Department of Radiation Oncology, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts.
Int J Radiat Oncol Biol Phys. 2013 Nov 1;87(3):555-61. doi: 10.1016/j.ijrobp.2013.06.2033.
The purpose of this article is to review briefly the nature of protons: creation at the Big Bang, abundance, physical characteristics, internal components, and life span. Several particle discoveries by proton as the experimental tool are considered. Protons play important roles in science, medicine, and industry. This article was prompted by my experience in the curative treatment of cancer patients by protons and my interest in the nature of protons as particles. The latter has been stimulated by many discussions with particle physicists and reading related books and journals. Protons in our universe number ≈10(80). Protons were created at 10(-6) -1 second after the Big Bang at ≈1.37 × 10(10) years beforethe present. Proton life span has been experimentally determined to be ≥10(34) years; that is, the age of the universe is 10(-24)th of the minimum life span of a proton. The abundance of the elements is hydrogen, ≈74%; helium, ≈24%; and heavier atoms, ≈2%. Accordingly, protons are the dominant baryonic subatomic particle in the universe because ≈87% are protons. They are in each atom in our universe and thus involved in virtually every activity of matter in the visible universe, including life on our planet. Protons were discovered in 1919. In 1968, they were determined to be composed of even smaller particles, principally quarks and gluons. Protons have been the experimental tool in the discoveries of quarks (charm, bottom, and top), bosons (W(+), W(-), Z(0), and Higgs), antiprotons, and antineutrons. Industrial applications of protons are numerous and important. Additionally, protons are well appreciated in medicine for their role in radiation oncology and in magnetic resonance imaging. Protons are the dominant baryonic subatomic particle in the visible universe, comprising ≈87% of the particle mass. They are present in each atom of our universe and thus a participant in every activity involving matter.
大爆炸时的产生、丰度、物理特性、内部组成和寿命。还考虑了一些质子作为实验工具的粒子发现。质子在科学、医学和工业中都发挥着重要作用。本文的灵感来自于我用质子对癌症患者进行治疗的经验，以及我对质子作为粒子的性质的兴趣。这种兴趣源于与粒子物理学家的多次讨论，以及阅读相关书籍和期刊。我们宇宙中的质子数量约为 10(80)。质子是在大爆炸后 10(-6) 到 1 秒之间产生的，大约在现在的 137×10(10)年前。质子的寿命已通过实验确定为≥10(34)年，也就是说，宇宙的年龄是质子最小寿命的 10(-24)。元素的丰度为：氢，约 74%；氦，约 24%；以及更重的原子，约 2%。因此，质子是宇宙中占主导地位的重子亚原子粒子，因为约 87%是质子。它们存在于我们宇宙中的每个原子中，因此参与了可见宇宙中物质的几乎所有活动，包括我们星球上的生命。质子于 1919 年被发现。1968 年，人们确定质子由更小的粒子组成，主要是夸克和胶子。质子已成为发现夸克（魅、底和顶）、玻色子（W(+)、W(-)、Z(0) 和希格斯玻色子）、反质子和反中微子的实验工具。质子在工业上的应用众多且重要。此外，质子在放射肿瘤学和磁共振成像中因其在辐射方面的作用而在医学上得到广泛应用。质子是可见宇宙中占主导地位的重子亚原子粒子，占粒子质量的约 87%。它们存在于我们宇宙中的每个原子中，因此参与了涉及物质的每一个活动。
