A measurement of the metastable fraction of the n-2 population of hydrogen atoms formed by electron capture of protons in caesium at 2.5 to 10 keV

Reports measurements of the metastable fraction of the n=2 population of hydrogen atoms formed by electron capture of protons in caesium in the energy range 2.5 to 10 keV. The experimental method does not involve the detection of photons and is thus free from the related calibration problems. Measurements are also reported of the ratio of the differential cross sections for negative-ion formation in the forward direction when hydrogen atoms in the 2s and 1s states impinge on helium, neons, krypton, xenon and hydrogen at 3 keV.