Investigation of two-proton emission from excited states of the odd-Z nucleus P-28 by complete-kinematics measurements

An experiment to study exotic two-proton emission from excited levels of the odd-Z nucleus P-28 was performed at the National Laboratory of Heavy Ion Research-Radioactive Ion Beam Line (HIRFL-RIBLL) facility. The projectile P-28 at the energy of 46.5 MeV/u was bombarding a Au-197 target to populate the excited states via Coulomb excitation. Complete-kinematics measurements were realized by the array of silicon strip detectors and the CsI + PIN telescope. Two-proton events were selected and the relativistic-kinematics reconstruction was carried out. The spectrum of relative momentum and opening angle between two protons was deduced from Monte Carlo simulations. Experimental results show that two-proton emission from P-28 excited states less than 17.0 MeV is mainly two-body sequential emission or three-body simultaneous decay in phase space. The present simulations cannot distinguish these two decay modes. No obvious diproton emission was found.

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。

八单元一维位置灵敏雪崩室

In the experiment of nuclear reaction, it is important to measure the mass, charge, energy and emitted direction of particles. For multiparameter measurement, we must use a detector or a group of detectors which can give the time, energy, and position information. The Large Area position sensitive Ionization Chamber(LAIC) is one of the eight experiment terminals of HIRFL. It is built for researching nuclear reactions from low energy to intermediate energy. It is an excellent equipment for energy measurements and atomic number identification of emitted fragments in this energy region. It is also designed to give the time and position information of the emitted fragments by itself. Obviously, an IC can not supply a good timing signal. Moreover, the mechanical installation is different from the original design by some other reasons. In this case, it is not enough to obtain the correct direction information of the emitted fragments. To obtain good timing signals and the correct direction information, some modifications must be made. It is well known that a PPAC can give us excellent timing signals. It also can be easily built as a position sensitive detector. For this reason, a specially designed PPAC is installed in the entrance of the LAIC. For the different purposes, two types of PPACs were designed and tested. Both are OCTPSACs (OCTunit one dimension Position Sensitive Avalanche Counter). In this paper, both OCTPSACs will be introduced. Based on the requirements of the LAIC, the OCTPSACs consist of eight position sensitive PPACs. Each PPAC has an anode and a cathode. In both cases, the sizes are same. But different type of cathodes are used. In one type of OCTPSAC, its cathode is made of wire plane. It consists of gold-plated tungsten wires with the diameter of 20μm, spaced 0.5 mm apart from each other. The anode is a mylar foil which was evaporated by gold layer with the thickness of 50μg/cm~2 mounted on a printed plate in the shape of rectangle. the thickness of mylar foil is 1.5μm. The gap between anode and cathode is 3mm. The performance of the OCTPSAC has been tested by using a ~(252)Cf source in flowing isobutylene gas at the pressure of 3.4mb. The intrinsic time resolution of 289ps and position resolution of 2 mm have been obtained. In another type of OCTPSAC, the cathode is made of mylar foil, which is composed of gold strip by vacuume evaporation method with a special mask on the mylar foil. The thickness and the width of the gold strip is 50μg/cm~2 and 1.7mm. The strips are spaced 0.3 mm apart from each other. The anode is the same as the former type. We have obtained the time resolution of 296ps and position resolution of 2mm by using ~(241)Am-a source when the gas pressure is 6 mb and high voltage is 600V. The working gas is heptane

25MeV/A~(40)Ar+~(115)In反应中轻粒子发射研究及大面积位置灵敏闪烁探测器的研制

论文分为两个部分。第一部分：研究在25MeV/u ~(40)Ar+~(115)In反应中轻粒子发射机制。实验中，利用研制的轻粒子探测器测量了发射的P、#alpha#能谱。用三源模型拟合了轻粒子能谱，所提取的参数与费米气体模型的计算结果进行比较，分析了发射源形成和衰变的一些特点。第二部分：研制一种大面积幅度、时间、位置灵敏闪烁探测器。它是HIRFL上建成的第一阶段放射性核束物理实验终端的主要设备之一，在首次放射性核束调试中收到良好的效果。本文的目的是用经典理论研究了热核形成及衰变的一些性质，在即将开展的放射性核束物理研究中， 利用研制的大型探测器对经典理论普适性进行检验

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。

Self-assembled 3D Architectures of LuBO3 : Eu3+: Phase-selective synthesis, growth mechanism, and tunable luminescent properties

Rhombohedral-calcite and hexagonal-vaterite types of LuBO:Eu3+ microparticles with various complex self-assembled 3D architectures have been prepared selectively by an efficient surfactant- and template-free hydrothermal process for the first time. X-ray diffraction, scanning electron microscopy, energy-dispersive X-ray spectrometry, transmission electron microscopy, high-resolution transmission electron microscopy, selected area electron diffraction, photoluminescence, and cathodoluminescence spectra as well as kinetic decays were used to characterize the samples.

Synthesis and luminescent properties of Lu3Ga5O12 : RE3+ (RE = Eu, Tb, and Pr) nanocrystalline phosphors via sol-gel process

Lu3Ga5O12:Eu3+, Lu3Ga5O12:Tb3+, and Lu3Ga5O12:Pr3+ phosphors were prepared through a Pechini-type sol-gel process. X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), photoluminescence, and cathodoluminescence spectra were utilized to characterize the synthesized phosphors. The XRD results reveal that the sample begins to crystallize at 800 degrees C and fully crystallined pure Lu3Ga5O12 phase can be obtained at 1000 degrees C. The FESEM image indicates that the phosphor sample is composed of aggregated rice grainlike particles with sizes around 80-120 nm.

Hydrothermal synthesis and luminescent properties of LuBO3: Tb3+ microflowers

Hexagonal vaterite-type LuBO3:Tb3+ microflower-like phosphors have been successfully prepared by an efficient surfactant- and template-free hydrothermal process directly without further sintering treatment. X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), energy-dispersive X-ray (EDX) spectrometry transmission electron microscopy (TEM), high-resolution transmission electron microscopy (HRTEM), selected area electron diffraction (SAED), photoluminescence(PL) and cathodoluminescence (CL) spectra as well as kinetic decays were used to characterize the samples.

Thermoluminescence characteristics of rare-earth-doped LiCaBO3 phosphor

LiCaBO3 was synthesized by high-temperature solid-state reaction. The influence of different rare earth dopants, i.e. Dy3+, Tb3+. TM3+ and Ce3+, on thermoluminescence (TL) of LiCaBO3 phosphor was discussed. We studied the TL properties and some dosimetric characteristics of Ce3+-activated LiCaBO3 phosphor in detail. The effect of the concentration of Ce3+ on TL was investigated, the result of which showed that the optimum Ce3+ concentration was 1 mol%. The TL kinetic parameters of LiCaBO3:0.01 Ce3+ were studied by computer glow curve deconvolution (CGCD) method.

Amphiphilic Core-Shell Nanocarriers Based On Hyperbranched Poly(ester amide)-star-PCL: Synthesis, Characterization, and Potential as Efficient Phase Transfer Agent

Amphiphilic biodegradable star-shaped polymer was conveniently prepared by the Sn(Oct)(2)-catalyzed ring opening polymerization of c-caprolactone (CL) with hyperbranched poly(ester amide) (PEA) as a macroinitiator. Various monomer/initiator ratios were employed to vary the length of the PCL arms. H-1 NMR and FTIR characterizations showed the successful synthesis of star polymer with high initiation efficiency. SEC analysis using triple detectors, RI, light scattering, and viscosity confirmed the controlled manner of polymerization and the star architecture.

Thermoluminescence characteristics of NaSr4(BO3)(3):Ce3+ under beta-ray irradiation

The thermoluminescence (TL) properties of Ce3+ doped NaSr4(BO3)(3) phosphor under the beta-ray irradiation were reported. The polycrystalline sample was synthesized by high temperature solid-state reaction. The TL glow curve of NaSr4(BO3)(3):Ce3+ phosphor was composed of only one peak. TL kinetic parameters of NaSr4(BO3)(3):Ce3+ were deduced by the peak shape method, the activation energy (E) was 0.590 eV and the frequency factor was 1.008x10(6) s(-1). TL dose response was linear in the range of measurement. The 3-dimensional (3D) TL emission spectrum was also recorded, the emission spectrum consisted of two bands located at 441 and 479 nm respectively, corresponding to the characteristic 4f(0)5d(1)-> F-2((5/2,7/2)) transitions of the Ce3+ ion. The fading behavior of the NaSr4(BO3)(3):Ce3+ phosphor over a period of 15 d was also studied.

Morphological control and luminescent properties of CeF3 nanocrystals

The nanocrystals of CeF3 with the hexagonal structure and different morphologies such as the disk, the rod, and the dot have been successfully synthesized via a mild ultrasound assisted route from an aqueous solution of cerium nitrate and different fluorine sources (KBF4, NaF, NH4F). The use of different fluorine sources has a remarkable effect on the morphology of the final product. The luminescence and UV-vis absorption properties of CeF3 nanocrystals with different morphologies have been investigated. Compared with other shape nanocrystals, the luminescence intensity of the disklike nanocrystals is obviously enhanced. It is suggested that the function-improved materials could be obtained by tailoring the shape of the CeF3 nanocrystals.