We present coherent speckled x-ray diffraction patterns obtained from a monolayer of surface atoms. We measured both the specular anti-Bragg reflection and the off-specular hexagonal reconstruction peak for the Au(001) surface reconstruction. We observed fluctuations of the speckle patterns even when the integrated intensity appears static. By autocorrelating the speckle patterns, we were able ...

Charged-particle beams consisting of protons or helium ions are a type of particulate radiation therapy. They contrast with conventional electromagnetic (i.e., photon) radiation therapy due to several unique properties including minimal scatter as particulate beams pass through tissue, and deposition of ionizing energy at precise depths (i.e., the Bragg peak). Thus, radiation exposure of surrou...

The effect of aberrations in the recording beams of a holographic setup is discussed regarding the deterioration of properties of a reflecting volume Bragg grating. Imperfect recording beams result in a spatially varying grating vector, which causes broadening, asymmetry, and washed out side lobes in the reflection spectrum as well as a corresponding reduction in peak diffraction efficiency. Th...

background: the advantages of proton beam in radiation therapy- like small lateral scattering as well as absence of exit dose tail in the organs which are after the tumor- make it capable of delivering more treatment doses to the target and much lesser to the critical tissues near it. materials and methods: in this study, the monte carlo mcnpx code has been used to simulate a slab head phantom ...

We present experimental measurements of the peak splitting of the reflection spectra of fiber Bragg gratings as a result of birefringence induced by transverse loading of a multicore fiber. Measurements show that the splitting is a function of the applied load and the direction of the load relative to the azimuth of the fiber. A model for calculating the stress in the fiber that is due to an ap...

This Letter presents simulation and experimental results of orientation-dependent transverse stress fiber sensors using fiber Bragg gratings (FBGs) inscribed in four-hole suspended-core fibers. Resonant peak shifts and splitting of FBGs were studied as functions of the applied transverse load and fiber orientation. Both simulation and experimental results revealed that the response of FBGs in s...

We propose a peak detection method for measuring fiber Bragg gratings (FBGs) using convolutional neural network (CNN) to improve the performances of wavelength division multiplexing. In multiplexing, each FBG occupies certain range; therefore, number FBGs that can be installed is limited by band light source. To address this issue, methods overlapping multiple same within single occupied range ...