Introduction: Proton radiotherapy is the one of advanced teletherapy methods. The protons deposit their maximum energy in a position called Bragg peak. Therefore, for treatment of cancer, the tumor should be placed at the Bragg peak or SOBP. The scattered photons and neutrons is a challenge in proton radiotherapy. The aim of this study is calculation of absorbed dose from scatt...

We characterize and compare four different types of focusing optics for hard X-rays, suitable for femtosecond X-ray diffraction experiments, using a tabletop femtosecond laser-based plasma source. We demonstrate a 23μm focus with a toroidally bent Ge single crystal. A maximum flux of 7 × 108 photons/(s mm2) is generated in a 32μm focus using a multi-layer mirror. An elliptical glass capillary y...

It has been speculated earlier that Gamma Ray Bursts are sources of ultrahigh energy cosmic rays. Recently, the search for high energy photons from Gamma Ray Bursts by Milagro group has put limits on the isotropic luminosity of these transient sources in very high energy photons. The implications of the results obtained by Milagro to our understanding of the ultrahigh energy cosmic ray spectrum...

The aim of this analysis is to search for direct photons, i.e. photons that are not produced in hadron decays such as π → γγ or η → γγ. Direct photons are generally subdivided into prompt photons from initial hard parton scatterings and thermal photons from a possible quark-gluon plasma and from the hadron gas. Prompt photons are produced before a possible quark-gluon plasma has formed. Above a...

In the algorithm of Leksell GAMMAPLAN (the treatment planning software of Leksell Gamma Knife), scattered photons from the collimator system are presumed to have negligible effects on the Gamma Knife dosimetry. In this study, we used the EGS4 Monte Carlo (MC) technique to study the scattered photons coming out of the single beam channel of Leksell Gamma Knife. The PRESTA (Parameter Reduced Elec...

In new physics searches involving photons at the LHC, one challenge is to distinguish scenarios with isolated photons from models leading to "photon jets". For instance, in the context of the 750 GeV diphoton excess, it was pointed out that a true diphoton resonance [Formula: see text] can be mimicked by a process of the form [Formula: see text], where S is a new scalar with a mass of 750 GeV a...

We present a method for interactive global illumination computation which is embedded in the framework of Quasi-Monte Carlo photon tracing and density estimation techniques. The method exploits temporal coherence of illumination by tracing photons selectively to the scene regions that require illumination update. Such regions are identified with a high probability by a small number of the pilot...

As currently implemented, single-photon sources cannot be made to produce single photons with high probability, while simultaneously suppressing the probability of yielding two or more photons. Because of this, single photon sources cannot really produce single photons on demand. We describe a multiplexed system that allows the probabilities of producing one and more photons to be adjusted inde...

We examine the effect of Lyman continuum photons on the 21 cm background in the highredshift universe. The brightness temperature of this transition is determined by the spin temperature Ts, which describes the relative populations of the singlet and triplet hyperfine states. Once the first luminous sources appear, Ts is set by the Wouthuysen-Field effect, in which Lyman-series photons mix the ...

The ability to produce single photons and entangled photon pairs in desired quantum states is essential in any system intended to handle quantum information. Single photons serve as qubits in quantum computers, and the most powerful operations in those computers are performed by entangling them. Further, entangled pairs of photons are the carriers for signals in quantum-encrypted communications...