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

ionising radiation Ionizing radiation (or ionising radiation), including nuclear radiation, consists of subatomic particles or electromagnetic waves that have sufficient energy to ionize atoms or molecules by detaching electrons from them. Some particles can travel ...

. Examples of radiation detectors described as ionometers can be found through to the 1950s but the term more often now means a device for measuring the chemical ion concentration of a fluid.

Ionometer (radiation)

An early ionometer is due to the Swiss physicist

Heinrich Greinacher Heinrich Greinacher (May 31, 1880 in St. Gallen – April 17, 1974 in Bern) was a Swiss physicist. He is regarded as an original experimenter and is the developer of the magnetron and the Greinacher multiplier. Greinacher was the only child of ...

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. Greinacher states the advantage of his instrument over Bronson's being in not requiring the quadrant electrometer (invented by

Lord Kelvin William Thomson, 1st Baron Kelvin, (26 June 182417 December 1907) was a British mathematician, mathematical physicist and engineer born in Belfast. Professor of Natural Philosophy at the University of Glasgow for 53 years, he did important ...

). Greinacher also had to invent the practical

voltage doubler A voltage doubler is an electronic circuit which charges capacitors from the input voltage and switches these charges in such a way that, in the ideal case, exactly twice the voltage is produced at the output as at its input. The simplest of thes ...

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.

Ionometer (ion concentration)

Possibly the first use of ionometer with this meaning was by F. E. Bartell. In his paper on the instrument in 1917 he discusses possible names, rejecting

potentiometer A potentiometer is a three-terminal resistor with a sliding or rotating contact that forms an adjustable voltage divider. If only two terminals are used, one end and the wiper, it acts as a variable resistor or rheostat. The measuring instrum ...

as inappropriate, so implying that there was not already a name in existence.Bartell, FE, "A Direct Reading Ionometer", ''J. Am. Chem. Soc.'', 1917, ''39'' (4), pp630–63
retrieved
3rd Jan 2009.

References

Particle detectors Laboratory equipment {{particle-stub