The simulation calculation and analysis on the electron backscattering for ion barrier films (IBFs) of Al2O3 were performed by Monte Carlo methods. Simulation and experimental detection both found that electron backscattering ratio is inversely proportional to the incident electron energy, proportional to the film thickness and density. But if the film is thick enough, the back scattering ratio will not continue to increase, will maintain a relatively stable value. This work provided a theory support for fabricating high performance low-level-light device.
As an organic photochromic material, spirooxazine attracted widespread attention because of its high fatigue resistance and thermal stability. In this paper, the photochromism of spirooxazine was studied by monitoring the dynamics of holographic gratings in spirooxazine-doped polymer films. A theoretical description for the transformation of spirooxazine and merocyanine molecules was carried out, which agrees well with the experimental results. The photochromism of spirooxazine-doped different matrixes were studied, the photochromic rate and fatigue resistance of spirooxazine-doped SiO2 films were found to be better than spirooxazine-doped PMMA films.
The simulation calculation and analysis on the electron transmittance and ion stopping power for ion barrier films (IBFs)
of BN were performed by Monte Carlo methods. The interaction model between particles and solids were described. We
find the Dead Voltage of BN IBFs is 220V. When the energy of the incident ions is 0.2~0.3KeV, 91%—99% of C+, N+ and O+ are stopped by BN IBFs; while 12%—19% of H+ for BN IBF. The results indicate that BN is an idea candidate for ion barrier films. This work provided a theory support for fabricating high performance low-level-light device.
The simulation calculation and analysis of electron back-scattering characteristics for ion barrier films (IBFs) of Al2O3
was performed by Monte Carlo methods. A physical model for the interaction of low-energy electrons with solid was
described. Trajectory and spatial distribution of the electrons were simulated with MATLAB software.The maximum
ratio of the back-scattered electrons was 19% at the incident energy of 0.24 keV. Beyond this value, the number of backscattered
electron decreased slowly with the increase of the incident energy. The back-scattering ratio increased almost
linearly with the increase of IBF density. When the incident energy was 0.7 keV and the film thickness is higher than 7
nm, the electron back-scattering ratio was always ~17% for the Al2O3 IBF. This work provided a theory support for
fabricating high performance low-level-light device.
Holographic gratings were recorded in spirooxazine doped PMMA films by blue-violet laser (405nm), Nd:YAG laser (532nm) and He-Ne laser (632.8nm), respectively. It was found that the photo-dynamics of the holographic grating was dependent on recording wavelength for the photochromic characteristics of spirooxazines. A theoretical description of orientation and isomerization gratings agrees well with the experimental results. It was also found that a pure isomerization grating is formed by two interferential 405nm beams while a mixed grating consisting of isomerization and orientation components is formed by the visible interferential beams (532nm or 632.8nm). Due to the long life of the isomerization gratings, the holographic interference fringes with different periods were clearly observed by Confocal Laser Scanning Microscope.
Multiple holographic gratings were recorded by 405nm laser in the same location of spirooxazine doped polymer films using peristrophic multiplexing techniques. Diffraction efficiency of each grating was controlled almost uniform by adjusting recording time. It was found that the growth rate of the holographic grating recorded later was lower than that of the earlier one, resulting from the decreased population of spirooxazine molecules. A kinetics description for the overlapped isomerization gratings agrees well with experimental results. Due to the thermal stability of the isomerization grating, multiple interference fringes in the photochromic film were reserved and observed by Confocal Laser Scanning Microscope.
Spirooxazines (SOs) and spiropyrans (SPs) are typical organic compounds exhibiting photochromism. Compared to SPs, SOs show better fatigue resistance and photostability, which provides a possibility of practical applications in lenses of variable optical density, displays, filters and optical-memory devices. The maximum values of photo-induced birefringence of spirooxazine in poly(methyl methacrylate) (PMMA) films pre-irradiated by ultraviolet light was investigated as a function of He-Ne laser (632.8nm) pumping-beam intensity. A dynamics of photo-induced birefringence was recorded by a linearly polarized double-frequency Nd:YAG laser (532 nm) of 0.1 mW as a probe beam. This material exhibited a competing process between photo-orientation and photo-isomerization. The photo-orientation is predominant when the power density of He-Ne beam is lower; while the photo-isomerization is dominant at relatively high power density of He-Ne beam. An improved phenomenological model, elucidating a competition between photo-orientation and photo-isomerization, was precisely presented. Dynamic holographic recording under linear polarized writing beams at 632.8 nm was performed on spirooxazine doped PMMA matrices assisted by UV light. It was found that dynamics of the optical storage signal intensity in the polymer films were dependent on the thermal stability and aggregation of spirooxazine molecules in PMMA matrices. A theoretical description the formation and eraser of the transient orientation grating, competing with isomerization gratings, agrees well with experimental results. The interaction between the chromophores and matrices was also discussed. It was indicated that spirooxazine-doped polymer films are candidates for reversible optical storage medium.
The fabrication of ion barrier film on microchannel plate (MCP) was introduced. The experimental system for
high-temperature vacuum baking on MCP and technological condition were given. The measurement on the electrical
properties, the dead-voltage and other parameters of MCP with an ion barrier film were shown. The changes before and
after high-temperature vacuum baking were also investigated for the MCP with ion barrier film. By analysis and
discussion, it was concluded that high-temperature vacuum baking caused the film's thickness changed, the dead-voltage
decreased, and the electron gain decreased with the increase of the film's thickness for the MCP with an ion barrier film.
Microsphere plate (MSP) is a new type of electron multiplier device. It is similar to the traditional microchannel plate
(MCP) in dimensions and model of operation. Compared with the MCP electron multiplier, the MSP has some unique
characteristics such as a high electron gain, without ion feedback and easy to be fabricated, thus it is widely used in the
fields of imaging and detecting. However, there are some key technologies to fabricate a satisfied MSP. In this paper, the
whole fabrication process of MSP was introduced and some of major processes such as the formation of glass beads, the
sintering of MSP body, and the formation of dynode and electrodes were specially discussed. At the end of the paper, the
optimal processed for the fabrication of MSP was given.
The stopping power of ion barrier films (IBFs) of Microchannel Plate (MCP) in Generation III image tubes for incident
positive ions was described in this paper. Nuclear Stopping Power, Electronic Stopping Power and Mean Range were
introduced. These concepts were analyzed and discussed, combined with Tomas-Fermi shielding potential. The results
of a Monte Carlo simulation on Nuclear Stopping Power, Electronic Stopping Power and Mean Range were also
presented when the ions with different energies were perpendicularly incident to Al2O3 and SiO2 films. The results
indicate that the stopping power of Al2O3 film is stronger than that of SiO2, and the selection of Al2O3 is reasonable and