  GAGG(Ce) is a novel scintillator with a fast response and high light output
without a hygroscopic nature. It is expected to be a useful detector for
charged particles at high-counting rates. However, the response of the GAGG(Ce)
scintillator to charged particles has not been fully examined. In the present
work, the light output and energy resolution of the GAGG(Ce) scintillator were
measured for protons and alpha particles at $E_{p}=5$-68 MeV and
$E_{\alpha}=8$-54 MeV as well as gamma rays at $E_{\gamma}=662$ keV from a
$^{137}$Cs source. The results were compared with those of the CsI(Tl)
scintillator. The scintillation efficiencies $dL/dE$ of the GAGG(Ce) and
CsI(Tl) scintillators were obtained and parametrized as a function of linear
energy transfer $dE/dx$.
