Advanced digital detector array enhances charged-particle decay studies

Exotic nuclei near and beyond the proton drip line exhibit a range of unique decay processes, including β-delayed proton emission, α decay, and direct proton radioactivity. Spectroscopic studies utilizing high-efficiency, low-threshold detection systems have become essential for exploring the intricate properties of these nuclei.

In nuclear physics research, exotic nuclei play a crucial role as their decay characteristics can provide key clues for revealing the nature of nuclear forces and testing nuclear structure theoretical models. However, due to the extreme rarity and difficulty in measuring these decay processes, related research has always faced numerous challenges.

Enhanced detection capabilities for exotic decay studies

In a study published in the journal Nuclear Science and Techniques, a research team developed an advanced detection system combining a silicon detector array with high-purity germanium (HPGe) detectors, integrated with a high-performance digital readout system operating at a sampling rate of 250 MHz and a resolution of 14 bits.

The waveform digitization technology, through high-speed sampling and precise quantization, converts analog signals into digital signals, enabling the accurate capture of energy, timing, and position information of decay particles, as well as γ-ray coincidence correlations. This multi-parameter measurement capability ensures high-precision tracking of charged-particle decay processes.

The system’s real-time waveform processing and programmable trigger logic setting can accurately reconstruct the decay processes of short-lived nuclei. By employing sophisticated pulse-shape analysis algorithms, the detector array achieves efficient discrimination between different charged particles (such as protons and α particles) based on the shape differences of the pulse signals generated by particles in the detector. Compared with traditional readout systems, this digital solution significantly improves data acquisition efficiency while achieving higher-precision measurements through digital signal processing.

Experimental validation and scientific impact

To evaluate the system’s performance, the researchers conducted β-decay experiments on the proton-rich nucleus ³²Ar and its neighboring nuclei using the Radioactive Ion Beam Line (RIBLL1) at the Heavy Ion Research Facility in Lanzhou (HIRFL). The experimental results showed that when measuring the β decay of ³²Ar, the system successfully captured its decay branches. The results demonstrated the system’s capability to resolve fine structures in the decay process, delivering crucial data for studies of exotic nuclear structures.

Crucially, the system’s high granularity and low detection threshold (as low as approximately 500 keV for protons) make it particularly suited for investigating rare decay modes, such as β-delayed two-proton emission.

In the future, the research team plans to upgrade the detector array into a platform in the High-Intensity heavy-ion Accelerator Facility (HIAF). This advanced platform will provide more powerful research capabilities for cutting-edge studies including exploring exotic nuclear structures, investigating the decay properties of superheavy nuclei, and measuring key nuclear astrophysics reactions.