A New Study on Detector Array Paves the Way for DESPEC Experiments

Scientists from the Institute of Modern Physics (IMP) of the Chinese Academy of Sciences, Université Paris-Saclay, and GSI Helmholtzzentrum für Schwerionenforschung GmbH have lately achieved new progress in characterizing the γ detector array, which will be one of the key instruments for DESPEC (DEcay SPECtroscopy) experiments.

As one of NUSTAR (NUclear STructure, Astrophysics and Reactions) pillars, the DESPEC program will be carried out at FAIR (Facility for Antiproton and Ion Research) in Germany. It will enable researchers to investigate exotic nuclei produced in heavy-ion induced fragmentation and fission reactions.

In this study, researchers have investigated the newly designed Hybrid system, which combines FATIMA (fast-timing measurement) and DEGAS (DESPEC Germanium Array Spectrometer) in a new geometry. The new system aims at precise γ-ray spectroscopy studies, especially on the isomeric states survived from a in-flight separator and states populated after the β-decay of the implanted nuclei.

To prove the adequacy of the system, scientists have developed a simulation framework and verified using experimental data from various setups. Several possibilities for placements of the Ge clusters and the fast scintillators, including their exact position in the corresponding array of rings with respect to the entire implantation setup, are all taken into account.

Furthermore, the positioning, distances and thickness of the implantation detectors are included in the study. The effect of γ-ray multiplicities on the detector efficiencies, the beam distribution andγ-ray absorption in inactive detector materials and housing are all characterized.

The revealed result can be used as a guideline for DESPEC experiments. The developed simulation framework will also be used in the nuclear study program at HIAF (High Intensity heavy-ion Accelerator Facility) in China.

This work was supported by the Youth Innovation Promotion Association of Chinese Academy of Sciences, the Strategic Priority Research Program of Chinese Academy of Sciences, and the National Natural Science Foundation of China.

The result was published in Nuclear Instrumentation and Methods in Physics Research A.

Link to the paper: doi.org/10.1016/j.nima.2020.164806