We have developed and tested an experimental technique for the measurement of low-energy (p,n) reactions in inverse kinematics relevant to nuclear astrophysics. The proposed setup is located at the ...ReA3 facility at the National Superconducting Cyclotron Laboratory. In the current approach, we operate the beam-transport line in ReA3 as a recoil separator while tagging the outgoing neutrons from the (p,n) reactions with the low-energy neutron detector array (LENDA). The developed technique was verified by using the 40Ar(p,n)40K reaction as a probe. The results of the proof-of-principle experiment with the 40Ar beam show that cross-section measurements within an uncertainty of ∼25% are feasible with count rates up to 7 counts/mb/pnA/s. In this article, we give a detailed description of the experimental setup, and present the analysis method and results from the test experiment. Future plans on using the technique in experiments with the separator for capture reactions (SECAR) that is currently being commissioned are also discussed.
This series publishes outstanding monographs and edited volumes that investigate all aspects of Kant's philosophy, including its systematic relationship to other philosophical approaches, both past ...and present. Studies that appear in the series are distinguished by their innovative nature and ability to close lacunae in the research. In this way, the series is a venue for the latest findings in scholarship on Kant.
A new Time-of-flight detector for the R3B setup Heil, M.; Kelić-Heil, A.; Bott, L. ...
The European physical journal. A, Hadrons and nuclei,
16/12, Letnik:
58, Številka:
12
Journal Article
Recenzirano
Odprti dostop
We present the design, prototype developments and test results of the new time-of-flight detector (ToFD) which is part of the R
3
B experimental setup at GSI and FAIR, Darmstadt, Germany. The ToFD ...detector is able to detect heavy-ion residues of all charges at relativistic energies with a relative energy precision
σ
Δ
E
/
Δ
E
of up to 1% and a time precision of up to 14 ps (sigma). Together with an elaborate particle-tracking system, the full identification of relativistic ions from hydrogen up to uranium in mass and nuclear charge is possible.
We have developed and tested an experimental technique for the measurement of low-energy (p,n) reactions in inverse kinematics relevant to nuclear astrophysics. The proposed setup is located at the ...ReA3 facility at the National Superconducting Cyclotron Laboratory. In the current approach, we operate the beam-transport line in ReA3 as a recoil separator while tagging the outgoing neutrons from the (p,n) reactions with the low-energy neutron detector array (LENDA). The developed technique was verified by using the \(^{40}\)Ar(p,n)\(^{40}\)K reaction as a probe. The results of the proof-of-principle experiment with the \(^{40}\)Ar beam show that cross-section measurements within an uncertainty of \(\sim\)25\% are feasible with count rates up to 7 counts/mb/pnA/s. In this article, we give a detailed description of the experimental setup, and present the analysis method and results from the test experiment. Future plans on using the technique in experiments with the separator for capture reactions (SECAR) that is currently being commissioned are also discussed.
The Gamow-Teller strength distribution from ^{88}$Sr was extracted from a
$(t,{}^{3}\text{He}+\gamma)$ experiment at 115 MeV/$u$ to constrain estimates
for the electron-capture rates on nuclei around ...$N=50$, between and including
$^{78}$Ni and $^{88}$Sr, which are important for the late evolution of
core-collapse supernovae. The observed strength below an excitation energy of 8
MeV was consistent with zero and below 10 MeV amounted to $0.1\pm0.05$. Except
for a very-weak transition that could come from the 2.231-MeV $1^{+}$ state, no
$\gamma$ lines that could be associated with the decay of known $1^{+}$ states
were identified. The derived electron-capture rate from the measured strength
distribution is more than an order of magnitude smaller than rates based on the
single-state approximation presently used in astrophysical simulations for most
nuclei near $N=50$. Rates based on shell-model and quasiparticle random-phase
approximation calculations that account for Pauli blocking and
core-polarization effects provide better estimates than the single-state
approximation, although a relatively strong transition to the first $1^{+}$
state in $^{88}$Rb is not observed in the data. Pauli unblocking effects due to
high stellar temperatures could partially counter the low electron-capture
rates. The new data serves as a zero-temperature benchmark for constraining
models used to estimate such effects.
The Gamow-Teller strength distribution from \({}^{88}\)Sr was extracted from a \((t,{}^{3}\text{He}+\gamma)\) experiment at 115 MeV/\(u\) to constrain estimates for the electron-capture rates on ...nuclei around \(N=50\), between and including \(^{78}\)Ni and \(^{88}\)Sr, which are important for the late evolution of core-collapse supernovae. The observed strength below an excitation energy of 8 MeV was consistent with zero and below 10 MeV amounted to \(0.1\pm0.05\). Except for a very-weak transition that could come from the 2.231-MeV \(1^{+}\) state, no \(\gamma\) lines that could be associated with the decay of known \(1^{+}\) states were identified. The derived electron-capture rate from the measured strength distribution is more than an order of magnitude smaller than rates based on the single-state approximation presently used in astrophysical simulations for most nuclei near \(N=50\). Rates based on shell-model and quasiparticle random-phase approximation calculations that account for Pauli blocking and core-polarization effects provide better estimates than the single-state approximation, although a relatively strong transition to the first \(1^{+}\) state in \(^{88}\)Rb is not observed in the data. Pauli unblocking effects due to high stellar temperatures could partially counter the low electron-capture rates. The new data serves as a zero-temperature benchmark for constraining models used to estimate such effects.
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