What is the output of photomultiplier tube?
As Figure 6-1 shows, when light strikes the photocathode of a photomultiplier tube, photoelectrons are emitted. These photoelectrons are multiplied by the cascade process of secondary emission through the dyn- odes (normally 106 to 107 times) and finally reach the anode connected to an output processing circuit.
Why is a photomultiplier tube so sensitive?
Photomultipliers (sometimes called photon multipliers) are a type of photoemissive detectors which have a very high sensitivity due to an avalanche multiplication process, and also exhibit a high detection bandwidth.
How do you test a photomultiplier tube?
The PMTs are to be tested by flashing a very dim LED light in the dark box with them. The LED is activated using the lowest possible voltage to emit the smallest number of photons possible. The light flashes very quickly (at roughly 10 Hz) and remains lit for only 11ns at a time.
What are the characteristics of photomultiplier tube?
PMT characteristics that must be considered during the selection process include energy resolution (quantum efficiency), linearity, long- and short-term stability, electronic noise level, gain, photocathode uniformity, photocathode wavelength sensitivity, and PMT rise time.
Is a photomultiplier tube an amplifier?
A conventional PMT (Photomultiplier) is a vacuum tube which contains a photocathode, a number of dynodes (amplifying stages) and an anode which delivers the output signal.
How does photomultiplier tube works?
A photomultiplier tube, useful for light detection of very weak signals, is a photoemissive device in which the absorption of a photon results in the emission of an electron. These detectors work by amplifying the electrons generated by a photocathode exposed to a photon flux.
What are the two types of photomultiplier tube?
There are two common photomultiplier orientations, the head-on or end-on (transmission mode) design, as shown above, where light enters the flat, circular top of the tube and passes the photocathode, and the side-on design (reflection mode), where light enters at a particular spot on the side of the tube, and impacts …
How does a photomultiplier tube work?
Which sensor is used in photomultiplier tube?
3.3 Detector Photomultiplier tubes (PMTs) are generally used as the photodetectors because of their fast response, high gain, and high signal-to-noise ratio. They are sensitive for detection of light in the UV, visible, and near-IR region of ∼200–900 nm.
Is photomultiplier tube a sensor?
Photomultiplier tubes (photomultipliers or PMTs for short), members of the class of vacuum tubes, and more specifically vacuum phototubes, are extremely sensitive detectors of light in the ultraviolet, visible, and near-infrared ranges of the electromagnetic spectrum.
What is PMT Sensor?
The photomultiplier is an extremely sensitive light detector providing a current output proportional to light intensity. Photomultipliers are used to measure any process which directly or indirectly emits light. PMT is a well established technology.