ionometer

The term ionometer was originally applied to a device for measuring the intensity of ionising radiation.

Possibly the first use of ionometer with this meaning was by F. E. Bartell.

An early ionometer is due to the Swiss physicist Heinrich Greinacher in 1913.

However, Greinacher was not the first to build an ionometer, he credits one Bronson with building an instrument upon which Greinacher's was an improvement.

Interestingly, Greinacher also had to invent the practical voltage doubler circuit in order to provide the 200-300 V he needed for the ionometer as the 110 V AC supplied by the Zurich power stations of the time were insufficient.