Phyiscs: Matter And Radiation 3 (Huda)

Front 1

What is the origin of gamma rays

Back 1

nuclear process

Front 2

Are gamma rays high energy

Back 2

yes

Front 3

What is the the lowest energy of a nucleus called

Back 3

the ground state (most stable)

Front 4

Describe an excited state

Back 4

Excited states have increased energies, are unstable, and have a transient existence
before transforming into a more stable state.

Front 5

What is a metastable (isomeric) state

Back 5

Metastable states (isomeric states) are also unstable but have relatively long life-
times before transforming to another state.

Front 6

How long most the half life be to be considered metastable

Back 6

10^-12 seconds (small)

Front 7

What is the anotation of a metastable state

Back 7

The metastable state of an atom is denoted by a lower
case "m" after the mass number (e.g., technetium 99m).

Front 8

What happens when there is nuclear transformation to a more stable state

Back 8

release of energy in the form of gamma rays

Front 9

What is an isomeric transition

Back 9

both parent and daughter nuclei have the same mass
number, atomic number, and number of neutrons.

Front 10

What is another way that a nucleus can transfer energy

Back 10

-Rather than emitting gamma rays, energy may be transferred to an orbital electron,
which is then emitted from the atom as an internal conversion electron

Front 11

What are 4 types of decay modes

Back 11

Beta minus decay
Beta plus decay
alpha decay
electron capture
isomeric transition

Front 12

What is Beta minus decay

Back 12

a neutron inside the nucleus is converted into a proton

Front 13

How is the energy released when beta minus decay occurs

Back 13

excess energy is released as an energetic electron called a beta particle and an antineutrino

Front 14

Is a beta particle an energetic electron

Back 14

yes

Front 15

What is an antineutrino

Back 15

a entity that has no mass, no electric charge and rarely interacts with matter

Front 16

What 2 things realeased as a result of beta minus decay

Back 16

beta particle and antineutrino

Front 17

When does beta minus decay occur

Back 17

with too many neutrons

Front 18

What happens to the atomic number in beta minus decay

Back 18

I n β− decay, the atomic number increases by one, but the mass number remains
constant (remember a neutron converts to a proton thus increasing the atomic number).

Front 19

How much energy does the beta particle released during beta minus decay possess

Back 19

Th e beta particles (electrons) emitted during β− decay have a range of energies
(spectrum), up to a maximum energy (Ema x ).

Front 20

What are 2 ways to talk about the energy of a beta particle

Back 20

interms of average and maximu

Front 21

How much energy does a beta particle possess

Back 21

Th e average energy of beta emitters is approximately one third of the maximum

Front 22

What is an example of a beta emitter

Back 22

3 2 P is a pure beta emitter with a maximum beta particle energy of 1.71 MeV and
a mean beta particle energy of approximately 570 keV

Front 23

What is Beta plus decay

Back 23

-I n beta-plus (β + ) decay (sometimes called positron emission), a proton inside the
nucleus is converted into a neutron, and the excess energy is emitted as a positively
charged electron, called a positron, and a neutrino

Front 24

What is beta plus decay also known as

Back 24

positron emission

Front 25

What is converted in a beta positive decay

Back 25

proton to a neutron

Front 26

What is released during beta plus decay

Back 26

positron and neutrino

Front 27

What is a neutrino

Back 27

A neutrino has no electric charge, has no rest mass, and is similar to an antineu-trino.

Front 28

When does beta plus decay occur

Back 28

when a nuclei has too few neutrons

Front 29

What happens to the atomic number in beta plus decay

Back 29

-I n β+ decay, the atomic number decreases by one, and the mass number stays the
same

Front 30

What is a positron

Back 30

A positron is an electron with a positive charge instead of a negative charge and in-
teracts with matter like an electron.

Front 31

How do energetic positrons loss their energy

Back 31

by ionization and excitation of atomic electrons

Front 32

What happens to a positron once it loses its energy

Back 32

it annihilates with an electron

Front 33

How do positrons lose their energy

Back 33

Energetic positrons lose their energy by ionization and excitation of atomic elec-trons

Front 34

What is the energy possessed by a positron and a electron

Back 34

Th e mass (energy) of the positron and electron (511 keV each) is converted into
two 511 keV photons that are emitted 180 degrees apart.

Front 35

What happens when a positron and electron annihilate

Back 35

they releas photons 180 from each other

Front 36

What are examples of positron emitters

Back 36

Positron emitters generally have short half-lives (1 1 C, 20 minutes; 1 5 O, 2 minutes;
18F, 110 minutes).

Front 37

What is electron capture

Back 37

I n electron capture, a proton inside the nucleus is converted into a neutron by cap-turing an electron from one of the atomic shells (e.g., K, L, and M)

Front 38

What is emitted during electron capture

Back 38

a neutrino

Front 39

When does electron capture occur

Back 39

when there are too few neutrons or too many protons

Front 40

What happens to the mass and atomic number following electron capture

Back 40

I n electron capture, the atomic number decreases by one, and the mass number
stays the same.

Front 41

How is the excess energy emitted

Back 41

-Th e excess energy is emitted as a characteristic x-ray, or Auger electron.

Front 42

How much energy does the auger electron possess

Back 42

Th e energy of the Auger electron is equal to the characteristic x-ray energy mi-nus the electron binding energy.

Front 43

What does electron capture compete with

Back 43

B plus decay

Front 44

What are some atoms that undergo electron capture

Back 44

-Important electron capture radionuclides used in nuclear medicine include 5 7 Co,
6 7 Ga, 111In, 123I, 125I, and 201T1.

Front 45

What is alpha decay

Back 45

I n alpha decay, a radionuclide emits an alpha particle consisting of two neutrons
and two protons (i.e., helium nucleus).

Front 46

Are 2 neutrons and a proton released in alpha decay

Back 46

yes

Front 47

What atoms is alpha decay most common

Back 47

Alph a decay is most common in atoms with atomic numbers (Z) greater than 82

Front 48

A

Back 48

Mass

Front 49

Z

Back 49

atomic number (protons)

Front 50

Is radon an alpha emitter

Back 50

yes, 22 6 R a is a common alpha emitter found in nature, which decays to 22 2 Ra (radon),
which is another alpha emitter.

Front 51

What happens to the atomic number in alpha decay

Back 51

it decreases by 2 and the mass number by 2

Front 52

What is an alpha particle equivalent too

Back 52

a helium

Front 53

What is the energy of an alpha particle

Back 53

Alph a particles have an energy between 4 and 7 MeV

Front 54

How far do alpha particle travel

Back 54

-Alph a particles can travel from 1 to 10 cm in air, but less than 0.1 mm in tissue

Front 55

Are alpha particles dangerous

Back 55

Alph a particles can travel from 1 to 10 cm in air, but less than 0.1 mm in tissue.
-Alph a particles thus pose little risk as an external radiation source but pose a high
risk if ingested or injected

Front 56

Summary of decay

Back 56