# Why does a single X-ray photon generate 1620 electrons when it hits CCD detector?

It emits X ray photons : mainly k-alpha & k-beta lines.

Why does a single X-ray photon generate 1620 electrons when it hits CCD detector ?

While, in photo-electric effect, single photon generates single electron i.e. a photo-electron.

• There are several different types of CCD detectors used with x-rays. You'll need to provide us with details about the type of detector you are referring to. Possibly you could link the article where that figure of 1620 electrons is given. – John Rennie Mar 27 at 12:02
• The x-ray creates one highly energetic electron. Through electron-electron scattering, that energetic electron creates the other thousand-odd electrons as it relaxes down to the conduction band edge. – Jon Custer Mar 27 at 12:51

Edit: Just to be clear to OP, as Jon Custer mentioned the initial process is a single excited electron (i.e. leading order absorption $$H_{int} \sim \mathbf{p}\cdot\mathbf{A}$$ term), but the lifetime of this electron is so short that it creates more excited electrons almost immediately (within attoseconds).