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    EMISSION CURRENT CONTROL SYSTEM FOR MULTIPLE HOLLOW CATHODE DEVICES
    61.
    发明专利
    EMISSION CURRENT CONTROL SYSTEM FOR MULTIPLE HOLLOW CATHODE DEVICES 未知

    公开(公告)号：CA1273497A

    公开(公告)日：1990-09-04

    申请号：CA542033

    申请日：1987-07-14

    Applicant: HUGHES AIRCRAFT CO

    Inventor： BEATTIE JOHN R ,  HANCOCK DONALD J

    IPC: F01K21/04 ,  F02C3/30 ,  F02C6/18 ,  F03H1/00 ,  H01J3/08 ,  H01J27/02 ,  H05H1/00

    Abstract: An emission current control system for balancing the individual emission currents from an array of hollow cathodes has current sensors for determining the current drawn by each cathode from a power supply. Each current sensor has an output signal which has a magnitude proportional to the current. The current sensor output signals are averaged, the average value so obtained being applied to a respective controller for controlling the flow of an ion source material through each cathode. Also applied to each controller are the respective sensor output signals for each cathode and a common reference signal. The flow of source material through each hollow cathode is thereby made proportional to the current drawn by that cathode, the average current drawn by all of the cathodes, and the reference signal. Thus, the emission current of each cathode is controlled such that each is made substantially equal to the emission current of each of the other cathodes. When utilized as a component of a multiple hollow cathode ion propulsion motor, the emission current control system of the invention provides for balancing the thrust of the motor about the thrust axis and also for preventing premature failure of a hollow cathode source due to operation above a maximum rated emission current.

    WIRE ION PLASMA ELECTRON GUN
    62.
    发明专利
    WIRE ION PLASMA ELECTRON GUN 未知

    公开(公告)号：GB2203889A

    公开(公告)日：1988-10-26

    申请号：GB8806912

    申请日：1988-03-23

    Applicant: RPC IND

    Inventor： FARRELL SHERMAN R ,  SMITH RICHARD R

    IPC: H01J27/08 ,  H01J3/02 ,  H01J27/20 ,  H01J33/00 ,  H01J37/06 ,  H01J37/08 ,  H01J3/08

    Abstract: An ion plasma electron gun for the generation of electron beams which exhibits electron beam dose uniformity and which is capable of varying the dose received by a material to be irradiated. Positive ions generated by a wire in a plasma discharge chamber are accelerated through an extraction grid onto a second chamber containing a high voltage cold cathode. These positive ions bombard a surface of the cathode, causing the cathode to emit secondary electrons which form an electron beam. After passing through the extraction grid in the plasma discharge chamber, the electron beam exits from the gun by way of a second grid and a foil window supported on the second grid. The gun is constructed so that the electron beam passing through the foil window has a relatively large area and uniform electron distribution which is subsantially the same as the ion distribution of the ion beam impinging upon the cathode. Means are provided for creating a pulse of secondary electrons by varying the period of time in which the secondary electrons are transmitted through the foil.

    LASER SYSTEM WITH INTERCHANGEABLE MODULES AND METHOD FOR INTERCHANGING SUCH MODULES
    63.
    发明专利
    LASER SYSTEM WITH INTERCHANGEABLE MODULES AND METHOD FOR INTERCHANGING SUCH MODULES 未知

    公开(公告)号：CA1224557A

    公开(公告)日：1987-07-21

    申请号：CA451252

    申请日：1984-04-04

    Applicant: JAVAN ALI

    Inventor： JAVAN ALI

    IPC: H01J3/02 ,  H01S3/03 ,  H01S3/05 ,  H01S3/08 ,  H01J3/08

    Abstract: A gas laser is provided in which either or both of two "plug-in" modules, one of which comprises the plasma chamber and the other of which comprises the associated high voltage components and circuitry, can be quickly and easily replaced by relatively unskilled personnel without any need for optical realignment. This feature makes it possible to use sealed plasma chambers even in applycations where lasers are operated only intermittently and the sealed plasma chambers have limited operating life. With the elimination of the gas handling system, it becomes possible to manufacture compact, and in some important cases, portable and light weight lasers with replaceable plasma chambers and high voltage circuits. The invention is addressed to lasers operating at low to medium power output. In a preferred embodiment, each high voltage electrode of the plasma chamber includes a connector plate that extends through the envelope and removably engages a support plate of the module containing the high voltage pulse circuitry. These support plates are precisely positioned with respect to two resonator mirrors mounted permanently on a base structure, while the connector plates are precisely positioned with respect to the electrodes and windows of the plasma chamber. The positioning of the connector plates with respect to the electrodes, the windows and the optical axis is identical for each of the interchangeable plasma chambers. The module containing cont... the high voltage circuitry is releasable positioned on the base by two or more locator pins that retain it in a precise predetermined spatial and angular position with respect to the two mirrors. The position of this module with respect to the mirrors is identical for each of the interchangeable modules. The plasma chamber module thus "plugs in" to the high voltage module which in turn "plugs in" to the base structure. Either or both of the modules are readily exchanged with any other similar modules without optical realignment.

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