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The expected rates of X-ray flashes from GRBs in ROSAT and preliminary search results

Description: The recent long (up to days) and relatively bright soft X-ray afterglows from GRBs detected by BeppoSAX raise the possibility of detecting similar events in the ROSAT database. The authors perform detailed calculations on the expected number of ROSAT events based on the extended halo scenario. They use the realistic ROSAT capabilities and the actual exposure time on bright nearby galaxies. They find that the expected number of x-ray events is quite low, {approximately} 1, and depends on the peak x-ray luminosity. Thus a nondetection of such events from nearby galaxies (within 12 Mpc) can not rule out most of the viable halo models. They also present the preliminary search results from the ROSAT PSPC database.
Date: December 1, 1998
Creator: Li, H.; Sun, X. & Fenimore, E.E.
Partner: UNT Libraries Government Documents Department

Purified water quality study

Description: Argonne National Laboratory (HEP) is examining the use of purified water for the detection medium in cosmic ray sensors. These sensors are to be deployed in a remote location in Argentina. The purpose of this study is to provide information and preliminary analysis of available water treatment options and associated costs. This information, along with the technical requirements of the sensors, will allow the project team to determine the required water quality to meet the overall project goals.
Date: April 3, 2000
Creator: Spinka, H. & Jackowski, P.
Partner: UNT Libraries Government Documents Department

A continuous watch of the northern sky above 40 TeV with the CYGNUS array

Description: This is the final report of a three-year, Laboratory Directed Research and Development (LDRD) project at the Los Alamos National Laboratory (LANL). The aim of the project has been to continuously monitor the northern sky for transient high-energy gamma-ray emission from astrophysical sources. Potential objects of such emission include gamma-ray bursts and flares from active galaxies. At the start of this project, the CYGNUS extensive air shower array was used for the monitoring; CYGNUS has an energy threshold of {approximately}40 TeV. In August, 1996, the CYGNUS data-acquisition computer suffered a fatal hardware problem so data-taking with the array ended. The Milagrito detector, which is much more sensitive than CYGNUS, started taking data in February 1997 and has continued the sky monitoring. The authors are presently honing reconstruction algorithms for Milagrito. When this is complete, the data taken since February will be analyzed for transient emission.
Date: November 1, 1998
Creator: Haines, T.J.; Miller, R. & Sinnis, C.
Partner: UNT Libraries Government Documents Department

Observation of the moon shadow in deep underground muon flux.

Description: A shadow of the moon, with a statistical significance of 5{sigma}, has been observed in the underground muon flux at a depth of 2090 mwe using the Soudan 2 detector. The angular resolution of the detector is well described by a Gaussian with {sigma} {le}0.3{degree}. The position of the shadow confirms the alignment of the detector to better than 0.15{degree}. This alignment has remained stable during 10 years of data taking from 1989 through 1998.
Date: June 22, 1999
Creator: Allison, W. W. M.; Alner, G. J.; Ayres, D. S.; Cobb, J. H.; Fields, T. H.; Goodman, M. C. et al.
Partner: UNT Libraries Government Documents Department

Neutrino induced muons in Soudan 2.

Description: The neutrino-induced muon rate underground has been measured at Soudan 2. To discriminate from the intense background of atmospheric muons we consider only the through-going muons which originate from horizontal direction ({minus}0.14 < cos{theta} < 0.14). We calculate the horizontal, neutrino-induced muon rate at Soudan 2 from an exposure of 1.23 x 10{sup 8} s as {Phi}{sub {nu}{mu}} = (3.45 {+-} 0.52 {+-} 0.61) x 10{sup {minus}13} (cm{sup 2} sr s){sup {minus}1}.
Date: June 23, 1999
Creator: DeMuth, D. M. & Collaboration, Soudan 2
Partner: UNT Libraries Government Documents Department

Experimental overview of axion searches

Description: Experimental methods to search for the ``invisible axion`` (f{sub a} {much_gt} 250 GeV) are reviewed. The report focuses on the axion-photon coupling, both for laboratory experiments as well as those looking for stellar or cosmologically produced axions. The conclusion is that while the axion-photon mixing in principle would permit laboratory axion searches which are broadband in mass, in fact no such experiment could have the sensitivity to the axion, where m{sub afa} {approx} m{sub {pi}f{pi}}. The only experiments which promise to have any chance to find the axion are the microwave cavity experiments, which presume axions to constitute our galactic halo dark matter. The conversion of axions into a monochromatic microwave signal in a resonant circuit affords the experiment the extraordinary sensitivity required to see the axion, at the expense of being narrow-band in mass, i.e. a tuning experiment. Two such efforts are underway in the world.
Date: June 28, 1995
Creator: van Bibber, K.
Partner: UNT Libraries Government Documents Department

Atmospheric neutrinos in Soudan 2.

Description: The value and zenith angle dependence of the atmospheric neutrino flavor ratio is interpreted as evidence for neutrino oscillations. The latest values from the Soudan 2 detector are presented. From 4.2 kt-years fiducial exposure, Soudan 2 measures R = 0.66 {+-} 0.11(stat) + 0.05--0.06(syst). Using a subset of the data with the best angular resolution, they plot the L/E distribution and use this to find the allowed region in oscillation parameter space. Their fit suggests that delta m-squared is greater than 10{sup {minus}3} eV{sup 2} at 90% CL.
Date: June 22, 1999
Creator: Goodman, M. C. & Collaboration, The Soudan 2
Partner: UNT Libraries Government Documents Department

Nucleon decay in Soudan 2.

Description: The Soudan 2 detector is used to search for evidence of nucleon decay. Particular emphasis is put on searches for modes with multiple-charged particles in the final state, and for modes suggested by super-symmetric theories.
Date: June 22, 1999
Creator: Goodman, M. C.
Partner: UNT Libraries Government Documents Department

The Pierre Auger project

Description: The Pierre Auger project is a broadly based international effort to make a detailed study of cosmic rays at the highest energies. Two air shower detectors are proposed, one to be placed in the Northern Hemisphere and one in the Southern Hemisphere. Each installation will consist of an array of 1600 particle detectors spread over 3000 km{sup 2} with a solid angle acceptance of 2 sr for cosmic ray air showers. Eah installation will also have an atmospheric fluorescence detector viewing the volume above the surface array. These two air shower detector techniques working together form a powerful instrument for the proposed research. The objectives of the Pierre Auger project are to measure the arrival direction, energy, and mass composition of 60 events per year above an energy of 10{sup 20} eV and 6000 events per year above 10{sup 19} eV. A collaboration is now being formed with the goal of having the Pierre Auger observatory in operation by 2001.
Date: January 1, 1996
Creator: Mantsch, P.M.
Partner: UNT Libraries Government Documents Department

Results from the CACTI experiment: Air-Cerenkov and particle measurements of PeV air showers at Los Alamos

Description: An array of six wide angle Cerenkov detectors was constructed amongst the scintillator and muon detectors of the CYGNUS II array at Los Alamos National Laboratory to investigate cosmic ray composition in the PeV region through measurements of the shape of Cerenkov lateral distributions. Data were collected during clear, moonless nights over three observing periods in 1995. Estimates of depths of shower maxima determined from the recorded Cerenkov lateral distributions align well with existing results at higher energies and suggest a mixed to heavy composition in the PeV region with no significant variation observed around the knee. The accuracy of composition determination is limited by uncertainties in the expected levels of depth of maximum predicted using different Monte-Carlo shower simulation models.
Date: July 1, 1997
Creator: Paling, S.; Hillas, A.M. & Berley, D.
Partner: UNT Libraries Government Documents Department

Milagro Contributions to XXVI International Cosmic Ray Conference

Description: Milagrito, a prototype for the Milagro detector, operated for 15 months in 1997--8 and collected 8.9 x 10{sup 9} events. It was the first extensive air shower (EAS) array sensitive to showers initiated by primaries with energy below 1 TeV. The shadows of the sun and moon observed with cosmic rays can be used to study systematic pointing shifts and measure the angular resolution of EAS arrays. Below a few TeV, the paths of cosmic rays coming toward the earth are bent by the helio- and geo-magnetic fields. This is expected to distort and displace the shadows of the sun and the moon. The moon shadow, offset from the nominal (unreflected) position, has been observed with high statistical significance in Milagrito. This can be used to establish energy calibrations, as well as to search for the anti-matter content of the VHE cosmic ray flux. The shadow of the sun has also been observed with high significance.
Date: August 1, 1999
Creator: Hoffman, C.M.; Haines, T.J.; Sinnis, G.; Miller, R.S. & Thompson, N.T.
Partner: UNT Libraries Government Documents Department

Detection of cosmic ray tracks using scintillating fibers and position sensitive multi-anode photomultipliers

Description: This experiment demonstrates detection of cosmic ray tracks by using Scintillating fiber planes and multi-anode photomultipliers (MA-PMTs). In a laboratory like this, cosmic rays provide a natural source of high-energy charged particles which can be detected with high efficiency and with nanosecond time resolution.
Date: February 1, 1998
Creator: Atac, M.; Streets, J. & Wilcer, N.
Partner: UNT Libraries Government Documents Department

The energy spectrometer for particles (ESP): Instrument description and orbital performance

Description: The ESP detector is functionally described, along with the pertinent orbital and spin properties of the spacecraft that supports it. The phoswiched plastic/BGO scintillators sensor design, electronic implementation, and resulting data types are recounted, and the ground calibration procedures are reported. Several illustrative examples of data are given, including the solar proton event of 29 September 1989, and the nearly periodic episodes of high relativistic electron flux that are associated with solar coronal holes which have been a dominant feature of the space weather over the past few years.
Date: December 31, 1994
Creator: Meier, M.; Belian, D.; Cayton, T.; Christensen, R.; Garcia, B.; Grace, K. et al.
Partner: UNT Libraries Government Documents Department

Time profiles and pulse structure of bright, long gamma-ray bursts using BATSE TTS data

Description: The time profiles of many gamma-ray bursts observed by BATSE consist of distinct pulses, which offer the possibility of characterizing the temporal structure of these bursts using a relatively small set of pulse-shape parameters. This pulse analysis has previously been performed on some bright, long bursts using binned data, and on some short bursts using BATSE Time-Tagged Event (TTE) data. The BATSE Time- to-Spill (TTS) burst data records the times required to accumulate a fixed number of photons, giving variable time resolution. The spill times recorded in the TTS data behave as a gamma distribution. We have developed an interactive pulse-fitting program using the pulse model of Norris et al. and a maximum-likelihood fitting algorithm to the gamma distribution of the spill times. We then used this program to analyze a number of bright, long bursts for which TTS data is available. We present statistical information on the attributes of pulses comprising these bursts.
Date: April 1, 1996
Creator: Lee, A.; Bloom, E. & Scargle, J.
Partner: UNT Libraries Government Documents Department

Seasonal variations in Soudan 2.

Description: Seasonal Variations in an underground detector may be a signature for Dark Matter. The Soudan 2 detector searches for nucleon decay and atmospheric neutrinos. The trigger rate is about 0.5 Hertz. It is dominated by approximately equal numbers of atmospheric muons and low level radioactivityy. The muon rate has a seasonal variation of {+-}2%, which is consistent with a similar effect at MACRO. The MACRO effect has been correlated with temperature in the upper atmosphere. Our trigger rate has a seasonal variation of {+-}15% which we believe is due to radon in the mine, and variations in air flow with outside temperature.
Date: June 23, 1999
Creator: Goodman, M. C. & Collaboration, Soudan 2
Partner: UNT Libraries Government Documents Department

Cosmic ray sun shadow in Soudan 2 underground muon flux.

Description: The absorption of cosmic rays by the sun produces a shadow at the earth. The angular offset and broadening of the shadow are determined by the magnitude and structure of the interplanetary magnetic field (IPMF) in the inner solar system. The authors report the first measurement of the solar cosmic ray shadow by detection of deep underground muon flux in observations made during the entire ten-year interval 1989 to 1998. The sun shadow varies significantly during this time, with a 3.3{sigma} shadow observed during the years 1995 to 1998.
Date: June 23, 1999
Creator: Allison, W. W. M.; Alner, G. J.; Ayres, D. S.; Barrett, W. L.; Bode, C.; Fields, T. H. et al.
Partner: UNT Libraries Government Documents Department

Search for neutrinos from active galactic nuclei in Soudan 2.

Description: Models for AGN neutrino production suggest a measurable muon flux in underground detectors in this paper we comment on neutrino point sources and discuss our methods for determining an upper limit on the intensity of horizontal, neutrino induced muons with energy above 1 TeV at the Soudan 2 detector. We set a limit of 1.8 x 10{sup {minus}13} (cm{sup 2} sr s){sup {minus}} for detecting 5 TeV {nu}-induced muons from AGN.
Date: June 22, 1999
Creator: DeMuth, D. M. & Collaboration, The Soudan 2
Partner: UNT Libraries Government Documents Department

A space bourne crystal diffraction telescope for the energy range of nuclear transitions

Description: Recent experimental work of the Toulouse-Argonne collaboration has opened for perspective of a focusing gamma-ray telescope operating in the energy range of nuclear transitions, featuring unprecedented sensitivity, angular and energy resolution. The instrument consists of a tunable crystal diffraction lens situated on a stabilized spacecraft, focusing gamma-rays onto a small array of Germanium detectors perched on an extendible boom. While the weight of such an instrument is less than 500 kg, it features an angular resolution of 15 in., an energy resolution of 2 keV and a 3 {sigma} narrow line sensitivity of a few times 10{sup {minus}7} photons s{sup {minus}1} cm{sup {minus}2} (10{sup 6} sec observation). This instrumental concept permits observation of any identified source at any selected line-energy in a range of typically 200 keV to 1300 keV. The resulting ``sequential`` operation mode makes sites of explosive nucleosynthesis natural scientific objectives for such a telescope: the nuclear lines of extragalactic supernovae ({sup 56}Ni, {sup 44}Ti, {sup 60}Fe) and galactic novae (p{sup {minus}}p{sup +} line, {sup 7}Be) are accessible to observation, one at a time, due to the erratic appearance and the sequence of half-lifes of these events. Other scientific objectives, include the narrow 511 keV line from galactic broad class annihilators (such as 1E1740-29, nova musca) and possible redshifted annihilation lines from AGN`s.
Date: October 1, 1995
Creator: von Ballmoos, P.; Naya, J.E.; Albernhe, F.; Vedrenne, G.; Smither, R.K.; Faiz, M. et al.
Partner: UNT Libraries Government Documents Department

Dark matter axions `96

Description: This report discusses why axions have been postulated to exist, what cosmology implies about their presence as cold dark matter in the galactic halo, how axions might be detected in cavities wherein strong magnetic fields stimulate their conversion into photons, and relations between axions` energy spectra and galactic halos` properties.
Date: December 31, 1996
Creator: Sikivie, P.
Partner: UNT Libraries Government Documents Department

X-ray flashes in ROSAT PSPC data

Description: The authors find 24 short (200--2,500s) X-ray flashes from all the ROSAT Position Sensitive Proportional Counter (PSPC) observations above galactic latitude 30 degrees ({approximately} 9.6 Msec) and some observations toward low latitudes ({approximately} 2.4 Msec). The brightest flash is quite extraordinary. Its flux rises from nondetection by a factor of > 200 in less than 100 sec. Its spectrum can be fitted either by a thermal plasma model with kT {ge} 2.4 keV, or by a single power-law with the photon number index of {approx} {minus}1.7. Photon statistics are not sufficient to obtain spectra for other flashes. The flash event fields can vary from optically crowded regions to blank fields. Although eight flashes are found from observations from nearby galaxies, and three of them are within the optical extent of their corresponding galaxies, they could not statistically establish that there are two different populations between nearby galaxies and control fields.
Date: December 1, 1998
Creator: Sun, X.; Li, H.; Fenimore, E.E. & Wang, Q.D.
Partner: UNT Libraries Government Documents Department

Response of the D0 calorimeter to cosmic ray muons

Description: The D0 Detector at the Fermi National Accelerator Laboratory is a large multi-purpose detector facility designed for the study of proton-antiproton collision products at the center-of-mass energy of 2 TeV. It consists of an inner tracking volume, hermetic uranium/liquid argon sampling calorimetry, and an outer 4{pi} muon detector. In preparation for our first collider run, the collaboration organized a Cosmic Ray Commissioning Run, which took place from February - May of 1991. This thesis is a detailed study of the response of the central calorimeter to cosmic ray muons as extracted from data collected during this run.
Date: October 1, 1992
Creator: Kotcher, J.
Partner: UNT Libraries Government Documents Department