Abstract: The improved cathode sub-assembly includes a solid cylindrical cathode of tungsten, a cylindrical holder concentric to the cathode with an internal radially directed rib receiving one end of the cathode, and a cylindrical reflector threadably mounted within the holder in circumferentially spaced relation to the cathode. The holder is threadably mounted in a support plate to be able to be readily removed for servicing and/or replacement.

Abstract: The improved cathode sub-assembly includes a solid cylindrical cathode of tungsten, a cylindrical holder concentric to the cathode with an internal radially directed rib receiving one end of the cathode, and a cylindrical reflector threadably mounted within the holder in circumferentially spaced relation to the cathode. The holder is threadably mounted in a support plate to be able to be readily removed for servicing and/or replacement.

Abstract: A system including: a computer system configured to: access geographical information system (GIS) data, including land-parcel data representing land-parcel coordinates that define a plurality of land parcels, and publicly accessible destination data representing coordinates of publicly accessible destinations, and/or publicly accessible region data representing one or more regions with associated features, and process the GIS data to generate processed GIS data representing attributes of each land parcel associated with: distances between each land parcel and the publicly accessible destinations; and/or features of the regions that overlap with the land-parcel coordinates; and at least one server configured to: receive request data representing query criteria for selecting ones of the land parcels; filter the processed GIS data to select ones of the land parcels with distances and/or features matching the query criteria; and generate response data representing the selected ones of the land parcels.