When high-energy X-rays having an energy higher than the binding energy of electrons in the inner layers of atoms collide with atoms, an inner electron is ejected and a hole is formed, making the whole atomic system unstable and more excited Condition. The atomic lifetime is about (10)-12-(10)-14s and then spontaneously transitions from a high-energy state to a low-energy state.
This process is called the relaxation process and the relaxation process can be either a radiative transition or a radiative transition.
When the electrons in the outer layer jump to the hole, the released energy is absorbed in the atom and expels another secondary photoelectron in the outer layer, also known as the Russian Intermittent Die ejected secondary photoelectrons are called secondary photoelectric effect or nothingcalled radiant effect and called Auger electrons. Its energy is characteristic and independent of the energy of the incident radiation.
When the electrons in the outer shell jump into the inner hole, the released energy is not absorbed in the atom but released in the form of radiation that produces X-ray fluorescence whose energy is equal to two. The energy difference between energy levels. Therefore, the energy or wavelength of X-ray fluorescence is distinctive and has a one-to-one correspondence with the elements.
After the K-layer electrons are ejected, the holes can be filled by any electrons in the outer layer, creating a series of spectral lines called the K-family spectral lines < / p>
The X-rays emitted from the L layer to the K layer are called Kα rays, and those emitted from the M layer to the K layerX-rays emitted are called Kβ rays... p>
Similarly, the electrons of the L layer are ejected to produce L-system radiation. When the incident X-rays excite the electrons of the K layer of an element into photoelectrons, and then the electrons of the L layer jump to the K layer, energy ΔE is released at this time, and ΔE = EK-EL. This energy is released in the form of X-rays, which produce Kα rays, as well as Kβ rays, L-series rays, etc.
H.G. Moseley (H.G.Moseley) found that the wavelength λ of fluorescent X-rays is related to the atomic number Z of the element and the mathematical relationship is as follows:
λ=K(Z-s)-2 This is Mosley's law, where K and S are constants. Thus, as long as the wavelength of the fluorescent X-rays is measured, the type of element can be known which is the basis of the qualitativen analysis of fluorescent X-rays. In addition, there is a certain correlation between the intensity of fluorescent X-rays and the content of corresponding elements. Accordingly, quantitative analysis of elements can be performed.