First Five Years of the Alpha Magnetic Spectrometer on the International Space Station AMS is a multipurpose magnetic spectrometer designed to measure elementary particles and nuclei to the TeV region. In the five years since its installation on the International Space Station, it has collected more than 90 billion cosmic rays. Some of the unexpected results and their possible interpretations will be presented.

Thermal conductivity of (Np0.20Pu0.50Am0.25Cm0.05)O2−x solid solutions

International Nuclear Information System (INIS)

Nishi, Tsuyoshi; Takano, Masahide; Akabori, Mitsuo; Arai, Yasuo

2013-01-01

Highlights: • Thermal conductivity of (Np 0.20 Pu 0.50 Am 0.25 Cm 0.05 )O 2−x was evaluated. • Dependence of thermal conductivity on storage time was clarified. • Results were discussed with the lattice expansion model by self-irradiation. • After annealing at 1423 K in vacuum, thermal conductivity returned. -- Abstract: The authors prepared the sintered sample of (Np 0.20 Pu 0.50 Am 0.25 Cm 0.05 )O 2−x (2 − x = 1.98, 1.96) solid solution and evaluated the dependence of the thermal conductivity on storage time and temperature. The heat capacity of (Np 0.20 Pu 0.50 Am 0.25 Cm 0.05 )O 1.98 was measured between 324 and 1082 K by a drop calorimetry. The thermal diffusivity of (Np 0.20 Pu 0.50 Am 0.25 Cm 0.05 )O 1.98 was measured when the storage time became 48, 216, 720 and 1584 h and that of (Np 0.20 Pu 0.50 Am 0.25 Cm 0.05 )O 1.96 was measured when the storage time became 0,528 and 1386 h. In this study, the latter sample was annealed at 1423 K in vacuum with background pressure of less than 2.0 × 10 −4 Pa just after the measurement on the storage time, 1386 h. The thermal diffusivity of (Np 0.20 Pu 0.50 Am 0.25 Cm 0.05 )O 1.96 just after annealing returned to the values of the storage time, 0 h. This result reveals the thermal recovery behavior by annealing. The thermal conductivity of (Np 0.20 Pu 0.50 Am 0.25 Cm 0.05 )O 2−x was determined from the measured thermal diffusivity, heat capacity and bulk density. The thermal conductivity of (Np 0.20 Pu 0.50 Am 0.25 Cm 0.05 )O 2−x exponentially decreased with increasing storage time. This result suggested that the decrease of the thermal conductivity was attributed to the accumulation of lattice defects caused by self-irradiation

Annotation Method (AM): SE7_AM1 [Metabolonote[Archive

Lifescience Database Archive (English)

Full Text Available base search. Peaks with no hit to these databases are then selected to secondary se...arch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are ma...SE7_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary data

Annotation Method (AM): SE36_AM1 [Metabolonote[Archive

Lifescience Database Archive (English)

Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE36_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

Annotation Method (AM): SE14_AM1 [Metabolonote[Archive

Lifescience Database Archive (English)

Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE14_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

Annotation Method (AM): SE33_AM1 [Metabolonote[Archive

Lifescience Database Archive (English)

Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE33_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

Annotation Method (AM): SE12_AM1 [Metabolonote[Archive

Lifescience Database Archive (English)

Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE12_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

Annotation Method (AM): SE20_AM1 [Metabolonote[Archive

Lifescience Database Archive (English)

Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE20_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

Annotation Method (AM): SE2_AM1 [Metabolonote[Archive

Lifescience Database Archive (English)

Full Text Available base search. Peaks with no hit to these databases are then selected to secondary se...arch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are ma...SE2_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary data

Annotation Method (AM): SE28_AM1 [Metabolonote[Archive

Lifescience Database Archive (English)

Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE28_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

Annotation Method (AM): SE11_AM1 [Metabolonote[Archive

Lifescience Database Archive (English)

Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE11_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

Annotation Method (AM): SE17_AM1 [Metabolonote[Archive

Lifescience Database Archive (English)

Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE17_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

Annotation Method (AM): SE10_AM1 [Metabolonote[Archive

Lifescience Database Archive (English)

Full Text Available abase search. Peaks with no hit to these databases are then selected to secondary s...earch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are m...SE10_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary dat

Annotation Method (AM): SE4_AM1 [Metabolonote[Archive

Lifescience Database Archive (English)

Full Text Available base search. Peaks with no hit to these databases are then selected to secondary se...arch using exactMassDB and Pep1000 databases. After the database search processes, each database hits are ma...SE4_AM1 PowerGet annotation A1 In annotation process, KEGG, KNApSAcK and LipidMAPS are used for primary data