final definitions

Question 1

Thermal Neutrons

Answer 1

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

Question 2

Fast Neutrons

Answer 2

These neutrons cover the energy range from 10 keV upward

Question 3

Radiation Length

Answer 3

i.The mass thickness in which electron kinetic energy would be diminished to 1/e of its original value due to radiative interactions only

Question 4

Critical Energy

Answer 4

E=800/Z

Question 5

Neutron Spallation

Answer 5

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

Question 6

Mean Chord Length

Answer 6

L=4V/S

Question 7

Bragg Peak

Answer 7

Question 8

Slowing Down time

Answer 8

Question 9

Minimum Ionizing particle

Answer 9

A particle whose mean energy loss rate through matter is close to the minimum

Question 10

Cerenkov radiation

Answer 10

Question 11

Energy Straggling

Answer 11

• 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

Question 12

Range Straggling

Answer 12

Fluctuation of path length of individual particles of the same energy

Question 13

Synchrotron Radiation

Answer 13

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

Question 14

Impact Parameter

Answer 14

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

Question 15

Linear Stopping Power

Answer 15

Question 16

Critical Energy

Answer 16

Question 17

Mass Collision Stopping Power

Answer 17

Question 18

Shell Correction

Answer 18

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

Question 19

Delta rays

Answer 19

Any recoil particle caused by secondary ionization

Question 20

Beta Rays

Answer 20

high-energy, high-speed electrons or positrons emitted by certain types of radioactive nuclei

Question 21

Classical Radius of the Electron

Answer 21

Question 22

CSDA Range

Answer 22

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

Question 23

CPE

Answer 23

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.

Question 24

TCPE

Answer 24

TCPE is said to exist at all points within a region in which D~K_c , with the constant of proportionality > 1.

Question 25

Auger Electron

Answer 25

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.

Question 26

Restricted Mass Stopping Power

Answer 26