Post-CMOS FinFET integration of bismuth telluride and antimony telluride thin-film-based thermoelectric devices on SoI substrate

KAUST Repository

Aktakka, Ethem Erkan; Ghafouri, Niloufar; Smith, Casey; Peterson, Rebecca Lorenz; Hussain, Muhammad Mustafa; Najafi, Khalil

2013-01-01

This letter reports, for the first time, heterogeneous integration of bismuth telluride (Bi2Te3) and antimony telluride (Sb 2Te3) thin-film-based thermoelectric ffect transistors) via a characterized TE-film coevaporationand shadow-mask patterning

Mercury telluride as a zero-gap semiconductor

International Nuclear Information System (INIS)

Berchenko, N.N.; Pashkovskij, M.V.

1976-01-01

The paper presents a review of main properties of mercury telluride which is a representative of a new class of substances - gapless semiconductors. The causes leading to the appearance of a gapless state in mercury chalcogenides are considered; it is demonstrated that the main role in the formation of the inverse band structure belongs to relativistic corrections. The specific properties of mercury telluride are associated with the zero forbidden band, p-like nature of electron states of the conduction band and its nonparabolicity, resonance states of impurities and anomalies of dielectric permittivity. Conditions of forbidden band appearing in mercury telluride under the effect external factors are analyzed

Californium-252

International Nuclear Information System (INIS)

1975-01-01

This meeting constituted the third phase of a project initiated by the Dosimetry Section of the IAEA in 1973. The first step, early in 1973, consisted of the development of a programme for the loan of Cf-252 sources to the Member States in support of education, training and some limited research. To date, 14 institutions in 13 Member States have participated in this loan programme. In August last year, the Agency published an instructional syllabus and laboratory manual authored by Professors Eric J. Hall and Harald H. Rossi of Columbia University (Californium-252 in Teaching and Research, Technical Reports Series No. 159). The appearance of this publication, including guidance on the design and construction of a storage and use facility, was the second phase of this programme aimed at providing some support to potential users in the fields of radiation biology and dosimetry. The objective of the programme's third phase - the convening of an Educational Seminar - was to provide a forum to bring together participants in the Agency's loan programme and experts in various scientific fields. Specifically, the Seminar consisted of a series of expert presentations in spectrometry, activation and prompt gamma analyses, on-stream analysis, dosimetry, health physics, radiology and radiotherapy. (author)

X-ray-diffraction study of californium metal to 16 GPa

International Nuclear Information System (INIS)

Peterson, J.R.; Benedict, U.; Dufour, C.; Birkel, I.; Haire, R.G.

1983-01-01

The first series of measurements to determine the structural behavior of californium (Cf) metal under pressure has been carried out. The initial dhcp structure transformed sluggishly with increasing pressure to a fcc structure. A bulk modulus of 50(5) GPa was derived for dhcp Cf metal from the relative volume (V/V 0 ) data to 10 GPa

Study of the shielding for spontaneous fission sources of Californium-252

International Nuclear Information System (INIS)

Davila R, I.

1991-06-01

A shielding study is made to attenuate, until maximum permissible levels, the neutrons radiation and photons emitted by spontaneous fission coming from a source of Californium-252. The compound package by a database (Library DLC-23) and the ANISNW code is used, in it version for personal computer. (Author)

Occurency and aqueous processing of tellurides from Sonora (Mexico)

International Nuclear Information System (INIS)

Aguayo, S.; Perez, E.; Ecinas, M.A.

1996-01-01

Tellurium production is limited mainly to that obtained from the treatment of electrolyte muds from copper refineries. however, there are several other sources from which the precious metal tellurides are potentially attractive. This work presents a review of the main localitiesin Sonora (Mexico), where tellurides have been found. In addition, based upon the physical chemistry fundamentals for tellurium and precious metal tellurides, the aqueous extraction and recovery routes are discussed. (Author) 51 refs

Convenient method of simultaneously analyzing aluminum and magnesium in pharmaceutical dosage forms using californium-252 thermal neutron activation

International Nuclear Information System (INIS)

Landolt, R.R.; Hem, S.L.

1983-01-01

A commercial antacid suspension containing aluminum hydroxide and magnesium hydroxide products was used as a model sample to study the use of a californium-252 thermal neutron activation as a method for quantifying aluminum content as well as for the simultaneous assay of aluminum and magnesium. A 3.5-micrograms californium-252 source was used for the activation, and the induced aluminum-28 and magnesium-27 activity was simultaneously measured by sodium iodide crystal gamma-ray spectrometry using dual single-channel analyzers and scalers. The antacid suspension was contained in a chamber designed with the unique capability of serving as the container for counting the induced radioactivity in addition to being the irradiation chamber itself. This pilot study demonstrated that use of more intense californium-252 sources, which are commonly available, would provide a method that is competitive with the ethylenediaminetetraacetic acid titration method in precision and in other aspects as well

About thermo-electric properties of bismuth telluride doped by gadolinium

International Nuclear Information System (INIS)

Akperov, M.M.; Ismailov, Sh.S.; Shukyurova, A.A.

2004-01-01

Results of study of the Gd impurities effect on the bismuth telluride thermo-electric properties are presented. The experiment was carried out within the temperature range T=300-700 K. It is determined, that at temperature increase the energy level is appreciably closing up to bismuth telluride forbidden zone which makes up 0.16-0.24 eV. Such anomalous energy properties of gadolinium in telluride affect on material thermoelectric properties

Tellurium self-diffusion and point defects in lead telluride

International Nuclear Information System (INIS)

Simirskij, Yu.N.; Firsova, L.P.

1982-01-01

Method of radioactive indicators was used to determine factors of tellurium self-diffusion in lead telluride with different deviation of the composition from stoichiometric in the range of enrichment by tellurium. It was found that at 973 K factors of tellurium self-diffusion in lead telluride depend slightly on the vapor pressure of tellurium equilibrium with solid phase

Cadmium Telluride-Titanium Dioxide Nanocomposite for Photodegradation of Organic Substance.

Science.gov (United States)

Ontam, Areeporn; Khaorapapong, Nithima; Ogawa, Makoto

2015-12-01

Cadmium telluride-titanium dioxide nanocomposite was prepared by hydrothermal reaction of sol-gel derived titanium dioxide and organically modified cadmium telluride. The crystallinity of titanium dioxide in the nanocomposite was higher than that of pure titanium dioxide obtained by the reaction under the same temperature and pressure conditions, showing that cadmium telluride induced the crystallization of titanium dioxide. Diffuse reflectance spectrum of the nanocomposite showed the higher absorption efficiency in the UV-visible region due to band-gap excitation of titanium dioxide. The nanocomposite significantly showed the improvement of photocatalytic activity for 4-chlorophenol with UV light.

Synthesis and evaluation of lead telluride/bismuth antimony telluride nanocomposites for thermoelectric applications

Science.gov (United States)

Ganguly, Shreyashi; Zhou, Chen; Morelli, Donald; Sakamoto, Jeffrey; Uher, Ctirad; Brock, Stephanie L.

2011-12-01

Heterogeneous nanocomposites of p-type bismuth antimony telluride (Bi 2- xSb xTe 3) with lead telluride (PbTe) nanoinclusions have been prepared by an incipient wetness impregnation approach. The Seebeck coefficient, electrical resistivity, thermal conductivity and Hall coefficient were measured from 80 to 380 K in order to investigate the influence of PbTe nanoparticles on the thermoelectric performance of nanocomposites. The Seebeck coefficients and electrical resistivities of nanocomposites decrease with increasing PbTe nanoparticle concentration due to an increased hole concentration. The lattice thermal conductivity decreases with the addition of PbTe nanoparticles but the total thermal conductivity increases due to the increased electronic thermal conductivity. We conclude that the presence of nanosized PbTe in the bulk Bi 2- xSb xTe 3 matrix results in a collateral doping effect, which dominates transport properties. This study underscores the need for immiscible systems to achieve the decreased thermal transport properties possible from nanostructuring without compromising the electronic properties.

Atlantic Richfield Hanford Company californium multiplier/delayed neutron counter safety analysis

International Nuclear Information System (INIS)

Zimmer, W.H.

1976-08-01

The Californium Multiplier (CFX) is a subcritical assembly of uranium surrounding 252 Cf spontaneously fissioning neutron sources; its function is to multiply the neutron flux to a level useful for activation analysis. This document summarizes the safety analysis aspects of the CFX, DNC, pneumatic transfer system, and instrumentation and to detail all the aspects of the total facility as a starting point for the ARHCO Safety Analysis Review. Recognized hazards and steps already taken to neutralize them are itemized

Californium oxygen system for 1.50 < O/Cf < 1.72

International Nuclear Information System (INIS)

Turcotte, R.P.; Haire, R.G.

1975-01-01

The californium-oxygen system was studied as a function of temperature, oxygen pressure, and stoichiometry by manometric and x-ray diffraction methods. The results establish rhombohedral Cf 7 O 12 as the stable compound obtained by heating Cf 2 O 3 in air. The isobaric oxidation-reduction cycles Cf 2 O 3 → Cf 7 O 12 → Cf 2 O 3 , observed in constant rate of heating (cooling) experiments, occur with large hysteresis. A close parallel to other fluorite related lanthanide and actinide oxide systems is established. (auth)

Lead telluride with increased mechanical stability for cylindrical thermoelectric generators

International Nuclear Information System (INIS)

Schmitz, Andreas

2013-01-01

The aim of this work is to improve the mechanical stability of lead telluride (PbTe), trying to vary its mechanical properties independently from its thermoelectric properties. Thus the influence of material preparation as well as different dopants on the mechanical and thermoelectric properties of lead telluride is being analysed. When using appropriately set process parameters, milling and sintering of lead telluride increases the material's hardness. With sintering temperatures exceeding 300 C stable material of high relative density can be achieved. Milling lead telluride generates lattice defects leading to a reduction of the material's charge carrier density. These defects can be reduced by increased sintering temperatures. Contamination of the powder due to the milling process leads to bloating during thermal cycling and thus reduced density of the sintered material. In addition to that, evaporation of tellurium at elevated temperatures causes instability of the material's thermoelectric properties. Based on the experimental results obtained in this work, the best thermoelectric and mechanical properties can be obtained by sintering coarse powders at around 400 C. Within this work a concept was developed to vary the mechanical properties of lead telluride via synthesis of PbTe with electrically nondoping elements, which thus may keep the thermoelectric properties unchanged. Therefore, the mechanical and thermoelectric properties of Pb 1-x Ca x Te were investigated. Doping pure PbTe with calcium causes a significant increase of the material's hardness while only slightly decreasing the charge carrier density and thus keeping the thermoelectric properties apart from a slight reduction of the electrical conductivity nearly unchanged. The abovementioned concept is proven using sodium doped lead telluride, as it is used for thermoelectric generators: The additional doping with calcium again increases the material's hardness while its thermoelectric properties

Studies of antimony telluride and copper telluride films electrodeposition from choline chloride containing ionic liquids

Energy Technology Data Exchange (ETDEWEB)

Catrangiu, Adriana-Simona; Sin, Ion [Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, POLITEHNICA University of Bucharest, Calea Grivitei 132, Bucharest (Romania); Prioteasa, Paula [INCDIE ICPE-Advanced Research, Splaiul Unirii 313, Bucharest (Romania); Cotarta, Adina [Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, POLITEHNICA University of Bucharest, Calea Grivitei 132, Bucharest (Romania); Cojocaru, Anca, E-mail: a_cojocaru@chim.upb.ro [Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, POLITEHNICA University of Bucharest, Calea Grivitei 132, Bucharest (Romania); Anicai, Liana [Center of Surface Science and Nanotechnology, University POLITEHNICA of Bucharest, Splaiul Independentei 313, Bucharest (Romania); Visan, Teodor [Department of Inorganic Chemistry, Physical Chemistry and Electrochemistry, POLITEHNICA University of Bucharest, Calea Grivitei 132, Bucharest (Romania)

2016-07-29

Cyclic voltammetry and electrochemical impedance spectroscopy were used to investigate the deposition of antimony telluride or copper telluride from ionic liquid consisting in mixture of choline chloride with oxalic acid. In addition, the cathodic process during copper telluride formation was studied in the mixture of choline chloride with ethylene glycol. The results indicate that the Pt electrode is first covered with a Te layer, and then the more negative polarisation leads to the deposition of Sb{sub x}Te{sub y} or Cu{sub x}Te{sub y} semiconductor compounds. Thin films were deposited on copper and carbon steel at 60–70 °C and were characterised by scanning electron microscopy, energy X-ray dispersive spectroscopy (EDS), and X-ray diffraction (XRD). Their stoichiometry depends on the bath composition and applied potential. EDS and XRD patterns indicate the possible synthesis of stoichiometric Sb{sub 2}Te{sub 3} phase and Cu{sub 2}Te, Cu{sub 5}Te{sub 3}, and Cu{sub 2.8}Te{sub 2} phases, respectively, by controlling the ratio of ion concentrations in ionic liquid electrolytes and deposition potential. - Highlights: • Sb{sub x}Te{sub y} and Cu{sub x}Te{sub y} films electrodeposited from choline-chloride-based ionic liquids. • The stoichiometry of film depends on the bath composition and deposition potential. • Sb{sub 2}Te{sub 3}, Cu{sub 2}Te, Cu{sub 5}Te{sub 3}, Cu{sub 2.8}Te{sub 2} phases were identified in X-ray diffraction patterns.

Electrochemical Deposition of Lanthanum Telluride Thin Films and Nanowires

Science.gov (United States)

Chi, Su (Ike); Farias, Stephen; Cammarata, Robert

2013-03-01

Tellurium alloys are characterized by their high performance thermoelectric properties and recent research has shown nanostructured tellurium alloys display even greater performance than bulk equivalents. Increased thermoelectric efficiency of nanostructured materials have led to significant interests in developing thin film and nanowire structures. Here, we report on the first successful electrodeposition of lanthanum telluride thin films and nanowires. The electrodeposition of lanthanum telluride thin films is performed in ionic liquids at room temperature. The synthesis of nanowires involves electrodepositing lanthanum telluride arrays into anodic aluminum oxide (AAO) nanoporous membranes. These novel procedures can serve as an alternative means of simple, inexpensive and laboratory-environment friendly methods to synthesize nanostructured thermoelectric materials. The thermoelectric properties of thin films and nanowires will be presented to compare to current state-of-the-art thermoelectric materials. The morphologies and chemical compositions of the deposited films and nanowires are characterized using SEM and EDAX analysis.

Properties of Nitrogen-Doped Zinc Telluride Films for Back Contact to Cadmium Telluride Photovoltaics

Science.gov (United States)

Shimpi, Tushar M.; Drayton, Jennifer; Swanson, Drew E.; Sampath, Walajabad S.

2017-08-01

Zinc telluride (ZnTe) films have been deposited onto uncoated glass superstrates by reactive radiofrequency (RF) sputtering with different amounts of nitrogen introduced into the process gas, and the structural and electronic transport properties of the resulting nitrogen-doped ZnTe (ZnTe:N) films characterized. Based on transmission and x-ray diffraction measurements, it was observed that the crystalline quality of the ZnTe:N films decreased with increasing nitrogen in the deposition process. The bulk carrier concentration of the ZnTe:N films determined from Hall-effect measurements showed a slight decrease at 4% nitrogen flow rate. The effect of ZnTe:N films as back contact to cadmium telluride (CdTe) solar cells was also investigated. ZnTe:N films were deposited before or after CdCl2 passivation on CdTe/CdS samples. Small-area devices were characterized for their electronic properties. Glancing-angle x-ray diffraction measurements and energy-dispersive spectroscopy analysis confirmed substantial loss of zinc from the samples where CdCl2 passivation was carried out after ZnTe:N film deposition.

Method of Creating Micro-scale Silver Telluride Grains Covered with Bismuth Nanoparticles

Science.gov (United States)

Kim, Hyun-Jung (Inventor); Choi, Sang Hyouk (Inventor); King, Glen C. (Inventor); Park, Yeonjoon (Inventor); Lee, Kunik (Inventor)

2014-01-01

Provided is a method of enhancing thermoelectric performance by surrounding crystalline semiconductors with nanoparticles by contacting a bismuth telluride material with a silver salt under a substantially inert atmosphere and a temperature approximately near the silver salt decomposition temperature; and recovering a metallic bismuth decorated material comprising silver telluride crystal grains.

Assessment of the neutron component in a neutron-gamma field of a californium-252 source

International Nuclear Information System (INIS)

Tetteh, G.K.

1978-12-01

Experiments have been performed to determine the percentages of the different components in the radiation field of californium-252 which has now some clinical applications. Using Rossi Chambers in conjunction with absorption investigations involving lead and aluminium thimbles, it is observed that the dose rates due to the different components are: neutrons 54%; gammas 30%; betas 16%

Special features of self-compensation of halogen donor action in lead telluride

International Nuclear Information System (INIS)

Kajdanov, V.I.; Nemov, S.A.; Ravich, Yu.I.; Dereza, A.Yu.

1985-01-01

Specific features of self-compensation of halogen donor action in lead telluride are investigasted. Lead telluride samples with chlorine additions (with tellurium excess) and, besides, with bromine- and iodine additions were studied in order to reveal general regularities in alloyind with all halogen donor impurities. Experimental dependences of the difference between the electron and hole concentrations (n-p) in PbTe as a function of an amount of introduced halogen impurities (Ni) are presented for samples with a maximum compensation at 295 K. General features of the n-p=f(Ni) dependence are presented for all halogens. The hypothesis on the kinetic mechanism of increasing the efficiency of self-compensation of halogen donor action in lead telluride is suggested

Measurements of integral cross sections in the californium-252 fission neutron spectrum

International Nuclear Information System (INIS)

Alberts, W.G.; Guenther, E.; Matzke, M.; Rassl, G.

1977-01-01

In a low-scattering arrangement cross sections averaged over the californium-252 spontaneous fission neutron spectrum were measured. The reactions 27 Al(n,α) 46 Ti, 47 Ti, 48 Ti(n,p), 54 Fe, 56 Fe(n,p), 58 Ni(n,p), 64 Zn(n,p), 115 In(n,n') were studied in order to obtain a consistent set of threshold detectors used in fast neutron flux density measurements. Overall uncertainties between 2 and 2.5% could be achieved; corrections due to neutron scattering in source and samples are discussed

Properties of Nanostructure Bismuth Telluride Thin Films Using Thermal Evaporation

Directory of Open Access Journals (Sweden)

Swati Arora

2017-01-01

Full Text Available Bismuth telluride has high thermoelectric performance at room temperature; in present work, various nanostructure thin films of bismuth telluride were fabricated on silicon substrates at room temperature using thermal evaporation method. Tellurium (Te and bismuth (Bi were deposited on silicon substrate in different ratio of thickness. These films were annealed at 50°C and 100°C. After heat treatment, the thin films attained the semiconductor nature. Samples were studied by X-ray diffraction (XRD and scanning electron microscopy (SEM to show granular growth.

Post-CMOS FinFET integration of bismuth telluride and antimony telluride thin-film-based thermoelectric devices on SoI substrate

KAUST Repository

Aktakka, Ethem Erkan

2013-10-01

This letter reports, for the first time, heterogeneous integration of bismuth telluride (Bi2Te3) and antimony telluride (Sb 2Te3) thin-film-based thermoelectric ffect transistors) via a characterized TE-film coevaporationand shadow-mask patterning process using predeposition surface treatment methods for reduced TE-metal contact resistance. As a demonstration vehicle, a 2 × 2 mm2-sized integrated planar thermoelectric generator (TEG) is shown to harvest 0.7 μ W from 21-K temperature gradient. Transistor performance showed no significant change upon post-CMOS TEG integration, indicating, for the first time, the CMOS compatibility of the Bi2Te3 and Sb2Te3 thin films, which could be leveraged for realization of high-performance integrated micro-TE harvesters and coolers. © 2013 IEEE.

Instrumental neutron activation determination of gold in mineral raw materials using a californium neutron source

International Nuclear Information System (INIS)

Shilo, N.A.; Ippolitov, E.G.; Ivanenko, V.V.; Kustov, B.N.; Zheleznov, V.V.; Aristov, G.N.; Kovalenko, V.V.; Kondrat'ev, N.B.

1983-01-01

A facility using a californium neutron source and a method for the neutron activation analysis of gold were developed. The sensitivity of the determination is 0.1 g/t. The causes of random and systematic errors have been studied. It is concluded that in prospection and evaluation of gold ore deposists, the traditional test tube analysis for gold may be replaced with the developed method. (author)

Neutron reflector design with Californium 252 neutron for Boron neutron chapter therapy facility using MCNP5 simulation method

International Nuclear Information System (INIS)

Muhammad Fakhrurreza; Kusminanto; Y Sardjono

2014-01-01

In this research has made a reflector design to provide beams of Neutron for BNCT with Californium-252 radioactive source. This collimator is useful to obtain optimum epithermal neutron flux with the smallest impurity radiation (thermal neutron, fast neutron, and gamma). The design process is done using Monte Carlo N-Particle simulation version 5 (MCNP5) code to calculate the neutron flux tally form. The chosen reflector design is the reflectors which use material such as BeO ceramic with 13 cm thick. Moderator use sulfur material with the slope angle of the cone is 30°. From the calculation result, it is obtained that Reflector with 1 gram Californium-252 source can produce a neutron output thermal which has thermal neutron specification 2.23189 x 10 9 n/s.cm 2 , epithermal neutron 3.51548 x 10 9 n/s.cm 2 , and fast neutron 4.82241 x 10 9 n/s.cm 2 From the result, it needs additional collimator because the BNCT requirement. (author)

Calibration of a Modified Californium Shuffler

International Nuclear Information System (INIS)

Sadowski, E.T.; Armstrong, F.; Oldham, R.; Ceo, R.; Williams, N.

1995-01-01

A californium shuffler originally designed to assay hollow cylindrical pieces of UA1 has been modified to assay solid cylinders. Calibration standards were characterized via chemical analysis of the molten UA1 taken during casting of the standards. The melt samples yielded much more reliable characterization data than drill samples taken from standards after the standards had solidified. By normalizing one well-characterized calibration curve to several standards at different enrichments, a relatively small number of standards was required to develop an enrichment-dependent calibration. The precision of this shuffler is 0.65%, and the typical random and systematic uncertainties are 0.53% and 0.73%, respectively, for a six minute assay of an ingot containing approximately 700 grams of 235 U. This paper will discuss (1) the discrepancies encountered when UA1 standards were characterized via melt samples versus drill samples, (2) a calibration methodology employing a small number of standards, and (3) a comparison of results from a previously unused shuffler with an existing shuffler. A small number of UA1 standards have been characterized using samples from the homogeneous molten state and have yielded enrichment-dependent and enrichment-independent calibration curves on two different shufflers

Dissolution kinetics of lead telluride in alkali solutions of hydrogen peroxide

International Nuclear Information System (INIS)

Danilova, M.G.; Sveshnikova, L.L.; Stavitskaya, T.A.; Repinskij, S.M.

1991-01-01

Dissolution kinetics of lead telluride in alkali solutions of hydrogen peroxide was investigated. Dependences of change of PbTe dissolution rate on concentration of hydrogen peroxide and alkali in the solution were obtained. It is shown that dissolution rate of lead telluride is affected by dissolution rate of lead oxide, representing the product of ReTe dissolution. The obtained regularities can be explained by change of solution structure with increase of KOH concentration and by the state of hydrogen peroxide in the solution

Prompt neutron spectrum of the spontaneous fission of californium-252

International Nuclear Information System (INIS)

Zamyatnin, Yu.S.; Kroshkin, N.I.; Korostylev, V.A.; Nefedov, V.N.; Ryazanov, D.K.; Starostov, B.I.; Semenov, A.F.

1976-01-01

The californium-252 spontaneous fission neutron spectrum was measured in the energy range of 0.01 to 10 MeV by the time-of-flight technique using various neutron detectors. The measurements of 252 Cf neutron spectrum at energies of 0.01 to 5 MeV were performed as a function of fission fragment kinetic energy. The mean neutron spectrum energy in the range of 0.7 to 10 MeV was found from the results of measurements. The irregularity in the 252 Cf neutron spectrum in the neutron energy range of less than 0.7 MeV compared to theoretical values is discussed. The mechanism of 252 Cf neutron emission is also discussed on the basis of neutron yield angle measurements. 12 references

Telluride School, Telluride, Colorado solar-energy-system performance evaluation, February 1982-April 1982

Energy Technology Data Exchange (ETDEWEB)

Welch, K.M.

1982-01-01

The Telluride School solar site is an elementary/junior-senior high school in Colorado with a passive/active hybrid solar energy system designed to supply 40% of the heating load. It is equipped with a 1428 square foot, double glazed Trombe wall, a 1392 square foot greenhouse with collection tube, and an auxiliary oil-fired boiler. Monthly performance data are tabulated for the overall system and for the Trombe wall, greenhouse, and greenhouse storage. System operation is illustrated by graphs of typical Trombe wall insolation and temperatures and typical greenhouse insolation and temperatures. (LEW)

High-temperature thermoelectric behavior of lead telluride

Indian Academy of Sciences (India)

The central problem in thermoelectric material research is the selection of ... temperature range (400–1000 K), and bismuth telluride-based materials .... parent from the results that band non-parabolicity has a significant effect on the .... M P Singh thankfully acknowledges financial assistance from the Council of Scien-.

Safety Analysis Report for Packaging (SARP) of the Oak Ridge National Laboratory TRU Californium Shipping Container

International Nuclear Information System (INIS)

Box, W.D.; Shappert, L.B.; Seagren, R.D.; Klima, B.B.; Jurgensen, M.C.; Hammond, C.R.; Watson, C.D.

1980-01-01

An analytical evaluation of the Oak Ridge National Laboratory TRU Californium Shipping Container was made in order to demonstrate its compliance with the regulations governing off-site shipment of packages that contain radioactive material. The evaluation encompassed five primary categories: structural integrity, thermal resistance, radiation shielding, nuclear criticality safety, and quality assurance. The results of this evaluation demonstrate that the container complies with the applicable regulations

Neutron emission in fission of highly excited californium nuclei (E*=76 MeV)

International Nuclear Information System (INIS)

Blinov, M.V.; Bordyug, V.M.; Kozulin, Eh.M.; Mozhaev, A.N.; Levitovich, M.; Muzychka, Yu.A.; Penionzhkevich, Yu.Eh.; Pustyl'nik, B.I.

1990-01-01

The differential cross sections for neutron production in the fission of highly excited californium nuclei formed in the 238 U+ 12 C (105 MeV) reaction have been measured. From the analysis of the experimental data is follows that the number of pre-fission neutrons substantially exceeds the value obtained in the framework of the standard statistical model. The saddle-to-scission time of the excited nucleus is estimated on the basis of the neutron multiplicity. The dependences of the neutron number and neutron average energies upon the fragment mass are determined

Neutron emission in fission of highly excited californium nuclei (E* = 76 MeV)

International Nuclear Information System (INIS)

Blinov, M.V.; Bordyug, V.M.; Kozulin, E.M.; Levitovich, M.; Mozhaev, A.N.; Muzychka, Yu.A.; Penionzhkevich, Yu.E.; Pustyl'nik, B.I.

1990-01-01

Differential cross sections for neutron production have been measured in fission of excited californium nuclei produced in the reaction 238 U + 12 C (105 MeV). It follows from analysis of the experimental results that the number of neutrons emitted before fission considerably exceeds the number obtained in the framework of the standard statistical model. On the basis of the multiplicity of neutrons they authors have estimated the time of fission of the excited nucleus. The dependence of the number of neutrons and their average energies on the mass of the fragments is determined

Thin-film cadmium telluride photovoltaics: ES and H issues, solutions, and perspectives

International Nuclear Information System (INIS)

Zweibel, K.; Moskowitz, P.; Fthenakis, V.

1998-02-01

Photovoltaics (PV) is a growing business worldwide, with new technologies evolving towards potentially large-volume production. PV use produces no emissions, thus offsetting many potential environmental problems. However, the new PV technologies also bring unfamiliar environment, safety, and health (ES and H) challenges that require innovative solutions. This is a summary of the issues, solutions, and perspectives associated with the use of cadmium in one of the new and important PV technologies: thin-film, cadmium telluride (CdTe) PV, which is being developed and commercialized by several companies including Solar Cells Inc. (Toledo, Ohio), BP Solar (Fairfield, California), and Matsushita (Japan). The principal ES and H issue for thin-film cadmium telluride PV is the potential introduction of cadmium--a toxic heavy metal--into the air or water. The amount of cadmium in thin-film PV, however, is quite small--one nickel cadmium flashlight battery has about as much cadmium (7 g) as a square meter of PV module using current technology--and a typical cordless power tool will have 5--10 batteries. CdTe modules are also very well sealed, limiting the chance of release. Nonetheless, minimizing the amount of cadmium in cadmium telluride modules and preventing the introduction of that cadmium into the environment is a top priority for National Renewable Energy Laboratory researchers and cadmium telluride PV manufacturers

A californium-252 source for radiobiological studies at Hiroshima University

International Nuclear Information System (INIS)

Kato, Kazuo; Takeoka, Seiji; Kuroda, Tokue; Tsujimura, Tomotaka; Kawami, Masaharu; Hoshi, Masaharu; Sawada, Shozo

1987-01-01

A 1.93 Ci (3.6 mg) californium-252 source was installed in the radiation facility of the Research Institute for Nuclear Medicine and Biology, Hiroshima University. This source produces fission neutrons (8.7 x 10 9 n/s at the time of its installation), which are similar to neutron spectrum of the atomic bombs. It is useful for studying biological effects of fission neutrons and neutron dosimetry. An apparatus was dosigned to accomodate this source and to apply it to such studies. It has resulted in profitable fission neutron exposures, while suppressing scattered neutrons and secondary gamma rays. This apparatus incorporates many safety systems, including one which interlocks with all of doors and an elevator serving the exposure room, so as to prevent accidents involving users. (author)

Californium production at the transuranium processing plant

International Nuclear Information System (INIS)

King, L.J.

1976-01-01

The Transuranium Processing Plant (TRU) at ORNL, which is the production, storage, and distribution center for the ERDA heavy element research program, is described. About 0.5 percent of 252 Cf is currently being produced. TRU is a hot-cell, chemical processing facility of advanced design. New concepts have been incorporated into the facility for absolute containment, remote operation, remote equipment installation, and remote maintenance. The facilities include a battery of nine heavily shielded process cells served by master-slave manipulators and eight laboratories, four on each of two floors. Processing includes chemical dissolution of the targets followed by a series of solvent extraction, ion exchange, and precipitation steps to separate and purify the transuranium elements. The transcurium elements Bk, Cf, Es, and Fm are distributed to users. Remote techniques are used to fabricate the Am and Cm into target rods for reirradiation in the HFIR. Californium-252 that is in excess of the needs of the heavy element research program and the Cf sales program is stored at TRU and processed repeatedly to recover the daughter product 248 Cm, which is a highly desirable research material

Comparison of the Savannah River Site billet active well coincidence counter and two Californium Shufflers

International Nuclear Information System (INIS)

Sadowski, E.T.; Griffin, J.C.; Rinard, P.M.

1991-01-01

A Scrap Californium Shuffler at the Savannah River Site (SRS) was calibrated to assay the U-Al cores of billets (an intermediate step in the SRS reactor fuel fabrication cycle.) The precision of the Scrap Shuffler over several years has been approximately 0.50%. A typical total uncertainty for the assay of a core on the Scrap Shuffler is approximately 0.33% for a twelve minute assay. The precision over several months and a typical total uncertainty for the Billet Active Well (neutron) Coincidence Counter (BAWCC) are approximately 1.0% and 1.9%, respectively, for a fifteen minute assay. A new Billet Californium Shuffler specifically designed for assaying SRS billets has yielded precision (over one month) and total uncertainty results of 0.40% and 0.69%, respectively, for an eight minute assay. The introduction of a measurement point into the fuel fabrication cycle to replace estimates based upon material weight will greatly enhance material and process control in the Reactor Materials area of SRS. The use of all three instruments provides a comparison of the relative merits of Active Well (neutron) Coincidence Counters (AWCCs) and shufflers for assay of homogeneous and geometrically simple material containing 235 U. The measurement precisions, systematic and random uncertainties, as well as the procurement and operation of each instrument will be compared. 3 refs., 5 figs., 1 tab

Synthesis and evaluation of lead telluride/bismuth antimony telluride nanocomposites for thermoelectric applications

International Nuclear Information System (INIS)

Ganguly, Shreyashi; Zhou Chen; Morelli, Donald; Sakamoto, Jeffrey; Uher, Ctirad; Brock, Stephanie L.

2011-01-01

Heterogeneous nanocomposites of p-type bismuth antimony telluride (Bi 2−x Sb x Te 3 ) with lead telluride (PbTe) nanoinclusions have been prepared by an incipient wetness impregnation approach. The Seebeck coefficient, electrical resistivity, thermal conductivity and Hall coefficient were measured from 80 to 380 K in order to investigate the influence of PbTe nanoparticles on the thermoelectric performance of nanocomposites. The Seebeck coefficients and electrical resistivities of nanocomposites decrease with increasing PbTe nanoparticle concentration due to an increased hole concentration. The lattice thermal conductivity decreases with the addition of PbTe nanoparticles but the total thermal conductivity increases due to the increased electronic thermal conductivity. We conclude that the presence of nanosized PbTe in the bulk Bi 2−x Sb x Te 3 matrix results in a collateral doping effect, which dominates transport properties. This study underscores the need for immiscible systems to achieve the decreased thermal transport properties possible from nanostructuring without compromising the electronic properties. - Graphical abstract: PbTe nanoparticles introduced into p-type Bi 2 Te 3 by incipient wetness results in decreased lattice thermal conductivity, but also acts as an electronic dopant, resulting in an overall decrease in thermoelectric performance. Highlights: ► Composites of PbTe nanoparticles in Bi 2−x Sb x Te 3 were formed by incipient wetness. ► PbTe nanoparticles leads to decreased κ l , consistent with phonon scattering. ► PbTe nanoparticles lead to decreased S and ρ, due to increased carriers. ► Collateral doping from PbTe leads to decreased ZT with increasing concentration. ► Immiscible systems are preferred for improved ZT.

Rise time spectroscopy in cadmium telluride detectors

International Nuclear Information System (INIS)

Scharager, Claude; Siffert, Paul; Carnet, Bernard; Le Meur, Roger.

1980-11-01

By a simultaneous analysis of rise time and pulse amplitude distributions of the signals issued from various cadmium telluride detectors, it is possible to obtain informations about surface and bulk trapping, field distribution within the detectors, as well as charge collection and transport properties. These investigations have been performed on both pure and chlorine doped and materials for various surfaces preparation conditions [fr

Process for obtaining oxygen doped zinc telluride monocrystals and scintillator crystals obtained by this process

International Nuclear Information System (INIS)

Schneider, Maurice; Moreau, Roland; D'Haenen, J.-P.; Merenda, Pierre.

1976-01-01

A process is described for obtaining oxygen doped zinc telluride monocrystals, for use as scintillator crystals for ionising radiation detectors. The following operations are carried out in succession: one or several zinc telluride crystals are introduced into a silica ampoule together with a ternary mixture of zinc tellurium and oxygen, as an oxide or hydroxide of these elements; the ampoule is pumped down to a high vacuum and sealed; the sealed ampoule containing the mixture and monocrystals is placed in a kiln and brought to a uniform temperature sufficient to make the mixture three-phased, depending on its composition; the zinc telluride crystalline compound remains solid; the ampoule is then tempered to bring it quickly back to ambient temperature [fr

Measurement of californium-252 gamma photons depth dose distribution in tissue equivalent material. Vol. 4

Energy Technology Data Exchange (ETDEWEB)

Fadel, M A; El-Fiki, M A; Eissa, H M; Abdel-Hafez, A; Naguib, S H [National Institute of Standards, Cairo (Egypt)

1996-03-01

Phantom of tissue equivalent material with and without bone was used measuring depth dose distribution of gamma-rays from californium-252 source. The source was positioned at center of perspex walled phantom. Depth dose measurements were recorded for X, Y and Z planes at different distances from source. TLD 700 was used for measuring the dose distribution. Results indicate that implantation of bone in tissue equivalent medium cause changes in the gamma depth dose distribution which varies according to variation in bone geometry. 9 figs.

Hypoxic versus normoxic external-beam irradiation of cervical carcinoma combined with californium-252 neutron brachytherapy. Comparative treatment results of a 5-year randomized study

Czech Academy of Sciences Publication Activity Database

Tačev, T.; Vacek, Antonín; Ptáčková, B.; Strnad, V.

2005-01-01

Roč. 181, č. 5 (2005), s. 273-284 ISSN 0179-7158 Institutional research plan: CEZ:AV0Z50040507 Keywords : cervical carcinoma * hypoxyradiotherapy * californium-252 Subject RIV: BO - Biophysics Impact factor: 3.490, year: 2005

Ab initio full-potential study of mechanical properties and magnetic phase stability of californium monopnictides (CfN and CfP)

Energy Technology Data Exchange (ETDEWEB)

Amari, S., E-mail: siham_amari@yahoo.fr [Faculté des Sciences de la Nature et de la Vie, Université Hassiba Benbouali, Chlef, 02000 (Algeria); Bouhafs, B. [Laboratoire de Modélisation et Simulation en Sciences des Matériaux, Université Djillali Liabès de Sidi Bel-Abbés, Sidi Bel-Abbés, 22000 (Algeria)

2016-09-15

Based on the first-principles methods, the structural, elastic, electronic, properties and magnetic ordering of californium monopnictides CfX (X = P) have been studied using the full-potential augmented plane wave plus local orbitals (FP-L/APW + lo) method within the framework of density functional theory (DFT). The electronic exchange correlation energy is described by generalized gradient approximation GGA and GGA+U (U is the Hubbard correction). The GGA+U method is applied to the rare-earth 5f states. We have calculated the lattice parameters, bulk modulii and the first pressure derivatives of the bulk modulii. The elastic properties of the studied compounds are only investigated in the most stable calculated phase. In order to gain further information, we have calculated Young’s modulus, shear modulus, anisotropy factor and Kleinman parameter by the aid of the calculated elastic constants. The results mainly show that californium monopnictides CfX (X = P) have an antiferromagnetic spin ordering. Density of states (DOS) and charge densities for both compounds are also computed in the NaCl (B1) structure.

Doping of germanium telluride with bismuth tellurides

International Nuclear Information System (INIS)

Abrikosov, N.Kh.; Karpinskij, O.G.; Makalatiya, T.Sh.; Shelimova, L.E.

1981-01-01

Effect of germanium telluride doping with bismuth fellurides (Bi 2 Te 3 ; BiTe; Bi 2 Te) on phase transition temperature, lattice parameters and electrophysical properties of alloys is studied. It is shown that in alloys of GeTe-Bi 2 Te 3 (BiTe)(Bi 2 Te) cross sections solid solution of GeTe with Bi 2 Te 3 , characterized by deviation from stoichiometry, and germanium in the second phase the quantity of which increases during the transition from GeTe-Bi 2 Te 3 cross section to GeTe-Bi 2 Te are in equilibrium. Lower values of holes concentration and of electric conductivity and higher values of thermo e.m.f. coefficient in comparison with alloys of GeTe-Bi 2 Te 3 cross section with the same bismuth content are characterized for GeTe-Bi 2 Te cross section alloys. It is shown that in the range of GeTe-base solid solution the α→γ phase transformation which runs trough the two-phase region (α→γ) is observed with tellurium content increase. Extension of α-phase existence region widens with the bismuth content increase. Peculiarities of interatomic interaction in GeTe-base solid solutions with isovalent and heterovalent cation substitution are considered [ru

Use of a Soluble Anode in Electrodeposition of Thick Bismuth Telluride Layers

Science.gov (United States)

Maas, M.; Diliberto, S.; de Vaulx, C.; Azzouz, K.; Boulanger, C.

2014-10-01

Integration of thermoelectric devices within an automotive heat exchanger could enable conversion of lost heat into electrical energy, contributing to improved total output from the engine. For this purpose, synthesis of thick bismuth telluride (Bi2Te3) films is required. Bismuth telluride has been produced by an electrochemical method in nitric acid with a sacrificial bismuth telluride anode as the source of cations. The binary layer grows on the working electrode while the counter-electrode, a Bi2Te3 disk obtained by high frequency melting, is oxidized to BiIII and TeIV. This process leads to auto-regeneration of the solution without modification of its composition. The thickness of films deposited by use of the Bi2Te3 anode was approximately 10 times that without. To demonstrate the utility of a soluble anode in electrochemical deposition, we report characterization of the composition and morphology of the films obtained under different experimental conditions. Perfectly dense and regular Bi2Te3 films (˜400 μm) with low internal stress and uniform composition across the cross-section were prepared. Their thermoelectric properties were assessed.

Study of the shielding for spontaneous fission sources of Californium-252; Estudio de blindaje para fuentes de fision espontanea de Californio-252

Energy Technology Data Exchange (ETDEWEB)

Davila R, I

1991-06-15

A shielding study is made to attenuate, until maximum permissible levels, the neutrons radiation and photons emitted by spontaneous fission coming from a source of Californium-252. The compound package by a database (Library DLC-23) and the ANISNW code is used, in it version for personal computer. (Author)

Possible stabilization of the tetravalent oxidation state of berkelium and californium in acetonitrile with triphenylarsine oxide

International Nuclear Information System (INIS)

Payne, G.F.; Peterson, J.R.

1987-01-01

It appears that we may have prepared Bk(IV) nitrate.nTPAs0 and Bk(IV) perchlorate.nTPAs0 complexes which formed the corresponding Cf(IV) complexes through the beta decay of Bk-249. Definitive proof should come from similar experiments with quantities of Bk-249 large enough to allow spectrophotometric detection of the characteristic f→f transitions in these berkelium and californium species. It is clear, however, that TPAs0 and acetonitrile can play a pivotal role in the stabilization of lanact(IV) species

Experimental studies on californium bioavailability to marine benthic invertebrates

International Nuclear Information System (INIS)

Fowler, S.W.; Carvalho, F.P.; Aston, S.R.

1986-01-01

252 Cf is readily taken up by benthic invertebrates from sea water, reaching whole-body concentration factors of 763 in the polychaete Hermione hystrix, 220 in the shrimp Lysmata seticaudata, 665 in the crab Pilumnus hirtellus and 78 in the bivalve mollusc Venerupis decussata after 3 weeks exposure. Surface sorption plays a predominant role in the uptake process. Depuration in clean sea water was a relatively slow process. The shrimp Lysmata eliminated 252 Cf very rapidly due to moulting. Absorption coefficients for ingested 252 Cf were high, approx. 23% in crabs and approx. 97% in brittlestars. The absorbed fraction was excreted twice as fast from crabs as brittlestars. Exposure of organisms to labelled sediment resulted in low transfer factors that were species dependent. There is some evidence to suggest that uptake from sediments is primarily due to 252 Cf transfer from the pore water. Comparison of these results with published experimental data on other transuranic nuclides in the same or similar species suggests that californium bioavailability is roughly equivalent to that of plutonium and americium. (author)

Simulation of core-level binding energy shifts in germanium-doped lead telluride crystals

International Nuclear Information System (INIS)

Zyubin, A.S.; Dedyulin, S.N.; Yashina, L.V.; Shtanov, V.I.

2007-01-01

To simulate the changes in core-level binding energies in germanium-doped lead telluride, cluster calculations of the changes in the electrostatic potential at the corresponding centers have been performed. Different locations of the Ge atom in the crystal bulk have been considered: near vacancies, near another dopant site, and near the surface. For calculating the potential in the clusters that model the bulk and the surface of the lead telluride crystal (c-PbTe), the electron density obtained in the framework of the Hartree-Fock and hybrid density functional theory (DFT) methods has been used [ru

Characterization of large cadmium zinc telluride crystals grown by traveling heater method

DEFF Research Database (Denmark)

Chen, H.; Awadalla, S.A.; Iniewski, K.

2008-01-01

The focus of this paper is to evaluate thick, 20 X 20 X 10 and 10 X 10 X 10 mm(3), cadmium zinc telluride (CZT), Cd0.9Zn0.1Te, crystals grown using the traveling heater method (THIM). The phenomenal spectral performance and small size and low concentration of Te inclusions/precipitates of these c......The focus of this paper is to evaluate thick, 20 X 20 X 10 and 10 X 10 X 10 mm(3), cadmium zinc telluride (CZT), Cd0.9Zn0.1Te, crystals grown using the traveling heater method (THIM). The phenomenal spectral performance and small size and low concentration of Te inclusions...

Diagnostic Genesis Features of Au-Ag Selenide-Telluride Mineralization of Western Java Deposits

Directory of Open Access Journals (Sweden)

Euis Tintin Yuningsih

2016-01-01

Full Text Available DOI: 10.17014/ijog.3.1.67-76The ore mineralogy of the westernmost part of West Java such as Pongkor, Cibaliung, Cikidang, Cikotok, and Cirotan are characterized by the dominance of silver-arsenic-antimony sulfosalt with silver selenides and rarely tellurides over the argentite, whereas the eastern part of West Java including Arinem and Cineam deposits are dominated by silver-gold tellurides. Mineralogy of Se-type deposits at Pongkor, Cikidang, Cibaliung, Cisungsang, and Cirotan and Te-type deposits at Arinem and Cineam shows their different geochemical characteristics. Mineralogical and geochemical differences can be explained by variation of physico-chemical conditions that existed during gold-silver deposition by applying the phase relation among sulfide, telluride, and selenide mineral association in the deposits. The relative values of ƒSe2(g, ƒTe(g, and ƒS2(g control the actual presence of selenide or telluride minerals within the West Java deposits, which also depend on their concentrations in the hydrothermal fluid. Even though the concentration of selenium in the hydrothermal fluid of Te-type deposits might have been similar or even higher than that in the Se-type, early substitution of selenium in the sulfide minerals prevents its concentration in the hydrothermal fluid to the levels for precipitating selenide minerals. Therefore, early sulfide mineral deposition from reduction fluids will not increase the ƒSe2(g/ƒS2(g ratio to form selenide minerals in Te-type deposits of Arinem and Cineam, other than selenium-bearing sulfide mineral such as Se-bearing galena or Se-bearing pyrargyrite-proustite.

Effect of Annealing on the Properties of Antimony Telluride Thin Films and Their Applications in CdTe Solar Cells

Directory of Open Access Journals (Sweden)

Zhouling Wang

2014-01-01

Full Text Available Antimony telluride alloy thin films were deposited at room temperature by using the vacuum coevaporation method. The films were annealed at different temperatures in N2 ambient, and then the compositional, structural, and electrical properties of antimony telluride thin films were characterized by X-ray fluorescence, X-ray diffraction, differential thermal analysis, and Hall measurements. The results indicate that single phase antimony telluride existed when the annealing temperature was higher than 488 K. All thin films exhibited p-type conductivity with high carrier concentrations. Cell performance was greatly improved when the antimony telluride thin films were used as the back contact layer for CdTe thin film solar cells. The dark current voltage and capacitance voltage measurements were performed to investigate the formation of the back contacts for the cells with or without Sb2Te3 buffer layers. CdTe solar cells with the buffer layers can reduce the series resistance and eliminate the reverse junction between CdTe and metal electrodes.

Development of planar waveguides in zinc telluride

International Nuclear Information System (INIS)

Valette, Serge

1977-02-01

Zinc telluride (ZnTe) is one of the most attractive semi-conductors for monolithic integrated optics. In this study, the general characteristics of the planar optical waveguides achieved by implantation of light ions in ZnTe are investigated. Different aspects of prism-coupling and coherent light guiding have been taken up theoretically and experimentally. Some assumptions about the physical origin of these structures are discussed in order to explain all these results and the weak losses which have been measured. [fr

Iron telluride nanorods-based system for the detection of total mercury in blood

Energy Technology Data Exchange (ETDEWEB)

Roy, Prathik; Lin, Zong-Hong [Department of Chemistry, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei 106, Taiwan (China); Liang, Chi-Te [Department of Physics, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei 106, Taiwan (China); Chang, Huan-Tsung, E-mail: changht@ntu.edu.tw [Department of Chemistry, National Taiwan University, 1, Section 4, Roosevelt Road, Taipei 106, Taiwan (China)

2012-12-15

Graphical abstract: Elucidation of the detection of mercury using iron telluride nanorods (FeTe NRs), and dose-response curve for varying concentrations of Hg{sup 2+}. Highlights: Black-Right-Pointing-Pointer Iron telluride nanorods (FeTe NRs) are prepared from tellurium nanowires (Te NWs). Black-Right-Pointing-Pointer Mercury telluride nanorods (HgTe NRs) form by cation exchange reaction of FeTe NRs. Black-Right-Pointing-Pointer Fe{sup 2+} ions released catalyze the oxidation of ABTS by H{sub 2}O{sub 2}. Black-Right-Pointing-Pointer Mercury is effectively determined in blood with an LOD of 1.31 nM at S/N ratio 3. - Abstract: We have developed a simple, colorimetric iron telluride (FeTe) nanorods (NRs) based system for the detection of mercury, mainly based on the cation exchange reaction between FeTe NRs and Hg{sup 2+}. FeTe NRs (length, 105 {+-} 21 nm) react with Hg{sup 2+} to form HgTe NRs (length, 112 {+-} 26 nm) and consequently release Fe{sup 2+} ions that catalyzes the oxidation between a peroxidase substrate 2,2 Prime -azino-bis(3-ethylbenzo-thiazoline-6-sulfonic acid) diammonium salt (ABTS) and H{sub 2}O{sub 2}. The concentration of Fe{sup 2+} and thereby Hg{sup 2+} can be determined by measuring the absorbance of the ABTS oxidized product at 418 nm. This approach allows the detection of Hg{sup 2+}, with a limit of detection of 1.31 nM at a signal-to-noise ratio 3 and a linear range 5-100 nM (R{sup 2} = 0.99). The low-cost, simple, sensitive, and reproducible assay has been validated for the detection of Hg{sup 2+} in a blood sample (SRM 955c), with the result being in good agreement with that provided by National Institute of Standards and Technology.

Feasibility of preparing patterned molybdenum coatings on bismuth telluride thermoelectric modules.

Energy Technology Data Exchange (ETDEWEB)

Sarobol, Pylin; Hall, Aaron Christopher; Miller, Stephen Samuel; Knight, Marlene E.; LePage, William S.; Sobczak, Catherine Elizabeth.; Wesolowski, Daniel Edward

2013-09-01

Molybdenum electrical interconnects for thermoelectric modules were produced by air plasma spraying a 30%CE%BCm size molybdenum powder through a laser-cut Kapton tape mask. Initial feasibility demonstrations showed that the molybdenum coating exhibited excellent feature and spacing retention (~170%CE%BCm), adhered to bismuth-telluride, and exhibited electrical conductivity appropriate for use as a thermoelectric module interconnect. A design of experiments approach was used to optimize air plasma spray process conditions to produce a molybdenum coating with low electrical resistivity. Finally, a molybdenum coating was successfully produced on a fullscale thermoelectric module. After the addition of a final titanium/gold layer deposited on top of the molybdenum coating, the full scale module exhibited an electrical resistivity of 128%CE%A9, approaching the theoretical resistivity value for the 6mm module leg of 112%CE%A9. Importantly, air plasma sprayed molybdenum did not show significant chemical reaction with bismuth-telluride substrate at the coating/substrate interface. The molybdenum coating microstructure consisted of lamellar splats containing columnar grains. Air plasma sprayed molybdenum embedded deeply (several microns) into the bismuth-telluride substrate, leading to good adhesion between the coating and the substrate. Clusters of round pores (and cracks radiating from the pores) were found immediately beneath the molybdenum coating. These pores are believed to result from tellurium vaporization during the spray process where the molten molybdenum droplets (2623%C2%B0C) transferred their heat of solidification to the substrate at the moment of impact. Substrate cooling during the molybdenum deposition process was recommended to mitigate tellurium vaporization in future studies.

Lead telluride with increased mechanical stability for cylindrical thermoelectric generators; Bleitellurid mit erhoehter mechanischer Stabilitaet fuer zylindrische thermoelektrische Generatoren

Energy Technology Data Exchange (ETDEWEB)

Schmitz, Andreas

2013-04-30

The aim of this work is to improve the mechanical stability of lead telluride (PbTe), trying to vary its mechanical properties independently from its thermoelectric properties. Thus the influence of material preparation as well as different dopants on the mechanical and thermoelectric properties of lead telluride is being analysed. When using appropriately set process parameters, milling and sintering of lead telluride increases the material's hardness. With sintering temperatures exceeding 300 C stable material of high relative density can be achieved. Milling lead telluride generates lattice defects leading to a reduction of the material's charge carrier density. These defects can be reduced by increased sintering temperatures. Contamination of the powder due to the milling process leads to bloating during thermal cycling and thus reduced density of the sintered material. In addition to that, evaporation of tellurium at elevated temperatures causes instability of the material's thermoelectric properties. Based on the experimental results obtained in this work, the best thermoelectric and mechanical properties can be obtained by sintering coarse powders at around 400 C. Within this work a concept was developed to vary the mechanical properties of lead telluride via synthesis of PbTe with electrically nondoping elements, which thus may keep the thermoelectric properties unchanged. Therefore, the mechanical and thermoelectric properties of Pb{sub 1-x}Ca{sub x}Te were investigated. Doping pure PbTe with calcium causes a significant increase of the material's hardness while only slightly decreasing the charge carrier density and thus keeping the thermoelectric properties apart from a slight reduction of the electrical conductivity nearly unchanged. The abovementioned concept is proven using sodium doped lead telluride, as it is used for thermoelectric generators: The additional doping with calcium again increases the material's hardness while its thermoelectric

Lead telluride with increased mechanical stability for cylindrical thermoelectric generators; Bleitellurid mit erhoehter mechanischer Stabilitaet fuer zylindrische thermoelektrische Generatoren

Energy Technology Data Exchange (ETDEWEB)

Schmitz, Andreas

2013-04-30

The aim of this work is to improve the mechanical stability of lead telluride (PbTe), trying to vary its mechanical properties independently from its thermoelectric properties. Thus the influence of material preparation as well as different dopants on the mechanical and thermoelectric properties of lead telluride is being analysed. When using appropriately set process parameters, milling and sintering of lead telluride increases the material's hardness. With sintering temperatures exceeding 300 C stable material of high relative density can be achieved. Milling lead telluride generates lattice defects leading to a reduction of the material's charge carrier density. These defects can be reduced by increased sintering temperatures. Contamination of the powder due to the milling process leads to bloating during thermal cycling and thus reduced density of the sintered material. In addition to that, evaporation of tellurium at elevated temperatures causes instability of the material's thermoelectric properties. Based on the experimental results obtained in this work, the best thermoelectric and mechanical properties can be obtained by sintering coarse powders at around 400 C. Within this work a concept was developed to vary the mechanical properties of lead telluride via synthesis of PbTe with electrically nondoping elements, which thus may keep the thermoelectric properties unchanged. Therefore, the mechanical and thermoelectric properties of Pb{sub 1-x}Ca{sub x}Te were investigated. Doping pure PbTe with calcium causes a significant increase of the material's hardness while only slightly decreasing the charge carrier density and thus keeping the thermoelectric properties apart from a slight reduction of the electrical conductivity nearly unchanged. The abovementioned concept is proven using sodium doped lead telluride, as it is used for thermoelectric generators: The additional doping with calcium again increases the material's hardness while

Phase transition of bismuth telluride thin films grown by MBE

DEFF Research Database (Denmark)

Fülöp, Attila; Song, Yuxin; Charpentier, Sophie

2014-01-01

A previously unreported phase transition between Bi2Te3 and Bi4Te3 in bismuth telluride grown by molecular beam epitaxy is recorded via XRD, AFM, and SIMS observations. This transition is found to be related to the Te/Bi beam equivalent pressure (BEP) ratio. BEP ratios below 17 favor the formation...

Californium-252 Brachytherapy Combined With External-Beam Radiotherapy for Cervical Cancer: Long-Term Treatment Results

International Nuclear Information System (INIS)

Lei Xin; Qian Chengyuan; Qing Yi; Zhao Kewei; Yang Zhengzhou; Dai Nan; Zhong Zhaoyang; Tang Cheng; Li Zheng; Gu Xianqing; Zhou Qian; Feng Yan; Xiong Yanli; Shan Jinlu; Wang Dong

2011-01-01

Purpose: To observe, by retrospective analysis, the curative effects and complications due to californium-252 ( 252 Cf) neutron intracavitary brachytherapy (ICBT) combined with external-beam radiotherapy (EBRT) in the treatment of cervical cancer. Methods and Materials: From February 1999 to December 2007, 696 patients with cervical cancer (Stages IB to IIIB) were treated with 252 Cf-ICBT in combination of EBRT. Of all, 31 patients were at Stage IB, 104 at IIA, 363 at IIB, 64 at IIIA, and 134 at IIIB. Californium-252 ICBT was delivered at 7–12 Gy per insertion per week, with a total dose of 29–45 Gy to reference point A in three to five insertions. The whole pelvic cavity was treated with 8-MV X-ray external irradiation at 2 Gy per fraction, four times per week. After 16–38 Gy of external irradiation, the center of the whole pelvic field was blocked with a 4-cm-wide lead shield, with a total external irradiation dose of 44–56 Gy. The total treatment course was 5 to 6 weeks. Results: Overall survival rate at 3 and 5 years for all patients was 76.0% and 64.9%, respectively. Disease-free 3- and 5-year survival rates of patients were 71.2% and 58.4%, respectively. Late complications included vaginal contracture and adhesion, radiation proctitis, radiation cystitis, and inflammatory bowel, which accounted for 5.8%, 7.1%, 6.2%, and 4.9%, respectively. Univariate analysis results showed significant correlation of stage, age, histopathologic grade, and lymph node status with overall survival. Cox multiple regression analysis showed that the independent variables were stage, histopathologic grade, tumor size, and lymphatic metastasis in all patients. Conclusion: Results of this series suggest that the combined use of 252 Cf-ICBT with EBRT is an effective method for treatment of cervical cancer.

Kelvin probe studies of cesium telluride photocathode for AWA photoinjector

Energy Technology Data Exchange (ETDEWEB)

Wisniewski, Eric E., E-mail: ewisniew@anl.gov [High Energy Physics Division, Argonne National Laboratory, 9700 S. Cass, Lemont, IL 60439 (United States); Physics Department, Illinois Institute of Technology, 3300 South Federal Street, Chicago, IL 60616 (United States); Velazquez, Daniel [High Energy Physics Division, Argonne National Laboratory, 9700 S. Cass, Lemont, IL 60439 (United States); Physics Department, Illinois Institute of Technology, 3300 South Federal Street, Chicago, IL 60616 (United States); Yusof, Zikri, E-mail: zyusof@hawk.iit.edu [High Energy Physics Division, Argonne National Laboratory, 9700 S. Cass, Lemont, IL 60439 (United States); Physics Department, Illinois Institute of Technology, 3300 South Federal Street, Chicago, IL 60616 (United States); Spentzouris, Linda; Terry, Jeff [Physics Department, Illinois Institute of Technology, 3300 South Federal Street, Chicago, IL 60616 (United States); Sarkar, Tapash J. [Rice University, 6100 Main, Houston, TX 77005 (United States); Harkay, Katherine [Accelerator Science Division, Argonne National Laboratory, 9700 S. Cass, Lemont, IL 60439 (United States)

2013-05-21

Cesium telluride is an important photocathode as an electron source for particle accelerators. It has a relatively high quantum efficiency (>1%), is sufficiently robust in a photoinjector, and has a long lifetime. This photocathode is grown in-house for a new Argonne Wakefield Accelerator (AWA) beamline to produce high charge per bunch (≈50nC) in a long bunch train. Here, we present a study of the work function of cesium telluride photocathode using the Kelvin probe technique. The study includes an investigation of the correlation between the quantum efficiency and the work function, the effect of photocathode aging, the effect of UV exposure on the work function, and the evolution of the work function during and after photocathode rejuvenation via heating. -- Highlights: ► The correlation between Quantum Efficiency (QE) and work function. ► How QE and work function evolve together. ► Rejuvenation of the photocathode via heating and the effect on work function. ► The effects on the work function due to exposure to UV light.

Teratogenic effect of Californium-252 irradiation in rats

International Nuclear Information System (INIS)

Satow, Yukio; Lee, Juing-Yi; Hori, Hiroshi; Okuda, Hiroe; Tsuchimoto, Shigeo; Sawada, Shozo; Yokoro, Kenjiro

1989-01-01

The teratogenicity of Californium-252 (Cf-252) irradiation which generates approximately 70% 2.3 MeV fast neutron and 30% gamma rays was evaluated. A single whole body exposure of Cf-252 at various doses was given to pregnant rats on day 8 or 9 of pregnancy, followed by microscopic autopsy of the fetuses at the terminal stage of pregnancy to search for external and internal malformations. For comparison, pregnant rats were irradiated with various doses of Cobalt-60 (Co-60) standard gamma rays at the same dose rate (1 rad/min.). The doses were 20-120 rad of Cf-252 and 80-220 rad of Co-60. Using frequency of radiation induced malformations observed on day 8 of pregnancy as an index, relative biological effectiveness (RBE) of 2.3-2.7 was obtained from the straight line obtained by modifying by the least squares method the frequency curves of malformed fetuses in total implants and in surviving fetuses. The types of malformations induced by Cf-252 and Co-60 irradiation were alike. Using fetal LD 50 as an index, 2.4 was obtained as RBE when irradiated on day 8 of pregnancy and 3.1 as that when irradiated on day 9. The results showed that Cf-252 had stronger a teratogenic effect than Co-60 gamma rays. (author)

Mechanism of manganese (mono and di) telluride thin-film formation and properties

Science.gov (United States)

Sharma, Raj Kishore; Singh, Gurmeet; Shul, Yong Gun; Kim, Hansung

2007-03-01

Mechanistic studies on the electrocrystallization of manganese telluride (MnTe) thin film are reported using aqueous acidic solution containing MnSO 4 and TeO 2. Tartaric acid was used for the inhibition of hydrated manganese oxide anodic growth at counter electrode. A detailed study on the mechanistic aspect of electrochemical growth of MnTe using cyclic voltametry is carried out. Conditions for electrochemical growth of manganese mono and di telluride thin films have been reported using cyclic voltammetric scans for Mn 2+, Te 4+ and combined Mn 2+ and Te 4+. X-ray diffraction showed the formation of polycrystalline MnTe films with cubic, hexagonal and orthorhombic mixed phases. MnTe film morphology was studied using scanning electron microscope. Susceptibility and electrical characterization supports the anti-ferromagnetic behavior of the as-deposited MnTe thin film.

Effects of chemical intermixing on electrical and thermal contact conductances at metallized bismuth and antimony telluride interfaces

Energy Technology Data Exchange (ETDEWEB)

Devender,; Mehta, Rutvik J.; Ramanath, Ganpati, E-mail: Ramanath@rpi.edu [Department of Materials Science and Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Lofgreen, Kelly; Mahajan, Ravi [Intel Corporation, Assembly Test and Technology Development, Chandler, Arizona 85226 (United States); Yamaguchi, Masashi [Department of Physics, Applied Physics and Astronomy, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States); Borca-Tasciuc, Theodorian [Department of Mechanical Aerospace and Nuclear Engineering, Rensselaer Polytechnic Institute, Troy, New York 12180 (United States)

2015-03-15

Tailoring electrical and thermal contact conductivities (Σ{sub c} and Γ{sub c}) across metallized pnictogen chalcogenide interfaces is key for realizing efficient thermoelectric devices. The authors report that Cu, Ni, Ti, and Ta diffusion and interfacial telluride formation with n-Bi{sub 2}Te{sub 3} and p-Sb{sub 2}Te{sub 3} influence both Σ{sub c} and Γ{sub c}. Cu metallization yields the highest Γ{sub c} and the lowest Σ{sub c}, correlating with maximal metal diffusion and copper telluride formation. Ni diffuses less and yields the highest Σ{sub c} with Sb{sub 2}Te{sub 3} due to p-type nickel telluride formation, which diminishes Σ{sub c} improvement with n-Bi{sub 2}Te{sub 3} interfaces. Ta and Ti contacts yield the lowest properties similar to that in Ni-metallized structures. These correlations between interfacial diffusion and phase formation on electronic and thermal transport properties will be important for devising suitable metallization for thermoelectric devices.

Application of cadmium telluride detectors to high energy computed tomography

International Nuclear Information System (INIS)

Glasser, F.; Thomas, G.; Cuzin, M.; Verger, L.

1991-01-01

15 years ago, Cadmium Telluride detectors have been investigated in our laboratory as possible detectors for medical scanners [1]. Today most of these machines are using high pressure Xenon gas as multicells detectors, BGO or CdWO 4 scintillators for industrial computerized tomography. Xenon gas detectors are well suited for detection of 100 KeV X-rays and enables to build 1000 cells homogeneous detector with a dynamic range of 3 decades. BGO and CdWO 4 scintillators, associated with photomultipliers or photodiodes are used for higher energy (400 KeV). They present a low afterglow and a dynamic range of 4 to 5 decades. Non destructive testing of very absorbing objects (eg 2 m diameter solid rocket motor) by X-ray tomography requires much higher energy X-rays (16 MeV) and doses up to 12000 rads/min at 1 meter. For this application Cadmium Telluride detectors operating as photoconductors are well suited. A prototype of tomograph machine, able to scan 0.5 m diameter high density objects has been realized with 25 CdTe detectors (25x15x0.8 mm 3 ). It produces good quality 1024x1024 tomographic images

Spatial mapping of cadmium zinc telluride materials properties and electrical response to improve device yield and performance

CERN Document Server

Van Scyoc, J M; Yoon, H; Gilbert, T S; Hilton, N R; Lund, J C; James, R B

1999-01-01

Cadmium zinc telluride has experienced tremendous growth in its application to various radiation sensing problems over the last five years. However, there are still issues with yield, particularly of the large volume devices needed for imaging and sensitivity-critical applications. Inhomogeneities of various types and on various length scales currently prevent the fabrication of large devices of high spectral performance. This paper discusses the development of a set of characterization tools for quantifying these inhomogeneities, in order to develop improvement strategies to achieve the desired cadmium zinc telluride crystals for detector fabrication.

Transport calculations of. gamma. -ray flux density and dose rate about implantable californium-252 sources

Energy Technology Data Exchange (ETDEWEB)

Shapiro, A; Lin, B I [Cincinnati Univ., Ohio (USA). Dept. of Chemical and Nuclear Engineering; Windham, J P; Kereiakes, J G

1976-07-01

..gamma.. flux density and dose rate distributions have been calculated about implantable californium-252 sources for an infinite tissue medium. Point source flux densities as a function of energy and position were obtained from a discrete-ordinates calculation, and the flux densities were multiplied by their corresponding kerma factors and added to obtain point source dose rates. The point dose rates were integrated over the line source to obtain line dose rates. Container attenuation was accounted for by evaluating the point dose rate as a function of platinum thickness. Both primary and secondary flux densities and dose rates are presented. The agreement with an independent Monte Carlo calculation was excellent. The data presented should be useful for the design of new source configurations.

Gamma-ray peak shapes from cadmium zinc telluride detectors

Energy Technology Data Exchange (ETDEWEB)

Namboodiri, M.N.; Lavietes, A.D.; McQuaid, J.H.

1996-09-01

We report the results of a study of the peak shapes in the gamma spectra measured using several 5 x 5 x 5 mm{sup 3} cadmium zinc telluride (CZT) detectors. A simple parameterization involving a Gaussian and an exponential low energy tail describes the peak shapes sell. We present the variation of the parameters with gamma energy. This type of information is very useful in the analysis of complex gamma spectra consisting of many peaks.

Diffusion of iron in β-iron telluride (Fe1.12Te) by Moessbauer spectroscopy and tracer method

International Nuclear Information System (INIS)

Magara, Masaaki; Tsuji, Toshihide; Naito, Keiji

1993-01-01

The diffusion coefficient of iron in a β-iron telluride (Fe 1.12 Te) polycrystalline sample was measured by Moessbauer diffusional line broadening method which relates to the collapse of coherence in gamma-ray photon by the atomic jump at local sites. The diffusion coefficient of iron along the c-axis in nearly single crystal of β-iron telluride was also measured by tracer technique which shows the results of an atom transport in long distance. The activation energies for the diffusion of iron in Fe 1.12 Te obtained by the Moessbauer spectroscopy and the tracer method were 91.5±5.4 and 106±23 kJ/mol, respectively. The diffusion coefficients of iron in β-iron telluride obtained by Moessbauer line broadening are in fair agreement with the values averaged from that along c-axis obtained by tracer method and that along a- and b-axes obtained from reaction rate constant between iron and tellurium by the previous study of the present authors. (orig.)

XAFS studies of nickel-doped lead telluride

International Nuclear Information System (INIS)

Radisavljevic, Ivana; Novakovic, Nikola; Ivanovic, Nenad; Romcevic, Nebojsa; Manasijevic, Miodrag; Mahnke, Heinz-Eberhard

2009-01-01

The problem of impurities and defect states in lead telluride-based semiconductors is of crucial importance for their practical applications. X-ray absorption fine structure (XAFS) techniques are capable to address some of the key issues regarding impurities position, their valent state, as well as the local structural changes of the host lattice in the immediate surrounding of the impurity atoms. In this paper we present the results of the Ni K-absorption edge XAFS studies of Ni-doped PbTe at different temperatures. Analysis of near edge and extended XAFS regions of the measured spectra provided information about exact local environment and lattice ordering around Ni atoms.

Beyond Californium-A Neutron Generator Alternative for Dosimetry and Instrument Calibration in the U.S.

Science.gov (United States)

Piper, Roman K; Mozhayev, Andrey V; Murphy, Mark K; Thompson, Alan K

2017-09-01

Evaluations of neutron survey instruments, area monitors, and personal dosimeters rely on reference neutron radiations, which have evolved from the heavy reliance on (α,n) sources to a shared reliance on (α,n) and the spontaneous fission neutrons of californium-252 (Cf). Capable of producing high dose equivalent rates from an almost point source geometry, the characteristics of Cf are generally more favorable when compared to the use of (α,n) and (γ,n) sources or reactor-produced reference neutron radiations. Californium-252 is typically used in two standardized configurations: unmoderated, to yield a fission energy spectrum; or with the capsule placed within a heavy-water moderating sphere to produce a softened spectrum that is generally considered more appropriate for evaluating devices used in nuclear power plant work environments. The U.S. Department of Energy Cf Loan/Lease Program, a longtime origin of affordable Cf sources for research, testing and calibration, was terminated in 2009. Since then, high-activity sources have become increasingly cost-prohibitive for laboratories that formerly benefited from that program. Neutron generators, based on the D-T and D-D fusion reactions, have become economically competitive with Cf and are recognized internationally as important calibration and test standards. Researchers from the National Institute of Standards and Technology and the Pacific Northwest National Laboratory are jointly considering the practicality and technical challenges of implementing neutron generators as calibration standards in the U.S. This article reviews the characteristics of isotope-based neutron sources, possible isotope alternatives to Cf, and the rationale behind the increasing favor of electronically generated neutron options. The evaluation of a D-T system at PNNL has revealed characteristics that must be considered in adapting generators to the task of calibration and testing where accurate determination of a dosimetric quantity is

Control of p-type and n-type thermoelectric properties of bismuth telluride thin films by combinatorial sputter coating technology

International Nuclear Information System (INIS)

Goto, Masahiro; Sasaki, Michiko; Xu, Yibin; Zhan, Tianzhuo; Isoda, Yukihiro; Shinohara, Yoshikazu

2017-01-01

Highlights: • p- and n-type bismuth telluride thin films have been synthesized using a combinatorial sputter coating system (COSCOS) while changing only one of the experimental conditions, the RF power. • The dimensionless figure of merit (ZT) was optimized by the technique. • The fabrication of a Π-structured TE device was demonstrated. - Abstract: p- and n-type bismuth telluride thin films have been synthesized by using a combinatorial sputter coating system (COSCOS). The crystal structure and crystal preferred orientation of the thin films were changed by controlling the coating condition of the radio frequency (RF) power during the sputter coating. As a result, the p- and n-type films and their dimensionless figure of merit (ZT) were optimized by the technique. The properties of the thin films such as the crystal structure, crystal preferred orientation, material composition and surface morphology were analyzed by X-ray diffraction, energy-dispersive X-ray spectroscopy and atomic force microscopy. Also, the thermoelectric properties of the Seebeck coefficient, electrical conductivity and thermal conductivity were measured. ZT for n- and p-type bismuth telluride thin films was found to be 0.27 and 0.40 at RF powers of 90 and 120 W, respectively. The proposed technology can be used to fabricate thermoelectric p–n modules of bismuth telluride without any doping process.

Control of p-type and n-type thermoelectric properties of bismuth telluride thin films by combinatorial sputter coating technology

Energy Technology Data Exchange (ETDEWEB)

Goto, Masahiro, E-mail: goto.masahiro@nims.go.jp [Thermoelectric Materials Group, Center for Green Research on Energy and Environmental Materials, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Thermal Management and Thermoelectric Materials Group, Center for Materials Research by Information Integration (CMI2), National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Sasaki, Michiko [Thermal Management and Thermoelectric Materials Group, Center for Materials Research by Information Integration (CMI2), National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Xu, Yibin [Thermal Management and Thermoelectric Materials Group, Center for Materials Research by Information Integration (CMI2), National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Materials Database Group, Center for Materials Research by Information Integration (CMI2), National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Zhan, Tianzhuo [Thermal Management and Thermoelectric Materials Group, Center for Materials Research by Information Integration (CMI2), National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Isoda, Yukihiro [Thermoelectric Materials Group, Center for Green Research on Energy and Environmental Materials, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Shinohara, Yoshikazu [Thermoelectric Materials Group, Center for Green Research on Energy and Environmental Materials, National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan); Thermal Management and Thermoelectric Materials Group, Center for Materials Research by Information Integration (CMI2), National Institute for Materials Science, 1-2-1 Sengen, Tsukuba, Ibaraki 305-0047 (Japan)

2017-06-15

Highlights: • p- and n-type bismuth telluride thin films have been synthesized using a combinatorial sputter coating system (COSCOS) while changing only one of the experimental conditions, the RF power. • The dimensionless figure of merit (ZT) was optimized by the technique. • The fabrication of a Π-structured TE device was demonstrated. - Abstract: p- and n-type bismuth telluride thin films have been synthesized by using a combinatorial sputter coating system (COSCOS). The crystal structure and crystal preferred orientation of the thin films were changed by controlling the coating condition of the radio frequency (RF) power during the sputter coating. As a result, the p- and n-type films and their dimensionless figure of merit (ZT) were optimized by the technique. The properties of the thin films such as the crystal structure, crystal preferred orientation, material composition and surface morphology were analyzed by X-ray diffraction, energy-dispersive X-ray spectroscopy and atomic force microscopy. Also, the thermoelectric properties of the Seebeck coefficient, electrical conductivity and thermal conductivity were measured. ZT for n- and p-type bismuth telluride thin films was found to be 0.27 and 0.40 at RF powers of 90 and 120 W, respectively. The proposed technology can be used to fabricate thermoelectric p–n modules of bismuth telluride without any doping process.

GEOLOGY OF THE FLORENCIA GOLD – TELLURIDE DEPOSIT (CAMAGÜEY, CUBA AND SOME METALLURGICAL CONSIDERATIONS

Directory of Open Access Journals (Sweden)

López K Jesús M.

2006-12-01

Full Text Available This paper describes the results from a study of the Florencia gold-telluride deposit in Central Cuba, including mineralogical, petrographical, microprobe and chemical analysis. Valuable information is provided for the exploration, mining and processing of gold ores from other nearby deposits with similar characteristics. Results highlight changes in the mineralogical composition of the ores between the north and south sectors of the deposit, as reflected in metallurgical concentrates after beneficiation and flotation of samples from these sectors.
It is shown that gold deposits of the Cretaceous Volcanic Arc of Cuba largely consist of native gold, telluride and pyrite, where arsenopyrite is almost absent. Traces of lead, zinc and cadmium are present in the periphery of the main ore zones.

Neutron activation analysis at the Californium User Facility for Neutron Science

International Nuclear Information System (INIS)

Martin, R.C.; Smith, E.H.; Glasgow, D.C.; Jerde, E.A.; Marsh, D.L.; Zhao, L.

1997-12-01

The Californium User Facility (CUF) for Neutron Science has been established to provide 252 Cf-based neutron irradiation services and research capabilities including neutron activation analysis (NAA). A major advantage of the CUF is its accessibility and controlled experimental conditions compared with those of a reactor environment The CUF maintains the world's largest inventory of compact 252 Cf neutron sources. Neutron source intensities of ≤ 10 11 neutrons/s are available for irradiations within a contamination-free hot cell, capable of providing thermal and fast neutron fluxes exceeding 10 8 cm -2 s -1 at the sample. Total flux of ≥10 9 cm -2 s -1 is feasible for large-volume irradiation rabbits within the 252 Cf storage pool. Neutron and gamma transport calculations have been performed using the Monte Carlo transport code MCNP to estimate irradiation fluxes available for sample activation within the hot cell and storage pool and to design and optimize a prompt gamma NAA (PGNAA) configuration for large sample volumes. Confirmatory NAA irradiations have been performed within the pool. Gamma spectroscopy capabilities including PGNAA are being established within the CUF for sample analysis

Magneto-photoconductivity of three dimensional topological insulator bismuth telluride

Science.gov (United States)

Cao, Bingchen; Eginligil, Mustafa; Yu, Ting

2018-03-01

Magnetic field dependence of the photocurrent in a 3D topological insulator is studied. Among the 3D topological insulators bismuth telluride has unique hexagonal warping and spin texture which has been studied by photoemission, scanning tunnelling microscopy and transport. Here, we report on low temperature magneto-photoconductivity, up to 7 T, of two metallic bismuth telluride topological insulator samples with 68 and 110 nm thicknesses excited by 2.33 eV photon energy along the magnetic field perpendicular to the sample plane. At 4 K, both samples exhibit negative magneto-photoconductance below 4 T, which is as a result of weak-antilocalization of Dirac fermions similar to the previous observations in electrical transport. However the thinner sample shows positive magneto-photoconductance above 4 T. This can be attributed to the coupling of surface states. On the other hand, the thicker sample shows no positive magneto-photoconductance up to 7 T since there is only one surface state at play. By fitting the magneto-photoconductivity data of the thicker sample to the localization formula, we obtain weak antilocalization behaviour at 4, 10, and 20 K, as expected; however, weak localization behaviour at 30 K, which is a sign of surface states masked by bulk states. Also, from the temperature dependence of phase coherence length bulk carrier-carrier interaction is identified separately from the surface states. Therefore, it is possible to distinguish surface states by magneto-photoconductivity at low temperature, even in metallic samples.

Application of californium-252 neutron sources for analytical chemistry

International Nuclear Information System (INIS)

Ishii, Daido

1976-01-01

The researches made for the application of Cf-252 neutron sources to analytical chemistry during the period from 1970 to 1974 including partly 1975 are reviewed. The first part is the introduction to the above. The second part deals with general review of symposia, publications and the like. Attention is directed to ERDA publishing the periodical ''Californium-252 Progress'' and to a study group of Cf-252 utilization held by Japanese Radioisotope Association in 1974. The third part deals with its application for radio activation analysis. The automated absolute activation analysis (AAAA) of Savannha River is briefly explained. The joint experiment of Savannha River operation office with New Brunswick laboratory is mentioned. Cf-252 radiation source was used for the non-destructive analysis of elements in river water. East neutrons of Cf-252 were used for the quantitative analysis of lead in paints. Many applications for industrial control processes have been reported. Attention is drawn to the application of Cf-252 neutron sources for the field search of neutral resources. For example, a logging sonde for searching uranium resources was developed. the fourth part deals with the application of the analysis with gamma ray by capturing neutrons. For example, a bore hole sonde and the process control analysis of sulfur in fuel utilized capture gamma ray. The prompt gamma ray by capturing neutrons may be used for the nondestructive analysis of enrivonment. (Iwakiri, K.)

Spectral investigation of neutron radiation in three-sectional concrete labyrinth from a californium-252 source

International Nuclear Information System (INIS)

Belogorlov, E.A.; Britvich, G.I.; Getmanov, V.B.

1985-01-01

Construction of labyrinths in points of communication output from the storage-ring under construction is accompanied by numerous difficulties due to a considerable number of gas and cryogenic pipelines, which require large cross sections at the minimal length of the pipelines proper for their location. It results in unfavourable for radiation attenuation ratios between cross section and length of the labyrinth separate sections. Neutron spectra in a model concrete labyrinth, at the entrance to which a neutron source with fission spectrum (californium-252) and the same source in a polyethylene moderator are located, are measured. On the basis of the spectra obtained the formation of fluence and equivalent dose along the labyrinth geometric axis is analyzed. Conditions permitting actually to reduce radiation dose in the labyrinth (dead end provision, the use of cover materials, construction of diaphragms and shielding plates) are simulated

Megapixel mercury cadmium telluride focal plane arrays for infrared imaging out to 12 microns, Phase I

Data.gov (United States)

National Aeronautics and Space Administration — We propose the fabrication of large format, long wave infrared (LWIR) mercury cadmium telluride (HgCdTe or MCT) detector arrays where the cutoff wavelength is...

Synthesis of ultra-long cadmium telluride nanotubes via combinational chemical transformation

Energy Technology Data Exchange (ETDEWEB)

Park, Kee-Ryung; Cho, Hong-Baek; Choa, Yong-Ho, E-mail: choa15@hanyang.ac.kr

2017-03-01

Synthesis of high-throughput cadmium telluride (CdTe) nanotubes with an ultra-long aspect ratio is presented via a combination process concept combined with electrospinning, electrodeposition, and cationic exchange reaction. Ultra-long sacrificial silver (Ag) nanofibers were synthesized by electrospinning involving two-step calcination, and were then electrodeposited to create silver telluride nanotubes. These nanotubes underwent cationic exchange reaction in cadmium nitrate tetrahydrate solution with the aid of a ligand, tributylphosphine (TBP). Analysis showed that ultra-long pure zinc blende CdTe nanotubes were obtained with controlled dimension and uniform morphology. The thermodynamic driving force induced by the coordination of methanol solvent and TBP attributed to overcome the kinetic barrier between Ag{sub 2}Te and CdTe nanotubes, facilitating the synthesis of CdTe nanotubes. This synthetic process involving a topotactic reaction route paves a way for high-throughput extended synthesis of new chalcogenide hollow nanotubes for application in photodetectors and solar cells. - Highlights: • High throughput synthetic route of hollow CdTe nanotubes with ultra-long aspect ratio. • Chemical combination of electrospinning, electrodeposition & cation exchange reaction. • Pure zinc blende CdTe by controlled dimension & structural variation of Ag nanofibers. • Potential for the high throughput synthesis of new exotic chalcogenide nanotubes.

Strain effect on the heat transport properties of bismuth telluride nanofilms with a hole

Science.gov (United States)

Fang, Te-Hua; Chang, Win-Jin; Wang, Kuan-Yu; Huang, Chao-Chun

2018-06-01

We investigated the mechanical behavior of bismuth telluride nanofilms with holes by using an equilibrium molecular dynamics (MD) approach. The holes had diameters of 20, 30, 40, and 50 Å. The thermal conductivity values of the nanofilms were calculated under different strains at different temperatures using a nonequilibrium MD simulation. The simulation revealed that the thermal conductivity of a bismuth telluride nanofilm with a hole decreases with an increase in hole diameter at different strains. For a film with a perfect structure at 300 K, a 48% reduction (from 0.33 to 0.17 W/m K) in the thermal conductivity was observed at a 7% tensile strain. In addition, the thermal conductivity increased by approximately 39% (from 0.33 to 0.46 W/m K) at a 7% compressive strain. A very low value (0.11 W/m K) of thermal conductivity is obtained for the nanofilm with a hole diameter of 50 Å at a 7% tensile strain at 300 K.

Possible bicollinear nematic state with monoclinic lattice distortions in iron telluride compounds

Energy Technology Data Exchange (ETDEWEB)

Bishop, Christopher B. [Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Herbrych, Jacek W. [Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Dagotto, Elbio R. [Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Moreo, Adriana [Univ. of Tennessee, Knoxville, TN (United States); Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-07-15

Here, iron telluride (FeTe) is known to display bicollinear magnetic order at low temperatures together with a monoclinic lattice distortion. Because the bicollinear order can involve two different wave vectors (π/2,π/2) and (π/2,–π/2), symmetry considerations allow for the possible stabilization of a nematic state with short-range bicollinear order coupled to monoclinic lattice distortions at a T_S higher than the temperature T_N where long-range bicollinear order fully develops. As a concrete example, the three-orbital spin-fermion model for iron telluride is studied with an additional coupling ˜λ₁₂ between the monoclinic lattice strain and an orbital-nematic order parameter with B_2g symmetry. Monte Carlo simulations show that with increasing ˜λ₁₂ the first-order transition characteristic of FeTe splits and bicollinear nematicity is stabilized in a (narrow) temperature range. In this new regime, the lattice is monoclinically distorted and short-range spin and orbital order breaks rotational invariance. A discussion of possible realizations of this exotic state is provided.

Specific features of the photoconductivity of semi-insulating cadmium telluride

Energy Technology Data Exchange (ETDEWEB)

Golubyatnikov, V. A.; Grigor’ev, F. I.; Lysenko, A. P., E-mail: aplysenko@hse.ru; Strogankova, N. I.; Shadov, M. B. [National Research University Higher School of Economics, Moscow Institute of Electronics and Mathematics (Russian Federation); Belov, A. G. [OAO GIREDMET State Research and Design Institute of the Rare-Metal Industry (Russian Federation)

2014-12-15

The effect of local illumination providing a high level of free-carrier injection on the conductivity of a sample of semi-insulating cadmium telluride and on the properties of ohmic contacts to the sample is studied. It is found that, irrespective of the illumination region, the contact resistance of ohmic contacts decreases and the concentration of majority carriers in the sample grows in proportion to the illumination intensity. It is shown that inherent heterogeneities in crystals of semi-insulating semiconductors can be studied by scanning with a light probe.

Use of polyethylene pellets in the design and construction of a storage safe, a transport vessel and a portable shield for californium-252

International Nuclear Information System (INIS)

Sharma, S.

1986-01-01

A storage and shielding facility for 300 μg of Californium-252 sources was designed and constructed. Though the safe was in a permanent location, the fact that it consisted of a lead bucket surrounded by polyethylene pellets made it simple, movable and inexpensive. If need be, more quantities of Cf-252 could be added without altering the basic design and sacrificing the radiation protection guidelines. The measured radiation levels from 300 μg of stored Cf-252 in and around the storage vault were lower than the expected dose rates by a factor of 5. The measured radiation levels around the occupied environs of the facility were below the maximum permissible yearly dose of 500mrem for non-occupational workers. A transport vessel was designed and constructed to carry up to 50 μg of Californium-252 sources. It consisted of a standard 55 gallon steel drum on casters containing cylindrical lead shield surrounded by polyethylene pellets. The measured maximum surface dose rates on the drum and at one meter away were within the radiation protection guidelines and were less than the expected dose rates. A portable shield was designed and constructed to protect the body in afterloading operations and handling of the sources. It consisted of polyethylene pellets in an aluminum box and an attached 10 cm thick plexiglass eye shield. The simple design, with the ease of using polyethylene pellets can be extended to construct bedside shields

Electrical properties of cadmium telluride films doped with antimony

International Nuclear Information System (INIS)

Atdaev, B.S.; Garyagdyev, G.; Grin', V.F.; Noskov, A.I.

1989-01-01

Effect of cadmium telluride doping with antimony on electric and photoelectric properties is investigated. Temperature dependence of dark (σ d ) and photoconductivity (σ p ) during excitation from the range of proper absorption in the temperature range 77-300 K and spectral distribution of photoconductivity at 300 K are investigated. It is shown that in the process of doping antimony diffusses intensively over CdTe grain boundaries, decreasing potential barriers between them and due to diffusion into CdTe grains it changes their electrical properties. The acceptor character of antimony impurity can be caused by antimony diffusion into tellurium sublattice owing to proximity of their ionic and covalent radii

Donor impurity self-compensation by neutral complexes in bismuth doped lead telluride

International Nuclear Information System (INIS)

Ravich, Yu.I.; Nemov, S.A.; Proshin, V.I.

1994-01-01

Self-compensation is calculated of impurity doping action in semiconductors of the A 4 B 6 type by neutral complexes, consisting of a vacancy and two impurity atoms. Complexes entropy is estimated and the thermodynamic potential is minimized in the concentration of single two-charge vacancies and complexes. Calculation results are compared with experimental data, obtained when lead telluride doping by bismuth. Account for complex formation improves agreement theory with experiment. 4 refs., 1 fig

Crystalline perfection and mechanical investigations on vertical Bridgman grown Bismuth telluride (Bi_2Te_3) single crystals for thermoelectric applications

International Nuclear Information System (INIS)

Krishna, Anuj; Vijayan, N.; Singh, Budhendra; Thukral, Kanika; Maurya, K.K.

2016-01-01

High efficiency thermoelectric materials plays a vital role in power generation and refrigeration applications. Bismuth telluride (Bi_2Te_3) is one among them. In the present work single crystal of bismuth telluride was grown using vertical Bridgman technique. The phase of grown crystals was analysed using a powder X-ray diffractometer. Quality of the grown crystal was assessed by using high resolution X-ray diffractometer and observed that it is fairly good. Further mechanical investigations on grown crystal was carried out using nano-indentation technique and various mechanical properties like hardness, stiffness and Young’s modulus were evaluated. Observed results clearly indicate its suitability for thermoelectric applications.

Structure impact on the thermal and electronic properties of bismuth telluride by ab-initio and molecular dynamics calculations

International Nuclear Information System (INIS)

Termentzidis, K; Pokropivny, A; Xiong, S-Y; Chumakov, Y; Volz, S; Woda, M; Cortona, P

2012-01-01

We use molecular dynamics and ab-initio methods to predict the thermal and electronic properties of new materials with high figures of merit. The simulated systems are bulk bismuth tellurides with antisite and vacancy defects. Optimizations of the materials under investigation are performed by the SIESTA code for subsequent calculations of force constants, electronic properties, and Seebeck coefficients. The prediction of the thermal conductivity is made by Non-Equilibrium Molecular Dynamics (NEMD) using the LAMMPS code. The thermal conductivity of bulk bismuth telluride with different stoichiometry and with a number of substitution defects is calculated. We have found that the thermal conductivity can be decreased by 60% by introducing vacancy defects. The calculated thermal conductivities for the different structures are compared with the available experimental and theoretical results.

Extraction of Trivalent Actinides and Lanthanides from Californium Campaign Rework Solution Using TODGA-based Solvent Extraction System

Energy Technology Data Exchange (ETDEWEB)

Benker, Dennis [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Delmau, Laetitia Helene [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Dryman, Joshua Cory [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-07-01

This report presents the studies carried out to demonstrate the possibility of quantitatively extracting trivalent actinides and lanthanides from highly acidic solutions using a neutral ligand-based solvent extraction system. These studies stemmed from the perceived advantage of such systems over cationexchange- based solvent extraction systems that require an extensive feed adjustment to make a low-acid feed. The targeted feed solutions are highly acidic aqueous phases obtained after the dissolution of curium targets during a californium (Cf) campaign. Results obtained with actual Cf campaign solutions, but highly diluted to be manageable in a glove box, are presented, followed by results of tests run in the hot cells with Cf campaign rework solutions. It was demonstrated that a solvent extraction system based on the tetraoctyl diglycolamide molecule is capable of quantitatively extracting trivalent actinides from highly acidic solutions. This system was validated using actual feeds from a Cf campaign.

Neutron activation analysis of the calcium content in vivo, using a 50μg source of californium 252

International Nuclear Information System (INIS)

Guey, A.; Zech, P.Y.; Meary, M.F.; Leitienne, P.

1975-01-01

Owing to the recent commercialisation of californium 252 it is now possible to obtain neutron fluxes strong enough for precise activation of the calcium content of biological targets. After the preliminary measurements necessary to establish the most suitable conditions for irradiating 3 to 5cm thick targets, two parallel sets of experiments were developed. In the first the medium-term total calcium variation was studied in 20 rats, 16 suffering from chronic kidney deficiency. In the second the precision expected as a function of the calcium content of the irradiated target was examined, using 3 sets of tissue equivalent standards of calcium contents 5, 20 and 50g respectively. The first results obtained on calcium 49 in vivo show that a calcium content variation can be followed with a sensitivity threshold below that obtained by conventional methods [fr

Electrochemical Studies of Lead Telluride Behavior in Acidic Nitrate Solutions

Directory of Open Access Journals (Sweden)

Rudnik E.

2015-04-01

Full Text Available Electrochemistry of lead telluride stationary electrode was studied in nitric acid solutions of pH 1.5-3.0. E-pH diagram for Pb-Te-H2O system was calculated. Results of cyclic voltammetry of Pb, Te and PbTe were discussed in correlation with thermodynamic predictions. Anodic dissolution of PbTe electrode at potential approx. -100÷50 mV (SCE resulted in tellurium formation, while above 300 mV TeO2 was mainly produced. The latter could dissolve to HTeO+2 under acidic electrolyte, but it was inhibited by increased pH of the bath.

Cadmium telluride gamma-radiation detectors with a high energy resolution

International Nuclear Information System (INIS)

Alekseeva, L.A.; Dorogov, P.G.; Ivanov, V.I.; Khusainov, A.K.

1985-01-01

This paper considers the possibility of improving the energy resolution of cadmium telluride gamma-radiation detectors through the choice of the geometry and size of the sensitive region of the detector. The optimum ratio of the product of the mobility and lifetime for electrons to the same product for holes from the point of view of energy resolution is greater than or equal to 10 2 for a detector of spherical geometry and should be less than or equal to 10 for a cylindrical geometry and approximately 1 for a planar geometry. The optimum values of the major and minor radii of a spherical detector are calculated

Crystalline perfection and mechanical investigations on vertical Bridgman grown Bismuth telluride (Bi{sub 2}Te{sub 3}) single crystals for thermoelectric applications

Energy Technology Data Exchange (ETDEWEB)

Krishna, Anuj [Academy of Scientific and Innovative Research, CSIR- National Physical Laboratory, New Delhi 110012 (India); X-ray Analysis and Crystal Growth Section, CSIR-National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India); Vijayan, N., E-mail: nvijayan@nplindia.org [X-ray Analysis and Crystal Growth Section, CSIR-National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India); Singh, Budhendra [TEMA-NRD, Mechanical Engineering Department and Aveiro Institute of Nanotechnology (AIN), University of Aveiro, 3810-193 Aveiro (Portugal); Thukral, Kanika [Academy of Scientific and Innovative Research, CSIR- National Physical Laboratory, New Delhi 110012 (India); X-ray Analysis and Crystal Growth Section, CSIR-National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India); Maurya, K.K. [X-ray Analysis and Crystal Growth Section, CSIR-National Physical Laboratory, Dr. K.S. Krishnan Road, New Delhi 110012 (India)

2016-03-07

High efficiency thermoelectric materials plays a vital role in power generation and refrigeration applications. Bismuth telluride (Bi{sub 2}Te{sub 3}) is one among them. In the present work single crystal of bismuth telluride was grown using vertical Bridgman technique. The phase of grown crystals was analysed using a powder X-ray diffractometer. Quality of the grown crystal was assessed by using high resolution X-ray diffractometer and observed that it is fairly good. Further mechanical investigations on grown crystal was carried out using nano-indentation technique and various mechanical properties like hardness, stiffness and Young’s modulus were evaluated. Observed results clearly indicate its suitability for thermoelectric applications.

Use of californium-252 neutron irradiator for in-vivo analysis of the bone calcium content of the hand

International Nuclear Information System (INIS)

Guey, A.; Leitienne, P.; Zech, P.Y.; Traeger, J.; Doyen, J.B.; Breton, J.P.

1979-01-01

With californium-252 it is easy to obtain a high neutron flux of the order of 10 9 n/s. The mean energy of this radiation, which is close on 2 MeV, activates calcium very well. The authors describe a storage and irradiator unit with a 100 μg californium source, with which it will henceforth be possible to develop this technique of measuring the calcium of the hand in a hospital. The test programme has three distinct phases: (1) irradiation of the biological target for 10 min; (2) after a transfer period of 30 s, detection of the radiation emitted by the 49 Ca for 600 s; (3) processing of the numerical data received, which are transmitted on line to a T 1600 calculator. The weight is found by comparing the activity induced in the unknown calcium mass with that induced in a phantom chosen as the activity standard. The reproducibility of the method is of the order of 3% (5% at the worst). The gross standardized result is edited automatically. For physical and clinical reasons, the hand is chosen as the reference part of the body in 70 control subjects. The local irradiation dose is less than 2 rem. The bone calcium content is 14.3+-1.9 g in men and 10.1+-1.3 g in women. In clinical application of the technique it is necessary to differentiate between the normal calcium content and the calcium content found with a pathological state. This makes it necessary to express the measurement in the form of a volume mass (rho). The volume of the hand skeleton (V in cm 3 ) is calculated from the corresponding bone surface (S in cm 2 ) measured by planimetry with the relationship V=8.925 exp 0.0205.S, found after studying 80 hand skeletons. In our control subjects the calcium bone volume mass was 0.288 g/cm 3 in men and 0.282 g/cm 3 in women. There is a very significant difference (p<0.001) in a population of 88 subjects with chronic renal insufficiencies at the terminal stage: rho=0.233 in men and 0.235 in women

Simulation and design of an electron beam ion source charge breeder for the californium rare isotope breeder upgrade

Directory of Open Access Journals (Sweden)

Clayton Dickerson

2013-02-01

Full Text Available An electron beam ion source (EBIS will be constructed and used to charge breed ions from the californium rare isotope breeder upgrade (CARIBU for postacceleration into the Argonne tandem linear accelerator system (ATLAS. Simulations of the EBIS charge breeder performance and the related ion transport systems are reported. Propagation of the electron beam through the EBIS was verified, and the anticipated incident power density within the electron collector was identified. The full normalized acceptance of the charge breeder with a 2 A electron beam, 0.024π  mm mrad for nominal operating parameters, was determined by simulating ion injection into the EBIS. The optics of the ion transport lines were carefully optimized to achieve well-matched ion injection, to minimize emittance growth of the injected and extracted ion beams, and to enable adequate testing of the charge bred ions prior to installation in ATLAS.

Effect of electronic contribution on temperature-dependent thermal transport of antimony telluride thin film

Energy Technology Data Exchange (ETDEWEB)

Lee, Won-Yong; Park, No-Won [Department of Physics, Chung-Ang University, Seoul 156-756 (Korea, Republic of); Hong, Ji-Eun [Department of Materials Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Yoon, Soon-Gil, E-mail: sgyoon@cnu.ac.kr [Department of Materials Engineering, Chungnam National University, Daejeon 305-764 (Korea, Republic of); Koh, Jung-Hyuk [School of Electrical and Electronics Engineering, Chung-Ang University, Seoul 156-756 (Korea, Republic of); Lee, Sang-Kwon, E-mail: sangkwonlee@cau.ac.kr [Department of Physics, Chung-Ang University, Seoul 156-756 (Korea, Republic of)

2015-01-25

Highlights: • We investigated thermal transport of the antimony telluride thin films. • The contribution of the electronic thermal conductivity increased up to ∼77% at 300 K. • We theoretically analyze and explain the high contribution of electronic component. - Abstract: We study the theoretical and experimental characteristics of thermal transport of 100 nm and 500 nm-thick antimony telluride (Sb{sub 2}Te{sub 3}) thin films prepared by radio frequency magnetron sputtering. The thermal conductivity was measured at temperatures ranging from 20 to 300 K, using four-point-probe 3-ω method. Out-of-plane thermal conductivity of the Sb{sub 2}Te{sub 3} thin film was much lesser in comparison to the bulk material in the entire temperature range, confirming that the phonon- and electron-boundary scattering are enhanced in thin films. Moreover, we found that the contribution of the electronic thermal conductivity (κ{sub e}) in total thermal conductivity (κ) linearly increased up to ∼77% at 300 K with increasing temperature. We theoretically analyze and explain the high contribution of electronic component of thermal conductivity towards the total thermal conductivity of the film by a modified Callaway model. Further, we find the theoretical model predictions to correspond well with the experimental results.

Long-term effects of an intracavitary treatment with californium-252 on normal tissue

International Nuclear Information System (INIS)

Sullivan, M.F.; Beamer, J.L.; Mahony, T.D.; Cross, F.T.; Lund, J.E.; Endres, G.W.R.

1976-01-01

About one hundred fifty swine were exposed to either radium-226 or californium-252 sources in the uterine cervix to determine an RBE for both acute and long-term effects. That value for early changes in the tissues at risk in the treatment of cervical cancer was between 6.2 and 6.8. The incidence of complications increased with time after exposure, especially among animals treated with 252 Cf. Analysis of rectal injury showed that ulceration occurred frequently within a year postexposure at doses between 1600 and 2400 rad calculated at 2 cm lateral to the source midline. Fat necrosis and smooth muscle atrophy, resulting in a local rectal stricture, were delayed changes observed in some animals. The lower ureter was the site for a greater frequency of complications than the GI tract. Ureteral stricture often occurred at doses of 1200 rad from 252 Cf and 7000 rad from 226 Ra. Observation of delayed effects in the uterine-cervix in animals held up to 4 years postexposure indicate that the RBE for 252 Cf may be increased to a value as high as 18, while repair may have even decreased it to about 5.6 in the rectum. Fifty swine are still being observed for long-term effects after doses above 800 rad from 252 Cf and 5000 rad from 226 Ra

Processing and characterization of new oxy-sulfo-telluride glasses in the Ge-Sb-Te-S-O system

International Nuclear Information System (INIS)

Smith, C.; Jackson, J.; Petit, L.; Rivero-Baleine, C.; Richardson, K.

2010-01-01

New oxy-sulfo-telluride glasses have been prepared in the Ge-Sb-Te-S-O system employing a two-step melting process which involves the processing of a chalcogenide glass (ChG) and subsequent melting with TeO 2 or Sb 2 O 3 . The progressive incorporation of O at the expense of S was found to increase the density and the glass transition temperature and to decrease the molar volume of the investigated oxy-sulfo-telluride glasses. We also observed a shift of the vis-NIR cut-off wavelength to longer wavelength probably due to changes in Sb coordination within the glass matrix and overall matrix polarizability. Using Raman spectroscopy, correlations have been shown between the formation of Ge- and Sb-based oxysulfide structural units and the S/O ratio. Lastly, two glasses with similar composition (Ge 20 Sb 6 S 64 Te 3 O 7 ) processed by melting the Ge 23 Sb 7 S 70 glass with TeO 2 or the Ge 23 Sb 2 S 72 Te 4 glass with Sb 2 O 3 were found to have slightly different physical, thermal, optical and structural properties. These changes are thought to result mainly from the higher moisture content and sensitivity of the TeO 2 starting materials as compared to that of the Sb 2 O 3 . - Graphical abstract: In this paper, we discuss our most recent findings on the processing and characterization of new ChG glasses prepared with small levels of Te, melted either with TeO 2 or Sb 2 O 3 powders. We explain how these new oxy-sulfo-telluride glasses are prepared and we correlate the physical, thermal and optical properties of the investigated glasses to the structure changes induced by the addition of oxygen in the Ge-Sb-S-Te glass network.

Computational analysis of interfacial attachment kinetics and transport phenomena during liquid phase epitaxy of mercury cadmium telluride

Energy Technology Data Exchange (ETDEWEB)

Rasin, Igal; Brandon, Simon [Dept. of Chemical Engineering, Technion, Haifa 32000 (Israel); Ben Dov, Anne; Grimberg, Ilana; Klin, Olga; Weiss, Eliezer [SCD-Semi-Conductor Devices, P.O. Box 2250/99, Haifa 31021 (Israel)

2010-07-01

Deposition of mercury cadmium telluride (MCT) thin films, on lattice matched cadmium zinc telluride substrates, is often achieved via Liquid Phase Epitaxy (LPE). The yield and quality of these films, required for the production of infrared detector devices, is to a large extent limited by lack of knowledge regarding details of physical phenomena underlying the deposition process. Improving the understanding of these phenomena and their impact on the quality of the resultant films is therefore an important goal which can be achieved through relevant computational and/or experimental studies. We present a combined computational and experimental effort aimed at elucidating physical phenomena underlying the LPE of MCT via a slider growth process. The focus of the presentation will be results generated by a time-dependent three-dimensional model of mass transport, fluid flow, and interfacial attachment kinetics, which we have developed and applied in the analysis of this LPE process. These results, combined with experimental analyses, lead to an improved understanding of the role of different transport and kinetic phenomena underlying this growth process.

Formation of solid solutions on the boundary of zinc oxidezinc telluride heterojunction

International Nuclear Information System (INIS)

Tsurkan, A.E.; Buzhor, L.V.

1987-01-01

Distribution of ZnO x Te 1-x alloy composition on the interface of zinc oxide-zinc telluride heterojunction depending on the production conditions is investigated. A regularity in the formation of an extended area with constant alloy composition is detected. The regularity is explained by the fact that electric Peltier field conditioned by contact of two heterogeneous semiconductors participates in the solid solution formation process. Peltier field levels off the composition at the end length section. So, a possibility of creating a section with the assigned minor thickness alloy constant composition controlled in the interface of heterojunction occurs

Feasibility and market potential of protein determination of wheat using californium-252

International Nuclear Information System (INIS)

Roberts, T.C. Jr.; Eckhoff, N.D.; Clack, R.W.; Roberts, T.C. Sr.

1976-01-01

To evaluate the feasibility of protein determination by capture gamma-ray analysis using californium-252 neutrons, an in-situ protein analysis system for use by grain handlers has been examined. Three 227 kilogram (approximately) lots of wheat were used to determine the amount of nitrogen present. Protein analyses by the Kjeldahl method were obtained from samples taken before and after the capture gamma-ray analyses. The 5.267-MeV gamma-ray was selected for use in this study as a compromise between efficiency and interference from other elements. The associated counting equipment was a multichannel analyzer with pulse shaping electronic and analysis computing equipment. A linear regression program was used to compare the regions of interest to the Kjeldahl protein averages. The counts composing each peak were summed and normalized using the total count of the hydrogen peak. The normalized nitrogen percentages indicate a significant correlation between the spectral regions and the Kjeldahl analyses. To a first approximation, the value of wheat is the wheat protein. At the present time, protein testing of wheat is destructive, cumbersome, and time-consuming as compared to the potential for capture gamma-ray analysis testing. Assuming that such a protein analysis unit can analyze 42 tonne of wheat per hour, over 120 units would be needed to monitor one-half the U.S. annual wheat production. A 0.5% improvement in processor realizations and grain throughput value of $167.00 per tonne will result in a projected savings of $150,000 per year per unit

Effect of thallium impurity on hole scattering in lead telluride

International Nuclear Information System (INIS)

Kajdanov, V.I.; Nemov, S.A.

1981-01-01

Hole mobility in PbTe monocrystalline specimens in the temperature range from 4.2 to 300 K has been investigated. Detected is a sharp increase in scattering cross section of light and heavy holes in the specimens having the Hall hole concentration p approximately (5+-9)x10 19 cm -3 explained by resonant scattering into a band of quasilocal states of thallium located lower than the ceiling of heavy carrier zone by 0.01+-0.01 eV. Very large differences in resonant scattering of current carriers into the quasilocal states of In and Tl in PbTe result from the inertial polarizability of a crystal. The same mechanism is used to explain long-lived relaxation of zone electron concentration in lead telluride and Pbsub(1-x)Snsub(x)Te doped with indium [ru

Theoretical study of bismuth-doped cadmium telluride

Science.gov (United States)

Menendez-Proupin, E.; Rios-Gonzalez, J. A.; Pena, J. L.

Cadmium telluride heavily doped with bismuth has been proposed as an absorber with an intermediate band for solar cells. Increase in the photocurrent has been shown recently, although the overall cell efficiency has not improved. In this work, we study the electronic structure and the formation energies of the defects associated to bismuth impurities. We have performed electronic structure calculations within generalized density functional theory, using the exchange-correlation functional HSE(w) , where the range-separation parameter w has been tuned to reproduce the CdTe bandgap. Improving upon previous reports, we have included the spin-orbit interaction, which modifies the structure of the valence band and the energy levels of bismuth. We have found that interstitial Bi (Bii) tends to occupy Cd vacancies, cadmium substitution (BiCd) creates single donor level, while tellurium substitution (BiTe) is a shallow single acceptor. We investigate the interaction between these point defects and how can they be combined to create a partially filled intermediate band. Supported by FONDECYT Grant 1130437, CONACYT-SENER SUSTENTABILIDAD ENERGETICA/project CeMIE-Sol PY-207450/25 and PY-207450/26. JARG acknowledges CONACYT fellowship for research visit. Powered@NLHPC (ECM-02).

Novel aspects of application of cadmium telluride quantum dots nanostructures in radiation oncology

Science.gov (United States)

Fazaeli, Yousef; Zare, Hakimeh; Karimi, Shokufeh; Rahighi, Reza; Feizi, Shahzad

2017-08-01

In the last two decades, quantum dots nanomaterials have garnered a great deal of scientific interest because of their unique properties. Quantum dots (QDs) are inorganic fluorescent nanocrystals in the size range between 1 and 20 nm. Due to their structural properties, they possess distinctive properties and behave in different way from crystals in macro scale, in many branches of human life. Cadmium telluride quantum dots (CdTe QDs) were labeled with 68Ga radio nuclide for fast in vivo targeting and coincidence imaging of tumors. Using instant paper chromatography, the physicochemical properties of the Cadmium telluride quantum dots labeled with 68Ga NPs (68Ga@ CdTe QDs) were found high enough stable in organic phases, e.g., a human serum, to be reliably used in bioapplications. In vivo biodistribution of the 68Ga@ CdTe QDs nanoconposite was investigated in rats bearing fibro sarcoma tumor after various post-injection periods of time. The 68Ga NPs exhibited a rapid as well as high tumor uptake in a very short period of time (less than 10 min), resulting in an efficient tumor targeting/imaging agent. Meantime, the low lipophilicity of the 68Ga NPs caused to their fast excretion throughout the body by kidneys (as also confirmed by the urinary tract). Because of the short half-life of 68Ga radionuclide, the 68Ga@ CdTe QDs with an excellent tumor targeting/imaging and fast washing out from the body can be suggested as one of the most effective and promising nanomaterials in nanotechnology-based cancer diagnosis and therapy.

Manganese determination om minerals by activation analysis, using the californium-252 as a neutron source

International Nuclear Information System (INIS)

Cardoso, Antonio

1976-01-01

Neutron Activation Analysis, using a Californium-252 neutron source, has been applied for the determination of manganese in ores such as pyrolusite, rodonite (manganese silicate)' and blending used in dry-batteries The favorable nuclear properties of manganese, such as high thermal neutron cross-section for the reaction 55 Mn (n.gamma) 56 Mn, high concentration of manganese in the matrix and short half - life of 56 Mn, are an ideal combination for non-destructive analysis of manganese in ores. Samples and standards of manganese dioxide were irradiated for about 20 minutes, followed by a 4 to 15 minutes decay and counted in a single channel pulse-height discrimination using a NaI(Tl) scintillation detector. Counting time was equal to 10 minutes. The interference of nuclear reactions 56 Fe(n,p) 56 Mn and 59 Co (n, α) 56 were studied, as well as problems in connection with neutron shadowing during irradiation, gamma-rays attenuation during counting and influence of granulometry of samples. One sample,was also analysed by wet-chemical method (sodium bismuthate) in order to compare results. As a whole, i t was shown that the analytical method of neutron activation for manganese in ores and blending, is a method simple, rapid and with good precision and accuracy. (author)

The use of cadmium telluride γ spectrometers in monitoring activity deposited in nuclear power stations

International Nuclear Information System (INIS)

Jones, L.T.

1977-01-01

The ability to inspect and test key components and when necessary repair or replace them is a significant factor in the safety case submitted before consent is given for construction of a nuclear reactor. A knowledge of the probable rate of deposition and isotopic composition of radioactive contamination in these areas is necessary and since it is not always practicable to take samples away to the laboratory for analysis, direct gamma ray spectroscopy in the contaminated environment is sometimes used. The experience of direct monitoring with a cadmium telluride spectrometer in two such reactor situations is reported. In the first situation, a remotely cooled intrinsic Germanium spectrometer was used in equivalent positions and spectra from both systems are presented. The relative merits of the two systems are discussed. In the second situation, measurements were made in an environment at 70 deg C in radiation levels of 10Rh -1 . An improvised cooling system was used to maintain the Cadmium Telluride at about 20 deg C and Pile-up Rejection was used to enable count rates of about 10 5 s -1 to be handled. It is noted that the usually quoted detector parameters, resolution and crystal volume, are not necessarily the most important in practical spectrometry of mixed isotopes. As with germanium detectors, the most useful parameter is probably the Peak-to-Compton ratio

Tiny optical fiber temperature sensor based on temperature-dependent refractive index of zinc telluride film

Science.gov (United States)

Bian, Qiang; Song, Zhangqi; Song, Dongyu; Zhang, Xueliang; Li, Bingsheng; Yu, Yang; Chen, Yuzhong

2018-03-01

The temperature-dependent refractive index of zinc telluride film can be used to develop a tiny, low cost and film-coated optical fiber temperature sensor. Pulse reference-based compensation technique is used to largely reduce the background noise which makes it possible to detect the minor reflectivity change of the film in different temperatures. The temperature sensitivity is 0.0034dB/° and the background noise is measured to be 0.0005dB, so the resolution can achieve 0.2°.

Cadmium zinc telluride as a mid-infrared variable retarder

Science.gov (United States)

FitzGerald, William; Taherion, Saeid; Kumar, F. Joseph; Giles, David; Hore, Dennis

2018-04-01

The electro-optic behavior of cadmium zinc telluride is examined in the mid-infrared region between 3 and 11 μm, for applied DC field strengths of up to 106 V/m. The measurements performed here include full characterization of the polarization state of the transmitted light by means of the Stokes vector. We demonstrate the suitability of this material for DC variable retarder applications such as those achieved by quarter- or half-wave retardation. A comparison of two different metallic coatings for electrodes, gold and indium, reveals important differences in performance that are attributed to the homogeneity of the field through the bulk of the crystal. We illustrate that, in the case of both metals, the same electro-optic coefficients are measured, but regions of higher and lower retardation result in significant depolarization in the case of gold. Such depolarization may adversely affect the contrast ratio in a light valve, or increase the voltage necessary for the operation of an arbitrary polarization state generator.

Study on thermal annealing of cadmium zinc telluride (CZT) crystals

International Nuclear Information System (INIS)

Yang, G.; Bolotnikov, A.E.; Fochuk, P.M.; Camarda, G.S.; Cui, Y.; Hossain, A.; Kim, K.; Horace, J.; McCall, B.; Gul, R.; Xu, L.; Kopach, O.V.; James, R.B.

2010-01-01

Cadmium Zinc Telluride (CZT) has attracted increasing interest with its promising potential as a room-temperature nuclear-radiation-detector material. However, different defects in CZT crystals, especially Te inclusions and dislocations, can degrade the performance of CZT detectors. Post-growth annealing is a good approach potentially to eliminate the deleterious influence of these defects. At Brookhaven National Laboratory (BNL), we built up different facilities for investigating post-growth annealing of CZT. Here, we report our latest experimental results. Cd-vapor annealing reduces the density of Te inclusions, while large temperature gradient promotes the migration of small-size Te inclusions. Simultaneously, the annealing lowers the density of dislocations. However, only-Cd-vapor annealing decreases the resistivity, possibly reflecting the introduction of extra Cd in the lattice. Subsequent Te-vapor annealing is needed to ensure the recovery of the resistivity after removing the Te inclusions.

First operation of cesium telluride photocathodes in the TTF injector RF gun

CERN Document Server

Sertore, D; Flöttmann, K; Stephan, F; Zapfe, K; Michelato, P

2000-01-01

During the run 1998/1999 a new injector based on a laser-driven RF gun was brought in operation at the TESLA Test Facility (TTF) linac at DESY, in order to produce the beam structure and quality required either by TeV collider and SASE FEL experiments. High quantum efficiency cesium telluride photocathodes, prepared at Milano and transferred to DESY, have been successfully operated in the RF gun. A bunch charge of 50 nC, only limited by space charge effects, was achieved. The photocathodes have shown an operative lifetime of several months. A new cathode surface finishing has showed a promising decrease of the photocathode dark current. Measurements of dark current, quantum efficiency and lifetime are reported.

Novel aspects of application of cadmium telluride quantum dots nanostructures in radiation oncology

Energy Technology Data Exchange (ETDEWEB)

Fazaeli, Yousef; Feizi, Shahzad [Nuclear Science and Technology Research Institute (NSTRI), Radiation Application Research School, Karaj (Iran, Islamic Republic of); Zare, Hakimeh; Karimi, Shokufeh [Yazd University, Department of Physics, Yazd (Iran, Islamic Republic of); Rahighi, Reza [Sharif University of Technology, Department of Physics, Tehran (Iran, Islamic Republic of)

2017-08-15

In the last two decades, quantum dots nanomaterials have garnered a great deal of scientific interest because of their unique properties. Quantum dots (QDs) are inorganic fluorescent nanocrystals in the size range between 1 and 20 nm. Due to their structural properties, they possess distinctive properties and behave in different way from crystals in macro scale, in many branches of human life. Cadmium telluride quantum dots (CdTe QDs) were labeled with {sup 68}Ga radio nuclide for fast in vivo targeting and coincidence imaging of tumors. Using instant paper chromatography, the physicochemical properties of the Cadmium telluride quantum dots labeled with {sup 68}Ga NPs ({sup 68}Ga rate at CdTe QDs) were found high enough stable in organic phases, e.g., a human serum, to be reliably used in bioapplications. In vivo biodistribution of the {sup 68}Ga rate at CdTe QDs nanoconposite was investigated in rats bearing fibro sarcoma tumor after various post-injection periods of time. The {sup 68}Ga NPs exhibited a rapid as well as high tumor uptake in a very short period of time (less than 10 min), resulting in an efficient tumor targeting/imaging agent. Meantime, the low lipophilicity of the {sup 68}Ga NPs caused to their fast excretion throughout the body by kidneys (as also confirmed by the urinary tract). Because of the short half-life of {sup 68}Ga radionuclide, the {sup 68}Ga rate at CdTe QDs with an excellent tumor targeting/imaging and fast washing out from the body can be suggested as one of the most effective and promising nanomaterials in nanotechnology-based cancer diagnosis and therapy. (orig.)

A cadmium-zinc-telluride crystal array spectrometer

International Nuclear Information System (INIS)

McHugh, H. R.; Quam, W.; DeVore, T.; Vogle, R.; Weslowski, J.

2003-01-01

This paper describes a gamma detector employing an array of eight cadmium-zinc-telluride (CZT) crystals configured as a high resolution gamma ray spectrometer. This detector is part of a more complex instrument that identifies the isotope,displays this information, and records the gamma spectrum. Various alarms and other operator features are incorporated in this battery operated rugged instrument. The CZT detector is the key component of this instrument and will be described in detail in this paper. We have made extensive spectral measurements of the usual laboratory gamma sources, common medical isotopes, and various Special Nuclear Materials (SNM) with this detector. Some of these data will be presented as spectra. We will also present energy resolution and detection efficiency for the basic 8-crystal array. Additional data will also be presented for a 32-crystal array. The basic 8-crystal array development was completed two years ago, and the system electronic design has been imp roved recently. This has resulted in significantly improved noise performance. We expect to have a much smaller detector package, using 8 crystals, in a few months. This package will use flip-chip packaging to reduce the electronics physical size by a factor of 5

Precision timing detectors with cadmium-telluride sensor

Science.gov (United States)

Bornheim, A.; Pena, C.; Spiropulu, M.; Xie, S.; Zhang, Z.

2017-09-01

Precision timing detectors for high energy physics experiments with temporal resolutions of a few 10 ps are of pivotal importance to master the challenges posed by the highest energy particle accelerators such as the LHC. Calorimetric timing measurements have been a focus of recent research, enabled by exploiting the temporal coherence of electromagnetic showers. Scintillating crystals with high light yield as well as silicon sensors are viable sensitive materials for sampling calorimeters. Silicon sensors have very high efficiency for charged particles. However, their sensitivity to photons, which comprise a large fraction of the electromagnetic shower, is limited. To enhance the efficiency of detecting photons, materials with higher atomic numbers than silicon are preferable. In this paper we present test beam measurements with a Cadmium-Telluride (CdTe) sensor as the active element of a secondary emission calorimeter with focus on the timing performance of the detector. A Schottky type CdTe sensor with an active area of 1cm2 and a thickness of 1 mm is used in an arrangement with tungsten and lead absorbers. Measurements are performed with electron beams in the energy range from 2 GeV to 200 GeV. A timing resolution of 20 ps is achieved under the best conditions.

Diaroyl Tellurides: Synthesis, Structure and NBO Analysis of (2-MeOC6H4CO2Te – Comparison with Its Sulfur and Selenium Isologues. The First Observation of [MgBr][R(C=TeO] Salts

Directory of Open Access Journals (Sweden)

Fumio Ando

2009-07-01

Full Text Available A series of aromatic diacyl tellurides were prepared in moderate to good yields by the reactions of sodium orpotassium arenecarbotelluroates with acyl chlorides in acetonitrile. X-ray structure analyses and theoretical calculations of 2-methoxybenzoic anhydride and bis(2-methoxybenzoyl sulfide, selenide and telluride were carried out. The two 2-MeOC6H4CO moieties of bis(2-methoxybenzoyl telluride are nearly planar and the two methoxy oxygen atoms intramolecularly coordinate to the central tellurium atom from both side of C(11-Te(11-C(22 plane. In contrast, the oxygen and sulfur isologues (2-MeOC6H4CO2E (E = O, S, show that one of the two methoxy oxygen atoms contacts with the oxygen atom of the carbonyl group connected to the same benzene ring. The structure of di(2-methoxybenzoyl selenide which was obtained by MO calculation resembles that of tellurium isologues rather than the corresponding oxygen and sulfur isologues. The reactions of di(aroyl tellurides with Grignard reagents lead to the formation of tellurocarboxylato magnesium complexes [MgBr][R(C=TeO].

Effect of ball milling time on thermoelectric properties of bismuth telluride nanomaterials

Science.gov (United States)

Khade, Poonam; Bagwaiya, Toshi; Bhattacharaya, Shovit; Singh, Ajay; Jha, Purushottam; Shelke, Vilas

2018-04-01

The effect of different milling time on thermoelectric properties of bismuth telluride (Bi2Te3) was investigated. The nanomaterial was prepared by varying the ball milling time and followed by hot press sintering. The crystal structure and phase formation were verified by X-ray diffraction and Raman Spectroscopy. The experimental results show that electrical conductivity increases whereas thermal conductivity decreases with increasing milling time. The negative sign of seebeck coefficient indicate the n-type nature with majority charge carriers of electrons. A maximum figure of merit about 0.55 is achieved for l5hr ball milled Bi2Te3 sample. The present study demonstrates the simple and cost-effective method for synthesis of Bi2Te3 thermoelectric material at large scale thermoelectric applications.

Niobium and zirconium telluride thin films prepared by sputtering

International Nuclear Information System (INIS)

Kassem, M.; Pailharey, D.; Mathey, Y.

2000-01-01

A versatile procedure of sputter deposition, well adapted for getting a large of Te/M ratios (with M = Zr or Nb), has led to the synthesis of several highly anisotropic zirconium and niobium poly tellurides in thin film form. Upon tuning the two key parameters of the process, i.e., the Te percentage in the target and the substrate temperature during the deposition, preparation of systems ranging from ZrTe 0 .72 to ZrTe 6 .7, on the one hand, and from NbTe 1 .28 to NbTe 7 .84, on the other, has been achieved. Besides their amorphous or crystalline (with or without preferential orientations) behavior and their relationship to known structural types, the most striking feature of these films is their large departure from the stoichiometry of the bulk Mte x reference compounds. This peculiarity, together with the possible changes of composition under annealing, are described and interpreted in terms of variable of Te and M atoms trapped or intercalated within the parent structures. (author)

Selective and low temperature transition metal intercalation in layered tellurides

Science.gov (United States)

Yajima, Takeshi; Koshiko, Masaki; Zhang, Yaoqing; Oguchi, Tamio; Yu, Wen; Kato, Daichi; Kobayashi, Yoji; Orikasa, Yuki; Yamamoto, Takafumi; Uchimoto, Yoshiharu; Green, Mark A.; Kageyama, Hiroshi

2016-01-01

Layered materials embrace rich intercalation reactions to accommodate high concentrations of foreign species within their structures, and find many applications spanning from energy storage, ion exchange to secondary batteries. Light alkali metals are generally most easily intercalated due to their light mass, high charge/volume ratio and in many cases strong reducing properties. An evolving area of materials chemistry, however, is to capture metals selectively, which is of technological and environmental significance but rather unexplored. Here we show that the layered telluride T2PTe2 (T=Ti, Zr) displays exclusive insertion of transition metals (for example, Cd, Zn) as opposed to alkali cations, with tetrahedral coordination preference to tellurium. Interestingly, the intercalation reactions proceed in solid state and at surprisingly low temperatures (for example, 80 °C for cadmium in Ti2PTe2). The current method of controlling selectivity provides opportunities in the search for new materials for various applications that used to be possible only in a liquid. PMID:27966540

Ag-tellurides at the site Treibolc near the village Hodrusa-Hamre; Ag-teluridy na lokalite Treibolc pri obci Hodrusa-Hamre

Energy Technology Data Exchange (ETDEWEB)

Kozak, J [Univerzita Komenskeho v Bratislave, Prirodovedecka fakulta, Katedra mineralogie a petrologie, 84215 Bratislava (Slovakia)

2012-04-25

Ag-tellurides were described in association with galenite, sphalerite, chalcopyrite and bornite samples during examining hydrothermal mineralization of Stiavnica stratovolcano (Hodrusa-Hamre settlement) in heavily silicified sediments of Permian age. They were found and confirmed by WDS analysis. Their presence on the site is very unique with no economic use. Paragenesis originated at 250-270 grad C in the presence of fluid and zero salinity. (authors)

Structural, Mechanical and Thermodynamic Properties under Pressure Effect of Rubidium Telluride: First Principle Calculations

Directory of Open Access Journals (Sweden)

Bidai K.

2017-06-01

Full Text Available First-principles density functional theory calculations have been performed to investigate the structural, elastic and thermodynamic properties of rubidium telluride in cubic anti-fluorite (anti-CaF2-type structure. The calculated ground-state properties of Rb2Te compound such as equilibrium lattice parameter and bulk moduli are investigated by generalized gradient approximation (GGA-PBE that are based on the optimization of total energy. The elastic constants, Young’s and shear modulus, Poisson ratio, have also been calculated. Our results are in reasonable agreement with the available theoretical and experimental data. The pressure dependence of elastic constant and thermodynamic quantities under high pressure are also calculated and discussed.

Large-scale synthesis of lead telluride (PbTe) nanotube-based nanocomposites with tunable morphology, crystallinity and thermoelectric properties

Science.gov (United States)

Park, Kee-Ryung; Cho, Hong-Baek; Song, Yoseb; Kim, Seil; Kwon, Young-Tae; Ryu, Seung Han; Lim, Jae-Hong; Lee, Woo-Jin; Choa, Yong-Ho

2018-04-01

A few millimeter-long lead telluride (PbTe) hollow nanofibers with thermoelectric properties was synthesized for the first time with high through manner via three-step sequential process of electrospinning, electrodeposition and cationic exchange reaction. As-synthesized electrospun Ag nanofibers with ultra-long aspect ratio of 10,000 were Te electrodeposited to obtain silver telluride nanotubes and underwent cationic exchange reaction in Pb(NO3)2 solution to obtain polycrystalline PbTe nanotubes with average diameter of 100 nm with 20 nm of wall thickness. Variation of the Ag-to-Pb ratio in the AgxTey-PbTe nanocomposites during the cationic exchange reaction enabled to control the thermoelectric properties of resulting 1D hollow nanofibers. The diameter of Ag nanofiber is the key factor to determine the final dimension of the PbTe nanotubes in the topotactic transformation and the content of Ag ion leads to the enhancement of thermoelectric properties in the AgxTey-PbTe nanocomposites. The synthesized 1D nanocomposite mats showed the highest value of Seebeck coefficient of 433 μV/K (at 300 K) when the remained Ag content was 30%, while the power factor reached highest to 0.567 μW/mK2 for the pure PbTe nanotubes. The enhancement of thermoelectric properties and the composite crystallinity are elucidated with relation to Ag contents in the resulting 1D nanocomposites.

Preliminary uranium enrichment analysis results using cadmium zinc telluride detectors

International Nuclear Information System (INIS)

Lavietes, A.D.; McQuaid, J.H.; Paulus, T.J.

1995-01-01

Lawrence Livermore National Laboratory (LLNL) and EG ampersand G ORTEC have jointly developed a portable ambient-temperature detection system that can be used in a number of application scenarios. The detection system uses a planar cadmium zinc telluride (CZT) detector with custom-designed detector support electronics developed at LLNL and is based on the recently released MicroNOMAD multichannel analyzer (MCA) produced by ORTEC. Spectral analysis is performed using software developed at LLNL that was originally designed for use with high-purity germanium (HPGe) detector systems. In one application, the CZT detection system determines uranium enrichments ranging from less than 3% to over 75% to within accuracies of 20%. The analysis was performed using sample sizes of 200 g or larger and acquisition times of 30 min. The authors have demonstrated the capabilities of this system by analyzing the spectra gathered by the CZT detection system from uranium sources of several enrichments. These experiments demonstrate that current CZT detectors can, in some cases, approach performance criteria that were previously the exclusive domain of larger HPGe detector systems

Development of a cadmium telluride pixel detector for astrophysical applications

Science.gov (United States)

Miyasaka, Hiromasa; Harrison, Fiona A.; Cook, Walter R.; Mao, Peter H.; Rana, Vikram R.; Ishikawa, Shin-Nosuke; Ushio, Masayoshi; Aono, Hiroyuki; Watanabe, Shin; Sato, Goro; Kokubun, Motohide; Takahashi, Tadayuki

2009-08-01

We are developing imaging Cadmium Telluride (CdTe) pixel detectors optimized for astrophysical hard X-ray applications. Our hybrid detector consist of a CdTe crystal 1mm thick and 2cm × 2cm in area with segmented anode contacts directly bonded to a custom low-noise application specific integrated circuit (ASIC). The CdTe sensor, fabricated by ACRORAD (Okinawa, Japan), has Schottky blocking contacts on a 605 micron pitch in a 32 × 32 array, providing low leakage current and enabling readout of the anode side. The detector is bonded using epoxy-gold stud interconnects to a custom low noise, low power ASIC circuit developed by Caltech's Space Radiation Laboratory. We have achieved very good energy resolution over a wide energy range (0.62keV FWHM @ 60keV, 10.8keV FWHM @ 662keV). We observe polarization effects at room temperature, but they are suppressed if we operate the detector at or below 0°C degree. These detectors have potential application for future missions such as the International X-ray Observatory (IXO).

Heart imaging by cadmium telluride gamma camera European Program 'BIOMED' consortium

CERN Document Server

Scheiber, C; Chambron, J; Prat, V; Kazandjan, A; Jahnke, A; Matz, R; Thomas, S; Warren, S; Hage-Hali, M; Regal, R; Siffert, P; Karman, M

1999-01-01

Cadmium telluride semiconductor detectors (CdTe) operating at room temperature are attractive for medical imaging because of their good energy resolution providing excellent spatial and contrast resolution. The compactness of the detection system allows the building of small light camera heads which can be used for bedside imaging. A mobile pixellated gamma camera based on 2304 CdTe (pixel size: 3x3 mm, field of view: 15 cmx15 cm) has been designed for cardiac imaging. A dedicated 16-channel integrated circuit has also been designed. The acquisition hardware is fully programmable (DSP card, personal computer-based system). Analytical calculations have shown that a commercial parallel hole collimator will fit the efficiency/resolution requirements for cardiac applications. Monte-Carlo simulations predict that the Moire effect can be reduced by a 15 deg. tilt of the collimator with respect to the detector grid. A 16x16 CdTe module has been built for the preliminary physical tests. The energy resolution was 6.16...

Laser Photolysis and Thermolysis of Organic Selenides and Tellurides for Chemical Gas-phase Deposition of Nanostructured Materials

Directory of Open Access Journals (Sweden)

Josef Pola

2009-03-01

Full Text Available Laser radiation-induced decomposition of gaseous organic selenides and tellurides resulting in chemical deposition of nanostructured materials on cold surfaces is reviewed with regard to the mechanism of the gas-phase decomposition and properties of the deposited materials. The laser photolysis and laser thermolysis of the Se and Te precursors leading to chalcogen deposition can also serve as a useful approach to nanostructured chalcogen composites and IVA group (Si, Ge, Sn element chalcogenides provided that it is carried out simultaneously with laser photolysis or thermolysis of polymer and IVA group element precursor.

Long-term effects of an intracavitary treatment with californium-252 on normal tissue. [Swine, /sup 226/Ra

Energy Technology Data Exchange (ETDEWEB)

Sullivan, M.F.; Beamer, J.L.; Mahony, T.D.; Cross, F.T.; Lund, J.E.; Endres, G.W.R.

1976-01-01

About one hundred fifty swine were exposed to either radium-226 or californium-252 sources in the uterine cervix to determine an RBE for both acute and long-term effects. That value for early changes in the tissues at risk in the treatment of cervical cancer was between 6.2 and 6.8. The incidence of complications increased with time after exposure, especially among animals treated with /sup 252/Cf. Analysis of rectal injury showed that ulceration occurred frequently within a year postexposure at doses between 1600 and 2400 rad calculated at 2 cm lateral to the source midline. Fat necrosis and smooth muscle atrophy, resulting in a local rectal stricture, were delayed changes observed in some animals. The lower ureter was the site for a greater frequency of complications than the GI tract. Ureteral stricture often occurred at doses of 1200 rad from /sup 252/Cf and 7000 rad from /sup 226/Ra. Observation of delayed effects in the uterine-cervix in animals held up to 4 years postexposure indicate that the RBE for /sup 252/Cf may be increased to a value as high as 18, while repair may have even decreased it to about 5.6 in the rectum. Fifty swine are still being observed for long-term effects after doses above 800 rad from /sup 252/Cf and 5000 rad from /sup 226/Ra.

Fast and efficient charge breeding of the Californium rare isotope breeder upgrade electron beam ion source

International Nuclear Information System (INIS)

Ostroumov, P. N.; Barcikowski, A.; Dickerson, C. A.; Perry, A.; Sharamentov, S. I.; Vondrasek, R. C.; Zinkann, G. P.; Pikin, A. I.

2015-01-01

The Electron Beam Ion Source (EBIS), developed to breed Californium Rare Isotope Breeder Upgrade (CARIBU) radioactive beams at Argonne Tandem Linac Accelerator System (ATLAS), is being tested off-line. A unique property of the EBIS is a combination of short breeding times, high repetition rates, and a large acceptance. Overall, we have implemented many innovative features during the design and construction of the CARIBU EBIS as compared to the existing EBIS breeders. The off-line charge breeding tests are being performed using a surface ionization source that produces singly charged cesium ions. The main goal of the off-line commissioning is to demonstrate stable operation of the EBIS at a 10 Hz repetition rate and a breeding efficiency into single charge state higher than 15%. These goals have been successfully achieved and exceeded. We have measured (20% ± 0.7%) breeding efficiency into the single charge state of 28+ cesium ions with the breeding time of 28 ms. In general, the current CARIBU EBIS operational parameters can provide charge breeding of any ions in the full mass range of periodic table with high efficiency, short breeding times, and sufficiently low charge-to-mass ratio, 1/6.3 for the heaviest masses, for further acceleration in ATLAS. In this paper, we discuss the parameters of the EBIS and the charge breeding results in a pulsed injection mode with repetition rates up to 10 Hz

Enhanced thermoelectric properties of bismuth telluride-organic hybrid films via graphene doping

International Nuclear Information System (INIS)

Rahman, Airul Azha Abd; Umar, Akrajas Ali; Salleh, Muhamad Mat; Chen, Xiaomei; Oyama, Munetaka

2016-01-01

The thermoelectric properties of graphene-doped bismuth telluride-PEDOT:PSS-glycerol (hybrid) films were investigated. Prior to the study, p-type and n-type hybrid films were prepared by doping the PEDOT:PSS-glycerol with the p- and n-type bismuth telluride. Graphene-doped hybrid films were prepared by adding graphene particles of concentration ranging from 0.02 to 0.1 wt% into the hybrid films. Films of graphene-doped hybrid system were then prepared on a glass substrate using a spin-coating technique. It was found that the electrical conductivity of the hybrid films increases with the increasing of the graphene-dopant concentration and optimum at 0.08 wt% for both p- and n-type films, namely 400 and 195 S/cm, respectively. Further increasing in the concentration caused a decreasing in the electrical conductivity. Analysis of the thermoelectric properties of the films obtained that the p-type film exhibited significant improvement in its thermoelectric properties, where the thermoelectric properties increased with the increasing of the doping concentration. Meanwhile, for the case of n-type film, graphene doping showed a negative effect to the thermoelectrical properties, where the thermoelectric properties decreased with the increasing of doping concentration. Seebeck coefficient (and power factor) for optimum p-type and n-type hybrid thin films, i.e., doped with 0.08 wt% of graphene, is 20 μV/K (and 160 μW m -1 K -2 ) and 10 μV/K (and 19.5 μW m -1 K -2 ), respectively. The obtained electrical conductivity and thermoelectric properties of graphene-doped hybrid film are interestingly several orders higher than the pristine hybrid films. A thermocouple device fabricated utilizing the p- and n-type graphene-doped hybrid films can generate an electric voltage as high as 2.2 mV under a temperature difference between the hot-side and the cold-side terminal as only low as 55 K. This is equivalent to the output power as high as 24.2 nW (for output load as high as 50

High pressure and doping effects on the Curie temperature in chromium telluride

International Nuclear Information System (INIS)

Grazhdankina, N.P.; Bersenev, Yu.S.

1976-01-01

Results of an experimental investigation of the effect of hydrostatic pressure (up to 12 kbars) on the Curie temperature Tsub(c) of solid CrTsub(1-x)Xsub(x) solutions (X=Se, Sb) are presented for x concentration values up to 0.5. The baric coefficients γ=Tsub(c)sup(-1)(dTsub(c)/dP) for all alloys investigated are negative. However the γ(x) dependence is determined by the X alloy component and correspondingly by the nature of the compression which may be either isotropic (X=Se) or anisotropic (X=Sb). Possible mechanisms of exchange spin coupling in the alloys investigated are discussed on the basis of the data obtained. It is concluded that two types of exchange interactions coexist in chromium telluride: indirect exchange of localized electrons via the anion and interaction between collectivized electrons in the narrow 3d band energy determines the Curie temperature

Charge sharing and charge loss in a cadmium-zinc-telluride fine-pixel detector array

International Nuclear Information System (INIS)

Gaskin, J.A.; Sharma, D.P.; Ramsey, B.D.

2003-01-01

Because of its high atomic number, room temperature operation, low noise, and high spatial resolution a cadmium-zinc-telluride multi-pixel detector is ideal for hard X-ray astrophysical observation. As part of on-going research at MSFC to develop multi-pixel CdZnTe detectors for this purpose, we have measured charge sharing and charge loss for a 4x4 (750 μm pitch), 1 mm thick pixel array and modeled these results using a Monte-Carlo simulation. This model was then used to predict the amount of charge sharing for a much finer pixel array (with a 300 μm pitch). Future work will enable us to compare the simulated results for the finer array to measured values

Neutron flux characterization of californium-252 Neutron Research Facility at the University of Texas - Pan American by nuclear analytical technique

Science.gov (United States)

Wahid, Kareem; Sanchez, Patrick; Hannan, Mohammad

2014-03-01

In the field of nuclear science, neutron flux is an intrinsic property of nuclear reaction facilities that is the basis for experimental irradiation calculations and analysis. In the Rio Grande Valley (Texas), the UTPA Neutron Research Facility (NRF) is currently the only neutron facility available for experimental research purposes. The facility is comprised of a 20-microgram californium-252 neutron source surrounded by a shielding cascade containing different irradiation cavities. Thermal and fast neutron flux values for the UTPA NRF have yet to be fully investigated and may be of particular interest to biomedical studies in low neutron dose applications. Though a variety of techniques exist for the characterization of neutron flux, neutron activation analysis (NAA) of metal and nonmetal foils is a commonly utilized experimental method because of its detection sensitivity and availability. The aim of our current investigation is to employ foil activation in the determination of neutron flux values for the UTPA NSRF for further research purposes. Neutron spectrum unfolding of the acquired experimental data via specialized software and subsequent comparison for consistency with computational models lends confidence to the results.

Acetic acid-confined synthesis of uniform three-dimensional (3D) bismuth telluride nanocrystals consisting of few-quintuple-layer nanoplatelets

KAUST Repository

Yuan, Qiang; Radar, Kelly; Hussain, Muhammad Mustafa

2011-01-01

High-selectivity, uniform three-dimensional (3D) flower-like bismuth telluride (Bi2Te3) nanocrystals consisting of few-quintuple-layer nanoplatelets with a thickness down to 4.5 nm were synthesized for the first time by a facile, one-pot polyol method with acetic acid as the structure-director. Micrometre-sized 2D films and honeycomb-like spheres can be obtained using the uniform 3D Bi2Te3 nanocrystals as building blocks. © The Royal Society of Chemistry 2011.

Reaction of 1-bromo-3-chloropropane with tellurium and dimethyl telluride in the system of hydrazine hydrate-alkali

International Nuclear Information System (INIS)

Russavskaya, N.V.; Levanova, E.P.; Sukhomazova, Eh.N.; Grabel'nykh, V.A.; Elaev, A.V.; Klyba, L.V.; Zhanchipova, E.R.; Albanov, A.I.; Korotaeva, I.M.; Toryashinova, D.S.D.; Korchevin, N.A.

2006-01-01

A synthesis of oligomeric substance of thiocol type, the poly(trimethyleneditelluride), from 1-bromo-3-chloropropane and elemental tellurium is performed using a hydrazine hydrate-alkali system. Reductive splitting of the tellurocol followed by alkylation with methyl iodide give rise to preparation of bis(methyltelluro)propane, which was synthesized also from dimethyl telluride and 1,3-dihalopropanes using the N 2 H 4 ·H 2 O/KOH system. The reaction products were characterized by elementary analysis, NMR, and IR spectra. Mass spectra of the synthesized low molecular weight organotellurium compounds are considered [ru

Polymorphic one-dimensional (N2H4)2ZnTe: soluble precursors for the formation of hexagonal or cubic zinc telluride.

Science.gov (United States)

Mitzi, David B

2005-10-03

Two hydrazine zinc(II) telluride polymorphs, (N2H4)2ZnTe, have been isolated, using ambient-temperature solution-based techniques, and the crystal structures determined: alpha-(N2H4)2ZnTe (1) [P21, a = 7.2157(4) Angstroms, b = 11.5439(6) Angstroms, c = 7.3909(4) Angstroms, beta = 101.296(1) degrees, Z = 4] and beta-(N2H4)2ZnTe (2) [Pn, a = 8.1301(5) Angstroms, b = 6.9580(5) Angstroms, c = 10.7380(7) Angstroms, beta = 91.703(1) degrees, Z = 4]. The zinc atoms in 1 and 2 are tetrahedrally bonded to two terminal hydrazine molecules and two bridging tellurium atoms, leading to the formation of extended one-dimensional (1-D) zinc telluride chains, with different chain conformations and packings distinguishing the two polymorphs. Thermal decomposition of (N2H4)2ZnTe first yields crystalline wurtzite (hexagonal) ZnTe at temperatures as low as 200 degrees C, followed by the more stable zinc blende (cubic) form at temperatures above 350 degrees C. The 1-D polymorphs are soluble in hydrazine and can be used as convenient precursors for the low-temperature solution processing of p-type ZnTe semiconducting films.

Test and evaluation of infrared detectors and arrays; Proceedings of the Meeting, Orlando, FL, Mar. 27-29, 1989

Science.gov (United States)

Hoke, Forney M.

Papers on the testing and evaluation of IR detectors and arrays are presented, covering topics such as a short wavelength IR test system, pulse height analysis, the use of an expert system for IR detector testing, low-background IR focal plane testing, electron beam testing, high performance silicide Schottky photodiodes, the SDI organization focal plane test program, the absorption cross section of arsenic in silicon, and long wavelength IR hybrids. Other topics include low background radiometric detector measurements, an ultralow background dewar for IR detector characterization studies, a computer assisted mosaic array test station, a configurable detector array test station, automated detector material characterization capabilities, and a test system for mercury cadmium telluride photoconductor arrays. Additional topics include ionization dosimetry measurements inside a dewar for linac electron and californium-252 neutron environments, a radiation test facility using a variable-flux electron beam source, automated visual inspection of IR focal plane arrays, a titanium cryostat for low temperature radiation effects studies, a low dose rate gamma test facility, and the test and evaluation of stability in IR staring focal plane arrays after nonuniformity correction.

Cadmium-Zinc-Telluride photon detector for epithermal neutron spectroscopy--pulse height response characterisation

International Nuclear Information System (INIS)

Tardocchi, M.; Pietropaolo, A.; Andreani, C.; Bracco, A.; D'Angelo, A.; Gorini, G.; Imberti, S.; Senesi, R.; Rhodes, N.J.; Schooneveld, E.M.

2004-01-01

The Resonance Detector Spectrometer was recently revised for neutron spectroscopic studies in the eV energy region. In this technique one makes use of a photon detector to record the gamma emission from analyser foils used as neutron-gamma converters. The pulse-height response of a Cadmium-Zinc-Telluride photon detector to neutron capture emission from 238 U and 197 Au analyser foils was characterised in the neutron energy range 1-200 eV. The experiment was performed on the VESUVIO spectrometer at the ISIS neutron-pulsed source. A biparametric data acquisition, specifically developed for these measurements, allowed the simultaneous measurements of both the neutron time of flight and γ pulse-height spectra. Through the analysis of the γ pulse-height spectra the main components of the signal associated with resonant and non-resonant neutron absorption were identified. It was also shown that, in principle, energy discrimination can be used to improve the signal to background ratio of the neutron time-of-flight measurement

Investigation of the electrochemical deposition of thick layers of cadmium telluride

International Nuclear Information System (INIS)

Rousset, J.

2007-04-01

This research thesis deals with the problem of electrochemical deposition of thick layers of cadmium telluride (CdTe) meeting the requirements of high energy radiation detection. The author first recalls the physicochemical properties of CdTe and the basic principles of radiology. He details the different criteria which define a material for X ray detection. He describes the experimental conditions, the nature and preparation of substrates, and the different electrochemical systems used in this research. He studies the impact of the applied potential on the material properties, and compares previously obtained results available in the literature with those obtained in the chosen pool conditions. He discusses the synthesis of CdTe thick layers for which different methods are tested: static in potential, static in intensity, pulsed. The coatings obtained with a given potential and then with a given current are investigated. Finally, the influence of a thermal treatment in presence or absence of a sintering agent on the morphology, the chemical composition, and the crystalline and electric properties of the deposited material is discussed, and the results of the behaviour under X rays of a electrodeposited layer are presented

Measurement and Modeling of Blocking Contacts for Cadmium Telluride Gamma Ray Detectors

Energy Technology Data Exchange (ETDEWEB)

Beck, Patrick R. [California Polytechnic State Univ. (CalPoly), San Luis Obispo, CA (United States)

2010-01-07

Gamma ray detectors are important in national security applications, medicine, and astronomy. Semiconductor materials with high density and atomic number, such as Cadmium Telluride (CdTe), offer a small device footprint, but their performance is limited by noise at room temperature; however, improved device design can decrease detector noise by reducing leakage current. This thesis characterizes and models two unique Schottky devices: one with an argon ion sputter etch before Schottky contact deposition and one without. Analysis of current versus voltage characteristics shows that thermionic emission alone does not describe these devices. This analysis points to reverse bias generation current or leakage through an inhomogeneous barrier. Modeling the devices in reverse bias with thermionic field emission and a leaky Schottky barrier yields good agreement with measurements. Also numerical modeling with a finite-element physics-based simulator suggests that reverse bias current is a combination of thermionic emission and generation. This thesis proposes further experiments to determine the correct model for reverse bias conduction. Understanding conduction mechanisms in these devices will help develop more reproducible contacts, reduce leakage current, and ultimately improve detector performance.

A potential method using Ge{iPrNC[N(SiMe_3)_2]NiPr}{sub 2}, (Et{sub 3}Si){sub 2}Te and anhydrous hydrazine for germanium tellurides

Energy Technology Data Exchange (ETDEWEB)

Du, Liyong; Du, Shulei; Ding, Yuqiang [School of Chemical and Material Engineering, Jiangnan University, Wuxi (China)

2017-12-29

A germanium(II)-guanidine derivative of formula Ge{iPrNC[N(SiMe_3)_2]NiPr}{sub 2} (1) was synthesized and characterized by {sup 1}H NMR, {sup 13}C NMR, elemental analysis, and X-ray diffraction method. Thermal property was also studied to identify its thermal stability and volatility. More importantly, compound 1 was synthesized to develop a new method for germanium tellurides, where anhydrous hydrazine was introduced to prompt the activity of germanium(II) guanidines (or derivatives) towards (Et{sub 3}Si){sub 2}Te. Solution reaction of compound 1, (Et{sub 3}Si){sub 2}Te, and anhydrous hydrazine was investigated to pre-identify the feasibility of this combination for ALD process. The EDS data of the black precipitate from this reaction verified the potential of this method to manufacture germanium tellurides. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Heavily doped GaAs:Te layers grown by MOVPE using diisopropyl telluride as a source

Energy Technology Data Exchange (ETDEWEB)

Daniltsev, V. M.; Demidov, E. V.; Drozdov, M. N.; Drozdov, Yu. N., E-mail: drozdyu@ipmras.ru; Kraev, S. A.; Surovegina, E. A.; Shashkin, V. I.; Yunin, P. A. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation)

2016-11-15

The capabilities of GaAs epitaxial layers extremely heavily doped with tellurium by metal-organic vapor-phase epitaxy using diisopropyl telluride as a source are studied. It is shown that tellurium incorporation into GaAs occurs to an atomic concentration of 10{sup 21} cm{sup –3} without appreciable diffusion and segregation effects. Good carrier concentrations (2 × 10{sup 19} cm{sup –3}) and specific contact resistances of non-alloyed ohmic contacts (1.7 × 10{sup –6} Ω cm{sup 2}) give grounds to use such layers to create non-alloyed ohmic contacts in electronic devices. A sharp decrease in the electrical activity of Te atoms, a decrease in the electron mobility, and an increase in the contact resistance at atomic concentrations above 2 × 10{sup 20} cm{sup –3} are detected.

Trace analysis in cadmium telluride by heavy ion induced X-ray emission and by SIMS

International Nuclear Information System (INIS)

Scharager, C.; Stuck, R.; Siffert, P.; Cailleret, J.; Heitz, Ch.; Lagarde, G.; Tenorio, D.

1979-01-01

The possibilities of using both selective heavy ion induced X-ray emission and secondary ion mass spectroscopy (SIMS), for the identification of impurities present at low concentrations in cadmium telluride are examined. The relative concentrations of the impurities along CdTe crystals have been determined by exciting the X-ray emission of the elements in several slices with Ar and Kr ions and by comparing the relative characteristic X-ray emission yields. As a consequence of the quasimolecular inner shell ionization mechanism in heavy ion-atom collisions, Ar and Kr ions allow a strong excitation of the main impurities seen by SIMS namely Si, Cl and Ge, As, with only a minor contribution of Cd and Te. From the changes of the concentrations of the various impurities along the crystal, informations about segregation coefficients and compensation can be obtained

Synthesis and characterization of low-valence actinide phosphide tellurides and ternary selenium-halide iridium complexes; Synthese und Charakterisierung niedervalenter Actinoidphosphidtelluride und ternaerer Selen-Halogenid-Komplexe des Iridiums

Energy Technology Data Exchange (ETDEWEB)

Stolze, Karoline

2016-04-07

The thesis on the synthesis and characterization of low-valence actinide phosphide tellurides and ternary selenium-halide iridium complexes includes two parts: a description of the experimental synthesis of UPTe and U2PTe2O and ThPTe and the synthesis of selenium-chloride iridium complexes and selenium-bromide iridium complexes. The characterization included X-ray diffraction and phase studies.

An additive approach to low temperature zero pressure sintering of bismuth antimony telluride thermoelectric materials

Science.gov (United States)

Catlin, Glenn C.; Tripathi, Rajesh; Nunes, Geoffrey; Lynch, Philip B.; Jones, Howard D.; Schmitt, Devin C.

2017-03-01

This paper presents an additive-based approach to the formulation of thermoelectric materials suitable for screen printing. Such printing processes are a likely route to such thermoelectric applications as micro-generators for wireless sensor networks and medical devices, but require the development of materials that can be sintered at ambient pressure and low temperatures. Using a rapid screening process, we identify the eutectic combination of antimony and tellurium as an additive for bismuth-antimony-telluride that enables good thermoelectric performance without a high pressure step. An optimized composite of 15 weight percent Sb7.5Te92.5 in Bi0.5Sb1.5Te3 is scaled up and formulated into a screen-printable paste. Samples fabricated from this paste achieve a thermoelectric figure of merit (ZT) of 0.74 using a maximum processing temperature of 748 K and a total thermal processing budget of 12 K-hours.

Current transport mechanisms in mercury cadmium telluride diode

Energy Technology Data Exchange (ETDEWEB)

Gopal, Vishnu, E-mail: vishnu-46@yahoo.com, E-mail: wdhu@mail.sitp.ac.cn [Institute of Defence Scientists and Technologists, CFEES Complex, Brig. S. K. Majumdar Marg, Delhi 110054 (India); Li, Qing; He, Jiale; Hu, Weida, E-mail: vishnu-46@yahoo.com, E-mail: wdhu@mail.sitp.ac.cn [National Lab for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China); He, Kai; Lin, Chun [Key Laboratory of Infrared Imaging Materials and Detectors, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China)

2016-08-28

This paper reports the results of modelling of the current-voltage characteristics (I-V) of a planar mid-wave Mercury Cadmium Telluride photodiode in a gate controlled diode experiment. It is reported that the diode exhibits nearly ideal I-V characteristics under the optimum surface potential leading to the minimal surface leakage current. Deviations from the optimum surface potential lead to non ideal I–V characteristics, indicating a strong relationship between the ideality factor of the diode with its surface leakage current. Diode's I–V characteristics have been modelled over a range of gate voltages from −9 V to −2 V. This range of gate voltages includes accumulation, flat band, and depletion and inversion conditions below the gate structure of the diode. It is shown that the I–V characteristics of the diode can be very well described by (i) thermal diffusion current, (ii) ohmic shunt current, (iii) photo-current due to background illumination, and (iv) excess current that grows by the process of avalanche multiplication in the gate voltage range from −3 V to −5 V that corresponds to the optimum surface potential. Outside the optimum gate voltage range, the origin of the excess current of the diode is associated with its high surface leakage currents. It is reported that the ohmic shunt current model applies to small surface leakage currents. The higher surface leakage currents exhibit a nonlinear shunt behaviour. It is also shown that the observed zero-bias dynamic resistance of the diode over the entire gate voltage range is the sum of ohmic shunt resistance and estimated zero-bias dynamic resistance of the diode from its thermal saturation current.

Formation and acceleration of uniformly filled ellipsoidal electron bunches obtained via space-charge-driven expansion from a cesium-telluride photocathode

Directory of Open Access Journals (Sweden)

P. Piot

2013-01-01

Full Text Available We report the experimental generation, acceleration, and characterization of a uniformly filled electron bunch obtained via space-charge-driven expansion (often referred to as “blow-out regime” in an L-band (1.3-GHz radiofrequency photoinjector. The beam is photoemitted from a cesium-telluride semiconductor photocathode using a short (<200  fs ultraviolet laser pulse. The produced electron bunches are characterized with conventional diagnostics and the signatures of their ellipsoidal character are observed. We especially demonstrate the production of ellipsoidal bunches with charges up to ∼0.5  nC corresponding to a ∼20-fold increase compared to previous experiments with metallic photocathodes.

Californium interrogation prompt neutron (CIPN) instrument for non-destructive assay of spent nuclear fuel—Design concept and experimental demonstration

International Nuclear Information System (INIS)

Henzlova, D.; Menlove, H.O.; Rael, C.D.; Trellue, H.R.; Tobin, S.J.; Park, Se-Hwan; Oh, Jong-Myeong; Lee, Seung-Kyu; Ahn, Seong-Kyu; Kwon, In-Chan; Kim, Ho-Dong

2016-01-01

This paper presents results of the first experimental demonstration of the Californium Interrogation Prompt Neutron (CIPN) instrument developed within a multi-year effort launched by the Next Generation Safeguards Initiative Spent Fuel Project of the United States Department of Energy. The goals of this project focused on developing viable non-destructive assay techniques with capabilities to improve an independent verification of spent fuel assembly characteristics. For this purpose, the CIPN instrument combines active and passive neutron interrogation, along with passive gamma-ray measurements, to provide three independent observables. This paper describes the initial feasibility demonstration of the CIPN instrument, which involved measurements of four pressurized-water-reactor spent fuel assemblies with different levels of burnup and two initial enrichments. The measurements were performed at the Post-Irradiation Examination Facility at the Korea Atomic Energy Institute in the Republic of Korea. The key aim of the demonstration was to evaluate CIPN instrument performance under realistic deployment conditions, with the focus on a detailed assessment of systematic uncertainties that are best evaluated experimentally. The measurements revealed good positioning reproducibility, as well as a high degree of insensitivity of the CIPN instrument's response to irregularities in a radial burnup profile. Systematic uncertainty of individual CIPN instrument signals due to assembly rotation was found to be <4.5%, even for assemblies with fairly extreme gradients in the radial burnup profile. These features suggest that the CIPN instrument is capable of providing a good representation of assembly average characteristics, independent of assembly orientation in the instrument.

Californium interrogation prompt neutron (CIPN) instrument for non-destructive assay of spent nuclear fuel—Design concept and experimental demonstration

Energy Technology Data Exchange (ETDEWEB)

Henzlova, D., E-mail: henzlova@lanl.gov [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Menlove, H.O.; Rael, C.D.; Trellue, H.R.; Tobin, S.J. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Park, Se-Hwan; Oh, Jong-Myeong; Lee, Seung-Kyu; Ahn, Seong-Kyu; Kwon, In-Chan; Kim, Ho-Dong [Korea Atomic Energy Research Institute, Daejeong (Korea, Republic of)

2016-01-11

This paper presents results of the first experimental demonstration of the Californium Interrogation Prompt Neutron (CIPN) instrument developed within a multi-year effort launched by the Next Generation Safeguards Initiative Spent Fuel Project of the United States Department of Energy. The goals of this project focused on developing viable non-destructive assay techniques with capabilities to improve an independent verification of spent fuel assembly characteristics. For this purpose, the CIPN instrument combines active and passive neutron interrogation, along with passive gamma-ray measurements, to provide three independent observables. This paper describes the initial feasibility demonstration of the CIPN instrument, which involved measurements of four pressurized-water-reactor spent fuel assemblies with different levels of burnup and two initial enrichments. The measurements were performed at the Post-Irradiation Examination Facility at the Korea Atomic Energy Institute in the Republic of Korea. The key aim of the demonstration was to evaluate CIPN instrument performance under realistic deployment conditions, with the focus on a detailed assessment of systematic uncertainties that are best evaluated experimentally. The measurements revealed good positioning reproducibility, as well as a high degree of insensitivity of the CIPN instrument's response to irregularities in a radial burnup profile. Systematic uncertainty of individual CIPN instrument signals due to assembly rotation was found to be <4.5%, even for assemblies with fairly extreme gradients in the radial burnup profile. These features suggest that the CIPN instrument is capable of providing a good representation of assembly average characteristics, independent of assembly orientation in the instrument.

Influence of germanium nano-inclusions on the thermoelectric power factor of bulk bismuth telluride alloy

International Nuclear Information System (INIS)

Satyala, Nikhil; Zamanipour, Zahra; Norouzzadeh, Payam; Krasinski, Jerzy S.; Vashaee, Daryoosh; Tahmasbi Rad, Armin; Tayebi, Lobat

2014-01-01

Nanocomposite thermoelectric compound of bismuth telluride (Bi 2 Te 3 ) with 5 at. % germanium nano-inclusions was prepared via mechanically alloying and sintering techniques. The influence of Ge nano-inclusions and long duration annealing on the thermoelectric properties of nanostructured Bi 2 Te 3 were investigated. It was found that annealing has significant effect on the carrier concentration, Seebeck coefficient, and the power factor of the thermoelectric compound. The systematic heat treatment also reduced the density of donor type defects thereby decreasing the electron concentration. While the as-pressed nanocomposite materials showed n-type properties, it was observed that with the increase of annealing time, the nanocomposite gradually transformed to an abundantly hole-dominated (p-type) sample. The long duration annealing (∼500 h) resulted in a significantly enhanced electrical conductivity pertaining to the augmentation in the density and the structural properties of the sample. Therefore, a simultaneous enhancement in both electrical and Seebeck coefficient characteristics resulted in a remarkable increase in the thermoelectric power factor.

Angular dependence of magnetization reversal in epitaxial chromium telluride thin films with perpendicular magnetic anisotropy

Energy Technology Data Exchange (ETDEWEB)

Pramanik, Tanmoy, E-mail: pramanik.tanmoy@utexas.edu; Roy, Anupam, E-mail: anupam@austin.utexas.edu; Dey, Rik, E-mail: rikdey@utexas.edu; Rai, Amritesh; Guchhait, Samaresh; Movva, Hema C.P.; Hsieh, Cheng-Chih; Banerjee, Sanjay K.

2017-09-01

Highlights: • Perpendicular magnetic anisotropy in epitaxial Cr{sub 2}Te{sub 3} has been investigated. • Presence of a relatively strong second order anisotropy contribution is observed. • Magnetization reversal is explained quantitatively using a 1D defect model. • Relative roles of nucleation and pinning in magnetization reversal are discussed. • Domain structures and switching process are visualized by micromagnetic simulation. - Abstract: We investigate magnetic anisotropy and magnetization reversal mechanism in chromium telluride thin films grown by molecular beam epitaxy. We report existence of strong perpendicular magnetic anisotropy in these thin films, along with a relatively strong second order anisotropy contribution. The angular variation of the switching field observed from the magnetoresistance measurement is explained quantitatively using a one-dimensional defect model. The model reveals the relative roles of nucleation and pinning in the magnetization reversal, depending on the applied field orientation. Micromagnetic simulations are performed to visualize the domain structure and switching process.

Effect of the interface on the mechanical properties and thermal conductivity of bismuth telluride films

Science.gov (United States)

Lai, Tang-Yu; Wang, Kuan-Yu; Fang, Te-Hua; Huang, Chao-Chun

2018-02-01

Bismuth telluride (Bi2Te3) is a type of thermoelectric material used for energy generation that does not cause pollution. Increasing the thermoelectric conversion efficiency (ZT) is one of the most important steps in the development of thermoelectric components. In this study, we use molecular dynamics to investigate the mechanical properties and thermal conductivity of quintuple layers of Bi2Te3 nanofilms with different atomic arrangements at the interface and study the effects of varying layers, angles, and grain boundaries. The results indicate that the Bi2Te3 nanofilm perfect substrate has the ideal Young’s modulus and thermal conductivity, and the maximum yield stress is observed for a thickness of ∼90 Å. As the interface changed, the structural disorder of atomic arrangement affected the mechanical properties; moreover, the phonons encounter lattice disordered atomic region will produce scattering reduce heat conduction. The results of this investigation are helpful for the application of Bi2Te3 nanofilms as thermoelectric materials.

Molecular precursors for the phase-change material germanium-antimony-telluride, Ge{sub 2}Sb{sub 2}Te{sub 5} (GST)

Energy Technology Data Exchange (ETDEWEB)

Harmgarth, Nicole; Zoerner, Florian; Engelhardt, Felix; Edelmann, Frank T. [Chemisches Institut, Otto-von-Guericke-Universitaet Magdeburg (Germany); Liebing, Phil [Laboratorium fuer Anorganische Chemie, ETH Zuerich (Switzerland); Burte, Edmund P.; Silinskas, Mindaugas [Institut fuer Mikro- und Sensorsysteme, Otto-von-Guericke-Universitaet Magdeburg (Germany)

2017-10-04

This review provides an overview of the precursor chemistry that has been developed around the phase-change material germanium-antimony-telluride, Ge{sub 2}Sb{sub 2}Te{sub 5} (GST). Thin films of GST can be deposited by employing either chemical vapor deposition (CVD) or atomic layer deposition (ALD) techniques. In both cases, the success of the layer deposition crucially depends on the proper choice of suitable molecular precursors. Previously reported processes mainly relied on simple alkoxides, alkyls, amides and halides of germanium, antimony, and tellurium. More sophisticated precursor design provided a number of promising new aziridinides and guanidinates. (copyright 2017 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Templated growth of cadmium zinc telluride (CZT) nanowires using pulsed-potentials in hot non-aqueous solution

International Nuclear Information System (INIS)

Gandhi, T.; Raja, K.S.; Misra, M.

2006-01-01

A single step non-aqueous electrodeposition of cadmium zinc telluride (CZT) nanowires on nanoporous TiO 2 substrate was investigated under pulsed-potential conditions. Propylene carbonate was used as the non-aqueous medium. Cyclic voltammogram studies were carried out to understand the growth mechanism of CZT. EDAX and XRD measurements indicated formation of a compound semiconductor with a stoichiometry of Cd 1-x Zn x Te, where x varied between 0.04 and 0.2. Variation of the pulsed-cathodic potentials could modulate the composition of the CZT. More negative cathodic potentials resulted in increased Zn content. The nanowires showed an electronic band gap of about 1.6 eV. Mott-Schottky analyses indicated p-type semiconductor properties of both as-deposited and annealed CZT materials. Increase in Zn content increased the charge carrier density. Annealing of the deposits resulted in lower charge carrier densities, in the order of 10 15 cm -3

Effect of preparation procedure and nanostructuring on the thermoelectric properties of the lead telluride-based material system AgPb{sub m}BiTe{sub 2+m} (BLST-m)

Energy Technology Data Exchange (ETDEWEB)

Falkenbach, Oliver; Koch, Guenter; Schlecht, Sabine [Institute for Inorganic and Analytical Chemistry, Justus-Liebig-University, Heinrich-Buff-Ring 17, D-35392 Giessen (Germany); Schmitz, Andreas [Institute of Materials Research, German Aerospace Center (DLR), D-51170 Cologne (Germany); Hartung, David; Klar, Peter J. [Institute of Experimental Physics I, Justus-Liebig-University, Heinrich-Buff-Ring 16, D-35392 Giessen (Germany); Dankwort, Torben; Kienle, Lorenz [Institute for Material Science, Christian-Albrechts-University, Kaiserstrasse 2, D-24143 Kiel (Germany); Mueller, Eckhard, E-mail: Eckhard.Mueller@dlr.de [Institute for Inorganic and Analytical Chemistry, Justus-Liebig-University, Heinrich-Buff-Ring 17, D-35392 Giessen (Germany); Institute of Materials Research, German Aerospace Center (DLR), D-51170 Cologne (Germany)

2016-06-07

We report on the preparation and thermoelectric properties of the quaternary system AgPb{sub m}BiTe{sub 2+m} (Bismuth-Lead-Silver-Tellurium, BLST-m) that were nanostructured by mechanical alloying. Nanopowders of various compositions were compacted by three different methods: cold pressing/annealing, hot pressing, and short term sintering. The products are compared with respect to microstructure and sample density. The thermoelectric properties were measured: thermal conductivity in the temperature range from 300 K to 800 K and electrical conductivity and Seebeck coefficient between 100 K and 800 K. The compacting method and the composition had a substantial impact on carrier concentration and mobility as well as on the thermoelectric parameters. Room temperature Hall measurements yielded carrier concentrations in the order of 10{sup 19 }cm{sup −3}, slightly increasing with increasing content of the additive silver bismuth telluride to the lead telluride base. ZT values close to the ones of bulk samples were achieved. X-ray diffraction and transmission electron microscopy (TEM) showed macroscopically homogeneous distributions of the constituting elements inside the nanopowders ensembles, indicating a solid solution. However, high resolution transmission electron microscopy (HRTEM) revealed disorder on the nanoscale inside individual nanopowders grains.

A simple fast microwave-assisted synthesis of thermoelectric bismuth telluride nanoparticles from homogeneous reaction-mixture

Energy Technology Data Exchange (ETDEWEB)

Pradhan, Susmita [Jadavpur University, Department of Instrumentation Science (India); Das, Rashmita [Jadavpur University, Department of Instrumentation and Electronics Engineering (India); Bhar, Radhaballabh [Jadavpur University, Department of Instrumentation Science (India); Bandyopadhyay, Rajib [Jadavpur University, Department of Instrumentation and Electronics Engineering (India); Pramanik, Panchanan, E-mail: pramanik1946@gmail.com [GLA University, Department of Chemistry and Nanoscience (India)

2017-02-15

A new simple chemical method for synthesis of nanocrystalline bismuth telluride (Bi{sub 2}Te{sub 3}) has been developed by microwave assisted reduction of homogeneous tartrate complexes of bismuth and tellurium metal ions with hydrazine. The reaction is performed at pH 10. The nano-crystallites have rhombohedral phase identified by XRD. The size distribution of nanoparticle is narrow and it ranges between 50 to 70 nm. FESEM shows that the fine powders are composed of small crystallites. The TEM micrographs show mostly deformed spherical particles and the lattice fringes are found to be 0.137 nm. Energy dispersive X-ray spectroscopy (EDX) analysis shows the atomic composition ratio between bismuth and tellurium is 2:3. Thermoelectric properties of the materials are studied after sintering by spark plasma sintering method (SPS). The grain size of the material after sintering is in the nanometer range. The material shows enhanced Seebeck coefficient and electrical conductivity value at 300 K. The figure of merit is found to be 1.18 at 300 K.

Effect of reducing agent strength on the growth and thermoelectric performance of nanocrystalline bismuth telluride

Science.gov (United States)

Nour, Asmaa; Hassan, Nazly; Refaat, Heba M.; Soliman, Hesham M. A.; El-Dissouky, A.

2018-03-01

A novel combination of Trizma, as an environmentally friendly chelating agent, with either weak or strong reducing agent was used to produce n-type bismuth telluride (Bi2Te3) nanocrystals via water-based chemical route. The synthesized powders were consolidated into pellets utilizing spark plasma sintering (SPS). The sintered n-type pellets exhibited potentially high electrical conductivities (5.29 × 105 and 5.23 × 105 S.m‑1) and low lattice thermal conductivities (0.12 and 0.25 Wm‑1K‑1) respectively. These thermoelectric (TE) properties suggested that the partially coherent boundaries permitted significant phonons scattering and electrons transfer. These led to an enhanced figure-of-merit (ZT) values (0.52 and 0.97), which are considered to be significant among the reported ZT values at room-temperature for the undoped synthesized n-type Bi2Te3 nanoparticles. Therefore, the current investigation displayed an efficient method to improve ZT of TE materials via nanostructure orchestrating, resulting in a worthy candidate n-type nanostructured Bi2Te3 for room-temperature TE applications.

Fluorescence Stability of Mercaptopropionic Acid Capped Cadmium Telluride Quantum Dots in Various Biochemical Buffers.

Science.gov (United States)

Borse, Vivek; Kashikar, Adisha; Srivastava, Rohit

2018-04-01

Quantum dots are the semiconductor nanocrystals having unique optical and electronic properties. Quantum dots are category of fluorescent labels utilized for biological tagging, biosensing, bioassays, bioimaging and in vivo imaging as they exhibit very small size, signal brightness, photostability, tuning of light emission range, longer photoluminescence decay time as compared to organic dyes. In this work, we have synthesized and characterized mercaptopropionic acid capped cadmium telluride quantum dots (MPA-CdTe QDs) using hydrothermal method. The study further reports fluorescence intensity stability of quantum dots suspended in different buffers of varying concentration (1-100 mM), stored at various photophysical conditions. Fluorescence intensity values were reduced with increase in buffer concentration. When the samples were stored at room temperature in ambient light condition the quantum dots suspended in different buffers lost the fluorescence intensity after day 15 (except TRIS II). Fluorescence intensity values were found stable for more than 30 days when the samples were stored in dark condition. Samples stored in refrigerator displayed modest fluorescence intensity even after 300 days of storage. Thus, storage of MPA-CdTe QDs in refrigerator may be the suitable choice to maintain its fluorescence stability for longer time for further application.

Cadmium telluride nanoparticles loaded on activated carbon as adsorbent for removal of sunset yellow

Science.gov (United States)

Ghaedi, M.; Hekmati Jah, A.; Khodadoust, S.; Sahraei, R.; Daneshfar, A.; Mihandoost, A.; Purkait, M. K.

2012-05-01

Adsorption is a promising technique for decolorization of effluents of textile dyeing industries but its application is limited due to requirement of high amounts of adsorbent required. The objective of this study was to assess the potential of cadmium telluride nanoparticles loaded onto activated carbon (CdTN-AC) for the removal of sunset yellow (SY) dye from aqueous solution. Adsorption studies were conducted in a batch mode varying solution pH, contact time, initial dye concentration, CdTN-AC dose, and temperature. In order to investigate the efficiency of SY adsorption on CdTN-AC, pseudo-first-order, pseudo-second-order, Elovich, and intra-particle diffusion kinetic models were studied. It was observed that the pseudo-second-order kinetic model fits better than other kinetic models with good correlation coefficient. Equilibrium data were fitted to the Langmuir model. Thermodynamic parameters such as enthalpy, entropy, activation energy, and sticking probability were also calculated. It was found that the sorption of SY onto CdTN-AC was spontaneous and endothermic in nature. The proposed adsorbent is applicable for SY removal from waste of real effluents including pea-shooter, orange drink and jelly banana with efficiency more than 97%.

Low-cost cadmium zinc telluride radiation detectors based on electron-transport-only designs

International Nuclear Information System (INIS)

Brunett, B.A.; Lund, J.C.; Van Scyoc, J.M.; Hilton, N.R.; Lee, E.Y.; James, R.B.

1999-01-01

The goal of this project was to utilize a novel device design to build a compact, high resolution, room temperature operated semiconductor gamma ray sensor. This sensor was constructed from a cadmium zinc telluride (CZT) crystal. It was able to both detect total radiation intensity and perform spectroscopy on the detected radiation. CZT detectors produced today have excellent electron charge carrier collection, but suffer from poor hole collection. For conventional gamma-ray spectrometers, both the electrons and holes must be collected with high efficiency to preserve energy resolution. The requirement to collect the hole carriers, which have relatively low lifetimes, limits the efficiency and performance of existing experimental devices. By implementing novel device designs such that the devices rely only on the electron signal for energy information, the sensitivity of the sensors for detecting radiation can be increased substantially. In this report the authors describe a project to develop a new type of electron-only CZT detector. They report on their successful efforts to design, implement and test these new radiation detectors. In addition to the design and construction of the sensors the authors also report, in considerable detail, on the electrical characteristics of the CZT crystals used to make their detectors

Thermochemical properties of silver tellurides including empressite (AgTe) and phase diagrams for Ag-Te and Ag-Te-O

Science.gov (United States)

Voronin, Mikhail V.; Osadchii, Evgeniy G.; Brichkina, Ekaterina A.

2017-10-01

This study compiles original experimental and literature data on the thermodynamic properties (ΔfG°, S°, ΔfH°) of silver tellurides (α-Ag2Te, β-Ag2Te, Ag1.9Te, Ag5Te3, AgTe) obtained by the method of solid-state galvanic cell with the RbAg4I5 and AgI solid electrolytes. The thermodynamic data for empressite (AgTe, pure fraction from Empress Josephine Mine, Colorado USA) have been obtained for the first time by the electrochemical experiment with the virtual reaction Ag + Te = AgTe. The Ag-Te phase diagrams in the T - x and log fTe2 (gas) - 1/ T coordinates have been refined, and the ternary Ag-Te-O diagrams with Ag-Te-TeO2 (paratellurite) composition range have been calculated.

Rapid long-wave infrared laser-induced breakdown spectroscopy measurements using a mercury-cadmium-telluride linear array detection system.

Science.gov (United States)

Yang, Clayton S-C; Brown, Eiei; Kumi-Barimah, Eric; Hommerich, Uwe; Jin, Feng; Jia, Yingqing; Trivedi, Sudhir; D'souza, Arvind I; Decuir, Eric A; Wijewarnasuriya, Priyalal S; Samuels, Alan C

2015-11-20

In this work, we develop a mercury-cadmium-telluride linear array detection system that is capable of rapidly capturing (∼1-5  s) a broad spectrum of atomic and molecular laser-induced breakdown spectroscopy (LIBS) emissions in the long-wave infrared (LWIR) region (∼5.6-10  μm). Similar to the conventional UV-Vis LIBS, a broadband emission spectrum of condensed phase samples covering the whole 5.6-10 μm region can be acquired from just a single laser-induced microplasma or averaging a few single laser-induced microplasmas. Atomic and molecular signature emission spectra of solid inorganic and organic tablets and thin liquid films deposited on a rough asphalt surface are observed. This setup is capable of rapidly probing samples "as is" without the need of elaborate sample preparation and also offers the possibility of a simultaneous UV-Vis and LWIR LIBS measurement.

Synthesis, characterization and enhanced thermoelectric performance of structurally ordered cable-like novel polyaniline–bismuth telluride nanocomposite

International Nuclear Information System (INIS)

Chatterjee, Krishanu; Mitra, Mousumi; Banerjee, Dipali; Kargupta, Kajari; Ganguly, Saibal

2013-01-01

Bismuth telluride (Bi 2 Te 3 ) nanorods and polyaniline (PANI) nanoparticles have been synthesized by employing solvothermal and chemical oxidative processes, respectively. Nanocomposites, comprising structurally ordered PANI preferentially grown along the surface of a Bi 2 Te 3 nanorods template, are synthesized using in situ polymerization. X-ray powder diffraction, UV–vis and Raman spectral analysis confirm the highly ordered chain structure of PANI on Bi 2 Te 3 nanorods, leading to a higher extent of doping, higher chain mobility and enhancement of the thermoelectric performance. Above 380 K, the PANI–Bi 2 Te 3 nanocomposite with a core–shell/cable-like structure exhibits a higher thermoelectric power factor than either pure PANI or Bi 2 Te 3 . At room temperature the thermal conductivity of the composite is lower than that of its pure constituents, due to selective phonon scattering by the nanointerfaces designed in the PANI–Bi 2 Te 3 nanocable structures. The figure of merit of the nanocomposite at room temperature is comparable to the values reported in the literature for bulk polymer-based composite thermoelectric materials. (paper)

Bismuth telluride topological insulator nanosheet saturable absorbers for q-switched mode-locked Tm:ZBLAN waveguide lasers

Energy Technology Data Exchange (ETDEWEB)

Jiang, Xiantao; Gross, Simon; Withford, Michael J.; Fuerbach, Alexander [Centre for Ultrahigh bandwidth Devices for Optical Systems (CUDOS) and MQ Photonics Research Centre, Dept. of Physics and Astronomy, Macquarie Univ., NSW (Australia); Zhang, Han; Guo, Zhinan [SZU-NUS Collaborative Innovation Centre for Optoelectronic Science and Technology, Key Lab. of Optoelectronic Devices and Systems of Ministry of Education, College of Optoelectronic Engineering, Shenzhen Univ. (China)

2016-08-15

Nanosheets of bismuth telluride (Bi{sub 2}Te{sub 3}), a topological insulator material that exhibits broadband saturable absorption due to its non-trivial Dirac-cone like energy structure, are utilized to generate short pulses from Tm:ZBLAN waveguide lasers. By depositing multiple layers of a carefully prepared Bi{sub 2}Te{sub 3} solution onto a glass substrate, the modulation depth and the saturation intensity of the fabricated devices can be controlled and optimized. This approach enables the realization of saturable absorbers that feature a modulation depth of 13% and a saturation intensity of 997 kW/cm{sup 2}. For the first time to our knowledge, Q-switched mode-locked operation of a linearly polarized mid-IR ZBLAN waveguide chip laser was realized in an extended cavity configuration using the topological insulator Bi{sub 2}Te{sub 3}. The maximum average output power of the laser is 16.3 mW and the Q-switched and mode-locked repetition rates are 44 kHz and 436 MHz, respectively. (copyright 2016 by WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

Processing and Characterization of Thin Cadmium Telluride Solar Cells

Science.gov (United States)

Wojtowicz, Anna

Cadmium telluride (CdTe) has the highest theoretical limit to conversion efficiency of single-junction photovoltaic (PV) technologies today. However, despite a maximum theoretical open-circuit voltage of 1.20 V, record devices have historically had voltages pinned around only 900 mV. Voltage losses due to high recombination rates remains to be the most complex hurdle to CdTe technology today, and the subject of on-going research in the physics PV group at Colorado State University. In this work, an ultrathin CdTe device architecture is proposed in an effort to reduce bulk recombination and boost voltages. By thinning the CdTe layer, a device's internal electric field extends fully towards the back contact. This quickly separates electrons-hole pairs throughout the bulk of the device and reduces overall recombination. Despite this advantage, very thin CdTe layers also present a unique set of optical and electrical challenges which result in performance losses not as prevalent in thicker devices. When fabricating CdTe solar cells, post-deposition treatments applied to the absorber layer are a critical step for achieving high efficiency devices. Exposure of the polycrystalline CdTe film to a chlorine species encourages the passivation of dangling bonds and larger grain formation, while copper-doping improves device uniformity and voltages. This work focuses on experiments conducted via close-space sublimation to optimize CdCl2 and CuCl treatments for thin CdTe solar cells. Sweeps of both exposure and anneal time were performed for both post-deposition treatments on CdTe devices with 1.0 mum absorber layers. The results demonstrate that thin CdTe devices require substantially less post-deposition processing than standard thicker devices as expected. Additionally, the effects of CdTe growth temperature on thin devices is briefly investigated. The results suggest that higher growth temperatures lead to both electrical and stoichiometric changes in CdTe closely associated

Study of a high-resolution, 3-D positioning cadmium zinc telluride detector for PET

Science.gov (United States)

Gu, Y; Matteson, J L; Skelton, R T; Deal, A C; Stephan, E A; Duttweiler, F; Gasaway, T M; Levin, C S

2011-01-01

This paper investigates the performance of 1 mm resolution Cadmium Zinc Telluride (CZT) detectors for positron emission tomography (PET) capable of positioning the 3-D coordinates of individual 511 keV photon interactions. The detectors comprise 40 mm × 40 mm × 5 mm monolithic CZT crystals that employ a novel cross-strip readout with interspersed steering electrodes to obtain high spatial and energy resolution. The study found a single anode FWHM energy resolution of 3.06±0.39% at 511 keV throughout most the detector volume. Improved resolution is expected with properly shielded front-end electronics. Measurements made using a collimated beam established the efficacy of the steering electrodes in facilitating enhanced charge collection across anodes, as well as a spatial resolution of 0.44±0.07 mm in the direction orthogonal to the electrode planes. Finally, measurements based on coincidence electronic collimation yielded a point spread function with 0.78±0.10 mm FWHM, demonstrating 1 mm spatial resolution capability transverse to the anodes – as expected from the 1 mm anode pitch. These findings indicate that the CZT-based detector concept has excellent performance and shows great promise for a high-resolution PET system. PMID:21335649

Study of a high-resolution, 3D positioning cadmium zinc telluride detector for PET.

Science.gov (United States)

Gu, Y; Matteson, J L; Skelton, R T; Deal, A C; Stephan, E A; Duttweiler, F; Gasaway, T M; Levin, C S

2011-03-21

This paper investigates the performance of 1 mm resolution cadmium zinc telluride (CZT) detectors for positron emission tomography (PET) capable of positioning the 3D coordinates of individual 511 keV photon interactions. The detectors comprise 40 mm × 40 mm × 5 mm monolithic CZT crystals that employ a novel cross-strip readout with interspersed steering electrodes to obtain high spatial and energy resolution. The study found a single anode FWHM energy resolution of 3.06 ± 0.39% at 511 keV throughout most of the detector volume. Improved resolution is expected with properly shielded front-end electronics. Measurements made using a collimated beam established the efficacy of the steering electrodes in facilitating enhanced charge collection across anodes, as well as a spatial resolution of 0.44 ± 0.07 mm in the direction orthogonal to the electrode planes. Finally, measurements based on coincidence electronic collimation yielded a point spread function with 0.78 ± 0.10 mm FWHM, demonstrating 1 mm spatial resolution capability transverse to the anodes-as expected from the 1 mm anode pitch. These findings indicate that the CZT-based detector concept has excellent performance and shows great promise for a high-resolution PET system.

Freeze drying method for preparing radiation source material

International Nuclear Information System (INIS)

Mosley, W.C.; Smith, P.K.

1976-01-01

Fabrication of a neutron source is specifically claimed. A palladium/californium solution is freeze dried to form a powder which, through conventional powder metallurgy, is shaped into a source containing the californium evenly distributed through a palladium metal matrix. (E.C.B.)

Spark plasma sintered bismuth telluride-based thermoelectric materials incorporating dispersed boron carbide

Energy Technology Data Exchange (ETDEWEB)

Williams, H.R., E-mail: hugo.williams@leicester.ac.uk [Department of Engineering, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Ambrosi, R.M. [Space Research Centre, Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Chen, K. [School of Engineering and Materials Science, Queen Mary, University of London, Mile End Road, London E1 4NS (United Kingdom); Friedman, U. [Department of Engineering, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Ning, H.; Reece, M.J. [School of Engineering and Materials Science, Queen Mary, University of London, Mile End Road, London E1 4NS (United Kingdom); Robbins, M.C.; Simpson, K. [European Thermodynamics Ltd., 8 Priory Business Park, Wistow Road, Kibworth LE8 0R (United Kingdom); Stephenson, K. [European Space Agency, ESTEC TEC-EP, Keplerlaan 1, 2201AZ Noordwijk (Netherlands)

2015-03-25

Highlights: • Nano-B{sub 4}C reinforced Bi{sub 0.5}Sb{sub 1.5}Te{sub 3} p-type thermoelectric produced by SPS. • Addition of B{sub 4}C up to 0.2 vol% to SPS’d material has little effect on zT. • Vickers hardness improved by 27% by adding 0.2 vol% B{sub 4}C. • Fracture toughness of SPS material: K{sub IC} = 0.80 MPa m{sup 1/2} by SEVNB. • Mechanical properties much better than commercial directionally solidified material. - Abstract: The mechanical properties of bismuth telluride based thermoelectric materials have received much less attention in the literature than their thermoelectric properties. Polycrystalline p-type Bi{sub 0.5}Sb{sub 1.5}Te{sub 3} materials were produced from powder using spark plasma sintering (SPS). The effects of nano-B{sub 4}C addition on the thermoelectric performance, Vickers hardness and fracture toughness were measured. Addition of 0.2 vol% B{sub 4}C was found to have little effect on zT but increased hardness by approximately 27% when compared to polycrystalline material without B{sub 4}C. The K{sub IC} fracture toughness of these compositions was measured as 0.80 MPa m{sup 1/2} by Single-Edge V-Notched Beam (SEVNB). The machinability of polycrystalline materials produced by SPS was significantly better than commercially available directionally solidified materials because the latter is limited by cleavage along the crystallographic plane parallel to the direction of solidification.

N-hydroxysuccinimide-mediated photoelectrooxidation of aliphatic alcohols based on cadmium telluride nanoparticles decorated graphene nanosheets

International Nuclear Information System (INIS)

Navaee, Aso; Salimi, Abdollah

2013-01-01

A simple nonenzymatic electrochemical protocol is proposed for the oxidation of aliphatic alcohols using formed N-hydroxysuccinimide (NHS) radical cation on the graphene nanosheets/L-cysteine/cadmium telluride quantum dot (QD) nanocomposite (GNs/Cys/CdTe) modified glassy carbon (GC) electrode. At first, graphene oxide (GO) is chemically synthesized from graphite after which Cys is covalently functionalized to GO through formation of amide bonds between carboxylic acid groups of GO and amine groups of Cys. The resulting GNs/Cys is used as a capping agent to synthesize CdTe QD nanoparticles. After the characterization of the as-made nanocomposite which confirmed the successful attachment of CdTe nanoparticles to the GNs, the ability of the GNs/Cys/CdTe modified GC electrode toward the nonenzymatic ethanol electrooxidation is examined in the presence of NHS as an effective mediating system. Our results revealed that the proposed system possess a good activity to NHS electrooxidation and subsequently, ethanol oxidation. Moreover, the GNs/Cys/CdTe modified electrode displayed a significant photoelectrocatalytic activity toward the ethanol oxidation upon illumination by visible light. The photoactive GNs/Cys/CdTe nanohybrid presented here showing favorable photoelectrochemical features for nonenzymatic aliphatic alcohols oxidation may hold great promise to the development of electrochemical sensors and biofuel cells

Investigation of the Electronic Properties of Cadmium Zinc Telluride (CZT) Detectors using a Nuclear Microprobe

International Nuclear Information System (INIS)

BRUNETT, BRUCE A.; DOYLE, BARNEY L.; JAMES, RALPH B.; VIZKELETHY, GYORGY; WALSH, DAVID S.

1999-01-01

The electronic transport properties of Cadmium Zinc Telluride (CZT) determine the charge collection efficiency (i.e. the signal quality) of CZT detectors. These properties vary on both macroscopic and microscopic scale and depend on the presence of impurities and defects introduced during the crystal growth. Ion Beam Induced Charge Collection (IBICC) is a proven method to measure the charge collection efficiency. Using an ion microbeam, the charge collection efficiency can be mapped with submicron resolution, and the map of electronic properties (such as drift length) can be calculated from the measurement. A more sophisticated version of IBICC, the Time Resolved IBICC (TRIBICC) allows them to determine the mobility and the life time of the charge carriers by recording and analyzing the transient waveform of the detector signal. Furthermore, lateral IBICC and TRIBICC can provide information how the charge collection efficiency depends on the depth where the charge carriers are generated. This allows one to deduce information on the distribution of the electric field and transport properties of the charge carriers along the detector axis. IBICC and TRIBICC were used at the Sandia microbeam facility to image electronic properties of several CZT detectors. From the lateral TRIBICC measurement the electron and hole drift length profiles were calculated

The crystal structures and powder diffraction patterns of the uranium tellurides

Energy Technology Data Exchange (ETDEWEB)

Snyder, R.L. (State Univ. of New York, Alfred, NY (USA). Inst. of Ceramic Superconductivity); Nichols, M.C.; Boehme, D.R. (Sandia National Labs., Livermore, CA (USA))

1990-10-03

A critical review of all of the reported structures and powder diffraction patterns in the uranium telluride system has been undertaken. Structures that are correct: Cubic -- UTe: no experimental pattern exists. Retain calculated 15--865. Cubic --U{sub 3}Te{sub 4}: retain the poor quality 12--610 but adopt the pattern calculated here. Cubic U{sub 2}Te{sub 3}: no experimental pattern exists. Adopt pattern calculated here. Orthorhombic UTe{sub 2}: Adopt the new pattern of Boehme et al. Monoclinic {alpha}UTe{sub 3} Adopt the new pattern of Boehme et al. Monoclinic {alpha}UTe{sub 3} Adopt the new pattern of Boehme et al. Orthorhombic {beta}UTe{sub 3}: Adopt pattern calculated here. Orthorhombic UTe{sub 5}: Adopt the new pattern of Boehme et al. Structures in need of refinement: Orthorhombic U{sub 2}Te{sub 3}:Adopt pattern calculated here over 34--807. Hexagonal U{sub 7}Te{sub 12}: Adopt pattern calculated here but retain 24--1368. Orthorhombic UTe{sub 1.78}: Adopt pattern calculated here and retain our modified 21--1404 reported for U{sub 4}Te{sub 7}. Orthorhombic UTe{sub 2.5}: Adopt pattern calculated here. Orthorhombic UTe{sub 3.4}: Accept recent pattern of Boehme et al. Phases for which no structures or reliable patterns exist: Orthorhombic U{sub 3}Te{sub 4}: no published pattern. Tetragonal U{sub 3}Te{sub 5}: three patterns 21--1407, 34--766 and 34--896 exit but all are of very poor quality. Phases which probably do not exist: Tetragonal UTe{sub 1.78}, Tetragonal UTe{sub 2}, Cubic UTe{sub 2} U{sub 3}Te{sub 7}(21--1402), U{sub 3}Te{sub 8}(21--1406).

Trends in radioisotope development and utilization in the United States

Energy Technology Data Exchange (ETDEWEB)

Mott, W E [Energy Research and Development Administration, Washington, D.C. (USA)

1976-06-01

The current trends in radioisotope and radiation technology in the United States are overviewed with emphasis on the developments since the 1973 Conference. The comments focus primarily on the research and development activities receiving the most attention today from the various agencies of the Government. Among the many available radionuclides, technetium-99m has played the single most important role for making possible the developments in the field of nuclear medicine. Many other short lived medium-lived nuclides are applied in the fields of nuclear medicine, cardiac pacemaker, artificial heart, and blood irradiator. Radiation processing is now firmly established in the United States. The trends in sewage treatment, polymer-impregnated materials, bioengineering, and food irradiation are reviewed. The programs for californium-252, strontium-90, cesium-137, plutonium-238, and krypton-85 are also reviewed. The author concludes this paper with the acknowledgement that Japanese researchers have contributed to and have been closely involved in many of the programs discussed. Of particular note is the participation in the clinical phase of the californium-252 radiotherapy program. Several Japanese hospitals have been cooperating with the United States since the very beginning of the californium-252 program in determining the value of the californium-252 neutron therapy. The research being performed is unique, and will contribute greatly to the decisions on the ultimate future of californium-252 for therapeutic purposes.

Mercury-Cadmium-Telluride Focal Plane Array Performance Under Non-Standard Operating Conditions

Science.gov (United States)

Richardson, Brandon S.; Eastwood, Michael L.; Bruce, Carl F.; Green, Robert O.; Coles, J. B.

2011-01-01

This paper highlights a new technique that allows the Teledyne Scientific & Imaging LLC TCM6604A Mercury-Cadmium-Telluride (MCT) Focal Plane Array (FPA) to operate at room temperature. The Teledyne MCT FPA has been a standard in Imaging Spectroscopy since its creation in the 1980's. This FPA has been used in applications ranging from space instruments such as CRISM, M3 and ARTEMIS to airborne instruments such as MaRS and the Next Generation AVIRIS Instruments1. Precise focal plane alignment is always a challenge for such instruments. The current FPA alignment process results in multiple cold cycles requiring week-long durations, thereby increasing the risk and cost of a project. These alignment cycles are necessary because optimal alignment is approached incrementally and can only be measured with the FPA and Optics at standard operating conditions, requiring a cold instrument. Instruments using this FPA are normally cooled to temperatures below 150K for the MCT FPA to properly function. When the FPA is run at higher temperatures the dark current increases saturating the output. This paper covers the prospect of warm MCT FPA operation from a theoretical and experimental perspective. We discuss the empirical models and physical laws that govern MCT material properties and predict the optimal settings that will result in the best MCT PA performance at 300K. Theoretical results are then calculated for the proposed settings. We finally present the images and data obtained using the actual system with the warm MCT FPA settings. The paper concludes by emphasizing the strong positive correlation between the measured values and the theoretical results.

The influence of reaction times on structural, optical and luminescence properties of cadmium telluride nanoparticles prepared by wet-chemical process

Energy Technology Data Exchange (ETDEWEB)

Kiprotich, Sharon, E-mail: KiprotichS@qwa.ufs.ac.za [Department of Physics, University of the Free State (QwaQwa campus), Private Bag X-13, Phuthaditjhaba 9866 (South Africa); Dejene, Francis B.; Ungula, Jatani [Department of Physics, University of the Free State (QwaQwa campus), Private Bag X-13, Phuthaditjhaba 9866 (South Africa); Onani, Martin O. [Departments of Chemistry, University of the Western Cape, Private Bag X17, Bellville 7535 (South Africa)

2016-01-01

This paper explains one pot synthesis of type II water soluble L-cysteine capped cadmium telluride (CdTe) core shell quantum dots using cadmium acetate, potassium tellurite and L-cysteine as the starting materials. The reaction was carried out in a single three necked flask without nitrogen under reflux at 100 °C. Results from PL show a sharp absorption excitonic band edge of the CdTe core with respect to the core shell which loses its shoulder during the growth of the shell on the core. The PL spectra indicate a drastic shift in emission window of the core which is simultaneously accompanied by an increase in emission intensity. X-ray diffraction pattern confirms the formation of hexagonal phase for all samples. Some difference in absorption edges were observed due to varying synthesis time of CdTe NPs. The position of the absorption band is observed to shift towards the lower wavelength side for shorter durations of synthesis.

A Fumonisins Immunosensor Based on Polyanilino-Carbon Nanotubes Doped with Palladium Telluride Quantum Dots

Science.gov (United States)

Masikini, Milua; Mailu, Stephen N.; Tsegaye, Abebaw; Njomo, Njagi; Molapo, Kerileng M.; Ikpo, Chinwe O.; Sunday, Christopher Edozie; Rassie, Candice; Wilson, Lindsay; Baker, Priscilla G. L.; Iwuoha, Emmanuel I.

2015-01-01

An impedimetric immunosensor for fumonisins was developed based on poly(2,5-dimethoxyaniline)-multi-wall carbon nanotubes doped with palladium telluride quantum dots onto a glassy carbon surface. The composite was assembled by a layer-by-layer method to form a multilayer film of quantum dots (QDs) and poly(2,5-dimethoxyaniline)-multi-wall carbon nanotubes (PDMA-MWCNT). Preparation of the electrochemical immunosensor for fumonisins involved drop-coating of fumonisins antibody onto the composite modified glassy carbon electrode. The electrochemical impedance spectroscopy response of the FB1 immunosensor (GCE/PT-PDMA-MWCNT/anti-Fms-BSA) gave a linear range of 7 to 49 ng L−1 and the corresponding sensitivity and detection limits were 0.0162 kΩ L ng−1 and 0.46 pg L−1, respectively, hence the limit of detection of the GCE/PT-PDMA-MWCNT immunosensor for fumonisins in corn certified material was calculated to be 0.014 and 0.011 ppm for FB1, and FB2 and FB3, respectively. These results are lower than those obtained by ELISA, a provisional maximum tolerable daily intake (PMTDI) for fumonisins (the sum of FB1, FB2, and FB3) established by the Joint FAO/WHO expert committee on food additives and contaminants of 2 μg kg−1 and the maximum level recommended by the U.S. Food and Drug Administration (FDA) for protection of human consumption (2–4 mg L−1). PMID:25558993

Pre-chemotherapy values for left and right ventricular volumes and ejection fraction by gated tomographic radionuclide angiography using a cadmium-zinc-telluride detector gamma camera

DEFF Research Database (Denmark)

Haarmark, Christian; Haase, Christine; Jensen, Maria Maj

2016-01-01

age and both left and right ventricular volumes in women (r = -0.4, P right end systolic ventricular volume in men (r = -0.3, P = .001). CONCLUSION: A set of reference values for cardiac evaluation prior to chemotherapy in cancer patients without other known cardiopulmonary......BACKGROUND: Estimation of left ventricular ejection fraction (LVEF) using equilibrium radionuclide angiography is an established method for assessment of left ventricular function. The purpose of this study was to establish normative data on left and right ventricular volumes and ejection fraction......, using cadmium-zinc-telluride SPECT camera. METHODS AND RESULTS: From routine assessments of left ventricular function in 1172 patients, we included 463 subjects (194 men and 269 women) without diabetes, previous potentially cardiotoxic chemotherapy, known cardiovascular or pulmonary disease. The lower...

Preparation and study of the properties of lead telluride and cadmium telluride diodes for use in nuclear spectrometry; Preparation et etude des proprietes de diodes au tellurure de plomb et au tellurure de cadmium en vue d'une utilisation en spectrometrie nucleaire

Energy Technology Data Exchange (ETDEWEB)

Lancon, R [Commissariat a l' Energie Atomique, Grenoble (France). Centre d' Etudes Nucleaires

1969-07-01

This work studies the possibility of using high atomic number compound semiconductors, like lead telluride and cadmium telluride as to realize nuclear radiation detectors, specially in gamma ray spectrometry because of their high absorption coefficient. The problems related to the preparation of binary compounds are exposed. Experiments on PbTe show the influence of the conditions of preparation on the electrical properties of the semiconductor which are greatly dependent on the stoichiometry of the compound. PbTe surface-barrier diodes were realized and have been used to study the surface properties of this semiconductor. These diodes cannot detect nuclear radiations because of the too weak resistivity of our material. Different types of devices made of Cd Te have been studied. One of these diodes has been used as an alpha particle detector. We explain the relative poor performances of that detector by the presence of lattice defects in Cd Te where charge carriers may recombine themselves. By analysing the properties of gold diffused Cd Te diodes we identified this defect, the cadmium vacancy, the presence of which is due to the deviation from stoichiometry during the preparation of the material. (author) [French] Ce travail etudie la possibilite d'utiliser des semiconducteurs composes d'elements a numero atomique eleve, tels que le tellurure de plomb et le tellurure de cadmium pour la realisation de detecteurs de rayonnements nucleaires, grace notamment a la section efficace de capture elevee qu'ils presentent vis-a-vis des rayons gamma. On souligne les problemes relatifs a la preparation des composes binaires. Les experiences realisees sur PbTe mettent en evidence l'influence des conditions de preparation sur les proprietes electriques du semiconducteur qui dependent fortement de la stoechiometrie du compose. Nous avons realise des diodes au PbTe a barriere de surface qui ont permis de preciser les proprietes de surface de ce semiconducteur. La trop faible

Structure data of elements and intermetallic phases. SubVol. B. Sulfides, selenides, tellurides. Pt. 1. Ag-Al-Cd-S. Cu-Te-Yb

Energy Technology Data Exchange (ETDEWEB)

Hellwege, K H; Hellwege, A M [eds.; Eisenmann, B; Schaefer, H

1986-01-01

Volume III/14 'Structure data of elements and intermetallic phases' is a supplement to and extension of Volume III/6. Since the publication of III/6 in 1971 (considering original papers up to 1967), the amount of new information for these substances has increased rapidly. Therefore the data had to be divided into several parts. The first part, III/14b1, is presented herewith. In Volume III/6, simple sulfides, selenides and tellurides were treated together with the intermetallic phases. The data are compiled in the same way as in III/6: for each substance the space group, lattice constants, their dependence on temperature and pressure, and other information is listed in the tables. In several cases, mostly for solid solutions, diagrams are given which are added in a separate chapter. Original papers containing a complete structure analysis are referred to in the tables. (orig./GSCH).

CsAg{sub 5}Te{sub 3}: a new metal-rich telluride with a unique tunnel structure

Energy Technology Data Exchange (ETDEWEB)

Jing, Li [Rutgers Univ., Camden, NJ (United States). Dept. of Chem.; Hongyou, Guo [Rutgers Univ., Camden, NJ (United States). Dept. of Chem.; Xiang, Zhang [Michigan State Univ., East Lansing, MI (United States). Dept. of Chemistry; Kanatzidis, M G [Michigan State Univ., East Lansing, MI (United States). Dept. of Chemistry

1995-02-15

The synthesis and structure of a new ternary silver telluride, CsAg{sub 5}Te{sub 3}, is described. The compound was prepared from a Cs{sub 2}Te-CaTe-Te flux but it can also be prepared from a direct combination of Cs{sub 2}Te and Ag{sub 2}Te under vacuum at 600 C. The crystal data for CsAg{sub 5}Te{sub 3} at 20 C (Mo K{alpha} radiation) are as follows: a=14.672(2) A and c=4.601(3) A; V=990.5(8) A{sup 3}; Z=4; D{sub calc}=7.075 g cm{sup -3}; space group, P4{sub 2} /mnm (No. 136); 2{theta}{sub max}=50 ; number of independent data collected, 572; number of data observed with I>3{sigma}(I), 267; number of variables, 32; {mu}=218.51 cm{sup -1}; extinction coefficient, 0.585x10{sup -7}; final R=0.040; R{sub w}=0.046; goodness of fit, 1.42. The compound features a new structure type with Cs{sup +}-filled, relatively large tunnels running through the lattice. The material is a semiconductor with a band gap of about 0.65 eV. ((orig.))

Diagnostic performance of a novel cadmium-zinc-telluride gamma camera system assessed using fractional flow reserve.

Science.gov (United States)

Tanaka, Hirokazu; Chikamori, Taishiro; Tanaka, Nobuhiro; Hida, Satoshi; Igarashi, Yuko; Yamashita, Jun; Ogawa, Masashi; Shiba, Chie; Usui, Yasuhiro; Yamashina, Akira

2014-01-01

Although the novel cadmium-zinc-telluride (CZT) camera system provides excellent image quality, its diagnostic value using thallium-201 as assessed on coronary angiography (CAG) and fractional flow reserve (FFR) has not been validated. METHODS AND RESULTS: To evaluate the diagnostic accuracy of the CZT ultrafast camera system (Discovery NM 530c), 95 patients underwent stress thallium-201 single-photon emission computed tomography (SPECT) and then CAG within 3 months. Image acquisition was performed in the supine and prone positions after stress for 5 and 3 min, respectively, and in the supine position at rest for 10 min. Significant stenosis was defined as ≥90% diameter narrowing on visual estimation, or a lesion with <90% and ≥50% stenosis and FFR ≤0.75. To detect individual coronary stenosis, the respective sensitivity, specificity, and accuracy were 90%, 64%, and 78% for left anterior descending coronary artery stenosis, 78%, 84%, and 81% for left circumflex stenosis, and 83%, 47%, and 60% for right coronary artery (RCA) stenosis. The combination of prone and supine imaging had a higher specificity for RCA disease than supine imaging alone (65% vs. 47%), with an improvement in accuracy from 60% to 72%. Using thallium-201 with short acquisition time, combined with prone imaging, CZT SPECT had a high diagnostic yield in detecting significant coronary stenosis as assessed using FFR.

Growth of Bi doped cadmium zinc telluride single crystals by Bridgman oscillation method and its structural, optical, and electrical analyses

International Nuclear Information System (INIS)

Carcelen, V.; Rodriguez-Fernandez, J.; Dieguez, E.; Hidalgo, P.

2010-01-01

The II-VI compound semiconductor cadmium zinc telluride (CZT) is very useful for room temperature radiation detection applications. In the present research, we have successfully grown Bi doped CZT single crystals with two different zinc concentrations (8 and 14 at. %) by the Bridgman oscillation method, in which one experiment has been carried out with a platinum (Pt) tube as the ampoule support. Pt also acts as a cold finger and reduces the growth velocity and enhances crystalline perfection. The grown single crystals have been studied with different analysis methods. The stoichiometry was confirmed by energy dispersive by x-ray and inductively coupled plasma mass spectroscopy analyses and it was found there is no incorporation of impurities in the grown crystal. The presence of Cd and Te vacancies was determined by cathodoluminescence studies. Electrical properties were assessed by I-V analysis and indicated higher resistive value (8.53x10 8 Ω cm) for the crystal grown with higher zinc concentration (with Cd excess) compare to the other (3.71x10 5 Ω cm).

Reaction of 1-bromo-3-chloropropane with tellurium and dimethyl telluride in the system of hydrazine hydrate-alkali; Reaktsiya 1-brom-3-khlorpropana s tellurom i dimetilditelluridom v sisteme gidrazin-gidrat-shcheloch'

Energy Technology Data Exchange (ETDEWEB)

Russavskaya, N V; Levanova, E P; Sukhomazova, Eh N; Grabel' nykh, V A; Elaev, A V; Klyba, L V; Zhanchipova, E R; Albanov, A I; Korotaeva, I M; Toryashinova, D S.D.; Korchevin, N A [SO RAN, Irkutskij Inst. Khimii imeni A.E. Favorskogo, Irkutsk (Russian Federation)

2006-05-15

A synthesis of oligomeric substance of thiocol type, the poly(trimethyleneditelluride), from 1-bromo-3-chloropropane and elemental tellurium is performed using a hydrazine hydrate-alkali system. Reductive splitting of the tellurocol followed by alkylation with methyl iodide give rise to preparation of bis(methyltelluro)propane, which was synthesized also from dimethyl telluride and 1,3-dihalopropanes using the N{sub 2}H{sub 4}{center_dot}H{sub 2}O/KOH system. The reaction products were characterized by elementary analysis, NMR, and IR spectra. Mass spectra of the synthesized low molecular weight organotellurium compounds are considered.

Manganese determination om minerals by activation analysis, using the californium-252 as a neutron source; Determinacao de manganes em minerios, por analise por ativacao, usando californio-252 como fonte de neutrons

Energy Technology Data Exchange (ETDEWEB)

Cardoso, Antonio

1976-07-01

Neutron Activation Analysis, using a Californium-252 neutron source, has been applied for the determination of manganese in ores such as pyrolusite, rodonite (manganese silicate)' and blending used in dry-batteries The favorable nuclear properties of manganese, such as high thermal neutron cross-section for the reaction {sup 55}Mn (n.gamma){sup 56} Mn, high concentration of manganese in the matrix and short half - life of {sup 56}Mn, are an ideal combination for non-destructive analysis of manganese in ores. Samples and standards of manganese dioxide were irradiated for about 20 minutes, followed by a 4 to 15 minutes decay and counted in a single channel pulse-height discrimination using a NaI(Tl) scintillation detector. Counting time was equal to 10 minutes. The interference of nuclear reactions {sup 56}Fe(n,p){sup 56}Mn and {sup 59} Co (n, {alpha}){sup 56} were studied, as well as problems in connection with neutron shadowing during irradiation, gamma-rays attenuation during counting and influence of granulometry of samples. One sample,was also analysed by wet-chemical method (sodium bismuthate) in order to compare results. As a whole, i t was shown that the analytical method of neutron activation for manganese in ores and blending, is a method simple, rapid and with good precision and accuracy. (author)

Manganese determination om minerals by activation analysis, using the californium-252 as a neutron source; Determinacao de manganes em minerios, por analise por ativacao, usando californio-252 como fonte de neutrons

Energy Technology Data Exchange (ETDEWEB)

Cardoso, Antonio

1976-07-01

Neutron Activation Analysis, using a Californium-252 neutron source, has been applied for the determination of manganese in ores such as pyrolusite, rodonite (manganese silicate)' and blending used in dry-batteries The favorable nuclear properties of manganese, such as high thermal neutron cross-section for the reaction {sup 55}Mn (n.gamma){sup 56} Mn, high concentration of manganese in the matrix and short half - life of {sup 56}Mn, are an ideal combination for non-destructive analysis of manganese in ores. Samples and standards of manganese dioxide were irradiated for about 20 minutes, followed by a 4 to 15 minutes decay and counted in a single channel pulse-height discrimination using a NaI(Tl) scintillation detector. Counting time was equal to 10 minutes. The interference of nuclear reactions {sup 56}Fe(n,p){sup 56}Mn and {sup 59} Co (n, {alpha}){sup 56} were studied, as well as problems in connection with neutron shadowing during irradiation, gamma-rays attenuation during counting and influence of granulometry of samples. One sample,was also analysed by wet-chemical method (sodium bismuthate) in order to compare results. As a whole, i t was shown that the analytical method of neutron activation for manganese in ores and blending, is a method simple, rapid and with good precision and accuracy. (author)

Comparison of Cadmium-Zinc-Telluride semiconductor and Yttrium-Aluminum-Perovskite scintillator as photon detectors for epithermal neutron spectroscopy

International Nuclear Information System (INIS)

Tardocchi, M.; Pietropaolo, A.; Andreani, C.; Gorini, G.; Imberti, S.; Perelli-Cippo, E.; Senesi, R.; Rhodes, N.; Schooneveld, E.M.

2006-01-01

The range of applications of epithermal neutron scattering experiments has been recently extended by the development of the Resonance Detector. In a Resonance Detector, resonant neutron absorption in an analyzer foil results in prompt emission of X- and γ-rays which are detected by a photon counter. Several combinations of analyzer foils and photon detectors have been studied and tested over the years and best results have been obtained with the combination of a natural uranium and (i) Cadmium-Zinc-Telluride (CZT) semiconductor (ii) Yttrium-Aluminum-Perovskite (YAP) scintillators. Here we compare the performance of the CZT semiconductor and YAP scintillator as Resonance Detector units. Two Resonance Detector prototypes made of natural uranium foil viewed by CZT and YAP were tested on the VESUVIO spectrometer at the ISIS spallation neutron source. The results show that both YAP and CZT can be used to detect epithermal neutrons in the energy range from 1 up to 66 eV. It was found that the signal-to-background ratio of the measurement can significantly be improved by raising the lower level discrimination threshold on the γ energy to about 600 keV. The advantages/disadvantages of the choice of a Resonance Detector based on YAP or CZT are discussed together with some potential applications

Source storage and transfer cask: Users Guide

International Nuclear Information System (INIS)

Eccleston, G.W.; Speir, L.G.; Garcia, D.C.

1985-04-01

The storage and shield cask for the dual californium source is designed to shield and transport up to 3.7 mg (2 Ci) of 252 Cf. the cask meets Department of Transportation (DOT) license requirements for Type A materials (DOT-7A). The cask is designed to transfer sources to and from the Flourinel and Fuel Storage (FAST) facility delayed-neutron interrogator. Californium sources placed in the cask must be encapsulated in the SR-CF-100 package and attached to Teleflex cables. The cask contains two source locations. Each location contains a gear box that allows a Teleflex cable to be remotely moved by a hand crank into and out of the cask. This transfer procedure permits sources to be easily removed and inserted into the delayed-neutron interrogator and reduces personnel radiation exposure during transfer. The radiation dose rate with the maximum allowable quantity of californium (3.7 mg) in the cask is 30 mR/h at the surface and less than 2 mR/h 1 m from the cask surface. This manual contains information about the cask, californium sources, describes the method to ship the cask, and how to insert and remove sources from the cask. 28 figs

Regulatory policy governing cadmium-telluride photovoltaics: A case study contrasting life cycle management with the precautionary principle

International Nuclear Information System (INIS)

Sinha, Parikhit; Kriegner, Christopher J.; Schew, William A.; Kaczmar, Swiatoslav W.; Traister, Matthew; Wilson, David J.

2008-01-01

Market projections for cadmium-telluride (CdTe) thin-film photovoltaics (PV) are tempered by global environmental policies based on the precautionary principle which restrict electronic products containing cadmium, a known human carcinogen. An alternative to the precautionary principle is life cycle management, which involves manufacturers assuming product stewardship from beginning to end of product life. Both approaches have the aim of minimizing environmental contamination, but attempt to do so in different ways. Restrictions on electronic products containing cadmium by the precautionary principle-based restriction of hazardous substances (RoHS) directive in the European Union and a similar policy in China are presented, relative to their potential impact on CdTe PV. Life cycle environmental risks with respect to potential release of cadmium to the environment are also presented for routine operation of CdTe PV panels, potential catastrophic release of cadmium from a residential fire, and at the end of the product life. There is negligible risk of environmental cadmium contamination during routine operation and insignificant risk during catastrophic exposure events such as fire. At the end of the product life, risks of contamination are minimized by take-back programs that may be paid for by insurance premiums incorporated into the cost of the product. Therefore, policies based on the precautionary principle that could potentially ban the product based on its cadmium content may not be warranted

Regulatory policy governing cadmium-telluride photovoltaics: A case study contrasting life cycle management with the precautionary principle

Energy Technology Data Exchange (ETDEWEB)

Sinha, Parikhit; Kriegner, Christopher J.; Schew, William A.; Kaczmar, Swiatoslav W.; Traister, Matthew; Wilson, David J. [O' Brien and Gere, Ecological Sciences, E. 512 Township Line Road, Two Valley Square, Suite 120, Blue Bell, PA 19422 (United States)

2008-01-15

Market projections for cadmium-telluride (CdTe) thin-film photovoltaics (PV) are tempered by global environmental policies based on the precautionary principle which restrict electronic products containing cadmium, a known human carcinogen. An alternative to the precautionary principle is life cycle management, which involves manufacturers assuming product stewardship from beginning to end of product life. Both approaches have the aim of minimizing environmental contamination, but attempt to do so in different ways. Restrictions on electronic products containing cadmium by the precautionary principle-based restriction of hazardous substances (RoHS) directive in the European Union and a similar policy in China are presented, relative to their potential impact on CdTe PV. Life cycle environmental risks with respect to potential release of cadmium to the environment are also presented for routine operation of CdTe PV panels, potential catastrophic release of cadmium from a residential fire, and at the end of the product life. There is negligible risk of environmental cadmium contamination during routine operation and insignificant risk during catastrophic exposure events such as fire. At the end of the product life, risks of contamination are minimized by take-back programs that may be paid for by insurance premiums incorporated into the cost of the product. Therefore, policies based on the precautionary principle that could potentially ban the product based on its cadmium content may not be warranted. (author)

Radionuclides in rodents

International Nuclear Information System (INIS)

Taylor, G.N.

1985-01-01

Studies are being conducted in mice comparing the toxicity of radium-226, plutonium-239, americium-241, californium-249 and californium-252 in C57B1/Do (albino) mice and the toxicity of americium-241, plutonium-239 and radium-226 in deer mice (Peromyscus maniculatus) and grasshopper mice (Onychomys leucogaster). These experiments will ultimately enable comparison of the toxicity of the above actinide toxicity in man to be made using radium toxicity as the baseline

Indium telluride nanotubes: Solvothermal synthesis, growth mechanism, and properties

Energy Technology Data Exchange (ETDEWEB)

Zhou, Liyan [National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China); Yan, Shancheng, E-mail: yansc@njupt.edu.cn [National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China); School of Geography and Biological Information, Nanjing University of Posts and Telecommunications, Nanjing 210046 (China); Lu, Tao; Shi, Yi; Wang, Jianyu [National Laboratory of Solid State Microstructures, School of Electronic Science and Engineering, Nanjing University, Nanjing 210093 (China); Yang, Fan [School of Geography and Biological Information, Nanjing University of Posts and Telecommunications, Nanjing 210046 (China)

2014-03-15

hydrogen storage, compared with the nanowires. The nanotube device also has a broad light detection range from 300 nm to 1100 nm, covering the UV–visible–NIR region. This good performance of In{sub 2}Te{sub 3} nanotubes may enable significant advancements of new photodetection and photosensing applications. Highlights: • The In{sub 2}Te{sub 3} nanotube device also has a broad light detection range from 300 nm to 1100 nm. • The nanotube is 137.85 m{sup 2} g{sup −1}, which makes it suitable for gas sensing and hydrogen storage. • A possible growth mechanism of the indium telluride nanotubes was proposed. • In addition, no In{sub 2}Te{sub 3} nanotubes have been reported until now.

Solution synthesis of telluride-based nano-barbell structures coated with PEDOT:PSS for spray-printed thermoelectric generators

Science.gov (United States)

Bae, Eun Jin; Kang, Young Hun; Jang, Kwang-Suk; Lee, Changjin; Cho, Song Yun

2016-05-01

Solution-processable telluride-based heterostructures coated with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (Te-Bi2Te3/PEDOT:PSS) were synthesized through a solution-phase reaction at low temperatures. The water-based synthesis yielded PEDOT:PSS-coated Te-Bi2Te3 nano-barbell structures with a high Seebeck coefficient that can be stably dispersed in water. These hybrid solutions were deposited onto a substrate by the spray-printing method to prepare thermoelectric generators. The thermoelectric properties of the Te-Bi2Te3/PEDOT:PSS hybrid films were significantly enhanced by a simple acid treatment due to the increased electrical conductivity, and the power factor of those materials can be effectively tuned over a wide range depending on the acid concentration of the treatment. The power factors of the synthesized Te-Bi2Te3/PEDOT:PSS hybrids were optimized to 60.05 μW m-1 K-2 with a Seebeck coefficient of 93.63 μV K-1 and an electrical conductivity of 69.99 S cm-1. The flexible thermoelectric generator fabricated by spray-printing Te-Bi2Te3/PEDOT:PSS hybrid solutions showed an open-circuit voltage of 1.54 mV with six legs at ΔT = 10 °C. This approach presents the potential for realizing printing-processable hybrid thermoelectric materials for application in flexible thermoelectric generators.Solution-processable telluride-based heterostructures coated with poly(3,4-ethylenedioxythiophene):poly(styrenesulfonate) (Te-Bi2Te3/PEDOT:PSS) were synthesized through a solution-phase reaction at low temperatures. The water-based synthesis yielded PEDOT:PSS-coated Te-Bi2Te3 nano-barbell structures with a high Seebeck coefficient that can be stably dispersed in water. These hybrid solutions were deposited onto a substrate by the spray-printing method to prepare thermoelectric generators. The thermoelectric properties of the Te-Bi2Te3/PEDOT:PSS hybrid films were significantly enhanced by a simple acid treatment due to the increased electrical conductivity, and

Spectroscopic, microscopic, and internal stress analysis in cadmium telluride grown by close-space sublimation

International Nuclear Information System (INIS)

Manciu, Felicia S.; Salazar, Jessica G.; Diaz, Aryzbe; Quinones, Stella A.

2015-01-01

High quality materials with excellent ordered structure are needed for developing photovoltaic and infrared devices. With this end in mind, the results of our research prove the importance of a detailed, comprehensive spectroscopic and microscopic analysis in assessing cadmium telluride (CdTe) characteristics. The goal of this work is to examine not only material crystallinity and morphology, but also induced stress in the deposit material. A uniform, selective growth of polycrystalline CdTe by close-space sublimation on patterned Si(111) and Si(211) substrates is demonstrated by scanning electron microscopy images. Besides good crystallinity of the samples, as revealed by both Raman scattering and Fourier transform infrared absorption investigations, the far-infrared transmission data also show the presence of surface optical phonon modes, which is direct evidence of confinement in such a material. The qualitative identification of the induced stress was achieved by performing confocal Raman mapping microscopy on sample surfaces and by monitoring the existence of the rock-salt and zinc-blende structural phases of CdTe, which were associated with strained and unstrained morphologies, respectively. Although the induced stress in the material is still largely due to the high lattice mismatch between CdTe and the Si substrate, the current results provide a direct visualization of its partial release through the relaxation effect at crystallite boundaries and of preferential growth directions of less strain. Our study, thus offers significant value for improvement of material properties, by targeting the needed adjustments in the growth processes. - Highlights: • Assessing the characteristics of CdTe deposited on patterned Si substrates • Proving the utility of confocal Raman microscopy in monitoring the induced stress • Confirming the partial stress release through the grain boundary relaxation effect • Demonstrating the phonon confinement effect in low

Quantum-chemical consideration of extermal valent forms of actinides

International Nuclear Information System (INIS)

Ionova, G.V.; Pershina, V.G.; Spitsyn, V.I.

1982-01-01

Stability of valent forms of actinides that has not yet studied experimentally, is considered within the framework of quantum-chemical considerations. Oxidizing potentials E 0 for actinide elements are determined theoretically. A dependence of the definite valent state stability on relativistic effect is shown. A conclusion is made that oxidizing potential E 0 (4-5) for americium should be higher than E 0 (4-5) for plutonium. A relatively small oxidizing potential E 0 (4-5) for curium speaks about principle possibility of production of five-valent curium in solution, though it is less stable than the six-valent one. Oxidizing potential corresponding to transition of three-valent californium into the four-valent state should be less than the value adopted in literature. A relatively small oxidizing potential of californium E 0 (4-5) speaks about possible existence of five-valent californium in solution

Design of a homogeneous subcritical nuclear reactor based on thorium with a source of californium 252; Diseno de un reactor nuclear subcritico homogeneo a base de Torio con una fuente de Californio 252

Energy Technology Data Exchange (ETDEWEB)

Delgado H, C. E.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidad Academica de Estudios Nucleares, Cipres No. 10, Fracc. La Penuela, 98068 Zacatecas, Zac. (Mexico); Sajo B, L., E-mail: ce_delgado89@hotmail.com [Universidad Simon Bolivar, Laboratorio de Fisica Nuclear, Apdo. 89000, 1080A Caracas (Venezuela, Bolivarian Republic of)

2015-10-15

Full text: One of the energy alternatives to fossil fuels which do not produce greenhouse gases is the nuclear energy. One of the drawbacks of this alternative is the generation of radioactive wastes of long half-life and its relation to the generation of nuclear materials to produce weapons of mass destruction. An option to these drawbacks of nuclear energy is to use Thorium as part of the nuclear fuel which it becomes in U{sup 233} when capturing neutrons, that is a fissile material. In this paper Monte Carlo methods were used to design a homogeneous subcritical reactor based on thorium. As neutron reflector graphite was used. The reactor core is homogeneous and is formed of 70% light water as moderator, 12% of enriched uranium UO{sub 2}(NO{sub 3}){sub 4} and 18% of thorium Th(NO{sub 3}){sub 4} as fuel. To start the nuclear fission chain reaction an isotopic source of californium 252 was used with an intensity of 4.6 x 10{sup 7} s{sup -1}. In the design the value of the effective multiplication factor, whose value turned out k{sub eff} <1 was calculated. Also, the neutron spectra at different distances from the source and the total fluence were calculated, as well as the values of the ambient dose equivalent in the periphery of the reactor. (Author)

Material properties of large-volume cadmium zinc telluride crystals and their relationship to nuclear detector performance

International Nuclear Information System (INIS)

James, R.B.; Lund, J.; Yoon, H.

1997-01-01

The material showing the greatest promise today for production of large-volume gamma-ray spectrometers operable at room temperature is cadmium zinc telluride (CZT). Unfortunately, because of deficiencies in the quality of the present material, high-resolution CZT spectrometers have thus far been limited to relatively small dimensions, which makes them inefficient at detecting high photon energies and ineffective for weak radiation signals except in near proximity. To exploit CZT fully, it will be necessary to make substantial improvements in the material quality. Improving the material involves advances in the purity, crystallinity, and control of the electrical compensation mechanism. Sandia National Laboratories, California, in close collaboration with US industry and academia, has initiated efforts to develop a detailed understanding of the underlying material problems limiting the performance of large volume gamma-ray spectrometers and to overcome them through appropriate corrections therein. A variety of analytical and numerical techniques are employed to quantify impurities, compositional and stoichiometric variations, crystallinity, strain, bulk and surface defect states, carrier mobilities and lifetimes, electric field distributions, and contact chemistry. Data from these measurements are correlated with spatial maps of the gamma-ray and alpha particle spectroscopic response to determine improvements in the material purification, crystal growth, detector fabrication, and surface passivation procedures. The results of several analytical techniques will be discussed. The intended accomplishment of this work is to develop a low-cost, high-efficiency CZT spectrometer with an active volume of 5 cm 3 and energy resolution of 1--2% (at 662 keV), which would give the US a new field capability for screening radioactive substances

Investigations of portable cadmium telluride (CdTe(Cl)) detectors for clinical studies with radioactive indicators

International Nuclear Information System (INIS)

Bojsen, J.

1985-01-01

The combination of small, portable γ-radiation-sensitive Cadmium Telluride (CdTE(Cl)) crystal detectors and portable solid state data storage memories makes it feasible to extend the measuring period in a number of clinical investigations based on the use of various radioisotopes and external detection. Blood sampling can be avoided in some cases. Continuous ambulatory monitoring of relevant physiological parameters is practicable, e.g. kidney function (GFR), left ventricular ejection fraction, subcutaneous blood flow, muscle blood flow and insulin absorption in diabetic patients. In the present methodological study the applicability of the 133-Xe washout technique to subcutaneous (s.c.) adipose tissue blood flow (SBF) has been investigated and adapted to the use of CdTe(Cl) detectors attached to the skin surface for the measurement of local 133-Xe-disappearance rate constants (k). Physical characterization of CdTe(Cl) detectors as γ-sensitive devices has been performed, and adequate counting sensitivities were found without detector energy-resolution properties. The CdTe(Cl) detectors are therefore suitable for single indicator studies. The measuring geometry of CdTe(Cl) detectors was studied and compared with that of stationary Sodium Iodide (NaI(Tl)) detectors in both phantom and in vivo investigations. The spatial properties of CdTe(Cl) detectors could to some extent be adjusted by pulse height discrimination and lead collimation. When long-term measurements were complicated by for instance physical activity of the patients, the small CdTe(Cl) detectors in general showed equal or better performance than the heavy and voluminous NaI(Tl) detectors. The free movement of the ambulatory patient and the avoidance of cable connections to stationary data-collecting systems gave improved possibilities for measurements of the relevant parameters. From this point of view, portable CdTe(Cl) detectors must be considered an important advance for radioactivity studies in

Irradiation-induced doping of Bismuth Telluride Bi2Te3

International Nuclear Information System (INIS)

Rischau, Carl Willem

2014-01-01

Bismuth Telluride Bi 2 Te 3 has attracted enormous attention because of its thermoelectric and topological insulator properties. Regarding its bulk band structure Bi 2 Te 3 is a band insulator with an energy gap of around 150-170 meV. However, the native anti-site defects that are present in real samples always dope this band insulator and shift the chemical potential into the valence or conduction band. In this PhD, the Fermi surface of as-grown and electron irradiated p-type Bi 2 Te 3 single crystals has been investigated extensively using electrical transport experiments. For moderate hole concentrations (p ∼< 5 x 10 18 cm -3 ), it is confirmed that electrical transport can be explained by a six-valley model and the presence of strong Zeeman-splitting. At high doping levels (p≅5 x 10 18 cm -3 ), the hole concentrations determined from Hall and Shubnikov-de Haas (SdH) effect differ significantly which is attributed to an impurity/defect band introduced by the anti-site defects. In this work, we show that it is possible to dope p-type Bi 2 Te 3 in a very controlled manner using electron-irradiation by performing detailed in- and ex-situ electrical transport studies on samples irradiated at room and at low temperatures with 2.5 MeV electrons. These studies show that the defects induced at both irradiation temperatures act as electron donors and can thus be used to convert the conduction from p- to n-type. The point of optimal compensation is accompanied by an increase of the low-temperature resistivity by several orders of magnitude. Irradiation at room temperature showed that both the p-type samples obtained after irradiation to intermediate doses as well as the samples in which the conduction has been converted to n-type by irradiation, still have a well defined Fermi surface as evidenced by SdH oscillations. By studying the Hall coefficient in-situ during low temperature electron irradiation, the coexistence of electron- and hole-type carriers was evidenced

Material properties of large-volume cadmium zinc telluride crystals and their relationship to nuclear detector performance

Energy Technology Data Exchange (ETDEWEB)

James, R.B.; Lund, J. [Sandia National Labs., Livermore, CA (United States); Yoon, H. [Sandia National Labs., Livermore, CA (United States)]|[Univ. of California, Los Angeles, CA (United States)] [and others

1997-09-01

The material showing the greatest promise today for production of large-volume gamma-ray spectrometers operable at room temperature is cadmium zinc telluride (CZT). Unfortunately, because of deficiencies in the quality of the present material, high-resolution CZT spectrometers have thus far been limited to relatively small dimensions, which makes them inefficient at detecting high photon energies and ineffective for weak radiation signals except in near proximity. To exploit CZT fully, it will be necessary to make substantial improvements in the material quality. Improving the material involves advances in the purity, crystallinity, and control of the electrical compensation mechanism. Sandia National Laboratories, California, in close collaboration with US industry and academia, has initiated efforts to develop a detailed understanding of the underlying material problems limiting the performance of large volume gamma-ray spectrometers and to overcome them through appropriate corrections therein. A variety of analytical and numerical techniques are employed to quantify impurities, compositional and stoichiometric variations, crystallinity, strain, bulk and surface defect states, carrier mobilities and lifetimes, electric field distributions, and contact chemistry. Data from these measurements are correlated with spatial maps of the gamma-ray and alpha particle spectroscopic response to determine improvements in the material purification, crystal growth, detector fabrication, and surface passivation procedures. The results of several analytical techniques will be discussed. The intended accomplishment of this work is to develop a low-cost, high-efficiency CZT spectrometer with an active volume of 5 cm{sup 3} and energy resolution of 1--2% (at 662 keV), which would give the US a new field capability for screening radioactive substances.

Myocardial perfusion imaging with a cadmium zinc telluride-based gamma camera versus invasive fractional flow reserve

Energy Technology Data Exchange (ETDEWEB)

Mouden, Mohamed [Isala klinieken, Department of Cardiology, Zwolle (Netherlands); Isala klinieken, Department of Nuclear Medicine, Zwolle (Netherlands); Ottervanger, Jan Paul; Timmer, Jorik R. [Isala klinieken, Department of Cardiology, Zwolle (Netherlands); Knollema, Siert; Reiffers, Stoffer; Oostdijk, Ad H.J.; Jager, Pieter L. [Isala klinieken, Department of Nuclear Medicine, Zwolle (Netherlands); Boer, Menko-Jan de [University Medical Centre Nijmegen, Department of Cardiology, Nijmegen (Netherlands)

2014-05-15

Recently introduced ultrafast cardiac SPECT cameras with cadmium zinc telluride-based (CZT) detectors may provide superior image quality allowing faster acquisition with reduced radiation doses. Although the level of concordance between conventional SPECT and invasive fractional flow reserve (FFR) measurement has been studied, that between FFR and CZT-based SPECT is not yet known. Therefore, we aimed to assess the level of concordance between CZT SPECT and FFR in a large patient group with stable coronary artery disease. Both invasive FFR and myocardial perfusion imaging with a CZT-based SPECT camera, using Tc-tetrofosmin as tracer, were performed in 100 patients with stable angina and intermediate grade stenosis on invasive coronary angiography. A cut-off value of <0.75 was used to define abnormal FFR. The mean age of the patients was 64 ± 11 years, and 64 % were men. SPECT demonstrated ischaemia in 31 % of the patients, and 20 % had FFR <0.75. The concordance between CZT SPECT and FFR was 73 % on a per-patient basis and 79 % on a per-vessel basis. Discordant findings were more often seen in older patients and were mainly (19 %) the result of ischaemic SPECT findings in patients with FFR ≥0.75, whereas only 8 % had an abnormal FFR without ischaemia as demonstrated by CZT SPECT. Only 20 - 30 % of patients with intermediate coronary stenoses had significant ischaemia as assessed by CZT SPECT or invasive FFR. CZT SPECT showed a modest degree of concordance with FFR, which is comparable with previous results with conventional SPECT. Further investigations are particularly necessary in patients with normal SPECT and abnormal FFR, especially to determine whether these patients should undergo revascularization. (orig.)

Enhanced thermoelectric properties of metal film on bismuth telluride-based materials

International Nuclear Information System (INIS)

Chao, Wen Hsuan; Chen, Yi Ray; Tseng, Shih Chun; Yang, Ping Hsing; Wu, Ren Jye; Hwang, Jenn Yeu

2014-01-01

Diffusion barriers have a significant influence on the reliability and life time of thermoelectric modules. Although nickel is commonly used as a diffusion barrier in commercial thermoelectric modules, several studies have verified that Ni migrates to bismuth telluride-based material during high temperature cycles and causes a loss in efficacy. In this paper, the influence of metal layers coated to p-type and n-type Bi 2 Te 3 on the interface characterization and thermoelectric property is studied using a RF magnetron sputtering. The findings from this study demonstrate the structural and thermoelectric properties of p-type and n-type Bi 2 Te 3 coated with different metal layers. The crystalline phase and compositional change of the interface between the Bi 2 Te 3 materials and the metal layers were determined using an X-ray diffractometer and scanning electron microscopy with energy dispersive spectroscopy. Formation of NiTe was observed in the sample of Ni/p-type Bi 2 Te 3 based films post-annealed in an N 2 atmosphere at 200 °C. In contrast, no Co x Te y was formed in the sample of Co/p-type Bi 2 Te 3 based films post-annealed at 200 °C. For as-deposited Ni/p-type and n-type Bi 2 Te 3 based legs, the Ni slightly diffused into the Bi 2 Te 3 based legs. A similar phenomenon also occurred in the as-deposited Co/p-type and n-type Bi 2 Te 3 based legs. The Seebeck coefficients of the Co contacts on the Bi 2 Te 3 based material displayed better behavior than those of the Ni contacts on the Bi 2 Te 3 based legs. Thus Co could be a suitable diffusion barrier for bulk Bi 2 Te 3 based material. The observed effects on the thermoelectric and structural properties of metal/Bi 2 Te 3 based material are crucial for understanding the interface between the diffusion barrier and thermoelectric materials. - Highlights: • Interface characterization of metal coated to p-type and n-type Bi 2 Te 3 is studied. • We examined the phase transformation of metal/Bi 2 Te 3 based films

Thermodynamics of post-growth annealing of cadmium zinc telluride nuclear radiation detectors

Science.gov (United States)

Adams, Aaron Lee

Nuclear Radiation Detectors are used for detecting, tracking, and identifying radioactive materials which emit high-energy gamma and X-rays. The use of Cadmium Zinc Telluride (CdZnTe) detectors is particularly attractive because of the detector's ability to operate at room temperature and measure the energy spectra of gamma-ray sources with a high resolution, typically less than 1% at 662 keV. While CdZnTe detectors are acceptable imperfections in the crystals limit their full market potential. One of the major imperfections are Tellurium inclusions generated during the crystal growth process by the retrograde solubility of Tellurium and Tellurium-rich melt trapped at the growth interface. Tellurium inclusions trap charge carriers generated by gamma and X-ray photons and thus reduce the portion of generated charge carriers that reach the electrodes for collection and conversion into a readable signal which is representative of the ionizing radiation's energy and intensity. One approach in resolving this problem is post-growth annealing which has the potential of removing the Tellurium inclusions and associated impurities. The goal of this project is to use experimental techniques to study the thermodynamics of Tellurium inclusion migration in post-growth annealing of CdZnTe nuclear detectors with the temperature gradient zone migration (TGZM) technique. Systematic experiments will be carried out to provide adequate thermodynamic data that will inform the engineering community of the optimum annealing parameters. Additionally, multivariable correlations that involve the Tellurium diffusion coefficient, annealing parameters, and CdZnTe properties will be analyzed. The experimental approach will involve systematic annealing experiments (in Cd vapor overpressure) on different sizes of CdZnTe crystals at varying temperature gradients ranging from 0 to 60°C/mm (used to migrate the Tellurium inclusion to one side of the crystal), and at annealing temperatures ranging

Derived reference doses for three compounds used in the photovoltaics industry: Copper indium diselenide, copper gallium diselenide, and cadmium telluride

Energy Technology Data Exchange (ETDEWEB)

Moskowitz, P.D.; Bernholc, N.; DePhillips, M.P.; Viren, J.

1995-07-06

Polycrystalline thin-film photovoltaic modules made from copper indium diselenide (CIS), copper gallium diselenide (CGS), and cadmium telluride (CdTe) arc nearing commercial development. A wide range of issues are being examined as these materials move from the laboratory to large-scale production facilities to ensure their commercial success. Issues of traditional interest include module efficiency, stability and cost. More recently, there is increased focus given to environmental, health and safety issues surrounding the commercialization of these same devices. An examination of the toxicological properties of these materials, and their chemical parents is fundamental to this discussion. Chemicals that can present large hazards to human health or the environment are regulated often more strictly than those that are less hazardous. Stricter control over how these materials are handled and disposed can increase the costs associated with the production and use of these modules dramatically. Similarly, public perception can be strongly influenced by the inherent biological hazard that these materials possess. Thus, this report: presents a brief background tutorial on how toxicological data are developed and used; overviews the toxicological data available for CIS, CGS and CdTe; develops ``reference doses`` for each of these compounds; compares the reference doses for these compounds with those of their parents; discusses the implications of these findings to photovoltaics industry.

Modelling of illuminated current–voltage characteristics to evaluate leakage currents in long wavelength infrared mercury cadmium telluride photovoltaic detectors

International Nuclear Information System (INIS)

Gopal, Vishnu; Qiu, WeiCheng; Hu, Weida

2014-01-01

The current–voltage characteristics of long wavelength mercury cadmium telluride infrared detectors have been studied using a recently suggested method for modelling of illuminated photovoltaic detectors. Diodes fabricated on in-house grown arsenic and vacancy doped epitaxial layers were evaluated for their leakage currents. The thermal diffusion, generation–recombination (g-r), and ohmic currents were found as principal components of diode current besides a component of photocurrent due to illumination. In addition, both types of diodes exhibited an excess current component whose growth with the applied bias voltage did not match the expected growth of trap-assisted-tunnelling current. Instead, it was found to be the best described by an exponential function of the type, I excess  = I r0  + K 1 exp (K 2 V), where I r0 , K 1 , and K 2 are fitting parameters and V is the applied bias voltage. A study of the temperature dependence of the diode current components and the excess current provided the useful clues about the source of origin of excess current. It was found that the excess current in diodes fabricated on arsenic doped epitaxial layers has its origin in the source of ohmic shunt currents. Whereas, the source of excess current in diodes fabricated on vacancy doped epitaxial layers appeared to be the avalanche multiplication of photocurrent. The difference in the behaviour of two types of diodes has been attributed to the difference in the quality of epitaxial layers

Inhibition of autophagy contributes to the toxicity of cadmium telluride quantum dots in Saccharomyces cerevisiae

Directory of Open Access Journals (Sweden)

Fan J

2016-07-01

Full Text Available Junpeng Fan,1–4 Ming Shao,1–4 Lu Lai,3–5 Yi Liu,3–5 Zhixiong Xie1–4,6 1College of Life Sciences, Wuhan University, 2Hubei Provincial Cooperative Innovation Center of Industrial Fermentation,3State Key Laboratory of Virology, 4Key Laboratory of Analytical Chemistry for Biology and Medicine (MOE, 5College of Chemistry and Molecular Sciences, Wuhan University, Wuhan, 6School of Life Science and Technology, Hubei Engineering University, Xiaogan, People’s Republic of China Abstract: Cadmium telluride quantum dots (CdTe QDs are used as near-infrared probes in biologic and medical applications, but their cytological effects and mechanism of potential toxicity are still unclear. In this study, we evaluated the toxicity of CdTe QDs of different sizes and investigated their mechanism of toxicity in the yeast Saccharomyces cerevisiae. A growth inhibition assay revealed that orange-emitting CdTe (O-CdTe QDs (half inhibitory concentration [IC50] =59.44±12.02 nmol/L were more toxic than green-emitting CdTe QDs (IC50 =186.61±19.74 nmol/L to S. cerevisiae. Further studies on toxicity mechanisms using a transmission electron microscope and green fluorescent protein tagged Atg8 processing assay revealed that O-CdTe QDs could partially inhibit autophagy at a late stage, which differs from the results reported in mammalian cells. Moreover, autophagy inhibited at a late stage by O-CdTe QDs could be partially recovered by enhancing autophagy with rapamycin (an autophagy activator, combined with an increased number of living cells. These results indicate that inhibition of autophagy acts as a toxicity mechanism of CdTe QDs in S. cerevisiae. This work reports a novel toxicity mechanism of CdTe QDs in yeast and provides valuable information on the effect of CdTe QDs on the processes of living cells. Keywords: CdTe quantum dots, Saccharomyces cerevisiae, toxicity, autophagy

Cadmium Manganese Telluride (Cd1-xMnxTe): A potential material for room-temperature radiation detectors

Energy Technology Data Exchange (ETDEWEB)

Hossain, A.; Cui, Y.; Bolotnikov, A.; Camarda, G.; Yang, G.; Kim, K-H.; Gul, R.; Xu, L.; Li, L.; Mycielski, A.; and James, R.B.

2010-07-11

Cadmium Manganese Telluride (CdMnTe) recently emerged as a promising material for room-temperature X- and gamma-ray detectors. It offers several potential advantages over CdZnTe. Among them is its optimal tunable band gap ranging from 1.7-2.2 eV, and its relatively low (< 50%) content of Mn compared to that of Zn in CdZnTe that assures this favorable band-gap range. Another important asset is the segregation coefficient of Mn in CdTe that is approximately unity compared to 1.35 for Zn in CdZnTe, so ensuring the homogenous distribution of Mn throughout the ingot; hence, a large-volume stoichiometric yield is attained. However, some materials issues primarily related to the growth process impede the production of large, defect-free single crystals. The high bond-ionicity of CdMnTe entails a higher propensity to crystallize into a hexagonal structure rather than to adopt the expected zinc-blend structure, which is likely to generate twins in the crystals. In addition, bulk defects generate in the as-grown crystals due to the dearth of high-purity Mn, which yields a low-resistivity material. In this presentation, we report on our observations of such material defects in current CdMnTe materials, and our evaluation of its potential as an alternative detector material to the well-known CdZnTe detectors. We characterized the bulk defects of several indium- and vanadium-doped Cd1-xMnxTe crystals by using several advanced techniques, viz., micro-scale mapping, white-beam x-ray diffraction/reflection topography, and chemical etching. Thereafter, we fabricated some detectors from selected CdMnTe crystals, characterized their electrical properties, and tested their performance as room-temperature X- and gamma-ray detectors. Our experimental results indicate that CdMnTe materials could well prove to become a viable alternative in the near future.

Enhancing Thermoelectric Performances of Bismuth Antimony Telluride via Synergistic Combination of Multiscale Structuring and Band Alignment by FeTe2 Incorporation.

Science.gov (United States)

Shin, Weon Ho; Roh, Jong Wook; Ryu, Byungki; Chang, Hye Jung; Kim, Hyun Sik; Lee, Soonil; Seo, Won Seon; Ahn, Kyunghan

2018-01-31

It has been a difficulty to form well-distributed nano- and mesosized inclusions in a Bi 2 Te 3 -based matrix and thereby realizing no degradation of carrier mobility at interfaces between matrix and inclusions for high thermoelectric performances. Herein, we successfully synthesize multistructured thermoelectric Bi 0.4 Sb 1.6 Te 3 materials with Fe-rich nanoprecipitates and sub-micron FeTe 2 inclusions by a conventional solid-state reaction followed by melt-spinning and spark plasma sintering that could be a facile preparation method for scale-up production. This study presents a bismuth antimony telluride based thermoelectric material with a multiscale structure whose lattice thermal conductivity is drastically reduced with minimal degradation on its carrier mobility. This is possible because a carefully chosen FeTe 2 incorporated in the matrix allows its interfacial valence band with the matrix to be aligned, leading to a significantly improved p-type thermoelectric power factor. Consequently, an impressively high thermoelectric figure of merit ZT of 1.52 is achieved at 396 K for p-type Bi 0.4 Sb 1.6 Te 3 -8 mol % FeTe 2 , which is a 43% enhancement in ZT compared to the pristine Bi 0.4 Sb 1.6 Te 3 . This work demonstrates not only the effectiveness of multiscale structuring for lowering lattice thermal conductivities, but also the importance of interfacial band alignment between matrix and inclusions for maintaining high carrier mobilities when designing high-performance thermoelectric materials.

Comparison between stress myocardial perfusion SPECT recorded with cadmium-zinc-telluride and Anger cameras in various study protocols

International Nuclear Information System (INIS)

Verger, Antoine; Karcher, Gilles; Djaballah, Wassila; Fourquet, Nicolas; Rouzet, Francois; Le Guludec, Dominique; Koehl, Gregoire; Roch, Veronique; Imbert, Laetitia; Poussier, Sylvain; Fay, Renaud; Marie, Pierre-Yves

2013-01-01

The results of stress myocardial perfusion SPECT could be enhanced by new cadmium-zinc-telluride (CZT) cameras, although differences compared to the results with conventional Anger cameras remain poorly known for most study protocols. This study was aimed at comparing the results of CZT and Anger SPECT according to various study protocols while taking into account the influence of obesity. The study population, which was from three different institutions equipped with identical CZT cameras, comprised 276 patients referred for study using protocols involving 201 Tl (n = 120) or 99m Tc-sestamibi injected at low dose at stress ( 99m Tc-Low; stress/rest 1-day protocol; n = 110) or at high dose at stress ( 99m Tc-High; rest/stress 1-day or 2-day protocol; n = 46). Each Anger SPECT scan was followed by a high-speed CZT SPECT scan (2 to 4 min). Agreement rates between CZT and Anger SPECT were good irrespective of the study protocol (for abnormal SPECT, 201 Tl 92 %, 99m Tc-Low 86 %, 99m Tc-High 98 %), although quality scores were much higher for CZT SPECT with all study protocols. Overall correlations were high for the extent of myocardial infarction (r = 0.80) and a little lower for ischaemic areas (r = 0.72), the latter being larger on Anger SPECT (p 201 Tl or 99m Tc-Low group and in whom stress myocardial counts were particularly low with Anger SPECT (228 ± 101 kcounts) and dramatically enhanced with CZT SPECT (+279 ± 251 %). Concordance between the results of CZT and Anger SPECT is good regardless of study protocol and especially when excluding obese patients who have low-count Anger SPECT and for whom myocardial counts are dramatically enhanced on CZT SPECT. (orig.)

Mechanical properties of bismuth telluride (Bi{sub 2}Te{sub 3}) processed by high pressure torsion (HPT); Propiedades mecanicas del telururo de bismuto (Bi{sub 2}Te{sub 3}) procesado mediante torsion bajo alta presion (HPT)

Energy Technology Data Exchange (ETDEWEB)

Santamaria, J. A.; Alkorta, J.; Gil Sevillano, J.

2013-06-01

Bismuth telluride, Bi{sub 2}Te{sub 3}, is the main thermoelectric material currently in use for commercial cooling devices or for energy harvesting near room temperature. Because of its highly anisotropic layered structure, Bi{sub 2}Te{sub 3} is very brittle, failing by cleavage along its basal plane. Refining its grain size is expected to increase its toughness with the advantage that, simultaneously, its thermoelectric figure of merit results increased. In this work, powders of the compound have been compacted by conventional methods as well as by severe plastic deformation under high pressure (3 GPa) using high pressure torsion (HPT, one turn at room temperature). Near-theoretical density has been achieved. The hardness and toughness of the compacts have been assessed by micro and nano-indentation. (Author) 11 refs.

Interactions between N-acetyl-L-cysteine protected CdTe quantum dots and doxorubicin through spectroscopic method

Energy Technology Data Exchange (ETDEWEB)

Yang, Xiupei, E-mail: xiupeiyang@163.com [Chemical Synthesis and Pollution Control Key Laboratory of Sichuan Province, Nanchong 637000 (China); College of Chemistry and Chemical Engineering, China West Normal University, Nanchong 637000 (China); Lin, Jia; Liao, Xiulin; Zong, Yingying; Gao, Huanhuan [College of Chemistry and Chemical Engineering, China West Normal University, Nanchong 637000 (China)

2015-06-15

Highlights: • CdTe quantum dots with the diameter of 3–5 nm were synthesized in aqueous solution. • The modified CdTe quantum dots showed well fluorescence properties. • The interaction between the CdTe quantum dots and doxorubicin (DR) was investigated. - Abstract: N-acetyl-L-cysteine protected cadmium telluride quantum dots with a diameter of 3–5 nm were synthesized in aqueous solution. The interaction between N-acetyl-L-cysteine/cadmium telluride quantum dots and doxorubicin was investigated by ultraviolet–visible absorption and fluorescence spectroscopy at physiological conditions (pH 7.2, 37 °C). The results indicate that electron transfer has occurred between N-acetyl-L-cysteine/cadmium telluride quantum dots and doxorubicin under light illumination. The quantum dots react readily with doxorubicin to form a N-acetyl-L-cysteine/cadmium telluride-quantum dots/doxorubicin complex via electrostatic attraction between the −NH{sub 3}{sup +} moiety of doxorubicin and the −COO{sup −} moiety of N-acetyl-L-cysteine/cadmium telluride quantum dots. The interaction of N-acetyl-L-cysteine/cadmium telluride-quantum dots/doxorubicin complex with bovine serum albumin was studied as well, showing that the complex might induce the conformation change of bovine serum due to changes in microenvironment of bovine serum.

Interactions between N-acetyl-L-cysteine protected CdTe quantum dots and doxorubicin through spectroscopic method

International Nuclear Information System (INIS)

Yang, Xiupei; Lin, Jia; Liao, Xiulin; Zong, Yingying; Gao, Huanhuan

2015-01-01

Highlights: • CdTe quantum dots with the diameter of 3–5 nm were synthesized in aqueous solution. • The modified CdTe quantum dots showed well fluorescence properties. • The interaction between the CdTe quantum dots and doxorubicin (DR) was investigated. - Abstract: N-acetyl-L-cysteine protected cadmium telluride quantum dots with a diameter of 3–5 nm were synthesized in aqueous solution. The interaction between N-acetyl-L-cysteine/cadmium telluride quantum dots and doxorubicin was investigated by ultraviolet–visible absorption and fluorescence spectroscopy at physiological conditions (pH 7.2, 37 °C). The results indicate that electron transfer has occurred between N-acetyl-L-cysteine/cadmium telluride quantum dots and doxorubicin under light illumination. The quantum dots react readily with doxorubicin to form a N-acetyl-L-cysteine/cadmium telluride-quantum dots/doxorubicin complex via electrostatic attraction between the −NH 3 + moiety of doxorubicin and the −COO − moiety of N-acetyl-L-cysteine/cadmium telluride quantum dots. The interaction of N-acetyl-L-cysteine/cadmium telluride-quantum dots/doxorubicin complex with bovine serum albumin was studied as well, showing that the complex might induce the conformation change of bovine serum due to changes in microenvironment of bovine serum

Definitive Brachytherapy for Kaposi's Sarcoma

International Nuclear Information System (INIS)

Williams, A.; Ezzell, G.; Zalupski, M.; Fontanesi, J.

1996-01-01

Purpose: To assess the efficacy and possible complications in patients diagnosed with Kaposi's sarcoma and treated with definitive brachytherapy. Methods and Materials: Between January, 1995 and December, 1995, four patients with Kaposi's sarcoma (KS) were treated with brachytherapy. Three patients, all with positive HIV status were treated using Iridium 192 (Ir-192) sources via a high-dose rate remote afterloader. One patient with endemic KS was treated using the application of catheters loaded with Californium 252. Eight sites were treated and included scalp, feet, nose, penis, hand, neck, and back. Dose rate for Ir-192 was 330cGy/fx to a total dose of 990cGy. The Californium was delivered as 100nGy/b.i.d. to a total dose of 900nGy. Follow-up as ranged from 2-6 months. Results: All four patients remain alive. Seven of eight sites have had complete clinical response and each patient has reported durable pain relief that has not subsided through last follow-up of 1/96. Two of eight sites, both treated with surface mold technique with Californium 252 developed moist desquamation. The remaining six sites did not demonstrate significant toxicity. Conclusion: Brachytherapy can offer Kaposi's sarcoma patients results that are equivalent to external beam radiation therapy, with minimal complications, a shorter treatment time and potential cost effectiveness

Comparison between stress myocardial perfusion SPECT recorded with cadmium-zinc-telluride and Anger cameras in various study protocols

Energy Technology Data Exchange (ETDEWEB)

Verger, Antoine; Karcher, Gilles [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); INSERM U947, Nancy (France); Nancyclotep Experimental Imaging Platform, Nancy (France); Djaballah, Wassila [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); INSERM U947, Nancy (France); Fourquet, Nicolas [Clinique Pasteur, Toulouse (France); Rouzet, Francois; Le Guludec, Dominique [AP-HP, Hopital Bichat, Department of Nuclear Medicine, Paris (France); INSERM U 773 Inserm and Denis Diderot University, Paris (France); Koehl, Gregoire; Roch, Veronique [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); Nancyclotep Experimental Imaging Platform, Nancy (France); Imbert, Laetitia [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); Nancyclotep Experimental Imaging Platform, Nancy (France); Centre Alexis Vautrin, Department of Radiotherapy, Vandoeuvre (France); Poussier, Sylvain [INSERM U947, Nancy (France); Nancyclotep Experimental Imaging Platform, Nancy (France); Fay, Renaud [INSERM, Centre d' Investigation Clinique CIC-P 9501, Nancy (France); Marie, Pierre-Yves [CHU-Nancy, Department of Nuclear Medicine, Nancy (France); Nancyclotep Experimental Imaging Platform, Nancy (France); INSERM U961, Nancy (France); Hopital de Brabois, CHU-Nancy, Medecine Nucleaire, Vandoeuvre-les-Nancy (France)

2013-03-15

The results of stress myocardial perfusion SPECT could be enhanced by new cadmium-zinc-telluride (CZT) cameras, although differences compared to the results with conventional Anger cameras remain poorly known for most study protocols. This study was aimed at comparing the results of CZT and Anger SPECT according to various study protocols while taking into account the influence of obesity. The study population, which was from three different institutions equipped with identical CZT cameras, comprised 276 patients referred for study using protocols involving {sup 201}Tl (n = 120) or {sup 99m}Tc-sestamibi injected at low dose at stress ({sup 99m}Tc-Low; stress/rest 1-day protocol; n = 110) or at high dose at stress ({sup 99m}Tc-High; rest/stress 1-day or 2-day protocol; n = 46). Each Anger SPECT scan was followed by a high-speed CZT SPECT scan (2 to 4 min). Agreement rates between CZT and Anger SPECT were good irrespective of the study protocol (for abnormal SPECT, {sup 201}Tl 92 %, {sup 99m}Tc-Low 86 %, {sup 99m}Tc-High 98 %), although quality scores were much higher for CZT SPECT with all study protocols. Overall correlations were high for the extent of myocardial infarction (r = 0.80) and a little lower for ischaemic areas (r = 0.72), the latter being larger on Anger SPECT (p < 0.001). This larger extent was mainly observed in 50 obese patients who were in the {sup 201}Tl or {sup 99m}Tc-Low group and in whom stress myocardial counts were particularly low with Anger SPECT (228 {+-} 101 kcounts) and dramatically enhanced with CZT SPECT (+279 {+-} 251 %). Concordance between the results of CZT and Anger SPECT is good regardless of study protocol and especially when excluding obese patients who have low-count Anger SPECT and for whom myocardial counts are dramatically enhanced on CZT SPECT. (orig.)

Diagnostic Performance of a Cadmium-Zinc-Telluride Single-Photon Emission Computed Tomography System With Low-Dose Technetium-99m as Assessed by Fractional Flow Reserve.

Science.gov (United States)

Chikamori, Taishiro; Hida, Satoshi; Tanaka, Nobuhiro; Igarashi, Yuko; Yamashita, Jun; Shiba, Chie; Murata, Naotaka; Hoshino, Kou; Hokama, Yohei; Yamashina, Akira

2016-04-25

Although stress single-photon emission computed tomography (SPECT) using a cadmium-zinc-telluride (CZT) camera facilitates radiation dose reduction, only a few studies have evaluated its diagnostic accuracy in Japanese patients by applying fractional flow reserve (FFR) measurements. We prospectively evaluated 102 consecutive patients with suspected or known coronary artery disease with a low-dose stress/rest protocol ((99m)Tc radiotracer 185/370 MBq) using CZT SPECT. Within 3 months, coronary angiography was performed and a significant stenosis was defined as ≥90% diameter narrowing on visual estimation, or as a lesion of <90% and ≥ 50% stenosis with FFR ≤0.80. To detect individual coronary stenosis, the respective sensitivity, specificity, and accuracy were 86%, 75%, and 82% for left anterior descending artery stenosis, 76%, 81%, and 79% for left circumflex artery stenosis, and 87%, 92%, and 90% for right coronary artery stenosis. When limited to 92 intermediate stenotic lesions in which FFR was measured, stress SPECT showed 77% sensitivity, 91% specificity, and 84% accuracy, whereas the diagnostic value decreased to 52% sensitivity, 68% specificity, and 58% accuracy based only on visual estimation of ≥75% diameter narrowing. CZT SPECT demonstrated a good diagnostic yield in detecting hemodynamically significant coronary stenoses as assessed by FFR, even when using a low-dose (99m)Tc protocol with an effective dose ≤5 mSv. (Circ J 2016; 80: 1217-1224).

Hydrotelluration of alkynes: a unique route to Z-vinyl organometallics

Directory of Open Access Journals (Sweden)

Vieira Maurício L.

2001-01-01

Full Text Available The hydrotelluration reaction of alkynes is reviewed. The transformation of vinylic tellurides into reactive vinyl organometallics and the coupling reactions of vinylic tellurides with alkynes and organometallics are presented.

Studies on focal alveolar bone healing with technetium (Tc)-99m labeled methylene diphosphonate and gold-collimated cadmium telluride probe

International Nuclear Information System (INIS)

Tsuchimochi, M.; Hosain, F.; Engelke, W.; Zeichner, S.J.; Ruttimann, U.E.; Webber, R.L.

1991-01-01

The benefit of using a collimator for a miniaturized cadmium telluride probe was evaluated by monitoring the bone-healing processes for 13 weeks after the induction of small iatrogenic alveolar bone lesions in one side of the mandible in beagles. Technetium (Tc)-99m labeled methylene diphosphonate (200 to 300 MBq, 5.1 to 8.1 mCi, in a solution of 0.5 to 1 ml, intravenously) was used as a bone-seeking radiopharmaceutical. The radioactivity over the bone lesion (L) and the contralateral normal site (C) in the mandible were measured between 1.5 and 2 hours after injection of the tracer, and the activity ratio L/C served as an index of relative bone uptake. A study of six dogs revealed that the healing response to a hemispheric bone defect of 2 mm diameter in the cortical bone could not be detected by an uncollimated probe, and in a repeated study in two dogs the use of a gold collimator (5 mm in diameter, 5 mm in length) did not increase the L/C ratio significantly. A second study in six dogs with 5 mm lesions showed that although systematic trends in the time courses of the L/C ratio obtained both with and without the collimator could be demonstrated, the L/C ratio of collimated versus uncollimated measurements was significantly (p less than 0.005) increased. In three of the latter six dogs, abscesses developed after 9 weeks, leading to a second increase (p less than 0.05) of the L/C ratio with collimation compared with the noninflammation group; without collimation no significant (p greater than 0.15) difference between the two groups could be demonstrated

Californium Recovery from Palladium Wire

Energy Technology Data Exchange (ETDEWEB)

Burns, Jon D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2014-08-01

The recovery of ²⁵²Cf from palladium-²⁵²Cf cermet wires was investigated to determine the feasibility of implementing it into the cermet wire production operation at Oak Ridge National Laboratory’s Radiochemical Engineering Development Center. The dissolution of Pd wire in 8 M HNO₃ and trace amounts of HCl was studied at both ambient and elevated temperatures. These studies showed that it took days to dissolve the wire at ambient temperature and only 2 hours at 60°C. Adjusting the ratio of the volume of solvent to the mass of the wire segment showed little change in the kinetics of dissolution, which ranged from 0.176 mL/mg down to 0.019 mL/mg. A successful chromatographic separation of ¹⁵³Gd, a surrogate for ²⁵²Cf, from Pd was demonstrated using AG 50x8 cation exchange resin with a bed volume of 0.5 mL and an internal diameter of 0.8 cm.

Californium-252 Program Equipment Evaluation

Energy Technology Data Exchange (ETDEWEB)

Chattin, Fred Rhea [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wilson, Kenton [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ezold, Julie G. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

2017-12-01

To successfully continue the ²⁵²Cf production and meet the needs of the customers, a comprehensive evaluation of the Building 7920 processing equipment was requested to identify equipment critical to the operational continuity of the program.

Growth and Characterization of (211)B Cadmium Telluride Buffer Layer Grown by Metal-organic Vapor Phase Epitaxy on Nanopatterned Silicon for Mercury Cadmium Telluride Based Infrared Detector Applications

Science.gov (United States)

Shintri, Shashidhar S.

Mercury cadmium telluride (MCT or Hg1-xCdxTe) grown by molecular beam epitaxy (MBE) is presently the material of choice for fabricating infrared (IR) detectors used in night vision based military applications. The focus of MCT epitaxy has gradually shifted since the last decade to using Si as the starting substrate since it offers several advantages. But the ˜19 % lattice mismatch between MCT and Si generates lots of crystal defects some of which degrade the performance of MCT devices. Hence thick CdTe films are used as buffer layers on Si to accommodate the defects. However, growth of high quality single crystal CdTe on Si is challenging and to date, the best MBE CdTe/Si reportedly has defects in the mid-105 cm -2 range. There is a critical need to reduce the defect levels by at least another order of magnitude, which is the main motivation behind the present work. The use of alternate growth technique called metal-organic vapor phase epitaxy (MOVPE) offers some advantages over MBE and in this work MOVPE has been employed to grow the various epitaxial films. In the first part of this work, conditions for obtaining high quality (211)B CdTe epitaxy on (211)Si were achieved, which also involved studying the effect of having additional intermediate buffer layers such as Ge and ZnTe and incorporation of in-situ thermal cyclic annealing (TCA) to reduce the dislocation density. A critical problem of Si cross-contamination due to 'memory effect' of different reactant species was minimized by introducing tertiarybutylArsine (TBAs) which resulted in As-passivation of (211)Si. The best 8-10 µm thick CdTe films on blanket (non-patterned) Si had dislocations around 3×105 cm-2, which are the best reported by MOVPE till date and comparable to the highest quality films available by MBE. In the second part of the work, nanopatterned (211)Si was used to study the effect of patterning on the crystal quality of epitaxial CdTe. In one such study, patterning of ˜20 nm holes in SiO2

Transport properties of silver telluride in the solid and liquid states; Etude des proprietes de transport dans le tellurure d'argent Ag{sub 2}Te aux hautes temperatures a l'etat solide et a l'etat liquide

Energy Technology Data Exchange (ETDEWEB)

Pham, N T [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1969-01-01

Measurements of the electrical resistivity, Hall coefficient and thermoelectric power have been carried out for silver telluride over a large temperature range including both solid and liquid states. The analysis of the experimental data shows that in the solid state the transport properties are governed by an ambipolar process with an electron mobility much higher than the hole mobility ({mu}{sub n} = 10*{mu}{sub p}). It is found that the temperature dependence of the electron mobility can be represented by a T{sup -3} law. Deviations from the stoichiometric composition Ag{sub 2}Te have been studied. For all specimens, melting is accompanied by discontinuous variations in the transport properties. Above the melting point, the magnitude of the measured parameters and their temperature dependence show that liquid silver telluride behaves as a semiconductor. The contribution of Ag{sup +} ions to transport phenomena is suggested to account for the behaviour of the electrical properties. Experimental data have been analysed in terms of conventional theories. (author) [French] Les mesures de la resistivite electrique, du coefficient de Hall et du pouvoir thermoelectrique ont ete effectuees sur le tellurure d'argent dans un large domaine de temperature couvrant l'etat solide et l'etat liquide. L'analyse des resultats experimentaux obtenus a l'etat solide montre que les proprietes de transport sont gouvernees par le processus ambipolaire avec une mobilite des electrons beaucoup plus grande que celle des trous ({mu}{sub n} 10*{mu}{sub p}). On trouve que la mobilite des electrons varie avec la temperature suivant la loi T{sup -3}. Les ecarts de la composition stoechiometrique Ag{sub 2}Te ont ete etudies. Pour tous les echantillons, la fusion est caracterisee par des variations discontinues des proprietes de transport. Au dessus du point de fusion, la grandeur des parametres mesures ainsi que leur variation avec la temperature montrent que le tellurure d'argent liquide se

Design study of a high-resolution breast-dedicated PET system built from cadmium zinc telluride detectors

International Nuclear Information System (INIS)

Peng Hao; Levin, Craig S

2010-01-01

We studied the performance of a dual-panel positron emission tomography (PET) camera dedicated to breast cancer imaging using Monte Carlo simulation. The proposed system consists of two 4 cm thick 12 x 15 cm 2 area cadmium zinc telluride (CZT) panels with adjustable separation, which can be put in close proximity to the breast and/or axillary nodes. Unique characteristics distinguishing the proposed system from previous efforts in breast-dedicated PET instrumentation are the deployment of CZT detectors with superior spatial and energy resolution, using a cross-strip electrode readout scheme to enable 3D positioning of individual photon interaction coordinates in the CZT, which includes directly measured photon depth-of-interaction (DOI), and arranging the detector slabs edge-on with respect to incoming 511 keV photons for high photon sensitivity. The simulation results show that the proposed CZT dual-panel PET system is able to achieve superior performance in terms of photon sensitivity, noise equivalent count rate, spatial resolution and lesion visualization. The proposed system is expected to achieve ∼32% photon sensitivity for a point source at the center and a 4 cm panel separation. For a simplified breast phantom adjacent to heart and torso compartments, the peak noise equivalent count (NEC) rate is predicted to be ∼94.2 kcts s -1 (breast volume: 720 cm 3 and activity concentration: 3.7 kBq cm -3 ) for a ∼10% energy window around 511 keV and ∼8 ns coincidence time window. The system achieves 1 mm intrinsic spatial resolution anywhere between the two panels with a 4 cm panel separation if the detectors have DOI resolution less than 2 mm. For a 3 mm DOI resolution, the system exhibits excellent sphere resolution uniformity (σ rms /mean) ≤ 10%) across a 4 cm width FOV. Simulation results indicate that the system exhibits superior hot sphere visualization and is expected to visualize 2 mm diameter spheres with a 5:1 activity concentration ratio within

Sc, Y, La-Lu - Rare Earth Elements

International Nuclear Information System (INIS)

Anon.

1987-01-01

At present extensive efforts are being made in completing work on system number Rare Earth Elements. Part A is devoted to the occurrence of these elements on the earth and in the universe. Part B deals with the pure metals; the 7 volumes published cover the description of the separation from the raw materials, the preparation of pure metals,their uses and toxicology, the physical properties of nuclei, atoms, molecules, and isotopes; in addition the behavior of ions in solution and the electrochemical behavior of rare earth elements are described. The compounds are described in Part C. Part D with 6 volumes has been devoted to the description of coordination compounds and is completed. The volume ''Rare Earth Elements C 10'' deals with the rare earth tellurides, oxide tellurides, tellurates, telluride halides, tellurate halides, sulfide tellurides, selenide tellurides, and alkali rare earth tellurates. Another topic of this volume are the compounds of the rare earth elements with polonium. So far as meaningful and in accordance with all earlier volumes of ''Rare Earth Elements'' Series C, comparative data are presented in sections preceding treatment of the individual compounds and systems

Demonstration of iodine K-edge imaging by use of an energy-discrimination X-ray computed tomography system with a cadmium telluride detector.

Science.gov (United States)

Abudurexiti, Abulajiang; Kameda, Masashi; Sato, Eiichi; Abderyim, Purkhet; Enomoto, Toshiyuki; Watanabe, Manabu; Hitomi, Keitaro; Tanaka, Etsuro; Mori, Hidezo; Kawai, Toshiaki; Takahashi, Kiyomi; Sato, Shigehiro; Ogawa, Akira; Onagawa, Jun

2010-07-01

An energy-discrimination K-edge X-ray computed tomography (CT) system is useful for increasing the contrast resolution of a target region by utilizing contrast media. The CT system has a cadmium telluride (CdTe) detector, and a projection curve is obtained by linear scanning with use of the CdTe detector in conjunction with an X-stage. An object is rotated by a rotation step angle with use of a turntable between the linear scans. Thus, CT is carried out by repetition of the linear scanning and the rotation of an object. Penetrating X-ray photons from the object are detected by the CdTe detector, and event signals of X-ray photons are produced with use of charge-sensitive and shaping amplifiers. Both the photon energy and the energy width are selected by use of a multi-channel analyzer, and the number of photons is counted by a counter card. For performing energy discrimination, a low-dose-rate X-ray generator for photon counting was developed; the maximum tube voltage and the minimum tube current were 110 kV and 1.0 microA, respectively. In energy-discrimination CT, the tube voltage and the current were 60 kV and 20.0 microA, respectively, and the X-ray intensity was 0.735 microGy/s at 1.0 m from the source and with a tube voltage of 60 kV. Demonstration of enhanced iodine K-edge X-ray CT was carried out by selection of photons with energies just beyond the iodine K-edge energy of 33.2 keV.

Performance of cardiac cadmium-zinc-telluride gamma camera imaging in coronary artery disease: a review from the cardiovascular committee of the European Association of Nuclear Medicine (EANM)

International Nuclear Information System (INIS)

Agostini, Denis; Marie, Pierre-Yves; Ben-Haim, Simona; Rouzet, Francois; Songy, Bernard; Giordano, Alessandro; Gimelli, Alessia; Hyafil, Fabien; Sciagra, Roberto; Bucerius, Jan; Verberne, Hein J.; Slart, Riemer H.J.A.; Lindner, Oliver

2016-01-01

The trade-off between resolution and count sensitivity dominates the performance of standard gamma cameras and dictates the need for relatively high doses of radioactivity of the used radiopharmaceuticals in order to limit image acquisition duration. The introduction of cadmium-zinc-telluride (CZT)-based cameras may overcome some of the limitations against conventional gamma cameras. CZT cameras used for the evaluation of myocardial perfusion have been shown to have a higher count sensitivity compared to conventional single photon emission computed tomography (SPECT) techniques. CZT image quality is further improved by the development of a dedicated three-dimensional iterative reconstruction algorithm, based on maximum likelihood expectation maximization (MLEM), which corrects for the loss in spatial resolution due to line response function of the collimator. All these innovations significantly reduce imaging time and result in a lower patient's radiation exposure compared with standard SPECT. To guide current and possible future users of the CZT technique for myocardial perfusion imaging, the Cardiovascular Committee of the European Association of Nuclear Medicine, starting from the experience of its members, has decided to examine the current literature regarding procedures and clinical data on CZT cameras. The committee hereby aims (1) to identify the main acquisitions protocols; (2) to evaluate the diagnostic and prognostic value of CZT derived myocardial perfusion, and finally (3) to determine the impact of CZT on radiation exposure. (orig.)

Performance of cardiac cadmium-zinc-telluride gamma camera imaging in coronary artery disease: a review from the cardiovascular committee of the European Association of Nuclear Medicine (EANM)

Energy Technology Data Exchange (ETDEWEB)

Agostini, Denis [CHU Caen and Normandy University, Department of Nuclear Medicine, Caen (France); Normandy University, Caen (France); Marie, Pierre-Yves [University of Lorraine, Faculty of Medicine, Nancyclotep Experimental Imaging Platform, Nancy (France); University of Lorraine, Faculty of Medicine, CHU Nancy, Department of Nuclear Medicine, Nancy (France); University of Lorraine, Faculty of Medicine, Nancy (France); Ben-Haim, Simona [University College London, University College Hospital, Institute of Nuclear Medicine, London (United Kingdom); Chaim Sheba Medical Center, Department of Nuclear Medicine, Ramat Gan (Israel); Rouzet, Francois [University Hospital of Paris-Bichat, UMR 1148, Inserm et Paris Diderot-Paris 7 University Paris, Department of Nuclear Medicine, Paris (France); UMR 1148, Inserm and Paris Diderot-Paris 7 University Paris, Paris (France); Songy, Bernard [Centre Cardiologique du Nord, Saint-Denis (France); Giordano, Alessandro [Institute of Nuclear Medicine, Catholic University of Sacred Heart, Largo A. Gemelli, Department of Bioimages and Radiological Sciences, Rome (Italy); Gimelli, Alessia [Fondazione Toscana Gabriele Monasterio, Pisa (Italy); Hyafil, Fabien [Bichat University Hospital, Assistance Publique - Hopitaux de Paris, UMR 1148, Inserm and Paris Diderot-Paris 7 University, Department of Nuclear Medicine, Paris (France); Sciagra, Roberto [University of Florence, Nuclear Medicine Unit, Department of Experimental and Clinical Biomedical Sciences, Florence (Italy); Bucerius, Jan [Maastricht University Medical Center, Maastricht University Medical Center, Department of Nuclear Medicine, Maastricht (Netherlands); Maastricht University Medical Center, Cardiovascular Research Institute Maastricht (CARIM), Maastricht (Netherlands); University Hospital RWTH Aachen, Department of Nuclear Medicine, Aachen (Germany); Verberne, Hein J. [Academic Medical Center, Department of Nuclear Medicine, Amsterdam (Netherlands); Slart, Riemer H.J.A. [University Medical Center Groningen, Department of Nuclear Medicine and Molecular Imaging, Groningen (Netherlands); University of Twente, Faculty of Science and Technology, Department of Biomedical Photonic Imaging, Enschede (Netherlands); Lindner, Oliver [Institute of Radiology, Nuclear Medicine and Molecular Imaging, Heart and Diabetes Center NRW, Bad Oeynhausen (Germany); Collaboration: Cardiovascular Committee of the European Association of Nuclear Medicine (EANM)

2016-12-15

The trade-off between resolution and count sensitivity dominates the performance of standard gamma cameras and dictates the need for relatively high doses of radioactivity of the used radiopharmaceuticals in order to limit image acquisition duration. The introduction of cadmium-zinc-telluride (CZT)-based cameras may overcome some of the limitations against conventional gamma cameras. CZT cameras used for the evaluation of myocardial perfusion have been shown to have a higher count sensitivity compared to conventional single photon emission computed tomography (SPECT) techniques. CZT image quality is further improved by the development of a dedicated three-dimensional iterative reconstruction algorithm, based on maximum likelihood expectation maximization (MLEM), which corrects for the loss in spatial resolution due to line response function of the collimator. All these innovations significantly reduce imaging time and result in a lower patient's radiation exposure compared with standard SPECT. To guide current and possible future users of the CZT technique for myocardial perfusion imaging, the Cardiovascular Committee of the European Association of Nuclear Medicine, starting from the experience of its members, has decided to examine the current literature regarding procedures and clinical data on CZT cameras. The committee hereby aims (1) to identify the main acquisitions protocols; (2) to evaluate the diagnostic and prognostic value of CZT derived myocardial perfusion, and finally (3) to determine the impact of CZT on radiation exposure. (orig.)

Rajnikant

Indian Academy of Sciences (India)

Synthesis of copper telluride nanowires using template-based electrodeposition method as chemical sensor · Sandeep Arya Saleem Khan Suresh Kumar Rajnikant Verma Parveen Lehana · More Details Abstract Fulltext PDF. Copper telluride (CuTe) nanowires were synthesized electrochemically from aqueous acidic ...

Scientific/Technical Report: Improvement in compensation and crystal growth of cadmium zinc telluride radiation detectors

International Nuclear Information System (INIS)

Kelvin G. Lynn; Kelly A. Jones

2007-01-01

Comparison of actual accomplishments with goals and objectives: (1) Growth of 12 ingots--Washington State University (WSU) more than met this goal for the project by growing 12 final ingots for the year. Nine of the twelve crystal growth ingots resolved gamma radiation at room temperature. The other three ingots where resistivity of ∼ 3 x 10 8 Ohm*cm for CG32a, CG36, and CG42 lower than expected, however none of these were tried with blocking contacts. All ingots were evaluated from tip to heel. In these three cases, the group III, dopant Aluminum (Al) was not detected to a level to compensate the Cd vacancies in the cadmium zinc telluride (CZT) thus the ingots were lower resistivity. The nine ingots that were successful radiation detectors averaged a bulk resistivity of 1.25 x 10 10 Ohm*cm and with a average μτ product for electrons of ∼ 2 x 10 -4 cm 2 /V with a 1/4 microsecond shaping time with samples ∼2 mm in thickness. (2) Attempt new compensations techniques--WSU also met this goal. Several doping schemes were attempted and investigated with various amounts of excess Tellurium added to the growth. The combination of Al and Erbium (Er) were first attempted for these ingots and subsequently CG34 was grown with Al, Er and Holmium. These compensation techniques produced radiation detectors and are currently under investigation. These growths were made with significant different doping levels to determine the affect of the dopants. CG43 was doped with Indium and Er. Indium was introduced instead of Al to determine if Indium is more soluble than Al for CZT and was less oxidized. This may decrease the amount of low resistivity ingots grown by doping with Indium instead of Al. (3) Grow large single crystals--Several changes in approach occurred in the crystal growth furnace. Steps were taken to maximize the crystal growth interface during growth by modifying liners, quartz, heat sinks, crucibles and various growth steps and temperature profiles. CG39 ingot

NREL Achieves Solar-Electric Record

Science.gov (United States)

Solar-Electric Record New Technology Could Spur Growth in Photovoltaic Panels For more information thin-film panels made from cadmium telluride. Benner said these and other plants may adopt all or part panels. Of the several materials that can be used for thin-film panels, cadmium telluride yields higher

with palladium (ii)

African Journals Online (AJOL)

Mgina

Mercury telluride is an important semi conductor with application in infra-red detection (Charlon 1982, Mullin & Irrine. 1985). Photolysis of mixture of the organometallic compounds RHgTeR and. RCdTeR can produce mercury cadmium telluride. Haris and Nissan (1987) prepared. (t-butyl)HgTe(t-butyl) and demonstrated that.

Comparison of conventional and cadmium-zinc-telluride single-photon emission computed tomography for analysis of thallium-201 myocardial perfusion imaging: an exploratory study in normal databases for different ethnicities.

Science.gov (United States)

Ishihara, Masaru; Onoguchi, Masahisa; Taniguchi, Yasuyo; Shibutani, Takayuki

2017-12-01

The aim of this study was to clarify the differences in thallium-201-chloride (thallium-201) myocardial perfusion imaging (MPI) scans evaluated by conventional anger-type single-photon emission computed tomography (conventional SPECT) versus cadmium-zinc-telluride SPECT (CZT SPECT) imaging in normal databases for different ethnic groups. MPI scans from 81 consecutive Japanese patients were examined using conventional SPECT and CZT SPECT and analyzed with the pre-installed quantitative perfusion SPECT (QPS) software. We compared the summed stress score (SSS), summed rest score (SRS), and summed difference score (SDS) for the two SPECT devices. For a normal MPI reference, we usually use Japanese databases for MPI created by the Japanese Society of Nuclear Medicine, which can be used with conventional SPECT but not with CZT SPECT. In this study, we used new Japanese normal databases constructed in our institution to compare conventional and CZT SPECT. Compared with conventional SPECT, CZT SPECT showed lower SSS (p < 0.001), SRS (p = 0.001), and SDS (p = 0.189) using the pre-installed SPECT database. In contrast, CZT SPECT showed no significant difference from conventional SPECT in QPS analysis using the normal databases from our institution. Myocardial perfusion analyses by CZT SPECT should be evaluated using normal databases based on the ethnic group being evaluated.

Californium Cf-252 for pelvic radiotherapy

Energy Technology Data Exchange (ETDEWEB)

Maruyama, Y; Feola, J M; Tai, D; Wilson, L C; Van Nagell, J R; Yoneda, J

1978-01-01

Clinical data about therapy concerning tumors of the female gynecological cancers of the cervix, vagina and uterus are reviewed. Dosimetric, laboratory and radiobiological research data form the basis for an approach to such tumors using Cf-252 as a form of boost brachytherapy. Extreme personnel hazards are a real and important consideration and indicate that maximal containment and isolation procedures should be exercised in its use.

Carrier Transport, Recombination, and the Effects of Grain Boundaries in Polycrystalline Cadmium Telluride Thin Films for Photovoltaics

Science.gov (United States)

Tuteja, Mohit

Cadmium Telluride (CdTe), a chalcogenide semiconductor, is currently used as the absorber layer in one of the highest efficiency thin film solar cell technologies. Current efficiency records are over 22%. In 2011, CdTe solar cells accounted for 8% of all solar cells installed. This is because, in part, CdTe has a low degradation rate, high optical absorption coefficient, and high tolerance to intrinsic defects. Solar cells based on polycrystalline CdTe exhibit a higher short-circuit current, fill factor, and power conversion efficiency than their single crystal counterparts. This is despite the fact that polycrystalline CdTe devices exhibit lower open-circuit voltages. This is contrary to the observation for silicon and III-V semiconductors, where material defects cause a dramatic drop in device performance. For example, grain boundaries in covalently-bonded semiconductors (a) act as carrier recombination centers, and (b) lead to localized energy states, causing carrier trapping. Despite significant research to date, the mechanism responsible for the superior current collection properties of polycrystalline CdTe solar cells has not been conclusively answered. This dissertation focuses on the macro-scale electronic band structure, and micro scale electronic properties of grains and grain boundaries in device-grade CdTe thin films to answer this open question. My research utilized a variety of experimental techniques. Samples were obtained from leading groups fabricating the material and devices. A CdCl 2 anneal is commonly performed as part of this fabrication and its effects were also investigated. Photoluminescence (PL) spectroscopy was employed to study the band structure and defect states in CdTe polycrystals. Cadmium vacancy- and chlorine-related states lead to carrier recombination, as in CdTe films grown by other methods. Comparing polycrystalline and single crystal CdTe, showed that the key to explaining the improved performance of polycrystalline CdTe does

(99m)Tc-MDP bone scintigraphy of the hand: comparing the use of novel cadmium zinc telluride (CZT) and routine NaI(Tl) detectors.

Science.gov (United States)

Koulikov, Victoria; Lerman, Hedva; Kesler, Mikhail; Even-Sapir, Einat

2015-12-01

Cadmium zinc telluride (CZT) solid-state detectors have been recently introduced in the field of nuclear medicine in cardiology and breast imaging. The aim of the current study was to evaluate the performance of the novel detectors (CZT) compared to that of the routine NaI(Tl) in bone scintigraphy. A dual-headed CZT-based camera dedicated originally to breast imaging has been used, and in view of the limited size of the detectors, the hands were chosen as the organ for assessment. This is a clinical study. Fifty-eight consecutive patients (total 116 hands) referred for bone scan for suspected hand pathology gave their informed consent to have two acquisitions, using the routine camera and the CZT-based camera. The latter was divided into full-dose full-acquisition time (FD CZT) and reduced-dose short-acquisition time (RD CZT) on CZT technology, so three image sets were available for analysis. Data analysis included comparing the detection of hot lesions and identification of the metacarpophalangeal, proximal interphalangeal, and distal interphalangeal joints. A total of 69 hot lesions were detected on the CZT image sets; of these, 61 were identified as focal sites of uptake on NaI(Tl) data. On FD CZT data, 385 joints were identified compared to 168 on NaI(Tl) data (p < 0.001). There was no statistically significant difference in delineation of joints between FD and RD CZT data as the latter identified 383 joints. Bone scintigraphy using a CZT-based gamma camera is associated with improved lesion detection and anatomic definition. The superior physical characteristics of this technique raised a potential reduction in administered dose and/or acquisition time without compromising image quality.

Neutron spectra from radionuclide sources for cardiac pacemakers

International Nuclear Information System (INIS)

Kluge, H.

1975-01-01

Neutron spectra from Plutonium 238 radioisotope batteries powering cardiac pacemakers are measured in the energy range above 0.7 MeV. The results are used to calculate radiation doses within a cylindrical phantom. There are only minor differences between the different types of plutonium 238-batteries and californium 252-batteries

Theoretical and Experimental Study on the Permittivity of CdTe in the Terahertz Band

Directory of Open Access Journals (Sweden)

Sun Wang

2018-02-01

Full Text Available The phonon dispersion spectrum, eigenvector, and lattice vibration frequency of cadmium telluride with a zinc blende structure have been investigated using the density functional theory, and the permittivity of cadmium telluride crystal is numerically calculated. The permittivity of the crystal is measured using the terahertz time-domain spectroscopy system. The experimental results are consistent with the theoretical calculations on the modified local density approximation, the general gradient approximation, and the modified general gradient approximation. Finally, the differences among the three approximate exchange correlation potentials indicate that in the terahertz region, the permittivity of cadmium telluride is dominantly contributed by the coupling between electron and phonon; however, the phonon frequencies of transverse wave and longitudinal wave were sensitive to electron density distribution.

Landfill waste and recycling: Use of a screening-level risk assessment tool for end-of-life cadmium telluride (CdTe) thin-film photovoltaic (PV) panels

International Nuclear Information System (INIS)

Cyrs, William D.; Avens, Heather J.; Capshaw, Zachary A.; Kingsbury, Robert A.; Sahmel, Jennifer; Tvermoes, Brooke E.

2014-01-01

Grid-connected solar photovoltaic (PV) power is currently one of the fastest growing power-generation technologies in the world. While PV technologies provide the environmental benefit of zero emissions during use, the use of heavy metals in thin-film PV cells raises important health and environmental concerns regarding the end-of-life disposal of PV panels. To date, there is no published quantitative assessment of the potential human health risk due to cadmium leaching from cadmium telluride (CdTe) PV panels disposed in a landfill. Thus, we used a screening-level risk assessment tool to estimate possible human health risk associated with disposal of CdTe panels into landfills. In addition, we conducted a literature review of potential cadmium release from the recycling process in order to contrast the potential health risks from PV panel disposal in landfills to those from PV panel recycling. Based on the results of our literature review, a meaningful risk comparison cannot be performed at this time. Based on the human health risk estimates generated for PV panel disposal, our assessment indicated that landfill disposal of CdTe panels does not pose a human health hazard at current production volumes, although our results pointed to the importance of CdTe PV panel end-of-life management. - Highlights: • Analysis of possible human health risk posed by disposal of CdTe panels into landfills. • Qualitative comparison of risks associated with landfill disposal and recycling of CdTe panels. • Landfill disposal of CdTe panels does not pose a human health hazard at current production volumes. • There could be potential risks associated with recycling if not properly managed. • Factors other than concerns over toxic substances will likely drive the decisions of how to manage end-of-life PV panels

Sputtered indium-tin oxide/cadmium telluride junctions and cadmium telluride surfaces

International Nuclear Information System (INIS)

Courreges, F.G.; Fahrenbruch, A.L.; Bube, R.H.

1980-01-01

The properties of indium-tin oxide (ITO)/CdTe junction solar cells prepared by rf sputtering of ITO on P-doped CdTe single-crystal substrates have been investigated through measurements of the electrical and photovoltaic properties of ITO/CdTe and In/CdTe junctions, and of electron beam induced currents (EBIC) in ITO/CdTe junctions. In addition, surface properties of CdTe related to the sputtering process were investigated as a function of sputter etching and thermal oxidation using the techniques of surface photovoltage and photoluminescence. ITO/CdTe cells prepared by this sputtering method consist of an n + -ITO/n-CdTe/p-CdTe buried homojunction with about a 1-μm-thick n-type CdTe layer formed by heating of the surface of the CdTe during sputtering. Solar efficiencies up to 8% have been observed with V/sub 0c/=0.82 V and J/sub s/c=14.5 mA/cm 2 . The chief degradation mechanism involves a decrease in V/sub 0c/ with a transformation of the buried homojunction structure to an actual ITO/CdTe heterojunction

Single-event burnout of power MOSFET devices for satellite application

International Nuclear Information System (INIS)

Xue Yuxiong; Tian Kai; Cao Zhou; Yang Shiyu; Liu Gang; Cai Xiaowu; Lu Jiang

2008-01-01

Single-event burnout (SEB) sensitivity was tested for power MOSFET devices, JTMCS081 and JTMCS062, which were made in Institute of Microelectronics, Chinese Academy of Sciences, using californium-252 simulation source. SEB voltage threshold was found for devices under test (DUT). It is helpful for engineers to choose devices used in satellites. (authors)

Radioactive materials production

International Nuclear Information System (INIS)

Anon.

1985-01-01

The Radiochemical Processing Plant (RPP) at ORNL has served as the national repository and distribution center for 233 U for > 20 years. Several hundred kilograms of uranium, containing approximately 90 to 98% 233 U, are stored there in the form of metal, oxides, and nitrate solutions. All of these uranium materials contain small, but significant, concentrations of 232 U, ranging from 2 to 225 ppm. Most of the radioactivity associated with the 233 U comes from the decay daughters of 232 U (74-year half-life). The 252 Cf Industrial Sales/Loan Program involves loans of 252 Cf neutron sources to agencies of the US Government and sales of 252 Cf as the bulk oxide and as palladium-californium alloy pellets and wires. The program has been operated since 1968 in temporary facilities at the Savannah River Laboratory (SRL). The obsolete hot-cell facilities at SRL are now being decommissioned, and the program activities are being transferred to ORNL's Californium Facility in Bldg. 7930, which is managed by the staff of the Transuranium Processing Plant

Validation of the MCNP-DSP Monte Carlo code for calculating source-driven noise parameters of subcritical systems

International Nuclear Information System (INIS)

Valentine, T.E.; Mihalczo, J.T.

1995-01-01

This paper describes calculations performed to validate the modified version of the MCNP code, the MCNP-DSP, used for: the neutron and photon spectra of the spontaneous fission of californium 252; the representation of the detection processes for scattering detectors; the timing of the detection process; and the calculation of the frequency analysis parameters for the MCNP-DSP code

Magnetic measurements of the transuranium elements. Progress report, January 1, 1984-December 31, 1984

International Nuclear Information System (INIS)

Huray, P.G.; Nave, S.E.

1984-01-01

Measurements of the magnetic properties of dhcp californium-249 metal indicated the presence of three regions of differing magnetic character. Additional measurements are also reported. Magnetic moments and valence states of terbium in TbF 3 , BaTbO 3 , and TbO 1 8 are discussed. Progress on high-field operation of the micro-magnetic susceptometer is reported

International Conference on Spin Observables of Nuclear Probes

CERN Document Server

Goodman, Charles; Walker, George; Spin Observables of Nuclear Probes

1988-01-01

The proceedings of the "International Conference on Spin Observables of Nuclear Probes" are presented in this volume. This conference was held in Telluride, Colorado, March 14 -17, 1988, and was the fourth in the Telluride series of nuclear physics conferences. A continuing theme in the Telluride conference series has been the complementarity of various intermediate-energy projectiles for elucidating the nucleon-nucleon interaction and nuclear structure. Earlier conferences have contributed significantly to an understanding of spin currents in nuclei, in particular the distribution of Gamow-Teller strength using charge-exchange reactions. The previous conference on "Antinucleon and Nucleon Nucleus Interactions" compared nuclear information from tra­ tional probes to recent results from antinucleon reactions. The 1988 conference on Spin Observables of Nuclear Probes, put special emphasis on spin observables and brought together experts using spin information to probe nuclear structure. Spin observabl...

Preparation and study of elemental californium-249

International Nuclear Information System (INIS)

Noe, M.; Peterson, J.R.

1975-01-01

Bulk samples of 249 Cf metal were prepared on the 10 μg scale via the Li metal vapor reduction of 249 CfF 3 . Above about 725 0 C elemental Cf exhibits a face-centered cubic (fcc) structure with an average, room-temperature lattice parameter of 5.75(1)A. Between about 600 0 C and 725 0 C, the stable form of Cf metal is another fcc structure with an average, room-temperature lattice parameter of 4.94(1)A. Below 600 0 C metallic Cf exhibits a double hexagonal closest packed (dhcp) structure with average, room temperature lattice parameters of a 0 = 3.39(1)A and c 0 = 11.01(5)A. By comparison of the metallic radii calculated for these three forms with those of the receding transuranium elements, it is suggested that the two, lower temperature modifications represent Cf with a metallic valence of three, while the highest temperature form represents a metallic valence of two. Although the data reported here are from the most complete study to date of elemental Cf, the limitations accompanying such microscale research are duly noted. (U.S.)

Investigation of Thermoelectric Parameters of Bi2Te3: TEGs Assembled using Pressure-Assisted Silver Powder Sintering-Based Joining Technology

Science.gov (United States)

Stranz, Andrej; Waag, Andreas; Peiner, Erwin

2015-06-01

Operation of thermoelectric generator (TEG) modules based on bismuth telluride alloys at temperatures higher than 250°C is mostly limited by the melting point of the assembly solder. Although the thermoelectric parameters of bismuth telluride materials degrade for temperatures >130°C, the power output of the module can be enhanced with an increase in the temperature difference. For this, a temperature-stable joining technique, especially for the hot side of the modules, is required. Fabrication and process parameters of TEG modules consisting of bismuth telluride legs, alumina ceramics and copper interconnects using a joining technique based on pressure-assisted silver powder sintering are described. Measurements of the thermal force, electrical resistance, and output power are presented that were performed for hot side module temperatures up to 350°C and temperature differences higher than 300°C. Temperature cycling and results measured during extended high-temperature operation are addressed.

Reducing the stochasticity of crystal nucleation to enable subnanosecond memory writing

Science.gov (United States)

Rao, Feng; Ding, Keyuan; Zhou, Yuxing; Zheng, Yonghui; Xia, Mengjiao; Lv, Shilong; Song, Zhitang; Feng, Songlin; Ronneberger, Ider; Mazzarello, Riccardo; Zhang, Wei; Ma, Evan

2017-12-01

Operation speed is a key challenge in phase-change random-access memory (PCRAM) technology, especially for achieving subnanosecond high-speed cache memory. Commercialized PCRAM products are limited by the tens of nanoseconds writing speed, originating from the stochastic crystal nucleation during the crystallization of amorphous germanium antimony telluride (Ge2Sb2Te5). Here, we demonstrate an alloying strategy to speed up the crystallization kinetics. The scandium antimony telluride (Sc0.2Sb2Te3) compound that we designed allows a writing speed of only 700 picoseconds without preprogramming in a large conventional PCRAM device. This ultrafast crystallization stems from the reduced stochasticity of nucleation through geometrically matched and robust scandium telluride (ScTe) chemical bonds that stabilize crystal precursors in the amorphous state. Controlling nucleation through alloy design paves the way for the development of cache-type PCRAM technology to boost the working efficiency of computing systems.

Solid-State Neutron Multiplicity Counting System Using Commercial Off-the-Shelf Semiconductor Detectors

Energy Technology Data Exchange (ETDEWEB)

Rozhdestvenskyy, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

2017-08-09

This work iterates on the first demonstration of a solid-state neutron multiplicity counting system developed at Lawrence Livermore National Laboratory by using commercial off-the-shelf detectors. The system was demonstrated to determine the mass of a californium-252 neutron source within 20% error requiring only one-hour measurement time with 20 cm² of active detector area.

Citric complexes of trivalent cerium and berkelium

International Nuclear Information System (INIS)

Boulhassa, S.

1977-01-01

The extraction by thenoyltrifluoroacetone (TTA) in benzene of trivalent cerium, berkelium and californium, at the indicator scale, hydrolysis and complexation by citric acid of these cations are studied. The radionuclides used were 144 Ce, 249 Bk and 249 Cf respectively γ, β and α emitters. The solvent extraction technique of the elements by TTA in benzene from a perchloric medium at the ionic stength 0.1 was employed. The distribution coefficients D were measured by the γ, β or α radiometry. Cerium and berkelium, which have a comparable redox behavior, show in solution a relatively stable valency IV. Therefore the study by solvent extraction of their trivalent form required the standing up of complete reducing conditions of these elements and their stabilization in solution at the valency III. The thermodynamic data obtained for berkelium and californium contribute to understand the chemistry of these elements and permit to complete the third 'tetrad branch' of 5f elements from Cm 3+ to Es 3+ . This tetrad effect is a manifestation of thermodynamic consequence of the 'nephelauxetic effect'. As for Ce(III), the data confirm the pronounced acid property and may be show no neglected ligand effect for f 1 configuration [fr

Directed evolution of the periodic table: probing the electronic structure of late actinides.

Science.gov (United States)

Marsh, M L; Albrecht-Schmitt, T E

2017-07-25

Recent investigations of the coordination chemistry and physical properties of berkelium (Z = 97) and californium (Z = 98) have revealed fundamental differences between post-curium elements and lighter members of the actinide series. This review highlights these developments and chronicles key findings and concepts from the last half-century that have helped usher in a new understanding of the evolution of electronic structure in the periodic table.

Properties of neutron sources

International Nuclear Information System (INIS)

1987-03-01

The Conference presentations were divided into sessions devoted to the following topics: white neutron sources, primarily pulsed (6 papers); fast neutron fields (5 papers); Californium-252 prompt fission neutron spectra (14 papers); monoenergetic sources and filtered beams (11 papers); 14 MeV neutron sources (10 papers); selected special application (one paper); and a general interest session (4 papers). Individual abstracts were prepared separately for the papers

Nanolithography on mercury telluride

International Nuclear Information System (INIS)

Muehlbauer, Mathias Josef

2015-01-01

Topological insulators belong to a new quantum state of matter that is currently one of the most recognized research fields in condensed matter physics. Strained bulk HgTe and HgTe/HgCdTe quantum well structures are currently one of few topological insulator material systems suitable to be studied in transport experiments. In addition HgTe quantum wells provide excellent requirements for the conduction of spintronic experiments. A fundamental requirement for most experiments, however, is to reliably pattern these heterostructures into advanced nano-devices. Nano-lithography on this material system proves to be challenging because of inherent temperature limitations, its high reactivity with various metals and due to its properties as a topological insulator. The current work gives an insight into why many established semiconductor lithography processes cannot be easily transferred to HgTe while providing alternative solutions. The presented developments include novel ohmic contacts, the prevention of metal sidewalls and redeposition fences in combination with low temperature (80 C) lithography and an adapted hardmask lithography process utilizing a sacrificial layer. In addition we demonstrate high resolution low energy (2.5 kV) electron beam lithography and present an alternative airbridge gating technique. The feasibility of nano-structures on HgTe quantum wells is exemplarily verified in two separate transport experiments. We are first to realize physically etched quantum point contacts in HgTe/HgCdTe high mobility 2DEGs and to prove their controllability via external top-gate electrodes. So far quantum point contacts have not been reported in TI materials. However, these constrictions are part of many proposals to probe the nature of the helical quantum spin Hall edge channels and are suggested as injector and detector devices for spin polarized currents. To confirm their functionality we performed four-terminal measurements of the point contact conductance as a function of external gate voltage. Our measurements clearly exhibit quantized conductance steps in 2e"2/h, which is a fundamental characteristic of quantum point contacts. Furthermore we conducted measurements on the formation and control of collimated electron beams, a key feature to realize an all electrical spin-optic device. In a second study several of the newly developed lithography techniques were implemented to produce arrays of nano-wires on inverted and non-inverted HgTe quantum well samples. These devices were used in order to probe and compare the weak antilocalization (WAL) in these structures as a function of magnetic field and temperature. Our measurements reveal that the WAL is almost an order of magnitude larger in inverted samples. This observation is attributed to the Dirac-like dispersion of the energy bands in HgTe quantum wells. The described lithography has already been successfully implemented and adapted in several published studies. All processes have been optimized to guarantee a minimum effect on the heterostructure's properties and the sample surface, which is especially important for probing the topological surface states of strained HgTe bulk layers. Our developments therefore serve as a base for continuous progress to further establish HgTe as a topological insulator and give access to new experiments.

and Cadmium Zinc Telluride

African Journals Online (AJOL)

Bheema

INTRODUCTION. Semiconductor nanoparticles or Quantum Dots (QDs), in particular II-VI materials, have ... the study of structural, electronic transport and optical properties of Zn doped CdTe thin films, ...... Bhattacharya, S.K & Anjali, K. 2007.

Computer-assisted nuclear fuel manufacture

International Nuclear Information System (INIS)

Maloney, J.P.; Schaumann, S.M.; Stone, E.

1976-01-01

At the ERDA Savannah River Plant, a process monitor, which incorporates an online digital computer, assists in manufacturing fuel elements used to produce nuclides such as plutonium, tritium, and californium in the plant's nuclear reactors. Also, inventory functions assist in safeguarding fissile material and protecting against accidental nuclear criticality. Terminals at strategic locations throughout the process area enable production operators to send and receive instructions and information on each manufacturing step

Automated absolute activation analysis with californium-252 sources

International Nuclear Information System (INIS)

MacMurdo, K.W.; Bowman, W.W.

1978-09-01

A 100-mg 252 Cf neutron activation analysis facility is used routinely at the Savannah River Laboratory for multielement analysis of many solid and liquid samples. An absolute analysis technique converts counting data directly to elemental concentration without the use of classical comparative standards and flux monitors. With the totally automated pneumatic sample transfer system, cyclic irradiation-decay-count regimes can be pre-selected for up to 40 samples, and samples can be analyzed with the facility unattended. An automatic data control system starts and stops a high-resolution gamma-ray spectrometer and/or a delayed-neutron detector; the system also stores data and controls output modes. Gamma ray data are reduced by three main programs in the IBM 360/195 computer: the 4096-channel spectrum and pertinent experimental timing, counting, and sample data are stored on magnetic tape; the spectrum is then reduced to a list of significant photopeak energies, integrated areas, and their associated statistical errors; and the third program assigns gamma ray photopeaks to the appropriate neutron activation product(s) by comparing photopeak energies to tabulated gamma ray energies. Photopeak areas are then converted to elemental concentration by using experimental timing and sample data, calculated elemental neutron capture rates, absolute detector efficiencies, and absolute spectroscopic decay data. Calculational procedures have been developed so that fissile material can be analyzed by cyclic neutron activation and delayed-neutron counting procedures. These calculations are based on a 6 half-life group model of delayed neutron emission; calculations include corrections for delayed neutron interference from 17 O. Detection sensitivities of 239 Pu were demonstrated with 15-g samples at a throughput of up to 140 per day. Over 40 elements can be detected at the sub-ppM level

Savannah River Plant californium-252 Shuffler electronics manual

International Nuclear Information System (INIS)

Bourret, S.C.; Crane, T.W.; Eccleston, G.W.; Gallegos, E.A.; Garcia, D.L.

1980-03-01

Detailed information is presented in this report, an electronics manual for the Savannah River Plant Shuffler, about the electronics associated with the various control and data acquisition functions of the Shuffler subsystems. Circuit diagrams, interconnection information, and details about computer control and programming are included

Savannah River Plant Californium-252 Shuffler software manual

International Nuclear Information System (INIS)

Johnson, S.S.; Crane, T.W.; Eccleston, G.W.

1979-03-01

A software manual for operating the Savannah River Plant Shuffler nondestructive assay instrument is presented. The procedures for starting up the instrument, making assays, calibrating, and checking the performance of the hardware units are described. A list of the error messages with an explanation of the circumstances prompting the message and possible corrective measures is given. A summary of the software package is included showing the names and contents of the files and subroutines. The procedure for modifying the software package is outlined

Nanocrystalline CdTe thin films by electrochemical synthesis

Directory of Open Access Journals (Sweden)

Ramesh S. Kapadnis

2013-03-01

Full Text Available Cadmium telluride thin films were deposited onto different substrates as copper, Fluorine-doped tin oxide (FTO, Indium tin oxide (ITO, Aluminum and zinc at room temperature via electrochemical route. The morphology of the film shows the nanostructures on the deposited surface of the films and their growth in vertical direction. Different nanostructures developed on different substrates. The X-ray diffraction study reveals that the deposited films are nanocrystalline in nature. UV-Visible absorption spectrum shows the wide range of absorption in the visible region. Energy-dispersive spectroscopy confirms the formation of cadmium telluride.

Characterization of CdZnTe ambient temperature detectors

International Nuclear Information System (INIS)

Lavietes, A.

1994-09-01

A great deal of interest has been generated in the use of cadmium telluride (CdTe) and cadmium zinc telluride (CdZnTe) detectors for ambient temperature detection of radionuclides. The addition of zinc to CdTe provides several benefits that enhance the materials operational characteristics at ambient temperature. Recent movement in the industry is to produce larger volume detectors using CdZnTe without much known about the effects of larger geometry on performance. The purpose of this study is to get an idea of the relationship of detector performance to both area and thickness variations

Preparation and characterization of ZnTe thin films by SILAR method

International Nuclear Information System (INIS)

Kale, S.S.; Mane, R.S.; Pathan, H.M.; Shaikh, A.V.; Joo, Oh-Shim; Han, Sung-Hwan

2007-01-01

Nanocrystalline zinc telluride (ZnTe) thin films were prepared by using successive ionic layer adsorption and reaction (SILAR) method from aqueous solutions of zinc sulfate and sodium telluride. The films were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive X-ray analysis and optical absorption measurement techniques. The synthesized ZnTe thin films were nanocrystalline with densely aggregated particles in nanometer scale and were free from the voids or cracks. The optical band gap energy of the film was found to be thickness dependent. The elemental chemical compositional stoichiometric analysis revealed good Zn:Te elemental ratio of 53:47

CdTe/CZT under high flux irradiation

International Nuclear Information System (INIS)

Strassburg, Matthias; Schroeter, Christian; Hackenschmied, Peter

2011-01-01

Direct converting quantum counting detectors based on cadmium telluride and cadmium zinc telluride have been investigated with respect to their properties under intense X-ray irradiation. To derive a detailed picture of the performance of such detectors, the influence of the electric field, the detector thickness, the temperature and the intensity of the X-ray irradiation was studied. The results are discussed in terms of the ''polarization'' phenomenon, a reduction of the electric field strength inside the detector due to immobile charge carriers accumulating during irradiation. Furthermore, the impact of Te-inclusions and -precipitates is presented.

Radiation resistance of thin-film solar cells for space photovoltaic power

Science.gov (United States)

Woodyard, James R.; Landis, Geoffrey A.

1991-01-01

Copper indium diselenide, cadmium telluride, and amorphous silicon alloy solar cells have achieved noteworthy performance and are currently being studied for space power applications. Cadmium sulfide cells had been the subject of much effort but are no longer considered for space applications. A review is presented of what is known about the radiation degradation of thin film solar cells in space. Experimental cadmium telluride and amorphous silicon alloy cells are reviewed. Damage mechanisms and radiation induced defect generation and passivation in the amorphous silicon alloy cell are discussed in detail due to the greater amount of experimental data available.

Computer-assisted nuclear fuel manufacture

International Nuclear Information System (INIS)

Maloney, J.P.; Schaumann, C.M.; Stone, E.

1976-06-01

At the ERDA Savannah River Plant, a process monitor, which incorporates an online digital computer, assists in manufacturing fuel elements used to produce nuclides such as plutonium, tritium, and californium in the plant's nuclear reactors. Also, inventory functions assist in safeguarding fissile material and protecting against accidental nuclear criticality. Terminals at strategic locations throughout the process area enable production operators to send and receive instructions and information on each manufacturing step. 11 fig

Nanostructured silicon for thermoelectric

Science.gov (United States)

Stranz, A.; Kähler, J.; Waag, A.; Peiner, E.

2011-06-01

Thermoelectric modules convert thermal energy into electrical energy and vice versa. At present bismuth telluride is the most widely commercial used material for thermoelectric energy conversion. There are many applications where bismuth telluride modules are installed, mainly for refrigeration. However, bismuth telluride as material for energy generation in large scale has some disadvantages. Its availability is limited, it is hot stable at higher temperatures (>250°C) and manufacturing cost is relatively high. An alternative material for energy conversion in the future could be silicon. The technological processing of silicon is well advanced due to the rapid development of microelectronics in recent years. Silicon is largely available and environmentally friendly. The operating temperature of silicon thermoelectric generators can be much higher than of bismuth telluride. Today silicon is rarely used as a thermoelectric material because of its high thermal conductivity. In order to use silicon as an efficient thermoelectric material, it is necessary to reduce its thermal conductivity, while maintaining high electrical conductivity and high Seebeck coefficient. This can be done by nanostructuring into arrays of pillars. Fabrication of silicon pillars using ICP-cryogenic dry etching (Inductive Coupled Plasma) will be described. Their uniform height of the pillars allows simultaneous connecting of all pillars of an array. The pillars have diameters down to 180 nm and their height was selected between 1 micron and 10 microns. Measurement of electrical resistance of single silicon pillars will be presented which is done in a scanning electron microscope (SEM) equipped with nanomanipulators. Furthermore, measurement of thermal conductivity of single pillars with different diameters using the 3ω method will be shown.

The protective cell petrus for the production of californium 252; Cellule blindee petrus pour la production et l'etude du californium 252

Energy Technology Data Exchange (ETDEWEB)

Sontag, R; Berger, R [Commissariat a l' Energie Atomique, Fontenay-aux-Roses (France). Centre d' Etudes Nucleaires

1967-07-01

The alpha, beta, gamma, neutron cell which is described in the present paper is devoted to the transplutonium element production and study. It is located at the CEN in Fontenay-aux-Roses (France). The 4 feet ordinary concrete shielding made of stacked blocs allows the manipulation of radioactive sources as high as 1000 curies of 1 MeV gamma rays and with a fast neutrons flux of 10{sup 9} n.cm{sup -2}.s{sup -1}. The airtight alpha containment box is equipped with two transfer systems, one consists of a parallelepiped shaped airtight box located in a turntable, the other uses standard cylindrical containers made of polyethylene. The general equipment and the main setting up are also described. (authors) [French] La cellule alpha, beta, gamma, neutron, qui fait l'objet du present article, est destinee a la production et a l'etude des elements transplutoniens. Elle est construite au C.E.N. de Fontenay-aux-Roses (France). La protection biologique, calculee pour une activite de 1000 curies de rayonnement gamma d'energie 1 MeV accompagnee d'un flux de neutrons rapides de 10{sup 9}/cm{sup 2}s, est constituee par des parois en beton de 1,20 m d'epaisseur. L'enceinte alpha est une boite etanche qui comporte devx systemes de transferts: l'un consiste en une boite parallelepipedique etanche logee dans un barillet, l'autre fait appel a des recipients cylindriques standard en polyethylene. L'equipement general et les installations les plus importantes sont ensuite decrits. (auteurs)

Mixed nickel-gallium tellurides Ni{sub 3−x}GaTe{sub 2} as a matrix for incorporating magnetic cations: A Ni{sub 3−x}Fe{sub x}GaTe{sub 2} series

Energy Technology Data Exchange (ETDEWEB)

Kuznetsov, Alexey N., E-mail: alexei@inorg.chem.msu.ru [Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1-3, GSP-1, 119991 Moscow (Russian Federation); N.S. Kurnakov Institute of General and Inorganic Chemistry, RAS, Leninsky pr. 31, GSP-1, 119991 Moscow (Russian Federation); Stroganova, Ekaterina A.; Zakharova, Elena Yu; Solopchenko, Alexander V.; Sobolev, Alexey V.; Presniakov, Igor A. [Department of Chemistry, Lomonosov Moscow State University, Leninskie Gory 1-3, GSP-1, 119991 Moscow (Russian Federation); Kirdyankin, Denis I.; Novotortsev, Vladimir M. [N.S. Kurnakov Institute of General and Inorganic Chemistry, RAS, Leninsky pr. 31, GSP-1, 119991 Moscow (Russian Federation)

2017-06-15

Using a high-temperature ampoule technique, a series of mixed nickel-iron-gallium metal-rich tellurides with layered structures, Ni{sub 3-x}Fe{sub x}GaTe{sub 2}, were prepared and characterized based on X-ray powder diffraction, energy-dispersive spectroscopy, and {sup 57}Fe Mössbauer spectroscopy data. These compounds may be regarded as a result of partial substitution of nickel by iron in the recently reported ternary Ni{sub 3-x}GaTe{sub 2} series, which are based on NiAs/Ni{sub 2}In type of structure. The compositional boundary for the substitution was found to be at x~1. According to the Mössbauer spectroscopy data, the substitution is not statistical, and iron atoms with the increase in x tend to preferentially occupy those nickel positions that are partially vacant in the initial ternary compound. Magnetic measurements data for the Ni{sub 3-x}Fe{sub x}GaTe{sub 2} series show dramatic change in behavior from temperature-independent paramagnetic properties of the initial matrix to a low-temperature (~75 K) ferromagnetic ordering in the Ni{sub 2}FeGaTe{sub 2}. - Graphical abstract: Ordered substitution of nickel by iron in the Ni{sub 3−x}GaTe{sub 2} series leading to ferromagnetic ordering. - Highlights: • A series of Ni{sub 3−x}Fe{sub x}GaTe{sub 2} compounds were synthesized. • They adopt the NiAs/Ni{sub 2}In type of structure with ordered iron distribution. • The distribution of iron was studied using {sup 57}Fe Mössbauer spectroscopy. • An increase in iron content leads to the strong ferromagnetic coupling.

Thermoelectric Coolers with Sintered Silver Interconnects

Science.gov (United States)

Kähler, Julian; Stranz, Andrej; Waag, Andreas; Peiner, Erwin

2014-06-01

The fabrication and performance of a sintered Peltier cooler (SPC) based on bismuth telluride with sintered silver interconnects are described. Miniature SPC modules with a footprint of 20 mm2 were assembled using pick-and-place pressure-assisted silver sintering at low pressure (5.5 N/mm2) and moderate temperature (250°C to 270°C). A modified flip-chip bonder combined with screen/stencil printing for paste transfer was used for the pick-and-place process, enabling high positioning accuracy, easy handling of the tiny bismuth telluride pellets, and immediate visual process control. A specific contact resistance of (1.4 ± 0.1) × 10-5 Ω cm2 was found, which is in the range of values reported for high-temperature solder interconnects of bismuth telluride pellets. The realized SPCs were evaluated from room temperature to 300°C, considerably outperforming the operating temperature range of standard commercial Peltier coolers. Temperature cycling capability was investigated from 100°C to 235°C over more than 200 h, i.e., 850 cycles, during which no degradation of module resistance or cooling performance occurred.

Heavy ion tests on programmable VLSI

International Nuclear Information System (INIS)

Provost-Grellier, A.

1989-11-01

The radiation from space environment induces operation damages in onboard computers systems. The definition of a strategy, for the Very Large Scale Integrated Circuitry (VLSI) qualification and choice, is needed. The 'upset' phenomena is known to be the most critical integrated circuit radiation effect. The strategies for testing integrated circuits are reviewed. A method and a test device were developed and applied to space applications candidate circuits. Cyclotron, synchrotron and Californium source experiments were carried out [fr

Charge breeding of radioactive isotopes at the CARIBU facility with an electron beam ion source

Science.gov (United States)

Vondrasek, R. C.; Dickerson, C. A.; Hendricks, M.; Ostroumov, P.; Pardo, R.; Savard, G.; Scott, R.; Zinkann, G.

2018-05-01

An Electron Beam Ion Source Charge Breeder (EBIS-CB) has been developed at Argonne National Laboratory as part of the californium rare ion breeder upgrade. For the past year, the EBIS-CB has been undergoing commissioning as part of the ATLAS accelerator complex. It has delivered both stable and radioactive beams with A/Q 18% into a single charge state. The operation of this device, challenges during the commissioning phase, and future improvements will be discussed.

Safety analysis report for packaging: neutron shipping cask, model 0.5T

International Nuclear Information System (INIS)

Peterson, R.T.

1976-01-01

The Safety Analysis Report for Packaging demonstrates that the neutron shipping cask can safely transport, in solid or powder form, all isotopes of uranium, plutonium, americium, curium, berkelium, californium, einsteinium, and fermium. The shipping cask and its contents are described. It also evaluates transport conditions, structural parameters (e.g., load resistance, pressure and impact effects, lifting and tiedown devices), and shielding. Finally, it discusses compliance with Chapter 0529 of the Energy Research and Development Administration Manual

NWIS casting measurements taken during demonstrations to Russian visitors

International Nuclear Information System (INIS)

Mullens, J.A.; Valentine, T.E.; Mihalczo, J.T.

1998-01-01

This report describes a set of NWIS measurements made during demonstrations to Russian visitors on August 28, 1997. These measurements will be given to the Russian visitors from Arzamus-16 as part of their NWIS training (part of a DOE laboratory-to-laboratory exchange program). These measurements are made on standard highly enriched Uranium annular castings (as used for storage). Associated NWIS calibration runs were made in air (no casting, just the NWIS Californium source and detectors)

Health physics aspects of 252Cf

International Nuclear Information System (INIS)

Bhagwat, A.M.

1974-01-01

After briefly describing the methods of production, radioactive, chemical and biological properties of californium-252, its health physics aspects are reviewed in detail. Its external and internal radiation hazards can be minimised through control of radiation and contamination and proper shield design. Use of various shielding materials is evaluated. The following aspects are also discussed : (1) radiation detectors for neutrons and gamma radiation (2) personnel monitoring techniques (3) bioassay and (4) storage and transportation. (M.G.B.)

Survey of potential markets for devices using Californium-252

International Nuclear Information System (INIS)

Permar, P.H.

1975-01-01

Potential applications for devices or systems containing 252 Cf in the years from 1975 to 1980 are estimated. The estimated number of devices and associated business value were derived from a survey of 46 industrial, educational and governmental organizations conducted from Jan. to May, 1975. Applications for devices and systems based on 252 Cf are expected to increase by a factor of 7 in the 6-y period from 1975 to 1980. The annual business value of 252 Cf devices should increase from 1.5 million dollars in 1975 to 10.8 million dollars in 1980. The potential European market should be several times as large as the US market, based on actual sales of 252 Cf, which have been two to four times greater in Europe than in the US

Californium-252 interstitial implants in carcinoma of the tongue

International Nuclear Information System (INIS)

Vtyurin, B.M.; Ivanov, V.N.; Medvedev, V.S.; Galantseva, G.F.; Abdulkadyrov, S.A.; Ivanova, L.F.; Petrovskaya, G.A.; Plichko, V.I.

1985-01-01

A clinical study using 252 Cf sources in brachytherapy of tumors began in the Research Institute of Medical Radiology of the Academy of Medical Sciences of the USSR in 1973. 252 Cf afterloading cells were utilized by the method of simple afterloading. Dosimetry and radiation protection of medical personnel were developed. To substantiate optimal therapeutic doses of 252 Cf neutrons, a correlation of dose, time, and treatment volume factors with clinical results of 252 Cf interstitial implants in carcinoma of the tongue for 47 patients with a minimum follow-up period of 1 year was studied. Forty-nine interstitial implants have been performed. Seventeen patients received 252 Cf implants alone (Group I), 17 other patients received 252 Cf implants in combination with external radiation (Group II), and 15 patients were treated with interstitial implants for recurrent or residual tumors (Groups III). Complete regression of carcinoma of the tongue was obtained in 48 patients (98%). Thirteen patients (27%) developed radiation necrosis. The therapeutic dose of neutron radiation from 252 Cf sources in interstitial radiotherapy of primary tongue carcinomas (Group I) was found to be 7 to 9 Gy. Optimal therapeutic neutron dose in combined interstitial and external radiotherapy of primary tumors (Group II) was 5 to 6 Gy with an external radiation dose of 40 Gy. For recurrent and residual tumors (Group III), favorable results were obtained with tumor doses of 6.5 to 7 Gy

Undergraduate experiments using the neutron radiation from californium-252

International Nuclear Information System (INIS)

Rossel, J.; Golecki, I.

1976-01-01

Three experiments designed to demonstrate and measure several properties of the neutron radiation emitted by a 3μg 252 Cf source are described. The experiments constitute a special project carried out by a third-year undergraduate student at the Institute of Physics of the University of Neuchatel. The 252 Cf source is enclosed in a shield which allows a pencil of fast neutrons to pass through a central tube, while reducing the ambient radiation below the tolerance level. The shield consists of layers of borated paraffin wax, iron and cadmium. The first experiment uses an air-alcohol diffusion cloud chamber for the demonstration of tracks of recoil protons produced by the neutrons. Semi-quantitative measurements of track lengths give the correct order of magnitude of the proton energies. In the second experiment a liquid scintillator detector is used to scan the beam profile across the radiation shield enclosing the source. A pulse-shape-discrimination system discriminates between neutrons and gamma photons. The third experiment makes use of the nuclear emulsion technique to study the neutron energy distribution of 252 Cf. Preliminary results are compared with published values. (author)

Effect of composition on the degree of anisotropy of thermal expansion and electric resistance of cermet specimens of GeTe

International Nuclear Information System (INIS)

Barbakadze, K.G.; Vekua, T.S.; Ioseliani, M.I.; Kvitsiniya, K.M.

1988-01-01

A study was made on α temperature coefficient of thermal expansion and ρ specific electric resistance of cermet germanium telluride for alloys close to stoichiometric composition. It is shown that anisotropy of thermal expansion of cermet germanium telluride depends sufficiently on its composition. This dependence is clearly pronounced if tellurium content in alloys equals 50.4-51.2 at.%. The maximal anisotropy is observed in the alloy containing 50.8 at.% of tellurium. The temperature of extreme value of temperature coefficient of linear expansion decreases from 440 down to 373 deg.C for alloys with 49-50.8 at.% of tellurium, and grows from 373 up to 405 deg.C if tellurium content equals 50.8-52 at.%

Status of tellurium--hastelloy N studies in molten fluoride salts

International Nuclear Information System (INIS)

Keiser, J.R.

1977-10-01

Tellurium, which is a fission product in nuclear reactor fuels, can embrittle the surface grain boundaries of nickel-base structural materials. This report summarizes results of an experimental investigation conducted to understand the mechanism and to develop a means of controlling this embrittlement in the alloy Hastelloy N. The addition of a chromium telluride to salt can be used to provide small partial pressures of tellurium simulating a reactor environment where tellurium appears as a fission product. The intergranular embrittlement produced in Hastelloy N when exposed to this chromium telluride-salt mixture can be reduced by adding niobium to the Hastelloy N or by controlling the oxidation potential of the salt in the reducing range

Power generation from thermoelectric system-embedded Plexiglas for green building technology

KAUST Repository

Inayat, Salman Bin

2012-06-09

Thermoelectric materials embedded through or inside exterior glass windows can act as a viable source of supplemental power in geographic locations where hot weather dominates. This thermoelectricity is generated because of the thermal difference between the high temperature outside and the relatively cold temperature inside. Using physical vapor deposition process, we experimentally verify this concept by embedding bismuth telluride and antimony telluride through the 5 mm Plexiglas to demonstrate 10 nW of thermopower generation with a temperature gradient of 21 °C. Albeit tiny at this point with non-optimized design and development, this concept can be extended for relatively large-scale power generation as an additional power supply for green building technology.

From Selenium- to Tellurium-Based Glass Optical Fibers for Infrared Spectroscopies

Directory of Open Access Journals (Sweden)

Jacques Lucas

2013-05-01

Full Text Available Chalcogenide glasses are based on sulfur, selenium and tellurium elements, and have been studied for several decades regarding different applications. Among them, selenide glasses exhibit excellent infrared transmission in the 1 to 15 µm region. Due to their good thermo-mechanical properties, these glasses could be easily shaped into optical devices such as lenses and optical fibers. During the past decade of research, selenide glass fibers have been proved to be suitable for infrared sensing in an original spectroscopic method named Fiber Evanescent Wave Spectroscopy (FEWS. FEWS has provided very nice and promising results, for example for medical diagnosis. Then, some sophisticated fibers, also based on selenide glasses, were developed: rare-earth doped fibers and microstructured fibers. In parallel, the study of telluride glasses, which can have transmission up to 28 µm due to its atom heaviness, has been intensified thanks to the DARWIN mission led by the European Space Agency (ESA. The development of telluride glass fiber enables a successful observation of CO2 absorption band located around 15 µm. In this paper we review recent results obtained in the Glass and Ceramics Laboratory at Rennes on the development of selenide to telluride glass optical fibers, and their use for spectroscopy from the mid to the far infrared ranges.

Safety analysis report for packaging: neutron shipping cask, model 4T

International Nuclear Information System (INIS)

Peterson, R.T.

1977-01-01

This Safety Analysis Report for Packaging demonstrates that the neutron shipping cask can safely transport, in solid or powder form, all isotopes of uranium, plutonium, americium, curium, berkelium, californium, einsteinium, and fermium. The cask and its contents are described. It also evaluates transport conditions, structural parameters (e.g., load resistance, pressure and impact effects, lifting and tiedown devices), and shielding. Finally, it discusses compliance with Chapter 0529 of the Energy Research and Development Administration Manual, Safety Standards for the Packaging of Fissile and Other Radioactive Materials

A Neutron Study for Phonon Dispersion Relations in HgTe

DEFF Research Database (Denmark)

Kepa, H.; Gebicki, W.; Giebultowicz, T.

1980-01-01

Dispersion relations for acoustic phonons in mercury telluride in three high symmetry directions [111], [110] and [001] are presented. The eleven-parameter rigid-ion model is fitted to the experimental data....

Method for measuring multiple scattering corrections between liquid scintillators

Energy Technology Data Exchange (ETDEWEB)

Verbeke, J.M., E-mail: verbeke2@llnl.gov; Glenn, A.M., E-mail: glenn22@llnl.gov; Keefer, G.J., E-mail: keefer1@llnl.gov; Wurtz, R.E., E-mail: wurtz1@llnl.gov

2016-07-21

A time-of-flight method is proposed to experimentally quantify the fractions of neutrons scattering between scintillators. An array of scintillators is characterized in terms of crosstalk with this method by measuring a californium source, for different neutron energy thresholds. The spectral information recorded by the scintillators can be used to estimate the fractions of neutrons multiple scattering. With the help of a correction to Feynman's point model theory to account for multiple scattering, these fractions can in turn improve the mass reconstruction of fissile materials under investigation.

Nuclear assay of coal. Volume 1. Coal composition by prompt neutron activation analysis: basic experiments. Final report

International Nuclear Information System (INIS)

Reynolds, G.; Bozorganesh, H.; Elias, E.; Gozani, T.; Maung, T.; Orphan, V.

1979-01-01

Using californium-252 as a source of exciting neutrons, prompt gamma photons emitted by elemental nuclei in the coal have been measured using several detectors, including sodium--iodide and germanium--lithium. Several coal types, including bituminous, subbituminous lignite and anthracite were crushed to various top sizes and analyzed carefully be traditional ASTM wet chemistry techniques at two or three different laboratories. The elements (sulfur, hydrogen, carbon, aluminum, silicon, iron, calcium, sodium, nitrogen, and chlorine) were determined by prompt neutron activations and the quantities compared with those of the wet chemical analyses

Actinides

International Nuclear Information System (INIS)

Martinot, L.; Fuger, J.

1985-01-01

The oxidation behavior of the actinides is explained on the basis of their electronic structure. The actinide elements, actinium, thorium, protactinium, uranium, neptunium, plutonium, americium, curium, berkelium, californium, einsteinium, fermium, mendelevium, nobelium, and laurencium are included. For all except the last three elements, the points of discussion are oxidation states, Gibbs energies and potentials, and potential diagram for the element in acid solution; and thermodynamic properties of these same elements are tabulated. References are cited following discussion of each element with a total of 97 references being cited. 13 tables

Alberi Validates New Theory, Sheds Light on Semiconductors | News | NREL

Science.gov (United States)

(cadmium telluride), and GaN (gallium nitride), which are used for cell phones, solar panels, and LED suppressing defects with light, which may allow higher efficiencies in solar panels, greater lifespan for LED

Impacting Innovation and Commercialization: NREL's Partnering Facilities

Science.gov (United States)

pioneer cadmium telluride (CdTe) solar panels with industry. DOE recognized the lab's role, and NREL's deposits uniform layers of semiconductor material for solar panels, won a 2003 R&D100 Award and was

Solid-state cadmium telluride radiation detector

Energy Technology Data Exchange (ETDEWEB)

Takeuchi, Yoji; Kitamoto, Hisashi; Hosomatsu, Haruo

1984-09-01

The growth of CdTe single crystal and its application to CdTe detector array was studied for X-ray computed tomography (XCT) equipment. A p-type CdTe single crystal with 10/sup 4/ ohm.cm specific resistivity was grown in a quartz ampoule under vapor pressure control of Cd in a vertical Bridgman furnace. An 18-element detector array was fabricated with this single crystal. The detector was operated with no bias and the sensitivity was confirmed to be between 2.8 x 10/sup -12/ and 14 x 10/sup -12/ A.h/(R.mm/sup 2/). Commercial CdTe single crystal was used to manufacture as 560-element detector array for XCT. Results show that CdTe detector is sensitive, linear and has high resolution.

Nonelastic electron scattering in mercury telluride

CERN Document Server

Malik, O P

2002-01-01

By exact solution of the Boltzmann equation, the nonequilibrium charge carrier distribution function is obtained. In the temperature range 4.2 - 300 K, main electron scattering mechanisms are considered by taking into account the nonelastic electron interaction with optical vibrations of the crystal lattice.

The protective cell petrus for the production of californium 252

International Nuclear Information System (INIS)

Sontag, R.; Berger, R.

1967-01-01

The alpha, beta, gamma, neutron cell which is described in the present paper is devoted to the transplutonium element production and study. It is located at the CEN in Fontenay-aux-Roses (France). The 4 feet ordinary concrete shielding made of stacked blocs allows the manipulation of radioactive sources as high as 1000 curies of 1 MeV gamma rays and with a fast neutrons flux of 10 9 n.cm -2 .s -1 . The airtight alpha containment box is equipped with two transfer systems, one consists of a parallelepiped shaped airtight box located in a turntable, the other uses standard cylindrical containers made of polyethylene. The general equipment and the main setting up are also described. (authors) [fr

Optimization of CZT Detectors with Sub-mm Pixel Pitches Project

Data.gov (United States)

National Aeronautics and Space Administration — We propose to develop and optimize 0.5 cm thick Cadmium Zinc Telluride (CZT) detectors with very small pixel pitches, i.e. 350 micron and 600 micron. The proposed...

Thermoelectric properties and nonstoichiometry of GaGeTe

Czech Academy of Sciences Publication Activity Database

Drašar, Č.; Kucek, V.; Beneš, L.; Lošťák, P.; Vlček, Milan

2012-01-01

Roč. 193, SI (2012), s. 42-46 ISSN 0022-4596 Institutional research plan: CEZ:AV0Z40500505 Keywords : gallium germanium telluride * thermoelectric properties * stoichiometry Subject RIV: CA - Inorganic Chemistry Impact factor: 2.040, year: 2012

Recursos y alternativas de tratamiento para los minerales de teluro de Sonora (México

Directory of Open Access Journals (Sweden)

Aguayo, S.

1996-02-01

Full Text Available Tellurium production is limited mainly to that obtained from the treatment of electrolyte muds from copper refineries. However, there are several other sources from which the precious metal tellurides are potentially attractive. This work presents a review of the main localities in Sonora (México, where tellurides have been found. In addition, based upon the physical chemistry fundamentals for tellurium and precious metal tellurides, the aqueous extraction and recovery routes are discussed.

El teluro es un elemento escaso, pero con un espectro amplio de aplicaciones. Su producción está limitada a la obtenida por el tratamiento de los lodos electrolíticos de las refinerías de cobre. De las fuentes alternativas de teluro, los telururos de metales preciosos son atractivos por la asociación natural de estos dos elementos, con la posibilidad de obtener el teluro como subproducto. Sonora (México, se caracteriza por ser una zona rica en teluros con más de treinta especies registradas. Este artículo describe las principales localizaciones en que se encuentran minerales de teluro en Sonora (México, señalando sus principales características, así como las especies hasta ahora registradas. Se analizan, además, las posibles rutas de extracción y recuperación acuosa de teluro, de acuerdo con la fisicoquímica de los sistemas teluro-metales preciosos.

Spectrometry of X-ray beams using Cadmium and Zinc Teluride detector

International Nuclear Information System (INIS)

Becker, Paulo Henriques Bastos

1997-06-01

Determination of X-ray spectra to be utilized for medical diagnostics is a complementary process to the development of procedures to be applied to the quality control of radiodiagnostics X-ray equipment. Until some years ago, that was only possible using Germanium or Silicon detectors. Both have an excellent resolution in this energy range, but present also some restrictions as there are high costs and the necessity of operating them at temperature of liquid Nitrogen, which is not always available at the measurement's place. Room temperature detectors like Cadmium Telluride and Mercury Iodine don't have these restrictions. They, however, have a lower resolution and incomplete collection of the charges produced by their interaction with radiation. With technological advance of crystal growth in general and new techniques like cooling the crystal with a Peltier cell and rise time discrimination circuits, today Cadmium Telluride detectors show a resolution very close to that from Germanium detectors. This work relates to the routine use of Cadmium and Zinc Telluride detectors for measuring X-ray spectra in loco of diagnostic X-ray units. It characterizes the properties of a commercially available detector and offers a model for stripping the measured pulse height distribution. It was also developed a collimator to allow the direct measurement of the beam. The model developed and the constructed set-up were applied to two X-ray tubes and the achieved spectra compared with some spectra available from the literature. (author)

Phenomenon of ''self-cleaning'' of crystals

International Nuclear Information System (INIS)

Matveev, O.A.; Arkad'eva, E.N.; Goncharov, L.A.

1975-01-01

Crystals of germanium and cadmium telluride have been produced having the characteristics corresponding to the low content of electrically active impurities and crystal defects. The crystals have been grown under conditions of an equilibrium diffusion-concentration interaction of the impurities and crystal defects, with the donor alloying and controlling the acceptors concentration. These crystals have been studied with the help of the mass-spectral analysis, the Hall effect, photoelectroscopy, spectral photoconductivity and losses of collection of a charge from an ionizing particle on gamma-detectors fabricated of the crystals. Herein the doped composition of the crystals has been determined, the concentrations of the shallow and deep acceptors and donors have been measured separately, the life-times of the electrons and holes have been measured, the energetic position and the concentration of the carrier capture levels have been determined. The crystals grown possess all the characteristic features of rather pure crystals. The results of the mass-spectral analysis have shown that in the cadmium telluride crystals the impurities are present within 10 14 to 10 17 cm -3 . Therefore, a deep ''self-refining'' of the crystal takes place, which proceeds by means of deactivation of the electrically active centers with their associating into electrically inactive complexes. Thus a fact of the deep ''self-refining'' of germanium- and cadmium telluride crystals is stated. It is presumed that such a ''self-refining'' can actually proceed practically in all the crystals

Thermoelectric micro converters for cooling and energy-scavenging systems

International Nuclear Information System (INIS)

Goncalves, L M; Couto, C; Correia, J H; Alpuim, P

2008-01-01

This paper describes the fabrication process of thermoelectric microconverters, based on n-type bismuth telluride (Bi 2 Te 3 ) and p-type antimony telluride (Sb 2 Te 3 ) thin films. The films are fabricated by thermal co-evaporation with thermoelectric properties comparable to those reported for the same materials in bulk form (used in conventional macro-scale Peltier modules). The absolute value of the Seebeck coefficient in the range of 150–250 µV K −1 and an in-plane electrical resistivity of 7–15 µΩ m were obtained. The influence of fabrication parameters on thermoelectric properties is reported. The films were patterned by photolithography and wet-etching techniques, using HNO 3 /HCl-based etchants. The influence of composition and concentration of etchants in the lithographic process is reported. A microcooler was fabricated

Miniature gamma-ray camera for tumor localization

International Nuclear Information System (INIS)

Lund, J.C.; Olsen, R.W.; James, R.B.; Cross, E.

1997-08-01

The overall goal of this LDRD project was to develop technology for a miniature gamma-ray camera for use in nuclear medicine. The camera will meet a need of the medical community for an improved means to image radio-pharmaceuticals in the body. In addition, this technology-with only slight modifications-should prove useful in applications requiring the monitoring and verification of special nuclear materials (SNMs). Utilization of the good energy resolution of mercuric iodide and cadmium zinc telluride detectors provides a means for rejecting scattered gamma-rays and improving the isotopic selectivity in gamma-ray images. The first year of this project involved fabrication and testing of a monolithic mercuric iodide and cadmium zinc telluride detector arrays and appropriate collimators/apertures. The second year of the program involved integration of the front-end detector module, pulse processing electronics, computer, software, and display

Radiation protection data sheet. Radiation protection data sheets for the use of radionuclides in unsealed sources

International Nuclear Information System (INIS)

Anon.

1999-01-01

These radiation protection data sheet are devoted to responsible persons and employees of various laboratories or medical, pharmaceutical, university and industrial departments where radionuclides are handled as well as all the persons who attend to satisfy in this field. They contain the essential radiation protection data for the use of unsealed sources: physical characteristics, risk assessment, administrative procedures, recommendations, regulations and bibliography. This new series includes the following radionuclides: californium 252, curium 244, gallium 67, indium 113m, plutonium 238, plutonium 239, polonium 210, potassium 42, radium 226, thorium 232, uranium 238 and zinc 65. (O.M.)

Determination of the relative power density distribution in a heterogeneous reactor from the results of measurements of the reactivity effects and the neutron importance function

International Nuclear Information System (INIS)

Bobrov, A. A.; Glushkov, E. S.; Zimin, A. A.; Kapitonova, A. V.; Kompaniets, G. V.; Nosov, V. I.; Petrushenko, R. P.; Smirnov, O. N.

2012-01-01

A method for experimental determination of the relative power density distribution in a heterogeneous reactor based on measurements of fuel reactivity effects and importance of neutrons from a californium source is proposed. The method was perfected on two critical assembly configurations at the NARCISS facility of the Kurchatov Institute, which simulated a small-size heterogeneous nuclear reactor. The neutron importance measurements were performed on subcritical and critical assemblies. It is shown that, along with traditionally used activation methods, the developed method can be applied to experimental studies of special features of the power density distribution in critical assemblies and reactors.

Effect of increasing tellurium content on the electronic and optical properties of cadmium selenide telluride alloys CdSe{sub 1-x}Te{sub x}: An ab initio study

Energy Technology Data Exchange (ETDEWEB)

Reshak, Ali Hussain, E-mail: maalidph@yahoo.co.uk [Institute of Physical Biology-South Bohemia University, Nove Hrady 37333 (Czech Republic); School of Material Engineering, Malaysia University of Perlis, P.O Box 77, d/a Pejabat Pos Besar, 01007 Kangar, Perlis (Malaysia); Kityk, I.V. [Electrical Engineering Department, Technical University of Czestochowa, Al. Armii Krajowej 17/19, Czestochowa (Poland); Khenata, R. [Laboratoire de Physique Quantique et de Modelisation Mathematique de la Matiere (LPQ3 M), universite de Mascara, Mascara 29000 (Algeria); Department of Physics and Astronomy, King Saud University, P.O. Box 2455, Riyadh 11451 (Saudi Arabia); Auluck, S. [National Physical Laboratory Dr. K S Krishnan Marg, New Delhi 110012 (India)

2011-06-16

Highlights: > Theoretical study of effect of vary Te content on band structure, density of states, linear and nonlinear optical susceptibilities of CdSe{sub 1-x}Te{sub x}. > Increasing Te content leads to a decrease in the energy band gap. > Significant enhancement of the electronic properties as a function of tellurium concentration - Abstract: An all electron full potential linearized augmented plane wave method, within a framework of GGA (EV-GGA) approach, has been used for an ab initio theoretical study of the effect of increasing tellurium content on the band structure, density of states, and the spectral features of the linear and nonlinear optical susceptibilities of the cadmium-selenide-telluride ternary alloys CdSe{sub 1-x}Te{sub x} (x = 0.0, 0.25, 0.5, 0.75 and 1.0). Our calculations show that increasing Te content leads to a decrease in the energy band gap. We find that the band gaps are 0.95 (1.76), 0.89 (1.65), 0.83 (1.56), 0.79 (1.44) and 0.76 (1.31) eV for x = 0.0, 0.25, 0.5, 0.75 and 1.0 in the cubic structure. As these alloys are known to have a wurtzite structure for x less than 0.25, the energy gaps are 0.8 (1.6) eV and 0.7 (1.55) eV for the wurtzite structure (x = 0.0, 0.25) for the GGA (EV-GGA) exchange correlation potentials. This reduction in the energy gaps enhances the functionality of the CdSe{sub 1-x}Te{sub x} alloys, at least for these concentrations, leading to an increase in the effective second-order susceptibility coefficients from 16.75 pm/V (CdSe) to 18.85 pm/V (CdSe{sub 0.75}Te{sub 0.25}), 27.23 pm/V (CdSe{sub 0.5}Te{sub 0.5}), 32.25 pm/V (CdSe{sub 0.25}Te{sub 0.75}), and 37.70 pm/V (CdTe) for the cubic structure and from 12.65 pm/V (CdSe) to 21.11 pm/V (CdSe{sub 0.75}Te{sub 0.25}) in the wurtzite structure. We find a nonlinear relationship between the absorption/emission energies and composition, and a significant enhancement of the electronic properties as a function of tellurium concentration. This variation will help in

International conference on spin observables of nuclear probes: Summary talk

International Nuclear Information System (INIS)

Garvey, G.T.

1988-01-01

A selected summary of the presentation and discussions at the 4th Telluride Conference is presented. The summary deals mainly with the effects of nuclear spin and isospin on the interaction between nucleons and their consequences in nuclear structure. 11 figs

The system Ni–Sb–Te at 400°C

Czech Academy of Sciences Publication Activity Database

Laufek, F.; Drábek, M.; Skála, Roman

2010-01-01

Roč. 48, č. 5 (2010), s. 1069-1079 ISSN 0008-4476 Institutional research plan: CEZ:AV0Z30130516 Keywords : phase relations * vavřínite * system Ni–Sb–Te * tellurides Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.289, year: 2010

Synthesis of Novel E-2-Chlorovinyltellurium Compounds Based on the Stereospecific Anti-addition of Tellurium Tetrachloride to Acetylene

Directory of Open Access Journals (Sweden)

Svetlana V. Amosova

2012-05-01

Full Text Available The reaction of tellurium tetrachloride with acetylene proceeds in a stereospecific anti-addition manner to afford the novel products E-2-chlorovinyltellurium trichloride and E,E-bis(2-chlorovinyltellurium dichloride. Reaction conditions for the selective preparation of each of these products were found. The latter was obtained in 90% yield in CHCl₃ under a pressure of acetylene of 10–15 atm, whereas the former product was formed in up to 72% yield in CCl₄ under a pressure of acetylene of 1–3 atm. Synthesis of the previously unknown E,E-bis(2-chlorovinyl telluride, E,E-bis(2-chlorovinyl ditelluride, E-2-chlorovinyl 1,2,2-trichloroethyl telluride and E,E-bis(2-chlorovinyl-tellurium dibromide is described.

Ab initio investigation of the structural and electronic properties of amorphous HgTe

International Nuclear Information System (INIS)

Zhao, Huxian; Chen, Xiaoshuang; Shu, Haibo; Lu, Wei; Lu, Jianping

2014-01-01

We present the structure and electronic properties of amorphous mercury telluride obtained from first-principle calculations. The initial configuration of amorphous mercury telluride is created by computation alchemy. According to different exchange–correlation functions in our calculations, we establish two 256-atom models. The topology of both models is analyzed in terms of radial and bond angle distributions. It is found that both the Te and the Hg atoms tend to be fourfold, but with a wrong bond rate of about 10%. The fraction of threefold and fivefold atoms also shows that there are a significant number of dangling and floating bonds in our models. The electronic properties are also obtained. It is indicated that there is a bandgap in amorphous HgTe, in contrast to the zero bandgap for crystalline HgTe. The structures of the band tail and defect states are also discussed. (paper)

Ab initio investigation of the structural and electronic properties of amorphous HgTe.

Science.gov (United States)

Zhao, Huxian; Chen, Xiaoshuang; Lu, Jianping; Shu, Haibo; Lu, Wei

2014-01-29

We present the structure and electronic properties of amorphous mercury telluride obtained from first-principle calculations. The initial configuration of amorphous mercury telluride is created by computation alchemy. According to different exchange–correlation functions in our calculations, we establish two 256-atom models. The topology of both models is analyzed in terms of radial and bond angle distributions. It is found that both the Te and the Hg atoms tend to be fourfold, but with a wrong bond rate of about 10%. The fraction of threefold and fivefold atoms also shows that there are a significant number of dangling and floating bonds in our models. The electronic properties are also obtained. It is indicated that there is a bandgap in amorphous HgTe, in contrast to the zero bandgap for crystalline HgTe. The structures of the band tail and defect states are also discussed.

The performance of a combined solar photovoltaic (PV) and thermoelectric generator (TEG) system

DEFF Research Database (Denmark)

Bjørk, Rasmus; Nielsen, Kaspar Kirstein

2015-01-01

The performance of a combined solar photovoltaic (PV) and thermoelectric generator (TEG) system is examined using an analytical model for four different types of commercial PVs and a commercial bismuth telluride TEG. The TEG is applied directly on the back of the PV, so that the two devices have...... the same temperature. The PVs considered are crystalline Si (c-Si), amorphous Si (a-Si), copper indium gallium (di) selenide (CIGS) and cadmium telluride (CdTe) cells. The degradation of PV performance with temperature is shown to dominate the increase in power produced by the TEG, due to the low...... efficiency of the TEG. For c-Si, CIGS and CdTe PV cells the combined system produces a lower power and has a lower efficiency than the PV alone, whereas for an a-Si cell the total system performance may be slightly increased by the TEG....

Structural, optical, photoluminescence, dielectric and electrical ...

Indian Academy of Sciences (India)

The optical band gap of thin films was found to allow direct tran- sition with energy ... Cadmium telluride (CdTe) is an important group II–VI semi- ... Extensive research was done in the last two decades on CdTe ... 3.1 X-ray diffraction analysis.

Microbolometer spectrometer: applications and technology

NARCIS (Netherlands)

Leijtens, J.A.P.; Court, A.J.; Hoegee, J.

2004-01-01

Current Thermal Infra Red (7.14μm) multispectral imager instruments use cryogenically cooled Mercury Cadmium Telluride (MCT or HgCdTe) detectors. Now due to the increased performance of uncooled microbolometer arrays, the next generation of instruments can be designed without cryogenic cooling. TNO

Microbolometer spectrometer opens hoist of new applications

NARCIS (Netherlands)

Leijtens, J.A.P.; Smorenburg, C.; Escudero, I.; Boslooper, E.C.; Visser, H.; Helden, W.A. van; Breussin, F.N.

2004-01-01

Current Thermal infra red ( 7..14μm) multispectral imager instruments use cryogenically cooled Mercury Cadmium Telluride (MCT or HgCdTe) detectors. This causes the instruments to be bulky, power hungry and expensive. For systems that have medium NETD (Noise Equivalent Temperature Difference)

Spectrum-averaged cross-section measurement of /sup 103/Rh(n,n)/sup 103m/Rh in the /sup 252/Cf fission neutron spectrum

International Nuclear Information System (INIS)

Lamaze, G.P.; Schima, F.J.; Eisenhauer, C.M.; Spiegel, V.

1988-01-01

Because of the similarity in energy dependence of the /sup 103/Rh(n,n') differential cross section to the kerma muscle response function for neutrons, rhodium may be useful as a neutron kerma monitor. In support of its use as a neutron monitor, the spectrum-averaged cross section σ-bar has been measured for a /sup 252/Cf fission neutron spectrum. Pairs of thin rhodium samples were irradiated on opposite sides of a thinly encapsulated /sup 252/Cf neutron source. The neutron emission rate of the /sup 252/Cf source was determined by the manganous sulfate (MnSO/sub 4/) bath technique. In this method, the californium source emission rate is determined by comparison to the known emission rate of NBS-I, a standard radium-beryllium neutron source. The neutron fluence incident on the rhodium samples is determined from the californium source strength, average sample-to-source distance, and the duration of the irradiation. Corrections are made for neutron scattering saturation of activity, and attenuation of the X rays by the sample during counting. The X rays were detected with an intrinsic germanium detector designed specifically for low-energy X-ray detection. The activity was not determined by absolute counting so that the final results depend on the value of P/sub Κx/, to total Κ X-ray emission probability. The results of five separate irradiations yield a value of σ-bar . P/sub Κx/ = 62.3 +- 1.9 mb. Using the most recently published value of P/sub Κx/ gives a value of σ-bar = 739 +- 22 mb. A discussion of systematic uncertainties is given

Use of californium-252 sources in Hungary for teaching and research

International Nuclear Information System (INIS)

Csikai, J.

1976-01-01

An activation facility was designed to accommodate up to 50 mg of 252 Cf; it contains at present a 500 μg source. The absolute values of thermal, epithermal and fast neutron fluxes were determined by the foil activation method using In, Dy, Au, Al and Fe detectors. Cross-sections averaged for unmoderated 252 Cf neutrons were determined for 22 different reactions for elements with atomic weights lying between A=27 and 204. The sensitivity for determination of Al, Ti, Cu, As, Sr, Mo, In, Cd, Ba, Au, Hg and Pb was calculated for NaI(Tl) and Ge(Li) detectors. Average (n,2n) cross-sections for 252 Cf spectrum were calculated for 49 nuclei lying between A=14 and 204. Angular distributions and cross-sections for the fragments from 252 Cf neutron-induced fission of 232 Th and 238 U were measured. Titanium in bauxite and manganese in aluminium alloys were determined with a 252 Cf source. The applicability of solid-state track detectors for neutron dosimetry, radiography and for the determination of fuel burn-up were investigated using 252 Cf neutron and fragment sources. Characteristics of a jumping spark counter for counting fission fragments were studied with 252 Cf sources. (author)

Review of microscopic integral cross section data in fundamental reactor dosimetry benchmark neutron fields

International Nuclear Information System (INIS)

Fabry, A.; McElroy, W.N.; Kellogg, L.S.; Lippincott, E.P.; Grundl, J.A.; Gilliam, D.M.; Hansen, G.E.

1976-01-01

This paper is intended to review and critically discuss microscopic integral cross section measurement and calculation data for fundamental reactor dosimetry benchmark neutron fields. Specifically the review covers the following fundamental benchmarks: the spontaneous californium-252 fission neutron spectrum standard field; the thermal-neutron induced uranium-235 fission neutron spectrum standard field; the (secondary) intermediate-energy standard neutron field at the center of the Mol-ΣΣ, NISUS, and ITN-ΣΣ facilities; the reference neutron field at the center of the Coupled Fast Reactor Measurement Facility; the reference neutron field at the center of the 10% enriched uranium metal, cylindrical, fast critical; the (primary) Intermediate-Energy Standard Neutron Field

Development of a transportable neutron radiography system for non-destructive tests application

International Nuclear Information System (INIS)

Silva, Ademir X. da; Crispim, Verginia R.

1999-01-01

This paper presents a study of a transportable neutron radiography system utilizing californium-252. Studies about moderation, collimation and shielding are showed. A Monte Carlo Code, MCNP3b, has been used to obtain a maximum and more homogeneous thermal neutron flux in the collimator outlet next to the image plain, and an adequate radiation shielding to attend radiological protection rules. With the presented collimator, it was possible to obtain for the thermal neutron flux, at the collimator outlet and next to the image plain, a L/D ratio 7,5, for neutron flux up to 6 X 10 -6 cm -2 .s -1 per neutron source. (author)

Neutron crosstalk between liquid scintillators

Energy Technology Data Exchange (ETDEWEB)

Verbeke, J.M., E-mail: verbeke2@llnl.gov; Prasad, M.K., E-mail: prasad1@llnl.gov; Snyderman, N.J., E-mail: snyderman1@llnl.gov

2015-09-11

A method is proposed to quantify the fractions of neutrons scattering between liquid scintillators. Using a spontaneous fission source, this method can be utilized to quickly characterize an array of liquid scintillators in terms of crosstalk. The point model theory due to Feynman is corrected to account for these multiple scatterings. Using spectral information measured by the liquid scintillators, fractions of multiple scattering can be estimated, and mass reconstruction of fissile materials under investigation can be improved. Monte Carlo simulations of mono-energetic neutron sources were performed to estimate neutron crosstalk. A californium source in an array of liquid scintillators was modeled to illustrate the improvement of the mass reconstruction.

Neutron crosstalk between liquid scintillators

International Nuclear Information System (INIS)

Verbeke, J.M.; Prasad, M.K.; Snyderman, N.J.

2015-01-01

A method is proposed to quantify the fractions of neutrons scattering between liquid scintillators. Using a spontaneous fission source, this method can be utilized to quickly characterize an array of liquid scintillators in terms of crosstalk. The point model theory due to Feynman is corrected to account for these multiple scatterings. Using spectral information measured by the liquid scintillators, fractions of multiple scattering can be estimated, and mass reconstruction of fissile materials under investigation can be improved. Monte Carlo simulations of mono-energetic neutron sources were performed to estimate neutron crosstalk. A californium source in an array of liquid scintillators was modeled to illustrate the improvement of the mass reconstruction

Radiological safety considerations in the design and operation of the ORNL Transuranium Research Laboratory (TRL)

International Nuclear Information System (INIS)

Haynes, C.E.

1976-01-01

The Transuranium Research Laboratory (TRL) is the central facility at Oak Ridge National Laboratory (ORNL) for chemical and physical research involving transuranium elements. Transuranium Research Laboratory investigations are about equally divided between studies of inorganic and structural chemistry of the heavy elements and nuclear structure and properties of their isotopes. Elements studied include neptunium, plutonium, americium, curium, berkelium, californium, and einsteinium, each in microgram-to-gram quantities depending upon availability and experimental requirements. This paper describes an eight-step safety procedure followed in planning and approving individual research projects. This procedure should provide an optimum margin of safety and should permit the accomplishment of successful research

Determination of alpha activity and fissile mass content in solid waste by systems using neutron interrogation

International Nuclear Information System (INIS)

Romeyer Dherbey, J.; Lacruche, G.; Berne, R.; Auge, J.; Martin Deidier, L.; Butez, M.

1990-01-01

The Quantitative control (determination of heavy nuclides and alpha activity) of alpha radioactive wastes is necessary, particularly to determine if the waste is in accordance with the surface storage limits. In order to reduce the uncertainty on the alpha activity resulting from unknown isotopic composition, inhomogeneity of heavy nuclides in the matrix, combination of several methods is necessary. In the paper we present the Cadarache development work in the NDA of solid waste using the Californium shuffler, 14 Mev neutron generator, and also passive techniques such as neutron emission measurement and gamma spectrometry. Experimental systems combining active and passive methods are presented (COSAC, BANCO, DANAIDE, PROMETHEE)

Beam test of a grid-less multi-harmonic buncher

International Nuclear Information System (INIS)

Ostroumov, P.N.; Aseev, V.N.; Barcikowski, A.; Clifft, B.; Pardo, R.; Sharamentov, S.I.; Sengupta, M.

2008-01-01

The Argonne Tandem Linear Accelerator System (ATLAS) is the first superconducting heavy-ion linac in the world. Currently ATLAS is being upgraded with the Californium Rare Ion Breeder Upgrade (CARIBU). The latter is a funded project to expand the range of shortlived, neutron-rich rare isotope beams available for nuclear physics research at ATLAS. To avoid beam losses associated with the existing gridded multi-harmonic buncher (MHB), we have developed and built a grid-less four-harmonic buncher with fundamental frequency of 12.125 MHz. In this paper, we report the results of the MHB commissioning and ATLAS beam performance with the new buncher.

Composition containing transuranic elements for use in the homeopathic treatment of aids

International Nuclear Information System (INIS)

Lustig, D.

1996-01-01

A homeopathic remedy consisting of a composition containing one or more transuranic elements, particularly plutonium, for preventing and treating acquired immunodeficiency syndrome (AIDS) in humans, as well as seropositivity for human immunodeficiency virus (HIV). Said composition is characterized in that it uses any chemical or isotopic form of one or more transuranic elements (neptunium, plutonium, americium, curium, berkelium, californium or einsteinium), particularly plutonium, said form being diluted and dynamized according to conventional homeopathic methods, particularly the so-called Hahnemann and Korsakov methods, and provided preferably but not exclusively in the form of lactose and/or saccharose globules or granules impregnated with the active principle of said composition. (author)

PROCEEDINGS OF THE SYMPOSIUM COMMEMORATING THE 25th ANNIVERSARY OF ELEMENTS 97 and 98 HELD ON JAN. 20, 1975

Energy Technology Data Exchange (ETDEWEB)

Seaborg, Glenn T.; Street Jr., Kenneth; Thompson, Stanley G.; Ghiorso, Albert

1976-07-01

This volume includes the talks given on January 20, 1975, at a symposium in Berkeley on the occasion of the celebration of the 25th anniversary of the discovery of berkelium and californium. Talks were given at this symposium by the four people involved in the discovery of these elements and by a number of people who have made significant contributions in the intervening years to the investigation of their nuclear and chemical properties. The papers are being published here, without editing, in the form in which they were submitted by the authors in the months following the anniversary symposium, and they reflect rather faithfully the remarks made on that occasion.

TOWARD AN IMPROVED UNDERSTANDING OF STRUCTURE AND MAGNETISM IN NEPTUNIUM AND PLUTONIUM PHOSPHONATES AND SULFONATES

Energy Technology Data Exchange (ETDEWEB)

Albrecht-Schmitt, Thomas

2012-03-01

This grant supported the exploratory synthesis of new actinide materials with all of the actinides from thorium to californium with the exceptions of protactinium and berkelium. We developed detailed structure-property relationships that allowed for the identification of novel materials with selective ion-exchange, selective oxidation, and long-range magnetic ordering. We found novel bonding motifs and identified periodic trends across the actinide series. We identified structural building units that would lead to desired structural features and novel topologies. We also characterized many different spectroscopic trends across the actinide series. The grant support the preparation of approximately 1200 new compounds all of which were structurally characterized.

Triton and alpha-particle contribution from LiF converter for neutron dosimeter

CERN Document Server

Camacho, M E; Balcazar, M

1999-01-01

A personnel neutron dosimeter prototype based on chemical and electrochemical etched CR-39 detector, combined with LiF converter, has been calibrated using an ICRP-like phantom, under a heavy-water moderated Californium source neutron spectra; A conversion factor of 1.052+-126 spots cm sup - sup 2 mSv sup - sup 1 was obtained. The sealing properties of the detector holder showed a ten-fold reduction in radon background when it was tested in a high radon atmosphere. A convenient mechanical shock resistance was achieved in LiF converters by sintering to 11 tons pressure LiF powder at 650 deg. C, during one hour.

Characterization of nanocrystalline cadmium telluride thin films ...

Indian Academy of Sciences (India)

Unknown

tion method, successive ionic layer adsorption and reaction (SILAR), are described. For deposition of CdTe thin films ... By conducting several trials optimization of the adsorption, reaction and rinsing time duration for CdTe thin film .... The electrical resistivity of CdTe films was studied in air. Figure 3 shows the variation of log ...

Cadium-Zinc-Telluride (CZT) Gamma Ray Spectrometry

International Nuclear Information System (INIS)

William Quam

2001-01-01

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

Tunable Terahertz Metamaterials with Germanium Telluride Components

Science.gov (United States)

2016-03-24

successful inspection of the pattern under the microscope, the sample is placed under the deep- UV flood exposure lamp for 200 seconds, and then developed...state digital memory applications, and have led the ubiquity of devices such as CDs and DVDs. The general temperature profiles required to switch...manufacturing methods has led to a recent rise in its popularity [125]. There are several types of additive manufacturing processes. One of the first to be

Growth and characterization of bismuth telluride nanowires

Energy Technology Data Exchange (ETDEWEB)

Picht, Oliver

2010-05-26

Polycrystalline Bi{sub 2}Te{sub 3} nanowires are electrochemically grown in ion track-etched polycarbonate membranes. Potentiostatic growth is demonstrated in templates of various thicknesses ranging from 10 to 100 {mu}m. The smallest observed nanowire diameters are 20 nm in thin membranes and approx. 140-180 nm in thicker membranes. The influence of the various deposition parameters on the nanowire growth rate is presented. Slower growth rates are attained by selective change of deposition potentials and lower temperatures. Nanowires synthesized at slower growth rates have shown to possess a higher degree of crystalline order and smoother surface contours. With respect to structural properties, X-ray diffraction and transmission electron microscopy verified the growth of Bi{sub 2}Te{sub 3} and evidenced the stability of specific properties, e.g. grain size or preferential orientation, with regard to variations in the deposition conditions. The interdependency of the fabrication parameters, i.e. temperature, deposition potential and nanochannel diameters, is demonstrated for wires grown in 30 {mu}m thick membranes. It is visible from diffraction analysis that texture is tunable by the growth conditions but depends also on the size of the nanochannels in the template. Both (015) and (110) reflexes are observed for the nanowire arrays. Energy dispersive X-ray analysis further points out that variation of nanochannel size could lead to a change in elemental composition of the nanowires. (orig.)

High-temperature thermoelectric behavior of lead telluride

Indian Academy of Sciences (India)

Usefulness of a material in thermoelectric devices is temperature specific. The central problem in thermoelectric material research is the selection of materials with high figure-of-merit in the given temperature range of operation. It is of considerable interest to know the utility range of the material, which is decided by the ...

XAFS studies of ytterbium doped lead-telluride

International Nuclear Information System (INIS)

Radisavljevic, I.; Novakovic, N.; Romcevic, N.; Manasijevic, M.; Mahnke, H.-E.; Ivanovic, N.

2010-01-01

X-ray Absorption Fine Structure (XAFS) measurements were performed on uniformly doped PbTe:Yb (1.3 at.%) at all elemental absorption edges and the analysis of the results has provided precise information on the local structure around each atom. From the near edge part of the absorption spectra it was determined that Yb is in the mixed valent state, which is predominantly divalent with a small trivalent contribution. The analysis of the high energy region of the absorption spectra revealed that Yb incorporation causes deformation of the host PbTe lattice, manifested through extension of all the nearest-, and next-nearest neighbour distances.

Neutron activation analysis of manganese-mercury telluride

International Nuclear Information System (INIS)

Sadykov, I. I.

2003-01-01

The triple semiconductor compound Mn x Hg 1-x Te is a worthwhile material for the development of infra-red detectors. It's properties, as well as other semiconductors ones depend on impurity elements content. So, analytical Purity control of Mn x Hg 1-x Te is required. Some procedures of the neutron activation analysis of Te[1], Hg [2] and that of their compounds (Cd x Hg 1-x Te [3], for instance) have been developed recently. However, no papers on the NAA of Mn x Hg 1-x Te have been found. This paper describes the procedure of the NAA of Mn x Hg 1-x Te based on anion-exchange chromatographic separation of impurity and matrix elements. Experimental The following reagents were used: commerciality available strongly based anion-exchange resin AW-17 (50-100 meash), hydrochloride hydrasine of analytical grade, solutions of HCl and HNO 3 prepared from concentrated acids of reagent grade. Separation processes were studied by radioactive tracers. The gamma-activity was measured on a HPGe detector GC1518 (efficiency 15 %, resolution 1,7 keV at 1332,5 keV line of 6 0C o) using DSA-1000 digital multichannel analyzer (Canberra, USA). Radioactive tracers were produced by irradiation of metals, salts or oxides of corresponding elements in WWR-SM water-water nuclear reactor. Irradiation of Mn x Hg 1-x Te samples and standards was carried out in a channel of WWR-SM reactor with a neutron flux density of 1.10 14 cm 2 .s -1 for 10 h. Solutions of manganese and mercury were prepared by dissolving their oxides in concentric hydrochloric acid. Solutions of tellurium were prepared by dissolving metallic tellurium in HCl:HNO 3 (3:1) mixture. Solution obtained was evaporated to dryness, the reside was dissolved in conc. HCl. To reduce tellurium to Te(IV) 1-2 mg of hydrazine were dissolved in solution at slight heating. Then, distilled water was added in a required quantities to get a desired concentration of HCl. The chromatographic behaviour of matrix and impurity elements was studied using chromatographic columns, filled with AW-17 resin (columns' i. d. 1.2 cm , resin layer height 10 cm, mobil phase volume 5.5 cm 3 ), prepared according to recommendations of [4]. 10 ml of the solution containing 61 mg of Te, 86 mg of Hg and 2.6 mg of Mn (That corresponds to 150 mg of Mn x Hg 1-x Te) and radioactive tracers were placed into chromatographic column and then impurities were eluted with 4 M HCl. Eluation rate was about 0.5-0.6 ml/min. Eluated was collected in a portions of 1 ml, followed by measuring it's gamma-activity. To study the distribution of matrix radionuclides along the column their activity was measured using a lead collimator

Growth and characterization of bismuth telluride nanowires

International Nuclear Information System (INIS)

Picht, Oliver

2010-01-01

Polycrystalline Bi 2 Te 3 nanowires are electrochemically grown in ion track-etched polycarbonate membranes. Potentiostatic growth is demonstrated in templates of various thicknesses ranging from 10 to 100 μm. The smallest observed nanowire diameters are 20 nm in thin membranes and approx. 140-180 nm in thicker membranes. The influence of the various deposition parameters on the nanowire growth rate is presented. Slower growth rates are attained by selective change of deposition potentials and lower temperatures. Nanowires synthesized at slower growth rates have shown to possess a higher degree of crystalline order and smoother surface contours. With respect to structural properties, X-ray diffraction and transmission electron microscopy verified the growth of Bi 2 Te 3 and evidenced the stability of specific properties, e.g. grain size or preferential orientation, with regard to variations in the deposition conditions. The interdependency of the fabrication parameters, i.e. temperature, deposition potential and nanochannel diameters, is demonstrated for wires grown in 30 μm thick membranes. It is visible from diffraction analysis that texture is tunable by the growth conditions but depends also on the size of the nanochannels in the template. Both (015) and (110) reflexes are observed for the nanowire arrays. Energy dispersive X-ray analysis further points out that variation of nanochannel size could lead to a change in elemental composition of the nanowires. (orig.)

Bulletin of Materials Science | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Bulletin of Materials Science. Sandeep Arya. Articles written in Bulletin of Materials Science. Volume 36 Issue 4 August 2013 pp 535-539. Synthesis of copper telluride nanowires using template-based electrodeposition method as chemical sensor · Sandeep Arya Saleem Khan Suresh Kumar Rajnikant ...

Applications of CdTe to nuclear medicine. Final report

International Nuclear Information System (INIS)

Entine, G.

1985-01-01

Uses of cadmium telluride (CdTe) nuclear detectors in medicine are briefly described. They include surgical probes and a system for measuring cerebral blood flow in the intensive care unit. Other uses include nuclear dentistry, x-ray exposure control, cardiology, diabetes, and the testing of new pharmaceuticals

Thin-Film Material Science and Processing | Materials Science | NREL

Science.gov (United States)

Thin-Film Material Science and Processing Thin-Film Material Science and Processing Photo of a , a prime example of this research is thin-film photovoltaics (PV). Thin films are important because cadmium telluride thin film, showing from top to bottom: glass, transparent conducting oxide (thin layer

Teresa Barnes, Ph.D. | NREL

Science.gov (United States)

graduate student. She came to NREL as a postdoctoral researcher to continue working on transparent conducting oxides and began working on carbon nanotube and metal nanowire transparent contacts. She is currently a senior scientist at NREL working on cadmium telluride (CdTe) solar cells. Her research interests

The crystal structure of Pd.sub.3./sub.HgTe.sub.3./sub., the synthetic analogue of temagamite

Czech Academy of Sciences Publication Activity Database

Laufek, F.; Vymazalová, A.; Drábek, M.; Dušek, Michal; Navrátil, Jiří; Černošková, E.

2016-01-01

Roč. 28, č. 4 (2016), s. 825-834 ISSN 0935-1221 Institutional support: RVO:68378271 ; RVO:61389013 Keywords : temagamite * crystal structure * crystal-structure solution * Pd-Hg telluride Subject RIV: BM - Solid Matter Physics ; Magnetism; CD - Macromolecular Chemistry (UMCH-V) Impact factor: 1.362, year: 2016

Optimization of the Mechanical and Electrical Performance of a Thermoelectric Module

DEFF Research Database (Denmark)

Sarhadi, Ali; Bjørk, Rasmus; Pryds, Nini

2015-01-01

Finite element (FE) simulation of a thermoelectric (TE) module was conducted to optimize its geometrical dimensions in terms of mechanical reliability and performance. The TE module consisted of bismuth telluride, nand p-type legs. The geometrical dimensions of the module, i.e. leg length and leg...

Saleem Khan

Indian Academy of Sciences (India)

Home; Journals; Bulletin of Materials Science. Saleem Khan. Articles written in Bulletin of Materials Science. Volume 36 Issue 4 August 2013 pp 535-539. Synthesis of copper telluride nanowires using template-based electrodeposition method as chemical sensor · Sandeep Arya Saleem Khan Suresh Kumar Rajnikant ...

The topological Anderson insulator phase in the Kane-Mele model

Science.gov (United States)

Orth, Christoph P.; Sekera, Tibor; Bruder, Christoph; Schmidt, Thomas L.

2016-04-01

It has been proposed that adding disorder to a topologically trivial mercury telluride/cadmium telluride (HgTe/CdTe) quantum well can induce a transition to a topologically nontrivial state. The resulting state was termed topological Anderson insulator and was found in computer simulations of the Bernevig-Hughes-Zhang model. Here, we show that the topological Anderson insulator is a more universal phenomenon and also appears in the Kane-Mele model of topological insulators on a honeycomb lattice. We numerically investigate the interplay of the relevant parameters, and establish the parameter range in which the topological Anderson insulator exists. A staggered sublattice potential turns out to be a necessary condition for the transition to the topological Anderson insulator. For weak enough disorder, a calculation based on the lowest-order Born approximation reproduces quantitatively the numerical data. Our results thus considerably increase the number of candidate materials for the topological Anderson insulator phase.

/sup 123m/Te-labeled biochemicals and method of preparation

International Nuclear Information System (INIS)

Knapp, F.

1980-01-01

A process for preparing a /sup 123m/Te-labeled organic compound of the formula R-/sup 123m/Te-CH 2 -R', R being alkyl, substituted alkyl, aryl or substituted aryl and R' being a steroidal side chain, alkyl amino acid or amino acid group, said process comprising the steps of: (A) reaching a /sup 123m/Te-symmetric diorgano ditelluride, R 2 /sup 123m/Te 2 , R being alkyl, substituted alkyl, aryl or substituted aryl, with a hydride reducing agent and a source of alkali metal ions to form an alkali metal organo telluride M-/sup 123m/Te-R; (B) reacting said alkali metal organo telluride with a primary halogenated organic compound R/sub a/'-X, R/sub a/' being a 17 alkyl steroid group having 1-4 carbon atoms in said alkyl group, an alkyl amino acid group, or a group hydrolyzable to an alkyl amino acid group

Consideration of relativistic effects in band structure calculations based on the empirical tight-binding method

International Nuclear Information System (INIS)

Hanke, M.; Hennig, D.; Kaschte, A.; Koeppen, M.

1988-01-01

The energy band structure of cadmium telluride and mercury telluride materials is investigated by means of the tight-binding (TB) method considering relativistic effects and the spin-orbit interaction. Taking into account relativistic effects in the method is rather simple though the size of the Hamilton matrix doubles. Such considerations are necessary for the interesting small-interstice semiconductors, and the experimental results are reflected correctly in the band structures. The transformation behaviour of the eigenvectors within the Brillouin zone gets more complicated, but is, nevertheless, theoretically controllable. If, however, the matrix elements of the Green operator are to be calculated, one has to use formula manipulation programmes in particular for non-diagonal elements. For defect calculations by the Koster-Slater theory of scattering it is necessary to know these matrix elements. Knowledge of the transformation behaviour of eigenfunctions saves frequent diagonalization of the Hamilton matrix and thus permits a numerical solution of the problem. Corresponding results for the sp 3 basis are available

CdZnTe and CdTe materials for X-ray and gamma ray radiation detector applications

International Nuclear Information System (INIS)

Szeles, Csaba

2004-01-01

Good detection efficiency and high energy-resolution make Cadmium Zinc Telluride (CdZnTe) and Cadmium Telluride (CdTe) detectors attractive in many room temperature X-ray and gamma-ray detection applications such as medical and industrial imaging, industrial gauging and non-destructive testing, security and monitoring, nuclear safeguards and non-proliferation, and astrophysics. Advancement of the crystal growth and device fabrication technologies and the reduction of bulk, interface and surface defects in the devices are crucial for the widespread practical deployment of Cd 1-x Zn x Te-based detector technology. Here we review the effects of bulk, interface and surface defects on charge transport, charge transport uniformity and device performance and the progress in the crystal growth and device fabrication technologies aiming at reducing the concentration of harmful defects and improving Cd 1-x Zn x Te detector performance. (copyright 2004 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Analysis of MCNP simulated gamma spectra of CdTe detectors for boron neutron capture therapy.

Science.gov (United States)

Winkler, Alexander; Koivunoro, Hanna; Savolainen, Sauli

2017-06-01

The next step in the boron neutron capture therapy (BNCT) is the real time imaging of the boron concentration in healthy and tumor tissue. Monte Carlo simulations are employed to predict the detector response required to realize single-photon emission computed tomography in BNCT, but have failed to correctly resemble measured data for cadmium telluride detectors. In this study we have tested the gamma production cross-section data tables of commonly used libraries in the Monte Carlo code MCNP in comparison to measurements. The cross section data table TENDL-2008-ACE is reproducing measured data best, whilst the commonly used ENDL92 and other studied libraries do not include correct tables for the gamma production from the cadmium neutron capture reaction that is occurring inside the detector. Furthermore, we have discussed the size of the annihilation peaks of spectra obtained by cadmium telluride and germanium detectors. Copyright © 2017 Elsevier Ltd. All rights reserved.

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

On 28th September 2015, India launched its first astronomical space observatory AstroSat, successfully. AstroSat carried five astronomy payloads, namely, (i) Cadmium Zinc Telluride Imager (CZTI), (ii) Large Area X-ray Proportional Counter (LAXPC), (iii) Soft X-ray Telescope (SXT), (iv) Ultra Violet Imaging Telescope (UVIT) ...

KFeSbTe3: A quaternary chalcogenide aerogel for preferential adsorption of polarizable hydrocarbons and gases

KAUST Repository

Ahmed, Ejaz; Rothenberger, Alexander

2015-01-01

The first telluride-based quaternary aerogel KFeSbTe3 is synthesized by a sol-gel metathesis reaction between Fe(OAc)2 and K3SbTe3 in dimethyl formamide. The aerogel has an exceptionally large surface area 652 m2 g-1 which is amongst the highest

Bulletin of Materials Science | News

Indian Academy of Sciences (India)

Effect of heat treatment on tensile behaviour of Ti–6Al–5Zr–0.5Mo–0.25Si alloy ... Microstructural characterization in diffusion bonded TiC–Al2O3/Cr18–Ni8 joint with ... Characterization of nanocrystalline cadmium telluride thin films grown by ...

Minimizing Patient-Specific Tracer Dose in Myocardial Perfusion Imaging Using CZT SPECT

NARCIS (Netherlands)

van Dijk, Joris David; Jager, Pieter L.; Ottervanger, Jan Paul; Slump, Cornelis H.; de Boer, Jaep; Oostdijk, Adrianus H.J.; van Dalen, Jorn A.

Myocardial perfusion imaging (MPI) with SPECT is widely adopted in clinical practice but is associated with a relatively high radiation dose. The aim of this study was to determine the minimum product of tracer dose and scan time that will maintain diagnostic value for cadmium zinc telluride (CZT)

Advanced Processing of CdTe- and CuInxGa1-xSe2-Based Solar Cells: Final Report: 18 April 1995 - 31 May 1998

International Nuclear Information System (INIS)

Jayapalan, A.; Tetali, B.; Ferekides, C.S.; Marinskiy, D.; Morel, D.L.; Lin, H.; Sankaranarayanan, H.; Bhatt, R.; Narayanaswamy, R.; Prabhakaran, R.; Marinskaya, S.; Zafar, S.

1999-01-01

This report summarizes work performed by the University of South Florida Department of Electrical Engineering under this subcontract. The Cadmium telluride(CdTe) portion of this project deals with the development of high-efficiency thin-filmed CdTe solar cells using fabrication techniques that are suitable for manufacturing environments

Results of metallographical diagnostic examination of Navy half-watt thermoelectric converters degraded by accelerated tests

International Nuclear Information System (INIS)

Rosell, F.E. Jr.; Rouklove, P.G.

1977-01-01

To verify the 15-year reliability of the Navy half-watt radioisotope thermoelectric generator (RTG), bismuth--telluride thermoelectric converters were submitted to testing at high temperatures which accelerated the degradation and caused failure of the converters. Metallographic diagnostic examination of failed units verified failure mechanisms. Results of diagnostic examinations are presented

Self-Powered Functional Device Using On-Chip Power Generation

KAUST Repository

Hussain, Muhammad Mustafa

2012-01-26

An apparatus, system, and method for a self-powered device using on-chip power generation. In some embodiments, the apparatus includes a substrate, a power generation module on the substrate, and a power storage module on the substrate. The power generation module may include a thermoelectric generator made of bismuth telluride.

Instrument for measuring metal-thermoelectric semiconductor contact resistence

International Nuclear Information System (INIS)

Lanxner, M.; Nechmadi, M.; Meiri, B.; Schildkraut, I.

1979-02-01

An instrument for measuring electrical, metal-thermoelectric semiconductor contact resistance is described. The expected errors of measurement are indicated. The operation of the instrument which is based on potential traversing perpendicularly to the contact plane is illustrated for the case of contacts of palladium and bismuth telluride-based thermoelectric material

Self-Powered Functional Device Using On-Chip Power Generation

KAUST Repository

Hussain, Muhammad Mustafa

2012-01-01

An apparatus, system, and method for a self-powered device using on-chip power generation. In some embodiments, the apparatus includes a substrate, a power generation module on the substrate, and a power storage module on the substrate. The power generation module may include a thermoelectric generator made of bismuth telluride.

The crystal structure of sopcheite, Ag.sub.4./sub.Pd.sub.3./sub.Te.sub.4./sub., from the Lukkulaisvaara intrusion, Karelia, Russia

Czech Academy of Sciences Publication Activity Database

Laufek, F.; Vymazalová, A.; Grokhovskaya, T.L.; Plášil, Jakub; Dušek, Michal; Orsoev, D.A.; Kozlov, V.V.

2017-01-01

Roč. 29, Jun (2017), s. 603-612 ISSN 0935-1221 Institutional support: RVO:68378271 Keywords : sopcheite * crystal structure * Ag4Pd3Te4 * platinum-group mineral * silver palladium telluride * X-ray diffraction data * Lukkulaisvaara intrusion Subject RIV: DB - Geology ; Mineralogy OBOR OECD: Geology Impact factor: 1.362, year: 2016

Study of reproducibility of measurements with the spectrometer of Bonner multispheres

International Nuclear Information System (INIS)

Azevedo, G.A.; Pereira, W.W.; Patrao, K.C.S.; Fonseca, E.S.

2013-01-01

This work aims to study the metrological behavior of the Bonner Multisphere Spectrometer (BMS) of the LN / LNMRI / IRD - Laboratorio Metrologia de Neutrons / Laboratorio Nacional de Metrologia e Radiacao Ionizante / Instituto de Radioprotecao e Dosimetria, for measurements in repeatability and reproducibility conditions. Initially, a simulation was done by applying the Monte Carlo method, using the MCNP code and respecting the ISO 8529-1 (2001), using the sources of Californium ( 252 Cf), Americium-Beryllium ( 241 AmBe) and californium in heavy water (Cf + D 2 O), all located at a distance of 100 cm from the neutron detector ( 6 Li (Eu) - crystal scintillator). In this program, the counting of neutrons that are captured by the detector was made. The source is located in the center of a sphere of radius 300 cm. Analyzes the impact of these neutrons in a point of the sphere wall, which in this case acted as a neutron detector and from there, it is estimated the number of neutrons that collide in the whole sphere. The purpose is to obtain the neutron count for different energy bands in a solid field of neutrons, since they have a spectrum ranging from a low to a high energy that can also vary within a particular environment. Wishes to obtain new fields with different sources and moderators materials to be used as new reference fields. Measurements are being conducted for these fields, with the aim of analyzing the variability conditions of the measurement (repeatability and reproducibility) in LEN - Laboratorio de Espectrometria de Neutrons of the LN/LMNRI/IRD. Thus, the spectrometer will be used to improve both the knowledge of the spectrum as the standard of neutrons of the lab, proving that a spectrometry is essential for correct measurement

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. Essy Samuel. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 2 June 2017 pp 31 Review Article. The Cadmium Zinc Telluride Imager on AstroSat · V. Bhalerao D. Bhattacharya A. Vibhute P. Pawar A. R. Rao M. K. Hingar Rakesh Khanna ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. N. Vagshette. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 2 June 2017 pp 31 Review Article. The Cadmium Zinc Telluride Imager on AstroSat · V. Bhalerao D. Bhattacharya A. Vibhute P. Pawar A. R. Rao M. K. Hingar Rakesh Khanna ...

Manhattan Project Technical Series: The Chemistry of Uranium (I)

International Nuclear Information System (INIS)

Rabinowitch, E. I.; Katz, J. J.

1947-01-01

This constitutes Chapters 11 through 16, inclusive, of the Survey Volume on Uranium Chemistry prepared for the Manhattan Project Technical Series. Chapters are titled: Uranium Oxides, Sulfides, Selenides, and Tellurides; The Non-Volatile Fluorides of Uranium; Uranium Hexafluoride; Uranium-Chlorine Compounds; Bromides, Iodides, and Pseudo-Halides of Uranium; and Oxyhalides of Uranium.

First ever full size CdTE luminescent down-shifting module

NARCIS (Netherlands)

Ross, D.; Alonso-Alvarez, D.; Fritsche, J.; Bauer, M.; Debije, M.G.; Fifield, R.M.; Richards, B.S.

2012-01-01

For the first time a luminescent down-shifting (LDS) layer has been applied to a full size PV module to improve its short-wavelength response. An average 4.3% relative increase in the short-circuit current density (JSC) was recorded for the Calyxo cadmium telluride (CdTe) modules after the best LDS

Optical band gap and Raman spectra in AxB0.2-x(TeO2)0.8 glasses

Czech Academy of Sciences Publication Activity Database

Ožďanová, J.; Tichá, H.; Tichý, Ladislav

2010-01-01

Roč. 12, č. 5 (2010), s. 1024-1029 ISSN 1454-4164 Institutional research plan: CEZ:AV0Z40500505 Keywords : telluride glasses * optical band gap * Raman scattering Subject RIV: CA - Inorganic Chemistry Impact factor: 0.412, year: 2010 http://joam.inoe.ro/index.php?option=magazine&op=view&idu=2453&catid=50

Manhattan Project Technical Series: The Chemistry of Uranium (I)

Energy Technology Data Exchange (ETDEWEB)

Rabinowitch, E. I. [Argonne National Lab. (ANL), Argonne, IL (United States); Katz, J. J. [Argonne National Lab. (ANL), Argonne, IL (United States)

1947-03-10

This constitutes Chapters 11 through 16, inclusive, of the Survey Volume on Uranium Chemistry prepared for the Manhattan Project Technical Series. Chapters are titled: Uranium Oxides, Sulfides, Selenides, and Tellurides; The Non-Volatile Fluorides of Uranium; Uranium Hexafluoride; Uranium-Chlorine Compounds; Bromides, Iodides, and Pseudo-Halides of Uranium; and Oxyhalides of Uranium.

Environmental assessment of the thermal neutron activation explosive detection system for concourse use at US airports

Energy Technology Data Exchange (ETDEWEB)

Jones, C.G.

1990-08-01

This document is an environmental assessment of a system designed to detect the presence of explosives in checked airline baggage or cargo. The system is meant to be installed at the concourse or lobby ticketing areas of US commercial airports and uses a sealed radioactive source of californium-252 to irradiate baggage items. The major impact of the use of this system arises from direct exposure of the public to scattered or leakage radiation from the source and to induced radioactivity in baggage items. Under normal operation and the most likely accident scenarios, the environmental impacts that would be created by the proposed licensing action would not be significant. 44 refs., 19 figs., 18 tabs.

Alternative irradiation system for efficiency manganese bath determination

Energy Technology Data Exchange (ETDEWEB)

Passos Leite, Sandro, E-mail: sandro@ird.gov.b [Programa de Engenharia Nuclear/COPPE, Universidade Federal do Rio de Janeiro, Ilha do Fundao, Caixa Postal 68509, 21945-970, Rio de Janeiro, RJ (Brazil); Wagner Pereira, Walsan, E-mail: walsan@ird.gov.b [Instituto de Radioprotecao e Dosimetria LNMRI/IRD/CNEN, Av. Salvador Allende, s/no, Recreio dos Bandeirantes, CEP: 22780-160, Rio de Janeiro (Brazil); Xavier da Silva, Ademir, E-mail: ademir@con.ufrj.b [Programa de Engenharia Nuclear/COPPE, Universidade Federal do Rio de Janeiro, Ilha do Fundao, Caixa Postal 68509, 21945-970, Rio de Janeiro, RJ (Brazil); Simoes da Fonseca, Evaldo, E-mail: evaldo@ird.gov.b [Instituto de Radioprotecao e Dosimetria LNMRI/IRD/CNEN, Av. Salvador Allende, s/no, Recreio dos Bandeirantes, CEP: 22780-160, Rio de Janeiro (Brazil); Souza Patrao, Karla Cristina de, E-mail: karla@ird.gov.b [Instituto de Radioprotecao e Dosimetria LNMRI/IRD/CNEN, Av. Salvador Allende, s/no, Recreio dos Bandeirantes, CEP: 22780-160, Rio de Janeiro (Brazil)

2010-12-15

An alternative irradiation system, which works with a radionuclide neutron source and manganese sulphate solution volume have been proposed for efficiency determination of a Manganese Bath System (MBS). This irradiation system was designed by simulation with MCNP5 code, considering a californium neutron source in several manganese sulphate volumes and different neutron reflectors. Although its solution specific activity are less than those in nuclear reactors, the simulation results have showed that the irradiation system proposed takes a manganese neutron capture increase up to 200 times when it compared to manganese neutron capture from a MBS whose diameter is about 100 cm. That becomes possible to use those samples for some of the absolute specific activity measuring methods.

Experimental survey of the potential energy surfaces associated with fission

International Nuclear Information System (INIS)

Britt, H.C.

1980-01-01

Progress in the experimental determination of the properties of the potential energy surface associated with fission is reviewed. The importance of nuclear symmetry effects on the calculation of fission widths is demonstrated. Evidence is presented for the fragmentation of the mass-asymmetric second barrier in the thorium region and the axial asymmetric first barrier in the californium region. Detailed analyses of experimental data suggest the presence of two parallel second barriers; the normal mass-asymmetric, axial-symmetric barrier and a slightly higher mass-symmetric, axial-asymmetric barrier. Experimental barrier parameters are determined systematically and compared with calculations from various theoretical models. Techniques for expanding fission probability measurements to higher energies are discussed. (author)

Environmental assessment of the thermal neutron activation explosive detection system for concourse use at US airports

International Nuclear Information System (INIS)

Jones, C.G.

1990-08-01

This document is an environmental assessment of a system designed to detect the presence of explosives in checked airline baggage or cargo. The system is meant to be installed at the concourse or lobby ticketing areas of US commercial airports and uses a sealed radioactive source of californium-252 to irradiate baggage items. The major impact of the use of this system arises from direct exposure of the public to scattered or leakage radiation from the source and to induced radioactivity in baggage items. Under normal operation and the most likely accident scenarios, the environmental impacts that would be created by the proposed licensing action would not be significant. 44 refs., 19 figs., 18 tabs

Review of microscopic integral cross section data in fundamental reactor dosimetry benchmark neutron fields

International Nuclear Information System (INIS)

Fabry, A.; McElroy, W.N.; Kellogg, L.S.; Lippincott, E.P.; Grundl, J.A.; Gilliam, D.M.; Hansen, G.E.

1976-10-01

The paper is intended to review and critically discuss microscopic integral cross section measurement and calculation data for fundamental reactor dosimetry benchmark neutron fields. Specifically the review covers the following fundamental benchmarks: (1) the spontaneous californium-252 fission neutron spectrum standard field; (2) the thermal-neutron induced uranium-235 fission neutron spectrum standard field; (3) the (secondary) intermediate-energy standard neutron field at the center of the Mol-ΣΣ, NISUS, and ITN--ΣΣ facilities; (4) the reference neutron field at the center of the Coupled Fast Reactor Measurement Facility (CFRMF); (5) the reference neutron field at the center of the 10 percent enriched uranium metal, cylindrical, fast critical; and (6) the (primary) Intermediate-Energy Standard Neutron Field

Californium-252 neutron activation analysis of high-level processed nuclear tank waste

International Nuclear Information System (INIS)

Troyer, G.L.; Purcell, M.A.

2000-01-01

The basis for production assessment of the vitrification of Hanford nuclear fuel reprocessing wastes will be high-precision measurements of the elemental sodium content. However, the chemical analysis of both radioactive and nonradioactive components in nuclear waste can be challenged by high radiation dose rates. The dose rates compromise many analytical techniques as well as pose personnel dosimetry risks. In many cases, reduction of dose rates through dilution compromises the precision and sensitivity for certain key components. The use of neutron activation analysis (NAA) provides a method of analysis that avoids the need for dilutions or extensive sample preparation. These waste materials also contain trace quantities of fissionable isotopes, which, through neutron activation, can be estimated by delayed neutron counting of fissioned fragments

Californium-252: isotope for modern radiotherapy of cervix, uterine and vaginal carcinomas

International Nuclear Information System (INIS)

Maruyama, J.; Beach, J.L.; Nagell, J.R. van

1984-01-01

Cf-252 is an isotope that can easily be afterloaded into available gynecological applicators and used for bulky cervix, uterus or vaginal cancer therapy. It is economical, time and cost effective in use, and can be applied to the therapy of many patients throughout the world. It is more effective for neutron therapy than machine fast neutron therapy and is the only form of neutron therapy producing consistent complication-free 5-year cure of advanced cancers currently available. Cf-252 is an isotope for modern gynecological tumor therapy for the future. Isodose curves for Cf-252 implants revealed dose distributions conforming well to tumor. (orig.) [de

A confocal laser scanning microscopic study on thermoresponsive

Indian Academy of Sciences (India)

Monodisperse poly(N -isopropylacrylamide) (PNIPAM) particles loaded with cadmium telluride (CdTe) quantum dots (QDs) of two different sizes (4.7 nm and 5.6 nm) were synthesized in aqueous medium by bonding the capping agent on the quantum dots to the amide groups of PNIPAM and incubating the samples at 45° ...

solution growth and characterization of copper oxide thin films ...

African Journals Online (AJOL)

Thin films of copper oxide (CuO) were grown on glass slides by using the solution growth technique. Copper cloride (CuCl ) and potassium telluride (K T O ) were used. Buffer 2 2e 3 solution was used as complexing agent. The solid state properties and optical properties were obtained from characterization done using PYE ...

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. S. V. Vadawale. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 2 June 2017 pp 31 Review Article. The Cadmium Zinc Telluride Imager on AstroSat · V. Bhalerao D. Bhattacharya A. Vibhute P. Pawar A. R. Rao M. K. Hingar Rakesh Khanna ...

Economic viability of thin-film tandem solar modules in the United States

Science.gov (United States)

Sofia, Sarah E.; Mailoa, Jonathan P.; Weiss, Dirk N.; Stanbery, Billy J.; Buonassisi, Tonio; Peters, I. Marius

2018-05-01

Tandem solar cells are more efficient but more expensive per unit area than established single-junction (SJ) solar cells. To understand when specific tandem architectures should be utilized, we evaluate the cost-effectiveness of different II-VI-based thin-film tandem solar cells and compare them to the SJ subcells. Levelized cost of electricity (LCOE) and energy yield are calculated for four technologies: industrial cadmium telluride and copper indium gallium selenide, and their hypothetical two-terminal (series-connected subcells) and four-terminal (electrically independent subcells) tandems, assuming record SJ quality subcells. Different climatic conditions and scales (residential and utility scale) are considered. We show that, for US residential systems with current balance-of-system costs, the four-terminal tandem has the lowest LCOE because of its superior energy yield, even though it has the highest US per watt (US W-1) module cost. For utility-scale systems, the lowest LCOE architecture is the cadmium telluride single junction, the lowest US W-1 module. The two-terminal tandem requires decreased subcell absorber costs to reach competitiveness over the four-terminal one.

Double beta decay of tellurium-130

International Nuclear Information System (INIS)

Richardson, J.F.; Manuel, O.K.; Sinha, B.; Thorpe, R.I.

1986-01-01

The isotopic composition of xenon is reported in four, neutron-irradiated tellurium minerals - tellurobismuthite from Boliden, Sweden, native tellurium from the Good Hope Mine of Gunnison County, Colorado, altaite from the Kirkland Lake area, Ontario, and altaite from the Mattagami Lake area, Quebec. From the amount of radiogenic 130 Xe and pile-produced 131 Xe in these samples, it is concluded that the half-life of 130 Te for ββ-decay is 21 y based on measured values of (1.0+-0.3) . 10 21 y and higher. Our results demonstrate that there has been no significant partial leakage of radiogenic 130 Xe from these minerals over geologic time. Larger values of Tsub(1/2), as indicated from some of the analysis reported here and in other studies, are attributed to recrystallization of the soft telluride minerals and complete resetting of the Te-Xe system after mineralization. The value obtained here for the half-life of 130 Te is substantiated by recent measurements on xenon in tellurides from Kalgoorlie, Western Australia. (orig.)

Composition and genesis of the Konevinsky gold deposit, Eastern Sayan, Russia

Science.gov (United States)

Damdinov, B. B.; Zhmodik, S. M.; Roshchektaev, P. A.; Damdinova, L. B.

2016-03-01

The Konevinsky gold deposit in southeast Eastern Sayan is distinguished from most known deposits in this region (Zun-Kholba, etc.) by the geological setting and composition of mineralization. To elucidate the cause of the peculiar mineralization, we have studied the composition, formation conditions, and origin of this deposit, which is related to the Ordovician granitoid pluton 445-441 Ma in age cut by intermediate and basic dikes spatially associated with metavolcanic rocks of the Devonian-Carboniferous Ilei Sequence. Four mineral assemblages are recognized: (1) quartz-pyrite-molybdenite, (2) quartz-gold-pyrite, (3) gold-polysulfide, and (4) telluride. Certain indications show that the ore was formed as a result of the superposition of two distinct mineral assemblages differing in age. The first stage dated at ~440 Ma is related to intrusions generating Cu-Mo-Au porphyry mineralization and gold-polysulfide veins. The second stage is controlled by dikes pertaining to the Devonian-Carboniferous volcanic-plutonic association. The second stage is characterized by gain of Hg and Te and formation of gold-mercury-telluride paragenesis.

Characterization inconsistencies in CdTe and CZT gamma-ray detectors

International Nuclear Information System (INIS)

Lavietes, A.D.; McQuaid, J.H.

1994-10-01

In the past few years, significant developments in cadmium telluride (CdTe) and cadmium zinc telluride (CZT) semiconductor materials have taken place with respect to both quality and yield. Many of the more recent developments have occurred in the area of CZT crystal growth. This has resulted in an explosion of interest in the use of these materials in ambient temperature gamma-ray detectors. Most, if not all, of the manufacturers of CdTe and CZT have acquired government funding to continue research in development and applications, indicating the importance of these improvements in material quality. We have examined many detectors, along with the accompanying manufacturer's data, and it has become apparent that a clear standard does not exist by which each manufacturer characterizes the performance of their material. Result is a wide variety of performance claims that have no basis for comparison and normally cannot be readily reproduced. This paper first supports our observations and then proposes a standard that all manufacturers and users of these materials may use for characterization

Synthesis and X-ray structures of dilithium complexes of the phosphonate anions [PhP(E)(N(t)Bu)(2)](2-) (E = O, S, Se, Te) and dimethylaluminum derivatives of [PhP(E)(N(t)Bu)(NH(t)Bu)](-) (E = S, Se).

Science.gov (United States)

Briand, Glen G; Chivers, Tristram; Krahn, Mark; Parvez, Masood

2002-12-16

The dilithium salts of the phosphonate dianions [PhP(E)(N(t)Bu)(2)](2-) (E = O, S, Se) are generated by the lithiation of [PhP(E)(NH(t)Bu)(2)] with n-butyllithium. The formation of the corresponding telluride (E = Te) is achieved by oxidation of [Li(2)[PhP(N(t)Bu)(2)

Journal of Astrophysics and Astronomy | Indian Academy of Sciences

Indian Academy of Sciences (India)

Home; Journals; Journal of Astrophysics and Astronomy. P. Priya. Articles written in Journal of Astrophysics and Astronomy. Volume 38 Issue 2 June 2017 pp 31 Review Article. The Cadmium Zinc Telluride Imager on AstroSat · V. Bhalerao D. Bhattacharya A. Vibhute P. Pawar A. R. Rao M. K. Hingar Rakesh Khanna A. P. K. ...

FOR CU-DOPED ZnS 'ALLOY

African Journals Online (AJOL)

2005-01-20

Jan 20, 2005 ... electron transport property of thin films. may be characterized by the conductivity of the ... 3H20 were prepared and added drop by drop' to. 100ml of ZnS .... higher temperatures there is sufficient thermal activation fo~. I some electrons to .... telluride film on crystalline silicon, J. Appl. Phys. 54 (3): 1383-1389.

Induced superconductivity in the topological insulator mercury telluride

International Nuclear Information System (INIS)

Maier, Luis

2015-01-01

The combination of a topological insulator (TI) and a superconductor (S), which together form a TI/S interface, is expected to influence the possible surface states in the TI. It is of special interest, if the theoretical prediction of zero energy Majorana states in this system is verifiable. This thesis presents the experimental realization of such an interface between the TI strained bulk HgTe and the S Nb and studies if the afore mentioned expectations are met. As these types of interfaces were produced for the first time the initial step was to develop a new lithographic process. Optimization of the S deposition technique as well as the application of cleaning processes allowed for reproducible fabrication of structures. In parallel the measurement setup was upgraded to be able to execute the sensitive measurements at low energy. Furthermore several filters have been implemented into the system to reduce high frequency noise and the magnetic field control unit was additionally replaced to achieve the needed resolution in the μT range. Two kinds of basic geometries have been studied: Josephson junctions (JJs) and superconducting quantum interference devices (SQUIDs). A JJ consists of two Nb contacts with a small separation on a HgTe layer. These S/TI/S junctions are one of the most basic structures possible and are studied via transport measurements. The transport through this geometry is strongly influenced by the behavior at the two S/TI interfaces. In voltage dependent differential resistance measurements it was possible to detect multiple Andreev reflections in the JJ, indicating that electrons and holes are able to traverse the HgTe gap between both interfaces multiple times while keeping phase coherence. Additionally using BTK theory it was possible to extract the interface transparency of several junctions. This allowed iterative optimization for the highest transparency via lithographic improvements at these interfaces. The increased transparency and thus the increased coupling of the Nb's superconductivity to the HgTe results in a deeper penetration of the induced superconductivity into the HgTe. Due to this strong coupling it was possible to enter the regime, where a supercurrent is carried through the complete HgTe layer. For the first time the passing of an induced supercurrent through strained bulk HgTe was achieved and thus opened the area for detailed studies. The magnetic dependence of the supercurrent in the JJ was recorded, which is also known as a Fraunhofer pattern. The periodicity of this pattern in magnetic field compared to the JJ geometry allowed to conclude how the junction depends on the phase difference between both superconducting contacts. Theoretical calculations predicted a phase periodicity of 4π instead of 2π, if a TI is used as weak link material between the contacts, due to the presence of Majorana modes. It could clearly be shown that despite the usage of a TI the phase still was 2π periodic. By varying further influencing factors, like number of modes and phase coherence length in the junction, it might still be possible to reach the 4π regime with bound Majorana states in the future. A good candidate for further experiments was found in capped HgTe samples, but here the fabrication process still has to be developed to the same quality as for the uncapped HgTe samples. The second type of geometry studied in this thesis was a DC-SQUID, which consists of two parallel JJs and can also be described as an interference device between two JJs. The DC-SQUID devices were produced in two configurations: The symmetric SQUID, where both JJs were identical, and the asymmetric SQUID, where one JJ was not linear, but instead has a 90 bent. These configurations allow to test, if the predicted uniformity of the superconducting band gap for induced superconductivity in a TI is valid. While the phase of the symmetric SQUID is not influenced by the shape of the band gap, the asymmetric SQUID would be in phase with the symmetric SQUID in case of an uniform band gap and out of phase if p- or d-wave superconductivity is dominating the transport, due to the 90° junction. As both devices are measured one after another, the problem of drift in the coil used to create the magnetic field has to be overcome in order to decide if the oscillations of both types of SQUIDs are in phase. With an oscillation period of 0.5 mT and a drift rate in the range of 5.5 μT/h the measurements on both configurations have to be conducted in a few hours. Only then the total shift is small enough to compare them with each other. For this to be possible a novel measurement system based on a real time micro controller was programmed, which allows a much faster extraction of the critical current of a device. The measurement times were reduced from days to hours, circumventing the drift problems and enabling the wanted comparison. After the final system optimizations it has been shown that the comparison should now be possible. Initial measurements with the old system hinted that both types of SQUIDs are in phase and thus the expected uniform band gap is more likely. With all needed optimizations in place it is now up to the successors of this project to conclusively prove this last point. This thesis has proven that it is possible to induce superconductivity in strained bulk HgTe. It has thus realized the most basic sample geometry proposed by Fu and Kane in 2008 for the appearance of Majorana bound states. Based on this work it is now possible to further explore induced superconductivity in strained bulk HgTe to finally reach a regime, where the Majorana states are both stable and detectable.

Mechanisms of component diffusion in mercury cadmium telluride

International Nuclear Information System (INIS)

Tang, M.S.; Stevenson, D.A.

1989-01-01

The component diffusion coefficients for the Hg/sub 0.8/Cd/sub 0.2/Te (MCT) system are measured using radioactive tracers. Multiple branches are observed in the tracer diffusion profiles which are related to fast and slow-diffusing components. Diffusion models for each component are proposed based on the defect chemistry of MCT, a calculation of the thermodynamic factor, and the relationship between component diffusion coefficients and the interdiffusion coefficients for pseudobinary systems. The model provides insight into the thermodynamic properties of the system, the mechanisms for diffusion, and the practical application of tracer diffusion data to interdiffusion and p-to-n conversion by Hg annealing

Deposition of antimony telluride thin film by ECALE

Institute of Scientific and Technical Information of China (English)

GAO; Xianhui; YANG; Junyou; ZHU; Wen; HOU; Jie; BAO; Siqian; FAN; Xi'an; DUAN; Xingkai

2006-01-01

The process of Sb2Te3 thin film growth on the Pt substrate by electrochemical atomic layer epitaxy (ECALE) was studied. Cyclic voltammetric scanning was performed to analyze the electrochemical behavior of Te and Sb on the Pt substrate. Sb2Te3 film was formed using an automated flow deposition system by alternately depositing Te and Sb atomic layers for 400 circles. The deposited Sb2Te3 films were characterized by XRD, EDX, FTIR and FESEM observation. Sb2Te3 compound structure was confirmed by XRD pattern and agreed well with the results of EDX quantitative analysis and coulometric analysis. FESEM micrographs showed that the deposit was composed of fine nano particles with size of about 20 nm. FESEM image of the cross section showed that the deposited films were very smooth and dense with thickness of about 190 nm. The optical band gap of the deposited Sb2Te3 film was determined as 0.42 eV by FTIR spectroscopy, and it was blue shifted in comparison with that of the bulk Sb2Te3 single crystal due to its nanocrystalline microstructure.

Synthesis of copper telluride nanowires using template-based ...

Indian Academy of Sciences (India)

Anodized alu- minum oxide foil (AAO) acts as template and electrodeposi- tion is conducted in a ... the nanopores were perpendicular to the AAO membrane sur- face and were uniform in ... Aluminium oxide 0·02–0·2. 13, 21, 47. 60. 105. –.

Acceptors in cadmium telluride. Identification and electronic structure

International Nuclear Information System (INIS)

Molva, E.

1983-11-01

It is shown that electronic properties of CdTe are determined by impurities more than by intrinsic defects like vacancies or interstitials in Cd or Te contrary to classical theories. These results are based on annealing, diffusion, implantation and electron irradiation at 4 K. Centers appearing in treated samples are accurately identified by photoluminescence, cathodoluminescence infra-red absorption, electrical measurements and magneto-optic properties. Acceptors identified are Li, Na, Cu, Ag and Au impurities in Cd and N, P and As in Te. Energy levels of all acceptors and fine structure of excitons are determined [fr

The Cadmium Zinc Telluride Imager on AstroSat

Indian Academy of Sciences (India)

V. Bhalerao

2017-06-19

Jun 19, 2017 ... which act as the interface to the satellite. The overall dimensions of ... plate affixed on a side to dissipate heat and provide a cold bias for maintaining ... patterns, with some repeats, were placed in the form of a 4 × 4 matrix to ...

Cadmium Telluride and Grain Boundaries: A Preliminary Study

Science.gov (United States)

Liao, Michael Evan

The efficacy of the CdCl2 treatment on polycrystalline CdTe-based solar cells was discovered over a quarter of a century ago; and yet, the exact mechanism of this treatment is still not fully understood to this day. In fact, the lack of understanding stems from a debate on the exact role of grain boundaries in CdCl2-treated CdTe solar cells. Some hypothesize that the CdCl2-treatment causes grain boundaries to become beneficial to solar cell performance while others disagree and claim that the treatment simply mitigates the harmful effects of grain boundaries via passivation. A future goal of this project is to determine which, if either, hypothesis is correct by direct wafer bonding single crystalline CdTe. Direct wafer bonding of single crystalline materials would create only one grain boundary at the bonded interface. This approach allows the orientation and surface chemistry of interfaces to be controlled in order to study the chemistry of grain boundaries methodically. However, before any direct wafer bonding can be done, a preliminary study of single crystalline CdTe is necessary. High-quality direct wafer bonding can only be achieved if the surfaces of each wafer satisfy certain requirements. Additionally, analyzing single crystalline CdTe materials prior to bonding is crucial in order to make any insightful connections between results found from direct bonding of single crystalline CdTe and what is observed in polycrystalline CdTe. First, the surface of an (001) CdTe layer epitaxially grown on an (001) InSb substrate is studied using atomic force microscopy. Stacking faults on the CdTe surface are observed and the thickness of the grown CdTe epilayer is calculated by considering the interplanar angles between the (001) and (111) crystallographic planes as well as the dimensions of the stacking faults. While the stacking faults will inhibit successful wafer bonding, the roughness of the regions outside the stacking faults is 0.9 nm, which is an acceptable roughness for direct wafer bonding. High resolution x-ray diffraction is used to study the strain of the CdTe epilayer at the epilayer-substrate interface by generating reciprocal space maps of the (004), (115), and (335) crystallographic planes. It is found that CdTe grown on an (001) InSb substrate at a low growth temperature exhibits nearly 0% relaxation. As a result, the in-plane lattice parameter of the CdTe layer is maximally strained to match the smaller lattice parameter of the InSb substrate. Consequently, the CdTe lattice is tetragonally strained normal to the substrate surface, which causes the out-of-plane lattice parameter of CdTe to be larger than its intrinsic value. Lastly, a CdCl2-treated CdTe-CdS (p-type CdTe on n-type CdS) solar cell structure is simulated using a semiconductor-heterojunction simulation program. In literature, it has been reported that chlorine atoms from the treatment segregate along grain boundaries in polycrystalline CdTe and cause the formation of local p-n junctions by inverting the grain boundaries to n-type. The simulated structure includes one grain and 2 grain boundaries. The grain/bulk CdTe material is p-type while the grain boundaries are made to be n-type with varying doping concentrations. Both the conduction band and valence band energy exhibit downward sloping from the CdTe surface to the CdTe-CdS interface. This structure assumes that the grain boundaries are parallel to the CdTe-CdS interface. While these simulations do not prove the existence of the local type-inversion hypothesis, they do entertain a novel possibility for future devices fabrication methods.

The melt-growth and characterization of cadmium telluride

International Nuclear Information System (INIS)

Mullin, J.B.; Straughan, B.W.

1977-01-01

Developments in the melt-growth of CdTe are reviewed particularly with respect to techniques for controlling the dissociation pressure. The potential merits of Pressure Balancing are considered together with the results of a preliminary LEC growth investigation. The characterization, dislocations, precipitates, impurities and impurity defects-together with a discussion on their origin, and experience and suggestions for their elimination or control

A new type-B cask design for transporting 252Cf

International Nuclear Information System (INIS)

Simmons, C.M.

2000-01-01

A project to design, certify, and build a new US Department of Energy (DOE) Type B container for transporting >5 mg of 252 Cf is more than halfway to completion. This project was necessitated by the fact that the existing Oak Ridge National Laboratory (ORNL) Type B containers were designed and built many years ago and thus do not have the records and supporting data that current regulations require. Once the new cask is available, it will replace the existing Type B containers. The cask design is driven by the unique properties of 252 Cf, which is a very intense spontaneous fission neutron source and necessitates a large amount of neutron shielding. The cask is designed to contain up to 60 mg of 252 Cf in the form of californium oxide or californium oxysulfate, in pellet, wire, or sintered material forms that are sealed inside small special-form capsules. The new cask will be capable of all modes of transport (land, sea, and air). The ORNL team, composed of technical and purchasing personnel and using rigorous selection criteria, chose NAC, International (NAC), as the subcontractor for the project. In January 1997, NAC started work on developing the conceptual design and performing the analyses. The original design concept was for a tungsten alloy gamma shield surrounded by two concentric shells of NS-4-FR neutron shield material. A visit to US Nuclear Regulatory Commission (NRC) regulators in November 1997 to present the conceptual design for their comments resulted in a design modification when the question of potential straight-line cracking in the NS-4-FR neutron shield material arose. NAC's modified design includes offset, wedgelike segments of the neutron shield material. The new geometry eliminates concerns about straight-line cracking but increases the weight of the packaging and makes the fabrication more complex. NAC has now completed the cask design and performed the analyses (shielding, structural, thermal, etc.) necessary to certify the cask. The cask

Left ventricular function assessment using 123I/99mTc dual-isotope acquisition with two semi-conductor cadmium–zinc–telluride (CZT cameras: a gated cardiac phantom study

Directory of Open Access Journals (Sweden)

Tanguy Blaire

2016-11-01

Full Text Available Abstract Background The impact of increased energy resolution of cadmium–zinc–telluride (CZT cameras on the assessment of left ventricular function under dual-isotope conditions (99mTc and 123I remains unknown. The Amsterdam-gated dynamic cardiac phantom (AGATE, Vanderwilt techniques, Boxtel, The Netherlands was successively filled with a solution of 123I alone, 99mTc alone, and a mixture of 123I and 99mTc. A total of 12 datasets was acquired with each commercially available CZT camera (DNM 530c, GE Healthcare and DSPECT, Biosensors International using both energy windows (99mTc or 123I with ejection fraction set to 33, 45, and 60 %. End-diastolic (EDV and end-systolic (ESV volumes, ejection fraction (LVEF, and regional wall motion and thickening (17-segment model were assessed using Cedars-Sinai QGS Software. Concordance between single- and dual-isotope acquisitions was tested using Lin’s concordance correlation coefficient (CCC and Bland–Altman plots. Results There was no significant difference between single- or simultaneous dual-isotope acquisition (123I and 99mTc for EDV, ESV, LVEF, or segmental wall motion and thickening. Myocardial volumes using single- (123I, 99mTc and dual-isotope (reconstructed using both 123I and 99mTc energy windows acquisitions were, respectively, the following: EDV (mL 88 ± 27 vs. 89 ± 27 vs. 92 ± 29 vs. 90 ± 26 for DNM 530c (p = NS and 82 ± 20 vs. 83 ± 22 vs. 79 ± 19 vs. 77 ± 20 for DSPECT (p = NS; ESV (mL 40 ± 1 vs. 41 ± 2 vs. 41 ± 2 vs. 42 ± 1 for DNM 530c (p = NS and 37 ± 5 vs. 37 ± 1 vs. 35 ± 3 vs. 34 ± 2 for DSPECT (p = NS; LVEF (% 52 ± 14 vs. 51 ± 13 vs. 53 ± 13 vs. 51 ± 13 for DNM 530c (p = NS and 52 ± 16 vs. 54 ± 13 vs. 54 ± 14 vs. 54 ± 13 for DSPECT (p = NS; regional motion (mm 6.72 ± 2.82 vs. 6.58 ± 2.52 vs. 6.86 ± 2.99 vs. 6.59 ± 2

Physical-chemical studies of transuranium elements: Progress report for the period April 1, 1985-March 31, 1988

International Nuclear Information System (INIS)

Peterson, J.R.

1987-01-01

New knowledge is being accumulated in the role of the 5f electrons in the bonding in actinide elements and compounds, the relationships of metallic structures to metallic valence and radius, the extent and magnitude of the actinide contraction, the magnetic, thermodynamic, spectroscopic, and crystallographic properties of these materials as related to general theories, the effect of self-irradiation on chemical and physical properties, the chemical and physical consequences of radioactive decay in the bulk-phase solid state, and in general, the range of validity of the actinide hypothesis. Separate reports are given on: spectrophotometric studies of Cf(III) ions in lanthanide trihalide hosts, new ternary transplutonium chalcogenide halides, Raman spectrometric studies of lanthanide trihalides as function of T or P, and solution calorimetry of californium halides

Radionuclide toxicity

International Nuclear Information System (INIS)

Galle, P.

1982-01-01

The aim of this symposium was to review the radionuclide toxicity problems. Five topics were discussed: (1) natural and artificial radionuclides (origin, presence or emission in the environment, human irradiation); (2) environmental behaviour of radionuclides and transfer to man; (3) metabolism and toxicity of radionuclides (radioiodine, strontium, rare gas released from nuclear power plants, ruthenium-activation metals, rare earths, tritium, carbon 14, plutonium, americium, curium and einsteinium, neptunium, californium, uranium) cancerogenous effects of radon 222 and of its danghter products; (4) comparison of the hazards of various types of energy; (5) human epidemiology of radionuclide toxicity (bone cancer induction by radium, lung cancer induction by radon daughter products, liver cancer and leukaemia following the use of Thorotrast, thyroid cancer; other site of cancer induction by radionuclides) [fr

Fabrication of 50-mg 252Cf neutron sources for the FDA [Food and Drug Administration] activation analysis facility

International Nuclear Information System (INIS)

Bigelow, J.E.; Cagle, E.B.; Knauer, J.B.

1987-01-01

The Transuranium Processing Plant (TPP) at ORNL has been requested by the Food and Drug Administration (FDA) to furnish 200 mg of 252 Cf for use in their new activation analysis facility. This paper discusses the procedure to be employed in fabricating the californium into four neutron sources, each containing a nominal 50-mg of 252 Cf. The ORNL Model LSD (Large, Stainless steel, Doubly encapsulated) neutron source consists of a 6.33-mm-diam aluminum pellet doubly encapsulated in Type 304L stainless steel. The pellet is comprised of an aluminum tube holding Cf 2 O 2 SO 4 microspheres confined by pressed aluminum powder. The microspheres are prepared in a separate vessel and then transferred into the specially designed aluminum tube prior to pressing

Vavřínite Ni2SbTe2, a new mineral species from the Kunratice Cu–Ni sulfide deposit, Czech Republic

Czech Academy of Sciences Publication Activity Database

Laufek, F.; Drábek, M.; Skála, Roman; Haloda, J.; Táborský, Z.; Císařová, I.

2007-01-01

Roč. 45, č. 5 (2007), s. 1213-1219 ISSN 0008-4476 Institutional research plan: CEZ:AV0Z30130516 Keywords : vavřínite * new mineral species * Ni–Sb telluride, * electron-microprobe data * reflectance data * synthetic Ni2SbTe2, X-ray-diffraction data * crystal structure * Kunratice (Czech Republic) Subject RIV: DB - Geology ; Mineralogy Impact factor: 1.057, year: 2007

USSR and Eastern Europe Scientific Abstracts, Physics and Mathematics, Number 34

Science.gov (United States)

1977-04-27

USSR UDC 621.315.592 ANOMALOUS PHOTOCONDUCTIVITY AND DARK CONDUCTIVITY OF SEMI-INSULATING CADMIUM TELLURIDE Leningrad FIZIKA I TEKHNIKA...conductivity activation energy of CdTe. The temperature characteristic of the dark conductivity, measured within the ohmic range of the current...A. V., Joint Institute for Nuclear Research [Abstract] The purpose of this theoretical paper is to show that the quark -parton modification offers

Role of Precursor-Conversion Chemistry in the Crystal-Phase Control of Catalytically Grown Colloidal Semiconductor Quantum Wires.

Science.gov (United States)

Wang, Fudong; Buhro, William E

2017-12-26

Crystal-phase control is one of the most challenging problems in nanowire growth. We demonstrate that, in the solution-phase catalyzed growth of colloidal cadmium telluride (CdTe) quantum wires (QWs), the crystal phase can be controlled by manipulating the reaction chemistry of the Cd precursors and tri-n-octylphosphine telluride (TOPTe) to favor the production of either a CdTe solute or Te, which consequently determines the composition and (liquid or solid) state of the Bi x Cd y Te z catalyst nanoparticles. Growth of single-phase (e.g., wurtzite) QWs is achieved only from solid catalysts (y ≪ z) that enable the solution-solid-solid growth of the QWs, whereas the liquid catalysts (y ≈ z) fulfill the solution-liquid-solid growth of the polytypic QWs. Factors that affect the precursor-conversion chemistry are systematically accounted for, which are correlated with a kinetic study of the composition and state of the catalyst nanoparticles to understand the mechanism. This work reveals the role of the precursor-reaction chemistry in the crystal-phase control of catalytically grown colloidal QWs, opening the possibility of growing phase-pure QWs of other compositions.

Determination of the average number of neutrons per fission event for californium-252

International Nuclear Information System (INIS)

Aleksandrov, B.M.; Belov, L.M.; Drapchinskij, L.V.

1982-01-01

By means of a separate determination of neutron yields and fission event rates, the value of #betta#-bar( 252 Cf) has been measured for a series of new high-purity sources. The improved quality of the source active layers has reduced the error in determining the fission rate to 0.35%. The value obtained for #betta#-bar( 252 Cf) is 3.747+-0.036. A description is given of the design and the parameters of a spherical manganese bath in which the work on refining the value of #betta#-bar( 252 Cf) will be continued. (author)

Chromatographic cation exchange separation of decigram quantities of californium and other transplutonium elements

Energy Technology Data Exchange (ETDEWEB)

Benker, D.E.; Chattin, F.R.; Collins, E.D.; Knauer, J.B.; Orr, P.B.; Ross, R.G.; Wiggins, J.T.

1980-01-01

Decigram quantities of highly radioactive transplutonium elements are routinely partitioned at TRU by chromatographic elution from cation resin using AHIB eluent. By using two high-pressure ion exchange columns, a small one for the initial loading of the feed and a large one for the elution, batch runs containing up to 200 mg of /sup 252/Cf can be made in about 5 hours (2 hours to load the feed and 3 hours for the elution). The number of effluent product fractions and the amount of actinides that must be collected in intermediate fractions are minimized by monitoring response from a flow-through alpha-detector. This process has been reliable and relatively easy to operate, and will continue to be used for partitioning transplutonium elements at TRU.

Influence of different protecting groups on the regioselectivity of the hydrotelluration reaction of hydroxy alkynes

International Nuclear Information System (INIS)

Oliveira, Juliana M.; Palmeira, Dayvson J.; Menezes, Paulo H.; Comasseto, Joao V.

2010-01-01

The influence of protecting groups on the synthesis of regio- and stereodefined vinyl tellurides derived from the reaction of BuTeNa and propargylic- or homo-propargylic alcohols showed that TIPS silyl ether is useful as a regiodirecting group. The application of the methodology to the synthesis of a fragment of (±)-Seselidiol, a natural product, demonstrated the applicability of the new methodology. (author)

Emerging technologies for high performance infrared detectors

OpenAIRE

Tan Chee Leong; Mohseni Hooman

2018-01-01

Infrared photodetectors (IRPDs) have become important devices in various applications such as night vision, military missile tracking, medical imaging, industry defect imaging, environmental sensing, and exoplanet exploration. Mature semiconductor technologies such as mercury cadmium telluride and III–V material-based photodetectors have been dominating the industry. However, in the last few decades, significant funding and research has been focused to improve the performance of IRPDs such as...

NCPV preprints for the 2. world conference on photovoltaic solar energy conversion

Energy Technology Data Exchange (ETDEWEB)

NONE

1998-09-01

The proceedings contain 26 papers arranged under the following topical sections: Silicon (3 papers); Thin-film PV technologies (11 papers): amorphous silicon, cadmium telluride, copper indium diselenide, and high efficiency devices; Module and BOS manufacturing (2 papers); Cell, module, and system testing (7 papers); and Market development (3 papers). Selected papers have been indexed separately for inclusion in the Energy Science and Technology Database.

Transuranium Processing Plant semiannual report of production, status, and plans for period ending June 30, 1975

International Nuclear Information System (INIS)

King, L.J.; Bigelow, J.E.; Collins, E.D.

1976-03-01

During the period January 1, 1975, through June 30, 1975, the following amounts of transuranium elements were recovered from 22 irradiated HFIR targets: 2g 243 Am, 59 g 244 Cm, 51 mg 249 Bk, 465 mg 252 Cf, 2.5 mg 253 Es, and 1.4 pg 257 Fm. In addition, 45 mg of high-purity 248 Cm was operated from 252 Cf which had been recovered and purified during earlier periods, and 56 mg of a lower-quality 248 Cm was separated from californium purification rework solutions. Five HFIR targets, each containing approximately 9 g of actinides (predominantly curium), were fabricated. A new long-term projection showed that 252 Cf production in the TRU-HFIR complex could increase to as much as 2.5 g/year. During the next 18 months, we expect to recover totals of 46 mg of 249 Bk, 520 mg of 252 Cf, 2.0 mg of 253 Es (in a mixture of isotopes), 220 μg of high-purity 253 Es, and 1.6 pg of 257 Fm. We also expect to obtain 125 mg of high-purity 248 Cm from purified californium now in storage. There are no plans to process any of the remaining SRP Pu-Al tubes or to irradiate any plutonium targets in the HFIR; thus, we do not expect to recover any 244 Pu. Two neutron sources were fabricated, bringing the total fabricated to 77. Two sources that had been used previously in various projects were returned to the TRU inventory and are available for reassignment. In special projects, we (1) produced about 1 mg of 250 Cf by irradiation of 249 Bk in HFIR rabbits, and (2) processed some irradiated 248 Cm samples and obtained yield and isotopic composition data for use in determining the capture cross section of 249 Cm in the HFIR. The values that are currently being used for transuranium element decay data and for cross-section data in planning irradiation-processing cycles, calculating production forecasts, and assaying products are tabulated in the Appendix

Engineering of lead chalcogenide nanostructures for carrier multiplication: Core/shell, 1D, and 2D

Science.gov (United States)

Lin, Qianglu

Near infrared emitting semiconductors have been used widely in industry especially in solar-cell fabrications. The efficiency of single junction solar-cell can reach the Shockley-Queisser limit by using optimum band gap material such as silicon and cadmium telluride. The theoretical efficiency can be further enhanced through carrier multiplication, in which a high energy photon is absorbed and more than one electron-hole pair can be generated, reaching more than 100% quantum efficiency in the high energy region of sunlight. The realization of more than unity external quantum efficiency in lead selenide quantum dots solar cell has motivated vast investigation on lowering the carrier multiplication threshold and further improving the efficiency. This dissertation focuses on synthesis of lead chalcogenide nanostructures for their optical spectroscopy studies. PbSe/CdSe core/shell quantum dots were synthesized by cation exchange to obtain thick shells (up to 14 monolayers) for studies of visible and near infrared dual band emissions and carrier multiplication efficiency. By examining the reaction mechanism, a thermodynamic and a kinetic model are introduced to explain the vacancy driven cation exchange. As indicated by the effective mass model, PbSe/CdSe core/shell quantum dots has quasi-type-II band alignment, possessing electron delocalized through the entire quantum dot and hole localized in the core, which breaks down the symmetry of energy levels in the conduction and valence band, leading to hot-hole-assisted efficient multi-exciton generation and a lower carrier multiplication threshold to the theoretical value. For further investigation of carrier multiplication study, PbTe, possessing the highest efficiency among lead chalcogenides due to slow intraband cooling, is synthesized in one-dimensional and two-dimensional nanostructures. By using dodecanethiol as the surfactant, PbTe NRs can be prepared with high uniformity in width and resulted in fine quantum

Decay Curves and Half-Lives of Gamma-Emitting States from a Study of Prompt Fission Gamma Radiation

Energy Technology Data Exchange (ETDEWEB)

Albinsson, H [Chalmers Univ. of Technology, Goeteborg (SE)

1971-04-15

Measurements were made on the time distributions of the prompt gamma radiation emitted from fragments in the thermal-neutron induced fission of 235U. The gamma radiation emitted during different time intervals after the fission event was studied with the help of a collimator, the position of which was changed along the path of the fragments. In this way decay curves were obtained from which half-lives could be estimated. Time components with half-lives of 7.5, 18 and 60 ps were found and their relative intensities were calculated. Half-lives and associated intensities are in good agreement with earlier data from uranium and californium fission. Problems involved in this type of study are discussed. The collimator technique has proved to be effective for determination of half lives down to less than 10 ps

Neutron radiography for nondestructive testing

International Nuclear Information System (INIS)

John, J.

1979-01-01

Neutron radiography is similar to X-ray inspection in that both depend upon use of radiation that penetrates some materials and is absorbed by others to provide a contrast image of conditions not readily available for visual inspection. X-rays are absorbed by dense materials, such as metals, whereas neutrons readily penetrate metals, but are absorbed by materials containing hydrogen. The neutron radiography has been successfully applied to a number of inspection situations. These include the inspection of explosives, advanced composites, adhesively bonded structures and a number of aircraft engine components. With the availability of Californium-252, it has become feasible to construct mobile neutron radiography systems suitable for field use. Such systems have been used for in-situ inspection of flight line aircraft, particularly to locate and measure hidden corrosion

The CARIBU EBIS control and synchronization system

Science.gov (United States)

Dickerson, Clayton; Peters, Christopher

2015-01-01

The Californium Rare Isotope Breeder Upgrade (CARIBU) Electron Beam Ion Source (EBIS) charge breeder has been built and tested. The bases of the CARIBU EBIS electrical system are four voltage platforms on which both DC and pulsed high voltage outputs are controlled. The high voltage output pulses are created with either a combination of a function generator and a high voltage amplifier, or two high voltage DC power supplies and a high voltage solid state switch. Proper synchronization of the pulsed voltages, fundamental to optimizing the charge breeding performance, is achieved with triggering from a digital delay pulse generator. The control system is based on National Instruments realtime controllers and LabVIEW software implementing Functional Global Variables (FGV) to store and access instrument parameters. Fiber optic converters enable network communication and triggering across the platforms.

Reliability of semiconductor and gas-filled diodes for over-voltage protection exposed to ionizing radiation

Directory of Open Access Journals (Sweden)

Stanković Koviljka

2009-01-01

Full Text Available The wide-spread use of semiconductor and gas-filled diodes for non-linear over-voltage protection results in a variety of possible working conditions. It is therefore essential to have a thorough insight into their reliability in exploitation environments which imply exposure to ionizing radiation. The aim of this paper is to investigate the influence of irradiation on over-voltage diode characteristics by exposing the diodes to californium-252 combined neutron/gamma radiation field. The irradiation of semiconductor over-voltage diodes causes severe degradation of their protection characteristics. On the other hand, gas-filled over-voltage diodes exhibit a temporal improvement of performance. The results are presented with the accompanying theoretical interpretations of the observed changes in over-voltage diode behaviour, based on the interaction of radiation with materials constituting the diodes.

Designing on-line analyzer for coal on belt conveyor using neutron activation technique

International Nuclear Information System (INIS)

Rony Djokorayono; Agus Cahyono

2014-01-01

Basic design of on-line analyzer for coal on belt conveyor using neutron activation technique has been carried out. Compared with sampling technique, this neutron activation technique has some advantages in term of analysis accuracy and time. The design activities performed include the establishment of design requirements, functional requirements, technical requirements, technical specification, detection sub-system design, data acquisition subsystem design, and operator computer console design. This program will use Nal(Tl) scintillation detector to detect gamma-rays emitted by elements in coal due to neutron activation of a neutron source, "2"5"2Cf (Californium-252). This basic design of on-line analyzer for coal on belt conveyor using neutron activation technique should be followed up with the development of detailed design, prototype construction, and field testing. (author)

Nuclear assay of coal. Volume 8. Continuous nuclear assay of coal (CONAC). Final report

International Nuclear Information System (INIS)

Lagarias, J.; Irminger, P.; Dodson, W.

1979-01-01

Using californium-252 as a source of exciting neutrons, prompt gamma photons emitted by elemental nuclei in the coal have been measured using several detectors, including sodium-iodide and germanium-lithium. Several coal types, including bituminous, subbituminous lignite and anthracite were crushed to various top sizes and analyzed carefully by traditional ASTM wet chemistry techniques at two or three different laboratories. The elements (sulfur, hydrogen, carbon, aluminum, silicon, iron, calcium, sodium, nitrogen, and chlorine) were determined by prompt neutron activations and the quantities compared with those of the wet chemical analyses. Since satisfactory correlation has been obtained at bench-scale level using 100 to 200 kG samples, an apparatus has been designed to analyze a coal stream of up to 50 ton/hour, at an electric power generating station

Neutron dosimetry and spectrometry with Bonner spheres. Working out a log-normal reference matrix

International Nuclear Information System (INIS)

Zaborowski, Henrick.

1981-11-01

From the experimental and theoretical studies made upon the BONNER's spheres System with a I 6 Li(Eu) crystal and with a miniaturized 3 He counter we get the normalized energy response functions R*sub(i)(E). This normalization is obtained by the mathematization of the Resolution Function R*(i,E) in the Log-Normal distribution hypothesis to mono energetic neutrons given in April 1976 to the International Symposium on Californium 252. The fit of the Log-Normal Hypothesis with the experimental and Theoretical data is very satisfactory. The parameter's tabulated values allow a precise interpolation, at all energies between 0.4 eV and 15 MeV and for all spheres diameters between 2 and 12 inches, of the discretized R*sub(ij) Reference Matrix for the applications to neutron dosimetry and spectrometry [fr

The CARIBU EBIS control and synchronization system

Energy Technology Data Exchange (ETDEWEB)

Dickerson, Clayton, E-mail: cdickerson@anl.gov; Peters, Christopher, E-mail: cdickerson@anl.gov [Argonne National Laboratory, Argonne, IL 60439 (United States)

2015-01-09

The Californium Rare Isotope Breeder Upgrade (CARIBU) Electron Beam Ion Source (EBIS) charge breeder has been built and tested. The bases of the CARIBU EBIS electrical system are four voltage platforms on which both DC and pulsed high voltage outputs are controlled. The high voltage output pulses are created with either a combination of a function generator and a high voltage amplifier, or two high voltage DC power supplies and a high voltage solid state switch. Proper synchronization of the pulsed voltages, fundamental to optimizing the charge breeding performance, is achieved with triggering from a digital delay pulse generator. The control system is based on National Instruments realtime controllers and LabVIEW software implementing Functional Global Variables (FGV) to store and access instrument parameters. Fiber optic converters enable network communication and triggering across the platforms.

Chemical consequences of radioactive decay. 1. Study of 249Cf ingrowth into crystalline 249BkBr3: a new crystalline phase of CfBr3

International Nuclear Information System (INIS)

Young, J.P.; Haire, R.G.; Peterson, J.R.; Ensor, D.D.; Fellows, R.L.

1980-01-01

Spectrophotometric and x-ray powder diffraction methods have been applied to a study of the ingrowth of californium-249 by β - decay of berkelium-249 in crystalline 249 BkBr 3 . It was found that the Cf daughter grows in with the same oxidation state and crystal structure as the parent. Thus, six-coordinate BkBr 3 (AlCl 3 -type monoclinic structure) generates six-coordinate CfBr 3 , and eight-coordinate BkBr 3 (PuBr 3 -type orthorhombic structure) generates eight-coordinate CfBr 3 , a previously unknown form of CfBr 3 . It was also found that the daughter Cf(III) in the BkBr 3 parent compound can be reduced to Cf(II) by treatment with H 2 , as it can in pure CfBr 3 . 5 figures

Provenance and composition study on Terengganu inscribed stone using in-situ nuclear technology

International Nuclear Information System (INIS)

Jaafar Abdullah; Roslan Yahya; Hearie Hassan; Engku Mohd Fahmi Engku Chik; Mohamad Rabaie Shari; Airwan Affendi Mahmood; Abdul Quddoss Abu Bakar; Ainul Mardhiah Terry

2012-01-01

This paper focused on the analysis of trace elements and provenance study of the Inscribed Stone of Terengganu (BBPT) using Neutron-induced Prompt Gamma-Ray Techniques (NIPGAT). In this study, portable NIPGAT system was designed and developed by using volume-based measurement. It is a nondestructive testing technique for the samples. This system uses low activity of isotopic neutron radioactive source from californium-252 (Cf-252) as an irradiation source. Gamma ray spectroscopy as well as specialized computer software has been utilized to conduct the research. The study has determined that the stone was a dolerite stone based on the composition of the stone elements. Although most of the scientific data for this study have been collected, this project is still running to complete the scope of provenance study. (author)

Nuclear fission and the transuranium elements

International Nuclear Information System (INIS)

Seaborg, G.T.

1989-02-01

Many of the transuranium elements are produced and isolated in large quantities through the use of neutrons furnished by nuclear fission reactions: plutonium (atomic number 94) in ton quantities; neptunium (93), americium (95), and curium (96) in kilogram quantities; berkelium (97) in 100 milligram quantities; californium (98) in gram quantities; and einsteinium (99) in milligram quantities. Transuranium isotopes have found many practical applications---as nuclear fuel for the large-scale generation of electricity, as compact, long-lived power sources for use in space exploration, as means for diagnosis and treatment in the medical area, and as tools in numerous industrial processes. Of particular interest is the unusual chemistry and impact of these heaviest elements on the periodic table. This account will feature these aspects. 9 refs., 5 figs

Nuclear fission and the transuranium elements

Energy Technology Data Exchange (ETDEWEB)

Seaborg, G.T.

1989-02-01

Many of the transuranium elements are produced and isolated in large quantities through the use of neutrons furnished by nuclear fission reactions: plutonium (atomic number 94) in ton quantities; neptunium (93), americium (95), and curium (96) in kilogram quantities; berkelium (97) in 100 milligram quantities; californium (98) in gram quantities; and einsteinium (99) in milligram quantities. Transuranium isotopes have found many practical applications---as nuclear fuel for the large-scale generation of electricity, as compact, long-lived power sources for use in space exploration, as means for diagnosis and treatment in the medical area, and as tools in numerous industrial processes. Of particular interest is the unusual chemistry and impact of these heaviest elements on the periodic table. This account will feature these aspects. 9 refs., 5 figs.

Mechanisms of antimony interstitial penetration into cadmium telluride crystals

CERN Document Server

Nikonyuk, E S; Zakharuk, Z I; Fochuk, P M; Rarenko, A I

2001-01-01

The results of electrophysical investigations of CdTe crystals, grown by Bridgman method and doped with Sb impurity in concentrations for 10 sup 1 sup 7 -3 x 10 sup 1 sup 9 cm sup - sup 3 are presented. The analysis of the temperature dependence of Hall coefficient, current carrier mobility and photoconductivity at intrinsic excitation for samples taken from different parts of ingots allows to conclude, that Sb sub T sub e , Sb sub C sub d centers and (Sb sub T sub e Sb sub C sub d) associated appear in CdTe crystal during its doping by antimony impurity. The hole conductivity in doped crystals is controlled by A sub 3 (Sb sub T sub e) acceptors, their density not exceeding 5 x 10 sup 1 sup 6 cm sup - sup 3 , and is essentially less than the real impurity content. The ionization energy of A sub 3 acceptors is (0.28 +- 0.01) eV. In non-equilibrium conditions these acceptors play the role of adhesion centers for holes (at high temperatures) and the slow recombination centers for electrons (at low temperatures)

Property elucidation of vacuum-evaporated zinc telluride thin film ...

Indian Academy of Sciences (India)

J U Ahamed

2017-08-31

Aug 31, 2017 ... method for the deposition of ZnTe thin film as compared to other methods. ... the advantages and disadvantages of different deposition process, it was ... by a spiral resistance heater and the temperature was measured by a ...

Sheet resistance effects in mercury cadmium telluride implanted photodiodes

International Nuclear Information System (INIS)

Fiorito, G.; Gasparrini, G.; Svelto, F.

1977-01-01

The frequency response of Hg + implanted Hgsub(1-x)Cdsub(x)Te photodiodes is discussed. This analysis, evaluating both the response to fast laser pulses and the 3 dB rolloff of the diode shot-noise spectrum, showed the necessity of adopting a distributed equivalent circuit model taking into account the implanted layer sheet resistance. Frequency behaviour, in fact, proved not to match a simple p-n junction model based on a lumped standard equivalent circuit. On this basis apparent anomalies previously reported can be explained, and useful suggestions can be obtained for design and fabrication of fast detectors. (author)

Impurity states of vanadium in cadmium and zinc tellurides

International Nuclear Information System (INIS)

Gnatenko, Yu.P.; Farina, I.A.

1996-01-01

Low-temperature optical (4.5 K) and photoelectrical properties of CdTe and ZnTe crystals doped by vanadium are invetigated. The energies of carrier transition to valence and conduction bands, Mott-Habbard energy for 3d 3 -ion vanadium in both crystals are determined. The resonance of the excited 4 T l ( 4 P)-state of V 2+ -ion with the conduction band of CdTe crystal is found. 8 bibl.; 4 figs

Growth of cadmium zinc telluride by liquid phase electroepitaxy

Energy Technology Data Exchange (ETDEWEB)

Armour, N.; Dost, S. [Crystal Growth Laboratory, Faculty of Engineering, University of Victoria, Victoria BC, V8W 3P6 (Canada); Sheibani, H. [Department of Industrial Engineering, Alhosn University, Abu Dhabi (United Arab Emirates)

2006-10-15

This study was undertaken to examine the feasibility of growing CdZnTe by liquid phase electroepitaxy. Based on our successful LPEE system of GaInAs, a new crucible to grow CdZnTe was developed. The development presented numerous difficulties. The physical properties of CdZnTe make this material very difficult to grow. All components of the system were investigated. Electromigration of the solute across the solution carries species towards the growth interface. In liquid Cd-Zn-Te, the CdTe and ZnTe species remain associated, contrary to the GaInAs system. Experiments showed that LPEE growth of CdZnTe is possible and the electromigration mechanism functions well in the CdZnTe solution. Despite this, other problems remained with the new LPEE system. The preparation of the solution proved difficult without pressurizing the LPEE crucible. Control of the reaction required the use of pre-compounded CdTe and ZnTe. Proper control of the solution saturation is imperative to ensure minimal dissolution of the seed prior to growth initiation and a reasonable growth rate during growth. The solution remained an issue during the duration of growth due to the high vapor pressures of the constituents. Tellurium evaporation during growth could lower solution volume until electrical contact across the solution is broken. Careful preparation of appropriate solution volume was imperative for successful growth. In LPEE, a uniform electric current passage across the growth interface is necessary for uniform and stable growth interface. This requires the design of a uniform contact zone between the bottom graphite electrode and the seed crystal. The contact zone issue was not adequately resolved in this study. However, a number of successful growth runs were achieved despite the electrical contact problems. Results show that the LPEE of growth CdZnTe is feasible. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Growth of cadmium zinc telluride by liquid phase electroepitaxy

International Nuclear Information System (INIS)

Armour, N.; Dost, S.; Sheibani, H.

2006-01-01

This study was undertaken to examine the feasibility of growing CdZnTe by liquid phase electroepitaxy. Based on our successful LPEE system of GaInAs, a new crucible to grow CdZnTe was developed. The development presented numerous difficulties. The physical properties of CdZnTe make this material very difficult to grow. All components of the system were investigated. Electromigration of the solute across the solution carries species towards the growth interface. In liquid Cd-Zn-Te, the CdTe and ZnTe species remain associated, contrary to the GaInAs system. Experiments showed that LPEE growth of CdZnTe is possible and the electromigration mechanism functions well in the CdZnTe solution. Despite this, other problems remained with the new LPEE system. The preparation of the solution proved difficult without pressurizing the LPEE crucible. Control of the reaction required the use of pre-compounded CdTe and ZnTe. Proper control of the solution saturation is imperative to ensure minimal dissolution of the seed prior to growth initiation and a reasonable growth rate during growth. The solution remained an issue during the duration of growth due to the high vapor pressures of the constituents. Tellurium evaporation during growth could lower solution volume until electrical contact across the solution is broken. Careful preparation of appropriate solution volume was imperative for successful growth. In LPEE, a uniform electric current passage across the growth interface is necessary for uniform and stable growth interface. This requires the design of a uniform contact zone between the bottom graphite electrode and the seed crystal. The contact zone issue was not adequately resolved in this study. However, a number of successful growth runs were achieved despite the electrical contact problems. Results show that the LPEE of growth CdZnTe is feasible. (copyright 2006 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

Sulfide, selenide and telluride glassy systems for optoelectronic applications

Czech Academy of Sciences Publication Activity Database

Ležal, Dimitrij; Zavadil, Jiří; Procházka, M.

2005-01-01

Roč. 7, č. 5 (2005), 2281-2291 ISSN 1454-4164 R&D Projects: GA ČR(CZ) GA104/05/0878 Institutional research plan: CEZ:AV0Z20670512 Keywords : transmission * fluorescence spectroscopy * chalcogenide glasses * optical properties Subject RIV: CA - Inorganic Chemistry Impact factor: 1.138, year: 2005

Combustion synthesis and characterization of uranium and thorium tellurides

International Nuclear Information System (INIS)

Czechowicz, D.G.

1985-10-01

This report describes an investigation of the chemical systems uranium-tellurium and thorium-tellurium. A novel synthesis technique, combustion synthesis, which uses the exothermic heat of reaction rather than externally supplied heat, was utilized to form the phases UTe, U 3 Te 4 , and UTe 2 in the U-Te system and the phases ThTe, Th 2 Te 3 , and ThTe 2 in the Th-Te system from reactions of the type U/sub x/ + Te/sub y/ = U/sub x/Te/sub y/. With this synthetic method, U-Te and Th-Te products could be formed in a matter of seconds, and the purity of the products was often greater than that of the starting materials used. Control over final product stoichiometry was found to be very difficult. The product phase distribution observed in combustion products, as determined by x-ray diffraction, electron microprobe, and optical metallographic methods, was found to be spatially complex. Lattice constants were calculated from x-ray diffraction patterns for the compounds UTe, U 3 Te 4 , and ThTe. SOLGASMIX thermodynamic equilibrium calculations were performed using available and estimated thermodynamic data on the system U-Te-O in an attempt to understand the products formed by combustion. Adiabatic combustion reaction temperatures for specific U-Te and Th-Te reactions were also calculated utilizing available and estimated thermodynamic data. 71 refs., 31 figs., 15 tabs

Event Pre Processor for the CZT Detector on MIRAX

International Nuclear Information System (INIS)

Kendziorra, Eckhard; Schanz, Thomas; Distratis, Giuseppe; Suchy, Slawomir

2006-01-01

We describe the Event Pre Processor (EPP) for the Hard X-ray Imager (HXI) on MIRAX. The EPP provides on board data reduction and event filtering for the HXI Cadmium Zinc Telluride strip detector. Emphasis is placed upon the EPP requirements, its implementation as VHDL design in a Field Programmable Gate Array (FPGA), and the description of a test environment for both the VHDL code and the FPGA hardware

Detection of Bioaerosols Using Single Particle Thermal Emission Spectroscopy (First-year Report)

Science.gov (United States)

2012-02-01

radiance is focused into 190-mm Horiba spectrometer where the radiance is dispersed onto an ultrafast, time-gated, liquid nitrogen (LN2) cooled 32...techniques were examined, i.e., methods that rely on acoustic levitation , radiative pressure, and suspension of small particles using the photophoretic...field of view HeNe helium-neon LN2 liquid nitrogen MCT mercury cadmium telluride NA numeric aperture Nd:YAG neodymium-doped yttrium aluminum

Highlights of nuclear chemistry 1994

International Nuclear Information System (INIS)

1994-12-01

Highlights were: 1. Fission product release: benchmark calculations for severe nuclear accidents; 2. Thermochemical data for reactor materials and fission products; 3. thermochemical calculations on fuel of the high-temperature gas-cooled reactor; 4. Formation of organic tellurides during nuclear accidents?; 5. Reaction of tellurium with Zircaloy-4; 6. Transmutation of fission products; 7. The thermal conductivity of high-burnup UO 2 fuel; 8. Tritium retention in graphite. (orig./HP)

Power System Assessment for the Burnt Mountain Seismic Observatory

Science.gov (United States)

1994-03-01

monocrystalline cells and 15- 20% for polycrystalline cells. Less expensive cells, such as copper indium diselenide and cadmium telluride, have...solar cells are recommended. The silicon solar cells themselves are very reliable, however the reliability of panels and systems for field use can...is composed of four solar-cell panels each measuring 48 inches X 21 inches. The four panels in the array module are arranged, electrically, as two

Study of material properties important for an optical property modulation-based radiation detection method for positron emission tomography

OpenAIRE

Tao, Li; Daghighian, Henry M.; Levin, Craig S.

2017-01-01

We compare the performance of two detector materials, cadmium telluride (CdTe) and bismuth silicon oxide (BSO), for optical property modulation-based radiation detection method for positron emission tomography (PET), which is a potential new direction to dramatically improve the annihilation photon pair coincidence time resolution. We have shown that the induced current flow in the detector crystal resulting from ionizing radiation determines the strength of optical modulation signal. A large...

Emissions from photovoltaic life cycles.

Science.gov (United States)

Fthenakis, Vasilis M; Kim, Hyung Chul; Alsema, Erik

2008-03-15

Photovoltaic (PV) technologies have shown remarkable progress recently in terms of annual production capacity and life cycle environmental performances, which necessitate timely updates of environmental indicators. Based on PV production data of 2004-2006, this study presents the life-cycle greenhouse gas emissions, criteria pollutant emissions, and heavy metal emissions from four types of major commercial PV systems: multicrystalline silicon, monocrystalline silicon, ribbon silicon, and thin-film cadmium telluride. Life-cycle emissions were determined by employing average electricity mixtures in Europe and the United States during the materials and module production for each PV system. Among the current vintage of PV technologies, thin-film cadmium telluride (CdTe) PV emits the least amount of harmful air emissions as it requires the least amount of energy during the module production. However, the differences in the emissions between different PV technologies are very small in comparison to the emissions from conventional energy technologies that PV could displace. As a part of prospective analysis, the effect of PV breeder was investigated. Overall, all PV technologies generate far less life-cycle air emissions per GWh than conventional fossil-fuel-based electricity generation technologies. At least 89% of air emissions associated with electricity generation could be prevented if electricity from photovoltaics displaces electricity from the grid.

Radiation damage measurements in room-temperature semiconductor radiation detectors

CERN Document Server

Franks, L A; Olsen, R W; Walsh, D S; Vizkelethy, G; Trombka, J I; Doyle, B L; James, R B

1999-01-01

The literature of radiation damage measurements on cadmium zinc telluride (CZT), cadmium telluride (CT), and mercuric iodide (HgI sub 2) is reviewed and in the case of CZT supplemented by new alpha particle data. CZT strip detectors exposed to intermediate energy (1.3 MeV) proton fluences exhibit increased interstrip leakage after 10 sup 1 sup 0 p/cm sup 2 and significant bulk leakage after 10 sup 1 sup 2 p/cm sup 2. CZT exposed to 200 MeV protons shows a two-fold loss in energy resolution after a fluence of 5x10 sup 9 p/cm sup 2 in thick (3 mm) planar devices but little effect in 2 mm devices. No energy resolution effects were noted from a moderated fission spectrum of neutrons after fluences up to 10 sup 1 sup 0 n/cm sup 2 , although activation was evident. Exposures of CZT to 5 MeV alpha particles at fluences up to 1.5x10 sup 1 sup 0 alpha/cm sup 2 produced a near linear decrease in peak position with fluence and increases in FWHM beginning at about 7.5x10 sup 9 alpha/cm sup 2. CT detectors show resolution...

Far infrared properties of PbTe doped with cerium

International Nuclear Information System (INIS)

Nikolic, P.M.; Koenig, W.; Vujatovic, S.S.; Blagojevic, V.; Lukovic, D.; Savic, S.; Radulovic, K.; Urosevic, D.; Nikolic, M.V.

2007-01-01

Single crystal samples of lead telluride doped with cerium were made using the Bridgman method. Far infrared reflectivity spectra in the temperature range from 10 to 300 K are presented. The experimental data were numerically analyzed using a fitting procedure based on the plasmon-phonon interaction model and optical parameters were determined. Two additional local modes were observed at about 138 and 337 cm -1 . The origin of these local vibrational impurity modes was discussed

Characteristics of a Steadily Operating Metal Combustor

Science.gov (United States)

1976-08-01

Physique, Serie 7, Vol. 17, p. 510-576, 1899. 18. Zintl, E., Harder, A., and Dauth, B., "Gitterstruktur Der Oxyde , Sulfide, Selenide Und Telluride Des...ethyl alcohol were added to the cylinder along with three drops of alizarin Red S indicator (1%). The solution was titrated with thorium nitrate until...the appearance of a faint pink color. The thorium nitrate precipitated thorium fluoride which is insoluble in ethyl alcohol , and the indicator detected

Solar Energy and Telemedicine in West Africa : A strategic solution

OpenAIRE

Ihuoma, Phineese

2011-01-01

It is important to bring medical help to those living in West Africa. A good way to do this is by telemedicine. Telemedicine, although it uses power, can be achieved easily with solar panels, and the best solar panels are monocrystalline and cadmium telluride. Using graphical scenarios, statistical derivations, theoretical ideologies acquired from literature reviews, usability ideas and two personal case scenarios, the objective of this project was achieved. Criteria like cost, temperatur...

A new type of one-dimensional compound: Structure of Nb4(Te2)4Te4I

International Nuclear Information System (INIS)

Deng Shuiquan; Zhuang Honghui; Lu Canzhong; Huang Jinshun; Huang Jingling

1993-01-01

The new infinite-chain niobium telluride iodide has been prepared by reaction of the elements at 893 K. Nb 4 (Te 2 ) 4 Te 4 I represents a new one-dimensional structure type. The structure consists of [Nb 4 (Te 2 ) 4 Te 4 I] ∞ chains which are formed by the four-nuclear butterfly cluster units 'Nb 4 (Te 2 ) 4 Te 4 ' with the I atoms bridging between different cluster units. (orig.)

Utilization of radiation facilities at TNRC for shielding researches and related topics

Energy Technology Data Exchange (ETDEWEB)

Akki, T S [Physics Department, Nuclear Physics and Radiation Shielding Division Tajura Nuclear Research Center, Tripoli (Libyan Arab Jamahiriya)

1997-12-31

This paper presents the running shielding research activities at Tajura Nuclear research center. The main area of researches are concentrated on the investigation of different types of concrete made from local materials such as conventional concrete, Magnetite-Limonite concrete, and heat resistant concrete. The measuring techniques used were neutron-gamma spectrometry, and activation foils. The measurements were performed using collimated beam of reactor neutrons emitted from one of the horizontal channels, as well as from californium-252 neutron source. The transmitted neutron spectra through concrete barriers of different thicknesses were measured by a scintillation spectrometer with NE-213 liquid organic scintillator. A non-destructive testing of some reactor materials were also carried out using neutron and gamma ray computerized tomography technique (CT). Some experiments were also carried out related to measurements of neutron depth dose distributions inside tissue equivalent materials. 10 figs.

Dust grain charges in a nuclear-track plasma and the formation of dynamic vortex dust structures

International Nuclear Information System (INIS)

Rykov, V.A.; Khudyakov, A.V.; Filinov, V.S.; Vladimirov, V.I.; Deputatova, L.V.; Krutov, D.V.; Nefedov, A.P.; Fortov, V.E.

2002-01-01

Results are presented from Monte Carlo calculations of the electric charge of dust grains in a plasma produced during the slowing down of the radioactive decay products of californium nuclei in neon. The dust grain charging is explained for the first time as being due to the drift of electrons and ions in an external electric field. It is shown that the charges of the grains depend on their coordinates and strongly fluctuate with time. The time-averaged grain charges agree with the experimental data obtained on ordered liquidlike dust structures in a nuclear-track plasma. The time-averaged dust grain charges are used to carry out computer modeling of the formation of dynamic vortex structures observed in experiments. Evidence is obtained of the fact that the electrostatic forces experienced by the dust grains are potential in character

Transuranic biokinetic parameters for marine invertebrates--a review.

Science.gov (United States)

Ryan, T P

2002-04-01

A catalogue of biokinetic parameters for the transuranic elements plutonium, americium, curium, neptunium, and californium in marine invertebrates is presented. The parameters considered are: the seawater-animal concentration factor (CF); the sediment-animal concentration ratio (CR); transuranic assimilation efficiency; transuranic tissue distribution and transuranic elimination rates. With respect to the seawater-animal CF, authors differ considerably on how they define this parameter and a seven-point reporting system is suggested. Transuranic uptake from sediment by animals is characterised by low CRs. The assimilation efficiencies of transuranic elements in marine invertebrates are high compared to vertebrates and mammals in general and the distribution of transuranics within the body tissue of an animal is dependent on the uptake path. The elimination of transuranics from most species examined conformed to a standard biphasic exponential model though some examples with three elimination phases were identified.

Off-line commissioning of EBIS and plans for its integration into ATLAS and CARIBU

Energy Technology Data Exchange (ETDEWEB)

Ostroumov, P. N., E-mail: ostroumov@anl.gov; Barcikowski, A.; Dickerson, C. A.; Mustapha, B.; Perry, A.; Sharamentov, S. I.; Vondrasek, R. C.; Zinkann, G. [Argonne National Laboratory, Argonne, Illinois 60439 (United States)

2016-02-15

An Electron Beam Ion Source Charge Breeder (EBIS-CB) has been developed at Argonne to breed radioactive beams from the CAlifornium Rare Isotope Breeder Upgrade (CARIBU) facility at Argonne Tandem Linac Accelerator System (ATLAS). The EBIS-CB will replace the existing ECR charge breeder to increase the intensity and significantly improve the purity of reaccelerated radioactive ion beams. The CARIBU EBIS-CB has been successfully commissioned offline with an external singly charged cesium ion source. The performance of the EBIS fully meets the specifications to breed rare isotope beams delivered from CARIBU. The EBIS is being relocated and integrated into ATLAS and CARIBU. A long electrostatic beam transport system including two 180° bends in the vertical plane has been designed. The commissioning of the EBIS and the beam transport system in their permanent location will start at the end of this year.

Off-line commissioning of EBIS and plans for its integration into ATLAS and CARIBU

Science.gov (United States)

Ostroumov, P. N.; Barcikowski, A.; Dickerson, C. A.; Mustapha, B.; Perry, A.; Sharamentov, S. I.; Vondrasek, R. C.; Zinkann, G.

2016-02-01

An Electron Beam Ion Source Charge Breeder (EBIS-CB) has been developed at Argonne to breed radioactive beams from the CAlifornium Rare Isotope Breeder Upgrade (CARIBU) facility at Argonne Tandem Linac Accelerator System (ATLAS). The EBIS-CB will replace the existing ECR charge breeder to increase the intensity and significantly improve the purity of reaccelerated radioactive ion beams. The CARIBU EBIS-CB has been successfully commissioned offline with an external singly charged cesium ion source. The performance of the EBIS fully meets the specifications to breed rare isotope beams delivered from CARIBU. The EBIS is being relocated and integrated into ATLAS and CARIBU. A long electrostatic beam transport system including two 180° bends in the vertical plane has been designed. The commissioning of the EBIS and the beam transport system in their permanent location will start at the end of this year.

Robotics and remote systems applications

International Nuclear Information System (INIS)

Rabold, D.E.

1996-01-01

This article is a review of numerous remote inspection techniques in use at the Savannah River (and other) facilities. These include: (1) reactor tank inspection robot, (2) californium waste removal robot, (3) fuel rod lubrication robot, (4) cesium source manipulation robot, (5) tank 13 survey and decontamination robots, (6) hot gang valve corridor decontamination and junction box removal robots, (7) lead removal from deionizer vessels robot, (8) HB line cleanup robot, (9) remote operation of a front end loader at WIPP, (10) remote overhead video extendible robot, (11) semi-intelligent mobile observing navigator, (12) remote camera systems in the SRS canyons, (13) cameras and borescope for the DWPF, (14) Hanford waste tank camera system, (15) in-tank precipitation camera system, (16) F-area retention basin pipe crawler, (17) waste tank wall crawler and annulus camera, (18) duct inspection, and (19) deionizer resin sampling

Separation of 248Cm (III) from 252Cf (III) and its use in time resolved fluorescence spectroscopic (TRFS) studies

International Nuclear Information System (INIS)

Murali, M.S.; Nair, A.G.C.; Gujar, R.B.; Jain, A.; Tomar, B.S.; Godbole, S.V.; Reddy, A.V.R.; Manchanda, V.K.

2008-07-01

The present report gives a description of the methodology for the separation of 248 Cm(III) from decayed 252 Cf (III) waste solution. The waste solution was first assayed for 252 Cf content by neutron counting using a neutron well coincidence counter. The sample was subjected to the chemical separation of 248 Cm (III) from 252 Cf (III) following anion and cation exchange chromatography. The alpha spectrum of the separated curium fraction showed peaks due to 246 Cm and 248 Cm while the corresponding alpha spectrum of californium fraction showed 249,250,251,252 Cf. The gamma ray abundances of 249 Cf were determined with respect to its gamma rays of 387 keV and the data agreed well with that in literature. Separated Cm(III) was further characterized by recording its time resolved fluorescence spectrum (TRFS) in aqueous medium. (author)

Measurements of the neutron capture cross sections and incineration potentials of minor-actinides in high thermal neutron fluxes: Impact on the transmutation of nuclear wastes

International Nuclear Information System (INIS)

Bringer, O.

2007-10-01

This thesis comes within the framework of minor-actinide nuclear transmutation studies. First of all, we have evaluated the impact of minor actinide nuclear data uncertainties within the cases of 241 Am and 237 Np incineration in three different reactor spectra: EFR (fast), GT-MHR (epithermal) and HI-HWR (thermal). The nuclear parameters which give the highest uncertainties were thus highlighted. As a result of fact, we have tried to reduce data uncertainties, in the thermal energy region, for one part of them through experimental campaigns in the moderated high intensity neutron fluxes of ILL reactor (Grenoble). These measurements were focused onto the incineration and transmutation of the americium-241, the curium-244 and the californium-249 isotopes. Finally, the values of 12 different cross sections and the 241 Am isomeric branching ratio were precisely measured at thermal energy point. (author)

Testing of ENDF/B cross section data in the Californium-252 neutron benchmark field

International Nuclear Information System (INIS)

Mannhart, W.

1979-01-01

The fission neutron field of 252 Cf presently represents one of the most well-known neutron benchmark fields. For 13 neutron reactions which are of importance in reactor metrology, measurements of spectrum-averaged cross sections, [sigma], performed in this neutron field were compared with calculated average cross sections. This comparison allows one to draw conclusions as to the quality of different sigma(E) data taken from ENDF/B-IV, from ENDF/B-V, and from recent experiments and used in the calculation of average cross sections. The comparison includes an uncertainty analysis regarding the different uncertainty contributions of [sigma], of sigma(E), and of the spectral distribution of 252 Cf fission neutrons. Additionally, in a few examples, sensitivity studies were carried out. The sensitivity of the spectrum-averaged cross sections to individual characteristics of the sigma(E) data, such as normalization factors or shifts in the energy scale, was investigated. Similarly, the sensitivity of [sigma] to the spectral distribution of 252 Cf was determined. 4 figures, 2 tables

Total neutron cross sections of berkelium-249 and californium-249 below 100 eV

International Nuclear Information System (INIS)

Benjamin, R.W.; Harvey, J.A.; Hill, N.W.; Pandey, M.S.; Carlton, R.F.

1979-01-01

The neutron total cross sections of 249 Bk and 249 Cf have been measured from 0.03 to 100 eV using the Oak Ridge Electron Linear Accelerator (ORELA) as a source of pulsed neutrons. The 1.6 mm dia. cylindrical transmission samples contained initially up to 5.3 mg of 98% 249 Bk and 2% 249 Cf: 4.5 years later, when the final measurements were made, the composition of the samples had become 2.5% 249 Bk, 96.9% 249 Cf, and 0.6% 245 Cm. Samples were cooled with liquid nitrogen to reduce Doppler broadening. Thirty-nine resonances were identified in 249 Bk and analyzed using a single-level Breit-Wigner formalism. Fifty-five resonances were identified in 249 Cf and analyzed using an R-matrix multilevel formalism. Fifty-five resonances were identified in 249 Cf and analyzed using an R-matrix multilevel formalism. The resonance parameters obtained have been used to determine the average level spacings and the s-wave neutron and fission strength functions. Where possible, bound-level parameters were derived to fit the thermal neutron total cross section data

Assessment of a Thermoelectric Vest through Physical and Mental Performance

Science.gov (United States)

2012-04-01

system is a sandwich- type structure of doped bismuth telluride (Bi2Te3) soldered between two ceramic plates. Bi2Te3 acts as a semiconductor and after... doping , the material becomes an efficient TE. Variations in doping create P-N junctions throughout the TE. Figure 3 shows a schematic of a TE...Excalibur Sport Ergonometer was used to increase subject’s core body temperature. The Excalibur Sport is a multi-adjustable ergonometer and is

Far infrared properties of PbTe doped with cerium

Energy Technology Data Exchange (ETDEWEB)

Nikolic, P.M. [Institute of Technical Sciences SASA, Knez Mihailova 35/IV, 11000 Belgrade (Serbia)]. E-mail: nikolic@sanu.ac.yu; Koenig, W. [Max Planck Institut fuer Festkoerperforschung, Heisenbergstrasse 1, 7000 Stuttgart 80 (Germany); Vujatovic, S.S. [Institute of Technical Sciences SASA, Knez Mihailova 35/IV, 11000 Belgrade (Serbia); Blagojevic, V. [Faculty of Electronic Engineering, University of Belgrade, Bulevar Kralja Aleksandra 73, 11000 Belgrade (Serbia); Lukovic, D. [Institute of Technical Sciences SASA, Knez Mihailova 35/IV, 11000 Belgrade (Serbia); Savic, S. [Institute of Technical Sciences SASA, Knez Mihailova 35/IV, 11000 Belgrade (Serbia); Radulovic, K. [Institute of Technical Sciences SASA, Knez Mihailova 35/IV, 11000 Belgrade (Serbia); Urosevic, D. [Mathematical Institute SASA, Knez Mihailova 35/I, 11000 Belgrade (Serbia); Nikolic, M.V. [Center for Multidisciplinary Studies of the University of Belgrade, Kneza Viseslava 1, Belgrade (Serbia)

2007-05-16

Single crystal samples of lead telluride doped with cerium were made using the Bridgman method. Far infrared reflectivity spectra in the temperature range from 10 to 300 K are presented. The experimental data were numerically analyzed using a fitting procedure based on the plasmon-phonon interaction model and optical parameters were determined. Two additional local modes were observed at about 138 and 337 cm{sup -1}. The origin of these local vibrational impurity modes was discussed.

Diffusion in semiconductors, other than silicon compilation

CERN Document Server

Fisher, David J

2011-01-01

Review from Book News Inc.: Summary reports of 337 experiments provide information on the diffusion of matter and heat in 31 materials used in semiconductors. Most of the compounds are based on cadmium, gallium, indium, lead, and zinc. Mercury telluride is included however, as is silicon carbide for some reason. Each article is thoroughly referenced to the authors and publication number, date, and page. The arrangement is alphabetical by semiconductor material. Indexes cover authors, hosts, and diffusants.

Transuranium Processing Plant semiannual report of production, status, and plans for period ending June 30, 1975

Energy Technology Data Exchange (ETDEWEB)

King, L.J.; Bigelow, J.E.; Collins, E.D.

1976-03-01

During the period January 1, 1975, through June 30, 1975, the following amounts of transuranium elements were recovered from 22 irradiated HFIR targets: 2g /sup 243/Am, 59 g /sup 244/Cm, 51 mg /sup 249/Bk, 465 mg /sup 252/Cf, 2.5 mg /sup 253/Es, and 1.4 pg /sup 257/Fm. In addition, 45 mg of high-purity /sup 248/Cm was operated from /sup 252/Cf which had been recovered and purified during earlier periods, and 56 mg of a lower-quality /sup 248/Cm was separated from californium purification rework solutions. Five HFIR targets, each containing approximately 9 g of actinides (predominantly curium), were fabricated. A new long-term projection showed that /sup 252/Cf production in the TRU-HFIR complex could increase to as much as 2.5 g/year. During the next 18 months, we expect to recover totals of 46 mg of /sup 249/Bk, 520 mg of /sup 252/Cf, 2.0 mg of /sup 253/Es (in a mixture of isotopes), 220 ..mu..g of high-purity /sup 253/Es, and 1.6 pg of /sup 257/Fm. We also expect to obtain 125 mg of high-purity /sup 248/Cm from purified californium now in storage. There are no plans to process any of the remaining SRP Pu-Al tubes or to irradiate any plutonium targets in the HFIR; thus, we do not expect to recover any /sup 244/Pu. No changes were made in the chemical processing flowsheets normally used at TRU. Two neutron sources were fabricated, bringing the total fabricated to 77. In special projects, we (1) produced about 1 mg of /sup 250/Cf by irradiation of /sup 249/Bk in HFIR rabbits, and (2) processed some irradiated /sup 248/Cm samples and obtained yield and isotopic composition data for use in determining the capture cross section of /sup 249/Cm in the HFIR. The values that are currently being used for transuranium element decay data and for cross-section data in planning irradiation-processing cycles, calculating production forecasts, and assaying products are tabulated in the Appendix.

Analysis Of Power Characteristics Of Model Thermoelectric Generator TEG Small Modular

Directory of Open Access Journals (Sweden)

Kisman H. Mahmud

2017-04-01

Full Text Available Thermoelectrically Generator TEG can generate electricity from the temperature difference between hot and cold at the junction thermoelectric module with two different semiconductor materials there will be a flow of current through the junction so as to produce a voltage. This principle uses the Seebeck effect thermoelectric generator as a base. By using these principles this research was conducted to determine the potential of the electric energy of the two peltier modules which would be an alternative source for mobile charger using heat from source of methylated. The focus in this research is the testing of the model TEG Thermoelectric Generator Small Modular to generate power with a variety of different materials of 4 namely Bi2Te3 Bismuth Telluride PbTe-Bite CMO and CMO Cascade-32-62S-32-62S Calcium Mangan oxide to use the cold side heat sink and a fan to simulate heat aluminum plate attached to the hot side of the TEG modules with heat source of methylated. Test results on the TEG Small Modular Model for mobile charger output voltage obtained from 2 pieces Bi2Te3 module Bismuth Telluride Peltier strung together a series of 3.01 Volt with amp916T of 22.7 C which produce power of 0.091 Watt.

From phase-change materials to thermoelectrics?

Energy Technology Data Exchange (ETDEWEB)

Schneider, Matthias N.; Rosenthal, Tobias; Oeckler, Oliver [Dept. of Chemistry, Ludwig Maximilian Univ. Munich (Germany); Stiewe, Christian [German Aerospace Center, Cologne (Germany)

2010-07-01

Metastable tellurides play an important role as phase-change materials in data storage media and non-volatile RAM devices. The corresponding crystalline phases with very simple basic structures are not stable as bulk materials at ambient conditions, however, for a broad range of compositions they represent stable high-temperature phases. In the system Ge/Sb/Te, rocksalt-type high-temperature phases are characterized by a large number of vacancies randomly distributed over the cation position, which order as 2D vacancy layers upon cooling. Short-range order in quenched samples produces pronounced nanostructures by the formation of twin domains and finite intersecting vacancy layers. As phase-change materials are usually semimetals or small-bandgap semiconductors and efficient data storage requires low thermal conductivity, bulk materials with similar compositions and properties can be expected to exhibit promising thermoelectric characteristics. Nanostructuring by phase transitions that involve partial vacancy ordering may enhance the efficiency of such thermoelectrics. We have shown that germanium antimony tellurides with compositions close to those used as phase-change materials in rewritable Blu-Ray Discs, e.g. (GeTe){sub 12}Sb{sub 2}Te{sub 3}, exhibit thermoelectric figures of merit of up to ZT = 1.3 at 450 C if a nanodomain structure is induced by rapidly quenching the cubic high-temperature phase. Structural changes have been elucidated by X-ray diffraction and high-resolution electron microscopy. (orig.)

IDeF-X ECLAIRs: A CMOS ASIC for the Readout of CdTe and CdZnTe Detectors for High Resolution Spectroscopy

International Nuclear Information System (INIS)

Gevin, O.; Baron, P.; Coppolani, X.; Delagnes, E.; Lugiez, F.; Daly, F.; Limousin, O.; Meuris, A.; Pinsard, F.; Renaud, D.

2009-01-01

The very last member of the IDeF-X ASIC family is presented: IDeF-X ECLAIRs is a 32-channel front end ASIC designed for the readout of Cadmium Telluride (CdTe) and Cadmium Zinc Telluride (CdZnTe) Detectors. Thanks to its noise performance (Equivalent Noise Charge floor of 33 e - rms) and to its radiation hardened design (Single Event Latch-up Linear Energy Transfer threshold of 56 MeV.cm 2 .mg -1 ), the chip is well suited for soft X-rays energy discrimination and high energy resolution, 'space proof', hard X-ray spectroscopy. We measured an energy low threshold of less than 4 keV with a 10 pF input capacitor and a minimal reachable sensitivity of the Equivalent Noise Charge (ENC) to input capacitance of less than 7e - /pF obtained with a 6 μs peak time. IDeF-X ECLAIRs will be used for the readout of 6400 CdTe Schottky mono-pixel detectors of the 2D coded mask imaging telescope ECLAIRs aboard the SVOM satellite. IDeF-X ECLAIRs (or IDeF-X V2) has also been designed for the readout of a pixelated CdTe detector in the miniature spectro-imager prototype Caliste 256 that is currently foreseen for the high energy detector module of the Simbol-X mission. (authors)

IDeF-X ECLAIRs: A CMOS ASIC for the Readout of CdTe and CdZnTe Detectors for High Resolution Spectroscopy

Science.gov (United States)

Gevin, Olivier; Baron, Pascal; Coppolani, Xavier; Daly, FranÇois; Delagnes, Eric; Limousin, Olivier; Lugiez, Francis; Meuris, Aline; Pinsard, FrÉdÉric; Renaud, Diana

2009-08-01

The very last member of the IDeF-X ASIC family is presented: IDeF-X ECLAIRs is a 32-channel front end ASIC designed for the readout of Cadmium Telluride (CdTe) and Cadmium Zinc Telluride (CdZnTe) Detectors. Thanks to its noise performance (Equivalent Noise Charge floor of 33 e- rms) and to its radiation hardened design (Single Event Latchup Linear Energy Transfer threshold of 56 MeV.cm2.mg-1), the chip is well suited for soft X-rays energy discrimination and high energy resolution, ldquospace proof,rdquo hard X-ray spectroscopy. We measured an energy low threshold of less than 4 keV with a 10 pF input capacitor and a minimal reachable sensitivity of the Equivalent Noise Charge (ENC) to input capacitance of less than 7 e-/pF obtained with a 6 mus peak time. IDeF-X ECLAIRs will be used for the readout of 6400 CdTe Schottky monopixel detectors of the 2D coded mask imaging telescope ECLAIRs aboard the SVOM satellite. IDeF-X ECLAIRs (or IDeF-X V2) has also been designed for the readout of a pixelated CdTe detector in the miniature spectro-imager prototype Caliste 256 that is currently foreseen for the high energy detector module of the Simbol-X mission.

Studies of crystalline CdZnTe radiation detectors and polycrystalline thin film CdTe for X-ray imaging applications

International Nuclear Information System (INIS)

Ede, Anthony

2001-01-01

The development of a replacement to the conventional film based X-ray imaging technique is required for many reasons. One possible route for this is the use of a large area film of a suitable semiconductor overlaid on an amorphous silicon readout array. A suitable semiconductor exists in cadmium telluride and its tertiary alloy cadmium zinc telluride. In this thesis the spectroscopic characteristics of commercially available CZT X- and γ-radiation detectors are established. The electronic, optical, electro-optic, structural and compositional properties of these detectors are then investigated. The attained data is used to infer a greater understanding for the carrier transport in a CZT radiation detector following the interaction of a high energy photon. Following this a method used to fabricate large area films of CdTe on a commercial scale is described. This is cathodic electrodeposition from an aqueous electrolyte. The theory and experimental arrangement for this technique are described in detail with preliminary results from the fabricated films presented. Attention is then turned to the CdS/CdTe films that are produced commercially for the photovoltaic industry. In this case the crystalline nature, surface topography and optical properties are investigated. A conclusion examines the progress that has been made towards the development of a large area fiat panel digital imaging technique. (author)

Modelling the chemical behaviour of tellurium species in the reactor pressure vessel and the reactor cooling system under severe accident conditions

International Nuclear Information System (INIS)

Alonso, A.; Gonzalez, C.

1991-07-01

This state of the art report contains information on the behaviour of tellurium and its compounds in the reactor pressure vessel and the reactor coolant system under light water reactor severe accident conditions. To characterise tellurium behaviour, it is necessary the previous knowledge of the species of tellurium released from the core, and simultaneity of its release with that of other materials which can alter the transport, for instance, control rod and structural materials. Release and transport experiments have been reviewed along with the models implemented in the codes which are used in the international community: TRAPMELT, RAFT, VICTORIA and SOPHIE. From the experiments, it can be concluded that other species different to Te 2 , such as tin telluride and cesium telluride, may be released from the fuel. That is why they must be considered in the transport phenomena. There is also experimental evidence of the strong interaction of Te 2 with Inconel 600 and stainless steel of the pipe walls and structures, however this strong interaction is in competition with the interaction of tellurium with aerosols, which under severe accident conditions may represent an area greater than that of the primary system. It is for the absence of significant tellurium species in the transport models, and also for the interaction of tellurium with aerosols, for which some codes show the greatest deficiencies

Design of a real-time spectroscopic rotating compensator ellipsometer without systematic errors

Energy Technology Data Exchange (ETDEWEB)

Broch, Laurent, E-mail: laurent.broch@univ-lorraine.fr [Laboratoire de Chimie Physique-Approche Multi-echelle des Milieux Complexes (LCP-A2MC, EA 4632), Universite de Lorraine, 1 boulevard Arago CP 87811, F-57078 Metz Cedex 3 (France); Stein, Nicolas [Institut Jean Lamour, Universite de Lorraine, UMR 7198 CNRS, 1 boulevard Arago CP 87811, F-57078 Metz Cedex 3 (France); Zimmer, Alexandre [Laboratoire Interdisciplinaire Carnot de Bourgogne, UMR 6303 CNRS, Universite de Bourgogne, 9 avenue Alain Savary BP 47870, F-21078 Dijon Cedex (France); Battie, Yann; Naciri, Aotmane En [Laboratoire de Chimie Physique-Approche Multi-echelle des Milieux Complexes (LCP-A2MC, EA 4632), Universite de Lorraine, 1 boulevard Arago CP 87811, F-57078 Metz Cedex 3 (France)

2014-11-28

We describe a spectroscopic ellipsometer in the visible domain (400–800 nm) based on a rotating compensator technology using two detectors. The classical analyzer is replaced by a fixed Rochon birefringent beamsplitter which splits the incidence light wave into two perpendicularly polarized waves, one oriented at + 45° and the other one at − 45° according to the plane of incidence. Both emergent optical signals are analyzed by two identical CCD detectors which are synchronized by an optical encoder fixed on the shaft of the step-by-step motor of the compensator. The final spectrum is the result of the two averaged Ψ and Δ spectra acquired by both detectors. We show that Ψ and Δ spectra are acquired without systematic errors on a spectral range fixed from 400 to 800 nm. The acquisition time can be adjusted down to 25 ms. The setup was validated by monitoring the first steps of bismuth telluride film electrocrystallization. The results exhibit that induced experimental growth parameters, such as film thickness and volumic fraction of deposited material can be extracted with a better trueness. - Highlights: • High-speed rotating compensator ellipsometer equipped with 2 detectors. • Ellipsometric angles without systematic errors • In-situ monitoring of electrocrystallization of bismuth telluride thin layer • High-accuracy of fitted physical parameters.

Capping biological quantum dots with the peptide CLPFFD to increase stability and to reduce effects on cell viability

Energy Technology Data Exchange (ETDEWEB)

Riveros, A. L., E-mail: ariveros@postqyf.uchile.cl [Universidad de Chile, Facultad de Ciencias Químicas y Farmacéuticas (Chile); Astudillo, J., E-mail: jason.astudillo@usach.cl; Vásquez, C. C., E-mail: claudio.vasquez@usach.cl [Universidad de Santiago de Chile, Facultad de Química y Biología (Chile); Jara, Danilo H., E-mail: Danilo.H.JaraQuinteros.1@nd.edu [University of Notre Dame, Radiation Laboratory, Department of Chemistry and Biochemistry (United States); Guerrero, Ariel R. [Universidad de Chile, Facultad de Ciencias Químicas y Farmacéuticas (Chile); Guzman, F., E-mail: fanny.guzman@ucv.cl [Pontificia Universidad Católica de Valparaíso, Núcleo de Biotecnología Curauma (Chile); Osorio-Roman, I. O., E-mail: igor.orlando@gmail.com [University of Windsor, Department of Chemistry and Biochemistry (Canada); Kogan, M. J., E-mail: mkogan@ciq.uchile.cl [Universidad de Chile, Facultad de Ciencias Químicas y Farmacéuticas (Chile)

2016-08-15

Highly fluorescent nanoparticles, or quantum dots, have multiple applications in biology and biomedicine; however, in most cases, it is necessary to functionalize them to enhance their biocompatibility and selectivity. Generally, functionalization is performed after nanoparticle synthesis and involves the use of molecules or macromolecules having two important traits: specific biological activity and functional groups that facilitate nanoparticle capping (i.e. atom–atom interaction). For this reason, we carried out a simple protocol for the chemical synthesis of cadmium telluride quantum dots capped with glutathione, and we then functionalized these nanoparticles with the amphipathic peptide CLPFFD. This peptide attaches selectively to β-Amyloid fibres, which are involved in Alzheimer’s disease. Our results show that the optical properties of the quantum dots are not affected by functionalization with this peptide. Infrared spectra showed that cadmium telluride quantum dots were functionalized with the peptide CLPFFD. In addition, no significant differences were observed between the surface charge of the quantum dots with or without CLPFFD and the nanocrystal size calculated for HR-TEM was 4.2 nm. Finally, our results show that quantum dots with CLPFFD are stable and that they resulted in a significantly reduced cytotoxicity with respect to that induced by quantum dots not conjugated with the peptide. Moreover, the results show that the CLPFFD-functionalized nanoparticles bind to β-Amyloid fibres.

Thermoelectric Generators for Automotive Waste Heat Recovery Systems Part I: Numerical Modeling and Baseline Model Analysis

Science.gov (United States)

Kumar, Sumeet; Heister, Stephen D.; Xu, Xianfan; Salvador, James R.; Meisner, Gregory P.

2013-04-01

A numerical model has been developed to simulate coupled thermal and electrical energy transfer processes in a thermoelectric generator (TEG) designed for automotive waste heat recovery systems. This model is capable of computing the overall heat transferred, the electrical power output, and the associated pressure drop for given inlet conditions of the exhaust gas and the available TEG volume. Multiple-filled skutterudites and conventional bismuth telluride are considered for thermoelectric modules (TEMs) for conversion of waste heat from exhaust into usable electrical power. Heat transfer between the hot exhaust gas and the hot side of the TEMs is enhanced with the use of a plate-fin heat exchanger integrated within the TEG and using liquid coolant on the cold side. The TEG is discretized along the exhaust flow direction using a finite-volume method. Each control volume is modeled as a thermal resistance network which consists of integrated submodels including a heat exchanger and a thermoelectric device. The pressure drop along the TEG is calculated using standard pressure loss correlations and viscous drag models. The model is validated to preserve global energy balances and is applied to analyze a prototype TEG with data provided by General Motors. Detailed results are provided for local and global heat transfer and electric power generation. In the companion paper, the model is then applied to consider various TEG topologies using skutterudite and bismuth telluride TEMs.

A portable cadmium telluride multidetector probe for cardiac function monitoring

Energy Technology Data Exchange (ETDEWEB)

Arntz, Y.; Chambron, J.; Dumitresco, B.; Eclancher, B. E-mail: eclan@alsace.u-strasbg.fr; Prat, V

1999-06-01

A new nuclear stethoscope based on a matrix of small CdTe semiconductor detectors has been developed for studying the cardiac performance by gamma ventriculography at the equilibrium, in rest and stress conditions, in the early and recovery phases of the coronary disease and to follow the long-term therapy. The light-weight probe consists of an array of 64 detectors 5x5x2 mm grouped in 16 independent units in a lead shielded aluminum box including 16 preamplifiers. The probe is connected to an electronic box containing DC power supply, 16 channel amplifiers, discriminators and counters, two analog-triggering ECG channels, and interface to a PC. The left ventricle activity is, preferentially, detected by using a low-resolution matching convergent collimator. A physical evaluation of the probe has been performed, both with static tests and dynamically with a hydraulic home-built model of beating heart ventricle paced by a rhythm simulator. The sum of the 16 detectors activity provided a radiocardiogram (RCG) which well depicted the filling and ejection of the cardiac beats, allowing to compare the clinically relevant parameters of the cardiac performance, proportional variables of the stroke volume (SV), ejection fraction (EF) and ventricular flow-rate with the known absolute values programmed on the model. The portable system is now in operation for clinical assessment of cardiac patients.

A portable cadmium telluride multidetector probe for cardiac function monitoring

International Nuclear Information System (INIS)

Arntz, Y.; Chambron, J.; Dumitresco, B.; Eclancher, B.; Prat, V.

1999-01-01

A new nuclear stethoscope based on a matrix of small CdTe semiconductor detectors has been developed for studying the cardiac performance by gamma ventriculography at the equilibrium, in rest and stress conditions, in the early and recovery phases of the coronary disease and to follow the long-term therapy. The light-weight probe consists of an array of 64 detectors 5x5x2 mm grouped in 16 independent units in a lead shielded aluminum box including 16 preamplifiers. The probe is connected to an electronic box containing DC power supply, 16 channel amplifiers, discriminators and counters, two analog-triggering ECG channels, and interface to a PC. The left ventricle activity is, preferentially, detected by using a low-resolution matching convergent collimator. A physical evaluation of the probe has been performed, both with static tests and dynamically with a hydraulic home-built model of beating heart ventricle paced by a rhythm simulator. The sum of the 16 detectors activity provided a radiocardiogram (RCG) which well depicted the filling and ejection of the cardiac beats, allowing to compare the clinically relevant parameters of the cardiac performance, proportional variables of the stroke volume (SV), ejection fraction (EF) and ventricular flow-rate with the known absolute values programmed on the model. The portable system is now in operation for clinical assessment of cardiac patients

Thermoelectric enhancement at low temperature in nonstoichiometric lead-telluride compounds

International Nuclear Information System (INIS)

Wang Heng; Li Jingfeng; Kita, Takuji

2007-01-01

Pb 1.17 Te thermoelectric polycrystalline materials were fabricated by mechanical alloying (MA) and spark plasma sintering (SPS). The property measurement and microstructural characterization showed that the present material has special features different from traditional Pb 1+x Te ingots with secondary Pb phase. An attractive enhancement of the thermoelectric figure of merit ZT = 0.64 was obtained at 450 K, with a low thermal conductivity of 1.11 W m -1 K -1 at this temperature. Transmission electron microscopy observation showed the existence of randomly dispersed nano features that are responsible for such enhancement, some of which are similar to the nanostructures reported in the AgPb m SbTe m+2 system. The origin of these regions is discussed and their influence on thermal conductivity is revealed. The results confirm the effectiveness of such a kind of nano feature in improving thermoelectric properties, especially in reducing thermal conductivity. They also indicate a new way of obtaining thermoelectric materials with such a kind of nano feature via MA and SPS

Next Generation Semiconductor-Based Radiation Detectors Using Cadmium Magnesium Telluride

Energy Technology Data Exchange (ETDEWEB)

Trivedi, Sudhir B [Brimrose Technology Corporation, Sparks Glencoe, MD (United States); Kutcher, Susan W [Brimrose Technology Corporation, Sparks Glencoe, MD (United States); Palsoz, Witold [Brimrose Technology Corporation, Sparks Glencoe, MD (United States); Berding, Martha [SRI International, Menlo Park, CA (United States); Burger, Arnold [Brimrose Technology Corporation, Sparks Glencoe, MD (United States)

2014-11-17

The primary objective of Phase I was to perform extensive studies on the purification, crystal growth and annealing procedures of CdMgTe to gain a clear understanding of the basic material properties to enable production of detector material with performance comparable to that of CdZnTe. Brimrose utilized prior experience in the growth and processing of II-VI crystals and produced high purity material and good quality single crystals of CdMgTe. Processing techniques for these crystals including annealing, mechanical and chemical polishing, surface passivation and electrode fabrication were developed. Techniques to characterize pertinent electronic characteristics were developed and gamma ray detectors were fabricated. Feasibility of the development of comprehensive defect modeling in this new class of material was demonstrated by our partner research institute SRI International, to compliment the experimental work. We successfully produced a CdMgTe detector that showed 662 keV gamma response with energy resolution of 3.4% (FWHM) at room temperature, without any additional signal correction. These results are comparable to existing CdZnTe (CZT) technology using the same detector size and testing conditions. We have successfully demonstrated detection of gamma-radiation from various isotopes/sources, using CdMgTe thus clearly proving the feasibility that CdMgTe is an excellent, low-cost alternative to CdZnTe.

A portable cadmium telluride multidetector probe for cardiac function monitoring

CERN Document Server

Arntz, Y; Dumitresco, B; Eclancher, B; Prat, V

1999-01-01

A new nuclear stethoscope based on a matrix of small CdTe semiconductor detectors has been developed for studying the cardiac performance by gamma ventriculography at the equilibrium, in rest and stress conditions, in the early and recovery phases of the coronary disease and to follow the long-term therapy. The light-weight probe consists of an array of 64 detectors 5x5x2 mm grouped in 16 independent units in a lead shielded aluminum box including 16 preamplifiers. The probe is connected to an electronic box containing DC power supply, 16 channel amplifiers, discriminators and counters, two analog-triggering ECG channels, and interface to a PC. The left ventricle activity is, preferentially, detected by using a low-resolution matching convergent collimator. A physical evaluation of the probe has been performed, both with static tests and dynamically with a hydraulic home-built model of beating heart ventricle paced by a rhythm simulator. The sum of the 16 detectors activity provided a radiocardiogram (RCG) wh...

Cadmium telluride leaching behavior: Discussion of Zeng et al. (2015).

Science.gov (United States)

Sinha, Parikhit

2015-11-01

Zeng et al. (2015) evaluate the leaching behavior and surface chemistry of II-VI semiconductor materials, CdTe and CdSe, in response to pH and O2. Under agitation in acidic and aerobic conditions, the authors found approximately 3.6%-6.4% (w/w) solubility of Cd content in CdTe in the Toxicity Characteristic Leaching Procedure (TCLP), Waste Extraction Test (WET), and dissolution test, with lower solubility (0.56-0.58%) under agitation in acidic and anoxic conditions. This range is comparable with prior long-term transformation and dissolution testing and bio-elution testing of CdTe (2.3%-4.1% w/w solubility of Cd content in CdTe). The implications for potential leaching behavior of CdTe-containing devices require further data. Since CdTe PV modules contain approximately 0.05% Cd content by mass, the starting Cd content in the evaluation of CdTe-containing devices would be lower by three orders of magnitude than the starting Cd content in the authors' study, and leaching potential would be further limited by the monolithic glass-adhesive laminate-glass structure of the device that encapsulates the semiconductor material. Experimental evaluation of leaching potential of CdTe PV modules crushed by landfill compactor has been conducted, with results of TCLP and WET tests on the crushed material below regulatory limits for Cd. CdTe PV recycling technology has been in commercial operation since 2005 with high yields for semiconductor (95%) and glass (90%) recovery. Copyright © 2015 Elsevier Ltd. All rights reserved.

Measurements of Thermal Emittance for Cesium Telluride Photocathodes at PITZ

CERN Document Server

Miltchev, V; Grabosch, H J; Han, J H; Krasilnikov, M; Oppelt, A; Petrosian, B; Staykov, L; Stephan, F

2005-01-01

The thermal emittance determines the lower emittance limit and its measurement is of high importance to understand the ultimate injector performance. In this contribution we present results of thermal emittance measurements under rf operation conditions for various Cs2Te cathodes and different accelerating gradients. Measurements of thermal emittance scaling with the cathode laser spot size are presented and analysed. The significance of the Schottky effect in the emittance formation process is discussed.

Low ohmic multilayer contacts in lead-tin-telluride diode lasers

International Nuclear Information System (INIS)

Herrmann, K.; Sumpf, B.; Boehme, D.; Hannemann, M.

1983-01-01

The preparation and the influence of low ohmic multilayer thin film contacts of lead-salt homo- and heterolasers on the degradation of lasing parameters during recycling processes between low working temperatures and room temperatures storage are described and discussed in detail. (author)

Study and microscopic characterization of the cadmium telluride deep levels

International Nuclear Information System (INIS)

Biglari, B.

1989-05-01

The spectroscopic methods PICTS, QTS and CTS were developed and perfected to investigate deep level analysis of high resistivity CdTe crystals which were either undoped, or doped with chlorine and copper. Crystals which were grown in space were also investigated. The main characterization of defect levels was determined and different correlations were established between the material's resistivity, chemical residues, dopant concentration and the nuclear radiation detector parameters. Using PICTS and CTS techniques, the generation of defects, under strong gamma-ray irradiation and particle bombardment was also studied. The influence of hydrogen on the main electrical characteristics of CdTe, in particular its ability to passivate the electrical activity of many deep defect and impurity states have been demonstrated. The compensation effects of Cl, Cu and H + are interpreted using the qualitative models based on different possibilities of pairing or triplet formation between the ions of these dopants and those of defects [fr

Surface Treatment And Protection Method For Cadium Zinc Telluride Crystals

Science.gov (United States)

Wright, Gomez W.; James, Ralph B.; Burger, Arnold; Chinn, Douglas A.

2006-02-21

A method for treatment of the surface of a CdZnTe (CZT) crystal that provides a native dielectric coating to reduce surface leakage currents and thereby, improve the resolution of instruments incorporating detectors using CZT crystals. A two step process is disclosed, etching the surface of a CZT crystal with a solution of the conventional bromine/methanol etch treatment, and after attachment of electrical contacts, passivating the CZT crystal surface with a solution of 10 w/o NH4F and 10 w/o H2O2 in water.

Impurity-induced photoconductivity of narrow-gap Cadmium–Mercury–Telluride structures

Energy Technology Data Exchange (ETDEWEB)

Kozlov, D. V., E-mail: dvkoz@impras.ru; Rumyantsev, V. V.; Morozov, S. V.; Kadykov, A. M. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Varavin, V. S.; Mikhailov, N. N.; Dvorestky, S. A. [Russian Academy of Sciences, Rzhanov Institute of Semiconductor Physics, Siberian Branch (Russian Federation); Gavrilenko, V. I. [Russian Academy of Sciences, Institute for Physics of Microstructures (Russian Federation); Teppe, F. [Universite Montpellier II, Laboratoire Charles Coulomb (L2C) (France)

2015-12-15

The photoconductivity (PC) spectra of CdHgTe (MCT) solid solutions with a Cd fraction of 17 and 19% are measured. A simple model for calculating the states of doubly charged acceptors in MCT solid solutions, which makes it possible to describe satisfactorily the observed photoconductivity spectra, is proposed. The found lines in the photoconductivity spectra of narrow-gap MCT structures are associated with transitions between the states of both charged and neutral acceptor centers.

Microscopic nature of inhomogeneous line broadening: Analysis of the excitation-line-narrowing spectra of Cf4+ in CeF4

International Nuclear Information System (INIS)

Liu, G.K.; Huang, J.; Beitz, J.V.

1993-01-01

Optical transitions between 5f states of tetravalent californium ion doped (1 metal-atom %) into CeF 4 exhibit unusually large inhomogeneous broadening. The nature of the inhomogeneous broadening in this system has been studied by using fluorescence line narrowing and excitation line narrowing (ELN). It is shown that the energy distributions of different electronic states of Cf 4+ in this system are correlated. In the ELN experiments, reduced excitation linewidth was obtained when selectively monitoring fluorescence emission. A linear relation was observed between the excitation energies of crystal-field states of the 5 G 4' manifold and the fluorescence wavelength monitored across the inhomogeneous profile of a 5 G 6' -- 7 F 6' transition. Analysis of these results by means of a microscopic theory proposed by Laird and Skinner [J. Chem. Phys. 90, 3880 (1989)] has provided insights into the structural properties of this disordered system

Chelation and stabilization of berkelium in oxidation state +IV

Science.gov (United States)

Deblonde, Gauthier J.-P.; Sturzbecher-Hoehne, Manuel; Rupert, Peter B.; An, Dahlia D.; Illy, Marie-Claire; Ralston, Corie Y.; Brabec, Jiri; de Jong, Wibe A.; Strong, Roland K.; Abergel, Rebecca J.

2017-09-01

Berkelium (Bk) has been predicted to be the only transplutonium element able to exhibit both +III and +IV oxidation states in solution, but evidence of a stable oxidized Bk chelate has so far remained elusive. Here we describe the stabilization of the heaviest 4+ ion of the periodic table, under mild aqueous conditions, using a siderophore derivative. The resulting Bk(IV) complex exhibits luminescence via sensitization through an intramolecular antenna effect. This neutral Bk(IV) coordination compound is not sequestered by the protein siderocalin—a mammalian metal transporter—in contrast to the negatively charged species obtained with neighbouring trivalent actinides americium, curium and californium (Cf). The corresponding Cf(III)-ligand-protein ternary adduct was characterized by X-ray diffraction analysis. Combined with theoretical predictions, these data add significant insight to the field of transplutonium chemistry, and may lead to innovative Bk separation and purification processes.

Operation manual for the INEL on-line mass-separator facility

International Nuclear Information System (INIS)

Anderl, R.A.

1984-06-01

This report is an operation manual for an on-line mass-separator facility which is located in Building 661 at the Test Reactor Area of the Idaho National Engineering Laboratory. The facility provides mass-separated sources of short-lived fission-product radionuclides whose decay properties can be studied using a variety of nuclear spectroscopic techniques. This facility is unique in that it utilizes the gas-jet technique to transport fission products from a 252 Cf source located in a hot cell to the ion source of the mass separator. This document includes the following: (a) a detailed description of the facility, (b) identification of equipment hazards and safety controls, (c) detailed operating procedures for startup, continuous operation and shutdown, (d) operating procedures for the californium hot cell, and (e) an operator's manual for the automated moving tape collector/data acquisition system. 7 references, 16 figures, 8 tables

Measurements of the neutron capture cross sections and incineration potentials of minor-actinides in high thermal neutron fluxes: Impact on the transmutation of nuclear wastes; Mesures des sections efficaces de capture et potentiels d'incineration des actinides mineurs dans les hauts flux de neutrons: Impact sur la transmutation des dechets

Energy Technology Data Exchange (ETDEWEB)

Bringer, O

2007-10-15

This thesis comes within the framework of minor-actinide nuclear transmutation studies. First of all, we have evaluated the impact of minor actinide nuclear data uncertainties within the cases of {sup 241}Am and {sup 237}Np incineration in three different reactor spectra: EFR (fast), GT-MHR (epithermal) and HI-HWR (thermal). The nuclear parameters which give the highest uncertainties were thus highlighted. As a result of fact, we have tried to reduce data uncertainties, in the thermal energy region, for one part of them through experimental campaigns in the moderated high intensity neutron fluxes of ILL reactor (Grenoble). These measurements were focused onto the incineration and transmutation of the americium-241, the curium-244 and the californium-249 isotopes. Finally, the values of 12 different cross sections and the {sup 241}Am isomeric branching ratio were precisely measured at thermal energy point. (author)

Operational safety at the radiometallurgy laboratory of Fontenay-aux-Roses

International Nuclear Information System (INIS)

Hayet, Lucien; Petit, Pierre; Conche, Roger.

1976-01-01

Opened in 1967, the Radiometallurgy Laboratory is responsible for the examination of plutonium 239 based nuclear fuels of breeder reactors such as Rapsodie and Phenix. Part of the same laboratory is also responsible for the manufacture of californium 252 sources. These neutron sources can have a neutron fluency yield of 2,3 10 10 n/s/4π (i.e. 10mg of 252cf). This large laboratory includes a total area of 117m 2 of hot surfaces. It also includes 14 high activity cells with a capacity of 100000Ci at 1MeV. Located only 7km from the center of Paris, it must incorporate a special design and a particularly sure safety policy. Several statistics are given: irradiations, contaminations, incidents, quantity of fissile material, solid and liquid wastes etc... The principles of safety management are outlined and an analysis given of this basic nuclear facility [fr

Bursting Smoke as an Infrared Countermeasure

OpenAIRE

Amarjit Singh; P. J. Kamale; S. A. Joshi; L. K. Bankar

1998-01-01

This paper describes the experimental setup for the evaluation of bursting smoke for anti-infrared role using SR-5000 spectroradiometer and a source of IR radiation (8-13 micrometer) using cadmium-mercury-telluride (CMI) detector cooled by liquid nitrogen. The particle size and shape of the powders used in the bursting smokes were determined microscopically using Carl Zeiss Jena Neophot- 21. Highest attenuation of 97 -lOO percent was produced for about 12 s using a mixture of bronze fl...

Tellurium: providing a bright future for solar energy

Science.gov (United States)

Goldfarb, Richard J.

2015-01-01

Tellurium is one of the least common elements on Earth. Most rocks contain an average of about 3 parts per billion tellurium, making it rarer than the rare earth elements and eight times less abundant than gold. Grains of native tellurium appear in rocks as a brittle, silvery-white material, but tellurium more commonly occurs in telluride minerals that include varied quantities of gold, silver, or platinum. Tellurium is a metalloid, meaning it possesses the properties of both metals and nonmetals.

Study of CdTe surface by SIMS and RBS ellipsometry

International Nuclear Information System (INIS)

Stuck, R.; Hage-Ali, M.; Grob, A.; Siffert, P.

1978-01-01

For a better understanding of the mechanisms involved in the rectification of metal-cadmium telluride contacts, the surface of bromine-methanol etched CdTe crystals by means of ellipsometry, secondary ions mass spectroscopy (SIMS) and Rutherford backscattering of charged particles (RBS) has been investigated. The results show that these surfaces are contaminated with bromine and that a tellurium surface oxide layer grows, its thickness increasing with time. This surface layer composition has been analyzed at different steps of its evolution [fr

Gamma motes for detection of radioactive materials in shipping containers

International Nuclear Information System (INIS)

Harold McHugh; William Quam; Stephan Weeks; Brendan Sever

2007-01-01

Shipping containers can be effectively monitored for radiological materials using gamma (and neutron) motes in distributed mesh networks. The mote platform is ideal for collecting data for integration into operational management systems required for efficiently and transparently monitoring international trade. Significant reductions in size and power requirements have been achieved for room-temperature cadmium zinc telluride (CZT) gamma detectors. Miniaturization of radio modules and microcontroller units are paving the way for low-power, deeply-embedded, wireless sensor distributed mesh networks

Multiplicity and correlated energy of gamma rays emitted in the spontaneous fission of Californium-252

International Nuclear Information System (INIS)

Brunson, G.S. Jr.

1982-06-01

An array of eight high-speed plastic scintillation detectors has been used to infer a mathematical model for the emission multipliciy of prompt gammas in the spontaneous fission of 252 Cf. Exceptional time resolution and coincidence capability permitted the separation of gammas from fast neutrons over a flight path of approximately 10 cm. About 20 different distribution models were tested. The average energy of the prompt gammas is inversely related to the number emitted; however, this inverse relationship is not strong and the total gamma energy does increase with increasing gamma number. An extension of the experiment incorporated a lithium-drifted germanium gamma spectrometer that resolved nearly 100 discrete gammas associated with fission. Of these gammas, some were preferentially associated with fission in which few gammas were emitted. Certain others were more frequent when many gammas were emitted. Results are presented

Remarkably High Stability of Late Actinide Dioxide Cations: Extending Chemistry to Pentavalent Berkelium and Californium.

Science.gov (United States)

Dau, Phuong D; Vasiliu, Monica; Peterson, Kirk A; Dixon, David A; Gibson, John K

2017-12-06

Actinyl chemistry is extended beyond Cm to BkO 2 + and CfO 2 + through transfer of an O atom from NO 2 to BkO + or CfO + , establishing a surprisingly high lower limit of 73 kcal mol -1 for the dissociation energies, D[O-(BkO + )] and D[O-(CfO + )]. CCSD(T) computations are in accord with the observed reactions, and characterize the newly observed dioxide ions as linear pentavalent actinyls; these being the first Bk and Cf species with oxidation states above IV. Computations of actinide dioxide cations AnO 2 + for An=Pa to Lr reveal an unexpected minimum for D[O-(CmO + )]. For CmO 2 + , and AnO 2 + beyond EsO 2 + , the most stable structure has side-on bonded η 2 -(O 2 ), as An III peroxides for An=Cm and Lr, and as An II superoxides for An=Fm, Md, and No. It is predicted that the most stable structure of EsO 2 + is linear [O=Es V =O] + , einsteinyl, and that FmO 2 + and MdO 2 + , like CmO 2 + , also have actinyl(V) structures as local energy minima. The results expand actinide oxidation state chemistry, the realm of the distinctive actinyl moiety, and the non-periodic character towards the end of the periodic table. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

Neutron Protection Factor Determination and Validation for a Vehicle Surrogate Using a Californium Fission Source

Science.gov (United States)

2017-06-01

study the laws governing shock wave propagation, and evaluate the suitability of military operations after being subjected to their use. During...14]. MCNP6.1 then outputs a dose spectrum, instead of the standard fluence spectrum created from the “ f4 ” tally [14]. In order to produce the dose...manually, an unmodified fluence tally ( f4 ) was exported externally to a spreadsheet. The energy bins were summed and grouped to mimic the energy bin

Thin-film solar cells

International Nuclear Information System (INIS)

Aberle, Armin G.

2009-01-01

The rapid progress that is being made with inorganic thin-film photovoltaic (PV) technologies, both in the laboratory and in industry, is reviewed. While amorphous silicon based PV modules have been around for more than 20 years, recent industrial developments include the first polycrystalline silicon thin-film solar cells on glass and the first tandem solar cells based on stacks of amorphous and microcrystalline silicon films ('micromorph cells'). Significant thin-film PV production levels are also being set up for cadmium telluride and copper indium diselenide.

Microstructured Optical Fiber for X-ray Detection

Science.gov (United States)

DeHaven, Stanton L.

2009-01-01

A novel scintillating optical fiber is presented using a composite micro-structured quartz optical fiber. Scintillating materials are introduced into the multiple inclusions of the fiber. This creates a composite optical fiber having quartz as a cladding with an organic scintillating material core. X-ray detection using these fibers is compared to a collimated cadmium telluride (CdTe) detector over an energy range from 10 to 40 keV. Results show a good correlation between the fiber count rate trend and that of the CdTe detector.

Recent developments in materials and detectors for the infrared; Proceedings of the Meeting, Cannes, France, November 25, 26, 1985

Science.gov (United States)

Morten, F. D. (Editor); Seeley, John S. (Editor)

1986-01-01

The present conference on advancements in IR-sensitive materials and detector technologies employing them gives attention to thermal detectors, focal plane array processing detectors, novel detector designs, general properties of IR optics materials, and preparation methods for such materials. Specific topics encompass the fabrication of InSb MIS structures prepared by photochemical vapor deposition, IR heterodyne detectors employing cadmium mercury telluride, low microphony pyroelectric arrays, IR detection based on minority carrier extrusion, longwave reststrahl in IR crystals, and molecular beam techniques for optical thin film fabrication.

Detector and sensor devices: fabrication from lead compounds. January 1975-September 1988 (Citations from the INSPEC: Information Services for the Physics and Engineering Communities data base). Report for January 1975-September 1988

International Nuclear Information System (INIS)

1988-10-01

This bibliography contains citations concerning developments, properties, and production of lead compound materials for use in detector- and sensor-device fabrication. Topics include infrared detectors, lead compound heterojunctions and photodiodes, photovoltaic and pyroelectric detectors, epitaxial growth methods, remote sensing, and night vision. Development and preparation of lead sulfide, selenide, telluride, and thallium-monoxide compounds are discussed. Performance analysis and applications of lead compound detectors and sensors are examined. (This updated bibliography contains 229 citations, 19 of which are new entries to the previous edition.)

The significance of chromosome deletions in atomic-bomb survivors

International Nuclear Information System (INIS)

Tanaka, Kimio; Shigeta, Chiharu; Oguma, Nobuo; Kamada, Nanao; Deng, Z.; Niimi, Masanobu; Aisaka, Tadaichi.

1986-01-01

In 39 A-bomb survivors 40 years after exposure at ≤ 1,000 m from ground zero, the frequency and features of chromosome deletions in peripheral lymphocytes were examined using a differential staining technique. Simultaneously, in vitro irradiation experiment with Cf-252 was made to infer chromosome aberrations occuring immediately after exposure. Californium-252 with 100 rad induced dicentric and ring chromosomes in 40 % of the cells and acentric fragments in 44 %. Among the A-bomb survivors, chromosome aberrations were observed in 651 (21 %) of the total 3,136 cells. There were 146 cells with deletions (22 % of abnormal cells; 5 % of the total cells), and 10 cells with acentric fragment (0.3 % of the total cells). The figure for deletions was far higher than that reported in the literature. A large number of deletions were seen in chromosomes no.4, no.21, and no.22, and a few deletions in chromosomes no.7 and no.20. Significance of chromosome deletions is discussed. (Namekawa, K.)

Cleanex process: a versatile solvent extraction process for recovery and purification of lanthanides, americium, and curium

International Nuclear Information System (INIS)

Bigelow, J.E.; Collins, E.D.; King, L.J.

1979-01-01

At a concentration of 1 M in straight-chain hydrocarbon diluent, HDEHP will extract americium, curium, and other trivalent actinide and lanthanide elements from dilute acid or salt solutions. The solute is back-extracted with more concentrated acid, either nitric or hydrochloric. The process has been used in the continuous, countercurrent mode, but its greatest advantage arises in batch extractions where the excess acid can be titrated with NaOH to produce a final acidity of about 0.03 M. Under these conditions, 99% recovery can be achieved, usually in one stage. Cleanex was used on the 50-liter scale at the Transuranium Processing Plant at Oak Ridge for 12 years to provide a broad spectrum cleanup to transuranium elements before applying more sophisticated techniques for separating individual products. The process is also used routinely to recover excessive losses of curium and/or californium from plant waste streams. The solvent system is relatively resistant to radiation damage, being usable up to 200 W-h/liter

Dynamic vortex dust structures in a nuclear-track plasma

International Nuclear Information System (INIS)

Rykov, V A; Khudyakov, A V; Filinov, V S; Vladimirov, V I; Deputatova, L V; Krutov, D V; Fortov, V E

2003-01-01

Results are presented from Monte Carlo calculations of the electric charge on dust grains in a plasma produced during the slowing down of radioactive decay products of californium nuclei in neon. The dust grain charging is explained as being due to the drift of electrons and ions in an external electric field. It is shown that the charges of the grains depend on their coordinates and strongly fluctuate with time. The time-averaged grain charges agree with the experimental data obtained on ordered liquid-like dust structures in a nuclear-track plasma. The time-averaged dust grain charges are used to carry out computer modelling of the formation of dynamic vortex structures observed in experiments. Evidence is obtained for the fact that the electrostatic forces experienced by the dust grains are potential in character. The paper is supplemented by a video clip showing the typical dynamics of the simulated vortex dust structure

Monitoring taconite process streams with thermal neutron capture-gamma ray analysis. Report of investigations/1980

International Nuclear Information System (INIS)

Woodbury, F.B.W.

1980-12-01

The Bureau of Mines is evaluating alternative technologies to treat oxidized taconites. Since process control is an essential element in the application of these process technologies, research was performed on a prototype monitoring system utilizing a californium-252 (252-Cf) neutron source and a thermal neutron capture-gamma ray spectra analysis method to measure the amount of iron and percent solids in process slurries. The prototype system was used to monitor the concentrate and tailing streams in a 900-lb/hr flotation pilot plant during continuous around-the-clock tests. The iron content of the process slurries was determined by measuring the total peak areas under the capture spectrum peaks at 7.626-7.632 MeV, the associated escape peaks at 7.136-7.122 and 6.626-6.612 MeV, and the iron doublets at 4.900 and 4.998 MeV. A potential method for determining the percent solids in process slurries using the 2.22 MeV hydrogen capture peak is discussed

A survey of uses and users of 252Cf

International Nuclear Information System (INIS)

Bigelow, J.E.; Alexander, C.W.; King, L.J.; Knauer, J.B.; Notz, K.J.

1989-01-01

Californium-252, which is one of the transuranium-element isotopes being produced in the Radiochemical Engineering Development Center (REDC) at Oak Ridge National Laboratory (ORNL), has found many applications in service to industry and medicine. As a neutron source, 252 Cf is unique in providing a highly concentrated and extremely reliable neutron spectrum from a very small assembly. Over the past 22 years, 252 Cf has been applied with great success to cancer therapy, to neutron radiography of objects ranging from flowers to entire aircraft, to startup sources for nuclear reactors, to fission activation assay for quality control and safeguards of all commercial nuclear fuel, and to many other beneficial uses, some of which are now poised for further growth. The extensive exploitation of this highly specialized product has been made possible through 252 Sales/Loan programs sponsored by the US DOE Office of Nuclear Materials Production, initially at the Savannah River Laboratory and now at ORNL

Reactor production of 252Cf and transcurium isotopes

International Nuclear Information System (INIS)

Alexander, C.W.; Halperin, J.; Walker, R.L.; Bigelow, J.E.

1990-01-01

Berkelium, californium, einsteinium, and fermium are currently produced in the High Flux Isotope Reactor (HFIR) and recovered in the Radiochemical Engineering Development Center (REDC) at the Oak Ridge National Laboratory (ORNL). All the isotopes are used for research. In addition, 252 Cf, 253 Es, and 255 Fm have been considered or are used for industrial or medical applications. ORNL is the sole producer of these transcurium isotopes in the western world. A wide range of actinide samples were irradiated in special test assemblies at the Fast Flux Test Facility (FFTF) at Hanford, Washington. The purpose of the experiments was to evaluate the usefulness of the two-group flux model for transmutations in the special assemblies with an eventual goal of determining the feasibility of producing macro amounts of transcurium isotopes in the FFTF. Preliminary results from the production of 254g Es from 252 Cf will be discussed. 14 refs., 5 tabs

Actinide metals

Energy Technology Data Exchange (ETDEWEB)

Brown, Paul L. [Geochem Australia, Kiama, NSW (Australia); Ekberg, Christian [Chalmers Univ. of Technology, Goeteborg (Sweden). Nuclear Chemistry/Industrial Materials Recycling

2016-07-01

All isotopes of actinium are radioactive and exist in aqueous solution only in the trivalent state. There have been very few studies on the hydrolytic reactions of actinium(III). The hydrolysis reactions for uranium would only be important in alkaline pH conditions. Thermodynamic parameters for the hydrolysis species of uranium(VI) and its oxide and hydroxide phases can be determined from the stability and solubility constants. The hydrolytic behaviour of neptunium(VI) is quite similar to that of uranium(VI). The solubility constant of NpO{sub 2}OH(am) has been reported a number of times for both zero ionic strength and in fixed ionic strength media. Americium can form four oxidation states in aqueous solution, namely trivalent, tetravalent, pentavalent and hexavalent. Desire, Hussonnois and Guillaumont determined stability constants for the species AmOH{sup 2+} for the actinides, plutonium(III), americium(III), curium(III), berkelium(III) and californium(III) using a solvent extraction technique.