Kilogram scale throughput performance of the KATRIN tritium handling system

The Karlsruhe Tritium Neutrino (KATRIN) experiment aims to determine the effective mass of the electron antineutrino by investigating the tritium β-spectrum close to the energetic endpoint. To achieve this, there are stringent and challenging requirements on the stability of the gaseous tritium source. The tritium loop system has the task to provide the 95 %. KATRIN started full tritium operation in early 2019. This paper focusses on the observed radiochemical effects and confirms that non-negligible quantities during initial tritium operation have to be expected

KATRIN: Direct measurement of neutrino masses in the sub-Ev region

The \underline{KA}rlsruhe \underline{TRI}tium \underline{N}eutrino Mass Experiment is a next generation tritium beta decay experiment designed to reach a sensitivity of $0.2~ \mathrm{eV}/\mathrm{c}^2$. KATRIN will allow to investigate the role of the neutrino hot dark matter in the evolution of large scale structures of the universe and will also allow to discriminate between so-called hierarchical and quasi-degenerated neutrino mass models. The status of the first components of the final KATRIN setup will be shown

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 \upbeta 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 $$0.2\hbox { eV}$$0.2eV ($$90\%$$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

Status and perspectives of the Mainz Neutrino Mass Experiment

The Mainz measurement in 1994 is discussed in the view of the problem of "negative m2" obtained in the analysis for larger energy intervals below the endpoint of the p spectrum. A possible explanation due to a roughening transition of T2 film is given. The very recent improvement of the Mainz setup ant a first 4 weeks measurement is presented. An outlook to the perspectives of the present setup and into the future is given

KATRIN background due to surface radioimpurities

The goal of the KArlsruhe TRItrium Neutrino (KATRIN) experiment is the determination of the effective electron antineutrino mass with a sensitivity of 0.2eV/c2 at 90% C.L.11C.L. - confidence level.. This goal can only be achieved with a very low background level in the order of 10mcps22mcps - milli count per second. in the detector region of interest. A possible background source are α-decays on the inner surface of the KATRIN Main Spectrometer. Rydberg atoms, produced in sputtering processes accompanying the α-decays, are not influenced by electric or magnetic fields and freely propagate inside the vacuum of the Main Spectrometer. Here, they can be ionized by thermal radiation and the released electrons directly contribute to the KATRIN background. Two α-sources, 223Ra and 228Th, were installed at the Main Spectrometer with the purpose of temporarily increasing the background in order to study α-decay induced background processes. In this paper, we present a possible background generation mechanism and measurements performed with these two radioactive sources. Our results show a clear correlation between α-activity on the inner spectrometer surface and background from the volume of the spectrometer. Two key characteristics of the Main Spectrometer background – the dependency on the inner electrode offset potential, and the radial distribution – could be reproduced with this artificially induced background. These findings indicate a high contribution of α-decay induced events to the residual KATRIN background.The goal of the KArlsruhe TRItrium Neutrino (KATRIN) experiment is the determination of the effective electron antineutrino mass with a sensitivity of 0.2 eV/c$^2$ at 90% C.L. This goal can only be achieved with a very low background level in the order of 0.01 counts per second. A possible background source is $\alpha$-decays on the inner surface of the KATRIN Main Spectrometer. Two $\alpha$-sources, $^{223}$Ra and $^{228}$Th, were installed at the KATRIN Main Spectrometer with the purpose of temporarily increasing the background in order to study $\alpha$-decay induced background processes. In this paper, we present a possible background generation mechanism and measurements performed with these two radioactive sources. Our results show a clear correlation between $\alpha$-activity on the inner spectrometer surface and background from the volume of the spectrometer. Two key characteristics of the Main Spectrometer background -the dependency on the inner electrode offset potential, and the radial distribution - could be reproduced with this artificially induced background. These findings indicate a high contribution of $\alpha$-decay induced events to the residual KATRIN background

KATRIN background due to surface radioimpurities

The goal of the KArlsruhe TRItrium Neutrino (KATRIN) experiment is the determination of the effective electron antineutrino mass with a sensitivity of 0.2 eV/c$^2$ at 90% C.L. This goal can only be achieved with a very low background level in the order of 0.01 counts per second. A possible background source is $\alpha$-decays on the inner surface of the KATRIN Main Spectrometer. Two $\alpha$-sources, $^{223}$Ra and $^{228}$Th, were installed at the KATRIN Main Spectrometer with the purpose of temporarily increasing the background in order to study $\alpha$-decay induced background processes. In this paper, we present a possible background generation mechanism and measurements performed with these two radioactive sources. Our results show a clear correlation between $\alpha$-activity on the inner spectrometer surface and background from the volume of the spectrometer. Two key characteristics of the Main Spectrometer background -the dependency on the inner electrode offset potential, and the radial distribution - could be reproduced with this artificially induced background. These findings indicate a high contribution of $\alpha$-decay induced events to the residual KATRIN background

First operation of the KATRIN experiment with tritium

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 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 0.2 eV (90% 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