Radiation Protection - Theoretical Lec4. PDF

Radiation protection – Theoretical Lec4. Radiation Quantities And Units Asst.Lec.Nibras Hayder Hmood Radiation Quantities and Units  Activity  Exposure  Absorbed Dose  Equivalent dose  Effective Dose Activity  The rate of decay, or the number of nuclei of a radionuclide d...

Radiation protection – Theoretical Lec4. Radiation Quantities And Units Asst.Lec.Nibras Hayder Hmood Radiation Quantities and Units  Activity  Exposure  Absorbed Dose  Equivalent dose  Effective Dose Activity  The rate of decay, or the number of nuclei of a radionuclide decaying per second is known as its activity.  Units of Activity:  The SI unit of activity is Becquerel (Bq)  The old classical unit is Curie (Ci).  Exposure  The quantity exposure describes an x-ray or gamma ray field. It is a measure of the amount of ionization produced in air by the x-rays or gamma rays in air.  The SI unit of exposure is C/kg  The old classical unit is Roentgen (R) Absorbed Dose  Absorbed Dose:(Any medium, any type of radiation)  The ionizing radiation energy absorbed per unit mass of the matter is known as absorbed dose.   Units of absorbed dose  The SI unit of absorbed dose is J/kg and the special name is Gray (Gy)  1 Gy = 1J/kg  The old classical unit is Rad  1 Rad = 100 ergs/g  Equivalent Dose  Equivalent Dose is a quantity which takes into effect 'radiation quality', which relates to the degree to which ionizing Radiation will produce biological damage.  resulting quantity can then be expressed numerically in Equivalent Dose = Radiation Weighting Factor () Dose (D)  SI: Sieverts (Sv)  The old units: Rem  The quantity is independent of the absorbing material a(i.e. tissue). Radiation Weighting Factor () for some radiations  The Effective Dose  TheEffective Dose is obtained by taking a Tissue Weighting Factor () and multiplying by the Equivalent Dose () which relates to the organs / tissues under consideration. Units Sv or Rem