22 research outputs found

    Gamma‐ray optical counterpart search experiment (GROCSE)

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    The requirements of a gamma‐ray burst optical counterpart detector are reviewed. By taking advantage of real‐time notification of bursts, new instruments can make sensitive searches while the gamma‐ray transient is still in progress. A wide field of view camera at Livermore National Laboratories has recently been adapted for detecting GRB optical counterparts to a limiting magnitude of 8. A more sensitive camera, capable of reaching mv=14, is under development. © 1994 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87629/2/633_1.pd

    Results from GROCSE I: A real-time search for gamma ray burst optical counterparts

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    The GROCSE I experiment (Gamma-Ray Optical Counterpart Search Experiment) is a rapid slewing wide field of view optical telescope at Lawrence Livermore National Laboratory, which responds to triggers from the BATSE GRB data telemetry stream that have been processed and distributed by the BACODINE network. GROCSE I has been in continuous automated operation since January 1994. As of October 1995, sky images for 22 GRB triggers have been recorded, in some cases while the burst was still in progress. The preliminary analysis of eight of these events are presented here. No optical counterparts have yet been detected. Limits for optical emission are given. © 1996 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87367/2/671_1.pd

    Gamma ray burst optical counterpart search experiment (GROCSE)

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    GROCSE (Gamma-Ray Optical Counterpart Search Experiment) is a system of automated telescopes that search for simultaneous optical activity associated with gamma ray bursts in response to real-time burst notifications provided by the BATSE/BACODINE network. The first generation system, GROCSE I, is sensitive down to MV ∼ 8.5MV∼8.5 and requires an average of 12 seconds to obtain the first images of the gamma ray burst error box defined by the BACODINE trigger. The collaboration is now constructing a second generation system which has a 4 second slewing time and can reach MV ∼ 14MV∼14 with a 5 second exposure. GROCSE II consists of 4 cameras on a single mount. Each camera views the night sky through a commercial Canon lens (f/1.8,(f/1.8, focal length 200 mm) and utilizes a 2K×2K2K×2K Loral CCD. Light weight and low noise custom readout electronics were designed and fabricated for these CCDs. The total field of view of the 4 cameras is 17.6×17.6°.17.6×17.6°. GROCSE II will be operating by the end of 1995. In this paper, we present an overview of the GROCSE system and the results of measurements with a GROCSE II prototype unit. © 1996 American Institute of Physics.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87369/2/861_1.pd

    Neutrino astrophysics with IMB: past, present, and future

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    A burst of eight neutrino interactions occurring over a six second interval had been observed with the IMB detector. The closeness in time of the burst to the optical discovery of Supernova 1987a suggests that the neutrinos originated from stellar collapse. The characteristics of the burst are reviewed together with a recently completed reevaluation of many aspects of the detector's response. Efforts underway to discover past and future supernovae are also briefly discussed.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/27392/1/0000423.pd

    Experimental limits on nucleon decay and ΔB=2 processes

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    Results from the IMB collabration to detect possible proton decay in a salt mine near Cleveland, Ohio are presented. Detection apparatus is described.(AIP)Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/87900/2/1_1.pd

    Indications of flow near maximum compression in layered deuterium-tritium implosions at the National Ignition Facility

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    An accurate understanding of burn dynamics in implosions of cryogenically layered deuterium (D) and tritium (T) filled capsules, obtained partly through precision diagnosis of these experiments, is essential for assessing the impediments to achieving ignition at the National Ignition Facility. We present measurements of neutrons from such implosions. The apparent ion temperatures T[subscript ion] are inferred from the variance of the primary neutron spectrum. Consistently higher DT than DD T[subscript ion] are observed and the difference is seen to increase with increasing apparent DT T[subscript ion]. The line-of-sight rms variations of both DD and DT T[subscript ion] are small, ∼ 150 eV, indicating an isotropic source. The DD neutron yields are consistently high relative to the DT neutron yields given the observed T[subscript ion]. Spatial and temporal variations of the DT temperature and density, DD-DT differential attenuation in the surrounding DT fuel, and fluid motion variations contribute to a DT T[subscript ion] greater than the DD T[subscript ion], but are in a one-dimensional model insufficient to explain the data. We hypothesize that in a three-dimensional interpretation, these effects combined could explain the results.Lawrence Livermore National Laboratory (Contract No. DE-AC52- 07NA27344

    Limits on the flux of energetic neutrinos from the sun

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    A number of authors have proposed mechanisms by which the sun could be a strong source of energetic neutrinos. We search for an excess signal of penetrating neutral particles from the direction of the sun. We employ two data samples. One sample studies energies from 400 MeV to 2 GeV. The other studies v[mu] interactions above 2 GeV where the atmospheric background is lower. Our results are compared with the general background of atmospheric neutrinos from other directions. No significant excess has been found. These results can be used to set limits on possible dark matter candidates.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/26733/1/0000284.pd
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