WorldWideScience

Sample records for cherenkov radiation

  1. Cooperative quasi-Cherenkov radiation

    CERN Document Server

    Anishchenko, S V

    2014-01-01

    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$/$cm$^2$ is obtained in simulations. In two- and three-wave diffraction cases, the peak intensity of cooperative radiation emitted at small and large angles to particle velocity is investigated as a function of the particle number in 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 expe...

  2. All-fiber femtosecond Cherenkov radiation source

    DEFF Research Database (Denmark)

    Liu, Xiaomin; Lægsgaard, Jesper; Møller, Uffe;

    2012-01-01

    -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...

  3. Cherenkov radiation threshold in random inhomogeneous media

    CERN Document Server

    Grichine, V M

    2009-01-01

    Cherenkov radiation in media with random inhomogeneities like aerogel or Earth atmosphere is discussed. The spectral-angular distribution of Cherenkov photons emitted by relativistic charged particle and averaged over the dielectric permittivity fluctuations shows angular broadening similarly to the case of media with the photon absorption. The broadening results in the smoothing of Cherenkov threshold, and therefore media with strong photon scattering have more extended dependence of Cherenkov light output on the particle speed. It can be potentially used for the particle identification

  4. All-fiber femtosecond Cherenkov radiation source.

    Science.gov (United States)

    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

  5. Flipping photons backward: reversed Cherenkov radiation

    Directory of Open Access Journals (Sweden)

    Hongsheng Chen

    2011-01-01

    Full Text Available Charged particles moving faster than light in a medium produce Cherenkov radiation. In traditional, positive index-of-refraction materials this radiation travels forward. Metamaterials, with negative indices of refraction, flip the radiation backward. This readily separates it from the particles, providing higher flexibility in photon manipulation and is useful for particle identification and counting. Here we review recent advances in reversed Cherenkov radiation research, including the first demonstration of backward emission. We also discuss the potential for developing new types of devices, such as ones that pierce invisibility cloaks.

  6. All-fiber femtosecond Cherenkov radiation source

    OpenAIRE

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

    2012-01-01

    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. ...

  7. Reverse surface-polariton cherenkov radiation

    Science.gov (United States)

    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.

  8. Characterization of coherent Cherenkov radiation source

    Energy Technology Data Exchange (ETDEWEB)

    Smirnov, A.V.

    2015-01-21

    Engineering formulae for calculation of peak, and spectral brightness of resonant long-range wakefield extractor are given. It is shown that the brightness is dominated by beam density in the slow wave structure and antenna gain of the outcoupling. Far field radiation patterns and brightness of circular and high aspect ratio planar radiators are compared. A possibility to approach diffraction limited brightness is demonstrated. The role of group velocity in designing of the Cherenkov source is analyzed. The approach can be applied for design and characterization of various structure-dominated sources (e.g., wakefield extractors with gratings or dielectrics, or FEL-Cherenkov combined sources) radiating into a free space using an antenna (in microwave to sub-mm wave regions). The high group velocity structures can be also effective as energy dechirpers and for diagnostics of microbunched relativistic electron beams.

  9. Recent progress in silica aerogel Cherenkov radiator

    CERN Document Server

    Tabata, Makoto; Kawai, Hideyuki; Kubo, Masato; Sato, Takeshi

    2012-01-01

    In this paper, we present recent progress in the development of hydrophobic silica aerogel as a Cherenkov radiator. In addition to the conventional method, the recently developed pin-drying method for producing high-refractive-index aerogels with high transparency was studied in detail. Optical qualities and large tile handling for crack-free aerogels were investigated. Sufficient photons were detected from high-performance aerogels in a beam test.

  10. Cherenkov radiation as a serendipitous phenomenon

    Science.gov (United States)

    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.

  11. The Cherenkov Radiation for Non-Trivial Systems; La Radiacion Cherenkov en Sistemas No Triviales

    Energy Technology Data Exchange (ETDEWEB)

    Grau Carles, A.

    2002-07-01

    The charge pathways and the dielectric properties of the medium are two essential aspects to be considered in the study of the emission of Cherenkov radiation. We described the evolution of the Cherenkov wavefront when the charges follow circular or helical pathways. Also we derive expressions for the refractive Index in different transparent media (solid, liquid or gas), focusing our attention on optically active plasmas. The optical analogies between the plasma and the birefringent crystals is studied in detail. Finally, we list some examples of plasmas, which can be considered emitters of Cherenkov radiation. (Author) 52 refs.

  12. Detection of atmospheric Cherenkov radiation using solar heliostat mirrors

    CERN Document Server

    Ong, R A

    1996-01-01

    The gamma-ray energy region between 20 and 250 GeV is largely unexplored. Ground-based atmospheric Cherenkov detectors offer a possible way to explore this region, but large Cherenkov photon collection areas are needed to achieve low energy thresholds. This paper discusses the development of a Cherenkov detector using the heliostat mirrors of a solar power plant as the primary collector. As part of this development, we built a prototype detector consisting of four heliostat mirrors and used it to record atmospheric Cherenkov radiation produced in extensive air showers created by cosmic ray particles.

  13. Constraint on ghost-free bigravity from gravitational Cherenkov radiation

    Science.gov (United States)

    Kimura, Rampei; Tanaka, Takahiro; Yamamoto, Kazuhiro; Yamashita, Yasuho

    2016-09-01

    We investigate gravitational Cherenkov radiation in a healthy branch of background solutions in the ghost-free bigravity model. In this model, because of the modification of dispersion relations, each polarization mode can possess subluminal phase velocities, and the gravitational Cherenkov radiation could be potentially emitted from a relativistic particle. In the present paper, we derive conditions for the process of the gravitational Cherenkov radiation to occur and estimate the energy emission rate for each polarization mode. We found that the gravitational Cherenkov radiation emitted even from an ultrahigh energy cosmic ray is sufficiently suppressed for the graviton's effective mass less than 100 eV, and the bigravity model with dark matter coupled to the hidden metric is therefore consistent with observations of high energy cosmic rays.

  14. Constraint on ghost-free bigravity from gravitational Cherenkov radiation

    CERN Document Server

    Kimura, Rampei; Yamamoto, Kazuhiro; Yamashita, Yasuho

    2016-01-01

    We investigate gravitational Cherenkov radiation in a healthy branch of background solutions in the ghost-free bigravity model. In this model, because of the modification of dispersion relations, each polarization mode can possess subluminal phase velocities, and the gravitational Cherenkov radiation could be potentially emitted from a relativistic particle. In the present paper, we derive conditions for the process of the gravitational Cherenkov radiation to occur and estimate the energy emission rate for each polarization mode. We found that the gravitational Cherenkov radiation emitted even from an ultrahigh energy cosmic ray is sufficiently suppressed for the graviton's effective mass less than $100\\,{\\rm eV}$, and the bigravity model with dark matter coupled to the hidden metric is therefore consistent with observations of high energy cosmic rays.

  15. X-ray diffraction radiation in conditions of Cherenkov effect

    NARCIS (Netherlands)

    Tishchenko, A. A.; Potylitsyn, A. P.; Strikhanov, M. N.

    2006-01-01

    X-ray diffraction radiation from ultra-relativistic electrons moving near an absorbing target is considered. The emission yield is found to increase significantly in conditions of Cherenkov effect. (c) 2006 Elsevier B.V. All rights reserved.

  16. The Cherenkov Radiation for Non-Trivial Systems

    International Nuclear Information System (INIS)

    The charge pathways and the dielectric properties of the medium are two essential aspects to be considered in the study of the emission of Cherenkov radiation. We described the evolution of the Cherenkov wavefront when the charges follow circular or helical pathways. Also we derive expressions for the refractive Index in different transparent media (solid, liquid or gas), focusing our attention on optically active plasmas. The optical analogies between the plasma and the birefringent crystals is studied in detail. Finally, we list some examples of plasmas, which can be considered emitters of Cherenkov radiation. (Author) 52 refs

  17. Optical and radiographical characterization of silica aerogel for Cherenkov radiator

    CERN Document Server

    Tabata, Makoto; Hatakeyama, Yoshikiyo; Kawai, Hideyuki; Morita, Takeshi; Nishikawa, Keiko

    2012-01-01

    We present optical and X-ray radiographical characterization of silica aerogels with refractive index from 1.05 to 1.07 for a Cherenkov radiator. A novel pin-drying method enables us to produce highly transparent hydrophobic aerogels with high refractive index by shrinking wet-gels. In order to investigate the uniformity in the density (i.e., refractive index) of an individual aerogel monolith, we use the laser Fraunhofer method, an X-ray absorption technique, and Cherenkov imaging by a ring imaging Cherenkov detector in a beam test. We observed an increase in density at the edge of the aerogel tiles, produced by pin-drying.

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

    Science.gov (United States)

    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

  19. Characteristics of Cherenkov Radiation in Naturally Occuring Ice

    CERN Document Server

    Mikkelsen, R E; Uggerhøj, U I; Klein, S R

    2016-01-01

    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. Being located at the Antarctica, this detector makes use of the naturally occuring 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 ap...

  20. Counting Extra Dimensions Magnetic Cherenkov Radiation from High Energy Neutrinos

    CERN Document Server

    Domokos, Gabor K; Kövesi-Domokos, S; Erdas, Andrea

    2003-01-01

    In theories which require a space of dimension d > 4, there is a natural mechanism of suppressing neutrino masses: while Standard Model fields are confined to a 3-brane, right handed neutrinos live in the bulk. Due to Kaluza-Klein excitations, the effective magnetic moments of neutrinos are enhanced. The effective magnetic moment is a monotonically growing function of the energy of the neutrino: consequently, high energy neutrinos can emit observable amounts of magnetic Cherenkov radiation. By observing the energy dependence of the magnetic Cherenkov radiation, one may be able to determine the number of compactified dimensions.

  1. Detection of atmospheric Cherenkov radiation using solar heliostat mirrors

    Science.gov (United States)

    Ong, R. A.; Bhattacharya, D.; Covault, C. E.; Dixon, D. D.; Gregorich, D. T.; Hanna, D. S.; Oser, S.; Québert, J.; Smith, D. A.; Tümer, O. T.; Zych, A. D.

    1996-10-01

    There is considerable interest world-wide in developing large area atmospheric Cherenkov detectors for ground-based gamma-ray astronomy. This interest stems, in large part, from the fact that the gamma-ray energy region between 20 and 250 GeV is unexplored by any experiment. Atmospheric Cherenkov detectors offer a possible way to explore this region, but large photon collection areas are needed to achieve low energy thresholds. We are developing an experiment using the heliostat mirrors of a solar power plant as the primary collecting element. As part of this development, we built a detector using four heliostat mirrors, a secondary Fresnel lens, and a fast photon detection system. In November 1994, we used this detector to record atmospheric Cherenkov radiation produced by cosmic ray particles showering in the atmosphere. The detected rate of cosmic ray events was consistent with an energy threshold near 1 TeV. The data presented here represent the first detection of atmospheric Cherenkov radiation using solar heliostats viewed from a central tower.

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

    Science.gov (United States)

    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.

  3. A Resolution to Cherenkov-like Radiation of OPERA Neutrinos

    CERN Document Server

    Oda, Ichiro

    2011-01-01

    The OPERA collabotation has reported evidence of superluminal neutrinos with a mean energy 17.5 GeV ranging up to 50 GeV. However, the superluminal interpretation of the OPERA results has been recently refuted theoretically by Cherenkov-like radiation. We discuss a loophole of this argument from the kinematical viewpoint and find it possible to avoid the Cherenkov-like radiation of the OPERA neutrinos. The key idea of our argument is to admit the fact that the neutrinos travel faster than the observed speed of light while they do slower than the true speed of light in vacuum so strictly speaking they are not superluminal but subluminal. Moreover, we present a model where these two velocities of light can be constructed by taking account of influences from dark matters near the earth.

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

    DEFF Research Database (Denmark)

    Bache, Morten; Bang, Ole; Zhou, Binbin;

    2010-01-01

    -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 = 0.95–1.45 μm, and is located in the regime λ = 1.5–3.5 μm. For shorter pump wavelengths, the phase...

  5. Vavilov-Cherenkov radiation in dispersive medium

    International Nuclear Information System (INIS)

    We analyze how the frequency dependence of the electric permittivity ε affects the electromagnetic field radiated by a point charge uniformly moving in medium. It turns out that a moving charge radiates at every velocity when the standard parametrization of ε is chosen. The space distribution of this radiation exhibits rapid oscillations behind the moving charge. They differ drastically for the charge velocity below and above some critical velocity νc defined by the medium properties and independent of frequency. It turns out that for νc the radiation flux is maximal in the narrow cone lying behind the moving charge with the axis coinciding with the charge velocity. The influence of the imaginary part of electric permittivity ε on the electromagnetic field radiated by a moving charge is also studied. It turns out that switching on the imaginary part of ε results in a considerable reduction of the intensity radiation for νc and in attenuation of secondary maxima of the radiation intensity for νc. This consideration may be useful for the interpretation of experiments recently discussed in physical literature

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

    Science.gov (United States)

    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

  7. Coherent Cherenkov radiation as an intense THz source

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Hayward, J P [University of Tennessee, Knoxville (UTK); Hobbs, C. L. [University of Tennessee, Knoxville (UTK); Bell, Zane W [ORNL; Boatner, Lynn A [ORNL; Johnson, Rose E [ORNL; Ramey, Joanne Oxendine [ORNL; Jellison Jr, Gerald Earle [ORNL; Lillard, Cole R [ORNL; Ramey, Lucas A [ORNL

    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.

  9. Relativistic Cherenkov radiation in a magneto-dielectric media

    Directory of Open Access Journals (Sweden)

    2016-09-01

    Full Text Available In this paper, relativistic Cherenkov radiation was studied in a 3-D magneto-dielectric medium. Electric permittivity and magnetic permeability of the medium as functions of frequency, are assumed to satisfy Kramers- Kronig equations. A new interaction Hamiltonian, which is different from Hamiltonian term in non-relativistic state, was introduced by the quantized vector potential field and particle field operator obtained from the second quantization method. The rate of electron energy dissipation was calculated using Fermi’s golden rule.

  10. The HERMES dual-radiator ring imaging Cherenkov detector

    CERN Document Server

    Akopov, N; Bailey, K; Bernreuther, S; Bianchi, N; Capitani, G P; Carter, P; Cisbani, E; De Leo, R; De Sanctis, E; De Schepper, D; Dzhordzhadze, V; Filippone, B W; Frullani, S; Garibaldi, F; Hansen, J O; Hommez, B; Iodice, M; Jackson, H E; Jung, P; Kaiser, R; Kanesaka, J; Kowalczyk, R; Lagamba, L; Maas, A; Muccifora, V; Nappi, E; Negodaeva, K; Nowak, Wolf-Dieter; O'Connor, T; O'Neill, T G; Potterveld, D H; Ryckbosch, D; Sakemi, Y; Sato, F; Schwind, A; Shibata, T A; Suetsugu, K; Thomas, E; Tytgat, M; Urciuoli, G M; Van De Kerckhove, K; Van De Vyver, R; Yoneyama, S; Zhang, L F; Zohrabyan, H G

    2002-01-01

    The construction and use of a dual radiator Ring Imaging Cherenkov (RICH) detector is described. This instrument was developed for the HERMES experiment at DESY which emphasises measurements of semi-inclusive deep-inelastic scattering. It provides particle identification for pions, kaons, and protons in the momentum range from 2 to 15 GeV, which is essential to these studies. The instrument uses two radiators, C sub 4 F sub 1 sub 0 , a heavy fluorocarbon gas, and a wall of silica aerogel tiles. The use of aerogel in a RICH detector has only recently become possible with the development of clear, large, homogeneous and hydrophobic aerogel. A lightweight mirror was constructed using a newly perfected technique to make resin-coated carbon-fiber surfaces of optical quality. The photon detector consists of 1934 photomultiplier tubes (PMT) for each detector half, held in a soft steel matrix to provide shielding against the residual field of the main spectrometer magnet.

  11. The HERMES dual-radiator ring imaging Cherenkov detector

    International Nuclear Information System (INIS)

    The construction and use of a dual radiator Ring Imaging Cherenkov (RICH) detector is described. This instrument was developed for the HERMES experiment at DESY which emphasises measurements of semi-inclusive deep-inelastic scattering. It provides particle identification for pions, kaons, and protons in the momentum range from 2 to 15 GeV, which is essential to these studies. The instrument uses two radiators, C4F10, a heavy fluorocarbon gas, and a wall of silica aerogel tiles. The use of aerogel in a RICH detector has only recently become possible with the development of clear, large, homogeneous and hydrophobic aerogel. A lightweight mirror was constructed using a newly perfected technique to make resin-coated carbon-fiber surfaces of optical quality. The photon detector consists of 1934 photomultiplier tubes (PMT) for each detector half, held in a soft steel matrix to provide shielding against the residual field of the main spectrometer magnet

  12. Intense Cherenkov-type terahertz electromagnetic radiation from ultrafast laser-plasma interaction

    Institute of Scientific and Technical Information of China (English)

    Hu Qiang-Lin; Liu Shi-Bing; Li Wei

    2008-01-01

    A Cherenkov-type terahertz electromagnetic radiation is revealed, which results efficiently from the collective effects in the time-domain of ultrafast pulsed electron current produced by ultrafast intense laser-plasma interaction.The emitted pulse waveform and spectrum, and the dependence of laser pulse parameters on the structure of the radiation field are investigated numerically. The condition of THz radiation generation in this regime and Cherenkov geometry of the radiation field are studied analytically.

  13. Vacuum Cherenkov radiation and bremsstrahlung from disformal couplings

    Science.gov (United States)

    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.

  14. Vacuum Cherenkov radiation and bremsstrahlung from disformal couplings

    CERN Document Server

    van de Bruck, Carsten; Morrice, Jack

    2016-01-01

    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.

  15. CPT-Violating, Massive Photons and Cherenkov Radiation

    CERN Document Server

    Colladay, Don

    2016-01-01

    CPT-Violating photons are well-known to have problems with energy positivity in certain cases and therefore have not been convincingly quantized to date. We find that by adding a small mass term, consistent with experimental bounds, the theory can be regulated and allows for a consistent covariant quantization procedure. This new framework is applied to a consistent quantum calculation of vacuum Cherenkov radiation rates. These rates turn out to be largely independent of the mass of the photon regulator used. In the physical regime, accessible by ultra high energy cosmic rays, the behavior of the rate is proportional to the square of the CPT-violating parameter and is not realistically observable.

  16. Angular width of Cherenkov radiation with inclusion of multiple scattering: an path-integral approach

    CERN Document Server

    Zheng, Jian

    2016-01-01

    Visible Cherenkov radiation can offers a method of the measurement of the velocity of a 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 and the analytical expressions are presented. The condition that multiple scattering process dominates the angular distribution is obtained.

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

    Science.gov (United States)

    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.

  18. Cherenkov Radiation from $e^+e^-$ Pairs and Its Effect on $\

    CERN Document Server

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

    2005-01-01

    We calculate the Cherenkov radiation from an $e^+e^-$ 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.

  19. Quenching the scintillation in CF{sub 4} Cherenkov gas radiator

    Energy Technology Data Exchange (ETDEWEB)

    Blake, T. [Department of Physics, University of Warwick, Coventry (United Kingdom); D' Ambrosio, C. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Easo, S. [STFC Rutherford Appleton Laboratory, Didcot (United Kingdom); European Organization for Nuclear Research (CERN), Geneva (Switzerland); Eisenhardt, S. [School of Physics and Astronomy, University of Edinburgh, Edinburgh (United Kingdom); Fitzpatrick, C. [Ecole Polytechnique Fédérale de Lausanne (EPFL), Lausanne (Switzerland); Forty, R.; Frei, C. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Gibson, V. [Cavendish Laboratory, University of Cambridge, Cambridge (United Kingdom); Gys, T. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Harnew, N.; Hunt, P. [Department of Physics, University of Oxford, Oxford (United Kingdom); Jones, C.R. [Cavendish Laboratory, University of Cambridge, Cambridge (United Kingdom); Lambert, R.W. [Nikhef National Institute for Subatomic Physics and VU University Amsterdam, Amsterdam (Netherlands); Matteuzzi, C. [Sezione INFN di Milano Bicocca, Milano (Italy); Muheim, F. [School of Physics and Astronomy, University of Edinburgh, Edinburgh (United Kingdom); Papanestis, A., E-mail: antonis.papanestis@stfc.ac.uk [STFC Rutherford Appleton Laboratory, Didcot (United Kingdom); European Organization for Nuclear Research (CERN), Geneva (Switzerland); Perego, D.L. [Sezione INFN di Milano Bicocca, Milano (Italy); Università di Milano Bicocca, Milano (Italy); Piedigrossi, D. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Plackett, R. [Imperial College London, London (United Kingdom); Powell, A. [Department of Physics, University of Oxford, Oxford (United Kingdom); and others

    2015-08-11

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

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

    Science.gov (United States)

    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.

  1. Cherenkov Radiation with Massive, CPT-violating Photons

    CERN Document Server

    Colladay, Don; Potting, Robertus

    2016-01-01

    The source of CPT-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 $k_{AF}^\\mu$. These Lorentz- and CPT-violating photons have well-known theoretical issues that arise from missing states at low momenta when $k_{AF}^\\mu$ 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 CPT-preserving case by using the St\\"uckelberg 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 $k_{AF}^\\mu$, and find a radiation rate at high energies that has a contribution that does n...

  2. A module of silicon photo-multipliers for detection of Cherenkov radiation

    Science.gov (United States)

    Korpar, Samo; Chagani, Hassan; Dolenec, Rok; Križan, Peter; Pestotnik, Rok; Stanovnik, Aleš

    2010-02-01

    A module, consisting of 64 (=8×8) Hamamatsu MPPC S10362-11-100P silicon photomultipliers, has been constructed and tested as a position sensitive detector of Cherenkov photons. In order to increase the efficiency, i.e. the effective surface over which Cherenkov light is collected, we have manufactured and tested suitable light guides. In addition to the increase in efficiency, it is shown that such light guides considerably improve the signal-to-noise ratio. The results of our measurements indicate that the performance of such a Cherenkov counter with aerogel radiator could meet the requirements of particle identification at the foreseen upgraded Belle detector.

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

    Science.gov (United States)

    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.

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

    CERN Document Server

    Ivanov, I P; Zaytsev, V A

    2016-01-01

    We present the 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.

  5. About Modeling the Excitation Conditions of Cherenkov and Diffraction Radiations in Periodic Metal-dielectric Structures

    Directory of Open Access Journals (Sweden)

    G.S. Vorobjov

    2015-06-01

    Full Text Available General procedure for modeling the excitation conditions of Cherenkov and diffraction radiations in periodic metal-dielectric structures is described. It is based on the representation of the electron beam space-charge wave in the form of a dielectric waveguide surface-wave. On the experimental facility of millimeter-wave the basic modes of excitation conditions of spatial harmonics of the Cherenkov and diffraction radiations are simulated. The method is tested by comparing the numerical analysis and experimental results on the layout of the device of the orotron type - generator of diffraction radiation.

  6. Spectral dependence of angular distribution halfwidths of Vavilov-Cherenkov radiation

    International Nuclear Information System (INIS)

    Angular distributions of Vavilov-Cherenkov radiation have been measured. This radiaiton is excited during 210 keV electron propagation in a mica 2.5 mm thick target in a spectral range from 2500 up to 5000 A. A formula for diffraction halfwidth of angular distribution has been derived, its applicability limits are pointed out. Experimental halfwidth agrees with the calculated ones. The deviation of angular distribution maximum from Vavilov-Cherenkov radiation angle is analyzed. This deviation is due to radiator boundaries and multiple scattering of electrons

  7. Cherenkov and parametric (quasi-Cherenkov) radiation from relativistic charged particles moving in crystals formed by metallic wires

    CERN Document Server

    Baryshevsky, Vladimir

    2016-01-01

    Until recently, the interaction of electromagnetic waves with crystals built from parallel metallic wires (wire media) was analyzed in the approximation of isotropic scattering of the electromagnetic wave by a single wire. However, if the wires are thick (kR~1), electromagnetic wave scattering by a wire is anisotropic, i.e., the scattering amplitude depends on the scattering angle. In this work, we derive the equations that describe diffraction of electromagnetic waves and spontaneous emission of charged particles in wire media, and take into account the angular dependence of scattering amplitude. Numerical solutions of these equations show that the radiation intensity increases as the wire radius is increased and achieves its maximal value in the range kR~1. The case when the condition kR~1 is fulfilled in the THz frequency range is considered in detail. The calculations show that the instantaneous power of Cherenkov and parametric (quasi-Cherenkov) radiations from electron bunches in the crystal can be tens...

  8. A Cherenkov Radiation Detector with High Density Aerogels

    CERN Document Server

    Cremaldi, Lucien; Sonnek, Peter; Summers, Donald J; Reidy, Jim

    2009-01-01

    We have designed a threshold Cherenkov detector at the Rutherford-Appleton Laboratory to identify muons with momenta between 230 and 350 MeV/c. We investigated the properties of three aerogels for the design. The nominal indexes of refraction were n = 1.03, 1.07, 1.12, respectively. Two of the samples are of high density aerogel not commonly used for Cherenkov light detection. We present results of an examination of some optical properties of the aerogel samples and present basic test beam results.

  9. Particle Identification: Time-of-Flight, Cherenkov and Transition Radiation Detectors - Particle Detectors and Detector Systems

    CERN Document Server

    Ullaland, O

    2011-01-01

    Particle Identification: Time-of-Flight, Cherenkov and Transition Radiation Detectors in 'Particle Detectors and Detector Systems', part of 'Landolt-Börnstein - Group I Elementary Particles, Nuclei and Atoms: Numerical Data and Functional Relationships in Science and Technology, Volume 21B1: Detectors for Particles and Radiation. Part 1: Principles and Methods'. This document is part of Part 1 'Principles and Methods' of Subvolume B 'Detectors for Particles and Radiation' of Volume 21 'Elementary Particles' of Landolt-Börnstein - Group I 'Elementary Particles, Nuclei and Atoms'. It contains the Section '3.3 Particle Identification: Time-of-Flight, Cherenkov and Transition Radiation Detectors' of Chapter '3 Particle Detectors and Detector Systems' with the content: 3.3 Particle Identification: Time-of-Flight, Cherenkov and Transition Radiation Detectors 3.3.1 Introduction 3.3.2 Time of Flight Measurements 3.3.2.1 Scintillator hodoscopes 3.3.2.2 Parallel plate ToF detectors 3.3.3 Cherenkov Radiation 3.3.3.1 ...

  10. A Cherenkov imager for the charge measurement of the elements of nuclear cosmic radiation

    International Nuclear Information System (INIS)

    A Cherenkov imager, CHERCAM (Cherenkov Camera) has been designed and built for the CREAM (Cosmic Ray Energetics and Mass) balloon-borne experiment. The instrument will perform charge measurements of nuclear cosmic-ray over a range extending from proton to iron in the energy domain from 1010 to 1015 eV. This work has focused on the development of CHERCAM by creating a simulation of the detector and on the aerogel plan characterization for the radiator. But it has also expanded on the technical aspects of the construction of the detector and its various tests, as well as the development of calibration software and data analysis. (author)

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

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Jarvis, Lesley A., E-mail: Lesley.a.jarvis@hitchcock.org [Department of Medicine, Geisel School of Medicine at Dartmouth College, Hanover, New Hampshire (United States); Norris Cotton Cancer Center at the Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire (United States); Zhang, Rongxiao [Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire (United States); Gladstone, David J. [Department of Medicine, Geisel School of Medicine at Dartmouth College, Hanover, New Hampshire (United States); Norris Cotton Cancer Center at the Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire (United States); Jiang, Shudong [Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire (United States); Hitchcock, Whitney [Geisel School of Medicine at Dartmouth College, Hanover, New Hampshire (United States); Friedman, Oscar D.; Glaser, Adam K.; Jermyn, Michael [Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire (United States); Pogue, Brian W. [Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire (United States); Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire (United States)

    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.

  13. Influence of thermal fluctuations on Cherenkov radiation from fluxons in dissipative Josephson systems

    DEFF Research Database (Denmark)

    Antonov, A. A.; Pankratov, A. L.; Yulin, A. V.;

    2000-01-01

    The nonlinear dynamics of fluxons in Josephson systems with dispersion and thermal fluctuations is analyzed using the "quasiparticle" approach to investigate the influence of noise on the Cherenkov radiation effect. Analytical expressions for the stationary amplitude of the emitted radiation...... and its spectral distribution have been obtained in an annular geometry. It is demonstrated that noise reduces the amplitude of the radiated wave and broadens its spectrum. The effect of the radiated wave on the fluxon dynamics leads to a considerably smaller linewidth than observed in the usual flux flow...... oscillator. A resonant behavior of both the mean amplitude and the linewidth as functions of bias current is found. The obtained results enable an optimization of the main parameters (power, tunability, and linewidth) of practical mm- and sub-mm wave Cherenkov flux flow oscillators....

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

    International Nuclear Information System (INIS)

    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.

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

    Science.gov (United States)

    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.

  16. R and D on high momentum particle identification with a pressurized Cherenkov radiator

    Energy Technology Data Exchange (ETDEWEB)

    Agócs, A.G. [Wigner RCP of the HAS, Budapest (Hungary); Barile, F. [INFN Sezione di Bari and Universit´a degli Studi di Bari, Dipartimento Interateneo di Fisica M. Merlin, Bari (Italy); Barnaföldi, G.G. [Wigner RCP of the HAS, Budapest (Hungary); Bellwied, R. [University of Houston, Houston (United States); Bencédi, G.; Bencze, G.; Berényi, D.; Boldizsár, L. [Wigner RCP of the HAS, Budapest (Hungary); Chattopadhyay, S. [Saha Institute of Nuclear Physics, Kolkata (India); Chinellato, D.D. [University of Houston, Houston (United States); Cindolo, F. [University of Salerno, Salerno (Italy); Cossyleon, K. [Chicago State University, Chicago, IL (United States); Das, D.; Das, K.; Das-Bose, L. [Saha Institute of Nuclear Physics, Kolkata (India); De Cataldo, G.; Di Bari, D. [INFN Sezione di Bari and Universit´a degli Studi di Bari, Dipartimento Interateneo di Fisica M. Merlin, Bari (Italy); Di Mauro, A. [CERN, CH1211 Geneva 23 (Switzerland); Futó, E. [Wigner RCP of the HAS, Budapest (Hungary); Garcia-Solis, E. [Chicago State University, Chicago, IL (United States); and others

    2014-12-01

    We report on the R and D results for a Very High Momentum Particle Identification (VHMPID) detector, which was proposed to extend the charged hadron track-by-track identification in the momentum range from 5 to 25 GeV/c in the ALICE experiment at CERN. It is a RICH detector with focusing geometry using pressurized perfluorobutane (C{sub 4}F{sub 8}O) as a Cherenkov radiator. A MWPC with a CsI photocathode was investigated as the baseline option for the photon detector. The results of beam tests performed on RICH prototypes using both liquid C{sub 6}F{sub 14} radiator (in proximity focusing geometry for reference measurements) and pressurized C{sub 4}F{sub 8}O gaseous radiator will be shown in this paper. In addition, we present studies of a CsI based gaseous photon detector equipped with a MWPC having an adjustable anode–cathode gap, aiming at the optimization of the chamber layout and performance in the detection of single photoelectrons. - Highlights: • Pressurized and heated C{sub 4}F{sub 8}O was used as Cherenkov radiator gas. • A Cherenkov angle resolution of 1.5 mrad was achieved. • The separation of electrons, pions, and kaons in a large momentum range is shown.

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

    Science.gov (United States)

    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

  18. Development of new photon detection device for Cherenkov and fluorescence radiation

    Science.gov (United States)

    Aramo, C.; Ambrosio, A.; Ambrosio, M.; Battiston, R.; Castrucci, P.; Cilmo, M.; De Crescenzi, M.; Fiandrini, E.; Guarino, F.; Grossi, V.; Maddalena, P.; Nappi, E.; Passacantando, M.; Pignatel, G.; Santucci, S.; Scarselli, M.; Tinti, A.; Valentini, A.

    2013-06-01

    Recent progress on the development of a new solid state detector allowed the use of finely pixelled photocathodes obtained from silicon semiconductors. SiPM detectors seem to be an ideal tool for the detection of Cherenkov and fluorescence light in spite of their not yet resolved criticism for operating temperature and intrinsic noise. The main disadvantage of SiPM in this case is the poor sensitivity in the wavelength range 300-400 nm, where the Cherenkov light and fluorescence radiation are generated. We report on the possibility to realize a new kind of pixelled photodetector based on the use of silicon substrate with carbon nanotube compounds, more sensitive to the near UV radiation. Also if at the very beginning, the development of such detector appears very promising and useful for astroparticle physics, both in the ground based arrays and in the space experiments. The detectors are ready to be operated in conditions of measurements without signal amplification.

  19. Photonic chip based optical frequency comb using soliton induced Cherenkov radiation

    CERN Document Server

    Brasch, Victor; Geiselmann, Michael; Lihachev, Grigoriy; Pfeiffer, Martin H P; Gorodetsky, Michael L; Kippenberg, Tobias J

    2014-01-01

    By continuous wave pumping of a dispersion engineered, planar silicon nitride microresonator, continuously circulating, sub-30fs short temporal dissipative solitons are generated, that correspond to pulses of 6 optical cycles and constitute a coherent optical frequency comb in the spectral domain. Emission of soliton induced Cherenkov radiation caused by higher order dispersion broadens the spectral bandwidth to 2/3 of an octave, sufficient for self referencing, in excellent agreement with recent theoretical predictions and the broadest coherent microresonator frequency comb generated to date. The ability to preserve coherence over a broad spectral bandwidth using soliton induced Cherenkov radiation marks a critical milestone in the development of planar optical frequency combs, enabling on one hand application in e.g. coherent communications, broadband dual comb spectroscopy and Raman spectral imaging, while on the other hand significantly relaxing dispersion requirements for broadband microresonator frequen...

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

    International Nuclear Information System (INIS)

    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/. (paper)

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

    Science.gov (United States)

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

    International Nuclear Information System (INIS)

    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.

  3. Coherent Cherenkov radiation and laser oscillation in a photonic crystal

    CERN Document Server

    Denis, T; Lee, J H H; van der Meer, R; Strooisma, A; van der Slot, P J M; Vos, W L; Boller, K J

    2016-01-01

    We demonstrate that photonic crystals can be used to generate powerful and highly coherent laser radiation when injecting a beam of free electrons. Using theoretical investigations we present the startup dynamics and coherence properties of such laser, in which gain is provided by matching the optical phase velocity in the photonic crystal to the velocity of the electron beam.

  4. Design optimization of the proximity focusing RICH with dual aerogel radiator using a maximum-likelihood analysis of Cherenkov rings

    Science.gov (United States)

    Pestotnik, R.; Križan, P.; Korpar, S.; Iijima, T.

    2008-09-01

    The use of a sequence of aerogel radiators with different refractive indices in a proximity focusing Cherenkov ring imaging detector has been shown to improve the resolution of the Cherenkov angle. In order to obtain further information on the capabilities of such a detector, a maximum-likelihood analysis has been performed on simulated data, with the simulation being appropriate for the upgraded Belle detector. The results show that by using a sequence of two aerogel layers with different refractive indices, the K/π separation efficiency is improved in the kinematic region above 3 GeV/ c. In the low momentum region, the focusing configuration (with n1 and n2 chosen such that the Cherenkov rings from different aerogel layers at 4 GeV/ c overlap) shows a better performance than the defocusing one (where the two Cherenkov rings are well separated).

  5. Generalized Super-Cherenkov radiations in nuclear and hadronic media

    International Nuclear Information System (INIS)

    Generalized Super-Cerenkov Radiations (SCR), as well as their SCR-signatures are investigated and classified. Two general SCR-coherence conditions are found as two natural extremes of the same spontaneous particles decay in (dielectric, nuclear or hadronic) media. The main results on the quantum theory of the SCR-phenomena as well as the results of the first experimental test of the super-coherence conditions, obtained by using the experimental data from BNL, are presented. The new concepts such as: SCR-gluons, SCR-W-bosons and SCR-Z-bosons, all three suggested by elementary particle classification, are introduced. The gluonic Super-Cerenkov-like radiation, first introduced here, is schematically described. The interpretation of some recent RHIC results as signature of the SCR-gluons is suggested. (author(

  6. Cherenkov imaging during volumetric modulated arc therapy for real-time radiation beam tracking and treatment response monitoring

    Science.gov (United States)

    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.

  7. Parametric (quasi-Cherenkov) cooperative radiation produced by electron bunches in natural or photonic crystals

    CERN Document Server

    Anishchenko, S V

    2013-01-01

    We use numerical modeling to study the features of parametric (quasi-Cherenkov) cooperative radiation arising when an electron bunch passes through a crystal (natural or artificial) under the conditions of dynamical diffraction of electromagnetic waves in the presence of shot noise. It is shown that in both Laue and Bragg diffraction cases, parametric radiation consists of two strong pulses: one emitted at small angles with respect to the particle velocity direction and the other emitted at large angles to it. Under Bragg diffraction conditions, the intensity of parametric radiation emitted at small angles to the particle velocity direction reaches saturation at sufficiently smaller number of particles than the intensity of parametric radiation emitted at large angles. Under Laue diffraction conditions, every pulse contains two strong peaks, which are associated with the emission of electromagnetic waves at the front and back ends of the bunch. The presence of noise causes a chaotic signal in the interval bet...

  8. Vacuum Cherenkov radiation and photon decay rates from generic Lorentz Invariance Violation

    CERN Document Server

    Martínez-Huerta, H

    2016-01-01

    Among the most studied approaches to introduce the breaking of Lorentz symmetry, the generic approach is one of the most frequently used for phenomenology, it converges on the modification of the free particle dispersion relation. Using this approach in the photon sector, we have calculated the squared probability amplitude for vacuum Cherenkov radiation and photon decay by correcting the QED coupling at tree level and first order in LIV parameters. For the lower order energy correction we calculate the emission and decay rate for each process.

  9. On high frequency Cherenkov-type radiation in pulsar magnetospheric electron-positron plasma

    CERN Document Server

    Machabeli, George

    2014-01-01

    Emission process of a charged particle propagating in a medium with a curved magnetic field is considered. This mechanism combines features of conventional Cherenkov and curvature emission. Thus, presence of a medium with the index of refraction larger than the unity is essential for the emission. In the present paper the generation of high frequency radiation by the mentioned mechanism is considered. The generated waves are vacuum-like electromagnetic waves and may leave the medium directly. Consequently, this emission mechanism may be important for the problem of pulsar X-ray and gamma-ray emission generation.

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

    Energy Technology Data Exchange (ETDEWEB)

    Andreozzi, Jacqueline M., E-mail: Jacqueline.M.Andreozzi.th@dartmouth.edu; Glaser, Adam K. [Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755 (United States); Zhang, Rongxiao [Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755 (United States); Jarvis, Lesley A.; Gladstone, David J. [Department of Medicine, Geisel School of Medicine and Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03766 (United States); Pogue, Brian W., E-mail: Brian.W.Pogue@dartmouth.edu [Thayer School of Engineering and Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755 (United States)

    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

  11. Rapid screening of {sup 90}Sr activity in water and milk samples using Cherenkov radiation

    Energy Technology Data Exchange (ETDEWEB)

    Stamoulis, K.C. [Archaeometry Center, University of Ioannina, 45110 Ioannina (Greece)]. E-mail: kstamoul@cc.uoi.gr; Ioannides, K.G. [Archaeometry Center, University of Ioannina, 45110 Ioannina (Greece); Nuclear Physics Laboratory, University of Ioannina, 45110 Ioannina (Greece); Karamanis, D.T. [Nuclear Physics Laboratory, University of Ioannina, 45110 Ioannina (Greece); Patiris, D.C. [Nuclear Physics Laboratory, University of Ioannina, 45110 Ioannina (Greece)

    2007-07-01

    A method for screening {sup 90}Sr in milk samples is proposed. This method is based on a liquid scintillation technique taking advantage of Cherenkov radiation, which is produced in a liquid medium and then detected by the photomultipliers of a Liquid Scintillation Counter (LSC). Twenty millilitres of water and milk samples spiked with various concentrations of {sup 90}Sr/{sup 90}Y in equilibrium were added in plastic vials and then were measured with an LSC (TriCarb 3170 TR/SL). The derived efficiencies were 49% for water samples and 14% for milk samples. The detection limit was 470 mBq L{sup -1} {sup 90}Sr for water, without any pretreatment. Milk contains potassium, which also produces Cherenkov radiation due to the presence of {sup 40}K. For this reason, the interference of {sup 40}K in the measurements of {sup 90}Sr in milk samples was also investigated. The detection limit for milk was 1.7 Bq L{sup -1} {sup 90}Sr.

  12. Development of new photon detection device for Cherenkov and fluorescence radiation

    Directory of Open Access Journals (Sweden)

    Tinti A.

    2013-06-01

    Full Text Available Recent progress on the development of a new solid state detector allowed the use of finely pixelled photocathodes obtained from silicon semiconductors. SiPM detectors seem to be an ideal tool for the detection of Cherenkov and fluorescence light in spite of their not yet resolved criticism for operating temperature and intrinsic noise. The main disadvantage of SiPM in this case is the poor sensitivity in the wavelength range 300-400 nm, where the Cherenkov light and fluorescence radiation are generated. We report on the possibility to realize a new kind of pixelled photodetector based on the use of silicon substrate with carbon nanotube compounds, more sensitive to the near UV radiation. Also if at the very beginning, the development of such detector appears very promising and useful for astroparticle physics, both in the ground based arrays and in the space experiments. The detectors are ready to be operated in conditions of measurements without signal amplification.

  13. Nonlinear Vacuum Polarization In Intense Blackbody Radiation And The Generation Of Cherenkov Radiation By Energetic Charged Particles

    Science.gov (United States)

    Wu, Sheldon S. Q.; Hartemann, F. V.; Barty, C. P. J.

    2010-03-01

    A study of thermally-induced vacuum polarization stemming from the Euler-Heisenberg nonlinear radiation correction to Maxwell equations is conducted. While nonlinear effects associated with photon-photon scattering in the photon gas had been previously calculated, we present an analysis in the framework of stochastic electrodynamics. To lowest order of approximation, it is shown that the phase velocity of light is reduced in the presence of intense ambient electromagnetic radiation. Therefore Cherenkov radiation can be generated when charged particles traverse a region of intense blackbody radiation. Suitable conditions may be found in astrophysical environments. Cosmic ray electrons and positrons in the GeV to TeV range meet the energy requirement for this process to occur. We present calculations of the emission characteristics and conditions under which Cherenkov radiation may be observed. This effect combined with synchrotron and inverse Compton processes may lead to a more complete understanding of cosmic ray propagation. Also of interest, the question of the linearity of the relic cosmic microwave background is under investigation using this formalism and will be discussed. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344.

  14. Optical Cherenkov radiation by cascaded nonlinear interaction: an efficient source of few-cycle energetic near- to mid-IR pulses

    DEFF Research Database (Denmark)

    Bache, Morten; Bang, Ole; Zhou, Binbin;

    2011-01-01

    When ultrafast noncritical cascaded second-harmonic generation of energetic femtosecond pulses occur in a bulk lithium niobate crystal optical Cherenkov waves are formed in the near- to mid-IR. Numerical simulations show that the few-cycle solitons radiate Cherenkov (dispersive) waves in the λ = 2...... efficiency is up to 25%. Thus, optical Cherenkov waves formed with cascaded nonlinearities could become an efficient source of energetic near- to mid-IR few-cycle pulses....

  15. Stability Property of Numerical Cherenkov Radiation and its Application to Relativistic Shock Simulations

    CERN Document Server

    Ikeya, Naoki

    2014-01-01

    We studied the stability property of numerical Cherenkov radiation in relativistic plasma flows employing particle-in-cell simulations. Using the implicit finite-difference time-domain method to solve Maxwell equations, we found that nonphysical instability was greatly inhibited with a CFL number of 1.0. The present result contrasts with recently reported results (Vay et al., 2011; Godfrey & Vay,2013) in which magical CFL numbers in the range 0.5-0.7 were obtained with explicit field solvers. In addition, we found employing higher-order shape functions and an optimal implicitness factor further suppressed long-wavelength modes of the instability. The findings allowed the examination of the long-term evolution of a relativistic collisionless shock without the generation of nonphysical wave excitations in the upstream. This achievement will allow us to investigate particle accelerations in relativistic shocks associated with, for example, gamma-ray bursts.

  16. Quantum Cherenkov radiation by spinless and spin-1/2 particles

    CERN Document Server

    Iablokov, Stanislav

    2015-01-01

    In this paper, the Cherenkov radiation process is investigated in the frame of the Quantum Field Theory, both for the spinless and spin-1/2 charged particles. In the latter case, the polarization density matrix technique was used to account for the spin flip. If compared with the Classical Electrodynamics results, in both cases several quantum corrections arise, coinciding up to the photon's energy linear term. It is shown that, while the absolute value of these corrections significantly relies on the refractive index, the relative quantum correction stays independent of the medium in the case of the ultrarelativistic particles. It the case of the spin-1/2 particles it turns out that the spin flip practically never occurs in this process. For both cases, spinless and spin-1/2, the outgoing photon polarization vector lies always in the plane formed by the initial particle's momentum vector and the final photon's wave vector.

  17. Technical memo on PbF2 as a Cherenkov radiator for EM calorimetry

    International Nuclear Information System (INIS)

    It is apparent that the ever increasing rates and radiation levels found in high-energy physics are excluding more and more instrumental techniques. Those techniques that are remaining are often pushed to their theoretical limits. This situation reaches an extreme at the proposed luminosity of the SSC. Also, it is fair to say that at the SSC, after the accelerator itself, calorimetry will be the next most important physics tool. Therefore, we should be ever alert to new calorimetry techniques which may operate in this demanding environment. The material lead fluoride, PbF2, has a real potential of yielding a very compact, high-resolution electromagnetic calorimeter that is both fast and radiation hard. PbF2 is not a scintillator but a Cherenkov radiator like lead glass, but with a radiation length even harder shorter than of BGO. This memo discusses this property as well as comparison PbF2 to other scintillating materials. 2 refs., 14 figs., 1 tab

  18. New peculiarities in angular distribution of Cherenkov radiation from relativistic heavy ions caused by their stopping in radiator: numerical and theoretical research

    Science.gov (United States)

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

    2012-05-01

    A new method and theoretical base for calculation of the Cherenkov Radiation (ChR) angular distribution from relativistic heavy ions (RHI) taking into account stopping in radiator is suggested. Our method is based on the thin radiator approximation and the Bethe-Bloch formula for ionization energy loss (stopping) and provides fast calculations without using any special software. The simple formula for estimation of the ChR angular distribution width in vicinity of the Cherenkov angle taking into account RHI stopping in radiator is obtained. New peculiarities of ChR - dependence on the RHI charge and mass (isotopic effect), emission wavelength (index of refraction) and radiator length - are studied. These new features of ChR from RHI allow for their possible applications to simultaneously reconstruction of both velocity and charge of RHI penetrating through radiator and even to measure the masses of isotopes or radiator stopping power.

  19. Optical Cherenkov radiation by cascaded nonlinear interaction: an efficient source of few-cycle energetic near- to mid-IR pulses

    CERN Document Server

    Bache, M; Zhou, B B; Moses, J; Wise, F W

    2011-01-01

    When ultrafast noncritical cascaded second-harmonic generation of energetic femtosecond pulses occur in a bulk lithium niobate crystal optical Cherenkov waves are formed in the near- to mid-IR. Numerical simulations show that the few-cycle solitons radiate Cherenkov (dispersive) waves in the $\\lambda=2.2-4.5\\mic$ range when pumping at $\\lambda_1=1.2-1.8\\mic$. The exact phase-matching point depends on the soliton wavelength, and we show that a simple longpass filter can separate the Cherenkov waves from the solitons. The Cherenkov waves are born few-cycle with an excellent Gaussian pulse shape, and the conversion efficiency is up to 25%. Thus, optical Cherenkov waves formed with cascaded nonlinearities could become an efficient source of energetic near- to mid-IR few-cycle pulses.

  20. Determination of 90Sr in crude coconut oil by Cherenkov radiation measurement

    International Nuclear Information System (INIS)

    In December 1989, the Analytical Measurements Research group received crude coconut oil samples for radiometric determination of 90Sr as required by the government of an importing country. The limit for 90Sr in imported products was 67 BqKg-1. The possibility of 90Sr contamination of coconut oil is remote, considering that the molecular structures of its constituents do not include inorganic species. However, a method still had to be developed for certifying to the absence of 90Sr in the samples. The technique selected was based on the direct measurement of 90Sr/90Y Cherenkov radiation in oil. For 10 ml of samples (approximately 9 g.) and a counting period of 1 hr. lower limits of detection ranging from 16 to 27 BqKg-1 were obtained. These detection limits, being well below the regulatory limit of 67 BqKg-1 for 90Sr were adequate for purposes of the study. A total of ten crude coconut oil samples analyzed between December 1989 and June 1990 did not have detectable 90Sr/90Y activities. (auth.). 7 refs.; 1 fig

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

    CERN Document Server

    Osmanov, Z

    2015-01-01

    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 (QLD), 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 (ChDI) is quite high, indicating high efficiency of the process. Analyzing 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.

  2. Generation of THz-radiation in the Cherenkov decelerating structure with planar geometry at frequency ∼ 0.675 THz

    Science.gov (United States)

    Ashanin, I. A.; Polozov, S. M.

    2016-07-01

    One of the ways to generate THz-radiation is by the relativistic electron bunches travelling through Cherenkov decelerating dielectric filled capillary channel. Sapphire or other dielectric materials can be used for the internal surface coating of the capillary. Relativistic electron bunches of ∼100 µm in diameter and pulse durations of 1 ps or shorter are capable to produce substantial power of THz-radiation. The aperture of Cherenkov decelerating structure should be comparable with the sub-mm wavelength (0.05-3 mm). Such type of decelerating system allows providing of the wide range of operating parameters at the various geometrical sizes. But it is necessary to consider that such capillaries are difficult in production as there is a requirement to drill a small aperture in a long crystal of high hardness but brittle. In this regard it would be desirable to offer transition option from the axial to the planar geometry. Furthermore the ribbon beam has some advantages as focusing at low energies and possessing smaller expansion in the drift space. The authors present design and results of electrodynamics study of the decelerating planar dielectric filling Cherenkov channel at frequency 0.675 THz in this article. It is also delivered characteristic comparison with axial geometry channel. A horn antenna attached to such channel at 0.675 THz resonant frequency is considered.

  3. Statistical properties of Cherenkov and quasi-Cherenkov superradiance

    CERN Document Server

    Anishchenko, S V

    2016-01-01

    We consider the effects of shot noise and particle energy spread on statistical properties of Cherenkov and quasi-Cherenkov superradiance emitted by a relativistic electron beam. In the absence of energy spread, we have found the root-mean-square deviations of both peak radiated power and instability growth time as a function of the number of particles. It is shown that energy spread can lead to a sharp drop in the radiated power of Cherenkov and quasi-Cherenkov superradiance at high currents.

  4. Cherenkov radiation conversion and collection considerations for a gamma bang time/reaction history diagnostic for the NIF.

    Science.gov (United States)

    Herrmann, Hans W; Mack, Joseph M; Young, Carlton S; Malone, Robert M; Stoeffl, Wolfgang; Horsfield, Colin J

    2008-10-01

    Bang time and reaction history measurements are fundamental components of diagnosing inertial confinement fusion (ICF) implosions and will be essential contributors to diagnosing attempts at ignition on the National Ignition Facility (NIF). Fusion gammas provide a direct measure of fusion interaction rate without being compromised by Doppler spreading. Gamma-based gas Cherenkov detectors that convert fusion gamma rays to optical Cherenkov photons for collection by fast recording systems have been developed and fielded at Omega. These systems have established their usefulness in illuminating ICF physics in several experimental campaigns. Bang time precision better than 25 ps has been demonstrated, well below the 50 ps accuracy requirement defined by the NIF system design requirements. A comprehensive, validated numerical study of candidate systems is providing essential information needed to make a down selection based on optimization of sensitivity, bandwidth, dynamic range, cost, and NIF logistics. This paper presents basic design considerations arising from the two-step conversion process from gamma rays to relativistic electrons to UV/visible Cherenkov radiation.

  5. Monte Carlo simulation of the Cherenkov radiation emitted by TeO{sub 2} crystal when crossed by cosmic muons

    Energy Technology Data Exchange (ETDEWEB)

    Casali, N., E-mail: nicola.casali@gmail.com [Dipartimento di Scienze Fisiche e Chimiche, Università degli studi dell' Aquila, Coppito (AQ) (Italy); Istituto Nazionale di Fisica Nucleare, Laboratori Nazionali del Gran Sasso, Assergi (AQ) (Italy); Bellini, F. [Sapienza Università di roma, P.le A. Moro 2, Roma (Italy); Istituto Nazionale di Fisica Nucleare, Sezione di Roma, P.le A. Moro 2, Roma (Italy); Dafinei, I. [Istituto Nazionale di Fisica Nucleare, Sezione di Roma, P.le A. Moro 2, Roma (Italy); Marafini, M. [Museo Storico della Fisisca e Centro Studi e Ricerche “Enrico Fermi“, Piazza del Viminale 1, Roma (Italy); Morganti, S.; Orio, F.; Pinci, D.; Vignati, M.; Voena, C. [Istituto Nazionale di Fisica Nucleare, Sezione di Roma, P.le A. Moro 2, Roma (Italy)

    2013-12-21

    TeO{sub 2} crystals are currently used as bolometric detectors in experiments searching for the neutrinoless double beta decay of {sup 130}Te. The extreme rarity of the studied signal forces the experiments to reach an ultra low background level. The main background source is represented by α particles emitted by radioactive contaminants placed in the materials that compose and surround the detector. Recent measurements show that a particle discrimination in TeO{sub 2} bolometers detecting the light emitted by β/γ particles is possible, opening the possibility to make large improvements in the performance of experiments based on this kind of materials. In order to understand the nature of this light emission a measurement at room temperature with TeO{sub 2} crystals was performed. According to these results, the detected light was compatible with the Cherenkov emission, even though the scintillation hypothesis could not be discarded. In this work a Monte Carlo (MC) simulation of the Cherenkov radiation emitted by TeO{sub 2} crystal when crossed by cosmic muons was performed. The data from MC and the room temperature measurement are perfectly compatible and prove that the Cherenkov light is the only component of the light yield of TeO{sub 2} crystals.

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

    Science.gov (United States)

    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.

  7. Tunable femtosecond Cherenkov fiber laser

    DEFF Research Database (Denmark)

    Liu, Xiaomin; Svane, Ask Sebastian; Lægsgaard, Jesper;

    2014-01-01

    We demonstrate electrically-tunable femtosecond Cherenkov fiber laser output at the visible range. Using an all-fiber, self-starting femtosecond Yb-doped fiber laser as the pump source and nonlinear photonic crystal fiber link as the wave-conversion medium, ultrafast, milliwatt-level, tunable...... and spectral isolated Cherenkov radiation at visible wavelengths are reported. Such a femtosecond Cherenkov laser source is promising for practical biophotonics applications....

  8. Improvement of optical properties and radiation hardness of NaBi(WO sub 4) sub 2 Cherenkov crystals

    CERN Document Server

    Zadneprovski, B I; Polyansky, E V; Devitsin, E G; Kozlov, V A; Potashov, S Yu; Terkulov, A R

    2002-01-01

    On the basis of the data on melt evaporation while growing NaBi(WO sub 4) sub 2 Cherenkov crystals, the formation of nonstoichiometry and most probable types of dot defects of the crystals have been considered. The influence of melt nonstoichiometry and doping with Sc on optical transmission and radiation hardness of the crystals has been experimentally investigated. The surplus of WO sub 3 has been established to increase optical transmission and radiation hardness and lack of Bi sub 2 O sub 3 in the melt to reduce radiation hardness. Sc doping is shifting the absorption edge to UV region by 30-35 nm and is increasing radiation hardness of the crystals about three-fold. Analytical estimations give the increase of the number of Cherenkov photons by a factor of 1.3, which leads to an improvement of the energy resolution of a calorimeter based on NaBi(WO sub 4) sub 2 :Sc crystals compared with undoped NaBi(WO sub 4) sub 2 of approximately 15%.

  9. Video-rate optical dosimetry and dynamic visualization of IMRT and VMAT treatment plans in water using Cherenkov radiation

    Energy Technology Data Exchange (ETDEWEB)

    Glaser, Adam K., E-mail: Adam.K.Glaser@dartmouth.edu, E-mail: Brian.W.Pogue@dartmouth.edu; Andreozzi, Jacqueline M.; Davis, Scott C. [Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755 (United States); Zhang, Rongxiao [Department of Physics and Astronomy, Dartmouth College, Hanover, New Hampshire 03755 (United States); Pogue, Brian W., E-mail: Adam.K.Glaser@dartmouth.edu, E-mail: Brian.W.Pogue@dartmouth.edu [Department of Physics and Astronomy and Thayer School of Engineering, Dartmouth College, Hanover, New Hampshire 03755 (United States); Fox, Colleen J.; Gladstone, David J. [Norris Cotton Cancer Center, Dartmouth-Hitchcock Medical Center, Lebanon, New Hampshire 03766 (United States)

    2014-06-15

    Purpose: A novel technique for optical dosimetry of dynamic intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) plans was investigated for the first time by capturing images of the induced Cherenkov radiation in water. Methods: A high-sensitivity, intensified CCD camera (ICCD) was configured to acquire a two-dimensional (2D) projection image of the Cherenkov radiation induced by IMRT and VMAT plans, based on the Task Group 119 (TG-119) C-Shape geometry. Plans were generated using the Varian Eclipse treatment planning system (TPS) and delivered using 6 MV x-rays from a Varian TrueBeam Linear Accelerator (Linac) incident on a water tank doped with the fluorophore quinine sulfate. The ICCD acquisition was gated to the Linac target trigger pulse to reduce background light artifacts, read out for a single radiation pulse, and binned to a resolution of 512 × 512 pixels. The resulting videos were analyzed temporally for various regions of interest (ROI) covering the planning target volume (PTV) and organ at risk (OAR), and summed to obtain an overall light intensity distribution, which was compared to the expected dose distribution from the TPS using a gamma-index analysis. Results: The chosen camera settings resulted in 23.5 frames per second dosimetry videos. Temporal intensity plots of the PTV and OAR ROIs confirmed the preferential delivery of dose to the PTV versus the OAR, and the gamma analysis yielded 95.9% and 96.2% agreement between the experimentally captured Cherenkov light distribution and expected TPS dose distribution based upon a 3%/3 mm dose difference and distance-to-agreement criterion for the IMRT and VMAT plans, respectively. Conclusions: The results from this initial study demonstrate the first documented use of Cherenkov radiation for video-rate optical dosimetry of dynamic IMRT and VMAT treatment plans. The proposed modality has several potential advantages over alternative methods including the real

  10. Video-rate optical dosimetry and dynamic visualization of IMRT and VMAT treatment plans in water using Cherenkov radiation

    International Nuclear Information System (INIS)

    Purpose: A novel technique for optical dosimetry of dynamic intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) plans was investigated for the first time by capturing images of the induced Cherenkov radiation in water. Methods: A high-sensitivity, intensified CCD camera (ICCD) was configured to acquire a two-dimensional (2D) projection image of the Cherenkov radiation induced by IMRT and VMAT plans, based on the Task Group 119 (TG-119) C-Shape geometry. Plans were generated using the Varian Eclipse treatment planning system (TPS) and delivered using 6 MV x-rays from a Varian TrueBeam Linear Accelerator (Linac) incident on a water tank doped with the fluorophore quinine sulfate. The ICCD acquisition was gated to the Linac target trigger pulse to reduce background light artifacts, read out for a single radiation pulse, and binned to a resolution of 512 × 512 pixels. The resulting videos were analyzed temporally for various regions of interest (ROI) covering the planning target volume (PTV) and organ at risk (OAR), and summed to obtain an overall light intensity distribution, which was compared to the expected dose distribution from the TPS using a gamma-index analysis. Results: The chosen camera settings resulted in 23.5 frames per second dosimetry videos. Temporal intensity plots of the PTV and OAR ROIs confirmed the preferential delivery of dose to the PTV versus the OAR, and the gamma analysis yielded 95.9% and 96.2% agreement between the experimentally captured Cherenkov light distribution and expected TPS dose distribution based upon a 3%/3 mm dose difference and distance-to-agreement criterion for the IMRT and VMAT plans, respectively. Conclusions: The results from this initial study demonstrate the first documented use of Cherenkov radiation for video-rate optical dosimetry of dynamic IMRT and VMAT treatment plans. The proposed modality has several potential advantages over alternative methods including the real

  11. Analytical Solution for the Stopping Power of the Cherenkov Radiation in a Uniaxial Nanowire Material

    Directory of Open Access Journals (Sweden)

    Tiago A. Morgado

    2015-06-01

    Full Text Available We derive closed analytical formulae for the power emitted by moving charged particles in a uniaxial wire medium by means of an eigenfunction expansion. Our analytical expressions demonstrate that, in the absence of material dispersion, the stopping power of the uniaxial wire medium is proportional to the charge velocity, and that there is no velocity threshold for the Cherenkov emission. It is shown that the eigenfunction expansion formalism can be extended to the case of dispersive lossless media. Furthermore, in the presence of material dispersion, the optimal charge velocity that maximizes the emitted Cherenkov power may be less than the speed of light in a vacuum.

  12. All-fiber generation of 29-fs pulses at 1.3-{\\mu}m via Cherenkov radiation

    CERN Document Server

    Luo, Hao; Wang, Zhiqiang; Zhang, Liang; Feng, Cheng

    2016-01-01

    We have experimentally demonstrated the all-fiber generation of 1.3-{\\mu}m femtosecond pulses via Cherenkov radiation (CR) from an ultrafast Er-doped fiber laser. The experiment shows that the pulses maintain below 40 fs in the range from 1270 to 1315 nm with multi-milliwatt average output power. The shortest generated pulses can be as short as 29 fs. This ultrashort pulse source in 1.3-{\\mu}m window can bring the benefits to many fields such as the bio-imaging and the ultrafast spectroscopy, and so on.

  13. Self-amplified Cherenkov radiation from a relativistic electron in a waveguide partially filled with a laminated material

    CERN Document Server

    Grigoryan, L Sh; Khachatryan, H F; Arzumanyan, S R; Wagner, W

    2012-01-01

    The radiation from a relativistic electron uniformly moving along the axis of cylindrical waveguide filled with laminated material of finite length is investigated. Expressions for the spectral distribution of radiation passing throw the transverse section of waveguide at large distances from the laminated material are derived with no limitations on the amplitude and variation profile of the layered medium permittivity and permeability. Numerical results for layered material consisting of dielectric plates alternated with vacuum gaps are given. It is shown that at a special choice of problem parameters, Cherenkov radiation generated by the relativistic electron inside the plates is self-amplified. The visual explanation of this effect is given and a possible application is discussed.

  14. Cherenkov counter for particle identification test beam

    International Nuclear Information System (INIS)

    The Cherenkov counter used for selecting electrons of the test beam has been studied in this article. The design, manufacture, assembly and testing of the Cherenkov counter are described. And the performance of this counter is measured. The CO2 gas is used as Cherenkov radiator, the XP2020Q photomultiplier is applied for recording signals of the Cherenkov light. The (99.0±0.5)% efficiency of the electron selection has been reached

  15. Development of High Quantum Efficiency UV/Blue Photocathode Epitaxial Semiconductor Heterostructures for Scintillation and Cherenkov Radiation Detection

    Science.gov (United States)

    Leopold, Daniel J.

    2002-01-01

    The primary goal of this research project was to further extend the use of advanced heteroepitaxial-semiconductor crystal growth techniques such as molecular beam epitaxy (MBE) and to demonstrate significant gains in UV/blue photonic detection by designing and fabricating atomically-tailored heteroepitaxial GaAlN/GaInN photocathode device structures. This NASA Explorer technology research program has focused on the development of photocathodes for Cherenkov and scintillation radiation detection. Support from the program allowed us to enhance our MBE system to include a nitrogen plasma source and a magnetic bearing turbomolecular pump for delivery and removal of high purity atomic nitrogen during GaAlN/GaInN film growth. Under this program we have also designed, built and incorporated a cesium activation stage. In addition, a connected UHV chamber with photocathode transfer/positioner components as well as a hybrid phototube stage was designed and built to make in-situ quantum efficiency measurements without ever having to remove the photocathodes from UHV conditions. Thus we have constructed a system with the capability to couple atomically-tailored MBE-grown photocathode heterostructures with real high gain readout devices for single photon detection evaluation.

  16. Experimental Research of the Diffraction and Vavilov-Cherenkov Radiation Generation in a Teflon Target

    CERN Document Server

    Shevelev, M; Potylitsyn, A; Popov, Yu

    2011-01-01

    Geometry of Vavilov-Cherekov (VChR) radiation when an electron moves close to a dielectric target is in analogy to diffraction radiation (DR) geometry. In this case we may expect DR generation from the upstream face of the target besides that VChR. The joint observation of these booth types of radiation is very interesting from the pseudo-photon viewpoint, which is applicable for relativistic electrons. Unexpected results obtained in our experiment insist on reflection about nature both DR and VChR. The experiment was performed on the relativistic electron beam of the microtron of Tomsk Polytechnic University.

  17. Progress in Cherenkov femtosecond fiber lasers

    DEFF Research Database (Denmark)

    Liu, Xiaomin; Svane, Ask Sebastian; Lægsgaard, Jesper;

    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...... 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 supercontinuumbased...

  18. Tachyonic Cherenkov emission from Jupiter's radio electrons

    International Nuclear Information System (INIS)

    Tachyonic Cherenkov radiation from inertial relativistic electrons in the Jovian radiation belts is studied. The tachyonic modes are coupled to a frequency-dependent permeability tensor and admit a negative mass-square, rendering them superluminal and dispersive. The superluminal radiation field can be cast into Maxwellian form, using 3D field strengths and inductions, and the spectral densities of tachyonic Cherenkov radiation are derived. The negative mass-square gives rise to a longitudinal flux component. A spectral fit to Jupiter's radio spectrum, inferred from ground-based observations and the Cassini 2001 fly-by, is performed with tachyonic Cherenkov flux densities averaged over a thermal electron population.

  19. A realistic treatment of geomagnetic Cherenkov radiation from cosmic ray air showers

    NARCIS (Netherlands)

    Werner, Klaus; de Vries, Krijn D.; Scholten, Olaf

    2012-01-01

    We present a macroscopic calculation of coherent electro-magnetic radiation from air showers initiated by ultra-high energy cosmic rays, based on currents obtained from three-dimensional Monte Carlo simulations of air showers in a realistic geo-magnetic field. We discuss the importance of a correct

  20. Particle Identification in Cherenkov Detectors using Convolutional Neural Networks

    CERN Document Server

    Theodore, Tomalty

    2016-01-01

    Cherenkov detectors are used for charged particle identification. When a charged particle moves through a medium faster than light can propagate in that medium, Cherenkov radiation is released in the shape of a cone in the direction of movement. The interior of the Cherenkov detector is instrumented with PMTs to detect this Cherenkov light. Particles, then, can be identified by the shapes of the images on the detector walls.

  1. Poster — Thur Eve — 18: Cherenkov Emission By High-Energy Radiation Therapy Beams: A Characterization Study

    Energy Technology Data Exchange (ETDEWEB)

    Zlateva, Y.; El Naqa, I. [Medical Physics Unit, Department of Oncology, McGill University, Montreal, QC (Canada); Quitoriano, N. [Department of Mining and Materials Engineering McGill University, Montreal, QC (Canada)

    2014-08-15

    We investigate Cherenkov emission (CE) by radiotherapy beams via radiation dose-versus-CE correlation analyses, CE detection optimization by means of a spectral shift towards the near-infrared (NIR) window of biological tissue, and comparison of CE to on-board MV imaging. Dose-CE correlation was investigated via simulation and experiment. A Monte Carlo (MC) CE simulator was designed using Geant4. Experimental phantoms include: water; tissue-simulating phantom composed of water, Intralipid®, and beef blood; plastic phantom with solid water insert. The detector system comprises an optical fiber and diffraction-grating spectrometer incorporating a front/back-illuminated CCD. The NIR shift was carried out with CdSe/ZnS quantum dots (QDs), emitting at (650±10) nm. CE and MV images were acquired with a CMOS camera and electronic portal imaging device. MC and experimental studies indicate a strong linear dose-CE correlation (Pearson coefficient > 0.99). CE by an 18-MeV beam was effectively NIR-shifted in water and a tissue-simulating phantom, exhibiting a significant increase at 650 nm for QD depths up to 10 mm. CE images exhibited relative contrast superior to MV images by a factor of 30. Our work supports the potential for application of CE in radiotherapy online imaging for patient setup and treatment verification, since CE is intrinsic to the beam and non-ionizing and QDs can be used to improve CE detectability, potentially yielding image quality superior to MV imaging for the case of low-density-variability, low-optical-attenuation materials (ex: breast/oropharynx). Ongoing work involves microenvironment functionalization of QDs and application of multi-channel spectrometry for simultaneous acquisition of dosimetric and tumor oxygenation signals.

  2. A Realistic Treatment of Geomagnetic Cherenkov Radiation from Cosmic Ray Air Showers

    OpenAIRE

    Werner, Klaus; de Vries, Krijn D.; Scholten, Olaf

    2012-01-01

    We present a macroscopic calculation of coherent electro-magnetic radiation from air showers initiated by ultra-high energy cosmic rays, based on currents obtained from three-dimensional Monte Carlo simulations of air showers in a realistic geo-magnetic field. We discuss the importance of a correct treatment of the index of refraction in air, given by the law of Gladstone and Dale, which affects the pulses enormously for certain configurations, compared to a simplified treatment using a const...

  3. A GPU-based Calculation Method for Near Field Effects of Cherenkov Radiation Induced by Ultra High Energy Cosmic Neutrinos

    CERN Document Server

    Hu, Chia-Yu; Chen, Pisin

    2010-01-01

    The radio approach for detecting the ultra-high energy cosmic neutrinos has become a mature field. The Cherenkov signals in radio detection are originated from the charge excess of particle showers due to Askaryan effect. The conventional way of calculating the Cherenkov pulses by making Fraunhofer approximation fails when the sizes of the elongated showers become comparable with the detection distances. We present a calculation method of Cherenkov pulses based on the finite-difference time-domain (FDTD) method, and attain a satisfying effeciency via the GPU- acceleration. Our method provides a straightforward way of the near field calculation, which would be important for ultra high energy particle showers, especailly the electromagnetic showers induced by the high energy leptons produced in the neutrino charge current interactions.

  4. Development of a 144-channel Hybrid Avalanche Photo-Detector for Belle II ring-imaging Cherenkov counter with an aerogel radiator

    Energy Technology Data Exchange (ETDEWEB)

    Nishida, S., E-mail: shohei.nishida@kek.jp [High Energy Accelerator Research Organization (KEK), Tsukuba (Japan); Adachi, I. [High Energy Accelerator Research Organization (KEK), Tsukuba (Japan); Hamada, N. [Toho University, Funabashi (Japan); Hara, K. [High Energy Accelerator Research Organization (KEK), Tsukuba (Japan); Iijima, T. [Nagoya University, Nagoya (Japan); Iwata, S.; Kakuno, H. [Tokyo Metropolitan University, Hachioji (Japan); Kawai, H. [Chiba University, Chiba (Japan); Korpar, S.; Krizan, P. [Jozef Stefan Institute, Ljubljana (Slovenia); Ogawa, S. [Toho University, Funabashi (Japan); Pestotnik, R.; Ŝantelj, L.; Seljak, A. [Jozef Stefan Institute, Ljubljana (Slovenia); Sumiyoshi, T. [Tokyo Metropolitan University, Hachioji (Japan); Tabata, M. [Chiba University, Chiba (Japan); Tahirovic, E. [Jozef Stefan Institute, Ljubljana (Slovenia); Yoshida, K. [Tokyo Metropolitan University, Hachioji (Japan); Yusa, Y. [Niigata University, Niigata (Japan)

    2015-07-01

    The Belle II detector, a follow up of the very successful Belle experiment, is under construction at the SuperKEKB electron–positron collider at KEK in Japan. For the PID system in the forward region of the spectrometer, a proximity-focusing ring-imaging Cherenkov counter with an aerogel radiator is being developed. For the position sensitive photon sensor, a 144-channel Hybrid Avalanche Photo-Detector has been developed with Hamamatsu Photonics K.K. In this report, we describe the specification of the Hybrid Avalanche Photo-Detector and the status of the mass production.

  5. Development of a 144-channel Hybrid Avalanche Photo-Detector for Belle II ring-imaging Cherenkov counter with an aerogel radiator

    International Nuclear Information System (INIS)

    The Belle II detector, a follow up of the very successful Belle experiment, is under construction at the SuperKEKB electron–positron collider at KEK in Japan. For the PID system in the forward region of the spectrometer, a proximity-focusing ring-imaging Cherenkov counter with an aerogel radiator is being developed. For the position sensitive photon sensor, a 144-channel Hybrid Avalanche Photo-Detector has been developed with Hamamatsu Photonics K.K. In this report, we describe the specification of the Hybrid Avalanche Photo-Detector and the status of the mass production

  6. TH-C-17A-04: Shining Light On the Implementation of Cherenkov Emission in Radiation Therapy

    Energy Technology Data Exchange (ETDEWEB)

    Zlateva, Y; Quitoriano, N [I El Naqa, McGill University, Montreal, QC (Canada)

    2014-06-15

    Purpose: We hypothesize that Cherenkov emission (CE) by radiotherapy beams is correlated with radiation dose, CE detection can be maximized by a spectral shift towards the near-infrared (NIR) window of biological tissue, and in certain tissue types (ex. breast/oropharynx), it could prove superior to mega-voltage (MV) imaging. Therefore, we compare CE imaging to onboard MV imaging. Methods: Dose-CE correlation was investigated via simulation and experiment. A Monte Carlo (MC) CE simulator was designed using Geant4. Experimental phantoms include: water; tissuesimulating phantom composed of water, fat emulsion, and beef blood; plastic phantom with solid water insert. The optical spectrometry system consisted of a multi-mode optical fiber and diffraction-grating spectrometer incorporating a front/back-illuminated charge-coupled device (CCD). CdSe/ZnS quantum dots (QDs), emitting at (650±10) nm, were used to achieve NIR shift of the CE signal. CE and MV images were acquired with a complementary metal-oxide-semiconductor (CMOS) camera and an electronic portal imaging device (EPID), respectively. Results: MC and experimental studies indicate a strong linear correlation between radiation dose and CE (Pearson coefficient > 0.99). CE by an 18 MeV beam was effectively shifted towards the NIR in water and in a tissue-simulating phantom, exhibiting a 50% increase at 650 nm for QD depths of ∼3 mm. CE images exhibited relative contrast superior to EPID images by a factor of 30. Conclusion: Our work supports the potential for application of CE in radiotherapy online imaging for patient setup and treatment verification, since CE is intrinsic to the beam and non-ionizing, and QDs can be used to improve CE detectability, yielding image quality superior to MV imaging for the case of low density variability, low optical attenuation materials, such as breast or oropharyngeal cavities. Ongoing work involves microenvironment functionalization of QDs and application of multichannel

  7. TH-C-17A-04: Shining Light On the Implementation of Cherenkov Emission in Radiation Therapy

    International Nuclear Information System (INIS)

    Purpose: We hypothesize that Cherenkov emission (CE) by radiotherapy beams is correlated with radiation dose, CE detection can be maximized by a spectral shift towards the near-infrared (NIR) window of biological tissue, and in certain tissue types (ex. breast/oropharynx), it could prove superior to mega-voltage (MV) imaging. Therefore, we compare CE imaging to onboard MV imaging. Methods: Dose-CE correlation was investigated via simulation and experiment. A Monte Carlo (MC) CE simulator was designed using Geant4. Experimental phantoms include: water; tissuesimulating phantom composed of water, fat emulsion, and beef blood; plastic phantom with solid water insert. The optical spectrometry system consisted of a multi-mode optical fiber and diffraction-grating spectrometer incorporating a front/back-illuminated charge-coupled device (CCD). CdSe/ZnS quantum dots (QDs), emitting at (650±10) nm, were used to achieve NIR shift of the CE signal. CE and MV images were acquired with a complementary metal-oxide-semiconductor (CMOS) camera and an electronic portal imaging device (EPID), respectively. Results: MC and experimental studies indicate a strong linear correlation between radiation dose and CE (Pearson coefficient > 0.99). CE by an 18 MeV beam was effectively shifted towards the NIR in water and in a tissue-simulating phantom, exhibiting a 50% increase at 650 nm for QD depths of ∼3 mm. CE images exhibited relative contrast superior to EPID images by a factor of 30. Conclusion: Our work supports the potential for application of CE in radiotherapy online imaging for patient setup and treatment verification, since CE is intrinsic to the beam and non-ionizing, and QDs can be used to improve CE detectability, yielding image quality superior to MV imaging for the case of low density variability, low optical attenuation materials, such as breast or oropharyngeal cavities. Ongoing work involves microenvironment functionalization of QDs and application of multichannel

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

    CERN Document Server

    Knurenko, Stanislav; Petrov, Igor

    2014-01-01

    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.

  9. Determination of location and intensity of radiation through detection of Cherenkov emission in optical fibers. Part 1. method and experimental

    CERN Document Server

    Janata, E

    2002-01-01

    The use of Cherenkov emission in an optical non-scintillating fiber for revealing the position and the intensity of particle showers is described. The experimental set-up and first results are discussed. Results obtained at the TESLA test facility at DESY will be found in the subsequent paper.

  10. TH-C-17A-03: Dynamic Visualization and Dosimetry of IMRT and VMAT Treatment Plans by Video-Rate Imaging of Cherenkov Radiation in Pure Water

    Energy Technology Data Exchange (ETDEWEB)

    Glaser, A; Andreozzi, J; Davis, S [Thayer School of Engineering, Dartmouth College, NH (United States); Zhang, R [Department of Physics and Astronomy, Dartmouth College, Hanover, NH (United States); Fox, C; Gladstone, D [Dartmouth Hitchcock Medical Center, Lebanon, NH (Lebanon); Pogue, B [Thayer School of Engineering, Dartmouth College, NH (United States); Department of Physics and Astronomy, Dartmouth College, Hanover, NH (United States)

    2014-06-15

    Purpose: A novel optical dosimetry technique for the QA and verification of intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) radiotherapy plans was investigated for the first time by capturing images of the induced Cherenkov radiation in water. Methods: An intensified CCD camera (ICCD) was used to acquire a two-dimensional (2D) projection image of the Cherenkov radiation induced by IMRT and VMAT plans, based on the Task Group 119 C-Shape geometry. Plans were generated using the Varian Eclipse treatment planning system (TPS) and delivered using 6 MV x-rays from a Varian TrueBeam Linear Accelerator (Linac) incident on a water tank. The ICCD acquisition was gated to the Linac, operated for single pulse imaging, and binned to a resolution of 512×512 pixels. The resulting videos were analyzed temporally for regions of interest (ROI) covering the planning target volume (PTV) and organ at risk (OAR) and summed to obtain an overall light distribution, which was compared to the expected dose distribution from the TPS using a gammaindex analysis. Results: The chosen camera settings resulted in data at 23.5 frames per second. Temporal intensity plots of the PTV and OAR ROIs confirmed the preferential delivery of dose to the PTV versus the OAR, and the gamma analysis yielded 95.2% and 95.6% agreement between the light distribution and expected TPS dose distribution based upon a 3% / 3 mm dose difference and distance-to-agreement criterion for the IMRT and VMAT plans respectively. Conclusion: The results from this initial study demonstrate the first documented use of Cherenkov radiation for optical dosimetry of dynamic IMRT and VMAT treatment plans. The proposed modality has several potential advantages over alternative methods including the real-time nature of the acquisition, and upon future refinement may prove to be a robust and novel dosimetry method with both research and clinical applications. NIH R01CA109558 and R21EB017559.

  11. TH-C-17A-03: Dynamic Visualization and Dosimetry of IMRT and VMAT Treatment Plans by Video-Rate Imaging of Cherenkov Radiation in Pure Water

    International Nuclear Information System (INIS)

    Purpose: A novel optical dosimetry technique for the QA and verification of intensity-modulated radiation therapy (IMRT) and volumetric-modulated arc therapy (VMAT) radiotherapy plans was investigated for the first time by capturing images of the induced Cherenkov radiation in water. Methods: An intensified CCD camera (ICCD) was used to acquire a two-dimensional (2D) projection image of the Cherenkov radiation induced by IMRT and VMAT plans, based on the Task Group 119 C-Shape geometry. Plans were generated using the Varian Eclipse treatment planning system (TPS) and delivered using 6 MV x-rays from a Varian TrueBeam Linear Accelerator (Linac) incident on a water tank. The ICCD acquisition was gated to the Linac, operated for single pulse imaging, and binned to a resolution of 512×512 pixels. The resulting videos were analyzed temporally for regions of interest (ROI) covering the planning target volume (PTV) and organ at risk (OAR) and summed to obtain an overall light distribution, which was compared to the expected dose distribution from the TPS using a gammaindex analysis. Results: The chosen camera settings resulted in data at 23.5 frames per second. Temporal intensity plots of the PTV and OAR ROIs confirmed the preferential delivery of dose to the PTV versus the OAR, and the gamma analysis yielded 95.2% and 95.6% agreement between the light distribution and expected TPS dose distribution based upon a 3% / 3 mm dose difference and distance-to-agreement criterion for the IMRT and VMAT plans respectively. Conclusion: The results from this initial study demonstrate the first documented use of Cherenkov radiation for optical dosimetry of dynamic IMRT and VMAT treatment plans. The proposed modality has several potential advantages over alternative methods including the real-time nature of the acquisition, and upon future refinement may prove to be a robust and novel dosimetry method with both research and clinical applications. NIH R01CA109558 and R21EB017559

  12. Neutron Detection via the Cherenkov Effect

    Energy Technology Data Exchange (ETDEWEB)

    Bell, Zane W [ORNL; Boatner, Lynn A [ORNL

    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.

  13. Neutron Detection via the Cherenkov Effect

    Energy Technology Data Exchange (ETDEWEB)

    Bell, Zane W [ORNL; Boatner, Lynn A [ORNL

    2008-01-01

    We have incorporated neutron-absorbing elements in transparent, non-scintillating 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 a thermal neutron flux, and give the results of a calculation of the expected response of a detector to a moderated fission spectrum.

  14. Tachyonic Cherenkov emission from Jupiter's radio electrons

    Energy Technology Data Exchange (ETDEWEB)

    Tomaschitz, Roman, E-mail: tom@geminga.org

    2013-12-17

    Tachyonic Cherenkov radiation from inertial relativistic electrons in the Jovian radiation belts is studied. The tachyonic modes are coupled to a frequency-dependent permeability tensor and admit a negative mass-square, rendering them superluminal and dispersive. The superluminal radiation field can be cast into Maxwellian form, using 3D field strengths and inductions, and the spectral densities of tachyonic Cherenkov radiation are derived. The negative mass-square gives rise to a longitudinal flux component. A spectral fit to Jupiter's radio spectrum, inferred from ground-based observations and the Cassini 2001 fly-by, is performed with tachyonic Cherenkov flux densities averaged over a thermal electron population.

  15. The BRAHMS ring imaging Cherenkov detector

    Science.gov (United States)

    Debbe, R.; Jørgensen, C. E.; Olness, J.; Yin, Z.

    2007-01-01

    A Ring Imaging Cherenkov detector built for the BRAHMS experiment at the Brookhaven RHIC is described. This detector has a high index of refraction gas radiator. Cherenkov light is focused on a photo-multiplier based photon detector with a large spherical mirror. The combination of momentum and ring radius measurement provides particle identification from 2.5 to 35 GeV/ c for pions and kaons and well above 40 GeV/ c for protons during runs that had the radiator index of refraction set at n-1=1700×10-6.

  16. All-fiber femtosecond Cherenkov source

    OpenAIRE

    Tu H.; Møller U.; Lægsgaard J.; Liu X.; Boppart S. A.; Turchinovich D.

    2013-01-01

    An all-fiber femtosecond Cherenkov radiation source is demonstrated for the first time, to the best of our knowledge. Using a stable monolithic femtosecond Ybdoped fiber laser as the pump source, and the combination of photonic crystal fibers as the wave-conversion medium, we have generated 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 femtosecond source can find applications in pra...

  17. All-fiber femtosecond Cherenkov source

    Directory of Open Access Journals (Sweden)

    Tu H.

    2013-03-01

    Full Text Available An all-fiber femtosecond Cherenkov radiation source is demonstrated for the first time, to the best of our knowledge. Using a stable monolithic femtosecond Ybdoped fiber laser as the pump source, and the combination of photonic crystal fibers as the wave-conversion medium, we have generated 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 femtosecond source can find applications in practical biophotonics such as bio-imaging and microscopy.

  18. All-fiber femtosecond Cherenkov source

    DEFF Research Database (Denmark)

    Liu, Xiaomin; Lægsgaard, Jesper; Møller, Uffe Visbech;

    2013-01-01

    An all-fiber femtosecond Cherenkov radiation source is demonstrated for the first time, to the best of our knowledge. Using a stable monolithic femtosecond Ybdoped fiber laser as the pump source, and the combination of photonic crystal fibers as the wave-conversion medium, we have generated 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 femtosecond source can find applications in practical biophotonics such as bio-imaging and microscopy....

  19. The Cherenkov Telescope Array

    OpenAIRE

    Bigongiari, Ciro

    2016-01-01

    The Cherenkov Telescope Array (CTA) is planned to be the next generation ground based observatory for very high energy (VHE) gamma-ray astronomy. Gamma-rays provide a powerful insight into the non-thermal universe and hopefully a unique probe for new physics. Imaging Cherenkov telescopes have already discovered more than 170 VHE gamma-ray emitters providing plentiful of valuable data and clearly demonstrating the power of this technique. In spite of the impressive results there are indication...

  20. Study of TOF PET using Cherenkov light

    Science.gov (United States)

    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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Aleissa, Khalid A.; Almasoud, Fahad I.; Islam, Mohammed S. [Atomic Energy Research Institute, King Abdul Aziz City for Science and Technology, P.O. Box 6086, Riyadh 11442 (Saudi Arabia); L' Annunziata, Michael F. [IAEA Expert, Montague Group, P.O. Box 5033, Oceanside, CA 92052-5033 (United States)], E-mail: mlannunziata@cox.net

    2008-12-15

    The activities of {sup 228}Ra in natural waters were determined by the Cherenkov counting of the daughter nuclide {sup 228}Ac. The radium was pre-concentrated on MnO{sub 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 {sup 228}Ra({sup 228}Ac), the daughter nuclide {sup 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 {sup 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 {sup 228}Ac by Cherenkov counting with a very low Cherenkov photon background of 0.317{+-}0.013 cpm. The addition of sodium salicylate into the sample counting vial at a concentration of 0.1 g/mL yielded a more than 3-fold increase in the Cherenkov detection efficiency of {sup 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 {sup 228}Ra and no need for expensive environmentally unfriendly liquid scintillation cocktails. The disadvantages of the Cherenkov counting method include the need to measure {sup 228}Ac Cherenkov photon detection efficiency and optimum Cherenkov counting volume

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

    Science.gov (United States)

    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

  3. The Cherenkov Telescope Array

    CERN Document Server

    Bigongiari, Ciro

    2016-01-01

    The Cherenkov Telescope Array (CTA) is planned to be the next generation ground based observatory for very high energy (VHE) gamma-ray astronomy. Gamma-rays provide a powerful insight into the non-thermal universe and hopefully a unique probe for new physics. Imaging Cherenkov telescopes have already discovered more than 170 VHE gamma-ray emitters providing plentiful of valuable data and clearly demonstrating the power of this technique. In spite of the impressive results there are indications that the known sources represent only the tip of the iceberg. A major step in sensitivity is needed to increase the number of detected sources, observe short time-scale variability and improve morphological studies of extended sources. An extended energy coverage is advisable to observe far-away extragalactic objects and improve spectral analysis. CTA aims to increase the sensitivity by an order of magnitude compared to current facilities, to extend the accessible gamma-ray energies from a few tens of GeV to a hundred o...

  4. Study of Cherenkov Light Lateral Distribution Function around the Knee Region in Extensive Air Showers

    CERN Document Server

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

    2015-01-01

    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 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 which measured with Tunka Cherenkov array experiment. Comparison of the calculated LDF of Cherenkov radiation with that measured at the Tunka EAS array shows the ability for identifying of the primary particle that initiated the EAS cascades determining of its primary energy around the knee region of the cosmic ray spectrum.

  5. The Ring Imaging Cherenkov Detectors for LHCb

    CERN Document Server

    Papanestis, Antonis

    2005-01-01

    The success of the LHCb experiment depends heavily on particle identification over the momentum 2-100 GeV/c. To meet this challenge, LHCb uses a Ring Imaging Cherenkov (RICH) system composed of two detectors with three radiators. RICH1 has both aerogel and gas (C$_4$F$_{10}$) radiators, while RICH2 has only a gas (CF$_4$) radiator. The design of RICH1 is almost complete, whereas RICH2 has been constructed and installed (Nov 2005). Novel Hybrid Photon Detectors (HPDs) have been developed in collaboration with industry to detect the Cherenkov photons. A silicon pixel detector bump-bonded to a readout chip is encapsulated in a vacuum tube. A bi-alkali photocathode is deposited on the inside of the quartz entrance window to convert photons in the range 200-600 nm. The pixel chip is manufactured in 0.25 $\\mu$m deep-submicron radiation-tolerant technology and consists of 1024 logical pixels, each pixel having an area of 0.5 mm x 05. Mm. Photo-electrons are accelerated by a 20kV potential, resulting in a signal of ...

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

    International Nuclear Information System (INIS)

    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 (C2H6 + TMAE), radiator gas (C5F12 + N2) and radiator liquid (C6F14). 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

  7. Cherenkov detector for beam quality measurement

    Science.gov (United States)

    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.

  8. Large acceptance forward Cherenkov detector for the BRAHMS experiment at RHIC

    Science.gov (United States)

    Budick, B.; Beavis, D.; Chasman, C.

    2010-09-01

    A multi-element detector based on Cherenkov radiation in plastic and on photomultiplier tubes has been constructed that is particularly useful in collider experiments. The detector covers the pseudorapidity interval 3.23BRAHMS.

  9. High speed decision electronics combined to a beam Cherenkov counter

    International Nuclear Information System (INIS)

    The Hypolit detector for identification of particles in high energy physics using the Cherenkov radiation, is based on an intensifier tube coupled to photomultipliers via a fiber-optic matrix. Cherenkov photons are focused into a ring; particle identification consists in calculating the ring radius. A fast and high level electronic system is associated to Hypolit. Besides deriving the radius, it allows a background rejection and achieves a momentum correction. This on line tagging contributes to build the WA89 trigger. Tuning is controlled with a micro-computer which makes the access to the heart of the system friendly-user

  10. Light-weight spherical mirrors for Cherenkov detectors

    CERN Document Server

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

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

    DEFF Research Database (Denmark)

    Liu, Xiaomin; Villanueva Ibáñez, Guillermo Eduardo; Lægsgaard, Jesper;

    2013-01-01

    We investigate the noise properties of a femtosecond all-fiber Cherenkov radiation source with emission wavelength around 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, was 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 fiberbased generation at visible wavelengths. Low noise...... makes allfiber Cherenkov sources promising for biophotonics applications such as multi-photon 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....

  12. Silicon photomultiplier based photon detector module as a detector of Cherenkov photons

    Science.gov (United States)

    Korpar, Samo; Chagani, Hassan; Dolenec, Rok; Križan, Peter; Pestotnik, Rok; Stanovnik, Aleš

    2010-11-01

    We have constructed and tested a module, consisting of 64 (= 8×8) Hamamatsu MPPC S10362-11-100P silicon photomultipliers, for position sensitive detection of Cherenkov photons. Suitable light concentrators were produced to increase the efficiency and to improve the signal to noise ratio. The results of our measurements indicate that the performance of such a Cherenkov counter with aerogel radiator could meet the requirements of particle identification at the foreseen upgraded Belle detector.

  13. DELPHI's Ring Imaging Cherenkov Chamber

    CERN Multimedia

    1989-01-01

    The hundreds of mirrors around this Ring Imaging Cherenkov Chamber reflect cones of light created by fast moving particles to a detector. The velocity of a particle can be measured by the size of the ring produced on the detector. DELPHI, which ran from 1989 to 2000 on the LEP accelerator, was primarily concerned with particle identification.

  14. Combined complex Doppler and Cherenkov effect in left-handed metamaterials

    CERN Document Server

    Ziemkiewicz, David

    2015-01-01

    We derive the formula of the complex Doppler shift in a two-dimensional, dispersive metamaterial and we show that a moving, monochromatic radiation source generates multiple frequency modes. The role of the group velocity is stressed and the Doppler shifted radiation field exhibits features of the Cherenkov effect. The presented theory is also applicable to the case of a moving, nonoscillating charge and explains many peculiar characteristics of the Cherenkov radiation in lefthanded metamaterials such as the backward direction of power emission, the constant radiation angle and the lack of velocity threshold.

  15. Test of a ring imaging Cherenkov counter

    International Nuclear Information System (INIS)

    We have tested a ring imaging Cherenkov counter with readout of the projection chamber type. A specific detector response of N0=80 cm-1 was measured which corresponds to 8 photoelectrons per event in a 1.60 m long nitrogen radiator. The resolution of the ring radius was measured to be Δr/r=3.6%. The crosstalk between neighboring wires due to photons generated in the avalanche process was estimated to contribute up to 50% per hit. It was reduced considerably by inserting shielding walls between the wires and by adding C2H6 or iC4H10 to the CH4-TMAE gas mixture. (orig.)

  16. Cherenkov particle identification in FOCUS

    CERN Document Server

    Link, J M; Alimonti, G; Anjos, J C; Arena, V; Bediaga, I; Bianco, S; Boca, G; Bonomi, G; Boschini, M; Butler, J N; Carrillo, S; Casimiro, E; Cawlfield, C; Cheung, H W K; Cho, K; Chung, Y S; Cinquini, L; Cuautle, E; Cumalat, J P; D'Angelo, P; Di Corato, M; Dini, P; Engh, D; Fabbri, Franco Luigi; Gaines, I; Garbincius, P H; Gardner, R; Garren, L A; Giammarchi, M; Gianini, G; Gottschalk, E; Göbel, C; Handler, T; Hernández, H; Hosack, M; Inzani, P; Johns, W E; Kang, J S; Kasper, P H; Kim, D Y; Ko, B R; Kreymer, A E; Kryemadhi, A; Kutschke, R; Kwak, J W; Lee, K B; Leveraro, F; Liguori, G; Magnin, J; Malvezzi, S; Massafferri, A; Menasce, D; Merlo, M M; Mezzadri, M; Milazzo, L; Miranda, J M D; Mitchell, R; Montiel, E; Moroni, L; Méndez, H; Méndez, L; Nehring, M S; O'Reilly, B; Olaya, D; Pantea, D; Paris, A; Park, H; Park, K S; Pedrini, D; Pepe, I M; Pontoglio, C; Prelz, F; Quinones, J; Rahimi, A; Ramírez, J E; Ratti, S P; Reis, A C D; Reyes, M; Riccardi, C; Rivera, C; Rovere, M; Sala, S; Sarwar, S; Segoni, I; Sheaff, M; Sheldon, P D; Stenson, K; Sánchez-Hernández, A; Uribe, C; Vaandering, E W; Vitulo, P; Vázquez, F; Webster, M; Wilson, J R; Wiss, J; Xiong, W; Yager, P M; Zallo, A; Zhang, Y

    2002-01-01

    We describe the algorithm used to identify charged tracks in the fixed-target charm-photoproduction experiment FOCUS. We begin by describing the new algorithm and contrast this approach with that used in our preceding experiment - E687. We next illustrate the algorithm's performance using physics signals. Finally, we briefly describe some of the methods used to monitor the quantum efficiency and noise of the Cherenkov cells.

  17. Cherenkov particle identification in FOCUS

    Energy Technology Data Exchange (ETDEWEB)

    Link, J.M.; Reyes, M.; Yager, P.M.; Anjos, J.C.; Bediaga, I.; Goebel, C.; Magnin, J.; Massafferri, A.; Miranda, J.M. de; Pepe, I.M.; Reis, A.C. dos; Carrillo, S.; Casimiro, E.; Cuautle, E.; Sanchez-Hernandez, A.; Uribe, C.; Vazquez, F.; Cinquini, L.; Cumalat, J.P.; O' Reilly, B.; Ramirez, J.E.; Vaandering, E.W.; Butler, J.N.; Cheung, H.W.K.; Gaines, I.; Garbincius, P.H.; Garren, L.A.; Gottschalk, E.; Kasper, P.H.; Kreymer, A.E.; Kutschke, R.; Bianco, S.; Fabbri, F.L.; Sarwar, S.; Zallo, A.; Cawlfield, C.; Kim, D.Y.; Park, K.S.; Rahimi, A.; Wiss, J. E-mail: jew@uiuc.edu; Gardner, R.; Kryemadhi, A.; Chung, Y.S.; Kang, J.S.; Ko, B.R.; Kwak, J.W.; Lee, K.B.; Park, H.; Alimonti, G.; Boschini, M.; D' Angelo, P.; DiCorato, M.; Dini, P.; Giammarchi, M.; Inzani, P.; Leveraro, F.; Malvezzi, S.; Menasce, D.; Mezzadri, M.; Milazzo, L.; Moroni, L.; Pedrini, D.; Pontoglio, C.; Prelz, F.; Rovere, M.; Sala, S.; Davenport III, T.F.; Agostino, L.; Arena, V.; Boca, G.; Bonomi, G.; Gianini, G.; Liguori, G.; Merlo, M.M.; Pantea, D.; Ratti, S.P.; Riccardi, C.; Segoni, I.; Vitulo, P.; Hernandez, H.; Lopez, A.M.; Mendez, H.; Mendez, L.; Montiel, E.; Olaya, D.; Paris, A.; Quinones, J.; Rivera, C.; Xiong, W.; Zhang, Y.; Wilson, J.R.; Cho, K.; Handler, T.; Mitchell, R.; Engh, D.; Johns, W.E.; Hosack, M.; Nehring, M.S.; Sheldon, P.D.; Stenson, K.; Webster, M.S.; Sheaff, M

    2002-05-21

    We describe the algorithm used to identify charged tracks in the fixed-target charm-photoproduction experiment FOCUS. We begin by describing the new algorithm and contrast this approach with that used in our preceding experiment - E687. We next illustrate the algorithm's performance using physics signals. Finally, we briefly describe some of the methods used to monitor the quantum efficiency and noise of the Cherenkov cells.

  18. Study of a Cherenkov TOF-PET module

    Science.gov (United States)

    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.

  19. Performance test of wavelength-shifting acrylic plastic Cherenkov detector

    CERN Document Server

    Beckford, B; de la Puente, A; Fuji, Y; Futatsukawa, K; Hashimoto, O; Kaneta, M; Kanda, H; Koike, T; Maeda, K; Matsumura, A; Nakamura, S N; Okayasu, Y; Perez, N; Reinhold, J; Shirotori, K; Tamura, H; Tang, L; Tsukada, K

    2010-01-01

    The collection efficiency for Cherenkov light incident on a wavelength shifting plate (WLS) has been determined during a beam test at the Proton Synchrotron facility located in the National Laboratory for High Energy Physics (KEK), Tsukuba, Japan. The experiment was conducted in order to determine the detector's response to photoelectrons converted from photons produced by a fused silica radiator; this allows for an approximation of the detector's quality. The yield of the photoelectrons was measured as a function of the momentum of the incident hadron beam. The yield is proportional to sin2{\\theta}c, where {\\theta}c is the opening angle of the Cherenkov light created. Based on estimations and results from similarly conducted tests, where the collection efficiency was roughly 39%, the experimental result was expected to be around 40% for internally produced light from the WLS. The results of the experiment determined the photon collection response efficiency of the WLS to be roughly 62% for photons created in...

  20. The Ring Imaging Cherenkov detector (RICH) of the AMS experiment

    CERN Document Server

    Barão, F; Alcaraz, J; Arruda, L; Barrau, A; Barreira, G; Belmont, E; Berdugo, J; Brinet, M; Buénerd, M; Casadei, D; Casaus, J; Cortina, E; Delgado, C; Díaz, C; Derome, L; Eraud, L; Garcia-Lopez, R J; Gallin-Martel, L; Giovacchini, F; Gonçalves, P; Lanciotti, E; Laurenti, G; Malinine, A; Maña, C; Marin, J; Martínez, G; Menchaca-Rocha, A; Molla, M; Palomares, C; Panniello, M; Pereira, R; Pimenta, M; Protasov, K; Sánchez, E; Seo, E S; Sevilla, N; Torrento, A; Vargas-Trevino, M; Veziant, O

    2006-01-01

    The Alpha Magnetic Spectrometer (AMS) experiment to be installed on the International Space Station (ISS) will be equipped with a proximity focusing Ring Imaging Cherenkov (RICH) detector for measuring the electric charge and velocity of the charged cosmic particles. A RICH prototype consisting of 96 photomultiplier units, including a piece of the conical reflector, was built and its performance evaluated with ion beam data. Preliminary results of the in-beam tests performed with ion fragments resulting from collisions of a 158 GeV/c/nuc primary beam of Indium ions (CERN SPS) on a Pb target are reported. The collected data included tests to the final front-end electronics and to different aerogel radiators. Cherenkov rings for a large range of charged nuclei and with reflected photons were observed. The data analysis confirms the design goals. Charge separation up to Fe and velocity resolution of the order of 0.1% for singly charged particles are obtained.

  1. The Ring Imaging CHerenkov Detectors of the LHCb Experiment

    CERN Document Server

    Perego, Davide Luigi

    2012-01-01

    Particle identification is a fundamental requirement of the LHCb experiment to fulfill its physics programme. Positive hadron identification is performed by two Ring Imaging CHerenkov (RICH) detectors. This system covers the full angular acceptance of the experiment and is equipped with three Cherenkov radiators to identify particles in a wide momentum range from1 GeV/ c up to 100 GeV/ c . The Hybrid Photon Detectors (HPDs) located outside the detector acceptance provide the photon detection with 500,000 channels. Specific read–out electronics has been developed to readout and process data from the HPDs including data transmission and power distribution. The operation and performanceoftheRICHsystemare ensuredbythe constant controland monitoringoflowandhighvoltage systems,of thegas qualityandenvironmental parameters,ofthe mirror alignment,and finallyofthe detector safety. The description of the LHCb RICH is given. The experience in operating the detector at the Large Hadron Collider is presented and discusse...

  2. The upgraded MAGIC Cherenkov telescopes

    Energy Technology Data Exchange (ETDEWEB)

    Tescaro, D., E-mail: dtescaro@iac.es [Instituto de Astrofísica de Canarias (IAC), E-38205 La Laguna, Tenerife (Spain); Universidad de La Laguna (ULL), Dept. Astrofísica, E-38206 La Laguna, Tenerife (Spain)

    2014-12-01

    The MAGIC Cherenkov telescopes underwent a major upgrade in 2011 and 2012. A new 1039-pixel camera and a larger area digital trigger system were installed in MAGIC-I, making it essentially identical to the newer MAGIC-II telescope. The readout systems of both telescopes were also upgraded, with fully programmable receiver boards and DRS4-chip-based digitization systems. The upgrade eased the operation and maintenance of the telescopes and also improved significantly their performance. The system has now an integral sensitivity as good as 0.6% of the Crab Nebula flux (for E>400GeV), with an effective analysis threshold at 70 GeV. This allows MAGIC to secure one of the leading roles among the current major ground-based Imaging Atmospheric Cherenkov telescopes for the next 5–10 years. - Highlights: • In 2011 and 2012 the MAGIC telescopes underwent a two-stage major upgrade. • The new camera of MAGIC-I allows us to exploit a 1.4 larger trigger area. • The novel DRS4-based readout systems allow a cost-effective ultra-fast digitization. • The upgrade greatly improved the maintainability of the system. • MAGIC has now an optimal integral sensitivity of 0.6% of the Crab Nebula flux.

  3. INTENSITY INTERFEROMETRY WITH CHERENKOV TELESCOPES

    Directory of Open Access Journals (Sweden)

    D. B. Kieda

    2010-01-01

    Full Text Available Se discuten las capacidades de arreglos de interferometría de intensidad estelar (SII que se pueden construir usando la siguiente generación de arreglos de telescopios de Cherenkov de imágenes de aire (IACTs. Estos arreglos de IACT tendrán un gran diámetro de - 100 m (> 8 m de re ectores ópticos, ofreciendo cerca de 5000 líneas de base interferométricas, extendiéndose a partir de 50 m a más que 1000 m. La implementación del SII en arreglos de IACT permitirán imágenes de alta resolución (< 0:1 mas en anchos de banda cortos (bandas B/V, que son óptimas para el estudio de estrellas calientes.

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, R; Pogue, B [Dartmouth College, Hanover, NH (United States); Glaser, A; Gladstone, D [Dartmouth Hitchcock-Medical Center, Hanover, NH (United States)

    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

  5. Nonlinear Cherenkov difference-frequency generation exploiting birefringence of KTP

    International Nuclear Information System (INIS)

    In this letter, we demonstrate the realization of nonlinear Cherenkov difference-frequency generation (CDFG) exploiting the birefringence property of KTiOPO4 (KTP) crystal. The pump and signal waves were set to be along different polarizations, thus the phase-matching requirement of CDFG, which is, the refractive index of the pump wave should be smaller than that of the signal wave, was fulfilled. The radiation angles and the intensity dependence of the CDFG on the pump wave were measured, which agreed well with the theoretical ones

  6. NICHE: The Non-Imaging CHErenkov Array

    CERN Document Server

    Bergman, Douglas

    2012-01-01

    The accurate measurement of the Cosmic Ray (CR) nuclear composition around and above the Knee (~ 10^15.5 eV) has been difficult due to uncertainties inherent to the measurement techniques and/or dependence on hadronic Monte Carlo simulation models required to interpret the data. Measurement of the Cherenkov air shower signal, calibrated with air fluorescence measurements, offers a methodology to provide an accurate measurement of the nuclear composition evolution over a large energy range. NICHE will use an array of widely-spaced, non-imaging Cherenkov counters to measure the amplitude and time-spread of the air shower Cherenkov signal to extract CR nuclear composition measurements and to cross-calibrate the Cherenkov energy and composition measurements with TA/TALE fluorescence and surface detector measurements.

  7. Features and performance of a large gas Cherenkov detector with threshold regulation

    Energy Technology Data Exchange (ETDEWEB)

    Alberdi, J.; Alvarez-Taviel, J.; Asenjo, L.; Colino, N.; Diez-Hedo. F.; Duran, I.; Gonzalez, J.; Hernandez, J.J.; Ladron de Guevara, P.; Marquina, M.A.

    1988-01-15

    We present here the development, main features and calibration procedures for a new type of gas Cherenkov detector, based upon the ability to control its threshold by regulating the temperature of the gas used as radiator. We also include the performance of this detector in particle identification.

  8. Measurement of Cherenkov photons by SiPMs with light guides

    Energy Technology Data Exchange (ETDEWEB)

    Korpar, S. [Faculty of Chemistry and Chemical Engineering, University of Maribor (Slovenia); J. Stefan Institute, Ljubljana (Slovenia)], E-mail: samo.korpar@ijs.si; Chagani, H.; Dolenec, R. [J. Stefan Institute, Ljubljana (Slovenia); Hara, K.; Iijima, T. [Nagoya University, Nagoya (Japan); Krizan, P. [J. Stefan Institute, Ljubljana (Slovenia); Faculty of Mathematics and Physics, University of Ljubljana (Slovenia); Mazuka, Y. [Nagoya University, Nagoya (Japan); Pestotnik, R. [J. Stefan Institute, Ljubljana (Slovenia); Stanovnik, A. [J. Stefan Institute, Ljubljana (Slovenia); Faculty of Electrical Engineering, University of Ljubljana (Slovenia); Yamaoka, M. [Nagoya University, Nagoya (Japan)

    2009-10-21

    Silicon Photomultipliers (SiPMs) are attractive photon detectors for Ring Imaging Cherenkov (RICH) counters inside large magnetic spectrometers due to their insensitivity to magnetic fields. We have investigated the possibilities offered by these new photon detectors in a cosmic ray test set-up. Cherenkov photons emitted by cosmic ray particles in an aerogel radiator have been detected with silicon photomultipliers for the first time. Estimates and tests show how light concentrators may improve the detection efficiency, thus showing promise for a SiPM based RICH detector. The optimum shape for these light guides is investigated.

  9. Cherenkov light detection as a velocity selector for uranium fission products at intermediate energies

    Science.gov (United States)

    Yamaguchi, T.; Enomoto, A.; Kouno, J.; Yamaki, S.; Matsunaga, S.; Suzaki, F.; Suzuki, T.; Abe, Y.; Nagae, D.; Okada, S.; Ozawa, A.; Saito, Y.; Sawahata, K.; Kitagawa, A.; Sato, S.

    2014-12-01

    The in-flight particle separation capability of intermediate-energy radioactive ion (RI) beams produced at a fragment separator can be improved with the Cherenkov light detection technique. The cone angle of Cherenkov light emission varies as a function of beam velocity. This can be exploited as a velocity selector for secondary beams. Using heavy ion beams available at the HIMAC synchrotron facility, the Cherenkov light angular distribution was measured for several thin radiators with high refractive indices (n = 1.9 ~ 2.1). A velocity resolution of ~10-3 was achieved for a 56Fe beam with an energy of 500 MeV/nucleon. Combined with the conventional rigidity selection technique coupled with energy-loss analysis, the present method will enable the efficient selection of an exotic species from huge amounts of various nuclides, such as uranium fission products at the BigRIPS fragment separator located at the RI Beam Factory.

  10. Prototype Test Results of the Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE)

    CERN Document Server

    Williams, D A; Manna, D S; Marion, G M; Ong, R A; Tunner, T O; Dragovan, M; Oser, S; Chantel, M C; Bhattacharya, D P; Covault, C E; Fernholx, R

    1998-01-01

    There are currently no experiments, either satellite or ground-based, that are sensitive to astrophysical gamma-rays at energies between 20 and 250 GeV. We are developing the Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) to explore this energy range. STACEE will use heliostat mirrors at a solar research facility to collect Cherenkov light from extensive air showers produced by high energy gamma-rays. Here we report on the results of prototype test work at the solar facility of Sandia National Laboratories (Albuquerque, NM). The work demonstrates that the facility is suitable for use as an astrophysical observatory. In addition, using a full scale prototype of part of STACEE, we detected atmospheric Cherenkov radiation at energies lower than any other ground-based experiment to date.

  11. Synchrotron emission driven by the Cherenkov-drift instability in active galactic nuclei

    CERN Document Server

    Osmanov, Zaza

    2012-01-01

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

  12. Influence of aerosols from biomass burning on the spectral analysis of Cherenkov telescopes

    CERN Document Server

    Reyes, R de los; Bernloehr, K; Krueger, P; Deil, C; Gast, H; Kosack, K; Marandon, V

    2013-01-01

    During the last decade, imaging atmospheric Cherenkov telescopes (IACTs) have proven themselves as astronomical detectors in the very-high-energy (VHE; E>0.1 TeV) regime. The IACT technique observes the VHE photons indirectly, using the Earth's atmosphere as a calorimeter. Much of the calibration of Cherenkov telescope experiments is done using Monte Carlo simulations of the air shower development, Cherenkov radiation and detector, assuming certain models for the atmospheric conditions. Any deviation of the real conditions during observations from the assumed atmospheric model will result in a wrong reconstruction of the primary gamma-ray energy and the resulting source spectra. During eight years of observations, the High Energy Stereoscopic System (H.E.S.S.) has experienced periodic natural as well as anthropogenic variations of the atmospheric transparency due to aerosols created by biomass burning. In order to identify data that have been taken under such long-term reductions in atmospheric transparency, ...

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

    Science.gov (United States)

    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.

  14. Characterization study of silica aerogel for Cherenkov imaging

    Energy Technology Data Exchange (ETDEWEB)

    Sallaz-Damaz, Y. [LPSC, IN2P3/CNRS, 53 av. des Martyrs, 38026 Grenoble Cedex (France); Derome, L., E-mail: derome@lpsc.in2p3.f [LPSC, IN2P3/CNRS, 53 av. des Martyrs, 38026 Grenoble Cedex (France); Mangin-Brinet, M.; Loth, M.; Protasov, K.; Putze, A.; Vargas-Trevino, M.; Veziant, O.; Buenerd, M. [LPSC, IN2P3/CNRS, 53 av. des Martyrs, 38026 Grenoble Cedex (France); Menchaca-Rocha, A.; Belmont, E.; Vargas-Magana, M.; Leon-Vargas, H.; Ortiz-Velasquez, A. [Instituto de Fisica, UNAM, AP 20-364, Mexico DF (Mexico); Malinine, A. [University of Maryland, College Park, MD 20742 (United States); Barao, F.; Pereira, R. [LIP, Avenida Elias Garcia 14-1, P - 1000 Lisboa (Portugal); Bellunato, T.; Matteuzzi, C.; Perego, D.L. [Universita degli Studi di Milano-Bicocca and INFN, Milano (Italy)

    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 DELTAnapprox1.5x10{sup -4} and DELTAnapprox5x10{sup -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 and 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{sup -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.

  15. Measurements and elimination of Cherenkov light in fiber-optic scintillating detector for electron beam therapy dosimetry

    International Nuclear Information System (INIS)

    In this study, a miniature fiber-optic radiation detector has been developed using a water-equivalent organic scintillator for electron beam therapy dosimetry. Usually, two kinds of light signals such as fluorescent and Cherenkov lights are generated in a fiber-optic radiation detector when a high-energy electron beam is irradiated. The fluorescent light signal is produced in the scintillator and is transmitted through a plastic optical fiber to a remote light-measuring device such as a PMT or a photodiode. The Cherenkov light could be also produced in the plastic optical fiber itself and be detected by a light-measuring device. Therefore, it could cause problems or limit the accuracy of the detection of a fluorescent light signal that is proportional to dose. The objectives of this study are to measure, characterize and eliminate Cherenkov light generated in a plastic optical fiber used as a component of a fiber-optic radiation detector and to detect a real fluorescent light signal from the scintillator. In this study, the intensity of Cherenkov light is measured and characterized as a function of the incident angle of an electron beam from a LINAC, as a function of the electron beam energy, and as a function of electron beam size. Also, a subtraction method using a background optical fiber without a scintillator and an optical discrimination method using optical filters are investigated to remove Cherenkov light

  16. Volcanoes muon imaging using Cherenkov telescopes

    CERN Document Server

    Catalano, Osvaldo; Mineo, Teresa; Cusumano, Giancarlo; Maccarone, Maria Concetta; Pareschi, Giovanni

    2015-01-01

    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 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 energ...

  17. Sites in Argentina for the Cherenkov Telescope Array Project

    CERN Document Server

    Allekotte, Ingo; Etchegoyen, Alberto; García, Beatriz; Mancilla, Alexis; Maya, Javier; Ravignani, Diego; Rovero, Adrián

    2013-01-01

    The Cherenkov Telescope Array (CTA) Project will consist of two arrays of atmospheric Cherenkov telescopes to study high-energy gamma radiation in the range of a few tens of GeV to beyond 100 TeV. To achieve full-sky coverage, the construction of one array in each terrestrial hemisphere is considered. Suitable candidate sites are being explored and characterized. The candidate sites in the Southern Hemisphere include two locations in Argentina, one in San Antonio de los Cobres (Salta Province, Lat. 24:02:42 S, Long. 66:14:06 W, at 3600 m.a.s.l) and another one in El Leoncito (San Juan Province, Lat. 31:41:49 S, Long. 69:16:21 W, at 2600 m.a.s.l). Here we describe the two sites and the instrumentation that has been deployed to characterize them. We summarize the geographic, atmospheric and climatic data that have been collected for both of them.

  18. 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)

    Science.gov (United States)

    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

  19. Possibility of Using a Satellite-Based Detector for Recording Cherenkov Light from Ultrahigh-Energy Extensive Air Showers Penetrating into the Ocean Water

    CERN Document Server

    Shustova, O P; Khrenov, B A

    2011-01-01

    We have estimated the reflected component of Cherenkov radiation, which arises in developing of an extensive air shower with primary energy of 10^20 eV over the ocean surface. It has been shown that, under conditions of the TUS experiment, a flash of the reflected Cherenkov photons at the end of the fluorescence track can be identified in showers with zenith angles up to 20 degrees.

  20. The PHENIX ring imaging Cherenkov detector

    Energy Technology Data Exchange (ETDEWEB)

    Akiba, Y.; Begay, R.; Burwood-Hoy, J.; Chappell, R.B.; Crook, D.W.; Ebisu, K.; Emery, M.S.; Ferrierra, J.; Frawley, A.D.; Hamagaki, H.; Hara, H.; Hayano, R.S.; Hemmick, T.K.; Hibino, M.; Hutter, R.; Kennedy, M.; Kikuchi, J.; Matsumoto, T.; Moscone, G.G.; Nagasaka, Y.; Nishimura, S.; Oyama, K.; Sakaguchi, T.; Salomone, S.; Shigaki, K.; Tanaka, Y.; Walker, J.W.; Wintenberg, A.L.; Young, G.R

    2000-10-11

    The PHENIX experiment at RHIC is primarily a lepton and photon detector. Electron detection takes place in the two central arms of PHENIX, with the primary electron identifier in each arm being a ring imaging Cherenkov detector. This paper contains a description of the two identical RICH detectors and of their expected performance.

  1. Progress on Cherenkov Reconstruction in MICE

    CERN Document Server

    Kaplan, Daniel M; Rajaram, Durga; Winter, Miles; Cremaldi, Lucien; Sanders, David; Summers, Don

    2016-01-01

    Two beamline Cherenkov detectors (Ckov-a,-b) support particle identification in the MICE beamline. Electrons and high-momentum muons and pions can be identified with good efficiency. We report on the Ckov-a,-b performance in detecting pions and muons with MICE Step I data and derive an upper limit on the pion contamination in the standard MICE muon beam.

  2. Fundamental and exotic physics with Cherenkov telescopes

    Energy Technology Data Exchange (ETDEWEB)

    De Angelis, A., E-mail: alessandro.de.angelis@cern.c [Dipartimento di Fisica dell' Universita di Udine and INFN, Udine (Italy); De Lotto, B. [Dipartimento di Fisica dell' Universita di Udine and INFN, Udine (Italy); Roncadelli, M. [INFN Pavia (Italy)

    2011-02-21

    The detection of high-energy {gamma} rays from astrophysical sources, using the Fermi/LAT detector and in the very-high-energy limit the Cherenkov telescopes MAGIC, H.E.S.S. and VERITAS, can provide tests of fundamental physics with unprecedented sensitivity, and possibly allows to probe new and exotic scenarios.

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

    International Nuclear Information System (INIS)

    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

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

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, R; Glaser, A [Dartmouth College, Hanover, NH - New Hampshire (United States); Jarvis, L [Dartmouth-Hitchcock Medical Center, City Of Lebanon, New Hampshire (United States); Gladstone, D [Dartmouth-Hitchcock Medical Center, Hanover, City of Lebanon (Lebanon); Andreozzi, J; Hitchcock, W; Pogue, B [Dartmouth College, Hanover, NH (United States)

    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

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

    International Nuclear Information System (INIS)

    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 ultraviolet 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 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

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

    Science.gov (United States)

    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.

  8. Design and construction of a Cherenkov imager for charge measurement of nuclear cosmic rays

    CERN Document Server

    Bourrion, O; Bondoux, D; Bouly, J L; Bouvier, J; Boyer, B; Brinet, M; Buenerd, M; Damieux, G; Derome, L; Eraud, L; Foglio, R; Fombaron, D; Grondin, D; Lee, M H; Lutz, L; Marton, M; Menchaca-Rocha, A; Pelissier, A; Périé, J N; Putze, A; Roudier, S; Sallaz-Damaz, Y; Seo, E S; Scordilis, J P; Yoon, Y S

    2011-01-01

    A proximity focusing Cherenkov imager called CHERCAM, has been built for the charge measurement of nuclear cosmic rays with the CREAM instrument. It consists of a silica aerogel radiator plane across from a detector plane equipped with 1,600 1" diameter photomultipliers. The two planes are separated by a ring expansion gap. The Cherenkov light yield is proportional to the charge squared of the incident particle. The expected relative light collection accuracy is in the few percents range. It leads to an expected single element separation over the range of nuclear charge Z of main interest 1 < Z < 26. CHERCAM is designed to fly with the CREAM balloon experiment. The design of the instrument and the implemented technical solutions allowing its safe operation in high altitude conditions (radiations, low pressure, cold) are presented.

  9. Design and construction of a Cherenkov imager for charge measurement of nuclear cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Bourrion, O; Bernard, C; Bondoux, D; Bouly, J L; Bouvier, J; Boyer, B; Brinet, M; Buenerd, M; Damieux, G; Derome, L; Eraud, L; Foglio, R; Fombaron, D; Grondin, D; Marton, M; Pelissier, A [Laboratoire de Physique Subatomique et de Cosmologie, Universite Joseph Fourier Grenoble 1, CNRS/IN2P3, Institut Polytechnique de Grenoble, 53, rue des Martyrs, Grenoble (France); Lee, M H; Lutz, L [University of Maryland, College Park MD 20742 (United States); Menchaca-Rocha, A [Instituto de Fisica, UNAM, A.P. 20-364, 01000 Mexico DF (Mexico); Perie, J N, E-mail: olivier.bourrion@lpsc.in2p3.fr [Universite de Toulouse, INSA, UPS, Mines Albi, ISAE, ICA (Institut Clement Ader), 133, avenue de Rangueil, F-31077 Toulouse (France)

    2011-06-15

    A proximity focusing Cherenkov imager called CHERCAM, has been built for the charge measurement of nuclear cosmic rays with the CREAM instrument. It consists of a silica aerogel radiator plane across from a detector plane equipped with 1,600 1'' diameter photomultipliers. The two planes are separated by a ring expansion gap. The Cherenkov light yield is proportional to the charge squared of the incident particle. The expected relative light collection accuracy is in the few percents range. It leads to an expected single element separation over the range of nuclear charge Z of main interest 1 {<=} Z{approx}<26. CHERCAM is designed to fly with the CREAM balloon experiment. The design of the instrument and the implemented technical solutions allowing its safe operation in high altitude conditions (radiations, low pressure, cold) are presented.

  10. Evidence for Observation of Virtual Radio Cherenkov Fields

    CERN Document Server

    Bean, Alice; Snow, James

    2010-01-01

    We present evidence for observation of virtual electromagnetic fields in the radio domain from experiment T926 at the Fermilab Meson Test Beam Facility. Relativistic protons with 120 GeV energy traversed a sealed electromagnetic cavity and were observed in the radio regime of 200MHz-GHz. Closely related to ordinary Cherenkov radiation, which we also measured, the virtual fields require no acceleration for their existence. The experiment is also the first observation of fields from hadronic showers, an independent and new confirmation of coherent radio emission from ultra-relativistic particles. Conditions of very low signal to noise were overcome by a novel and unbiased filtering strategy that exploits exhaustive studies of correlations in the noise backgrounds. Linear scaling of the signal region with the number of beam particles provides evidence of coherence. Extrapolation to measurement of the field of a single relativistic proton charge is consistent within errors. Our study also illustrates new data pro...

  11. Silicon photomultiplier as a detector of Cherenkov photons

    Science.gov (United States)

    Korpar, S.; Dolenec, R.; Hara, K.; Iijima, T.; Križan, P.; Mazuka, Y.; Pestotnik, R.; Stanovnik, A.; Yamaoka, M.

    2008-09-01

    A novel photon detector—i.e. the silicon photomultiplier—whose main advantage over conventional photomultiplier tubes is the operation in high magnetic fields, has been tested as a photon detector in a proximity focusing RICH with aerogel radiator. This type of RICH counter is proposed for the upgrade of the Belle detector at the KEK B-factory. Recently produced silicon photomultipliers show less noise and have larger size, which are important issues for a large area photon detector. We measured the single photon pulse height distribution, the timing resolution and the position sensitivity for different silicon photomultipliers (Hamamatsu MPPC HC025, HC050, and HC100). The silicon photomultipliers were then used to detect Cherenkov photons emitted by cosmic ray particles in a proximity focusing aerogel RICH. Various light guides were investigated in order to increase the detection efficiency.

  12. Experimental set-up of the LUNASKA lunar Cherenkov observations at the ATCA

    OpenAIRE

    James, C.W.; Ekers, R. D.; Philips, C. J.; Protheroe, R.J.; Roberts, P.; Robinson, R A; Alvarez-Muñiz, J.; Bray, J. D.

    2009-01-01

    This contribution describes the experimental set-up implemented by the LUNASKA project at the Australia Telescope Compact Array (ATCA) to enable the radio-telescope to be used to search for pulses of coherent Cherenkov radiation from UHE particle interactions in the Moon with an unprecedented bandwidth, and hence sensitivity. Our specialised hardware included analogue de-dispersion filters to coherently correct for the dispersion expected of a ~nanosecond pulse in the Earth's ionosphere over ...

  13. Characterization study of silica aerogel for Cherenkov imaging

    International Nuclear Information System (INIS)

    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∼1.5x10-4 and Δn∼5x10-4 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 and 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.

  14. Characterization study of silica aerogel for Cherenkov imaging

    Science.gov (United States)

    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.

  15. Performance study of wavelength shifting acrylic plastic for Cherenkov light detection

    Energy Technology Data Exchange (ETDEWEB)

    Beckford, B., E-mail: beckford@aps.org [American Physical Society, One Physics Ellipse, College Park, MD 20740 (United States); De la Puente, A. [TRIUMF Laboratory, 4004 Wesbrook Mall, Vancouver, BC, Canada V6T 2A3 (Canada); Fujii, Y.; Hashimoto, O.; Kaneta, M.; Kanda, H.; Maeda, K.; Matsumura, A.; Nakamura, S.N. [Department of Physics, Tohoku University, Sendai 980-8578 (Japan); Perez, N.; Reinhold, J. [Department of Physics, Florida International University, Miami, FL 33199 (United States); Tang, L. [Department of Physics, Hampton University, Hampton, VA 23668 (United States); Tsukada, K. [Department of Physics, Tohoku University, Sendai 980-8578 (Japan)

    2014-01-21

    The collection efficiency for Cherenkov light incident on a wavelength shifting plate (WLS) has been determined during a beam test at the Proton Synchrotron facility located in the National Laboratory for High Energy Physics (KEK), Tsukuba, Japan. The experiment was conducted in order to determine the detector's response to photoelectrons converted from photons produced by a fused silica radiator; this allows for an approximation of the detector's quality. The yield of the photoelectrons produced through internally generated Cherenkov light as well as light incident from the radiator was measured as a function of the momentum of the incident hadron beam. The yield is proportional to sin{sup 2}θ{sub c}, where θ{sub c} is the opening angle of the Cherenkov light created. Based on estimations and results from similar conducted tests, where the collection efficiency was roughly 39%, the experimental result was expected to be around 40% for internally produced light from the WLS. The results of the experiment determined the photon collection response efficiency of the WLS to be roughly 62% for photons created in a fused silica radiator and 41% for light created in the WLS.

  16. Wavelength Shifters for Water Cherenkov Detectors

    CERN Document Server

    Dai, Xiongxin; Bellerive, Alain; Hargrove, Cliff; Sinclair, David; Mifflin, Cathy; Zhang Feng

    2008-01-01

    The light yield of a water-based Cherenkov detector can be significantly improved by adding a wavelength shifter. Wavelength shifter (WLS) molecules absorb ultraviolet photons and re-emit them at longer wavelengths where typical photomultiplier tubes are more sensitive. In this study, several wavelength shifter compounds are tested for possible deployment in the Sudbury Neutrino Observatory (SNO). Test results on optical properties and chemical compatibility for a few WLS candidates are reported; together with timing and gain measurements. A Monte Carlo simulation of the SNO detector response is used to estimate the total light gain with WLS. Finally, a cosmic ray Cherenkov detector was built to investigate the optical properties of WLS.

  17. Mirror Development for the Cherenkov Telescope Array

    CERN Document Server

    Förster, A; Baba, H; Bähr, J; Bonardi, A; Bonnoli, G; Brun, P; Canestrari, R; Chadwick, P; Chikawa, M; Carton, P -H; De Souza, V; Dipold, J; Doro, M; Durand, D; Dyrda, M; Giro, E; Glicenstein, J -F; Hanabata, Y; Hayashida, M; Hrabovski, M; Jeanney, C; Kagaya, M; Katagiri, H; Lessio, L; MANDAT, D; Mariotti, M; Medina, C; Michałowski, J; Micolon, P; Nakajima, D; Niemiec, J; Nozato, A; Palatka, M; Pareschi, G; Pech, M; Peyaud, B; Pühlhofer, G; Rataj, M; Rodeghiero, G; Rojas, G; Rousselle, J; Sakonaka, R; Schovanek, P; Seweryn, K; Schultz, C; Shu, S; Stinzing, F; Stodulski, M; Teshima, M; Travniczek, P; Van Eldik, C; Vassiliev, V; Wiśniewski, Ł; Wörnlein, A; Yoshida, T

    2013-01-01

    The Cherenkov Telescope Array (CTA) is a planned observatory for very-high energy gamma-ray astronomy. It will consist of several tens of telescopes of different sizes, with a total mirror area of up to 10,000 square meters. Most mirrors of current installations are either polished glass mirrors or diamond-turned aluminium mirrors, both labour intensive technologies. For CTA, several new technologies for a fast and cost-efficient production of light-weight and reliable mirror substrates have been developed and industrial pre-production has started for most of them. In addition, new or improved aluminium-based and dielectric surface coatings have been developed to increase the reflectance over the lifetime of the mirrors compared to those of current Cherenkov telescope instruments.

  18. Bokeh Mirror Alignment for Cherenkov Telescopes

    CERN Document Server

    Ahnen, M L; 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

    2016-01-01

    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 alignment 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 ...

  19. Performance of the STACEE Atmospheric Cherenkov Telescope

    CERN Document Server

    Williams, D A; Boone, L M; Chantell, M C; Conner, Z; Covault, C E; Dragovan, M; Fortin, P; Gingrich, D M; Gregorich, D T; Hanna, D S; Mohanty, G B; Mukherjee, R; Ong, R A; Oser, S M; Ragan, K; Scalzo, R A; Schütte, D R; Theoret, C G; Tümer, T O; Vincent, F; Zweerink, J A

    2000-01-01

    The Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) is located at the National Solar Thermal Test Facility of Sandia National Laboratories in Albuquerque, New Mexico, USA. The field of solar tracking mirrors (heliostats) around a central receiver tower is used to direct Cherenkov light from atmospheric showers onto secondary mirrors on the tower, which in turn image the light onto cameras of photomultiplier tubes. The STACEE Collaboration has previously reported a detection of the Crab Nebula with approximately 7 standard deviation significance, using 32 heliostats (STACEE-32). This result demonstrates both the viability of the technique and the suitability of the site. We are in the process of completing an upgrade to 48 heliostats (STACEE-48) en route to an eventual configuration using 64 heliostats (STACEE-64) in early 2001. In this paper, we summarize the results obtained on the sensitivity of STACEE-32 and our expectations for STACEE-48 and STACEE-64.

  20. Volcanoes muon imaging using Cherenkov telescopes

    Science.gov (United States)

    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.

  1. QUEST: wide angle Cherenkov light measurements at EAS-TOP

    Science.gov (United States)

    EAS-Top Collaboration; Korosteleva, E. E.; Kuzmichev, L. A.; Prosin, V. V.; Lubsandorzhiev, B. K.

    Wide angle Cherenkov light detectors based upon the QUASAR-370 photo-multipliers have been installed on five Cherenkov telescopes of the EAS-TOP array to study the energy spectrum and composition of primary cosmic rays around the knee . The energy threshold of quasars array was close to that of EAS-TOP electromagnetic detectors array. The first results of joint analysis of Cherenkov and electromagnetic data together with the adequate CORSIKA simulation results are discussed.

  2. Roughness tolerances for Cherenkov telescope mirrors

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

  4. Study of timing performance of Silicon Photomultiplier and application for a Cherenkov detector

    CERN Document Server

    Ahmed, G S M; Marton, J; Suzuki, K

    2010-01-01

    Silicon photomultipliers are very versatile photo detectors due to their high photon detection efficiency, fast response, single photon counting capability, high amplification, and their insensitivity to magnetic fields. At our institute we are studying the performance of these photo detectors at various operating conditions. On the basis of the experience in the laboratory we built a prototype of a timing Cherenkov detector consisting of a quartz radiator with two $3\\times 3$ mm$^2$ MPPCs S10362-33-100C from Hamamatsu Photonics as photodetectors. The MPPC sensors were operated with Peltier cooling to minimize thermal noise and to avoid gain drifts. The test measurements at the DA$\\Phi$NE Beam-Test Facility (BTF) at the Laboratori Nazionali di Frascati (LNF) with pulsed 490 MeV electrons and the results on timing performance with Cherenkov photons are presented.

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

    Science.gov (United States)

    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.

  6. Study of timing performance of silicon photomultiplier and application for a Cherenkov detector

    Science.gov (United States)

    Ahmed, G. S. M.; Bühler, P.; Marton, J.; Suzuki, K.

    2011-02-01

    Silicon photomultipliers are very versatile photo-detectors due to their high photon detection efficiency, fast response, single photon counting capability, high amplification, and their insensitivity to magnetic fields. At our institute we are studying the performance of these photo-detectors at various operating conditions. On the basis of the experience in the laboratory we built a prototype of a timing Cherenkov detector consisting of a quartz radiator with two 3×3 mm 2 MPPCs S10362-33-100C from Hamamatsu Photonics as photo-detectors. The MPPC sensors were operated with Peltier cooling to minimize thermal noise and to avoid gain drifts. The test measurements at the DA Φ NE Beam-Test Facility (BTF) at the Laboratori Nazionali di Frascati (LNF) with pulsed 490 MeV electrons and the results on timing performance with Cherenkov photons are presented.

  7. Recent results on aerogel development for use in Cherenkov counters

    CERN Document Server

    Danilyuk, A F; Savelieva, M D; Bobrovnikov, V S; Buzykaev, A R; Kravchenko, E A; Lavrov, A V; Onuchin, A P

    2002-01-01

    Synthesis of silica aerogel for Cherenkov counters is being studied for more than 10 years at the Boreskov Institute of Catalysis in collaboration with the Budker Institute of Nuclear Physics. Index of refraction, light scattering length and light absorption length are optical characteristics which determine the quality of aerogel Cherenkov counter. These parameters were measured for the aerogel produced. The results are presented.

  8. Radiation of superluminal sources in vacuum

    Energy Technology Data Exchange (ETDEWEB)

    Bolotovskii, B.M. [P.N. Lebedev Physical Institute, Leninsky prospect 53, Moscow 119991 (Russian Federation)]. E-mail: bolot@lpi.ru; Serov, A.V. [P.N. Lebedev Physical Institute, Leninsky prospect 53, Moscow 119991 (Russian Federation)]. E-mail: serov@x4u.levedev.ru

    2006-08-15

    Vavilov-Cherenkov radiation is emitted by a charged body uniformly moving in a medium when the body velocity exceeds that of light in the medium. Therefore, it was believed that Vavilov-Cherenkov radiation is impossible in vacuum, because the velocity of any material body cannot exceed the light velocity in vacuum. However, it is possible to realize distributions of charges and currents which propagate with any given velocity. Such a superluminal distribution can be used as a source of Vavilov-Cherenkov radiation in vacuum.

  9. An Experiment to Demonstrate Cherenkov / Scintillation Signal Separation

    CERN Document Server

    Caravaca, J; Land, B J; Wallig, J; Yeh, M; Gann, G D Orebi

    2016-01-01

    The ability to separately identify the Cherenkov and scintillation light components produced in scintillating mediums holds the potential for a major breakthrough in neutrino detection technology, allowing development of a large, low-threshold, directional detector with a broad physics program. The CHESS (CHErenkov / Scintillation Separation) experiment employs an innovative detector design with an array of small, fast photomultiplier tubes and state-of-the-art electronics to demonstrate the reconstruction of a Cherenkov ring in a scintillating medium based on photon hit time and detected photoelectron density. This paper describes the physical properties and calibration of CHESS along with first results. The ability to reconstruct Cherenkov rings is demonstrated in a water target, and a time precision of 338 +/- 12 ps FWHM is achieved. Monte Carlo based predictions for the ring imaging sensitivity with a liquid scintillator target predict an efficiency for identifying Cherenkov hits of 94 +/- 1% and 81 +/- 1...

  10. The GERDA Muon Veto Cherenkov Detector

    International Nuclear Information System (INIS)

    The GERDA experiment is designed to examine 0νββ of 76Ge with a lifetime of 1026 years. To reach the goal of 10-3 background events/(keV*kg*year), several background reduction techniques will be used. Cosmic muons can produce background in form of particles and radioactivity. To reject them a muon veto system, using the water tank surrounding the GERDA cryostat as an active Cherenkov veto, is built up. The design, simulations and the construction of this veto are described in the poster. (author)

  11. The Cherenkov Telescope Array Large Size Telescope

    CERN Document Server

    Ambrosi, G; Baba, H; Bamba, A; Barceló, M; de Almeida, U Barres; Barrio, J A; Bigas, O Blanch; Boix, J; Brunetti, L; Carmona, E; Chabanne, E; Chikawa, M; Colin, P; Conteras, J L; Cortina, J; Dazzi, F; Deangelis, A; Deleglise, G; Delgado, C; Díaz, C; Dubois, F; Fiasson, A; Fink, D; Fouque, N; Freixas, L; Fruck, C; Gadola, A; García, R; Gascon, D; Geffroy, N; Giglietto, N; Giordano, F; Grañena, F; Gunji, S; Hagiwara, R; Hamer, N; Hanabata, Y; Hassan, T; Hatanaka, K; Haubold, T; Hayashida, M; Hermel, R; Herranz, D; Hirotani, K; Inoue, S; Inoue, Y; Ioka, K; Jablonski, C; Kagaya, M; Katagiri, H; Kishimoto, T; Kodani, K; Kohri, K; Konno, Y; Koyama, S; Kubo, H; Kushida, J; Lamanna, G; Flour, T Le; López-Moya, M; López, R; Lorenz, E; Majumdar, P; Manalaysay, A; Mariotti, M; Martínez, G; Martínez, M; Mazin, D; Miranda, J M; Mirzoyan, R; Monteiro, I; Moralejo, A; Murase, K; Nagataki, S; Nakajima, D; Nakamori, T; Nishijima, K; Noda, K; Nozato, A; Ohira, Y; Ohishi, M; Ohoka, H; Okumura, A; Orito, R; Panazol, J L; Paneque, D; Paoletti, R; Paredes, J M; Pauletta, G; Podkladkin, S; Prast, J; Rando, R; Reimann, O; Ribó, M; Rosier-Lees, S; Saito, K; Saito, T; Saito, Y; Sakaki, N; Sakonaka, R; Sanuy, A; Sasaki, H; Sawada, M; Scalzotto, V; Schultz, S; Schweizer, T; Shibata, T; Shu, S; Sieiro, J; Stamatescu, V; Steiner, S; Straumann, U; Sugawara, R; Tajima, H; Takami, H; Tanaka, S; Tanaka, M; Tejedor, L A; Terada, Y; Teshima, M; Totani, T; Ueno, H; Umehara, K; Vollhardt, A; Wagner, R; Wetteskind, H; Yamamoto, T; Yamazaki, R; Yoshida, A; Yoshida, T; Yoshikoshi, T

    2013-01-01

    The two arrays of the Very High Energy gamma-ray observatory Cherenkov Telescope Array (CTA) will include four Large Size Telescopes (LSTs) each with a 23 m diameter dish and 28 m focal distance. These telescopes will enable CTA to achieve a low-energy threshold of 20 GeV, which is critical for important studies in astrophysics, astroparticle physics and cosmology. This work presents the key specifications and performance of the current LST design in the light of the CTA scientific objectives.

  12. Gadolinium study for a water Cherenkov detector

    CERN Document Server

    Kibayashi, Atsuko

    2009-01-01

    Modification of large water Cherenkov detectors by addition of gadolinium has been proposed. The large cross section for neutron capture on Gd will greatly improve the sensitivity to antielectron neutrinos from supernovae and reactors. A five-year project to build and develop a prototype detector based on Super-Kamiokande (SK) has started. We are performing various studies, including a material soak test in Gd solution, light attenuation length measurements, purification system development, and neutron tagging efficiency measurements using SK data and a Geant4-based simulation. We present an overview of the project and the recent R&D results.

  13. Modelling and study of the Cherenkov effect

    Energy Technology Data Exchange (ETDEWEB)

    Mishev, A. E-mail: libor.makovicka@pu-pm.univ-fcomte.fr; Duverger, E.; Makovicka, L.; Stamenov, J

    2001-06-01

    Studies at the Institute for Nuclear Research and Nuclear Energy particularly in regard to cosmic ray detection and construction of the Muonic Cherenkov telescope at the University of Blagoevgrad indicate a need for the development of a theoretical model based on observed phenomena and a refinement of this for detection system optimisation. This was introduced in the EGS4 code system. The first simulations consecrate on a number of different geometries of the water tank in total reflection. The model was compared with experimental data involving a {sup 60}Co gamma source and the telescope. (author)

  14. Atmospheric Cherenkov Gamma-ray Telescopes

    CERN Document Server

    Holder, Jamie

    2015-01-01

    The stereoscopic imaging atmospheric Cherenkov technique, developed in the 1980s and 1990s, is now used by a number of existing and planned gamma-ray observatories around the world. It provides the most sensitive view of the very high energy gamma-ray sky (above 30 GeV), coupled with relatively good angular and spectral resolution over a wide field-of-view. This Chapter summarizes the details of the technique, including descriptions of the telescope optical systems and cameras, as well as the most common approaches to data analysis and gamma-ray reconstruction.

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

    Science.gov (United States)

    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.

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

    CERN Document Server

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

    2011-01-01

    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 $\\pm$ 0.02 for 4-Methylumbelliferone, stable to within 0.5% over 50 days, 1.37 $\\pm$ 0.03 for Carbostyril-124, and 1.20 $\\pm$ 0.02 for Amino-G Salt. The response of 4-Methylumbelliferone was modele...

  17. A microwave inverse Cherenkov accelerator (MICA)

    Science.gov (United States)

    Zhang, T. B.; Marshall, T. C.

    1996-02-01

    By "inverting" the stimulated Cherenkov effect to stimulated Cherenkov absorption, it is possible to build an electron accelerator device driven by high power microwaves that propagate in a slow-wave TM mode (axial E-field). In this paper, we have solved for the wave dispersion in the structure, found the field distributions, and then used the Lorentz force equations to obtain the motion of a group of electrons distributed in radius and velocity. We find the radial forces are focusing. Electrons in a well-defined filament ( r < 0.5 mm) remain collimated and do not strike the dielectric. By using the 15 MW of rf power available at 2.865 GHz, we can accelerate an electron beam (˜6 MeV, few ps pulses) to energy ˜16 MeV. This results in a relatively compact structure that has the advantage of a smooth-bore design and no need of magnetic focusing. The techniques for improving the dielectric breakdown the surface should permit axial fields in the range of 100-200 kV/cm.

  18. The high-altitude water Cherenkov Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Mostafa, Miguel A., E-mail: miguel@psu.edu [Department of Physics, Colorado State University, Ft Collins, CO (United States)

    2014-07-01

    The High-Altitude Water Cherenkov (HAWC) observatory is a large field of view, continuously operated, TeV γ -ray experiment under construction at 4,100ma.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 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. (author)

  19. Roughness tolerances for Cherenkov telescope mirrors

    CERN Document Server

    Tayabaly, K; Canestrari, R; Bonnoli, G; Lavagna, M; Pareschi, G

    2016-01-01

    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 ...

  20. The High Altitude Water Cherenkov Observatory

    CERN Document Server

    ,

    2013-01-01

    The High Altitude Water Cherenkov (HAWC) observatory is a large field of view, continuously operated, TeV gamma-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 transient and steady emissions, to study the Galactic diffuse emission at TeV energies, and to measure or constrain the TeV spectra of GeV gamma-ray sources. In addition, HAWC will be the only ground-based instrument capable of detecting prompt emission from gamma-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 thirty WCDs (forming an array approximately the size of Milagro) were deployed in Summer...

  1. A Medium Sized Schwarzschild-Couder Cherenkov Telescope Mechanical Design Proposed for the Cherenkov Telescope Array

    CERN Document Server

    Byrum, K; Benbow, W; Cameron, R; Criswell, S; Errando, M; Guarino, V; Kaaret, P; Kieda, D; Mukherjee, R; Naumann, D; Nieto, D; Northrop, R; Okumura, A; Roache, E; Rousselle, J; Schlenstedt, S; Sternberger, R; Vassiliev, V; Wakely, S; Zhao, H

    2015-01-01

    The Cherenkov Telescope Array (CTA) is an international next-generation ground-based gamma-ray observatory. CTA will be implemented as southern and northern hemisphere arrays of tens of small, medium and large-sized imaging Cherenkov telescopes with the goal of improving the sensitivity over the current-generation experiments by an order of magnitude. CTA will provide energy coverage from ~20 GeV to more than 300 TeV. The Schwarzschild-Couder (SC) medium size (9.5m) telescopes will feature a novel aplanatic two-mirror optical design capable of accommodating a wide field-of-view with significantly improved angular resolution as compared to the traditional Davies-Cotton optical design. A full-scale prototype SC medium size telescope structure has been designed and will be constructed at the Fred Lawrence Whipple Observatory in southern Arizona during the fall of 2015. concentrate on the novel features of the design.

  2. Comparison of Cherenkov excited fluorescence and phosphorescence molecular sensing from tissue with external beam irradiation.

    Science.gov (United States)

    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

  3. Comparison of Cherenkov excited fluorescence and phosphorescence molecular sensing from tissue with external beam irradiation

    Science.gov (United States)

    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

  4. Cherenkov light-based beam profiling for ultrarelativistic electron beams

    Energy Technology Data Exchange (ETDEWEB)

    Adli, E., E-mail: Erik.Adli@fys.uio.no [Department of Physics, University of Oslo, N-0316 Oslo (Norway); SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Gessner, S.J.; Corde, S.; Hogan, M.J. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Bjerke, H.H. [SLAC National Accelerator Laboratory, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); Department of Physics, Norwegian University of Science and Technology, N-7491 Trondheim (Norway)

    2015-05-21

    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. 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. We report on the measured performance of this profile monitor.

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

    International Nuclear Information System (INIS)

    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

  6. The Gamma-ray Cherenkov Telescope for the Cherenkov Telescope Array

    CERN Document Server

    Tibaldo, L; Allan, D; Amans, J -P; Armstrong, T P; Balzer, A; Berge, D; Boisson, C; Bousquet, J -J; Brown, A M; Bryan, M; Buchholtz, G; Chadwick, P M; Costantini, H; Cotter, G; Daniel, M K; De Franco, A; De Frondat, F; Dournaux, J -L; Dumas, D; Ernenwein, J -P; Fasola, G; Funk, S; Gironnet, J; Graham, J A; Greenshaw, T; Hervet, O; Hidaka, N; Hinton, J A; Huet, J -M; Jankowsky, D; Jegouzo, I; Jogler, T; Kraus, M; Lapington, J S; Laporte, P; Lefaucheur, J; Markoff, S; Melse, T; Mohrmann, L; Molyneux, P; Nolan, S J; Okumura, A; Osborne, J P; Parsons, R D; Rosen, S; Ross, D; Rowell, G; Rulten, C B; Sato, Y; Sayede, F; Schmoll, J; Schoorlemmer, H; Servillat, M; Sol, H; Stamatescu, V; Stephan, M; Stuik, R; Sykes, J; Tajima, H; Thornhill, J; Trichard, C; Vink, J; Watson, J J; White, R; Yamane, N; Zech, A; Zink, A; Zorn, J

    2016-01-01

    The Cherenkov Telescope Array (CTA) is a forthcoming ground-based observatory for very-high-energy gamma rays. CTA will consist of two arrays of imaging atmospheric Cherenkov telescopes in the Northern and Southern hemispheres, and will combine telescopes of different types to achieve unprecedented performance and energy coverage. The Gamma-ray Cherenkov Telescope (GCT) is one of the small-sized telescopes proposed for CTA to explore the energy range from a few TeV to hundreds of TeV with a field of view $\\gtrsim 8^\\circ$ and angular resolution of a few arcminutes. The GCT design features dual-mirror Schwarzschild-Couder optics and a compact camera based on densely-pixelated photodetectors as well as custom electronics. In this contribution we provide an overview of the GCT project with focus on prototype development and testing that is currently ongoing. We present results obtained during the first on-telescope campaign in late 2015 at the Observatoire de Paris-Meudon, during which we recorded the first Cher...

  7. Calibration of the Cherenkov Telescope Array

    CERN Document Server

    Gaug, Markus; Berge, David; Reyes, Raquel de los; Doro, Michele; Foerster, Andreas; Maccarone, Maria Concetta; Parsons, Dan; van Eldik, Christopher

    2015-01-01

    The construction of the Cherenkov Telescope Array is expected to start soon. We will present the baseline methods and their extensions currently foreseen to calibrate the observatory. These are bound to achieve the strong requirements on allowed systematic uncertainties for the reconstructed gamma-ray energy and flux scales, as well as on the pointing resolution, and on the overall duty cycle of the observatory. Onsite calibration activities are designed to include a robust and efficient calibration of the telescope cameras, and various methods and instruments to achieve calibration of the overall optical throughput of each telescope, leading to both inter-telescope calibration and an absolute calibration of the entire observatory. One important aspect of the onsite calibration is a correct understanding of the atmosphere above the telescopes, which constitutes the calorimeter of this detection technique. It is planned to be constantly monitored with state-of-the-art instruments to obtain a full molecular and...

  8. Observer Access to the Cherenkov Telescope Array

    CERN Document Server

    Knödlseder, Jürgen; Boisson, Catherine; Brau-Nogué, Sylvie; Deil, Christoph; Khélifi, Bruno; Mayer, Michael; Walter, Roland

    2015-01-01

    The Cherenkov Telescope Array (CTA), a ground-based facility for very-high-energy (VHE) gamma-ray astronomy, will operate as an open observatory, serving a wide scientific community to explore and to study the non-thermal universe. Open community access is a novelty in this domain, putting a challenge on the implementation of services that make VHE gamma-ray astronomy as accessible as any other waveband. We present here the design of the CTA Observer Access system that comprises support of scientific users, dissemination of data and software, tools for scientific analysis, and the system to submit observing proposals. We outline the scientific user workflows and provide the status of the current developments.

  9. TORCH - a Cherenkov-based time-of-flight detector

    CERN Document Server

    van Dijk, M W U; Cowie, E N; Cussans, D; D' Ambrosio, C; Forty, R; Frei, C; Gys, T; Piedigrossi, D; Castillo Garcia, L; Fopma, J; Gao, R; Harnew, N; Keri, T

    2014-01-01

    TORCH is an innovative high-precision time-of-flight system to provide particle identification in the difficult intermediate momentum region up to 10 GeV/c. It is also suitable for large-area applications. The detector provides a time-of-flight measurement from the imaging of Cherenkov photons emitted in a 1 cm thick quartz radiator. The photons propagate by total internal reflection to the edge of the quartz plate, where they are focused onto an array of photon detectors at the periphery. A time-of-flight resolution of about 10–15 ps per incident charged particle needs to be achieved for a three sigma kaon–pion separation up to 10 GeV/c momentum for the TORCH located 9.5 m from the interaction point. Given ∼ 30 detected photons per incident charged particle, this requires measuring the time-of-arrival of individual photons to about 70 ps. This paper will describe the design of a TORCH prototype involving a number of ground-breaking and challenging techniques.

  10. WIMP search and a Cherenkov detector prototype for ILC polarimetry

    Energy Technology Data Exchange (ETDEWEB)

    Bartels, Christoph

    2011-10-15

    The planned International Linear Collider (ILC) will be an essential experiment to precisely determine the properties and structure of physics at the TeV scale. An important feature of the ILC is the possibility to use polarized electrons and positrons. In part 1 of this thesis, a model independent search for Weakly Interacting Massive Particles (WIMPs) at ILC is presented. The signal channel under study is direct WIMP pair production with associated Initial State Radiation (ISR), e{sup +}e{sup -} {yields} {chi}{chi}{gamma}, where the WIMPs leave the detector without any further interaction, and only the emitted photon is detected. From the energy spectrum of the detected photons the coupling structure, cross sections, masses and the quantum number of the dominant partial wave in the production process can be inferred. The analysis includes the dominant SM, as well as machine-induced backgrounds, and is performed using a full simulation of the ILD detector concept. For an integrated luminosity of L=500 fb{sup -1}, the signal cross sections can be measured to a precision of 3%, dominated by systematic uncertainties on the polarization measurement of the initial electrons and positrons. Masses can be measured to a precision of up to 2% by a comparison of the data photon spectrum to parametrized template spectra. In part 2 of this thesis, a Cherenkov detector prototype for Compton polarimetry at ILC is presented. For the polarization measurement a systematic uncertainty of {delta} P/P = 0.25% or better is envisioned. To achieve this goal, the Cherenkov detector has to be precisely aligned with the fan of Compton scattered electrons and its signal response needs to be highly linear. For the detector prototype data driven alignment strategies have been developed by comparing data recorded at the Elsa accelerator in Bonn, Germany, with detailed Geant4 simulations. With the use of multi-anode photomultipliers, data driven alignment strategies promise to provide the

  11. Observation of Optical Flashes of the Night Star Sky on the Atmospheric Cherenkov Installation Tunka-13

    OpenAIRE

    Gress, O. A.; Gress, T. I.; Pan'kov, L. V.; Parfenov, Yu. V.; Semeney, Yu. A.; Kuzmichev, L. A.

    2000-01-01

    Experiment on the study of fluctuation of night glow is conducted on the base of 13 module atmospheric Cherenkov telescope TUNKA-13.Basic task of TUNKA-13 is registration of light from Extended Air Shower (EAS) initiated by primary cosmic particles. Observation of light flashes radiating in nigght atmosphere is one more experiment which is run for TUNKA-13 to study the background condition for EAS registration. At a period from December 1997 on a May 1998 was registered 149 light flashes of r...

  12. TORCH - Cherenkov and Time-of-Flight PID Detector for the LHCb Upgrade at CERN

    Science.gov (United States)

    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.

  13. The response of wavelength shifting panels in large water Cherenkov systems

    International Nuclear Information System (INIS)

    This paper describes a series of tests performed with a panel Bicron wavelength shifting acrylic plastic (BC-480) coupled to an EMI 9623B photomultiplier tube. The aim was to effectively increase the cathode coverage and its sensitivity to incident Cherenkov radiation, so that such a system could be employed in a solar neutrino detector. Measurements of the uniformity and effective efficiency of the system have been made and compared with the results of various simulation runs. The effects of side mirrors, back reflector, water interface and possible shaping of the panel to enhance its response are also assessed. (orig.)

  14. Proximity focusing RICH detector based on multilayer silica aerogel radiator

    CERN Document Server

    De Leo, R; Bellunato, T; Calvi, M; Cisbani, E; Cusanno, F; Garibaldi, F; Lagamba, L; Marra, M; Marrone, S; Matteuzzi, C; Musico, P; Nappi, E; Perego, D L; Torrioli, S; Vilardi, I

    2010-01-01

    The performance of a proximity focusing Ring Imaging Cherenkov detector equipped with a radiator of silica aerogel is presented. The aerogel tile used is a monolith with variable index of refraction. Cherenkov photons are detected with high granularity by eight Hamamatsu H9500 flat panel multi anode phototubes.

  15. Wavelet Imaging Cleaning Method for Atmospheric Cherenkov Telescopes

    OpenAIRE

    Lessard, R. W.; Cayón, L.; Sembroski, G.H.; Gaidos, J. A.

    2001-01-01

    We present a new method of image cleaning for imaging atmospheric Cherenkov telescopes. The method is based on the utilization of wavelets to identify noise pixels in images of gamma-ray and hadronic induced air showers. This method selects more signal pixels with Cherenkov photons than traditional image processing techniques. In addition, the method is equally efficient at rejecting pixels with noise alone. The inclusion of more signal pixels in an image of an air shower allows for a more ac...

  16. Fast timing and trigger Cherenkov detector for collider experiments

    OpenAIRE

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

    2016-01-01

    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 ob...

  17. On the "Non-Restricted special Relativity" theory (NRR), and further comments on "Cherenkov vs X-waves"

    CERN Document Server

    Zamboni-Rached, Michel; Besieris, Ioannis M

    2012-01-01

    Our aim in this paper is to recall some essential points of "Extended special Relativity", now more correctly called "Non-Restricted special Relativity" theory (NRR), and in particular of the extended Maxwell Equations; as well as to set forth some further comments on the basic differences between Cherenkov Radiation and the so-called X-shaped Waves, met within the more recent realm of the Non-diffracting Waves (also known as Localized Waves). The occasion is furnished by some very recent Seshadri's comments[1] on a previous article of ours, titled "Cherenkov radiation versus X-shaped localized waves" (see[2], and arXiv:0807.4301[physics.optics]), and not less on NRR itself. OCIS codes: 320.5550; 350.7420; 070.7345; 350.5500; 070.0070; 100.7410; 050.050; 000.1600; 000.2690; 000.6800; 250.5530; 260.0260. PACS nos.: 41.60.Bq; 03.50.De; 03.30.+p; 41.20;Jb; 04.30.Db; 42.25.-p; 42.25.Fx; 47.35.Rs. Keywords: Non-diffracing Waves; Localized Waves; Cherenkov radiation; X-shaped waves; Wave equations; Bessel beams; Su...

  18. Performance of a hybrid photon detector prototype with electrostatic cross-focussing and integrated silicon Pixel readout for Cherenkov ring detection

    CERN Document Server

    Alemi, M; Bibby, J H; Campbell, M; Duane, A; Easo, S; Gys, Thierry; Halley, A W; Piedigrossi, D; Puertolas, D; Rosso, E; Simmons, B; Snoeys, W; Websdale, David M; Wotton, S A; Wyllie, Ken H

    1999-01-01

    We report on the first test beam performance of a hybrid photon detector prototype, using binary readout electronics, intended for use in the ring imaging Cherenkov detectors of the LHCb experiment at the CERN Large Hadron Collider. The photon detector is based on a cross-focussed image intensifier tube geometry. The anode consists of a silicon pixel array bump-bonded to a binary readout chip with matching pixel electronics. The detector has been installed in a quarter-scale prototype vessel of the LHCb ring imaging Cherenkov system. Focussed ring images produced by 120 GeV/c negative pions traversing an air radiator have been recorded. The observed light yield and Cherenkov angle resolution are discussed.

  19. Radiation spectrum of an electron moving in a spiralin medium

    Directory of Open Access Journals (Sweden)

    A.V.Konstantinovich

    2007-01-01

    Full Text Available The action of the Doppler effect on the particularities of radiation power spectral distribution of an electron moving in a spiral in a medium has been investigated near the Cherenkov threshold. The fine structure of the electromagnetic radiation spectrum at the Cherenkov threshold and the synchrotron-Cherenkov radiation spectrum for an electron moving along a spiral with non-relativistic longitudinal component of the velocity (i.e., the component parallel to the magnetic induction vector in a transparent isotropic medium have been obtained and studied.

  20. Sensivity studies for the Cherenkov Telescope Array

    Science.gov (United States)

    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.

  1. Measurements of Cherenkov Photons with Silicon Photomultipliers

    CERN Document Server

    Korpar, S; Chagani, H; Dolenec, R; Hara, K; Iijima, T; Krizan, P; Nishida, S; Pestotnik, R; Stanovnik, A

    2008-01-01

    A novel photon detector, the Silicon Photomultiplier (SiPM), has been tested in proximity focusing Ring Imaging Cherenkov (RICH) counters that were exposed to cosmic-ray particles in Ljubljana, and a 2 GeV electron beam at the KEK research facility. This type of RICH detector is a candidate for the particle identification detector upgrade of the BELLE detector at the KEK B-factory, for which the use of SiPMs, microchannel plate photomultiplier tubes or hybrid avalanche photodetectors, rather than traditional Photomultiplier Tubes (PMTs) is essential due to the presence of high magnetic fields. In both experiments, SiPMs are found to compare favourably with PMTs, with higher photon detection rates per unit area. Through the use of hemispherical and truncated pyramid light guides to concentrate photons onto the active surface area, the light yield increases significantly. An estimate of the contribution to dark noise from false coincidences between SiPMs in an array is also presented.

  2. Detection of tau neutrinos by imaging air Cherenkov telescopes

    Science.gov (United States)

    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.

  3. GAW (Gamma Air Watch) a novel imaging Cherenkov telescope

    CERN Document Server

    Cusumano, G; Biondo, B; Catalano, O; Giarrusso, S; Gugliotta, G; La Fata, L; Maccarone, M C; Mangano, A; Mineo, T; Russo, F; Sacco, B

    2001-01-01

    GAW (Gamma Air Watch) is a new imaging Cherenkov telescope designed for observation of very high-energy gamma-ray sources. GAW will be equipped with a 3 meter diameter Fresnel lens as light collector and with an array of 300 multi-anode photomultipliers at the focal plane. The pixel size will be 4 arcmin wide for a total field of view of 10.5 degrees. Whith respect to the planned imaging Cherenkov telescopes (CANGAROO III, HESS, MAGIC, VERITAS) GAW follows a different approach for what concerns both the optical system and the detection working mode: the Cherenkov light collector is a single acrylic flat Fresnel lens (instead of mirrors) that allows to achieve wide field of view; the photomultipliers operate in single photoelectron counting mode (instead of charge integration). The single photoelectron counting mode allows to reach a low energy threshold of ~200 GeV, in spite of the relatively small dimension of the GAW optic system.

  4. Lunar Imaging and Ionospheric Calibration for the Lunar Cherenkov Technique

    CERN Document Server

    McFadden, Rebecca; Mevius, Maaijke

    2013-01-01

    The Lunar Cherenkov technique is a promising method for UHE neutrino and cosmic ray detection which aims to detect nanosecond radio pulses produced during particle interactions in the Lunar regolith. For low frequency experiments, such as NuMoon, the frequency dependent dispersive effect of the ionosphere is an important experimental concern as it reduces the pulse amplitude and subsequent chances of detection. We are continuing to investigate a new method to calibrate the dispersive effect of the ionosphere on lunar Cherenkov pulses via Faraday rotation measurements of the Moon's polarised emission combined with geomagnetic field models. We also extend this work to include radio imaging of the Lunar surface, which provides information on the physical and chemical properties of the lunar surface that may affect experimental strategies for the lunar Cherenkov technique.

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

    Science.gov (United States)

    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 .

  6. Separation of Scintillation and Cherenkov Lights in Linear Alkyl Benzene

    CERN Document Server

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

    2015-01-01

    To separate scintillation and Cherenkov lights in water-based liquid scintillator detectors is a desired feature for future neutrino and proton decay researches. Linear alkyl benzene (LAB) is one important ingredient of a water-based liquid scintillator being developed. In this paper we observed a good separation of scintillation and Cherenkov lights in an LAB sample. The rising and decay times of the scintillation light of the LAB were measured to be $(7.7\\pm3.0)\\ \\rm{ns}$ and $(36.6\\pm2.4)\\ \\rm{ns}$, respectively, while the full width [-3$\\sigma$, 3$\\sigma$] of the Cherenkov light was 12 ns dominated by the time resolution of our photomultiplier tubes. The light yield of the scintillation was measured to be $(1.01\\pm0.12)\\times10^3\\ \\rm{photons}/\\rm{MeV}$.

  7. The first GCT camera for the Cherenkov Telescope Array

    CERN Document Server

    De Franco, A.; Allan, D.; Armstrong, T.; Ashton, T.; Balzer, A.; Berge, D.; Bose, R.; Brown, A.M.; Buckley, J.; Chadwick, P.M.; Cooke, P.; Cotter, G.; Daniel, M.K.; Funk, S.; Greenshaw, T.; Hinton, J.; Kraus, M.; Lapington, J.; Molyneux, P.; Moore, P.; Nolan, S.; Okumura, A.; Ross, D.; Rulten, C.; Schmoll, J.; Schoorlemmer, H.; Stephan, M.; Sutcliffe, P.; Tajima, H.; Thornhill, J.; Tibaldo, L.; Varner, G.; Watson, J.; Zink, A.

    2015-01-01

    The Gamma Cherenkov Telescope (GCT) is proposed to be part of the Small Size Telescope (SST) array of the Cherenkov Telescope Array (CTA). The GCT dual-mirror optical design allows the use of a compact camera of diameter roughly 0.4 m. The curved focal plane is equipped with 2048 pixels of ~0.2{\\deg} angular size, resulting in a field of view of ~9{\\deg}. The GCT camera is designed to record the flashes of Cherenkov light from electromagnetic cascades, which last only a few tens of nanoseconds. Modules based on custom ASICs provide the required fast electronics, facilitating sampling and digitisation as well as first level of triggering. The first GCT camera prototype is currently being commissioned in the UK. On-telescope tests are planned later this year. Here we give a detailed description of the camera prototype and present recent progress with testing and commissioning.

  8. The Atmospheric Monitoring Strategy for the Cherenkov Telescope Array

    CERN Document Server

    Daniel, M K

    2015-01-01

    The Imaging Atmospheric Cherenkov Technique (IACT) is unusual in astronomy as the atmosphere actually forms an intrinsic part of the detector system, with telescopes indirectly detecting very high energy particles by the generation and transport of Cherenkov photons deep within the atmosphere. This means that accurate measurement, characterisation and monitoring of the atmosphere is at the very heart of successfully operating an IACT system. The Cherenkov Telescope Array (CTA) will be the next generation IACT observatory with an ambitious aim to improve the sensitivity of an order of magnitude over current facilities, along with corresponding improvements in angular and energy resolution and extended energy coverage, through an array of Large (23m), Medium (12m) and Small (4m) sized telescopes spread over an area of order ~km$^2$. Whole sky coverage will be achieved by operating at two sites: one in the northern hemisphere and one in the southern hemisphere. This proceedings will cover the characterisation of...

  9. Research and Development for a Gadolinium Doped Water Cherenkov Detector

    CERN Document Server

    Renshaw, Andrew

    2012-01-01

    The proposed introduction of a soluble gadolinium (Gd) compound into water Cherenkov detectors can result in a high efficiency for the detection of free neutrons capturing on the Gd. The delayed 8 MeV gamma cascades produced by these captures, in coincidence with a prompt positron signal, serve to uniquely identify electron antineutrinos interacting via inverse beta decay. Such coincidence detection can reduce backgrounds, allowing a large Gd-enhanced water Cherenkov detector to make the first observation of supernova relic neutrinos and high precision measurements of Japan's reactor antineutrino flux, while still allowing for all current physics studies to be continued. Now, a dedicated Gd test facility is operating in the Kamioka Mine. This new facility houses everything needed to successfully operate a Gd doped water Cherenkov detector. Successful running of this facility will demonstrate that adding Gd salt to SK is both safe for the detector and is capable of delivering the expected physics benefits.

  10. The GCT camera for the Cherenkov Telescope Array

    CERN Document Server

    Brown, Anthony M; Allan, D; Amans, J P; Armstrong, T P; Balzer, A; Berge, D; Boisson, C; Bousquet, J -J; Bryan, M; Buchholtz, G; Chadwick, P M; Costantini, H; Cotter, G; Daniel, M K; De Franco, A; De Frondat, F; Dournaux, J -L; Dumas, D; Fasola, G; Funk, S; Gironnet, J; Graham, J A; Greenshaw, T; Hervet, O; Hidaka, N; Hinton, J A; Huet, J -M; Jegouzo, I; Jogler, T; Kraus, M; Lapington, J S; Laporte, P; Lefaucheur, J; Markoff, S; Melse, T; Mohrmann, L; Molyneux, P; Nolan, S J; Okumura, A; Osborne, J P; Parsons, R D; Rosen, S; Ross, D; Rowell, G; Sato, Y; Sayede, F; Schmoll, J; Schoorlemmer, H; Servillat, M; Sol, H; Stamatescu, V; Stephan, M; Stuik, R; Sykes, J; Tajima, H; Thornhill, J; Tibaldo, L; Trichard, C; Vink, J; Watson, J J; White, R; Yamane, N; Zech, A; Zink, A; Zorn, J

    2016-01-01

    The Gamma-ray Cherenkov Telescope (GCT) is proposed for the Small-Sized Telescope component of the Cherenkov Telescope Array (CTA). GCT's dual-mirror Schwarzschild-Couder (SC) optical system allows the use of a compact camera with small form-factor photosensors. The GCT camera is ~0.4 m in diameter and has 2048 pixels; each pixel has a ~0.2 degree angular size, resulting in a wide field-of-view. The design of the GCT camera is high performance at low cost, with the camera housing 32 front-end electronics modules providing full waveform information for all of the camera's 2048 pixels. The first GCT camera prototype, CHEC-M, was commissioned during 2015, culminating in the first Cherenkov images recorded by a SC telescope and the first light of a CTA prototype. In this contribution we give a detailed description of the GCT camera and present preliminary results from CHEC-M's commissioning.

  11. Cherenkov and Scintillation Light Separation in Organic Liquid Scintillators

    CERN Document Server

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

    2016-01-01

    The CHErenkov / Scintillation Separation experiment (CHESS) has been used to demonstrate the separation of Cherenkov and scintillation light in both linear alkylbenzene (LAB) and LAB with 2g/L of PPO as a fluor (LAB/PPO). This is the first such demonstration for the more challenging LAB/PPO cocktail and improves on previous results for LAB. A time resolution of 338 +/- 12 ps FWHM results in an efficiency for identifying Cherenkov photons in LAB/PPO of 70 +/- 3% and 63 +/- 8% for time- and charge-based separation, respectively, with scintillation contamination of 36 +/- 5% and 38 +/- 4%. LAB/PPO data is consistent with a rise time of 0.75 +/- 0.25 ns.

  12. The GERDA muon veto Cherenkov detector

    International Nuclear Information System (INIS)

    The GERmanium Detector Array, GERDA, is a new experiment designed to examine the neutrinoless double beta decay 0νββ of 76Ge which has a lifetime of at least 1026 years and a single energy deposition of 2039 keV. To reach the goal of 10-3 background events/(keVkgy), several background reduction techniques like anti-coincidence and pulse shape analysis will be used. Cosmic muons can produce background in form of particles and radioactivity. To reject them, two independent detector systems will be integrated in GERDA. One of these is a Cherenkov muon veto detector, that uses the water tank around the cryostat in which the crystals will be operated. It is equipped with 66 photomultipliers (PMTs) with 8 in. diameter. The PMT distribution was found via extensive Monte Carlo studies to reach the highest efficiencies for dangerous muons (these are muons that cause an energy deposition of around 2 MeV in the germanium detectors), even though the PMTs cover less than 0.1% of the water tank surface. High efficiencies depend strongly on the amount of detected photons. For this, as many surfaces as possible will be covered with 'VM2000', a highly reflective foil from 3 M. This foil has a high reflectivity in a wide range of wavelength and it also shifts photons from the UV into the optical range. It, more or less, doubles the amount of detectable photons, because the photomultipliers used, have an detection maximum between 370 and 400 nm. Thus, a detection efficiency of 98% should be easily achieved.

  13. Module of silicon photomultipliers as a detector of individual Cherenkov photons

    Science.gov (United States)

    Pestotnik, Rok; Dolenec, Rok; Korpar, Samo; Križan, Peter; Stanovnik, Aleš

    2011-05-01

    We have studied the possibility of using silicon photomultipliers as single photon detectors in a proximity focusing RICH with aerogel radiator. Such a counter is considered for the upgrade of the Belle detector. The main advantage of silicon over conventional photomultiplier tubes is their operation in high magnetic fields. Their disadvantage is the relatively high dark noise count rate (≈MHz/mm2) which can be overcome by using a narrow time window in the data acquisition. A module, consisting of 64 (8×8) Hamamatsu MPPC S10362-11-100P silicon photomultipliers, has been designed, constructed and tested with Cherenkov photons emitted in an aerogel radiator by 120 GeV/ c pions from the CERN T4-H6 beam. To increase the signal-to-noise ratio, i.e. to increase the effective surface on which light is detected, light concentrators have been employed.

  14. SU-E-T-186: Feasibility Study of Glass Cherenkov Detector for Prompt Gamma Detection in Proton Therapy

    International Nuclear Information System (INIS)

    Purpose: To simulate a Cherenkov glass detector system utilizing prompt gamma (PG) technique to quantify range uncertainties in proton radiation therapy. Methods: A simulation of high energy photons typically produced in proton interactions with materials incident onto a block of Cherenkov glass was performed with the Geant4 toolkit. The standard electromagnetic package was used along with several decay modules (G4Decay, G4DecayPhysics, and G4RadioactiveDecayPhysics) and the optical photon components (G4OpticalPhysics). Our setup included a pencil beam consisting of a hundred thousand 6 MeV photons (approximately the deexcitation energy released from 16O) incident onto a 2.5 ⊗ 2.5 ⊗ 1.5 cm3 of a Cherenkov glass (7.2 g of In2O3 + 90 g cladding, density of 2.82 g/cm3, Zeff = 33.7, index of refraction 1.56). The energy deposited from incident 6 MeV photons as well as secondary electrons and resulting optical photons were recorded. Results: The energy deposited by 6 MeV photons in glass material showed several peaks that included the photoelectric, the single and double escape peaks. About 11% of incident photons interacted with glass material to deposit energy. Most of the photons collected were in the region of double escape peak (approximately 4.98 MeV). The secondary electron spectrum produced from incident photons showed a high energy peak located near 6 MeV and a sharp peak located ∼120 keV with a continuous distribution between these two points. The resulting Cherenkov photons produced showed a continuous energy distribution between 2 and 5 eV with a slight increase in yield beginning about 3 eV. The amount of Cherenkov photons produced per interacting incident 6 MeV photon was ∼240.7. Conclusion: This study suggests the viability of utilizing the Cherenkov glass material as a possible prompt gamma photon detection device. Future work will include optimization of the detector system to maximize photon detection efficiency

  15. Typical atmospheric aerosol behavior at the Cherenkov Telescope Array candidate sites in Argentina

    CERN Document Server

    Piacentini, Rubén D; Micheletti, María I; Salum, Graciela M; Maya, Javier; Mancilla, Alexis; García, Beatriz

    2013-01-01

    Aerosols from natural and antropogenic sources are one of the atmospheric components that have the largest spacial-temporal variability, depending on the type (land or ocean) surface, human activity and climatic conditions (mainly temperature and wind). Since Cherenkov photons generated by the incidence of a primary ultraenergetic cosmic gamma photon have a spectral intensity distribution concentrated in the UV and visible ranges [Hillas AM. Space Science Reviews, 75, 17-30, 1996], it is important to know the aerosol concentration and its contribution to atmospheric radiative transfer. We present results of this concentration measured in typical rather calm (not windy) days at San Antonio de los Cobres (SAC) and El Leoncito/CASLEO proposed Argentinean Andes range sites for the placement of the Cherenkov Telescope Array (CTA). In both places, the aerosol concentration has a peak in the 2.5-5.0$\\mu$m range of the mean aerosol diameter and a very low mean total concentration of 0.097$\\mu$g/m$^3$ (0.365$\\mu$g/m$^...

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

    Science.gov (United States)

    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.

  17. Multi-anode photon-multiplier readout electronics for the LHCb ring imaging Cherenkov detectors

    CERN Document Server

    Smale, N J

    2004-01-01

    A readout system for the Ring Imaging CHerenkov (RICH) detectors of the LHCb experiment has been developed. Two detector technologies for the measurement of Cherenkov photons are considered, the Multi-Anode Photo-Multiplier Tube (MAPMT) and the Hybrid Photon Detector (HPD), both of which meet the RICH requirements. The properties of the MAPMT are evaluated using a controlled single-photon source; a pixel-to-pixel gain variation of ~3 and a typical signal to noise of ~20 is measured. The relative tube efficiency is found to be reduced by ~26 % due to the detailed focusing structure of the MAPMT device. A radiation hard application-specific integrated circuit (ASIC) chip, the Beetle1.2MA0, has been developed to capture and store signals from a pair of MAPMTs. The Beetle1.2MA0 is built on the architecture of the Beetle family that was designed for silicon strip detectors, the difference being a modified front-end amplifier. The 128 input-channels of the Beetle1.2MA0 have a charge-sensitive pre-amplifier followed...

  18. Evolution of ground-based gamma-ray astronomy from the early days to the Cherenkov Telescope Arrays

    Science.gov (United States)

    Hillas, A. M.

    2013-03-01

    Most of what we know of cosmic gamma rays has come from spacecraft, but at energies above tens of GeV it has become possible to make observations with ground-based detectors of enormously greater collecting area. In recent years one such detector type, the cluster of imaging air Cherenkov telescopes, has reached a very productive state, whilst several alternative approaches have been explored, including converted solar power collectors and novel high-altitude particle shower detectors which promised to extend the energy range covered. Key examples of development from 1952 to 2011 are followed, noting the problems and discoveries that stimulated the current work, explaining the logic of the alternative approaches that were taken. The merits of the current major Cherenkov observatories and of other viable detectors are examined and compared, with examples of the astrophysical information they are beginning to provide. The detectors are still evolving, as we still do not understand the processes onto which the gamma rays provide a window. These include the acceleration of Galactic cosmic rays (in particular, the wide-band spectra of radiation from some individual supernova remnants are still hard to interpret), the highly relativistic and variable jets from active galactic nuclei, and aspects of the electrodynamics of pulsars. Larger groups of Cherenkov telescopes still offer the possibility of an increase in power of the technique for resolvable Galactic sources especially.

  19. Lunar imaging and ionospheric calibration for the Lunar Cherenkov technique

    NARCIS (Netherlands)

    McFadden, R.; Scholten, O.; Mevius, M.

    2013-01-01

    The Lunar Cherenkov technique is a promising method for UHE neutrino and cosmic ray detection which aims to detect nanosecond radio pulses produced during particle interactions in the Lunar regolith. For low frequency experiments, such as NuMoon, the frequency dependent dispersive effect of the iono

  20. The ARCADE Raman Lidar System for the Cherenkov Telescope Array

    CERN Document Server

    Valore, Laura; Doro, Michele; Iarlori, Marco; Rizi, Vincenzo; Tonachini, Aurelio Siro; Vallania, Piero

    2015-01-01

    The Cherenkov Telescope Array (CTA) is the next generation of ground-based very high energy gamma-ray instruments; the facility will be organized in two arrays, one for each hemisphere. The atmospheric calibration of the CTA telescopes is a critical task. The atmosphere affects the measured Cherenkov yield in several ways: the air-shower development itself, the variation of the Cherenkov angle with altitude, the loss of photons due to scattering and absorption of Cherenkov light out of the camera field-of-view and the scattering of photons into the camera. In this scenario, aerosols are the most variable atmospheric component in time and space and therefore need a continuous monitoring. Lidars are among the most used instruments in atmospheric physics to measure the aerosol attenuation profiles of light. The ARCADE Lidar system is a very compact and portable Raman Lidar system that has been built within the FIRB 2010 grant and is currently taking data in Lamar, Colorado. The ARCADE Lidar is proposed to operat...

  1. Large acceptance forward Cherenkov detector for the BRAHMS experiment at RHIC

    Energy Technology Data Exchange (ETDEWEB)

    Budick, B., E-mail: bb2@nyu.ed [New York University, New York, NY 10003 (United States); Beavis, D., E-mail: beavis@bnl.go [Brookhaven National Laboratory, Upton, NY 11973 (United States); Chasman, C., E-mail: chasman@bnl.go [Brookhaven National Laboratory, Upton, NY 11973 (United States)

    2010-09-21

    A multi-element detector based on Cherenkov radiation in plastic and on photomultiplier tubes has been constructed that is particularly useful in collider experiments. The detector covers the pseudorapidity interval 3.23<{eta}<5.25 with large acceptance for the products of proton-proton and heavy ion collisions. The detector's primary purposes are determining the vertex of the interaction, providing a minimum bias trigger, finding the start time for time of flight (and other timing applications), and monitoring the luminosity. Monte Carlo simulations describe the pulse height response of the detector well, as does an analytic expression that has been developed. The detector performed well in the RHIC experiment BRAHMS.

  2. Observation of Optical Flashes of the Night Star Sky on the Atmospheric Cherenkov Installation Tunka-13

    CERN Document Server

    Gress, O A; Pankov, L V; Parfenov, Y V; Semeney, Y A; Kuzmichev, L A; Parfenov, Yu. V.; Semeney, Yu. A.

    2000-01-01

    Experiment on the study of fluctuation of night glow is conducted on the base of 13 module atmospheric Cherenkov telescope TUNKA-13.Basic task of TUNKA-13 is registration of light from Extended Air Shower (EAS) initiated by primary cosmic particles. Observation of light flashes radiating in nigght atmosphere is one more experiment which is run for TUNKA-13 to study the background condition for EAS registration. At a period from December 1997 on a May 1998 was registered 149 light flashes of radiwting night atmosphere with duration from 16 ms to 190 seconds. General time of night observing has formed 237 hours. Coincidence of optical flashes with the gamma-bursts from the catalogue of BATSE experiment of observatories "Compton" was analysed.

  3. Experimental set-up of the LUNASKA lunar Cherenkov observations at the ATCA

    CERN Document Server

    James, C W; Philips, C J; Protheroe, R J; Roberts, P; Robinson, R A; Alvarez-Muñiz, J; Bray, J D

    2009-01-01

    This contribution describes the experimental set-up implemented by the LUNASKA project at the Australia Telescope Compact Array (ATCA) to enable the radio-telescope to be used to search for pulses of coherent Cherenkov radiation from UHE particle interactions in the Moon with an unprecedented bandwidth, and hence sensitivity. Our specialised hardware included analogue de-dispersion filters to coherently correct for the dispersion expected of a ~nanosecond pulse in the Earth's ionosphere over our wide (600 MHz) bandwidth, and FPGA-based digitising boards running at 2.048 GHz for pulse detection. The trigger algorithm is described, as are the methods used discriminate between terrestrial RFI and true lunar pulses. We also outline the next stage of hardware development expected to be used in our 2010 observations.

  4. Design and development of a Gadolinium-doped water Cherenkov detector

    Science.gov (United States)

    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

  5. On the "Non-Restricted special Relativity" theory (NRR), and further comments on "Cherenkov vs X-waves"

    OpenAIRE

    ZAMBONI-RACHED, MICHEL; Recami, Erasmo; Besieris, Ioannis M.

    2012-01-01

    Our aim in this paper is to recall some essential points of "Extended special Relativity", now more correctly called "Non-Restricted special Relativity" theory (NRR), and in particular of the extended Maxwell Equations; as well as to set forth some further comments on the basic differences between Cherenkov Radiation and the so-called X-shaped Waves, met within the more recent realm of the Non-diffracting Waves (also known as Localized Waves). The occasion is furnished by some very recent Ses...

  6. Stellar intensity interferometry: Optimizing air Cherenkov telescope array layouts

    CERN Document Server

    Jensen, Hannes; LeBohec, Stephan; Nuñez, Paul D; 10.1117/12.856412

    2010-01-01

    Kilometric-scale optical imagers seem feasible to realize by intensity interferometry, using telescopes primarily erected for measuring Cherenkov light induced by gamma rays. Planned arrays envision 50--100 telescopes, distributed over some 1--4 km$^2$. Although array layouts and telescope sizes will primarily be chosen for gamma-ray observations, also their interferometric performance may be optimized. Observations of stellar objects were numerically simulated for different array geometries, yielding signal-to-noise ratios for different Fourier components of the source images in the interferometric $(u,v)$-plane. Simulations were made for layouts actually proposed for future Cherenkov telescope arrays, and for subsets with only a fraction of the telescopes. All large arrays provide dense sampling of the $(u,v)$-plane due to the sheer number of telescopes, irrespective of their geographic orientation or stellar coordinates. However, for improved coverage of the $(u,v)$-plane and a wider variety of baselines (...

  7. An Analog Trigger System for Atmospheric Cherenkov Telescopes

    CERN Document Server

    Barcelo, M; Bigas, O Blanch; Boix, J; Delgado, C; Herranz, D; Lopez-Coto, R; Martinez, G

    2013-01-01

    Arrays of Cherenkov telescopes typically use multi-level trigger schemes to keep the rate of random triggers from the night sky background low. At a first stage, individual telescopes produce a trigger signal from the pixel information in the telescope camera. The final event trigger is then formed by combining trigger signals from several telescopes. In this poster, we present a possible scheme for the Cherenkov Telescope Array telescope trigger, which is based on the analog pulse information of the pixels in a telescope camera. Advanced versions of all components of the system have been produced and working prototypes have been tested, showing a performance that meets the original specifications. Finally, issues related to integrating the trigger system in a telescope camera and in the whole array will be dealt with.

  8. Normalized and Asynchronous Mirror Alignment for Cherenkov Telescopes

    CERN Document Server

    Ahnen, M L; 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

    2016-01-01

    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 ca...

  9. G-APDs in Cherenkov astronomy: The FACT camera

    Energy Technology Data Exchange (ETDEWEB)

    Kraehenbuehl, T., E-mail: thomas.kraehenbuehl@phys.ethz.ch [ETH Zurich, Institute for Particle Physics, CH-8093 Zurich (Switzerland); Anderhub, H. [ETH Zurich, Institute for Particle Physics, CH-8093 Zurich (Switzerland); Backes, M. [Technische Universitaet Dortmund, D-44221 Dortmund (Germany); Biland, A.; Boller, A.; Braun, I. [ETH Zurich, Institute for Particle Physics, CH-8093 Zurich (Switzerland); Bretz, T. [Ecole Polytechnique Federale de Lausanne, CH-1015 Lausanne (Switzerland); Commichau, V.; Djambazov, L. [ETH Zurich, Institute for Particle Physics, CH-8093 Zurich (Switzerland); Dorner, D.; Farnier, C. [ISDC Data Center for Astrophysics, CH-1290 Versoix (Switzerland); Gendotti, A.; Grimm, O.; Gunten, H. von; Hildebrand, D.; Horisberger, U.; Huber, B.; Kim, K.-S. [ETH Zurich, Institute for Particle Physics, CH-8093 Zurich (Switzerland); Koehne, J.-H.; Krumm, B. [Technische Universitaet Dortmund, D-44221 Dortmund (Germany); and others

    2012-12-11

    Geiger-mode avalanche photodiodes (G-APD, SiPM) are a much discussed alternative to photomultiplier tubes in Cherenkov astronomy. The First G-APD Cherenkov Telescope (FACT) collaboration builds a camera based on a hexagonal array of 1440 G-APDs and has now finalized its construction phase. A light-collecting solid PMMA cone is glued to each G-APD to eliminate dead space between the G-APDs by increasing the active area, and to restrict the light collection angle of the sensor to the reflector area in order to reduce the amount of background light. The processing of the signals is integrated in the camera and includes the digitization using the domino ring sampling chip DRS4.

  10. Cherenkov loss factor of short relativistic bunches:general approach

    CERN Document Server

    Baturin, S S

    2013-01-01

    The interaction of short relativistic charged particle bunches with waveguides and other accelerator system components is a critical issue for the development of X-ray FELs (free electron lasers) and linear collider projects. Wakefield Cherenkov losses of short bunches have been studied previously for resistive wall, disk-loaded, corrugated and dielectric loaded waveguides. It was noted in various publications [1] that if the slowdown layer is thin, the Cherenkov loss factor of a short bunch does not depend on the guiding system material and is a constant for any given transverse cross section dimensions of the waveguides. In this paper, we consider a new approach to the analysis of loss factors for relativistic short bunches and formulate a general integral relation that allows calculation of the loss factor for a short relativistic bunch passing an arbitrary waveguide system. The loss factors calculated by this new method for various types of waveguides with arbitrary thickness slowdown layers, including in...

  11. Gas breakdown limits for inverse Cherenkov laser accelerators

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y. [California Univ., Los Angeles, CA (United States). Dept. of Physics; Pogorelsky, I.V. [Brookhaven National Lab., Upton, NY (United States)

    1995-07-01

    The probability of avalanche, tunneling and multiphoton ionization induced by a CO{sub 2} laser in H{sub 2} gas has been calculated. Laser light screening by a self-induced plasma density gradient is considered as the limiting factor for upscaling a CO{sub 2} laser-driven Inverse Cherenkov Laser Accelerator beyond 650 MeV/m. However, in near-resonance inverse Cherenkov acceleration where a shorter wavelength laser is used at a wavelength near the resonance of the gas (e.g. 248nm in H{sub 2}), the formation of a plasma is not a problem because the plasma density is below the critical density. In that case, the laser beam propagates unaffected through the plasma and the acceleration gradient is not limited by gas breakdown. Gradients > 1 GeV/m are possible.

  12. Design of light concentrators for Cherenkov telescope observatories

    CERN Document Server

    Hénault, F; jocou, L; Khélifi, B; Manigot, P; Hormigos, S; Knodlseder, J; Olive, J F; Jean, P; Punch, M

    2013-01-01

    The Cherenkov Telescope Array (CTA) will be the largest cosmic gamma ray detector ever built in the world. It will be installed at two different sites in the North and South hemispheres and should be operational for about 30 years. In order to cover the desired energy range, the CTA is composed of typically 50-100 collecting telescopes of various sizes (from 6 to 24-m diameters). Most of them are equipped with a focal plane camera consisting of 1500 to 2000 Photomultipliers (PM) equipped with light concentrating optics, whose double function is to maximize the amount of Cherenkov light detected by the photo-sensors, and to block any stray light originating from the terrestrial environment. Two different optical solutions have been designed, respectively based on a Compound Parabolic Concentrator (CPC), and on a purely dioptric concentrating lens. In this communication are described the technical specifications, optical designs and performance of the different solutions envisioned for all these light concentra...

  13. A quartz Cherenkov detector for polarimetry at the ILC

    International Nuclear Information System (INIS)

    At the proposed International Linear Collider (ILC), the use of polarised electron and positron beams is a key ingredient of the physics program. A measurement of the polarisation with a yet unprecedented precision of δP/P=0.25% is required. To achieve this, Compton polarimeter measurements in front of and behind the collision point are foreseen. In this thesis, a novel concept for a detector for ILC polarimetry is introduced to eliminate one of the dominating systematics limiting the previous best measurement of beam polarisation: a detector using quartz as Cherenkov medium could increase the tolerance against non-linear photodetector responses. The high refractive index of quartz results in a higher Cherenkov light yield compared to conventional Cherenkov gases. This could allow single-peak resolution in the Cherenkov photon spectra produced by the Compton electrons at the polarimeters. The detailed simulation studies presented in this work imply that such single-peak resolution is possible. Considerations for the choice of a suitable detector geometry are discussed. A four-channel prototype has been constructed and successfully operated in a first testbeam campaign at the DESY testbeam, confirming simulation predictions. Although further studies have to be considered to quantify all aspects of the detector response, the findings of the analysis of the data from the first testbeam are promising with regards to reaching the desired light yield. In the final part of this thesis, the application of a detector concept allowing single-peak resolution to the polarisation measurement at the ILC is examined. Two of the main sources of systematic uncertainties on the polarimeter measurements are detector non-linearities and misalignments. The performance of the suggested quartz detector concept in Monte Carlo studies promises a control of these systematics which meets the precision requirements for ILC polarimetry.

  14. An Innovative Workspace for The Cherenkov Telescope Array

    OpenAIRE

    Costa, Alessandro; Sciacca, Eva; Becciani, Ugo; Massimino, Piero; Riggi, Simone; Sanchez, David; Vitello, Fabio

    2016-01-01

    The Cherenkov Telescope Array (CTA) is an initiative to build the next generation, ground-based gamma-ray observatories. We present a prototype workspace developed at INAF that aims at providing innovative solutions for the CTA community. The workspace leverages open source technologies providing web access to a set of tools widely used by the CTA community. Two different user interaction models, connected to an authentication and authorization infrastructure, have been implemented in this wo...

  15. Single domain wall effect on parametric processes via Cherenkov-type phase matching

    OpenAIRE

    Deng, Xuewei; Ren, Huaijin; Zheng, Yuanlin; Chen, Xianfeng

    2010-01-01

    We report on important influence of single domain wall (DW) of electrically poled ferroelectric crystal on parametric processes via Cherenkov-type phase matching. It shows that the effective nonlinear polarization is confined in DW and its phase velocity can be modulated when incident light is off domain wall's direction. These effects lead to novel Cherenkov second harmonic generation (CSHG) which has no analogue in bulk ferroelectrics. Complex DW-modulated parametric process via Cherenkov-t...

  16. Normalized and asynchronous mirror alignment for Cherenkov telescopes

    Science.gov (United States)

    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).

  17. Photo multiplier tubes candidates for the Cherenkov telescope array project

    International Nuclear Information System (INIS)

    Photo Multiplier Tubes (PMTs) are the most wide spread detectors for fast low-level light signals. They are commonly used as standard light sensors for camera systems in imaging atmospheric Cherenkov telescopes. Years ago, an improvement program for the PMT candidates for the Cherenkov Telescope Array (CTA) project was initialized with the companies Hamamatsu Photonics K.K. (Japan) and Electron Tubes Enterprises Ltd. (England). CTA is the next generation of imaging atmospheric Cherenkov telescopes for high energy gamma ray astrophysics. Therefore, we need PMTs with outstanding good parameters concerning quantum efficiency, pulse width, after-pulsing and transit time spread. The currently available ''super-bialkali'' PMTs show a peak Quantum Efficiency of 40% and have an enhanced collection efficiency of up to 95-98% for wavelengths≥400 nm. The pulse width averages around 3ns at a gain of 40000. Also, the after-pulsing for a set threshold level of ≥4 photo electrons is reduced down to 0,02%. We report on the measurement results of PMT R-12292-100 from Hamamatsu as the final version and the intermediate version PMT D569/3SA from Electron Tubes Enterprises as candidate PMTs for the CTA project.

  18. Detection of tau neutrinos by Imaging Air Cherenkov Telescopes

    CERN Document Server

    Gora, Dariusz

    2015-01-01

    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 analysed 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 Cherenk...

  19. FACT -- Operation of the First G-APD Cherenkov Telescope

    CERN Document Server

    Bretz, T; Buß, J; Commichau, V; Djambazov, L; Dorner, D; Einecke, S; Eisenacher, D; Freiwald, J; Grimm, O; von Gunten, H; Haller, C; Hempfling, C; Hildebrand, D; Hughes, G; Horisberger, U; Knoetig, M L; Krähenbühl, T; Lustermann, W; Lyard, E; Mannheim, K; Meier, K; Mueller, S; Neise, D; Overkemping, A -K; Paravac, A; Pauss, F; Rhode, W; Röser, U; Stucki, J -P; Steinbring, T; Temme, F; Thaele, J; Vogler, P; Walter, R; Weitzel, Q

    2014-01-01

    Since more than two years, the First G-APD Cherenkov Telescope (FACT) is operating successfully at the Canary Island of La Palma. Apart from its purpose to serve as a monitoring facility for the brightest TeV blazars, it was built as a major step to establish solid state photon counters as detectors in Cherenkov astronomy. The camera of the First G-APD Cherenkov Telesope comprises 1440 Geiger-mode avalanche photo diodes (G-APD aka. MPPC or SiPM) for photon detection. Since properties as the gain of G-APDs depend on temperature and the applied voltage, a real-time feedback system has been developed and implemented. To correct for the change introduced by temperature, several sensors have been placed close to the photon detectors. Their read out is used to calculate a corresponding voltage offset. In addition to temperature changes, changing current introduces a voltage drop in the supporting resistor network. To correct changes in the voltage drop introduced by varying photon flux from the night-sky background...

  20. PyFACT: Python and FITS analysis for Cherenkov telescopes

    Science.gov (United States)

    Raue, Martin; Deil, Christoph

    2012-12-01

    Ground-based very-high energy (VHE; E>100 GeV) gamma-ray astronomy is growing from being conducted by small teams in closed collaborations into a full-fledged branch of astronomy with open observatories. This is best illustrated by the number of known sources: it increased by one order of magnitude in the past ten years, from 10 in the year 2000 to more than 100 in 2010. It is expected that this trend will continue with the next-generation instrument Cherenkov Telescope Array (CTA). This transformation has a profound impact on the data format and analysis of Imaging Atmospheric Cherenkov Telescopes (IACTs). Up to now, IACT data analysis was an internal task performed by specialists with no public access to the data or software. In the future, a large community of VHE astronomers from different scientific topics should be enabled to work with the data. Ease of use, compatibility, and integration with existing astronomy standards and tools will be key. In this contribution, a collection of Python tools for the analysis of data in FITS format (PyFACT; Python and FITS Analysis for Cherenkov Telescopes) is presented, which connects with existing tools like xspec, sherpa, and ds9. The package is available as open source (https://github.com/mraue/pyfact, comments and contributions welcome). Advantages of the chosen ansatz are discussed and implications for future observatories and data archival are presented.

  1. Detection of tau neutrinos by Imaging Air Cherenkov Telescopes

    CERN Document Server

    Gora, Dariusz

    2016-01-01

    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 Cherenk...

  2. Experimental study and Monte Carlo modeling of the Cherenkov effect

    Energy Technology Data Exchange (ETDEWEB)

    Mishev, A.; Angelov, I.; Duverger, E.; Gschwind, R.; Makovicka, L. E-mail: libor.makovicka@pu-pm.univ-fcomte.fr; Stamenov, J

    2001-12-01

    Studies realised at the Institute for Nuclear Research and Nuclear Energy (INRNE) particularly in cosmic ray detection and construction of Muonic Cherenkov Telescope at the South West University 'Neofit Rilski' Blagoevgrad show the need to develop a theoretical model based on observed phenomena and to refinement of this for detection system optimisation. The Cherenkov effect was introduced in EGS4 code system. The first simulations realised in collaboration between the french and the bulgarian team were consecrated to different geometries of water tank in total reflection. An additional modeling of photons mean trajectory and the mean number of reflections in the tank were made. This simple model was compared with experimental data realised with {sup 60}Co gamma source, the telescope and the most efficient water tank. A trajectory simulation of Cherenkov photons in water tank was made. An efficiency estimation of the detector registration was calculated. The atmospheric model was introduced in EGS4 code and a comparison between CORSIKA5.62 and EGS4 codes was made.

  3. Novel Photo Multiplier Tubes for the Cherenkov Telescope Array Project

    CERN Document Server

    Toyama, Takeshi; Dickinson, Hugh; Fruck, Christian; Hose, Jürgen; Kellermann, Hanna; Knötig, Max; Lorenz, Eckart; Menzel, Uta; Nakajima, Daisuke; Orito, Reiko; Paneque, David; Schweizer, Thomas; Teshima, Masahiro; Yamamoto, Tokonatsu

    2013-01-01

    Currently the standard light sensors for imaging atmospheric Cherenkov telescopes are the classical photo multiplier tubes that are using bialkali photo cathodes. About eight years ago we initiated an improvement program with the Photo Multiplier Tube (PMT) manufacturers Hamamatsu (Japan), Electron Tubes Enterprises (England) and Photonis (France) for the needs of imaging atmospheric Cherenkov telescopes. As a result, after about 40 years of stagnation of the peak Quantum Efficiency (QE) on the level of 25-27%, new PMTs appeared with a peak QE of 35%. These have got the name super-bialkali. The second significant upgrade has happened very recently, as a result of a dedicated improvement program for the candidate PMT for Cherenkov Telescope Array. The latter is going to be the next generation major instrument in the field of very high energy gamma astrophysics and will consist of over 100 telescopes of three different sizes of 23m, 12m and 4-7m, located both in southern and northern hemispheres. Now PMTs with ...

  4. Soft x-ray generation by the Cherenkov effect

    Energy Technology Data Exchange (ETDEWEB)

    Moran, M.J.; Chang, B.

    1987-01-01

    The Cherenkov effect may be used to generate coherent soft x rays by taking advantage of the dielectric constants of materials in the neighborhood of atomic resonances. The Cherenkov effect usually is not possible for x rays because the refractive index is less than one for most x-ray frequencies. However, for narrow frequency bands near atomic resonances, the refractive index can exceed unity with values large enough to generate coherent x rays with efficiencies higher than any other electron-driven technique. The basic physics of the process is discussed and is used to make rough estimates of photon production efficiencies. An exact theoretical description of Cherenkov production in thin foils is used together with recently-measured refractive indices to calculate the emission distributions of 100 eV photons from thin silicon foils. These distributions are found to be roughly consistent with the simple estimates. In addition, unusual behavior by the distributions suggests a technique that can be used to increase dramatically the peak angular intensities.

  5. Soft x-ray generation by the Cherenkov effect

    International Nuclear Information System (INIS)

    The Cherenkov effect may be used to generate coherent soft x rays by taking advantage of the dielectric constants of materials in the neighborhood of atomic resonances. The Cherenkov effect usually is not possible for x rays because the refractive index is less than one for most x-ray frequencies. However, for narrow frequency bands near atomic resonances, the refractive index can exceed unity with values large enough to generate coherent x rays with efficiencies higher than any other electron-driven technique. The basic physics of the process is discussed and is used to make rough estimates of photon production efficiencies. An exact theoretical description of Cherenkov production in thin foils is used together with recently-measured refractive indices to calculate the emission distributions of 100 eV photons from thin silicon foils. These distributions are found to be roughly consistent with the simple estimates. In addition, unusual behavior by the distributions suggests a technique that can be used to increase dramatically the peak angular intensities. 15 refs., 10 figs

  6. Soft x-ray generation by the Cherenkov effect

    International Nuclear Information System (INIS)

    The Cherenkov effect may be used to generate coherent soft x rays by taking advantage of the dielectric constants of materials in the neighborhood of atomic resonances. The Cherenkov effect usually is not possible for x rays because the refractive index is less than one for most x-ray frequencies. However, for narrow frequency bands near atomic resonances, the refractive index can exceed unity with values large enough to generate coherent x rays with efficiencies higher than any other electron-driven technique. The basic physics of the process is discussed and is used to make rough estimates of photon production efficiencies. An exact theoretical description of Cherenkov production in thin foils is used together with recently-measured refractive indices to calculate the emission distributions of 100 eV photons from thin silicon foils. These distributions are found to be roughly consistent with the simple estimates. In addition, unusual behavior by the distributions suggests a technique that can be used to increase dramatically the peak angular intensities

  7. Soft x-ray generation by the Cherenkov effect

    Energy Technology Data Exchange (ETDEWEB)

    Moran, M.J.; Chang, B.

    1987-02-25

    The Cherenkov effect may be used to generate coherent soft x rays by taking advantage of the dielectric constants of materials in the neighborhood of atomic resonances. The Cherenkov effect usually is not possible for x rays because the refractive index is less than one for most x-ray frequencies. However, for narrow frequency bands near atomic resonances, the refractive index can exceed unity with values large enough to generate coherent x rays with efficiencies higher than any other electron-driven technique. The basic physics of the process is discussed and is used to make rough estimates of photon production efficiencies. An exact theoretical description of Cherenkov production in thin foils is used together with recently-measured refractive indices to calculate the emission distributions of 100 eV photons from thin silicon foils. These distributions are found to be roughly consistent with the simple estimates. In addition, unusual behavior by the distributions suggests a technique that can be used to increase dramatically the peak angular intensities. 15 refs., 10 figs.

  8. Development of a SiPM Camera for a Schwarzschild-Couder Cherenkov Telescope for the Cherenkov Telescope Array

    CERN Document Server

    Otte, A N; Dickinson, H.; Funk, S.; Jogler, T.; Johnson, C.A.; Karn, P.; Meagher, K.; Naoya, H.; Nguyen, T.; Okumura, A.; Santander, M.; Sapozhnikov, L.; Stier, A.; Tajima, H.; Tibaldo, L.; Vandenbroucke, J.; Wakely, S.; Weinstein, A.; Williams, D.A.

    2015-01-01

    We present the development of a novel 11328 pixel silicon photomultiplier (SiPM) camera for use with a ground-based Cherenkov telescope with Schwarzschild-Couder optics as a possible medium-sized telescope for the Cherenkov Telescope Array (CTA). The finely pixelated camera samples air-shower images with more than twice the optical resolution of cameras that are used in current Cherenkov telescopes. Advantages of the higher resolution will be a better event reconstruction yielding improved background suppression and angular resolution of the reconstructed gamma-ray events, which is crucial in morphology studies of, for example, Galactic particle accelerators and the search for gamma-ray halos around extragalactic sources. Packing such a large number of pixels into an area of only half a square meter and having a fast readout directly attached to the back of the sensors is a challenging task. For the prototype camera development, SiPMs from Hamamatsu with through silicon via (TSV) technology are used. We give ...

  9. Possible usage of Cherenkov photons to reduce the background in a 136Xe neutrino-less double-beta decay experiment

    Science.gov (United States)

    Signorelli, G.; Dussoni, S.

    2016-07-01

    One of the main backgrounds in the search for 136Xe nutrino-less double-beta decay (0 νββ) is the signal from Compton scattering of photons with energy around the decay endpoint at 2.458 MeV. Electrons in liquid xenon emit scintillation light at 178 nm. Liquid xenon being extremely transparent to ultra violet light it is in principle possible to discriminate one particle events (such as the Compton background) from two particle events (double-beta decay signals) by the amount of Cherenkov radiation emitted. The identification of the Cherenkov photons may be performed by looking at the different time structure of the signal with respect to the scintillation, by selecting photons with wavelengths larger than the typical Xenon scintillation light, and by the different emission topology. A proof-of-principle study of this approach is presented here together with preliminary studies on possible detectors for the two light components at different wavelengths.

  10. CHERENCUBE: Concept definition and implementation challenges of a Cherenkov-based detector block for PET

    International Nuclear Information System (INIS)

    Purpose: A new concept for a depth-of-interaction (DOI) capable time-of-flight (TOF) PET detector is defined, based only on the detection of Cherenkov photons. The proposed “CHERENCUBE” consists of a cubic Cherenkov radiator with position-sensitive photodetectors covering each crystal face. By means of the spatial distribution of the detected photons and their time of arrival, the point of interaction of the gamma-ray in the crystal can be determined. This study analyzes through theoretical calculations and Monte Carlo simulations the potential advantages of the concept toward reaching a Cherenkov-only detector for TOF-PET with DOI capability. Furthermore, an algorithm for the DOI estimation is presented and the requirements for a practical implementation of the proposed concept are defined. Methods: The Monte Carlo simulations consisted of a cubic crystal with one photodetector coupled to each one of the faces of the cube. The sensitive area of the detector matched exactly the crystal size, which was varied in 1 mm steps between 1 × 1 × 1 mm3 and 10 × 10 × 10 mm3. For each size, five independent simulations of ten thousand 511 keV gamma-rays were triggered at a fixed distance of 10 mm. The crystal chosen was PbWO4. Its scintillation properties were simulated, but only Cherenkov photons were analyzed. Photodetectors were simulated having perfect photodetection efficiency and infinite time resolution. For every generated particle, the analysis considered its creation process, parent and daughter particles, energy, origin coordinates, trajectory, and time and position of detection. The DOI determination is based on the distribution of the emission time of all photons per event. These values are calculated as a function of the coordinates of detection and origin for every photon. The common origin is estimated by finding the distribution with the most similar emission time-points. Results: Detection efficiency increases with crystal size from 8.2% (1 × 1 × 1

  11. The Cherenkov Surface Detector of the Pierre Auger Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Billoir, Pierre, E-mail: billoir@lpnhe.in2p3.fr [LPNHE, CNRS/IN2P3 and Univ. P. and M. Curie and Univ. D. Diderot, 4 place Jussieu 75272 Paris Cedex 05 (France); Observatorio Pierre Auger, av. San Martín Norte, 304 5613, Malargüe (Argentina)

    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 km{sup 2}), 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. - Highlights: • The water Cherenkov technique is used in the Surface Detector of the Pierre Auger Observatory. • Cross-calibrated with the Fluorescence Detector, it provides a measurement of the primary energy. • The spectrum of the UHE cosmic rays exhibits clearly an “ankle” and a cutoff. • The muon observed muon content of the atmospheric showers is larger than expected from the models. • Stringent limits on the flux of UHE neutrinos and photons are obtained.

  12. MEMPHYS: A large scale water Cherenkov detector at Frejus

    Energy Technology Data Exchange (ETDEWEB)

    Bellefon, A. de; Dolbeau, J.; Gorodetzky, P.; Katsanevas, S.; Patzak, T.; Salin, P.; Tonazzo, A. [APC Paris, Paris (France); Bouchez, J. [APC Paris, Paris (France)]|[DAPNIA-CEA Saclay (France); Busto, J. [CPP Marseille (France); Campagne, J.E. [LAL Orsay (France); Cavata, C.; Mosca, L. [DAPNIA-CEA Saclay (France); Dumarchez, J. [LPNHE Paris (France); Mezzetto, M. [INFN Padova (Italy); Volpe, C. [IPN Orsay (France)

    2006-07-15

    A water Cherenkov detector project, of megaton scale, to be installed in the Frejus underground site and dedicated to nucleon decay, neutrinos from supernovae, solar and atmospheric neutrinos, as well as neutrinos from a super-beam and/or a beta-beam coming from CERN, is presented and compared with competitor projects in Japan and in the USA. The performances of the European project are discussed, including the possibility to measure the mixing angle {theta}{sub 13} and the CP-violating phase {delta}. (authors)

  13. Measurements and simulations of Cherenkov light in lead fluoride crystals

    OpenAIRE

    P. Achenbach(Mainz U., Inst. Phys); Baunack, S.; Grimm, K.; Hammel, T.; von Harrach, D.,; Ginja, A. Lopes; Maas, F. E.; Schilling, E.; Stroeher, H.

    2001-01-01

    The anticipated use of more than one thousand lead fluoride (PbF2) crystals as a fast and compact Cherenkov calorimeter material in a parity violation experiment at MAMI stimulated the investigation of the light yield (L.Y.) of these crystals. The number of photoelectrons (p.e.) per MeV deposited energy has been determined with a hybrid photomultiplier tube (HPMT). In response to radioactive sources a L.Y. between 1.7 and 1.9 p.e./MeV was measured with 4% statistical and 5% systematic error. ...

  14. Towards a network of atmospheric Cherenkov detectors 7

    Energy Technology Data Exchange (ETDEWEB)

    Robin, M. [Ecole Polytechnique, 91 - Palaiseau (France); Weekes, T.C. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Mori, M. [Tokyo Univ., Institute for Cosmic Ray Research (Japan); Mariotti, M. [Padova Univ., INFN (Italy); Hofmann, W.; Aharonian, F. [Max-Planck-Institut fuer Kernphysik, Heidelberg (Germany); Sinitsyna, V. [P.N. Lebedev Physical Institute, Moscow (Russian Federation); Smith, D. [Centre d' Etudes Nucleaires de Bordeaux Gradignan, 33 - Gradignan (France); Marleau, P. [California Univ., Davis, CA (United States); Sinnis, G. [Los Alamos National Lab., NM (United States); Volk, H. [Max-Planck-Institut fur Kernphysik (Germany); Jager, O. de [South Africa Univ., North-West (South Africa); Harding, A. [NASA Goddard Space Flight Center (United States); Coppi, P. [Yale Univ., New Haven, CT (United States); Dermer, C. [Naval Research Laboratory (United States); Goldwurm, A.; Paul, J. [CEA Saclay, Dept. d' Astrophysique, de Physique des Particules de Physique Nucleaire et de l' Instrumentation Associee, 91- Gif sur Yvette (France); Puhlhofer, G. [Landessternwarte Heidelberg (Germany); Bernardini, E. [DESy-Zeuthen (Germany); Swordy, S. [Chicago Univ., IL (United States); Yoshikoshi, T. [Tokyo Univ., Tanashi (Japan). Inst. for Cosmic Ray Research; Teshima, M. [Max-Planck-Institute for Physics, Munich (Germany); Punch, M. [Astrophysique et Cosmologie (APC), College de France, 75 - Paris (France)

    2005-07-01

    This document gathers the papers and transparencies presented at the conference. The main part of the conference was organized into 6 sessions: 1) the review of present experiments (Veritas, Cangaroo-3, Magic, Hess-1, Shalon, Cactus, Cygnus-X-3...), 2) calibration and analysis techniques in VHE (very high energy) astrophysics, 3) multi-wavelength observations and phenomenology of sources, 4) the future of ground-based VHE astronomy, 5) developments in instrumentation for Cherenkov telescopes, and 6) the evolution of the field and its link with mainstream astrophysics.

  15. CELESTE an atmospheric Cherenkov telescope for high energy gamma astrophysics

    CERN Document Server

    Paré, E; Bazer-Bachi, R; Bergeret, H; Berny, F; Briand, N; Bruel, P; Cerutti, M; Collon, J; Cordier, A; Cornebise, P; Debiais, G; Dezalay, J P; Dumora, D; Durand, E; Eschstruth, P T; Espigat, P; Fabre, B; Fleury, P; Gilly, J; Gouillaud, J C; Gregory, C; Herault, N; Holder, J; Hrabovsky, M; Incerti, S; Jouenne, A; Kalt, L; Legallou, R; Lott, B; Lodygensky, O; Manigot, P; Manseri, H; Manitaz, H; Martin, M; Morano, R; Morineaud, G; Muenz, F; Musquere, A; Naurois, M D; Neveu, J; Noppe, J M; Olive, J F; Palatka, M; Pérez, A; Quebert, J; Rebii, A; Reposeur, T; Rob, L; Roy, P; Sans, J L; Sako, T; Schovanek, P; Smith, D A; Snabre, P; Villard, G

    2002-01-01

    CELESTE is an atmospheric Cherenkov telescope based on the sampling method which makes use of the de-commissioned THEMIS solar electrical plant in the French Pyrenees. A large (2000 m sup 2) mirror surface area from 40 independent heliostats followed by a secondary optic, a trigger system using analog summing techniques and signal digitization with 1 GHz flash ADCs make possible the detection of cosmic gamma-rays down to 30 GeV. This paper provides a detailed technical description of the CELESTE installation.

  16. Development of the Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE)

    CERN Document Server

    Ong, R A

    1998-01-01

    STACEE is a proposed atmospheric Cherenkov telescope for ground-based gamma-ray astrophysics between 25 and 500 GeV. The telescope will make use of the large solar mirrors (heliostats) available at a solar research facility to achieve an energy threshold lower than any existing ground-based instrument. This paper describes the development of STACEE, including an overview of the complete instrument design and a discussion of results from recent prototype tests at the large solar heliostat field of Sandia National Laboratories.

  17. Control Software for the VERITAS Cherenkov Telescope System

    CERN Document Server

    Krawczynski, H; Sembroski, G; Gibbs, K

    2003-01-01

    The VERITAS collaboration is developing a system of initially 4 and eventually 7 Cherenkov Telescopes of the 12 m diameter class for high sensitivity gamma-ray astronomy in the >50 GeV energy range. In this contribution we describe the software that controls and monitors the various VERITAS sub-systems. The software uses an object-oriented approach to cope with the complexities that arise from using sub-groups of the 7 VERITAS telescopes to observe several sources at the same time. Inter-process communication is based on the CORBA Object Request Broker protocol and watch-dog processes monitor the sub-system performance.

  18. The Ring Imaging Cherenkov detector of the AMS experiment: test beam results with a prototype

    CERN Document Server

    Arruda, Luísa; Goncalves, Patrícia; Pereira, Rui

    2008-01-01

    The Alpha Magnetic Spectrometer (AMS) to be installed on the International Space Station (ISS) will be equipped with a proximity Ring Imaging Cherenkov (RICH) detector for measuring the velocity and electric charge of the charged cosmic particles. This detector will contribute to the high level of redundancy required for AMS as well as to the rejection of albedo particles. Charge separation up to iron and a velocity resolution of the order of 0.1% for singly charged particles are expected. A RICH protoptype consisting of a detection matrix with 96 photomultiplier units, a segment of a conical mirror and samples of the radiator materials was built and its performance was evaluated. Results from the last test beam performed with ion fragments resulting from the collision of a 158 GeV/c/nucleon primary beam of indium ions (CERN SPS) on a lead target are reported. The large amount of collected data allowed to test and characterize different aerogel samples and the sodium fluoride radiator. In addition, the reflec...

  19. Tests of innovative photon detectors and integrated electronics for the large-area CLAS12 ring-imaging Cherenkov detector

    Energy Technology Data Exchange (ETDEWEB)

    Contalbrigo, Marco [INFN, Ferrara, Italy

    2015-07-01

    A large area ring-imaging Cherenkov detector has been designed to provide clean hadron identification capability in the momentum range from 3 GeV/c to 8 GeV/c for the CLAS12 experiments at the upgraded 12 GeV continuous electron beam accelerator facility of Jefferson Lab. Its aim is to study the 3D nucleon structure in the yet poorly explored valence region by deep-inelastic scattering, and to perform precision measurements in hadron spectroscopy. The adopted solution foresees a novel hybrid optics design based on an aerogel radiator, composite mirrors and a densely packed and highly segmented photon detector. Cherenkov light will either be imaged directly (forward tracks) or after two mirror reflections (large angle tracks). Extensive tests have been performed on Hamamatsu H8500 and novel flat multi-anode photomultipliers under development and on various types of silicon photomultipliers. A large scale prototype based on 28 H8500 MA-PMTs has been realized and tested with few GeV/c hadron beams at the T9 test-beam facility of CERN. In addition a small prototype was used to study the response of customized SiPM matrices within a temperature interval ranging from 25 down to –25 °C. The preliminary results of the individual photon detector tests and of the prototype performance at the test-beams are here reported.

  20. Tests of innovative photon detectors and integrated electronics for the large-area CLAS12 ring-imaging Cherenkov detector

    Energy Technology Data Exchange (ETDEWEB)

    Contalbrigo, M., E-mail: contalbrigo@fe.infn.it

    2015-07-01

    A large area ring-imaging Cherenkov detector has been designed to provide clean hadron identification capability in the momentum range from 3 GeV/c to 8 GeV/c for the CLAS12 experiments at the upgraded 12 GeV continuous electron beam accelerator facility of Jefferson Lab. Its aim is to study the 3D nucleon structure in the yet poorly explored valence region by deep-inelastic scattering, and to perform precision measurements in hadron spectroscopy. The adopted solution foresees a novel hybrid optics design based on an aerogel radiator, composite mirrors and a densely packed and highly segmented photon detector. Cherenkov light will either be imaged directly (forward tracks) or after two mirror reflections (large angle tracks). Extensive tests have been performed on Hamamatsu H8500 and novel flat multi-anode photomultipliers under development and on various types of silicon photomultipliers. A large scale prototype based on 28 H8500 MA-PMTs has been realized and tested with few GeV/c hadron beams at the T9 test-beam facility of CERN. In addition a small prototype was used to study the response of customized SiPM matrices within a temperature interval ranging from 25 down to −25 °C. The preliminary results of the individual photon detector tests and of the prototype performance at the test-beams are here reported.

  1. The Cherenkov Surface Detector of the Pierre Auger Observatory

    Science.gov (United States)

    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.

  2. Highlights from the High Altitude Water Cherenkov Observatory

    CERN Document Server

    Pretz, John

    2015-01-01

    The High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory was completed this year at a 4100-meter site on the flank of the Sierra Negra volcano in Mexico. HAWC is a water Cherenkov ground array with the capability to distinguish 100 GeV - 100 TeV gamma rays from the hadronic cosmic-ray background. HAWC is uniquely suited to study extremely high energy cosmic-ray sources, search for regions of extended gamma-ray emission, and to identify transient gamma-ray phenomena. HAWC will play a key role in triggering multi-wavelength and multi-messenger studies of active galaxies, gamma-ray bursts, supernova remnants and pulsar wind nebulae. Observation of TeV photons also provide unique tests for a number of fundamental physics phenomena including dark matter annihilation and primordial black hole evaporation. Operation began mid-2013 with the partially-completed detector. Multi-TeV emission from the Galactic Plane is clearly seen in the first year of operation, confirming a number of known TeV sources, and a numb...

  3. INFN Camera demonstrator for the Cherenkov Telescope Array

    CERN Document Server

    Ambrosi, G; Aramo, C.; Bertucci, B.; Bissaldi, E.; Bitossi, M.; Brasolin, S.; Busetto, G.; Carosi, R.; Catalanotti, S.; Ciocci, M.A.; Consoletti, R.; Da Vela, P.; Dazzi, F.; De Angelis, A.; De Lotto, B.; de Palma, F.; Desiante, R.; Di Girolamo, T.; Di Giulio, C.; Doro, M.; D'Urso, D.; Ferraro, G.; Ferrarotto, F.; Gargano, F.; Giglietto, N.; Giordano, F.; Giraudo, G.; Iacovacci, M.; Ionica, M.; Iori, M.; Longo, F.; Mariotti, M.; Mastroianni, S.; Minuti, M.; Morselli, A.; Paoletti, R.; Pauletta, G.; Rando, R.; Fernandez, G. Rodriguez; Rugliancich, A.; Simone, D.; Stella, C.; Tonachini, A.; Vallania, P.; Valore, L.; Vagelli, V.; Verzi, V.; Vigorito, C.

    2015-01-01

    The Cherenkov Telescope Array is a world-wide project for a new generation of ground-based Cherenkov telescopes of the Imaging class with the aim of exploring the highest energy region of the electromagnetic spectrum. With two planned arrays, one for each hemisphere, it will guarantee a good sky coverage in the energy range from a few tens of GeV to hundreds of TeV, with improved angular resolution and a sensitivity in the TeV energy region better by one order of magnitude than the currently operating arrays. In order to cover this wide energy range, three different telescope types are envisaged, with different mirror sizes and focal plane features. In particular, for the highest energies a possible design is a dual-mirror Schwarzschild-Couder optical scheme, with a compact focal plane. A silicon photomultiplier (SiPM) based camera is being proposed as a solution to match the dimensions of the pixel (angular size of ~ 0.17 degrees). INFN is developing a camera demonstrator made by 9 Photo Sensor Modules (PSMs...

  4. The readout system of the MAGIC-II Cherenkov Telescope

    CERN Document Server

    Tescaro, D; Barcelo, M; Bitossi, M; Cortina, J; Fras, M; Hadasch, D; Illa, J M; Martínez, M; Mazin, D; Paoletti, R; Pegna, R

    2009-01-01

    In this contribution we describe the hardware, firmware and software components of the readout system of the MAGIC-II Cherenkov telescope on the Canary island La Palma. The PMT analog signals are transmitted by means of optical fibers from the MAGIC-II camera to the 80 m away counting house where they are routed to the new high bandwidth and fully programmable receiver boards (MONSTER), which convert back the signals from optical to electrical ones. Then the signals are split, one half provide the input signals for the level ONE trigger system while the other half is sent to the digitizing units. The fast Cherenkov pulses are sampled by low-power Domino Ring Sampler chips (DRS2) and temporarily stored in an array of 1024 capacitors. Signals are sampled at the ultra-fast speed of 2 GSample/s, which allows a very precise measurement of the signal arrival times in all pixels. They are then digitized with 12-bit resolution by an external ADC readout at 40 MHz speed. The Domino samplers are integrated in the newly...

  5. Workshop on Non-Imaging Cherenkov at High Energy

    CERN Document Server

    2013-01-01

    The non-Imaging Cherenkov air shower measurement technique holds great promise in furthering our understanding the Knee-to-Ankle region of the cosmic ray spectrum. In particular, this technique offers a unique way to determine the evolution of the cosmic ray nuclear composition, and an example is given by the recent spectrum results of the Tunka Collaboration. With this in mind, we are organizing a workshop, to be held at the University of Utah, to bring together the various practitioners of this cosmic ray measurement technique to share simulations, analyses, detector designs, and past experimental results amongst the community. The workshop will also be in support of our effort, NICHE, to extend the reach of the TA/TALE detector systems down to the Knee. We anticipate that the workshop will result in a white paper on the scientific importance of these high-energy cosmic ray measurements and on using the Cherenkov technique to accomplish them. Our goal is to have contributions from members of the previous ge...

  6. Measurements and simulations of Cherenkov light in lead fluoride crystals

    CERN Document Server

    Achenbach, P; Grimm, K; Hammel, T; Von Harrach, D; Ginja, A L; Maas, F E; Schilling, E P; Ströher, H

    2001-01-01

    The anticipated use of more than one thousand lead fluoride (PbF2) crystals as a fast and compact Cherenkov calorimeter material in a parity violation experiment at MAMI stimulated the investigation of the light yield (L.Y.) of these crystals. The number of photoelectrons (p.e.) per MeV deposited energy has been determined with a hybrid photomultiplier tube (HPMT). In response to radioactive sources a L.Y. between 1.7 and 1.9 p.e./MeV was measured with 4% statistical and 5% systematic error. The L.Y. optimization with appropriate wrappings and couplings was investigated by means of the HPMT. Furthermore, a fast Monte Carlo simulation based on the GEANT code was employed to calculate the characteristics of Cherenkov light in the PbF2 crystals. The computing time was reduced by a factor of 50 compared to the regular photon tracking method by implementing detection probabilities as a three-dimensional look-up table. For a single crystal a L.Y. of 2.1 p.e./MeV was calculated. The corresponding detector response t...

  7. The On-Site Analysis of the Cherenkov Telescope Array

    CERN Document Server

    Bulgarelli, Andrea; Zoli, Andrea; Aboudan, Alessio; Rodríguez-Vázquez, Juan José; De Cesare, Giovanni; De Rosa, Adriano; Maier, Gernot; Lyard, Etienne; Bastieri, Denis; Lombardi, Saverio; Tosti, Gino; Bergamaschi, Sonia; Beneventano, Domenico; Lamanna, Giovanni; Jacquemier, Jean; Kosack, Karl; Antonelli, Lucio Angelo; Boisson, Catherine; Borkowski, Jerzy; Buson, Sara; Carosi, Alessandro; Conforti, Vito; Colomé, Pep; Reyes, Raquel de los; Dumm, Jon; Evans, Phil; Fortson, Lucy; Fuessling, Matthias; Gotz, Diego; Graciani, Ricardo; Gianotti, Fulvio; Grandi, Paola; Hinton, Jim; Humensky, Brian; Inoue, Susumu; Knödlseder, Jürgen; Flour, Thierry Le; Lindemann, Rico; Malaguti, Giuseppe; Markoff, Sera; Marisaldi, Martino; Neyroud, Nadine; Nicastro, Luciano; Ohm, Stefan; Osborne, Julian; Oya, Igor; Rodriguez, Jerome; Rosen, Simon; Ribo, Marc; Tacchini, Alessandro; Schüssler, Fabian; Stolarczyk, Thierry; Torresi, Eleonora; Testa, Vincenzo; Wegner, Peter

    2015-01-01

    The Cherenkov Telescope Array (CTA) observatory will be one of the largest ground-based very high-energy gamma-ray observatories. The On-Site Analysis will be the first CTA scientific analysis of data acquired from the array of telescopes, in both northern and southern sites. The On-Site Analysis will have two pipelines: the Level-A pipeline (also known as Real-Time Analysis, RTA) and the level-B one. The RTA performs data quality monitoring and must be able to issue automated alerts on variable and transient astrophysical sources within 30 seconds from the last acquired Cherenkov event that contributes to the alert, with a sensitivity not worse than the one achieved by the final pipeline by more than a factor of 3. The Level-B Analysis has a better sensitivity (not be worse than the final one by a factor of 2) and the results should be available within 10 hours from the acquisition of the data: for this reason this analysis could be performed at the end of an observation or next morning. The latency (in part...

  8. Tagging Spallation Backgrounds with Showers in Water-Cherenkov Detectors

    CERN Document Server

    Li, Shirley Weishi

    2015-01-01

    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 ...

  9. FACT -- The G-APD revolution in Cherenkov astronomy

    CERN Document Server

    Bretz, T; Backes, M; Biland, A; Boccone, V; Braun, I; Buß, J; Cadoux, F; Commichau, V; Djambazov, L; Dorner, D; Einecke, S; Eisenacher, D; Gendotti, A; Grimm, O; von Gunten, H; Haller, C; Hempfling, C; Hildebrand, D; Horisberger, U; Huber, B; Kim, K S; Knoetig, M L; Köhne, J H; Krähenbühl, T; Krumm, B; Lee, M; Lorenz, E; Lustermann, W; Lyard, E; Mannheim, K; Meharga, M; Meier, K; Müuller, S; Montaruli, T; Neise, D; Nessi-Tedaldi, F; Overkemping, A K; Paravac, A; Pauss, F; Renker, D; Rhode, W; Ribordy, M; Röser, U; Stucki, J P; Schneider, J; Steinbring, T; Temme, F; Thaele, J; Tobler, S; Viertel, G; Vogler, P; Walter, R; Warda, K; Weitzel, Q; Zänglein, M

    2014-01-01

    Since two years, the FACT telescope is operating on the Canary Island of La Palma. Apart from its purpose to serve as a monitoring facility for the brightest TeV blazars, it was built as a major step to establish solid state photon counters as detectors in Cherenkov astronomy. The camera of the First G-APD Cherenkov Telesope comprises 1440 Geiger-mode avalanche photo diodes (G-APD), equipped with solid light guides to increase the effective light collection area of each sensor. Since no sense-line is available, a special challenge is to keep the applied voltage stable although the current drawn by the G-APD depends on the flux of night-sky background photons significantly varying with ambient light conditions. Methods have been developed to keep the temperature and voltage dependent response of the G-APDs stable during operation. As a cross-check, dark count spectra with high statistics have been taken under different environmental conditions. In this presentation, the project, the developed methods and the e...

  10. The water Cherenkov detectors of the HAWC Observatory

    Science.gov (United States)

    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.

  11. Open-structure composite mirrors for the Cherenkov Telescope Array

    CERN Document Server

    Dyrda, Michal; Niemiec, Jacek; Stodulski, Marek

    2013-01-01

    The Cherenkov Telescope Array (CTA) Observatory for high-energy gamma-ray astronomy will comprise several tens of imaging atmospheric Cherenkov telescopes (IACTs) of different size with a total reflective area of about 10,000 m$^2$. Here we present a new technology for the production of IACT mirrors that has been developed in the Institute of Nuclear Physics PAS in Krakow, Poland. An open-structure composite mirror consists of a rigid flat sandwich support structure and cast-in-mould spherical epoxy resin layer. To this layer a thin glass sheet complete with optical coating is cold-slumped to provide the spherical reflective layer of the mirror. The main components of the sandwich support structure are two flat float glass panels inter spaced with V-shape aluminum spacers of equal length. The sandwich support structure is open, thus enabling good cooling and ventilation of the mirror. A special arrangement of the aluminum spacers also prohibits water being trapped inside. The open-structure technology thus re...

  12. NECTAr: New electronics for the Cherenkov Telescope Array

    Energy Technology Data Exchange (ETDEWEB)

    Vorobiov, S., E-mail: vorobiov@lpta.in2p3.f [LPTA, Universite Montpellier II and IN2P3/CNRS, Montpellier (France); Bolmont, J.; Corona, P. [LPNHE, Universite Paris VI and IN2P3/CNRS, Paris (France); Delagnes, E. [IRFU/DSM/CEA, Saclay, Gif-sur-Yvette (France); Feinstein, F. [LPTA, Universite Montpellier II and IN2P3/CNRS, Montpellier (France); Gascon, D. [ICC-UB, Universitat Barcelona, Barcelona (Spain); Glicenstein, J.-F. [IRFU/DSM/CEA, Saclay, Gif-sur-Yvette (France); Naumann, C.L.; Nayman, P. [LPNHE, Universite Paris VI and IN2P3/CNRS, Paris (France); Sanuy, A. [ICC-UB, Universitat Barcelona, Barcelona (Spain); Toussenel, F.; Vincent, P. [LPNHE, Universite Paris VI and IN2P3/CNRS, Paris (France)

    2011-05-21

    The European astroparticle physics community aims to design and build the next generation array of Imaging Atmospheric Cherenkov Telescopes (IACTs), that will benefit from the experience of the existing H.E.S.S. and MAGIC detectors, and further expand the very-high energy astronomy domain. In order to gain an order of magnitude in sensitivity in the 10 GeV to >100TeV range, the Cherenkov Telescope Array (CTA) will employ 50-100 mirrors of various sizes equipped with 1000-4000 channels per camera, to be compared with the 6000 channels of the final H.E.S.S. array. A 3-year program, started in 2009, aims to build and test a demonstrator module of a generic CTA camera. We present here the NECTAr design of front-end electronics for the CTA, adapted to the trigger and data acquisition of a large IACTs array, with simple production and maintenance. Cost and camera performances are optimized by maximizing integration of the front-end electronics (amplifiers, fast analog samplers, ADCs) in an ASIC, achieving several GS/s and a few {mu}s readout dead-time. We present preliminary results and extrapolated performances from Monte Carlo simulations.

  13. A Compact High Energy Camera for the Cherenkov Telescope Array

    CERN Document Server

    Daniel, M K; Berge, D; Buckley, J; Chadwick, P M; Cotter, G; Funk, S; Greenshaw, T; Hidaka, N; Hinton, J; Lapington, J; Markoff, S; Moore, P; Nolan, S; Ohm, S; Okumura, A; Ross, D; Sapozhnikov, L; Schmoll, J; Sutcliffe, P; Sykes, J; Tajima, H; Varner, G S; Vandenbroucke, J; Vink, J; Williams, D

    2013-01-01

    The Compact High Energy Camera (CHEC) is a camera-development project involving UK, US, Japanese and Dutch institutes for the dual-mirror Small-Sized Telescopes (SST-2M) of the Cherenkov Telescope Array (CTA). Two CHEC prototypes, based on different photosensors are funded and will be assembled and tested in the UK over the next ~18 months. CHEC is designed to record flashes of Cherenkov light lasting from a few to a hundred nanoseconds, with typical RMS image width and length of ~0.2 x 1.0 degrees, and has a 9 degree field of view. The physical camera geometry is dictated by the telescope optics: a curved focal surface with radius of curvature 1m and diameter ~35cm is required. CHEC is designed to work with both the ASTRI and GATE SST-2M telescope structures and will include an internal LED flasher system for calibration. The first CHEC prototype will be based on multi-anode photomultipliers (MAPMs) and the second on silicon photomultipliers (SiPMs or MPPCs). The first prototype will soon be installed on the...

  14. The small size telescope projects for the Cherenkov Telescope Array

    CERN Document Server

    ,

    2015-01-01

    The small size telescopes (SSTs), spread over an area of several square km, dominate the CTA sensitivity in the photon energy range from a few TeV to over 100 TeV, enabling for the detailed exploration of the very high energy gamma-ray sky. The proposed telescopes are innovative designs providing a wide field of view. Two of them, the ASTRI (Astrophysics con Specchi a Tecnologia Replicante Italiana) and the GCT (Gamma-ray Cherenkov Telescope) telescopes, are based on dual mirror Schwarzschild-Couder optics, with primary mirror diameters of 4 m. The third, SST-1M, is a Davies-Cotton design with a 4 m diameter mirror. Progress with the construction and testing of prototypes of these telescopes is presented. The SST cameras use silicon photomultipliers, with preamplifier and readout/trigger electronics designed to optimize the performance of these sensors for (atmospheric) Cherenkov light. The status of the camera developments is discussed. The SST sub-array will consist of about 70 telescopes at the CTA souther...

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

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, Seiichi, E-mail: s-yama@met.nagoya-u.ac.jp [Department of Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine (Japan); Ogata, Yoshimune [Department of Radiological and Medical Laboratory Sciences, Nagoya University Graduate School of Medicine (Japan); Kawachi, Naoki; Suzui, Nobuo; Yin, Yong-Gen; Fujimaki, Shu [Radiotracer Imaging Group, Japan Atomic Energy Agency (Japan)

    2015-03-21

    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 {sup 137}Cs and {sup 134}Cs 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 {sup 137}Cs. 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 {sup 137}Cs point source, we obtained 220-μm spatial resolution in the Cherenkov light image. With a 1-mm diameter, 320-kBq {sup 137}Cs point source, the source was distinguished within 2-s. We successfully obtained Cherenkov light images of a plant whose root was dipped in a {sup 137}Cs 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.

  16. Study of TeV range cosmic ray detection with Cherenkov imaging techniques

    International Nuclear Information System (INIS)

    The Monte Carlo study of cosmic ray detection in the TeV energy range has been triggered by the authors' interest in the ARTEMIS (Antimatter Research Through the Earth Moon Ion Spectrometer) proposal. The properties of cosmic ray showers detected by Cherenkov imaging in the visible domain are studied. The detection sensitivity and the accuracy of the reconstruction of the parent particle direction using Cherenkov imaging are discussed. The backbone of the study is the atmospheric shower Monte Carlo generator developed by A.M. Hillas. A comparison between nucleon and photon induced showers of Cherenkov detection is also included. (R.P.) 14 refs., 48 figs., 3 tabs

  17. Cherenkov angle and charge reconstruction with the RICH detector of the AMS experiment

    CERN Document Server

    Barão, F; Borges, J; Gonçalves, P; Pimenta, M; Pérez, I

    2003-01-01

    The Alpha Magnetic Spectrometer experiment to be installed on the International Space Station will be equipped with a proximity focusing Ring Imaging Cherenkov (RICH) detector, for measurements of particle electric charge and velocity. In this note, two possible methods for reconstructing the Cherenkov angle and the electric charge with the RICH are discussed. A Likelihood method for the Cherenkov angle reconstruction was applied leading to a velocity determination for protons with a resolution of around 0.1%. The existence of a large fraction of background photons which can vary from event to event implied a charge reconstruction method based on an overall efficiency estimation on an event-by-event basis.

  18. Calculation of the Cherenkov light yield from electromagnetic cascades in ice with Geant4

    CERN Document Server

    Rädel, Leif

    2012-01-01

    In this work we investigate and parameterize the amount and angular distribution of Cherenkov photons which are generated by electro-magnetic cascades in water or ice. We simulate electromagnetic cascades with Geant-4 for primary electrons, positrons and photons with energies ranging from 1 GeV to 10 TeV. We parameterize the total Cherenkov light yield as a function of energy, the longitudinal evolution of the Cherenkov emission along the cascade-axis and the angular distribution of photons. Furthermore, we investigate the fluctuations of the total light yield, the fluctuations in azimuth and changes of the emission with increasing age of the cascade.

  19. A Pointing Solution for the Medium Size Telescopes for the Cherenkov Telescope Array

    CERN Document Server

    Tiziani, D; Oakes, L; Schwanke, U

    2016-01-01

    An important aspect of the calibration of the Cherenkov Telescope Array is the pointing, which enables an exact alignment of each telescope and therefore allows to transform a position in the sky to a point in the plane of the Cherenkov camera and vice versa. The favoured approach for the pointing calibration of the medium size telescopes (MST) is the installation of an optical CCD-camera in the dish of the telescope that captures the position of the Cherenkov camera and of the stars in the night sky simultaneously during data taking. The adaption of this approach is presented in this proceeding.

  20. Radiation

    International Nuclear Information System (INIS)

    The basic facts about radiation are explained, along with some simple and natural ways of combating its ill-effects, based on ancient healing wisdom as well as the latest biochemical and technological research. Details are also given of the diet that saved thousands of lives in Nagasaki after the Atomic bomb attack. Special comment is made on the use of radiation for food processing. (U.K.)

  1. First year results of the High Altitude Water Cherenkov observatory

    CERN Document Server

    Carramiñana, Alberto

    2016-01-01

    The High Altitude Water Cherenkov (HAWC) gamma-ray observatory is a wide field of view (1.8 Sr) and high duty cycle (>95% up-time) detector of unique capabilities for the study of TeV gamma-ray sources. Installed at an altitude of 4100m in the Northern slope of Volc\\'an Sierra Negra, Puebla, by a collaboration of about thirty institutions of Mexico and the United States, HAWC has been in full operations since March 2015, surveying 2/3 of the sky every sidereal day, monitoring active galaxies and mapping sources in the Galactic Plane to a detection level of 1 Crab per day. This contribution summarizes the main results of the first year of observations of the HAWC gamma-ray observatory.

  2. Building Medium Size Telescope Structures for the Cherenkov Telescope Array

    CERN Document Server

    Schulz, A; Oakes, L; Schlenstedt, S; Schwanke, U

    2016-01-01

    The Cherenkov Telescope Array (CTA) is the future instrument in ground-based gamma-ray astronomy in the energy range from 20 GeV to 300 TeV. Its sensitivity will surpass that of current generation experiments by a factor $\\sim$10, facilitated by telescopes of three sizes. The performance in the core energy regime will be dominated by Medium Size Telescopes (MST) with a reflector of 12 m diameter. A full-size mechanical prototype of the telescope structure has been constructed in Berlin. The performance of the prototype is being evaluated and optimisations, among others, facilitating the assembly procedure and mass production possibilities are being implemented. We present the current status of the developments from prototyping towards pre-production telescopes, which will be deployed at the final site.

  3. Application of Geiger-mode photosensors in Cherenkov detectors

    Science.gov (United States)

    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.

  4. Early attempts at atmospheric simulations for the Cherenkov Telescope Array

    CERN Document Server

    Rulten, Cameron B

    2014-01-01

    The Cherenkov Telescope Array (CTA) will be the world's first observatory for detecting gamma-rays from astrophysical phenomena and is now in its prototyping phase with construction expected to begin in 2015/16. In this work we present the results from early attempts at detailed simulation studies performed to assess the need for atmospheric monitoring. This will include discussion of some lidar analysis methods with a view to determining a range resolved atmospheric transmission profile. We find that under increased aerosol density levels, simulated gamma-ray astronomy data is systematically shifted leading to softer spectra. With lidar data we show that it is possible to fit atmospheric transmission models needed for generating lookup tables, which are used to infer the energy of a gamma-ray event, thus making it possible to correct affected data that would otherwise be considered unusable.

  5. Signal Temporal Profile of a Water Cherenkov Detector

    Science.gov (United States)

    Salazar, H.; Martinez, O.; Cotzomi, J.; Moreno, E.; Villaseñor, L.

    2003-07-01

    The suggested existence of temporal structure in the signals of extensive air showers (EAS) for energies greater than 1017 eV at core distances of about 500 m, and its correlation with important parameters of EASs has stimulated us to study this structure for showers with lower energies in an Auger water Cherenkov detector(WCD). Preliminary analysis of experimental data on the widths of signals in a WCD and their correlation with other parameters of the signal are presented. The detector was triggered by the EAS-BUAP array which operates in the region of 1014 - 1016 eV. The distance of the WCD to the EAS core is larger than 30 m.

  6. FACT: Towards Robotic Operation of an Imaging Air Cherenkov Telescope

    CERN Document Server

    Biland, A; Backes, M; Boccone, V; Braun, I; Bretz, T; Buss, J; Cadoux, F; Commichau, V; Djambazov, L; Dorner, D; Einecke, S; Eisenacher, D; Gendotti, A; Grimm, O; von Gunten, H; Haller, C; Hildebrand, D; Horisberger, U; Huber, B; Kim, K -S; Knoetig, M L; Koehne, J -H; Kraehenbuehl, T; Krumm, B; Lee, M; Lorenz, E; Lustermann, W; Lyard, E; Mannheim, K; Meharga, M; Meier, K; Montaruli, T; Neise, D; Nessi-Tedaldi, F; Overkemping, A -K; Paravac, A; Pauss, F; Renker, D; Rhode, W; Ribordy, M; Roeser, U; Stucki, J -P; Schneider, J; Steinbring, T; Temme, F; Thaele, J; Tobler, S; Viertel, G; Vogler, P; Walter, R; Warda, K; Weitzel, Q; Zaenglein, M

    2013-01-01

    The First G-APD Cherenkov Telescope (FACT) became operational at La Palma in October 2011. Since summer 2012, due to very smooth and stable operation, it is the first telescope of its kind that is routinely operated from remote, without the need for a data-taking crew on site. In addition, many standard tasks of operation are executed automatically without the need for manual interaction. Based on the experience gained so far, some alterations to improve the safety of the system are under development to allow robotic operation in the future. We present the setup and precautions used to implement remote operations and the experience gained so far, as well as the work towards robotic operation.

  7. Data compression for the First G-APD Cherenkov Telescope

    CERN Document Server

    Ahnen, M L; Bergmann, M; Biland, A; Bretz, T; Buß, J; Dorner, D; Einecke, S; Freiwald, J; Hempfling, C; Hildebrand, D; Hughes, G; Lustermann, W; Lyard, E; Mannheim, K; Meier, K; Mueller, S; Neise, D; Neronov, A; Overkemping, A -K; Paravac, A; Pauss, F; Rhode, W; Steinbring, T; Temme, F; Thaele, J; Toscano, S; Vogler, P; Walter, R; Wilbert, A

    2015-01-01

    The First Geiger-mode Avalanche photodiode (G-APD) Cherenkov Telescope (FACT) has been operating on the Canary island of La Palma since October 2011. Operations were automated so that the system can be operated remotely. Manual interaction is required only when the observation schedule is modified due to weather conditions or in case of unexpected events such as a mechanical failure. Automatic operations enabled high data taking efficiency, which resulted in up to two terabytes of FITS files being recorded nightly and transferred from La Palma to the FACT archive at ISDC in Switzerland. Since long term storage of hundreds of terabytes of observations data is costly, data compression is mandatory. This paper discusses the design choices that were made to increase the compression ratio and speed of writing of the data with respect to existing compression algorithms. Following a more detailed motivation, the FACT compression algorithm along with the associated I/O layer is discussed. Eventually, the performances...

  8. An Innovative Workspace for The Cherenkov Telescope Array

    CERN Document Server

    Costa, Alessandro; Becchini, Ugo; Massimino, Piero; Riggi, Simone; Sanchez, David; Vitello, Fabio

    2016-01-01

    The Cherenkov Telescope Array (CTA) is an initiative to build the next generation, ground-based gamma-ray observatories. We present a prototype workspace developed at INAF that aims at providing innovative solutions for the CTA community. The workspace leverages open source technologies providing web access to a set of tools widely used by the CTA community. Two different user interaction models, connected to an authentication and authorization infrastructure, have been implemented in this workspace. The first one is a workflow management system accessed via a science gateway (based on the Liferay platform) and the second one is an interactive virtual desktop environment. The integrated workflow system allows to run applications used in astronomy and physics researches into distributed computing infrastructures (ranging from clusters to grids and clouds). The interactive desktop environment allows to use many software packages without any installation on local desktops exploiting their native graphical user i...

  9. The SST-1M camera for the Cherenkov Telescope Array

    CERN Document Server

    Schioppa, E J; Christov, A.; della Volpe, D.; Favre, Y.; Heller, M.; Montaruli, T.; Porcelli, A.; Rameez, M.; Pujadas, I. Troyano; Bilnik, W.; Blocki, J.; Bogacz, L.; Bulik, T.; Curylo, M.; Dyrda, M.; Frankowski, A.; Grudniki, L.; Grudzinska, M.; Idzkowski, B.; Jamrozy, M.; Janiak, M.; Kasperek, J.; Lalik, K.; Lyard, E.; Mach, E.; Mandat, D.; Marszalek, A.; Michaowski, J.; Moderski, R.; Neronov, A.; Niemiec, J.; Ostrowski, M.; Pasko, P.; Pech, M.; Prandini, E.; Rajda, P.; Schovanek, P.; Seweryn, K.; Skowron, K.; Sliusar, V.; Sowinski, M.; Stawarz, L.; Stodulska, M.; Stodulski, M.; Toscano, S.; Walter, R.; Wiecek, M.; Zagdanski, A.; Zietara, K.; Zychowski, P.

    2015-01-01

    The prototype camera of the single-mirror Small Size Telescopes (SST-1M) proposed for the Cherenkov Telescope Array (CTA) project has been designed to be very compact and to deliver high performance over thirty years of operation. The camera is composed of an hexagonal photo-detection plane made of custom designed large area hexagonal silicon photomultipliers and a high throughput, highly configurable, fully digital readout and trigger system (DigiCam). The camera will be installed on the telescope structure at the H. Niewodnicza{\\'n}ski institute of Nuclear Physics in Krakow in fall 2015. In this contribution, we review the steps that led to the development of the innovative photo-detection plane and readout electronics, and we describe the test and calibration strategy adopted.

  10. Charged Kaon Mass Measurement using the Cherenkov Effect

    CERN Document Server

    Graf, N; Abrams, R J; Akgun, U; Aydin, G; Baker, W; Barnes, P D; Bergfeld, T; Beverly, L; Bujak, A; Carey, D; Dukes, C; Duru, F; Feldman, G J; Godley, A; Gülmez, E; Günaydın, Y O; Gustafson, H R; Gutay, L; Hartouni, E; Hanlet, P; Hansen, S; Heffner, M; Johnstone, C; Kaplan, D; Kamaev, O; Kilmer, J; Klay, J; Kostin, M; Lange, D; Ling, J; Longo, M J; Lu, L C; Materniak, C; Messier, M D; Meyer, H; Miller, D E; Mishra, S R; Nelson, K; Nigmanov, T; Norman, A; Onel, Y; Paley, J M; Park, H K; Penzo, A; Peterson, R J; Raja, R; Rajaram, D; Ratnikov, D; Rosenfeld, C; Rubin, H; Seun, S; Solomey, N; Soltz, R; Swallow, E; Schmitt, R; Subbarao, P; Torun, Y; Tope, T E; Wilson, K; Wright, D; Wu, K

    2009-01-01

    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^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.

  11. Gamma-Hadron Separation Methods for the VERITAS Array of Four Imaging Atmospheric Cherenkov Telescopes

    CERN Document Server

    Krawczynski, H; Duke, C; Holder, J; Le Bohec, S; Maier, G; Sembroski, G

    2006-01-01

    Ground-based arrays of imaging atmospheric Cherenkov telescopes have emerged as the most sensitive gamma-ray detectors in the energy range of about 100 GeV and above. The strengths of these arrays are a very large effective collection area on the order of 100,000 square meter, combined with excellent single photon angular and energy resolutions. The sensitivity of such detectors is limited by statistical fluctuations in the number of Cosmic Ray initiated air showers that resemble gamma-ray air showers in many ways. In this paper, we study the performance of simple event reconstruction methods when applied to simulated data of the Very Energetic Radiation Imaging Telescope Array System (VERITAS) experiment. We review methods for reconstructing the arrival direction and the energy of the primary photons, and examine means to improve on their performance. For a software threshold energy of 300 GeV (100 GeV), the methods achieve point source angular and energy resolutions of sigma[63%]= 0.1 degree (0.2 degree) an...

  12. Superradiance driven by coherent spontaneous emission in a Cherenkov free-electron maser amplifier

    CERN Document Server

    Jaroszynski, D A; McNeil, B W J; Robb, G R M; Aitken, P; Phelps, A D R; Cross, A W; Ronald, K; Shpak, V G; Yalandin, M I; Ginzburg, N S

    2000-01-01

    Superradiance (SR) initiated by coherent spontaneous emission (CSE) has been studied in a 35 GHz high gain free-electron Cherenkov maser. We present experimental results that show the development of ultra-short pulses of radiation in the non-linear superradiant regime which are characterised by a quadratic dependence of the intensity on the current. The self-similar pulses that develop have a duration that scales inversely with the fourth root of the intensity leading to three cycle long pulses at the highest intensity (few MW). The non-linear SR regime is preceded by a stage of linear exponential growth of the microwave pulses with a gain length of 1 cm. The superradiant pulse is shown to evolve from a CSE seed by extrapolating the growth curve. Further confirmation of CSE has been obtained by varying the current pulse shape. By varying the slope of the leading edge, and thus the Fourier components of the longitudinal spectral density, we are able to vary the strength of the CSE source. We compare the experi...

  13. ``Super'' Gas Cherenkov Detector for Gamma Ray Measurements at the National Ignition Facility

    Science.gov (United States)

    Herrmann, Hans W.; Kim, Y. H.; McEvoy, A. M.; Zylstra, A. B.; Lopez, F. E.; Griego, J. R.; Fatherley, V. E.; Oertel, J. A.; Batha, S. H.; Stoeffl, W.; Church, J. A.; Carpenter, A.; Rubery, M. S.; Horsfield, C. J.; Gales, S.; Leatherland, A.; Hilsabeck, T.; Kilkenny, J. D.; Malone, R. M.; Shmayda, W. T.

    2015-11-01

    New requirements to improve reaction history and ablator areal density measurements at the NIF necessitate improvements in sensitivity, temporal and spectral response relative to the existing Gamma Reaction History diagnostic (GRH-6m) located 6 meters from target chamber center (TCC). A new DIM-based ``Super'' Gas Cherenkov Detector (GCD) will ultimately provide ~ 200x more sensitivity to DT fusion gamma rays, reduce the effective temporal resolution from ~ 100 to ~ 10 ps and lower the energy threshold from 2.9 to 1.8 MeV, relative to GRH-6m. The first phase is to insert the existing coaxial GCD-3 detector into a reentrant well on the NIF chamber which will put it within 4 meters of TCC. This diagnostic platform will allow assessment of the x-ray radiation background environment within the well which will be fed into the shielding design for the follow-on ``Super'' GCD. It will also enable use of a pulse-dilation PMT which has the potential to improve the effective measurement bandwidth by ~ 10x relative to current PMT technology. GCD-3 has been thoroughly tested at the OMEGA Laser Facility and characterized at the High Intensity Gamma Ray Source (HIgS).

  14. Beam Tests of the Second Prototype of a Cherenkov Counter for the ALICE T0 Detector

    CERN Document Server

    Kaplin, V A; CERN. Geneva; Loginov, V A; Rakhmanov, A L; Kurepin, A B; Maevskaya, A I; Rasin, V I; Reshetin, A I; Akindinov, A V; Martemyanov, A N; Sheinkman, V A; Smirnitsky, A V; Grigoriev, V A

    2000-01-01

    Abstract The second prototype of a Cherenkov counter consisting of a quartz radiator (cylinder 26 mm in diameter, 30 mm long) and a PMT Hamamatsu R3432-01 has been tested in a 1.28 GeV/c pion beam. A constant fraction discriminator EG&G was used at the output of the PMT. Measurements in a beam with a limited cross-section 0.8 x 0.8 cm2 gave a 50 ps time resolution of the detector. In a "broad-beam" geometry the time resolution of the detector was measured to be 55 ps. In both cases an off-line correction was used due to inadequate characteristics of the CFD, confirmed by the measurements at laboratory conditions using a pulsed laser. Another type of a CFD (4000M) properly adjusted using a pulsed laser and optical filters provided a 55 ps resolution in a "broad-beam" geometry without any off-line correction. Monte-Carlo simulations of p-p collisions show, that an averaging procedure for the signals coming from the two arrays of the T0 detector significantly improves the time resolution for the T0 sig...

  15. TARGET: toward a solution for the readout electronics of the Cherenkov Telescope Array

    CERN Document Server

    Tibaldo, L; Albert, A M; Funk, S; Kawashima, T; Kraus, M; Okumura, A; Sapozhnikov, L; Tajima, H; Varner, G S; Wu, T; Zink, A

    2015-01-01

    TARGET is an application specific integrated circuit (ASIC) designed to read out signals recorded by the photosensors in cameras of very-high-energy gamma-ray telescopes exploiting the imaging of Cherenkov radiation from atmospheric showers. TARGET capabilities include sampling at a high rate (typically 1 GSample/s), digitization, and triggering on the sum of four adjacent pixels. The small size, large number of channels read out per ASIC (16), low cost per channel, and deep buffer for trigger latency (~16 $\\mu$s at 1 GSample/s) make TARGET ideally suited for the readout in systems with a large number of telescopes instrumented with compact photosensors like multi-anode or silicon photomultipliers combined with dual-mirror optics. The possible advantages of such systems are better sensitivity, a larger field of view, and improved angular resolution. The two latest generations of TARGET ASICs, TARGET 5 and TARGET 7, are soon to be used for the first time in two prototypes of small-sized and medium-sized dual-m...

  16. Sensitivity of the Cherenkov Telescope Array to the Detection of Intergalactic Magnetic Fields

    Science.gov (United States)

    Meyer, Manuel; Conrad, Jan; Dickinson, Hugh

    2016-08-01

    Very high energy (VHE; energy E ≳ 100 GeV) γ-rays originating from extragalactic sources undergo pair production with low-energy photons of background radiation fields. These pairs can inverse-Compton-scatter background photons, initiating an electromagnetic cascade. The spatial and temporal structure of this secondary γ-ray signal is altered as the {e}+{e}- pairs are deflected in an intergalactic magnetic field (IGMF). We investigate how VHE observations with the future Cherenkov Telescope Array, with its high angular resolution and broad energy range, can potentially probe the IGMF. We identify promising sources and simulate γ-ray spectra over a wide range of values of the IGMF strength and coherence length using the publicly available ELMAG Monte Carlo code. Combining simulated observations in a joint likelihood approach, we find that current limits on the IGMF can be significantly improved. The projected sensitivity depends strongly on the time a source has been γ-ray active and on the emitted maximum γ-ray energy.

  17. Using Cherenkov Counting For Fast Determination of 90Sr/90Y Activity in Milk

    International Nuclear Information System (INIS)

    90Sr is one of the main long-lived fission products, and it is transferred into human body primarily by food, with milk being a substantial contributor. Due to its biochemical similarity to calcium, most strontium is efficiently incorporated into bone tissues. 90Sr is characterized by a long physical half life (28.8 y) and decays by beta particles with an Emax of 0.546 MeV to 90Y. This daughter isotope has a half life of 64 h and decays into 90Zr by beta particles with an Emax of 2.284 MeV. The milk components produce a high turbidity and light attenuation, causing a significant decrease of the counting efficiency in liquid scintillation counting (LSC) systems, mostly used for beta emitters detection. Most methods proposed in the past are time-consuming, as they are based on several stages of chemical and physical treatments, including precipitation, ashing, ion exchange and extraction (Wikins et al., 1984, Porter et al, 1961, Kimura et al., 1979). When measuring 90Sr/90Y activity by Cherenkov counting, most of the Cherenkov radiation is produced by 90Y (about 98.6%), due to the much higher energy of its beta particles relative to these from 90Sr. The counting efficiency varies strongly with color quenching, at a greater extent than in standard liquid scintillation counting (L'Annunziata, 2012), and therefore the quench correction is critical. The ‘‘external source area ratio’’ (ESAR) quench correction method was applied to measure 90Sr/90Y activities in aqueous samples with a wide range of quenching levels (Tsroya et al., 2009). This method was proved to be superior to all other quench correction methods (Tsroya et al., 2012) and is applicable also for determination of 90Sr/90Y in human urine (Tsroya et al., 2013). In the present work the applicability of the ESAR method to measurement of 90Sr/90Y activities in milk and some of its products was investigated

  18. Ionospheric propagation effects for UHE neutrino detection with the lunar Cherenkov technique

    CERN Document Server

    McFadden, Rebecca; Bray, Justin

    2013-01-01

    Lunar Cherenkov experiments aim to detect nanosecond pulses of Cherenkov emission produced during UHE cosmic ray or neutrino interactions in the lunar regolith. Pulses from these interactions are dispersed, and therefore reduced in amplitude, during propagation through the Earth's ionosphere. Pulse dispersion must therefore be corrected to maximise the received signal to noise ratio and subsequent chances of detection. The pulse dispersion characteristic may also provide a powerful signature to determine the lunar origin of a pulse and discriminate against pulses of terrestrial radio frequency interference (RFI). This characteristic is parameterised by the instantaneous Total Electron Content (TEC) of the ionosphere and therefore an accurate knowledge of the ionospheric TEC provides an experimental advantage for the detection and identification of lunar Cherenkov pulses. We present a new method to calibrate the dispersive effect of the ionosphere on lunar Cherenkov pulses using lunar Faraday rotation measurem...

  19. Studies on the Cherenkov Effect for Improved Time Resolution of TOF-PET

    CERN Document Server

    Brunner, S E; Marton, J; Suzuki, K; Hirtl, A

    2013-01-01

    With the newly gained interest in the time of flight method for positron emission tomography (TOF-PET), many options for pushing the time resolution to its borders have been investigated. As one of these options the exploitation of the Cherenkov effect has been proposed, since it allows to bypass the scintillation process and therefore provides almost instantaneous response to incident 511keV annihilation photons. Our simulation studies on the yield of Cherenkov photons, their arrival rate at the photon detector and their angular distribution reveal a significant influence by Cherenkov photons on the rise time of inorganic scintillators - a key-parameter for TOF in PET. A measurement shows the feasibility to detect Cherenkov photons in this low energy range.

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

    Indian Academy of Sciences (India)

    A. A. Al-Rubaiee

    2014-12-01

    The Cherenkov light Lateral Distribution Function (LDF) from particles initiated Extensive Air Showers (EAS) with ultrahigh energies ( > 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.

  1. Simulated response of Cherenkov glass detectors to MeV photons

    Energy Technology Data Exchange (ETDEWEB)

    Hayward, J P [University of Tennessee, Knoxville (UTK); Bell, Zane W [ORNL; Boatner, Lynn A [ORNL; Hobbs, C. L. [University of Tennessee, Knoxville (UTK); Johnson, Rose E [ORNL; Ramey, Joanne Oxendine [ORNL; Jellison Jr, Gerald Earle [ORNL

    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.

  2. Ionospheric propagation effects for UHE neutrino detection with the lunar Cherenkov technique

    OpenAIRE

    McFadden, Rebecca; Ekers, Ron; Bray, Justin

    2013-01-01

    Lunar Cherenkov experiments aim to detect nanosecond pulses of Cherenkov emission produced during UHE cosmic ray or neutrino interactions in the lunar regolith. Pulses from these interactions are dispersed, and therefore reduced in amplitude, during propagation through the Earth's ionosphere. Pulse dispersion must therefore be corrected to maximise the received signal to noise ratio and subsequent chances of detection. The pulse dispersion characteristic may also provide a powerful signature ...

  3. Photosensor Characterization for the Cherenkov Telescope Array: Silicon Photomultiplier versus Multi-Anode Photomultiplier Tube

    OpenAIRE

    Bouvier, Aurelien; Gebremedhin, Lloyd; Johnson, Caitlin; Kuznetsov, Andrey; Williams, David; Otte, Nepomuk; Strausbaugh, Robert; Hidaka, Naoya; Tajima, Hiroyasu; Hinton, Jim; White, Richard; Errando, Manel; Mukherjee, Reshmi

    2013-01-01

    Photomultiplier tube technology has been the photodetector of choice for the technique of imaging atmospheric Cherenkov telescopes since its birth more than 50 years ago. Recently, new types of photosensors are being contemplated for the next generation Cherenkov Telescope Array. It is envisioned that the array will be partly composed of telescopes using a Schwarzschild-Couder two mirror design never built before which has significantly improved optics. The camera of this novel optical design...

  4. Measurable difference in Cherenkov light between gamma and hadron induced EAS

    Energy Technology Data Exchange (ETDEWEB)

    Cabot, H.; Meynadier, Ch. [Universite de Perpignan, Groupe de Physique Fondamentale, Perpignan (France); Sobczynska, D. [Experimental Physics Department, University of Lodz, Lodz (Poland); Szabelska, B. [Soltan Institute for Nuclear Studies, Lodz (Poland); Szabelski, J. [Universite de Perpignan, Groupe de Physique Fondamentale, Perpignan (France)]|[Soltan Institute for Nuclear Studies, Lodz (Poland); Wibig, T. [Experimental Physics Department, University of Lodz, Lodz (Poland)

    1997-12-31

    We describe the possibly measurable difference in the Cherenkov light component of EAS induced by en electromagnetic particle (i.e. e{sup +}, e{sup -} or {gamma}) and induced by a hadron (i.e. proton or heavier nuclei) in TeV range. The method can be applied in experiments which use wavefront sampling method of EAS Cherenkov light detection (e.g. THEMISTOCLE, ASGAT). (author) 16 refs, 9 figs

  5. Prototyping the graphical user interface for the operator of the Cherenkov Telescope Array

    OpenAIRE

    Sadeh, Iftach; Oya, Igor; Schwarz, Joseph; Pietriga, Emmanuel

    2016-01-01

    The Cherenkov Telescope Array (CTA) is a planned gamma-ray observatory. CTA will incorporate about 100 imaging atmospheric Cherenkov telescopes (IACTs) at a Southern site, and about 20 in the North. Previous IACT experiments have used up to five telescopes. Subsequently, the design of a graphical user interface (GUI) for the operator of CTA involves new challenges. We present a GUI prototype, the concept for which is being developed in collaboration with experts from the field of Human-Comput...

  6. The performance of a prototype array of water Cherenkov detectors for the LHAASO project

    International Nuclear Information System (INIS)

    A large high-altitude air-shower observatory (LHAASO) is to be built at Shangri-La, Yunnan Province, China. This observatory is intended to conduct sub-TeV gamma astronomy, and as an important component of the LHAASO project, a water Cherenkov detector array (WCDA) is proposed. To investigate engineering issues and fully understand the water Cherenkov technique for detecting air showers, a prototype array at 1% scale of the LHAASO-WCDA has been built at Yang-Ba-Jing, Tibet, China. This paper introduces the prototype array setup and studies its performance by counting rate of each photomultiplier tube (PMT), trigger rates at different PMT multiplicities, and responses to air showers. Finally, the reconstructed shower directions and angular resolutions of the detected showers for the prototype array are given. -- Highlights: • The technique of the water Cherenkov array is studied. • Engineering issues of the water Cherenkov array are investigated. • The PMTs and electronics of the water Cherenkov array are tested. • Some key parameters of the water Cherenkov array are measured

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

    Energy Technology Data Exchange (ETDEWEB)

    Naumann, C.L., E-mail: christopher.naumann@lpnhe.in2p3.fr [LPNHE, IN2P3/CNRS Universite Paris VI and Universite Paris VII and IN2P3/CNRS, Paris (France); Delagnes, E. [IRFU, CEA/DSM, Saclay, Gif-sur-Yvette (France); Bolmont, J.; Corona, P. [LPNHE, IN2P3/CNRS Universite Paris VI and Universite Paris VII and IN2P3/CNRS, Paris (France); Dzahini, D. [LPSC, Universite Joseph Fourier, INPG and IN2P3/CNRS, Grenoble (France); Feinstein, F. [LUPM, Universite Montpellier II and IN2P3/CNRS, Montpellier (France); Gascon, D. [ICC-UB, Universitat Barcelona (Spain); Glicenstein, J.-F.; Guilloux, F. [IRFU, CEA/DSM, Saclay, Gif-sur-Yvette (France); Nayman, P. [LPNHE, IN2P3/CNRS Universite Paris VI and Universite Paris VII and IN2P3/CNRS, Paris (France); Rarbi, F. [LPSC, Universite Joseph Fourier, INPG and IN2P3/CNRS, Grenoble (France); Sanuy, A. [ICC-UB, Universitat Barcelona (Spain); Tavernet, J.-P.; Toussenel, F.; Vincent, P. [LPNHE, IN2P3/CNRS Universite Paris VI and Universite Paris VII and IN2P3/CNRS, Paris (France); Vorobiov, S. [LUPM, Universite Montpellier II and IN2P3/CNRS, Montpellier (France); DESY Zeuthen, Platanenallee 6, 15738 Zeuthen (Germany)

    2012-12-11

    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

  8. Interaction of Radiation with Matter

    Science.gov (United States)

    Horváth, D.; Vértes, A.

    The effects of interactions of the various kinds of nuclear radiation with matter are summarized with special emphasis on relations to nuclear chemistry and possible applications. The Bethe-Bloch theory describes the slowing down process of heavy charged particles via ionization, and it is modified for electrons and photons to include radiation effects like bremsstrahlung and pair production. Special emphasis is given to processes involved in particle detection, the Cherenkov effect and transition radiation. Useful formulae, numerical constants, and graphs are provided to help calculations of the stopping power of particles in simple and composite materials.

  9. Strange meson spectroscopy in Kω and Kφ at 11 GeV/c and Cherenkov ring imaging at SLD

    International Nuclear Information System (INIS)

    This thesis consists of two independent parts; development of Cherenkov Ring Imaging Detector (CRID) system and analysis of high-statistics data of strange meson reactions from the LASS spectrometer. Part 1: The CRID system is devoted to charged particle identification in the SLAC Large Detector (SLD) to study e+e- collisions at √s = mZ0. By measuring the angles of emission of the Cherenkov photons inside liquid and gaseous radiators, π/K/p separation will be achieved up to ∼30 GeV/c. The signals from CRID are read in three coordinates, one of which is measured by charge-division technique. To obtain a ∼1% spatial resolution in the charge-division, low-noise CRID preamplifier prototypes were developed and tested resulting in 5 gain. To help ensure the long-term stability of CRID operation at high efficiency, a comprehensive monitoring and control system was developed. Part 2: Results from the partial wave analysis of strange meson final states in the reactions K-p → K-ωp and K-p → bar K0φn are presented. The analyses are based on data from a 4.1 event/nb exposure of the LASS spectrometer in K-p interactions at 11 GeV/c. The data sample of K-ωp final state contains ∼105 events. From the partial wave analysis, resonance structures of JP = 2-, 3- and 2+ amplitudes are observed in the Kω system. The analysis of 2- amplitudes provides an evidence for two strange meson states in the mass region around 1.75 GeV/c2. The appropriate branching fractions are calculated and compared with the SU(3) predictions. The partial wave analysis of bar K0φ system favors JP = 1- and 2+ states in the 1.9--2.0 GeV/c2 region

  10. Development of Ring Imaging Cherenkov Detectors for LHCb

    CERN Document Server

    Bellunato, T; Matteuzzi, C

    2003-01-01

    The work described in this thesis has been carried out in the framework of the development program of the Ring Imaging Cherenkov (RICH) detectors of the LHCb experiment. LHCb will operate at the Large Hadron Collider at CERN, and it will perform a wide range of measurements in the b-hadrons realm. The extensive study of CP violation and rare decays in the b-hadron system are the main goals of the experiment. An introduction to CP violation in hadronic interactions is given in chapter 1. The high b-b bar production cross section at the LHC energy will provide an unprecedented amount of data which will give LHCb a unique opportunity for precision tests on a large set of physics channels as well as a promising discovery potential for sources of CP violation arising from physics beyond the Standard Model. The experiment is designed in such a way to optimally match the kinematic structure of events where a pair of b quarks is produced in the collision between to 7 GeV protons. Chapter 2 is devoted to an overview o...

  11. Design constraints on Cherenkov telescopes with Davies-Cotton reflectors

    CERN Document Server

    Bretz, Thomas

    2013-01-01

    This paper discusses the construction of high-performance ground-based gamma-ray Cherenkov telescopes with a Davies-Cotton reflector. For the design of such telescopes, usually physics constrains the field-of-view, while the photo-sensor size is defined by limited options. Including the effect of light-concentrators in front of the photo sensor, it is demonstrated that these constraints are enough to mutually constrain all other design parameters. The dependability of the various design parameters naturally arises once a relationship between the value of the point-spread functions at the edge of the field-of-view and the pixel field-of-view is introduced. To be able to include this constraint into a system of equations, an analytical description for the point-spread function of a tessellated Davies-Cotton reflector is derived from Taylor developments and ray-tracing simulations. Including higher order terms renders the result precise on the percent level. Design curves are provided within the typical phase sp...

  12. An outdoor test facility for the Cherenkov Telescope Array mirrors

    CERN Document Server

    Medina, M C; Maya, J; Mancilla, A; Larrarte, J J; Rasztocky, E; Benitez, M; Dipold, J; Platino, M

    2013-01-01

    The Cherenkov Telescopes Array (CTA) is planned to be an Observatory for very high energy gamma ray astronomy and will consist of several tens of telescopes which account for a reflective surface of more than 10000 m$^2$. The mirrors of these telescopes will be formed by a set of facets. Different technological solutions, for a fast and cost efficient production of light-weight mirror facets are under test inside the CTA Consortium. Most of them involve composite structures whose behavior under real observing conditions is not yet fully tested. An outdoor test facility has been built in one of the candidate sites for CTA, in Argentina (San Antonio de los Cobres [SAC], 3600m a.s.l) in order to monitor the optical and mechanical properties of these facets exposed to the local atmospheric conditions for a given period of time. In this work we present the preliminary results of the first Middle Size Telescope (MST) mirror-monitoring campaign, started in 2013.

  13. Monte Carlo design studies for the Cherenkov Telescope Array

    CERN Document Server

    Bernlöhr, K; Becherini, Y; Bigas, O Blanch; Carmona, E; Colin, P; Decerprit, G; Di Pierro, F; Dubois, F; Farnier, C; Funk, S; Hermann, G; Hinton, J A; Humensky, T B; Khélifi, B; Kihm, T; Komin, N; Lenain, J -P; Maier, G; Mazin, D; Medina, M C; Moralejo, A; Nolan, S J; Ohm, S; Wilhelmi, E de Oña; Parsons, R D; Arribas, M Paz; Pedaletti, G; Pita, S; Prokoph, H; Rulten, C B; Schwanke, U; Shayduk, M; Stamatescu, V; Vallania, P; Vorobiov, S; Wischnewski, R; Yoshikoshi, T; Zech, A

    2012-01-01

    The Cherenkov Telescopes Array (CTA) is planned as the future instrument for very-high-energy (VHE) gamma-ray astronomy with a wide energy range of four orders of magnitude and an improvement in sensitivity compared to current instruments of about an order of magnitude. Monte Carlo simulations are a crucial tool in the design of CTA. The ultimate goal of these simulations is to find the most cost-effective solution for given physics goals and thus sensitivity goals or to find, for a given cost, the solution best suited for different types of targets with CTA. Apart from uncertain component cost estimates, the main problem in this procedure is the dependence on a huge number of configuration parameters, both in specifications of individual telescope types and in the array layout. This is addressed by simulation of a huge array intended as a superset of many different realistic array layouts, and also by simulation of array subsets for different telescope parameters. Different analysis methods -- in use with cu...

  14. Status of the Cherenkov Telescope Array's Large Size Telescopes

    CERN Document Server

    Cortina, J

    2015-01-01

    The Cherenkov Telescope Array (CTA) observatory, will be deployed over two sites in the two hemispheres. Both sites will be equipped with four Large Size Telescopes (LSTs), which are crucial to achieve the science goals of CTA in the 20-200 GeV energy range. Each LST is equipped with a primary tessellated mirror dish of 23 m diameter, supported by a structure made mainly of carbon fibre reinforced plastic tubes and aluminum joints. This solution guarantees light weight (around 100 tons), essential for fast repositioning to any position in the sky in <20 seconds. The camera is composed of 1855 PMTs and embeds the control, readout and trigger electronics. The detailed design is now complete and production of the first LST, which will serve as a prototype for the remaining seven, is well underway. In 2016 the first LST will be installed at the Roque de los Muchachos Observatory on the Canary island of La Palma (Spain). In this talk we will outline the technical solutions adopted to fulfill the design requirem...

  15. Latest news from the High Altitude Water Cherenkov Observatory

    Science.gov (United States)

    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.

  16. Kalman filter tracking in a Cherenkov neutrino telescope

    International Nuclear Information System (INIS)

    The reconstruction of tracks in underwater Cherenkov neutrino telescopes is strongly complicated due to large background counting rate originates from 40K beta decay and to the electromagnetic showers accompanying high energy muons together with the effects of light propagation in the water, in particular the photon scattering. These two effects lead to a non-linear problem with a non-Gaussian measurement noise. A method for track reconstruction based on Kalman filter approach in this situation is presented. We use Gaussian Sum Filter algorithm to take into account non-Gaussian process noise. While usual Kalman filter estimators based on linear least-square method are optimal in case all observations are Gaussian distributed, the Gaussian Sum Filter offers a better treatment of non-Gaussian process noise and/or measurement errors when these are modeled by Gaussian mixtures. As an example of the application, the results of muon track reconstruction in NEMO underwater neutrino telescope are presented as well as the comparison of its capability with other standard track reconstruction methods.

  17. Calibration of the Cherenkov Telescope Array using Cosmic Ray Electrons

    CERN Document Server

    Parsons, R D; Schoorlemmer, H

    2016-01-01

    Cosmic ray electrons represent a background for gamma-ray observations with Cherenkov telescopes, initiating air-showers which are difficult to distinguish from photon-initiated showers. This similarity, however, and the presence of cosmic ray electrons in every field observed, makes them potentially very useful for calibration purposes. Here we study the precision with which the relative energy scale and collection area/efficiency for photons can be established using electrons for a major next generation instrument such as CTA. We find that variations in collection efficiency on hour timescales can be corrected to better than 1%. Furthermore, the break in the electron spectrum at ~0.9 TeV can be used to calibrate the energy scale at the 3% level on the same timescale. For observations on the order of hours, statistical errors become negligible below a few TeV and allow for an energy scale cross-check with instruments such as CALET and AMS. Cosmic ray electrons therefore provide a powerful calibration tool, e...

  18. Gravitational Cherenkov losses in theories based on modified Newtonian dynamics.

    Science.gov (United States)

    Milgrom, Mordehai

    2011-03-18

    Survival of high-energy cosmic rays (HECRs) against gravitational Cherenkov losses is shown not to cast strong constraints on modified Newtonian dynamics (MOND) theories that are compatible with general relativity (GR): theories that coincide with GR for accelerations ≫a(0) (a(0) is the MOND constant). The energy-loss rate, E, is many orders smaller than those derived in the literature for theories with no extra scale. Modification to GR, which underlies E, enters only beyond the MOND radius of the particle: r(M)=(Gp/ca(0))(1/2). The spectral cutoff, entering E quadratically, is thus r(M)(-1), not k(dB)=p/ℏ. Thus, E is smaller than published rates, which use k(dB), by a factor ∼(r(M)k(dB))(2)≈10(39)(cp/3×10(11)  Gev)(3). Losses are important only beyond D(loss)≈qℓ(M), where q is a dimensionless factor, and ℓ(M)=c(2)/a(0) is the MOND length, which is ≈2π times the Hubble distance. PMID:21469855

  19. The Instrument Response Function Format for the Cherenkov Telescope Array

    CERN Document Server

    Ward, John E

    2015-01-01

    The Cherenkov Telescope Array (CTA) is a future ground-based observatory (with two locations, in the Northern and Southern Hemispheres) that will be used in the study of the very-high-energy gamma-ray sky. CTA observations will be proposed by external users or initiated by the observatory, with the resulting measurements being processed by the CTA observatory and the reduced data made accessible to the corresponding proposer. Instrument Response Functions (IRFs) will also be provided to convert the quantities measured by the array(s) into relevant science products (i.e. spectra, sky maps, light curves). As the response of the telescopes depend on many correlated observational and physical quantities (e.g. gamma-ray arrival direction, energy, telescope orientation, background light, weather conditions etc.) the CTA IRFs could grow into increasingly larger and larger file sizes, which can become unwieldy or impractical for use in specific observation cases. To this end, a customized IRF format (complying with t...

  20. The Medium Size Telescopes of the Cherenkov Telescope Array

    CERN Document Server

    Pühlhofer, G

    2016-01-01

    The Cherenkov Telescope Array (CTA) is the planned next-generation instrument for ground-based gamma-ray astronomy, covering a photon energy range of ~20 GeV to above 100 TeV. CTA will consist of the order of 100 telescopes of three sizes, installed at two sites in the Northern and Southern Hemisphere. This contribution deals with the 12 meter Medium Size Telescopes (MST) having a single mirror (modified Davies-Cotton, DC) design. In the baseline design of the CTA arrays, 25 MSTs in the South and 15 MSTs in the North provide the necessary sensitivity for CTA in the core energy range of 100 GeV to 10 TeV. DC-MSTs will be equipped with photomultiplier (PMT)-based cameras. Two options are available for these focal plane instruments, that will be provided by the FlashCam and the NectarCAM sub-consortia. In this contribution, a short introduction to the projects and their status is given.

  1. CHERENCUBE: Concept definition and implementation challenges of a Cherenkov-based detector block for PET

    Energy Technology Data Exchange (ETDEWEB)

    Somlai-Schweiger, I., E-mail: ian.somlai@tum.de; Ziegler, S. I. [Nuklearmedizinische Klinik und Poliklinik, Klinikum rechts der Isar, Technische Universität München, Ismaninger Strasse 22, München 81675 (Germany)

    2015-04-15

    Purpose: A new concept for a depth-of-interaction (DOI) capable time-of-flight (TOF) PET detector is defined, based only on the detection of Cherenkov photons. The proposed “CHERENCUBE” consists of a cubic Cherenkov radiator with position-sensitive photodetectors covering each crystal face. By means of the spatial distribution of the detected photons and their time of arrival, the point of interaction of the gamma-ray in the crystal can be determined. This study analyzes through theoretical calculations and Monte Carlo simulations the potential advantages of the concept toward reaching a Cherenkov-only detector for TOF-PET with DOI capability. Furthermore, an algorithm for the DOI estimation is presented and the requirements for a practical implementation of the proposed concept are defined. Methods: The Monte Carlo simulations consisted of a cubic crystal with one photodetector coupled to each one of the faces of the cube. The sensitive area of the detector matched exactly the crystal size, which was varied in 1 mm steps between 1 × 1 × 1 mm{sup 3} and 10 × 10 × 10 mm{sup 3}. For each size, five independent simulations of ten thousand 511 keV gamma-rays were triggered at a fixed distance of 10 mm. The crystal chosen was PbWO{sub 4}. Its scintillation properties were simulated, but only Cherenkov photons were analyzed. Photodetectors were simulated having perfect photodetection efficiency and infinite time resolution. For every generated particle, the analysis considered its creation process, parent and daughter particles, energy, origin coordinates, trajectory, and time and position of detection. The DOI determination is based on the distribution of the emission time of all photons per event. These values are calculated as a function of the coordinates of detection and origin for every photon. The common origin is estimated by finding the distribution with the most similar emission time-points. Results: Detection efficiency increases with crystal size from

  2. A facility to evaluate the focusing performance of mirrors for Cherenkov Telescopes

    CERN Document Server

    Canestrari, Rodolfo; Bonnoli, Giacomo; Farisato, Giancarlo; Lessio, Luigi; Rodeghiero, Gabriele; Spiga, Rossella; Toso, Giorgio; Pareschi, Giovanni

    2015-01-01

    With the advent of the imaging atmospheric Cherenkov technique in late 1980's, ground-based observations of Very High-Energy gamma rays came into reality. Since the first source detected at TeV energies in 1989 by Whipple, the number of high energy gamma-ray sources has rapidly grown up to more than 150 thanks to the second generation experiments like MAGIC, H.E.S.S. and VERITAS. The Cherenkov Telescope Array observatory is the next generation of Imaging Atmospheric Cherenkov Telescopes, with at least 10 times higher sensitivity than current instruments. Cherenkov Telescopes have to be 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 Cherenkov telescopes operate (in open air without dome protection). For this purpose a new facility for the characterization of mi...

  3. Status and updates from the High Altitude Water Cherenkov (HAWC) Observatory

    Energy Technology Data Exchange (ETDEWEB)

    Baughman, B.M., E-mail: bbaugh@umdgrb.umd.edu

    2013-06-15

    The High Altitude Water Cherenkov Observatory (HAWC) is currently being deployed on the slopes of Volcan Sierra Negra, Puebla, Mexico. The HAWC observatory will consist of 300 Water Cherenkov Detectors totaling approximately 22,000 m{sup 2} of instrumented area. The water Cherenkov technique allows HAWC to have a nearly 100% duty cycle and large field of view, making the HAWC observatory an ideal instrument for the study of transient phenomena. With its large effective area, excellent angular and energy resolutions, and efficient gamma-hadron separation, HAWC will survey the TeV gamma ray sky, measure spectra of galactic sources from 1 TeV to beyond 100 TeV, and map galactic diffuse gamma ray emission. The science goals and performance of the HAWC observatory as well as how it will complement contemporaneous space and ground-based detectors will be presented.

  4. Lateral density and arrival time distributions of Cherenkov photons in extensive air showers: a simulation study

    CERN Document Server

    Hazarika, P; Chitnis, V R; Acharya, B S; Das, G S; Singh, B B; Britto, R

    2014-01-01

    We have investigated some features of the density and arrival time distributions of Cherenkov photons in extensive air showers using different high and low energy hadronic interaction models available in the CORSIKA simulation package. We have found that, for all primary particles, their energies and hadronic interaction model combinations, the density distribution patterns of Cherenkov photons follow the negative exponential function with different coefficients and slopes depending on the type of primary particle, its energy and the type of model combination. Whereas the arrival time distribution patterns of Cherenkov photons follow the function of the form $t (r) = t_{0}e^{\\Gamma/r^{\\lambda}}$, with different values of the function parameters. Flatness of the density distribution increases with decreasing energy and increasing mass of the primary particle. The shift from the spherical shape of the arrival time distribution near the shower core increases with increasing mass of the low energy primary particl...

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

    Science.gov (United States)

    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.

  6. Measurements of K/Π ratio in cosmic radiation

    International Nuclear Information System (INIS)

    Measurements of k/Π ratio in cosmic radiation by its half lives and its fluxes, were carried out. The kaon flux was obtained using the Cherenkov detector, and for pion flux scintillation detectors were used. The final results of K/Π ratio ∼ 0.2 was obtained. (M.C.K.)

  7. Layout design studies for medium-sized telescopes within the Cherenkov Telescope Array

    CERN Document Server

    Hassan, T; Nieto, D; Wood, M

    2015-01-01

    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. In this study we explore how the medium-sized telescopes layout design and composition impacts the overall CTA performance by analyzing Monte Carlo simulations including Davies-Cotton and Schwarzschild-Couder medium-sized telescopes.

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

    Science.gov (United States)

    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.

  9. Prototyping the graphical user interface for the operator of the Cherenkov Telescope Array

    CERN Document Server

    Sadeh, Iftach; Schwarz, Joseph; Pietriga, Emmanuel

    2016-01-01

    The Cherenkov Telescope Array (CTA) is a planned gamma-ray observatory. CTA will incorporate about 100 imaging atmospheric Cherenkov telescopes (IACTs) at a Southern site, and about 20 in the North. Previous IACT experiments have used up to five telescopes. Subsequently, the design of a graphical user interface (GUI) for the operator of CTA involves new challenges. We present a GUI prototype, the concept for which is being developed in collaboration with experts from the field of Human-Computer Interaction. The prototype is based on Web technology; it incorporates a Python web server, Web Sockets and graphics generated with the d3.js Javascript library.

  10. A G-APD based Camera for Imaging Atmospheric Cherenkov Telescopes

    Energy Technology Data Exchange (ETDEWEB)

    Anderhub, H. [Eidgenoessische Technische Hochschule Zuerich, 8093 Zuerich (Switzerland); Backes, M. [Technische Universitaet Dortmund, 44221 Dortmund (Germany); Biland, A.; Boller, A.; Braun, I. [Eidgenoessische Technische Hochschule Zuerich, 8093 Zuerich (Switzerland); Bretz, T. [Ecole Polytechnique Federale de Lausanne, 1015 Lausanne (Switzerland); Commichau, S.; Commichau, V.; Dorner, D.; Gendotti, A. [Eidgenoessische Technische Hochschule Zuerich, 8093 Zuerich (Switzerland); Grimm, O., E-mail: oliver.grimm@phys.ethz.c [Eidgenoessische Technische Hochschule Zuerich, 8093 Zuerich (Switzerland); Gunten, H. von; Hildebrand, D.; Horisberger, U. [Eidgenoessische Technische Hochschule Zuerich, 8093 Zuerich (Switzerland); Koehne, J.-H. [Technische Universitaet Dortmund, 44221 Dortmund (Germany); Kraehenbuehl, T.; Kranich, D.; Lorenz, E.; Lustermann, W. [Eidgenoessische Technische Hochschule Zuerich, 8093 Zuerich (Switzerland); Mannheim, K. [Universitaet Wuerzburg, 97074 Wuerzburg (Germany)

    2011-02-01

    Imaging Atmospheric Cherenkov Telescopes (IACT) for Gamma-ray astronomy are presently using photomultiplier tubes as photo sensors. Geiger-mode avalanche photodiodes (G-APD) promise an improvement in sensitivity and, important for this application, ease of construction, operation and ruggedness. G-APDs have proven many of their features in the laboratory, but a qualified assessment of their performance in an IACT camera is best undertaken with a prototype. This paper describes the design and construction of a full-scale camera based on G-APDs realized within the FACT project (First G-APD Cherenkov Telescope).

  11. Cherenkov and Fano effects at the origin of asymmetric vector mesons in nuclear media

    CERN Document Server

    Dremin, I M

    2015-01-01

    It is argued that the experimentally observed phenomenon of asymmetric vector mesons produced in nuclear media during high energy nucleus-nucleus collisions can be explained as Cherenkov and Fano effects. The mass distributions of lepton pairs created at meson decays decline from the traditional Breit-Wigner shape in the low-mass wing of the resonance. That is explained by the positive real part of the amplitude in this wing for classic Cherenkov treatment and further detalized in quantum mechanics as the interference of direct and continuum states in Fano effect. The corresponding parameters are found from the comparison with rho-meson data and admit reasonable explanation.

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

    International Nuclear Information System (INIS)

    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

  13. SST-GATE: A dual mirror telescope for the Cherenkov Telescope Array

    OpenAIRE

    Zech, A.; Amans, J.-P.; Blake, S; Boisson, C.; Costille, C.; De-Frondat, F.; Dournaux, J. -L.; Dumas, D.; Fasola, G.; T. Greenshaw; Hervet, O.; Huet, J. -M.; Laporte, P.; Rulten, C.; Savoie, D.

    2013-01-01

    The Cherenkov Telescope Array (CTA) will be the world's first open observatory for very high energy gamma-rays. Around a hundred telescopes of different sizes will be used to detect the Cherenkov light that results from gamma-ray induced air showers in the atmosphere. Amongst them, a large number of Small Size Telescopes (SST), with a diameter of about 4 m, will assure an unprecedented coverage of the high energy end of the electromagnetic spectrum (above ~1TeV to beyond 100 TeV) and will ope...

  14. Measuring the Attenuation Length of Water in the CHIPS-M Water Cherenkov Detector

    CERN Document Server

    Amat, F; Bryant, J; Carroll, T J; Germani, S; Joyce, T; Kreisten, B; Marshak, M; Meier, J; Nelson, J; Perch, A; Pfuzner, M; De Rijck, S; Salazar, R; Thomas, J; Trokan-Tenorio, J; Vahle, P; Wade, R; Whitehead, L; Whitney, M

    2016-01-01

    The water at the proposed site of the CHIPS water Cherenkov detector has been studied to measure its attenuation length for Cherenkov light as a function of filtering time. A scaled model of the CHIPS detector filled with water from the Wentworth 2W pit, proposed site of the CHIPS deployment, in conjunction with a 3.2\\unit{m} vertical column filled with this water, was used to study the transmission of 405nm laser light. Results consistent with attenuation lengths of up to 100m were observed for this wavelength with filtration and UV sterilization alone.

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

    Science.gov (United States)

    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.

  16. Design of a 7m Davies-Cotton Cherenkov telescope mount for the high energy section of the Cherenkov Telescope Array

    CERN Document Server

    Rovero, A C; Vallejo, G; Supanitsky, A D; Actis, M; Botani, A; Ochoa, I; Hughes, G

    2013-01-01

    The Cherenkov Telescope Array is the next generation ground-based observatory for the study of very-high-energy gamma-rays. It will provide an order of magnitude more sensitivity and greater angular resolution than present systems as well as an increased energy range (20 GeV to 300 TeV). For the high energy portion of this range, a relatively large area has to be covered by the array. For this, the construction of ~7 m diameter Cherenkov telescopes is an option under study. We have proposed an innovative design of a Davies-Cotton mount for such a telescope, within Cherenkov Telescope Array specifications, and evaluated its mechanical and optical performance. The mount is a reticulated-type structure with steel tubes and tensioned wires, designed in three main parts to be assembled on site. In this work we show the structural characteristics of the mount and the optical aberrations at the focal plane for three options of mirror facet size caused by mount deformations due to wind and gravity.

  17. An analog neural network hardware solution to a Cherenkov ring imaging particle identifier

    International Nuclear Information System (INIS)

    This paper describes the implementation of an analog neural network chip (Intel 80170NX) to the pad readout of a Cherenkov ring imaging detector system. A similar system has previously been tested in software in order to separate proton and pion events. The architecture, training and testing in analog hardware is described. (orig.)

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

    Science.gov (United States)

    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.

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

    CERN Document Server

    Krizmanic, John F

    2011-01-01

    Future space-based experiments, such as OWL and JEM-EUSO, view large atmospheric and terrestrial neutrino targets. With energy thresholds slightly above 10^19 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 nu_tau-induced Cherenkov airshower signal at above the OWL Cherenkov energy threshold of ~10^16.5 eV for limb-viewed events. Furthermore, the neutri...

  20. Gas breakdown limit and maximum acceleration gradient for inverse Cherenkov laser accelerator

    CERN Document Server

    Liu, Y; Cline, D

    1999-01-01

    Laser intensity thresholds for CO sub 2 laser-induced gas breakdown, such as tunneling, multiphoton, and cascade ionization have been estimated for the inverse Cherenkov accelerator experiment at the Brookhaven Accelerator Test Facility. The gas breakdown is dominated by cascade ionization and the maximum acceleration gradient is up to 300 MeV/m for a 3 ps CO sub 2 laser.

  1. Search for long-lived heavy charged particles using a ring imaging Cherenkov technique at LHCb

    NARCIS (Netherlands)

    Aaij, R.; Adeva, B.; Adinolfi, M.; Affolder, A.; Ajaltouni, Z.; Akar, S.; Albrecht, J.; Alessio, F.; Alexander, M.; Ali, S.; Alkhazov, G.; Cartelle, P. Alvarez; Alves, A. A.; Amato, S.; Amerio, S.; Amhis, Y.; An, L.; Anderlini, L.; Anderson, J.; Andreotti, M.; Andrews, J. E.; Appleby, R. B.; Gutierrez, O. Aquines; 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.; Perez, D. Campora; Capriotti, L.; Carbone, A.; Carboni, G.; Cardinale, R.; Cardini, A.; Carniti, P.; Carson, L.; Carvalho Akiba, K.; Casanova Mohr, R.; Casse, G.; Cassina, L.; Garcia, L. Castillo; Cattaneo, M.; Cauet, Ch.; Cavallero, G.; Cenci, R.; Charles, M.; Charpentier, Ph.; Chefdeville, M.; Chen, S.; Cheung, S. F.; Chiapolini, N.; Chrzaszcz, M.; Vidal, X. Cid; 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.; CruzTorres, 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.; Deleage, N.; Derkach, D.; Deschamps, O.; Dettori, F.; Dey, B.; Di Canto, A.; Di Ruscio, F.; Dijkstra, H.; Donleavy, S.; Dordei, F.; Dorigo, M.; Dosil Suarez, 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.; ElRifai, I.; Elsasser, Ch.; Ely, S.; Esen, S.; Evans, H. M.; Evans, T.; Falabella, A.; Faerber, 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.; Torreira, A. Gallas; Galli, D.; Gallorini, S.; Gambetta, S.; Gandelman, M.; Gandini, P.; Gao, Y.; Garcia Pardinas, J.; Garofoli, J.; Tico, J. Garra; 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.; Giani, S.; Gibson, V.; Giubega, L.; Gligorov, V. V.; Goebel, C.; Golubkov, D.; Golutvin, A.; Gomes, A.; Gotti, C.; Gandara, M. Grabalosa; Diaz, R. Graciani; Cardoso, L. A. Granado; Grauges, E.; Graverini, E.; Graziani, G.; Grecu, A.; Greening, E.; Gregson, S.; Griffith, P.; Grillo, L.; Gruenberg, 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.

    2015-01-01

    A search is performed for heavy long-lived charged particles using 3.0 fb(-1) of proton-proton collisions collected at root 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

  2. Electrostatic design of the barrel CRID (Cherenkov Ring Imaging Detector) and associated measurements

    Energy Technology Data Exchange (ETDEWEB)

    Abe, K.; Hasegawa, K.; Suekane, F.; Yuta, H. (Tohoku Univ., Sendai (Japan). Dept. of Physics); Antilogus, P.; Aston, D.; Bienz, T.; Bird, F.; Dunwoodie, W.; Hallewell, G.; Kawahara, H.; Kwon, Y.; Leith, D.W.G.S.; Muller, D.; Nagamine, T.; Pavel, T.; Ratcliff, B.; Rensing, P.; Schultz, D.; Shapiro, S.; Simopoulos, C.; Solodov, E.; Toge, N.; Va' Vra, J. Williams, H. (Stanford Linear Accelerator Center, Menlo Park, CA (US

    1990-04-01

    We report on the electrostatic design and related measurements of the barrel Cherenkov Ring Imaging Detector for the Stanford Large Detector experiment at the Stanford Linear Accelerator Center Linear Collider. We include test results of photon feedback in TMAE-laden gas, distortion measurements in the drift boxes and corona measurements. 13 refs., 21 figs.

  3. Recent modelling studies for analysing the partial‑defect detection capability of the Digital Cherenkov Viewing Device

    International Nuclear Information System (INIS)

    Strong sources of radioactivity, such as spent nuclear fuel stored in water pools, give rise to Cherenkov light. This light originates from particles, in this case electrons released from gamma‑ray interactions, which travel faster than the speed of light in the water. In nuclear safeguards, detection of the Cherenkov light intensity is used as a means for verifying gross and partial defect of irradiated fuel assemblies in wet storage. For spent nuclear fuel, the magnitude of the Cherenkov light emission depends on the initial fuel enrichment (IE), the power history (in particular the total fuel burnup (BU)) and the cooling time (CT). This paper presents recent results on the expected Cherenkov light emission intensity obtained from modelling a full 8x8 BWR fuel assembly with varying values of IE, BU and CT. These results are part of a larger effort to also investigate the Cherenkov light emission for fuels with varying irradiation history and other fuel geometries in order to increase the capability to predict the light intensity and thus lower the detection limits for the Digital Cherenkov Viewing Device (DCVD). The results show that there is a strong dependence of the Cherenkov light intensity on BU and CT, in accordance with previous studies. However, the dependences demonstrated previously are not fully repeated; the current study indicates a less steep decrease of the intensity with increasing CT. Accordingly, it is suggested to perform dedicated experimental studies on fuel with different BU and CT to resolve the differences and to enhance future predictive capability. In addition to this, the dependence of the Cherenkov light intensity on the IE has been investigated. Furthermore, the modelling of the Cherenkov light emission has been extended to CTs shorter than one year. The results indicate that high‑accuracy predictions for short‑cooled fuel may require more detailed information on the irradiation history.

  4. Coherent radiation of relativistic electrons in wire metamaterial

    Science.gov (United States)

    Soboleva, V.; Naumenko, G.; Bleko, V.

    2016-07-01

    We present in this work the experimental investigation of the interaction of relativistic electron field with wire metamaterial. The measurements of the spectral-angular characteristics of coherent radiation were done in millimeter wavelength region in far-field zone at the relativistic electron beam with energy of 6 MeV. Used target represent the right triangular prism that consist of periodic placed copper wires. We showed that bunched electron beam passing near wire metamaterial prism generates coherent Cherenkov radiation. Spectral angular characteristics of radiation from the wire target were compared with the characteristics of Cherenkov radiation generated in similar experimental conditions in a dielectric target (Teflon prism) that has the same form and sizes.

  5. The CLEO-III Ring Imaging Cherenkov Detector

    CERN Document Server

    Mountain, R J; Artuso, M; Ayad, R; Azfar, F; Coan, T E; Efimov, A; Fadeev, V; Kopp, S E; Kubota, Y; Lipeles, E; Majumder, G; Schuh, S; Skwarnicki, T; Smith, A; Staeck, J; Stone, S; Viehhauser, G; Volobuev, I P

    1999-01-01

    The CLEO-III Detector upgrade for charged particle identification is discussed. The RICH design uses solid LiF crystal radiators coupled with multi-wire chamber photon detectors, using TEA as the photosensor, and low-noise Viking readout electronics. Results from our beam test at Fermilab are presented.

  6. The endpoint formalism for the calculation of electromagnetic radiation and its applications in astroparticle physics

    CERN Document Server

    Huege, Tim; Falcke, Heino; Ludwig, Marianne

    2011-01-01

    We present the "endpoint" formalism for the calculation of electromagnetic radiation and illustrate its applications in astroparticle physics. We use the formalism to explain why the coherent radiation from the Askaryan effect is not in general Cherenkov radiation, as the emission directly results from the time-variation of the net charge in the particle shower. Secondly, we illustrate how the formalism has been applied in the air shower radio emission code REAS3 to unify the microscopic and macroscopic views of radio emission from extensive air showers. Indeed, the formalism is completely universal and particularly well-suited for implementation in Monte Carlo codes in the time- and frequency-domains. It easily reproduces well-known "classical mechanisms" such as synchrotron radiation, Vavilov-Cherenkov radiation and transition radiation in the adequate limits, but has the advantage that it continues to work in realistic, complex situations, where the "classical mechanisms" tend to no longer apply and adheri...

  7. The physics of charged particle identification: de/dx Cherenkov and transition radiation

    International Nuclear Information System (INIS)

    The analysis of most High Energy Physics experiments requires a knowledge of the 4-momenta, (p,E) of the secondary particles. The 3-momenta, p, are usually obtained by measuring the deflection of the trajectory of each of the particles in a magnetic field. A further measurement, be it of mass, energy of velocity, is needed to determine the fourth component of the 4-momentum, E, and fix a value for the mass M. Since M uniquely (for charged particles) identifies the internal quantum numbers, this measurement is generally referred to as ''particle identification''. At low energies particle identification has traditionally been achieved by total absorption calorimetry, by time-of-flight measurement or by simple dE/dx measurements. Calorimetry becomes more difficult at higher energies, as the number of interaction lengths of absorber needed to contain the showers completely becomes large. More seriously, the energy resolution, ΔE/E, required to distinguish different masses varies as E/sup -2/, while the resolution achievable varies as E/sup -1/2/. Time-of-flight measurements yield the velocity of the particles over a given distance

  8. Divergent pointing with the Cherenkov Telescope Array for surveys and beyond

    CERN Document Server

    ,

    2015-01-01

    The galactic and extragalactic surveys are two of the main proposed legacy projects of the Cherenkov Telescope Array (CTA), providing an unbiased view of the Universe at energies above tens of GeV. Considering Cherenkov telescopes' limited field of view ($<10^\\circ$), the time needed for those projects is large. The many telescopes of CTA will allow taking full advantage of new pointing modes in which telescopes point slightly offset from one another. This divergent pointing mode leads to an increase of the array field of view ($\\sim 14^\\circ$ or larger) with competitive performance compared to normal pointing. We present here a study of the performance of the divergent pointing for different array configurations and number of telescopes. We briefly discuss the prospect of using divergent pointing for surveys.

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

    Science.gov (United States)

    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.

  10. Space-charge effects and gain in Cherenkov free-electron lasers

    International Nuclear Information System (INIS)

    This paper presents a quantum mechanical treatment to study the growth rate characteristics of Cherenkov free-electron laser. For this purpose, we basically use the single-particle model in which the dynamics of a single electron in the presence of the laser field is analyzed. The inclusions of the space-charge (collective) effects are considered by taking into account the static electric field of neighboring electrons in the dynamics formulations. An analytical expression for the gain per pass in the Cherenkov laser is derived. It is shown that the space-charge effects depend mainly on the operating wavelength, the electron density, and the electron beam neutralization due to the possible presence of positive ions. We discuss the validity boundaries of the interaction mode evolved from the single-particle regime to the collective regime. Using quantum mechanical concepts, we finally present a formula for calculating the inclusion of the spontaneous emission power

  11. Detection of Cherenkov light from air showers with Geiger-APDs

    CERN Document Server

    Otte, A N; Biland, A; Göbel, F; Lorenz, E; Pauss, F; Renker, D; Röser, U; Schweizer, T

    2007-01-01

    We have detected Cherenkov light from air showers with Geiger-mode APDs (G-APDs). G-APDs are novel semiconductor photon-detectors, which offer several advantages compared to conventional photomultiplier tubes in the field of ground-based gamma-ray astronomy. In a field test with the MAGIC telescope we have tested the efficiency of a G-APD / light catcher setup to detect Cherenkov light from air showers. We estimate a detection efficiency, which is 60% higher than the efficiency of a MAGIC camera pixel. Ambient temperature dark count rates of the tested G-APDs are below the rates of the night sky light background. According to these recent tests G-APDs promise a major progress in ground-based gamma-ray astronomy.

  12. Schwarzschild-Couder telescope for the Cherenkov Telescope Array: Development of the Optical System

    CERN Document Server

    Rousselle, Julien; Errando, Manel; Humensky, Brian; Mukherjee, Reshmi; Nieto, Daniel; Okumura, Akira; Vassiliev, Vladimir

    2013-01-01

    The CTA (Cherenkov Telescope Array) is the next generation ground-based experiment for very high-energy (VHE) gamma-ray observations. It will integrate several tens of imaging atmospheric Cherenkov telescopes (IACTs) with different apertures into a single astronomical instrument. The US part of the CTA collaboration has proposed and is developing a novel IACT design with a Schwarzschild-Couder (SC) aplanatic two mirror optical system. In comparison with the traditional single mirror Davies-Cotton IACT the SC telescope, by design, can accommodate a wide field-of-view, with significantly improved imaging resolution. In addition, the reduced plate scale of an SC telescope makes it compatible with highly integrated cameras assembled from silicon photo multipliers. In this submission we report on the status of the development of the SC optical system, which is part of the effort to construct a full-scale prototype telescope of this type at the Fred Lawrence Whipple Observatory in southern Arizona.

  13. Developments for coating, testing, and aligning Cherenkov Telescope Array mirrors in T\\"ubingen

    CERN Document Server

    Bonardi, A; Kendziorra, E; Pühlhofer, G

    2013-01-01

    The Cherenkov Telescope Array (CTA) is the next generation very-high energy gamma-ray air-shower Cherenkov observatory. CTA will consist of many segmented-mirror telescopes of three different diameters, placed in two arrays, one in the Northern hemisphere and one in the South, thus covering the whole sky. The total number of mirror tiles will be of the order of 10000, corresponding to a reflective area of ~10^4 m^2. The Institute for Astronomy and Astrophysics in T\\"ubingen is developing procedures to coat glass-substrate-based mirror tiles, is participating to the CTA mirror prototype testing, and is prototyping Active Mirror Control alignment mechanics, electronics and software. We will present the current status of our work and plans for future developments.

  14. Monte Carlo Studies of medium-size telescope designs for the Cherenkov Telescope Array

    CERN Document Server

    Wood, M; Dumm, J; Funk, S

    2015-01-01

    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 repre...

  15. CHerenkov detectors In mine PitS (CHIPS) Letter of Intent to FNAL

    CERN Document Server

    Adamson, P; Davies, G S; Evans, J J; Guzowski, P; Habig, A; Hartnell, J; Holin, A; Huang, J; Kreymer, A; Kordosky, M; Lang, K; Marshak, M L; Mehdiyev, R; Meier, J; Miller, W; Naples, D; Nelson, J K; Nichol, R J; Patterson, R B; Perch, A; Pfutzner, M; Proga, M; Radovic, A; Sanchez, M C; Schreiner, S; Soldner-Rembold, S; Sousa, A; Thomas, J; Vahle, P; Wendt, C; Whitehead, L H; Wojcicki, S

    2013-01-01

    This Letter of Intent outlines a proposal to build a large, yet cost-effective, 100 kton fiducial mass water Cherenkov detector that will initially run in the NuMI beam line. The CHIPS detector (CHerenkov detector In Mine PitS) will be deployed in a flooded mine pit, removing the necessity and expense of a substantial external structure capable of supporting a large detector mass. There are a number of mine pits in northern Minnesota along the NuMI beam that could be used to deploy such a detector. In particular, the Wentworth Pit 2W is at the ideal off-axis angle to contribute to the measurement of the CP violating phase. The detector is designed so that it can be moved to a mine pit in the LBNE beam line once that becomes operational.

  16. Towards a full Atmospheric Calibration system for the Cherenkov Telescope Array

    CERN Document Server

    Doro, M; Blanch, O; Font, LL; Garrido, D; Lopez-Oramas, A

    2013-01-01

    The current generation of Cherenkov telescopes is mainly limited in their gamma-ray energy and flux reconstruction by uncertainties in the determination of atmospheric parameters. The Cherenkov Telescope Array (CTA) aims to provide high-precision data extending the duty cycle as much as possible. To reach this goal, it is necessary to continuously and precisely monitor the atmosphere by means of remote-sensing devices, which are able to provide altitude-resolved and wavelength-dependent extinction factors, sensitive up to the tropopause and higher. Raman LIDARs are currently the best suited technology to achieve this goal with one single instrument. However, the synergy with other instruments like radiometers, solar and stellar photometers, all-sky cameras, and possibly radio-sondes is desirable in order to provide more precise and accurate results, and allows for weather forecasts and now-casts. In this contribution, we will discuss the need and features of such multifaceted atmospheric calibration systems.

  17. First ground based measurement of atmospheric Cherenkov light from cosmic rays

    CERN Document Server

    Aharonian, F A; Bazer-Bachi, A R; Beilicke, M; Benbow, W; Berge, D; Bernlöhr, K; Boisson, C; Bolz, O; Borrel, V; Braun, I; Brion, E; Brown, A M; Buhler, R; Büsching, I; Carrigan, S; Chadwick, P M; Chounet, L M; Coignet, G; Cornils, R; Costamante, L; Degrange, B; Dickinson, H J; Djannati-Atai, A; O'Connor-Drury, L; Dubus, G; Egberts, K; Emmanoulopoulos, D; Espigat, P; Feinstein, F; Ferrero, E; Fiasson, A; Fontaine, G; Funk, Seb; Funk, S; Fussling, M; Gallant, Y A; Giebels, B; Glicenstein, J F; Glück, B; Goret, P; Hadjichristidis, C; Hauser, D; Hauser, M; Heinzelmann, G; Henri, G; Hermann, G; Hinton, J A; Hoffmann, A; Hofmann, W; Holleran, M; Hoppe, S; Horns, D; Jacholkowska, A; De Jager, O C; Kendziorra, E; Kerschhaggl, M; Khelifi, B; Komin, Nu; Konopelko, A; Kosack, K; Lamanna, G; Latham, I J; Le Gallou, R; Lemiere, A; Lemoine-Goumard, M; Lohse, T; Martin, J M; Martineau-Huynh, O; Marcowith, A; Masterson, C; Maurin, G; McComb, T J L; Moulin, E; De Naurois, Mathieu; Nedbal, D; Nolan, S J; Noutsos, A; Olive, J P; Orford, K J; Osborne, J L; Panter, M; Pelletier, G; Pita, S; Pühlhofer, G; Punch, M; Ranchon, S; Raubenheimer, B C; Raue, M; Rayner, S M; Reimer, A; Ripken, J; Rob, L; Rolland, L; Rosier-Lees, S; Rowell, G; Sahakian, V V; Santangelo, A; Sauge, L; Schlenker, S; Schlickeiser, R; Schroder, R; Schwanke, U; Schwarzburg, S; Schwemmer, S; Shalchi, A; Sol, H; Spangler, D; Spanier, F; Steenkamp, R; Stegmann, C; Superina, G; Tam, P H; Tavernet, J P; Terrier, R; Tluczykont, M; Van Eldik, C; Vasileiadis, G; Venter, C; Vialle, J P; Vincent, P; Völk, H J; Wagner, S J; Ward, M

    2007-01-01

    A recently proposed novel technique for the detection of cosmic rays with arrays of Imaging Atmospheric Cherenkov Telescopes is applied to data from the High Energy Stereoscopic System (H.E.S.S.). The method relies on the ground based detection of Cherenkov light emitted from the primary particle prior to its first interaction in the atmosphere. The charge of the primary particle (Z) can be estimated from the intensity of this light, since it is proportional to Z$^2$. Using H.E.S.S. data, an energy spectrum for cosmic-ray iron nuclei in the energy range 13--200 TeV is derived. The reconstructed spectrum is consistent with previous direct measurements and is one of the most precise so far in this energy range.

  18. A template method for measuring the iron spectrum in cosmic rays with Cherenkov telescopes

    CERN Document Server

    ,

    2015-01-01

    Understanding the sources, acceleration mechanisms, and propagation of cosmic rays is an active area of research in astro-particle physics. Measuring the spectrum and elemental composition of cosmic rays on earth can help solve this question. IACTs, while mainly used for $\\gamma$-ray astronomy and indirect searches for dark matter, can make an important contribution here. In particular, they are able to distinguish heavy nuclei in cosmic rays from protons and lighter nuclei by exploiting the direct Cherenkov light emitted by charged particles high in the atmosphere. In this paper, a method to reconstruct relevant properties of primary cosmic ray particles from the Cherenkov light emitted by the primary particles and the air showers induced by them will be presented.

  19. Recent developments for the testing of Cherenkov Telescope Array mirrors and actuators in T\\"ubingen

    CERN Document Server

    ,

    2015-01-01

    The Cherenkov Telescope Array (CTA) is the next generation Cherenkov telescope facility. It will consist of a large number of segmented-mirror telescopes of three different diameters, placed in two locations, one in the northern and one in the southern hemisphere, thus covering the whole sky. The total number of mirror tiles will be on the order of 10,000, corresponding to a reflective area of ~10^4 m^2. The Institute for Astronomy and Astrophysics in T\\"ubingen (IAAT) is currently developing mirror control alignment mechanics, electronics, and software optimized for the medium sized telescopes. In addition, IAAT is participating in the CTA mirror prototype testing. In this paper we present the status of the current developments, the main results of recent tests, and plans for the production phase of the mirror control system. We also briefly present the T\\"ubingen facility for mirror testing.

  20. Status of the Schwarzchild-Couder Medium-Sized Telescope for the Cherenkov Telescope Array

    CERN Document Server

    Benbow, W

    2016-01-01

    The Cherenkov Telescope Array (CTA) is planned to be the next-generation very-high-energy (VHE; E > 100 GeV) gamma-ray observatory. It is anticipated that CTA will improve upon the sensitivity of the current generation of VHE experiments, such as VERITAS, HESS and MAGIC, by an order of magnitude. CTA is planned to consist of two graded arrays of Cherenkov telescopes with three primary-mirror sizes. A proof-of-concept telescope, based on the dual-mirror Schwarzchild-Couder design, is being constructed on the VERITAS site at the F.L. Whipple Observatory in southern Arizona, USA, and is a candidate design for the medium-sized telescopes. The construction of the telescope will be completed in early 2017, and the status of this project is presented here.

  1. The ASTRI project within Cherenkov Telescope Array: data analysis and archiving

    Science.gov (United States)

    Antonelli, Lucio Angelo; Bastieri, Denis; Capalbi, Milvia; Carosi, Alessandro; Catalano, Osvaldo; Di Paola, Andrea; Gallozzi, Stefano; Lombardi, Saverio; Lucarelli, Fabrizio; Perri, Matteo; Testa, Vincenzo

    2014-07-01

    ASTRI is the flagship project of INAF (Italian National Institute for Astrophysics) mainly devoted to the development of Cherenkov small-size dual-mirror telescopes (SST-2M) in the framework of the international Cherenkov Telescope Array (CTA) Project. ASTRI SST-2M is an end-to-end prototype including scientific and technical operations as well as the related data analysis and archiving activities. We present here the ASTRI data handling and archiving system: it is responsible for both the on-site and off-site data processing and archiving. All the scientific, calibration, and engineering ASTRI data will be stored and organized in dedicated archives aimed to provide access to both the monitoring and data analysis systems.

  2. Observations Of The Egret Blazar W Comae With The Solar Tower Atmospheric Cherenkov Effect Experiment

    CERN Document Server

    Scalzo, R A

    2004-01-01

    The Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) is a wavefront-sampling atmospheric Cherenkov telescope which uses an array of solar heliostat mirrors as its primary optic. STACEE is designed to detect air showers from astrophysical gamma rays with energies between 50 and 250 GeV. Recent observations of the BL Lac object W Comae (ON+231), made in the spring of 2003 using STACEE, detect no significant gamma ray emission. The implications of this null result for the composition of the relativistic jet in W Comae is discussed, examining both leptonic and hadronic jet models from the literature. The 95% confidence level upper limit on the flux ranges from 1.5–3.5 × 10−10 cm−2 s−1 above 100 GeV for the leptonic models, and from 0.5–1.1 × 10−10 cm−2 s−1 above 150 GeV for the hadronic models.

  3. SiPM and front-end electronics development for Cherenkov light detection

    CERN Document Server

    Ambrosi, G; Bissaldi, E; Ferri, A; Giordano, F; Gola, A; Ionica, M; Paoletti, R; Piemonte, C; Paternoster, G; Simone, D; Vagelli, V; Zappala, G; Zorzi, N

    2015-01-01

    The Italian Institute of Nuclear Physics (INFN) is involved in the development of a demonstrator for a SiPM-based camera for the Cherenkov Telescope Array (CTA) experiment, with a pixel size of 6$\\times$6 mm$^2$. The camera houses about two thousands electronics channels and is both light and compact. In this framework, a R&D program for the development of SiPMs suitable for Cherenkov light detection (so called NUV SiPMs) is ongoing. Different photosensors have been produced at Fondazione Bruno Kessler (FBK), with different micro-cell dimensions and fill factors, in different geometrical arrangements. At the same time, INFN is developing front-end electronics based on the waveform sampling technique optimized for the new NUV SiPM. Measurements on 1$\\times$1 mm$^2$, 3$\\times$3 mm$^2$, and 6$\\times$6 mm$^2$ NUV SiPMs coupled to the front-end electronics are presented

  4. The image camera of the 17 m diameter air Cherenkov telescope MAGIC

    CERN Document Server

    Ostankov, A P

    2001-01-01

    The image camera of the 17 m diameter MAGIC telescope, an air Cherenkov telescope currently under construction to be installed at the Canary island La Palma, is described. The main goal of the experiment is to cover the unexplored energy window from approx 10 to approx 300 GeV in gamma-ray astrophysics. In its first phase with a classical PMT camera the MAGIC telescope is expected to reach an energy threshold of approx 30 GeV. The operational conditions, the special characteristics of the developed PMTs and their use with light concentrators, the fast signal transfer scheme using analog optical links, the trigger and DAQ organization as well as image reconstruction strategy are described. The different paths being explored towards future camera improvements, in particular the constraints in using silicon avalanche photodiodes and GaAsP hybrid photodetectors in air Cherenkov telescopes are discussed.

  5. Status of the technologies for the production of the Cherenkov Telescope Array (CTA) mirrors

    CERN Document Server

    Pareschi, G; Baba, H; Bähr, J; Bonardi, A; Bonnoli, G; Brun, P; Canestrari, R; Chadwick, P; Chikawa, M; Carton, P -H; de Souza, V; Dipold, J; Doro, M; Durand, D; Dyrda, M; Förster, A; Garczarczyk, M; Giro, E; Glicenstein, J -F; Hanabata, Y; Hayashida, M; Hrabovski, M; Jeanney, C; Kagaya, M; Katagiri, H; Lessio, L; Mandat, D; Mariotti, M; Medina, C; Michałowski, J; Micolon, P; Nakajima, D; Niemiec, J; Nozato, A; Palatka, M; Pech, M; Peyaud, B; Pühlhofer, G; Rataj, M; Rodeghiero, G; Rojas, G; Rousselle, J; Sakonaka, R; Schovanek, P; Seweryn, K; Schultz, C; Shu, S; Stinzing, F; Stodulski, M; Teshima, M; Travniczek, P; van Eldik, C; Vassiliev, V; Wiśniewski, Ł; Wörnlein, A; Yoshida, T

    2013-01-01

    The Cherenkov Telescope Array (CTA) is the next generation very high-energy gamma-ray observatory, with at least 10 times higher sensitivity than current instruments. CTA will comprise several tens of Imaging Atmospheric Cherenkov Telescopes (IACTs) operated in array-mode and divided into three size classes: large, medium and small telescopes. The total reflective surface could be up to 10,000 m2 requiring unprecedented technological efforts. The properties of the reflector directly influence the telescope performance and thus constitute a fundamental ingredient to improve and maintain the sensitivity. The R&D status of lightweight, reliable and cost-effective mirror facets for the CTA telescope reflectors for the different classes of telescopes is reviewed in this paper.

  6. Design and Operation of FACT -- The First G-APD Cherenkov Telescope

    CERN Document Server

    Anderhub, H; Biland, A; Boccone, V; Braun, I; Bretz, T; Buß, J; Cadoux, F; Commichau, V; Djambazov, L; Dorner, D; Einecke, S; Eisenacher, D; Gendotti, A; Grimm, O; von Gunten, H; Haller, C; Hildebrand, D; Horisberger, U; Huber, B; Kim, K -S; Knoetig, M L; K"ohne, J H; Kr"ahenb"uhl, T; Krumm, B; Lee, M; Lorenz, E; Lustermann, W; Lyard, E; Mannheim, K; Meharga, M; Meier, K; Montaruli, T; Neise, D; Nessi-Tedaldi, F; Overkemping, A -K; Paravac, A; Pauss, F; Renker, D; Rhode, W; Ribordy, M; R"oser, U; Stucki, J -P; Schneider, J; Steinbring, T; Temme, F; Thaele, J; Tobler, S; Viertel, G; Vogler, P; Walter, R; Warda, K; Weitzel, Q; Z"anglein, M

    2013-01-01

    The First G-APD Cherenkov Telescope (FACT) is designed to detect cosmic gamma-rays with energies from several hundred GeV up to about 10 TeV using the Imaging Atmospheric Cherenkov Technique. In contrast to former or existing telescopes, the camera of the FACT telescope is comprised of solid-state Geiger-mode Avalanche Photodiodes (G-APD) instead of photomultiplier tubes for photo detection. It is the first full-scale device of its kind employing this new technology. The telescope is operated at the Observatorio del Roque de los Muchachos (La Palma, Canary Islands, Spain) since fall 2011. This paper describes in detail the design, construction and operation of the system, including hardware and software aspects. Technical experiences gained after one year of operation are discussed and conclusions with regard to future projects are drawn.

  7. Photon Detection Efficiency Measurements of the VERITAS Cherenkov Telescope Photomultipliers after four Years of Operation

    CERN Document Server

    Gazda, Eliza; Otte, Nepomuk; Richards, Gregory

    2016-01-01

    The photon detection efficiency of two sets of R10560-100-20 superbialkali photomultiplier tubes from Hamamatsu were measured between 200 nm and 750 nm to quantify a possible degradation of the photocathode sensitivity after four years of operation in the cameras of the VERITAS Cherenkov telescopes. A sample of 20 photomultiplier tubes, which was removed from the telescopes was compared with a sample of 20 spare photomultiplier tubes, which had been kept in storage. It is found that the average photocathode sensitivity marginally increased below 300 nm and dropped by 10% to 30% above 500 nm. The average photocathode sensitivity folded with the Cherenkov spectrum emitted by particles in air showers, however, reveals a consistent detection yield of 18.9+/-0.2% and 19.1+/-0.2% for the sample removed from the telescope and the spare sample, respectively.

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

    CERN Document Server

    Giomi, Matteo; Maier, Gernot

    2016-01-01

    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...

  9. Photosensor Characterization for the Cherenkov Telescope Array: Silicon Photomultiplier versus Multi-Anode Photomultiplier Tube

    CERN Document Server

    Bouvier, Aurelien; Johnson, Caitlin; Kuznetsov, Andrey; Williams, David; Otte, Nepomuk; Strausbaugh, Robert; Hidaka, Naoya; Tajima, Hiroyasu; Hinton, Jim; White, Richard; Errando, Manel; Mukherjee, Reshmi

    2013-01-01

    Photomultiplier tube technology has been the photodetector of choice for the technique of imaging atmospheric Cherenkov telescopes since its birth more than 50 years ago. Recently, new types of photosensors are being contemplated for the next generation Cherenkov Telescope Array. It is envisioned that the array will be partly composed of telescopes using a Schwarzschild-Couder two mirror design never built before which has significantly improved optics. The camera of this novel optical design has a small plate scale which enables the use of compact photosensors. We present an extensive and detailed study of the two most promising devices being considered for this telescope design: the silicon photomultiplier and the multi-anode photomultiplier tube. We evaluated their most critical performance characteristics for imaging gamma-ray showers, and we present our results in a cohesive manner to clearly evaluate the advantages and disadvantages that both types of device have to offer in the context of GeV-TeV gamma...

  10. The Physics and Nuclear Nonproliferation Goals of WATCHMAN: A WAter CHerenkov Monitor for ANtineutrinos

    CERN Document Server

    Askins, M; Bernstein, A; Dazeley, S; Dye, S T; Handler, T; Hatzikoutelis, A; Hellfeld, D; Jaffke, P; Kamyshkov, Y; Land, B J; Learned, J G; Marleau, P; Mauger, C; Gann, G D Orebi; Roecker, C; Rountree, S D; Shokair, T M; Smy, M B; Svoboda, R; Sweany, M; Vagins, M R; van Bibber, K A; Vogelaar, R B; Wetstein, M J; Yeh, M

    2015-01-01

    This article describes the physics and nonproliferation goals of WATCHMAN, the WAter Cherenkov Monitor for ANtineutrinos. The baseline WATCHMAN design is a kiloton scale gadolinium-doped (Gd) light water Cherenkov detector, placed 13 kilometers from a civil nuclear reactor in the United States. In its first deployment phase, WATCHMAN will be used to remotely detect a change in the operational status of the reactor, providing a first- ever demonstration of the potential of large Gd-doped water detectors for remote reactor monitoring for future international nuclear nonproliferation applications. During its first phase, the detector will provide a critical large-scale test of the ability to tag neutrons and thus distinguish low energy electron neutrinos and antineutrinos. This would make WATCHMAN the only detector capable of providing both direction and flavor identification of supernova neutrinos. It would also be the third largest supernova detector, and the largest underground in the western hemisphere. In a...

  11. Detection of the Cherenkov light diffused by Sea Water with the ULTRA Experiment

    CERN Document Server

    Agnetta, G; Biondo, B; Brogueira, P; Cappa, A; Catalano, O; Chauvin, J; Staiti, G D'Ali'; Dattoli, M; Espirito-Santo, M C; Fava, L; Galeotti, P; Giarrusso, S; Gugliotta, G; La Rosa, G; Lebrun, D; Maccarone, M C; Mangano, A; Melo, L; Moreggia, S; Pimenta, M; Russo, F; Saavedra, O; Segreto, A; Silva, J C; Stassi, P; Tome', B; Vallania, P; Vigorito, C

    2007-01-01

    The study of Ultra High Energy Cosmic Rays represents one of the most challenging topic in the Cosmic Rays and in the Astroparticle Physics fields. The interaction of primary particles with atmospheric nuclei produces a huge Extensive Air Shower together with isotropic emission of UV fluorescence light and highly directional Cherenkov photons, that are reflected/diffused isotropically by the impact on the Earth's surface or on high optical depth clouds. For space-based observations, detecting the reflected Cherenkov signal in a delayed coincidence with the fluorescence light improves the accuracy of the shower reconstruction in space and in particular the measurement of the shower maximum, giving a strong signature for discriminating hadrons and neutrinos, and helping to estimate the primary chemical composition. Since the Earth's surface is mostly covered by water, the ULTRA (UV Light Transmission and Reflection in the Atmosphere)experiment has been designed to provide the diffusing properties of sea water, ...

  12. Monte Carlo Performance Studies of Candidate Sites for the Cherenkov Telescope Array

    CERN Document Server

    Maier, G; Bernlöhr, K; Bregeon, J; Di Pierro, F; Hassan, T; Jogler, T; Hinton, J; Moralejo, A; Wood, M

    2015-01-01

    The Cherenkov Telescope Array (CTA) is the next-generation gamma-ray observatory with sensitivity in the energy range from 20 GeV to beyond 300 TeV. CTA is proposed to consist of two arrays of 40-100 imaging atmospheric Cherenkov telescopes, with one site located in each of the Northern and Southern Hemispheres. The evaluation process for the candidate sites for CTA is supported by detailed Monte Carlo simulations, which take different attributes like site altitude and geomagnetic field configuration into account. In this contribution we present the comparison of the sensitivity and performance of the different CTA site candidates for the measurement of very-high energy gamma rays.

  13. On the Use of Cherenkov Telescopes for Outer Solar System Body Occultations

    CERN Document Server

    Lacki, Brian C

    2014-01-01

    Imaging Atmosphere Cherenkov Telescopes (IACT) 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 meters 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 percent. I consider how often IACTs can observe occultations by members of different TJO populations, including Centaurs, Kuiper Belt Objects (KB...

  14. Sensitivity of the space-based CHerenkov from Astrophysical Neutrinos Telescope (CHANT)

    CERN Document Server

    Neronov, A; Anchordoqui, L A; Adams, J; Olinto, A V

    2016-01-01

    Neutrinos with energies in the PeV to EeV range produce upgoing extensive air showers when they interact underground close enough to the surface of the Earth. We study the possibility for detection of such showers with a system of very wide field-of-view imaging atmospheric Cherenkov telescopes, named CHANT for CHerenkov from Astrophysical Neutrinos Telescope, pointing down to a strip below the Earth's horizon from space. We find that CHANT provides sufficient sensitivity for the study of the astrophysical neutrino flux in a wide energy range, from 10~PeV to 10~EeV. A space-based CHANT system can discover and study in detail the cosmogenic neutrino flux originating from interactions of ultra-high-energy cosmic rays in the intergalactic medium.

  15. Data analysis for solar neutrinos observed by water Cherenkov detectors{sup *}

    Energy Technology Data Exchange (ETDEWEB)

    Koshio, Yusuke [Okayama University, Okayama (Japan)

    2016-04-15

    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. (orig.)

  16. Analogue Sum ASIC for L1 Trigger Decision in Cherenkov Telescope Cameras

    CERN Document Server

    Barrio, Joan Abel; Boix, Joan; Delagnes, Eric; Delgado, Carlos; Coromina, Lluis Freixas; Gascon, David; Guilloux, Fabrice; Coto, Ruben Lopez; Martinez, Gustavo; Sanuy, Andreu; Tejedor, Luis Angel

    2014-01-01

    The Cherenkov Telescope Array (CTA) project aims to build the largest ground-based gamma-ray observatory based on an array of Imaging Atmospheric Cherenkov Telescopes (IACTs). The CTA will implement a multi-level trigger system to distinguish between gamma ray-like induced showers and background images induced by night sky background (NSB) light. The trigger system is based on coincident detections among pixels (level 0 trigger), clusters of pixels (level 1) or telescopes. In this article, the first version of the application specific integrated circuit (ASIC) for Level 1 trigger system is presented, capable of working with different Level 0 strategies and different trigger region sizes. In addition, it complies with all the requirements specified by the CTA project, specially the most critical ones as regards noise, bandwidth, dynamic range and power consumption. All these features make the presented system very suitable for use in the CTA cameras and improve the features of discrete components prototypes of...

  17. The photon detector of the HERMES dual-radiator RICH

    Science.gov (United States)

    Aschenauer, E. C.; Van der Kerckhove, K.

    1999-08-01

    To provide hadron identification over the full kinematic range (2-20GeV) of the HERMES experiment, the gas threshold Cherenkov counters were replaced by a dual-radiator ring-imaging Cherenkov detectors incorporating for the first time aerogel (SiO2) and C4F10 gas as radiator materials. This combination of radiators requires a photon detector that is sensitive over wavelengths from ultraviolet to 700nm. Commercially available `3/4 in.' photo-multipliers were chosen to form an array of 2000 for each of two photon-detectors. Exhaustive calibration and sorting of the phototubes prior to installation resulted in very low noise hit rates in the LeCroy PCOS4 readout system, with a uniform effective threshold of 0.1 photo-electrons.

  18. Radiation of relativistic electrons in a periodic wire structure

    Energy Technology Data Exchange (ETDEWEB)

    Soboleva, V.V., E-mail: sobolevaveronica@mail.ru; Naumenko, G.A.; Bleko, V.V.

    2015-07-15

    We present in this work the experimental investigation of the interaction of relativistic electron field with periodic wire structures. We used two types of the targets in experiments: flat wire target and sandwich wire target that represent the right triangular prism. The measurements were done in millimeter wavelength region (10–40 mm) on the relativistic electron beam with energy of 6.2 MeV in far-field zone. We showed that bunched electron beam passing near wire metamaterial prism generates coherent Cherenkov radiation. The experiments with flat wire target were carried out in two geometries. In the first geometry the electron beam passed close to the flat wire target surface. In the second case the electron beam passed through the flat wire structure with generation of a coherent backward transition radiation (CBTR). The comparison of the Cherenkov radiation intensity and BTR intensity from the flat wire target and from the flat conductive target (conventional BTR) was made.

  19. Observing muon decays in water Cherenkov detectors at the Pierre Auger Observatory

    OpenAIRE

    Allison, P.; Arneodo, F.; Bertou, X.; Busca, N.G.; Ghia, P.L.; C. Medina; Navarra, G.; Nellen, L.; Ibarguen, H. Salazar; Ranchon, S.; Urban, M.; Villasenor, L.; Collaboration, for the Pierre Auger

    2005-01-01

    Muons decaying in the water volume of a Cherenkov detector of the Pierre Auger Observatory provide a useful calibration point at low energy. Using the digitized waveform continuously recorded by the electronics of each tank, we have devised a simple method to extract the charge spectrum of the Michel electrons, whose typical signal is about 1/8 of a crossing vertical muon. This procedure, moreover, allows continuous monitoring of the detector operation and of its water level. We have checked ...

  20. Atmospheric multiple scattering of fluorescence and Cherenkov light emitted by extensive air showers

    OpenAIRE

    Pekala, J.; Homola, P.; Wilczynska, B.; Wilczynski, H.

    2009-01-01

    Atmospheric scattering of light emitted by an air shower not only attenuates direct fluorescence light from the shower, but also contributes to the observed shower light. So far only direct and singly-scattered Cherenkov photons have been taken into account in routine analyses of the observed optical image of air showers. In this paper a Monte Carlo method of evaluating the contribution of multiply scattered light to the optical air shower image is presented, as well as results of simulations...

  1. Prospects for CHIPS (R&D of Water Cherenkov Detectors in Mine Pits)

    OpenAIRE

    Lang, Karol

    2015-01-01

    CHIPS is an R&D program focused on designing and constructing a cost-effective large water Cherenkov detector (WCD) to study neutrino oscillations using accelerator beams. Traditional WCD's with a low energy threshold have been built in special large underground caverns. Civil construction of such facilities is costly and the excavation phase significantly delays the detector installation although, in the end, it offers a well-shielded apparatus with versatile physics program. Using concepts ...

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

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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. Efficiency calibration of a liquid scintillation counter for 90Y Cherenkov counting

    International Nuclear Information System (INIS)

    In this paper a complete and self-consistent method for 90Sr determination in environmental samples is presented. It is based on the Cherenkov counting of 90Y with a conventional liquid scintillation counter. The effects of color quenching on the counting efficiency and background are carefully studied. A working curve is presented which allows to quantify the correction in the counting efficiency depending on the color quenching strength. (orig.)

  5. Performance of the Two Aerogel Cherenkov Detectors of the JLab Hall A Hadron Spectrometer

    OpenAIRE

    Marrone, S.; Wojtsekhowski, B. B.; Acha, A.; Cisbani, E.; M. COMAN; Cusanno, F.; de Jager, C. W.; De Leo, R; Gao, H.; Garibaldi, F.; Higinbotham, D.W.; Iodice, M.; LeRose, J.J.; Macchia, D; Markowitz, P.

    2008-01-01

    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 ...

  6. Simulation of Imaging Atmospheric Cherenkov Telescopes with CORSIKA and sim_telarray

    OpenAIRE

    Bernlohr, Konrad

    2008-01-01

    Imaging Atmospheric Cherenkov Telescopes (IACTs) have resulted in a breakthrough in very-high energy (VHE) gamma-ray astrophysics. While early IACT installations faced the problem of detecting any sources at all, current instruments are able to see many sources, often over more than two orders of magnitude in energy. As instruments and analysis methods have matured, the requirements for calibration and modelling of physical and instrumental effects have increased. In this article, a set of Mo...

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

    Science.gov (United States)

    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.

  8. Solar panels as air Cherenkov detectors for extremely high energy cosmic rays

    OpenAIRE

    Cecchini, S.; D'Antone, I; Esposti, L. Degli; Giacomelli, G.; Guerra, M; Lax, I; Mandrioli, G.; Parretta, A.; Sarno, A.; Schioppo, R.; Sorel, M.; Spurio, M.

    2000-01-01

    Increasing interest towards the observation of the highest energy cosmic rays has motivated the development of new detection techniques. The properties of the Cherenkov photon pulse emitted in the atmosphere by these very rare particles indicate low-cost semiconductor detectors as good candidates for their optical read-out. The aim of this paper is to evaluate the viability of solar panels for this purpose. The experimental framework resulting from measurements performed with suitably-designe...

  9. The optical reflector system for the CANGAROO-II imaging atmospheric Cherenkov telescope

    CERN Document Server

    Kawachi, A; Jimbo, J; Kamei, S; Kifune, T; Kubo, H; Kushida, J; Le Bohec, S; Miyawaki, K; Mori, M; Nishijima, K; Patterson, J R; Suzuki, R; Tanimori, T; Yanagita, S; Yoshikoshi, T; Yuki, A

    2001-01-01

    A new imaging atmospheric Cherenkov telescope (CANGAROO-II) with a light-weight reflector has been constructed. Light, robust, and durable mirror facets of containing CFRP (Carbon Fiber Reinforced Plastic) laminates were developed for the telescope. The attitude of each facet can be adjusted by stepping motors. In this paper, we describe the design, manufacturing, alignment procedure, and the performance of the CANGAROO-II optical reflector system.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-11-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. Inauguration and First Light of the GCT-M Prototype for the Cherenkov Telescope Array

    CERN Document Server

    Watson, J J; Abchiche, A; Allan, D; Amans, J -P; Armstrong, T P; Balzer, A; Berge, D; Boisson, C; Bousquet, J -J; Brown, A M; Bryan, M; Buchholtz, G; Chadwick, P M; Costantini, H; Cotter, G; Daniel, M K; De Frondat, F; Dournaux, J -L; Dumas, D; Ernenwein, J -P; Fasola, G; Funk, S; Gironnet, J; Graham, J A; Greenshaw, T; Hervet, O; Hidaka, N; Hinton, J A; Huet, J -M; Jegouzo, I; Jogler, T; Kraus, M; Lapington, J S; Laporte, P; Lefaucheur, J; Markoff, S; Melse, T; Mohrmann, L; Molyneux, P; Nolan, S J; Okumura, A; Osborne, J P; Parsons, R D; Rosen, S; Ross, D; Rowell, G; Rulten, C B; Sato, Y; Sayéde, F; Schmoll, J; Schoorlemmer, H; Servillat, M; Sol, H; Stamatescu, V; Stephan, M; Stuik, R; Sykes, J; Tajima, H; Thornhill, J; Tibaldo, L; Trichard, C; Vink, J; White, R; Yamane, N; Zech, A; Zink, A; Zorn, J

    2016-01-01

    The Gamma-ray Cherenkov Telescope (GCT) is a candidate for the Small Size Telescopes (SSTs) of the Cherenkov Telescope Array (CTA). Its purpose is to extend the sensitivity of CTA to gamma-ray energies reaching 300 TeV. Its dual-mirror optical design and curved focal plane enables the use of a compact camera of 0.4 m diameter, while achieving a field of view of above 8 degrees. Through the use of the digitising TARGET ASICs, the Cherenkov flash is sampled once per nanosecond continuously and then digitised when triggering conditions are met within the analogue outputs of the photosensors. Entire waveforms (typically covering 96 ns) for all 2048 pixels are then stored for analysis, allowing for a broad spectrum of investigations to be performed on the data. Two prototypes of the GCT camera are under development, with differing photosensors: Multi-Anode Photomultipliers (MAPMs) and Silicon Photomultipliers (SiPMs). During November 2015, the GCT MAPM (GCT-M) prototype camera was integrated onto the GCT structure...

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

    CERN Document Server

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

    2015-01-01

    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 wi...

  14. TARGET: A Digitizing And Trigger ASIC For The Cherenkov Telescope Array

    CERN Document Server

    Funk, S; Katagiri, H; Kraus, M; Okumura, A; Schoorlemmer, H; Shigenaka, A; Tajima, H; Tibaldo, L; Varner, G; Zink, A; Zorn, J

    2016-01-01

    The future ground-based gamma-ray observatory Cherenkov Telescope Array (CTA) will feature multiple types of imaging atmospheric Cherenkov telescopes, each with thousands of pixels. To be affordable, camera concepts for these telescopes have to feature low cost per channel and at the same time meet the requirements for CTA in order to achieve the desired scientific goals. We present the concept of the TeV Array Readout Electronics with GSa/s sampling and Event Trigger (TARGET) Application Specific Circuit (ASIC), envisaged to be used in the cameras of various CTA telescopes, e.g. the Gamma-ray Cherenkov Telescope (GCT), a proposed 2-Mirror Small-Sized Telescope, and the Schwarzschild-Couder Telescope (SCT), a proposed Medium-Sized Telescope. In the latest version of this readout concept the sampling and trigger parts are split into dedicated ASICs, TARGET C and T5TEA, both providing 16 parallel input channels. TARGET C features a tunable sampling rate (usually 1 GSa/s), a 16k sample deep buffer for each chann...

  15. Radiation spectrum of charged particles moving in magnetic field in a transparent medium

    International Nuclear Information System (INIS)

    In this paper, we report our investigations on the spectral distribution of radiation power for the charged particles moving along an arbitrary trajectory in a transparent medium by means of Lorentz self-interaction method. Numerical calculations of the fine structure of the radiation spectrum of two electrons moving one by one in a spiral in medium were carried out in the case of relativistic transverse velocity component. We also investigated the power radiation of two electrons in a medium in terms of their placement along a spiral. From high-accuracy calculations, we obtained the spectral distribution of the synchrotron-Cherenkov radiation power of an electron moving in a spiral. The synchrotron-Cherenkov radiation is a unified process with interesting properties. (authors)

  16. Diseño de montura Davies-Cotton de telescopio Cherenkov de 6m de diámetro para el proyecto CTA

    Science.gov (United States)

    Actis, M.; Ringegni, P.; Antico, F.; Bottani, A.; Vallejo, G.; Ochoa, I.; Marconi, D.; Supanitsky, A. D.; Rovero, A. C.

    For the next generation of ground-based instruments for the observation of gamma-rays, the construction of 6 m diameter Cherenkov telescopes is foreseen. We have proposed a design of Davies-Cotton mount for such a telescope, within Cherenkov Telescope Array specifications, and evaluated its mechanical and optical performance. FULL TEXT IN SPANISH

  17. Calibration and performance of the photon sensor response of FACT -- The First G-APD Cherenkov telescope

    CERN Document Server

    Biland, A; Buß, J; Commichau, V; Djambazov, L; Dorner, D; Einecke, S; Eisenacher, D; Freiwald, J; Grimm, O; von Gunten, H; Haller, C; Hempfling, C; Hildebrand, D; Hughes, G; Horisberger, U; Knoetig, M L; Krähenbühl, T; Lustermann, W; Lyard, E; Mannheim, K; Meier, K; Mueller, S; Neise, D; Overkemping, A -K; Paravac, A; Pauss, F; Rhode, W; Röser, U; Stucki, J -P; Steinbring, T; Temme, F; Thaele, J; Vogler, P; Walter, R; Weitzel, Q

    2014-01-01

    The First G-APD Cherenkov Telescope (FACT) is the first in-operation test of the performance of silicon photo detectors in Cherenkov Astronomy. For more than two years it is operated on La Palma, Canary Islands (Spain), for the purpose of long-term monitoring of astrophysical sources. For this, the performance of the photo detectors is crucial and therefore has been studied in great detail. Special care has been taken for their temperature and voltage dependence implementing a correction method to keep their properties stable. Several measurements have been carried out to monitor the performance. The measurements and their results are shown, demonstrating the stability of the gain below the percent level. The resulting stability of the whole system is discussed, nicely demonstrating that silicon photo detectors are perfectly suited for the usage in Cherenkov telescopes, especially for long-term monitoring purpose.

  18. Experimental study of the atmospheric neutrino backgrounds for proton decay to positron and neutral pion searches in water Cherenkov detectors

    CERN Document Server

    Mine, S; Andringa, S; Aoki, S; Argyriades, J; Asakura, K; Ashie, R; Berghaus, F; Berns, H; Bhang, H; Blondel, A; Borghi, S; Bouchez, J; Burguet-Castell, J; Casper, D; Catala, J; Cavata, C; Cervera-Villanueva, Anselmo; Chen, S M; Cho, K O; Choi, J H; Dore, U; Espinal, X; Fechner, M; Fernández, E; Fujii, Y; Fukuda, Y; Gomez-Cadenas, J; Gran, R; Hara, T; Hasegawa, M; Hasegawa, T; Hayato, Y; Helmer, R L; Hiraide, K; Hosaka, J; Ichikawa, A K; Iinuma, M; Ikeda, A; Ishida, T; Ishihara, K; Ishii, T; Ishitsuka, M; Itow, Y; Iwashita, T; Jang, H I; Jeon, E J; Jeong, I S; Joo, K K; Jover, G; Jung, C K; Kajita, T; Kameda, J; Kaneyuki, K; Kato, I; Kearns, E; Kim, C O; Khabibullin, M; Khotjantsev, A; Kielczewska, D; Kim, J Y; Kim, S B; Kitching, P; Kobayashi, K; Kobayashi, T; Konaka, A; Koshio, Y; Kropp, W; Kudenko, Yu; Kuno, Y; Kurimoto, Y; Kutter, T; Learned, J; Likhoded, S; Lim, I T; Loverre, P F; Ludovici, L; Maesaka, H; Mallet, J; Mariani, C; Matsuno, S; Matveev, V; McConnel, K; McGrew, C; Mikheyev, S; Minamino, A; Mineev, O; Mitsuda, C; Miura, M; Moriguchi, Y; Moriyama, S; Nakadaira, T; Nakahata, M; Nakamura, K; Nakano, I; Nakaya, T; Nakayama, S; Namba, T; Nambu, R; Nawang, S; Nishikawa, K; Nitta, K; Nova, F; Novella, P; Obayashi, Y; Okada, A; Okumura, K; Oser, S M; Oyama, Y; Pac, M Y; Pierre, F; Rodríguez, A; Saji, C; Sakuda, M; Sánchez, F; Scholberg, K; Schroeter, R; Sekiguchi, M; Shiozawa, M; Shiraishi, K; Sitjes, G; Smy, M; Sobel, H; Sorel, M; Stone, J; Sulak, L; Suzuki, A; Suzuki, Y; Tada, M; Takahashi, T; Takenaga, Y; Takeuchi, Y; Taki, K; Takubo, Y; Tamura, N; Tanaka, M; Terri, R; T'Jampens, S; Tornero-Lopez, A; Totsuka, Y; Vagins, M; Whitehead, L; Walter, C W; Wang, W; Wilkes, R J; Yamada, S; Yamada, Y; Yamamoto, S; Yanagisawa, C; Yershov, N; Yokoyama, H; Yokoyama, M; Yoo, J; Yoshida, M; Zalipska, J

    2008-01-01

    The atmospheric neutrino background for proton decay to positron and neutral pion in ring imaging water Cherenkov detectors is studied with an artificial accelerator neutrino beam for the first time. In total, about 314,000 neutrino events corresponding to about 10 megaton-years of atmospheric neutrino interactions were collected by a 1,000 ton water Cherenkov detector (KT). The KT charged-current single neutral pion production data are well reproduced by simulation programs of neutrino and secondary hadronic interactions used in the Super-Kamiokande (SK) proton decay search. The obtained proton to positron and neutral pion background rate by the KT data for SK from the atmospheric neutrinos whose energies are below 3 GeV is about two per megaton-year. This result is also relevant to possible future, megaton-scale water Cherenkov detectors.

  19. Development of the optical system for the SST-1M telescope of the Cherenkov Telescope Array observatory

    CERN Document Server

    Seweryn, K; Błocki, J.; Bogacz, L.; Bulik, T.; Cadoux, F.; Christov, A.; Chruślińska, M.; Curyło, M.; della Volpe, D.; Dyrda, M.; Favre, Y.; Frankowski, A.; Grudnik, Ł.; Grudzińska, M.; Heller, M.; Idźkowski, B.; Jamrozy, M.; Janiak, M.; Kasperek, J.; Lalik, K.; Lyard, E.; Mach, E.; Mandat, D.; Marszałek, A.; Michałowski, J.; Moderski, R.; Montaruli, T.; Neronov, A.; Niemiec, J.; Ostrowski, M.; Paśko, P.; Pech, M.; Porcelli, A.; Prandini, E.; Pueschel, E.; Rajda, P.; Rameez, M.; Rozwadowski, P.; Schioppa, E. jr; Schovanek, P.; Skowron, K.; Sliusar, V.; Sowiński, M.; Stawarz, Ł.; Stodulska, M.; Stodulski, M.; Toscano, S.; Pujadas, I. Troyano; Walter, R.; Wiȩcek, M.; Zagdański, A.; Ziȩtara, K.; Żychowski, P.; Barciński, T.; Karczewski, M.; Kukliński, J. Nicolau; Płatos, Ł.; Rataj, M.; Wawer, P.; Wawrzaszek, R.

    2015-01-01

    The prototype of a Davies-Cotton small size telescope (SST-1M) has been designed and developed by a consortium of Polish and Swiss institutions and proposed for the Cherenkov Telescope Array (CTA) observatory. The main purpose of the optical system is to focus the Cherenkov light emitted by extensive air showers in the atmosphere onto the focal plane detectors. The main component of the system is a dish consisting of 18 hexagonal mirrors with a total effective collection area of 6.47 m2 (including the shadowing and estimated mirror reflectivity). Such a solution was chosen taking into account the analysis of the Cherenkov light propagation and based on optical simulations. The proper curvature and stability of the dish is ensured by the mirror alignment system and the isostatic interface to the telescope structure. Here we present the design of the optical subsystem together with the performance measurements of its components.

  20. Fabrication of silica aerogel with $n$ = 1.08 for $e^+/\\mu ^+$ separation in a threshold Cherenkov counter of the J-PARC TREK/E36 experiment

    CERN Document Server

    Tabata, Makoto; Kawai, Hideyuki; Igarashi, Youichi; Imazato, Jun; Shimizu, Suguru; Yamazaki, Hirohito

    2015-01-01

    This study presents the development of hydrophobic silica aerogel for use as a radiator in threshold-type Cherenkov counters. These counters are to be used for separating positrons and positive muons produced by kaon decay in the J-PARC TREK/E36 experiment. We chose to employ aerogel with a refractive index of 1.08 to identify charged particles with momenta of approximately 240 MeV/$c$, and the radiator block shape was designed with a trapezoidal cross-section to fit the barrel region surrounding the kaon stopping target in the center of the TREK/E36 detector system. Including spares, we obtained 30 crack-free aerogel blocks segmented into two layers, each layer having a thickness of 2 cm and a length of 18 cm, to fill 12 counter modules. Optical measurements showed that the produced aerogel tiles had the required refractive indices and transparency.

  1. Observing muon decays in water Cherenkov detectors at the Pierre Auger Observatory

    CERN Document Server

    Allison, P; Bertou, X; Busca, N G; Ghia, P L; Medina, C; Navarra, G; Nellen, L; Ibarguen, H S; Ranchon, S; Urban, M; Villaseñor, L

    2005-01-01

    Muons decaying in the water volume of a Cherenkov detector of the Pierre Auger Observatory provide a useful calibration point at low energy. Using the digitized waveform continuously recorded by the electronics of each tank, we have devised a simple method to extract the charge spectrum of the Michel electrons, whose typical signal is about 1/8 of a crossing vertical muon. This procedure, moreover, allows continuous monitoring of the detector operation and of its water level. We have checked the procedure with high statistics on a test tank at the Observatory base and applied with success on the whole array.

  2. Atmospheric multiple scattering of fluorescence and Cherenkov light emitted by extensive air showers

    CERN Document Server

    Pekala, J; Wilczynska, B; Wilczynski, H; 10.1016/j.nima.2009.03.244

    2009-01-01

    Atmospheric scattering of light emitted by an air shower not only attenuates direct fluorescence light from the shower, but also contributes to the observed shower light. So far only direct and singly-scattered Cherenkov photons have been taken into account in routine analyses of the observed optical image of air showers. In this paper a Monte Carlo method of evaluating the contribution of multiply scattered light to the optical air shower image is presented, as well as results of simulations and a parameterization of scattered light contribution to measured shower signal.

  3. The ASTRI Project: a mini-array of dual-mirror small Cherenkov telescopes for CTA

    OpenAIRE

    La Palombara, N.; Agnetta, G; Antonelli, L.A.; Bastieri, D.; Bellassai, G.; Belluso, M; Bigongiari, C.; Billotta, S.; Biondo, B.; Bonanno, G.; Bonnoli, G.; Bruno, P; Bulgarelli, A.; Canestrari, R.; Capalbi, M.

    2013-01-01

    ASTRI is a flagship project of the Italian Ministry of Education, University and Research, which aims to develop an end-to-end prototype of the CTA small-size telescope. The proposed design is characterized by a dual-mirror Schwarzschild-Couder configuration and a camera based on Silicon photo-multipliers, two challenging but innovative technological solutions which will be adopted for the first time on a Cherenkov telescope. Here we describe the current status of the project, the expected pe...

  4. A new solution for mirror coating in $\\gamma$-ray Cherenkov Astronomy

    OpenAIRE

    Bonardi, Antonio; Pühlhofer, Gerd; Hermanutz, Stephan; Santangelo, Andrea

    2014-01-01

    In the $\\gamma$-ray Cherenkov Astronomy framework mirror coating plays a crucial role in defining the light response of the telescope. We carried out a study for new mirror coating solutions with both a numerical simulation software and a vacuum chamber for small sample production. In this article, we present a new mirror coating solution consisting of a 28-layer interferometric SiO$_{2}$-TiO$_{2}$-HfO$_{2}$ design deposited on a glass substrate, whose average reflectance is above $90\\%$ for ...

  5. Large Size Telescope camera support structures for the Cherenkov Telescope Array

    CERN Document Server

    Deleglise, G; Lamanna, G

    2013-01-01

    The design of the camera support structures for the Cherenkov Telescope Array (CTA) Large Size Telescopes (LSTs) is based on an elliptical arch geometry reinforced along its orthogonal projection by two symmetric sets of stabilizing ropes. The main requirements in terms of minimal camera displacement, minimal weight, minimal shadowing on the telescope mirror, maximal strength of the structures and fast dynamical stabilization have led to the application of Carbon Fibre Plastic Reinforced (CFPR) technologies. This work presents the design, static and dynamic performance of the telescope fulfilling critical specifications for the major scientific objectives of the CTA LST, e.g. Gamma Ray Burst detection.

  6. The ASTRI Project: a mini-array of dual-mirror small Cherenkov telescopes for CTA

    CERN Document Server

    La Palombara, N; Antonelli, L A; Bastieri, D; Bellassai, G; Belluso, M; Bigongiari, C; Billotta, S; Biondo, B; Bonanno, G; Bonnoli, G; Bruno, P; Bulgarelli, A; Canestrari, R; Capalbi, M; Caraveo, P; Carosi, A; Cascone, E; Catalano, O; Cereda, M; Conconi, P; Conforti, V; Cusumano, G; De Caprio, V; De Luca, A; Di Paola, A; Di Pierro, F; Fantinel, D; Fiorini, M; Fugazza, D; Gardiol, D; Ghigo, M; Gianotti, F; Giarrusso, S; Giro, E; Grillo, A; Impiombato, D; Incorvaia, S; La Barbera, A; La Parola, V; La Rosa, G; Lessio, L; Leto, G; Lombardi, S; Lucarelli, F; Maccarone, M C; Malaguti, G; Malaspina, G; Mangano, V; Marano, D; Martinetti, E; Millul, R; Mineo, T; Mistó, A; Morello, C; Morlino, G; Panzera, M R; Pareschi, G; Rodeghiero, G; Romano, P; Russo, F; Sacco, B; Sartore, N; Schwarz, J; Segreto, A; Sironi, G; Sottile, G; Stamerra, A; Strazzeri, E; Stringhetti, L; Tagliaferri, G; Testa, V; Timpanaro, M C; Toso, G; Tosti, G; Trifoglio, M; Vallania, P; Vercellone, S; Zitelli, V

    2013-01-01

    ASTRI is a flagship project of the Italian Ministry of Education, University and Research, which aims to develop an end-to-end prototype of the CTA small-size telescope. The proposed design is characterized by a dual-mirror Schwarzschild-Couder configuration and a camera based on Silicon photo-multipliers, two challenging but innovative technological solutions which will be adopted for the first time on a Cherenkov telescope. Here we describe the current status of the project, the expected performance and the possibility to realize a mini-array composed by a few small-size telescopes, which shall be placed at the final CTA Southern Site.

  7. Trends in the development of large area photon detectors for Cherenkov light imaging applications

    CERN Document Server

    Nappi, E

    2003-01-01

    Since the successful operations of hi-tech devices at OMEGA, DELPHI and SLD, the technique of Cherenkov light imaging has gone through an impressive and fruitful evolution driven by the conception of novel large area photon detectors. The well-assessed potentialities of thin CsI films, employed as reflective photoconverters in gas counters operated at atmospheric pressure, will be compared with the promising features of hybrid and multianode vacuum photomultipliers. Recently proposed single-photon gaseous detectors based on GEMs will also be reviewed.

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

    Science.gov (United States)

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

    2016-04-01

    Volcanic activity is regulated by the interaction of gas-liquid flow with conduit geometry. Hence, the quantitative understanding of the inner shallow structure of a volcano is mandatory to forecast the occurrence of dangerous stages of activity and mitigate volcanic hazards. Among the techniques used to investigate the underground structure of a volcano, muon imaging offers some advantages, as it provides a fine spatial resolution, and does not require neither spatially dense measurements in active zones, nor the implementation of cost demanding energizing systems, as when electric or active seismic sources are utilized. The principle of muon radiography is essentially the same as X-ray radiography: muons are more attenuated by higher density parts inside the target and thus information about its inner structure are obtained from the differential muon absorption. Up-to-date, muon imaging of volcanic structures has been mainly accomplished with detectors that employ planes of scintillator strips. These telescopes are exposed to different types of background noise (accidental coincidence of vertical shower particles, horizontal high-energy electrons, flux of upward going particles), whose amplitude is high relative to the tiny flux of interest. An alternative technique is based on the detection of the Cherenkov light produced by muons. The latter can be imaged as an annular pattern that contains the information needed to reconstruct both direction and energy of the particle. Cherenkov telescopes have never been utilized to perform muon imaging of volcanoes. Nonetheless, thanks to intrinsic features, they offer the possibility to detect the through-target muon flux with negligible levels of background noise. Under some circumstances, they would also provide a better spatial resolution and acceptance than scintillator-based telescopes. Furthermore, contrarily to the latter systems, Cherenkov detectors allow in-situ measurements of the open-sky energy spectrum of

  9. Performance of the SST-1M telescope for the Cherenkov Telescope Array observatory

    CERN Document Server

    Moderski, R; Błocki, J.; Bogacz, L.; Bulik, T.; Cadoux, F.; Christov, A.; Chruślińska, M.; Curyło, M.; della Volpe, D.; Dyrda, M.; Favre, Y.; Frankowski, A.; Grudnik, Ł.; Grudzińska, M.; Heller, M.; Idźkowski, B.; Jamrozy, M.; Janiak, M.; Kasperek, J.; Lalik, K.; Lyard, E.; Mach, E.; Mandat, D.; Marszałek, A.; Michałowski, J.; Montaruli, T.; Neronov, A.; Niemiec, J.; Ostrowski, M.; Paśko, P.; Pech, M.; Porcelli, A.; Prandini, E.; Pueschel, E.; Rajda, P.; Rameez, M.; Rozwadowski, P.; Schioppa, E. jr; Schovanek, P.; Seweryn, K.; Skowron, K.; Sliusar, V.; Sowiński, M.; Stawarz, Ł.; Stodulska, M.; Stodulski, M.; Toscano, S.; Pujadas, I. Troyano; Walter, R.; Wiȩcek, M.; Zagdański, A.; Ziȩtara, K.; Żychowski, P.

    2015-01-01

    The single mirror small-size telescope (SST-1M) is one of the telescope projects being proposed for the Cherenkov Telescope Array observatory by a sub-consortium of Polish and Swiss institutions. The SST-1M prototype structure is currently being constructed at the Institute of Nuclear Physics in Cracow, Poland, while the camera will be assembled at the University of Geneva, Switzerland. This prototype enables measurements of parameters having a decisive influence on the telescope performance. We present results of numerical simulations of the SST-1M performance based on such measurements. The telescope effective area, the expected trigger rates and the optical point spread function are calculated.

  10. Prototype of the SST-1M Telescope Structure for the Cherenkov Telescope Array

    CERN Document Server

    Niemiec, J; Błocki, J; Bogacz, L; Borkowski, J; Bulik, T; Cadoux, F; Christov, A; Curyło, M; della Volpe, D; Dyrda, M; Favre, Y; Frankowski, A; Grudnik, Ł; Grudzińska, M; Heller, M; Idźkowski, B; Jamrozy, M; Janiak, M; Kasperek, J; Lalik, K; Lyard, E; Mach, E; Mandat, D; Marszałek, A; Michałowski, J; Moderski, R; Montaruli, T; Neronov, A; Ostrowski, M; Paśko, P; Pech, M; Porcelli, A; Prandini, E; Rajda, P; Rameez, M; Schioppa, E jr; Schovanek, P; Seweryn, K; Skowron, K; Sliusar, V; Sowiński, M; Stawarz, Ł; Stodulska, M; Stodulski, M; Pujadas, I Troyano; Toscano, S; Walter, R; Wiȩcek, M; Zagdański, A; Ziȩtara, K

    2015-01-01

    A single-mirror small-size (SST-1M) Davies-Cotton telescope with a dish diameter of 4 m has been built by a consortium of Polish and Swiss institutions as a prototype for one of the proposed small-size telescopes for the southern observatory of the Cherenkov Telescope Array (CTA). The design represents a very simple, reliable, and cheap solution. The mechanical structure prototype with its drive system is now being tested at the Institute of Nuclear Physics PAS in Krakow. Here we present the design of the prototype and results of the performance tests of the structure and the drive and control system.

  11. Solar panels as air Cherenkov detectors for extremely high energy cosmic rays

    International Nuclear Information System (INIS)

    Increasing interest towards the observation of the highest energy cosmic rays has motivated the development of new detection techniques. The properties of the Cherenkov photon pulse emitted in the atmosphere by these very rare particles indicate low-cost semiconductor detectors as good candidates for their optical read-out. The aim of this paper is to evaluate the viability of solar panels for this purpose. The experimental framework resulting from measurements performed with suitably-designed solar cells and large conventional photovoltaic areas is presented. A discussion on the obtained and achievable sensitivities follows

  12. A new solution for mirror coating in $\\gamma$-ray Cherenkov Astronomy

    CERN Document Server

    Bonardi, Antonio; Hermanutz, Stephan; Santangelo, Andrea

    2014-01-01

    In the $\\gamma$-ray Cherenkov Astronomy framework mirror coating plays a crucial role in defining the light response of the telescope. We carried out a study for new mirror coating solutions with both a numerical simulation software and a vacuum chamber for small sample production. In this article, we present a new mirror coating solution consisting of a 28-layer interferometric SiO$_{2}$-TiO$_{2}$-HfO$_{2}$ design deposited on a glass substrate, whose average reflectance is above $90\\%$ for normally incident light in the wavelength range between 300 and 550 nm.

  13. FlashCam: a fully-digital camera for the medium-sized telescopes of the Cherenkov Telescope Array

    OpenAIRE

    Pühlhofer, G.; Bauer, C.; Bernhard, S.; Capasso, M.; Diebold, S; Eisenkolb, F.; Florin, D.; Föhr, C.; S Funk; Gadola, A.; Garrecht, F.; Hermann, G.; Jung, I.; Kalekin, O.(Erlangen Centre for Astroparticle Physics, Friedrich-Alexander-Universität Erlangen-Nürnberg, Erlangen, Germany); Kalkuhl, C.

    2015-01-01

    The FlashCam group is currently preparing photomultiplier-tube based cameras proposed for the medium-sized telescopes (MST) of the Cherenkov Telescope Array (CTA). The cameras are designed around the FlashCam readout concept which is the first fully-digital readout system for Cherenkov cameras, based on commercial FADCs and FPGAs as key components for the front-end electronics modules and a high performance camera server as back-end. This contribution describes the progress of the full-scale ...

  14. Gamma/hadron segregation for a ground based imaging atmospheric Cherenkov telescope using machine learning methods: Random Forest leads

    International Nuclear Information System (INIS)

    A detailed case study of γ-hadron segregation for a ground based atmospheric Cherenkov telescope is presented. We have evaluated and compared various supervised machine learning methods such as the Random Forest method, Artificial Neural Network, Linear Discriminant method, Naive Bayes Classifiers, Support Vector Machines as well as the conventional dynamic supercut method by simulating triggering events with the Monte Carlo method and applied the results to a Cherenkov telescope. It is demonstrated that the Random Forest method is the most sensitive machine learning method for γ-hadron segregation. (research papers)

  15. Particle Identification with Cherenkov detectors in the 2011 CALICE Tungsten Analog Hadronic Calorimeter Test Beam at the CERN SPS

    CERN Document Server

    Dannheim, D; Klempt, W; Lucaci Timoce, A; van der Kraaij, E

    2013-01-01

    In 2011 the CALICE Tungsten Analog Hadronic Calorimeter prototype (W-AHCAL) was exposed to mixed beams of electrons, pions, kaons and protons with momenta from 10 to 300 GeV in the CERN SPS H8 beam line. The selection of pion, kaon and proton samples is based on the information obtained from two Cherenkov threshold counters. This note presents the strategy for the particle identification, as well as the calibration, operation and analysis of the Cherenkov counters. Efficiency and sample-purity estimates are given for the data selected for the W-AHCAL data analysis.

  16. Muon data from a water Cherenkov detector prototype at Colorado State University

    Science.gov (United States)

    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.

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

    Science.gov (United States)

    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.

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

    CERN Document Server

    López-Coto, Rubén; Paoletti, Riccardo; Bigas, Oscar Blanch; Cortina, Juan

    2016-01-01

    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 alg...

  19. SST-GATE: A dual mirror telescope for the Cherenkov Telescope Array

    CERN Document Server

    Zech, A; Blake, S; Boisson, C; Costille, C; De-Frondat, F; Dournaux, J -L; Dumas, D; Fasola, G; Greenshaw, T; Hervet, O; Huet, J -M; Laporte, P; Rulten, C; Savoie, D; Sayede, F; Schmoll, J

    2013-01-01

    The Cherenkov Telescope Array (CTA) will be the world's first open observatory for very high energy gamma-rays. Around a hundred telescopes of different sizes will be used to detect the Cherenkov light that results from gamma-ray induced air showers in the atmosphere. Amongst them, a large number of Small Size Telescopes (SST), with a diameter of about 4 m, will assure an unprecedented coverage of the high energy end of the electromagnetic spectrum (above ~1TeV to beyond 100 TeV) and will open up a new window on the non-thermal sky. Several concepts for the SST design are currently being investigated with the aim of combining a large field of view (~9 degrees) with a good resolution of the shower images, as well as minimizing costs. These include a Davies-Cotton configuration with a Geiger-mode avalanche photodiode (GAPD) based camera, as pioneered by FACT, and a novel and as yet untested design based on the Schwarzschild-Couder configuration, which uses a secondary mirror to reduce the plate-scale and to all...

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

    CERN Document Server

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

    2015-01-01

    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 sy...

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

    International Nuclear Information System (INIS)

    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

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

    Science.gov (United States)

    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.

  3. Silicon Photomultiplier Research and Development Studies for the Large Size Telescope of the Cherenkov Telescope Array

    CERN Document Server

    Rando, Riccardo; Dazzi, Francesco; De Angelis, Alessandro; Dettlaff, Antonios; Dorner, Daniela; Fink, David; Fouque, Nadia; Grundner, Felix; Haberer, Werner; Hahn, Alexander; Hermel, Richard; Korpar, Samo; Mezek, Gašper Kukec; Maier, Ronald; Manea, Christian; Mariotti, Mosè; Mazin, Daniel; Mehrez, Fatima; Mirzoyan, Razmik; Podkladkin, Sergey; Reichardt, Ignasi; Rhode, Wolfgang; Rosier, Sylvie; Schultz, Cornelia; Stella, Carlo; Teshima, Masahiro; Wetteskind, Holger; Zavrtanik, Marko

    2015-01-01

    The Cherenkov Telescope Array (CTA) is the the next generation facility of imaging atmospheric Cherenkov telescopes; two sites will cover both hemispheres. CTA will reach unprecedented sensitivity, energy and angular resolution in very-high-energy gamma-ray astronomy. Each CTA array will include four Large Size Telescopes (LSTs), designed to cover the low-energy range of the CTA sensitivity ($\\sim$20 GeV to 200 GeV). In the baseline LST design, the focal-plane camera will be instrumented with 265 photodetector clusters; each will include seven photomultiplier tubes (PMTs), with an entrance window of 1.5 inches in diameter. The PMT design is based on mature and reliable technology. Recently, silicon photomultipliers (SiPMs) are emerging as a competitor. Currently, SiPMs have advantages (e.g. lower operating voltage and tolerance to high illumination levels) and disadvantages (e.g. higher capacitance and cross talk rates), but this technology is still young and rapidly evolving. SiPM technology has a strong pot...

  4. A Prototype Data Format for the Cherenkov Telescope Array: Regions Of Interest (ROI)

    CERN Document Server

    ,

    2015-01-01

    The Cherenkov Telescope Array (CTA) is a ground-based $\\gamma$-ray observatory that will observe the full sky in the energy range from 20 GeV to 100 TeV from facilities in both hemispheres. It is proposed to consist of more than 100 telescopes and the large amount of data produced will exceed the volume of current VHE Imaging Atmospheric Cherenkov Telescopes by $\\sim$two orders of magnitude. This volume of data represents a new challenge to the community, which is looking for new data formats to transfer and store the CTA data. One of the prototypes currently under study is the ROI (Regions Of Interest) file format for camera images. It can store only those pixels of a camera image that are close to the shower, thus removing the major part of the night sky background (NSB) while keeping all pixels that might belong to the shower. Simple on-the-fly compression is used to reduce the file size even further. Here, we explain the ROI prototype in detail and present preliminary results when applied to simulations.

  5. The IFAE/UAB and LUPM Raman LIDARs for Cherenkov Telescope Array Observatory

    CERN Document Server

    López-Oramas, A; Bigas, O Blanch; Boix, J; Da Deppo, V; Doro, M; Font, L; Garrido, D; Gaug, M; Martínez, M; Vasileiadis, G

    2013-01-01

    The Cherenkov Telescope Array (CTA) is the next generation of Imaging Atmospheric Cherenkov Telescopes. It will reach a sensitivity and an energy resolution with no precendent in very high energy gamma-ray astronomy. In order to achieve this goal, the systematic uncertainties derived from the atmospheric conditions shall be reduced to the minimum. Different instruments may help account for these uncertainties. The Barcelona IFAE/UAB (acronyms for Institut de F\\'isica d'Altes Energies and Universitat Aut\\`onoma de Barcelona, respectively) and the Montpellier LUPM (Laboratoire Univers et Particules de Montpellier) groups are building Raman LIDARs, devices which can reduce the systematic uncertainties in the reconstruction of the gamma-ray energies from 20$%$ down to 5$%$. The Raman LIDARs subject of this work have coaxial 1.8 m mirrors with a Nd-YAG laser each. A liquid light-guide collects the light at the focal plane and transports it to the readout system. We are developping a monochromator with the purpose ...

  6. Reconstructing the direction of reactor antineutrinos via electron scattering in Gd-doped water Cherenkov detector

    Energy Technology Data Exchange (ETDEWEB)

    Hellfeld, D. [Texas A & M Univ., College Station, TX (United States); Dazeley, S. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Bernstein, A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Marianno, C. [Texas A & M Univ., College Station, TX (United States)

    2015-11-25

    The potential of elastic antineutrino-electron scattering (ν¯e + e → ν¯e + e) in a Gd-doped water Cherenkov detector to determine the direction of a nuclear reactor antineutrino flux was investigated using the recently proposed WATCHMAN antineutrino experiment as a baseline model. The expected scattering rate was determined assuming a 13 km standoff from a 3.758 GWt light water nuclear reactor. Background was estimated via independent simulations and by appropriately scaling published measurements from similar detectors. Many potential backgrounds were considered, including solar neutrinos, misidentified reactor-based inverse beta decay interactions, cosmogenic radionuclide and water-borne radon decays, and gamma rays from the photomultiplier tubes, detector walls, and surrounding rock. The detector response was modeled using a GEANT4-based simulation package. The results indicate that with the use of low radioactivity PMTs and sufficient fiducialization, water-borne radon and cosmogenic radionuclides pose the largest threats to sensitivity. The directional sensitivity was then analyzed as a function of radon contamination, detector depth, and detector size. Lastly, the results provide a list of theoretical conditions that, if satisfied in practice, would enable nuclear reactor antineutrino directionality in a Gd-doped water Cherenkov detector approximately 10 km from a large power reactor.

  7. A template method for measuring the iron spectrum in cosmic rays with Cherenkov telescopes

    CERN Document Server

    Fleischhack, Henrike

    2015-01-01

    The energy-dependent abundance of elements in cosmic rays plays an important role in understanding their acceleration and propagation. Most current results are obtained either from direct measurements by balloon- or satellite-borne detectors, or from indirect measurements by air shower detector arrays on the Earth's surface. Imaging Atmospheric Cherenkov Telescopes (IACTs), used primarily for $\\gamma$-ray astronomy, can also be used for cosmic-ray physics. They are able to measure Cherenkov light emitted both by heavy nuclei and by secondary particles produced in air showers, and are thus sensitive to the charge and energy of cosmic ray particles with energies of tens to hundreds of TeV. A template-based method, which can be used to reconstruct the charge and energy of primary particles simultaneously from images taken by IACTs, will be introduced. Heavy nuclei, such as iron, can be separated from lighter cosmic rays with this method, and thus the abundance and spectrum of these nuclei can be measured in the ...

  8. Real-Time Analysis sensitivity evaluation of the Cherenkov Telescope Array

    CERN Document Server

    ,

    2015-01-01

    The Cherenkov Telescope Array (CTA), the new generation very high-energy gamma-ray observatory, will improve the flux sensitivity of the current Cherenkov telescopes by an order of magnitude over a continuous range from about 10 GeV to above 100 TeV. With tens of telescopes distributed in the Northern and Southern hemispheres, the large effective area and field of view coupled with the fast pointing capability make CTA a crucial instrument for the detection and understanding of the physics of transient, short-timescale variability phenomena (e.g. Gamma-Ray Bursts, Active Galactic Nuclei, gamma-ray binaries, serendipitous sources). The key CTA system for the fast identification of flaring events is the Real-Time Analysis (RTA) pipeline, a science alert system that will automatically detect and generate science alerts with a maximum latency of 30 seconds with respect to the triggering event collection and ensure fast communication to/from the astrophysics community. According to the CTA design requirements, the...

  9. Approximation of lateral distribution of atmospheric Cherenkov light at different observation levels. Comparison with previous results

    CERN Document Server

    Mishev, A; Stamenov, J

    2005-01-01

    This work summarizes the results presented at 29th International Cosmic Ray Conference in Pune India. Generally the aim of this work is to obtain the lateral distribution of the atmospheric Cherenkov light in extensive air showers produced by different primary particles in wide energy range and at several observation levels and to fit the obtained lateral distributions. Using one large detector and partially modified CORSIKA code version are obtained the lateral distributions of Cherenkov light flux densities at several observation levels for different particle primaries precisely at 536 g/cm2 Chacaltaya, 700 g/cm2 Moussala and 875 g/cm2 Kartalska field observation levels for hadronic primaries and gamma quanta in the energy range 1011 eV-1016 eV. On the basis of the solution of over-determined inverse problem the approximation of these distributions is obtained. The same model function for all the primaries is used and for the different observation levels. The different model parameters for the different pri...

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

    Science.gov (United States)

    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.

  11. The modeling of the nuclear composition measurement performance of the Non-Imaging CHErenkov Array (NICHE)

    CERN Document Server

    Krizmanic, John; Sokolsky, Pierre

    2013-01-01

    In its initial deployment, the Non-Imaging CHErenkov Array (NICHE)will measure the flux and nuclear composition of cosmic rays from below 10^16 eV to 10^18 eV by using measurements of the amplitude and time-spread of the air-shower Cherenkov signal to achieve a robust event-by-event measurement of Xmax and energy. NICHE will have sufficient area and angular acceptance to have significant overlap with TA/TALE, within which NICHE is located, to allow for energy cross-calibration. In order to quantify NICHE's ability to measure the cosmic ray nuclear composition, 4-component composition models were constructed based upon a poly-gonato model of J. Hoerandel using simulated Xmax distributions of the composite composition as a function of energy. These composition distributions were then unfolded into individual components via an analysis technique that included NICHE's simulated Xmax and energy resolution performance as a function of energy as well as the effects of finite event statistics. Details of the construc...

  12. The Cherenkov Telescope Array On-Site integral sensitivity: observing the Crab

    CERN Document Server

    Fioretti, Valentina; Schussler, Fabian

    2016-01-01

    The Cherenkov Telescope Array (CTA) is the future large observatory in the very high energy (VHE) domain. Operating from 20 GeV to 300 TeV, it will be composed of tens of Imaging Air Cherenkov Telescopes (IACTs) displaced in a large area of a few square kilometers in both the southern and northern hemispheres. The CTA/DATA On-Site Analysis (OSA) is the system devoted to the development of dedicated pipelines and algorithms to be used at the CTA site for the reconstruction, data quality monitoring, science monitoring and realtime science alerting during observations. The OSA integral sensitivity is computed here for the most studied source at Gamma-rays, the Crab Nebula, for a set of exposures ranging from 1000 seconds to 50 hours, using the full CTA Southern array. The reason for the Crab Nebula selection as the first example of OSA integral sensitivity is twofold: (i) this source is characterized by a broad spectrum covering the entire CTA energy range; (ii) it represents, at the time of writing, the standar...

  13. Status and Plans for the Array Control and Data Acquisition System of the Cherenkov Telescope Array

    CERN Document Server

    Oya, I; Schwanke, U; Wegner, P; Balzer, A; Berge, D; Borkowski, J; Camprecios, J; Colonges, S; Colome, J; Champion, C; Conforti, V; Gianotti, F; Flour, T Le; Lindemann, R; Lyard, E; Mayer, M; Melkumyan, D; Punch, M; Tanci, C; Schmidt, T; Schwarz, J; Tosti, G; Verma, K; Weinstein, A; Wiesand, S; Wischnewski, R

    2015-01-01

    The Cherenkov Telescope Array (CTA) is the next-generation atmospheric Cherenkov gamma-ray observatory. CTA will consist of two installations, one in the northern, and the other in the southern hemisphere, containing tens of telescopes of different sizes. The CTA performance requirements and the inherent complexity associated with the operation, control and monitoring of such a large distributed multi-telescope array leads to new challenges in the field of the gamma-ray astronomy. The ACTL (array control and data acquisition) system will consist of the hardware and software that is necessary to control and monitor the CTA arrays, as well as to time-stamp, read-out, filter and store -at aggregated rates of few GB/s- the scientific data. The ACTL system must be flexible enough to permit the simultaneous automatic operation of multiple sub-arrays of telescopes with a minimum personnel effort on site. One of the challenges of the system is to provide a reliable integration of the control of a large and heterogene...

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

    Science.gov (United States)

    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.

  15. Cosmic ray composition measurements and cosmic ray background free gamma-ray observations with Cherenkov telescopes

    CERN Document Server

    Neronov, A; Vovk, Ie; Mirzoyan, R

    2016-01-01

    Muon component of extensive air showers (EAS) initiated by cosmic ray particles carries information on the primary particle identity. We show that the muon content of EAS could be measured in a broad energy range from 10-100 TeV up to ultra-high-energy cosmic ray range using wide field-of-view imaging atmospheric Cherenkov telescopes observing strongly inclined or nearly horizontal EAS from the ground of from high altitude. Cherenkov emission from muons in such EAS forms a distinct component (halo or tail) of the EAS image in the telescope camera. We show that detection of the muon signal could be used to measure composition of the cosmic ray spectrum in the energy ranges of the knee, the ankle and of the Galactic-to-extragalactic transition. It could also be used to veto the cosmic ray background in gamma-ray observations. This technique provides a possibility for up to two orders of magnitude improvement of sensitivity for gamma-ray flux in the energy band above 10 PeV, compared to KASCADE-Grande, and an or...

  16. Developments of a new mirror technology for the Cherenkov Telescope Array

    CERN Document Server

    ,

    2015-01-01

    The Cherenkov Telescope Array (CTA) observatory for very high-energy gamma rays will consist of about a hundred of imaging atmospheric Cherenkov telescopes (IACTs) of different size with a total reflective area of about 10,000 m$^2$. Here we present a novel technology for the production of IACT mirrors that has been developed in the Institute of Nuclear Physics PAS in Krakow, Poland. The mirrors are made by cold-slumping of the front reflecting aluminium-coated panel and the rear panel interspaced with aluminium spacers. Each panel is built of two glass panels laminated with a layer of a fibreglass tissue in between for reinforcement of the structure against mechanical damage. The mirror structure is open and does not require a perfect sealing needed in closed-type designs. It prohibits water to be trapped inside and enables a proper ventilation of the mirror. Full-size hexagonal prototype mirrors produced for the medium-sized CTA telescopes will be presented together with the results of recent comprehensive ...

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

    Science.gov (United States)

    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.

  18. Using Raster Scans of Bright Stars to Measure the Relative Total Throughputs of Cherenkov Telescopes

    CERN Document Server

    Griffin, Sean

    2013-01-01

    Gamma-ray astronomy at energies in excess of 100 GeV is carried out using arrays of imaging Cherenkov telescopes. Each telescope comprises a large reflector, of order 10 m diameter, made of many mirror facets, and a camera consisting of a matrix of photomultiplier pixels. Differences in the total throughput between nominally identical telescopes, due to aging of the mirrors and PMTs and other effects, should be monitored to reduce possible systematic errors. One way to directly measure the throughput of such telescopes is to track bright stars and measure the photocurrents produced by their light falling on camera pixels. We have developed such a procedure using the four telescopes in the VERITAS array. We note the technique is general, however, and could be applied to other imaging Cherenkov experiments. For this measurement, a raster scan is performed on a single star such that its image is swept across the central pixels in the camera, thus providing a statistically robust set of measurements in a short pe...

  19. GAW - An Imaging Atmospheric Cherenkov Telescope with Large Field of View

    CERN Document Server

    Cusumano, G; Alberdi, A; Alvarez, M; Assis, P; Biondo, B; Bocchino, F; Brogueira, P; Caballero, J A; Carvajal, M; Castro-Tirado, A J; Catalano, O; Celi, F; Delgado, C; Di Cocco, G; Dominguez, A; Navas, J M Espino; Santo, M C Espirito; Gallardo, M I; García, J E; Giarrusso, S; Gómez, M; Gómez, J L; Gonçalves, P; Guerriero, M; La Barbera, A; La Rosa, G; Lozano, M; Maccarone, M C; Mangano, A; Martel, I; Massaro, E; Mineo, T; Moles, M; Pérez-Bernal, F; Peres-Torres, M A; Pimenta, M; Pina, A; Prada, F; Quesada, J M; Quintana, J M; Quintero, J R; Rodríguez, J; Russo, F; Sacco, B; Sanchez-Conde, M A; Segreto, A; Tome', B; Postigo, A de Ugarte; Vallania, P

    2007-01-01

    GAW, acronym for Gamma Air Watch, is a Research and Development experiment in the TeV range, whose main goal is to explore the feasibility of large field of view Imaging Atmospheric Cherenkov Telescopes. GAW is an array of three relatively small telescopes (2.13 m diameter) which differs from the existing and presently planned projects in two main features: the adoption of a refractive optics system as light collector and the use of single photoelectron counting as detector working mode. The optics system allows to achieve a large field of view (24x24 squared degrees) suitable for surveys of large sky regions. The single photoelectron counting mode in comparison with the charge integration mode improves the sensitivity by permitting also the reconstruction of events with a small number of collected Cherenkov photons. GAW, which is a collaboration effort of Research Institutes in Italy, Portugal and Spain, will be erected in the Calar Alto Observatory (Sierra de Los Filabres - Andalucia, Spain), at 2150 m a.s....

  20. Design of a Cherenkov telescope for the measurement of PCR composition above 1 PeV

    Directory of Open Access Journals (Sweden)

    Galkin V I

    2013-06-01

    Full Text Available The problem of PCR Composition at super high energies is far from being solved.EAS Cherenkov light spatial-angular distribution (CL SAD can yield important information on the primary mass. In order to use EAS CL SAD for the study of PCR composition one needs a set of imaging telescopes with the appropriate parameters supported by a dense net of fast optical detectors capable of measuring EAS Cherenkov light pulses. On the basis of full Monte-Carlo simulations the pixel size of imaging telescopes is optimized for a specific observation level ∼4km which is typical for the Eastern Pamir mountains. Another goal to be pursued by the new detector array is the search for ultra high energy gamma ray sources and this is where the imaging technique can help a lot. A simple criterion is introduced to recognize gamma-quanta against the proton background and its performance, once again analyzed using simulated events, sets certain limits to the pixel size.

  1. The design and performance of a prototype water Cherenkov optical time-projection chamber

    CERN Document Server

    Oberla, E

    2015-01-01

    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 $5.1\\times5.1$~cm$^2$ micro-channel plate photo-multipliers (MCP-PMT) and $6.7\\times6.7$~cm$^2$ 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 far side of the detector cylinder, effectively doubling 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 Ohm 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 op...

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

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y.T., E-mail: chenytao@ynu.edu.cn [Institut de Physique Nucléaire, IN2P3-CNRS, Université Paris-Sud, 91406 Orsay Cedex (France); Yunnan University, 650091 Kunming (China); La Taille, C. de [OMEGA (UMS 3605) - IN2P3/CNRS, Ecole Polytechnique, 91128 Palaiseau Cedex (France); Suomijärvi, T. [Institut de Physique Nucléaire, IN2P3-CNRS, Université Paris-Sud, 91406 Orsay Cedex (France); Cao, Z. [Institute of High Energy Physics, 100049 Beijing (China); Deligny, O. [Institut de Physique Nucléaire, IN2P3-CNRS, Université Paris-Sud, 91406 Orsay Cedex (France); Dulucq, F. [OMEGA (UMS 3605) - IN2P3/CNRS, Ecole Polytechnique, 91128 Palaiseau Cedex (France); Ge, M.M. [Yunnan University, 650091 Kunming (China); Lhenry-Yvon, I. [Institut de Physique Nucléaire, IN2P3-CNRS, Université Paris-Sud, 91406 Orsay Cedex (France); Martin-Chassard, G. [OMEGA (UMS 3605) - IN2P3/CNRS, Ecole Polytechnique, 91128 Palaiseau Cedex (France); Nguyen Trung, T.; Wanlin, E. [Institut de Physique Nucléaire, IN2P3-CNRS, Université Paris-Sud, 91406 Orsay Cedex (France); Xiao, G.; Yin, L.Q. [Institute of High Energy Physics, 100049 Beijing (China); Yun Ky, B. [Institut de Physique Nucléaire, IN2P3-CNRS, Université Paris-Sud, 91406 Orsay Cedex (France); Zhang, L. [Yunnan University, 650091 Kunming (China); Zhang, H.Y. [Tsinghua University, 100084 Beijing (China); Zhang, S.S.; Zhu, Z. [Institute of High Energy Physics, 100049 Beijing (China)

    2015-09-21

    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.

  3. The Single Mirror Small Sized Telescope For The Cherenkov Telescope Array

    CERN Document Server

    Heller, M; Porcelli, A; Pujadas, I Troyano; Zietara, K; della Volpe, D; Montaruli, T; Cadoux, F; Favre, Y; Aguilar, J A; Christov, A; Prandini, E; Rajda, P; Rameez, M; Bilnik, W; Blocki, J; Bogacz, L; Borkowski, J; Bulik, T; Frankowski, A; Grudzinska, M; Idzkowski, B; Jamrozy, M; Janiak, M; Kasperek, J; Lalik, K; Lyard, E; Mach, E; Mandat, D; Marszalek, A; Miranda, L D Medina; Michalowski, J; Moderski, R; Neronov, A; Niemiec, J; Ostrowski, M; Pasko, P; Pech, M; Schovanek, P; Seweryn, K; Sliusar, V; Skowron, K; Stawarz, L; Stodulska, M; Stodulski, M; Walter, R; Wiecek, M; Zagdanski, A

    2016-01-01

    The Small Size Telescope with Single Mirror (SST-1M) is one of the proposed types of Small Size Telescopes (SST) for the Cherenkov Telescope Array (CTA). About 70 SST telescopes will be part the CTA southern array which will also include Medium Sized Telescopes (MST) in its threshold configuration. Optimized for the detection of gamma rays in the energy range from 5 TeV to 300 TeV, the SST-1M uses a Davies-Cotton optics with a 4 m dish diameter with a field of view of 9 degrees. The Cherenkov light resulting from the interaction of the gamma-rays in the atmosphere is focused onto a 88 cm side-to-side hexagonal photo-detection plane. The latter is composed of 1296 hollow light guides coupled to large area hexagonal silicon photomultipliers (SiPM). The SiPM readout is fully digital readout as for the trigger system. The compact and lightweight design of the SST-1M camera offers very high performance ideal for gamma-ray observation requirement. In this contribution, the concept, design, performance and status of...

  4. Detection of Shielded Special Nuclear Material With a Cherenkov-Based Transmission Imaging System

    Science.gov (United States)

    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.

  5. Precision optical systems for the new generation of Ring Imaging Cherenkov detectors in high energy physics experiments

    International Nuclear Information System (INIS)

    High precision optical systems are required for the new generation of Ring Imaging Cherenkov detectors in high energy physics experiments. In the framework of the LHCb and COMPASS experiments, we have started an R and D programme to assess and to eventually overcome the limits of present technologies. Here, we present the available mirror technologies and discuss the optical and mechanical parameters

  6. Temporal signatures of the Cherenkov light induced by extensive air showers of cosmic rays detected with the Yakutsk array

    CERN Document Server

    Ivanov, A A

    2016-01-01

    We analyze temporal characteristics of signals from the wide field-of-view (WFOV) Cherenkov telescope (CT) detecting extensive air showers (EAS) of cosmic rays (CR) in coincidence with surface detectors of the Yakutsk array. Our aim is to reveal causal relationships between measured characteristics and physical properties of EAS.

  7. Performance of the Two Aerogel Cherenkov Detectors of the JLab Hall A Hadron Spectrometer

    CERN Document Server

    Marrone, S; Acha, A; Cisbani, E; Coman, M; Cusanno, F; De Jager, C W; De Leo, R; Gao, H; Garibaldi, F; Higinbotham, D W; Iodice, M; LeRose, J J; Macchia, D; Markowitz, P; Nappia, E; Palmisano, F; Urciuoli, G M; van der Werf, I; Xiang, H; Zhu, L Y

    2008-01-01

    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.

  8. Single-Mirror Small-Size Telescope structure for the Cherenkov Telescope Array

    CERN Document Server

    Niemiec, Jacek; Dyrda, Michał; Kochański, Wojciech; Ludwin, Jaromir; Stodulski, Marek; Ziółkowski, Paweł

    2013-01-01

    A single-mirror small-size (1M-SST) Davies-Cotton telescope has been proposed for the southern observatory of the Cherenkov Telescope Array (CTA) by a consortium of scientific institutions from Poland, Switzerland, and Germany. The telescope has a 4 m diameter reflector and will be equipped with a fully digital camera based on Geiger avalanche photodiodes (APDs). Such a design is particularly interesting for CTA because it represents a very simple, reliable, and cheap solution for a SST. Here we present the design and the characteristics of the mechanical structure of the 1M-SST telescope and its drive system. We also discuss the results of a finite element method analysis in order to demonstrate the conformance of the design with the CTA specifications and scientific objectives. In addition, we report on the current status of the construction of a prototype telescope structure at the Institute of Nuclear Physics PAS in Krakow.

  9. NectarCAM, a camera for the medium sized telescopes of the Cherenkov Telescope Array

    CERN Document Server

    Glicenstein, J-F

    2016-01-01

    NectarCAM is a camera proposed for the medium-sized telescopes of the Cherenkov Telescope Array (CTA) which covers the core energy range of ~100 GeV to ~30 TeV. It has a modular design and is based on the NECTAr chip, at the heart of which is a GHz sampling Switched Capacitor Array and 12-bit Analog to Digital converter. The camera will be equipped with 265 7-photomultiplier modules, covering a field of view of 8 degrees. Each module includes photomultiplier bases, high voltage supply, pre-amplifier, trigger, readout and Ethernet transceiver. The recorded events last between a few nanoseconds and tens of nanoseconds. The expected performance of the camera are discussed. Prototypes of NectarCAM components have been built to validate the design. Preliminary results of a 19-module mini-camera are presented, as well as future plans for building and testing a full size camera.

  10. Operating Water Cherenkov Detectors in high altitude sites for the Large Aperture GRB Observatory

    CERN Document Server

    Allard, D; Asorey, H; Barros, H; Bertou, X; Castillo, M; Chirinos, J M; De Castro, A; Flores, S; González, J; Berisso, M Gomez; Grajales, J; Guada, C; Day, W R Guevara; Ishitsuka, J; López, J A; Martínez, O; Melfo, A; Meza, E; Loza, P Miranda; Barbosa, E Moreno; Murrugarra, C; Núñez, L A; Ormachea, L J Otiniano; Pérez, G; Perez, Y; Ponce, E; Quispe, J; Quintero, C; Rivera, H; Rosales, M; Rovero, A C; Saavedra, O; Salazar, H; Tello, J C; Peralda, R Ticona; Varela, E; Velarde, A; Villaseñor, L; Wahl, D; Zamalloa, M A

    2009-01-01

    Water Cherenkov Detectors (WCD) are efficient detectors for detecting GRBs in the 10 GeV - 1 TeV energy range using the single particle technique, given their sensitivity to low energy secondary photons produced by high energy photons when cascading in the atmosphere. The Large Aperture GRB Observatory (LAGO) operates arrays of WCD in high altitude sites (above 4500 m a.s.l.) in Bolivia, Mexico and Venezuela, with planned extension to Peru. Details on the operation and stability of these WCD in remote sites with high background rates of particles will be detailed, and compared to simulations. Specific issues due to operation at high altitude, atmospheric effects and solar activity, as well as possible hardware enhancements will also be presented.

  11. Multianode Photo Multiplier Tubes as Photo Detectors for Ring Imaging Cherenkov Detectors

    CERN Document Server

    Muheim, F

    2003-01-01

    The 64-channel Multianode Photo Multiplier (MaPMT) has been evaluated as a candidate for the LHCb Ring Imaging Cherenkov (RICH) photo detectors. We present result from data taken with a 3x3 array of closely packed MaPMTs mounted onto the RICH 1 prototype vessel, exposed to charged particle beams at CERN, and read out at LHC speed. Using a LED light source, we have performed spatial light scans to study the light collection efficiency of the MaPMTs We have also measured the performance of the MaPMTs as a function of the applied high voltage. Different dynode resistor chains have been used to study the tubes at low gains. In addition, we have studied the behaviour of the MaPMT in magnetic fields.

  12. Status of the Medium-Sized Telescope for the Cherenkov Telescope Array

    CERN Document Server

    ,

    2015-01-01

    The Cherenkov Telescope Array (CTA), is an international project for the next generation ground- based observatory for gamma-ray astronomy in the energy range from 20 GeV to 300 TeV. The sensitivity in the core energy range will be dominated by up to 40 Medium-Sized Telescopes (MSTs). The MSTs, of Davies-Cotton type with a 12 m diameter reflector are currently in the prototype phase. A full-size mechanical telescope structure has been assembled in Berlin. The telescope is partially equipped with different mirror prototypes, which are currently being tested and evaluated for performances characteristics. A report concentrating on the details of the tele- scope structure, the drive assemblies and the optics of the MST prototype will be given.

  13. An astroclimatological study of candidate sites to host an imaging atmospheric Cherenkov telescope in Romania

    CERN Document Server

    Radu, A A; Curtef, V; Felea, D; Hasegan, D; Lucaschi, B; Manea, A; Popa, V; Ralita, I

    2011-01-01

    We come out in this paper with an astroclimatological study of meteorological data on relative humidity, dew point temperature, air temperature, wind speed, barometric air pressure, and sky cloudiness recorded at four Romanian locations (Baisoara, Rosia Montana, Semenic, Ceahlau) and Nordic Optical Telescope (NOT) located at Observatorio del Roque de Los Muchachos, in the Canary Islands. Long term trends of microclimates have been compared in order to identify the site-to-site variations. We have performed this analysis as part of a site testing campaign aimed at finding the best location for the establishment of a small Cherenkov telescope in Romania. The conditions at the Romanian sites have been compared to those of the Canary Islands considered as a reference. A statistical approach has been used for data analysis. Monthly and annual samples have been extracted from series of raw data for nighttime, daytime and entire day intervals. Percentage distributions of meteorological parameters, whose values excee...

  14. Progress in Monte Carlo design and optimization of the Cherenkov Telescope Array

    CERN Document Server

    Bernlöhr, K; Becherini, Y; Bigas, O Blanch; Bouvier, A; Carmona, E; Colin, P; Decerprit, G; Di Pierro, F; Dubois, F; Farnier, C; Funk, S; Hermann, G; Hinton, J A; Humensky, T B; Jogler, T; Khélifi, B; Kihm, T; Komin, N; Lenain, J -P; López-Coto, R; Maier, G; Mazin, D; Medina, M C; Moralejo, A; Moderski, R; Nolan, S J; Ohm, S; Wilhelmi, E de Oña; Parsons, R D; Arribas, M Paz; Pedaletti, G; Pita, S; Prokoph, H; Rulten, C B; Schwanke, U; Shayduk, M; Stamatescu, V; Vallania, P; Vorobiov, S; Wischnewski, R; Wood, M; Yoshikoshi, T; Zech, A

    2013-01-01

    The Cherenkov Telescope Array (CTA) will be an instrument covering a wide energy range in very-high-energy (VHE) gamma rays. CTA will include several types of telescopes, in order to optimize the performance over the whole energy range. Both large-scale Monte Carlo (MC) simulations of CTA super-sets (including many different possible CTA layouts as sub-sets) and smaller-scale simulations dedicated to individual aspects were carried out and are on-going. We summarize results of the prior round of large-scale simulations, show where the design has now evolved beyond the conservative assumptions of the prior round and present first results from the on-going new round of MC simulations.

  15. Detecting extended gamma-ray emission with the next generation Cherenkov telescopes

    CERN Document Server

    Alonso, M Fernandez; Rovero, A C

    2015-01-01

    Very high energy (VHE $>$100 GeV) gamma rays coming from blazars can produce pairs when interacting with the Extragalactic Background Light (EBL) and the Cosmic Microwave Background, generating an electromagnetic cascade. Depending on the Intergalactic Magnetic Field (IGMF) intensity, this cascade may result in an extended isotropic emission of photons around the source (halo), or in a broadening of the emission beam. The detection of these effects might lead to important constrains both on the IGMF intensity and the EBL density, quantities of great relevance in cosmological models. Using a Monte Carlo program, we simulate electromagnetic cascades for different values of the IGMF intensities and coming from a source similar to 1ES0229+200, a blazar with hard intrinsic spectrum at redshift $z=0.14$, which is an ideal distance for potentially observing the effect. We study the possible response of a generic future Cherenkov telescope using a simplified model for the sensitivity, effective area and angular resol...

  16. Actuator Development at IAAT for the Cherenkov Telescope Array Medium Size Telescopes

    CERN Document Server

    Diebold, S; Pühlhofer, G; Renner, S; Santangelo, A; Schanz, T; Tenzer, C

    2016-01-01

    The Cherenkov Telescope Array (CTA) will be the future observatory for TeV gamma-ray astronomy. In order to increase the sensitivity and to extend the energy coverage beyond the capabilities of current facilities, its design concept features telescopes of three different size classes. Based on the experience from H.E.S.S. phase II, the Institute for Astronomy and Astrophysics T\\"ubingen (IAAT) develops actuators for the mirror control system of the CTA Medium Size Telescopes (MSTs). The goals of this effort are durability, high precision, and mechanical stability under all environmental conditions. Up to now, several revisions were developed and the corresponding prototypes were extensively tested. In this contribution our latest design revision proposed for the CTA MSTs are presented.

  17. Extended performance gas Cherenkov detector for gamma-ray detection in high-energy density experiments

    Energy Technology Data Exchange (ETDEWEB)

    Herrmann, H. W., E-mail: herrmann@lanl.gov; Kim, Y. H.; Young, C. S.; Fatherley, V. E.; Lopez, F. E.; Oertel, J. A.; Batha, S. H. [Los Alamos National Laboratory, Los Alamos, New Mexico 87545 (United States); Malone, R. M. [National Security Technologies, LLC, Los Alamos, New Mexico 87544 (United States); Rubery, M. S.; Horsfield, C. J. [Atomic Weapons Establishment, Aldermaston, Berkshire RG7 4PR (United Kingdom); Stoeffl, W. [Lawrence Livermore National Laboratory, Livermore, California 94550 (United States); Zylstra, A. B. [Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139 (United States); Shmayda, W. T. [Laboratory for Laser Energetics, Rochester, New York 14623 (United States)

    2014-11-15

    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 C{sub 2}F{sub 6}, 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.

  18. Sensitivity of the High Altitude Water Cherenkov Experiment to observe Gamma-Ray Bursts

    Science.gov (United States)

    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.

  19. Flasher and muon-based calibration of the GCT telescopes proposed for the Cherenkov Telescope Array

    CERN Document Server

    Brown, Anthony M; Chadwick, Paula M; Daniel, Michael; White, Richard

    2015-01-01

    The GCT is a dual-mirror Small-Sized-Telescope prototype proposed for the Cherenkov Telescope Array. Calibration of the GCT's camera is primarily achieved with LED-based flasher units capable of producing $\\sim4$ ns FWHM pulses of 400 nm light across a large dynamic range, from 0.1 up to 1000 photoelectrons. The flasher units are housed in the four corners of the camera's focal plane and illuminate it via reflection from the secondary mirror. These flasher units are adaptable to allow several calibration scenarios to be accomplished: camera flat-fielding, linearity measurements (up to and past saturation), and gain estimates from both single pe measurements and from the photon statistics at various high illumination levels. In these proceedings, the performance of the GCT flashers is described, together with ongoing simulation work to quantify the efficiency of using muon rings as an end-to-end calibration for the optical throughput of the GCT.

  20. Gamma-Ray Burst Science in the Era of the Cherenkov Telescope Array

    CERN Document Server

    Inoue, Susumu; O'Brien, Paul T; Asano, Katsuaki; Bouvier, Aurelien; Carosi, Alessandro; Connaughton, Valerie; Garczarczyk, Markus; Gilmore, Rudy; Hinton, Jim; Inoue, Yoshiyuki; Ioka, Kunihito; Kakuwa, Jun; Markoff, Sera; Murase, Kohta; Osborne, Julian P; Otte, A Nepomuk; Starling, Rhaana; Tajima, Hiroyasu; Teshima, Masahiro; Toma, Kenji; Wagner, Stefan; Wijers, Ralph A M J; Williams, David A; Yamamoto, Tokonatsu; Yamazaki, Ryo

    2013-01-01

    We outline the science prospects for gamma-ray bursts (GRBs) with the Cherenkov Telescope Array (CTA), the next-generation ground-based gamma-ray observatory operating at energies above few tens of GeV. With its low energy threshold, large effective area and rapid slewing capabilities, CTA will be able to measure the spectra and variability of GRBs at multi-GeV energies with unprecedented photon statistics, and thereby break new ground in elucidating the physics of GRBs, which is still poorly understood. Such measurements will also provide crucial diagnostics of ultra-high-energy cosmic ray and neutrino production in GRBs, advance observational cosmology by probing the high-redshift extragalactic background light and intergalactic magnetic fields, and contribute to fundamental physics by testing Lorentz invariance violation with high precision. Aiming to quantify these goals, we present some simulated observations of GRB spectra and light curves, together with estimates of their detection rates with CTA. Alth...

  1. Geant4 based simulation of the Water Cherenkov Detectors of the LAGO Project

    CERN Document Server

    Calderón, R; Núñez, L A

    2015-01-01

    To characterize the signals registered by the different types of water Cherenkov detectors (WCD) used by the Latin American Giant Observatory (LAGO) Project, it is necessary to develop detailed simulations of the detector response to the flux of secondary particles at the detector level. These particles are originated during the interaction of cosmic rays with the atmosphere. In this context, the LAGO project aims to study the high energy component of gamma rays bursts (GRBs) and space weather phenomena by looking for the solar modulation of galactic cosmic rays (GCRs). Focus in this, a complete and complex chain of simulations is being developed that account for geomagnetic effects, atmospheric reaction and detector response at each LAGO site. In this work we shown the first steps of a GEANT4 based simulation for the LAGO WCD, with emphasis on the induced effects of the detector internal diffusive coating.

  2. Layered water Cherenkov detector for the study of ultra high energy cosmic rays

    Energy Technology Data Exchange (ETDEWEB)

    Letessier-Selvon, Antoine, E-mail: antoine.letessier-selvon@in2p3.fr [LPNHE, UPMC University Paris 6, UPD University Paris 7, CNRS/IN2P3, 4 Place Jussieu, FR-75252 Paris (France); Billoir, Pierre; Blanco, Miguel [LPNHE, UPMC University Paris 6, UPD University Paris 7, CNRS/IN2P3, 4 Place Jussieu, FR-75252 Paris (France); Mariş, Ioana C. [LPNHE, UPMC University Paris 6, UPD University Paris 7, CNRS/IN2P3, 4 Place Jussieu, FR-75252 Paris (France); University of Granada and C.A.F.P.E., Cuesta del Hospicio, 18071 Granada (Spain); Settimo, Mariangela [LPNHE, UPMC University Paris 6, UPD University Paris 7, CNRS/IN2P3, 4 Place Jussieu, FR-75252 Paris (France)

    2014-12-11

    We present a new design for the water Cherenkov detectors that are in use in various cosmic ray observatories. This novel design can provide a significant improvement in the independent measurement of the muonic and electromagnetic component of extensive air showers. From such multi-component data an event by event classification of the primary cosmic ray mass becomes possible. According to popular hadronic interaction models, such as EPOS-LHC or QGSJetII-04, the discriminating power between iron and hydrogen primaries reaches Fisher values of ∼2 or above for energies in excess of 10{sup 19}eV with a detector array layout similar to that of the Pierre Auger Observatory.

  3. Techniques And Results For The Calibration Of The MST Prototype For The Cherenkov Telescope Array

    CERN Document Server

    ,

    2016-01-01

    The next generation instrument for ground-based gamma-ray astronomy will be the Cherenkov Telescope Array (CTA), consisting of approximately 100 telescopes in three sizes, built on two sites with one each in the Northern and Southern Hemi- spheres. Up to 40 of these will be Medium Size Telescopes (MSTs) which will dominate sensitivity in the core energy range. Since 2012, a full size mechanical prototype for the modified 12 m Davies-Cotton design MST has been in operation in Berlin. This doc- ument describes the techniques which have been implemented to calibrate and optimise the mechanical and optical performance of the prototype, and gives the results of over three years of observations and measurements. Pointing calibration techniques will be discussed, along with the development of a bending model, and calibration of the CCD cameras used for pointing measurements. Additionally alignment of mirror segments using the Bokeh method is shown.

  4. Search for long-lived heavy charged particles using a ring imaging Cherenkov technique at LHCb

    Energy Technology Data Exchange (ETDEWEB)

    Aaij, R. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Adeva, B. [Universidad de Santiago de Compostela (Spain); Adinolfi, M. [Bristol Univ. (United Kingdom). H.H. Wills Physics Lab.; and others

    2015-12-15

    A search is performed for heavy long-lived charged particles using 3.0 fb{sup -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{sup 2}. (orig.)

  5. Search for long-lived heavy charged particles using a ring imaging Cherenkov technique at LHCb

    Energy Technology Data Exchange (ETDEWEB)

    Aaij, R. [European Organization for Nuclear Research (CERN), Geneva (Switzerland); Adeva, B. [Universidad de Santiago de Compostela, Santiago de Compostela (Spain); Adinolfi, M. [H.H. Wills Physics Laboratory, University of Bristol, Bristol (United Kingdom); Affolder, A. [Oliver Lodge Laboratory, University of Liverpool, Liverpool (United Kingdom); Ajaltouni, Z. [Clermont Université, Université Blaise Pascal, CNRS/IN2P3, LPC, Clermont-Ferrand (France); and others

    2015-12-15

    A search is performed for heavy long-lived charged particles using 3.0 fb{sup -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{sup 2}.

  6. Measurement of DT fusion and neutron-induced gamma-rays using gas Cherenkov Detector

    Science.gov (United States)

    Kim, Y.; Herrmann, H. W.; Evans, S.; Sedillo, T.; Langenbrunner, J. R.; Young, C. S.; Mack, J. M.; McEvoy, A.; Horsfield, C. J.; Rubery, M.; Ali, Z.; Stoeffl, W.

    2010-08-01

    A secondary gamma experiment was carried out using a Gas Cherenkov Detector (GCD) at the OMEGA laser facility. The primary experimental objective was to simulate neutron-induced secondary gamma production (n-γ) from a NIF implosion capsule, hohlraum, and thermo-mechanical package. The high-band width of the GCD enabled us to detect time delayed and Doppler broadened n-γ signals from five different puck materials (Si, SiO2, Al, Al2O3, Cu) placed near target chamber center. These measurements were used for MCNP & ITS ACCEPT code validation purposes. By a simple change of the GCD CO2 gas pressure the system can effectively eliminate signals induced by n-γ reactions and thereby allow quality measurements of DT fusion γ-rays that are produced at NIF (National Ignition Facility).

  7. Evaluation of Photo Multiplier Tube candidates for the Cherenkov Telescope Array

    Science.gov (United States)

    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.

  8. Astroclimatic Characterization of Vallecitos: A candidate site for the Cherenkov Telescope Array at San Pedro Martir

    CERN Document Server

    Tovmassian, Gagik; Ochoa, Jose Luis; Ernenwein, Jean-Pierre; Mandat, Dusan; Pech, Miroslav; Frayn, Ilse Plauchu; Colorado, Enrique; Murillo, Jose Manuel; Cesena, Urania; Garcia, Benjamin; Lee, William H; Bulik, Tomasz; Garczarczyk, Markus; Fruck, Christian; Costantini, Heide; Cieslar, Marek; Aune, Taylor; Vincent, Stephane; Carr, John; Serre, Natalia; Janecek, Petr; Haefner, Dennis

    2016-01-01

    We conducted an 18 month long study of the weather conditions of the Vallecitos, a proposed site in Mexico to harbor the northern array of the Cherenkov Telescope Array (CTA). It is located in Sierra de San Pedro Martir (SPM) a few kilometers away from Observatorio Astron\\'omico Nacional. The study is based on data collected by the ATMOSCOPE, a multi-sensor instrument measuring the weather and sky conditions, which was commissioned and built by the CTA Consortium. Additionally, we compare the weather conditions of the optical observatory at SPM to the Vallecitos regarding temperature, humidity, and wind distributions. It appears that the excellent conditions at the optical observatory benefit from the presence of microclimate established in the Vallecitos.

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

    CERN Document Server

    Dravins, Dainis

    2014-01-01

    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 observ...

  10. Characterization of the candidate site for the Cherenkov Telescope Array at the Observatorio del Teide

    CERN Document Server

    Puerto-Giménez, Irene; Barrena, Rafael; Castro, Julio; Doro, Michele; Font, Lluís; Rosillo, Miguel Nievas; Zamorano, Jaime

    2013-01-01

    The Spanish partners of the future Cherenkov Telescope Array (CTA) have selected a candidate site for the Northern installation of CTA, at 3 km from the Observatorio del Teide (OT), in the Canary Island of Tenerife. As the OT is a very well-characterized astronomical site. We focus here on differences between the publicly accessible measurements from the OT observatory and those obtained with instruments deployed at the candidate site. We find that the winds are generally softer at the candidate site, and the level of background light comparable to the Observatorio del Roque de los Muchachos (ORM) at La Palma in the B-band, while it is only slightly higher in the V-band.

  11. Cooling Tests of the NectarCAM camera for the Cherenkov Telescope Array

    CERN Document Server

    Moulin, E; Durand, D; Feirreira, O; Fesquet, M; Giebels, B; Glicenstein, J -F; Loiseau, D; Louis, F; Nunio, F; Rateau, S; consortia, CTA

    2015-01-01

    The NectarCAM is a camera proposed for the medium-sized telescopes in the framework of the Cherenkov Telescope Array (CTA), the next-generation observatory for very-high-energy gamma-ray astronomy. The cameras are designed to operate in an open environment and their mechanics must provide protection for all their components under the conditions defined for the CTA observatory. In order to operate in a stable environment and ensure the best physics performance, each NectarCAM will be enclosed in a slightly overpressurized, nearly air-tight, camera body, to prevent dust and water from entering. The total power dissipation will be ~7.7 kW for a 1855-pixel camera. The largest fraction is dissipated by the readout electronics in the modules. We present the design and implementation of the cooling system together with the test bench results obtained on the NectarCAM thermal demonstrator.

  12. Second large-scale Monte Carlo study for the Cherenkov Telescope Array

    CERN Document Server

    Hassan, T; Bernlör, K; Bregeon, J; Hinton, J; Jogler, T; Maier, G; Moralejo, A; Di Pierro, F; Wood, M

    2015-01-01

    The Cherenkov Telescope Array (CTA) represents the next generation of ground based instruments for Very High Energy gamma-ray astronomy. It is expected to improve on the sensitivity of current instruments by an order of magnitude and provide energy coverage from 20 GeV to more than 200 TeV. In order to achieve these ambitious goals Monte Carlo (MC) simulations play a crucial role, guiding the design of CTA. Here, results of the second large-scale MC production are reported, providing a realistic estimation of feasible array candidates for both Northern and Sourthern Hemisphere sites performance, placing CTA capabilities into the context of the current generation of High Energy $\\gamma$-ray detectors.

  13. Readout electronics for the Wide Field of view Cherenkov/Fluorescence Telescope Array

    Science.gov (United States)

    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.

  14. An Efficient Test Facility For The Cherenkov Telescope Array FlashCam Readout Electronics Production

    CERN Document Server

    Eisenkolb, F; Kalkuhl, C; Pühlhofer, G; Santangelo, A; Schanz, T; Tenzer, C

    2016-01-01

    The Cherenkov Telescope Array (CTA) is the planned next-generation instrument for ground-based gamma-ray astronomy, currently under preparation by a world-wide consortium. The FlashCam group is preparing a photomultiplier-based camera for the Medium Size Telescopes of CTA, with a fully digital Readout System (ROS). For the forthcoming mass production of a substantial number of cameras, efficient test routines for all components are currently under development. We report here on a test facility for the ROS components. A test setup and routines have been developed and an early version of that setup has successfully been used to test a significant fraction of the ROS for the FlashCam camera prototype in January 2016. The test setup with its components and interface, as well as first results, are presented here.

  15. Mass Composition Sensitivity of an Array of Water Cherenkov and Scintillation Detectors

    CERN Document Server

    Gonzalez, Javier G; Roth, Markus

    2011-01-01

    We consider a hybrid array composed of scintillation and water Cherenkov detectors designed to measure the cosmic ray primary mass composition at energies of about 1 EeV. We have developed a simulation and reconstruction chain to study the theoretical performance of such an array. In this work we investigate the sensitivity of mass composition observables in relation to the geometry of the array. The detectors are arranged in a triangular grid with fixed 750 m spacing and the configuration of the scintillator detectors is optimized for mass composition sensitivity. We show that the performance for composition determination can be compared favorably to that of Xmax measurements after the difference in duty cycles is considered.

  16. A facility to evaluate the focusing performance of mirrors for Cherenkov Telescopes

    Science.gov (United States)

    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.

  17. A Cherenkov-based Beam Loss Scintillator system for beam, background and online luminosity monitoring at the LHCb experiment at CERN

    CERN Document Server

    Alessio, F; Jacobsson, R

    2013-01-01

    The installation of a scintillator-based system in the LHCb cavern was initially proposed in order to observe injection problems around the LHCb interaction region. Thanks to the fact that LHCb had already developed a custom-made electronics board (BPIM) for the LHCb beam pickups and global LHCb timing monitoring, a complete, inexpensive but flexible and robust system was quickly developed and installed few cm from the beam pipe just in front of the LHCb VELO detector in time for the very first beams injected in the LHC. The current and final system – commonly referred to as Beam Loss Scintillator (BLS) system - ultimately played a central role in the fast beam, background and online luminosity monitoring at LHCb. In this paper, the features of the detector – based on quartz radiator and Cherenkov light - are described, including the functionalities that the system acquired during the proton-proton physics programmes in 2009- 2013 thanks to its flexibility, reliability and sensitivity to beam hal...

  18. SiPM detectors for the ASTRI project in the framework of the Cherenkov Telescope Array

    Science.gov (United States)

    Billotta, Sergio; Marano, Davide; Bonanno, Giovanni; Belluso, Massimiliano; Grillo, Alessandro; Garozzo, Salvatore; Romeo, Giuseppe; Timpanaro, Maria Cristina; Maccarone, Maria Concetta C.; Catalano, Osvaldo; La Rosa, Giovanni; Sottile, Giuseppe; Impiombato, Domenico; Gargano, Carmelo; Giarrusso, Salavtore

    2014-07-01

    The Cherenkov Telescope Array (CTA) is a worldwide new generation project aimed at realizing an array of a hundred ground based gamma-ray telescopes. ASTRI (Astrofisica con Specchi a Tecnologia Replicante Italiana) is the Italian project whose primary target is the development of an end-to-end prototype, named ASTRI SST-2M, of the CTA small size class of telescopes devoted to investigation of the highest energy region, from 1 to 100 TeV. Next target is the implementation of an ASTRI/CTA mini-array based on seven identical telescopes. Silicon Photo-Multipliers (SiPMs) are the semiconductor photosensor devices designated to constitute the camera detection system at the focal plane of the ASTRI telescopes. SiPM photosensors are suitable for the detection of the Cherenkov flashes, since they are very fast and sensitive to the light in the 300-700nm wavelength spectrum. Their drawbacks compared to the traditional photomultiplier tubes are high dark count rates, after-pulsing and optical cross-talk contributions, and intrinsic gains strongly dependent on temperature. Nonetheless, for a single pixel, the dark count rate is well below the Night Sky Background, the effects of cross-talk and afterpulses are typically lower than 20%, and the gain can be kept stable against temperature variations by means of adequate bias voltage compensation strategies. This work presents and discusses some experimental results from a large set of measurements performed on the SiPM sensors to be used for the ASTRI SST-2M prototype camera and on recently developed detectors demonstrating outstanding performance for the future evolution of the project in the ASTRI/CTA mini-array.

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

    Science.gov (United States)

    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.

  20. Status of the photomultiplier-based FlashCam camera for the Cherenkov Telescope Array

    Science.gov (United States)

    Pühlhofer, G.; Bauer, C.; Eisenkolb, F.; Florin, D.; Föhr, C.; Gadola, A.; Garrecht, F.; Hermann, G.; Jung, I.; Kalekin, O.; Kalkuhl, C.; Kasperek, J.; Kihm, T.; Koziol, J.; Lahmann, R.; Manalaysay, A.; Marszalek, A.; Rajda, P. J.; Reimer, O.; Romaszkan, W.; Rupinski, M.; Schanz, T.; Schwab, T.; Steiner, S.; Straumann, U.; Tenzer, C.; Vollhardt, A.; Weitzel, Q.; Winiarski, K.; Zietara, K.

    2014-07-01

    The FlashCam project is preparing a camera prototype around a fully digital FADC-based readout system, for the medium sized telescopes (MST) of the Cherenkov Telescope Array (CTA). The FlashCam design is the first fully digital readout system for Cherenkov cameras, based on commercial FADCs and FPGAs as key components for digitization and triggering, and a high performance camera server as back end. It provides the option to easily implement different types of trigger algorithms as well as digitization and readout scenarios using identical hardware, by simply changing the firmware on the FPGAs. The readout of the front end modules into the camera server is Ethernet-based using standard Ethernet switches and a custom, raw Ethernet protocol. In the current implementation of the system, data transfer and back end processing rates of 3.8 GB/s and 2.4 GB/s have been achieved, respectively. Together with the dead-time-free front end event buffering on the FPGAs, this permits the cameras to operate at trigger rates of up to several ten kHz. In the horizontal architecture of FlashCam, the photon detector plane (PDP), consisting of photon detectors, preamplifiers, high voltage-, control-, and monitoring systems, is a self-contained unit, mechanically detached from the front end modules. It interfaces to the digital readout system via analogue signal transmission. The horizontal integration of FlashCam is expected not only to be more cost efficient, it also allows PDPs with different types of photon detectors to be adapted to the FlashCam readout system. By now, a 144-pixel mini-camera" setup, fully equipped with photomultipliers, PDP electronics, and digitization/ trigger electronics, has been realized and extensively tested. Preparations for a full-scale, 1764 pixel camera mechanics and a cooling system are ongoing. The paper describes the status of the project.