Abstract: A laser comprising an RF matching unit having an RF power input and an RF power output, an optical cavity including electrode apparatus extending along the optical cavity, receiving the RF power output and defining a discharge gap having a gaseous lasing medium disposed therein, the RF power output being operative to produce a population inversion in the gaseous lasing medium, and an arrangement for providing direct fluid cooling contact with the electrode apparatus generally along its entire extent.

Abstract: A radio frequency surface probe for data acquisition in magnetic resonance systems. The probe is comprised of a plurality of inductors connected together with tuning capacitors in a balanced configuration. The configuration enables the probe to be impedance matched and to resonate at two separate frequencies without having to be tuned between frequency settings and without being effected by the impedance variations that are caused by the different samples or patients.

Abstract: An Rf coil arrangement for MRI systems wherein the electrical length is reduced to improve the S/N ratio and the Rf power efficiency.

Abstract: The feed point of a whip antenna having a length less than one quarter-wavelength at the lowest frequency of operation is raised above a counterpoise ground plane by a short base sleeve. Gain over a 2.5:1 bandwidth of radio frequencies closely approaches the gain of a standard quarter-wavelength antenna without requiring use of power-dissipating resistance loading. A ferrite transformer at the whip antenna feedpoint is utilized to reduce the high anti-resonance impedance of the broadband whip antenna to the characteristic impedance of a coaxial cable transmission system and to minimize the VSWR thereof. The base sleeve raises the antenna resistance at the resonant frequency near the lower end of the bandwidth to make the transformer effective as an impedance matching element over the entire radio frequency band.A pair of the whip antennas are axially aligned and electrically coupled in series to realize a broadband dipole having increased gain.

Abstract: A whip antenna with a substantially constant impedance over a broad band of radio frequencies includes a mounting section, a high-power-dissipation low-resistance assembly, a first whip section, a second whip section, and a high-impedance quarter-wavelength transformer section concentrically formed around the first whip section and extending from the resistance assembly to the junction of the first and second whip sections. The low-resistance termination is attached close to the base of the antenna and is transformed to a high resistance at the junction of the first and second whip sections at the frequency where the matching section length equals one quarter-wavelength. The resistive power loss only occurs over a limited band centered at the design frequency of the matching section. Instability caused by emplacement of a high-mass resistive termination towards the top of the complete antenna is thus avoided.