0000000000783697
AUTHOR
R. Robertson
Calibration of high voltages at the ppm level by the difference of $$^{83{\mathrm{m}}}$$ 83m Kr conversion electron lines at the KATRIN experiment
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 $$^{83{\mathrm{m}}}$$ 83m Kr conversion electron lines with the KATRIN setup, which was demonstrated during KATRIN’s commissioning measurements …
Early outcomes and complications following cardiac surgery in patients testing positive for coronavirus disease 2019: An international cohort study
The outbreak of severe acute respiratory syndromecoronavirus-2, the cause of coronavirus disease 2019 (COVID-19) in December 2019 represented a global emergency accounting for more than 2.5 million deaths worldwide.1 It has had an unprecedented influence on cardiac surgery internationally, resulting in cautious delivery of surgery and restructuring of services.2 Understanding the influence of COVID-19 on patients after cardiac surgery is based on assumptions from other surgical specialties and single-center studies. The COVIDSurg Collaborative conducted a multicenter cohort study, including 1128 patients, across 235 hospitals, from 24 countries demonstrating perioperative COVID-19 infection…
Gamma-induced background in the KATRIN main spectrometer
The KATRIN experiment aims to measure the effective electron antineutrino mass $$m_{\overline{\nu }_e}$$ mν¯e with a sensitivity of $${0.2}\,{\hbox {eV}/\hbox {c}^2}$$ 0.2eV/c2 using a gaseous tritium source combined with the MAC-E filter technique. A low background rate is crucial to achieving the proposed sensitivity, and dedicated measurements have been performed to study possible sources of background electrons. In this work, we test the hypothesis that gamma radiation from external radioactive sources significantly increases the rate of background events created in the main spectrometer (MS) and observed in the focal-plane detector. Using detailed simulations of the gamma flux in the e…
Machine learning risk prediction of mortality for patients undergoing surgery with perioperative SARS-CoV-2: the COVIDSurg mortality score
The British journal of surgery 108(11), 1274-1292 (2021). doi:10.1093/bjs/znab183