proton, one of the three basic subatomic particles—along with neutrons and electrons—that make up atoms, the basic building blocks of all matter and chemistry. It is the positively charged particle that, together with the electrically neutral particles called neutrons, make up the nucleus of an...
In nuclear fission the nucleus of anatombreaks up into two lighter nuclei. The process may take place spontaneously in some cases or may beinducedby the excitation of the nucleus with a variety of particles (e.g., neutrons,protons,deuterons, or alpha particles) or withelectromagnetic radiationin...
The sugar-peptide interaction is likely rooted in evolutionary mechanisms and one could reasonably speculate regarding its role in the origin and transmission of homochiral sequences. Furthermore, carbohydrate architectures are as diverse as peptide and enzymes tailored for multiple functionality. Sugars ...
He performed the beryllium bombardment experiments himself and interpreted that radiation as being composed of particles of mass approximately equal to that of the proton but without electrical charge—neutrons. That discovery provided a new tool for inducing atomic disintegration, since neutrons, being ...
Electrons extracted from a glowing filament may be used to ionize gases. This is the basis for the electron bombardment ion source (seeFigure 1). A satisfactory electrode arrangement enables the production of a beam of ions much more nearlyhomogeneousin energy than with the arc, greatly simplifyi...
1911Wilhelm WienGermanydiscoveries regarding laws governing heat radiation 1912Nils DalénSwedeninvention of automatic regulators for lighting coastal beacons and light buoys 1913Heike Kamerlingh OnnesNetherlandsinvestigation into the properties of matter at low temperatures; production of liquid helium ...
(LHC), designed to collide proton beams at an energy of almost 7 teraelectron volts (TeV) per beam. The LHC, which extended the reach of high-energy physics experiments to a new energy plateau and thus revealed uncharted areas of study, began test operations in 2008. In 2012 CERN ...
Most of the particle accelerators used in medicine and industry produce a beam of particles for a specific purpose—for example, for radiation therapy or ion implantation. This means that the particles are used once and then discarded. For many years the same was true for accelerators used in ...
stands for aneutrino. Before the reaction there are two hydrogen nuclei (that is, two protons). Afterward there are one proton and one neutron (bound together as the nucleus of deuterium) plus a positron and a neutrino (produced as aconsequenceof the conversion of one proton to a neutron)...