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57.6MeV/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1.8mm(FWHM),时间分辨为2.6ns,以及可靠的探测效率。     

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.     

20Mgβ衰变谱学与15O(α,γ)19Ne反应(英文)

15O（α，γ）19Ne（p，γ）20Na反应链是高温CNO循环向快速质子俘获过程突破的一条关键路径，相关的反应率输入量可通过20Mg的β衰变可布居19Ne共振态并测量其衰变性质来获得。通过高效率高精度地测量20Mg β衰变中产生的质子与γ射线得到了20Mg衰变的详细信息，并构建了完整的衰变纲图，还进行了19Ne 4 033 keV共振态衰变性质的探索，获得了该态在20Mg β衰变中被布居的分支比上限。通过比20Mg和20O镜像能级跃迁的结果确认了同位旋非对称性，为检验相关理论模型提供了精确的实验数据。对于突破路径中有重要影响的19Ne 4 033 keV共振态的性质，有待更高统计的实验进一步研究。The breakout from the hot CNO cycle to the rapid proton capture process can occur via the 15O(α,γ)19Ne(p,γ)20Na reaction sequence, and the β decay of 20Mg can be used as an alternative method to characterize some specific resonances, which will provide detailed nuclear structure input for reaction rate calculations. The reliable information on the decay properties and structure of 20Mg was obtained by measuring the emitted particles and γ-rays in the β decay with high efficiency and high resolution. Attempt was also made to search for the decay channels associated with the 4 033 keV resonance in 19Ne. To test fundamental symmetries, the transitions in the mirror decays of 20Mg and 20O were compared. The precise experimental data presented here would be important to constrain the theoretical calculations. It is desirable to clarify the astrophysically relevant problem by further experiments with improved statistics on the basis of the present work.     

反质子与离子研究装置FAIR 介绍

 未来几年, 在德国将会建成一个新的国际科学装置FAIR。FAIR 是一个综合性的粒子加速器系统, 它是反质子与离子研究装置(Facility for Antiproton and IonResearch)的简称。FAIR 建成后, 将能提供任意一种稳定或非稳定化学元素(从氢到铀)离子的高能量和高强度的束流, 且束流具有前所未有的高品质。FAIR 还将提供短寿命原子的次级束流和反质子束流。FAIR 涵盖了很广的与离子相关的科学目标, 建成后它将为全欧洲乃至全世界的科学家开展前沿研究提供优良条件。     

兰州重离子加速器冷却储存环

 兰州重离子加速器冷却储存环HIRFL-CSR，是一个多用途、多功能的双冷却储存环同步加速器系统，由主环CSRm和实验环CSRe构成，并以兰州重离子级联回旋加速器HIRFL作注入器。CSR利用高频变谐波的方法，将重离子束的能量从7～25 MeV/u同步加速到２00～1 000 MeV/u，同时利用重离子储存环中空心电子束冷却技术将束流品质提高１个数量级，并通过储存环的快引出及慢引出，提供多种类的重离子束以及放射性次级束(RIBs)，以开展范围更广精度更高的物理实验。该装置于2007年投入运行，已取得了重要的运行结果，如实现了剥离注入与多圈注入、空心电子束对重离子束的冷却与累积、变谐波宽能区同步加速、等时性环型谱仪、RIBs的产生收集与ToF高分辨质量测量以及高能重离子束的变能慢引出等。     

用于浅层肿瘤重离子治疗的终端束流诊断控制系统

 设计了中国科学院近代物理研究所利用兰州重离子研究装置（HIRFL）进行浅层肿瘤临床治疗试验研究中所使用的束流诊断安全控制系统。该系统包括束流强度监测及保护、剂量测量、扫描波形监测及保护3个部分。系统基于PXI系统及LabVIEW软件，给出了该系统的各部分结构。从系统建立时的多次测试结果以及实际临床治疗试验研究时的长期运行结果来看，该束流诊断控制系统在控制辐照剂量以及安全保护方面能够满足当前重离子加速器浅层肿瘤临床治疗试验的基本要求，为试验研究的顺利进行提供了可靠的保证。     

Configuration of the valence neutrons of ~(17)B

The reaction cross section of ~(17)B on ~(12)C target at(43.7±2.4)MeV/u has been measured at the Radioactive Ion Beam Line in Lanzhou(RIBLL).The root-mean-square matter radius(R_(rms))was deduced to be(2.92±0.10)fm,while the R_(rms)of the core and the valence neutron distribution are 2.28 fm and 5.98 fm respectively.Assuming a"core plus 2n"structure in ~(17)B,the mixed configuration of(2s_(1/2))and(1d_(1/2))of the valence neutrons is studied and the s-wave spectroscopic factor is found to be(80±21)%.     

β-delayed neutron decay of 21N

The β-delayed neutron and γ spectra of neutron-rich nucleus ²¹N using β-γ and β-n coincidence measurements were presented in this paper. Thirteen new neutron groups ranging from 0.28 MeV to 4.98 MeV and with a total branching ratio 88.7±4.2% were observed. One γ transition among the excited states of ²¹O, and four γ transitions among the excited states of ²⁰O were identified in the β decay chain of ²¹N. The ungated half-life of 83.8±2.1 ms was also determined for ²¹N.     

Performance of a double sided silicon strip detector as a transmission detector for heavy ions

The performance of a double sided silicon strip detector （DSSSD）, which is used for the position and energy detection of heavy ions, is reported. The analysis shows that although the incomplete charge collection （ICC） and charge sharing （CS） effects of the DSSSD give rise to a loss of energy resolution, the position information is recorded without ambiguity. Representations of ICC/CS events in the energy spectra are shown and their origins are confirmed by correlation analysis of the spectra from both the junction side and ohmic side of the DSSSD.