Beek, Patrick van (2021):
Towards Dipole Strength Measurements Using Total Photoabsorption: NEPTUN Upgrade and Commissioning. (Publisher's Version)
Darmstadt, Technische Universität,
DOI: 10.26083/tuprints-00019761,
[Ph.D. Thesis]
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Item Type: | Ph.D. Thesis | ||||
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Status: | Publisher's Version | ||||
Title: | Towards Dipole Strength Measurements Using Total Photoabsorption: NEPTUN Upgrade and Commissioning | ||||
Language: | English | ||||
Abstract: | One of the central questions in astrophysics is the origin of the elements and the connection with cosmological events such as supernovae and neutron star mergers. The equation of state for nuclear matter bridges the gap between cosmological processes on the one hand and atomic nuclei in the microcosm on the other. Measuring the dipole strength of atomic nuclei can contribute to a better understanding of the equation of state, which is the basic motivation of the present dissertation. The photon tagger NEPTUN was fundamentally upgraded within the scope of this work, with the aim of establishing dipole response measurements via total photoabsorption at this setup. The new components are presented and their design is explained. The focus lies on the new focal plane detector LARISSA and the also new photoabsorption setup. Furthermore, various Monte-Carlo simulations of the setup are presented. These were used, inter alia, to model the generation of bremsstrahlung photons and to optimize the design of the photoabsorption setup. Detailed estimates concerning a proposed photoabsorption experiment on 48-Ca are also performed based on these simulations. It is demonstrated that meaningful results can be obtained even though it is expected that there is a very limited amount of target material. First experimental data was recorded in a measurement campaign in December 2018. Here, first photoabsorption measurements were performed on aluminum and water. Later on, measurements with a reduced electron beam energy followed in June 2020. The analysis of the acquired data is presented in detail. Here, the properties of the detectors used are examined, focusing in particular on the new detector LARISSA. Subsequently, the total photonuclear cross sections of aluminum and oxygen are extracted from the recorded data set and the corresponding systematic uncertainties are discussed. A comparison of the results with previous measurements shows good agreement. It is planned for the near future to apply the newly established method to further elements. Of particular interest are the doubly magic nucleus 48-Ca and the single magic isotopes of the element tin. The already well measured nucleus 208-Pb can serve as a further check. |
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Place of Publication: | Darmstadt | ||||
Collation: | xi, 129 Seiten | ||||
Classification DDC: | 500 Naturwissenschaften und Mathematik > 530 Physik | ||||
Divisions: | 05 Department of Physics > Institute of Nuclear Physics > Experimentelle Kernphysik > Experimentelle Kernstruktur und S-DALINAC | ||||
TU-Projects: | DFG|SFB1245|B04 Scheit SFB1245 | ||||
Date Deposited: | 26 Oct 2021 07:19 | ||||
Last Modified: | 26 Oct 2021 07:19 | ||||
DOI: | 10.26083/tuprints-00019761 | ||||
URN: | urn:nbn:de:tuda-tuprints-197610 | ||||
Referees: | Scheit, Priv.-Doz. Heiko ; Aumann, Prof. Thomas | ||||
Date of oral examination: | 18 October 2021 | ||||
URI: | https://tuprints.ulb.tu-darmstadt.de/id/eprint/19761 | ||||
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