Quantum radiometry

We review radiometric techniques that take advantage of photon counting and stem from the quantum laws of nature. We present a brief history of metrological experiments and review the current state of experimental quantum radiometry.     

Absorption and reflection of infrared radiation by polymers in fire‐like environments

In large‐scale fires, the input of energy to burning materials occurs predominantly by radiative transfer. The in‐depth (rather than just surface) absorption of radiant energy by a polymer influences its ignition time and burning rate. The present investigation examines two methods for obtaining the absorption coefficient of polymers for infrared radiation from high‐temperature sources: a broadband method and a spectral method. Data on the total average broadband transmittance for 11 thermoplastics are presented (as are reflectance data), and the absorption coefficient is found to vary with thickness. Implications for modeling of mass loss experiments are discussed. Copyright © 2011 John Wiley & Sons, Ltd.     

Response and noise characteristics of small-sized inorganic and organic scintillation detectors measured with vacuum and solid-state photodetectors

Response and noise properties of scintillation detectors were investigated using a ¹³⁷Cs radioactive source. The experimental setup consisted of a scintillator, photodetector, amplifier, and spectrometric analog-to-digital converter. Small-sized, cubic crystals were manufactured of stilbene, p-terphenyl and thallium-doped cesium iodide, as well as of a plastic scintillator material based on polystyrene. Vacuum and solid-state photomultipliers and a silicon PIN photodiode were used as photodetectors. The energy equivalent noise was determined for all used photodetectors. The response of various scintillators when using vacuum and semiconductor photomultipliers was found to be closely similar.     

Synchronization for IR‐UWB System Using a Switching Phase Detector‐Based Impulse Phase‐Locked Loop

Conventional synchronization algorithms for impulse radio require high‐speed sampling and a precise local clock. Here, a phase‐locked loop (PLL) scheme is introduced to acquire and track periodical impulses. The proposed impulse PLL (iPLL) is analyzed under an ideal Gaussian noise channel and multipath environment. The timing synchronization can be recovered directly from the locked frequency and phase. To make full use of the high harmonics of the received impulses efficiently in synchronization, the switching phase detector is applied in iPLL. It is capable of obtaining higher loop gain without a rise in timing errors. In different environments, simulations verify our analysis and show about one‐tenth of the root mean square errors of conventional impulse synchronizations. The developed iPLL prototype applied in a high‐speed ultra‐wideband transceiver shows its feasibility, low complexity, and high precision.     

Synchrotrons radiation stability measurement and improvement

In the 3rd generation synchrotron light source,beside the orbit,air disturbance and ground vibration also could affect the position stability of photon beam in synchrotrons radiation measurement.In the condition of implementation of orbit feedback system at SSRF,the measured position stability of photon beam in synchrotrons radiation measurement station was presented in this paper.And then the improvement methods of position stability of photon beam were discussed.Finally the measured result was shown when the designed feedback system is implemented to improve the position stability of photon beam.     

Synthesis and degradation of agar‐carbomer based hydrogels for tissue engineering applications

Hydrogels studied in this investigation, synthesized starting from agarose and Carbomer 974P, were chosen for their potential use in tissue engineering. The strong ability of hydrogels to mimic living tissues should be complemented with optimized degradation time profiles: a critical property for biomaterials but essential for the integration with target tissue. In this study, chosen hydrogels were characterized both from a rheological and a structural point of view before studying the chemistry of their degradation, which was performed by several analysis: infrared bond response [Fourier transform infrared (FT‐IR)], calorimetry [differential scanning Calorimetry (DSC)], and % mass loss. Degradation behaviors of Agar‐Carbomer hydrogels with different degrees of crosslinkers were evaluated monitoring peak shifts and thermal property changes. It was found that the amount of crosslinks heavily affect the time and the magnitude related to the process. The results indicate that the degradation rates of Agar‐Carbomer hydrogels can be controlled and tuned to adapt the hydrogel degradation kinetics for different cell housing and drug delivery applications. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011     

水基气雾剂中右旋炔丙菊酯、右旋苯醚菊酯、氯菊酯气相色谱法测定

目的:建立水基气雾剂中右旋炔丙菊酯、右旋苯醚菊酯、氯菊酯的气相检测方法。方法:采用邻苯二甲酸二戊酯和邻苯二甲酸二丁酯两种物质作内标进行对比,丙酮作为溶剂,用HP-5的毛细管柱为分离柱,采用程序升温的方法进行分离,FID检测器,进样口温度300℃,检测器温度300℃,柱温初始180℃以20℃/min升温至280℃,保留5 min。结果:3种物质在标样与内标质量比1∶5~5∶1范围内呈良好线性关系,相关系数大于0.999,回收率为92.34%~105.12%,RSD为0.182%~0.649%。结论:此方法准确可靠,并且检测快速、高效,对原有方法进行补充。     

Lifetime extension of in‐core self‐powered neutron detector using new emitter materials

In this paper, new in‐core self‐powered neutron detector emitter candidate materials, ie, vanadium, cobalt, and silver, have been examined in their lifetimes compared with the commonly used rhodium emitter. Using a new quantitative lifetime evaluation model, the lifetimes of vanadium and cobalt were determined to be longer than that of rhodium, but these materials were also shown to have the disadvantage of low signal intensities. Under normal operating conditions, we showed that rhodium emitter can be used for 2 cycles of pressurized water reactors (PWRs) with lifetime of 4.35 years, whereas silver can be used for 5 cycles of PWRs with lifetime of 8.04 years. Three sensitivity tests were performed for rhodium and silver about (1) the emitter size, (2) the fuel assembly burnup, and (3) the emitter temperature variations. From the test results, we observed that the lifetimes of rhodium and silver emitters remained 2 and 5 cycles long, respectively. We concluded that silver can significantly extend the in‐core detector's lifetime in PWR operation.     

有机液体吸光度检测仪的开发应用

湿法冶金生产工艺中,有机萃取是常见的工艺,生产过程中有机液体的颜色及色深(吸光度),是工艺指标性参数,但是对于有机液体的在线测量,因缺乏成熟的仪器,目前大多靠人眼目测和实验室比对的方式。我们以比尔-朗伯定律为理论依据,通过对有机液体吸光度变化与光电吸收关系的研究,开发了有机液体吸光度检测仪,并投入了现场应用,取得了良好的效果。     

基于EJ299-33A探测器的核材料时间关联测量系统的时间分辨

n-γ的时间关联测量可提取核材料的质量、增殖因数，其中时间分辨是表征关联精度的1个重要指标。本文基于数字化数据获取与处理方法，对具有n-γ甄别能力的塑料闪烁体EJ299-33A探测器组成的核材料时间关联测量系统的时间分辨进行研究，采用⁶⁰Co与²²Na γ源进行了对比测量，分析了源对本征时间分辨的影响，进一步通过离线的条件加载反演，给出时间分辨的等效电子能量阈值依赖关系。通过对²⁵²Cf自发裂变时间关联谱的测量和解耦，讨论了时间分辨对不同符合事件的影响。结果表明：系统时间分辨随阈值增加而减少，在阈值为230 keVee时采用⁶⁰Co测量的结果约为560 ps，可满足核材料快时间符合测量的精度要求，而在相同条件下，由于正电子湮没位置的不确定性和延迟符合的影响，²²Na源测量的时间分辨展宽至816 ps；裂变事件时间关联测量中n-n符合受时间分辨的相对影响小于γ-γ符合。