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Sample records for analysis photon activation

  1. Activation analysis using γ photons

    International Nuclear Information System (INIS)

    This report summarizes all the data required for using photonuclear reactions in the field of analysis. After a brief review of the elementary properties of nuclear reactions induced by photon irradiation, the main characteristics are given of high energy (E > 20 MeV) Bremsstrahlung sources. The principle of activation analysis based on the use of photons is given. Actual examples of the analytic possibilities are described in detail, in particular in the case of the determination of very small quantities (-6) of C, N, O and F. The influence of interfering nuclear reactions is discussed. (author)

  2. Standardizing Activation Analysis: New Software for Photon Activation Analysis

    International Nuclear Information System (INIS)

    Photon Activation Analysis (PAA) of environmental, archaeological and industrial samples requires extensive data analysis that is susceptible to error. For the purpose of saving time, manpower and minimizing error, a computer program was designed, built and implemented using SQL, Access 2007 and asp.net technology to automate this process. Based on the peak information of the spectrum and assisted by its PAA library, the program automatically identifies elements in the samples and calculates their concentrations and respective uncertainties. The software also could be operated in browser/server mode, which gives the possibility to use it anywhere the internet is accessible. By switching the nuclide library and the related formula behind, the new software can be easily expanded to neutron activation analysis (NAA), charged particle activation analysis (CPAA) or proton-induced X-ray emission (PIXE). Implementation of this would standardize the analysis of nuclear activation data. Results from this software were compared to standard PAA analysis with excellent agreement. With minimum input from the user, the software has proven to be fast, user-friendly and reliable.

  3. Apparatus for photon activation positron annihilation analysis

    Science.gov (United States)

    Akers, Douglas W.

    2007-06-12

    Non-destructive testing apparatus according to one embodiment of the invention comprises a photon source. The photon source produces photons having predetermined energies and directs the photons toward a specimen being tested. The photons from the photon source result in the creation of positrons within the specimen being tested. A detector positioned adjacent the specimen being tested detects gamma rays produced by annihilation of positrons with electrons. A data processing system operatively associated with the detector produces output data indicative of a lattice characteristic of the specimen being tested.

  4. Investigation of a medieval sword using photon activation analysis

    International Nuclear Information System (INIS)

    An ancient sword was examined for indications of forgery or, if authentic, any later processing or changes, e.g. replacement of parts of the weapon. Radiochemical as well as non-destructive analyses using high energy photon activation were used as analytical techniques. Metal parts of the hilt were analysed radiochemically and instrumentally whereas the blade was analysed non-destructively. Metallurgical investigations (hardness measurements, microstructure analysis) performed in parallel are also briefly described. No evidence of non-authenticity was found, which agrees well with the results of stylistical and weapon-scientific investigation carried out by an expert of ancient weaponry. (author) 20 refs.; 1 fig.; 2 tabs

  5. Some remarks on the state of photon activation analysis and the use of internal standards

    International Nuclear Information System (INIS)

    The status of photon activation analysis and the use of internal standards are reviewed. It is concluded that no fundamental innovations in photon activation analysis both in the analysis of light and heavier elements were reported in the literature. The existing procedures have been somewhat refined and the application spectrum enlarged. (author)

  6. A provenance study of coffee by photon activation analysis

    International Nuclear Information System (INIS)

    Photon activation analysis (PAA) is a multi-elemental radioanalytical technique in trace elements analysis with high accuracy and precision. Researchers at the Idaho accelerator center performed PAA analysis on coffee samples from several locations around the world as an initial step in assessing the relationship between trace elements in illicit drugs and the soils in which they were grown. The preliminary results show coffees from different locations have different concentrations of trace elements. In the three cases where we have soil samples, the matrices of elements in the coffee samples are closely related to the matrices of the elements of the local soil samples. The majority of trace elemental content is similar to that of the local soil sample in which the coffee is planted. It may be that coffee assimilates numerous elements from the soil where it is grown in similar ratios as is found in the soil. Thus, it is conceivable that the elemental content could serve as 'fingerprint' to trace the origins of the coffee. To verify our analytical results we applied X-ray fluorescence (XRF) methods as well. Our PAA results are consistent with XRF experimental data. The future of tracing the origin of illicit drugs with the PAA technique is promising. (author)

  7. Nondestructive multielemental analysis of ancient roman pottery using photon activation analysis techniques

    International Nuclear Information System (INIS)

    Several analytical methods were tested for the multiparameter-analysis of ancient roman pottery in order to elaborate a procedure for their identification. Main constituents, minor and trace-elements have been analyzed by high-energy photon activation analysis, followed by high resolution gamma spectroscopy. The environmental influence on the concentrations of the minor constituents and trace elements during deposition of the sherds in the soil has been examined. A comparison has been made between analysis data of ancient pottery obtained by photon activation analysis, X-ray fluorescence analysis and 14 MeV neutron activation analysis. Tables are given on the time dependence of the trace elements. The numerical data are summarized in several diagrams. (T.G.)

  8. Active Photonic Crystal Waveguides

    DEFF Research Database (Denmark)

    Ek, Sara

    This thesis deals with the fabrication and characterization of active photonic crystal waveguides, realized in III-V semiconductor material with embedded active layers. The platform offering active photonic crystal waveguides has many potential applications. One of these is a compact photonic...... crystal semiconductor optical amplier. As a step towards such a component, photonic crystal waveguides with a single quantum well, 10 quantum wells and three layers of quantum dots are fabricated and characterized. An experimental study of the amplied spontaneous emission and a implied transmission are...... presented in this thesis. A variation of photonic crystal design parameters are used leading to a spectral shift of the dispersion, it is veried that the observed effects shift accordingly. An enhancement of the amplified spontaneous emission was observed close to the band edge, where light is slowed down...

  9. Innovations at the MT 25 microtron aimed at applications in photon activation analysis

    Czech Academy of Sciences Publication Activity Database

    Krist, Pavel; Horák, Zbyněk; Mizera, Jiří; Chvátil, David; Vognar, Miroslav; Řanda, Zdeněk

    2015-01-01

    Roč. 304, č. 1 (2015), s. 183-188. ISSN 0236-5731 R&D Projects: GA ČR GA13-27885S; GA ČR(CZ) GBP108/12/G108 Institutional support: RVO:61389005 Keywords : microtron * electron accelerator * photon activation analysis * IPAA * short-lived radionuclides * pneumatic tube delivery system Subject RIV: BG - Nuclear , Atomic and Molecular Physics, Colliders Impact factor: 1.034, year: 2014

  10. Environmental monitoring near urban lead refineries by photon and neutron activation analysis

    International Nuclear Information System (INIS)

    Photon activation has been used in conjunction with neutron activation for multielement determinations in airborne particulates, soil, and hair samples collected near two secondary lead refineries in Metropolitan Toronto. Particle size distributions of suspended particulates collected with a high volume Andersen sampler are reported for Al, Sb, As, Br, Cl, Mn, Na, Pb, Ti and V. Increases in the concentrations of Pb, As and Sb associated with particles >3.3 μm diameter on certain days near the refineries has resulted in localized contamination as reflected in higher concentrations of these elements in soil. To assess Pb accumulation in local residents compared with control groups, approximately 250 hair samples were analyzed for Pb by photon activation analysis. Children living close to the refineries, especially boys, exhibit the most elevated levels: up to 20 times urban control values in some cases

  11. Statistical analysis on activation and photo-bleaching of step-wise multi-photon activation fluorescence of melanin

    Science.gov (United States)

    Gu, Zetong; Lai, Zhenhua; Zhang, Xi; Yin, Jihao; DiMarzio, Charles A.

    2015-03-01

    Melanin is regarded as the most enigmatic pigments/biopolymers found in most organisms. We have shown previously that melanin goes through a step-wise multi-photon absorption process after the fluorescence has been activated with high laser intensity. No melanin step-wise multi-photon activation fluorescence (SMPAF) can be obtained without the activation process. The step-wise multi-photon activation fluorescence has been observed to require less laser power than what would be expected from a non-linear optical process. In this paper, we examined the power dependence of the activation process of melanin SMPAF at 830nm and 920nm wavelengths. We have conducted research using varying the laser power to activate the melanin in a point-scanning mode for multi-photon microscopy. We recorded the fluorescence signals and position. A sequence of experiments indicates the relationship of activation to power, energy and time so that we can optimize the power level. Also we explored regional analysis of melanin to study the spatial relationship in SMPAF and define three types of regions which exhibit differences in the activation process.

  12. Determination of Interesting Toxicological Elements in PM2.5 by Neutron and Photon Activation Analysis

    Directory of Open Access Journals (Sweden)

    Pasquale Avino

    2013-01-01

    Full Text Available Human activities introduce compounds increasing levels of many dangerous species for environment and population. In this way, trace elements in airborne particulate have a preeminent position due to toxic element presence affecting the biological systems. The main problem is the analytical determination of such species at ultratrace levels: a very specific methodology is necessary with regard to the accuracy and precision and contamination problems. Instrumental Neutron Activation Analysis and Instrumental Photon Activation Analysis assure these requirements. A retrospective element analysis in airborne particulate collected in the last 4 decades has been carried out for studying their trend. The samples were collected in urban location in order to determine only effects due to global aerosol circulation; semiannual samples have been used to characterize the summer/winter behavior of natural and artificial origin. The levels of natural origin element are higher than those in other countries owing to geological and meteorological factors peculiar to Central Italy. The levels of artificial elements are sometimes less than those in other countries, suggesting a less polluted general situation for Central Italy. However, for a few elements (e.g., Pb the levels measured are only slight lower than those proposed as air ambient standard.

  13. Nondestructive assay of fluorine in geological and other materials by instrumental photon activation analysis with a microtron

    Czech Academy of Sciences Publication Activity Database

    Krausová, I.; Mizera, Jiří; Řanda, Z.; Chvátil, D.; Krist, P.

    2015-01-01

    Roč. 342, JAN (2015), s. 82-86. ISSN 0168-583X Institutional support: RVO:67985891 Keywords : fluorine * instrumental photon activation analysis * IPAA * coal Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.124, year: 2014

  14. Nondestructive assay of fluorine in geological and other materials by instrumental photon activation analysis with a microtron

    Czech Academy of Sciences Publication Activity Database

    Krausová, Ivana; Mizera, Jiří; Řanda, Zdeněk; Chvátil, David; Krist, Pavel

    2015-01-01

    Roč. 342, JAN (2015), s. 82-86. ISSN 0168-583X R&D Projects: GA ČR(CZ) GBP108/12/G108; GA ČR GA13-27885S Institutional support: RVO:61389005 Keywords : Fluorine * instrumental photon activation analysis * IPAA * coal Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 1.124, year: 2014

  15. Photonics activities at DTU Fotonik

    DEFF Research Database (Denmark)

    Jeppesen, Palle; Jepsen, Peter Uhd; Lodahl, Peter;

    2010-01-01

    DTU Fotonik, Department of Photonics Engineering at the Technical University of Denmark has about 200 employees including 60 PhD students. The ambition is to be among the world’s leading University departments within photonics research, education and innovation. To fulfil this ambition, DTU Fotonik...... tries to attract excellent researchers and students from all over the world and to collaborate with world leading research institutes and companies. The activities span from quantum photonics, nanotechnology and metamaterials over nonlinear fiber optics, optical sensors and diode lasers & LED systems to...

  16. Determination of selenium content of animal food-stuff using photon activation analysis

    International Nuclear Information System (INIS)

    By the use of isomeric activation (the reaction 77Se(γ, γ')sup(77m)Se) a rapid method is available for the determination and control of selenium content of samples of different origin. One mg of selenium can be determined with a relative error of 10% when the weight of sample is about 20 g. This sensitivity can be achieved easily using a 5-10 kCi cobalt-60 source. The analysis is carried out by the measurement of 160 keV gamma rays of sup(77m)Se with a physical half-life of 18 sec. (T.G.)

  17. Instrumental photon activation analysis of coal fly ashes using the internal standard method coupled with the standard addition method

    International Nuclear Information System (INIS)

    Multielement determinations of coal fly ashes (NIST SRM-1633a and BCR CRM-38) have been carried out by instrumental photon activation analysis using 30 MeV bremsstrahlung and the internal standard method coupled with the standard addition method. In these determinations, some major and minor constituent elements in the samples were properly used as effective internal standards. As a result, it was demonstrated that concentrations of 18 elements were determined accurately and precisely. Furthermore, a similar multielement determination has also been examined using 20 MeV bremsstrahlung. In this case, it was proved that better results can be achieved, because all interfering reactions were eliminated completely. (author) 14 refs.; 5 tabs

  18. Photon Factory activity report, 1990

    International Nuclear Information System (INIS)

    The Photon Factory has grown at a considerable rate, and 600 experiments are carried out in 1991, while the number of users is now 2300 including about 500 from industrial sectors. The use of synchrotron radiation increased from fundamental research to industrial development. The development at the Photon Factory is supported by the capability of the accelerators. At present, the 2.5 GeV PF ring is operated with positrons at the initial beam current of 350 mA. The total operation time was 3500 hours in the fiscal year 1990. The development of an avalanche mode photodiode, the observation of quantum beat in the experiment of nuclear Bragg scattering, the measurement of photo-electron and photo-ion spectroscopy were carried out. The conversion of TRISTAN main ring to an ultrahigh brilliance and high coherence source is planned for the future. The annual PF Symposium was held, and Professor H. Winick gave the lecture 'Ultrahigh brightness and coherent radiation from large storage rings'. In this report, the outline of the Photon Factory and the activities in Divisions of Injector Linac, Light Source and Instrumentation are described. (K.I.)

  19. Photon Factory Activity Report, 1994

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1995-12-31

    Photon Factory Activity Report no.12 deals with our activities in the period from October 1993 through September 1994. We operate two light sources at the Photon Factory; the 2.5-GeV Photon Factory storage ring, which is a dedicated light source, and the 6.5-GeV TRISTAN Accumulation Ring, which is parasitically used as a light source. We keep more than seventy experimental stations at two facilities, and accept experiments primarily according to approval by the Program Advisory Committee. The number of proposals to the Photon Factory has been still growing. Three-hundred eighty two proposals were approved by the PAC in FY1994, which is an increase by thirteen percent compared to the previous year. Remarkable was growth in biology proposals, particularly proposals in protein crystallography. In FY 1994, we accepted approximately 20,000 man-days as general users, and almost ten percent of them were from abroad. We always open the facility to users, not only domestic but also international. Recently we have been concentrating our effort to upgrading of the light sources and reconstruction of the experimental stations to keep the Photon Factory an attractive research facility in the forthcoming years. We have already started a program of reducing the emittance of the 2.5-GeV storage ring, which now operates with an emittance of 110 nm-rad, to 27 nm-rad by modifying the lattice, with the goal of operation at the reduced emittance in the fall of 1997. We also have conceived of a conversion of the TRISTAN Accumulation Ring to a dedicated light source of high energies. The on-going TRISTAN project will terminate by the end of 1995, and the TRISTAN Main Ring will be converted to a new B-Factory. At this moment, the TRISTAN Accumulation Ring will be disused as the injector to the Main Ring, and conversion of the AR to a dedicated light source becomes possible. (J.P.N.)

  20. Photon Factory Activity Report, 1994

    International Nuclear Information System (INIS)

    Photon Factory Activity Report no.12 deals with our activities in the period from October 1993 through September 1994. We operate two light sources at the Photon Factory; the 2.5-GeV Photon Factory storage ring, which is a dedicated light source, and the 6.5-GeV TRISTAN Accumulation Ring, which is parasitically used as a light source. We keep more than seventy experimental stations at two facilities, and accept experiments primarily according to approval by the Program Advisory Committee. The number of proposals to the Photon Factory has been still growing. Three-hundred eighty two proposals were approved by the PAC in FY1994, which is an increase by thirteen percent compared to the previous year. Remarkable was growth in biology proposals, particularly proposals in protein crystallography. In FY 1994, we accepted approximately 20,000 man-days as general users, and almost ten percent of them were from abroad. We always open the facility to users, not only domestic but also international. Recently we have been concentrating our effort to upgrading of the light sources and reconstruction of the experimental stations to keep the Photon Factory an attractive research facility in the forthcoming years. We have already started a program of reducing the emittance of the 2.5-GeV storage ring, which now operates with an emittance of 110 nm-rad, to 27 nm-rad by modifying the lattice, with the goal of operation at the reduced emittance in the fall of 1997. We also have conceived of a conversion of the TRISTAN Accumulation Ring to a dedicated light source of high energies. The on-going TRISTAN project will terminate by the end of 1995, and the TRISTAN Main Ring will be converted to a new B-Factory. At this moment, the TRISTAN Accumulation Ring will be disused as the injector to the Main Ring, and conversion of the AR to a dedicated light source becomes possible. (J.P.N.)

  1. Photon activation analysis of trace elements in several kinds of invertebrate animals. 1. Arthropoda crustacea

    International Nuclear Information System (INIS)

    Quantitative analysis of trace elements was made for marine mollusca by light quantum activation method. Crustacea which is likely to be well reflecting the environment of ocean floor was used as the subjects. Various kinds of these animals including Carcinus Portunus. Palinurus, Panulirus, Squilla etc. were collected from the sea off Japan to determine the concentrations of 15 kinds of elements in the gills, muscles, head/thorax region and viceraneous organs. The concentration of As was found markedly high in either of gills, muscles or viceraneous organs of Palinurus taken from the sea near Okinawa. It was found that there are no difference in the concentrations of As, Fe, Mn and Pb among the species studied and Fe, Mn and Pb were detected at high levels in the gills of Carcinus, whereas the Fe and Mn concentrations in the gills of Palinurus were considerably lower than other species tested. Thus, the element concentration was different among the regions studied and also species. (M.N.)

  2. Determination of fluorine in environmental and biological samples by neutron and photon activation analysis

    International Nuclear Information System (INIS)

    In NAA, two analytical reactions, viz. 19F(n,γ)20F (T(1/2) =11.0 s, E(gamma) =1633.6 keV) and 19F(n,p)19O (T(1/2) =26.9 s, E(gamma) =197.1 keV) with thermal and fast neutrons, respectively, can be used. Due to the short half-lives of the activation products, only non-destructive, instrumental NAA (INAA) is feasible. Unfortunately, neither of the analytical reactions is interference-free: the reaction 23Na(n,α)20F with fast neutrons interferes with the former, the reaction 18O(n,γ)19O with thermal neutrons interferes with the latter. The interference free detection limits for irradiation of several types of biological materials at thermal and fast neutron fluency rates of 8.1013 cm-2 s-1 and 2.1013 cm-2 s -1, respectively, are in the range of 0.3 to 2 μg g-1 for both reactions. The actual detection limits for biological samples, however, are significantly higher, at least by one order of magnitude, due to the above interferences. In addition, the detection limit of the 19F(n,γ)20F reaction is strongly influenced by the Al content, particularly in environmental samples, due to the overwhelming activity of 28Al created even after a very short irradiation (10 s). Thus, fluorine can usually be determined in this type of samples at levels of several hundreds to thousands of μg g-1. The pseudocyclic mode of INAA improves the detection limit only slightly - by a factor of 2 after four cycles, by a factor of 3.2 after ten cycles, etc. The determination of fluorine by PAA is based on the reaction 19F(γ,n)18F (T(1/2) = 1.83 h, E(gamma) = 511.0 keV) that is free from nuclear interferences for irradiation with up to 20-MeV bremsstrahlung. In contrast to NAA, radiochemical separation is mandatory for low-level assay of fluorine by PAA because the radionuclide 18F is a pure positron emitter. Therefore, a radiochemical PAA procedure (RPAA) was developed and tested for analysis of biological materials. It is based on alkaline-oxidative fusion with Na2O2 + NaOH followed by

  3. Photon Factory activity report, 1988

    International Nuclear Information System (INIS)

    Since the foundation of Photon Factory a decade age, it has played an important role as a unique synchrotron X-ray radiation source in Japan. Installation of various insertion devices, storage of intense positron beam and reduction of beam emittance were the substantial achievements in the last several years. The exploitation of the TRISTAN Accumulation Ring as a synchrotron radiation source has paved the way for a new potential of development. All these activities have brought about the increase of beamlines and the expansion of scientific fronts. Third International Conference on Synchrotron Radiation Instrumentation held in Tsukuba was one of the most highlighted events for the facility. In coming years, it is intended to open new research fields using the promising single bunch beam and circularly polarized wiggler radiation. The TRISTAN Main Ring also will be applied to synchrotron radiation research. The Photon Factory in a national synchrotron radiation research facility affiliated to the National Laboratory for High Energy Physics, and it consists of a 2.5 GeV electron linac, a 2.5 GeV storage ring as a synchrotron light source, beam lines and experimental stations. The operation, improvement and development in respective departments are reported. (Kako, I.)

  4. Nondestructive assay of fluorine in geological and other materials by instrumental photon activation analysis with a microtron

    Energy Technology Data Exchange (ETDEWEB)

    Krausová, Ivana [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Řež 130, 25068 Řež (Czech Republic); Mizera, Jiří, E-mail: mizera@ujf.cas.cz [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Řež 130, 25068 Řež (Czech Republic); Institute of Rock Structure and Mechanics, Academy of Sciences of the Czech Republic, V Holešovičkách 41, 182 09 Praha 8 (Czech Republic); Řanda, Zdeněk; Chvátil, David; Krist, Pavel [Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Řež 130, 25068 Řež (Czech Republic)

    2015-01-01

    Reliable determination of low concentrations of fluorine in geological and coal samples is difficult. It usually requires tedious decomposition and dissolution of the sample followed by chemical conversion of fluorine into its anionic form. The present paper examines possibilities of non-destructive determination of fluorine, mainly in minerals, rocks and coal, by instrumental photon activation analysis (IPAA) using the MT-25 microtron. The fluorine assay consists of counting the positron–electron annihilation line of {sup 18}F at 511 keV, which is a product of the photonuclear reaction {sup 19}F(γ, n){sup 18}F and a pure positron emitter. The assay is complicated by the simultaneous formation of other positron emitters. The main contributors to interference in geological samples are from {sup 45}Ti and {sup 34m}Cl, whereas those from {sup 44}Sc and {sup 89}Zr are minor. Optimizing beam energy and irradiation-decay-counting times, together with using interfering element calibration standards, allowed reliable IPAA determination of fluorine in selected USGS and CRPG geochemical reference materials, NIST coal reference materials, and NIST RM 8414 Bovine Muscle. In agreement with the published data obtained by PIGE, the results of the F assay by IPAA have revealed erroneous reference values provided for the NIST reference materials SRM 1632 Bituminous Coal and RM 8414 Bovine Muscle. The detection limits in rock and coal samples are in the range of 10–100 μg g{sup −1}.

  5. Nondestructive assay of fluorine in geological and other materials by instrumental photon activation analysis with a microtron

    International Nuclear Information System (INIS)

    Reliable determination of low concentrations of fluorine in geological and coal samples is difficult. It usually requires tedious decomposition and dissolution of the sample followed by chemical conversion of fluorine into its anionic form. The present paper examines possibilities of non-destructive determination of fluorine, mainly in minerals, rocks and coal, by instrumental photon activation analysis (IPAA) using the MT-25 microtron. The fluorine assay consists of counting the positron–electron annihilation line of 18F at 511 keV, which is a product of the photonuclear reaction 19F(γ, n)18F and a pure positron emitter. The assay is complicated by the simultaneous formation of other positron emitters. The main contributors to interference in geological samples are from 45Ti and 34mCl, whereas those from 44Sc and 89Zr are minor. Optimizing beam energy and irradiation-decay-counting times, together with using interfering element calibration standards, allowed reliable IPAA determination of fluorine in selected USGS and CRPG geochemical reference materials, NIST coal reference materials, and NIST RM 8414 Bovine Muscle. In agreement with the published data obtained by PIGE, the results of the F assay by IPAA have revealed erroneous reference values provided for the NIST reference materials SRM 1632 Bituminous Coal and RM 8414 Bovine Muscle. The detection limits in rock and coal samples are in the range of 10–100 μg g−1

  6. Photon Factory activity report, 1989

    International Nuclear Information System (INIS)

    At the Photon Factory about 500 experiments are now running annually with about 50 experimental stations, the total operation time of the 2.5 GeV storage ring was 3400 hour in 1989, and the number of users was more than 2000, including 300 scientists from industry. This wide usage of synchrotron radiation has been supported by good performance of the accelerators. The positron beam current of the linac was increased for rapid injection (injection time: 20 min). The entire roof of the Light Source building was covered with thermal insulator (urethane-foam). This has greatly improved the beam stability of the ring. It has been operated at an initial ring current of 350 mA with a life time of 20 hours. Distinctive instrumentation at the Photon Factory has expanded to various fields such as angle-resolved ion-spectroscopy, dispersive EXAFS, trace impurity X-ray fluorescence analysis, plane-wave topography, structure analysis under high pressure, and imaging plates. Recently, experiments of protein structure analysis have been carried out extensively; Sakabe developed a new type of Weissenberg camera for protein crystallography, and about 50 experiments have been done for the past six months by a combination of Sakabe camera and imaging plates. The 2.5 GeV light source is now at an entrance of its harvest season. The TRISTAN Accumulation Ring has been used throughout this year in a time sharing basis with the TRISTAN experiment; twenty minutes for injection to TRISTAN Main Ring and 2 hours for SR experiment. The main subject has been magnetic Compton scattering with circularly polarized wiggler radiation. Such experiences enable us to expand our perspective for research in the following decade; we are investigating the possibility of operating the TRISTAN Main Ring at 6-8 GeV with 6000-pole undulaters, resulting in an extremely brilliant radiation source (Emittance: 0.1 nm·rad at 5 GeV with damping rings). (J.P.N.)

  7. Nonlinear Gain Saturation in Active Slow Light Photonic Crystal Waveguides

    DEFF Research Database (Denmark)

    Chen, Yaohui; Mørk, Jesper

    2013-01-01

    We present a quantitative three-dimensional analysis of slow-light enhanced traveling wave amplification in an active semiconductor photonic crystal waveguides. The impact of slow-light propagation on the nonlinear gain saturation of the device is investigated.......We present a quantitative three-dimensional analysis of slow-light enhanced traveling wave amplification in an active semiconductor photonic crystal waveguides. The impact of slow-light propagation on the nonlinear gain saturation of the device is investigated....

  8. Simulation of Nonlinear Gain Saturation in Active Photonic Crystal Waveguides

    DEFF Research Database (Denmark)

    Chen, Yaohui; Mørk, Jesper

    2012-01-01

    In this paper we present a theoretical analysis of slowlight enhanced traveling wave amplification in an active semiconductor Photonic crystal waveguides. The impact of group index on nonlinear modal gain saturation is investigated.......In this paper we present a theoretical analysis of slowlight enhanced traveling wave amplification in an active semiconductor Photonic crystal waveguides. The impact of group index on nonlinear modal gain saturation is investigated....

  9. Photon factory activity report, 1993

    International Nuclear Information System (INIS)

    This issue is the annual report of the Photon Factory, National Laboratory of High Energy Physics. First the outline of the Photon Factory is presented. Injector linac, light source, beamlines and instrumentation, synchrotron radiation facility at the Tristan accumulation ring, and the Tristan super light facility are described in detail. The facility is open to researchers. The user's reports are collected as well. (J.P.N.)

  10. Photon factory activity report, 1992

    International Nuclear Information System (INIS)

    This issue is the annual report of the Photon Factory, National laboratory of High Energy Physics. First, the outline of the Photon Factory is presented. Injector linac, light source, beamlines and instrumentation, the Tristan synchrotron radiation facility at the accumulation ring, and the Tristan super light facility are described in detail. The facility is open to researchers. The user's reports are collected as well. (J.P.N.) (435 refs.)

  11. Application of epithermal neutron activation in multielement analysis of silicate rocks employing both coaxial Ge(Li) and low energy photon detector systems

    Science.gov (United States)

    Baedecker, P.A.; Rowe, J.J.; Steinnes, E.

    1977-01-01

    The instrumental activation analysis of silicate rocks using epithermal neutrons has been studied using both high resolution coaxial Ge(Li) detectors and low energy photon detectors, and applied to the determination of 23 elements in eight new U.S.G.S. standard rocks. The analytical use X-ray peaks associated with electron capture or internal conversion processes has been evaluated. Of 28 elements which can be considered to be determinable by instrumental means, the epithermal activation approach is capable of giving improved sensitivity and precision in 16 cases, over the normal INAA procedure. In eleven cases the use of the low energy photon detector is thought to show advantages over convertional coaxial Ge(Li) spectroscopy. ?? 1977 Akade??miai Kiado??.

  12. Photon Factory activity report, 1991

    International Nuclear Information System (INIS)

    The Photon Factory is a national synchrotron radiation research facility affiliated with the National Laboratory for High Energy Physics located in Tsukuba Science City. The Photon Factory consists of a 2.5 GeV electron/positron linear accelerator, a 2.5 GeV electron/positron storage ring, beam lines and experimental stations. All the facilities for synchrotron radiation research are open to scientists. A part of the accumulation ring of the TRISTAN main ring has been used as a synchrotron radiation source in the energy range from 5.8 to 6.5 GeV. The Photon Factory is composed of three divisions of Injector Linac, Light Source and Instrumentation. The researches of each divisions are reviewed, and the users' short reports are collected. The list of published papers with author index is also included in the publication. (K.I.) 233 refs

  13. Photon Factory activity report, 1995

    International Nuclear Information System (INIS)

    The Photon Factory at the National Laboratory for High Energy Physics is a national facility for scientific research utilizing synchrotron radiation. Although the Photon Factory operator the linear injector, two light sources including the 2.5 GeV storage ring and the 6.5 GeV TRISTAN accumulation Ring as well as a major fraction of their beamlines and experimental station. This report is covered the period from October 1994 to September 1995. The total number of proposals by this PAC was 399 in 1995. Facility development projects currently in progress include the following, TRISTAN Super Light Facility (TSLF) project, VUV-FEL project, KEKB project and Slow-positron Source. This report contents outline of the Photon Factory, introduction, scientific disciplines, electronic properties of condensed matters, atomic and molecular science, X-ray imaging, radiobiology using synchrotron radiation, structural properties of condensed matters, structural properties of solid surfaces and adsorbates, structure and function of proteins, theoretical researches, experimental facilities, beamlines, new instrumentation, AR Upgrade, collaborations, projects, user's short reports, list of published papers 1994/95. (S.Y.)

  14. Photon Factory activity report, 1995

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-12-31

    The Photon Factory at the National Laboratory for High Energy Physics is a national facility for scientific research utilizing synchrotron radiation. Although the Photon Factory operator the linear injector, two light sources including the 2.5 GeV storage ring and the 6.5 GeV TRISTAN accumulation Ring as well as a major fraction of their beamlines and experimental station. This report is covered the period from October 1994 to September 1995. The total number of proposals by this PAC was 399 in 1995. Facility development projects currently in progress include the following, TRISTAN Super Light Facility (TSLF) project, VUV-FEL project, KEKB project and Slow-positron Source. This report contents outline of the Photon Factory, introduction, scientific disciplines, electronic properties of condensed matters, atomic and molecular science, X-ray imaging, radiobiology using synchrotron radiation, structural properties of condensed matters, structural properties of solid surfaces and adsorbates, structure and function of proteins, theoretical researches, experimental facilities, beamlines, new instrumentation, AR Upgrade, collaborations, projects, user`s short reports, list of published papers 1994/95. (S.Y.)

  15. Photon Factory activity report, 1987

    International Nuclear Information System (INIS)

    The Photon Factory made great strides in 1987. The low emittance operation of the PF ring was achieved in March, and resulted favorably in the increase of brilliance from 2 to 20 times for all the beam lines with high beam stability. At the same time, the installation of inserted devices was under way for all available straight sections of the ring. A 54-pole wiggler-undulator has been commissioned at BL-16. The devices to be inserted in the near future are a multipole wiggler for BL-13, an undulator for BL-19, and an undulator for circular polarized radiation at BL-28. The construction of beam lines continued, and four new beam lines, BL-6, BL-9, BL-16 and BL-17, are now in operation, BL-13 and BL-19 are under construction, and BL-3, BL-5, BL-18, BL-20 and BL-28 are in the design stage. Since its inauguration with four beam lines in 1982, the Photon Factory has grown rapidly, and approaches the goal of operating the PF ring with positrons in full use of its 24 beam ports and the straight sections for inserted devices. The total operation time was limited to 3,000 hours by the budget for fiscal year 1987, and about 80 % of the operation hours were devoted to the experiments of users. The nearly perfect operation of the 400 m long linac has continued in 1987, and has supplied both electrons and positrons to the TRISTAN collision experiment. The light source of a 2.5 GeV electron storage ring was normally operated. (Kako, I.)

  16. Photonic Crystals Mathematical Analysis and Numerical Approximation

    CERN Document Server

    Dörfler, Willy; Plum, Michael; Schneider, Guido; Wieners, Christian

    2011-01-01

    This book concentrates on the mathematics of photonic crystals, which form an important class of physical structures investigated in nanotechnology. Photonic crystals are materials which are composed of two or more different dielectrics or metals, and which exhibit a spatially periodic structure, typically at the length scale of hundred nanometers. In the mathematical analysis and the numerical simulation of the partial differential equations describing nanostructures, several mathematical difficulties arise, e. g., the appropriate treatment of nonlinearities, simultaneous occurrence of contin

  17. Active glass for photonic devices photoinduced structures and their application

    CERN Document Server

    Mitsuyu, Tsuneo; Si, Jinhai; Qiu, Jianrong

    2001-01-01

    This book focuses on selected topics which are new and of fundamental importance in the application of active glasses in photonic devices Most of the chapters deal with glasses under the action of higher electromagnetic fields, such as those produced by femtosecond lasers They cover the creation and analysis of induced structures in glasses and some functional devices using active glasses This book is designed for both graduate students and researchers in the field

  18. Active neutron/photon personal dosemeters

    International Nuclear Information System (INIS)

    Though active personal dosemeters for photon fields reflect already a high level of development, there is still a need to advance the design of dosemeters for use in mixed neutron/photon fields and especially for monitoring the staff of nuclear power plants and the personnel accompanying transports of spent fuel flasks. The measurement of the neutron component is usually associated with problems. After a short description of the complex mixed fields in the nuclear fuel cycle, the commercially available active dosemeters and those under development will be listed and problems arising from their use in these fields will be discussed. Two new developments, the Siemens EPD-N2 and the PTB DOS-2002, which both are capable of indicating neutron and photon doses, will be described and discussed in detail. New response functions with respect to personal dose equivalent Hp(10) will be presented for neutrons. They have been determined by measurements in the quasi-monoenergetic reference fields at PTB in the energy range from 24 keV to 14.8 MeV and in fields with broad spectral distributions using the radionuclide sources 252Cf(bare), 252Cf(D2O,mod) - with and without cadmium shielding - 241Am-Be as well as a thermal neutron beam. The spectral distributions of all fields and the readings of the dosemeters in these fields were taken as inputs for an unfolding procedure to determine the dosemeter response in the overall energy region from thermal to 15 MeV. The procedure was tested by folding the dosemeter response with the broad neutron spectra and comparing with the readings of the dosemeters. Another problem in practical workplace fields is linked with high energy photons. Photons with energies from 6 MeV to 7 MeV from the 16O(n,pγ) reaction contribute to dose, particularly at reactors, and have to be taken into account when dosemeters are processed. Measurements with high energy photons were therefore performed with both devices and will be discussed. Finally, practical

  19. The Gain Properties of 1-D Active Photonic Crystal

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The terminology 'ID frequency'(w ID) is proposed after analyzing the 1D active photonic crystal based on the transfer matrix method. The relationship between wID and the structure parameters of the photonic crystal is investigated.

  20. Photon factory accelerator status and activities

    International Nuclear Information System (INIS)

    The present report addresses the Photon Factory, a user-based facility for synchrotron-radiation research at the National Laboratory for High Energy Physics (KEK) in Japan. It consists of a 2.5 GeV storage ring and an electron-positron linac. Its construction started in 1978 and the accelerators were commissioned in 1982. The Photon Factory storage ring is a dedicated synchrotron-radiation source with a critical photon energy of 4 keV. There are 23 spaces in which front-ends (beamlines) can be installed for introducing synchrotron radiation into the experimental hall. Twenty front-ends are available for user experiments. The report particularly describes the status of the linac and the storage ring, focusing on major features of the linac operation and storage ring operation. The recent improvements are then outlined, focusing on positron beam injection and operation, improvement of the high-power pulsed klystron, monitor and control system, daily drift of the light axis, and operation of the new superconducting vertical wiggler. The accelerator activities are then described, centering on the test linac and a plan to use the TRISTAN MR as a synchrotron radiation source. (N.K.)

  1. Modelling of Active Semiconductor Photonic Crystal Waveguides and Robust Designs based on Topology Optimization

    DEFF Research Database (Denmark)

    Chen, Yaohui; Wang, Fengwen; Ek, Sara; Jensen, Jakob Søndergaard; Sigmund, Ole; Mørk, Jesper

    2011-01-01

    In this paper, we present a theoretical analysis of slow-light enhanced light amplification in an active semiconductor photonic crystal line defect waveguide. The impact of enhanced light-matter interactions on propagation effects and local carrier dynamics are investigated in the framework of the...... Lorentz reciprocity theorem. We highlight topology optimization as a systematic and robust design methodology considering manufacturing imperfections in optimizing active photonic crystal device performances, and compare the performance of standard photonic crystal waveguides with optimized structures....

  2. Advanced active quenching circuits for single-photon avalanche photodiodes

    Science.gov (United States)

    Stipčević, M.; Christensen, B. G.; Kwiat, P. G.; Gauthier, D. J.

    2016-05-01

    Commercial photon-counting modules, often based on actively quenched solid-state avalanche photodiode sensors, are used in wide variety of applications. Manufacturers characterize their detectors by specifying a small set of parameters, such as detection efficiency, dead time, dark counts rate, afterpulsing probability and single photon arrival time resolution (jitter), however they usually do not specify the conditions under which these parameters are constant or present a sufficient description. In this work, we present an in-depth analysis of the active quenching process and identify intrinsic limitations and engineering challenges. Based on that, we investigate the range of validity of the typical parameters used by two commercial detectors. We identify an additional set of imperfections that must be specified in order to sufficiently characterize the behavior of single-photon counting detectors in realistic applications. The additional imperfections include rate-dependence of the dead time, jitter, detection delay shift, and "twilighting." Also, the temporal distribution of afterpulsing and various artifacts of the electronics are important. We find that these additional non-ideal behaviors can lead to unexpected effects or strong deterioration of the system's performance. Specifically, we discuss implications of these new findings in a few applications in which single-photon detectors play a major role: the security of a quantum cryptographic protocol, the quality of single-photon-based random number generators and a few other applications. Finally, we describe an example of an optimized avalanche quenching circuit for a high-rate quantum key distribution system based on time-bin entangled photons.

  3. Workshop on photon activation therapy: proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Fairchild, R.G. (ed.)

    1985-04-18

    This Workshop was held concurrently with an IAEA Research Coordination Meeting on Exploration of the Possibility of High-LET Radiation for Non-conventional Radiotherapy in Cancer. The Workshop on Photon Activation Therapy (PAT) was given as a special session on April 18, as it was thoght PAT might eventually be found to be attractive to developing countries, which is a major concern of the IAEA. An effort was made to bring together representatives of the various groups known to be actively working on PAT; these included investigators from Sweden and Japan as well as the US. It is hoped that this compendium of papers will be of use to those currently active in this developing field, as well as to those who might join this area of endeavor in the future.

  4. Study on photon activation analysis of carbon in glasses for fiber amplifiers by using the flow method for the rapid separation of 11C

    International Nuclear Information System (INIS)

    We have studied nuclear interference from a matrix produced by (γ, n), (γ, 2n), (γ, p) and (n, γ) reactions and a flow method for 11C separation in order to develop an approach for the photon activation analysis of carbon in InF3-based fluoride, chalcogenide and tellurite glasses for fiber amplifiers. We found that seventeen radionuclides are produced from these glasses and chemical separation is necessary to determine carbon. For the flow method, which involves the fusion of an irradiated sample with an oxidizer, the conversion of 11C into 11CO2 and the absorption of 11C in ethanolamine solution, we used a mixture of Pb3O4 and B2O3 as the oxidizer. We also found that the reaction between 19F(γ, n) and 23Na(γ, αn) in the ethanolamine solution produced 18F contamination with fluoride and chalcogenide glasses and that this flow method can only be applied to tellurite glasses. We confirmed that the chemical yield of the flow method was close to 100% when determining carbon in standard steel samples by using lithium carbonate as a standard sample. We determined that the carbon concentrations in two kinds of tellurite glass were 8 to 13 and 21 to 28 ppm, respectively. (author)

  5. Neutron- and photon-activation detection limits in breast milk analysis for prospective dose evaluation of the suckling infant

    International Nuclear Information System (INIS)

    Complex situations related to the environment, as in the regions affected by the Chernobyl accident and regions in which nuclear weapons testing were undertaken, as in Semipalatinsk, could be reflected in the trace element content in mothers' milk. The evaluation of fractional transfer to milk of ingested or inhaled activity and of the corresponding dose coefficients for the infant, following a mothers' radioactive intake, can take advantage from wide-ranging studies of elemental and radionuclide contents in mothers' milk. In this work the possibility to determine elements, such as Ru, Zr, Nb, Te, Ce, Th, U, in milk powder has been investigated. Although results from elemental analyses of breast milk are to be found in the literature, the determination of the identified elements has attracted poor attention since they are not considered essential elements from a biological point of view. Nevertheless, in the case of radioactive releases to the environment, such data could be of interest in evaluation of dose to the breast-fed infant

  6. Activation analysis

    International Nuclear Information System (INIS)

    The neutron activation analysis, which appears to be in limits for further advance, is the most suitable for providing information on the principal as well as the microcomponents in any sample of solid form. Then, instrumental activation analysis is capable of determination of far many elements in various samples. Principally on the neutron activation analysis, the following are described in literature survey from 1982 to middle 1984: bibliography, review, data collection, etc.; problems in spectral analysis and measurement; activation analysis with neutrons; charged particle and photo-nucleus reactions; chemical separation, isotopic dilution activation analysis; molecular activation analysis; standard materials; life and its relation samples; environmental, food, court trial and archaeological samples; space and earth sciences. (Mori, K.)

  7. Materials analysis using photon-in photon-out spectroscopy

    International Nuclear Information System (INIS)

    Recent interest in nanotechnology and Organic Light Emitting Devices (OLED) has prompted intense research in the electronic structure and optical properties of relevant materials. Here we report recent development and applications of X-ray excited optical luminescence (XEOL). XEOL, using tunable synchrotron light as an excitation source, monitors the optical response following inner shell excitation of an element in a light emitting material in both the energy and time domain. XEOL from several prototype materials will be presented to illustrate its application in material analysis. In XEOL measurements, we first record the x-ray absorption near edge structures (XANES) of an element, e.g. carbon K-edge in OLED materials and Si K-edge in silicon nanostructures. Photon energies from below to above the edge are then selected to excite the system. Photoluminescence is recorded with conventional optical monochromator and photomultiplier (PMT) instrumentation. The total luminescence yield (zero order) or the partial luminescence yield (PLY), is in turn used to obtain the XANES. In time-resolved studies, the short synchrotron light pulse is used as a strobe. Here, the PMT signal (∼2 ns resolution) is used as the start and the synchrotron pulse (bunch clock) as the stop. The time interval between the strobes is used to monitor the intensity decay. A time window (e.g. 0-10 ns after excitation) can be selected between pulses. The light emitted within this window is used to record time-resolved XEOL (TRXEOL) and optical XANES. Timing measurements reported here were conducted at the Advanced Photon Source (APS) in a top-up mode, and the Synchrotron Radiation Center (SRC), University of Wisconsin-Madison and the Canadian Light Source (CLS) using a single bunch. The pulse width was <100 ps in all cases and the repetition rate at APS, SRC and CLS was 153 ns, 300 ns, and 570 ns, respectively. A schematic is shown in Fig.1 where the green arrow represents the SR pulse and the red

  8. Experimental generation of single photons via active multiplexing

    International Nuclear Information System (INIS)

    An on-demand single-photon source is a fundamental building block in quantum science and technology. We experimentally demonstrate the proof of concept for a scheme to generate on-demand single photons via actively multiplexing several heralded photons probabilistically produced from pulsed spontaneous parametric down-conversions (SPDCs). By utilizing a four-photon-pair source, an active feed-forward technique, and an ultrafast single-photon router, we show a fourfold enhancement of the output photon rate. Simultaneously, we maintain the quality of the output single-photon states, confirmed by correlation measurements. We also experimentally verify, via Hong-Ou-Mandel interference, that the router does not affect the indistinguishability of the single photons. Furthermore, we give numerical simulations, which indicate that photons based on multiplexing of four SPDC sources can outperform the heralding based on highly advanced photon-number-resolving detectors. Our results show a route for on-demand single-photon generation and the practical realization of scalable linear optical quantum-information processing.

  9. Actively doped solid core Photonic Bandgap Fiber

    DEFF Research Database (Denmark)

    Broeng, Jes; Olausson, Christina Bjarnal Thulin; Lyngsøe, Jens Kristian;

    2010-01-01

    Solid photonic bandgap fibers offer distributed spectral filtering with extraordinary high suppression. This opens new possibilities of artificially tailoring the gain spectrum of fibers. We present record-performance of such fibers and outline their future applications....

  10. Monolithically Integrated Ge-on-Si Active Photonics

    Directory of Open Access Journals (Sweden)

    Jifeng Liu

    2014-07-01

    Full Text Available Monolithically integrated, active photonic devices on Si are key components in Si-based large-scale electronic-photonic integration for future generations of high-performance, low-power computation and communication systems. Ge has become an interesting candidate for active photonic devices in Si photonics due to its pseudo-direct gap behavior and compatibility with Si complementary metal oxide semiconductor (CMOS processing. In this paper, we present a review of the recent progress in Ge-on-Si active photonics materials and devices for photon detection, modulation, and generation. We first discuss the band engineering of Ge using tensile strain, n-type doping, Sn alloying, and separate confinement of Γ vs. L electrons in quantum well (QW structures to transform the material towards a direct band gap semiconductor for enhancing optoelectronic properties. We then give a brief overview of epitaxial Ge-on-Si materials growth, followed by a summary of recent investigations towards low-temperature, direct growth of high crystallinity Ge and GeSn alloys on dielectric layers for 3D photonic integration. Finally, we review the most recent studies on waveguide-integrated Ge-on-Si photodetectors (PDs, electroabsorption modulators (EAMs, and laser diodes (LDs, and suggest possible future research directions for large-scale monolithic electronic-photonic integrated circuits on a Si platform.

  11. Instrumental neutron and photon activation analyses of selected geochemical reference materials

    Czech Academy of Sciences Publication Activity Database

    Mizera, Jiří; Řanda, Zdeněk

    2010-01-01

    Roč. 284, č. 1 (2010), s. 157-163. ISSN 0236-5731 R&D Projects: GA AV ČR IAA300130706 Institutional research plan: CEZ:AV0Z10480505 Keywords : neutron activation analysis * photon activation analysis * geochemical reference materials Subject RIV: BG - Nuclear, Atomic and Molecular Physics, Colliders Impact factor: 0.777, year: 2010

  12. Analysis of lateritic material from Cerro Impacto by instrumental neutron activation employing a low-energy photon semiconductor and a high-energy Ge(Li) detector

    International Nuclear Information System (INIS)

    Nineteen elements were determined in four different grain size fractions of a bulk geological material from Cerro Impacto for a study of the physical (mechanical) concentration process of different elements based upon the hardness of the different minerals. The analysis was performed by excitation of the sample with a high, slow neutron flux followed by gamma-ray spectroscopy with both a conventional Ge(Li) high-energy detector and a low-energy photon detector (LEPD). The accuracy of this method was studied with the use of two standard reference materials, SY-2 and SY-3, which are similar to the real samples. The values determined were also compared with a secondary target x-ray fluorescence method for all the elements that were suitable to both methods. Actually, the x-ray fluorescence method was found to be more complementary than competitive. 10 refs., 2 figs., 4 tabs

  13. Active learning in optics and photonics: Fraunhofer diffraction

    Science.gov (United States)

    Ghalila, H.; Ben Lakhdar, Z.; Lahmar, S.; Dhouaidi, Z.; Majdi, Y.

    2014-07-01

    "Active Learning in Optics and Photonics" (ALOP), funded by UNESCO within its Physics Program framework with the support of ICTP (Abdus Salam International Centre for Theoretical Physics) and SPIE (Society of Photo-Optical Instrumentation Engineers), aimed to helps and promotes a friendly and interactive method in teaching optics using simple and inexpensive equipment. Many workshops were organized since 2005 the year when Z. BenLakhdar, whom is part of the creators of ALOP, proposed this project to STO (Société Tunisienne d'Optique). These workshops address several issues in optics, covering geometrical optics, wave optics, optical communication and they are dedicated to both teachers and students. We focus this lecture on Fraunhofer diffraction emphasizing the facility to achieve this mechanism in classroom, using small laser and operating a slit in a sheet of paper. We accompany this demonstration using mobile phone and numerical modeling to assist in the analysis of the diffraction pattern figure.

  14. Numerical analysis of multicore photonic crystal fibers

    Institute of Scientific and Technical Information of China (English)

    Yanfeng Li(栗岩锋); Qingyue Wang(王清月); Minglie Hu(胡明列)

    2003-01-01

    A Galerkin's method-based numerical procedure is extended to obtain the modal field distribution ofmulticore photonic crystal fibers for the first time to our knowledge, which can reveal how the air hole sizeinfluences the mode coupling and how the coupling strength varies with wavelength. These results will behelpful in the future design of multicore photonic crystal fibers with proper guidance properties.

  15. Q value analysis of microwave photonic filters

    Institute of Scientific and Technical Information of China (English)

    Lina ZHOU; Xinliang ZHANG; Enming XU

    2009-01-01

    This paper first presents the fundamental principles of the microwave photonic filters.As an example to explain how to implement a microwave photonic filter, a specific finite impulse response (FIR) filter is illustrated.Next, the Q value of the microwave photonic filters is analyzed theoretically, and methods around how to gain high Q value are discussed.Then,divided into FIR filter, first-order infinite impulse response (IIR) filter, and multi-order IIR filter, several novel microwave photonic filters with high Q value are listed and compared.The technical difficulties to get high Q value in first-order IIR filter and multi-order IIR filter are analyzed concretely.Finally, in order to gain higher Q value, a multi-order IIR microwave photonic filter that easily extends its order is presented and discussed.

  16. Full Quantum Analysis of Two-Photon Absorption Using Two-Photon Wavefunction: Comparison with One-Photon Absorption

    OpenAIRE

    Nakanishi, Toshihiro; Kobayashi, Hirokazu; Sugiyama, Kazuhiko; Kitano, Masao

    2009-01-01

    For dissipation-free photon-photon interaction at the single photon level, we analyze one-photon transition and two-photon transition induced by photon pairs in three-level atoms using two-photon wavefunctions. We show that the two-photon absorption can be substantially enhanced by adjusting the time correlation of photon pairs. We study two typical cases: Gaussian wavefunction and rectangular wavefunction. In the latter, we find that under special conditions one-photon transition is complete...

  17. Measuring ultrafast protein folding rates from photon-by-photon analysis of single molecule fluorescence trajectories

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Hoi Sung, E-mail: chunghoi@niddk.nih.gov [Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520 (United States); Cellmer, Troy; Louis, John M. [Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520 (United States); Eaton, William A., E-mail: eaton@helix.nih.gov [Laboratory of Chemical Physics, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, MD 20892-0520 (United States)

    2013-08-30

    Highlights: ► Photon trajectories were measured for an ultrafast folding protein using single molecule FRET. ► Folding rates were obtained from a photon-by-photon analysis using a maximum likelihood method. ► Incorporating acceptor blinking into the analysis improved the accuracy of the extracted rates. ► The rates agree with the results from both the correlation analysis and ensemble laser temperature-jump. - Abstract: Folding and unfolding rates for the ultrafast folding villin subdomain were determined from a photon-by-photon analysis of fluorescence trajectories in single molecule FRET experiments. One of the obstacles to measuring fast kinetics in single molecule fluorescence experiments is blinking of the fluorophores on a timescale that is not well separated from the process of interest. By incorporating acceptor blinking into a two-state kinetics model, we show that it is possible to extract accurate rate coefficients on the microsecond time scale for folding and unfolding using the maximum likelihood method of Gopich and Szabo. This method yields the most likely parameters of a given model that can reproduce the observed photon trajectories. The extracted parameters agree with both the decay rate of the donor–acceptor cross correlation function and the results of ensemble equilibrium and kinetic experiments using nanosecond laser temperature jump.

  18. Measuring ultrafast protein folding rates from photon-by-photon analysis of single molecule fluorescence trajectories

    International Nuclear Information System (INIS)

    Highlights: ► Photon trajectories were measured for an ultrafast folding protein using single molecule FRET. ► Folding rates were obtained from a photon-by-photon analysis using a maximum likelihood method. ► Incorporating acceptor blinking into the analysis improved the accuracy of the extracted rates. ► The rates agree with the results from both the correlation analysis and ensemble laser temperature-jump. - Abstract: Folding and unfolding rates for the ultrafast folding villin subdomain were determined from a photon-by-photon analysis of fluorescence trajectories in single molecule FRET experiments. One of the obstacles to measuring fast kinetics in single molecule fluorescence experiments is blinking of the fluorophores on a timescale that is not well separated from the process of interest. By incorporating acceptor blinking into a two-state kinetics model, we show that it is possible to extract accurate rate coefficients on the microsecond time scale for folding and unfolding using the maximum likelihood method of Gopich and Szabo. This method yields the most likely parameters of a given model that can reproduce the observed photon trajectories. The extracted parameters agree with both the decay rate of the donor–acceptor cross correlation function and the results of ensemble equilibrium and kinetic experiments using nanosecond laser temperature jump

  19. Modeling of gain saturation effects in active semiconductor photonic crystal waveguides

    DEFF Research Database (Denmark)

    Chen, Yaohui; Mørk, Jesper

    2012-01-01

    In this paper, we present a theoretical analysis of slow-light enhanced light amplification in an active semiconductor photonic crystal line defect waveguide. The impact of enhanced light-matter interactions on carrier-depletion-induced modal gain saturation is investigated.......In this paper, we present a theoretical analysis of slow-light enhanced light amplification in an active semiconductor photonic crystal line defect waveguide. The impact of enhanced light-matter interactions on carrier-depletion-induced modal gain saturation is investigated....

  20. Cascaded systems analysis of photon counting detectors

    Energy Technology Data Exchange (ETDEWEB)

    Xu, J.; Zbijewski, W.; Gang, G.; Stayman, J. W. [Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205 (United States); Taguchi, K.; Carrino, J. A. [Russell H. Morgan Department of Radiology, Johns Hopkins University, Baltimore, Maryland 21205 (United States); Lundqvist, M.; Fredenberg, E. [Philips Healthcare, Solna 171 41 (Sweden); Siewerdsen, J. H., E-mail: jeff.siewerdsen@jhu.edu [Department of Biomedical Engineering, Johns Hopkins University, Baltimore, Maryland 21205 (United States); Russell H. Morgan Department of Radiology, Johns Hopkins University, Baltimore, Maryland 21205 (United States)

    2014-10-15

    Purpose: Photon counting detectors (PCDs) are an emerging technology with applications in spectral and low-dose radiographic and tomographic imaging. This paper develops an analytical model of PCD imaging performance, including the system gain, modulation transfer function (MTF), noise-power spectrum (NPS), and detective quantum efficiency (DQE). Methods: A cascaded systems analysis model describing the propagation of quanta through the imaging chain was developed. The model was validated in comparison to the physical performance of a silicon-strip PCD implemented on an experimental imaging bench. The signal response, MTF, and NPS were measured and compared to theory as a function of exposure conditions (70 kVp, 1–7 mA), detector threshold, and readout mode (i.e., the option for coincidence detection). The model sheds new light on the dependence of spatial resolution, charge sharing, and additive noise effects on threshold selection and was used to investigate the factors governing PCD performance, including the fundamental advantages and limitations of PCDs in comparison to energy-integrating detectors (EIDs) in the linear regime for which pulse pileup can be ignored. Results: The detector exhibited highly linear mean signal response across the system operating range and agreed well with theoretical prediction, as did the system MTF and NPS. The DQE analyzed as a function of kilovolt (peak), exposure, detector threshold, and readout mode revealed important considerations for system optimization. The model also demonstrated the important implications of false counts from both additive electronic noise and charge sharing and highlighted the system design and operational parameters that most affect detector performance in the presence of such factors: for example, increasing the detector threshold from 0 to 100 (arbitrary units of pulse height threshold roughly equivalent to 0.5 and 6 keV energy threshold, respectively), increased the f{sub 50} (spatial

  1. Photonics

    CERN Document Server

    Andrews, David L

    2015-01-01

    Discusses the basic physical principles underlying Biomedical Photonics, spectroscopy and microscopy This volume discusses biomedical photonics, spectroscopy and microscopy, the basic physical principles underlying the technology and its applications. The topics discussed in this volume are: Biophotonics; Fluorescence and Phosphorescence; Medical Photonics; Microscopy; Nonlinear Optics; Ophthalmic Technology; Optical Tomography; Optofluidics; Photodynamic Therapy; Image Processing; Imaging Systems; Sensors; Single Molecule Detection; Futurology in Photonics. Comprehensive and accessible cov

  2. Photonics

    CERN Document Server

    Andrews, David L

    2015-01-01

    This book covers modern photonics accessibly and discusses the basic physical principles underlying all the applications and technology of photonicsThis volume covers the basic physical principles underlying the technology and all applications of photonics from statistical optics to quantum optics. The topics discussed in this volume are: Photons in perspective; Coherence and Statistical Optics; Complex Light and Singular Optics; Electrodynamics of Dielectric Media; Fast and slow Light; Holography; Multiphoton Processes; Optical Angular Momentum; Optical Forces, Trapping and Manipulation; Pol

  3. Photonics

    CERN Document Server

    Andrews, David L

    2015-01-01

    Discusses the basic physical principles underlying the technology instrumentation of photonics This volume discusses photonics technology and instrumentation. The topics discussed in this volume are: Communication Networks; Data Buffers; Defense and Security Applications; Detectors; Fiber Optics and Amplifiers; Green Photonics; Instrumentation and Metrology; Interferometers; Light-Harvesting Materials; Logic Devices; Optical Communications; Remote Sensing; Solar Energy; Solid-State Lighting; Wavelength Conversion Comprehensive and accessible coverage of the whole of modern photonics Emphas

  4. Photonics

    CERN Document Server

    Andrews, David L

    2015-01-01

    Discusses the basic physical principles underlying thescience and technology of nanophotonics, its materials andstructures This volume presents nanophotonic structures and Materials.Nanophotonics is photonic science and technology that utilizeslight/matter interactions on the nanoscale where researchers arediscovering new phenomena and developing techniques that go wellbeyond what is possible with conventional photonics andelectronics.The topics discussed in this volume are: CavityPhotonics; Cold Atoms and Bose-Einstein Condensates; Displays;E-paper; Graphene; Integrated Photonics; Liquid Cry

  5. Polarization rotator-splitters in standard active silicon photonics platforms.

    Science.gov (United States)

    Sacher, Wesley D; Barwicz, Tymon; Taylor, Benjamin J F; Poon, Joyce K S

    2014-02-24

    We demonstrate various silicon-on-insulator polarization management structures based on a polarization rotator-splitter that uses a bi-level taper TM0-TE1 mode converter. The designs are fully compatible with standard active silicon photonics platforms with no new levels required and were implemented in the IME baseline and IME-OpSIS silicon photonics processes. We demonstrate a polarization rotator-splitter with polarization crosstalk polarization rotator-splitter with directional coupler polarization filters. Finally, we demonstrate a polarization controller by integrating the polarization rotator-splitters with directional couplers, thermal tuners, and PIN diode phase shifters. PMID:24663698

  6. Fabrication and Analysis of Photonic Crystals

    Science.gov (United States)

    Campbell, Dean J.; Korte, Kylee E.; Xia, Younan

    2007-01-01

    These laboratory experiments are designed to explore aspects of nanoscale chemistry by constructing and spectroscopically analyzing thin films of photonic crystals. Films comprised of colloidal spheres and polydimethylsiloxane exhibit diffraction-based stop bands that shift reversibly upon exposure to some common solvents. Topics covered in these…

  7. Finite element analysis of photonic crystal fibers

    NARCIS (Netherlands)

    Uranus, H.P.; Hoekstra, H.J.W.M.; Groesen, van E.

    2005-01-01

    A finite-element-based vectorial optical mode solver, furnished with Bayliss-Gunzburger-Turkel-like transparent boundary conditions, is used to rigorously analyze photonic crystal fibers (PCFs). Both the real and imaginary part of the modal indices can be computed in a relatively small computational

  8. Vectorial analysis of dielectric photonic crystal VCSEL

    DEFF Research Database (Denmark)

    Chung, Il-Sug; Mørk, Jesper

    A new vertical-cavity surface-emitting laser structure employing a dielectric photonic crystal mirror has been suggested and been numerically investigated. The new structure has a smaller threshold gain, a moderate strength of single-transverse-mode operation, a high quality of emission beam free...

  9. Photon losses in cosmic ray acceleration in active galactic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Colgate, S.A.

    1984-01-01

    The usual assumption of the acceleration of ultrahigh energy cosmic rays, greater than or equal to 10/sup 18/ eV in quasars, Seyfert galaxies, and other active galactic nuclei is challenged on the basis of the photon interactions with the accelerated nucleons. This is similar to the effect of the black body radiation on particles > 10/sup 20/ eV for times of the age of the universe except that the photon spectrum is harder and the energy density greater by approx. = 10/sup 13/. Hence, a single traversal, radial or circumferential, of radiation whose energy density is no greater than the emitted flux will damp an ultrahigh energy cosmic ray 10/sup 20/ eV by greater than 10/sup 4/ times its energy. Hence, it is unlikely that any reasonable configuration of acceleration can avoid disastrous photon energy loss. A different site for ultrahigh energy cosmic ray acceleration must be found.

  10. Energy response improvement for photon dosimetry using pulse analysis

    Science.gov (United States)

    Zaki, Dizaji H.

    2016-02-01

    During the last few years, active personal dosimeters have been developed and have replaced passive personal dosimeters in some external monitoring systems, frequently using silicon diode detectors. Incident photons interact with the constituents of the diode detector and produce electrons. These photon-induced electrons deposit energy in the detector's sensitive region and contribute to the response of diode detectors. To achieve an appropriate photon dosimetry response, the detectors are usually covered by a metallic layer with an optimum thickness. The metallic cover acts as an energy compensating shield. In this paper, a software process is performed for energy compensation. Selective data sampling based on pulse height is used to determine the photon dose equivalent. This method is applied to improve the energy response in photon dosimetry. The detector design is optimized for the response function and determination of the photon dose equivalent. Photon personal dose equivalent is determined in the energy range of 0.3-6 MeV. The error values of the calculated data for this wide energy range and measured data for 133Ba, 137Cs, 60Co and 241Am-Be sources respectively are up to 20% and 15%. Fairly good agreement is seen between simulation and dose values obtained from our process and specifications from several photon sources.

  11. Analysis of photon-mediated entanglement between distinguishable matter qubits

    CERN Document Server

    Dyckovsky, A M

    2012-01-01

    We theoretically evaluate establishing remote entanglement between distinguishable matter qubits through interference and detection of two emitted photons. The fidelity of the entanglement operation is analyzed as a function of the temporal and frequency mode-matching between the photons emitted from each quantum memory. With a general analysis, we define limits on the absolute magnitudes of temporal and frequency mode-mismatches in order to maintain entanglement fidelities greater than 99% with two-photon detection efficiencies greater than 90%. We apply our analysis to several selected systems of quantum memories. Results indicate that high fidelities may be achieved in each system using current experimental techniques, while maintaining acceptable rates of entanglement. Thus, it might be possible to use two-photon-mediated entanglement operations between distinguishable quantum memories to establish a network for quantum communication and distributed quantum computation.

  12. Photonic network R and D activities in Japan

    Science.gov (United States)

    Kitayama, Ken-ichi; Miki, Tetsuya; Morioka, Toshio; Tsushima, Hideaki; Koga, Masafumi; Mori, Kazuyuki; Araki, Soichiro; Sato, Ken-ichi; Onaka, Hiroshi; Namiki, Shu; Aovama, Tomonori

    2005-11-01

    R and D activities on photonic networks in Japan are presented. First, milestones in current, ongoing R and D programs supported by Japanese government agencies are introduced, including long-distance and WDM fiber transmission, wavelength routing, optical burst switching, and control plane technology for IP backbone networks. Their goal was set to evolve a legacy telecommunications network to IP over WDM networks by introducing technologies for WDM and wavelength routing. We then discuss the perspectives of so-called PHASE II R and D programs for photonic networks over the next five years until 2010, by focusing on the report which has been recently issued by the Photonic Internet Forum (PIF), a consortium that has major carriers, telecom vendors, and Japanese academics as members. The PHASE II R and D programs should serve to establish a photonic platform to provide abundant bandwidth on demand, at any time on a real-time basis through the customer's initiative, to promote bandwidth-rich applications, such as grid computing, real-time digital-cinema streaming, medical and educational applications, and network storage in e-commerce.

  13. Category theoretic analysis of single-photon decision maker

    CERN Document Server

    Kim, Makoto Naruse Song-Ju; Berthel, Martin; Drezet, Aurélien; Huant, Serge; Hori, Hirokazu

    2016-01-01

    Decision making is a vital function in the era of artificial intelligence; however, its physical realizations and their theoretical fundamentals are not yet known. In our former study [Sci. Rep. 5, 513253 (2015)], we demonstrated that single photons can be used to make decisions in uncertain, dynamically changing environments. The multi-armed bandit problem was successfully solved using the dual probabilistic and particle attributes of single photons. Herein, we present the category theoretic foundation of the single-photon-based decision making, including quantitative analysis that agrees well with the experimental results. The category theoretic model unveils complex interdependencies of the entities of the subject matter in the most simplified manner, including a dynamically changing environment. In particular, the octahedral structure in triangulated categories provides a clear understanding of the underlying mechanisms of the single-photon decision maker. This is the first demonstration of a category the...

  14. Theory of carrier depletion and light amplification in active slow light photonic crystal waveguides

    DEFF Research Database (Denmark)

    Chen, Yaohui; Mørk, Jesper

    2013-01-01

    Using a perturbative approach, we perform a quantitative three-dimensional analysis of slow-light enhanced traveling wave amplification in an active semiconductor photonic crystal waveguide. The impact of slow-light propagation on the carrier-depletion-induced nonlinear gain saturation of the...... device is investigated. An effective rate-equation-based model is presented. It is shown that it well accounts for the three-dimensional simulation results. Simulations indicate that a slow-light-enhanced photonic crystal traveling-wave amplifier has a high small-signal modal gain and low saturation...

  15. Vibration analysis of the photon shutter designed for the advanced photon source

    International Nuclear Information System (INIS)

    The photon shutter is a critical component of the beamline front end for the 7 GeV Advanced Photon Source (APS) project, now under construction at Argonne National Laboratory (ANL). The shutter is designed to close in tens of milliseconds to absorb up to 10 kW heat load (with high heat flux). Our shutter design uses innovative enhanced heat transfer tubes to withstand the high heat load. Although designed to be light weight and compact, the very fast movement of the shutter gives rise to concern regarding vibration and dynamic sensitivity. To guarantee long-term functionality and reliability of the shutter, the dynamic behavior should be fully studied. In this paper, the natural frequency and transient dynamic analysis for the shutter during operation are presented. Through analysis of the vibration characteristics, as well as stress and deformation, several options in design were developed and compared, including selection of materials for the shutter and structural details

  16. Entangling Color-Different Photons via Time-Resolved Measurement and Active Feed-Forward

    CERN Document Server

    Zhao, Tian-Ming; Yang, Jian; Sang, Zi-Ru; Jiang, Xiao; Bao, Xiao-Hui; Pan, Jian-Wei

    2015-01-01

    Entangling independent photons is not only of fundamental interest but also of crucial importance for quantum information science. Two-photon interference is a major method to entangle independent identical photons. If two photons are color-different, perfect two-photon coalescence cannot happen anymore, which makes the entangling of color-different photons difficult to realize. In this letter by exploring and developing time-resolved measurement and active feed-forward, we have entangled two independent photons of different colors for the first time. We find that entanglement with a varying form can be identified for different two-photon temporal modes through time-resolved measurement. By using active feed-forward we are able to convert the varying entanglement into uniform. Adopting these measures, we have successfully entangled two photons with a frequency separation of 16 times larger than their linewidths. In addition to its fundamental interest, our work also provides an approach to solve the frequency...

  17. Photonic crystals as templates and active devices for cellular and molecular interactions

    Science.gov (United States)

    Sonek, G. J.

    2005-04-01

    Photonic crystals are emerging as an important class of engineered nanophotonic devices that possess unique optical properties and which can also provide textured surfaces for the study and control of cellular and molecular interactions. From among the many types of photonic crystal structures, two-dimensional (2D) and planar (slab) photonic crystals are the most attractive because of their ability to support guided-wave and active optical devices in semiconductor and polymer materials, serve as templates for device replication, and interface with colloidal and nanoparticle systems. This paper reports on the results of modeling and design efforts that show how 2d and slab silicon photonic crystals, based on their in-plane optical waveguiding and out-of-plane radiation properties, might be used to probe surface-bound cells and molecules or perform localized spectroscopy. The results of a parametric analysis show that photonic crystals comprised of high-index contrast materials (e.g. Si, air) are sensitive to geometric and material factors, potentially making them an effective medium to study molecular and cellular interactions critical to a number of biotechnological applications

  18. Photon-axion conversion in Active Galactic Nuclei?

    CERN Document Server

    Bassan, Nicola

    2009-01-01

    Axion-Like Particles (ALPs) are the focus of intense current research. We analyze photon-ALP conversion in the context of relativistic jet models of Active Galactic Nuclei (AGN) for more than 100 sources. Contrary to previous claims, we find that this process cannot occur above 100 GeV regardless of the actual AGN model and the values of ALP parameters. This result rules out a proposed strategy to bypass the cosmic opacity above 100 GeV, as apparently required by observations. We also show that for some AGN an observable effect can show up in the X and soft gamma-ray bands.

  19. Theoretical analysis of an all-photonic multifunctional molecular logic device: Using TD-DFT//DFT to assess photochromic activity of multimeric photochrome

    Science.gov (United States)

    Belfon, Kellon A. A.; Gough, Jonathan D.

    2013-10-01

    The structures and properties of a single-molecule photochromic switch consisting of 3 photochromic moieties is investigated. Using time-dependent density functional theory (TD-DFT) we calculated the λmax within ± 30 nm (± 0.18 eV) and produced spectra that were similar. The charge-transfer (CT) character of the molecular orbitals (MO) was assessed via the overlap between the occupied and virtual orbitals (Λ diagnostic) and did not suffer from CT failure. The MOs were consistent with photochemically productive photochromes. The MO and their contribution to different excited states paralleled both the observed activity and observed inactivity of the photochrome.

  20. Forensic activation analysis

    International Nuclear Information System (INIS)

    Basic principles of neutron activation analysis are outlined. Examples of its use in police science include analysis for gunshot residues, toxic element determinations and multielement comparisons. Advantages of neutron activation analysis over other techniques are described. (R.L.)

  1. Local slope analysis: a new tool to study hard photon spectra

    International Nuclear Information System (INIS)

    A simple method of analysis of hard photon spectra based on the evaluation of local slope parameters is presented. The method has been applied to the experimental photon spectra from heavy ion collisions. (K.A.)

  2. Neutron Activation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Corliss, William R.

    1968-01-01

    In activation analysis, a sample of an unknown material is first irradiated (activated) with nuclear particles. In practice these nuclear particles are almost always neutrons. The success of activation analysis depends upon nuclear reactions which are completely independent of an atom's chemical associations. The value of activation analysis as a research tool was recognized almost immediately upon the discovery of artificial radioactivity. This book discusses activation analysis experiments, applications and technical considerations.

  3. Terahertz Active Photonic Crystals for Condensed Gas Sensing

    Directory of Open Access Journals (Sweden)

    Karl Unterrainer

    2011-06-01

    Full Text Available The terahertz (THz spectral region, covering frequencies from 1 to 10 THz, is highly interesting for chemical sensing. The energy of rotational and vibrational transitions of molecules lies within this frequency range. Therefore, chemical fingerprints can be derived, allowing for a simple detection scheme. Here, we present an optical sensor based on active photonic crystals (PhCs, i.e., the pillars are fabricated directly from an active THz quantum-cascade laser medium. The individual pillars are pumped electrically leading to laser emission at cryogenic temperatures. There is no need to couple light into the resonant structure because the PhC itself is used as the light source. An injected gas changes the resonance condition of the PhC and thereby the laser emission frequency. We achieve an experimental frequency shift of 10−3 times the center lasing frequency. The minimum detectable refractive index change is 1.6 × 10−5 RIU.

  4. 124Sb - Activity measurement and determination of photon emission intensities

    International Nuclear Information System (INIS)

    The international traceability of antimony 124, in term of activity, is very limited. The results of 124Sb activity measurements sent to the SIR (BIPM - International System of Reference, BIPM.RI(II)-K1.Sb-124.) are scarce. Up to now, only three laboratories have contributed. Two of them carried out measurements using the 4πβ-γ coincidence counting technique and the third one using the 4πγ method with a well-type crystal detector. The first two results are in agreement but the last one differs significantly from them, by 2 %. The decay scheme consistency cannot be excluded when trying to explain those discrepancies. In other respects, this nuclide emits high-energy gamma rays, and then could be selected as a valuable standard radionuclide for the calibration of gamma-ray detectors in that energy range, given well known photon intensities. Those considerations led to the proposal of an international exercise and to the realisation of this Euromet project, registered as project no. 907, coordinated by CEA-List-LNE/LNHB. The first part of this exercise was dedicated to activity measurements and to their comparison. For this purpose, participants were asked to make use of all the direct measurement techniques available in their laboratory in order to confirm or not the existence of possible biases specific to some measuring methods. In addition, this exercise offered the opportunity of improving the uncertainties of the gamma-ray intensities. Then, participants were asked, in the second part of the exercise, to carry out X-ray and gamma-ray intensity measurements. These results have been compared to previous published values and new decay scheme data are proposed. Eight international laboratories participated in this exercise. (authors)

  5. Two-Photon Enzymatic Probes Visualizing Sub-cellular/Deep-brain Caspase Activities in Neurodegenerative Models.

    Science.gov (United States)

    Qian, Linghui; Zhang, Cheng-Wu; Mao, Yanli; Li, Lin; Gao, Nengyue; Lim, Kah-Leong; Xu, Qing-Hua; Yao, Shao Q

    2016-01-01

    Caspases work as a double-edged sword in maintaining cell homeostasis. Highly regulated caspase activities are essential during animal development, but dysregulation might lead to different diseases, e.g. extreme caspase activation is known to promote neurodegeneration. At present, visualization of caspase activation has mostly remained at the cellular level, in part due to a lack of cell-permeable imaging probes capable of direct, real-time investigations of endogenous caspase activities in deep tissues. Herein, we report a suite of two-photon, small molecule/peptide probes which enable sensitive and dynamic imaging of individual caspase activities in neurodegenerative models under physiological conditions. With no apparent toxicity and the ability of imaging endogenous caspases both in different subcellular organelles of mammalian cells and in brain tissues, these probes serve as complementary tools to conventional histological analysis. They should facilitate future explorations of caspases at molecular, cellular and organism levels and inspire development of novel two-photon probes against other enzymes. PMID:27210613

  6. Photon activation therapy with 127I-deoxyuridine: measurement of dose enhancement in cultured mammalian cells

    International Nuclear Information System (INIS)

    A technique for radiation enhancement of conventional photon radiotherapy is outlined which has been called photon activation therapy (PAT) (6). High linear energy transfer (LET) radiations in the form of Auger electron distributions are generated by photons of appropriate energies, through photon activation of stable iodine incorporated as an analog of thymidine (Tyd) in DNA. Of the several halogenated deoxyribonucleosides evaluated, iodinated deoxyuridine (IdUrd) has been chosen as the only Tyd analog providing effective photon activation. This mechanism is combined with radiation sensitization produced by IdUrd to produce an overall radiation enhancement. Calculations show that at 5% replacement (IdUrd for Tyd) therapeutic (TG) will vary from ∼2 (single acute dose) to ∼17 (low dose rates associated with permanent implant brachytherapy). Parameters used in the calculation of TG have been evaluated in cell culture; dose enhancements obtained with x-rays (including photon activation) were found to be significantly higher than values measured with γ-rays (no photon activation). Comparison is made between theoretical and measured values. Because of the evident lack of repair of damage produced by both sensitization and photon activation, significant gains are expected to be realized following protracted irradiations. Exchanges (IdUrd for Tyd) for 105 have been obtained in vivo (murine tumors). The authors believe that the application of PAT would be most advantageous in the treatment of brain tumors (grade IV astrocytomas) with implanted 145Sm sources

  7. Slow-light-enhanced gain in active photonic crystal waveguides

    DEFF Research Database (Denmark)

    Ek, Sara; Hansen, Per Lunnemann; Chen, Yaohui;

    2014-01-01

    , which would have interesting application prospects, for example enabling ultra-compact optical amplifiers for integration in photonic chips. Here we experi- mentally investigate the gain of a photonic crystal membrane structure with embedded quantum wells. We find that by solely changing the photonic...... crystal structural parameters, the maximum value of the gain coefficient can be increased compared with a ridge waveguide structure and at the same time the spectral position of the peak gain be controlled. The experimental results are in qualitative agreement with theory and show that gain values similar...

  8. Two-photon imaging and analysis of neural network dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Luetcke, Henry; Helmchen, Fritjof [Brain Research Institute, University of Zurich, Winterthurerstrasse 190, CH-8057 Zurich (Switzerland)

    2011-08-15

    The glow of a starry night sky, the smell of a freshly brewed cup of coffee or the sound of ocean waves breaking on the beach are representations of the physical world that have been created by the dynamic interactions of thousands of neurons in our brains. How the brain mediates perceptions, creates thoughts, stores memories and initiates actions remains one of the most profound puzzles in biology, if not all of science. A key to a mechanistic understanding of how the nervous system works is the ability to measure and analyze the dynamics of neuronal networks in the living organism in the context of sensory stimulation and behavior. Dynamic brain properties have been fairly well characterized on the microscopic level of individual neurons and on the macroscopic level of whole brain areas largely with the help of various electrophysiological techniques. However, our understanding of the mesoscopic level comprising local populations of hundreds to thousands of neurons (so-called 'microcircuits') remains comparably poor. Predominantly, this has been due to the technical difficulties involved in recording from large networks of neurons with single-cell spatial resolution and near-millisecond temporal resolution in the brain of living animals. In recent years, two-photon microscopy has emerged as a technique which meets many of these requirements and thus has become the method of choice for the interrogation of local neural circuits. Here, we review the state-of-research in the field of two-photon imaging of neuronal populations, covering the topics of microscope technology, suitable fluorescent indicator dyes, staining techniques, and in particular analysis techniques for extracting relevant information from the fluorescence data. We expect that functional analysis of neural networks using two-photon imaging will help to decipher fundamental operational principles of neural microcircuits.

  9. Two-photon imaging and analysis of neural network dynamics

    Science.gov (United States)

    Lütcke, Henry; Helmchen, Fritjof

    2011-08-01

    The glow of a starry night sky, the smell of a freshly brewed cup of coffee or the sound of ocean waves breaking on the beach are representations of the physical world that have been created by the dynamic interactions of thousands of neurons in our brains. How the brain mediates perceptions, creates thoughts, stores memories and initiates actions remains one of the most profound puzzles in biology, if not all of science. A key to a mechanistic understanding of how the nervous system works is the ability to measure and analyze the dynamics of neuronal networks in the living organism in the context of sensory stimulation and behavior. Dynamic brain properties have been fairly well characterized on the microscopic level of individual neurons and on the macroscopic level of whole brain areas largely with the help of various electrophysiological techniques. However, our understanding of the mesoscopic level comprising local populations of hundreds to thousands of neurons (so-called 'microcircuits') remains comparably poor. Predominantly, this has been due to the technical difficulties involved in recording from large networks of neurons with single-cell spatial resolution and near-millisecond temporal resolution in the brain of living animals. In recent years, two-photon microscopy has emerged as a technique which meets many of these requirements and thus has become the method of choice for the interrogation of local neural circuits. Here, we review the state-of-research in the field of two-photon imaging of neuronal populations, covering the topics of microscope technology, suitable fluorescent indicator dyes, staining techniques, and in particular analysis techniques for extracting relevant information from the fluorescence data. We expect that functional analysis of neural networks using two-photon imaging will help to decipher fundamental operational principles of neural microcircuits.

  10. Photonic Network R&D Activities in Japan-Current Activities and Future Perspectives

    Science.gov (United States)

    Kitayama, Ken-Ichi; Miki, Tetsuya; Morioka, Toshio; Tsushima, Hideaki; Koga, Masafumi; Mori, Kazuyuki; Araki, Soichiro; Sato, Ken-Ichi; Onaka, Hiroshi; Namiki, Shu; Aoyama, Tomonori

    2005-10-01

    R&D activities on photonic networks in Japan are presented. First, milestones in current ongoing R&D programs supported by Japanese government agencies are introduced, including long-distance and wavelength division multiplexing (WDM) fiber transmission, wavelength routing, optical burst switching (OBS), and control-plane technology for IP backbone networks. Their goal was set to evolve a legacy telecommunications network to IP-over-WDM networks by introducing technologies for WDM and wavelength routing. We then discuss the perspectives of so-called PHASE II R&D programs for photonic networks over the next 5 years until 2010, by focusing on the report that has been recently issued by the Photonic Internet Forum (PIF), a consortium that has major carriers, telecom vendors, and Japanese academics as members. The PHASE II R&D programs should serve to establish a photonic platform to provide abundant bandwidth on demand, at any time on a real-time basis, through the customer's initiative to promote bandwidth-rich applications, such as grid computing, real-time digital-cinema streaming, medical and educational applications, and network storage in e-commerce.

  11. Two-Photon Cavity Solitons in Active Optical Media

    International Nuclear Information System (INIS)

    We show that broad-area cascade lasers with no absorbing intracavity elements support the spontaneous formation of two-dimensional bright localized structures in a dark background. These cavity solitons consist of islands of two-photon emission embedded in a background of single-photon emission. We discuss the mechanisms through which these structures are formed and interact, along with their properties and stability

  12. Slow-light enhanced gain in active photonic crystal waveguides

    OpenAIRE

    Ek, Sara; Lunnemann, Per; Chen, Yaohui; Semenova, Elizaveta; Yvind, Kresten; Mørk, Jesper

    2014-01-01

    Slow light is a fascinating physical effect, raising fundamental questions related to our understanding of light-matter interactions as well as offering new possibilities for photonic devices. From the first demonstrations of slow light propagation in ultra-cold atomic gasses, solid-state Ruby and photonic crystal structures, focus has shifted to applications, with slow light offering the ability to enhance and control light-matter interactions. The demonstration of tuneable delay lines, enha...

  13. Photon activation therapy: a Monte Carlo study on dose enhancement by various sources and activation media

    International Nuclear Information System (INIS)

    In the present study, a number of brachytherapy sources and activation media were simulated using MCNPX code and the results were analyzed based on the dose enhancement factor values. Furthermore, two new brachytherapy sources (131Cs and a hypothetical 170Tm) were evaluated for their application in photon activation therapy (PAT). 125I, 103Pd, 131Cs and hypothetical 170Tm brachytherapy sources were simulated in water and their dose rate constant and the radial dose functions were compared with previously published data. The sources were then simulated in a soft tissue phantom which was composed of Ag, I, Pt or Au as activation media uniformly distributed in the tumour volume. These simulations were performed using the MCNPX code, and dose enhancement factor (DEF) was obtained for 7, 18 and 30 mg/ml concentrations of the activation media. Each source, activation medium and concentration was evaluated separately in a separate simulation. The calculated dose rate constant and radial dose functions were in agreement with the published data for the aforementioned sources. The maximum DEF was found to be 5.58 for a combination of the 170Tm source with 30 mg/ml concentration of I. The DEFs for 131Cs and 170Tm sources for all the four activation media were higher than those for other sources and activation media. From this point of view, these two sources can be more useful in photon activation therapy with photon emitter sources. Furthermore, 131Cs and 170Tm brachytherapy sources can be proposed as new options for use in the field of PAT.

  14. Systematic approach for tolerance analysis of photonic systems

    Science.gov (United States)

    van Gurp, J. F. C.; Tichem, M.; Staufer, U.

    2011-08-01

    Passive alignment of photonic components is an assembly method compatible with a high production volume. Its precision performance relies completely on the dimensional accuracies of geometrical alignment features. A tolerance analysis plays a key role in designing and optimizing these passive alignment features. The objective of this paper is to develop a systematic approach for conducting such tolerance analysis, starting with a conceptual package design, setting up the tolerance chain, describing it mathematically and converting the misalignment to a coupling loss probability distribution expressed in dB. The method has successfully been applied to a case study where an indium phosphide (InP) chip is aligned with a TriPleX1 (SiO2 cladding with Si3N4 core) interposer via a silicon optical bench (SiOB).

  15. Band Structure Based Analysis of Certain Photonic Crystal Structures

    OpenAIRE

    Wolff, Christian

    2011-01-01

    Photonic crystals are periodic dielectric structures that may exhibit a complete photonic band gap. First, I discuss geometric properties of the band structure such as band edges. In a second part, I present work on photonic Wannier functions and their use for solving the wave equation. The third part is devoted to applications of the presented methods: A polarization resolved transmission experiment of opel films and an analogy experiment for spontaneous emission inside a photonic crystal.

  16. Analysis of photonic crystal double heterostructure resonant cavities

    Science.gov (United States)

    Mock, Adam

    Two-dimensional photonic crystals represent a versatile technology platform for constructing photonic integrated circuits. Low-loss and small footprint waveguides and cavities can be combined to make delay lines, modulators, filters and lasers for efficient optical signal processing. However, this diverse functionality comes at the expense of higher complexity in both the fabrication and themodeling of these devices. This Thesis discusses the finite-difference time-domain numerical modeling of large quality factor photonic crystal cavities for chip-scale laser applications. In Chapter 2 the role of the quality factor in estimating laser threshold is derived starting from Maxwell's equations. Expressions for modal loss and gain are derived. Chapter 3 discusses methods for extracting the quality factor from finite-difference time-domain simulations. Even with large-scale parallel computing, only a short record of the time evolution of the fields can be recorded. To get around this issue, Pade functions are fitted to the available data in the frequency domain. Once the analysis tools have been described and demonstrated, they are applied to the photonic crystal double heterostructure cavity which has been shown to have quality factors in excess of one million and mode volumes on the order of a cubic wavelength. A detailed description of the spectral and modal properties of heterostructure cavities is presented, and a method for mode discrimination is discussed. The effect of heat sinking dielectric lower substrates on the optical loss of the heterostructure cavity is investigated, and it is seen that the quality factor is significantly reduced as the index of the lower substrate is increased. A modified heterostructure cavity with glide plane symmetry is shown to have significantly reduced out-of-plane leakage. An optimized design is proposed for continuous wave edge-emitting laser operation. Finally, a novel approach for laser simulation is introduced in which a

  17. Photonic encryption : modeling and functional analysis of all optical logic.

    Energy Technology Data Exchange (ETDEWEB)

    Tang, Jason D.; Schroeppel, Richard Crabtree; Robertson, Perry J.

    2004-10-01

    With the build-out of large transport networks utilizing optical technologies, more and more capacity is being made available. Innovations in Dense Wave Division Multiplexing (DWDM) and the elimination of optical-electrical-optical conversions have brought on advances in communication speeds as we move into 10 Gigabit Ethernet and above. Of course, there is a need to encrypt data on these optical links as the data traverses public and private network backbones. Unfortunately, as the communications infrastructure becomes increasingly optical, advances in encryption (done electronically) have failed to keep up. This project examines the use of optical logic for implementing encryption in the photonic domain to achieve the requisite encryption rates. This paper documents the innovations and advances of work first detailed in 'Photonic Encryption using All Optical Logic,' [1]. A discussion of underlying concepts can be found in SAND2003-4474. In order to realize photonic encryption designs, technology developed for electrical logic circuits must be translated to the photonic regime. This paper examines S-SEED devices and how discrete logic elements can be interconnected and cascaded to form an optical circuit. Because there is no known software that can model these devices at a circuit level, the functionality of S-SEED devices in an optical circuit was modeled in PSpice. PSpice allows modeling of the macro characteristics of the devices in context of a logic element as opposed to device level computational modeling. By representing light intensity as voltage, 'black box' models are generated that accurately represent the intensity response and logic levels in both technologies. By modeling the behavior at the systems level, one can incorporate systems design tools and a simulation environment to aid in the overall functional design. Each black box model takes certain parameters (reflectance, intensity, input response), and models the optical ripple

  18. Photon Sail History, Engineering, and Mission Analysis. Appendix

    Science.gov (United States)

    Matloff, Gregory L.; Taylor, Travis; Powell, Conley

    2004-01-01

    This Appendix summarizes the results of a Teledyne Brown Engineering, Inc. report to the In-Space propulsion research group of the NASA Marshall Space Flight Center (MSFC) that was authored by Taylor et al. in 2003. The subject of this report is the technological maturity, readiness, and capability of the photon solar sail to support space-exploration missions. Technological maturity for solar photon sail concepts is extremely high high for rectangular (or square) solar sail configurations due to the historical development of the rectangular design by the NASA Jet Propulsion Laboratory (JPL). L'Garde Inc., ILC Dover Inc., DLR, and many other corporations and agencies. However, future missions and mission analysis may prove that the rectangular sail design is not the best architecture for achieving mission goals. Due to the historical focus on rectangular solar sail spacecraft designs, the maturity of other architectures such as hoop-supported disks, multiple small disk arrays, parachute sails, heliogyro sails, perforated sails, multiple vane sails (such as the Planetary Society's Cosmos 1), inflated pillow sails, etc., have not reached a high level of technological readiness. (Some sail architectures are shown in Fig. A.1.) The possibilities of different sail architectures and some possible mission concepts are discussed in this Appendix.

  19. gPhoton: Time-tagged GALEX photon events analysis tools

    Science.gov (United States)

    Million, Chase C.; Fleming, S. W.; Shiao, B.; Loyd, P.; Seibert, M.; Smith, M.

    2016-03-01

    Written in Python, gPhoton calibrates and sky-projects the ~1.1 trillion ultraviolet photon events detected by the microchannel plates on the Galaxy Evolution Explorer Spacecraft (GALEX), archives these events in a publicly accessible database at the Mikulski Archive for Space Telescopes (MAST), and provides tools for working with the database to extract scientific results, particularly over short time domains. The software includes a re-implementation of core functionality of the GALEX mission calibration pipeline to produce photon list files from raw spacecraft data as well as a suite of command line tools to generate calibrated light curves, images, and movies from the MAST database.

  20. Combined photon-neutron radiography for nondestructive analysis of materials

    International Nuclear Information System (INIS)

    Combined photon-neutron radiography was investigated as a nondestructive method to determine the shape and material composition of complex objects. A system consisting of photon and neutron sources in a cone beam configuration and a 2D detector array was modeled using the MCNP5 code. Photon-to-neutron transmission ratios were determined for a car engine using 0.1, 0.5, 2.5 MeV neutrons and 0.2, 0.5, 1 MeV photons. Focusing on inherent difference between neutron and photon interactions with matter, it was possible to classify materials within the scanned object. (author)

  1. Rigorous analysis and design of compact photonic components

    Science.gov (United States)

    Cai, Jingbo

    Rigorous design of compact photonic components for planar lightwave circuits (PLCs) typically necessitates large and lengthy numerical calculations involving the solution of Maxwell's equations and enforcing proper boundary conditions. Finding ways to shorten the analysis time and to accommodate larger problem sizes without sacrificing accuracy is very important to the success of the design process. As part of my dissertation research, I implemented a rigorous design tool based on a parallelized three-dimensional (3D) Finite Difference Time Domain (FDTD) algorithm to solve optical propagation problems in PLCs. Parallelism allows problems of larger size to be handled and also reduces computational time. Other analysis methods, such as rigorous coupled wave analysis (RCWA) and angular plane wave analysis (APWA), are also used to complement FDTD analysis or to speed up the design process. Using these tools, an ultra-compact high efficiency 90 degree bend based on a hybrid photonic crystal (PhC) and conventional waveguide (CWG) structure is numerically analyzed in three dimensions. The effect of the third dimension on the optical efficiency of the bend is found to be accountable as the clipping of the three-dimensional input waveguide mode by the finite PhC region. A much more efficient analysis method than the 3D FDTD is developed based on this result for the approximate prediction of the optical efficiency of the bend. An ultra-short integrated waveguide polarization converter based on form birefringence is designed with an efficient two-stage approach which fully addresses the 3D nature of the problem. The designed converter achieves a conversion efficiency of 98% in a length of slightly over 4mum with an insertion loss less than 0.5 dB. Moreover, two different methods are adopted for the analysis of single air interface bends (SAIBs) in waveguides. One is the rigorous but time-consuming 3D FDTD method. The other, which is approximate but requires only a very short

  2. Active Photonic Crystal Switches: Modeling, Design and Experimental Characterization

    DEFF Research Database (Denmark)

    Heuck, Mikkel; Yu, Yi; Kristensen, Philip Trøst; Kuznetsova, Nadezda; Yvind, Kresten; Mørk, Jesper

    2013-01-01

    In this paper, we present recent progress in modeling, design, fabrication and experimental characterization of InP photonic crystal all-optical switches. Novel designs with increased flexibility and performance are presented, and their operation using high speed data signals is analyzed numerica......In this paper, we present recent progress in modeling, design, fabrication and experimental characterization of InP photonic crystal all-optical switches. Novel designs with increased flexibility and performance are presented, and their operation using high speed data signals is analyzed...

  3. Active III-V Semiconductor Photonic Crystal Waveguides

    DEFF Research Database (Denmark)

    Ek, Sara; Chen, Yaohui; Schubert, Martin;

    2011-01-01

    We experimentally demonstrate enhanced amplified spontaneous emission in a quantum well III-V semiconductor photonic crystal waveguide slab. The effect is described by enhanced light matter interaction with the decrease of the group velocity. These are promising results for future compact devices...... for terabit/s communication, such as miniaturised semiconductor optical amplifiers and mode-locked lasers....

  4. W-band active imaging by photonics-based synthesizer

    Science.gov (United States)

    Kanno, Atsushi; Sekine, Norihiko; Kasamatsu, Akifumi; Yamamoto, Naokatsu

    2016-05-01

    We demonstrate a nondestructive electromagnetic-wave imaging system with a photonics-based W-band synthe- sizer, traveling-wave tube amplifier and focal-plane transistor array in real time manner. High-power amplifier with multi-watts output will enhance the quality of obtained images under transmission and reflection imaging configurations.

  5. Monte Carlo Study of the Dosimetry of Small-Photon Beams Using CMOS Active Pixel Sensors

    OpenAIRE

    Jimenez Spang, F.

    2014-01-01

    Stereotactic radiosurgery is an increasingly common treatment modality that uses very small photon fields. This technique imposes high dosimetric standards and complexities that remain unsolved. In this work the dosimetric performance of CMOS active pixel sensors is presented for the measurement of small-photons beams. A novel CMOS active pixel sensor called Vanilla developed for scientific applications was used. The detector is an array of 520 × 520 pixels on a 25 μm pitch which allows up to...

  6. Terahertz wave attenuation analysis of silicon photonic crystal fiber

    International Nuclear Information System (INIS)

    Finite element method is employed to analyze terahertz wave transmission characteristic in hexagonal photonic crystal fiber. We compared the terahertz field distribution and attenuation of the proposed photonic crystal fiber for different air-hole diameter. When d/ equals to 0.95, the lowest of transmission loss is 0.0012dB/m. The simulated results show that the performance of the presented photonic crystal fiber meets with the demand of terahertz transmission.

  7. Design and analysis of a photon/safety shutter for CARS sector 14 ID beamline at the Advanced Photon Source

    International Nuclear Information System (INIS)

    A photon/safety shutter capable of stopping bremsstrahlung, white, pink, and monochromatic radiation from the APS wiggler and undulator sources is described. The shutter consists of two individually actuated but redundant block assemblies. Each block consists of a water-cooled, OFHC block thermal absorber followed by a tungsten block to stop both synchrotron and bremsstrahlung rays. The design presented here is inexpensive and spatially compact. Fatigue analysis and ANSYS thermal and stress analysis are presented. copyright 1996 American Institute of Physics

  8. Direct optical observation of disclination effects in active photonic devices

    OpenAIRE

    Snow, B.D.; Adikan, F.R.M.; J.C.Gates; Gawith, C.B.E.; Dyadyusha, A.; Major, Huw E.; Kaczmarek, M.; P.G.R.Smith

    2008-01-01

    Liquid crystals (LC) are increasingly finding uses in fields outside of display optics. Their strong electro-optic response can be used in applications such as tunable photonic devices, for example, to make tunable planar Bragg gratings. While Bragg gratings are well known as fixed wavelength reflectors, the application of a liquid crystal can convert these fixed reflectors into tunable filter elements, with potential applications in telecommunications networks [1]. We have previously demonst...

  9. Polymer/Perovskite Amplifying Waveguides for Active Hybrid Silicon Photonics.

    Science.gov (United States)

    Suárez, Isaac; Juárez-Pérez, Emilio J; Bisquert, Juan; Mora-Seró, Iván; Martínez-Pastor, Juan P

    2015-10-28

    The emission properties of hybrid halide perovskites are exploited to implement a stable and very low power operation waveguide optical amplifier integrated in a silicon platform. By optimizing its design with a poly(methyl methacrylate) (PMMA) encapsulation, this novel photonic device presents a net gain of around 10 dB cm(-1) and 3-4 nm linewidth with an energy threshold as low as 2 nJ pulse(-1) and exhibiting no degradation after one year. PMID:26331838

  10. Single photon laser altimeter data processing, analysis and experimental validation

    Science.gov (United States)

    Vacek, Michael; Peca, Marek; Michalek, Vojtech; Prochazka, Ivan

    2015-10-01

    Spaceborne laser altimeters are common instruments on-board the rendezvous spacecraft. This manuscript deals with the altimeters using a single photon approach, which belongs to the family of time-of-flight range measurements. Moreover, the single photon receiver part of the altimeter may be utilized as an Earth-to-spacecraft link enabling one-way ranging, time transfer and data transfer. The single photon altimeters evaluate actual altitude through the repetitive detections of single photons of the reflected laser pulses. We propose the single photon altimeter signal processing and data mining algorithm based on the Poisson statistic filter (histogram method) and the modified Kalman filter, providing all common altimetry products (altitude, slope, background photon flux and albedo). The Kalman filter is extended for the background noise filtering, the varying slope adaptation and the non-causal extension for an abrupt slope change. Moreover, the algorithm partially removes the major drawback of a single photon altitude reading, namely that the photon detection measurement statistics must be gathered. The developed algorithm deduces the actual altitude on the basis of a single photon detection; thus, being optimal in the sense that each detected signal photon carrying altitude information is tracked and no altitude information is lost. The algorithm was tested on the simulated datasets and partially cross-probed with the experimental data collected using the developed single photon altimeter breadboard based on the microchip laser with the pulse energy on the order of microjoule and the repetition rate of several kilohertz. We demonstrated that such an altimeter configuration may be utilized for landing or hovering a small body (asteroid, comet).

  11. 13. seminar 'Activation analysis'

    International Nuclear Information System (INIS)

    Collection of the abstracts of contributions to the seminar covering broad ranges of application of activation analysis and improvements of systems and process steps. Most of them have been prepared separately for the energy data bases. (RB)

  12. Quantum entanglement distribution with 810 nm photons through active telecommunication fibers

    OpenAIRE

    Holloway, Catherine; Meyer-Scott, Evan; Erven, Chris; Jennewein, Thomas

    2011-01-01

    We demonstrate the distribution of polarization-entangled photons for the purpose of quantum key distribution (QKD) along active telecom fibers. Entangled photon pairs of 810 nm wavelength generated by a Sagnac interferometer source were coupled into standard telecom single mode fibers. The fibers were either dark or carrying a standardized 1550 nm ethernet signals (1000BASE-ZX) with a nominal speed of 1 GBps from regular media converter devices, without any requirements on the optical power ...

  13. Analysis of measured photon returns from sodium beacons

    International Nuclear Information System (INIS)

    We describe an approach to the computation of photon returns from mesospheric sodium beacons excited by laser pulse trains and discuss as specific examples the required numbers of photons for adaptive-optical compensation of atmospheric turbulence. Computed photon return signals are compared with reported measurements for pulses that are long, short, or comparable to the D2 radiative lifetime (16 ns). Analytical approximations in good agreement with the numerical computations are derived. The results are consistent with experimental data for the different pulse durations. copyright 1998 Optical Society of America

  14. Numerical Simulation and Experimental Analysis of Photonic Band Gap in Hollow-Core Photonic Crystal Fibres

    Institute of Scientific and Technical Information of China (English)

    YUAN Jin-Hui; HOU Lan-Tian; ZHOU Gui-Yao; WEI Dong-Bin; CHEN Chao; WANG Qing-Yue; HU Ming-Lie; LIU Bo-Wen

    2008-01-01

    Based on the full-vector plane-wave method (FVPWM),a hollow-core photonic crystal fibre (HC-PCF) fabricated by using the improved stack-and-draw technique is simulated. Under given propagation constants β,several effective photonic band gaps with different sizes emerge within the visible wavelength range from 575 to 720hm.The fundamental mode and second-order mode lying in a part of PBGs are investigated.In the transmission spectrum tested,the positions of PBGs are discovered to be shifting to shorter wavelengths.The main reason is the existence of interstitial holes at nodes in the cladding region.In the later experiment,green light is observed propagating in the air-core region,and the result is more consistent with our theoretical simulation.

  15. Activation analysis in Greece

    International Nuclear Information System (INIS)

    A review of research and development on NAA as well as examples of applications of this method are presented, taken from work carried out over the last 21 years at the Radioanalytical Laboratory of the Department of Chemistry in the Greek Nuclear Research Center ''Demokritos''. Improved and faster radiochemical NAA methods have been developed for the determination of Au, Ni, Cl, As, Cu, U, Cr, Eu, Hg and Mo in several materials, for the simultaneous determination of Br and I; Mg, Sr and Ni; As and Cu; As, Sb and Hg; Mn, Sr and Ba; Cd and Zn; Se and As; Mo and Cr in biological materials. Instrumental NAA methods have also been developed for the determination of Ag, Cl and Na in lake waters, Al, Ca, Mg and V in wines, 7 trace elements in biological materials, 17 trace elements in sediments and 20 minor and trace elements in ceramics. A comprehensive computer program for routine activation analysis using Ge(Li) detectors have been worked out. A rather extended charged-particle activation analysis program is carried out for the last 10 years, including particle induced X-ray emission (PIXE) analysis, particle induced prompt gamma-ray emission analysis (PIGE), other nuclear reactions and proton activation analysis. A special neutron activation method, the delayed fission neutron counting method is used for the analysis of fissionable elements, as U, Th, Pu, in samples of the whole nuclear fuel cycle including geological, enriched and nuclear safeguards samples

  16. Multimodal microscopy and the stepwise multi-photon activation fluorescence of melanin

    Science.gov (United States)

    Lai, Zhenhua

    The author's work is divided into three aspects: multimodal microscopy, stepwise multi-photon activation fluorescence (SMPAF) of melanin, and customized-profile lenses (CPL) for on-axis laser scanners, which will be introduced respectively. A multimodal microscope provides the ability to image samples with multiple modalities on the same stage, which incorporates the benefits of all modalities. The multimodal microscopes developed in this dissertation are the Keck 3D fusion multimodal microscope 2.0 (3DFM 2.0), upgraded from the old 3DFM with improved performance and flexibility, and the multimodal microscope for targeting small particles (the "Target" system). The control systems developed for both microscopes are low-cost and easy-to-build, with all components off-the-shelf. The control system have not only significantly decreased the complexity and size of the microscope, but also increased the pixel resolution and flexibility. The SMPAF of melanin, activated by a continuous-wave (CW) mode near-infrared (NIR) laser, has potential applications for a low-cost and reliable method of detecting melanin. The photophysics of melanin SMPAF has been studied by theoretical analysis of the excitation process and investigation of the spectra, activation threshold, and photon number absorption of melanin SMPAF. SMPAF images of melanin in mouse hair and skin, mouse melanoma, and human black and white hairs are compared with images taken by conventional multi-photon fluorescence microscopy (MPFM) and confocal reflectance microscopy (CRM). SMPAF images significantly increase specificity and demonstrate the potential to increase sensitivity for melanin detection compared to MPFM images and CRM images. Employing melanin SMPAF imaging to detect melanin inside human skin in vivo has been demonstrated, which proves the effectiveness of melanin detection using SMPAF for medical purposes. Selective melanin ablation with micrometer resolution has been presented using the Target system

  17. Activation analysis in Europe: present and future perspectives

    International Nuclear Information System (INIS)

    A survey is given of the present-day European contribution to activation analysis, covering neutron activation analysis (NAA), charged particle activation analysis (CPAA) and photon activation analysis (PAA). Attention is paid to the available irradiation facilities, in particular nuclear reactors, cyclotrons and Van de Graaff accelerators, and linear electron accelerators. Mention is made of progress in fundamental fields, but the attention is especially focussed on practical applications: environmental, geochemical/cosmochemical, biological/medical, and high-purity materials. Eventually, the role of activation analysis in research projects of the Commission of the European Communities (CEC) and in the Reference Materials program of the Community Bureau of Reference (BCR) is emphasized

  18. Numerical analysis of second harmonic generation for THz-wave in a photonic crystal waveguide using a nonlinear FDTD algorithm

    Science.gov (United States)

    Saito, Kyosuke; Tanabe, Tadao; Oyama, Yutaka

    2016-04-01

    We have presented a numerical analysis to describe the behavior of a second harmonic generation (SHG) in THz regime by taking into account for both linear and nonlinear optical susceptibility. We employed a nonlinear finite-difference-time-domain (nonlinear FDTD) method to simulate SHG output characteristics in THz photonic crystal waveguide based on semi insulating gallium phosphide crystal. Unique phase matching conditions originated from photonic band dispersions with low group velocity are appeared, resulting in SHG output characteristics. This numerical study provides spectral information of SHG output in THz PC waveguide. THz PC waveguides is one of the active nonlinear optical devices in THz regime, and nonlinear FDTD method is a powerful tool to design photonic nonlinear THz devices.

  19. SLOWPOKE: neutron activation analysis

    International Nuclear Information System (INIS)

    Neutron activation analysis permits the non-destructive determination of trace elements in crude oil and its derivatives at high sensitivity (up to 10-9 g/g) and good precision. This article consists of a quick survey of the method followed by an illustration based on the results of recent work at the SLOWPOKE reactor laboratory at the Ecole Polytechnique

  20. Photon-activated charge domain in high-gain photoconductive switches

    Institute of Scientific and Technical Information of China (English)

    Wei Shi(施卫); Huiying Dai(戴慧莹); Xiaowei Sun(孙小卫)

    2003-01-01

    We report our experimental observation of charge domain oscillation in semi-insulating GaAs photoconductive semiconductor switches (PCSSs). The high-gain PCSS is intrinsically a photon-activated charge domain device. It is the photon-activated carriers that satisfy the requirement of charge domain formation on carrier concentration and device length product of 1012 cm-2. We also show that, because of the repeated process of domain formation, the domain travels with a compromised speed of electron saturation velocity and the speed of light. As a result, the transit time of charge domains in PCSS is much shorter than that of traditional Gunn domains.

  1. Jitter analysis of a superconducting nanowire single photon detector

    Directory of Open Access Journals (Sweden)

    Lixing You

    2013-07-01

    Full Text Available Jitter is one of the key parameters for a superconducting nanowire single photon detector (SNSPD. Using an optimized time-correlated single photon counting system for jitter measurement, we extensively studied the dependence of system jitter on the bias current and working temperature. The signal-to-noise ratio of the single-photon-response pulse was proven to be an important factor in system jitter. The final system jitter was reduced to 18 ps by using a high-critical-current SNSPD, which showed an intrinsic SNSPD jitter of 15 ps. A laser ranging experiment using a 15-ps SNSPD achieved a record depth resolution of 3 mm at a wavelength of 1550 nm.

  2. Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1996-03-01

    Research results of hard photon technology have been summarized as a part of novel technology development highly utilizing the quantum nature of photon. Hard photon technology refers to photon beam technologies which use photon in the 0.1 to 200 nm wavelength region. Hard photon has not been used in industry due to the lack of suitable photon sources and optical devices. However, hard photon in this wavelength region is expected to bring about innovations in such areas as ultrafine processing and material synthesis due to its atom selective reaction, inner shell excitation reaction, and spatially high resolution. Then, technological themes and possibility have been surveyed. Although there are principle proposes and their verification of individual technologies for the technologies of hard photon generation, regulation and utilization, they are still far from the practical applications. For the photon source technology, the laser diode pumped driver laser technology, laser plasma photon source technology, synchrotron radiation photon source technology, and vacuum ultraviolet photon source technology are presented. For the optical device technology, the multi-layer film technology for beam mirrors and the non-spherical lens processing technology are introduced. Also are described the reduction lithography technology, hard photon excitation process, and methods of analysis and measurement. 430 refs., 165 figs., 23 tabs.

  3. Calibration of Cherenkov detectors for monoenergetic photon imaging in active interrogation applications

    Energy Technology Data Exchange (ETDEWEB)

    Rose, P.B., E-mail: prose6@gatech.edu; Erickson, A.S., E-mail: anna.erickson@me.gatech.edu

    2015-11-01

    Active interrogation of cargo containers using monoenergetic photons offers a rapid and low-dose approach to search for shielded special nuclear materials. Cherenkov detectors can be used for imaging of the cargo provided that gamma ray energies used in interrogation are well resolved, as the case in {sup 11}B(d,n-γ){sup 12}C reaction resulting in 4.4 MeV and 15.1 MeV photons. While an array of Cherenkov threshold detectors reduces low energy background from scatter while providing the ability of high contrast transmission imaging, thus confirming the presence of high-Z materials, these detectors require a special approach to energy calibration due to the lack of resolution. In this paper, we discuss the utility of Cherenkov detectors for active interrogation with monoenergetic photons as well as the results of computational and experimental studies of their energy calibration. The results of the studies with sources emitting monoenergetic photons as well as complex gamma ray spectrum sources, for example {sup 232}Th, show that calibration is possible as long as the energies of photons of interest are distinct.

  4. Forensic Activation Analysis

    International Nuclear Information System (INIS)

    The high sensitivity of high-flux (reactor) thermal-neutron activation analysis (NAA) for the detection and quantitative measurement of a large number of elements has led, in recent years, to a considerable degree of application of the method in the area of scientific crime investigation (criminalistics). Thus, in a Forensic Activation Analysis Bibliography recently compiled by the author, some 135 publications in this field are listed - and more are appearing quite rapidly. The nondestructive character of the purely-instrumental form of the method is an added advantage in forensic work, since evidence samples involved in actual criminal cases are not destroyed during analysis, but are preserved intact for possible presentation in court. Quite aside from, or in addition to, use in court, NAA results can be very helpful in the investigative stage of particular criminal cases. The ultra sensitivity of the method often enables one to analyze evidence specimens that are too tiny for meaningful analysis by more conventional elemental analysis methods. Also, this high sensitivity often enables one to characterize, or individualize, evidence specimens as to the possibility of common origin - via the principle of multi-element trace-constituent characterization

  5. Quantum entanglement distribution with 810 nm photons through active telecommunication fibers.

    Science.gov (United States)

    Holloway, Catherine; Meyer-Scott, Evan; Erven, Chris; Jennewein, Thomas

    2011-10-10

    We demonstrate the distribution of polarization-entangled photons for the purpose of quantum key distribution (QKD) along active telecom fibers. Entangled photon pairs of 810 nm wavelength generated by a Sagnac interferometer source were coupled into standard telecom single mode fibers. The fibers were either dark or carrying a standardized 1550 nm ethernet signals (1000BASE-ZX) with a nominal speed of 1 GBps from regular media converter devices, without any requirements on the optical power or spectrum transmitted. Our system demonstrates a QKD network covering 6 km in distance with a central service provider for classical and quantum data. PMID:21997067

  6. Analysis and simulation of photon scattering and neutron capture gamma spectra

    International Nuclear Information System (INIS)

    Within this thesis two twin experiments consisting of neutron capture and photon scattering on the neighbour isotopes 77Se/78Se and 195Pt/196Pt have been analysed to gain qualitative and quantitative information about the photon strength function and level density in the respective compound nuclei. For the analysis and simulation of both experimental types a new Monte Carlo simulation using a fast and efficient, extreme statistical treatment of radiative nuclear deexcitations, was developed. Furthermore the influence of fluctuations of transition widths on photon scattering were investigated and quantified. It could be shown that those lead to an enhancement of elastic scattering processes. The data analysis of both twin experiments reveals non-Lorentzian extra E1 photon strength below the neutron separation energy.

  7. Two-Photon Activation of p-Hydroxyphenacyl Phototriggers: Toward Spatially Controlled Release of Diethyl Phosphate and ATP.

    Science.gov (United States)

    Houk, Amanda L; Givens, Richard S; Elles, Christopher G

    2016-03-31

    Two-photon activation of the p-hydroxyphenacyl (pHP) photoactivated protecting group is demonstrated for the first time using visible light at 550 nm from a pulsed laser. Broadband two-photon absorption measurements reveal a strong two-photon transition (>10 GM) near 4.5 eV that closely resembles the lowest-energy band at the same total excitation energy in the one-photon absorption spectrum of the pHP chromophore. The polarization dependence of the two-photon absorption band is consistent with excitation to the same S3 ((1)ππ*) excited state for both one- and two-photon activation. Monitoring the progress of the uncaging reaction under nonresonant excitation at 550 nm confirms a quadratic intensity dependence and that two-photon activation of the uncaging reaction is possible using visible light in the range 500-620 nm. Deprotonation of the pHP chromophore under mildly basic conditions shifts the absorption band to lower energy (3.8 eV) in both the one- and two-photon absorption spectra, suggesting that two-photon activation of the pHP chromophore may be possible using light in the range 550-720 nm. The results of these measurements open the possibility of spatially and temporally selective release of biologically active compounds from the pHP protecting group using visible light from a pulsed laser. PMID:26962676

  8. Photon damping in cosmic-ray acceleration in active galactic nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Colgate, S.A.

    1983-04-07

    The usual assumption of the acceleration of ultra high energy cosmic rays, greater than or equal to 10/sup 18/ eV in quasars, Seyfert galaxies and other active galactic nuclei is challenged on the basis of the photon interactions with the accelerated nucleons. This is similar to the effect of the black body radiation on particles > 10/sup 20/ eV for times of the age of the universe except that the photon spectrum is harder and the energy density greater by approx. = 10/sup 15/. Hence, a single traversal, radial or circumferential, of radiation whose energy density is no greater than the emitted flux will damp an ultra high energy. Hence, it is unlikely that any reasonable configuration of acceleration can void disastrous photon energy loss. A different site for ultra high energy cosmic ray acceleration must be found.

  9. A universal setup for active control of a single-photon detector

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Qin; Skaar, Johannes [Department of Electronics and Telecommunications, Norwegian University of Science and Technology, NO-7491 Trondheim (Norway); Lamas-Linares, Antía; Kurtsiefer, Christian [Centre for Quantum Technologies and Department of Physics, National University of Singapore, 3 Science Drive 2, Singapore 117543 (Singapore); Makarov, Vadim, E-mail: makarov@vad1.com [Institute for Quantum Computing and Department of Physics and Astronomy, University of Waterloo, 200 University Avenue West, Waterloo, Ontario N2L 3G1 (Canada); Gerhardt, Ilja, E-mail: ilja@quantumlah.org [Max Planck Institute for Solid State Research, Heisenbergstraße 1, D-70569 Stuttgart (Germany)

    2014-01-15

    The influence of bright light on a single-photon detector has been described in a number of recent publications. The impact on quantum key distribution (QKD) is important, and several hacking experiments have been tailored to fully control single-photon detectors. Special attention has been given to avoid introducing further errors into a QKD system. We describe the design and technical details of an apparatus which allows to attack a quantum-cryptographic connection. This device is capable of controlling free-space and fiber-based systems and of minimizing unwanted clicks in the system. With different control diagrams, we are able to achieve a different level of control. The control was initially targeted to the systems using BB84 protocol, with polarization encoding and basis switching using beamsplitters, but could be extended to other types of systems. We further outline how to characterize the quality of active control of single-photon detectors.

  10. Supermode analysis of the 18-core photonic crystal fiber laser

    Institute of Scientific and Technical Information of China (English)

    王远; 姚建铨; 郑一博; 温午麒; 陆颖; 王鹏

    2012-01-01

    The modal of 18-core photonic crystal fiber laser is discussed and calculated.And corresponding far-field distribution of the supermodes is given by Fresnel diffraction integral.For improving beam quality,the mode selection method based on the Talbot effect is introduced.The reflection coefficients are calculated,and the result shows that an in-phase supermode can be locked better at a large propagation distance.

  11. Analysis of thin-film photonic crystal microstructures

    CERN Document Server

    Pottage, J M

    2003-01-01

    Optical-scale microstructures containing thin-film photonic crystals (TFPCs) are modelled by transfer/scattering matrix methods, based on Fourier-series expansion of the optical Bloch eigenmodes. The majority of the TFPCs considered consist of 2D arrays of holes arranged in a triangular lattice, etched into high-index Al sub x Ga sub 1 sub - sub x As and placed on a low-index oxidised substrate. These TFPCs can be easily fabricated by standard electron-beam lithography techniques. Unlike most photonic crystal devices that have been proposed, our 'intra-pass-band' TFPCs would work by exploiting the somewhat surprising properties of propagating optical Bloch waves rather than directly relying on photonic bandgaps. By numerical modelling, it is demonstrated that 2D-patterned TFPCs can support highly dispersive high-Q quasi-guided and truly-guided resonant modes, and the unusual properties of these modes are explained in terms of their Bloch-wave compositions. Modal dispersion diagrams of TFPCs, showing the loci ...

  12. Study on activation analysis

    International Nuclear Information System (INIS)

    High purity aluminum has been analyzed by neutron activation analysis. The determination of copper contents is aluminum has been used to evaluate its purity level. A new sensitive method has been developed by using graphite thermal column to reduce or eliminate the interference of 24Na which is generated from 27Al (n,α) 24Na reaction by fast neutron. Influence for activity of 24Na due to above reaction is found to be between 2.3 - 2.8 %. Copper contents in the high purity aluminum come out 0.542±0.084 ppm. In addition, contents of 23 other impurity elements (<0.1 - 0.01 ppm) are measured using general method after detection limit and optimum conditions are established. (author)

  13. Photonic Activation of Plasminogen induced by low dose UVB

    DEFF Research Database (Denmark)

    Correia, Manuel Guiherme L.P. Marins; Snabe, Torben; Thiagarajan, Viruthachalam;

    2015-01-01

    products, e.g. dityrosine and N-formylkynurenine. Most of the protein fold is maintained after 10 min illumination since no major changes are observed in the near-UV CD spectrum. Far-UV CD shows loss of secondary structure after illumination (33.4% signal loss at 206 nm). Thermal unfolding CD studies show...... observed after 10 min illumination of human plasminogen. Irradiance levels used are in the same order of magnitude of the UVB solar irradiance. Activation is correlated with light induced disruption of disulphide bridges upon UVB excitation of the aromatic residues and with the formation of photochemical.......3 Å). Such proximity makes its disruption very likely, which may occur upon electron transfer from excited Trp761. Reduction of Cys737-Cys765 will result in likely conformational changes in the catalytic site. Molecular dynamics simulations reveal that reduction of Cys737-Cys765 in plasminogen leads...

  14. Analysis of photonic band-gap structures in stratified medium

    DEFF Research Database (Denmark)

    Tong, Ming-Sze; Yinchao, Chen; Lu, Yilong;

    2005-01-01

    Purpose - To demonstrate the flexibility and advantages of a non-uniform pseudo-spectral time domain (nu-PSTD) method through studies of the wave propagation characteristics on photonic band-gap (PBG) structures in stratified medium Design/methodology/approach - A nu-PSTD method is proposed in...... the occasions where the spatial distributions contain step of up to five times larger than the original size, while simultaneously the flexibility of non-uniform sampling offers further savings on computational storage. Research limitations/implications - Research has been mainly limited to the simple...

  15. Ultrasensitive and specific measurement of protease activity using functionalized photonic crystals.

    Science.gov (United States)

    Gupta, Bakul; Mai, Kelly; Lowe, Stuart B; Wakefield, Denis; Di Girolamo, Nick; Gaus, Katharina; Reece, Peter J; Gooding, J Justin

    2015-10-01

    Herein is presented a microsensor technology as a diagnostic tool for detecting specific matrix metalloproteinases (MMPs) at very low concentrations. MMP-2 and MMP-9 are detected using label free porous silicon (PSi) photonic crystals that have been made selective for a given MMP by filling the nanopores with synthetic polymeric substrates containing a peptide sequence for that MMP. Proteolytic cleavage of the peptide sequence results in a shift in wavelength of the main peak in the reflectivity spectrum of the PSi device, which is dependent on the amount of MMP present. The ability to detect picogram amounts of MMP-2 and MMP-9 released by primary retinal pigment epithelial (RPE) cells and iris pigment epithelial (IPE) cells stimulated with lipopolysaccharide (LPS) is demonstrated. It was found that both cell types secrete higher amounts of MMP-2 than MMP-9 in their stimulated state, with RPE cells producing higher amounts of MMPs than IPE cells. The microsensor performance was compared to conventional protease detection systems, including gelatin zymography and enzyme linked immunosorbent assay (ELISA). It was found that the PSi microsensors were more sensitive than gelatin zymography; PSi microsensors detected the presence of both MMP-2 and MMP-9 while zymography could only detect MMP-2. The MMP-2 and MMP-9 quantification correlated well with the ELISA. This new method of detecting protease activity shows superior performance to conventional protease assays and has the potential for translation to high-throughput multiplexed analysis. PMID:26312479

  16. On the Photonic Cellular Interaction and the Electric Activity of Neurons in the Human Brain

    International Nuclear Information System (INIS)

    The subject of Ultraweak Photon Emission (UPE) by biological systems is very fascinating, and both evidence of its effects and applications are growing rapidly due to improvements in experimental techniques. Since the relevant equipment should be ultrasensitive with high quantum efficiencies and very low noise levels, the subject of UPE is still hotly debated and some of the interpretations need stronger empirical evidence to be accepted at face value. In this paper we first review different types of interactions between light and living systems based on recent publications. We then discuss the feasibility of UPE production in the human brain. The subject of UPE in the brain is still in early stages of development and needs more accurate experimental methods for proper analysis. In this work we also discuss a possible role of mitochondria in the production of UPE in the neurons of the brain and the plausibility of their effects on microtubules (MTs). MTs have been implicated as playing an important role in the signal and information processing taking place in the mammalian (especially human) brain. Finally, we provide a short discussion about the feasible effects of MTs on electric neural activity in the human brain.

  17. Remote Maneuver of Space Debris Using Photon Pressure for Active Collision Avoidance

    Science.gov (United States)

    Smith, C.

    2014-09-01

    The Space Environment Research Corporation (SERC) is a consortium of companies and research institutions that have joined together to pursue research and development of technologies and capabilities that will help to preserve the orbital space environment. The consortium includes, Electro Optics Systems (Australia), Lockheed Martin Australia, Optus Satellite Systems (Australia), The Australian national University, RMIT University, National Institute of Information and Communications Technology (NICT, Japan) as well as affiliates from NASA Ames and ESA. SERC is also the recipient of and Australian Government Cooperative Research Centre grant. SERC will pursue a wide ranging research program including technologies to improve tracking capability and capacity, orbit determination and propagation algorithms, conjunction analysis and collision avoidance. All of these technologies will contribute to the flagship program to demonstrate active collision avoidance using photon pressure to provide remote maneuver of space debris. This project joins of the proposed NASA Lightforce concept with infrastructure and capabilities provided by SERC. This paper will describe the proposed research and development program to provide an on-orbit demonstration within the next five years for remote maneuver of space debris.

  18. Maximum likelihood-based analysis of photon arrival trajectories in single-molecule FRET

    International Nuclear Information System (INIS)

    Highlights: ► We study model selection and parameter recovery from single-molecule FRET experiments. ► We examine the maximum likelihood-based analysis of two-color photon trajectories. ► The number of observed photons determines the performance of the method. ► For long trajectories, one can extract mean dwell times that are comparable to inter-photon times. -- Abstract: When two fluorophores (donor and acceptor) are attached to an immobilized biomolecule, anti-correlated fluctuations of the donor and acceptor fluorescence caused by Förster resonance energy transfer (FRET) report on the conformational kinetics of the molecule. Here we assess the maximum likelihood-based analysis of donor and acceptor photon arrival trajectories as a method for extracting the conformational kinetics. Using computer generated data we quantify the accuracy and precision of parameter estimates and the efficiency of the Akaike information criterion (AIC) and the Bayesian information criterion (BIC) in selecting the true kinetic model. We find that the number of observed photons is the key parameter determining parameter estimation and model selection. For long trajectories, one can extract mean dwell times that are comparable to inter-photon times.

  19. Contribution of activation products to occupational exposure following treatment using high-energy photons in radiotherapy

    International Nuclear Information System (INIS)

    When high-energy photon beams are used for irradiation in radiotherapy, neutrons that are the result of photonuclear reactions create activation products that affect the occupational dose of radiotherapy staff. For the assessment of activation products in situ gamma spectroscopy was performed parallel to dose-rate measurements following irradiation, by using a high-energy photon beam from a linear accelerator Elekta Precise (Elekta, Stockholm (Sweden)) used in radiotherapy. The major identified activation products were the following radioisotopes: 2'8Al, 24Na, 56Mn, 54Mn, 187W, 64Cu and 62Cu. Based on the typical workload and dose-rate measurement, the assessed additional annual occupational dose ranged from 1.7 to 0.25 mSv. As the measured dose rate arising from the activation products rapidly decreases as a function of time, the assessed additional dose is negligible after 10 min following irradiation. To keep the occupational dose as low as reasonably achievable, it is recommended to delay entrance to the therapy room at least 2-4 min, when high-energy photons are used. This would reduce the effective dose by 30 %. (authors)

  20. Photon-activated electron hopping in a single-electron trap enhanced by Josephson radiation

    Science.gov (United States)

    Lotkhov, S. V.; Jalali-Jafari, B.; Zorin, A. B.

    2016-04-01

    Using a Josephson junction interferometer (DC SQUID) as a microwave source for irradiating a single-electron trap, both devices fabricated on the same chip, we study the process of photon-assisted tunneling as an effective mechanism of single photon detection. High sensitivity down to a very small oscillation amplitude v J ˜ 10 nV ≪ E act ≲ h f J and down to low photon absorption rates Γph ˜ (1-50) Hz, as well as a clear threshold type of operation with an activation energy Eact ˜ 400 μeV, is demonstrated for the trap with respect to the microwave photons of frequency fJ ˜ (100-200) GHz. Tunable generation is demonstrated with respect to the power and frequency of the microwave signal produced by the SQUID source biased within the subgap voltage range. A much weaker effect is observed at the higher junction voltages along the quasiparticle branch of the I-V curve; this response mostly appears due to the recombination phonons.

  1. Photon/neutron discrimination with digital pulse shape analysis

    International Nuclear Information System (INIS)

    The discrimination of photons against neutrons is a long-standing issue in nuclear instrumentation. The availability of powerful digital hardware makes it possible to use self learning algorithms to find signal classes. The research in this field is a fundamental necessity for a wide range of experimental applications. In this work digital pulse shape discrimination is implemented based on a Fuzzy C-Means Clustering algorithm. This way the determination of signal classes is achieved offline in an automated and universally applicable manner. The implementation was used to determine the minimum ADC hardware requirements for (n,γ) discrimination of signals obtained from neutron scintillation detectors of the type BC501A. The suitability of this algorithm for discrimination was validated using TOF measurements. The dependence of the Figure of Merit on external parameters such as detector high voltage, ADC sampling rate and bit resolution was investigated.

  2. Likelihood functions for the analysis of single-molecule binned photon sequences

    International Nuclear Information System (INIS)

    Graphical abstract: Folding of a protein with attached fluorescent dyes, the underlying conformational trajectory of interest, and the observed binned photon trajectory. Highlights: ►A sequence of photon counts can be analyzed using a likelihood function. ► The exact likelihood function for a two-state kinetic model is provided. ► Several approximations are considered for an arbitrary kinetic model. ► Improved likelihood functions are obtained to treat sequences of FRET efficiencies. - Abstract: We consider the analysis of a class of experiments in which the number of photons in consecutive time intervals is recorded. Sequence of photon counts or, alternatively, of FRET efficiencies can be studied using likelihood-based methods. For a kinetic model of the conformational dynamics and state-dependent Poisson photon statistics, the formalism to calculate the exact likelihood that this model describes such sequences of photons or FRET efficiencies is developed. Explicit analytic expressions for the likelihood function for a two-state kinetic model are provided. The important special case when conformational dynamics are so slow that at most a single transition occurs in a time bin is considered. By making a series of approximations, we eventually recover the likelihood function used in hidden Markov models. In this way, not only is insight gained into the range of validity of this procedure, but also an improved likelihood function can be obtained.

  3. Activation analysis in forensic studies

    International Nuclear Information System (INIS)

    Application of neutron activation analysis in forensics are grouped into 3 categories: firearms-discharge applications, elemental analysis of other nonbiological evidence materials (paint, other), and elemental analysis of biological evidence materials (multielemental analysis of hair, analysis of hair for As and Hg). 18 refs

  4. In vivo stepwise multi-photon activation fluorescence imaging of melanin in human skin

    Science.gov (United States)

    Lai, Zhenhua; Gu, Zetong; Abbas, Saleh; Lowe, Jared; Sierra, Heidy; Rajadhyaksha, Milind; DiMarzio, Charles

    2014-03-01

    The stepwise multi-photon activated fluorescence (SMPAF) of melanin is a low cost and reliable method of detecting melanin because the activation and excitation can be a continuous-wave (CW) mode near infrared (NIR) laser. Our previous work has demonstrated the melanin SMPAF images in sepia melanin, mouse hair, and mouse skin. In this study, we show the feasibility of using SMPAF to detect melanin in vivo. in vivo melanin SMPAF images of normal skin and benign nevus are demonstrated. SMPAF images add specificity for melanin detection than MPFM images and CRM images. Melanin SMPAF is a promising technology to enable early detection of melanoma for dermatologists.

  5. Four new two-photon polymerization initiators with varying donor and conjugated bridge: Synthesis and two-photon activity

    Science.gov (United States)

    Hao, Fuying; Liu, Zhaodi; Zhang, Mingliang; Liu, Jie; Zhang, Shengyi; Wu, Jieying; Zhou, Hongping; Tian, YuPeng

    2014-01-01

    A specific series of dumbbell-shaped bis-carbazoles or bis-phenothiazines dyes (1, 2, 3 and 4) constructed with styrene or biphenylethyne as the π-bridge have been synthesized and characterized. Detailed spectral properties including linear absorption, one and two-photon fluorescence properties were investigated. The results show that extending conjugated chain and introducing donors have substantial effect on their photophysical properties. Among them, two-photon absorption cross sections (σ) of the four dyes in DMF determined by the Z-scan technique are successively increased from 1 to 4 with enhancing electron-donating ability and extending conjugated chain, but electron-donating ability has larger contribution to the σ values than extending conjugated chain based on the comparison of small molecules (D-π-D). Two-photon initiation polymerization (TPIP) microfabrication experiments have been carried out using compound 4 as an initiator under irradiation of 200 fs, 76 MHz femtosecond laser at 760 nm. The results confirm that the four dyes can be effectively used as organic two-photon photopolymerization initiators.

  6. Circuit model for efficient analysis and design of photonic crystal devices

    International Nuclear Information System (INIS)

    We substitute different types of photonic crystal waveguide components by approximate transmission line circuits. The proposed distributed circuits exploit the analogy of wave propagation in photonic crystal waveguides and transmission lines. They are either cascaded to each other or inserted like stubs to imitate wave propagation within the photonic structure. Notable examples, e.g. coupled waveguide-cavity systems, sharp 90° bends, and T-junctions, are studied in detail. It is shown that analysis of the proposed circuits here can yield accurate enough results and thus substitute the brute-force numerical methods. The privilege of having analytical models is exploited to improve the performance of sharp 90° bends and T-junctions. The presented results are verified by using the standard finite-difference time domain (FDTD) method. (paper)

  7. The Physical Mechanism for Retinal Discrete Dark Noise: Thermal Activation or Cellular Ultraweak Photon Emission?

    Science.gov (United States)

    Salari, Vahid; Scholkmann, Felix; Bokkon, Istvan; Shahbazi, Farhad; Tuszynski, Jack

    2016-01-01

    For several decades the physical mechanism underlying discrete dark noise of photoreceptors in the eye has remained highly controversial and poorly understood. It is known that the Arrhenius equation, which is based on the Boltzmann distribution for thermal activation, can model only a part (e.g. half of the activation energy) of the retinal dark noise experimentally observed for vertebrate rod and cone pigments. Using the Hinshelwood distribution instead of the Boltzmann distribution in the Arrhenius equation has been proposed as a solution to the problem. Here, we show that the using the Hinshelwood distribution does not solve the problem completely. As the discrete components of noise are indistinguishable in shape and duration from those produced by real photon induced photo-isomerization, the retinal discrete dark noise is most likely due to ‘internal photons’ inside cells and not due to thermal activation of visual pigments. Indeed, all living cells exhibit spontaneous ultraweak photon emission (UPE), mainly in the optical wavelength range, i.e., 350–700 nm. We show here that the retinal discrete dark noise has a similar rate as UPE and therefore dark noise is most likely due to spontaneous cellular UPE and not due to thermal activation. PMID:26950936

  8. Active photonic sensor communication cable for field application of optical data and power transmission

    Science.gov (United States)

    Suthau, Eike; Rieske, Ralf; Zerna, Thomas

    2014-10-01

    Omitting electrically conducting wires for sensor communication and power supply promises protection for sensor systems and monitored structures against lightning or high voltages, prevention of explosion hazards, and reduction of susceptibility to tampering. The ability to photonically power remote systems opens up the full range of electrical sensors. Power-over-fiber is an attractive option in electromagnetically sensitive environments, particularly for longterm, maintenance-free applications. It can deliver uninterrupted power sufficient for elaborate sensors, data processing or even actuators alongside continuous high speed data communication for remote sensor application. This paper proposes an active photonic sensor communication system, which combines the advantages of optical data links in terms of immunity to electromagnetic interference (EMI), high bandwidth, hardiness against tampering or eavesdropping, and low cable weight with the robustness one has come to expect from industrial or military electrical connectors. An application specific integrated circuit (ASIC) is presented that implements a closed-loop regulation of the sensor power supply to guarantee continuous, reliable data communications while maintaining a highly efficient, adaptive sensor supply scheme. It is demonstrated that the resulting novel photonic sensor communication cable can handle sensors and actuators differing orders of magnitude with respect to power consumption. The miniaturization of the electro-optical converters and driving electronics is as important to the presented development as the energy efficiency of the detached, optically powered sensor node. For this reason, a novel photonic packaging technology based on wafer-level assembly of the laser power converters by means of passive alignment will be disclosed in this paper.

  9. Caged vanilloid ligands for activation of TRPV1 receptors by 1- and 2-photon excitation†

    Science.gov (United States)

    Zhao, Jun; Gover, Tony D.; Muralidharan, Sukumaran; Auston, Darryl A.; Weinreich, Daniel; Kao, Joseph P. Y.

    2008-01-01

    Nociceptive neurons in the peripheral nervous system detect noxious stimuli and report the information to the central nervous system. Most nociceptive neurons express the vanilloid receptor, TRPV1, a non-selective cation channel gated by vanilloid ligands such as capsaicin, the pungent essence of chili peppers. Here, we report the synthesis and biological application of two caged vanilloids—biologically inert precursors that, when photolyzed, release bioactive vanilloid ligands. The two caged vanilloids, Nb-VNA and Nv-VNA, are photoreleased with quantum efficiency of 0.13 and 0.041, respectively. Under flash photolysis conditions, photorelease of Nb-VNA and Nv-VNA is 95% complete in ∼40 μs and ∼125 μs, respectively. Through 1-photon excitation with ultraviolet light (360 nm), or 2-photon excitation with red light (720 nm), the caged vanilloids can be photoreleased in situ to activate TRPV1 receptors on nociceptive neurons. The consequent increase in intracellular free Ca2+ concentration ([Ca2+]i) can be visualized by laser-scanning confocal imaging of neurons loaded with the fluorescent Ca2+ indicator, fluo-3. Stimulation results from TRPV1 receptor activation, because the response is blocked by capsazepine, a selective TRPV1 antagonist. In Ca2+-free extracellular medium, photoreleased vanilloid can still elevate [Ca2+]i, which suggests that TRPV1 receptors also reside on endomembranes in neurons and can mediate Ca2+ release from intracellular stores. Notably, whole-cell voltage clamp measurements showed that flash photorelease of vanilloid can activate TRPV1 channels in < 4 msec at 22°C. In combination with 1- or 2-photon excitation, caged vanilloids are a powerful tool for probing morphologically distinct structures of nociceptive sensory neurons with high spatial and temporal precision. PMID:16605259

  10. Hard X-ray photon index as an indicator of bolometric correction in active galactic nuclei

    OpenAIRE

    Zhou, Xin-Lin; Zhao, Yong-Heng

    2010-01-01

    We propose the rest-frame 2-10 keV photon index, \\ga, acting as an indicator of the bolometric correction, \\lb/$L_{\\rm 2-10keV}$ (where \\lb~ is the bolometric luminosity and $L_{\\rm 2-10keV}$ is the rest-frame 2-10 keV luminosity), in radio-quiet active galactic nuclei (AGNs). Correlations between \\ga~ and both bolometric correction and Eddington ratio are presented, based on simultaneous X-ray, UV, and optical observations of reverberation -mapped AGNs. These correlations can be compared wit...

  11. Analysis of photon transport in biological tissue and the subsequent heating effects

    International Nuclear Information System (INIS)

    Analysis of laser interaction with matter revealed the possibilities of many industrial and therapeutic applications. This research article discusses the theoretical aspects of laser beam interaction with biological tissues. It introduces the numerical analysis of photon distribution and transport in the tissue and its bio-thermal heating effects. The Monte Carlo method has been applied to simulate the variation of photon distribution and photon fluence with the radial distance from the point of interaction as well as laser powers and tissue thickness. For a specific wavelength, the variation of diffuse reflectance with the absorption coefficient was depicted for different values of the anisotropy factor. It has also been used to simulate the bio-heat transfer to obtain the temperature variation with the heating depth. On the other hand, finite difference method (FDM) has been applied to simulate the heating effect resulted from the incident laser beam on the tissue based on Penne's bio-heat equation combined with the obtained photon distribution and transport parameters from the MC method. The heating effect of the laser beam and hence the occurred thermal damage in the tissue was depicted. A linear relationship between the temperature and the rate of thermal damage has been manifested. This result can be used as a threshold reference for various medical applications of lasers. (authors)

  12. Irradiation system for two-photon induced activation of agents in novel intraocular lenses

    Science.gov (United States)

    Klämpfl, Florian; Roth, Stephan; Schmidt, Michael

    This paper presents a newly designed irradiation system for the photochemically triggered two-photon activation of an agent loaded in novel intraocular lenses. After activation, this agent suppresses the formation of after-cataract, a very common disease after the treatment of an eye cataract by implanting an intraocular lens. For this application, intrinsic safety is also important: the laser radiation is applied to one of the most light-sensitive organs: the eye. This has to be taken into account during development of the system. Moreover, the activation uses a two-photon process so a relatively small laser focus is required. To address these issues in combination with economic requirements, a mirror based objective was designed and built, specifically tailored to these needs. Besides the laser beam guidance elements, the irradiation system consists of a camera based monitoring module and an illumination unit. While the first part of the paper shows the design of the system, the second part presents the results of the characterization of the system. The paper closes with a conclusion and an outlook discussing what further development is needed to prepare the system for treatments of human eyes.

  13. Hybrid Active-Passive Microwave Photonic Filter with High Quality Factor

    International Nuclear Information System (INIS)

    A hybrid high quality factor (Q-factor) microwave photonic filter with a cascaded active filter and a passive filter is presented and experimentally demonstrated. The active infinite impulse response filter is realized by a recirculating delay line loop with a semiconductor optical amplifier, and a much narrower 3 dB bandwidth of response peaks can be achieved. A passive finite impulse response filter is realized by an unbalance Mach–Zehnder interferometer, and it is cascaded to select the desired filter frequencies and to suppress the intermediate peaks. Compared with the purely active filter scheme, the free spectrum range and the Q-factor of the hybrid structure can be doubled. Stable operation and a high Q-factor of 362 are experimentally demonstrated

  14. Application of neutron activation analysis

    International Nuclear Information System (INIS)

    The physical basis and analytical possibilities of neutron activation analysis have been performed. The number of applications in material engineering, geology, cosmology, oncology, criminology, biology, agriculture, environment protection, archaeology, history of art and especially in chemical analysis have been presented. The place of the method among other methods of inorganic quantitative chemical analysis for trace elements determination has been discussed

  15. Multi-element determination in standard Horse Kidney and human organ tissues by instrumental thermal neutron and photon activation analyses

    International Nuclear Information System (INIS)

    The elemental abundances in the International Atomic Energy Agency standard reference material Horse Kidney (H-8) were determined in the framework of the research project on Intercomparison of Cadmium and Other Elements in IAEA Horse Kidney. Instrumental thermal-neutron and photon activation analyses were applied to the multi-element determination in this standard material. This material was then tested for use as a comparative standard for the multi-element analysis of related biological materials; human liver and kidney tissues. The National Bureau of Standards Orchard Leaves and Bovine Liver were also used as comparative standards. Merits and comments are given on the basis of their applicability and versatility as multi-element reference materials. (author)

  16. Solvent extraction technique for the analysis of thorium-230 using the Photon-Electron Rejecting Alpha Liquid Scintillation Spectrometer (PERALS)

    International Nuclear Information System (INIS)

    A solvent extraction technique has been developed to improve the analysis and recoveries for Thorium-230. The emphasis of this technique is to improve productivity and precision over ion-exchange when using the Photon-Electron Rejecting Alpha Liquid Scintillation Spectrometer (PERALS). The Department of Energy (DOE) Formerly Utilized Sites Remedial Action Program (FUSRAP) currently is involved in characterizing sites that are contaminated with alpha emitting radionuclides which can not be detected with field instrumentation. This technique and equipment demonstrates the ability to be used for in-the-field analysis for all alpha emitting radionuclides with only minor modifications of in-laboratory procedures. The PERALS system offers 99.7% detection capability which greatly reduces counting times previously required for low activity samples. The solvent extraction technique coupled with the PERALS system significantly increases sample productivity and decreases unit cost per analysis. A description of the solvent extraction technique, the analytical instrumentation, and typical applications are discussed

  17. Analysis of Precision of Activation Analysis Method

    DEFF Research Database (Denmark)

    Heydorn, Kaj; Nørgaard, K.

    1973-01-01

    The precision of an activation-analysis method prescribes the estimation of the precision of a single analytical result. The adequacy of these estimates to account for the observed variation between duplicate results from the analysis of different samples and materials, is tested by the statistic T...

  18. Analysis of effects of posture on organ doses by internal photon emitters using voxel phantoms

    International Nuclear Information System (INIS)

    In order to clarify the effects of posture on absorbed doses in organs due to internal exposures, specific absorbed fractions (SAFs) for monoenergetic photons from 0.01 to 4 MeV were calculated using two Japanese adult male phantoms, JM2 (upright) and JM (supine), whose designs were based on CT images of two postures obtained from the same person. Differences in the SAFs of JM2 and JM are within a factor of 2 in most cases although significant differences in SAFs exist in several combinations of source and target organs for low energy photons. Organ doses due to photons from the intake of unit activity of eight radionuclides (126Ba, 128Ba, 133Ba, 130Cs, 131Cs, 178W, 179W and 190W) with different biokinetics and decay characteristics were calculated from the SAFs of JM2 and JM. It was found that the organ doses in the testes, bone marrow, lower large intestine wall, lungs and stomach wall, which are important for calculating effective dose, in the two postures roughly agree, the maximum difference being 14%. These results indicate that the impact of posture on the organ doses and effective doses from internal photon emitters is not significant

  19. Advances in explosives analysis--part II: photon and neutron methods.

    Science.gov (United States)

    Brown, Kathryn E; Greenfield, Margo T; McGrane, Shawn D; Moore, David S

    2016-01-01

    The number and capability of explosives detection and analysis methods have increased dramatically since publication of the Analytical and Bioanalytical Chemistry special issue devoted to Explosives Analysis [Moore DS, Goodpaster JV, Anal Bioanal Chem 395:245-246, 2009]. Here we review and critically evaluate the latest (the past five years) important advances in explosives detection, with details of the improvements over previous methods, and suggest possible avenues towards further advances in, e.g., stand-off distance, detection limit, selectivity, and penetration through camouflage or packaging. The review consists of two parts. Part I discussed methods based on animals, chemicals (including colorimetry, molecularly imprinted polymers, electrochemistry, and immunochemistry), ions (both ion-mobility spectrometry and mass spectrometry), and mechanical devices. This part, Part II, will review methods based on photons, from very energetic photons including X-rays and gamma rays down to the terahertz range, and neutrons. PMID:26446898

  20. Software for a measuring facility for activation analysis

    International Nuclear Information System (INIS)

    A software package has been developed for an APPLE P.C. The programs are intended to control an automated measuring station for photon activation analysis at GELINA, the linear accelerator of C.B.N.M. at Geel (Belgium). They allow to set-up a measuring scheme, to execute it under computer control, to accumulate and store 2 K-spectra using a built-in ADC and to output the results as listings, plots or evaluated reports

  1. A Cascaded Incoherent Spectrum Sliced Transversal Photonic Microwave Filters-An Analysis

    OpenAIRE

    R. K. Jeyachitra; Dr.R.Sukanesh

    2010-01-01

    An analysis of the performance of a simple, incoherent spectrum sliced microwave photonic filter is presented. This filter structure is based on cascading of two incoherent fiber Fabry -Pérot filters as a slicing element of a broadband optical source. The filter performance is studied by measuring the overall Free Spectral Range, 3dB Bandwidth, Quality factor and Main Lobe to Sidelobe Suppression level for different modes of connecting the filter in cascadedconfiguration. Also simulation resu...

  2. Design and analysis of microstrip photonic band gap filter without etching ground plane

    OpenAIRE

    R. N. Baral; P. K. Singhal

    2009-01-01

    A design of microstrip photonic band gap (PBG) filter is presented in this paper. The band reject filter is compact in structure and provides accurate band gap. The proposed filter has a periodic configuration; the impedance distribution over the length of each period is varied according to a designated sinusoidal function. Both theoretical and experimental results indicate that a bandstop filter with an extremely wide bandwidth can be achieved. Detailed analysis of the frequency response of ...

  3. Stepwise multi-photon activation fluorescence reveals a new method of melanoma imaging for dermatologists

    Science.gov (United States)

    Lai, Zhenhua; Lian, Christine; Ma, Jie; Yu, Jingyi; Gu, Zetong; Rajadhyaksha, Milind; DiMarzio, Charles A.

    2014-02-01

    Previous research has shown that the stepwise multi-photon activated fluorescence (SMPAF) of melanin, activated by a continuous-wave (CW) mode near infrared (NIR) laser, is a low cost and reliable method of detecting melanin. SMPAF images of melanin in a mouse hair and a formalin fixed mouse melanoma were compared with conventional multiphoton fluorescence microscopy (MPFM) images and confocal reflectance microscopy (CRM) images, all of which were acquired at an excitation wavelength of 920 nm, to further prove the effectiveness of SMPAF in detecting melanin. SMPAF images add specificity for melanin detection to MPFM images and CRM images. Melanin SMPAF can be a promising technology to enable melanoma imaging for dermatologists.

  4. The stepwise multi-photon activation fluorescence guided ablation of melanin

    Science.gov (United States)

    Lai, Zhenhua; Gu, Zetong; DiMarzio, Charles

    2015-02-01

    Previous research has shown that the stepwise multi-photon activation fluorescence (SMPAF) of melanin, activated and excited by a continuous-wave (CW) mode near infrared (NIR) laser, is a low-cost and reliable method for detecting melanin. We have developed a device utilizing the melanin SMPAF to guide the ablation of melanin with a 975 nm CW laser. This method provides the ability of targeting individual melanin particles with micrometer resolution, and enables localized melanin ablation to be performed without collateral damage. Compared to the traditional selective photothermolysis, which uses pulsed lasers for melanin ablation, this method demonstrates higher precision and lower cost. Therefore, the SMPAF guided selective ablation of melanin is a promising tool of melanin ablation for both medical and cosmetic purposes.

  5. Passive active resonant coupler (PARC): A new platform for monolithic integration of photonic devices

    Science.gov (United States)

    Saini, Simarjeet

    The explosive growth of telecommunications and data traffic in recent years has hastened the emergence of optical communication networks. As the volume and complexity of network traffic increases, efficient methods are required for routing and distributing the associated optical signals. This in turn has put pressure on optical device technologies. Not only are new and more complex devices required, but they must also be manufactured and packaged in a cost-efficient way. Soon, there will be a shift in the paradigm from using discrete packaged devices in a module to monolithically integrated photonic circuits where multiple functions are achieved in a single chip. This offers a considerable challenge and a great opportunity for device engineers. It is the goal of this work to continue and expand the sphere of knowledge and applicability of Photonic Integrated circuits (PIC's) by proposing and demonstrating a new platform technology for monolithically integrating various active and passive optical devices. The platform, which has been named the ``Passive Active Resonant Coupler (PARC)'', utilizes single epitaxial growth and conventional fabrication schemes. PARC devices rely on coupling between vertical waveguides where each waveguide is optimized for its specific functionality. The coupling is achieved by using a new proposed scheme of resonance over some specially designed tapers. It has been shown experimentally for the first time that very high coupling efficiencies (less than 1 dB loss) can be achieved over very short lengths, typically less than 100 μm. Coupling between different kinds of active and passive waveguides has been experimentally demonstrated. A few basic PIC's such as the 1 × 2 optical switch and the 2 × 2 cross-point switch have been demonstrated by integrating active and passive waveguides using the PARC platform. The demonstrated integration work is in the 1.55 μm wavelength range using InP as a substrate. However, the PARC platform is

  6. TIBER activation analysis

    International Nuclear Information System (INIS)

    TIBER-II is an engineering test reactor designed to establish the technical feasibility for fusion, and is a U.S. option for the prospective International Thermonuclear Test Reactor (ITER). The TIBER-II baseline design has a 3 m major radius, 3.6 aspect ratio, and 1.1 MW/m2 average neutron wall loading. The inboard shield is about .5 m thick and structurally consists of tungsten alloy and PCA alloy. The outboard is 1.52 m thick and utilizes PCA as structure and beryllium as a neutron multiplier. An aqueous solution of 160 g LiNO3/liter is used throughout as a coolant and breeder. A one-dimensional cylindrical model for TIBER is used to calculate the neutron flux and the radioactivities. Activities are calculated during and after 2.5 full power years (FPY) of operation

  7. Performance of hybrid photon detector prototypes with 80% active area for the RICH counters of LHCb

    CERN Document Server

    Albrecht, E; Barber, G J; Bibby, J H; Campbell, M; Duane, A; Gys, Thierry; Montenegro, J; Piedigrossi, D; Schomaker, R; Snoeys, W; Wotton, S A; Wyllie, Ken H

    2000-01-01

    We report on the ongoing work towards a hybrid photon detector with integrated Si pixel readout for the ring imaging Cherenkov detectors of the LHCb experiment at the Large Hadron Collider at CERN. The photon detector is based on an electrostatically focussed image intensifier tube geometry where the image is de-magnified by a factor of ~5. The anode consists of a silicon pixel array, bump-bonded to a binary readout chip with matching pixel electronics. The performance of full-scale prototypes equipped with 61-pixel anodes and external analogue readout is presented. The average signal-to-noise ratio is ~11 with a peaking time of 1.2 mu s. The tube active-to-total surface ratio is 81.7%, which meets the LHCb requirements. The spatial precision is measured to be better than 90 mu m. A cluster of three such tubes has been installed in the LHCb RICH 1 prototype where Cherenkov gas rings have been successfully detected. Progress towards the encapsulation of new pixel electronics into a tube is also reported. In pa...

  8. Photon technology. Hard photon technology; Photon technology. Hard photon gijutsu

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1997-03-01

    For the application of photon to industrial technologies, in particular, a hard photon technology was surveyed which uses photon beams of 0.1-200nm in wavelength. Its features such as selective atom reaction, dense inner shell excitation and spacial high resolution by quantum energy are expected to provide innovative techniques for various field such as fine machining, material synthesis and advanced inspection technology. This wavelength region has been hardly utilized for industrial fields because of poor development of suitable photon sources and optical devices. The developmental meaning, usable time and issue of a hard photon reduction lithography were surveyed as lithography in ultra-fine region below 0.1{mu}m. On hard photon analysis/evaluation technology, the industrial use of analysis, measurement and evaluation technologies by micro-beam was viewed, and optimum photon sources and optical systems were surveyed. Prediction of surface and surface layer modification by inner shell excitation, the future trend of this process and development of a vacuum ultraviolet light source were also surveyed. 383 refs., 153 figs., 17 tabs.

  9. Activation analysis using Cornell TRIGA

    International Nuclear Information System (INIS)

    A major use of the Cornell TRIGA is for activation analysis. Over the years many varieties of samples have been analyzed from a number of fields of interest ranging from geology, archaeology and textiles. More recently the analysis has been extended to high technology materials for applications in optical and semiconductor devices. Trace analysis in high purity materials like Si wafers has been the focus in many instances, while in others analysis of major/minor components were the goals. These analysis has been done using the delayed mode. Results from recent measurements in semiconductors and other materials will be presented. In addition the near future capability of using prompt gamma activation analysis using the Cornell cold neutron beam will be discussed. (author)

  10. Dynamic analysis of multiple-photon optical processes in semiconductor quantum dots

    International Nuclear Information System (INIS)

    Semiconductor quantum dots (QDs) have been gaining much attention because of their outstanding properties for multiple-photon microscopy applications. By solving nonperturbatively the time-dependent Schroedinger equation, it has been shown that the large number of energy states densely compacted in both the conduction and valence bands of the QD greatly enhance the inter-band and intra-band optical couplings between two energy states induced by multiple photons from ultra-fast and ultra-intense lasers. The multiphoton absorption processes are further enhanced by many energy relaxation processes in commonly used semiconductors, which are generally represented by the relaxation energy in the order of tens of meV. Numerical calculation of multiphoton processes in QDs agrees with experimental demonstration. After proper designing, QDs can be activated by infrared radiation to emit radiation in the visible optical regime (up-conversion) for bioimaging applications

  11. Quasi-real-time photon pulse duration measurement by analysis of FEL radiation spectra

    Science.gov (United States)

    Engel, Robin; Düsterer, Stefan; Brenner, Günter; Teubner, Ulrich

    2016-01-01

    For photon diagnostics at free-electron lasers (FELs), the determination of the photon pulse duration is an important challenge and a complex task. This is especially true for SASE FELs with strongly fluctuating pulse parameters. However, most techniques require an extensive experimental setup, data acquisition and evaluation time, limiting the usability in all-day operation. In contrast, the presented work uses an existing approach based on the analysis of statistical properties of measured SASE FEL spectra and implements it as a software tool, integrated in FLASH’s data acquisition system. This allows the calculation of the average pulse durations from a set of measured spectral distributions with only seconds of delay, whenever high-resolution spectra are recorded. PMID:26698053

  12. Quasi-real-time photon pulse duration measurement by analysis of FEL radiation spectra.

    Science.gov (United States)

    Engel, Robin; Düsterer, Stefan; Brenner, Günter; Teubner, Ulrich

    2016-01-01

    For photon diagnostics at free-electron lasers (FELs), the determination of the photon pulse duration is an important challenge and a complex task. This is especially true for SASE FELs with strongly fluctuating pulse parameters. However, most techniques require an extensive experimental setup, data acquisition and evaluation time, limiting the usability in all-day operation. In contrast, the presented work uses an existing approach based on the analysis of statistical properties of measured SASE FEL spectra and implements it as a software tool, integrated in FLASH's data acquisition system. This allows the calculation of the average pulse durations from a set of measured spectral distributions with only seconds of delay, whenever high-resolution spectra are recorded. PMID:26698053

  13. Analysis of Photonic Networks for a Chip Multiprocessor Using Scientific Applications

    Energy Technology Data Exchange (ETDEWEB)

    Kamil, Shoaib A; Hendry, Gilbert; Biberman, Aleksandr; Chan, Johnnie; Lee, Benjamin G.; Mohiyuddin, Marghoob; Jain, Ankit; Bergman, Keren; Carloni, Luca; Kubiatowicz, John; Oliker, Leonid; Shalf, John

    2009-01-31

    As multiprocessors scale to unprecedented numbers of cores in order to sustain performance growth, it is vital that these gains are not nullified by high energy consumption from inter-core communication. With recent advances in 3D Integration CMOS technology, the possibility for realizing hybrid photonic-electronic networks-on-chip warrants investigating real application traces on functionally comparable photonic and electronic network designs. We present a comparative analysis using both synthetic benchmarks as well as real applications, run through detailed cycle accurate models implemented under the OMNeT++ discrete event simulation environment. Results show that when utilizing standard process-to-processor mapping methods, this hybrid network can achieve 75X improvement in energy efficiency for synthetic benchmarks and up to 37X improvement for real scientific applications, defined as network performance per energy spent, over an electronic mesh for large messages across a variety of communication patterns.

  14. Estimation of useful yield in surface analysis using single photon ionisation

    Science.gov (United States)

    King, B. V.; Pellin, M. J.; Moore, J. F.; Veryovkin, I. V.; Savina, M. R.; Tripa, C. E.

    2003-01-01

    Secondary ion mass spectrometry (SIMS), laser sputter neutral mass spectrometry (SNMS) and laser desorption photoionisation (LDPI) have been used to investigate the desorption of molecules from self-assembled monolayers of phenylsulphides. LDPI, using an F 2 excimer laser to single photon ionise gave the lowest fragmentation. A useful yield greater than 0.5% was found for analysis of diphenyldisulphide self-assembled monolayers. It is shown that using a free electron laser to postionise will lead, in the future, to analysis of many atoms and molecules with useful yields approaching 30%.

  15. Engineering near-infrared single-photon emitters with optically active spins in ultrapure silicon carbide

    Science.gov (United States)

    Fuchs, F.; Stender, B.; Trupke, M.; Simin, D.; Pflaum, J.; Dyakonov, V.; Astakhov, G. V.

    2015-07-01

    Vacancy-related centres in silicon carbide are attracting growing attention because of their appealing optical and spin properties. These atomic-scale defects can be created using electron or neutron irradiation; however, their precise engineering has not been demonstrated yet. Here, silicon vacancies are generated in a nuclear reactor and their density is controlled over eight orders of magnitude within an accuracy down to a single vacancy level. An isolated silicon vacancy serves as a near-infrared photostable single-photon emitter, operating even at room temperature. The vacancy spins can be manipulated using an optically detected magnetic resonance technique, and we determine the transition rates and absorption cross-section, describing the intensity-dependent photophysics of these emitters. The on-demand engineering of optically active spins in technologically friendly materials is a crucial step toward implementation of both maser amplifiers, requiring high-density spin ensembles, and qubits based on single spins.

  16. Radiochemical separations in molten salts. Determination of carbon in metals by photon activation

    International Nuclear Information System (INIS)

    A systematic study of radiochemical separations of carbon in molten salts was achieved. It combined forecasting of salt mixtures from literature data and experimental work. The basic three mixtures of the molten salts studied are the following: Pb3O4 - B2O3, NaOH -NaNO3 and H2SO4 - KIO4 with some additions of complexing agents. Selected procedures for the determination of carbon by photon activation were issued for the following samples: Ag, Al, Cr, Fe, Mg, Mo, Ni, Si, Ti, W, Zn, Zr, AlMg, AgZn and ZnMgTe. The detection limit for carbon was 10-8 g and the accuracy from 5 to 10%. Applications to solid state science are given. (author)

  17. Solid state photon upconversion utilizing thermally activated delayed fluorescence molecules as triplet sensitizer

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Tony C.; Congreve, Daniel N.; Baldo, Marc A., E-mail: baldo@mit.edu [Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States)

    2015-07-20

    The ability to upconvert light is useful for a range of applications, from biological imaging to solar cells. But modern technologies have struggled to upconvert incoherent incident light at low intensities. Here, we report solid state photon upconversion employing triplet-triplet exciton annihilation in an organic semiconductor, sensitized by a thermally activated-delayed fluorescence (TADF) dye. Compared to conventional phosphorescent sensitizers, the TADF dye maximizes the wavelength shift in upconversion due to its small singlet-triplet splitting. The efficiency of energy transfer from the TADF dye is 9.1%, and the conversion yield of sensitizer exciton pairs to singlet excitons in the annihilator is 1.1%. Our results demonstrate upconversion in solid state geometries and with non-heavy metal-based sensitizer materials.

  18. FocusStack and StimServer: a new open source MATLAB toolchain for visual stimulation and analysis of two-photon calcium neuronal imaging data

    OpenAIRE

    Dylan Richard Muir; Björn Kampa

    2015-01-01

    Two-photon calcium imaging of neuronal responses is an increasingly accessible technology for probing population responses in cortex at single cell resolution, and with reasonable and improving temporal resolution. However, analysis of two-photon data is usually performed using ad-hoc solutions. To date, no publicly available software exists for straightforward analysis of stimulus-triggered two-photon imaging experiments. In addition, the increasing data rates of two-photon acquisition syste...

  19. Mechanism Analysis of the Inverse Doppler Effect in Two-Dimensional Photonic Crystal based on Phase Evolution

    Science.gov (United States)

    Jiang, Qiang; Chen, Jiabi; Wang, Yan; Liang, Binming; Hu, Jinbing; Zhuang, Songlin

    2016-04-01

    Although the inverse Doppler effect has been observed experimentally at optical frequencies in photonic crystal with negative effective refractive index, its explanation is based on phenomenological theory rather than a strict theory. Elucidating the physical mechanism underlying the inverse Doppler shift is necessary. In this article, the primary electrical field component in the photonic crystal that leads to negative refraction was extracted, and the phase evolution of the entire process when light travels through a moving photonic crystal was investigated using static and dynamic finite different time domain methods. The analysis demonstrates the validity of the use of np (the effective refractive index of the photonic crystal in the light path) in these calculations, and reveals the origin of the inverse Doppler effect in photonic crystals.

  20. Mechanism Analysis of the Inverse Doppler Effect in Two-Dimensional Photonic Crystal based on Phase Evolution.

    Science.gov (United States)

    Jiang, Qiang; Chen, Jiabi; Wang, Yan; Liang, Binming; Hu, Jinbing; Zhuang, Songlin

    2016-01-01

    Although the inverse Doppler effect has been observed experimentally at optical frequencies in photonic crystal with negative effective refractive index, its explanation is based on phenomenological theory rather than a strict theory. Elucidating the physical mechanism underlying the inverse Doppler shift is necessary. In this article, the primary electrical field component in the photonic crystal that leads to negative refraction was extracted, and the phase evolution of the entire process when light travels through a moving photonic crystal was investigated using static and dynamic finite different time domain methods. The analysis demonstrates the validity of the use of np (the effective refractive index of the photonic crystal in the light path) in these calculations, and reveals the origin of the inverse Doppler effect in photonic crystals. PMID:27102211

  1. Statistical analysis of photons from a single terrylene molecule for the study of the energy level scheme

    International Nuclear Information System (INIS)

    Single photons from single emitters are good candidates for a high-quality single-photon source which is essential in current quantum optical experiments and applications. Because the statistics of emitted photons is mainly determined by the energy level structure of the system, knowing the correct level scheme and the transition rates between levels is of primary importance. In this work, the energy level scheme and the photon-emission statistics of a single terrylene molecule are studied by measuring the second-order correlation function and the time trace of the emitted photons. The details in the measurement and analysis are discussed, and a more advanced energy-level structure of the terrylene molecule is suggested.

  2. Packing of Large Two- and Three-Photon Activity Into Smallest Possible Unsymmetrical Fluorene Chromophores.

    Science.gov (United States)

    Kundi, Varun; Thankachan, Pompozhi Protasis

    2016-05-01

    The quantum chemical study of one-, two-, and three-photon absorption (1PA, 2PA, and 3PA) properties for a set of compact fluorene derivatives (FD) with combination of different donor and acceptor moieties on both sides of fluorene ring system is presented. The main goal of the study is to pack large two-photon (2P) and three-photon (3P) activity into smallest possible chromophore. Linear, quadratic, and cubic response time-dependent density functional theory was used to calculate 1PA, 2PA, and 3PA properties, respectively. We used CAMB3LYP/cc-pVDZ level of theory for all the property calculations. The 2P and 3P transition probabilities were recalculated using two-state model approach and found to be in good agreement with the response theory results for first excited state. To include the contributions from higher states, the three-state model was also employed to recalculate the 2P transition probabilities and found to be in excellent agreement with response theory. The 2P/3P tensor elements were also analyzed to find reasons behind large 2P/3P activities. All the orbitals involved in transition processes were studied in detail by both molecular orbital pictures (qualitatively) and overlap diagnostic Λ-values (quantitatively). The study reveals that the novel fluorene derivatives FD-12 and FD-13 have shown large 2PA cross-section values of 1100 G.M. and 1030 G.M.; and 3PA transition probabilities of 6.10 × 10(10) a.u. and 4.85 × 10(10) a.u., respectively, for transition S0 → S1. The largest 3PA transition probability of 4.04 × 10(11) a.u. was found with FD-12 for S0 → S2 excitation. The linear relationship between Λ-values and 2PA cross-section values was also studied. PMID:27054876

  3. The development of non-destructive analysis for archaeological samples using high energy synchrotron radiation and laser electron photon

    International Nuclear Information System (INIS)

    We develop the non-destructive analysis methods for archaeological samples using high energy synchrotron radiation and laser electron photon (inverse compton scattered photons). High energy synchrotron radiation is used for non destructive elemental analysis of heavy elements to efficient analysis with less overlapped peaks. Faiences which are made recently are tested as samples. Glaze has many elements and there is difference between Iran's glaze and Egypt's glaze. As a result, high energy synchrotron radiation has possibility to solve the provenance issues. Moreover, Pb and Ba, which are detected by elemental analysis, are appropriate for isotope analysis to obtain farther information. Pb and Ba can be indices for glaze and basement respectively. The elements of excavated faience will be analyzed in future. The non destructive isotope analysis using laser electron photons will be developed at the same time. (author)

  4. Active layer identification of photonic crystal waveguide biosensor chip for the detection of Escherichia coli

    Science.gov (United States)

    Painam, Balveer; Kaler, Rajinder S.; Kumar, Mukesh

    2016-07-01

    This work represents experimental and simulation analysis of photonic crystal waveguide (PCW)-based biosensor structures, which is used for detection of the Escherichia coli (E. coli) cell. A method is adopted for E. coli culture to measure length, diameter, and refractive index to finalize the structural design and to verify the suitability of PCW as a biosensor. This method is tested using DH5α strains of E. coli. The typical precisions of measurements are varied in ranges from 1.132 to 1.825 μm and from 0.447 to 0.66 μm for pathogen's length and diameter, respectively. The measured distribution of samples over length and diameter are in correlation with the measurements performed by scanning electron microscope. After obtaining average length and diameter of cylindrical shaped E. coli cell, we consider these values for simulation analysis of designed PCW biosensor. E. coli cell is trapped in the middle of the PCW biosensor having three different types of waveguides, i.e., gallium arsenide/silicon dioxide (GaAs/SiO2), silicon/silicon dioxide (Si/SiO2), or silicon nitride/silicon dioxide (Si3N4/SiO2) to observe the maximum resonance shift and sensitivity. It is observed from the simulation data analysis that GaAs/SiO2 is the preferred PCW biosensor for the identification of E. coli.

  5. Monitoring molecular interactions using photon arrival-time interval distribution analysis

    Science.gov (United States)

    Laurence, Ted A.; Weiss, Shimon

    2009-10-06

    A method for analyzing/monitoring the properties of species that are labeled with fluorophores. A detector is used to detect photons emitted from species that are labeled with one or more fluorophores and located in a confocal detection volume. The arrival time of each of the photons is determined. The interval of time between various photon pairs is then determined to provide photon pair intervals. The number of photons that have arrival times within the photon pair intervals is also determined. The photon pair intervals are then used in combination with the corresponding counts of intervening photons to analyze properties and interactions of the molecules including brightness, concentration, coincidence and transit time. The method can be used for analyzing single photon streams and multiple photon streams.

  6. Abiotic control of underwater light in a drinking water reservoir: Photon budget analysis and implications for water quality monitoring

    Science.gov (United States)

    Watanabe, Shohei; Laurion, Isabelle; Markager, Stiig; Vincent, Warwick F.

    2015-08-01

    In optically complex inland waters, the underwater attenuation of photosynthetically active radiation (PAR) is controlled by a variable combination of absorption and scattering components of the lake or river water. Here we applied a photon budget approach to identify the main optical components affecting PAR attenuation in Lake St. Charles, a drinking water reservoir for Québec City, Canada. This analysis showed the dominant role of colored dissolved organic matter (CDOM) absorption (average of 44% of total absorption during the sampling period), but with large changes over depth in the absolute and relative contribution of the individual absorption components (water, nonalgal particulates, phytoplankton and CDOM) to PAR attenuation. This pronounced vertical variation occurred because of the large spectral changes in the light field with depth, and it strongly affected the average in situ diffuse absorption coefficients in the water column. For example, the diffuse absorption coefficient for pure-water in the ambient light field was 10-fold higher than the value previously measured in the blue open ocean and erroneously applied to lakes and coastal waters. Photon absorption budget calculations for a range of limnological conditions confirmed that phytoplankton had little direct influence on underwater light, even at chlorophyll a values above those observed during harmful algal blooms in the lake. These results imply that traditional measures of water quality such as Secchi depth and radiometric transparency do not provide a meaningful estimate of the biological state of the water column in CDOM-colored lakes and reservoirs.

  7. Error-free DWDM transmission and crosstalk analysis for a silicon photonics transmitter.

    Science.gov (United States)

    Seyedi, M Ashkan; Chen, Chin-Hui; Fiorentino, Marco; Beausoleil, Ray

    2015-12-28

    Individual channels of a five-channel microring silicon photonics transmitter are used for bit error ratio analysis and demonstrate error-free transmission at 10Gb/s. Two channels of the same transmitter are concurrently modulated using an 80GHz channel spacing comb laser and demonstrate open eye diagrams at 10Gb/s and 12.5Gb/s. Finally, concurrent modulation with tunable lasers is done to quantify optical power penalty for link bit error ratio versus channel spacing from +100GHz to -100GHz. When using a comb laser for concurrent modulation, no direct power penalty is observed for an 80GHz channel separation. PMID:26831964

  8. Charged-particle activation analysis

    International Nuclear Information System (INIS)

    The paper discusses the methodology and application of nuclear activation with ion beams (19 via 16O(3He,p)18F, 12C(3He,α)11C and 14N(p,α)11C respectively. Recently, triton activation has been shown to be inherently still superior to 3He activation for the determination of oxygen [16O(3H,n)18F]. Lithium, boron, carbon and sulphur can be detected rapidly, nondestructively and with high sensitivity (approximately 0.25ppm for Li and B) via ''quasi-prompt'' activation based on the detection of short-lived, high-energy beta emitters (10ms1H(7Li,n)7Be for example. Nondestructive multielement analysis: Proton activation has the inherent potential for meeting requirements of broad elemental coverage, sensitivity (ppm and sub-ppm range) and selectivity. Up to 30 elements have been determined in Al, Co, Ag, Nb, Rh, Ta and biological samples, using 12-MeV proton activation followed by gamma-ray spectrometry. These capabilities are further enhanced with the counting of X-ray emitters, 28 elements (269) and accuracy using proton activation. 204Pb/206Pb ratios can also be determined with a relative precision of a few per cent. Although charged-particle activation analysis is a well-established trace analysis technique, broad potential capabilities remain to be explored, e.g. those arising from ultrashort-lived nuclides, heavy ion interactions and the combination of delayed and prompt methods. (author)

  9. Automated activation-analysis system

    International Nuclear Information System (INIS)

    An automated delayed neutron counting and instrumental neutron activation analysis system has been developed at Los Alamos National Laboratory's Omega West Reactor (OWR) to analyze samples for uranium and 31 additional elements with a maximum throughput of 400 samples per day. The system and its mode of operation for a large reconnaissance survey are described

  10. Neutron activation analysis of coins

    International Nuclear Information System (INIS)

    Activation analysis was applied to the study of coins using 14MeV neutrons produced by an accelerator for the determination of oxygen and neutrons emitted from a 252Cf source for the determination of the other elements (Au, Ag, Cu, As etc...). The advantages of this technique are presented

  11. Photon small-field measurements with a CMOS active pixel sensor

    International Nuclear Information System (INIS)

    In this work the dosimetric performance of CMOS active pixel sensors for the measurement of small photon beams is presented. The detector used consisted of an array of 520  × 520 pixels on a 25 µm pitch. Dosimetric parameters measured with this sensor were compared with data collected with an ionization chamber, a film detector and GEANT4 Monte Carlo simulations. The sensor performance for beam profiles measurements was evaluated for field sizes of 0.5  × 0.5 cm2. The high spatial resolution achieved with this sensor allowed the accurate measurement of profiles, beam penumbrae and field size under lateral electronic disequilibrium. Field size and penumbrae agreed within 5.4% and 2.2% respectively with film measurements. Agreements with ionization chambers better than 1.0% were obtained when measuring tissue-phantom ratios. Output factor measurements were in good agreement with ionization chamber and Monte Carlo simulation. The data obtained from this imaging sensor can be easily analyzed to extract dosimetric information. The results presented in this work are promising for the development and implementation of CMOS active pixel sensors for dosimetry applications. (paper)

  12. Photon small-field measurements with a CMOS active pixel sensor

    Science.gov (United States)

    Jiménez Spang, F.; Rosenberg, I.; Hedin, E.; Royle, G.

    2015-06-01

    In this work the dosimetric performance of CMOS active pixel sensors for the measurement of small photon beams is presented. The detector used consisted of an array of 520  × 520 pixels on a 25 µm pitch. Dosimetric parameters measured with this sensor were compared with data collected with an ionization chamber, a film detector and GEANT4 Monte Carlo simulations. The sensor performance for beam profiles measurements was evaluated for field sizes of 0.5  × 0.5 cm2. The high spatial resolution achieved with this sensor allowed the accurate measurement of profiles, beam penumbrae and field size under lateral electronic disequilibrium. Field size and penumbrae agreed within 5.4% and 2.2% respectively with film measurements. Agreements with ionization chambers better than 1.0% were obtained when measuring tissue-phantom ratios. Output factor measurements were in good agreement with ionization chamber and Monte Carlo simulation. The data obtained from this imaging sensor can be easily analyzed to extract dosimetric information. The results presented in this work are promising for the development and implementation of CMOS active pixel sensors for dosimetry applications.

  13. Sensitivity analysis for activation problems

    International Nuclear Information System (INIS)

    A study has been made about how to develop further the techniques for sensitivity analysis used by FISPACT-II. FISPACT-II is a software suite for the analysis of nuclear activation and transmutation problems, developed for all nuclear applications. The software already permits sensitivity analysis to be performed by Monte Carlo sampling, and a faster uncertainty analysis is made possible by a powerful graph-based approach which generates a reduced set of nuclides on pathways leading to significant contributions to radiological quantities. The peculiar aspects of the sensitivity analysis problem for activation are the large number, typically thousands, of rate equation parameters (decay rates and reaction cross-sections) which all have some degree of associated error, and the fact that activity as a function of time varies as a sum of exponentials, so appears discontinuous as rate parameters are varied unless the sampling frequency is impracticably fast. Nevertheless, Monte Carlo sampling is a generic approach and it is therefore conceivable that techniques more targeted to the activation problem might be beneficial. Moreover, recent theoretical developments have highlighted the importance of a two-stage approach to mathematically similar problems, where in the first stage, information is collected about the global behaviour of the problem, such as the identification of the rate parameters which cause the greatest variation in dose or nuclear activity, before a second stage examines a problem with its scope restricted by the information from the first. In the second stage, for example, Quasi-Monte Carlo sampling may be used in a restricted parameter space. The current work concentrates on the first stage and consists of a review of possible techniques with a detailed examination of the most promising pathways reduction approach, examined directly using FISPACT-II. All the evidence obtained demonstrates the strong potential of this approach. (authors)

  14. Analysis of photonic band gap in dispersive properties of tunable three-dimensional photonic crystals doped by magnetized plasma

    International Nuclear Information System (INIS)

    In this paper, the magnetooptical effects in dispersive properties for two types of three-dimensional magnetized plasma photonic crystals (MPPCs) containing homogeneous dielectric and magnetized plasma with diamond lattices are theoretically investigated for electromagnetic (EM) wave based on plane wave expansion (PWE) method, as incidence EM wave vector is parallel to the external magnetic field. The equations for two types of MPPCs with diamond lattices (dielectric spheres immersed in magnetized plasma background or vice versa) are theoretically deduced. The influences of dielectric constant, plasma collision frequency, filling factor, the external magnetic field, and plasma frequency on the dispersive properties for both types of structures are studied in detail, respectively, and some corresponding physical explanations are also given. From the numerical results, it has been shown that the photonic band gaps (PBGs) for both types of MPPCs can be manipulated by plasma frequency, filling factor, the external magnetic field, and the relative dielectric constant of dielectric, respectively. Especially, the external magnetic field can enlarge the PBG for type-2 structure (plasma spheres immersed in dielectric background). However, the plasma collision frequency has no effect on the dispersive properties of two types of three-dimensional MPPCs. The locations of flatbands regions for both types of structures cannot be tuned by any parameters except for plasma frequency and the external magnetic field. The analytical results may be informative and of technical use to design the MPPCs devices.

  15. Design and Analysis of Enhanced Modulation Response in Integrated Coupled Cavities DBR Lasers Using Photon-Photon Resonance

    Directory of Open Access Journals (Sweden)

    Paolo Bardella

    2016-01-01

    Full Text Available In the last few decades, various solutions have been proposed to increase the modulation bandwidth and, consequently, the transmission bit-rate of semiconductor lasers. In this manuscript, we discuss a design procedure for a recently proposed laser cavity realized with the monolithic integration of two distributed Bragg reflector (DBR lasers allowing one to extend the modulation bandwidth. Such an extension is obtained introducing in the dynamic response a photon-photon resonance (PPR at a frequency higher than the modulation bandwidth of the corresponding single-section laser. Design guidelines will be proposed, and dynamic small and large signal simulations results, calculated using a finite difference traveling wave (FDTW numerical simulator, will be discussed to confirm the design results. The effectiveness of the design procedure is verified in a structure with PPR frequency at 35 GHz allowing one to obtain an open eye diagram for a non-return-to-zero (NRZ digital signal up to 80 GHz . Furthermore, the investigation of the rich dynamics of this structure shows that with proper bias conditions, it is possible to obtain also a tunable self-pulsating signal in a frequency range related to the PPR design.

  16. Arrangement Analysis of Leaves Optimized on Photon Flux Density or Photosynthetic Rate

    Science.gov (United States)

    Obara, Shin'ya; Tanno, Itaru

    By clarifying a plant evolutive process, useful information may be obtained on engineering. Consequently, an analysis algorithm that investigates the optimal arrangement of plant leaves was developed. In the developed algorithm, the Monte Carlo method is introduced and sunlight is simulated. Moreover, the arrangement optimization of leaves is analyzed using a Genetic Algorithm (GA). The number of light quanta (photon flux density) that reaches leaves, or the average photosynthetic rate of the same was set as the objective function, and leaf models of a dogwood and a ginkgo tree were analyzed. The number of leaf models was set between two to four, and the position of the leaf was expressed in terms of the angle of direction, elevation angle, rotation angle, and the representative length of the branch of a leaf. The chromosome model introduced into GA consists of information concerning the position of the leaf. Based on the analysis results, the characteristics of the leaf of an actual plant could be simulated by ensuring the algorithm had multiple constrained conditions. The optimal arrangement of leaves differs in maximization of the photon flux density, and that of the average value of a photosynthetic rate. Furthermore, the leaf form affecting the optimal arrangement of leave and also having a significant influence also on a photosynthetic rate was shown.

  17. Design and analysis of a wideband photonic crystal waveguide with low group-velocity and low dispersion

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    The slow light propagation in a line waveguide in the two-dimensional triangular photonic crystal has been numerically studied, based on which a wideband photonic crystal waveguide with low group-velocity and low dispersion is proposed. The numerical simulation analysis shows that it is possible to maximize the group index and minimize the group-velocity dispersion in wide bandwidth by increasing the radius of the basic air hole and changing the position of the first two rows of air holes in photonic crystal waveguides. Such a photonic crystal waveguide exhibits low group velocity and low group-velocity dispersion over a broad wavelength range. A larger group index-bandwidth product is achieved in this type of waveguide structure. The numerically computed results present the normalized bandwidth as 0.32%, 0.48% and 0.642% corresponding to the group index of 85, 58 and 45, respectively.

  18. An Analysis Of The Three Photon Decay Of The Eta Meson With Artificial Neural Networks

    CERN Document Server

    Ramírez, A F

    2004-01-01

    A search for the three-photon decay of the eta meson utilized data collected with the Crystal Ball Spectrometer at the Alternating Gradient Synchrotron (AGS) at Brookhaven National Laboratory (BNL). The decay is forbidden to occur due to the conservation of charge conjugation by the electromagnetic interaction. Therefore, the measurement of its branching ratio is a test of the validity of this conservation law. Given the expected small size of the branching ratio, artificial neural networks (ANNs) were trained to distinguish events consistent with this rare eta decay from those produced by background processes, which dominated the data. The effectiveness of ANNs in identifying the pertinent signal was compared to that of traditional analysis techniques based on hard cuts. The technique implementing ANNs demonstrated a remarkable improvement over that using hard cuts. However, both techniques resulted in values well above the currently accepted upper limit on the branching ratio. An analysis of the events clas...

  19. Field analysis of TE and TM modes in photonic crystal Bragg fibers by transmission matrix method

    Directory of Open Access Journals (Sweden)

    M Hosseini Farzad

    2010-03-01

    Full Text Available In this article, we considered the field analysis in photonic crystal Bragg fibers. We apply the method of transmission matrix to calculater the dispersion curves, the longitudinal wave number over wave number versus incident wavelength, and the field distributions of TE and TM modes in the Bragg fiber. Our analysis shows that the field of guided modes is confined in the core and can exist only in particular wavelength bands corresponding to the band-gap of the periodic structure of the clad. From another point of view, light confinement is due to Bragg reflection from high-and low-refractive index layers of the clad. Also, the diagram of average angular frequency with respect to average longitudinal wave number is plotted so that the band gap regions of the clad are clearly observed.

  20. Quantification of Fissile Materials by Photon Activation Method in a Highly Shielded Enclosure

    International Nuclear Information System (INIS)

    For active and non-destructive quantitative identification of heavily shielded fissile materials, photo fission is one of the most often used techniques. High energy photon beams can be conveniently generated with the help of electron LINACs. 10MeV energy electron LINACs are extensively used for various industrial applications such as food irradiation, X-ray radiography, etc. The radiological safety consideration favours the use of electron beam of upto 10 MeV energy. The photonuclear data available on 10 MeV end point energy is very scarce. The present paper gives the results of our initial experiments carried out using natural uranium samples at 10 MeV LINAC facility. Water cooled tantalum target converter was used to produce intense Bremsstrahlung to induce photofission in the samples. Neutron detection system consists of six numbers of high sensitivity Helium-3 proportional counters and gamma detection system consists of two numbers of 76 mm diameter BGO scintillators. Delayed neutron and delayed gamma radiations were measured and analyzed. The mass to count rate relationship has been established for both delayed neutron and gamma radiations. Delayed gamma decay constants of natural uranium have been derived for the 10 MeV end point energy. (author)

  1. Optimization of instrumental activation analysis

    International Nuclear Information System (INIS)

    Activation analysis is one of the most well-understood methods available to the analyst. It should, therefore, be possible to infer, from prior information about the sample, what procedure should be followed in its analysis. The accuracy of this process is naturally limited by the extent and accuracy of the prior information available. Better results should be obtained in this way, however, than by ignoring prior information. It is the task of optimization to discover the analytical procedure that best suits the sample being analyzed. Optimization can be conveniently conceptualized if each experimental parameter is considered as a dimension of a geometric space. In activation analysis, if only irradiation and decay times are to be adjusted, the parameter space will be two dimensional. Each point in the parameter space corresponds to a possible procedure for carrying out a determination and each such procedure will perform more or less satisfactorily than others. Optimization, then, consists of a search for a point or a region in parameter space where performance meets the analyst's requirements. Practicality is an important consideration in designing a procedure for activation analysis. There are limits to the amount of radioactive material that can be handled safely and to the count rate that be accurately measured. Circumstances often impose further limits. It is, therefore, necessary to constrain the search of parameter space to those regions that correspond to practical procedures. In attempting an optimization, one must consider a number of aspects. A set of experimental parameters must be chosen for adjustment and others set at fixed values, often due to practical constraints. The way in which quality of analytical performance (the response function) is to be evaluated must be decided. A means of locating the optimum must be chosen and, finally, this optimization scheme must be implemented in a practical, convenient manner. These aspects are discussed

  2. Photonic crystals

    CERN Document Server

    Busch, Kurt; Wehrspohn, Ralf B; Föll, Helmut

    2006-01-01

    The majority of the contributions in this topically edited book stems from the priority program SPP 1113 ""Photonische Kristalle"" run by the Deutsche Forschungsgemeinschaft (DFG), resulting in a survey of the current state of photonic crystal research in Germany. The first part of the book describes methods for the theoretical analysis of their optical properties as well as the results. The main part is dedicated to the fabrication, characterization and modeling of two- and three-dimensional photonic crystals, while the final section presents a wide spectrum of applications: gas sensors, micr

  3. PHOTON-PHOTON COLLISIONS

    OpenAIRE

    Burke, D.

    1982-01-01

    Studies of photon-photon collisions are reviewed with particular emphasis on new results reported to this conference. These include results on light meson spectroscopy and deep inelastic eγ scattering. Considerable work has now been accumulated on resonance production by γγ collisions. Preliminary high statistics studies of the photon structure function Fγ2(x,Q2) are given and comments are made on the problems that remain to be solved.

  4. Photon-photon colliders

    Energy Technology Data Exchange (ETDEWEB)

    Sessler, A.M.

    1995-04-01

    Since the seminal work by Ginsburg, et at., the subject of giving the Next Linear Collider photon-photon capability, as well as electron-positron capability, has drawn much attention. A 1990 article by V.I. Teinov describes the situation at that time. In March 1994, the first workshop on this subject was held. This report briefly reviews the physics that can be achieved through the photon-photon channel and then focuses on the means of achieving such a collider. Also reviewed is the spectrum of backscattered Compton photons -- the best way of obtaining photons. We emphasize the spectrum actually obtained in a collider with both polarized electrons and photons (peaked at high energy and very different from a Compton spectrum). Luminosity is estimated for the presently considered colliders, and interaction and conversion-point geometries are described. Also specified are laser requirements (such as wavelength, peak power, and average power) and the lasers that might be employed. These include conventional and free-electron lasers. Finally, we describe the R&D necessary to make either of these approaches viable and explore the use of the SLC as a test bed for a photon-photon collider of very high energy.

  5. Photon-photon colliders

    International Nuclear Information System (INIS)

    Since the seminal work by Ginsburg, et at., the subject of giving the Next Linear Collider photon-photon capability, as well as electron-positron capability, has drawn much attention. A 1990 article by V.I. Teinov describes the situation at that time. In March 1994, the first workshop on this subject was held. This report briefly reviews the physics that can be achieved through the photon-photon channel and then focuses on the means of achieving such a collider. Also reviewed is the spectrum of backscattered Compton photons -- the best way of obtaining photons. We emphasize the spectrum actually obtained in a collider with both polarized electrons and photons (peaked at high energy and very different from a Compton spectrum). Luminosity is estimated for the presently considered colliders, and interaction and conversion-point geometries are described. Also specified are laser requirements (such as wavelength, peak power, and average power) and the lasers that might be employed. These include conventional and free-electron lasers. Finally, we describe the R ampersand D necessary to make either of these approaches viable and explore the use of the SLC as a test bed for a photon-photon collider of very high energy

  6. In vivo imaging of activated microglia in a mouse model of focal cerebral ischemia by two-photon microscopy

    OpenAIRE

    Bok, Seoyeon; Wang, Taejun; Lee, Chan-Ju; Jeon, Seong-Uk; Kim, Young-eun; Kim, Jeongwoo; Hong, Beom-Ju; Yoon, Calvin Jinse; Kim, Sungjee; Lee, Seung-Hoon; KIM, HAK JAE; Kim, Il Han; Kim, Ki Hean; Ahn, G-One

    2015-01-01

    Microglia are brain resident macrophages rapidly responding to various stimuli to exert appropriate inflammatory responses. Although they have recently been exploited as an attractive candidate for imaging neuroinflammation, it is still difficult to visualize them at the cellular and molecular levels. Here we imaged activated microglia by establishing intracranial window chamber (ICW) in a mouse model of focal cerebral ischemia by using two-photon microscopy (TPM), in vivo. Intravenous inject...

  7. Second harmonic generation (SHG) and two-photon fluorescence (TPF) contrast imaging in biomaterial analysis

    Science.gov (United States)

    Lang, Xuye; Lyubovitsky, Julia

    2015-07-01

    Collagen hydrogels are natural biomaterials that comprise 3D networks of high water content and have viscoelastic properties and biocompatibility similar to native tissues. Consequently, these materials play an important role in tissue engineering and regenerative medicine for quite some time. Second harmonic generation (SHG) and two-photon fluorescence (TPF) contrasts transpire as valuable label-free spectroscopic probes for analysis of these biomaterials and this presentation will report the structural, mechanical and physicochemical parameters leading to the observed optical SHG and TPF effects in synthesized 3D collagen hydrogels. We will present results regarding understanding the dependency of collagen fiber formation on ion types, new results regarding strengthening of these biomaterials with a nontoxic chemical cross-linker genipin and polarization selection of collagen fibers' orientations.

  8. A Cascaded Incoherent Spectrum Sliced Transversal Photonic Microwave Filters-An Analysis

    Directory of Open Access Journals (Sweden)

    R. K. Jeyachitra

    2010-05-01

    Full Text Available An analysis of the performance of a simple, incoherent spectrum sliced microwave photonic filter is presented. This filter structure is based on cascading of two incoherent fiber Fabry -Pérot filters as a slicing element of a broadband optical source. The filter performance is studied by measuring the overall Free Spectral Range, 3dB Bandwidth, Quality factor and Main Lobe to Sidelobe Suppression level for different modes of connecting the filter in cascadedconfiguration. Also simulation results are presented. The Characteristics of cascaded FP filters with different configurations are tabulated. The estimated performances show that this cascaded filter combination can be tuned over the frequency from 4.6GHz to 18 GHz with very good sidelobe suppression level.

  9. Instrumentation in neutron activation analysis

    International Nuclear Information System (INIS)

    The rise of neutron activation analysis (NAA) as a tool in geochemical research has parallelled advances in detector, multi-channel analyzer, and computer technology. Micro-computers are now being integrated into NAA systems, and gamma-ray spectrometer instrumentation is evolving towards direct-reading systems. The investigator is faced with a wide range of possibilities and choices when equipping or re-equipping a laboratory. The geoscientist is provided with an overview of the available instrumentation and what soon may be feasible. (L.L.)

  10. Fluorescence-quenching-based homogeneous caspase-3 activity assay using photon upconversion

    Energy Technology Data Exchange (ETDEWEB)

    Vuojola, Johanna, E-mail: johanna.vuojola@utu.fi [Department of Biotechnology, University of Turku, Tykistoekatu 6A, FI-20520 Turku (Finland); Riuttamaeki, Terhi; Kulta, Essi; Arppe, Riikka; Soukka, Tero [Department of Biotechnology, University of Turku, Tykistoekatu 6A, FI-20520 Turku (Finland)

    2012-05-06

    Highlights: Black-Right-Pointing-Pointer We demonstrate the use of photon upconversion in a caspase-3 activity assay. Black-Right-Pointing-Pointer The separation-free assay uses an internally quenched substrate peptide. Black-Right-Pointing-Pointer UCPs enable simple instrumentation and total elimination of autofluorescence. Black-Right-Pointing-Pointer A sensitive assay with high signal-to-background ratios was achieved. Black-Right-Pointing-Pointer Suitable for high-throughput screening through miniaturization and white plates. - Abstract: Caspase proteases are key mediators in apoptosis and thus of great interest in pharmaceutical industry. Enzyme-activity assays are commonly employed in the screening of protease inhibitors that are potential drug candidates. Conventional homogeneous fluorescence-based assays are susceptible to autofluorescence originating from biological material. This background autofluorescence can be eliminated by using upconverting phosphors (UCPs) that emit visible light upon excitation at near-infrared. In the assay energy was transferred from a UCP-donor to a conventional fluorophore acceptor that resided at one end of a caspase-3-specific substrate peptide. Attached to the other end was a quencher molecule that was used to attenuate the acceptor emission through intramolecular energy transfer in an intact peptide. In non-inhibitory conditions the enzyme reaction separated the fluorophore from the quencher and the emission of the fluorophore was recovered. The method was applied for the detection and characterization of a known caspase-3 inhibitor Z-DEVD-FMK, and the assay gave IC{sub 50} values of approximately 13 nM for this inhibitor. We have demonstrated the applicability of UCPs on a fluorescence-quenching-based homogeneous enzyme-activity assay for the detection of caspase-3 inhibitors. The use of near-infrared excitable UCPs enables inexpensive instrumentation and total elimination of autofluorescence, while the use of an

  11. Polychromatic spectral pattern analysis of ultra-weak photon emissions from a human body.

    Science.gov (United States)

    Kobayashi, Masaki; Iwasa, Torai; Tada, Mika

    2016-06-01

    Ultra-weak photon emission (UPE), often designated as biophoton emission, is generally observed in a wide range of living organisms, including human beings. This phenomenon is closely associated with reactive oxygen species (ROS) generated during normal metabolic processes and pathological states induced by oxidative stress. Application of UPE extracting the pathophysiological information has long been anticipated because of its potential non-invasiveness, facilitating its diagnostic use. Nevertheless, its weak intensity and UPE mechanism complexity hinder its use for practical applications. Spectroscopy is crucially important for UPE analysis. However, filter-type spectroscopy technique, used as a conventional method for UPE analysis, intrinsically limits its performance because of its monochromatic scheme. To overcome the shortcomings of conventional methods, the authors developed a polychromatic spectroscopy system for UPE spectral pattern analysis. It is based on a highly efficient lens systems and a transmission-type diffraction grating with a highly sensitive, cooled, charge-coupled-device (CCD) camera. Spectral pattern analysis of the human body was done for a fingertip using the developed system. The UPE spectrum covers the spectral range of 450-750nm, with a dominant emission region of 570-670nm. The primary peak is located in the 600-650nm region. Furthermore, application of UPE source exploration was demonstrated with the chemiluminescence spectrum of melanin and coexistence with oxidized linoleic acid. PMID:27082276

  12. RADSAT Benchmarks for Prompt Gamma Neutron Activation Analysis Measurements

    Energy Technology Data Exchange (ETDEWEB)

    Burns, Kimberly A.; Gesh, Christopher J.

    2011-07-01

    The accurate and efficient simulation of coupled neutron-photon problems is necessary for several important radiation detection applications. Examples include the detection of nuclear threats concealed in cargo containers and prompt gamma neutron activation analysis for nondestructive determination of elemental composition of unknown samples. High-resolution gamma-ray spectrometers are used in these applications to measure the spectrum of the emitted photon flux, which consists of both continuum and characteristic gamma rays with discrete energies. Monte Carlo transport is the most commonly used simulation tool for this type of problem, but computational times can be prohibitively long. This work explores the use of multi-group deterministic methods for the simulation of coupled neutron-photon problems. The main purpose of this work is to benchmark several problems modeled with RADSAT and MCNP to experimental data. Additionally, the cross section libraries for RADSAT are updated to include ENDF/B-VII cross sections. Preliminary findings show promising results when compared to MCNP and experimental data, but also areas where additional inquiry and testing are needed. The potential benefits and shortcomings of the multi-group-based approach are discussed in terms of accuracy and computational efficiency.

  13. A Raman cell based on hollow core photonic crystal fiber for human breath analysis

    Energy Technology Data Exchange (ETDEWEB)

    Chow, Kam Kong; Zeng, Haishan, E-mail: hzeng@bccrc.ca [Imaging Unit – Integrative Oncology Department, British Columbia Cancer Agency Research Centre, 675 West 10th Avenue, Vancouver, British Columbia V5Z 1L3, Canada and Medical Physics Program – Department of Physics and Astronomy, University of British Columbia, 6224 Agricultural Road, Vancouver, British Columbia V6T 1Z1 (Canada); Short, Michael; Lam, Stephen; McWilliams, Annette [Imaging Unit – Integrative Oncology Department, British Columbia Cancer Agency Research Centre, 675 West 10th Avenue, Vancouver, British Columbia V5Z 1L3 (Canada)

    2014-09-15

    Purpose: Breath analysis has a potential prospect to benefit the medical field based on its perceived advantages to become a point-of-care, easy to use, and cost-effective technology. Early studies done by mass spectrometry show that volatile organic compounds from human breath can represent certain disease states of our bodies, such as lung cancer, and revealed the potential of breath analysis. But mass spectrometry is costly and has slow-turnaround time. The authors’ goal is to develop a more portable and cost effective device based on Raman spectroscopy and hollow core-photonic crystal fiber (HC-PCF) for breath analysis. Methods: Raman scattering is a photon-molecular interaction based on the kinetic modes of an analyte which offers unique fingerprint type signals that allow molecular identification. HC-PCF is a novel light guide which allows light to be confined in a hollow core and it can be filled with a gaseous sample. Raman signals generated by the gaseous sample (i.e., human breath) can be guided and collected effectively for spectral analysis. Results: A Raman-cell based on HC-PCF in the near infrared wavelength range was developed and tested in a single pass forward-scattering mode for different gaseous samples. Raman spectra were obtained successfully from reference gases (hydrogen, oxygen, carbon dioxide gases), ambient air, and a human breath sample. The calculated minimum detectable concentration of this system was ∼15 parts per million by volume, determined by measuring the carbon dioxide concentration in ambient air via the characteristic Raman peaks at 1286 and 1388 cm{sup −1}. Conclusions: The results of this study were compared to a previous study using HC-PCF to trap industrial gases and backward-scatter 514.5 nm light from them. The authors found that the method presented in this paper has an advantage to enhance the signal-to-noise ratio (SNR). This SNR advantage, coupled with the better transmission of HC-PCF in the near-IR than in the

  14. A Raman cell based on hollow core photonic crystal fiber for human breath analysis

    International Nuclear Information System (INIS)

    Purpose: Breath analysis has a potential prospect to benefit the medical field based on its perceived advantages to become a point-of-care, easy to use, and cost-effective technology. Early studies done by mass spectrometry show that volatile organic compounds from human breath can represent certain disease states of our bodies, such as lung cancer, and revealed the potential of breath analysis. But mass spectrometry is costly and has slow-turnaround time. The authors’ goal is to develop a more portable and cost effective device based on Raman spectroscopy and hollow core-photonic crystal fiber (HC-PCF) for breath analysis. Methods: Raman scattering is a photon-molecular interaction based on the kinetic modes of an analyte which offers unique fingerprint type signals that allow molecular identification. HC-PCF is a novel light guide which allows light to be confined in a hollow core and it can be filled with a gaseous sample. Raman signals generated by the gaseous sample (i.e., human breath) can be guided and collected effectively for spectral analysis. Results: A Raman-cell based on HC-PCF in the near infrared wavelength range was developed and tested in a single pass forward-scattering mode for different gaseous samples. Raman spectra were obtained successfully from reference gases (hydrogen, oxygen, carbon dioxide gases), ambient air, and a human breath sample. The calculated minimum detectable concentration of this system was ∼15 parts per million by volume, determined by measuring the carbon dioxide concentration in ambient air via the characteristic Raman peaks at 1286 and 1388 cm−1. Conclusions: The results of this study were compared to a previous study using HC-PCF to trap industrial gases and backward-scatter 514.5 nm light from them. The authors found that the method presented in this paper has an advantage to enhance the signal-to-noise ratio (SNR). This SNR advantage, coupled with the better transmission of HC-PCF in the near-IR than in the

  15. Photon-photon collisions

    International Nuclear Information System (INIS)

    Highlights of the VIIIth International Workshop on Photon-Photon Collisions are reviewed. New experimental and theoretical results were reported in virtually every area of γγ physics, particularly in exotic resonance production and tests of quantum chromodynamics where asymptotic freedom and factorization theorems provide predictions for both inclusive and exclusive γγ reactions at high momentum transfer. 73 refs., 12 figs

  16. Photon-photon colliders

    Energy Technology Data Exchange (ETDEWEB)

    Sessler, Andrew M.

    1996-01-01

    Since the seminal work by Ginsburg, et al., the subject of giving the Next Linear Collider photon-photon capability, as well as electron-positron capability, has drawn much attention [1]. A 1990 article by V.I. Telnov describes the situation at that time [2]. In March 1994, the first workshop on this subject was held [3]. This report briefly reviews the physics that can be achieved through the photon-photon channel and then focuses on the means of achieving such a collider. Also reviewed is the spectrum of backscattered Compton photons—the best way of obtaining photons. We emphasize the spectrum actually obtained in a collider with both polarized electrons and photons (peaked at high energy and very different from a Compton spectrum). Luminosity is estimated for the presently considered colliders, and interaction and conversion-point geometries are described. Also specified are laser requirements (such as wavelength, peak power, and average power) and the lasers that might be employed. These include conventional and free-electron lasers. Finally, we describe the R&D necessary to make either of these approaches viable and explore the use of the SLC as a test bed for a photon-photon collider of very high energy.

  17. Broadband photon time of flight spectroscopy: advanced spectroscopic analysis for ensuring safety and performance of pharmaceutical tablets

    DEFF Research Database (Denmark)

    Kamran, Faisal; Nielsen, Otto Højager Attermann; Andersson-Engels, Stefan;

    2013-01-01

    We report on extended spectroscopic analysis of pharmaceutical tablets performed with broadband photon time-of-flight absorption/scaring spectroscopy. Precise monitoring of absorption and scattering spectra enables cost-efficient monitoring of key safety and performance parameters of the drugs....

  18. Analysis of photonic crystal and multi-frequency terahertz microstrip patch antenna

    International Nuclear Information System (INIS)

    In this paper, two-dimensional photonic crystals working at terahertz (THz) frequency is analyzed, a multi-frequency terahertz microstrip patch antenna on photonic crystal substrate is presented and its electromagnetic wave propagation phenomenon is investigated. The proposed antenna can work at five frequency points' scope at terahertz frequency regions, and the radiation efficiency is as high as ∼96%. The photonic crystal structure of the substrate is used to enhance the gain, directivity and radiation efficiency of the antenna

  19. Computational methods for the analysis and design of photonic bandgap structures

    OpenAIRE

    Qiu, Min

    2000-01-01

    In the present thesis, computational methods for theanalysis and design of photonic bandgap structure areconsidered. Many numerical methods have been used to study suchstructures. Among them, the plane wave expansion method is veryoften used. Using this method, we show that inclusions ofelliptic air holes can be used effectively to obtain a largercomplete band gap for two-dimensional (2D) photonic crystals.An optimal design of a 2D photonic crystal is also consideredin the thesis using a comb...

  20. Analysis of photonic crystal and multi-frequency terahertz microstrip patch antenna

    Energy Technology Data Exchange (ETDEWEB)

    Yang, Lechen, E-mail: yanglechen@163.com [The 41st Research Institute of CETC, Qingdao 266555, Shandong Province (China); Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, Jiangsu Province (China); Key Laboratory of Nanodevices and Applications, Chinese Academy of Science, Suzhou 215123, Jiangsu Province (China); Shi, Xueshun [The 41st Research Institute of CETC, Qingdao 266555, Shandong Province (China); Science and Technology on Electronic Test and Measurement Laboratory, Qingdao 266555, Shandong Province (China); Chen, Kunfeng [The 41st Research Institute of CETC, Qingdao 266555, Shandong Province (China); Fu, Kai; Zhang, Baoshun [Suzhou Institute of Nano-Tech and Nano-Bionics, Chinese Academy of Sciences, Suzhou 215123, Jiangsu Province (China); Key Laboratory of Nanodevices and Applications, Chinese Academy of Science, Suzhou 215123, Jiangsu Province (China)

    2013-12-15

    In this paper, two-dimensional photonic crystals working at terahertz (THz) frequency is analyzed, a multi-frequency terahertz microstrip patch antenna on photonic crystal substrate is presented and its electromagnetic wave propagation phenomenon is investigated. The proposed antenna can work at five frequency points' scope at terahertz frequency regions, and the radiation efficiency is as high as ∼96%. The photonic crystal structure of the substrate is used to enhance the gain, directivity and radiation efficiency of the antenna.

  1. The statistical fluctuation analysis for the measurement-device-independent quantum key distribution with heralded single-photon sources

    Science.gov (United States)

    Zhou, Xing-Yu; Zhang, Chun-Hui; Guo, Guang-Can; Wang, Qin

    2016-06-01

    In this paper, we carry out statistical fluctuation analysis for the new proposed measurement-device-independent quantum key distribution with heralded single-photon sources and further compare its performance with the mostly often used light sources, i.e., the weak coherent source. Due to a significantly lower probability for events with two photons present on the same side of the beam splitter in former than in latter, it gives drastically reduced quantum bit error rate in the X basis and can thus show splendid behavior in real-life implementations even when taking statistical fluctuations into account.

  2. Design and analysis of polarization independent all-optical logic gates in silicon-on-insulator photonic crystal

    Science.gov (United States)

    Rani, Preeti; Kalra, Yogita; Sinha, R. K.

    2016-09-01

    In this paper, we have reported design and analysis of polarization independent all optical logic gates in silicon-on-insulator photonic crystal consisting of two dimensional honeycomb lattices with two different air holes exhibiting photonic band gap for both TE and TM mode in the optical communication window. The proposed structures perform as an AND optical logic gate and all the optical logic gates based on the phenomenon of interference. The response period and bit rate for TE and TM polarizations at a wavelength of 1.55 μm show improved results as reported earlier.

  3. Complete nondestructive analysis of two-photon six-qubit hyperentangled Bell states assisted by cross-Kerr nonlinearity

    Science.gov (United States)

    Liu, Qian; Wang, Guan-Yu; Ai, Qing; Zhang, Mei; Deng, Fu-Guo

    2016-01-01

    Hyperentanglement, the entanglement in several degrees of freedom (DOFs) of a quantum system, has attracted much attention as it can be used to increase both the channel capacity of quantum communication and its security largely. Here, we present the first scheme to completely distinguish the hyperentangled Bell states of two-photon systems in three DOFs with the help of cross-Kerr nonlinearity without destruction, including two longitudinal momentum DOFs and the polarization DOF. We use cross-Kerr nonlinearity to construct quantum nondemolition detectors which can be used to make a parity-check measurement and analyze Bell states of two-photon systems in different DOFs. Our complete scheme for two-photon six-qubit hyperentangled Bell-state analysis may be useful for the practical applications in quantum information, especially in long-distance high-capacity quantum communication. PMID:26912172

  4. Complete nondestructive analysis of two-photon six-qubit hyperentangled Bell states assisted by cross-Kerr nonlinearity

    Science.gov (United States)

    Liu, Qian; Wang, Guan-Yu; Ai, Qing; Zhang, Mei; Deng, Fu-Guo

    2016-02-01

    Hyperentanglement, the entanglement in several degrees of freedom (DOFs) of a quantum system, has attracted much attention as it can be used to increase both the channel capacity of quantum communication and its security largely. Here, we present the first scheme to completely distinguish the hyperentangled Bell states of two-photon systems in three DOFs with the help of cross-Kerr nonlinearity without destruction, including two longitudinal momentum DOFs and the polarization DOF. We use cross-Kerr nonlinearity to construct quantum nondemolition detectors which can be used to make a parity-check measurement and analyze Bell states of two-photon systems in different DOFs. Our complete scheme for two-photon six-qubit hyperentangled Bell-state analysis may be useful for the practical applications in quantum information, especially in long-distance high-capacity quantum communication.

  5. Complete nondestructive analysis of two-photon six-qubit hyperentangled Bell states assisted by cross-Kerr nonlinearity.

    Science.gov (United States)

    Liu, Qian; Wang, Guan-Yu; Ai, Qing; Zhang, Mei; Deng, Fu-Guo

    2016-01-01

    Hyperentanglement, the entanglement in several degrees of freedom (DOFs) of a quantum system, has attracted much attention as it can be used to increase both the channel capacity of quantum communication and its security largely. Here, we present the first scheme to completely distinguish the hyperentangled Bell states of two-photon systems in three DOFs with the help of cross-Kerr nonlinearity without destruction, including two longitudinal momentum DOFs and the polarization DOF. We use cross-Kerr nonlinearity to construct quantum nondemolition detectors which can be used to make a parity-check measurement and analyze Bell states of two-photon systems in different DOFs. Our complete scheme for two-photon six-qubit hyperentangled Bell-state analysis may be useful for the practical applications in quantum information, especially in long-distance high-capacity quantum communication. PMID:26912172

  6. A Three-Photon Active Organic Fluorophore for Deep Tissue Ratiometric Imaging of Intracellular Divalent Zinc.

    Science.gov (United States)

    Philips, Divya Susan; Sreejith, Sivaramapanicker; He, Tingchao; Menon, Nishanth Venugopal; Anees, Palapuravan; Mathew, Jomon; Sajikumar, Sreedharan; Kang, Yuejun; Stuparu, Mihaiela Corina; Sun, Handong; Zhao, Yanli; Ajayaghosh, Ayyappanpillai

    2016-05-20

    Deep tissue bioimaging with three-photon (3P) excitation using near-infrared (NIR) light in the second IR window (1.0-1.4 μm) could provide high resolution images with an improved signal-to-noise ratio. Herein, we report a photostable and nontoxic 3P excitable donor-π-acceptor system (GMP) having 3P cross-section (σ3 ) of 1.78×10(-80)  cm(6)  s(2)  photon(-2) and action cross-section (σ3 η3 ) of 2.31×10(-81)  cm(6)  s(2)  photon(-2) , which provides ratiometric fluorescence response with divalent zinc ions in aqueous conditions. The probe signals the Zn(2+) binding at 530 and 600 nm, respectively, upon 1150 nm excitation with enhanced σ3 of 1.85×10(-80)  cm(6)  s(2)  photon(-2) and σ3 η3 of 3.33×10(-81)  cm(6)  s(2)  photon(-2) . The application of this probe is demonstrated for ratiometric 3P imaging of Zn(2+) in vitro using HuH-7 cell lines. Furthermore, the Zn(2+) concentration in rat hippocampal slices was imaged at 1150 nm excitation after incubation with GMP, illustrating its potential as a 3P ratiometric probe for deep tissue Zn(2+) ion imaging. PMID:26991763

  7. Elemental Analysis of Nanomaterial Using Photon-Atom Interaction Based EDXRF Technique

    Directory of Open Access Journals (Sweden)

    Sanjeev Kumar

    2013-08-01

    Full Text Available Presence of trace amount of foreign impurities (both metallic and non-metallic in standard salts used for sample preparation and during the synthesis process can alter the physical and chemical behavior of the pure and doped nano-materials. Therefore, it becomes important to determine concentration of various elements present in synthesized nano-material sample. In present work, the elemental and compositional analysis of nano-materials synthesized using various methods has been performed using photon-atom interaction based energy dispersive x-ray fluorescence (EDXRF technique. This technique due to its multielement analytical capability, lower detection limit, capability to analyze metals and non-metals alike and almost no sample preparation requirements can be utilized for analysis of nano-materials. The EDXRF spectrometer involves a 2.4 kW Mo anode x-ray tube (Pananalytic, Netherland equipped with selective absorbers as an excitation source and an LEGe detector (FWHM = 150 eV at 5.895 keV, Canberra, US coupled with PC based multichannel analyzer used to collect the fluorescentx-ray spectra. The analytical results showed good agreements with the expected values calculated on the basis of the precursor used in preparation of nano-materials.

  8. Segmentation, Reconstruction, and Analysis of Blood Thrombus Formation in 3D 2-Photon Microscopy Images

    Directory of Open Access Journals (Sweden)

    Xu Zhiliang

    2010-01-01

    Full Text Available We study the problem of segmenting, reconstructing, and analyzing the structure growth of thrombi (clots in blood vessels in vivo based on 2-photon microscopic image data. First, we develop an algorithm for segmenting clots in 3D microscopic images based on density-based clustering and methods for dealing with imaging artifacts. Next, we apply the union-of-balls (or alpha-shape algorithm to reconstruct the boundary of clots in 3D. Finally, we perform experimental studies and analysis on the reconstructed clots and obtain quantitative data of thrombus growth and structures. We conduct experiments on laser-induced injuries in vessels of two types of mice (the wild type and the type with low levels of coagulation factor VII and analyze and compare the developing clot structures based on their reconstructed clots from image data. The results we obtain are of biomedical significance. Our quantitative analysis of the clot composition leads to better understanding of the thrombus development, and is valuable to the modeling and verification of computational simulation of thrombogenesis.

  9. In vivo imaging of activated microglia in a mouse model of focal cerebral ischemia by two-photon microscopy.

    Science.gov (United States)

    Bok, Seoyeon; Wang, Taejun; Lee, Chan-Ju; Jeon, Seong-Uk; Kim, Young-Eun; Kim, Jeongwoo; Hong, Beom-Ju; Yoon, Calvin Jinse; Kim, Sungjee; Lee, Seung-Hoon; Kim, Hak Jae; Kim, Il Han; Kim, Ki Hean; Ahn, G-One

    2015-09-01

    Microglia are brain resident macrophages rapidly responding to various stimuli to exert appropriate inflammatory responses. Although they have recently been exploited as an attractive candidate for imaging neuroinflammation, it is still difficult to visualize them at the cellular and molecular levels. Here we imaged activated microglia by establishing intracranial window chamber (ICW) in a mouse model of focal cerebral ischemia by using two-photon microscopy (TPM), in vivo. Intravenous injection of fluorescent antibodies allowed us to detect significantly elevated levels of Iba-1 and CD68 positive activated microglia in the ipsilateral compared to the contralateral side of the infarct. We further observed that indomethacin, a non-steroidal anti-inflammatory drug significantly attenuated CD68-positive microglial activation in ICW, which was further confirmed by qRT-PCR biochemical analyses. In conclusion, we believe that in vivo TPM imaging of ICW would be a useful tool to screen for therapeutic interventions lowering microglial activation hence neuroinflammation. PMID:26417502

  10. Photon track evolution

    International Nuclear Information System (INIS)

    Given the time scale of biological, biochemical, biophysical and physical effects in a radiation exposure of living tissue, the first physical stage can be considered to be independent of time. All the physical interactions caused by the incident photons happen at the same starting time. From this point of view it would seem that the evolution of photon tracks is not a relevant topic for analysis; however, if the photon track is considered as a sequence of several interactions, there are several steps until the total degradation of the energy of the primary photon. We can characterise the photon track structure by the probability p(E,j), that is, the probability that a photon with energy E suffers j secondary interactions. The aim of this work is to analyse the photon track structure by considering j as a step of the photon track evolution towards the total degradation of the photon energy. Low energy photons (<150 keV) are considered, with water phantoms and half-extended geometry. The photon track evolution concept is presented and compared with the energy deposition along the track and also with the spatial distribution of the several steps in the photon track. (authors)

  11. Demonstration of active feedforward one-way quantum computing with photon-matter hyperentanglement

    OpenAIRE

    Xu, Xiao-Fan; Bao, Xiao-Hui; Pan, Jian-Wei

    2012-01-01

    We report an optical one-way quantum computing experiment with stationary quantum memory involved. First we create a hybrid four-qubit cluster state with two qubits propagating as photons and the other two stationary and stored in a laser-cooled atomic-ensemble quantum memory, and characterize it with entanglement witness and quantum state tomography. Then, by making use of this cluster state and fast operations of electro-optic modulators, we realize memory-assisted feedforward operations an...

  12. Reusable molecular sensor based on photonic activation control of DNA probes

    OpenAIRE

    Nishimura, Takahiro; Ogura, Yusuke; Tanida, Jun

    2012-01-01

    We propose a photoactivatable and resettable molecular sensor using DNA probes. The functionality is achieved by reversible change of DNA structure induced via photonic signals. Based on the mechanism, the sensor can detect target molecules at a desired instant and can be returned to its initial state after detection. The experimental results demonstrate that the concentrations of the target molecules are detected correctly and repeatedly according to the light signal.

  13. On the photonic cellular interaction and the electric activity of neurons in the human brain

    OpenAIRE

    Salari, V.; Tuszynski, J. A.; Bokkon, I.; Rahnama, M; Cifra, M.

    2011-01-01

    The subject of Ultraweak Photon Emission (UPE) by biological systems is very fascinating, and both evidence of its effects and applications are growing rapidly due to improvements in experimental techniques. Since the relevant equipment should be ultrasensitive with high quantum efficiencies and very low noise levels, the subject of UPE is still hotly debated and some of the interpretations need stronger empirical evidence to be accepted at face value. In this paper we first review different ...

  14. Photons to axion-like particles conversion in Active Galactic Nuclei

    Directory of Open Access Journals (Sweden)

    Fabrizio Tavecchio

    2015-05-01

    Full Text Available The idea that photons can convert to axion-like particles (ALPs γ→a in or around an AGN and reconvert back to photons a→γ in the Milky Way magnetic field has been put forward in 2008 and has recently attracted growing interest. Yet, so far nobody has estimated the conversion probability γ→a as carefully as allowed by present-day knowledge. Our aim is to fill this gap. We first remark that AGN which can be detected above 100 GeV are blazars, namely AGN with jets, with one of them pointing towards us. Moreover, blazars fall into two well defined classes: BL Lac objects (BL Lacs and Flat Spectrum Radio Quasars (FSRQs, with drastically different properties. In this Letter we report a preliminary evaluation of the γ→a conversion probability inside these two classes of blazars. Our findings are surprising. Indeed, while in the case of BL Lacs the conversion probability turns out to be totally unpredictable due to the strong dependence on the values of the somewhat uncertain position of the emission region along the jet and strength of the magnetic field therein, for FSRQs we are able to make a clear-cut prediction. Our results are of paramount importance in view of the planned very-high-energy photon detectors like the CTA, HAWK, GAMMA-400 and HISCORE.

  15. Complete hyperentangled-Bell-state analysis for photonic qubits assisted by a three-level Λ-type system

    Science.gov (United States)

    Wang, Tie-Jun; Wang, Chuan

    2016-01-01

    Hyperentangled Bell-state analysis (HBSA) is an essential method in high-capacity quantum communication and quantum information processing. Here by replacing the two-qubit controlled-phase gate with the two-qubit SWAP gate, we propose a scheme to distinguish the 16 hyperentangled Bell states completely in both the polarization and the spatial-mode degrees of freedom (DOFs) of two-photon systems. The proposed scheme reduces the use of two-qubit interaction which is fragile and cumbersome, and only one auxiliary particle is required. Meanwhile, it reduces the requirement for initializing the auxiliary particle which works as a temporary quantum memory, and does not have to be actively controlled or measured. Moreover, the state of the auxiliary particle remains unchanged after the HBSA operation, and within the coherence time, the auxiliary particle can be repeatedly used in the next HBSA operation. Therefore, the engineering complexity of our HBSA operation is greatly simplified. Finally, we discuss the feasibility of our scheme with current technologies.

  16. Analysis of Sunspot Activity Cycles

    Science.gov (United States)

    Greenkorn, Robert A.

    2009-04-01

    A nonlinear analysis of the daily sunspot number for each of cycles 10 to 23 is used to indicate whether the convective turbulence is stochastic or chaotic. There is a short review of recent papers considering sunspot statistics and solar activity cycles. The differences in the three possible regimes - deterministic laminar flow, chaotic flow, and stochastic flow - are discussed. The length of data sets necessary to analyze the regimes is investigated. Chaos is described and a chronology of recent results that utilize chaos and fractals to analyze sunspot numbers follows. The parameters necessary to describe chaos - time lag, phase space, embedding dimension, local dimension, correlation dimension, and the Lyapunov exponents - are determined for the attractor for each cycle. Assuming the laminar regime is unlikely if chaos is not indicated in a cycle by the calculations, the regime must be stochastic. The sunspot numbers in each of cycles 10 to 19 indicate stochastic behavior. There is a transition from stochastic to chaotic behavior of the sunspot numbers in cycles 20, 21, 22, and 23. These changes in cycles 20 - 23 may indicate a change in the scale of turbulence in the convection zone that could result in a change in the convective heat transfer and a change in the size of the convection region for these four cycles.

  17. Neutron activation analysis in Bulgaria

    International Nuclear Information System (INIS)

    The development of instrumental neutron activation analysis (INAA) as a routine method started in 1960 with bringing into use of the experimental nuclear reactor 2 MW -IRT-2000. For the purposes of INAA the vertical channels were used. The neutron flux vary from 1 to 6x1012n/cm2s, with Cd ratio for gold of about 4,4. In one of the channels the neutron flux is additionally thermalised with grafite, in others - a pneumatic double-tube rabbit system is installed. One of the irradiation positions is equiped with 1 mm Cd shield constantly. With the pressure of the working gas (air) of 2 bar the transport time in one direction is 2,5 sec. Because of lack of special system for uniform irradiation an accuracy of 3% can be reached by use of iron monitors for long irradiations and copper monitors for use in the rabbit system. Two neutron generators are also working but the application of 14 MeV neutrons for INAA is still quite limited. The most developed are the applications of INAA in the fields of geology and paedology, medicine and biology, environment and pollution, archaeology, metallurgy, metrology and hydrology, criminology

  18. Investigating the jet activity accompanying the production at the LHC of a massive scalar particle decaying into photons

    CERN Document Server

    Fuks, Benjamin; Park, Seong Chan; Seo, Min-Seok

    2016-01-01

    We study the jet activity that accompanies the production by gluon fusion of a new physics scalar particle decaying into photons at the LHC. In the considered scenarios, both the production and decay mechanisms are governed by loop-induced interactions involving a heavy colored state. We show that the presence of large new physics contributions to the inclusive diphoton invariant-mass spectrum always implies a significant production rate of non-standard diphoton events containing extra hard jets. We investigate the existence of possible handles that could provide a way to obtain information on the underlying physics behind the scalar resonance, and this in a wide mass window.

  19. Photon wave function formalism for analysis of Mach-Zehnder interferometer and sum-frequency generation

    Science.gov (United States)

    Ritboon, Atirach; Daengngam, Chalongrat; Pengpan, Teparksorn

    2016-08-01

    Biakynicki-Birula introduced a photon wave function similar to the matter wave function that satisfies the Schrödinger equation. Its second quantization form can be applied to investigate nonlinear optics at nearly full quantum level. In this paper, we applied the photon wave function formalism to analyze both linear optical processes in the well-known Mach-Zehnder interferometer and nonlinear optical processes for sum-frequency generation in dispersive and lossless medium. Results by photon wave function formalism agree with the well-established Maxwell treatments and existing experimental verifications.

  20. Channel analysis for single photon underwater free space quantum key distribution.

    Science.gov (United States)

    Shi, Peng; Zhao, Shi-Cheng; Gu, Yong-Jian; Li, Wen-Dong

    2015-03-01

    We investigate the optical absorption and scattering properties of underwater media pertinent to our underwater free space quantum key distribution (QKD) channel model. With the vector radiative transfer theory and Monte Carlo method, we obtain the attenuation of photons, the fidelity of the scattered photons, the quantum bit error rate, and the sifted key generation rate of underwater quantum communication. It can be observed from our simulations that the most secure single photon underwater free space QKD is feasible in the clearest ocean water. PMID:26366645

  1. Regional cerebral blood flow analysis of vascular dementia by the single photon emission computed tomography

    International Nuclear Information System (INIS)

    In order to evaluate the relationship between the regional cerebral blood flow (CBF) and cerebrovascular dementia, eleven patients with vascular dementia and eight patients with non-demented infarction were studied and regional CBF were measured quantitatively with single photon emission computed tomography (SPECT) by using N-isopropyl-p-(I-123) iodoamphetamine. All cases were basal infarction and vascular dementia were diagnosed by less than 21.5 of the Hasegawa's dementia score and more than 7 of Hachinsk's ischemic score. The results of the present study were as follows: (1) Cerebrovascular dementia showed lower mean CBF value compared with non-demented group. (2) Regional CBF of bilateral frontal areas and affected basal ganglia were significantly reduced than occipital area in the dementia group. (3) A comparison of regional CBF and the Hasegawa's dementia score revealed a statistically significant correlation at the bilateral frontal areas in the dementia group. It is possible that measuring the regional CBF quantitatively by IMP-SPECT is useful for clinical analysis of vascular dementia. (author)

  2. Conference on instrumental activation analysis IAA 92

    International Nuclear Information System (INIS)

    The publication contains 26 abstracts primarily concerned with neutron activation analysis, although other analytical techniques based on X-ray fluorescence analysis, PIXE, PIGE, RBS are also included. Some contributions deal with aspects of quality practice and assurance in radioanalytical laboratories, with marketing of instrumental neutron activation analysis services, with hard- and software aspects of radiation detection, etc. (Z.S.)

  3. Activation of silicon quantum dots and coupling between the active centre and the defect state of the photonic crystal in a nanolaser

    International Nuclear Information System (INIS)

    A new nanolaser concept using silicon quantum dots (QDs) is proposed. The conduction band opened by the quantum confinement effect gives the pumping levels. Localized states in the gap due to some surface bonds on Si QDs can be formed for the activation of emission. An inversion of population can be generated between the localized states and the valence band in a QD fabricated by using a nanosecond pulse laser. Coupling between the active centres formed by localized states and the defect states of the two-dimensional (2D) photonic crystal can be used to select the model in the nanolaser. (electromagnetism, optics, acoustics, heat transfer, classical mechanics, and fluid dynamics)

  4. Generation and analysis of correlated pairs of photons on board a nanosatellite

    CERN Document Server

    Tang, Zhongkan; Tan, Yue Chuan; Cheng, Cliff; Sha, Luo; Hiang, Goh Cher; Oi, Daniel; Ling, Alexander

    2016-01-01

    Satellites carrying sources of entangled photons could establish a global quantum network, enabling private encryption keys between any two points on Earth. Despite numerous proposals, demonstration of space-based quantum systems has been limited due to the cost of traditional satellites. We are using very small spacecraft to accelerate progress. We report the in-orbit operation of a photon pair source aboard a 1.65 kg nanosatellite and demonstrate pair generation and polarization correlation under space conditions. The in-orbit photon correlations exhibit a contrast of 97+/-2%, matching ground-based tests. This pathfinding mission overcomes the challenge of demonstrating in-orbit performance for the components of future entangled photon experiments. Ongoing operation establishes the in-orbit lifetime of these critical components. More generally, this demonstrates the ability for nanosatellites to enable faster progress in space-based research.

  5. Analysis of Sampled Fiber Bragg Grating Based on the Photonic Crystal Theory

    Institute of Scientific and Technical Information of China (English)

    ZHU Dan-dan

    2009-01-01

    One of the most basic characteristics of photonic crystal is frequency band gap.When defects are introduced into the periodic photonic crystal,a number of defect modes appear in the stop band.In this paper,we exploit transfer matrix method based on photonic crystal theory,and assume the sampled fiber Bragg grating as one-dimensional dual photonic crystal with a large size defect.Characteristics of the sampled fiber Bragg grating are analyzed.Experimental results show that the sampled fiber Bragg grating has many reflective peaks.Its reflectivity,center wavelength,reflective peak intervals and band width all change with the grating parameters,including grating length,duty ratio of the material with high dielectric constant,and index modulation depth and period.Results agree with the conventional couple mode theory which can be used when analyzing other characteristics of the sampled fiber Bragg grating or applying it into practice.

  6. Photon-photon collisions

    Energy Technology Data Exchange (ETDEWEB)

    Brodsky, S.J.

    1985-01-01

    The study of photon-photon collisions has progressed enormously, stimulated by new data and new calculational tools for QCD. In the future we can expect precise determinations of ..cap alpha../sub s/ and ..lambda../sup ms/ from the ..gamma..*..gamma.. ..-->.. ..pi../sup 0/ form factor and the photon structure function, as well as detailed checks of QCD, determination of the shape of the hadron distribution amplitudes from ..gamma gamma.. ..-->.. H anti H, reconstruction of sigma/sub ..gamma gamma../ from exclusive channels at low W/sub ..gamma gamma../, definitive studies of high p/sub T/ hadron and jet production, and studies of threshold production of charmed systems. Photon-photon collisions, along with radiative decays of the psi and UPSILON, are ideal for the study of multiquark and gluonic resonances. We have emphasized the potential for resonance formation near threshold in virtually every hadronic exclusive channel, including heavy quark states c anti c c anti c, c anti c u anti u, etc. At higher energies SLC, LEP, ...) parity-violating electroweak effects and Higgs production due to equivalent Z/sup 0/ and W/sup + -/ beams from e ..-->.. eZ/sup 0/ and e ..-->.. nu W will become important. 44 references.

  7. Photon-photon collisions

    International Nuclear Information System (INIS)

    The current status, both theoretical and experimental, of two photon collision physics is reviewed with special emphasis on recent experimental results from e+e- storage rings. After a complete presentation of the helicity amplitude formalism for the general process e+e- → Xe+e-, various approximations (transverse photon, Weisaecker Williams) are discussed. Beam polarisation effects and radiative corrections are also briefly considered. A number of specific processes, for which experimental results are now available, are then described. In each case existing theoretical prediction are confronted with experimental results. The processes described include single resonance production, lepton and hadron pair production, the structure functions of the photon, the production of high Psub(T) jets and the total photon photon cross section. In the last part of the review the current status of the subject is summarised and some comments are made on future prospects. These include both extrapolations of current research to higher energy machines (LEP, HERA) as well as a brief mention of both the technical realisation and the physics interest of the real γγ and eγ collisions which may be possible using linear electron colliders in the 1 TeV energy range

  8. Optical spectral analysis of ultra-weak photon emission from tissue culture and yeast cells

    Czech Academy of Sciences Publication Activity Database

    Nerudová, Michaela; Červinková, Kateřina; Hašek, Jiří; Cifra, Michal

    Bellingham: SPIE, 2015, 94500O. ISBN 9781628415667. ISSN 0277-786X. [8th International Conference on Photonics, Devices, and System VI. Praha (CZ), 27.08.2014-29.08.2014] R&D Projects: GA ČR GA13-29294S Institutional support: RVO:67985882 ; RVO:61388971 Keywords : Ultra-weak photon emission * Optical spectrum * HL60 cells Subject RIV: BO - Biophysics; EE - Microbiology, Virology (MBU-M)

  9. Design and Analysis of Microstrip Multi-Channeled Filter Using Photonic Crystal Branchy Defect

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    A multi-channeled filter based on branchy defect in a microstrip photonic crystal was proposed. By introducing a branchy structure across the defect region, multiple defect modes will appear inside the photonic gap, leading to the multi-channeled filtering phenomenon. In comparison with the conventional multi-channeled filters, the proposed structure is more compact and tunable as far as the device volume and fabrication are concerned. The microwave experiment results are found in agreement with simulation results.

  10. The photon analysis, delivery, and reduction system at the FERMI-Elettra free electron laser user facility

    International Nuclear Information System (INIS)

    The FERMI-Elettra free electron laser (FEL) user facility is currently under construction at the Sincrotrone Trieste laboratory in Trieste (Italy). It will cover the wavelength range from 100 to about 5 nm in the fundamental and 3 or 1 nm using the third harmonic. We report the layout of the photon beam diagnostics section, the radiation transport system to the experimental area, and the photon beam distribution system. Due to the peculiar characteristics of the emitted FEL radiation (high peak power, short pulse length, and statistical variation of the emitted intensity and distribution), the realization of the diagnostics system is particularly challenging. The end users are interested in parameters such as the radiation pulse intensity and spectral distribution, as well as in the possibility to attenuate the intensity. In order to accomplish these tasks, a photon analysis, delivery, and reduction system is now under development and construction and is presented here. This system will work on-line producing pulse-resolved information and will let users keep track of the photon beam parameters during the experiments.

  11. Demonstration of active feedforward one-way quantum computing with photon-matter hyperentanglement

    Science.gov (United States)

    Xu, Xiao-Fan; Bao, Xiao-Hui; Pan, Jian-Wei

    2012-11-01

    We report an optical one-way quantum computing experiment with stationary quantum memory involved. First we create a hybrid four-qubit cluster state with two qubits propagating as photons and the other two stationary and stored in a laser-cooled atomic-ensemble quantum memory, and characterize it with entanglement witnesses and quantum state tomography. Then, by making use of this cluster state and fast operations of electro-optic modulators, we realize memory-assisted feedforward operations and demonstrate deterministic single-qubit rotation as an example.

  12. Instrumental neutron activation analysis - a routine method

    International Nuclear Information System (INIS)

    This thesis describes the way in which at IRI instrumental neutron activation analysis (INAA) has been developed into an automated system for routine analysis. The basis of this work are 20 publications describing the development of INAA since 1968. (Auth.)

  13. Theoretical Analysis of a Vertical Channel Dropping Tunnelling Process in a Photonic Crystal for Wavelength Division Demultiplexing

    Institute of Scientific and Technical Information of China (English)

    符建; 何赛灵; 肖三水; 仇霪; 何建军

    2001-01-01

    A theoretical analysis is presented for a channel drop tunnelling structure composed of a horizontal input channel, a vertical output channel and a multi-mode cavity in a photonic crystal. Criteria for a complete transfer are derived for applications of wavelength division demultiplexing. The analytical results are verified with a numerical simulation using a finite difference time domain method. The vertical channel dropping tunnelling system makes the demultiplexing device much more compact, as compared to the conventional parallel channel dropping system.

  14. On the Partial-Wave Analysis of Mesonic Resonances Decaying to Multiparticle Final States Produced by Polarized Photons

    Energy Technology Data Exchange (ETDEWEB)

    Salgado, Carlos W. [Norfolk State University, Norfolk, VA (United States) and Thomas Jefferson National Accelerator Facility, Newport News, VA (United States); Weygand, Dennis P. [Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)

    2014-04-01

    Meson spectroscopy is going through a revival with the advent of high statistics experiments and new advances in the theoretical predictions. The Constituent Quark Model (CQM) is finally being expanded considering more basic principles of field theory and using discrete calculations of Quantum Chromodynamics (lattice QCD). These new calculations are approaching predictive power for the spectrum of hadronic resonances and decay modes. It will be the task of the new experiments to extract the meson spectrum from the data and compare with those predictions. The goal of this report is to describe one particular technique for extracting resonance information from multiparticle final states. The technique described here, partial wave analysis based on the helicity formalism, has been used at Brookhaven National Laboratory (BNL) using pion beams, and Jefferson Laboratory (Jlab) using photon beams. In particular this report broaden this technique to include production experiments using linearly polarized real photons or quasi-real photons. This article is of a didactical nature. We describe the process of analysis, detailing assumptions and formalisms, and is directed towards people interested in starting partial wave analysis.

  15. On the partial-wave analysis of mesonic resonances decaying to multiparticle final states produced by polarized photons

    Energy Technology Data Exchange (ETDEWEB)

    Salgado, Carlos W., E-mail: salgado@jlab.org [Norfolk State University (United States); The Thomas Jefferson National Accelerator Facility (United States); Weygand, Dennis P. [The Thomas Jefferson National Accelerator Facility (United States)

    2014-04-01

    Meson spectroscopy is going through a revival with the advent of high statistics experiments and new advances in the theoretical predictions. The Constituent Quark Model (CQM) is finally being expanded considering more basic principles of field theory and using discrete calculations of Quantum Chromodynamics (lattice QCD). These new calculations are approaching predictive power for the spectrum of hadronic resonances and decay modes. It will be the task of the new experiments to extract the meson spectrum from the data and compare with those predictions. The goal of this report is to describe one particular technique for extracting resonance information from multiparticle final states. The technique described here, partial wave analysis based on the helicity formalism, has been used at Brookhaven National Laboratory (BNL) using pion beams, and Jefferson Laboratory (JLab) using photon beams. In particular this report broadens this technique to include production experiments using linearly polarized real photons or quasi-real photons. This article is of a didactical nature. We describe the process of analysis, detailing assumptions and formalisms, and is directed towards people interested in starting partial wave analysis.

  16. Photons into axion-like particles conversion in Active Galactic Nuclei

    CERN Document Server

    Tavecchio, Fabrizio; Galanti, Giorgio

    2014-01-01

    The idea that photons can convert into axion-like particles (ALPs) $\\gamma \\to a$ in or around an AGN and reconvert back into photons $a \\to \\gamma$ in the Milky Way magnetic field has been put forward in 2008 and has recently attracted growing interest. Yet, so far nobody has estimated the conversion probability $\\gamma \\to a$ as carefully as allowed by present-day knowledge. Our aim is to fill this gap. We first remark that AGN that can be detected above 100 GeV are blazars, namely AGN with jets, with one of them pointing towards us. Moreover, blazars fall into two well defined classes: BL Lac objects (BL Lacs) and Flat Spectrum Radio Quasars (FSRQs), with drastically different properties. In this Letter we evaluate the $\\gamma \\to a$ conversion probability inside these two classes of blazars, taking also the host elliptical galaxy into account. Our findings are surprising. For, while in the case of BL Lacs the conversion probability turns out to be totally unpredictable due to the strong dependence on the ...

  17. Computational Study and Analysis of Structural Imperfections in 1D and 2D Photonic Crystals

    Energy Technology Data Exchange (ETDEWEB)

    K.R. Maskaly

    2005-06-01

    Dielectric reflectors that are periodic in one or two dimensions, also known as 1D and 2D photonic crystals, have been widely studied for many potential applications due to the presence of wavelength-tunable photonic bandgaps. However, the unique optical behavior of photonic crystals is based on theoretical models of perfect analogues. Little is known about the practical effects of dielectric imperfections on their technologically useful optical properties. In order to address this issue, a finite-difference time-domain (FDTD) code is employed to study the effect of three specific dielectric imperfections in 1D and 2D photonic crystals. The first imperfection investigated is dielectric interfacial roughness in quarter-wave tuned 1D photonic crystals at normal incidence. This study reveals that the reflectivity of some roughened photonic crystal configurations can change up to 50% at the center of the bandgap for RMS roughness values around 20% of the characteristic periodicity of the crystal. However, this reflectivity change can be mitigated by increasing the index contrast and/or the number of bilayers in the crystal. In order to explain these results, the homogenization approximation, which is usually applied to single rough surfaces, is applied to the quarter-wave stacks. The results of the homogenization approximation match the FDTD results extremely well, suggesting that the main role of the roughness features is to grade the refractive index profile of the interfaces in the photonic crystal rather than diffusely scatter the incoming light. This result also implies that the amount of incoherent reflection from the roughened quarterwave stacks is extremely small. This is confirmed through direct extraction of the amount of incoherent power from the FDTD calculations. Further FDTD studies are done on the entire normal incidence bandgap of roughened 1D photonic crystals. These results reveal a narrowing and red-shifting of the normal incidence bandgap with

  18. Green silicon photonics

    OpenAIRE

    Jalali, B.; Fathpour, S.; Tsia, K

    2009-01-01

    Silicon photonics have provided low-cost communication components for Internet applications and are now aimed towards providing environmentally friendly and green optical solutions. The need for energy-efficient photonics is due to the excessive energy dissipated in advanced electronics and an increase in power density that has posed a challenge to the most advanced chip-cooling technologies. The two-photon absorption (TPA)-generated free carriers need to be actively removed from the waveguid...

  19. Heavy-ion elastic-recoil detection analysis of doped-silica films for integrated photonics

    International Nuclear Information System (INIS)

    Photosensitive silica films, in which a permanent refractive index change is induced by exposure to ultra-violet (UV) light, are of interest for the fabrication of integrated photonic devices and circuits. Such films, consisting of Ge- and Sn-doped silica, are being fabricated at the Australian National University (ANU) by a plasma assisted deposition technique known as Helicon Assisted Reactive Evaporation (HARE). The initial refractive index of these films is related to their stoichiometry and can be altered further by controlled exposure to UV light . Contaminants introduced into the films during deposition can degrade their optical properties and are therefore also of interest. Hydrogen is of particular concern as it causes optical absorption in the wavelength range of interest for communications applications (1.3-1.5μm). High-energy heavy ion elastic recoil detection (ERD) analysis enables the detection of a broad range of elements with almost constant sensitivity. A variety of recoil detection systems have been developed for this purpose, including time-of-flight systems, magnetic spectrometers, and quadrupole spectrometers. However, these are often restricted to small acceptance solid angles. Beam-induced sample modification, such as hydrogen release, can therefore be a serious limitation. The use of a position sensitive gas ionization detector overcomes these limitations for a range of import ant applications by operating with a large solid angle and correcting the kinematic energy spread of the ions over large acceptance angles to provide ≤1% energy resolution. In this study, heavy-ion ERD employing a novel position sensitive gas ionization detector is used to characterize the composition, thickness, uniformity and hydrogen content of Ge- and Sn- doped silica films. The technique is shown to provide this information in a single measurement

  20. Photonic crystals with plasmonic patterns: novel type of the heterostructures for enhanced magneto-optical activity

    International Nuclear Information System (INIS)

    A multilayer structure consisting of a magnetophotonic crystal with a rare-earth iron garnet microresonator layer and plasmonic grating deposited on it was fabricated and studied in order to combine functionalities of photonic and plasmonic crystals. The plasmonic pattern allows excitation of the hybrid plasmonic-waveguide modes localized in dielectric Bragg mirrors of the magnetophotonic crystal or waveguide modes inside its microresonator layer. These modes give rise to the additional resonances in the optical spectra of the structure and to the enhancement of the magneto-optical effects. The Faraday effect increases by about 50% at the microresonator modes while the transverse magneto-optical Kerr effect demonstrates pronounced peculiarities at both hybrid waveguide modes and microresonator modes and increases by several times with respect to the case of the bare magnetophotonic crystal without the metal grating. (paper)

  1. Transportation activity analysis using smartphones

    OpenAIRE

    Xiao, Yu; Low, David; Bandara, Thusitha; Pathak, Parth; Lim, Hock Beng; Goyal, Devendra; Santos, Jorge Oliveira; Cottrill, Caitlin; Pereira, Francisco C.; Zegras, P. Christopher; Ben-Akiva, Moshe E.

    2012-01-01

    Transportation activity surveys investigate when, where and how people travel in urban areas to provide information necessary for urban transportation planning. In Singapore, the Land Transport Authority (LTA) carries out such a survey amongst households every four years. The survey is conducted through conventional questionnaires and travel diaries. However, the conventional surveys are problematic and error-prone. We are developing a smartphone-based transportation activity survey system to...

  2. Activation analysis with reactor neutrons

    International Nuclear Information System (INIS)

    The potentialities of neutron as an analytical probe are indicated, pointing out the need for development of other approaches, besides the conventional activation method. Development of instrumental approach to activation and applications, carried out at Analytical Chemistry Division are outlined. The role of, and the need for, the development and application of mathematical methods in enhancing the information content, and in turn the interpretation of the analytical results, is demonstrated. (author)

  3. Background Noise Analysis in a Few-Photon-Level Qubit Memory

    Science.gov (United States)

    Mittiga, Thomas; Kupchak, Connor; Jordaan, Bertus; Namazi, Mehdi; Nolleke, Christian; Figeroa, Eden

    2014-05-01

    We have developed an Electromagnetically Induced Transparency based polarization qubit memory. The device is composed of a dual-rail probe field polarization setup colinear with an intense control field to store and retrieve any arbitrary polarization state by addressing a Λ-type energy level scheme in a 87Rb vapor cell. To achieve a signal-to-background ratio at the few photon level sufficient for polarization tomography of the retrieved state, the intense control field is filtered out through an etalon filtrating system. We have developed an analytical model predicting the influence of the signal-to-background ratio on the fidelities and compared it to experimental data. Experimentally measured global fidelities have been found to follow closely the theoretical prediction as signal-to-background decreases. These results suggest the plausibility of employing room temperature memories to store photonic qubits at the single photon level and for future applications in long distance quantum communication schemes.

  4. 2-Photon Characterization of Optical Proteolytic Beacons for Imaging Changes in Matrix-Metalloprotease Activity in a Mouse Model of Aneurysm

    Science.gov (United States)

    Haskett, Darren G.; Maestas, David; Howerton, Stephen J.; Smith, Tyler; Ardila, D. Catalina; Doetschman, Tom; Utzinger, Urs; McGrath, Dominic; McIntyre, J. Oliver; Vande Geest, Jonathan P.

    2016-01-01

    Abdominal aortic aneurysm is a multifactorial disease that is a leading cause of death in developed countries. Matrix-metalloproteases (MMPs) are part of the disease process, however, assessing their role in disease initiation and progression has been difficult and animal models have become essential. Combining Förster resonance energy transfer (FRET) proteolytic beacons activated in the presence of MMPs with 2-photon microscopy allows for a novel method of evaluating MMP activity within the extracellular matrix (ECM). Single and 2-photon spectra for proteolytic beacons were determined in vitro. Ex vivo experiments using the apolipoprotein E knockout angiotensin II-infused mouse model of aneurysm imaged ECM architecture simultaneously with the MMP-activated FRET beacons. 2-photon spectra of the two-color proteolytic beacons showed peaks for the individual fluorophores that enable imaging of MMP activity through proteolytic cleavage. Ex vivo imaging of the beacons within the ECM revealed both microstructure and MMP activity. 2-photon imaging of the beacons in aneurysmal tissue showed an increase in proteolytic cleavage within the ECM (p < 0.001), thus indicating an increase in MMP activity. Our data suggest that FRET-based proteolytic beacons show promise in assessing MMP activity within the ECM and will therefore allow future studies to identify the heterogeneous distribution of simultaneous ECM remodeling and protease activity in aneurysmal disease. PMID:26903264

  5. Neutron activation analysis of biological substances

    International Nuclear Information System (INIS)

    A Bowen cabbage sample was used as a reference material for the neutron activation studies, and the method was checked by the analysis of other biological substances (blood or serum etc.). For nondestructive measurements also some non-trace elements were determined in order to decide whether the activation analysis is a useful means for such measurements. The new activation analysis procedure was used for biomedical studies as, e.g., for trace element determination in body fluids, and for the analysis of inorganic components in air samples. (R.P.)

  6. Complete hyperentangled-Bell-state analysis for photon systems assisted by quantum-dot spins in optical microcavities.

    Science.gov (United States)

    Ren, Bao-Cang; Wei, Hai-Rui; Hua, Ming; Li, Tao; Deng, Fu-Guo

    2012-10-22

    Bell-state analysis (BSA) is essential in quantum communication, but it is impossible to distinguish unambiguously the four Bell states in the polarization degree of freedom (DOF) of two-photon systems with only linear optical elements, except for the case in which the BSA is assisted with hyperentangled states, the simultaneous entanglement in more than one DOF. Here, we propose a scheme to distinguish completely the 16 hyperentangled Bell states in both the polarization and the spatial-mode DOFs of two-photon systems, by using the giant nonlinear optics in quantum dot-cavity systems. This scheme can be applied to increase the channel capacity of long-distance quantum communication based on hyperentanglement, such as entanglement swapping, teleportation, and superdense coding. We use hyperentanglement swapping as an example to show the application of this HBSA. PMID:23187229

  7. On the Partial-Wave Analysis of Mesonic Resonances Decaying to Multiparticle Final States Produced by Polarized Photons

    CERN Document Server

    Salgado, Carlos W

    2013-01-01

    Meson spectroscopy is going through a revival with the advent of high statistics experiments and new advances in the theoretical predictions. The Constituent Quark Model (CQM) is finally being expanded considering more basic principles of field theory and using discrete calculations of Quantum Chromodynamics (lattice QCD). These new calculations are approaching predictive power for the spectrum of hadronic resonances and decay modes. It will be the task of the new experiments to extract the meson spectrum from the data and compare with those predictions. The goal of this report is to describe one particular technique for extracting resonance information from multiparticle final states. The technique described here, partial wave analysis based on the helicity formalism, has been used at Brookhaven National Laboratory (BNL) using pion beams, and Jefferson Laboratory (JLab) using photon beams. In particular this report broaden this technique to include production experiments using linearly polarized real photons...

  8. Theoretical analysis of a biased photonic crystal fiber infiltrated with a negative dielectric anisotropy liquid crystal

    DEFF Research Database (Denmark)

    Weirich, Johannes; Wei, Lei; Lægsgaard, Jesper;

    2009-01-01

    We simulate the PBG mode of a biased Photonic Crystal Fiber (PCF) infiltrated with a Liquid Crystal (LC) with negative dielectric anisotropy. We analyse the voltage induced change of the transmission spectrum, dispersion and losses and compare them to the experimental values.......We simulate the PBG mode of a biased Photonic Crystal Fiber (PCF) infiltrated with a Liquid Crystal (LC) with negative dielectric anisotropy. We analyse the voltage induced change of the transmission spectrum, dispersion and losses and compare them to the experimental values....

  9. Analysis of HR activities in selected company

    OpenAIRE

    Jandová, Šárka

    2012-01-01

    The aim of this thesis is based on theoretical knowledge and analysis of the basic HR activities in the selected company to identify the strengths and weaknesses of the policies implemented personnel work. Then propose an effective ways of improving HR activities and employee satisfaction. Basic personal activities analyzed in this thesis are the adaptation, acquisition and selection of employees, performance management and staff appraisal, remuneration and training of staff. Analysis of pers...

  10. Conference on instrumental activation analysis - IAA 89

    International Nuclear Information System (INIS)

    The proceedings contain 40 abstracts of papers all of which have been incorporated in INIS. The papers were centred on the applications of radioanalytical methods, especialy on neutron activation analysis, X-ray fluorescence analysis, PIXE analysis and tracer techniques in biology, medicine and metallurgy, measuring instruments including microcomputers, and data processing methods. (J.P.)

  11. Conference on Instrumental Activation Analysis: IAA 89

    Science.gov (United States)

    Vobecky, M.; Obrusnik, I.

    1989-05-01

    The proceedings contain 40 abstracts of papers all of which have been incorporated in INIS. The papers were centred on the applications of radioanalytical methods, especially on neutron activation analysis, x ray fluorescence analysis, PIXE analysis and tracer techniques in biology, medicine and metallurgy, measuring instruments including microcomputers, and data processing methods.

  12. A computational analysis of intrinsic detection efficiencies of Geiger-Mueller tubes for photons

    CERN Document Server

    Watanabe, T

    1999-01-01

    A new calculation of the intrinsic detection efficiency of the Geiger-Mueller tube (GM tube) for photons is presented. It is found by the calculation that the relation between the efficiency and incident photon energy depends on the cathode materials and thicknesses. For a bare GM tube with the lead cathode of 20 mm in inner diameter, the 0.1 mm thick cathode wall is sensitive in lower photon energies, while 1 mm thick one works sensitively in the higher energy region. On the other hand, the 0.2 mm tube has flat sensitivity over a wide energy region between 0.3 and 3 MeV. For the GM tubes with lead, tin, and copper cathodes whose wall thicknesses are selected as having flat sensitivity, while the efficiency decreases with decreasing atomic number of the wall metal, flat regions extend to lower photon energies. The detection efficiencies of GM tubes with a sheath or a probe (sheathed GM tube) are discussed.

  13. A computational analysis of intrinsic detection efficiencies of Geiger-Mueller tubes for photons

    International Nuclear Information System (INIS)

    A new calculation of the intrinsic detection efficiency of the Geiger-Mueller tube (GM tube) for photons is presented. It is found by the calculation that the relation between the efficiency and incident photon energy depends on the cathode materials and thicknesses. For a bare GM tube with the lead cathode of 20 mm in inner diameter, the 0.1 mm thick cathode wall is sensitive in lower photon energies, while 1 mm thick one works sensitively in the higher energy region. On the other hand, the 0.2 mm tube has flat sensitivity over a wide energy region between 0.3 and 3 MeV. For the GM tubes with lead, tin, and copper cathodes whose wall thicknesses are selected as having flat sensitivity, while the efficiency decreases with decreasing atomic number of the wall metal, flat regions extend to lower photon energies. The detection efficiencies of GM tubes with a sheath or a probe (sheathed GM tube) are discussed

  14. Ultrasmall-angle X-ray scattering analysis of photonic crystal structure

    NARCIS (Netherlands)

    Abramova, V.V.; Sinitskii, A.S.; Grigoryeva, N.A.; Grigoriev, S.V.; Belov, D.V.; Petukhov, A.V.; Mistonov, A.A.; Vasilieva, A.V.; Tretyakov, Y.D.

    2009-01-01

    The results of an ultrasmall angle X ray scattering study of iron(III) oxide inverse opal thin films are presented. The photonic crystals examined are shown to have fcc structure with amount of stacking faults varying among the samples. The method used in this study makes it possible to easily disti

  15. Radiation quality of photons in small and large receptors - A Micro-dosimetric analysis

    International Nuclear Information System (INIS)

    The quality of different photon radiations in small and large receptors is assessed in terms of Micro-dosimetry. Monte Carlo simulations are performed for the electrons released by photons. To represent the case of a small receptor, only electrons released by the non-degraded incident photons are tracked. For a large receptor, all electrons released in the complete degradation process are followed. Dose averaged values, yD, of the lineal energy are derived from the simulated tracks for monoenergetic photons from 10 keV to 2 MeV. In Micro-dosimetry, the dose mean lineal energy is the major parameter of radiation quality. The results demonstrate distinct differences in radiation quality between high-energy gamma rays and conventional X-rays that are present not just in small cell samples but also in large receptors, such as the human body. The values of yD suggest that, for both small and large receptors, conventional X-rays should be about twice as effective as gamma rays from 60Co. (authors)

  16. Multi-scale electrodynamics (MELD): a CAD tool for photonics analysis and design

    Energy Technology Data Exchange (ETDEWEB)

    Ratowsky, R.P.; Kallman, J.S.; Deri, R.J.; Pocha, M.D.

    1998-02-06

    In FY97 we completed work on the (MELD) code, a comprehensive, multiple-length-scale, Graphical User Interface (GUI)-driven photonics design tool. In 1997 MELD was rated one of the one hundred most technologically significant new products of the year by Research and Development magazine.

  17. Isomer Population Analysis of Gaseous Ions From Infrared Multiple Photon Dissociation Kinetics

    NARCIS (Netherlands)

    Prell, J. S.; Chang, T. M.; Biles, J. A.; G. Berden,; Oomens, J.; Williams, E. R.

    2011-01-01

    Infrared multiple photon dissociation (IRMPD) kinetics measured with tunable laser radiation from a free electron laser (FEL) are used to probe the relative populations of and interconversions between energetically competitive isomers of gas-phase ions at 298 K. On-resonance IRMPD kinetics of monois

  18. Neutron activation analysis of reference materials

    International Nuclear Information System (INIS)

    The importance is pointed out of neutron activation analysis in the preparation of reference materials, and studies are reported conducted recently by UJV. Instrumental neutron activation analysis has been used in testing homogeneity and in determining 28 elements in newly prepared reference standards of coal fly ash designated ENO, EOP and ECH. For accuracy testing, the same method was used in the analysis of NBS SRM-1633a Trace Elements in Coal Fly Ash and IAEA CRM Soil-5 and RM Soil-7. Radiochemical neutron activation analysis was used in determining Cd, Cu, Mn, Mo, and Zn in biological materials NBS SRM-1577 Bovine Liver, Bowen's Kale and in IAEA RM Milk Powder A-11 and Animal Muscle H-4. In all instances very good precision and accuracy of neutron activation analysis results were shown. (author)

  19. Effects of single-dose irradiation on tumor blood flow studied by 15O decay after photon activation in situ

    International Nuclear Information System (INIS)

    A noninvasive technique employing photon activation of tissue oxygen in situ and detection of subsequent 15O positron decay was used to study the effects of single-dose 60Co irradiation on capillary blood flow in transplanted rat rhabdomyosarcomas. Tumor blood flow was measured before irradiation with 16.5, 38.5, or 60.5 Gy and at sever al intervals afterward (0-72 hr). Pre-irradiation values of volume-averaged blood flow in the tumor ranged from 7 to 44 ml/min/100 g. Several hours after irradiation, blood flow fell by up to 50% for 60.5 Gy and up to 35% for 16.5 Gy. However, 24 hours after irradiation, tumor blood flow had recovered completely in the 16.5-Gy group and substantially in the others. For smaller doses such as the fractions typically employed in radiotherapy, no changes in tumor blood flow were observed

  20. Probing quantum gravity using photons from a flare of the active galactic nucleus Markarian 501 observed by the MAGIC telescope

    CERN Document Server

    Albert, J; Anderhub, H; Antonelli, L A; Antoranz, P; Backes, M; Baixeras, C; Barrio, J A; Bartko, H; Bastieri, D; Becker, J K; Bednarek, W; Berger, K; Bernardini, E; Bigongiari, C; Biland, A; Bock, R K; Bordas, P; Bosch-Ramon, V; Bretz, T; Britvitch, I; Camara, M; Carmona, E; Chilingarian, A; Commichau, S; Contreras, J L; Cortina, J; Costado, M T; Covino, S; Dazzi, F; De Angelis, A; De Cea del Pozo, E; Delgado Mendez, C; de los Reyes, R; De Lotto, B; De Maria, M; De Sabata, F; Dominguez, A; Dorner, D; Doro, M; Errando, M; Fagiolini, M; Ferenc, D; Fernández, E; Firpo, R; Fonseca, M V; Font, L; Galante, N; García-López, R J; Garczarczyk, M; Gaug, M; Göbel, F; Hayashida, M; Herrero, A; Höhne, D; Hose, J; Hsu, C C; Huber, S; Jogler, T; Kranich, D; La Barbera, A; Laille, A; Leonardo, E; Lindfors, E; Lombardi, S; Longo, F; López, M; Lorenz, E; Majumdar, P; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Mariotti, M; Martínez, M; Mazin, D; Meucci, M; Meyer, M; Miranda, J M; Mirzoyan, R; Moles, M; Moralejo, A; Nieto, D; Nilsson, K; Ninkovic, J; Otte, N; Oya, I; Panniello, M; Paoletti, R; Paredes, J M; Pasanen, M; Pascoli, D; Pauss, F; Pegna, R; Pérez-Torres, M A; Persic, M; Peruzzo, L; Piccioli, A; Prada, F; Puchades, N; Raymers, A; Ribó, M; Rico, J; Rissi, M; Robert, A; Rügamer, S; Saggion, A; Saitô, T; Salvati, M; Sanchez-Conde, M; Sartori, P; Satalecka, K; Scalzotto, V; Scapin, V; Schmitt, R; Schweizer, T; Shayduk, M; Shinozaki, K; Sidro, N; Sierpowska-Bartosik, A; Sillanpää, A; Spanier, F; Stamerra, A; Stark, L S; Takalo, L; Tavecchio, F; Temnikov, P; Tescaro, D; Teshima, M; Tluczykont, M; Torres, D F; Turini, N; Vankov, H; Venturini, A; Vitale, V; Wagner, R M; Wittek, W; Zabalza, M; Zandanel, F; Zanin, R; Ellis, Jonathan Richard; Mavromatos, N E; Nanopoulos, D V; Sakharov, Alexander S; Sarkisyan-Grinbaum, E

    2008-01-01

    We use the timing of photons observed by the MAGIC gamma-ray telescope during a flare of the active galaxy Markarian 501 to probe a vacuum refractive index ~ 1-(E/M_QGn)^n, n = 1,2, that might be induced by quantum gravity. The peaking of the flare is found to maximize for quantum-gravity mass scales M_QG1 ~ 0.4x10^18 GeV or M_QG2 ~ 0.6x10^11 GeV, and we establish lower limits M_QG1 > 0.26x10^18 GeV or M_QG2 > 0.39x10^11 GeV at the 95% C.L. Monte Carlo studies confirm the MAGIC sensitivity to propagation effects at these levels. Thermal plasma effects in the source are negligible, but we cannot exclude the importance of some other source effect.

  1. Analysis of the AMMON experimental program in the EOLE facility supporting the qualification of the JHR neutron and photon tools

    International Nuclear Information System (INIS)

    The first divergence of the international Jules Horowitz Material Testing Reactor under construction at CEA Cadarache is foreseen in 2016. In order to perform all the design and safety studies, a specific neutron and photon calculation tool, HORUS3D/N and P, dedicated to the JHR simulation, was developed. This development follows the V and V-UQ process; in this frame, the validation and qualification steps aim at quantifying all the biases and associated uncertainties of HORUS3D/N and P calculations. These biases originate from both the nuclear data and the calculation scheme, for calculations at step zero (JHR BOL core) or during depletion (JHR core at equilibrium). This paper focusses on the quantification of the biases due to nuclear data and the associated uncertainties. A new experimental program, named AMMON, was performed between 2010 and 2013 to provide experimental data for this quantification. A large part of the measurements has been today analyzed with the Monte Carlo TRIPOLI-4R code and the JEFF3.1.1 and EPDL97 data libraries relative to neutron/photon transport and photon emission. The C/E results were transposed from AMMON to JHR. The synthesis of the present analysis is very satisfactory. The calculation biases remains limited. In addition, thanks to a very good control to the experimental uncertainties during measurements, it is shown that the a priori uncertainties due to nuclear data for parameters at step zero was reduced up to a factor of 2. (authors)

  2. Dynamic performance of MEMS deformable mirrors for use in an active/adaptive two-photon microscope

    Science.gov (United States)

    Zhang, Christian C.; Foster, Warren B.; Downey, Ryan D.; Arrasmith, Christopher L.; Dickensheets, David L.

    2016-03-01

    Active optics can facilitate two-photon microscopic imaging deep in tissue. We are investigating fast focus control mirrors used in concert with an aberration correction mirror to control the axial position of focus and system aberrations dynamically during scanning. With an adaptive training step, sample-induced aberrations may be compensated as well. If sufficiently fast and precise, active optics may be able to compensate under-corrected imaging optics as well as sample aberrations to maintain diffraction-limited performance throughout the field of view. Toward this end we have measured a Boston Micromachines Corporation Multi-DM 140 element deformable mirror, and a Revibro Optics electrostatic 4-zone focus control mirror to characterize dynamic performance. Tests for the Multi-DM included both step response and sinusoidal frequency sweeps of specific Zernike modes. For the step response we measured 10%-90% rise times for the target Zernike amplitude, and wavefront rms error settling times. Frequency sweeps identified the 3dB bandwidth of the mirror when attempting to follow a sinusoidal amplitude trajectory for a specific Zernike mode. For five tested Zernike modes (defocus, spherical aberration, coma, astigmatism and trefoil) we find error settling times for mode amplitudes up to 400nm to be less than 52 us, and 3 dB frequencies range from 6.5 kHz to 10 kHz. The Revibro Optics mirror was tested for step response only, with error settling time of 80 μs for a large 3 um defocus step, and settling time of only 18 μs for a 400nm spherical aberration step. These response speeds are sufficient for intra-scan correction at scan rates typical of two-photon microscopy.

  3. Activation analysis in virus research

    International Nuclear Information System (INIS)

    Nucleic acids contain various amounts of trace elements. With divalent cations tobacco mosaic virus ribonucleic acid (TMV-RNA) undergoes changes in optical density at 258 mμ in both optical rotation and in sedimentation behaviour. These changes suggested the transformation from a random coil to a more orderly configuration. The connection between trace elements and the biological activity of TMV-RNA has been investigated. However, the relationship between metal ions and the virus infection process has not received much attention. This subject is discussed briefly in this paper. 8 refs

  4. Development and application of an automated analysis method for individual cerebral perfusion single photon emission tomography images

    CERN Document Server

    Cluckie, A J

    2001-01-01

    Neurological images may be analysed by performing voxel by voxel comparisons with a group of control subject images. An automated, 3D, voxel-based method has been developed for the analysis of individual single photon emission tomography (SPET) scans. Clusters of voxels are identified that represent regions of abnormal radiopharmaceutical uptake. Morphological operators are applied to reduce noise in the clusters, then quantitative estimates of the size and degree of the radiopharmaceutical uptake abnormalities are derived. Statistical inference has been performed using a Monte Carlo method that has not previously been applied to SPET scans, or for the analysis of individual images. This has been validated for group comparisons of SPET scans and for the analysis of an individual image using comparison with a group. Accurate statistical inference was obtained independent of experimental factors such as degrees of freedom, image smoothing and voxel significance level threshold. The analysis method has been eval...

  5. Role of two-photon electronic transitions in the formation of active dynamic conductivity in a three-barrier resonance tunneling structure with an applied Dc electric field

    International Nuclear Information System (INIS)

    The theory of active dynamic conductivity in a three-barrier resonance tunneling structure subjected to the combined action of a weak electromagnetic field and a longitudinal dc electric field is developed with regard for the contribution of laser induced one- and two-photon electronic transitions with different frequencies. For this purpose, the full Schroedinger equation is solved in the effective mass approximation and with the use of the model of rectangular potential wells and barriers for an electron. The maximum contribution of two-photon transitions to the formation of the total active dynamic conductivity in laser-induced transitions is shown not to exceed 38%. Geometric configurations of the resonance tunneling structure, for which the laser radiation intensity increases due to laser induced two-photon electronic transitions, are determined

  6. Neutron activation analysis of geochemical samples

    International Nuclear Information System (INIS)

    The present paper will describe the work done at the Technical Research Centre of Finland in developing methods for the large-scale activation analysis of samples for the geochemical prospecting of metals. The geochemical prospecting for uranium started in Finland in 1974 and consequently a manually operated device for the delayed neutron activation analysis of uranium was taken into use. During 1974 9000 samples were analyzed. The small capacity of the analyzer made it necessary to develop a completely automated analyzer which was taken into use in August 1975. Since then 20000-30000 samples have been analyzed annually the annual capacity being about 60000 samples when running seven hours per day. Multielemental instrumental neutron activation analysis is used for the analysis of more than 40 elements. Using instrumental epithermal neutron activation analysis 25-27 elements can be analyzed using one irradiation and 20 min measurement. During 1982 12000 samples were analyzed for mining companies and Geological Survey of Finland. The capacity is 600 samples per week. Besides these two analytical methods the analysis of lanthanoids is an important part of the work. 11 lanthanoids have been analyzed using instrumental neutron activation analysis. Radiochemical separation methods have been developed for several elements to improve the sensitivity of the analysis

  7. Recent developments in the theory of photon-photon collisions

    International Nuclear Information System (INIS)

    Over the past few years the field of photon-photon collisions has emerged as one of the best testing grounds for QCD, particularly in the area of exclusive and inclusive hard scattering processes, exotic resonance production, and detailed tests of the coupling of real and virtual photons to the quark current. In this summary of contributed papers, I will briefly review recent theoretical progress in the analysis of two-photon reactions and possible directions for future work. 29 references

  8. Epithermal Neutron Activation Analysis at the IBR-2 reactor of the Frank Laboratory of Neutron Physics at the Joint Institute for Nuclear Research (Dubna)

    Science.gov (United States)

    Frontasyeva, M. V.

    2008-10-01

    Experience of the Neutron Activation Analysis (NAA) Department in employing epithermal activation in life sciences and materials science is summarized. The potential of a combination of epithermal activation and the suppression of Compton scattering and contributions from cascade-photon-emitting elements for raising NAA-based analytical studies up to a new level are discussed.

  9. Microwave Photonics

    OpenAIRE

    A J Seeds; Liu, C. P.; Ismail, T; Fice, M. J.; Pozzi, F.; Steed, R. J.; Rouvalis, E.; Renaud, C.C.

    2010-01-01

    Microwave photonics is the use of photonic techniques for the generation, transmission, processing and reception of signals having spectral components at microwave frequencies. This tutorial reviews the technologies used and gives applications examples.

  10. Polychromatic photons

    DEFF Research Database (Denmark)

    Keller, Ole

    2002-01-01

    A review is given of the space-time wave mechanics of single photons, a subject with an almost century long history. The Landau-Peierls photon wave function, which is related nonlocally to the electromagnetic field is first described, and thereafter the so-called energy wave function, based on the...... positive-frequency Riemann-Silberstein vectors, is discussed. Recent attempts to understand the birth process of a photon emerging from a single atom are summarized. The polychromatic photon concept is introduced, and it is indicated how the wave mechanics of polychromatic photons can be upgraded to wave...... train quantum electrodynamics. A brief description of particle (photon) position operators is given, and it is shown that photons usually are only algebraically confined in an emission process. Finally, it is demonstrated that the profile of the birth domain of a radio-frequency photon emitted in a...

  11. Numerical analysis of single photon detection avalanche photodiodes operated in the Geiger mode

    Science.gov (United States)

    Sugihara, K.; Yagyu, E.; Tokuda, Y.

    2006-06-01

    For a wide range of the thicknesses of the charge and the multiplication layers, detection efficiency and dark count probability are numerically investigated for GaInAs/InP single photon detection avalanche photodiodes (APD's) which are operated in the Geiger mode. Breakdown probability and dark currents are calculated to evaluate detection efficiency and dark count probability. The result shows that dark count probability can be significantly reduced by increasing the thickness of the charge layer, whereas detection efficiency is expected to decline steeply at some thickness of the charge layer. Moreover, increasing the thickness of the multiplication layer does not continue to reduce dark count probability, which increases when the multiplication layer is thicker than a critical thickness. Finally, we show a design guideline of single photon detection APD's with higher detection efficiency and lower dark count probability.

  12. A parallel computational FDTD approach to the analysis of the light scattering from an opal photonic crystal

    Science.gov (United States)

    Vaccari, A.; Cala'Lesina, A.; Cristoforetti, L.; Chiappini, A.; Prudenzano, F.; Bozzoli, A.; Ferrari, M.

    2013-05-01

    This paper describes the parallel computational approach for the analysis of the multiple scattering of light from a three dimensional ensemble of many spherical particles having an ordered face-centered cubic lattice structure. The solution is obtained by numerically solving the Maxwell's equations using the FDTD (Finite Difference Time Domain) method with an impinging electromagnetic plane. The aim is to simulate the reflectance and transmittance of the system in the 300÷700 nm wavelength range, calculating also the angular power distribution of the scattered light. This study is suitable for the optical characterization of opal photonic crystals.

  13. theoretical analysis of finite-height semiconductor-on-insulator based planar photonic crystal waveguides

    DEFF Research Database (Denmark)

    Søndergaard, Thomas; Arentoft, Jesper

    2002-01-01

    A planar photonic crystal waveguide based on the semiconductor-on-insulator (SOI) materials system is analyzed theoretically. Two-dimensional (2-D) calculations and comparison with dispersion relations for the media above and below the finite-height waveguide are used to obtain design guidelines....... of light for the third frequency interval is explained theoretically by investigating the vertical localization of the guided modes....

  14. Analysis of the modal content into large-mode-area photonic crystal fibers under heat load

    OpenAIRE

    Coscelli, Enrico; Dauliat, Romain; Poli, Federica; Darwich, Dia; Cucinotta, Annamaria; Selleri, Stefano; Schuster, Kay; Benoit, Aurélien; Jamier, Raphaël; Roy, Philippe; Salin, François

    2015-01-01

    Thanks to their capability to provide very large mode area together with effective suppression of high-order modes, while allowing strong pump absorption and efficient conversion, Yb-doped double-cladding photonic crystal fibers are one of the key enabling factors for the development of high power fiber lasers. Thermal effects are currently appointed as the main bottleneck for future power scaling since, beyond a certain average power, they allow guidance of high order modes and energy transf...

  15. Low-dose photon irradiation alters cell differentiation via activation of hIK channels.

    Science.gov (United States)

    Roth, Bastian; Gibhardt, Christine S; Becker, Patrick; Gebhardt, Manuela; Knoop, Jan; Fournier, Claudia; Moroni, Anna; Thiel, Gerhard

    2015-08-01

    To understand the impact of ionizing irradiation from diagnostics and radiotherapy on cells, we examined K(+) channel activity before and immediately after exposing cells to X-rays. Already, low dose in the cGy range caused in adenocarcinoma A549 cells within minutes a hyperpolarization following activation of the human intermediate-conductance Ca(2+)-activated K(+) channel (hIK). The response was specific for cells, which functionally expressed hIK channels and in which hIK activity was low before irradiation. HEK293 cells, which do not respond to X-ray irradiation, accordingly develop a sensitivity to this stress after heterologous expression of hIK channels. The data suggest that hIK activation involves a Ca(2+)-mediated signaling cascade because channel activation is suppressed by a strong cytosolic Ca(2+) buffer. The finding that an elevation of H2O2 causes an increase in the concentration of cytosolic Ca(2+) suggests that radicals, which emerge early in response to irradiation, trigger this Ca(2+) signaling cascade. Inhibition of hIK channels by specific blockers clotrimazole and TRAM-34 slowed cell proliferation and migration in "wound" scratch assays; ionizing irradiation, in turn, stimulated the latter process presumably via its activation of the hIK channels. These data stress an indirect radiosensitivity of hIK channels with an impact on cell differentiation. PMID:25277267

  16. Photon Structure

    OpenAIRE

    Grindhammer, Guenter

    2001-01-01

    Large pT processes at HERA, initiated by almost real and by virtual photons, provide information on the structure of the photon. We report on the latest measurements of dijets and large pT particle production with the H1 detector. This includes a leading order determination of an effective virtual photon parton density, of the gluon density of the photon, and comparisons with models.

  17. Two-photon light-sheet nanoscopy by fluorescence fluctuation correlation analysis

    Science.gov (United States)

    Chen, Xuanze; Zong, Weijian; Li, Rongqin; Zeng, Zhiping; Zhao, Jia; Xi, Peng; Chen, Liangyi; Sun, Yujie

    2016-05-01

    Advances in light-sheet microscopy have enabled the fast three-dimensional (3D) imaging of live cells and bulk specimens with low photodamage and phototoxicity. Combining light-sheet illumination with super-resolution imaging is expected to resolve subcellular structures. Actually, such kind of super-resolution light-sheet microscopy was recently demonstrated using a single-molecule localization algorithm. However, the imaging depth and temporal resolution of this method are limited owing to the requirements of precise single molecule localization and reconstruction. In this work, we present two-photon super-resolution light-sheet imaging via stochastic optical fluctuation imaging (2PLS-SOFI), which acquires high spatiotemporal resolution and excellent optical sectioning ability. 2PLS-SOFI is based on non-linear excitation of fluctuation/blinking probes using our recently developed fast two-photon three-axis digital scanned light-sheet microscope (2P3A-DSLM), which enables both deep penetration and thin sheet of light. Overall, 2PLS-SOFI demonstrates up to 3-fold spatial resolution enhancement compared with conventional two-photon light-sheet (2PLS) microscopy and about 40-fold temporal resolution enhancement compared with individual molecule localization-selective plane illumination microscopy (IML-SPIM). Therefore, 2PLS-SOFI is promising for 3D long-term, deep-tissue imaging with high spatiotemporal resolution.

  18. Two-photon light-sheet nanoscopy by fluorescence fluctuation correlation analysis.

    Science.gov (United States)

    Chen, Xuanze; Zong, Weijian; Li, Rongqin; Zeng, Zhiping; Zhao, Jia; Xi, Peng; Chen, Liangyi; Sun, Yujie

    2016-05-21

    Advances in light-sheet microscopy have enabled the fast three-dimensional (3D) imaging of live cells and bulk specimens with low photodamage and phototoxicity. Combining light-sheet illumination with super-resolution imaging is expected to resolve subcellular structures. Actually, such kind of super-resolution light-sheet microscopy was recently demonstrated using a single-molecule localization algorithm. However, the imaging depth and temporal resolution of this method are limited owing to the requirements of precise single molecule localization and reconstruction. In this work, we present two-photon super-resolution light-sheet imaging via stochastic optical fluctuation imaging (2PLS-SOFI), which acquires high spatiotemporal resolution and excellent optical sectioning ability. 2PLS-SOFI is based on non-linear excitation of fluctuation/blinking probes using our recently developed fast two-photon three-axis digital scanned light-sheet microscope (2P3A-DSLM), which enables both deep penetration and thin sheet of light. Overall, 2PLS-SOFI demonstrates up to 3-fold spatial resolution enhancement compared with conventional two-photon light-sheet (2PLS) microscopy and about 40-fold temporal resolution enhancement compared with individual molecule localization-selective plane illumination microscopy (IML-SPIM). Therefore, 2PLS-SOFI is promising for 3D long-term, deep-tissue imaging with high spatiotemporal resolution. PMID:27121341

  19. Distortion-free spectrum sliced microwave photonic signal processor: analysis, design and implementation.

    Science.gov (United States)

    Li, Liwei; Yi, Xiaoke; Huang, Thomas X H; Minasian, Robert A

    2012-05-01

    A new switchable microwave photonic filter based on a novel spectrum slicing technique is presented. The processor enables programmable multi-tap generation with general transfer function characteristics and offers tunability, reconfigurabiliy, and switchability. It is based on connecting a dispersion controlled spectrum slicing filter after the modulated bipolar broadband light source, which consequently generates multiple spectrum slices with bipolarity, and compensates dispersion induced RF degradation simultaneously within a single device. A detailed theoretical model for this microwave photonic filter design is presented. Experimental results are presented which verify the model, and demonstrate a 33 bipolar-tap microwave filter with significant reduction of passband attenuations at high frequencies. The RF response improvement of the new microwave photonic filter is investigated, for both an ideal linear group delay line and for the experimental fiber delay line that has second order group delay and the results show that this new structure is effective for RF filters with various free spectral range values and spectrum slice bandwidths. Finally, a switchable bipolar filter that has a square-top bandpass filter response with more than 30 dB stopband attenuation that can be switched on/off via software control is demonstrated. PMID:22565771

  20. Theoretical Analysis of Spectral Correlations Between Photon Pairs Generated in Nanoscale Silicon Waveguides

    Science.gov (United States)

    Lu, Liang-Liang; Xu, Ping; Xu, Jian-Ning; He, Guang-Qiang; Zhu, Shi-Ning

    2015-12-01

    Spontaneous four wave mixing in nonlinear waveguide is one of the excellent technique for generating photon pairs in well-defined guided modes. Here we present a comprehensive study of the frequency characteristic of correlated photon pairs generated in telecom C-band from a dispersion-engineered silicon wire waveguide. We have demonstrated that the waveguide configuration, shape of pump pulse, two-photon absorption as well as linear losses have significant influences on the biphoton spectral characteristics and the amount of frequency entanglement generated. The superior performance as well as the structural compactness and CMOS compatibility makes the silicon wire waveguide an ideal integrated platform for the implementation of on-chip quantum technologies. Supported by the State Key Program for Basic Research of China under Grant No. 2012CB921802, the National Natural Science Foundation of China under Grant Nos. 91321312, 91121001, 11321063, 11174121, and 61475099, and the Project Funded by the Priority Academic Program Development of Jiangsu Higher Education Institutions (PAPD), and the Program for New Century Excellent Talents in University (NCET), and a Foundation for the Author of National Excellent Doctoral Dissertation of People's Republic of China (FANEDD)

  1. Dual-tunable multiferroic active ring filter for microwave photonic oscillators

    Science.gov (United States)

    Vitko, V. V.; Nikitin, A. A.; Ustinov, A. B.; Kalinikos, B. A.

    2015-12-01

    A theoretical model of a microwave active ring filter based on a ferrite-ferroelectric layered structure serving as a waveguide for spin-electromagnetic waves is developed. An experimental prototype of the device is fabricated and characterized. The device is implemented as an active-ring resonator with a microwave amplifier and a ferrite-ferroelectric delay line. The resonance properties of this system are studied theoretically and experimentally. The results show dual control of central frequency of the filter with magnetic and electric fields. An effective Q-factor of 50 000 and tuning by 5 MHz with an electric field are achieved at 8 GHz.

  2. Applications of neutron activation analysis in industry

    International Nuclear Information System (INIS)

    Neutron activation analysis technique is discussed in brief. This technique is used for quality control of raw materials, process materials and finished products, as well as activities in research and development for the improvement of the products and new products. The uses of this technique in several experienced industries are mentioned (author)

  3. Random access photonic metamaterials

    OpenAIRE

    Cencillo-Abad, P.; Ou, J.Y.; Valente, J.; Plum, E.; Zheludev, N.I.

    2015-01-01

    We demonstrate the first addressable reconfigurable photonic metamaterials thus enabling control over optical material properties with simultaneous spatial and temporal resolution. Potential applications of random access metadevices include active focusing, beam steering, dynamic transformation optics and video holography.

  4. A High-Speed, Event-Driven, Active Pixel Sensor Readout for Photon-Counting Microchannel Plate Detectors

    Science.gov (United States)

    Kimble, Randy A.; Pain, Bedabrata; Norton, Timothy J.; Haas, J. Patrick; Oegerle, William R. (Technical Monitor)

    2002-01-01

    Silicon array readouts for microchannel plate intensifiers offer several attractive features. In this class of detector, the electron cloud output of the MCP intensifier is converted to visible light by a phosphor; that light is then fiber-optically coupled to the silicon array. In photon-counting mode, the resulting light splashes on the silicon array are recognized and centroided to fractional pixel accuracy by off-chip electronics. This process can result in very high (MCP-limited) spatial resolution while operating at a modest MCP gain (desirable for dynamic range and long term stability). The principal limitation of intensified CCD systems of this type is their severely limited local dynamic range, as accurate photon counting is achieved only if there are not overlapping event splashes within the frame time of the device. This problem can be ameliorated somewhat by processing events only in pre-selected windows of interest of by using an addressable charge injection device (CID) for the readout array. We are currently pursuing the development of an intriguing alternative readout concept based on using an event-driven CMOS Active Pixel Sensor. APS technology permits the incorporation of discriminator circuitry within each pixel. When coupled with suitable CMOS logic outside the array area, the discriminator circuitry can be used to trigger the readout of small sub-array windows only when and where an event splash has been detected, completely eliminating the local dynamic range problem, while achieving a high global count rate capability and maintaining high spatial resolution. We elaborate on this concept and present our progress toward implementing an event-driven APS readout.

  5. On the photonic cellular interaction and the electric activity of neurons in the human brain

    Czech Academy of Sciences Publication Activity Database

    Salari, V.; Tuszynski, J. A.; Bokkon, I.; Rahnama, M.; Cifra, Michal

    Vol. 329. Bristol: IOP, 2011 - (Cifra, M.; Pokorny, J.; Kučera, O.), 012006 ISSN 1742-6588. [9th International Frohlich's Symposium on Electrodynamic Activity of Living Cells - Including Microtubule Coherent Modes and Cancer Cell Physics. Praha (CZ), 01.07.2011-03.07.2011] Institutional support: RVO:67985882 Keywords : Electric activity * Cellular interaction * Empirical evidence Subject RIV: JA - Electronics ; Optoelectronics, Electrical Engineering

  6. Twisted split-ring-resonator photonic metamaterial with huge optical activity

    CERN Document Server

    Decker, M; Soukoulis, C M; Linden, S; Wegener, M

    2010-01-01

    Coupled split-ring-resonator metamaterials have previously been shown to exhibit large coupling effects, which are a prerequisite for obtaining large effective optical activity. By a suitable lateral arrangement of these building blocks, we completely eliminate linear birefringence and obtain pure optical activity and connected circular optical dichroism. Experiments at around 100-THz frequency and corresponding modeling are in good agreement. Rotation angles of about 30 degrees for 205nm sample thickness are derived.

  7. Neutrons and Photons in Nondestructive Detection

    Science.gov (United States)

    Harmon, J. F.; Wells, D. P.; Hunt, A. W.

    2011-02-01

    Active, nondestructive interrogation with neutrons and photons has seen a renaissance in recent years, owing to a broad spectrum of important applications in security, nuclear nonproliferation, contraband detection and materials analysis. Active methods are of high interest for such applications because they provide at least an order of magnitude greater sensitivity than passive methods. Accelerator-based neutron and photon active methods exploit two important factors to attain greater sensitivity: these are (i) the control of interrogating beam properties such as directionality, energy, intensity, polarization and the temporal distribution of radiation; (ii) well-founded, low energy nuclear physics that yields distinct "signatures" for elemental and isotopic content. This review addresses accelerator-based neutron and photon nondestructive testing methods and issues when applied to modern and emerging wide-ranging challenges in nondestructive detection.

  8. New studies in forensic neutron activation analysis

    International Nuclear Information System (INIS)

    Three recently completed studies in forensic neutron activation analysis are reported: a study of 0.22-caliber rimfire cartridge primers, a large-scale study of shotgun pellets, and a new 5-element procedure for the analysis of bullet-lead and shotgun-pellet samples. (author) 12 refs

  9. New studies in forensic neutron activation analysis

    International Nuclear Information System (INIS)

    Earlier studies in forensic neutron activation analysis are being extended in This Laboratory. Three of these new studies are reported here: 1) a study of 0.22-caliber rimfire cartridge primers, 2) a large-scale study of shotgun pellets, and 3) a new 5-element procedure for the analysis of bullet-lead and shotgun-pellet samples. (author)

  10. A program for activation analysis data processing

    International Nuclear Information System (INIS)

    An ALGOL program for activation analysis data handling is presented. The program may be used either for single channel spectrometry data or for multichannel spectrometry. The calculation of instrumental error and of analysis standard deviation is carried out. The outliers are tested, and the regression line diagram with the related observations are plotted by the program. (author)

  11. Prompt photons at the LHC : selection, measurements of single- and di-photon production cross sections, and Higgs boson searches with the ATLAS detector

    CERN Document Server

    Marchiori, Giovanni

    This document, prepared to obtain the "Habilitation à Diriger des Recherches", is a compendium of the photon-related analysis activities I carried on within ATLAS in the past four years and a half. The activities I will describe can be broadly classified into three categories: optimization and/or in situ measurement of photon-related performance, measurements of the cross sections of Standard Model processes producing prompt photons, and searches (leading to discovery!) of a Standard Model Higgs boson decaying to final states containing photons.

  12. Evaluation of business activity using financial analysis

    OpenAIRE

    Kučerová, Martina

    2012-01-01

    Czech University of Life Sciences Prague Faculty of Economics and Management Department of Trade and Accounting Abstract of Diploma Thesis Evaluation of business activity using financial analysis Martina Kučerová © 2012 CULS in Prague Summary: The aim of this thesis is to apply methods of financial analysis on chosen business for its first three accounting periods 2009, 2010 and 2011. The thesis is further analysis of my bachelor thesis on to...

  13. Photon Counts Statistics in Leukocyte Cell Dynamics

    International Nuclear Information System (INIS)

    In the present experiment ultra-weak photon emission/chemiluminescence from isolated neutrophils was recorded. It is associated with the production of reactive oxygen species (ROS) in the 'respiratory burst' process which can be activated by PMA (Phorbol 12-Myristate 13-Acetate). Commonly, the reaction is demonstrated utilizing the enhancer luminol. However, with the use of highly sensitive photomultiplier equipment it is also recorded without enhancer. In that case, it can be hypothesized that photon count statistics may assist in understanding the underlying metabolic activity and cooperation of these cells. To study this hypothesis leukocytes were stimulated with PMA and increased photon signals were recorded in the quasi stable period utilizing Fano factor analysis at different window sizes. The Fano factor is defined by the variance over the mean of the number of photon within the observation time. The analysis demonstrated that the Fano factor of true signal and not of the surrogate signals obtained by random shuffling increases when the window size increased. It is concluded that photon count statistics, in particular Fano factor analysis, provides information regarding leukocyte interactions. It opens the perspective to utilize this analytical procedure in (in vivo) inflammation research. However, this needs further validation.

  14. Activation analysis in science and technics

    International Nuclear Information System (INIS)

    Physical bases of the method of neutron activation analysis are described. Reactions of element nuclei with neutrons, gamma quanta and charged particles, ways of radioactivity measurement, gamma spectrometry in particular, have been described. The method errors, as well as element determination sensitivity in samples of different composition are considered, perspectives of activation analysis development being reflected. The practical use of the method in the studies on solid-state physics, during the analysis of semiconductors and pure materials, in criminalistics, agriculture, the environmnental control in geology and biology, is shown

  15. Coupling Analysis of Electromagnetic Field Transverse Magnetic (TM) on 2D Photonic Crystals with Symmetrical Refractive Index Defect Using Tensor Green Method

    CERN Document Server

    Kurniawan, Candra

    2012-01-01

    Photonic crystal is a dielectric material which has a refractive index or permittivity which vary periodically, thus preventing the propagation of light with specific frequency and direction. The frequency range is called a photonic bandgap (PBG). If the structure of photonic crystals is modified by taking one line of rod in a photonic crystal is obtained a waveguide. Giving structures with symmetrical defects around the waveguide channel with the parameters given occurs coupling between the waveguide and cavity. Coupling indicates transfer part or all of the EM field depends on the frequency of EM field in the photonic crystal. Green tensor method can be used to calculate the total electric field in a 2D photonic crystal. With the aid of MATLAB programs can be shown to the powerful visualization calculation of the total electrical field in 2D photonic crystals. Based on analysis of the literature and the bandgap graphic and the field energy in the defects show that effective frequency which produces maximum ...

  16. Heavy quark production in photon-nucleon and photon-photon collisions

    OpenAIRE

    Szczurek, A.

    2002-01-01

    We discuss several mechanisms of heavy quark production in (real) photon-nucleon and (real) photon - (real) photon collisions. In particular we focuse on application of the Saturation Model. We discuss how to generalize the formula from virtual photon - proton scattering and analyze threshold effects. We discuss a possibility to measure the cross section for $\\gamma \\gamma \\to 2 c 2 \\bar c$. In addition to the main dipole-dipole contribution included in a recent analysis, we propose how to ca...

  17. Measuring the Photon Fragmentation Function at HERA

    CERN Document Server

    Ridder, A G D; Poulsen, E

    2006-01-01

    The production of final state photons in deep inelastic scattering originates from photon radiation off leptons or quarks involved in the scattering process. Photon radiation off quarks involves a contribution from the quark-to-photon fragmentation function, corresponding to the non-perturbative transition of a hadronic jet into a single, highly energetic photon accompanied by some limited hadronic activity. Up to now, this fragmentation function was measured only in electron-positron annihilation at LEP. We demonstrate by a dedicated parton-level calculation that a competitive measurement of the quark-to-photon fragmentation function can be obtained in deep inelastic scattering at HERA. Such a measurement can be obtained by studying the photon energy spectra in $\\gamma + (0+1)$-jet events, where $\\gamma$ denotes a hadronic jet containing a highly energetic photon (the photon jet). Isolated photons are then defined from the photon jet by imposing a minimal photon energy fraction. For this so-called democratic...

  18. Applicability of effective medium description to photonic crystals in higher bands: Theory and numerical analysis

    Science.gov (United States)

    Markel, Vadim A.; Tsukerman, Igor

    2016-06-01

    We consider conditions under which photonic crystals (PCs) can be homogenized in the higher photonic bands and, in particular, near the Γ point. By homogenization we mean introducing some effective local parameters ɛeff and μeff that describe reflection, refraction, and propagation of electromagnetic waves in the PC adequately. The parameters ɛeff and μeff can be associated with a hypothetical homogeneous effective medium. In particular, if the PC is homogenizable, the dispersion relations and isofrequency lines in the effective medium and in the PC should coincide to some level of approximation. We can view this requirement as a necessary condition of homogenizability. In the vicinity of a Γ point, real isofrequency lines of two-dimensional PCs can be close to mathematical circles, just like in the case of isotropic homogeneous materials. Thus, one may be tempted to conclude that introduction of an effective medium is possible and, at least, the necessary condition of homogenizability holds in this case. We, however, show that this conclusion is incorrect: complex dispersion points must be included into consideration even in the case of strictly nonabsorbing materials. By analyzing the complex dispersion relations and the corresponding isofrequency lines, we have found that two-dimensional PCs with C4 and C6 symmetries are not homogenizable in the higher photonic bands. We also draw a distinction between spurious Γ -point frequencies that are due to Brillouin-zone folding of Bloch bands and "true" Γ -point frequencies that are due to multiple scattering. Understanding of the physically different phenomena that lead to the appearance of spurious and "true" Γ -point frequencies is important for the theory of homogenization.

  19. Analysis of Charged Particle/Photon Correlations in Hadronic Multiparticle Production

    CERN Document Server

    Bjorken, James D

    2003-01-01

    In order to analyze data on joint charged-particle/photon distributions from an experimental search (T-864, MiniMax) for disoriented chiral condensate (DCC) at the Fermilab Tevatron collider, we have identified robust observables, ratios of normalized bivariate factorial moments, with many desirable properties. These include insensitivity to many efficiency corrections and the details of the modeling of the primary pion production, and sensitivity to the production of DCC, as opposed to the generic, binomial-distribution partition of pions into charged and neutral species. The relevant formalism is developed and tested in Monte-Carlo simulations of the MiniMax experimental conditions.

  20. RF-photonic chirp encoder and compressor for seamless analysis of information flow.

    Science.gov (United States)

    Zalevsky, Zeev; Shemer, Amir; Zach, Shlomo

    2008-05-26

    In this paper we realize an RF photonic chirp compression system that compresses a continuous stream of incoming RF data (modulated on top of an optical carrier) into a train of temporal short pulses. Each pulse in the train can be separated and treated individually while being sampled by low rate optical switch and without temporal loses of the incoming flow of information. Each such pulse can be filtered and analyzed differently. The main advantage of the proposed system is its capability of being able to handle, seamlessly, high rate information flow with all-optical means and with low rate optical switches. PMID:18545501

  1. Ultrafast polarization optical switch constructed from one-dimensional photonic crystal and its performance analysis

    Institute of Scientific and Technical Information of China (English)

    WANG Tao; LI Qing; GAO DingShan

    2009-01-01

    All-optical switch with the ultrafast optical switching rate is a key device in the next generation optical network. In this article, we propose a polarization switch with ps switching time, which is constructed from one-dimensional resonant photonic crystal (1D RPC). The model of switch operating at 1.5 μm is established based on the optical stark effect (OSE). We calculate the performance indices of the switch and the influences of errors of periods and refractive index on the performance characteristics.

  2. Integrated frequency comb source based Hilbert transformer for wideband microwave photonic phase analysis.

    Science.gov (United States)

    Nguyen, Thach G; Shoeiby, Mehrdad; Chu, Sai T; Little, Brent E; Morandotti, Roberto; Mitchell, Arnan; Moss, David J

    2015-08-24

    We demonstrate a photonic RF Hilbert transformer for broadband microwave in-phase and quadrature-phase generation based on an integrated frequency optical comb, generated using a nonlinear microring resonator based on a CMOS compatible, high-index contrast, doped-silica glass platform. The high quality and large frequency spacing of the comb enables filters with up to 20 taps, allowing us to demonstrate a quadrature filter with more than a 5-octave (3 dB) bandwidth and an almost uniform phase response. PMID:26368182

  3. Analysis of photonic band-gap (PBG) structures using the FDTD method

    DEFF Research Database (Denmark)

    Tong, M.S.; Cheng, M.; Lu, Y.L.;

    2004-01-01

    In this paper, a number of photonic band-gap (PBG) structures, which are formed by periodic circuit elements printed oil transmission-line circuits, are studied by using a well-known numerical method, the finite-difference time-domain (FDTD) method. The results validate the band-stop filter...... behavior of these structures, and the computed results generally match well with ones published in the literature. It is also found that the FDTD method is a robust, versatile, and powerful numerical technique to perform such numerical studies. The proposed PBG filter structures may be applied in microwave...

  4. Analysis of cutoff frequency in a one-dimensional superconductor-metamaterial photonic crystal

    Science.gov (United States)

    Aly, Arafa H.; Aghajamali, Alireza; Elsayed, Hussein A.; Mobarak, Mohamed

    2016-09-01

    In this paper, using the two-fluid model and the characteristic matrix method, we investigate the transmission characteristics of the one-dimensional photonic crystal. Our structure composed of the layers of low-temperature superconductor material (NbN) and double-negative metamaterial. We target studying the effect of many parameters such as the thickness of the superconductor material, the thickness of the metamaterial layer, and the operating temperature. We show that the cut-off frequency can be tuned efficiently by the operating temperature as well as the thicknesses of the constituent materials.

  5. ANALYSIS OF INDEXED-GUIDED HIGHLY BIREFRINGENT PHOTONIC CRYSTAL FIBER EMPLOYING DIFFERENT CLADDING GEOMETRIES

    Directory of Open Access Journals (Sweden)

    A. M. Jouri

    2015-07-01

    Full Text Available      In this paper, a comparative study of three geometries of highly birefringent photonic crystal fibers (HB PCF is presented. The proposed geometries are: V type PCF, Pseudo-Panda PCF and selectively liquid-filled PCF. Based on the famous Finite Difference Time Domain (FDTD method with the perfectly matched layer (PML boundary condition, the simulations are carried out in the aim to find a tradeoff between the chromatic dispersion, the birefringence and the confinement loss.

  6. Scattering loss analysis and structure optimization of hollow-core photonic bandgap fiber

    Science.gov (United States)

    Song, Jingming; Wu, Rong; Sun, Kang; Xu, Xiaoliang

    2016-06-01

    Effects of core structure in 7 cell hollow-core photonic bandgap fibers (HC-PBGFs) on scattering loss are analyzed by means of investigating normalized interface field intensity. Fibers with different core wall thickness, core radius and rounding corner of air hole are simulated. Results show that with thick core wall and expanded core radius, scattering loss could be greatly reduced. The scattering loss of the HC-PBGFs in the wavelength range of 1.5-1.56 μm could be decreased by about 50 % of the present level with optimized core structure design.

  7. Recent developments for an active UF6 gas target for photon-induced fission experiments

    Directory of Open Access Journals (Sweden)

    Freudenberger M.

    2013-12-01

    Full Text Available Recent developments for an active uranium-hexafluoride-loaded gas target as well as results on the detector gas properties are presented. The gas of choice is a mixture of argon with small amounts of UF6. This contribution presents the experimental setup and focusses on the electron drift velocity with increasing UF6 content. A time-dependent decrease in electron drift velocity is observed in our setup.

  8. Recent developments for an active UF6 gas target for photon-induced fission experiments

    OpenAIRE

    Freudenberger M.; Eckardt C.; Enders J.; Göök A.; von Neumann-Cosel P.; Oberstedt A.; Oberstedt S.

    2013-01-01

    Recent developments for an active uranium-hexafluoride-loaded gas target as well as results on the detector gas properties are presented. The gas of choice is a mixture of argon with small amounts of UF6. This contribution presents the experimental setup and focusses on the electron drift velocity with increasing UF6 content. A time-dependent decrease in electron drift velocity is observed in our setup.

  9. Human hair neutron activation analysis: analysis on population level, mapping

    International Nuclear Information System (INIS)

    Neutron activation analysis is an outstanding analytical method having very wide applications in various fields. Analysis of human hair within last decades mostly based on neutron activation analysis is a very attractive illustration of the application of nuclear analytical techniques. Very interesting question is how the elemental composition differs in different areas or cities. In this connection the present paper gives average data and maps of various localities in the vicinity of drying-out Aral Sea and of various industrial cities in Central Asia. (author)

  10. Lidar Waveform-Based Analysis of Depth Images Constructed Using Sparse Single-Photon Data

    Science.gov (United States)

    Altmann, Yoann; Ren, Ximing; McCarthy, Aongus; Buller, Gerald S.; McLaughlin, Steve

    2016-05-01

    This paper presents a new Bayesian model and algorithm used for depth and intensity profiling using full waveforms from the time-correlated single photon counting (TCSPC) measurement in the limit of very low photon counts. The model proposed represents each Lidar waveform as a combination of a known impulse response, weighted by the target intensity, and an unknown constant background, corrupted by Poisson noise. Prior knowledge about the problem is embedded in a hierarchical model that describes the dependence structure between the model parameters and their constraints. In particular, a gamma Markov random field (MRF) is used to model the joint distribution of the target intensity, and a second MRF is used to model the distribution of the target depth, which are both expected to exhibit significant spatial correlations. An adaptive Markov chain Monte Carlo algorithm is then proposed to compute the Bayesian estimates of interest and perform Bayesian inference. This algorithm is equipped with a stochastic optimization adaptation mechanism that automatically adjusts the parameters of the MRFs by maximum marginal likelihood estimation. Finally, the benefits of the proposed methodology are demonstrated through a serie of experiments using real data.

  11. Lidar Waveform-Based Analysis of Depth Images Constructed Using Sparse Single-Photon Data.

    Science.gov (United States)

    Altmann, Yoann; Ren, Ximing; McCarthy, Aongus; Buller, Gerald S; McLaughlin, Steve

    2016-05-01

    This paper presents a new Bayesian model and algorithm used for depth and reflectivity profiling using full waveforms from the time-correlated single-photon counting measurement in the limit of very low photon counts. The proposed model represents each Lidar waveform as a combination of a known impulse response, weighted by the target reflectivity, and an unknown constant background, corrupted by Poisson noise. Prior knowledge about the problem is embedded through prior distributions that account for the different parameter constraints and their spatial correlation among the image pixels. In particular, a gamma Markov random field (MRF) is used to model the joint distribution of the target reflectivity, and a second MRF is used to model the distribution of the target depth, which are both expected to exhibit significant spatial correlations. An adaptive Markov chain Monte Carlo algorithm is then proposed to perform Bayesian inference. This algorithm is equipped with a stochastic optimization adaptation mechanism that automatically adjusts the parameters of the MRFs by maximum marginal likelihood estimation. Finally, the benefits of the proposed methodology are demonstrated through a series of experiments using real data. PMID:26886984

  12. Calculation and analysis of photon dose equivalent distributions in the ICRU sphere

    International Nuclear Information System (INIS)

    Detailed dose equivalent distributions have been calculated in the ICRU sphere by Monte Carlo methods for photons in the energy range 0.010 - 10.0 MeV using the kerma approximation, with statistical accuracy generally better than +- 1%. Results are presented as depth-dose distributions along the principal axis and other selected axes and as isodose distributions, for parallel unidirectional, parallel opposed, planar rotational, planar isotropic and spatially isotropic irradiation. Various DE quantities are discussed and their numerical values presented as functions of photon energy. Six appendices are included which discuss (I.) conversion factors for different basic normalisation quantities, (II.) briefly the Monte Carlo procedure used, (III.) the meaning of kerma and the kerma approximation, (IV.) a comparison of the work presented in this report and the calculations of Dimbylow in 1983, (V.) a test experiment using a 30 cm spherical phantom, (VI.) the results of backscatter measurements and calculations using a 30 cm spherical phantom and cubic phantoms. (orig.)

  13. UNESCO active learning approach in optics and photonics leads to significant change in Morocco

    Science.gov (United States)

    Berrada, K.; Channa, R.; Outzourhit, A.; Azizan, M.; Oueriagli, A.

    2014-07-01

    There are many difficulties in teaching science and technology in developing countries. Several different teaching strategies have to be applied in these cases. More specifically, for developing countries competencies in teaching science in the introductory classroom has attracted much attention. As a specific example we will consider the Moroccan system. In most developing countries everything is moving so slowly that the progress stays static for development. Also, any change needs time, effort and engagement. In our case we discovered that many teachers feel uncomfortable when introducing new teaching methods and evaluation in classes at introductory physics. However, the introduction of an Active Learning in our curricula showed difficulties that students have in understanding physics and especially concepts. Students were interested in having Active Learning courses much more than passive and traditional ones. Changing believes on physical phenomena and reality of the world students become more attractive and their way of thinking Science changed. The main philosophy of fostering modern hands-on learning techniques -adapted to local needs and availability of teaching resources- is elaborated. The Active Learning program provides the teachers with a conceptual evaluation instrument, drawn from relevant physics education research, giving teachers an important tool to measure student learning. We will try to describe the UNESCO Chair project in physics created in 2010 at Cadi Ayyad University since our first experience with UNESCO ALOP program. Many efforts have been done so far and the project helps now to develop more national and international collaborations between universities and Regional Academies of Education and Training. As a new result of these actions and according to our local needs, the translation of the ALOP program into Arabic is now available under the auspice of UNESCO and encouragement of international partners SPIE, ICTP, ICO and OSA.

  14. Active quenching circuit for a InGaAs single-photon avalanche diode

    International Nuclear Information System (INIS)

    We present a novel gated operation active quenching circuit (AQC). In order to simulate the quenching circuit a complete SPICE model of a InGaAs SPAD is set up according to the I–V characteristic measurement results of the detector. The circuit integrated with aROIC (readout integrated circuit) is fabricated in an CSMC 0.5 μm CMOS process and then hybrid packed with the detector. Chip measurement results show that the functionality of the circuit is correct and the performance is suitable for practical system applications. (semiconductor integrated circuits)

  15. Neutron-photon mixed field dosimetry by TLD-700 glow curve analysis and its implementation in dose monitoring for Boron Neutron Capture Therapy (BNCT) treatments

    Energy Technology Data Exchange (ETDEWEB)

    Boggio, E. F.; Longhino, J. M. [Centro Atomico Bariloche, Departamento de Fisica de Reactores y Radiaciones / CNEA, Av. E. Bustillo Km 9.5, R8402AGP San Carlos de Bariloche (Argentina); Andres, P. A., E-mail: efboggio@cab.cnea.gov.ar [Centro Atomico Bariloche, Division Proteccion Radiologica / CNEA, Av. E. Bustillo Km 9.5, R8402AGP San Carlos de Bariloche (Argentina)

    2015-10-15

    BNCT is a cancerous cells selective, non-conventional radiotherapy modality to treat malignant tumors such as glioblastoma, melanoma and recurrent head and neck cancer. It consists of a two-step procedure: first, the patient is injected with a tumor localizing drug containing a non-radioactive isotope (Boron-10) with high slow neutron capture cross-section. In a second step, the patient is irradiated with neutrons, which are absorbed by the Boron-10 agent with the subsequently nuclear reaction B- 10(n,a)Li-7, thereby resulting in dose at cellular level due to the high-Let particles. The neutron fields suitable for BNCT are characterized by high neutron fluxes and low gamma dose. Determination of each component is not an easy task, especially when the volume of measurement is quite small or inaccessible for a miniature ionization chamber, for example. A method of measuring the photon and slow neutron dose(mainly by N-14 and B-10) from the glow curve (GC) analysis of a single {sup 7}LiF thermoluminescence detector is evaluated. This method was suggested by the group headed by Dr. Grazia Gambarini. The dosemeters used were TLD-600 ({sup 6}LiF:Mg,Ti with 95.6% {sup 6}Li) and TLD-700 ({sup 7}LiF:Mg,Ti with 99.9% {sup 7}LiF) from Harshaw. Photon dose measurement using the GC analysis method with TLD-700 in mixed fields requires the relation of the two main peaks of a TLD-600 GC shape obtained from an exposition to the same neutron field, and a photon calibrated GC with TLD-700. The requirements for slow neutron dose measurements are similar. In order to properly apply the GC analysis method at the Ra-6 Research Reactor BNCT facility, measurements were carried out in a standard water phantom, fully characterized on the BNCT beam by conventional techniques (activation detectors and paired ionization chambers technique). Next, the method was implemented in whole body dose monitoring of a patient undergoing a BNCT treatment, using a Bo MAb (Bottle Manikin Absorption) phantom

  16. Neutron-photon mixed field dosimetry by TLD-700 glow curve analysis and its implementation in dose monitoring for Boron Neutron Capture Therapy (BNCT) treatments

    International Nuclear Information System (INIS)

    BNCT is a cancerous cells selective, non-conventional radiotherapy modality to treat malignant tumors such as glioblastoma, melanoma and recurrent head and neck cancer. It consists of a two-step procedure: first, the patient is injected with a tumor localizing drug containing a non-radioactive isotope (Boron-10) with high slow neutron capture cross-section. In a second step, the patient is irradiated with neutrons, which are absorbed by the Boron-10 agent with the subsequently nuclear reaction B- 10(n,a)Li-7, thereby resulting in dose at cellular level due to the high-Let particles. The neutron fields suitable for BNCT are characterized by high neutron fluxes and low gamma dose. Determination of each component is not an easy task, especially when the volume of measurement is quite small or inaccessible for a miniature ionization chamber, for example. A method of measuring the photon and slow neutron dose(mainly by N-14 and B-10) from the glow curve (GC) analysis of a single 7LiF thermoluminescence detector is evaluated. This method was suggested by the group headed by Dr. Grazia Gambarini. The dosemeters used were TLD-600 (6LiF:Mg,Ti with 95.6% 6Li) and TLD-700 (7LiF:Mg,Ti with 99.9% 7LiF) from Harshaw. Photon dose measurement using the GC analysis method with TLD-700 in mixed fields requires the relation of the two main peaks of a TLD-600 GC shape obtained from an exposition to the same neutron field, and a photon calibrated GC with TLD-700. The requirements for slow neutron dose measurements are similar. In order to properly apply the GC analysis method at the Ra-6 Research Reactor BNCT facility, measurements were carried out in a standard water phantom, fully characterized on the BNCT beam by conventional techniques (activation detectors and paired ionization chambers technique). Next, the method was implemented in whole body dose monitoring of a patient undergoing a BNCT treatment, using a Bo MAb (Bottle Manikin Absorption) phantom, with representative

  17. Activation analysis as applied to environmental substances

    International Nuclear Information System (INIS)

    The historical background of activation analysis as applied to environmental problems is first briefly described. Then, the present state of its utilization for environmental samples, mainly atmospheric floating particles and human hairs, is reviewed. The problem with irradiation reactors is also mentioned. In the activation analysis of environmental substances, the instrumental neutron activation analysis (INAA) with the thermal neutrons in reactors is the main; besides, there are the methods with bremsstrahlung, etc. The INAA is most effectively used for atmospheric airborne particles and the micro-elements in human hairs. In Japan, the INAA is currently employed by the Environmental Agency in its national air pollution surveillance network for metallic pollutants. The problem with reactors is the limited capacity for thermal neutron irradiation. (Mori, K.)

  18. Neutron activation spectrometry and neutron activation analysis in analytical geochemistry

    International Nuclear Information System (INIS)

    The present report is to show the geochemists who are interested in neutron activation spectrometry (NAS) and neutron activation analysis (NAA) which analytical possibilities these methods offer him. As a review of these analytical possibilities, a lieterature compolation is given which is subdivided into two groups: 1) rock (basic, intermediary, acid, sediments, soils and nuds, diverse minerals, tectites, meteorites and lunar material). 2) ore (Al, Au, Be, Cr, Cu, Mn, Mo, Fe, Pb, Pt, Sn, Ti, W, Zn, Zr, U and phosphate ore, polymetallic ores, fluorite, monazite and diverse ores). The applied methods as well as the determinable elements in the given materials can be got from the tables. On the whole, the literature evaluation carried out makes it clear that neutron activation spectrometry is a very useful multi-element method for the analysis of rocks. The analysis of ores, however, is subjected to great limitations. As rock analysis is very frequently of importance in prospecting for ore deposits, the NAS proves to be extremely useful for this very field of application. (orig./LH)

  19. High-capacity neutron activation analysis facility

    International Nuclear Information System (INIS)

    A high-capacity neutron activation analysis facility, the Reactor Activation Facility, was designed and built and has been in operation for about a year at one of the Savannah River Plant's production reactors. The facility determines uranium and about 19 other elements in hydrogeochemical samples collected in the National Uranium Resource Evaluation program, which is sponsored and funded by the United States Department of Energy, Grand Junction Office. The facility has a demonstrated average analysis rate of over 10,000 samples per month, and a peak rate of over 16,000 samples per month. Uranium is determined by cyclic activation and delayed neutron counting of the U-235 fission products; other elements are determined from gamma-ray spectra recorded in subsequent irradiation, decay, and counting steps. The method relies on the absolute activation technique and is highly automated for round-the-clock unattended operation

  20. Activation analysis of air particulate matter

    International Nuclear Information System (INIS)

    This review on activation analysis of air particulate matter is an extended and updated version of a review given by the same authors in 1985. The main part is aimed at the analytical scheme and refers to rules and techniques for sampling, sample and standard preparation, irradiation and counting procedures, as well as data processing, - evaluation, and - presentation. Additional chapters deal with relative and monostandard methods, the use of activation analysis for atmosphere samples in various localities, and level of toxic and other elements in the atmosphere. The review contains 190 references. (RB)

  1. Prospects for absolute neutron activation analysis

    International Nuclear Information System (INIS)

    The desirability for absolute neutron activation analysis(ANAA) is two-fold. Results by the comparitor method are only as good as the standards used, and also the method offers a chance of having the final results available within minutes of completing the analysis. In the past ANAA was not seriously considered because of the scarcity and poor qaulity of the nuclear data that were available. This situation is however steadily improving and the possible applications are being investigated. This report reviews the present status by considering the basic activation equation, calculation of parameters, the factors of importance and the size error one might expect

  2. Design of Neutron Activation Analysis Laboratorium Room

    International Nuclear Information System (INIS)

    Base on the planning to increase of the research and service quality in the ''Neutron activation analysis'' (APN),the design of mentioned ''Neutron activation analysis laboratories room'' has been done in the multi purpose reactor G.A. Siwabessy. By the using the designed installation, the irradiation preparation and counting sample can be done. The design doing by determination of installation lay out and maximum particle contain in the air. The design installation required a unit of 1 HP blower, a unit of 1 HP split air condition and 2 units 1200 x 800 mm HEPA filter. This paper concluded that this design is feasible to fabricated

  3. Two-Photon Correlation Spectroscopy in Single Dendritic Spines Reveals Fast Actin Filament Reorganization during Activity-Dependent Growth.

    Directory of Open Access Journals (Sweden)

    Jian-Hua Chen

    Full Text Available Two-photon fluorescence correlation spectroscopy (2P-FCS within single dendritic spines of living hippocampal pyramidal neurons was used to resolve various subpopulations of mobile F-actin during activity-dependent structural changes such as potentiation induced spine head growth. Two major classes of mobile F-actin were discovered: very dynamic and about a hundred times less dynamic F-actin. Spine head enlargement upon application of Tetraethylammonium (TEA, a protocol previously used for the chemical induction of long-term potentiation (cLTP strictly correlated to changes in the dynamics and filament numbers in the different actin filament fractions. Our observations suggest that spine enlargement is governed by a mechanism in which longer filaments are first cut into smaller filaments that cooperate with the second, increasingly dynamic shorter actin filament population to quickly reorganize and expand the actin cytoskeleton within the spine head. This process would allow a fast and efficient spine head enlargement using a major fraction of the actin filament population that was already present before spine head growth.

  4. Displacement damage analysis and modified electrical equivalent circuit for electron and photon-irradiated silicon solar cells

    Science.gov (United States)

    Arjhangmehr, Afshin; Feghhi, Seyed Amir Hossein

    2014-10-01

    Solar modules and arrays are the conventional energy resources of space satellites. Outside the earth's atmosphere, solar panels experience abnormal radiation environments and because of incident particles, photovoltaic (PV) parameters degrade. This article tries to analyze the electrical performance of electron and photon-irradiated mono-crystalline silicon (mono-Si) solar cells. PV cells are irradiated by mono-energetic electrons and poly-energetic photons and immediately characterized after the irradiation. The mean degradation of the maximum power (Pmax) of silicon solar cells is presented and correlated using the displacement damage dose (Dd) methodology. This method simplifies evaluation of cell performance in space radiation environments and produces a single characteristic curve for Pmax degradation. Furthermore, complete analysis of the results revealed that the open-circuit voltage (Voc) and the filling factor of mono-Si cells did not significantly change during the irradiation and were independent of the radiation type and fluence. Moreover, a new technique is developed that adapts the irradiation-induced effects in a single-cell equivalent electrical circuit and adjusts its elements. The "modified circuit" is capable of modeling the "radiation damage" in the electrical behavior of mono-Si solar cells and simplifies the designing of the compensation circuits.

  5. Strained Silicon Photonics

    Directory of Open Access Journals (Sweden)

    Ralf B. Wehrspohn

    2012-05-01

    Full Text Available A review of recent progress in the field of strained silicon photonics is presented. The application of strain to waveguide and photonic crystal structures can be used to alter the linear and nonlinear optical properties of these devices. Here, methods for the fabrication of strained devices are summarized and recent examples of linear and nonlinear optical devices are discussed. Furthermore, the relation between strain and the enhancement of the second order nonlinear susceptibility is investigated, which may enable the construction of optically active photonic devices made of silicon.

  6. Photonic Lantern

    CERN Document Server

    Leon-Saval, Sergio; Bland-Hawthorn, Joss

    2015-01-01

    Photonic lanterns allow for a low-loss transformation of a multimode waveguide into a discrete number of single-mode waveguides and vice versa, thus, enabling the use of single-mode photonic technologies in multimode systems. In this review, we will discuss the theory and function of the photonic lantern, along with several different variants of the technology. We will also discuss some of its applications in more detail.

  7. Absorbed dose behavior and photons fluency study as photons beam penetration function applied to mammography: a comparative analysis between BR12 homogeneous model and a realistic voxel model

    International Nuclear Information System (INIS)

    The aim of this work is to describe the absorbed dose and the spectra radiation behavior as function of photon beam penetration. To realize this were simulated three sensitive volumes were simulated, each one with dimensions (0.010 x 0.010 x 0.001) m3 in different positions into the model (top, medium and button). The MCNP (version 4B) was used to simulate the virtual reality of mammographic procedure for BR12 models 0.040 m and 0.080 m thicker for target-add filter combination of Mo-30Mo and Mo-25Rh and tube tensions between 24 kVp and 34 kVp, in steps of 2 kVp. For voxel breast model simulations were executed considering the realistic possibility 28 kVp with 30 μm add filtration and 30 kVp with 25 μm Rh add filtration, both with Mo target. The simulation mimics Lorad MIII mammographic equipment. In this process the absorbed dose and the spectra were recorded for each selected situation, considering polyenergetic photons beams and monoenergetic photons beams (the last one in steps of 5kV). Comparing the models with homogeneous composition and the voxel model was found significant difference behavior presented on shape spectra and spectra area, and on absorbed dose by each sensitive volume position. (author)

  8. Photonic crystal fibers -

    DEFF Research Database (Denmark)

    Libori, Stig E. Barkou

    2002-01-01

    possibilities, the thesis will attempot to offer a proof of concept, rather than an in-depth analysis, thus reflecting the present state of the art within the area of micro-structured fibers. Another important sub-class of micro-structured fibers is photonic bandgap fibers. Photonic bandgap fibers are far more......-structured fibers that guide light by simple index effects. However, photonic bandgap fibers offer more radical possibilities, such as core regions with an effective index that is lower than the surrounding effective cladding index one may guide light in air- and dispersion qualities that differ from both those of...

  9. QCD analysis of isolated photon and jet data from ep, pp, and p anti p collisions and tests of αs running

    International Nuclear Information System (INIS)

    A QCD analysis of the cross section for the production of an isolated photon with an accompanying jet in deep inelastic ep scattering (DIS) at HERA is presented. A description of the relevant measurement is given, made with the ZEUS detector. A fit of the Parton Density Functions (PDFs) of the proton, to isolated photon and inclusive DIS data, is done. The sensitivity to the low x composition of the quark sea is studied. The extracted ratio of the sea u and d quark PDFs at x→0 is consistent with unity, as expected by isospin symmetry. The level of presence of additional partons in a proton, apart from quarks and gluons (e.g. photons), is estimated, and found to be about or below 1%. The running of the strong coupling constant, αs(μ), is tested in a QCD analysis using jet measurements at LHC, Tevatron and HERA in combination with inclusive DIS data. Here μ is associated with the energy scale in the process, typically with the jet transverse energy. For the αs running test, the parameter nf of the running, which gives the number of active quarks contributing to loop corrections of the jet and DIS cross sections, is replaced by nf+Δnf at energy scales greater than μ>μthresh. A series of simultaneous αs(MZ)+Δnf+proton PDF ts to world collider cross section data is done at Next-to-Leading Order QCD, for μthresh values ranging from 1 GeV to 1 TeV. The fitted Δnf is consistent with zero at all tested scales, which gives a precise quantitative confirmation of the QCD running of αs over 3 orders of magnitude in energy scale. The presented method also provides a new way for indirect searches of physics beyond the Standard Model (SM). Constraints are derived on models suggesting physics beyond the SM, which contain loop corrections to the jet and DIS cross sections, and for which a change of the measured configuration of the final state can be neglected. Power pulsing studies are reported of the Mimosa26 pixel sensor, which is the rst sensor prototype for the

  10. Sensitivity enhancement of short time activation analysis by pulse activation

    International Nuclear Information System (INIS)

    TRIGA-reactors have the unique possibility of increasing the power by a factor of up to 1200, to produce a corresponding up to 1200 fold increase in flux by pulsing the reactor. This feature is, however, seldom applied for activation analysis owing to the fact that the sensitivity enhancement is optimal only for short lived nuclides or isometric states in the sub-second range of half lives. As the maximal information density is confined to a short time interval, a fast transfer system and a measuring system allowing to handle the extremely high countrates are imperative. Both systems now being commercially available, it is possible to overcome the major draw back of conventional activation analysis, namely the long time delay between arrival of the sample and obtaining the results, for those elements having short lived nuclides or isomeric states

  11. Parallel FE Electron-Photon Transport Analysis on 2-D Unstructured Mesh

    International Nuclear Information System (INIS)

    A novel solution method has been developed to solve the coupled electron-photon transport problem on an unstructured triangular mesh. Instead of tackling the first-order form of the linear Boltzmann equation, this approach is based on the second-order form in conjunction with the conventional multi-group discrete-ordinates approximation. The highly forward-peaked electron scattering is modeled with a multigroup Legendre expansion derived from the Goudsmit-Saunderson theory. The finite element method is used to treat the spatial dependence. The solution method is unique in that the space-direction dependence is solved simultaneously, eliminating the need for the conventional inner iterations, a method that is well suited for massively parallel computers

  12. Performance and capacity analysis of Poisson photon-counting based Iter-PIC OCDMA systems.

    Science.gov (United States)

    Li, Lingbin; Zhou, Xiaolin; Zhang, Rong; Zhang, Dingchen; Hanzo, Lajos

    2013-11-01

    In this paper, an iterative parallel interference cancellation (Iter-PIC) technique is developed for optical code-division multiple-access (OCDMA) systems relying on shot-noise limited Poisson photon-counting reception. The novel semi-analytical tool of extrinsic information transfer (EXIT) charts is used for analysing both the bit error rate (BER) performance as well as the channel capacity of these systems and the results are verified by Monte Carlo simulations. The proposed Iter-PIC OCDMA system is capable of achieving two orders of magnitude BER improvements and a 0.1 nats of capacity improvement over the conventional chip-level OCDMA systems at a coding rate of 1/10. PMID:24216821

  13. Analysis of single-photon time resolution of FBK silicon photomultipliers

    Science.gov (United States)

    Acerbi, Fabio; Ferri, Alessandro; Gola, Alberto; Zorzi, Nicola; Piemonte, Claudio

    2015-07-01

    We characterized and analyzed an important feature of silicon photomultipliers: the single-photon time resolution (SPTR). We characterized the SPTR of new RGB (Red-Green-Blue) type Silicon Photomultipliers and SPADs produced at FBK (Trento, Italy), studying its main limiting factors. We compared time resolution of 1×1 mm2 and 3×3 mm2 SiPMs and a single SiPM cell (i.e. a SPAD with integrated passive-quenching), employing a mode-locked pulsed laser with 2-ps wide pulses. We estimated the contribution of front-end electronic-noise, of cell-to-cell uniformity, and intrinsic cell time-resolution. At a single-cell level, we compared the results obtained with different layouts. With a circular cell with a top metallization covering part of the edge and enhancing the signal extraction, we reached ~20 ps FWHM of time resolution.

  14. Design and analysis of equiangular spiral photonic crystal fiber for mid-infrared supercontinuum generation

    Science.gov (United States)

    Saini, T. S.; Baili, A.; Kumar, A.; Cherif, R.; Zghal, M.; Sinha, R. K.

    2015-11-01

    A design of equiangular spiral photonic crystal fiber (PCF) in As2Se3 chalcogenide glass is reported for mid-infrared supercontinuum generation. Supercontinuum covering the 1.2-15 μm molecular fingerprint region is achieved using only 8 mm long designed PCF pumped with 50 fs laser pulses of 500 W peak power. The structural parameters have been tailored for all-normal dispersion characteristic. Proposed structure has high nonlinearity (γ = 12474 W-1 km-1) at 3.5 μm with very low and flat dispersion -2.9 [ps/(nm × km)]. Supercontinuum with such broadening and high coherence degree is applicable for mid-infrared spectroscopy, gas sensing, early cancer diagnostics and free space communication.

  15. Field test analysis of concentrator photovoltaic system focusing on average photon energy and temperature

    Science.gov (United States)

    Husna, Husyira Al; Ota, Yasuyuki; Minemoto, Takashi; Nishioka, Kensuke

    2015-08-01

    The concentrator photovoltaic (CPV) system is unique and different from the common flat-plate PV system. It uses a multi-junction solar cell and a Fresnel lens to concentrate direct solar radiation onto the cell while tracking the sun throughout the day. The cell efficiency could reach over 40% under high concentration ratio. In this study, we analyzed a one year set of environmental condition data of the University of Miyazaki, Japan, where the CPV system was installed. Performance ratio (PR) was discussed to describe the system’s performance. Meanwhile, the average photon energy (APE) was used to describe the spectrum distribution at the site where the CPV system was installed. A circuit simulator network was used to simulate the CPV system electrical characteristics under various environmental conditions. As for the result, we found that the PR of the CPV systems depends on the APE level rather than the cell temperature.

  16. Analysis of a highly birefringent asymmetric photonic crystal fibre based on a surface plasmon resonance sensor

    Science.gov (United States)

    Liu, Chao; Wang, Famei; Zheng, Shijie; Sun, Tao; Lv, Jingwei; Liu, Qiang; Yang, Lin; Mu, Haiwei; Chu, Paul K.

    2016-07-01

    A highly birefringent photonic crystal fibre is proposed and characterized based on a surface plasmon resonance sensor. The birefringence of the sensor is numerically analyzed by the finite-element method. In the numerical simulation, the resonance wavelength can be directly positioned at this birefringence abrupt change point and the depth of the abrupt change of birefringence reflects the intensity of excited surface plasmon. Consequently, the novel approach can accurately locate the resonance peak of the system without analyzing the loss spectrum. Simulated average sensitivity is as high as 1131 nm/RIU, corresponding to a resolution of 1 × 10-4 RIU in this sensor. Therefore, results obtained via the approach not only show polarization independence and less noble metal consumption, but also reveal better performance in terms of accuracy and computation efficiency.

  17. Complete Analysis of Four-Photon χ-Type Entangled State via Cross-Kerr Nonlinearity

    Science.gov (United States)

    Zeng, Zhi; Li, Xi-Han; Wang, Chun; Wang, Li-Li; Liu, Zhen-Zhen; Wei, Hua

    2015-09-01

    We propose an efficient method to construct an optical four-photon |χ> state analyzer via the cross-Kerr nonlinearity combined with linear optical elements. In this protocol, two four-qubit parity-check gates and two controlled phase gates are employed. We show that all the 16 orthogonal four-qubit |χ> states can be completely discriminated with our apparatus. The scheme is feasible and realizable with current technology. It may have useful potential applications in quantum information processing which based on |χ> state. Supported by the National Natural Science Foundation of China under Grant No. 11004258, and Fundamental Research Funds for the Central Universities Project under Grant No. CQDXWL-2012-014, the Natural Science Foundation Project of CQ CSTC 2011jjA90017

  18. Integration of electronics and photonics in active material by femtosecond laser for functional microdevice fabrication

    Science.gov (United States)

    Cheng, Ya; Xu, Zhizhan; Sugioka, Koji; Midorikawa, Katsumi

    2010-02-01

    Recently, hybrid integration of multifunctional micro-components for creating complex, intelligent micro/nano systems has attracted significant attention. These micro/nano systems have important applications in a variety of areas, such as healthcare, environment, communication, national security, and so on. Until now, fabrication of micro/nano systems incorporated with different functions is still a challenging issue, which generally requires fabrication of microcomponents beforehand followed by assembly and packaging procedures. Thus, the fabrication process is complex and costly. In recent years, the rapid development of femtosecond laser microfabrication technology has enabled direct fabrication and integration of multifunctional components, such as microfluidics, microoptics, micromechanics, microelectronics, etc., into a substrate. Particularly, in this talk, we show the use of femtosecond laser microfabrication for integrating microelectronics and microphotonics. Both microelectrodes and optical waveguides can be directly embedded in active materials after a femtosecond laser direct writing followed by electroless chemical plating. As examples, electric-optic (EO) modulators were fabricated in lithium niobate (LiNbO3) crystal and their functions were demonstrated.

  19. Quality assurance in biomedical neutron activation analysis

    International Nuclear Information System (INIS)

    The summary report represents an attempt to identify some of the possible sources of error in in vitro neutron activation analysis of trace elements applied to specimens of biomedical origin and to advise on practical means to avoid them. The report is intended as guidance for all involved in analysis, including sample collection and preparation for analysis. All these recommendations constitute part of quality assurance which is here taken to encompass the two concepts - quality control and quality assessment. Quality control is the mechanism established to control errors, while quality assessment is the mechanism used to verify that the analytical procedure is operating within acceptable limits

  20. Microwave photonics

    CERN Document Server

    Lee, Chi H

    2006-01-01

    Wireless, optical, and electronic networks continue to converge, prompting heavy research into the interface between microwave electronics, ultrafast optics, and photonic technologies. New developments arrive nearly as fast as the photons under investigation, and their commercial impact depends on the ability to stay abreast of new findings, techniques, and technologies. Presenting a broad yet in-depth survey, Microwave Photonics examines the major advances that are affecting new applications in this rapidly expanding field.This book reviews important achievements made in microwave photonics o

  1. Photonic glasses

    CERN Document Server

    Gan, Fuxi

    2006-01-01

    This book introduces the fundamental mechanism of photonic glasses - the linear and nonlinear optical effects in glass under intense light irradiation: phot-induced absorption, refraction, polarization, frequency, coherence and monochromaticity changes. Emphasis is placed on new developments in the structure, spectroscopy and physics of new glassy materials for photonics applications, such as optical communication, optical data storage, new lasers and new photonic components and devices. The book presents the research results of the authors in new glasses for photonics over the last decade. Sa

  2. Transforming Teacher Education, An Activity Theory Analysis

    Science.gov (United States)

    McNicholl, Jane; Blake, Allan

    2013-01-01

    This paper explores the work of teacher education in England and Scotland. It seeks to locate this work within conflicting sociocultural views of professional practice and academic work. Drawing on an activity theory framework that integrates the analysis of these seemingly contradictory discourses with a study of teacher educators' practical…

  3. The Atomic Fingerprint: Neutron Activation Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Keisch, Bernard [Carnegie-Mellon University

    1972-01-01

    The nuclei of atoms are stable only when they contain certain numbers of neutrons and protons. Since nuclei can absorb additional neutrons, which in many cases results in the conversion of a stable nucleus to a radioactive one, neutron activation analysis is possible.

  4. Prompt gamma-ray activation analysis (PGAA)

    Energy Technology Data Exchange (ETDEWEB)

    Kern, J. [Fribourg Univ. (Switzerland). Inst. de Physique

    1996-11-01

    The paper deals with a brief description of the principles of prompt gamma-ray activation analysis (PGAA), with the detection of gamma-rays, the PGAA project at SINQ and with the expected performances. 8 figs., 3 tabs., 10 refs.

  5. Isotopic neutron sources for neutron activation analysis

    International Nuclear Information System (INIS)

    This User's Manual is an attempt to provide for teaching and training purposes, a series of well thought out demonstrative experiments in neutron activation analysis based on the utilization of an isotopic neutron source. In some cases, these ideas can be applied to solve practical analytical problems. 19 refs, figs and tabs

  6. Neutron Activation Analysis with k0 Standardization

    International Nuclear Information System (INIS)

    SCK-CEN's programme on Neutron Activation Analysis with k0-standardisation aims to: (1) develop and implement k0-standardisation method for NAA; (2) to exploit the inherent qualities of NAA such as accuracy, traceability, and multi-element capability; (3) to acquire technical spin-off for nuclear measurements services. Main achievements in 1997 are reported

  7. Neutron activation analysis helps in picture attribution

    International Nuclear Information System (INIS)

    The neutron activation analysis application for obtaining the data useful for proper attribution of paintings has been presented on the base of several examples. The identification on this way of dye elements, pigments and other painting materials is an important element among the physico-chemical methods helping the attribution procedure of old painting objects

  8. Processes related to photon-photon collisions

    International Nuclear Information System (INIS)

    Two types of processes, related to photon-photon collisions, are considered: deep inelastic Compton scattering, and photon pair production. The relevant theoretical and experimental literature is reviewed

  9. Establishment of a brain perfusion single photon emission computed tomography database in children by statistical imaging analysis

    International Nuclear Information System (INIS)

    We made a 3-dimensional, 99mTc-ECD brain perfusion single photon emission computed tomography (SPECT) database in children by a statistical analysis. We selected 52 individuals between 1 and 15 years of age whose brain SPECT and brain MRI findings were normal, and divided them into three age groups: 1-5, 6-10 and 11-15 years. By comparing databases obtained for each group, an age-dependent change of regional cerebral blood flow was investigated. The results showed that the relative blood flow increases in the frontal lobe and cerebeller hemisphere and decrease in the occipital lobe with increasing age, findings consistent with those of previous reports. This database enabled us to easily find 3-dimensional brain perfusion abnormality in individual patient by SPECT, and may help elucidate the pathophysiology of many brain disorders. (author)

  10. Development and application of an automated analysis method for individual cerebral perfusion single photon emission tomography images

    International Nuclear Information System (INIS)

    Neurological images may be analysed by performing voxel by voxel comparisons with a group of control subject images. An automated, 3D, voxel-based method has been developed for the analysis of individual single photon emission tomography (SPET) scans. Clusters of voxels are identified that represent regions of abnormal radiopharmaceutical uptake. Morphological operators are applied to reduce noise in the clusters, then quantitative estimates of the size and degree of the radiopharmaceutical uptake abnormalities are derived. Statistical inference has been performed using a Monte Carlo method that has not previously been applied to SPET scans, or for the analysis of individual images. This has been validated for group comparisons of SPET scans and for the analysis of an individual image using comparison with a group. Accurate statistical inference was obtained independent of experimental factors such as degrees of freedom, image smoothing and voxel significance level threshold. The analysis method has been evaluated for application to cerebral perfusion SPET imaging in ischaemic stroke. It has been shown that useful quantitative estimates, high sensitivity and high specificity may be obtained. Sensitivity and the accuracy of signal quantification were found to be dependent on the operator defined analysis parameters. Recommendations for the values of these parameters have been made. The analysis method developed has been compared with an established method and shown to result in higher specificity for the data and analysis parameter sets tested. In addition, application to a group of ischaemic stroke patient SPET scans has demonstrated its clinical utility. The influence of imaging conditions has been assessed using phantom data acquired with different gamma camera SPET acquisition parameters. A lower limit of five million counts and standardisation of all acquisition parameters has been recommended for the analysis of individual SPET scans. (author)

  11. Computational Models for Analysis of Illicit Activities

    DEFF Research Database (Denmark)

    Nizamani, Sarwat

    devise policies to minimize them. These activities include cybercrimes, terrorist attacks or violent actions in response to certain world issues. Beside such activities, there are several other related activities worth analyzing, for which computational models have been presented in this thesis....... These models include a model for analyzing evolution of terrorist networks; a text classification model for detecting suspicious text and identification of suspected authors of anonymous emails; and a semantic analysis model for news reports, which may help analyze the illicit activities in certain area...... with location and temporal information. For the network evolution, the hierarchical agglomerative clustering approach has been applied to terrorist networks as case studies. The networks' evolutions show that how individual actors who are initially isolated from each other are converted in small groups, which...

  12. Analysis by neutron activation analysis a some ancient Dacian ceramics

    CERN Document Server

    Olariu, A

    1999-01-01

    Ancient Dacian ceramics, from three different establishments from Romanian territory have been analyzed by neutron activation analysis. A series of elements has been determined: Ba, Eu, K, La, Mn, Na, Sc, Sm. Ba is the element that could be considered to differentiate relatively the three groups of ceramics.

  13. Neutron activation analysis of Etruscan pottery

    International Nuclear Information System (INIS)

    Neutron activation analysis (NAA) has been widely used in archaeology for compositional analysis of pottery samples taken from sites of archaeological importance. Elemental profiles can determine the place of manufacture. At Cornell, samples from an Etruscan site near Siena, Italy, are being studied. The goal of this study is to compile a trace element concentration profile for a large number of samples. These profiles will be matched with an existing data bank in an attempt to understand the place of origin for these samples. The 500 kW TRIGA reactor at the Ward Laboratory is used to collect NAA data for these samples. Experiments were done to set a procedure for the neutron activation analysis with respect to sample preparation, selection of irradiation container, definition of activation and counting parameters and data reduction. Currently, we are able to analyze some 27 elements in samples of mass 500 mg with a single irradiation of 4 hours and two sequences of counting. Our sensitivity for many of the trace elements is better than 1 ppm by weight under the conditions chosen. In this talk, details of our procedure, including quality assurance as measured by NIST standard reference materials, will be discussed. In addition, preliminary results from data treatment using cluster analysis will be presented. (author)

  14. Alpha hemolysin induces an increase of erythrocytes calcium: a FLIM 2-photon phasor analysis approach.

    Directory of Open Access Journals (Sweden)

    Susana Sanchez

    Full Text Available α-Hemolysin (HlyA from Escherichia coli is considered as the prototype of a family of toxins called RTX (repeat in toxin, a group of proteins that share genetic and structural features. HlyA is an important virulence factor in E. coli extraintestinal infections, such as meningitis, septicemia and urinary infections. High concentrations of the toxin cause the lysis of several cells such as erythrocytes, granulocytes, monocytes, endothelial and renal epithelial cells of different species. At low concentrations it induces the production of cytokines and apoptosis. Since many of the subcytolytic effects in other cells have been reported to be triggered by the increase of intracellular calcium, we followed the calcium concentration inside the erythrocytes while incubating with sublytic concentrations of HlyA. Calcium concentration was monitored using the calcium indicator Green 1, 2-photon excitation, and fluorescence lifetime imaging microscopy (FLIM. Data were analyzed using the phasor representation. In this report, we present evidence that, at sublytic concentrations, HlyA induces an increase of calcium concentration in rabbit erythrocytes in the first 10 s. Results are discussed in relation to the difficulties of measuring calcium concentrations in erythrocytes where hemoglobin is present, the contribution of the background and the heterogeneity of the response observed in individual cells.

  15. Numerical analysis for a solid-core photonic crystal fiber with tunable zero dispersion wavelengths

    Science.gov (United States)

    Barrientos-García, A.; Sukoivanov, Igor A.; Andrade-Lucio, J. A.; Guryev, Igor; Shulika, Oleksiy V.; Hernandez-García, J. C.; Ramos-Ortiz, G.

    2014-09-01

    Here we propose a simple design for a solid-core photonic crystal fiber made of silica by keeping the golden ratio (1.618) between pitch and air hole diameter Λ /d in a subset of six rings of air-holes with hexagonal arrangement. In the case when we have a pitch equal to one micron (Λ =1 μm), we need air-holes diameters d=0.618 μm in order to obtain the golden ratio parameter (Λ/d=1.618), and achieve two zero dispersion wavelength (ZDW) points at 725 nm and 1055 nm; this gives us the possibility to use this fiber in supercontinuum generation using a laser emission close to that points. We analyzed a series of fibers using this relation and show the possibilities of tunable ZDW in a wide range of wavelengths from 725 nm to 2000 nm with low losses and small effective area. In agreement with the ZDW point needed, the geometry of the structure can be modified to the point of having only three rings of air holes that surround the solid core with low losses and good confinement mode. The design proposed here is analyzed using the finite element method (FEM) with perfectly matched layers (PML), including the material dispersion directly into the model applying the Sellmeier's equation.

  16. Resonances in photon-photon scattering

    International Nuclear Information System (INIS)

    A quantity called stickiness is introduced which should be largest for J not equal to 0 glueballs and can be measured in two photon scattering and radiative J/psi decay. An argument is reviewed suggesting that light J = 0 glueballs may have large couplings to two photons. The analysis of radiative decays of eta and eta' is reviewed and a plea made to desist from false claims that they are related to GAMMA(π0 → γγ) by SU(3) symmetry. It is shown that two photon studies can refute the difficult-to-refute hypothesis that xi(2220) or zeta(8320) are Higgs bosons. A gallery of rogue resonances and resonance candidates is presented which would usefully be studied in γγ scattering, including especially the low mass dipion. 34 references

  17. Computer modeling for neutron activation analysis methods

    International Nuclear Information System (INIS)

    Full text: The INP AS RU develops databases for the neutron-activation analysis - ND INAA [1] and ELEMENT [2]. Based on these databases, the automated complex is under construction aimed at modeling of methods for natural and technogenic materials analysis. It is well known, that there is a variety of analysis objects with wide spectra, different composition and concentration of elements, which makes it impossible to develop universal methods applicable for every analytical research. The modelling is based on algorithm, that counts the period of time in which the sample was irradiated in nuclear reactor, providing the sample's total absorption and activity analytical peaks areas with given errors. The analytical complex was tested for low-elemental analysis (determination of Fe and Zn in vegetation samples, and Cu, Ag and Au - in technological objects). At present, the complex is applied for multielemental analysis of sediment samples. In this work, modern achievements in the analytical chemistry (measurement facilities, high-resolution detectors, IAEA and IUPAC databases) and information technology applications (Java software, database management systems (DBMS), internet technologies) are applied. Reference: 1. Tillaev T., Umaraliev A., Gurvich L.G., Yuldasheva K., Kadirova J. Specialized database for instrumental neutron activation analysis - ND INAA 1.0, The 3-rd Eurasian Conference Nuclear Science and its applications, 2004, pp.270-271.; 2. Gurvich L.G., Tillaev T., Umaraliev A. The Information-analytical database on the element contents of natural objects. The 4-th International Conference Modern problems of Nuclear Physics, Samarkand, 2003, p.337. (authors)

  18. Multiscale statistical analysis of coronal solar activity

    CERN Document Server

    Gamborino, Diana; Martinell, Julio J

    2016-01-01

    Multi-filter images from the solar corona are used to obtain temperature maps which are analyzed using techniques based on proper orthogonal decomposition (POD) in order to extract dynamical and structural information at various scales. Exploring active regions before and after a solar flare and comparing them with quiet regions we show that the multiscale behavior presents distinct statistical properties for each case that can be used to characterize the level of activity in a region. Information about the nature of heat transport is also be extracted from the analysis.

  19. Service activities of chemical analysis division

    International Nuclear Information System (INIS)

    Progress of the Division during the year of 1988 was described on the service activities for various R and D projects carrying out in the Institute, for the fuel fabrication and conversion plant, and for the post-irradiation examination facility. Relevant analytical methodologies developed for the chemical analysis of an irradiated fuel, safeguards chemical analysis, and pool water monitoring were included such as chromatographic separation of lanthanides, polarographic determination of dissolved oxygen in water, and automation on potentiometric titration of uranium. Some of the laboratory manuals revised were also included in this progress report. (Author)

  20. Conference on instrumental activation analysis IAA 86

    International Nuclear Information System (INIS)

    Thirty five papers were presented at the conference held in Klucenice, Czechoslovakia from May 4 to 8, 1986. The abstracts of all papers are printed in the proceedings. The conference discussed the following problem areas: the application of activation analysis in determining elements in ores, tectites, fungi, the thyroid, the primary circuit coolant, semiconductor materials; the application of nuclear reaction analysis in determining elements in rubber and coal; the application of tracer techniques in metallurgy; the description of alpha and gamma spectrometric systems and their testing; the use of microcomputers for data processing, and the description of programs. (J.P.)

  1. Model of a photon

    Directory of Open Access Journals (Sweden)

    Alexandrov B. L.

    2015-09-01

    Full Text Available The article examines the historical aspect of the appearance of the concept of the photon, which was introduced through the works of Planck, Einstein, Compton, Lewis. It is noted that the photon has both corpuscular characteristics (momentum, mass, energy and wave (frequency, wavelength, which are interconnected. Thus, the photon has dual properties – of a particle and a wave. The article deals with the analysis described in the literature of the photon model proposed by S.M. Polyakov and O.S. Polyakova, F.M. Konarevym-Krauzerom, V.G.Kozlovym and S.I. Chervyakov, as well as with their advantages and disadvantages. A version of the model in the form of a photon of two identical but oppositely charged halfmass, which simultaneously perform translational, rotational and vibrational motion was suggested. We have shown derivation of the amplitude of vibration of the two half-mass photon connected with simple relation with wavelength, described with this photon. On this basis, it is concluded that the state of a photon is characterized by a rotational movement of its oppositely charged half-stuff, which radius (r is the amplitude of the oscillation process of each of the half-mass, and described by oppositely charged half-mass circumference length S in expanded form in a result of the progressive movement is the length wave l. This work displays the wave equation describing the motion of photons in the form of a standing wave which is a complete analog-independent Schrödinger equation for the motion of an electron in a hydrogen atom

  2. Unparticle effects in photon-photon scattering

    OpenAIRE

    Chang, Chun-Fu; Cheung, Kingman; Yuan, Tzu-Chiang

    2008-01-01

    Elastic photon-photon scattering can only occur via loop diagrams in the standard model and is naturally suppressed. Unparticle can induce tree-level photon-photon scattering through the operator F_{\\mu\

  3. Nondestructive gamma activation analysis of mineral materials

    International Nuclear Information System (INIS)

    The basic problems are described related to the use of gamma activation analysis. The applicability was studied of instrumental gamma activation analysis (IGAA) in geology. A number of minerals, rocks, marine sediments and reference materials were studied. For irradiation a betatron and a microtron were used. The results show that IGAA allows the simultaneous determination of a number of trace elements at concentrations of tenths of ppm. The results are given of comparisons made of the analytical possibilities of microtron IGAA and reactor INAA in geology. Tables show the results of the application of IGAA, the main products and parameters of photoexcitation reactions and graphically represented are the gamma spectra of measured materials. (J.B.)

  4. KFUPM fast neutron activation analysis facility

    International Nuclear Information System (INIS)

    A newly established Fast Neutron Activation Analysis facility at the Energy Research Laboratory is described. The facility mainly consists of a fast neutron irradiation station and a gamma ray counting station. Both stations are connected by a fast pneumatic sample transfer system which transports the sample from the irradiation station to the counting station in a short time of 3 s. The fast neutron activation analysis facility has been tested by measuring the 27A(n, α)24Na and 115In(n, n')115mIn cross sections at 14.8 and 2.5 MeV neutron energies, respectively. Within the experimental uncertainties, the measured cross sections for these elements agree with the published values. (orig.)

  5. The impact of photon flight path on S1 pulse shape analysis in liquid xenon two-phase detectors

    International Nuclear Information System (INIS)

    The LUX dark matter search experiment is a 350 kg dual-phase xenon time projection chamber located at the 4850 ft level of the Sanford Underground Research Facility in Lead, SD. The success of two-phase xenon detectors for dark matter searches relies on their ability to distinguish electron recoil (ER) background events from nuclear recoil (NR) signal events. Typically, the NR-ER discrimination is obtained from the ratio of the electroluminescence light (S2) to the prompt scintillation light (S1). Analysis of the S1 pulse shape is an additional discrimination technique that can be used to distinguish NR from ER. Pulse-shape NR-ER discrimination can be achieved based on the ratio of the de-excitation processes from singlet and triplet states that generate the S1. The NR S1 is dominated by the de-excitation process from singlet states with a time constant of about 3 ns while the ER S1 is dominated by the de-excitation process from triplet states with a time constant of about 24 ns. As the size of the detectors increases, the variation in the S1 photon flight path can become comparable to these decay constants, reducing the utility of pulse-shape analysis to separate NR from ER. The effect of path length variations in the LUX detector has been studied using the results of simulations and the impact on the S1 pulse shape analysis is discussed

  6. The impact of photon flight path on S1 pulse shape analysis in liquid xenon two-phase detectors

    Science.gov (United States)

    Moongweluwan, M.

    2016-02-01

    The LUX dark matter search experiment is a 350 kg dual-phase xenon time projection chamber located at the 4850 ft level of the Sanford Underground Research Facility in Lead, SD. The success of two-phase xenon detectors for dark matter searches relies on their ability to distinguish electron recoil (ER) background events from nuclear recoil (NR) signal events. Typically, the NR-ER discrimination is obtained from the ratio of the electroluminescence light (S2) to the prompt scintillation light (S1). Analysis of the S1 pulse shape is an additional discrimination technique that can be used to distinguish NR from ER. Pulse-shape NR-ER discrimination can be achieved based on the ratio of the de-excitation processes from singlet and triplet states that generate the S1. The NR S1 is dominated by the de-excitation process from singlet states with a time constant of about 3 ns while the ER S1 is dominated by the de-excitation process from triplet states with a time constant of about 24 ns. As the size of the detectors increases, the variation in the S1 photon flight path can become comparable to these decay constants, reducing the utility of pulse-shape analysis to separate NR from ER. The effect of path length variations in the LUX detector has been studied using the results of simulations and the impact on the S1 pulse shape analysis is discussed.

  7. Reactor neutron activation analysis of industrial materials

    International Nuclear Information System (INIS)

    The specific application of neutron activation analysis (n.a.a.) for industrial materials is demonstrated by the determination of impurities in BeO, Al, Si, Cu, Ge, GaP, GaAs, steel, and irradiated uranium. A group scheme gives an orientation about the possibilities of n.a.a. The use of different standards, methods for the measurement of low radioactivities and errors caused by recoil reaction and radiation stimulated diffusion are discussed. (author)

  8. Development of prompt gamma activation analysis

    International Nuclear Information System (INIS)

    Application of prompt gamma-activation analysis to some environmental samples and NBS's standard reference materials were examined, using NBS reactor and the technique developed by the nuclear chemistry group of the University of Maryland. Concentration of several elements, Cd, B, S, Se, Sb, Zn, Ba, Cr, Cs, Co, Si, Hf, Ce, Yb, Lu, Th, Sc, Eu, Fe, Ta and Rb, were determined by both PGAA and INAA. (author)

  9. Target-Activated Modulation of Dual-Color and Two-Photon Fluorescence of Graphene Quantum Dots for in Vivo Imaging of Hydrogen Peroxide.

    Science.gov (United States)

    Zhao, Wenjie; Li, Yinhui; Yang, Sheng; Chen, Yun; Zheng, Jing; Liu, Changhui; Qing, Zhihe; Li, Jishan; Yang, Ronghua

    2016-05-01

    The development of nanoprobes suitable for two-photon microscopy techniques is highly desirable for mapping biological species in living systems. However, at the current stage, the nanoprobes are restricted to single-color fluorescence changes, making it unsuitable for quantitative detection. To circumvent this problem, we report here a rational design of a dual-emission and two-photon (TP) graphene quantum dot (GQD(420)) probe for imaging of hydrogen peroxide (H2O2). For specific recognition of H2O2 and lighting the fluorescence of TPGQD(420), a boronate ester-functionalized merocyanine (BMC) fluorophore was used as both target-activated trigger and the dual-emission fluorescence modulator. Upon two-photon excitation at 740 nm, TPGQD(420)-BMC displays a green-to-blue resolved emission band in response to H2O2 with an emission shift of 110 nm, and the H2O2 can be determined from 0.2 to 40 μM with a detection limit of 0.05 μM. Moreover, the fluorescence response of the TPGQD(420)-BMC toward H2O2 is rapid and extremely specific. The feasibility of the proposed method is demonstrated by two-photon ratiometrically mapping the production of endogenous H2O2 in living cells as well as in deep tissues of murine mode at 0-600 μm. To the best of our knowledge, this is the first paradigm to rationally design a dual-emission and two-photon nanoprobe via fluorescence modulation of GQDs with switchable molecules, which will extend new possibility to design powerful molecular tools for in vivo bioimaging applications. PMID:27072323

  10. Analysis of the relationship between photosynthetic photon flux density and natural Taxus baccata seedlings occurrence

    Science.gov (United States)

    Iszkuło, Grzegorz; Boratyński, Adam

    2006-01-01

    The aim of the present work was to analyse the relationship of seedlings and saplings of Taxus baccata to the photosynthetic photon flux density (PPFD) reaching the forest floor under natural conditions. Two permanent plots, subdivided into 1 × 1 m square plots, were established in a naturally regenerating population of T. baccata formed during last decades in the Kórnik Arboretum, Poland. All seedlings in every 1 × 1 m plots were counted. Relative PPFD was measured for every plot at the canopy height of the yew seedlings. The dependence of seedling density upon PPFD was examined. We found, that the frequency of the smallest seedlings (to 6.0 cm tall) was highest in the most shaded plots and decreased in plots with increasing PPFD. Thus, the youngest yew seedlings can germinate and grow in very shady conditions. However, the older seedlings (6.1-25.0 and 25.1-100.0 classes) were observed most frequently in 2-7% PPFD. The small numbers of older, taller seedlings in deep shade likely indicate a higher mortality rate of seedlings less than 6 cm in height without promotion to the next height class. Probably the low value of PPFD under the canopy of the stand significantly reduces the competition of other plants with the youngest yew seedlings. At higher light levels they may not be able to compete with more light-demanding plants, such as herbs and seedlings of broad-leaved trees. The seedlings of the second (6.1-25.0 cm) and third (25.1-100.0 cm) height classes were observed most frequently in the plots with 2-7% PPFD ( Fig. 1b and c).

  11. Activation Analysis and Public Health. Survey Paper

    International Nuclear Information System (INIS)

    The technique of activation analysis has useful and distinctive applications, not yet fully recognized or exploited, in public health. Three areas of usefulness may be recognized. 1. Industrial hygiene. Activation analysis offers a simple and efficient method for assessing and controlling occupational hazards associated with the handling of toxic materials, such as compounds of arsenic and of mercury. Examination of hair and nail samples, taken at six-monthly intervals, will yield a surprising amount of information regarding the influence on occupational exposure of individual variation in working habits, and inadequacy or non-observance of hygienic rules and other prescribed safety measures. 2. Epidemiology. The advantage conferred by activation analysis lies in the possibility of rapid and accurate estimation of trace element concentrations in small samples of tissue or other materials, such as can readily be obtained from population groups large enough to be statistically significant. Surveys of this kind have interesting potentialities in relation to dental caries, cancer, cirrhosis of the liver and heart disease. 3. Recognition of essential trace elements. Surveys of trace element concentrations suggest that the variability of tissue levels among members of a population is smaller for essential trace elements than for non-essential elements. It is possible also that tissue levels show a normal distribution for essential elements and a log-normal distribution for non-essential elements. (author)

  12. Two-photon processes in highly charged ions

    International Nuclear Information System (INIS)

    Two-photon processes are atomic processes in which an atom interacts simultaneously with two photons. Such processes describe a wide range of phenomena, such as two-photon decay and elastic or inelastic scattering of photons. In recent years two-photon processes involving highly charged heavy ions have become an active area of research. Such studies do not only consider the total transition or scattering rates but also their angular and polarization dependence. To support such examinations in this thesis I present a theoretical framework to describe these properties in all two-photon processes with bound initial and final states and involving heavy H-like or He-like ions. I demonstrate how this framework can be used in some detailed studies of different two-photon processes. Specifically a detailed analysis of two-photon decay of H-like and He-like ions in strong external electromagnetic fields shows the importance of considering the effect of such fields for the physics of such systems. Furthermore I studied the elastic Rayleigh as well as inelastic Raman scattering by heavy H-like ions. I found a number of previously unobserved phenomena in the angular and polarization dependence of the scattering cross-sections that do not only allow to study interesting details of the electronic structure of the ion but might also be useful for the measurement of weak physical effects in such systems.

  13. Two-photon processes in highly charged ions

    Energy Technology Data Exchange (ETDEWEB)

    Jahrsetz, Thorsten

    2015-03-05

    Two-photon processes are atomic processes in which an atom interacts simultaneously with two photons. Such processes describe a wide range of phenomena, such as two-photon decay and elastic or inelastic scattering of photons. In recent years two-photon processes involving highly charged heavy ions have become an active area of research. Such studies do not only consider the total transition or scattering rates but also their angular and polarization dependence. To support such examinations in this thesis I present a theoretical framework to describe these properties in all two-photon processes with bound initial and final states and involving heavy H-like or He-like ions. I demonstrate how this framework can be used in some detailed studies of different two-photon processes. Specifically a detailed analysis of two-photon decay of H-like and He-like ions in strong external electromagnetic fields shows the importance of considering the effect of such fields for the physics of such systems. Furthermore I studied the elastic Rayleigh as well as inelastic Raman scattering by heavy H-like ions. I found a number of previously unobserved phenomena in the angular and polarization dependence of the scattering cross-sections that do not only allow to study interesting details of the electronic structure of the ion but might also be useful for the measurement of weak physical effects in such systems.

  14. Degeneracy analysis for a super cell of a photonic crystal and its application to the creation of band gaps

    OpenAIRE

    Wu, Liang; He, Sailing

    2002-01-01

    A method is introduced to analyze the degeneracy properties of the band structure of a photonic crystal making use of the super cells. The band structure associated with a super cell of a photonic crystal has degeneracies at the edge of the Brillouin zone if the photonic crystal has some kind of point group symmetry. Both E-polarization and H-polarization cases have the same degeneracies for a 2-dimensional (2D) photonic crystal. Two theorems are given and proved. These degeneracies can be li...

  15. Neutron Activation analysis of waste water

    International Nuclear Information System (INIS)

    An instrumental neutron activation analysis for the simultaneous determination of chlorine, bromine, sodium, manganese, cobalt, copper, chromium, zinc, nickel, antimony and iron in waste water is described. They were determined in waste water samples under normal conditions by non-destructive neutron activation simultaneously using a suitable monostandard method. Standardized water samples were used and irradiated in polyethylene ampoules at a neutron flux of 1013 cm-2 s-1 for periods of 1 minute, 1 and 10 hours. A Ge hyperpure detector was used for your activity determination, with count times of 60, 180, 300 and 600 seconds. The obtained results show than the method can be utilized for the determination of this elements without realize anything previous treatment of the samples. (Author)

  16. Nuclear data for proton activation analysis

    International Nuclear Information System (INIS)

    The activation analysis with charged particles (ChPAA), as well as proton activation analysis (PAA), mainly requires separately irradiation of thick (thicker than the range of particles) samples and standard. Therefore for simplicity of determination of traces of chemical elements by instrumental PAA the absolute activity of the radionuclides must be known. Consequently we compilated data for nuclear decays (half life, radiation energy and intensity, type of decay, saturation factor), for nuclear reactions (excitation function, threshold energy, Q-value, yields of radionuclides), for the element under study (natural isotopic abundance of the nuclide, which yields the nuclear reaction considered, molar mass), stopping power of the irradiated material and the range of the particle that are used in the calculation of the absolute activity of the radionuclides and for the resolution of a nuclear interference problems of PAA. These data are tabulated. The tables of the radionuclides are presented in dependence on increasing atomic number and radiation energy as well as on methods of the radionuclide formation. The thick target yields of analytical radionuclides are presented versus particle energy

  17. Instrumental neutron activation analysis of soil sample

    International Nuclear Information System (INIS)

    This paper describes the analysis of soil samples collected from 5 different location around Sungai Lui, Kajang, Selangor, Malaysia. These sample were taken at 22-24 cm from the top of the ground and were analysed using the techniques of Instrumental Neutron Activation Analysis (INAA). The analysis on soil sample taken above 22-24 cm level were done in order to determine if there is any variation in elemental contents at different sampling levels. The results indicate a wide variation in the contents of the samples. About 30 elements have been analysed. The major ones are Na, I, Cl, Mg, Al, K, Ti, Ca and Fe. Trace elements analysed were Ba, Sc, V, Cr, Mn, Ga, As, Zn, Br, Rb, Co, Hf, Zr, Th, U, Sb, Cs, Ce, Sm, Eu, Tb, Dy, Yb, Lu and La. (author)

  18. Neutron activation analysis of geological materials

    International Nuclear Information System (INIS)

    Neutron activation analysis (NAA) is an extremely sensitive, selective and precise method, which yields a wealth of elemental information from even a small-sized sample. With the recent advances in nuclear reactors and high-efficiency and high-resolution semiconductor detectors, NAA has become a powerful method for multielemental analysis. The concentration of major, minor, and trace elements vary from 1 to 4 orders of magnitude in geological materials. By varying neutron fluxes, irradiation times, decay and counting intervals and using both instrumental and radiochemical techniques in NAA, it is possible to accurately determine about 50 elements in a sample aliquant. The practical aspects of the NAA method as applied to geological materials are discussed in detail, and are demonstrated by the analysis of the United States Geological Survey (USGS) and the International Atomic Energy Agency (IAEA) standard reference geological materials. General aspects of the elemental interpretations in terrestrial samples are also discussed. (author)

  19. Analysis of ayurvedic medicinal leaves by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    Concentrations of 15 elements were determined in medicinally important ayurvedic medicinal leaves. Instrumental neutron activation analysis was employed for the determination of the elements viz. Na, K, Br, Sm, Cr, Zn, Th, Rb, Sr, Fe, La, Co, Ce, Cs and Eu. The samples were neutron irradiated at 100 kW TRIGA -Mainz nuclear reactor and the induced activities were measured by gamma ray spectrometry using an efficiency calibrated high resolution high purity germanium (HPGe) detector. The concentrations of these elements in the medicinal leaves and their medicinal importance are discussed. (author)

  20. Multielemental analysis of soils by instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    The results of an instrumental neutron activation analysis of some elemental concentrations in different soil samples near the industrial areas at Tirupati, India, are reported. Altogether 14 elements, Sm, La, Cr, Co, Zn, Cs, Ce, Th, Rb, Na, K, Sr, Fe and Eu were determined. The samples were irradiated with neutrons at the 100 kW Triga - Mainz research reactor and the induced activities were measured by gamma-ray spectrometry using an efficiency calibrated high resolution high purity germanium (HPGe) detector in connection with a multichannel analyzer. The results are discussed. (author)

  1. Analysis of a photon number resolving detector based on fluorescence readout of an ion Coulomb crystal quantum memory inside an optical cavity

    DEFF Research Database (Denmark)

    Clausen, Christoph; Sangouard, N.; Drewsen, M.

    2013-01-01

    larger than 93%. Moderate experimental parameters allow for repetition rates of about 3 kHz, limited by the time needed for fluorescence collection and re-cooling of the ions between trials. Our analysis may lead to the first implementation of a photon number resolving detector in atomic ensembles.......-efficiency photon counting in large ensembles of atoms. The large number of atoms can, however, pose significant problems in terms of noise stemming from imperfect initial state preparation and off-resonant fluorescence. We identify and analyse a concrete implementation of a photon number resolving detector based...... on an ion Coulomb crystal inside a moderately high-finesse optical cavity. The cavity enhancement leads to an effective optical depth of 15 for a finesse of 3000 with only about 1500 ions interacting with the light field. We show that these values allow for essentially noiseless detection with an efficiency...

  2. Large sample activation analysis. Monitoring of photovoltaic module recycling using radioanalytical methods

    International Nuclear Information System (INIS)

    Photovoltaic modules are the most promising sources of renewable energy. According to respective EU Directives both the glass carrier material and the photo-active layer (CdTe in this study) shall be re-used. Analyses for process surveillance and control have to be carried out, primarily for monitoring of the separation efficiency and the enrichment level of CdTe. For on-site measurement and process control energy-dispersive X-ray fluorescence spectrometry was used. Instrumental photon activation analysis using an electron linear accelerator as activating bremsstrahlung source is intended to be used later for iterative intermediate analysis of random samples for quality control. In this work, the feasibility of both methods for this task was studied. (author)

  3. Innovative Concepts in Microwave Photonics

    OpenAIRE

    Capmany Francoy, José; Sales Maicas, Salvador; Gasulla Mestre, Ivana; Mora Almerich, José; Lloret Soler, Juan Antonio; Sancho Durá, Juan

    2012-01-01

    This paper reports the work carried by ITEAM researchers on novel concepts in the field of Microwave Photonics (MWP). It includes activities related to the general modelling of MWP systems, the use of novel multicore fibers and recent advances in the emergent and hot topic of integrated microwave photonics. Capmany Francoy, J.; Sales Maicas, S.; Gasulla Mestre, I.; Mora Almerich, J.; Lloret Soler, JA.; Sancho Durá, J. (2012). Innovative Concepts in Microwave Photonics. Waves...

  4. Dosimetric analysis for photon and electron beams in Whole body irradiation

    International Nuclear Information System (INIS)

    To initiate the Whole body irradiation as an alternative for the treatment of the hematological diseases, leukemia and assistant for the osseous marrow transplantation, it may be taken account the application of International Protocols about control and quality assurance. It is established the intercomparison by the different dosimetric methods: cylindrical ionization chambers and parallel plane, radiographic emulsion film, semiconductor diodes (Mosfet transistors) and TLD-100 thermoluminescent crystals, obtained measurements for 140 x 140 cm2 fields and large distances 340 cm respect conventional fields in Radiotherapy. The in vitro dosimetry was realized at the Universal Anthropomorphic puppet Alderson Rando basically with the cylindrical crystals (1 mm diameter) of TLD-100 lithium fluoride. It was obtained the dose value with a 0.6 cm3 cylindrical ionization chamber and the Farmer electrometer for Whole body irradiation (ICT) with photons for electrons and were obtained values with the Markus plane parallel camera. Knowing the dose rate value to the source-surface distance DFS= 80 cm, it was calibrated the crystals with the reference radiation beam of 60 Co for obtaining the response curve: Dose vs. Tl lecture. It was characterized the 10 % of the total population for 300 crystals for applying the statistics corresponding. The luminescence curve obtained of Gaussian form was considered satisfactory by its stability during the pre-anneal lecture and anneal process, getting the main peak lecture at 300 Centigrade according to assigned parameters at lecture equipment TLD Harshaw model 4500. The results indicate the functional dependence with the distance DFS= 340 cm for the following depth PPD, the relations TMR and TPR, the TAR is not calculated by the increment of the dispersion in air. The penumbra increment indicates an increase of the radiation field respect of luminous field. The dispersion angle q1 respect at the field central axis was determined and was

  5. Neutron activation analysis of zirconium niobium alloys

    International Nuclear Information System (INIS)

    Full text: One of the important problems in nuclear reactor projecting is the choice of constructional materials, which meet to the requirements concerned with function, technical characteristics and expected performance of the reactor construction. Also it is necessary to take into account change of their properties under the influence of intensive neutron radiation. Zirconium and zirconium-niobium alloys are used in nuclear engineering as a fuel cladding and both matrix and impurity composition have an influence on their performance capabilities.Under intensive neutron radiation high content of undesirable trace elements in constructional materials can cause forming long-lived radionuclides with high induced activity and hence severe problems may occur at service, control of the equipment and carrying out experiments. Therefore analytical control of component and impurity composition of these materials is an important problem.Neutron activation analysis (NAA) is one of multielemental and high sensitivity methods, which widely applied for the analysis of high purity materials. Prior experiments have shown that instrumental NAA is not suitable for analysis of Zr-Nb alloys due to strong induced matrix activity. Therefore we have developed radiochemical procedure for separation of impurities from matrix elements. Study of the literature data has shown that zirconium and niobium are good extracted from hydrochloric medium by 0 75 M solution of di-2-ethylhexylphosphoric acid (DEHPA) in ortho-xylene. Also this system good extracts hafnium which being accompanying element has high content and interferes with determining impurity elements. To improve separation efficiency we have used 'DEHPA - ZM HCl' chromatography system. On the basis of the carried out researches the radiochemical NAA technique for analysis of high purity zirconium and zirconium-niobium alloys has been developed. The technique is based on extraction-chromatographic separation of matrix radionuclides

  6. The Study of Electromagnetic Wave Propogation in Photonic Crystals Via Planewave Based Transfer (Scattering) Matrix Method with Active Gain Material Applications

    Energy Technology Data Exchange (ETDEWEB)

    Ming LI

    2007-12-01

    In this dissertation, a set of numerical simulation tools are developed under previous work to efficiently and accurately study one-dimensional (1D), two-dimensional(2D), 2D slab and three-dimensional (3D) photonic crystal structures and their defects effects by means of spectrum (transmission, reflection, absorption), band structure (dispersion relation), and electric and/or magnetic fields distribution (mode profiles). Furthermore, the lasing property and spontaneous emission behaviors are studied when active gain materials are presented in the photonic crystal structures. Various physical properties such as resonant cavity quality factor, waveguide loss, propagation group velocity of electromagnetic wave and light-current curve (for lasing devices) can be obtained from the developed software package.

  7. Industrial applications of neutron activation analysis

    International Nuclear Information System (INIS)

    Neutron activation analysis has been widely used in the industry and over the years played a key role in the development of manufacturing process as well as monitoring of the process flow. In this context NAA has been utilized both in R and D, and in the factory as a flexible analytical tool. It has been used successfully in numerous industries including broad categories such as Chemical, Pharmaceutical, Mining, Photographic, Oil and Gas, Automobile, Defense, Semiconductor and Electronic industries. Dow Chemical owns and operates a research reactor for analytical measurements of samples generated in both R and D, and manufacturing area in its plant in Midland, Michigan. Although most industries do not have reactors on their campus but use an off site reactor regularly, and often have in-house neutron sources such as a 252Cf used primarily for NAA. In most industrial materials analysis laboratory NAA is part of a number of analytical techniques such as ICP-MS, AA, SIMS, FTIR, XRF, TXRF etc. Analysis of complex industrial samples may require data from each of these methods to provide a clear picture of the materials issues involved. With the improvement of classical analytical techniques, and the introduction of new techniques, e.g. TXRF, the role of NAA continues to be a key bench mark technique that provides accurate and reliable data. The strength of the NAA in bulk analysis is balanced by its weakness in providing surface sensitive or spatially resolved analysis as is required by many applications. (author)

  8. Photon Stars

    OpenAIRE

    Schmidt, H. -J.; Homann, F.

    1999-01-01

    We discuss numerical solutions of Einstein's field equation describing static, spherically symmetric conglomerations of a photon gas. These equations imply a back reaction of the metric on the energy density of the photon gas according to Tolman's equation. The 3-fold of solutions corresponds to a class of physically different solutions which is parameterized by only two quantities, e.g. mass and surface temperature. The energy density is typically concentrated on a shell because the center c...

  9. Photonic Nanojets

    OpenAIRE

    Heifetz, Alexander; Kong, Soon-Cheol; Alan V. Sahakian; Taflove, Allen; Backman, Vadim

    2009-01-01

    This paper reviews the substantial body of literature emerging since 2004 concerning photonic nanojets. The photonic nanojet is a narrow, high-intensity, non-evanescent light beam that can propagate over a distance longer than the wavelength λ after emerging from the shadow-side surface of an illuminated lossless dielectric microcylinder or microsphere of diameter larger than λ. The nanojet’s minimum beamwidth can be smaller than the classical diffraction limit, in fact as small as ~λ/3 for m...

  10. Microwave photonics

    CERN Document Server

    Lee, Chi H

    2013-01-01

    Microwave photonics continues to see rapid growth. The integration of optical fiber and wireless networks has become a commercial reality and is becoming increasingly pervasive. Such hybrid technology will lead to many innovative applications, including backhaul solutions for mobile networks and ultrabroadband wireless networks that can provide users with very high bandwidth services. Microwave Photonics, Second Edition systematically introduces important technologies and applications in this emerging field. It also reviews recent advances in micro- and millimeter-wavelength and terahertz-freq

  11. Germanium for silicon photonics

    Energy Technology Data Exchange (ETDEWEB)

    Ishikawa, Yasuhiko, E-mail: y-ishikawa@material.t.u-tokyo.ac.j [Department of Materials Engineering, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan); Wada, Kazumi [Department of Materials Engineering, Graduate School of Engineering, University of Tokyo, 7-3-1 Hongo, Bunkyo, Tokyo 113-8656 (Japan)

    2010-01-01

    This paper describes that Ge plays an enabler to integrate active photonic devices on a Si platform. In spite of the large lattice mismatch of {approx} 4% between Ge and Si, high-quality Ge layers can be epitaxially grown on Si by ultrahigh-vacuum chemical vapor deposition. Applications of the Ge layers to near-infrared active photonic devices, i.e., photodiodes, optical modulators and light emitters, are described. Several issues on the device physics as well as the integration with Si electronics are discussed.

  12. Optimization of time characteristics in activation analysis

    International Nuclear Information System (INIS)

    Full text: The activation analysis temporal characteristics optimization methods developed at present are aimed at determination of optimal values of the three important parameters - irradiation time, cooling time and measurement time. In the performed works, especially in [1-5] the activation analysis processes are described, the optimal values of optimization parameters are obtained from equations solved, and the computational results are given for these parameters for a number of elements. However, the equations presented in [2] were inaccurate, did not allow one to have optimization parameters results for one element content calculations, and it did not take into account background dependence of time. Therefore, we proposed modified equations to determine the optimal temporal parameters and iteration processes for the solution of these equations. It is well-known that the activity of studied sample during measurements does not change significantly, i.e. measurement time is much shorter than the half-life, thus the processes taking place can be described by the Poisson probability distribution, and in general case one can apply binomial distribution. The equation and iteration processes use in this research describe both probability distributions. Expectedly, the cooling time iteration expressions obtained for one element analysis case are similar for the both distribution types, as the optimised time values occurred to be of the same order as half-life values, whereas the cooling time, as we observed, depends on the ratio of the studied sample's peak value to the background peak, and can be significantly larger than the half-life value. This pattern is general, and can be derived from the optimized time expressions, which is supported by the experimental data on short-living isotopes [3,4]. For the isotopes with large half-lives, up to years, like cobalt-60, the cooling time values given in the above mentioned works are equal to months which, apparently

  13. Mesoscopic photon heat transistor

    DEFF Research Database (Denmark)

    Ojanen, T.; Jauho, Antti-Pekka

    2008-01-01

    We show that the heat transport between two bodies, mediated by electromagnetic fluctuations, can be controlled with an intermediate quantum circuit-leading to the device concept of a mesoscopic photon heat transistor (MPHT). Our theoretical analysis is based on a novel Meir-Wingreen-Landauer-typ......We show that the heat transport between two bodies, mediated by electromagnetic fluctuations, can be controlled with an intermediate quantum circuit-leading to the device concept of a mesoscopic photon heat transistor (MPHT). Our theoretical analysis is based on a novel Meir...

  14. Selective photo-activation analysis with laser-driven x-rays

    Science.gov (United States)

    Banerjee, Sudeep; Golovin, Grigory; Powers, Nathan; Liu, Cheng; Chen, Shouyuan; Petersen, Chad; Zhang, Jun; Ghebregziabher, Isaac; Zhao, Baozhen; Brown, Kevin; Mills, Jared; Umstadter, Donald; Haden, Dan; Silano, Jack; Karwowski, Hugon

    2013-04-01

    We discuss a technique for the identification of nuclear isotopes by selective photo-activation analysis. A narrow divergence beam of high-energy photons is produced when a laser driven electron beam Compton backscatters off a counter-propagating high-intensity laser pulse. The x-rays from this compact laser-driven synchrotron light source are MeV energy, narrow-bandwidth, tunable, polarized, and bright (10^8 photons s-1). Such characteristics make these x-rays well-suited for nuclear interrogation by means of triggering (γ,f) and (γ,xn) reactions. The narrow bandwidth of the x-ray light can be exploited to selectively activate nuclei with isotopic sensitivity, without causing unwanted background from collateral activation. Additionally, the polarized nature of the x-rays can be used to study anisotropy of neutron emission, for precise identification of isotopes. Activation by laser-driven synchrotron x-rays will be compared with activation by bremsstrahlung.

  15. Scalable histopathological image analysis via active learning.

    Science.gov (United States)

    Zhu, Yan; Zhang, Shaoting; Liu, Wei; Metaxas, Dimitris N

    2014-01-01

    Training an effective and scalable system for medical image analysis usually requires a large amount of labeled data, which incurs a tremendous annotation burden for pathologists. Recent progress in active learning can alleviate this issue, leading to a great reduction on the labeling cost without sacrificing the predicting accuracy too much. However, most existing active learning methods disregard the "structured information" that may exist in medical images (e.g., data from individual patients), and make a simplifying assumption that unlabeled data is independently and identically distributed. Both may not be suitable for real-world medical images. In this paper, we propose a novel batch-mode active learning method which explores and leverages such structured information in annotations of medical images to enforce diversity among the selected data, therefore maximizing the information gain. We formulate the active learning problem as an adaptive submodular function maximization problem subject to a partition matroid constraint, and further present an efficient greedy algorithm to achieve a good solution with a theoretically proven bound. We demonstrate the efficacy of our algorithm on thousands of histopathological images of breast microscopic tissues. PMID:25320821

  16. Light-Front Quark Model Analysis of Meson-Photon Transition Form Factor

    Science.gov (United States)

    Choi, Ho-Meoyng; Ji, Chueng-Ryong

    2016-07-01

    We discuss {(π0, η, η') to γ^{*}γ} transition form factors using the light-front quark model. Our discussion includes the analysis of the mixing angles for {η-η'}. Our results for {Q2 F_{(π^0,η,η')toγ^*γ}(Q^2)} show scaling behavior for high Q 2 consistent with pQCD predictions.

  17. Interfacing Dielectric-Loaded Plasmonic and Silicon Photonic Waveguides: Theoretical Analysis and Experimental Demonstration

    DEFF Research Database (Denmark)

    Tsilipakos, O.; Pitilakis, A.; Yioultsis, T. V.; Papaioannou, S.; Vyrsokinos, K.; Kalavrouziotis, D.; Giannoulis, G.; Apostolopoulos, D.; Avramopoulos, H.; Tekin, T.; Baus, M.; Karl, M.; Hassan, K.; Weeber, J. C.; Markey, L.; Dereux, A.; Kumar, A.; Bozhevolnyi, S. I.; Pleros, N.; Kriezis, E. E.

    2012-01-01

    A comprehensive theoretical analysis of end-fire coupling between dielectric-loaded surface plasmon polariton and rib/wire silicon-on-insulator (SOI) waveguides is presented. Simulations are based on the 3-D vector finite element method. The geometrical parameters of the interface are varied in...

  18. Active Shape Analysis of Mandibular Growth

    DEFF Research Database (Denmark)

    Hilger, Klaus Baggesen; Larsen, Rasmus; Kreiborg, Sven;

    2003-01-01

    This work contains a clinical validation using biological landmarks of a Geometry Constrained Diffusion registration of mandibular surfaces. Canonical Correlations Analysis is extended to analyse 3D landmarks and the correlations are used as similarity measures for landmark clustering. A novel...... Active Shape Model is proposed targeting growth modelling by applying Partial Least Squares regression in decomposing the Procrustes tangent space. Shape centroid size is applied as dependent variable but the method generalizes to handle other, both uni- and multivariate, effects probing for high...

  19. Activation Analysis and Nuclear Research in Burma

    International Nuclear Information System (INIS)

    Research endeavours in the field of Nuclear Sciences in Burma appear to be concentrated in three main Institutions. These are the Chemistry and Physics Departments of the Rangoon Arts & Science University and the Union of Burma Applied Research Institute (UBARI). In view of possible forthcoming developments an expanded research programme, which is to be implemented on the basis of a five year plan, has been drawn up. Research topics included in this programme are predominantly of practical interest and aimed at a contribution by nuclear methods, in particular activation analysis, to the technological and industrial needs of the country

  20. Toxicological applications of neutron-activation analysis

    International Nuclear Information System (INIS)

    Thermal neutron-activation analysis is recognised as a useful tool for trace element studies in toxicology. This paper describes some recent applications of the technique to three elements when ingested by people in excess of normal intake Two of the elements (copper and chromium) are essential to life and one (bromine) is as yet unclassified. Three deaths were investiagted and trace element levels compared with normal levels from healthy subjects in the same geographical area who had died as a result of violence. (author)

  1. Neutron activation analysis of medicinal plant extracts

    International Nuclear Information System (INIS)

    Instrumental neutron activation analysis was applied to the determination of the elements Br, Ca, Cl, Cs, Fe, K, La, Mg, Mn, Na, Rb and Zn in medicinal extracts obtained from Centella asiatica, Citrus aurantium L., Achyrolcline satureoides DC, Casearia sylvestris, Solano lycocarpum, Zingiber officinale Roscoe, Solidago microglossa and Stryphnondedron barbatiman plants. The elements Hg and Se were determined using radiochemical separation by means of retention of Se in HMD inorganic exchanger and solvent extraction of Hg by bismuth diethyldithiocarbamate solution. Precision and accuracy of the results were evaluated by analyzing biological reference materials. The therapeutic action of some elements found in plant extracts analyzed is briefly discussed. (author). 15 refs., 5 tabs

  2. Support system for Neutron Activation Analysis

    International Nuclear Information System (INIS)

    In the research reactor of JAERI, the Neutron Activation Analysis (NAA) has been utilized as a major part of an irradiation usage. To utilize NAA, research participants are always required to learn necessary technique. Therefore, we started to examine a support system that will enable to carry out INAA easily even by beginners. The system is composed of irradiation device, gamma-ray spectrometer and data analyzing instruments. The element concentration is calculated by using KAYZERO/SOLCOI software with the K0 standardization method. In this paper, we review on a construction of this INAA support system in JRR-3M of JAERI. (author)

  3. Activation analysis for food chemistry Pt. 3

    International Nuclear Information System (INIS)

    The nondestructive determination of K, Na, Ca, Mg, Cl and P content of animal tissues was reported. The IBR-30 (Dubna) reactor was used as the thermal neutron source for all the (n,ν) reactions needed for the analyses (tabulated), and as the source of fast neutrons for the (n,α) reaction of the P determination, too. Results and errors of the analyses (5-15%) were discussed comparing the reproducibility of the methods in case of different animal tissues, liver, bones, blood, etc. The nondestructive neutron activation multielemental analysis for food chemistry can be recommended in the case of a large scale monitoring program of food samples. (Sz.J.)

  4. Monostandard activation analysis of prehistoric copper objects

    International Nuclear Information System (INIS)

    In order to compare the detection limits of neutron activation analysis and spectral analisys, a number of eneolitic and other copper cultural objects have been investigated. A number of 12 elements could be determined by NAA in a long irradiation run, the same number as in spectral analysis. Six elements have a detection limit an order of magnitude higher than that in spectral analysis and only three have a lower detection limit (Fe, Ni, Sn). If the irradiation time is increased 4 times, only tin remains with a lower detection limit. Other three elements (Hg, Cs, Se), which were not reported in spectral analysis, can be seen with high sensitivity. An average counting time of 1 hour seems to be enough for a satisfactory statistics. No chemical processing of the sample is needed, except a slight etching and washing before or after irradiation. It is concluded that monostandard NAA is a rather simple and reliable method with a higher sensitivity compared to the spectral method

  5. Polarization properties of photonic bandgap fibers

    DEFF Research Database (Denmark)

    Broeng, Jes; Libori, Stig E. Barkou; Bjarklev, Anders Overgaard

    2000-01-01

    We present the first analysis of polarization properties of photonic bandgap fibers. Strong birefringence may be obtained for modest non-uniformities in and around the core region, suggesting the use of photonic bandgap fibers as polarization maintaining components.......We present the first analysis of polarization properties of photonic bandgap fibers. Strong birefringence may be obtained for modest non-uniformities in and around the core region, suggesting the use of photonic bandgap fibers as polarization maintaining components....

  6. Single-Photon Technologies Based on Quantum-Dots in Photonic Crystals

    DEFF Research Database (Denmark)

    Lehmann, Tau Bernstorff

    In this thesis, the application of semiconductor quantum-dots in photonic crystals is explored as aresource for single-photon technology.Two platforms based on photonic crystals, a cavity and a waveguide, are examined as platformssingle-photon sources. Both platforms demonstrate strong single-photon...... purity under quasi-resonantexcitation. Furthermore the waveguide based platform demonstrates indistinguishable single-photonsat timescales up to 13 ns.A setup for active demultiplexing of single-photons to a three-fold single-photon state is proposed.Using a fast electro-optical modulator, single-photons...... from a quantum-dot are routed on timescalesof the exciton lifetime. Using active demultiplexing a three-fold single-photon state is generated at anextracted rate of 2:03 ±0:49 Hz.An on-chip power divider integrated with a quantum-dot is investigated. Correlation measurementof the photon statistic...

  7. All-photonic quantum repeaters.

    Science.gov (United States)

    Azuma, Koji; Tamaki, Kiyoshi; Lo, Hoi-Kwong

    2015-01-01

    Quantum communication holds promise for unconditionally secure transmission of secret messages and faithful transfer of unknown quantum states. Photons appear to be the medium of choice for quantum communication. Owing to photon losses, robust quantum communication over long lossy channels requires quantum repeaters. It is widely believed that a necessary and highly demanding requirement for quantum repeaters is the existence of matter quantum memories. Here we show that such a requirement is, in fact, unnecessary by introducing the concept of all-photonic quantum repeaters based on flying qubits. In particular, we present a protocol based on photonic cluster-state machine guns and a loss-tolerant measurement equipped with local high-speed active feedforwards. We show that, with such all-photonic quantum repeaters, the communication efficiency scales polynomially with the channel distance. Our result paves a new route towards quantum repeaters with efficient single-photon sources rather than matter quantum memories. PMID:25873153

  8. Eta photoproduction in a combined analysis of pion- and photon-induced reactions

    International Nuclear Information System (INIS)

    The ηN final state is isospin-selective and thus provides access to the spectrum of excited nucleons without being affected by excited Δ states. To this end, the world database on eta photoproduction off the proton up to a center-of-mass energy of E ∝ 2.3 GeV is analyzed, including data on differential cross sections, and single- and double-polarization observables. The resonance spectrum and its properties are determined in a combined analysis of eta and pion photoproduction off the proton together with the reactions πN → πN, ηN, KΛ and KΣ. For the analysis, the so-called Juelich coupled-channel framework is used, incorporating unitarity, analyticity, and effective three-body channels. Parameters tied to photoproduction and hadronic interactions are varied simultaneously. The influence of recent MAMI T and F asymmetry data on the eta photoproduction amplitude is discussed in detail. (orig.)

  9. Rotational State Analysis of AlH$^+$ by Two-Photon Dissociation

    CERN Document Server

    Seck, Christopher M; Lien, Chien-Yu; Stollenwerk, Patrick R; Odom, Brian C

    2014-01-01

    We perform \\textit{ab initio} calculations needed to predict the cross-section of an experimentally accessible ($1+1'$) resonance-enhanced multiphoton dissociation (REMPD) pathway in AlH$^+$. Experimenting on AlH$^+$ ions held in a radiofrequency Paul trap, we confirm dissociation via this channel with analysis performed using time-of-flight mass spectrometry. We demonstrate the use of REMPD for rotational state analysis, and we measure the rotational distribution of trapped AlH$^+$ to be consistent with the expected thermal distribution. AlH$^+$ is a particularly interesting species for ion trap work because of its electronic level structure, which makes it amenable to proposals for rotational optical pumping, direct Doppler cooling, and single-molecule fluorescence detection. Potential applications of trapped AlH$^+$ include searches for time-varying constants, quantum information processing, and ultracold chemistry studies.

  10. Microprocessor-based scan control unit for electron and photon beams used in surface analysis

    Energy Technology Data Exchange (ETDEWEB)

    Haney, S.J.

    1979-05-01

    A microprocessor-based X-Y scan control unit was developed to interface with existing PHI Scanning Auger Microprobe and exoelectron emission electronics. The unit provides precise and versatile control of the rastered beams used for surface analysis. In addition to manual control there are options for automatic line and area scans with up to 1000 discrete beam analysis points per line (up to 10/sup 6/ for an entire frame area) and scanning rates continuously adjustable from 1 to 2000 points per second. The design of the unit is such that it can be used in a variety of applications requiring accurate X-Y position control. This report gives a complete description of the scanning control unit's operating controls, internal programming, and circuitry.

  11. Sensitivity analysis and benchmarking of low and broad energy photon measurements for spent nuclear fuel

    International Nuclear Information System (INIS)

    While gamma measurements are a well understood technique for estimating burn up and cooling time in spent nuclear fuel, only a few isotopes are currently used and calculations are dependent on operator declarations. Utilizing a larger set of nuclide measurements as well as including low energy measurements (around 100 keV) could provide a significant increase in the information gained from such measurements. Nuclides investigated in this work include 235U, 238U, 239Pu, 240Pu, 137Cs, 154Eu, 241Am, 155Eu, 149Sm, and 155Gd. Low energy, broad range, and high energy gamma measurements have been performed on a variety of spent uranium dioxide and MOX fuel from PWRs. Selected measured fuel locations have been simulated with Origen, TransLAT, SCALE, and Monteburns to benchmark each of these programs with destructive analysis results. Monteburns was identified as the most accurate program for prediction of isotopes of interest and will be used for future analysis. Origen was chosen as a quick but relatively accurate program to perform a preliminary sensitivity analysis of the effects of fuel parameters (burnup, cooling time, and initial enrichment) on each nuclide measurement. (author)

  12. Fast-neutron activation analysis of light elements

    International Nuclear Information System (INIS)

    Full text: The determination of lithium, carbon, oxygen, nitrogen and other light chemical elements in various modern materials in microgram level is of importance for analytical science. As it is well-known, a thermal neutron activation of C, H, N, and O produces negligible γ-ray activity. 13C (n, γ) 14C and 2H (n, γ) 3H reactions produce very small activities of the non- γ- emitters 3H and 14C, and the 19O (n, γ)19O and 15N(n, γ)16N reactions give very short lived 19O (27 sec) and 16N (7.1 sec). All of these reactions have extremely low thermal neutron cross sections. Therefore a major advantage of the instrumental neutron activation analysis (INAA) is the determination of trace elements in biological, medical and environmental materials. For this reason the above mentioned problems are solved with use of some variants of nuclear analytical techniques based on application of charged particle accelerators. However, there are several non-traditional reactor activation analysis techniques to solve such problems which have been developed and applied in various fields of semiconductor industry, biology, geology. In recent years these techniques were named as the nuclear reactor based charged particles activation analysis (NRCPAA). We distinguished two possible applications of a nuclear reactor as charged particles source. During last years the capabilities of the NRCPAA were investigated intensively and some our results were applied to determine light elements contents [1,2]. The recoil protons are produced as the result of (n, p) elastic and inelastic scattering interaction of fast neutrons with nucleus of light elements, for example, hydrogen. These protons are applied for the development of proton activation analysis for the determination of large concentrations of Li, B and O. The non-destructive activation analysis with use of 14-MeV fast neutrons (FNAA) is the most suitable method for analysis of N, P and Si. FNAA was applied for determination of nitrogen

  13. 14 MeV proton activation analysis

    International Nuclear Information System (INIS)

    A fast nuclear nondestructive method for protein analysis using the 14 MeV proton activation has been developed. The total nitrogen content was measured through the reaction: 14N (p,n) 14O, (Tsub(1/2)=71 s). The 14O activity was detected by means of its characteristic 2.312 MeV gamma-ray line with a NaI(Tl) detector. For a fast determination of a large number of samples a mechanized sistem reacting a rate of one sample per minute has been developed. The laboratory electronics comprises a multichannel analyser, a PDP computer and an electronic module comtroller. Comparison of the results obtained by the method described and the classical Kjeldal technique for samples of various cereal grains (soya bean seads, wheat, barley and corn) showed good correlation. A problem of the analysis of the whole protein region on corn and soya-bean seads, where this region is thicker (0,2 - 2 mm), is mentioned. In this case flour was proposed to be used to obtain a protein homogeneous sample and the irradiaton dose for a sample was about 33,000 Gy, mainly (99%) from protons (27 s x 100 nA x 14 MeV)

  14. Neutron activation analysis of human hair

    International Nuclear Information System (INIS)

    As a part of IAEA research project, ''Activation analysis of hair as an indicator of contamination of man by environmental trace element pollutants'', a survey was carried out to elucidate the levels of various trace element concentration in hair of local population in the Tokyo Metropolitan areas, by applying instrumental neutron activation analysis. A total of 202 scalp hair samples were collected from the inhabitants classified by sex and five age classes. Irradiation was made in the Rikkyo University 100 kW TRIGA MARK-II reactor. Using several combinations of irradiation time, cooling time and counting time, forty elements were determined. The relationship between several trace element contents in hair and such factors as sex, age class, hair treatment, smoking habit and dental treatment, was analyzed by using the method of multiple regression. It was shown that (1) Hair treatment had a predominant effect on the contents of bromine, magnesium and calcium in hair, (2) Aging and amoking contributed increasing mercury content in hair, and hair treatment acted reversely. (author)

  15. Activation Analysis in Forensic Science. Survey Paper

    International Nuclear Information System (INIS)

    Recently the unique features of the activation analysis method have been utilized to advantage to meet some specialized needs in the scientific investigation of crime. A review of the principal forensic activation analysis applications to biological materials to date indicates that they may be roughly classified as: (i) the detection and determination of residues of toxic materials in foodstuffs, human tissues, sera and excreta; (ii) the 'individualization' of hair, fibres, narcotics and drugs; and (iii) investigation of the transference of ballistic material to bone, cloth or paper. Analyses of these materials in some actual forensic investigations have been perfected to the point of acceptance in the law courts of several countries. Additional and broader areas of application are under development in a number of nuclear and forensic laboratories. (i) The determination of sub microgram quantities of phosphorus compounds, arsenic, mercury, selenium and thallium in specimens from post-mortem examinations and from living persons showing symptoms of toxicity has revealed certain ingestion of abnormal amount of toxic substances by comparison with similar specimens from healthy persons. In some cases, with tissues such as hair and nails, the time scale of the ingestion of arsenic or mercury has been revealed through the distribution of the deposited element with distance from the growing end or edge. (ii) A series of feasibility studies on the possibility of distinguishing similar materials through their characteristic trace-element patterns have resulted from observations of the wide range or variation in trace impurity content in specimens which come from different individuals or different natural sources. For example, extensive activation analyses for more than twenty elements in human head hair from many people have been carried out and a statistical analysis of the results indicate that activation hair comparisons in forensic investigations may be quite definitive

  16. Analysis of band structure, transmission properties, and dispersion behavior of THz wave in one-dimensional parabolic plasma photonic crystal

    International Nuclear Information System (INIS)

    The photonic band gap of obliquely incident terahertz electromagnetic waves in a one-dimensional plasma photonic crystal is studied. The periodic structure consists of lossless dielectric and inhomogeneous plasma with a parabolic density profile. The dispersion relation and the THz wave transmittance are analyzed based on the electromagnetic equations and transfer matrix method. The dependence of effective plasma frequency and photonic band gap characteristics on dielectric and plasma thickness, plasma density, and incident angle are discussed in detail. A theoretical calculation for effective plasma frequency is presented and compared with numerical results. Results of these two methods are in good agreement

  17. Analysis of band structure, transmission properties, and dispersion behavior of THz wave in one-dimensional parabolic plasma photonic crystal

    Energy Technology Data Exchange (ETDEWEB)

    Askari, Nasim; Eslami, Esmaeil, E-mail: eeslami@iust.ac.ir [Department of Physics, Iran University of Science & Technology, Narmak, Tehran 16846-13114 (Iran, Islamic Republic of); Mirzaie, Reza [Department of Physics, Shahid Beheshti University, G. C., Evin, Tehran 1983969411 (Iran, Islamic Republic of)

    2015-11-15

    The photonic band gap of obliquely incident terahertz electromagnetic waves in a one-dimensional plasma photonic crystal is studied. The periodic structure consists of lossless dielectric and inhomogeneous plasma with a parabolic density profile. The dispersion relation and the THz wave transmittance are analyzed based on the electromagnetic equations and transfer matrix method. The dependence of effective plasma frequency and photonic band gap characteristics on dielectric and plasma thickness, plasma density, and incident angle are discussed in detail. A theoretical calculation for effective plasma frequency is presented and compared with numerical results. Results of these two methods are in good agreement.

  18. Single photon emission computed tomography and statistical parametric mapping analysis in cirrhotic patients with and without minimal hepatic encephalopathy

    International Nuclear Information System (INIS)

    The early diagnosis and treatment of cognitive impairment in cirrhotic patients is needed to improve the patients' daily living. In this study, alterations of regional cerebral blood flow (rCBF) were evaluated in cirrhotic patients using statistical parametric mapping (SPM). The relationships between rCBF and neuropsychological test, severity of disease and biochemical data were also assessed. 99mTc-ethyl cysteinate dimer single photon emission computed tomography was performed in 20 patients with non-alcoholic liver cirrhosis without overt hepatic encephalopathy (HE) and in 20 age-matched healthy subjects. Neuropsychological tests were performed in 16 patients; of these 7 had minimal HE. Regional CBF images were also analyzed in these groups using SPM. On SPM analysis, cirrhotic patients showed regions of significant hypoperfusion in the superior and middle frontal gyri, and inferior parietal lobules compared with the control group. These areas included parts of the premotor and parietal associated areas of the cortex. Among the cirrhotic patients, those with minimal HE had regions of significant hypoperfusion in the cingulate gyri bilaterally as compared with those without minimal HE. Abnormal function in the above regions may account for the relatively selective neuropsychological deficits in the cognitive status of patients with cirrhosis. These findings may be important in the identification and management of cirrhotic patients with minimal HE. (author)

  19. Elemental analysis of ancient potteries using instrumental neutron activation analysis

    International Nuclear Information System (INIS)

    The provenance studies of archaeological artifacts like potteries, bricks, and coins demands elemental analysis. Instrumental Neutron Activation Analysis (INAA) with high resolution gamma ray spectrometry was used due to its high sensitivity and simultaneous multielement capability. The ancient pottery samples belong to Melchittamur, collected from Department of Ancient History, Tamilnadu, were irradiated in KAMINI reactor, IGCAR, Kalpakkam and counted using PC based Aptec MCA card. The peak areas were obtained using peak-fit PHAST software. The elemental concentrations were calculated using relative method with IAEA RM SL-1 as comparator. The concentrations of elements K, Sc, Cr, Mn, Fe, Co, In, Cs, La, Ce, Sm, Eu, Hf and Th were determined. The % uncertainties are within 1-12% except for Cr, In, Cs and Th

  20. Research Activities involving Radioactivation Analysis in Korea

    International Nuclear Information System (INIS)

    When the Triga Mark-II Research Reactor was installed at this institute in 1960, it was furnished with a pneumatic tube, a fume hood, and a laboratory bench for the purpose of developing the utilization of the research reactor in this country. This marked the commencement of research activity in radioactivation analysis in Korea. Since the output of the reactor was not sufficient enough to perform any sophisticated fundamental research work in nuclear science, radioactivation analysis was considered as one of the most promising means of utilising the reactor. Various requests for routine analysis of the trace elements contained in Korean mineral ores, archaeological materials, domestic industrial samples, native medicinal plants, and criminological samples had been filed at this institute. Fortunately, a well trained scientist and technician for the radioactivation work had been working at this division and hence these requests from the public had been well worked out to receive much recognition of scientists and engineers both in this country and overseas. A brief summary of the research work accomplished is presented in this paper and a brief outline of the routine analytical work is also described on the basis of local situations

  1. Real-time analysis, visualization, and steering of microtomography experiments at photon sources

    International Nuclear Information System (INIS)

    A new generation of specialized scientific instruments called synchrotron light sources allow the imaging of materials at very fine scales. However, in contrast to a traditional microscope, interactive use has not previously been possible because of the large amounts of data generated and the considerable computation required translating this data into a useful image. The authors describe a new software architecture that uses high-speed networks and supercomputers to enable quasi-real-time and hence interactive analysis of synchrotron light source data. This architecture uses technologies provided by the Globus computational grid toolkit to allow dynamic creation of a reconstruction pipeline that transfers data from a synchrotron source beamline to a preprocessing station, next to a parallel reconstruction system, and then to multiple visualization stations. Collaborative analysis tools allow multiple users to control data visualization. As a result, local and remote scientists can see and discuss preliminary results just minutes after data collection starts. The implications for more efficient use of this scarce resource and for more effective science appear tremendous

  2. Stimulated photon emission and two-photon Raman scattering in a coupled-cavity QED system

    Science.gov (United States)

    Li, C.; Song, Z.

    2016-01-01

    We study the scattering problem of photon and polariton in a one-dimensional coupled-cavity system. Analytical approximate analysis and numerical simulation show that a photon can stimulate the photon emission from a polariton through polariton-photon collisions. This observation opens the possibility of photon-stimulated transition from insulating to radiative phase in a coupled-cavity QED system. Inversely, we also find that a polariton can be generated by a two-photon Raman scattering process. This paves the way towards single photon storage by the aid of atom-cavity interaction. PMID:26877252

  3. Testing QCD in Photon-Photon Interactions

    OpenAIRE

    Soldner-Rembold, Stefan

    1998-01-01

    At high energies photon-photon interactions are dominated by quantum fluctuations of the photons into fermion-antifermion pairs and into vector mesons. This is called photon structure. Electron-positron collisions at LEP are an ideal laboratory for studying photon structure and for testing QCD.

  4. Implementation of improved interactive image analysis at the Advanced Photon Source (APC) linac

    International Nuclear Information System (INIS)

    An image-analysis system, based on commercially available data visualization software (IDL [1]), allows convenient interaction with image data while still providing calculated beam parameters at a rate of up to 2 Hz. Image data are transferred from the IOC to the workstation via EPICS [2] channel access. A custom EPICS record was created in order to overcome the channel access limit of 16k bytes per array. The user can conveniently calibrate optical transition radiation (OTR) and fluorescent screens, capture background images, acquire and average a series of images, and specify several other filtering and viewing options. The images can be saved in either IDL format or APS-standard format (SDDS [3]), allowing for rapid postprocessing of image data by numerous other software tools

  5. Analysis of computational problems expressing the overall uncertainties: Photons, neutrons and electrons

    International Nuclear Information System (INIS)

    In the frame of the EU Coordination Action CONRAD (coordinated network for radiation dosimetry), WP4 was dedicated to work on computational dosimetry with an action entitled 'Uncertainty assessment in computational dosimetry: an intercomparison of approaches'. Participants attempted one or more of eight problems. This paper presents the results from problems 4-8 - dealing with the overall uncertainty budget estimate; a short overview of each problem is presented together with a discussion of the most significant results and conclusions. The scope of the problems discussed here are: the study of a 137Cs calibration irradiator; the manganese bath technique; the iron sphere experiment using neutron time-of-flight technique; the energy response of a RADFET detector and finally the sensitivity and uncertainty analysis for the recoil-proton telescope discussed in the companion paper. (authors)

  6. Materials analysis using x-ray linear attenuation coefficient measurements at four photon energies

    International Nuclear Information System (INIS)

    The analytical properties of an accurate parameterization scheme for the x-ray linear attenuation coefficient are examined. The parameterization utilizes an additive combination of N compositional- and energy-dependent coefficients. The former were derived from a parameterization of elemental cross-sections using a polynomial in atomic number. The compositional-dependent coefficients are referred to as the mixture parameters, representing the electron density and higher order statistical moments describing elemental distribution. Additivity is an important property of the parameterization, allowing measured x-ray linear attenuation coefficients to be written as linear simultaneous equations, and then solved for the unknown coefficients. The energy-dependent coefficients can be determined by calibration from measurements with materials of known composition. The inverse problem may be utilized for materials analysis, whereby the simultaneous equations represent multi-energy linear attenuation coefficient measurements, and are solved for the mixture parameters. For in vivo studies, the choice of measurement energies is restricted to the diagnostic region (approximately 20 keV to 150 keV), where the parameterization requires N ≥ 4 energies. We identify a mathematical pathology that must be overcome in order to solve the inverse problem in this energy regime. An iterative inversion strategy is presented for materials analysis using four or more measurements, and then tested against real data obtained at energies 32 keV to 66 keV. The results demonstrate that it is possible to recover the electron density to within ±4% and fourth mixture parameter. It is also a key finding that the second and third mixture parameters cannot be recovered, as they are of minor importance in the parameterization at diagnostic x-ray energies

  7. Opportunities in microstructured photonics

    OpenAIRE

    Herzig, Hans Peter; Sfez, Tristan; Scharf, Toralf

    2010-01-01

    The progress in novel light sources, detectors, materials and technology enable new opportunities and challenges for diffractive optics and nanoscale photonics. Important are also analysis tools, such as near-field imaging (SNOM). Only structures that can be characterized can be fabricated

  8. Vesicle Photonics

    Energy Technology Data Exchange (ETDEWEB)

    Vasdekis, Andreas E.; Scott, E. A.; Roke, Sylvie; Hubbell, J. A.; Psaltis, D.

    2013-04-03

    Thin membranes, under appropriate boundary conditions, can self-assemble into vesicles, nanoscale bubbles that encapsulate and hence protect or transport molecular payloads. In this paper, we review the types and applications of light fields interacting with vesicles. By encapsulating light-emitting molecules (e.g. dyes, fluorescent proteins, or quantum dots), vesicles can act as particles and imaging agents. Vesicle imaging can take place also under second harmonic generation from vesicle membrane, as well as employing mass spectrometry. Light fields can also be employed to transport vesicles using optical tweezers (photon momentum) or directly pertrurbe the stability of vesicles and hence trigger the delivery of the encapsulated payload (photon energy).

  9. FDTD analysis of photonic quasicrystals with different tiling geometries and fabrication by single beam computer-generated holography

    CERN Document Server

    Zito, G; Santamato, E; Marino, A; Tkachenko, V; Abbate, G

    2013-01-01

    Multiple-beam holography has been widely used for the realization of photonic quasicrystals with high rotational symmetries not achievable by the conventional periodic crystals. Accurate control of the properties of the interfering beams is necessary to provide photonic band-gap structures. Here we show, by FDTD simulations of the transmission spectra of 8-fold quasiperiodic structures, how the geometric tiling of the structure affects the presence and properties of the photonic band-gap for low refractive index contrasts. Hence, we show an interesting approach to the fabrication of photonic quasicrystals based on the use of a programmable Spatial Light Modulator encoding Computer-Generated Holograms, that permits an accurate control of the writing pattern with almost no limitations in the pattern design. Using this single-beam technique we fabricated quasiperiodic structures with high rotational symmetries and different geometries of the tiling, demonstrating the great versatility of our technique.

  10. Frequency-tunable optoelectronic oscillator using a dual-mode amplified feedback laser as an electrically controlled active microwave photonic filter.

    Science.gov (United States)

    Lu, Dan; Pan, Biwei; Chen, Haibo; Zhao, Lingjuan

    2015-09-15

    A widely tunable optoelectronic oscillator (OEO) based on a self-injection-locked monolithic dual-mode amplified feedback laser (DM-AFL) is proposed and experimentally demonstrated. In the proposed OEO structure, the DM-AFL functions as an active tunable microwave photonic filter (MPF). By tuning the injection current applied on the amplifier section of the AFL, tunable microwave outputs ranging from 32 to 41 GHz and single sideband phase noises below -97  dBc/Hz at 10 kHz offset from the carriers were realized. PMID:26371931

  11. Light coupling between vertical III-As nanowires and planar Si photonic waveguides for the monolithic integration of active optoelectronic devices on a Si platform.

    Science.gov (United States)

    Giuntoni, Ivano; Geelhaar, Lutz; Bruns, Jürgen; Riechert, Henning

    2016-08-01

    We present a new concept for the optical interfacing between vertical III-As nanowires and planar Si waveguides. The nanowires are arranged in a two-dimensional array which forms a grating structure on top of the waveguide. This grating enables light coupling in both directions between the components made from the two different material classes. Numerical simulations show that this concept permits a light extraction efficiency from the waveguide larger than 45% and a light insertion efficiency larger than 35%. This new approach would allow the monolithic integration of nanowire-based active optoelectronics devices, like photodetectors and light sources, on the Si photonics platform. PMID:27505805

  12. Mechanism Analysis of the Inverse Doppler Effect in Two-Dimensional Photonic Crystal based on Phase Evolution

    OpenAIRE

    Qiang Jiang; Jiabi Chen; Yan Wang; Binming Liang; Jinbing Hu; Songlin Zhuang

    2016-01-01

    Although the inverse Doppler effect has been observed experimentally at optical frequencies in photonic crystal with negative effective refractive index, its explanation is based on phenomenological theory rather than a strict theory. Elucidating the physical mechanism underlying the inverse Doppler shift is necessary. In this article, the primary electrical field component in the photonic crystal that leads to negative refraction was extracted, and the phase evolution of the entire process w...

  13. Study and development of a method allowing the identification of actinides inside nuclear waste packages, by active neutron or photon interrogation and delayed gamma-ray spectrometry

    International Nuclear Information System (INIS)

    An accurate estimation of the alpha-activity of a nuclear waste package is necessary to select the best mode of storage. The main purpose of this work is to develop a non-destructive active method, based on the fission process and allowing the identification of actinides (235U, 238U, 239Pu). These three elements are the main alpha emitters contained inside a package. Our technique is based on the detection of delayed gammas emitted by fission products. These latter are created by irradiation with the help of a neutron or photon beam. Performances of this method have been investigated after an Active Photon or Neutron Interrogation (INA or IPA). Three main objectives were fixed in the framework of this thesis. First, we measured many yields of photofission products to compensate the lack of data in the literature. Then, we studied experimental performances of this method to identify a given actinide (239Pu in fission, 235U in photofission) present in an irradiated mixture. Finally, we assessed the application of this technique on different mock-up packages for both types of interrogation (118 l mock-up package containing EVA in fission, 220 l mock-up package with a wall of concrete in photofission). (author)

  14. Numerical analysis of the supercontinuum spectrum generation in a couple of photonic crystal fibers with different structure by using the RK4IP method

    Science.gov (United States)

    Lauterio-Cruz, J. P.; Hernández-García, J. C.; Estudillo-Ayala, J. M.; Pottiez, O.; Rojas-Laguna, R.; Filoteo-Razo, J. D.; Samano-Aguilar, L. F.; Jauregui-Vazquez, D.

    2016-03-01

    In this work, we performed a numerical analysis of the supercontinuum spectrum generation in a couple of photonic crystal fibers with different structure. The proposed configuration initially has an input pulse with hyperbolic secant profile to generate noise-like pulses as output signal, by the Runge-Kutta method (RK4IP). By using the same configuration, now these noise-like pulses are used as pump for supercontinuum generation obtaining a broad and good flatness spectrum. The numerical analysis presented here demonstrates the potential of noise-like pulses from a passively mode-locked fiber laser for broadband spectrum generation combining two different photonic crystal fibers. Besides this paper helps to understand the phenomena of supercontinuum generation which is mainly related to Raman self-frequency shift.

  15. Numerical analysis of In0.53Ga0.47As/InP single photon avalanche diodes

    International Nuclear Information System (INIS)

    A rigorous theoretical model for In0.53Ga0.47As/InP single photon avalanche diode is utilized to investigate the dependences of single photon quantum efficiency and dark count probability on structure and operation condition. In the model, low field impact ionizations in charge and absorption layers are allowed, while avalanche breakdown can occur only in the multiplication layer. The origin of dark counts is discussed and the results indicate that the dominant mechanism that gives rise to dark counts depends on both device structure and operating condition. When the multiplication layer is thicker than a critical thickness or the temperature is higher than a critical value, generation—recombination in the absorption layer is the dominative mechanism; otherwise band-to-band tunneling in the multiplication layer dominates the dark counts. The thicknesses of charge and multiplication layers greatly affect the dark count and the peak single photon quantum efficiency and increasing the multiplication layer width may reduce the dark count probability and increase the peak single photon quantum efficiency. However, when the multiplication layer width exceeds 1 μm, the peak single photon quantum efficiency increases slowly and it is finally saturated at the quantum efficiency of the single photon avalanche diodes. (cross-disciplinary physics and related areas of science and technology)

  16. Neutron activation analysis of urinary calculi

    International Nuclear Information System (INIS)

    Urinary calculi resulting from disorders in the urinary system are mostly composed of uric acid, urates, calcium oxalate, alkaline earth phosphates (Ca and Mg), triple phosphate (magnesium ammonium phosphate), calcium carbonate, cystine, xanthine, and traces of proteins. The determination of these macro-constituents has been carried out by different analytical procedures. No attempts however, have been reported regarding the determination of trace elements in urinary stones, apart from that of Herring et al., who investigated the consumption of strontium by urolithiasis patients. The present work is a non-destructive neutron activation analysis of urinary calculi, to search the variation in concentration of certain trace elements with the chemical composition of the calculus

  17. Reactor neutron activation for multielemental analysis

    International Nuclear Information System (INIS)

    Neutron Activation Analysis using single comparator (K0 NAA method) has been used for obtaining multielemental profiles in a variety of matrices related to environment. Gold was used as the comparator. Neutron flux was characterised by determining f, the epithermal to thermal neutron flux ratio and cc, the deviation from ideal shape of the neutron spectrum. The f and a were determined in different irradiation positions in APSARA reactor, PCF position in CIRUS reactor and tray rod position in Dhruva reactor using both cadmium cut off and multi isotope detector methods. High resolution gamma ray spectrometry was used for radioactive assay of the activation products. This technique is being used for multielement analysis in a variety of matrices like lake sediments, sea nodules and crusts, minerals, leaves, cereals, pulses, leaves, water and soil. Elemental profiles of the sediments corresponding to different depths from Nainital lake were determined and used to understand the history of natural absorption/desorption pattern of the previous 160 years. Ferromanganese crusts from different locations of Indian Ocean were analysed with a view to studying the distribution of some trace elements along with Fe and Mn. Variation of Mn/Fe ratio was used to identify the nature of the crusts as hydrogenous or hydrothermal. Fe-rich and Fe-depleted nodules from Indian Ocean were analysed to understand the REE patterns and it is proposed that REE-Th associated minerals could be the potential Th contributors to the sea water and thus reached ferromanganese nodules. Dolomites (unaltered and altered), two types of serpentines and intrusive rock dolerite from the asbestos mines of Cuddapah basin were analysed for major, minor and trace elements. The elemental concentrations are used for distinguishing and characterising these minerals. From our investigations, it was concluded that both dolomite and dolerite contribute elements in the serpentinisation process. Chemical neutron

  18. Neutron activation analysis of human hair

    International Nuclear Information System (INIS)

    In an attempt to study the availability and limitation of analytical data of human hair as an indicator of environmental pollution and/or of human health effect, concentrations of elements in 202 scalp hair samples collected from local population in the Tokyo Metropolitan area were determined by instrumental neutron activation analysis. The correlation coefficients between concentrations of 13 elements in each sex and in each age group were calculated and discussed. There were significant correlations between some pairs of elements, i.e. Na-K, Br-Cl, Ca-Zn and Ca-Mg, in all five age classes in both of male and female, indicating that the correlations were consistent. Ca was observed to be reversely correlated with Cl. No significant correlation was apparent between Hg and Se, when the correlation coefficient was calculated using logarithmic converted concentration data. (author)

  19. Instrumental neutron activation analysis of kidney stones

    International Nuclear Information System (INIS)

    Kidney stone samples of the types calcium oxalate, uric acid, and xanthine were analyzed for their elemental contents by neutron activation analysis to study both the elemental correlation and influence of element on stone precipitation processes. Elements, such as Al, Au, Br, Ca, Cl, Co, Cr, Fe,H, I, K, Mg, Na, Sb, Se, Sr, and Zn, were determined quantitatively. Calcium oxalate stones contained higher concentration of all the elements analyzed compared to uric acid or xanthine stones. The concentrations of Cl, Fe, K, Na, Sr, and Zn were relatively higher than Au, Co, Cr, and Sb. A positive correlation exists between Ca and Zn, whereas a negative correlation exists between Sr and Ca. Zinc may play an important role in the formation of calcium oxalate stone

  20. Photonic crystals principles and applications

    CERN Document Server

    Gong, Qihuang

    2013-01-01

    IntroductionPrimary Properties of Photonic CrystalsFabrication of Photonic CrystalsPhotonic Crystal All-Optical SwitchingTunable Photonic Crystal FilterPhotonic Crystal LaserPhotonic Crystal Logic DevicesPhotonic Crystal Sensors

  1. Photon Structure in Photon Proton Interactions

    OpenAIRE

    Vossebeld, J. H.

    1998-01-01

    Photoproduction of jets at HERA provides information on the partonic structure of the photon. We report on the latest dijet photoproduction results, for real photons and for photons at low virtualities, measured with the ZEUS detector.

  2. Photon physics with PHENIX

    Energy Technology Data Exchange (ETDEWEB)

    White, S. [Brookhaven National Lab., Upton, NY (United States)

    1995-07-15

    In this Paper the author discusses briefly the physics motivation for extending measurements of particle production with high granularity and particle id capabilities to neutrals in PHENIX. The author then discusses the technique of direct photon measurement in the presence of copious background photons from {pi}{sup o} decays. The experiment will measure relatively low p{sub t} photons near y=0 in the lab frame. This new experimental environment of high multiplicity and low {gamma} momenta will affect both the techniques used and the type of analysis which can be performed. The Phenix Electromagnetic calorimeter is described and its capabilities illustrated with results from simulation and beam tests of the first production array.

  3. Photon Differentials

    DEFF Research Database (Denmark)

    Schjøth, Lars; Frisvad, Jeppe Revall; Erleben, Kenny;

    2007-01-01

    illumination features. This is often not desirable as these may lose clarity or vanish altogether. We present an accurate method for reconstruction of indirect illumination with photon mapping. Instead of reconstructing illumination using classic density estimation on finite points, we use the correlation of...

  4. Photon differentials

    DEFF Research Database (Denmark)

    Schjøth, Lars; Revall Frisvad, Jeppe; Erleben, Kenny;

    2007-01-01

    illumination features. This is often not desirable as these may lose clarity or vanish altogether. We present an accurate method for reconstruction of indirect illumination with photon mapping. Instead of reconstructing illumination using classic density estimation on finite points, we use the correlation of...

  5. Epithermal neutron activation analysis of food

    International Nuclear Information System (INIS)

    Food samples were irradiated with thermal and epithermal neutrons. The average ratios of thermal to epithermal activity were determined for 80Br, 49Ca, 38Cl, 60mCo, 42K, 27Mg, 56Mn, 24Na, and 86mRb. They were equal to 2.1, 26, 24, 6.6, 19, 16, 11, 23 and 1.9, respectively. Then, 57 food samples were analyzed by epithermal neutron activation analysis for Br and Rb. The concentrations (in ppm) of Br and Rb were in asparagus (2) 2.3, 11.5; beets (3) 0.5, 0.8; beef (3) 1.7, 3.6; cabbage (5) 0.5, 10.8; carrot (3) 0.2, 3.7; chicken (3) 0.6, 4.4; chocolate (7) 11.1, 18.7; egg (3) 0.9, 1.9; french bean (3) 0.3, 1.0; goose (2) 1.3, 9.3; lettuce (2) 0.9, 1.7; pork (1) 1.5, 4.4; potato (7) 1.0, 1.2; sausage (3) 4.8, 3.5; spinach (3) 3.6, 4.0; strawberry jam (3) 0.4, 1.4; tomato (1) 13.5, 14.6; turkey (3) 1.2, 4.9. respectively. The number of samples and analyzed is indicated in parentheses. (author)

  6. Neutron activation analysis of arsenic in Greece

    International Nuclear Information System (INIS)

    Arsenic is considered a toxic trace element for plant, animal, and human organisms. Arsenic and certain arsenic compounds have been listed as carcinogens by the U.S. Environmental Protection Agency. Arsenic is emitted in appreciable quantities into the atmosphere by coal combustion and the production of cement. Arsenic enters the aquatic environment through industrial activities such as smelting of metallic ores, metallurgical glassware, and ceramics as well as insecticide production and use. Neutron activation analysis (NAA) is a very sensitive, precise, and accurate method for determining arsenic. This paper is a review of research studies of arsenic in the Greek environment by NAA performed at our radioanalytical laboratory. The objectives of these studies were (a) to determine levels of arsenic concentrations in environmental materials, (b) to pinpoint arsenic pollution sources and estimate the extent of arsenic pollution, and (c) to find out whether edible marine organisms from the gulfs of Greece receiving domestic, industrial, and agricultural wastes have elevated concentrations of arsenic in their tissues that could render them dangerous for human consumption

  7. Solar active regions: a nonparametric statistical analysis

    CERN Document Server

    Pelt, J; Tuominen, I

    2009-01-01

    The sunspots and other solar activity indicators tend to cluster on the surface of the Sun.These clusters very often occur at certain longitudes that persist in time.It is of general interest to find new and simple ways to characterize the observed distributions of different indicators and their behaviour in time. In the present work we use Greenwich sunspot data to evaluate statistical but not totally coherent stability of sunspot distribution along latitudes as well as longitudes. The aim was to obtain information on the longitudinal distribution of the underlying spot-generating mechanism rather than on the distribution and migration of sunspots or sunspot groups on the solar surface. Therefore only sunspot groups were included in the analysis, and only the time of their first appearance was used. We use simple nonparametric approach to reveal sunspot migration patterns and their persistency. Our analysis shows that regions where spots are generated tend to rotate differentially as the spots and spot group...

  8. Applications of neutron activation analysis technique

    International Nuclear Information System (INIS)

    The technique was developed as far back as 1936 by G. Hevesy and H. Levy for the analysis of Dy using an isotopic source. Approximately 40 elements can be analyzed by instrumental neutron activation analysis (INNA) technique with neutrons from a nuclear reactor. By applying radiochemical separation, the number of elements that can be analysed may be increased to almost 70. Compared with other analytical methods used in environmental and industrial research, NAA has some unique features. These are multi-element capability, rapidity, reproducibility of results, complementarity to other methods, freedom from analytical blank and independency of chemical state of elements. There are several types of neutron sources namely: nuclear reactors, accelerator-based and radioisotope-based sources, but nuclear reactors with high fluxes of neutrons from the fission of 235U give the most intense irradiation, and hence the highest available sensitivities for NAA. In this paper, the applications of NAA of socio-economic importance are discussed. The benefits of using NAA and related nuclear techniques for on-line applications in industrial process control are highlighted. A brief description of the NAA set-ups at CERT is enumerated. Finally, NAA is compared with other leading analytical techniques

  9. Quality assurance in neutron activation analysis

    International Nuclear Information System (INIS)

    As a potential reference method, neutron activation analysis does not have to rely on other reference materials to ascertain the quality of analytical results. The fundamental characteristics of the method with the clear separation between irradiation, processing, and counting makes possible the estimation of uncertainties of individual results from a priori assumptions. Such estimates of the standard deviation from a series of independent sources of variation are compared with the a posteriori variability of replicate determinations in order to ascertain that the analytical method is in a state of statistical control. This Analysis of Precision tests the absence of unknown errors by means of a statistic T, which is closely approximated by a chi-square distribution. In this manner an evaluation is made of a commercially available computer program for peak evaluation in γ-spectrometry, as well as of other factors affecting the precision and accuracy of the counting process. An attempt is also made to determine sampling constants of one gram or less in a candidate biological reference material

  10. Epithermal neutron activation analysis in applied microbiology

    International Nuclear Information System (INIS)

    Some results from applying epithermal neutron activation analysis at FLNP JINR, Dubna, Russia, in medical biotechnology, environmental biotechnology and industrial biotechnology are reviewed. In the biomedical experiments biomass from the blue-green alga Spirulina platensis (S. platensis) has been used as a matrix for the development of pharmaceutical substances containing such essential trace elements as selenium, chromium and iodine. The feasibility of target-oriented introduction of these elements into S. platensis biocomplexes retaining its protein composition and natural beneficial properties was shown. The absorption of mercury on growth dynamics of S. platensis and other bacterial strains was observed. Detoxification of Cr and Hg by Arthrobacter globiformis 151B was demonstrated. Microbial synthesis of technologically important silver nanoparticles by the novel actinomycete strain Streptomyces glaucus 71 MD and blue-green alga S. platensis were characterized by a combined use of transmission electron microscopy, scanning electron microscopy and energy-dispersive analysis of X-rays. It was established that the tested actinomycete S. glaucus 71 MD produces silver nanoparticles extracellularly when acted upon by the silver nitrate solution, which offers a great advantage over an intracellular process of synthesis from the point of view of applications. The synthesis of silver nanoparticles by S. platensis proceeded differently under the short-term and long-term silver action. (author)

  11. Applications of neutron activation analysis in chemistry and pollution fields

    International Nuclear Information System (INIS)

    Some examples of applications of activation analysis are given such as: chemical analysis of precious metals, nuclear graphite and hydrocarbons; control of pollution of water and seawater, analysis of food and seafood, atmospheric, dust and hair for determination of impurities

  12. Two-order Interference of Single Photon

    Institute of Scientific and Technical Information of China (English)

    JIANG Yunkun; LI Jian; SHI Baosen; FAN Xiaofeng; GUO Guangcan

    2000-01-01

    A pair of photons called signal and idler photons, respectively, are produced through the nonlinear process of type-I spontaneous parametric downconversion in BBO crystal pumped by the second-harmonic wave of a Ti:sapphire femtosecond laser pulse. The two-order interference phenomenon of the signal photon in Michelson interferometer is observed and give an analysis in detail.

  13. Two-Photon Processes and Photon Structure

    OpenAIRE

    Schienbein, I.

    2002-01-01

    In this article aspects of photon-photon physics related to the structure of real and virtual photons are reviewed. A re-calculation of the virtual photon-photon box is performed and some discrepancies in the literature are clarified. A useful compilation of various relevant limits derived from the most general expressions is provided. Furthermore, structure functions of spin-averaged, transverse and longitudinal virtual target photons are defined and discussed. Finally, the factorization of ...

  14. A search for pair halos around active galactic nuclei through a temporal analysis of Fermi-LAT data

    CERN Document Server

    Prokhorov, D A

    2015-01-01

    We develop a method to search for pair halos around active galactic nuclei (AGN) through a temporal analysis of gamma-ray data. The basis of our method is an analysis of the spatial distributions of photons coming from AGN flares and from AGN quiescent states and a further comparison of these two spatial distributions. This method can also be used for a reconstruction of a point spread function (PSF). We found no evidence for a pair halo component through this method by applying it to the Fermi-LAT data in the energy bands of 4.5-6, 6-10, and >10 GeV and set upper limits on the fraction of photons attributable to a pair halo component. An illustration of how to reconstruct the PSF of Fermi-LAT is given.

  15. Dosimetric Comparing between Protons Beam and Photons Beam 
for Lung Cancer Radiotherapy: A Meta-analysis

    Directory of Open Access Journals (Sweden)

    Guangwei TIAN

    2013-05-01

    Full Text Available Background and objective The clinical evidences are not sufficient on the proton beam therapy of lung cancer for lacking of the RCTs on the comparing the proton with the photon beam in lung cancer radiotherapy. The aim of this study is to evaluate the dosimetry superiority of the proton beam and provide more valuable evidences to the clinical researches. Methods Clinical trails of dosimetric comparing between protons beam and photons beam for lung cancer radiotherapy were obtained from the Cochrane library, Pubmed, EMbase, CBM, CNKI, VIP, and Wan Fang databases. The data included in the study were evaluated and analyzed using the Cochrane Collaboration's RevMan 5.2 software. Results Six trails were included. Compared to photon therapy (three-dimensional conformal photon radiotherapy, 3D-CRT, the proton therapy had a significantly lower total lung Dmean (MD=-4.15, 95%CI: -5.56--2.74, P<0.001 and V20, V10, V5 (MD=-10.92, 95%CI: -13.23--8.62, P<0.001; The V20, V10, V5 significantly decreased in proton therapy group. Compared to photon therapy (intensity-modulated photon radiotherapy, IMRT, V20, V10, V5 were also significantly lowered in proton therapy group (MD=-3.70, 95%CI: -5.31--2.10, P<0.001; MD=-8.86, 95%CI: -10.74--6.98, P<0.001; MD=-20.13, 95%CI: -27.11--13.14, P<0.001; The esophagus Dmean was not lowered, while the heart Dmean decreased in proton therapy group. Conclusion Comparing to photon beam radiotherapy (3D-CRT and IMRT, proton beam therapy is advantageous in dosimetry of the lung cancer radiotherapy and recommended for clinical applying.

  16. 7th international conference ''Modern trends in activation analysis''

    International Nuclear Information System (INIS)

    The conference was held on 23-27 June, 1986 in Copenhagen (DK) with the participation of specialists from 42 countries. 175 papers were submitted covering the wide field of applications of neutron activation analysis, from novel techniques to sample preparation, information processes and control, activation techniques, light element and rare earth element determination, ultratracer analysis, quality assurance, comparator methods, and reference materials. The poster session was mainly oriented to industrial applications of activation analysis, biological applications, in vivo use of neutron activation analysis, the applications of neutron activation analysis in environmental control, criminology, etc. (E.S.)

  17. Quantitative mineral salt evaluation in the calcaneous bone using computed tomography, 125I-photon absorption and chemical analysis to compare the value of the individual methods

    International Nuclear Information System (INIS)

    It was the aim of the study described here to verify the accuracy of two different methods for the quantitative evaluation of mineral salts, which were the 125I-photon absorption technique on the one hand and wholebody CT on the other hand. For this purpose, post-mortem examinations of 31 calcaneous bones were carried out to evaluate their individual mineral salt contents in vitro using either of the above-mentioned methods. The results obtained were subsequently contrasted with calcium concentrations determined by chemical analysis. A comparison of the individual mineral salt evaluations with the results from calcium analyses pointed to a highly significant correlation (p=0.001) for both methods under investigation. The same held for the correlation of findings from CT and the 125I-hydroxylapatite technique, where the level of significance was also p=0.001. The above statements must, however, be modified in as much as the mineral salt values measured by CT were consistently lower than those obtained on the basis of 125I-photon absorption. These deviations are chiefly attributable to the fact that the values provided by CT are more susceptible to influences from the fat contained in the bones. In 125I-photon absorption a special formula may be derived to allow for the bias occurring here, provided that the composition of the bone is known. To summarise, the relative advantages and drawbacks of CT and 125I-photon absorption are carefully balanced. Mineral salt evaluations by CT permit incipient losses to be ascertained even in the trunk. The 125I-photon absorption technique would appear to be the obvious method for any kind of follow-up examination in the peripheral skeleton, as it is easily reproducible and radiation exposure can be kept to minimum. (TRV)

  18. LightForce photon-pressure collision avoidance: Efficiency analysis in the current debris environment and long-term simulation perspective

    Science.gov (United States)

    Yang Yang, Fan; Nelson, Bron; Aziz, Jonathan; Carlino, Roberto; Dono Perez, Andres; Faber, Nicolas; Foster, Cyrus; Frost, Chad; Henze, Chris; Karacalıoğlu, Arif Göktuğ; Levit, Creon; Marshall, William; Mason, James; O'Toole, Conor; Swenson, Jason; Worden, Simon P.; Stupl, Jan

    2016-09-01

    This work provides an efficiency analysis of the LightForce space debris collision avoidance scheme in the current debris environment and describes a simulation approach to assess its impact on the long-term evolution of the space debris environment. LightForce aims to provide just-in-time collision avoidance by utilizing photon pressure from ground-based industrial lasers. These ground stations impart minimal accelerations to increase the miss distance for a predicted conjunction between two objects. In the first part of this paper we will present research that investigates the short-term effect of a few systems consisting of 20 kW class lasers directed by 1.5 m diameter telescopes using adaptive optics. The results found such a network of ground stations to mitigate more than 85 percent of conjunctions and could lower the expected number of collisions in Low Earth Orbit (LEO) by an order of magnitude. While these are impressive numbers that indicate LightForce's utility in the short-term, the remaining 15 % of possible collisions contain (among others) conjunctions between two massive objects that would add large amount of debris if they collide. Still, conjunctions between massive objects and smaller objects can be mitigated. Hence, we choose to expand the capabilities of the simulation software to investigate the overall effect of a network of LightForce stations on the long-term debris evolution. In the second part of this paper, we will present the planned simulation approach for that effort. For the efficiency analysis of collision avoidance in the current debris environment, we utilize a simulation approach that uses the entire Two Line Element (TLE) catalog in LEO for a given day as initial input. These objects are propagated for one year and an all-on-all conjunction analysis is performed. For conjunctions that fall below a range threshold, we calculate the probability of collision and record those values. To assess efficiency, we compare a baseline

  19. Overlay Alignment Using Two Photonic Crystals

    CERN Document Server

    Peng, C; Morton, K; Yu, Z; Chou, Stephen Y.; Morton, Keith; Peng, Can; Yu, Zhaoning

    2005-01-01

    In this paper we proposed a novel overlay alignment method using two sets of identical photonic crystals (PhCs). In this method the reflection or transmission spectrum of the two overlaid photonic crystals is measured to help wafer tilt, yaw rotation, and translation aligning. The initial testing results with two 1D photonic crystals and analysis of the alignment accuracy are presented. This method is particularly useful in building photonic crystal stacks with nanoimprint lithography (NIL).

  20. LightForce Photon-Pressure Collision Avoidance: Updated Efficiency Analysis Utilizing a Highly Parallel Simulation Approach

    Science.gov (United States)

    Stupl, Jan; Faber, Nicolas; Foster, Cyrus; Yang, Fan Yang; Nelson, Bron; Aziz, Jonathan; Nuttall, Andrew; Henze, Chris; Levit, Creon

    2014-01-01

    This paper provides an updated efficiency analysis of the LightForce space debris collision avoidance scheme. LightForce aims to prevent collisions on warning by utilizing photon pressure from ground based, commercial off the shelf lasers. Past research has shown that a few ground-based systems consisting of 10 kilowatt class lasers directed by 1.5 meter telescopes with adaptive optics could lower the expected number of collisions in Low Earth Orbit (LEO) by an order of magnitude. Our simulation approach utilizes the entire Two Line Element (TLE) catalogue in LEO for a given day as initial input. Least-squares fitting of a TLE time series is used for an improved orbit estimate. We then calculate the probability of collision for all LEO objects in the catalogue for a time step of the simulation. The conjunctions that exceed a threshold probability of collision are then engaged by a simulated network of laser ground stations. After those engagements, the perturbed orbits are used to re-assess the probability of collision and evaluate the efficiency of the system. This paper describes new simulations with three updated aspects: 1) By utilizing a highly parallel simulation approach employing hundreds of processors, we have extended our analysis to a much broader dataset. The simulation time is extended to one year. 2) We analyze not only the efficiency of LightForce on conjunctions that naturally occur, but also take into account conjunctions caused by orbit perturbations due to LightForce engagements. 3) We use a new simulation approach that is regularly updating the LightForce engagement strategy, as it would be during actual operations. In this paper we present our simulation approach to parallelize the efficiency analysis, its computational performance and the resulting expected efficiency of the LightForce collision avoidance system. Results indicate that utilizing a network of four LightForce stations with 20 kilowatt lasers, 85% of all conjunctions with a

  1. Growth analysis of UV-B-irradiated cucumber seedlings as influenced by photosynthetic photon flux source and cultivar

    International Nuclear Information System (INIS)

    A growth analysis was made of ultraviolet-B (UV-B)-sensitive (Poinsett) and insensitive (Ashley) cultivars of Cucuumis satives L. grown in growth chambers at 600 μmol m−2 s−1 of photosynthetic photon flux (PPF) provided by red- and far-red-deficient metal halide (MH) or blue- and UV-A-deficient high pressure sodium/deluxe f HPS/DX) lamps. Plants were irradiated 6 h daily with 0.2 f-UV-B) or 18.2 C+UV-B) kJ m−2 day−1 of biologically effective UV-B for 8 or 15 days from time of seeding. In general, plants given supplemental UV-B for 15 days showed lower leaf area ratio (LARs, and higher specific leaf mass (SLM) mean relative growth rate (MRGR) and net assimilation rate (NAR) than that of control plants, but they showed no difference in leaf mass ratio (LMR), Plants grown under HPS/DX lamps vs MH lamps showed higher SLM and NAR. lower LAR and LMR. hut no difference in MRGR. LMR was the only growth parameter affected by cultivar: at 15 days, it was slightly greater in Poinsett than in Ashley. There were no interactive effects of UV-B. PPF source or cultivar on any of the growth parameters determined, indicating that the choice of either HPS/DX or MH lamps should not affect growth response to UV-B radiation. This was true even though leaves of UV-B-irradiated plants grown under HPS/DX lamps have been shown to have greater chlorosis than those grown under MH lamps. (author)

  2. Influence of photon energy on the quality of prostate intensity modulated radiation therapy plans based on analysis of physical indices

    International Nuclear Information System (INIS)

    The goal of the present study was to study the effects of low- and high-energy intensity-modulated photon beams on the planning of target volume and the critical organs in cases of localized prostate tumors in a cohort of 8 patients. To ensure that the difference between the plans is due to energy alone, all other parameters were kept constant. A mean dose volume histogram (DVH) for each value of energy and for each contoured structure was created and was considered as completely representative for all patients. To facilitate comparison between 6-MV and 15-MV beams, the DVH-s were normalized. The different parameters that were compared for 6-MV and 15-MV beams included mean DVH, different homogeneity indices, conformity index, etc. Analysis of several indices depicts more homogeneous dose for 15-MV beam and more conformity for 6-MV beam. Comparison of all these parameters showed that there was little difference between the 6-MV and 15-MV beams. For rectum, 2 to 4 % more volume received high dose with the 6-MV beam in comparison with the 15-MV beam, which was not clinically significant, since in practice much tighter constraints are maintained, such that Normal Tissue Complication Probability (NTCP) is kept within 5 %. Such tighter constraints might increase the dose to other regions and other critical organs but are unlikely to increase their complication probabilities. Hence the slight advantages of 15-MV beam in providing benefits of better normal-tissue sparing and better coverage cannot be considered to outweigh its well-known risk of non-negligible neutron production. (author)

  3. Influence of photon energy on the quality of prostate intensity modulated radiation therapy plans based on analysis of physical indices

    Directory of Open Access Journals (Sweden)

    Sundaram Thangavelu

    2011-01-01

    Full Text Available The goal of the present study was to study the effects of low- and high-energy intensity-modulated photon beams on the planning of target volume and the critical organs in cases of localized prostate tumors in a cohort of 8 patients. To ensure that the difference between the plans is due to energy alone, all other parameters were kept constant. A mean dose volume histogram (DVH for each value of energy and for each contoured structure was created and was considered as completely representative for all patients. To facilitate comparison between 6-MV and 15-MV beams, the DVH-s were normalized. The different parameters that were compared for 6-MV and 15-MV beams included mean DVH, different homogeneity indices, conformity index, etc. Analysis of several indices depicts more homogeneous dose for 15-MV beam and more conformity for 6-MV beam. Comparison of all these parameters showed that there was little difference between the 6-MV and 15-MV beams. For rectum, 2 to 4 % more volume received high dose with the 6-MV beam in comparison with the 15-MV beam, which was not clinically significant, since in practice much tighter constraints are maintained, such that Normal Tissue Complication Probability (NTCP is kept within 5 %. Such tighter constraints might increase the dose to other regions and other critical organs but are unlikely to increase their complication probabilities. Hence the slight advantages of 15-MV beam in providing benefits of better normal-tissue sparing and better coverage cannot be considered to outweigh its well-known risk of non-negligible neutron production.

  4. Influence of photon energy on the quality of prostate intensity modulated radiation therapy plans based on analysis of physical indices

    Science.gov (United States)

    Thangavelu, Sundaram; Jayakumar, S; Govindarajan, K N; Supe, Sanjay S.; Nagarajan, V; Nagarajan, M

    2011-01-01

    The goal of the present study was to study the effects of low- and high-energy intensity-modulated photon beams on the planning of target volume and the critical organs in cases of localized prostate tumors in a cohort of 8 patients. To ensure that the difference between the plans is due to energy alone, all other parameters were kept constant. A mean dose volume histogram (DVH) for each value of energy and for each contoured structure was created and was considered as completely representative for all patients. To facilitate comparison between 6-MV and 15-MV beams, the DVH-s were normalized. The different parameters that were compared for 6-MV and 15-MV beams included mean DVH, different homogeneity indices, conformity index, etc. Analysis of several indices depicts more homogeneous dose for 15-MV beam and more conformity for 6-MV beam. Comparison of all these parameters showed that there was little difference between the 6-MV and 15-MV beams. For rectum, 2 to 4 % more volume received high dose with the 6-MV beam in comparison with the 15-MV beam, which was not clinically significant, since in practice much tighter constraints are maintained, such that Normal Tissue Complication Probability (NTCP) is kept within 5 %. Such tighter constraints might increase the dose to other regions and other critical organs but are unlikely to increase their complication probabilities. Hence the slight advantages of 15-MV beam in providing benefits of better normal-tissue sparing and better coverage cannot be considered to outweigh its well-known risk of non-negligible neutron production. PMID:21430856

  5. Operating cost analysis of anaesthesia: Activity based costing (ABC analysis

    Directory of Open Access Journals (Sweden)

    Majstorović Branislava M.

    2011-01-01

    Full Text Available Introduction. Cost of anaesthesiology represent defined measures to determine a precise profile of expenditure estimation of surgical treatment, which is important regarding planning of healthcare activities, prices and budget. Objective. In order to determine the actual value of anaestesiological services, we started with the analysis of activity based costing (ABC analysis. Methods. Retrospectively, in 2005 and 2006, we estimated the direct costs of anestesiological services (salaries, drugs, supplying materials and other: analyses and equipment. of the Institute of Anaesthesia and Resuscitation of the Clinical Centre of Serbia. The group included all anesthetized patients of both sexes and all ages. We compared direct costs with direct expenditure, “each cost object (service or unit” of the Republican Health-care Insurance. The Summary data of the Departments of Anaesthesia documented in the database of the Clinical Centre of Serbia. Numerical data were utilized and the numerical data were estimated and analyzed by computer programs Microsoft Office Excel 2003 and SPSS for Windows. We compared using the linear model of direct costs and unit costs of anaesthesiological services from the Costs List of the Republican Health-care Insurance. Results. Direct costs showed 40% of costs were spent on salaries, (32% on drugs and supplies, and 28% on other costs, such as analyses and equipment. The correlation of the direct costs of anaestesiological services showed a linear correlation with the unit costs of the Republican Healthcare Insurance. Conclusion. During surgery, costs of anaesthesia would increase by 10% the surgical treatment cost of patients. Regarding the actual costs of drugs and supplies, we do not see any possibility of costs reduction. Fixed elements of direct costs provide the possibility of rationalization of resources in anaesthesia.

  6. Photon-Photon Interaction in a Photon Gas

    OpenAIRE

    Thoma, Markus H.

    2000-01-01

    Using the effective Lagrangian for the low energy photon-photon interaction the lowest order photon self energy at finite temperature and in non-equilibrium is calculated within the real time formalism. The Debye mass, the dispersion relation, the dielectric tensor, and the velocity of light following from the photon self energy are discussed. As an application we consider the interaction of photons with the cosmic microwave background radiation.

  7. Photon-Photon Scattering at the Photon Linear Collider

    OpenAIRE

    Jikia, G.; Tkabladze, A.

    1993-01-01

    Photon-photon scattering at the Photon Linear Collider is considered. Explicit formulas for helicity amplitudes due to $W$ boson loops are presented. It is shown that photon-photon scattering should be easily observable at PLC and separation of the $W$ loop contribution (which dominates at high energies) will be possible at $e^+e^-$ c.m. energy of 500~GeV or higher.

  8. Analysis of human enamel and dentine by neutron activation analysis

    International Nuclear Information System (INIS)

    Determination of trace elements in dental tissues has been of great interest to study the correlation between element composition and caries as well as food habits of individuals. In the present study dentine and enamel samples from healthy individuals were analysed by neutron activation analysis. The teeth were provided form dental clinics, and they were previously washed using purified water and acetone. Then they were dried at 40 deg C and ground in a agate mortar. The samples and element standards were irradiated with thermal neutrons at the IEA-R1 nuclear reactor. Long irradiations of 8 h under thermal neutron flux of 5x1012 n cm-2 s-1 were used for Ca, Na, Sr and Zn determinations. In short irradiations of 15 s and under neutron flux of 1012 n cm-2 s-1 the elements Mg, Mn, Na e Sr were determined. The induced gamma activities of the samples and standards were measured using a hyperpure Ge detector coupled to a gamma ray spectrometer. Elemental concentrations were calculated by comparative method. Results obtained showed that Ca, Mg and Na are present in both tissues at the level of percentages and the elements Mn, Sr and Zn at the μg g-1 levels. For quality control of the results the certified reference materials NIST 1400 Bone Ash and NIST 1486 Bone Meal were analysed. (author)

  9. Modeling of photonic Crystal Fibres

    DEFF Research Database (Denmark)

    Bjarklev, Anders Overgaard; Broeng, Jes; Barkou, Stig Eigil

    1999-01-01

    Diferent theoretical models for analysis of photonic crystal fibres are reviewed and compaired. The methods span from simple scalar approaches to full-vectorial models using different mode-field decompositions. The specific advantages of the methods are evaluated.......Diferent theoretical models for analysis of photonic crystal fibres are reviewed and compaired. The methods span from simple scalar approaches to full-vectorial models using different mode-field decompositions. The specific advantages of the methods are evaluated....

  10. Simultaneous speciation analysis using neutron activation

    International Nuclear Information System (INIS)

    Full text: Neutron activation analysis (NAA) is a well-established analytical technique for the simultaneous determination of multielement concentrations. Although various forms of NAA have been traditionally applied to measuring the total concentrations of elements, the scope of NAA can be further extended in conjunction with pre-irradiation chemical separations to determine the species of an element. The technique can then be called speciation NAA (SNAA). Since much of the toxicity of an element depends on its physico-chemical forms, there is an increasing interest in studying its speciation. A number of characteristic features of NAA, which other techniques normally do not possess, can be advantageously exploited in SNAA. For example, SNAA has simultaneous multielement specificity unlike AAS and AFS. The SNAA technique can be applied to the simultaneous speciation of elements which are not chemically similar such as Cd, Se and I, as well as to the elements such as Cl, Br and I which are rather difficult to determine by most other techniques. Qualitative as well as quantitative analysis of small samples can be done by SNAA with excellent precision, accuracy, sensitivity, and rapidity. Unlike many other techniques, SNAA has some enhanced quality assurance capabilities. We have developed SNAA methods for separating various inorganic and organic arsenic species in water and in sea foods. We are presently extending these methods to include simultaneous speciation of As, Sb and Se. We have also developed SNAA methods employing biochemical techniques for the characterization of metalloproteins and protein-bound trace element species of Se along with Cd, Cu, Mn, Mo and Zn in bovine kidneys. Lately, we have concentrated our efforts to develop SNAA methods in conjunction with HPLC, RPC, SEC, NMR and MS for the simultaneous separation and characterization of extractable organo chlorine, organo bromine and organo iodine species in fisheries samples. An overview of the

  11. Attenuation analysis of neutrons and photons generated by 52-MeV protons transmitted through shielding materials

    International Nuclear Information System (INIS)

    Attenuation of neutrons and photons transmitted through grahite, iron, water and ordinary concrete assemblies were studied using gold foils for thermal neutron and an NE-213 organic scintillation detector with an (n-γ) discrimination technique for spectral measurements. Source neutrons and photons were produced by 52-MeV proton bombardment of a 21.4-mm-thick graphite target placed in front of the assembly. The distributions of the light output from the scintillator were unfolded by the revised FERDO code. These experimental results were used as benchmark data on neutron and photon penetration by neutrons energy above 15MeV. Multigroup Monte Carlo, one-dimensional ANISN and two-dimensional DOT-3.5 transport calculations were performed with the DLC-58/HELLO group cross sections to compare with the measurement and to evaluate the cross sections. The DOT code was also used for the estimation of room-scattered neutron and photon contribution to the measured spectra. The results of the ANISN calculation of neutrons and the three-dimensional Monte Carlo calculation agreed with the experimental values except for high energy neutrons transmitted through water and graphite. The agreement of both calculations was well within the accuracy of 7% in the measured attenuation coefficients. For photons, the ANISN calculation gave >20% overestimation of the attenuation coefficients in the case of deep penetration through the medium for which the photon mean-free-path is shorter than that of neutrons, such as in iron and concrete. The result of the DOT calculation of neutrons down to thermal energy agreed well with the gold foil measurement in the absolute value. (author)

  12. Photon detectors

    International Nuclear Information System (INIS)

    J. Seguinot and T. Ypsilantis have recently described the theory and history of Ring Imaging Cherenkov (RICH) detectors. In this paper, I will expand on these excellent review papers, by covering the various photon detector designs in greater detail, and by including discussion of mistakes made, and detector problems encountered, along the way. Photon detectors are among the most difficult devices used in physics experiments, because they must achieve high efficiency for photon transport and for the detection of single photo-electrons. For gaseous devices, this requires the correct choice of gas gain in order to prevent breakdown and wire aging, together with the use of low noise electronics having the maximum possible amplification. In addition, the detector must be constructed of materials which resist corrosion due to photosensitive materials such as, the detector enclosure must be tightly sealed in order to prevent oxygen leaks, etc. The most critical step is the selection of the photocathode material. Typically, a choice must be made between a solid (CsI) or gaseous photocathode (TMAE, TEA). A conservative approach favors a gaseous photocathode, since it is continuously being replaced by flushing, and permits the photon detectors to be easily serviced (the air sensitive photocathode can be removed at any time). In addition, it can be argued that we now know how to handle TMAE, which, as is generally accepted, is the best photocathode material available as far as quantum efficiency is concerned. However, it is a very fragile molecule, and therefore its use may result in relatively fast wire aging. A possible alternative is TEA, which, in the early days, was rejected because it requires expensive CaF2 windows, which could be contaminated easily in the region of 8.3 eV and thus lose their UV transmission

  13. Photon locking

    OpenAIRE

    Sleva, E. T.; Xavier, I. M., Jr.; Zewail, A.H.

    1986-01-01

    A novel observation of photon locking—the optical analog of spin locking—is reported, demonstrating the applicability of phase-coherent pulse sequences. The experiments are reported for the optical transition of iodine gas at 589.7 nm using the pulse sequence XYX-XYX̄. Locking decay rates are presented as a function of pressure and compared with optical dephasing (echo-decay) rates.

  14. Photon findings

    OpenAIRE

    Urbina, Victor M.

    2000-01-01

    Two experiments were made using a microwave generator, which sent a narrow beam, through a metallic plate with horizontal movement. At the other end a horn antenna coupled to a field-strength detector. In linear polarization double cycloids paths were found and in circular polarization spiral paths were found. These experiments suggested that the photon is composed by two particles in dynamic equilibrium. The description of this model is given later as well as its parameters.

  15. Photon detectors

    Energy Technology Data Exchange (ETDEWEB)

    Va`vra, J.

    1995-10-01

    J. Seguinot and T. Ypsilantis have recently described the theory and history of Ring Imaging Cherenkov (RICH) detectors. In this paper, I will expand on these excellent review papers, by covering the various photon detector designs in greater detail, and by including discussion of mistakes made, and detector problems encountered, along the way. Photon detectors are among the most difficult devices used in physics experiments, because they must achieve high efficiency for photon transport and for the detection of single photo-electrons. For gaseous devices, this requires the correct choice of gas gain in order to prevent breakdown and wire aging, together with the use of low noise electronics having the maximum possible amplification. In addition, the detector must be constructed of materials which resist corrosion due to photosensitive materials such as, the detector enclosure must be tightly sealed in order to prevent oxygen leaks, etc. The most critical step is the selection of the photocathode material. Typically, a choice must be made between a solid (CsI) or gaseous photocathode (TMAE, TEA). A conservative approach favors a gaseous photocathode, since it is continuously being replaced by flushing, and permits the photon detectors to be easily serviced (the air sensitive photocathode can be removed at any time). In addition, it can be argued that we now know how to handle TMAE, which, as is generally accepted, is the best photocathode material available as far as quantum efficiency is concerned. However, it is a very fragile molecule, and therefore its use may result in relatively fast wire aging. A possible alternative is TEA, which, in the early days, was rejected because it requires expensive CaF{sub 2} windows, which could be contaminated easily in the region of 8.3 eV and thus lose their UV transmission.

  16. Nanowire photonics

    OpenAIRE

    Peter J. Pauzauskie; Peidong Yang

    2006-01-01

    The development of integrated electronic circuitry ranks among the most disruptive and transformative technologies of the 20th century. Even though integrated circuits are ubiquitous in modern life, both fundamental and technical constraints will eventually test the limits of Moore's law. Nanowire photonic circuitry constructed from myriad one-dimensional building blocks offers numerous opportunities for the development of next-generation optical information processors and spectroscopy. Howev...

  17. Topological photonics

    OpenAIRE

    Lu, Ling; Joannopoulos, John D.; Soljačić, Marin

    2014-01-01

    The application of topology, the mathematics of conserved properties under continuous deformations, is creating a range of new opportunities throughout photonics. This field was inspired by the discovery of topological insulators, in which interfacial electrons transport without dissipation, even in the presence of impurities. Similarly, the use of carefully designed wavevector-space topologies allows the creation of interfaces that support new states of light with useful and interesting prop...

  18. Neutron activation analysis applied to archaeological problems

    International Nuclear Information System (INIS)

    Among the various techniques, the main analytical methods used to characterize ceramics are undoubtedly XRF and INAA. The principles of NAA differ from those of XRF in that samples are irradiated by thermal neutrons from a nuclear reactor. During irradiation, a few neutrons are captured by the nuclei of atoms in the specimen. This process, called activation, causes some of the nuclei to become unstable. During and after neutron irradiation, these unstable nuclei emit γ rays with unique energies at rates defined by the characteristic half-lives of the radioactive nuclei. Identification of the radioactive nucleus is possible by measuring the γ ray energies. Determination of their intensities permits quantitative analysis of the elements in the sample. The use of NAA in ceramics by a combination of two or three irradiation, decay and measurement strategies allows the determination of the elements Ba, Ce, Cl, Co, Cs, Dy, Eu, Fe, Hf, K, La, Lu, Mn, Na, Nd, Rb, Sb, Sc, Sm, Sr, Ta, Tb, Th, U, Yb, Zn and Zr, if necessary by changing the irradiation, decay and measurement schemes. In general, XRF is more available, more rapid and less expensive than NAA. However, NAA offers a far greater number of elements, more sensitivity, superior precision and greater accuracy than XRF. On the other hand, NAA can be performed on extremely small samples (5-10 mg), meaning that only minor damage to valuable artefacts may be required

  19. Activation analysis for the Ignitor tokamak

    International Nuclear Information System (INIS)

    The purpose of the Ignitor experiment is to produce DT plasma regimes where ignition can take place. From the neutronics point of view, after a first period of machine set up and tuning in aneutronic operation, a second phase of 2.5 MeV neutron production with pure deuterium plasmas at increasing density is anticipated. After that, a transition phase to increasing percentage of tritium will be followed by several years of operations with 50% of tritium leading to short but intense 14-MeV neutron emission. To deal with the concerns due to the strong neutron emission, a detailed description of the actual Ignitor machine is implemented in the MCNP-4B Monte Carlo code to calculate the neutron fluxes in all machine components, taking in account the streaming through the ports. These fluxes are then used as input for the FISPACT-97 code for the analysis of the activation at the end of life and at intermediate times for safety assessment purposes. The resulting dose rate outside the device is also studied. The results point out that remote handling is needed for repair/maintenance of inner components following the DD operations, and that the access in the hall near the device could be restricted from the beginning of DT operations. The requirements on additional shield are discussed

  20. Neutron-activation analysis of plant materials

    International Nuclear Information System (INIS)

    The possibilities offered by non-destructive neutron activation analysis (NAA) for simultaneously determining a large number of micro- and macro-components in plant samples of Bulgarian origin have been studied. Three groups of elements are determined: short half-life isotopes: Al, Mg, Ca, Na, Mn, Cl, Cu; medium half-life isotopes: Br, Na, K; and long half-life isotopes: Fe, Cr, Co, Sc, Pb, Zn. The samples are kept for 1 minute in a fluxes of 6x1012 n.cm2.sec-1 (first group), and of 3x1011 n.cm2.sec-1 for 18 hours (second and third groups). Use is made of a Ge/Li detector and 4000-channel analyser. To test the accuracy of the method, the results of NAA for some standard specimens have been compared with the indicators of other conventional methods tested in 18 laboratories in various countries. The data from NAA for the content of K, Mo, Ca, Mn, Fe, Zn and Cu demonstrate a high degree of coincidence with those from the other methods. Chemical composition of 23 samples of experimental and field crops is determined