Ionizing Radiation

Define radiation:

Energy that passes from one location to another

Define ionizing radiation:

Radiation that is capable of removing electrons from an atom

The atom from which the electron is removed becomes a ______ ion

Positive

The electron that is removed can be picked up by a nearby neutral atom, causing it to become a ______ ion

Negative

What are the 2 types of ionizing radiation?

Particulate radiation and electromagnetic radiation

What is particulate radiation made up of?

Particles of solid matter

What is electromagnetic radiation made up of?

Photons

What are alpha particles made up of?

2 protons and 2 neutrons

Why are alpha particles extremely ionizing?

Because of the large mass and relatively high velocity, they have a great deal of kinetic energy

What are beta particles made up of?

an electron

Where are beta particles created and then shot out of?

In the nucleus of some radioactive atoms and then shot out at nearly the speed of light

Why are beta particles less ionizing than alpha particles?

Due to less mass but can travel further into the body

Neutrons:

Shot out of the nucleus of some radioactive atoms (plutonium) and travel near the speed of light

Protons:

Can be ejected by some radioactive atoms and have similar ionization potentials

What are heavy ions composed of?

Particles that are heavier than alpha particles (helium atoms)

Define electromagnetic energy:

Transport of energy through space as a combination of electrical and magnetic fields

How is electromagnetic energy created?

Some type of disturbance in the two fields that coexist with each other at 90 degrees

Define electromagnetic field:

Field of force that consists of both electric and magnetic components, resulting from the motion of an electrical charge and containing a definite amount of electromagnetic energy

What are the disturbances that create electromagnetic energy called?

Rapid oscillation or movement of electrically charged particles

What is the electromagnetic spectrum?

Organized grouping of the various forms of electromagnetic energy

How is the electromagnetic spectrum organized?

Lowest energy to highest energy

What is wave-particle duality?

Made up of waves of pure energy while other times it can behave like it is made of small particles

Define wavelength:

Distance from one peak to the next

1 A =

10^-8 cm or 10^-10 m

Dwayne-Hunt Law:

Equation that allows the calculation of the minimum wavelength of an x-ray photon

Define frequency:

Number of alternations or disturbances per second

SI unit for frequency

Hertz (Hz)

What is the relationship between wavelength and frequency?

Inversely proportional

What is the range of frequency of all EM waves?

10^2 Hz to 10^24 Hz

How is energy measured?

Joules or electron volts (eV)

1 eV =

1.60 x 10^-19 Joules

Diffraction x-ray:

-Have energies below 10 keV

- Used for research, analysis, and non-destructive testing

What can be determined with diffraction x-rays?

Crystalline structure

What does x-ray crystallography show?

Arrangement of water molecules in ice, revealing the hydrogen bonds that hold the solid together

Grenz ray:

-Have energies between 10 and 18 keV

- Can be used in dermatology and forensic science

What are Grenz ray also known as?

Bucky rays

Diagnostic x-rays:

- Range from 20 keV and 150 keV

- Used for making diagnostic radiographs and CT scans

Superficial x-rays:

- Range from 50 keV and 110 keV

- Type of radiation used for a treatment of cancer (skin cancer)

Orthovoltage x-rays:

- Range from 150 keV and 300 keV

- Used for treatment of tumors within a few centimeters below the skin

Supervoltage x-rays:

- Range from 300 keV and 1000 keV

- Used for radiation therapy for tumors within 10 cm of the skin (usually head and neck cancers)

Megavoltage x-rays:

- Range above 1000 keV or 1 MeV

- Used for treating deep seeded tumors in the body and are created by a linear accelerator

What are the 12 properties of x-rays?

1. X-rays are Highly penetrating and invisible

2. X-rays are Electrically and magnetically neutral

3. X-rays are heterogenous or polyenergetic

4. X-rays produce little or no heat while interacting with matter

5. X-rays travel in straight lines and diverge from their source

6. X-rays travel at the speed of light in a vacuum

7. X-rays cannot be focused by an optical lens system

8. X-rays can cause the luminescence of certain crystals

9. X-rays can affect photographic film

10. X-rays can produce scatter when they come in contact with matter

11. X-rays can ionize matter

12. X-rays can cause chemical changes in matter and biological changes in living organisms

Why are X-rays invisible?

Because our eyes evolved to only see electromagnetic radiation in the visible light portion of the electromagnetic spectrum

When photons travel in a straight line and then diverge out from the source, what does it result in?

A decrease in their number as the distance from the origin is increased

The decrease follows what law?

Inverse square law

MKS unit

3 x 10^8 m/s

Visible light photons can undergo ______

Refraction

What is refraction?

Change in velocity as photons change the medium in which they travel

True or false

X-rays cannot be refracted

True

What is the most important property of X-rays?

X-rays can ionize matter