An arc lamp includes an arc tube configured to receive a reaction gas therein, and an anode and a cathode disposed opposite one another within the arc tube and configured to generate an electrical arc. The anode includes an anode head portion extending inwardly from an end portion of the arc tube, and an anode tip portion bonded to the anode head portion and comprising a trench extending in a top surface along a peripheral region of the anode tip portion.

An arc lamp includes an arc tube configured to receive a reaction gas therein, and an anode and a cathode disposed opposite one another within the arc tube and configured to generate an electrical arc. The anode includes an anode head portion extending inwardly from an end portion of the arc tube, and an anode tip portion bonded to the anode head portion and comprising a trench extending in a top surface along a peripheral region of the anode tip portion.

A system, method, and computer program product for optimizing the cooling of a UV bulb during a UV irradiation process is described. A power level in which to operate the UV bulb is received. In addition, a particular type of UV bulb being used in the UV irradiation process is received. Thereafter, at least one optimal UV cooling parameter that corresponds to the power level and the type of UV bulb is retrieved from a UV source parameters database. At least one control signal is then sent to a cooling device that is based on the retrieved optimal UV cooling parameter, and the control signal instructs the cooling device to cool the particular type of UV bulb according to the retrieved optimal UV cooling parameter during the UV irradiation process.

Sulfur arc lamp includes an arc chamber that has a cathode and an anode both made of refractory metals that include pure tungsten, pure molybdenum, tungsten alloy, molybdenum alloy or a composite in which tungsten is at least 90%, or a composite in which molybdenum is at least 90%; a plasma initiation gas filling the plasma chamber; power supply configured to switch on and off electric arc discharge between the cathode and anode; second chamber connected to the arc chamber for releasing sulfur vapor into the plasma arc chamber, thereby creating a sulfur-containing plasma gas when the discharge occurs, and configured to selectively remove the sulfur vapor from the sulfur-containing plasma gas when the discharge occurs, wherein the second chamber is configured to reduce a concentration of the sulfur vapor in the arc chamber below 10.sup.13 molecules per cm.sup.3 before the electric arc discharge is off.

There is described In another of its aspects, the present invention provides a radiation source assembly comprising: (i) an elongate radiation source; (ii) a positioning element connected to a proximal portion of the elongate radiation source; and (iii) a connecting portion secured to a proximal portion of the positioning element and configured to engage a support element to maintain a distal portion of the elongate radiation source in a cantilevered position. The present radiation source assembly is configured such that the distal portion of the radiation source is cantilevered with the respect to the distal portion of the protective sleeve in which it is disposed. This feature obviates the need to use spacers, stops, springs and the like in a distal portion of the protective sleeve to maintain correct position of the radiation source within the protective sleeve. Further, the present radiation source assembly is advantageous in that allows for withdrawal of the radiation source from the radiation source assembly without the need to disengage all of the components. Thus, it is possible to replace a single radiation source by removing it from the protective sleeve during operation of the fluid treatment system. This operation can be accomplished quickly without the need to shut down the fluid treatment system or otherwise compensate for the fact that one of the radiation source is being serviced.

A cathode-ray tube ultraviolet light source includes a metal housing provided with a light-transmissive window, a heatsink disposed within the metal housing, a phosphor having a first surface and an opposing second surface, wherein the second surface of the phosphor is in thermal contact with the heatsink, and an electron gun capable of developing an electron beam to impinge upon the first surface of the phosphor, whereby light emitted from the second surface of the phosphor is directed through the light-transmissive window.

The present invention provides a safe ultraviolet light irradiation device that uses ultraviolet light safe to the human body and has a wide range of microorganism elimination and sterilization effects, and also provides an ultraviolet light emitting element provided with: an electrode substrate having a pair of electrodes; at least one cylindrical or flattened cylindrical glass tube disposed on the electrode substrate so as to face both of the electrodes, the glass tube having both end parts sealed; a xenon gas-containing discharge gas enclosed inside the glass tube and generating an electric discharge due to a voltage applied to the electrodes; and a phosphor layer formed on an inner surface of the glass tube and emitting light when excited by the electric discharge, wherein the glass tube is made of borosilicate glass or quartz glass; and the phosphor layer is made of a phosphate-based fluorescent material and has an emission spectrum having a peak half value width within a wavelength range of 50 nm or less with a peak at a wavelength of 20310 inm on an illuminance basis.

A cathode-ray tube ultraviolet light source includes a metal housing provided with a light-transmissive window, a heatsink disposed within the metal housing, a phosphor having a first surface and an opposing second surface, wherein the second surface of the phosphor is in thermal contact with the heatsink, and an electron gun capable of developing an electron beam to impinge upon the first surface of the phosphor, whereby light emitted from the second surface of the phosphor is directed through the light-transmissive window.

A light-emitting plasma lamp bulb for solar ultraviolet simulation includes a bulb cover having a spherical shape or a rod shape through which ultraviolet rays are transmittable, discharge gas contained in the bulb cover, and a first light-emitting material and a second light-emitting material, wherein the first light-emitting material includes at least one of mercury (Hg) and mercury iodide (HgI.sub.2), and the second light-emitting material includes sulfur (S.sub.8), wherein light emitted from the bulb has a maximum optical power intensity in a range of 395 to 455 nm which is an ultraviolet-visible boundary region, wherein, when compared using a same ultraviolet dose in an ultraviolet region of 290 to 400 nm, an integrated intensity of a visible and infrared region of 400 to 850 nm is equal to or less than of an integrated intensity of a visible and infrared region of a standard solar spectrum (ASTM G173, AM 1.5G).