lecture 3 prod of xrays PART 2

Question 1

flow of electrons through an electrical conductor

Answer 1

electricity

Question 2

amount of electrons flowing through a conductor per second

Answer 2

current [measured in amperes A] [also called mA]

Question 3

path of electrical current

Answer 3

circuit

Question 4

difference in electrical potential energy between two points in an electric circuit.

Answer 4

voltage (potential difference) measured in volts V

Question 5

during each 1/2 cycle (1/120 of a second) anode is positive and

Answer 5

attracts the electrons from the cathode
[electricity]

Question 6

during each alternate 1/2 cycle (1/120 of a second) anode is negative, therefore,

Answer 6

no attraction for electrons exists and no x-radiation is produced (inverse voltage)

Question 7

in the USA ___ cycles of electricity per second

Answer 7

60

Question 8

changes alternating current into direct current

Answer 8

full wave rectification

Question 9

full wave rectification has ____ potential between cathode and anode.

Answer 9

constant potential

Question 10

full wave rectification has highest volt possible, so means more efficient ___ at producing x-rays and x-rays produced will have a ___energy

Answer 10

electrons
higher energy

Question 11

constant potential and direct current will have:
____exposure times
_____beam intensity
_____mean energy of beam
_____radiation dose

Answer 11

shorter exposure times
more consistent beam intensity
higher mean energy of beam
decreased radiation dose

Question 12

how are x-rays produced?

Answer 12

whenever high-speed electrons are suddenly decelerated or brought to stop when they pass close to nucleus of high Z # abosrobing material (tungsten)

Question 13

what are the 2 mechs for x-ray formation

Answer 13

bremsstrahlung radiation and characteristic radiation

Question 14

breaking radiation mech/ electron to nucleus for xray formation

Answer 14

bremsstrahlung radiation

Question 15

electron to electron interaction

Answer 15

characterisitic radiation

Question 16

mech where fast moving electrons either slow down or stop when they come close to the nucleus of the atoms and part of their energy is transferred as xrays

Answer 16

bremsstrahlung radiation

Question 17

mech when electrons displace inner shell electrons, this mech is produced

Answer 17

characterisitic radiation

Question 18

high-velocity electrons directed toward the target material

Answer 18

bramsstrahlung radiation

Question 19

with bramsstrahlung radiation, higher the velocity, the ____the KE of electrons.
bramsstrahlung radiation increases with _____ the voltage (kV) and the atomic number of the target

Answer 19

greater KE (higher velocity)
radiation increases with increasing voltage

Question 20

two types of bramsstrahlung radiation

Answer 20

1. impacting electron is deflected and decelerated. kinetic energy lost is emitted as an x-ray photon
2. head-on collision with nucleus: electron brought to rest producing a max energy photon

Question 21

this type of radiation has a wide distribution of wavelengths (heterogeneous)

Answer 21

bramsstrahlung radiation

Question 22

what happens when electrons interact with tungsten atoms during bramsstrahlung radiation?

Answer 22

electrons lose their energies in random fashion

Question 23

summerize bramsstrahlung radiation steps

Answer 23

1. electrons with different voltage are accelerated towards the anode under the influence of high kilovoltage
2. at anode, they either interact with nucleus or rapidly decelerate and get deflected (change direction)
3. process results in the release of energy in the form of x-ray photons (eV)

Question 24

this radiation arises when cathode electron collides with inner orbital electron of Tungsten atom (target) and removes it from orbit. then, the atom is now ____ and unstable

Answer 24

characterisitic radiation
atom is then ionized and unstable

Question 25

during characterisitic radiation, the hole left by the electron is:

Answer 25

filled by electron from outer shell, and energy is emitted from this electron in the form of x-ray radiation characterisitic of tungsten and the involved shell

Question 26

with characterisitic radiation, the energy emitted by the electron is equivalent to the difference in the binding energies of the

Answer 26

two shells/orbit

Question 27

with characteristic radiation, when an outer shell electron is shifted inward it must give up some of its energy in the form of radiaiton called

Answer 27

a characterisitic photon

Question 28

this radiation makes up the majority of the x-ray beam and produces a heterogenous beam of varying photon energies

Answer 28

bramsstrahlung radiation

Question 29

this radiaiton is only a minor source of radiation from the x-ray tube and produces photon energies specific for the target material

Answer 29

characteristic radiation