透0.45 μm～1.6 μm反8 μm～12 μm宽光谱分色滤光片的制备

光谱分色滤光片对成像光谱技术至关重要,是实现光电仪器体积小、质量轻的一个重要器件.根据金属膜具有高反射率的特点和可以进行诱增透的原理,介绍了透0.45 μm～1.6 μm反8 μm～12 μm光谱分色滤光片的膜料选择和膜系设计,并应用JGP560A2型磁控溅射镀膜机制备出了光谱性能和理化性能较好的宽光谱分色滤光片,其光谱性能达到0.45 μm～1.6 μm波段范围内,平均透过率大于80%;8 μm～12 μm波段范围内,平均反射率大于91%.     

Producing μ−d and μ−t in vacuum

After the feasibility of vacuum isolated ^–d production was demonstrated at TRIUMF in 1989, development was begun on a target system that would take advantage of the process to aid in the understanding of the muon catalyzed fusion cycle. Minimal neutron backgrounds, the ability to use silicon detectors, and compatibility with tritium were considered important for a very versatile target system. The advantages which the target gives in isolating CF process will be outlined.     

Zero-field μSR and low-temperature μ+ diffusivity in copper

In this paper I review the history of ⁺ diffusion studies in copper, with particular emphasis on the increased low-temperature diffusivity which has been known for several years now. I survey the theory and practice of the zero-fieldSR method, which has come into increasing favor in the study of muon diffusion and trapping in metals, and discuss its application to the low-temperature copper problem.     

Search for lepton number violating decays B+ → π- μ+ μ+ and B+ → K- μ+ μ+

A search is performed for the lepton number violating decay B+ → h- μ+ μ+, where h- represents a K- or a π-, using an integrated luminosity of 36 pb(-1) of data collected with the LHCb detector. The decay is forbidden in the standard model but allowed in models with a Majorana neutrino. No signal is observed in either channel and limits of B(B+ → K- μ+ μ+) < 5.4×10(-8) and B(B+ → π- μ+ μ+) < 5.8×10(-8) are set at the 95% confidence level. These improve the previous best limits by factors of 40 and 30, respectively.     

Fullerenes with μSR

The current status ofSR results on muonium states in the pure fullerenes C₆₀ and C₇₀ is summarized. The hyperfine interaction between the unpaired electron and the muon provides unique information on the molecular dynamics and local electronic structure of the fullerenes. Recent results on the alkali doped C₆₀ series are also presented.     

Search for B(s)(0) → μ+ μ- and B(0) → μ+ μ- decays with CDF II

A search has been performed for B(s)(0) → μ+ μ- and B(0) → μ+ μ- decays using 7 fb(-1) of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron collider. The observed number of B(0) candidates is consistent with background-only expectations and yields an upper limit on the branching fraction of B(B(0) → μ+ μ-) < 6.0 × 10(-9) at 95% confidence level. We observe an excess of B(s)(0) candidates. The probability that the background processes alone could produce such an excess or larger is 0.27%. The probability that the combination of background and the expected standard model rate of B(s)(0) → μ+ μ- could produce such an excess or larger is 1.9%. These data are used to determine B(B(s)(0)→ μ+ μ-) = (1.8(-0.9) (+1.1)) × 10(-8) and provide an upper limit of B(B(s)(0) → μ+ μ-) < 4.0 × 10(-8) at 95% confidence level.     

A microwave μSR spectrometer

A microwave-SR (WSR) spectrometer has been developed which operates in the frequency region of 1–2 GHz. The spectrometer geometry is that of longitudinal field (LF)SR and is typically used in time integral measurements. The high frequency of this instrument distinguishes it from the currently used RFSR spectrometers and allows high field measurements to be made for normal Mu type systems. This allows one to avoid low field broadening mechanisms that may be present, either from electronic spin-lattice relaxation or nuclear hyperfine interactions.Technical details of the tunable microwave cavity and the RF coupling scheme are presented. Experimental spectra of Mu lines in SiO₂ and GaAs are displayed.     

Neutron scattering and μSR

The paper discusses the characteristics of neutron scattering andSR in order to find the collaborating works with both techniques. The discussions are made on four subjects, random spin systems, itinerant electron magnetism, surface and real time spectroscopy, with some detailed discussions on the cluster spin glass 88FeTiO₃-12Fe₂O₃ and itinerant ferromagnet MnSi, for which the collaboration has yielded the fruitful results.Finally I would like to thank T. Yamazaki, K. Nagamine and Y.J. Uemura for crucial discussions on the SR and Y. Endoh for discussions on the neutron scattering.     

High pressure μSR studies

The high pressureSR spectrometer [1] formerly located at CERN has been transferred to theE1-beamline at PSI and put back into operation with only minor modifications. The essential features of the high pressure apparatus are described below. The instrument covers a pressure range up to 0.7 GPa which can be extended to 1.4 GPa depending on the design of the high pressure cell. First measurements at PSI were successfully carried out with a single crystalline sample of Gd metal. New developments in high pressure cell design are presented. They are expected to further improve the signal/background ratio and to extend the pressure range to 1 GPa. One type of cell will allow temperatures above 380 K.This work was supported by the German Federal Minister for Research and Technology (Bundesminister für Forschung und Technologie [BMFT]) under Contract Nr. 03KA2-TUM-4 and 03SE3STU.     

On fluctuations in μ-space

A master equation is derived microscopically to describe the fluctuating motion of the particle density in . space. This equation accounts for the drift motion of particles and is valid for any inhomogeneous gas. The Boltzmann equation is obtained from the first moment of this equation by neglecting the second cumulant (the pair correlation function). The successive moments form coarse-grained BBGKY-like hierarchy equations, in which small spatial regions with r_ij < the force range are smeared out. These hierarchy equations are convenient for investigating the nonequilibrium long-range pair correlation function, which arises mainly from sequences of isolated binary collisions and gives rise to the much-discussed long-time tail and the logarithmic term in the density expansion of transport coefficients. It is shown to have a spatial long tail, like the Coulombic potential, in a steady laminar flow. The stochastic nature of the nonlinear Boltzmann-Langevin equation is also investigated; the random source term is found to be expressed as a linear superposition of Poisson random variables and to become Gaussian in special cases.     

High efficiency cw far infrared lasers at 119 μm and 127 μm

The optically pumped FIR laser lines at 119 m from CH₃OH and at 127 m from¹³CD₃OH are known to be the most powerful in the far infrared spectral region. We report on efficiency measurements for our waveguide laser system. The effect of various parameters was investigated, resulting in the highest efficiency ever reported for the 119 m line. The Stark effect and others parameters of the 127 m were measured, and a new¹³CD₃OH laser line at 175 m discovered, with the same pump transition. These measurements are helpful for completing the assignment already proposed for the 127 m line.     

A comparative study of laser tissue interaction at 2.94 μm and 10.6 μm

Laser cutting of gelatin and tissue with Er and CO₂ lasers is explained by combined action of evaporation, ejection of liquid and elastic deformation of the region of radiation impact. It is shown that the ejection mechanism is more pronounced at 2.94 m than at 10.6 m. The use of high speed photography has revealed the influence of the temporal pulse shape. The experimental results are explained by a thermo-mechanical model.     

1.56 μm and 2.86 μm Raman lasers based on gas-filled anti-resonance hollow-core fiber

We report here a single-pass 1.56 μm fiber gas Raman laser in a deuterium-filled hollow-core fiber and a 2.86 μm cascade fiber gas Raman laser with methane in the second stage. The maximum output powers at 1.56 and 2.86 μm are 27 and 8.5 m W with Raman conversion efficiency of 30% and 42%, respectively. The results offer a new method to produce a 1.5 μm fiber source and prove the potential of the cascade fiber gas Raman laser in extending the available wavelength.     

The μSR facilities at PSI

TheSR Facility Instruments presently available at PSI and the envisaged medium- and long-term developments are presented. The plans focus on further upgrades of the existing instruments and the development of new techniques using the very high fluxes becoming available at PSI, in particular the setup of a beamline with a fast kicker for muons on request (MORE) and the development of very low energy muon beams.     

A μs-isomer in135Te

The deexcitation of an isomer with a half-life of 0.51±0.02 μs in ₅₂ ¹³⁵ Te₈₃ has been studied. A first level scheme of this nucleus with two protons and one neutron beyond the doubly magic¹³²Sn has been established. The most probable interpretation of the experimental data is that the 83rd neutron is coupled to the known two-proton levels of¹³⁴Te.     

Search for B(s)(0) → μ+ μ- and B(0) → μ+ μ- decays in pp collisions at sqrt[s] = 7 TeV

A search for the rare decays B(s)(0) → μ+ μ- and B(0) → μ+ μ- is performed in pp collisions at sqrt[s] = 7 TeV, with a data sample corresponding to an integrated luminosity of 1.14 fb(-1), collected by the CMS experiment at the LHC. In both cases, the number of events observed after all selection requirements is consistent with expectations from background and standard-model signal predictions. The resulting upper limits on the branching fractions are B(B(s)(0) → μ+ μ-) < 1.9 × 10(-8) and B(B(0) → μ+ μ-)<4.6 × 10(-9), at 95% confidence level.     

应用于水下能分辨粒径10 μm～500 μm尾流气泡的成像系统

针对尾流气泡成像存在的难点,采用片光源切片扫描与高速摄影相结合的技术手段,研制了一套水下激光成像系统。该系统采用激光片光照明,避免了尾流区气泡图像层叠;设计了3组倍率可切换镜头,实现了对大动态范围（10 m～500 m）粒径小气泡的成像;将镜头分成前后组,以平行光中继,通过片光与前镜组的同步移动,可实现尾流区一定体积内气泡图像的采样,同时还能保证扫描过程中始终成像清晰。此系统通过在海域进行试验,放置深度为5 m,气泡由目标船产生,产生气泡粒径范围10 m～2 000 m,结果表明,系统成像效果良好,满足项目技术要求。     

High peak power 1.0 μm and tri-wavelength 1.3 μm Nd:ScYSiO_5 crystal lasers

With a Nd:ScYSiO_5 crystal, a high peak power electro-optically Q-switched 1.0 μm laser and tri-wavelength laser operations at the 1.3 μm band are both investigated. With a rubidium titanyle phosphate(RTP) electro-optical switcher and a polarization beam splitter, a high signal-to-noise ratio 1.0 μm laser is obtained, generating a shortest pulse width of 30 ns, a highest pulse energy of 0.765 mJ, and a maximum peak power of 25.5 kW,respectively. The laser mode at the highest laser energy level is the TEM200 mode with the Mvalue in the X and Y directions to be M_x~2= 1.52 and M_y~2= 1.54. A tri-wavelength Nd:ScYSiO_5 crystal laser at 1.3 μm is also investigated. A maximum tri-wavelength output power is 1.03 W under the absorbed pump power of7 W, corresponding to a slope efficiency of 14.8%. The properties of the output wavelength are fully studied under different absorbed pump power.     

Decay rate of a bound μ-meson

The decay rate of the bound -meson is calculated in the frame-work of the theory of weak interactions with spin-zero intermediary boson. It is shown that it decreases monotously with the atomic number of the -mesoatom, as required by the experiment.The thesis, of which this paper is a part, was worked out under the consistent guidance of Prof. V. Votruba, Dr. Sc., which is gratefully acknowledged.