What is the quantum efficiency of a photocathode?
Some photocathode materials (see below) reach quantum efficiencies of more than 30% in some spectral region, while others (particularly those for the infrared) are limited to the order of 10% or even substantially lower.
Is photocathode positive or negative?
Photocathodes are also commonly used as the negatively charged electrode in a light detection device such as a photomultiplier or phototube.
What is the difference between photomultiplier and photodiode?
Following are the major difference between photodiode and photomultiplier tube. ➨Photodiode convert one photon into one electron, while photomultiplier amplify electrons. Photomultiplier tube uses detector which changes photons into electrons so that they can be detected.
What is Photocathode made of?
Photocathodes are typically made of alkali-metal films such as potassium bromide (KBr), cesium telluride (CsTe), cesium iodide (CsI), or rubidium telluride (RbTe).
What is maximum quantum efficiency?
It is defined as the number of signal electrons created per incident photon. In some cases it can exceed 100% (i.e. when more than one electron is created per incident photon).
What is photocathode made of?
What is photocathode response?
Photocathode sensitivity is a measure of how well the image intensifier tube converts light into an electronic signal so it can be amplified. This criterion specifies the number of electrons released by the Photocathode (PC). PC response is always measured in isolation with no amplification stage or ion barrier (film).
Where are photomultipliers used?
Photomultipliers are used in research laboratories to measure the intensity and spectrum of light-emitting materials such as compound semiconductors and quantum dots. Photomultipliers are used as the detector in many spectrophotometers.
What are Dynodes made of?
The dynode is made of a metal plate containing a substance on the surface such as a bialkali compound, which emits secondary electrons upon impact with accelerated electrons. The acceleration of the photoelectrons and the impact of these on the dynode produce multiple secondary electrons.