Differentiation between tracks and damages in SSNTD under the atomic force microscope

We have observed three-dimensional sponge-like structures as well as strips of connecting pits on the surface of the LR 115 detector after etching, which can be confused with the small tracks formed after short etching time. We have employed an atomic force microscope (AFM) to study these “damages” as well as genuine alpha tracks for short etching time. It was found that while the track and damage openings could be similar in size and shape, the depths for the damages were consistently smaller. Therefore, the depth of the pits will serve as a clear criterion to differentiate between tracks and other damages. The ability to discriminate between genuine tracks from other damages is most important for etching for short time intervals.     

相似路径台风风暴潮过程对比

基于MIKE 21模型和Holland台风风场模型,构建了1909号利奇马和0509号麦莎2次相似路径台风期间的风场和气压场,并模拟了相应的风暴潮过程。结果表明：台风中心附近增水变化显著,浙江东北部海域在台风登陆期间的增水更大;受台风强度影响,台风利奇马期间增水高值区更大,部分海域2次台风期间最大增水差值接近1.0 m;潮致欧拉余流速度较大值主要分布在100 m水深以浅的海域,量值超过20 cm/s,江苏沿海、台湾东北部海域存在欧拉余环流;台风利奇马期间近海斯托克斯余流值普遍小于麦莎期间;斯托克斯余流项对台风期间长江口、浙闽等近海浅水区短期物质输运过程起一定主导作用。用EMD方法和Hillbert变换分析了典型站点风暴潮位的特征,发现站点IMF1模态和天文潮位较吻合;水深和IMF3模态的最大功率谱密度呈现出较高的相关性,并且随着水深的增加,IMF3模态的最大功率谱密度逐步变大。     

Designing polymers for nuclear track detection

This article describes our attempts since 1996 to systematically design and synthesize monomers and corresponding polymers for nuclear track detection. So far more than 15 homopolymers/copolymers have been prepared and tested by us for this purpose. Some of these polymers show better track detection characteristics vis-á-vis commercially available poly allyl diglycol carbonate (PADC) track detectors.      

Comparison of responses of LR-115A, CR-39 and PM-355 track detectors to pulsed low-energy proton streams

The paper concerns applications of LR-115A, CR-39 and PM-355 solid-state nuclear-track detectors (SSNTDs) for investigation of pulsed fluxes of protons below 300 keV. The proton streams were generated by the RPI-IBIS device operated with hydrogen puffing [Baranowski et al. 2000. Studies of hydrogen discharges in RPI-type devices with different electrode configurations. Czech. J. Phys. 50 (Suppl. S3), 101–107]. To perform ion mass- and energy-analysis, a Thomson mass-spectrometer equipped with a special input system and exchangeable detectors was used. A quantitative analysis of proton tracks upon Thomson parabolas was performed by means of an optical microscope equipped with a CCD camera. It made possible to measure proton tracks and to determine their statistics. The paper presents proton energy spectra recorded with the selected detectors, and responses of these detectors to protons of energy from about 30 to 300 keV. The results are important for verification of detector characteristics and for measurements of protons at different experimental conditions.     

Topological laminations on surfaces

We present and prove a topological characterization of geodesic laminations on hyperbolic surfaces of finite type.     

Optimization of the heavy nuclei track etching in olivine crystals from meteorites

The investigation of the track etching velocity dependence for nuclei with Z50 on pH of the etching solution in the olivine crystals from Marjalahti and Eagle Station meteorites, containing galactic cosmic-ray nuclear tracks and also the crystals from Marjalahti meteorite, calibrated at the UNILAC (GSI, Darmstadt) with 14.17 MeV/N ²⁰⁸Pb nuclei, were performed.

The pH of the etching solution were changed from 7.8 to 9.4. It is shown that the optimal track etch condition were realised at pH of etching solution in the interval from 8.4 to 8.8.

The results of the Galactic cosmic-ray nuclei tracks with Z83 revealed in olivine crystals are presented. They were additionally irradiated at 90% to the surface with accelerated 14 MeV/N ¹³²Xe nuclei.     

Determination of microquantities of Be in samples using α-sensitive track etch detectors

A new technique of determining Be content in samples using 4.66 MeV γ-rays is proposed. This energy range is sufficient to knock out the neutron from the ⁹Be nucleaus and to excite the first 2.9 MeV level of the ⁸Be nuclei. 1.5 MeV alpha particles are registered by means of CR-39 or cellulose nitrate detectors. Alpha particles produced in the reaction of γ-rays with Li nuclei which are contained in samples may cause the background. The latter is excluded by heating of samples before irradiation for Li molecules to be evaporated. ¹¹B nuclei do not produce alpha particles at the energy range of γ-rays presented above.The results obtained in the experiments of determining Be content in natural beryl crystal samples are in good agreement with their known chemical composition. Microparticles containing Beryllium were found in soil samples from the Ust-Kamenogorsk are deposit region, which contains 10⁻³ − 10⁻⁴ g/g of Be. The sensitivity of the method is 10⁻⁶ g/g of Be in solids.