positronn.

1933 Los Angeles Times 21 Feb. a2/1 A new fundamental particle of matter, the positron, discovered by a young California Institute of Technology physicist [sc. Carl D. Anderson], promises to supply an important missing link in the theory of material creation.

1933 C. D. Anderson in Science 5 May 432/2 Experiments have been carried out which gave conclusive evidence that positrons are ejected from lead by the γ-radiation of ThC″. [Note] The contraction positron is here used to denote the free positive electron.

1933 Times 9 Dec. 9/3 The unit of heavy hydrogen, the deuteron, or deuton, as it has been called, bids fair to rival in interest its recently found cousins, the neutron and positron.

1946 Ann. Reg. 1945 356 The Bethe carbon cycle (in which carbon acts as a catalyst for the conversion of hydrogen into helium and positrons).

1958 Spectator 13 June 778/3 When the electron and the positron meet they annihilate each other.

1968 C. G. Kuper Introd. Theory Superconductivity xii. 193 The conduction electrons and holes of semiconductor theory are closely analogous to the electrons and positrons of the Dirac theory.

1974 G. Reece tr. F. Hund Hist. Quantum Theory xv. 203 Not until the experimental observation of the positron..was the Dirac ‘hole’ theory generally believed.

1996 Daily Tel. 4 Jan. 4/8 Working at the CERN atom smasher in Geneva, the team managed to construct antihydrogen from the anti-matter equivalent of a proton and an electron—an antiproton and a positron.

1976 Jrnl. Nucl. Med. 17 546/1 (heading) Evaluation of positron emission tomography for study of cerebral hemodynamics in a cross section of the head using positron emitting gallium 68-EDTA and Krypton-77.

1992 Economist 26 Dec. 116/2 Positron emission tomography (PET) enables researchers to watch people think.

2002 F. Close et al. Particle Odyssey xii. 224 (caption) Coloured scans produced by Positron Emission Tomography (PET) show the brain of a person who has suffered a stroke.