Commissioning and Characterization of the Tritium Gas Circulation System of the KATRIN Experiment

The KATRIN (Karlsruhe Tritium Neutrino) experiment aims to measure the mass of the electron anti-neutrino $\overline{\nu}\mathrm{e}withasensitivityof200meV/c²bymeasuringthespectrumofthebetaelectronsclosetothekinematicendpointregion.Thebeta−electronsaregeneratedinawindowlessgaseoustritiumsource(WGTS)consistingofT_2moleculesinsideanenclosingbeam−tubeof10mlength,adiameterof90mmandatatemperatureof30K.Acontinuousfeedofmoleculartritium(40 g/day)intotheWGTSisnecessarytokeepthetritiumpuritystableonthe0.1\epsilon\mathrm{T}>95^{11}decayspersecond.Wepresentresultsofthespring2018commissioningofthegascirculationsystemwithdeuteriumfocussingonsystemcharacterizationandperformance,gasinjectionstabilityandanalysisoftimedependentcompositionalchanges(e.g.exchangebetweenH_2,HD,D_2$) measured by Raman spectroscopy.