### Appendix: Significance of Calculated Quantities

**Collision stopping power**: average rate of energy loss per unit
path length, due to Coulomb collisions that result in the ionization and
excitation of atoms. For heavy charged particles, the collision stopping
power is often called *electronic stopping power*.
**Density-effect correction**: enters into the formula for the
collision stopping power and takes into account the reduction of the collision
stopping power due to the polarization of the medium by the incident
electron.

**Radiative stopping power**: average rate of energy loss per unit
path length due to collisions with atoms and atomic electrons in which
bremsstrahlung quanta are emitted. Important only for electrons.

**Nuclear stopping power**: average rate of energy loss per unit
path length due to the transfer of energy to recoiling atoms in elastic
collisions. Important only for heavy charged particles.

**Total stopping power**: for electrons, the sum of the collision
and radiative stopping powers; for protons and helium ions, the sum of
collision and nuclear stopping powers.

**CSDA range**: a 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 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.

**Projected range**: average value of the depth to which a charged
particle will penetrate in the course of slowing down to rest. This depth is
measured along the initial direction of the particle.

**Detour factor**: ratio of the projected range to the CSDA range.
As the result of multiple scattering, the trajectory of the particle is wiggly
rather than straight, and the detour factor is always smaller than unity.

**Radiation yield**: average fraction of the initial kinetic energy
of an electron that is converted to bremsstrahlung energy as a particle slows
down to rest, calculated in the continuous-slowing-down approximation.
Important only for electrons.

**
Introduction |
ESTAR |
PSTAR and ASTAR |
References |
Appendix**