Introduction The potential hazards posed by exposure to radiation from radon have been of great concern worldwide, since it is especially associated with increased risk of lung cancer. Some radioisotopes of radon progeny deposited in the human lungs emit β particles followed by the γ rays. While γ rays are comparatively less damaging to the respiratory system than α and β particles, it is the p...

In this work, I present a qualitative discussion on the prospect of production ultra-high photons in blazars. The sources are subclass active galactic nuclei which host supermassive black holes and fire relativistic jets into intergalactic medium. kpc scale believed to be dominated by Poynting flux constitute one most efficient cosmic particle accelerators, that potentially capable accelerating...

From special relativity, photon annihilation process \HepProcess{{\Pgg}{\Pgg}{\to}{\Pep}{\Pem}} prevents cosmic photons with energies above a threshold to propagate long distance in space due their low energy background photons. However, modifications of the dispersion relation from Lorentz invariance violation~(LIV) can cause novel phenomena beyond relativity happen. In this paper, we point ou...

A high energy linear e+e− collider (LC) can also be used as a Photon Collider (PC), using Compton scattering of laser photons on the e+/e− beams. The leading order cross-section for the production of heavy quarks, e+e− → e+e−Q(Q̄)X, at high transverse momenta is calculated for both LC and PC modes. The sensitivity of this process to the parton distribution parametrizations of real photons, espec...

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 a...

For gamma-ray bursts (GRBs) born in a stellar wind, as the reverse shock crosses the ejecta, usually the shocked regions are still precipitated by the prompt MeV γ−ray emission. Because of the tight overlapping of the MeV photon flow with the shocked regions, the optical depth for the GeV photons produced in the shocks is very large. These high energy photons are absorbed by the MeV photon flow...