Radiation source
OwnerDavid B. Chang, James C. McDaniel +3inventors
InventorsDavid B. Chang, James C. McDaniel, Norton L. Moise, Winfield W. Salisbury, I-Fu Shih
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Abstract
An improved radiation source is disclosed, exploiting the spontaneous radiation generated from the interaction of an electron beam and a conductive grating. Conditions are defined for generating coherent or noncoherent radiation, and for extending the tunability of the radiation source from millimeter, IR, visible and UV wavelengths to x-ray wavelengths, and for generating multiple wavelengths simultaneously. Conditions are disclosed for enhancing the intensity of the spontaneous radiation, anf for modulating the radiation.
Claims37
A radiation source for generating coherent radiation, comprising:
- an electrically conductive grating;
- an electron beam means for directing a beam of electrons above the grating so as to generate spontaneous radiaton from the interaction of the electron beam and the conductive grating;
- means for providing a periodic space-charge structure of electrons above said grating such that the spontaneous radiation passes through said space-charge structure;
- and
- wherein said space-charge structure further comprises means for amplifying said spontaneous radiation on passing through said space-charge structure by a factor greater than unity.
A source of coherent radiation, comprising:
- an electrically conductive grating having a grating spacing a;
- means for providing a periodic space charge structure of electrons above said grating;
- electron beam means for directing a beam of electrons through said periodic space charge structure, said electron beam having a natural plasma frequency comparable to the radiation frequency.
A radiation source, comprising:
- an electrically conductive cavity;
- an electrically conductive grating means disposed within the cavity;
- means for providing a periodic space charge structure of electrons above the grating;
- and
- electron beam means for directing a beam of electrons through said periodic space charge structure.
In a radiation source employing an electrically conductive grating and electron beam means for directing a beam of electrons above the grating so as to generate spontaneous radiation from the interaction of the electron beam and the conductive grating, the improvement wherein:
- the electrically conductive grating comprises a crystal having a reflective surface, wherein the spatial spacing of the grating is on the order of Angstroms, and the spontaneous radiation comprises x-ray wavelength radiation.
In a radiation source employing an electrically conductive grating and electron beam means for directing a beam of electrons above the grating so as to generate spontaneous radiation from the interaction of the electron beam and the conductive grating, the improvement wherein:
- the conductive grating comprises a superlattice structure comprising a reflective surface, wherein the spatial spacing of the grating is on the order of ten to one hundred Angstroms, and the spontaneous radiation comprises x-ray wavelength radiation.
A radiation source, comprising:
- electrically conductive grating whose elements are characterized by a predetermined blaze angle and a grating space a;
- electron beam means for directing a beam of electrons above said grating so that said electron beam collides with said grating at a grazing angle, whereby electrons reflected from the grating comprise a periodic space charge structure of aligned sheets of electrons above the grating;
- and
- wherein the grating blaze angle is selected to orient said sheets in a predetermined direction for which the maximum intensity of radiation is obtained.
A tunable radiation source adapted to selectively generate broadband incoherent radiation and coherent radiation over a broad frequency range, comprising:
- an electrically conductive grating;
- an electron beam generator for generating a high energy electron beam;
- means for directing the electron beam over said grating so as to collide with said grating, said means comprising selection means for selectively determining the angle at which said electron beam collides with said grating;
- means for selectively providing a well-defined space charge structure of electrons above said grating when said directing means causes the electron beam to collide with the grating at a grazing angle;
- whereby coherent spontaneous radiation is generated when the beam collides with the grating at a grazing angle, and Bremsstrahling radiation is generated when the collision angle is direct enough that a substantial number of the electrons are absorbed into the grating.
A radiation source, comprising:
- an electrically conductive grating having a grating element spacing;
- means for providing a periodic space charge structure of electrons above said grating;
- electron beam means for directing a plurality of beams of electrons of different electron energies through said periodic space charge structure, whereby spontaneous radiation of different wavelengths is generated from the interaction of the electron beams and the grating means, and whereby the wavelengths of the radiation are dependent on the electron energies and the grating spacing.
A radiation source, comprising:
- an electrically conductive grating comprising a plurality of grating elements having a first effective grating spacing in a first region and a second effective grating element spacing in a second region;
- means for providing a periodic space charge structure of electrons above said grating means;
- electron beam means for directing a beam of electrons through said periodic space charge structure,
- whereby spontaneous radiation of two different wavelengths is generated from the interaction of the electron beam and the two regions of the grating means, and whereby the radiation wavelengths are dependent on the electron energy and the grating element spacings.
Dependencies are inferred from the claim text.