Mean Lives of Some States in Atomic Hydrogen

Hydrogen atoms in excited states were produced by passing a beam of fast-moving hydrogen molecules through a thin carbon foil. Radiation from these atoms was studied as a function of time using filtered photomultiplier tubes. Measured values of the mean lives of the $3s$, $3d$, $4s$, $4p$, and $4d$ states in hydrogen are presented and compared with theory. Results of measurements of relative initial intensities of radiation from fine-structure states of the $n=3\mathrm{}$ and $n=4\mathrm{}$ levels in hydrogen are also presented.