The response of detector telescopes becomes complex around their relevant punch through energies: For some deposited energies the corresponding particle kinetic energies cannot be uniquely assigned, ...and these spurious energy regions can span several hundreds of keV if the telescopes are employed in close geometry. We present methods for producing clean low-energy spectra of light ions from detector telescopes consisting of thin double-sided silicon strip detectors (DSSSDs) backed by thick silicon pad detectors. By following these methods, the spectra of several such detector telescopes can be combined to span the entire relevant particle energy spectrum, above as well as below the punch through thresholds of the individual telescopes. The total energy spectrum resulting from the combination of all telescope spectra thus encompass the entire particle energy distribution in conjunction with the energy-dependent, setup-specific solid angle coverage. Energy spectra of beta-delayed proton emission from 21Mg are used to illustrate the methods.
Presently under construction in Lund, Sweden, the European Spallation Source (ESS) will be the world’s brightest neutron source. As such, it has the potential for a particle physics program with a ...unique reach and which is complementary to that available at other facilities. This paper describes proposed particle physics activities for the ESS. These encompass the exploitation of both the neutrons and neutrinos produced at the ESS for high precision (sensitivity) measurements (searches).
We use a sequential R-matrix model to describe the breakup of the Hoyle state into three α particles via the ground state of Be8. It is shown that even in a sequential picture, features resembling a ...direct breakup branch appear in the phase-space distribution of the α particles. We construct a toy model to describe the Coulomb interaction in the three-body final state and its effects on the decay spectrum are investigated. The framework is also used to predict the phase-space distribution of the α particles emitted in a direct breakup of the Hoyle state and the possibility of interference between a direct and sequential branch is discussed. Our numerical results are compared to the current upper limit on the direct decay branch determined in recent experiments.
Detailed study of the decay of $$^{32}$$Ar Blank, B.; Adimi, N.; Alcorta, M. ...
The European physical journal. A, Hadrons and nuclei,
01/2021, Letnik:
57, Številka:
1
Journal Article
Extended time-interval analysis Fynbo, H.O.U.; Riisager, K.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
2014, Letnik:
735
Journal Article
Recenzirano
Odprti dostop
Several extensions of the halflife analysis method recently suggested by Horvat and Hardy are put forward. Goodness-of-fit testing is included, and the method is extended to cases where more ...information is available for each decay event which allows applications also for e.g. gamma decay data. The results are tested with Monte Carlo simulations and are applied to the decays of 64Cu and 56Mn.
The 23Na(α, p)26Mg reaction has been identified as having a significant impact on the nucleosynthesis of several nuclei between Ne and Ti in Type Ia supernovae, and of 23Na and 26Al in massive stars. ...The reaction has been subjected to renewed experimental interest recently, motivated by high uncertainties in early experimental data and in the statistical Hauser-Feshbach models used in reaction rate compilations. Early experiments were affected by target deterioration issues and unquantifiable uncertainties. Three new independent measurements instead are utilizing inverse kinematics and Rutherford scattering monitoring to resolve this. In this work we present directly measured angular distributions of the emitted protons to eliminate a discrepancy in the assumptions made in the recent reaction rate measurements, which results in cross sections differing by a factor of 3. We derive a new combined experimental reaction rate for the 23Na(α, p)26Mg reaction with a total uncertainty of 30% at relevant temperatures. Using our new 23Na(α, p)26Mg rate, the 26Al and 23Na production uncertainty is reduced to within 8%. In comparison, using the factor of 10 uncertainty previously recommended by the rate compilation STARLIB, 26Al and 23Na production was changing by more than a factor of 2. In Type Ia supernova conditions, the impact on production of 23Na is constrained to within 15%.
Broad resonances and beta-decay Riisager, K.; Fynbo, H.O.U.; Hyldegaard, S. ...
Nuclear physics. A,
August 2015, 2015-08-00, Letnik:
940
Journal Article
Recenzirano
Beta-decay into broad resonances gives a distorted lineshape in the observed energy spectrum. Part of the distortion arises from the phase space factor, but we show that the beta-decay matrix element ...may also contribute. Based on a schematic model for p-wave continuum neutron states it is argued that beta-decay directly to the continuum should be considered as a possible contributing mechanism in many decays close to the driplines. The signatures in R-matrix fits for such decays directly to continuum states are discussed and illustrated through an analysis of the beta-decay of 8B into 2+ states in 8Be.
Detailed study of the decay of 21Mg Jensen, E. A. M.; Nielsen, S. T.; Andreyev, A. ...
The European physical journal. A, Hadrons and nuclei,
07/2024, Letnik:
60, Številka:
7
Journal Article
Recenzirano
Odprti dostop
Beta-delayed proton and gamma emission in the decay of
21
Mg has been measured at ISOLDE, CERN with the ISOLDE Decay Station (IDS) set-up. The existing decay scheme is updated, in particular what ...concerns proton transitions to excited states in
20
Ne. Signatures of interference in several parts of the spectrum are used to settle spin and parity assignments to highly excited states in
21
Na. The previously reported
β
p
α
branch is confirmed. A half-life of 120.5(4) ms is extracted for
21
Mg. The revised decay scheme is employed to test mirror symmetry in the decay and to extract the beta strength distribution of
21
Mg that is compared with theory.
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