Ultraviolet light is generated in the mercury discharge tube: a quartz tube containing two electrodes and an insulator suspended in an inert gas called mercury vapor. Mercury reaches its highest point at 254 nanometers, 310 nanometers and 366 nanometers, producing radiation between 200 and 400 nanometers. Quartz cuts off lower wavelengths and does not transmit any radiation below 230 nanometers.
Each atom consists of a nucleus with many electrons floating in a fixed orbit around it. By increasing the energy (electricity) electrons are brought in a higher orbit. Each element shows a tendency to return to its original state. The electron will retreat in its previous orbit: the excess energy is emitted as a photon. The most commonly used ultraviolet lamps are made by pressurizing dielectric mercury arc lamps or MPMA lamps. It can be produced in lengths ranging from a few millimeters to more than 2 meters. The life span of these lamps varies from 1000 to 2500 hours. The lamp tube is made of quartz because it is the only material that transmits ultraviolet light while enduring high temperatures of 6 to 800°C. The tubes will expand slightly and do have a high melting temperature (1100°C). The electrodes are made of tungsten: the process of producing them is extremely complicated. Tungsten is used because the temperature of the curve can be increased to more than 3000°C. The molybdenum plate is used to connect the electrode and the wire, which can expand together with the quartz. And it can still tolerate high voltage when heated. The lamp is finally suspended to a ceramic (or other) insulator. Because the supply current is often insufficient to power an MPMA lamp, a transformer is usually used for UV lamps.
Two types will be used: induction and repaired power transformers. Standard ballast is also used up to 5 kW capacity.
