Characterization of an Al-STJ-based X-ray detector with monochromatized synchrotron radiation

The characterization of an Al-STJ-based detector with Pb absorber was performed with monochromatized synchrotron radiation. Detector response was measured in the energy range from 3 to 10 keV. A small non-linearity of the signal pulse height was detected, probably due to the escape of recombination phonons from the detector. The non-linearity can be described by a second order polynomial function. Additionally, detector signals were recorded while an X-ray beam of 50 μm diameter was directed to several locations on and near the absorber. For a well-aligned beam, detector artefacts are of at least two orders of magnitude lower intensity than the absorber events.     

Superconducting Tunnel Junction Photon Detectors: Theory and Applications

Superconducting tunnel junctions (STJs) are being developed for photon and particle detection because they combine the high energy resolution of low temperature detector technologies with the high count rate capabilities of athermal devices. This makes them attractive sensors for applications in optical astronomy, synchrotron-based material science and biophysics, and plasma diagnostics. This review provides an overview about STJ design, operation and performance, and discusses some of the scientific applications that are currently driving STJ development.      

STJ X-ray detectors with titanium sublayer

Superconducting tunnel junctions (STJs) with the structure Ti/Nb/Al, AlO_x/Al/Nb/NbN and corresponding layer thickness 30/100/8/13/150/30 nm were investigated as X-ray detectors at T=1.35 K. STJs with one active electrode in which the response of the other one is suppressed due to trapping layer on the surface opposite to the tunnel barrier have a number of potential advantages. The best line width (FWHM) is 78 eV for 6400 μm² junction. Contribution of the electronic noise is about 50 eV. The intrinsic detector line width is less than 60 eV. The collected charge from inactive electrode is more than 8 times less than that from the active one. Titanium proved to be an appropriate material for a sublayer and a trap.     

Direct Position Resolution Measurement with DROIDs at Optical Wavelengths

The DROID (Distributed Read-Out Imaging Detector) is being developed to overcome the limitation in sensitive area with the use of single STJ’s (Superconducting Tunnel Junctions). The DROID configuration allows the reconstruction of the position of the photon absorption and therefore it can replace a number of single STJ’s in a detector array. The position resolution dictates how many STJ the DROID can replace. We present direct measurements of the position resolution in DROIDs, using a 10 μm spot of visible light which illuminates the DROID locally and which is scanned along the absorber length. The DROIDs used for the measurements have 100 nm thick Ta absorber strips with Ta/Al/AlO _x /Al/Ta STJ’s on either end. The STJ’s are square with the same size as the absorber width and the base Ta layer are adjacent to the absorber. The position resolution is measured for absorber length ranging from 200 to 400 μm and 30 μm width.      

Determination of the Photon Impact Position within a DROID

Distributed read-out imaging detectors (DROIDs) combine a good energy resolution with a high position resolving power. Therefore they are promising candidates to build cameras with a huge detection area. A new method is proposed to determine the photon energy and impact position from the two signals of a one-dimensional DROID. For this purpose the diffusion equation was solved for asymmetric devices with arbitrarily trapping. The new method is then applied to fit the experimental data obtained from the illumination with soft X-ray of a 400 μm long Ta absorber strip with one Ta/Al read-out STJ at each end.      

气流粉碎机的现状及技术进展

结合作者的实际工作经验，以及所接触的本行业的国内外先进技术，概述了当今粉体工业上使用的一些气流粉碎设备，阐述了当前国内外气流粉碎机的技术进展情况。     

基于CH375A的CAN-USB总线通信模块设计

针对CAN总线现场数据采集时必须有PC机参与和CAN总线与PC机通讯速率低的问题,提出了此CAN-USB通信模块设计方案;该方案基于USB主/从控制芯片CH375A,在单片机的控制下,既可以实现CAN总线数据采集系统中嵌入USB主机,从而完成把各节点采集的数据存入U盘,取代了现场数据采集系统必须有一台PC机的模式;也可以通过USB设备接口将CAN总线数据转送到PC机进行分析处理并把PC机的数据或命令传送给指定的CAN节点,高效完成PC机与现场设备的通讯.