[en] The KArlsruhe TRItium Neutrino (KATRIN) experiment will measure the mass of the neutrino with a sensitivity of 0.2 eV (90 % CL). The Forward Beam Monitor (FBM) is a monitoring system which comprises of a complex mechanical setup capable of inserting a detector board into the KATRIN beamline at the end of the source and transport section. The detector board contains a Hall sensor, a temperature gauge, and two PIN diodes which can detect electrons from the source with a precision of 0.1 % in less than a minute within an electron flux density of 10⁶ s⁻¹mm⁻². (paper)

[en] Studies of even-even nuclei in the A ∼ 100 transitional mass region within the framework of the interacting boson model-1 (IBM-1) have been expanded down to "9"8Pd nuclei to compare the calculation with new experimental results from measurements obtained at the Institute of Nuclear Physics in Cologne. The low-lying energy levels and the E2 transition rates of "9"8"-"1"0"0Pd nuclei are investigated and their geometric structures are described in the present work. We have also focused on the new B(E2:2_1"+ → 0_1"+) values of "1"1"2","1"1"4Pd nuclei to compare with previously calculated values. It is shown that the new results for the B(E2:2_1"+ → 0_1"+) values of "1"1"2","1"1"4Pd nuclei are more closer to the calculated ones than the earlier experimental data

[en] The neutrino mass experiment KATRIN requires a stability of 3 ppm for the retarding potential at - 18.6 kV of the main spectrometer. To monitor the stability, two custom-made ultra-precise high-voltage dividers were developed and built in cooperation with the German national metrology institute Physikalisch-Technische Bundesanstalt (PTB). Until now, regular absolute calibration of the voltage dividers required bringing the equipment to the specialised metrology laboratory. Here we present a new method based on measuring the energy difference of two ^83mKr conversion electron lines with the KATRIN setup, which was demonstrated during KATRIN's commissioning measurements in July 2017. The measured scale factor M = 1972.449(10) of the high-voltage divider K35 is in agreement with the last PTB calibration 4 years ago. This result demonstrates the utility of the calibration method, as well as the long-term stability of the voltage divider. (orig.)

[en] The KATRIN experiment aims to determine the effective electron neutrino mass with a sensitivity of 0.2 eV/c² (%90 CL) by precision measurement of the shape of the tritium β-spectrum in the endpoint region. The energy analysis of the decay electrons is achieved by a MAC-E filter spectrometer. A common background source in this setup is the decay of short-lived isotopes, such as ²¹⁹Rn and ²²⁰Rn, in the spectrometer volume. Active and passive countermeasures have been implemented and tested at the KATRIN main spectrometer. One of these is the magnetic pulse method, which employs the existing air coil system to reduce the magnetic guiding field in the spectrometer on a short timescale in order to remove low- and high-energy stored electrons. Here we describe the working principle of this method and present results from commissioning measurements at the main spectrometer. Simulations with the particle-tracking software Kassiopeia were carried out to gain a detailed understanding of the electron storage conditions and removal processes. (orig.)