關於馬爾塔十字管的問題

Although an increasing voltage between the cathode and anode increases the kinetic energy of electrons, collisions between energetic electrons with air molecules casue ionization and excitation. These would greatly lose the energy of the electrons. The electrons, after multiple scatterings and collisions, no longer in the form of a beam and which could not cast a shadow of the Maltese Cross on the fluoresence screen.

馬爾塔十字管是研究電子束的特性的。
甘我唔系好明你講加強電勢差目的是什麽啊？
另外，保持真空是避免電子碰撞空氣分子而減速，使得實驗結果有所偏差。