The KATRIN experiment is going to search for the mass of the electron antineutrino down to 0.2eV/
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-like 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.
For the neutrino mass determination experiment KATRIN, the long-term stability of the spectrometer voltage is of crucial importance. Therefore, it is planned to control the voltage continuously in a ...smaller spectrometer, which monitors the position of the conversion electron line emitted in the 32
keV transition in the decay of
83mKr. Due to the short half-life of
83mKr (
t
1/2=1.83
h), it has to be supplied by a long-lived
83mKr(
83Rb) generator (
t
1/2=86
d). Here, a hitherto unexploited method for the efficient production of
83Rb and its suitability for its application in the KATRIN monitor spectrometer is described.
To implement low-power gas sensors with low component costs, the principle of work-function read out via a hybrid suspended gate FET (SGFET) is being pursued, whereby a freely selectable sensor film ...undergoes a reversible work-function change corresponding to the build-up of a potential difference on the surface in response to gas adsorption/reaction. This is read out via an ISFET structure. An innovative design which allows cheap manufacturing will be described for the principle that has already been successfully demonstrated. The starting point of the design is a ceramic Al
2O
3 substrate coated with conductor patterns and sensitive materials onto which the FET is mounted in flip–chip technology. By means of the freely selectable sensor film and its preparation method, a wide range of applications can be opened up.
This paper reports on the improved Mainz experiment on tritium \(\beta\) 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 \(m^2(\nu_e) = (-0.6 \pm 2.2_{\mathrm{{stat}}} \pm 2.1_{\mathrm{{syst}}})\) eV2/c4. We derive an upper limit of \(m(\nu_e)\leq 2.3\) eV/c2 at 95% confidence level for the mass itself.
The CO sensitivity of Pt(NH3)2(NO2)2 and Pd(NH3)2(NO2)2 impregnated SnO2 thick layers was measured by following the work function change, at 90 C. The complexes were decomposed by heat treatments in ...air, in the temperature range of 150-350 C. The composition of the surface layer was studied by XPS. The maximum CO sensitivity, the optimal response and recovery times-measured by Kelvin probe--were found, if PtO or PdO were present on the surface. 9 refs.
Work function gas sensors are normally operating on the principle of potential difference measurements.
In this work, the change of the work function (Δ
Φ) of the Pt (<1 nm)/Cu layer structure was ...studied in function of the sample's heat treatment temperature (23–300°C) in response of 2000 ppm CO using a Kelvin probe with a gold grid reference electrode. The aim of the heat treatment was the forming of the “proper size” Pt clusters by Pt diffusion. It was studied by XPS analysis.
In each case it was found that the introduction of the CO decreases the work function by 6–55 mV at room temperature. The optimal heat treatment conditions were determined, as 200°C, 1 h, when the change of the work function was 9 mV beside 17 s response and recovery times.
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