质子滴线核17Ne在Si靶上反应总截面的测量

描述了在兰州放射性次级束流线上用80MeV/u的2?0?Ne轰击Be靶产生出理论上预言有奇异结构的17Ne的次级束流,并用它轰击Si靶,测量它的反应总截面并与其相邻的核相比较,发现截面值没有增大的现象.利用微观的Glauber模型进行了计算,理论计算和实验结果符合很好,确认其没有奇异结构.     

放射性核束引起反应中轻带电粒子发射的同位旋效应

研究了69MeV/u³⁶Ar轰击Be靶的碎裂产物与Si靶反应引起的前角区轻带电粒子的发射产额与原子核同位旋、原子核序数的关系.发现前角区轻带电粒子发射产额对于丰质子核的结构非常敏感,与同位旋存在一种指数关系.因此可以把前角区轻带电粒子发射产额作为探测丰质子核结构的一种手段,也是一种新的验证一个核是否具有质子晕结构的实验证据.     

不同工作气体对PPAC性能的影响

描述了为RIBLL研制的一种双维位置灵敏PPAC在不同工作气体下的性能测试.位置读出采用电荷分除法.在7mb气压和C₃F₈工作气体时阳极在+595V,对于3组分α粒子,位置分辨为0.64mm.使用异丁烷气体,阳极在+500V,位置分辨为0.76mm.PPAC在两种气体中探测效率均为99.1%.C₃F₈气体质量厚度和能量损失较大,信号幅度较高,适合探测较高能量较轻粒子.异丁烷气体能损较小,适合探测较重粒子.     

HIRFL-CSR commissioning in 2006 and 2007

HIRFL-CSR, a new heavy ion cooler-storage-ring system at IMP, had been in commissioning since the beginning of 2006. In the two years of 2006 and 2007 the CSR commissioning was finished, including the stripping injection (STI), electron-cooling with hollow electron beam, C-beam stacking with the combination of STI and e-cooling, the wide energy-range synchrotron ramping from 7 MeV/u to 1000 MeV/u by changing the RF harmonic-number at mid-energy, the multiple multi-turn injection (MMI), the beam accumulation with MMI and e-cooling for heavy-ion beams of Ar, Kr and Xe, the fast extraction from CSRm and single-turn injection to CSRe, beam stacking in CSRe and the RIBs mass-spectrometer test with the isochronous mode in CSRe by using the time-of-flight method.     

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.     

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 △m/m is achieved.     

Quasi-Elastic Scattering of 16C from 12C at 47.5 MeV/Nucleon

Differential cross sections for the quasi-elastic scattering of^16 C at 47.5 MeV/nucleon from ^12 C target are measured.Coupled-channels calculations are carried out and the optical potential parameters are obtained by fitting the experimental angular distribution.     

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%.     

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. 关键词： Micromegas探测器 计数曲线 能量分辨率 增益