The new bremsstrahlung facility at the superconducting electron accelerator ELBE

Dipole-strength distributions in the nuclides 98 Mo and 100 Mo up to the neutron-separation energies have been studied in photon-scattering experiments at the bremsstrahlung facility of the Forschungszentrum Dresden-Rossendorf. To determine the dipole-strength distributions up to the neutron-emission thresholds, statistical methods were developed for the analysis of the measured spectra. The measured spectra of scattered photons were corrected for detector response and atomic background by simulations using the code GEANT3. Simulations of γ -ray cascades were performed to correct the intensities of the transitions to the ground state for feeding from higher-lying levels and to determine their branching ratios. The photoabsorption cross sections obtained for 98 Mo and 100 Mo from the present (γ, γ ) experiments are combined with (γ, n) data from literature, resulting in a photoabsorption cross section covering the range from 4 to about 15 MeV of interest for network calculations in nuclear astrophysics. Novel information about the low-energy tail of the giant dipole resonance and its energy dependence is derived. The photoabsorption cross sections deduced from the present photon-scattering experiments are compared with existing data from neutron capture and 3 He-induced reactions.

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“…This technique and further details of the bremsstrahlung facility at the ELBE accelerator are described in Refs. [41,42].…”

Section: Resultsmentioning

confidence: 99%

Low-energy tail of the giant dipole resonance inMo98andMo100

et al. 2008

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“…relative efficiency that are surrounded by escape-suppression shields consisting of bismuth-germanate (BGO) scintillation detectors. The experimental procedure has been described in detail elsewhere [14,15].…”

Section: Methodsmentioning

confidence: 99%

Photoactivation experiment onAu197and its implications for the dipole strength in heavy nuclei

et al. 2008

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The 197 Au(γ, n) reaction is used as an activation standard for photodisintegration studies on astrophysically relevant nuclei. At the bremsstrahlung facility of the superconducting electron accelerator ELBE (Electron Linear accelerator of high Brilliance and low Emittance) of Forschungszentrum Dresden-Rossendorf, photoactivation measurements on 197 Au have been performed with bremsstrahlung endpoint energies from 8.0 to 15.5 MeV. The measured activation yield is compared with previous experiments as well as with calculations using Hauser-Feshbach statistical models. It is shown that the experimental data are best described by a two-Lorentzian parametrization with taking the axial deformation of 197 Au into account. The experimental 197 Au(γ, n) reaction yield measured at ELBE via the photoactivation method is found to be consistent with previous experimental data using photon scattering or neutron detection methods.

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“…In order to study the photodisintegration reactions on 92 Mo and 144 Sm, photoactivation measurements are being performed at the bremsstrahlung facility of the superconducting electron accelerator ELBE (Electron Linear accelerator of high Brilliance and low Emittance) of FZ Dresden-Rossendorf [12,13]. ELBE delivers electron beams of energies up to 20 MeV with average currents up to 1 mA which is appropriate for probing photon-induced reactions.…”

Section: Methodsmentioning

confidence: 99%

Photodisintegration studies on p-nuclei: the case of Mo and sm isotopes

Nair

Junghans

Erhard

et al. 2007

J. Phys. G: Nucl. Part. Phys.

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In explosive stellar environments like supernovae, the temperatures are high enough for the production of heavy neutron-deficient nuclei, the socalled p-nuclei. Up to now, the knowledge of the reaction rates of p-nuclei is based on theoretical parameterizations using statistical model calculations. At the bremsstrahlung facility of the superconducting electron accelerator ELBE of FZ Dresden-Rossendorf, we aim to measure the photodisintegration rates of heavy nuclei experimentally. Photoactivation measurements on the astrophysically relevant p-nuclei 92 Mo and 144 Sm have been performed with bremsstrahlung end-point energies from 10.0 to 16.5 MeV. First experiments on the short-lived decays following the reaction 144 Sm(γ,n) are carried out using a pneumatic delivery system for rapid transport of activated samples. The activation yields are compared with calculations using cross sections from recent Hauser-Feshbach models.

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The new bremsstrahlung facility at the superconducting electron accelerator ELBE

Cited by 17 publications

References 8 publications

Low-energy tail of the giant dipole resonance inMo98andMo100

Low-energy tail of the giant dipole resonance inMo98andMo100

Photoactivation experiment onAu197and its implications for the dipole strength in heavy nuclei

Photodisintegration studies on p-nuclei: the case of Mo and sm isotopes

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