Electron slowing down

An X-ray source consists of a target which is bombarded with high energy electrons. The emitted X-rays arise from two processes. Electrons slowed down by the target emit a continuous background spectrum of Bremsstrahlung. Superimposed on this are characteristic, narrow lines. The Cu Ka line, for example, arises because a primary electron creates a core hole in the K shell, which is filled by an electron from the L shell (K(3 the K-hole is filled from the M-shell, etc.) under emission of an X-ray quantum. The process is called X-ray fluorescence. It... 

For all detector types, the transfer of energy to the detector material as the photoelectrons and recoil electrons slow down occurs through excitation or ionization of electrons in neighboring atoms within the detector structure. What occurs next depends on the specific molecular structure of the detector. We can distinguish between structures such as noble gases, photoconductors, fluorescent phosphors, and photostimulable phosphors. 

Theoretical calculations have been made of the yields of ionization, singlet and triplet excitation for 100-keV electrons slowing down, using the so-called binary-encounter collision theory Yields for the various processes have been calculated for electrons originating from three orbitals (lt2> and la ) with ionization potentials 13.0eV, 23.1 eV and 290.7 eV, respectively. 

Shell electrons Slowing down Excitation, ionization, transition radiation Cherenkov radiation... 

As described previously, the fast electrons slow down gradually losing --10-40 eV energy in each interaction. As the kinetic energy of the incident particle drops below a certain value, 100 eV (Case c), there is no more possibility of a sudden energy transfer like with a last particle (Bednar 1983). Therefore, the optical approximation loses its validity, and optically not allowed transitions may also occur in the energy transfer process there is a direct possibility for excitation to triplet excited states. 

CF3H 0.27 Weakly electron-attaching some (CO, N2O) are effective in electron slowing-down... 

---