Study of collective vibrational modes excited by fast protons in the new CCB facility in Krakow

by Adam Maj (FJ PAN Krakow, Poland)


In 2014, the new proton beam facility Cyclotron Center Bronowice (CCB), with the proton beam energy ranging from 70 to 230 MeV, became operational at the Institute of Nuclear Physics Polish Academy of Sciences in Krakow (Poland). Although the primary objective of the facility is the proton cancer therapy, an extensive research program at this facility is planned in the field of nuclear physics, among others concerning excitation of collective modes by fast protons.

The aim of the first studies was investigation of collective vibrational modes in the 208Pb nucleus. It focused on the study of the gamma decay from high-lying states below and above the particle binding energy excited via fast proton inelastic scattering. Above particle binding, the excitation and gamma-decay of giant resonances, as the giant quadrupole resonance (GQR) and giant dipole resonance (GDR) has been studied. The region below the particle binding energy where, among others, the pygmy dipole states (PDR) are present, was explored as well.

To achieve the goal of the experiment a set-up that enabled a coincidence measurement of high energy γ rays and scattered protons was prepared. To measure the high energy γ rays with high efficiency the HECTOR array [HEC94], consisting of 8 big BaF2 detectors, was used along with the cluster of PARIS type phoswiches (4 LaBr3-NaI and 5 CeBr3-NaI crystals) [PAR09] and large volume LaBr3 scintillator. The angle and energy of the scattered protons was measured with the use of the KRATTA array [KRA13] – a triple telescope made of three photodiodes and two CsI crystals. On the front of the KRATTA array plastic scintillators were mounted to create a trigger with precisely time-defined condition.


The talk will present a need for such studies and the first obtained results. In addition, future plans, also including possible synergy with ELI-NP, will be discussed.