arXiv subjects

M. Korzeczek

Publications and source records attributed to M. Korzeczek.

23 records · Page 2Linked to original sources

arXiv2018

Calibration of high voltages at the ppm level by the difference of $^{83\mathrm{m}}$Kr conversion electron lines at the KATRIN experiment

The neutrino mass experiment KATRIN requires a stability of 3 ppm for the retarding potential at -18.6 kV of the main spectrometer. To monitor the stability, two custom-made ultra-precise high-voltage dividers were developed and built in cooperation with the German national metrology institute Physikalisch-Technische Bundesanstalt (PTB). Until now, regular absolute calibration of the voltage dividers required bringing the equipment to the specialised metrology laboratory. Here we present a new method based on measuring the energy difference of two $^{83\mathrm{m}}$Kr conversion electron lines with the KATRIN setup, which was demonstrated during KATRIN's commissioning measurements in July 2017. The measured scale factor $M=1972.449(10)$ of the high-voltage divider K35 is in agreement with the last PTB calibration four years ago. This result demonstrates the utility of the calibration method, as well as the long-term stability of the voltage divider.

physics.ins-det↗

arXiv2018

Reduction of stored-particle background by a magnetic pulse method at the KATRIN experiment

The KATRIN experiment aims to determine the effective electron neutrino mass with a sensitivity of $0.2\,{\text{eV}/c^2}$ (90\% C.L.) by precision measurement of the shape of the tritium \textbeta-spectrum in the endpoint region. The energy analysis of the decay electrons is achieved by a MAC-E filter spectrometer. A common background source in this setup is the decay of short-lived isotopes, such as $\textsuperscript{219}$Rn and $\textsuperscript{220}$Rn, in the spectrometer volume. Active and passive countermeasures have been implemented and tested at the KATRIN main spectrometer. One of these is the magnetic pulse method, which employs the existing air coil system to reduce the magnetic guiding field in the spectrometer on a short timescale in order to remove low- and high-energy stored electrons. Here we describe the working principle of this method and present results from commissioning measurements at the main spectrometer. Simulations with the particle-tracking software Kassiopeia were carried out to gain a detailed understanding of the electron storage conditions and removal processes.

physics.ins-det↗

arXiv2017

A White Paper on keV Sterile Neutrino Dark Matter

We present a comprehensive review of keV-scale sterile neutrino Dark Matter, collecting views and insights from all disciplines involved - cosmology, astrophysics, nuclear, and particle physics - in each case viewed from both theoretical and experimental/observational perspectives. After reviewing the role of active neutrinos in particle physics, astrophysics, and cosmology, we focus on sterile neutrinos in the context of the Dark Matter puzzle. Here, we first review the physics motivation for sterile neutrino Dark Matter, based on challenges and tensions in purely cold Dark Matter scenarios. We then round out the discussion by critically summarizing all known constraints on sterile neutrino Dark Matter arising from astrophysical observations, laboratory experiments, and theoretical considerations. In this context, we provide a balanced discourse on the possibly positive signal from X-ray observations. Another focus of the paper concerns the construction of particle physics models, aiming to explain how sterile neutrinos of keV-scale masses could arise in concrete settings beyond the Standard Model of elementary particle physics. The paper ends with an extensive review of current and future astrophysical and laboratory searches, highlighting new ideas and their experimental challenges, as well as future perspectives for the discovery of sterile neutrinos.

hep-ph↗

arXiv2016

Impact of ADC non-linearities on the sensitivity to sterile keV neutrinos with a KATRIN-like experiment

ADC non-linearities are a major systematic effect in the search for keV-scale sterile neutrinos with tritium $β$-decay experiments like KATRIN. They can significantly distort the spectral shape and thereby obscure the tiny kink-like signature of a sterile neutrino. In this work we demonstrate various mitigation techniques to reduce the impact of ADC non-linearities on the tritium $β$-decay spectrum to a level of $<$ ppm. The best results are achieved with a multi-pixel ($\geq10^4$ pixels) detector using full waveform digitization. In this case, active-to-sterile mixing angles of the order of $\sin^2 θ= 10^{-7}$ would be accessible from the viewpoint of ADC non-linearities. With purely peak-sensing ADCs a comparable sensitivity could be reached with highly linear ADCs, sufficient non-linearity corrections or by increasing the number of pixels to $\geq 10^5$.

physics.ins-det↗

arXiv2015

Wavelet Approach to Search for Sterile Neutrinos in Tritium $β$-Decay Spectra

Sterile neutrinos in the mass range of a few keV are candidates for both cold and warm dark matter. An ad-mixture of a heavy neutrino mass eigenstate to the electron neutrino would result in a minuscule distortion - a 'kink' - in a $β$-decay spectrum. In this paper we show that a wavelet transform is a very powerful shape analysis method to detect this signature. For a tritium source strength, similar to what is expected from the KATRIN experiment, a statistical sensitivity to active-to-sterile neutrino mixing down to $\sin^2 θ= 10^{-6}$ ($90\%$ CL) can be obtained after 3 years of measurement time. It is demonstrated that the wavelet approach is largely insensitive to systematic effects that result in smooth spectral modifications. To make full use of this analysis technique a high resolution measurement (FWHM of $\sim100$~eV) of the tritium $β$-decay spectrum is required.

hep-ph↗