為何X光的最短波長與X光管的電壓有關?

2011-01-11 9:55 am
在X光管內產生的X光,它的光譜有線狀部分和連續的部分。

以我所知,線狀部分的構成是由於高速電子完全撞飛了金屬原子最內層的電子(ionized)所導致,也就是說,高速電子的動能已經不少於鎢原子在基能的電離能,在接近第無限能量層的電子返回基態時所釋放出來的光子(X光)已經能對應它的最短波長,能量無限接近電離能。

假若加速電壓再提高一兩倍,X光光子的最短波長又會再短一些,這表示X光光子中最高的能量能夠再繼續增大嗎?大過電離能?為什麼呢?

更新1:

天同: How do the bombarding electrons convert all their energy into X-ray in this process?

回答 (2)

2011-01-11 7:59 pm
✔ 最佳答案
An x-ray spectrum composes of a continuous background and spectral lines that are characteristics of the target element.

The shortest wavelength refers to the shortest wavelength produced in the continuous background. It is produced because of rapid decceleration of fast moving electrons when they collide with heavy atoms in the target, such that all kinetic energy of an electron is transformed into electromagentic radiation. . The radiation so produced is called bremsstrahlung (i.e. braking radiation).

Be aware that the wavelengths of the characteristic spectral lines do not depend on the high tension used on the X-ray tube (i.e. independent of bombarding electron energy). They only depend on the target material.
2011-01-16 1:50 am
天同:
How do the bombarding electrons convert all their energy into X-ray in this process?


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