Week 4 Generation of beam Oral radiography

Control panel

kV - kilovoltage

mA - milliamperage

Exposure time

Exposure button

A. Extension Arm - long peice

b. yoke - moves the big box ( tubehead)

C. Tubehead - the box thats does the x-ray

d. power button

Parts of tubehead

Metal housing - housing the x-ray tubehead

Insulating oil- surrounds the x-ray tube + transformers prevent overheating by absorbing the head created by x-ray

Aluminum disk - filters out non-penetrating longer length wavelength x-ray

Lead collimator - restricts the size of the x-ray beam

PID- position indication cone

X-ray Tube - Cathode ( negative electrode)

Tungsten filaments - coiled wire made of tungsten produces electron when heated

Molybdenum focusing cup - focuses the electron into a narrow beam directs the beam across the tube towards the tungsten of the anode

Anode - positive electrode

Tungsten target - serves as a focal spot + converts bombarding electron into photon

Copper stem- dissipate heat away from the tungsten target

electricity

Energy used to make x-ray

Amperage (mA) - measurement of the amount of electron

Voltage (kVp) - measuring the force that causes the electron to move from cathode to the anode

Production of dental X-ray

Electricity from wall outlet supplies power- when machine is turned on current enter control panel → to tube head via electrical wires in extension arm

Current is directed to filament circuit and step-down transformer ( reduce voltage from 110 or 220 to 3-5 v)

Filament circuit heats the tungsten filament in the cathode → thermionic emission occurs ( release of electron from tungsten filament formation of electron cloud

Activation of exposure button causing electron to travel from cathode to anode

step-up transformer- 60,000 100,00 volts

Production of X-ray pt 2

Electron strike the tungsten target → x ray energy + heat → 1% is converted to x-ray

Heat carried away from copper stem + absorbed by insulating oil

x-ray emitted from target

x-ray travel through unleased glass window, tubehead seal + aluminum disk

size of beam restricted by collimator

conversion of electrons to x-ray photon

2 Mechanisms

1- General radiation

2- Characteristic radiation

General ( bremsstrahlung) radiation

Tungsten target atom

When an electron that passes close to the nucleus of a tungsten atom is slowed down, an x-ray photon of lower energy known as general radiation results

Aka: Braking radiation

speeding electrons slow down because of interaction w/ tungsten target at the anode

when electron comes close to nucleus of a tungsten atom it is attracted to the nucleus and slows down

results in an x-ray photon of lower energy

7-% of x-ray produced are this type