Physics Chapter 6 Test Flashcards Preview

spring 2015 > Physics Chapter 6 Test > Flashcards

Flashcards in Physics Chapter 6 Test Deck (37):
1

Know the 2 ways filament electrons interact with target atoms to produce x-rays?

Characteristic interaction and bremsstrahlung interactions

2

How do characteristic photons get their name?

Their energy is "characteristic" or dependent on the difference in binding energy between the shells involved

3

Know why medical imaging generally focuses on the K shell

It has the highest energy and the most useful for imaging purposes

4

Know how you remove orbital electrons during characteristic interactions

the filament electron must have kinetic energy equal to or greater than the binding energy of the electron with which it interacts

5

Describe what happens during a bremsstrahlung interaction

A filament electron is attracted to the nucleus causing it to slow down and change direction. The energy loss is emitted as a bremsstrahlung photon

6

Know what the strength of the interaction depends on with a brems interaction

How close the filament electron passes to the nucleus

7

Know how to find the energy of a brems photon

Subtracting the energy that filament electron leaves the atom with from the energy it had upon entering

8

Know the 4 technical factors that affect beam quantity

mAs
KVP
Distance
Filtration

9

Know what you should always associate beam quantity with

Radiation dose

10

Know what is directionally proportional with beam quantity?

mAs

11

Know what is considered the primary controlling factor for beam quantity

mAs

12

Know how beam quantity varies

Square of the ratio of the change in kVp

13

Know what a 15% increase in kVp is equivalent to

Doubling the mAs

14

Be able to work a problem using the Inverse Square Law

I1/I2= D2^2/D1^2

15

Know how filtration affects beam quantity

Decreases

16

Know what it looks like on an image when photons reach the IR

dark shades of the image

17

Know what image looks like when no photons reach the IR

light or clear areas of the image

18

Know what affects beam quality

kVp and filtration

19

Know what the purpose filtration serves

To remove the lower-energy photons, making the average energy (quality) higher

20

Know how beam quality is measured

half value layer

21

Know how to find half value layer

First measuring the intensity of the beam with a radiation detector, then placing aluminum filters of known thickness between the tube and detector until the intensity reading is reduced to half the original value

22

Know the normal HVL range for general diagnostic beams

3-5 mmAC

23

Know how the characteristic photons are named (2)

for the shell being filled

24

Know why a brems photons energy depends on the strength of attraction

Because brems photons are the result of the filament electrons attraction to the nucleus

25

Know what the most common range of energy of a brems photon is

just above zero to max kVp

26

Know what shape a brems photon graph represents

bell shape

27

Know what the left and right side of the curve represents for a brems photon graph

left just above zero, right-touches the x axis at the kVp selected

28

know what the peak of a brems photon graph represents

one third of the kVp selected

29

On the emission spectrum changes in the following indicate:
a. y axis
b. X axis

Y Axis- changes in quantity
X axis- changes in quality

30

Know what the five factors are that change the appearance of the xray emission spectrum

mA, kVp, tube filtration, generator type, and target material

31

Know what changes in mA affect (include discrete line)

Affect beam quantity but has no affect on quality and does not change the position of the discrete line

32

Know what changes in kVp affect ( include the discrete line)

Affect beam quality and quantity but does not change the position of the discrete line

33

Know what tube filtration affects when all other factors remain the same

Decrease in Quantity
Increase in quality

34

Know what the changes in generator type can affect

Change the xray production efficiency

35

Know why high frequency generator units are used over single phase units

more efficient in producing xray than single phase units

36

Know what happens when a generator operates more efficiently

More filament electrons have the energy to produce xrays, increasing quantity (amplitude of curve)

37

Know what happens as the atomic number of the target material goes up

As it goes up, so does the average energy, quantity of photons, and the position of the discrete line of the spectrum.