First operation of the KATRIN experiment with tritium

Abstract

The determination of the neutrino mass is one of the major challenges in astroparticle physics today. Direct neutrino mass experiments, based solely on the kinematics of β-decay, provide a largely model-independent probe to the neutrino mass scale. The Karlsruhe Tritium Neutrino (KATRIN) experiment is designed to directly measure the effective electron antineutrino mass with a sensitivity of 0.2 eV (90% CL). In this work we report on the first operation of KATRIN with tritium which took place in 2018. During this commissioning phase of the tritium circulation system, excellent agreement of the theoretical prediction with the recorded spectra was found and stable conditions over a time period of 13 days could be established. These results are an essential prerequisite for the subsequent neutrino mass measurements with KATRIN in 2019.

Improved Upper Limit on the Neutrino Mass from a Direct Kinematic Method by KATRIN

“…In the covariance method, we fit the experimental spectrum RðhqUiÞ with the model R calc ðhqUiÞ by minimizing the standard χ 2 estimator. To propagate the systematic uncertainties, a covariance matrix is computed after performing Oð10 4 Þ simulations of R calc ðhqUiÞ, while varying the relevant parameters for each calculation according to the likelihood given by their uncertainties [35,54,55]. The resulting systematic uncertainties agree with the values shown in Table I, which is based on the second approach.…”

“…For the latter, a stability level of better than 10 −3 =h has been achieved by a two-phase beam-tube cooling system at 30 (100) K using neon (argon) as a cooling fluid [34]. In mid-2018, measurements at 1% DT concentration within a 99% D 2 carrier gas at ρd nom have verified the required level of source stability [35]. This "first tritium" campaign has allowed us to collect the first integral electron spectra which agree well with the model expectation.…”

“…The total uncertainty budget of m 2 ν is largely dominated by σ stat (0.97 eV 2 ) as compared to σ syst (0.32 eV 2 ). As displayed in Table I, the dominant contributions to σ syst are found to be the non-Poissonian background from radon and the uncertainty on the background slope, which is constrained from the wide-energy integral scans of the earlier "first tritium" data [35]. Uncertainties of the column density, energy-loss function, final-state distribution, and magnetic fields play a minor role in the budget of σ syst .…”

Quantitative Long-Term Monitoring of the Circulating Gases in the KATRIN Experiment Using Raman Spectroscopy

“…Finally, we would like to note that temporal evolution data for the molecular components in the LOOPINO campaigns may be found elsewhere [ 41 , 42 ]. Some selected measurement data for the FT campaign are presented in [ 21 ].…”

“…After long years of anticipation, KATRIN was inaugurated in June 2018, and the experiment is fully operational now. Initially, it was run at greatly reduced tritium content in the WGTS [ 21 ], thus keeping radioactive loads at a minimum, to allow for potential repairs and system modifications. Full KATRIN data taking commenced, after tritium ramp-up, during the first quarter of 2019.…”