What is the output of photomultiplier tube?
Photomultiplier tubes typically utilize 1000 to 2000 volts to accelerate electrons within the chain of dynodes. (See Figure near top of article.) The most negative voltage is connected to the cathode, and the most positive voltage is connected to the anode.
What is gain in PMT?
The current gain of a PMT is a strong function of the high voltage applied to the PMT. Very often, PMTs will be operated well above the high voltage recommended by the manufacturer, and thus substantially higher current gains (10× to 100× above specs).
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.
How do you calculate PMT?
The format of the PMT function is:
- =PMT(rate,nper,pv) correct for YEARLY payments.
- =PMT(rate/12,nper*12,pv) correct for MONTHLY payments.
- Payment = pv* apr/12*(1+apr/12)^(nper*12)/((1+apr/12)^(nper*12)-1)
How do you calculate PMT on a calculator?
Payment (PMT)
- Enter 20000 and press the PV button.
- Enter 5 and then divide by 12. The result is 4.1666667 and then press the i% button.
- Enter 5 and then multiply by 12.
- The FV field should be 0, however even if a value is entered here it will be ignored.
- Press the Compute button and then the PMT button.
How many Dynodes are used in photomultiplier tube?
When a photon strikes the photocathode of the PMT, an electron is released, and the electron is directed toward the first of 10 dynodes by the bias voltage. At successive dynodes, each incoming electron ejects three or four more electrons, causing a multiplication of the current.
What makes up a photomultiplier tube ( PMT )?
Photomultiplier Tubes A photomultiplier tube (PMT) consists of a photosensitive cathode, several dynodes and a collection anode. The dynodes are responsible for the increase in signal by electron multiplication. PMTs see the elemental line intensity per unit time proportionally with current and have wide dynamic ranges.
What was the first mass produced photomultiplier tube?
The side-on design is used, for instance, in the type 931, the first mass-produced PMT. Besides the different photocathode materials, performance is also affected by the transmission of the window material that the light passes through, and by the arrangement of the dynodes.
What kind of voltage do you need for a photomultiplier?
For photomultiplier tube operation, a high voltage from 500 to 3000 volts is usually applied across the cathode (K) and anode (P), with a proper voltage gradient set up between the photoelectron focusing electrode (F), dynodes and, depending on tube type, an accelerating electrode (accelerator).
What makes up a photomultiplier vacuum tube?
A photomultiplier tube is a vacuum tube consisting of an input window, a photocathode, focusing electrodes, an electron multiplier and an anode usu- ally sealed into an evacuated glass tube. Figure 2-1 shows the schematic construction of a photomultiplier tube.