Speaker
Description
The propagation of Ultra-High-energy cosmic rays (UHECR) in extragalactic space has gathered significant attention in the field of high-energy astrophysics. The motivation behind the PANDORA(Photo-Absorbtion of Nuclei and Decay Observation for Reactions in Astrophysics) project lies in investigating the photo-disintegration and energy loss processes experienced by UHECR particles lighter than iron during their interaction with the strongly Doppler-shifted Cosmic Microwave Background (CMB) photons, seen by UHECRs as high-energy gamma rays. Understanding these complex interactions is essential in comprehending the origins of UHECRs and the mechanism responsible for their acceleration to such high energy ranges.
The issue with this particular study is that the data is often sparse and with several inconsistencies between individual measurements.. For heavy nuclei, mainly the (γ, xn) reaction has been investigated and been assumed to be the equal to the total photo-absorbtion cross-section. However, this assumption is not necessarily valid for light nuclei.
One of the methods used follows inelastic proton scattering at 0° with proton energies of hundreds of MeV, which favors excitation of dipole modes by relativistic Coulomb excitation. Another method is to use real gamma rays from a dedicated photon facility. For achieving this goal a joined collaboration between ELI-NP, RCNP and iThemba LABS has been created. In both iThemba and RCNP labs an array of double-sided Si strip detectors and a magnetic spectrometer are used for particle decay and excitation strength. The gamma decay branches will be measured with large-volume LaBr3:Ce detectors. Here we will present the PANDORA project and report preliminary analysis from the first test experiment at RCNP on 12,13C. These measurements can further be used to constrain the propagation and the origin of UHECRs.
