arXiv subjects

E. W. Otten

Publications and source records attributed to E. W. Otten.

5 recordsLinked to original sources

arXiv2013

Ultra-stable implanted 83Rb/83mKr electron sources for the energy scale monitoring in the KATRIN experiment

The KATRIN experiment aims at the direct model-independent determination of the average electron neutrino mass via the measurement of the endpoint region of the tritium beta decay spectrum. The electron spectrometer of the MAC-E filter type is used, requiring very high stability of the electric filtering potential. This work proves the feasibility of implanted 83Rb/83mKr calibration electron sources which will be utilised in the additional monitor spectrometer sharing the high voltage with the main spectrometer of KATRIN. The source employs conversion electrons of 83mKr which is continuously generated by 83Rb. The K-32 conversion line (kinetic energy of 17.8 keV, natural line width of 2.7 eV) is shown to fulfill the KATRIN requirement of the relative energy stability of +/-1.6 ppm/month. The sources will serve as a standard tool for continuous monitoring of KATRIN's energy scale stability with sub-ppm precision. They may also be used in other applications where the precise conversion lines can be separated from the low energy spectrum caused by the electron inelastic scattering in the substrate.

physics.ins-det↗

arXiv2010

Effect of a sweeping conductive wire on electrons stored in the Penning trap between the KATRIN spectrometers

The KATRIN experiment is going to search for the mass of the electron antineutrino down to 0.2 eV/c^2. In order to reach this sensitivity the background rate has to be understood and minimised to 0.01 counts per second. One of the background sources is the unavoidable Penning trap for electrons due to the combination of the electric and magnetic fields between the pre- and the main spectrometer at KATRIN. In this article we will show that by sweeping a conducting wire periodically through such a particle trap stored particles can be removed, an ongoing discharge in the trap can be stopped, and the count rate measured with a detector looking at the trap is reduced.

physics.ins-det↗

arXiv2010

Feasibility of photoelectron sources for testing the energy scale stablity of the KATRIN beta-ray spectrometer

Photoabsorption of nuclear gamma-rays in thin metallic convertors was examined with the aim to produce monoenergetic photoelectrons of kinetic energy around 18.6 keV and natural width of about 1 eV. Calculations were carried out for commercial photon sources of 241Am (1.1 GBq) and 119mSn (0.5 GBq) irradiating Co and Ti convertors. Photoelectrons ejected by 241Am gamma- and X-rays from Co convertors of various thickness were measured with two electrostatic spectrometers.

nucl-ex↗

arXiv2009

Neutrino mass limit from tritium beta decay

The paper reviews recent experiments on tritium beta spectroscopy searching for the absolute value of the electron neutrino mass $m(ν_e)$. By use of dedicated electrostatic filters with high acceptance and resolution, the uncertainty on the observable $m^2(ν_e)$ has been pushed down to about 3 eV$^2$. The new upper limit of the mass is $m(ν_e) < 2$ eV at 95% C.L. In view of erroneous and unphysical mass results obtained by some earlier experiments in beta decay, particular attention is paid to systematic effects. The mass limit is discussed in the context of current neutrino research in particle- and astrophysics. A preview is given of the next generation of beta spectroscopy experiments currently under development and construction; they aim at lowering the $m^2(ν_e)$-uncertainty by another factor of 100, reaching a sensitivity limit $m(ν_e) < 0.2$ eV.

hep-ex↗

arXiv2005

Final Results from phase II of the Mainz Neutrino Mass Search in Tritium $β$ Decay

The paper reports on the improved Mainz experiment on tritum $β$ spectroscopy which yields a 10 times' higher signal to background ratio than before. The main experimental effects and systematic uncertainties have been investigated in side experiments and possible error sources have been eliminated. Extensive data taking took place in the years 1997 to 2001. A residual analysis of the data sets yields for the square of the electron antineutrino mass the final result of $m^2(ν_e)=(-0.6 \pm 2.2_{\rm{stat}} \pm 2.1_{\rm{syst}})$ eV$^2$/c$^4$. We derive an upper limit of $m(ν_e)\leq 2.3$ eV/c$^2$ at 95% confidence level for the mass itself.

hep-ex↗