Measuring the oscillator strength of intercombination lines of helium-like V ions in a laser-produced-plasma

•The ratio of an optically thick to an optically thin line can be used to measure the oscillator strength of the optically thin transition in cylindrical plasmas.•We have obtained the first experimental results of this method for the intercombination line of the Heα complex at the OMEGA 60 laser.•The results agree with those from the NIST database, showing the potential of this method to measure transition strengths.