A hybrid radiation detector based on a plasma display panel

Recently, large-area image detectors have been investigated for X-ray imaging in medical diagnostic and other applications. In this paper, a new type of radiation detector is described, based on the integration of a photoconductor into a plasma display panel (PDP). This device, called a hybrid PDP detector, should be quite inexpensive, because it can directly leverage off the fabrication and materials technologies widely used in plasma display panels. Also, these new radiation detectors should operate under the most challenging environmental conditions, because they are inherently rugged and radiation-resistant and insensitive to magnetic fields. In this paper, we describe a hybrid digital radiation detector device, based on plasma display. The PDP panel is 7 in. in size with a 1000-μm pixel pitch, and filled with 700 Torr of Xe gas; the hybrid PDP panel is of the same structure, except for the photoconductor deposit. The glass absorption, dark current, X-ray sensitivity, and linearity as a function of electric field were measured to investigate its electrical properties. From the results, stabilized dark current density and significant X-ray sensitivity were obtained with both panels; however, the hybrid PDP detector showed better characteristics than the PDP detector. It also had good signal response and linearity. The hybrid digital radiation detector device based on a plasma display seems to be a promising technology for use in radiology and dynamic moving imaging.     

Radiative transfer. II. Impact of meteorological variables and surface albedo on atmospheric optical properties retrieved from ground-based multispectral measurements

In a companion paper we describe a radiative transfer model and a consequent algorithm for retrieving atmospheric variables from ground-based multispectral measurements of direct solar irradiance. The accuracy of retrieved data depends on measured spectral irradiance as well as surface meteorological variables. Here we analyze the impact of the surface albedo on diffuse scattered solar irradiance in the Sun-sensor direction. We also investigate the impact of visibility on the retrieved spectral transmission function and optical thickness. We discuss the application of a spectrometric system, the passive pyrheliometric scanner (PPS), for the estimation of atmospheric turbidity and visibility. The spectral transmission of the atmosphere derived with the PPS for the Athens atmosphere and for different zenith angles is given. We present results of retrieved aerosol optical properties using as atmospheric turbidity those values estimated from the ground-based measurements of direct solar radiation with the aid of the PPS. It is shown that another application of the PPS may be the estimation of horizontal visibility.     

Inexpensive detector for terahertz imaging

Glow discharge plasma, derived from direct-current gas breakdown, is investigated in order to realize an inexpensive terahertz (THz) room-temperature detector. Preliminary results for THz radiation show that glow discharge indicator lamps as room-temperature detectors yield good responsivity and noise-equivalent power. Development of a focal plane array (FPA) using such devices as detectors is advantageous since the cost of a glow discharge detector is approximately $0.2-$0.5 per lamp, and the FPA images will be diffraction limited. The detection mechanism of the glow discharge detector is found to be the enhanced diffusion current, which causes the glow discharge detector bias current to decrease when exposed to THz radiation.     

立体电视技术的发展趋势

立体电视可以使电视画面再现立体视觉的真实效果，不仅可以用于现代的信息交流和文化活动，而且也可用于科学技术研究，工业设计、建设和生产以及医学和军事事业等等，显著提高其工作效率，因此已成为新的电视技术的发展方向和研究重点。本文阐述了近几年来国内外在这一方面的研究进展，包括常说的立体电视STV及全息电视HTV，和立本视觉及立体电视的基本原理。     

A new rapidly absorbed paediatric paracetamol suspension. A six-way crossover pharmacokinetic study comparingthe rate and extent of paracetamol absorption from a new paracetamol suspension with two marketed paediatric formulations

The objective of this study was to compare the rate and extent of paracetamol absorption from the new Paracetamol pediatric suspension (PPS) with two marketed paracetamol suspensions: Children's panadol (CP) and Panodil baby & infant (PBI). The study also assessed the effect on paracetamol absorption of light-calorie, low-fat food consumed 2?h before dosing. Twenty eight male adult volunteers received a single oral dose of 1000?mg of paracetamol from each of three treatments, in both fasted and fed states according to a randomized, single-center, open-label, six-way crossover study design. PPS was bioequivalent to both CP and PBI for AUC(0-10 h), AUC(0-inf) and C(max) in both fasted and fed state. However, PPS had greater rate of paracetamol absorption and a faster speed of onset. T(max) for PPS was significantly shorter than for PBI in both fasted (p?=?0.0005) and fed state (p?=?0.0001). Median T(max) for PPS was also 10?min shorter than CP in fasted state. Time to reach minimum effective concentration (MEC) for PPS was significantly shorter than CP and PBI. Early paracetamol exposure of PPS was significantly higher than that of the two existing paracetamol products. Food had a significant effect in the early exposure and onset of therapeutic level of paracetamol from PPS. AUC(0-30 min) was significantly higher and time to reach plasma paracetamol at MEC level was significantly shorter than in the fasted state.     

Development of a New InGaAs Radiation Thermometer at NMIJ

The first InGaAs radiation thermometer at NMIJ was developed more than ten years ago as a standard radiation thermometer operating from 150 to 1,100°C. Its size-of-source effect (SSE) was as large as 1% from 6 mm in diameter to 50 mm in diameter. The new thermometer has an SSE of 0.3%. The reason for the error in measuring the SSE of InGaAs thermometers was also found. The new thermometer at first suffered from nonlinearity and the distance effect (DE). These deficiencies arose from the misalignment of optics inside the thermometer and were solved by increasing the detector size from 1 mm in diameter to 2 mm in diameter. Unfortunately, the detector of 2 mm diameter had a smaller S/N ratio than that of the 1 mm one at the indium (In) point. The final design uses a detector of 1 mm diameter, but the radiation is focussed on a smaller area of the detector. The new thermometer is smaller and lighter than preceding designs and other standard InGaAs radiation thermometers. The temperature of the main part of the instrument, including the filter, the detector, and the preamplifier board, is controlled at 30°C. In addition to the calibration with the six fixed points of copper (Cu), silver (Ag), aluminum (Al), zinc (Zn), tin (Sn), and indium (In), the linearity from the In point to the Cu point, the SSE, the DE, and the spectral responsivity were measured.     

SENTIRAD—An innovative personal radiation detector based on a scintillation detector and a silicon photomultiplier

The alarming personal radiation detector (PRD) is a device intended for Homeland Security (HLS) applications. This portable device is designed to be worn or carried by security personnel to detect photon-emitting radioactive materials for the purpose of crime prevention. PRD is required to meet the scope of specifications defined by various HLS standards for radiation detection. It is mandatory that the device be sensitive and simultaneously small, pocket-sized, of robust mechanical design and carriable on the user's body. To serve these specialized purposes and requirements, we developed the SENTIRAD, a new radiation detector designed to meet the performance criteria established for counterterrorist applications. SENTIRAD is the first commercially available PRD based on a CsI(Tl) scintillation crystal that is optically coupled with a silicon photomultiplier (SiPM) serving as a light sensor. The rapidly developing technology of SiPM, a multipixel semiconductor photodiode that operates in Geiger mode, has been thoroughly investigated in previous studies. This paper presents the design considerations, constraints and radiological performance relating to the SENTIRAD radiation sensor.     

可调制激光器的红外探测器响应测试系统

为了解决红外探测器生产、科研和测试中对响应均匀性,一致性和成品率的要求,用可调制半导体激光器替代黑体辐射源,设计了一套红外探测器表面响应测试系统.该系统应用计算机技术控制二维扫描平台,完成探测器平面的响应数据采集,通过VB调用MATLAB三维图形输出技术,直观的反映出探测器表面的响应情况.该系统自动完成整个测试过程,测试精度达到了0.001 2V,为探测器的自动化检测和科研提供了先进的方法和测试平台.     

无人值守核辐射监测系统研究

介绍了一套无人值守核辐射监测系统,其包括前端辐射探测器、数据传输链路和监控报警终端3个主要组成部分,研究了各个组成部分的关键技术环节和简要设计方案.     

玻璃纤维织物/聚苯硫醚粉叠层模塑工艺与性能

研究聚苯硫醚(PPS)树脂粉与玻璃纤维织物(GF)叠层模塑(粉末工艺)制复合材料的工艺与性能。测试各种工艺条件制GF/PPS层板的弯曲力学性能、动态力学性能,用扫描电镜(SEM)探查树脂对纤维的浸渍及纤维/基体的界面粘合情况。SEM分析结果表明,粉末工艺制得的PPS基复合材料呈现高的力学性能,是由于树脂对纤维的均匀浸渍和良好的纤维/基体的界面粘合。熔前热压、高温成型、退火处理是粉末工艺制高质量GF/PPS层板的工艺要点。      

China''''s High-technology Standards Development

There are several major technology standards, including audio video coding (AVS), automotive electronics, third generation (3G) mobile phones, mobile television, wireless networks and digital terrestrial television broadcasting, that have been released or are currently under development in China. This article offers a detailed analysis of each standard and studies their impact on China's high-technology industry.     

Gas pixel detectors for X-ray polarimetry applications

We discuss a new class of micro pattern gas detectors, the gas pixel detector (GPD), in which a complete integration between the gas amplification structure and the read-out electronics has been reached. An application-specific integrated circuit (ASIC) built in deep sub-micron technology has been developed to realize a monolithic device that is, at the same time, the pixelized charge collecting electrode and the amplifying, shaping and charge measuring front-end electronics. The CMOS chip has the top metal layer patterned in a matrix of 80 μm pitch hexagonal pixels, each of them directly connected to the underneath electronics chain which has been realized in the remaining five layers of the 0.35 μm VLSI technology. Results from tests of a first prototype of such detector with 2 k pixels and a full scale version with 22 k pixels are presented. The application of this device for Astronomical X-ray Polarimetry is discussed. The experimental detector response to polarized and unpolarized X-ray radiation is shown. Results from a full MonteCarlo simulation for two astronomical sources, the Crab Nebula and the Hercules X1, are also reported.     

Investigations of the spatial distribution of the energy characteristics of plasma radiators for a system of assurance of uniformity of measurements in nanolithography

A comparator that incorporates an imaging system and a position-sensitive detector is developed. The comparator supports the formation of spectro-zonal images with calibration in units of radiance and radiant intensity through the use of synchrotron radiation. A comparator is needed to obtain information about the distribution of the radiance of plasma radiators used in nanolithography in the area of extremal vacuum ultraviolet radiation. __________ Translated from Izmeritel’naya Tekhnika, No. 5, pp. 41–45, May, 2007.     

Frequency Modulation Multiplexing for Simultaneous Detection of Multiple Gases by use of Wavelength Modulation Spectroscopy with Diode Lasers

Modulation frequency multiplexing provides a straightforward method, analogous to television or radio broadcasting, for performing simultaneous detection of multiple gases by use of wavelength modulation spectroscopy with diode lasers. When fiber-optic coupled lasers are used, our approach guarantees that all beams transit the same optical path and impinge on the same detector. Each laser is modulated at a different frequency and the detector output is processed by a set of lock-in amplifiers, one for each laser, to measure the absorbance encountered by each laser.     

Photocatalytic performance of rich OVs-BiOCl modified by polyphenylene sulfide

Introduction of oxygen vacancies (OVs) on the surface of photocatalyst has been proved to be a potent avenue to improve photocatalytic capability by accelerating the segregation of photoactivated carriers and creating a defect energy level. In this presentation, a facile hydrothermal approach was performed to fabricate polyphenylene sulfide (PPS)/OVs-BiOCl composites to further improve the catalytic capability of OVs enriched BiOCl. The successful construction of rich OVs in BiOCl was firmly confirmed by X-ray photoelectron spectroscopy (XPS) and low- temperature electron spin resonance (ESR). Surface photovoltage spectrum (SPS) and electrochemical characterization display that the existence of PPS in the synthetic system dramatically affects the surface states of BiOCl, expediting the segregation of photoinduced carriers. Photocatalytic capacity of PPS/OVs-BiOCl was examined by disintegration of perfluorooctanoic acid (PFOA), rhodamine B (RhB) and tetracycline (TC). PPS surface modification can significantly improve the photoactivity of OVs-BiOCl toward destruction of PFOA, RhB and TC. Interestingly, when mass ratio of PPS/BiOCl is 0.5%, the degradation capacity of PPS/OVs-BiOCl for decontamination of RhB and TC is 4.25 and 3.10 -fold higher than that of OVs-BiOCl, respectively. In consideration of the observations, the photocatalytic enhancement mechanism for PPS/OVs-BiOCl was elaborated.     

聚苯硫醚结晶的研究现状

聚苯硫醚(PPS)具有优异的耐化学腐蚀性能、热稳定性、阻燃性和电绝缘性,在汽车、石油化工、电子电器、高温过滤等领域具有广泛的应用.由于PPS是半结晶性聚合物,结晶过程对PPS材料的各种性能具有重要的影响.阐述了PPS结晶的研究现状以及PPS结晶过程中的影响因素,在改善PPS材料力学性能方面介绍了共混/复合PPS材料结晶对结构与性能的影响,指出了研究PPS结晶对提高其性能的重要性.     

目标红外涂料隐身技术评判标准研究

隐身涂料在红外隐身技术的研究中占据重要位置.从涂料的隐身机理出发,以目标与背景的辐射对比度小于0.02作为红外隐身的评判标准,提出了一种关于涂料红外隐身技术的新的研究方向,并结合红外探测系统作用距离检验了这个评价标准.研究发现,考虑目标红外隐身时,不能盲目降低目标表面发射率.当辐射对比度减小到0.02时,作用距离比原先降低了71.4%.     

Analysis of the expected AGIPD detector performance parameters for the European X-ray free electron laser

A review of the parameters of the AGIPD detector planned to be used on the SASE 1 and SASE 2 beamlines of the European XFEL is presented. For both Coherent X-ray Diffraction Imaging (CXDI) and X-ray Photon-Correlation Spectroscopy (XPCS), the required detector noise level and dynamic range are evaluated from signal and background simulations on a per instrument basis. A worst case scenario of accumulated dose is computed in order to evaluate the required detector radiation hardness. Finally, acknowledging a mismatch between pixel size requirement and technological feasibility in the case of XPCS, the possibility to aperture the pixel in order to match the size requirement is presented and discussed.     

The Candela and Photometric and Radiometric Measurements

The national measurement system for photometric and radiometric quantities is presently based upon techniques that make these quantities traceable to a high-accuracy cryogenic radiometer. The redefinition of the candela in 1979 provided the opportunity for national measurement laboratories to base their photometric measurements on optical detector technology rather than on the emission from high-temperature blackbody optical sources. The ensuing technical developments of the past 20 years, including the significant improvements in cryogenic radiometer performance, have provided the opportunity to place the fundamental maintenance of photometric quantities upon absolute detector based technology as was allowed by the 1979 redefinition. Additionally, the development of improved photodetectors has had a significant impact on the methodology in most of the radiometric measurement areas. This paper will review the status of the NIST implementation of the technical changes mandated by the 1979 redefinition of the candela and its effect upon the maintenance and dissemination of optical radiation measurements.     

A new rapidly absorbed paediatric paracetamol suspension. A six-way crossover pharmacokinetic study comparingthe rate and extent of paracetamol absorption from a new paracetamol suspension with two marketed paediatric formulations

The objective of this study was to compare the rate and extent of paracetamol absorption from the new Paracetamol pediatric suspension (PPS) with two marketed paracetamol suspensions: Children’s panadol (CP) and Panodil baby & infant (PBI). The study also assessed the effect on paracetamol absorption of light-calorie, low-fat food consumed 2?h before dosing. Twenty eight male adult volunteers received a single oral dose of 1000?mg of paracetamol from each of three treatments, in both fasted and fed states according to a randomized, single-center, open-label, six-way crossover study design. PPS was bioequivalent to both CP and PBI for AUC_{0–10 h}, AUC_0–inf and C_max in both fasted and fed state. However, PPS had greater rate of paracetamol absorption and a faster speed of onset. T_max for PPS was significantly shorter than for PBI in both fasted (p?=?0.0005) and fed state (p?=?0.0001). Median T_max for PPS was also 10?min shorter than CP in fasted state. Time to reach minimum effective concentration (MEC) for PPS was significantly shorter than CP and PBI. Early paracetamol exposure of PPS was significantly higher than that of the two existing paracetamol products. Food had a significant effect in the early exposure and onset of therapeutic level of paracetamol from PPS. AUC_{0–30 min} was significantly higher and time to reach plasma paracetamol at MEC level was significantly shorter than in the fasted state.