Tilt Estimation in Moderate-to-Strong Scintillation

Adaptive optics systems are being applied in ever more challenging environments, for example, the projection of lasers over long horizontal paths through the atmosphere. These long atmospheric paths corrupt the signal received from the beacon and typically yield highly scintillated received wave fronts. Tilt estimation for controlling the fast steering mirror in these systems is complicated by the presence of branch points in the scintillated received wave fronts. In particular, correlation between the tilt and the projected beam's centroid error at the target has been observed in horizontal laser beam projection experiments. The presence of this correlation indicates that better tracking performance should be achievable. We compare the performance of four estimation schemes applied to tilt estimation in a horizontal laser projection system. It is demonstrated that all four schemes underestimate the tilt required to return the laser beam to a target in highly scintillated environments. A method of correcting this tilt is presented, and the expected performance improvement is quantified.     

Pressure-Volume-Temperature Relations in Liquid and Solid Tritium

PVT relations in liquid and solid T₂ near the melting curve were measured over 20.5 K–22.1 K and 0 MPa–7 MPa (0 bar–70 bar) with a cell that used diaphragms for pressure and volume variation and measurement. Because of ortho-para self conversion, the melting pressure P_m and the liquid molar volume V_lm increased with time. The rates were consistent with a second order reaction similar to that for c the J = odd concentration: dc/dt = ?k₁c² + k₂c(1 ? c), where k₁ = 6−9×l0⁻²h⁻¹. By extrapolation, the ortho and para forms differed by ΔP_m~6 bar and ΔV_lm~0.5%. Measurements of the volume change on melting and the thermal expansion and compressibility for liquid T₂ were consistent with those for H₂ and D₂. Impurities such as H₂, HT, DT, and ³He were removed by a technique using an adsorption column of cold activated alumina. Corrections for ³He growth during an experiment were adequate except near the triple point.     

一种旋转式液体颗粒计数装置的研究

介绍了一种旋转式液体颗粒计器装置的原理。该装置将光束以一定转速旋转穿过待测液体 ,由光电探测器接收颗粒产生的散射光能 ,从而确定颗粒大小 ,并根据一定时间内接收的脉冲数确定颗粒数     

液态金属包层中氚提取技术的研究进展

为了完成ITER液态金属包层氚提取系统（TES）的设计,针对液态包层材料——液态锂、液态锂铅、盐溶液和氟化物盐中提取氚的方法进行了调研。调研结果表明：钇粒子床法和溶盐萃取法适用于液态锂中氚的提取;膜渗透法、鼓泡器法和钠回路附设冷阱法对液态锂铅中的氚提取是很有希望的,尽管氚扩散通过锂铅合金边界层的速率缓慢,增大了氚提取的技术难度,但鼓泡器法具有更高的气一液间接触面积,自90年代以来技术发展最为成熟;氦气清洗和真空萃取法已成功运用于氟化物盐包层中氚的提取。尽管任何一种氚提取方法都有工程化的现实前景,但为解决氚提取系统中杂质影响和各种相互作用的问题,开展材料和基础化学方面的广泛研究是必要的。     

Determining the Specific Activity of Tritium in Samples of Spent Nuclear Fuel

Radiochemistry - Procedure for determining the specific activity of tritium in samples of spent nuclear fuel (SNF) was developed and methodologically certified. The procedure was used to determine...     

Optimization of Conditions for Tritium Labeling of Organic Compounds by Isotope Exchange with Tritium Water,Based on the Concepts of Reactions on the Catalyst Surface

To reveal factors affecting the tritium labeling by isotope exchange with tritium water and to elucidate the reaction mechanism, the concepts of processes involved in heterogeneous catalysis were considered. Conditions were optimized for tritium labeling of deltamethrin, pargiline, trichostatin, ciprofloxacin, and 1,3-O-dibenzylglycerol. Samples with the molar radioactivity of 9.3, 0.5, 1.8, 35.1, and 57.3 Ci mmol⁻¹, respectively, were prepared.__________Translated from Radiokhimiya, Vol. 47, No. 4, 2005, pp. 368–373.Original Russian Text Copyright © 2005 by Shevchenko, Nagaev, Myasoedov.     

液闪TDCR活度测量装置的研制

建立了基于效率计算的液闪三双符合比活度测量装置,通过设定甄别阈、扩展死时间、符合技术手段消除了光电倍增管的热噪声和余后脉冲的影响。该装置测量氚水、¹⁴C和⁹⁹Tc的双管符合探测效率达到54%、96.2%和97.2%。用NIST氚水标准物质对新建立的实验装置进行验证,E_n数检验结果满意。     

Liquid Helium and Liquid Neon-Sensitive, Low Background Scintillation Media for the Detection of Low Energy Neutrinos

The use of liquid helium and neon as scintillators for neutrino detection is investigated. Several unique properties of these cryogens make them promising candidates for real-time solar neutrino spectroscopy: large ultraviolet scintillation yields from ionizing radiation, transparency to their own scintillation light, and low levels of radioactive impurities. When neutrinos scatter from electrons in liquid helium or neon, ultraviolet light is emitted. The ultraviolet scintillation light can be efficiently converted to the visible with wavelength shifting films. In this way the neutrino-electron scattering events can be detected by photomultiplier tubes at room temperature. We conclude that the solar neutrino flux from the p+pe⁺+d+ _e reaction could be characterized and monitored versus time using a 10 ton mass of liquid helium or neon as a scintillation target.     

Thermal Radiation Calorimeter for Measuring the Specific Heat Capacity of Liquid Samples

A new thermal radiation calorimeter for measuring the specific heat capacity of liquid samples continuously in the temperature range from 280 to 360 K is described. The heat input to the sample cell from the heater by thermal radiation is estimated using the effective emissivity, which is the apparatus constant. The heat capacity of a sample can be calculated from the temperatures of the sample and the heater, and the temperature change rate of the sample. The present sample cell was made of Pyrex glass; therefore most liquid samples do not react with the sample cell, and blackening of the surface of the sample cell is not necessary in the present temperature range. The specific heat capacities for ethanol, ethylene glycol, n-heptane, n-valeric acid, and water+ethanol mixtures were measured to confirm the reliability of the present calorimeter.     

检测实验室日常检测工作中应注意的几个问题

文章对检测实验室日常检测工作中应注意的几个问题进行了总结，并阐明了这些问题应加以高度重视，强调了重视它们对于检测能力和水平的稳健提高具有很大现实意义。     

纯净水电导率测量结果的不确定度评定

对纯净水电导率测量不确定度进行合理评定,估计分析不确定度的来源,综合分析得出其扩展不确定度.     

An Optimization Criterion for Linear Inverse Estimation

Integrated mean square error is proposed as an optimizing criterion for the linear inverse estimation problem. Results are compared with the classical and inverse procedures. A generalization allowing for several predictor variables is considered.

Under certain conditions both the classical and the inverse methods may tend towards the optimal estimator. Also, the sample inverse estimator is shown to be optimal for a realistic situation     

卡尔•费休库仑法测量气体水分的研究

卡尔·费休库仑法是一种测定水分含量的经典方法,具有较高灵敏度和准确度,在气体水分含量测定领域具有一定的应用潜力。本文采用比较法研究卡尔·费休库仑法测量气体水分的准确度,即将湿度发生器产生的稳定湿气分别提供给经校准过的精密露点仪和卡尔·费休库仑法水分仪进行测定。研究起始漂移值和进样量等因素对测量结果重复性的影响,结果表明降低起始漂移值和增大进样量能提高测量结果的重复性;研究卡尔·费休试剂中甲醇含量对反应的影响,结果表明甲醇含量越低,示值误差越大;研究露点在-60~-16℃范围内卡尔·费休法的准确度,结果表明,在水分含量较高的范围(露点:-50.5~-19.9℃)内,卡尔·费休法露点示值误差较小0.4~2.6℃;在水分含量较低(露点:-58.1℃)时,卡尔·费休法露点示值误差为-5.9℃。上述研究结果对卡尔·费休库仑法用于气体水分含量的测定具有一定参考意义。     

液相微萃取-HPLC法测定复杂样品中的双酚A

目的研究不同包装的牛奶、矿泉水以及购物小票等复杂样品中双酚A(BPA)的富集和测定。方法采用两相中空纤维(HF)液相微萃取(LPME)技术结合高效液相色谱(HPLC)法测定BPA,优化萃取剂、样品溶液p H值、萃取温度、萃取时间、搅拌速率以及Na Cl浓度等LPME参数,获得BPA的富集倍数和线性方程。结果确定了最优化的LPME条件,以正辛醇为萃取剂,样品溶液p H值为6.2,萃取温度为40℃,萃取时间为40 min,搅拌速率为500 r/min,不加盐调节;线性方程为y=590.03x+39.98,相关系数r=0.9997,检测限为12.7μg/L,相对标准偏差(RSD)为4.2%,且BPA的富集倍数可达205倍,平均回收率达90.0%~105.0%。结论该方法大大提高了检测的灵敏度和选择性,用于实际样品分析时,结果稳定、可靠。     

Standardization of 68Ge/68Ga Using Three Liquid Scintillation Counting Based Methods

A solution containing ⁶⁸Ge in equilibrium with its daughter, ⁶⁸Ga, has been standardized for the first time at the National Institute of Standards and Technology (NIST) using 3 liquid scintillation-based techniques: live-timed 4πβ -γ anticoincidence (LTAC) counting, the Triple-to-Double Coincidence Ratio (TDCR) method, and ³H-standard efficiency tracing with the CIEMAT¹/NIST (CNET) method. The LTAC technique is much less dependent on level scheme data and model-dependent parameters and was thus able to provide a reference activity concentration value for the master solution with a combined standard uncertainty of about 0.3 %. The other two methods gave activity concentration values with respective differences from the reference value of +1.2 % and −1.5 %, which were still within the experimental uncertainties. Measurements made on the NIST “4π”γ secondary standard ionization chamber allowed for the determination of calibration factors for that instrument, allowing future calibrations to be made for ⁶⁸Ge/⁶⁸Ga without the need for a primary measurement. The ability to produce standardized solutions of ⁶⁸Ge presents opportunities for the development of a number of NIST-traceable calibration sources with very low (<1 %) relative standard uncertainties that can be used in diagnostic medical imaging.