Глосарій

Activation energy / Енергія активації  
This is the energy required for a substance to perform a reaction. In the Arrhenius equation for calculating the speed of a chemical reaction, activation energy is used as an indicator for expressing how difficult it is for a chemical reaction to occur. The Arrhenius equation is used to calculate the LED service life and the like. The activation energy of LED degradation is obtained from the failure rate under several temperature conditions.

Amorphous /  Аморфний
Noncrystalline state having no definite form. For example, when a liquid or gaseous semiconductor is cooled and solidi- fied so rapidly that no crystals are formed, it becomes amorphous. In this state, the crystal structure has a short-distance order but does not have a long-distance order, and a tail level appears at the band gap edge, making the optical characteristics different from those of monocrystalline or polycrystalline materials.

Anisotropic etching /  Анізотропне травлення       
An etching process in which the etching speed in a particular direction is different from that in other directions. For example, when a (100) silicon substrate is wet-etched using alkaline solution, V-grooves are formed due to the fact that the etching speed on the (100) plane is faster than that on the (111) plane. Etching in which the etching speed is the same in all directions is called isotropic etching.

Anodic bonding /  Анодний зв'язок      
When the flat surface of glass containing alkali metal is attached to the flat surface of silicon and heated while a voltage is being applied, an electrostatic attractive force is generated at the interface between the glass and silicon. Anodic bonding is the bonding technique that makes use of this phenomenon. During anodic bonding, the silicon side is used as the anode.

Anode luminous sensitivity /  Анодна світлова чутливість
Anode luminous sensitivity is the anode output current (amplified by the secondary emission process) per incident light flux (10^-10 to 10^-5 lumens) on the photocathode. A tungsten filament lamp, operated at a distribution temperature of 2856K, is used to provide the incident light. Cathode and anode luminous sensitivity are particularly useful when comparing tubes having the same or similar spectral response.
Anode luminous sensitivity is expressed in A/lm (amperes per lumen). Note that the lumen is a unit used for luminous flux in the visible region and therefore these values may be meaningless for tubes that are sensitive beyond the visible light region.    

The equation (see below) describing the temperature dependence of chemical/physical reaction speeds, proposed by S. A. Arrhenius (Sweden) in 1889. This equation is used to calculate the expected life of a component when a major cause of degradation of the component is probably temperature.

K = A exp (-Ea/k T)
K: reaction speed
A: constant
Ea: activation energy [eV]
k: Boltzmann’s constant [eV/K]

ASE (amplified spontaneous emission) / Підсилене спонтанне випромінювання
An optical amplifier amplifies signal light by induction radiation. However, it emits energy little by little even under conditions where no signal light is input. This is optical amplifier spontaneous emission and is referred to as ASE. This ASE is noise and degrades characteristics.    

Average/typical life (Lamp) / Середній/типовий термін використання (Лампа)
Length of time the lamp usually operates to with 50% of stated specifications, including output energy, drift and fluctuations. Using a lamp with a longer life leads to the reduction of maintenance cost as well as the time and running cost of equipment. Due to unique electrode structures with minimum electrode wear, Hamamatsu lamps feature unprecedented high stability over extended periods of operating time