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Sample records for eas atmospheric cherenkov

  1. A method of observing cherenkov light from extensive air shower at Yakutsk EAS array

    NASA Astrophysics Data System (ADS)

    Timofeev, Lev; Anatoly, Ivanov

    2016-07-01

    Proposed a new method for measuring the cherenkov light from the extensive air shower (EAS) of cosmic rays (CR), which allows to determine not only the primary particle energy and angle of arrival, but also the parameters of the shower in the atmosphere - the maximum depth and "age". For measurements Cherenkov light produced by EAS is proposed to use a ground network of wide-angle telescopes which are separated from each other by a distance 100-300 m depending on the total number of telescopes operating in the coincidence signals, acting autonomously, or includes a detector of the charged components, radio waves, etc. as part of EAS. In a results such array could developed, energy measurement and CR angle of arrival data on the depth of the maximum and the associated mass of the primary particle generating by EAS. This is particularly important in the study of galactic cosmic ray in E> 10^14 eV, where currently there are no direct measurements of the maximum depth of the EAS.

  2. Extension of Cherenkov Light LDF Parametrization for Tunka and Yakutsk EAS Arrays

    NASA Astrophysics Data System (ADS)

    Al-Rubaiee, A. A.

    2014-12-01

    The Cherenkov light Lateral Distribution Function (LDF) from particles initiated Extensive Air Showers (EAS) with ultrahigh energies (E > 1016 eV) was simulated using CORSIKA program for configuration of Tunka and Yakutsk EAS arrays for different primary particles (p, Fe and O2) and different zenith angles. By depending on the Breit-Wigner function, a parametrization of the Cherenkov light LDF was reconstructed on the basis of this simulation as a function of the primary energy. The comparison of the approximated Cherenkov light LDF with that measured on Tunka and Yakutsk EAS arrays gives the possibility of identification of energy spectrum and mass composition of particles initiating EAS about the knee region of the cosmic ray spectrum. The extrapolation of approximated Cherenkov light LDF for energies 20, 30 and 50 PeV was obtained for different primary particles and different zenith angles.

  3. Determining the primary cosmic ray energy from the total flux of Cherenkov light measured at the Yakutsk EAS array

    SciTech Connect

    Ivanov, A. A. Knurenko, S. P.; Sleptsov, I. E.

    2007-06-15

    We present a method for determining the energy of the primary particle that generates an extensive air shower (EAS) of comic rays based on measuring the total flux of Cherenkov light from the shower. Applying this method to Cherenkov light measurements at the Yakutsk EAS array has allowed us to construct the cosmic ray energy spectrum in the range 10{sup 15} - 3 x 10{sup 19} eV.

  4. Catching GRBs with atmospheric Cherenkov telescopes

    NASA Astrophysics Data System (ADS)

    Gilmore, R. C.; Primack, J. R.; Bouvier, A.; Otte, A. N.

    2011-08-01

    Fermi has shown GRBs to be a source of >10 GeV photons. We present an estimate of the detection rate of GRBs with a next generation Cherenkov telescope. Our predictions are based on the observed properties of GRBs detected by Fermi, combined with the spectral properties and redshift determinations for the bursts population by instruments operating at lower energies. While detection of VHE emission from GRBs has eluded ground-based instruments thus far, our results suggest that ground-based detection may be within reach of the proposed Cherenkov Telescope Array (CTA), albeit with a low rate, 0.25-0.5/yr. Such a detection would help constrain the emission mechanism of gamma-ray emission from GRBs. Photons at these energies from distant GRBs are affected by the UV-optical background light, and a ground-based detection could also provide a valuable probe of the Extragalactic Background Light (EBL) in place at high redshift.

  5. The experimental cascade curves of EAS at E sub 0 10(17) eV obtained by the method of detection of Cherenkov pulse shape

    NASA Technical Reports Server (NTRS)

    Fomin, Y. A.; Kalmykov, G. B.; Khristiansen, M. V.; Motova, M. V.; Nechin, Y. A.; Prosin, V. V.; Zhukov, V. Y.; Efimov, N. N.; Grigoriev, V. M.; Nikiforova, E. S.

    1985-01-01

    The individual cascade curves of EAS with E sub 0 10 to the 17th power eV/I to 3/ were studied by detection of EAS Cherenkov light pulses. The scintillators located at the center of the Yakutsk EAS array within a 500-m radius circle were used to select the showers and to determine the main EAS parameters. The individual cascade curves N(t) were obtained using the EAS Cherenkov light pulses satisfying the following requirements: (1) the signal-to-noise ratio fm/delta sub n 15, (2) the EAS axis-detector distance tau sub 350 m, (3) the zenith angle theta 30 deg, (4) the probability for EAS to be detected by scintillators W 0.8. Condition (1) arises from the desire to reduce the amplitude distortion of Cherenkov pulses due to noise and determines the range of EAS sizes, N(t). The resolution times of the Cherenkov pulse shape detectors are tau sub 0 approx. 23 ns which results in distortion of a pulse during the process of the detection. The distortion of pulses due to the finiteness of tau sub 0 value was estimated. It is shown that the rise time of pulse becomes greater as tau sub 0.5/tau sub 0 ratio decreases.

  6. Application of imaging to the atmospheric Cherenkov technique

    NASA Technical Reports Server (NTRS)

    Cawley, M. F.; Fegan, D. J.; Gibbs, K.; Gorham, P. W.; Hillas, A. M.; Lamb, R. C.; Liebing, D. F.; Mackeown, P. K.; Porter, N. A.; Stenger, V. J.

    1985-01-01

    Turver and Weekes proposed using a system of phototubes in the focal plane of a large reflector to give an air Cherenkov camera for gamma ray astronomy. Preliminary results with a 19 element camera have been reported previously. In 1983 the camera was increased to 37 pixels; it has now been routinely operated for two years. A brief physical description of the camera, its mode of operation, and the data reduction procedures are presented. The Monte Carlo simultations on which these are based on also reviewed.

  7. Large size SiPM matrix for Imaging Atmospheric Cherenkov Telescopes applications

    NASA Astrophysics Data System (ADS)

    Ambrosi, G.; Corti, D.; Ionica, M.; Manea, C.; Mariotti, M.; Rando, R.; Reichardt, I.; Schultz, C.

    2016-07-01

    SiPM photo detectors are nowadays commonly used in many applications. For large size telescopes like MAGIC or the future Large Size Telescope (LST) of the Cherenkov Telescope Array (CTA) project, a pixel size of some square centimeters is needed. An analog amplifier and sum stage was built and characterized. A large and compact SiPM matrix prototype, with the associated focusing optics, was assembled into a monolithic light detector with an active area of 3 cm2. The performance of the electronics is tailored for Imaging Atmospheric Cherenkov Telescopes (IACT) applications, with fast signal and adequate signal-to-noise (S/N) ratio.

  8. Fast pattern recognition trigger for atmospheric cherenkov telescopes

    NASA Astrophysics Data System (ADS)

    Vardanyan, A. A.; Chilingarian, S. A.; Eppler, W.; Gemmeke, H.

    2001-08-01

    The ambitions to bridge the energy gap between ground based and satellite borne detectors requires to decrease the threshold of Cherenkov telescopes down to several tens of GeV. The images corresponding to such low energies and registered with high angular resolution will lead to rather complicated disconnected images. The standard second-momentum analysis will not be so effective as for images detected with less angular resolution and/or more compact mirrors and high incident energies above 300 GeV. Since the trigger rate at low thresholds can reach 1 MHz, the main tasks for an "intelligent" trigger are signal pattern recognition and background rejection. We propose to use the hardware neurochip SAND/1 (Simple Applicable Neural Device) as fast "intelligent" Pattern Recognition Trigger (PRT). In addition to decrease the registered event rate down to several kHz, the PRT will reject muon and hadron backgrounds online at present only possible off-line. Using a special board of hardware neural accelerators and evolutionary network training strategies we construct a PRT which meets both timing and pattern recognition requirements.

  9. ChEAS Data: The Chequamegon Ecosystem Atmosphere Study

    DOE Data Explorer

    Davis, Kenneth J. [Penn State

    The Chequamegon Ecosystem-Atmosphere Study (ChEAS) is a multi-organizational research effort studying biosphere/atmosphere interactions within a northern mixed forest in Northern Wisconsin. A primary goal is to understand the processes controlling forest-atmosphere exchange of carbon dioxide and the response of these processes to climate change. Another primary goal is to bridge the gap between canopy-scale flux measurements and the global CO2 flask sampling network. The ChEAS flux towers participate in AmeriFlux, and the region is an EOS-validation site. The WLEF tower is a NOAA-CMDL CO2 sampling site. ChEAS sites are primarily located within or near the Chequamegon-Nicolet National Forest in northern Wisconsin, with one site in the Ottawa National Forest in the upper peninsula of Michigan. Current studies observe forest/atmosphere exchange of carbon dioxide at canopy and regional scales, forest floor respiration, photosynthesis and transpiration at the leaf level and use models to scale to canopy and regional levels. EOS-validation studies quantitatively assess the land cover of the area using remote sensing and conduct extensive ground truthing of new remote sensing data (i.e. ASTER and MODIS). Atmospheric remote sensing work is aimed at understanding atmospheric boundary layer dynamics, the role of entrainment in regulating the carbon dioxide mixing ratio profiles through the lower troposphere, and feedback between boundary layer dynamics and vegetation (especially via the hydrologic cycle). Airborne studies have included include balloon, kite and aircraft observations of the CO2 profile in the troposphere.

  10. Supernova remnants and pulsar wind nebulae with Imaging Atmospheric Cherenkov Telescopes (IACTs)

    NASA Astrophysics Data System (ADS)

    Eger, Peter

    2015-08-01

    The observation of very-high-energy (VHE, E > 100 GeV) gamma rays is an excellent tool to study the most energetic and violent environments in the Galaxy. This energy range is only accessible with ground-based instruments such as Imaging Atmospheric Cherenkov Telescopes (IACTs) that reconstruct the energy and direction of the primary gamma ray by observing the Cherenkov light from the induced extended air showers in Earths atmosphere. The main goals of Galactic VHE gamma-ray science are the identification of individual sources of cosmic rays (CRs), such as supernova remnants (SNRs), and the study of other extreme astrophysical objects at the highest energies, such as gamma-ray binaries and pulsar wind nebulae (PWNe). One of the main challenges is the discrimination between leptonic and hadronic gamma-ray production channels. To that end, the gamma-ray signal from each individual source needs to be brought into context with the multi-wavelength environment of the astrophysical object in question, particularly with observations tracing the density of the surrounding interstellar medium, or synchrotron radiation from relativistic electrons. In this review presented at the European Cosmic Ray Symposium 2014 (ECRS2014), the most recent developments in the field of Galactic VHE gamma-ray science are highlighted, with particular emphasis on SNRs and PWNe.

  11. The Topo-trigger: a new concept of stereo trigger system for imaging atmospheric Cherenkov telescopes

    NASA Astrophysics Data System (ADS)

    López-Coto, R.; Mazin, D.; Paoletti, R.; Blanch Bigas, O.; Cortina, J.

    2016-04-01

    Imaging atmospheric Cherenkov telescopes (IACTs) such as the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) telescopes endeavor to reach the lowest possible energy threshold. In doing so the trigger system is a key element. Reducing the trigger threshold is hampered by the rapid increase of accidental triggers generated by ambient light (the so-called Night Sky Background NSB). In this paper we present a topological trigger, dubbed Topo-trigger, which rejects events on the basis of their relative orientation in the telescope cameras. We have simulated and tested the trigger selection algorithm in the MAGIC telescopes. The algorithm was tested using MonteCarlo simulations and shows a rejection of 85% of the accidental stereo triggers while preserving 99% of the gamma rays. A full implementation of this trigger system would achieve an increase in collection area between 10 and 20% at the energy threshold. The analysis energy threshold of the instrument is expected to decrease by ~ 8%. The selection algorithm was tested on real MAGIC data taken with the current trigger configuration and no γ-like events were found to be lost.

  12. PROBING THE PULSAR ORIGIN OF THE ANOMALOUS POSITRON FRACTION WITH AMS-02 AND ATMOSPHERIC CHERENKOV TELESCOPES

    SciTech Connect

    Linden, Tim; Profumo, Stefano

    2013-07-20

    Recent observations by PAMELA, Fermi-LAT, and AMS-02 have conclusively indicated a rise in the cosmic-ray positron fraction above 10 GeV, a feature which is impossible to mimic under the paradigm of secondary positron production with self-consistent Galactic cosmic-ray propagation models. A leading explanation for the positron fraction rise is an additional source of electron-positron pairs, for example one or more mature, energetic, and relatively nearby pulsars. We point out that any one of two well-known nearby pulsars, Geminga and Monogem, can satisfactorily provide enough positrons to reproduce AMS-02 observations. A smoking-gun signature of this scenario is an anisotropy in the arrival direction of the cosmic-ray electrons and positrons, which may be detectable by existing, or future, telescopes. The predicted anisotropy level is, at present, consistent with limits from Fermi-LAT and AMS-02. We argue that the large collecting area of atmospheric Cherenkov telescopes (ACTs) makes them optimal tools for detecting such an anisotropy. Specifically, we show that much of the proton and {gamma}-ray background which affects measurements of the cosmic-ray electron-positron spectrum with ACTs may be controlled in the search for anisotropies. We conclude that observations using archival ACT data could already constrain or substantiate the pulsar origin of the positron anomaly, while upcoming instruments (such as the Cherenkov Telescope Array) will provide strong constraints on the source of the rising positron fraction.

  13. Probing the Pulsar Origin of the Anomalous Positron Fraction with AMS-02 and Atmospheric Cherenkov Telescopes

    NASA Astrophysics Data System (ADS)

    Linden, Tim; Profumo, Stefano

    2013-07-01

    Recent observations by PAMELA, Fermi-LAT, and AMS-02 have conclusively indicated a rise in the cosmic-ray positron fraction above 10 GeV, a feature which is impossible to mimic under the paradigm of secondary positron production with self-consistent Galactic cosmic-ray propagation models. A leading explanation for the positron fraction rise is an additional source of electron-positron pairs, for example one or more mature, energetic, and relatively nearby pulsars. We point out that any one of two well-known nearby pulsars, Geminga and Monogem, can satisfactorily provide enough positrons to reproduce AMS-02 observations. A smoking-gun signature of this scenario is an anisotropy in the arrival direction of the cosmic-ray electrons and positrons, which may be detectable by existing, or future, telescopes. The predicted anisotropy level is, at present, consistent with limits from Fermi-LAT and AMS-02. We argue that the large collecting area of atmospheric Cherenkov telescopes (ACTs) makes them optimal tools for detecting such an anisotropy. Specifically, we show that much of the proton and γ-ray background which affects measurements of the cosmic-ray electron-positron spectrum with ACTs may be controlled in the search for anisotropies. We conclude that observations using archival ACT data could already constrain or substantiate the pulsar origin of the positron anomaly, while upcoming instruments (such as the Cherenkov Telescope Array) will provide strong constraints on the source of the rising positron fraction.

  14. Front-end electronics and data acquisition system for imaging atmospheric Cherenkov telescopes

    NASA Astrophysics Data System (ADS)

    Chen, Y. T.; de La Taille, C.; Suomijärvi, T.; Cao, Z.; Deligny, O.; Dulucq, F.; Ge, M. M.; Lhenry-Yvon, I.; Martin-Chassard, G.; Nguyen Trung, T.; Wanlin, E.; Xiao, G.; Yin, L. Q.; Yun Ky, B.; Zhang, L.; Zhang, H. Y.; Zhang, S. S.; Zhu, Z.

    2015-09-01

    In this paper, a front-end electronics based on an application-specific integrated circuit (ASIC) is presented for the future imaging atmospheric Cherenkov telescopes (IACTs). To achieve this purpose, a 16-channel ASIC chip, PARISROC 2 (Photomultiplier ARray Integrated in SiGe ReadOut Chip) is used in the analog signal processing and digitization. The digitized results are sent to the server by a user-defined User Datagram Protocol/Internet Protocol (UDP/IP) hardcore engine through Ethernet that is managed by a FPGA. A prototype electronics fulfilling the requirements of the Wide Field of View Cherenkov Telescope Array (WFCTA) of the Large High Altitude Air Shower Observatory (LHAASO) project has been designed, fabricated and tested to prove the concept of the design. A detailed description of the development with the results of the test measurements are presented. By using a new input structure and a new configuration of the ASIC, the dynamic range of the circuit is extended. A highly precise-time calibrating algorithm is also proposed, verified and optimized for the mass production. The test results suggest that the proposed electronics design fulfills the general specification of the future IACTs.

  15. Optimal strategies for observation of active galactic nuclei variability with Imaging Atmospheric Cherenkov Telescopes

    NASA Astrophysics Data System (ADS)

    Giomi, Matteo; Gerard, Lucie; Maier, Gernot

    2016-07-01

    Variable emission is one of the defining characteristic of active galactic nuclei (AGN). While providing precious information on the nature and physics of the sources, variability is often challenging to observe with time- and field-of-view-limited astronomical observatories such as Imaging Atmospheric Cherenkov Telescopes (IACTs). In this work, we address two questions relevant for the observation of sources characterized by AGN-like variability: what is the most time-efficient way to detect such sources, and what is the observational bias that can be introduced by the choice of the observing strategy when conducting blind surveys of the sky. Different observing strategies are evaluated using simulated light curves and realistic instrument response functions of the Cherenkov Telescope Array (CTA), a future gamma-ray observatory. We show that strategies that makes use of very small observing windows, spread over large periods of time, allows for a faster detection of the source, and are less influenced by the variability properties of the sources, as compared to strategies that concentrate the observing time in a small number of large observing windows. Although derived using CTA as an example, our conclusions are conceptually valid for any IACTs facility, and in general, to all observatories with small field of view and limited duty cycle.

  16. Cherenkov Counters

    SciTech Connect

    Barbero, Marlon

    2012-04-19

    When a charged particle passes through an optically transparent medium with a velocity greater than the phase velocity of light in that medium, it emits prompt photons, called Cherenkov radiation, at a characteristic polar angle that depends on the particle velocity. Cherenkov counters are particle detectors that make use of this radiation. Uses include prompt particle counting, the detection of fast particles, the measurement of particle masses, and the tracking or localization of events in very large, natural radiators such as the atmosphere, or natural ice fields, like those at the South Pole in Antarctica. Cherenkov counters are used in a number of different fields, including high energy and nuclear physics detectors at particle accelerators, in nuclear reactors, cosmic ray detectors, particle astrophysics detectors and neutrino astronomy, and in biomedicine for labeling certain biological molecules.

  17. Geomagnetic Field Effects on the Imaging Air Shower Cherenkov Technique

    NASA Astrophysics Data System (ADS)

    Commichau, S.C.; Biland, A.; Kranich, D.; de los Reyes, R.; Moralejo, A.; Sobczyńska, D.

    Imaging Air Cherenkov Telescopes (IACTs) detect the Cherenkov light flashes of Extended Air Showers (EAS) triggered by VHE gamma-rays impinging on the Earth's atmosphere. Due to the overwhelming background from hadron induced EAS, the discrimination of the rare gamma-like events is rather difficult, in particular at energies below 100 GeV. The influence of the Geomagnetic Field (GF) on the EAS development can further complicate this discrimination and, in addition, also systematically affect the gamma-efficiency and energy resolution of an IACT. Here we present the results from dedicated Monte Carlo (MC) simulations for the MAGIC telescope site, show the GF effects on real data as well as possible corrections for these effects.

  18. High energy gamma-ray observations of the Crab Nebula and pulsar with the Solar Tower Atmospheric Cherenkov Effect Experiment

    NASA Astrophysics Data System (ADS)

    Oser, Scott Michael

    The Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) is a new ground-based atmospheric Cherenkov telescope for gamma-ray astronomy. STACEE uses the large mirror area of a solar heliostat facility to achieve a low energy threshold. A prototype experiment which uses 32 heliostat mirrors with a total mirror area of ~1200 m2 has been constructed. This prototype, called STACEE-32, was used to search for high energy gamma-ray emission from the Crab Nebula and Pulsar. Observations taken between November 1998 and February 1999 yield a strong statistical excess of gamma- like events from the Crab, with a significance of +6.75σ in 43 hours of on-source observing time. No evidence for pulsed emission from the Crab Pulsar was found, and the upper limit on the pulsed fraction of the observed excess was < 5.5% at the 90% confidence level. A subset of the data was used to determine the integral flux of gamma rays from the Crab. We report an energy threshold of Eth = 190 +/- 60 GeV, and a measured integral flux of I(E > Eth) = (2.2 +/- 0.6 +/- 0.2) × 10-10 photons cm-2 s-1. The observed flux is in agreement with a continuation to lower energies of the power law spectrum seen at TeV energies.

  19. A new analysis strategy for detection of faint γ-ray sources with Imaging Atmospheric Cherenkov Telescopes

    NASA Astrophysics Data System (ADS)

    Becherini, Y.; Djannati-Ataï, A.; Marandon, V.; Punch, M.; Pita, S.

    2011-07-01

    A new background rejection strategy for γ-ray astrophysics with stereoscopic Imaging Atmospheric Cherenkov Telescopes (IACT), based on Monte Carlo (MC) simulations and real background data from the H.E.S.S. [High Energy Stereoscopic System, see [1].] experiment, is described. The analysis is based on a multivariate combination of both previously-known and newly-derived discriminant variables using the physical shower properties, as well as its multiple images, for a total of eight variables. Two of these new variables are defined thanks to a new energy evaluation procedure, which is also presented here. The method allows an enhanced sensitivity with the current generation of ground-based Cherenkov telescopes to be achieved, and at the same time its main features of rapidity and flexibility allow an easy generalization to any type of IACT. The robustness against Night Sky Background (NSB) variations of this approach is tested with MC simulated events. The overall consistency of the analysis chain has been checked by comparison of the real γ-ray signal obtained from H.E.S.S. observations with MC simulations and through reconstruction of known source spectra. Finally, the performance has been evaluated by application to faint H.E.S.S. sources. The gain in sensitivity as compared to the best standard Hillas analysis ranges approximately from 1.2 to 1.8 depending on the source characteristics, which corresponds to an economy in observation time of a factor 1.4 to 3.2.

  20. Capability of EAS Arrays for Gamma-Ray Astronomy

    SciTech Connect

    Smith, Andrew

    2007-07-12

    Current efforts in ground-based VHE gamma-ray astronomy use two methods: Atmospheric Cherenkov Telescopes (ACTs) and Extended Air Shower (EAS) Arrays. While ACTs typically have greater sensitivity to gamma-ray point sources and lower energy thresholds, EAS arrays have an enormous advantage in exposure to the sky due to their large field of view and high duty cycle. The lower sensitivity of EAS detectors is largely due to the fact that they sample only the particles in the longitudinal tail of the shower that reach the ground level, whereas ACTs are able to observe the shower development high in the atmosphere. An examination of the intrinsic capabilities and limitations of EAS arrays as instruments for gamma-ray astronomy is presented. The angular and energy resolution and effective area of an optimized detector is shown as well as an analysis of gamma/hadron separation. The capabilities of the optimized detector are compared to the recently proposed HAWC detector.

  1. Acceleration of atmospheric Cherenkov telescope signal processing to real-time speed with the Auto-Pipe design system

    NASA Astrophysics Data System (ADS)

    Tyson, Eric J.; Buckley, James; Franklin, Mark A.; Chamberlain, Roger D.

    2008-10-01

    The imaging atmospheric Cherenkov technique for high-energy gamma-ray astronomy is emerging as an important new technique for studying the high energy universe. Current experiments have data rates of ≈20TB/year and duty cycles of about 10%. In the future, more sensitive experiments may produce up to 1000 TB/year. The data analysis task for these experiments requires keeping up with this data rate in close to real-time. Such data analysis is a classic example of a streaming application with very high performance requirements. This class of application often benefits greatly from the use of non-traditional approaches for computation including using special purpose hardware (FPGAs and ASICs), or sophisticated parallel processing techniques. However, designing, debugging, and deploying to these architectures is difficult and thus they are not widely used by the astrophysics community. This paper presents the Auto-Pipe design toolset that has been developed to address many of the difficulties in taking advantage of complex streaming computer architectures for such applications. Auto-Pipe incorporates a high-level coordination language, functional and performance simulation tools, and the ability to deploy applications to sophisticated architectures. Using the Auto-Pipe toolset, we have implemented the front-end portion of an imaging Cherenkov data analysis application, suitable for real-time or offline analysis. The application operates on data from the VERITAS experiment, and shows how Auto-Pipe can greatly ease performance optimization and application deployment of a wide variety of platforms. We demonstrate a performance improvement over a traditional software approach of 32x using an FPGA solution and 3.6x using a multiprocessor based solution.

  2. Characterization of the winter atmospheric aerosols in Kyoto and Seoul using PIXE, EAS and IC

    NASA Astrophysics Data System (ADS)

    Ma, Chang-Jin; Kasahara, Mikio; Tohno, Susumu; Hwang, Kyung-Chul

    Characteristics of atmospheric aerosols in Kyoto, Japan and Seoul, Korea were investigated using particle-induced X-ray emission (PIXE), elemental analysis system (EAS) and ion chromatograph (IC). Atmospheric aerosols were collected into fine and coarse fractions using a two-stage filter pack sampler in Kyoto and Seoul in winter of 1998. PIXE was applied to analyze the middle and heavy elements with atomic number greater than 14 (Si), and EAS was applied to analyze the light elements such as H, C and N. The total mass concentration in Seoul was about two times higher than in Kyoto and the concentration of Ca, Si, and Ti that are mainly originated from soil were remarkably higher in Seoul. During an Asian dust storm event, the concentration of soil components increased dramatically and amounted to about 15 times higher than average concentration. The fine/coarse ratios of NH 4+, NO 3-, and SO 42- were extremely high in both sites. The fact that nearly 70% of fine particles in both Kyoto and Seoul consist of the light elements (N, C, and H) suggests the importance of light elements measurement. Good mass closure for fine particles with light element data was achieved.

  3. MACHETE: A transit imaging atmospheric Cherenkov telescope to survey half of the very high energy γ-ray sky

    NASA Astrophysics Data System (ADS)

    Cortina, J.; López-Coto, R.; Moralejo, A.

    2016-01-01

    Current imaging atmospheric Cherenkov telescopes for very high energy γ-ray astrophysics are pointing instruments with a field of view up to a few tens of sq deg. We propose to build an array of two non-steerable (drift) telescopes. Each of the telescopes would have a camera with a FOV of 5 × 60 sq deg oriented along the meridian. About half of the sky drifts through this FOV in a year. We have performed a Monte Carlo simulation to estimate the performance of this instrument. We expect it to survey this half of the sky with an integral flux sensitivity of ˜0.77% of the steady flux of the Crab Nebula in 5 years, an analysis energy threshold of ˜150 GeV and an angular resolution of ˜0.1°. For astronomical objects that transit over the telescope for a specific night, we can achieve an integral sensitivity of 12% of the Crab Nebula flux in a night, making it a very powerful tool to trigger further observations of variable sources using steerable IACTs or instruments at other wavelengths.

  4. Measurement of the Muon Atmospheric Production Depth with the Water Cherenkov Detectors of the Pierre Auger Observatory

    SciTech Connect

    Molina Bueno, Laura

    2015-09-01

    Ultra-high-energy cosmic rays (UHECR) are particles of uncertain origin and composition, with energies above 1 EeV (1018 eV or 0.16 J). The measured flux of UHECR is a steeply decreasing function of energy. The largest and most sensitive apparatus built to date to record and study cosmic ray Extensive Air Showers (EAS) is the Pierre Auger Observatory. The Pierre Auger Observatory has produced the largest and finest amount of data ever collected for UHECR. A broad physics program is being carried out covering all relevant topics of the field. Among them, one of the most interesting is the problem related to the estimation of the mass composition of cosmic rays in this energy range. Currently the best measurements of mass are those obtained by studying the longitudinal development of the electromagnetic part of the EAS with the Fluorescence Detector. However, the collected statistics is small, specially at energies above several tens of EeV. Although less precise, the volume of data gathered with the Surface Detector is nearly a factor ten larger than the fluorescence data. So new ways to study composition with data collected at the ground are under investigation. The subject of this thesis follows one of those new lines of research. Using preferentially the time information associated with the muons that reach the ground, we try to build observables related to the composition of the primaries that initiated the EAS. A simple phenomenological model relates the arrival times with the depths in the atmosphere where muons are produced. The experimental confirmation that the distributions of muon production depths (MPD) correlate with the mass of the primary particle has opened the way to a variety of studies, of which this thesis is a continuation, with the aim of enlarging and improving its range of applicability. We revisit the phenomenological model which is at the root of the analysis and discuss a new way to improve some aspects of the model. We carry

  5. Study of Cherenkov Light Lateral Distribution Function Around the Knee Region in Extensive Air Showers

    NASA Astrophysics Data System (ADS)

    Al-Rubaiee, A.; Hashim, U.; Marwah, M.; Al-Douri, Y.

    2015-06-01

    The Cherenkov light lateral distribution function (LDF) was simulated with the CORSIKA code in the energy range (10^{13} - 10^{16}) eV. This simulation was performed for conditions and configurations of the Tunka EAS Cherenkov array for the two primary particles (p and Fe). Basing on the simulated results, many approximated functions are structured for two primary particles and different zenith angles. This allowed us to reconstruct the EAS events, which is, to determine the type and energy of the primary particles that produced showers from signal amplitudes of Cherenkov radiation measured by the Tunka Cherenkov array experiment. Comparison of the calculated LDF of Cherenkov radiation with that measured at the Tunka EAS array shows the ability to identify the primary particle that initiated the EAS cascades by determining its primary energy around the knee region of the cosmic ray spectrum.

  6. On the potential of atmospheric Cherenkov telescope arrays for resolving TeV gamma-ray sources in the Galactic plane

    NASA Astrophysics Data System (ADS)

    Ambrogi, L.; De Oña Wilhelmi, E.; Aharonian, F.

    2016-07-01

    The potential of an array of imaging atmospheric Cherenkov telescopes to detect gamma-ray sources in complex regions has been investigated. The basic characteristics of the gamma-ray instrument have been parameterized using simple analytic representations. In addition to the ideal (Gaussian form) point spread function (PSF), the impact of more realistic non-Gaussian PSFs with tails has been considered. Simulations of isolated point-like and extended sources have been used as a benchmark to test and understand the response of the instrument. The capability of the instrument to resolve multiple sources has been analyzed and the corresponding instrument sensitivities calculated. The results are of particular interest for weak gamma-ray emitters located in crowded regions of the Galactic plane, where the chance of clustering of two or more gamma-ray sources within 1 deg is high.

  7. The History of Ground-Based Very High Energy Gamma-Ray Astrophysics with the Atmospheric Air Cherenkov Telescope Technique

    NASA Astrophysics Data System (ADS)

    Mirzoyan, Razmik

    2013-06-01

    In the recent two decades the ground-based technique of imaging atmosphericescopes has established itself as a powerful new discipline in science. As of today some ˜ 150 sources of gamma rays of very different types, of both galactic and extragalactic origin, have been discovered due to this technique. The study of these sources is providing clues to many basic questions in astrophysics, astro-particle physics, physics of cosmic rays and cosmology. The current generation of telescopes, despite the young age of the technique, offers a solid performance. The technique is still maturing, leading to the next generation large instrument known under the name Cherenkov Telescope Array. The latter's sensitivity will be an order of magnitude higher than that of the currently best instruments VERITAS, H.E.S.S. and MAGIC. This article is devoted to outlining the milestones in a long history that step-by-step have given shape to this technique and have brought about today's successful source marathon.

  8. Future water Cherenkov detectors

    SciTech Connect

    Bergevin, Marc

    2015-05-15

    In these proceedings a review of the current proposed large-scale Warer Cherenkov experiments is given. An argument is made that future water Cherenkov detectors would benefit in the investment in neutron detection technology. A brief overview will be given of proposed water Cherenkov experiments such as HYPER-K and MEMPHYS and other R and D experiments to demonstrate neutron capture in water Cherenkov detectors. Finally, innovation developed in the context of the now defunct LBNE Water R and D option to improve Water Cherenkov technology will be described.

  9. Electron-Muon Identification by Atmospheric Shower and Electron Beam in a New EAS Detector Concept

    NASA Astrophysics Data System (ADS)

    Iori, M.; Denizli, H.; Yilmaz, A.; Ferrarotto, F.; Russ, J.

    2015-03-01

    We present results demonstrating the time resolution and μ/e separation capabilities of a new concept for an EAS detector capable of measuring cosmic rays arriving with large zenith angles. This kind of detector has been designed to be part of a large area (several square kilometer) surface array designed to measure ultra high energy (10-200 PeV) τ neutrinos using the Earth-skimming technique. A criterion to identify electron-gammas is also shown and the particle identification capability is tested by measurements in coincidence with the KASKADE-GRANDE experiment in Karlsruhe, Germany.

  10. Investigating the Cherenkov light lateral distribution function for primary proton and iron nuclei in extensive air showers

    NASA Astrophysics Data System (ADS)

    Al-Rubaiee, A. A.; Hashim, U.; Al-Douri, Y.

    2015-11-01

    The lateral distribution function (LDF) of Cherenkov radiation in extensive air showers (EAS) was simulated by CORSIKA program for the conditions of Yakutsk Cherenkov array at the high energy range (1013-1016) eV for two primary particles (p and Fe) for different zenith angles. By depending on Breit-Wigner function for analyzing of Cherenkov light LDF, a parameterization of Cherenkov light LDF was reconstructed by depending on CORSIKA simulation as a function of primary energy. The comparison between the estimated Cherenkov light LDF with the LDF that measured on the Yakutsk EAS array gives the ability of particle identification that initiated the shower and determination of particle's energy around the knee region. The extrapolation of approximated Cherenkov light LDF for energies 20 and 30 PeV was obtained for primary particles (p and Fe).

  11. Total absorption Cherenkov spectrometers

    NASA Astrophysics Data System (ADS)

    Malinovski, E. I.

    2015-05-01

    A short review of 50 years of work done with Cherenkov detectors in laboratories at the Lebedev Physical Institute is presented. The report considers some issues concerning the use of Cherenkov total absorption counters based on lead glass and heavy crystals in accelerator experiments.

  12. Wavelength-shifted Cherenkov radiators

    NASA Technical Reports Server (NTRS)

    Krider, E. P.; Jacobson, V. L.; Pifer, A. E.; Polakos, P. A.; Kurz, R. J.

    1976-01-01

    The scintillation and Cherenkov responses of plastic Cherenkov radiators containing different wavelength-shifting fluors in varying concentrations have been studied in beams of low energy protons and pions. For cosmic ray applications, where large Cherenkov to scintillation ratios are desired, the optimum fluor concentrations are 0.000025 by weight or less.

  13. Volcanoes muon imaging using Cherenkov telescopes

    NASA Astrophysics Data System (ADS)

    Catalano, O.; Del Santo, M.; Mineo, T.; Cusumano, G.; Maccarone, M. C.; Pareschi, G.

    2016-01-01

    A detailed understanding of a volcano inner structure is one of the key-points for the volcanic hazards evaluation. To this aim, in the last decade, geophysical radiography techniques using cosmic muon particles have been proposed. By measuring the differential attenuation of the muon flux as a function of the amount of rock crossed along different directions, it is possible to determine the density distribution of the interior of a volcano. Up to now, a number of experiments have been based on the detection of the muon tracks crossing hodoscopes, made up of scintillators or nuclear emulsion planes. Using telescopes based on the atmospheric Cherenkov imaging technique, we propose a new approach to study the interior of volcanoes detecting of the Cherenkov light produced by relativistic cosmic-ray muons that survive after crossing the volcano. The Cherenkov light produced along the muon path is imaged as a typical annular pattern containing all the essential information to reconstruct particle direction and energy. Our new approach offers the advantage of a negligible background and an improved spatial resolution. To test the feasibility of our new method, we have carried out simulations with a toy-model based on the geometrical parameters of ASTRI SST-2M, i.e. the imaging atmospheric Cherenkov telescope currently under installation onto the Etna volcano. Comparing the results of our simulations with previous experiments based on particle detectors, we gain at least a factor of 10 in sensitivity. The result of this study shows that we resolve an empty cylinder with a radius of about 100 m located inside a volcano in less than 4 days, which implies a limit on the magma velocity of 5 m/h.

  14. Transforming Cherenkov radiation in metamaterials

    NASA Astrophysics Data System (ADS)

    Ginis, Vincent; Danckaert, Jan; Veretennicoff, Irina; Tassin, Philippe

    2015-08-01

    In this contribution, we explore the generation of light in transformation-optical media. When charged particles move through a transformation-optical material with a speed larger than the phase velocity of light in the medium, Cherenkov light is emitted. We show that the emitted Cherenkov cone can be modified with longitudinal and transverse stretching of the coordinates. Transverse coordinates stretching alters only the dimensions of the cone, whereas longitudinal stretching also changes the apparent velocity of the charged particle. These results demonstrate that the geometric formalism of transformation optics can be used not only for the manipulation of light beam trajectories, but also for controlling the emission of light, here for describing the Cherenkov cone in an arbitrary anisotropic medium. Subsequently, we illustrate this point by designing a radiator for a ring imaging Cherenkov radiator. Cherenkov radiators are used to identify unknown elementary particles by determining their mass from the Cherenkov radiation cone that is emitted as they pass through the detector apparatus. However, at higher particle momentum, the angle of the Cherenkov cone saturates to a value independent of the mass of the generating particle, making it difficult to effectively distinguish between different particles. Using our transformation optics description, we show how the Cherenkov cone and the cut-off can be controlled to yield a radiator medium with enhanced sensitivity for particle identification at higher momentum [Phys. Rev. Lett. 113, 167402 (2014)].

  15. Bokeh mirror alignment for Cherenkov telescopes

    NASA Astrophysics Data System (ADS)

    Ahnen, M. L.; Baack, D.; Balbo, M.; Bergmann, M.; Biland, A.; Blank, M.; Bretz, T.; Bruegge, K. A.; Buss, J.; Domke, M.; Dorner, D.; Einecke, S.; Hempfling, C.; Hildebrand, D.; Hughes, G.; Lustermann, W.; Mannheim, K.; Mueller, S. A.; Neise, D.; Neronov, A.; Noethe, M.; Overkemping, A.-K.; Paravac, A.; Pauss, F.; Rhode, W.; Shukla, A.; Temme, F.; Thaele, J.; Toscano, S.; Vogler, P.; Walter, R.; Wilbert, A.

    2016-09-01

    Imaging Atmospheric Cherenkov Telescopes (IACTs) need imaging optics with large apertures and high image intensities to map the faint Cherenkov light emitted from cosmic ray air showers onto their image sensors. Segmented reflectors fulfill these needs, and composed from mass production mirror facets they are inexpensive and lightweight. However, as the overall image is a superposition of the individual facet images, alignment remains a challenge. Here we present a simple, yet extendable method, to align a segmented reflector using its Bokeh. Bokeh alig nment does not need a star or good weather nights but can be done even during daytime. Bokeh alignment optimizes the facet orientations by comparing the segmented reflectors Bokeh to a predefined template. The optimal Bokeh template is highly constricted by the reflector's aperture and is easy accessible. The Bokeh is observed using the out of focus image of a near by point like light source in a distance of about 10 focal lengths. We introduce Bokeh alignment on segmented reflectors and demonstrate it on the First Geiger-mode Avalanche Cherenkov Telescope (FACT) on La Palma, Spain.

  16. Semiconductor film Cherenkov lasers

    NASA Astrophysics Data System (ADS)

    Walsh, John E.

    1994-12-01

    The technical achievements for the project 'Semiconductor Film Cherenkov Lasers' are summarized. Described in the fourteen appendices are the operation of a sapphire Cherenkov laser and various grating-coupled oscillators. These coherent radiation sources were operated over the spectral range extending from 3 mm down to 400 micrometers. The utility of various types of open, multi-grating resonators and mode-locked operation were also demonstrated. In addition to these experiments, which were carried out with a 10-100 kV pulse generator, a low-energy (3-3.6 MeV) Van de Graaff generator and a low-energy RF linac (2.8 MeV) were used to investigate the properties of continuum incoherent Smith-Purcell radiation. It was shown that levels of intensity comparable to the infrared beam lines on a synchrotron could be obtained and thus that grating-coupled sources are potentially an important new source for Fourier transform spectroscopy. Finally, a scanning electron microscope was adapted for investigating mu-electron-beam-driven far-infrared sources. At the close of the project, spontaneous emission over the 288-800 micrometers band had been observed. Intensity levels were in accord with expectations based on theory. One or more of the Appendices address these topics in detail.

  17. The arrival time distribution of EAS at Taro

    NASA Astrophysics Data System (ADS)

    Maeda, T.; Kuramochi, H.; Ono, S.; Sakuyama, H.; Suzuki, N.

    The arrival time distribution of EAS has been observed since 1995 at Taro cosmicray laboratory (200m above sea level). The EAS arrays consist of 1m2 and 0.25m2 scintillation detectors, 0.25m2 fast timing counters and ultra fast Cherenkov detectors (UFC). 169 0.25m2 scintillation detectors are arranged in alattice configuration with a unit distance of 1.5m. UFC is placed at 20m from the center of lattice array. The arrival time distribution has been analyzed with distance from EAS core (r=10-60m). One of the results shows that the radius of corvature increases as shower size (Ne), near to the EAS core.

  18. Josephson-vortex Cherenkov radiation

    SciTech Connect

    Mints, R.G.; Snapiro, I.B.

    1995-10-01

    We predict the Josephson-vortex Cherenkov radiation of an electromagnetic wave. We treat a long one-dimensional Josephson junction. We consider the wavelength of the radiated electromagnetic wave to be much less than the Josephson penetration depth. We use for calculations the nonlocal Josephson electrodynamics. We find the expression for the radiated power and for the radiation friction force acting on a Josephson vortex and arising due to the Cherenkov radiation. We calculate the relation between the density of the bias current and the Josephson vortex velocity.

  19. Cherenkov radiation oscillator without reflectors

    SciTech Connect

    Li, D.; Wang, Y.; Wei, Y.; Yang, Z.; Hangyo, M.; Miyamoto, S.

    2014-05-12

    This Letter presents a Cherenkov radiation oscillator with an electron beam travelling over a finitely thick plate made of negative-index materials. In such a scheme, the external reflectors required in the traditional Cherenkov oscillators are not necessary, since the electromagnetic energy flows backward in the negative-index materials, leading to inherent feedback. We theoretically analyzed the interaction between the electron beam and the electromagnetic wave, and worked out the growth rate and start current through numerical calculations. With the help of particle-in-cell simulation, the theoretical predictions are well demonstrated.

  20. The EAS-1000 array

    SciTech Connect

    Khristiansen, G.B.; Fomin, IU.A.; Chasnikov, I.IA.; Ivanenko, V.M.; Efimov, N.N. )

    1989-01-01

    The requirements for a newly constructed EAS array are summarized, and the EAS-1000 array now under construction is described. The array is depicted, and its accuracy in finding EAS parameters is shown. The expected statistics in observing EAS of different energies are presented for the most important scientific problems the array is supposed to solve.

  1. Cherenkov Radiation from e+e- Pairs and Its Effect on nu e InducedShowers

    SciTech Connect

    Mandal, Sourav K.; Klein, Spencer R.; Jackson, J. David

    2005-06-08

    We calculate the Cherenkov radiation from an e{sup +}e{sup -} pair at small separations, as occurs shortly after a pair conversion. The radiation is reduced (compared to that from two independent particles) when the pair separation is smaller than the wavelength of the emitted light. We estimate the reduction in light in large electromagnetic showers, and discuss the implications for detectors that observe Cherenkov radiation from showers in the Earth's atmosphere, as well as in oceans and Antarctic ice.

  2. Progress in Cherenkov femtosecond fiber lasers

    NASA Astrophysics Data System (ADS)

    Liu, Xiaomin; Svane, Ask S.; Lægsgaard, Jesper; Tu, Haohua; Boppart, Stephen A.; Turchinovich, Dmitry

    2016-01-01

    We review the recent developments in the field of ultrafast Cherenkov fiber lasers. Two essential properties of such laser systems—broad wavelength tunability and high efficiency of Cherenkov radiation wavelength conversion are discussed. The exceptional performance of the Cherenkov fiber laser systems are highlighted—dependent on the realization scheme, the Cherenkov lasers can generate the femtosecond output tunable across the entire visible and even the UV range, and for certain designs more than 40% conversion efficiency from the pump to Cherenkov signal can be achieved. The femtosecond Cherenkov laser with all-fiber architecture is presented and discussed. Operating in the visible range, it delivers 100-200 fs wavelength-tunable pulses with multimilliwatt output power and exceptionally low noise figure an order of magnitude lower than the traditional wavelength tunable supercontinuum-based femtosecond sources. The applications for Cherenkov laser systems in practical biophotonics and biomedical applications, such as bio-imaging and microscopy, are discussed.

  3. Cherenkov Source for PMT Calibrations

    NASA Astrophysics Data System (ADS)

    Kaptanoglu, Tanner; SNO+ at UC Berkeley Collaboration

    2013-10-01

    My research is focused on building a deployable source for PMT calibrations in the SNO+ detector. I work for the SNO+ group at UC Berkeley headed by Gabriel Orebi Gann. SNO+ is an addition to the SNO project, and its main goal is to search for neutrinoless double beta decay. The detector will be monitored by over 9500 photomultiplier tubes (PMTs). In order to characterize the PMTs, several calibration sources are being constructed. One of which, the Cherenkov Source, will provide a well-understood source of non-isotropic light for calibrating the detector response. My goal is to design and construct multiple aspects of the Cherenkov Source. However, there are multiple questions that arose with its design. How do we keep the scintillation light inside the Cherenkov source so it does not contaminate calibration? How do we properly build the Cherenkov source: a hollow acrylic sphere with a neck? Can we maintain a clean source throughout these processes? These are some of the problems I have been working on, and will continue to work on, until the deployment of the source. Additionally, I have worked to accurately simulate the physics inside the source, mainly the energy deposition of alphas.

  4. Pilot study of ultra-high energy Cosmic rays through their Space - Atmospheric interactions - COSAT

    NASA Astrophysics Data System (ADS)

    Gina Isar, Paula; Nicolae, Doina

    2015-03-01

    One hundred years after the discovery of cosmic rays, the study of charged ultra-high energy cosmic rays remains a vital activity in fundamental physics. While primary cosmic rays could not be measured directly until it was possible to get the detectors high in the atmosphere using balloons or spacecraft, nowadays very energetic cosmic rays are detected indirectly by ground-based experiments measuring their Extensive Air Showers (EAS) induced Cherenkov and fluorescent light, or radio waves. Moreover, all cosmic ray measurements (performed either from space or ground) rely on accurate understandings of atmospheric phenomena. The concept of the COSAT project is the inter-link between Astroparticle Physics, Remote Sensing and Atmospheric Environment, willing to investigate the energetic cosmic rays physical processes using the atmosphere as a detector in order to identify potential scientific niches in the field of space sciences. A short introduction on the current status and perspectives of the national partnership COSAT project will be given.

  5. Longitudinal evolution of extensive air showers according to the results of Cherenkov-light studies

    SciTech Connect

    Kalmykov, N.N.; Khristiansen, G.B.; Prosin, V.V.

    1995-09-01

    The results of an analysis of the longitudinal evolution of Extensive Air Showers (EAS) with the aid of experimental recording the space-time structure of shower-induced Cherenkov radiation with the Yakutsk and Samarkand arrays are summarized. The combined data from these experiments make it possible to obtain the energy dependence of the mean depth of the EAS maximum in the wide energy range 3 x 10{sup 15} - 5 x 10{sup 17} eV, the shape of the mean cascade curve, and the depth distribution of EAS maxima at E{sub 0} = 10{sup 16} eV. The cross section for the inelastic interaction of 10{sup 16}-eV protons with the nuclei of air atoms is estimated. 14 refs., 8 figs.

  6. Aerogel Cherenkov detectors in colliding beam experiments

    NASA Astrophysics Data System (ADS)

    Danilyuk, A. F.; Kononov, S. A.; Kravchenko, E. A.; Onuchin, A. P.

    2015-05-01

    This review discusses the application of aerogel Cherenkov detectors in colliding beam experiments. Such detectors are used for charged particle identification at velocities at which other methods are ineffective. The paper examines aerogel production technology and how the aerogel optical parameters are measured. Data on threshold Cherenkov counters with direct light collection and on those using wavelength shifters are evaluated. Also presented are data on Ring Image Cherenkov detectors with single and multilayer focusing aerogel radiators.

  7. Calibration strategies for the Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    Gaug, Markus; Berge, David; Daniel, Michael; Doro, Michele; Förster, Andreas; Hofmann, Werner; Maccarone, Maria C.; Parsons, Dan; de los Reyes Lopez, Raquel; van Eldik, Christopher

    2014-08-01

    The Central Calibration Facilities workpackage of the Cherenkov Telescope Array (CTA) observatory for very high energy gamma ray astronomy defines the overall calibration strategy of the array, develops dedicated hardware and software for the overall array calibration and coordinates the calibration efforts of the different telescopes. The latter include LED-based light pulsers, and various methods and instruments to achieve a calibration of the overall optical throughput. On the array level, methods for the inter-telescope calibration and the absolute calibration of the entire observatory are being developed. Additionally, the atmosphere above the telescopes, used as a calorimeter, will be monitored constantly with state-of-the-art instruments to obtain a full molecular and aerosol profile up to the stratosphere. The aim is to provide a maximal uncertainty of 10% on the reconstructed energy-scale, obtained through various independent methods. Different types of LIDAR in combination with all-sky-cameras will provide the observatory with an online, intelligent scheduling system, which, if the sky is partially covered by clouds, gives preference to sources observable under good atmospheric conditions. Wide-field optical telescopes and Raman Lidars will provide online information about the height-resolved atmospheric extinction, throughout the field-of-view of the cameras, allowing for the correction of the reconstructed energy of each gamma-ray event. The aim is to maximize the duty cycle of the observatory, in terms of usable data, while reducing the dead time introduced by calibration activities to an absolute minimum.

  8. Very-High-Energy Astrophysics with the Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    Mukherjee, Reshmi

    2016-04-01

    The Cherenkov Telescope Array (CTA) will be a new gamma-ray observatory in the energy band ~30 GeV to ~100 TeV, designed to achieve an order of magnitude improvement in sensitivity over the currently operating imaging atmospheric Cherenkov telescopes. CTA will probe known sources with unprecedented sensitivity, angular resolution, and spectral coverage, with the potential of detecting hundreds of new sources. The CTA Consortium will also conduct a number of Key Science Projects, including a Galactic Plane survey and a survey of one quarter of the extragalactic sky. Data taken by CTA will be accessible by members of the wider astronomical community, for the first time in this energy band. This presentation will give an overview of CTA, and its proposed key science program.Submitted with the CTA Consortium

  9. Optic detectors calibration for measuring ultra-high energy extensive air showers Cherenkov radiation by 532 nm laser

    NASA Astrophysics Data System (ADS)

    Knurenko, Stanislav; Petrov, Igor; Egorov, Yuri

    2015-08-01

    Calibration of a PMT matrix is crucial for the treatment of the data obtained with Cherenkov tracking detector. Furthermore, due to high variability of the aerosol abundance in the atmosphere depending on season, weather etc. A constant monitoring of the atmospheric transparency is required during the measurements. For this purpose, besides traditional methods, a station for laser atmospheric probing is used.

  10. Anomalous Cherenkov spin-orbit sound

    SciTech Connect

    Smirnov, Sergey

    2011-02-15

    The Cherenkov effect is a well-known phenomenon in the electrodynamics of fast charged particles passing through transparent media. If the particle is faster than the light in a given medium, the medium emits a forward light cone. This beautiful phenomenon has an acoustic counterpart where the role of photons is played by phonons and the role of the speed of light is played by the sound velocity. In this case the medium emits a forward sound cone. Here, we show that in a system with spin-orbit interactions in addition to this normal Cherenkov sound there appears an anomalous Cherenkov sound with forward and backward sound propagation. Furthermore, we demonstrate that the transition from the normal to anomalous Cherenkov sound happens in a singular way at the Cherenkov cone angle. The detection of this acoustic singularity therefore represents an alternative experimental tool for the measurement of the spin-orbit coupling strength.

  11. Recent multiwave Cherenkov generator experiments

    SciTech Connect

    Adler, R.; Richter-Sand, R.; Hacker, F.; Walsh, J.; Arman, M.

    1994-12-31

    The initial operating characteristics of the North Star Research Corporation (NSRC) multiwave generator experiment are discussed. The first radiation from the NSRC apparatus has now been observed and the immediate goal is to optimize the power output by providing a beam which is better matched to the field profile (a thinner beam propagating closer to the vanes). When this has been accomplished a detailed comparison of the performance of MWCG/MWDG (multiwave diffraction generator/multiwave Cherenkov generator) structures with BWO structures of the same interaction length will be undertaken.

  12. New optics for resolution improving of Ring Imaging Cherenkov detectors

    NASA Astrophysics Data System (ADS)

    Šulc, M.; Kramer, D.; Polak, J.; Steiger, L.; Finger, M.; Slunecka, M.

    2013-04-01

    The Ring Imaging Cherenkov detector (RICH) of the COMPASS experiment at CERN is key tool for particle identification. Two reflecting spherical mirror surfaces, covering a total area of about 21 m2 hosted in the radiator vessel, provide Cherenkov radiation focusing to photon detectors. These ones are based on the use of multi-anode photo-multiplier tubes. They are coupled to individual lens telescopes, made from special fused silica aspherical lenses. Design, construction, and Hartmann test of lenses qualities and alignment were described. The RICH detector uses C4F10 as radiator gas. The refractive index of the radiator gas is substantial parameter. It varies with temperature, atmospheric pressure and gas purity. Its accurate knowledge is essential for the particle identification performance. A modified Jamin's interferometer was proposed, constructed and tested to allow on-line refractive index measurement with accuracy better than 10-6 The new types of fused silica Cherenkov radiators was designed to the tests of electron multiplier detector too.

  13. Cherenkov Telescopes Results on Pulsar Wind Nebulae and Pulsars

    NASA Astrophysics Data System (ADS)

    Wilhelmi, Emma De Oña

    The last few years have seen a revolution in very high γ-ray astronomy (VHE; E>100 GeV) driven largely by a new generation of Cherenkov telescopes. These new facilities, namely H.E.S.S. (High Energy Stereoscopic System), MAGIC (Major Atmospheric Gamma Imaging Cherenkov Telescope) and its upgrade MAGIC 2, VERITAS (Very Energetic Radiation Imaging Telescope Array System) and CANGAROO (Collaboration of Australia and Nippon for a Gamma Ray Observatory in the Outback) were designed to increase the flux sensitivity in the energy regime of hundreds of GeV, expanding the observed energy range from 50 to multi-TeV, and fostered as a result a period of rapid growth in our understanding of the Non-ThermalUniverse. As a result of this fast development the number of pulsar wind nebulae (PWNe) detected has increased from a few in the early 90's to more than two dozen of firm candidates nowadays. Also, the low energy threshold achieved allows to investigate the pulsed spectra of the high energy pulsars powering PWNe. A review of the most relevant VHE results concerning pulsars and their relativistic winds is discussed here in the context of Cherenkov telescopes.

  14. Normalized and asynchronous mirror alignment for Cherenkov telescopes

    NASA Astrophysics Data System (ADS)

    Ahnen, M. L.; Baack, D.; Balbo, M.; Bergmann, M.; Biland, A.; Blank, M.; Bretz, T.; Bruegge, K. A.; Buss, J.; Domke, M.; Dorner, D.; Einecke, S.; Hempfling, C.; Hildebrand, D.; Hughes, G.; Lustermann, W.; Mannheim, K.; Mueller, S. A.; Neise, D.; Neronov, A.; Noethe, M.; Overkemping, A.-K.; Paravac, A.; Pauss, F.; Rhode, W.; Shukla, A.; Temme, F.; Thaele, J.; Toscano, S.; Vogler, P.; Walter, R.; Wilbert, A.

    2016-09-01

    Imaging Atmospheric Cherenkov Telescopes (IACTs) need imaging optics with large apertures and high image intensities to map the faint Cherenkov light emitted from cosmic ray air showers onto their image sensors. Segmented reflectors fulfill these needs, and as they are composed from mass production mirror facets they are inexpensive and lightweight. However, as the overall image is a superposition of the individual facet images, alignment is a challenge. Here we present a computer vision based star tracking alignment method, which also works for limited or changing star light visibility. Our method normalizes the mirror facet reflection intensities to become independent of the reference star's intensity or the cloud coverage. Using two CCD cameras, our method records the mirror facet orientations asynchronously of the telescope drive system, and thus makes the method easy to integrate into existing telescopes. It can be combined with remote facet actuation, but does not require one to work. Furthermore, it can reconstruct all individual mirror facet point spread functions without moving any mirror. We present alignment results on the 4 m First Geiger-mode Avalanche Cherenkov Telescope (FACT).

  15. Cherenkov and Scintillation Properties of Cubic Zirconium

    NASA Technical Reports Server (NTRS)

    Christl, M.J.; Adams, J.H.; Parnell, T.A.; Kuznetsov, E.N.

    2008-01-01

    Cubic zirconium (CZ) is a high index of refraction (n =2.17) material that we have investigated for Cherenkov counter applications. Laboratory and proton accelerator tests of an 18cc sample of CZ show that the expected fast Cherenkov response is accompanied by a longer scintillation component that can be separated by pulse shaping. This presents the possibility of novel particle spectrometers which exploits both properties of CZ. Other high index materials being examined for Cherenkov applications will be discussed. Results from laboratory tests and an accelerator exposure will be presented and a potential application in solar energetic particle instruments will be discussed

  16. All-fiber femtosecond Cherenkov radiation source.

    PubMed

    Liu, Xiaomin; Lægsgaard, Jesper; Møller, Uffe; Tu, Haohua; Boppart, Stephen A; Turchinovich, Dmitry

    2012-07-01

    An all-fiber femtosecond source of spectrally isolated Cherenkov radiation is reported, to the best of our knowledge, for the first time. Using a monolithic, self-starting femtosecond Yb-doped fiber laser as the pump source and the combination of photonic crystal fibers as the wave-conversion medium, we demonstrate milliwatt-level, stable, and tunable Cherenkov radiation at visible wavelengths 580-630 nm, with pulse duration of sub-160-fs, and the 3 dB spectral bandwidth not exceeding 36 nm. Such an all-fiber Cherenkov radiation source is promising for practical applications in biophotonics such as bioimaging and microscopy. PMID:22743523

  17. Neutron Detection via the Cherenkov Effect

    SciTech Connect

    Bell, Zane W; Boatner, Lynn A

    2010-01-01

    We have incorporated neutron-absorbing elements in transparent, nonscintillating glasses and used the Cherenkov effect to convert neutron-induced beta-gamma radiation directly into light. Use of the Cherenkov effect requires glasses with a high index of refraction (to lower the threshold and increase the number of Cherenkov photons) and neutron absorbers resulting in radioactive products emitting high-energy beta or gamma radiation. In this paper, we present a brief description of the requirements for developing efficient Cherenkov-based neutron detectors, show the results of measurements of the response of representative samples to thermal and fast neutron fluxes, and give the results of a calculation of the expected response of a detector to a moderated fission spectrum.

  18. Deep Water Cherenkov Light Scatter Meter

    SciTech Connect

    Pappalardo, L; Petta, C.; Russo, G.V.

    2000-12-31

    The relevant parameters for the site choice of an underwater neutrino's telescope are discussed. The in situ measurement of the scattering distribution of the cherenkov light requires a suitable experimental setup. Its main features are described here.

  19. Test bench for front end electronic of the GCT camera for the Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    De Franco, A.; Cotter, G.

    2016-02-01

    The Gamma Cherenkov Telescope (GCT) is a design proposed to be part of the Small Sized Telescope (SST) array of the Cherenkov Telescope Array (CTA). The GCT camera is designed to record the flashes of atmospheric Cherenkov light from gamma and cosmic ray initiated cascades, which last only a few tens of nanoseconds. The camera thus needs very fast and compact electronics, addressed by the TARGET modules, based on homonymous ASICs which provide digitation at 1 GSample/s and the first level of trigger on the analog output of the photosensors. In this paper we describe a test bench lab set up to evaluate the performance and functionality of the camera' s front end electronics with an added educational value.

  20. Asymmetric Cherenkov acoustic reverse in topological insulators

    NASA Astrophysics Data System (ADS)

    Smirnov, Sergey

    2014-09-01

    A general phenomenon of the Cherenkov radiation known in optics or acoustics of conventional materials is a formation of a forward cone of, respectively, photons or phonons emitted by a particle accelerated above the speed of light or sound in those materials. Here we suggest three-dimensional topological insulators as a unique platform to fundamentally explore and practically exploit the acoustic aspect of the Cherenkov effect. We demonstrate that by applying an in-plane magnetic field to a surface of a three-dimensional topological insulator one may suppress the forward Cherenkov sound up to zero at a critical magnetic field. Above the critical field the Cherenkov sound acquires pure backward nature with the polar distribution differing from the forward one generated below the critical field. Potential applications of this asymmetric Cherenkov reverse are in the design of low energy electronic devices such as acoustic ratchets or, in general, in low power design of electronic circuits with a magnetic field control of the direction and magnitude of the Cherenkov dissipation.

  1. The Cherenkov Telescope Array For Very High-Energy Astrophysics

    NASA Astrophysics Data System (ADS)

    Kaaret, Philip

    2015-08-01

    The field of very high energy (VHE) astrophysics had been revolutionized by the results from ground-based gamma-ray telescopes, including the current imaging atmospheric Cherenkov telescope (IACT) arrays: HESS, MAGIC and VERITAS. A worldwide consortium of scientists from 29 countries has formed to propose the Cherenkov Telescope Array (CTA) that will capitalize on the power of this technique to greatly expand the scientific reach of ground-based gamma-ray telescopes. CTA science will include key topics such as the origin of cosmic rays and cosmic particle acceleration, understanding extreme environments in regions close to neutron stars and black holes, and exploring physics frontiers through, e.g., the search for WIMP dark matter, axion-like particles and Lorentz invariance violation. CTA is envisioned to consist of two large arrays of Cherenkov telescopes, one in the southern hemisphere and one in the north. Each array will contain telescopes of different sizes to provide a balance between cost and array performance over an energy range from below 100 GeV to above 100 TeV. Compared to the existing IACT arrays, CTA will have substantially better angular resolution and energy resolution, will cover a much wider energy range, and will have up to an order of magnitude better sensitivity. CTA will also be operated as an open observatory and high-level CTA data will be placed into the public domain; these aspects will enable broad participation in CTA science from the worldwide scientific community to fully capitalize on CTA's potential. This talk will: 1) review the scientific motivation and capabilities of CTA, 2) provide an overview of the technical design and the status of prototype development, and 3) summarize the current status of the project in terms of its proposed organization and timeline. The plans for access to CTA data and opportunities to propose for CTA observing time will be highlighed.Presented on behalf of the CTA Consortium.

  2. On-site mirror facet condensation measurements for the Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    Dipold, J.; Medina, M. C.; García, B.; Rasztocky, E.; Mancilla, A.; Maya, J.; Larrarte, J. J.; de Souza, V.

    2016-09-01

    The Imaging Atmospheric Cherenkov Technique (IACT) has provided very important discoveries in Very High Energy (VHE) γ-ray astronomy for the last two decades, being exploited mainly by experiments such as H.E.S.S., MAGIC and VERITAS. The same technique will be used by the next generation of γ-ray telescopes, Cherenkov Telescope Array - CTA, which is conceived to be an Observatory composed by two arrays strategically placed in both hemispheres, one in the Northern and one in the Southern. Each site will consist of several tens of Cherenkov telescopes of different sizes and will be equipped with about 10000 m2 of reflective surface. Because of its large size, the reflector of a Cherenkov telescope is composed of many individual mirror facets. Cherenkov telescopes operate without any protective system from weather conditions therefore it is important to understand how the reflective surfaces behave under different environmental conditions. This paper describes a study of the behavior of the mirrors in the presence of water vapor condensation. The operational time of a telescope is reduced by the presence of condensation on the mirror surface, therefore, to control and to monitor the formation of condensation is an important issue for IACT observatories. We developed a method based on pictures of the mirrors to identify the areas with water vapor condensation. The method is presented here and we use it to estimate the time and area two mirrors had condensation when exposed to the environmental conditions in the Argentinean site. The study presented here shows important guidelines in the selection procedure of mirror technologies and shows an innovative monitoring tool to be used in future Cherenkov telescopes.

  3. Relation between gamma-ray family and EAS core: Monte-Carlo simulation of EAS core

    NASA Technical Reports Server (NTRS)

    Yanagita, T.

    1985-01-01

    Preliminary results of Monte-Carlo simulation on Extensive Air Showers (EAS) (Ne=100,000) core is reported. For the first collision at the top of the atmosphere, high multiplicity (high rapidity, density) and a large Pt (1.5GeV average) model is assumed. Most of the simulated cores show a complicated structure.

  4. On Linsley Effect and Electromagnetic Radiation from Large EAS

    NASA Astrophysics Data System (ADS)

    Deb, Manab Jyoti

    The aim of the present work was to study the following aspects of EAS : i) Detection and determination of air showers parameters by measuring the particle densities. ii) Measurement of inclination of shower axis by recording arrival time distribution of shower front particles. iii) Measurement of FWHM of pulses photographed and study of Linsley effect. iv) Characteristics of Cherenkov radiation from air showers. v) Characteristics of low frequency (120 KHz) radio signal from showers. The experiments based on the above investigations were carried out at the Cosmic Ray Research Laboratory, Gauhati University, India, since September 91 to March, 1994. Electromagnetic radiation both optical Cherenkov radiation and radio frequency (120 KHz) as well as pulses associated with extensive air showers (EAS) of energy ranging from 1.5 X 1015ev to 2.1 X 10 18ev and zenith angles 15° < 0 < 60° were selected for the present analysis. The lateral distribution of Cherenkov pulses were assumed to have an exponential form fitted with an exponential law with an exponent reflecting the depth of shower maxima (Xm). The variation of rise time (FWHM) with core distance (R) was studied from pulses photographed. The high field associated with low frequency radio signal (120KHz) and its variation with primary energy (Ep), core distance and zenith angle (0) were observed. The thesis consists of the following five chapters: 1. INTRODUCTION - This chapter contains a brief history of cosmic rays, its composition, development of EAS, emission of electromagnetic radiation from EAS, a brief introduction to the present work including review of the earlier works and aim of the experiment. 2. THEORY - This chapter mainly reviews the theories and numerical calculations. 3. EXPERIMENTAL SET-UP - This chapter describes in detail the instrumentation developed, working principle, calibration etc. 4. DATA COLLECTION AND ANALYSIS - This chapter includes data collection, selection of data for required

  5. Cherenkov TOF PET with silicon photomultipliers

    NASA Astrophysics Data System (ADS)

    Dolenec, R.; Korpar, S.; Križan, P.; Pestotnik, R.

    2015-12-01

    As previously demonstrated, an excellent timing resolution below 100 ps FWHM is possible in time-of-flight positron emission tomography (TOF PET) if the detection method is based on the principle of detecting photons of Cherenkov light, produced in a suitable material and detected by microchannel plate photomultipliers (MCP PMTs). In this work, the silicon photomultipliers (SiPMs) were tested for the first time as the photodetectors in Cherenkov TOF PET. The high photon detection efficiency (PDE) of SiPMs led to a large improvement in detection efficiency. On the other hand, the time response of currently available SiPMs is not as good as that of MCP PMTs. The SiPM dark counts introduce a new source of random coincidences in Cherenkov method, which would be overwhelming with present SiPM technology at room temperature. When the apparatus was cooled, its performance significantly improved.

  6. The Cherenkov Surface Detector of the Pierre Auger Observatory

    NASA Astrophysics Data System (ADS)

    Billoir, Pierre

    2014-12-01

    The Pierre Auger Observatory detects the atmospheric showers induced by cosmic rays of ultra-high energy (UHE). It is the first one to use the hybrid technique. A set of telescopes observes the fluorescence of the nitrogen molecules on clear moonless nights, giving access to the longitudinal profile of the shower. These telescopes surround a giant array of 1600 water Cherenkov tanks (covering more than 3000 km2), which works continuously and samples the particles reaching the ground (mainly muons, photons and electrons/positrons); the light produced within the water is recorded into FADC (Fast Analog to Digital Convertes) traces. A subsample of hybrid events provides a cross calibration of the two components. We describe the structure of the Cherenkov detectors, their sensitivity to different particles and the information they can give on the direction of origin, the energy and the nature of the primary UHE object; we discuss also their discrimination power for rare events (UHE photons or neutrinos). To cope with the variability of weather conditions and the limitations of the communication system, the procedures for trigger and real time calibration have been shared between local processors and a central acquisition system. The overall system has been working almost continuously for 10 years, while being progressively completed and increased by the creation of a dense "infill" subarray.

  7. Metamaterials for Cherenkov Radiation Based Particle Detectors

    SciTech Connect

    Tyukhtin, A. V.; Schoessow, P.; Kanareykin, A.; Antipov, S.

    2009-01-22

    Measurement of Cherenkov radiation (CR) has long been a useful technique for charged particle detection and beam diagnostics. We are investigating metamaterials engineered to have refractive indices tailored to enhance properties of CR that are useful for particle detectors and that cannot be obtained using conventional media. Cherenkov radiation in dispersive media with a large refractive index differs significantly from the same effect in conventional detector media, like gases or aerogel. The radiation pattern of CR in dispersive metamaterials presents lobes at very large angles with respect to particle motion. Moreover, the frequency and particle velocity dependence of the radiated energy can differ significantly from CR in a conventional dielectric medium.

  8. The Ring Imaging Cherenkov detectors of DELPHI

    SciTech Connect

    Adam, W.; Albrecht, E.; Allen, D.

    1995-08-01

    A Ring Imaging Cherenkov (RICH) detector system has been built and is now in full operation within the DELPHI experiment. Large data samples of Z{sup 0} decays are being collected with good resolution on the observed Cherenkov angles. Several studies of Z{sup 0} decays using the RICH have already been performed on limited samples. Disturbance of the detector operation caused by shrinkage of polymeric construction materials and by migration of radiator substance is reported. These effects have been counteracted and do not endanger the quality of the data.

  9. 47 CFR 11.32 - EAS Encoder.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false EAS Encoder. 11.32 Section 11.32 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Equipment Requirements § 11.32 EAS Encoder. (a) EAS Encoders must at a minimum be capable of encoding the EAS protocol described in § 11.31 and providing the EAS...

  10. 47 CFR 11.32 - EAS Encoder.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false EAS Encoder. 11.32 Section 11.32 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Equipment Requirements § 11.32 EAS Encoder. (a) EAS Encoders must at a minimum be capable of encoding the EAS protocol described in § 11.31 and providing the EAS...

  11. 47 CFR 11.32 - EAS Encoder.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false EAS Encoder. 11.32 Section 11.32 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Equipment Requirements § 11.32 EAS Encoder. (a) EAS Encoders must at a minimum be capable of encoding the EAS protocol described in § 11.31 and providing the EAS...

  12. 47 CFR 11.33 - EAS Decoder.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false EAS Decoder. 11.33 Section 11.33 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Equipment Requirements § 11.33 EAS Decoder. (a) An EAS Decoder must at a minimum be capable of decoding the EAS protocol described in § 11.31, provide the EAS...

  13. 47 CFR 11.31 - EAS protocol.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false EAS protocol. 11.31 Section 11.31 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Equipment Requirements § 11.31 EAS protocol. (a) The EAS uses a four part message for an emergency activation of the EAS. The four parts are: Preamble and EAS Header...

  14. 47 CFR 11.33 - EAS Decoder.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false EAS Decoder. 11.33 Section 11.33 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Equipment Requirements § 11.33 EAS Decoder. (a) An EAS Decoder must at a minimum be capable of decoding the EAS protocol described in § 11.31, provide the EAS...

  15. Detection of reflected Cherenkov light from extensive air showers in the SPHERE experiment as a method of studying superhigh energy cosmic rays

    NASA Astrophysics Data System (ADS)

    Antonov, R. A.; Aulova, T. V.; Bonvech, E. A.; Galkin, V. I.; Dzhatdoev, T. A.; Podgrudkov, D. A.; Roganova, T. M.; Chernov, D. V.

    2015-01-01

    Although a large number of experiments were carried out during the last few decades, the uncertainty in the spectrum of all nuclei of primary cosmic rays (PCRs) with superhigh energies is still high, and the results of many experiments on nuclear composition of PCRs are contradictory. An overview of the SPHERE experiment on detecting Vavilov-Cherenkov radiation from extensive air shower (EAS) reflected from a ground snow surface is given. A number of experimental studies implementing this method are presented and their results are analyzed. Some other popular methods of studying PCRs with superhigh energies ( E 0 > 1015 eV) and their main advantages and drawbacks are briefly considered. The detecting equipment of the SPHERE-2 experiment and the technique of its calibration are considered. The optical properties of snow, which are important for experiments on reflected Cherenkov light (CL) from EAS, are discussed and the history of observing reflected EAS CL is described. The algorithm of simulating the detector response and calculating the fiducial acceptance of shower detection is described. The procedure of processing the experimental data with a subsequent reconstruction of the spectrum of all PCR nuclei and analysis of the mass composition is shown. The first results of reconstructing the spectrum and separating groups of cosmic-ray nuclei with high energies in the SPHERE-2 experiment are presented. Main sources of systematic errors are considered. The prospects of developing the technique of observation of reflected EAS CL in future experiments are discussed.

  16. The mechanism of Vavilov-Cherenkov radiation

    NASA Astrophysics Data System (ADS)

    Kobzev, A. P.

    2010-05-01

    The mechanism of generation of Vavilov-Cherenkov radiation is discussed in this article. The developers of the theory of the Vavilov-Cherenkov effect, I.E. Tamm and I.M. Frank, attributed this effect to their discovery of a new mechanism of radiation when a charged particle moves uniformly and rectilinearly in the medium. As such a mechanism presupposes the violation of the laws of conservation of energy and momentum, they proposed the abolition of these laws to account for the Vavilov-Cherenkov radiation mechanism. This idea has received a considerably wide acceptance in the creation of other theories, for example, transition radiation theory. In this paper, the radiation mechanism for the charge constant motion is demonstrated to be incorrect, because it contradicts not only the laws of conservation of energy and momentum, but also the very definitions of uniform and rectilinear motion (Newton's First Law). A consistent explanation of the Vavilov-Cherenkov radiation microscopic mechanism that does not contradict the basic laws is proposed. It is shown that the radiation arises from the interaction of the moving charge with bound charges that are spaced fairly far away from its trajectory. The Vavilov-Cherenkov radiation mechanism bears a slowing down character, but it differs fundamentally from bremsstrahlung, primarily because the Vavilov-Cherenkov radiation onset results from a two-stage process. First, the moving particle polarizes the medium; then, the already polarized atoms radiate coherently, provided that the particle velocity exceeds the phase speed of light in the medium. If the particle velocity is less than the phase speed of light in the medium, the polarized atoms return energy to the outgoing particle. In this case, radiation is not observed. Special attention is given to the relatively constant particle velocity as the condition of the coherent composition of waves. However, its motion cannot be designated as a uniform and rectilinear one in the

  17. Reverse surface-polariton cherenkov radiation.

    PubMed

    Tao, Jin; Wang, Qi Jie; Zhang, Jingjing; Luo, Yu

    2016-01-01

    The existence of reverse Cherenkov radiation for surface plasmons is demonstrated analytically. It is shown that in a metal-insulator-metal (MIM) waveguide, surface plasmon polaritons (SPPs) excited by an electron moving at a speed higher than the phase velocity of SPPs can generate Cherenkov radiation, which can be switched from forward to reverse direction by tuning the core thickness of the waveguide. Calculations are performed in both frequency and time domains, demonstrating that a radiation pattern with a backward-pointing radiation cone can be achieved at small waveguide core widths, with energy flow opposite to the wave vector of SPPs. Our study suggests the feasibility of generating and steering electron radiation in simple plasmonic systems, opening the gate for various applications such as velocity-selective particle detections. PMID:27477061

  18. Reverse surface-polariton cherenkov radiation

    NASA Astrophysics Data System (ADS)

    Tao, Jin; Wang, Qi Jie; Zhang, Jingjing; Luo, Yu

    2016-08-01

    The existence of reverse Cherenkov radiation for surface plasmons is demonstrated analytically. It is shown that in a metal-insulator-metal (MIM) waveguide, surface plasmon polaritons (SPPs) excited by an electron moving at a speed higher than the phase velocity of SPPs can generate Cherenkov radiation, which can be switched from forward to reverse direction by tuning the core thickness of the waveguide. Calculations are performed in both frequency and time domains, demonstrating that a radiation pattern with a backward-pointing radiation cone can be achieved at small waveguide core widths, with energy flow opposite to the wave vector of SPPs. Our study suggests the feasibility of generating and steering electron radiation in simple plasmonic systems, opening the gate for various applications such as velocity-selective particle detections.

  19. HAWC - The High Altitude Water Cherenkov Detector

    NASA Astrophysics Data System (ADS)

    Tepe, Andreas; HAWC Collaboration

    2012-07-01

    The high altitude water Cherenkov observatory (HAWC) is an instrument for the detection of high energy cosmic gamma-rays. Its predecessor Milagro has successfully proven that the water Cherenkov technology for gamma-ray astronomy is a useful technique. HAWC is currently under construction at Sierra Negra in Mexico at an altitude of 4100 m and will include several improvements compared to Milagro. Two complementary DAQ systems of the HAWC detector allow for the observation of a large fraction of the sky with a very high duty cycle and independent of environmental conditions. HAWC will observe the gamma-ray sky from about 100 GeV up to 100 TeV. Also the cosmic ray flux anisotropy on different angular length scales is object of HAWC science. Because of HAWC's large effective area and field of view, we describe its prospects to observe gamma-ray bursts (GRBs) as an example for transient sources.

  20. Reverse surface-polariton cherenkov radiation

    PubMed Central

    Tao, Jin; Wang, Qi Jie; Zhang, Jingjing; Luo, Yu

    2016-01-01

    The existence of reverse Cherenkov radiation for surface plasmons is demonstrated analytically. It is shown that in a metal-insulator-metal (MIM) waveguide, surface plasmon polaritons (SPPs) excited by an electron moving at a speed higher than the phase velocity of SPPs can generate Cherenkov radiation, which can be switched from forward to reverse direction by tuning the core thickness of the waveguide. Calculations are performed in both frequency and time domains, demonstrating that a radiation pattern with a backward-pointing radiation cone can be achieved at small waveguide core widths, with energy flow opposite to the wave vector of SPPs. Our study suggests the feasibility of generating and steering electron radiation in simple plasmonic systems, opening the gate for various applications such as velocity-selective particle detections. PMID:27477061

  1. ctools: Cherenkov Telescope Science Analysis Software

    NASA Astrophysics Data System (ADS)

    Knödlseder, Jürgen; Mayer, Michael; Deil, Christoph; Buehler, Rolf; Bregeon, Johan; Martin, Pierrick

    2016-01-01

    ctools provides tools for the scientific analysis of Cherenkov Telescope Array (CTA) data. Analysis of data from existing Imaging Air Cherenkov Telescopes (such as H.E.S.S., MAGIC or VERITAS) is also supported, provided that the data and response functions are available in the format defined for CTA. ctools comprises a set of ftools-like binary executables with a command-line interface allowing for interactive step-wise data analysis. A Python module allows control of all executables, and the creation of shell or Python scripts and pipelines is supported. ctools provides cscripts, which are Python scripts complementing the binary executables. Extensions of the ctools package by user defined binary executables or Python scripts is supported. ctools are based on GammaLib (ascl:1110.007).

  2. Particle identification via Cherenkov correlated timing

    NASA Astrophysics Data System (ADS)

    Honscheid, K.; Selen, M.; Sivertz, M.

    1994-04-01

    We describe a new particle-identification technique based on precision timing measurements to determine the Cherenkov angle of photons emitted by particles passing through a quartz radiator. A Monte Carlo simulation indicates that good π-K separation can be obtained for a large range of particle momenta and incident angles. A prototype detector to demonstrate the feasibility of the concept is under construction.

  3. Study of TOF PET using Cherenkov light

    NASA Astrophysics Data System (ADS)

    Korpar, S.; Dolenec, R.; Križan, P.; Pestotnik, R.; Stanovnik, A.

    We report on measurements of coincident 511 keV annihilation photons via detection of Cherenkov radiation in PbF2 crystals attached to a microchannel plate photomultiplier. Back to back timing resolution has been studied with segmented crystals. The detection efficiency has also been measured and compared to the simulation results. We have also searched for the optimum radiator parameters by simulating timing resolution and effciency as a function of crystal thickness and transmission cut-off.

  4. Measuring module of the Cherenkov water detector NEVOD

    NASA Astrophysics Data System (ADS)

    Kindin, V. V.; Amelchakov, M. B.; Barbashina, N. S.; Bogdanov, A. G.; Burtsev, V. D.; Chernov, D. V.; Khokhlov, S. S.; Khomyakov, V. A.; Kokoulin, R. P.; Kompaniets, K. G.; Kovylyaeva, E. A.; Kruglikova, V. S.; Ovchinnikov, V. V.; Petrukhin, A. A.; Shulzhenko, I. A.; Shutenko, V. V.; Yashin, I. I.; Zadeba, E. A.

    2015-08-01

    Quasispherical Module (QSM) of Cherenkov water detector NEVOD represents six low-noise FEU-200 photomultipliers with flat photocathodes (15 cm in diameter), oriented along the axes of orthogonal coordinate system. Such configuration allows to register Cherenkov radiation arriving from any direction with almost equal efficiency. The results of measurements of QSM characteristics in the sensitive volume of the NEVOD detector during the registration of Cherenkov radiation of single muons at different distances and angles are discussed.

  5. Air Cherenkov methods in cosmic rays: Review and some history

    NASA Astrophysics Data System (ADS)

    Lidvansky, A. S.

    2006-08-01

    Radiation first discovered by Pavel Cherenkov is used for developing a variety of methods in cosmic-ray studies. Among them, air Cherenkov methods form a separate area with several lines of research. Numerous applications of air Cherenkov radiation in studies of extensive air showers, in γ-astronomy and neutrino physics are reviewed. A tribute is given to Alexander Chudakov whose pioneer ideas and experimental skill laid foundation for the present-day progress.

  6. Roughness tolerances for Cherenkov telescope mirrors

    NASA Astrophysics Data System (ADS)

    Tayabaly, K.; Spiga, D.; Canestrari, R.; Bonnoli, G.; Lavagna, M.; Pareschi, G.

    2015-09-01

    The Cherenkov Telescope Array (CTA) is a forthcoming international ground-based observatory for very high-energy gamma rays. Its goal is to reach sensitivity five to ten times better than existing Cherenkov telescopes such as VERITAS, H.E.S.S. or MAGIC and extend the range of observation to energies down to few tens of GeV and beyond 100 TeV. To achieve this goal, an array of about 100 telescopes is required, meaning a total reflective surface of several thousands of square meters. Thence, the optimal technology used for CTA mirrors' manufacture should be both low-cost (~1000 euros/m2) and allow high optical performances over the 300-550 nm wavelength range. More exactly, a reflectivity higher than 85% and a PSF (Point Spread Function) diameter smaller than 1 mrad. Surface roughness can significantly contribute to PSF broadening and limit telescope performances. Fortunately, manufacturing techniques for mirrors are now available to keep the optical scattering well below the geometrically-predictable effect of figure errors. This paper determines first order surface finish tolerances based on a surface microroughness characterization campaign, using Phase Shift Interferometry. That allows us to compute the roughness contribution to Cherenkov telescope PSF. This study is performed for diverse mirror candidates (MAGIC-I and II, ASTRI, MST) varying in manufacture technologies, selected coating materials and taking into account the degradation over time due to environmental hazards.

  7. Time-track complementarity'' in the study of EAS longitudinal development

    SciTech Connect

    Danilova, T.V. ); Dumora, D. ); Erlykin, A.D. ); Procureur, J. )

    1993-06-15

    EAS muon production and propagation through the atmosphere were simulated. For each muon at the observation level its incidence angles and the arrival time were determined. It is shown that for large distances from EAS cores and for GeV-muons, time and track measurements could be complementary to improve the accuracy of the muon production height determination.

  8. Development of a mid-sized Schwarzschild-Couder Telescope for the Cherenkov Telescope Array

    SciTech Connect

    Cameron, Robert A.

    2012-06-28

    The Cherenkov Telescope Array (CTA) is a ground-based observatory for very high-energy (10 GeV to 100 TeV) gamma rays, planned for operation starting in 2018. It will be an array of dozens of optical telescopes, known as Atmospheric Cherenkov Telescopes (ACTs), of 8 m to 24 m diameter, deployed over an area of more than 1 square km, to detect flashes of Cherenkov light from showers initiated in the Earth's atmosphere by gamma rays. CTA will have improved angular resolution, a wider energy range, larger fields of view and an order of magnitude improvement in sensitivity over current ACT arrays such as H.E.S.S., MAGIC and VERITAS. Several institutions have proposed a research and development program to eventually contribute 36 medium-sized telescopes (9 m to 12 m diameter) to CTA to enhance and optimize its science performance. The program aims to construct a prototype of an innovative, Schwarzschild-Couder telescope (SCT) design that will allow much smaller and less expensive cameras and much larger fields of view than conventional Davies-Cotton designs, and will also include design and testing of camera electronics for the necessary advances in performance, reliability and cost. We report on the progress of the mid-sized SCT development program.

  9. 47 CFR 11.33 - EAS Decoder.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false EAS Decoder. 11.33 Section 11.33 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Equipment Requirements § 11.33 EAS Decoder. (a) An EAS Decoder must at a minimum be capable of providing the EAS monitoring functions described in § 11.52, decoding...

  10. 47 CFR 11.33 - EAS Decoder.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false EAS Decoder. 11.33 Section 11.33 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Equipment Requirements § 11.33 EAS Decoder. (a) An EAS Decoder must at a minimum be capable of providing the EAS monitoring functions described in § 11.52, decoding...

  11. 47 CFR 11.33 - EAS Decoder.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false EAS Decoder. 11.33 Section 11.33 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Equipment Requirements § 11.33 EAS Decoder. (a) An EAS Decoder must at a minimum be capable of providing the EAS monitoring functions described in § 11.52, decoding...

  12. Active optics system of the ASTRI SST-2M prototype for the Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    Gardiol, Daniele; Capobianco, Gerardo; Fantinel, Daniela; Giro, Enrico; Lessio, Luigi; Loreggia, Davide; Rodeghiero, Gabriele; Russo, Federico; Volpicelli, Antonio C.

    2014-07-01

    ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) SST-2M is an end-to-end prototype of Small Size class of Telescope for the Cherenkov Telescope Array. It will apply a dual mirror configuration to Imaging Atmospheric Cherenkov Telescopes. The 18 segments composing the primary mirror (diameter 4.3 m) are equipped with an active optics system enabling optical re-alignment during telescope slew. The secondary mirror (diameter 1.8 m) can be moved along three degrees of freedom to perform focus and tilt corrections. We describe the kinematic model used to predict the system performance as well as the hardware and software design solution that will be implemented for optics control.

  13. Cross calibration of telescope optical throughput efficiencies using reconstructed shower energies for the Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    Mitchell, A. M. W.; Parsons, R. D.; Hofmann, W.; Bernlöhr, K.

    2016-02-01

    For reliable event reconstruction of Imaging Atmospheric Cherenkov Telescopes (IACTs), calibration of the optical throughput efficiency is required. Within current facilities, this is achieved through the use of ring shaped images generated by muons. Here, a complementary approach is explored, achieving cross calibration of elements of IACT arrays through pairwise comparisons between telescopes, focussing on its applicability to the upcoming Cherenkov Telescope Array (CTA). Intercalibration of telescopes of a particular type using eventwise comparisons of shower image amplitudes has previously been demonstrated to recover the relative telescope optical responses. A method utilising the reconstructed energy as an alternative to image amplitude is presented, enabling cross calibration between telescopes of varying types within an IACT array. Monte Carlo studies for two plausible CTA layouts have shown that this calibration procedure recovers the relative telescope response efficiencies at the few per cent level.

  14. RF Cherenkov picosecond timing technique for high energy physics applications

    SciTech Connect

    Margaryan, Amur; Hashimoto, Osamu; Majewski, Stanislaw; Tang, Liguang

    2008-09-01

    The Cherenkov time-of-propagation (TOP) detector and Cherenkov time-of-flight (TOF) detector in a ?head-on? geometry based on the recently proposed time measuring technique with radio frequency (RF) phototube are considered. Results of the Monte Carlo simulations are presented.

  15. The endcap Cherenkov ring imaging detector at SLD

    SciTech Connect

    Abe, K.; Hasegawa, K.; Hawegawa, Y.; Iwasaki, Y.; Suekane, F.; Yuta, H.; Antilogus, P.; Aston, D.; Bienz, T.; Bird, F.; Dolinsky, S.

    1995-05-01

    The authors present the Cherenkov Ring Imaging Detector in the endcap regions of the SLD detector and report initial performance. The endcap CRID was completed and commissioned in 1993 and is fully operational for the 1994 run. First Cherenkov rings have been observed. The endcap CRID detectors and fluid systems are described and initial operational experience is discussed.

  16. Cherenkov detector for beam quality measurement

    NASA Astrophysics Data System (ADS)

    Orfanelli, S.

    2016-07-01

    A new detector to measure the machine induced background at larger radii has been developed and installed in the CMS experiment at the LHC. It consists of forty modules, each comprising a quartz bar read out by a photomultiplier tube. Since Cherenkov radiation is emitted in a forward cone around the charged particle trajectory, these detectors can distinguish between the arrival directions of the machine induced background and the collision products. The back-end electronics consists of a uTCA readout with excellent time resolution. The installation in the CMS is described and first commissioning measurements with the LHC beams in Run II are presented.

  17. Current state of ring imaging Cherenkov detectors

    SciTech Connect

    Coutrakon, G.B.

    1984-02-01

    This paper reviews several ring imaging Cherenkov detectors which are being used or developed to identify particles in high energy physics experiments. These detectors must have good detection efficiency for single photon-electrons and good spatial resolution over a large area. Emphasis is placed on the efficiencies and resolutions of these detectors as determined from ring imaging beam tests and other experiments. Following a brief review of the ring imaging technique, comparative evaluations are made of different forms of detectors and their respective materials.

  18. Cherenkov radiation as a serendipitous phenomenon

    NASA Astrophysics Data System (ADS)

    Kadmensky, S. G.

    2015-05-01

    A brief account is given of P A Cherenkov's Voronezh years, a period during which the future Nobel laureate in physics attended school (in the village of Novaya Chigla near Voronezh) and studied at Voronezh State University. The history of the serendipitous discovery of the radiation which was to be named after him is described and its importance for modern science is discussed. Possible modern approaches are considered to explain — without using the concept of 'cold nuclear synthesis' — some other unexpected experimental results on the nonthermonuclear fusion of light nuclei stimulated by electron beams and by laser and gamma radiations.

  19. Cherenkov-Vavilov Formulation of X Waves

    SciTech Connect

    Walker, S. C.; Kuperman, W. A.

    2007-12-14

    The field from a supersonic (or equivalently superluminal) point source in uniform motion [i.e., the Cherenkov-Vavilov (CV) effect] is shown to be equivalent to the diffractionless X-wave field. It is demonstrated that the power required to support an X wave is equivalent to the power dissipated by a CV source. In the context of the CV solution, it is clear that any supersonic or superluminal properties exhibited by X waves are purely phase effects. As a consequence, X waves cannot propagate a signal faster than the speed of waves, and thus necessarily obey the law on the finiteness of information transfer.

  20. Signal acquisition in Cherenkov-type diagnostics of electron beams within tokamak facilities

    NASA Astrophysics Data System (ADS)

    Rabiński, Marek; Jakubowski, Lech; Sadowski, Marek J.; Żebrowski, Jarosław; Jakubowski, Marcin J.; Malinowski, Karol; Mirowski, Robert

    2015-09-01

    The paper presents feasibility and design studies of Cherenkov-type probes, a development of the measuring head construction designed for different tokamak devices, and in particular the acquisition of optical signals to a data storage system. In order to lower the energy threshold of the electron detection the authors applied radiators with the highest values of the refractive index. Different radiator materials, such as aluminium nitride and CVD diamond were applied. Several versions of measuring heads and different manipulators, e.g., a movable vacuum-tight shaft or a fast-moving reciprocating probe, were manufactured and used. The practical application of the Cherenkov probes required also a consideration of spectral characteristics of optical fibres and photomultipliers. The Cherenkov radiation, as generated inside the radiators, is lead out through separate fibres (optical cables) to the atmospheric pressure side. The emitted radiation in the blue (near ultraviolet) spectrum range should be collected and delivered through appropriate optical cables to a control room, amplified within photomultipliers and recorded in a digital form. In order to investigate an electron energy distribution the multi-channel probes have also been designed and applied.

  1. Results and perspectives of cosmic ray mass composition studies with EAS arrays in the Tunka Valley

    NASA Astrophysics Data System (ADS)

    Prosin, V. V.; Budnev, N. M.; Chiavassa, A.; Dyachok, A. N.; Epimakhov, S. N.; Fenu, F.; Fomin, Yu A.; Gress, O. A.; Gress, T. I.; Kalmykov, N. N.; Karpov, N. I.; Korosteleva, E. E.; Kozhin, V. A.; Kuzmichev, L. A.; Lubsandorzhiev, B. K.; Lubsandorzhiev, N. B.; Mirgazov, R. R.; Monhoev, R. D.; Osipova, E. A.; Panasyuk, M. I.; Pankov, L. V.; Popova, E. G.; Ptuskin, V. S.; Semeney, Yu A.; Silaev, A. A.; Silaev, A. A., Jr.; Skurikhin, A. V.; Spiering, C.; Sulakov, V. P.; Sveshnikova, L. G.; Zagorodnikov, A. V.

    2016-05-01

    The study of the cosmic ray mass composition in the energy range 1016 - 1018 eV is one of the main aims of Tunka-133. This EAS Cherenkov array started data acquisition in the Tunka Valley (50 km from Lake Baikal) in autumn 2009. Tunka-133 provides a measurement of the EAS maximum depth (Xmax) with an accuracy of about 30 g/cm2 . Further mass composition analyses at the highest energies (1017 - 1018 eV) will be based on the comparison of primary energy measured by the radio method and the densities of charged particles measured by shielded and unshielded detectors. The high duty cycle of the common operation of the new scintillation array (Tunka-Grande) and the radio extension of the experiment (Tunka-REX) will provide a high statistics of events.

  2. Investigation of the energy characteristics of EAS muon component with the NEVOD-DECOR setup

    NASA Astrophysics Data System (ADS)

    Bogdanov, A. G.; Barbashina, N. S.; Dushkin, L. I.; Kindin, V. V.; Kokoulin, R. P.; Kompaniets, K. G.; Mannocchi, G.; Petrukhin, A. A.; Romanenkova, E. V.; Saavedra, O.; Trinchero, G.; Khomyakov, V. A.; Khokhlov, S. S.; Chernov, D. V.; Shutenko, V. V.; Yurina, E. A.; Yashin, I. I.

    2016-02-01

    Investigations of the energy characteristics of muon component with the increase of the primary cosmic rays energy can be a key to solving ‘muon puzzle’ - the problem of excess of EAS muons (observed in several experiments at high - ALEPH, DELPHI - and ultrahigh energies - DECOR, Pierre Auger Observatory) in comparison with the expected flux. The measurements results of the energy deposit of inclined muon bundles in water depending on the zenith angle and the local density of muons are presented. As a measure of the energy deposit, the total number of photoelectrons registered by PMTs of the Cherenkov water calorimeter NEVOD was used. The local density of muons, which gives an estimate of the energy of primary particles was obtained from the data of coordinate-tracking detector DECOR. The experimental data are compared with the results of calculations based on simulations of the muon component of EAS by means of the CORSIKA code.

  3. The Potential of Spaced-based High-Energy Neutrino Measurements via the Airshower Cherenkov Signal

    NASA Technical Reports Server (NTRS)

    Krizmanic, John F.; Mitchell, John W.

    2011-01-01

    Future space-based experiments, such as (Orbiting Wide-angle Light Collectors (OWL) and JEM-EUSO, view large atmospheric and terrestrial neutrino targets. With energy thresholds slightly above 10(exp 19) eV for observing airshowers via air fluorescence, the potential for observing the cosmogenic neutrino flux associated with the GZK effect is limited. However, the forward Cherenkov signal associated with the airshower can be observed at much lower energies. A simulation was developed to determine the Cherenkov signal strength and spatial extent at low-Earth orbit for upward-moving airshowers. A model of tau neutrino interactions in the Earth was employed to determine the event rate of interactions that yielded a tau lepton which would induce an upward-moving airshower observable by a space-based instrument. The effect of neutrino attenuation by the Earth forces the viewing of the Earth's limb to observe the vT-induced Cherenkov airshower signal at above the OWL Cherenkov energy threshold of approximately 10(exp 16.5) eV for limb-viewed events. Furthermore, the neutrino attenuation limits the effective terrestrial neutrino target area to approximately 3 x 10(exp 5) square km at 10(exp 17) eV, for an orbit of 1000 km and an instrumental full Field-of-View of 45 deg. This translates into an observable cosmogenic neutrino event rate of approx. l/year based upon two different models of the cosmogenic neutrino flux, assuming neutrino oscillations and a 10% duty cycle for observation.

  4. The High Altitude Water Cherenkov Observatory

    NASA Astrophysics Data System (ADS)

    Mostafa, Miguel; HAWC Collaboration

    2016-03-01

    The High Altitude Water Cherenkov (HAWC) Observatory is a continuously operated, wide field of view experiment comprised of an array of 300 water Cherenkov detectors (WCDs) to study transient and steady emission of TeV gamma and cosmic rays. Each 200000 l WCD is instrumented with 4 PMTs providing charge and timing information. The array covers ~22000 m2 at an altitude of 4100 m a.s.l. inside the Pico de Orizaba national park in Mexico. The high altitude, large active area, and optical isolation of the PMTs allows us to reliably estimate the energy and determine the arrival direction of gamma and cosmic rays with significant sensitivity over energies from several hundred GeV to a hundred TeV. Continuously observing 2 / 3 of the sky every 24 h, HAWC plays a significant role as a survey instrument for multi-wavelength studies. The performance of HAWC makes possible the detection of both transient and steady emissions, the study of diffuse emission and the measurement of the spectra of gamma-ray sources at TeV energies. HAWC is also sensitive to the emission from GRBs above 100 GeV. I will highlight the results from the first year of operation of the full HAWC array, and describe the ongoing site work to expand the array by a factor of 4 to explore the high energy range.

  5. The High Altitude Water Cherenkov (HAWC) Observatory

    NASA Astrophysics Data System (ADS)

    Springer, Wayne

    2014-06-01

    The High Altitude Water Cherenkov (HAWC) observatory is a continuously operated, wide field of view detector based upon a water Cherenkov technology developed by the Milagro experiment. HAWC observes, at an elevation of 4100 m on Sierra Negra Mountain in Mexico, extensive air showers initiated by gamma and cosmic rays. The completed detector will consist of 300 closely spaced water tanks each instrumented with four photomultiplier tubes that provide timing and charge information used to reconstruct energy and arrival direction. HAWC has been optimized to observe transient and steady emission from point as well as diffuse sources of gamma rays in the energy range from several hundred GeV to several hundred TeV. Studies in solar physics as well as the properties of cosmic rays will also be performed. HAWC has been making observations at various stages of deployment since completion of 10% of the array in summer 2012. A discussion of the detector design, science capabilities, current construction/commissioning status, and first results will be presented...

  6. The High-Altitude Water Cherenkov Observatory

    NASA Astrophysics Data System (ADS)

    Mostafá, Miguel A.

    2014-10-01

    The High-Altitude Water Cherenkov (HAWC) observatory is a large field of view, continuously operated, TeV γ-ray experiment under construction at 4,100 m a.s.l. in Mexico. The HAWC observatory will have an order of magnitude better sensitivity, angular resolution, and background rejection than its predecessor, the Milagro experiment. The improved performance will allow us to detect both the transient and steady emissions, to study the Galactic diffuse emission at TeV energies, and to measure or constrain the TeV spectra of GeV γ-ray sources. In addition, HAWC will be the only ground-based instrument capable of detecting prompt emission from γ-ray bursts above 50 GeV. The HAWC observatory will consist of an array of 300 water Cherenkov detectors (WCDs), each with four photomultiplier tubes. This array is currently under construction on the flanks of the Sierra Negra volcano near the city of Puebla, Mexico. The first 30 WCDs (forming an array approximately the size of Milagro) were deployed in Summer 2012, and 100 WCDs will be taking data by May, 2013. We present in this paper the motivation for constructing the HAWC observatory, the status of the deployment, and the first results from the constantly growing array.

  7. 47 CFR 11.18 - EAS Designations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false EAS Designations. 11.18 Section 11.18 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) General § 11.18 EAS Designations. (a) National Primary (NP) is a source of EAS Presidential messages. (b) Local Primary (LP) is...

  8. 47 CFR 11.18 - EAS Designations.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false EAS Designations. 11.18 Section 11.18 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) General § 11.18 EAS Designations. (a) National Primary (NP) is a source of EAS Presidential messages. (b) Local Primary (LP) is...

  9. 47 CFR 11.18 - EAS Designations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false EAS Designations. 11.18 Section 11.18 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) General § 11.18 EAS Designations. (a) National Primary (NP) is a source of EAS Presidential messages. (b) Local Primary (LP) is...

  10. 47 CFR 11.31 - EAS protocol.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false EAS protocol. 11.31 Section 11.31....31 EAS protocol. (a) The EAS uses a four part message for an emergency activation of the EAS. The... protocol, including any codes, must not be amended, extended or abridged without FCC authorization. The...

  11. Progress in Cherenkov ring imaging. Part 2: Identification of charged hadrons at 200 GeV/c

    NASA Astrophysics Data System (ADS)

    Mangeot, Ph.; Coutrakon, G.; Hubbard, J. R.; M´, J.; Tichit, J.; Zadra, A.; Bouclier, R.; Charpak, G.; Million, J.; Peisert, A.; Santiard, J. C.; Sauli, F.; Brown, C. N.; Finley, D.; Glass, H.; Kirz, J.; McCarthy, R. L.

    1983-10-01

    We have used a ring-imaging Cherenkov detector to separate π's, K's, and antiprotons in a 200 GeV/ c beam at Fermilab. This device was built as a prototype for a large-aperture counter now in operation in Fermilab experiment E605. The radiator consisted of 8 m of atmospheric-pressure helium gas. The photon detector was a multistep proportional chamber. Cherenkov photons near 8 eV were detected by photoionization of triethylamine (TEA) vapor in the chamber. An average of 2.5 to 2.7 Cherenkov photons were observed per event, corresponding to a figure of merit N 0 ⋍ 45 per cm. A single-photon radius uncertainty of 0.47 mm was obtained with a helium/TEA/CH 4 gas mixture in the photon detector. The rms uncertainty in the determination of the Cherenkov angle was ΔΘ c/Θ max = 0.006 , corresponding to one-standard-deviation π/K separation at 500 GeV/ c. At 200 GeV/ c, the particle identification efficiency in a beam containing 95.2% π -, 4.3% K -, and 0.5% antiprotons was 92% for the π's, 83% for the K's, and 90% for the antiprotons.

  12. Quenching the scintillation in CF4 Cherenkov gas radiator

    NASA Astrophysics Data System (ADS)

    Blake, T.; D`Ambrosio, C.; Easo, S.; Eisenhardt, S.; Fitzpatrick, C.; Forty, R.; Frei, C.; Gibson, V.; Gys, T.; Harnew, N.; Hunt, P.; Jones, C. R.; Lambert, R. W.; Matteuzzi, C.; Muheim, F.; Papanestis, A.; Perego, D. L.; Piedigrossi, D.; Plackett, R.; Powell, A.; Topp-Joergensen, S.; Ullaland, O.; Websdale, D.; Wotton, S. A.; Wyllie, K.

    2015-08-01

    CF4 is used as a Cherenkov gas radiator in one of the Ring Imaging Cherenkov detectors at the LHCb experiment at the CERN Large Hadron Collider. CF4 is well known to have a high scintillation photon yield in the near and far VUV, UV and in the visible wavelength range. A large flux of scintillation photons in our photon detection acceptance between 200 and 800 nm could compromise the particle identification efficiency. We will show that this scintillation photon emission system can be effectively quenched, consistent with radiationless transitions, with no significant impact on the photons resulting from Cherenkov radiation.

  13. Cherenkov neutron detector for fusion reaction and runaway electron diagnostics.

    PubMed

    Cheon, MunSeong; Kim, Junghee

    2015-08-01

    A Cherenkov-type neutron detector was newly developed and neutron measurement experiments were performed at Korea Superconducting Tokamak Advanced Research. It was shown that the Cherenkov neutron detector can monitor the time-resolved neutron flux from deuterium-fueled fusion plasmas. Owing to the high temporal resolution of the detector, fast behaviors of runaway electrons, such as the neutron spikes, could be observed clearly. It is expected that the Cherenkov neutron detector could be utilized to provide useful information on runaway electrons as well as fusion reaction rate in fusion plasmas. PMID:26329194

  14. Cherenkov neutron detector for fusion reaction and runaway electron diagnostics

    SciTech Connect

    Cheon, MunSeong Kim, Junghee

    2015-08-15

    A Cherenkov-type neutron detector was newly developed and neutron measurement experiments were performed at Korea Superconducting Tokamak Advanced Research. It was shown that the Cherenkov neutron detector can monitor the time-resolved neutron flux from deuterium-fueled fusion plasmas. Owing to the high temporal resolution of the detector, fast behaviors of runaway electrons, such as the neutron spikes, could be observed clearly. It is expected that the Cherenkov neutron detector could be utilized to provide useful information on runaway electrons as well as fusion reaction rate in fusion plasmas.

  15. Cherenkov Light-based Beam Profiling for Ultrarelativistic Electron Beams

    SciTech Connect

    Adli, E.; Gessner, S. J.; Corde, S.; Hogan, M. J.; Bjerke, H. H.

    2015-02-09

    We describe a beam profile monitor design based on Cherenkov light emitted from a charged particle beam in an air gap. The main components of the profile monitor are silicon wafers used to reflect Cherenkov light onto a camera lens system. The design allows for measuring large beam sizes, with large photon yield per beam charge and excellent signal linearity with beam charge. Furthermore, the profile monitor signal is independent of the particle energy for ultrarelativistic particles. Different design and parameter considerations are discussed. A Cherenkov light-based profile monitor has been installed at the FACET User Facility at SLAC. Finally, we report on the measured performance of this profile monitor.

  16. Lateral distribution on charged particles in EAS

    NASA Technical Reports Server (NTRS)

    Dedenko, L. G.; Sulakov, V. F.; Kulikov, G. V.; Solovjeva, V. I.

    1985-01-01

    Lateral distribution of charged particles which allow for the finiteness of energy gamma-quanta, the inhomogeneity of the atmosphere and the experimental selection of EAS are needed to interpret experimental data. The effects of finiteness of energy of gamma-quanta which produce the partial electron-photon cascades were considered by substituting K R sub m instead of R sub m in NKG approximation where K was found to be 0.56 from comparison with the experimental data. New results on the lateral distribution of electrons in the partial cascades from gamma-quanta were obtained. It is shown that the coefficient K can be regarded as a constant. The last approximation of K was found to be most adequate when compared with the experimental data. The inhomogeneity of the atmosphere, muons and experimental selection are considered. The calculation of Ne are extended from 100,000 to 10 million for sea level and for Akeno level.

  17. EA Shuttle Document Retention Effort

    NASA Technical Reports Server (NTRS)

    Wagner, Howard A.

    2010-01-01

    This slide presentation reviews the effort of code EA at Johnson Space Center (JSC) to identify and acquire databases and documents from the space shuttle program that are adjudged important for retention after the retirement of the space shuttle.

  18. Nonlinear theory of a plasma Cherenkov maser

    SciTech Connect

    Choi, J.S.; Heo, E.G.; Choi, D.I.

    1995-12-31

    The nonlinear saturation state in a plasma Cherenkov maser (PCM) propagating the intense relativistic electron beam through a circular waveguide partially filled with a dense annular plasma, is analyzed from the nonlinear formulation based on the cold fluid-Maxwell equations. We obtain the nonlinear efficiency and the final operation frequency under consideration of the effects of the beam current, the beam energy and the slow wave structure. We show that the saturation mechanism of a PCM instablity is a close correspondence in that of the relativistic two stream instability by the coherent trapping of electrons in a single most-ustable wave. And the optimal conditions in PCM operation are also obtained from performing our nonliear analysis together with computer simulations.

  19. Cherenkov radiation from short relativistic bunches: general approach.

    PubMed

    Baturin, S S; Kanareykin, A D

    2014-11-21

    In recent years new interest in Cherenkov radiation has arisen based on progress in its new applications like biomedical imaging, photonic structures, metamaterials, and beam physics. These new applications require Cherenkov radiation theory of short bunches to be extended to rather more complicated media and structures than considered originally. We present a new general approach to the analysis of Cherenkov fields and loss factors for relativistic short bunches in arbitrary slow wave guiding systems. This new formalism is obtained by considering a general integral relation that allows calculation of the fields in the vicinity of the charge. The proposed approach dramatically simplifies simulations using analytical fields near the moving source of Cherenkov radiation. PMID:25479498

  20. Energy calibration of Cherenkov Telescopes using GLAST data

    SciTech Connect

    Bastieri, D.; Busetto, G.; Piano, G.; Rando, R.; Saggion, A.; De Angelis, A.; Longo, F.

    2007-07-12

    We discuss the possibility of using the observations by GLAST of steady gamma sources, as the Crab Nebula and some selected AGNs, to calibrate the Imaging Air Cherenkov Telescopes (IACT) and improve their energy resolution, in particular. We show that at around 100 GeV, exploiting the features in the spectrum of the Crab Nebula, the absolute energy calibration uncertainty of Cherenkov telescopes can be reduced to < 10%.

  1. CHERCAM: The Cherenkov imager of the CREAM experiment

    NASA Astrophysics Data System (ADS)

    Sallaz-Damaz, Y.; Barrau, A.; Bazer-Bachi, R.; Bourrion, O.; Bouvier, J.; Boyer, B.; Buénerd, M.; Derome, L.; Eraud, L.; Foglio, R.; Gallin-Martel, L.; Ganel, O.; Han, J. H.; Kim, K. C.; Lee, M. H.; Lutz, L.; Mangin-Brinet, M.; Malinine, A.; Menchaca-Rocha, A.; Périé, J. N.; Putze, A.; Scordilis, J.-P.; Seo, E. S.; Walpole, P.; Yoo, J. H.; Yoon, Y. S.; Zinn, S. Y.

    2008-09-01

    A Cherenkov imager, CHERCAM (CHERenkov CAMera), has been designed and built for the CREAM (Cosmic-Ray Energetic and Mass) balloon-borne experiment. The instrument will perform charge measurements of nuclear cosmic-ray over a range extending from proton to iron. It will achieve individual charge separation of the elements over this range [M. Buénerd, et al., in: 28th ICRC, Tsukuba, Japan, OG 1.5, 2003, p. 2157. [2

  2. Electron Beam Diagnostics using Coherent Cherenkov Radiation in Aerogel

    SciTech Connect

    Tikhoplav, R.; Knyazik, A.; Rosenzweig, J. B.; Ruelas, M.

    2009-01-22

    The use of coherent Cherenkov radiation as a diagnostic tool for longitudinal distribution of an electron beam is studied in this paper. Coherent Cherenkov radiation is produced in an aerogel with an index of refraction close to unity. An aerogel spectral properties are experimentally studied and analyzed. This method will be employed for the helical IFEL bunching experiment at Neptune linear accelerator facility at UCLA.

  3. Orthogonal Cherenkov sound in spin-orbit coupled systems

    NASA Astrophysics Data System (ADS)

    Smirnov, Sergey

    2015-06-01

    Conventionally the Cherenkov sound is governed by orbital degrees of freedom and is excited by supersonic particles. Additionally, it usually has a forward nature with a conic geometry known as the Cherenkov cone whose axis is oriented along the supersonic particle motion. Here we predict Cherenkov sound of a unique nature entirely resulting from the electronic spin degree of freedom and demonstrate a fundamentally distinct Cherenkov effect originating from essentially subsonic electrons in two-dimensional gases with both Bychkov-Rashba and Dresselhaus spin-orbit interactions. Specifically, we show that the axis of the conventional forward Cherenkov cone gets a nontrivial quarter-turn and at the same time the sound distribution strongly localizes around this rotated axis being now orthogonal to the subsonic particle motion. Apart from its fundamentally appealing nature, the orthogonal Cherenkov sound could have applications in planar semiconductor technology combining spin and acoustic phenomena to develop, e.g., acoustic amplifiers or sound sources with a flexible spin dependent orientation of the sound propagation.

  4. Cherenkov imaging and biochemical sensing in vivo during radiation therapy

    NASA Astrophysics Data System (ADS)

    Zhang, Rongxiao

    While Cherenkov emission was discovered more than eighty years ago, the potential applications of imaging this during radiation therapy have just recently been explored. With approximately half of all cancer patients being treated by radiation at some point during their cancer management, there is a constant challenge to ensure optimal treatment efficiency is achieved with maximal tumor to normal tissue therapeutic ratio. To achieve this, the treatment process as well as biological information affecting the treatment should ideally be effective and directly derived from the delivery of radiation to the patient. The value of Cherenkov emission imaging was examined here, primarily for visualization of treatment monitoring and then secondarily for Cherenkov-excited luminescence for tissue biochemical sensing within tissue. Through synchronized gating to the short radiation pulses of a linear accelerator (200Hz & 3 micros pulses), and applying a gated intensified camera for imaging, the Cherenkov radiation can be captured near video frame rates (30 frame per sec) with dim ambient room lighting. This procedure, sometimes termed Cherenkoscopy, is readily visualized without affecting the normal process of external beam radiation therapy. With simulation, phantoms and clinical trial data, each application of Cherenkoscopy was examined: i) for treatment monitoring, ii) for patient position monitoring and motion tracking, and iii) for superficial dose imaging. The temporal dynamics of delivered radiation fields can easily be directly imaged on the patient's surface. Image registration and edge detection of Cherenkov images were used to verify patient positioning during treatment. Inter-fraction setup accuracy and intra-fraction patient motion was detectable to better than 1 mm accuracy. Cherenkov emission in tissue opens up a new field of biochemical sensing within the tissue environment, using luminescent agents which can be activated by this light. In the first study of

  5. Expected performance of the ASTRI mini-array in the framework of the Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    Di Pierro, F.; Bigongiari, C.; Stamerra, A.; Vallania, P.; ASTRI Collaboration; CTA Consortium, the

    2016-05-01

    The Cherenkov Telescope Array (CTA) Observatory is a world-wide project for the ground-based study of the sources of the highest energy photons. By adopting telescopes of three different size categories it will cover the wide energy range from tens of GeV up to hundreds of TeV, limited only by the source physical properties and the gamma absorption by the extragalactic background light. The full sky coverage will be assured by two arrays, one in each hemisphere. An array of small size telescopes (SSTs), covering the highest energy region (3-100 TeV), the region most flux limited for current imaging atmospheric Cherenkov telescopes, is planned to be deployed at the southern CTA site in the first phase of the CTA project. The ASTRI collaboration has developed a prototype of a dual mirror SST equipped with a SiPM-based focal plane (ASTRI SST-2M) and has proposed to install a mini-array of nine of such telescopes at the CTA southern site (the ASTRI mini-array). In order to study the expected performance and the scientific capabilities of different telescope configurations, full Monte Carlo (MC) simulations of the shower development in the atmosphere for both gammas and hadronic background have been performed, followed by detailed simulations of the telescopes. In this work the expected performance of the ASTRI mini-array in terms of sensitivity, angular and energy resolution are presented and discussed.

  6. Construction of prototype two-mirror Schwartzchild-Couder Imaging Air Cherenkov Telescope (IACT) for VHE gamma-ray astronomy

    NASA Astrophysics Data System (ADS)

    Kieda, David; CTA-US Collaboration Collaboration

    2016-03-01

    Next generation ground-based VHE gamma-ray observatories such as the Cherenkov Telescope Array (CTA) will employ an array of different sized IACTs distributed across square kilometer areas. During 2015-2016, the CTA-US collaboration is constructing a prototype 9.6 m primary diameter Schwartzchild-Couder IACT (SCT) at the FL Whipple Observatory, Amado, AZ USA. The two-mirror SCT design provides 8 degree field of view with 0.067 degree pixel size. The SCT uses a high resolution (11,328 pixel) Silicon PhotoMultiplier (SiPM) camera to record atmospheric Cherenkov light images generated by gamma-ray and cosmic ray primaries. Incorporation of SCT telescopes into a CTA-type observatory can provide superior angular resolution (30 % improvement) and point source sensitivity (30-50 %). In this talk, I will describe the capabilities of the SCT telescope, and the construction and commissioning of the prototype SCT telescope during 2016.

  7. Sensivity studies for the Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    Collado, Tarek Hassan

    2015-06-01

    Since the creation of the first telescope in the 17th century, every major discovery in astrophysics has been the direct consequence of the development of novel observation techniques, opening new windows in the electromagnetic spectrum. After Karl Jansky discovered serendipitously the first radio source in 1933, Grote Reber built the first parabolic radio telescope in his backyard, planting the seed of a whole new field in astronomy. Similarly, new technologies in the 1950s allowed the establishment of other fields, such as the infrared, ultraviolet or the X-rays. The highest energy end of the electromagnetic spectrum, the γ-ray range, represents the last unexplored window for astronomers and should reveal the most extreme phenomena that take place in the Universe. Given the technical complexity of γ-ray detection and the extremely relative low fluxes, γ-ray astronomy has undergone a slower development compared to other wavelengths. Nowadays, the great success of consecutive space missions together with the development and refinement of new detection techniques from the ground, has allowed outstanding scientific results and has brought gamma-ray astronomy to a worthy level in par with other astronomy fields. This work is devoted to the study and improvement of the future Cherenkov Telescope Array (CTA), the next generation of ground based γ-ray detectors, designed to observe photons with the highest energies ever observed from cosmic sources.

  8. Detecting new very light bosons by Cherenkov telescopes

    SciTech Connect

    Roncadelli, Marco; De Angelis, Alessandro; Mansutti, Oriana; Persic, Massimo

    2010-03-26

    A generic prediction of several extensions of the Standard Model of elementary-particle interactions is the existence of axion-like particles (ALPs), namely very light spin-zero bosons characterized by a two-photon coupling. While elusive in laboratory experiments, ALPs can give rise to observable astrophysical effects for their relevant parameters in experimentally allowed ranges. We show that the unexpectedly low opacity of the Universe inferred by the Imaging Atmospheric Cherenkov Telescopes since 2006 from blazar observations above 100 GeV can be explained naturally within the De Angelis, Roncadelli and Mansutti--hereafter DARMA--scenario, namely in terms of photon-ALP oscillations occurring in extragalactic magnetic fields. We work out the implications of the DARMA scenario for the VHE gamma-ray spectra of blazars by contemplating all of them at once, so that the emitted GAMMA{sub em} and observed GAMMA{sub obs} spectral indices can be correlated. We demonstrate that by assuming the same nominal value GAMMA{sub em}approx =2.4 for all VHE blazars, the predicted observed spectral index GAMMA{sub obs}{sup DARMA} actually fits all observations. Moreover, GAMMA{sub obs}{sup DARMA} becomes independent of redshift for sufficiently far-away sources. Our prediction can be tested with the satellite-borne Fermi/LAT detector as well as with the ground-based IACTs H.E.S.S., MAGIC, CANGAROO III, VERITAS and the Extensive Air Shower arrays ARGO-YBJ and MILAGRO.

  9. A versatile digital camera trigger for telescopes in the Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    Schwanke, U.; Shayduk, M.; Sulanke, K.-H.; Vorobiov, S.; Wischnewski, R.

    2015-05-01

    This paper describes the concept of an FPGA-based digital camera trigger for imaging atmospheric Cherenkov telescopes, developed for the future Cherenkov Telescope Array (CTA). The proposed camera trigger is designed to select images initiated by the Cherenkov emission of extended air showers from very-high energy (VHE, E > 20 GeV) photons and charged particles while suppressing signatures from background light. The trigger comprises three stages. A first stage employs programmable discriminators to digitize the signals arriving from the camera channels (pixels). At the second stage, a grid of low-cost FPGAs is used to process the digitized signals for camera regions with 37 pixels. At the third stage, trigger conditions found independently in any of the overlapping 37-pixel regions are combined into a global camera trigger by few central FPGAs. Trigger prototype boards based on Xilinx FPGAs have been designed, built and tested and were shown to function properly. Using these components a full camera trigger with a power consumption and price per channel of about 0.5 W and 19 €, respectively, can be built. With the described design the camera trigger algorithm can take advantage of pixel information in both the space and the time domain allowing, for example, the creation of triggers sensitive to the time-gradient of a shower image; the time information could also be exploited to online adjust the time window of the acquisition system for pixel data. Combining the results of the parallel execution of different trigger algorithms (optimized, for example, for the lowest and highest energies, respectively) on each FPGA can result in a better response over all photons energies (as demonstrated by Monte Carlo simulation in this work).

  10. INSTRUMENTS AND METHODS OF INVESTIGATION: Vavilov-Cherenkov amplifiers with irregular electrodynamic structures

    NASA Astrophysics Data System (ADS)

    Gulyaev, Yurii V.; Kravchenko, Viktor F.; Kuraev, Aleksandr A.

    2004-06-01

    Optimal control theory-based methods for improving the efficiency of Cherenkov microwave amplifiers with irregular electrodynamic structures are reviewed. The physics of optimal processes in amplifiers and oscillators with Cherenkov- and combined-type interactions is discussed.

  11. Detection of tau neutrinos by imaging air Cherenkov telescopes

    NASA Astrophysics Data System (ADS)

    Góra, D.; Bernardini, E.

    2016-09-01

    This paper investigates the potential to detect tau neutrinos in the energy range of 1-1000 PeV searching for very inclined showers with imaging Cherenkov telescopes. A neutrino induced tau lepton escaping from the Earth may decay and initiate an air shower which can be detected by a fluorescence or Cherenkov telescope. We present here a study of the detection potential of Earth-skimming neutrinos taking into account neutrino interactions in the Earth crust, local matter distributions at various detector sites, the development of tau-induced showers in air and the detection of Cherenkov photons with IACTs. We analyzed simulated shower images on the camera focal plane and implemented generic reconstruction chains based on Hillas parameters. We find that present IACTs can distinguish air showers induced by tau neutrinos from the background of hadronic showers in the PeV-EeV energy range. We present the neutrino trigger efficiency obtained for a few configurations being considered for the next-generation Cherenkov telescopes, i.e. the Cherenkov Telescope Array. Finally, for a few representative neutrino spectra expected from astrophysical sources, we compare the expected event rates at running IACTs to what is expected for the dedicated IceCube neutrino telescope.

  12. Characteristics of Cherenkov radiation in naturally occurring ice

    NASA Astrophysics Data System (ADS)

    Mikkelsen, R. E.; Poulsen, T.; Uggerhøj, U. I.; Klein, S. R.

    2016-03-01

    We revisit the theory of Cherenkov radiation in uniaxial crystals. Historically, a number of flawed attempts have been made at explaining this radiation phenomenon, and a consistent error-free description is nowhere available. We apply our calculation to a large modern day telescope—IceCube. Located in Antarctica, this detector makes use of the naturally occurring ice as a medium to generate Cherenkov radiation. However, due to the high pressure at the depth of the detector site, large volumes of hexagonal ice crystals are formed. We calculate how this affects the Cherenkov radiation yield and angular dependence. We conclude that the effect is small, at most about a percent, and would only be relevant in future high-precision instruments like e.g. Precision IceCube Next Generation Upgrade (PINGU). For radio-Cherenkov experiments which use the presence of a clear Cherenkov cone to determine the arrival direction, any variation in emission angle will directly and linearly translate into a change in apparent neutrino direction. In closing, we also describe a simple experiment to test this formalism and calculate the impact of anisotropy on light yields from lead tungstate crystals as used, for example, in the CMS calorimeter at the CERN LHC.

  13. Improved Detection of Cherenkov Radiation using Wavelength-Shifting Paints

    NASA Astrophysics Data System (ADS)

    Schmookler, Barak; Ou, Longwu

    2014-03-01

    Photomultiplier Tubes (PMTs) are often used to detect Cherenkov radiation in accelerator-based physics experiments. Since the Cherenkov spectrum is inversely proportional to the square of the photon's wavelength, PMTs with relatively good quantum efficiencies in the ultraviolet region can produce on average a higher number of photoelectrons. The application of certain paints, which absorb light at ultraviolet wavelengths and emit in the visible spectrum, to the surface of some PMTs allows for better sampling of the Cherenkov spectrum. The effects of various wavelength-shifting (WLS) paints designed by Eljen Technologies were tested on ET Enterprises, Model: 9390KB PMTs. Using a 106Ru β-source, Cherenkov light was produced in disks of fused silica. The charge spectrums of the PMTs were measured before and after application of the paint. The average number of photoelectrons produced from the Cherenkov radiation could be determined by knowing the value of the single-photoelectron peak and the mean of the charge spectrum. Four paints were tested, and the gain in the number photoelectrons produced varied from 10-35% for the different paints. Work Conducted at Thomas Jefferson National Accelerator Facility.

  14. Separation of scintillation and Cherenkov lights in linear alkyl benzene

    NASA Astrophysics Data System (ADS)

    Li, Mohan; Guo, Ziyi; Yeh, Minfang; Wang, Zhe; Chen, Shaomin

    2016-09-01

    To separate scintillation and Cherenkov lights in water-based liquid scintillator detectors is a desired feature for future neutrino and proton decay experiments. Linear alkyl benzene (LAB) is one important ingredient of a water-based liquid scintillator currently under development. In this paper we report on the separation of scintillation and Cherenkov lights observed in an LAB sample. The rise and decay times of the scintillation light are measured to be (7.7 ± 3.0) ns and (36.6 ± 2.4) ns , respectively, while the full width [-3σ, 3σ] of the Cherenkov light is 12 ns and is dominated by the time resolution of the photomultiplier tubes. The scintillation light yield was measured to be (1.01 ± 0.12) ×103 photons / MeV .

  15. Spin-Cherenkov effect and magnonic Mach cones

    NASA Astrophysics Data System (ADS)

    Yan, Ming; Kákay, Attila; Andreas, Christian; Hertel, Riccardo

    2013-12-01

    We report on the Cherenkov-type excitation of spin waves (SWs) in ferromagnets. Our micromagnetic simulations show that a localized magnetic field pulse moving sufficiently fast along the surface of a ferromagnet generates a SW boom, with a Mach-type cone of propagating wave fronts. The SWs are formed when the velocity of the source exceeds the propagation speed of SWs. Unlike the single cone of the usual Cherenkov effect, we find that the magnetic Mach cone consists of two wave fronts with different wave numbers. In patterned thin strips, this magnetic analog of the Cherenkov effect should enable the excitation of SWs with well-defined and velocity-dependent frequency. It thereby provides a promising route towards tunable SW generation, with important potential for applications in magnonic devices.

  16. Cherenkov Light-based Beam Profiling for Ultrarelativistic Electron Beams

    DOE PAGESBeta

    Adli, E.; Gessner, S. J.; Corde, S.; Hogan, M. J.; Bjerke, H. H.

    2015-02-09

    We describe a beam profile monitor design based on Cherenkov light emitted from a charged particle beam in an air gap. The main components of the profile monitor are silicon wafers used to reflect Cherenkov light onto a camera lens system. The design allows for measuring large beam sizes, with large photon yield per beam charge and excellent signal linearity with beam charge. Furthermore, the profile monitor signal is independent of the particle energy for ultrarelativistic particles. Different design and parameter considerations are discussed. A Cherenkov light-based profile monitor has been installed at the FACET User Facility at SLAC. Finally,more » we report on the measured performance of this profile monitor.« less

  17. Quantitative Cherenkov emission spectroscopy for tissue oxygenation assessment

    PubMed Central

    Axelsson, Johan; Glaser, Adam K.; Gladstone, David J.; Pogue, Brian W.

    2012-01-01

    Measurements of Cherenkov emission in tissue during radiation therapy are shown to enable estimation of hemoglobin oxygen saturation non-invasively, through spectral fitting of the spontaneous emissions from the treated tissue. Tissue oxygenation plays a critical role in the efficacy of radiation therapy to kill tumor tissue. Yet in-vivo measurement of this has remained elusive in routine use because of the complexity of oxygen measurement techniques. There is a spectrally broad emission of Cherenkov light that is induced during the time of irradiation, and as this travels through tissue from the point of the radiation deposition, the tissue absorption and scatter impart spectral changes. These changes can be quantified by diffuse spectral fitting of the signal. Thus Cherenkov emission spectroscopy is demonstrated for the first time quantitatively in vitro and qualitatively in vivo, and has potential for real-time online tracking of tissue oxygen during radiation therapy when fully characterized and developed. PMID:22418319

  18. The possibilities of Cherenkov telescopes to perform cosmic-ray muon imaging of volcanoes

    NASA Astrophysics Data System (ADS)

    Carbone, Daniele; Catalano, Osvaldo; Cusumano, Giancarlo; Del Santo, Melania; Maccarone, Maria Concetta; Mineo, Teresa; Pareschi, Giovanni; Vercellone, Stefano; Zuccarello, Luciano

    2016-04-01

    atmospheric muons, that is needed to asses a reference model of the through-target integrated flux. Here we describe our plans for the production of a Cherenkov telescope with suitable characteristics for installation in the summit zone of Etna volcano.

  19. The glass cold-shaping technology for the mirrors of the Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    Canestrari, Rodolfo; Bonnoli, Giacomo; Crimi, Giuseppe; Fiorini, Mauro; Giro, Enrico; La Palombara, Nicola; Pareschi, Giovanni; Perri, Luca; Rodeghiero, Gabriele; Sironi, Giorgia; Stringhetti, Luca; Toso, Giorgio; Pelliciari, Carlo

    2014-07-01

    The next generation of imaging atmospheric Cherenkov telescopes will require the production of thousands of mirror segments; an unprecedented amount of optical surface. To accomplish this, the Italian Istituto Nazionale di AstroFisica (INAF) has recently developed a successful technique. This method, called glass cold-shaping, is mainly intended for the manufacturing of mirrors for optical systems with an angular resolution of a few arcminutes, intended to operate in extreme environments. Its principal mechanical features are very low weight and high rigidity of the resulting segments, and its cost and production time turn out to be very competitive as well. The process is based on the shaping of thin glass foils by means of forced bending at room temperature; a sandwich structure is then assembled for retaining the imposed shape. These mirrors are composted of commercial, off-the-shelf materials. In this contribution we give an overview of the latest results achieved in the manufacturing of the pre-production series of mirrors for the Medium Size and Small Size Telescopes of the Cherenkov Telescope Array observatory.

  20. The ASTRI SST-2M prototype for the Cherenkov Telescope Array: opto-mechanical test results

    NASA Astrophysics Data System (ADS)

    Canestrari, Rodolfo; Giro, Enrico; Antolini, Elisa; Bonnoli, Giacomo; Cascone, Enrico; La Palombara, Nicola; Leto, Giuseppe; Pareschi, Giovanni; Scuderi, Salvo; Stringhetti, Luca; Tanci, Claudio; Tosti, Gino

    2015-09-01

    The Cherenkov Telescope Array (CTA) observatory, with a combination of large-, medium-, and small-size telescopes (LST, MST and SST, respectively), will represent the next generation of imaging atmospheric Cherenkov telescopes. It will explore the very high-energy domain from a few tens of GeV up to few hundreds of TeV with unprecedented sensitivity, angular resolution and imaging resolution. In this framework, the Italian ASTRI program, led by the Italian National Institute of Astrophysics (INAF), is currently developing a scientific and technological SST dual-mirror end-to-end prototype named ASTRI SST-2M. It is a 4-meter class telescope; it adopts an aplanatic, wide-field, double-reflection optical layout in a Schwarzschild-Couder configuration. The ASTRI SST-2M telescope structure and mirrors have been already installed at the INAF observing station at Serra La Nave, on Mt. Etna (Sicily, Italy). In this contribution we report about the on-site deployment and the latest results on the opto-mechanical performance test conducted soon after the telescope installation

  1. Simulated gamma-ray pulse profile of the Crab pulsar with the Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    Burtovoi, A.; Zampieri, L.

    2016-07-01

    We present simulations of the very high energy (VHE) gamma-ray light curve of the Crab pulsar as observed by the Cherenkov Telescope Array (CTA). The CTA pulse profile of the Crab pulsar is simulated with the specific goal of determining the accuracy of the position of the interpulse. We fit the pulse shape obtained by the Major Atmospheric Gamma-Ray Imaging Cherenkov (MAGIC) telescope with a three-Gaussian template and rescale it to account for the different CTA instrumental and observational configurations. Simulations are performed for different configurations of CTA and for the ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) mini-array. The northern CTA configuration will provide an improvement of a factor of ˜3 in accuracy with an observing time comparable to that of MAGIC (73 h). Unless the VHE spectrum above 1 TeV behaves differently from what we presently know, unreasonably long observing times are required for a significant detection of the pulsations of the Crab pulsar with the high-energy-range sub-arrays. We also found that an independent VHE timing analysis is feasible with Large Size Telescopes. CTA will provide a significant improvement in determining the VHE pulse shape parameters necessary to constrain theoretical models of the gamma-ray emission of the Crab pulsar. One of such parameters is the shift in phase between peaks in the pulse profile at VHE and in other energy bands that, if detected, may point to different locations of the emission regions.

  2. On the use of Cherenkov Telescopes for outer Solar system body occultations

    NASA Astrophysics Data System (ADS)

    Lacki, Brian C.

    2014-12-01

    Imaging Atmospheric Cherenkov Telescopes (IACTs) are arrays of very large optical telescopes that are well-suited for rapid photometry of bright sources. I investigate their potential in observing stellar occultations by small objects in the outer Solar system, Transjovian Objects (TJOs). These occultations cast diffraction patterns on the Earth. Current IACT arrays are capable of detecting objects smaller than 100 m in radius in the Kuiper Belt and 1 km radius out to 5000 au. The future Cherenkov Telescope Array (CTA) will have even greater capabilities. Because the arrays include several telescopes, they can potentially measure the speeds of TJOs without degeneracies, and the sizes of the TJOs and background stars. I estimate the achievable precision using a Fisher matrix analysis. With CTA, the precisions of these parameter estimations will be as good as a few per cent. I consider how often detectable occultations occur by members of different TJO populations, including Centaurs, Kuiper Belt Objects (KBOs), Oort Cloud objects, and satellites and Trojans of Uranus and Neptune. The great sensitivity of IACT arrays means that they likely detect KBO occultations once every O(10) hours when looking near the ecliptic. IACTs can also set useful limits on many other TJO populations.

  3. A New Event Reconstruction Algorithm for Super-Kamiokande Water Cherenkov Detector

    NASA Astrophysics Data System (ADS)

    Tobayama, Shimpei

    2012-10-01

    Super-Kamiokande is the world's largest water Cherenkov particle detector located underground in Kamioka-mine, Gifu, Japan. The detector has been used for proton decay search, and observation of atmospheric, solar and supernova neutrinos. It also serves as the far detector for T2K long baseline neutrino oscillation experiment. The detector consists of a cylindrical tank filled with 50kt of ultra-pure water, and an array of 11,000 photomultiplier tubes (PMT) installed on the tank's inner wall record the time and intensity of the Cherenkov light emitted by charged particles traveling in the water. Using the information from the PMTs, particle type, interaction vertex, direction and momentum can be reconstructed. A new reconstruction algorithm is being developed which performs a simultaneous maximum likelihood determination of such parameters. Through Monte Carlo studies, it was found that the new algorithm has a significantly better particle identification performance and vertex/momentum resolutions, compared to the existing reconstruction software. In this talk, an outline of the new algorithm, its performance and implications on physics analyses will be presented.

  4. From MAGIC to CTA: the INAF participation to Cherenkov Telescopes experiments for very high energy astrophysics .

    NASA Astrophysics Data System (ADS)

    Antonelli, L. A.; INAF MAGIC Collaboration

    The next decade can be considered the "golden age" of the Gamma Ray Astronomy with the two satellites for Gamma Ray Astronomy (AGILE and GLAST) in orbit. Therefore, thanks to many other X-ray experiments already in orbit (e.g. Swift, Chandra, NewtonXMM, etc.) it will be possible to image the Universe for the first time all over the electromagnetic spectrum almost contemporarily. The new generations of ground-based very high gamma-ray instruments are ready to extend the observed band also to the very high frequencies. Scientists from the Italian National Institute for Astrophysics (INAF) are involved in many, both space- and ground- based gamma ray experiments, and recently such an involvement has been largely improved in the field of the Imaging Atmospheric Cherenkov Telescopes (IACT). INAF is now member of the MAGIC collaboration and is participating to the realization of the second MAGIC telescope. MAGIC, as well other IACT experiments, is not operated as an observatory so a proper guest observer program does not exist. A consortium of European scientists (including INAF scientists) is thus now thinking to the design of a new research infrastructure: the Cherenkov Telescope Array (CTA). CTA is conceived to provide 10 times the sensitivity of current instruments, combined with increased flexibility and increased coverage from some 10 GeV to some 100 TeV. CTA will be operated as an observatory to serve a wider community of astronomer and astroparticle physicists.

  5. Microsecond Time Resolution Optical Photometry using a H.E.S.S. Cherenkov Telescope

    SciTech Connect

    Deil, Christoph; Domainko, Wilfried; Hermann, German

    2008-02-22

    We have constructed an optical photometer with microsecond time resolution, which is currently being operated on one of the H.E.S.S. telescopes. H.E.S.S. is an array of four Cherenkov telescopes, each with a 107 m{sup 2} mirror, located in the Khomas highland in Namibia. In its normal mode of operation H.E.S.S. observes Cherenkov light from air showers generated by very high energy gamma-rays in the upper atmosphere. Our detector consists of seven photomultipliers, one in the center to record the lightcurve from the target and six concentric photomultipliers as a veto system to reject disturbing signals e.g. from meteorites or lightning at the horizon. The data acquisition system has been designed to continuously record the signals with zero deadtime. The Crab pulsar has been observed to verify the performance of the instrument and the GPS timing system. Compact galactic targets were observed to search for flares on timescales of a few microseconds to {approx}100 ms. The design and sensitivity of the instrument as well as the data analysis method are presented.

  6. VERITAS Distant Laser Calibration and Atmospheric Monitoring

    SciTech Connect

    Hui, C. M.

    2008-12-24

    As a calibrated laser pulse propagates through the atmosphere, the intensity of the Rayleigh scattered light arriving at the VERITAS telescopes can be calculated precisely. This allows for absolute calibration of imaging atmospheric Cherenkov telescopes (IACT) to be simple and straightforward. In these proceedings, we present the comparison between laser data and simulation to estimate the light collection efficiencies of the VERITAS telescopes, and the analysis of multiple laser data sets taken in different months for atmospheric monitoring purpose.

  7. Cherenkov Radiation from Jets in Heavy-ion Collisions

    SciTech Connect

    Koch, Volker; Majumder, Abhijit; Wang, Xin-Nian

    2005-07-26

    The possibility of Cherenkov-like gluon bremsstrahlung in dense matter is studied. We point out that the occurrence of Cherenkov radiation in dense matter is sensitive to the presence of partonic bound states. This is illustrated by a calculation of the dispersion relation of a massless particle in a simple model in which it couples to two different massive resonance states. We further argue that detailed spectroscopy of jet correlations can directly probe the index of refraction of this matter, which in turn will provide information about the mass scale of these partonic bound states.

  8. Fast timing and trigger Cherenkov detector for collider experiments

    NASA Astrophysics Data System (ADS)

    Grigoryev, V. A.; Kaplin, V. A.; Karavicheva, T. L.; Konevskikh, A. S.; Kurepin, A. B.; Loginov, V. A.; Melikyan, Yu A.; Morozov, I. V.; Reshetin, A. I.; Serebryakov, D. V.; Shabanov, A. I.; Slupecki, M.; Trzaska, W. H.; Tykmanov, E. M.

    2016-02-01

    Analysis of fast timing and trigger Cherenkov detector's design for its use in collider experiments is presented. Several specific requirements are taken into account - necessity of the radiator's placement as close to the beam pipe as possible along with the requirement of gapless (solid) radiator's design. Characteristics of the Cherenkov detector's laboratory prototype obtained using a pion beam at the CERN Proton Synchrotron are also presented, showing the possibility of obtaining sufficiently high geometrical efficiency along with good enough time resolution (50 ps sigma).

  9. Light-weight spherical mirrors for Cherenkov detectors

    NASA Astrophysics Data System (ADS)

    Cisbani, E.; Colilli, S.; Crateri, R.; Cusanno, F.; Fratoni, R.; Frullani, S.; Garibaldi, F.; Giuliani, F.; Gricia, M.; Iodice, M.; Iommi, R.; Lucentini, M.; Mostarda, A.; Pierangeli, L.; Santavenere, F.; Urciuoli, G. M.; De Leo, R.; Lagamba, L.; Nappi, E.; Braem, A.; Vernin, P.

    2003-01-01

    Light-weight spherical mirrors have been appositely designed and built for the gas threshold Cherenkov detectors of the two Hall A spectrometers. The mirrors are made of a 1 mm thick aluminized plexiglass sheet, reinforced by a rigid backing consisting of a phenolic honeycomb sandwiched between two carbon fiber mats epoxy glued. The produced mirrors have a thickness equivalent to 0.55% of radiation length, and an optical slope error of about 5.5 mrad. These characteristics make these mirrors suitable for the implementation in Cherenkov threshold detectors. Ways to improve the mirror features are also discussed in view of their possible employment in RICH detectors.

  10. The ASTRI SST-2M prototype for the Cherenkov Telescope Array: prototype technologies goals and strategies for the future SST

    NASA Astrophysics Data System (ADS)

    Marchiori, Gianpietro; Busatta, Andrea; Giacomel, Stefano; Folla, Ivan; Valsecchi, Marco; Canestrari, Rodolfo; Bonnoli, Giacomo; Cascone, Enrico; Conconi, Paolo; Fiorini, Mauro; Giro, Enrico; La Palombara, Nicola; Pareschi, Giovanni; Perri, Luca; Rodeghiero, Gabriele; Sironi, Giorgia; Stringhetti, Luca; Toso, Giorgio; Tosti, Gino; Pellicciari, Carlo

    2014-07-01

    The Cherenkov Telescope Array (CTA) observatory will represent the next generation of Imaging Atmospheric Cherenkov Telescope. Using a combination of large-, medium-, and small-scale telescopes (LST, MST, SST, respectively), it will explore the Very High Energy domain from a few tens of GeVup to about few hundreds of TeV with unprecedented sensitivity, angular resolution and imaging quality. In this framework, the Italian ASTRI program, led by the Italian National Institute of Astrophysics (INAF) developed a 4-meter class telescope, which will adopt an aplanatic, wide-field, double-reflection optical layout in a Schwarzschild- Couder configuration. Within this program INAF assigned to the consortium between Galbiati Group and EIE Group the construction, assembly and tests activities of the prototype named ASTRI SST-2M. On the basis of the lesson learnt from the prototype, other telescopes will be produced, starting from a re-design phase, in order to optimize performances and the overall costs and production schedule for the CTA-SST telescope. This paper will firstly give an overview of the concept for the SST prototype mount structure. In this contest, the technologies adopted for the design, manufacturing and tests of the entire system will be presented. Moreover, a specific focus on the challenges of the prototype and the strategies associated with it will be provided, in order to outline the near future performance goals for this type of Cherenkov telescopes employed for Gamma ray science.

  11. Comparison of absolute intensity between EAS with gamma-families and general EAS at Mount Norikura

    NASA Technical Reports Server (NTRS)

    Nakatsuka, T.; Nishikawa, K.; Saito, T.; Sakata, M.; Dake, S.; Kawamoto, M.; Mitsumune, T.; Shima, M.; Yamamoto, Y.; Kusumose, M.

    1985-01-01

    Gamma-families with total energy greater than 10 TeV, found in the EX chamber which was cooperated with the EAS array were combined with EAS triggered by big bursts. The absolute intensity of the size spectrum of these combined EAS was compared with that of general EAS obtained by AS trigger. The EAS with sizes greater than 2x1 million were always accompanied by gamma-families with sigma E sub gamma H 10 TeV, n sub gamma, H 2 and Emin=3 TeV, although the rate of EAS accompaning such gamma-families decreases rapidly as their sizes decrease.

  12. Characterizing the radiation response of Cherenkov glass detectors with isotopic sources

    SciTech Connect

    Hayward, J P; Hobbs, C. L.; Bell, Zane W; Boatner, Lynn A; Johnson, Rose E; Ramey, Joanne Oxendine; Jellison Jr, Gerald Earle; Lillard, Cole R; Ramey, Lucas A

    2012-01-01

    Abstract Cherenkov detectors are widely used for particle identification and threshold detectors in high-energy physics. Glass Cherenkov detectors that are sensitive to beta emissions originating from neutron activation have been demonstrated recently as a potential replacement for activation foils. In this work, we set the groundwork to evaluate large Cherenkov glass detectors for sensitivity to MeV photons through first understanding the measured response of small Cherenkov glass detectors to isotopic gamma-ray sources. Counting and pulse height measurements are acquired with reflected glass Cherenkov detectors read out with a photomultiplier tube. Simulation was used to inform our understanding of the measured results. This simulation included radioactive source decay, radiation interaction, Cherenkov light generation, optical ray tracing, and photoelectron production. Implications for the use of Cherenkov glass detectors to measure low energy gammaray response are discussed.

  13. The operation of a pressurized ultraviolet photoionization threshold cherenkov counter

    NASA Astrophysics Data System (ADS)

    Harnew, N.; Meyer, D. I.

    We have successfully tested an ultraviolet photoionization Cherenkov counter in a 10 GeV/ c pion beam. The counter has been tested to 11 atm pressure for use as a π-K separator. The design and operation of the counter is described.

  14. The C 4F 10 Cherenkov detector for DIRAC-II

    NASA Astrophysics Data System (ADS)

    Horikawa, S.; Allkofer, Y.; Amsler, C.; Brekhovskikh, V.; Kuptsov, A.; Pentia, M.; Zhabitsky, M.

    2008-09-01

    A new threshold Cherenkov detector using C 4F 10 gas radiator was built and put into operation in the DIRAC-II experiment at CERN. Running on the C 4F 10 at room temperature and atmospheric pressure, the detector discriminates between pions and kaons in the momentum range of 4- 8 GeV/c. A compact radiator-gas recirculation system including a gas-liquid separation unit, hollow-fibre membranes and molecular sieves ensures gas purity for a long term of operation without a significant loss of the gas. The system is robust and stable and the pressure in the two detector vessels is regulated in the range of ±0.5 mbar. We report on the design and the technical aspects of the detector and its response in the DIRAC 2007 run.

  15. A hybrid version of the Whipple observatory's air Cherenkov imaging camera for use in moonlight

    NASA Astrophysics Data System (ADS)

    Chantell, M. C.; Akerlof, C. W.; Badran, H. M.; Buckley, J.; Carter-Lewis, D. A.; Cawley, M. F.; Connaughton, V.; Fegan, D. J.; Fleury, P.; Gaidos, J.; Hillas, A. M.; Lamb, R. C.; Pare, E.; Rose, H. J.; Rovero, A. C.; Sarazin, X.; Sembroski, G.; Schubnell, M. S.; Urban, M.; Weekes, T. C.; Wilson, C.

    1997-02-01

    A hybrid version of the Whipple Observatory's atmospheric Cherenkov imaging camera that permits observation during periods of bright moonlight is described. The hybrid camera combines a blue-light blocking filter with the standard Whipple imaging camera to reduce sensitivity to wavelengths greater than 360 nm. Data taken with this camera are found to be free from the effects of the moonlit night-sky after the application of simple off-line noise filtering. This camera has been used to successfully detect TeV gamma rays, in bright moon light, from both the Crab Nebula and the active galactic nucleus Markarian 421 at the 4.9σ and 3.9σ levels of statistical significance, respectively. The energy threshold of the camera is estimated to be 1.1 ( +0.6/-0.3) TeV from Monte Carlo simulations.

  16. EAS selection in the EMMA underground array

    NASA Astrophysics Data System (ADS)

    Sarkamo, J.; Bezrukov, L.; Enqvist, T.; Fynbo, H.; Inzhechik, L.; Joutsenvaara, J.; Kalliokoski, T.; Kuusiniemi, P.; Loo, K.; Lubsandorzhiev, B.; Monto, T.; Petkov, V.; Räihä, T.; Slupecki, M.; Trzaska, W. H.; Virkajärvi, A.

    2013-02-01

    The first measurements of the Experiment with MultiMuon Array (EMMA) have been analyzed for the selection of the Extensive Air Showers (EAS). Test data were recorded with an underground muon tracking station and a satellite station separated laterally by 10 metres. Events with tracks distributed over all of the tracking detector area and even extending over to the satellite station are identified as EAS. The recorded multiplicity spectrum of the events is in general agreement with CORSIKA EAS simulation and demonstrates the array's capability of EAS detection.

  17. Radium-228 analysis of natural waters by Cherenkov counting of Actinium-228.

    PubMed

    Aleissa, Khalid A; Almasoud, Fahad I; Islam, Mohammed S; L'Annunziata, Michael F

    2008-12-01

    The activities of (228)Ra in natural waters were determined by the Cherenkov counting of the daughter nuclide (228)Ac. The radium was pre-concentrated on MnO(2) and the radium purified via ion exchange and, after a 2-day period of incubation to allow for secular equilibrium between the parent-daughter (228)Ra((228)Ac), the daughter nuclide (228)Ac was isolated by ion exchange according to the method of Nour et al. [2004. Radium-228 determination of natural waters via concentration on manganese dioxide and separation using Diphonix ion exchange resin. Appl. Radiat. Isot. 61, 1173-1178]. The Cherenkov photons produced by (228)Ac were counted directly without the addition of any scintillation reagents. The optimum Cherenkov counting window, sample volume, and vial type were determined experimentally to achieve optimum Cherenkov photon detection efficiency and lowest background count rates. An optimum detection efficiency of 10.9+/-0.1% was measured for (228)Ac by Cherenkov counting with a very low Cherenkov photon background of 0.317+/-0.013cpm. The addition of sodium salicylate into the sample counting vial at a concentration of 0.1g/mL yielded a more than 3-fold increase in the Cherenkov detection efficiency of (228)Ac to 38%. Tests of the Cherenkov counting technique were conducted with several water standards of known activity and the results obtained compared closely with a conventional liquid scintillation counting technique. The advantages and disadvantages of Cherenkov counting compared to liquid scintillation counting methods are discussed. Advantages include much lower Cherenkov background count rates and consequently lower minimal detectable activities for (228)Ra and no need for expensive environmentally unfriendly liquid scintillation cocktails. The disadvantages of the Cherenkov counting method include the need to measure (228)Ac Cherenkov photon detection efficiency and optimum Cherenkov counting volume, which are not at all required when liquid

  18. EVALUATION OF HFC 245CA AND HFC 236EA AS FOAM BLOWING AGENTS

    EPA Science Inventory

    The paper gives results of a limited evaluation of the developmental hydrofluorocarbons (HFCS) 245ca and 236ea as blowing agents in urethane-based insulation. hese materials were selected from screening tests of 37 C2, C3, and C4 isomers based on physical properties, atmospheric ...

  19. 47 CFR 11.18 - EAS Designations.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... source of EAS Local Area messages. An LP source is responsible for coordinating the carriage of common... as specified in its EAS Local Area Plan. If it is unable to carry out this function, other LP sources in the Local Area may be assigned the responsibility as indicated in State and Local Area Plans....

  20. 47 CFR 11.18 - EAS Designations.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... source of EAS Local Area messages. An LP source is responsible for coordinating the carriage of common... as specified in its EAS Local Area Plan. If it is unable to carry out this function, other LP sources in the Local Area may be assigned the responsibility as indicated in State and Local Area Plans....

  1. 32 CFR 651.34 - EA components.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) ENVIRONMENTAL QUALITY ENVIRONMENTAL ANALYSIS OF ARMY ACTIONS (AR 200-2) Environmental Assessment § 651.34 EA components. EAs should be... affected environment and establish the environmental setting against which environmental effects...

  2. 32 CFR 651.34 - EA components.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) ENVIRONMENTAL QUALITY ENVIRONMENTAL ANALYSIS OF ARMY ACTIONS (AR 200-2) Environmental Assessment § 651.34 EA components. EAs should be... affected environment and establish the environmental setting against which environmental effects...

  3. 32 CFR 651.34 - EA components.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) ENVIRONMENTAL QUALITY ENVIRONMENTAL ANALYSIS OF ARMY ACTIONS (AR 200-2) Environmental Assessment § 651.34 EA components. EAs should be... affected environment and establish the environmental setting against which environmental effects...

  4. 32 CFR 651.34 - EA components.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) ENVIRONMENTAL QUALITY ENVIRONMENTAL ANALYSIS OF ARMY ACTIONS (AR 200-2) Environmental Assessment § 651.34 EA components. EAs should be... affected environment and establish the environmental setting against which environmental effects...

  5. 32 CFR 651.34 - EA components.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) ENVIRONMENTAL QUALITY ENVIRONMENTAL ANALYSIS OF ARMY ACTIONS (AR 200-2) Environmental Assessment § 651.34 EA components. EAs should be... affected environment and establish the environmental setting against which environmental effects...

  6. Study of a Cherenkov TOF-PET module

    NASA Astrophysics Data System (ADS)

    Korpar, S.; Dolenec, R.; Križan, P.; Pestotnik, R.; Stanovnik, A.

    2013-12-01

    An apparatus, consisting of two PbF2 crystals, each coupled to a multichannel plate photomultiplier (MCP-PMT), has been constructed in order to measure the time-of-flight (TOF) of the two 511 keV annihilation photons produced in positron emission tomography (PET). Excellent timing is achieved by detecting the prompt Cherenkov photons produced by the absorption of the 511 keV gamma photons. The present work describes the measurement and image reconstruction of two 22Na point sources. In addition, the influence of the radiator thickness and the Cherenkov light absorption cut-off of the crystal on the efficiency and the timing resolution have been studied by Monte Carlo simulation.

  7. Data analysis for solar neutrinos observed by water Cherenkov detectors⋆

    NASA Astrophysics Data System (ADS)

    Koshio, Yusuke

    2016-04-01

    A method of analyzing solar neutrino measurements using water-based Cherenkov detectors is presented. The basic detection principle is that the Cherenkov photons produced by charged particles via neutrino interaction are observed by photomultiplier tubes. A large amount of light or heavy water is used as a medium. The first detector to successfully measure solar neutrinos was Kamiokande in the 1980's. The next-generation detectors, i.e., Super-Kamiokande and the Sudbury Neutrino Observatory (SNO), commenced operation from the mid-1990's. These detectors have been playing the critical role of solving the solar neutrino problem and determining the neutrino oscillation parameters over the last decades. The future prospects of solar neutrino analysis using this technique are also described.

  8. Nonlinear saturation characteristics of a dielectric Cherenkov maser

    SciTech Connect

    Choi, J.S.; Heo, E.G.; Choi, D.I.

    1995-12-31

    The nonlinear saturation state in a dielectric Cherenkov maser (DCM) with the TM mode and the intense relativistic electron beam is analyzed from the nonlinear formulation based on the cold fluid-Maxwell equations. We obtain the nonlinear efficiency and the final operation frequency under consideration of the effects of the beam current, the beam energy and the dielectric materials and show that the characteristics of a DCM instablity has a strong resemblance to that of the relativistic two stream instability by the coherent trapping of electrons in a single most-ustable wave. Finally, the nonlinear analysis shows that the Cherenkov maser operation with a lower-energy beam can be more efficient in the higher frequency regime for the case of the high power DCM with a high current.

  9. A ring imaging Cherenkov detector for CLAS12

    SciTech Connect

    Montgomery, Rachel A.

    2013-12-01

    The energy increase of Jefferson Lab's Continuous Electron Beam Accelerator Facility (CEBAF) to 12 GeV promises to greatly extend the physics reach of its experiments. This will include an upgrade of the CEBAF Large Acceptance Spectrometer (CLAS) to CLAS12, offering unique possibilities to study internal nucleon dynamics. For this excellent hadron identification over the full kinematical range of 3–8 GeV/c is essential. This will be achieved by the installation of a Ring Imaging CHerenkov (RICH) detector. A novel hybrid imaging design incorporating mirrors, aerogel radiators and Hamamatsu H8500 multianode photomultiplier tubes is proposed. Depending on the incident particle track angle, Cherenkov light will either be imaged directly or after two reflections and passes through the aerogel. The detector design is described, along with preliminary results on individual detector components tests and from recent testbeam studies.

  10. GEANT4 simulations of Cherenkov reaction history diagnostics.

    PubMed

    Rubery, M S; Horsfield, C J; Herrmann, H W; Kim, Y; Mack, J M; Young, C S; Caldwell, S E; Evans, S C; Sedilleo, T J; McEvoy, A; Miller, E K; Stoeffl, W; Ali, Z; Toebbe, J

    2010-10-01

    This paper compares the results from a GEANT4 simulation of the gas Cherenkov detector 1 (GCD1) with previous simulations and experimental data from the Omega laser facility. The GCD1 collects gammas emitted during a deuterium-tritium capsule implosion and converts them, through several processes, to Cherenkov light. Photon signals are recorded using subnanosecond photomultiplier tubes, producing burn reaction histories. The GEANT4 GCD1 simulation is first benchmarked against ACCEPT, an integrated tiger series code, with good agreement. The simulation is subsequently compared with data from the Omega laser facility, where experiments have been performed to measure the effects of Hohlraum materials on reaction history signals, in preparation for experiments at the National Ignition Facility. PMID:21033850

  11. GEANT4 simulations of Cherenkov reaction history diagnostics

    SciTech Connect

    Rubery, M. S.; Horsfield, C. J.; Herrmann, H. W.; Kim, Y.; Mack, J. M.; Young, C. S.; Caldwell, S. E.; Evans, S. C.; Sedilleo, T. J.; McEvoy, A.; Miller, E. K.; Stoeffl, W.; Ali, Z.

    2010-10-15

    This paper compares the results from a GEANT4 simulation of the gas Cherenkov detector 1 (GCD1) with previous simulations and experimental data from the Omega laser facility. The GCD1 collects gammas emitted during a deuterium-tritium capsule implosion and converts them, through several processes, to Cherenkov light. Photon signals are recorded using subnanosecond photomultiplier tubes, producing burn reaction histories. The GEANT4 GCD1 simulation is first benchmarked against ACCEPT, an integrated tiger series code, with good agreement. The simulation is subsequently compared with data from the Omega laser facility, where experiments have been performed to measure the effects of Hohlraum materials on reaction history signals, in preparation for experiments at the National Ignition Facility.

  12. Optical Cherenkov radiation in ultrafast cascaded second-harmonic generation

    NASA Astrophysics Data System (ADS)

    Bache, M.; Bang, O.; Zhou, B. B.; Moses, J.; Wise, F. W.

    2010-12-01

    We show through theory and numerics that when few-cycle femtosecond solitons are generated through cascaded (phase-mismatched) second-harmonic generation, these broadband solitons can emit optical Cherenkov radiation in the form of linear dispersive waves located in the red part of the spectrum. The beating between the dispersive wave and the soliton generates trailing temporal oscillations on the compressed soliton. Insertion of a simple short-wave pass filter after the crystal can restore a clean soliton. On the other hand, bandpass filtering around the dispersive wave peak results in near-transform-limited ultrashort mid-IR pulses with pulse durations much shorter than the input near-IR pulse. The Cherenkov radiation for the crystal considered (β-barium borate) is found for pump wavelengths in the range λ=0.95-1.45μm, and is located in the regime λ=1.5-3.5μm. For shorter pump wavelengths, the phase-matching point is located in the absorption region of the crystal, effectively absorbing the generated dispersive wave. By calculating the phase-matching curves for typically used frequency conversion crystals, we point out that the mid-IR absorption in the crystal in many cases automatically will filter away the dispersive wave. Finally, an investigation of recent experimental results uncovers a four-wave-mixing phenomenon related to Cherenkov radiation that is an additional generation mechanism of long-wavelength radiation that can occur during soliton compression. We discuss the conditions that lead to this alternative dynamics rather than generation of Cherenkov radiation.

  13. Cherenkov-type diagnostics of fast electrons within tokamak plasmas

    NASA Astrophysics Data System (ADS)

    Jakubowski, Lech; Sadowski, Marek J.; Zebrowski, Jaroslaw; Malinowski, Karol; Rabinski, Marek; Jakubowski, Marcin J.; Mirowski, Robert

    2014-05-01

    This paper presents a summary of the most important results of fast electron measurements performed so far within different tokamaks by means of Cherenkov-type detectors. In the ISTTOK tokamak (IPFN, IST, Lisboa, Portugal), two measuring heads were applied, each equipped with four radiators made of different types of alumina-nitrate poly-crystals. A two-channel measuring head equipped with diamond radiators was also used. Within the COMPASS tokamak (IPP AS CR, Prague, Czech Republic) some preliminary measurements have recently been performed by means of a new single-channel Cherenkov-type detector. The experimental data from the TORE SUPRA tokamak (CEA, IFRM, Cadarache, France), which were collected by means of a DENEPR-2 probe during two recent experimental campaigns, have been briefly analyzed. A new Cherenkov probe (the so-called DENEPR-3) has been mounted within the TORE SUPRA machine, but the electron measurements could not be performed because of the failure of this facility. Some conclusions concerning the fast electron emission are presented.

  14. Simulation of the ASTRI two-mirrors small-size telescope prototype for the Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    Bigongiari, C.; Cusumano, G.; Di Pierro, F.; La Parola, V.; Stamerra, A.; Vallania, P.; ASTRI Collaboration; CTA Consortium, the

    2016-05-01

    The Cherenkov Telescope Array (CTA) is a world-wide project to build a new generation ground-based gamma-ray instrument operating in the energy range from some tens of GeV to above 100 TeV. To ensure full sky coverage CTA will consist of two arrays of Imaging Atmospheric Cherenkov Telescopes (IACTs), one in the southern hemisphere and another one in the northern hemisphere. CTA has just completed the design phase and it is entering in the pre-production one that includes the development of telescope precursor mini-arrays. ASTRI is an ongoing project, to develop and install at the southern CTA site one of such mini-arrays composed by nine dual-mirror small size telescopes equipped with an innovative camera based on silicon photomultiplier sensors. The end-to-end telescope prototype, named ASTRI SST-2M, has been recently inaugurated at the Serra La Nave observing station, on Mount Etna, Italy. ASTRI SST-2M expected performance has been carefully studied using a full Monte Carlo simulation of the shower development in the atmosphere and detector response. Simulated data have been analyzed using the traditional Hillas moment analysis to obtain the expected angular and energy resolution. Simulation results, together with the comparison with the available experimental measurements, are shown.

  15. Simultaneous operation and control of about 100 telescopes for the Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    Wegner, P.; Colomé, J.; Hoffmann, D.; Houles, J.; Köppel, H.; Lamanna, G.; Le Flour, T.; Lopatin, A.; Lyard, E.; Melkumyan, D.; Oya, I.; Panazol, L.-I.; Punch, M.; Schlenstedt, S.; Schmidt, T.; Stegmann, C.; Schwanke, U.; Walter, R.; Consortium, CTA

    2012-12-01

    The Cherenkov Telescope Array (CTA) project is an initiative to build the next generation ground-based very high energy (VHE) gamma-ray instrument. Compared to current imaging atmospheric Cherenkov telescope experiments CTA will extend the energy range and improve the angular resolution while increasing the sensitivity up to a factor of 10. With about 100 separate telescopes it will be operated as an observatory open to a wide astrophysics and particle physics community, providing a deep insight into the non-thermal high-energy universe. The CTA Array Control system (ACTL) is responsible for several essential control tasks supporting the evaluation and selection of proposals, as well as the preparation, scheduling, and finally the execution of observations with the array. A possible basic distributed software framework for ACTL being considered is the ALMA Common Software (ACS). The ACS framework follows a container component model and contains a high level abstraction layer to integrate different types of device. To achieve a low-level consolidation of connecting control hardware, OPC UA (OPen Connectivity-Unified Architecture) client functionality is integrated directly into ACS, thus allowing interaction with other OPC UA capable hardware. The CTA Data Acquisition System comprises the data readout of all cameras and the transfer of the data to a camera server farm, thereby using standard hardware and software technologies. CTA array control is also covering conceptions for a possible array trigger system and the corresponding clock distribution. The design of the CTA observations scheduler is introducing new algorithmic technologies to achieve the required flexibility.

  16. Monte Carlo studies of medium-size telescope designs for the Cherenkov Telescope Array

    SciTech Connect

    Wood, M. D.; Jogler, T.; Dumm, J.; Funk, S.

    2015-06-07

    In this paper, we present studies for optimizing the next generation of ground-based imaging atmospheric Cherenkov telescopes (IACTs). Results focus on mid-sized telescopes (MSTs) for CTA, detecting very high energy gamma rays in the energy range from a few hundred GeV to a few tens of TeV. We describe a novel, flexible detector Monte Carlo package, FAST (FAst Simulation for imaging air cherenkov Telescopes), that we use to simulate different array and telescope designs. The simulation is somewhat simplified to allow for efficient exploration over a large telescope design parameter space. We investigate a wide range of telescope performance parameters including optical resolution, camera pixel size, and light collection area. In order to ensure a comparison of the arrays at their maximum sensitivity, we analyze the simulations with the most sensitive techniques used in the field, such as maximum likelihood template reconstruction and boosted decision trees for background rejection. Choosing telescope design parameters representative of the proposed Davies–Cotton (DC) and Schwarzchild–Couder (SC) MST designs, we compare the performance of the arrays by examining the gamma-ray angular resolution and differential point-source sensitivity. We further investigate the array performance under a wide range of conditions, determining the impact of the number of telescopes, telescope separation, night sky background, and geomagnetic field. We find a 30–40% improvement in the gamma-ray angular resolution at all energies when comparing arrays with an equal number of SC and DC telescopes, significantly enhancing point-source sensitivity in the MST energy range. Finally, we attribute the increase in point-source sensitivity to the improved optical point-spread function and smaller pixel size of the SC telescope design.

  17. Monte Carlo studies of medium-size telescope designs for the Cherenkov Telescope Array

    DOE PAGESBeta

    Wood, M. D.; Jogler, T.; Dumm, J.; Funk, S.

    2015-06-07

    In this paper, we present studies for optimizing the next generation of ground-based imaging atmospheric Cherenkov telescopes (IACTs). Results focus on mid-sized telescopes (MSTs) for CTA, detecting very high energy gamma rays in the energy range from a few hundred GeV to a few tens of TeV. We describe a novel, flexible detector Monte Carlo package, FAST (FAst Simulation for imaging air cherenkov Telescopes), that we use to simulate different array and telescope designs. The simulation is somewhat simplified to allow for efficient exploration over a large telescope design parameter space. We investigate a wide range of telescope performance parametersmore » including optical resolution, camera pixel size, and light collection area. In order to ensure a comparison of the arrays at their maximum sensitivity, we analyze the simulations with the most sensitive techniques used in the field, such as maximum likelihood template reconstruction and boosted decision trees for background rejection. Choosing telescope design parameters representative of the proposed Davies–Cotton (DC) and Schwarzchild–Couder (SC) MST designs, we compare the performance of the arrays by examining the gamma-ray angular resolution and differential point-source sensitivity. We further investigate the array performance under a wide range of conditions, determining the impact of the number of telescopes, telescope separation, night sky background, and geomagnetic field. We find a 30–40% improvement in the gamma-ray angular resolution at all energies when comparing arrays with an equal number of SC and DC telescopes, significantly enhancing point-source sensitivity in the MST energy range. Finally, we attribute the increase in point-source sensitivity to the improved optical point-spread function and smaller pixel size of the SC telescope design.« less

  18. Monte Carlo studies of medium-size telescope designs for the Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    Wood, M.; Jogler, T.; Dumm, J.; Funk, S.

    2016-01-01

    We present studies for optimizing the next generation of ground-based imaging atmospheric Cherenkov telescopes (IACTs). Results focus on mid-sized telescopes (MSTs) for CTA, detecting very high energy gamma rays in the energy range from a few hundred GeV to a few tens of TeV. We describe a novel, flexible detector Monte Carlo package, FAST (FAst Simulation for imaging air cherenkov Telescopes), that we use to simulate different array and telescope designs. The simulation is somewhat simplified to allow for efficient exploration over a large telescope design parameter space. We investigate a wide range of telescope performance parameters including optical resolution, camera pixel size, and light collection area. In order to ensure a comparison of the arrays at their maximum sensitivity, we analyze the simulations with the most sensitive techniques used in the field, such as maximum likelihood template reconstruction and boosted decision trees for background rejection. Choosing telescope design parameters representative of the proposed Davies-Cotton (DC) and Schwarzchild-Couder (SC) MST designs, we compare the performance of the arrays by examining the gamma-ray angular resolution and differential point-source sensitivity. We further investigate the array performance under a wide range of conditions, determining the impact of the number of telescopes, telescope separation, night sky background, and geomagnetic field. We find a 30-40% improvement in the gamma-ray angular resolution at all energies when comparing arrays with an equal number of SC and DC telescopes, significantly enhancing point-source sensitivity in the MST energy range. We attribute the increase in point-source sensitivity to the improved optical point-spread function and smaller pixel size of the SC telescope design.

  19. Stellar intensity interferometry over kilometer baselines: laboratory simulation of observations with the Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    Dravins, Dainis; Lagadec, Tiphaine

    2014-07-01

    A long-held astronomical vision is to realize diffraction-limited optical aperture synthesis over kilometer baselines. This will enable imaging of stellar surfaces and their environments, show their evolution over time, and reveal interactions of stellar winds and gas flows in binary star systems. An opportunity is now opening up with the large telescope arrays primarily erected for measuring Cherenkov light in air induced by gamma rays. With suitable software, such telescopes could be electronically connected and used also for intensity interferometry. With no optical connection between the telescopes, the error budget is set by the electronic time resolution of a few nanoseconds. Corresponding light-travel distances are on the order of one meter, making the method practically insensitive to atmospheric turbulence or optical imperfections, permitting both very long baselines and observing at short optical wavelengths. Theoretical modeling has shown how stellar surface images can be retrieved from such observations and here we report on experimental simulations. In an optical laboratory, artificial stars (single and double, round and elliptic) are observed by an array of telescopes. Using high-speed photon-counting solid-state detectors and real-time electronics, intensity fluctuations are cross correlated between up to a hundred baselines between pairs of telescopes, producing maps of the second-order spatial coherence across the interferometric Fourier-transform plane. These experiments serve to verify the concepts and to optimize the instrumentation and observing procedures for future observations with (in particular) CTA, the Cherenkov Telescope Array, aiming at order-of-magnitude improvements of the angular resolution in optical astronomy.

  20. Searching for Dark Matter signatures in dwarf spheroidal galaxies with the ASTRI mini-array in the framework of Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    Giammaria, P.; Lombardi, S.; Antonelli, L. A.; Brocato, E.; Bigongiari, C.; Di Pierro, F.; Stamerra, A.; ASTRI Collaboration; CTA Consortium, the

    2016-07-01

    The nature of Dark Matter (DM) is an open issue of modern physics. Cosmological considerations and observational evidences indicate a behaviour beyond the Standard Model for feasible DM particle candidates. Non-baryonic DM is compatible with cold and weakly interacting massive particles (WIMPs) expected to have a mass in the range between ∼10 GeV and ∼100 TeV. Indirect DM searches with imaging atmospheric Cherenkov telescopes may play a crucial role in constraining the nature of the DM particle(s) through the study of their annihilation in very high energy (VHE) gamma rays from promising targets, such as the dwarf spheroidal satellite galaxies (dSphs) of the Milky Way. Here, we focus on indirect DM searches in dSphs, presenting the preliminary prospects of this research beyond the TeV mass region achievable with the ASTRI mini-array, proposed to be installed at the Cherenkov Telescope Array southern site.

  1. Applications of Cherenkov Light Emission for Dosimetry in Radiation Therapy

    NASA Astrophysics Data System (ADS)

    Glaser, Adam Kenneth

    Since its discovery in the 1930's, the Cherenkov effect has been paramount in the development of high-energy physics research. It results in light emission from charged particles traveling faster than the local speed of light in a dielectric medium. The ability of this emitted light to describe a charged particle's trajectory, energy, velocity, and mass has allowed scientists to study subatomic particles, detect neutrinos, and explore the properties of interstellar matter. However, only recently has the phenomenon been considered in the practical context of medical physics and radiation therapy dosimetry, where Cherenkov light is induced by clinical x-ray photon, electron, and proton beams. To investigate the relationship between this phenomenon and dose deposition, a Monte Carlo plug-in was developed within the Geant4 architecture for medically-oriented simulations (GAMOS) to simulate radiation-induced optical emission in biological media. Using this simulation framework, it was determined that Cherenkov light emission may be well suited for radiation dosimetry of clinically used x-ray photon beams. To advance this application, several novel techniques were implemented to realize the maximum potential of the signal, such as time-gating for maximizing the signal to noise ratio (SNR) and Cherenkov-excited fluorescence for generating isotropic light release in water. Proof of concept experiments were conducted in water tanks to demonstrate the feasibility of the proposed method for two-dimensional (2D) projection imaging, three-dimensional (3D) parallel beam tomography, large field of view 3D cone beam tomography, and video-rate dynamic imaging of treatment plans for a number of common radiotherapy applications. The proposed dosimetry method was found to have a number of unique advantages, including but not limited to its non-invasive nature, water-equivalence, speed, high-resolution, ability to provide full 3D data, and potential to yield data in-vivo. Based on

  2. Tskhra-Tskaro complex intended for the investigations of EAS spatial characteristics near axis

    NASA Technical Reports Server (NTRS)

    Verbetski, Y. G.; Kotlyarevski, D. M.; Novalov, A. A.; Paziashvili, I. V.; Rusishvili, N. S.; Berdzenishvili, O. L.; Gromov, Y. A.; Khachaturyan, L. S.; Tsomaya, P. V.; Sharvadze, Z. S.

    1985-01-01

    Tskhra-Tskaro EAS complex located at the height of 2500 m above sea level is intended for a correlated investigation of three main components of the extended atmospheric showers (EAS) - hadron, muon and electro-proton ones - near the shower axis. This complex is aimed at the investigation of proton and primary cosmic radiation nucleus interactions with the nuclei of air atoms within the energy range 10 to the 14th power to 10 to the 16th power eV. Research equipment design and installation are discussed.

  3. 47 CFR 11.61 - Tests of EAS procedures.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Tests of EAS procedures. 11.61 Section 11.61 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Tests § 11.61 Tests of EAS procedures. (a) EAS Participants shall conduct tests at regular intervals, as specified in paragraphs (a)(1) and (a)(2) of this...

  4. 75 FR 45110 - EasTrans, LLC; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-08-02

    ... Energy Regulatory Commission EasTrans, LLC; Notice of Filing July 26, 2010. Take notice that on July 15, 2010, EasTrans, LLC (EasTrans) filed to significantly modify its Statement of Operating Conditions to provide clarification and reflect the implementation of a new EasTrans nomination process. Any...

  5. 14 CFR 1216.308 - Supplemental EAs and EISs.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... Supplemental EAs and EISs. As detailed in CEQ regulations, supplemental documentation may be required for previous EAs or EISs (see 40 CFR 1502.9). If changed circumstances require preparation of a supplemental EA... 14 Aeronautics and Space 5 2014-01-01 2014-01-01 false Supplemental EAs and EISs. 1216.308...

  6. 14 CFR 1216.308 - Supplemental EAs and EISs.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... Supplemental EAs and EISs. As detailed in CEQ regulations, supplemental documentation may be required for previous EAs or EISs (see 40 CFR 1502.9). If changed circumstances require preparation of a supplemental EA... 14 Aeronautics and Space 5 2013-01-01 2013-01-01 false Supplemental EAs and EISs. 1216.308...

  7. 7 CFR 1794.71 - Adoption of an EA.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 12 2010-01-01 2010-01-01 false Adoption of an EA. 1794.71 Section 1794.71... AGRICULTURE (CONTINUED) ENVIRONMENTAL POLICIES AND PROCEDURES Adoption of Environmental Documents § 1794.71 Adoption of an EA. RUS may adopt a Federal EA or EIS or a portion thereof as its EA. RUS shall make the...

  8. 7 CFR 1794.71 - Adoption of an EA.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 7 Agriculture 12 2012-01-01 2012-01-01 false Adoption of an EA. 1794.71 Section 1794.71... AGRICULTURE (CONTINUED) ENVIRONMENTAL POLICIES AND PROCEDURES Adoption of Environmental Documents § 1794.71 Adoption of an EA. RUS may adopt a Federal EA or EIS or a portion thereof as its EA. RUS shall make the...

  9. 7 CFR 1794.71 - Adoption of an EA.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 7 Agriculture 12 2011-01-01 2011-01-01 false Adoption of an EA. 1794.71 Section 1794.71... AGRICULTURE (CONTINUED) ENVIRONMENTAL POLICIES AND PROCEDURES Adoption of Environmental Documents § 1794.71 Adoption of an EA. RUS may adopt a Federal EA or EIS or a portion thereof as its EA. RUS shall make the...

  10. 7 CFR 1794.71 - Adoption of an EA.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

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  11. 47 CFR 11.41 - Participation in EAS.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Participation in EAS. 11.41 Section 11.41 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Organization § 11.41 Participation in EAS. (a) All EAS Participants specified in § 11.11 are categorized as Participating...

  12. 47 CFR 11.44 - EAS message priorities.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false EAS message priorities. 11.44 Section 11.44 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Organization § 11.44 EAS message priorities. (a) A national activation of the EAS for a Presidential message with the Event...

  13. 47 CFR 11.11 - The Emergency Alert System (EAS).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false The Emergency Alert System (EAS). 11.11 Section 11.11 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) General § 11.11 The Emergency Alert System (EAS). (a) The EAS is composed of analog radio broadcast stations including AM, FM, and Low-power FM...

  14. 47 CFR 11.11 - The Emergency Alert System (EAS).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false The Emergency Alert System (EAS). 11.11 Section 11.11 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) General § 11.11 The Emergency Alert System (EAS). (a) The EAS is composed of analog radio broadcast stations including AM, FM, and Low-power FM...

  15. 47 CFR 11.61 - Tests of EAS procedures.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Tests of EAS procedures. 11.61 Section 11.61 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Tests § 11.61 Tests of EAS procedures. (a) EAS Participants shall conduct tests at regular intervals, as specified in paragraphs (a)(1) and (a)(2) of this...

  16. 47 CFR 11.11 - The Emergency Alert System (EAS).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false The Emergency Alert System (EAS). 11.11 Section 11.11 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) General § 11.11 The Emergency Alert System (EAS). (a) The EAS is composed of analog radio broadcast stations including AM, FM, and Low-power FM...

  17. 47 CFR 11.61 - Tests of EAS procedures.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Tests of EAS procedures. 11.61 Section 11.61 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Tests § 11.61 Tests of EAS procedures. (a) EAS Participants shall conduct tests at regular intervals, as specified in paragraphs (a)(1) and (a)(2) of this...

  18. 47 CFR 11.61 - Tests of EAS procedures.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Tests of EAS procedures. 11.61 Section 11.61 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Tests § 11.61 Tests of EAS procedures. (a) EAS Participants shall conduct tests at regular intervals, as specified in paragraphs (a)(1) and (a)(2) of this...

  19. 47 CFR 11.15 - EAS Operating Handbook.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false EAS Operating Handbook. 11.15 Section 11.15 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) General § 11.15 EAS... at EAS Participant facilities upon receipt of an EAN, an EAT, tests, or State and Local Area...

  20. 47 CFR 11.41 - Participation in EAS.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Participation in EAS. 11.41 Section 11.41 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Organization § 11.41 Participation in EAS. (a) All EAS Participants specified in § 11.11 are categorized as Participating...

  1. 47 CFR 11.41 - Participation in EAS.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Participation in EAS. 11.41 Section 11.41 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Organization § 11.41 Participation in EAS. All EAS Participants specified in § 11.11 are categorized as Participating National...

  2. 47 CFR 11.15 - EAS Operating Handbook.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false EAS Operating Handbook. 11.15 Section 11.15 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) General § 11.15 EAS... at EAS Participant facilities upon receipt of an EAN, an EAT, tests, or State and Local Area...

  3. 47 CFR 11.44 - EAS message priorities.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false EAS message priorities. 11.44 Section 11.44 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Organization § 11.44 EAS message priorities. (a) A national activation of the EAS for a Presidential message with the Event...

  4. 47 CFR 11.41 - Participation in EAS.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Participation in EAS. 11.41 Section 11.41 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Organization § 11.41 Participation in EAS. All EAS Participants specified in § 11.11 are categorized as Participating National...

  5. 47 CFR 11.15 - EAS Operating Handbook.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false EAS Operating Handbook. 11.15 Section 11.15 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) General § 11.15 EAS... at EAS Participant facilities upon receipt of an EAN, an EAT, tests, or State and Local Area...

  6. 47 CFR 11.15 - EAS Operating Handbook.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false EAS Operating Handbook. 11.15 Section 11.15 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) General § 11.15 EAS... at EAS Participant facilities upon receipt of an EAN, an EAT, tests, or State and Local Area...

  7. 47 CFR 11.41 - Participation in EAS.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Participation in EAS. 11.41 Section 11.41 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Organization § 11.41 Participation in EAS. All EAS Participants specified in § 11.11 are categorized as Participating National...

  8. 47 CFR 11.15 - EAS Operating Handbook.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false EAS Operating Handbook. 11.15 Section 11.15 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) General § 11.15 EAS Operating Handbook. The EAS Operating Handbook states in summary form the actions to be taken by...

  9. A fast ring-imaging Cherenkov counter for a fixed-target heavy-quark experiment

    SciTech Connect

    Kaplan, D.M.; Isenhower, L.D.; Atac, M. |; Brown, C.N.; Darden, C.W.

    1993-06-01

    We present a design for a fast ring-imaging Cherenkov counter operating in the visible. The Cherenkov photons are imaged on an array of small Winston cones and read out with optical fibers and VLPCs. the design is optimized for {pi}/K/p separation in the range 10 < p < 100 GeV/c.

  10. π/K/p identification with a large-aperture ring-imaging cherenkov counter

    NASA Astrophysics Data System (ADS)

    Adams, M.; Bastin, A.; Coutrakon, G.; Glass, H.; Jaffe, D.; Kirz, J.; McCarthy, R.; Hubbard, J. R.; Mangeot, Ph.; Mullie, J.; Peisert, A.; Tichit, J.; Bouclier, R.; Charpak, G.; Santiard, J. C.; Sauli, F.; Crittenden, J.; Hsiung, Y.; Kaplan, D.; Brown, C.; Childress, S.; Finley, D.; Ito, A.; Jonckheere, A.; Jöstlein, H.; Lederman, L.; Orava, R.; Smith, S.; Sugano, K.; Ueno, K.; Maki, A.; Hemmi, Y.; Miyake, K.; Nakamura, T.; Sasao, N.; Sakai, Y.; Gray, R.; Plaag, R.; Rothberg, J.; Rutherfoord, J.; Young, K.

    1983-11-01

    The operating large aperture ring-imaging Cherenkov detector from the FNAL experiment E605 is described. Cherenkov ultraviolet photons are detected with a multi-step avalanche chamber using a He/TEA gas mixture and π/K/p separation is obtained from 50 to 200 GeV/ c.

  11. The system of EAS time analysis

    NASA Technical Reports Server (NTRS)

    Khalafyan, A. Z.; Oganezova, J. S.; Bashindjaghayan, G. L.; Mkhitaryan, V. M.; Sinev, N. B.; Sarycheva, L. I.

    1985-01-01

    The extensive air showers' (EAS) front shape, angle of incidence, disk thickness, particle distribution along the shower, on the delayed and EAS front advancing particles were determined. The suggested system of the EAS time analysis allows determination of the whole EAS longitudinal structure at the observation points. The information from the detectors is continuously recorded in the memory with the memory cell switching in 5 ns, this enables fixation of the moment of pulse input from the detector with an accuracy to + or - 2.5 ns. Along with the fast memory, a slow memory with the cell switching in 1 micron s is introduced in the system, this permits observation of relatively large time intervals with respect to the trigger pulse with an appropriately lower accuracy.

  12. The identification of gamma ray induced EAS

    NASA Technical Reports Server (NTRS)

    Blake, P. R.; Nash, W. F.

    1985-01-01

    Some of the penetrating particles in gamma-induced EAS from Cygnus X-3 observed by a single layer of flash-bulbs under 880 g cm/2 concrete, may be punched through photons rather than muons. An analysis of the shielded flash-tube response detected from EAS is presented. The penetration of the electro-magnetic component through 20 cm of Pb is observed at core distances approx. 10 m.

  13. Cosmic ray studies with a gas Cherenkov counter in association with an ionization spectrometer

    NASA Technical Reports Server (NTRS)

    Balasubrahmanyan, V. K.; Ormes, J. F.; Arens, J. F.; Siohan, F.; Yodh, G. B.; Simon, M.; Spiegelhauer, H.

    1980-01-01

    The results from a balloon-borne gas Cherenkov counter (threshold 16.5 GeV/nucleon) and an ionization spectrometer are presented. The gas Cherenkov counter provides an absolute energy distribution for the response of the calorimeter for 5 or = Z 26 nuclei of cosmic rays. The contribution of scintillation to the gas Cherenkov pulse height was obtained by independently selecting particles below the gas Cherenkov threshold using the ionization spectrometer. Energy spectra were derived by minimizing the chi squared between Monte Carlo simulted data and flight data. Best fit power laws, dN/dE = AE-gamma, were determined for C, N, O, Ne, Mg, and Si. The power laws, all consistent with E (-2.7) are not good fits to the data. A better fit is obtained using the spectrum derived from the spectrometer. The data from the ionization calorimeter and the gas Cherenkov are thus completely self-consistent.

  14. Cherenkov Ring Imaging Detector front-end electronics

    SciTech Connect

    Antilogus, P.; Aston, D.; Bienz, T.; Bird, F.; Dasu, S.; Dunwoodie, W.; Hallewell, G.; Kawahara, H.; Kwon, Y.; Leith, D.; Marshall, D.; Muller, D.; Nagamine, T.; Oxoby, G.; Ratcliff, B.; Rensing, P.; Schultz, D.; Shapiro, S.; Simopoulos, C.; Solodov, E.; Suekane, F.; Toge, N.; Va'Vra, J.; Williams, S. ); Wilson, R.J.; Whitaker, J.S. . Dept.

    1990-10-01

    The SLD Cherenkov Ring Imaging Detector use a proportional wire detector for which a single channel hybrid has been developed. It consists of a preamplifier, gain selectable amplifier, load driver amplifier, power switching, and precision calibrator. For this hybrid, a bipolar, semicustom integrated circuit has been designed which includes video operational amplifiers for two of the gain stages. This approach allows maximization of the detector volume, allows DC coupling, and enables gain selection. System tests show good noise performance, calibration precision, system linearity, and signal shape uniformity over the full dynamic range. 10 refs., 8 figs.

  15. The ring imaging Cherenkov detector for Fermilab experiment 665

    SciTech Connect

    Coutrakon, G.B.; Dhawan, S.; Schuler, P.

    1988-02-01

    The authors describe a ring imaging Cherenkov counter (RICH) which uses a multiwire proportional chamber (MWPC) with cathode pad readout as a UV photon detector. The detector has 10800 pads, each connected to a charge sensitive amplifier, within an area of 55 x 95 cm/sup 2/. The detector offers high data rate capability and a chamber sensitive time of less than 250 nsec. In addition, the detector has 1 mm spatial resolution and a multi-hit capability of about 50 photons/event.

  16. Modified energy-momentum conservation laws and vacuum Cherenkov radiation

    NASA Astrophysics Data System (ADS)

    Carmona, J. M.; Cortés, J. L.; Romeo, B.

    2015-12-01

    We present a general parametrization for the leading order terms in a momentum power expansion of a non-universal Lorentz-violating, but rotational invariant, kinematics and its implications for two-body decay thresholds. The considered framework includes not only modified dispersion relations for particles, but also modified energy-momentum conservation laws, something which goes beyond effective field theory. As a particular and relevant example, bounds on the departures from special relativistic kinematics from the non-observation of vacuum Cherenkov radiation are discussed and compared with those obtained within the effective field theory scenario.

  17. The fluid systems for the SLD Cherenkov ring imaging detector

    SciTech Connect

    Abe, K.; Hasegawa, K.; Hasegawa, Y.; Iwasaki, Y.; Suekane, F.; Yuta, H.; Antilogus, P.; Aston, D.; Bienz, T.; Bird, F.; Dasu, S.; Dolinsky, S.; Dunwoodie, W.; Hallewell, G.; Kawahara, H.; Kwon, Y.; Leith, D.W.G.S.; McCulloch, M.; McShurley, D.; Mueller, G.; Muller, D.; Nagamine, T.; Pavel, T.J.; Peterson, H.; Ratcliff, B.; Reif, R.; Rensing, P.; Schultz, D.; Shapiro, S.; Shaw, H.; Simopoulos, C.; Solodov, E.; Toge, N.; Vavra, J.; Watt, R.; Weber, T.; Williams, S.H.; Baird, K.; Jacques, P.; Kalelkar, M.; Plano, R.; Stamer, P.; Word, G.; Bean, A.; Caldwell, D.O.; Duboscq, J.; Huber, J.; Lu, A.; Mathys, L.; McHugh, S.; Yellin, S.; Ben-David, R.; Manly, S.; Snyder, J.; Turk, J.; Cavalli-Sforza, M.; Coyle, P.; Coyne, D.; Gagnon, P.; Liu, X.; Schneider, M.; Williams, D.A.; Coller, J.; Shank, J.T.; Whitaker, J.S.; d`Oliveira, A.; Johnson, R.A.; Martinez, J.; Nussbaum, M.; Santha, A.K.S.; Sokoloff, M.D.; Stockdale, I.; Wilson, R.J.

    1992-10-01

    We describe the design and operation of the fluid delivery, monitor and control systems for the SLD barrel Cherenkov Ring Imaging Detector (CRID). The systems deliver drift gas (C{sub 2}H{sub 6} + TMAE), radiator gas (C{sub 5}F{sub 12} + N{sub 2}) and radiator liquid (C{sub 6}F{sub 14}). Measured critical quantities such as electron lifetime in the drift gas and ultra-violet (UV) transparencies of the radiator fluids, together with the operational experience, are also reported.

  18. A high-efficiency focusing Cherenkov radiation detector

    SciTech Connect

    Lewis, K.; Moran, M.J.; Hall, J. ); Graser, M. )

    1992-03-01

    A new design uses advanced technology to produce an efficient, high-bandwidth Cherenkov detector for relativistic charged particles. The detector consists of a diamond-lathe machined ultraviolet-grade Lucite radiator, a parabolic focusing mirror, and a photodiode with an S-20 cathode. This article discusses some details of the detector design and describes preliminary measurements of its response characteristics. The data show the detector to have an overall gain of {approx}76 signal electrons per incident electron and a photodiode-limited response time of {approx}450 ps.

  19. Corrugated capillary as THz Cherenkov Smith-Purcell radiator

    NASA Astrophysics Data System (ADS)

    Lekomtsev, K. V.; Aryshev, A. S.; Tishchenko, A. A.; Ponomarenko, A. A.; Sukharev, V. M.; Terunuma, N.; Urakawa, J.; Strikhanov, M. N.

    2016-07-01

    In this article we discussed Particle In Cell electromagnetic simulations and mechanical design of dielectric capillaries that produce THz Cherenkov Smith-Purcell radiation (ChSPR), arising when a femtosecond electron multi-bunch beam propagates through corrugated and non-corrugated dielectric capillaries with metallic radiation reflectors. We investigated the influence of the four-bunch beam on the SPR field spectrum and on the ChSPR power spectrum, and the influence of the non-central beam propagation on the ChSPR power spectrum. We also discussed the design and assembly of the capillaries, constructed as sets of cylindrical rings.

  20. Tagging spallation backgrounds with showers in water Cherenkov detectors

    NASA Astrophysics Data System (ADS)

    Li, Shirley Weishi; Beacom, John F.

    2015-11-01

    Cosmic-ray muons and especially their secondaries break apart nuclei ("spallation") and produce fast neutrons and beta-decay isotopes, which are backgrounds for low-energy experiments. In Super-Kamiokande, these beta decays are the dominant background in 6-18 MeV, relevant for solar neutrinos and the diffuse supernova neutrino background. In a previous paper, we showed that these spallation isotopes are produced primarily in showers, instead of in isolation. This explains an empirical spatial correlation between a peak in the muon Cherenkov light profile and the spallation decay, which Super-Kamiokande used to develop a new spallation cut. However, the muon light profiles that Super-Kamiokande measured are grossly inconsistent with shower physics. We show how to resolve this discrepancy and how to reconstruct accurate profiles of muons and their showers from their Cherenkov light. We propose a new spallation cut based on these improved profiles and quantify its effects. Our results can significantly benefit low-energy studies in Super-Kamiokande, and will be especially important for detectors at shallower depths, like the proposed Hyper-Kamiokande.

  1. The HERA-B ring imaging Cherenkov counter

    NASA Astrophysics Data System (ADS)

    Ariño, I.; Bastos, J.; Broemmelsiek, D.; Carvalho, J.; Chmeissani, M.; Conde, P.; Davila, J.; Dujmić, D.; Eckmann, R.; Garrido, L.; Gascon, D.; Hamacher, T.; Gorišek, A.; Ivaniouchenkov, I.; Ispirian, M.; Karabekian, S.; Kim, M.; Korpar, S.; Križan, P.; Kupper, S.; Lau, K.; Maas, P.; McGill, J.; Miquel, R.; Murthy, N.; Peralta, D.; Pestotnik, R.; Pyrlik, J.; Ramachandran, S.; Reeves, K.; Rosen, J.; Schmidt-Parzefall, W.; Schwarz, A.; Schwitters, R. F.; Siero, X.; Starič, M.; Stanovnik, A.; Škrk, D.; Živko, T.

    2004-01-01

    The HERA-B RICH uses a radiation path length of 2.8 m in C 4F 10 gas and a large 24 m2 spherical mirror for imaging Cherenkov rings. The photon detector consists of 2240 Hamamatsu multi-anode photomultipliers with about 27 000 channels. A 2:1 reducing two-lens telescope in front of each photomultiplier tube increases the sensitive area at the expense of increased pixel size, resulting in a contribution to the resolution which roughly matches that of dispersion. The counter was completed in January of 1999, and its performance has been steady and reliable over the years it has been in operation. The design performance of the Ring Imaging Cherenkov counter was fully reached: the average number of detected photons in the RICH for a β=1 particle was found to be 33 with a single-hit resolution of 0.7 and 1 mrad in the fine and coarse granularity regions, respectively.

  2. Probing the inert doublet dark matter model with Cherenkov telescopes

    NASA Astrophysics Data System (ADS)

    Garcia-Cely, Camilo; Gustafsson, Michael; Ibarra, Alejandro

    2016-02-01

    We present a detailed study of the annihilation signals of the inert dark matter doublet model in its high mass regime. Concretely, we study the prospects to observe gamma-ray signals of the model in current and projected Cherenkov telescopes taking into account the Sommerfeld effect and including the contribution to the spectrum from gamma-ray lines as well as from internal bremsstrahlung. We show that present observations of the galactic center by the H.E.S.S. instrument are able to exclude regions of the parameter space that give the correct dark matter relic abundance. In particular, models with the charged and the neutral components of the inert doublet nearly degenerate in mass have strong gamma-ray signals. Furthermore, for dark matter particle masses above 1 TeV, we find that the non-observation of the continuum of photons generated by the hadronization of the annihilation products typically give stronger constraints on the model parameters than the sharp spectral features associated to annihilation into monochromatic photons and the internal bremsstrahlung process. Lastly, we also analyze the interplay between indirect and direct detection searches for this model, concluding that the prospects for the former are more promising. In particular, we find that the upcoming Cherenkov Telescope Array will be able to probe a significant part of the high mass regime of the model.

  3. The water Cherenkov detectors of the HAWC Observatory

    NASA Astrophysics Data System (ADS)

    Longo, Megan; Mostafa, Miguel

    2012-10-01

    The High Altitude Water Cherenkov (HAWC) observatory is a very high-energy gamma-ray detector which is currently under construction at 4100 m in Sierra Negra, Mexico. The observatory will be composed of an array of 300 Water Cherenkov Detectors (WCDs). Each WCD consists of a 5 m tall by 7.3 m wide steel tank containing a hermetically sealed plastic bag, called a bladder, which is filled with 200,000 liters of purified water. The detectors are each equipped with four upward-facing photomultiplier tubes (PMTs), anchored to the bottom of the bladder. At Colorado State University (CSU) we have the only full-size prototype outside of the HAWC site. It serves as a testbed for installation and operation procedures for the HAWC observatory. The WCD at CSU has been fully operational since March 2011, and has several components not yet present at the HAWC site. In addition to the four HAWC position PMTs, our prototype has three additional PMTs, including one shrouded (dark) PMT. We also have five scintillator paddles, four buried underneath the HAWC position PMTs, and one freely moving paddle above the volume of water. These extra additions will allow us to work on muon reconstruction with a single WCD. We will describe the analysis being done with the data taken with the CSU prototype, its impact on the HAWC detector, and future plans for the prototype.

  4. Oscillation of Very Low Energy Atmospheric Neutrinos

    SciTech Connect

    Peres, Orlando L. G.

    2010-03-30

    We discuss the oscillation effects of sub-sub-GeV atmospheric neutrinos, the sample with energies E < or approx. 100 MeV. The energy spectra of the e-like events in water Cherenkov detectors are computed and dependence of the spectra on the 2-3 mixing angle, theta{sub 23}, the 1-3 mixing and CP-violation phase are studied.

  5. Ultra-high resolution of radiocesium distribution detection based on Cherenkov light imaging

    NASA Astrophysics Data System (ADS)

    Yamamoto, Seiichi; Ogata, Yoshimune; Kawachi, Naoki; Suzui, Nobuo; Yin, Yong-Gen; Fujimaki, Shu

    2015-03-01

    After the nuclear disaster in Fukushima, radiocesium contamination became a serious scientific concern and research of its effects on plants increased. In such plant studies, high resolution images of radiocesium are required without contacting the subjects. Cherenkov light imaging of beta radionuclides has inherently high resolution and is promising for plant research. Since 137Cs and 134Cs emit beta particles, Cherenkov light imaging will be useful for the imaging of radiocesium distribution. Consequently, we developed and tested a Cherenkov light imaging system. We used a high sensitivity cooled charge coupled device (CCD) camera (Hamamatsu Photonics, ORCA2-ER) for imaging Cherenkov light from 137Cs. A bright lens (Xenon, F-number: 0.95, lens diameter: 25 mm) was mounted on the camera and placed in a black box. With a 100-μm 137Cs point source, we obtained 220-μm spatial resolution in the Cherenkov light image. With a 1-mm diameter, 320-kBq 137Cs point source, the source was distinguished within 2-s. We successfully obtained Cherenkov light images of a plant whose root was dipped in a 137Cs solution, radiocesium-containing samples as well as line and character phantom images with our imaging system. Cherenkov light imaging is promising for the high resolution imaging of radiocesium distribution without contacting the subject.

  6. The array for EAS neutron component detection

    NASA Astrophysics Data System (ADS)

    Gromushkin, D.; Alekseenko, V.; Petrukhin, A.; Shchegolev, O.; Stenkin, Yu; Stepanov, V.; Yashin, I.; Zadeba, E.

    2014-08-01

    The idea of a novel type detector array is the following: delayed thermal neutrons generated by hadronic component of Extensive Air Showers (EAS) can be detected over the whole array area using special electron-neutron detectors (en-detectors). The array PRISMA-32 consists of 32 en-detectors, deployed over the area of 450 m2. En-detectors are able to detect two main EAS components: electromagnetic one in a case of a synchronous passage of several charged particles, and hadronic component through thermal neutron captures. Detectors are based on a specialized inorganic scintillator, being a granulated alloy of ZnS(Ag) with LiF, enriched up to 90% with 6Li isotope. The array is triggered by the electromagnetic component of EAS, and provides information about the energy deposit (mostly electrons) and delayed neutrons accompanying the EAS within 20 ms after the trigger. During 2 years of operation more than 105 events were recorded. Examples of EAS detection are presented.

  7. First Year Operational Experience with the Cherenkov Detector (DIRC) of BaBar

    SciTech Connect

    Spanier, Stefane

    2000-04-21

    The DIRC (acronym for Detection of Internally Reflected Cherenkov (light)) is a new type of Cherenkov ring imaging detector based on total internal reflection that is used for the first time in the BaBar detector at PEP-II ring of SLAC. The Cherenkov radiators are long rectangular bars made of synthetic fused silica. The photon detector is a water tank equipped with an array of 10,752 conventional photomultipliers. The first year operational experience in the BaBar detector is presented using cosmic data and collision data in the energy region of the Upsilon(4S) resonance.

  8. First year operational experience with the Cherenkov Detector (DIRC) of BaBar

    SciTech Connect

    Adam, I.; BaBar Collaboration

    2000-04-01

    The DIRC (acronym for Detection of Internally Reflected Cherenkov (light)) is a new type of Cherenkov ring imaging detector based on total internal reflection that is used for the first time in the BaBar detector at PEP-II ring of SLAC. The Cherenkov radiators are long rectangular bars made of synthetic fused silica. The photon detector is a water tank equipped with an array of 10,752 conventional photomultipliers. The first year operational experience in the BaBar detector is presented using cosmic data and collision data in the energy region of the Y(4s) resonance.

  9. Design, transport, and installation of autonomous Cherenkov detectors at high altitude

    NASA Astrophysics Data System (ADS)

    Rubén Calderón Cueva, Mario; Alejandro Vasquez, Nicolas; Martínez, Oscar; Carrera, Edgar; Cazar, Dennis; Audelo, Mario; Mantilla, Cristina; Quishpe, Raquel

    2015-08-01

    Ecuador, as a member of the Latin American Giant Observatory (LAGO), wishes to expand the understanding of astroparticle physics and space weather by the installation of Water Cherenkov detectors at high altitude. The challenge for such devices lies on their transport to the remote areas of operation, the autonomy of their electrical power supply, the robustness of their data transmission system, their remote operation stability, and the reliability of the water integrity for long periods of time. LAGO Ecuador features several studies of gamma ray bursts and high energy astrophysical sources, as well as of space weather. Based on these studies, we develop a feasibility study for the design, installation, operation and maintenance of the aforementioned devices in Papallacta, Chimborazo and Cruz Loma in the Ecuadorean highlands. As the atmospheric absorption, and so the area of detection to be instrumented, is significantly reduced with the altitude, the easy access to locations higher than 4000 m a.s.l. is one of the main advantages of the Ecuadorean Andes for the installation of these facilities.

  10. Selective Filtration of Gadolinium Trichloride for Use in Neutron Detection in Large Water Cherenkov Detectors

    SciTech Connect

    Vagins, Mark R.

    2013-04-10

    Water Cherenkov detectors have been used for many years as inexpensive, effective detectors for neutrino interactions and nucleon decay searches. While many important measurements have been made with these detectors a major drawback has been their inability to detect the absorption of thermal neutrons. We believe an inexpensive, effective technique could be developed to overcome this situation via the addition to water of a solute with a large neutron cross section and energetic gamma daughters which would make neutrons detectable. Gadolinium seems an excellent candidate especially since in recent years it has become very inexpensive, now less than $8 per kilogram in the form of commercially-available gadolinium trichloride, GdCl{sub 3}. This non-toxic, non-reactive substance is highly soluble in water. Neutron capture on gadolinium yields a gamma cascade which would be easily seen in detectors like Super-Kamiokande. We have been investigating the use of GdCl{sub 3} as a possible upgrade for the Super-Kamiokande detector with a view toward improving its performance as a detector for atmospheric neutrinos, supernova neutrinos, wrong-sign solar neutrinos, reactor neutrinos, proton decay, and also as a target for the coming T2K long-baseline neutrino experiment. This focused study of selective water filtration and GdCl{sub 3} extraction techniques, conducted at UC Irvine, followed up on highly promising benchtop-scale and kiloton-scale work previously carried out with the assistance of 2003 and 2005 Advanced Detector Research Program grants.

  11. Intensity Interferometry with Cherenkov Telescope Arrays: Prospects for submilliarcsecond optical imaging

    NASA Astrophysics Data System (ADS)

    Dravins, D.

    2014-04-01

    Intensity interferometry measures the second-order coherence of light. Very rapid (nanosecond) fluctuations are correlated between separate telescopes, without any optical connection. This makes the method insensitive to atmospheric turbulence and optical imperfections, permitting observations over long baselines, and at short wavelengths. The required large telescopes are becoming available as those primarily erected to study gamma rays: the planned Cherenkov Telescope Array (https://www.cta-observatory.org/) envisions many tens of telescopes distributed over a few square km. Digital signal handling enables very many baselines to be simultaneously synthesized between many pairs of telescopes, while stars may be tracked across the sky with electronic time delays, synthesizing an optical interferometer in software. Simulations indicate limiting magnitudes around m(v)=8, reaching a resolution of 30 microarcseconds in the violet. Since intensity interferometry provides only the modulus (not phase) of any spatial frequency component of the source image, image reconstruction requires phase retrieval techniques. As shown in simulations, full two-dimensional images can be retrieved, provided there is an extensive coverage of the (u,v)-plane, such as will be available once the number of telescopes reaches numbers on the order of ten.

  12. Theoretical study of EAS hadronic structure

    NASA Technical Reports Server (NTRS)

    Popova, L.

    1985-01-01

    The structure of extensive air showers (EAS) is determined mainly by the energetic hadrons. They are strongly collimated in the core of the shower and essential difficulties are encountered for resolution of individual hadrons. The properties for resolution are different from the variety of hadron detectors used in EAS experiments. This is the main difficulty in obtaining a general agreement between actually registered data with different detectors. The most plausible source for disagreement is the uncertainty in determination of the energy of individual hadrons. This research demonstrates that a better agreement can be obtained with the average tendency of hadronic measurements if one assumes a larger coefficient of inelasticity and stronger energy increase of the total inelastic cross section in high energy pion interactions. EAS data above 10 to the 5th power GeV are revealing a faster development of hadronic cascades in the air then can be expected by extrapolating the parameters of hadron interactions obtained in accelerator measurements.

  13. 36 CFR 1010.11 - Preparation of an EA.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... specified in 40 CFR 1506.6. (d) Mitigated FONSI. If an EA is completed and the NEPA Compliance Coordinator... alternatives and the proposal. The EA shall contain brief discussions of the following topics: (1) Purpose...

  14. 47 CFR 90.761 - EA and Regional licenses.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... Regional licenses. (a) EA licenses for spectrum blocks listed in Table 2 of § 90.721(b) are available in 175 Economic Areas (EAs) as defined in § 90.7. (b) Regional licenses for spectrum blocks listed...

  15. 47 CFR 90.761 - EA and Regional licenses.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... Regional licenses. (a) EA licenses for spectrum blocks listed in Table 2 of § 90.721(b) are available in 175 Economic Areas (EAs) as defined in § 90.7. (b) Regional licenses for spectrum blocks listed...

  16. 47 CFR 90.761 - EA and Regional licenses.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... Regional licenses. (a) EA licenses for spectrum blocks listed in Table 2 of § 90.721(b) are available in 175 Economic Areas (EAs) as defined in § 90.7. (b) Regional licenses for spectrum blocks listed...

  17. 47 CFR 90.761 - EA and Regional licenses.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... Regional licenses. (a) EA licenses for spectrum blocks listed in Table 2 of § 90.721(b) are available in 175 Economic Areas (EAs) as defined in § 90.7. (b) Regional licenses for spectrum blocks listed...

  18. 47 CFR 90.761 - EA and Regional licenses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Regional licenses. (a) EA licenses for spectrum blocks listed in Table 2 of § 90.721(b) are available in 175 Economic Areas (EAs) as defined in § 90.7. (b) Regional licenses for spectrum blocks listed...

  19. Prototype of a production system for Cherenkov Telescope Array with DIRAC

    NASA Astrophysics Data System (ADS)

    Arrabito, L.; Bregeon, J.; Haupt, A.; Graciani Diaz, R.; Stagni, F.; Tsaregorodtsev, A.

    2015-12-01

    The Cherenkov Telescope Array (CTA) — an array of many tens of Imaging Atmospheric Cherenkov Telescopes deployed on an unprecedented scale — is the next generation instrument in the field of very high energy gamma-ray astronomy. CTA will operate as an open observatory providing data products to the scientific community. An average data stream of about 10 GB/s for about 1000 hours of observation per year, thus producing several PB/year, is expected. Large CPU time is required for data-processing as well for massive Monte Carlo simulations needed for detector calibration purposes. The current CTA computing model is based on a distributed infrastructure for the archive and the data off-line processing. In order to manage the off-line data-processing in a distributed environment, CTA has evaluated the DIRAC (Distributed Infrastructure with Remote Agent Control) system, which is a general framework for the management of tasks over distributed heterogeneous computing environments. In particular, a production system prototype has been developed, based on the two main DIRAC components, i.e. the Workload Management and Data Management Systems. After three years of successful exploitation of this prototype, for simulations and analysis, we proved that DIRAC provides suitable functionalities needed for the CTA data processing. Based on these results, the CTA development plan aims to achieve an operational production system, based on the DIRAC Workload Management System, to be ready for the start of CTA operation phase in 2017-2018. One more important challenge consists of the development of a fully automatized execution of the CTA workflows. For this purpose, we have identified a third DIRAC component, the so-called Transformation System, which offers very interesting functionalities to achieve this automatisation. The Transformation System is a ’data-driven’ system, allowing to automatically trigger data-processing and data management operations according to pre

  20. Vacuum Cherenkov radiation and bremsstrahlung from disformal couplings

    NASA Astrophysics Data System (ADS)

    van de Bruck, Carsten; Burrage, Clare; Morrice, Jack

    2016-08-01

    The simplest way to modify gravity is to extend the gravitational sector to include an additional scalar degree of freedom. The most general metric that can be built in such a theory includes disformal terms, so that standard model fields move on a metric which is the sum of the space time metric and a tensor constructed from first derivatives of the scalar. In such a theory gravitational waves and photons can propagate at different speeds, and these can in turn be different from the maximum speed limit for matter particles. In this work we show that disformal couplings can cause charged particles to emit Cherenkov radiation and bremsstrahlung apparently in vacuum, depending on the background evolution of the scalar field. We discuss the implications of this for observations of cosmic rays, and the constraints that arise for models of dark energy with disformal couplings.

  1. Status of Coherent Cherenkov Wakefield Experiment at UCLA

    SciTech Connect

    Cook, A. M.; Knyazik, A.; Rosenzweig, J. B.; Tikhoplav, R.; Travish, G.; Williams, O. B.

    2009-01-22

    Coherent Cherenkov radiation (CCR) wakefields are produced when a compressed electron beam travels along the axis of a hollow cylindrical dielectric tube. In a dielectric wakefield accelerator (DWA) these wakefields accelerate either a trailing electron bunch or the tail of the driving bunch, depending on the modal structure of the radiation. For an appropriate choice of dielectric structure geometry and beam parameters the device operates in a single-mode regime, producing sinusoidal wakefields with wavelengths in the THz range. We report on preliminary results of an experiment at UCLA studying the potential of a DWA structure to produce high-power, narrow-band THz radiation. First measurements include observation of 1 MW peak-power pulses of coherent broadband radiation from a compact dipole beam dump magnet.

  2. Suppressing the numerical Cherenkov radiation in the Yee numerical scheme

    NASA Astrophysics Data System (ADS)

    Nuter, Rachel; Tikhonchuk, Vladimir

    2016-01-01

    The next generation of laser facilities will routinely produce relativistic particle beams from the interaction of intense laser pulses with solids and/or gases. Their modeling with Particle-In-Cell (PIC) codes needs dispersion-free Maxwell solvers in order to properly describe the interaction of electromagnetic waves with relativistic particles. A particular attention is devoted to the suppression of the numerical Cherenkov instability, responsible for the noise generation. It occurs when the electromagnetic wave is artificially slowed down because of the finite mesh size, thus allowing for the high energy particles to propagate with super-luminous velocities. In the present paper, we show how a slight increase of the light velocity in the Maxwell's equations enables to suppress this instability while keeping a good overall precision of calculations.

  3. Coherent Cherenkov radiation as an intense THz source

    NASA Astrophysics Data System (ADS)

    Bleko, V.; Karataev, P.; Konkov, A.; Kruchinin, K.; Naumenko, G.; Potylitsyn, A.; Vaughan, T.

    2016-07-01

    Diffraction and Cherenkov radiation of relativistic electrons from a dielectric target has been proposed as mechanism for production of intense terahertz (THz) radiation. The use of an extremely short high-energy electron beam of a 4th generation light source (X-ray free electron laser) appears to be very promising. A moderate power from the electron beam can be extracted and converted into THz radiation with nearly zero absorption losses. The initial experiment on THz observation will be performed at CLARA/VELA FEL test facility in the UK to demonstrate the principle to a wider community and to develop the radiator prototype. In this paper, we present our theoretical predictions (based on the approach of polarization currents), which provides the basis for interpreting the future experimental measurements. We will also present our hardware design and discuss a plan of the future experiment.

  4. Application of Geiger-mode photosensors in Cherenkov detectors

    NASA Astrophysics Data System (ADS)

    Gamal, Ahmed; Paul, Bühler; Michael, Cargnelli; Roland, Hohler; Johann, Marton; Herbert, Orth; Ken, Suzuki

    2011-05-01

    Silicon-based photosensors (SiPMs) working in the Geiger-mode represent an elegant solution for the readout of particle detectors working at low-light levels like Cherenkov detectors. Especially the insensitivity to magnetic fields makes this kind of sensors suitable for modern detector systems in subatomic physics which are usually employing magnets for momentum resolution. We are characterizing SiPMs of different manufacturers for selecting sensors and finding optimum operating conditions for given applications. Recently we designed and built a light concentrator prototype with 8×8 cells to increase the active photon detection area of an 8×8 SiPM (Hamamatsu MPPC S10931-100P) array. Monte Carlo studies, measurements of the collection efficiency, and tests with the MPPC were carried out. The status of these developments are presented.

  5. Cherenkov sound on a surface of a topological insulator

    NASA Astrophysics Data System (ADS)

    Smirnov, Sergey

    2013-11-01

    Topological insulators are currently of considerable interest due to peculiar electronic properties originating from helical states on their surfaces. Here we demonstrate that the sound excited by helical particles on surfaces of topological insulators has several exotic properties fundamentally different from sound propagating in nonhelical or even isotropic helical systems. Specifically, the sound may have strictly forward propagation absent for isotropic helical states. Its dependence on the anisotropy of the realistic surface states is of distinguished behavior which may be used as an alternative experimental tool to measure the anisotropy strength. Fascinating from the fundamental point of view backward, or anomalous, Cherenkov sound is excited above the critical angle π/2 when the anisotropy exceeds a critical value. Strikingly, at strong anisotropy the sound localizes into a few forward and backward beams propagating along specific directions.

  6. About a Gadolinium-doped Water Cherenkov LAGUNA Detector

    NASA Astrophysics Data System (ADS)

    Labarga, Luis

    2010-11-01

    Water Cherenkov (wC) detectors are extremely powerful apparatuses for scientific research. Nevertheless they lack of neutron tagging capabilities, which translates, mainly, into an inability to identify the anti-matter nature of the reacting incoming anti-neutrino particles. A solution was proposed by R. Beacon and M. Vagins back in 2004: by dissolving in the water a compound with nucleus with very large cross section for neutron capture like the Gadolinium, with a corresponding emission of photons of enough energy to be detected, they can tag thermal neutrons with an efficiency larger than 80%. In this talk we detail the technique and its implications in the measurement capabilities and, as well, the new backgrounds induced. We discuss the improvement on their physics program, also for the case of LAGUNA type detectors. We comment shortly the status of the pioneering R&D program of the Super-Kamiokande Collaboration towards dissolving a Gadolinium compound in its water.

  7. About a Gadolinium-doped Water Cherenkov LAGUNA Detector

    SciTech Connect

    Labarga, Luis

    2010-11-24

    Water Cherenkov (wC) detectors are extremely powerful apparatuses for scientific research. Nevertheless they lack of neutron tagging capabilities, which translates, mainly, into an inability to identify the anti-matter nature of the reacting incoming anti-neutrino particles. A solution was proposed by R. Beacon and M. Vagins back in 2004: by dissolving in the water a compound with nucleus with very large cross section for neutron capture like the Gadolinium, with a corresponding emission of photons of enough energy to be detected, they can tag thermal neutrons with an efficiency larger than 80%. In this talk we detail the technique and its implications in the measurement capabilities and, as well, the new backgrounds induced. We discuss the improvement on their physics program, also for the case of LAGUNA type detectors. We comment shortly the status of the pioneering R and D program of the Super-Kamiokande Collaboration towards dissolving a Gadolinium compound in its water.

  8. The Ring Imaging Cherenkov Detector of the NA62 Experiment

    NASA Astrophysics Data System (ADS)

    Bucci, F.

    2012-08-01

    The NA62 experiment is designed to measure the branching ratio of the decay K+ -> π +ν bar {ν } with a 10% accuracy at the CERN SPS. To suppress the main background coming from the K+ → μ+ν decay, a Ring Imaging Cherenkov detector (RICH), able to separate π and μ in the momentum range between 15 and 35 GeV/c with a muon contamination in a pion sample < 10-2 is needed. The RICH must also have an unprecedented time resolution (100 ps) to disentangle accidental time 115sociatioDll of beam particles with pions. The last updates of the detector layout are presented along with the results of the beam tests of the RICH prototype: the muon misidentification probability was found to be 0. 7% and the time resolution < 100 ps in all the momentum range.

  9. EAS array of the NEVOD Experimental Complex

    NASA Astrophysics Data System (ADS)

    Yashin, I. I.; Amelchakov, M. B.; Ampilogov, N. V.; Barbashina, N. S.; Bogdanov, A. G.; Chiavassa, A.; Fomenko, S. V.; Kamlev, N. N.; Khokhlov, S. S.; Kindin, V. V.; Kokoulin, R. P.; Kompaniets, K. G.; Kutovoy, V. Yu; Likiy, O. I.; Mannocchi, G.; Ovchinnikov, V. V.; Petrukhin, A. A.; Saavedra, O.; Trinchero, G.; Shestakov, V. V.; Shulzhenko, I. A.; Shutenko, V. V.

    2015-08-01

    A new setup for registration of the electromagnetic component of the EAS at the “knee” region of the energy spectrum of primary cosmic rays (PCR) is now under construction on the basis of the experimental complex NEVOD-DECOR (Moscow, Russia). The EAS array detecting system has a cluster organization. Clusters are located in the MEPhI campus. The specific features of the array registering system that provides particle detection, data acquisition, cluster synchronization and events selection are discussed. The results of counter characteristics study are also presented.

  10. Characterization study of silica aerogel for Cherenkov imaging

    NASA Astrophysics Data System (ADS)

    Sallaz-Damaz, Y.; Derome, L.; Mangin-Brinet, M.; Loth, M.; Protasov, K.; Putze, A.; Vargas-Trevino, M.; Véziant, O.; Buénerd, M.; Menchaca-Rocha, A.; Belmont, E.; Vargas-Magaña, M.; Léon-Vargas, H.; Ortiz-Velàsquez, A.; Malinine, A.; Baraõ, F.; Pereira, R.; Bellunato, T.; Matteuzzi, C.; Perego, D. L.

    2010-03-01

    Different methods to measure the characteristics of silica aerogel tiles used as Cherenkov radiator in the CREAM and AMS experiments have been investigated to optimize the detector performances. The measurement accuracy dictated by the physics objectives on the velocity and charge resolutions set stringent requirements on the aerogel refractive index determination, namely Δn˜1.5×10-4 and Δn˜5×10-4 for the AMS and CREAM imagers, respectively. The matching of such accuracies for this material turned out to be a metrological challenge, and finally led to a full R&D program, to develop an appropriate characterization procedure. Preliminary studies performed with a standard refractive index measurement technique (laser beam deviation by a prism) have revealed a significant systematic index nonuniformity for the AMS tiles at a level (10-3), not acceptable considering the aimed accuracy. These large variations were confirmed in a beam test. A second method, mapping the transverse index gradient by deflection of a laser beam entering normally to the tile has then been developed. It is shown that this procedure is suitable to reach the required accuracy, at the price of using both methods combined. The several hundreds of tiles of the radiator plane of the CREAM and AMS Cherenkov imagers were characterized using a simplified procedure, however, appropriate for each case, compromising between the amount of work and the time available. The experimental procedures and set-ups used are described in the text, and the obtained results are reported.

  11. Optical properties of water for the Yangbajing water cherenkov detector

    NASA Astrophysics Data System (ADS)

    Gao, Shang-qi; Sun, Zhi-bin; Jiang, Yuan-da; Wang, Chao; Du, Ke-ming

    2011-08-01

    Cherenkov radiation is used to study the production of particles during collisions, cosmic rays detections and distinguishing between different types of neutrinos and electrons. The optical properties of water are very important to the research of Cherenkov Effect. Lambert-beer law is a method to study the attenuation of light through medium. In this paper, optical properties of water are investigated by use of a water attenuation performance test system. The system is composed of the light-emitting diode (LED) light source and the photon receiver models. The LED light source model provides a pulse light signal which frequency is 1 kHz and width is 100ns. In photon receiver model, a high sensitivity photomultiplier tube (PMT) is used to detect the photons across the water. Because the output voltage amplitude of PMT is weak which is from 80mv to 120mV, a low noise pre-amplifier is used to improve the detector precise. An effective detector maximum time window of PMT is 100ns for a long lifetime, so a peak holder circuit is used to hold the maximum peak amplitude of PMT for the induced photons signal before the digitalization. In order to reduce the noise of peak holder, a multi-pulse integration is used before the sampling of analog to digital converter. At last, the detector of photons from the light source to the PMT across the water is synchronized to the pulse width of the LED. In order to calculate the attenuation coefficient and attenuation length of water precisely, the attenuation properties of air-to-water boundary is considered in the calculation.

  12. Ionization and pulse lethargy effects in inverse Cherenkov accelerators

    SciTech Connect

    Sprangle, P.; Hubbard, R.F.,; Hafizi, B.,

    1997-05-01

    Ionization processes limit the accelerating gradient and place an upper limit on the pulse duration of the electromagnetic driver in the inverse Cherenkov accelerator (ICA). Group velocity slippage, i.e., pulse lethargy, on the other hand, imposes a lower limit on the pulse duration. These limits are obtained for two ICA configurations in which the electromagnetic driver (e.g., laser or millimeter wave source) is propagated in a waveguide that is (i) lined with a dielectric material or (ii) filled with a neutral gas. In either configuration the electromagnetic driving field is guided and has an axial electric field with phase velocity equal to the speed of light in vacuum, c. The intensity of the driver in the ICA, and therefore the acceleration gradient, is limited by tunneling and collisional ionization effects. Partial ionization of the dielectric liner or gas can lead to significant modification of the dispersive properties of the waveguide, altering the phase velocity of the accelerating field and causing particle slippage, thus disrupting the acceleration process. An additional limitation on the pulse duration is imposed since the group velocity of the driving pulse is less than c and the pulse slips behind the accelerated electrons. Hence for sufficiently short pulses the electrons outrun the pulse, terminating the acceleration. Limitations on the driver pulse duration and accelerating gradient, due to ionization and pulse lethargy, are estimated for the two ICA configurations. Maximum accelerating gradients and pulse durations are presented for a 10 {mu}m, 1 mm, and 1 cm wavelength electromagnetic driver. The combination of ionization and pulse lethargy effects impose severe limitations on the maximum energy gain in inverse Cherenkov accelerators. {copyright} {ital 1997} {ital The American Physical Society}

  13. 76 FR 8726 - EasTrans, LLC; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-15

    ... From the Federal Register Online via the Government Publishing Office ] DEPARTMENT OF ENERGY Federal Energy Regulatory Commission EasTrans, LLC; Notice of Filing Take notice that on February 4, 2011, EasTrans, LLC (EasTrans) filed a revised Statement of Operating Conditions (SOC) reflecting...

  14. Very high energy emission of Crab-like pulsars driven by the Cherenkov drift radiation

    NASA Astrophysics Data System (ADS)

    Osmanov, Z.

    2016-02-01

    In this paper, we study the generation of very high energy (VHE) emission in Crab-like pulsars driven by means of the feedback of Cherenkov drift waves on distribution of magnetospheric electrons. We have found that the unstable Cherenkov drift modes lead to the quasi-linear diffusion, keeping the pitch angles from vanishing, which in turn, maintains the synchrotron mechanism. Considering the Crab-like pulsars it has been shown that the growth rate of the Cherenkov drift instability is quite high, indicating high efficiency of the process. Analysing the mechanism for the typical parameters we have found that the Cherenkov drift emission from the extreme UV to hard X-rays is strongly correlated with the VHE synchrotron emission in the GeV band.

  15. Silica aerogel threshold Cherenkov counters for the JLab Hall A spectrometers: improvements and proposed modifications

    SciTech Connect

    Luigi Lagamba; Evaristo Cisbani; S. Colilli; R. Crateri; R. De Leo; Salvatore Frullani; Franco Garibaldi; F. Giuliani; M. Gricia; Mauro Iodice; Riccardo Iommi; A. Leone; M. Lucentini; A. Mostarda; E. Nappi; Roberto Perrino; L. Pierangeli; F. Santavenere; Guido M. Urciuoli

    2001-10-01

    Recently approved experiments at Jefferson Lab Hall A require a clean kaon identification in a large electron, pion, and proton background environment. To this end, improved performance is required of the silica aerogel threshold Cherenkov counters installed in the focal plane of the two Hall A spectrometers. In this paper we propose two strategies to improve the performance of the Cherenkov counters which presently use a hydrophilic aerogel radiator, and convey Cherenkov photons towards the photomultipliers by means of mirrors with a parabolic shape in one direction and flat in the other. The first strategy is aerogel baking. In the second strategy we propose a modification of the counter geometry by replacing the mirrors with a planar diffusing surface and by displacing in a different way the photomultipliers. Tests at CERN with a 5GeV/c multiparticle beam revealed that both the strategies are able to increase significantly the number of the detected Cherenkov photons and, therefore, the detector performance.

  16. A threshold gas Cherenkov detector for the Spin Asymmetries of the Nucleon Experiment

    NASA Astrophysics Data System (ADS)

    Armstrong, Whitney R.; Choi, Seonho; Kaczanowicz, Ed; Lukhanin, Alexander; Meziani, Zein-Eddine; Sawatzky, Brad

    2015-12-01

    We report on the design, construction, commissioning, and performance of a threshold gas Cherenkov counter in an open configuration, which operates in a high luminosity environment and produces a high photo-electron yield. Part of a unique open geometry detector package called the Big Electron Telescope Array (BETA), this Cherenkov counter served to identify scattered electrons and reject produced pions in an inclusive scattering experiment known as the Spin Asymmetries of the Nucleon Experiment (SANE), E07-003 at Jefferson Lab. The experiment consisted of a measurement of double spin asymmetries A∥ and A⊥ of a polarized electron beam impinging on a polarized ammonia target. The Cherenkov counter's performance is characterised by a yield of about 20 photoelectrons per electron or positron track. Thanks to this large number of photoelectrons per track, the Cherenkov counter had enough resolution to identify electron-positron pairs from the conversion of photons resulting mainly from π0 decays.

  17. Low-Noise Operation of All-Fiber Femtosecond Cherenkov Laser

    PubMed Central

    Liu, Xiaomin; Villanueva, Guillermo E.; Lægsgaard, Jesper; Møller, Uffe; Tu, Haohua; Boppart, Stephen A.; Turchinovich, Dmitry

    2013-01-01

    We investigate the noise properties of a femtosecond all-fiber Cherenkov radiation source with emission wavelength 600 nm, based on an Yb-fiber laser and a highly nonlinear photonic crystal fiber. A relative intensity noise as low as 103 dBc/Hz, corresponding to 2.48% pulse-to-pulse fluctuation in energy, is observed at the Cherenkov radiation output power of 4.3 mW, or 150 pJ-pulse energy. This pulse-to-pulse fluctuation is at least 10.6-dB lower compared to spectrally sliced supercontinuum sources traditionally used for ultrafast fiber-based generation at visible wavelengths. Low noise makes all-fiber Cherenkov sources promising for biophotonics applications such as multiphoton microscopy, where minimum pulse-to-pulse energy fluctuation is required. We present the dependency of the noise figure on both the Cherenkov radiation output power and its spectrum. PMID:24532961

  18. Simulated response of Cherenkov glass detectors to MeV photons

    SciTech Connect

    Hayward, J P; Bell, Zane W; Boatner, Lynn A; Hobbs, C. L.; Johnson, Rose E; Ramey, Joanne Oxendine; Jellison Jr, Gerald Earle

    2012-01-01

    Cherenkov detectors are widely used for par ticle identification in high-energy physics and for track imaging in astrophysics. Glass Cherenkov detectors that are sensitive to beta emissions originating from neutron activation have been demonstrated recently as a potential replacement for activation foils. In this work, we evaluate Cherenkov glass detectors for sensitivity and specificity to MeV photons through simulations using Geant4. The model has been previously compared with measurements of isotopic gamma sources. It includes Cherenkov gener ation, light transport, light collection, photoelectron pro duction and time response in photomultiplier tubes. The model incorporates measured, wavelength-dependent absorption and refractive index data. Simulations are con ducted for glasses the size of fabricated samples and also for the same glasses in monolithic, square-meter-size. Implications for selective detection of MeV photons are discussed.

  19. Performance comparisons between PCA-EA-LBG and PCA-LBG-EA approaches in VQ codebook generation for image compression

    NASA Astrophysics Data System (ADS)

    Tsai, Jinn-Tsong; Chou, Ping-Yi; Chou, Jyh-Horng

    2015-11-01

    The aim of this study is to generate vector quantisation (VQ) codebooks by integrating principle component analysis (PCA) algorithm, Linde-Buzo-Gray (LBG) algorithm, and evolutionary algorithms (EAs). The EAs include genetic algorithm (GA), particle swarm optimisation (PSO), honey bee mating optimisation (HBMO), and firefly algorithm (FF). The study is to provide performance comparisons between PCA-EA-LBG and PCA-LBG-EA approaches. The PCA-EA-LBG approaches contain PCA-GA-LBG, PCA-PSO-LBG, PCA-HBMO-LBG, and PCA-FF-LBG, while the PCA-LBG-EA approaches contain PCA-LBG, PCA-LBG-GA, PCA-LBG-PSO, PCA-LBG-HBMO, and PCA-LBG-FF. All training vectors of test images are grouped according to PCA. The PCA-EA-LBG used the vectors grouped by PCA as initial individuals, and the best solution gained by the EAs was given for LBG to discover a codebook. The PCA-LBG approach is to use the PCA to select vectors as initial individuals for LBG to find a codebook. The PCA-LBG-EA used the final result of PCA-LBG as an initial individual for EAs to find a codebook. The search schemes in PCA-EA-LBG first used global search and then applied local search skill, while in PCA-LBG-EA first used local search and then employed global search skill. The results verify that the PCA-EA-LBG indeed gain superior results compared to the PCA-LBG-EA, because the PCA-EA-LBG explores a global area to find a solution, and then exploits a better one from the local area of the solution. Furthermore the proposed PCA-EA-LBG approaches in designing VQ codebooks outperform existing approaches shown in the literature.

  20. Angular width of the Cherenkov radiation with inclusion of multiple scattering

    NASA Astrophysics Data System (ADS)

    Zheng, Jian

    2016-06-01

    Visible Cherenkov radiation can offer a method of the measurement of the velocity of charged particles. The angular width of the radiation is important since it determines the resolution of the velocity measurement. In this article, the angular width of Cherenkov radiation with inclusion of multiple scattering is calculated through the path-integral method, and the analytical expressions are presented. The condition that multiple scattering processes dominate the angular distribution is obtained.

  1. 47 CFR 11.32 - EAS Encoder.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... used for audio messages and at least one input port used for data messages. (3) Outputs. The encoder shall have at least one audio output port and at least one data output port. (4) Calibration. EAS... sent and deactivated at the End of Message code. (8) Spurious Response. All frequency...

  2. 24 CFR 50.31 - The EA.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 24 Housing and Urban Development 1 2011-04-01 2011-04-01 false The EA. 50.31 Section 50.31 Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development PROTECTION AND ENHANCEMENT OF ENVIRONMENTAL QUALITY Environmental Assessments and Related Reviews § 50.31 The...

  3. 24 CFR 50.31 - The EA.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 24 Housing and Urban Development 1 2013-04-01 2013-04-01 false The EA. 50.31 Section 50.31 Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development PROTECTION AND ENHANCEMENT OF ENVIRONMENTAL QUALITY Environmental Assessments and Related Reviews § 50.31 The...

  4. 24 CFR 50.31 - The EA.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 1 2014-04-01 2014-04-01 false The EA. 50.31 Section 50.31 Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development PROTECTION AND ENHANCEMENT OF ENVIRONMENTAL QUALITY Environmental Assessments and Related Reviews § 50.31 The...

  5. 24 CFR 50.31 - The EA.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 1 2010-04-01 2010-04-01 false The EA. 50.31 Section 50.31 Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development PROTECTION AND ENHANCEMENT OF ENVIRONMENTAL QUALITY Environmental Assessments and Related Reviews § 50.31 The...

  6. 24 CFR 50.31 - The EA.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 24 Housing and Urban Development 1 2012-04-01 2012-04-01 false The EA. 50.31 Section 50.31 Housing and Urban Development Office of the Secretary, Department of Housing and Urban Development PROTECTION AND ENHANCEMENT OF ENVIRONMENTAL QUALITY Environmental Assessments and Related Reviews § 50.31 The...

  7. TRANSPORT PROPERTY MEASUREMENTS OF HFC-236EA

    EPA Science Inventory

    The report gives results of an evaluation of transport properties of 1, 1, 1, 2, 3, 3-hexafluoropropane (HFC-236ea), with liquid viscosity and thermal conductivity being the two main transport properties of interest. In addition, the specific heat and density of refrigerant/lubri...

  8. TRANSPORT PROPERTY MEASUREMENTS OF HFC-236EA

    EPA Science Inventory

    The report gives results of an evaluation of transport properties of 1,1,1,2,3,3,-hexafluoropropane (HFC-236ea), with liquid viscosity and thermal conductivity being the two main transport properties of interest. In addition, the specific heat and density of refrigerant/lubrican...

  9. Angular distribution of Cherenkov radiation from relativistic heavy ions taking into account deceleration in the radiator

    NASA Astrophysics Data System (ADS)

    Bogdanov, O. V.; Fiks, E. I.; Pivovarov, Yu. L.

    2012-09-01

    Numerical methods are used to study the dependence of the structure and the width of the angular distribution of Vavilov-Cherenkov radiation with a fixed wavelength in the vicinity of the Cherenkov cone on the radiator parameters (thickness and refractive index), as well as on the parameters of the relativistic heavy ion beam (charge and initial energy). The deceleration of relativistic heavy ions in the radiator, which decreases the velocity of ions, modifies the condition of structural interference of the waves emitted from various segments of the trajectory; as a result, a complex distribution of Vavilov-Cherenkov radiation appears. The main quantity is the stopping power of a thin layer of the radiator (average loss of the ion energy), which is calculated by the Bethe-Bloch formula and using the SRIM code package. A simple formula is obtained to estimate the angular distribution width of Cherenkov radiation (with a fixed wavelength) from relativistic heavy ions taking into account the deceleration in the radiator. The measurement of this width can provide direct information on the charge of the ion that passes through the radiator, which extends the potentialities of Cherenkov detectors. The isotopic effect (dependence of the angular distribution of Vavilov-Cherenkov radiation on the ion mass) is also considered.

  10. Angular distribution of Cherenkov radiation from relativistic heavy ions taking into account deceleration in the radiator

    SciTech Connect

    Bogdanov, O. V. Fiks, E. I.; Pivovarov, Yu. L.

    2012-09-15

    Numerical methods are used to study the dependence of the structure and the width of the angular distribution of Vavilov-Cherenkov radiation with a fixed wavelength in the vicinity of the Cherenkov cone on the radiator parameters (thickness and refractive index), as well as on the parameters of the relativistic heavy ion beam (charge and initial energy). The deceleration of relativistic heavy ions in the radiator, which decreases the velocity of ions, modifies the condition of structural interference of the waves emitted from various segments of the trajectory; as a result, a complex distribution of Vavilov-Cherenkov radiation appears. The main quantity is the stopping power of a thin layer of the radiator (average loss of the ion energy), which is calculated by the Bethe-Bloch formula and using the SRIM code package. A simple formula is obtained to estimate the angular distribution width of Cherenkov radiation (with a fixed wavelength) from relativistic heavy ions taking into account the deceleration in the radiator. The measurement of this width can provide direct information on the charge of the ion that passes through the radiator, which extends the potentialities of Cherenkov detectors. The isotopic effect (dependence of the angular distribution of Vavilov-Cherenkov radiation on the ion mass) is also considered.

  11. New electronics for the Cherenkov Telescope Array (NECTAr)

    NASA Astrophysics Data System (ADS)

    Naumann, C. L.; Delagnes, E.; Bolmont, J.; Corona, P.; Dzahini, D.; Feinstein, F.; Gascón, D.; Glicenstein, J.-F.; Guilloux, F.; Nayman, P.; Rarbi, F.; Sanuy, A.; Tavernet, J.-P.; Toussenel, F.; Vincent, P.; Vorobiov, S.

    2012-12-01

    The international CTA consortium has recently entered into its preparatory phase towards the construction of the next-generation Cherenkov Telescope Array CTA. This experiment will be a successor, and based on the return of experience from the three major current-generation arrays H.E.S.S., MAGIC and VERITAS, and aims to significantly improve upon the sensitivity as well as the energy range of its highly successful predecessors. Construction is planned to begin by 2013, and when finished, CTA will be able to explore the highest-energy gamma ray sky in unprecedented detail. To achieve this increase in sensitivity and energy range, CTA will employ the order of 100 telescopes of three different sizes on two sites, with around 1000-4000 channels per camera, depending on the telescope size. To equip and reliably operate the order of 100000 channels of photodetectors (compared to 6000 of the H.E.S.S. array), a new kind of flexible and powerful yet inexpensive front-end hardware will be required. One possible solution is pursued by the NECTAr (New Electronics for the Cherenkov Telescope Array) project. Its main feature is the integration of as much as possible of the front-end electronics (amplifiers, fast analogue samplers, memory and ADCs) into a single ASIC, which will allow very fast readout performances while significantly reducing the cost and the power consumption per channel. Also included is a low-cost FPGA for digital treatment and online data processing, as well as an Ethernet connection. Other priorities of NECTAr are the modularity of the system, a high degree of flexibility in the trigger system as well as the possibility of flexible readout modes to optimise the signal-to-noise ratio while at the same time allowing a significant reduction of data rates, both of which could improve the sensitivity of CTA compared to current detection systems. This paper gives an overview over the development work for the Nectar system, with particular focus on its main

  12. Flight performance of BESS PolarII Aerogel Cherenkov Counter

    NASA Astrophysics Data System (ADS)

    Sakai, Kenichi

    The second scientific flight of the BESS-Polar experiment was performed in December 2007. The objective is understanding elementary particle phenomena in the early universe and propagation mechanism in the Galaxy through a search for antiparticles and antimatter in the cosmic radiation and mesurement of cosmic-ray nuclei. The BESS-Polar II scientific balloon was launched from Williams Field near the US McMurdo station in Antarctica and recorded more than 46x108 cosmic-ray events dualing a scientific balloon flight of 24.5 days. In addition to secondly production, there could be other, more exotic antiproton sources such as the evapolation of primordial black holes . Since the secondly antiproton spectrum has a sharp peak around 2 GeV, antiproton contributions well above or below this peak from other sources could cause an apparent flattening of the spectrum. For clear indentification of antiprotons against electron and muon background around the 0.2GeV 3.0GeV region, a threshold-type aerogel cherenkov counter(ACC) had been adopted. However, its performance was not high enough in the Polar I flight. The number of photoelectrons (N.pe.) was only 6 and the rejection power was 600 against more than 103 times electron and muon background. In BESS-Polar II which aims at precision measurement by vast statistics, the ACC was thoroughly redesigned to increase its rejection power while maintaining low systematic error. Improvements are described below. 1.Changing the aerogel refractive index(1.02 to 1.03): Because the focus of BESS-Polar II was on particle identification in lower energy region, the index was changed and this produced an improvement of 1.5 times N.pe. 2.Redesign of ACC Box Optimization of ACC optical geometry using Monte-Carlo simulation tuned with beam-test data gave 1.2 times N.pe. 3.Changing Aerogel block size (100x100x10mm3 to 190x280x20mm3 ) Larger aerogel blocks were adopted to reduce the inefficient area and N.pe. grew 1.1times. As a result of these

  13. Auxiliary instruments for the absolute calibration of the ASTRI SST-2M prototype for the Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    Maccarone, Maria C.; Segreto, Alberto; Catalano, Osvaldo; La Rosa, Giovanni; Russo, Francesco; Sottile, Giuseppe; Gargano, Carmelo; Biondo, Benedetto; Fiorini, Mauro; Incorvaia, Salvatore; Toso, Giorgio

    2014-08-01

    ASTRI SST-2M is the end-to-end prototype telescope under development by the Italian National Institute of Astrophysics, INAF, proposed for the investigation of the highest-energy gamma-ray band in the framework of the Cherenkov Telescope Array, CTA. The ASTRI SST-2M prototype will be installed in Italy at the INAF station located at Serra La Nave on Mount Etna during Fall 2014. The calibration and scientific validation phase will start soon after. The calibration of a Cherenkov telescope includes several items and tools. The ASTRI SST- 2M camera is equipped with an internal fiber illumination system that allows to perform the relative calibration through monitoring of gain and efficiency variations of each pixel. The absolute calibration of the overall system, including optics, will take advantage from auxiliary instrumentation, namely UVscope and UVSiPM, two small-aperture multi-pixels photon detectors NIST calibrated in lab. During commissioning phase, to measure the main features of ASTRI SST-2M, as its overall spectral response, the main telescope and the auxiliary UVscope-UVSiPM will be illuminated simultaneously by a spatially uniform flux generated by a ground-based light source, named Illuminator, placed at a distance of few hundreds meters. Periodically, during clear nights, the flux profiles of a reference star tracked simultaneously by ASTRI SST-2M and UVscope-UVSiPM will allow to evaluate the total atmospheric attenuation and the absolute calibration constant of the ASTRI SST-2M prototype. In this contribution we describe the auxiliary UVscope-UVSiPM and Illuminator sub-system together with an overview of the end-to-end calibration procedure foreseen for the ASTRI SST-2M telescope prototype.

  14. The Alignment System for a Medium-Sized Schwarzschild-Couder Telescope Prototype for the Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    Ribeiro, Deivid; Humensky, Brian; Nieto, Daniel; V Vassiliev Group in UCLA division of Astronomy and Astrophysics, P Kaaret Group at Iowa University Department of Physics and Astronomy, CTA Consortium

    2016-01-01

    The Cherenkov Telescope Array (CTA) is an international project for a next-generation ground-based gamma-ray observatory. CTA, conceived as an array of tens of imaging atmospheric Cherenkov telescopes, comprising small, medium and large-size telescopes, is aiming to improve on the sensitivity of current-generation experiments by an order of magnitude and provide energy coverage from 20 GeV to more than 300 TeV. The Schwarzschild-Couder design is a candidate 9-m diameter medium-sized telescope featuring a novel aplanatic two-mirror optical design capable of a wide field of view with significantly improved imaging resolution as compared to the traditional Davies-Cotton optical design. Achieving this imaging resolution imposes strict mirror alignment requirements that necessitate a sophisticated alignment system. This system uses a collection of position sensors between panels to determine the relative position of adjacent panels; each panel is mounted on a Stewart platform to allow motion control with six degrees of freedom, facilitating the alignment of the optical surface for the segmented primary and secondary mirrors. Alignments of the primary and secondary mirrors and the camera focal plane with respect to each other are performed utilizing a set of CCD cameras which image LEDs placed on the mirror panels to measure relative translation, and custom-built auto-collimators to measure relative tilt between the primary and secondary mirrors along the optical axis of the telescope. In this contribution we present the status of the development of the SC optical alignment system, soon to be materialized in a full-scale prototype SC medium-size telescope (pSCT) at the Fred Lawrence Whipple Observatory in southern Arizona.

  15. Sensitivity of depth of maximum and absorption depth of EAS to hadron production mechanism

    NASA Technical Reports Server (NTRS)

    Antonov, R. A.; Ivanenko, I. P.; Kanevsky, B. L.; Kuzmin, V. A.; Galkin, V. I.; Hein, L. A.

    1985-01-01

    Comparison of experimental data on depth of extensive air showers (EAS) development maximum in the atmosphere, T sub M and path of absorption, lambda, in the lower atmosphere of EAS with fixed particle number in the energy region eV with the results of calculation show that these parameters are sensitive mainly to the inelastic interaction cross section and scaling violation in the fragmentation and pionization region. The data are explained in a unified manner within the framework of a model in which scaling is violated slightly in the fragmentation region and strongly in the pionization region at primary cosmic rays composition close to the normal one and a permanent increase of inelastic interaction cross section. It is shown that, while interpreting the experimental data, disregard of two methodical points causes a systematic shift in T sub M: (1) shower selection system; and (2) EAS electron lateral distribution when performing the calculations on basis of which the transfer is made from the Cerenkov pulse FWHM to the depth of shower maximum, T sub M.

  16. SU-E-I-87: Calibrating Cherenkov Emission to Match Superficial Dose in Tissue

    SciTech Connect

    Zhang, R; Pogue, B; Glaser, A; Gladstone, D

    2015-06-15

    Purpose: Through Monte Carlo simulations and phantom studies, the dominant factors affecting the calibration of superficial Cherenkov intensity to absolute surface dose was investigated, including tissue optical properties, curvatures, beam properties and imaging angle. Methods: The phasespace files for the TrueBeam system from Varian were used in GAMOS (a GEANT4 based Monte Carlo simulation toolkit) to simulate surface emission Cherenkov signals and the correlated deposited dose. The parameters examined were: i) different tissue optical properties (skin color from light to dark), ii) beam types (X-ray and electron beam), iii) beam energies, iv) thickness of tissues (2.5 cm to 20 cm), v) SSD (80 cm to 120 cm), vi) field sizes (0.5×0.5 cm2 to 20×20 cm2), vii) entrance/exit sides, viii) curvatures (cylinders with diameters from 2.5 cm to 20cm) and ix) imaging angles (0 to 90 degrees). In a specific case, for any Cherenkov photon emitted from the surface, the original position and direction, final position and direction and energy were recorded. Similar experimental measurements were taken in a range of the most pertinent parameters using tissue phantoms. Results: Combining the dose distribution and sampling sensitivity of Cherenkov emission, quantitatively accurate calibration factors (the amount of radiation dose represented by a single Cherenkov photon) were calculated. The data showed relatively large dependence upon different optical properties, curvature, entrance/exit and beam types. For a diffusive surface, the calibration factor was insensitive to imaging angles smaller than 60 degrees. Normalization with the reflectance image was experimentally validated as a simple and accurate method for calibrations of different optical properties. Conclusion: This study sheds light on how and to what extent different conditions affect the calibration from Cherenkov intensity to absolute superficial dose and provides practical solutions to allow quantitative Cherenkov

  17. Gadolinium Doped Water Cherenkov Detector for use as Neutron Detector

    NASA Astrophysics Data System (ADS)

    Davis, Patrick; Woltman, Brian; Mei, Dongming; Sun, Yongchen; Thomas, Keenan; Perevozchikov, Oleg

    2010-11-01

    Background characterization is imperative to the success of rare event physics research such as neutrinoless double-beta decay and dark matter searches. There are a number of different ways to measure backgrounds from muon-induced processes and other forms of high energy events. In our current research, we are constructing a research and development project for the feasibility of a Gadolinium doped water Cherenkov detector as a neutron detector. We are constructing a 46 liter acrylic housing for the Gd-doped water consisting of two acrylic cone sections connected to a middle acrylic cylinder to increase volume while still using 5 inch photo multiplier tubes (PMTs) on either end. I will present the challenges of a Gd-doped water detector and the reasons why our design should be much more successful than past metal housed detectors. I will also discuss our current progress and future goals of our detector including its use in characterizing the background in the future underground laboratory in the Sanford Lab, soon to be DUSEL.

  18. Time-domain measurement of broadband coherent Cherenkov radiation

    SciTech Connect

    Miocinovic, P.; Gorham, P. W.; Guillian, E.; Milincic, R.; Field, R. C.; Walz, D.; Saltzberg, D.; Williams, D.

    2006-08-15

    We report on further analysis of coherent microwave Cherenkov impulses emitted via the Askaryan mechanism from high-energy electromagnetic showers produced at the Stanford Linear Accelerator Center (SLAC). In this report, the time-domain based analysis of the measurements made with a broadband (nominally 1-18 GHz) log periodic dipole array antenna is described. The theory of a transmit-receive antenna system based on time-dependent effective height operator is summarized and applied to fully characterize the measurement antenna system and to reconstruct the electric field induced via the Askaryan process. The observed radiation intensity and phase as functions of frequency were found to agree with expectations from 0.75-11.5 GHz within experimental errors on the normalized electric field magnitude and the relative phase; {sigma}{sub RvertcalbarEverticalbar}=0.039 {mu}V/MHz/TeV and {sigma}{sub {phi}}=17 deg. This is the first time this agreement has been observed over such a broad bandwidth, and the first measurement of the relative phase variation of an Askaryan pulse. The importance of validation of the Askaryan mechanism is significant since it is viewed as the most promising way to detect cosmogenic neutrino fluxes at E{sub {nu}}(greater-or-similar sign)10{sup 15} eV.

  19. Cherenkov radiation with massive, C P T -violating photons

    NASA Astrophysics Data System (ADS)

    Colladay, Don; McDonald, Patrick; Potting, Robertus

    2016-06-01

    The source of C P T violation in the photon sector of the Standard Model Extension arises from a Chern-Simons-like contribution that involves a coupling to a fixed background vector field kAF μ . These Lorentz- and C P T -violating photons have well-known theoretical issues that arise from missing states at low momenta when kAF μ is timelike. In order to make the theory consistent, a tiny mass for the photon can be introduced, well below current experimental bounds. The implementation of canonical quantization can then be implemented as in the C P T -preserving case by using the Stückelberg mechanism. We explicitly construct a covariant basis of properly normalized polarization vectors at fixed three-momentum satisfying the momentum space field equations, in terms of which the vector field can be expanded. As an application of the theory, we calculate the Cherenkov radiation rate for the case of purely timelike kAF μ and find a radiation rate at high energies that has a contribution that does not depend on the mass used to regulate the photons.

  20. Time-Domain Measurement of Broadband Coherent Cherenkov Radiation

    SciTech Connect

    Miocinovic, P.; Field, R.C.; Gorham, P.W.; Guillian, E.; Milincic, R.; Saltzberg, D.; Walz, D.; Williams, D.; /UCLA

    2006-03-13

    We report on further analysis of coherent microwave Cherenkov impulses emitted via the Askaryan mechanism from high-energy electromagnetic showers produced at the Stanford Linear Accelerator Center (SLAC). In this report, the time-domain based analysis of the measurements made with a broadband (nominally 1-18 GHz) log periodic dipole antenna (LPDA) is described. The theory of a transmit-receive antenna system based on time-dependent effective height operator is summarized and applied to fully characterize the measurement antenna system and to reconstruct the electric field induced via the Askaryan process. The observed radiation intensity and phase as functions of frequency were found to agree with expectations from 0.75-11.5 GHz within experimental errors on the normalized electric field magnitude and the relative phase; {sigma}{sub R|E|} = 0.039 {micro}V/MHz/TeV and {sigma}{sub {phi}} = 17{sup o}. This is the first time this agreement has been observed over such a broad bandwidth, and the first measurement of the relative phase variation of an Askaryan pulse. The importance of validation of the Askaryan mechanism is significant since it is viewed as the most promising way to detect cosmogenic neutrino fluxes at E{sub v} {ge} 10{sup 15} eV.

  1. Charged Kaon Mass Measurement using the Cherenkov Effect

    SciTech Connect

    Graf, N.; Lebedev, A.; Abrams, R.J.; Akgun, U.; Aydin, G.; Baker, W.; Barnes, P.D., Jr.; Bergfeld, T.; Beverly, L.; Bujak, A.; Carey, D.; /Fermilab /Virginia U. /Iowa U.

    2009-09-01

    The two most recent and precise measurements of the charged kaon mass use X-rays from kaonic atoms and report uncertainties of 14 ppm and 22 ppm yet differ from each other by 122 ppm. We describe the possibility of an independent mass measurement using the measurement of Cherenkov light from a narrow-band beam of kaons, pions, and protons. This technique was demonstrated using data taken opportunistically by the Main Injector Particle Production experiment at Fermi National Accelerator Laboratory which recorded beams of protons, kaons, and pions ranging in momentum from +37 GeV/c to +63 GeV/c. The measured value is 491.3 {+-} 1.7 MeV/c{sup 2}, which is within 1.4{sigma} of the world average. An improvement of two orders of magnitude in precision would make this technique useful for resolving the ambiguity in the X-ray data and may be achievable in a dedicated experiment.

  2. Latest news from the High Altitude Water Cherenkov Observatory

    NASA Astrophysics Data System (ADS)

    González Muñoz, A.; HAWC Collaboration

    2016-07-01

    The High Altitude Water Cherenkov Observatory is an air shower detector designed to study very-high-energy gamma rays (∼ 100 GeV to ∼ 100 TeV). It is located in the Pico de Orizaba National Park, Mexico, at an elevation of 4100 m. HAWC started operations since August 2013 with 111 tanks and in April of 2015 the 300 tanks array was completed. HAWC's unique capabilities, with a field of view of ∼ 2 sr and a high duty cycle of 5%, allow it to survey 2/3 of the sky every day. These features makes HAWC an excellent instrument for searching new TeV sources and for the detection of transient events, like gamma-ray bursts. Moreover, HAWC provides almost continuous monitoring of already known sources with variable gamma-ray fluxes in most of the northern and part of the southern sky. These observations will bring new information about the acceleration processes that take place in astrophysical environments. In this contribution, some of the latest scientific results of the observatory will be presented.

  3. The Age Parameter in Giant EAS

    NASA Astrophysics Data System (ADS)

    Capdevielle, J. N.; Cohen, F.; Sanosyan, K.

    The age parameter from the longitudinal development can be used to describe the lateral distribution in giant EAS up to 5 km from the axis, even if the scaling properties of Approximation B in cascade theory fail after 3.5 Moliere radii. A set of analytic descriptions is proposed under the gaussian hypergeometric formalism replacing the Eulerian formalism of the classical NKG distribution, valid for electrons, muons and vertical equivalent muons (v.e.m.).

  4. NICHE: Using Cherenkov radiation to extend Telescope Array to sub-PeV energies

    NASA Astrophysics Data System (ADS)

    Bergman, Douglas; Krizmanic, John; Tsunesada, Yoshiki; Abu-Zayyad, Tareq; Belz, John; Thomson, Gordon

    2016-03-01

    The Non-Imaging CHErenkov (NICHE) Array will measure the flux and nuclear composition evolution of cosmic rays (CRs) from below 1 PeV to 1 EeV. NICHE will be co-sited with the Telescope Array (TA) Low Energy (TALE) extension, and will observe events simultaneously with the TALE telescopes acting in imaging-Cherenkov mode. This will be the first hybrid-Cherenkov (simultaneous imaging and non-imaging Cherenkov) measurements of CRs in the Knee region of the CR energy spectrum. NICHE uses easily deployable detectors to measure the amplitude and time-spread of the air-shower Cherenkov signal to achieve an event-by-event measurement of Xmax and energy, each with excellent resolution. First generation detectors are under construction and will form an initial prototype array (j-NICHE) that will be deployed in Summer 2016. In this talk, the NICHE design, array performance, prototype development, and status will be discussed as well as NICHE's ability to measure the cosmic ray nuclear composition as a function of energy.

  5. Cherenkov and scintillation light separation on the TheiaR &D experiment

    NASA Astrophysics Data System (ADS)

    Caravaca, Javier; Land, Benjamin

    2016-03-01

    Identifying by separate the scintillation and Cherenkov light produced in a scintillation medium enables outstanding capabilities for future particle detectors, being the most relevant: allowing particle directionality information in a low energy threshold detector and improved particle identification. The TheiaR &D experiment uses an array of small and fast photomultipliers (PMTs) and state-of-the-art electronics to demonstrate the reconstruction of a Cherenkov ring in a scintillation medium, based on the number of produced photoelectrons and the timing information. A charged particle ionizing a scintillation medium produces a prompt Cherenkov cone and late isotropic scintillation light, typically delayed by <1ns. The fast response of our PMTs and DAQ provides a precision well below the ns level, making possible the time separation. Furthermore, the usage of the new developed water-based liquid scintillators (WBLS) provides a medium with a tunable Cherenkov/Scintillation light yield ratio, enhancing the visibility of the dimer Cherenkov light in presence of the scintillation light. Description of the experiment, details of the analysis and preliminary results of the first months of running will be discussed.

  6. Pulsars at the Highest Energies: Questions for AGILE, Fermi (GLAST) and Atmospheric Cherenkov Telescopes

    NASA Astrophysics Data System (ADS)

    Thompson, D. J.

    2008-12-01

    Observational studies of gamma-ray pulsars have languished in recent years, while theoretical studies have made significant strides. Now, with new and improved gamma-ray telescopes coming online, opportunities present themselves for dramatic improvements in our understanding of these objects. The new facilities and better modeling of processes at work in high-energy pulsars will address a number of important open questions.

  7. Pulsars at the Highest Energies: Questions for AGILE, Fermi (GLAST) and Atmospheric Cherenkov Telescopes

    NASA Technical Reports Server (NTRS)

    Thompson, D.J.

    2008-01-01

    Observational studies of gamma-ray pulsars languished in recent years, while theoretical studies made significant strides. Now, with new and improved gamma-ray telescopes coming online, opportunities present themselves for dramatic improvements in our understanding of these objects. The new facilities and better modeling of processes at work in high-energy pulsars should address a number of important open questions, some of which are summarized.

  8. Physically associated companion of E+A Galaxies - III

    NASA Astrophysics Data System (ADS)

    Yamauchi, Chisato; Goto, Tomotsugu; Yagi, Masafumi

    2007-02-01

    The subject of this proposal is to identify physically associated companions of E+A galaxies, and to obtain basic spectroscopic features of bright companions in order to understand the evolution of E+A system. E+A galaxies have been understood as post-starburst galaxies based on their strong Balmer absorption lines and the absence of [OII] or H(alpha) emission lines. Their origin has remained unknown for more than 20 years since E+A galaxies are very rare. To rectify the situation, Goto (2003,2005) has selected large & uniform E+A sample using the Sloan Digital Sky Survey (SDSS) data. Goto (2003) found that there is an excess in number of accompanying galaxies of E+As in the SDSS imaging data, and suggest that the origin of E+As is dynamical merger/interaction with companion galaxies. The merger/interaction origin scenario also implies that E+As can be progenitors of early-type galaxies and play important roles in galaxy evolution. The discussion of Goto (2003) was based on the imaging data. The accompanying galaxies are not spectroscopically observed in the SDSS, and therefore it is unknown which galaxy is a real companion of E+A. We therefore propose spectroscopic observation to identify physically associated companions, and to construct a companion catalog without any contamination of fore/background overlapping galaxies. The correlation between properties of E+A and those of companions would give us great hints for understanding the evolution of the E+A system, and set constraints on the theoretical models of the E+A formation.

  9. Phyiscal associated companion of E+A Galaxies

    NASA Astrophysics Data System (ADS)

    Yamauchi, Chisato; Goto, Tomotsugu; Yagi, Masafumi

    2005-08-01

    The subject of this proposal is to identify physically associated companions of E+A galaxies, and to obtain basic spectroscopic features of bright companions in order to understand the evolution of E+A system. E+A galaxies have been understood as post-starburst galaxies based on their strong Balmer absorption lines and the absence of [OII] or H(alpha) emission lines. Their origin has remained unknown for more than 20 years since E+A galaxies are very rare. To rectify the situation, Goto (2003,2005) has selected large & uniform E+A sample using the Sloan Digital Sky Survey (SDSS) data. Goto (2003) found that there is an excess in number of accompanying galaxies of E+As in the SDSS imaging data, and suggest that the origin of E+As is dynamical merger/interaction with companion galaxies. The merger/interaction origin scenario also implies that E+As can be progenitors of early-type galaxies and play important roles in galaxy evolution. The discussion of Goto (2003) was based on the imaging data. The accompanying galaxies are not spectroscopically observed in SDSS, and it is unknown which galaxy is the real companion of E+A. We therefore propose spectroscopic observation to identify physically associated companions, and to construct companion catalog without any contamination of fore/background overlapping galaxies. The correlation between properties of E+A and those of companions would give us great hints for understanding the evolution of E+A system, and set constraints on the theoretical models of E+A formation.

  10. The Environment of ``E+A'' Galaxies

    NASA Astrophysics Data System (ADS)

    Zabludoff, Ann I.; Zaritsky, Dennis; Lin, Huan; Tucker, Douglas; Hashimoto, Yasuhiro; Shectman, Stephen A.; Oemler, Augustus; Kirshner, Robert P.

    1996-07-01

    The spectrum of an "E + A" galaxy (Dressier & Gunn) which is dominated by a young stellar component but lacks the emission lines characteristic of any significant, on-going star formation suggests that the galaxy experienced a brief, powerful starburst within the last gigayear (Dressler & Gunn; Couch & Sharples). In past work, this violent star formation history and the detection of these galaxies almost exclusively in distant clusters linked them to the Butcher-Oemler (B-O) effect (Butcher & Oemler) and argued for the influence of cluster environment in the evolution of galaxies. However, no statistical survey of the environments of "E+A"s had ever been made. From 11,113 galaxy spectra in the Las Campanas Redshift Survey (Shectman and coworkers), we have obtained a unique and well-defined sample of 21 nearby "E+A" galaxies with the same spectral characteristics as "E+A"s in distant clusters. These "E+A"s are selected to have the strongest Balmer absorption lines (the average of the equivalent widths of Hβ, γ, δ is >5.5 A) and weakest [O II] emission-line equivalent widths (<2.5 A, which corresponds to a detection of [O II] of less than 2 σ significance) of any of the galaxies in the survey. In contrast to inferences drawn from previous studies, we find that a large fraction (75%) of nearby "E + A "s lie in the field, well outside of clusters and rich groups of galaxies. We conclude that interactions with the cluster environment, in the form of the intracluster medium or cluster potential, are not essential for "E+A" formation and therefore that the presence of these galaxies in distant clusters does not provide strong evidence for the effects of cluster environment on galaxy evolution. If one mechanism is responsible for "E+A" formation, then the observations that "E+A"s exist in the field and that at least five of the 21 in our sample have clear tidal features argue that galaxy-galaxy interactions and mergers are that mechanism. The most likely environments

  11. SNM Detection with an Optimized Water Cherenkov Neutron Detector

    SciTech Connect

    Dazeley, S.; Sweany, M.; Bernstein, A.

    2012-07-23

    Special Nuclear Material (SNM) can either spontaneously fission or be induced to do so: either case results in neutron emission. For this reason, neutron detection performs a crucial role in the functionality of Radiation Portal Monitoring (RPM) devices. Since neutrons are highly penetrating and difficult to shield, they could potentially be detected escaping even a well-shielded cargo container. If the shielding were sophisticated, detecting escaping neutrons would require a highly efficient detector with close to full solid angle coverage. In 2008, we reported the successful detection of neutrons with a 250 liter (l) gadolinium doped water Cherenkov prototype—a technology that could potentially be employed cost effectively with full solid angle coverage. More recently we have built and tested both 1-kl and 3.5-kl versions, demonstrating that very large, cost effective, non-flammable and environmentally benign neutron detectors can be operated efficiently without being overwhelmed by background. In our paper, we present a new design for a modular system of water-based neutron detectors that could be deployed as a real RPM. The modules contain a number of optimizations that have not previously been combined within a single system. We present simulations of the new system, based on the performance of our previous detectors. These simulations indicate that an optimized system such as is presented here could achieve SNM sensitivity competitive with a large 3He-based system. Moreover, the realization of large, cost effective neutron detectors could, for the first time, enable the detection of multiple neutrons per fission from within a large object such as a cargo container. Such a signal would provide a robust indication of the presence of fissioning material, reducing the frequency of false alarms while increasing sensitivity.

  12. SNM Detection with an Optimized Water Cherenkov Neutron Detector

    DOE PAGESBeta

    Dazeley, S.; Sweany, M.; Bernstein, A.

    2012-07-23

    Special Nuclear Material (SNM) can either spontaneously fission or be induced to do so: either case results in neutron emission. For this reason, neutron detection performs a crucial role in the functionality of Radiation Portal Monitoring (RPM) devices. Since neutrons are highly penetrating and difficult to shield, they could potentially be detected escaping even a well-shielded cargo container. If the shielding were sophisticated, detecting escaping neutrons would require a highly efficient detector with close to full solid angle coverage. In 2008, we reported the successful detection of neutrons with a 250 liter (l) gadolinium doped water Cherenkov prototype—a technology thatmore » could potentially be employed cost effectively with full solid angle coverage. More recently we have built and tested both 1-kl and 3.5-kl versions, demonstrating that very large, cost effective, non-flammable and environmentally benign neutron detectors can be operated efficiently without being overwhelmed by background. In our paper, we present a new design for a modular system of water-based neutron detectors that could be deployed as a real RPM. The modules contain a number of optimizations that have not previously been combined within a single system. We present simulations of the new system, based on the performance of our previous detectors. These simulations indicate that an optimized system such as is presented here could achieve SNM sensitivity competitive with a large 3He-based system. Moreover, the realization of large, cost effective neutron detectors could, for the first time, enable the detection of multiple neutrons per fission from within a large object such as a cargo container. Such a signal would provide a robust indication of the presence of fissioning material, reducing the frequency of false alarms while increasing sensitivity.« less

  13. Results on the Performance of a Broad Band Focussing Cherenkov Counter

    DOE R&D Accomplishments Database

    Cester, R.; Fitch, V. L.; Montag, A.; Sherman, S.; Webb, R. C.; Witherell, M. S.

    1980-01-01

    The field of ring imaging (broad band differential) Cherenkov detectors has become a very active area of interest in detector development at several high energy physics laboratories. Our group has previously reported on a method of Cherenkov ring imaging for a counter with large momentum and angular acceptance using standard photo multipliers. Recently, we have applied this technique to the design of a set of Cherenkov counters for use in a particle search experiment at Fermi National Accelerator Laboratory (FNAL). This new detector operates over the range 0.998 < ..beta.. < 1.000 in velocity with a delta..beta.. approx. 2 x 10{sup -4}. The acceptance in angle is +- 14 mrad in the horizontal and +- 28 mrad in the vertical. We report here on the performance of this counter.

  14. The Cherenkov Telescope Array: An observatory for Ground-based High Energy Gamma Ray Astronomy.

    NASA Astrophysics Data System (ADS)

    Medina, M. C.; CTA Consortium

    Over the past 15 years; Very High Energy (VHE) -ray experiments as H.E.S.S.; MAGIC and VERITAS have been very successful unveiling the mysteries of the non-thermal Universe using Cherenkov telescopes based on Earth. The next step in the evolution of the -ray Astronomy is to gather their efforts to build a global and innovative ground based facility: the Cherenkov Telescope Array (CTA). This is being conceived as an array of Cherenkov telescopes working as an open observatory; covering a wide energy range; with an enhanced sensitivity and improved spatial; temporal and energy resolution. The project is at the end of its Preparatory Phase. The decision on its location is about to be taken and the construction is expected to begin in 2015. In this article; we briefly describe the general status of the project and the Argentinian participation.

  15. Controlled steering of Cherenkov surface plasmon wakes with a one-dimensional metamaterial.

    PubMed

    Genevet, Patrice; Wintz, Daniel; Ambrosio, Antonio; She, Alan; Blanchard, Romain; Capasso, Federico

    2015-09-01

    In the Cherenkov effect a charged particle moving with a velocity faster than the phase velocity of light in the medium radiates light that forms a cone with a half angle determined by the ratio of the two speeds. Here, we show that by creating a running wave of polarization along a one-dimensional metallic nanostructure consisting of subwavelength-spaced rotated apertures that propagates faster than the surface plasmon polariton phase velocity, we can generate surface plasmon wakes, a two-dimensional analogue of Cherenkov radiation. The running wave of polarization travels with a speed determined by the angle of incidence and the photon spin angular momentum of the incident radiation. By changing either one of these properties we demonstrate controlled steering of the Cherenkov surface plasmon wakes. PMID:26149237

  16. Reversed Cherenkov-Transition Radiation by a Charge Crossing a Left-Handed Medium Boundary

    SciTech Connect

    Galyamin, Sergey N.; Tyukhtin, Andrey V.; Kanareykin, Alexey; Schoessow, Paul

    2009-11-06

    We analyze the radiation from a charged particle crossing the boundary between an ordinary medium and a 'left-handed' metamaterial. We obtain exact and approximate expressions for the field components and develop algorithms for their computation. The spatial radiation in this system can be separated into three distinct components, corresponding to ordinary transition radiation having a relatively large magnitude, Cherenkov radiation, and reversed Cherenkov-transition radiation (RCTR). The last one is explained by reflection and refraction of reversed Cherenkov radiation at the interface. Conditions for generating of RCTR are obtained. We note properties of this radiation that have potential applications in the detection of charged particles and accelerator beams and for the characterization of metamaterial macroscopic parameters (epsilon, mu).

  17. SYNCHROTRON EMISSION DRIVEN BY THE CHERENKOV-DRIFT INSTABILITY IN ACTIVE GALACTIC NUCLEI

    SciTech Connect

    Osmanov, Z.; Chkheidze, N.

    2013-02-10

    In the present paper, we study the generation of synchrotron emission by means of the feedback of Cherenkov-drift waves on the particle distribution through the diffusion process. Despite the efficient synchrotron losses, it is demonstrated that the excited Cherenkov-drift instability leads to the quasi-linear diffusion (QLD), the effect of which is balanced by dissipation factors and, as a result, the pitch angles are prevented from damping, thus maintaining the corresponding synchrotron emission. We analyze the model for a wide range of physical parameters and determine that the mechanism of QLD guarantees the generation of electromagnetic radiation from soft X-rays up to soft {gamma}-rays, which is strongly correlated with Cherenkov-drift emission ranging from IR up to UV energy domains.

  18. Use of Cherenkov-type detectors for measurements of runaway electrons in the ISTTOK tokamak

    SciTech Connect

    Plyusnin, V. V.; Fernandes, H.; Silva, C.; Duarte, P.

    2008-10-15

    Gas, fluid, or solid Cherenkov-type detectors have been widely used in high-energy physics for determination of parameters of charged particles, which are moving with relativistic velocities. This paper presents experimental results on the detection of runaway electrons using Cherenkov-type detectors in the ISTTOK tokamak discharges. Such detectors have been specially designed for measurements of energetic electrons in tokamak plasma. The technique based on the use of the Cherenkov-type detectors has enabled the detection of energetic electrons (energies higher than 80 keV) and determination of their spatial and temporal parameters in the ISTTOK discharges. Obtained experimental data were found in adequate agreement to the results of numerical modeling of the runaway electron generation in ISTTOK.

  19. Distributed beam loss monitor based on the Cherenkov effect in an optical fiber

    NASA Astrophysics Data System (ADS)

    Maltseva, Yu; Emanov, F. A.; Petrenko, A. V.; Prisekin, V. G.

    2015-05-01

    This review discusses a distributed beam loss monitor which is based on the Cherenkov effect in an optical fiber and which has been installed at the VEPP-5 Injection Complex at the Budker Institute of Nuclear Physics. The principle of the device operation consists in detecting the Cherenkov radiation generated in an optical fiber by relativistic charged particles that are produced in an electromagnetic shower when highly relativistic beam particles (electrons or positrons) hit the accelerator vacuum chamber wall. Our experiments used a photomultiplier tube (PMT) to detect the Cherenkov light. Knowing when the PMT signal arrives tells us where the beam loss occurs. Using a 20-m-long optical fiber allowed a detector spatial resolution of 3 m. The way to improve the resolution is to optimize the monitor working conditions and optical fiber and PMT parameters, potentially leading to a resolution of as fine as 0.5 m according to our estimates.

  20. Underground Prototype Water Cherenkov Muon Detector with the Tibet Air Shower Array

    SciTech Connect

    Amenomori, M.; Nanjo, H.; Bi, X. J.; Ding, L. K.; Feng, Zhaoyang; He, H. H.; Hu, H. B.; Lu, H.; Lu, S. L.; Ren, J. R.; Tan, Y. H.; Wang, B.; Wang, H.; Wang, Y.; Wu, H. R.; Zhang, H. M.; Zhang, J. L.; Zhang, Y.; Chen, D.; Kawata, K.

    2008-12-24

    We are planning to build a 10,000 m{sup 2} water-Cherenkov-type muon detector (MD) array under the Tibet air shower (AS) array. The Tibet AS+MD array will have the sensitivity to detect gamma rays in the 100 TeV region by an order of the magnitude better than any other previous existing detectors in the world. In the late fall of 2007, a prototype water Cherenkov muon detector of approximately 100 m{sup 2} was constructed under the existing Tibet AS array. The preliminary data analysis is in good agreement with our MC simulation. We are now ready for further expanding the underground water Cherenkov muon detector.

  1. Quantum calculation of the Vavilov-Cherenkov radiation by twisted electrons

    NASA Astrophysics Data System (ADS)

    Ivanov, I. P.; Serbo, V. G.; Zaytsev, V. A.

    2016-05-01

    We present a detailed quantum electrodynamical description of Vavilov-Cherenkov radiation emitted by a relativistic twisted electron in the transparent medium. Simple expressions for the spectral and spectral-angular distributions as well as for the polarization properties of the emitted radiation are obtained. Unlike the plane-wave case, the twisted electron produces radiation within the annular angular region, with enhancement towards its boundaries. Additionally, the emitted photons can have linear polarization not only in the scattering plane but also in the orthogonal direction. We find that the Vavilov-Cherenkov radiation emitted by an electron in a superposition of two vortex states exhibits a strong azimuthal asymmetry. Thus, the Vavilov-Cherenkov radiation offers itself as a convenient diagnostic tool of such electrons and complements the traditional microscopic imaging.

  2. Hadron identification at 200 GeV/c using a ring imaging Cherenkov detector

    SciTech Connect

    Coutrakon, G.B.

    1983-01-01

    As the energy of particle beams has continued to increase over the years, there has been a growing need to identify secondary particles with larger energies produced at the target from these beams. Over the last twenty years, much effort has gone into developing detectors which can identify these particles by the Cherenkov effect. The authors present, here, a new technique which uses the Cherenkov effect, but extends the energy range in which particles can be identified beyond currently existing detector systems. The technique involves the localization of ultraviolet photons to 0.5mm accuracy within large photon detection aperatures (approx. = 1 m/sup 2/).

  3. Hadron Identification at 200 Gev/c Using a Ring Imaging Cherenkov Detector.

    NASA Astrophysics Data System (ADS)

    Coutrakon, George Booth

    As the energy of particle beams has continued to increase over the years, there has been a growing need to identify secondary particles with larger energies produced at the target from these beams. Over the last twenty years, much effort has gone into developing detectors which can identify these particles by the Cherenkov effect. We present, here, a new technique which uses the Cherenkov effect, but extends the energy range in which particles can be identified beyond currently existing detector systems. The technique involves the localization of ultraviolet photons to 0.5mm accuracy within large photon detection aperatures ((DBLTURN) 1 m('2)).

  4. Radioassay of dual-labeled samples with a Cherenkov counting technique

    NASA Astrophysics Data System (ADS)

    Fujii, Haruo; Takiue, Makoto

    1998-03-01

    A new Cherenkov counting technique which allows radioactivities of a dual-labeled sample to be determined simultaneously by using a wavelength shifter has been proposed, and tested for the pairs 32P-36Cl and 86Rb-36Cl. The minimum requirements for this method are a single channel liquid scintillation counter, a wavelength shifter and a reference sample for determining the Cherenkov counting efficiency. The simple procedure for sample preparation and measurement makes the technique very useful for routine radioassay with the help of a desk-top computer.

  5. Radioassay of dual-labeled samples with a Cherenkov counting technique

    NASA Astrophysics Data System (ADS)

    Fujii, Haruo; Takiue, Makoto

    1988-03-01

    A new Cherenkov counting technique which allows radioactivities of a dual-labeled sample to be determined simultaneously by using a wavelength shifter has been proposed, and tested for the pairs 32P 36Cl and 86Rb 36Cl. The minimum requirements for this method are a single channel liquid scintillation counter, a wavelength shifter and a reference sample for determining the Cherenkov counting efficiency. The simple procedure for sample preparation and measurement makes the technique very useful for routine radioassay with the help of a desk-top computer.

  6. Cherenkov detectors for spatial imaging applications using discrete-energy photons

    NASA Astrophysics Data System (ADS)

    Rose, Paul B.; Erickson, Anna S.

    2016-08-01

    Cherenkov detectors can offer a significant advantage in spatial imaging applications when excellent timing response, low noise and cross talk, large area coverage, and the ability to operate in magnetic fields are required. We show that an array of Cherenkov detectors with crude energy resolution coupled with monochromatic photons resulting from a low-energy nuclear reaction can be used to produce a sharp image of material while providing large and inexpensive detector coverage. The analysis of the detector response to relative transmission of photons with various energies allows for reconstruction of material's effective atomic number further aiding in high-Z material identification.

  7. Monitor and control systems for the SLD Cherenkov Ring Imaging Detector

    SciTech Connect

    Antilogus, P.; Aston, D.; Bienz, T.; Bird, F.; Dasu, S.; Dunwoodie, W.; Fernandez, F.; Hallewell, G.; Kawahara, H.; Korff, P.; Kwon, Y.; Leith, D.; Muller, D.; Nagamine, T.; Pavel, T.; Rabinowitz, L.; Ratcliff, B.; Rensing, P.; Schultz, D.; Shapiro, S.; Simopoulos, C.; Solodov, E.; Toge, N.; Va'Vra, J.; Williams, S.; Whitaker, J.; Wilson, R.J.; Bean, A.; Caldwell, D.; Duboscq, J.; Huber, J.; Lu, A.; McHugh, S.; Mathys, L.; Morriso

    1989-10-01

    To help ensure the stable long-term operation of a Cherenkov Ring Detector at high efficiency, a comprehensive monitor and control system is being developed. This system will continuously monitor and maintain the correct operating temperatures, and will provide an on-line monitor and maintain the correct operating temperatures, and will provide an on-line monitor of the pressures, flows, mixing, and purity of the various fluids. In addition the velocities and trajectories of Cherenkov photoelectrons drifting within the imaging chambers will be measured using a pulsed uv lamp and a fiberoptic light injection system. 9 refs., 6 figs.

  8. Mixed optical Cherenkov-Bremsstrahlung radiation in vicinity of the Cherenkov cone from relativistic heavy ions: Unusual dependence of the angular distribution width on the radiator thickness

    NASA Astrophysics Data System (ADS)

    Rozhkova, E. I.; Pivovarov, Yu. L.

    2016-07-01

    The Cherenkov radiation (ChR) angular distribution is usually described by the Tamm-Frank (TF) theory, which assumes that relativistic charged particle moves uniformly and rectilinearly in the optically transparent radiator. According to the TF theory, the full width at half maximum (FWHM) of the ChR angular distribution inversely depends on the radiator thickness. In the case of relativistic heavy ions (RHI) a slowing-down in the radiator may sufficiently change the angular distribution of optical radiation in vicinity of the Cherenkov cone, since there appears a mixed ChR-Bremsstrahlung radiation. As a result, there occurs a drastic transformation of the FWHM of optical radiation angular distribution in dependence on the radiator thickness: from inversely proportional (TF theory) to the linearly proportional one. In our paper we present the first analysis of this transformation taking account of the gradual velocity decrease of RHI penetrating through a radiator.

  9. 32 CFR 651.33 - Actions normally requiring an EA.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 32 National Defense 4 2010-07-01 2010-07-01 true Actions normally requiring an EA. 651.33 Section 651.33 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY (CONTINUED) ENVIRONMENTAL QUALITY ENVIRONMENTAL ANALYSIS OF ARMY ACTIONS (AR 200-2) Environmental Assessment § 651.33 Actions normally requiring an EA. The...

  10. 33 CFR 230.10 - Environmental Assessments (EA).

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... determining whether to prepare an EIS or a FONSI (40 CFR 1508.9). The district commander is responsible for... 33 Navigation and Navigable Waters 3 2010-07-01 2010-07-01 false Environmental Assessments (EA..., DEPARTMENT OF DEFENSE PROCEDURES FOR IMPLEMENTING NEPA § 230.10 Environmental Assessments (EA). (a)...

  11. 33 CFR 230.10 - Environmental Assessments (EA).

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... determining whether to prepare an EIS or a FONSI (40 CFR 1508.9). The district commander is responsible for... 33 Navigation and Navigable Waters 3 2014-07-01 2014-07-01 false Environmental Assessments (EA..., DEPARTMENT OF DEFENSE PROCEDURES FOR IMPLEMENTING NEPA § 230.10 Environmental Assessments (EA). (a)...

  12. 32 CFR 651.24 - Supplemental EAs and supplemental EISs.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Supplemental EAs and supplemental EISs. As detailed in § 651.5(g) and in 40 CFR 1502.9(c), proposed actions may... 32 National Defense 4 2011-07-01 2011-07-01 false Supplemental EAs and supplemental EISs. 651.24 Section 651.24 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY...

  13. 32 CFR 651.24 - Supplemental EAs and supplemental EISs.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Supplemental EAs and supplemental EISs. As detailed in § 651.5(g) and in 40 CFR 1502.9(c), proposed actions may... 32 National Defense 4 2014-07-01 2013-07-01 true Supplemental EAs and supplemental EISs. 651.24 Section 651.24 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY...

  14. 32 CFR 651.24 - Supplemental EAs and supplemental EISs.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Supplemental EAs and supplemental EISs. As detailed in § 651.5(g) and in 40 CFR 1502.9(c), proposed actions may... 32 National Defense 4 2010-07-01 2010-07-01 true Supplemental EAs and supplemental EISs. 651.24 Section 651.24 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY...

  15. 77 FR 57565 - EasTrans, LLC; Notice of Filing

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-18

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission EasTrans, LLC; Notice of Filing Take notice that on September 11, 2012, EasTrans, LLC filed to revise its Statement of Operating Conditions to correct, update, and or...

  16. 32 CFR 651.24 - Supplemental EAs and supplemental EISs.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Supplemental EAs and supplemental EISs. As detailed in § 651.5(g) and in 40 CFR 1502.9(c), proposed actions may... 32 National Defense 4 2013-07-01 2013-07-01 false Supplemental EAs and supplemental EISs. 651.24 Section 651.24 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY...

  17. 32 CFR 651.24 - Supplemental EAs and supplemental EISs.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Supplemental EAs and supplemental EISs. As detailed in § 651.5(g) and in 40 CFR 1502.9(c), proposed actions may... 32 National Defense 4 2012-07-01 2011-07-01 true Supplemental EAs and supplemental EISs. 651.24 Section 651.24 National Defense Department of Defense (Continued) DEPARTMENT OF THE ARMY...

  18. 47 CFR 11.61 - Tests of EAS procedures.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... EAS Local Area or State. Analog and digital class D non-commercial educational FM, analog and digital LPFM stations, and analog and digital LPTV stations are required to transmit only the test script. (ii... and digital AM, FM, and TV broadcast stations must conduct tests of the EAS header and EOM codes...

  19. 47 CFR 11.11 - The Emergency Alert System (EAS).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... Broadband Service (EBS) stations; DBS services, as defined in 47 CFR 25.701(a) (including certain Ku-band Fixed-Satellite Service Direct to Home providers); SDARS, as defined in 47 CFR 25.201; participating... herein. At a minimum EAS Participants must use a common EAS protocol, as defined in § 11.31, to send...

  20. 47 CFR 90.904 - Aggregation of EA licenses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Aggregation of EA licenses. 90.904 Section 90.904 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES... Service § 90.904 Aggregation of EA licenses. The Commission will license each Spectrum Block A through...

  1. Draft Genome Sequence of Rice Isolate Pseudomonas chlororaphis EA105

    PubMed Central

    McCully, Lucy M.; Bitzer, Adam S.; Spence, Carla A.; Bais, Harsh P.

    2014-01-01

    Pseudomonas chlororaphis EA105, a strain isolated from rice rhizosphere, has shown antagonistic activities against a rice fungal pathogen, and could be important in defense against rice blast. We report the draft genome sequence of EA105, which is an estimated size of 6.6 Mb. PMID:25540352

  2. Digital FDIRC: A focused differential internal reflection Cherenkov imaged by SiPM arrays

    NASA Astrophysics Data System (ADS)

    Marrocchesi, P. S.; Bagliesi, M. G.; Basti, A.; Bigongiari, G.; Bonechi, S.; Brogi, P.; Checchia, C.; Collazuol, G.; Maestro, P.; Morsani, F.; Piemonte, C.; Stolzi, F.; Suh, J. E.; Sulaj, A.

    2016-07-01

    A prototype of an Internal Reflection Cherenkov, equipped with a SiO2 (fused silica) radiator bar optically connected to a cylindrical mirror, was tested at CERN SPS in March 2015 with a beam of relativistic ions obtained from fragmentation of primary argon nuclei at energies 13, 19 and 30 GeV/n. The detector, designed to identify cosmic nuclei, features an imaging focal plane of dimensions ~ 4 cm × 3 cm equipped with 16 arrays of NUV-SiPM (near-ultraviolet sensitive silicon photon avalanche detector) for a total of 1024 sensitive elements. The outstanding performance of the photodetectors (with negligible background in between adjacent photopeaks) allowed us to apply the technique of photon counting to the Cherenkov light collected on the focal plane. Thanks to the fine granularity of the array elements, the Cherenkov pattern was recorded together with the total number of detected photoelectrons increasing as Z2 as a function of the atomic number Z. In this paper, we report the performance of the SiPM arrays and the excellent resolution achieved by the digital Cherenkov prototype in the charge identification of the elements present in the beam.

  3. Gamma Ray Measurements at OMEGA with the Newest Gas Cherenkov Detector “GCD-3”

    NASA Astrophysics Data System (ADS)

    McEvoy, A. M.; Herrmann, H. W.; Kim, Y.; Zylstra, A. B.; Young, C. S.; Fatherley, V. E.; Lopez, F. E.; Oertel, J. A.; Sedillo, T. J.; Archuleta, T. N.; Aragonez, R. J.; Malone, R. M.; Horsfield, C. J.; Rubery, M.; Gales, S.; Leatherland, A.; Stoeffl, W.; Gatu Johnson, M.; Shmayda, W. T.; Batha, S. H.

    2016-05-01

    Initial results from the newest Gas Cherenkov Detector (GCD-3) are reported demonstrating improved performance over previous GCD iterations. Increased shielding and lengthening of the Cherenkov photon optical path have resulted in a diminished precursor signal with increased temporal separation between the precursor and the primary DT Cherenkov signal. Design changes resulted in a measured GCD-3 sensitivity comparable to GCD-1 at identical 100 psia CO2 operation. All metal gasket seals and pressure vessel certification to 400 psia operation allow for a GCD-3 lower Cherenkov threshold of 1.8 MeV using the fluorinated gas C2F6 as compared to the 6.3 MeV lower limit of GCD-1 and GCD-2. Calibration data will be used to benchmark GEANT4 and ACCEPT detector models. The GCD-3 acts as a prototype for the Super GCD being fielded at the National Ignition Facility (NIF) as part of the National Diagnostics Plan and will be installed at NIF in early 2016.

  4. Ring imaging Cherenkov detector prototype results for E665 at Fermilab

    SciTech Connect

    Coutrakon, G.B.; Biggs, B.; Dhawan, S.

    1986-02-01

    A proportional wire chamber (PWC) with cathode pad readout has been used to measure the position of Cherenkov photons produced by the passage of a 100 GeV muon beam in a five meter long radiator at Fermilab. The authors observe, on average, 6.2 photo-electrons per muon using Tetrakis (Dimethyl Amino) Ethylene (TMAE) as the photo ionizing vapor for detecting Cherenkov photons and 3.5 photo-electrons using triethylamine (TEA). The observed radius resolution was 3mm FWHM for the TEA data and 5mm FWHM for the TMAE data. In both cases a CaF/sub 2/ window transmitted the Cherenkov light from the radiator into the photon detector. The radiator gas was 20% argon and 80% helium producing Cherenkov rings with an average radius of 70mm. The detector described here offers the advantage of good timing resolution, (less than 100 nsec when using TEA), and high multi photon and multi ring reconstruction capability.

  5. Identification of large-transverse-momentum hadrons using a ring-imaging Cherenkov counter

    NASA Astrophysics Data System (ADS)

    McCarthy, R.; Adams, M.; Brown, C.; Coutrakon, G.; Charpak, G.; Finley, D.; Glass, H.; Hubbard, J. R.; Jaffe, D.; Jonckheere, A.; Jöstlein, H.; Kirz, J.; Mangeot, Ph.; Peisert, A.; Santiard, J. C.; Sauli, F.

    1986-07-01

    We have constructed and operated a large-aperture ring-imaging Cherenkov counter in a large-transverse-momentum experiment at Fermilab. Approximately 3 photons per relativistic particle are emitted in helium gas, focused by spherical mirrors and detected by multistep proportional chambers using a He/TEA gas mixture. Hadron identification is obtained from threshold to approximately 200 {GeV}/{c}.

  6. Experimental Verification of Reversed Cherenkov Radiation in Left-Handed Metamaterial

    SciTech Connect

    Xi Sheng; Chen Hongsheng; Wu, Bae-Ian; Kong, Jin Au; Jiang Tao; Ran Lixin; Huangfu Jiangtao; Chen Min

    2009-11-06

    By using a phased electromagnetic dipole array to model a moving charged particle, we experimentally verified a reversed Cherenkov radiation in the left-handed media in the frequency range from 8.1 to 9.5 GHz. Our results demonstrate the feasibility of new types of particle detectors and radiation generators.

  7. Gamma ray measurements at OMEGA with the newest gas Cherenkov Detector “GCD-3”

    DOE PAGESBeta

    McEvoy, A. M.; Herrmann, H. W.; Kim, Y.; Zylstra, A. B.; Young, C. S.; Fatherley, V. E.; Lopez, F. E.; Oertel, J. A.; Sedillo, T. J.; Archuleta, T. N.; et al

    2016-05-01

    Initial results from the newest Gas Cherenkov Detector (GCD-3) are reported demonstrating improved performance over previous GCD iterations. Increased shielding and lengthening of the Cherenkov photon optical path have resulted in a diminished precursor signal with increased temporal separation between the precursor and the primary DT Cherenkov signal. Design changes resulted in a measured GCD-3 sensitivity comparable to GCD-1 at identical 100 psia CO2 operation. All metal gasket seals and pressure vessel certification to 400 psia operation allow for a GCD-3 lower Cherenkov threshold of 1.8 MeV using the fluorinated gas C2F6 as compared to the 6.3 MeV lower limitmore » of GCD-1 and GCD-2. Calibration data will be used to benchmark GEANT4 and ACCEPT detector models. Lastly, the GCD-3 acts as a prototype for the Super GCD being fielded at the National Ignition Facility (NIF) as part of the National Diagnostics Plan and will be installed at NIF in early 2016.« less

  8. Study of the Planacon XP85012 photomultiplier characteristics for its use in a Cherenkov detector

    NASA Astrophysics Data System (ADS)

    Grigoryev, V. A.; Kaplin, V. A.; Karavicheva, T. L.; Kurepin, A. B.; Maklyaev, E. F.; Melikyan, Yu A.; Serebryakov, D. V.; Trzaska, W. H.; Tykmanov, E. M.

    2016-02-01

    Main properties of the multi-anode microchannel plate photomultiplier to be used in a Cherenkov detector are discussed. The laboratory test results obtained using irradiation of the MCP-PMT photocathode by picosecond optical laser pulses with different intensities (from single photon regime to the PMT saturation conditions) are presented.

  9. Study of wavelength-shifting chemicals for use in large-scale water Cherenkov detectors

    SciTech Connect

    Sweany, M; Bernstein, A; Dazeley, S; Dunmore, J; Felde, J; Svoboda, R; Tripathi, S M

    2011-09-21

    Cherenkov detectors employ various methods to maximize light collection at the photomultiplier tubes (PMTs). These generally involve the use of highly reflective materials lining the interior of the detector, reflective materials around the PMTs, or wavelength-shifting sheets around the PMTs. Recently, the use of water-soluble wavelength-shifters has been explored to increase the measurable light yield of Cherenkov radiation in water. These wave-shifting chemicals are capable of absorbing light in the ultravoilet and re-emitting the light in a range detectable by PMTs. Using a 250 L water Cherenkov detector, we have characterized the increase in light yield from three compounds in water: 4-Methylumbelliferone, Carbostyril-124, and Amino-G Salt. We report the gain in PMT response at a concentration of 1 ppm as: 1.88 {+-} 0.02 for 4-Methylumbelliferone, stable to within 0.5% over 50 days, 1.37 {+-} 0.03 for Carbostyril-124, and 1.20 {+-} 0.02 for Amino-G Salt. The response of 4-Methylumbelliferone was modeled, resulting in a simulated gain within 9% of the experimental gain at 1 ppm concentration. Finally, we report an increase in neutron detection performance of a large-scale (3.5 kL) gadolinium-doped water Cherenkov detector at a 4-Methylumbelliferone concentration of 1 ppm.

  10. 9125B ET Photomultiplier Tubes with a Wavelength Shifting Paint for a Gas Cherenkov Counter

    NASA Astrophysics Data System (ADS)

    Barcus, Scott; Averett, Todd; Wojtsekhowski, Bogdan

    2015-04-01

    This presentation will describe a method to increase the amount of Cherenkov light detected by photomultiplier tubes using a wavelength shifting paint and Electron Tubes' 9125B PMTs. A Cherenkov spectrum was generated via cosmic rays striking a polished rectangular fused silica crystal and observed by PMTs. By applying a wavelength shifting paint to the faces of the PMTs photons outside of the normal sensitivity range for the PMTs can be shifted into the sensitive range. A number of PMTs were tested with and without the paint to observe the change in the detected number of Cherenkov photons. The wavelength shifting paint was found to increase the number of photoelectrons seen by as much as 50 %. However, the response of individual tubes was found to be highly variable ranging from increases in light of 5 - 50 % with an average of 22.4 %. The variable nature of the PMTs' responses indicates that tubes may still need to be individually tested after the paint is applied to select the most desirable tubes. This method can be applied to the PMTs in a gas Cherenkov detector to increase the number of photons collected.

  11. Fast, Large-Area, Wide-Bandgap UV Photodetector for Cherenkov Light Detection

    NASA Technical Reports Server (NTRS)

    Wrbanek, John D.; Wrbanek, Susan Y.

    2013-01-01

    Due to limited resources available for power and space for payloads, miniaturizing and integrating instrumentation is a high priority for addressing the challenges of manned and unmanned deep space missions to high Earth orbit (HEO), near Earth objects (NEOs), Lunar and Martian orbits and surfaces, and outer planetary systems, as well as improvements to high-altitude aircraft safety. New, robust, and compact detectors allow future instrumentation packages more options in satisfying specific mission goals. A solid-state ultraviolet (UV) detector was developed with a theoretical fast response time and large detection area intended for application to Cherenkov detectors. The detector is based on the wide-bandgap semiconductor zinc oxide (ZnO), which in a bridge circuit can detect small, fast pulses of UV light like those required for Cherenkov detectors. The goal is to replace the role of photomultiplier tubes in Cherenkov detectors with these solid-state devices, saving on size, weight, and required power. For improving detection geometry, a spherical detector to measure high atomic number and energy (HZE) ions from any direction has been patented as part of a larger space radiation detector system. The detector will require the development of solid-state UV photodetectors fast enough (2 ns response time or better) to detect the shockwave of Cherenkov light emitted as the ions pass through a quartz, sapphire, or acrylic ball. The detector must be small enough to fit in the detector system structure, but have an active area large enough to capture enough Cherenkov light from the sphere. The detector is fabricated on bulk single-crystal undoped ZnO. Inter - digitated finger electrodes and contact pads are patterned via photolithography, and formed by sputtered metal of silver, platinum, or other high-conductivity metal.

  12. MO-A-BRD-06: In Vivo Cherenkov Video Imaging to Verify Whole Breast Irradiation Treatment

    SciTech Connect

    Zhang, R; Glaser, A; Jarvis, L; Gladstone, D; Andreozzi, J; Hitchcock, W; Pogue, B

    2014-06-15

    Purpose: To show in vivo video imaging of Cherenkov emission (Cherenkoscopy) can be acquired in the clinical treatment room without affecting the normal process of external beam radiation therapy (EBRT). Applications of Cherenkoscopy, such as patient positioning, movement tracking, treatment monitoring and superficial dose estimation, were examined. Methods: In a phase 1 clinical trial, including 12 patients undergoing post-lumpectomy whole breast irradiation, Cherenkov emission was imaged with a time-gated ICCD camera synchronized to the radiation pulses, during 10 fractions of the treatment. Images from different treatment days were compared by calculating the 2-D correlations corresponding to the averaged image. An edge detection algorithm was utilized to highlight biological features, such as the blood vessels. Superficial dose deposited at the sampling depth were derived from the Eclipse treatment planning system (TPS) and compared with the Cherenkov images. Skin reactions were graded weekly according to the Common Toxicity Criteria and digital photographs were obtained for comparison. Results: Real time (fps = 4.8) imaging of Cherenkov emission was feasible and feasibility tests indicated that it could be improved to video rate (fps = 30) with system improvements. Dynamic field changes due to fast MLC motion were imaged in real time. The average 2-D correlation was about 0.99, suggesting the stability of this imaging technique and repeatability of patient positioning was outstanding. Edge enhanced images of blood vessels were observed, and could serve as unique biological markers for patient positioning and movement tracking (breathing). Small discrepancies exists between the Cherenkov images and the superficial dose predicted from the TPS but the former agreed better with actual skin reactions than did the latter. Conclusion: Real time Cherenkoscopy imaging during EBRT is a novel imaging tool that could be utilized for patient positioning, movement tracking

  13. Design Concepts for the Cherenkov Telescope Array CTA: An Advanced Facility for Ground-Based High-Energy Gamma-Ray Astronomy

    SciTech Connect

    Actis, M

    2012-04-17

    Ground-based gamma-ray astronomy has had a major breakthrough with the impressive results obtained using systems of imaging atmospheric Cherenkov telescopes. Ground-based gamma-ray astronomy has a huge potential in astrophysics, particle physics and cosmology. CTA is an international initiative to build the next generation instrument, with a factor of 5-10 improvement in sensitivity in the 100 GeV-10 TeV range and the extension to energies well below 100 GeV and above 100 TeV. CTA will consist of two arrays (one in the north, one in the south) for full sky coverage and will be operated as open observatory. The design of CTA is based on currently available technology. This document reports on the status and presents the major design concepts of CTA.

  14. Dark matter searches with Cherenkov telescopes: nearby dwarf galaxies or local galaxy clusters?

    NASA Astrophysics Data System (ADS)

    Sánchez-Conde, Miguel A.; Cannoni, Mirco; Zandanel, Fabio; Gómez, Mario E.; Prada, Francisco

    2011-12-01

    In this paper, we compare dwarf galaxies and galaxy clusters in order to elucidate which object class is the best target for gamma-ray DM searches with imaging atmospheric Cherenkov telescopes (IACTs). We have built a mixed dwarfs+clusters sample containing some of the most promising nearby dwarf galaxies (Draco, Ursa Minor, Wilman 1 and Segue 1) and local galaxy clusters (Perseus, Coma, Ophiuchus, Virgo, Fornax, NGC 5813 and NGC 5846), and then compute their DM annihilation flux profiles by making use of the latest modeling of their DM density profiles. We also include in our calculations the effect of DM substructure. Willman 1 appears as the best candidate in the sample. However, its mass modeling is still rather uncertain, so probably other candidates with less uncertainties and quite similar fluxes, namely Ursa Minor and Segue 1, might be better options. As for galaxy clusters, Virgo represents the one with the highest flux. However, its large spatial extension can be a serious handicap for IACT observations and posterior data analysis. Yet, other local galaxy cluster candidates with more moderate emission regions, such as Perseus, may represent good alternatives. After comparing dwarfs and clusters, we found that the former exhibit annihilation flux profiles that, at the center, are roughly one order of magnitude higher than those of clusters, although galaxy clusters can yield similar, or even higher, integrated fluxes for the whole object once substructure is taken into account. Even when any of these objects are strictly point-like according to the properties of their annihilation signals, we conclude that dwarf galaxies are best suited for observational strategies based on the search of point-like sources, while galaxy clusters represent best targets for analyses that can deal with rather extended emissions. Finally, we study the detection prospects for present and future IACTs in the framework of the constrained minimal supersymmetric standard model. We

  15. Dark Matter Searches with Cherenkov Telescopes: Nearby Dwarf Galaxies or Local Galaxy Clusters?

    SciTech Connect

    Sanchez-Conde, Miguel A.; Cannoni, Mirco; Zandanel, Fabio; Gomez, Mario E.; Prada, Francisco; /IAA, Granada

    2012-06-06

    In this paper, we compare dwarf galaxies and galaxy clusters in order to elucidate which object class is the best target for gamma-ray DM searches with imaging atmospheric Cherenkov telescopes (IACTs). We have built a mixed dwarfs+clusters sample containing some of the most promising nearby dwarf galaxies (Draco, Ursa Minor, Wilman 1 and Segue 1) and local galaxy clusters (Perseus, Coma, Ophiuchus, Virgo, Fornax, NGC 5813 and NGC 5846), and then compute their DM annihilation flux profiles by making use of the latest modeling of their DM density profiles. We also include in our calculations the effect of DM substructure. Willman 1 appears as the best candidate in the sample. However, its mass modeling is still rather uncertain, so probably other candidates with less uncertainties and quite similar fluxes, namely Ursa Minor and Segue 1, might be better options. As for galaxy clusters, Virgo represents the one with the highest flux. However, its large spatial extension can be a serious handicap for IACT observations and posterior data analysis. Yet, other local galaxy cluster candidates with more moderate emission regions, such as Perseus, may represent good alternatives. After comparing dwarfs and clusters, we found that the former exhibit annihilation flux profiles that, at the center, are roughly one order of magnitude higher than those of clusters, although galaxy clusters can yield similar, or even higher, integrated fluxes for the whole object once substructure is taken into account. Even when any of these objects are strictly point-like according to the properties of their annihilation signals, we conclude that dwarf galaxies are best suited for observational strategies based on the search of point-like sources, while galaxy clusters represent best targets for analyses that can deal with rather extended emissions. Finally, we study the detection prospects for present and future IACTs in the framework of the constrained minimal supersymmetric standard model. We

  16. e-A PHYSICS AT A COLLIDER.

    SciTech Connect

    G. T. GARVEY

    2001-01-09

    An electron-nucleus (e-A) collider with center-of-mass energy in excess of 50 GeV per electron-nucleon collision will allow the physics community to obtain unprecedented new knowledge of the partonic structure of nuclei. If reliable information is to be extracted on these partonic densities, it is essential to realize that with our current level of understanding of QCD, momentum transfers to the struck partons greater than 1 GeV/c are necessary. This requirement puts a priority on high center-of-mass energy if partonic densities are to be measured over a wide range. Comparing the partonic structure of the free nucleon to that of bound nucleons and measuring the systematic changes in that structure as a function of nucleon number (A) will provide deeper insight into the origins and dynamics of nuclear binding. In addition, e-A collisions will allow the exploration of partonic densities appreciably higher than is accessible in e-p collisions. An e-A collider will allow one to measure the gluonic structure functions of nuclei down to x {approx} 10{sup -3}, information valuable in its own right and essential to a quantitative understanding of highly relativistic A-A collisions. The time-space evolution of partons can only be investigated by studying the modifications of hard collisions that take place when nuclear targets are employed. In a hard collision the partonic fragments interact, hadronize, and reinteract on their way to the distant detectors without revealing their evolution into the hadrons finally detected. Nuclear targets of differing A place varying amounts of nuclear matter in proximity to the hard collision producing unique information about the quantum fluctuations of incident projectile prior to the collision and on the early evolution of the produced partons. Using charged leptons (e, {mu}) to investigate this physics has been the richest source of information to date and extending the reach of these investigations by the constructing an e -A collider

  17. Vasorelaxation Effect of Estrone Derivate EA204 in Rabbit Aorta

    PubMed Central

    Li, Wei-Qi

    2016-01-01

    Estrogen and its derivatives exert vascular protective effects, but the underlying mechanisms remain to be studied fully. Objective. To investigate the vasorelaxation effect and related mechanisms of an estrone derivate EA204[3-(2-piperidin-1-yl)-ethoxy-estra-1, 3, 5 (10)-trien-17-one] on isolated arterial preparation from rabbit thoracic aorta. Methods. Aortic rings from rabbit thoracic aorta were prepared and held in small organ bath filled with Krebs solution; tension change was recorded by a multichannel physiological signal collection and handling system. Results. EA204 (10−5 to 10−3 M) induced a concentration-dependent relaxation of aortic rings with endothelium and without endothelium. In denuded arterial preparations, EA204 had a potent relaxing effect on isolated arterial preparations contracted with phenylephrine, norepinephrine, and high-K+ solution or BaCl2. Mechanism study indicates that EA204 relaxes aortic rings by inhibiting Ca2+ channels (both receptor-operating Ca2+ channels and the voltage-dependent Ca2+ channels were involved) to decrease extracellular Ca2+ influx and intracellular Ca2+ release. EA204 is different from verapamil, which is a noncompetitive inhibitor of Ca2+ channels. In addition, K+ channels opening may contribute to this vasorelaxation effect. Conclusion. EA204 had a potent endothelium-independent relaxing effect on isolated arterial preparation by inhibiting Ca2+ channels and opening K+ channels. The results suggest that EA204 is a potential compound for treatment of cardiovascular diseases in postmenopausal women. PMID:27190689

  18. 47 CFR 11.55 - EAS operation during a State or Local Area emergency.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false EAS operation during a State or Local Area... SYSTEM (EAS) Emergency Operations § 11.55 EAS operation during a State or Local Area emergency. (a) All... conducted as specified in State and Local Area EAS Plans. The plans must list all authorized...

  19. 47 CFR 11.54 - EAS operation during a National Level emergency.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false EAS operation during a National Level emergency. 11.54 Section 11.54 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Emergency Operations § 11.54 EAS operation during a National Level emergency. (a) The EAS Operating Handbook summarizes the procedures...

  20. 47 CFR 11.55 - EAS operation during a State or Local Area emergency.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false EAS operation during a State or Local Area emergency. 11.55 Section 11.55 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Emergency Operations § 11.55 EAS operation during a State or Local Area emergency. (a) All EAS Participants within a state...

  1. 7 CFR 520.6 - Preparation of an Environmental Assessment (EA).

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 6 2014-01-01 2014-01-01 false Preparation of an Environmental Assessment (EA). 520.6... Preparation of an Environmental Assessment (EA). (a) Actions requiring EA. The following actions would... in 40 CFR 1501.5. (c) Format and conclusion. An EA can be in any format provided it covers in...

  2. 7 CFR 520.6 - Preparation of an Environmental Assessment (EA).

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 7 Agriculture 6 2010-01-01 2010-01-01 false Preparation of an Environmental Assessment (EA). 520.6... Preparation of an Environmental Assessment (EA). (a) Actions requiring EA. The following actions would... in 40 CFR 1501.5. (c) Format and conclusion. An EA can be in any format provided it covers in...

  3. 7 CFR 520.6 - Preparation of an Environmental Assessment (EA).

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 7 Agriculture 6 2013-01-01 2013-01-01 false Preparation of an Environmental Assessment (EA). 520.6... Preparation of an Environmental Assessment (EA). (a) Actions requiring EA. The following actions would... in 40 CFR 1501.5. (c) Format and conclusion. An EA can be in any format provided it covers in...

  4. Development of a diagnostic technique based on Cherenkov effect for measurements of fast electrons in fusion devices.

    PubMed

    Plyusnin, V V; Jakubowski, L; Zebrowski, J; Duarte, P; Malinowski, K; Fernandes, H; Silva, C; Rabinski, M; Sadowski, M J

    2012-08-01

    A diagnostic technique based on the Cherenkov effect is proposed for detection and characterization of fast (super-thermal and runaway) electrons in fusion devices. The detectors of Cherenkov radiation have been specially designed for measurements in the ISTTOK tokamak. Properties of several materials have been studied to determine the most appropriate one to be used as a radiator of Cherenkov emission in the detector. This technique has enabled the detection of energetic electrons (70 keV and higher) and the determination of their spatial and temporal variations in the ISTTOK discharges. Measurement of hard x-ray emission has also been carried out in experiments for validation of the measuring capabilities of the Cherenkov-type detector and a high correlation was found between the data of both diagnostics. A reasonable agreement was found between experimental data and the results of numerical modeling of the runaway electron generation in ISTTOK. PMID:22938292

  5. Development of a diagnostic technique based on Cherenkov effect for measurements of fast electrons in fusion devices

    SciTech Connect

    Plyusnin, V. V.; Duarte, P.; Fernandes, H.; Silva, C.

    2012-08-15

    A diagnostic technique based on the Cherenkov effect is proposed for detection and characterization of fast (super-thermal and runaway) electrons in fusion devices. The detectors of Cherenkov radiation have been specially designed for measurements in the ISTTOK tokamak. Properties of several materials have been studied to determine the most appropriate one to be used as a radiator of Cherenkov emission in the detector. This technique has enabled the detection of energetic electrons (70 keV and higher) and the determination of their spatial and temporal variations in the ISTTOK discharges. Measurement of hard x-ray emission has also been carried out in experiments for validation of the measuring capabilities of the Cherenkov-type detector and a high correlation was found between the data of both diagnostics. A reasonable agreement was found between experimental data and the results of numerical modeling of the runaway electron generation in ISTTOK.

  6. 47 CFR 11.46 - EAS public service announcements.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 11.46 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS.... Such announcements and programs may not be a part of alerts or tests, and may not simulate or attempt to copy alert tones or codes....

  7. 47 CFR 11.46 - EAS public service announcements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 11.46 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS.... Such announcements and programs may not be a part of alerts or tests, and may not simulate or attempt to copy alert tones or codes....

  8. 47 CFR 11.46 - EAS public service announcements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 11.46 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS.... Such announcements and programs may not be a part of alerts or tests, and may not simulate or attempt to copy alert tones or codes....

  9. 47 CFR 11.46 - EAS public service announcements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 11.46 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS.... Such announcements and programs may not be a part of alerts or tests, and may not simulate or attempt to copy alert tones or codes....

  10. 47 CFR 11.46 - EAS public service announcements.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 11.46 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS.... Such announcements and programs may not be a part of alerts or tests, and may not simulate or attempt to copy alert tones or codes....

  11. Analysis of the hadron component in E.A.S.

    NASA Technical Reports Server (NTRS)

    Procureur, J.; Stamenov, J. N.; Stavrev, P. V.; Ushev, S. Z.

    1985-01-01

    Hadrons in extensive air showers (E.A.S.) provide direct information about high energy interactions. As a rule the biases pertaining to different shower array arrangements have a relative large influence for the basic phenomenological characteristics of the E.A.S. hadron component. In this situation, the problem of the correct comparison between model calculated and experimental characteristics is of great importance for the reliability of the derived conclusions about the high energy interaction characteristics.

  12. On the determination of the depth of EAS development maximum using the lateral distribution of Cerenkov light at distances 150 M from EAS axis

    NASA Astrophysics Data System (ADS)

    Aliev, N.; Alimov, T.; Kakhkharov, M.; Makhmudov, B. M.; Rakhimova, N.; Tashpulatov, R.; Kalmykov, N. N.; Khristiansen, G. B.; Prosin, V. V.

    1985-08-01

    The Samarkand extensive air showers (EAS) array was used to measure the mean and individual lateral distribution functions (LDF) of EAS Cerenkov light. The analysis of the individual parameters b showed that the mean depth of EAS maximum and the variance of the depth distribution of maxima of EAS with energies of approx. 2x10 to the 15th power eV can properly be described in terms of Kaidalov-Martirosyan quark-gluon string model (QGSM).

  13. On the determination of the depth of EAS development maximum using the lateral distribution of Cerenkov light at distances 150 m from EAS axis

    NASA Technical Reports Server (NTRS)

    Aliev, N.; Kakhkharov, M.; Makhmudov, B. M.; Tashpulatov, R.; Khristiansen, G. B.; Alimov, T.; Rakhimova, N.; Kalmykov, N. N.; Prosin, V. V.

    1985-01-01

    The Samarkand extensive air showers (EAS) array was used to measure the mean and individual lateral distribution functions (LDF) of EAS Cerenkov light. The analysis of the individual parameters b showed that the mean depth of EAS maximum and the variance of the depth distribution of maxima of EAS with energies of approx. 2x10 to the 15th power eV can properly be described in terms of Kaidalov-Martirosyan quark-gluon string model (QGSM).

  14. LPM Interference and Cherenkov-like Gluon Bremsstrahlung in DenseMatter

    SciTech Connect

    Majumder, Abhijit; Wang, Xin-Nian

    2005-07-26

    Gluon bremsstrahlung induced by multiple parton scattering in a finite dense medium has a unique angular distribution with respect to the initial parton direction. A dead-cone structure with an opening angle; theta2{sub 0}; approx 2(1-z)/(zLE) for gluons with fractional energy z arises from the Landau-Pomeran chuck-Migdal (LPM) interference. In a medium where the gluon's dielectric constant is; epsilon>1, the LPM interference pattern is shown to become Cherenkov-like with an increased opening angle determined by the dielectric constant$/cos2/theta{sub c}=z+(1-z)//epsilon$. For a large dielectric constant/epsilon; gg 1+2/z2LE, the corresponding total radiative parton energy loss is about twice that from normal gluon bremsstrahlung. Implications of this Cherenkov-like gluon bremsstrahlung to the jet correlation pattern in high-energy heavy-ion collisions is discussed.

  15. An overview on mirrors for Cherenkov telescopes manufactured by glass cold-shaping technology

    NASA Astrophysics Data System (ADS)

    Canestrari, Rodolfo; Sironi, Giorgia

    2015-09-01

    The cold glass-slumping technique is a low cost processing developed at INAF-Osservatorio Astronomico di Brera for the manufacturing of mirrors for Cherenkov telescopes. This technology is based on the shaping of thin glass foils by means of bending at room temperature. The glass foils are thus assembled into a sandwich structure for retaining the imposed shape by the use of a honeycomb core. The mirrors so manufactured employ commercial off-the-shelf materials thus allowing a competitive cost and production time. They show very low weight, rigidity and environmental robustness. In this contribution we give an overview on the most recent results achieved from the adoption of the cold-shaping technology to different projects of Cherenkov telescopes. We show the variety of optical shapes implemented ranging from those spherical with long radius of curvature up to the most curved free form ones.

  16. Spin-Cherenkov effect in a magnetic nanostrip with interfacial Dzyaloshinskii-Moriya interaction

    NASA Astrophysics Data System (ADS)

    Xia, Jing; Zhang, Xichao; Yan, Ming; Zhao, Weisheng; Zhou, Yan

    2016-05-01

    Spin-Cherenkov effect enables strong excitations of spin waves (SWs) with nonlinear wave dispersions. The Dzyaloshinskii-Moriya interaction (DMI) results in anisotropy and nonreciprocity of SWs propagation. In this work, we study the effect of the interfacial DMI on SW Cherenkov excitations in permalloy thin-film strips within the framework of micromagnetism. By performing micromagnetic simulations, it is shown that coherent SWs are excited when the velocity of a moving magnetic source exceeds the propagation velocity of the SWs. Moreover, the threshold velocity of the moving magnetic source with finite DMI can be reduced compared to the case of zero DMI. It thereby provides a promising route towards efficient spin wave generation and propagation, with potential applications in spintronic and magnonic devices.

  17. Spin-Cherenkov effect in a magnetic nanostrip with interfacial Dzyaloshinskii-Moriya interaction.

    PubMed

    Xia, Jing; Zhang, Xichao; Yan, Ming; Zhao, Weisheng; Zhou, Yan

    2016-01-01

    Spin-Cherenkov effect enables strong excitations of spin waves (SWs) with nonlinear wave dispersions. The Dzyaloshinskii-Moriya interaction (DMI) results in anisotropy and nonreciprocity of SWs propagation. In this work, we study the effect of the interfacial DMI on SW Cherenkov excitations in permalloy thin-film strips within the framework of micromagnetism. By performing micromagnetic simulations, it is shown that coherent SWs are excited when the velocity of a moving magnetic source exceeds the propagation velocity of the SWs. Moreover, the threshold velocity of the moving magnetic source with finite DMI can be reduced compared to the case of zero DMI. It thereby provides a promising route towards efficient spin wave generation and propagation, with potential applications in spintronic and magnonic devices. PMID:27143311

  18. Vacuum Cherenkov radiation in quantum electrodynamics with high-energy Lorentz violation

    SciTech Connect

    Anselmi, Damiano; Taiuti, Martina

    2011-03-01

    We study phenomena predicted by a renormalizable, CPT invariant extension of the standard model that contains higher-dimensional operators and violates Lorentz symmetry explicitly at energies greater than some scale {Lambda}{sub L}. In particular, we consider the Cherenkov radiation in vacuo. In a rather general class of dispersion relations, there exists an energy threshold above which radiation is emitted. The threshold is enhanced in composite particles by a sort of kinematic screening mechanism. We study the energy loss and compare the predictions of our model with known experimental bounds on Lorentz violating parameters and observations of ultrahigh-energy cosmic rays. We argue that the scale of Lorentz violation {Lambda}{sub L} (with preserved CPT invariance) can be smaller than the Planck scale, actually as small as 10{sup 14}-10{sup 15} GeV. Our model also predicts the Cherenkov radiation of neutral particles.

  19. Spin-Cherenkov effect in a magnetic nanostrip with interfacial Dzyaloshinskii-Moriya interaction

    PubMed Central

    Xia, Jing; Zhang, Xichao; Yan, Ming; Zhao, Weisheng; Zhou, Yan

    2016-01-01

    Spin-Cherenkov effect enables strong excitations of spin waves (SWs) with nonlinear wave dispersions. The Dzyaloshinskii-Moriya interaction (DMI) results in anisotropy and nonreciprocity of SWs propagation. In this work, we study the effect of the interfacial DMI on SW Cherenkov excitations in permalloy thin-film strips within the framework of micromagnetism. By performing micromagnetic simulations, it is shown that coherent SWs are excited when the velocity of a moving magnetic source exceeds the propagation velocity of the SWs. Moreover, the threshold velocity of the moving magnetic source with finite DMI can be reduced compared to the case of zero DMI. It thereby provides a promising route towards efficient spin wave generation and propagation, with potential applications in spintronic and magnonic devices. PMID:27143311

  20. Cherenkov radiation from a relativistic annular electron beam propagating through a dielectric loaded waveguide

    NASA Astrophysics Data System (ADS)

    Uhm, H. S.

    1981-11-01

    The stability properties of the free-streaming mode (space-charge wave) in a relativistic annular electron beam with radius R sub 0 propagating through a dielectric loaded waveguide is studied in connection with the Cherenkov radiation. The stability analysis is carried out within the framework of the linearized Vlasov-Maxwell equations for an electron distribution function, where all electrons have a Lorentzian distribution in the axial canonical momentum. One of the most significant features of the analysis is that, for some ranges of physical parameters, a strong mode coupling between the vacuum dielectric waveguide and free streaming modes occurs, exhibiting possibilities of a Cherenkov radiation. It is found that the typical maximum growth rate of instability is a few percent of c/R sub 0, c being the speed of light in vacuo.

  1. Proposal of coherent Cherenkov radiation matched to circular plane wave for intense terahertz light source

    NASA Astrophysics Data System (ADS)

    Sei, Norihiro; Sakai, Takeshi; Hayakawa, Ken; Tanaka, Toshinari; Hayakawa, Yasushi; Nakao, Keisuke; Nogami, Kyoko; Inagaki, Manabu

    2015-10-01

    We propose a high-peak-power terahertz-wave source based on an electron accelerator. By passing an electron beam through a hollow conical dielectric with apex facing the incident electron beam, the wave front of coherent Cherenkov radiation generated on the inner surface of the hollow conical dielectric matches the basal plane. Using the electron beam generated at the Laboratory for Electron Beam Research and Application at Nihon University, the calculated power of coherent Cherenkov radiation that matched the circular plane (CCR-MCP) was above 1 MW per micropulse with a short interval of 350 ps, for wavelengths ranging from 0.5 to 5 mm. The electron beam is not lost for generating the CCR-MCP beam by using the hollow conical dielectric. It is possible to combine the CCR-MCP beams with other light sources based on an accelerator.

  2. Studies of Multi-Anode PMTs for a Ring Imaging Cherenkov for CLAS12

    NASA Astrophysics Data System (ADS)

    Lendacky, Andrew; Benmokhtar, Fatiha; Kubarovsky, Valery; Kim, Andrey

    2015-10-01

    At Thomas Jefferson National Accelerator Facility (TJNAF), the CLAS12 detector in Hall B is undergoing an upgrade. A Ring Imaging Cherenkov (R.I.C.H) detector is being built to improve particle identification in the 3-8 GeV/c momentum range. Approximately four hundred Hamamatsu H121700 Multi-Anode Photomultiplier Tubes (MA-PMTs) are being used in this detector to measure photons emitted through Cherenkov Radiation. These MA-PMTs' characteristics are being tested and measured, and I will be presenting my work about the crosstalk study. Crosstalk is the occurrence of incident light striking one area of the photocathode, but is additionally measured in nearby areas. By using a Class 3b laser in the 470 nm wavelength, and an optical density resembling the single photon emission spectrum, the crosstalk for the H121700 MA-PMTs are measured and categorized into a database for future reference.

  3. Cherenkov-type diamond detectors for measurements of fast electrons in the TORE-SUPRA tokamak

    SciTech Connect

    Jakubowski, L.; Sadowski, M. J.; Zebrowski, J.; Rabinski, M.; Malinowski, K.; Mirowski, R.; Lotte, Ph.; Gunn, J.; Pascal, J-Y.; Colledani, G.; Basiuk, V.; Goniche, M.; Lipa, M.

    2010-01-15

    The paper presents a schematic design and tests of a system applicable for measurements of fast electron pulses emitted from high-temperature plasma generated inside magnetic confinement fusion machines, and particularly in the TORE-SUPRA facility. The diagnostic system based on the registration of the Cherenkov radiation induced by fast electrons within selected solid radiators is considered, and electron low-energy thresholds for different radiators are given. There are some estimates of high thermal loads, which might be deposited by intense electron beams upon parts of the diagnostic equipment within the TORE-SUPRA device. There are some proposed measures to overcome this difficulty by the selection of appropriate absorption filters and Cherenkov radiators, and particularly by the application of a fast-moving reciprocating probe. The paper describes the measuring system, its tests, as well as some results of the preliminary measurements of fast electrons within TORE-SUPRA facility.

  4. Photonic chip-based optical frequency comb using soliton Cherenkov radiation.

    PubMed

    Brasch, V; Geiselmann, M; Herr, T; Lihachev, G; Pfeiffer, M H P; Gorodetsky, M L; Kippenberg, T J

    2016-01-22

    Optical solitons are propagating pulses of light that retain their shape because nonlinearity and dispersion balance each other. In the presence of higher-order dispersion, optical solitons can emit dispersive waves via the process of soliton Cherenkov radiation. This process underlies supercontinuum generation and is of critical importance in frequency metrology. Using a continuous wave-pumped, dispersion-engineered, integrated silicon nitride microresonator, we generated continuously circulating temporal dissipative Kerr solitons. The presence of higher-order dispersion led to the emission of red-shifted soliton Cherenkov radiation. The output corresponds to a fully coherent optical frequency comb that spans two-thirds of an octave and whose phase we were able to stabilize to the sub-Hertz level. By preserving coherence over a broad spectral bandwidth, our device offers the opportunity to develop compact on-chip frequency combs for frequency metrology or spectroscopy. PMID:26721682

  5. Dispersion relation and growth rate in a Cherenkov free electron laser: Finite axial magnetic field

    SciTech Connect

    Kheiri, Golshad; Esmaeilzadeh, Mahdi

    2013-12-15

    A theoretical analysis is presented for dispersion relation and growth rate in a Cherenkov free electron laser with finite axial magnetic field. It is shown that the growth rate and the resonance frequency of Cherenkov free electron laser increase with increasing axial magnetic field for low axial magnetic fields, while for high axial magnetic fields, they go to a saturation value. The growth rate and resonance frequency saturation values are exactly the same as those for infinite axial magnetic field approximation. The effects of electron beam self-fields on growth rate are investigated, and it is shown that the growth rate decreases in the presence of self-fields. It is found that there is an optimum value for electron beam density and Lorentz relativistic factor at which the maximum growth rate can take place. Also, the effects of velocity spread of electron beam are studied and it is found that the growth rate decreases due to the electron velocity spread.

  6. Photonic chip-based optical frequency comb using soliton Cherenkov radiation

    NASA Astrophysics Data System (ADS)

    Brasch, V.; Geiselmann, M.; Herr, T.; Lihachev, G.; Pfeiffer, M. H. P.; Gorodetsky, M. L.; Kippenberg, T. J.

    2016-01-01

    Optical solitons are propagating pulses of light that retain their shape because nonlinearity and dispersion balance each other. In the presence of higher-order dispersion, optical solitons can emit dispersive waves via the process of soliton Cherenkov radiation. This process underlies supercontinuum generation and is of critical importance in frequency metrology. Using a continuous wave-pumped, dispersion-engineered, integrated silicon nitride microresonator, we generated continuously circulating temporal dissipative Kerr solitons. The presence of higher-order dispersion led to the emission of red-shifted soliton Cherenkov radiation. The output corresponds to a fully coherent optical frequency comb that spans two-thirds of an octave and whose phase we were able to stabilize to the sub-Hertz level. By preserving coherence over a broad spectral bandwidth, our device offers the opportunity to develop compact on-chip frequency combs for frequency metrology or spectroscopy.

  7. Studies of signal waveforms from the water-cherenkov detectors of the Pierre Auger Observatory

    SciTech Connect

    Allison, P.S.; Bui-Duc, H.; Chye, J.; Dagoret-Campagne, S.; Dorofeev, A.; Matthews, J.; Nitz, D.F.; Ranchon, S.; Urban, M.; Veberic, D.; Watson, A.A.; Wileman, C.

    2005-08-01

    The ground array of the Pierre Auger Observatory will consist of 1600 water-Cherenkov detectors. Such detectors give signals which can help differentiate between muons and electrons in extensive air showers. The relative numbers of muons and electrons is sensitive to the type of primary particle which initiated the shower. Results are presented using methods which describe the muon content and related information, such as the time structure of the shower front.

  8. Cherenkov radiation fluence estimates in tissue for molecular imaging and therapy applications.

    PubMed

    Glaser, Adam K; Zhang, Rongxiao; Andreozzi, Jacqueline M; Gladstone, David J; Pogue, Brian W

    2015-09-01

    Cherenkov radiation has recently emerged as an interesting phenomenon for a number of applications in the biomedical sciences. Its unique properties, including broadband emission spectrum, spectral weight in the ultraviolet and blue wavebands, and local generation of light within a given tissue, have made it an attractive new source of light within tissue for molecular imaging and phototherapy applications. While several studies have investigated the total Cherenkov light yield from radionuclides in units of [photons/decay], further consideration of the light propagation in tissue is necessary to fully consider the utility of this signal in vivo. Therefore, to help further guide the development of this novel field, quantitative estimates of the light fluence rate of Cherenkov radiation from both radionuclides and radiotherapy beams in a biological tissue are presented for the first time. Using Monte Carlo simulations, these values were found to be on the order of 0.01-1 nW cm(-2) per MBq g(-1) for radionuclides, and 1-100 μW cm(-2) per Gy s(-1) for external radiotherapy beams, dependent on the given waveband, optical properties, and radiation source. For phototherapy applications, the total light fluence was found to be on the order of nJ cm(-2) for radionuclides, and mJ cm(-2) for radiotherapy beams. The results indicate that diagnostic potential is reasonable for Cherenkov excitation of molecular probes, but phototherapy may remain elusive at such exceedingly low fluence values. The results of this study are publicly available for distribution online at www.dartmouth.edu/optmed/. PMID:26270125

  9. First calibration of a Cherenkov beam loss sensor at ALICE using SiPM

    NASA Astrophysics Data System (ADS)

    Intermite, A.; Putignano, M.; Wolski, A.

    2012-06-01

    The need for real-time monitoring of beam losses, including evaluation of their intensity and localization of their exact position, together with the possibility to overcome the limitations due to the reduced space for the diagnostics, makes exploitation of the Cherenkov effect in optical fibres, one of the most suitable candidates for beam loss monitoring. In this article, we report on the first tests of an optical fibre beam loss monitor based on large numerical aperture pure silica fibres and silicon photomultipliers. The tests were carried out at the ALICE accelerator research and development facility, Daresbury Laboratories, UK. In contrast to the results already published where the fibres are longitudinally placed with respect to the accelerator beam path and the losses are multidirectional charged particle showers, for the first time a dedicated set-up with an incident accelerator beam impinging directly on the optical fibre was used for optimizing the collection efficiency of the Cherenkov effect as a function of the incident angle by changing the fibre direction. For this purpose large core fibres were used together with the latest generation silicon detector instead of the standard photomultiplier tubes commonly used for Cherenkov beam loss monitoring. The experiments described in this contribution aim to demonstrate the suitability of the optical fibre sensor for loss monitoring, to optimize the Collection Efficiency (CE) of the Cherenkov photons inside the fibre as a function of the particle incident angle, to calibrate the sensor and calculate its sensitivity, and to understand the limits of temporal resolution of losses from different bunches in the accelerator.

  10. Picosecond Cherenkov detectors for high-energy heavy ion experiments at LHEP/JINR

    NASA Astrophysics Data System (ADS)

    Yurevich, V. I.; Batenkov, O. I.

    2016-07-01

    The modular Cherenkov detectors based on MCP-PMTs are developed for study Au+Au collisions in MPD and BM@N experiments with beams of Nuclotron and future collider NICA in Dubna. The aim of the detector is fast and effective triggering nucleus-nucleus collisions and generation of start signal for TOF detectors. The detector performance is studied with MC simulation and test measurements with a beam of Nuclotron.

  11. Prospects and Challenges for a Large Water Cherenkov Detector for LBNE

    SciTech Connect

    Whitehead, L.

    2011-10-06

    The Long Baseline Neutrino Experiment (LBNE) is a proposed experiment that would send a beam of muon neutrinos from Fermilab to the DUSEL (Deep Underground Science and Engineering Laboratory) facility in South Dakota, a 1300 km baseline. One possible configuration for the far detector is one or more large water Cherenkov modules with a fiducial mass of at least 100 kilotons each. The prospects and challenges of such a detector, including the current design, will be presented.

  12. Sub-millimeter Bunch Length Non-invasive Diagnostic Based on the Diffraction and Cherenkov Radiation

    NASA Astrophysics Data System (ADS)

    Shevelev, M.; Deng, H.; Potylitsyn, A.; Naumenko, G.; Zhang, J.; Lu, Sh; Gogolev, S.; Shkitov, D.

    2012-05-01

    A layout for the investigation the coherent Cherenkov radiation from a dielectric target with a large spectral dispersion and the coherent diffraction radiation from a conducting screen as a tool for non-invasive longitudinal electron beam profile diagnostics are proposed for the 20~30MeV Linac at Shanghai Institute of Applied Physics (SINAP). In this paper the status of the joint experiment and future plans are presented.

  13. Cherenkov detection of cosmic rays in Hanoi: Response to low signals

    NASA Astrophysics Data System (ADS)

    Thao, N. T.; Anh, P. T.; Darriulat, P.; Diep, P. N.; Dong, P. N.; Hiep, N. V.; Hoai, D. T.; Nhung, P. T. T.

    2013-05-01

    A replica of one of the 1660 Cherenkov detectors used in the ground array of the Pierre Auger Cosmic Ray Observatory in Argentina has been constructed on the roof of the VATLY astrophysics laboratory in Ha Noi (Viet Nam). We report on measurements of low amplitude signals using the detector to study event pairs occurring within a small time window. The data include time autocorrelation and charge distributions.

  14. The ASTRI SST-2M prototype for the next generation of Cherenkov telescopes: a single framework approach from requirement analysis to integration and verification strategy definition

    NASA Astrophysics Data System (ADS)

    Fiorini, Mauro; La Palombara, Nicola; Stringhetti, Luca; Canestrari, Rodolfo; Catalano, Osvaldo; Giro, Enrico; Leto, Giuseppe; Maccarone, Maria Concetta; Pareschi, Giovanni; Tosti, Gino; Vercellone, Stefano

    2014-08-01

    ASTRI is a flagship project of the Italian Ministry of Education, University and Research, which aims to develop an endto- end prototype of one of the three types of telescopes to be part of the Cherenkov Telescope Array (CTA), an observatory which will be the main representative of the next generation of Imaging Atmospheric Cherenkov Telescopes. The ASTRI project, led by the Italian National Institute of Astrophysics (INAF), has proposed an original design for the Small Size Telescope, which is aimed to explore the uppermost end of the Very High Energy domain up to about few hundreds of TeV with unprecedented sensitivity, angular resolution and imaging quality. It is characterized by challenging and innovative technological solutions which will be adopted for the first time in a Cherenkov telescope: a dual-mirror Schwarzschild-Couder configuration, a modular, light and compact camera based on silicon photomultipliers, and a front-end electronic based on a specifically designed ASIC. The end-to-end project is also including all the data-analysis software and the data archive. In this paper we describe the process followed to derive the ASTRI specifications from the CTA general requirements, a process which had to take into proper account the impact on the telescope design of the different types of the CTA requirements (performance, environment, reliability-availability-maintenance, etc.). We also describe the strategy adopted to perform the specification verification, which will be based on different methods (inspection, analysis, certification, and test) in order to demonstrate the telescope compliance with the CTA requirements. Finally we describe the integration planning of the prototype assemblies (structure, mirrors, camera, control software, auxiliary items) and the test planning of the end-to-end telescope. The approach followed by the ASTRI project is to have all the information needed to report the verification process along all project stages in a single

  15. Cherenkov Video Imaging Allows for the First Visualization of Radiation Therapy in Real Time

    SciTech Connect

    Jarvis, Lesley A.; Zhang, Rongxiao; Gladstone, David J.; Jiang, Shudong; Hitchcock, Whitney; Friedman, Oscar D.; Glaser, Adam K.; Jermyn, Michael; Pogue, Brian W.

    2014-07-01

    Purpose: To determine whether Cherenkov light imaging can visualize radiation therapy in real time during breast radiation therapy. Methods and Materials: An intensified charge-coupled device (CCD) camera was synchronized to the 3.25-μs radiation pulses of the clinical linear accelerator with the intensifier set × 100. Cherenkov images were acquired continuously (2.8 frames/s) during fractionated whole breast irradiation with each frame an accumulation of 100 radiation pulses (approximately 5 monitor units). Results: The first patient images ever created are used to illustrate that Cherenkov emission can be visualized as a video during conditions typical for breast radiation therapy, even with complex treatment plans, mixed energies, and modulated treatment fields. Images were generated correlating to the superficial dose received by the patient and potentially the location of the resulting skin reactions. Major blood vessels are visible in the image, providing the potential to use these as biological landmarks for improved geometric accuracy. The potential for this system to detect radiation therapy misadministrations, which can result from hardware malfunction or patient positioning setup errors during individual fractions, is shown. Conclusions: Cherenkoscopy is a unique method for visualizing surface dose resulting in real-time quality control. We propose that this system could detect radiation therapy errors in everyday clinical practice at a time when these errors can be corrected to result in improved safety and quality of radiation therapy.

  16. Evaluation of Multi-Anode Photomultipliers for the CLAS12 Ring-Imaging Cherenkov Detector

    NASA Astrophysics Data System (ADS)

    Samuel, Jenna

    2015-04-01

    Thomas Jefferson National Accelerator Facility has recently upgraded its Continuous Electron Beam Accelerator Facility (CEBAF) Large Acceptance Spectrometer (CLAS12) to provide a comprehensive study of the complex internal structure and dynamics of the nucleon. The upgrade includes new detectors such as the Ring Imaging Cherenkov detector (RICH). The RICH will use multi-anode photomultipliers (MAPMTs) for the detection of Cherenkov photons. Our study compared two models of Hamamatsu MAPMTs (H8500 and H12700) under consideration for the CLAS12 RICH in terms of their single photoelectron (SPE) peak, dark current, and crosstalk. The MAPMTs were tested inside a light-tight box, using a low intensity laser to simulate single photoelectron events similar to Cherenkov radiation. The H12700's SPE peaks were on average 78% the width of the H8500's peaks. For both models, the probability of dark current was on the order of 10-4. The probability of crosstalk for H8500s was 1.6 to 2.7 times that for H12700s. The H12700s were deemed better because they had negligible crosstalk and dark current while providing a narrower peak for single photoelectron events. Thomas Jefferson National Accelerator Facility, Science Undergraduate Laboratory Internship.

  17. A nuclear fuel verification system using digital imaging of Cherenkov light

    NASA Astrophysics Data System (ADS)

    Michael Attas, E.; Burton, Gordon R.; Dennis Chen, J.; Young, Gary J.; Hildingsson, Lars; Trepte, Oliver

    1997-02-01

    An UV-sensitive scientific CCD camera has been tested at a power reactor facility to image the faint Cherenkov light from irradiated nuclear fuel. The instrument mates custom optical components (lens, UV-pass filter) to a commercial scientific camera (Astrocam 4100) with a coated frame-transfer CCD chip (EEV 37-10) to produce 12-bit images of 512 × 512 pixels at several frames per second. A 250-mm {f}/{2.6} catadioptric lens has been designed with transmissive optics optimized for this application, incorporating colour correction for viewing through 10 m of water. The filter has an average transmission of 80% from 280 to 320 nm, with visible-light transmission of less than 0.03% from 365 to 780 nm to block artificial lighting in the fuel bay. Measurements were made with this instrument at the Ringhals Nuclear Power Plant, and the CLAB fuel storage facility in Sweden. Both fuel and non-fuel assemblies of boiling-water reactor (BWR) type were studied. Performance is superior to that of the earlier Cherenkov viewing devices (CVDs) based on image intensifier tubes. Increased sensitivity extends the range of the Cherenkov verification technique to fuel with older discharge dates. Increased resolution allows fine details of the fuel to be examined for higher-confidence safeguards verification. Sample digital images are presented, and the advantages to irradiated-fuel verification of image quantitation, storage, transmission, and processing are discussed.

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

    NASA Astrophysics Data System (ADS)

    Rose, P. B.; Erickson, A. S.

    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 11B(d,n-γ)12C 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 232Th, show that calibration is possible as long as the energies of photons of interest are distinct.

  19. Electron beam excitation of a CSRR loaded waveguide for Cherenkov radiation

    NASA Astrophysics Data System (ADS)

    Sharples, Emmy; Letizia, Rosa

    2015-09-01

    A novel metamaterial structure is presented for applications as a backward propagating Cherenkov source or Cherenkov detector. The structure comprises of a complementary split ring resonator (CSRR) metasurface loaded waveguide, which exhibits left handed behaviour between 5-6 GHz. When the left handed, TM-like mode couples with an incident electron beam, backward propagating Cherenkov radiation is observed. The structure is suitable for beam-based applications, exhibiting strong beam coupling parameters and significant excitation of longitudinal wakefields. Three dimensional particle in cell simulations are performed to identify a suitable beam for operation. High and low energy beams, with different bunch dimensions from the literature, are considered and compared to investigate the nature of the beam-wave interaction this structure can support, and to identify any required modification before beam tests can be performed. This structure can lead to new solutions for non-destructive beam diagnostics, wakefield acceleration and backward wave oscillators which can potentially be scaled to higher frequency ranges.

  20. Cherenkov radiation imaging of beta emitters: in vitro and in vivo results

    NASA Astrophysics Data System (ADS)

    Spinelli, Antonello E.; Boschi, Federico; D'Ambrosio, Daniela; Calderan, Laura; Marengo, Mario; Fenzi, Alberto; Menegazzi, Marta; Sbarbati, Andrea; Del Vecchio, Antonella; Calandrino, Riccardo

    2011-08-01

    The main purpose of this work was to investigate both in vitro and in vivo Cherenkov radiation (CR) emission coming from 18F and 32P. The main difference between 18F and 32P is mainly the number of the emitted light photons, more precisely the same activity of 32P emits more CR photons with respect to 18F. In vitro results obtained by comparing beta counter measurements with photons average radiance showed that Cherenkov luminescence imaging (CLI) allows quantitative tracer activity measurements. In order to investigate in vivo the CLI approach, we studied an experimental xenograft tumor model of mammary carcinoma (BB1 tumor cells). Cherenkov in vivo dynamic whole body images of tumor bearing mice were acquired and the tumor tissue time activity curves reflected the well-known physiological accumulation of 18F-FDG in malignant tissues with respect to normal tissues. The results presented here show that it is possible to use conventional optical imaging devices for in vitro or in vivo study of beta emitters.

  1. Cherenkov radiation fluence estimates in tissue for molecular imaging and therapy applications

    NASA Astrophysics Data System (ADS)

    Glaser, Adam K.; Zhang, Rongxiao; Andreozzi, Jacqueline; Gladstone, David; Pogue, Brian

    2016-03-01

    Cherenkov radiation has emerged as a novel source of light with a number of applications in the biomedical sciences. It's unique properties, including its broadband emission spectrum, spectral weighting in the ultraviolet and blue wavebands, and local generation of light within a given tissue have made it an attractive source of light for techniques ranging from widefield imaging to oximetry and phototherapy. To help guide the future development of this field in the context of molecular imaging, quantitative estimates of the light fluence rates of Cherenkov radiation from a number of radionuclide and external radiotherapy beams in tissue was explored for the first time. Using Monte Carlo simulations, these values were found to be on the order of 0.1 - 1 nW/cm2 per MBq/g for radionuclides and 1 - 10 μW/cm2 per Gy/sec for external radiotherapy beams, dependent on the given waveband and optical properties. For phototherapy applications, the total light fluence was found to be on the order of nJ/cm2 for radionuclides, and mJ/cm2 for radiotherapy beams. To validate these findings, experimental validation was completed with an MV x-ray photon beam incident onto a tissue phantom, confirming the magnitudes of the simulation values. The results indicate that diagnostic potential is reasonable for Cherenkov excitation of molecular probes, but phototherapy may remain elusive at these relatively low fluence values.

  2. Searches for dark matter subhaloes with wide-field Cherenkov telescope surveys

    SciTech Connect

    Brun, Pierre; Moulin, Emmanuel; Glicenstein, Jean-Francois; Diemand, Juerg

    2011-01-01

    The presence of substructures in dark matter haloes is an unavoidable consequence of the cold dark matter paradigm. Indirect signals from these objects have been extensively searched for with cosmic rays and {gamma} rays. At first sight, Cherenkov telescopes seem not very well suited for such searches, due to their small fields of view and the random nature of the possible dark matter substructure positions in the sky. However, with long enough exposure and an adequate observation strategy, the very good sensitivity of this experimental technique allows us to constrain particle dark matter models. We confront here the sensitivity map of the HESS experiment built out of their Galactic scan survey to the state-of-the-art cosmological N-body simulation Via Lactea II. We obtain competitive constraints on the annihilation cross section, at the level of 10{sup -24}-10{sup -23} cm{sup 3} s{sup -1}. The results are extrapolated to the future Cherenkov Telescope Array, in the cases of a Galactic plane survey and of an even wider extragalactic survey. In the latter case, it is shown that the sensitivity of the Cherenkov Telescope Array will be sufficient to reach the most natural particle dark matter models.

  3. Camera selection for real-time in vivo radiation treatment verification systems using Cherenkov imaging

    SciTech Connect

    Andreozzi, Jacqueline M. Glaser, Adam K.; Zhang, Rongxiao; Jarvis, Lesley A.; Gladstone, David J.; Pogue, Brian W.

    2015-02-15

    Purpose: To identify achievable camera performance and hardware needs in a clinical Cherenkov imaging system for real-time, in vivo monitoring of the surface beam profile on patients, as novel visual information, documentation, and possible treatment verification for clinicians. Methods: Complementary metal-oxide-semiconductor (CMOS), charge-coupled device (CCD), intensified charge-coupled device (ICCD), and electron multiplying-intensified charge coupled device (EM-ICCD) cameras were investigated to determine Cherenkov imaging performance in a clinical radiotherapy setting, with one emphasis on the maximum supportable frame rate. Where possible, the image intensifier was synchronized using a pulse signal from the Linac in order to image with room lighting conditions comparable to patient treatment scenarios. A solid water phantom irradiated with a 6 MV photon beam was imaged by the cameras to evaluate the maximum frame rate for adequate Cherenkov detection. Adequate detection was defined as an average electron count in the background-subtracted Cherenkov image region of interest in excess of 0.5% (327 counts) of the 16-bit maximum electron count value. Additionally, an ICCD and an EM-ICCD were each used clinically to image two patients undergoing whole-breast radiotherapy to compare clinical advantages and limitations of each system. Results: Intensifier-coupled cameras were required for imaging Cherenkov emission on the phantom surface with ambient room lighting; standalone CMOS and CCD cameras were not viable. The EM-ICCD was able to collect images from a single Linac pulse delivering less than 0.05 cGy of dose at 30 frames/s (fps) and pixel resolution of 512 × 512, compared to an ICCD which was limited to 4.7 fps at 1024 × 1024 resolution. An intensifier with higher quantum efficiency at the entrance photocathode in the red wavelengths [30% quantum efficiency (QE) vs previous 19%] promises at least 8.6 fps at a resolution of 1024 × 1024 and lower monetary

  4. Camera selection for real-time in vivo radiation treatment verification systems using Cherenkov imaging

    PubMed Central

    Andreozzi, Jacqueline M.; Zhang, Rongxiao; Glaser, Adam K.; Jarvis, Lesley A.; Pogue, Brian W.; Gladstone, David J.

    2015-01-01

    Purpose: To identify achievable camera performance and hardware needs in a clinical Cherenkov imaging system for real-time, in vivo monitoring of the surface beam profile on patients, as novel visual information, documentation, and possible treatment verification for clinicians. Methods: Complementary metal-oxide-semiconductor (CMOS), charge-coupled device (CCD), intensified charge-coupled device (ICCD), and electron multiplying-intensified charge coupled device (EM-ICCD) cameras were investigated to determine Cherenkov imaging performance in a clinical radiotherapy setting, with one emphasis on the maximum supportable frame rate. Where possible, the image intensifier was synchronized using a pulse signal from the Linac in order to image with room lighting conditions comparable to patient treatment scenarios. A solid water phantom irradiated with a 6 MV photon beam was imaged by the cameras to evaluate the maximum frame rate for adequate Cherenkov detection. Adequate detection was defined as an average electron count in the background-subtracted Cherenkov image region of interest in excess of 0.5% (327 counts) of the 16-bit maximum electron count value. Additionally, an ICCD and an EM-ICCD were each used clinically to image two patients undergoing whole-breast radiotherapy to compare clinical advantages and limitations of each system. Results: Intensifier-coupled cameras were required for imaging Cherenkov emission on the phantom surface with ambient room lighting; standalone CMOS and CCD cameras were not viable. The EM-ICCD was able to collect images from a single Linac pulse delivering less than 0.05 cGy of dose at 30 frames/s (fps) and pixel resolution of 512 × 512, compared to an ICCD which was limited to 4.7 fps at 1024 × 1024 resolution. An intensifier with higher quantum efficiency at the entrance photocathode in the red wavelengths [30% quantum efficiency (QE) vs previous 19%] promises at least 8.6 fps at a resolution of 1024 × 1024 and lower monetary

  5. Jovian atmospheres

    SciTech Connect

    Allison, M.; Travis, L.D.

    1986-10-01

    A conference on the atmosphere of Jupiter produced papers in the areas of thermal and ortho-para hydrogen structure, clouds and chemistry, atmospheric structure, global dynamics, synoptic features and processes, atmospheric dynamics, and future spaceflight opportunities. A session on the atmospheres of Uranus and Neptune was included, and the atmosphere of Saturn was discussed in several papers.

  6. Study of the shower maximum depth by the method of detection of the EAS Cerenkov light pulse shape

    NASA Technical Reports Server (NTRS)

    Aliev, N.; Kakhkharov, M.; Khakimov, N.; Makhmudov, B. M.; Rakhimova, N.; Tashpulatov, R.; Khristiansen, G. B.; Prosin, V. V.; Alimov, T.; Zhukov, V. Y.

    1985-01-01

    The results of processing the data on the shape of the EAS Cerenkov light pulses recorded by the extensive air showers (EAS) array are presented. The pulse FWHM is used to find the mean depth of EAS maximum.

  7. Project of the URAN array for registration of atmospheric neutrons

    NASA Astrophysics Data System (ADS)

    Gromushkin, D. M.; Barbashina, N. S.; Bogdanov, F. A.; Kokoulin, R. P.; Ovchinnikov, V. V.; Petrukhin, A. A.; Stenkin, Yu V.; Khokhlov, S. S.; Shulzhenko, I. A.; Yashin, I. I.

    2016-02-01

    The project of a new setup is directed at the registration of atmospheric neutrons (URAN) generated by hadronic component of extensive air showers (EAS). The setup includes 72 en-detector which simultaneously register two major EAS components: electromagnetic by the group passage of charged particles and hadron component by the thermal neutrons. The neutrons and charged particles are detected using a specialized scintillation composition made of granulated alloy of crystals based on the ZnS(Ag) powder with an admixture of B2O3.

  8. Observation of EAS using a large water tank

    NASA Technical Reports Server (NTRS)

    Inoue, K.; Sakuyama, H.; Suzuki, N.; Suzuki, T.

    1985-01-01

    Using a large water tank (30 m in diameter, 4.5 m in depth) transition of extensive air showers (EAS) was investigated at Taro (200 m above sea level). There are set 150,0.4 sq m proportional counters on the bottom of the water tank. A conventional EAS array of 25 plastic scintillation detectors was arranged within several tens meter from the water tank. A proportional counter (10x10x200 cc x2) is made of a square shaped pipe of iron. Tungsten wire (100 mu m phi) is stretched tight in the center of the counter. A gas mixture of 90% argon and 10% methane is used at 760 mmHg. About 3000 EAS were obtained through 1 m of water since 1984.

  9. Observation of EAS using a large water tank

    NASA Astrophysics Data System (ADS)

    Inoue, K.; Sakuyama, H.; Suzuki, N.; Suzuki, T.

    1985-08-01

    Using a large water tank (30 m in diameter, 4.5 m in depth) transition of extensive air showers (EAS) was investigated at Taro (200 m above sea level). There are set 150,0.4 sq m proportional counters on the bottom of the water tank. A conventional EAS array of 25 plastic scintillation detectors was arranged within several tens meter from the water tank. A proportional counter (10x10x200 cc x2) is made of a square shaped pipe of iron. Tungsten wire (100 mu m phi) is stretched tight in the center of the counter. A gas mixture of 90% argon and 10% methane is used at 760 mmHg. About 3000 EAS were obtained through 1 m of water since 1984.

  10. Time distribution of EAS with E>10/sup 14/ eV

    SciTech Connect

    CHEN Ying-xuan; HE Chang-xiao; XIAO Qian-yi; WANG Li-xiang

    1986-01-01

    We have observed the arrival times of EAS initiated by cosmic rays of E>10/sup 14/ eV using the EAS array in Beijing. The distribution of arrival time intervals of EAS with E>2.6 x 10/sup 14/ eV is considerably higher than the exponential distribution in the region of time intervals t<21 second. It is suggested that a time correlation component is probably present in the EAS events.

  11. E.A. Gilbert Generating Unit, Maysville, Kentucky

    SciTech Connect

    Wicker, K.

    2005-08-01

    The new, 368-MW E.A. Gilbert Generating Unit at the H.L. Spurlock Power Station in Maysville isn't just the cleanest coal-burning plant in Kentucky. Thanks to its circulating liquidized bed boiler from Alstom, it is one of the cleanest in the US. The boiler's ability to burn a wide variety of coals and even pet coke, biomass, or tire-derived fuels - also was a factor in Power's decision to name E.A. Gilbert a Top Plant of 2005. 3 figs., 2 tabs.

  12. Design of Cherenkov bars for the optical part of the time-of-flight detector in Geant4.

    PubMed

    Nozka, L; Brandt, A; Rijssenbeek, M; Sykora, T; Hoffman, T; Griffiths, J; Steffens, J; Hamal, P; Chytka, L; Hrabovsky, M

    2014-11-17

    We present the results of studies devoted to the development and optimization of the optical part of a high precision time-of-flight (TOF) detector for the Large Hadron Collider (LHC). This work was motivated by a proposal to use such a detector in conjunction with a silicon detector to tag and measure protons from interactions of the type p + p → p + X + p, where the two outgoing protons are scattered in the very forward directions. The fast timing detector uses fused silica (quartz) bars that emit Cherenkov radiation as a relativistic particle passes through and the emitted Cherenkov photons are detected by, for instance, a micro-channel plate multi-anode Photomultiplier Tube (MCP-PMT). Several possible designs are implemented in Geant4 and studied for timing optimization as a function of the arrival time, and the number of Cherenkov photons reaching the photo-sensor. PMID:25402137

  13. Maximal Cherenkov γ-radiation on Fermi-surface of compact stars

    SciTech Connect

    Akbari-Moghanjoughi, M.

    2014-05-15

    The quantum magnetohydrodynamic model is employed in this paper to study the extraordinary (XO) elliptically polarized electromagnetic wave dispersion in quantum plasmas with spin-1/2 magnetization and relativistic degeneracy effects, considering also the electron-exchange and quantum diffraction of electrons. From the lower and upper calculated XO-modes, it is observed that, for electrons on the surface of the Fermi-sphere, the lower XO-mode can excite the Cherenkov radiation by crossing the Fermi-line, with some proper conditions depending on the values of independent plasma parameters, such as the relativistic-degeneracy, the atomic-number of constituent ions, and the magnetic field strength. Particularly, a lower electron number-density and Cherenkov radiation frequency limits are found to exist, for instance, for given values of the plasma ions atomic-number and the magnetic field strength below which the radiation can not be excited by the electrons on the Fermi-surface. This lower density limit increases by decrease in the atomic-number but decreases with decrease in the strength of the ambient magnetic field. It is remarkable that in this research it is discovered that the maximal Cherenkov-radiation per unit-length (the energy radiated by superluminal electrons traveling through the dielectric medium) coincides with the plasma number-densities, which is present in compact stars with the maximal radiation frequency lying in the gamma-ray spectrum. Current study can provide an important plasma diagnostic tool for a wide plasma density range, be it the solid density, the warm dense matter, the inertial confined or the astrophysical compact plasmas and may reveal an important cooling mechanism for white dwarfs. Current findings may also answer the fundamental astrophysical question on the mysterious origin of intense cosmic gamma-ray emissions.

  14. Charged particle tracking in a water Cherenkov optical time projection chamber

    NASA Astrophysics Data System (ADS)

    Oberla, Eric

    A first experimental test of tracking relativistic charged particles by `drifting' Cherenkov photons in a water-based optical time-projection chamber (OTPC) at the Fermilab Test Beam Facility is described. By measuring the relative time-of-arrival and (z,φ) coordinates of individual photons, we show spatial and angular resolutions on the charged particle track of 15 mm and 60 mrad, respectively, over a track length of 40 cm. The OTPC consists of a 77 cm long, 40~kg cylindrical water mass instrumented with a combination of commercial 5.1x 5.1 cm2 micro-channel plate photo-multiplier tubes (MCP-PMT) and 6.7 x6.7 cm2 mirrors. Using planar MCP-PMTs with an anode of 50O microstrips, it is feasible to resolve the time-of-arrival of a single photon to ≤100 ps and its detected position to a few~mm. The MCP-PMTs are installed in two columns along the OTPC cylinder in a small-angle stereo configuration. A mirror is mounted opposing each MCP-PMT on the far side of the detector cylinder, which effectively doubles the photo-detection efficiency and provides a time-resolved image of the Cherenkov light on the opposing wall. A 180-channel data acquisition system digitizes the MCP-PMT signals using the PSEC4 waveform sampling chip operating at 10 Gigasamples-per-second. The detector was installed on the Fermilab MCenter test-beam in a location where the primary flux is multi-GeV muons. Approximately 80 Cherenkov photons are detected for a through-going muon track in an event duration of 2 ns.

  15. Design and Fabrication of Cherenkov Counters for the Detection of SNM

    NASA Astrophysics Data System (ADS)

    Erickson, Anna S.; Galaitsis, Anthony; Lanza, Richard; Hynes, Michael; Bernstein, Adam; Blackburn, Brandon

    2011-12-01

    The need for large-size detectors for long-range active interrogation (AI) detection of SNM has generated interest in water-based detector technologies. Water Cherenkov Detectors (WCD) were selected for this research because of their transportability, scalability, and an inherent energy threshold. The detector design and analysis was completed using the Geant4 toolkit. It was demonstrated both computationally and experimentally that it is possible to use WCD to detect and characterize gamma rays. Absolute efficiency of the detector (with no energy cuts applied) was determined to be around 30% for a 60Co source.

  16. Cherenkov radiation of a Josephson vortex moving in a sandwich embedded in a dielectric medium

    SciTech Connect

    Malishevskii, A. S. Silin, V. P.; Uryupin, S. A.; Uspenskii, S. G.

    2008-08-15

    A motion of a Josephson vortex in a long sandwich embedded in a dielectric medium is described. If the velocity of the vortex is greater than the velocity of light in the dielectric, terahertz-band Cherenkov radiation is generated and emitted from the lateral surface of the sandwich. The radiation loss power is determined. In the case when radiation loss is compensated for by the energy gain due to transport current, a relation between the current and the velocity of the vortex is obtained.

  17. Analogues of Vavilov-Cherenkov radiation in an array of noninteracting nanotubes

    NASA Astrophysics Data System (ADS)

    Sadykov, N. R.; Aporoski, A. V.

    2016-07-01

    We consider the mechanism for generating radiation whose source is formed by surface currents modulated in the variable z - vt in an array of noninteracting parallel nanotubes. The nanotubes are oriented perpendicular to the axis Oz, and the velocity v exceeds the velocity of light in the medium. On the qualitative level, the radiation process under study is analogous to Vavilov-Cherenkov radiation by a system of dipoles. We show that intense SHF and THz radiation can be generated using this method. We estimate the magnitude of millimetric radiation obtainable using an array of nanotubes.

  18. Comparison of Cherenkov excited fluorescence and phosphorescence molecular sensing from tissue with external beam irradiation.

    PubMed

    Lin, Huiyun; Zhang, Rongxiao; Gunn, Jason R; Esipova, Tatiana V; Vinogradov, Sergei; Gladstone, David J; Jarvis, Lesley A; Pogue, Brian W

    2016-05-21

    Ionizing radiation delivered by a medical linear accelerator (LINAC) generates Cherenkov emission within the treated tissue. A fraction of this light, in the 600-900 nm wavelength region, propagates through centimeters of tissue and can be used to excite optical probes in vivo, enabling molecular sensing of tissue analytes. The success of isolating the emission signal from this Cherenkov excitation background is dependent on key factors such as: (i) the Stokes shift of the probe spectra; (ii) the excited state lifetime; (iii) the probe concentration; (iv) the depth below the tissue surface; and (v) the radiation dose used. Previous studies have exclusively focused on imaging phosphorescent dyes, rather than fluorescent dyes. However there are only a few biologically important phosphorescent dyes and yet in comparison there are thousands of biologically relevant fluorescent dyes. So in this study the focus was a study of efficacy of Cherenkov-excited luminescence using fluorescent commercial near-infrared probes, IRDye 680RD, IRDye 700DX, and IRDye 800CW, and comparing them to the well characterized phosphorescent probe Oxyphor PtG4, an oxygen sensitive dye. Each probe was excited by Cherenkov light from a 6 MV external radiation beam, and measured in continuous wave or time-gated modes. The detection was performed by spectrally resolving the luminescence signals, and measuring them with spectrometer-based separation on an ICCD detector. The results demonstrate that IRDye 700DX and PtG4 allowed for the maximal signal to noise ratio. In the case of the phosphorescent probe, PtG4, with emission decays on the microsecond (μs) time scale, time-gated acquisition was possible, and it allowed for higher efficacy in terms of the probe concentration and detection depth. Phantoms containing the probe at 5 mm depth could be detected at concentrations down to the nanoMolar range, and at depths into the tissue simulating phantom near 3 cm. In vivo studies showed that 5

  19. The fluid systems for the SLD Cherenkov ring imaging detector. [01

    SciTech Connect

    Abe, K.; Hasegawa, K.; Hasegawa, Y.; Iwasaki, Y.; Suekane, F.; Yuta, H. . Dept. of Physics); Antilogus, P.; Aston, D.; Bienz, T.; Bird, F.; Dasu, S.; Dolinsky, S.; Dunwoodie, W.; Hallewell, G.; Kawahara, H.; Kwon, Y.; Leith, D.W.G.S.; McCulloch, M.; McShurley, D.; Mueller, G.; Muller, D.; Nagamine, T.; Pavel, T.J.; Peterson, H.; Ratcliff, B.; Reif, R.; Rensing, P.; Schultz, D.; Shapiro, S.; Shaw,

    1992-10-01

    We describe the design and operation of the fluid delivery, monitor and control systems for the SLD barrel Cherenkov Ring Imaging Detector (CRID). The systems deliver drift gas (C[sub 2]H[sub 6] + TMAE), radiator gas (C[sub 5]F[sub 12] + N[sub 2]) and radiator liquid (C[sub 6]F[sub 14]). Measured critical quantities such as electron lifetime in the drift gas and ultra-violet (UV) transparencies of the radiator fluids, together with the operational experience, are also reported.

  20. Characterizing Scitillation and Cherenkov Light Yield in Water-Based Liquid Scintillators

    NASA Astrophysics Data System (ADS)

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

    2016-03-01

    The recent development of Water-based Liquid Scintillator (WbLS) has made it possible to produce scintillating materials with highly tunable light yields and excellent optical clarity. This allows for a straightforward combination of the directional properties of Cherenkov light with the greater energy resolution afforded by the typically brighter scintillation light, which lends itself well to a broad program of neutrino physics. Here we explore the light yields and optical properties of WbLS materials in development for Theia (formerly ASDC) as measured in our benchtop Theia R&D at Berkeley Lab and extrapolate to larger detectors.

  1. TORCH - Cherenkov and Time-of-Flight PID Detector for the LHCb Upgrade at CERN

    NASA Astrophysics Data System (ADS)

    Föhl, K.; Brook, N.; Castillo García, L.; Conneely, T.; Cussans, D.; Forty, R.; Frei, C.; Gao, R.; Gys, T.; Harnew, N.; Milnes, J.; Piedigrossi, D.; Rademacker, J.; Ros Garcì a, A.; van Dijk, M.

    2016-05-01

    TORCH is a large-area precision time-of-flight detector, based on Cherenkov light production and propagation in a quartz radiator plate, which is read out at its edges. TORCH is proposed for the LHCb experiment at CERN to provide positive particle identification for kaons, and is currently in the Research-and-Development phase. A brief overview of the micro-channel plate photon sensor development, the custom-made electronics, and an introduction to the current test beam activities is given. Optical readout solutions are presented for the potential use of BaBar DIRC bar boxes as part of the TORCH configuration in LHCb.

  2. Cherenkov Detector For Measurements Of Fast Electrons In CASTOR-Tokamak

    SciTech Connect

    Jakubowski, L.; Sadowski, M. J.; Stanislawski, J.; Malinowski, K.; Zebrowski, J.; Jakubowski, M.; Weinzettl, V.; Stockel, J.; Vacha, M.; Peterka, M.

    2008-04-07

    The paper reports on capabilities of an improved version of the Cherenkov detector designed for measurements of fast electrons. The described technique enables the identification of electron beams, the measurements of their temporal characteristics, as well as the estimation of their spatial properties to be performed. Results obtained in the last experimental campaign with the CASTOR facility show good measuring capabilities of such a detection system. The radial distributions of fast-electron streams at different plasma densities, as well as the electron fluency dependences on discharge currents and toroidal magnetic fields are also presented.

  3. Cherenkov luminescence imaging in transparent media and the imaging of thin or shallow sources

    PubMed Central

    Komarov, Sergey; Zhou, Dong; Liu, Yongjian; Tai, Yuan-Chuan

    2015-01-01

    Abstract. In this work, we demonstrated the possibility of high spatial resolution Cherenkov luminescence imaging (CLI) for objects in transparent media. We also demonstrated the possibility of the CLI of thin opaque objects using optical transducers. Results demonstrate that submillimeter resolution CLI is achievable for beta-emitting radionuclides, including Br76 that emits positrons of very high energy. The imaging of beta-emitters through scintillation detectors exhibits lower resolution when compared to CLI of the same sources. The application of optical transducers for the CLI was demonstrated using plants labeled with CO112 and phantoms containing beta-emitters. PMID:25789422

  4. Comparison of Cherenkov excited fluorescence and phosphorescence molecular sensing from tissue with external beam irradiation

    NASA Astrophysics Data System (ADS)

    Lin, Huiyun; Zhang, Rongxiao; Gunn, Jason R.; Esipova, Tatiana V.; Vinogradov, Sergei; Gladstone, David J.; Jarvis, Lesley A.; Pogue, Brian W.

    2016-05-01

    Ionizing radiation delivered by a medical linear accelerator (LINAC) generates Cherenkov emission within the treated tissue. A fraction of this light, in the 600–900 nm wavelength region, propagates through centimeters of tissue and can be used to excite optical probes in vivo, enabling molecular sensing of tissue analytes. The success of isolating the emission signal from this Cherenkov excitation background is dependent on key factors such as: (i) the Stokes shift of the probe spectra; (ii) the excited state lifetime; (iii) the probe concentration; (iv) the depth below the tissue surface; and (v) the radiation dose used. Previous studies have exclusively focused on imaging phosphorescent dyes, rather than fluorescent dyes. However there are only a few biologically important phosphorescent dyes and yet in comparison there are thousands of biologically relevant fluorescent dyes. So in this study the focus was a study of efficacy of Cherenkov-excited luminescence using fluorescent commercial near-infrared probes, IRDye 680RD, IRDye 700DX, and IRDye 800CW, and comparing them to the well characterized phosphorescent probe Oxyphor PtG4, an oxygen sensitive dye. Each probe was excited by Cherenkov light from a 6 MV external radiation beam, and measured in continuous wave or time-gated modes. The detection was performed by spectrally resolving the luminescence signals, and measuring them with spectrometer-based separation on an ICCD detector. The results demonstrate that IRDye 700DX and PtG4 allowed for the maximal signal to noise ratio. In the case of the phosphorescent probe, PtG4, with emission decays on the microsecond (μs) time scale, time-gated acquisition was possible, and it allowed for higher efficacy in terms of the probe concentration and detection depth. Phantoms containing the probe at 5 mm depth could be detected at concentrations down to the nanoMolar range, and at depths into the tissue simulating phantom near 3 cm. In vivo studies showed that 5

  5. Design and Fabrication of Cherenkov Counters for the Detection of SNM

    SciTech Connect

    Erickson, Anna S.; Lanza, Richard; Galaitsis, Anthony; Hynes, Michael; Blackburn, Brandon; Bernstein, Adam

    2011-12-13

    The need for large-size detectors for long-range active interrogation (AI) detection of SNM has generated interest in water-based detector technologies. Water Cherenkov Detectors (WCD) were selected for this research because of their transportability, scalability, and an inherent energy threshold. The detector design and analysis was completed using the Geant4 toolkit. It was demonstrated both computationally and experimentally that it is possible to use WCD to detect and characterize gamma rays. Absolute efficiency of the detector (with no energy cuts applied) was determined to be around 30% for a {sup 60}Co source.

  6. 77 FR 1676 - EasTrans, LLC; Notice Granting Extension of Time

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-01-11

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF ENERGY Federal Energy Regulatory Commission EasTrans, LLC; Notice Granting Extension of Time On December 16, 2011, Eas... an extension of time for EasTrans to file its section 284.123 rate petition is granted to...

  7. 47 CFR 11.56 - EAS Participants receive CAP-formatted alerts.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false EAS Participants receive CAP-formatted alerts. 11.56 Section 11.56 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Emergency Operations § 11.56 EAS Participants receive CAP-formatted alerts....

  8. 47 CFR 11.19 - EAS Non-participating National Authorization Letter.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false EAS Non-participating National Authorization Letter. 11.19 Section 11.19 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) General § 11.19 EAS Non-participating National Authorization Letter. This...

  9. 47 CFR 11.45 - Prohibition of false or deceptive EAS transmissions.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 1 2010-10-01 2010-10-01 false Prohibition of false or deceptive EAS transmissions. 11.45 Section 11.45 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Organization § 11.45 Prohibition of false or deceptive EAS transmissions. No person...

  10. 47 CFR 76.1711 - Emergency alert system (EAS) tests and activation.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 4 2010-10-01 2010-10-01 false Emergency alert system (EAS) tests and... § 76.1711 Emergency alert system (EAS) tests and activation. Every cable system of 1,000 or more subscribers shall keep a record of each test and activation of the Emergency Alert System (EAS)...

  11. 47 CFR 11.51 - EAS code and Attention Signal Transmission requirements.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false EAS code and Attention Signal Transmission requirements. 11.51 Section 11.51 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Emergency Operations § 11.51 EAS code and Attention Signal Transmission requirements. (a) Analog and digital broadcast...

  12. 47 CFR 11.51 - EAS code and Attention Signal Transmission requirements.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false EAS code and Attention Signal Transmission requirements. 11.51 Section 11.51 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Emergency Operations § 11.51 EAS code and Attention Signal Transmission requirements. (a) Analog and digital broadcast...

  13. 47 CFR 11.54 - EAS operation during a National Level emergency.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false EAS operation during a National Level emergency. 11.54 Section 11.54 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Emergency Operations § 11.54 EAS operation during a National Level emergency. (a) Immediately upon receipt of an EAN message,...

  14. 47 CFR 11.51 - EAS code and Attention Signal Transmission requirements.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false EAS code and Attention Signal Transmission requirements. 11.51 Section 11.51 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Emergency Operations § 11.51 EAS code and Attention Signal Transmission requirements. (a) Analog and digital broadcast...

  15. 47 CFR 11.54 - EAS operation during a National Level emergency.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false EAS operation during a National Level emergency. 11.54 Section 11.54 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Emergency Operations § 11.54 EAS operation during a National Level emergency. (a) Immediately upon receipt of an EAN message,...

  16. 47 CFR 11.56 - EAS Participants receive CAP-formatted alerts.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false EAS Participants receive CAP-formatted alerts. 11.56 Section 11.56 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Emergency Operations § 11.56 EAS Participants receive CAP-formatted alerts....

  17. 47 CFR 11.45 - Prohibition of false or deceptive EAS transmissions.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false Prohibition of false or deceptive EAS transmissions. 11.45 Section 11.45 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Organization § 11.45 Prohibition of false or deceptive EAS transmissions. No person...

  18. 47 CFR 76.1711 - Emergency alert system (EAS) tests and activation.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 4 2011-10-01 2011-10-01 false Emergency alert system (EAS) tests and... § 76.1711 Emergency alert system (EAS) tests and activation. Every cable system of 1,000 or more subscribers shall keep a record of each test and activation of the Emergency Alert System (EAS)...

  19. 47 CFR 76.1711 - Emergency alert system (EAS) tests and activation.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 4 2012-10-01 2012-10-01 false Emergency alert system (EAS) tests and... § 76.1711 Emergency alert system (EAS) tests and activation. Every cable system of 1,000 or more subscribers shall keep a record of each test and activation of the Emergency Alert System (EAS)...

  20. 47 CFR 11.45 - Prohibition of false or deceptive EAS transmissions.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 1 2012-10-01 2012-10-01 false Prohibition of false or deceptive EAS transmissions. 11.45 Section 11.45 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Organization § 11.45 Prohibition of false or deceptive EAS transmissions. No person...

  1. 47 CFR 76.1711 - Emergency alert system (EAS) tests and activation.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 4 2014-10-01 2014-10-01 false Emergency alert system (EAS) tests and... § 76.1711 Emergency alert system (EAS) tests and activation. Every cable system of 1,000 or more subscribers shall keep a record of each test and activation of the Emergency Alert System (EAS)...

  2. 47 CFR 76.1711 - Emergency alert system (EAS) tests and activation.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 4 2013-10-01 2013-10-01 false Emergency alert system (EAS) tests and... § 76.1711 Emergency alert system (EAS) tests and activation. Every cable system of 1,000 or more subscribers shall keep a record of each test and activation of the Emergency Alert System (EAS)...

  3. 47 CFR 11.45 - Prohibition of false or deceptive EAS transmissions.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false Prohibition of false or deceptive EAS transmissions. 11.45 Section 11.45 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Organization § 11.45 Prohibition of false or deceptive EAS transmissions. No person...

  4. 47 CFR 11.55 - EAS operation during a State or Local Area emergency.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 1 2013-10-01 2013-10-01 false EAS operation during a State or Local Area emergency. 11.55 Section 11.55 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Emergency Operations § 11.55 EAS operation during a State or Local Area emergency. (a)...

  5. 47 CFR 11.55 - EAS operation during a State or Local Area emergency.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false EAS operation during a State or Local Area emergency. 11.55 Section 11.55 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Emergency Operations § 11.55 EAS operation during a State or Local Area emergency. (a)...

  6. 47 CFR 11.45 - Prohibition of false or deceptive EAS transmissions.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 1 2014-10-01 2014-10-01 false Prohibition of false or deceptive EAS transmissions. 11.45 Section 11.45 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) Organization § 11.45 Prohibition of false or deceptive EAS transmissions. No person...

  7. 47 CFR 11.19 - EAS Non-participating National Authorization Letter.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 1 2011-10-01 2011-10-01 false EAS Non-participating National Authorization Letter. 11.19 Section 11.19 Telecommunication FEDERAL COMMUNICATIONS COMMISSION GENERAL EMERGENCY ALERT SYSTEM (EAS) General § 11.19 EAS Non-participating National Authorization Letter. This...

  8. 76 FR 24874 - Initiation of Scoping for an Environmental Assessment (EA)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-05-03

    ... Assessment (EA) to analyze the potential environmental impacts related to the reissuance of the National.... The EA will evaluate the potential environmental impacts from the discharge of pollutants associated... authority. EPA will use the information in the EA to determine whether to prepare an Environmental...

  9. 76 FR 80366 - Availability of an Environmental Assessment (EA) and Finding of No Significant Impact (FONSI)

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-23

    ... issues and reasonable alternatives to be addressed in the EA. 76 FR 22882. The environmental review... AGENCY Availability of an Environmental Assessment (EA) and Finding of No Significant Impact (FONSI) AGENCY: Environmental Protection Agency (EPA). ACTION: Environmental Assessment (EA)/Finding of...

  10. 47 CFR 90.685 - Authorization, construction and implementation of EA licenses.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Authorization, construction and implementation..., construction and implementation of EA licenses. (a) EA licenses in the 809-824/854-869 MHz band will be issued... the construction period. (d) An EA licensee's failure to meet the population coverage requirements...

  11. The atmospheric monitoring system of the JEM-EUSO instrument

    NASA Astrophysics Data System (ADS)

    Adams, J. H.; Ahmad, S.; Albert, J.-N.; Allard, D.; Anchordoqui, L.; Andreev, V.; Anzalone, A.; Arai, Y.; Asano, K.; Ave Pernas, M.; Baragatti, P.; Barrillon, P.; Batsch, T.; Bayer, J.; Bechini, R.; Belenguer, T.; Bellotti, R.; Belov, K.; Berlind, A. A.; Bertaina, M.; Biermann, P. L.; Biktemerova, S.; Blaksley, C.; Blanc, N.; Błȩcki, J.; Blin-Bondil, S.; Blümer, J.; Bobik, P.; Bogomilov, M.; Bonamente, M.; Briggs, M. S.; Briz, S.; Bruno, A.; Cafagna, F.; Campana, D.; Capdevielle, J.-N.; Caruso, R.; Casolino, M.; Cassardo, C.; Castellinic, G.; Catalano, C.; Catalano, G.; Cellino, A.; Chikawa, M.; Christl, M. J.; Cline, D.; Connaughton, V.; Conti, L.; Cordero, G.; Crawford, H. J.; Cremonini, R.; Csorna, S.; Dagoret-Campagne, S.; de Castro, A. J.; De Donato, C.; de la Taille, C.; De Santis, C.; del Peral, L.; Dell'Oro, A.; De Simone, N.; Di Martino, M.; Distratis, G.; Dulucq, F.; Dupieux, M.; Ebersoldt, A.; Ebisuzaki, T.; Engel, R.; Falk, S.; Fang, K.; Fenu, F.; Fernández-Gómez, I.; Ferrarese, S.; Finco, D.; Flamini, M.; Fornaro, C.; Franceschi, A.; Fujimoto, J.; Fukushima, M.; Galeotti, P.; Garipov, G.; Geary, J.; Gelmini, G.; Giraudo, G.; Gonchar, M.; González Alvarado, C.; Gorodetzky, P.; Guarino, F.; Guzmán, A.; Hachisu, Y.; Harlov, B.; Haungs, A.; Hernández Carretero, J.; Higashide, K.; Ikeda, D.; Ikeda, H.; Inoue, N.; Inoue, S.; Insolia, A.; Isgrò, F.; Itow, Y.; Joven, E.; Judd, E. G.; Jung, A.; Kajino, F.; Kajino, T.; Kaneko, I.; Karadzhov, Y.; Karczmarczyk, J.; Karus, M.; Katahira, K.; Kawai, K.; Kawasaki, Y.; Keilhauer, B.; Khrenov, B. A.; Kim, J.-S.; Kim, S.-W.; Kim, S.-W.; Kleifges, M.; Klimov, P. A.; Kolev, D.; Kreykenbohm, I.; Kudela, K.; Kurihara, Y.; Kusenko, A.; Kuznetsov, E.; Lacombe, M.; Lachaud, C.; Lee, J.; Licandro, J.; Lim, H.; López, F.; Maccarone, M. C.; Mannheim, K.; Maravilla, D.; Marcelli, L.; Marini, A.; Martinez, O.; Masciantonio, G.; Mase, K.; Matev, R.; Medina-Tanco, G.; Mernik, T.; Miyamoto, H.; Miyazaki, Y.; Mizumoto, Y.; Modestino, G.; Monaco, A.; Monnier-Ragaigne, D.; Morales de los Ríos, J. A.; Moretto, C.; Morozenko, V. S.; Mot, B.; Murakami, T.; Murakami, M. Nagano; Nagata, M.; Nagataki, S.; Nakamura, T.; Napolitano, T.; Naumov, D.; Nava, R.; Neronov, A.; Nomoto, K.; Nonaka, T.; Ogawa, T.; Ogio, S.; Ohmori, H.; Olinto, A. V.; Orleański, P.; Osteria, G.; Panasyuk, M. I.; Parizot, E.; Park, I. H.; Park, H. W.; Pastircak, B.; Patzak, T.; Paul, T.; Pennypacker, C.; Perez Cano, S.; Peter, T.; Picozza, P.; Pierog, T.; Piotrowski, L. W.; Piraino, S.; Plebaniak, Z.; Pollini, A.; Prat, P.; Prévôt, G.; Prieto, H.; Putis, M.; Reardon, P.; Reyes, M.; Ricci, M.; Rodríguez, I.; Rodríguez Frías, M. D.; Ronga, F.; Roth, M.; Rothkaehl, H.; Roudil, G.; Rusinov, I.; Rybczyński, M.; Sabau, M. D.; Sáez-Cano, G.; Sagawa, H.; Saito, A.; Sakaki, N.; Sakata, M.; Salazar, H.; Sánchez, S.; Santangelo, A.; Santiago Crúz, L.; Sanz Palomino, M.; Saprykin, O.; Sarazin, F.; Sato, H.; Sato, M.; Schanz, T.; Schieler, H.; Scotti, V.; Segreto, A.; Selmane, S.; Semikoz, D.; Serra, M.; Sharakin, S.; Shibata, T.; Shimizu, H. M.; Shinozaki, K.; Shirahama, T.; Siemieniec-Oziȩbło, G.; Silva López, H. H.; Sledd, J.; Słomińska, K.; Sobey, A.; Sugiyama, T.; Supanitsky, D.; Suzuki, M.; Szabelska, B.; Szabelski, J.; Tajima, F.; Tajima, N.; Tajima, T.; Takahashi, Y.; Takami, H.; Takeda, M.; Takizawa, Y.; Tenzer, C.; Tibolla, O.; Tkachev, L.; Tokuno, H.; Tomida, T.; Tone, N.; Toscano, S.; Trillaud, F.; Tsenov, R.; Tsunesada, Y.; Tsuno, K.; Tymieniecka, T.; Uchihori, Y.; Unger, M.; Vaduvescu, O.; Valdés-Galicia, J. F.; Vallania, P.; Valore, L.; Vankova, G.; Vigorito, C.; Villaseñor, L.; von Ballmoos, P.; Wada, S.; Watanabe, J.; Watanabe, S.; Watts, J.; Weber, M.; Weiler, T. J.; Wibig, T.; Wiencke, L.; Wille, M.; Wilms, J.; Włodarczyk, Z.; Yamamoto, T.; Yamamoto, Y.; Yang, J.; Yano, H.; Yashin, I. V.; Yonetoku, D.; Yoshida, K.; Yoshida, S.; Young, R.; Zotov, M. Yu.; Zuccaro Marchi, A.

    2015-11-01

    The JEM-EUSO telescope will detect Ultra-High Energy Cosmic Rays (UHECRs) from space, detecting the UV Fluorescence Light produced by Extensive Air Showers (EAS) induced by the interaction of the cosmic rays with the earth's atmosphere. The capability to reconstruct the properties of the primary cosmic ray depends on the accurate measurement of the atmospheric conditions in the region of EAS development. The Atmospheric Monitoring (AM) system of JEM-EUSO will host a LIDAR, operating in the UV band, and an Infrared camera to monitor the cloud cover in the JEM-EUSO Field of View, in order to be sensitive to clouds with an optical depth τ ≥ 0.15 and to measure the cloud top altitude with an accuracy of 500 m and an altitude resolution of 500 m.

  12. A tunable terahertz radiation source based on a surface wave transformed into Cherenkov radiation in a subwavelength array

    NASA Astrophysics Data System (ADS)

    Zhang, Ping; Hu, Min; Zhong, Renbin; Cheng, Xiaoxing; Gong, Sen; Zhao, Tao; Liu, Shenggang

    2016-04-01

    A tunable THz radiation source based on the Cherenkov radiation mechanism is proposed. In the structure of a dielectric medium rod covered by subwavelength metal ring array, the surface wave is excited by electron bunch on the subwavelength metal ring array, and then transformed into Cherenkov radiation in the dielectric medium rod. The working frequency is determined by the intersection of the surface wave dispersion curve and electron beam line, and could be tuned by adjusting the beam energy. The source, which is compact and operable at room temperature, generates radiation with peak power from microwatts up to milliwatts.

  13. Mass composition sensitivity of combined arrays of water cherenkov and scintillation detectors in the EeV range

    NASA Astrophysics Data System (ADS)

    Gonzalez, Javier G.; Engel, Ralph; Roth, Markus

    2016-02-01

    We consider an array of scintillation detectors combined with an array of water Cherenkov detectors designed to simultaneously measure the cosmic-ray primary mass composition and energy spectrum at energies around 1EeV. In this work we investigate the sensitivity to primary mass composition of such combined arrays. The water Cherenkov detectors are arranged in a triangular grid with fixed 750m spacing and the configuration of the scintillation detectors is changed to study the impact of different configurations on the sensitivity to mass composition. We show that the performance for composition determination can be compared favorably to that of fluorescence measurements after the difference in duty cycles is considered.

  14. Cherenkov imaging during volumetric modulated arc therapy for real-time radiation beam tracking and treatment response monitoring

    NASA Astrophysics Data System (ADS)

    Andreozzi, Jacqueline M.; Zhang, Rongxiao; Glaser, Adam K.; Gladstone, David J.; Jarvis, Lesley A.; Pogue, Brian W.

    2016-03-01

    External beam radiotherapy utilizes high energy radiation to target cancer with dynamic, patient-specific treatment plans. The otherwise invisible radiation beam can be observed via the optical Cherenkov photons emitted from interaction between the high energy beam and tissue. Using a specialized camera-system, the Cherenkov emission can thus be used to track the radiation beam on the surface of the patient in real-time, even for complex cases such as volumetric modulated arc therapy (VMAT). Two patients undergoing VMAT of the head and neck were imaged and analyzed, and the viability of the system to provide clinical feedback was established.

  15. Note: Measurements of fast electrons in the TORE-SUPRA tokamak by means of modified Cherenkov-type diamond detector

    SciTech Connect

    Jakubowski, L.; Sadowski, M. J.; Zebrowski, J.; Rabinski, M.; Jakubowski, M. J.; Malinowski, K.; Mirowski, R.; Lotte, Ph.; Goniche, M.; Gunn, J.; Colledani, G.; Pascal, J.-Y.; Basiuk, V.

    2013-01-15

    The Note reports on experimental studies of ripple born fast electrons within the TORE-SUPRA facility, which were performed by means of a modified measuring head equipped with diamond detectors designed especially for recording the electron-induced Cherenkov radiation. There are presented signals produced by fast electrons in the TORE-SUPRA machine, which were recorded during two experimental campaigns performed in 2010. Shapes of these electron-induced signals are considerably different from those observed during the first measurements carried out by the prototype Cherenkov probe in 2008. An explanation of the observed differences is given.

  16. Optical frequency up-conversion by supercontinuum-free widely-tunable fiber-optic Cherenkov radiation

    PubMed Central

    Tu, Haohua; Boppart, Stephen A.

    2010-01-01

    Spectrally-isolated narrowband Cherenkov radiation from commercial nonlinear photonic crystal fibers is demonstrated as an ultrafast optical source with a visible tuning range of 485–690 nm, which complementarily extends the near-infrared tuning range of 690–1020 nm from the corresponding femtosecond Ti:sapphire pump laser. Pump-to-signal conversion efficiency routinely surpasses 10%, enabling multimilliwatt visible output across the entire tuning range. Appropriate selection of fiber parameters and pumping conditions efficiently suppresses the supercontinuum generation typically associated with Cherenkov radiation. PMID:19506636

  17. 7 CFR 1794.71 - Adoption of an EA.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 7 Agriculture 12 2014-01-01 2013-01-01 true Adoption of an EA. 1794.71 Section 1794.71 Agriculture Regulations of the Department of Agriculture (Continued) RURAL UTILITIES SERVICE, DEPARTMENT OF AGRICULTURE (CONTINUED) ENVIRONMENTAL POLICIES AND PROCEDURES Adoption of Environmental Documents § 1794.71 Adoption...

  18. 47 CFR 101.1327 - Renewal expectancy for EA licensees.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 47 Telecommunication 5 2010-10-01 2010-10-01 false Renewal expectancy for EA licensees. 101.1327 Section 101.1327 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Multiple Address Systems System Requirements § 101.1327...

  19. 47 CFR 101.1327 - Renewal expectancy for EA licensees.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 47 Telecommunication 5 2011-10-01 2011-10-01 false Renewal expectancy for EA licensees. 101.1327 Section 101.1327 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Multiple Address Systems System Requirements § 101.1327...

  20. 47 CFR 101.1327 - Renewal expectancy for EA licensees.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 47 Telecommunication 5 2013-10-01 2013-10-01 false Renewal expectancy for EA licensees. 101.1327 Section 101.1327 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Multiple Address Systems System Requirements § 101.1327...

  1. 47 CFR 101.1327 - Renewal expectancy for EA licensees.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 47 Telecommunication 5 2012-10-01 2012-10-01 false Renewal expectancy for EA licensees. 101.1327 Section 101.1327 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Multiple Address Systems System Requirements § 101.1327...

  2. 7 CFR 1794.23 - Proposals normally requiring an EA.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... boundaries. (12) Installing a heat recovery steam generator and steam turbine with a rating of more than 200... classification are: (1) Construction of fuel cell, combustion turbine, combined cycle, or diesel generating... be covered in the EA; (2) Construction of fuel cell, combustion turbine, combined cycle, or...

  3. 7 CFR 1794.23 - Proposals normally requiring an EA.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... boundaries. (12) Installing a heat recovery steam generator and steam turbine with a rating of more than 200... classification are: (1) Construction of fuel cell, combustion turbine, combined cycle, or diesel generating... be covered in the EA; (2) Construction of fuel cell, combustion turbine, combined cycle, or...

  4. 7 CFR 1794.23 - Proposals normally requiring an EA.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... boundaries. (12) Installing a heat recovery steam generator and steam turbine with a rating of more than 200... classification are: (1) Construction of fuel cell, combustion turbine, combined cycle, or diesel generating... be covered in the EA; (2) Construction of fuel cell, combustion turbine, combined cycle, or...

  5. 7 CFR 1794.23 - Proposals normally requiring an EA.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... boundaries. (12) Installing a heat recovery steam generator and steam turbine with a rating of more than 200... classification are: (1) Construction of fuel cell, combustion turbine, combined cycle, or diesel generating... be covered in the EA; (2) Construction of fuel cell, combustion turbine, combined cycle, or...

  6. EAS array data in relativistic solar cosmic ray studies

    NASA Astrophysics Data System (ADS)

    Karpov, S. N.; Karpova, Z. M.; Balabin, Yu. V.; Vashenyuk, E. V.

    Extensive Air Shower EAS arrays in a 1-particle mode operation are cosmic ray detectors of great area and appear to be more sensitive than standard neutron monitors to solar cosmic ray at rigidity range 5 GV The paper considers GLE events study with using data of EAS-arrays Andyrchy 37 m 2 2050 m a s l Carpet 200 m 2 1700 m a s l and the Baksan Muon Detector BMD 190 m 2 5 m w e 1700 m a s l of the Baksan Neutrino Observatory BNO located at the North Caucasus 43 28 r N 42 69 r E At the BNO geomagnetic cutoff sim 6GV EAS-arrays were registered 15 of 30 or 50 of total GLE events occurred in the period since 1982 The 20 January 2005 GLE effect was equal at the Carpet array 0 90 pm 0 03 32 sigma and at the BMD 0 22 pm 0 04 5 5 sigma The start of increase was fixed at 06 55 UT and maximum - at 07 15 UT Adding of these data to the GLE modeling using neutron monitor data has allowed deriving more accurate spectrum of solar protons in the 5-10 GV range The coupling functions for the Baksan EAS arrays were calculated with KORSICA code

  7. 7 CFR 1794.23 - Proposals normally requiring an EA.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ...) at a fossil-fueled generating station where the existing fuel combustion technology of the affected... classification are: (1) Construction of fuel cell, combustion turbine, combined cycle, or diesel generating... be covered in the EA; (2) Construction of fuel cell, combustion turbine, combined cycle, or...

  8. Ganglion and “Dendrite” Populations in EAS Ears

    PubMed Central

    Rask-Andersen, Helge; Liu, Wei; Linthicum, Fred H

    2010-01-01

    Background/Aims EAS technique combines electric and acoustic stimulation in the same ear and utilizes both low frequency acoustic hearing and electric stimulation of preserved neurons. We present data of ganglion cell and dendrite populations in ears from normal individuals and those suffered from adult-onset hereditary progressive hearing loss with various residual low tone hearing. Some of these were potential candidates for EAS surgery. The data may give us information about the neuro-anatomic situation in EAS ears. Methods Dendrites and ganglion cells were calculated and audio-cytocochleograms constructed. The temporal bones were from the collection at the House Ear Institute in Los Angeles, USA. Normal human anatomy, based on surgical specimens, is presented. Results IHCs and OHCs, supporting cells, ganglion cells and dendrites were preserved in the apical region. In the mid-frequency region, around 1 kHz, the OC with inner and outer hair cells were often conserved while in the lower basal turn, representing frequencies above 3 kHz, OC was atrophic and replaced by thin cells. Despite loss of hair cells and lamina fibers ganglion cells were present even after 28 years duration of deafness. Conclusions Conditions with profound SNHL with preserved low tone hearing may have several causes and the pathology may vary accordingly. In our patients with progressive adult-onset SNHL (amalgamated into “presbyacusis”) neurons were conserved even after long duration of deafness. These spiral ganglion cells may be excellent targets for electric stimulation using EAS technique. PMID:19955718

  9. GEO-EAS (GEOSTATISTICAL ENVIRONMENTAL ASSESSMENT SOFTWARE) USER'S GUIDE

    EPA Science Inventory

    The report describes how to install and use the Geo-EAS (Geostatistical Environmental Assessment Software) software package on an IBM-PC compatible computer system. A detailed example is provided showing how to use the software to conduct a geostatistical analysis of a data set. ...

  10. 47 CFR 101.1311 - Initial EA license authorization.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 47 Telecommunication 5 2014-10-01 2014-10-01 false Initial EA license authorization. 101.1311 Section 101.1311 Telecommunication FEDERAL COMMUNICATIONS COMMISSION (CONTINUED) SAFETY AND SPECIAL RADIO SERVICES FIXED MICROWAVE SERVICES Multiple Address Systems System License Requirements § 101.1311...

  11. Cooperative parametric (quasi-Cherenkov) radiation produced by electron bunches in natural or photonic crystals

    NASA Astrophysics Data System (ADS)

    Anishchenko, S. V.; Baryshevsky, V. G.

    2015-07-01

    We study the features of cooperative parametric (quasi-Cherenkov) radiation arising when initially unmodulated electron (positron) bunches pass through a crystal (natural or artificial) under the conditions of dynamical diffraction of electromagnetic waves in the presence of shot noise. A detailed numerical analysis is given for cooperative THz radiation in artificial crystals. The radiation intensity above 200 MW/cm2 is obtained in simulations. The peak intensity of cooperative radiation emitted at small and large angles to particle velocity is investigated as a function of the current density of an electron bunch. The peak radiation intensity appeared to increase monotonically until saturation is achieved. At saturation, the shot noise causes strong fluctuations in the intensity of cooperative parametric radiation. It is shown that the duration of radiation pulses can be much longer than the particle flight time through the crystal. This enables a thorough experimental investigation of the time structure of cooperative parametric radiation generated by electron bunches available with modern accelerators. The complicated time structure of cooperative parametric (quasi-Cherenkov) radiation can be observed in crystals (natural or artificial) in all spectral ranges (X-ray, optical, terahertz, and microwave).

  12. Seismic analysis of the 4-meter telescope SST-GATE for the Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    Dournaux, Jean-Laurent; Huet, Jean-Michel; Amans, Jean-Philippe; Dumas, Delphine; Blake, Simon; Sol, Hélène

    2014-07-01

    The Cherenkov Telescope Array (CTA) project aims to create a next generation Very High Energy (VHE)γ-ray telescope array, devoted to the observation in a wide band of energy, from a few tens of GeV to more than 100 TeV. Two sites are foreseen to view the whole sky, with the main one in the Southern Hemisphere where about 100 telescopes of three different classes, related to the specific energy region to be investigated, will be installed. Among these, the Small Size class of Telescopes, SSTs, are 4-meter telescopes and are devoted to the highest energy region, from 1 TeV to beyond 100 TeV. Some of these sites considered for CTA exhibit strong seismic constraints. At the Observatoire de Paris, we have designed a prototype of a Small Size Telescope named SST-GATE, based on the dual-mirror Schwarzschild-Couder optical formula, which was never before implemented in the design of a Cherenkov telescope. The integration of this telescope on the site of the Observatoire de Paris is currently in progress. Technical solutions exist in the literature to protect structures from dynamic loads caused by earthquakes without increasing the mass and cost of the structure. This paper presents a state of the art of these techniques by keeping in mind that the operational performance of the telescope should not be compromised. The preliminary seismic analysis of SSTGATE performed by the finite element method is described before.

  13. Operation of the Cherenkov Detector DIRC of BaBar at High Luminosity

    SciTech Connect

    Spanier, Stefane

    2001-03-07

    The DIRC (acronym for Detection of Internally Reflected Cherenkov (light)) is the ring imaging Cherenkov detector of the BaBar detector at the Pep-II ring of SLAC. It provides the identification of pions, kaons and protons for momenta up to 4 GeV/c with high efficiency. This is needed to reconstruct CP-violating B-decay final states and to provide B-meson flavour tagging for time dependent asymmetry measurements. The DIRC radiators consists of long rectangular bars made of synthetic fused silica and the photon detector is a water tank equipped with an array of 10,752 conventional photomultipliers. At the end of the year 2000 BaBar has recorded about 22 million {bar B}B pairs reaching the design luminosity of L = 3 x 10{sup 33}/cm{sup 2}s. The ability to keep the beam background level low at highest collision rates and the long term reliability of the DIRC components during continuous data taking are requirements of BaBar to accomplish its physics program.

  14. Detection of Shielded Special Nuclear Material With a Cherenkov-Based Transmission Imaging System

    NASA Astrophysics Data System (ADS)

    Rose, Paul; Erickson, Anna; Mayer, Michael; Jovanovic, Igor

    2015-10-01

    Detection of shielded special nuclear material, SSNM, while in transit, offers a unique challenge. Typical cargo imaging systems are Bremsstrahlung-based and cause an abundance of unnecessary signal in the detectors and doses to the cargo contents and surroundings. Active interrogation with dual monoenergetic photons can unveil the illicit material when coupled with a high-contrast imaging system while imparting significantly less dose to the contents. Cherenkov detectors offer speed, resilience, inherent energy threshold rejection, directionality and scalability beyond the capability of most scintillators. High energy resolution is not a priority when using two well separated gamma rays, 4.4 and 15.1 MeV, generated from low energy nuclear reactions such as 11B(d,n- γ)12C. These gamma rays offer a measure of the effective atomic number, Z, of the cargo by taking advantage of the large difference in photon interaction cross sections, Compton scattering and pair production. This imaging system will be coupled to neutron detectors to provide unique signature of SNM by monitoring delayed neutrons. Our experiments confirm that the Cherenkov imaging system can be used with the monoenergetic source to relate transmission and atomic number of the scanned material.

  15. Design and Experimental Demonstration of Cherenkov Radiation Source Based on Metallic Photonic Crystal Slow Wave Structure

    NASA Astrophysics Data System (ADS)

    Fu, Tao; Yang, Zi-Qiang; Ouyang, Zheng-Biao

    2016-06-01

    This paper presents a kind of Cherenkov radiation source based on metallic photonic crystal (MPC) slow-wave structure (SWS) cavity. The Cherenkov source designed by linear theory works at 34.7 GHz when the cathode voltage is 550 kV. The three-dimensional particle-in-cell (PIC) simulation of the SWS shows the operating frequency of 35.56 GHz with a single TM01 mode is basically consistent with the theoretically one under the same parameters. An experiment was implemented to testify the results of theory and PIC simulation. The experimental system includes a cathode emitting unit, the SWS, a magnetic system, an output antenna, and detectors. Experimental results show that the operating frequency through detecting the retarded time of wave propagation in waveguides is around 35.5 GHz with a single TM01 mode and an output power reaching 54 MW. It indicates that the MPC structure can reduce mode competition. The purpose of the paper is to show in theory and in preliminary experiment that a SWS with PBG can produce microwaves in TM01 mode. But it still provides a good experimental and theoretical foundation for designing high-power microwave devices.

  16. A Search for Supersymmetric Q-balls with the High Altitude Water Cherenkov Observatory

    NASA Astrophysics Data System (ADS)

    Karn, Peter

    The High Altitude Water Cherenkov (HAWC) Observatory is a gamma-ray experiment currently under construction at Sierra Negra in Mexico. When complete it will consist of a 22,000 square meter array of 300 water Cherenkov detectors. Although HAWC is designed to study gamma rays from galactic and extra-galactic sources, the large volume of instrumented water (each tank holds ˜188,000 liters) gives the opportunity to search for rare objects. One such target is the Q-ball, a very massive, subrelativistic particle that can have a large baryon number and can be stable since their creation in the early universe. If stable, Q-balls would make up some of the dark matter of the universe, but their large mass means their flux is very low. HAWC has a flexible data acquisition system which, with a dedicated trigger algorithm for non-relativistic species, allows a search for Q-balls traversing the detector. Using a 174.5 days of live time and a portion of the planned array, a search was performed with negative results. The obtained upper limits are competitive with previously published limits on Q-balls, and HAWC will be able to set a better limit than any other when it is complete.

  17. Muon data from a water Cherenkov detector prototype at Colorado State University

    NASA Astrophysics Data System (ADS)

    Longo, Megan; Mostafa, Miguel

    2013-04-01

    The High Altitude Water Cherenkov (HAWC) Observatory is a very high energy gamma-ray experiment currently under construction in Sierra Negra in the state of Puebla, Mexico, at an altitude of 4,100 m a.s.l. The HAWC Observatory will consist of 300 water Cherenkov detectors (WCDs), each instrumented with three 8'' photomultiplier tubes (PMTs) and one 10'' high efficiency (HE) PMT. The PMTs are upward facing, anchored to the bottom of a 5 m deep by 7.3 m diameter steel tank, containing a multilayer hermetic plastic bag holding 200,000 L of purified water. The only full size WCD prototype outside of the HAWC site is located at Colorado State University (CSU) in Fort Collins, CO at an altitude of 1,525 m a.s.l. This prototype is instrumented with six 8'' PMTs, one 10'' HE PMT, and the same laser calibration system, electronics, and data acquisition system as the WCDs at the HAWC site. The CSU prototype is additionally equipped with scintillator paddles both under and above the volume of water, temperature probes (in the water, outside, and in the DAQ room), and one covered PMT. Preliminary results for muon rates and their temperature dependance using data collected with the CSU prototype will be presented.

  18. Development of Gigahertz Analog Memory for Front-End Electronics of Imaging Air Cherenkov Telescopes

    NASA Astrophysics Data System (ADS)

    Mizukami, T.; Higashi, Y.; Nakano, S.; Nakamori, T.; Kubo, H.; Tanimori, T.; Tanaka, M.

    The night sky light is one of the major components of background for imaging air Cherenkov telescopes. It disturbs images of air shower and makes both the gamma/hadron separation and the angular resolution worse. For example, The CANGAROO-III electronics consists of charge ADCs and multi-hit TDCs. In using charge ADCs, we have to delay the signal from PMTs until the trigger signal input to ADCs. After through this delay line chip, signals from PMTs are distorted, and we have to take the signal integration time longer than Cherenkov signal time constant and more night sky light is mixed to the real signal. In order to reduce this night sky light, we are planning to replace the charge ADCs to capacitor arrays called AMC (Analog Memory Cell). AMC consists of 512 capacitors and can record the waveform of the input signal for 512 ns at high sampling rate of 1 GHz. We already developed a test type of AMC chip and its dynamic range is more than 7 bits. We will report the current status of the development of AMC.

  19. Conceptual design and simulation of a water Cherenkov muon veto for the XENON1T experiment

    NASA Astrophysics Data System (ADS)

    Aprile, E.; Agostini, F.; Alfonsi, M.; Arisaka, K.; Arneodo, F.; Auger, M.; Balan, C.; Barrow, P.; Baudis, L.; Bauermeister, B.; Behrens, A.; Beltrame, P.; Bokeloh, K.; Breskin, A.; Brown, A.; Brown, E.; Bruenner, S.; Bruno, G.; Budnik, R.; Cardoso, J. M. R.; Colijn, A. P.; Contreras, H.; Cussonneau, J. P.; Decowski, M. P.; Duchovni, E.; Fattori, S.; Ferella, A. D.; Fulgione, W.; Garbini, M.; Geis, C.; Goetzke, L. W.; Grignon, C.; Gross, E.; Hampel, W.; Itay, R.; Kaether, F.; Kessler, G.; Kish, A.; Landsman, H.; Lang, R. F.; Le Calloch, M.; Lellouch, D.; Levinson, L.; Levy, C.; Lindemann, S.; Lindner, M.; Lopes, J. A. M.; Lung, K.; Lyashenko, A.; MacMullin, S.; Marrodán Undagoitia, T.; Masbou, J.; Massoli, F. V.; Mayani Paras, D.; Melgarejo Fernandez, A. J.; Meng, Y.; Messina, M.; Miguez, B.; Molinario, A.; Morana, G.; Murra, M.; Naganoma, J.; Oberlack, U.; Orrigo, S. E. A.; Pantic, E.; Persiani, R.; Piastra, F.; Pienaar, J.; Plante, G.; Priel, N.; Reichard, S.; Reuter, C.; Rizzo, A.; Rosendahl, S.; dos Santos, J. M. F.; Sartorelli, G.; Schindler, S.; Schreiner, J.; Schumann, M.; Scotto Lavina, L.; Selvi, M.; Shagin, P.; Simgen, H.; Teymourian, A.; Thers, D.; Tiseni, A.; Trinchero, G.; Vitells, O.; Wang, H.; Weber, M.; Weinheimer, C.

    2014-11-01

    XENON is a dark matter direct detection project, consisting of a time projection chamber (TPC) filled with liquid xenon as detection medium. The construction of the next generation detector, XENON1T, is presently taking place at the Laboratori Nazionali del Gran Sasso (LNGS) in Italy. It aims at a sensitivity to spin-independent cross sections of 2 · 10-47 c 2 for WIMP masses around 50 GeV2, which requires a background reduction by two orders of magnitude compared to XENON100, the current generation detector. An active system that is able to tag muons and muon-induced backgrounds is critical for this goal. A water Cherenkov detector of ~ 10 m height and diameter has been therefore developed, equipped with 8 inch photomultipliers and cladded by a reflective foil. We present the design and optimization study for this detector, which has been carried out with a series of Monte Carlo simulations. The muon veto will reach very high detection efficiencies for muons (>99.5%) and showers of secondary particles from muon interactions in the rock (>70%). Similar efficiencies will be obtained for XENONnT, the upgrade of XENON1T, which will later improve the WIMP sensitivity by another order of magnitude. With the Cherenkov water shield studied here, the background from muon-induced neutrons in XENON1T is negligible.

  20. Upgrade of the Cherenkov Detector of the JLab Hall A BigBite Spectrometer

    NASA Astrophysics Data System (ADS)

    Nycz, Michael

    2015-04-01

    The BigBite Spectrometer of the Hall A Facility of Jefferson Lab will be used in the upcoming MARATHON experiment at Jefferson Lab to measure the ratio of neutron to proton F2 inelastic structure functions and the ratio of up to down, d/u, quark nucleon distributions at medium and large values of Bjorken x. In preparation for this experiment, the BigBite Cherenkov detector is being modified to increase its overall efficiency for detecting electrons. This large volume counter is based on a dual system of segmented mirrors reflecting Cherenkov radiation to twenty photomultipliers. In this talk, a description of the detector and its past performance will be presented, along with the motivations for improvements and their implementation. An update on the status of the rest of the BigBite detector package, will be also presented. Additionally, current issues related to obtaining C4 F8 O, the commonly used radiator gas, which has been phased out of production by U.S. gas producers, will be discussed. This work is supported by Kent State University, NSF Grant PHY-1405814, and DOE Contract DE-AC05-06OR23177.

  1. The ASTRI SST-2M prototype for the Cherenkov Telescope Array: primary mirror characterization by deflectometry

    NASA Astrophysics Data System (ADS)

    Sironi, Giorgia; Canestrari, Rodolfo

    2015-09-01

    In 2014 the ASTRI Collaboration, led by the Italian National Institute for Astrophysics, has constructed an end-to-end prototype of a dual-mirror imaging air Cherenkov telescope, proposed for the small size class of telescopes for the Cherenkov Telescope Array. The prototype, named ASTRI SST-2M, has been installed at the observing station located at Serra La Nave (Italy). In this project the Brera Astronomical Observatory was responsible for the production and the testing of the primary mirror. The ASTRI SST-2M telescope's primary mirror has an aperture of ~ 4 m, a polynomial design, and consists of 18 individual hexagonal facets. These characteristics require the production and testing of panels with a typical size of ~1 m vertex-to-vertex and with an aspheric component of up to several millimetres. The mirror segments were produced assembling a sandwich of thin glass foils bent at room temperature to reach the desired shape. For the characterization of the mirrors we developed an ad-hoc deflectometry facility that works as an inverse Ronchi test in combination with a ray-tracing code. In this contribution we report the results of the deflectometric measurements performed on the primary mirror segments of the ASTRI SST-2M dual mirror telescope. The expected point spread function and the contributions to the degradation of the image quality are studied.

  2. QCD in the nuclear medium and effects due to Cherenkov gluons

    SciTech Connect

    Dremin, I. M.

    2010-04-15

    The equations of in-medium gluodynamics are proposed. Their classical lowest-order solution is explicitly shown for a color charge moving with constant speed. For chromopermittivity larger than 1 it describes emission of Cherenkov gluons resembling results of classical electrodynamics. The values of the real and imaginary parts of the chromopermittivity are obtained from the fits to experimental data on the double-humped structure around the away-side jet obtained at RHIC. The dispersion of the chromopermittivity is predicted by comparing the RHIC, SPS, and cosmic-ray data. This is important for LHC experiments. Cherenkov gluons may be responsible for the asymmetry of dilepton mass spectra near {rho} meson observed in the SPS experiment with excess in the low-mass wing of the resonance. This feature is predicted to be common for all resonances. The 'color rainbow' quantum effect might appear according to higher-order terms of in-medium QCD if the chromopermittivity depends on color.

  3. Calculation of the radio emission from EAS

    NASA Technical Reports Server (NTRS)

    Allan, H. R.; Sun, M. P.; Crannell, C. J.; Hough, J. H.; Shutie, P. F.

    1975-01-01

    Time-varying features of an electron-photon cascade are considered, particularly those associated with radio emission. The cosmic ray shower is represented as a superposition of collinear 10 GeV electron-photon cascades launched at different heights in the atmosphere. Actual simulations are performed for only 10 cascades at each of 40 heights and the results are scaled to represent the total number of cascades required. The apparent angular motions of the cascade particles as detected by antennas located at various positions up to 300 m from the shower axis are simulated. The radio pulse waveform and the corresponding frequency spectrum are obtained from these motions.

  4. A new paradigm for Environmental Assessment (EA) in Korea

    SciTech Connect

    Song, Young-Il; Glasson, John

    2010-02-15

    Over the last 30 years, Environmental Impact Assessment (EIA) in Korea has played an important role in decision-making processes particularly for environmentally sensitive projects. However, the EIA system alone has sometimes not been effective enough to ensure the successful resolution of environmental concerns. In order to compensate for the limitations of the EIA system, a new assessment system called Prior Environmental Review System (PERS), which is relevant to Strategic Environmental Assessment (SEA) in some aspects, was introduced in 1993. PERS aims to balance development and preservation by identifying possible environmental impacts of some administrative plans mainly related to development projects in the early stages of planning. However, PERS still appeared to have some weak points such as a limited range of subjects to be assessed, and weakness of tiering (or vertical integration) from PERS to EIA. Therefore, the necessity for reform of the Korean Environmental Assessment (EA) system, including PERS, was raised. In response, the Korean government sought to establish its policy direction for implementing SEA by enhancing the objectivity and expertise of PERS. The policy was approved by the National Assembly in May 2005, and went into effect in June 2006. The introduction of SEA, by enhancing PERS, provides a framework for a system of EA from the strategic level, including PPPs, to the project level. Yet, despite such improvements, some managerial and technical problems associated with subsequent EA implementation remain. This paper critically reviews the evolution of the EA system in Korea and suggests essential improvements for the current EA system based on experiences of implementation of both EIA and SEA since June 2006, in the context of international good practice.

  5. 75 FR 7949 - Airworthiness Directives; Extra Flugzeugproduktions- und Vertriebs- GmbH Models EA-300/200 and EA...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-02-23

    ... Register on November 3, 2009 (74 FR 56748). That NPRM proposed to correct an unsafe condition for the... Procedures (44 FR 11034, February 26, 1979); and (3) Will not have a significant economic impact, positive or... through 1043; and (2) Model EA-300/L airplanes, S/N 01 through 170, 172, 173, 1171, and 1174 through...

  6. Atmospheric Misconceptions.

    ERIC Educational Resources Information Center

    Aron, Robert H.

    1994-01-01

    Presents student survey results (n=708) of misconceptions held regarding the atmosphere. Results indicated a basic lack of understanding concerning atmospheric processes and phenomena. Although misconceptions generally decreased with increasing education, some seemed to be firmly rooted. (PR)

  7. The design and performance of a prototype water Cherenkov optical time-projection chamber

    NASA Astrophysics Data System (ADS)

    Oberla, Eric; Frisch, Henry J.

    2016-04-01

    A first experimental test of tracking relativistic charged particles by 'drifting' Cherenkov photons in a water-based optical time-projection chamber (OTPC) has been performed at the Fermilab Test Beam Facility. The prototype OTPC detector consists of a 77 cm long, 28 cm diameter, 40 kg cylindrical water mass instrumented with a combination of commercial 5.1 × 5.1cm2 micro-channel plate photo-multipliers (MCP-PMT) and 6.7 × 6.7cm2 mirrors. Five MCP-PMTs are installed in two columns along the OTPC cylinder in a small-angle stereo configuration. A mirror is mounted opposite each MCP-PMT on the inner surface of the detector cylinder, effectively increasing the photo-detection efficiency and providing a time-resolved image of the Cherenkov light on the opposing wall. Each MCP-PMT is coupled to an anode readout consisting of thirty 50 Ω microstrips. A 180-channel data acquisition system digitizes the MCP-PMT signals on one end of the microstrips using the PSEC4 waveform sampling-and-digitizing chip operating at a sampling rate of 10.24 Gigasamples-per-second. The single-ended microstrip readout determines the time and position of a photon arrival at the face of the MCP-PMT by recording both the direct signal and the pulse reflected from the unterminated far end of the strip. The detector was installed on the Fermilab MCenter secondary beam-line behind a steel absorber where the primary flux is multi-GeV muons. Approximately 80 Cherenkov photons are detected for a through-going muon track in a total event duration of ~2 ns. By measuring the time-of-arrival and the position of individual photons at the surface of the detector to ≤ 100 ps and a few mm, respectively, we have measured a spatial resolution of ~15 mm for each MCP-PMT track segment, and, from linear fits over the entire track length of ~40 cm, an angular resolution on the track direction of ~60 mrad.

  8. Design and development of a Gadolinium-doped water Cherenkov detector

    NASA Astrophysics Data System (ADS)

    Poudyal, Nabin

    This thesis describes a research and development project for neutron capture and detection in Gadolinium doped water. The Sanford Underground Research Facility (SURF) is exploring rare event physics, such as neutrinoless double beta decay (MAJORANA Project) and dark-matter detection (LUX experiment). The success of these experiments requires a careful study and understanding of background radiation, including flux and energy spectrum. The background radiation from surface contamination, radioactive decays of U-238, Th-232, Rn-222 in the surrounding rocks and muon induced neutrons have a large impact on the success of rare-event physics. The main objective of this R&D project is to measure the neutron flux contributing to ongoing experiments at SURF and suppress it by identification and capture method. For this purpose, we first modeled and designed a detector with Geant4 software. The approximate dimension of the detector is determined. The neutron capture percentage of the detector is estimated using Monte Carlo. The energy response of the detector is simulated. Next, we constructed the experimental detector, an acrylic rectangular tank (60cm x 30cm x 30cm), filled with Gadolinium-doped deionized water. The tank is coated with high efficient reflector and then taped with black electrical tape to make it opaque. The voltage dividers attached to PMTs are covered with mu-metal. Two 5-inch Hamamatsu Photomultiplier tubes were attached on both sides facing the tank to collect the Cherenkov light produced in the water. The detector utilizes the principle of Cherenkov light emission by a charged particle moving through a water at a speed higher than the speed of light in the water, hence it has an inherent energy threshold of Cherenkov photon production. This property reduces the lower energy backgrounds. Event data are obtained using the Data Acquisition hardware, Flash Analog to digital converter, along with Multi Instance Data Acquisition software. Post

  9. The High Altitude Water Cherenlov (HAWC) Gamma ray Detector Response to Atmospheric Electric Field Variations

    NASA Astrophysics Data System (ADS)

    Lara, A.

    2015-12-01

    The High Altitude Water Cherenkov (HAWC) observatory is located at 4100 m a.s.l. in Mexico. HAWC's primary purpose is the study of both: galactic and extra-galactic sources of high energy gamma rays. HAWC consists of 300 large water Cherenkov detectors (WCD), each instrumented with 4 photo-multipliers (PMTs). The HAWC scaler system records the rates of individual PMTs giving the opportunity of study relatively low energy transients as solar energetic particles, the solar modulation of galactic cosmic rays and possible variations of the cosmic ray rate due to atmospheric electric field changes. In this work, we present the observations of scaler rate enhancements associated with thunderstorm activity observed at the HAWC site.In particular, we present preliminary results of the analysis of the time coincidence of the electric field changes and the scaler enhancements.

  10. 110th anniversary of the birth of P A Cherenkov (Scientific session of the Physical Sciences Division of the Russian Academy of Sciences, 17 December 2014)

    NASA Astrophysics Data System (ADS)

    2015-05-01

    A scientific session of the Physical Sciences Division of the Russian Academy of Sciences (RAS) was held on 17 December 2014 at the conference hall of the Lebedev Physical Institute, RAS, devoted to the 110th anniversary of the birth of Academician P A Cherenkov. The agenda posted on the website of the Physical Sciences Division RAS http://www.gpad.ac.ru comprised the following reports: (1) Bashmakov Yu A (Lebedev Physical Institute, RAS, Moscow) "Prehistory of discovery"; (2) Kadmensky S G (Voronezh State University, Voronezh) "Cherenkov radiation as a serendipity phenomenon"; (3) Denisov S P (Russian Federation State Scientific Center 'Institute for High Energy Physics' of National Research Center 'Kurchatov Institute', Protvino, Moscow region) "Use of Cherenkov counters in accelerator experiments"; (4) Petrukhin A A (National Research Nuclear University 'MEPhI', Moscow) "Cherenkov NEVOD water detector"; (5) Dremin I M (Lebedev Physical Institute, RAS, Moscow) "Cherenkov radiation from gluons in a nuclear medium"; (6) Domogatsky G V (Institute for Nuclear Research, RAS, Moscow) "Cherenkov detectors for high-energy neutrino astrophysics"; (7) Kravchenko E A (Budker Institute of Nuclear Physics, SB RAS, Novosibirsk) "Cherenkov detectors with aerogel radiators"; (8) Malinovski E I (Institute for Nuclear Research, RAS, Moscow) "Cherenkov total absorption spectrometers for high-energy electrons and photons"; (9) Maltseva Yu I (Budker Institute of Nuclear Physics, SB RAS, Novosibirsk) "Distributed beam loss monitor based on the Cherenkov effect in an optical fiber". Papers based on oral reports 1-4, 6-9 are presented below. Some aspects of report 5 can be found in the review by I M Dremin and A V Leonidov published in 2010 in Physics-Uspekhi (Vol. 53, p. 1123). • Cherenkov radiation: from discovery to RICH, Yu A Bashmakov Physics-Uspekhi, 2015, Volume 58, Number 5, Pages 467-471 • Cherenkov radiation as a serendipitous phenomenon, S G Kadmensky Physics

  11. On the sensitivity of atmospheric Cherenkov telescope arrays for regions with presence of multiple gamma-ray sources

    NASA Astrophysics Data System (ADS)

    Ambrogi, L.; Aharonian, F.; De Oña Wilhelmi, E.

    2016-05-01

    The potential of a next-generation ground based gamma-ray telescope array has been investigated. In addition to the ideal Gaussian shaped PSF, more realistic non-Gaussian PSFs with tails have been considered and their impact on the detector performance has been studied. The capability of the instrument to resolve multiple sources has been analyzed and the corresponding detector sensitivity estimated. These scenarios are particularly interesting in the framework of Galactic objects, where the observation of more than one source in the same field of view (FoV) is very likely to happen.

  12. Advances In Atmospheric Acoustic Sounding

    NASA Astrophysics Data System (ADS)

    Bradley, S. G.; von Hunerbein, S.

    Acoustic sounders (SODAR) have developed as a useful and reliable operational tool for atmospheric boundary layer studies. This means that the effort in SODAR design can now be directed toward extended range, more compact design, use in more dif- ficult environments, and into extracting more information content from the scattered signals. We describe leading-edge developments and approaches in each of these ar- eas, but particularly with reference to the work by the Salford UK team. Specifically, we discuss: new hardware implementations using pulse-coding; progress and the pro- jected use of a suitcase-SODAR; baffle/beam requirements for use in urban environ- ments; multi-frequency methods of separating observables; use of multiple-SODAR arrays; multi-phase precipitation measurements; and inverse-method techniques for systematic optimization of data retrievals.

  13. Multiple shell shower fronts in EAS with ARGO-YBJ

    NASA Astrophysics Data System (ADS)

    Marsella, G.

    2015-08-01

    The ARGO-YBJ experiment is an Extensive Air Shower array that has been operated at the high altitude Yangbajing Cosmic Ray Laboratory (Tibet, P.R. China 4300 m a.s.l.) in its final configuration since December 2007 until February 2013. The detector consists of a dense layer of Resistive Plate Counters (RPCs) covering an area of about 11000 m2. It has been designed to measure the temporal and spatial structure of Extensive Air Showers (EAS) with high space-time resolution. The detector gives a quite highly detailed picture of shower footprints at ground. It is perfectly suitable to understand the EAS morphology. These detector characteristics have been used for seeking particles of large rest mass produced in cosmic rays by measuring the Multiple Shell Shower Fronts relative delays. The technique and preliminary results will be illustrated in the present work.

  14. Cosmic ray spectra measurements at the Yakutsk EAS array

    NASA Technical Reports Server (NTRS)

    Glushkov, A. V.; Egorov, T. A.; Efimov, N. N.; Pravdin, M. I.; Khristiansen, G. B.

    1985-01-01

    The extensive air showers (EAS) spectra on rho 600 obtained at the Yakutak array for 38000 operation hours in 1974 to 1982 are presented. The refined value of the conversion factor from rho 600 to E sub is given and based on it the primary energy spectrum is obtained. The Yakutsk EAS array classifies the showers on parameters which are well measured in real showers: in the central part - on Rho sub 300 and on the whole array - on Rho sub 600. The shower spectra are constructed first on these parameters, than - a single spectrum on Rho sub 600. The RHO sub 300 and Rho sub 600 values are determined on the particle lateral distribution function (LDF) obtained in Yakutsk and on approximation Rho approx. R sup/n using the experimental points closest to R* (300 and 600 m).

  15. Scaling behaviour of lateral distribution of electrons in EAS

    NASA Astrophysics Data System (ADS)

    Dey, R. K.; Bhadra, A.; Capdevielle, J. N.

    2012-08-01

    From a Monte Carlo simulation study of cosmic ray air showers around the knee of the primary energy spectrum it is shown that, despite a strong radial dependence of the lateral shower age parameter, the lateral density distribution of electrons in cosmic ray EAS displays universality when expressed in terms of local age parameters. The nature of the radial variation of local age is found to depend on the choice of the effective Moliere radius, particularly for radial distances below about 400 m. The possible use of shower age parameters in a multi-parameter study of EAS for extracting information about the nature of the shower initiating particles, has been re-examined.

  16. Experiment SPHERE status 2006 and CR composition determination by means of Cherenkov light LDF

    NASA Astrophysics Data System (ADS)

    Antonov, R. A.; Anyuhina, A. M.; Bronvech, E. A.; Chernov, D. V.; Galkin, V. I.; Lubnin, A. A.; Pushkarev, D. A.; Sysoeva, T. I.; Shaulov, S. B.; Shihaliev, F. O.; Tkaczyk, W.; Finger, M.; Sonsky, M.

    2008-01-01

    The modern status of the SPHERE experiment and the method to determine the primary energy and the kind of the primary nuclear particles is presented. The SPHERE experiment is based on A.E.Chudakov's suggestion to use a new method for investigating the ultra high energy primary cosmic ray energy spectrum [A.E. Chudakov, Trudy conf. po cosm. lutcham, (in Russian), p.69, Yakutsk, 1972]. A small device lifted above the snow surface of the Earth detects the Cherenkov light of extensive air showers reflected from the surface. The relatively simple detector SPHERE-2 (spherical mirror 1.5 m diameter and retina of 100 pixels) is presented. The next plan of the SPHERE experiment is to start measurements of the cosmic ray spectrum in the energy range 10-10 eV above the snow surface of Lake Baikal.

  17. Generation of Electromagnetic Fields of Extremely High Intensity by Coherent Summation of Cherenkov Superradiance Pulses

    NASA Astrophysics Data System (ADS)

    Ginzburg, N. S.; Cross, A. W.; Golovanov, A. A.; Mesyats, G. A.; Pedos, M. S.; Phelps, A. D. R.; Romanchenko, I. V.; Rostov, V. V.; Rukin, S. N.; Sharypov, K. A.; Shpak, V. G.; Shunailov, S. A.; Ulmaskulov, M. R.; Yalandin, M. I.; Zotova, I. V.

    2015-09-01

    We demonstrate both theoretically and experimentally the possibility of correlating the phase of a Cherenkov superradiance (SR) pulse to the sharp edge of a current pulse, when spontaneous emission of the electron bunch edge serves as the seed for SR processes. By division of the driving voltage pulse across several parallel channels equipped with independent cathodes we can synchronize several SR sources to arrange a two-dimensional array. In the experiments carried out, coherent summation of radiation from four independent 8-mm wavelength band SR generators with peak power 600 MW results in the interference maximum of the directional diagram with an intensity that is equivalent to radiation from a single source with a power of 10 GW.

  18. A facility to evaluate the focusing performance of mirrors for Cherenkov Telescopes

    NASA Astrophysics Data System (ADS)

    Canestrari, Rodolfo; Giro, Enrico; Bonnoli, Giacomo; Farisato, Giancarlo; Lessio, Luigi; Rodeghiero, Gabriele; Spiga, Rossella; Toso, Giorgio; Pareschi, Giovanni

    2016-01-01

    Cherenkov Telescopes are equipped with optical dishes of large diameter - in general based on segmented mirrors - with typical angular resolution of a few arc-minutes. To evaluate the mirror's quality specific metrological systems are required that possibly take into account the environmental conditions in which typically these telescopes operate (in open air without dome protection). For this purpose a new facility for the characterization of mirrors has been developed at the labs of the Osservatorio Astronomico di Brera of the Italian National Institute of Astrophysics. The facility allows the precise measurement of the radius of curvature and the distribution of the concentred light in terms of focused and scattered components and it works in open air. In this paper we describe the facility and report some examples of its measuring capabilities.

  19. An Ultra-High Gradient Cherenkov Wakefield Acceleration Experiment at SLAC FFTB

    SciTech Connect

    Rosenzweig, J.B.; Hoover, S.; Hogan, M.J.; Muggli, P.; Thompson, M.; Travish, G.; Yoder, R.; /UCLA /SLAC /Southern California U.

    2005-08-02

    The creation of ultra-high current, ultra-short pulse beams Q=3 nC, {sigma}{sub z} = 20{micro}m at the SLAC FFTB has opened the way for very high gradient plasma wakefield acceleration experiments. We study here the use of these beams in a proposed Cherenkov wakefield experiment, where one may excite electromagnetic wakes in a simple dielectric tube with inner diameter of few 100 microns that exceed the GV/m level. We discuss the scaling of the fields with design geometric design parameters, and choice of dielectric. We also examine measurable aspects of the experiment, such as the total coherent Cerenkov radiation energy one may collect, and the expected aspects of dielectric breakdown at high fields.

  20. Demonstrating gain in a dielectric Cherenkov maser with a rod slow-wave system

    NASA Astrophysics Data System (ADS)

    Avgustinovich, V. A.; Artemenko, S. N.; Mashchenko, A. I.; Shlapakovskii, A. S.; Yushkov, Yu. G.

    2010-03-01

    We report the first results of experiments that demonstrate the amplification of megawatt nanosecond microwave pulses in a Cherenkov maser with a dielectric rod and moderately relativistic annular electric beam generated in a compact linear induction accelerator module. The input signal was generated by a resonant microwave compressor operating in a 3-cm wavelength range. A maximum gain of ˜12.5 dB and a maximum output power of ˜16 MW for a pulse duration of ˜4 ns at a frequency of 9.388 GHz were obtained with a quartz rod. The dependence of the gain on the compressor power was determined for various values of the accelerating voltage and beam current.

  1. Search for long-lived heavy charged particles using a ring imaging Cherenkov technique at LHCb

    NASA Astrophysics Data System (ADS)

    Aaij, R.; Adeva, B.; Adinolfi, M.; Affolder, A.; Ajaltouni, Z.; Akar, S.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; Alvarez Cartelle, P.; Alves, A. A., Jr.; Amato, S.; Amerio, S.; Amhis, Y.; An, L.; Anderlini, L.; Anderson, J.; Andreotti, M.; Andrews, J. E.; Appleby, R. B.; Aquines Gutierrez, O.; Archilli, F.; d'Argent, P.; Artamonov, A.; Artuso, M.; Aslanides, E.; Auriemma, G.; Baalouch, M.; Bachmann, S.; Back, J. J.; Badalov, A.; Baesso, C.; Baldini, W.; Barlow, R. J.; Barschel, C.; Barsuk, S.; Barter, W.; Batozskaya, V.; Battista, V.; Bay, A.; Beaucourt, L.; Beddow, J.; Bedeschi, F.; Bediaga, I.; Bel, L. J.; Belyaev, I.; Ben-Haim, E.; Bencivenni, G.; Benson, S.; Benton, J.; Berezhnoy, A.; Bernet, R.; Bertolin, A.; Bettler, M.-O.; van Beuzekom, M.; Bien, A.; Bifani, S.; Bird, T.; Birnkraut, A.; Bizzeti, A.; Blake, T.; Blanc, F.; Blouw, J.; Blusk, S.; Bocci, V.; Bondar, A.; Bondar, N.; Bonivento, W.; Borghi, S.; Borgia, A.; Borsato, M.; Bowcock, T. J. V.; Bowen, E.; Bozzi, C.; Brett, D.; Britsch, M.; Britton, T.; Brodzicka, J.; Brook, N. H.; Bursche, A.; Buytaert, J.; Cadeddu, S.; Calabrese, R.; Calvi, M.; Calvo Gomez, M.; Campana, P.; Campora Perez, D.; Capriotti, L.; Carbone, A.; Carboni, G.; Cardinale, R.; Cardini, A.; Carniti, P.; Carson, L.; Carvalho Akiba, K.; Casanova Mohr, R.; Casse, G.; Cassina, L.; Castillo Garcia, L.; Cattaneo, M.; Cauet, Ch.; Cavallero, G.; Cenci, R.; Charles, M.; Charpentier, Ph.; Chefdeville, M.; Chen, S.; Cheung, S. F.; Chiapolini, N.; Chrzaszcz, M.; Cid Vidal, X.; Ciezarek, G.; Clarke, P. E. L.; Clemencic, M.; Cliff, H. V.; Closier, J.; Coco, V.; Cogan, J.; Cogneras, E.; Cogoni, V.; Cojocariu, L.; Collazuol, G.; Collins, P.; Comerma-Montells, A.; Contu, A.; Cook, A.; Coombes, M.; Coquereau, S.; Corti, G.; Corvo, M.; Counts, I.; Couturier, B.; Cowan, G. A.; Craik, D. C.; Crocombe, A.; Cruz Torres, M.; Cunliffe, S.; Currie, R.; D'Ambrosio, C.; Dalseno, J.; David, P. N. Y.; Davis, A.; De Bruyn, K.; De Capua, S.; De Cian, M.; De Miranda, J. M.; De Paula, L.; De Silva, W.; De Simone, P.; Dean, C. T.; Decamp, D.; Deckenhoff, M.; Del Buono, L.; Déléage, N.; Derkach, D.; Deschamps, O.; Dettori, F.; Dey, B.; Di Canto, A.; Di Ruscio, F.; Dijkstra, H.; Donleavy, S.; Dordei, F.; Dorigo, M.; Dosil Suárez, A.; Dossett, D.; Dovbnya, A.; Dreimanis, K.; Dujany, G.; Dupertuis, F.; Durante, P.; Dzhelyadin, R.; Dziurda, A.; Dzyuba, A.; Easo, S.; Egede, U.; Egorychev, V.; Eidelman, S.; Eisenhardt, S.; Eitschberger, U.; Ekelhof, R.; Eklund, L.; El Rifai, I.; Elsasser, Ch.; Ely, S.; Esen, S.; Evans, H. M.; Evans, T.; Falabella, A.; Färber, C.; Farinelli, C.; Farley, N.; Farry, S.; Fay, R.; Ferguson, D.; Fernandez Albor, V.; Ferrari, F.; Ferreira Rodrigues, F.; Ferro-Luzzi, M.; Filippov, S.; Fiore, M.; Fiorini, M.; Firlej, M.; Fitzpatrick, C.; Fiutowski, T.; Fol, P.; Fontana, M.; Fontanelli, F.; Forty, R.; Francisco, O.; Frank, M.; Frei, C.; Frosini, M.; Fu, J.; Furfaro, E.; Gallas Torreira, A.; Galli, D.; Gallorini, S.; Gambetta, S.; Gandelman, M.; Gandini, P.; Gao, Y.; García Pardiñas, J.; Garofoli, J.; Garra Tico, J.; Garrido, L.; Gascon, D.; Gaspar, C.; Gauld, R.; Gavardi, L.; Gazzoni, G.; Geraci, A.; Gerick, D.; Gersabeck, E.; Gersabeck, M.; Gershon, T.; Ghez, Ph.; Gianelle, A.; Gianì, S.; Gibson, V.; Giubega, L.; Gligorov, V. V.; Göbel, C.; Golubkov, D.; Golutvin, A.; Gomes, A.; Gotti, C.; Grabalosa Gándara, M.; Graciani Diaz, R.; Granado Cardoso, L. A.; Graugés, E.; Graverini, E.; Graziani, G.; Grecu, A.; Greening, E.; Gregson, S.; Griffith, P.; Grillo, L.; Grünberg, O.; Gui, B.; Gushchin, E.; Guz, Yu.; Gys, T.; Hadjivasiliou, C.; Haefeli, G.; Haen, C.; Haines, S. C.; Hall, S.; Hamilton, B.; Hampson, T.; Han, X.; Hansmann-Menzemer, S.; Harnew, N.; Harnew, S. T.; Harrison, J.; He, J.; Head, T.; Heijne, V.; Hennessy, K.; Henrard, P.; Henry, L.; Hernando Morata, J. A.; van Herwijnen, E.; Heß, M.; Hicheur, A.; Hill, D.; Hoballah, M.; Hombach, C.; Hulsbergen, W.; Humair, T.; Hussain, N.; Hutchcroft, D.; Hynds, D.; Idzik, M.; Ilten, P.; Jacobsson, R.; Jaeger, A.; Jalocha, J.; Jans, E.; Jawahery, A.; Jing, F.; John, M.; Johnson, D.; Jones, C. R.; Joram, C.; Jost, B.; Jurik, N.; Kandybei, S.; Kanso, W.; Karacson, M.; Karbach, T. M.; Karodia, S.; Kelsey, M.; Kenyon, I. R.; Kenzie, M.; Ketel, T.; Khanji, B.; Khurewathanakul, C.; Klaver, S.; Klimaszewski, K.; Kochebina, O.; Kolpin, M.; Komarov, I.; Koopman, R. F.; Koppenburg, P.; Kravchuk, L.; Kreplin, K.; Kreps, M.; Krocker, G.; Krokovny, P.; Kruse, F.; Kucewicz, W.; Kucharczyk, M.; Kudryavtsev, V.; Kurek, K.; Kvaratskheliya, T.; La Thi, V. N.; Lacarrere, D.; Lafferty, G.; Lai, A.; Lambert, D.; Lambert, R. W.; Lanfranchi, G.; Langenbruch, C.; Langhans, B.; Latham, T.; Lazzeroni, C.; Le Gac, R.; van Leerdam, J.; Lees, J. P.; Lefèvre, R.; Leflat, A.; Lefrançois, J.; Leroy, O.; Lesiak, T.; Leverington, B.; Li, Y.; Likhomanenko, T.; Liles, M.; Lindner, R.; Linn, C.; Lionetto, F.; Liu, B.; Lohn, S.; Longstaff, I.; Lopes, J. H.; Lucchesi, D.; Luo, H.; Lupato, A.; Luppi, E.; Lupton, O.; Machefert, F.; Machikhiliyan, I. V.; Maciuc, F.; Maev, O.; Malde, S.; Malinin, A.; Manca, G.; Mancinelli, G.; Manning, P.; Mapelli, A.; Maratas, J.; Marchand, J. F.; Marconi, U.; Marin Benito, C.; Marino, P.; Märki, R.; Marks, J.; Martellotti, G.; Martinelli, M.; Martinez Santos, D.; Martinez Vidal, F.; Martins Tostes, D.; Massafferri, A.; Matev, R.; Mathe, Z.; Matteuzzi, C.; Mauri, A.; Maurin, B.; Mazurov, A.; McCann, M.; McCarthy, J.; McNab, A.; McNulty, R.; McSkelly, B.; Meadows, B.; Meier, F.; Meissner, M.; Merk, M.; Milanes, D. A.; Minard, M. N.; Mitzel, D. S.; Molina Rodriguez, J.; Monteil, S.; Morandin, M.; Morawski, P.; Mordà, A.; Morello, M. J.; Moron, J.; Morris, A. B.; Mountain, R.; Muheim, F.; Müller, J.; Müller, K.; Müller, V.; Mussini, M.; Muster, B.; Naik, P.; Nakada, T.; Nandakumar, R.; Nasteva, I.; Needham, M.; Neri, N.; Neubert, S.; Neufeld, N.; Neuner, M.; Nguyen, A. D.; Nguyen, T. D.; Nguyen-Mau, C.; Niess, V.; Niet, R.; Nikitin, N.; Nikodem, T.; Novoselov, A.; O'Hanlon, D. P.; Oblakowska-Mucha, A.; Obraztsov, V.; Ogilvy, S.; Okhrimenko, O.; Oldeman, R.; Onderwater, C. J. G.; Osorio Rodrigues, B.; Otalora Goicochea, J. M.; Otto, A.; Owen, P.; Oyanguren, A.; Palano, A.; Palombo, F.; Palutan, M.; Panman, J.; Papanestis, A.; Pappagallo, M.; Pappalardo, L. L.; Parkes, C.; Passaleva, G.; Patel, G. D.; Patel, M.; Patrignani, C.; Pearce, A.; Pellegrino, A.; Penso, G.; Pepe Altarelli, M.; Perazzini, S.; Perret, P.; Pescatore, L.; Petridis, K.; Petrolini, A.; Picatoste Olloqui, E.; Pietrzyk, B.; Pilař, T.; Pinci, D.; Pistone, A.; Playfer, S.; Plo Casasus, M.; Poikela, T.; Polci, F.; Poluektov, A.; Polyakov, I.; Polycarpo, E.; Popov, A.; Popov, D.; Popovici, B.; Potterat, C.; Price, E.; Price, J. D.; Prisciandaro, J.; Pritchard, A.; Prouve, C.; Pugatch, V.; Puig Navarro, A.; Punzi, G.; Qian, W.; Quagliani, R.; Rachwal, B.; Rademacker, J. H.; Rakotomiaramanana, B.; Rama, M.; Rangel, M. S.; Raniuk, I.; Rauschmayr, N.; Raven, G.; Redi, F.; Reichert, S.; Reid, M. M.; dos Reis, A. C.; Ricciardi, S.; Richards, S.; Rihl, M.; Rinnert, K.; Rives Molina, V.; Robbe, P.; Rodrigues, A. B.; Rodrigues, E.; Rodriguez Perez, P.; Roiser, S.; Romanovsky, V.; Romero Vidal, A.; Rotondo, M.; Rouvinet, J.; Ruf, T.; Ruiz, H.; Ruiz Valls, P.; Saborido Silva, J. J.; Sagidova, N.; Sail, P.; Saitta, B.; Salustino Guimaraes, V.; Sanchez Mayordomo, C.; Sanmartin Sedes, B.; Santacesaria, R.; Santamarina Rios, C.; Santovetti, E.; Sarti, A.; Satriano, C.; Satta, A.; Saunders, D. M.; Savrina, D.; Schiller, M.; Schindler, H.; Schlupp, M.; Schmelling, M.; Schmelzer, T.; Schmidt, B.; Schneider, O.; Schopper, A.; Schune, M. H.; Schwemmer, R.; Sciascia, B.; Sciubba, A.; Semennikov, A.; Sepp, I.; Serra, N.; Serrano, J.; Sestini, L.; Seyfert, P.; Shapkin, M.; Shapoval, I.; Shcheglov, Y.; Shears, T.; Shekhtman, L.; Shevchenko, V.; Shires, A.; Silva Coutinho, R.; Simi, G.; Sirendi, M.; Skidmore, N.; Skillicorn, I.; Skwarnicki, T.; Smith, E.; Smith, E.; Smith, J.; Smith, M.; Snoek, H.; Sokoloff, M. D.; Soler, F. J. P.; Soomro, F.; Souza, D.; Souza De Paula, B.; Spaan, B.; Spradlin, P.; Sridharan, S.; Stagni, F.; Stahl, M.; Stahl, S.; Steinkamp, O.; Stenyakin, O.; Sterpka, F.; Stevenson, S.; Stoica, S.; Stone, S.; Storaci, B.; Stracka, S.; Straticiuc, M.; Straumann, U.; Stroili, R.; Sun, L.; Sutcliffe, W.; Swientek, K.; Swientek, S.; Syropoulos, V.; Szczekowski, M.; Szczypka, P.; Szumlak, T.; T'Jampens, S.; Tekampe, T.; Teklishyn, M.; Tellarini, G.; Teubert, F.; Thomas, C.; Thomas, E.; van Tilburg, J.; Tisserand, V.; Tobin, M.; Todd, J.; Tolk, S.; Tomassetti, L.; Tonelli, D.; Topp-Joergensen, S.; Torr, N.; Tournefier, E.; Tourneur, S.; Trabelsi, K.; Tran, M. T.; Tresch, M.; Trisovic, A.; Tsaregorodtsev, A.; Tsopelas, P.; Tuning, N.; Ubeda Garcia, M.; Ukleja, A.; Ustyuzhanin, A.; Uwer, U.; Vacca, C.; Vagnoni, V.; Valenti, G.; Vallier, A.; Vazquez Gomez, R.; Vazquez Regueiro, P.; Vázquez Sierra, C.; Vecchi, S.; Velthuis, J. J.; Veltri, M.; Veneziano, G.; Vesterinen, M.; Viaud, B.; Vieira, D.; Vieites Diaz, M.; Vilasis-Cardona, X.; Vollhardt, A.; Volyanskyy, D.; Voong, D.; Vorobyev, A.; Vorobyev, V.; Voß, C.; de Vries, J. A.; Waldi, R.; Wallace, C.; Wallace, R.; Walsh, J.; Wandernoth, S.; Wang, J.; Ward, D. R.; Watson, N. K.; Websdale, D.; Weiden, A.; Whitehead, M.; Wiedner, D.; Wilkinson, G.; Wilkinson, M.; Williams, M.; Williams, M. P.; Williams, M.; Wilson, F. F.; Wimberley, J.; Wishahi, J.; Wislicki, W.; Witek, M.; Wormser, G.; Wotton, S. A.; Wright, S.; Wyllie, K.; Xie, Y.; Xu, Z.; Yang, Z.; Yuan, X.; Yushchenko, O.; Zangoli, M.; Zavertyaev, M.; Zhang, L.; Zhang, Y.; Zhelezov, A.; Zhokhov, A.; Zhong, L.

    2015-12-01

    A search is performed for heavy long-lived charged particles using 3.0 fb^{-1} of proton-proton collisions collected at √{s} = 7 and 8 TeV with the LHCb detector. The search is mainly based on the response of the ring imaging Cherenkov detectors to distinguish the heavy, slow-moving particles from muons. No evidence is found for the production of such long-lived states. The results are expressed as limits on the Drell-Yan production of pairs of long-lived particles, with both particles in the LHCb pseudorapidity acceptance, 1.8 < η < 4.9. The mass-dependent cross-section upper limits are in the range 2-4 fb (at 95 % CL) for masses between 14 and 309 { GeV/c^2}.

  2. Monte Carlo validation experiments for the gas Cherenkov detectors at the National Ignition Facility and Omega.

    PubMed

    Rubery, M S; Horsfield, C J; Herrmann, H; Kim, Y; Mack, J M; Young, C; Evans, S; Sedillo, T; McEvoy, A; Caldwell, S E; Grafil, E; Stoeffl, W; Milnes, J S

    2013-07-01

    The gas Cherenkov detectors at NIF and Omega measure several ICF burn characteristics by detecting multi-MeV nuclear γ emissions from the implosion. Of primary interest are γ bang-time (GBT) and burn width defined as the time between initial laser-plasma interaction and peak in the fusion reaction history and the FWHM of the reaction history respectively. To accurately calculate such parameters the collaboration relies on Monte Carlo codes, such as GEANT4 and ACCEPT, for diagnostic properties that cannot be measured directly. This paper describes a series of experiments performed at the High Intensity γ Source (HIγS) facility at Duke University to validate the geometries and material data used in the Monte Carlo simulations. Results published here show that model-driven parameters such as intensity and temporal response can be used with less than 50% uncertainty for all diagnostics and facilities. PMID:23902060

  3. Measuring direct drive ICF remaining ablator areal density using a gas Cherenkov detector

    NASA Astrophysics Data System (ADS)

    Rubery, Michael; Horsfield, Colin; Herrmann, Hans; Kim, Yongho; Hoffmann, Nelson; Mack, Joseph; Young, Carl; Evans, Scott; Sedillo, Tom; Caldwell, Steven; Grafil, Elliot; Stoeffl, Wolfgang; Milnes, James; Atomic Weapons Establishment PLC Team; Los Alamos National Laboratory Team; Lawrence Livermore National Laboratory Team; Photek Ltd Team

    2013-10-01

    Neutrons from a compressed direct drive ICF target produce γ rays through inelastic interactions with ablator material. The inelastic γ intensity is proportional to the remaining ablator areal density at bang time and the neutron yield. Remaining ablator areal density is an important metric for the quality of the implosion and is strongly correlated with fuel temperature and compression. This contribution describes how a background signal routinely measured on the gas Cherenkov detectors can be used to infer the intensity of the low-energy inelastic gammas from the ablator on the same trace as the DT fusion γ signal, which is directly proportional to the neutron yield; therefore allowing the remaining ablator areal density to be measured in a self consistent manner. Results from recent experiments at the Omega laser facility designed to prove the technique are discussed. In addition, Monte Carlo modelling shows the technique can be used to measure remaining ablator areal density for both plastic and glass capsules.

  4. Strangeonium spectroscopy at 11 GeV/c and Cherenkov Ring Imaging at the SLD

    SciTech Connect

    Bienz, T.L.

    1990-07-01

    This thesis is divided into two sections, which describe portions of the data acquisition system and online software for the Cherenkov Ring Imaging Detector (CRID) for the SLD, and analyses of several low cross section strangeonium channels in data from the LASS spectrometer. The CRID section includes a description of the data acquisition system, determination of the preamplifier gain, and development of an online pulse finding algorithm based on deconvolution. Deconvolution uses knowledge of the preamplifier impulse response to aid in pulse finding. The algorithm is fast and shows good single pulse resolution and excellent double pulse resolution in preliminary tests. The strangeonium analyses are based on data from a 4.1 event/nanobarn exposure of the LASS spectrometer in K{sup {minus}}p interactions at 11 GeV/c, and include studies of {Lambda}{eta}{pi}{sup {plus}}{pi}{sup {minus}}, {Lambda}{Kappa}*{Kappa}*, and {Lambda}{phi}{phi}.

  5. Beyond VERITAS: High-Energy Gamma-Rays with the Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    Williams, David A.; CTA Consortium

    2016-01-01

    The Cherenkov Telescope Array (CTA) will be a new observatory for the study of very-high-energy gamma-ray sources, designed to achieve an order of magnitude improvement in sensitivity in the ~30 GeV to ~100 TeV energy band compared to currently operating instruments: VERITAS, MAGIC, and H.E.S.S. CTA will probe known sources with unprecedented sensitivity, angular resolution, and spectral coverage, while also detecting hundreds of new sources. CTA will provide access to data in this energy band to members of the wider astronomical community for the first time. The CTA Consortium will also conduct a number of Key Science Projects, including a Galactic Plane survey and a survey of one quarter of the extragalactic sky, creating legacy data sets that will also be available to the public. This presentation will describe how CTA will bring new opportunities for the solution of astrophysical puzzles.

  6. Readout electronics for the Wide Field of view Cherenkov/Fluorescence Telescope Array

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Zhang, S.; Zhang, Y.; Zhou, R.; Bai, L.; Zhang, J.; Huang, J.; Yang, C.; Cao, Z.

    2015-08-01

    The aim of the Large High Altitude Air Shower Observatory (LHAASO), supported by IHEP of the Chinese Academy of Sciences, is a multipurpose project with a complex detectors array for high energy gamma ray and cosmic ray detection. The Wide Field of view Cherenkov Telescope Array (WFCTA), as one of the components of the LHAASO project, aim to tag each primary particle that causes an air shower. The WFCTA is a portable telescope array used to detect cosmic ray spectra. The design of the readout electronics of the WFCTA is described in this paper Sixteen photomultiplier tubes (PMTs), together with their readout electronics are integrated into a single sub-cluster. To maintain good resolution and linearity over a wide dynamic range, a dual-gain amplification configuration on an analog board is used The digital board contains two 16channel 14-bit, 50 Msps analog-to-digital converters (ADC) and its power consumption, noise level, and relative deviation are all tested.

  7. Sensitivity of the High Altitude Water Cherenkov Experiment to observe Gamma-Ray Bursts

    NASA Astrophysics Data System (ADS)

    González, M. M.

    Ground based telescopes have marginally observed very high energy emission (>100GeV) from gamma-ray bursts(GRB). For instance, Milagrito observed GRB970417a with a significance of 3.7 sigmas over the background. Milagro have not yet observed TeV emission from a GRB with its triggered and untriggered searches or GeV emission with a triggered search using its scalers. These results suggest the need of new observatories with higher sensitivity to transient sources. The HAWC (High Altitute Water Cherenkov) observatory is proposed as a combination of the Milagro tecnology with a very high altitude (>4000m over see level) site. The expected HAWC sensitivity for GRBs is at least >10 times the Milagro sensitivity. In this work HAWC sensitivity for GRBs is discussed for different detector configurations such as altitude, distance between PMTs, depth under water of PMTs, number of PMTs required for a trigger, etc.

  8. Quantum Vavilov-Cherenkov radiation from shearing two transparent dielectric plates

    NASA Astrophysics Data System (ADS)

    Volokitin, A. I.; Persson, B. N. J.

    2016-01-01

    Using a fully relativistic theory we study the quantum Vavilov-Cherenkov radiation and quantum friction occurring during relative sliding of two transparent dielectric plates with the refractive index n . These phenomena occur above the threshold velocity vc=2 n c /(n2+1 ) . Close to the threshold velocity they are dominated by the contribution from s -polarized electromagnetic waves, which agrees with the approximate (relativistic) theory by Pendry [J. B. Pendry, J. Mod. Opt. 45, 2389 (1998), 10.1080/09500349808231248]. However, in the ultrarelativistic case (v →c ), the contributions from both polarizations are strongly enhanced in comparison with the approximate theory, and a new contribution occurs from the mixing of the electromagnetic waves with different polarizations. The numerical results are supplemented by an analytical treatment close to the threshold velocity and the light velocity.

  9. An autocollimator alignment system for a Schwarzschild-Couder Cherenkov telescope

    NASA Astrophysics Data System (ADS)

    Griffiths, S. T.; Kaaret, P.; Smith, E.

    2016-08-01

    We present a digital autocollimator which will be used in the alignment system of a prototype medium-sized telescope, which is part of the U.S. contribution to the Cherenkov Telescope Array (CTA). The Schwarzschild-Couder optics in the prototype telescope (which is currently under construction) requires the precise alignment of three components: the primary and secondary segmented mirrors, and the gamma-ray camera. The approximately 9 meter separation between the mirrors necessitates remote optical measurement. Our autocollimator will measure the angle of a segment in one mirror relative to the center of the other mirror with a precision better than 5 arcsec over a range of ±0.126 °. We present a detailed description of the instrument and describe its performance in the laboratory.

  10. Extended performance gas Cherenkov detector for gamma-ray detection in high-energy density experiments.

    PubMed

    Herrmann, H W; Kim, Y H; Young, C S; Fatherley, V E; Lopez, F E; Oertel, J A; Malone, R M; Rubery, M S; Horsfield, C J; Stoeffl, W; Zylstra, A B; Shmayda, W T; Batha, S H

    2014-11-01

    A new Gas Cherenkov Detector (GCD) with low-energy threshold and high sensitivity, currently known as Super GCD (or GCD-3 at OMEGA), is being developed for use at the OMEGA Laser Facility and the National Ignition Facility (NIF). Super GCD is designed to be pressurized to ≤400 psi (absolute) and uses all metal seals to allow the use of fluorinated gases inside the target chamber. This will allow the gamma energy threshold to be run as low at 1.8 MeV with 400 psi (absolute) of C2F6, opening up a new portion of the gamma ray spectrum. Super GCD operating at 20 cm from TCC will be ∼400 × more efficient at detecting DT fusion gammas at 16.7 MeV than the Gamma Reaction History diagnostic at NIF (GRH-6m) when operated at their minimum thresholds. PMID:25430303

  11. Performance of the Two Aerogel Cherenkov Detectors of the JLab Hall A Hadron Spectrometer

    SciTech Connect

    Marrone, Stefano; Wojtsekhowski, Bogdan; Acha Quimper, Armando; Cisbani, Evaristo; Coman, Marius; Cusanno, Francesco; De Jager, Cornelis; De Leo, Raffaele; Gao, Haiyan; Garibaldi, Franco; Higinbotham, Douglas; Iodice, Mauro; LeRose, John; Macchia, D.; Markowitz, Pete; Nappi, E.; Palmisano, F.; Urciuoli, Guido; van der Werf, I.; XIANG, Hong; Xiang, Hong; XIANG, Hong; Xiang, Hong; Zhu, Lingyan

    2009-01-01

    We report on the design and commissioning of two silica aerogel Cherenkov detectors with different refractive indices. In particular, extraordinary performance in terms of the number of detected photoelectrons was achieved through an appropriate choice of PMT type and reflector, along with some design considerations. After four years of operation, the number of detected photoelectrons was found to be noticeably reduced in both detectors as a result of contamination, yellowing, of the aerogel material. Along with the details of the set-up, we illustrate the characteristics of the detectors during different time periods and the probable causes of the contamination. In particular we show that the replacement of the contaminated aerogel and parts of the reflecting material has almost restored the initial performance of the detectors.

  12. Quantization of the electromagnetic field in nondispersive polarizable moving media above the Cherenkov threshold

    NASA Astrophysics Data System (ADS)

    Silveirinha, Mário G.

    2013-10-01

    We quantize the macroscopic electromagnetic field in a system of nondispersive polarizable bodies moving at constant velocities possibly exceeding the Cherenkov threshold. It is shown that in general the quantized system is unstable and neither has a ground state nor supports stationary states. The quantized Hamiltonian is written in terms of quantum harmonic oscillators associated with both positive and negative frequencies, such that the oscillators associated with symmetric frequencies are coupled by an interaction term that does not preserve the quantum occupation numbers. Moreover, in the linear regime the amplitudes of the fields may grow without limit provided the velocity of the moving bodies is enforced to be constant. This requires the application of an external mechanical force that effectively pumps the system.

  13. A proposed measurement of the reverse Cherenkov radiation effect in a metamaterial-loaded circular waveguide

    SciTech Connect

    Shchegolkov, Dmitry; Azad, Abul K; O' Hara, John F; Smirnova, Evgenya I

    2009-01-01

    The authors have recently proposed an experiment on verification of the Reverse Cherenkov Radiation (RCR) effect in a Left-Handed-Material-loaded waveguide. Applications of the RCR effect may range from novel higher-order-mode suppressors in microwave and millimeter-wave sources to improved particle detectors for satellite non-proliferation missions. The experimental configuration includes a circular waveguide filled with an artificial metamaterial with simultaneously negative permittivity and permeability, in which the electromagnetic wave with a frequency of 95 GHz will interact with an electron beam. They have demonstrated that for certain values of effective permittivity and permeability only the backward-propagating mode can be exited by the electron beam. At the conference they will present some newly developed metamaterial designs, which they plan to employ for producing the proper effective medium parameters for this experiment.

  14. Recent results of the forward ring imaging Cherenkov detector of the DELPHI experiment at LEP

    SciTech Connect

    Adam, W.; Albrecht, E. ); Augustinus, A. )

    1994-08-01

    The Forward Ring Imaging Cherenkov detector covers both end-cap regions of the DELPHI experiment at LEP in the polar angel 15[degree] < [theta] < 35[degree] and 145[degree] < [theta] < 165[degree]. The detector combines a layer of liquid C[sub 6]F[sub 14] and a volume of gaseous C[sub 4]F[sub 10] into a single assembly. Ultraviolet photons from both radiators are converted in a single plane of photosensitive Time Projection Chambers. Identification of charged particles is provided for momenta up to 40 GeV/c. The design of the detector is briefly described. The detector is now fully installed in DELPHI and has participated in the 1993 data taking. The overall performance will be presented together with the expectations from Monte Carlo simulations. Results close to design values are obtained.

  15. Diagnostics of Fast Electrons within Castor Tokamak by Means of a Modified Cherenkov-Type Probe

    SciTech Connect

    Zebrowski, J.; Jakubowski, L.; Sadowski, M. J.; Malinowski, K.; Jakubowski, M.; Weinzettl, V.; Stockel, J.; Peterka, M.

    2008-03-19

    The paper reports on experimental studies performed within the CASTOR tokamak, which was operated at IPP in Prague, Czech Republic, during the last experimental campaign carried out in autumn 2006. The main aim was to implement a new diagnostic technique for measurements of energetic (>80 keV) electrons within the tokamak edge plasma region. The technique was based on the use of a Cherenkov-type probe similar to the first prototype detector, which was tested during the previous experiments with the CASTOR device. In particular, the distributions of fast electrons in a standard scenario at different values of plasma current I{sub p}, and toroidal magnetic field B{sub T} are determined.

  16. An autocollimator alignment system for a Schwarzschild-Couder Cherenkov telescope

    NASA Astrophysics Data System (ADS)

    Griffiths, S. T.; Kaaret, P.; Smith, E.

    2016-04-01

    We present a digital autocollimator which will be used in the alignment system of a prototype medium-sized telescope, which is part of the U.S. contribution to the Cherenkov Telescope Array (CTA). The Schwarzschild-Couder optics in the prototype telescope (which is currently under construction) requires the precise alignment of three components: the primary and secondary segmented mirrors, and the gamma-ray camera. The approximately 9 meter separation between the mirrors necessitates remote optical measurement. Our autocollimator will measure the angle of a segment in one mirror relative to the center of the other mirror with a precision better than 5 arcsec over a range of ±0.126°. We present a detailed description of the instrument and describe its performance in the laboratory.

  17. Evaluation of Photo Multiplier Tube candidates for the Cherenkov Telescope Array

    NASA Astrophysics Data System (ADS)

    Mirzoyan, R.; Müller, D.; Hanabata, Y.; Hose, J.; Menzel, U.; Nakajima, D.; Takahashi, M.; Teshima, M.; Toyama, T.; Yamamoto, T.

    2016-07-01

    Photo Multiplier Tubes (PMTs) are the most wide spread detectors for fast, faint light signals. Six years ago, an improvement program for the PMT candidates for the Cherenkov Telescope Array (CTA) project was started with the companies Hamamatsu Photonics K.K. and Electron Tubes Enterprises Ltd. (ETE). For maximizing the performance of the CTA imaging cameras we need PMTs with outstanding good quantum efficiency, high photoelectron collection efficiency, short pulse width, very low afterpulse probability and transit time spread. We will report on the measurements of PMT R-12992-100 from Hamamatsu as their final product and the PMT D573KFLSA as one of the latest test versions from ETE as candidate PMTs for the CTA project.

  18. Extended performance gas Cherenkov detector for gamma-ray detection in high-energy density experimentsa)

    NASA Astrophysics Data System (ADS)

    Herrmann, H. W.; Kim, Y. H.; Young, C. S.; Fatherley, V. E.; Lopez, F. E.; Oertel, J. A.; Malone, R. M.; Rubery, M. S.; Horsfield, C. J.; Stoeffl, W.; Zylstra, A. B.; Shmayda, W. T.; Batha, S. H.

    2014-11-01

    A new Gas Cherenkov Detector (GCD) with low-energy threshold and high sensitivity, currently known as Super GCD (or GCD-3 at OMEGA), is being developed for use at the OMEGA Laser Facility and the National Ignition Facility (NIF). Super GCD is designed to be pressurized to ≤400 psi (absolute) and uses all metal seals to allow the use of fluorinated gases inside the target chamber. This will allow the gamma energy threshold to be run as low at 1.8 MeV with 400 psi (absolute) of C2F6, opening up a new portion of the gamma ray spectrum. Super GCD operating at 20 cm from TCC will be ˜400 × more efficient at detecting DT fusion gammas at 16.7 MeV than the Gamma Reaction History diagnostic at NIF (GRH-6m) when operated at their minimum thresholds.

  19. Cherenkov radiation dosimetry in water tanks - video rate imaging, tomography and IMRT & VMAT plan verification

    NASA Astrophysics Data System (ADS)

    Pogue, Brian W.; Glaser, Adam K.; Zhang, Rongxiao; Gladstone, David J.

    2015-01-01

    This paper presents a survey of three types of imaging of radiation beams in water tanks for comparison to dose maps. The first was simple depth and lateral profile verification, showing excellent agreement between Cherenkov and planned dose, as predicted by the treatment planning system for a square 5cm beam. The second approach was 3D tomography of such beams, using a rotating water tank with camera attached, and using filtered backprojection for the recovery of the 3D volume. The final presentation was real time 2D imaging of IMRT or VMAT treatments in a water tank. In all cases the match to the treatment planning system was within what would be considered acceptable for clinical medical physics acceptance.

  20. Monte Carlo validation experiments for the gas Cherenkov detectors at the National Ignition Facility and Omega

    SciTech Connect

    Rubery, M. S.; Horsfield, C. J.; Herrmann, H.; Kim, Y.; Mack, J. M.; Young, C.; Evans, S.; Sedillo, T.; McEvoy, A.; Caldwell, S. E.; Grafil, E.; Stoeffl, W.; Milnes, J. S.

    2013-07-15

    The gas Cherenkov detectors at NIF and Omega measure several ICF burn characteristics by detecting multi-MeV nuclear γ emissions from the implosion. Of primary interest are γ bang-time (GBT) and burn width defined as the time between initial laser-plasma interaction and peak in the fusion reaction history and the FWHM of the reaction history respectively. To accurately calculate such parameters the collaboration relies on Monte Carlo codes, such as GEANT4 and ACCEPT, for diagnostic properties that cannot be measured directly. This paper describes a series of experiments performed at the High Intensity γ Source (HIγS) facility at Duke University to validate the geometries and material data used in the Monte Carlo simulations. Results published here show that model-driven parameters such as intensity and temporal response can be used with less than 50% uncertainty for all diagnostics and facilities.