A Tracker Prototype Based on Cathode Straw Tubes

A prototype of a 2D detector based on specially designed straw tubes with cathode data readout has been developed and tested. This detector exhibits comparable accuracies in measuring radial and longitudinal coordinates. Its rate capability is similar to the capabilities of traditional detectors whose tubes are smaller by half in diameter.     

Signal transmission lines for large-size segmented straw detectors

Lines for transmitting the signals of high-granulated coordinate straw detectors from the detector sensitive area to the remote readout electronics are simulated, and samples of these lines are investigated. The possibility of transmitting the signals using lines with a length of up to 2 m without distortions is shown. These lines can also be used to supply a high voltage of up to 3 kV to the straw segments with negligible leakage currents.     

Using the cathode surface of straw tube for measuring the track coordinates along the wire

The coordinate detectors based on straw tubes provide a high accuracy of the radial coordinate measurement using the drift time and a small amount of matter in the way of the measured particles. However, the measurement of the coordinate along the wire constitutes a problem. This paper proposes a method for measuring the hit coordinate along the wire with an accuracy better than 1 mm in a straw tube detector using the signals from the cathodes of the detector.     

基于磁感原理的结冰探测器参数计算方法

随着我国航空技术的迅速发展，防冰/除冰技术的研究越来越受到重视，系统中结冰探测器直接影响防冰/除冰的效果。文中对一种基于磁感原理的结冰探测器进行了分析，通过建模推导出相关参数的计算方法，并进行了仿真试验。笔者解决了结冰探测器基本设计参数计算的问题，为结冰探测器的设计提供了一种有效方法。     

基于红外焦平面阵列读出结构的非均匀校正算法

空间固定图案噪声严重影响了红外探测器的成像质量,它主要是由于焦平面阵列上各探测单元对于同一辐照的光电响应不完全一致所造成。另外,多通道图像数据采集电路的非均匀性更加重了这种噪声。本文提出了一种基于红外焦平面阵列读出结构的非均匀校正算法,它将校正过程分成两步。首先利用恒定统计方法滤除由通道放大器引起的固定图案噪声,然后再将处理结果通过改进的神经网络方法,进一步校正由探测器响应而产生的非均匀性。由于该算法是递推进行,并且具有收敛速度快、计算复杂度低等优点,因此易于工程实现。文中详细阐述了算法的基本原理及其流程,并用仿真数据和真实红外数据对算法性能进行验证,取得了较好的效果。     

A new position-sensitive silicon pixel detector based on bipolar transistors

A new type of detector of ionizing particles and radiations is described. The sensitive region of the detector, which is an array of bipolar transistors, is the collectors of these transistors, in which the primary signal of an ionizing particle is also preamplified. Using circuits of multiemitter transistors, it is very easy to branch the initial signal directly at the detector to several readout buses with equal signal levels in each bus. This possibility allows, in particular, the development of two-coordinate detectors with readout only on one side or detectors with an outputted readout triggering signal (self-triggering systems). Since 2005, several prototypes of such detectors have been produced in Russia. This paper presents their designs, some important elements of the manufacturing process, and the test results.     

A direct time measurement technique for determining the longitudinal coordinate in thin-walled drift tubes

Techniques for measuring the longitudinal coordinates in drift tubes are considered. It is shown that the use of the direct timing method to determine the longitudinal coordinates helps to obtain the longitudinal resolution several times better relative to the charge division method and is suitable for long tubes. The implementation of this method provides a means for designing coordinate detectors based on drift tubes with the two-dimensional readout and a high response speed, which will not be very complex.     

A general approach to low noise readout of terahertz imaging arrays

This article describes the theory and design of an ultra-low noise electronic readout circuit for use with room temperature video-rate terahertz imaging arrays. First, the noise characteristics of various imaging detectors, including low resistance bolometers and high resistance diodes are discussed. Theoretical approaches to white and 1/f noise mitigation are examined, and a corresponding low-noise readout circuit is designed, built, and tested. It is shown that the circuit is capable of achieving detector limited noise performance for use in room temperature terahertz imaging systems. A thorough noise analysis of the circuit provides the necessary information for applying the readout circuit to any type of imaging detector, and more generally, any measurement of small signals from various source impedances in the presence of white and 1/f noise. W-band measurements of an 8-element, high-resistance detector array, and a 32-element, low-resistance detector array demonstrate the usefulness of the readout circuit. Finally, recommended circuit configurations for various detectors in the literature are provided, with theoretical performance metrics summarized.     

Invited article: the fast readout low noise camera as a versatile x-ray detector for time resolved dispersive extended x-ray absorption fine structure and diffraction studies of dynamic problems in materials science, chemistry, and catalysis

Originally conceived and developed at the European Synchrotron Radiation Facility (ESRF) as an "area" detector for rapid x-ray imaging studies, the fast readout low noise (FReLoN) detector of the ESRF [J.-C. Labiche, ESRF Newsletter 25, 41 (1996)] has been demonstrated to be a highly versatile and unique detector. Charge coupled device (CCD) cameras at present available on the public market offer either a high dynamic range or a high readout speed. A compromise between signal dynamic range and readout speed is always sought. The parameters of the commercial cameras can sometimes be tuned, in order to better fulfill the needs of specific experiments, but in general these cameras have a poor duty cycle (i.e., the signal integration time is much smaller than the readout time). In order to address scientific problems such as time resolved experiments at the ESRF, a FReLoN camera has been developed by the Instrument Support Group at ESRF. This camera is a low noise CCD camera that combines high dynamic range, high readout speed, accuracy, and improved duty cycle in a single image. In this paper, we show its application in a quasi-one-dimensional sense to dynamic problems in materials science, catalysis, and chemistry that require data acquisition on a time scale of milliseconds or a few tens of milliseconds. It is demonstrated that in this mode the FReLoN can be applied equally to the investigation of rapid changes in long range order (via diffraction) and local order (via energy dispersive extended x-ray absorption fine structure) and in situations of x-ray hardness and flux beyond the capacity of other detectors.     

Frequency multiplexed superconducting quantum interference device readout of large bolometer arrays for cosmic microwave background measurements

A technological milestone for experiments employing transition edge sensor bolometers operating at sub-Kelvin temperature is the deployment of detector arrays with 100s-1000s of bolometers. One key technology for such arrays is readout multiplexing: the ability to read out many sensors simultaneously on the same set of wires. This paper describes a frequency-domain multiplexed readout system which has been developed for and deployed on the APEX-SZ and South Pole Telescope millimeter wavelength receivers. In this system, the detector array is divided into modules of seven detectors, and each bolometer within the module is biased with a unique ～MHz sinusoidal carrier such that the individual bolometer signals are well separated in frequency space. The currents from all bolometers in a module are summed together and pre-amplified with superconducting quantum interference devices operating at 4 K. Room temperature electronics demodulate the carriers to recover the bolometer signals, which are digitized separately and stored to disk. This readout system contributes little noise relative to the detectors themselves, is remarkably insensitive to unwanted microphonic excitations, and provides a technology pathway to multiplexing larger numbers of sensors.     

基于NANMAC热电偶的时间常数测试技术研究

本文介绍了热电偶时间常数的测试理论,提出了运用瞬态表面温度传感器动态校准系统实现对NANMAC热电偶时间常数的测试方法。该系统对红外探测器和热电偶进行了静态校准和动态校准,得到两者的温度一时间曲线。由于红外探测器的频率响应优于被校准热电偶的频率响应,因此,以红外探测器测得的值作为真值,用热电偶测得的值与红外探测器测得的值相比得到-条归-化的曲线,并由归-化曲线求得热电偶的时间常数。利用该方法对NANMAC热电偶进行时间常数的测试实验,得到了该热电偶的时间常数。实验结果表明：该时间常数测试方法是可行的,可以实现对微秒、毫秒量级热电偶的动态校准,这对于NANMAC热电偶温度传感器的研究和应用具有一定的参考价值。     

Development of advanced x-ray imaging crystal spectrometer utilizing a large area segmented proportional counter for KSTAR

An advanced x-ray imaging crystal spectrometer (XICS) for KSTAR tokamak has been developed by utilizing a segmented two dimensional (2D) position-sensitive multiwire proportional counter. The XICS for the KSTAR tokamak provides time-resolved measurements of the radial ion and electron temperature profiles, toroidal plasma rotation velocity, and ionization equilibrium. The segmented 2D detector with delay-line readout and supporting electronics has been adopted to improve the photon count rate capability. The current fabrication status of the XICS for the KSTAR tokamak and the first performance test results of the prototype segmented 2D detector are presented.     

激光干涉仪引力波探测器的基本光学结构

引力波是爱因斯坦广义相对论的重要预言,引力波探测是当代物理学最重要的前沿领域之一。以引力波探测为基础的引力波天文学是一门新兴的交叉科学,是对传统电磁辐射天文学的巨大拓展与补充。作为一种大型的精密光学仪器并作为引力波天文学研究的关键设备,激光干涉仪引力波探测器已在世界各地蓬勃发展起来,开辟了引力波探测的新时代。给出了激光干涉仪引力波探侧器的工作原理和基本光学结构,讨论了主要的性能参数,分析了光学镜的结构特点及测量方法。     

Determining the absolute efficiency of a delay line microchannel-plate detector using molecular dissociation

We present a method to measure the absolute detection efficiency of a delay-line microchannel-plate detector using the breakup of diatomic molecular ions. This method provides the absolute total detection efficiency, as well as the individual efficiency for each signal of the detector. The method is based on the fact that molecular breakup always yields two hits on the detector, but due to finite detection efficiency some of these events are recorded as single particles while others are detected in pairs. We demonstrate the method by evaluating the detection efficiency for both timing and position signals of a delay-line detector using laser-induced dissociation of molecular ions. In addition, the detection efficiency as a function of position has been determined by dividing the detector into sectors.     

Compensation of the shadowing error in three-dimensional imaging with a multiple detector scanning electron microscope

A method for three‐dimensional quantitative surface characterization for scanning electron microscopy is presented. The method used a quadruple scintillator detector developed by us. A surface reconstruction algorithm was performed by special software, with new algorithms for error compensation. Among these errors, detector shadowing was of particular importance. This was due to the disturbance in integration continuity when one or more detectors was screened from the flow of electrons. Several methods for the reduction of this error have been proposed and tested by us. The methods were based on software processing of complementary information, such as unshadowed detector signals, shadow depth and modified integration schemes.     

金属探测器在水射流切割中的应用研究

针对在高压水射流切割过程中可视性差,喷头极易与切割件产生硬性接触,造成损坏之问题。文中将金属探测器应用在高压水射流设备上,通过对金属探测器进行理论研究,使用等效阻抗法对金属探测器原理进行分析,选择适当的金属探测器调整参数后进行实验,最后检验了金属探测器安装在高压水射流切割设备并进行金属物件实际切割的效果,能够做到超前预警,从而保护了喷嘴,提高了作业效率。     

利用异形像元探测器的超分辨成像方法

随着光学成像全面进入光电数字成像时代,大多数成像系统的空间分辨率受限于探测器,所以提高探测器分辨率成为高分辨光电成像系统中的核心问题。而探测器的低分辨率主要是由于低采样频率和像元感光区的孔径效应而造成。最直接的解决方法就是减小像元尺寸,但会降低其他性能参数;针对最主要的限制因素——采样频率不足,目前多采用基于过采样原理的超分辨重建技术,通过提高探测器采样的频率来提高探测器的空间分辨率,但是其提升效果受到像元孔径效应的制约。为了进一步提高探测器受限的成像系统的空间分辨率,提出一种基于异形像元探测器的超分辨成像方法,将两列线阵异形像元探测器亚像元推扫实现像元细分,然后利用两列探测器所输出的灰度矩阵信息,重建出最终的高分辨图像。并分别通过理论评估和具体实验两方面验证该方法可以同时提高探测器的采样频率和截止频率,拓展带宽,从而实现高分辨率的目的。     

Scanning transmission X-ray microscopy with a fast framing pixel detector

Scanning transmission X-ray microscopy (STXM) is a powerful imaging technique, in which a small X-ray probe is raster scanned across a specimen. Complete knowledge of the complex-valued transmission function of the specimen can be gained using detection schemes whose every-day use, however, is often hindered by the need of specialized configured detectors or by slow or noisy readout of area detectors. We report on sub-50 nm-resolution STXM studies in the hard X-ray regime using the PILATUS, a fully pixelated fast framing detector operated in single-photon counting mode. We demonstrate a range of imaging modes, including phase contrast and dark-field imaging.     

Characterization of a 2D soft x-ray tomography camera with discrimination in energy bands

A gas detector with a 2D pixel readout is proposed for a future soft x-ray (SXR) tomography with discrimination in energy bands separately per pixel. The detector has three gas electron multiplier foils for the electron amplification and it offers the advantage, compared with the single stage, to be less sensitive to neutrons and gammas. The energy resolution and the detection efficiency of the detector have been accurately studied in the laboratory with continuous SXR spectra produced by an electronic tube and line emissions produced by fluorescence (K, Fe, and Mo) in the range of 3-17 keV. The front-end electronics, working in photon counting mode with a selectable threshold for pulse discrimination, is optimized for high rates. The distribution of the pulse amplitude has been indirectly derived by means of scans of the threshold. Scans in detector gain have also been performed to assess the capability of selecting different energy ranges.