0000000001097109
AUTHOR
J. Wolf
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 …
Synthesis, Molecular Structure, and Reactivity of Rhodium(I) Complexes with Diazoalkanes and Related Substrates as Ligands
A series of (diazoalkane)rhodium(I) compounds of the general composition trans-[RhCl(N2CRR‘)(PiPr3)2] with R = R‘ = Ph, p-C6H4Me, p-C6H4Cl and R = Ph, R‘ = p-C6H4Me, o-C6H4Me, CH3, CH2Ph, CF3 has been prepared from the dimer [RhCl(PiPr3)2]2 (1) and the diazoalkane. This preparative route has also been extended to complexes in which the N2C unit(s) of 1,4-C6H4{C(Ph)N2}2, 9-diazofluorene, 9,10-anthraquinone-9-diazide, and 3-methyl-1,4-naphthoquinone-1-diazide is (are) linked to a 14-electron [RhCl(PiPr3)2] fragment. While C(CO2Et)2N2 behaves as expected and affords upon treatment with 1 the complex trans-[RhCl{N2C(CO2Et)2}(PiPr3)2), CH(CO2Et)N2 reacts with the same starting material to give t…
Improved Upper Limit on the Neutrino Mass from a Direct Kinematic Method by KATRIN
We report on the neutrino mass measurement result from the first four-week science run of the Karlsruhe Tritium Neutrino experiment KATRIN in spring 2019. Beta-decay electrons from a high-purity gaseous molecular tritium source are energy analyzed by a high-resolution MAC-E filter. A fit of the integrated electron spectrum over a narrow interval around the kinematic end point at 18.57 keV gives an effective neutrino mass square value of (−1.0−1.1+0.9) eV2. From this, we derive an upper limit of 1.1 eV (90% confidence level) on the absolute mass scale of neutrinos. This value coincides with the KATRIN sensitivity. It improves upon previous mass limits from kinematic measurements by almost a …
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…
Structure and agency in capabilities-enhancing homeless services: Housing first, housing quality and consumer choice
The capabilities approach, a framework for understanding and measuring inequality, stipulates that equality is best understood as the freedom to do and be within a particular context. Homelessness has been referred to as a situation of ‘capabilities deprivation’, and the extent to which homeless services restore or enhance capabilities is of increasing interest. As part of a large, eight-country study of homelessness in Europe, we examined the extent to which adults with histories of perceived the services they receive as capabilities-enhancing. We collected data at two time points: baseline (nt1 = 565) and follow-up (nt2 = 399). Measures included perceived capabilities, choice and housing …
Impact of a cryogenic baffle system on the suppression of radon-induced background in the KATRIN Pre-Spectrometer
The KATRIN experiment will determine the effective electron anti-neutrino mass with a sensitivity of 200 meV/c$^2$ at 90% CL. The energy analysis of tritium $\beta$-decay electrons will be performed by a tandem setup of electrostatic retarding spectrometers which have to be operated at very low background levels of $<10^{-2}$ counts per second. This benchmark rate can be exceeded by background processes resulting from the emanation of single $^{219,220}$Rn atoms from the inner spectrometer surface and an array of non-evaporable getter strips used as main vacuum pump. Here we report on a the impact of a cryogenic technique to reduce this radon-induced background in electrostatic spectrometer…
CCDC 207302: Experimental Crystal Structure Determination
Related Article: H.Werner, N.Mahr, J.Wolf, A.Fries, M.Laubender, E.Bleuel, R.Garde, P.Lahuerta|2003|Organometallics|22|3566|doi:10.1021/om0302037
CCDC 207300: Experimental Crystal Structure Determination
Related Article: H.Werner, N.Mahr, J.Wolf, A.Fries, M.Laubender, E.Bleuel, R.Garde, P.Lahuerta|2003|Organometallics|22|3566|doi:10.1021/om0302037
CCDC 207301: Experimental Crystal Structure Determination
Related Article: H.Werner, N.Mahr, J.Wolf, A.Fries, M.Laubender, E.Bleuel, R.Garde, P.Lahuerta|2003|Organometallics|22|3566|doi:10.1021/om0302037