A Two-Detector Single-Crystal Scintillation Autocorrelation Spectrometer with Rejection of Afterpulses

A two-detector single-crystal scintillation autocorrelation spectrometer with rejection of afterpulses has been developed. Afterpulses are rejected by the delayed coincidence method.     

光电倍增管的特性,结构及选取考虑

光电倍增管（ＰＭＴ）的独特优点,尤其是它极高的光探测灵敏度、低噪声和大的光敏区面积,使它作为高技术的测量设备中的首选光传感器,近年来得到了快速发展和广泛的应用,本文在简要地介绍了ＰＭＴ特性及工作原理的基础上,从如何选择和应用ＰＭＴ的角度,论述了几种新型ＰＭＴ打拿极结构与它们的应用领域,对ＰＭＴ光阴极类型、位置敏感ＰＭＴ以及ＰＭＴ的某些重要参数也进行了探讨。     

A Method to Improve Gamma Energy Resolution of BC-420 Type Organic Scintillation Detector

Instruments and Experimental Techniques - Currently, plastic (organic) scintillators are using in new type positron emission tomography (PET) devices such as J-PET. But, these type scintillators...     

A Large and Thin Scintillation Plate as a Charged-Particle Coordinate Detector

A new method of light collection in a scintillation plate with wavelength-shifting fibers is described. Using this method, it is possible to determine the coordinates of charged particles traversing the plate. The spatial resolution of the system is comparable to the scintillation-plate thickness and competitive in comparison with the resolution of wire chambers. The results of the experimental testing are presented.     

A Scintillation Detector of Protons and Neutrons, Products of a ddReaction

A detector of 3.02-MeV protons and 2.45-MeV neutrons is designed for experiments with the injection of deuterium atomic beams in a Gas-Dynamic Trap facility. An organic scintillator and a phototube with a fine-mesh dynode system are used in the sensor. The detector is operated in the mode of single-particle counting; the time resolution is 20 ns. Discrimination between different particles is effected by using a controlled damper that shuts off the proton flow and also by analyzing pulse-height spectra. The sensor is inserted in a vacuum chamber; the rotating mechanism of the sensor and location of the ports in the facility enables measurements along the plasma column.     

A Matrix Carbon Detector for Measuring the Energy Flux of a High-Power Beam of Hydrogen Ions

A matrix detector consisting of small calorimeters based on УПВ-1 pyrolytic carbon is described. The detector allows measurements of the spatial distribution of the energy flux of a high-power hydrogen ion beam to be taken over its cross section. Each calorimeter occupies an area of 4 cm², and the area of its working body is 0.25 cm². An unambiguous relation between the heat flux value, the irradiation time, and the calorimeter temperature is established by calculations. The calorimeter measurement error was estimated at ～4%, and the spread of the sensitivity coefficients between the calorimeters was 5–6% (1σ). The detector was used to measure the distribution of the energy flux of hydrogen ions over the cross section of the “scanned” beam 10 cm in diameter from a high-current accelerator of the НГ-12И facility.     

The Energy Characteristics of a Multichannel Scintillation Spectrometer

Instruments and Experimental Techniques - A multichannel scintillation spectrometer with a thickness of 2.5X0 has been calibrated on a secondary electron beam with energies of 23?280 MeV at...     

Energy Characteristics of the Two-Channel Scintillation Spectrometer

Instruments and Experimental Techniques - A two-channel scintillation spectrometer with a thickness of 0.5X0 was calibrated using cosmic muons and a beam of secondary quasi-monochromatic electrons...     

A Digital Scintillation Detector for the MEDIANA Medical Diagnostic Station

A digital position-sensitive X-ray imaging scintillation detector has been designed for the MEDIANA medical diagnostic station of the Kurchatov Synchrotron Radiation Center (the Kurchatov Institute). A single-crystal CsI(Tl) scintillator 8 mm thick is used as a screen with approximately 100% detection efficiency for X rays with energies as high as 100 keV. A CCD matrix of dimensions 1024 × 1024 pixels is the photodetector. The spatial resolution is five line pairs per mm in a field of vision of 35 × 35 mm for 100-keV X rays.     

Afterpulses in a proportional counter with various cathode materials

The results of an investigation of afterpulses arising in a proportional counter due to the photoeffect on the cathode are presented. It was found that, as the gas amplification changes, the amplitude of afterpulses becomes proportional to the square amplitude of the primary pulse, and that the coefficient of proportionality can serve as a criterion for comparing the emission properties of cathodes made of various materials. Such a comparison was performed for cathodes of stainless steel, copper, beryllium and aluminum alloys. It was found that phosphatizing of aluminum produces a coating, which essentially reduces the photoeffect on the cathode. Unlike anodic oxidation, a phosphate layer possesses sufficient conductivity that prevents spontaneous discharges in a counter caused by accumulation of electrical charges followed by an electrical breakdown of the coating layer.     

Energy and Spatial Resolution of a Large-Volume Liquid-Scintillator Detector

The energy and spatial resolution of a large-volume liquid-scintillator detector has been investigated. The relations have been derived, which allow the energy and spatial resolution of the detector to be estimated without modeling. The calculations involve the light-collection functions of the detector obtained either by the Monte Carlo method or in the measurements taken with radiation sources. The relations are verified with the experimental data of the CTF (Counting Test Facility) detector, which is a prototype of the new Borexino detector for solar neutrinos. An event reconstruction technique using charge and time data from the photomultiplier tubes (PMTs) is analyzed with the help of these relations in order to improve the detector resolution. Algorithms for the energy and coordinate reconstruction of individual events are presented.     

A Charged-Particle Detector Based on Proportional Tubes with a Segmented Cathode and Cathode Readout

A charged-particle detector based on proportional tubes with cathode readout is described. The cathode is sectionalized into 2.2 × 2.2-cm pads. The detector was tested on high-energy particle beams. At an anode-to-cathode distance of 1.1 cm, the spatial resolution was 1.25 mm along the anode wire. A simulation model of the detector on the basis of the measured pad-response function was proposed, compared to the experimental data, and used to calculate the two-track resolution. The detector can be used in various experiments as a large-area multiparticle two-coordinate detector.     

A Ring Neutron Detector for a Time-of-flight Diffractometer Based on Linear Scintillation Detectors with Silicon Photomultipliers

A ring neutron detector has been developed for a time-of-flight diffractometer based on linear scintillation detectors. Light is transported over an organic glass light guide with a diffuse reflector. This scheme makes it possible to collect more photons than are collected in detectors based on wavelength-shifting fibers and to use avalanche photodiodes (SiPMs) instead of photomultiplier tubes. Testing confirmed that these detectors could be used as an alternative for widely used proportional neutron counters filled with ³He.     

Setting of the Predefined Multiplier Gain of a Photomultiplier

A method for setting the predefined PMT gain with high precision is described. The method implies a minimal participation of the operator. After the rough initial gain setting, the automated system adjusts the high voltage so as to set the PMT gain within a predefined precision (up to 2%). This method has been successfully applied at the Borexino PMT test facility at LNGS for gain adjustment of the 2000 photomultipliers for the Borexino solar neutrino detector     

使用CCD进行动态高精度角度测量

本文讨论了使用线阵CCD作为光电接收器的高精度动态测角系统的原理,结构及系统的精度,最后对衍射及滤波对测量精度的影响也进行了分析。     

太阳能真空集热管弹簧卡的改进

目前国内太阳能真空集热管的生产,在生产工艺、产品开发和生产管理上都普遍存在着水平提升的要求。本文从太阳能真空集热管内的弹簧卡的安装工艺和使用角度出发,论述了弹簧卡结构形状改进的必要,并提出了改进的方法。     

Ultrasonic Measuring Facility. Detector of Acoustic Signals

The schematic electric circuit of a detector of acoustic signals for an ultrasonic measuring facility is given.     

Ultrasonic Measuring Facility. Detector of Acoustic Signals

The circuit diagram of a detector of acoustic signals for an ultrasonic measuring facility is discussed.     

Measuring the Energy and Amplitude of Pulse Acoustic-Emission Signals

A new method for measuring the amplitude and energy of pulse acoustic-emission signals is proposed. It is applicable in a broad dynamic range of pulse amplitudes (over 120 dB).     

光电式子弹速度及动能测试系统研究

文中介绍了光电式子弹飞行速度及动能测试系统。该系统采用红外光敏检测原理,可自动检测子弹的飞行速度及子弹动能。测试过程中,由于子弹速度不受仪器等其它因素的影响而衰减,抗干扰能力强,精度高,数据可靠。测试结果表明系统基本性能达到和超过了原设计指标。