7th Asia-Pacific Conference on Plasma Physics, 12-17 Nov, 2023 at Port Messe Nagoya

A multi-channel scintillation counter for GeV-scale multi-species ion
spectroscopy in laser-driven particle acceleration experiments
Y. Abe1,2, H. Kohri3, A. Tokiyasu4, T. Minami1, K. Oda1, T. Yasui1, Y. Sakai1, K. Sakai1, F. Nikaido1,
K. Kuramoto1, K. Iwasaki1, T. Taguchi1, T. Asai5,6, M. Kanasaki5, S. Kodaira7, S. Fujioka2,S. Tanaka8, S. Isayama9, Y. Fukuda6, and Y. Kuramitsu1,2
1Graduate School of Engineering, Osaka University,
2
Institute of Laser Engineering, Osaka University,
3
Research Center for Nuclear Physics, Osaka University,
4
Research Center for Electron Photon Science, Tohoku University,
5
Graduate School of Maritime Sciences, Kobe University,
6
Kansai Photon Science Institute (KPSI), National Institutes for Quantum and Radiological Scienceand Technology (QST),
7
National Institute of Radiological Sciences (NIRS), National Institutes for Quantum andRadiological Science and Technology (QST),
8
College of Science and Engineering, Aoyama Gakuin University,
9
Interdisciplinary Graduate School of Engineering Sciences, Kyushu University
e-mail (speaker): abe.yuki@eei.eng.osaka-u.ac.jp
High-power lasers have shown their unique capabilityof producing ultrashort-pulsed beams of energetic ionswith extremely high current densities, providing
unprecedented opportunities for research in high energy
density physics, nuclear astrophysics, and fusion science.
The growing attention to laser-driven ion sources is also
based on the rapid progress in attainable ion energy andrepetition rate: from multi-MeV to GeV per nucleon andfrom mHz to the order of 10 Hz. Such improved beam
performance makes lasers an interesting alternative toconventional large accelerators, but requires appropriate
modifications to current diagnostic techniques.
Laser-driven ion beams are known to produce multiple
ion species (H+, Cn+, On+ etc.) in picosecond bunch
durations with broad spectra and energy-dependent
divergence angles. Such complex ion properties cannot
be fully characterized by conventional diagnostic
techniques such as Thomson parabola spectrometerbecause of their poor spectral resolution and particle
identification accuracy in the energy range above 100
MeV/nucleon. Therefore, we have developed a new
diagnostic concept based on Particle Counting Analysis(PCA). The diagnosis uses scintillation detectors toprovide a mass-dependent ion energy spectrum based ontime-of-flight and pulse-height analysis of detected
single particle events. With a novel arrangement ofmultiple scintillators with different ions stopping powers,

PCA offers potential advantages over commonly useddiagnostic instruments (CR-39, radiochromic films,Thomson parabola, etc.) in terms of spectral resolution in
sub-GeV range, coverage solid angle, detection
efficiency, and real-time analysis during the experiment.
The basic detector unit was tested using 230-MeV proton
beam from a synchrotron facility, where wedemonstrated its potential ability to discriminate major
ion species accelerated in laser–plasma experiments (i.e.,protons, deuterons, carbon, and oxygen ions) withexcellent energy and mass resolution. The proposed
diagnostic concept would be essential for a better
understanding of laser-driven near-relativistic ion
acceleration [2–4], which paves the way toward
all-optical compact accelerators for a range ofapplications.

References[1] Y. Abe et al., Rev. Sci. Instrum. 93. 063502 (2022)[2] Y. Kurmaitsu et al., Sci. Rep. 12, 2346 (2022)[3] R. Matsui et al., Phys. Rev. Lett. 122, 014804 (2019)[4] S. Isayama et al., Phys. Plasmas 28, 073101 (2021)