Ultrahigh-resolution spin-resolved photoemission spectrometer with a mini Mott detector

We have developed an ultrahigh-resolution spin-resolved photoemission spectrometer with a highly efficient mini Mott detector and an intense xenon plasma discharge lamp. The spectrometer achieves the energy resolutions of 0.9 and 8 meV for non-spin-resolved and spin-resolved modes, respectively. Three-dimensional spin-polarization is determined by using a 90° electron deflector situated before the Mott detector. The performance of spectrometer is demonstrated by observation of a clear Rashba splitting of the Bi(111) surface states.     

The time resolution of a prototype neutron detector

The time characteristics of a prototype neutron detector designed for measuring the time of flight and determining the coordinate of the interaction point of a high-energy neutron on the detector have been investigated on cosmic rays. The time resolutions of the prototype neutron detector and the monitoring system are σ ≈ 0.7 and 0.2 ns, respectively.     

The time characteristics of a single module of the neutron detector

The time characteristics of the scintillation plate that is an element of the neutron detector designed for measuring the energy of a neutron by its time of flight and determining the coordinate of the point of its interaction with the detector have been investigated on cosmic rays. The time resolutions of the neutron detector element measured with P9814B and FEU-63 photomultiplier tubes are σ ≈ 0.14 and 0.29 ns, respectively.     

Implementation of fast-neutron radiography on a stationary neutron generator using a CCD detector

Radiographic images in ≈3.5-MeVdd-neutrons are obtained using a CCD detector for visualization. It is shown that radiographic images with a space resolution of ≤1 mm and 150-mm field of view at an exposure time of ≈5 min can be produced. Features of the radiography with a point neutron source of the generator type are considered.     

A thermal neutron detector based on single-crystalline silicon

It is shown that a change in the specific electrical conductivity (SEC) in silicon single crystals after irradiation and radiation defect annealing is directly proportional to the thermal neutron fluence. This fact is used as a basis of a method for measuring the neutron flux. In this case, the proportionality factor is dependent on the neutron spectrum, being independent of the initial SEC, which significantly simplifies detector calibration. In measurements of the thermal neutron fluence in terms of relative and absolute units, the rms was 4 and 8%, respectively.     

Development of a thermal neutron detector based on scintillating fibers and silicon photomultipliers

We propose a technique for thermal neutron detection, based on a (6)Li converter placed in front of scintillating fibers readout by means of silicon photomultipliers. Such a technique allows building cheap and compact detectors and dosimeters, thus possibly opening new perspectives in terms of granular monitoring of neutron fluxes as well as space-resolved neutron detection.     

Time delay of a field-breakdown triggered vacuum switch with flat electrodes

Triggered vacuum switch (TVS) is one of the important switch apparatuses in the field of pulsed power system. The field-breakdown will bring long lifetime of TVS under rated working conditions. However, the load of trigger will be heavy, leading to the large time delay and jitter time. In this paper, a field-breakdown TVS sample with flat electrodes was fabricated and its time delay was tested. Initial plasmas play an important role in the turning-on process of TVS, so the time delay from the control signal to the switching-on of TVS is discussed in the trigger system time, the motion time and the collapse time, where the motion time and the collapse time are the needed time for the generation and development of the initial plasmas. Test results show that, under positive working mode, the trigger system time is about 34–36 μs with positive trigger pulse, while 39–41μs with negative trigger pulse, which prove that the polarities of trigger pulse have nothing to do with the trigger system time almost, and the long trigger system time is mainly owing to the limited performances of trigger pulse transformer. The motion time is about 50 ns and almost stable, due to the definite trigger gap. The collapse time is about 100–300 ns, which is decreased with the rise up of main gap voltage, exponentially. In negative working mode, both of the motion time and collapse time are about 10 μs, due to the ions of initial plasmas becoming the main moving particles in the main gap, no longer the electrons as positive working mode.     

超声波物位仪在真空处理料仓检测中的应用

介绍了E+H公司非接触式单探头超声波物位检测仪在攀钢RH-MFB真空处理装置铁合金料仓中的应用,阐述了检测仪的原理、功能特点及其安装要求。实践证明该检测仪具有安装简便、维护量少、故障率低、精度高(其分辨率在±5mm内)、标定简单、安全可靠等优点,具有推广价值。     

The full-voltage effect and the optimal modes of the pulsed conditioning of electrodes in a vacuum

The effect of full voltage on the efficiency of the pulsed conditioning of electrodes in a vacuum is assessed. The efficiency of optimal conditioning modes, estimated from the quality of the cathode surface relative to gaps of centimeter length and long-acting voltage, increases by more than two orders of magnitude when the pulse duration and interelectrode gap are reduced. An increase of up to one order of magnitude is achieved by reducing the gap width to micron sizes during conditioning. The efficiency increases by a factor of as much as 30 by reducing the pulse duration and raising the optimal regimes pulse power.__________Translated from Pribory i Tekhnika Eksperimenta, No. 2, 2005, pp. 92–94.Original Russian Text Copyright © 2005 by Emelyanov, Emelyanova, Kubyshkina.     

带有BA功能的汽车真空助力器性能检测装置研究

通过对带有刹车辅助(BA)功能的真空助力器结构的研究,在以往真空助力器检测台的基础上,研制出了带有BA功能的真空助力器性能检测装置.检测装置的设计包括硬件部分和软件部分.硬件部分包括检测台机械部分、控制部分、数据采集部分、驱动和连接部分等.软件部分是检测台的核心,采用Delphi作为编程语言,编制人性化操作界面,针对带有BA功能的真空助力器的特性,设置对应的检测项目.通过试验对该检测装置进行了验证.     

Adaptation of an ultrahigh vacuum angle-resolving photoemission chamber for sample manipulation and rotation

A sample-manipulator attachment to a UHV angle-resolving photoemission system is described which permits the sample to be rotated azimuthally and to be transported to a LEED/Auger optics. The manipulator may be assembled from readily available commercial parts.     

Highly absorbing gadolinium test device to characterize the performance of neutron imaging detector systems

We report on the fabrication and application of a novel neutron imaging test device made of gadolinium. It is designed for a real time evaluation of the spatial resolution, resolution direction, and distortions of a neutron imaging detector system. Measurements of the spatial resolution of (6)LiF doped ZnS scintillator screens with different thicknesses and of imaging plates were performed. The obtained results are in good agreement with comparison measurements using the standard knife edge detection method.     

基于模块化设计的ITER真空室中子屏蔽结构组件数字化

ITER真空室中子屏蔽结构为多组件结构体.根据真空室双层壳体之间的空间结构和平面结构特征,运用模块化设计概念和相关的CAD设计软件,提出了基于位置特征和结构特征的零件标签设定方法,并将设计信息库、屏蔽组件实体库及其结构仿真形成一个完整的数字化设计系统,并发展了虚拟装配技术.结果,建立了可供编辑管理的数据信息库和实体模型库.实现了设计过程的信息化和设计结果的数字化,为今后其他大型、复杂装置的多零件系统产品数字化提供了一个很好的范例.     

Down-scattered neutron imaging detector for areal density measurement of inertial confinement fusion

A custom developed (6)Li glass scintillator (APLF80+3Pr) for down-scattered neutron diagnostics in inertial confinement fusion experiments is presented. (6)Li provides an enhanced sensitivity for down-scattered neutrons in DD fusion and its experimentally observed 5-6 ns response time fulfills the requirement for down-scattered neutron detectors. A time-of-flight detector operating in the current mode using the APLF80+3Pr was designed and its feasibility observing down-scattered neutrons was demonstrated. Furthermore, a prototype design for a down-scattered neutron imaging detector was also demonstrated. This material promises viability as a future down-scattered neutron detector for the National Ignition Facility.     

A neutron semiconductor detector based on TIInSe<Subscript>2</Subscript>

A new semiconductor detector of neutron radiation based on a TIInSe₂ crystal has been investigated. The detector is produced from a homogeneous semiconductor sample with two electric contacts and operates in an integrating mode. It is shown that, owing to its high sensitivity (～10^?13 A/(neutron cm^?2 s^?1)) and small size (the volume of the sensitive crystal element is ～7 mm³), the detector is capable of monitoring spatial, time, and intensity distributions of γ rays and neutrons in pulse research reactors.     

Effect of suction nozzle modification on the performance and aero-acoustic noise of a vacuum cleaner

The suction nozzle of a vacuum cleaner was modified to enhance the power performance and to reduce the airflow-induced acoustic noise. The suction power efficiencies of the vacuum cleaner were measured for various nozzles: (1) original nozzle, (2) original nozzle with modified trench height, (3) original nozzle with modified connecting chamber, and (4) a combination of (2) and (3). In addition, the suction pressure and sound pressure level around the suction nozzle were measured to validate the reduction of acoustic noise. The power efficiency and mean suction pressure increased when the trench height of the suction nozzle was increased. This was attributed to the suppression of the flow separation in the suction channel. Modification of the connecting chamber in the original nozzle, which had an abrupt contraction from a rectangular chamber into a circular pipe, into a smooth converging contraction substantially improved the suction flow into the connecting pipe. When both modifications were applied simultaneously, the resulting suction nozzle was more effective from the viewpoints of aerodynamic power increase and sound pressure level reduction.     

Effect of detector masses on calibration of Coriolis flowmeters

Detectors are included in the analysis of Coriolis mass flowmeters with straiht vibrating pipe segments. The effect of the detector masses is worked out on the one hand by perturbation methods supported by computer algebra and on the other by the finite element method. The predictions of both methods agree almost perfectly. They show that care has to be taken in choosing the position of the detectors, because this position may have strong implications for the accuracy to which the calibration of the instrument remains independent of the fluid density.     

A gas mixture regeneration system for a position-sensitive thermal neutron detector with a 3He-based gas converter

A gas mixture regeneration system is designed for a two-dimensional position-sensitive thermal neutron detector based on a multiwire proportional chamber with a ³He-based converter. The basic characteristics of the system are given, and processing steps aimed at decreasing the gas liberation from the detector structure are described. The influence of the electronegative impurity accumulation on the detector characteristics and operation of the gas regeneration system are studied. The system is designed on request of the Laboratory of Neutron Physics, JINR (Dubna), for modernizing the ДH-2 diffractometer operating on beams of the ИБP-2 reactor.     

Apparatus for in situ creep testing during irradiation with high-energy neutrons from a planar neutron source

An apparatus is described for investigating the in situ creep behavior of materials during irradiation with neutrons having a spectrum similar to that of a fusion power reactor. Techniques are discussed for remote, high-vacuum creep testing during irradiation with high-energy neutrons from a planar Be(d,n) source used on the 1.93-m Isochronous Cyclotron at the University of California at Davis. Significant effects of radiation damage on the creep of niobium at a flux of 2 x 10(16) n.m(-2) s(-1) are reported.