RIBLL终端LASCAR闪烁体阵列探测器研制进展

介绍了RIBLL终端LASCAR闪烁体阵列探测器的工作原理和结构特点. 描述了为满足放射性核束实验的要求而对阵列所作的重要改进. 给出了LASCAR构型优化改造的工作设想和实施步骤. The principles and structure characteristics of LASCAR scintillator array detector at RIBLL terminal are described. Special emphases are laid upon the latest progress for the development of LASCAR array detector to meet the requirements of the RIB experiments. The working plan and steps for optimizing configuration of the LASCAR multi unit neutron scintillator array detector are also presented.     

用于高能轻粒子探测的延迟线PPAC(英文)

气体探测器有成本低廉、制备简单、性能可靠和方便使用等特点。研制了一种5层板结构的延迟线平行板雪崩电离室（PPAC）,用于兰州放射性束流线（RIBLL）上开展的实验。在57.6 MeV/u的6He束流条件下测试了这种探测器对高能轻粒子的适用性,得到了位置分辨为1.8 mm (FWHM), 时间分辨为2.6 ns, 以及可靠的探测效率。The gas detectors have the characteristics of low cost, easy preparation, reliable capability and convenient for use etc. A delay line parallel plate avalanche counter(PPAC) with five plates has been developed for the experiments at Radioactive Ion Beam Line in Lanzhou(RIBLL). The applicability of counter for high energy light ion has been tested with 57.6 MeV/u 6He beam. A position resolution of ~1.8 mm(FWHM) and a timing resolution of ~2.6 ns are achieved. The detection efficiency is reasonable.     

基于LC延迟电路的双层多丝正比室的研制

描述了为兰州放射性粒子束流线（RIBLL Ⅱ）上测量束流径迹而研制的一种基于LC延迟电路的双层多丝正比室（MWPC）。该探测器的探测灵敏面积为100 mm×80 mm,位置信号由阴极丝引出并通过LC延迟电路读出。探测器由两套完整的多丝正比室组成,每套的阳极丝夹在两层平行的阴极丝之间,阳极丝和阴极丝相互垂直。两套阴极丝相互垂直给出入射粒子的二维位置信息。为了增大感应信号以提高探测效率,将每套位置对应的阴极丝合并成一路接入LC延迟电路。用55Fe-5.9 keV X射线源均匀照射探测器的灵敏区域,测试表明其具有良好的位置灵敏一致性。用X射线源通过准直狭缝扫描整个探测器的灵敏区域,得到X,Y层的位置线性度均好于0.999;其位置分辨（σ）分别为199.9 μm和154.0 μm,目前,该探测器已成功用于RIBLL Ⅱ的实验中。A double-layer Multi-Wire Proportional Chamber (MWPC) with 100 mm×80 mm active area has been developed for Radioactive Ion Beam Line in Lanzhou(RIBLL Ⅱ). The position information has been obtained by a LC delay circuit readout method. Being called of double-layer MWPC, it is composed of two full MWPCs, each consists of an anode plane sandwiched between two parallel cathode planes, anode wires and cathode wires are perpendicular to each other. In order to improve the detection efficiency, the cathode wires of corresponding position are combined to enhance inductive signal. The cathode wires of two full MWPCs are orthogonally placed to give two coordinates of the incident particles. The sensitivity uniformity is also found to be relatively good and the position resolution of X, Y direction are measured to be 199.9 and 154.0 μm using a 55Fe-5.9 keV X ray, respectively. The position linearity of X, Y direction are as good as 0.999 for whole sensitive area of the detector. The detector has been used successfully on the experiment at RIBLL Ⅱ.     

CsI（Tl）+Si-APD探测器的性能测试

介绍了Si-APD的工作原理并对Si-APD中的暗电流进行了理论分析。基于RIBLL上产生的放射性核束流,使用CsI（Tl）+Si-APD探测器对中能重离子进行了能量测试。测试结果显示,CsI（Tl）+Si-APD探测器测量20 MeV/u的重离子时,可得到3%的能量分辨;同时还发现Si-APD中的暗电流大小以及入射粒子的能量大小都会对探测器的能量分辨产生影响。In this paper, the working principle of Si-APD was introduced and the dark current of Si-APD was analyzed theoretically. The intermediate energy heavy ions, which are produced on the RIBLL(Radioactive Ion Beam Line in Lanzhou), were measured with CsI(Tl)+Si-APD detector. The energy resolution of CsI(Tl)+Si-APD detector is about 3% for heavy ions with energy around 20 MeV/u. It is also found that the energy resolution of detector can be in uenced by the dark current of Si-APD and the energy of incident particles.     

MICROMEGAS探测器初步测试

介绍了一种利用鱼线做放大区间隔的MICROMEGAS探测器, 灵敏面积为50 mm ×50 mm。 在Ar+CO₂（10%）气体条件下, 利用55Fe源5.9 keV的 X射线对MICROMEGAS探测器进行了初步测试: 计数率大于103 Hz的条件下, 计数率坪长达到280 V; 当栅极电压在800 V时能量分辨为30%; 当增益高于104时打火率低于10-4; PCB板读出条周期为400 μm条件下的位置分辨好于120 μm。 结果表明, 研制的MICROMEGAS探测器达到了初步设计的基本要求。 In this paper,A MICROMEGAS(Micro Mesh Gaseous Structure) detector with the amplification gap defined by stretching nylon fishing lines has been described . And its count plateau, gas gain and energy resolution in the condition of a 55Fe X ray source and Ar CO₂ (10%) mixture gases are measured as functions of mesh voltage. The count plateau approaches 280 V at the count rate of 103 Hz. The discharge rate is less than 10－4 when the gas gain is up to 104. The energy resolution is 30% (FWHM) based on －800 V mesh voltage. The position resolution is less than 120 μm at the condition of the sensitive area (50 mm×50 mm) Printed Circuit Boards (PCB) and its strip pitch of 400 μm. The results can satisfy the basic demand of MICROMEGAS detector preliminary design.     

Design of Multi-unit Control System of High Voltage Power Supply for LASCAR Scintillator Detector Array

The power voltages of Photomultipliers (PMTs) at RIBLL LASCAR scintillator detector array are distributed between 900 V and 1 800 V irregularly. 392 CC123 modules are employed to supply high voltage for the PMT array. The CC123 module serves as PMT interface groupware package, and it can transform 12 V DC input voltage to ranges of 0～-2200 V for the PMT power supply corresponding to 0～ 5 V output voltage from the control board crate. The relation of PMT power supply with the output voltage of the control crate is shown in Fig.1.     

Temperature Dependence of Electrical Characteristics in Indium-Zinc-Oxide Thin Film Transistors from 10 K to 400 K

The transfer characteristics of amorphous indium-zinc-oxide thin film transistors are measured in the temperature range of 10–400 K. The variation of electrical parameters(threshold voltage, field effect mobility, sub-threshold swing, and leakage current) with decreasing temperature are then extracted and analyzed. Moreover, the dominated carrier transport mechanisms at different temperature regions are investigated. The experimental data show that the carrier transport mechanism may change from trap-limited conduction to variable range hopping conduction at lower temperature. Moreover, the field effect mobilities are also extracted and simulated at various temperatures.     

A new aluminum iron oxide Schottky photodiode designed via sol–gel coating method

A novel aluminum iron oxide(Al/AlFe2O4/p-Si) Schottky photodiode was successfully fabricated via the sol–gel coating process. The microstructure of the spinel ferrite(AlFe2O4) was examined by atomic force microscopy. The current–voltage characteristics of the fabricated photodiode were studied under dark and different illumination conditions at room temperature. By using the thermionic emission theory, the forward bias I–V characteristics of the photodiode are analyzed to determine the main electrical parameters such as the ideality factor(n) and barrier height(ΦB0) of the photodiode. The values of n and ΦB0 for all conditions are found to be about 7.00 and 0.76 eV, respectively. In addition,the values of series resistance(Rs) are determined using Cheung's method and Ohm's law. The values of Rs and shunt resistance(Rsh) are decreased with the increase of illumination intensity. These new spinel ferrites will open a new avenue to other spinel structure materials for optoelectronic devices in the near future.     

Study on the dynamic characteristics of flow over building cluster at high Reynolds number by large eddy simulation

In this paper,the dynamic characteristics of building clusters are simulated by large eddy simulation at high Reynolds number for both homogeneous and heterogeneous building clusters.To save the computational cost a channel-like flow model is applied to the urban canopy with free slip condition at the upper boundary.The results show that the domain height is an important parameter for correct evaluation of the dynamic characteristics.The domain height must be greater than 8h(h is the average building height)in order to obtain correct roughness height while displacement height and roughness sublayer are less sensitive to the domain height.The Reynolds number effects on the dynamic characteristics and flow patterns are investigated.The turbulence intensity is stronger inside building cluster at high Reynolds number while turbulence intensity is almost unchanged with Reynolds number above the building cluster.Roughness height increases monotonously with Reynolds number by 20%from Re*=103 to Re*=105 but displacement height is almost unchanged.Within the canopy layer of heterogeneous building clusters,flow structures vary between buildings and turbulence is more active at high Reynolds number.     

The acoustic characteristics of clause, sentence and paragraph boundaries in Chinese Putonghua

The acoustic and perceptive characteristics of discourse units, including clauses, simple sentences, compound sentences and paragraphs, were studied. The acoustic characteristics were based on the analysis of a speech corpus consisted of ten monologues. The Perceived Boundary Strength (PBS) of the monologues was labeled on a five-point scale by 25 participants. The main results are as follows: (1) There is a significant difference in the PBS of clauses (corresponding to intonational phrase), sentences (including simple sentences and compound sentences) and paragraphs. But the PBS of simple sentences and compound sentences is the same, and the pitch reset and pause are also not significantly different between these two kinds of boundaries. (2) The pitch-based cue used to distinguish clauses, sentences and paragraphs appears to be the difference between pre- and post-boundary syllables, but not simply the pitch value of either syllable alone. (3) Declination mainly occurs within intonational phrases, whereas there is no consistent global declination in sentences or in paragraphs. (4) Pauses are longer and more varied at the boundary of larger discourse units. Moreover, there is a significant positive correlation between pause duration and degree of pitch reset at clause boundaries, but not at sentence or paragraph boundaries.     

二维位置灵敏硅探测器的应用研究

对二维位置灵敏硅探测器进行了239Puα源刻度测试,并在弹性散射实验中使用了二维位置灵敏硅探测器.考察了两种定位方法在实验中与测试中的一致性.测量了二维位置灵敏硅探测器的能量分辨率、位置分辨率和位置畸变.对位置畸变进行了定性理论解释.     

A pilot experiment for mass measurement at CSRe

A pilot experiment of mass measurement was performed at CSRe with the method of isochronous mass spectrometry. The secondary fragments produced via RIBLL2 with the primary beam of 400 MeV/u 36Ar delivered by CSRm were injected into CSRe. The revolution periods of the stored ions, which depend on the mass-to-charge ratios of the stored ions, were measured with a time-of-flight detector system. The results show that the mass resolution around 8×10-6 for Δm/m is achieved.     

一种多阳极横向场电离室

描述了一种将用于兰州放射性束流线较重离子鉴别的多阳极横向场电离室.对其性能进行了初步测试,得到该电离室有较长的坪区和较好的能量分辨.在10⁴Pa的P10工作气体(10%CH₄+90%Ar)下,坪区长度为700V.对²⁴⁴Cm α放射源,在第4片阳极对应的灵敏区域能量损失为1.30MeV,能量分辨41.1keV,相对能量分辨约3.16%。     

RIBLL束流诊断

描述了兰州放射性离子次级束流线(RIBLL)上研制并安装使用的放射性束流(RIB)诊断装置的种类、结构、性能及在AIBLL上的位置和功能.重点叙述了以光纤为基础的几种诊断元件,它们探测效率高、响应时间快、制作容易、性能稳定.给出了RIB¹⁷N等高图,说明诊断装置辅助MBLL得到RIB的水平.     

兰州放射性束流线

兰州放射性束流线（RIBLL）是产生中能重离子放射性束流（RIB）的装置和高精度放射性束物理的实验谱仪．RIBLL的立体角接收度＞65msr、动量接收度达10％;RIBLL可提供极化RIB;RIBLL采用大接收度双消色差反对称结构,既可纯化放射性束,还可作为0°磁谱仪． Radioactive Ion Beam Line in Lanzhou (RIBLL) is a facility to produce intermediate energy radioactive ion beams (RIB), and also a high precision spectrometer for RIB physical experiments. The solid angle acceptance of RIBLL is 6. 5 msr. The momentum acceptance is about 10%. The polarized RIBs will be available. RIBLL is the equipment with double achromatic and asymmetric structure. So that it can not only sublimate the RIBs in pureness, but also operate as 0° magnet spectrometer.     

RIBLL的状态及开展的部分实验研究

简要介绍了兰州放射性束流装置建成一年多来所开展的实验工作和现状, 并对取得的实验结果进行了讨论与分析.The status of RIBLL and some new experiments performed since the first operation of RIBLL in 1997 are described. Some of the experimental results are introduced and discussed.