一门新的技术在现代的科学技术中,具有一定速度和方向的束状的电子流(电子束)的利用是相当普遍的。例如,X光管是利用定向的电子束轰击难熔的金属靶,而产生一定数量的X射线的;电视接收机是利用电子束打在荧光屏上,使荧光屏发光而显示出图象来的,电子显微镜是利用电子束穿透样品后放大成象的。利用电子束工作的仪器设备还有不少,当这些仪器调整不良或使用不当时,靶子或样品常常会由于受到电子束的强烈轰击而烧毁。这一个现象曾使科学工作者大伤脑筋。在 A new technology In modern science and technology, the use of bundled electron currents (electron beams) with a certain speed and direction is quite common. For example, an X-ray tube uses a directed electron beam to bombard a refractory metal target to generate a certain amount of X-rays; a television receiver uses an electron beam to hit a fluorescent screen to make the screen glow and display an image. Electron microscopy is the use of electron beams to penetrate the sample after magnification. There are many instruments and equipment that work with electron beams. When these instruments are improperly adjusted or improperly used, targets or samples are often burned due to the strong bombardment of electron beams. This phenomenon has caused scientists to use their brains. in