Nylon Foil Research Articles

Absolute electron-electron differential scattering cross sections at 1.00 Mev, 1.50 Mev, and 2.00 Mev. III

Monoergic electrons were scattered from thin Zapon and Nylon foils. The scattered electrons were observed at 30° in the laboratory system ( ca 90° c.m.) were analyzed by a magnetic spectrometer. The absolute electron-electron scattering cross sections agree with the theory of Møller to within the experimental error of 4%. The broadening of the momentum distribution of the scattered electrons was in reasonable agreement with the theory of Ford and Mullin. The conservation laws for relativistic particles were experimentally verified to an accuracy of 1%.

Scattering of Protons by Hydrogen Near 18 Mev

The differential cross section for the scattering of 18.2\ifmmode\pm\else\textpm\fi{}0.2-Mev protons by hydrogen has been measured over the angular range 30\ifmmode^\circ\else\textdegree\fi{}-90\ifmmode^\circ\else\textdegree\fi{} in the center-of-mass system. In order to reduce the over-all errors to less than 1 percent a 60-in. scattering chamber was used. Polyethylene, polystyrene, and nylon foils were used as scatterers while the proton-proton events were detected by observing coincidences between the scattered and recoil protons in anthracene photomultiplier counters. The incident proton beam was collimated to \ifmmode\pm\else\textpm\fi{}14 minutes of arc. Probable relative errors varied from 0.5 percent at 90\ifmmode^\circ\else\textdegree\fi{} to about 1 percent at 30\ifmmode^\circ\else\textdegree\fi{}, while the probable error in the absolute differential cross section at 90\ifmmode^\circ\else\textdegree\fi{} is estimated to be 1 percent. The data show a significant deviation from pure $S$-wave scattering and are best fitted by taking $S$-, $P$-, and $D$-wave phase shifts to be ${k}_{0}=54.1\ifmmode^\circ\else\textdegree\fi{}$, ${k}_{1}=+1.0\ifmmode^\circ\else\textdegree\fi{}$, ${k}_{2}=+0.4\ifmmode^\circ\else\textdegree\fi{}$, respectively.

Electron-Electron Scattering at 15.7 Mev

The differential scattering cross section for electron-electron scattering has been measured at relativistic energies. A focused beam of 15.7-Mev monokinetic electrons from the 22-Mev betatron was scattered by 1- and 2-mil Nylon foils in a 20-inch scattering chamber. The incident current was collected by a faraday cage after it had passed through the scattering foil and was measured by a vibrating reed electrometer. The scattered beam was defined by gold-lined slits at a known angle to the incident beam. The number of scattered electrons in a given momentum interval chosen by a magnetic analyzer was counted by a Geiger counter.Energy analysis of the scattered electrons made it possible to separate the nuclear scattering events from the electron scattering events. The energy of the scattered electrons was measured as a function of the scattering angle and was found to be in agreement with the laws of relativistic mechanics within an experimental accuracy of 0.4 percent.For the electron-electron collisions the relative scattering cross sections agree with the M\o{}ller formula. For the electron-nuclear collisions they agree with the relativistic Mott theory (Born approximation) corrected for the radiative losses as calculated by Schwinger (3 to 8 percent). The experimental consistency of the cross sections was about 4 percent.The absolute differential scattering cross sections for the electron-nuclear scattering were measured at angles between 10\ifmmode^\circ\else\textdegree\fi{} and 43\ifmmode^\circ\else\textdegree\fi{}. The average of the absolute values was 2 percent lower than theory. This is probably due to systematic errors in the solid angle, and in the collection and counting efficiencies.The absolute differential scattering cross sections for electron-electron scattering were measured at the same set of angles, which correspond to the angular interval of 70\ifmmode^\circ\else\textdegree\fi{} to 150\ifmmode^\circ\else\textdegree\fi{} in the center-of-mass system. The average of these absolute cross sections was 7 percent lower than theory predicts. The bulk of the 5 percent additional departure from theory may be due to a systematic error in the measurement of the momentum interval defined by the counter.