What is the significance of the discovery of "neutron"?

1932 in February, when the British physicist chadwick read about Iorio? When the Curies wrote a paper about "bombarding beryllium with A particles will produce uncharged particles with strong penetrating power", they were keenly aware that it was wrong to explain this phenomenon with Compton effect of strong gamma rays. So, he repeated their experiments and successively irradiated several elements with different weights with this kind of ray. The results proved that this kind of ray is really not gamma ray: because the lower the density, the easier it is to be absorbed, unlike gamma ray, which is easily absorbed by dense substances; Moreover, this ray will bounce back when it bombards the hydrogen nucleus, indicating that it is a neutral particle flow with a certain mass. By measuring the momentum of recoil nucleus and using the law of conservation of momentum, chadwick estimated that the mass of recoil nucleus is almost the same as that of proton. At this point, chadwick combined intuitive knowledge, logical thinking and experimental research, and boldly pointed out that this kind of beryllium radiation was the "neutron" that Rutherford had predicted and he had been looking for for for a long time. 1932 February 17, chadwick announced the discovery of "neutron".

The discovery of neutrons is a milestone in the history of nuclear physics, which has epoch-making and far-reaching significance. It is already clear that the nucleus is composed of protons and neutrons; Re-understand the relationship between atomic weight and atomic number, as well as nuclear characteristics such as spin and stability; More importantly, it opened the door for mankind to enter the era of atomic energy. Therefore, chadwick won the 1935 Nobel Prize in Physics.

Although neutrons date back to Aurio 193 1 year? The Curies were observed when studying natural radioactivity, but because of their contempt for theoretical research, they didn't believe Rutherford's idea of neutrons mentioned in his speech on 1920. In the end, they only regarded this phenomenon as Compton effect caused by intense gamma rays and missed the opportunity to find neutrons first. On the road of science, we must not give up any "abnormal" phenomenon easily, perhaps it is just a door to success.