How to Measure Radiation

Radiation is nothing but particles (like alpha or beta particles) or waves (gamma waves) which have a potential to cause tremendous damage to the human body when exposed to a high dose in a short period of time. This article attempts to explain the ways in which radiation can be measured.


  1. Image titled Measure Radiation Step 1
    Know the units. No measurement is useful if you don't know what the reading actually means. Followed by the magnitude(the number) is a unit.There are many units which are used to measure radiation for different purposes.
    • In the United States, radiation absorbed dose, dose equivalent, and exposure are often measured and stated in the older units called rad, rem, or roentgen (R), respectively. Sometimes these units prove to be too large to use practically so subunits like mrad (mili-rad which is one thousand times smaller than rad) and ╬╝rad (micro-rad which is a million times smaller than rad) are used.
    • The SI system of measure is the official system of measurement and defines two units to count radiation: gray (Gy) and sievert (Sv).
      • The conversion is as follows:
        • 1 Gy = 100 rad
        • 1 mGy = 100 mrad
        • 1 Sv = 100 rem
        • 1 mSv = 100 mrem
  2. Image titled Measure Radiation Step 2
    Use a Geiger Counter. A Geiger counter has a Geiger-Mueller (G-M) Tube which is filled with gas which creates an electrical pulse which is converted to a reading and shown on the meter. It may also have a speaker which turns each interaction into audible clicks.The common readout units are roentgens per hour (R/hr), milliroentgens per hour (mR/hr), rem per hour (rem/hr), millirem per hour (mrem/hr), and counts per minute (cpm)and is usually specified in the manual and is sometimes visible on the display.
    • You may also need a zinc sulfide (ZnS) scintillator probe if you meter doesn't have one built-in. The scintillator probe is sensitive to alpha radiation. A Geiger counter is the most popular radiation measurement tool in the field as it provides a relatively accurate and real-time measurement of the radioactivity in the surrounding area.
  3. Image titled Measure Radiation Step 3
    Use a MicroR meter which has a Sodium Iodide detector. As a crystal of sodium iodide creates a flash of white light when struck by radiation, makes it a useful radiation detector. A sensor converts the flash of light to an electrical signal. This is used as a single channel detector to identify a radioactive substance. MicroR meters also give an audible click when it detects radiation, making it useful to point out the direction of a radioactive substance substance.
    • Portable Multichannel Analyzers are coupled with a multichannel analyzer package and are becoming much more popular and cheap.These instruments automatically display the type of radiation which is present, making them useful when you don't know which type of radiation is present in the surroundings.
  4. Image titled Measure Radiation Step 4
    Use a Neutron REM meter With a Proportional Counter. This device, as the name suggests creates an electrical pulse when a neutron interacts with the apparatus.These counters require a large amount of hydrogenous around them to slow the neutrons down as high speed neutrons will just whiz by without interacting at all.
  5. Image titled Measure Radiation Step 5
    Use an Ion Chamber. An air filled chamber with electrically conductive walls along with a central anode which works at a relatively low voltage. When x-rays or gamma rays interact with the air surrounding the anode, electrons are released which are collected by the anode. The Anode then generates a small current which is measured by the meter and is displayed.The machine gives a reading related to the absorption of radiation by air which needs to be converted to a reading related to absorption by tissue


  • Always check the packaging of the devices.Any distortion can be due to a fall which may have damaged the instrument.
  • Instruments can go only so far. Always use protective gear near hazardous areas, even if a counter says there is low amount of radiation.


  • Always alert others and take steps to protect yourself in case of a radiation leak.
  • Never go close to a radiation source without proper gear.
  • It is better to be safe than to be sorry, take all preventive measures even at the slightest hint of radiation exposure.

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