point spread function

When light transferred from incident electrons by a thin fluorescent material is detected with CCD, the size of the emitted light is larger than that of the incident electrons due to scattering of electrons by the fluorescent particles. The size of the light can be larger than one pixel size of the CCD (～15 μm). The function that expresses the spread is called "point spread function." As a guide example, the intensity at the nearest pixel is about 1/3 of that of central pixel.