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The study of nuclide production and its properties in the N=126neutron-rich region is prevalent in nuclear physics and astrophysics research. The upcoming High-energy FRagment Separator (HFRS) at the High-Intensity heavy-ion Accelerator Facility (HIAF), an in-flight separator at relativistic energies, is characterized by high beam intensity, large ion-optical acceptance, high magnetic rigidity, and high momentum resolution power. This provides an opportunity to study the production and properties of neutron-rich nuclei around N=126. In this paper, an experimental scheme is proposed to produce neutron-rich nuclei around N=126and simultaneously measure their mass and lifetime based on the HFRS separator; the feasibility of this scheme is evaluated through simulations. The results show that under the high-resolution optical mode, many new neutron-rich nuclei approaching the r-process abundance peak around A=195can be produced for the first time, and many nuclei with unknown masses and lifetimes can be produced with high statistics. Using the time-of-flight corrected by the measured dispersive position and energy loss information, the cocktails produced from 208Pb fragmentation can be unambiguously identified. Moreover, the masses of some neutron-rich nuclei near N=126can be measured with high precision using the time-of-flight magnetic rigidity technique. This indicates that the HIAF-HFRS facility has the potential for the production and property research of neutron-rich nuclei around N=126, which is of great significance for expanding the chart of nuclides, developing nuclear theories, and understanding the origin of heavy elements in the universe.

With the aim of simulating the harsh temperature condition of space, a thallium-activated cesium iodide crystal (CsI:Tl) detector readout with a PIN photodiode (CsI:Tl(PD)) and with a silicon photomultiplier (CsI:Tl(SiPM)) is investigated over a temperature range from − 40 to 40 °C. With the increase in temperature, the output signal increases by ~ 24% with CsI:Tl(PD) and decreases by ~ 69% with CsI:Tl(SiPM). To reduce the effect of temperature in outer space, a method of bias voltage compensation is adopted for CsI:Tl(SiPM). Our study demonstrates that after correcting the temperature the variation in the analog-to-digital converter’s amplitude is < 3%.

Gamma-ray polarimetry is a new and prospective tool for studying extremely high-energy celestial objects and is of great significance for the field of astrophysics. With the rapid development of microsatellite technology, the advantages of space exploration have become increasingly apparent. Therefore, we simulated a soft-gamma-ray polarimeter for a microsatellite based on the Compton scattering principle. We performed detailed Monte Carlo simulations using monoenergetic gamma-ray linear-polarization sources and Crab-like sources in the energy range of 0.1–10 MeV considering the orbital background. The polarimeter exhibited excellent polarization detection performance. The modulation factor was 0.80±0.01, and the polarization angles were accurate within an error of 0.2∘at 200 keV for on-axis incidence. For the Crab-like sources for on-axis incidence, the polarization degrees were consistent with the set values within the error tolerance, the modulation factor was 0.76±0.01, and the minimum detectable polarization reached 2.4% at 3σfor an observation time of 106s. Additionally, the polarimeter exhibited recoil electron tracking, imaging, and powerful background suppression in a large field of view (FoV; ∼2πsr). The proposed polarimeter meets the requirements of a space soft-gamma-ray polarization detector and has promising research prospects.

A fully digital data acquisition system based on a field-programmable gate array (FPGA) was developed for a CsI(Tl) array at the external target facility (ETF) in the Heavy Ion Research Facility in Lanzhou (HIRFL). To process the CsI(Tl) signals generated by γ-rays and light-charged ions, a scheme for digital pulse processing algorithms is proposed. Every step in the algorithms was benchmarked using standard γand αsources. The scheme, which included a moving average filter, baseline restoration, leading-edge discrimination, moving window deconvolution, and digital charge comparison, was subsequently implemented on the FPGA. A good energy resolution of 5.7% for 1.33-MeV γ-rays and excellent α-γidentification using the digital charge comparison method were achieved, which satisfies CsI(Tl) array performance requirements.

A tracking system composed of three multi-wires proportional chambers (MWPCs) for the external target facility of the Cooler Storage Ring is reported in this paper. The active areas of the MWPCs are 518 mm × 400 mm, 582 mm × 450 mm, and 710 mm × 500 mm. Each MWPC consists of a series of alternately placed cathode and anode wire planes and can measure position along the directions of −30°, 0°, and 30° relative to horizontal. The construction and operation of the detectors are described, and a method for track reconstruction is introduced. A track-finding efficiency of about 62% and a spatial resolution of 1.21 mm have been achieved. The pion and proton can be identified clearly with the tracking system combined with a time-of-flight system.

Performance characterization for massive photomultiplier tubes (PMTs) is a frequently encountered procedure in large nuclear and particle experiments. To facilitate this work, a dedicated test bench system has been developed at the Institute of Modern Physics, Chinese Academy of Sciences. The two-dimensional photocathode position scanning capability is an intrinsic function of the test bench, and up to 25 PMTs, with the diameter smaller than 2″, can be tested simultaneously. The parameters of the light source pulses can be adjusted in a wide range, thus making it suitable for various characteristics measurements. The test bench system is highly automated with all the controlling operations integrated into a single software. Additionally, the hardware platform is extensible which allows complex testing schemes, and the modularity in the software design makes the migration from one testing configuration to another light-weight and efficient. All these features make the test bench versatile and reusable in different experiments. It has been first used in the construction of the Plastic Scintillator Detector (PSD) of DArk Matter Particle Explorer (DAMPE), and a total of 570 Hamamatsu R4443 tubes were tested successfully. The performance was verified and the testing results are also reported in this article.

China plans to develop the next generation dark matter particle explorer satellite, referred to as the Very Large Area Space Telescope (VLAST). As an essential step in this process, the prototype design of detectors and electronics for the VLAST is currently underway. The nuclide detector is a core detector in the VLAST. It mainly measures nuclides’ charges and distinguishes high-energy gamma rays and electrons. This paper will discuss the prototype readout electronics for the VLAST’s nuclide detector, which accurately measures the charge signal of the photomultiplier tubes using the VATA160 application-specific integrated circuit chip; furthermore, we consider a series of critical problems, including radiation-hardening and environment monitoring. The test results show that the system exhibits stable operation, good performance, and good technical indicators. Furthermore, each electronic channel achieves a dynamic range of 0–12.5 pC, the random noise level exceeds 1.6 fC, and the integral nonlinearity exceeds 0.35%.

Two new acetylated flavonoid diglycosides, scutellarein-5-O-[α-l-rhamnopyranosyl-(1→4)-β-d-6-O-acetylglucopyranoside] (1), apigenin-5-O-[α-l-rhamnopyranosyl-(1→2)-β-d-3,6-di-O-acetylglucopyranoside] (2), were isolated from the leaves of Cephalotaxus sinensis. Their structures were determined by chemical and spectroscopic methods including HR-FAB-MS, 1H–1H COSY, HSQC and HMBC experiments.