High Efficiency Compact High Voltage Vector Inversion Generators
Vector Inversion Generators, VIG, were invented by Fitch and Howell1. The spiral-line VIG takes electrostatically stored energy and converts it into a fast rising high voltage pulse in a dynamic two component, one-step process. We present the results for a variety of units operating over a wide range of parameters. The highest voltage achieved in a single ultra-compact unit has been 500 kV in a device that is 8 inches long and 5 inches in diameter. Two of these units have been operated in tandem to produce a 1 MV pulse generator that failed after about 10 cycles. Finally, we discuss the range of loads that can be driven by this dynamic device in terms of the VIG dynamics and the RC time constant for the load.
High Pressure sealed hydrogen spark switches
High Pressure hydrogen spark switches offer excellent high voltage capabilities at high repetition rates. To date their availability has been limited due to the problems of hydrogen diffusion or leakage through the switch structure. In our laboratory, we are researching a series of miniature sealed hydrogen switches for a variety of applications. In this work, we will present data for prototype switches in terms of DC hold-off voltage, hold off voltage as a function of dV/dt, and consistency of these data as a function of life of the switch. To date, prototype switches in the range of 20–30 kV DC are functioning perfectly one year after fabrication. Limited data will also be presented on repetition rate in burst mode operation. Materials selection parameters will be discussed in terms of compatibility and ease of manufacture.
A technique for large-field, superficial electron therapy.
The application of electron beams to radiation therapy has received increased attention in recent years. This interest stems largely from the special characteristics of the electron depth-dose distribution; the fall-off in depth dose near the end of the range of the electrons is particularly rapid for electron beams having energies less than about 10 Mev. Such an electron beam is suitable for the treatment of widespread, superficial lesions, where it is desirable to minimize the dose to deep tissues. All the common sources of super-voltage x-rays, apart from radioactive substances, are inherently capable of producing an external beam of electrons, though with varying degrees of complexity. Electrons of about the energy suitable for superficial therapy (several Mev) may be used to produce an x-ray beam which is sufficiently penetrating for the treatment of even the deepest lesions. The Stanford medical linear accelerator was designed to provide both x-rays and electron beams. The accelerator and its applic...