# Radiation Units - KSU Faculty

Radiation Units 1-Radioactivity Units Physical Units Becquerel Amount of radioactive sample s.t. there is 1 atomic decay per second Henri Becquerel: discovered radioactivity through

experiments with uranium and other radioactive matter Curie (Ci) 3.7*1010 decays per second Approx. activity of 1g radium 2-Exposure units (Roentgen(abbreviated 'R'

The roentgen is a unit for measuring exposure. It is defined only for effect on air. The roentgen is essentially a measure of how many ion pairs are formed in a given volume of air when it is exposed to radiation. Therefore it is not a measure of energy absorbed, or dose. It applies only to gamma and x-rays. It does not relate the amount of exposure to biological effects of radiation in the human body.

The roentgen describes the amount of xrays or gamma rays to which a target (e.g., fly, mouse, rat, dog, human, cow, elephant, etc.) is exposed. The roentgen relates to the ability of x-rays and gamma rays to remove electrons from atoms in one cm3 of air. 1 R (Roentgen) = 1000 mR (milliRoentgen) 3- Biological Units

Rad (Radiation Absorbed Dose) The rad is a unit for measuring absorbed dose in any material. Absorbed dose results from energy being deposited by the radiation. It is defined for any material. It applies to all types of radiation. It does not take into account the potential effect that different types of radiation have on the body.

Therefore, it can be used as a measure of energy absorbed by the body, but not as a measure of the relative biological effect (harm or risk) to the body. 1 rad = 1000 millirad (mrad) 1 gray= 100 rad

The radiation absorbed dose is important for describing radiation effects. The absorbed dose relates to how much radiation energy gets put into a given target mass (e.g., lung, eye, thyroid gland). The absorbed dose has units of energy divided by mass (e.g., ergs per gram or joules per kilogram

Different absorbed doses can arise in different organs or tissue of the body for the same exposure in R. Thus, if a person were exposed to 10 R of gamma rays, the eye, the thyroid, and the lung would have different absorbed doses. Special computer programs can calculate such doses. Units of absorbed dose often used are the rad and gray (an SI unit).

The gray unit represents 1 joule of radiation energy put into a kilogram mass. Thus, 1 gray equals 1 joule per kilogram. The gray and rad apply to all types of ionizing radiation, unlike the roentgen unit, which only applies to x-rays and gamma rays.

Biological Units Radiation-Protection Units: Equal doses of different types or energies of radiation cause different amounts of damage to living tissue. For example, 1 Gy of alpha radiation causes about 20 times damage as 1 Gy of x- rays. Therefore the equivalent dose was defined to give

an approximate measure of the biological effect of radiation. It is calculated by multiplying the absorbed dose by a weighting factor W R which is different for each type of radiation . Relative Biological Effectiveness (RBE) or weighting factor W R WR X rays, gamma rays, electrons, positrons 1 Neutrons, protons (10 -100 Ke V)

10 Neutrons, protons (less than 10 Ke V ) 5 Alpha particles 20 Law of the rem (introduced here for the first time to help understand its use):

The risk of harm from 1 rem to an organ from one radiation source = the risk of harm from 1 rem to that organ from any other radiation source! Question 1 Enumerate the different radiation units?, their definition and their relationship?

## Recently Viewed Presentations

• Geography of Europe. ... Atlantic Ocean. SS6G8 (a) Locate on a world and regional political-physical map: the Danube River Rhine River, ... Iberian Peninsula- With the Pyrenees Mountains to the north, this peninsula is made up of Portugal and Spain.
• Intro to JavaScript . Basic Syntax. Goals for today. Today we want to learn about: Fundamental programming structures. Basic JS Syntax. Drawing functions (lines, rectangles, circles, etc.) Program design . More pedagogy techiques. We will apply that knowledge to a...
• * Reading Anchor Standard 1 Read closely to determine what the text says explicitly and to make logical inferences from it; cite specific textual evidence when writing or speaking to support conclusions drawn from the text. Writing Anchor Standard 9...
• Name of work stream: Sam Sherrington. Name(s) of work stream lead: FD/CFO Declarations Initial Cohort & Promotion Publication and Roll Out. Project Outline. Launch FD Declarations with FLC/SROs (6th May 2014) Self actioning- FDs to download, sign and populate comms...
• The reality of this great mystery is manifested throughout the Christmas season in the solemnity of the Holy Family of Jesus, Mary and Joseph, in the celebration of Mary, the Mother of God on New Year's Day and the Epiphany...
• Chemical Breakdown. Chemistry Methamphetamine's chemical name is (S)-N,a-Dimethylbenzene-ethanamine; d-N-methylamphetamine and the chemical formula is C10H15N.Methamphetamine is created by attaching a methyl group to the side chain of an amphetamine As shown in the images.
• This seems inappropriate because the illiquidity discount should be smaller for some firms - larger, healthier firms with more liquid assets - and larger for other firms. This regression used NASDAQ stocks in December 2000. The data on bid-ask spreads...
• "The Gift of the Magi" O. Henry Allusion A reference in one work of literature to a historical event, person, or another work of literature, often used to deepen the meaning of the story. According to Christian tradition, the Magi...