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Sample records for inorganic-organic rubbery scintillators

  1. Inorganic-organic rubbery scintillators

    CERN Document Server

    Gektin, A V; Pogorelova, N; Neicheva, S; Sysoeva, E; Gavrilyuk, V

    2002-01-01

    Spectral-kinetic luminescence properties of films, containing homogeneously dispersed scintillation particles of CsI, CsI:Tl, CsI:Na, and NaI:Tl in optically transparent organosiloxane matrix, are presented. Material is flexible and rubbery and in consequence the detectors of convenient shapes can be produced. It is found that luminescence spectra of the received films are identical whereas decay times are much shorter compared to the same ones of the corresponding single crystals. Layers with pure CsI demonstrate only the fast UV emission (307 nm, 10 ns) without blue microsecond afterglow typical for crystals. The films containing NaI:Tl are non-hygroscopic and preserve scintillation properties for a long time in humid atmosphere unlike single crystals. Organosiloxane layers with CsI:Tl particles provide high light output with good energy resolution for sup 5 sup 5 Fe, sup 1 sup 0 sup 9 Cd, sup 2 sup 4 sup 1 Am sources, and are capable of detecting both X-rays and alpha-, beta-particles.

  2. Fundamental study of inorganic-organic hybrid scintillator using Pr:Lu.sub.3./sub.Al.sub.5./sub.O.sub.12./sub. and plastic scintillator

    Czech Academy of Sciences Publication Activity Database

    Kamada, K.; Kurosawa, S.; Yokota, Y.; Yanagida, T.; Nikl, Martin; Yoshikawa, A.

    2014-01-01

    Roč. 53, č. 4 (2014), "04EH10-1"-"04EH10-4" ISSN 0021-4922 Institutional support: RVO:68378271 Keywords : scintillators * Pr:LuAG * luminescence Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.127, year: 2014

  3. Scintillators

    International Nuclear Information System (INIS)

    Cusano, D.A.; Holub, F.F.; Prochazka, S.

    1979-01-01

    Scintillator bodies comprising phosphor materials and having high optical translucency with low light absorption, and methods of making the scintillator bodies, are described. Fabrication methods include (a) a hot-pressing process, (b) cold-pressing followed by sintering, (c) controlled cooling from a melt, and (d) hot-forging. The scintillator bodies that result are easily machined to desired shapes and sizes. Suitable phosphors include BaFCl:Eu, LaOBr:Tb, CsI:Tl, CaWO 4 and CdWO 4 . (U.K.)

  4. Apparatus Tests Peeling Of Bonded Rubbery Material

    Science.gov (United States)

    Crook, Russell A.; Graham, Robert

    1996-01-01

    Instrumented hydraulic constrained blister-peel apparatus obtains data on degree of bonding between specimen of rubbery material and rigid plate. Growth of blister tracked by video camera, digital clock, pressure transducer, and piston-displacement sensor. Cylinder pressure controlled by hydraulic actuator system. Linear variable-differential transformer (LVDT) and float provide second, independent measure of change in blister volume used as more precise volume feedback in low-growth-rate test.

  5. Inorganic-organic nanocomposites for optical coatings

    Science.gov (United States)

    Schmidt, Helmut K.; Krug, Herbert; Sepeur-Zeitz, Bernhard; Geiter, Elisabeth

    1997-10-01

    The fabrication of nanoparticles by the sol-gel process and their use in polymeric or sol-gel-derived inorganic-organic composite matrices opens up interesting possibilities for designing new optical materials. Two different routes have been chosen for preparing optical nanocomposites: The first is the so-called 'in situ route,' where the nanoparticles are synthesized in a liquid mixture from Zr-alkoxides in a polymerizable system and diffractive gratings were produced by embossing uncured film. The second is the 'separate' preparation route, where a sterically stabilized dry nanoboehmite powder was completely redispersed in an epoxy group-containing matrix and hard coatings with optical quality on polycarbonate were prepared.

  6. Inorganic-organic hybrid polymers for food packaging

    CSIR Research Space (South Africa)

    Kesavan Pillai, Sreejarani

    2015-09-01

    Full Text Available packaging application. Numerous hybrid inorganic-organic materials have been developed using low temperature sol-gel chemistry, which enables the tailoring of the nanostructure and the resulting material is often multifunctional, offering a wide range...

  7. Matrices for Sensors from Inorganic, Organic, and Biological Nanocomposites

    Directory of Open Access Journals (Sweden)

    Eugenia Pechkova

    2011-08-01

    Full Text Available Matrices and sensors resulting from inorganic, organic and biological nanocomposites are presented in this overview. The term nanocomposite designates a solid combination of a matrix and of nanodimensional phases differing in properties from the matrix due to dissimilarities in structure and chemistry. The nanoocomposites chosen for a wide variety of health and environment sensors consist of Anodic Porous Allumina and P450scc, Carbon nanotubes and Conductive Polymers, Langmuir Blodgett Films of Lipases, Laccases, Cytochromes and Rhodopsins, Three-dimensional Nanoporous Materials and Nucleic Acid Programmable Protein Arrays.

  8. Synthesis and characterization of rubbery epoxy/organoclay hectorite nanocomposites

    Directory of Open Access Journals (Sweden)

    2007-12-01

    Full Text Available The present research investigates the morphology, the mechanical, and the viscoelastic properties of rubbery epoxy/clay nanocomposites synthesized by in situ polymerisation of a prepolymer diglycidyl ether of bisphenol-A crosslinked with an aliphatic diamine based on a polyoxypropylene backbone. The inorganic phase was hectorite, exchanged with octadecylammonium ions in order to give organophilic properties to the phyllosilicate. An ultrasonicator was used to disperse the silicate clay layer into epoxy-amine matrix. The morphology of epoxy-hectorite nanocomposites examined by transmission electron microscopy (TEM showed that mixed delamination or intercalation or microdispersion could occur depending on type of organoclay. Moreover, the mechanical and viscoelastic properties were found to be improved with only the treated hectorite.

  9. Investigations of inorganic and hybrid inorganic-organic nanostructures

    Science.gov (United States)

    Kam, Kinson Chihang

    This thesis focuses on the exploratory synthesis and characterization of inorganic and hybrid inorganic-organic nanomaterials. In particular, nanostructures of semiconducting nitrides and oxides, and hybrid systems of nanowire-polymer composites and framework materials, are investigated. These materials are characterized by a variety of techniques for structure, composition, morphology, surface area, optical properties, and electrical properties. In the study of inorganic nanomaterials, gallium nitride (GaN), indium oxide (In2O3), and vanadium dioxide (VO2) nanostructures were synthesized using different strategies and their physical properties were examined. GaN nanostructures were obtained from various synthetic routes. Solid-state ammonolysis of metastable gamma-Ga2O 3 nanoparticles was found to be particularly successful; they achieved high surface areas and photoluminescent study showed a blue shift in emission as a result of surface and size defects. Similarly, In2O3 nanostructures were obtained by carbon-assisted solid-state syntheses. The sub-oxidic species, which are generated via a self-catalyzed vapor-liquid-solid mechanism, resulted in 1D nanostructures including nanowires, nanotrees, and nanobouquets upon oxidation. On the other hand, hydrothermal methods were used to obtain VO2 nanorods. After post-thermal treatment, infrared spectroscopy demonstrated that these nanorods exhibit a thermochromic transition with temperature that is higher by ˜10°C compared to the parent material. The thermochromic behavior indicated a semiconductor-to-metal transition associated with a structural transformation from monoclinic to rutile. The hybrid systems, on the other hand, enabled their properties to be tunable. In nanowire-polymer composites, zinc oxide (ZnO) and silver (Ag) nanowires were synthesized and incorporated into polyaniline (PANI) and polypyrrole (PPy) via in-situ and ex-situ polymerization method. The electrical properties of these composites are

  10. The enhancement of photoresponse of an ordered inorganic-organic hybrid architecture by increasing interfacial contacts

    International Nuclear Information System (INIS)

    Zhang Bin; Chen Xudong; Ma Shaohua; Yang Jin; Zhang Mingqiu; Chen Yujie

    2010-01-01

    A modified ZnO quantum dot/polythiophene (ZnO/PTh) inorganic-organic hybrid architecture was fabricated by using ordered mesoporous silica (SBA-15) as the retaining template. First, a two-step strategy was developed to synthesize an ordered organic conducting polymer composite (PTh/SBA-15). Then, ZnO quantum dots were in situ formed on the pore walls of the ordered PTh/SBA-15 composite. Photoresponse of the inorganic-organic hybrid was studied with respect to its incident photon to collected electron conversion efficiency (IPCE) and morphology. The presence of SBA-15 proved to be critical for controlling the interfacial morphology and hence enlarging the interfacial area of the inorganic-organic heterojunction. The proposed approach may act as a key method to open up potential applications in photovoltaic devices.

  11. The enhancement of photoresponse of an ordered inorganic-organic hybrid architecture by increasing interfacial contacts.

    Science.gov (United States)

    Zhang, Bin; Chen, Xudong; Ma, Shaohua; Chen, Yujie; Yang, Jin; Zhang, Mingqiu

    2010-02-10

    A modified ZnO quantum dot/polythiophene (ZnO/PTh) inorganic-organic hybrid architecture was fabricated by using ordered mesoporous silica (SBA-15) as the retaining template. First, a two-step strategy was developed to synthesize an ordered organic conducting polymer composite (PTh/SBA-15). Then, ZnO quantum dots were in situ formed on the pore walls of the ordered PTh/SBA-15 composite. Photoresponse of the inorganic-organic hybrid was studied with respect to its incident photon to collected electron conversion efficiency (IPCE) and morphology. The presence of SBA-15 proved to be critical for controlling the interfacial morphology and hence enlarging the interfacial area of the inorganic-organic heterojunction. The proposed approach may act as a key method to open up potential applications in photovoltaic devices.

  12. Polymer dynamics in rubbery epoxy networks/polyhedral oligomeric silsesquioxanes nanocomposites

    Czech Academy of Sciences Publication Activity Database

    Kourkoutsaki, T.; Logakis, E.; Kroutilová, Irena; Matějka, Libor; Nedbal, J.; Pissis, P.

    2009-01-01

    Roč. 113, č. 4 (2009), s. 2569-2582 ISSN 0021-8995 R&D Projects: GA AV ČR IAA400500701 Institutional research plan: CEZ:AV0Z40500505 Keywords : nanocomposites * dielectric properties * rubbery epoxy networks Subject RIV: CD - Macromolecular Chemistry Impact factor: 1.203, year: 2009

  13. Effect of Poisson's loss factor of rubbery material on underwater sound absorption of anechoic coatings

    Science.gov (United States)

    Zhong, Jie; Zhao, Honggang; Yang, Haibin; Yin, Jianfei; Wen, Jihong

    2018-06-01

    Rubbery coatings embedded with air cavities are commonly used on underwater structures to reduce reflection of incoming sound waves. In this paper, the relationships between Poisson's and modulus loss factors of rubbery materials are theoretically derived, the different effects of the tiny Poisson's loss factor on characterizing the loss factors of shear and longitudinal moduli are revealed. Given complex Young's modulus and dynamic Poisson's ratio, it is found that the shear loss factor has almost invisible variation with the Poisson's loss factor and is very close to the loss factor of Young's modulus, while the longitudinal loss factor almost linearly decreases with the increase of Poisson's loss factor. Then, a finite element (FE) model is used to investigate the effect of the tiny Poisson's loss factor, which is generally neglected in some FE models, on the underwater sound absorption of rubbery coatings. Results show that the tiny Poisson's loss factor has a significant effect on the sound absorption of homogeneous coatings within the concerned frequency range, while it has both frequency- and structure-dependent influence on the sound absorption of inhomogeneous coatings with embedded air cavities. Given the material parameters and cavity dimensions, more obvious effect can be observed for the rubbery coating with a larger lattice constant and/or a thicker cover layer.

  14. Final rubbery state characterization using a hollow cylinder dynamic shear sample on DMA7

    Directory of Open Access Journals (Sweden)

    Vilaiporn Luksameevanish

    2004-09-01

    Full Text Available Dynamic properties of raw natural rubber were examined using a hollow cylinder shaped samplesubjected to shear deformation on a laboratory Dynamic Mechanical Analyser. According to Cox-Merz’s study, dynamic complex viscosity obtained by this method showed a good agreement with shear flow viscosity measured by capillary rheometer. A master curve derived from the dynamic properties were then characterized. A crossing point of storage modulus (G’ and loss modulus (G’’ curves in the master curves was used to identify the final rubbery state, which indicated the transition of rubbery state and molten state. The position of this point depends on quantities and types of reinforcing or non-reinforcing fillers. The final rubbery state was shifted to higher frequency or lower temperature. It was found that the final rubbery state of CaCO3-filled rubber compounds was shifted to higher frequency or lower temperature by approximately 4 decades, while the translation of carbon black-filled rubber compounds was lower than unfilled rubber by about 1 decade. This phenomenon can be used to explain rubber elasticity, i.e. a decreasing of die swell of CaCO3 filled compounds at any high processing temperature. On the other hand, high magnitude of die swell for carbon black filled compound was still obtained.

  15. Inorganic-Organic Molecules and Solids with Nanometer-Sized Pores

    Energy Technology Data Exchange (ETDEWEB)

    Maverick, Andrew W

    2011-12-17

    We are constructing porous inorganic-organic hybrid molecules and solids, many of which contain coordinatively unsaturated metal centers. In this work, we use multifunctional ²-diketone ligands as building blocks to prepare extended-solid and molecular porous materials that are capable of reacting with a variety of guest molecules.

  16. Scintillator structures

    International Nuclear Information System (INIS)

    Cusano, D.A.; Prener, J.S.

    1978-01-01

    Distributed phosphor scintillator structures providing superior optical coupling to photoelectrically responsive devices together with methods for fabricating said scintillator structures are disclosed. In accordance with one embodiment of the invention relating to scintillator structures, the phosphor is distributed in a 'layered' fashion with certain layers being optically transparent so that the visible wavelength output of the scintillator is better directed to detecting devices. In accordance with another embodiment of the invention relating to scintillator structures, the phosphor is distributed throughout a transparent matrix in a continuous fashion whereby emitted light is more readily transmitted to a photodetector. Methods for fabricating said distributed phosphor scintillator structures are also disclosed. (Auth.)

  17. Scintillation scanner

    International Nuclear Information System (INIS)

    Mehrbrodt, A.W.; Mog, W.F.; Brunnett, C.J.

    1977-01-01

    A scintillation scanner having a visual image producing means coupled through a lost motion connection to the boom which supports the scintillation detector is described. The lost motion connection is adjustable to compensate for such delays as may occur between sensing and recording scintillations. 13 claims, 5 figures

  18. Inorganic-organic hybrid polymer for preparation of affiliating material using electron beam irradiation

    International Nuclear Information System (INIS)

    Chung, Jaeseung; Kim, Seongeun; Kim, Byounggak; Lee, Jongchan; Park, Jihyun; Lee, Byeongcheol

    2011-01-01

    Recently, silver nano materials have gained a lot of attentions in a variety of applications due to the unique biological, optical, and electrical properties. Especially, the antifouling property of these material is considered to be an important character for biomedical field, marine coatings industry, biosensor, and drug delivery. In this study, we design and synthesize the inorganic-organic hybrid polymer for preparation of affiliating materials. Silver nano materials having antifouling property with different shapes are prepared by control the electron beam irradiation conditions. Inorganic-organic hybrid polymer was synthesized and characterized. → Morphology and size controlled nano materials are prepared using electron beam irradiation. → Silver nano materials having various shapes can be used for antifouling material

  19. New polymer lithium secondary batteries based on ORMOCER (R) electrolytes-inorganic-organic polymers

    DEFF Research Database (Denmark)

    Popall, M.; Buestrich, R.; Semrau, G.

    2001-01-01

    Based on new plasticized inorganic-organic polymer electrolytes CM. Popall, M. Andrei, J. Kappel, J. Kron, K. Olma, B. Olsowski,'ORMOCERs as Inorganic-organic Electrolytes for New Solid State Lithium Batteries and Supercapacitors', Electrochim. Acta 43 (1998) 1155] new flexible foil-batteries...... electrolyte, typical for polymer electrolytes. Cycling tests (more than 900 cycles) proved that the unplasticized electrolyte can act as binder in composite cathodes of lithium secondary batteries [2]. Charge/discharge cycles of complete batteries like (Cu/active carbon/ORMOCER(R)/LiCoO2/Al) with an ORMOCER......(R) as separator electrolyte were measured. The voltage drop of these batteries is very similar to cells with standard liquid electrolytes and the efficiency is close to 100%. Cycling the batteries with a current density of 0.25 mA cm(-2) between the voltage limits of 3.1 and 4.1 V results in a charge...

  20. Superhydrophobic hybrid inorganic-organic thiol-ene surfaces fabricated via spray-deposition and photopolymerization.

    Science.gov (United States)

    Sparks, Bradley J; Hoff, Ethan F T; Xiong, Li; Goetz, James T; Patton, Derek L

    2013-03-13

    We report a simple and versatile method for the fabrication of superhydrophobic inorganic-organic thiol-ene coatings via sequential spray-deposition and photopolymerization under ambient conditions. The coatings are obtained by spray-deposition of UV-curable hybrid inorganic-organic thiol-ene resins consisting of pentaerythritol tetra(3-mercaptopropionate) (PETMP), triallyl isocyanurate (TTT), 2,4,6,8-tetramethyl-2,4,6,8-tetravinylcyclotetrasiloxane (TMTVSi), and hydrophobic fumed silica nanoparticles. The spray-deposition process and nanoparticle agglomeration/dispersion provide surfaces with hierarchical morphologies exhibiting both micro- and nanoscale roughness. The wetting behavior, dependent on the concentration of TMTVSi and hydrophobic silica nanoparticles, can be varied over a broad range to ultimately provide coatings with high static water contact angles (>150°), low contact angle hysteresis, and low roll off angles (spray-deposition and UV-cure process on a variety of substrate surfaces including glass, paper, stone, and cotton fabric.

  1. Improved, low cost inorganic-organic separators for rechargeable silver-zinc batteries

    Science.gov (United States)

    Sheibley, D. W.

    1979-01-01

    Several flexible, low-cost inorganic-organic separators with performance characteristics and cycle life equal to, or better than, the Lewis Research Center Astropower separator were developed. These new separators can be made on continuous-production equipment at about one-fourth the cost of the Astropower separator produced the same way. In test cells, these new separators demonstrate cycle life improvement, acceptable operating characteristics, and uniform current density. The various separator formulas, test cell construction, and data analysis are described.

  2. Polymerizable Ionic Liquid Crystals Comprising Polyoxometalate Clusters toward Inorganic-Organic Hybrid Solid Electrolytes

    Directory of Open Access Journals (Sweden)

    Takeru Ito

    2017-07-01

    Full Text Available Solid electrolytes are crucial materials for lithium-ion or fuel-cell battery technology due to their structural stability and easiness for handling. Emergence of high conductivity in solid electrolytes requires precise control of the composition and structure. A promising strategy toward highly-conductive solid electrolytes is employing a thermally-stable inorganic component and a structurally-flexible organic moiety to construct inorganic-organic hybrid materials. Ionic liquids as the organic component will be advantageous for the emergence of high conductivity, and polyoxometalate, such as heteropolyacids, are well-known as inorganic proton conductors. Here, newly-designed ionic liquid imidazolium cations, having a polymerizable methacryl group (denoted as MAImC1, were successfully hybridized with heteropolyanions of [PW12O40]3− (PW12 to form inorganic-organic hybrid monomers of MAImC1-PW12. The synthetic procedure of MAImC1-PW12 was a simple ion-exchange reaction, being generally applicable to several polyoxometalates, in principle. MAImC1-PW12 was obtained as single crystals, and its molecular and crystal structures were clearly revealed. Additionally, the hybrid monomer of MAImC1-PW12 was polymerized by a radical polymerization using AIBN as an initiator. Some of the resulting inorganic-organic hybrid polymers exhibited conductivity of 10−4 S·cm−1 order under humidified conditions at 313 K.

  3. Understanding ligand-centred photoluminescence through flexibility and bonding of anthraquinone inorganic-organic frameworks

    Energy Technology Data Exchange (ETDEWEB)

    Furman, Joshua D; Burwood, Ryan P; Tang, Min; Mikhailovsky, Alexander A; Cheetham, Anthony K [Cambridge; (UCSB)

    2011-11-17

    Five novel inorganic-organic framework compounds containing the organic chromophore ligand anthraquinone-2,3-dicarboxylic acid (abbreviated H2AQDC) and calcium (CaAQDC), zinc (ZnAQDC), cadmium (CdAQDC), manganese (MnAQDC), and nickel (NiAQDC), respectively, have been synthesized. The photoluminescence of these materials is only visible at low temperatures and this behaviour has been evaluated in terms of ligand rigidity. It is proposed that the 2,3 position bonding sites result in luminescence-quenching ligand motion, as supported by X-ray diffraction and temperature-dependent luminescence studies.

  4. Coal liquefaction in an inorganic-organic medium. [DOE patent application

    Science.gov (United States)

    Vermeulen, T.; Grens, E.A. II; Holten, R.R.

    Improved process for liquefaction of coal by contacting pulverized coal in an inorganic-organic medium solvent system containing a ZnCl/sub 2/ catalyst, a polar solvent with the structure RX where X is one of the elements O, N, S, or P, and R is hydrogen or a lower hydrocarbon radical; the solvent system can contain a hydrogen donor solvent (and must when RX is water) which is immiscible in the ZnCl/sub 2/ and is a hydroaromatic hydrocarbon selected from tetralin, dihydrophenanthrene, dihydroanthracene or a hydrogenated coal derived hydroaromatic hydrocarbon distillate fraction.

  5. Scintillation Counters

    Science.gov (United States)

    Bell, Zane W.

    Scintillators find wide use in radiation detection as the detecting medium for gamma/X-rays, and charged and neutral particles. Since the first notice in 1895 by Roentgen of the production of light by X-rays on a barium platinocyanide screen, and Thomas Edison's work over the following 2 years resulting in the discovery of calcium tungstate as a superior fluoroscopy screen, much research and experimentation have been undertaken to discover and elucidate the properties of new scintillators. Scintillators with high density and high atomic number are prized for the detection of gamma rays above 1 MeV; lower atomic number, lower-density materials find use for detecting beta particles and heavy charged particles; hydrogenous scintillators find use in fast-neutron detection; and boron-, lithium-, and gadolinium-containing scintillators are used for slow-neutron detection. This chapter provides the practitioner with an overview of the general characteristics of scintillators, including the variation of probability of interaction with density and atomic number, the characteristics of the light pulse, a list and characteristics of commonly available scintillators and their approximate cost, and recommendations regarding the choice of material for a few specific applications. This chapter does not pretend to present an exhaustive list of scintillators and applications.

  6. Synthesis and properties of imidazole-grafted hybrid inorganic-organic polymer membranes

    International Nuclear Information System (INIS)

    Li Siwen; Zhou Zhen; Liu Meilin; Li Wen; Ukai, Junzo; Hase, Kohei; Nakanishi, Masatsugu

    2006-01-01

    Imidazole rings were grafted on alkoxysilane with a simple nucleophilic substitute reaction to form hybrid inorganic-organic polymers with imidazole rings. Proton exchange membranes (PEM) based on these hybrid inorganic-organic polymers and H 3 PO 4 exhibit high proton conductivity and high thermal stability in an atmosphere of low relative humidity. The grafted imidazole rings improved the proton conductivity of the membranes in the high temperature range. It is found that the proton conductivities increase with H 3 PO 4 content and temperature, reaching 3.2 x 10 -3 S/cm at 110 deg. C in a dry atmosphere for a membrane with 1 mole of imidazole ring and 7 moles of H 3 PO 4 . The proton conductivity increases with relative humidity (RH) as well, reaching 4.3 x 10 -2 S/cm at 110 deg. C when the RH is increased to about 20%. Thermogravimetric analysis (TGA) indicates that these membranes are thermally stable up to 250 deg. C in dry air, implying that they have a good potential to be used as the membranes for high-temperature PEM fuel cells

  7. Scintillation camera

    International Nuclear Information System (INIS)

    Zioni, J.; Klein, Y.; Inbar, D.

    1975-01-01

    The scintillation camera is to make pictures of the density distribution of radiation fields created by the injection or administration radioactive medicaments into the body of the patient. It contains a scintillation crystal, several photomultipliers and computer circuits to obtain an analytical function at the exits of the photomultiplier which is dependent on the position of the scintillations at the time in the crystal. The scintillation crystal is flat and spatially corresponds to the production site of radiation. The photomultipliers form a pattern whose basic form consists of at least three photomultipliers. They are assigned to at least two crossing parallel series groups where a vertical running reference axis in the crystal plane belongs to each series group. The computer circuits are each assigned to a reference axis. Each series of a series group assigned to one of the reference axes in the computer circuit has an adder to produce a scintillation dependent series signal. Furthermore, the projection of the scintillation on this reference axis is calculated. A series signal is used for this which originates from a series chosen from two neighbouring photomultiplier series of this group. The scintillation must have appeared between these chosen series. They are termed as basic series. The photomultiplier can be arranged hexagonally or rectangularly. (GG/LH) [de

  8. Highly Sensitive and Very Stretchable Strain Sensor Based on a Rubbery Semiconductor.

    Science.gov (United States)

    Kim, Hae-Jin; Thukral, Anish; Yu, Cunjiang

    2018-02-07

    There is a growing interest in developing stretchable strain sensors to quantify the large mechanical deformation and strain associated with the activities for a wide range of species, such as humans, machines, and robots. Here, we report a novel stretchable strain sensor entirely in a rubber format by using a solution-processed rubbery semiconductor as the sensing material to achieve high sensitivity, large mechanical strain tolerance, and hysteresis-less and highly linear responses. Specifically, the rubbery semiconductor exploits π-π stacked poly(3-hexylthiophene-2,5-diyl) nanofibrils (P3HT-NFs) percolated in silicone elastomer of poly(dimethylsiloxane) to yield semiconducting nanocomposite with a large mechanical stretchability, although P3HT is a well-known nonstretchable semiconductor. The fabricated strain sensors exhibit reliable and reversible sensing capability, high gauge factor (gauge factor = 32), high linearity (R 2 > 0.996), and low hysteresis (degree of hysteresis wearable smart gloves. Systematic investigations in the materials design and synthesis, sensor fabrication and characterization, and mechanical analysis reveal the key fundamental and application aspects of the highly sensitive and very stretchable strain sensors entirely from rubbers.

  9. Tailoring rice flour structure by rubbery milling for improved gluten-free baked goods.

    Science.gov (United States)

    Brütsch, Linda; Tribolet, Liliane; Isabettini, Stéphane; Soltermann, Patrick; Baumann, Andreas; Windhab, Erich J

    2018-05-10

    Ever-growing demand for gluten-free products calls for the development of novel food processing techniques to widen the range of existing baked goods. Extensive research has been targeted towards recipe optimization, widely neglecting the tailoring potential of process-induced structuring of gluten-free raw materials. Herein, we address this shortcoming by demonstrating the potential of rubbery milling for the generation of structure and techno-functionality in breads obtained from a variety of rice flour types. Moisture and temperature induced state transitions during milling were exploited to tailor the physicochemical properties of the flour. Moisture addition during conditioning of the different rice varieties and milling in the rubbery state considerably decreased starch damage due to more gentle disintegration. The degree of starch damage dictated the water absorption capacity of the rice flour types. Flour types with reduced starch damage upon milling offered lower dough densities, yielding bread loafs with a higher volume and better appearance. The choice of rice variety enables fine-tuning of the final product quality by influencing the dough viscoelasticity, which defines the final loaf volume. Whole grain rice flour dramatically increased the loaf volume, whilst simultaneously offering nutritional benefits. Combining the proposed functionalised flour types with current and future advances in product recipes paves the way towards optimised gluten-free goods.

  10. Plastic scintillator

    International Nuclear Information System (INIS)

    Andreeshchev, E.A.; Kilin, S.F.; Kavyrzina, K.A.

    1978-01-01

    A plastic scintillator for ionizing radiation detectors with high time resolution is suggested. To decrease the scintillation pulse width and to maintain a high light yield, the 4 1 , 4 5 -dibromo-2 1 , 2 5 , 5 1 , 5 5 -tetramethyl-n-quinquiphenyl (Br 2 Me 4 Ph) in combination with n-terphenyl (Ph 3 ) or 2, 5-diphenyloxadiazol-1, 3, 4 (PPD) is used as a luminescent addition. Taking into consideration the results of a special study, it is shown, that the following ratio of ingradients is the optimum one: 3-4 mass% Ph 3 or 4-7 mas% PPD + 2-5 mass% Br 2 Me 4 Ph + + polymeric base. The suggested scintillator on the basis of polystyrene has the light yield of 0.23-0.26 arbitrary units and the scintillation pulse duration at half-height is 0.74-0.84 ns

  11. {pi}-{pi} Interactions and magnetic properties in a series of hybrid inorganic-organic crystals

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez, M.; Lemus-Santana, A.A. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Legaria, Instituto Politecnico Nacional, Mexico, D. F. (Mexico); Rodriguez-Hernandez, J. [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Legaria, Instituto Politecnico Nacional, Mexico, D. F. (Mexico); Instituto de Ciencia y Tecnologia de Materiales, Universidad de La Habana (Cuba); Knobel, M. [Instituto de Fisica ' Gleb Wataghin' , Universidade Estadual de Campinas, SP (Brazil); Reguera, E., E-mail: edilso.reguera@gmail.com [Centro de Investigacion en Ciencia Aplicada y Tecnologia Avanzada, Unidad Legaria, Instituto Politecnico Nacional, Mexico, D. F. (Mexico)

    2013-01-15

    The series of hybrid inorganic-organic solids T(Im){sub 2}[Ni(CN){sub 4}] with T=Fe, Co, Ni and Im=imidazole were prepared by soft chemical routes from aqueous solutions of the involved building units: imidazole, T{sup 2+} metal and the [Ni(CN){sub 4}]{sup 2-} anionic block. The obtained samples were characterized from infrared and UV-vis spectroscopies, and thermogravimetric, X-ray diffraction and magnetic measurements. Anhydrous solids which crystallize with a monoclinic unit cell, in the I2/a space group with four formula units per cell (Z=4) were obtained. Their crystal structure was solved ab initio from the recorded X-ray powder patterns and then refined by the Rietveld method. The metal T is found with octahedral coordination to four N ends of CN groups and two imidazole molecules while the inner Ni atom preserves its planar coordination. The system of layers remains stacked in an ordered 3D structure through dipole-dipole and {pi}-{pi} interactions between imidazole rings from neighboring layers. In this way, a pillared structure is achieved without requiring the coordination of both nitrogen atoms from imidazole ring. The recorded magnetic data indicate the occurrence of a predominant ferromagnetic interaction at low temperature for Co and Ni but not for Fe. Such magnetic ordering is more favorable for Ni with transition temperature of 14.67 K, which was ascribed to the relatively high polarizing power for this metal. Within the considered T metals, to nickel the highest electron-withdrawing ability corresponds and this leads to an increase for the metal-ligand electron clouds overlapping and to a stronger {pi}-{pi} attractive interaction, two factors that result into a higher magnetic ordering temperature. - Graphical Abstract: Magnetic ordering through the {pi}-{pi} interaction between the imidazole rings. Highlights: Black-Right-Pointing-Pointer Hybrid inorganic-organic solids. Black-Right-Pointing-Pointer Hybrid inorganic-organic molecular based

  12. Exponential dependence of potential barrier height on biased voltages of inorganic/organic static induction transistor

    International Nuclear Information System (INIS)

    Zhang Yong; Yang Jianhong; Cai Xueyuan; Wang Zaixing

    2010-01-01

    The exponential dependence of the potential barrier height φ c on the biased voltages of the inorganic/organic static induction transistor (SIT/OSIT) through a normalized approach in the low-current regime is presented. It shows a more accurate description than the linear expression of the potential barrier height. Through the verification of the numerical calculated and experimental results, the exponential dependence of φ c on the applied biases can be used to derive the I-V characteristics. For both SIT and OSIT, the calculated results, using the presented relationship, are agreeable with the experimental results. Compared to the previous linear relationship, the exponential description of φ c can contribute effectively to reduce the error between the theoretical and experimental results of the I-V characteristics. (semiconductor devices)

  13. Inorganic-Organic Coating via Molecular Layer Deposition Enables Long Life Sodium Metal Anode.

    Science.gov (United States)

    Zhao, Yang; Goncharova, Lyudmila V; Zhang, Qian; Kaghazchi, Payam; Sun, Qian; Lushington, Andrew; Wang, Biqiong; Li, Ruying; Sun, Xueliang

    2017-09-13

    Metallic Na anode is considered as a promising alternative candidate for Na ion batteries (NIBs) and Na metal batteries (NMBs) due to its high specific capacity, and low potential. However, the unstable solid electrolyte interphase layer caused by serious corrosion and reaction in electrolyte will lead to big challenges, including dendrite growth, low Coulombic efficiency and even safety issues. In this paper, we first demonstrate the inorganic-organic coating via advanced molecular layer deposition (alucone) as a protective layer for metallic Na anode. By protecting Na anode with controllable alucone layer, the dendrites and mossy Na formation have been effectively suppressed and the lifetime has been significantly improved. Moreover, the molecular layer deposition alucone coating shows better performances than the atomic layer deposition Al 2 O 3 coating. The novel design of molecular layer deposition protected Na metal anode may bring in new opportunities to the realization of the next-generation high energy-density NIBs and NMBs.

  14. Characterization of Electret Based on Inorganic-organic Nanocomposite Using Fluoropolymer and Silica Nanoparticles

    International Nuclear Information System (INIS)

    Suzuki, M; Shimokizaki, M; Takahashi, T; Aoyagi, S; Yoshikawa, Y

    2015-01-01

    An A novel electret based on inorganic-organic nano composite using fluoropolymer and silica nanoparticles was developed in this study. CYTOP® is used to fabricate the nanocomposite electret, which is one of fluoropolymer. Three kinds of silica nanoparticles dispersed in methyl ethyl ketone were employed. Each type of nanoparticles was mixed in the CYTOP or stuck between three layers of CYTOP. Then, negative charge was implanted by corona discharge method. The initial surface potential of the nanocomposite electret was higher than that of a control electret made of pure CYTOP. Additionally, time stability of those was also better than that of control electret. However, above mentioned properties of the mix-typed electret was worse than that of stuck-typed electret, because of discharging through aggregates composed of the nanoparticles. (paper)

  15. Hybrid inorganic/organic photonic crystal biochips for cancer biomarkers detection

    Science.gov (United States)

    Sinibaldi, Alberto; Danz, Norbert; Munzert, Peter; Michelotti, Francesco

    2018-06-01

    We report on hybrid inorganic/organic one-dimensional photonic crystal biochips sustaining Bloch surface waves. The biochips were used, together with an optical platform operating in a label-free and fluorescence configuration simultaneously, to detect the cancer biomarker Angiopoietin 2 in a protein base buffer. The hybrid photonic crystals embed in their geometry a thin functionalization poly-acrylic acid layer deposited by plasma polymerization, which is used to immobilize a monoclonal antibody for highly specific biological recognition. The fluorescence operation mode is described in detail, putting into evidence the role of field enhancement and localization at the photonic crystal surface in the shaping and intensification of the angular fluorescence pattern. In the fluorescence operation mode, the hybrid biochips can attain the limit of detection 6 ng/ml.

  16. Developing a Macroscopic Mechanistic Model for Low Molecular Weight Diffusion through Polymers in the Rubbery State

    DEFF Research Database (Denmark)

    Martinez-Lopez, Brais; Huguet, P.; Gontard, N.

    2016-01-01

    Raman microspectroscopy was used to determine the Fickian diffusivity of two families of low molecular weight molecules through amorphous polystyrene in the rubbery state. Different effects of the temperature on diffusivity for each of the families suggested that molecular mobility is controlled...... by both the volume and flexibility of the diffusing substance when the movement of polymer chains can generate stress induced deformation of molecules. The diffusing molecules were represented as Newtonian spring–bead systems, which allowed us to quantify their flexibility, in function of the vibration...... frequency of their bonds by reconstructing their theoretical spectra. Results showed that the use of molecular descriptors that take into account flexibility rather than the most stable conformation of the diffusing molecules may improve the description of the diffusion behavior caused by variations...

  17. Colour tuning in white hybrid inorganic/organic light-emitting diodes

    International Nuclear Information System (INIS)

    Bruckbauer, Jochen; Brasser, Catherine; Edwards, Paul R; Martin, Robert W; Findlay, Neil J; Skabara, Peter J; Wallis, David J

    2016-01-01

    White hybrid inorganic/organic light-emitting diodes (LEDs) were fabricated by combining a novel organic colour converter with a blue inorganic LED. An organic small molecule was specifically synthesised to act as down-converter. The characteristics of the white colour were controlled by changing the concentration of the organic molecule based on the BODIPY unit, which was embedded in a transparent matrix, and volume of the molecule and encapsulant mixture. The concentration has a critical effect on the conversion efficiency, i.e. how much of the absorbed blue light is converted into yellow light. With increasing concentration the conversion efficiency decreases. This quenching effect is due to aggregation of the organic molecule at higher concentrations. Increasing the deposited amount of the converter does not increase the yellow emission despite more blue light being absorbed. Degradation of the organic converter was also observed during a period of 15 months from LED fabrication. Angular-dependent measurements revealed slight deviation from a Lambertian profile for the blue and yellow emission peaks leading to a small change in ‘whiteness’ with emission angle. Warm white and cool white light with correlated colour temperatures of 2770 K and 7680 K, respectively, were achieved using different concentrations of the converter molecule. Although further work is needed to improve the lifetime and poor colour rendering, these hybrid LEDs show promising results as an alternative approach for generating white LEDs compared with phosphor-based white LEDs. (paper)

  18. Metal-inorganic-organic matrices as efficient sorbents for hydrogen storage.

    Science.gov (United States)

    Azzouz, Abdelkrim; Nousir, Saadia; Bouazizi, Nabil; Roy, René

    2015-03-01

    Stabilization of metal nanoparticles (MNPs) without re-aggregation is a major challenge. An unprecedented strategy is developed for achieving high dispersion of copper(0) or palladium(0) on montmorillonite-supported diethanolamine or thioglycerol. This results in novel metal-inorganic-organic matrices (MIOM) that readily capture hydrogen at ambient conditions, with easy release under air stream. Hydrogen retention appears to involve mainly physical interactions, slightly stronger on thioglycerol-based MIOM (S-MIOM). Thermal enhancement of desorption suggests also a contribution of chemical interactions. The increase of hydrogen uptake with prolonged contact times arises from diffusion hindrance, which appears to be beneficial by favoring hydrogen entrapment. Even with compact structures, MIOMs act as efficient sorbents with much higher efficiency factor (1.14-1.17 mmol H 2 m(-2)) than many other sophisticated adsorbents reported in the literature. This opens new prospects for hydrogen storage and potential applications in microfluidic hydrogenation reactions. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. Liquid scintillation solutions

    International Nuclear Information System (INIS)

    Long, E.C.

    1976-01-01

    The liquid scintillation solution described includes a mixture of: a liquid scintillation solvent, a primary scintillation solute, a secondary scintillation solute, a variety of appreciably different surfactants, and a dissolving and transparency agent. The dissolving and transparency agent is tetrahydrofuran, a cyclic ether. The scintillation solvent is toluene. The primary scintillation solute is PPO, and the secondary scintillation solute is dimethyl POPOP. The variety of appreciably different surfactants is composed of isooctylphenol-polyethoxyethanol and sodium dihexyl sulphosuccinate [fr

  20. Scintillating camera

    International Nuclear Information System (INIS)

    Vlasbloem, H.

    1976-01-01

    The invention relates to a scintillating camera and in particular to an apparatus for determining the position coordinates of a light pulse emitting point on the anode of an image intensifier tube which forms part of a scintillating camera, comprising at least three photomultipliers which are positioned to receive light emitted by the anode screen on their photocathodes, circuit means for processing the output voltages of the photomultipliers to derive voltages that are representative of the position coordinates; a pulse-height discriminator circuit adapted to be fed with the sum voltage of the output voltages of the photomultipliers for gating the output of the processing circuit when the amplitude of the sum voltage of the output voltages of the photomultipliers lies in a predetermined amplitude range, and means for compensating the distortion introduced in the image on the anode screen

  1. Scintillator structure

    International Nuclear Information System (INIS)

    Cusano, D.A.; Prener, J.S.

    1979-01-01

    A scintillator structure comprises at least one layer of transparent fused quartz with a phosphor coating on one or both sides adjacent to at least one transparent layer of epoxy resin which directs light from the phosphor to a detector. The phosphor layer may be formed from a powder optionally with a binder, a single crystal or a melt, or by evaporation or sintering. A plurality of multiple layers may be used or the structure tilted for greater absorption. The structure may be surrounded by another such structure optionally operating in cascade with the first. Many phosphors are specified. A scintillator structure comprises phosphor particles dispersed in epoxy resin or copoly imide-silicone and cast in a multi-compartment box with long sides transparent to X-rays and dividers opaque to X-rays. (UK)

  2. Scintillating fibres

    International Nuclear Information System (INIS)

    Nahnhauer, R.

    1990-01-01

    In the search for new detector techniques, scintillating fibre technology has already gained a firm foothold, and is a strong contender for the extreme experimental conditions of tomorrow's machines. Organized by a group from the Institute of High Energy Physics, Berlin-Zeuthen, a workshop held from 3-5 September in the nearby village of Blossin brought together experts from East and West, and from science and industry

  3. Scintillating fibres

    Energy Technology Data Exchange (ETDEWEB)

    Nahnhauer, R. [IHEP Zeuthen (Germany)

    1990-11-15

    In the search for new detector techniques, scintillating fibre technology has already gained a firm foothold, and is a strong contender for the extreme experimental conditions of tomorrow's machines. Organized by a group from the Institute of High Energy Physics, Berlin-Zeuthen, a workshop held from 3-5 September in the nearby village of Blossin brought together experts from East and West, and from science and industry.

  4. Non-hydrolytic sol-gel synthesis of epoxysilane-based inorganic-organic hybrid resins

    International Nuclear Information System (INIS)

    Jana, Sunirmal; Lim, Mi Ae; Baek, In Chan; Kim, Chang Hae; Seok, Sang Il

    2008-01-01

    A silica-based inorganic-organic hybrid resins (IOHR) were synthesized by non-hydrolytic sol-gel process from 3-glycidoxypropyltrimethoxysilane (GLYMO) and diphenylsilanediol (DPSD) at a fixed amount of (20 mol%) phenyltrimethoxysilane using barium hydroxide as a catalyst. The confirmation of condensation reaction in the IOHR was done by liquid state 29 Si NMR (Nuclear Magnetic Resonance) spectroscopy, measurement of viscosity as well as weight average molecular weight (W m ) of the IOHR. The W m of the IOHR was varied from 1091 to 2151, depending upon the DPSD content. Fourier transform infrared (FTIR) spectroscopic measurements were performed to investigate the details of vibrational absorption bands in the IOHR. It was seen that up to 50 mol% of DPSD there were no absorption peaks in the region of 3000-3600 cm -1 responsible for O-H groups and it reappeared at 60 mol% of DPSD due to some unreacted OH groups present in the resin. The IOHR at all the compositions was oily transparent liquid, miscible with various organic solvents like toluene, cyclohexanone, chloroform, tehrahydrofuran (THF), etc., and also commercial epoxy resins but immiscible with water. The color of the IOHR was pale yellow, which lightened with increasing DPSD content. The IOHR having 40-50 mol% of DPSD were storable. The refractive index at 632.8 nm of the resin films varied from 1.556 to 1.588, depending upon the resin composition. Physico-chemical properties such as the thermal stability, visible transparency, etc. after curing were investigated as a function of the chemical composition

  5. Inorganic, organic, and encapsulated minerals in vegetable meal based diets for Sparus aurata (Linnaeus, 1758

    Directory of Open Access Journals (Sweden)

    David Domínguez

    2017-10-01

    Full Text Available Substituting fishmeal (FM with vegetable meal (VM can markedly affect the mineral composition of feeds, and may require additional mineral supplementation. Their bioavailability and optimal supplementation levels depend also on the form of delivery of minerals. The aim of the study was to determine the effect of different delivery forms of three major trace elements (Zn, Mn and Se in a marine teleost. Gilthead sea bream juveniles of 22.5 g were fed a VM-based diet for 12 weeks that was either not supplemented with these minerals or supplemented with inorganic, organic, or encapsulated inorganic forms of minerals in triplicate and compared to a FM-based diet. Our results showed that mineral delivery form significantly affected the biochemical composition and morphology of posterior vertebrae. Supplementation of VM-based diets with inorganic forms of the target minerals significantly promoted growth, increased the vertebral weight and content of ash and Zn, enhanced bone mineralization and affected the vertebral shape. Conversely, encapsulation of inorganic minerals reduced fish growth and vertebral mineral content, whereas supplementation of organic minerals, enhanced bone osteogenesis by upregulating bone morphogenetic protein 2 (bmp2 gene and produced vertebrae with a larger length in relation to height. Furthermore, organic mineral forms of delivery downregulated the expression of oxidative stress related genes, such as Cu/Zn superoxide dismutase (Cu/Zn sod and glutathione peroxidase 1 (gpx-1, suggesting thus that dietary minerals supplemented in the organic form could be reasonably considered more effective than the inorganic and encapsulated forms of supply.

  6. Structural tunability and switchable exciton emission in inorganic-organic hybrids with mixed halides

    International Nuclear Information System (INIS)

    Ahmad, Shahab; Vijaya Prakash, G.; Baumberg, Jeremy J.

    2013-01-01

    Room-temperature tunable excitonic photoluminescence is demonstrated in alloy-tuned layered Inorganic-Organic (IO) hybrids, (C 12 H 25 NH 3 ) 2 PbI 4(1−y) Br 4y (y = 0 to 1). These perovskite IO hybrids adopt structures with alternating stacks of low-dimensional inorganic and organic layers, considered to be naturally self-assembled multiple quantum wells. These systems resemble stacked monolayer 2D semiconductors since no interlayer coupling exists. Thin films of IO hybrids exhibit sharp and strong photoluminescence (PL) at room-temperature due to stable excitons formed within the low-dimensional inorganic layers. Systematic variation in the observed exciton PL from 510 nm to 350 nm as the alloy composition is changed, is attributed to the structural readjustment of crystal packing upon increase of the Br content in the Pb-I inorganic network. The energy separation between exciton absorption and PL is attributed to the modified exciton density of states and diffusion of excitons from relatively higher energy states corresponding to bromine rich sites towards the lower energy iodine sites. Apart from compositional fluctuations, these excitons show remarkable reversible flips at temperature-induced phase transitions. All the results are successfully correlated with thermal and structural studies. Such structural engineering flexibility in these hybrids allows selective tuning of desirable exciton properties within suitable operating temperature ranges. Such wide-range PL tunability and reversible exciton switching in these novel IO hybrids paves the way to potential applications in new generation of optoelectronic devices

  7. Structural tunability and switchable exciton emission in inorganic-organic hybrids with mixed halides

    Science.gov (United States)

    Ahmad, Shahab; Baumberg, Jeremy J.; Vijaya Prakash, G.

    2013-12-01

    Room-temperature tunable excitonic photoluminescence is demonstrated in alloy-tuned layered Inorganic-Organic (IO) hybrids, (C12H25NH3)2PbI4(1-y)Br4y (y = 0 to 1). These perovskite IO hybrids adopt structures with alternating stacks of low-dimensional inorganic and organic layers, considered to be naturally self-assembled multiple quantum wells. These systems resemble stacked monolayer 2D semiconductors since no interlayer coupling exists. Thin films of IO hybrids exhibit sharp and strong photoluminescence (PL) at room-temperature due to stable excitons formed within the low-dimensional inorganic layers. Systematic variation in the observed exciton PL from 510 nm to 350 nm as the alloy composition is changed, is attributed to the structural readjustment of crystal packing upon increase of the Br content in the Pb-I inorganic network. The energy separation between exciton absorption and PL is attributed to the modified exciton density of states and diffusion of excitons from relatively higher energy states corresponding to bromine rich sites towards the lower energy iodine sites. Apart from compositional fluctuations, these excitons show remarkable reversible flips at temperature-induced phase transitions. All the results are successfully correlated with thermal and structural studies. Such structural engineering flexibility in these hybrids allows selective tuning of desirable exciton properties within suitable operating temperature ranges. Such wide-range PL tunability and reversible exciton switching in these novel IO hybrids paves the way to potential applications in new generation of optoelectronic devices.

  8. Core-shell nanophosphor architecture: toward efficient energy transport in inorganic/organic hybrid solar cells.

    Science.gov (United States)

    Li, Qinghua; Yuan, Yongbiao; Chen, Zihan; Jin, Xiao; Wei, Tai-huei; Li, Yue; Qin, Yuancheng; Sun, Weifu

    2014-08-13

    In this work, a core-shell nanostructure of samarium phosphates encapsulated into a Eu(3+)-doped silica shell has been successfully fabricated, which has been confirmed by X-ray diffraction, transmission electron microscopy (TEM), and high-resolution TEM. Moreover, we report the energy transfer process from the Sm(3+) to emitters Eu(3+) that widens the light absorption range of the hybrid solar cells (HSCs) and the strong enhancement of the electron-transport of TiO2/poly(3-hexylthiophene) (P3HT) bulk heterojunction (BHJ) HSCs by introducing the unique core-shell nanoarchitecture. Furthermore, by applying femtosecond transient absorption spectroscopy, we successfully obtain the electron transport lifetimes of BHJ systems with or without incorporating the core-shell nanophosphors (NPs). Concrete evidence has been provided that the doping of core-shell NPs improves the efficiency of electron transfers from donor to acceptor, but the hole transport almost remains unchanged. In particular, the hot electron transfer lifetime was shortened from 30.2 to 16.7 ps, i.e., more than 44% faster than pure TiO2 acceptor. Consequently, a notable power conversion efficiency of 3.30% for SmPO4@Eu(3+):SiO2 blended TiO2/P3HT HSCs is achieved at 5 wt % as compared to 1.98% of pure TiO2/P3HT HSCs. This work indicates that the core-shell NPs can efficiently broaden the absorption region, facilitate electron-transport of BHJ, and enhance photovoltaic performance of inorganic/organic HSCs.

  9. Diffusion of radioactively tagged penetrants through rubbery polymers. II. Dependence on molecular length of penetrant

    International Nuclear Information System (INIS)

    Rhee, C.K.; Ferry, J.D.; Fetters, L.J.

    1977-01-01

    The diffusion of radioactively tagged n-hexadecane, n-dotriacontane, and a polybutadiene oligomer with molecular weight 1600 has been studied in 12 rubbery polymers. Diffusion coefficients were obtained from the theory for the thin smear method: for n-hexadecane and for n-dotriacontane (with one exception), in the form appropriate for a completely miscible polymer-penetrant pair, and for the oligomer in the form appropriate for slow entry of the pentrant across the penetrant-polymer interface. For the four flexible linear penetrants, n-dodecane, n-hexadecane, n-dotriacontane, and oligomer, the ratios of diffusion coefficients (or translational friction coefficients) are nearly the same in every polymer. It is concluded that these penetrants travel with similar segmentwise motions, although that is not the case with bulkier, more rigid penetrants. For the three normal paraffins, the friction coefficient is approximately proportional to molecular weight, but that for the oligomer is smaller than would be predicted on this basis

  10. Plastic scintillation dosimetry: Optimal selection of scintillating fibers and scintillators

    International Nuclear Information System (INIS)

    Archambault, Louis; Arsenault, Jean; Gingras, Luc; Sam Beddar, A.; Roy, Rene; Beaulieu, Luc

    2005-01-01

    Scintillation dosimetry is a promising avenue for evaluating dose patterns delivered by intensity-modulated radiation therapy plans or for the small fields involved in stereotactic radiosurgery. However, the increase in signal has been the goal for many authors. In this paper, a comparison is made between plastic scintillating fibers and plastic scintillator. The collection of scintillation light was measured experimentally for four commercial models of scintillating fibers (BCF-12, BCF-60, SCSF-78, SCSF-3HF) and two models of plastic scintillators (BC-400, BC-408). The emission spectra of all six scintillators were obtained by using an optical spectrum analyzer and they were compared with theoretical behavior. For scintillation in the blue region, the signal intensity of a singly clad scintillating fiber (BCF-12) was 120% of that of the plastic scintillator (BC-400). For the multiclad fiber (SCSF-78), the signal reached 144% of that of the plastic scintillator. The intensity of the green scintillating fibers was lower than that of the plastic scintillator: 47% for the singly clad fiber (BCF-60) and 77% for the multiclad fiber (SCSF-3HF). The collected light was studied as a function of the scintillator length and radius for a cylindrical probe. We found that symmetric detectors with nearly the same spatial resolution in each direction (2 mm in diameter by 3 mm in length) could be made with a signal equivalent to those of the more commonly used asymmetric scintillators. With augmentation of the signal-to-noise ratio in consideration, this paper presents a series of comparisons that should provide insight into selection of a scintillator type and volume for development of a medical dosimeter

  11. Fabrication of InP-pentacene inorganic-organic hybrid heterojunction using MOCVD grown InP for photodetector application

    Science.gov (United States)

    Sarkar, Kalyan Jyoti; Pal, B.; Banerji, P.

    2018-04-01

    We fabricated inorganic-organic hybrid heterojunction between indium phosphide (InP) and pentacene for photodetector application. InP layer was grown on n-Si substrate by atmospheric pressure metal organic chemical vapour deposition (MOCVD) technique. Morphological properties of InP and pentacene thin film were characterized by atomic force microscopy (AFM). Current-voltage characteristics were investigated in dark and under illumination condition at room temperature. During illumination, different wavelengths of visible and infrared light source were employed to perform the electrical measurement. Enhancement of photocurrent was observed with decreasing in wavelength of incident photo radiation. Ideality factor was found to be 1.92. High rectification ratio of 225 was found at ± 3 V in presence of infrared light source. This study provides new insights of inorganic-organic hybrid heterojunction for broadband photoresponse in visible to near infrared (IR) region under low reverse bias condition.

  12. Inorganic/organic hybrid nanocomposite coating applications: Formulation, characterization, and evaluation

    Science.gov (United States)

    Eyassu, Tsehaye

    Nanotechnology applications in coatings have shown significant growth in recent years. Systematic incorporation of nano-sized inorganic materials into polymer coating enhances optical, electrical, thermal and mechanical properties significantly. The present dissertation will focus on formulation, characterization and evaluation of inorganic/organic hybrid nanocomposite coatings for heat dissipation, corrosion inhibition and ultraviolet (UV) and near infrared (NIR) cut applications. In addition, the dissertation will cover synthesis, characterization and dispersion of functional inorganic fillers. In the first project, we investigated factors that can affect the "Molecular Fan" cooling performance and efficiency. The investigated factors and conditions include types of nanomaterials, size, loading amount, coating thickness, heat sink substrate, substrate surface modification, and power input. Using the optimal factors, MF coating was formulated and applied on commercial HDUs, and cooling efficiencies up to 22% and 23% were achieved using multi-walled carbon nanotube and graphene fillers. The result suggests that molecular fan action can reduce the size and mass of heat-sink module and thus offer a low cost of LED light unit. In the second project, we report the use of thin organic/inorganic hybrid coating as a protection for corrosion and as a thermal management to dissipate heat from galvanized steel. Here, we employed the in-situ phosphatization method for corrosion inhibition and "Molecular fan" technique to dissipate heat from galvanized steel panels and sheets. Salt fog tests reveal successful completion of 72 hours corrosion protection time frame for samples coated with as low as ~0.7microm thickness. Heat dissipation measurement shows 9% and 13% temperature cooling for GI and GL panels with the same coating thickness of ~0.7microm respectively. The effect of different factors, in-situ phosphatization reagent (ISPR), cross-linkers and nanomaterial on corrosion

  13. Three inorganic-organic hybrid complexes based on isopolymolybdate and derivatives of 1H-4-nitroimidazole

    Science.gov (United States)

    Zhang, Xiaoyu; Xi, Rui; Yin, Sulu; Cao, Xiaoran; Zhang, Yongliang; Lin, Ling; Chen, Rui; Wu, Hua

    2018-02-01

    Three inorganic-organic diverse CuI motifs of [CuI(bnip)]2(Mo6O19) (1), CuI4(bnib)3(β-Mo8O26)(H2O) (2) and [CuI(bnih)]2(Mo6O19)·H2O (3) [bnip = 1,3-bis(4-nitro-1H-imidazol-1-yl)propane, bnib = 1,4-bis(4-nitro-1H-imidazol-1-yl)butane, and bnih = 1,6-bis(4-nitro-1H-imidazol-1-yl)hexane] based on three diverse flexible ligands and isopolyoxomolybdate clusters have been successfully synthesized under solvothermal conditions at different pH values and ratio of the solvents. Their structures have been characterized by single-crystal X-ray diffraction analyses, infrared spectra (IR) and elemental analyses. For compound 1, the CuI ions are linked by bnip ligands to form a 2D 44 cationic layer, the 2D layers are packed in offset fashions through C-H···O hydrogen bonding interactions to generate a 3D supramolecular network with 1D channels, and the isolated [Mo6O19]2- polyanions are located in the channels. In compound 2, three bnib ligands are brigded by four CuI ions to form a unique unit of Cu4(binb)3(H2O)2, and the units are connected by Mo8O264- anions to generate an infinite 1D branched chain, which are further bridged by hydrogen bonding interactions to form a 2D supramolecular structure. In compound 3, two types of -Cu-bnih-Cu- chains are crossed each other to assemble a 3D supramolecular framework with 1D cationic channel by the hydrogen bonding interactions, and the channels are occupied by Mo6O192- anions. Furthermore, the thermal stabilities, power X-ray diffraction, the photoluminescent properties of compounds 1-3 and the electrochemical properties of compounds 1 and 2 have been also investigated.

  14. Liquid scintillation solution

    International Nuclear Information System (INIS)

    Long, E.C.

    1977-01-01

    A liquid scintillation solution is described which includes (1) a scintillation solvent (toluene and xylene), (2) a primary scintillation solute (PPO and Butyl PBD), (3) a secondary scintillation solute (POPOP and Dimethyl POPOP), (4) a plurality of substantially different surfactants and (5) a filter dissolving and/or transparentizing agent. 8 claims

  15. Scintillator structure

    International Nuclear Information System (INIS)

    Cusano, D.A.; Swank, R.K.; White, P.J.

    1978-01-01

    Scintillator structures are described in which the phosphor is embedded or suspended in an optically transparent matrix which is selected or adjusted to have an index of refraction which is approximately equal to that of the phosphor at the wavelength of the light emitted by the phosphor. The matrix may be glass, copoly 2-vinyl naphthalene/vinyl toluene or a liquid e.g. Br-naphthalene and optionally CH 3 I, the ratio of components being adjusted to give the desired refractive index. The polymer may be made in situ or a mixture of phosphor and polymer formed e.g. by freeze drying a solution and pulverizing, and then heating. Specified dyes may be used for converting the emitted light to other wavelengths. (author)

  16. Sol-gel synthesis and characterization of hybrid inorganic-organic Tb(III)-terephthalate containing layered double hydroxides

    Science.gov (United States)

    Smalenskaite, A.; Salak, A. N.; Ferreira, M. G. S.; Skaudzius, R.; Kareiva, A.

    2018-06-01

    Mg3/Al1 and Mg3Al1-xTbx layered double hydroxides (LDHs) intercalated with terephthalate anion were synthesized using sol-gel method. The obtained materials were characterized by X-ray diffraction (XRD) analysis, infrared (FTIR) spectroscopy, fluorescence spectroscopy (FLS) and scanning electron microscopy (SEM). The Tb3+ substitution effects in the Mg3Al1-xTbx LDHs were investigated by changing the Tb3+ concentration in the cation layers. The study indicates that the organic guest-terephthalate in the interlayer spacing of the LDH host influences the luminescence of the hybrid inorganic-organic materials.

  17. In situ intercalation strategies for device-quality hybrid inorganic-organic self-assembled quantum wells

    Science.gov (United States)

    Pradeesh, K.; Baumberg, J. J.; Prakash, G. Vijaya

    2009-07-01

    Thin films of self-organized quantum wells of inorganic-organic hybrid perovskites of (C6H9C2H4NH3)2PbI4 are formed from a simple intercalation strategy to yield well-ordered uniform films over centimeter-size scales. These films compare favorably with traditional solution-chemistry-synthesized thin films. The hybrid films show strong room-temperature exciton-related absorption and photoluminescence, which shift with fabrication protocol. We demonstrate the potential of this method for electronic and photonic device applications.

  18. Synthesis,crystal structure and properties of inorganic-organic hybrid polymers based on 8-hydroxylquinoline-5-sulfonic acid

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    Two new inorganic-organic hybrid polymers, Mn(QS)(H2O) (1) and Co(QS)(H2O)2 (2) (H2QS=8-hydroxyl-quinoline-5-sulfonic acid), based on 8-hydroxylquinoline-5-sulfonate ligand, have been synthesized under solvothermal conditions and their structures were solved by single-crystal X-ray diffraction analysis. Compound 1 is a three-dimensional open framework with rutile topology structure, and compound 2 is a three-dimensional supramolecular structure. These compounds were characterized by powder XRD, infrared spectroscopy, thermogravimetric analysis, fluorescence properties and magnetism properties.

  19. Inorganic/organic nanocomposites: Reaching a high filler content without increasing viscosity using core-shell structured nanoparticles

    Energy Technology Data Exchange (ETDEWEB)

    Benhadjala, W., E-mail: warda.benhadjala@cea.fr [IMS Laboratory - UMR CNRS 5218, University of Bordeaux, 351 Cours de la Libération, 33405 Talence (France); CEA, LETI, Minatec Campus, 38000 Grenoble (France); Gravoueille, M.; Weiss, M. [EDF, Centre d' Expertise et d' Inspection dans les Domaines de la Réalisation et de l' Exploitation (CEIDRE), Chinon, BP 80, 37420 Avoine (France); Bord-Majek, I.; Béchou, L.; Ousten, Y. [IMS Laboratory - UMR CNRS 5218, University of Bordeaux, 351 Cours de la Libération, 33405 Talence (France); Suhir, E. [Maseeh College of Engineering and Computer Science, Portland State University, Oregon 97201 (United States); Buet, M.; Louarn, M.; Rougé, F.; Gaud, V. [Polyrise SAS, 16 Avenue Pey Berland, 33607 Pessac (France)

    2015-11-23

    Extensive research is being conducted on the development of inorganic/organic nanocomposites for a wide variety of applications in microelectronics, biotechnologies, photonics, adhesives, or optical coatings. High filler contents are usually required to fully optimize the nanocomposites properties. However, numerous studies demonstrated that traditional composite viscosity increases with increasing the filler concentration reducing therefore significantly the material processability. In this work, we synthesized inorganic/organic core-shell nanocomposites with different shell thicknesses. By reducing the shell thickness while maintaining a constant core size, the nanoparticle molecular mass decreases but the nanocomposite filler fraction is correlatively increased. We performed viscosity measurements, which clearly highlighted that intrinsic viscosity of hybrid nanoparticles decreases as the molecular mass decreases, and thus, as the filler fraction increases, as opposed to Einstein predictions about the viscosity of traditional inorganic/polymer two-phase mixtures. This exceptional behavior, modeled by Mark-Houwink-Sakurada equation, proves to be a significant breakthrough for the development of industrializable nanocomposites with high filler contents.

  20. High efficiency scintillation detectors

    International Nuclear Information System (INIS)

    Noakes, J.E.

    1976-01-01

    A scintillation counter consisting of a scintillation detector, usually a crystal scintillator optically coupled to a photomultiplier tube which converts photons to electrical pulses is described. The photomultiplier pulses are measured to provide information on impinging radiation. In inorganic crystal scintillation detectors to achieve maximum density, optical transparency and uniform activation, it has been necessary heretofore to prepare the scintillator as a single crystal. Crystal pieces fail to give a single composite response. Means are provided herein for obtaining such a response with crystal pieces, such means comprising the combination of crystal pieces and liquid or solid organic scintillator matrices having a cyclic molecular structure favorable to fluorescence. 8 claims, 6 drawing figures

  1. Scintillation counting apparatus

    International Nuclear Information System (INIS)

    Noakes, J.E.

    1978-01-01

    Apparatus is described for the accurate measurement of radiation by means of scintillation counters and in particular for the liquid scintillation counting of both soft beta radiation and gamma radiation. Full constructional and operating details are given. (UK)

  2. Liquid scintillation solution

    International Nuclear Information System (INIS)

    Long, E.C.

    1976-01-01

    The invention deals with a liquid scintillation solution which contains 1) a scintillation solvent (toluol), 2) a primary scintillation solute (PPO), 3) a secondary scintillation solute (dimethyl POPOP), 4) several surfactants (iso-octyl-phenol polyethoxy-ethanol and sodium di-hexyl sulfosuccinate) essentially different from one another and 5) a filter resolution and/or transparent-making agent (cyclic ether, especially tetrahydrofuran). (HP) [de

  3. Scintillator manufacture at Fermilab

    Energy Technology Data Exchange (ETDEWEB)

    Mellott, K.; Bross, A.; Pla-Dalmau, A.

    1998-08-01

    A decade of research into plastic scintillation materials at Fermilab is reviewed. Early work with plastic optical fiber fabrication is revisited and recent experiments with large-scale commercial methods for production of bulk scintillator are discussed. Costs for various forms of scintillator are examined and new development goals including cost reduction methods and quality improvement techniques are suggested.

  4. WORKSHOP: Scintillating fibre detectors

    International Nuclear Information System (INIS)

    Anon.

    1989-01-01

    Scintillating fibre detector development and technology for the proposed US Superconducting Supercollider, SSC, was the subject of a recent workshop at Fermilab, with participation from the high energy physics community and from industry. Sessions covered the current status of fibre technology and fibre detectors, new detector applications, fluorescent materials and scintillation compositions, radiation damage effects, amplification and imaging structures, and scintillation fibre fabrication techniques

  5. Liquid scintillation measurement. I

    International Nuclear Information System (INIS)

    Rexa, R.; Tykva, R.

    1983-01-01

    The individual components of scintillation solutions and their tasks are listed. Explained briefly is the scintillation process in a liquid scintillator. Factors are discussed which influence this process as are methods applied to supress their influence. They include: ionization quenching, quenching by dilution and concentration, chemical, colour, phase and photon quenching and single-photon events causing an undesirable backgorund. (M.D.)

  6. Scintillation response of organic and inorganic scintillators

    CERN Document Server

    Papadopoulos, L M

    1999-01-01

    A method to evaluate the scintillation response of organic and inorganic scintillators to different heavy ionizing particles is suggested. A function describing the rate of the energy consumed as fluorescence emission is derived, i.e., the differential response with respect to time. This function is then integrated for each ion and scintillator (anthracene, stilbene and CsI(Tl)) to determine scintillation response. The resulting scintillation responses are compared to the previously reported measured responses. Agreement to within 2.5% is observed when these data are normalized to each other. In addition, conclusions regarding the quenching parameter kB dependence on the type of the particle and the computed values of kB for certain ions are included. (author)

  7. Tunable and white light emitting AlPO4 mesoporous glass by design of inorganic/organic luminescent species

    Directory of Open Access Journals (Sweden)

    Jin He

    2015-04-01

    Full Text Available The realization of tunable and white light emitting sources employed by UV-LED with single-host phosphors has been an exciting development in the search for high luminous efficiency and excellent color rendering index white-light source. A tunable and white light emitting mesoporous glass was prepared by utilizing both inorganic/organic (Europium/coumarin luminescent species in the meso-structure. The tunable and white light emission was deliberately designed by CIE calculation based on the individual emission spectra, which was realized by tailoring the emission of Eu2+/Eu3+ ions and coumarin 535 in sol-gel AlPO4 mesoporous glass. This simple and versatile procedure is not limited in the combination of rare earth and organic dye and is therefore extendable to other luminescent species in meso-structure for color-tunable efficient solid-state lighting sources.

  8. Inorganic-organic hybrid polyoxometalate containing supramolecular helical chains: Preparation, characterization and application in chemically bulk-modified electrode

    International Nuclear Information System (INIS)

    Han Zhangang; Zhao Yulong; Peng Jun; Liu Qun; Wang Enbo

    2005-01-01

    An inorganic-organic hybrid polyoxometalate (POM) (Hbpy) 4 [SiMo 12 O 40 ] (1) (bpy = 2,4-bipyridine), has been prepared and characterized. X-ray diffraction study reveals that compound 1 contains interesting organic double helical chains. The hybrid nanoparticles was used as a solid bulkmodifier to fabricate a three-dimensional chemically modified carbon paste electrode (1-CPE) by direct mixing. The electrochemical behavior and electrocatalysis of 1-CPE has been studied in detail. The results indicate that 1-CPE has a good electrocatalytic activity toward the reduction of nitrite in 1 M H 2 SO 4 aqueous solution. 1-CPE shows remarkable stability that can be ascribed to the interactions existed between POM anions and organic double helical bpy chains, which are very important for practical applications in electrode modification

  9. Larger spontaneous polarization ferroelectric inorganic-organic hybrids: [PbI3](infinity) chains directed organic cations aggregation to Kagomé-shaped tubular architecture.

    Science.gov (United States)

    Zhao, Hai-Rong; Li, Dong-Ping; Ren, Xiao-Ming; Song, You; Jin, Wan-Qin

    2010-01-13

    Four isostructural inorganic-organic hybrid ferroelectric compounds, assembled from achiral 3-R-benzylidene-1-aminopyridiniums (R = NO(2), Br, Cl, or F for 1-4, respectively) and [PbI(3)](-) anions with the chiral Kagomé-shaped tubular aggregating architecture, show larger spontaneous polarizations.

  10. Two inorganic-organic hybrid materials based on polyoxometalate anions and methylene blue: Preparations, crystal structures and properties

    International Nuclear Information System (INIS)

    Nie Shanshan; Zhang Yaobin; Liu Bin; Li Zuoxi; Hu Huaiming; Xue Ganglin; Fu Feng; Wang Jiwu

    2010-01-01

    Two novel inorganic-organic hybrid materials based on an organic dye cation methylene blue (MB) and Lindqvist-type POM polyanions, [C 22 H 18 N 3 S] 2 Mo 6 O 19 2DMF (1) and [C 22 H 18 N 3 S] 2 W 6 O 19 2DMF (2) were synthesized under ambient conditions and characterized by CV, IR spectroscopy, solid diffuse reflectance spectrum, UV-vis spectra in DMF solution, luminescent spectrum and single crystal X-ray diffraction. Crystallographic data reveal that compounds 1 and 2 are isostructural and both crystallize in the triclinic space group P1-bar . Their crystal structures present that the layers of organic molecules and inorganic anions array alternatively, and there exist strong π...π stacking interactions between dimeric MB cations and near distance interactions among organic dye cations, Lindqvist-type POM polyanions and DMF molecules. The solid diffuse reflectance spectra and UV-vis spectra in DMF solution appear new absorption bands ascribed to the charge-transfer transition between the cationic MB donor and the POM acceptors. Studies of the photoluminescent properties show that the formation of 1 and 2 lead to the fluorescence quenching of starting materials. -- Graphical abstract: Their crystal structures present that the layers of organic molecules and inorganic anions array alternatively, and there exist strong π...π stacking interactions between dimeric MB cations. Display Omitted

  11. Sorption and thermodynamic of cation-basic center interactions of inorganic-organic hybrids synthesized from RUB-18

    Energy Technology Data Exchange (ETDEWEB)

    Macedo, T.R. [Institute of Chemistry, University of Campinas, UNICAMP, P.O. Box 6154, 13084-971 Campinas, Sao Paulo (Brazil); Petrucelli, G.C. [Institute of Chemistry, Federal University of Goias, UFG, P.O. Box 03, 75805-190 Jatai, Goias (Brazil); Airoldi, C., E-mail: airoldi@iqm.unicamp.br [Institute of Chemistry, University of Campinas, UNICAMP, P.O. Box 6154, 13084-971 Campinas, Sao Paulo (Brazil)

    2010-04-20

    Synthesized nanostructured hybrids from RUB-18 layered silicate, containing one (N) or three (3N) basic nitrogen atoms attached to pendant chains were applied for copper, nickel and cobalt sorptions. The isotherms obtained from batchwise processes were adjusted to the Freundlich and the Langmuir-Freundlich models for heterogeneous systems. The basic nitrogen centers/acidic cation interactions were followed by calorimetry under batchwise conditions and the results were analyzed by a modified Langmuir equation. The exothermic enthalpic values of -2.50 {+-} 0.30, -1.62 {+-} 0.10 and -1.35 {+-} 0.20 and -15.61 {+-} 0.20, -8.05 {+-} 0.14 and -20.48 {+-} 0.15 kJ mol{sup -1}, obtained for Cu{sup 2+}, Ni{sup 2+} and Co{sup 2+} titrations with C-RUB-xN (x = 1, 3) materials, suggest a favorable process at the solid/liquid interface for inorganic/organic hybrid cation sorptions. These thermodynamic data, expressed also by reaction spontaneity, infer the use of such hybrids for cation removal from aqueous solution.

  12. Soft templating strategies for the synthesis of mesoporous materials: inorganic, organic-inorganic hybrid and purely organic solids.

    Science.gov (United States)

    Pal, Nabanita; Bhaumik, Asim

    2013-03-01

    With the discovery of MCM-41 by Mobil researchers in 1992 the journey of the research on mesoporous materials started and in the 21st century this area of scientific investigation have extended into numerous branches, many of which contribute significantly in emerging areas like catalysis, energy, environment and biomedical research. As a consequence thousands of publications came out in large varieties of national and international journals. In this review, we have tried to summarize the published works on various synthetic pathways and formation mechanisms of different mesoporous materials viz. inorganic, organic-inorganic hybrid and purely organic solids via soft templating pathways. Generation of nanoscale porosity in a solid material usually requires participation of organic template (more specifically surfactants and their supramolecular assemblies) called structure-directing agent (SDA) in the bottom-up chemical reaction process. Different techniques employed for the syntheses of inorganic mesoporous solids, like silicas, metal doped silicas, transition and non-transition metal oxides, mixed oxides, metallophosphates, organic-inorganic hybrids as well as purely organic mesoporous materials like carbons, polymers etc. using surfactants are depicted schematically and elaborately in this paper. Moreover, some of the frontline applications of these mesoporous solids, which are directly related to their functionality, composition and surface properties are discussed at the appropriate places. Copyright © 2012 Elsevier B.V. All rights reserved.

  13. Investigation of the two-photon polymerisation of a Zr-based inorganic-organic hybrid material system

    International Nuclear Information System (INIS)

    Bhuian, B.; Winfield, R.J.; O'Brien, S.; Crean, G.M.

    2006-01-01

    Two-photon polymerisation of photo-sensitive materials allows the fabrication of three dimensional micro- and nano-structures for photonic, electronic and micro-system applications. However the usable process window and the applicability of this fabrication technique is significantly determined by the properties of the photo-sensitive material employed. In this study investigation of a custom inorganic-organic hybrid system, cross-linked by a two-photon induced process, is described. The material was produced by sol-gel synthesis using a silicon alkoxide species that also possessed methacrylate functionality. Stabilized zirconium alkoxide precursors were added to the precursor solution in order to reduce drying times and impart enhanced mechanical stability to deposited films. This enabled dry films to be used in the polymerisation process. A structural, optical and mechanical analysis of the optimised sol-gel material is presented. A Ti:sapphire laser with 80 MHz repetition rate, 100 fs pulse duration and 795 nm is used. The influence of both material system and laser processing parameters including: laser power, photo-initiator concentration and zirconium loading, on achievable micro-structure and size is presented

  14. Scintillator material. Szintillatormaterial

    Energy Technology Data Exchange (ETDEWEB)

    Siegmund, M; Bendig, J; Regenstein, W

    1987-11-25

    A scintillator material for detection and quantitative determination of ionizing radiation is discussed consisting of an acridone dissolved in a fluid or solid medium. Solvent mixtures with at least one protogenic component or polymers and copolymers are used. The scintillator material is distinguished by an excellent stability at high energy doses.

  15. Synthesis, structural, thermal and optical studies of inorganic-organic hybrid semiconductors, R-PbI4

    Science.gov (United States)

    Pradeesh, K.; Nageswara Rao, K.; Vijaya Prakash, G.

    2013-02-01

    Wide varieties of naturally self-assembled two-dimensional inorganic-organic (IO) hybrid semiconductors, (4-ClC6H4NH3)2PbI4, (C6H9C2H4NH3)2PbI4, (CnH2n+1NH3)2PbI4 (where n = 12, 16, 18), (CnH2n-1NH3)2PbI4 (where n = 3, 4, 5), (C6H5C2H4NH3)2PbI4, NH3(CH2)12NH3PbI4, and (C4H3SC2H4NH3)2PbI4, were fabricated by intercalating structurally diverse organic guest moieties into lead iodide perovskite structure. The crystal packing of all these fabricated IO-hybrids comprises of well-ordered organic and inorganic layers, stacked-up alternately along c-axis. Almost all these hybrids are thermally stable upto 200 °C and show strong room-temperature exciton absorption and photoluminescence features. These strongly confined optical excitons are highly influenced by structural deformation of PbI matrix due to the conformation of organic moiety. A systematic correlation of optical exciton behavior of IO-hybrids with the organic/inorganic layer thicknesses, intercalating organic moieties, and various structural disorders were discussed. This systematic study clearly suggests that the PbI layer crumpling is directly responsible for the tunability of optical exciton energy.

  16. Synthesis of novel inorganic-organic hybrid materials for simultaneous adsorption of metal ions and organic molecules in aqueous solution

    Energy Technology Data Exchange (ETDEWEB)

    Jin, Xinliang [State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Institute of Biochemical Engineering and Environmental Technology, Lanzhou University, Lanzhou 730000 (China); Li, Yanfeng, E-mail: liyf@lzu.edu.cn [State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Institute of Biochemical Engineering and Environmental Technology, Lanzhou University, Lanzhou 730000 (China); Yu, Cui; Ma, Yingxia; Yang, Liuqing; Hu, Huaiyuan [State Key Laboratory of Applied Organic Chemistry, College of Chemistry and Chemical Engineering, Institute of Biochemical Engineering and Environmental Technology, Lanzhou University, Lanzhou 730000 (China)

    2011-12-30

    Highlights: Black-Right-Pointing-Pointer Novel hybrid materials were synthesized and employed in the absorption of heavy metal and organic pollutants. Black-Right-Pointing-Pointer A novel method for amphiphilic adsorbent material synthesis was first reported in this paper. Black-Right-Pointing-Pointer The adsorbent material showed excellent adsorption capacity to Pb(II) and phenol. - Abstract: In this paper, atom transfer radical polymerization (ATRP) and radical grafting polymerization were combined to synthesize a novel amphiphilic hybrid material, meanwhile, the amphiphilic hybrid material was employed in the absorption of heavy metal and organic pollutants. After the formation of attapulgite (ATP) ATRP initiator, ATRP block copolymers of styrene (St) and divinylbenzene (DVB) were grafted from it as ATP-P(S-b-DVB). Then radical polymerization of acrylonitrile (AN) was carried out with pendent double bonds in the DVD units successfully, finally we got the inorganic-organic hybrid materials ATP-P(S-b-DVB-g-AN). A novel amphiphilic hybrid material ATP-P(S-b-DVB-g-AO) (ASDO) was obtained after transforming acrylonitrile (AN) units into acrylamide oxime (AO) as hydrophilic segment. The adsorption capacity of ASDO for Pb(II) could achieve 131.6 mg/g, and the maximum removal capacity of ASDO towards phenol was found to be 18.18 mg/g in the case of monolayer adsorption at 30 Degree-Sign C. The optimum pH was 5 for both lead and phenol adsorption. The adsorption kinetic suited pseudo-second-order equation and the equilibrium fitted the Freundlich model very well under optimal conditions. At the same time FT-IR, TEM and TGA were also used to study its structure and property.

  17. Magnetic phase transition in layered inorganic-organic hybrid (C12H25NH3)2CuCl4

    Science.gov (United States)

    Bochalya, Madhu; Kumar, Sunil; Kanaujia, Pawan K.; Prakash, G. Vijaya

    2018-05-01

    Inorganic-organic (IO) hybrids are material systems which have become an interesting theme of research for physicist and chemists recently due to the possibility of engineering specific magnetic, thermal or optoelectronic properties by playing around with the transition metal, halides and the organic components. Our experiments on (C12H25NH3)2CuCl4 show that the system exhibits a long range ferromagnetic order below ˜11 K. In such an inorganic-organic hybrid system, Jahn-Teller distortion of the copper ions results into a weak ferromagnetic order as compared to the antiferromagnetic spin-spin exchange in the pure inorganic CuCl2 compound. Moreover, this particular hybrid system also exhibits photoluminescence when excited below absorption maximum related to charge transfer peak though the effect is much weaker as compared to that in extensively studied other MX4-based (M = Sn, Pb; X = Cl, Br, I) counterparts.

  18. Phosphor scintillator structure

    International Nuclear Information System (INIS)

    Cusano, D.A.; Prener, J.S.

    1980-01-01

    A method of fabricating scintillators is described in which the phosphor is distributed within the structure in such a way as to enhance the escape of the visible wavelength radiation that would otherwise be dissipated within the scintillator body. Two embodiments of the present invention are disclosed: one in which the phosphor is distributed in a layered structure and another in which the phosphor is dispersed throughout a transparent matrix. (U.K.)

  19. Relating mechanical properties and chemical bonding in an inorganic-organic framework material: a single-crystal nanoindentation study.

    Science.gov (United States)

    Tan, Jin Chong; Furman, Joshua D; Cheetham, Anthony K

    2009-10-14

    We report the application of nanoindentation and atomic force microscopy to establish the fundamental relationships between mechanical properties and chemical bonding in a dense inorganic-organic framework material: Ce(C(2)O(4))(HCO(2)), 1. Compound 1 is a mixed-ligand 3-D hybrid which crystallizes in an orthorhombic space group, in which its three basic building blocks, i.e. the inorganic metal-oxygen-metal (M-O-M) chains and the two organic bridging ligands, (oxalate and formate) are all oriented perpendicular to one another. This unique architecture enabled us to decouple the elastic and plastic mechanical responses along the three primary axes of a single crystal to understand the contribution associated with stiff vs compliant basic building blocks. The (001)-oriented facet that features rigid oxalate ligands down the c-axis exhibits the highest stiffness and hardness (E approximately 78 GPa and H approximately 4.6 GPa). In contrast, the (010)-oriented facet was found to be the most compliant and soft (E approximately 43 GPa and H approximately 3.9 GPa), since the formate ligand, which is the more compliant building block within this framework, constitutes the primary linkages down the b-axis. Notably, intermediate stiffness and hardness (E approximately 52 GPa and H approximately 4.1 GPa) were measured on the (100)-oriented planes. This can be attributed to the Ce-O-Ce chains that zigzag down the a-axis (Ce...Ce metal centers form an angle of approximately 132 degrees) and also the fact that the 9-coordinated CeO(9) polyhedra are expected to be geometrically more compliant. Our results present the first conclusive evidence that the crystal orientation dominated by inorganic chains is not necessarily more robust from the mechanical properties standpoint. Rigid organic bridging ligands (such as oxalate), on the other hand, can be used to produce greater stiffness and hardness properties in a chosen crystallographic orientation. This study demonstrates that

  20. Hybrid inorganic-organic adsorbents Part 1: Synthesis and characterization of mesoporous zirconium titanate frameworks containing coordinating organic functionalities.

    Science.gov (United States)

    Griffith, Christopher S; De Los Reyes, Massey; Scales, Nicholas; Hanna, John V; Luca, Vittorio

    2010-12-01

    A series of functional hybrid inorganic-organic adsorbent materials have been prepared through postsynthetic grafting of mesoporous zirconium titanate xerogel powders using a range of synthesized and commercial mono-, bis-, and tris-phosphonic acids, many of which have never before been investigated for the preparation of hybrid phases. The hybrid materials have been characterized using thermogravimetric analysis, diffuse reflectance infrared (DRIFT) and 31P MAS NMR spectroscopic techniques and their adsorption properties studied using a 153Gd radiotracer. The highest level of surface functionalization (molecules/nm2) was observed for methylphosphonic acid (∼3 molecules/nm2). The level of functionalization decreased with an increase in the number of potential surface coordinating groups of the phosphonic acids. Spectral decomposition of the DRIFT and 31P MAS NMR spectra showed that each of the phosphonic acid molecules coordinated strongly to the metal oxide surface but that for the 1,1-bis-phosphonic acids and tris-phosphonic acids the coordination was highly variable resulting in a proportion of free or loosely coordinated phosphonic acid groups. Functionalization of a porous mixed metal oxide framework with the tris-methylenephosphonic acid (ATMP-ZrTi-0.33) resulted in a hybrid with the highest affinity for 153Gd3+ in nitric acid solutions across a wide range of acid concentrations. The ATMP-ZrTi-0.33 hybrid material extracted 153Gd3+ with a Kd value of 1×10(4) in 0.01 M HNO3 far exceeding that of the other hybrid phases. The unfunctionalized mesoporous mixed metal oxide had negligible affinity for Gd3+ (KdATMP-ZrTi-0.33 hybrid phase for Gd3+ has been determined to be about 0.005 mmol/g in 0.01 M HNO3. This behavior and that of the other hybrid phases suggests that the surface-bound ATMP ligand functions as a chelating ligand toward 153Gd3+ under these acidic conditions.

  1. Scintillating properties of frozen new liquid scintillators

    CERN Document Server

    Britvich, G I; Golovkin, S V; Martellotti, G; Medvedkov, A M; Penso, G; Soloviev, A S; Vasilchenko, V G

    1999-01-01

    The light emission from scintillators which are liquid at room temperature was studied in the interval between $+20$~$^{\\circ}$C and $-120$~$^{\\circ}$C, where the phase transition from liquid to solid takes place. The light yield measured at $-120$~$^{\\circ}$C is about twice as much as that observed at $+20$~$^{\\circ}$C. By cooling the scintillator from $+20$~$^{\\circ}$C to $-120$~$^{\\circ}$C and then heating it from $-120$~$^{\\circ}$C to $+20$~$^{\\circ}$C, the light yield varies in steps at well defined temperatures, which are different for the cooling and heating processes. These hysteresis phenomena appear to be related to the solvent rather than to the dopant. The decay time of scintillation light was measured at $+20$~$^{\\circ}$C and $-120$~$^{\\circ}$C. Whilst at room temperature most of the light is emitted with a decay time of 6--8 ns, at $-120$~$^{\\circ}$C a slower component, with a decay time of 25--35 ns, becomes important.

  2. Inorganic liquid scintillator

    International Nuclear Information System (INIS)

    Pavlicek, Z.; Barta, C.; Jursova, L.

    1986-01-01

    An inorganic liquid scintillator is designed which contains 1 to 30 wt.% of an inorganic molecular compound as the basic active component; the compound contains a cation with an atomic number higher than 47 and a halogen anion. The basic inorganic component is dissolved in water or in an organic solvent in form of non-dissociated molecules or self-complexes in which the bond is preserved between the cation and anion components. The light yield from these scintillators ranges between 70 and 150% of the light yield of a standard organic scintillator based on toluene. They are advantageous in that that they allow to increase the water content in the sample to up to 100%. (M.D.)

  3. Physics of scintillation detectors

    International Nuclear Information System (INIS)

    Novotny, R.

    1991-01-01

    The general concept of a radiation detector is based on three fundamental principles: sensitivity of the device to the radiation of interest which requires a large cross-section in the detector material, detector response function to the physical properties of the radiation. As an example, a scintillation detector for charged particles should allow to identify the charge of the particle, its kinetic energy and the time of impact combined with optimum resolutions. Optimum conversion of the detector response (like luminescence of a scintillator) into electronical signals for further processing. The following article will concentrate on the various aspects of the first two listed principles as far as they appear to be relevant for photon and charged particle detection using organic and inorganic scintillation detectors. (orig.)

  4. Scintillator plate calorimetry

    International Nuclear Information System (INIS)

    Price, L.E.

    1990-01-01

    Calorimetry using scintillator plates or tiles alternated with sheets of (usually heavy) passive absorber has been proven over multiple generations of collider detectors. Recent detectors including UA1, CDF, and ZEUS have shown good results from such calorimeters. The advantages offered by scintillator calorimetry for the SSC environment, in particular, are speed (<10 nsec), excellent energy resolution, low noise, and ease of achieving compensation and hence linearity. On the negative side of the ledger can be placed the historical sensitivity of plastic scintillators to radiation damage, the possibility of nonuniform response because of light attenuation, and the presence of cracks for light collection via wavelength shifting plastic (traditionally in sheet form). This approach to calorimetry is being investigated for SSC use by a collaboration of Ames Laboratory/Iowa State University, Argonne National Laboratory, Bicron Corporation, Florida State University, Louisiana State University, University of Mississippi, Oak Ridge National Laboratory, Virginia Polytechnic Institute and State University, Westinghouse Electric Corporation, and University of Wisconsin

  5. Scintillation proximity assay

    International Nuclear Information System (INIS)

    Hart, H.

    1980-01-01

    In a method of immunological assay two different classes of particles which interact at short distances to produce characteristic detectable signals are employed in a modification of the usual latex fixation test. In one embodiment an aqueous suspension of antigen coated tritiated latex particles (LH) and antigen coated polystyrene scintillant particles (L*) is employed to assay antibody in the aqueous medium. The amount of (LH) (L*) dimer formation and higher order aggregation induced and therefore the concentration of antibody (or antigen) present which caused the aggregation can be determined by using standard liquid scintillation counting equipment. (author)

  6. Microfluidic Scintillation Detectors

    CERN Multimedia

    Microfluidic scintillation detectors are devices of recent introduction for the detection of high energy particles, developed within the EP-DT group at CERN. Most of the interest for such technology comes from the use of liquid scintillators, which entails the possibility of changing the active material in the detector, leading to an increased radiation resistance. This feature, together with the high spatial resolution and low thickness deriving from the microfabrication techniques used to manufacture such devices, is desirable not only in instrumentation for high energy physics experiments but also in medical detectors such as beam monitors for hadron therapy.

  7. Liquid scintillation, counting, and compositions

    International Nuclear Information System (INIS)

    Sena, E.A.; Tolbert, B.M.; Sutula, C.L.

    1975-01-01

    The emissions of radioactive isotopes in both aqueous and organic samples can be measured by liquid scintillation counting in micellar systems. The micellar systems are made up of scintillation solvent, scintillation solute and a mixture of surfactants, preferably at least one of which is relatively oil-soluble water-insoluble and another which is relatively water-soluble oil-insoluble

  8. Scintillation properties of acrylate based plastic scintillator by photoploymerization method

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sung Hwan [Dept. of Radiological Science, Cheongju University, Cheongju (Korea, Republic of); Lee, Joo Il [Dept. of of Radiology, Daegu Health College, Daegu (Korea, Republic of)

    2016-12-15

    In this study, we prepared and characterized a acrylate based UV-curable plastic scintillator. It was used co-polymers TMPTA, DHPA and Ultima GoldTM LLT organic scintillator. The emission spectrum of the plastic scintillator was located in the range of 380⁓520 nm, peaking at 423 nm. And the scintillator is more than 50% transparent in the range of 400⁓ 800 nm. The emission spectrum is well match to the quantum efficiency of photo-multiplier tube and the fast decay time of the scintillation is 12 ns, approximately. This scintillation material provides the possibility of combining 3D printing technology, and then the applications of the plastic scintillator may be expected in human dosimetry etc.

  9. Antibacterial inorganic-organic hybrid coatings on stainless steel via consecutive surface-initiated atom transfer radical polymerization for biocorrosion prevention.

    Science.gov (United States)

    Yuan, S J; Pehkonen, S O; Ting, Y P; Neoh, K G; Kang, E T

    2010-05-04

    To enhance the corrosion resistance of stainless steel (SS) and to impart its surface with antibacterial functionality for inhibiting biofilm formation and biocorrosion, well-defined inorganic-organic hybrid coatings, consisting of a polysilsesquioxane inner layer and quaternized poly(2-(dimethyamino)ethyl methacrylate) (P(DMAEMA)) outer blocks, were prepared via successive surface-initiated atom transfer radical polymerization (ATRP) of 3-(trimethoxysilyl)propyl methacrylate (TMSPMA) and 2-(dimethylamino)ethyl methacrylate (DMAEMA). The cross-linked P(TMASPMA), or polysilsesquioxane, inner layer provided a durable and resistant coating to electrolytes. The pendant tertiary amino groups of the P(DMAEMA) outer block were quaternized with alkyl halide to produce a high concentration of quaternary ammonium groups with biocidal functionality. The so-synthesized inorganic-organic hybrid coatings on the SS substrates exhibited good anticorrosion and antibacterial effects and inhibited biocorrosion induced by sulfate-reducing bacteria (SRB) in seawater media, as revealed by antibacterial assay and electrochemical analyses, and they are potentially useful to steel-based equipment under harsh industrial and marine environments.

  10. Polysiloxane scintillator composition

    Science.gov (United States)

    Walker, J.K.

    1992-05-05

    A plastic scintillator useful for detecting ionizing radiation comprising a matrix which comprises an optically transparent polysiloxane having incorporated therein at least one ionizing radiation-hard fluor capable of converting electromagnetic energy produced in the polysiloxane upon absorption of ionizing radiation to detectable light.

  11. WORKSHOP: Scintillating crystals

    Energy Technology Data Exchange (ETDEWEB)

    Anon.

    1992-12-15

    Scintillating crystals are one of the big spinoff success stories of particle physics, and from 22-26 September an international workshop in Chamonix in the French Alps looked at the increasing role of these materials in pure and applied science and in industry.

  12. Radiopharmaceuticals for bone scintillators

    International Nuclear Information System (INIS)

    Rey, A.M.

    1994-01-01

    One of the diagnostic techniques used in nuclear medicine is the bone scintiscanning with labelled compounds for obtain skeletal images. The main sections in this work are: (1) bone composition and anatomy;(2)skeletal radiopharmaceutical development;(3)physical properties of radionuclides;(4)biological behaviour and chemical structures;(5)radiopharmaceuticals production for skeletal scintillation;(6)kits;(7)dosimetry and toxicity.tabs

  13. WORKSHOP: Scintillating crystals

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    Scintillating crystals are one of the big spinoff success stories of particle physics, and from 22-26 September an international workshop in Chamonix in the French Alps looked at the increasing role of these materials in pure and applied science and in industry

  14. Economical stabilized scintillation detector

    International Nuclear Information System (INIS)

    Anshakov, O.M.; Chudakov, V.A.; Gurinovich, V.I.

    1983-01-01

    An economical scintillation detector with the stabilization system of an integral type is described. Power consumed by the photomultiplier high-voltage power source is 40 mW, energy resolution is not worse than 9%. The given detector is used in a reference detector of a digital radioisotope densimeter for light media which is successfully operating for several years

  15. Uranium-scintillator device

    International Nuclear Information System (INIS)

    Smith, S.D.

    1979-01-01

    The calorimeter subgroup of the 1977 ISABELLE Summer Workshop strongly recommended investigation of the uranium-scintillator device because of its several attractive features: (1) increased resolution for hadronic energy, (2) fast time response, (3) high density (i.e., 16 cm of calorimeter per interaction length), and, in comparison with uranium--liquid argon detectors, (4) ease of construction, (5) simple electronics, and (6) lower cost. The AFM group at the CERN ISR became interested in such a calorimeter for substantially the same reasons, and in the fall of 1977 carried out tests on a uranium-scintillator (U-Sc) calorimeter with the same uranium plates used in their 1974 studies of the uranium--liquid argon (U-LA) calorimeter. The chief disadvantage of the scintillator test was that the uranium plates were too small to fully contain the hadronic showers. However, since the scintillator and liquid argon tests were made with the plates, direct comparison of the two types of devices could be made

  16. Performance of molded plastic scintillators

    International Nuclear Information System (INIS)

    Gen, N.S.; Leman, V.E.; Solomonov, V.M.

    1989-01-01

    The performance of molded plastic scintillators is studied. The plastic scintillators studied were formed by transfer molding and intrusion from a scintillation composition consisting of polystyrene and a standard system of luminescent additives: 2 mass % of paraterphenyl + 0.06 mass % 1,4-di-/2-[5-phenyloxazoyly]/benzene and a plasticizer. The combined effect of mechanical load and temperature was studied. The effect of radiation on molded plastic scintillators was studied using gamma radiation from a 60 Co source. The studies show that the main operating characteristics of molded plastic scintillators are on a par with those of polymerized plastic scintillators. At the same time, molded plastic scintillators are superior in thermal stability at temperatures below the glass transition temperature and with respect to their working temperature range

  17. Determining the critical relative humidity at which the glassy to rubbery transition occurs in polydextrose using an automatic water vapor sorption instrument.

    Science.gov (United States)

    Yuan, Xiaoda; Carter, Brady P; Schmidt, Shelly J

    2011-01-01

    Similar to an increase in temperature at constant moisture content, water vapor sorption by an amorphous glassy material at constant temperature causes the material to transition into the rubbery state. However, comparatively little research has investigated the measurement of the critical relative humidity (RHc) at which the glass transition occurs at constant temperature. Thus, the central objective of this study was to investigate the relationship between the glass transition temperature (Tg), determined using thermal methods, and the RHc obtained using an automatic water vapor sorption instrument. Dynamic dewpoint isotherms were obtained for amorphous polydextrose from 15 to 40 °C. RHc was determined using an optimized 2nd-derivative method; however, 2 simpler RHc determination methods were also tested as a secondary objective. No statistical difference was found between the 3 RHc methods. Differential scanning calorimetry (DSC) Tg values were determined using polydextrose equilibrated from 11.3% to 57.6% RH. Both standard DSC and modulated DSC (MDSC) methods were employed, since some of the polydextrose thermograms exhibited a physical aging peak. Thus, a tertiary objective was to compare Tg values obtained using 3 different methods (DSC first scan, DSC rescan, and MDSC), to determine which method(s) yielded the most accurate Tg values. In general, onset and midpoint DSC first scan and MDSC Tg values were similar, whereas onset and midpoint DSC rescan values were different. State diagrams of RHc and experimental temperature and Tg and %RH were compared. These state diagrams, though obtained via very different methods, showed relatively good agreement, confirming our hypothesis that water vapor sorption isotherms can be used to directly detect the glassy to rubbery transition. Practical Application: The food polymer science (FPS) approach, pioneered by Slade and Levine, is being successfully applied in the food industry for understanding, improving, and

  18. Alpha scintillation radon counting

    International Nuclear Information System (INIS)

    Lucas, H.F. Jr.

    1977-01-01

    Radon counting chambers which utilize the alpha-scintillation properties of silver activated zinc sulfide are simple to construct, have a high efficiency, and, with proper design, may be relatively insensitive to variations in the pressure or purity of the counter filling. Chambers which were constructed from glass, metal, or plastic in a wide variety of shapes and sizes were evaluated for the accuracy and the precision of the radon counting. The principles affecting the alpha-scintillation radon counting chamber design and an analytic system suitable for a large scale study of the 222 Rn and 226 Ra content of either air or other environmental samples are described. Particular note is taken of those factors which affect the accuracy and the precision of the method for monitoring radioactivity around uranium mines

  19. Scintillator detector array

    International Nuclear Information System (INIS)

    Cusano, D.A.; Dibianca, F.A.

    1981-01-01

    This patent application relates to a scintillator detector array for use in computerized tomography and comprises a housing including a plurality of chambers, the said housing having a front wall transmissive to x-rays and side walls opaque to x-rays, such as of tungsten and tantalum, a liquid scintillation medium including a soluble fluor, the solvent for the fluor being disposed in the chambers. The solvent comprises either an intrinsically high Z solvent or a solvent which has dissolved therein a high Z compound e.g. iodo or bromonaphthalene; or toluene, xylene or trimethylbenzene with a lead or tin alkyl dissolved therein. Also disposed about the chambers are a plurality of photoelectric devices. (author)

  20. DETECTORS: scintillating fibres

    International Nuclear Information System (INIS)

    Anon.

    1994-01-01

    In the continual search for improved detection techniques, new materials are continually proving profitable. A good example is scintillating plastic fibres - tiny transparent threads sometimes finer than a human hair which transmit light. The narrowness and flexibility of these fibres was a major breakthrough for endoscopy - non-invasive techniques for viewing the otherwise inaccessible in surgery or machine inspection. In a more sophisticated form, these fibres find ready application in communications technology, where the goal is to transmit information rather than electrical power, replacing conventional and unwieldy current-carrying wire conductors. In particle physics, fibres have long been used to take the tiny scintillations produced when high energy particles hit fluorescent materials and 'conduct' them to photosensitive detectors some distance away

  1. A gamma scintillation spectrometer

    Energy Technology Data Exchange (ETDEWEB)

    Symbalisty, S

    1952-07-01

    A scintillation type gamma ray spectrometer employing coincidence counting, designed and built at the Physics Department of the University of Western Ontario is described. The spectrometer is composed of two anthracene and photomultiplier radiation detectors, two pulse analyzing channels, a coincidence stage, three scalers and a high voltage stabilized supply. A preliminary experiment to test the operation of the spectrometer was performed and the results of this test are presented. (author)

  2. Modular scintillation camera

    International Nuclear Information System (INIS)

    Barrett, H. H.

    1985-01-01

    Improved optical coupling modules to be used in coded-aperture-type radiographic imaging systems. In a first system, a rotating slit coded-aperture is employed between the radioactive object and the module. The module consists of one pair of side-by-side photomultipliers receiving light rays from a scintillation crystal exposed to the object via the coded-aperture. The light rays are guided to the photomultipliers by a mask having a central transverse transparent window, or by a cylindrical lens, the mask or lens being mounted in a light-conveying quartz block assembly providing internal reflections at opposite faces of the assembly. This generates output signals from the photomultipliers which can be utilized to compute one-dimensional coordinate values for restoring the image of the radioactive object on a display screen. In another form of optical coupling module, usable with other types of coded-apertures, four square photomultipliers form a substantially square block and receive light rays from scintillations from a scintillation crystal exposed to the radioactive object via the coded-aperture. The light rays are guided to the photomultipliers by a square mask or a centrally transparent square lens configuration mounted in a light-conveying assembly formed by internally reflecting quartz blocks, the optical rays being directed to the respective photomultipliers so as to generate resultant output signals which can be utilized to compute image coordinate values for two-dimensional representation of the radioactive object being examined

  3. Three inorganic-organic hybrids of bismuth(III) iodide complexes containing substituted 1,2,4-triazole organic components with charaterizations of diffuse reflectance spectra

    International Nuclear Information System (INIS)

    Liu Bing; Xu Ling; Guo Guocong; Huang Jinshun

    2006-01-01

    The reactions of two kinds of substituted 1,2,4-triazoles with BiI 3 yielded three inorganic-organic hybrids: [HL1] 4 [Bi 6 I 22 ].[L1] 4 .4H 2 O (1) (L1=3-(1,2,4-triazole-4-yl)-1H-1,2,4-triazole); [HL2] 4 [Bi 6 I 22 ].6H 2 O (2); [HL2] 2 [Bi 2 I 8 ].[L2] 2 (3) (L2=(m-phenol)-1,2,4-triazole). Both 1 and 2 have polynuclear anions of [Bi 6 I 22 ] 4- to build up the inorganic layers and substituted 1,2,4-triazoles as the organic layers. Hybrid 3 consists of two BiI 5 square pyramids as inorganic layers. There exist hydrogen bondings and I...;I interactions in the structures of 1, 2 and 3. Optical absorption spectra of 1, 2 and 3 reveal the presence of sharp optical gaps of 1.77, 1.77 and 2.07 eV, respectively, suggesting that these materials behave as semiconductors. - Graphical abstract: The reactions of two kinds of the substituted 1,2,4-triazoles with BiI 3 yielded three layered inorganic-organic hybrids [HL1] 4 [Bi 6 I 22 ].[L1] 4 .4H 2 O (1), [HL2] 4 [Bi 6 I 22 ].6H 2 O (2), [HL2] 2 [Bi 2 I 8 ].[L2] 2 (3) with optical gaps of 1.77, 1.77 and 2.07 eV, respectively. The structures of 1-3 are constructed from inorganic layers of polynuclear anions of bismuth iodine and organic layers of the substituted 1,2,4-triazoles

  4. Liquid scintillation counting of chlorophyll

    International Nuclear Information System (INIS)

    Fric, F.; Horickova, B.; Haspel-Horvatovic, E.

    1975-01-01

    A precise and reproducible method of liquid scintillation counting was worked out for measuring the radioactivity of 14 C-labelled chlorophyll a and chlorophyll b solutions without previous bleaching. The spurious count rate caused by luminescence of the scintillant-chlorophyll system is eliminated by using a suitable scintillant and by measuring the radioactivity at 4 to 8 0 C after an appropriate time of dark adaptation. Bleaching of the chlorophyll solutions is necessary only for measuring of very low radioactivity. (author)

  5. 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.

  6. 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

  7. Scintillating-fibre calorimetry

    International Nuclear Information System (INIS)

    Livan, M.; Vercesi, V.; Wigmans, R.

    1995-01-01

    In the past decade, calorimetry based on scintillating plastic fibres as active elements was developed from a conceptual idea to a mature detector technology, which is nowadays widely applied in particle physics experiments. This development and the performance characteristics of representative calorimeters, both for the detection of electromagnetic and hadronic showers, are reviewed. We also discuss new information on shower development processes in dense matter and its application to calorimetric principles that has emerged from some very thorough studies that were performed in the framework of this development. (orig.)

  8. Hybrid scintillators for neutron discrimination

    Science.gov (United States)

    Feng, Patrick L; Cordaro, Joseph G; Anstey, Mitchell R; Morales, Alfredo M

    2015-05-12

    A composition capable of producing a unique scintillation response to neutrons and gamma rays, comprising (i) at least one surfactant; (ii) a polar hydrogen-bonding solvent; and (iii) at least one luminophore. A method including combining at least one surfactant, a polar hydrogen-bonding solvent and at least one luminophore in a scintillation cell under vacuum or an inert atmosphere.

  9. Liquid scintillation in medical diagnosis

    International Nuclear Information System (INIS)

    Painter, K.

    1976-01-01

    With the tremendous increase in the application of radioassay, particularly radioimmunoassay, in the clinical laboratory liquid scintillation counting became an indispensable tool in diagnostic medicine. Few publications, however, have concerned themselves with problem areas which occur with the method in the clinical laboratory. The purpose of this presentation is to summarize our experiences with the liquid scintillation technique in the clinical situation

  10. A user's guide to scintillation

    International Nuclear Information System (INIS)

    Hewish, A.

    1989-01-01

    During the past four decades scintillation methods have been used for remote-sensing distant plasmas and for providing high angular resolution in radioastronomy. This brief review illustrates some of the techniques employed and explains the underlying theory in simple physical terms; it is not intended to be a complete survey of all applications of scintillation. (author)

  11. Laser Beam Scintillation with Applications

    CERN Document Server

    Andrews, Larry C; Young, Cynthia

    2001-01-01

    Renewed interest in laser communication systems has sparked development of useful new analytic models. This book discusses optical scintillation and its impact on system performance in free-space optical communication and laser radar applications, with a detailed look at propagation phenomena and the role of scintillation on system behavior. Intended for practicing engineers, scientists, and students.

  12. Scintillation light transport and detection

    International Nuclear Information System (INIS)

    Gabriel, T.A.; Lillie, R.A.

    1986-08-01

    The MORSE neutron gamma-ray transport code has been modified to allow for the transport of scintillation light. This modified code is used to analyze the light collection characteristics of a large liquid scintillator module (18 x 18 x 350 cm 3 )

  13. Extruding plastic scintillator at Fermilab

    International Nuclear Information System (INIS)

    Pla-Dalmau, Anna; Bross, Alain D.; Rykalin, Viktor V.

    2003-01-01

    An understanding of the costs involved in the production of plastic scintillators and the development of a less expensive material have become necessary with the prospects of building very large plastic scintillation detectors. Several factors contribute to the high cost of plastic scintillating sheets, but the principal reason is the labor-intensive nature of the manufacturing process. In order to significantly lower the costs, the current casting procedures had to be abandoned. Since polystyrene is widely used in the consumer industry, the logical path was to investigate the extrusion of commercial-grade polystyrene pellets with dopants to yield high quality plastic scintillator. This concept was tested and high quality extruded plastic scintillator was produced. The D0 and MINOS experiments are already using extruded scintillator strips in their detectors. An extrusion line has recently been installed at Fermilab in collaboration with NICADD (Northern Illinois Center for Accelerator and Detector Development). This new facility will serve to further develop and improve extruded plastic scintillator. This paper will discuss the characteristics of extruded plastic scintillator and its raw materials, the different manufacturing techniques and the current R andD program at Fermilab

  14. Scintillation properties of GSO

    International Nuclear Information System (INIS)

    Melcher, C.L.; Schweitzer, J.S.; Utsu, T.; Akiyama, S.

    1990-01-01

    The timing properties of Gd 2 SiO 5 :Ce (GSO) single crystal scintillators have previously been evaluated for positron emission tomography applications. The measured time resolution, however, was worse than expected from calculations based on photoelectron yield and a 60 nanosecond exponential decay constant, leading us to further investigate GSO's basic properties. With a time-correlated-single-photon technique, the authors have found two decay components, one of 56 ns and one of 600 ns, the latter containing 10--15% of the total scintillation output. This may explain the difference between the experimental and theoretical time resolutions and confirms a previous hypothesis of a long decay component. In addition, the authors have found that each component's decay constant strongly depends on the cerium concentration. The primary component varies from ∼ 20 ns to ∼ 190 ns and the secondary component varies from ∼ 70 ns to ∼ 1200 ns as the cerium concentration is varied from 5.0 mol% to 0.1 mol%

  15. Surface tensions of multi-component mixed inorganic/organic aqueous systems of atmospheric significance: measurements, model predictions and importance for cloud activation predictions

    Directory of Open Access Journals (Sweden)

    D. O. Topping

    2007-01-01

    Full Text Available In order to predict the physical properties of aerosol particles, it is necessary to adequately capture the behaviour of the ubiquitous complex organic components. One of the key properties which may affect this behaviour is the contribution of the organic components to the surface tension of aqueous particles in the moist atmosphere. Whilst the qualitative effect of organic compounds on solution surface tensions has been widely reported, our quantitative understanding on mixed organic and mixed inorganic/organic systems is limited. Furthermore, it is unclear whether models that exist in the literature can reproduce the surface tension variability for binary and higher order multi-component organic and mixed inorganic/organic systems of atmospheric significance. The current study aims to resolve both issues to some extent. Surface tensions of single and multiple solute aqueous solutions were measured and compared with predictions from a number of model treatments. On comparison with binary organic systems, two predictive models found in the literature provided a range of values resulting from sensitivity to calculations of pure component surface tensions. Results indicate that a fitted model can capture the variability of the measured data very well, producing the lowest average percentage deviation for all compounds studied. The performance of the other models varies with compound and choice of model parameters. The behaviour of ternary mixed inorganic/organic systems was unreliably captured by using a predictive scheme and this was dependent on the composition of the solutes present. For more atmospherically representative higher order systems, entirely predictive schemes performed poorly. It was found that use of the binary data in a relatively simple mixing rule, or modification of an existing thermodynamic model with parameters derived from binary data, was able to accurately capture the surface tension variation with concentration. Thus

  16. Scintillating plate calorimeter optical design

    International Nuclear Information System (INIS)

    McNeil, R.; Fazely, A.; Gunasingha, R.; Imlay, R.; Lim, J.

    1990-01-01

    A major technical challenge facing the builder of a general purpose detector for the SSC is to achieve an optimum design for the calorimeter. Because of its fast response and good energy resolution, scintillating plate sampling calorimeters should be considered as a possible technology option. The work of the Scintillating Plate Calorimeter Collaboration is focused on compensating plate calorimeters. Based on experimental and simulation studies, it is expected that a sampling calorimeter with alternating layers of high-Z absorber (Pb, W, DU, etc.) and plastic scintillator can be made compensating (e/h = 1.00) by suitable choice of the ratio of absorber/scintillator thickness. Two conceptual designs have been pursued by this subsystem collaboration. One is based on lead as the absorber, with read/out of the scintillator plates via wavelength shifter fibers. The other design is based on depleted uranium as the absorber with wavelength shifter (WLS) plate readout. Progress on designs for the optical readout of a compensating scintillator plate calorimeter are presented. These designs include readout of the scintillator plates via wavelength shifter plates or fiber readout. Results from radiation damage studies of the optical components are presented

  17. Radiation damage studies on new liquid scintillators and liquid-core scintillating fibers

    International Nuclear Information System (INIS)

    Golovkin, S.V.

    1994-01-01

    The radiation resistant of some new liquid scintillation and capillaries filled with liquid scintillators has been presented. It was found that scintillation efficiency of the scintillator based on 1-methyl naphthalene with a new R39 only by 10% at the dose of 190 Mrad and the radiation resistance of thin liquid-core scintillating was decreased fibers exceeded 60 Mrad. 35 refs

  18. Scintillators and other particle optical detectors

    International Nuclear Information System (INIS)

    Chipaux, R.

    2011-01-01

    The author reports and comments his researcher career in the field of particle optical detectors. He addresses the cases of organic scintillators (scintillating fibers, liquid scintillators), inorganic scintillators (crystals for electromagnetic calorimetry, crystals for solar neutrino spectroscopy), and Cherenkov Effect detectors. He also reports his works on Cd Te detectors and their modelling

  19. Scintillation 1024-channel hodoscope

    International Nuclear Information System (INIS)

    Kotov, I.V.; Krasnokutskij, R.N.; Kurbakov, V.I.; Shchukin, A.V.

    1993-01-01

    Flow diagram of voltage divider for photomultiplier used in scintillation multichannel hodoscope is described. The suggested diagram of the divider allows to optimize potential distribution at the innput chamber (photocathode - modulator - first dynode) and in the tail segment of the divider (the nineth dynode-anode). Adjustment of high voltage is conducted using multirotational potentiometer switched in series with the divider. Amplifier-limiter with 80 mkA threshold set at voltage comparator is placed at divide plate. Threshold of its sensitivity constitutes 80 mkA. Hodoscope supply system consists of supply sources of comparators (+-6V) four sources of auxiliary supply sources of the last dynodes of photomultipliers and high-voltage source. Current consumption constitutes 25 A by - 6V, 23 A by + 6 V for the whole hodoscope and up to 200 mA from high-voltage source for one plane. Additional charging sources have constant consumption equal to ∼ 20 mA

  20. Encapsulated scintillation detector

    International Nuclear Information System (INIS)

    Toepke, I.L.

    1982-01-01

    A scintillation detector crystal is encapsulated in a hermetically sealed housing having a glass window. The window may be mounted in a ring by a compression seal formed during cooling of the ring and window after heating. The window may be chemically bonded to the ring with or without a compression seal. The ring is welded to the housing along thin weld flanges to reduce the amount of weld heat which must be applied. A thin section is provided to resist the flow of welding heat to the seal between the ring and the window thereby forming a thermal barrier. The thin section may be provided by a groove cut partially through the wall of the ring. A layer of PTFE between the tubular body and the crystal minimizes friction created by thermal expansion. Spring washers urge the crystal towards the window. (author)

  1. Scintillation counter, segmented shield

    International Nuclear Information System (INIS)

    Olson, R.E.; Thumim, A.D.

    1975-01-01

    A scintillation counter, particularly for counting gamma ray photons, includes a massive lead radiation shield surrounding a sample-receiving zone. The shield is disassembleable into a plurality of segments to allow facile installation and removal of a photomultiplier tube assembly, the segments being so constructed as to prevent straight-line access of external radiation through the shield into radiation-responsive areas. Provisions are made for accurately aligning the photomultiplier tube with respect to one or more sample-transmitting bores extending through the shield to the sample receiving zone. A sample elevator, used in transporting samples into the zone, is designed to provide a maximum gamma-receiving aspect to maximize the gamma detecting efficiency. (U.S.)

  2. Properties of scintillator solutes

    International Nuclear Information System (INIS)

    Fluornoy, J.M.

    1998-06-01

    This special report summarizes measurements of the spectroscopic and other properties of the solutes that were used in the preparation of several new liquid scintillators developed at EG and G/Energy Measurements/Santa Barbara Operations (the precursor to Bechtel Nevada/Special Technologies Laboratory) on the radiation-to-light converter program. The data on the individual compounds are presented in a form similar to that used by Prof. Isadore Berlman in his classic handbook of fluorescence spectra. The temporal properties and relative efficiencies of the new scintillators are presented in Table 1, and the efficiencies as a function of wavelength are presented graphically in Figure 1. In addition, there is a descriptive glossary of the abbreviations used herein. Figure 2 illustrates the basic structures of some of the compounds and of the four solvents reported in this summary. The emission spectra generally exhibit more structure than the absorption spectra, with the result that the peak emission wavelength for a given compound may lie several nm away from the wavelength, λ avg , at the geometric center of the emission spectrum. Therefore, the author has chosen to list absorption peaks, λ max , and emission λ avg values in Figures 3--30, as being most illustrative of the differences between the compounds. The compounds, BHTP, BTPB, ADBT, and DPTPB were all developed on this program. P-terphenyl, PBD, and TPB are commercially available blue emitters. C-480 and the other longer-wavelength emitters are laser dyes available commercially from Exciton Corporation. 1 ref., 30 figs

  3. Radiation damage in plastic scintillators

    International Nuclear Information System (INIS)

    Majewski, S.

    1990-01-01

    Results of radiation damage studies in plastic scintillators are reviewed and critically analyzed from the point of view of applications of plastic scintillators in calorimetric detectors for the SSC. Damage to transmission and to fluorescent yield in different conditions is discussed. New directions in R ampersand D are outlined. Several examples are given of the most recent data on the new scintillating materials made with old and new plastics and fluors, which are exhibiting significantly improved radiation resistance. With a present rate of a vigorous R D programme, the survival limits in the vicinity of 100 MRad seem to be feasible within a couple of years

  4. Sub-nanosecond plastic scintillators

    International Nuclear Information System (INIS)

    Lyons, P.B.; Caldwell, S.E.; Hocker, L.P.; Crandall, D.G.; Zagarino, P.A.; Cheng, J.; Tirsell, G.; Hurlbut, C.R.

    1977-01-01

    Quenched plastic scintillators have been developed that yield much faster short decay components and greatly reduced long decay components compared to conventional plastic scintillators. The plastics are produced through the addition of selected quench agents to NE111 plastic scintillator that result in reduced total light output. Eight different agents have been studied. Benzophenone and piperidine are two of the most effective quench agents. Data are presented both for short and long decay components. The plastics are expected to make significant contributions in areas of plasma diagnostics

  5. Sub-nanosecond plastic scintillators

    International Nuclear Information System (INIS)

    Lyons, P.B.; Caldwell, S.E.; Hocker, L.P.; Crandall, D.G.; Zagarino, P.A.; Cheng, J.; Tirsell, G.; Hurlbut, C.R.

    1976-01-01

    Quenched plastic scintillators have been developed that yield much faster short decay components and greatly reduced long decay components compared to conventional plastic scintillators. The plastics are produced through the addition of selected quench agents to NE111 plastic scintillator that result in reduced total light output. Eight different agents have been studied. Benzophenone and piperidine are two of the most effective quench agents. Data are presented both for short and long decay components. The plastics are expected to make significant contributions in areas of plasma diagnostics

  6. Applications of liquid scintillation tubes

    International Nuclear Information System (INIS)

    Broga, D.W.

    1977-01-01

    A new cocktail containing device for liquid scintillation counting, the scintillation tube, consists of a two-layered plastic bag which is heatsealed after the cocktail and sample have been placed in it. It is then placed in a carrying vial and counted in a conventional liquid scintillation counter. These tubes have proved to be a practical and economical alternative to vials. Some of their advantages are elimination of absorption problems, transparency, lower background and higher counting efficiency, low breakage danger and savings in waste disposal costs. Two applications for which the tubes are particularly suitable are the counting of laboratory swipes and urine analysis. (author)

  7. Inorganic-organic Ag-rhodamine 6G hybrid nanorods: "turn on" fluorescent sensors for highly selective detection of Pb2+ ions in aqueous solution.

    Science.gov (United States)

    Tyagi, A K; Ramkumar, Jayshree; Jayakumar, O D

    2012-02-07

    Lead metal ions are of great concern and the monitoring of their concentration in the environment has become extremely important. In the present study, a new inorganic-organic hybrid assay of Ag nanorods (AgNR)-Rhodamine 6G (R6G) was developed for the sensitive and selective determination of Pb(2+) ions in aqueous solutions. To the best of our knowledge there is almost no literature on the use of silver nanorod sensors for determination of lead ions in aqueous solutions. The sensor is developed by the coating of R6G on the surface of AgNRs. The sensing is based on the photoluminescence of R6G. The sensor was rapid as the measurements were carried out within 3 min of addition of the test solution to the AgNR-R6G hybrid. Moreover, the system showed excellent stability at tested concentration levels of Pb(2+) ions. The naked eye detection of the colour was possible with 1 mg L(-1) of Pb(2+) ions. The present method has a detection limit of 50 μg L(-1) of Pb(2+) (for a signal/noise (S/N) ratio > 3). The selectivity toward Pb(2+) ions against other metal ions was improved using chelating agents. The proposed method was validated by analysis using different techniques.

  8. Transition metal modified and partially calcined inorganic-organic pillared clays for the adsorption of salicylic acid, clofibric acid, carbamazepine, and caffeine from water.

    Science.gov (United States)

    Cabrera-Lafaurie, Wilman A; Román, Félix R; Hernández-Maldonado, Arturo J

    2012-11-15

    Pharmaceutical and Personal Care Products (PPCPs) are considered emerging contaminants, and their efficient removal from water is going to be a challenging endeavor. Microporous adsorbent materials, including pillared clays, could offer a potential solution if tailored properly. Although pillared clays have been employed previously for the removal of organics, the effective removal of PPCPs will only be possible if their surface and textural properties are manipulated from the bottom-up. This work presents the use of modified inorganic-organic pillared clays (IOCs) for the adsorption of salicylic acid, clofibric acid, carbamazepine, and caffeine. The IOCs have been modified with Co(2+), Cu(2+), or Ni(2+) to induce complexation-like adsorbate-adsorbent interactions at ambient conditions, in an attempt to provide an efficient and yet reversible driving force in the sub-ppm concentration range. Furthermore, the IOCs were partially calcined to increase effective surface area by an order of magnitude while preserving some hydrophobicity. In general, the Ni(2+) IOCs exhibited the greatest interaction with salicylic and clofibric acids, respectively, while the Co(2+) adsorbents excelled at adsorbing caffeine at low concentrations. All of the metal-modified IOCs showed comparable adsorption capacities for the case of carbamazepine, probably due to the lack of availability of particular functional groups in this adsorbate. Copyright © 2012 Elsevier Inc. All rights reserved.

  9. Strong room-temperature ultraviolet to red excitons from inorganic organic-layered perovskites, (MX4 (M=Pb, Sn, Hg; X=I-, Br-)

    Science.gov (United States)

    Ahmad, Shahab; Prakash, G. Vijaya

    2014-01-01

    Many varieties of layered inorganic-organic (IO) perovskite of type (MX4 (where R: organic moiety, M: divalent metal, and X: halogen) were successfully fabricated and characterized. X-ray diffraction data suggest that these inorganic and organic structures are alternatively stacked up along c-axis, where inorganic mono layers are of extended corner-shared MX6 octahedra and organic spacers are the bi-layers of organic entities. These layered perovskites show unusual room-temperature exciton absorption and photoluminescence due to the quantum and dielectric confinement-induced enhancement in the exciton binding energies. A wide spectral range of optical exciton tunability (350 to 600 nm) was observed experimentally from systematic compositional variation in (i) divalent metal ions (M=Pb, Sn, Hg), (ii) halides (X=I and Br-), and (iii) organic moieties (R). Specific photoluminescence features are due to the structure of the extended MX42- network and the eventual electronic band structure. The compositionally dependent photoluminescence of these IO hybrids could be useful in various photonic and optoelectronic devices.

  10. 3,6-Carbazole vs 2,7-carbazole: A comparative study of hole-transporting polymeric materials for inorganic-organic hybrid perovskite solar cells.

    Science.gov (United States)

    Li, Wei; Otsuka, Munechika; Kato, Takehito; Wang, Yang; Mori, Takehiko; Michinobu, Tsuyoshi

    2016-01-01

    The ever increasing demand for clean energy has encouraged researchers to intensively investigate environmentally friendly photovoltaic devices. Inorganic-organic hybrid perovskite solar cells (PSCs) are very promising due to their potentials of easy fabrication processes and high power conversion efficiencies (PCEs). Designing hole-transporting materials (HTMs) is one of the key factors in achieving the high PCEs of PSCs. We now report the synthesis of two types of carbazole-based polymers, namely 3,6-Cbz-EDOT and 2,7-Cbz-EDOT, by Stille polycondensation. Despite the same chemical composition, 3,6-Cbz-EDOT and 2,7-Cbz-EDOT displayed different optical and electrochemical properties due to the different connectivity mode of the carbazole unit. Therefore, their performances as hole-transporting polymeric materials in the PSCs were also different. The device based on 2,7-Cbz-EDOT showed better photovoltaic properties with the PCE of 4.47% than that based on 3,6-Cbz-EDOT. This could be due to its more suitable highest occupied molecular orbital (HOMO) level and higher hole mobility.

  11. Inorganic-organic hybrid coatings on stainless steel by layer-by-layer deposition and surface-initiated atom-transfer-radical polymerization for combating biocorrosion.

    Science.gov (United States)

    Yuan, S J; Pehkonen, S O; Ting, Y P; Neoh, K G; Kang, E T

    2009-03-01

    To improve the biocorrosion resistance of stainless steel (SS) and to confer the bactericidal function on its surface for inhibiting bacterial adhesion and biofilm formation, well-defined inorganic-organic hybrid coatings, consisting of the inner compact titanium oxide multilayers and outer dense poly(vinyl-N-hexylpyridinium) brushes, were successfully developed. Nanostructured titanium oxide multilayer coatings were first built up on the SS substrates via the layer-by-layer sol-gel deposition process. The trichlorosilane coupling agent, containing the alkyl halide atom-transfer-radical polymerization (ATRP) initiator, was subsequently immobilized on the titanium oxide coatings for surface-initiated ATRP of 4-vinylpyridine (4VP). The pyridium nitrogen moieties of the covalently immobilized 4VP polymer, or P(4VP), brushes were quaternized with hexyl bromide to produce a high concentration of quaternary ammonium salt on the SS surfaces. The excellent antibacterial efficiency of the grafted polycations, poly(vinyl-N-pyridinium bromide), was revealed by viable cell counts and atomic force microscopy images of the surface. The effectiveness of the hybrid coatings in corrosion protection was verified by the Tafel plot and electrochemical impedance spectroscopy measurements.

  12. Room-temperature polar order in [NH4][Cd(HCOO)3]--a hybrid inorganic-organic compound with a unique perovskite architecture.

    Science.gov (United States)

    Gómez-Aguirre, L C; Pato-Doldán, B; Stroppa, A; Yáñez-Vilar, S; Bayarjargal, L; Winkler, B; Castro-García, S; Mira, J; Sánchez-Andújar, M; Señarís-Rodríguez, M A

    2015-03-02

    We report on the hybrid inorganic-organic ammonium compound [NH4][Cd(HCOO)3], which displays a most unusual framework structure: instead of the expected 4(9)·6(6) topology, it shows an ABX3 perovskite architecture with the peculiarity and uniqueness (among all the up-to-date reported hybrid metal formates) that the Cd ions are connected only by syn-anti formate bridges, instead of anti-anti ones. This change of the coordination mode of the formate ligand is thus another variable that can provide new possibilities for tuning the properties of these versatile functional metal-organic framework materials. The room-temperature crystal structure of [NH4][Cd(HCOO)3] is noncentrosymmetric (S.G.: Pna21) and displays a polar axis. DFT calculations and symmetry mode analysis show that the rather large polarization arising from the off-center shift of the ammonium cations in the cavities (4.33 μC/cm(2)) is partially canceled by the antiparallel polarization coming from the [Cd(HCOO)3](-) framework, thus resulting in a net polarization of 1.35 μC/cm(2). As shown by second harmonic generation studies, this net polarization can be greatly increased by applying pressure (Pmax = 14 GPa), an external stimulus that, in turn, induces the appearance of new structural phases, as confirmed by Raman spectroscopy.

  13. Temperature dependence of plastic scintillators

    Science.gov (United States)

    Peralta, L.

    2018-03-01

    Plastic scintillator detectors have been studied as dosimeters, since they provide a cost-effective alternative to conventional ionization chambers. Several articles have reported undesired response dependencies on beam energy and temperature, which provides the motivation to determine appropriate correction factors. In this work, we studied the light yield temperature dependency of four plastic scintillators, BCF-10, BCF-60, BC-404, RP-200A and two clear fibers, BCF-98 and SK-80. Measurements were made using a 50 kVp X-ray beam to produce the scintillation and/or radioluminescence signal. The 0 to 40 °C temperature range was scanned for each scintillator, and temperature coefficients were obtained.

  14. Photon statistics in scintillation crystals

    Science.gov (United States)

    Bora, Vaibhav Joga Singh

    Scintillation based gamma-ray detectors are widely used in medical imaging, high-energy physics, astronomy and national security. Scintillation gamma-ray detectors are eld-tested, relatively inexpensive, and have good detection eciency. Semi-conductor detectors are gaining popularity because of their superior capability to resolve gamma-ray energies. However, they are relatively hard to manufacture and therefore, at this time, not available in as large formats and much more expensive than scintillation gamma-ray detectors. Scintillation gamma-ray detectors consist of: a scintillator, a material that emits optical (scintillation) photons when it interacts with ionization radiation, and an optical detector that detects the emitted scintillation photons and converts them into an electrical signal. Compared to semiconductor gamma-ray detectors, scintillation gamma-ray detectors have relatively poor capability to resolve gamma-ray energies. This is in large part attributed to the "statistical limit" on the number of scintillation photons. The origin of this statistical limit is the assumption that scintillation photons are either Poisson distributed or super-Poisson distributed. This statistical limit is often dened by the Fano factor. The Fano factor of an integer-valued random process is dened as the ratio of its variance to its mean. Therefore, a Poisson process has a Fano factor of one. The classical theory of light limits the Fano factor of the number of photons to a value greater than or equal to one (Poisson case). However, the quantum theory of light allows for Fano factors to be less than one. We used two methods to look at the correlations between two detectors looking at same scintillation pulse to estimate the Fano factor of the scintillation photons. The relationship between the Fano factor and the correlation between the integral of the two signals detected was analytically derived, and the Fano factor was estimated using the measurements for SrI2:Eu, YAP

  15. Radiation Damage in Scintillating Crystals

    CERN Document Server

    Zhu Ren Yuan

    1998-01-01

    Crystal Calorimetry in future high energy physics experiments faces a new challenge to maintain its precision in a hostile radiation environment. This paper discusses the effects of radiation damage in scintillating crystals, and concludes that the predominant radiation damage effect in crystal scintillators is the radiation induced absorption, or color center formation, not the loss of the scintillation light yield. The importance of maintaining crystal's light response uniformity and the feasibility to build a precision crystal calorimeter under radiation are elaborated. The mechanism of the radiation damage in scintillating crystals is also discussed. While the damage in alkali halides is found to be caused by the oxygen or hydroxyl contamination, it is the structure defects, such as oxygen vacancies, cause damage in oxides. Material analysis methods used to reach these conclusions are presented in details.

  16. Significance of the double-layer capacitor effect in polar rubbery dielectrics and exceptionally stable low-voltage high transconductance organic transistors.

    Science.gov (United States)

    Wang, Chao; Lee, Wen-Ya; Kong, Desheng; Pfattner, Raphael; Schweicher, Guillaume; Nakajima, Reina; Lu, Chien; Mei, Jianguo; Lee, Tae Hoon; Wu, Hung-Chin; Lopez, Jeffery; Diao, Ying; Gu, Xiaodan; Himmelberger, Scott; Niu, Weijun; Matthews, James R; He, Mingqian; Salleo, Alberto; Nishi, Yoshio; Bao, Zhenan

    2015-12-14

    Both high gain and transconductance at low operating voltages are essential for practical applications of organic field-effect transistors (OFETs). Here, we describe the significance of the double-layer capacitance effect in polar rubbery dielectrics, even when present in a very low ion concentration and conductivity. We observed that this effect can greatly enhance the OFET transconductance when driven at low voltages. Specifically, when the polar elastomer poly(vinylidene fluoride-co-hexafluoropropylene) (e-PVDF-HFP) was used as the dielectric layer, despite a thickness of several micrometers, we obtained a transconductance per channel width 30 times higher than that measured for the same organic semiconductors fabricated on a semicrystalline PVDF-HFP with a similar thickness. After a series of detailed experimental investigations, we attribute the above observation to the double-layer capacitance effect, even though the ionic conductivity is as low as 10(-10) S/cm. Different from previously reported OFETs with double-layer capacitance effects, our devices showed unprecedented high bias-stress stability in air and even in water.

  17. Significance of the double-layer capacitor effect in polar rubbery dielectrics and exceptionally stable low-voltage high transconductance organic transistors

    Science.gov (United States)

    Wang, Chao; Lee, Wen-Ya; Kong, Desheng; Pfattner, Raphael; Schweicher, Guillaume; Nakajima, Reina; Lu, Chien; Mei, Jianguo; Lee, Tae Hoon; Wu, Hung-Chin; Lopez, Jeffery; Diao, Ying; Gu, Xiaodan; Himmelberger, Scott; Niu, Weijun; Matthews, James R.; He, Mingqian; Salleo, Alberto; Nishi, Yoshio; Bao, Zhenan

    2015-01-01

    Both high gain and transconductance at low operating voltages are essential for practical applications of organic field-effect transistors (OFETs). Here, we describe the significance of the double-layer capacitance effect in polar rubbery dielectrics, even when present in a very low ion concentration and conductivity. We observed that this effect can greatly enhance the OFET transconductance when driven at low voltages. Specifically, when the polar elastomer poly(vinylidene fluoride-co-hexafluoropropylene) (e-PVDF-HFP) was used as the dielectric layer, despite a thickness of several micrometers, we obtained a transconductance per channel width 30 times higher than that measured for the same organic semiconductors fabricated on a semicrystalline PVDF-HFP with a similar thickness. After a series of detailed experimental investigations, we attribute the above observation to the double-layer capacitance effect, even though the ionic conductivity is as low as 10–10 S/cm. Different from previously reported OFETs with double-layer capacitance effects, our devices showed unprecedented high bias-stress stability in air and even in water. PMID:26658331

  18. Alkali metal hafnium oxide scintillators

    Science.gov (United States)

    Bourret-Courchesne, Edith; Derenzo, Stephen E.; Taylor, Scott Edward

    2018-05-08

    The present invention provides for a composition comprising an inorganic scintillator comprising an alkali metal hafnate, optionally cerium-doped, having the formula A2HfO3:Ce; wherein A is an alkali metal having a valence of 1, such as Li or Na; and the molar percent of cerium is 0% to 100%. The alkali metal hafnate are scintillators and produce a bright luminescence upon irradiation by a suitable radiation.

  19. Ionospheric Scintillation Effects on GPS

    Science.gov (United States)

    Steenburgh, R. A.; Smithtro, C.; Groves, K.

    2007-12-01

    . Ionospheric scintillation of Global Positioning System (GPS) signals threatens navigation and military operations by degrading performance or making GPS unavailable. Scintillation is particularly active, although not limited to, a belt encircling the earth within 20 degrees of the geomagnetic equator. As GPS applications and users increases, so does the potential for detrimental impacts from scintillation. We examined amplitude scintillation data spanning seven years from Ascension Island, U.K.; Ancon, Peru; and Antofagasta, Chile in the Atlantic/Americas longitudinal sector at as well as data from Parepare, Indonesia; Marak Parak, Malaysia; Pontianak, Indonesia; Guam; and Diego Garcia, U.K.; in the Pacific longitudinal sector. From these data, we calculate percent probability of occurrence of scintillation at various intensities described by the S4 index. Additionally, we determine Dilution of Precision at one minute resolution. We examine diurnal, seasonal and solar cycle characteristics and make spatial comparisons. In general, activity was greatest during the equinoxes and solar maximum, although scintillation at Antofagasta, Chile was higher during 1998 rather than at solar maximum.

  20. Scintillation counter based radiation dosimeter

    International Nuclear Information System (INIS)

    Shin, Jeong Hyun

    2009-02-01

    The average human exposure per year is about 240mrem which is come from Radon and human body and terrestrial and cosmic radiation and man-made source. Specially radiation exposure through air from environmental radiation sources is 80mrem/yr(= 0.01mR/hr) which come from Terrestrial and cosmic radiation. Radiation dose is defined as energy deposit/mass. There are two major methods to detect radiation. First method is the energy integration using Air equivalent material like GM counter wall material. Second method is the spectrum to dose conversion method using NaI(Tl), HPGe. These two methods are using generally to detect radiation. But these methods are expensive. So we need new radiation detection method. The research purpose is the development of economical environmental radiation dosimeter. This system consists of Plastic/Inorganic scintillator and Si photo-diode based detector and counting based circuitry. So count rate(cps) can be convert to air exposure rate(R/hr). There are three major advantages in this system. First advantages is no high voltage power supply like GM counter. Second advantage is simple electronics. Simple electronics system can be achieved by Air-equivalent scintillation detector with Al filter for the same detection efficiency vs E curve. From former two advantages, we can know the most important advantages of the this system. Third advantage is economical system. The price of typical GM counter is about $1000. But the price of our system is below $100 because of plastic scintillator and simple electronics. The role of scintillation material is emitting scintillation which is the flash of light produced in certain materials when they absorb ionizing radiation. Plastic scintillator is organic scintillator which is kind of hydrocarbons. The special point are cheap price, large size production(∼ton), moderate light output, fast light emission(ns). And the role of Al filter is equalizing counting efficiency of air and scintillator for

  1. Exciton generation/dissociation/charge-transfer enhancement in inorganic/organic hybrid solar cells by robust single nanocrystalline LnPxOy (Ln = Eu, Y) doping.

    Science.gov (United States)

    Jin, Xiao; Sun, Weifu; Chen, Zihan; Wei, Taihuei; Chen, Chuyang; He, Xingdao; Yuan, Yongbiao; Li, Yue; Li, Qinghua

    2014-06-11

    Low-temperature solution-processed photovoltaics suffer from low efficiencies because of poor exciton or electron-hole transfer. Inorganic/organic hybrid solar cell, although still in its infancy, has attracted great interest thus far. One of the promising ways to enhance exciton dissociation or electron-hole transport is the doping of lanthanide phosphate ions. However, the underlying photophysical mechanism remains poorly understood. Herein, by applying femtosecond transient absorption spectroscopy, we successfully distinguished hot electron, less energetic electron, hole transport from electron-hole recombination. Concrete evidence has been provided that lanthanide phosphate doping improves the efficiency of both hot electron and "less energetic" electron transfers from donor to acceptor, but the hole transport almost remains unchanged. In particular, the hot electron transfer lifetime was shortened from 30.2 to 12.7 ps, that is, more than 60% faster than pure TiO2 acceptor. Such improvement was ascribed to the facts that the conduction band (CB) edge energy level of TiO2 has been elevated by 0.2 eV, while the valence band level almost remains unchanged, thus not only narrowing the energy offset between CB levels of TiO2 and P3HT, but also meanwhile enlarging the band gap of TiO2 itself that permits one to inhibit electron-hole recombination within TiO2. Consequently, lanthanide phosphate doped TiO2/P3HT bulk-heterojunction solar cell has been demonstrated to be a promising hybrid solar cell, and a notable power conversion efficiency of 2.91% is therefore attained. This work indicates that lanthanide compound ions can efficiently facilitate exciton generation, dissociation, and charge transport, thus enhancing photovoltaic performance.

  2. Synthesis, crystal structure and growth of a new inorganic- organic hybrid compound for nonlinear optical applications: Aquadiiodo (3-aminopropanoic acid) cadmium (II)

    Science.gov (United States)

    Boopathi, K.; Babu, S. Moorthy; Jagan, R.; Ramasamy, P.

    2017-12-01

    The new inorganic-organic hybrid material aquadiiodo (3-aminopropanoic acid) cadmium (II) [ADI (3-AP) Cd] has been successfully synthesized and good quality crystals have been grown by slow evaporation solution technique. The structure was determined by single crystal X-ray diffraction at room temperature. The compound crystallizes in monoclinic crystal system with centro symmetric space group P21/c and four molecules in the unit cell. The structure of the title compound was further confirmed by 1H and 13C nuclear magnetic resonance spectral analysis. FT-IR spectroscopy was used to confirm the presence of various functional groups in the compound. The transmittance and optical parameters of the crystal were studied by UV- Visible-NIR spectroscopy. The thermal stability of the grown crystal was evaluated using thermogravimetric and differential thermal analyses. Mechanical hardness has been identified by Vickers micro hardness study and work hardening coefficient was calculated. Dielectric measurement was carried out as a function of frequency and results are discussed. The growth mechanism of the crystal was assessed by chemical etching studies. The third-order nonlinear optical susceptibility of [ADI (3-AP) Cd] was derived using the Z-scan technique, and it was 3.24955 × 10-8 esu. The positive nonlinear refractive index 2.48505 × 10-11 m2/W, is an indication of self-defocusing optical nonlinearity of the sample. It is believed that the [ADI (3-AP) Cd] is a promising new candidate for developing efficient nonlinear optical and optical power limiting devices.

  3. Keggin type inorganic-organic hybrid material containing Mn(II) monosubstituted phosphotungstate and S-(+)-sec-butyl amine: Synthesis and characterization

    Energy Technology Data Exchange (ETDEWEB)

    Patel, Ketan [Chemistry Department, Faculty of Science, M.S. University of Baroda, Vadodara 390 002 (India); Patel, Anjali, E-mail: aupatel_chem@yahoo.com [Chemistry Department, Faculty of Science, M.S. University of Baroda, Vadodara 390 002 (India)

    2012-02-15

    Graphical abstract: A new organic-inorganic hybrid material containing Keggin type manganese substituted phosphotungstate and S-(+)-sec-butyl amine was synthesized and systematically characterized. Highlights: Black-Right-Pointing-Pointer New hybrid material comprising Mn substituted phosphotungstate (PW{sub 11}Mn) and S-(+)-sec-butyl amine (SBA) was synthesized. Black-Right-Pointing-Pointer The spectral studies reveal the attachment of SBA to the PW{sub 11}Mn without any distortion of structure. Black-Right-Pointing-Pointer The synthesized material comprises chirality. Black-Right-Pointing-Pointer The synthesized hybrid material can be used as a heterogeneous catalyst for carrying out asymmetric synthesis. -- Abstract: A new inorganic-organic POM-based hybrid material comprising Keggin type mono manganese substituted phosphotungstate and enantiopure S-(+)-sec-butyl amine was synthesized in an aqueous media by simple ligand substitution method. The synthesized hybrid material was systematically characterized in solid as well as solution by various physicochemical techniques such as elemental analysis, TGA, UV-vis, FT-IR, ESR and multinuclear solution NMR ({sup 31}P, {sup 1}H, {sup 13}C). The presence of chirality in the synthesized material was confirmed by CD spectroscopy and polarimeter. The above study reveals the attachment of S-(+)-sec-butyl amine to Keggin type mono manganese substituted phosphotungstate through N {yields} Mn bond. It also indicates the retainment of Keggin unit and presence of chirality in the synthesized material. An attempt was made to use the synthesized material as a heterogeneous catalyst for carrying out aerobic asymmetric oxidation of styrene using molecular oxygen. The catalyst shows the potential of being used as a stable recyclable catalytic material after simple regeneration without significant loss in conversion.

  4. Polycarboxylic acids as network modifiers for water durability improvement of inorganic-organic hybrid tin-silico-phosphate low-melting glasses

    International Nuclear Information System (INIS)

    Menaa, Bouzid; Mizuno, Megumi; Takahashi, Masahide; Tokuda, Yomei; Yoko, Toshinobu

    2006-01-01

    We investigated the water durability of the inorganic-organic hybrid tin-silico-phosphate glasses Me 2 SiO-SnO-P 2 O 5 (Me designs the organic methyl group) doped with organic acids (salicylic acid (SA), tartaric acid (TA), citric acid (Canada) and butane tetracarboxylic acid (BTCA)) containing one or more of carboxylic groups per molecule. The structure, thermal properties and durability of the final glasses obtained via a non-aqueous acid-base reaction were discussed owing to the nature and the concentration of the acid added. 29 Si magic angle spinning (MAS) NMR and 31 P MAS NMR spectra, respectively, showed clearly a modification of the network in the host glass matrix of the Me 2 SiO-SnO-P 2 O 5 system. The polycondensation enhancement to form -P-O-Si-O-P- linkages (PSP) and the increase of the Q 2 unit (two bridging oxygens per phosphorus atom) over the Q 3 unit (three bridging oxygens per phosphorus atom) as a function of the acid in the order SA 2 SiO-SnO-P 2 O 5 matrix. In addition, this structural change is accompanied by a decrease of the coefficient of thermal expansion and an increase of the water durability of the glasses with the acids containing a large number of carboxylic groups per molecule. The presence of carboxylic groups of the acid acting as network modifier may retard the movement of water molecules through the glasses due to the steric hindrance strengthening the PSP connections in a chain-like structure

  5. Neutrons detection by scintillation; Detection de neutrons par scintillations

    Energy Technology Data Exchange (ETDEWEB)

    Giraudon, J [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1955-01-15

    The absence of charge of neutrons and their elevated penetration power make difficult their detection. Techniques vary otherwise with the energy of the particle. The author proposes the realization of a scintillation detector with a big volume of liquid scintillator and containing boron for the detection of slowing-down neutrons in the domain of intermediate energies from 1 to 10{sup 5} eV about. (M.B.) [French] L'absence de charge du neutron et son pouvoir de penetration eleve rendent difficile sa detection. Les techniques par ailleurs varient avec l'energie de cette particule. L'auteur propose la realisation d'un detecteur a scintillations comprenant un grand volume de scintillateur liquide et contenant du bore pour la detection des neutrons en ralentissement dans le domaine des energies intermediaires de 1 a 10{sup 5} eV environ. (M.B.)

  6. Cherenkov and scintillation light separation in organic liquid scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Caravaca, J.; Descamps, F.B.; Land, B.J.; Orebi Gann, G.D. [University of California, Berkeley, CA (United States); Lawrence Berkeley National Laboratory, Berkeley, CA (United States); Yeh, M. [Brookhaven National Laboratory, Upton, NY (United States)

    2017-12-15

    The CHErenkov/Scintillation Separation experiment (CHESS) has been used to demonstrate the separation of Cherenkov and scintillation light in both linear alkylbenzene (LAB) and LAB with 2 g/L of PPO as a fluor (LAB/PPO). This is the first successful demonstration of Cherenkov light detection from the more challenging LAB/PPO cocktail and improves on previous results for LAB. A time resolution of 338 ± 12 ps FWHM results in an efficiency for identifying Cherenkov photons in LAB/PPO of 70 ± 3% and 63 ± 8% for time- and charge-based separation, respectively, with scintillation contamination of 36 ± 5% and 38 ± 4. LAB/PPO data is consistent with a rise time of τ{sub r} = 0.72 ± 0.33 ns. (orig.)

  7. Cherenkov and scintillation light separation in organic liquid scintillators

    International Nuclear Information System (INIS)

    Caravaca, J.; Descamps, F.B.; Land, B.J.; Orebi Gann, G.D.; Yeh, M.

    2017-01-01

    The CHErenkov/Scintillation Separation experiment (CHESS) has been used to demonstrate the separation of Cherenkov and scintillation light in both linear alkylbenzene (LAB) and LAB with 2 g/L of PPO as a fluor (LAB/PPO). This is the first successful demonstration of Cherenkov light detection from the more challenging LAB/PPO cocktail and improves on previous results for LAB. A time resolution of 338 ± 12 ps FWHM results in an efficiency for identifying Cherenkov photons in LAB/PPO of 70 ± 3% and 63 ± 8% for time- and charge-based separation, respectively, with scintillation contamination of 36 ± 5% and 38 ± 4. LAB/PPO data is consistent with a rise time of τ r = 0.72 ± 0.33 ns. (orig.)

  8. Neutrons detection by scintillation; Detection de neutrons par scintillations

    Energy Technology Data Exchange (ETDEWEB)

    Giraudon, J. [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1955-01-15

    The absence of charge of neutrons and their elevated penetration power make difficult their detection. Techniques vary otherwise with the energy of the particle. The author proposes the realization of a scintillation detector with a big volume of liquid scintillator and containing boron for the detection of slowing-down neutrons in the domain of intermediate energies from 1 to 10{sup 5} eV about. (M.B.) [French] L'absence de charge du neutron et son pouvoir de penetration eleve rendent difficile sa detection. Les techniques par ailleurs varient avec l'energie de cette particule. L'auteur propose la realisation d'un detecteur a scintillations comprenant un grand volume de scintillateur liquide et contenant du bore pour la detection des neutrons en ralentissement dans le domaine des energies intermediaires de 1 a 10{sup 5} eV environ. (M.B.)

  9. Scintillation-Hardened GPS Receiver

    Science.gov (United States)

    Stephens, Donald R.

    2015-01-01

    CommLargo, Inc., has developed a scintillation-hardened Global Positioning System (GPS) receiver that improves reliability for low-orbit missions and complies with NASA's Space Telecommunications Radio System (STRS) architecture standards. A software-defined radio (SDR) implementation allows a single hardware element to function as either a conventional radio or as a GPS receiver, providing backup and redundancy for platforms such as the International Space Station (ISS) and high-value remote sensing platforms. The innovation's flexible SDR implementation reduces cost, weight, and power requirements. Scintillation hardening improves mission reliability and variability. In Phase I, CommLargo refactored an open-source GPS software package with Kalman filter-based tracking loops to improve performance during scintillation and also demonstrated improved navigation during a geomagnetic storm. In Phase II, the company generated a new field-programmable gate array (FPGA)-based GPS waveform to demonstrate on NASA's Space Communication and Navigation (SCaN) test bed.

  10. Development of radiation hard scintillators

    International Nuclear Information System (INIS)

    Markley, F.; Woods, D.; Pla-Dalmau, A.; Foster, G.; Blackburn, R.

    1992-05-01

    Substantial improvements have been made in the radiation hardness of plastic scintillators. Cylinders of scintillating materials 2.2 cm in diameter and 1 cm thick have been exposed to 10 Mrads of gamma rays at a dose rate of 1 Mrad/h in a nitrogen atmosphere. One of the formulations tested showed an immediate decrease in pulse height of only 4% and has remained stable for 12 days while annealing in air. By comparison a commercial PVT scintillator showed an immediate decrease of 58% and after 43 days of annealing in air it improved to a 14% loss. The formulated sample consisted of 70 parts by weight of Dow polystyrene, 30 pbw of pentaphenyltrimethyltrisiloxane (Dow Corning DC 705 oil), 2 pbw of p-terphenyl, 0.2 pbw of tetraphenylbutadiene, and 0.5 pbw of UVASIL299LM from Ferro

  11. Nanophosphor composite scintillator with a liquid matrix

    Science.gov (United States)

    McKigney, Edward Allen; Burrell, Anthony Keiran; Bennett, Bryan L.; Cooke, David Wayne; Ott, Kevin Curtis; Bacrania, Minesh Kantilal; Del Sesto, Rico Emilio; Gilbertson, Robert David; Muenchausen, Ross Edward; McCleskey, Thomas Mark

    2010-03-16

    An improved nanophosphor scintillator liquid comprises nanophosphor particles in a liquid matrix. The nanophosphor particles are optionally surface modified with an organic ligand. The surface modified nanophosphor particle is essentially surface charge neutral, thereby preventing agglomeration of the nanophosphor particles during dispersion in a liquid scintillator matrix. The improved nanophosphor scintillator liquid may be used in any conventional liquid scintillator application, including in a radiation detector.

  12. Improvements to well scintillation counters

    International Nuclear Information System (INIS)

    Farukhi, M.R.; Mataraza, G.A.; Wimer, O.D.

    1977-01-01

    This invention relates to the field of ionising radiation detection. It concerns in particular scintillation detectors of the type that is commonly used in conjunction with a photomultiplier tube and that is used for monitoring radiation, for instance in the clinical measurements of isotopes. This invention enables well scintillation counters to be made, characterised by a high efficiency in measuring the thindown rate of radio-pharmaceutical solutions and to resolve the distribution of energy emanating from the radioactive source. It particularly consists in improving the uniformity of the luminous efficiency, the quality of the resolution and the efficiency whilst improving the reception of light [fr

  13. Magnetic fields and scintillator performance

    International Nuclear Information System (INIS)

    Green, D.; Ronzhin, A.; Hagopian, V.

    1995-06-01

    Experimental data have shown that the light output of a scintillator depends on the magnitude of the externally applied magnetic fields, and that this variation can affect the calorimeter calibration and possibly resolution. The goal of the measurements presented here is to study the light yield of scintillators in high magnetic fields in conditions that are similar to those anticipated for the LHC CMS detector. Two independent measurements were performed, the first at Fermilab and the second at the National High Magnetic Field Laboratory at Florida State University

  14. Development of scintillating fiber tracker

    International Nuclear Information System (INIS)

    Ishikawa, Shuzo; Kawai, Toshihide; Kozaki, Tetsuo

    1995-01-01

    In order to use thin scintillating fiber (diameter 500 micron) as a particle tracking detector, we have developed a method to construct precise multi-layer scintillating fiber sheets. We have also developed dedicated machines for this purpose. This paper presents the details of the method and the machines. Using these machines, we have produced fiber sheets for CERN WA95/CHORUS, which intend to detect a neutrino oscillation in the νμ-ντ channel using Hybrid Emulsion Set-up. Fiber Trackers are used as a vertex detector which support the neutrino event location in the nuclear emulsion target. (author)

  15. Time resolution research in liquid scintillating detection

    International Nuclear Information System (INIS)

    He Hongkun; Shi Haoshan

    2006-01-01

    The signal processing design method is introduced into liquid scintillating detection system design. By analyzing the signal of liquid scintillating detection, improving time resolution is propitious to upgrade efficiency of detecting. The scheme of realization and satisfactory experiment data is demonstrated. Besides other types of liquid scintillating detection is the same, just using more high speed data signal processing techniques and elements. (authors)

  16. Composite scintillators for detection of ionizing radiation

    Science.gov (United States)

    Dai, Sheng [Knoxville, TN; Stephan, Andrew Curtis [Knoxville, TN; Brown, Suree S [Knoxville, TN; Wallace, Steven A [Knoxville, TN; Rondinone, Adam J [Knoxville, TN

    2010-12-28

    Applicant's present invention is a composite scintillator having enhanced transparency for detecting ionizing radiation comprising a material having optical transparency wherein said material comprises nano-sized objects having a size in at least one dimension that is less than the wavelength of light emitted by the composite scintillator wherein the composite scintillator is designed to have selected properties suitable for a particular application.

  17. Photonic crystal scintillators and methods of manufacture

    Science.gov (United States)

    Torres, Ricardo D.; Sexton, Lindsay T.; Fuentes, Roderick E.; Cortes-Concepcion, Jose

    2015-08-11

    Photonic crystal scintillators and their methods of manufacture are provided. Exemplary methods of manufacture include using a highly-ordered porous anodic alumina membrane as a pattern transfer mask for either the etching of underlying material or for the deposition of additional material onto the surface of a scintillator. Exemplary detectors utilizing such photonic crystal scintillators are also provided.

  18. Synthesis of plastic scintillation microspheres: Evaluation of scintillators

    International Nuclear Information System (INIS)

    Santiago, L.M.; Bagán, H.; Tarancón, A.; Garcia, J.F.

    2013-01-01

    The use of plastic scintillation microspheres (PSm) appear to be an alternative to liquid scintillation for the quantification of alpha and beta emitters because it does not generate mixed wastes after the measurement (organic and radioactive). In addition to routine radionuclide determinations, PSm can be used for further applications, e.g. for usage in a continuous monitoring equipment, for measurements of samples with a high salt concentration and for an extractive scintillation support which permits the separation, pre-concentration and measurement of the radionuclides without additional steps of elution and sample preparation. However, only a few manufacturers provide PSm, and the low number of regular suppliers reduces its availability and restricts the compositions and sizes available. In this article, a synthesis method based on the extraction/evaporation methodology has been developed and successfully used for the synthesis of plastic scintillation microspheres. Seven different compositions of plastic scintillation microspheres have been synthesised; PSm1 with polystyrene, PSm2 with 2,5-Diphenyloxazol(PPO), PSm3 with p-terphenyl (pT), PSm4 with PPO and 1,4-bis(5-phenyloxazol-2-yl) (POPOP), PSm5 pT and (1,4-bis [2-methylstyryl] benzene) (Bis-MSB), PSm6 with PPO, POPOP and naphthalene and PSm7 with pT, Bis-MSB and naphthalene. The synthesised plastic scintillation microspheres have been characterised in terms of their morphology, detection capabilities and alpha/beta separation capacity. The microspheres had a median diameter of approximately 130 μm. Maximum detection efficiency values were obtained for the PSm4 composition as follows 1.18% for 3 H, 51.2% for 14 C, 180.6% for 90 Sr/ 90 Y and 76.7% for 241 Am. Values of the SQP(E) parameter were approximately 790 for PSm4 and PSm5. These values show that the synthesised PSm exhibit good scintillation properties and that the spectra are at channel numbers higher than in commercial PSm. Finally, the addition

  19. Shock-resistant scintillation detector

    International Nuclear Information System (INIS)

    Novak, W.P.

    1979-01-01

    A unique scintillation detector unit is disclosed which employs a special light transfer and reflector means that encases and protects the scintillator crystal against high g forces. The light transfer means comprises a flexible silicon rubber optical material bonded between the crystal and the optical window and having an axial thickness sufficient to allow the scintillator to move axially inside the container under high g forces without destroying the bonds. The reflector means comprises a soft elastic silicone rubber sleeve having a multiplicity of closely arranged tapered protrusions radiating toward and engaging the periphery of the scintillator crystal to cushion shocks effectively and having a reflective material, such as aluminum oxide powder, in the spaces between the protrusions. The reflector means provides improved shock absorption because of the uniform support and cushioning action of the protrusions and also provides the detector with high efficiency. The silicon rubber composition is specially compounded to include a large amount of aluminum oxide which enables the rubber to function effectively as a light reflector

  20. Extruded plastic scintillator for MINERvA

    International Nuclear Information System (INIS)

    Pla-Dalmau, Anna; Bross, Alan D.; FermilabRykalin, Victor V.; Wood, Brian M.; NICADD, DeKalb

    2005-01-01

    An extrusion line has recently been installed at Fermilab in collaboration with NICADD (Northern Illinois Center for Accelerator and Detector Development). This new facility will serve to further develop and improve extruded plastic scintillator. Since polystyrene is widely used in the consumer industry, the logical path was to investigate the extrusion of commercial-grade polystyrene pellets with dopants to yield high quality plastic scintillator. The D0 and MINOS experiments are already using extruded scintillator strips in their detectors. A new experiment at Fermilab is pursuing the use of extruded plastic scintillator. A new plastic scintillator strip is being tested and its properties characterized. The initial results are presented here

  1. Scintillators for positron emission tomography

    International Nuclear Information System (INIS)

    Moses, W.W.; Derenzo, S.E.

    1995-09-01

    Like most applications that utilize scintillators for gamma detection, Positron Emission Tomography (PET) desires materials with high light output, short decay time, and excellent stopping power that are also inexpensive, mechanically rugged, and chemically inert. Realizing that this ''ultimate'' scintillator may not exist, this paper evaluates the relative importance of these qualities and describes their impact on the imaging performance of PET. The most important PET scintillator quality is the ability to absorb 511 keV photons in a small volume, which affects the spatial resolution of the camera. The dominant factor is a short attenuation length (≤ 1.5 cm is required), although a high photoelectric fraction is also important (> 30% is desired). The next most important quality is a short decay time, which affects both the dead time and the coincidence timing resolution. Detection rates for single 511 keV photons can be extremely high, so decay times ≤ 500 ns are essential to avoid dead time losses. In addition, positron annihilations are identified by time coincidence so ≤5 ns fwhm coincidence pair timing resolution is required to identify events with narrow coincidence windows, reducing contamination due to accidental coincidences. Current trends in PET cameras are toward septaless, ''fully-3D'' cameras, which have significantly higher count rates than conventional 2-D cameras and so place higher demands on scintillator decay time. Light output affects energy resolution, and thus the ability of the camera to identify and reject events where the initial 511 keV photon has undergone Compton scatter in the patient. The scatter to true event fraction is much higher in fully-3D cameras than in 2-D cameras, so future PET cameras would benefit from scintillators with a 511 keV energy resolution < 10--12% fwhm

  2. Energy resolution of scintillation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Moszyński, M., E-mail: M.Moszynski@ncbj.gov.pl; Syntfeld-Każuch, A.; Swiderski, L.; Grodzicka, M.; Iwanowska, J.; Sibczyński, P.; Szczęśniak, T.

    2016-01-01

    According to current knowledge, the non-proportionality of the light yield of scintillators appears to be a fundamental limitation of energy resolution. A good energy resolution is of great importance for most applications of scintillation detectors. Thus, its limitations are discussed below; which arise from the non-proportional response of scintillators to gamma rays and electrons, being of crucial importance to the intrinsic energy resolution of crystals. The important influence of Landau fluctuations and the scattering of secondary electrons (δ-rays) on intrinsic resolution is pointed out here. The study on undoped NaI and CsI at liquid nitrogen temperature with a light readout by avalanche photodiodes strongly suggests that the non-proportionality of many crystals is not their intrinsic property and may be improved by selective co-doping. Finally, several observations that have been collected in the last 15 years on the influence of the slow components of light pulses on energy resolution suggest that more complex processes are taking place in the scintillators. This was observed with CsI(Tl), CsI(Na), ZnSe(Te), and undoped NaI at liquid nitrogen temperature and, finally, for NaI(Tl) at temperatures reduced below 0 °C. A common conclusion of these observations is that the highest energy resolution, and particularly intrinsic resolution measured with the scintillators, characterized by two or more components of the light pulse decay, is obtainable when the spectrometry equipment integrates the whole light of the components. In contrast, the slow components observed in many other crystals degrade the intrinsic resolution. In the limiting case, afterglow could also be considered as a very slow component that spoils the energy resolution. The aim of this work is to summarize all of the above observations by looking for their origin.

  3. High Efficiency, Low Cost Scintillators for PET

    International Nuclear Information System (INIS)

    Kanai Shah

    2007-01-01

    Inorganic scintillation detectors coupled to PMTs are an important element of medical imaging applications such as positron emission tomography (PET). Performance as well as cost of these systems is limited by the properties of the scintillation detectors available at present. The Phase I project was aimed at demonstrating the feasibility of producing high performance scintillators using a low cost fabrication approach. Samples of these scintillators were produced and their performance was evaluated. Overall, the Phase I effort was very successful. The Phase II project will be aimed at advancing the new scintillation technology for PET. Large samples of the new scintillators will be produced and their performance will be evaluated. PET modules based on the new scintillators will also be built and characterized

  4. The quest for the ideal inorganic scintillator

    International Nuclear Information System (INIS)

    Derenzo, S.E.; Weber, M.J.; Bourret-Courchesne, E.; Klintenberg, M.K.

    2002-01-01

    The past half century has witnessed the discovery of many new inorganic scintillator materials and numerous advances in our understanding of the basic physical processes governing the transformation of ionizing radiation into scintillation light. Whereas scintillators are available with a good combination of physical properties, none provides the desired combination of stopping power, light output, and decay time. A review of the numerous scintillation mechanisms of known inorganic scintillators reveals why none of them is both bright and fast. The mechanisms of radiative recombination in wide-bandgap direct semiconductors, however, remain relatively unexploited for scintillators. We describe how suitably doped semiconductor scintillators could provide a combination of high light output, short decay time, and linearity of response that approach fundamental limits

  5. Viscoelastic behavior of rubbery materials

    CERN Document Server

    Roland, C M

    2011-01-01

    The gigantic size of polymer molecules makes them viscoelastic - their behavior changes depending on how fast and for how long the material is used. This book looks at the latest discoveries in the field from a fundamental molecular perspective, in order to guide the development of better and new applications for soft materials.

  6. Why pens have rubbery grips

    Science.gov (United States)

    Dzidek, Brygida; Bochereau, Séréna; Johnson, Simon A.; Hayward, Vincent; Adams, Michael J.

    2017-10-01

    The process by which human fingers gives rise to stable contacts with smooth, hard objects is surprisingly slow. Using high-resolution imaging, we found that, when pressed against glass, the actual contact made by finger pad ridges evolved over time following a first-order kinetics relationship. This evolution was the result of a two-stage coalescence process of microscopic junctions made between the keratin of the stratum corneum of the skin and the glass surface. This process was driven by the secretion of moisture from the sweat glands, since increased hydration in stratum corneum causes it to become softer. Saturation was typically reached within 20 s of loading the contact, regardless of the initial moisture state of the finger and of the normal force applied. Hence, the gross contact area, frequently used as a benchmark quantity in grip and perceptual studies, is a poor reflection of the actual contact mechanics that take place between human fingers and smooth, impermeable surfaces. In contrast, the formation of a steady-state contact area is almost instantaneous if the counter surface is soft relative to keratin in a dry state. It is for this reason that elastomers are commonly used to coat grip surfaces.

  7. A helical scintillating fiber hodoscope

    CERN Document Server

    Altmeier, M; Bisplinghoff, J; Bissel, T; Bollmann, R; Busch, M; Büsser, K; Colberg, T; Demiroers, L; Diehl, O; Dohrmann, F; Engelhardt, H P; Eversheim, P D; Felden, O; Gebel, R; Glende, M; Greiff, J; Gross, A; Gross-Hardt, R; Hinterberger, F; Jahn, R; Jeske, M; Jonas, E; Krause, H; Lahr, U; Langkau, R; Lindemann, T; Lindlein, J; Maier, R; Maschuw, R; Mayer-Kuckuck, T; Meinerzhagen, A; Naehle, O; Pfuff, M; Prasuhn, D; Rohdjess, H; Rosendaal, D; Von Rossen, P; Sanz, B; Schirm, N; Schulz-Rojahn, M; Schwarz, V; Scobel, W; Thomas, S; Trelle, H J; Weise, E; Wellinghausen, A; Wiedmann, W; Woller, K; Ziegler, R

    1999-01-01

    A novel scintillating fiber hodoscope in helically cylindric geometry has been developed for detection of low multiplicity events of fast protons and other light charged particles in the internal target experiment EDDA at the Cooler Synchrotron COSY. The hodoscope consists of 640 scintillating fibers (2.5 mm diameter), arranged in four layers surrounding the COSY beam pipe. The fibers are helically wound in opposing directions and read out individually using 16-channel photomultipliers connected to a modified commercial encoding system. The detector covers an angular range of 9 deg. <= THETA<=72 deg. and 0 deg. <=phi (cursive,open) Greek<=360 deg. in the lab frame. The detector length is 590 mm, the inner diameter 161 mm. Geometry and granularity of the hodoscope afford a position resolution of about 1.3 mm. The detector design took into consideration a maximum of reliability and a minimum of maintenance. An LED array may be used for monitoring purposes. (author)

  8. Silicon photomultipliers for scintillating trackers

    Energy Technology Data Exchange (ETDEWEB)

    Rabaioli, S., E-mail: simone.rabaioli@gmail.com [Universita degli Studi dell' Insubria, Via Valleggio, 11 - 22100 Como (Italy); Berra, A.; Bolognini, D. [Universita degli Studi dell' Insubria, Via Valleggio, 11 - 22100 Como (Italy); INFN sezione di Milano Bicocca (Italy); Bonvicini, V. [INFN sezione di Trieste (Italy); Bosisio, L. [Universita degli Studi di Trieste and INFN sezione di Trieste (Italy); Ciano, S.; Iugovaz, D. [INFN sezione di Trieste (Italy); Lietti, D. [Universita degli Studi dell' Insubria, Via Valleggio, 11 - 22100 Como (Italy); INFN sezione di Milano Bicocca (Italy); Penzo, A. [INFN sezione di Trieste (Italy); Prest, M. [Universita degli Studi dell' Insubria, Via Valleggio, 11 - 22100 Como (Italy); INFN sezione di Milano Bicocca (Italy); Rashevskaya, I.; Reia, S. [INFN sezione di Trieste (Italy); Stoppani, L. [Universita degli Studi dell' Insubria, Via Valleggio, 11 - 22100 Como (Italy); Vallazza, E. [INFN sezione di Trieste (Italy)

    2012-12-11

    In recent years, silicon photomultipliers (SiPMs) have been proposed as a new kind of readout device for scintillating detectors in many experiments. A SiPM consists of a matrix of parallel-connected pixels, which are independent photon counters working in Geiger mode with very high gain ({approx}10{sup 6}). This contribution presents the use of an array of eight SiPMs (manufactured by FBK-irst) for the readout of a scintillating bar tracker (a small size prototype of the Electron Muon Ranger detector for the MICE experiment). The performances of the SiPMs in terms of signal to noise ratio, efficiency and time resolution will be compared to the ones of a multi-anode photomultiplier tube (MAPMT) connected to the same bars. Both the SiPMs and the MAPMT are interfaced to a VME system through a 64 channel MAROC ASIC.

  9. Silicon photomultipliers for scintillating trackers

    Science.gov (United States)

    Rabaioli, S.; Berra, A.; Bolognini, D.; Bonvicini, V.; Bosisio, L.; Ciano, S.; Iugovaz, D.; Lietti, D.; Penzo, A.; Prest, M.; Rashevskaya, I.; Reia, S.; Stoppani, L.; Vallazza, E.

    2012-12-01

    In recent years, silicon photomultipliers (SiPMs) have been proposed as a new kind of readout device for scintillating detectors in many experiments. A SiPM consists of a matrix of parallel-connected pixels, which are independent photon counters working in Geiger mode with very high gain (∼106). This contribution presents the use of an array of eight SiPMs (manufactured by FBK-irst) for the readout of a scintillating bar tracker (a small size prototype of the Electron Muon Ranger detector for the MICE experiment). The performances of the SiPMs in terms of signal to noise ratio, efficiency and time resolution will be compared to the ones of a multi-anode photomultiplier tube (MAPMT) connected to the same bars. Both the SiPMs and the MAPMT are interfaced to a VME system through a 64 channel MAROC ASIC.

  10. LHCb Upgrade: Scintillating Fibre Tracker

    International Nuclear Information System (INIS)

    Tobin, Mark

    2016-01-01

    The LHCb detector will be upgraded during the Long Shutdown 2 (LS2) of the LHC in order to cope with higher instantaneous luminosities and to read out the data at 40 MHz using a trigger-less read-out system. All front-end electronics will be replaced and several sub-detectors must be redesigned to cope with higher occupancy. The current tracking detectors downstream of the LHCb dipole magnet will be replaced by the Scintillating Fibre (SciFi) Tracker. The SciFi Tracker will use scintillating fibres read out by Silicon Photomultipliers (SiPMs). State-of-the-art multi-channel SiPM arrays are being developed to read out the fibres and a custom ASIC will be used to digitise the signals from the SiPMs. The evolution of the design since the Technical Design Report in 2014 and the latest R & D results are presented.

  11. Studies of novel plastic scintillators

    International Nuclear Information System (INIS)

    McInally, I.D.

    1979-08-01

    The general aim of this study was to synthesize fluorescent compounds which are capable of polymerisation, to prepare polymers and co-polymers from these compounds and to study the photophysical properties of these materials. In this way it is hoped to produce plastic scintillators exhibiting improved energy transfer efficiency. Materials studied included POS(2-phenyl-5-(p vinyl) phenyloxazole) vinyl naphthalene, methyl anthracene terminated poly vinyl toluene) and derivatives of BuPBD. (author)

  12. Charged particle scintillation mass spectrometer

    International Nuclear Information System (INIS)

    Baranov, P.S.; Zhuravlev, E.E.; Nafikov, A.A.; Osadchi , A.I.; Raevskij, V.G.; Smirnov, P.A.; Cherepnya, S.N.; Yanulis, Yu.P.

    1982-01-01

    A scintillation mass-spectrometer for charged particle identification by the measured values of time-of-flight and energy operating on line with the D-116 computer is described. Original time detectors with 100x100x2 mm 3 and 200x2 mm 2 scintillators located on the 1- or 2 m path length are used in the spectrometer. The 200x200x200 mm 3 scintillation unit is used as a E-counter. Time-of-flight spectra of the detected particles on the 2 m path length obtained in spectrometer test in the beam of charged particles escaping from the carbon target at the angle of 130 deg under 1.2 GeV bremsstrahlung beam of the ''Pakhra'' PIAS synchrotron are presented. Proton and deuteron energy spectra as well as mass spectrum of all the particles detected by the spectrometer are given. Mass resolution obtained on the 2 m path length for π-mesons is +-25%, for protons is +-5%, for deuterons is +-3%

  13. Liquid scintillation alpha spectrometry techniques

    International Nuclear Information System (INIS)

    McKlveen, J.W.; McDowell, W.J.

    1984-01-01

    Accurate, quantitative determinations of alpha emitting nuclides by conventional plate counting methods are difficult, because of sample self-absorption problems in counting and because of non-reproducible losses in conventional sample separation methods. Liquid scintillation alpha spectrometry offers an attractive alternative with no sample self-absorption or geometry problems and with 100% counting efficiency. Sample preparation may include extraction of the alpha emitter of interest by a specific organic phase-soluble compound directly into the liquid scintillation counting medium. Detection electronics use energy and pulse-shape discrimination, to yield alpha spectra without beta and gamma background interference. Specific procedures have been developed for gross alpha, uranium, plutonium, thorium and colonium assay. Possibilities for a large number of other applications exist. Accuracy and reproducibility are typically in the 1% range. Backgrounds of the order of 0.01 cpm are readily achievable. The paper will present an overview of liquid scintillation alpha counting techniques and some of the results achieved for specific applications. (orig.)

  14. Ionospheric scintillation monitoring and modelling

    Directory of Open Access Journals (Sweden)

    Mariusz Pozoga

    2009-06-01

    Full Text Available

    This paper presents a review of the ionospheric scintillation monitoring and modelling by the European groups

    involved in COST 296. Several of these groups have organized scintillation measurement campaigns at low and

    high latitudes. Some characteristic results obtained from the measured data are presented. The paper also addresses the modeling activities: four models, based on phase screen techniques, with different options and application domains are detailed. Finally some new trends for research topics are given. This includes the wavelet analysis, the high latitudes analysis, the construction of scintillation maps and the mitigation techniques.


  15. Multi element high resolution scintillator structure

    International Nuclear Information System (INIS)

    Cusano, D.A.

    1980-01-01

    A gamma camera scintillator structure, suitable for detecting high energy gamma photons which, in a single scintillator camera, would require a comparatively thick scintillator crystal, so resulting in unacceptable dispersion of light photons, comprises a collimator array of a high Z material with elongated, parallel wall channels with the scintillator material being disposed in one end of the channels so as to form an integrated collimator/scintillator structure. The collimator channel walls are preferably coated with light reflective material and further light reflective surfaces being translucent to gamma photons, may be provided in each channel. The scintillators may be single crystals or preferably comprise a phosphor dispersed in a thermosetting translucent matrix as disclosed in GB2012800A. The light detectors of the assembled camera may be photomultiplier tubes charge coupled devices or charge injection devices. (author)

  16. 4 GHz ionospheric scintillations observed at Taipei

    International Nuclear Information System (INIS)

    Huang, Y.N.; Jeng, B.S.

    1978-01-01

    In a study of ionospheric scintillations 3950 MHz beacon signals from geostationary communication satellites Intelsat-IV-F8 and Intelsat-IV-F1 were recorded on a strip chart and magnetic tape at the Taipei Earth Station. While the strip charts were used to monitor the occurrence of the scintillation, the magnetic tape output was digitized and processed by a computerized system to yield a detailed analysis of scintillation events. It was found that diurnal variations were similar to the diurnal patterns of sporadic E at greater than 5 MHz and VHF band ionospheric scintillations during daytime as reported by Huang (1978). Eight typical scintillation events were selected for the calculation of the scintillation index, S4, and other parameters. The mean S4 index for the 8 events was found to be 0.15. Numerical and graphic results are presented for the cumulative amplitude distributions, message reliability, autocorrelation functions and power spectra

  17. A Review of Ionospheric Scintillation Models.

    Science.gov (United States)

    Priyadarshi, S

    This is a general review of the existing climatological models of ionospheric radio scintillation for high and equatorial latitudes. Trans-ionospheric communication of radio waves from transmitter to user is affected by the ionosphere which is highly variable and dynamic in both time and space. Scintillation is the term given to irregular amplitude and phase fluctuations of the received signals and related to the electron density irregularities in the ionosphere. Key sources of ionospheric irregularities are plasma instabilities; every irregularities model is based on the theory of radio wave propagation in random media. It is important to understand scintillation phenomena and the approach of different theories. Therefore, we have briefly discussed the theories that are used to interpret ionospheric scintillation data. The global morphology of ionospheric scintillation is also discussed briefly. The most important (in our opinion) analytical and physical models of scintillation are reviewed here.

  18. Morphology of auroral zone radio wave scintillation

    International Nuclear Information System (INIS)

    Rino, C.L.; Matthews, S.J.

    1980-01-01

    This paper describes the morphology of midnight sector and morning sector auroral zone scintillation observations made over a two-year period using the Wideband satelite, which is in a sun-synchronous, low-altitude orbit. No definitive seasonal variation was found. The nighttime data showed the highest scintillation ocurrence levels, but significant amounts of morning scintillation were observed. For the most part the scintillation activity followed the general pattern of local magnetic activity. The most prominent feature in the nightime data is a localized amplitude and phase scintillation enhancement at the point where the propagation vector lies within an L shell. A geometrical effect due to a dynamic slab of sheetlike structures in the F region is hypothesized as the source of his enhancement. The data have been sorted by magnetic activity, proximity to local midnight, and season. The general features of the data are in agreement with the accepted morphology of auroral zone scintillation

  19. Semitransparent ZnO/poly(3,4-ethylenedioxythiophene) based hybrid inorganic/organic heterojunction thin film diodes prepared by combined radio-frequency magnetron-sputtering and electrodeposition techniques

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Moreno, Jorge; Navarrete-Astorga, Elena; Martin, Francisco [Laboratorio de Materiales y Superficies (Unidad Asociada al CSIC), Departamentos de Fisica Aplicada and Ing. Quimica, Universidad de Malaga, E29071 Malaga (Spain); Schrebler, Ricardo [Instituto de Quimica, Facultad de Ciencias, Pontificia Universidad Catolica de Valparaiso, Casilla 4059, Valparaiso (Chile); Ramos-Barrado, Jose R. [Laboratorio de Materiales y Superficies (Unidad Asociada al CSIC), Departamentos de Fisica Aplicada and Ing. Quimica, Universidad de Malaga, E29071 Malaga (Spain); Dalchiele, Enrique A., E-mail: dalchiel@fing.edu.uy [Instituto de Fisica, Facultad de Ingenieria, Herrera y Reissig 565, C.C. 30, 11000 Montevideo (Uruguay)

    2012-12-15

    n-ZnO/p-poly(3,4-ethylenedioxythiophene) (PEDOT) semitransparent inorganic-organic hybrid vertical heterojunction thin film diodes have been fabricated with PEDOT and ZnO thin films grown by electrodeposition and radio-frequency magnetron-sputtering respectively, onto a tin doped indium oxide coated glass substrate. The diode exhibited an optical transmission of {approx} 40% to {approx} 50% in the visible region between 450 and 700 nm. The current-voltage (I-V) characteristics of the heterojunction show good rectifying diode characteristics, with a ratio of forward current to the reverse current as high as 35 in the range - 4 V to + 4 V. The I-V characteristic was examined in the framework of the thermionic emission model. The ideality factor and barrier height were obtained as 4.0 and 0.88 eV respectively. - Highlights: Black-Right-Pointing-Pointer Semitransparent inorganic-organic heterojunction thin film diodes investigated Black-Right-Pointing-Pointer n-ZnO/p-poly(3,4-ethylenedioxythipohene) used for the heterojunction Black-Right-Pointing-Pointer Diodes exhibited an optical transmission of {approx} 40%-{approx} 50% in the visible region Black-Right-Pointing-Pointer Heterojunction current-voltage features show good rectifying diode characteristics Black-Right-Pointing-Pointer A forward to reverse current ratio as high as 35 (- 4 V to + 4 V range) was attained.

  20. Scintillation properties of quantum-dot doped styrene based plastic scintillators

    International Nuclear Information System (INIS)

    Park, J.M.; Kim, H.J.; Hwang, Y.S.; Kim, D.H.; Park, H.W.

    2014-01-01

    We fabricated quantum-dot doped plastic scintillators in order to control the emission wavelength. We studied the characterization of the quantum-dots (CdSe/ZnS) and PPO (2, 5-diphenyloxazole) doped styrene based plastic scintillators. PPO is usually used as a dopant to enhance the scintillation properties of organic scintillators with a maximum emission wavelength of 380 nm. In order to study the scintillation properties of the quantum-dots doped plastic scintillators, the samples were irradiated with X-ray, photon, and 45 MeV proton beams. We observed that only PPO doped plastic scintillators shows a luminescence peak around 380 nm. However, both the quantum-dots and PPO doped plastic scintillators shows luminescence peaks around 380 nm and 520 nm. Addition of quantum-dots had shifted the luminescence spectrum from 380 nm (PPO) toward the region of 520 nm (Quantum-dots). Emissions with wavelength controllable plastic scintillators can be matched to various kinds of photosensors such as photomultiplier tubes, photo-diodes, avalanche photo-diodes, and CCDs, etc. Also quantum-dots doped plastic scintillator, which is irradiated 45 MeV proton beams, shows that the light yield of quantum-dots doped plastic scintillator is increases as quantum-dots doping concentration increases at 520 nm. And also the plastic scintillators were irradiated with Cs-137 γ-ray for measuring fluorescence decay time. -- Highlights: • Quantum-dot doped plastic scintillator is grown by the thermal polymerization method. • Quantum-dot doped plastic scintillators can control the emission wavelength to match with photo-sensor. • Quantum-dots and PPO doped plastic scintillators emitted luminescence peaks around 380 nm and 520 nm. • We observed the energy transfer from PPO to quantum-dot in the quantum-dot doped plastic scintillator

  1. Scintillation properties of quantum-dot doped styrene based plastic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Park, J.M.; Kim, H.J., E-mail: hongjooknu@gmail.com; Hwang, Y.S.; Kim, D.H.; Park, H.W.

    2014-02-15

    We fabricated quantum-dot doped plastic scintillators in order to control the emission wavelength. We studied the characterization of the quantum-dots (CdSe/ZnS) and PPO (2, 5-diphenyloxazole) doped styrene based plastic scintillators. PPO is usually used as a dopant to enhance the scintillation properties of organic scintillators with a maximum emission wavelength of 380 nm. In order to study the scintillation properties of the quantum-dots doped plastic scintillators, the samples were irradiated with X-ray, photon, and 45 MeV proton beams. We observed that only PPO doped plastic scintillators shows a luminescence peak around 380 nm. However, both the quantum-dots and PPO doped plastic scintillators shows luminescence peaks around 380 nm and 520 nm. Addition of quantum-dots had shifted the luminescence spectrum from 380 nm (PPO) toward the region of 520 nm (Quantum-dots). Emissions with wavelength controllable plastic scintillators can be matched to various kinds of photosensors such as photomultiplier tubes, photo-diodes, avalanche photo-diodes, and CCDs, etc. Also quantum-dots doped plastic scintillator, which is irradiated 45 MeV proton beams, shows that the light yield of quantum-dots doped plastic scintillator is increases as quantum-dots doping concentration increases at 520 nm. And also the plastic scintillators were irradiated with Cs-137 γ-ray for measuring fluorescence decay time. -- Highlights: • Quantum-dot doped plastic scintillator is grown by the thermal polymerization method. • Quantum-dot doped plastic scintillators can control the emission wavelength to match with photo-sensor. • Quantum-dots and PPO doped plastic scintillators emitted luminescence peaks around 380 nm and 520 nm. • We observed the energy transfer from PPO to quantum-dot in the quantum-dot doped plastic scintillator.

  2. Measurements of energy resolution with hemispheric scintillators

    International Nuclear Information System (INIS)

    Mendonca, A.C.S.; Binns, D.A.C.; Tauhata, L.; Poledna, R.

    1980-01-01

    The hemispheric configuration is used for plastic scintillators type NE 102 with the aiming to optimize the light collect. Scintillators at this configuration, with radii of 3,81 cm and 2,54 cm, are showing improvement about 16-17% in the energy resolution, on cilyndric scintillators with the same volume, for gamma rays of 511-1275 KeV. (E.G.) [pt

  3. Random wave fields and scintillated beams

    CSIR Research Space (South Africa)

    Roux, FS

    2009-01-01

    Full Text Available F. Stef Roux CSIR National Laser Centre PO Box 395, Pretoria 0001, South Africa CSIR National Laser Centre – p.1/29 Contents . Scintillated beams and adaptive optics . Detecting a vortex — Shack-Hartmann . Remove optical vortices . Random vortex... beam. CSIR National Laser Centre – p.3/29 Weak scintillation If the scintillation is weak the resulting phase function of the optical beam is still continuous. Such a weakly scintillated beam can be corrected by an adaptive optical system. CSIR National...

  4. High-symmetry organic scintillator systems

    Energy Technology Data Exchange (ETDEWEB)

    Feng, Patrick L.

    2018-03-13

    An ionizing radiation detector or scintillator system includes a scintillating material comprising an organic crystalline compound selected to generate photons in response to the passage of ionizing radiation. The organic compound has a crystalline symmetry of higher order than monoclinic, for example an orthorhombic, trigonal, tetragonal, hexagonal, or cubic symmetry. A photodetector is optically coupled to the scintillating material, and configured to generate electronic signals having pulse shapes based on the photons generated in the scintillating material. A discriminator is coupled to the photon detector, and configured to discriminate between neutrons and gamma rays in the ionizing radiation based on the pulse shapes of the output signals.

  5. Designing an optimally proportional inorganic scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Jai, E-mail: jai.singh@cdu.edu.au [School of Engineering and IT, B-Purple-12, Faculty of EHSE, Charles Darwin University, NT 0909 (Australia); Koblov, Alexander [School of Engineering and IT, B-Purple-12, Faculty of EHSE, Charles Darwin University, NT 0909 (Australia)

    2012-09-01

    The nonproportionality observed in the light yield of inorganic scintillators is studied theoretically as a function of the rates of bimolecular and Auger quenching processes occurring within the electron track initiated by a gamma- or X-ray photon incident on a scintillator. Assuming a cylindrical track, the influence of the track radius and concentration of excitations created within the track on the scintillator light yield is also studied. Analysing the calculated light yield a guideline for inventing an optimally proportional scintillator with optimal energy resolution is presented.

  6. Designing an optimally proportional inorganic scintillator

    International Nuclear Information System (INIS)

    Singh, Jai; Koblov, Alexander

    2012-01-01

    The nonproportionality observed in the light yield of inorganic scintillators is studied theoretically as a function of the rates of bimolecular and Auger quenching processes occurring within the electron track initiated by a gamma- or X-ray photon incident on a scintillator. Assuming a cylindrical track, the influence of the track radius and concentration of excitations created within the track on the scintillator light yield is also studied. Analysing the calculated light yield a guideline for inventing an optimally proportional scintillator with optimal energy resolution is presented.

  7. High-symmetry organic scintillator systems

    Science.gov (United States)

    Feng, Patrick L.

    2017-07-18

    An ionizing radiation detector or scintillator system includes a scintillating material comprising an organic crystalline compound selected to generate photons in response to the passage of ionizing radiation. The organic compound has a crystalline symmetry of higher order than monoclinic, for example an orthorhombic, trigonal, tetragonal, hexagonal, or cubic symmetry. A photodetector is optically coupled to the scintillating material, and configured to generate electronic signals having pulse shapes based on the photons generated in the scintillating material. A discriminator is coupled to the photon detector, and configured to discriminate between neutrons and gamma rays in the ionizing radiation based on the pulse shapes of the output signals.

  8. Some adsorption characteristics of polysterene base scintillators

    International Nuclear Information System (INIS)

    Seredenko, T.N.; Ehkkerman, V.M.; Solomonov, V.M.; Gen, N.S.

    1980-01-01

    It is necessary to account for the adsorption on the surface of a scintillator when measuring nuclide activity in solutions by submerging into these solutions plastic scintillators. Dependences of 144 Ce, 90 Y, 137 Cs adsorption on specific activities (α) and pH value of solution were investigated. It is shown that K-α ratio is described by the equation K=Casup(p), where K is the specific surface activity of the polystyrene scintillator. Values of C and p are presented for investigated nuclides. The criterion estimating the possibility for repeated usage of scintillator are considered

  9. Design of Fluorescent Compounds for Scintillation Detection

    Energy Technology Data Exchange (ETDEWEB)

    Pla-Dalmau, Anna [Northern Illinois U.

    1990-01-01

    Plastic scintillation detectors for high energy physics applications require the development of new fluorescent compounds to meet the demands set by the future generation of particle accelerators such as the Superconducting Supercollider (SSe). Plastic scintillators are commonly based on a polymer matrix doped with two fluorescent compounds: the primary dopant and the wavelength shifter. Their main characteristics are fast response time and high quantum efficiency. The exposure to larger radiation doses and demands for larger light output questions their survivability in the future experiments. A new type of plastic scintillator - intrinsic scintillator - has been suggested. It uses a single dopant as primary and wavelength shifter, and should be less susceptible to radiation damage....

  10. Waveshifters and Scintillators for Ionizing Radiation Detection

    International Nuclear Information System (INIS)

    Baumgaugh, B.; Bishop, J.; Karmgard, D.; Marchant, J.; McKenna, M.; Ruchti, R.; Vigneault, M.; Hernandez, L.; Hurlbut, C.

    2007-01-01

    Scintillation and waveshifter materials have been developed for the detection of ionizing radiation in an STTR program between Ludlum Measurements, Inc. and the University of Notre Dame. Several new waveshifter materials have been developed which are comparable in efficiency and faster in fluorescence decay than the standard material Y11 (K27) used in particle physics for several decades. Additionally, new scintillation materials useful for fiber tracking have been developed which have been compared to 3HF. Lastly, work was done on developing liquid scintillators and paint-on scintillators and waveshifters for high radiation environments

  11. High-symmetry organic scintillator systems

    Science.gov (United States)

    Feng, Patrick L.

    2018-02-06

    An ionizing radiation detector or scintillator system includes a scintillating material comprising an organic crystalline compound selected to generate photons in response to the passage of ionizing radiation. The organic compound has a crystalline symmetry of higher order than monoclinic, for example an orthorhombic, trigonal, tetragonal, hexagonal, or cubic symmetry. A photodetector is optically coupled to the scintillating material, and configured to generate electronic signals having pulse shapes based on the photons generated in the scintillating material. A discriminator is coupled to the photon detector, and configured to discriminate between neutrons and gamma rays in the ionizing radiation based on the pulse shapes of the output signals.

  12. Collimator changer for scintillation camera

    International Nuclear Information System (INIS)

    Jupa, E.C.; Meeder, R.L.; Richter, E.K.

    1976-01-01

    A collimator changing assembly mounted on the support structure of a scintillation camera is described. A vertical support column positioned proximate the detector support column with a plurality of support arms mounted thereon in a rotatable cantilevered manner at separate vertical positions. Each support arm is adapted to carry one of the plurality of collimators which are interchangeably mountable on the underside of the detector and to transport the collimator between a store position remote from the detector and a change position underneath said detector

  13. New shaper of scintillation signals

    International Nuclear Information System (INIS)

    Brovchenko, V.G.

    2001-01-01

    Summation of the exponential shape pulse (abrupt front, exponential fall-off) with the pulse, proportional to its integral (the integration time constant is equal to the exponent fall-off constant), results in the pulse, the apex whereof is horizontal (parallel to the base line). Such a pulse is suitable for registration through standard analog-to-digital converters of the consecutive binary approximation, The described scheme is accomplished for verification of the basic principle of the shaper action. The parameters of the scheme are approximated to those ones, necessary for processing scintillation signals NaI(Tl) [ru

  14. Scintillating fibre tracking neutron detector

    International Nuclear Information System (INIS)

    Karlsson, Joakim.

    1995-04-01

    A detector for measurements of collimated fluxes of neutrons in the energy range 2-20 MeV is proposed. It utilizes (n.p) elastic scattering in scintillating optical fibres placed in successive orthogonal layers perpendicular to the neutron flux. A test module has been designed, constructed and tested with respect to separation of neutron and gamma events. The pulse height measurements show the feasibility to discriminate between neutron, gamma and background events. Application to measurements of fusion neutrons is considered. 18 refs, 22 figs, 4 tabs

  15. Pulsar scintillation patterns and strangelets

    Energy Technology Data Exchange (ETDEWEB)

    Pérez-García, M. Ángeles, E-mail: mperezga@usal.es [Department of Fundamental Physics and IUFFyM, University of Salamanca, Plaza de la Merced s/n, 37008 Salamanca (Spain); Silk, Joseph, E-mail: silk@iap.fr [Institut d' Astrophysique, UMR 7095, CNRS, Université Pierre et Marie Curie, 98bis Blvd Arago, 75014 Paris (France); Department of Physics and Astronomy, Johns Hopkins University, Homewood Campus, Baltimore MD 21218 (United States); Beecroft Institute of Particle Astrophysics and Cosmology, Department of Physics, University of Oxford, Oxford OX1 3RH (United Kingdom); Pen, Ue-Li, E-mail: pen@cita.utoronto.ca [Canadian Institute for Theoretical Astrophysics, University of Toronto, 0N M5S 3H8 (Canada)

    2013-12-18

    We propose that interstellar extreme scattering events, usually observed as pulsar scintillations, may be caused by a coherent agent rather than the usually assumed turbulence of H{sub 2} clouds. We find that the penetration of a flux of ionizing, positively charged strangelets or quark nuggets into a dense interstellar hydrogen cloud may produce ionization trails. Depending on the specific nature and energy of the incoming droplets, diffusive propagation or even capture in the cloud are possible. As a result, enhanced electron densities may form and constitute a lens-like scattering screen for radio pulsars and possibly for quasars.

  16. Mounting LHCb hadron calorimeter scintillating tiles

    CERN Multimedia

    Maximilien Brice

    2004-01-01

    Scintillating tiles are carefully mounted in the hadronic calorimeter for the LHCb detector. These calorimeters measure the energy of particles that interact via the strong force, called hadrons. The detectors are made in a sandwich-like structure where these scintillator tiles are placed between metal sheets.

  17. Lower bounds on scintillation detector timing performance

    International Nuclear Information System (INIS)

    Clinthorne, N.H.; Rogers, W.L.; Hero, A.O. III.; Petrick, N.A.

    1990-01-01

    Fundamental method-independent limits on the timing performance of scintillation detectors are useful for identifying regimes in which either present timing methods are nearly optimal or where a considerable performance gain might be realized using better pulse processing techniques. Several types of lower bounds on mean-squared timing error (MSE) performance have been developed and applied to scintillation detectors. The simple Cramer-Rao (CR) bound can be useful in determining the limiting MSE for scintillators having a relatively high rate of photon problction such as BaF 2 and NaI(Tl); however, it tends to overestimate the achievalbe performance for scintillators with lower rates such as BGO. For this reason, alternative bounds have been developed using rate-distortion theory or by assuming that the conversion of energy to scintillation light must pass through excited states which have exponential lifetime densities. The bounds are functions of the mean scintillation pulse shape, the scintillation intensity, and photodetector characteristics; they are simple to evaluate and can be used to conveniently assess the limiting timing performance of scintillation detectors. (orig.)

  18. Scintillation device of X-ray detection

    International Nuclear Information System (INIS)

    Polack, F.; Bigler, E.

    1985-01-01

    The detection device comprises a screen made of microtubes transparent to the light emitted by a scintillator material in the microtube channels. The scintillator material optical index is greater than the microtube material index, so as to constitute optical fiber, with index rise, guiding the light toward the outside [fr

  19. Status of timing with plastic scintillation detectors

    International Nuclear Information System (INIS)

    Moszynski, M.; Bengtson, B.

    1979-01-01

    Timing properties of scintillators and photomultipliers as well as theoretical and experimental studies of time resolution of scintillation counters are reviewed. Predictions of the theory of the scintillation pulse generation processes are compared with the data on the light pulse shape from small samples, in which the light pulse shape depends only on the composition of the scintillator. For larger samples the influence of the light collection process and the self-absorption process on the light pulse shape are discussed. The data on rise times, fwhm's, decay times and light yield of several commercial scintillators used in timing are collected. The next part of the paper deals with the properties of photomultipliers. The sources of time uncertainties in photomultipliers as a spread of the initial velocity of photoelectrons, emission of photoelectrons under different angles and from different points at the photocathode, the time spread and the gain dispersion introduced by electron photomultiplier are reviewed. The experimental data on the time jitter, single electron response and photoelectron yield of some fast photomultipliers are collected. As the time resolution of the timing systems with scintillation counters depends also on time pick-off units, a short presentation of the timing methods is given. The discussion of timing theories is followed by a review of experimental studies of the time resolution of scintillation counters. The paper is ended by an analysis of prospects on further progress of the subnanosecond timing with scintillation counters. (Auth.)

  20. Current status of liquid scintillation counting

    International Nuclear Information System (INIS)

    Klingler, G.W.

    1981-01-01

    Scintillation counting of alpha particles has been used since the turn of the century. The advent of pulse shape discrimination has made this method of detection accurate and reliable. The history, concepts and development of scintillation counting and pulse shape discrimination are discussed. A brief look at the ongoing work in the consolidation of components now used for pulse shape discrimination is included

  1. Some possible improvements in scintillation calorimeters

    International Nuclear Information System (INIS)

    Lorenz, E.

    1985-03-01

    Two ideas for improvements of scintillation calorimeters will be presented: a) improved readout of scintillating, totally active electromagnetic calorimeters with combinations of silicon photodiodes and fluorescent panel collectors, b) use of time structure analysis on calorimetry, both for higher rate applications and improved resolution for hadron calorimeters. (orig.)

  2. Performance and characteristics of a new scintillator

    CERN Document Server

    Czirr, J B; MacGillivray, R R; Seddon, P J

    1999-01-01

    A new class of scintillators for neutron imaging, based upon lithium gadolinium borate, is described. These scintillators offer the ability to tailor their response to the neutron spectrum by varying the relative absorption of neutrons by the key constituents (lithium, gadolinium and boron). The isotopic compositions of each constituent can be varied in order to change the spectral response.

  3. Development of scintillation materials for PET scanners

    CERN Document Server

    Korzhik, Mikhail; Annenkov, Alexander N; Borissevitch, Andrei; Dossovitski, Alexei; Missevitch, Oleg; Lecoq, Paul

    2007-01-01

    The growing demand on PET methodology for a variety of applications ranging from clinical use to fundamental studies triggers research and development of PET scanners providing better spatial resolution and sensitivity. These efforts are primarily focused on the development of advanced PET detector solutions and on the developments of new scintillation materials as well. However Lu containing scintillation materials introduced in the last century such as LSO, LYSO, LuAP, LuYAP crystals still remain the best PET species in spite of the recent developments of bright, fast but relatively low density lanthanum bromide scintillators. At the same time Lu based materials have several drawbacks which are high temperature of crystallization and relatively high cost compared to alkali-halide scintillation materials. Here we describe recent results in the development of new scintillation materials for PET application.

  4. Detector construction for a scintillation camera

    International Nuclear Information System (INIS)

    Ashe, J.B.

    1977-01-01

    An improved transducer construction for a scintillation camera in which a light conducting element is equipped with a layer of moisture impervious material is described. A scintillation crystal is thereafter positioned in optical communication with the moisture impervious layer and the remaining surfaces of the scintillation crystal are encompassed by a moisture shield. Affixing the moisture impervious layer to the light conducting element prior to attachment of the scintillation crystal reduces the requirement for mechanical strength in the moisture impervious layer and thereby allows a layer of reduced thickness to be utilized. Preferably, photodetectors are also positioned in optical communication with the light conducting element prior to positioning the scintillation crystal in contact with the impervious layer. 13 claims, 4 figures

  5. Liquid mixtures for scintillation counters

    International Nuclear Information System (INIS)

    Kauffmann, J.M.

    1975-01-01

    Liquid scintillators contain emulsifiers or combinations of these which can be used over a wide temperature range for a multitude of aqueous samples. These emulsifiers are block-polymerides with a nonhygroscopic center part of the chain of oxypropylene combinations recieved by addition of propylene oxide to both hydroxyl groups of a propylene-glycol nucleus and both ends of the center part of the chain terminating in hygroscopic poly(oxyethylene) groups. The length of the nonhygroscopic center part of the chain varies from about 800 to 3,000 or 4,000 in molecular weight. The hygroscopic poly(oxyethylene) end groups have a controlled length constituting about 10 to 80wt.% of the finished molecule. The most useful members of this group of co-polymerides possess a length of their poly(oxypropylene) chains corresponding to a value of y of about 15 to 56 and a length of their poly(oxyethylene)chains corresponding to values of x and z between 1 and 35 . All known fluorines can be used. With the scintillators the radioimmunoassay can also be carried through. (DG/PB) [de

  6. Liquid scintillator mixable with water

    International Nuclear Information System (INIS)

    Benson, R.H.

    1976-01-01

    A liquid scintillator mixable with water is described consisting of an aromatic solvent (xylene), a scintillation material and an ethoxylated alkyl phenol (as surface-active substance). So far such kinds of system have not given good measurements on counting samples with high water content. Due to the invention's composition one gets good results even with counting samples having a water content of over 30% if the alkyl substituent of the alkyl phenol contains 7, 10, 11, 13, 14, 15 or 16 C atoms and the ratio n/x of the number n of C atoms of the alkyl substituents to the average number x of the ethoxy groups of the ethoxylated alkyl phenols lie between 0.83 and 1.67. The following alkyl phenols are mentioned: heptyl phenol (n/x between 0.83 and 1.08), decyl phenol (n/x between 0.90 and 1.17), hendecyl phenol (n/x between 0.93 and 1.22), tridecyl phenol (n/x between 0.97 and 1.34), tetradecyl phenol (n/x between 1.08 and 1.55), pentadecyl phenol (n/x between 1.15 and 1.67), hexadecyl phenol (n/x between 1.33 and 1.51). (UWI) [de

  7. Estimation of Fano factor in inorganic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Bora, Vaibhav, E-mail: bora.vaibhav@gmail.com [Center for Gamma-Ray Imaging, Department of Medical Imaging, University of Arizona and College of Optical Sciences, University of Arizona, Tucson, AZ 85724 (United States); Barrett, Harrison H., E-mail: barrett@radiology.arizona.edu [Center for Gamma-Ray Imaging, Department of Medical Imaging, University of Arizona and College of Optical Sciences, University of Arizona, Tucson, AZ 85724 (United States); Fastje, David, E-mail: dfastje@gmail.com [Center for Gamma-Ray Imaging, Department of Medical Imaging, University of Arizona and College of Optical Sciences, University of Arizona, Tucson, AZ 85724 (United States); Clarkson, Eric, E-mail: clarkson@radiology.arizona.edu [Center for Gamma-Ray Imaging, Department of Medical Imaging, University of Arizona and College of Optical Sciences, University of Arizona, Tucson, AZ 85724 (United States); Furenlid, Lars, E-mail: furen@radiology.arizona.edu [Center for Gamma-Ray Imaging, Department of Medical Imaging, University of Arizona and College of Optical Sciences, University of Arizona, Tucson, AZ 85724 (United States); Bousselham, Abdelkader, E-mail: abousselham@qf.org.qa [Qatar Foundation, QEERI, P.O. Box 5825, Doha (Qatar); Shah, Kanai S., E-mail: kanaishah@yahoo.com [Radiation Monitoring Devices, Inc., Watertown, MA 02472 (United States); Glodo, Jarek, E-mail: jglodo@rmdinc.com [Radiation Monitoring Devices, Inc., Watertown, MA 02472 (United States)

    2016-01-01

    The Fano factor of an integer-valued random variable is defined as the ratio of its variance to its mean. Correlation between the outputs of two photomultiplier tubes on opposite faces of a scintillation crystal was used to estimate the Fano factor of photoelectrons and scintillation photons. Correlations between the integrals of the detector outputs were used to estimate the photoelectron and photon Fano factor for YAP:Ce, SrI{sub 2}:Eu and CsI:Na scintillator crystals. At 662 keV, SrI{sub 2}:Eu was found to be sub-Poisson, while CsI:Na and YAP:Ce were found to be super-Poisson. An experiment setup inspired from the Hanbury Brown and Twiss experiment was used to measure the correlations as a function of time between the outputs of two photomultiplier tubes looking at the same scintillation event. A model of the scintillation and the detection processes was used to generate simulated detector outputs as a function of time for different values of Fano factor. The simulated outputs from the model for different Fano factors was compared to the experimentally measured detector outputs to estimate the Fano factor of the scintillation photons for YAP:Ce, LaBr{sub 3}:Ce scintillator crystals. At 662 keV, LaBr{sub 3}:Ce was found to be sub-Poisson, while YAP:Ce was found to be close to Poisson.

  8. Geophysical analysis of coherent satellite scintillation data

    Science.gov (United States)

    Fremouw, E. J.; Lansinger, J. M.; Miller, D. A.

    1981-11-01

    In May of 1976, Air Force Satellite P76-5 was launched with the Defense Nuclear Agency's Wideband beacon, DNA-002, as its sole payload. Several researchers have employed the resulting data in studies of ionospheric structure and its effect on transionospheric radio communications. In the present work, recordings of amplitude and phase scintillation imposed on Wideband's VHF and UHF signals by the ionosphere have been used to study medium-scale structures in the auroral-zone F layer. Results include quantitative identification of a very close relationship between scintillation and solar/geomagnetic activity, together with lack of a seasonal variation in scintillation activity in the Alaskan sector. A surprisingly high correlation (90%) was found between monthly means of phase-scintillation index, on the one hand, and sunspot number and 10-cm solar radio flux, on the other. The high-latitude scintillation boundary was found to be very similar to the soft-electron precipitation boundary, including similarity in expansion rates with increasing magnetic activity. Interestingly, it is systematically shifted poleward of the precipitation boundary on the day side of the earth and equatorward on the night side. Taken together, the results of this research disclose a rather direct relationship between scintillation and soft-electron precipitation, with plasma convection likely playing an important role in generation of the scintillation-producing irregularities.

  9. Liquid scintillation counting system with automatic gain correction

    International Nuclear Information System (INIS)

    Frank, R.B.

    1976-01-01

    An automatic liquid scintillation counting apparatus is described including a scintillating medium in the elevator ram of the sample changing apparatus. An appropriate source of radiation, which may be the external source for standardizing samples, produces reference scintillations in the scintillating medium which may be used for correction of the gain of the counting system

  10. Scintillation counter: photomultiplier tube alignment

    International Nuclear Information System (INIS)

    Olson, R.E.

    1975-01-01

    A scintillation counter, particularly for counting gamma ray photons, includes a massive lead radiation shield surrounding a sample-receiving zone. The shield is disassembleable into a plurality of segments to allow facile installation and removal of a photomultiplier tube assembly, the segments being so constructed as to prevent straight-line access of external radiation through the shield into the sample receiving zone. Provisions are made for accurately aligning the photomultiplier tube with respect to one or more sample-transmitting bores extending through the shield to the sample receiving zone. A sample elevator, used in transporting samples into the zone, is designed to provide a maximum gamma-receiving aspect to maximize the gamma detecting efficiency. (auth)

  11. Scintillation counter, maximum gamma aspect

    International Nuclear Information System (INIS)

    Thumim, A.D.

    1975-01-01

    A scintillation counter, particularly for counting gamma ray photons, includes a massive lead radiation shield surrounding a sample-receiving zone. The shield is disassembleable into a plurality of segments to allow facile installation and removal of a photomultiplier tube assembly, the segments being so constructed as to prevent straight-line access of external radiation through the shield into radiation-responsive areas. Provisions are made for accurately aligning the photomultiplier tube with respect to one or more sample-transmitting bores extending through the shield to the sample receiving zone. A sample elevator, used in transporting samples into the zone, is designed to provide a maximum gamma-receiving aspect to maximize the gamma detecting efficiency. (U.S.)

  12. A new plastic scintillator with large Stokes shift

    International Nuclear Information System (INIS)

    Destruel, P.; Taufer, M.

    1989-01-01

    We have developed a new plastic scintillator with the novel characteristic of highly localized light emission; scintillation and wavelength shifting take place within a few tens of micrometers of the primary ionization. The new scintillator consists of a scintillating polymer base [polyvinyl toluene (PVT) or polystyrene (PS)] doped with a single wavelength shifter, 1-phenyl-3-mesityl-2-pyrazoline (PMP), which has an exceptionally large Stokes shift and therefore a comparatively small self-absorption of its emitted light. In other characteristics (e.g. scintillation efficiency and decay time) the performance of the new scintillator is similar to a good quality commercial plastic scintillator such as NE110. (orig.)

  13. Measurement of light emission in scintillation vials

    International Nuclear Information System (INIS)

    Duran Ramiro, M. Teresa; Garcia-Torano, Eduardo

    2005-01-01

    The efficiency and energy resolution of liquid scintillation counting (LSC) systems are strongly dependent on the optical characteristics of scintillators, vials, and reflectors. This article presents the results of measurements of the light-emission profile of scintillation vials. Two measurement techniques, autoradiographs and direct measurements with a photomultiplier tube, have been used to obtain light-emission distribution for standard vials of glass, etched glass and polyethylene. Results obtained with both techniques are in good agreement. For the first time, the effect of the meniscus in terms of light contribution has been numerically estimated. These results can help design LSC systems that are more efficient in terms of light collection

  14. Comparative characteristics of polystyrene scintillation strips

    International Nuclear Information System (INIS)

    Gapienko, V.A.; Denisov, A.G.; Mel'nikov, E.A.

    1992-01-01

    Results are provided for a study of the main characteristics of polystyrene scintillation strips with a cross-section of 200 x 10 mm with two different scintillation-additive compositions: 1.5% p-terphenyl + 0.01% POPOP and 1.5% p-terphenyl + 0.01% DBP. The mean light-attenuation lengths are 180 cm and 260 cm, respectively, for strips with POPOP and DBP. The emittances of the polystyrene scintillators with DBP and POPOP additives have a ratio of 0.8:1.0 as recorded by an FEU-110 photomultiplier. 2 refs., 1 fig., 2 tabs

  15. Scintillation camera with second order resolution

    International Nuclear Information System (INIS)

    Muehllehner, G.

    1976-01-01

    A scintillation camera for use in radioisotope imaging to determine the concentration of radionuclides in a two-dimensional area is described in which means is provided for second order positional resolution. The phototubes, which normally provide only a single order of resolution, are modified to provide second order positional resolution of radiation within an object positioned for viewing by the scintillation camera. The phototubes are modified in that multiple anodes are provided to receive signals from the photocathode in a manner such that each anode is particularly responsive to photoemissions from a limited portion of the photocathode. Resolution of radioactive events appearing as an output of this scintillation camera is thereby improved

  16. Factors determining radiation stability of plastic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Gunder, O.A.; Voronkina, N.I. [National Ukranian Academy of Science, Kharkov (Ukraine). Inst. for Single Crystals; Barashkov, N.N.; Milinchuk, V.K.; Jdanov, G.S. [Karpov Inst. of Physical Chemistry, Moscow (Russian Federation)

    1995-07-01

    Polystyrene (PS) and polyvinylxylene (PVX) are the base materials for plastic scintillators. UV-Vis spectrophotometry, luminescence and EPR spectroscopy were performed on irradiated samples of PS and PVX with the p-terphenyl (TP) as primary luminophore and 1,4-di-2(5-phenyloxazolyl-1,3)benzene (POPOP) as secondary one. Dependence of the radioluminescence intensity of the scintillators on the concentration of the macroradicals formed in them in the process of irradiation was investigated. Dose dependence of the radiation stability of scintillators is discussed. (Author).

  17. Factors determining radiation stability of plastic scintillators

    Science.gov (United States)

    Gunder, O. A.; Voronkina, N. I.; Barashkov, N. N.; Milinchuk, V. K.; Jdanov, G. S.

    1995-07-01

    Polystyrene (PS) and polyvinylxylene (PVX) are the base materials for plastic scintillators. UV-Vis spectrophotometry, luminescence and EPR spectroscopy were performed on irradiated samples of PS and PVX with the p-terphenyl (TP) as primary luminophore and 1,4-di-2(5-phenyloxazolyl-1,3)benzene (POPOP) as secondary one. Dependence of the radioluminescence intensity of the scintillators on the concentration of the macroradicals formed in them in the process of irradiation was investigated. Dose dependence of the radiation stability of scintillators is discussed.

  18. Factors determining radiation stability of plastic scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Barashkov, N.N. [Texas Univ., Richardson, TX (United States). Dept. of Chemistry; Gunder, O.A.; Voronkina, N.I. [National Ukrainian Academy of Science, Kharkov (Ukraine). Inst. for Single Crystals; Milinchuk, V.K. [Karpov Inst. of Physical Chemistry, Moscow (Russian Federation)

    1996-11-01

    Polystyrene (PS) and polyvinylxylene (PVX) are the base materials for plastic scintillators u.v.-Vis spectrophotometry, luminescence and ESR spectroscopy were performed on irradiated samples of PS and PVX with the p-terphenyl (TP) as the primary luminophore and 1,4-di-2(5-phenyloxazolyl-1,3) benzene (POPOP) as the secondary one. Dependence of the radioluminescence intensity of the scintillators on the concentration of the macroradicals formed by irradiation was investigated. Dose dependence of the radiation stability of scintillators is discussed. (author).

  19. Factors determining radiation stability of plastic scintillators

    International Nuclear Information System (INIS)

    Barashkov, N.N.

    1996-01-01

    Polystyrene (PS) and polyvinylxylene (PVX) are the base materials for plastic scintillators u.v.-Vis spectrophotometry, luminescence and ESR spectroscopy were performed on irradiated samples of PS and PVX with the p-terphenyl (TP) as the primary luminophore and 1,4-di-2(5-phenyloxazolyl-1,3) benzene (POPOP) as the secondary one. Dependence of the radioluminescence intensity of the scintillators on the concentration of the macroradicals formed by irradiation was investigated. Dose dependence of the radiation stability of scintillators is discussed. (author)

  20. Factors determining radiation stability of plastic scintillators

    International Nuclear Information System (INIS)

    Gunder, O.A.; Voronkina, N.I.

    1995-01-01

    Polystyrene (PS) and polyvinylxylene (PVX) are the base materials for plastic scintillators. UV-Vis spectrophotometry, luminescence and EPR spectroscopy were performed on irradiated samples of PS and PVX with the p-terphenyl (TP) as primary luminophore and 1,4-di-2(5-phenyloxazolyl-1,3)benzene (POPOP) as secondary one. Dependence of the radioluminescence intensity of the scintillators on the concentration of the macroradicals formed in them in the process of irradiation was investigated. Dose dependence of the radiation stability of scintillators is discussed. (Author)

  1. Scintillation hodoscopes on the basis of hodoscopic photomultipliers using scintillation fibers

    International Nuclear Information System (INIS)

    Alimova, T.V.; Vasil'chenko, V.G.; Vechkanov, G.N.

    1986-01-01

    Scintillation hodoscopes characteristics and their design features have been considered. The space resolution for hodoscopes consisting of 4 layers of scintillation fibres 200 mm long and 1 mm in diameter is 0.4-0.6 mm. With 2 fibres layer 1 m long and 3.8 mm in diameter the space resolution 3 mm has been obtained. A possibility to construct 0.1 mm resolution scintillation hodoscopes is discussed

  2. Long wavelength scintillators for fiber-optic applications

    International Nuclear Information System (INIS)

    Lyons, P.B.; Franks, L.; Lutz, S.; Flournoy, J.; Fullman, E.

    1980-01-01

    The use of fiber optics in plasma diagnostics has spurred the development of long wavelength scintillators with fast temporal characteristics. In this paper we describe several new liquid scintillator systems with fluorescent emissions maxima up to 730 nm. Subnanosecond scintillator FWHM response times have been obtained by the operation of liquid scintillators at elevated temperatures. Data on fiber system sensitivity versus fiber length and scintillator emission wavelength will be presented

  3. Measurement methods for several properties of scintillator

    International Nuclear Information System (INIS)

    Luo Fengqun; Ji Changsong

    1998-01-01

    The current paper describes the experimental measurement methods for the relative light output, the relative energy conversion efficiency, the intrinsic amplitude resolution and the detection efficiency of the scintillators and their temperature effects

  4. High-efficiency organic glass scintillators

    Science.gov (United States)

    Feng, Patrick L.; Carlson, Joseph S.

    2017-12-19

    A new family of neutron/gamma discriminating scintillators is disclosed that comprises stable organic glasses that may be melt-cast into transparent monoliths. These materials have been shown to provide light yields greater than solution-grown trans-stilbene crystals and efficient PSD capabilities when combined with 0.01 to 0.05% by weight of the total composition of a wavelength-shifting fluorophore. Photoluminescence measurements reveal fluorescence quantum yields that are 2 to 5 times greater than conventional plastic or liquid scintillator matrices, which accounts for the superior light yield of these glasses. The unique combination of high scintillation light-yields, efficient neutron/gamma PSD, and straightforward scale-up via melt-casting distinguishes the developed organic glasses from existing scintillators.

  5. Development of a reference liquid scintillation cocktail

    CSIR Research Space (South Africa)

    Van Wyn Gaardt, WM

    2006-02-01

    Full Text Available A reference system that would allow national laboratories to compare their activity measurements of non-gamma-emitting radionuclides at any time is currently being developed. The system requires a non-commercial reference-liquid scintillation...

  6. Permanent automatic recalibration system for scintillation camera

    International Nuclear Information System (INIS)

    Auphan, Michel.

    1974-01-01

    A permanent automatic recalibration system for a scintillation camera, of the type consisting chiefly of a collimator if necessary, a scintillator, a light guide and a network of n photomultipliers coupled to a display system, is described. It uses a device to form a single reference light signal common to all the photomultiplication lines, integrated to these latter and associated with a periodic calibration control generator. By means of associated circuits governed by the control generator the gain in each line is brought to and/or maintained at a value between fixed upper and lower limits. Steps are taken so that any gain variation in a given line is adjusted with respect to the reference light signal common to all the lines. The light signal falls preferably in the same part of the spectrum as the scintillations formed in the scintillator [fr

  7. Real-time volumetric scintillation dosimetry

    International Nuclear Information System (INIS)

    Beddar, S

    2015-01-01

    The goal of this brief review is to review the current status of real-time 3D scintillation dosimetry and what has been done so far in this area. The basic concept is to use a large volume of a scintillator material (liquid or solid) to measure or image the dose distributions from external radiation therapy (RT) beams in three dimensions. In this configuration, the scintillator material fulfills the dual role of being the detector and the phantom material in which the measurements are being performed. In this case, dose perturbations caused by the introduction of a detector within a phantom will not be at issue. All the detector configurations that have been conceived to date used a Charge-Coupled Device (CCD) camera to measure the light produced within the scintillator. In order to accurately measure the scintillation light, one must correct for various optical artefacts that arise as the light propagates from the scintillating centers through the optical chain to the CCD chip. Quenching, defined in its simplest form as a nonlinear response to high-linear energy transfer (LET) charged particles, is one of the disadvantages when such systems are used to measure the absorbed dose from high-LET particles such protons. However, correction methods that restore the linear dose response through the whole proton range have been proven to be effective for both liquid and plastic scintillators. Volumetric scintillation dosimetry has the potential to provide fast, high-resolution and accurate 3D imaging of RT dose distributions. Further research is warranted to optimize the necessary image reconstruction methods and optical corrections needed to achieve its full potential

  8. Glass scintillator pair for compensation neutron logging

    International Nuclear Information System (INIS)

    Ji Changsong; Li Xuezhi; Yiu Guangduo

    1985-01-01

    Glass scintillator pair types ST 1604 and ST 1605 for compensation of neutron logging is developed. The neutron sensitive material used is multistick lithium glass scintillators 3 and 4 mm in diameter respectively. Thermoneutron detection efficiencies are 50-60% and 100% respectively. The detection efficiency for 60 Co γ ray is lower than 0.3%. The type ST 1604 and ST 1605 may also be used as high sensitive neutron detectors in an intensive γ ray field

  9. A new technique for infrared scintillation measurements

    Energy Technology Data Exchange (ETDEWEB)

    Chiossi, F., E-mail: federico.chiossi@studenti.unipd.it [Dip. di Fisica e Astronomia and INFN, University of Padua, Via F. Marzolo 8, I-35131 Padova (Italy); Brylew, K. [Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun (Poland); Borghesani, A.F. [CNISM Unit and Dip. di Fisica e Astronomia, University of Padua, Via F. Marzolo 8, I-35131 Padova (Italy); Braggio, C.; Carugno, G. [Dip. di Fisica e Astronomia and INFN, University of Padua, Via F. Marzolo 8, I-35131 Padova (Italy); Drozdowski, W. [Institute of Physics, Faculty of Physics, Astronomy and Informatics, Nicolaus Copernicus University, Grudziadzka 5, 87-100 Torun (Poland); Guarise, M. [Dip. di Fisica e Astronomia and INFN, University of Padua, Via F. Marzolo 8, I-35131 Padova (Italy)

    2017-05-21

    We propose a new technique to measure the infrared scintillation light yield of rare earth doped crystals by comparing it to near UV–visible scintillation of a calibrated Pr:(Lu{sub 0.75}Y{sub 0.25}){sub 3}Al{sub 5}O{sub 12} sample. As an example, we apply this technique to provide the light yield in visible and infrared range up to 1700 nm of this crystal.

  10. Composition for use in scintillator systems

    International Nuclear Information System (INIS)

    Tarkkanen, V.

    1976-01-01

    A liquid scintillation counting composition of the type comprising an aromatic hydrocarbon solvent, an ethoxylated alkyl phenol surfactant, and a scintillation solute, containing a small amount of a substituted ethoxylated carboxylate acid and/or a tertiary amine salt or a quaternary ammonium salt of such acid is described. The free acid reduces chemiluminescence upon the addition of an alkaline sample to the composition, while the tertiary amine or quaternary ammonium salt enhances the water miscibility of the composition

  11. Coping with plastic scintillators in nuclear safeguards

    International Nuclear Information System (INIS)

    Fehlau, P.E.; Brunson, G.S.

    1983-01-01

    Plastic scintillators offer several advantages for nuclear safeguards research and technology to those who design, assemble, encapsulate, and calibrate detectors from raw materials that are commercially available. These large, inexpensive detectors have good spatial uniformity and good high-energy gamma-ray response. Uniform light collection is obtained with a light pipe attached to a polished scintillator wrapped with aluminum foil. Best low-energy response is obtained by applying a variance analyzer to select the low energy bias level

  12. A new technique for infrared scintillation measurements

    International Nuclear Information System (INIS)

    Chiossi, F.; Brylew, K.; Borghesani, A.F.; Braggio, C.; Carugno, G.; Drozdowski, W.; Guarise, M.

    2017-01-01

    We propose a new technique to measure the infrared scintillation light yield of rare earth doped crystals by comparing it to near UV–visible scintillation of a calibrated Pr:(Lu_0_._7_5Y_0_._2_5)_3Al_5O_1_2 sample. As an example, we apply this technique to provide the light yield in visible and infrared range up to 1700 nm of this crystal.

  13. Survey meter using novel inorganic scintillators

    International Nuclear Information System (INIS)

    Yoshikawa, Akira; Fukuda, Kentaro; Kawaguchi, Noriaki; Kamada, Kei; Fujimoto, Yutaka; Yokota, Yuui; Kurosawa, Shunsuke; Yanagida, Takayuki

    2012-01-01

    Single crystal scintillator materials are widely used for detection of high-energy photons and particles. There is continuous demand for new scintillator materials with higher performance because of increasing number of medical, industrial, security and other applications. This article presents the recent development of three novel inorganic scintillators; Pr-doped Lu 3 Al 5 O 12 (Pr:LuAG), Ce doped Gd 3 (Al, Ga) 5 O 12 (Ce:GAGG) and Ce or Eu-doped 6 LiCaAlF 6 (Ce:LiCAF, Eu:LiCAF). Pr:LuAG shows very interesting scintillation properties including very fast decay time, high light yield and excellent energy resolution. Taking the advantage of these properties, positron emission mammography (PEM) equipped with Pr:LuAG were developed. Ce:GAGG shows very high light yield, which is much higher than that of Ce:LYSO. Survey meter using Ce:GAGG is developed using this scintillator. Ce:LiCAF and Eu:LiCAF were developed for neutron detection. The advantage and disadvantage are discussed comparing with halide scintillators. Eu-doped LiCAF indicated five times higher light yield than that of existing Li-glass. It is expected to be used as the alternative of 3 He. (author)

  14. (Alpha-) quenching temperature dependence in liquid scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, Arnd; Lozza, Valentina; Krosigk, Belina von; Zuber, Kai [Institut fuer Kern- und Teilchenphysik, TU Dresden (Germany)

    2015-07-01

    Liquid scintillator (LS) is an effective and promising detector material, which is and will be used by many small and large scale experiments. In order to perform correct signal identification and background suppression, a very good knowledge of LS properties is crucial. One of those is the light yield from alpha particles in liquid scintillator. This light output strongly quenched, approx. 10 times compared to that of electrons, and has been precisely studied at room temperature for various LS. Big scintillator experiments, such as SNO+ and maybe future large scale detectors, will operate at different temperatures. While a strong temperature dependence is well known for solid state scintillators, due to the different scintillation process, a quenching temperature dependence in LS is usually assumed negligible. On the other hand, inconsistencies in between measurements are often explained by potential temperature effects. This study investigates LAB based liquid scintillator with an intrinsic, dissolved alpha emitter and its behaviour with temperature change. In a small, cooled and heated setup, a stabilized read-out with two PMTs is realised. First results are presented.

  15. A gamma-ray discriminating neutron scintillator

    International Nuclear Information System (INIS)

    Eschbach, P.A.; Miller, S.D.; Cole, M.C.

    1994-01-01

    A neutron scintillator has been developed at Pacific Northwest Laboratory which responds directly to as little as 10 mrem/hour dose equivalent rate fast neutron fields. The scintillator is composed of CaF 2 :Eu or of NaI grains within a silicone rubber or polystyrene matrix, respectively. Neutrons colliding with the plastic matrix provide knockon protons, which in turn deposit energy within the grains of phosphor to produce pulses of light. Neutron interactions are discriminated from gamma-ray events on the basis of pulse height. Unlike NE-213 liquid scintillators, this solid scintillator requires no pulseshape discrimination and therefore requires less hardware. Neutron events are anywhere from two to three times larger than the gamma-ray exposures are compared to 0.7 MeV gamma-ray exposures. The CaF 2 :Eu/silicone rubber scintillator is nearly optically transparent, and can be made into a very sizable detector (4 cm x 1.5 cm) without degrading pulse height. This CaF 2 :Eu scintillator has been observed to have an absolute efficiency of 0.1% when exposed to 5-MeV accelerator-generated neutrons (where the absolute efficiency is the ratio of observed neutron events divided by the number of fast neutrons striking the detector)

  16. Evidência molecular da ocorrência de um fitoplasma associado ao lenho mole da macieira Molecular evidence for an association of a phytoplasma with apple rubbery wood

    Directory of Open Access Journals (Sweden)

    Luiz Fernando Caldeira Ribeiro

    2007-03-01

    Full Text Available O lenho mole da macieira é uma doença relevante em diversas partes do mundo. Sintomas típicos desta doença têm sido observados em pomares instalados em estados do sul do território brasileiro desde a década de oitenta. Enxertia tem revelado a natureza infecciosa da doença e a observação de corpúsculos filamentosos no floema tem evidenciado possível associação com fitoplasma. No presente trabalho plantas com sintomas de lenho mole foram coletadas em pomar comercial, visando demonstrar a presença de fitoplasma em tecido doente, bem como identificar molecularmente este fitoplasma. Através do emprego de duplo PCR com iniciadores universais R16mF2/R1 e R16F2n/R2, fitoplasma foi consistentemente detectado em plantas sintomáticas. A identificação conduzida com duplo PCR usando-se iniciadores específicos R16(IIIF2/R demonstrou que o fitoplasma detectado pertencia ao grupo 16SrIII. Análises de RFLP conduzidas com as endonucleases AluI, KpnI, HinfI, HpaII, MseI, RsaI e SauIIIA confirmaram que o fitoplasma era um representante típico do grupo 16SrIII. A detecção e identificação molecular se constitui numa forte evidência que um fitoplasma está associado ao lenho mole da macieira no Brasil, complementando os trabalhos realizados anteriormente com transmissão por enxertia e observação por microscopia eletrônica .Apple rubbery wood is an important disease occurring worldwide. Typical symptoms have been observed since 80' decade in orchards located in the South part of Brazil. In previous studies, grafting has evidenciated that the disease had infeccious etiology and visualization of filamentous bodies inside phloem had indicated that a phytoplasma could be associated with the disease. In the present study, plants with symptoms of rubbery wood were sampled in a commercial orchard in order to demonstrate the presence of phytoplasma in infected tissue and to identify molecularly that the organism. Using nested PCR with universal

  17. Conference on Engineering of Scintillation Materials and Radiation Technologies

    CERN Document Server

    Gektin, Alexander

    2017-01-01

    This volume provides a broad overview of the latest achievements in scintillator development, from theory to applications, and aiming for a deeper understanding of fundamental processes, as well as the discovery and availability of components for the production of new generations of scintillation materials. It includes papers on the microtheory of scintillation and the initial phase of luminescence development, applications of the various materials, and development and characterization of ionizing radiation detection equipment. The book also touches upon the increased demand for cryogenic scintillators, the renaissance of  garnet materials for scintillator applications, nano-structuring in scintillator development, development and applications for security, and exploration of hydrocarbons and ecological monitoring.

  18. Role of hot electron transport in scintillators: A theoretical study

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Huihui [SZU-NUS Collaborative Innovation Center for Optoelectronic Science and Technology, Key Lab. of Optoelectronic Devices and Systems of Ministry of Education and Guangdong Province, College of Optoelectronic Engineering, Shenzhen Univ. (China); Li, Qi [Physical Sciences Division, IBM TJ Watson Research Center, Yorktown Heights, NY (United States); Department of Computer Science, University of Illinois at Urbana-Champaign, Urbana, IL (United States); Lu, Xinfu; Williams, R.T. [Department of Physics, Wake Forest University, Winston Salem, NC (United States); Qian, Yiyang [College of Engineering and Applied Science, Nanjing University (China); Wu, Yuntao [Scintillation Materials Research Center, University of Tennessee, Knoxville, TN (United States)

    2016-10-15

    Despite recent intensive study on scintillators, several fundamental questions on scintillator properties are still unknown. In this work, we use ab-initio calculations to determine the energy dependent group velocity of the hot electrons from the electronic structures of several typical scintillators. Based on the calculated group velocities and optical phonon frequencies, a Monte-Carlo simulation of hot electron transport in scintillators is carried out to calculate the thermalization time and diffusion range in selected scintillators. Our simulations provide physical insights on a recent trend of improved proportionality and light yield from mixed halide scintillators. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  19. Fast determination of Ziziphora tenuior L. essential oil by inorganic-organic hybrid material based on ZnO nanoparticles anchored to a composite made from polythiophene and hexagonally ordered silica.

    Science.gov (United States)

    Piryaei, Marzieh; Abolghasemi, Mir Mahdi; Nazemiyeh, Hossein

    2015-01-01

    In this paper, for the first time, an inorganic-organic hybrid material based on ZnO nanoparticles was anchored to a composite made from polythiophene and hexagonally ordered silica (ZnO/PT/SBA-15) for use in solid-phase fibre microextraction (SPME) of medicinal plants. A homemade SPME apparatus was used for the extraction of volatile components of Ziziphora tenuior L. A simplex method was used for optimisation of five different parameters affecting the efficiency of the extraction. The main constituents extracted by ZnO/PT/SBA-15 and PDMS fibres and hydrodistillation (HD) methods, respectively, included pulegone (51.25%, 53.64% and 56.68%), limonene (6.73%, 6.58% and 8.3%), caryophyllene oxide (5.33%, 4.31% and 4.53%) and 1,8-cineole (4.21%, 3.31% and 3.18%). In comparison with the HD method, the proposed technique could equally monitor almost all the components of the sample, in an easier way, in a shorter time and requiring a much lower amount of the sample.

  20. Single and multi-component adsorption of salicylic acid, clofibric acid, carbamazepine and caffeine from water onto transition metal modified and partially calcined inorganic-organic pillared clay fixed beds.

    Science.gov (United States)

    Cabrera-Lafaurie, Wilman A; Román, Félix R; Hernández-Maldonado, Arturo J

    2015-01-23

    Fixed-beds of transition metal (Co(2+), Ni(2+) or Cu(2+)) inorganic-organic pillared clays (IOCs) were prepared to study single- and multi-component non-equilibrium adsorption of a set of pharmaceutical and personal care products (PPCPs: salicylic acid, clofibric acid, carbamazepine and caffeine) from water. Adsorption capacities for single components revealed that the copper(II) IOCs have better affinity toward salicylic and clofibric acid. However, multi-component adsorption tests showed a considerable decrease in adsorption capacity for the acids and an unusual selectivity toward carbamazepine depending on the transition metal. This was attributed to a combination of competition between PPCPs for adsorption sites, adsorbate-adsorbate interactions, and plausible pore blocking caused by carbamazepine. The cobalt(II) IOC bed that was partially calcined to fractionate the surfactant moiety showcased the best selectivity toward caffeine, even during multi-component adsorption. This was due to a combination of a mildly hydrophobic surface and interaction between the PPCP and cobalt(II). In general, the tests suggest that these IOCs may be a potential solution for the removal of PPCPs if employed in a layered-bed configuration, to take care of families of adsorbates in a sequence that would produce sharpened concentration wavefronts. Copyright © 2014 Elsevier B.V. All rights reserved.

  1. Inorganic-organic hybrid structure: Synthesis, structure and magnetic properties of a cobalt phosphite-oxalate, [C4N2H12][Co4(HPO3)2(C2O4)3

    International Nuclear Information System (INIS)

    Mandal, Sukhendu; Natarajan, Srinivasan

    2005-01-01

    A hydrothermal reaction of a mixture of cobalt (II) oxalate, phosphorous acid, piperazine and water at 150 o C for 96h followed by heating at 180 o C for 24h gave rise to a new inorganic-organic hybrid solid, [C 4 N 2 H 12 ][Co 4 (HPO 3 ) 2 (C 2 O 4 ) 3 ], I. The structure consists of edge-shared CoO 6 octahedra forming a [Co 2 O 10 ] dimers that are connected by HPO 3 and C 2 O 4 units forming a three-dimensional structure with one-dimensional channels. The amine molecules are positioned within these channels. The oxalate units have a dual role of connecting within the plane of the layer as well as out of the plane. Magnetic susceptibility measurement shows the compound orders antiferromagnetically at low temperature (T N =22K). Crystal data: I, monoclinic, space group=P2 1 /c (No. 14). a=7.614(15), b=7.514(14), c=17.750(3)A, β=97.351(3) o , V=1007.30(3)A 3 , Z=2, ρ calc =2.466g/cm 3 , μ (MoKα) =3.496mm -1 , R 1 =0.0310 and wR 2 =0.0807 data [I>2σ(I)

  2. Scintillation Detectors for Charged Particles and Photons

    CERN Document Server

    Lecoq, P

    2011-01-01

    Scintillation Detectors for Charged Particles and Photons in 'Charged Particle Detectors - Particle Detectors and Detector Systems', part of 'Landolt-Börnstein - Group I Elementary Particles, Nuclei and Atoms: Numerical Data and Functional Relationships in Science and Technology, Volume 21B1: Detectors for Particles and Radiation. Part 1: Principles and Methods'. This document is part of Part 1 'Principles and Methods' of Subvolume B 'Detectors for Particles and Radiation' of Volume 21 'Elementary Particles' of Landolt-Börnstein - Group I 'Elementary Particles, Nuclei and Atoms'. It contains the Subsection '3.1.1 Scintillation Detectors for Charged Particles and Photons' of Section '3.1 Charged Particle Detectors' of Chapter '3 Particle Detectors and Detector Systems' with the content: 3.1.1 Scintillation Detectors for Charged Particles and Photons 3.1.1.1 Basic detector principles and scintillator requirements 3.1.1.1.1 Interaction of ionizing radiation with scintillator material 3.1.1.1.2 Important scint...

  3. Radioactivity measurements by liquid scintillation spectroscopy

    International Nuclear Information System (INIS)

    Cassette, Ph.

    2004-01-01

    The activity measurement techniques by liquid scintillation spectroscopy consist to mix the radioactive solution to measure with a scintillating liquid and to transform the ionizing radiations, resulting from decays, into light, detectable and quantifiable. The main advantages of these techniques are the easiness of preparation of the radioactive sources, the geometric efficiency of detection of 4π and the possibility of detection of low-level energy radiations. There are one of the only methods giving the possibility to measure the activity of pure β radionuclides; indeed, the nuclear disintegration is not accompanied of gamma radiations detectable by other techniques. There are one of the only methods too of measurement of radionuclides which disintegrate by electron capture and especially those leading to the emission of low-level energy ionizing radiations. Liquid scintillation spectroscopy can be used as an absolute method of activity measurement that is to say without the use of a calibration standard. The modern liquid scintillation counting devices can be very sensitive; the measurement of micro-activities being possible. Some of the applications of these activity measurement techniques are the carbon 14 dating and the geological tracing. Their main disadvantage is the global energetic yield which is low and variable in terms of the composition of the scintillation source necessitating to calculate the detection yield for each condition of measurement. (O.M.)

  4. Analysis of low-intensity scintillation spectra

    International Nuclear Information System (INIS)

    Muravsky, V.; Tolstov, S.A.

    2002-01-01

    The maximum likelihood algorithms for nuclides activities estimation from low intensity scintillation γ-ray spectra have been created. The algorithms treat full energy peaks and Compton parts of spectra, and they are more effective than least squares estimators. The factors that could lead to the bias of activity estimates are taken into account. Theoretical analysis of the problem of choosing the optimal set of initial spectra for the spectrum model to minimize errors of the activities estimation has been carried out for the general case of the N-components with Gaussian or Poisson statistics. The obtained criterion allows to exclude superfluous initial spectra of nuclides from the model. A special calibration procedure for scintillation γ-spectrometers has been developed. This procedure is required for application of the maximum likelihood activity estimators processing all the channels of the scintillation γ-spectrum, including the Compton part. It allows one to take into account the influence of the sample mass density variation. The algorithm for testing the spectrum model adequacy to the processed scintillation spectrum has been developed. The algorithms are realized in Borland Pascal 7 as a library of procedures and functions. The developed library is compatible with Delphi 1.0 and higher versions. It can be used as the algorithmic basis for analysis of highly sensitive scintillation γ- and β-spectrometric devices. (author)

  5. Solid scintillator 'Ready Cap' for measurement with a liquid scintillation counter

    International Nuclear Information System (INIS)

    Ijiri, Kenichi; Endo, Masashi; Nogawa, Norio; Tsuda, Shoko; Nakamura, Aiko; Morikawa, Naotake; Osaki, Susumu.

    1990-01-01

    'Ready Cap', a small plastic container coated with solid scintillator has recently been introduced (Beckman Instruments, Inc.). Pulse height spectra and counting efficiencies obtained with a liquid scintillator and Ready Cap using a liquid scintillation counter were compared for 15 different radionuclides. For radionuclides emitting low-energy β-rays or characteristic X-rays, the spectra for Ready Cap shifted toward the higher energy side compared with the spectra for the liquid scintillator. This tendency was reversed for the nuclides emitting higher-energy β-radiations ( 36 Cl and 32 P). Generally, counting efficiencies both in Ready Cap and in liquid scintillator increased with increase in the energy of β- or X-rays. For some nuclides, Ready Cap gave higher counting efficiencies and for others it gave lower values than in the liquid scintillator. However, the differences were not large within each nuclide. The use of Ready Cap is recommended for measurements of radionuclides when liquid scintillation cocktails have no means of waste disposal under the present Japanese radioisotope regulation. (author)

  6. Radiation imaging with a new scintillator and a CMOS camera

    Czech Academy of Sciences Publication Activity Database

    Kurosawa, S.; Shoji, Y.; Pejchal, Jan; Yokota, Y.; Yoshikawa, A.

    2015-01-01

    Roč. 9, Jul (2015), C07015 ISSN 1748-0221 Institutional support: RVO:68378271 Keywords : scintillators * scintillation and light emission processes * image processin Subject RIV: BL - Plasma and Gas Discharge Physics Impact factor: 1.310, year: 2015

  7. Plastic scintillator-based hodoscope for the characterization of large ...

    Indian Academy of Sciences (India)

    Plastic scintillator-based hodoscope for the characterization of large-area resistive plate chambers. V K S KASHYAP C YADAV ... Keywords. Plastic scintillators; resistive plate chambers. ... Pramana – Journal of Physics | News. © 2017 Indian ...

  8. Collimated trans-axial tomographic scintillation camera

    International Nuclear Information System (INIS)

    1980-01-01

    The objects of this invention are first to reduce the time required to obtain statistically significant data in trans-axial tomographic radioisotope scanning using a scintillation camera. Secondly, to provide a scintillation camera system to increase the rate of acceptance of radioactive events to contribute to the positional information obtainable from a known radiation source without sacrificing spatial resolution. Thirdly to reduce the scanning time without loss of image clarity. The system described comprises a scintillation camera detector, means for moving this in orbit about a cranial-caudal axis relative to a patient and a collimator having septa defining apertures such that gamma rays perpendicular to the axis are admitted with high spatial resolution, parallel to the axis with low resolution. The septa may be made of strips of lead. Detailed descriptions are given. (U.K.)

  9. Scintillation γ spectrography. Physical principles. Apparatus. Operation

    International Nuclear Information System (INIS)

    Julliot, C.

    1960-01-01

    The scintillation detector forms the main part of the instrument used, the electronic unit presenting the results produced. After a brief description of the process of γ photon absorption in the material, the particular case of NaI (T1), the scintillator used, is examined. The intensity of the scintillation caused by γ ray absorption and the characteristics of the photomultiplier play a determining part in the energy resolution of the instrument. For the γ recording spectrograph, we show to what extent the technique for using the electronic unit can modify the results. A detailed description is given of the activity measurement of a γ-emitting radioelement by the spectrographic method. (author) [fr

  10. Proportional gas scintillation detectors and their applications

    International Nuclear Information System (INIS)

    Petr, I.

    1978-01-01

    The principle is described of a gas proportional scintillation detector and its function. Dependence of Si(Li) and xenon proportional detectors energy resolution on the input window size is given. A typical design is shown of a xenon detector used for X-ray spetrometry at an energy of 277 eV to 5.898 keV and at a gas pressure of 98 to 270 kPa. Gas proportional scintillation detectors show considerable better energy resolution than common proportional counters and even better resolution than semiconductor Si(Li) detectors for low X radiation energies. For detection areas smaller than 25 mm 2 Si(Li) detectors show better resolution, especially for higher X radiation energies. For window areas 25 to 190 mm 2 both types of detectors are equal, for a window area exceeding 190 mm 2 the proportional scintillation detector has higher energy resolution. (B.S.)

  11. Scintillation camera with improved output means

    International Nuclear Information System (INIS)

    Lange, K.; Wiesen, E.J.; Woronowicz, E.M.

    1978-01-01

    In a scintillation camera system, the output pulse signals from an array of photomultiplier tubes are coupled to the inputs of individual preamplifiers. The preamplifier output signals are coupled to circuitry for computing the x and y coordinates of the scintillations. A cathode ray oscilloscope is used to form an image corresponding with the pattern in which radiation is emitted by a body. Means for improving the uniformity and resolution of the scintillations are provided. The means comprise biasing means coupled to the outputs of selected preamplifiers so that output signals below a predetermined amplitude are not suppressed and signals falling within increasing ranges of amplitudes are increasingly suppressed. In effect, the biasing means make the preamplifiers non-linear for selected signal levels

  12. Scintillation counting: an extrapolation into the future

    International Nuclear Information System (INIS)

    Ross, H.H.

    1983-01-01

    Progress in scintillation counting is intimately related to advances in a variety of other disciplines such as photochemistry, photophysics, and instrumentation. And while there is steady progress in the understanding of luminescent phenomena, there is a virtual explosion in the application of semiconductor technology to detectors, counting systems, and data processing. The exponential growth of this technology has had, and will continue to have, a profound effect on the art of scintillation spectroscopy. This paper will review key events in technology that have had an impact on the development of scintillation science (solid and liquid) and will attempt to extrapolate future directions based on existing and projected capability in associated fields. Along the way there have been occasional pitfalls and several false starts; these too will be discussed as a reminder that if you want the future to be different than the past, study the past

  13. Current trends in scintillator detectors and materials

    International Nuclear Information System (INIS)

    Moses, W.W.

    2002-01-01

    The last decade has seen a renaissance in inorganic scintillator development for gamma ray detection. Lead tungstate (PbWO 4 ) has been developed for high-energy physics experiments, and possesses exceptionally high density and radiation hardness, albeit with low luminous efficiency. Lutetium orthosilicate or LSO (Lu 2 SiO 5 :Ce) possesses a unique combination of high luminous efficiency, high density, and reasonably short decay time, and is now incorporated in commercial positron emission tomography cameras. There have been advances in understanding the fundamental mechanisms that limit energy resolution, and several recently discovered materials (such as LaBr 3 :Ce) possess energy resolution that approaches that of direct solid state detectors. Finally, there are indications that a neglected class of scintillator materials that exhibit near band-edge fluorescence could provide scintillators with sub-nanosecond decay times and high luminescent efficiency

  14. Optics study of liquid scintillation counting systems

    International Nuclear Information System (INIS)

    Duran Ramiro, M. T.; Garcia-Torano, E.

    2005-01-01

    Optics is a key issue in the development of any liquid scintillation counting (LSC) system. Light emission in the scintillating solution, transmission through the vial and reflector design are some aspects that need to be considered in detail. This paper describes measurements and calculations carried out to optimise these factors for the design of a new family of LSC counters. Measurements of the light distribution emitted by a scintillation vial were done by autoradiographs of cylindrical vials made of various materials and results were compared to those obtained by direct measurements of the light distribution made by scanning the vial with a photomultiplier tube. Calculations were also carried out to study the light transmission in the vial and the optimal design of the reflector for a system with one photomultiplier tube. (Author)

  15. The Origins of Scintillator Non-Proportionality

    Science.gov (United States)

    Moses, W. W.; Bizarri, G. A.; Williams, R. T.; Payne, S. A.; Vasil'ev, A. N.; Singh, J.; Li, Q.; Grim, J. Q.; Choong, W.-S.

    2012-10-01

    Recent years have seen significant advances in both theoretically understanding and mathematically modeling the underlying causes of scintillator non-proportionality. The core cause is that the interaction of radiation with matter invariably leads to a non-uniform ionization density in the scintillator, coupled with the fact that the light yield depends on the ionization density. The mechanisms that lead to the luminescence dependence on ionization density are incompletely understood, but several important features have been identified, notably Auger-like processes (where two carriers of excitation interact with each other, causing one to de-excite non-radiatively), the inability of excitation carriers to recombine (caused either by trapping or physical separation), and the carrier mobility. This paper reviews the present understanding of the fundamental origins of scintillator non-proportionality, specifically the various theories that have been used to explain non-proportionality.

  16. The MICE scintillating-fibre tracker

    Energy Technology Data Exchange (ETDEWEB)

    Matsushita, T [Imperial College London (United Kingdom)], E-mail: T.Matsushita@imperial.ac.uk

    2008-06-15

    The international Muon Ionization Cooling Experiment (MICE) collaboration will carry out a systematic investigation of the ionization cooling of a muon beam. An ionization cooling channel is required to compress the phase-space volume occupied by the muon beam prior to acceleration in the baseline conceptual designs for both the Neutrino Factory and the Muon Collider. Muons entering and leaving the cooling channel will be measured in two solenoidal spectrometers, each of which is instrumented with a scintillating-fibre tracker. Each tracker is composed of five planar scintillating fibre stations, each station being composed of three planar layers of 350 micron scintillating fibres. The devices will be read out using the Visible Light Photon Counters (VLPCs) developed for use in the D0 experiment at the Tevatron. The design of the system will be presented along with the status of the tracker-construction project. The expected performance of prototypes of the full tracker will be summarised.

  17. Microfluidic Scintillation Detectors for High Energy Physics

    CERN Document Server

    Maoddi, Pietro; Mapelli, Alessandro

    This thesis deals with the development and study of microfluidic scintillation detectors, a technology of recent introduction for the detection of high energy particles. Most of the interest for such devices comes from the use of a liquid scintillator, which entails the possibility of changing the active material in the detector, leading to increased radiation resistance. A first part of the thesis focuses on the work performed in terms of design and modelling studies of novel prototype devices, hinting to new possibilities and applications. In this framework, the simulations performed to validate selected designs and the main technological choices made in view of their fabrication are addressed. The second part of this thesis deals with the microfabrication of several prototype devices. Two different materials were studied for the manufacturing of microfluidic scintillation detectors, namely the SU-8 photosensitive epoxy and monocrystalline silicon. For what concerns the former, an original fabrication appro...

  18. BC-454 boron-loaded plastic scintillator

    International Nuclear Information System (INIS)

    Bellian, J.G.

    1984-01-01

    Prototype samples of plastic scintillators containing up to 10% by weight of natural boron have been produced. The maximum size scintillators made to date are 28 mm dia. x 100 mm long. Rods containing up to 2% boron are now made routinely and work is progressing on higher concentrations. The plastics are clear and emit the same blue fluorescence as other common plastic scintillators. It is expected that rods up to 3'' dia. containing 5% boron will be produced during the next few months. BC-454 is particularly useful in neutron research, materials studies, some types of neutron dosimetry, and monitoring of medium to high energy neutrons in the presence of other types radiation. It combines attractive features that enhance its usefulness to the physics community

  19. Scintillation camera with second order resolution

    International Nuclear Information System (INIS)

    1975-01-01

    A scintillation camera is described for use in radioisotope imaging to determine the concentration of radionuclides in a two-dimensional area in which means is provided for second-order positional resolution. The phototubes which normally provide only a single order of resolution, are modified to provide second-order positional resolution of radiation within an object positioned for viewing by the scintillation camera. The phototubes are modified in that multiple anodes are provided to receive signals from the photocathode in a manner such that each anode is particularly responsive to photoemissions from a limited portion of the photocathode. Resolution of radioactive events appearing as an output of this scintillation camera is thereby improved

  20. Radiocarbon dating methods using benzene liquid scintillation

    International Nuclear Information System (INIS)

    Togashi, Shigeko; Matsumoto, Eiji

    1983-01-01

    The radiocarbon dating method using benzene liquid scintillation is reported in detail. The results of measurement of NBS oxalic acid agree with the recommended value, indicating that isotopic fractionation during benzene synthesis can be negligible. Ten samples which have been already measured by gas counter are dated by benzene liquid scintillation. There is no significant difference in age for the same sample between benzene liquid scintillation and gas counters. It is shown that quenching has to be corrected for the young sample. Memory effect in stainless steel reaction vessel can be removed by using an exchangeable inner vessel and by baking it in the air. Using this method, the oldest age that can be measured with 2.3 g carbon is 40,000 years B.P. (author)

  1. Time resolution measurements with an improved discriminator and conical scintillators

    International Nuclear Information System (INIS)

    McGervey, J.D.; Vogel, J.; Sen, P.; Knox, C.

    1977-01-01

    A new constant fraction discriminator with improved stability and walk characteristics is described. The discriminator was used with RCA C31024 photomultiplier tubes to test scintillators of conical and cylindrical shapes. Conical scintillators of 2.54 cm base diameter, 1.0 cm top diameter, and 2.54 cm height gave a fwhm of 155 ps for 60 Co gamma rays; larger conical scintillators gave an improvement of 10-15% in fwhm over cylindrical scintillators of equal volume. (Auth.)

  2. The measurement of temperature effect of light output of scintillators

    International Nuclear Information System (INIS)

    Ji Changsong; Zhou Zaiping; Zhang Longfang

    1999-01-01

    The author describes a experiment equipment used for measurement of temperature effect of light output of scintillators; gives some measurement results of temperature effect of light output for NaI(Tl), CsI(Tl), plastic scintillator, ZnS(Ag), anthracene crystal glass scintillator; analyzes the error factors affecting the measurement results. The total uncertainty of the temperature effect measurement for NaI(Tl) and plastic scintillator is 11%

  3. Applications of low level liquid scintillation counting

    International Nuclear Information System (INIS)

    Noakes, J.E.

    1983-01-01

    Low level liquid scintillation counting is reviewed in terms of its present use and capabilities for measuring low activity samples. New areas of application of the method are discussed with special interest directed to the food industry and environmental monitoring. Advantages offered in the use of a low background liquid scintillation counter for the nuclear power industry and nuclear navy are discussed. Attention is drawn to the need for commercial development of such instrumentation to enable wider use of the method. A user clientele is suggested as is the required technology to create such a counter

  4. Cosmic ray spectroscopy using plastic scintillator detector

    International Nuclear Information System (INIS)

    Rudra, Sharmili; Nandan, Akhilesh P.; Neog, Himangshu; Biswas, S.; Mohanty, B.; Mahapatra, S.; Samal, P.K.

    2014-01-01

    A simple and new technique has been developed using plastic scintillator detectors for cosmic ray spectroscopy without single channel analyzer (SCA) or multichannel analyzer (MCA). In this technique only a leading edge discriminator (LED) and a NIM scaler have been used. Plastic scintillator detectors has been used to measure the velocity of cosmic ray muons. Here the time difference has been measured from the Tektronix DPO 5054 digital phosphor oscilloscope with 500 MHz and 5 GS/s. The details of experimental technique, analysis procedure and experimental results are presented

  5. Near-infrared scintillation of liquid argon

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, T. [Fermilab; Escobar, C. O. [Campinas State U.; Lippincott, W. H. [Fermilab; Rubinov, P. [Fermilab

    2016-03-03

    Since the 1970s it has been known that noble gases scintillate in the near infrared (NIR) region of the spectrum (0.7 $\\mu$m < $\\lambda$; < 1.5$\\mu$m). More controversial has been the question of the NIR light yield for condensed noble gases. We first present the motivation for using the NIR scintillation in liquid argon detectors, then briefly review early as well as more recent efforts and finally show encouraging preliminary results of a test performed at Fermilab.

  6. Scintillation camera for high activity sources

    International Nuclear Information System (INIS)

    Arseneau, R.E.

    1978-01-01

    The invention described relates to a scintillation camera used for clinical medical diagnosis. Advanced recognition of many unacceptable pulses allows the scintillation camera to discard such pulses at an early stage in processing. This frees the camera to process a greater number of pulses of interest within a given period of time. Temporary buffer storage allows the camera to accommodate pulses received at a rate in excess of its maximum rated capability due to statistical fluctuations in the level of radioactivity of the radiation source measured. (U.K.)

  7. Pulse shape discrimination with scintillation detectors

    International Nuclear Information System (INIS)

    Winyard, R.A.

    A quantitative study of pulse shape discrimination with scintillation counters has been undertaken using a crossover timing technique. The scintillators investigated included experimental and commercial liquids and plastics in addition to inorganic phosphors. The versatility of the pulse shape discrimination system has been demonstrated by extending the measurements to investigate phoswiches and liquids loaded with radioactive materials and by its application to the suppression of unwanted backgrounds in delayed coincidence counting for the measurement of nuclear half-lives and isotope identification have been carried out. (author)

  8. Effects of radiation on scintillating fiber performance

    International Nuclear Information System (INIS)

    Bauer, M.L.; Cohn, H.; Efremenko, Yu.; Gordeev, A.; Kamyshkov, Yu.; Onopienko, D.; Savin, S.; Shmakov, K.; Tarkovsky, E.; Young, K.G.; Carey, R.; Rothman, M.; Sulak, L.; Worstell, W.; Parr, H.

    1992-01-01

    Continued rapid improvements in formulations for scintillating fibers require the ability to parameterize and predict effects of radiation on detector performance. Experimental techniques necessary to obtain needed information and calculational procedures used in performing predications for hadron scintillating fiber calorimetry in the Superconducting Supercollider environment are described. The experimental techniques involve control of the testing environment, consideration of dose rate effects, and other factors. These calculations involve the behavior of particle showers in the detector, expected levels of radiation, and parameterization of the radiation effects. A summary of significant work is also presented

  9. Effects of radiation on scintillating fiber performance

    International Nuclear Information System (INIS)

    Young, K.G.; Bauer, M.L.; Cohn, H.; Efremenko, Yu.; Gordeev, A.; Kamyshkov, Yu.; Onopienko, D.; Savin, S.; Shmakov, K.; Tarkovsky, E.; Carey, R.; Rothman, M.; Sulak, L.; Worstell, W.; Paar, H.

    1993-01-01

    Continued rapid improvements in formulations for scintillating fibers require the ability to parameterize and predict effects of radiation on detector performance. Experimental techniques necessary to obtain desired information and calculational procedures used in performing predictions for hadron scintillating fiber calorimetry in the Superconducting Supercollider environment are described. The experimental techniques involve control of the testing environment, consideration of dose rate effects, and other factors. The calculations involve the behavior of particle showers in the detector, expected levels of radiation, and parameterization of the radiation effects. A summary of significant work is also presented

  10. Luminescence and scintillation properties of rare-earth-doped LuF.sub.3./sub. scintillation crystals

    Czech Academy of Sciences Publication Activity Database

    Pejchal, Jan; Fukuda, K.; Kurosawa, S.; Yokota, Y.; Yoshikawa, A.

    2015-01-01

    Roč. 41, Mar SI (2015), s. 58-62 ISSN 0925-3467 Institutional support: RVO:68378271 Keywords : lutetium fluoride * scintillator * scintillator * VUV luminescence Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.183, year: 2015

  11. International Colloquium on Scattering and Scintillation in Radio Astronomy

    CERN Document Server

    Coles, W A; Rickett, B J; Bird, M K; Efimov, A I; Samoznaev, L N; Rudash, V K; Chashei, I V; Plettemeier, D; Spangler, S R; Tokarev, Y; Belov, Y; Boiko, G; Komrakov, G; Chau, J; Harmon, J; Sulzer, M; Kojima, M; Tokumaru, M; Fujiki, K; Janardhan, P; Jackson, B V; Hick, P P; Buffington, A; Olyak, M R; Fallows, R A; Nechaeva, M B; Gavrilenko, V G; Gorshenkov, Yu N; Alimov, V A; Molotov, I E; Pushkarev, A B; Shanks, R; Tuccari, G; Lotova, N A; Vladimirski, K V; Obridko, V N; Gubenko, V N; Andreev, V E; Stinebring, D R; Gwinn, C; Lovell, J E J; Jauncey, D L; Senkbeil, C; Shabala, S; Bignall, H E; MacQuart, J P; Kedziora-Chudczer, L; Smirnova, T V; Malofeev, V M; Malov, O I; Tyulbashev, S A; Jessner, A; Sieber, W; Wielebinski, R; Scattering and Scintillation in Radio Astronomy

    2006-01-01

    Topics of the Colloquium: a) Interplanetary scintillation b) Interstellar scintillation c) Modeling and physical origin of the interplanetary and the interstellar plasma turbulence d) Scintillation as a tool for investigation of radio sources e) Seeing through interplanetary and interstellar turbulent media Ppt-presentations are available on the Web-site: http://www.prao.ru/conf/Colloquium/main.html

  12. Upconverting nanoparticles for optimizing scintillator based detection systems

    Science.gov (United States)

    Kross, Brian; McKisson, John E; McKisson, John; Weisenberger, Andrew; Xi, Wenze; Zom, Carl

    2013-09-17

    An upconverting device for a scintillation detection system is provided. The detection system comprises a scintillator material, a sensor, a light transmission path between the scintillator material and the sensor, and a plurality of upconverting nanoparticles particles positioned in the light transmission path.

  13. New liquid scintillators for fiber-optic applications

    International Nuclear Information System (INIS)

    Lutz, S.S.; Franks, L.A.; Flournoy, J.M.; Lyons, P.B.

    1981-01-01

    New long-wavelength-emitting, high-speed, liquid scintillators have been developed and tailored specifically for plasma diagnostic experiments employing fiber optics. These scintillators offer significant advantages over commercially available plastic scintillators in terms of sensitivity and bandwidth. FWHM response times as fast as 350 ps have been measured. Emission spectra, time response data, and relative sensitivity information are presented

  14. Development of new Polysiloxane Based Liquid Scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Dalla Palma, M.; Quaranta, A. [Department of Industrial Engineering, University of Trento,Via Sommarive, 9, 38123 Trento (Italy); INFN, Laboratori Nazionali di Legnaro,Viale dell' Universita, 2, 35020 Legnaro - Padova (Italy); Gramegna, F.; Marchi, T.; Cinausero, M. [INFN, Laboratori Nazionali di Legnaro,Viale dell' Universita, 2, 35020 Legnaro - Padova (Italy); Carturan, S.; Collazuol, G.; Checchia, C. [INFN, Laboratori Nazionali di Legnaro,Viale dell' Universita, 2, 35020 Legnaro - Padova (Italy); Department of Physics and Astronomy, University of Padova, Via Marzolo, 8, 35131 Padova (Italy); Degerlier, M. [Department of Physics, Nevsehir Haci Bektas Veli University, Science and Art Faculty, 50300 Nevsehir (Turkey)

    2015-07-01

    In the last decade, attention toward neutron detection has been growing in the scientific community, driven by new requirements in different fields of application ranging from homeland security to medical and material analysis, from research physics, to nuclear energy production. So far neutron detection, with particular attention to fast neutrons, has been mainly based on organic liquid scintillators, owing to their good efficiency and pulse shape discrimination (PSD) capability. Most of these liquids have however some main drawbacks given by toxicity, flammability, volatility and sensitivity to dissolved oxygen that limits the duration and the quality of their performances with worse handiness and increased costs. Phenyl-substituted polysiloxanes could address most of these issues, being characterized by low toxicity, low volatility and low flammability. Their optical properties can be tailored by changing the phenyl distribution and concentration thus allowing to increase the solubility of organic dyes, to modify the fluorescence spectra and to vary the refractive index of the medium. Furthermore, polysiloxanes have been recently exploited for the production of plastic scintillators with very good chemical and thermal stability and very good radiation hardness and the development of polysiloxane liquid scintillators could allow to combine these interesting properties with the supremacy of liquid scintillators as regarding PSD over plastics. For these reasons, the properties of several phenyl-substituted polysiloxane with different phenyl amounts and different viscosities have been investigated, with particular attention to the scintillation response and the pulse shape discrimination capability, and the results of the investigation are reported in this work. More in details, the scintillation light yield towards gamma rays ({sup 60}Co and {sup 137}Cs) of several polysiloxane liquids has been analyzed and compared with the light yield of a commercial non

  15. Set of counts by scintillations for atmospheric samplings; Ensemble de comptages par scintillations pour prelevements atmospheriques

    Energy Technology Data Exchange (ETDEWEB)

    Appriou, D.; Doury, A.

    1962-07-01

    The author reports the development of a scintillation-based counting assembly with the following characteristics: a photo-multiplier with a wide photo-cathode, a thin plastic scintillator for the counting of beta + alpha (and possibility of mounting an alpha scintillator), a relatively small own motion with respect to activities to be counted, a weakly varying efficiency. The authors discuss the counting objective, present equipment tests (counter, proportional amplifier and pre-amplifier, input drawer). They describe the apparatus operation, discuss the selection of scintillators, report the study of the own movement (electron-based background noise, total background noise, background noise reduction), discuss counts (influence of the external source, sensitivity to alpha radiations, counting homogeneity, minimum detectable activity) and efficiencies.

  16. Scintillating fiber detector performance, detector geometries, trigger, and electronics issues for scintillating fiber tracking

    International Nuclear Information System (INIS)

    Baumbaugh, A.E.

    1994-06-01

    Scintillating Fiber tracking technology has made great advances and has demonstrated great potential for high speed charged particle tracking and triggering. The small detector sizes and fast scintillation fluors available make them very promising for use at high luminosity experiments at today's and tomorrow's colliding and fixed target experiments where high rate capability is essential. This talk will discuss the current state of Scintillating fiber performance and current Visual Light Photon Counter (VLPC) characteristics. The primary topic will be some of the system design and integration issues which should be considered by anyone attempting to design a scintillating fiber tracking system which includes a high speed tracking trigger. Design. constraints placed upon the detector system by the electronics and mechanical sub-systems will be discussed. Seemingly simple and unrelated decisions can have far reaching effects on overall system performance. SDC and DO example system designs will be discussed

  17. General considerations for SSC scintillator calorimeters (For the scintillator general subgroup)

    International Nuclear Information System (INIS)

    Nodulman, L.

    1989-01-01

    The Scintillator Calorimetry group divided into three subgroups: a conventional uranium and plate design ala ZEUS, fiber design, and a group on general considerations. The considerations of the third group are reported here on geometrical and technical issues. 1 fig

  18. Scintillator device using a combined organic-inorganic scintillator as dose ratemeter

    International Nuclear Information System (INIS)

    Kolb, W.; Lauterbach, U.

    1974-01-01

    The dose ratemeter independent of energy in the energy region 17 keV to 3 MeV consists of an organic and an inorganic scintillator. The organic scintillation material of an anthracene monocrystal is surrounded by ZnS surface coating. The coating thickness of the inorganic scintillator ZnS is measured in such a manner for gamma and X-radiation below 100 keV that the light produced due to the incident radiation compensates for the decrease of light produced in the organic scintillator. The whole energy and dose rate region of interest for radiation protection can thus be measured with a detector volume of 135 cm 3 . (DG) [de

  19. System and method of liquid scintillation counting

    International Nuclear Information System (INIS)

    Rapkin, E.

    1977-01-01

    A method of liquid scintillation counting utilizing a combustion step to overcome quenching effects comprises novel features of automatic sequential introduction of samples into a combustion zone and automatic sequential collection and delivery of combustion products into a counting zone. 37 claims, 13 figures

  20. Waveshifting fiber readout of lanthanum halide scintillators

    International Nuclear Information System (INIS)

    Case, G.L.; Cherry, M.L.; Stacy, J.G.

    2006-01-01

    Newly developed high-light-yield inorganic scintillators coupled to waveshifting optical fibers provide the capability of efficient X-ray detection and millimeter scale position resolution suitable for high-energy cosmic ray instruments, hard X-ray/gamma ray astronomy telescopes and applications to national security. The CASTER design for NASA's proposed Black Hole Finder Probe mission, in particular, calls for a 6-8 m 2 hard X-ray coded aperture imaging telescope operating in the 20-600 keV energy band, putting significant constraints on cost and readout complexity. The development of new inorganic scintillator materials (e.g., cerium-doped LaBr 3 and LaCl 3 ) provides improved energy resolution and timing performance that is well suited to the requirements for national security and astrophysics applications. LaBr 3 or LaCl 3 detector arrays coupled with waveshifting fiber optic readout represent a significant advance in the performance capabilities of scintillator-based gamma cameras and provide the potential for a feasible approach to affordable, large area, extremely sensitive detectors. We describe some of the applications and present laboratory test results demonstrating the expected scintillator performance

  1. Semiconductor high-energy radiation scintillation detector

    International Nuclear Information System (INIS)

    Kastalsky, A.; Luryi, S.; Spivak, B.

    2006-01-01

    We propose a new scintillation-type detector in which high-energy radiation generates electron-hole pairs in a direct-gap semiconductor material that subsequently recombine producing infrared light to be registered by a photo-detector. The key issue is how to make the semiconductor essentially transparent to its own infrared light, so that photons generated deep inside the semiconductor could reach its surface without tangible attenuation. We discuss two ways to accomplish this, one based on doping the semiconductor with shallow impurities of one polarity type, preferably donors, the other by heterostructure bandgap engineering. The proposed semiconductor scintillator combines the best properties of currently existing radiation detectors and can be used for both simple radiation monitoring, like a Geiger counter, and for high-resolution spectrography of the high-energy radiation. An important advantage of the proposed detector is its fast response time, about 1 ns, essentially limited only by the recombination time of minority carriers. Notably, the fast response comes without any degradation in brightness. When the scintillator is implemented in a qualified semiconductor material (such as InP or GaAs), the photo-detector and associated circuits can be epitaxially integrated on the scintillator slab and the structure can be stacked-up to achieve virtually any desired absorption capability

  2. Neutron spectrometer using NE218 liquid scintillator

    International Nuclear Information System (INIS)

    Dance, J.B.; Francois, P.E.

    1976-01-01

    A neutron spectrometer has been constructed using NE218 liquid scintillator. Discrimination against electron-gamma events was obtained usng a charge-comparison pulse shape discrimination system. The resolution obtained was about 0.25 MeV F.W.H.M. at 2.0 MeV

  3. Scintillating fibre (SciFi) tracker

    CERN Multimedia

    Caraban Gonzalez, Noemi

    2017-01-01

    128 modules – containing 11 000 km of scintillating fibres – will make up the new SciFi tracker, which will replace the outer and inner trackers of the LHCb detector as part of the experiment’s major upgrade during Long Shutdown 2 (LS2)

  4. Neutron energy response measurement of scintillation detectors

    International Nuclear Information System (INIS)

    Yang Hongqiong; Peng Taiping; Yang Jianlun; Tang Zhengyuan; Yang Gaozhao; Li Linbo; Hu Mengchun; Wang Zhentong; Zhang Jianhua; Li Zhongbao; Wang Lizong

    2004-01-01

    Neutron sensitivities of detectors composed of plastic scintillator ST401, ST1422, ST1423 and phyotomultiplier tube in primary energy range of fission neutron are calibrated by direct current. The energy response curve of the detectors is obtained in this experiment. The experimental result has been compared with the theoretical calculation and they are in agreement within measuring uncertainty. (authors)

  5. Homogeneous scintillating LKr/Xe calorimeters

    International Nuclear Information System (INIS)

    Chen, M.; Mullins, M.; Pelly, D.; Shotkin, S.; Sumorok, K.; Akyuz, D.; Chen, E.; Gaudreau, M.P.J.; Bolozdynya, A.; Tchernyshev, V.; Goritchev, P.; Khovansky, V.; Koutchenkov, A.; Kovalenko, A.; Lebedenko, V.; Vinogradov, V.; Gusev, L.; Sheinkman, V.; Krasnokutsky, R.N.; Shuvalov, R.S.; Fedyakin, N.N.; Sushkov, V.; Akopyan, M.; Doke, T.; Kikuchi, J.; Hitachi, A.; Kashiwagi, T.; Masuda, K.; Shibamura, E.; Ishida, N.; Sugimoto, S.

    1993-01-01

    Recent R and D work on full length scintillating homogeneous liquid xenon/krypton (LXe/Kr) cells has established the essential properties for precision EM calorimeters: In-situ calibration using α's, radiation hardness as well as the uniformity required for δE/E≅0.5% for e/γ's above 50 GeV. (orig.)

  6. Fluorescent compounds for plastic scintillation applications

    International Nuclear Information System (INIS)

    Pla-Dalmau, A.; Bross, A.D.

    1994-04-01

    Several 2-(2'-hydroxyphenyl)benzothiazole, -benzoxazole, and -benzimidazole derivatives have been prepared. Transmittance, fluorescence, light yield, and decay time characteristics of these compounds have been studied in a polystyrene matrix and evaluated for use in plastic scintillation detectors. Radiation damage studies utilizing a 60 C source have also been performed

  7. The Scintillator Tile Hadronic Calorimeter Prototype

    International Nuclear Information System (INIS)

    Rusinov, V.

    2006-01-01

    A high granularity scintillator hadronic calorimeter prototype is described. The calorimeter is based on a novel photodetector - Silicon Photo-Multiplier (SiPM). The main parameters of SiPM are discussed as well as readout cell construction and optimization. The experience with a small prototype production and testing is described. A new 8 k channel prototype is being manufactured now

  8. Light pulse shapes from plastic scintillators

    International Nuclear Information System (INIS)

    Moszynski, M.; Bengtson, B.

    1977-01-01

    A detailed study of the light pulse shape from the binary NE 111 and the ternary Pilot U, Naton 136, KL 236, NE 102A, NE 104 and NE 110 plastic scintillators was performed by the single photon method using XP 1021 and C 31024 photomultipliers. The analysis of the shape of the light pulses determined experimentally for several samples of different dimensions gave the following conclusions. The original light pulse shape from the binary NE 111 scintillator, as measured with a 5 mm thick polished sample is described analytically by the convolution integral of a Gaussian and an exponential function. The Gaussian function may reflect a deexcitation of several higher levels of the solvent molecules excited by nuclear particles preceding an intermolecular energy transfer in the scintillator. It may introduce a rather important limitation of the speed of plastic scintillators as the standard deviation of the Gaussian function is equal to 0.2 ns. The light pulse shape from the ternary plastics is described by the convolution integral of a Gaussian and two exponential functions. The Gaussian function presents the rate of energy transfer from nuclear particles to the primary solute as in the binary plastics. The exponential functions describe the energy transfer from the primary solute to the wavelength shifter and the final emission of the light. (Auth.)

  9. Liquid scintillation counting (LSC) - an overview

    International Nuclear Information System (INIS)

    Ravi, S.; Mathew, K.M.

    2005-01-01

    In Liquid Scintillation Counting, the amount of light produced is proportional to the amount of radiation present in the sample and the energy of the light produced is proportional to the energy of the radiation that is present in the sample. This makes LSC a very convenient tool to measure radioactivity

  10. Radioactive flow detectors: liquid or solid scintillators

    International Nuclear Information System (INIS)

    Reich, A.R.

    1983-01-01

    During the past five years, two schools of thought have emerged producing two different types of radio-HPLC detectors. Based on the naphthalene-in-the-vial principle, manufacturers have developed heterogeneous scintillation detectors. In these detectors the anthracene or naphthalene crystals are replaced by other scintillators. In order to avoid dead space and turbulence, a narrow diameter tube is used, either straight, or more popularly formed into a coil or a 'U' as the cell. To optimize light transmission to the photomultiplier tubes, mirrors are used. Due to limiting factors in this technique the counting efficiency for tritium is below the 10 percent level. The other school of radio-HPLC detectors based their design on classical liquid scintillation counting technology. In a homogeneous detector, the effluent from the HPLC system is mixed with a suitable liquid scintillator before entering the counting cell. The cell design is typically a flat glass or Teflon coil tightly sandwiched between two photomultiplier tubes, making good optical contact without the use of mirrors. Depending on the chromatographic effluent, 3 H efficiencies between 25 to 50 percent, and 14 C counting efficiencies up to 85 percent can be achieved

  11. Scintillation camera for high activity sources

    International Nuclear Information System (INIS)

    Arseneau, R.E.

    1976-01-01

    A scintillation camera is provided with electrical components which expand the intrinsic maximum rate of acceptance for processing of pulses emanating from detected radioactive events. Buffer storage is provided to accommodate temporary increases in the level of radioactivity. An early provisional determination of acceptability of pulses allows many unacceptable pulses to be discarded at an early stage

  12. Luminescence and energy transfer in Garnet Scintillators

    NARCIS (Netherlands)

    Ogiegło, J.M.

    2012-01-01

    The thesis is focused on development and fundamental understanding of scintillators that play a central role in the field of medical imaging. These materials convert high energy, gamma or X-ray, radiation into visible light that is then used to create a detailed image of the patient’s body. The

  13. Basic processes and scintillator and semiconductor detectors

    International Nuclear Information System (INIS)

    Bourgeois, C.

    1994-01-01

    In the following course, the interaction of heavy charged particles, electrons and Γ with matter is represented. Two types of detectors are studied, organic and inorganic scintillators and semiconductors. The signal formation is analysed. (author). 13 refs., 48 figs., 5 tabs

  14. A mobile antineutrino detector with plastic scintillators

    International Nuclear Information System (INIS)

    Kuroda, Y.; Oguri, S.; Kato, Y.; Nakata, R.; Inoue, Y.; Ito, C.; Minowa, M.

    2012-01-01

    We propose a new type segmented antineutrino detector made of plastic scintillators for the nuclear safeguard application. A small prototype was built and tested to measure background events. A satisfactory unmanned field operation of the detector system was demonstrated. Besides, a detailed Monte Carlo simulation code was developed to estimate the antineutrino detection efficiency of the detector.

  15. Determining random counts in liquid scintillation counting

    International Nuclear Information System (INIS)

    Horrocks, D.L.

    1979-01-01

    During measurements involving coincidence counting techniques, errors can arise due to the detection of chance or random coincidences in the multiple detectors used. A method and the electronic circuits necessary are here described for eliminating this source of error in liquid scintillation detectors used in coincidence counting. (UK)

  16. Thallium bromide photodetectors for scintillation detection

    CERN Document Server

    Hitomi, K; Shoji, T; Hiratate, Y; Ishibashi, H; Ishii, M

    2000-01-01

    A wide bandgap compound semiconductor, TlBr, has been investigated as a blue sensitive photodetector material for scintillation detection. The TlBr photodetectors have been fabricated from the TlBr crystals grown by the TMZ method using materials purified by many pass zone refining. The performance of the photodetectors has been evaluated by measuring their leakage current, quantum efficiency, spatial uniformity, direct X-ray detection and scintillation detection characteristics. The photodetectors have shown high quantum efficiency for the blue wavelength region and high spatial uniformity for their optical response. In addition, good direct X-ray detection characteristics with an energy resolution of 4.5 keV FWHM for 22 keV X-rays from a sup 1 sup 0 sup 9 Cd radioactive source have been obtained. Detection of blue scintillation from GSO and LSO scintillators irradiated with a sup 2 sup 2 Na radioactive source has been done successfully by using the photodetectors at room temperature. A clear full-energy pea...

  17. Testing of the scintillation sandwich prototype

    International Nuclear Information System (INIS)

    Vashkevich, V.

    1995-06-01

    The 3 m 2 prototype of the surface detector using optical fiber readout was completely prepared for testing measurements in February 1995 at Fermilab. Two 25 mm thick, 3 m 2 acrylic scintillation plates (1.2 x 2.5 m 2 ) are used for light collection in the upper (above the 25 mm steel plate) and lower (below the steel) counters of the sandwich. The light is collected with the help of 1 mm diameter wavelength shifter fiber loops 3 m long inserted in the grooves on the top surface of the scintillator, 3 fibers per groove. We used Kurary Y11, 200 ppm of shifter dye, and double clad fibers. 1.5 m of clear fibers spliced to each end of the shifter fiber transport the light to the phototube. Spacing between the grooves is 5 cm. The counter's edges were painted with BICRON (BC620) white reflective paint. The scintillation plates were wrapped with Dupont Tyvek. The glued bundle of fibers is connected to an EMI-9902KB 38 mm phototube through the simple light mixer bar. Used PM has a ''green extended'' rubidium bialkali photocathode. The report contains information on the testing of the scintillation sandwich

  18. Sample oxidation for liquid scintillation counting

    International Nuclear Information System (INIS)

    Kisieleski, W.E.; Buess, E.M.

    1976-01-01

    The general features of biological and medical investigations which are responsible for the demands such investigations place upon the design specifications of liquid scintillation counters and associated methodology are reviewed. Special emphasis is given to the oxidative technique for sample preparation

  19. A projective geometry lead fiber scintillator detector

    International Nuclear Information System (INIS)

    Paar, H.; Thomas, D.; Sivertz, M.; Ong, B.; Acosta, D.; Taylor, T.; Shreiner, B.

    1990-01-01

    The Superconducting Super Collider (SSC), presently under construction near Dallas, Texas requires highly sophisticated particle detectors. The energy and particle flux at the SSC are more than an order of magnitude higher than the highest machine located at the Fermi National Accelerator near Chicago. An important element of particle detectors for the SSC is the calorimeter. It measures a particle's energy by sampling its energy deposit in heavy material, such as (depleted) uranium or lead. The sampling medium must be interspersed with heavy absorber material. In the case of scintillating plastic, two methods are under consideration: plates and fibers. In the case of plates, a sandwich of scintillator plates and uranium plates is constructed. In the use of fibers (still in the prototype stage), 1 mm. diameter cylindrical scintillating fibers are inserted into grooves that are machined into lead layers. The layers are stacked and epoxied together to form the required geometrical shape of the detector. Lead and scintillating plastic sampling can meet the physics requirements of the detector. This has been shown in an R ampersand D program which is underway at the University of California at San Diego (UCSD), High Energy Physics Group. This R ampersand D is funded by the Department of Energy, High Energy Physics and SSC Divisions

  20. Experimental evidence of infrared scintillation in crystals

    CERN Document Server

    Belogurov, S; Carugno, Giovanni; Conti, E; Iannuzzi, D; Meneguzzo, Anna Teresa

    2000-01-01

    We present experimental results on infrared emission induced by protons in some solid-state samples. Infrared scintillation occurs in many crystals, with different yield values and time-response behaviours. A rough measurement of the emission wavelength of CsI(Tl) is also reported.

  1. Perspectives on the future development of new scintillators

    International Nuclear Information System (INIS)

    Melcher, C.L.

    2005-01-01

    The search for new scintillators has become increasingly sophisticated and increasingly successful in recent years, driven to a large degree by the rapidly growing needs of medical imaging and high energy physics. Better understanding of the various scintillation mechanisms has led to innovative new materials for both gamma-ray and neutron detection, and the concept of scintillator design and engineering has emerged, whereby materials are optimized according to the scintillation properties needed by specific applications. Numerous promising candidates have been identified during the last few years, and several are currently being actively developed for commercial production. Economical crystal growth often represents a significant challenge in the practical application of new scintillation materials

  2. A new inorganic-organic nanohybrid based on a copper(II) semicarbazone complex and the PMo.sub.12./sub.O.sup.3-./sup..sub.40./sub. polyanion: synthesis, characterization, crystal structure and photocatalytic activity for degradation of cationic dyes

    Czech Academy of Sciences Publication Activity Database

    Farhadi, S.; Mahmoudi, F.; Dušek, Michal; Eigner, Václav; Kučeráková, Monika

    2017-01-01

    Roč. 122, Jan (2017), s. 247-256 ISSN 0277-5387 R&D Projects: GA ČR(CZ) GA14-03276S; GA MŠk LO1603 EU Projects: European Commission(XE) CZ.2.16/3.1.00/24510 Institutional support: RVO:68378271 Keywords : inorganic-organic hybrid * semicarbazone complex * nanohybrid * photodegradation * cationic dyes Subject RIV: CA - Inorganic Chemistry OBOR OECD: Inorganic and nuclear chemistry Impact factor: 1.926, year: 2016

  3. Analysis of feed stream acid gas concentration effects on the transport properties and separation performance of polymeric membranes for natural gas sweetening: A comparison between a glassy and rubbery polymer

    KAUST Repository

    Vaughn, Justin T.

    2014-09-01

    A 6FDA based polyamide-imide, 6F-PAI-1, is compared to Pebax®, a commercially available rubbery polyether/polyamide block copolymer, for the simultaneous separation of CO2 and H2S from CH4. Feed streams of 20/20/60 and 5/45/50H2S/CO2/CH4 were used to compare the effect of acid gas concentration on the separation efficiency of 6F-PAI-1 and Pebax® under industrially relevant conditions. 6F-PAI-1 showed CO2/CH4 selectivities at 850psia total feed pressure of 30 and 40 for the 20/20/60 and 5/45/50 feed streams, respectively, while selectivity for H2S/CH4 was approximately 20 for both feeds. Pebax® showed selectivities of 40 and 10 for H2S/CH4 and CO2/CH4, respectively. Both selectivities were mostly independent of acid gas concentration in the feed, an unsurprising trend considering the non-glassy nature of this material. The selectivities in 6F-PAI-1 translated to less than 6% CH4 lost in the permeate stream for both feeds, while for the 5/45/50 feed, CH4 fraction in the permeate at 850psia was less than 4%. These promising results suggest that glassy polymers possessing favorable intrinsic plasticization resistance, such as 6F-PAI-1, may be appropriate for the typical case of natural gas sweetening where CO2 concentration in the feed is higher than it is for H2S. © 2014 Elsevier B.V.

  4. Eu-activated fluorochlorozirconate glass-ceramic scintillators

    International Nuclear Information System (INIS)

    Johnson, J. A.; Schweizer, S.; Henke, B.; Chen, G.; Woodford, J.; Newman, P. J.; MacFarlane, D. R.

    2006-01-01

    Rare-earth-doped fluorochlorozirconate (FCZ) glass-ceramic materials have been developed as scintillators and their properties investigated as a function of dopant level. The paper presents the relative scintillation efficiency in comparison to single-crystal cadmium tungstate, the scintillation intensity as a function of x-ray intensity and x-ray energy, and the spatial resolution (modulation transfer function). Images obtained with the FCZ glass-ceramic scintillator and with cadmium tungstate are also presented. Comparison shows that the image quality obtained using the glass ceramic is close to that from cadmium tungstate. Therefore, the glass-ceramic scintillator could be used as an alternative material for image formation resulting from scintillation. Other inorganic scintillators such as single crystals or polycrystalline films have limitations in resolution or size, but the transparent glass-ceramic can be scaled to any shape or size with excellent resolution

  5. Comparison of multifrequency equatorial scintillation - American and Pacific sectors

    Science.gov (United States)

    Livingston, R. C.

    1980-08-01

    In this paper we examine the severity of radio wave amplitude scintillation measured at two stations near the equator but far separated in longitude: Kwajelein, Marshall Islands (167 E), and Ancon, Peru (-77 E). The data used are long-term observations of the Defense Nuclear Agency (DNA) Wideband satellite signal intensity at VHF, UHF, and L band frequencies. The seasonal behavior of the scintillation at the two stations is similar; each shows a broad 8- to 9-month disturbed season centered about local summer. There is short-term variability in the scintillation occurrence statistics but no clear equinoctial maxima. Little difference is observed in the occurrence or severity of L band scintillation at the two stations, although a systematic difference in the frequency dependence of the scintillation produces significantly stronger VHF and UHF scintillation at Ancon. The VHF and UHF latitudinal distributions of scintillation are asymmetric about the geomagnetic equator at both stations.

  6. Electron traps and scintillation mechanism in YAlO3:Ce and LuAlO3:Ce scintillators

    International Nuclear Information System (INIS)

    Wojtowicz, A.J.; Glodo, J.; Drozdowski, W.; Przegietka, K.R.

    1998-01-01

    In this paper we present the results of thermoluminescence, isothermal decay and scintillation light yield measurements on two isostructural scintillator materials, YAlO 3 :Ce and LuAlO 3 :Ce. In addition to the variety of deep traps identified by thermoluminescence and isothermal decays, scintillation light yield experiments demonstrate the presence in both materials of a number of relatively shallow traps. While the deep traps may reduce the scintillation light yield, they do not influence the kinetics of the process. The shallow traps, on the other hand, by interfering with the process of radiative recombination of charge carriers via Ce 3+ ions, can strongly affect not only the yield of the scintillation process but its kinetics as well. The presence of shallow traps provides a consistent explanation for a number of poorly understood relationships between the two scintillator materials, including a higher room temperature scintillation light yield and longer scintillation decay time in YAlO 3 :Ce, and a longer scintillation rise time in LuAlO 3 :Ce. Theoretical analysis indicates that elimination of these traps would make the two materials nearly identical in scintillator performance. Although the specific identity of all traps remains elusive, the performance of both scintillator materials is now, in practical terms, fully understood. (Copyright (c) 1998 Elsevier Science B.V., Amsterdam. All rights reserved.)

  7. Calculations and measurements of the scintillator-to-water stopping power ratio of liquid scintillators for use in proton radiotherapy

    International Nuclear Information System (INIS)

    Scott Ingram, W.; Robertson, Daniel; Beddar, Sam

    2015-01-01

    Liquid scintillators are a promising detector for high-resolution three-dimensional proton therapy dosimetry. Because the scintillator comprises both the active volume of the detector and the phantom material, an ideal scintillator will exhibit water equivalence in its radiological properties. One of the most fundamental of these is the scintillator’s stopping power. The objective of this study was to compare calculations and measurements of scintillator-to-water stopping power ratios to evaluate the suitability of the liquid scintillators BC-531 and OptiPhase HiSafe 3 for proton dosimetry. We also measured the relative scintillation output of the two scintillators. Both calculations and measurements show that the linear stopping power of OptiPhase is significantly closer to water than that of BC-531. BC-531 has a somewhat higher scintillation output. OptiPhase can be mixed with water at high concentrations, which further improves its scintillator-to-water stopping power ratio. However, this causes the solution to become cloudy, which has a negative impact on the scintillation output and spatial resolution of the detector. OptiPhase is preferred over BC-531 for proton dosimetry because its density and scintillator-to-water stopping power ratio are more water equivalent

  8. Background characterization in a liquid scintillation spectrometer

    International Nuclear Information System (INIS)

    Rodriguez Barquero, L.; Los Arcos, J.M.; Jimenez de Mingo, A.

    1995-01-01

    An alternate procedure for background count rate estimation in a liquid scintillation spectrometer is presented, which does not require to measure a blank with similar composition, volume and quench, to the problem sample. The procedure is based on a double linear parameterization which was obtained from a systematic study of the background observed with glass vials, in three different windows, 0 - 20 KeV, 0 - 800 KeV and 0 - 2 MeV, for volume between 2 and 20 mi of three commercial scintillators, Hisafe II, Ultima-Gold and Instagel, and quenching degree in the interval equivalent to 50% - 3% tritium efficiency. This procedure was tested with standard samples of 3H, and led to average discrepancies less than 10% for activity ≥0,6 Bq, against conventional methods for which the discrepancies are twice on average. (Author) 10 refs

  9. Background characterization in a liquid scintillation spectrometer

    International Nuclear Information System (INIS)

    Rodriguez Barquero, L.; Los arcos, J.M.; Jimenez de Mingo, A.

    1995-01-01

    An alternate procedure for background count rate estimation in a liquid scintillation spectrometer is presented, which does not require to measure a blank with similar composition, volume and quench, to the problem sample. The procedure is based on a double linear parameterization which was obtained from a systematic study of the background observed with glass vials, in three different windows, 0-20 KeV, 0-800 KeV and 0-2 MeV, for volume between 2 and 20 ml of three commercial scintillators, Hisafe II, Ultima-gold and Instagel, and quenching degree in the interval equivalent to 50%-3% tritium efficiency. This procedure was tested with standard samples of ''3 H, and led to average discrepancies less than 10% for activity => 0,6 Bq, against conventional methods for which the discrepancies are twice on average

  10. Development of High-Resolution Scintillator Systems

    International Nuclear Information System (INIS)

    Larry A. Franks; Warnick J. Kernan

    2007-01-01

    Mercuric iodide (HgI2) is a well known material for the direct detection of gamma-rays; however, the largest volume achievable is limited by the thickness of the detector which needs to be a small fraction of the average trapping length for electrons. We report results of using HgI2 crystals to fabricate photocells used in the readout of scintillators. The optical spectral response and efficiency of these photocells were measured and will be reported. Nuclear response from an HgI2 photocell that was optically matched to a cerium-activated scintillator is presented and discussed. Further improvements can be expected by optimizing the transparent contact technology

  11. Plastic fiber scintillator response to fast neutrons

    Energy Technology Data Exchange (ETDEWEB)

    Danly, C. R.; Sjue, S.; Wilde, C. H.; Merrill, F. E.; Haight, R. C. [Los Alamos National Laboratory, Los Alamos, New Mexico 87544 (United States)

    2014-11-15

    The Neutron Imaging System at NIF uses an array of plastic scintillator fibers in conjunction with a time-gated imaging system to form an image of the neutron emission from the imploded capsule. By gating on neutrons that have scattered from the 14.1 MeV DT energy to lower energy ranges, an image of the dense, cold fuel around the hotspot is also obtained. An unmoderated spallation neutron beamline at the Weapons Neutron Research facility at Los Alamos was used in conjunction with a time-gated imaging system to measure the yield of a scintillating fiber array over several energy bands ranging from 1 to 15 MeV. The results and comparison to simulation are presented.

  12. Multifrequency techniques for studying interplanetary scintillations

    International Nuclear Information System (INIS)

    Woo, R.

    1975-01-01

    Rytov's approximation or the method of smooth perturbations is utilized to derive the temporal frequency spectra of the amplitude and phase fluctuations of multifrequency plane and spherical waves propagating in the interplanetary medium and solar corona. It is shown that multifrequency observations of interplanetary scintillations using either compact radio stars or spacecraft radio signals are desirable because the correlation of the multifrequency waves yields additional independent measurements of the solar wind and turbulence. Measurements of phase fluctuations are also desirable because, unlike amplitude fluctuations, they provide information on the full range of scale sizes for the electron density fluctuations. It is shown that a coherent dual-frequency radio system is particularly useful in making such measurements. In addition to providing a means for interpreting observations of multifrequency interplanetary scintillations, the analysis is also essential for estimating the effects of solar corona turbulence on the communications and navigation of a spacecraft whose line-of-sight path passes close to the Sun

  13. Scintillation detectors of Alborz-I experiment

    International Nuclear Information System (INIS)

    Pezeshkian, Yousef; Bahmanabadi, Mahmud; Abbasian Motlagh, Mehdi; Rezaie, Masume

    2015-01-01

    A new air shower experiment of the Alborz Observatory, Alborz-I, located at the Sharif University of Technology, Iran, will be constructed in near future. An area of about 30×40 m 2 will be covered by 20 plastic scintillation detectors (each with an area of 50×50 cm 2 ). A series of experiments have been performed to optimize the height of light enclosures of the detectors for this array and the results have been compared to an extended code simulation of these detectors. Operational parameters of the detector obtained by this code are cross checked by the Geant4 simulation. There is a good agreement between the extended-code and Geant4 simulations. We also present further discussions on the detector characteristics, which can be applicable for all scintillation detectors with a similar configuration

  14. Liquid scintillation alpha particle spectrometry. Progress report

    International Nuclear Information System (INIS)

    Bell, L.L.; Hakooz, S.A.; Johnson, L.O.; Nieschmidt, E.B.; Meikrantz, D.H.

    1979-12-01

    Objective to develop a technique whereby Pu may be put into solution, extracted by solvent extraction into a suitable extractive scintillant and subsequently counted. Presented here are results of attempts to separate beta and alpha activities through pulse shape discrimination. A qualitative discussion is given which yields alpha particle peak widths, resolution and response. The detection efficiency for alpha particles in a liquid scintillant is 100%. Present detection sensitivities of the equipment being used are: 4.5 x 10 -6 μCi (100 s), 1.2 x 10 -6 μCi (1000 s), and 4.0 x 10 -7 μCi (10,000 s) at the 3 sigma level. The detectability of a particular alpha-emitting species is strongly dependent upon the population of other species. The ability to discriminate depends upon the system resolution. 14 figures, 2 tables

  15. Central Tracking Detector Based on Scintillating Fibres

    CERN Multimedia

    2002-01-01

    Scintillating fibres form a reasonable compromise for central tracking detectors in terms of price, resolution, response time, occupancy and heat production. \\\\ \\\\ New fluorescents with large Stokes shifts have been produced, capable of working without wavelength shifters. Coherent multibundles have been developed to achieve high packing fractions. Small segments of tracker shell have been assembled and beam tests have confirmed expectations on spatial resolution. An opto-electronic delay line has been designed to delay the track patterns and enable coincidences with a first level trigger. Replacement of the conventional phosphor screen anode with a Si pixel chip is achieved. This tube is called ISPA-tube and has already been operated in beam tests with a scintillating fibres tracker. \\\\ \\\\ The aim of the proposal is to improve hit densities for small diameter fibres by increasing the fraction of trapped light, by reducing absorption and reflection losses, by reflecting light at the free fibre end, and by inc...

  16. Low level scintillation counting of 239Pu

    International Nuclear Information System (INIS)

    Fueloep, M.; Minarik, F.; Cierna, V.

    1984-01-01

    For measuring the content of 239 Pu in samples taken from the working or living environment, methods should be used which are sufficiently sensitive for determining activities of the order of 10 -3 Bq. It is useful to use liquid scintillators for reasons of their 4π geometry and the exclusion of kinetic energy losses of particles detected in the sample and on the path between the sample and the detector. The method of background discrimination according to pulse shape may be used to suppress gamma background in the area of alpha particle peaks to the level 2.5x10 -4 s -1 . The diagram is given of electronic circuits for shape discrimination. The scintillator used was a SLS-31 with a PBD activator, a POPOP spectrum shifter and a mixture of solvents: toluene, dioxane and methanol. The efficiency of 239 Pu alpha particle detection is estimated at 78% and may further be improved by improving shape discrimination. (M.D.)

  17. Scintillating Optical Fiber Imagers for biology

    International Nuclear Information System (INIS)

    Mastrippolito, R.

    1990-01-01

    S.O.F.I (Scintillating Optical Fiber Imager) is a detector developed to replace the autoradiographic films used in molecular biology for the location of radiolabelled ( 32 P) DNA molecules in blotting experiments. It analyses samples on a 25 x 25 cm 2 square area still 25 times faster than autoradiographic films, with a 1.75 and 3 mm resolution for two orthogonal directions. This device performs numerised images with a dynamic upper than 100 which allows the direct quantitation of the analysed samples. First, this thesis describes the S.O.F.I. development (Scintillating Optical Fibers, coding of these fibers and specific electronic for the treatment of the Multi-Anode Photo-Multiplier signals) and experiments made in collaboration with molecular biology laboratories. In a second place, we prove the feasibility of an automatic DNA sequencer issued from S.O.F.I [fr

  18. Plastic scintillator detector for pulsed flux measurements

    Science.gov (United States)

    Kadilin, V. V.; Kaplun, A. A.; Taraskin, A. A.

    2017-01-01

    A neutron detector, providing charged particle detection capability, has been designed. The main purpose of the detector is to measure pulsed fluxes of both charged particles and neutrons during scientific experiments. The detector consists of commonly used neutron-sensitive ZnS(Ag) / 6LiF scintillator screens wrapping a layer of polystyrene based scintillator (BC-454, EJ-254 or equivalent boron loaded plastic). This type of detector design is able to log a spatial distribution of events and may be scaled to any size. Different variations of the design were considered and modelled in specialized toolkits. The article presents a review of the detector design features as well as simulation results.

  19. Plastic scintillator detector for pulsed flux measurements

    International Nuclear Information System (INIS)

    Kadilin, V V; Kaplun, A A; Taraskin, A A

    2017-01-01

    A neutron detector, providing charged particle detection capability, has been designed. The main purpose of the detector is to measure pulsed fluxes of both charged particles and neutrons during scientific experiments. The detector consists of commonly used neutron-sensitive ZnS(Ag) / 6 LiF scintillator screens wrapping a layer of polystyrene based scintillator (BC-454, EJ-254 or equivalent boron loaded plastic). This type of detector design is able to log a spatial distribution of events and may be scaled to any size. Different variations of the design were considered and modelled in specialized toolkits. The article presents a review of the detector design features as well as simulation results. (paper)

  20. Calibration of the neutron scintillation counter threshold

    International Nuclear Information System (INIS)

    Noga, V.I.; Ranyuk, Yu.N.; Telegin, Yu.N.

    1978-01-01

    A method for calibrating the threshold of a neutron counter in the form of a 10x10x40 cm plastic scintillator is described. The method is based on the evaluation of the Compton boundary of γ-spectrum from the discrimination curve of counter loading. The results of calibration using 60 Co and 24 Na γ-sources are given. In order to eValuate the Compton edge rapidly, linear extrapolation of the linear part of the discrimination curve towards its intersection with the X axis is recommended. Special measurements have shown that the calibration results do not practically depend on the distance between the cathode of a photomultiplier and the place where collimated γ-radiation of the calibration source reaches the scintillator

  1. Transparent Ceramic Scintillator Fabrication, Properties and Applications

    International Nuclear Information System (INIS)

    Cherepy, N.J.; Kuntz, J.D.; Roberts, J.J.; Hurst, T.A.; Drury, O.B.; Sanner, R.D.; Tillotson, T.M.; Payne, S.A.

    2008-01-01

    Transparent ceramics offer an alternative to single crystals for scintillator applications such as gamma ray spectroscopy and radiography. We have developed a versatile, scaleable fabrication method, using Flame Spray Pyrolysis (FSP) to produce feedstock which is readily converted into phase-pure transparent ceramics. We measure integral light yields in excess of 80,000 Ph/MeV with Cerium-doped Garnets, and excellent optical quality. Avalanche photodiode readout of Garnets provides resolution near 6%. For radiography applications, Lutetium Oxide offers a high performance metric and is formable by ceramics processing. Scatter in transparent ceramics due to secondary phases is the principal limitation to optical quality, and afterglow issues that affect the scintillation performance are presently being addressed

  2. Scintillation {gamma} spectrography. Physical principles. Apparatus. Operation; Spectrographie {gamma} a scintillations. Principes physiques. Appareillage. Utilisation

    Energy Technology Data Exchange (ETDEWEB)

    Julliot, C [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    The scintillation detector forms the main part of the instrument used, the electronic unit presenting the results produced. After a brief description of the process of {gamma} photon absorption in the material, the particular case of NaI (T1), the scintillator used, is examined. The intensity of the scintillation caused by {gamma} ray absorption and the characteristics of the photomultiplier play a determining part in the energy resolution of the instrument. For the {gamma} recording spectrograph, we show to what extent the technique for using the electronic unit can modify the results. A detailed description is given of the activity measurement of a {gamma}-emitting radioelement by the spectrographic method. (author) [French] Dans l'appareillage utilise, le detecteur a scintillations constitue la piece maitresse, l'ensemble electronique presente les resultats issus du detecteur. Apres avoir brievement decrit le processus d'absorption des photons {gamma} dans la matiere, nous examinons le cas particulier du NaI(T1), le scintillateur utilise. L'intensite de la scintillation provoque par l'absorption des rayons {gamma} et les caracteristiques du photomultiplicateur jouent un role determinant dans la resolution en energie de l'appareil. Pour le spectrographe {gamma} enregistreur, nous indiquons dans quelle mesure la technique d'utilisation de l'ensemble electronique peut modifier les resultats. La-mesure de l'activite d'un radioelement emetteur {gamma} par spectrographie fait l'objet d'une description detaillee. (auteur)

  3. Dual-readout calorimetry with scintillating crystals

    International Nuclear Information System (INIS)

    Pinci, D

    2009-01-01

    The dual-readout approach, which allows an event-by-event measurement of the electromagnetic shower fraction, was originally demonstrated with the DREAM sampling calorimeter. This approach can be extended to homogeneous detectors like crystals if Cherenkov and scintillation light can be separated. In this paper we present several methods we developed for distinguishing the two components in PWO and BGO based calorimeters and the results obtained.

  4. Scintillation detectors in experiments on plasma accelerators

    International Nuclear Information System (INIS)

    Bystritskij, V.M.; Gerasimov, V.V.; Kublikov, R.V.; Parzhitskij, S.S.; Smirnov, V.S.; Wozniak, J.; Dudkin, G.N.; Nechaev, B.A.; Padalko, V.M.

    2005-01-01

    The gating circuits for photomultipliers of scintillation detectors operating in powerful pulsed electromagnetic and nuclear radiation fields are investigated. PMTs with the jalousie-type dynode system and with the linear dynode system are considered. The basic gating circuits of the photomultipliers involving active and resistor high-voltage dividers are given. The results of the investigations are important for experiments in which it is necessary to discriminate in time the preceding background radiation and the process of interest. (author)

  5. Improved Neutron Scintillators Based on Nanomaterials

    International Nuclear Information System (INIS)

    Friesel, Dennis

    2008-01-01

    The development work conducted in this SBIR has so far not supported the premise that using nano-particles in LiFZnS:Ag foils improves their transparency to 420 (or other frequency) light. This conclusion is based solely on the light absorption properties of LiFZnS foils fabricated from nano- and from micro-particles. Furthermore, even for the case of the Gd 2 O 3 foils, the transmission of 420 nm light gained by using nano-particles all but disappears as the foil thickness is increased beyond about 0.2 mm, a practical scintillator thickness. This was not immediately apparent from the preliminary study since no foils thicker than about 0.04 mm were produced. Initially it was believed that the failure to see an improvement by using nano-particles for the LiFZnS foils was caused by the clumping of the particles in Toluene due to the polarity of the ZnS particles. However, we found, much to our surprise, that nano-particle ZnS alone in polystyrene, and in Epoxy, had worse light transmission properties than the micro-particle foils for equivalent thickness and density foils. The neutron detection measurements, while disappointing, are attributable to our inability to procure or fabricate Bulk Doped ZnS nanoparticles. The cause for the failure of nano-particles to improve the scintillation light, and hence improved neutron detection efficiency, is a fundamental one of light scattering within the scintillator. A consequence of PartTec's documentation of this is that several concepts for the fabrication of improved 6 LiFZnS scintillators were formulated that will be the subject of a future SBIR submission.

  6. Homogeneous scintillating LKr/Xe calorimeters

    Energy Technology Data Exchange (ETDEWEB)

    Chen, M.; Mullins, M.; Pelly, D.; Shotkin, S.; Sumorok, K. (Lab. for Nuclear Science, MIT, Cambridge, MA (United States)); Akyuz, D.; Chen, E.; Gaudreau, M.P.J. (Plasma Fusion Center, MIT, Cambridge, MA (United States)); Bolozdynya, A.; Tchernyshev, V.; Goritchev, P.; Khovansky, V.; Koutchenkov, A.; Kovalenko, A.; Lebedenko, V.; Vinogradov, V.; Gusev, L.; Sheinkman, V. (ITEP, Moscow (Russia)); Krasnokutsky, R.N.; Shuvalov, R.S.; Fedyakin, N.N.; Sushkov, V. (IHEP, Serpukhov (Russia)); Akopyan, M. (Inst. for Nuclear Research, Moscow (Russia)); Doke, T.; Kikuchi, J.; Hitachi, A.; Kashiwagi, T. (Science and Eng. Res. Lab., Waseda Univ., Tokyo (Japan)); Masuda, K.; Shibamura, E. (Saitama Coll. of Health (Japan)); Ishida, N. (Seikei Univ. (Japan)); Sugimoto, S. (INS, Univ. Tokyo (Japan))

    1993-03-20

    Recent R and D work on full length scintillating homogeneous liquid xenon/krypton (LXe/Kr) cells has established the essential properties for precision EM calorimeters: In-situ calibration using [alpha]'s, radiation hardness as well as the uniformity required for [delta]E/E[approx equal]0.5% for e/[gamma]'s above 50 GeV. (orig.).

  7. Interaction probability value calculi for some scintillators

    International Nuclear Information System (INIS)

    Garcia-Torano Martinez, E.; Grau Malonda, A.

    1989-01-01

    Interaction probabilities for 17 gamma-ray energies between 1 and 1.000 KeV have been computed and tabulated. The tables may be applied to the case of cylindrical vials with radius 1,25 cm and volumes 5, 10 and 15 ml. Toluene, Toluene/Alcohol, Dioxane-Naftalen, PCS, INSTAGEL and HISAFE II scintillators are considered. Graphical results for 10 ml are also given. (Author) 11 refs

  8. Nanophosphor composite scintillators comprising a polymer matrix

    Science.gov (United States)

    Muenchausen, Ross Edward; Mckigney, Edward Allen; Gilbertson, Robert David

    2010-11-16

    An improved nanophosphor composite comprises surface modified nanophosphor particles in a solid matrix. The nanophosphor particle surface is modified with an organic ligand, or by covalently bonding a polymeric or polymeric precursor material. The surface modified nanophosphor particle is essentially charge neutral, thereby preventing agglomeration of the nanophosphor particles during formation of the composite material. The improved nanophosphor composite may be used in any conventional scintillator application, including in a radiation detector.

  9. Luminescence and energy transfer in Garnet Scintillators

    OpenAIRE

    Ogiegło, J.M.

    2012-01-01

    The thesis is focused on development and fundamental understanding of scintillators that play a central role in the field of medical imaging. These materials convert high energy, gamma or X-ray, radiation into visible light that is then used to create a detailed image of the patient’s body. The power of such imaging techniques as diagnostic medical tools is hard to overestimate.

  10. Solid state scintillators for gamma spectrometry

    International Nuclear Information System (INIS)

    La Mela, G.; Torrisi, M.

    1991-01-01

    Using different scintillator crystals, measurements of energy resolution and detection efficiency have been performed to detect gamma rays of energy ranging between 500 en 1550 KeV. This investigation is devoted to characterize the best systems to detect photons coming from positron annihilation processes, such as a PET apparatus where the medical image is the final aim of the investigation, and gamma emission from radioisotopes of biomedical interest

  11. Liquid scintillator calorimetry for the LHC

    International Nuclear Information System (INIS)

    Artamonov, A.; Buontempo, S.; Epstein, V.; Ereditato, A.; Fiorillo, G.; Garufi, F.; Golovkin, S.; Gorbunov, P.; Jemanov, V.; Khovansky, V.; Kruchinin, S.; Maslennikov, A.; Medvedkov, A.; Vasilchenko, V.; Zaitsev, V.; Zuckerman, I.

    1995-01-01

    We report on the beam tests of full scale liquid scintillator modules designed for a very forward calorimeter for an experiment at the CERN Large Hadron Collider (LHC). Tests were performed in the electron beams of the SPS at CERN within the 20 and 150 GeV energy range. The response as a function of the beam impact point and incidence angle was measured. (orig.)

  12. Chloride, bromide and iodide scintillators with europium

    Science.gov (United States)

    Zhuravleva, Mariya; Yang, Kan

    2016-09-27

    A halide scintillator material is disclosed where the halide may comprise chloride, bromide or iodide. The material is single-crystalline and has a composition of the general formula ABX.sub.3 where A is an alkali, B is an alkali earth and X is a halide which general composition was investigated. In particular, crystals of the formula ACa.sub.1-yEu.sub.yI.sub.3 where A=K, Rb and Cs were formed as well as crystals of the formula CsA.sub.1-yEu.sub.yX.sub.3 (where A=Ca, Sr, Ba, or a combination thereof and X=Cl, Br or I or a combination thereof) with divalent Europium doping where 0.ltoreq.y.ltoreq.1, and more particularly Eu doping has been studied at one to ten mol %. The disclosed scintillator materials are suitable for making scintillation detectors used in applications such as medical imaging and homeland security.

  13. Scintillation counter with MRS APD light readout

    International Nuclear Information System (INIS)

    Akindinov, A.; Bondarenko, G.; Golovin, V.; Grigoriev, E.; Grishuk, Yu.; Mal'kevich, D.; Martemiyanov, A.; Ryabinin, M.; Smirnitskiy, A.; Voloshin, K.

    2005-01-01

    START, a high-efficiency and low-noise scintillation detector for ionizing particles, was developed for the purpose of creating a high-granular system for triggering cosmic muons. Scintillation light in START is detected by MRS APDs (Avalanche Photo-Diodes with Metal-Resistance-Semiconductor Structure), operated in the Geiger mode, which have 1mm 2 sensitive areas. START is assembled from a 15x15x1cm 3 scintillating plastic plate, two MRS APDs and two pieces of wavelength-shifting optical fiber stacked in circular coils inside the plastic. The front-end electronic card is mounted directly on the detector. Tests with START have confirmed its operational consistency, over 99% efficiency of MIP registration and good homogeneity. START demonstrates a low intrinsic noise of about 10 -2 Hz. If these detectors are to be mass-produced, the cost of a mosaic array of STARTs is estimated at a moderate level of 2-3kUSD/m 2

  14. Pulse height model for deuterated scintillation detectors

    International Nuclear Information System (INIS)

    Wang, Haitang; Enqvist, Andreas

    2015-01-01

    An analytical model of light pulse height distribution for finite deuterated scintillation detectors is created using the impulse approximation. Particularly, the energy distribution of a scattered neutron is calculated based on an existing collision probability scheme for general cylindrical shaped detectors considering double differential cross-sections. The light pulse height distribution is analytically and numerically calculated by convoluting collision sequences with the light output function for an EJ-315 detector from our measurements completed at Ohio University. The model provides a good description of collision histories capturing transferred neutron energy in deuterium-based scintillation materials. The resulting light pulse height distribution details pulse compositions and their corresponding contributions. It shows that probabilities of neutron collision with carbon and deuterium nuclei are comparable, however the light pulse amplitude due to collisions with carbon nuclei is small and mainly located at the lower region of the light pulse distribution axis. The model can explore those neutron interaction events that generate pulses near or below a threshold that would be imposed in measurements. A comparison is made between the light pulse height distributions given by the analytical model and measurements. It reveals a significant probability of a neutron generating a small light pulse due to collisions with carbon nuclei when compared to larger light pulse generated by collisions involving deuterium nuclei. This model is beneficial to understand responses of scintillation materials and pulse compositions, as well as nuclei information extraction from recorded pulses.

  15. Boron-Loaded Silicone Rubber Scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Bell, Z.W.; Maya, L.; Brown, G.M.; Sloop, F.V.Jr

    2003-05-12

    Silicone rubber received attention as an alternative to polyvinyltoluene in applications in which the scintillator is exposed to high doses because of the increased resistance of the rubber to the formation of blue-absorbing color centers. Work by Bowen, et al., and Harmon, et al., demonstrated their properties under gamma/x-ray irradiation, and Bell, et al. have shown their response to thermal neutrons. This last work, however, provided an example of a silicone in which both the boron and the scintillator were contained in the rubber as solutes, a formulation which led to the precipitation of solids and sublimation of the boron component. In the present work we describe a scintillator in which the boron is chemically bonded to the siloxane and so avoids the problem of precipitation and loss of boron to sublimation. Material containing up to 18% boron, by weight, was prepared, mounted on photomultipliers, and exposed to both neutron and gamma fluxes. Pulse height spectra showing the neutron and photon response were obtained, and although the light output was found to be much poorer than from samples in which boron was dissolved, the higher boron concentrations enabled essentially 100% neutron absorption in only a few millimeters' thickness of rubber.

  16. New scintillating crystals for PET scanners

    CERN Document Server

    Lecoq, P

    2002-01-01

    Systematic R&D on basic mechanism in inorganic scintillators, initiated by the Crystal Clear Collaboration at CERN 10 years ago, has contributed not to a small amount, to the development of new materials for a new generation of medical imaging devices with increased resolution and sensitivity. The first important requirement for a scintillator to be used in medical imaging devices is the stopping power for the given energy range of X and gamma rays to be considered, and more precisely the conversion efficiency. A high light yield is also mandatory to improve the energy resolution, which is essentially limited by the photostatistics and the electronic noise at these energies. A short scintillation decay time allows to reduce the dead time and therefore to increase the limiting counting rate. When all these requirements are fulfilled the sensitivity and image contrast are increased for a given patient dose, or the dose can be reduced. Examples of new materials under development by the Crystal Clear Collabor...

  17. Scintillating fiber detection development for the SSC

    International Nuclear Information System (INIS)

    Ruchti, R.

    1993-01-01

    SSC Detector Program at Notre Dame has been concentrating on the development of scintillating fiber detectors for tracking applications. Initial work has focused on the development of new scintillation materials for micro-tracking and central tracking detectors based on organic plastics and liquids, This effort has included studies of solvents, solutes and waveguides. Techniques capable of providing the detection of single photons from fibers, are also being developed, leading to a collaboration with Rockwell, UCLA, and UTexas-Dallas groups on the development and application of the Solid State Photomultiplier (SSPM). This initial collaboration has been strengthened and expanded to the formation of a larger collaboration whose goal is to develop a fiber tracking subsystem for SSC, incorporating scintillating fibers and solid state photodetectors. The major subsystem proposal submitted to SSCL by this new collaboration, known at the Fiber Tracking Group (FTG), has been approved and funding is being put in place. The collaboration consists of 12 institutions and Notre Dame is a spokesman group

  18. Composition for use in scintillator systems

    International Nuclear Information System (INIS)

    Tarkkanen, V.

    1976-01-01

    Reference is made to compositions for liquid scintillation counting of aqueous radioactive samples. A composition is described that reduces chemiluminescence on the addition of an alkaline material. Many common sample materials, for example body fluids, are inherently alkaline, whilst samples such as animal tissues are often dissolved in alkaline media. Another problem is water miscibility, and the object is to provide a scintillation counting composition that, when mixed with an aqueous sample, produces a single phase low viscosity mixture over a wide range of water contents and temperatures. The composition described includes a major amount of an aromatic hydrocarbon solvent, a minor amount of an ethoxylated alkyl phenol surfactant, a scintillation solute, an amount of a substituted ethoxylated carboxylic acid sufficient to reduce chemiluminescence, and an amount of a tertiary amine salt or a quaternary ammonium salt of the substituted ethoxylated carboxylic acid sufficient to enhance the water miscibility. The hydrocarbon solvent and the surfactant may be pre-treated with a reactive solid metal hydride to remove peroxides, and then subsequently pre-treated with SO 2 . Examples of the use of the composition are given. (U.K)

  19. Broadband Ionospheric Scintillation Measurements from Space

    Science.gov (United States)

    Suszcynsky, D. M.; Light, M. E.; Pigue, M. J.

    2014-12-01

    The U.S. Department of Energy's Radio Frequency Propagation (RFProp) experiment consists of a satellite-based radio receiver suite to study various aspects of trans-ionospheric signal propagation and detection in four frequency bands, 2 - 55 MHz, 125 - 175 MHz, 365 - 415 MHz and 825 - 1100 MHz. In this paper, we present an overview of the RFProp on-orbit research and analysis effort with particular focus on an equatorial scintillation experiment called ESCINT. The 3-year ESCINT project is designed to characterize equatorial ionospheric scintillation in the upper HF and lower VHF portions of the radio spectrum (20 - 150 MHz). Both a 40 MHz continuous wave (CW) signal and 30 - 42 MHz swept frequency signal are transmitted to the satellite receiver suite from the Reagan Test Site at Kwajalein Atoll in the Marshall Islands (8.7° N, 167.7° E) in four separate campaigns centered on the 2014 and 2015 equinoxes. Results from the first campaign conducted from April 22 - May 15, 2014 will be presented including (a) coherence bandwidth measurements over a full range of transmission frequencies and scintillation activity levels, (b) spread-Doppler clutter effects arising from preferential ray paths to the satellite due to refraction off of isolated density irregularities, and (c) supporting ray-trace simulations. The broadband nature of the measurements is found to offer unique insight into both the structure of ionospheric irregularities and their impact on HF/VHF trans-ionospheric radio wave propagation.

  20. Temperature quenching in LAB based liquid scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Soerensen, A.; Zuber, K. [Technische Universitaet Dresden, Institute for Nuclear- and Particle Physics, Dresden (Germany); Hans, S.; Yeh, M. [Brookhaven National Laboratory, Chemistry Devision, Upton, NY (United States); Junghans, A.R.; Koegler, T.; Wagner, A. [Helmholtz-Zentrum Dresden-Rossendorf, Dresden (Germany); Krosigk, B. v. [Technische Universitaet Dresden, Institute for Nuclear- and Particle Physics, Dresden (Germany); University of British Columbia, Department of Physics and Astronomy, Vancouver, BC (Canada); Lozza, V. [Technische Universitaet Dresden, Institute for Nuclear- and Particle Physics, Dresden (Germany); Laboratorio de Instrumentacao e Fisica Experimental de Particulas, Lisboa (Portugal)

    2018-01-15

    The effect of temperature changes on the light output of LAB based liquid scintillator is investigated in a range from -5 to 30 C with α-particles and electrons in a small scale setup. Two PMTs observe the scintillator liquid inside a cylindrically shaped aluminum cuvette that is heated or cooled and the temperature dependent PMT sensitivity is monitored and corrected. The α-emitting isotopes in dissolved radon gas and in natural Samarium (bound to a LAB solution) excite the liquid scintillator mixtures and changes in light output with temperature variation are observed by fitting light output spectra. Furthermore, also changes in light output by compton electrons, which are generated from external calibration γ-ray sources, is analysed with varying temperature. Assuming a linear behaviour, a combined negative temperature coefficient of (-0.29 ± 0.01)%/ C is found. Considering hints for a particle type dependency, electrons show (-0.17 ± 0.02)%/ C, whereas the temperature dependency seems stronger for α-particles, with (-0.35 ± 0.03)%/ C. Due to a high sampling rate, a pulse shape analysis can be performed and shows an enhanced slow decay component at lower temperatures, pointing to reduced non-radiative triplet state de-excitations. (orig.)

  1. Efficiency and yield spectra of inorganic scintillates

    International Nuclear Information System (INIS)

    Rodnyi, P.A.

    1998-01-01

    Recent developments in the field of energy loss in inorganic scintillators are reviewed. The main parameters, which control the fundamental limit of the scintillator energy efficiency, are determined. It is shown that together with simple cascade processes one should take into account the production of plasmons to estimate the energy efficiency of scintillators or other phosphors excited by an ionizing radiation. Core-to-valence luminescence related to 5pCs→3pCl transitions is investigated in some chlorides: CsCl, KCl, RbCl, NaCl, KCaCl 3 , RbCaCl 3 . The yield spectra of the crystals in the VUV and X-ray regions are also studied. It is shown that the 4pRb-core states are involved in the process of creation of holes in the 5pCs-core band in Rb-based crystals. The formation of holes in the potassium core band acts as a competing process and suppresses the radiative core-to-valence transitions

  2. Linearity correction device for a scintillation camera

    Energy Technology Data Exchange (ETDEWEB)

    Lange, Kai

    1978-06-16

    This invention concerns the scintillation cameras still called gamma ray camera. The invention particularly covers the improvement in the resolution and the uniformity of these cameras. Briefly, in the linearity correction device of the invention, the sum is made of the voltage signals of different amplitudes produced by the preamplifiers of all the photomultiplier tubes and the signal obtained is employed to generate bias voltages which represent predetermined percentages of the sum signal. In one design mode, pairs of transistors are blocked when the output signal of the corresponding preamplifier is under a certain point on its gain curve. When the summation of the energies of a given scintillation exceeds this level which corresponds to a first percentage of the total signal, the first transistor of each pair of each line is unblocked, thereby modifying the gain and curve slop. When the total energy of an event exceeds the next preset level, the second transistor is unblocked to alter the shape again, so much so that the curve shows two break points. If needs be, the device can be designed so as to obtain more break points for the increasingly higher levels of energy. Once the signals have been processed as described above, they may be used for calculating the co-ordinates of the scintillation by one of the conventional methods.

  3. Characteristics of plastic scintillators fabricated by a polymerization reaction

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Cheol Ho; Son, Jaebum; Kim, Tae Hoon; Kim, Yong Kyun [Dept. of Nuclear Engineering, Hanyang University, Seoul (Korea, Republic of)

    2017-04-15

    Three plastic scintillators of 4.5 cm diameter and 2.5-cm length were fabricated for comparison with commercial plastic scintillators using polymerization of the styrene monomer 2.5-diphenyloxazole (PPO) and 1,4-bis benzene (POPOP). Their maximum emission wavelengths were determined at 426.06 nm, 426.06 nm, and 425.00 nm with a standard error of 0.2% using a Varian spectrophotometer (Agilent, Santa Clara, CA, USA). Compton edge spectra were measured using three gamma ray sources [i.e., cesium 137 ({sup 137}Cs), sodium 22 ({sup 22}Na), and cobalt 60 ({sup 60}Co)]. Energy was calibrated by analyzing the Compton edge spectra. The fabricated scintillators possessed more than 99.7% energy linearity. Light output was comparable to that of the BC-408 scintillator (Saint-Gobain, Paris, France). The fabricated scintillators showed a light output of approximately 59–64% of that of the BC-408 scintillator.

  4. Methods for the continuous production of plastic scintillator materials

    Science.gov (United States)

    Bross, Alan; Pla-Dalmau, Anna; Mellott, Kerry

    1999-10-19

    Methods for producing plastic scintillating material employing either two major steps (tumble-mix) or a single major step (inline-coloring or inline-doping). Using the two step method, the polymer pellets are mixed with silicone oil, and the mixture is then tumble mixed with the dopants necessary to yield the proper response from the scintillator material. The mixture is then placed in a compounder and compounded in an inert gas atmosphere. The resultant scintillator material is then extruded and pelletized or formed. When only a single step is employed, the polymer pellets and dopants are metered into an inline-coloring extruding system. The mixture is then processed under a inert gas atmosphere, usually argon or nitrogen, to form plastic scintillator material in the form of either scintillator pellets, for subsequent processing, or as material in the direct formation of the final scintillator shape or form.

  5. Liquid emulsion scintillators which solidify for facile disposal

    International Nuclear Information System (INIS)

    O'Brien, R.E.; Krieger, J.K.

    1981-01-01

    A liquid organic scintillation cocktail is described which counts solutions of radiolabelled compounds containing up to ten % by volume of water with high efficiency and is readily polymerizable to a solid for easy disposal. The cocktail comprises a polymerizable organic solvent, a solubilizing agent, an intermediate solvent, and an organic scintillator. A method of disposing of liquid organic scintillation cocktail waste and a kit useful for practising the method are also described. (U.K.)

  6. Some results of ionospheric scintillation observations at Lumping

    International Nuclear Information System (INIS)

    Huang, Yinn-Nien

    1983-01-01

    The ionospheric scintillation data obtained at Lunping by use of 136.1124 MHz beacon signal transmitted from the geostationary satellite, ETS-2, have been used to analyze the diurnal, seasonal and solar cycle variations of scintillation activity. The effect of the geomagnetic activity on the scintillation activity has been studied by use of superposed epoch method. The effect is not unique but depends on season and solar activity. (author)

  7. A Scintillator Purification System for the Borexino Solar Neutrino Detector

    OpenAIRE

    Benziger, J.; Cadonati, L.; Calaprice, F.; Chen, M.; Corsi, A.; Dalnoki-Veress, F.; Fernholz, R.; Ford, R.; Galbiati, C.; Goretti, A.; Harding, E.; Ianni, Aldo; Ianni, Andrea; Kidner, S.; Leung, M.

    2007-01-01

    Purification of the 278 tons of liquid scintillator and 889 tons of buffer shielding for the Borexino solar neutrino detector was performed with a system that combined distillation, water extraction, gas stripping and filtration. The purification of the scintillator achieved unprecedented low backgrounds for the large scale liquid scintillation detector. This paper describes the principles of operation, design, construction and commissioning of the purification system, and reviews the require...

  8. Systematic studies of small scintillators for new sampling calorimeter

    International Nuclear Information System (INIS)

    Jacosalem, E.P.; Sanchez, A.L.C.; Bacala, A.M.; Iba, S.; Nakajima, N.; Ono, H.; Miyata, H.

    2007-01-01

    A new sampling calorimeter using very thin scintillators and the multi-pixel photon counter (MPPC) has been proposed to produce better position resolution for the international linear collider (ILC) experiment. As part of this R and D study, small plastic scintillators of different sizes, thickness and wrapping reflectors are systematically studied. The scintillation light due to beta rays from a collimated 90 Sr source are collected from the scintillator by wavelength-shifting (WLS) fiber and converted into electrical signals at the PMT. The wrapped scintillator that gives the best light yield is determined by comparing the measured pulse height of each 10 x 40 x 2 mm strip scintillator covered with 3M reflective mirror film, teflon, white paint, black tape, gold, aluminum and white paint+teflon. The pulse height dependence on position, length and thickness of the 3M reflective mirror film and teflon wrapped scintillators are measured. Results show that the 3M radiant mirror film-wrapped scintillator has the greatest light yield with an average of 9.2 photoelectrons. It is observed that light yield slightly increases with scintillator length, but increases to about 100% when WLS fiber diameter is increased from 1.0 mm to 1.6 mm. The position dependence measurement along the strip scintillator showed the uniformity of light transmission from the sensor to the PMT. A dip across the strip is observed which is 40% of the maximum pulse height. The block type scintillator pulse height, on the other hand, is found to be almost proportional to scintillator thickness. (author)

  9. New heavy scintillating materials for precise heterogeneous EM-calorimeters

    International Nuclear Information System (INIS)

    Britvich, G.I.; Britvich, I.G.; Vasil'chenko, V.G.; Lishin, V.A.; Obraztsov, V.F.; Polyakov, V.A.; Solovjev, A.S.; Ryzhikov, V.D.

    2001-01-01

    This investigation shows some optical and scintillation properties of new scintillating media, based on heavy composite materials and an inorganic crystal CsI:Br, intended for the creation of precise heterogeneous EM-calorimeters with the energy resolution σ/E congruent with 4-5% E-radical. The possibility to use cheap heavy scintillating plates based on optical ceramics as active media in heterogeneous EM-calorimeters is considered

  10. Paraffin scintillator for radioassay of solid support samples

    International Nuclear Information System (INIS)

    Fujii, Haruo; Takiue, Makoto

    1989-01-01

    A new paraffin scintillator used for solid support sample counting has been proposed, and its composition and various characteristics are described. The solid support sample treated with this scintillator can be easily handled because of rigid sample conditions. This technique provides great advantages such as the elimination of a large volume of scintillator and little radioactive waste material by using an economical polyethylene bag instead of the conventional counting vial. (author)

  11. Growth and scintillation properties of gadolinium and yttrium orthovanadate crystals

    International Nuclear Information System (INIS)

    Voloshina, O.V.; Baumer, V.N.; Bondar, V.G.; Kurtsev, D.A.; Gorbacheva, T.E.; Zenya, I.M.; Zhukov, A.V.; Sidletskiy, O.Ts.

    2012-01-01

    Aiming to explore the possibility of using the undoped rare-earth orthovanadates as scintillation materials, we developed the procedure for growth of gadolinium (GdVO 4 ) and yttrium (YVO 4 ) orthovanadate single crystals by Czochralski method, and determined the optimal conditions of their after-growth annealing. Optical, luminescent, and scintillation properties of YVO 4 and GdVO 4 were discussed versus known literature data. Scintillation characteristics of GdVO 4 were determined for the first time.

  12. Ionospheric scintillation observations over Kenyan region - Preliminary results

    Science.gov (United States)

    Olwendo, O. J.; Xiao, Yu; Ming, Ou

    2016-11-01

    Ionospheric scintillation refers to the rapid fluctuations in the amplitude and phase of a satellite signal as it passes through small-scale plasma density irregularities in the ionosphere. By analyzing ionospheric scintillation observation datasets from satellite signals such as GPS signals we can study the morphology of ionospheric bubbles. At low latitudes, the diurnal behavior of scintillation is driven by the formation of large-scale equatorial density depletions which form one to two hours after sunset via the Rayleigh-Taylor instability mechanism near the magnetic equator. In this work we present ionospheric scintillation activity over Kenya using data derived from a newly installed scintillation monitor developed by CRIRP at Pwani University (39.78°E, 3.24°S) during the period August to December, 2014. The results reveal the scintillation activity mainly occurs from post-sunset to post-midnight hours, and ceases around 04:00 LT. We also found that the ionospheric scintillation tends to appear at the southwest and northwest of the station. These locations coincide with the southern part of the Equatorial Ionization Anomaly crest over Kenya region. The occurrence of post-midnight L-band scintillation events which are not linked to pre-midnight scintillation observations raises fundamental question on the mechanism and source of electric fields driving the plasma depletion under conditions of very low background electron density.

  13. Organic scintillators with long luminescent lifetimes for radiotherapy dosimetry

    DEFF Research Database (Denmark)

    Beierholm, Anders Ravnsborg; Lindvold, Lars René; Andersen, Claus Erik

    2011-01-01

    of experiments performed using two organic scintillators, one commercially available and one custom made. The luminescent lifetimes of the scintillators have been measured using i) optical excitation by pulsed UV light, and ii) irradiative excitation using high-energy X-rays from a linac. A luminescent lifetime...... component on the order of 20 μs was estimated for the custom-made organic scintillator, while the commercial scintillator exhibited a fast component of approximately 5 ns lifetime (7 ns as stated by the manufacturer) and an approximate 10 μs lifetime slow component. Although these lifetimes are not long...

  14. Radiation converter scintillator screen and its manufacturing process

    International Nuclear Information System (INIS)

    Delattre, D.; Rougeot, H.; Tassin, C.

    1984-01-01

    The present invention concerns scintillating screens receiving X or gamma radiation and converting it in luminous photons. The screen comprises a needle structure scintillating material. Its concave surface is quite smooth. The screen is obtained by evaporation on a frame having a perfectly smooth convex surface; the constituting material has a thermal dilatation coefficient different from the scintillating material one. After evaporation, the scintillating screen is set apart from the frame by simple heating. It is used for radiological image intensifier tubes and scintigraphy tubes [fr

  15. Radiation-induced chemical processes in polystyrene scintillators

    International Nuclear Information System (INIS)

    Milinchuk, V.K.; Bolbit, N.M.; Klinshpont, E.R.; Tupikov, V.I.; Zhdanov, G.S.; Taraban, S.B.; Shelukhov, I.P.; Smoljanskii, A.S.

    1999-01-01

    The regularities established for macroradical accumulation and intensity of radioluminescence under γ-irradiation of a polystyrene scintillator prove benzyl macroradicals to be efficient quenchers of the excited scintillator molecules. Dissolved oxygen was determined to have a constant of the quenching rate 100 times lower than that of macroradicals. Oxygen is an efficient antirad because of participating in oxidation reactions and subsequent recombination of macroradicals. The method was developed to obtain a polymeric scintillator with a polystyrene matrix containing a dispersed system of pores and channels. Radiation resistance of such a scintillator is 5-10 times higher than that of standard types

  16. Study on determination of 90Sr by liquid scintillation spectrometry

    International Nuclear Information System (INIS)

    Zhai Xiufang; Li Weiping; Tian Mei; Zou Ronghu

    2012-01-01

    Both of Liquid scintillation counting and Cerenkov counting can be used to determinate 90 Sr in samples by Liquid scintillation spectrometry. In this work, effects of scintillation vials wit-h different material, Liquid scintillation cocktails, sample volume, Strontium carrier, pH, quenching (chemical quenching and color quenching)are studied, and both counting methods are compared. For Liquid scintillation counting. The results show that the best appropriate volume ratio of sample and liquid scintillation cocktail is 8:12 for OPTIPHASE HISAFE-3 and OPTIPHASE HISAFE-2, stability of solution decreased when sample load exceeds the maximum load for both Liquid scintillation cocktails, and OPTIPHASE HISAFE-3 also show superior performance for high saline solution. The type of scintillation vial haven't clear influence on the MDA of 90 Sr. Chemical quenching and color quenching can decrease the counting efficiency. For Cerenkov counting, the lowest MDA is obtained when polyethylene plastic vial is used and sample volume is 20 ml. Color quenching decreases the counting efficiency, while there isn't chemical quenching for Cerenkov counting. The MDA of 90 Sr is 1.19 and 1.00 Bq/L for Liquid scintillation counting and Cerenkov counting with the optimal labeling condition. (authors)

  17. Report on radiation exposure of lead-scintillator stack

    International Nuclear Information System (INIS)

    Underwood, D.G.

    1990-01-01

    A stack of lead and scintillator was placed in a neutral beam obtained from targeting 800 GeV protons. Small pieces of film containing radiochromic dye were placed adjacent to the layers of scintillator for the purpose of measuring the radiation dose to the scintillator. Our motivation was to calibrate the radiation dose obtainable in this manner for future tests of scintillator for SSC experiments and to relate dose to flux to check absolute normalization for calculations. We also observed several other radiation effects which should be considered for both damage and compensation in a calorimeter

  18. 2003: A centennial of spinthariscope and scintillation counting

    International Nuclear Information System (INIS)

    Kolar, Z.I.; Hollander, W. den

    2004-01-01

    In 1903 W. Crookes demonstrated in England his 'spinthariscope' for the visual observation of individual scintillations caused by alpha particles impinging upon a ZnS screen. In contrast to the analogue methods of radiation measurements in that time the spinthariscope was a single-particle counter, being the precursor of scintillation counters since. In the same period F. Giesel, J. Elster and H. Geitel in Germany also found that scintillations from ZnS represent single particle events. This paper summarises the historical events relevant to the advent of scintillation counting

  19. Liquid-helium scintillation detection with germanium photodiodes

    International Nuclear Information System (INIS)

    Luke, P.N.; Haller, E.E.; Steiner, H.M.

    1982-05-01

    Special high-purity germanium photodiodes have been developed for the direct detection of vacuum ultraviolet scintillations in liquid helium. The photodiodes are immersed in the liquid helium, and scintillations are detected through one of the bare sides of the photodiodes. Test results with scintillation photons produced by 5.3-MeV α particles are presented. The use of these photodiodes as liquid-helium scintillation detectors may offer substantial improvements over the alternate detection method requiring the use of wavelength shifters and photomultiplier tubes

  20. Investigation of organic liquid-scintillator optical properties

    Energy Technology Data Exchange (ETDEWEB)

    Winter, Juergen; Feilitzsch, Franz von; Goeger-Neff, Marianne; Lewke, Timo; Meindl, Quirin; Oberauer, Lothar; Potzel, Walter; Todor, Sebastian; Wurm, Michael [Physik Department E15, Technische Universitaet Muenchen, James-Franck-Str., 85748 Garching (Germany); Marrodan Undagoitia, Teresa [Physik Department E15, Technische Universitaet Muenchen, James-Franck-Str., 85748 Garching (Germany); Physik-Institut, Universitaet Zuerich (Switzerland)

    2009-07-01

    The characterization of different organic liquid-scintillator mixtures is an important step towards the design of a large-scale detector such as LENA (Low Energy Neutrino Astronomy). Its physics goals, extending from particle and geological to astrophysical issues, set high demands on the optical properties of the liquid scintillator. Therefore, small-scale experiments are carried out in order to optimize the final scintillator mixture. PXE, LAB, and dodecane are under consideration as solvents. Setups for the determination of scintillator properties are presented, such as attenuation length, light yield, emission spectra, fluorescence decay times, and quenching factors. Furthermore, results are discussed.

  1. An efficient energy response model for liquid scintillator detectors

    Science.gov (United States)

    Lebanowski, Logan; Wan, Linyan; Ji, Xiangpan; Wang, Zhe; Chen, Shaomin

    2018-05-01

    Liquid scintillator detectors are playing an increasingly important role in low-energy neutrino experiments. In this article, we describe a generic energy response model of liquid scintillator detectors that provides energy estimations of sub-percent accuracy. This model fits a minimal set of physically-motivated parameters that capture the essential characteristics of scintillator response and that can naturally account for changes in scintillator over time, helping to avoid associated biases or systematic uncertainties. The model employs a one-step calculation and look-up tables, yielding an immediate estimation of energy and an efficient framework for quantifying systematic uncertainties and correlations.

  2. Production low cost plastic scintillator by using commercial polystyrene

    International Nuclear Information System (INIS)

    2011-01-01

    Plastic Scintillators can be described as solid materials which contain organic fluorescent compounds dissolved within a polymer matrix. Transparent plastics commonly used for light scintillation are Polystyrene (or PS, poly-vinyl-benzene) and polyvinyl-toluene (or PVT, poly-methyl-styron). By changing the composition of plastic Scintillators some features such as light yield, radiation hardening, decay time etc. can be controlled. Plastic scintillation detectors have been used in nuclear and high energy physics for many decades. Among their benefits are fast response, ease of manufacture and versatility. Their main drawbacks are radiation resistance and cost. Many research projects have concentrated on improving the fundamental properties of plastic scintillators, but little attention has focussed on their cost and easier manufacturing techniques. First plastic Scintillators were produced in 1950's. Activities for production of low cost Scintillators accelerated in second half of 1970's. In 1975 acrylic based Plexipop Scintillator was developed. Despite its low cost, since its structure was not aromatic the light yield of Plexipop was about one quarter of classical Scintillators. Problems arising from slow response time and weak mechanical properties in scintillators developed, has not been solved until 1980. Within the last decade extrusion method became very popular in preparation of low cost and high quality plastic scintillators. In this activity, preliminary studies for low cost plastic scintillator production by using commercial polystyrene pellets and extrusion plus compression method were aimed. For this purpose, PS blocks consist of commercial fluorescent dopant were prepared in June 2008 by use of the extruder and pres in SANAEM. Molds suitable for accoupling to extruder were designed and manufactured and optimum production parameters such as extrusion temperature profile, extrusion rate and moulding pressure were obtained hence, PS Scintillator Blocks

  3. Cesium hafnium chloride scintillator coupled with an avalanche photodiode photodetector

    Czech Academy of Sciences Publication Activity Database

    Kurosawa, S.; Kodama, S.; Yokota, Y.; Horiai, T.; Yamaji, A.; Shoji, Y.; Král, Robert; Pejchal, Jan; Ohashi, Y.; Kamada, K.; Nikl, Martin; Yoshikawa, A.

    2017-01-01

    Roč. 12, Feb (2017), s. 1-8, č. článku C02042. ISSN 1748-0221 Grant - others:AV ČR(CZ) JSPS-17-18 Program:Bilaterální spolupráce Institutional support: RVO:68378271 Keywords : gamma detectors * scintillators and scintillating fibres * scintillators * scintillation and light emission processes Subject RIV: BM - Solid Matter Physics ; Magnetism OBOR OECD: Condensed matter physics (including formerly solid state physics, supercond.) Impact factor: 1.220, year: 2016

  4. Lanthanide doped strontium-barium cesium halide scintillators

    Science.gov (United States)

    Bizarri, Gregory; Bourret-Courchesne, Edith; Derenzo, Stephen E.; Borade, Ramesh B.; Gundiah, Gautam; Yan, Zewu; Hanrahan, Stephen M.; Chaudhry, Anurag; Canning, Andrew

    2015-06-09

    The present invention provides for a composition comprising an inorganic scintillator comprising an optionally lanthanide-doped strontium-barium, optionally cesium, halide, useful for detecting nuclear material.

  5. Hybrid inorganic-organic polymer electrolytes: synthesis, FT-Raman studies and conductivity of {l_brace}Zr[(CH{sub 2}CH{sub 2}O){sub 8.7}]{sub {rho}}/(LiClO{sub 4}){sub z}{r_brace}{sub n} network complexes

    Energy Technology Data Exchange (ETDEWEB)

    Di Noto, Vito; Zago, Vanni; Biscazzo, Simone; Vittadello, Michele

    2003-01-15

    This paper describes the synthesis and characterization of three-dimensional hybrid inorganic-organic networks prepared by a polycondensation reaction between Zr(O(CH{sub 2}){sub 3}CH{sub 3}){sub 4} and polyethylene glycol 400 (PEG400). Eleven hybrid networks doped with varying concentrations of LiClO{sub 4} salt were prepared. On the basis of analytical data and FT-Raman studies it was concluded that these polymer electrolytes consist of inorganic-organic networks with zirconium atoms bonded together by PEG400 bridges. These polymers are transparent with a solid rubber consistency and are very stable under inert atmosphere. Scanning electron microscopy revealed a smooth glassy surface. X-ray fluorescence microanalysis with energy dispersive spectroscopy demonstrated that all the constituent elements are homogeneously distributed in the materials. Thermogravimetric measurements revealed that these materials are thermally stable up to 262 deg. C. Differential Scanning Calorimetry measurements indicated that the glass transition temperature T{sub g} of these inorganic-organic hybrids varies from -43 to -15 deg. C with increasing LiClO{sub 4} concentration. FT-Raman investigations revealed the TGT (T=trans, G=gauche) conformation of polyether chains and allowed characterization of the types of ion-ion and ion-polymer host interactions in the bulk materials. The conductivity of the materials at different temperatures was determined by impedance spectroscopy over the 20 Hz-1 MHz frequency range. Results indicated that the materials conduct ionically and that their ionic conductivity is strongly influenced by the segmental motion of the polymer network and the type of ionic species distributed in the bulk material. Finally, it is to be highlighted that the hybrid network with a n{sub Li}/n{sub O} molar ratio of 0.0223 shows a conductivity of ca. 1x10{sup -5} S cm{sup -1} at 40 deg. C.

  6. VHF Scintillation in an Artificially Heated Ionosphere

    Science.gov (United States)

    Suszcynsky, D. M.; Layne, J.; Light, M. E.; Pigue, M. J.; Rivera, L.

    2017-12-01

    As part of an ongoing project to characterize very-high-frequency (VHF) radio wave propagation through structured ionospheres, Los Alamos National Laboratory has been conducting a set of experiments to measure the scintillation effects of VHF transmissions under a variety of ionospheric conditions. Previous work (see 2015 Fall AGU poster by D. Suszcynsky et al.) measured the S4 index and ionospheric coherence bandwidth in the 32 - 44 MHz frequency range under naturally scintillated conditions in the equatorial region at Kwajalein Atoll during three separate campaigns centered on the 2014 and 2015 equinoxes. In this paper, we will present preliminary results from the February and September, 2017 High Altitude Auroral Research Project (HAARP) Experimental Campaigns where we are attempting to make these measurements under more controlled conditions using the HAARP ionospheric heater in a twisted-beam mode. Two types of measurements are made by transmitting VHF signals through the heated ionospheric volume to the Radio Frequency Propagation (RFProp) satellite experiment. The S4 scintillation index is determined by measuring the power fluctuations of a 135-MHz continuous wave signal and the ionospheric coherence bandwidth is simultaneously determined by measuring the delay spread of a frequency-modulated continuous wave (FMCW) signal in the 130 - 140 MHz frequency range. Additionally, a spatial Fourier transform of the CW time series is used to calculate the irregularity spectral density function. Finally, the temporal evolution of the time series is used to characterize spread-Doppler clutter effects arising from preferential ray paths to the satellite due to refraction off of isolated density irregularities. All results are compared to theory and scaled for comparison to the 32 - 44 MHz Kwajalein measurements.

  7. AA, beam stopper with scintillator screen

    CERN Multimedia

    CERN PhotoLab

    1980-01-01

    An insertable steel-plate beam stopper was located after nearly a full turn downstream of the injection point. It was fitted with a scintillator screen, a thin plate of Cr-doped alumina, imprinted with a grid and reference points. The screen was illuminated through a window and observed with a highly sensitive TV camera plus image intensifier. This allowed observation of beam position and size of a proton test beam and of the beam from the target, which consisted not only of antiprotons but contained as well electrons, pions and muons of the same momentum.

  8. Scintillating Fibre Calorimetry at the LHC

    CERN Multimedia

    2002-01-01

    Good electromagnetic and hadronic calorimetry will play a central role in an LHC detector. The lead/scintillating fibre calorimeter technique provides a fast signal response well matched to the LHC rate requirements. It can be made to give equal response for electrons and hadrons (compensation) with good electromagnetic and hadronic energy resolutions.\\\\ \\\\ The aim of this R&D proposal is to study in detail the aspects that are relevant for application of this type of calorimeter in an LHC environment, including its integration in a larger system of detectors, e.g.~projective geometry, radiation hardness, light detection, calibration and stability monitoring, electron/hadron separation.....

  9. Marine radioactivity measurements with liquid scintillation spectrometers

    International Nuclear Information System (INIS)

    Liong Wee Kwong, L.; Povinec, P.P.

    1999-01-01

    Liquid Scintillation Spectrometry (LSS) has now become the most widespread method for quantitative analytical measurement of low levels of β-emitting radionuclides like 3 H and 14 C. The high efficiency resulting from the latest development in LSS makes this technique not only appropriate but also enables direct measurement in environmental samples without excessive preparation. The introduction of several new cocktails based on solvents with a high flashpoint containing surfactants and having a high degree of aqueous sample compatibility has also contributed to the simplification of procedures

  10. Scintillating ribbon x-ray detector

    International Nuclear Information System (INIS)

    Kinchen, B.E.; Rogers, A.

    1995-01-01

    A patent in the early 1970's by Aerojet Corporation in Sacramento, CA put forth the idea of using an array of scintillating fibers for x-ray detection and imaging. In about 1975, Pratt and Whitney Aircraft in East Hartford, CT designed and manufactured an imaging system based on the patent. The device was 1.75 in thick in the direction of the x-ray beam and about 4 in. by 4 in. square. The device was used with a 8 MeV x-ray source to image and measure internal clearances within operating aircraft, gas turbines engines. There are significant advantages of fiber optic detectors in x-ray detection. However, the advantages are often outweighed by the disadvantages. Two of the advantages of scintillating fiber optic x-ray detectors are: (1) high limiting spatial frequency -- between 20 and 25 lp/mm; and (2) excellent x-ray stopping power -- they can be made thick and retain spatial resolution. In traditional fiber optic detectors the x-rays are oriented parallel to the long axis of the fiber. For the scintillating ribbon x-ray sensor, the x-rays are oriented normal to the fiber long axis. This ribbon sensor technique has a number of advantages over the two current radiographic techniques digital x-radiography and x-ray film: The main advantage the ribbon has is size and shape. It can be as thin as 0.05 in., virtually any width or length, and flexible. Once positioned in a given location, 20 to 100 square inches of the object being inspected can be imaged with a single x-ray beam sweep. It is clear that conventional digital cameras do not lend themselves to placement between walls of aircraft structures or similar items requiring x-ray inspections. A prototype scintillating ribbon x-ray sensor has been fabricated and tested by Synergistic Detector Designs. Images were acquired on corrosion test panels of aluminum fabricated by Iowa State University

  11. Collimator trans-axial tomographic scintillation camera

    International Nuclear Information System (INIS)

    Jaszczak, R.J.

    1977-01-01

    A collimator is provided for a scintillation camera system in which a detector precesses in an orbit about a patient. The collimator is designed to have high resolution and lower sensitivity with respect to radiation traveling in paths laying wholly within planes perpendicular to the cranial-caudal axis of the patient. The collimator has high sensitivity and lower resolution to radiation traveling in other planes. Variances in resolution and sensitivity are achieved by altering the length, spacing or thickness of the septa of the collimator

  12. Compositions and process for liquid scintillation counting

    International Nuclear Information System (INIS)

    Kauffman, J.M.

    1976-01-01

    Liquid scintillation counting compositions which include certain polyethoxylated poly(oxypropylene) emulsifiers allow stable dispersion of aqueous or other samples merely by shaking. Preferred are mixtures of such emulsifiers, which give homogeneous, monophasic-appearing dispersions over wide ranges of temperature and aqueous sample content. Certain of these emulsifiers, without being mixed, are of particular advantage when used in analysis of samples obtained through radioimmunoassay techniques, which are extremely difficult to disperse. Certain of these emulsifiers, also without being mixed, uniformly give homogeneous, monophasic appearing aqueous couting samples over much wider ranges of aqueous sample content and temperature than prior sample emulsifiers

  13. Compositions and process for liquid scintillation counting

    International Nuclear Information System (INIS)

    Kauffman, J.M.

    1978-01-01

    Liquid scintillation compositions which include certain polyethoxylated poly(oxypropylene) emulsifiers allow stable dispersion of aqueous or other samples merely by shaking. Preferred are mixtures of such emulsifiers, which give homogeneous, monophasic-appearing dispersions over wide ranges of temperature and aqueous sample content. Certain of these emulsifiers, without being mixed, are of particular advantage when used in analysis of samples obtained through radioimmunoassay techniques, which are extremely difficult to disperse. Certain of these emulsifiers, also without being mixed, uniformly give homogeneous, monophasic appearing aqueous counting samples over much wider ranges of aqueous sample content and temperature than prior sample emulsifiers

  14. Fundamental limits of scintillation detector timing precision

    International Nuclear Information System (INIS)

    Derenzo, Stephen E; Choong, Woon-Seng; Moses, William W

    2014-01-01

    In this paper we review the primary factors that affect the timing precision of a scintillation detector. Monte Carlo calculations were performed to explore the dependence of the timing precision on the number of photoelectrons, the scintillator decay and rise times, the depth of interaction uncertainty, the time dispersion of the optical photons (modeled as an exponential decay), the photodetector rise time and transit time jitter, the leading-edge trigger level, and electronic noise. The Monte Carlo code was used to estimate the practical limits on the timing precision for an energy deposition of 511 keV in 3 mm × 3 mm × 30 mm Lu 2 SiO 5 :Ce and LaBr 3 :Ce crystals. The calculated timing precisions are consistent with the best experimental literature values. We then calculated the timing precision for 820 cases that sampled scintillator rise times from 0 to 1.0 ns, photon dispersion times from 0 to 0.2 ns, photodetector time jitters from 0 to 0.5 ns fwhm, and A from 10 to 10 000 photoelectrons per ns decay time. Since the timing precision R was found to depend on A −1/2  more than any other factor, we tabulated the parameter B, where R = BA −1/2 . An empirical analytical formula was found that fit the tabulated values of B with an rms deviation of 2.2% of the value of B. The theoretical lower bound of the timing precision was calculated for the example of 0.5 ns rise time, 0.1 ns photon dispersion, and 0.2 ns fwhm photodetector time jitter. The lower bound was at most 15% lower than leading-edge timing discrimination for A from 10 to 10 000 photoelectrons ns −1 . A timing precision of 8 ps fwhm should be possible for an energy deposition of 511 keV using currently available photodetectors if a theoretically possible scintillator were developed that could produce 10 000 photoelectrons ns −1 . (paper)

  15. Compositions and process for liquid scintillation counting

    International Nuclear Information System (INIS)

    1974-01-01

    Liquid scintillation counting compositions which include certain polyethoxylated poly(oxypropylene) emulsifiers allow stable dispersion of aqueous or other samples merely by shaking. Preferred are mixtures of such emulsifiers which give homogeneous monophasic-appearing dispersions over wide ranges of temperature and aqueous sample content. Certain of these emulsifiers, without being mixed, are of particular advantage when used in analysis of samples obtained through radioimmunoassay techniques which are extremely difficult to disperse. Certain of these emulsifiers, also without being mixed, uniformly give homogeneous monophasic-appearing aqueous counting samples over much wider ranges of aqueous sample content and temperature than prior sample emulsifiers

  16. A fast readout system for scintillation detectors

    International Nuclear Information System (INIS)

    Steijger, J.; Kok, E.; Kwakkel, E.; Visschers, J.L.; Zwart, A.N.M.

    1991-01-01

    A system of fast readout electronics for segmented scintillation detectors has been constructed and is now operational. Instead of delaying the analog signals in long coaxial cables, they are digitized immediately and stored in dual-port memories, while the trigger decision is being made. A VMEbus system collects the data from these memories on the data acquisition modules within one crate. Several VME crates are connected via a transputer network to transport the data to an event builder. A separate transputer network is used to perform the VME cycles, needed for the computer-controlled tuning of the experiment. (orig.)

  17. Scintillation {gamma} spectrography. Physical principles. Apparatus. Operation; Spectrographie {gamma} a scintillations. Principes physiques. Appareillage. Utilisation

    Energy Technology Data Exchange (ETDEWEB)

    Julliot, C. [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1960-07-01

    The scintillation detector forms the main part of the instrument used, the electronic unit presenting the results produced. After a brief description of the process of {gamma} photon absorption in the material, the particular case of NaI (T1), the scintillator used, is examined. The intensity of the scintillation caused by {gamma} ray absorption and the characteristics of the photomultiplier play a determining part in the energy resolution of the instrument. For the {gamma} recording spectrograph, we show to what extent the technique for using the electronic unit can modify the results. A detailed description is given of the activity measurement of a {gamma}-emitting radioelement by the spectrographic method. (author) [French] Dans l'appareillage utilise, le detecteur a scintillations constitue la piece maitresse, l'ensemble electronique presente les resultats issus du detecteur. Apres avoir brievement decrit le processus d'absorption des photons {gamma} dans la matiere, nous examinons le cas particulier du NaI(T1), le scintillateur utilise. L'intensite de la scintillation provoque par l'absorption des rayons {gamma} et les caracteristiques du photomultiplicateur jouent un role determinant dans la resolution en energie de l'appareil. Pour le spectrographe {gamma} enregistreur, nous indiquons dans quelle mesure la technique d'utilisation de l'ensemble electronique peut modifier les resultats. La-mesure de l'activite d'un radioelement emetteur {gamma} par spectrographie fait l'objet d'une description detaillee. (auteur)

  18. Optimization of light collection from crystal scintillators for cryogenic experiments

    International Nuclear Information System (INIS)

    Mokina, V.M.; Danevich, F.A.; Kobychev, V.V.; Kraus, H.; Mikhailik, V.B.; Nagornaya, L.L.

    2012-01-01

    Cryogenic scintillation bolometers are a promising technique to search for dark matter and neutrinoless double decay. Improvement of light collection and energy resolution are important requirements in such experiments. Energy resolutions and relative pulse amplitudes of scintillation detectors using ZnWO 4 scintillation crystals of different shapes (cylinder 20x20 mm and hexagonal prism with diagonal 20 mm and height 20 mm), reflector materials and shapes, optical contact and surface properties (polished and diffused) were measured. The crystal scintillator of hexagonal shape shows the better energy resolution and pulse amplitude. The best energy resolution (FWHM = 9.3 % for 662 keV γ quanta of 137 Cs) was obtained with a hexagonal scintillator with all surfaces diffuse, in optical contact with a PMT and surrounded by a reflector (3M) of size 26x25 mm. In the geometry w ithout optical contact r epresenting the conditions of light collection for a cryogenic scintillating bolometer the best energy resolution and relative pulse amplitude was obtained for a hexagonal shape scintillator with diffuse side and polished face surfaces, surrounded by a reflector with a gap between the scintillator and the reflector

  19. Performance comparison of scintillators for alpha particle detectors

    Energy Technology Data Exchange (ETDEWEB)

    Morishita, Yuki [Graduate School of Medicine, Nagoya University, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya, Aichi 461-8673 (Japan); Japan Atomic Energy Agency, Muramatsu 4-33, Tokai-mura, Ibaraki 319-1194 (Japan); Yamamoto, Seiichi [Graduate School of Medicine, Nagoya University, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya, Aichi 461-8673 (Japan); Izaki, Kenji [Japan Atomic Energy Agency, Muramatsu 4-33, Tokai-mura, Ibaraki 319-1194 (Japan); Kaneko, Junichi H.; Toui, Kohei; Tsubota, Youichi; Higuchi, Mikio [Graduate School of Engineering, Hokkaido University, Kita 13, Nishi 8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan)

    2014-11-11

    Scintillation detectors for alpha particles are often used in nuclear fuel facilities. Alpha particle detectors have also become important in the research field of radionuclide therapy using alpha emitters. ZnS(Ag) is the most often used scintillator for alpha particle detectors because its light output is high. However, the energy resolution of ZnS(Ag)-based scintillation detectors is poor because they are not transparent. A new ceramic sample, namely the cerium doped Gd{sub 2}Si{sub 2}O{sub 7} (GPS) scintillator, has been tested as alpha particle detector and its performances have been compared to that one of three different scintillating materials: ZnS(Ag), GAGG and a standard plastic scintillator. The different scintillating materials have been coupled to two different photodetectors, namely a photomultiplier tube (PMT) and a Silicon Photo-multiplier (Si-PM): the performances of each detection system have been compared. Promising results as far as the energy resolution performances (10% with PMT and 14% with Si-PM) have been obtained in the case of GPS and GAGG samples. Considering the quantum efficiencies of the photodetectors under test and their relation to the emission wavelength of the different scintillators, the best results were achieved coupling the GPS with the PMT and the GAGG with the Si-PM.

  20. Structured scintillators for X-ray imaging with micrometre resolution

    DEFF Research Database (Denmark)

    Olsen, Ulrik Lund; Schmidt, Søren; Poulsen, Henning Friis

    2009-01-01

    A 3D X-ray detector for imaging of 30–200 keV photons is described. It comprises a stack of semitransparent structured scintillators, where each scintillator is a regular array of waveguides in silicon, and with pores filled with CsI. The performance of the detector is described theoretically...

  1. Scintillator quenching effects observed in the AMS-1 TOF data

    Science.gov (United States)

    Esquivel, O.; Reyes, T.; Menchaca-Rocha, A.

    2001-05-01

    An analytical expression for the light output response of plastic scintillators as a function of the energy and the z identity of the incident ion is proposed. The effect of the δ rays is considered in the calculation of the scintillation efficiency. .

  2. Radiation damage studies on polystyrene-based scintillators

    International Nuclear Information System (INIS)

    Britvich, G.I.; Peresypkin, A.I.; Rykalin, V.I.

    1991-01-01

    The radiation resistance of polystyrene-based scintillators containing various scintillation dopes is reported. All samples were irradiated to 137 Cs gamma rays in air at room temperature. The examination of radiation resistance of about thirty fluorescence compounds has been made. The most radiation-hard fluores are X25, X31, 3HF and M3HF. 1 fig.; 6 tabs

  3. Systematic studies of small scintillators for new sampling calorimeter

    Indian Academy of Sciences (India)

    A new sampling calorimeter using very thin scintillators and the multi-pixel photon counter (MPPC) has been proposed to produce better position resolution for the international linear collider (ILC) experiment. As part of this R & D study, small plastic scintillators of different sizes, thickness and wrapping reflectors are ...

  4. Performance evaluation of GPS receiver under equatorial scintillation

    Directory of Open Access Journals (Sweden)

    Alison de Oliveira Moraes

    2009-06-01

    Full Text Available Equatorial scintillation is a phenomenon that occurs daily in the equatorial region after the sunset and affects radio signals that propagate through the ionosphere. Depending on the temporal and spatial situation, equatorial scintillation can represent a problem in the availability and precision of the Global Positioning System (GPS. This work is concerned with evaluating the impact of equatorial scintillation on the performance of GPS receivers. First, the morphology and statistical model of equatorial scintillation is briefly presented. A numerical model that generates synthetic scintillation data to simulate the effects of equatorial scintillation is presented. An overview of the main theoretical principles on GPS receivers is presented. The analytical models that describe the effects of scintillation at receiver level are presented and compared with numerical simulations using a radio software receiver and synthetic data. The results achieved by simulation agreed quite well with those predicted by the analytical models. The only exception is for links with extreme levels of scintillation and when weak signals are received.

  5. Some history of liquid scintillator development at Los Alamos

    International Nuclear Information System (INIS)

    Ott, D.G.

    1979-01-01

    The early developments in liquid scintillation counting made at Los Alamos Scientific Laboratory are reviewed. Most of the work was under the direction of F.N. Hayes and included counter development and applications as well as synthesis and chemistry of liquid scintillators

  6. Neutron-gamma discrimination of boron loaded plastic scintillator

    International Nuclear Information System (INIS)

    Wang Dong; He Bin; Zhang Quanhu; Wu Chuangxin; Luo Zhonghui

    2010-01-01

    Boron loaded plastic scintillator could detect both fast neutrons thanks to hydrogen and thermal neutrons thanks to 10B. Both reactions have large cross sections, and results in high detection efficiency of incident neutrons. However, similar with other organic scintillators, boron loaded plastic scintillator is sensitive to gamma rays and neutrons. So gamma rays must be rejected from neutrons using their different behavior in the scintillator. In the present research zero crossing method was used to test neutron-gamma discrimination of BC454 boron loaded plastic scintillator. There are three Gaussian peaks in the time spectrum, they are corresponding to gamma rays, fast neutrons and flow neutrons respectively. Conclusion could be made that BC454 could clear discriminate slow neutrons and gamma, but the discrimination performance turns poor as the neutrons' energy becomes larger. (authors)

  7. Scintillating fiber detector development for the SSC: Annual progress report

    International Nuclear Information System (INIS)

    Ruchti, R.C.

    1989-01-01

    During the past year, considerable effort has been applied to the development of scintillating fiber detectors in several areas: new scintillation liquids and studies of their fluorescence properties; new fluorescent dyes based on non-intramolecular proton transfer; new dyes based on intramolecular proton transfer; incorporation of these new dyes in plastic (polystyrene) and liquid scintillation solutions; development of small cross section glass capillaries for the containment of liquid scintillators; studies of waveguide characteristics; studies of image intensifier phosphor screen characteristics; initial steps to form a collaboration to study and develop appropriate new properties of the Solid State Photomultiplier; construction of a new laboratory at Notre Dame to enhance our capabilities for further measurements and studies; and organization of and execution of a Workshop on Scintillating Fiber Detector Development for the SSC, held at Fermilab, November 14--16, 1988

  8. The use of energy information in plastic scintillator materia

    International Nuclear Information System (INIS)

    Ely, J.; Anderson, K.; Bates, D.; Kouzes, R.; Lo Presti, C.; Runkle, R.; Siciliano, E.; Weier, D.

    2008-01-01

    Plastic scintillator material is often used for gamma-ray detection in many applications due to its relatively good sensitivity and cost-effectiveness compared to other detection materials. However, due to the dominant Compton scattering interaction mechanism, full energy peaks are not observed in plastic scintillator spectra and isotopic identification is impossible. Typically plastic scintillator detectors are solely gross count detectors. In some safeguards and security applications, such as radiation portal monitors for vehicle screening, naturally-occurring radioactive material (NORM) often triggers radiation alarms and results in innocent or nuisance alarms. The limited energy information from plastic scintillator material can be used to discriminate the NORM from targeted materials and reduce the nuisance alarm rate. An overview of the utilization of the energy information from plastic scintillator material will be presented, with emphasis on the detection capabilities and potential limitations for safeguards and security applications. (author)

  9. The primary research for the development of the plastic scintillator

    International Nuclear Information System (INIS)

    Huang Bing; Li Wei; Yang Yan

    2014-01-01

    In this study, We adopted the theory of the polymerism to synthesize the scintillator, and we composed the scintillating material (2, 5-diphenyloxazole (PPO) and 1, 4-bis-(2-(5-phenyloxazolyl))-benzene (POPOP)) to the plastic (PMMA) successfully by the polymerization. We found that the scintillating material (PPO and POPOP) spread well into the plastic and the scintillator could be well seasoned with many different environmental condition through the spectroanalysis and the mechanical testing. We also found that the scintillator was well responded to the γ-ray testing which we did. According to the increase of the content for the PPO, the radiant efficiency of the γ-ray testing was increase too. (authors)

  10. Lanthanum halide scintillators: Properties and applications

    International Nuclear Information System (INIS)

    Iltis, Alain; Mayhugh, M.R.; Menge, P.; Rozsa, C.M.; Selles, O.; Solovyev, V.

    2006-01-01

    BrilLanCe[reg]-350 and BrilLanCe[reg]-380, Saint-Gobain Crystals' trade-names for LaCl 3 :Ce and LaBr 3 :Ce are being brought to market under exclusive license to Delft and Bern Universities. We are reporting the properties of crystals produced with commercially viable processes and find they match others' observations. These scintillators are bright (60,000 photons/MeV for LaBr 3 :Ce) and have very linear response, a combination that leads to very good energy resolution ( 3 :Ce). The materials also have fast scintillation decay times ( 3 :Ce). These excellent properties are retained at high temperature with only moderate light loss ( 138 and Ac 227 , the latter having been substantially reduced in recent processing. BrilLanCe[reg]-350 is now available in detectors up to 51 mm diameter while 38 mm diameter is available for BrilLanCe[reg]-380. Larger sizes are expected

  11. Buried plastic scintillator muon telescope (BATATA)

    International Nuclear Information System (INIS)

    Alfaro, R.; De Donato, C.; D'Olivo, J.C.; Guzman, A.; Medina-Tanco, G.; Moreno Barbosa, E.; Paic, G.; Patino Salazar, E.; Salazar Ibarguen, H.; Sanchez, F.A.; Supanitsky, A.D.; Valdes-Galicia, J.F.; Vargas Trevino, A.D.; Vergara Limon, S.; Villasenor, L.M.

    2010-01-01

    Muon telescopes have multiple applications in the area of cosmic ray research. We are currently building such a detector with the objective of comparing the ground penetration of muon vs. electron-gamma signals originated in cosmic ray showers. The detector is composed by a set of three parallel dual-layer scintillator planes, buried at fixed depths ranging from 120 to 600g/cm 2 . Each layer is 4m 2 and is composed by 49 rectangular strips of 4cmx2m, oriented at a 90 0 angle with respect to its companion layer, which gives an xy-coincidence pixel of 4x4cm 2 . The scintillators are MINOS extruded polystyrene strips, with an embedded Bicron BC92 wavelength shifting (WLS) fibers, of 1.5 mm in diameter. Light is collected by Hamamatsu H7546B multi-anode PMTs of 64 pixels. The front-end (FE) electronics works in counting mode and signals are transmitted to the surface DAQ stage using low-voltage differential signaling (LVDS). Any strip signal above threshold opens a GPS-tagged 2μs data collection window. Data, including signal and background, are acquired by a system of FPGA (Spartan 2E) boards and a single-board computer (TS7800).

  12. Tracking heliospheric disturbances by interplanetary scintillation

    Directory of Open Access Journals (Sweden)

    M. Tokumaru

    2006-01-01

    Full Text Available Coronal mass ejections are known as a solar cause of significant geospace disturbances, and a fuller elucidation of their physical properties and propagation dynamics is needed for space weather predictions. The scintillation of cosmic radio sources caused by turbulence in the solar wind (interplanetary scintillation; IPS serves as an effective ground-based method for monitoring disturbances in the heliosphere. We studied global properties of transient solar wind streams driven by CMEs using 327-MHz IPS observations of the Solar-Terrestrial Environment Laboratory (STEL of Nagoya University. In this study, we reconstructed three-dimensional features of the interplanetary (IP counterpart of the CME from the IPS data by applying the model fitting technique. As a result, loop-shaped density enhancements were deduced for some CME events, whereas shell-shaped high-density regions were observed for the other events. In addition, CME speeds were found to evolve significantly during the propagation between the corona and 1 AU.

  13. Buried plastic scintillator muon telescope (BATATA)

    Energy Technology Data Exchange (ETDEWEB)

    Alfaro, R. [Inst. de Fisica, Universidad Nacional Autonoma de Mexico, Mexico, D.F., C.P. 04510 (Mexico); De Donato, C.; D' Olivo, J.C.; Guzman, A.; Medina-Tanco, G. [Inst. de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Mexico, D.F., C.P. 04510 (Mexico); Moreno Barbosa, E. [Fac. de Ciencias Fisico Matematicas, Benemerita Universidad Autonoma de Puebla, Puebla (Mexico); Paic, G.; Patino Salazar, E. [Inst. de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Mexico, D.F., C.P. 04510 (Mexico); Salazar Ibarguen, H. [Fac. de Ciencias Fisico Matematicas, Benemerita Universidad Autonoma de Puebla, Puebla (Mexico); Sanchez, F.A., E-mail: federico.sanchez@nucleares.unam.m [Inst. de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Mexico, D.F., C.P. 04510 (Mexico); Supanitsky, A.D. [Inst. de Ciencias Nucleares, Universidad Nacional Autonoma de Mexico, Mexico, D.F., C.P. 04510 (Mexico); Valdes-Galicia, J.F. [Inst. de Geofisica, Universidad Nacional Autonoma de Mexico, Mexico, D.F., C.P. 04510 (Mexico); Vargas Trevino, A.D.; Vergara Limon, S. [Fac. de Ciencias de la Electronica, Benemerita Universidad Autonoma de Puebla, Puebla (Mexico); Villasenor, L.M. [Inst. de Fisica y Matematicas, Universidad Michoacana de San Nicolas Hidalgo Morelia (Mexico); Observatorio Pierre Auger, Av. San Martin Norte 304 (5613) Malarguee, Prov. Mendoza (Argentina)

    2010-05-21

    Muon telescopes have multiple applications in the area of cosmic ray research. We are currently building such a detector with the objective of comparing the ground penetration of muon vs. electron-gamma signals originated in cosmic ray showers. The detector is composed by a set of three parallel dual-layer scintillator planes, buried at fixed depths ranging from 120 to 600g/cm{sup 2}. Each layer is 4m{sup 2} and is composed by 49 rectangular strips of 4cmx2m, oriented at a 90{sup 0} angle with respect to its companion layer, which gives an xy-coincidence pixel of 4x4cm{sup 2}. The scintillators are MINOS extruded polystyrene strips, with an embedded Bicron BC92 wavelength shifting (WLS) fibers, of 1.5 mm in diameter. Light is collected by Hamamatsu H7546B multi-anode PMTs of 64 pixels. The front-end (FE) electronics works in counting mode and signals are transmitted to the surface DAQ stage using low-voltage differential signaling (LVDS). Any strip signal above threshold opens a GPS-tagged 2{mu}s data collection window. Data, including signal and background, are acquired by a system of FPGA (Spartan 2E) boards and a single-board computer (TS7800).

  14. Pulse widths effects on scintillator saturation

    International Nuclear Information System (INIS)

    Kohler, D.A.; Chase, L.F.

    1978-08-01

    A test was performed over an extensive range of irrradiance (approximately five orders of magnitude) to see to what extent organic scintillators responded linearly with x-ray input. At the highest levels of irradiance achievable with the experimental configuration, but only for pulses in the region of 4.0 ns or wider, a degree of nonlinear response was observed for some of the scintillators. The data suggest that at levels below 1 mJ/cm 2 -ns it is safe to asume that for pulses 6.5 ns and shorter there is no significant level of nonlinearity to x rays with spectrum. For the cases of undoped NE111 and NE111 doped with 10 percent benzophenone, experimental conditions were such that it was possible to accumulate data significantly above the 1 mJ/cm 2 -ns level of irradiance. It is with these cases that a nonlinear response was observed. It is assumed that the same nonlinearity would have also been noticed had experimental conditions been such that equivalent levels of irradiance could have been achieved at the time the other samples were studied

  15. Semiconductor scintillator detector for gamma radiation

    International Nuclear Information System (INIS)

    Laan, F.T.V. der; Borges, V.; Zabadal, J.R.S.

    2015-01-01

    Nowadays the devices employed to evaluate individual radiation exposition are based on dosimetric films and thermoluminescent crystals, whose measurements must be processed in specific transductors. Hence, these devices carry out indirect measurements. Although a new generation of detectors based on semiconductors which are employed in EPD's (Electronic Personal Dosemeters) being yet available, it high producing costs and large dimensions prevents the application in personal dosimetry. Recent research works reports the development of new detection devices based on photovoltaic PIN diodes, which were successfully employed for detecting and monitoring exposition to X rays. In this work, we step forward by coupling a 2mm anthracene scintillator NE1, which converts the high energy radiation in visible light, generating a Strong signal which allows dispensing the use of photomultipliers. A low gain high performance amplifier and a digital acquisition device are employed to measure instantaneous and cumulative doses for energies ranging from X rays to Gamma radiation up to 2 MeV. One of the most important features of the PIN diode relies in the fact that it can be employed as a detector for ionization radiation, since it requires a small energy amount for releasing electrons. Since the photodiode does not amplify the corresponding photon current, it must be coupled to a low gain amplifier. Therefore, the new sensor works as a scintillator coupled with a photodiode PIN. Preliminary experiments are being performed with this sensor, showing good results for a wide range of energy spectrum. (author)

  16. Search for missing baryons through scintillation

    International Nuclear Information System (INIS)

    Habibi, F.

    2011-06-01

    Cool molecular hydrogen H 2 may be the ultimate possible constituent to the Milky-Way missing baryon. We describe a new way to search for such transparent matter in the Galactic disc and halo, through the diffractive and refractive effects on the light of background stars. By simulating the phase delay induced by a turbulent medium, we computed the corresponding illumination pattern on the earth for an extended source and a given passband. We show that in favorable cases, the light of a background star can be subjected to stochastic fluctuations of the order of a few percent at a characteristic time scale of a few minutes. We have searched for scintillation induced by molecular gas in visible dark nebulae as well as by hypothetical halo clumpuscules of cool molecular hydrogen (H 2 -He) during two nights, using the NTT telescope and the IR SOFI detector. Amongst a few thousands of monitored stars, we found one light-curve that is compatible with a strong scintillation effect through a turbulent structure in the B68 nebula. Because no candidate were found toward the SMC (Small Magellan Cloud), we are able to establish upper limits on the contribution of gas clumpuscules to the Galactic halo mass. We show that the short time-scale monitoring of a few 10 6 star*hour in the visible band with a >4 m telescope and a fast readout camera should allow one to interestingly quantify or constrain the contribution of turbulent molecular gas to the Galactic halo. (author)

  17. Data process of liquid scintillation counting

    International Nuclear Information System (INIS)

    Ishikawa, Hiroaki; Kuwajima, Susumu.

    1975-01-01

    The use of liquid scintillation counting system has been significantly spread because automatic sample changers and printers have recently come to be incorporated. However, the system will be systematized completely if automatic data processing and the sample preparation of radioactive materials to be measured are realized. Dry or wet oxidation method is applied to the sample preparation when radioactive materials are hard to dissolve into scintillator solution. Since these several years, the automatic sample combustion system, in which the dry oxidation is automated, has been rapidly spread and serves greatly to labor saving. Since the printers generally indicate only counted number, data processing system has been developed, and speeded up calculating process, which automatically corrects quenching of samples for obtaining the final radioactivity required. The data processing system is roughly divided into on-line and off-line systems according to whether computers are connected directly or indirectly, while its hardware is classified to input, calculating and output devices. Also, the calculation to determine sample activity by external standard method is explained. (Wakatsuki, Y.)

  18. Collimator trans-axial tomographic scintillation camera

    International Nuclear Information System (INIS)

    Jaszczak, Ronald J.

    1979-01-01

    An improved collimator is provided for a scintillation camera system that employs a detector head for transaxial tomographic scanning. One object of this invention is to significantly reduce the time required to obtain statistically significant data in radioisotope scanning using a scintillation camera. Another is to increase the rate of acceptance of radioactive events to contribute to the positional information obtainable from a radiation source of known strength without sacrificing spatial resolution. A further object is to reduce the necessary scanning time without degrading the images obtained. The collimator described has apertures defined by septa of different radiation transparency. The septa are aligned to provide greater radiation shielding from gamma radiation travelling within planes perpendicular to the cranial-caudal axis and less radiation shielding from gamma radiation travelling within other planes. Septa may also define apertures such that the collimator provides high spatial resolution of gamma rays traveling within planes perpendicular to the cranial-caudal axis and directed at the detector and high radiation sensitivity to gamma radiation travelling other planes and indicated at the detector. (LL)

  19. Liquid Scintillation Detectors for High Energy Neutrinos

    International Nuclear Information System (INIS)

    Smith, Stefanie N.; Learned, John G.

    2010-01-01

    Large open volume (not segmented) liquid scintillation detectors have been generally dedicated to low energy neutrino measurements, in the MeV energy region. We describe the potential employment of large detectors (>1 kiloton) for studies of higher energy neutrino interactions, such as cosmic rays and long-baseline experiments. When considering the physics potential of new large instruments the possibility of doing useful measurements with higher energy neutrino interactions has been overlooked. Here we take into account Fermat's principle, which states that the first light to reach each PMT will follow the shortest path between that PMT and the point of origin. We describe the geometry of this process, and the resulting wavefront, which we are calling the 'Fermat surface', and discuss methods of using this surface to extract directional track information and particle identification. This capability may be demonstrated in the new long-baseline neutrino beam from Jaeri accelerator to the KamLAND detector in Japan. Other exciting applications include the use of Hanohano as a movable long-baseline detector in this same beam, and LENA in Europe for future long-baseline neutrino beams from CERN. Also, this methodology opens up the question as to whether a large liquid scintillator detector should be given consideration for use in a future long-baseline experiment from Fermilab to the DUSEL underground laboratory at Homestake.

  20. Effect of subcritical CO{sub 2} on ionic conductivity of (Al[O(CH{sub 2}CH{sub 2}O){sub 8.7}]{sub r}/(LiClO{sub 4}){sub z}){sub n} hybrid inorganic-organic networks

    Energy Technology Data Exchange (ETDEWEB)

    Vezzu, Keti; Bertucco, Alberto [Universita di Padova, Padova (Italy). Dipartimento di Principi e Impianti di Ingegneria Chimica ' I. Sorgato' ; Zago, Vanni; Vittadello, Michele; Noto, Vito Di [Universita di Padova, Padova (Italy). Dipartimento di Scienze Chimiche

    2006-01-20

    The aim of this work is to study the effect of CO{sub 2} under pressure on hybrid inorganic-organic polymer electrolytes, by using broad band dielectric spectroscopy (BDS) in the frequency interval 40Hz-10MHz and in the temperature range of -80 to 120{sup o}C. Eleven inorganic-organic hybrid materials of the ORMOCERs type, with general formula (Al[O(CH{sub 2}CH{sub 2}O){sub 8.7}]{sub r}/(LiClO{sub 4}){sub z}){sub n} were treated by applying CO{sub 2} at 293K and 5MPa. The results demonstrated that the CO{sub 2} treatment generally depressed the conductivity of about one order of magnitude. The decreased conductivity in treated complexes is explained in terms of a smaller anion-trapping ability of the Al centers. Residual CO{sub 2} molecules are likely to inhibit the interaction of the perchlorate anions with Al centers within the structure. Segmental motion of the polymer chains plays a crucial role in the conductivity of investigated samples, while the ion-hopping phenomenon is the most important charge transfer mechanism both in the pristine and CO{sub 2} treated materials. Equivalent conductivity studies have elucidated the different ionic species present at various salt concentrations and gave insight about the role of CO{sub 2} in modifying the transport properties of the samples. (author)

  1. Scintillation densimeter for liquids and an isotopic conveyor weighers with plastic scintillator

    International Nuclear Information System (INIS)

    Makhaj, B.; Antonyak, V.; Plyater, Z.

    1979-01-01

    The method is described of the weighted material's mass measuring according to the results of the conveyor momentary load measurement derived from the attenuation of radiation in the transmission geometry, conveyor belt velocity measurement and digital processing of the signals from the measurement of the bouth values. In the measuring gage there are located: the point type gamma source of cesium-137 with 4 mCi capacity, the scintillation detector with plastic cylindric scintillator of 5 cm in diameter and with the length approximately equal to the width of the conveyor belt and also the tachometer-generator. The conveyor weighers described is intended for use with conveyor having belt; from 60 to 180 cm wide. The results are given of industrial exploitation of the instrument [ru

  2. Scintillation properties of transparent ceramic and single crystalline Nd:YAG scintillators

    International Nuclear Information System (INIS)

    Yanagida, Takayuki; Kamada, Kei; Fujimoto, Yutaka; Yokota, Yuui; Yoshikawa, Akira; Yagi, Hideki; Yanagitani, Takagimi

    2011-01-01

    Nd 0.1, 1.1, 2, 4, and 6 mol% doped YAG transparent ceramics are manufactured by the sintering method and their scintillation properties are compared with those of single crystalline Nd 1 mol% doped YAG grown by the micro-pulling down method. They show ∼80% transmittance at wavelengths longer than 300 nm and strong emission lines due to Nd 3+ 4f-4f emission in their radio-luminescence spectra. Among them, the single crystalline sample shows the highest light yield of 11,000 ph/MeV under γ-ray excitation and the second highest one is from Nd 1.1 mol% doped transparent ceramic, which shows 6000 ph/MeV. In these scintillators, dominant decay time constant is around 2-3 μs due to Nd 3+ 4f-4f transitions.

  3. Scintillation properties of transparent ceramic and single crystalline Nd:YAG scintillators

    Energy Technology Data Exchange (ETDEWEB)

    Yanagida, Takayuki, E-mail: t_yanagi@tagen.tohoku.ac.j [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Kamada, Kei; Fujimoto, Yutaka; Yokota, Yuui [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); Yoshikawa, Akira [Institute of Multidisciplinary Research for Advanced Materials, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577 (Japan); New Industry Creation Hatchery Center (NICHe), Tohoku University, 6-6-10 Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Yagi, Hideki; Yanagitani, Takagimi [Konoshima Chemical Co., Ltd., 80 Kouda, Takuma, Mitoyo-gun, Kagawa 769-1103 (Japan)

    2011-03-01

    Nd 0.1, 1.1, 2, 4, and 6 mol% doped YAG transparent ceramics are manufactured by the sintering method and their scintillation properties are compared with those of single crystalline Nd 1 mol% doped YAG grown by the micro-pulling down method. They show {approx}80% transmittance at wavelengths longer than 300 nm and strong emission lines due to Nd{sup 3+} 4f-4f emission in their radio-luminescence spectra. Among them, the single crystalline sample shows the highest light yield of 11,000 ph/MeV under {gamma}-ray excitation and the second highest one is from Nd 1.1 mol% doped transparent ceramic, which shows 6000 ph/MeV. In these scintillators, dominant decay time constant is around 2-3 {mu}s due to Nd{sup 3+} 4f-4f transitions.

  4. Development of scintillation materials for medical imaging and other applications

    International Nuclear Information System (INIS)

    Melcher, C. L.

    2013-01-01

    Scintillation materials that produce pulses of visible light in response to the absorption of energetic photons, neutrons, and charged particles, are widely used in various applications that require the detection of radiation. The discovery and development of new scintillators has accelerated in recent years, due in large part to their importance in medical imaging as well as in security and high energy physics applications. Better understanding of fundamental scintillation mechanisms as well as the roles played by defects and impurities have aided the development of new high performance scintillators for both gamma-ray and neutron detection. Although single crystals continue to dominate gamma-ray based imaging techniques, composite materials and transparent optical ceramics potentially offer advantages in terms of both synthesis processes and scintillation performance. A number of promising scintillator candidates have been identified during the last few years, and several are currently being actively developed for commercial production. Purification and control of raw materials and cost effective crystal growth processes can present significant challenges to the development of practical new scintillation materials.

  5. Cerium doped lanthanum halides: fast scintillators for medical imaging

    International Nuclear Information System (INIS)

    Selles, O.

    2006-12-01

    This work is dedicated to two recently discovered scintillating crystals: cerium doped lanthanum halides (LaCl 3 :Ce 3+ and LaBr 3 :Ce 3+ ).These scintillators exhibit interesting properties for gamma detection, more particularly in the field of medical imaging: a short decay time, a high light yield and an excellent energy resolution. The strong hygroscopicity of these materials requires adapting the usual experimental methods for determining physico-chemical properties. Once determined, these can be used for the development of the industrial manufacturing process of the crystals. A proper comprehension of the scintillation mechanism and of the effect of defects within the material lead to new possible ways for optimizing the scintillator performance. Therefore, different techniques are used (EPR, radioluminescence, laser excitation, thermally stimulated luminescence). Alongside Ce 3+ ions, self-trapped excitons are involved in the scintillation mechanism. Their nature and their role are detailed. The knowledge of the different processes involved in the scintillation mechanism leads to the prediction of the effect of temperature and doping level on the performance of the scintillator. A mechanism is proposed to explain the thermally stimulated luminescence processes that cause slow components in the light emission and a loss of light yield. Eventually the study of afterglow reveals a charge transfer to deep traps involved in the high temperature thermally stimulated luminescence. (author)

  6. Study of the correlation of scintillation decay and emission wavelength

    International Nuclear Information System (INIS)

    Yanagida, Takayuki; Fujimoto, Yutaka; Yamaji, Akihiro; Kawaguchi, Noriaki; Kamada, Kei; Totsuka, Daisuke; Fukuda, Kentaro; Yamanoi, Kohei; Nishi, Ryosuke; Kurosawa, Shunsuke; Shimizu, Toshihiko; Sarukura, Nobuhiko

    2013-01-01

    In photoluminescence which directly excites the emission center of phosphor material is known to have a correlation between the emission wavelength and the decay time based on quantum mechanics. In scintillation phenomenon, host lattice of the material is first excited by ionizing radiation and then the excitation energy is transferred to emission centers. For the first time, we investigated the correlation between the scintillation decay and the emission wavelength by using pulse X-ray equipped streak camera system which could observe time and wavelength resolved scintillation phenomenon. Investigated materials were Ce 3+ , Pr 3+ and Nd 3+ doped oxides and fluorides which all showed 5d-4f transition based emission. As a result, we obtained the relation that τ (scintillation decay time) was proportional to the λ 2.15 (emission wavelength). -- Highlights: ► The correlation between emission wavelength and scintillation decay time is investigated. ► Photoluminescence decay times are also evaluated and compared with scintillation decay times. ► It is proved the relaxation process in emission center is dominant even in scintillation decay

  7. Scintillation characteristics of LiPO3:Ce3+ glass scintillators

    International Nuclear Information System (INIS)

    Shin, S. W.; Hwang, J. H.

    2003-01-01

    LiPO 3 :Ce 3+ glass scintillators doped with 0.5, 0.75, 1.0, 1.25 and 1.5wt% cerium as an activator were fabricated. For the best transparency of the LiPO 3 glasses, optimum heating conditions were investigated. Optimum heating temperature and time is 950 .deg. C and 90 min with 1wt% sugar add as reductant. The lattice structure of LiPO 3 :Ce 3+ glass scintillator was monoclinic, its lattice constants(a 0 , b 0 , c 0 ) being 16,490λ, 5.427λ and 13.120λ. Photo-refraction index of LiPO 3 :Ce 3 + measured by SE(Spectroscopic ellipsometry) was 1.45 ∼ 1.5 and its bandgap energy was 2.342 eV. The absorption spectral range of LiPO 3 :Ce 3+ measured by UV-VIS spectrophotometry was 350∼ 375nm and the spectral ranges of photoluminescence(PL) were 400∼450nm and 750∼900nm, its maximum PL intensity appeared at 417nm and 791nm. LiPO 3 :Ce 3 + glass scintillator doped with 0.75wt% cerium showed the best PL intensity. The PL intensity increased until cerium content reaches 0.75wt% above which ir decreased

  8. Monte Carlo simulation of electron thermalization in scintillator materials: Implications for scintillator nonproportionality

    Energy Technology Data Exchange (ETDEWEB)

    Prange, Micah P. [Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA; Xie, YuLong [Energy and Environment Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA; Campbell, Luke W. [National Security Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA; Gao, Fei [Department of Nuclear Engineering and Radiological Sciences, University of Michigan, Ann Arbor, Michigan 48109, USA; Kerisit, Sebastien [Physical and Computational Sciences Directorate, Pacific Northwest National Laboratory, Richland, Washington 99352, USA

    2017-12-21

    The lack of reliable quantitative estimates of the length and time scales associated with hot electron thermalization after a gamma-ray induced energy cascade obscures the interplay of various microscopic processes controlling scintillator performance and hampers the search for improved detector materials. We apply a detailed microscopic kinetic Monte Carlo model of the creation and subsequent thermalization of hot electrons produced by gamma irradiation of six important scintillating crystals to determine the spatial extent of the cloud of excitations produced by gamma rays and the time required for the cloud to thermalize with the host lattice. The main ingredients of the model are ensembles of microscopic track structures produced upon gamma excitation (including the energy distribution of the excited carriers), numerical estimates of electron-phonon scattering rates, and a calculated particle dispersion to relate the speed and energy of excited carriers. All these ingredients are based on first-principles density functional theory calculations of the electronic and phonon band structures of the materials. Details of the Monte Carlo model are presented along with results for thermalization time and distance distributions. These results are discussed in light of previous work. It is found that among the studied materials, calculated thermalization distances are positively correlated with measured nonproportionality. In the important class of halide scintillators, the particle dispersion is found to be more influential than the largest phonon energy in determining the thermalization distance.

  9. Comparison of plastic scintillating fibres and capillaries filled with liquid scintillator

    International Nuclear Information System (INIS)

    Cardini, A.; Cavasinni, V.; Girolamo, B. di; Flaminio, V.; Golovkin, S.V.; Gorin, A.M.; Kulichenko, A.V.; Kushnirenko, A.E.; Pyshev, A.I.; Manuilov, I.; Vasilchenko, V.G.

    1994-01-01

    A comparison is made between the light yield, attenuation length, time response and light propagation speed in plastic scintillating fibres (SCSF-38 and Kuraray-3HF) and quartz capillaries filled with liquid scintillator (LS) 1-methilnaphthalene (1MN) doped with new dyes R45 and R39. The inner diameter of capillaries and diameter of plastic fibres is 0.5 mm. The number of photoelectrons detected at the far end (2 m) was 2.9 for capillaries filled with 1MN+3 g/l R45 while it was 1.8 times smaller in the case of SCSF-38 and 3 times smaller in the case of Kuraray 3HF plastic fibres. Taking into account the quantum efficiency of the photodetector used these reduction factors became 3.0 and 2.0, respectively. Good attenuation length, high light output and also excellent radiation resistance of capillaries filled with LS (>60 Mrad, measured elsewhere) show that they are a very promising alternative to plastic scintillating fibres for future applications in tracking detectors and calorimeters. ((orig.))

  10. Surface preparation and coupling in plastic scintillator dosimetry

    International Nuclear Information System (INIS)

    Ayotte, Guylaine; Archambault, Louis; Gingras, Luc; Lacroix, Frederic; Beddar, A. Sam; Beaulieu, Luc

    2006-01-01

    One way to improve the performance of scintillation dosimeters is to increase the light-collection efficiency at the coupling interfaces of the detector system. We performed a detailed study of surface preparation of scintillating fibers and their coupling with clear optical fibers to minimize light loss and increase the amount of light collected. We analyzed fiber-surface polishing with aluminum oxide sheets, coating fibers with magnesium oxide, and the use of eight different coupling agents (air, three optical gels, an optical curing agent, ultraviolet light, cyanoacrylate glue, and acetone). We prepared 10 scintillating fiber and clear optical fiber light guide samples to test different coupling methods. To test the coupling, we first cut both the scintillating fiber and the clear optical fiber. Then, we cleaned and polished both ends of both fibers. Finally, we coupled the scintillating fiber with the clear optical fiber in either a polyethylene jacket or a V-grooved support depending on the coupling agent used. To produce more light, we used an ultraviolet lamp to stimulate scintillation. A typical series of similar couplings showed a standard deviation in light-collection efficiency of 10%. This can be explained by differences in the surface preparation quality and alignment of the scintillating fiber with the clear optical fiber. Absence of surface polishing reduced the light collection by approximately 40%, and application of magnesium oxide on the proximal end of the scintillating fiber increased the amount of light collected from the optical fiber by approximately 39%. Of the coupling agents, we obtained the best results using one of the optical gels. Because a large amount of the light produced inside a scintillator is usually lost, better light-collection efficiency will result in improved sensitivity

  11. Multi-view collimators for scintillation cameras

    International Nuclear Information System (INIS)

    Hatton, J.; Grenier, R.P.

    1982-01-01

    This patent specification describes a collimator for obtaining multiple images of a portion of a body with a scintillation camera comprises a body of radiation-impervious material defining two or more groups of channels each group comprising a plurality of parallel channels having axes intersecting the portion of the body being viewed on one side of the collimator and intersecting the input surface of the camera on the other side of the collimator to produce a single view of said body, a number of different such views of said body being provided by each of said groups of channels, each axis of each channel lying in a plane approximately perpendicular to the plane of the input surface of the camera and all of such planes containing said axes being approximately parallel to each other. (author)

  12. Collimated trans-axial tomographic scintillation camera

    International Nuclear Information System (INIS)

    1980-01-01

    The principal problem in trans-axial tomographic radioisotope scanning is the length of time required to obtain meaningful data. Patient movement and radioisotope migration during the scanning period can cause distortion of the image. The object of this invention is to reduce the scanning time without degrading the images obtained. A system is described in which a scintillation camera detector is moved to an orbit about the cranial-caudal axis relative to the patient. A collimator is used in which lead septa are arranged so as to admit gamma rays travelling perpendicular to this axis with high spatial resolution and those travelling in the direction of the axis with low spatial resolution, thus increasing the rate of acceptance of radioactive events to contribute to the positional information obtainable without sacrificing spatial resolution. (author)

  13. High-Z organic-scintillation solution

    International Nuclear Information System (INIS)

    Berlman, I.B.; Fluornoy, J.M.; Ashford, C.B.; Lyons, P.B.

    1983-01-01

    In the present experiment, an attempt is made to raise the average Z of a scintillation solution with as little attendant quenching as possible. Since high-Z atoms quench by means of a close encounter, such encounters are minimized by the use of alkyl groups substituted on the solvent, solute, and heavy atoms. The aromatic compound 1,2,4-trimethylbenzene (pseudocumene) is used as the solvent; 4,4''-di(5-tridecyl)-p-terphenyl (SC-180) as the solute; and tetrabutyltin as the high-Z material. To establish the validity of our ideas, various experiments have been performed with less protected solvents, and heavy atoms. These include benzene, toluene, p-terphenyl, bromobutane, and bromobenzene

  14. Elevator mechanism and method for scintillation detectors

    International Nuclear Information System (INIS)

    Frank, E.

    1975-01-01

    An elevator mechanism and method for raising and lowering radioactive samples through a shielded vertical counting chamber in a benchtop scintillation detector is described. The elevator mechanism adds little or nothing to the height of the detector by using an elongated flexible member such as a metal tape secured to the bottom of the elevator platform and extending downwardly through the counting chamber and its bottom shielding, where the tape is bent laterally for connection to a drive means. In the particular embodiment illustrated, the tape is bent laterally below the bottom shielding for the counting chamber, and then upwardly along or through one side of the shielding to a reel at the top of the shielding. The tape is wound onto the reel, and the reel is driven by a reversible motor which winds and unwinds the tape on the reel to raise and lower the elevator platform

  15. Homestake surface-underground scintillators: Initial results

    International Nuclear Information System (INIS)

    Cherry, M.L.; Corbato, S.; Daily, T.; Fenyves, E.J.; Kieda, D.; Lande, K.; Lee, C.K.

    1986-01-01

    The first 70 tons of the 140-ton Large Area Scintillation Detector (LASD) have been operating since Jan. 1985 at a depth of 4850 ft. (4200 m.w.e.) in the Homestake Gold Mine, Lead, S.D. A total of 4 x 10(4) high-energy muons (E sub mu is approx. 2.7 TeV at the surface) have been detected. The remainder of the detector is scheduled to be in operation by the Fall of 1985. In addition, a surface air shower array is under construction. The first 27 surface counters, spaced out over an area of 270' x 500', began running in June, 1985. The LASD performance, the potential of the combined shower array and underground muon experiment for detecting point sources, and the initial results of a search for periodic emission from Cygnus X-3 are discussed

  16. Borehole instrument for scintillation gamma spectrometer

    International Nuclear Information System (INIS)

    Sinitsyn, A.Ya.; Gabitov, R.M.

    1979-01-01

    Described are a schematic diagram and main specifications of a borehole instrument with autostabilization of energy scale measure by gamma bench-mark of 137 Cs, intended for the application in a logging gamma spectrometer to determine separately the concentrations of nature radioactive elements. The instrument may be connected to the KOBDFM-2 cable of 600 m length. It contains a scintillation counter for gamma quanta consisting of 30x70 mm NaI(Tl) crystal and a FEU-85 photoamplifier, an input conforming stage, a diagram of threshold pulse formation and regulating high-voltage generator. The borehole instrument has been proved under laboratory and field conditions at 10-40 deg C

  17. Liquid xenon/krypton scintillation calorimeter

    International Nuclear Information System (INIS)

    Akimov, D.Yu.; Bolozdynya, A.I.; Brastilov, A.D.

    1994-01-01

    A scintillating LXe/LKr electromagnetic calorimeter has been built at the ITEP and tested at the BATES (MIT) accelerator. The detector consists of PMT matrix and 45 light collecting cells made of aluminized 50 microns Mylar partially covered with p-terphenyl as a wavelength-shifter. Each pyramidal cell has (2.1 x 2.1) x 40 x (4.15 x 4.15) cm dimensions and is viewed by FEU-85 glass-window photomultiplier. The detector has been exposed at 106-348 MeV electron beam. The energy resolution σ E /E ≅ 5% √ E at 100 - 350 MeV range in LXe, the coordinate resolution τ x ≅ 0.7 cm, the time resolution for single cell ≅ 0.6 ns have been obtained. Possible ways to improve energy resolution are discussed. 8 refs., 15 figs

  18. Radiation dosimeter built with plastic scintillator

    International Nuclear Information System (INIS)

    Barrea, R.A.

    1990-01-01

    Ionization chambers, with air equivalent plastic walls, have been used as the main x-ray dosimetry system, since its response permits to give the doses in Roentgens. From the commercial availability of plastic scintillators with air equivalent atomic number we have studied its use in x-ray dosimetry. This paper devised a system with which it is possible to reduce side effects that introduce errors and obtain a response independent of energy, from 20 to 180 KeV and it is also expected to behave that way for higher energies. The system has a high efficiency and precision for a wide dose range and it is then a new alternative to measure x-ray doses. Results obtained with a prototype, built ad-hog, make it possible its use with dosimetric purposes with several advantages over conventional. (author)

  19. Advances in semiconductor photodetectors for scintillators

    International Nuclear Information System (INIS)

    Farrell, R.; Olschner, F.; Shah, K.; Squillante, M.R.

    1997-01-01

    Semiconductors photodetectors have long seemed an attractive alternative for scintillation detection, but only recently have semiconductor photodiodes been proven suitable for some room temperature applications. There are many applications, however for which the performance of standard silicon p-i-n photodiodes is not satisfactory. This article reviews recent progress in two different families of novel semiconductor photodetectors: (1) wide bandgap compound semiconductors and (2) silicon photodetectors with enhanced signal-to-noise ratio. The compounds discussed and compared in this paper are HgI 2 , PbI 2 , InI, TlBr, TlBr 1-x I x and HgBr 1-x I x . The paper will also examine unity gain silicon drift diodes and avalanche photodiodes with maximum room temperature gain greater than 10000. (orig.)

  20. Liquid scintillation counting analysis of cadmium-109

    International Nuclear Information System (INIS)

    Robinson, M.K.; Barfuss, D.W.

    1991-01-01

    Recently the authors have used radiolabled cadmium-109 to measure the transport of inorganic cadmium in renal proximal tubules. An anomaly discovered in the liquid scintillation counting analysis of Cd-109 which is not attributable to normal decay; it consists of a significant decrease in the measured count rate of small amounts of sample. The objective is to determine whether the buffer solution used in the membrane transport studies is causing precipitation of the cadmium or whether cadmium is being adsorbed by the glass. It was important to determine whether the procedure could be modified to correct this problem. The problem does not appear to be related to the use of the buffer or to adsorption of Cd onto glass. Correction based on using triated L-glucose in all of these experiments and calculating a correction factor for the concentration of cadmium

  1. Upgradation of automatic liquid scintillation counting system

    International Nuclear Information System (INIS)

    Bhattacharya, Sadhana; Behere, Anita; Sonalkar, S.Y.; Vaidya, P.P.

    2001-01-01

    This paper describes the upgradation of Microprocessor based Automatic Liquid Scintillation Counting systems (MLSC). This system was developed in 1980's and subsequently many systems were manufactured and supplied to Environment Survey labs at various Nuclear Power Plants. Recently this system has been upgraded to a more sophisticated one by using PC add-on hardware and developing Windows based software. The software implements more intuitive graphical user interface and also enhances the features making it comparable with commercially available systems. It implements data processing using full spectrum analysis as against channel ratio method adopted earlier, improving the accuracy of the results. Also it facilitates qualitative as well as quantitative analysis of the β-spectrum. It is possible to analyze a sample containing an unknown β-source. (author)

  2. Scintillation light detectors with Neganov Luke amplification

    Science.gov (United States)

    Isaila, C.; Boslau, O.; Coppi, C.; Feilitzsch, F. v.; Goldstraß, P.; Jagemann, T.; Jochum, J.; Kemmer, J.; Lachenmaier, T.; Lanfranchi, J.-C.; Pahlke, A.; Potzel, W.; Rau, W.; Stark, M.; Wernicke, D.; Westphal, W.

    2006-04-01

    For an active suppression of the gamma and electron background in the Cryogenic Rare Event Search with Superconducting Thermometers (CRESST) dark matter experiment both phonons and scintillation light generated in a CaWO 4 crystal are detected simultaneously. The phonon signal is read out by a transition edge sensor (TES) on the CaWO 4 crystal. For light detection a silicon absorber equipped with a TES is employed. An efficient background discrimination requires very sensitive light detectors. The threshold can be improved by applying an electric field to the silicon crystal leading to an amplification of the thermal signal due to the Neganov-Luke effect. Measurements showing the improved sensitivity of the light detectors as well as future steps for reducing the observed extra noise will be presented.

  3. The theory of scintillation with applications in remote sensing

    CERN Document Server

    Rino, Charles

    2011-01-01

    "In order to truly understand data signals transmitted by satellite, one must understand scintillation theory in addition to well established theories of EM wave propagation and scattering. Scintillation is a nuisance in satellite EM communications, but it has stimulated numerous theoretical developments with science applications. This book not only presents a thorough theoretical explanation of scintillation, but it also offers a complete library of MATLAB codes that will reproduce the book examples. The library includes GPS coordinate manipulations, satellite orbit prediction, and earth mean magnetic field computations. The subect matter is for EM researchers; however, also theory is relevant to geophysics, acoustics, optics and astoronomy"--Provided by publisher.

  4. Quenching the scintillation in CF4 Cherenkov gas radiator

    International Nuclear Information System (INIS)

    Blake, T.; D'Ambrosio, C.; Easo, S.; Eisenhardt, S.; Fitzpatrick, C.; Forty, R.; Frei, C.; Gibson, V.; Gys, T.; Harnew, N.; Hunt, P.; Jones, C.R.; Lambert, R.W.; Matteuzzi, C.; Muheim, F.; Papanestis, A.; Perego, D.L.; Piedigrossi, D.; Plackett, R.; Powell, A.

    2015-01-01

    CF 4 is used as a Cherenkov gas radiator in one of the Ring Imaging Cherenkov detectors at the LHCb experiment at the CERN Large Hadron Collider. CF 4 is well known to have a high scintillation photon yield in the near and far VUV, UV and in the visible wavelength range. A large flux of scintillation photons in our photon detection acceptance between 200 and 800 nm could compromise the particle identification efficiency. We will show that this scintillation photon emission system can be effectively quenched, consistent with radiationless transitions, with no significant impact on the photons resulting from Cherenkov radiation

  5. Trigger and electronics issues for scintillating fiber tracking

    International Nuclear Information System (INIS)

    Baumbaugh, A.E.

    1994-01-01

    Scintillating Fiber technology has made great advances and has demonstrated great promise for high speed charged particle tracking and triggering. The small detector sizes and fast scintillation floors available, make them very promising for use at high luminosity experiments at today's and tomorrow's colliding and fixed target experiments where high rate capability is essential. This paper will discuss some of the system aspects which should be considered by anyone attempting to design a scintillating fiber tracking system and high speed tracking trigger. As the reader will see, seemingly simple decisions can have far reaching effects on overall system performance

  6. 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.

  7. Scintillation trigger system of the liquid argon neutrino detector

    International Nuclear Information System (INIS)

    Belikov, S.V.; Gurzhiev, S.N.; Gutnikov, Yu.E.; Denisov, A.G.; Kochetkov, V.I.; Matveev, M.Yu.; Mel'nikov, E.A.; Usachev, A.P.

    1994-01-01

    This paper presents the organization of the Scintillation Trigger System (STS) for the Liquid Argon Neutrino Detector of the Tagged Neutrino Facility. STS is aimed at the effective registration of the needed neutrino interaction type and production of a fast trigger signal with high time resolution. The fast analysis system of analog signal from the trigger scintillation planes for rejection of the trigger signals from background processes is described. Real scintillation trigger planes characteristics obtained on the basis of the presented data acquisition system are shown. 10 refs., 12 figs., 3 tabs

  8. Amplitude scintillations of ATS-6 radio signals in Lannion

    International Nuclear Information System (INIS)

    Cornec, J.P.

    1978-01-01

    The paper reports the results of a study of the scintillations observed on the amplitude of signal transmitted by the geostationary satellite ATS-6 on 40, 140, and 360 MHz, received at Lannion, France. Diffraction patterns caused bubbles of irregularities are studied and found to be mainly a summer phenomenon. It is concluded that there is a great increase in frequency occurrence and in the strength of scintillations from winter to summer, and that for the whole observation period, scintillation is mainly a nighttime pheonomenon, reaching its maximum activity at 2100-2200

  9. Design and Prototyping of a High Granularity Scintillator Calorimeter

    International Nuclear Information System (INIS)

    Zutshi, Vishnu

    2016-01-01

    A novel approach for constructing fine-granularity scintillator calorimeters, based on the concept of an Integrated Readout Layer (IRL) was developed. The IRL consists of a printed circuit board inside the detector which supports the directly-coupled scintillator tiles, connects to the surface-mount SiPMs and carries the necessary front-end electronics and signal/bias traces. Prototype IRLs using this concept were designed, prototyped and successfully exposed to test beams. Concepts and implementations of an IRL carried out with funds associated with this contract promise to result in the next generation of scintillator calorimeters.

  10. Ionization and scintillation of nuclear recoils in gaseous xenon

    Energy Technology Data Exchange (ETDEWEB)

    Renner, J., E-mail: jrenner@lbl.gov [Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Road, Berkeley, CA 94720 (United States); Department of Physics, University of California, Berkeley, CA 94720 (United States); Gehman, V.M.; Goldschmidt, A.; Matis, H.S.; Miller, T.; Nakajima, Y.; Nygren, D.; Oliveira, C.A.B.; Shuman, D. [Lawrence Berkeley National Laboratory (LBNL), 1 Cyclotron Road, Berkeley, CA 94720 (United States); Álvarez, V. [Instituto de Física Corpuscular (IFIC), CSIC & Universitat de València, Calle Catedrático José Beltrán, 2, 46980 Paterna, Valencia (Spain); Borges, F.I.G. [Departamento de Fisica, Universidade de Coimbra, Rua Larga, 3004-516 Coimbra (Portugal); Cárcel, S. [Instituto de Física Corpuscular (IFIC), CSIC & Universitat de València, Calle Catedrático José Beltrán, 2, 46980 Paterna, Valencia (Spain); Castel, J.; Cebrián, S. [Laboratorio de Física Nuclear y Astropartículas, Universidad de Zaragoza, Calle Pedro Cerbuna 12, 50009 Zaragoza (Spain); Cervera, A. [Instituto de Física Corpuscular (IFIC), CSIC & Universitat de València, Calle Catedrático José Beltrán, 2, 46980 Paterna, Valencia (Spain); Conde, C.A.N. [Departamento de Fisica, Universidade de Coimbra, Rua Larga, 3004-516 Coimbra (Portugal); and others

    2015-09-01

    Ionization and scintillation produced by nuclear recoils in gaseous xenon at approximately 14 bar have been simultaneously observed in an electroluminescent time projection chamber. Neutrons from radioisotope α-Be neutron sources were used to induce xenon nuclear recoils, and the observed recoil spectra were compared to a detailed Monte Carlo employing estimated ionization and scintillation yields for nuclear recoils. The ability to discriminate between electronic and nuclear recoils using the ratio of ionization to primary scintillation is demonstrated. These results encourage further investigation on the use of xenon in the gas phase as a detector medium in dark matter direct detection experiments.

  11. Scintillating fibre detectors using position-sensitive photomultipliers

    International Nuclear Information System (INIS)

    Agoritsas, V.; Bergdolt, A.M.; Bing, O.; Bravar, A.; Ditta, J.; Drevenak, R.

    1995-01-01

    Scintillating fibre technology has made substantial progress, and has demonstrated great potential for fast tracking and triggering in high luminosity experiments in Particle Physics. Some recent issues of the RD-17 project at CERN are presented for fast and precise readout of scintillating fibre arrays, as well as for upgrade of position-sensitive photomultipliers. Excellent matching of the scintillating fibre and the position-sensitive photomultiplier, in particular in time characteristics, allowed to achieve excellent detector performances, typically a spatial resolution of ∼ 125 μm with time resolution better than 1 ns and detection efficiency greater than 95%. (author)10 refs.; 25 figs.; 1 tab

  12. Pulse discrimination of scintillator detector with artificial neural network

    International Nuclear Information System (INIS)

    Chen Man; Cai Yuerong; Yang Chaowen

    2006-01-01

    The features of signal for scintillator detectors are analyzed. According to the difference in the fraction of slow and fast scintillation for different particles, three intrinsic parameters (signal amplitude, integration of signal during rinsing, integration of frequency spectrum of signals in middle frequencies) of signals are defined. The artificial neural network method for pulse discrimination of scintillator detector is studied. The signals with different shapes under real condition are simulated with computer, and discriminated by the method. Results of discrimination are gotten and discussed. (authors)

  13. An integrated photosensor readout for gas proportional scintillation counters

    International Nuclear Information System (INIS)

    Lopes, J.A.M.; Santos, J.M.F. dos; Conde, C.A.N.

    1996-01-01

    A xenon gas proportional scintillation counter has been instrumented with a novel photosensor that replaces the photomultiplier tube normally used to detect the VUV secondary scintillation light. In this implementation, the collection grid of a planar gas proportional scintillation counter also functions as a multiwire proportional chamber to amplify and detect the photoelectrons emitted by a reflective CsI photocathode in direct contact with the xenon gas. This integrated concept combines greater simplicity, compactness, and ruggedness (no optical window is used) with low power consumption. An energy resolution of 12% was obtained for 59.6 keV x-rays

  14. Liquid scintillation spectrometer survey 155Eu liquid activity

    International Nuclear Information System (INIS)

    Zhang Zuhua

    2002-01-01

    In the countrywide contrasting survey of 155 Eu activity, 155 Eu liquid activity was determined for the first time through using liquid scintillation spectrometer survey 155 Eu β ray. In survey total uncertainty, determining activity accord with determining activity average value of all a wide variety of survey instrument entering into contrasting survey. But using liquid scintillation spectrometer survey, it is simple and save time, is beyond compare for other survey method. It indicate liquid scintillation spectrometer survey β-γ nuclide activity is effective as well

  15. Design and Prototyping of a High Granularity Scintillator Calorimeter

    Energy Technology Data Exchange (ETDEWEB)

    Zutshi, Vishnu [Northern Illinois Univ., DeKalb, IL (United States). Dept. of Physics

    2016-03-27

    A novel approach for constructing fine-granularity scintillator calorimeters, based on the concept of an Integrated Readout Layer (IRL) was developed. The IRL consists of a printed circuit board inside the detector which supports the directly-coupled scintillator tiles, connects to the surface-mount SiPMs and carries the necessary front-end electronics and signal/bias traces. Prototype IRLs using this concept were designed, prototyped and successfully exposed to test beams. Concepts and implementations of an IRL carried out with funds associated with this contract promise to result in the next generation of scintillator calorimeters.

  16. GAGG:ce single crystalline films: New perspective scintillators for electron detection in SEM

    International Nuclear Information System (INIS)

    Bok, Jan; Lalinský, Ondřej; Hanuš, Martin; Onderišinová, Zuzana; Kelar, Jakub; Kučera, Miroslav

    2016-01-01

    Single crystal scintillators are frequently used for electron detection in scanning electron microscopy (SEM). We report gadolinium aluminum gallium garnet (GAGG:Ce) single crystalline films as a new perspective scintillators for the SEM. For the first time, the epitaxial garnet films were used in a practical application: the GAGG:Ce scintillator was incorporated into a SEM scintillation electron detector and it showed improved image quality. In order to prove the GAGG:Ce quality accurately, the scintillation properties were examined using electron beam excitation and compared with frequently used scintillators in the SEM. The results demonstrate excellent emission efficiency of the GAGG:Ce single crystalline films together with their very fast scintillation decay useful for demanding SEM applications. - Highlights: • First practical application of epitaxial garnet films demonstrated in SEM. • Improved image quality of SEM equipped with GAGG:Ce single crystalline thin film scintillator. • Scintillation properties of GAGG:Ce films compared with standard bulk crystal scintillators.

  17. Co-doping effects on luminescence and scintillation properties of Ce doped Lu3Al5O12 scintillator

    International Nuclear Information System (INIS)

    Kamada, Kei; Nikl, Martin; Kurosawa, Shunsuke; Beitlerova, Alena; Nagura, Aya; Shoji, Yasuhiro; Pejchal, Jan; Ohashi, Yuji; Yokota, Yuui; Yoshikawa, Akira

    2015-01-01

    The Mg, Ca, Sr and Ba 200 ppm co-doped Ce:Lu 3 Al 5 O 12 single crystals were prepared by micro pulling down method. Absorption and luminescence spectra were measured together with several other scintillation characteristics, namely the scintillation decay and light yield to reveal the effect of the co-doping. The scintillation decays were accelerated by both Mg and Ca co-dopants. The Mg co-doped samples showed the fastest decay and the highest light yield among the co-doped samples

  18. Production of the Large-area Plastic Scintillator for Beta-ray Detection using Epoxy Resin

    International Nuclear Information System (INIS)

    Nam, Jong Soo; Choi, Yong Seok; Hong, Sang Bum; Seo, Bum Kyung; Moon, Jei Kwon; Choi, Jong Won

    2016-01-01

    In this study, we prepared a plastic scintillator whose manufacturing process is simple and can be freely shaped. A thin plate of the plastic scintillator was manufactured using epoxy resin as a polymer. The plastic scintillator was made by mixing epoxy resin and organic scintillators under various conditions. The optimal mixture ratio to prepare the plastic scintillator was derived from the above results. Using the derived results, we made the large-area plastic scintillator which can quickly measure the contamination site and evaluated characteristics of the large-area plastic scintillator in the laboratory. A thin plate of a plastic scintillator with a simple preparation process can be freely shaped using epoxy resin and organic scintillators such as PPO and POPOP. PPO emits scintillation of light in the ultraviolet range, and POPOP is a wave shifter for moving the wavelength responsible for the PMT. The mixture ratio of PPO and POPOP was determined using their emission spectra. The optimal weight percentage of PPO and POPOP in an organic scintillator was determined to be 0.2 wt%:0.01 wt%. Based on the above results, the large-area plastic scintillator of the window size of a typical pancake-type αβ surface contamination counter was prepared. We want to evaluate the characteristics of the large-area plastic scintillator. However, there were the difficulties in evaluating characteristics of the large-area plastic scintillator. The cross-sectional area of the large-area plastic scintillator is significantly different to PMT

  19. Production of the Large-area Plastic Scintillator for Beta-ray Detection using Epoxy Resin

    Energy Technology Data Exchange (ETDEWEB)

    Nam, Jong Soo; Choi, Yong Seok; Hong, Sang Bum; Seo, Bum Kyung; Moon, Jei Kwon; Choi, Jong Won [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    In this study, we prepared a plastic scintillator whose manufacturing process is simple and can be freely shaped. A thin plate of the plastic scintillator was manufactured using epoxy resin as a polymer. The plastic scintillator was made by mixing epoxy resin and organic scintillators under various conditions. The optimal mixture ratio to prepare the plastic scintillator was derived from the above results. Using the derived results, we made the large-area plastic scintillator which can quickly measure the contamination site and evaluated characteristics of the large-area plastic scintillator in the laboratory. A thin plate of a plastic scintillator with a simple preparation process can be freely shaped using epoxy resin and organic scintillators such as PPO and POPOP. PPO emits scintillation of light in the ultraviolet range, and POPOP is a wave shifter for moving the wavelength responsible for the PMT. The mixture ratio of PPO and POPOP was determined using their emission spectra. The optimal weight percentage of PPO and POPOP in an organic scintillator was determined to be 0.2 wt%:0.01 wt%. Based on the above results, the large-area plastic scintillator of the window size of a typical pancake-type αβ surface contamination counter was prepared. We want to evaluate the characteristics of the large-area plastic scintillator. However, there were the difficulties in evaluating characteristics of the large-area plastic scintillator. The cross-sectional area of the large-area plastic scintillator is significantly different to PMT.

  20. Final LDRD report : advanced plastic scintillators for neutron detection.

    Energy Technology Data Exchange (ETDEWEB)

    Vance, Andrew L.; Mascarenhas, Nicholas; O' Bryan, Greg; Mrowka, Stanley

    2010-09-01

    This report summarizes the results of a one-year, feasibility-scale LDRD project that was conducted with the goal of developing new plastic scintillators capable of pulse shape discrimination (PSD) for neutron detection. Copolymers composed of matrix materials such as poly(methyl methacrylate) (PMMA) and blocks containing trans-stilbene (tSB) as the scintillator component were prepared and tested for gamma/neutron response. Block copolymer synthesis utilizing tSBMA proved unsuccessful so random copolymers containing up to 30% tSB were prepared. These copolymers were found to function as scintillators upon exposure to gamma radiation; however, they did not exhibit PSD when exposed to a neutron source. This project, while falling short of its ultimate goal, demonstrated the possible utility of single-component, undoped plastics as scintillators for applications that do not require PSD.

  1. Scintillation chamber of calorimeters for colliding beam detectors

    International Nuclear Information System (INIS)

    Jones, L.W.

    1983-01-01

    It is suggested that the scintillation chamber, a technique first discussed almost thirty years ago, might find application in colliding beam detector systems, in particular as a means of efficiently extracting detailed spatial and energy information from a sampling calorimeter

  2. A sensitivity analysis approach to optical parameters of scintillation detectors

    International Nuclear Information System (INIS)

    Ghal-Eh, N.; Koohi-Fayegh, R.

    2008-01-01

    In this study, an extended version of the Monte Carlo light transport code, PHOTRACK, has been used for a sensitivity analysis to estimate the importance of different wavelength-dependent parameters in the modelling of light collection process in scintillators

  3. A lens-coupled scintillation counter in cryogenic environment

    International Nuclear Information System (INIS)

    Stoykov, A; Scheuermann, R; Amato, A; Bartkowiak, M; Konter, J A; Rodriguez, J; Sedlak, K

    2011-01-01

    In this work we present an elegant solution for a scintillation counter to be integrated into a cryogenic system. Its distinguishing feature is the absence of a continuous light guide coupling the scintillation and the photodetector parts, operating at cryogenic and room temperatures respectively. The prototype detector consists of a plastic scintillator with glued-in wavelength-shifting fiber located inside a cryostat, a Geiger-mode Avalanche Photodiode (G-APD) outside the cryostat, and a lens system guiding the scintillation light re-emitted by the fiber to the G-APD through optical windows in the cryostat shields. With a 0.8 mm diameter multiclad fiber and a 1 mm active area G-APD the coupling efficiency of the 'lens light guide' is about 50%. A reliable performance of the detector down to 3 K is demonstrated.

  4. Use of pliable bags in liquid scintillation counting

    International Nuclear Information System (INIS)

    Simonnet, G.; Jacquet, M.A.; Sharif, A.; Engler, R.

    1981-01-01

    Pliable plastic bags have been used to replace glass or plastic vials for liquid scintillation counting. The two major advantages of this method are the lower cost of the plastic bags and the fact that, per sample, the radioactive waste is significantly reduced. The following parameters have been checked: the impermeability of the bags to various scintillator mixtures and the fact that neither the irregular shape of the bags nor their position in the counting chamber had any effect on the results of the counting. The latter was also constant with time, at least over a period of 10 days. The technique has been used to count the radioactivity of 3 H-DNA precipitates prepared from bacteria and lymphocytes and deposited on filters impregnated with only 200 μl scintillator. It is a method that can be applied to the counting of any samples deposited on filters and insoluble in scintillator. (author)

  5. Production and thickness determination of thin plastic scintillator foils

    International Nuclear Information System (INIS)

    Xiao, B.; Lee, S.; Hagel, K.; Haddad, F.; Li, J.; Lou, Y.; Mdeiwayeh, N.; Tezkratt, R.; Wada, R.; Utley, D.; Natowitz, J.B.

    1995-01-01

    A method of making large thin plastic scintillator foils with good uniformity is presented. The use of Fourier Transform Infrared Spectroscopy (FTIR) to test the foil uniformity and to establish an empirical thickness calibration curve is described. ((orig.))

  6. Scintillation Particle Detectors Based on Plastic Optical Fibres and Microfluidics

    CERN Document Server

    Mapelli, Alessandro; Renaud, Philippe

    2011-01-01

    This thesis presents the design, development, and experimental validation of two types of scintillation particle detectors with high spatial resolution. The first one is based on the well established scintillating fibre technology. It will complement the ATLAS (A Toroidal Large ApparatuS) detector at the CERN Large Hadron Collider (LHC). The second detector consists in a microfabricated device used to demonstrate the principle of operation of a novel type of scintillation detector based on microfluidics. The first part of the thesis presents the work performed on a scintillating fibre tracking system for the ATLAS experiment. It will measure the trajectory of protons elastically scattered at very small angles to determine the absolute luminosity of the CERN LHC collider at the ATLAS interaction point. The luminosity of an accelerator characterizes its performance. It is a process-independent parameter that is completely determined by the properties of the colliding beams and it relates the cross section of a ...

  7. Gamma spectrometry and plastic-scintillator inherent background

    International Nuclear Information System (INIS)

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

    1988-01-01

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

  8. Search of new scintillation materials for nuclear medicine application

    CERN Document Server

    Korzhik, M

    2001-01-01

    Oxide crystals have a great potential to develop new advanced scintillation materials which are dense, fast, and bright. This combination of parameters, when combined to affordable price, gives a prospect for materials to be applied in nuclear medicine devices. Some of them have been developed for the last two decades along the line of rear-earth (RE) garnet (RE//3Al//5O//1//2) oxiorthosilicate (RE//2SiO//5) and perovskite (REAlO//3) crystals doped with Ce ions. Among recently developed oxide materials the lead tungstate scintillator (PWO) becomes the most used scintillation materials in high energy physics experiments due to its application in CMS and ALICE experiments at LHC. In this paper we discuss scintillation properties of some new heavy compounds doped with Ce as well as light yield improvement of PWO crystals to apply them in low energy physics and nuclear medicine. 18 Refs.

  9. Radiation effects in polymers for plastic scintillation detectors

    International Nuclear Information System (INIS)

    Pla-Dalmau, A.; Bross, A.D.; Hurlbut, C.R.; Moser, S.W.

    1994-01-01

    Recent developments in both scintillating plastic optical fibers and photon detection devices have spawned new applications for plastic scintillator detectors. This renewed attention has encouraged research that addresses the radiation stability of plastic scintillators. The optical quality of the polymer degrades with exposure to ionizing radiation and thus the light yield of the detector decreases. A complete understanding of all the mechanisms contributing to this radiation-induced degradation of the polymer can lead to techniques that will extend the radiation stability of these materials. Various radiation damage studies have been performed under different atmospheres and dose rates. Currently, the use of additives to preserve the optical properties of the polymer matrix under radiation is being investigated. The authors discuss the effect of certain antioxidants, plasticizers, and cross-linking agents on the radiation resilience of plastic scintillators

  10. Discrimination of Naturally Occurring Radioactive Material in Plastic Scintillator Material

    International Nuclear Information System (INIS)

    Ely, James H.; Kouzes, Richard T.; Geelhood, Bruce D.; Schweppe, John E.; Warner, Ray A.

    2003-01-01

    Plastic scintillator material is used in many applications for the detection of gamma-rays from radioactive material, primarily due to the sensitivity per unit cost compared to other detection materials. However, the resolution and lack of full-energy peaks in the plastic scintillator material prohibits detailed spectroscopy. Therefore, other materials such as doped sodium iodide are used for spectroscopic applications. The limited spectroscopic information can however be exploited in plastic scintillator materials to provide some discrimination. The discrimination between man-made and naturally occurring sources would be useful in reducing alarm screening for radiation detection applications which target man-made sources. The results of applying the limited energy information from plastic scintillator material for radiation portal monitors are discussed.

  11. LET dependence of scintillation yields in liquid argon

    Energy Technology Data Exchange (ETDEWEB)

    Doke, Tadayoshi; Hitachi, Akira; Kikuchi, Jun; Crawford, H J; Lindstrom, P J; Masuda, Kimiaki; Shibamura, Eido; Takahashi, Tan

    1988-06-01

    Scintillation yields (scintillation intensity per unit absorbed energy) in liquid argon for ionizing particles are reviewed as a function of LET for the particles. The maximum scintillation yield, which is obtained for relativistic heavy ions from Ne to La, is about 1.2 times larger than that for gamma rays in NaI(Tl) crystal. In the low LET region, the scintillation yields for relativistic electrons, protons and He ions are 10-20% lower than the maximum yield. This tendency can be explained by taking into account the existence of the electrons which have escaped from their parent ions. In the high LET region, a quenching effect due to high ionization density is observed for alpha particles, fission fragments and relativistic Au ions.

  12. Inorganic scintillators for detector systems physical principles and crystal engineering

    CERN Document Server

    Lecoq, Paul; Korzhik, Mikhail

    2017-01-01

    This second edition features new chapters highlighting advances in our understanding of the behavior and properties of scintillators, and the discovery of new families of materials with light yield and excellent energy resolution very close to the theoretical limit. The book focuses on the discovery of next-generation scintillation materials and on a deeper understanding of fundamental processes. Such novel materials with high light yield as well as significant advances in crystal engineering offer exciting new perspectives. Most promising is the application of scintillators for precise time tagging of events, at the level of 100 ps or higher, heralding a new era in medical applications and particle physics. Since the discovery of the Higgs Boson with a clear signature in the lead tungstate scintillating blocks of the CMS Electromagnetic Calorimeter detector, the current trend in particle physics is toward very high luminosity colliders, in which timing performance will ultimately be essential to mitigating...

  13. A more rugged ZnS(Ag) alpha scintillation detector

    International Nuclear Information System (INIS)

    McElhaney, S.A.; Ramsey, J.A.; Bauer, M.L.; Chiles, M.M.

    1990-01-01

    Conventional alpha scintillation detectors comprise a phosphor-coated light-pipe covered by a thin aluminized Mylar layer. This opaque radiation entrance window serves as a shield against ambient light entering the detector with minimum alpha attenuation. Unfortunately, Mylar is extremely fragile and easily punctured or torn by sticks, stones, and screws encountered during regular radiation surveys. The authors have been developing an alpha scintillation detector more rugged and durable than conventional models. This paper presents the scintillator assembly, which consists of a mixture of silver-activated zinc sulfide [ZnS(Ag)] and clear epoxy. The ZnS(Ag) scintillation powder is mixed with a low-viscosity, optically transparent epoxy and poured into a glass-smooth mold of desired shape and size

  14. Photonic Crystals: Enhancing the Light Output of Scintillation Based Detectors

    CERN Document Server

    Knapitsch, Arno Richard

    A scintillator is a material which emits light when excited by ionizing radiation. Such materials are used in a diverse range of applications; From high energy particle physics experiments, X-ray security, to nuclear cameras or positron emission tomography. Future high-energy physics (HEP) experiments as well as next generation medical imaging applications are more and more pushing towards better scintillation characteristics. One of the problems in heavy scintillating materials is related to their high index of refraction. As a consequence, most of the scintillation light produced in the bulk material is trapped inside the crystal due to total internal reflection. The same problem also occurs with light emitting diodes (LEDs) and has for a long time been considered as a limiting factor for their overall efficiency. Recent developments in the area of nanophotonics were showing now that those limitations can be overcome by introducing a photonic crystal (PhC) slab at the outcoupling surface of the substrate. P...

  15. Large liquid-scintillator trackers for neutrino experiments

    CERN Document Server

    Benussi, L; D'Ambrosio, N; Déclais, Y; Dupraz, J P; Fabre, Jean-Paul; Fanti, V; Forton, E; Frekers, D; Frenkel, A; Girerd, C; Golovkin, S V; Grégoire, G; Harrison, K; Jonkmans, G; Jonsson, P; Katsanevas, S; Kreslo, I; Marteau, J; Martellotti, G; Martínez, S; Medvedkov, A M; Moret, G; Niwa, K; Novikov, V; Van Beek, G; Penso, G; Vasilchenko, V G; Vuilleumier, J L; Wilquet, G; Zucchelli, P; Kreslo, I E

    2002-01-01

    Results are given on tests of large particle trackers for the detection of neutrino interactions in long-baseline experiments. Module prototypes have been assembled using TiO$_2$-doped polycarbonate panels. These were subdivided into cells of $\\sim 1$~cm$^2$ cross section and 6~m length, filled with liquid scintillator. A wavelength-shifting fibre inserted in each cell captured a part of the scintillation light emitted when a cell was traversed by an ionizing particle. Two different fibre-readout systems have been tested: an optoelectronic chain comprising an image intensifier and an Electron Bombarded CCD (EBCCD); and a hybrid photodiode~(HPD). New, low-cost liquid scintillators have been investigated for applications in large underground detectors. Testbeam studies have been performed using a commercially available liquid scintillator. The number of detected photoelectrons for minimum-ionizing particles crossing a module at different distances from the fibre readout end was 6 to 12 with the EBCCD chain and ...

  16. Recent developments in plastic scintillators with pulse shape discrimination

    Science.gov (United States)

    Zaitseva, N. P.; Glenn, A. M.; Mabe, A. N.; Carman, M. L.; Hurlbut, C. R.; Inman, J. W.; Payne, S. A.

    2018-05-01

    The paper reports results of studies conducted to improve scintillation performance of plastic scintillators capable of neutron/gamma pulse-shape discrimination (PSD). Compositional modifications made with the polymer matrix improved physical stability, allowing for increased loads of the primary dye that, in combination with selected secondary dyes, provided enhanced PSD especially important for the lower energy ranges. Additional measurements were made with a newly-introduced PSD plastic EJ-276, that replaces the first commercially produced EJ-299. Comparative studies conducted with the new materials and EJ-309 liquids at large scale (up to 10 cm) show that current plastics may provide scintillation and PSD performance sufficient for the replacement of liquid scintillators. Comparison to stilbene single crystals compliments the information about the status of the solid-state materials recently developed for fast neutron detection applications.

  17. Comparison of the methods for determination of scintillation light yield

    CERN Document Server

    Sysoeva, E; Zelenskaya, O

    2002-01-01

    One of the most important characteristics of scintillators is the light yield. It depends not only on the properties of scintillators, but also on the conditions of measurements. Even for widely used crystals, such as alkali halide scintillators NaI(Tl) and CsI(Tl), light yield data, obtained by various authors, are different. Therefore, it is very important to choose the convenient method of the light yield measurements. In the present work, methods for the determination of the physical light yield, based on measurements of pulse amplitude, single-electron pulses and intrinsic photomultiplier resolution are discussed. These methods have been used for the measurements of light yield of alkali halide crystals and oxide scintillators. Repeatability and reproducibility of results were determined. All these methods are rather complicated in use, not for measurements, but for further data processing. Besides that, they demand a precise determination of photoreceiver's parameters, as well as determination of light ...

  18. Liquid scintillation cocktails comparison for tritium contamination measurements

    International Nuclear Information System (INIS)

    Bazzarri, S.; Belloni, P.

    1996-01-01

    Liquid scintillation counting is one of the most used techniques for the measurements of tritium contamination. Until few years ago a problem related to this kind of measurement was the potential toxicity of the liquid cocktails used to produce the required scintillation. Some new products that guarantee an almost negligible impact on the environment and that are no longer toxic for the operators are now available. Some of this new scintillation cocktail are suitable to be used for tritium measurement. Due to the great benefit from the health point of view of these new materials a test of their scintillation performance has been done at the ENEA centers to select the product having the best characteristics for tritium measurement. (author)

  19. Set of counts by scintillations for atmospheric samplings

    International Nuclear Information System (INIS)

    Appriou, D.; Doury, A.

    1962-01-01

    The author reports the development of a scintillation-based counting assembly with the following characteristics: a photo-multiplier with a wide photo-cathode, a thin plastic scintillator for the counting of beta + alpha (and possibility of mounting an alpha scintillator), a relatively small own motion with respect to activities to be counted, a weakly varying efficiency. The authors discuss the counting objective, present equipment tests (counter, proportional amplifier and pre-amplifier, input drawer). They describe the apparatus operation, discuss the selection of scintillators, report the study of the own movement (electron-based background noise, total background noise, background noise reduction), discuss counts (influence of the external source, sensitivity to alpha radiations, counting homogeneity, minimum detectable activity) and efficiencies

  20. Improved terbium-doped, lithium-loaded glass scintillator fibers

    International Nuclear Information System (INIS)

    Spector, G.B.; McCollum, T.; Spowart, A.R.

    1993-01-01

    An improved terbium-doped, 6 Li-loaded glass scintillator has been drawn into fibers. Tests indicate that the neutron detection response of the fibers is superior to the response with fibers drawn from the original terbium-doped glass. The new fibers offer less attenuation (1/e length of ∝40 cm) and improved gamma ray/neutron discrimination. The improved fibers will be incorporated in a scintillator fiber optic long counter for neutron detection. (orig.)

  1. Continuing Studies on Lead/Scintillating Fibres Calorimetry (LFC)

    CERN Multimedia

    2002-01-01

    Starting from the results obtained in the framework of the LAA Project~2B, we propose a continuation of the R&D on lead/scintillating fibres calorimetry (``spaghetti calorimetry''), including further tests on the old calorimeter prototypes and the construction and testing of new prototypes. The main results we pursue concern the performances of a projective calorimeter built with new, cheaper, techniques and the radiation hardness of the scintillating fibres, the optimization of a preshower detector system is also studied.

  2. Head-positioning scintillation camera and head holder therefor

    International Nuclear Information System (INIS)

    Kay, T.D.

    1976-01-01

    A holder for immobilizing the head of a patient undergoing a vertex brain scan by a Gamma Scintillation Camera is described. The holder has a uniquely designed shape capable of comfortably supporting the head. In addition, this holder can be both adjustably and removably utilized in combination with the scintillation camera so as to enable the brain scan operation to take place while the patient is in the seated position

  3. Development of water radiocontamination monitor using a plastic scintillator detector

    International Nuclear Information System (INIS)

    Mesquita, C.H. de; Madi Filho, T.; Hamada, M.M.

    1990-01-01

    An alpha, beta and gamma radiation water monitor was developed using a plastic scintillator detector with a sensitivity level of 15 bplastic scintillator detector with a sensitivity level of 15 Bq.L -1 and a counting efficiency of 25% for 131 I. It was proposed to be used in the radiation monitoring program of the research reactor swimming-pool of Sao Paulo. A simplified design and some properties of this monitor are presented. (author) [pt

  4. PMP, a novel solute for liquid and plastic scintillation counting

    International Nuclear Information System (INIS)

    Gusten, Hans

    1983-01-01

    The excellent fluorescence properties of PMP ( 11-phenyl-3-mesityl-2-pyrazoline) such as long wavelength emission of over 400 nm, and high fluorescence quantum yield with a short decay time together with a solubility of more than one Mol/L in toluene make this compound a promising solute for scintillation counting. The Stokes' shift of PMP of over 10,000 cm -1 is twice as large as that of the commonly used PPO. Due to this unusually large Stokes' shift PMP can be used as a primary solute without requiring a secondary solute as wavelength shifter. A comparison of the scintillation properties of PMP and PPO in toluene reveals that the counting efficiency for 14 C is better for PMP while the 3 H efficiency is equally good. Due to the large Stokes' shift, PMP is about 50 percent less sensitive to color quenching than PPO. Compared to the solute combinations PPO/secondary solutes, the scintillation counting efficiency of PMP for 14 C in toluene or xylene is the same, while the absolute 3 H efficiency of PPO/secondary solutes in cocktails with emulsifiers is about 10 percent higher. The PMP scintillation efficiency for 14 C as well as 3 H in chemical quenching by urine is more or less the same as for PPO/dimethyl-POPOP. PMP is more sensitive to quenching by halogenated solvents. In the dioxane-based scintillation, this sensitivity to chemical quenching by CHCl 3 vanishes and the counting efficiencies for 14 C and 3 H are as good as for PPO/dimethyl-POPOP or PPO/bis-MSB. Due to the large Stokes' shift, the self-absorption of the scintillation light by PMP is lower than in conventional scintillators. This offers good possibilities in very large-volume applications of liquid as well as plastic scintillators

  5. Multiple event 2D image intensifier scintillation detector

    International Nuclear Information System (INIS)

    Thieberger, P.; Wegner, H.E.; Lee, R.C.

    1981-01-01

    An image intensifier scintillation detector has been developed for the simultaneous detection of multiple light or heavy ions down to very low energies. The relative X-Y positions of each ion are read out by digitization of a television image of the light amplified scintillations. The maximum data rate is limited by the present television scan speed to 15 multiple events per second and to about one event second by the microcomputer presently used to store and process the data. (orig.)

  6. A study of light collection efficiency in scintillation detectors

    International Nuclear Information System (INIS)

    Xiaoguang, Y.

    1984-01-01

    A group of computer programs was set up to study the light collection efficiency in scintillation detectors with rectangular cross sections. The input conditions can be chosen arbitrarily, including: the size, light attenuation length and refraction index of the scintillator and light guide, the refraction index of the coupling medium, the reflection characteristics of the walls, and the position of light sources. A few examples are discussed in this article. (orig.)

  7. Research to Operations of Ionospheric Scintillation Detection and Forecasting

    Science.gov (United States)

    Jones, J.; Scro, K.; Payne, D.; Ruhge, R.; Erickson, B.; Andorka, S.; Ludwig, C.; Karmann, J.; Ebelhar, D.

    Ionospheric Scintillation refers to random fluctuations in phase and amplitude of electromagnetic waves caused by a rapidly varying refractive index due to turbulent features in the ionosphere. Scintillation of transionospheric UHF and L-Band radio frequency signals is particularly troublesome since this phenomenon can lead to degradation of signal strength and integrity that can negatively impact satellite communications and navigation, radar, or radio signals from other systems that traverse or interact with the ionosphere. Although ionospheric scintillation occurs in both the equatorial and polar regions of the Earth, the focus of this modeling effort is on equatorial scintillation. The ionospheric scintillation model is data-driven in a sense that scintillation observations are used to perform detection and characterization of scintillation structures. These structures are then propagated to future times using drift and decay models to represent the natural evolution of ionospheric scintillation. The impact on radio signals is also determined by the model and represented in graphical format to the user. A frequency scaling algorithm allows for impact analysis on frequencies other than the observation frequencies. The project began with lab-grade software and through a tailored Agile development process, deployed operational-grade code to a DoD operational center. The Agile development process promotes adaptive promote adaptive planning, evolutionary development, early delivery, continuous improvement, regular collaboration with the customer, and encourage rapid and flexible response to customer-driven changes. The Agile philosophy values individuals and interactions over processes and tools, working software over comprehensive documentation, customer collaboration over contract negotiation, and responding to change over following a rigid plan. The end result was an operational capability that met customer expectations. Details of the model and the process of

  8. Progress in PbWO4 scintillating crystal

    International Nuclear Information System (INIS)

    Fyodorov, A.; Korzhik, M.; Missevitch, O.; Pavlenko, V.; Kachanov, V.; Singovsky, A.; Annenkov, A.N.; Ligun, V.A.; Peigneux, J.P.; Vialle, J.P.

    1994-12-01

    Lead tungstate PbWO 4 (PWO) has recently been shown to be a promising scintillating material for precise electromagnetic calorimetry. Modifications of PWO technology were made to improve the uniformity of the crystal properties. A model of the scintillation mechanism for PWO was developed and served to guide the improvement. The complex spectroscopic analysis of the crystal after improvement is presented, as well as the new crystal properties achieved. (K.A.). 14 refs., 14 figs., 4 tabs

  9. High effective atomic number polymer scintillators for gamma ray spectroscopy

    Science.gov (United States)

    Cherepy, Nerine Jane; Sanner, Robert Dean; Payne, Stephen Anthony; Rupert, Benjamin Lee; Sturm, Benjamin Walter

    2014-04-15

    A scintillator material according to one embodiment includes a bismuth-loaded aromatic polymer having an energy resolution at 662 keV of less than about 10%. A scintillator material according to another embodiment includes a bismuth-loaded aromatic polymer having a fluor incorporated therewith and an energy resolution at 662 keV of less than about 10%. Additional systems and methods are also presented.

  10. Fiber-optic multipoint radiation sensing system using waveguide scintillators

    International Nuclear Information System (INIS)

    Maekawa, Tatsuyuki; Yoda, Masaki; Tanaka, Koutarou; Masumaru, Tarou; Morimoto, Souichirou.

    1996-01-01

    Novel fiber-optic radiation sensors and a multipoint measurement method that takes advantage of them have been developed. The new sensor design, which we call a 'waveguide scintillator', consists of a scintillating material and a wavelength-shifting fiber (WLSF). The WLSF is embedded in the scintillating material, and each end is connected to a transparent optical fiber. These waveguide scintillators can be connected in series along an optical fiber loop to form a radiation monitoring system, and each end of the fiber loop is terminated with a photodetector. This new radiation monitoring arrangement dispenses with the need for electronic apparatus at each measuring point and consequently improves resistance to noise. Furthermore, it offers the advantages of multipoint monitoring - meaning that radiation intensity can be measured at multiple sensors - using only two photodetectors. We have examined the light output characteristics and time resolution of a prototype arrangement of these new waveguide scintillators, thus confirming the feasibility of multipoint measurements using a system of multiple waveguide scintillators connected in series in an optical fiber loop. (author)

  11. Detection of gamma rays using scintillation optical fibers

    International Nuclear Information System (INIS)

    Park, J. W.; Hong, S. B.

    2002-01-01

    Scintillating optical fibers have several advantages over other conventional materials used for radiation detection. We have used glass and plastic scintillating fibers to detect gamma rays emitted from 60 Co and 137 Cs, and beta rays from 90 Sr. The sensors are constructed of single strand or multi-strand fibers of 1 mm diameter. The glass scintillating fiber used contains cerium-activated lithium-silicate as scintillating material and the plastic scintillating fiber used is Bicron model BCF-12. In this paper, we report the pulse-height spectra obtained by both sensor types, and analyze them in the aspect of their usability for radiation detectors. Our investigation suggests that the glass fiber can be used to develop gamma ray detectors which will function in high and low gamma ray flux environments. Use of the sensor for the beta ray detection was not satisfactory. The plastic fiber sensor did not work satisfactorily for the weak gamma sources, but did produce somewhat promising results. The scintillating plastic fiber offers some feasibility as beta ray sensor material

  12. Red Emitting Phenyl-Polysiloxane Based Scintillators for Neutron Detection

    International Nuclear Information System (INIS)

    Dalla Palma, Matteo; Quaranta, Alberto; Marchi, Tommaso; Gramegna, Fabiana; Cinausero, Marco; Carturan, Sara; Collazuol, Gianmaria

    2013-06-01

    In this work, the performances of new red emitting phenyl- substituted polysiloxane based scintillators are described. Three dyes were dispersed in a phenyl-polysiloxane matrix in order to shift the scintillation wavelength towards the red part of the visible spectrum. PPO, Lumogen Violet (BASF) and Lumogen Red (BASF) were mixed to the starting resins with different wt. % and the analysis of the different samples was performed by means of fluorescence measurements. The scintillation yield to alpha particles at the different dye ratios was monitored by detecting either the full spectrum or the red part of the emitted light. Finally, thin red scintillators with selected compositions were coupled to Avalanche Photodiode sensors, which are usually characterized by higher efficiency in the red part of the spectrum. An increased light output of about 17% has been obtained comparing the red scintillators to standard blue emitting systems. Preliminary results on the detection of fast neutrons with the APD-red scintillator system are also presented. (authors)

  13. A different approach to the analysis of GPS scintillations data

    International Nuclear Information System (INIS)

    Forte, B.; Radicella, S.M.; Ezquer, R.G.

    2001-09-01

    Amplitude scintillations data from GPS have been analyzed. The objective is to estimate the impact of ionospheric scintillations at Satellite-Based Augmentation System (SBAS) Ranging and Integrity Monitoring Station (RIMS) level and at GPS user level. For this purpose a new approach to the problem has been considered. Data have been studied from the point of view of the impact of scintillations on the calculation of VTEC at pierce points and ionospheric grid points. An ionospheric grid of 5 deg. by 5 deg. surface squares has been assumed. From geometrical considerations and taking into account the basic principle to compute VTEC at grid points, with the data analyzed it is shown that very seldom scintillations can affect the calculation of a grid point VTEC. Data from all the RIMS and for the entire GPS satellites network must be analyzed simultaneously to describe a realistic scenario for the impact of scintillations on SBAS. Finally, GPS scintillation data have been analyzed at user level: service availability problems have been encountered. (author)

  14. Alpha/beta pulse shape discrimination in plastic scintillation using commercial scintillation detectors

    International Nuclear Information System (INIS)

    Bagan, H.; Tarancon, A.; Rauret, G.; Garcia, J.F.

    2010-01-01

    Activity determination in different types of samples is a current need in many different fields. Simultaneously analysing alpha and beta emitters is now a routine option when using liquid scintillation (LS) and pulse shape discrimination. However, LS has an important drawback, the generation of mixed waste. Recently, several studies have shown the capability of plastic scintillation (PS) as an alternative to LS, but no research has been carried out to determine its capability for alpha/beta discrimination. The objective of this study was to evaluate the capability of PS to discriminate alpha/beta emitters on the basis of pulse shape analysis (PSA). The results obtained show that PS pulses had lower energy than LS pulses. As a consequence, a lower detection efficiency, a shift to lower energies and a better discrimination of beta and a worst discrimination of alpha disintegrations was observed for PS. Colour quenching also produced a decrease in the energy of the particles, as well as the effects described above. It is clear that in PS, the discrimination capability was correlated with the energy of the particles detected. Taking into account the discrimination capabilities of PS, a protocol for the measurement and the calculation of alpha and beta activities in mixtures using PS and commercial scintillation detectors has been proposed. The new protocol was applied to the quantification of spiked river water samples containing a pair of radionuclides ( 3 H- 241 Am or 90 Sr/ 90 Y- 241 Am) in different activity proportions. The relative errors in all determinations were lower than 7%. These results demonstrate the capability of PS to discriminate alpha/beta emitters on the basis of pulse shape and to quantify mixtures without generating mixed waste.

  15. Influence of coma aberration on aperture averaged scintillations in oceanic turbulence

    Science.gov (United States)

    Luo, Yujuan; Ji, Xiaoling; Yu, Hong

    2018-01-01

    The influence of coma aberration on aperture averaged scintillations in oceanic turbulence is studied in detail by using the numerical simulation method. In general, in weak oceanic turbulence, the aperture averaged scintillation can be effectively suppressed by means of the coma aberration, and the aperture averaged scintillation decreases as the coma aberration coefficient increases. However, in moderate and strong oceanic turbulence the influence of coma aberration on aperture averaged scintillations can be ignored. In addition, the aperture averaged scintillation dominated by salinity-induced turbulence is larger than that dominated by temperature-induced turbulence. In particular, it is shown that for coma-aberrated Gaussian beams, the behavior of aperture averaged scintillation index is quite different from the behavior of point scintillation index, and the aperture averaged scintillation index is more suitable for characterizing scintillations in practice.

  16. Investigation on neutron/gamma discrimination phenomena in plastic scintillators

    International Nuclear Information System (INIS)

    Blanc, Pauline

    2014-01-01

    This PhD topic was born from misunderstandings and incomplete knowledge of the mechanism and relative effectiveness of neutron and gamma-ray (n/γ) discrimination between plastic scintillators compared to liquid scintillators. The shape of the light pulse these materials generate following interaction with an ionizing particle (predominantly recoil protons in the case of neutrons and electrons in the case of gamma-rays) is different in time in a way that depends on the detected particle (nature and energy). It is this fact that enables separation (PSD). The behavior in liquid scintillators has been extensively studied experimentally for practical applications. Only recently has it been shown that a weak separation can also be achieved using specially prepared plastics. The study of this system presents an open field and the understanding of both liquids and plastics with respect to their PSD properties is far from complete. This work is dedicated to exploring the fundamental photophysical phenomena at play in the generation of luminescence emission, following the interaction of ionizing radiation with organic scintillators. For this purpose, firstly a detailed literature review of the state-of-the-art has been conducted extending from 1960 to the present day. Secondly a complete characterization of the main scintillating materials has been conducted to define their fluorescence properties and the characteristics of their scintillation under irradiation. Thirdly a proton beam has been used to simulate recoil protons to quantify under controlled laboratory conditions their specific energy deposition in a plastic scintillator with PSD properties. The fourth part of this thesis is devoted to the study of PSD efficiency of scintillators as a function of their molecular structure. This investigation has led to a plastic scintillator prepared in our laboratory with good PSD properties and a patent submission. Finally, photophysical experiments were performed using a

  17. Scintillation neutron detector with dynamic threshold

    International Nuclear Information System (INIS)

    Kornilov, N.; Massey, T.; Grimes, S.

    2014-01-01

    Scintillation neutron detectors with hydrogen are a common tool for neutron spectroscopy. They provide good time resolution, neutron-gamma discrimination and high efficiency of neutron counting. The real open problems connected with application of these detectors are in the energy range >10 MeV. There are no standard neutron spectra known with high accuracy for this energy range. Therefore, traditional methods for experimental investigation of the efficiency function fail for these neutrons. The Monte Carlo simulation cannot provide reasonable accuracy due to unknown characteristics of the reactions for charged particle production (p, α and so on, light output, reaction cross-sections). The application of fission chamber with fissile material as a neutron detector did not help to solve the problem. We may avoid many problems if we use the traditional neutron detector with non-traditional data analysis. In this report we give main relations, and demonstrate the method for Cf-source. Experimental detector efficiency is compared with MC simulation. (authors)

  18. Liquid Scintillation High Resolution Spectral Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Grau Carles, A.; Grau Malonda, A.

    2010-08-06

    The CIEMAT/NIST and the TDCR methods in liquid scintillation counting are based on the determination of the efficiency for total counting. This paper tries to expand these methods analysing the pulse-height spectrum of radionuclides. To reach this objective we have to generalize the equations used in the model and to analyse the influence of ionization and chemical quench in both spectra and counting efficiency. We present equations to study the influence of different photomultipliers response in systems with one, two or three photomultipliers. We study the effect of the electronic noise discriminator level in both spectra and counting efficiency. The described method permits one to study problems that up to now was not possible to approach, such as the high uncertainty in the standardization of pure beta-ray emitter with low energy when we apply the TDCR method, or the discrepancies in the standardization of some electron capture radionuclides, when the CIEMAT/NIST method is applied. (Author) 107 refs.

  19. Lutetium oxide-based transparent ceramic scintillators

    Science.gov (United States)

    Seeley, Zachary; Cherepy, Nerine; Kuntz, Joshua; Payne, Stephen A.

    2016-01-19

    In one embodiment, a transparent ceramic of sintered nanoparticles includes gadolinium lutetium oxide doped with europium having a chemical composition (Lu.sub.1-xGd.sub.x).sub.2-YEu.sub.YO.sub.3, where X is any value within a range from about 0.05 to about 0.45 and Y is any value within a range from about 0.01 to about 0.2, and where the transparent ceramic exhibits a transparency characterized by a scatter coefficient of less than about 10%/cm. In another embodiment, a transparent ceramic scintillator of sintered nanoparticles, includes a body of sintered nanoparticles including gadolinium lutetium oxide doped with a rare earth activator (RE) having a chemical composition (Lu.sub.1-xGd.sub.x).sub.2-YRE.sub.YO.sub.3, where RE is selected from the group consisting of: Sm, Eu, Tb, and Dy, where the transparent ceramic exhibits a transparency characterized by a scatter coefficient of less than about 10%/cm.

  20. Predicting Pulsar Scintillation from Refractive Plasma Sheets

    Science.gov (United States)

    Simard, Dana; Pen, Ue-Li

    2018-05-01

    The dynamic and secondary spectra of many pulsars show evidence for long-lived, aligned images of the pulsar that are stationary on a thin scattering sheet. One explanation for this phenomenon considers the effects of wave crests along sheets in the ionized interstellar medium, such as those due to Alfvén waves propagating along current sheets. If these sheets are closely aligned to our line-of-sight to the pulsar, high bending angles arise at the wave crests and a selection effect causes alignment of images produced at different crests, similar to grazing reflection off of a lake. Using geometric optics, we develop a simple parameterized model of these corrugated sheets that can be constrained with a single observation and that makes observable predictions for variations in the scintillation of the pulsar over time and frequency. This model reveals qualitative differences between lensing from overdense and underdense corrugated sheets: Only if the sheet is overdense compared to the surrounding interstellar medium can the lensed images be brighter than the line-of-sight image to the pulsar, and the faint lensed images are closer to the pulsar at higher frequencies if the sheet is underdense, but at lower frequencies if the sheet is overdense.

  1. Liquid Scintillation High Resolution Spectral Analysis

    International Nuclear Information System (INIS)

    Grau Carles, A.; Grau Malonda, A.

    2010-01-01

    The CIEMAT/NIST and the TDCR methods in liquid scintillation counting are based on the determination of the efficiency for total counting. This paper tries to expand these methods analysing the pulse-height spectrum of radionuclides. To reach this objective we have to generalize the equations used in the model and to analyse the influence of ionization and chemical quench in both spectra and counting efficiency. We present equations to study the influence of different photomultipliers response in systems with one, two or three photomultipliers. We study the effect of the electronic noise discriminator level in both spectra and counting efficiency. The described method permits one to study problems that up to now was not possible to approach, such as the high uncertainty in the standardization of pure beta-ray emitter with low energy when we apply the TDCR method, or the discrepancies in the standardization of some electron capture radionuclides, when the CIEMAT/NIST method is applied. (Author) 107 refs.

  2. A scintillation detector signal processing technique with active pileup prevention for extending scintillation count rates

    International Nuclear Information System (INIS)

    Wong, W.H.; Li, H.

    1998-01-01

    A new method for processing signals from scintillation detectors is proposed for very high count-rate situations where multiple-event pileups are the norm. This method is designed to sort out and recover every impinging event from multiple-event pileups while maximizing the collection of scintillation signal for every event to achieve optimal accuracy in determining the energy of the event. For every detected event, this method cancels the remnant signals from previous events, and excludes the pileup of signals from following events. With this technique, pileup events can be recovered and the energy of every recovered event can be optimally measured despite multiple pileups. A prototype circuit demonstrated that the maximum count rates have been increased by more than 10 times, comparing to the standard pulse-shaping method, while the energy resolution is as good as that of the pulse shaping (or the fixed integration) method at normal count rates. At 2 x 10 6 events/sec for NaI(Tl), the true counts acquired are 3 times more than the delay-line clipping method (commonly used in fast processing designs) due to events recovered from pileups. Pulse-height spectra up to 3.5 x 10 6 events/sec have been studied

  3. Research in high energy physics: Scintillating fiber detector development for the SSC: Annual progress report

    International Nuclear Information System (INIS)

    Ruchti, R.C.

    1988-01-01

    The scintillating fiber detector development program at the University of Notre Dame is divided into several components. These include: Research on scintillating glass fiber materials; Research on scintillating plastic fiber materials; Research on scintillating liquids in fiber capillaries; Studies of improvements in image intensification and light amplification of appropriate test and development facilities at Notre Dame. The overall goal of the program is to develop efficient scintillating fiber detectors with long, optical attenuation length, and excellent radiation resistance properties for tracking and microvertex detectors and as component active sampling materials for scintillation calorimetry. We now discuss each of these programs in turn. 2 figs., 3 tabs

  4. Scintillation properties of polycrystalline LaxY1-xO3 ceramic

    Science.gov (United States)

    Sahi, Sunil; Chen, Wei; Kenarangui, Rasool

    2015-03-01

    Scintillators are the material that absorbs the high-energy photons and emits visible photons. Scintillators are commonly used in radiation detector for security, medical imaging, industrial applications and high energy physics research. Two main types of scintillators are inorganic single crystals and organic (plastic or liquid) scintillators. Inorganic single crystals are expensive and difficult to grow in desire shape and size. Also, some efficient inorganic scintillator such as NaI and CsI are not environmental friendly. But on the other hand, organic scintillators have low density and hence poor energy resolution which limits their use in gamma spectroscopy. Polycrystalline ceramic can be a cost effective alternative to expensive inorganic single crystal scintillators. Here we have fabricated La0.2Y1.8O3 ceramic scintillator and studied their luminescence and scintillation properties. Ceramic scintillators were fabricated by vacuum sintering of La0.2Y1.8O3 nanoparticles at temperature below the melting point. La0.2Y1.8O3 ceramic were characterized structurally using XRD and TEM. Photoluminescence and radioluminescence studies were done using UV and X-ray as an excitation source. We have used gamma isotopes with different energy to studies the scintillation properties of La0.2Y1.8O3 scintillator. Preliminary studies of La0.2Y1.8O3 scintillator shows promising result with energy resolution comparable to that of NaI and CsI.

  5. Transparent plastic scintillators for neutron detection based on lithium salicylate

    International Nuclear Information System (INIS)

    Mabe, Andrew N.; Glenn, Andrew M.; Carman, M. Leslie; Zaitseva, Natalia P.; Payne, Stephen A.

    2016-01-01

    Transparent plastic scintillators with pulse shape discrimination containing "6Li salicylate have been synthesized by bulk polymerization with a maximum "6Li loading of 0.40 wt%. Photoluminescence and scintillation responses to gamma-rays and neutrons are reported herein. Plastics containing "6Li salicylate exhibit higher light yields and permit a higher loading of "6Li as compared to previously reported plastics based on lithium 3-phenylsalicylate. However, pulse shape discrimination performance is reduced in lithium salicylate plastics due to the requirement of adding more nonaromatic monomers to the polymer matrix as compared to those based on lithium 3-phenylsalicylate. Reduction in light yield and pulse shape discrimination performance in lithium-loaded plastics as compared to pulse shape discrimination plastics without lithium is interpreted in terms of energy transfer interference by the aromatic lithium salts. - Highlights: • Plastic scintillator with 0.4% "6Li loading is reported using lithium salicylate. • Influence of lithium salts on the scintillation mechanism is explored. • New lithium-loaded scintillator provides improved light yield and reduced cost.

  6. Ionosphere Scintillation at Low and High Latitudes (Modelling vs Measurement)

    Science.gov (United States)

    Béniguel, Yannick

    2016-04-01

    This paper will address the problem of scintillations characteristics, focusing on the parameters of interest for a navigation system. Those parameters are the probabilities of occurrence of simultaneous fading, the bubbles surface at IPP level, the cycle slips and the fades duration statistics. The scintillation characteristics obtained at low and high latitudes will be compared. These results correspond to the data analysis performed after the ESA Monitor ionosphere measurement campaign [1], [2]. A second aspect of the presentation will be the modelling aspect. It has been observed that the phase scintillation dominates at high latitudes while the intensity scintillation dominates at low latitudes. The way it can be reproduced and implemented in a propagation model (e.g. GISM model [3]) will be presented. Comparisons of measurements with results obtained by modelling will be presented on some typical scenarios. References [1] R. Prieto Cerdeira, Y. Beniguel, "The MONITOR project: architecture, data and products", Ionospheric Effects Symposium, Alexandria (Va), May 2011 [2] Y. Béniguel, R Orus-Perez , R. Prieto-Cerdeira , S. Schlueter , S. Scortan, A. Grosu "MONITOR 2: ionospheric monitoring network in support to SBAS and other GNSS and scientific purposes", IES Conference, Alexandria (Va), May 2015-05-22 [3] Y. Béniguel, P. Hamel, "A Global Ionosphere Scintillation Propagation Model for Equatorial Regions", Journal of Space Weather Space Climate, 1, (2011), doi: 10.1051/swsc/2011004

  7. Low cost plastic scintillator by using commercial polystyrene

    International Nuclear Information System (INIS)

    Oktar, O.; Ari, G.; Guenduez, O.; Demirel, H.; Demirbas, A.

    2009-01-01

    Plastic scintillation detectors have been used in nuclear and high energy physics for many decades. Among their benefits are fast response, ease of manufacture and versatility. Their main drawbacks are radiation resistance and cost. Plastic Scintillators can be described as solid materials which contain organic fluorescent compounds dissolved within a polymer matri10. Transparent plastics commonly used for light scintillation are Polystyrene (or PS, poly-vinyl-benzene) and polyvinyl-toluene (or PVT, poly-methyl-styron). In this activity, preliminary studies for low cost plastic scintillator production by using commercial polystyrene pellets and extrusion method were aimed. For this purpose, PS blocks consist of commercial fluorescent dopant were prepared by an extruder in SANAEM. Molds suitable for extruder were designed and manufactured and optimum production parameters such as extrusion temperature profile, extrusion rate and pressure were obtained. Plastic blocks prepared were optically and mechanically tested and its response against various radioactive sources was measured.This study has shown that plastic scintillators imported can be produced in SANAEM domestically and be used for detection of radioactive materials within the country or border gates.

  8. Irregular ionization and scintillation of the ionosphere in equator region

    International Nuclear Information System (INIS)

    Shinno, Kenji

    1974-01-01

    The latest studies on the scintillation in satellite communication and its related irregularities of ionosphere are reviewed. They were made clear by means of spread-F, the direct measurement with scientific satellites, VHF radar observation, and radio wave propagation in equator region. The fundamental occurrence mechanism may be instability of plasma caused by the interaction of movement of neutral atmosphere and magnetic field. Comparison of the main characteristics of scintillation, namely the dependence on region, solar activity, season, local time, geomagnetic activity, movement in ionosphere, scattering source, frequency and transmission mode, was made and the correlation among spread-F, TEP and scintillation was summarized. The latest principal studies were the observations made by Intelsat and by ATS. Scintillation of Syncom-3 and Intelsat-II-F2 and spread-F by ionosphere observation were compared by Huang. It is reasonable to consider that the occurrence of scintillation is caused by the irregularities in ionosphere which are particular in equator region, because of the similar characteristics of spread-F and VHF propagation in the equator region. These three phenomena may occur in relation to the irregularities of ionosphere. Interpretation of spread-F and the abnormal propagation wave across the equator are given. The study using VHF radar and the movement of irregular ionization by the direct observation with artificial satellites are reviewd. (Iwakiri, K.)

  9. Performance of Water-Based Liquid Scintillator: An Independent Analysis

    Directory of Open Access Journals (Sweden)

    D. Beznosko

    2014-01-01

    Full Text Available The water-based liquid scintillator (WbLS is a new material currently under development. It is based on the idea of dissolving the organic scintillator in water using special surfactants. This material strives to achieve the novel detection techniques by combining the Cerenkov rings and scintillation light, as well as the total cost reduction compared to pure liquid scintillator (LS. The independent light yield measurement analysis for the light yield measurements using three different proton beam energies (210 MeV, 475 MeV, and 2000 MeV for water, two different WbLS formulations (0.4% and 0.99%, and pure LS conducted at Brookhaven National Laboratory, USA, is presented. The results show that a goal of ~100 optical photons/MeV, indicated by the simulation to be an optimal light yield for observing both the Cerenkov ring and the scintillation light from the proton decay in a large water detector, has been achieved.

  10. Gadolinium-loaded gel scintillators for neutron and antineutrino detection

    Science.gov (United States)

    Riddle, Catherine Lynn; Akers, Douglas William; Demmer, Ricky Lynn; Paviet, Patricia Denise; Drigert, Mark William

    2016-11-29

    A gadolinium (Gd) loaded scintillation gel (Gd-ScintGel) compound allows for neutron and gamma-ray detection. The unique gel scintillator encompasses some of the best features of both liquid and solid scintillators, yet without many of the disadvantages associated therewith. Preferably, the gel scintillator is a water soluble Gd-DTPA compound and water soluble fluorophores such as: CdSe/ZnS (or ZnS) quantum dot (Q-dot) nanoparticles, coumarin derivatives 7-hydroxy-4-methylcoumarin, 7-hydroxy-4-methylcoumarin-3-acetic acid, 7-hydroxycoumarin-3-carboxylic acid, and Alexa Fluor 350 as well as a carbostyril compound, carbostyril 124 in a stable water-based gel, such as methylcellulose or polyacrylamide polymers. The Gd-loaded ScintGel allows for a homogenious distribution of the Gd-DTPA and the fluorophores, and yields clean fluorescent emission peaks. A moderator, such as deuterium or a water-based clear polymer, can be incorporated in the Gd-ScintGel. The gel scintillators can be used in compact detectors, including neutron and antineutrino detectors.

  11. Scintillation properties of CdF{sub 2} crystal

    Energy Technology Data Exchange (ETDEWEB)

    Yanagida, Takayuki, E-mail: yanagida@lsse.kyutech.ac.jp [Kyushu Institute of Technology, 2-4 Hibikino, Wakamatsu, Kitakyushu, Fukuoka 808-0196 (Japan); Fujimoto, Yutaka; Koshimizu, Masanori [Department of Applied Chemistry, Graduate School of Engineering, Tohoku University, 6-6-07 Aoba, Aramaki, Aoba-ku, Sendai 980-8579 (Japan); Fukuda, Kentaro [Tokuyama Corp., 1-1 Mikage-cho, Shunan-shi, Yamaguchi 745-8648 Japan (Japan)

    2015-01-15

    CdF{sub 2} single crystal was prepared by Tokuyama Corp. with the μ-PD method to investigate Auger free luminescence of this material. From optical transmittance spectrum, bandgap wavelength was around 280 nm. In X-ray induced radioluminescence spectrum, emission lines appeared around 350 nm and 420 nm. Excitation wavelength was investigated and excitation peak was around 250 nm. Photoluminescence and scintillation decay times were evaluated and decay time was few ns. Temperature dependence of X-ray induced radioluminescence was compared with conventional BaF{sub 2} scintillator and scintillation of CdF{sub 2} decreased when the temperature increased. Consequently, scintillation of CdF{sub 2} is possibly emission at color centers or exciton related one. - Highlights: • CdF{sub 2} crystal scinitillator was synthesized. • Emission wavelengths of CdF{sub 2} appeared around 350 and 420 nm. • Scintillation decay time of CdF{sub 2} was quite fast, 1.75 ns. • Excitation bands were investigated by using Synchrotron facility, UVSOR.

  12. Scintillation properties of CdF2 crystal

    International Nuclear Information System (INIS)

    Yanagida, Takayuki; Fujimoto, Yutaka; Koshimizu, Masanori; Fukuda, Kentaro

    2015-01-01

    CdF 2 single crystal was prepared by Tokuyama Corp. with the μ-PD method to investigate Auger free luminescence of this material. From optical transmittance spectrum, bandgap wavelength was around 280 nm. In X-ray induced radioluminescence spectrum, emission lines appeared around 350 nm and 420 nm. Excitation wavelength was investigated and excitation peak was around 250 nm. Photoluminescence and scintillation decay times were evaluated and decay time was few ns. Temperature dependence of X-ray induced radioluminescence was compared with conventional BaF 2 scintillator and scintillation of CdF 2 decreased when the temperature increased. Consequently, scintillation of CdF 2 is possibly emission at color centers or exciton related one. - Highlights: • CdF 2 crystal scinitillator was synthesized. • Emission wavelengths of CdF 2 appeared around 350 and 420 nm. • Scintillation decay time of CdF 2 was quite fast, 1.75 ns. • Excitation bands were investigated by using Synchrotron facility, UVSOR

  13. Use of internal scintillator radioactivity to calibrate DOI function of a PET detector with a dual-ended-scintillator readout

    International Nuclear Information System (INIS)

    Bircher, Chad; Shao Yiping

    2012-01-01

    Purpose: Positron emission tomography (PET) detectors that use a dual-ended-scintillator readout to measure depth-of-interaction (DOI) must have an accurate DOI function to provide the relationship between DOI and signal ratios to be used for detector calibration and recalibration. In a previous study, the authors used a novel and simple method to accurately and quickly measure DOI function by irradiating the detector with an external uniform flood source; however, as a practical concern, implementing external uniform flood sources in an assembled PET system is technically challenging and expensive. In the current study, therefore, the authors investigated whether the same method could be used to acquire DOI function from scintillator-generated (i.e., internal) radiation. The authors also developed a method for calibrating the energy scale necessary to select the events within the desired energy window. Methods: The authors measured the DOI function of a PET detector with lutetium yttrium orthosilicate (LYSO) scintillators. Radiation events originating from the scintillators' internal Lu-176 beta decay were used to measure DOI functions which were then compared with those measured from both an external uniform flood source and an electronically collimated external point source. The authors conducted these studies with several scintillators of differing geometries (1.5 x 1.5 and 2.0 x 2.0 mm 2 cross-section area and 20, 30, and 40 mm length) and various surface finishes (mirror-finishing, saw-cut rough, and other finishes in between), and in a prototype array. Results: All measured results using internal and external radiation sources showed excellent agreement in DOI function measurement. The mean difference among DOI values for all scintillators measured from internal and external radiation sources was less than 1.0 mm for different scintillator geometries and various surface finishes. Conclusions: The internal radioactivity of LYSO scintillators can be used to

  14. Optimum plastic scintillator and optical fiber combination for brachytherapy dosimetry

    International Nuclear Information System (INIS)

    Arnfield, Mark R.; Gaballa, Hani E.; Zwicker, Robert D.; Islam, Quazi; Schmidt-Ullrich, Rupert

    1995-01-01

    Purpose/Objective: There have been several recent reports using plastic scintillators to measure dose in photon and electron beams. External beam measurements agreed well with standard ion chamber dosimetry. This was implemented by using two identical, parallel optical fibers with a small piece of plastic scintillator attached to one. We have constructed a similar device for application to brachytherapy. Brachytherapy dosimetry is a more difficult problem than external beam because of high dose gradients and widely ranging photon energies. Based on detailed spectral measurements, we have designed a dosimeter specifically to meet the unique, stringent needs of brachytherapy. Materials and Methods: The work consisted of two stages. In the first stage, we measured the optical spectra emitted by commercial plastic scintillators and silica core optical fibers in the presence of a 10 Curie iridium 192 HDR source. In the second stage, the spectral information was used to select an optimum combination of scintillator and fiber which were incorporated in the dosimeter. Equipment for the spectral measurements included a 0.1 meter monochromator with a sensitive photomultiplier (PMT) with flat response across the visible. The resolution of spectral scans was 4 nm. The dosimeter was constructed with a 1mm x 3mm piece of plastic scintillator bonded with optical cement to a 0.6 mm diameter silica core optical fiber. A second, identical optical fiber running alongside the first, with no scintillator attached, was used for background subtraction. Two PMTs with high sensitivity in the visible were used at the fiber distal ends. There was a space for an optical filter between the fiber and the PMTs, whose purpose is described below. The PMTs were connected to a differential pair whose output was transferred to a current source for measurement by a standard electrometer. Results: The scintillation spectra of six different types of silica core optical fibers in the presence of the

  15. Preparation and characterization of a novel UV-curable plastic scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Jun [Engineering Research Center of High Performance Polymer and Molding Technology, Ministry of Education, Qingdao University of Science and Technology, Qingdao 266042 (China); Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology and Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621010 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Ding, Yunyu [Engineering Research Center of High Performance Polymer and Molding Technology, Ministry of Education, Qingdao University of Science and Technology, Qingdao 266042 (China); Zhu, Jiayi [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Qi, Di [Engineering Research Center of High Performance Polymer and Molding Technology, Ministry of Education, Qingdao University of Science and Technology, Qingdao 266042 (China); Su, Ming [Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China); Xu, Yewei; Bi, Yutie [Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology and Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621010 (China); Lin, Runxiong, E-mail: qdlrx@qust.edu.cn [Engineering Research Center of High Performance Polymer and Molding Technology, Ministry of Education, Qingdao University of Science and Technology, Qingdao 266042 (China); Zhang, Lin, E-mail: zhlmy@sina.com [Joint Laboratory for Extreme Conditions Matter Properties, Southwest University of Science and Technology and Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621010 (China); Research Center of Laser Fusion, China Academy of Engineering Physics, Mianyang 621900 (China)

    2016-05-01

    A novel UV-curable plastic scintillator was first prepared by using the technology of photosensitivity rapid prototyping. It used the copolymer of 621A-80, TPGDA and styrene as the matrix doped with PPO and POPOP. Its fluorescence spectra displayed a maximum emission wavelength at 428 nm. The light yield of the plastic scintillator was approximately 7.1% of anthracene on the basis of a comparison with the commercially available scintillator (ST-401). The as-prepared plastic scintillator also displayed a fast scintillation decay. Its decay time is 2.6 ns approximately. Importantly, through the technology of photosensitivity rapid prototyping, the plastic scintillator could be prepared in a short period of time at low temperature. What's more, this preparation method provides the possibility of combining the plastic scintillator with 3D printing technology, and then the applications of the plastic scintillator may be expanded greatly.

  16. GNSS-based Observations and Simulations of Spectral Scintillation Indices in the Arctic Ionosphere

    DEFF Research Database (Denmark)

    Durgonics, Tibor; Hoeg, Per; von Benzon, Hans-Henrik

    During disturbed times, ionospheric scintillations can be severe and adversely impact satellite-based positioning and radio transmissions. The scintillation occurs in the amplitude, phase, polarization, and angle of arrival of the signal. Precise observation, classification, modeling, forecasting...

  17. Optimization of the wavelength shifter ratio in a polystyrene based plastic scintillator through energy spectrum analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ye Won; Kim, Myung Soo; Yoo, Hyun Jun; Lee, Dae Hee; Cho, Gyu Seong [Dept. of Nuclear and Quantum Engineering, KAIST, Daejeon (Korea, Republic of); Moon, Myung Kook [Neutron Instrumentation Division, Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2017-02-15

    The scintillation efficiency of the polystyrene based plastic scintillator depends on the ratio of the wavelength shifters, organic fluors (PPO and POPOP). Thus, 24 samples of the plastic scintillator were fabricated in order to find out the optimum ratio of the wavelength shifters in the plastic scintillator. The fabricated plastic scintillators were trimmed through a cutting and polishing process. They were used in gamma energy spectrum measurement with the {sup 137}Cs emitting monoenergy photon with 662 keV for the comparison of the scintillation efficiency. As a result, it was found out that the scintillator sample with 1.00 g of PPO (2,5-Diphenyloxazole) and 0.50 g of POPOP (1,4-Bis(5-phnyl-2oxidazolyl)benzene) dissolved in 100 g of styrene solution has the optimum ratio in terms of the light yield of the polystyrene based plastic scintillator.

  18. Prospects for first-principle calculations of scintillator properties

    International Nuclear Information System (INIS)

    Derenzo, Stephen E.; Weber, Marvin J.

    1999-01-01

    Several scintillation processes can be modeled from first principles using quantum chemistry cluster calculations and recently available high-performance computers. These processes include the formation of excitons and trapping centers, the diffusion of ionization energy (electrons and holes) through a host crystal, and the efficient capture of these carriers by an activator atom to form a luminous, non-quenched excited state. As examples of such calculations, results are presented for (1) hole transport in the known scintillator host crystal CsI, (2) hole trapping in the non-scintillator PbF 2 , (3) hole transport in the experimentally unexplored PbF 4 , and (4) the electronic nature of excited states of CsI : Tl and CsI : Na

  19. Simulation of light collection in calcium tungstate scintillation detectors

    Directory of Open Access Journals (Sweden)

    F. A. Danevich

    2015-12-01

    Full Text Available Due to high operational properties, the oxide scintillators are perspective for cryogenic scintillation experiments with aim of study rare nuclear processes. In order to optimize light yield and the energy resolution we performed calculations of the efficiency of light collection for different geometries of scintillation detector with CaWO4 crystal by Monte-Carlo method using Litrani, Geant4 and Zemax packages. The calculations were compared with experimental data in the same configurations, depending on the crystal shape, surface treatment, material and shape of the reflector and presence of optical contact. The best results were obtained with crystals shaped as the right prism with triangle base, with completely diffused surfaces, using mirror reflector shaped as a truncated cone. Simulations by using Litrani have shown the best agreement with experimental results.

  20. Scintillation Reduction using Conjugate-Plane Imaging (Abstract)

    Science.gov (United States)

    Vander Haagen, G. A.

    2017-12-01

    (Abstract only) All observatories are plagued by atmospheric turbulence exhibited as star scintillation or "twinkle" whether a high altitude adaptive optics research or a 30-cm amateur telescope. It is well known that these disturbances are caused by wind and temperature-driven refractive gradients in the atmosphere and limit the ultimate photometric resolution of land-based facilities. One approach identified by Fuchs (1998) for scintillation noise reduction was to create a conjugate image space at the telescope and focus on the dominant conjugate turbulent layer within that space. When focused on the turbulent layer little or no scintillation exists. This technique is described whereby noise reductions of 6 to 11/1 have been experienced with mathematical and optical bench simulations. Discussed is a proof-of-principle conjugate optical train design for an 80-mm, f7 telescope.