Dear all, I am reading the "Techniques for Nuclear and Particle Physics Experiments" of W.R.Leo. I am confused when reading the section 2.2. Energy Loss of Heavy Charged Particles in Atomic Collisions (page 21). At the beginning of the second paragraph (from the bottom up), it is written that "Of the two electromagnetic processes" ? Why is it written like this? I think electromagnetic processes are X-rays, gamma-rays, etc., but not charged particles ! Please give me some explanations or advises if you have. Thanks in advance !