Fall NM: physics

what is physics

the study of matter, energy, and of the properties forces and interaction that influence the behavior of matter

what is radiation

the motion of energy through space

why is physics important to nuclear medicine

• radiactive decay

• interaction between matter and radiation

• detection and measurment of quantities of radiation and radiation protection

fluctuating feilds of electric and magnetic energy

electromagnetic waves

the speed of an electromagnetic wave in a vacuum is

• also known as ©

3.00 × 10⁸ m/s

c (velocity of light constant in m/s) = ?

λ (wavelength in m) x ν (frequency in 1/s)

E (energy) =

h (planck’s constant) x ν (frequency 1/s)

subsitution for E= hν

E=hc/ν

how would energy and frequency differ with a longer wavelength

lower frequency and less energy (radio and heat)

how would energy and frequency differ with a shorter wavelength

higher frequency and higher energy (gamma rays and x-rays)

how does radiation behave

wave- particle duality

how should we think of electromagnetic radiation

Photons which are chargelss bundlesof energy that travel at the speed of light or ( c)

which is matter

anything that occupies space and has a mass

which is atom

the smallest quantity of an element that retains all of the chemical properties of that element

can atoms be broke down into smaller particles without losing chemical properties

no

• father of modern atomic thought

• “Infinitesimally small pieces are indivisible (atomos - indivisible)”

• had their idea rejected by Aristotle (overlooked form 2,000 years)

Democritus

• rejected Democritus's idea

• “ you can cut a form of matter in half”

• believed all substances consist of four elements (air, earth, water, and fire)

Aristotle

• First atomic theory

  • atoms are tiny invisible particles

  • atoms of one element are all the same

  • atoms of different elements are different

  • compounds form by combining atoms

  • chemical reaction occur when atoms are sperated, joined, or rearranged

• viewed atoms as tiny solid spheres (organized by atomic wt)

John Dalton

• discovered atoms have electrical nature to structure and atom (electron)

• plum pudding model/ raisin bun model (atoms are mostly pos charged w/ electrons throughout)

J.J. Thomson

• gold fil experiment discovered protons and nucleus

• atoms are positive in the center (nucleus)and mostly composed of empty space

Ernest Rutherford

Gold foil experiment

proved that atoms are mostly empty space with a tiny, dense, positively charged nucleus at their center by having radioactive material emits beam of pos. alpha particles → hits gold foil → most particles went right through → some particles are deflected

• proposed that electrons move around the nucleus in specific layers or shells

  • expanded on rutherfords model to include planck quantum theory

  • electrons furthest away from nucleus had highest energy

  • electrons can jump by absorbing energy

Niels Bohr

• described the likelihood of finding electron in certain position using math equations

  • electrons dont move in orbits they move in waves

Erwin Schrodinger

• discovered particles with no charge

  • neutrons found in the nucleus

James chadwick

what theory proposed that electrons moving around the nucelus in a cloud (impossible to know where an electron is at a given time)

Modern theory

what are the three fundamental particles

1. protons

2. neutrons

3. electrons

• quarks held together by gluons

• (+) charge

• massive and centrally located in the nucleus

protons

• quarks held together by gluons

• neutral charge

• massive and centrally located in the nucleus

neutrons

• (-) charge

• revolve around the nucleus

• held in orbit by binding energy

electrons

which fundamental particle has this charge and mass..

• charge: -1.6 × 10^-19 coulombs

• mass: 9.1 × 10^-28g

electrons

which fundamental particle has this charge and mass..

• charge: +1.6 × 10^-19 coulombs

• mass: 1.67 × 10^-24g

protons

which fundamental particle has this charge and mass..

• charge:

• mass: 1.00898 amu (slightly heavier than a proton

neutrons

How many protons are there

• Total number of protons in the atom is the atomic number

8 (z)

how many neutrons are there

• atomic mass- atomic number

16-8= 8

how many electrons are there

• electrically neutral atom has an equal number of protons and electrons

8(z)

how many nucleons are there

• = to mass number

16

what is this describing

• dense, massive, very small compared to atom size

nucleus

Neutrons are unstable particles and break down into simpler, more stable particles of a proton, and electron and a neutrino – this instability of the neutron is the source

of one type of radioactive decay

what is this describing

• empty space, arrangment determines how atoms react chemically

• max number of electrons in any shell

electron orbits

max # of electrons in any shell (2n²)

• k=

• innermost and has greatest binding energy with n=1

1

max # of electrons in any shell (2n²)

• L=

2

max # of electrons in any shell (2n²)

• M=

3

how are electrons arranged

the number of electrons in the outermost shell of an atom is equal to its group in the periodic table while the number of the outermost electron shell of an atom is equal to its period in the periodic table

nuclear stability in the first 20 elements

Neutron (1): Proton (1)

nuclear stability for elements greater than 20

1:6:1

what determines the stability of nucleus

by the binding energy of the nucleons in addition to the number and configuration of the proton to neutron ratio

some nuclei hold additional energy in a nearly stable or metastable state causing the nucleus to emit the extra energy in the form of EM radiation

Isomeric transition

what is the eqaution for mass - energy relationship

• matter → energy → creates matter ( rest rest mass of a particle of matter)

• rest mass of a fundamental particle (g) → to energy using this equation

E=mc²

mass defect

atomic mass unit(amu) is equivalent to 1/12 the mass of a carbon 12 atom

in a mass defect how can particles be removed from the atom

by expanding a force greater than binding energy $

what nuclear family is this

• Atoms that have the same atomic number but

  different atomic mass numbers

isotopes

what nuclear family is this

• Atomic nuclei that have the same atomic mass

  number but different atomic numbers

isobars

what nuclear family is this

• Atoms that have the same number of neutrons but

  different numbers of protons

isotone

what nuclear family is this

• Having the same elements and different atomic

  mass number

isomer

what are molecules

atoms of various elements combined (ex. water H₂O and table salt NaCl)

what is a compound

a quantity of one type of molecule

nuclide

any configuration of protons and neutron forming an atom

nuclear instability is the basis for the process called

radioactive decay

when individual atoms undergo spontaneuos transformation to release energy they form

daughter nuclei

T or F: there is a way of predicting when the transformation will occur for a specific atom

false

how do radionuclide (unstable nuclides) reach stability

through the process of radioactive decay where nucleons will rearrange themselves to establish a mores stable configuration

a type of decay o radionuclide undergoes depends on what

• mass

• neutron: proton ratio

• energy

• very large unstable atom with high atomic mass may split into nuclear fragments

• smallest stable nuclear fragment that is emitted is an alpha paticle

Alpha decay

alpha particle = helium particle=

2 protons +2 neutrons

• nucleus of an unstable atom may break into larger fragments

• along with the larger fragments 2 or 3 neutrons and heat are emitted

fission

nuclei w/ excess nuetrons can achieve stability by a process that amounts to the conversion of a neutron into a proton, electron, antineutrino and energy

• protons remain in the nucleus

beta decay

beta decay

• electron emitted

free electron unitl it find a vacancy in an electron shell either in the atom of its origin or in another atom

beta decay

• antineutrino

conversation of energy and momentum. no electrical charge and a mass of almost zero

transmutation

the formation of a different element by a radioactive decay process

when an atomic number is increased by 1 it makes

a new element

T or F: electrons can recieve more of the energy and the antineutrino receives less, or vice

versa

True as a result the energy of the neta particle varies in a continuous energy spectrum with some max energy

average energy of a beta particle is ??? the max energy

1/3

Nuclei with excess protons can achieve stability by a process that amounts to the conversion of a proton into a neutron and a positron, a neutrino, and energy

• Neutron remains in nucleus

Positron Decay (PET used)

positron decay

• positron

undergoes collisions with surrounding matter losing energy and eventually will almost always annihilate with an electron in matter

positron decay

• neutrino

conversion of energy – massless with no electrical

how does positron loose kinetic energy

through collisions with surrounding matter and then eventually moves slow slow enough to be attracted to an electron

T or F: The positron and electron spiral toward each other forming a temporary

positronium before undergoing annihilation. The mass of the positron and electron is

converted into pure electron magnetic energy. 2 annihilation photons

true

Atomic number is decreased by 1 makes

a new element

Electron capture

occurs when an orbital electron travels in the proximity of the nucleus and is captured and combined with a proton to form a neutron.

Proton rich nuclei can also decay by

Electron Capture

these are characteristics of …

• Occurs in atoms that have electron vacancies in their inner shells

• Electrons drop down to fill inner shells from outer obits and release electromagnetic energy.

• The emission of energy is characteristic of the energy difference between shells.

• Electrons filling the K shell are more energetic than those that fill an L shell because of the proximity to the nucleus and the higher binding energy

X-rays

creation of this is an alternative to characteristics of x-rays

auger electrons

auger electrons

surplus energy is given to another orbital electron which is ejected

what is the result of auger electrons

the atom is left with two vacancies in the electron structure which can lead to emission of charactersitics x-rays or secondary auger electrons

what emission can be apart of another decay process and usually occurs when there is more than 100keV of excess energy in the excited nucleus

gamma emission

The ideal radionuclides for nuclear medicine are those that emit

only gamma rays without emitting particulate radiation

An alternative process to gamma-ray emission in metastable nuclei where Transfer of energy from the nucleus to an orbital electron, which is then ejected from the atom

internal conversion

in a diagram representing a decay scheme where is the atomic number (z)

Horizontal (bottom) axis

in a diagram representing a decay scheme where is the energy of the nucleus

Vertical (up) axis

Arrows to the left show…

decrease in atomic number(z)

Arrows to the right mean….

increase in atomic number(z)

arrows that point straight down mean

no change in atomic number

this shows the placement of a daughter relative to parent nuclide

• which type of radiation is this

Alpha

this shows the placement of a daughter relative to parent nuclide

• which type of radiation is this

beta (-)

this shows the placement of a daughter relative to parent nuclide

• which type of radiation is this

Beta (+)

this shows the placement of a daughter relative to parent nuclide

• which type of radiation is this

electron capture

this shows the placement of a daughter relative to parent nuclide

• which type of radiation is this

gamma emission

label excitation or ionization

• Process of absorbing small

  amounts of energy temporarily in

  the electron structure of an atom

excitation

label excitation or ionization

• Energy must be larger than the

  binding energy of the particular

  orbital electron

ionization

label excitation or ionization

• Removal of outer electron

ionization