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Interstellar scintillation
| Glossary Of Laser Terminology |
Electromagnetic waves as they propagate though the interstellar media suffer frequency-selective fading. the resulting corrupted signal is said to undergo scintillation effects. the higher the modulation bandwidth the worse the effect.
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Interstellar communications, английский
Межзвездная связь
Interstellar dispersion, английский
The velocity of propagation of electromagnetic waves depends upon frequency. thus, unless the wave is highly monochromatic, the energy in the wave arrives at the receiver at differing times. this can severely limit the modulation bandwidth, since the process of modulating data onto an electromagnetic carrier wave broadens its bandwidth.
Scintillation, английский
- With respect to radiation protection , scintillation is the process where by a material will emit light photons when exposed to ionising radiation . the light photons can be measured with a photo-multiplier tube which will multiply the events to produce a
- This term is used to describe the rapid changes in irradiance levels in a cross section of a laser beam produced by atmospheric turbulence.
- The mirrorlike reflections a diamond’s facets make when it is turned while being exposed to light.
- Scintillation is the intense sparkle that comes from a diamond when it moves. black and white sparkles of scintillation show well in flood lit or office lighting environments where fire can be totally absent. under pin point or spot lights fire also adds to scintillation.
- Emission of light of specific frequencies after the absorption of electromagnetic radiation, such as x-rays or gamma rays.
Scintillation (rt), английский
A localized flash of light caused by a particle or photon of ionizing radiation incident on a fluorescent material.
Scintillation counter, английский
- Electronic logger, scintilla¬tion probe
- A device for counting atomic particles by means of tiny flashes of light (scintillations) which the particles produce when they strike certain crystals.
Scintillation detector, английский
Radiation measuring device based on a scintillating material.
Scintillation probe, английский
An electronic logging device consisting of a scintillation-type gamma ray detecting unit built into a container small enough to be lowered into a borehole.
Scintillator, английский
- A substance which produces a flash of light when struck by radiation
- Brand name of a scintillation counting device.
Scintillator (rt), английский
A substance that emits a localized flash of light when excited by an incident particle or photon of ionizing radiation.
Electromagnetic, английский
Modulation, английский
- Изменение характеристик несущей в соответствии с информативным сигналом
- Модуляция
- The process, or results of the process, whereby some characteristic of one signal is varied in accordance with another signal. the modulated signal is called the carrier. the carrier may be modulated in three fundamental ways: by varying the amplitude, called amplitude modulation; by varying the frequency, called frequency modulation; by varying the phase, called phase modulation.
- The process by which some characteristic (i.e., amplitude, phase) of one rf wave is
- The process by which some characteristic (i.e., amplitude, phase) of one rf wave is varied in accordance with another wave (message signal).
- The coding of information onto a carrier frequency. may use amplitude, frequency, phase, or time, plus many forms of on/off digital coding
- The ability to superimpose an external signal on the output beam of the laser as a control.
- The process by which the characteristic of one wave (the carrier) modifies another wave (the signal). examples include amplitude modulation (am), frequency modulation (fm), and pulse-coded modulation (pcm).
- N модуляция modul|e
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Diffraction limited, английский
Electromagnetic waves diffract around the edges of opaque objects, or on passing through or reflecting off a finite aperture, like a dish, lens or mirror. even if such a wave is perfectly collimated, so that the beam emitted is parallel, it will eventually spread out. the larger the aperture in relation to the wavelength, the smaller the beam spread. an electromagnetic beam is said to be "diffraction limited" when it is so collimated that it cannot be made more narrow in the near-field. receivers are also said to be "diffraction limited" when the energy is focused into the smallest possible spot size at the focal plane. an optical receiver that is not "diffraction limited" may be said to be a "light bucket" - it collects photons, but cannot concentrate them into a very small tightly focused spot.
Ultraviolet (uv) radiation, английский
Electromagnetic radiation with wavelengths between soft x-rays and visible violet light, often broken down into uv-a (315-400 nm), uv-b (280-315 nm) and uv-c (100-280 nm).
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