Proton emission (also known as proton radioactivity) is a type of radioactive decay in which a proton is ejected from a nucleus. Proton emission can occur from high-lying excited states in a nucleus following a beta decay, in which case the process is known as beta-delayed proton emission, or can occur from the ground state (or a low-lying isomer) of very proton-rich nuclei, in which case the process is very similar to alpha decay. For a proton to escape a nucleus, the proton separation energy must be negative - the proton is therefore unbound, and tunnels through the Coulomb barrier in a finite time. Proton emission is not seen in naturally-occurring isotopes; proton emitters can be produced via nuclear reactions, usually utilising some kind of particle accelerator. The R process (R for rapid) is a neutron capture process for radioactive elements which occurs in high neutron density, high temperature conditions. ... The S process (S for slow) is a neutron capture process in the decay of radioactive elements that occurs in lower neutron density, lower temperature conditions. ... The p process was believed to be a proton capture process which occurrs during supernovae explosions. ... Properties In physics, the proton (Greek proton = first) is a subatomic particle with an electric charge of one positive fundamental unit (1. ... Nucleus can mean: The Nuclear Envelope The nucleus is enveloped by a pair of membranes enclosing a lumen that is continuous with that of the endoplasmic reticulum. ... In nuclear physics, beta decay (sometimes called neutron decay) is a type of radioactive decay in which a beta particle (an electron or a positron) is emitted. ... A nuclear isomer is a metastable or isomeric state of an atom caused by the excitation of a proton or neutron in its nucleus so that it requires a change in spin before it can release its extra energy. ... Alpha decay is a form of radioactive decay in which an atomic nucleus ejects an alpha particle and transforms into a nucleus with mass number 4 less and atomic number 2 less. ... Quantum tunneling is the quantum-mechanical effect of transitioning through a classically-forbidden energy state. ... It has been suggested that this article or section be merged into Electrostatic force. ... In nuclear physics, a nuclear reaction is a process in which two nuclei or nuclear particles collide, to produce products different to the initial products. ... A 1960s single stage 2MeV linear Van de Graaff accelerator, here opened for maintenance A particle accelerator is a device which uses electric and/or magnetic fields to propel electrically charged particles to high speeds. ...

Although prompt (i.e. not beta-delayed) proton emission was observed from an isomer in Cobalt-53 as early as 1969, no other proton-emitting states were found until 1981, when the proton radioactive ground states of Lutetium-151 and Thulium-147 were observed at experiments at GSI. Research in the field flourished after this breakthrough, and to date more than 25 isotopes have been found to exhibit proton emission. The study of proton emission has aided the understanding of nuclear deformation, masses and structure, and is a wonderfully pure example of quantum tunneling. General Name, Symbol, Number cobalt, Co, 27 Chemical series transition metals Group, Period, Block 9, 4, d Appearance metallic with gray tinge Atomic mass 58. ... 1969 (MCMLXIX) was a common year starting on Wednesday For other uses, see Number 1969. ... 1981 (MCMLXXXI) is a common year starting on Thursday of the Gregorian calendar. ... General Name, Symbol, Number lutetium, Lu, 71 Chemical series lanthanides Group, Period, Block ?, 6, d Appearance silvery white Atomic mass 174. ... General Name, Symbol, Number thulium, Tm, 69 Chemical series lanthanides Group, Period, Block ?, 6, f Appearance silvery gray Atomic mass 168. ... The Gesellschaft für Schwerionenforschung mbH (GSI, Institute for Heavy Ion Research) in Wixhausen, a suburb of Darmstadt, Germany is a federally funded heavy ion research center. ... Quantum tunneling is the quantum-mechanical effect of transitioning through a classically-forbidden energy state. ...

In 2002, the simultaneous emission of two protons was observed from the nucleus Iron-45 in experiments at GSI and GANIL (Grand Accelerateur National d'Ions Lourds, near Caen). In 2005 it was experimentally determined (at the same facility) that Zinc-54 can also undergo double proton decay. 2002 (MMII) is a common year starting on Tuesday of the Gregorian calendar. ... General Name, Symbol, Number iron, Fe, 26 Chemical series transition metals Group, Period, Block 8, 4, d Appearance lustrous metallic with a grayish tinge Atomic mass 55. ... The Gesellschaft für Schwerionenforschung mbH (GSI, Institute for Heavy Ion Research) in Wixhausen, a suburb of Darmstadt, Germany is a federally funded heavy ion research center. ... Location within France Caen is a city and a commune of northwestern France. ... General Name, Symbol, Number zinc, Zn, 30 Chemical series transition metals Group, Period, Block 12, 4, d Appearance bluish pale gray Atomic mass 65. ...

See also

• Free neutron