final definitions Flashcards
Thermal Neutrons
Any free neutron that has an average kinetic energy corresponding to the average energy of the particles of the ambient materials. Their most probable kinetic energy is 0.025 eV
Fast Neutrons
These neutrons cover the energy range from 10 keV upward
Radiation Length
i.The mass thickness in which electron kinetic energy would be diminished to 1/e of its original value due to radiative interactions only
Critical Energy
E=800/Z
Neutron Spallation
i.Spallation occurs when a fast neutron n penetrates the nucleus and adds sufficient energy to the nucleus so that is disintegrates into many small residual components such as alpha and protons
Mean Chord Length
L=4V/S
Bragg Peak
Slowing Down time
Minimum Ionizing particle
A particle whose mean energy loss rate through matter is close to the minimum
Cerenkov radiation
Energy Straggling
- The energy loss by a heavy charged particle collision in a medium is a statistical or stochastic process
- When a monoenergetic beam of particles pass through a medium, a spread of energies results around the averages as it passes a given depth
- This unequal energy loss for a beam of similar condition is called energy straggling
Range Straggling
Fluctuation of path length of individual particles of the same energy
Synchrotron Radiation
Synchrotron Radiation is the name given to the radiation which occurs when charged particles are accelerated in a curved path or orbit. Classically, any charged particle which moves in a curved path or is accelerated in a straight-line path will emit electromagnetic radiation
Impact Parameter
Is defined as the perpendicular distance between the path of a projectile and the center of the field created by an object that the projectile is approaching
Linear Stopping Power
Critical Energy
Mass Collision Stopping Power
Shell Correction
The original approximation assumed that the passing particle had a velocity much greater than that of the atomic electrons. However, this is not always the case. At certain velocities, the K-shell electrons could be moving faster than the passing particle meaning they do not contribute to collision stopping power
Delta rays
Any recoil particle caused by secondary ionization
Beta Rays
high-energy, high-speed electrons or positrons emitted by certain types of radioactive nuclei
Classical Radius of the Electron
CSDA Range
very close approximation to the average path length traveled by a charged particle as it slows down to rest, calculated in the continuous-slowing-down approximation. In this approximation, the rate of energy loss at every point along the track is assumed to be equal to the same as the total stopping power. Energy-loss fluctuations are neglected. The CSDA range is obtained by integrating the reciprocal of the total stopping power with respect to energy
CPE
occurs when the number of charged particles leaving a volume is equal to the number entering, for each energy and type of particle. When CPE exists in an irradiated medium, the absorbed dose in the volume is equal to the collision kerma.
TCPE
TCPE is said to exist at all points within a region in which D~K_c , with the constant of proportionality > 1.
Auger Electron
The Auger effect is a physical phenomenon in which the filling of an inner-shell vacancy of an atom is accompanied by the emission of an electron from the same atom. When a core electron is removed, leaving a vacancy, an electron from a higher energy level may fall into the vacancy, resulting in a release of energy.
Restricted Mass Stopping Power
