arXiv subjects

J. A. Hinton

Publications and source records attributed to J. A. Hinton.

206 records · Page 12Linked to original sources

arXiv2002

Sensitivity of the Auger Observatory to ultra high energy photon composition through inclined showers

We report a calculation of the expected rate of inclined air showers induced by ultra high energy cosmic rays to be obtained by the Auger Southern Observatory assuming different mass compositions. We describe some features that can be used to distinguish photons at energies as high as 10$^{20}$ eV. The discrimination of photons at such energies will help to test some models of the origin of ultra-high-energy cosmic rays.

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arXiv2002

The STACEE-32 Ground Based Gamma-ray Detector

We describe the design and performance of the Solar Tower Atmospheric Cherenkov Effect Experiment detector in its initial configuration (STACEE-32). STACEE is a new ground-based gamma ray detector using the atmospheric Cherenkov technique. In STACEE, the heliostats of a solar energy research array are used to collect and focus the Cherenkov photons produced in gamma-ray induced air showers. The large Cherenkov photon collection area of STACEE results in a gamma-ray energy threshold below that of previous detectors.

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arXiv2002

Mass Composition of Cosmic Rays in the Range 2 x 10^17 - 3 x 10^18 Measured with Haverah Park Array

At the Haverah Park Array a number of air shower observables were measured that are relevant to the determination of the mass composition of cosmic rays. In this paper we discuss measurements of the risetime of signals in large area water-Cherenkov detectors and of the lateral distribution function of the water-Cherenkov signal. The former are used to demonstrate that the CORSIKA code, using the QGSJET98 model, gives an adequate description of the data with a low sensitivity, in this energy range, to assumptions about primary mass. By contrast the lateral distribution is sufficiently well measured that there is mass sensitivity. We argue that in the range 0.2-1.0 EeV the data are well represented with a bi-modal composition of 34+-2 % protons and the rest iron. We also discuss the systematic errors induced by the choice of hadronic model.

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arXiv2001

A new approach to inferring the mass composition of cosmic rays at energies above 10^18 eV

We describe a new approach to establishing the mass composition at high energies. Based on measuring both the vertical and inclined shower rates, it has the potential to distinguish heavy nuclei from light nuclei. We apply the method to Haverah Park data above 10^18 eV to show that, under the assumption that the Quark Gluon String Jet Model correctly describes the high energy interactions, the inclined shower measurements favour a light composition at energies above 10^19 eV. The same conclusion is obtained using a variety of assumptions about the cosmic ray spectrum. To the extent that precise spectral measurements will be possible by forthcoming experiments such as the Auger observatories, the method will further constrain data on composition of the ultra high energy cosmic rays.

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arXiv2001

Constraints on the Ultra High Energy Photon flux using inclined showers from the Haverah Park array

We describe a method to analyse inclined air showers produced by ultra high energy cosmic rays using an analytical description of the muon densities. We report the results obtained using data from inclined events (60^{\circ}<θ<80^{\circ}) recorded by the Haverah Park shower detector for energies above 10^19 eV. Using mass independent knowledge of the UHECR spectrum obtained from vertical air shower measurements and comparing the expected horizontal shower rate to the reported measurements we show that above 10^19 eV less than 48 % of the primary cosmic rays can be photons at the 95 % confidence level and above 4 X 10^19 eV less than 50 % of the cosmic rays can be photonic at the same confidence level. These limits place important constraints on some models of the origin of ultra high-energy cosmic rays.

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arXiv2001

The Status of the STACEE Observatory

The Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) is a ground-based instrument designed to study astrophysical sources of gamma radiation in the energy range of 50 to 500 GeV. STACEE uses an array of large heliostat mirrors at the National Solar Thermal Test Facility in Albuquerque, New Mexico, USA. The heliostats are used to collect Cherenkov light produced in gamma-ray air showers. The light is concentrated onto an array of photomultiplier tubes located near the top of a tower. The construction of STACEE started in 1997 and has been completed in 2001. During the 1998-99 observing season, we used a portion of the experiment, STACEE-32, to detect gamma-rays from the Crab Nebula. The completed version of STACEE uses 64 heliostat mirrors, having a total collection area of 2300 m^2. During the last year, we have also installed custom electronics for pulse delay and triggering, and 1 GHz Flash ADCs to read out the photomultiplier tubes. The commissioning of the full STACEE instrument is underway. Preliminary observations and simulation work indicate that STACEE will have an energy threshold below 70 GeV and a reach for extragalactic gamma-ray sources out to redshift of ~1.0. In this paper we describe the design and performance of STACEE.

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arXiv2000

New constraints from Haverah Park data on the photon and iron fluxes of UHE cosmic rays

Using data from inclined events ($60^{\circ}<θ<80^{\circ}$) recorded by the Haverah Park shower detector, we show that above 10^19 eV less than 30% of the primary cosmic rays can be photons or iron nuclei at the 95% confidence level. Above 4 10^19 eV less than 55% of the cosmic rays can be photonic at the same confidence level. These limits place important constraints on some models of the origin of ultra high energy cosmic rays. Details of two new events above 10^20 eV are reported.

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arXiv2000

The rate of cosmic ray showers at large zenith angles: a step towards the detection of ultra-high energy neutrinos by the Pierre Auger Observatory

It is anticipated that the Pierre Auger Observatory can be used to detect cosmic neutrinos of >10^19 eV that arrive at very large zenith angles. However showers created by neutrino interactions close to the detector must be picked out against a background of similar events initiated by cosmic ray nuclei. As a step towards understanding this background, we have made the first detailed analysis of air showers recorded at Haverah Park (an array which used similar detectors to those planned for the Auger Observatory) with zenith angles above 60 degs. We find that the differential shower rate from 60 degs to 80 degs. can be predicted accurately when we adopt the known primary energy spectrum above 10^17 eV and assume the QGSJET model and proton primaries. Details of the calculation are given.

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