Sorry a couple of time I said nuclei but I meant atoms. This is about electron atom interactions not nucleus excitations.
Sent from my iPad > On 11 mrt. 2016, at 23:33, Stephen Cooke <[email protected]> wrote: > > 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
