Proton-Knockout Reactions from Neutron-Rich N Isotopes at R3B
One-proton knockout reactions from neutron-rich 17N, 19N, and 21N isotopes have been performed in inverse kinematics at the R3B/LAND setup at GSI in Darmstadt during the experimental campaign S393. They have been measured in a kinematically complete way with a beam energy of 490 AMeV. This thesis...
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| Format: | Others |
| Language: | en |
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2019
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| Online Access: | https://tuprints.ulb.tu-darmstadt.de/8223/7/SyndikusIna_PhDThesis_190620.pdf Syndikus, Ina Josephine <http://tuprints.ulb.tu-darmstadt.de/view/person/Syndikus=3AIna_Josephine=3A=3A.html> (2019): Proton-Knockout Reactions from Neutron-Rich N Isotopes at R3B.Darmstadt, Technische Universität, [Ph.D. Thesis] |
| Summary: | One-proton knockout reactions from neutron-rich 17N, 19N, and 21N isotopes have been performed in inverse kinematics at the R3B/LAND setup at GSI in Darmstadt during the experimental campaign S393. They have been measured in a kinematically complete way with a beam energy of 490 AMeV.
This thesis presents the inclusive and exclusive cross sections of Quasi-Free Scattering (QFS) and knockout reactions and compares them with calculations in the Glauber framework. The results are interpreted in a configuration mixing model describing the first excited 2+ state of the fragments as a mixture of a pure proton and a pure neutron excitation. The comparison of the experimental and theoretical cross sections shows that this description is missing short- and long-range correlations. Furthermore, the proton amplitude for the neutron-rich, even-even 16C, 18C, and 20C isotopes is extracted from the ratio of the exclusive cross sections of the first excited 2+ state and the 0+ ground state of the QFS reactions. The results support the two-state mixing picture. The behavior of the proton amplitude can be explained by the reduction of the spin-orbit splitting of the 1p1/2 and 1p3/2 proton orbit as an effect of the tensor force between the protons and the neutrons in the sd shell. Moreover, it helps to understand the increase of the B(E2;2+ → 0+g.s.) quadrupole transition strength towards the neutron-rich 20C isotope.
The analysis leading to these results is presented in detail.
This includes the identification of the incoming and outgoing particles as well as a discussion of several addback algorithms to reconstruct the γ-ray energies. The number of recorded events and problems with the triggering are identified as the main sources for the experimental uncertainties. The γ-ray spectra are compared to simulations. The simulations have been performed in R3BRoot, a software package making use of the GEANT toolkit dedicated to experiments with the R3B setup. In this context, the proton and γ-ray detection efficiencies of the Crystal Ball detector are discussed.
In addition, two position sensitive silicon prototype detectors which will be used as in-beam tracking detectors in the updated R3B setup have been tested at KVI-CART. Their performance, i.e., their energy and position resolution, is investigated in terms of the integration time of the electronic read out. While the energy resolution is best for large integration times, the position resolution improves with decreasing integration time. These findings are discussed in terms of the noise introduced by the resistive surface of the detectors and the resulting pulse shapes. |
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