Design studies on the 4π γ-ray calorimeter for the ETF experiment at HIRFL-CSR

A high detection efficiency calorimeter which is used to detect γ-rays with energies from 1 MeV up to 10 MeV as well as light charged particles has been proposed. Design of the geometry, results of the crystal tests and Monte Carlo simulations are presented in this paper. The simulation results confirm that the calorimeter can obtain high detection efficiency and good energy resolution with the current designed geometry. And the calorimeter is competent for the future External Target Facility (ETF) experiments.     

基于GEANT4的CsI(T1)闪烁体探测器的Monte Carlo模拟

对闪烁光在晶体内的传输以及光电子倍增过程进行了建模,基于GEANT4软件包对CsI(T1)闪烁体探测器进行了蒙特卡罗模拟,得到了不同形状、尺寸和包装的CsI(T1)晶体测量γ射线的能谱.对比模拟和测试结果,两者得到了很好的符合,从而验证了模拟参数的合理性和可靠性.该模拟程序的建立为闪烁体探测器的设计提供了更精确的开发工具.     

Studies of a scintillator-bar detector for a neutron wall at an external target facility

To achieve a better time resolution of a scintillator-bar detector for a neutron wall at the external target facility of HIRFL-CSR, we have carried out a detailed study of the photomultiplier, the wrapping material and the coupling media. The timing properties of a scintillator-bar detector have been studied in detail with cosmic rays using a high and low level signal coincidence. A time resolution of 80~ps has been achieved in the center of the scintillator-bar detector.     

DAMPE-PSD探测单元模块大动态范围读出方案的实验验证

暗物质粒子探测卫星（Dark Matter Particle Explorer,DAMPE）的塑闪阵列探测器（Plastic Scintillator Detector,PSD）需要实现高能e/γ粒子的鉴别功能以及对Z=1~20的宇宙线重离子的电荷测量功能。它使用光电倍增管作为读出器件,并从打拿极5和打拿极8同时引出信号来增大读出动态范围。基于该设计方案的探测单元模块在兰州重离子加速器冷却储存环（HIRFL-CSR）上的外靶终端（ETF）进行了束流测试实验。实验得到了PSD单元条在中能轻核区（Z≤8）的能量响应,并证明了单元条的衰减长度与入射粒子种类无关。通过将实验结果外推至高能重核区,同时结合衰减长度、入射角度和能量涨落等因素,可以估算出PSD探测单元模块输出信号幅度的动态范围。结果显示,该范围在PSD前端电子学模块的线性工作区间内,从而验证了PSD大动态范围读出方案设计的合理性。The Plastic Scintillator Detector (PSD) of DArk Matter Particle Explorer (DAMPE) aims for high energy e/γ identification and charge measurement for cosmic-ray ions from Z=1~20. It adopts photomultiplier tube as the readout device and extracts signals from both dynode5 and dynode8 to enlarge the readout dynamic range. A beam test on a PSD detector unit based this design has been carried out at the External Target Facility (ETF) terminal of the Cooling Storage Ring of Heavy Ion Research Facility in Lanzhou (HIRFL-CSR). The detector response to light nuclei (Z≤8) at the medium energy scale was extracted and the attenuation length was proved to be irrelevant with the impinging nuclei species. By extrapolating the result to heavy nuclei at the high energy scale and taking into account light attenuation, energy fluctuation and imping angle, the dynamic range of the output signal of PSD detector unit was estimated. The range is well within the linear range of the front-end electronics of PSD, thus verifies the large dynamic range readout design of PSD.     

HIRFL-CSR ETF多层CsI(Tl)望远镜探测器能量刻度方法

在兰州重离子加速器冷却储存环（HIRFL-CSR）的外靶终端（ETF）,设计建造了一套多层CsI（Tl）望远镜探测器,用于对轻质量带电粒子的鉴别。这套探测器由7层CsI（Tl）晶体组成,每一层晶体光输出信号由4个光电倍增管分别在晶体4角读出。由于CsI（Tl）晶体对于重离子的响应是非线性的,且与入射离子的种类有关,这些因素使得对这台探测器的能量刻度需要做专门的研究。利用RIBLL2提供的能量在200 s~300 MeV/u的次级束流对探测器进行了测试,并针对第一片CsI（Tl）晶体的光输出以及所有CsI（Tl）晶体光输出的和的刻度方法分别进行了探索。在此能区下,第一片CsI（Tl）晶体猝灭现象可以近似忽略,即光输出与能量沉积近似呈线性。对于所有晶体光输出的和,利用一个经验公式对其进行刻度,利用这种刻度方法计算得到的光输出的值与实验测量值之间的差别小于5%。A multi-layer CsI(Tl) telescope has been designed and constructed at External Target in Facility (ETF) terminal of the Cooling Storage Ring of Heavy Ion Research Facility in Lanzhou(HIRFL-CSR), and is used for identifying light charged particles. The detector consists of seven layers of CsI(Tl) crystals, and the signals of each crystal are read out by four photomultipliers at the corners. Since the response of the CsI(Tl) crystal to the heavy ions is non-linear and also depends on the species of the incident ions, the energy calibration method of the telescope must be carefully studied. With the help of the secondary beams selected by RIBLL2 in the energy ranges from 200 to 300 MeV/u, the telescope has been tested and the energy calibration method for the first-layer crystal together with the whole telescope has been investigated. In this energy region, the quench effect in the first-layer crystal can be neglected and a linear expression can be used to represent the relation between the light output and the energy deposition in the crystal. To the total light output of the telescope, an empirical formula is used for the energy calibration. The difference between the calculated results and the experiment data is globally less than 5%.     

(S)-4-[(叔丁基二苯基甲硅烷基)氧基]-5-[(4-甲氧基苄基)氧基]戊醛的合成

以L-谷氨酸为起始原料,经重氮化、羧基还原、羟基保护、内酯还原、脱保护基及氧化等7步反应合成了Goniothalalmin类似物的关键中间体——(S)-4-[(叔丁基二苯基甲硅烷基)氧基]-5-[(4-甲氧基苄基)氧基]戊醛(8),总收率12%。8为新化合物,其结构经1H NMR,13C NMR,IR和HR-MS表征。     

Si-Csl（TI）望远镜探测系统用于大动态范围空间重离子鉴别与测量的研究

太阳极轨射电望远镜（SPORT）是一颗从事太阳活动研究的卫星。重离子探测仪是其中的高能粒子探测仪的关键组成部分。鉴于重离子探测仪对多种类离子（2 ≤ Z ≤ 26）的鉴别和大范围能段（8～300 MeV/u）的测量需求,中国科学院近代物理研究所设计并研制了一套Si-CsI（Tl）望远镜探测系统样机,这套望远镜系统由1个Si探测器、1个入射面为正六边形的CsI（Tl）晶体及其专用电子学系统构成。利用兰州重离子加速器冷却储存环系统（HIRFL-CSR）提供的高品质束流对这套望远镜探测系统样机进行了在束测试,完成了种类为2 ≤ Z ≤ 18的重离子直接测量与鉴别,利用直接测量的重离子,进行外推得到,最高测量要求的300MeV/u Fe离子也在设计要求的范围内。实验结果显示这套望远镜探测器样机满足空间中对大范围能段重离子探测的设计需求,该套方案为SPORT计划中的重离子探测仪的设计及建造奠定了很好的技术基础。Solar Polar Orbit Radio Telescope (SPORT) project, aimed at solar activities and solar atmosphere, is a satellite-borne apparatus which is composed by many sub-payloads and is under development in China. High Energy Heavy Ion Telescope (HEHIT) is one of most key sub-payloads in this project, and the main purpose of HEHIT is to identify space heavy ions (2 ≤ Z ≤ 26) with a broad energy range (8～300 MeV/u). In this paper, a prototype telescope of HEHIT, which includes a silicon detector, a CsI(Tl) crystal with regular hexagonal incident plane and customized electronic system, has been developed in the Institute of Modern Physics, Chinese Academy of Sciences (IMP, CAS). To obtain the performance of the prototype telescope, this telescope was tested with high quality beams provided by the accelerator of Heavy Ions Facility and Cooler-Storage-Ring in Lanzhou (HIRFL-CSR). The heavy ions ranging from Z =2 to Z =18 were clearly identified and measured from the beam test and an extrapolation was also done reasonably and it showed that the prototype detector could meet the requirement of t Fe(Z =26) with energy up to 300 MeV/u. In a word, this prototype telescope could satisfy the requirements of the measured heavy ions in the future SPORT project and this scheme of telescope will provide a favorable technique in the future design and construction of HEHIT.     

太阳能海水淡化系统经济性分析与研究

利用单因素分析方法,计算三效塔式太阳能海水淡化系统各个参数对太阳能海水淡化系统淡水生产成本的单因素影响值,分别给出太阳能集热系统成本、储热水箱成本、海水淡化装置成本、装置运行年消耗动力费用、设备使用年限和淡水年生产总量等参数对淡水生产成本影响的程度,明确降低淡水生产成本的方向,有助于太阳能海水淡化装置的深入研究。     

一种基于SiPM的新型起始时间探测器研制

本文介绍了一种新型起始时间探测器的研制。该探测器的灵敏面积为60 mm×60 mm,利用120根直径为1 mm的塑料闪烁光纤分成两层错位紧致排布,且上下相邻的3根光纤作为一个探测单元,每个探测单元均采用硅光电倍增管从双端读出信号。采用90Sr放射源对单根光纤进行了性能测试,结果表明,闪烁光沿着光纤方向的有效传播速度约为17 cm/ns,对应的时间分辨优于600 ps。此外,利用中国科学院近代物理研究所第二条放射性束流线（RIBLL2）提供的240 MeV/u的15N次级束研究了该探测器的性能。束流测试结果表明:该探测器的时间分辨为（150±15）ps,纵向位置分辨为（1.8±0.2）cm,并且结合该探测器以及RIBLL2束流线外靶实验终端上的其他探测器,可以对实验中产生的5 ≤ Z ≤ 8的各种同位素进行非常好的粒子鉴别。     

基于GEANT4的CsI(Tl)闪烁体探测器的Monte Carlo模拟

对闪烁光在晶体内的传输以及光电子倍增过程进行了建模,基于GEANT4软件包对CsI(T1)闪烁体探测器进行了蒙特卡罗模拟, 得到了不同形状、尺寸和包装的CsI(Tl)晶体测量γ射线的能谱。对比模拟和测试结果,两者得到了很好的符合,从而验证了模拟参数的合理性和可靠性。该模拟程序的建立为闪烁体探测器的设计提供了更精确的开发工具。 With the modeling of the light transportation in crystal and electron multiplication in the PMT, a Monte Carlo simulation of CsI(Tl) scintillator detector has been implemented with Geant4 toolkit. The energy spectra simulated with different crystal shape, size and wrappings are obtained. And the reliability of the simulation parameters is confirmed by comparing with the measurements. The simulation code can be used as an reliable tool for the design of scintillator detectors.