0000000000387746
AUTHOR
K. Keck
Streuung von 50 keV-Elektronen an flüssigem Helium
The behaviour of liquid helium in relation to electron-scattering has been investigated. Electrons of 50 keV have been scattered by thin targets of liquid helium with temperatures between 1.34 and 2.15 K. The thickness of targets was chosen between 0.047 and 0.62 mm. The angular distribution and the energy loss of the scattered electrons have been measured in dependence on the thickness of layer and on temperature. The extrapolated range of electrons in liquid helium has been determined.
Isothermal flow of helium II through plane slits
Measurements are reported on the isothermal, gravitational flow of liquid He II through narrow plane slits. The employed superleak consists of ring-shaped Hostaphan foils packed in layers. The distance between the foils is varied by pressure. The performance of the measurements and the observance of the isothermal conditions are described. The velocity of the superfluid component of He II is calculated in dependence on the width of the slits, the temperature and the hydrostatic pressure. Especially the critical velocity is considered.
Streuung von mittelschnellen Elektronen an Kunststoff-Folien mit eingelagerten Schwermetallatomen
Scattering has been observed of 70-keV electrons by Kollodium-foils containing elements of high atomic number (lead). The contents of lead are determined and the kind of distribution of lead in the foil is described. The differential cross-section as a function of the angle of scattering approximates the cross-section calculated by Sherman with lower contents of lead of the foils. Remaining deviations can be explained by screening-effects of the electron cloud.
Kunststoff-Folien mit eingelagerten Schwermetallatomen f�r Elektronenstreuung
Completing a former paper about scattering experiments with electrons a new foil containing an element of high atomic number (lead) has been produced, which shows a very equal and fine distribution of lead.