DETECTOR OF REACTOR ANTINEUTRINOS BASED ON POLYSTYRENE-BASED PLASTIC SCINTILLATORS

AbstraktAbstract

This doctoral thesis is devoted to the development and the construction of the S3 - detector of reactor antineutrinos based on plastic scintillators. This thesis describes the S3 detector from the very beginning, from development and optimization of the basic detector element to the construction of the full-scale S3 detector (40 40 40 cm3). The experimental part is divided to three important sections describing basic detector element, a 2-channel S3 prototype and an 80-channel S3 detector. Our main aim was to optimize the basic detector element to achieve the energy resolution and photoelectron yield as well as possible. Very signicant progress was done in the development of the gadolinium based neutron conversion layers. The thesis describes the progress from hand-made gadolinium converters to professionally developed and produced converters intended for large-area detectors, e.g. S3. The proper analysis of the shielding efect and background measurements, in which pattern of the neutrino interaction was searched for are also presented in this work. The S3 detector together with a complex shielding and corresponding electronics is now under operation and is prepared to be installed under the nuclear power reactor. The S3 experiment represents completely new detector in the eld of the neutrino physics. Its compactness and intuitive control make it an ideal candidate for using it in the reactor building. Moreover, it does not contain any dangerous, toxic, caustic materials. Therefore it is absolutely safe to install the detector in the close vicinity of the reactor ( 10-15 m). Small distance from the reactor core allows us to study neutrino properties with higher eciency, e.g. investigation of short-baseline neutrino oscillations and possibly searching for sterile neutrino. Moreover, the S3 detector can be used for more practical applications like real-time measurement of reactor power, measurement of isotopic composition of reactor fuel or reactor tomography if we use more S3 detectors.

This doctoral thesis is devoted to the development and the construction of the S3 - detector of reactor antineutrinos based on plastic scintillators. This thesis describes the S3 detector from the very beginning, from development and optimization of the basic detector element to the construction of the full-scale S3 detector (40 40 40 cm3). The experimental part is divided to three important sections describing basic detector element, a 2-channel S3 prototype and an 80-channel S3 detector. Our main aim was to optimize the basic detector element to achieve the energy resolution and photoelectron yield as well as possible. Very signicant progress was done in the development of the gadolinium based neutron conversion layers. The thesis describes the progress from hand-made gadolinium converters to professionally developed and produced converters intended for large-area detectors, e.g. S3. The proper analysis of the shielding efect and background measurements, in which pattern of the neutrino interaction was searched for are also presented in this work. The S3 detector together with a complex shielding and corresponding electronics is now under operation and is prepared to be installed under the nuclear power reactor. The S3 experiment represents completely new detector in the eld of the neutrino physics. Its compactness and intuitive control make it an ideal candidate for using it in the reactor building. Moreover, it does not contain any dangerous, toxic, caustic materials. Therefore it is absolutely safe to install the detector in the close vicinity of the reactor ( 10-15 m). Small distance from the reactor core allows us to study neutrino properties with higher eciency, e.g. investigation of short-baseline neutrino oscillations and possibly searching for sterile neutrino. Moreover, the S3 detector can be used for more practical applications like real-time measurement of reactor power, measurement of isotopic composition of reactor fuel or reactor tomography if we use more S3 detectors.