Glossary

A B C D E F G H I J K L M N O P Q R S T U V W X Y Z


А

Active area - maximum MCP output diameter, within which electron flow from a source falls on radiation detector.

Amplitude resolution(for quasi Gaussian amplitude) – pulse height distribution full width at half maximum to amplitude maximum ratio.

Anode(for quasi Gaussian amplitude) – collector element registrating electron flows generated by avalanche of multiplying system.


B

Bias angle – the angle between MCP channels centerlines and normal plane of MCP input surface.

C

Channel length-to-diameter ratio – MCP thickness to mean channel diameter ratio.

Channel diameters spread – value determinable as average deviation from predetermined number of channel diameters measurement results to average channel diameter ratio, expressed in percentage.

Channel electron multiplier – Electrostatic Secondary-Electron Multiplier having channel configuration (straight or curved tube with a rather long length) with continuous dynode system to the ends of which voltage is applied (usually several kV). Secondary electrons migration inside channel takes place under axial electric field action. Electrons accelerated by the field, striking the channel walls, produce secondary electron emission.

Charge saturation – MCP operating mode at extremely low input current (10-13 A/cm2), at which output pulse single electron distribution transforms from exponential to Gaussian (normal).

Chevron – two twin-tandem arranged MCPs separated/ not separated by a gap, with channel centerlines forming with respect to each other angle of ten or more degrees (depending on MCPs bias angles).

Center-to-center spacing (Pitch) – the distance between two adjacent MCP channels center points/

Collector – anode system, providing electron avalanche coordinate identification.

Coordinate-sensitive detector – detector which output signal carries information about particle incidence place with the detector.

Contact Electrode – MCP surface metal coating, providing contact (input or output) for channel secondary-electron multipliers.


D

Dark count rate density – dark count rate per unit area in unit time.

Dark current – the current produced by electron flow from MCP output when voltage is applied and input current is not applied.

Dark current density – MCP dark current to MCP operating area ratio.

Detection Efficiency –the probability of a particle incident on MCP input to be detected, and its ability to produce electron avalanche inside MCP channels.

Dynamic range – limiting realizable count rate.


E

Electron Image – electron flux density distribution at MCP output, observable on Phosphor Screen.

Electron image transfer – process at which electron flux density distribution from a source (for example photocathode) is reflected on the output surface of a detector by electric or electromagnetic field.

Electrostatic focusing – charged particles focusing by electrostatic field.


F

Fiber-optic element – optoelectronic element based on optical fibers.


G

Gain (MCP) – MCP output current to input current ratio.

Gain Factor of Coordinate-Sensitive Detector – most probable amplitude value of Coordinate-sensitive detector output pulses height distribution.


I

Image Intensifier Tube (IIT) – Photoelectron electro-vacuum device intended for image spectral composition enhancement or image intensification.


Input current – Current generated by electron flow incident on input surface of a MCP.


L

Limiting resolution– maximum number of clearly visible line pairs per 1 mm2 of an electron image produced by a MCP measured with a standard test chart, at optimal for observer input current and specified magnification of optical system, MCP voltage and field strength between MCP – phosphor screen.


M

MCP channel – each of the multitude of MCP separate secondary electron multipliers through holes.


“Memory effect” – the property of a MCP operating in non-linear region to retain electron image on MCP output after an object or its electron image is removed from MCP input.


Microchannel Plate – a set of identical regularly stacked channel secondary electron multipliers fused in a boule and sliced into discs, on the flange surfaces of which contact electrodes are deposited.


Modulation transfer function (MTF) of MCP - output unit system – functional relation of contrast transfer coefficient of system MCP – output unit to test chart spatial frequency with electron flux sinusoidal distribution.


N

Noise factor (F) – is to be calculated as follows:

F = (S/N)2in : (S/N)2out
Where: S – Signal, N – Noise


Nominal voltage of a MCP – Voltage at which specified MCP gain coefficient is provided.


O

Open Area Ratio – the open area of a MCP input surface to its overall area ratio.

Operating voltage – optimal operating voltage level of a MCP.

Outgassing – process of evacuation of contaminant gases from MCP surface and the material it is made of. Outgassing increases stability, reliability and operational life of a device, providing elimination of MCP gassing inside vacuum assembly.

Output current – current generated by electron flow from MCP output when input current and voltage are applied to MCP.


P

Particles detector – a device intended for elementary particles (protons, neutrons, electrons etc.), atomic nucleuses, x-ray and y - quantum registration.

Photocathode – a cold cathode emitting under optical irradiation electrons in vacuum and converting optical radiation to electron radiation.

Pulse Counting mode – signal registration by counting of electrons emitted from a photocathode or incident particles flows forming registrating image on the MCP input surface.

Pulse Height distribution – pulse number versus their amplitude.


R

Resolution – the ability of an Image Intensifier Tube or a Night Vision Device to distinguish small parts of transferred/ intensified image.

Resistance (R) – MCP voltage to MCP strip current ratio measured in vacuum when no input current is applied.


T

Thermostability – the ability of a MCP or a detector to withstand vacuum thermal processing.


Thickness of a MCP – the distance between input and output flanges of a MCP.


V

V- Stack – see Chevron.