## Roentgen

• It is measurement of energy produced by gamma and x-ray radiations in one cubic centimeter of air.
• It is abbreviated as capital letter "R".
• One milliroentgen (i.e. "mR") is equal to (1/1000) of one roentgen.
• One microroentgen (i.e. "µR") is equal to (1/106) of on roentgen.

## Gray (Gy)

• The System International units for radiation measurements are "gray" (abbreviated as "Gy") and "sivert" (abbreviated as "Sv" ) for absorbed dose & equivalent dose respectively.

• It is abbreviation of "Radiation Absorbed Dose".
• It is measurement unit used for absorption of all types of ionizing radiation viz. alpha, gamma, beta, neutrons into any medium.
• One RAD is equivalent to absorption of 100 ergs of energy per gram of absorbing tissue.

## REM

• It is abbreviation of "Roentgen Equivalent Man".
• It is measurement which correlates dose of any radiation to biological effect of the same radiation.
• All the radiations will have different biological effects and hence dosage is multiplied by quality factor "Q".
• Alpha particles will cause three times more damage compare to gamma rays. Hence alpha radiation has "Q" of 3.

Difference between rad and rem is as follows.
➤REM is measurement of biological effect of the absorbed radiation.

## Conversion between Radiation Units of Measurement

Conversions between one unit and the other are as follows.
➤1 Sv = 100 REM
➤1 mSv = 100 mR (mrem)
➤1Gy (i.e. Gray) = 100 RAD

Following are the links to other useful measurements available on Test and Measurement World website.
Difference between EVM vs subcarriers and EVM vs symbols
Current measurement vs Voltage measurement
Inductance measurement vs Capacitance measurement
Difference between Power and Energy measurements
EMC measurement vs EMI measurement
Electric and Magnetic Field Measurements

## What is difference between or comparison between

Following links mention difference or comparison between various equipments:
comparison between VSG and VSA
DIfference between SNA ans VNA
Oscilloscope Bandwidth versus Rise time
Oscilloscope vs Logic Analyzer
Difference between Oscillscope types
Comparison between spectrum and network analyzer