نتایج جستجو برای: electron beam pumping
تعداد نتایج: 413740 فیلتر نتایج به سال:
We describe an advanced and highly sensitive instrument for quantum state-resolved molecule-surface energy transfer studies under ultrahigh vacuum (UHV) conditions. The apparatus includes a beam source chamber, two differential pumping chambers, and a UHV chamber for surface preparation, surface characterization, and molecular beam scattering. Pulsed and collimated supersonic molecular beams ar...
In an electron curtain accelerator, when the electron beam passes through the titanium exit window of the accelerator chamber, X-ray photons are produced as a negative by-product of retarding accelerated electrons. Controlling the produced X-ray photons to avoid their detrimental effects or in fact, proper shielding of the accelerator is an important issue that has to be considered in the use o...
It is very interesting that the enhanced peaks near 1150 and 1550 nm are observed in the photoluminescence (PL) spectra in the quantum system of Si-Ge nanolayer structure, which have the emission characteristics of a three-level system with quantum dots (QDs) pumping and emission of quasi-direct-gap band, in our experiment. In the preparing process of Si-Ge nanolayer structure by using a pulsed...
Spin-polarized ion scattering spectroscopy using an electron-spin-polarized 4He+ ion beam was developed as a novel analytical method of the element selective spin state at outermost surfaces. Spin-polarized He+ ions were generated from the Penning ionization of metastable He 2(3)S1 atoms (He*), which were spin-polarized by optical pumping (OP). The spin polarization of He* (PHe*) was observed t...
We describe a simple design, laser-diode-pumped cw Nd:YAG active-mirror laser and present a thermal analysis of the crystal. A cw output power of 2.4 W and an M(2) beam quality value of less than 1.9 at an incident pumping power of 8.9 W were obtained. From the thermal analysis we predict that the output power can be increased by increasing the pump beam diameter and the pump power at a constan...
This experiment is an example of magnetic resonance a class of experiments in which very small energy separations (typically 10−7 eV) of quantum mechanical states are determined by measuring the frequency of a sinusoidally varying magnetic field, which induces transitions between the states. Some examples of magnetic resonance experiments are: nuclear magnetic resonance [1, 8], nuclear quadrupo...
The generation of coherent Terahertz (THz) radiation is studied which is produced from moving the relativistic electron beam through a helical wiggler with axial magnetic field. The relativistic electron beam is modulated via interacts with the beat wave of two laser beams that have frequency difference in THz range. When the modulated relativistic beam of electrons go through the helical wiggl...
Background: The herb feverfew (Tanacetum parthenium L., Asteraceae) has an ancient reputation as an effective anti-inflammatory, analgesic, antipyretic, and anti-asthmatic agent. Parthenolide a gemacranolide-type sesquiterpene lactone is the major constituent of European feverfew. Materials and Methods: The present study was intended to evaluate the in vivo antioxidant potential and radioprotec...
background: gold nanoparticles are emerging as promising agents for cancer therapy and are being investigated as drug carriers, photothermal agents, contrast agents and radiosensitisers. objective: the aim of this study is to understand characteristics of secondary electrons generated from interaction of gold nanoparticles gnps with x-rays as a function of nanoparticle size and beam energy and ...
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