0000000000341411
AUTHOR
R. Gehring
The development of the KATRIN magnet system
The Karlsruhe Tritium Neutrino Experiment KATRIN aims to measure the mass of the electron neutrino with unprecedented accuracy. For this experiment a special magnet system with about 30 LHe bath cooled superconducting magnets grouped in 10 different sections needs to be developed. The magnetic fields required for the electron transport and spectrometer resolution have a level between 3 and 6 T and must be constant in time over months. Further requirements for field homogeneity and tritium compatibility lead to a unique magnet system. A challenging task of this system is to keep the 10 m beam tube of the source magnet at a constant temperature of 30 K with extremely high temperature stabilit…
A line-shape analysis for spin-1 NMR signals
An analytic model of the deuteron absorption function has been developed and is compared to experimental NMR signals of deuterated butanol obtained at the SMC experiment in order to determine the deuteron polarization. The absorption function model includes dipolar broadening and a frequency-dependent treatment of the intensity factors. The high-precision TE signal data available are used to adjust the model for Q-meter distortions and dispersion effects. Once the Q-meter adjustment is made, the enhanced polarizations determined by the asymmetry and TE-calibration methods compare well within the accuracy of each method. In analyzing the NMR signals, the quadrupolar coupling constants could …
PHOSPHORORGANISCHE VERBINDUNGEN 97: Die Diphenylphosphinyl- und die Diphenylthiophosphinylgruppe als selektive Schutzgruppe für die Mercaptofunktion. Nucleophile Ablösung der Thioloestergruppe aus Thiophosphin-, Thiophosphon-und Thiophosphorsäure-S-estern durch nicht solvatisierte Fluoridionen
Abstract Diphenylphosphinsaurecyanid und Diphenylthiophosphinsaurecyanid reagieren selektiv mit der Mercaptogruppe—auch bei Anwesenheit von Verbindungen mit primaren Aminogruppen. Die Thioloesterbindung in Thiophosphin-, Thiophosphon- und Thiophosphorsaure-S-estern wird durch nicht solvatisierte Fluoridionen ([R4N]F°3 H2O (R = C4H9) und CsF) unter schonenden Bedingungen in Chloroform, Methylenchlorid oder THF gespalten. (C6H5)2P(O)CN und (C6H5)2P(S)CN sind als Schutzgruppen-Reagentien fur Mercaptane geeignet. Diphenylphosphinsaurechlorid und Diphenylthiophosphinsaurechlorid sind in Konkurrenzversuchen mit Butylamin/Butylmercaptan N-selektiv. Bei Cysteamin und Cysteinmethylester wird aber im…
PHOSPHORORGANISCHE VERBINDUNGEN 991VERSUCHE ZUR AUFKLÄRUNG DER O-SELEKTIVITÄT VON VERBINDUNGEN MIT DER P(O)F-GRUPPE
Abstract The mechanism of the reaction of phosphoryl fluoride ( P(O)F) with alcohols in the presence of an amine is fundamentally different from the reaction of phosphoryl chlorides ( P(O)Cl) with primary or secondary amines. The following observations strongly support this proposal: 1. 1H-NMR-, 31P-NMR- and 19F-NMR-spectroscopic investigations show that methyl-phenyl-phosphinicacid-fluoride and n-butylamine form a thermolabile adduct, which yields the methyl-phenyl-phosphinicacid-amide only very slowly. 2. The rate of the reaction of methyl-phenyl-phosphinicacid-fluoride with ethanol is independent of the basicity of the amine but very sensitive to steric factors. Imidazole (which is only …
The Cryogenic Pumping Section of the KATRIN Experiment
In order to determine the absolute scale of the neutrino mass with a sensitivity of 0.2 (90% Confidence Level), the Karlsruhe Tritium Neutrino experiment (KATRIN) operates a series of superconducting magnet systems, which guide the electrons adiabatically from the source of tritium beta-decay to the detector within a magnetic flux of 191 . The 7 m long Cryogenic Pumping Section (CPS) is designed as the final barrier of tritium circulation. It has to reduce the tritium partial pressure below Pa in order to limit the background count rate in the measurement. To achieve this, the tritium entering the CPS must be adsorbed onto a pre-condensed argon layer on the inner surface of the beam tube at…
Measurement of proton and nitrogen polarization in ammonia and a test of equal spin temperature
The 1996 data taking of the SMC experiment used polarized protons to measure the spin-dependent structure function g(1) of the proton. Three liters of solid granular ammonia were irradiated at the Bonn electron linac in order to create the paramagnetic radicals which are needed for polarizing the protons. Proton polarizations of +/- (90 +/- 2.5)% were routinely reached. An analysis based on a theoretical line shape for spin-1. systems with large quadrupolar broadening was developed which allowed the nitrogen polarization in the ammonia to be determined with a 10% relative error. The measured quadrupolar coupling constant of N-14 agrees well with earlier extrapolated values. The polarization…