Dortmund 2021 – scientific programme
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T: Fachverband Teilchenphysik
T 15: Experimental methods I
T 15.6: Talk
Monday, March 15, 2021, 17:15–17:30, To
Ppm precise high voltage: Advanced post regulation and absolute calibration — •Caroline Rodenbeck1, Thomas Thümmler2, and Sascha Wüstling3 — 1Institut für Kernphysik, WWU Münster — 2IKP, Karlsruher Institut für Technologie — 3IPE, Karlsruher Institut für Technologie
The Karlsruhe Tritium Neutrino (KATRIN) has started data taking to determine the neutrino mass using tritium beta decay spectroscopy. Use of a MAC-E filter type spectrometer enables a precise measurement of the spectrum’s endpoint region. For KATRIN to reach its neutrino mass sensitivity target of 0.2 eV/c2 (90% C.L.), the spectrometer’s retarding potential needs to be stable within 60 mV. This requires the system that creates the retarding potential as well as the system that measures it to be stable within 3 ppm at -18.6 kV on a wide range of time scales, from several months down to 1 µs (1 MHz).
Measuring the retarding potential at the ppm level is done using custom-built high-voltage dividers. Their stability has been proven with a variety of calibration methods over more than a decade. More recently, an absolute calibration technique with 1 ppm precision is being used to perform on-site calibrations. The advanced post regulation system – a feedback loop between the post regulation and one of the precision high-voltage dividers – stabilizes the high voltage on a sub-ppm level for time scales down to 1 us.
The talk presents the absolute calibration method and the advanced post regulation system. This project is supported by BMBF under contract number 05A20PMA and HGF.