Highly-charged stable or radioactive ions can be stored and cooled in a heavy-ion storage ring
offering unprecedented capabilities for precision studies in the realm of atomic, nuclear structure,
and astrophysics [1]. We have employed the unique feature of the Experimental Storage Ring
(ESR) facility at GSI to address astrophysically relevant reactions. In 2009, as a proof-of-concept
experiment, the cross section of 96Ru(p,γ) has been successfully investigated [2]. Later, in 2016 the
study of the 124Xe(p,γ) reaction has been performed with decelerated fully-ionized 124Xe54+ ions [3].
Using a Double Sided Silicon Strip Detector (DSSSD), introduced directly into the Ultra High
Vacuum environment of the storage ring, the 125Cs proton-capture reaction products have been successfully
detected. The cross section is measured at 5 different energies between 5.5 AMeV and 8
AMeV, on the high energy tail of the Gamow-window for hot, explosive scenarios such as super -
novae and X-ray binaries. The well-understood atomic REC cross section for 124Xe54++H2 reaction
is used for luminosity calibration. Elastic scattering on the internal H2 gas jet target is the major
source of background. Monte Carlo simulations show that an additional slit system in the ESR in
combination with the energy information of the Si detector will make background free measurements
of the proton-capture products possible. This improvement is about to be implemented and
will increase the sensitivity of the detection for (p,γ) products tremendously.
In this seminar, the details of the 124Xe(p,γ)125Cs experiment and the data analysis will be
introduced. As an outlook, future perspectives at ESR are discussed [4] focusing on precision (p,γ)
reaction studies in the Gamow-window using stored and cooled, highly charged, radioactive ions.

References
[1] Bosch F et al 2013 Prog. Part. Nucl. Phys. 73 84
[2] Mei B et al 2015 Phys. Rev. C92 035803
[3] Glorius J et al 2019 Phys. Rev. Lett. 122 092701
[4] Woods P J et al 2015 Phys. Scripta T 166 014002