| Title: |
Pilot experiments with relativistic uranium projectile and fission fragments thermalized in a cryogenic gas-filled stopping cell ; Pilotexperimente mit in einer kryogene gasgefüllten Stoppzelle thermalisierten relativistischen Projektil- und Spaltfragmenten |
| Authors: |
Reiter, Moritz Pascal |
| Publication Year: |
2023 |
| Collection: |
Publication Server of the Justus-Liebig-University of Giessen |
| Subject Terms: |
Exotische Kerne; Stoppzelle; Alpha Spektroskopie; Isomerverhältnisse; Exotic Nuclei; Stopping cell; Alpha Spectroscopy; Isomeric Ratios; ddc:530 |
| Description: |
High precision experiments and decay spectroscopy of exotic nuclei are of great interest for nuclear structure and nuclear astro-physics. They allow for studies of the nuclear structure far from stability, test of fundamental interactions and symmetries and give important input for the understanding of the nuclear synthesis in the universe. In the context of this work a second generation stopping cell for the low energy branch of the Super-FRS was commissioned at the FRS at GSI and significant improvements were made to the device. The prototype stopping cell is designed as a cryogenic stopping cell (CSC), featuring enhanced cleanliness and high area density. The CSC was brought into full operation and its performance characteristics were investigated including the maximal area density, extraction times, cleanliness and extraction efficiencies. In three commissioning experiments at the current GSI FRS facility in 2011, 2012 and 2014 up to 22 isotopes from 14 elements produced by in-flight projectile fragmentation and fission of 238-U could be thermalized and extracted with high efficiency. For the first time projectile and fission fragmentation produced at 1000 MeV/u could be thermalized in a stopping cell and provided as a low-energy beam of high brilliance for high precision experiments. The technical improvements of the CSC, such as an improved RF carpet, new cryocooler-based cooling system, a monitoring system of the cleanliness and the high density operation, made it possible to thermalize heavy 238-U projectile fragments with total efficiencies of about 20% in the 2014 experiment. In addition the improvements lead to an increase in the stability and reliability of the CSC and the performance of the CSC during online experiments at the FRS Ion Catcher showed that the utilized techniques are ready for the final CSC for the low-energy branch of the Super-FRS at FAIR.The CSC was operated with an area density of up to 6.3 mg/cm^2 helium during online experiments, which is about three times larger than any ... |
| Document Type: |
doctoral or postdoctoral thesis |
| File Description: |
application/pdf |
| Language: |
English |
| Relation: |
http://nbn-resolving.de/urn:nbn:de:hebis:26-opus-118274; https://jlupub.ub.uni-giessen.de//handle/jlupub/10330; http://dx.doi.org/10.22029/jlupub-9714 |
| DOI: |
10.22029/jlupub-9714 |
| Availability: |
http://nbn-resolving.de/urn:nbn:de:hebis:26-opus-118274; https://jlupub.ub.uni-giessen.de//handle/jlupub/10330; https://doi.org/10.22029/jlupub-9714 |
| Rights: |
In Copyright ; http://rightsstatements.org/page/InC/1.0/ |
| Accession Number: |
edsbas.388FCF02 |
| Database: |
BASE |