Xenon flash lamp being fired. (See below for animated version)

A xenon flash lamp is an electric glow discharge lamp designed to produce extremely intense, incoherent, full-spectrum white light for very short durations. Image File history File links Xenon-flash. ... now. ... Coherence is the property of wave-like states that enables them to exhibit interference. ...

Construction

U-shaped Xenon Flash Lamp

The lamp comprises a sealed tube, often made of fused quartz, which is filled with a mixture of gases, primarily xenon, and electrodes to carry electrical current to the gas mixture. Additionally, a high voltage power source is necessary to energize the gas mixture; this high voltage is usually stored on a capacitor so as to allow very speedy delivery of very high electrical current when the lamp is triggered. Image File history File links This is a lossless scalable vector image. ... Image File history File links This is a lossless scalable vector image. ... General Name, Symbol, Number xenon, Xe, 54 Chemical series noble gases Group, Period, Block 18, 5, p Appearance colorless Standard atomic weight 131. ... Capacitors: SMD ceramic at top left; SMD tantalum at bottom left; through-hole tantalum at top right; through-hole electrolytic at bottom right. ... In electricity, current is the rate of flow of charges, usually through a metal wire or some other electrical conductor. ...

The glass envelope is most commonly a thin tube, which may be straight, or bent into a number of different shapes, including helical, "U" shape, and circular (to surround a camera lens for shadowless photography - 'ring flashes'). The electrodes protrude into each end of the tube, and are connected to a capacitor that is charged to a relatively high voltage. This is usually between 250 and 2000 volts, depending on the length of the tube, and the specific gas mixture. A photographic lens (or more correctly, objective) is an integrated system comprising one or more simple optical lens elements, used for a camera or microscope. ... Photography [fәtɑgrәfi:],[foʊtɑgrәfi:] is the process of recording pictures by means of capturing light on a light-sensitive medium, such as a film or sensor. ... Capacitors: SMD ceramic at top left; SMD tantalum at bottom left; through-hole tantalum at top right; through-hole electrolytic at bottom right. ... Josephson junction array chip developed by NIST as a standard volt. ...

Operation

A flash is initiated by first ionizing the gas mixture, then sending a very large pulse of current through the ionized gas. Ionization is necessary to decrease the electrical resistance of the gas so that a pulse measuring as much as thousands of amperes can travel through the tube. The initial ionization pulse may be generated by a tesla coil. A short high voltage peak produces the first ions at the sharp tip of the cathode (the housing is grounded). By applying radio frequency voltage the ions do not need to reach the anode, but couple capacitively to the housing (and the anode). This may be enhanced by putting a metal band onto the glass or a wire that is wrapped around the glass tube or by using water cooling, since water has a high dielectric constant and if ionized also conducts. When this current pulse travels through the tube, it excites electrons surrounding the xenon atoms causing them to jump to higher energy levels. The atoms' electrons immediately drop back to a lower orbit, producing photons in the process. Depending on the size and application of the flashlamp, xenon fill pressures may range from a few kilopascals to tens of kilopascals (0.01–0.1 atmosphere or tens to hundreds of torr). For low electrode wear the electrode needs to be at high temperature for the thermionic emission of electrons. ion (disambiguation) An ion is an atom or group of atoms with a net electric charge. ... Pulsed power is the science and technology of accumulating energy over a relatively long period of time and releasing it very quickly. ... Electrical resistance is a measure of the degree to which an electrical component opposes the passage of current. ... Current can be measured by a galvanometer, via the deflection of a magnetic needle in the magnetic field created by the current. ... Tesla Coil at Questacon, the Australian National Science Centre museum A Tesla coil is a type of resonant transformer, named after its inventor, Nikola Tesla. ... Also known as Fowler-Nordheim tunneling, field emission is a form of quantum tunneling in which electrons pass through a barrier in the presence of a high electric field. ... Diagram of a copper cathode in a Daniells cell. ... It has been suggested that this article or section be merged with Radio waves. ... The relative dielectric constant of a material under given conditions is a measure of the extent to which it concentrates electrostatic lines of flux. ... Properties The electron (also called negatron, commonly represented as e−) is a subatomic particle. ... The pascal (symbol Pa) is the SI unit of pressure. ... Standard atmosphere (symbol: atm) is a unit of pressure. ... For the standard botanical author abbreviation Torr. ... Thermionic emission (archaically known as the Edison effect) is the flow of electrons from a metal or metal oxide surface, caused by thermal vibrational energy overcoming the electrostatic forces holding electrons to the surface. ...

Output spectrum

As with all ionized gases, xenon flash lamps emit light in various spectral lines. This is the same phenomenon that gives neon signs their characteristic color. However, for xenon, there are enough spectral lines, and they are distributed across the spectrum in such a way, that to the human eye the light appears mostly white. The spectral profile of a xenon arc peaks in the green range, which is well matched to many applications involving visible light. This is the primary motivation for selecting xenon as a filler in spite of its high cost; krypton is also occasionally used, although it is even more expensive. Krypton has much greater output in the near-IR range, which is better matched to the absorption profile of Nd:YAG laser media than xenon emissions. A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ... Neon signs are often used to advertise for hotels, bars and entertainment venues. ... White is the combination of all the colors of the visible light spectrum. ... General Name, Symbol, Number krypton, Kr, 36 Chemical series noble gases Group, Period, Block 18, 4, p Appearance colorless Standard atomic weight 83. ...

During normal operation in most photographic-type systems, the spectral component of a flashlamp's emission is overshadowed by blackbody radiation. The proportion of light produced by spectral action compared to thermal action depends on current density in the arc. Higher current densities favor blackbody radiation over spectral radiation. For this reason, many laser systems intentionally utilize lower current densities than photographic flashes since more narrow spectral lines are usually favorable for pumping lasers, while a broadband output is better for photographic purposes. Production of greenish blue light instead of pure white is a clear indication of low-current density operation.

The flashlamps used on the National Ignition Facility laser are truly massive, the largest ever in commercial production.

image of NIF flashlamps from http://www. ... image of NIF flashlamps from http://www. ... A construction worker inside NIFs 10 meter target chamber. ...

Intensity and duration of flash

For short pulses the number of emitted electrons from the cathode is the limit. For longer pulses or continuous operation the cooling is the limit. Discharge durations for common flashlamps are in the microsecond to a few milliseconds range and can have repetition rates of hundreds of hertz. To help compare orders of magnitude of different times this page lists times between 10−6 seconds and 10−5 seconds (1. ... One millisecond is one-thousandth of a second. ... MHZ redirects here. ...

The flash that emanates from a xenon flash lamp may be so intense that it can ignite flammable materials within a short distance of the tube. Carbon nanotubes are particularly susceptible to this spontaneous ignition when exposed to the light from a flashtube.^[1] Similar effects may be exploited for use in aesthetic or medical procedures known as Intense Pulsed Light (IPL) treatments. IPL can be used for treatments such as hair removal and destroying lesions or moles. An electronic device known as a diode can be formed by joining two nanoscale carbon tubes with different electronic properties. ... Skin lesions caused by Chickenpox A lesion is any abnormal tissue found on or in an organism, usually damaged by disease or trauma. ... A mole, technically known as a melanocytic naevus, is a small, dark spot on human skin. ...

Applications

Because the duration of the flash that is emitted by a xenon flash tube can be accurately controlled, and due to the high intensity of the light, xenon flash lamps are most commonly used as photographic strobe lights. Xenon flashlamps are also used in the technique of very high speed or "stop-motion" photography, which was pioneered by Harold Edgerton in the 1930s. Photography [fәtɑgrәfi:],[foʊtɑgrәfi:] is the process of recording pictures by means of capturing light on a light-sensitive medium, such as a film or sensor. ... An animation illustrating the effect of strobe light A strobe light or stroboscopic lamp, commonly called a strobe, is a device used to produce regular flashes of light. ... Shadowgraph of a . ... Face The 1930s (years from 1930–1939) were described as an abrupt shift to more radical and conservative lifestyles, as countries were struggling to find a solution to the Great Depression, also known in Europe as the World Depression. ...

Due to their high-intensity and relative brightness at short wavelengths (extending into the ultraviolet) and short pulsewidths, flashlamps are also ideally suited as light sources for pumping atoms in a laser to excited states where they can subsequently be stimulated to emit coherent monochromatic light. Proper selection of the filler gas is crucial here, so the maximum of radiated output energy is concentrated in the bands that are the best absorbed by the lasing medium; eg. krypton flashlamps are more suitable than xenon flashlamps for pumping Nd:YAG lasers, as krypton emission in near infrared is better matching to the absorption spectrum of Nd:YAG. The wavelength is the distance between repeating units of a wave pattern. ... “UV” redirects here. ... Laser pumping is the act of energy transfer from an external source into the laser gain medium. ... Experiment with a laser (US Military) In physics, a laser is a device that emits light through a specific mechanism for which the term laser is an acronym: Light Amplification by Stimulated Emission of Radiation. ... A laser system generally consists of three important parts: An energy source (usually referred to as the pump or pump source); A gain medium or laser medium; A mirror, or system of mirrors, forming an optical resonator. ...

Xenon flash lamps have been used to produce an intense flash of white light, some of which is absorbed by Nd:glass that produces the laser power for inertial confinement fusion. In total about 1 to 1.5% of the electrical power fed into the flash tubes is turned into useful laser light for this application. General Name, Symbol, Number neodymium, Nd, 60 Chemical series lanthanides Group, Period, Block n/a, 6, f Appearance silvery white, yellowish tinge Standard atomic weight 144. ... Inertial confinement fusion using lasers rapidly progressed in the late 1970s and early 1980s from being able to deliver only a few joules of laser energy (per pulse) to a fusion target to being able to deliver tens of kilojoules to a target. ...

Animation

Xenon flash lamp being fired.

Wikipedia does not have an article with this exact name. ... Wikipedia does not have an article with this exact name. ...

References

1. ^ http://news.rpi.edu/update.do?artcenterkey=383&setappvar=page(1)

• Timing electronics can trigger multiple flashes and then activate a Q-switch

See also

• Strobe light
• Flash (photography)
• List of light sources

Lighting and Lamps v • d • e
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