In order to investigate the motion of electrons as single particles, we have constructed a magnetic bottle, into which electrons are injected by an electron gun, The magnetic bottle field was produced by a pair of air core coils excited by a steady current, A cylindrical vacuum chamber was inserted through the coils, so that its axis coincides with the magnetic axis, Electrons were injected at the center of the bottle and were observed at various positions.
The present paper is the first report of our experiment, by which we aim at understanding qualitative features of the motion of electrons in our device, We are here interested mainly in the effect of scattering by gases on the mirror loss, In order to avoid the shadow effect of the gun as far as possible, electrons were injected as short pulses, so that a fraction of electrons getting rid of colliding with the gun system could be distinguished from those which have collided, The shadow effect was further eliminated by varying the pressure of a gas (He or A) filled in the chamber, The trapping time of injected electrons was deduced essentially from the intensity of slow electrons produced by their collisions with gas atoms and it was found to be accounted for in terms of the single Coulomb scattering. The lifetime of the slow electrons can be qualitatively explained by their atomic scattering.