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Radiation Physics
Radiations Physics-Chapter 2
57
Anthropology
3rd Grade
09/26/2012

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Cards

Term
What happens to the strength of orbits as they get closer to the nucleus?
Definition
The closer the shell is to the nucleus, the stronger it is
Term
Radioactivity
Definition
unstable atoms undergo spontaneous disintergration(radioactive decay) to become more balanced
Term
Do we use radioactivity in dentistry?
Definition
NO
Term
Ionizing radiaion
Definition
capable of producing ions,radiation must have energy greater than electron bonding energy
Term
What two groups is radiation classified in?
Definition
1.Particulate radiation
2.Electromagnectic radiation
Term
Which type of ionizing radiation do we use?
Definition
Electromagnectic radiation
Term
Particulate Radiation
Definition
tiny particles of matter that have mass and travel in straight lines at high speeds
Term
Four types of particulate radiation
Definition
1.Alpha
2.Electron (beta & cathode)
3.Proton
4.Neutron
Term
What is one patrticulate radiation used in radiology?
Definition
Cathode rays, negative, originate in the xray tube
Term
Electromagnectic Radiation
Definition
Transmission of wave like energy(no mass) through space or matter
Term
How do electromagnectic radio waves come about?
Definition
Man made or naturally occur
Term
What is the electromagnectic Spectrum?
Definition
Electromagnectic radiation arranged accoridng to energy, classisifed as ionizing or non ionizing based on energy levels, only high energy radiation is capable of ionizing radiation
Term
High energy/ionizing radiation on the electromagnetic spectrum
Definition
1.Xrays and gamma rays (rasiothearpy, dentlal radiographs)
2.ultraviolet rays(sun)
Term
Low energy/nonionizing radiation
Definition
1.visible light
2.infraed rays
3.radio waves
photography, microwave, radar, television, radio
Term
How does electromagnectic radiation move through space?
Definition
as waves or particles
Term
particle
Definition
bundle of energy, photons, no mass or weight, traves as waves as speed of light, moves in straight line
Term
wave
Definition
characterized by velocity(speed) of wave, wavelength(distance of one crest to another), and frequency(number)of wavelengths at a given time
Term
How are electrons maintained in their orbits?
Definition
by electrostatic force between the positive nucleus and negative electrons
Term
How is binding energy determined?
Definition
By the distance between the nucleus and the orbiting electron

Closer=Stronger
Term
Molecule
Definition
Two or more atoms joined together by chemical bonds
Term
What are the two ways in which molecules are formed?
Definition
1.The transfer of electrons
2.The sharing of electrons
Term
An atom in a neutral state has equal..
Definition
protons and electrons
Term
Electronically unbalanced atoms?
Definition
an atoms with an incomplete outer shell, will attempt to capture an electron from another atom
Term
Ionization
Definition
the process in which atoms are converted to ions- the production of ions
Term
An atom that gaines or loses an electron becomes what? What is it then called?
Definition
electrically unbalanced, called an ion
Term
If an atom gaines an electron is gets a ? charge
Definition
negative
Term
What is an ion pair?
Definition
A negative ion(ejected electron) + a positive ion(atom)
Term
How do you get an ion pair?
Definition
energy from xray romoves an orbital electron from an atom
Term
Do xrays have mass, weight, or charge? Csn you see them? How fast do they travel?
Definition
No, no, no, no, at the speed of light
Term
What can xrays penetrate?
Definition
liquids, solids, gases
Term
tubehead seal
Definition
permits exit of xrays, seals oil, filters xray beam
Term
transformer
Definition
alters voltage of incoming electricity
Term
Aluminum disks
Definition
filter out long wavelengths
Term
Lead colluminater
Definition
restricts size of x-ray beam
Term
PID(position indicating device
Definition
aims and shapes x-ray beam
Term
What is the x-ray tube made of and how big is it?
Definition
leaded-glass housing, several inches long by 1 inch diameter
Term
What does the window in the xray tube do?
Definition
permits the x-ray beam to exit the tube and directs it towards the alluminum disks, lead colluminater, and PID
Term
Cathode
Definition
negative, supplies electrons, has tungsten filament, and molybdenum cup
Term
What is the molybdenum cup
Definition
focuses electrons into narrow beam and directs beam towards tungsten target
Term
What does the tungsten filament do?
Definition
produces electrons when heated
Term
What happens in the anode?
Definition
elextrons get converted to photons
Term
What does the tungsten target do?
Definition
focal spot, converts electons to photons
Term
What does the copper stem do?
Definition
scatters heat away from tungsten target
Term
Electricity
Definition
energy used to make xrays
Term
Direct current(DC)
Definition
when electrons flow in one direction through a conductor
Term
Alternating current(AC)
Definition
when electrons flow in two, opposite directions
Term
Rectification(dental xray tube)
Definition
-the conversion of AC current to DC current
-x ray tube acts this way assuring that current is always flowing in one direction
Term
Amperage
Definition
-takes place in cathode
-the number of electrons moving through a conductor
-current is measured in amperage or mA
Term
Voltage
Definition
-measurement of electronical force that causes electrons to move from a negative to positive pole
-measured in v or kV
Term
circuit
Definition
path of electrical current
Term
Filament circuit
Definition
-uses 3-5 volts
-regulates flow of electrical current to the tungsten filament
-controlled by mA settings
Term
High voltage circuit
Definition
-uses 65,000-100,000 volts
-provides hight voltage required to generate x-rays
-controlled by kV setting
Term
Transformer
Definition
device used to either increase or decrease voltage in electrical circuit
Term
What are the three transformers used to adjust the electrical circuit in the production of dental xray?
Definition
1.step up transformer
2.step down transformer
3.auto transformer
Term
Step down transformer
Definition
decrease voltage from the incoming 110- or 220- line voltage to the 3-5 volts used by filament curcuit
Term
Step up transformer
Definition
increases incoming voltage to 65,000 to 100,000 volts used in high voltage circuit
Term
Autotransformer
Definition
-a voltage compensator
-corrects minor fluctuations int he circuit
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