Speaker
Description
Time Projection Chambers (TPCs) and silicon (Si) semiconductor detectors are useful to examine residual nuclei in nuclear reaction.
We developed MAIKo and MAIKo+, which are TPC-based active target systems [1]. They enable tracking of low-energy charged particles over a large solid angle by using gas as both the detection medium and target. We utilize them to study triple-alpha reaction, which is one of the most important in nucleosynthesis in the universe. We inject a neutron beam into the MAIKo(+) active targets filled with a detection gas containing carbon, and measure 3 alpha particles emitted from excited states of residual carbon nuclei. A test measurement was conducted at the OKTAVIAN neutron beam facility in Osaka University, and it showed significant potential to measure residual nuclei in nuclear reactions [2].
We also developed a Si detector array SAKRA to detect decay particles from residual nuclei. It has particle-identification capabilities via pulse shape analysis. We demonstrated that SAKRA is capable to distinguish protons from alpha particles at E > 2 MeV and alpha particles from carbon nuclei at E > 5 MeV, and useful to examine decay processes of residual nuclei and to clarify their internal structures. We employed SAKRA to search for alpha cluster states in $^{24}$Mg [3].
In this talk, we will report the performance of MAIKo(+) and SAKRA, and present their application in our recent experimental works.
References
[1]. T. Furuno, T. Kawabata ${\it{et\,al}}$., “Performance test of the MAIKo active target”, Nucl. Instrum. Methods Phys. Res. A $\bf 908$, 215 (2018).
[2]. T. Furuno ${\it{et\,al}}$., “Measurement of $^{12}$C($n,n’$) reaction cross section to determine triple-alpha reaction rate in high-density environments”, EPJ Web of Conf. $\bf 260$, 11010 (2022).
[3]. Y. Fujikawa, T. Kawabata ${\it{et\,al}}$., “Search for the 6$\alpha$ condensed state in $^{24}$Mg using the $^{12}$C + $^{12}$C scattering”, Phys. Lett. B $\bf 848$, 138384 (2023).
