Technical design and commissioning of a sensor net for fine-meshed measuring of the magnetic field at the KATRIN spectrometer

摘要

The KArlsruhe TRItium Neutrino experiment (KATRIN) aims to measure the absolute neutrino mass scale with an unprecedented sensitivity of 0.2 eV/c~2 (90% C.L.), using β decay electrons from tritium decay. The kinetic energy of the decay electrons is measured using an electrostatic integrating main spectrometer with magnetic adiabatic collimation and requires a certain magnetic field profile. For the control of the magnetic field in the main spectrometer area two networks of mobile magnetic field sensor units are developed and commissioned. The radial system is operated close to the outer surface of the main spectrometer whereas the vertical one is mounted along vertical planes left and right of the main spectrometer. The sensor setup can take several thousand magnetic field samples at a fine meshed grid, thus allowing to study the magnetic field inside the main spectrometer and the influence of magnetic materials in the vicinity of the main spectrometer.