Abstract: The x-ray source of the present invention comprises a charged particle beam generator and a vacuum enclosure assembly. The charged particle beam generator includes only a single electrical connection for providing high voltage to the electron gun. The power for the active circuits in the high voltage terminal of the charged particle beam generator is provided by a unique isolation transformer that has minimal losses and generates controlled magnetic flux. The generated charged particle beam is controlled through a series of dynamic and static focus coils and moved across the inner face of the target by a stepping coil assembly comprising x and y deflection coils as well as an x step and preferably a y step coil. Further, to minimize power usage, a control grid pinches off the charged particle beam during the stepping of the beam.

Abstract: An ultrasonic detector for detecting air in a fluid passage is disclosed. The detector comprises a transmitting crystal and complementary receiving crystal disposed around the fluid passage. A sweep oscillator is used to apply a variable-frequency signal to drive the transmitting crystal into resonance so that a burst of ultrasonic energy is released therefrom. The swept frequency range encompasses the resonant frequency of the transmitting crystal, ensuring that it resonates. If there is fluid in the passage, the ultrasonic energy causes a relatively high voltage to develop across the receiving crystal. Air in the passage attenuates transmission of the ultrasonic energy so that a low voltage signal is developed across the receiving crystal. A sensor circuit connected to the receiving crystal monitors the signal developed thereacross and in response to the magnitude of the signal, asserts a signal that indicates whether there is air or fluid in the passage.

Abstract: An improved electrographic writing head employs interleaved arrays of writing nibs and small geometry, high impedance, thick film resistors and semiconductor driver circuits fabricated on a glass epoxy substrate. The writing head achieves significant savings in manufacturing costs by using low cost printed circuit and thick film technology. Power consumption may be reduced by more than half over prior art devices due to the high impedance of each thick film pull up resistor coupled with a associated writing neb. A ground plane is disposed internally of the substrate and between adjacent arrays of writing nibs. The ground plane prevents electrical interaction between the substrates and prevents the formation of parasitic nib-to-nib capacitance by shunting parasitic capacitance currents to ground. The ground plane thus reduces the possibility of flaring and substantially eliminates inadvertent writing by adjacent nibs.

Abstract: An improved electrographic writing head employs interleaved arrays of writing nibs and small geometry, high impedance, thick film resistors and semiconductor driver circuits fabricated on a glass epoxy substrate. The writing head achieves significant savings in manufacturing costs by using low cost printed circuit and thick film technology. Power consumption may be reduced by more than half over prior art devices due to the high impedance of each thick film pull up resistor coupled with a associated writing nib. A ground plane is disposed internally of the substrate and between adjacent arrays of writing nibs. The ground plane prevents electrical interaction between the substrates and prevents the formation of parasitic nib-to-nib capacitance by shunting parasitic capacitance currents to ground. The ground plane thus reduces the possibility of flaring and substantially eliminates inadvertent writing by adjacent nibs.

Abstract: A pressure sensor assembly includes two spacedly positioned flexible supports which support an elongated rod, with one end of the elongated rod contacting a pressure detector section on a disposable pumping cassette; the pressure sensor assembly can detect pressures in the cassette both above and below atmospheric (i.e., zero psig); when pressure changes in the cassette, the pressure detection section causes axial movement of the rod and the rod, in turn, flexes the two flexible supports. Position detection means associated with one of the two supports monitors the flexural movement of the one support, providing an indication of the pressure within the cassette.

Abstract: An ultrasonic sound generator and receiver are spaced apart from each other so as to receive a projecting portion of a cassette in which a liquid carrying passage is defined by a flexible membrane. The liquid carrying passage in the projecting portion fits between the ultrasonic sound generator and receiver, with opposite sides of the flexible membrane in contact with the sound generator and sound receiver. The sound generator and sound receiver each comprise a substrate having a layer of conducting material. Two electrically isolated regions are defined on the conductive layer, and a piezoelectric chip is electrically connected between the two regions. An electrical signal applied between the first and second regions excites the piezoelectric chip on the sound generator, causing it to generate an ultrasonic signal, which is transmitted through the liquid carrying passage.

Abstract: An ultrasonic detector for detecting air in a fluid. A fluid pumping cassette includes an elastomeric member that defines three sides of a fluid passageway, a base of the cassette defining the other side. Resilient lobes on the elastomeric member extend outwardly in opposite directions on each side of the passageway, directly contacting an ultrasonic sound generator on one side and a piezoelectric sound receiver on the opposite side, the direct contact enhancing transmission of an ultrasound signal through the elastomeric member to facilitate detection of an air bubble in the fluid passage.

Abstract: A driver for use in an infusion pumping cassette having an elongated valve actuator which operates a valve controlling the flow of fluid through the cassette, a bracket having a first arm pivotally secured to one end of the valve actuator and a second arm, a cam driveably engaging the second arm, a motor which drives the cam and a positioner which monitors the rotational position of the cam.