Entwicklung Eines Elektrostatischen Kugelkondensator-Spektrometers Zur Messung des Ruckstob-Protonenspektrums Beim B-Zerfall des Neutrons (An Electrostatic Spectrometer for Measuring the Proton Recoil Spectrum in Neutron Beta Decay)

摘要

This report describes part of the work for an experiment on neutron decay, in which the coefficient of the electron-antineutrino angular correlation is to be determined from a precise measurement of the shape of the proton recoil spectrum. Since a resolution 2 percent and a small entrance aperture for the adjacent detector was required and in view of the low proton energy (752.34 eV maximum), the time-of-flight spectrometer was chosen. Numerical methods were used to determine the smallest possible condensor dimensions, considering the large cross section (38 mm) of the entering proton beam, and taking the fringing field into account. The mesh method was used to calculate the potential near the electrode edges, and the Runge-Kutta-method was used to calculate particle orbits. The minimum central particle orbit necessary is shown to be 300 mm. A hydrogen ion source, consisting of an electron impact source and a Wien-filter, has been used to test the spectrometer. Excellent agreement between measured and calculated particle orbits was found.