Abstract
Precise oscillator strengths for seven lines of neutral calcium absorbed from the level 4s4p1P at 2.9 eV above the ground level have been measured using a carbon tube furnace. Additional measurements have been undertaken to link the new measurements to earlier results, obtained using the same equipment, for lines of 2.5 and 2.7 eV excitation. Evidence is presented to show that the set of absorption oscillator strengths, when combined with recent lifetime measurements, establishes an absolute scale of oscillator strengths for neutral calcium which has an uncertainty of only +or-5%. Attention is drawn to some anomalies in other measurements and in calculations of transition probabilities for neutral calcium.