Flood gun

With non-conductive materials, sputtering on the sample surface can ensure that more charged particles are brought onto the sample than are sputtered out when the material is bombarded with ions. This can lead to an excess charge.

A floodgun is an electromechanical instrument that is used in microscopy or in ToF-SIMS devices. It delivers a steady stream of low-energy electrons and directs them at a desired target, the so-called “flood area”. Floodguns usually function as secondary electron guns and are used for charge neutralization. The aim of this is to achieve better image quality.

The flood gun makes it possible to take high-resolution images even of poorly conducting or non-conducting samples. So the target itself is usually an area on an insulator or semiconductor in which another ion gun has just left a positive net charge.

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