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TRISTAN Data Acquisition Development and Systematics Studies for KATRIN

Year: 2025
Type: dissertation
Abstract: Although neutrinos are the most abundant particles in the universe, some of their properties remain unknown to us, in part due to their small interaction cross sections.Model-independent measurements of neutrino properties can be performed through precision measurements of electrons produced in $\upbeta$-decays.The KArlsruhe TRItium Neturino (KATRIN) experiment places the most stringent laboratory upper limit on the effective electron neutrino mass, $m_{\nu} < \SI{0.45}{\electronvolt} \, (90\% \, \text{C.L.})$, through an integral measurement of the tritium spectrum.Near the end of $2025$, KATRIN will reach its design goal of 1000 days of data taking and become a systematics dominated experiment, limited by source effects and background electrons.After this, the TRISTAN detector upgrade is slated to use the KATRIN beamline to search for keV scale sterile neutrinos through a differential measurement of the $\upbeta$-decay spectrum with nine 166-pixel silicon drift detectors.Statistical sensitivities to sterile-to-active mixing of $\sin^2(\theta) = 10^{-6}$ are projected within months of operation. This dissertation outlines the development and testing of the Data Acquisition (DAQ) system for TRISTAN that will enable the precision readout of $\mathcal{O}(1000)$ pixels operating at $100$ kcps each, called the Remote Analog-to-Digital Conversion (RADC) DAQ.Waveform readout and filtering performance of an RADC demonstrator are presented along with the design of the TRISTAN RADC system. Systematic effects that distort the measured $\upbeta$-decay spectrum weaken the ability to constrain the sterile neutrino mixing. An updated modeling of ADC non-linearity induced distortions is developed along with methods of distortion mitigation.Operation of the DAQ system with the proposed mitigation strategies is shown to decrease the projected sensitivity to $\sin^2(\theta)$ by a factor of less than 1.002, which is negligible in comparison to dominant systematics that can decrease the sensitivity by factors of $\mathcal{O}(10)$. Additional studies of systematics in the KATRIN experiment are presented, including the reduction of background and increased statistical power of a potential differential measurement of the neutrino mass afforded by performing a time-of-flight measurement with an electron tagger.Limitations to the technologies that are applicable to non-destructive measurement of passing electrons are discussed, along with a proposal of utilizing cyclotron radiation, inspired by recently demonstrated Cyclotron Radiation Electron Spectroscopy measurements.
DOI: 10.17615/h25e-sd92
Language: English
Open Access status: green
OpenAlex ID: W6925302953
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