Electron orbit control in a betatron
AssigneeSchlumberger Technology Corporation
InventorFelix K. Chen
Life of this patent
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Abstract
A betatron, adapted, e.g., for use as a high-energy electromagnetic radiation source in a borehole well logging tool, includes modulator circuitry for actively controlling the electron beam radius during acceleration and for extracting the electron beam at or near maximum magnetic field strength. Such control may be effected by suitable separate pulsing of field-coil and core-coil magnets, and results in enhanced efficiency of betatron magnet-excitation power conversion and beam end-point energy stability and intensity over a range of operating temperatures.
Claims11
A modulator circuit for a betatron having at least one magnetizing winding, comprising:
- a low-voltage d.c. power supply;
- means defining a low-voltage capacitive circuit coupled between one pole of said power supply and one side of said magnetizing winding;
- means defining a high-voltage capacitive circuit coupled between the other side of said magnetizing winding and the other pole of said power supply;
- switching means for repetitively permitting electrical current flow from said power supply through said low-voltage capacitive circuit and said magnetizing winding to charge said high-voltage capacitive circuit and for reversing electrical current flow between said high-voltage capacitive circuit and said low-voltage capacitive circuits to discharge the electrical energy stored in said high-voltage circuit and low-voltage capacitive circuits through said magnetizing winding, whereby an electron beam captured in the magnetic field generated by said magnetizing winding is accelerated;
- and
- means for extracting the electron beam when the magnetic field generated by the magnetizing winding is substantially at peak value.
A modulator circuit for a betatron having a field-coil winding and a core-coil winding, comprising:
- a low-voltage d.c. power supply;
- low-voltage capacitive means and high-voltage capacitive means coupled across the power supply;
- the field-coil and core-coil windings being coupled in inductive charging relationship between the low-voltage and high-voltage capacitive means;
- first unidirectional current means operatively coupled between the field-coil and core-coil windings and the second capacitive means for normally permitting current flow from the first capacitive means through the field-coil and core-coil windings to the second capacitive means but preventing reverse current flow;
- first switching means for selectively reversing the direction of current flow between the high-voltage capacitive means and the low-voltage capacitive means to discharge the energy stored in the low-voltage and high-voltage capacitive means into the field-coil and core-coil windings;
- third capacitive means coupled in parallel with the high-voltage capacitive means via second switching means and second unidirectional current means, said second unidirectional current means permitting charging of said third capacitive means concurrently with the charging of said high-voltage capacitive means but preventing reverse current flow;
- and
- control means for actuating the second switching means to discharge said third capacitive means into the core-coil winding to cause extraction of the electron beam.
Dependencies are inferred from the claim text.