Interaction with matter

Question 1

An x‐ray beam that passes through a medium is likely to undergo

Answer 1

absorption, scatter, or penetration

Question 2

the process of removing of
electrons from the orbital of an atom

Answer 2

IONIZATION

Question 3

the process of temporary
removal of electrons from the orbital of an
atom or vibration of the electrons of the atom.

Answer 3

EXCITATION

Question 4

radiation that during
its passage through an object has been
deviated in direction.

Answer 4

SCATTER RADIATION

Question 5

radiation produced when an outer shell electron jumps into inner shell

Answer 5

CHARACTERISTIC RADIATION

Question 6

radiation produced when high speed of
electrons are suddenly stopped or
decelerated.

Answer 6

BREMSSTRAHLUNG RADIATION

Question 7

positively charged electron.

Answer 7

POSITRON

Question 8

distance between two
succeeding wave crests

Answer 8

WAVELENGTH

Question 9

• the incident photon interacts with a
  target atom, causing it to become
  excited
• the incident photon wavelength(λ)
  equals the excess energy photon
  wavelength(λ’)
• changes direction without a change in wavelength
• does not cause ionization, it only
  cause excitation
• the target atom releases the excess
  energy as secondary or scatter
  radiation
• it causes film fog
• it occurs below 10 keV

Answer 9

CLASSICAL OR COHERENT SCATTERING

Question 10

TYPES OF COHERENTS SCATTERING:

Answer 10

• THOMPSON SCATTERING
• RAYLEIGH SCATTERING

Question 11

a single electron is involved in the
interaction.

Answer 11

THOMPSON SCATTERING

Question 12

results from a cooperative interaction with all the electrons of an atom

Answer 12

RAYLEIGH SCATTERING

Question 13

• an interaction of x-ray with outer-shell
  electron that not only scatters the
  photon but reduces its energy and
  ionizes the atom as well
• produces secondary or scatter
  radiation
• causes film fog
• occurs in moderate energy x-rays.

Answer 13

COMPTON EFFECT/INCOHERENT
SCATTERING

Question 14

Compton effect yields three products:

Answer 14

1. an ion pair
2. a positive atom
3. a negative electron(recoil electron)

Question 15

• undergo ionizing interaction with inner
  shell electron of the target atom, so
  that the photon is not scattered but
  totally absorbed
• also called photon-absorption
  interaction
• can not occur unless the incident
  photon has energy equal to or greater
  then the electron binding energy of the
  atom

Answer 15

PHOTOELECTRIC EFFECT

Question 16

• it is the strength of attachment of
  electron to the nucleus
• the closer an electron is to the nucleus,
  the more tightly it is bound
• the greater the total no. of electrons in
  an atom, the more tightly each is
  bound
• it takes more energy to ionize a large
  atom than a small atom

Answer 16

ELECTRON BINDING ENERGY

Question 17

Photoelectric effect yields three products:

Answer 17

1. a characteristic radiation
2. a negative ion(photoelectron)
3. a positive ion(an atom deficient of
   one electron)

Question 18

• it occurs if an incident photon has
  sufficient energy and may escape
  interaction with the electron cloud and
  come close enough to the nucleus of
  the target atom to come under the
  influence of the nuclear
  force(electrostatic) field
• the interaction between the incident
  photon and the nuclear force field
  causes the photon to disappear and in
  its place appear two electrons, one
  positively charged called positron and
  one negatively charged(negatron)
• the incident photon must have an
  energy of at least 1.02 MeV

Answer 18

PAIR PRODUCTION

Question 19

• it occurs with high-energy photons
  which escape interaction with
  electrons(electron cloud) and the
  nuclear electrostatic field and be
  absorbed directly by the nucleus
• the nucleus is raised to an excited
  state and instantaneously emits a
  nucleon or other nuclear fragment
• it occurs with energy above 10 MeV

Answer 19

PHOTODISINTEGRATION

Question 20

used in positron emission tomography(PET) for nuclear imaging and therapy

Answer 20

Pair production

Question 21

because of its extremely high energy is utilized in treating cancer tumors

Answer 21

Photodisintegration