Chapter 2: Interactions of Heavy Particles with Matter

18 flashcards · Biology · by Kristóf Nagy

1. Stopping power (S)

   The kinetic energy loss of an ion per unit distance travelled through a material.15

2. Maximum energy transfer (Q_max)

   The maximum amount of kinetic energy that can be transferred from a heavy particle to an electron in a single collision.14

3. Lorentz factor (γ)

   A factor that accounts for the relativistic effects of velocity on mass and energy.14

4. Range straggling

   The statistical variation in the range of particles in a material.24

5. Relativistic velocity

   A velocity that is a significant fraction of the speed of light, requiring relativistic calculations.1314

6. Energy straggling

   The statistical variation in the energy lost by particles as they travel through a material.24

7. Inelastic collision

   A collision where kinetic energy is not conserved.13

8. Elastic collision

   A collision where both momentum and kinetic energy are conserved.13

9. Heavy particle

   A charged particle heavier than an electron/positron, with high energy (ionizing radiation) in the MeV range. Includes protons, alpha particles, and heavier ions.12

10. Term

    Definition

11. Bragg peak

    A sharp peak in the energy deposition profile of heavy charged particles near the end of their range.24

12. Bragg's rule

    A rule used to calculate the stopping power of a compound material by considering the weighted average of the stopping powers of its individual elements.23

13. Mean excitation energy (I)

    The average energy required to excite an electron in a material.202122

14. Bethe-Bloch formula

    A quantum mechanical formula that describes the stopping power of a material for charged particles.1819

15. Impact parameter (b)

    The perpendicular distance between the path of a projectile and the centre of the target.17

16. Mean free path

    The average distance a particle travels between collisions.16

17. Macroscopic cross section (μ)

    The probability of a collision per unit length. Related to the mean free path.16

18. Linear Energy Transfer (LET)

    The amount of energy deposited by ionizing radiation per unit distance travelled in a material. Similar to stopping power but only includes energy deposited locally near the track.15