NIST Calibration of a Neutron Spectrometer ROSPEC

A neutron spectrometer was acquired for use in the measurement of National Institute of Standards and Technology neutron fields. The spectrometer included options for the measurement of low and high energy neutrons, for a total measurement range from 0.01 eV up to 17 MeV. The spectrometer was evaluated in calibration fields and was used to determine the neutron spectrum of an Americium-Beryllium neutron source. The calibration fields used included bare and moderated ²⁵²Cf, monoenergetic neutron fields of 2.5 MeV and 14 MeV, and a thermal-neutron beam. Using the calibration values determined in this exercise, the spectrometer gives a good approximation of the neutron spectrum, and excellent values for neutron fluence, for all NIST calibration fields. The spectrometer also measured an Americium-Beryllium neutron field in a NIST exposure facility and determined the field quite well. The spectrometer measured scattering effects in neutron spectra which previously could be determined only by calculation or integral measurements.     

PIN结构自扫描光电二极管列阵的研究

通过对再充电采样方式的自扫描光电二极管列阵（ＳＳＰＡ）工作原理分析，对列阵中光电二极管工作模式进行较深入的探讨，指出影响其性能的主要因素。提出了用ＰＩＮ结构代替常用的ＰＮ结结构的光电二极管组成ＳＳＰＡ。经过ＰＩＮ结构和ＭＯＳ电路兼容工艺方案的分析及实验，测试结果表明ＰＩＮ结构有利于改进ＳＳＰＡ的性能，是研究高性能ＳＳＰＡ的新结构。     

大气垂直探测仪光谱定标

为了大气垂直探测仪能够进行精确的光谱测量,对其进行光谱定标.大气垂直探测仪使用面阵探测器,由于离轴像元接收的光线不平行于光轴,使仪器函数发生变化.本文针对大气垂直探测仪使用的16x4元面阵探测器理论分析给出仪器函数,讨论其对光谱定标的影响,并将利用理论分析结果及利用气体吸法测得的光谱,对大气垂直探测仪进行了光谱标定,光谱定标精度达10-5.采用面阵探测器的干涉仪,边缘视场像元所测光谱会向低频漂移,因此必需研究干涉仪的仪器函数,从而消除光谱漂移对边缘视场光谱定标的影响.     

光栅型光谱仪波长准确度校准方法

针对低压汞灯谱线能量弱且量值无法溯源的难题,本文以1 064 nm单块固体环形激光器作为基频光,经过两次倍频分别得到532 nm、266 nm激光,通过调制转移光谱技术将532 nm激光频率锁定在碘分子超精细谱线上,以此为基础对光栅型光谱仪的波长准确度进行校准。实验结果表明,稳频波长源输出的三波长具有严格的倍数关系,能够准确有效地对光栅型光谱仪波长准确度进行校准,具有很好的实际应用价值。     

分压强质谱计校准装置的研制

分压强质谱计校准装置用于质谱计的校准。本文介绍了分压强质谱计校准装置的结构、工作原理及分压强测量方法,并给出了分压强测量的不确定度分析。     

利用QED—200硅光电二极管自校准技术建立微光功率标准

着重介绍利用硅光二极管自校准技术建立激光功率标准的基本原理、实验装置的组成和实验结果。     

硅光电二极管探测器在低能X射线辐射场上的标定

在同步辐射X射线能量标定前,需要对作为传递探测器的硅光电二极管进行标定.利用低能X射线10～50 kV空气比释动能基准装置,研究硅光电二极管的辐射响应并用它测量辐射场的均匀野大小.将硅光电二级管AXUV-100G置于低能X射线基准辐射场中,测得AXUV-100G作为传递探测器在10～40 keV能量范围的能量响应较高,...     

The Combined Use of a Gas-Controlled Heat Pipe and a Copper Point to Improve the Calibration of Thermocouples up to 1100 ˚C

The calibration of platinum-based thermocouples from 420 °C to 1,100 ˚C is currently carried out at INRIM making use of two different apparatus: for temperatures below 930 ˚C, a potassium gas-controlled heat pipe (GCHP) is used, whereas a metal-block furnace is adopted for higher temperatures. The standard uncertainty of the reference temperature obtained in the lower temperature range is almost one order of magnitude better than in the higher temperature range. A sealed copper cell was investigated to see if it could be used to calibrate thermocouples above 930 ˚C with a lower uncertainty than our current procedures allowed. The cell was characterized with Type S and Pt/Pd thermocouples and with an HTPRT. The freezing plateaux were flat within 0.01 ˚C and lasted up to 1 h with a repeatability of 0.02 ˚C. The temperature of the cell was determined with a standard uncertainty of 0.04 ˚C. Hence, the copper cell was found to be superior to the comparator furnace for the calibration of platinum-based thermocouples because of the significant decrease in the uncertainty that it provides. An analysis was also carried out on the calibration of Pt/Pd thermocouples, and it was found that the combined use of the potassium GCHP and the Cu fixed-point cell is adequate to exploit the potential of these sensors in the range from 420 °C to 1,084 °C. A comparison with a fixed-point calibration was also made which gave rise to agreement within 0.07 ˚C between the two approaches.     

新型高分辨率紫外-可见成像光谱仪波长定标系统设计

限于常规波长定标的局限性,构建了高分辨率紫外-可见成像光谱仪波长定标装置.该系统主要由具有高稳定性的300W氙灯系统、前置施瓦兹型聚光镜、高光谱分辨力的中阶梯光栅单色仪以及后置光学系统组成.利用ZEMAX光学设计软件,对该中阶梯光栅单色仪光学系统进行了优化设计.对设计结果进行了分析,设计结果表明,所设计的高分辨率紫外-可见成像光谱仪波长定标装置满足设计指标要求,扫描光谱范围270～500 nm,光谱分辨力小于0.05 nm,波长精度小于0.05 nm.     

Lowering the UV Absorbance Detection Limit in Capillary Zone Electrophoresis Using a Single Linear Photodiode Array Detector

A new approach for lowering the UV absorbance detection limit in capillary electrophoresis is presented. This approach involves the use of a photodiode array in which each of the diodes in the array is treated as an independent detector. Over the course of a run, therefore, an electropherogram is generated for each diode in the array. Averaging the electropherograms generated from 1500 diodes in a diode array resulted in a signal-to-noise ratio 85 times that of an electropherogram generated from any one diode in the array. These signal-to-noise improvements are discussed, and the detection limits are compared to the detection limits obtained from a commercial single-point detector. The array detector improves the detection limit by a factor of 3.8 (±0.4).     

线列阵在密闭管中的自由场校准

由于拖曳线列阵很长，工作频率很低，用常规的自由场方法是很难对其进行校准的。本文提出了一种在密闭管中测量线阵的自由场复数灵敏度和指向性图的方法。已经开发了一个初型校准系统，系统的频率范围从２０Ｈｚ到６００Ｈｚ，管中所得的测量结果与理论曲线符合很好。因此，线列阵管中校准方法是一种在低频情况下校准线列阵的十分有效的方法。     

接收声基阵相位一致性校准研究

现代声纳系统中普遍采用由多个阵元组成的基阵接收信号并进行处理.在基阵的实际应用中,阵元的相位一致性是一项重要技术参数,研究基阵的相位校准方法用于相位补偿有重要的理论意义.文中主要研究了一种基于非线性最小二乘估计的相位一致性校准方法,此校准方法无需知道确切的声源位置,可在不满足远场条件的实验环境中进行,且适用于任意需要测量阵元间相位一致性的面阵或线阵.通过MATLAB对一均匀线阵进行了仿真,验证了此算法估计相位一致性和声源位置的有效性,最后应用此校准方法在水池中对一均匀线阵进行了验证性的实验,再次验证它的有效性与可行性.     

基于SPD的物体色快速分光测试系统设计

根据光度学与色度学理论，采用国际照明委员会（CIE）推荐的d/8标准照明／观察几何条件，应用自扫描光电二极管阵列（SPD）作为乐电探测器，设计了由积分球，脉冲光源，多色仪，光电放大与A／D转换器以及专用计算机等部分组成的双光路多通道物体表面色全光谱快速测试系统，该系统单次测色周期小于1秒，对陶瓷白板的测量精度（色度坐标）优于0．0003，重复性达到0．0001，满足了快速又准确的分光测色要求。     

太赫兹阵列探测器响应度校准溯源研究

提出了一种太赫兹阵列探测器响应度校准溯源方法。首先,使用阵列探测器的每一像元对太赫兹辐照场中心进行逐一扫描,识别有效像元、死像元和过热像元,并对有效像元响应值进行归一化处理,获得阵列探测器的相对辐照度响应值。其次,使用中心像元对太赫兹辐照场进行扫描测量,扫描总面积大于太赫兹光斑尺寸,保证太赫兹功率被完整测量,获得中心像元与其他有效像元的太赫兹功率响应值。最后,用标准太赫兹功率计标定高莱功率计,扩展太赫兹功率校准量限,实现微瓦级太赫兹辐射功率测量溯源,用高莱功率计测得的太赫兹辐射源总功率对阵列探测器测得的积分响应值进行校准,得到阵列探测器辐照度响应绝对值。对探测器进行测量校准和不确定度分析,测得辐照度响应度的相对扩展不确定度为Urel=20%(k=2),测量结果可溯源至国家太赫兹辐射功率标准。     

非线性传感器静态特性评估的极限点法

基于对测量过程、测量误差的认识，提出了一种利用极限点法评估非线性传感器静态特性的一种新方法。给出了利用该方法评估非线性传感器的两种模型。并以一电涡流式非线性位移传感器的标定数据进行了计算、分析。     

Radiometric Calibration Tracking of the Vacuum-Ultraviolet Spectrometer SUMER During the First Year of the SOHO Mission

Detailed radiometric calibration tracking of the vacuum-ultravioletspectrometer SUMER (from solar ultraviolet measurements of emittedradiation) was performed during the first year of the Solar andHeliospheric Observatory (SOHO) mission and will continue. Inview of the flight history of many previous solar UV instruments, thestability of calibration of the extreme-ultraviolet instruments on SOHOhas been a major concern. Results obtained during the first year ofoperation show that excellent radiometric stability has been achievedwith SUMER. These results were accomplished by stringentcleanliness and contamination-control procedures during all phases ofthe project. We describe the strategy and results of the in-flightcalibration tracking program performed with SUMER.     

Uncertainty Budgets for Calibration of Radiation Thermometers below the Silver Point

Below the freezing point of silver, radiation thermometers are generally calibrated by implementing the multi-point interpolation method using blackbody measurements at three or more calibration points, rather than the ITS-90 extrapolation technique. The interpolation method eliminates the need to measure the spectral responsivity and provides greater accuracy at the longer wavelengths required below the silver point. This article identifies all the sources of uncertainty associated with the interpolation method, in particular, those related to the reference blackbody temperatures (either variable-temperature or fixed-point blackbodies) and to the measured thermometer signals at these points. Estimates are given of the ‘normal’ and ‘best’ uncertainties currently achievable. A model of the thermometer response is used to propagate all the uncertainties at the reference points and provide a total uncertainty at any temperature within the calibration range. The multi-point method has the effect of constraining the total uncertainty over this range, unlike the ITS-90 technique for which the uncertainties propagate as T ². This article is a joint effort of the working group on radiation thermometry of the Consultative Committee for Thermometry (CCT), summarizing the knowledge and experience of all experts in this field.     

测压铜球准动态校准实践

简要介绍了测压铜球的工作原理、使用方法及发展过程,阐明了测压铜球准动态校准的含义及其实现方法.分析了准动态校准铜球压力对照表的编表误差,根据大量的动标数据分析了准动态校准压力对照表适用的膛压信号上升时间的变化范围.结合动标数据分析,给出了被测压力上升时间变化时铜球查表压力的修正公式.说明了测压铜球作温度修正的必要性及实用的修正方法.     

特殊结构露点传感器的校准特点

露点仪、露点传感器作为环境湿度的检测仪器,广泛使用于工农业生产、工业自动化和生活的各个领域。本文通过对露点传感器校准的现状分析,指出了目前的校准方法中存在的尚不具体明确之处。本文分析了特殊露点传感器结构原理,由此改进了特殊结构露点传感器的校准方法。