In this article we perform a general study of possible positron source for linear collider TESLA based on the HERA electron ring. 30 GeV electrons passing 10T wiggler can produce intense synchrotron radiation with characteristic energy of photons of about 6 MeV. High energy photons are converted to few-MeV positrons in a suitable target. The ability of such a source to fit for the TESLA require...

We consider detection of high-energy photons in PET using thick scintillation crystals. Parallax effect and multiple Compton interactions such crystals significantly reduce the accuracy of conventional detection methods. In order to estimate the photon line of flight based on photomultiplier responses, we use asymptotically optimal nonlinear techniques, implemented by feed-forward and radial ba...

Photoluminescence of polycrystalline hexagonal boron nitride (hBN) was measured by means of time-and energy-resolved spectroscopy methods. The observed bands are related to DAP transitions, impurities and structural defects. The excitation of samples by high-energy photons above 5.4 eV enables a phenomenon of photostimulated luminescence (PSL), which is due to distantly trapped CB electrons and...

High-energy X-rays offer several advantages over lower energy photons including: lower skin dose, higher depth dose, smaller scattered dose to tissues outside the target volume and less rounded isodose curves. These advantages in physical dose distributions have led to significant improvements in clinical radiotherapy, and high energy linear accelerators are now a standard fixture of radiothera...

Introduction: Many study shown the effectiveness dose enhancement with gold nanoparticles (GNPs), especially with low-energy x-rays. Recently, proton beam radiation therapy (PBRT) has attention as a treatment for tumors. The advantage in PBRT, which releases high dose at the controllable Bragg peak position that localized for Au target and the released dose increased in depth....

We extend earlier calculations of the attenuation suffered by γ-rays during their propagation from extragalactic sources, obtaining new extinction curves for γ-rays down to 10 GeV in energy, from sources up to a redshift of z = 3. The recognition that high energy γ-rays, propagating over cosmological distances, suffer electron-pair-producing interactions with photons from the extragalactic back...

We have calculated the opacities and secondary production mechanisms of high-energy photons arising in gamma-ray burst internal shocks, using exact cross sections for the relevant processes. We find that for reasonable choices of parameters, photons in the range of tens to hundreds of GeV may be emitted in the prompt phase. Photons above this range are subject to electron-positron pair producti...

We consider the calculation of high energy hadron cascades induced by electron and photon beams in the GeV energy range. The most important source of high energy hadrons is the hadronic interaction of photons from the primary electron-photon shower. The hadronic interaction of high energy photons is described by the vector meson dominance model and by a Monte Carlo version of the dual multistri...