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Measurement of particle yields induced by 200-MeV protons on multiple targets

Lopez, Rafael Antonio LU (2018) FYSK02 20181
Nuclear physics
Department of Physics
Abstract
One way to probe the structure of atomic nuclei far from stability is via quasi-free scattering (QFS) reactions. We conducted a (p,2p) QFS experiment on H2O, 112Sn, 124Sn and 208Pb targets in order to test the performance of CsI(Tl) detectors that are to be used in the upcoming R3B experiments at FAIR. With the help of particle tracking and reconstructive particle identification (RPID) cuts based on CsI(Tl) and Si detector data, we identified different light particle yields from the targets and (p,2p) events. An indication of a (p,2p) reaction to the ground state of 111In was observed from the
112Sn target. Furthermore, a 6.3-MeV gamma ray was seen in coincidence with (p,2p) events in the H2O target. This corresponds to the 3/2- to 1/2-... (More)
One way to probe the structure of atomic nuclei far from stability is via quasi-free scattering (QFS) reactions. We conducted a (p,2p) QFS experiment on H2O, 112Sn, 124Sn and 208Pb targets in order to test the performance of CsI(Tl) detectors that are to be used in the upcoming R3B experiments at FAIR. With the help of particle tracking and reconstructive particle identification (RPID) cuts based on CsI(Tl) and Si detector data, we identified different light particle yields from the targets and (p,2p) events. An indication of a (p,2p) reaction to the ground state of 111In was observed from the
112Sn target. Furthermore, a 6.3-MeV gamma ray was seen in coincidence with (p,2p) events in the H2O target. This corresponds to the 3/2- to 1/2- transition energy in 15N. The experiment was therefore successful in detecting (p,2p) reactions using the new detector systems and at the same time gave directions for future studies. (Less)
Popular Abstract
The modern way of investigating subatomic structures in physics is by shooting small particles at a target and see what happens. You can compare this to the opening play of pool. You aim at the center, and you hope to see some balls scatter. As physicists we have the advantage of controlling the force and angle of the shot very precisely, and can therefore make clear-cut measurements.

By sending high-energy protons at different targets one can learn how their nuclear structures
differ from one another. Why do they have different properties? How come one is stable and the other is not? Why are some better suited at certain reactions?

In this thesis, among the targets investigated were water and two kinds of tin with a different... (More)
The modern way of investigating subatomic structures in physics is by shooting small particles at a target and see what happens. You can compare this to the opening play of pool. You aim at the center, and you hope to see some balls scatter. As physicists we have the advantage of controlling the force and angle of the shot very precisely, and can therefore make clear-cut measurements.

By sending high-energy protons at different targets one can learn how their nuclear structures
differ from one another. Why do they have different properties? How come one is stable and the other is not? Why are some better suited at certain reactions?

In this thesis, among the targets investigated were water and two kinds of tin with a different number of neutrons. It is of interest to examine how the nuclear structure of tin depends on its constituents. Hence, by observing different outcomes from the tin targets we can get a better understanding of their differences in their nuclear structure.

By using parts of a detector that will be implemented in the upcoming Facility for Antiproton and Ion Research (FAIR) in Germany, we accomplished good measurements while at the same time testing it for unknown issues or potential improvements. The detector that is going to be used in FAIR is called CALIFA. When a particle from a reaction flies into the detector, it bounces around and then ends up transferring its energy to a material known as the scintillator. The scintillator in this case is a sort of crystal called the thallium activated cesium iodide, CsI(Tl), and is a popular choice in current days as they are relatively efficient and manageable.

As the material becomes excited from all the energy, it then emits light that is amplified in an
avalanche-like process by an electronics device. From here, the light is converted into an electrical signal that can be read by a computer. The data from the signal is then sifted through using software in which one can make analyses of the particle energies, at which angles they occurred, how they relate to each other and more.

In this study, by using different approaches of identifying particles we managed to see signature energy emissions corresponding to clean proton knockouts in one of the tin targets and water. Furthermore, this experiment was just a small part of a greater plan. The hope is that in FAIR scientists will be able to address questions and puzzles that have previously remained a mystery to us by doing similar experiments, but with much higher energies, more complex reactions and a more complete version of the detector. The answers to the evolution of the universe, structure of matter and creation of fusion plasmas are just samples of what might come from this. (Less)
Please use this url to cite or link to this publication:
author
Lopez, Rafael Antonio LU
supervisor
organization
course
FYSK02 20181
year
type
M2 - Bachelor Degree
subject
keywords
QFS, Quasi-free Scattering, 16O, 112Sn, 124Sn, FAIR, CsI(Tl), R3B, 6.3-MeV gamma, CALIFA, (p, 2p)
language
English
id
8956002
date added to LUP
2018-08-20 15:51:29
date last changed
2018-08-20 15:51:29
@misc{8956002,
  abstract     = {{One way to probe the structure of atomic nuclei far from stability is via quasi-free scattering (QFS) reactions. We conducted a (p,2p) QFS experiment on H2O, 112Sn, 124Sn and 208Pb targets in order to test the performance of CsI(Tl) detectors that are to be used in the upcoming R3B experiments at FAIR. With the help of particle tracking and reconstructive particle identification (RPID) cuts based on CsI(Tl) and Si detector data, we identified different light particle yields from the targets and (p,2p) events. An indication of a (p,2p) reaction to the ground state of 111In was observed from the
112Sn target. Furthermore, a 6.3-MeV gamma ray was seen in coincidence with (p,2p) events in the H2O target. This corresponds to the 3/2- to 1/2- transition energy in 15N. The experiment was therefore successful in detecting (p,2p) reactions using the new detector systems and at the same time gave directions for future studies.}},
  author       = {{Lopez, Rafael Antonio}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Measurement of particle yields induced by 200-MeV protons on multiple targets}},
  year         = {{2018}},
}