Speaker
Kathrin Valerius
(Institut für Kernphysik, WWU Münster)
Description
Despite the results of neutrino oscillation experiments providing compelling evidence for non-zero neutrino masses,
the absolute mass scale still remains undetermined.
This question, which has a strong impact on both particle physics and cosmology,
can be addressed in several, complementary ways, either via astrophysical observations or by laboratory experiments.
The direct neutrino mass determination relies on a precise measurement of the $\beta$ spectrum (tritium, $^{187}\textrm{Re}$)
near its endpoint region.
Recent experiments at Mainz and Troitsk using tritium $\beta$ decay have reached their sensitivity potential,
yielding upper limits of about $\unit[2]{eV/c^2}$ for $m(\overline{\nu}_e)$.
The {\bf KA}rlsruhe {\bf TRI}tium {\bf N}eutrino ex\-peri\-ment (KATRIN), designed to reach a sensitivity of
$m(\overline{\nu}_e) = \unit[0.2]{eV/c^2}$ (90\% C.L.), will improve the signal rate by a factor of $> 100$
with respect to previous experiments while maintaining the same low background level at an enhanced energy resolution of
0.93~eV of the spectrometer which is scaled up by a factor of 10 in linear dimensions.
This low background rate can only be achieved by active and passive reduction of the background components induced by the spectrometer itself
and in the detector region. Furthermore, sources of systematic errors such as energy losses inside the tritium source or
fluctuations of the energy scale of the spectrometer need to be carefully controlled and analyzed.
An overview of KATRIN`s method to reduce the background rate and to determine the systematics as well
as the sensitivity on the neutrino mass will be presented.
Authors
KATRIN-Collaboration
Kathrin Valerius
(Institut für Kernphysik, WWU Münster)
