Speaker
Description
The commissioning of a proton cyclotron for hadron therapy at the Cyclotron Centre Bronowice (CCB) of the Institute of Nuclear Physics of the Polish Academy of Sciences (IFJ PAN) in Krakow has enabled the use of proton beams for nuclear physics experiments. Among others, an experimental campaign was carried out aiming at study the γ decay from excited atomic states, such as giant and pygmy resonances.
The employed experimental method was based on coincidence measurement of scattered protons registered by the KRATTA [1] array and gamma rays emitted from the decay of excited nuclei measured using LaBr$_3$ detectors together with PARIS [3] phoswiches.
One of the main goals of the experiments was to study a very rare phenomenon – the decay of GQR (giant quadrupole resonance) via γ-ray emission to the ground state. Previously such phenomenon was observed only once, in 1980s [3]. In recent experiment we have confirmed the existence of the GQR gamma-decay and measured the branching ratio between GQR gamma decay to ground state and neutron emission for $^{208}$Pb [4]. Similar measurements were also performed for $^{120}$Sn.
During the talk the experimental method, the used equipment as well as the obtained results will be presented. In addition, the outlook for the continuation of such studies will be discussed.
References
[1] J. Łukasik et al., Nucl. Instrum. Methods Phys. Res., Sect. A709, 120 (2013);
[2] A. Maj et al., Acta Phys. Pol. B 40, 565 (2009);
[3] J.R. Beene, et al., Phys. Rev. C 39, 1307 (1989);
[4] B. Wasilewska et al., Phys. Rev. C 105, 014310 (2022).