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Test measurement of the <sup>12,13</sup>C (p, p alpha) Reactions for the PANDORA Project

POSTER

Abstract

The PANDORA project plans to investigate photo-nuclear reactions in the mass region below A ∼ 56. The main motivation of this project is to understand the energy loss process of nuclei consisting of ultra-high-energy cosmic rays (UHECRs) in inter-galactic propagation. The origin, acceleration mechanism, and composition of UHECRs are still unknown. However, UHECRs with energies above 1020 eV are observed by large cosmic-ray air-shower observatories such as Pierre Auger and Telescope Array. Analyses of air-shower depth distributions revealed a trend to be heavier in the mass composition between protons and iron at the highest energies.

UHECR nuclei are predicted to primarily lose their energy by emitting particles after photo-nuclear excitation by absorbing a cosmic microwave background (CMB) photon. Therefore, photonuclear reaction cross-sections and decay branching ratios are crucial elements for understanding the energy and mass evolution of UHECRs during inter-galactic propagation.

In the experiment, virtual photon exchange by proton scattering will be used to excite target nuclei and determine the photo-absorption cross-sections covering the giant dipole resonance. The detection of decay particles will extract branching ratios.

Data for the 12,13C (p, p alpha) reactions at 392 MeV were measured in a test experiment in Dec. 2022 and some improvement points were identified.

I will report the status of the experimental setup for a beam time in Oct. 2023.

Presenters

  • Yohei Sasagawa

    Department of physics, Osaka University

Authors

  • Yohei Sasagawa

    Department of physics, Osaka University

  • Atsushi Tamii

    Research Center for Nuclear Physics

  • Shinsuke Ota

    Research Center for Nuclear Physics, Osaka University, RCNP, Osaka University

  • Nobu Kobayashi

    RCNP, Osaka University, Research Center for Nuclear Physics, Osaka University, RCNP, Osaka University

  • Azusa Inoue

    RCNP, Osaka University

  • Ryota Iwasaki

    RCNP, Osaka University

  • Takahiro Kawabata

    Department of Physics, Osaka University, Department of Physics, School of Science, Osaka University, Osaka University, Depertment of Physics, Osaka University

  • Tatsuya Furuno

    Department of Physics, Osaka University, Department of Physics, School of Science, Osaka University, Depertment of Physics, Osaka University

  • Yuya Honda

    Department of Physics, Osaka University, Depertment of Physics, Osaka University

  • Hiroaki Shibakita

    Department of Physics, Osaka University

  • Yuki FUJIKAWA

    Department of Physics, School of Science, Kyoto University, Department of Physics, Kyoto University

  • Satoshi Adachi

    CYRIC, Tohoku University, CYRIC, Tohoku Universty, Cyclotron and Radioisotope Center, Tohoku University, Department of Physics, Osaka University, Cyclotron and Rareisotope Center, Tohoku University

  • Jacob Bekker

    Department of Physics, Witwatersrand University

  • Luna Pellegri

    Department of Physics, Witwatersrand University

  • Retief Neveling

    iThemba LABS

  • P-A Söderström

    ELI-NP, Extreme Light Infrastructure - Nuclear Physics

  • Andreea Gavrilescu

    ELI-NP

  • Motoki Murata

    Research Center for Nuclear Physics, Osaka University, RCNP, Osaka University