Abstract: A lamp includes a discharge vessel. Tungsten electrodes extend into the discharge vessel. An ionizable fill is sealed within the vessel. The fill includes a buffer gas, optionally free mercury, a halide component which includes a rare earth halide selected from the group consisting of lanthanum halides, praseodymium halides, neodymium halides, samarium halides, cerium halides, and combinations thereof. A source of available oxygen is present in the discharge vessel. The rare earth halide is present in an amount such that, during lamp operation, in combination with the source of available oxygen, it maintains a difference in vapor phase solubility for tungsten species between a wall of the discharge vessel and at least a portion of at least one of the electrodes.

Abstract: A lamp includes a discharge vessel. Tungsten electrodes extend into the discharge vessel. An ionizable fill is sealed within the vessel. The fill includes a buffer gas, optionally free mercury, a halide component which includes a rare earth halide selected from the group consisting of lanthanum halides, praseodymium halides, neodymium halides, samarium halides, cerium halides, and combinations thereof. A source of available oxygen is present in the discharge vessel. The rare earth halide is present in an amount such that, during lamp operation, in combination with the source of available oxygen, it maintains a difference in vapor phase solubility for tungsten species between a wall of the discharge vessel and at least a portion of at least one of the electrodes.

Abstract: A lamp includes a discharge vessel. Tungsten electrodes extend into the discharge vessel. An ionizable fill is sealed within the vessel. The fill includes a buffer gas, optionally free mercury, a halide component which includes a rare earth halide selected from the group consisting of lanthanum halides, praseodymium halides, neodymium halides, samarium halides, cerium halides, and combinations thereof, a source of available halogen. The discharge vessel optionally includes a source of available oxygen. The source of available halogen and optional source of available oxygen are present in an amount such that the vapor phase solubility of tungsten species in the fill during lamp operation is lower adjacent at least a portion of one of the electrodes than at a wall of the discharge vessel, such that tungsten deposited on the wall during lamp operation is transported back to the electrode.

Abstract: Discharge tubes for a lamp include a body portion with a first end, a second end, and a tubular member defining an interior area. The tubular member extends along an elongated axis between the first end and the second end. The discharge tube further includes a first end portion provided at the first end of the body portion. The first end portion includes a first tubular extension having a first through passage in communication with the interior area. The first end portion further includes a first transition section connected between the first tubular extension and the body portion.

Abstract: Discharge tubes for a lamp include a body portion with a first end, a second end, and a tubular member defining an interior area. The tubular member extends along an elongated axis between the first end and the second end. The discharge tube further includes a first end portion provided at the first end of the body portion. The first end portion includes a first tubular extension having a first through passage in communication with the interior area. The first end portion further includes a first transition section connected between the first tubular extension and the body portion.

Abstract: Discharge tubes for a lamp include a body portion with a first end, a second end, and a tubular member defining an interior area. The tubular member extends along an elongated axis between the first end and the second end. The discharge tube includes a first end portion provided at the first end of the body portion. The first end portion includes a first tapered portion that is tapered in a direction extending substantially perpendicular from the elongated axis. The first tapered portion includes an interior surface facing the interior area. The tapered portion spans between a maximum extent in the direction of the elongated axis and a minimum extent in the direction of the elongated axis.