In some embodiments, a gas discharge tube (GDT) can include first and second electrodes each including an edge and an inward facing surface, such that the inward facing surfaces of the first and second electrodes face each other. The GDT can further include a sealing portion implemented to join and seal the edge portions of the inward facing surfaces of the first and second electrodes to define a sealed chamber between the inward facing surfaces of the first and second electrodes. The GDT can further include an electrically insulating portion implemented to provide a surface in the sealed chamber and to cover a portion of the inward facing surface of each of at least one of the first and second electrodes such that a leakage path within the sealed chamber includes the surface of the electrically insulating portion.

A gas discharge tube (GDT) can include first and second electrodes each including an edge and an inward facing surface, such that the inward facing surfaces face each other. The GDT can further include a sealing portion implemented to join the edge portions of the first and second electrodes to form a chamber between the inward facing surfaces of the first and second electrodes. The GDT can further include an electrically insulating portion implemented to provide a surface that covers a portion of the inward facing surface of each of at least one of the first and second electrodes such that a leakage path between the first and second electrodes includes a path on the surface of the electrically insulating portion.

Glass sealed gas discharge tubes. In some embodiments, a gas discharge tube (GDT) can include an insulator substrate having first and second sides and defining an opening. The GDT can further include a first electrode implemented to cover the opening on the first side of the insulator substrate, and a second electrode implemented to cover the opening on the second side of the insulator substrate. The GDT can further include a first glass seal implemented between the first electrode and the first side of the insulator substrate, and a second glass seal implemented between the second electrode and the second side of the insulator substrate, such that the first and second glass seals provide a hermetic seal for a chamber defined by the opening and the first and second electrodes.

An ion source has an arc chamber having an arc chamber body. An electrode extends into an interior region of the arc chamber body, and a cathode shield has a body that is cylindrical having an axial hole. The axial hole is configured to pass the electrode therethrough. First and second ends of the body have respective first and second gas conductance limiters. The first gas conductance limiter extends from an outer diameter of the body and has a U-shaped lip. The second gas conductance limiter has a recess for a seal to protect the seal from corrosive gases and maintain an integrity of the seal. A gas source introduces a gas to the arc chamber body. A liner has an opening configured to pass the cathode shield therethrough, where the liner has a recess. A gap is defined between the U-shaped lip and the liner, wherein the U-shaped lip reduces a conductance of gas into the gap and the recess further reduces conductance of gas into the region.

An ion source has an arc chamber having an arc chamber body. An electrode extends into an interior region of the arc chamber body, and a cathode shield has a body that is cylindrical having an axial hole. The axial hole is configured to pass the electrode therethrough. First and second ends of the body have respective first and second gas conductance limiters. The first gas conductance limiter extends from an outer diameter of the body and has a U-shaped lip. The second gas conductance limiter has a recess for a seal to protect the seal from corrosive gases and maintain an integrity of the seal. A gas source introduces a gas to the arc chamber body. A liner has an opening configured to pass the cathode shield therethrough, where the liner has a recess. A gap is defined between the U-shaped lip and the liner, wherein the U-shaped lip reduces a conductance of gas into the gap and the recess further reduces conductance of gas into the region.

A gas discharge lamp has an inner bulb with a discharge vessel with two sealing sections thereon, from which electrodes protrude into the discharge vessel, each electrically connected with a conductor in the associated sealing section to supply current to the electrodes. The lamp also has an outer bulb surrounding the discharge vessel, leaving a cavity therebetween. Close to at least one of the electrodes in or near a transitional area between the discharge vessel and the associated sealing section on an outside of the inner bulb is arranged potential-free a conductive structure which on application of a voltage to the electrodes influences the electrical field adjacent the electrodes such that a discharge arc travels from the electrode first in the direction of a wall section of the discharge vessel adjacent the electrode and then over the inside of the wall toward the other electrode.