Spatial distribution function of electrons and thermal neutrons in extensive air showers at sea level

The spatial distributions of electrons and hadrons in extensive air showers, obtained during the PRISMA-32 experiment simulation, are considered. The experiment was simulated for primary protons and iron nuclei using the CORSIKA6.9 and GEANT4.10 software packages. The simulated spatial distribution functions of electrons and neutrons in the extensive air showers (EAS) at the Moscow altitude are compared to the published experimental data of the PRISMA-32 setup.     

Study of EAS Registered by the PRISMA-32 Array and the Cherenkov Water Calorimeter NEVOD

Two installations that allow to detect the EAS hadron component in a continuous mode, the Cherenkov water calorimeter (CWC) NEVOD and PRISMA-32 are operated in MEPhI. The comparison of the characteristics of EAS simultaneously registered by CWC NEVOD and PRISMA-32 are presented. Groups of events with different positions of the shower axis are considered.

     

Primary Cosmic Ray Energy Spectrum Above the ‘‘Knee’’ Measured with PRISMA-32 Array

Physics of Atomic Nuclei - PRISMA-32 (PRImary Spectrum Measurement Array) is working since 2012 in the Scientific & Educational Center NEVOD (NRNU ‘‘MEPhI’’,...     

An electrostatic deflector for a fusion reaction

An electrostatic deflector for separating the fusion evaporation residues from the beam-like products in heavy ion reactions was installed.The evaporation residue separation and identification with the electrostatic deflector setup was tested with the reaction 32S+96Zr at several energies.The fusion evaporation residues and the beam-like particles were well separated after the electrical separation and the experimental fusion cross section obtained from the angular distribution is in good agreement with the calculated value well above the Coulomb barrier.This confirms the reliability of the setup.     

Comment on "Wide-field coherent anti-Stokes Raman scattering microscopy with non-phase-matching illumination"

We comment on a Letter by Toytman et al. [Opt. Lett.32, 1941 (2007)] in which a novel setup for wide-field imaging in coherent anti-Stokes Raman scattering (CARS) microscopy is demonstrated. There the authors state that our phase-matching implementation of a wide-field CARS system [Appl. Phys. Lett.84, 816 (2004); New J. Phys.8, 36 (2006)] suffers from a strong background from the bulk medium. However, our results show quite the contrary, i.e., that our setup provides a very good signal contrast, due to an almost vanishing background level from the bulk solvent.     

Submicrometer digital in-line holographic microscopy at 32 nm with high-order harmonics

Soft-x-ray digital in-line microscopic holography is achieved using a fully coherent high-order harmonic source emitting at 32 nm. Combination of commercial-grade soft-x-ray optics and a back-illuminated CCD detector allows a compact and versatile holographic setup. Different experimental geometries have been tested by imaging calibrated 50 nm tips and 1 microm wires. Spatial resolution of 800 nm is measured with magnifications ranging from 30 to 110 and a numerical aperture around 0.01. Finally, the potentiality of three-dimensional numerical reconstruction from a single hologram acquisition is shown experimentally.     

Laser power noise detection at the quantum-noise limit of 32 A photocurrent

The power noise of a cw Nd:YAG laser system was measured at radio frequencies using the optical ac coupling technique. An additional mode cleaner in the setup allowed a high optical ac coupling amplification of 62.3. For the first time, to our knowledge, a sensitivity of 1.1×10?1? Hz(-1/2) relative power noise was achieved corresponding to an equivalent detected photocurrent of 32 A. High precision optics experiments can utilize this scheme to improve the sensitivity of their photodetectors.     

一种改进激光偏振主动成像的建模及理论分析

提出一种改进激光偏振主动成像的实验方法,给出实验装置原理图,详细分析实验装置的成像原理。在分析目标Mueller矩阵测量方法的基础上,给出改进后激光偏振成像装置偏振度和强度的计算公式,从理论上证明了该方法的可行性。然后针对实验仪器的要求分析了实验装置存在的误差,以及Cassegrain望远镜对目标散射光的消偏现象。该方法与利用双旋转波片技术（DRRT）测量目标散射光的偏振度和强度相比可以降低对实验装置的精度要求,同时可以提高测量速度,不需要进行16次测量,只需1次就可以测量出目标散射光的偏振度和强度,进而得到偏振度和强度图像。     

Generation of arbitrary vector beams based on a single spatial light modulator and a thin-film polarization splitting cubic

A setup for the generation of arbitrary vector beams is proposed. The setup mainly consists of a spatial light modulator(SLM), an angle-adjustable polarization beam splitter modulator, and a spatial filtering imaging system. Compared with the system using a birefringent beam splitter with a non-adjustable splitting angle,the polarization splitting angle of the improved setup can be adjusted by slightly rotating the related mirrors,which will bring more convenience when different wavelengths and different pixel sizes of SLMs are involved.The experimental results also demonstrate that the setup possesses a good polarization-selective imaging ability, which reveals that the setup may also be useful in polarization-selective spatial filtering imaging and polarization-encoded encryption.     

对使用双提升管结构的扩散吸收式制冷系统的性能实验

设计了一台使用双提升管结构且精馏器上多处设置阻流坑的扩散吸收制冷装置,实验研究了氨水充注浓度(24%~36%)、充氢压力(1.5MPa~1.6MPa)、热源加热功率(120W~300W)对制冷系统的影响。结果表明:采用双提升管后,液体循环量增大,循环周期缩短,制冷量增加;适当提高溶液浓度不但可以降低系统发生温度,同时也可以获得较大的冷量,一般为28%~32%为宜;适当降低充氢压力可降低系统发生温度。     

高功率超宽谱脉冲产生实验

 介绍了纳秒传输线充电技术的原理,利用该原理设计了高功率超宽谱脉冲产生实验装置,通过电路模拟计算分析了实验装置的工作过程。结合1.2 MV高压脉冲电源开展了实验,实验中对输出脉冲形状、输出脉冲功率和工作稳定性进行了调试,在2.7 Ω负载上获得输出功率大于30 GW,脉冲宽度1.6 ns,重复频率100 Hz。系统运行稳定,达到设计要求。     

Manifestly non-Gaussian fluctuations in superconductor-normal metal tunnel nanostructures

We propose a mesoscopic setup which exhibits strong and manifestly non-Gaussian fluctuations of energy and temperature when suitably driven out of equilibrium. The setup consists of a normal metal island (N) coupled by tunnel junctions (I) to two superconducting leads (S), forming a SINIS structure, and is biased near the threshold voltage for quasiparticle tunneling, eV≈2Δ. The fluctuations can be measured by monitoring the time-dependent electric current through the system. This makes the setup suitable for the realization of feedback schemes which can be used to stabilize the temperature to the desired value.     

High-accuracy measurement for small scale specular objects based on PMD with illuminated film

In this paper we describe an approach to measure small glossy objects by illuminated film based on Phase Measuring Deflectometry (PMD) system. In this setup, the standard sinusoidal fringe patterns are produced by the photographic film frame (135-film), which is illuminated from behind using LED and diffuser, instead of the well-known LCD monitor plane or digital projector. This setup can avoid the influence of electronic noise and screen refreshing, and fulfill the test of small objects in low cost. Moreover the system is easily calibrated with its vertical setup. With the experiments of measuring a plastic contactless smartcard and a metal plate, it is proven that the setup can reach sub-micrometer accuracy with respect to the data of the Wyko white light interferometer. This setup will be promising in the small scale measurement field.     

Strong CP problem with 10(32) standard model copies

We show that a recently proposed solution to the hierarchy problem simultaneously solves the strong CP problem, without requiring an axion or any further new physics. Consistency of black hole physics implies a nontrivial relation between the number of particle species and particle masses, so that with approximately 10(32) copies of the standard model, the TeV scale is naturally explained. At the same time, as shown here, this setup predicts a typical expected value of the strong-CP parameter in QCD of theta approximately 10(-9). This strongly motivates a more sensitive measurement of the neutron electric dipole moment.     

Frequency stabilization of pulsed CO2 laser using setup-time method

A new method for laser-frequency stabilization by controlling the pulse setup time is presented. The frequency-stabilization system monitors the pulse setup time continuously, and controls it by adjusting the cavity length. Laser frequency is stabilized to the center of the gain curve when the setup time is the shortest. The system is used to stabilize a radio-frequency-excited waveguide CO 2 laser tuned by grating, and the shift of laser frequency is estimated to be less than ±25 MHz for an extended period. The system has the advantages of compact structure, small volume, and low cost. It can be applied for frequency stabilization of other kinds of pulsed lasers with adjustable cavity.     

Simplified setup for high-resolution spectroscopy that uses ultrashort pulses

Using a broadband femtosecond laser and a simple optical setup, we demonstrate narrow-bandwidth-tunable excitation of vibrational modes in CCl4 and CHBr3 liquids. The resolution obtained is 80 times higher than the laser bandwidth. A pair of time-shifted, linearly chirped pulses is created by use of a high-order dispersion-compensated prism-interferometer setup. We use this pulse pair to selectively excite Raman-active transitions. Our setup represents a significant simplification with improved resolution, of previous approaches to the use of ultrashort pulses for chemically selective spectroscopy.     

多路窄脉冲功率线路合成

介绍了传输线变压器的结构特点,对其进行了理论分析和实验研究。采用传输线变压器结构将每路幅度约为4.5 kV/50Ω的4路脉冲合成了幅度约8.8 kV/50Ω的脉冲,通过实验证实了采用多根传输线串并联方式构成的传输线变压器装置可以将多路窄脉冲进行线路功率合成。应用此类结构设计了一种紧凑的高压窄脉冲发生器,将36路8 kV/50Ω的脉冲合成了约46 kV/50Ω的脉冲。采用传输线变压器合成器,应确保各路输入脉冲的前沿抖动足够小和高精度同步。     

Confocal three-dimensional micro-X-ray fluorescence spectroscopy used to retrieve the information covered in printed paper

Confocal three-dimensional micro-X-ray fluorescence (3D-μXRF) spectroscopy based on laboratory X-ray tube was employed to unravel the three-dimensional (3D) distribution of metal element (Fe) inner the paper. According the distribution of the Fe in the paper, the information covered in the printed paper could be retrieved. Before the experiment, the performance of the confocal 3D-μXRF setup was described. The two-dimensional (2D) mapping of printed character covered by the opaque tape and contaminated by the black ink was scanned by confocal 3D-μXRF setup. Furthermore, 2D and 3D mapping of a printed number covered by the paper with printed character was performed by micro-X-ray fluorescence and confocal 3D-μXRF setup, respectively. The scanning results indicated that confocal 3D-μXRF was more suitable for retrieving the information covered in the paper. Furthermore, the confocal 3D-μXRF setup has potential application on the identification of unseen letter or painting that was covered by others, such as ink.     

真空机组循环水控制装置

设计了真空机组的电控装置和循环水冷却装置．电控装置使实验简化，避免了错误地开关冷却水；冷却装置通过水蒸发表面降温实现了循环水的冷却，节约了真空实验用水．     

Space-variant filtering with holographic multifacet elements

We present a spatial filtering method for space-variant operations. The method is based on the combination of a holographic lenslet array and an appropriate filter array. The lenslets produce local Fourier transforms of the object which are filtered in parallel and independently by the spatial filters. The most obvious space-variant setup based on lenslet arrays would consist of many narrow 4f-setups, arranged side by side. The total object would be partitioned into many small object patches, as many as there are lens elements in the lenslet array. However this setup shows the undesired effect of local inversion. Therefore we choose a setup with only one lenslet array and an imaging lens which avoids the local inversion.