Microwave Gas Discharge Research Articles

High Power, Magnetic Field Controlled Microwave Gas Discharge Switches

A new type of gas discharge switch is described, It is electronically controllable, broadband, and capable of rapidly switching high power pulsed microwaves from either of two waveguide input ports to a single waveguide output port, or from one waveguide input port to either of two waveguide output ports. The electronic control is achieved by turning on or off a magnetic field set for cyclotron resonance. An approximate analysis is given of the operation of the active element of the switch and the results are compared with experiment. An analysis of the effects of frequency scaling indicates that, with the exception of the magnetic flux density which increases with increasing frequency, the switch parameters either improve or remain unchanged in going to higher frequencies. Two different switch configurations are investigated, one a Y-junction switch for operation at S band and the other a balanced top-wall hybrid coupler switch for operation at K/sub u/ band. Their electrical characteristics are described.

Microwave gas discharge breakdown

A brief survey of microwave gas discharge breakdown is given. The conditions for breakdown in electron attaching and non-attaching gases is discussed. Results for air show both electron attachment and diffusion are operating. Hydrogen is taken as an example of a gas in which electron attachment is absent. For this case, data in the low pressure region, in the diffusion controlled region, and in the mobility controlled region are discussed and the results of the many studies in these regions are shown to be consistent with each other.

The spike in the transmit-receiver (TR) tubes

The spike leakage signal from high-Q and band-pass tr tubes was recorded as a function of time by using high-speed oscillographic techniques. Transients as short as 0.5 millimicro-seconds (0.5 × 10-9seconds) were resolved. The variation of the 1B24 high-Q tr spike was determined as a function of time for several experimental parameters including the gas type and pressure, initial number of electrons in the tr gap, and peak incident power supplied by the transmitter. Oscillographic recordings show the tr spike leakage power from a commercial gas-filled 1B24 tr tube rises to a peak of 0.3w in a time interval of 6 mµsec. The spike leakage power from a 5863 three-gap band-pass tr tube rises to a peak of 3.6w in 7.5 mµsec. Threshold of microwave gas discharge breakdown measurements in helium gas are used to determine the electric field intensity in the 1B24 tr gap as a function of the waveguide power. From this, the electron motion during the spike interval is calculated. The results indicate that production of electrons in the gap can occur through ionization of the gas by the electrons' radio frequency energies, and by secondary emission at the gap surfaces, as well as through ionization of the gas by the electrons' energies of random motion.

XLVIII. The Electron Affinity of Hydrogen in a Microwave Gas Discharge

ABSTRACT The electron captor gas most often used in microwave gas discharge devices such as transmit-receive switches is water vapour. It has been found that comparably short recovery (de-ionization) times are obtainable with hydrogen. This result is surprising in view of usually accepted values of the electron affinity of this gas.

The Direct Current associated with Microwave Gas Discharge between Coaxial Cylinders, IV

If the microwave gas breakdown once occurs, the microwave gas discharge continues even at the lower power and at the same time the direct current continues to flow, without application of any direct voltage, in the external circuit. From the observation of the length of the mierowave glow appearing along the axis of cylindrical cavity, the direct current J has been shown to be proportional to E and nearly inversely proportional to P , where E in the maximum value of the microwave electric field intensity and P the gas pressure.

On the Radial Extent of Glow in Microwave Gas Discharge between Coaxial Cylinders

On the Radial Extent of Glow in Microwave Gas Discharge between Coaxial Cylinders

The Direct Current associated with Microwave Gas Discharge between Coaxial Cylinders, III

The Direct Current associated with Microwave Gas Discharge between Coaxial Cylinders, III

The Direct Current associated with Microwave Gas Discharge between Coaxial Cylinders, II

If the microwave gas breakdown once occurs, the microwave gas discharge continues even at the lower power and at the same time the direct current continues to flow, without application of any direct voltage, in the external circuit. From the observation of the length of the mierowave glow appearing along the axis of cylindrical cavity, the direct current J has been shown to be proportional to E and nearly inversely proportional to P , where E in the maximum value of the microwave electric field intensity and P the gas pressure.

The Direct Current associated with Microwave Gas Discharge between Coaxial Cylinders, I

The Direct Current associated with Microwave Gas Discharge between Coaxial Cylinders, I

Microwave gas discharges

The microwave gas discharge has presented a new field for physical exploration. The r e sults of some of these experiments are given here; processes active in a microwave gas discharge are discussed, and a formula is developed for the complex conductivity of the discharge from the known properties of electrons and ions.

A Microwave Gas Discharge Counter for the Detection of Ionizing Radiation

Characteristics of a gamma-ray counter making use of a 3000-megacycle gas discharge in a coaxial mode cavity resonator are described. The breakdown of a discharge in gases at these frequencies does not depend upon secondary effects. Since the breakdown is not controlled by positive ions, shorter breakdown and resolving times than those of a Geiger-Müller counter are realized. In the high frequency discharge, ambipolar diffusion is the controlling factor in loss of electrons. A d.c. clearing field is superimposed on the a.c. field to eliminate electrons rapidly. A quenching agent is present to suppress electron emission from positive ion bombardment of the walls. The discharge is extinguished by reducing the magnetron power electronically. The plateau and sensitivity characteristics are similar to those of a Geiger-Müller counter.