Xray Tube

Question 1

• main components of xray machines

Answer 1

1. control console
2. high-voltage section
3. xray tube

Question 2

• produces xray
• 2 electrodes : anode, cathod
• evacuated glass bulb with positive and negative electrodes

Answer 2

Xray Tube

Question 3

External Components

Answer 3

1. protective housing
2. glass / metal enclosure
3. support system

Question 4

• guards against excessive radiation exposure
• protect against accidental electric shock
• provides mechanical support

Answer 4

Protective Housing

Question 5

• spreads everywhere, equal in all directions

Answer 5

Isotopic

Question 6

• reduces the identity of leakage of radiation

Answer 6

1 milligrate at a distance of 1 meter from the surface

Question 7

• maintains vacuum inside the tube
• early xray - crookes - not vacuum
• modern xray - coolidge - vacuum

Answer 7

Metal / Glass Enclosure

Question 8

• glass enclosure is relatively large ___

Answer 8

30-50 cm long, 20cm in diameter

Question 9

• it can withstand heat
• “boro silicate”

Answer 9

Pyrex

Question 10

• tube failure

Answer 10

Tube Arcing

Question 11

Internal Components

Answer 11

1. Cathode
2. Anode

Question 12

• negative side of the tube
• filament and focusing cup

Answer 12

Cathode

Question 13

• produces a thermionic cloud (electrons)
• accelerates the e- towards the anode
• focuses the electron stream

Answer 13

Focusing Cup

Question 14

• small coilf of thin thoriated tungsten wire
• 0.1-.02mm thick ; 1-2cm long ; 2mm diameter
• when heated, emits electron

Answer 14

Filament

Question 15

• outer shell electrons of the filament atoms are “boiled off” and ejected from the filament

Answer 15

Thermionic Emission

Question 16

• enhance thermionic emission___

Answer 16

add 1-2% thorium

Question 17

• shallow depression in the cathode assembly designed to house the filament
• made of nickel purpose to narrow down the thermionic cloud
• negatively charged so it electrostatically confines the electron beam

Answer 17

Focusing Cup

Question 18

• positive side of the xray tube
  1. target surface for the high-voltage electrons from filament
  2. conducts high voltage from the cathode back to xray generator
  3. primary thermal conductor

Answer 18

Anode

Question 19

• high capacity xray tubes have___

Answer 19

molybdenum or graphite layers under tungsten target

Question 20

Tungsten 74

Answer 20

1. high atomic number
2. thermal conductivity
3. high melting point (3410°C)

Question 21

• stationary
• made up of copper
• mechanically supports tubgsten target
• removes het efficiently from the tungsten heart

Answer 21

Copper Block

Question 22

• rotational
• made of molybdenum
• reduce thermal conductivity

Answer 22

Anode Stem

Question 23

• rotating
• electromagnetic induction motor is used to turn the anode
• stator - part outside
• rotor - part inside

Answer 23

Induction Motor