Radiant sensors
Radiation sensors convert the incident radiant signal energy (measurand)
into electrical output signals. The radiant signals are either
electromagnetic, neutrons, fast neutrons, fast electrons, or heavy-charge
particles176. The range of electromagnetic frequencies is immense
spanning from cosmic rays on the high end with frequencies in the
1023 rd Hz range to radio waves in the low tens of thousands of Hz.
In manufacturing applications we are most familiar with infrared radiation
(1011 Hz to 1014 Hz) as a basis for temperature measurement
or flaw/problem detection. Silicon-on-insulator photodiodes as well
as phototransistors based on transistor action are typical micro-sensor
radiant devices for use in these ranges176.