Examensarbeten för masterexamen // Master Theses
Länka till denna samling:
Browse
Browsar Examensarbeten för masterexamen // Master Theses efter Ämnesord "Acceleratorfysik och instrumentering"
Visar 1 - 2 av 2
Sökresultat per sida
Sortera efter
- PostOptimised Use of Detector Systems for Relativistic Radioactive Beams(2013) Lindberg, Simon; Chalmers tekniska högskola / Institutionen för fundamental fysik; Chalmers University of Technology / Department of Fundamental PhysicsEver since the discovery of the atomic nucleus, the exploration and understanding of its properties has been a frontier of physics research. Such investigations are still ongoing at different research facilities around the world. One of these places is the GSI accelerator laboratory where experiments with unstable heavy ions are performed. To obtain high-quality results from the experiments, it is essential that the detectors used are performing at their maximum. Hence it is important to understand the characteristics of the detectors to be able to find and correct errors. In this thesis, the response of two different detector systems in the LAND-setup at GSI is investigated. The first detector system is called the Crystal Ball, a γ-detector, which is also able to detect high-energy protons. The second detector type is used for detecting ions. It consists of a long plastic scintillator which is very common in nuclear physics experiments and is used in several different detector systems in the LAND-setup. For the Crystal Ball an evaluation of different addback routines were performed. An addback routine is a method to recreate the multiplicity and energy of γ-rays and protons hitting the Crystal Ball detectors. This was done based on simulations of different scenarios. For the scintillator, experimental data were used. The motivation to investigate the behaviour of the scintillator is a feature causing the detector to respond differently depending on the position of a hit in the paddle. The origin of this behaviour was found and different methods for correction are suggested and evaluated. The third and last topic of this thesis is a brief analysis of data collected by a detector system constructed to find a relation between energies deposited by cosmic muons and protons in the Crystal Ball. With this relation it is possible to calibrate the Crystal Ball for a range of proton energies, using cosmic muons. The results from the experiment agree with expectations, however to find the relation, a more thorough analysis is needed.
- PostProbabilistic Neutron Tracker(2009) Trulsson, Linus; Törnqvist, Hans; Chalmers tekniska högskola / Institutionen för fundamental fysik; Chalmers University of Technology / Department of Fundamental PhysicsIn order to gain further understanding of subatomic physics, research is conducted close to the drip line, where the ratio of the constituents of the nuclear core is at the extreme. In experiments, liberated neutrons, which have no charge, are difficult to detect because only the effects of collisions with charged particles can be observed. Collisions at the subatomic level may involve different physical processes and branch into several other collisions. A neutron detector called LAND, situated in the GSI facility outside Darmstadt, Germany, is capable of observing these collisions. The algorithm currently used to recognize neutrons from the collisions is heavily based on macroscopic observations of how the neutron detector behaves. It is greedy and therefore tends to underestimate the number of neutrons for complicated events. This project continues investigations from an earlier project, aimed at de- signing a probabilistic method to reconstruct neutrons from neutron detector data. Visualisations of the new algorithm show promising results of resolving neutron paths and branching and statistical results show good capabilities in estimating the number of neutrons. Some very important problems could not be solved, but the effects of the problems can be understood and explained from the obtained results. An algorithm based on probability functions of subatomic interactions seems to be a viable concept and will most probably see continued exploration and improvement by future masters students.