Abstract:
An optical detector in a high voltage system senses the blue glow discharge characteristic of insipient failure in rectifier tubes and removes system power. In a preferred embodiment the rectifier tubes are part of a voltage multiplier in a charged particle accelerator and an RF transformer is part of the high voltage supply. Another optical detector is employed to remove power from the accelerator upon sensing blue light in an arc discharge at the RF transformer coil.
Abstract:
A high voltage solid-state rectifier includes multiple series connected ac-compensated diodes and series buffer resistors in a stepped spiral stack. The stack is encased in a sectionalized faraday shield which provides 360* isolation from external rf electrostatic fields and provides external capacitance grading along the stack. Spark gaps between shield sections prevent excessive voltage build-up due to electrical discharges and are arranged in line of sight of each other to permit the ultraviolet light produced from one spark gap firing to stimulate the firing of the other spark gaps. A trigger spark-gap derives its voltage from an inductance in series with the solid-state rectifier. Any electrical discharges which result in an excessive voltage appear initially across the inductance, firing the trigger spark gap which in turn initiates the other spark gaps to fire by ultra-violet stimulation.
Abstract:
Improved focusing of a beam of charged particles is achieved in an acceleration tube comprising alternate insulating rings and apertured electrodes to which progressively increasing electric potentials are applied to create an electric field for accelerating the charged particles along the length of the tube. In order to achieve precise beam focusing for different electric field strengths the aperture of the grounded electrode at the tube entrance is covered with a grid-like structure and a variable control voltage is applied to a downstream control electrode. For different field strengths the control voltage is adjusted to modify the field between the grounded and control electrodes to provide a variable lens effect. A preferred embodiment employs a variable resistor connected between the grounded and control electrodes to provide the variable control voltage.
Abstract:
A power supply for high voltage accelerators employs a plurality of elongated cylindrical capacitors, disposed circumferentially about a plurality of centrally located solid state rectifiers. The plates of each capacitor comprise inner and outer coaxial sleeves located in a gaseous atmosphere with A.C. applied to the inner sleeves to provide large effective spacing between the A.C. driven sleeves of the capacitors, the inner sleeves being shielded from one another by the outer sleeves. Solid state rectifiers require lower driving frequencies than are normal in such supplies. Output voltage loss resulting from use of lower frequencies is compensated by the large capacitance achieved and the use of a lesser number of rectifier stages. Peak inverse voltage limitations of the rectifiers are met by cascading rectifiers per stage, the large central space provided by the capacitor structure providing the space necessary for cascading.
Abstract:
In a particle accelerator of the type employing AC primary power and a voltage multiplication apparatus to achieve the required high DC accelerating voltage, a filament supply circuit is powered by a portion of the AC primary power appearing at the last stage of the voltage multiplier. This AC power is applied across a voltage regulator circuit in the form of two zener diodes connected back to back. The threshold of the zeners is below the lowest peak-to-peak voltage of the AC voltage so that the regulated voltage remains constant for all settings of the adjustable acceleration voltage. The regulated voltage is coupled through an adjustable resistor and an impedance-matching transformer to the accelerator filament.