Peter John Twin (born 26 July 1939 inLondon)[1] is a British experimental nuclear physicist. He is known for his research into the structure of atomic nuclei, based upon his pioneering work on techniques ofgamma ray spectroscopy and, specifically, the Total Energy Suppression Shield Array (TESSA).[2][3]
Peter J. Twin graduated from theUniversity of Liverpool with a B.Sc. in 1960 and a Ph.D. in 1964. At theUniversity of Liverpool he became a lecturer in 1964, a Senior Lecturer in 1973, a Reader in 1979,[2] Sir James Chadwick Professor of Experimental Physics in 1987, Lyon James Professor of Physics in 1997,[4] and a Senior Fellow and Professor Emeritus in 2001. From 1983 to 1987 he was also Head of the Nuclear Structure Facility at the Daresbury Laboratory, which is about 30 kilometres from Liverpool. For the academic year 1968–1969 he was a visiting professor at theUniversity of Alberta.[2]
In 1986 his science team discoveredsuperdeformed nuclei with a highspin (with an observation of ayrast line in thegamma spectrum).[5] In 1991Daniel Kleppner judged Twin's discovery of superdeformed nuclei to be one most important discoveries in physics in the years from 1986 to 1991.[6] In retrospect, the phenomenon was also observed in 1962 whenspontaneous fission ofisomers in heavy nuclei was discovered by Sergey Polikanov (1926–1994).
Following the success of TESSA III, he collaborated with Francis Beck, director of theCentre de recherches nucléaires (CRN) atStrasbourg, on leading the French-British development of the more advanced gamma ray detectors of the Eurogam project. Eurogam I became operational in 1992 at Daresbury, and Eurogam II became operational in 1994 at Strasbourg.[2][8] The detector arrays of Eurogam culminated in the EUROBALL detector array (which became operational in 1996).[2][9]
Twin, P. J.; Nolan, P. J.; Aryaeinejad, R.; Love, D. J. G.; Nelson, A. H.; Kirwan, A. (1983). "TESSA: A multi-detector γ-ray array designed to study high spin states".Nuclear Physics A.409:343–351.Bibcode:1983NuPhA.409..343T.doi:10.1016/0375-9474(83)90696-6.
Twin, P. J.; Nyakó, B. M.; Nelson, A. H.; Simpson, J.; Bentley, M. A.; Cranmer-Gordon, H. W.; Forsyth, P. D.; Howe, D.; Mokhtar, A. R.; Morrison, J. D.; Sharpey-Schafer, J. F.; Sletten, G. (1986). "Observation of a Discrete-Line Superdeformed Band up to 60ℏ in152Dy".Physical Review Letters.57 (7):811–814.Bibcode:1986PhRvL..57..811T.doi:10.1103/PhysRevLett.57.811.PMID10034167.
Byrski, T.; Beck, F. A.; Curien, D.; Schuck, C.; Fallon, P.; Alderson, A.; Ali, I.; Bentley, M. A.; Bruce, A. M.; Forsyth, P. D.; Howe, D.; Roberts, J. W.; Sharpey-Schafer, J. F.; Smith, G.; Twin, P. J. (1990). "Observation of identical superdeformed bands in N=86 nuclei".Physical Review Letters.64 (14):1650–1653.Bibcode:1990PhRvL..64.1650B.doi:10.1103/PhysRevLett.64.1650.PMID10041452.
Nazarewicz, W.; Twin, P. J.; Fallon, P.; Garrett, J. D. (1990). "Natural-parity states in superdeformed bands and pseudo SU(3) symmetry at extreme conditions".Physical Review Letters.64 (14):1654–1657.Bibcode:1990PhRvL..64.1654N.doi:10.1103/PhysRevLett.64.1654.PMID10041453.
Beausang, C.W.; Forbes, S.A.; Fallon, P.; Nolan, P.J.; Twin, P.J.; Mo, J.N.; Lisle, J.C.; Bentley, M.A.; Simpson, J.; Beck, F.A.; Curien, D.; Defrance, G.; Duchêne, G.; Popescu, D. (1992). "Measurements on prototype Ge and BGO detectors for the Eurogam array".Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.313 (1–2):37–49.Bibcode:1992NIMPA.313...37B.doi:10.1016/0168-9002(92)90084-H.
Flibotte, S.; et al. (1993). "ΔI=4 bifurcation in a superdeformed band: Evidence for aC4 symmetry".Physical Review Letters.71 (26):4299–4302.Bibcode:1993PhRvL..71.4299F.doi:10.1103/PhysRevLett.71.4299.PMID10055211. (Flibotte collaborated with 29 co-authors, among whom is P. J. Twin.)
Duchêne, G.; Beck, F.A.; Twin, P.J.; De France, G.; Curien, D.; Han, L.; Beausang, C.W.; Bentley, M.A.; Nolan, P.J.; Simpson, J. (1999). "The Clover: A new generation of composite Ge detectors".Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment.432 (1):90–110.Bibcode:1999NIMPA.432...90D.doi:10.1016/S0168-9002(99)00277-6. (over 450 citations)
^The original TESSA used 6 germanium detectors with NaI crystals in the suppression shields. Both TESSA2 and TESSA3 replaced the NaI crystals with bismuth germanate. TESSA 2 had 6 germanium detectors, but TESSA 3 was upgraded to 16 germanium detectors.
^Twin, P.J.; Nyakó, B.M.; Nelson, A.H.; Simpson, J.; Bentley, M.A.; Cranmer-Gordon, H.W.; Forsyth, P.D.; Howe, D.; Mokhtar, A.R.; Morrison, J.D.; Sharpey-Schafer, J.F. (1986). "Observation of a Discrete-Line Superdeformed Band up to 60 ℏ in152Dy".Physical Review Letters.57 (7):811–814.Bibcode:1986PhRvL..57..811T.doi:10.1103/PhysRevLett.57.811.PMID10034167. (over 900 citations)
^Kleppner, Daniel (December 1991), "A Lesson in Humility",Physics Today (in German), vol. 44, no. 12, p. 9,Bibcode:1991PhT....44l...9K,doi:10.1063/1.2810343 Kleppner's article criticizes the National Research Council's 1986 preview of physics (Brinkman Report, chaired byWilliam F. Brinkman).Schewe, Phillip F.; Stein, Ben (December 27, 1991)."Physics News Update".American Institute of Physics Bulletin (# 60). Archived fromthe original on 2004-09-06.