I'm wondering if there is an explanation for clean Bremsstrahlung emissions with out characteristic X-Rays apart from Axil's interesting explanation (which maybe the correct one) of broad spectrum emissions from SPP.
First some well known background about Bremsstrahlung that I'm sure you are all familiar with: If we do have Bremsstrahlung radiation due to high energy electrons this will radiate photons with a broad range of frequencies with a range starting and rising very quickly to a peak intensity at frequencies near the plasma frequency in the material then decreasing to zero intensity at frequencies corresponding to the energy of the kinetic energy Q value of the electrons. The plasma frequency in metals is typically in the UV region maybe 5 to 20 eV. The Q value depends on the energy of the source electrons or beta and can vary a lot in energy depending on the source energy they can be a 10s keV but can also be even be at very high energies corresponding to very hard X-rays at gamma frequencies say to 1.5 MeV or more for example, especially if due to a nuclear source such as beta decay. The highest emission intensity however will typically be between the plasma frequency and a few tens or hundreds keV. Thermal distribution and relativistic effects on the electron energies can also have a small effect on the on the photon emission profile. Normally interactions of Bremsstrahlung electrons with atoms can lead to characteristic X-Ray emission at a few 10s keV from excitation inner electron transitions in the atom after Auger electrons are released. These are usually visible as distinct peaks on top of the broad Bremsstrahlung emission spectrum. Given this background I have a few questions: The Fermi Energy in metals is also a few eV typically 2 to 10 eV. What would be the impact of the bremsstrahlung radiation photon emission at energies above the Fermi energy for the metals? Wouldn't these metals start to become ionised and the electrons start to move independently of the nuclei? (Perhaps this behaviour is what we expect tied to the plasma frequency and bulk or surface plasmons production). With such a broad range of frequencies in the Bremsstrahlung could the atoms become more heavily ionised? Increasing slightly the electron density and strength of interaction of fast electrons with the ions? Thereby enhancing the Bremsstrahlung. Would the high intensity but Low energy Bremsstrahlung photons (UV to low energy X- Ray) excite the high energy electron energy transitions in the nuclei? Or perhaps even knock out inner shell electrons. I think I read somewhere this has be observed astronomically. Could such excited atoms can achieve Rydberg state too? And ultimately for Rydberg matter? Once the metal atoms are excited into these high energy states, particularly if the inner electrons are removed from their inner orbitals I suppose further bremsstrahlung interactions of high energy electrons with those atoms would no longer produce characteristic X-Ray's? At least until the nuclei were no longer energised and able to de-excite back to their ground level i.e. during cool down? Sent from my iPad
