نتایج جستجو برای: bragg peak
تعداد نتایج: 149178 فیلتر نتایج به سال:
In this paper, we present the generation of high peak-power picosecond optical pulses in the 1.26 μm spectral band from a repetition-rate-tunable quantum-dot external-cavity passively mode-locked laser (QD-ECMLL), amplified by a tapered quantum-dot semiconductor optical amplifier (QD-SOA). The laser emission wavelength was controlled through a chirped volume Bragg grating which was used as an e...
XRD patterns of NIST standard reference materials were collected using a gas proportional detector and a linear Position Sensitive Detector (PSD). Incident beam optics used for data collection consisted of a polycapillary X-ray lens, a graded multilayer parabolic X-ray mirror, and programmable divergence slits. Peak position, width, and intensity were studied with respect to the different exper...
The analysis of double-crystal x-ray rocking curves of single-crystal layered structures can give valuable information on layer strains, displacement of atoms from normal lattice sites (which reduces the structure factor), crystallographic misorientations, and crystal defects. Both strains and misorientations cause shifts in the Bragg angle. These two effects are readily separated using two or ...
The ionization yield of ion tracks in polymers and biomolecular systems reaches a maximum, known as the Bragg peak, close to the end of the ion trajectories. Along the path of the ions through the materials, many electrons are generated, which produce a cascade of further ionizations and, consequently, a shower of secondary electrons. Among these, very low energy secondary electrons can produce...
The normal-incidence efficiencies of two 4800-grooves/mm ruled replica gratings, one with a dual-bandpass molybdenum/silicon multilayer coating and the other with a gold coating, were measured by use of synchrotron radiation in the 125-325-A wavelength region. The peak reflectance of the multilayer coating was 22% in the first Bragg order near 235 A and 28% in the second Bragg order near 126 A....
Pulses of arbitrary temporal shape can be generated by spectrally filtering a short pulse. Frequency selective reflectors, such as fiber Bragg gratings, can be designed to obtain the desired pulse shape. The required distribution of the refractive index modulation, amplitude and phase, can be calculated using inverse scattering techniques. For weak gratings, under the Born approximation, the im...
Conventional radiotherapy with X- and gamma-rays is one of the common and effective treatments of cancer. High energy hadrons, i.e., charged particles like protons and (12)C ions, due to their specific physics and radiobiological advantages are increasingly used. In this study, effectiveness of different radiation types is evaluated on the radio-resistant human HTB140 melanoma cells. The cells ...
For real-time monitoring of the longitudinal position of the Bragg-peak during an ion therapy treatment, a novel non-invasive technique has been recently proposed that exploits the detection of prompt gamma-rays issued from nuclear fragmentation. Two series of experiments have been performed at the GANIL and GSI facilities with 95 and 305 MeV/u (12)C(6+) ion beams stopped in PMMA and water phan...
PURPOSE To determine the relationship between the relative biological effectiveness (RBE) for cell inactivation and linear energy transfer (LET) in the Bragg peak region of (12)C and (20)Ne ions. MATERIALS AND METHODS Chinese hamster ovary (CHO-K1) cells were exposed to high LET (12)C (33.2 MeV, 20.3 MeV, 9.1 MeV at cell entrance) and (20)Ne ions (56.2 MeV, 34.7 MeV, 15 MeV at cell entrance) ...
As proton therapy becomes increasingly popular, so does the need for Monte Carlo simulation studies involving accurate beam line modeling of proton treatment units. In this study, the 24 beam configurations of the Mevion S250 proton therapy system installed recently at our institution were modeled using the TOolkit for PArticle Simulation (TOPAS) code. Pristine Bragg peak, spread out Bragg peak...
نمودار تعداد نتایج جستجو در هر سال
با کلیک روی نمودار نتایج را به سال انتشار فیلتر کنید