Micromegas探测器计数曲线、增益以及能量分辨特性的研究

介绍了自行研制的Micromegas探测器的基本结构和工作原理. 在不同工作气体(Ar和CO2)配比条件下，利用55Fe放射源对该探测器的能量分辨、计数曲线和气体增益等特性进行了较为详尽的测试. 对相关结果进行了讨论.

beta-delayed fission of Ac-228

The basic process of an exotic decay mode namely P-delayed fission is simply introduced. The progress status of the study in the world is essentialized. The observation of P-delayed fission of Ac-228 is reported. The radium was radiochemically separated from natural thorium. Thin Ra sources in which Ac-228 was got through Ra-228 ->(beta-) Ac-228 were prepared for observing fission fragments from beta-delayed fission Ac-228. They exposed to the mica fission track detectors, and measured by an HPGe gamma-ray detector. The beta-delayed fission events of Ac-228 were observed and its beta-delayed fission probability was found to be (5 +/- 2) x 10(-12).

Surface morphology of He-implanted single-crystalline silicon

Single-crystalline Si (100) samples were implanted with 30 keV He2+ ions to doses ranging from 2.0x10(16) to 2.0x10(17) ions/cm(2) and subsequently thermally annealed at 800 degrees C for 30min. The morphological change of the samples with the increase of implantation dose was investigated using atomic force microscopy (AFM). It was found that oblate-shaped blisters with an average height around 4.0nm were found on the 2.0 x 10(16) ions /cm(2) implanted sample surface; spherical-shaped blisters with an average height wound 10.0nm were found on the 5.0 x 10(16) ions/cm(2) implanted sample surface; strip-shaped and conical cracks were observed on the sample He-implanted to a dose of 1.0 X 10(17) ions /cm(2). Exfoliations occurred on the sample surface to a dose of 2.0 x10(17) ions /cm(2). Mechanisms underlying the surface change were discussed.

Hadron physics programs at HIRFL-CSRm: Plan and status

An internal target experiment at HIRFL-CSRm is planned for hadron physics, which focuses on hadron spectroscopy, polarized strangeness production and medium effect. A conceptual design of Hadron Physics Lanzhou Spectrometer (HPLUS) is discussed. Related computing framework involves event generation, simulation, reconstruction and final analysis. The R&D works on internal target facilities and sub-detectors are presented briefly.

A proposal design of a multi-hit two-dimensional position-sensitive energy spectrum detector

A new non-linear comparison method of charge-division readout scheme is conceived and the first design of a multi-hit two-dimensional position-sensitive energy spectrum Si(Au) surface barrier detector with a continuous sensitive area is proposed.

Search for beta-delayed fission of Ac-228

Radium was radiochemically separated from natural thorium. Thin Ra-228 ->beta Ac-228 sources were prepared and exposed to mica fission track detectors, and measured by an HPGe gamma-ray detector. The beta-delayed fission events of Ac-228 were observed and its beta-delayed fission probability was found to be (5 +/- 2)x10(-12).

Design and simulation of charge sensitive preamplifier with CMOS FET implemented as feedback capacitor C-fp

In this paper, to design a new preamplifier for optimum performances with charged-particle or heavy-ion detectors, the CMOS FET is implemented as a feedback capacitor C-fp, so that the entire system should be built only with MOSFET. This work is a revolution design because to realize an ASIC for a preamplifier circuit, the capacitor will also be included. We succeed after a simulation to maintain a rise time less than 3 ns, the output resistance less than 94 Omega and the linearity almost good.

用于粒子探测器的CMOS FET采样保持电路的设计与仿真(英文)；Design and Simulation of Track/Hold Circuit with CMOS FET for Particle Detector

介绍了一个峰保持电路。该电路适用于silicon strip,Si(Li),CdZn Te and CsI等探测器,实现采样-保持功能。已成功进行了基于CMOSFET的采样-保持电路的设计和仿真,通过使用Proteus的PSPICE仿真器和BSIMV3.3模型参数完成了电路性能的仿真。同时,实现了采样时间可在60ns到4.44s范围内进行选择,该电路具有较好的线性。

Development of multi-channel gated integrator and PXI-DAQ system for nuclear detector arrays

A multi-channel gated integrator and PXI based data acquisition system have been developed for nuclear detector arrays with hundreds of detector units. The multi-channel gated integrator can be controlled by a programmable Cl controller. The PXI-DAQ system consists of NI PXI-1033 chassis with several PXI-DAQ cards. The system software has a user-friendly GUI which is written in C language using LabWindows/CVI under Windows XP operating system. The performance of the PXI-DAQ system is very reliable and capable of handling event rate up to 40 kHz. (C) 2010 Elsevier B.V. All rights reserved.

A high performance Time-of-Flight detector applied to isochronous mass measurement at CSRe

A high performance Time-of-Flight detector has been designed and constructed for isochronous mass spectrometry at the experimental Cooler Storage Ring (CSRe) The detector has been successfully used in an experiment to measure the masses of the N approximate to Z approximate to 33 nuclides near the proton drip-line Of particular interest is the mass of As-65 A maximum detection efficiency of 70% and a time resolution of 118 +/- 8 Ps (FWHM) have been achieved in the experiment The dependence of detection efficiency and signal average pulse height (APH) on atomic number Z has been studied The potential of APH for Z identification has been discussed (C) 2010 Elsevier B V All rights reserved

4p探测器的研制及测试

本文主要分为两部分，第一部分是有关兰州多阵列4π探测器的设计，它主要是用于中能核反应的实验研究，因而它是根据中能核反应的特点来设计的，具有大的立体角的覆盖，好的空间分辨，低的能量阈以及较大范围的能量、动量测量和良好的粒子分辨等特点。第二部分主要介绍了此4π探测器的单元探测器的研制，其单元主要是由快塑料闪烁体和CsI(Tl)晶体组成的叠层望远镜及由快塑料与慢塑料闪烁体组成的叠层望远镜，主要包括快塑料闪烁体(BS498x)的研制，碘化铯(铊)晶体的选择，光子在闪烁体和光导中传输效率的模拟计算，光电倍增管Base电路的设计，最后是利用HIRFL加速的~(18)O和~(40)Ar束流轰击Ni靶产生的核反应产物对上述两种单元进行了测试，取得非常好的粒子分辨和轻粒子同位素分辨。

用于RIBLL和CSR的气体探测的研制

气体探测器是历史最悠久的核探测器之一气体探测器具有成本低廉、制备简单、性能可靠和使用方便等特点。而且气体探测器的形状和尺寸可任意设计，厚度可随气体气压的变化而改变，适合做大面积位置灵敏、大立本角探测和有较宽的动态测量范围。所以气体探测器在各自的应用范围内发挥着巨大的作用。在兰州放射性束流线（RIBLL）上开展次级束实验的过程中，束流的定位和发散度测定都是非常重要的。我们研制了两种高性能的双维位置灵勘平行板雪崩计数器（PPAC），一种为传统的三个极板结构，另外一种为五个极板的多极结构，分别适用于较重粒子和轻粒子的位置测量。对于五个极板的多极结构的探测器，灵敏面积为100mm×100mm，采用电荷分除法读出位置，我们用3组分α源测试，工作气体选用异丁烷。测试在6.5mb气压下，位置分辨为0.55mm（FWHM），探测效率大于99.2％，位置离散小于士0.2mm。一系列的性能指标都达到了同类探测器的最好水平。该探测器和以前研制的三极板PPAC的性能均已满足RIBLL的要求，将会用作RIBLL重要的束诊元件和位置探测器。同时改进后还能在即将建成的兰州重离子加速器冷却存储环（HIRFL-CSR）上的束流诊断过程中发挥重要的作用。同时，为在RIBLL上开展超重元素和超重核素的合成实验研制了一种多阳极横向场气体电离室（MAIC）。在100mbP10气体下，对应第四块大灵敏区域，5.806MeV~(244)Cm的α粒子的能量损失为1.30MeV，得出该探测器的能量分辨为41.1keV（FwHM），相对分辨为3.16％。该探测器适合于较重粒子的鉴别，性能指标已经满足RIBLL鉴glI灼子的要求。

空间望远镜系统的设计及硅锂探测器的研制

论文的结构分为空间望远镜系统的设计和硅（锂）探测器研制两个部分。第一部分主要介绍了空间望远镜系统的设计，该空间望远镜系统能鉴别Z≤26、M≤56范围内的空间带电粒子，该系统的设计在国内是首例，它将使我国空间高能带电粒子的鉴别和测量上一个新的台阶；第二个部分主要介绍适合于探测空间粒子的硅（锂）探测器的研制及其性能的测试过程。该探测器的研制成功为空间高能带电粒子的探测提供了必要的准备。 我们已经提供给空间科学与应用研究中心二十多块硅（锂）探测器。我们用ThC'-C源和137Cs源对硅（锂）探测器进行了测试，我们在120V时便可得到137Cs电子谱；我们在250V常温常压得到α粒子谱，其能量分辨可好于37Kev，长期加压测试时硅（锂）探测器的反向电流变化稳定，在持续20天加压250V时，其中直径为12mm的硅（锂）探测器的电流变化可达1.10±0.50微安，信噪比可达420倍。

Essential elements of integrated coastal zone management

The coastal zone comprises a narrow strip of coastal lowlands and a vast area of coastal waters. While the coastal zone represents approximately 10% of the earth's surface, its coastal lowlands are inhabited by more than 50% of the world population. The coastal zone has become the major site for extensive and diverse economic activities. Many of the coastal developing countries depend heavily on the scarce coastal resources for their economic growth.

Effect of polydispersity on the self-assembly structure of diblock copolymers under various confined states: A Monte Carlo study

We studied the self-assembly of polydisperse diblock copolymers under various confined states by Monte Carlo simulation. When the copolymers were confined within two parallel walls, it was found that the ordered strip structures appeared alternately with the increase in wall width. Moreover, the wall width at which the ordered structure appeared tended to increase with an increase in the polydispersity index (PDI). On the other hand, the simulation results showed that the copolymers were likely to form ordered concentric strip structures when they were confined within a circle wall.