No abstract available

[en] A new type of spectrometer for low energy charged particles is presented. It consists of an adiabatic magnetic collimation and two filters: an electrostatic retarding potential to set a lower limit (high pass) and a time-of-flight analysis to reject high energy charged particles (low pass). Both filters are only limited in their resolution by the efficiency of the adiabatic magnetic collimation. The proof of this principle is demonstrated by a pilot measurement on the K conversion line of ^83mKr. Possible applications to pulsed and continuous electron sources are discussed with the emphasis on the investigation of the β spectrum of T₂ to deduce information on the mass of the electron antineutrino and possible anomalies in the β spectrum. In this context design parameters of a spectrometer with a resolving power of E/ΔE=20 000 and a luminosity of A ΔΩ/4π=4 cm² for 20 keV electrons are given

No abstract available

No abstract available

[en] With the evidence for massive neutrinos from recent ν-oscillation experiments, one of the most fundamental tasks of particle physics over the next years will be the determination of the absolute mass scale of neutrinos, which has crucial implications for cosmology, astrophysics and particle physics. The KArlsruhe TRItium Neutrino (KATRIN) experiment is the next-generation direct neutrino mass experiment with a sensitivity to sub-eV ν-masses. It combines an ultra-luminous windowless gaseous molecular tritium source with a high resolution electrostatic retarding spectrometer (MAC-E filter) to measure the spectral shape of β-decay electrons close to the endpoint at 18.6 keV with unprecedented precision. If no neutrino mass signal is found, the KATRIN sensitivity after 3 years of measurements is mν0.2eV/c2 (90 % C.L.); a ν-mass signal of mν=0.35eV/c2 can be measured with 5 σ evidence

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No abstract available

[en] The presently lowest limit for the mass of the electron neutrino is mν < 2.2 eV (95 % C.L.) derived from measurements at Mainz up to 1999. The data taken in 2000 are not fully analyzed yet but limits of possible distortions as reported by the Troitsk group can be given. The next generation neutrino mass experiment KATRIN is briefly discussed

[en] The present status of the Mainz tritium β decay experiments is given. The very recent improvement of the Mainz setup and the first results from tritium data are presented. The former trend towards negative values of m²_ν for increasing data intervals was identified to be a roughening transition of the quench-condensed T₂ film, which now can be avoided

[en] The present status of the Mainz tritium β decay experiments is given. The very recent improvement of the Mainz setup and the first results from tritium data are presented. The former trend towards negative values of m²_ν for increasing data intervals was identified to be a roughening transition of the quench-condensed T₂ film, which now can be avoided