Step-By-Step Photomultiplier Selection Guide 

Step 1 - What is the wavelength of your source?

The following photocathodes are used in Electron Tubes photomultipliers. The quoted wavelength ranges refer to standard borosilicate windows.

Bialkali (K - Cs - Sb), 280-630 nm
Offers high blue and good green response with low dark current.

Rubidium Bialkali (Rb - Cs - Sb), 280 - 680 nm
Offers high blue and enhanced green response but twice the dark current of the bialkali.

Multialkali S20 (Na - K - Cs - Sb), 280 - 850 nm
Sensitivity extends ffrom the uv to the infrared but may require cooling to reduce dark curent.

High Temperature Bialkali (Na - K - Sb), 280 - 630 nm
Recommended for high temperature operation at temperatures above 60 °C.

Solar Blind (KBr, Csl, RbTe, CsTe), 110 - 360 nm
When sensitivity in the UV and VUV only is required.

Step 2 - Do you want to detect at wavelengths below 300 nm?

Window materials used in Electron Tubes photomultipliers are:

Borosilcate Glass
This is the standard, low cost, window material and is suitable for wavelengths greater than 300 nm.

UV glass (W)
Extends sensitivity down to 185 nm.

Quartz (Q)
Made from fused silica, this material transmits down to 160 nm.

Magnesium Fluoride (MgF2)
Transmits UV radiation down to 110 nm.

Step 3 - Is low background glass an advantage?

Step 4 - What detection area and geometry do you require?

Step 5 - Are high light levels or low temperature a consideration?

Step 6 - Have you considered signal / background?

Step 7 - What is the optimum photomultiplier gain?

Step 8 - Which dynode structure best meets your performance needs?

Step 9 - Are you operating in a harsh environment?

Step 10 - Which mechanical configuration for the base is best for you?