Editing 4Pi (section)

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'''4Pi''' may refer to:
* [[IBM System/4 Pi]], a family of avionics computers
* [[4Pi microscope]], a microscope that uses interference and fluorescence computers
* 4×π = 12.56637..., the [[solid angle]] of a complete sphere measured in [[Steradian|steradians]]
* [[Hermetic detector]] (also called a 4π detector)

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