| 摘要 |
A non-radioactive source for Atmospheric Pressure Ionization is described. The electron-beam sealed tube uses a pyroelectric crystal(s). One end of the crystal is grounded while the other end has a metallic cap with sharp feature to generate an electron beam of a given energy. The rate of heating and/or cooling of the crystal is used to control the current generated from a tube. A heating and/or cooling element such as a Peltier element is useful for controlling the rate of cooling of the crystal. A thin window that is transparent to electrons but impervious to gases is needed in order to prolong the life of the tube and allow the extraction of the electrons. If needed, multiple crystals with independent heaters can be used to provide continuous operation of the device. The energy of the electrons can be determined through the appropriate choice of the radius of curvature of the sharp feature and the gap between the sharp feature and the window, while the opposite side of the crystal is at low voltage. The size of the gap and the radius of curvature of the sharp feature are determined by the filling gas nature and pressure.
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