EXAM Q AND A STUDY GUIDE
◉ Excitation
Answer: -an orbital electron receives energy less than its binding
energy and is promoted to a higher energy level
-the electron will eventually fall back to its original energy level
emitting some characteristic energy
-not enough energy it given to the electron to remove it so it will just
move up to a different energy level, but then fall back to its original
energy level and emit that excess energy in the form of characteristic
radiation, will emit the difference between the energy shells
◉ ionization
Answer: -an orbital electron receives energy in excess of its binding
energy
-the electron is ejected with KE equal to the incident particle or
photon energy
-binding energy
-the electron is going to come off of the atom, you will still have
cascading secondary radiation being given off because other
,electrons are falling into different shells to fill the space of the
emitted electron
-this is how an ion pair is created
-if you have an electron shell that is of 100 keV, and it is interacted
with by a photon of 130 keV, it will take 100 keV to emit it from its
shell and the residual 30 keV is the energy is will have left over to
continue in motion outside of the atom (30 keV left over in the form
of KE)
◉ bremsstrahlung
Answer: nucleus is positively charged, so if a beta particle misses the
electron it will head toward the nucleus
-that beta is attracted to the positive nucleus, but it does not have
enough energy to get into the nucleus, that beta particle will them
get slung around the nucleus
-this interaction is still a magnetic field interaction, so that means
there is energy being traded between the beta and the nucleus, the
outgoing energy of the beta is less than it came in with, because it
gave some energy to the nucleus in order for it to go around it
-the nucleus changed the velocity and direction of the beta particle
-the energy given to the nucleus has to be emitted somehow,
because the nucleus is already stable and doesn't want excess
energy. the nucleus will give off that energy as an x-ray
, -no physical interaction , except for the magnetic field of the electron
being slung around the nucleus
-electron will change direction due to nucleus
◉ true or false, alpha particle are great for imaging
Answer: false, alpha particles are not good for imaging
-alphas will maybe produce some weak gammas or bremsstrahlung,
but it will not look very nice
◉ what are 3 types of γ/x interactions
Answer: -Pair production
-compton scatter
-photoelectric effect
◉ pair production
Answer: a photon that is >than 1.02 MeV (commonly >1.5 MeV) will
come in close proximity to a heavy nucleus. it will then
spontaneously decay into an electron and a positron. the positron
will then go on to do positron stuff (annihilate with an electron and
give off 2 photons of 0.511 keV each)