Abstract: An ultrasonic transducer employed for both transmitting ultrasonic acoustic energy into an immersion medium and for detecting acoustic energy reflected from an object under examination is provided, the transducer having a hybrid transmitter and receiver in which a ceramic piezoelectric material is used to construct a first piezoelectric element for transmitting the acoustic energy, and a polymer piezoelectric material is used to fabricate a second piezoelectric element for receiving the reflected acoustic energy. The hybrid ultrasonic transducer provides improved performance over prior transducers using only a single ceramic piezoelectric element, in that the good transmitting properties of the ceramic are preserved, while the better receiving properties of the polymer piezoelectric are used to improve the sensitivity of the transducer. The polymer piezoelectric has the further advantage of providing a closer match of acoustic impedance to the immersion fluid used in the evaluation of objects.

Abstract: A microfocus X-ray tube has an anode that emits X-rays and, a biproduct of its waste heat, visible and near infrared light. This invention uses the biproduct light to adjust and maintain the focus of the electron beam and enhance the performance of the X-ray tube as a point source of X-rays. Only the light is reflected by a mirror along a path in which a viewport is placed in the tube envelope. An sensor, e.g., a photodiode, or television camera, is placed in the path. A display means, e.g., a television display, meter, etc., can be connected to the sensing means to display the emitting spot of the anode or the amplitude of the emission. The focus of the X-ray tube is assured by observing the biproduct light and adjusting the electron beam to either minimize the size of the glowing spot or maximizing its apparent brightness. A method for use with an emitter of first and second types of radiation comprises reflecting only the second type of radiation, and sensing the reflected radiation.

Abstract: A broadband 25 to 50 MHz spherically focused ultrasonic transducer is placed on the tip of a catheter such that ultrasonic images of arteries and plaque are produced by introducing the catheter into arteries of patients. The high frequency transducer has thin piezoelectric polymer film as the transducing element and is adhered to a depression in the reduced cross section catheter tip. A coaxial cable in the catheter connects the transducer to an external signal source and a display for the received signals. The diagnosis and characterization of arterial disease is most often coupled with a therapeutic technique such as balloon angioplasty.

Abstract: An imaging X-ray sensor is composed of a linear array of microscopically small bars of polycrystalline ceramic scintillator material bonded at the bar ends to an integrated circuit photodetector array. The scintillator bars are the basic resolution elements of the detector and are less than 50 microns in width. Each bar produces a flash of light with intensity related to the X-ray flux penetrating the bar. A reflective coating covering five surfaces of the bars isolates each detector element and channels the light into the photodetector bonded to one end of the bar. A method of fabricating the detector array utilizes the machineability and good mechanical strength of scintillators such as rare earth oxides doped with rare earth activators.

Abstract: A method for aligning a X-ray beam collimator to a linear array X-ray detector. The method computes a horizontal centerline on the detector and a horizontal centerline the collimator. The horizontal centerlines are then aligned. Vertical centerlines are computed for the detector and collimator. A thickness for a shim is computed from the difference in the vertical centerlines. The collimator is installed on vertical standoffs with the shims inserted between the collimator and standoffs. The shims align the collimator and detector in the vertical direction.

Abstract: Improved focussing and increased bandwidth is obtained in a single-element ultrasonic transducer for non-destructive evaluation and material characterization applications. The piezoelectric ceramic element has a radius of curvature R.sub.1, and a combination lens and cover layer on its front surface has a radius of curvature R.sub.2 which is less than R.sub.1. The depth of field of the transducer is increased and the bandwidth improved; the total thickness of the lens may be selected to control bandwidth.

Abstract: A high frequency ultrasonic transducer is improved by fabricating the tungsten-polyvinyl chloride composite, which backs the elements, in a specific manner. Small particle size tungsten powder and PVC powder are placed into a high pressure die. Standard processing of the powder mixture includes degasing followed by heating and compressing. To maximize the acoustic attenuation, the pressure applied to the mixture is maintained until it has cooled down. The composite is in a state of elastic compression and spontaneously expands when removed from the die, giving rise to the high levels of acoustic attenuation.

Abstract: The variety of technologies that have been applied in the development of a onded grid cathode are described. These include chemical vapor deposition of tungsten, molybdenum, iridium, BM, and Si.sub.3 N.sub.4 on both sides of a sintered tungsten cathode disk. Zirconium and titanium getters have been used to eliminate nitrogen evolution problems. Films of Si.sub.3 N.sub.4 have been added to the insulation to prevent calcium and barium diffusion into the layer and maintain adequate resistivity and breakdown strength. Plasma etching was introduced as a method of removing Si.sub.3 N.sub.4 from the cathode pores.