High-Intensity Lamps

The compound cerium oxide (either Ce Oj or CeO ) is used to coat the inside of ovens because it was discovered that food cannot stick to oven walls that are coated with cerium oxide. Cerium compounds are used as electrodes in high-intensity lamps and film projectors used by the motion picture industry. Cerium is also used in the manufacturing and polishing of high-refraction lenses for cameras and telescopes and in the manufacture of incandescent lantern mantles. It additionally acts as a chemical reagent, a misch metal, and a chemical catalyst. Cerium halides are an important component of the textile and photographic industries, as an additive to other metals, and in automobile catalytic converters. Cerium is also used as an alloy to make special steel for jet engines, solid-state instruments, and rocket propellants. 

Finally, heating can be done by irradiating the susceptor with high intensity lamps that will transmit readily through the fused quartz. 

The research at MIT has been done in the cold-wall vertical tube reactor shown in Figure 14. The wafer is aligned almost parallel to the flow on a vertical silicon carbide-coated susceptor. The wafer is heated by optical radiation from high-intensity lamps to a temperature of 775°C. Silane was introduced... 

In comparison to the Genus reactor, this system holds the wafer upside down to minimize any particulate on the wafer. Also, since this is a singlewafer machine, a loadlock is provided to ensure that the reaction chamber is never opened to the atmosphere. Attempts to provide this feature on a batch reactor are difficult and expensive, due to the size of the chamber needed. Heating is done in a way similar to the Genus system. High-intensity lamps shine on the back of a chuck to heat it to processing temperature. 

Sc High-intensity lamps, nuclear reactors China, US, Aus., Ind. 

It was recognized early on, in the development of high-intensity lamps, that pure quartz enveloped UV lamps produced ozone in unacceptable quantities. Most facilities using them, particularly for fluorescence spectroscopy, were required to... 

The use of hollow cathode lamps is sufficient for the majority of elements. The low intensity and short service life of these lamps when used for volatile elements such as As, Te, Se, Bi, etc. may, however, be a problem when determining traces of these elements. Electrodcless lamps or high intensity lamps (with auxiliary hot cathode) can be used in these cases to enhance the quality of analysis of these elements. 

O The spiral-wound high-intensity lamp flashes, supplying energy to the helium-neon gas mixture inside the tube. The atoms of the gas absorb the light energy and are raised to an excited energy state. 

UV lamp is the most crihcal element in the disinfection. The most widely used UV lamps can be classihedinto low-pressure low-intensity lamp, low-pressure high-intensity lamp, medium-pressure high-intensity lamp, high-pressure high-density lamp, and other types of lamps. The details of the typical lamps are listed in Table 3. The low-pressure mercury lamp works in an internal pressure range of 0.001-0.1 torr. Mercury is typically... 

For multilamp photo reactors to handle large capacity, about 200-500 lamps can be replaced by one 30 kW medium-pressure high-intensity lamp at the same operating cost, but with much lower volume. However, systems with medium-pressure lamps require an efficient cooling system to maintain the desired reactor temperature. For UV/ozone AOP, ozone dissolution is enhanced by efficient design of the diffusers to improve the mass transfer. 

Hollow-cathode lamps for about 70 elements are available from commercial sources. For certain elements, high-intensity lamps are available. These provide an intensity that is about an order of magnitude higher than that of normal lamps. Some hollow-cathode lamps are fitted with a cathode containing more than one element such lamps provide spectral lines for the determination of several species. The development of the hollow-cathode lamp is widely regarded as the single most important event in the evolution of atomic absorption spectroscopy. 

Place a high intensity uv radiation lamp close to the top of the azobenzene solution and turn on the lamp. The uv radiation provides energy to convert the tram form into the cis form. Note the time when this is begun. Irradiation for at least 30 minutes with a high intensity lamp is required. Check with your instructor for the time required with your lamp. 

When the azobenzene has been irradiated for about 30 minutes, shut off the lamp. NOTE the time will vary on this depending on the lamp intensity. Thirty minutes is based on a Hanovia high intensity lamp with a visible region filter. Be careful - the evaporating dish will be hot. Use a towel when you pick it up. 

Scandium is used as a neutron window or filter in nuclear reactors. Scandium compounds are used in high-intensity lamps. 

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