Radiation Physics Test 2

Front 1

What causes an atom to be unstable or radioactive?

Back 1

having neutron to proton ratio that is either too low or too high

Front 2

Isotopes have the same?
and different?

Back 2

same atomic number
different mass
different number of neutrons

Front 3

Isotones have the same?
and different?

Back 3

same number of neutrons
different atomic number
different mass

Front 4

Isobars have the same?
and different?

Back 4

Same mass
Different atomic number
Different number of neutrons

Front 5

Isomers have the same?
and different?

Back 5

SAME atomic number, mass, and number of neutrons

Front 6

What is a beta particle?

Back 6

an electron that comes out of the nucleus

Front 7

Does atomic mass include electrons?

Back 7

YES

Front 8

How does a Beta particle's mass compare with the mass of a proton or neutron?

Back 8

it is about 1,800 times smaller

Front 9

What is transmutation?

Back 9

Changing from one element to another

Front 10

What is a decay chain?

Back 10

when 1 radioactive element changes into another radioactive element and so on

Front 11

What is disintegration?

Back 11

when a nuclide emits a charged particle

Front 12

The basic unit for radioactivity is measured in?

Back 12

Disintegration per unit time
DPS
(this is the SI unit)

Front 13

The Curie is a unit for what?

Back 13

radioactivity

Front 14

What is the abbreviation for Curie?

Back 14

Ci

Front 15

1 Ci= ? DPS

Back 15

3.7 X 10^10 DPS

Front 16

1 Bq = ? DPS

Back 16

1 Bq = 1 DPS

Front 17

1 Ci = ? Bq

Back 17

1 Ci= 3.7 X 10^10 Bq

Front 18

The Curie, Becquerel, and Disintegrations per second are all units of ?

Back 18

radioactivity

Front 19

Cps stands for? and is a unit of?

Back 19

Counts Per Second, and is NOT a measurement of radioactivity, it IS just a measurement

Front 20

What is the equation for decay constant?

Back 20

The symbol for decay constant is lambda
the equation is:
lambda= 0.693/half life
** make sure half life is in seconds?

Front 21

What is a half life?

Back 21

the time it takes for 50% of the ACTIVITY to decay

Front 22

What type of curve is the activity curve for half life?

Back 22

Exponential, therefore in theory you never get to 0 activity. However, the half life only works if you have enough atoms to still be predictable

Front 23

What is the formula for activity?

Back 23

A = lambda X n
A=activity
lambda=decay constant (0.693/halflife)
n=number of atoms
**make sure half life is in seconds?

Front 24

As the decay constant gets SMALLER what happens to the amount of time for the half life?

Back 24

it gets BIGGER, half life and decay constant are INVERSELY PROPORTIONAL

Front 25

When lambda (decay constant) decreases, you need alot of ______ to make up for it

Back 25

you need alot of ATOMS to make up for it

Front 26

What is the decay formula?

Back 26

A = A(not) X e^-lambda(t)
t= time elapsed
**the units for half life and time elapsed must MATCH!

Front 27

When radioactivity is happening in the body it is called?

Back 27

biological

Front 28

Biological half life:

Back 28

the body gets rid of the radioactivity in a biological half life (also an exponential formula)

Front 29

Together the PHYSICAL decay and the BIOLOGICAL excretion are called?

Back 29

the EFFECTIVE HALF LIFE

Front 30

What is the symbol for effective half life?

Back 30

Teff

Front 31

what is the formula for effective half life?

Back 31

Teff = (T physical X T biological)/(T physical + T biological)

Front 32

When calculating the effective half life (Teff) you answer is going to be...?

Back 32

a little smaller than the smaller of the two half lives used in your equation
(answer will never be larger than the Tp or the Tb)

Front 33

secular equilibrium:

Back 33

the half life of the parent is much greater than the half life of the daughter
T 1/2 of the parent >> T 1/2 daughter

Front 34

In secular equilibrium you see what relationship between the half life of the daughter and that of the parent?

Back 34

the activity of the daughter

Front 35

Transient equilibrium:

Back 35

the activity of the parent is greater than that of the daughter (they are closer in half lives than in secular equilibrium)

Front 36

What is the relationship in TRANSIENT equilibrium between parent and daughter activity?

Back 36

activity of the daughter is building up and appears to decay with the half life of the parent

Front 37

alpha particles consist of what?

Back 37

2 protons and 2 neutrons (mass is about 4 amu) alpha particles have NO ELECTRONS

Front 38

what is the biggest type of particle?

Back 38

Alpha particle

Front 39

alpha particles occur when the neutron to proton ratio is too ______

Back 39

LOW

Front 40

all alpha emitters have an atomic number greater than _____?

Back 40

82, with one exception

Front 41

For an alpha particle, total energy released (Q) is?

Back 41

for an alpha:
Q=Mass p -mass d -mass alpha -(2)mass electron

Front 42

what is the mass of an electron?

Back 42

0.00055 amu

Front 43

1 amu = ? MeV?

Back 43

931 Mev

Front 44

What is the formula for the energy of an alpha particle?

Back 44

E alpha = Q/ (1+ [mass of the alpha/mass of the daughter)]

Front 45

the decay scheme of the alpha particle does what?

Back 45

goes down and to the left

Front 46

How does a beta particle relate to an electron?

Back 46

A beta particle is the same thing as an electron, but it originates from INSIDE the nucleus

Front 47

What is the charge of a beta particle?

Back 47

-1

Front 48

What is the mass of a beta particle?

Back 48

0.00055 amu

Front 49

When does a beta particle occur?

Back 49

when the neutron to proton ratio is too HIGH

Front 50

Does atomic mass include the mass of the electrons?
Does the mass NUMBER include the mass of electrons?

Back 50

Atomic mass includes electrons
Mass NUMBER does NOT include electrons

Front 51

Beta particles have a mass NUMBER of?

Back 51

ZERO

Front 52

Q for beta particles is?

Back 52

Q = M parent - M daughter **this gives you the answer in amu's so you might need to convert into Mev's

Front 53

Is there recoil on beta particles?
Is there recoil on alpha particles?

Back 53

No for beta
Yes for alpha

Front 54

Are beta particles monoenergetic?

Back 54

NO

Front 55

What is an antineutrino?

Back 55

An infinitely small mass that has no charge and has no biological effects

the symbol is v (same as for f

Front 56

What is the formula for average energy?

Back 56

E with a line over it = 1/3 E max

Front 57

Decay scheme for beta particles looks like?

Back 57

down and to the right

Front 58

What is a positron?

Back 58

positrons are positively charged beta particles (B+). They are antimatter, it only exists for a very short time in nature. They come from the nucleus, they have the same mass as a beta particle

Front 59

When is a positron emitted?

Back 59

When neutron to proton ratio is too LOW

Front 60

What is a positron?

Back 60

an electron with a positive charge

Front 61

What do positrons interact with?

Back 61

positrons start to interact with matter and lose it's energy, they collide with negatively charged electrons and explode

Front 62

When a positron collides with an electron what happens?

Back 62

all the mass gets converted to energy, this is called annihilation. When a positron and an electron collide this produces two 511 Kev photons at 180 degrees apart

Front 63

Which type of imaging device uses the positron and electron collision for imaging?

Back 63

the PET scan

Front 64

When does electron capture occur?

Back 64

when the neutron to proton ratio is too LOW

Front 65

Electron capture is also called?

Back 65

K capture

Front 66

How is an x ray produced?

Back 66

When an electron gets pulled from the K shell into the nucleus (electron capture) the hole is filled by an electron in the L shell, this gives off the x ray

Front 67

What are characteristic X rays?

Back 67

They are characteristic or specific to the element from which they are emitted

Front 68

alpha and beta particles give what type of radiation?

Back 68

particulate

Front 69

x rays give off what type of radiation?

Back 69

electromagnetic

Front 70

Electromagnetic radiation does what?

Back 70

has oscillating electromagnetic waves, and does NOT require a medium

Front 71

As we increase frequency what happens to the wavelength?

Back 71

the wavelength decreases, they are INVERSELY PROPORTIONAL

Front 72

Characteristic X rays are?

Back 72

monoenergetic, they have a distinct energy

Front 73

What is a photon?

Back 73

a packet or bundle of electromagnetic radiation energy, photons are "particulate like"

Front 74

Formula for the dual nature of light?

Back 74

E (in Joules) = hv
h = plancks constant
v=frequency

Front 75

Alpha particles are _____?

Back 75

Monoenergetic

Front 76

Speed of light (c) is?

Back 76

2.998 X 10^8 m/s

Front 77

Decay constant (lambda) =?

Back 77

0.693/ T1/2

Front 78

To find what fraction of the original activity remains when you have the number of half lives do?

Back 78

1/ 2^# of half lives

1 divided by 2^# of half lives

Front 79

When do characteristic X rays happen?

Back 79

when electrons move from outer shells to inner shells, they are MONOENERGETIC

Front 80

Bremsstrahlung means?

Back 80

breaking radiation (as in slowing it down) They are NOT MONOENERGETIC, they have a continuous energy distribution from the max energy of a beta particle on down

Front 81

Gamma rays are emitted from?

Back 81

excited nuclei, they have NOTHING to do with electrons

Front 82

Bremsstrahlung comes from?

Back 82

electrons through a medium or in matter, Bremsstrahlung is a type of X ray

Front 83

Bremsstrahlung happens when?

Back 83

When a negatively charged beta particle approaches the positively charged nucleus it has radial acceleration some of the energy will be converted to heat, and some will come off as an x ray--Bremsstrahlung X ray

Front 84

The fraction of the Energy (from incident particles) converted into X rays is ________ proportional to the atomic number of the medium through which it passes

Back 84

DIRECTLY

Front 85

NEVER use lead to shield _______?

Back 85

Particulate stuff, because that creates X rays, because it has a high atomic number

Front 86

low density=_____ atomic number
High density=_______ atomic number

Back 86

low density, low atomic number
high density, high atomic number

Front 87

An alternative to characteristic X rays are?

Back 87

the creation of Auger electrons, this happens when the energy is transferred to another orbital electron that results in that electron being kicked out (an Auger electron)

Front 88

Excitation energy normally comes out as a gamma ray, but what is the alternative?

Back 88

can instead be transferred to an orbital electron causing the orbital to be emitted called a CONVERSION ELECTRON

Front 89

Conversion electrons come from?
Auger electrons come from?

Back 89

Gamma
Characteristic X rays

Front 90

How does an ion get created?

Back 90

incident radiation interacts with an orbital electron and imparts sufficient energy to expel it from the atom, this creates an ion (makes a positive ion because it lost an electron)

Front 91

The electron kicked out when a positive ion is made is considered a what?

Back 91

negative ion

Front 92

Ion pairs are what?

Back 92

the positive ion (positive atom) with the negative ion (the kicked out electron)

Front 93

ionization potential

Back 93

the amount of energy required to remove the least tightly bound electron

Front 94

excitation

Back 94

raising the electrons to a higher electron energy but not enough to make them leave

Front 95

specific ionization

Back 95

the number of ion pairs formed per unit distance traveled by the incident radiation

Front 96

linear energy transfer (LET)

Back 96

the AVERAGE energy deposited per unit path length (distance) traveled by the incident radiation

Front 97

alpha particles are _____ LET

Back 97

they are HIGH LET, they lose their energy very fast
alpha particles are the biggest particles with 2 charges

Front 98

Beta particles have a _____ LET

Back 98

LOW let, they are small and lose their energy slowly, they have 1 charge

Front 99

How do alpha particles penetrate?

Back 99

alpha particles are the LEAST penetrating type of radiation, because they have a HIGH LET, their range in air is only several cm, in tissue they go 1X10^ - 4 cm

Front 100

how do beta particles penetrate?

Back 100

they have a max range in a material which is dependent on the energy of the beta particle

Front 101

Which kind of radiation is easily shielded?

Back 101

charged particles (alpha and beta) are easily shielded, we use a LOW density or LOW atomic number shields for charged particles

Front 102

gamma rays come from where?

Back 102

the nucleus

Front 103

X rays come from where?

Back 103

the movement of electrons

Front 104

Pair Production is?

Back 104

the direct conversion of electromagnetic radiation to mass

Front 105

an incident photon causes?

Back 105

as it approaches the nucleus its energy is converted to mass in the form of an electron and a positron

Front 106

The threshold for pair production is greater than ______?

Back 106

1.02 Mev

Front 107

If pair production occurs, then what happens?

Back 107

all the incident radiation is converted to 2 masses, and electron and a positron

Front 108

Compton Scattering

Back 108

has a photon interacting with an OUTER shell electron and you get a scattered photon and a kicked out electron

Front 109

Compton scattering--
Input:
Output:

Back 109

Input:moderate energy photon acting on an outer shell electron
Output: emitted electron and lower energy scattered photon

Front 110

Compton scattering has what energy?

Back 110

medium energy

Front 111

Photoelectric absorption:
Input:
Output:

Back 111

Input: low energy photon acting on an INNER shell electron
Output: electron emitted, NO scattered photon

Front 112

You use a ____ atomic number absorber to increase the likelihood of photoelectric absorption

Back 112

a HIGH atomic number absorber (like lead)

Front 113

Roentgen (R)

Back 113

exposure unit. exposure must be measured in AIR and we only measure GAMMA and X RAYS (only electromagnetic radiation) (NOT charged particles)

Front 114

rad (radiation absorbed dose)

Back 114

it is a measure of the energy deposited per unit MASS

Front 115

1 rad = _____ erg/gram

Back 115

1 rad=100erg/gram

Front 116

rad (radiation absorbed dose) are measured from?

Back 116

ANY type of radiation in ANYTHING

Front 117

1 gray=_____rad's?

Back 117

1 gray=100 rads

Front 118

why don't we use rads very much?

Back 118

it doesn't take into account the effects of different types of radiation (like alpha particles and beta particles have very different effects)

Front 119

rem means?

Back 119

Roentgen equivalent man

Front 120

what is an rem?

Back 120

a unit of EQUIVALENT DOSE
rems=rads X quality factor

Front 121

quality factor for alpha particles is?

Back 121

20

Front 122

the quality factor is 1 for which types of radiation?

Back 122

X ray, Gamma rays, and beta particles

Front 123

1 Sievert=____rem

Back 123

1 Sv=100 rem

Front 124

1 gray=?

Back 124

1 gray = 1J/kg = 100 rads

Front 125

the quality factor is?

Back 125

a radiation weighting factor