CERN Accelerating science

The $s$-process path between Fe and Co. The neutron densities during the $s$ process have to be sufficiently high to overcome the rather short-lived isotope $^{59}$Fe ($t_{1/2}=45$~d).

The R$^3$B setup at GSI optimized for detecting neutrons in the exit channel. The beam enters Cave C after passing the FRS (bottom, left), passes several detectors used for incoming identification and hits the target in the center of th crystal ball (half of the ball is drawn). Afterwards charged fragment and neutrons are separated by the ALADIN magnet. The fragments are bent to the right analysed with a suite of scintillator detectors while the neutrons remain unchanged and are detected with LAND.

Incoming particle identification at the R$^3$B setup.

Left: Mass identification of different ion isotopes after requiring an incoming $^{60}$Fe ions a a neutron detected by LAND. Right: Spectra shown on the left subtracted such that only the mass distribution of Coulomb breakup events are left.

Left: Mass identification of different ion isotopes after requiring an incoming $^{60}$Fe ions a a neutron detected by LAND. Right: Spectra shown on the left subtracted such that only the mass distribution of Coulomb breakup events are left.

Impact of the $^{135}$I(n,$\gamma$) rate on the final abundances of the i process. This reaction rate affects most of the abundances beyond $^{135}$I and is therefore of global importance.

The R$^3$B setup at GSI optimized for charge-exchange reactions with low-energy neutrons in the exit channel. The LENA detector, optimized for the detection of low-energy neutrons emitted at high angles can be seen surrounding the target area. In forward direction, LaBr$_3$ detectors have been used to detect the decay of excited states.

Left: Incoming identification plot. Right: Coulomb breakup cross section of $^{11}$Be at almost 500~AMeV.

Left: Incoming identification plot. Right: Coulomb breakup cross section of $^{11}$Be at almost 500~AMeV.

Left: The $rp$-process path at light elements. Right: The R$^3$B setup at GSI optimized for detecting protons in the exit channel. In particular the proton drift chambers are of importance.

Left: The $rp$-process path at light elements. Right: The R$^3$B setup at GSI optimized for detecting protons in the exit channel. In particular the proton drift chambers are of importance.

(Preliminary data) Left: The reaction rate for the important $^{30}$S(p,$\gamma$)$^{31}$Cl bottleneck reaction in the $rp$ process. Maximum peak temperatures in the $rp$ process are typically around 2~GK. Three contributions can be seen, from (a) the low-lying resonance, (b) the direct capture, and (c) the second excited state in $^{31}$Cl. Right: Comparison of different previous estimations with the reaction rate derived in this work (left). a) Iliadis et al. (red) \cite{IDS01}, b) Wallace and Woosley (blue) \cite{WaW81} and c) Wrede et al (black) \cite{WCC09}. Especially in the low-temperature region, a deviation of up to 4 orders of magnitudes is observed.

(Preliminary data) Left: The reaction rate for the important $^{30}$S(p,$\gamma$)$^{31}$Cl bottleneck reaction in the $rp$ process. Maximum peak temperatures in the $rp$ process are typically around 2~GK. Three contributions can be seen, from (a) the low-lying resonance, (b) the direct capture, and (c) the second excited state in $^{31}$Cl. Right: Comparison of different previous estimations with the reaction rate derived in this work (left). a) Iliadis et al. (red) \cite{IDS01}, b) Wallace and Woosley (blue) \cite{WaW81} and c) Wrede et al (black) \cite{WCC09}. Especially in the low-temperature region, a deviation of up to 4 orders of magnitudes is observed.