Travel wave guide – used in low energy systems to accelerate electrons

Standing wave guide – used in high energy systems to accelerate electrons

Microtron – a therapy machine that consists on one housing that can feed electrons to many treatment machines.  This type of system can produce any energy you want

Cyclotron – a therapy machine used to produce neutrons from an ion source of deuterons

Van de Graff generator – static electricity machine

Betatron – is a donut shaped therapy machine that produces high energy photons with dual energies.  Is not used because of its size which makes it a non-isocentric machine.

Cobalt 60 -  is produced by bombarding Cobalt 59 with slow neutron.  It is then used in a therapy machine to produce photons at energies of 1.13 Mev and 1.33 Mev (giving it the average energy of 1.25 Mev)

Roentgen - the unit of exposure is coulomb per kg of dry air and the special unit is the Roentgen (R)

Sensitive Volume – the measured amount of air (mass) that will be exposed to ionizing radiation between the 2 plates (it is extremely uniform in the middle / a well defined volume that we will collect charge from)

electronic equilibrium – the number of electrons lost is equal to the number of electrons gained

Thimble Chamber – can be used on a day to day basis in a department

Recombination region - At lower voltages electrons can recombine

Ionization region – the voltage at which you collect every electron that was liberated  (any further increase in voltage will not collect any more electrons)

Proportional region – kinetic energy is imparted to the electons that cause additional electrons to be liberated that is over the amount of electrons that would normally be freed by radiation

Limited Proportional region - kinetic energy is imparted to the electons that cause additional electrons to be liberated that is over the amount of electrons that would normally be freed by radiation

Geiger Mueller Region – ionizing events cause the gas volume to become ionized (basis for Geiger Counter which measures the smallest presence of radiation [survey meter])

Condenser ionization chamber – is a chamber where the charge is placed on a central wire by connecting the chamber to a electrometer and charging it up.  When the chamber is at a full charge it will read zero.  As the chamber is irradiated the wire begins to loose charge which will give us a reading.  Used to measure photons.

Pocket ionization chamber – same as a condenser ionization chamber only for personal use.

Baldwin – Farmer substandard dosimeter – is a chamber used in radiation therapy depeartment where the  Chamber is connected by a coaxial cable to an electrometer and the reading are taken while the machine is on from outside the room.

Parallel plate chamber (pancake chamber) – chamber that is placed inside a plastic block with a window.  This window allows for measurements just above the skin surface.

Cutie Pie – is a portable survey meter that is used to measure fields that are larger than 1mR/h

Gieger Counter – is a survey meter than is used to measure exposure of less than 100mR/h.

TLD (thermo luminescent dosimeter) – Litihum fluoride is radiated and then placed in an oven to see how much light it emits.  The amount of light it emits is then asscoited with a dose.

Osl Optically Stimulating Luminescence - Principle that OSL’s work on is the same as TLD’s.  Crystals trap and store energy from the exposure to ionizing radiation.  We then shine a green laser on the crystal and measure the intensity of blue light emitted

Diodes - Made From Semiconductors (Crystalline Silicon).  Diode Has An Appropriate Buildup Cap Built Onto It.  In The Radiation Field The Overall Significant Effect In The Diode Is The Production Of Many Electron Hole Pairs Along The Track Of The Ionizing Particle

Luminescence – any material that emits light in response to an outside stimulation (ionizing radiation)

Photocathode - is adevice that emits electrons when illuminated by light in a process called photoemmision

Dynodes - amplify the electron coming from the photocathode by the emission of secondary electrons

Coherent Scatter - With coherent scattering the incident photon interacts with the electron or electron cloud in the atom, in such a way that the they will oscillate (that is vibrate) at the same frequency as the incident electromagnetic wave.  Then the electron or electron cloud will reradiate the energy at the same frequency

Photoelectric Effect - It was found both experimentally and theoretically that 80% of the photoelectric absorption processes takes place in the K shell,  photon must first have an energy equal to or greater than the binding energy of electron in the atom.  The incident photon must be completely absorbed by the electron.  The electron is then ejected from the atom.  The excess energy over the binding energy is given to the electron in the form of kinetic energy (which is the speed of the electron).  The hole left in the atom is now filled by an outer shell electron or a free electron with the emission of characteristic radiation.

Compton Interaction -  a photon interacts with a “free” or outer shell electron.  A portion of the incident energy of the photon will be transferred to an electron in the form of kinetic energy.  The incident photon now called scatter photon will be deflected in a new direction with less energy.

Pair Production - Photon interacts with the nuclear field of the atom (and then decides that its not going to be a photons anymore :

Electron (negatron)  - goes on to produce ionizations, exitations, and Brehmstraahlung

Positive electron (positron) – goes on to produce ionizations, exitations, and Brehmstraahlung until it looses all its energy.  But since its postive in a sea of negative it decides not to be matter anymore and becomes 2 photons (.511 Mev each traveling at 180 degrees apart).These 2 photons are also know as Annihilation Radiation.