Thermo Scientific Portable Analytical Instruments Inc.

Moxtek, Inc.

Twx, LLC

David J Caruso

Mark T Dinsmore

An x-ray beam control system includes a feedback control loop circuit having a modulation circuit. The feedback control loop circuit generates a control signal. A x-ray tube, has a filament response profile of tube current versus filament temperature that is non-linear. A compensation circuit receives the control signal and modifies the control signal according to a compensating function that is matched to the filament response profile. The modulation circuit receives the modified control signal and generates a drive signal. The x-ray tube receives the drive signal at a filament thereof, and outputs a tube current signal having a linear response to the control signal. The feedback control loop circuit receives the tube current signal.

Dynamically adjustable filament control through firmware for miniature x-ray source

An electrically heated planar cathode for use in miniature x-ray tubes may be spiral design laser cut from a thin tantalum alloy ribbon foil (with grain stabilizing features). Bare ribbon is mounted to an aluminum nitride substrate in a manner that is puts the ribbon in minimal tension before it is machined into the spiral pattern. The spiral pattern can be optimized for electrical, thermal, and emission characteristics.

Electrically heated planar cathode

A high-voltage isolation transformer utilizing balun cores for transferring an alternating current signal from a first circuit to an output circuit, and a high voltage generator, such as a Cockcroft-Walton multiplier to apply a high direct current voltage bias with a high degree of voltage isolation between the first circuit and the output circuit. Multiple balun core transformers can be used in order to reduce the voltage rise between each individual transformer.

Transformer with high voltage isolation

An x-ray source includes an insulating tube having a cylindrical inside surface defining a cylindrical vacuum cavity, a cathode located near a first end of the insulating tube and adapted to be optically heated for emitting electrons, an anode adapted for a voltage bias with respect to the cathode for accelerating electrons emitted from the cathode, an x-ray emitter target located near a second end of the insulating tube for impact by accelerated electrons, and a secondary emission reduction layer covering at least a portion of the inside surface and adapted to minimize charge build-up on the inside surface, wherein the insulating tube is adapted to be weakly conductive to support a uniform voltage gradient along the insulating tube and across the voltage bias between the cathode and the anode.

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Groton, MA, United States of America

David J Caruso