Münster 2017 – wissenschaftliches Programm
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T: Fachverband Teilchenphysik
T 112: Experimentelle Techniken der Astroteilchenphysik 6
T 112.2: Vortrag
Donnerstag, 30. März 2017, 17:00–17:15, S 9
Monitoring high electron fluxes using PIN diodes — •Enrico Ellinger — Bergische Universität Wuppertal
The Forward Beam Monitor (FBM) will be used in KATRIN to monitor the relative intensity of the electron beam produced by the tritium source with a precision of 0.1 %. Furthermore, beta spectra are taken for additional analysis. At the measuring position high fluxes of up to 106 e/s· mm2 with relatively low energies of maximum 18.6 keV are expected. Such measurements make great demands on the detector which consists of a PIN diode, a transimpedance amplifier and a digital pulse processor. The long term stability of such measurements is strongly influenced by temperature changes as well as internal and external noise sources. In particular, the high event rate close to the detection threshold leads to systematic errors in case of detector drifts.
The dead layer of the Hamamatsu PIN diodes influences the measurements because the electrons lose energy passing through it. Therefore, the thickness of the dead layer and possible changes over time need to be estimated. Electron sources were used to determine the effective dead layer thickness and simulations have been performed and compared to the measurement results. Furthermore, an ultra high vacuum manipulator enables the FBM to perform all measurements along the whole flux tube with a positioning precision of better than 0.1 mm. The current status and latest results will be presented.