نتایج جستجو برای: ray laser
تعداد نتایج: 478312 فیلتر نتایج به سال:
Background and Aims: According to concerns of technical errors in intraoral radiographs and reports of positive effects of central ray laser pointer on the students, technical errors and shortcomings of earlier research, this study was conducted at Department of Oral and Maxillofacial Radiology of Tehran Azad University to determine the role and use of laser pointer in the technical error mad...
In this paper, a free-electron laser (FEL) growth rate with a laser wiggler in which plasma background is used to generate short wavelengths in x-ray regimes, has been investigated theoretically. A linearly polarized laser pulse, due to having short wiggler periods (inrange) is able to produce coherent radiations in x-ray regions and can be applied as a planar wiggler in a FEL. Phase velocity o...
In this paper, the enhanced continuum x-ray emission from nano-targets irradiated by long laser pulses is investigated numerically. The calculations are performed under different prepulse conditions, and the x-ray emissions from solid and nano-structured target are compared. The results show that x-ray yield can be enhanced significantly using a nano-layer with appropriate density. In addition,...
any change in the refractive index of a laser active medium can lead to serious degradation of beam quality, laser beam modes, laser performance and variation in the intensity distribution. alteration in the refractive index of laser active medium is especially notable in high power lasers. it is clear that in the laser beam production, the pumping agent induces a great amount of heat which...
We present a novel slanted faces of thin-disk composite Yb:YAG YAG laser which is side-pumped by four non-symmetric hollow- ducts. The pump light distribution in the disk is modeled by using Monte-Carlo ray tracing method. The temperature distribution inside the crystal is calculated by taking into account either the concentration of Yb+3 ion or the different transmission of laser output coupl...
We describe a laser-driven x-ray plasma source designed for ultrafast x-ray absorption spectroscopy. The source is comprised of a 1 kHz, 20 W, femtosecond pulsed infrared laser and a water target. We present the x-ray spectra as a function of laser energy and pulse duration. Additionally, we investigate the plasma temperature and photon flux as we vary the laser energy. We obtain a 75 μm FWHM x...
We have successfully demonstrated that the cw x-ray generator can work as a preionization source for a pulsed H F laser. The preionization effect of cw x radiation was revealed by a comparative study of with and without applying x-ray photons to the H F laser. Since dose rate of the cw x-ray generator is easily controllable, the laser output could be measured as a function of initial electron n...
Femtosecond laser-produced plasmas are bright ultrafast line x-ray sources potentially suitable for different applications including material science and biology. The conversion efficiency of the laser energy incident onto a solid target into the x-ray emission is significantly enhanced when a laser prepulse precedes the main pulse. The details of x-ray line emission from solid targets irradiat...
We have developed laser-produced plasma X-ray sources using femtosecond laser pulses at lOHz repetition rate in a table-top size in order to investigate basic mechanism of X-ray emission from laser-matter interactions and its application to a X-ray microscope. In a soft X-ray region over 5 nm wavelength, laser-plasma X-ray emission from a solid target achieved an intense flux of photons of the ...
We have demonstrated repetitive operation of a table-top lambda=13.9 nm Ni-like Ag soft-x-ray laser that generates laser pulses with 10 microJ energy. The soft-x-ray laser is enabled by a Ti:sapphire laser pumped by high-repetition-rate frequency-doubled high-energy Nd:glass slab amplifiers. Soft-x-ray laser operation at 2.5 Hz repetition rate resulted in 20 microwatt average power.
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