Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userGeomagnetic effects on atmospheric Cerenkov images
150
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
Atmospheric Cerenkov telescopes are used to detect electromagnetic showers from primary gamma rays of energy ~300 GeV - ~10 TeV and to discriminate these from cascades due to hadrons using the Cerenkov images. The geomagnetic field affects the development of showers and is shown to diffuse and distort the images. When the component of the field normal to the shower axis is sufficiently large (> 0.4 G) the performance of gamma ray telescopes may be affected, although corrections should be possible.
rate research
Read More
Atmospheric Cerenkov telescopes are used to detect electromagnetic showers from primary gamma rays of energy > 300 GeV and to discriminate these from cascades due to hadrons using the shape and orientation of the Cerenkov images. The geomagnetic field affects the development of showers and diffuses and distorts the images. When the component of the field normal to the shower axis is sufficiently large (> 0.4 G) the performance of gamma ray telescopes may be affected.
Three different analysis techniques for Atmospheric Imaging System are presented. The classical Hillas parameters based technique is shown to be robust and efficient, but more elaborate techniques can improve the sensitivity of the analysis. A comparison of the different analysis techniques shows that they use different information for gamma-hadron separation, and that it is possible to combine their qualities.
The hunt for cosmic TeV particle accelerators is prospering through Imaging Atmospheric Cerenkov Telescopes. We face challenges such as low light levels and MHz trigger rates, and the need to distinguish between particle air showers stemming from primary gamma rays and those due to the hadronic cosmic ray background. Our test beam is provided by the Crab Nebula, a steady accelerator of particles to energies beyond 20 TeV. Highly variable gamma-ray emission, coincident with flares at longer wavelengths, is revealing the particle acceleration mechanisms at work in the relativistic jets of Active Galaxies. These 200 GeV to 20 TeV photons propagating over cosmological distances allow us to place a limit on the infra-red background linked to galaxy formation and, some speculate, to the decay of massive relic neutrinos. Gamma rays produced in neutralino annihilation or the evaporation of primordial black holes may also be detectable. These phenomena and a zoo of astrophysical objects will be the targets of the next generation multi-national telescope facilities.
A comprehensive study on the atmospheric neutrino flux in the energy region from sub-GeV up to several TeV using the Super-Kamiokande water Cherenkov detector is presented in this paper. The energy and azimuthal spectra of the atmospheric ${ u}_e+{bar{ u}}_e$ and ${ u}_{mu}+{bar{ u}}_{mu}$ fluxes are measured. The energy spectra are obtained using an iterative unfolding method by combining various event topologies with differing energy responses. The azimuthal spectra depending on energy and zenith angle, and their modulation by geomagnetic effects, are also studied. A predicted east-west asymmetry is observed in both the ${ u}_e$ and ${ u}_{mu}$ samples at 8.0 {sigma} and 6.0 {sigma} significance, respectively, and an indication that the asymmetry dipole angle changes depending on the zenith angle was seen at the 2.2 {sigma} level. The measured energy and azimuthal spectra are consistent with the current flux models within the estimated systematic uncertainties. A study of the long-term correlation between the atmospheric neutrino flux and the solar magnetic activity cycle is also performed, and a weak indication of a correlation was seen at the 1.1 {sigma} level, using SK I-IV data spanning a 20 year period. For particularly strong solar activity periods known as Forbush decreases, no theoretical prediction is available, but a deviation below the typical neutrino event rate is seen at the 2.4 {sigma} level.
We propose a novel approach for the determination of the nature of ultra-high energy cosmic rays by exploiting the geomagnetic deviation of muons in nearly horizontal showers. The distribution of the muons at ground level is well described by a simple parametrization providing a few shape parameters tightly correlated to $X^mu_mathrm{max}$, the depth of maximal muon production, which is a mass indicator tightly correlated to the usual parameter $X_mathrm{max}$, the depth of maximal development of the shower. We show that some constraints can be set on the predictions of hadronic models, especially by combining the geomagnetic distortion with standard measurement of the longitudinal profile. We discuss the precision needed to obtain significant results and we propose a schematic layout of a detector.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
