Article title: CSHINE for studies of HBT correlation in Heavy Ion Reactions

DOI: 10.1007/s41365-020-00842-2

One sentence summary:

一句话概要：

More detailed isospin studies can be conducted efficiently using the newly developed Compact Spectrometer for Heavy Ion Experiment (CSHINE).

新研发的用于重离子实验的紧凑型谱仪(CSHINE)为同位旋物理的相关研究提供了有效手段

http://www.nst.sinap.ac.cn/newsDetails/112/3088/en/

The Novelty (What)

创新性（主要内容）

As an attempt to facilitate the expansion of the field of nuclear and particle physics, this study constructed a Compact Spectrometer for Heavy Ion Experiment (CSHINE). The CSHINE consists of silicon strip detector (SSD) telescopes and large-area parallel plate avalanche counters (PPAC), which measure the light charged particles and fission fragments,  respectively. When CSHINE was mounted and operated in the 30 MeV/u ⁴⁰Ar + ¹⁹⁷Au reaction, hydrogen and helium isotopes can be identified by analyzing the data obtained from the SSD telescopes. Moreover, the Hanbury Brown−Twiss (HBT) correlation functions of light-charged particles could be constructed from the data retrieved. These results eventually contributed to the measurement of isospin chronology. By utilizing CSHINE, more quantitative studies on the reaction dynamics and thermodynamics of nuclear matter produced in heavy ion collisions can be carried in the future.

紧凑型重离子实验谱仪 (CSHINE) 的研发，旨在为日益发展的核物理和粒子物理研究提供一个新的手段。CSHINE由硅条探测器 (Silicon Strip Detector, SSD)望远镜和大面积平行板雪崩计数器 (Parallel Plate Avalanche Counters, PPAC)所组成，分别用于探测轻带电粒子和裂变碎片。CSHINE安装并运行于30 MeV/u 40Ar + 197Au反应之中，通过分析硅条望远镜获得的数据，实现了氢和氦同位素的粒子鉴别。基于实验数据构建了轻带电粒子的Hanbury Brown−Twiss (HBT)关联函数。这些关联函数可实现对粒子同位旋相关的发射时标测量。不仅如此， CSHINE同时也为重离子碰撞过程中核物质的动力学和热力学性质的研究提供新的机会。

The Background (Why)

研究背景（主要原因）

An isospin is a quantum number to differentiate to neutron and proton. In nuclear physics, isospin dynamics are very important for understanding the effect of nuclear symmetry energy in heavy ion collisions. Hence, it is necessary to investigate the emission time of light-charged particles with different N/Z values (neutron-proton ratio) from the reactions. While the measurement reveals the isospin chronology, it also requires high-resolution determination of both the position and energy to reconstruct the HBT correlation function, which must be done before the isospin-dependent emission time constant can be derived. In order to achieve that, position-sensitive detectors with high granularity, high energy resolution and particle identification, for example, SSDs, are needed. Using the SSD telescopes in CSHINE, the correlation functions of different particle pairs can be measured to extract the emission time constant and emission hierarchy of the species. Based on the output so far, CSHINE showed high potential in facilitating experimental studies of the collision dynamics and nuclear equation of state in heavy ion reactions at Fermi energies.

同位旋是区别中子和质子的量子数，在核物理中，重离子碰撞中的同位旋动力学研究对于理解核物质对称能具有重要意义，从这个角度来讲，对具有不同N/Z值（中子质子比）的轻带电粒子发射时标进行测量变得非常有必要。为了实现通过HBT关联函数方法对同位旋相关的粒子发射时标的测量，需要探测器同时有较高的位置和能量分辨。因此，CSHINE采用了高颗粒度位置灵敏和高能量分辨与粒子识别本领的硅条望远镜，完成不同粒子对的关联函数测量，得到粒子的发射时标和发射次序。已有结果表明，在费米能区重离子反应动力学以及核物质状态方程的实验研究中，CSHINE具有很大的潜力。

The SDG impact (Big Why)

SDG影响力（研究意义）

It is agreeable that both economic and environmental challenges can be overcome with progressive innovation and technologies. To ensure such progression is possible, equipment and tools must be developed and upgraded regularly to support scientific research efficiently. The design, construction, and applications of the CSHINE reported by this study have shown its importance in studying nuclear and particle physics. Thus, this study contributes to the materialization of UNSDG 9: Industries, Innovation & Infrastructure, in which one of the goal’s main targets is to enhance scientific research.

不断创新以及技术进步可以帮助我们有效应对经济及环境方面的双重挑战，对此业界已形成广泛共识。为了实现不断进步，我们需要对设备和工具进行研发和升级，从而有效为科研提供支持和助力。本报告中所论及的CSHINE，无论是在设计、建造，还是在应用方面，都显示出其在核物理及粒子物理研究中的重要性。因此说，该项研究将有助于实现联合国可持续发展17个目标中的第9个目标(UNSDG 9)，即工业、创新和基础设施，而提升科研水平便是这一目标的主要内容之一。