Relatore
Sig.
Adam Nichols
(University of York)
Descrizione
There has been intense physics interest in the structure of self-conjugate medium mass nuclei in recent years [1-3]. Specific effort has been undertaken to map out the development of collectivity above mass 60, with emphasis on the influence of the deformation-driving g9/2 orbital. A number of even-even nuclei in this area have been studied, with B(E2) values deduced for 64Ge, 68Se, 72Kr and 76Sr (see ref. [4] and references therein). However no published measurements exist for the intervening odd-odd N=Z nuclei. An experiment was thus conducted to continue the mapping of deformation in the A=70 region by measuring the lifetime of the first excited 2+ state in the odd-odd N=Z nucleus 70Br.
Excited states in 70Br were populated via one-nucleon-knockout at the NSCL facility at Michigan State University. De-excitation gamma rays were detected using the SeGA array, recorded in coincidence with recoils identified in the S800 spectrograph. The lifetime was deduced using the recoil distance Doppler shift technique, made possible through the use of a new differential plunger apparatus (TRIPLEX). The lifetime of the 2+ state in neighbouring 70Se was also measured for comparison, due to recent controversy over the shapes of the two nuclei. Lifetimes of low-lying states in 70Br, 70Se and other neighbouring nuclei will be presented and discussed.
[1] A. Petrovici, J. Phys. G Nucl. Part. Phys., 37 064036 (2010)
[2] K. Kanecko et al., Phys. Rev. Lett., 109 092504 (2012)
[3] M. Hasegawa et al., Phys. Lett. B, 656 51-55 (2007)
[4] A. Lemasson et al., Phys. Rev. C, 85 041303(R) (2012)
Autore principale
Sig.
Adam Nichols
(University of York)
Coautore
Dr.
Alexandra Gade
(NSCL, Michigan State University)
Alfred Dewald
(Institut für Kernphysik, Universität zu Köln)
Dr.
Antoine Lemasson
(GANIL, Caen)
Dr.
Christoph Fransen
(IKP Koeln)
Dr.
Daniel Bazin
(NSCL, Michigan)
Dr.
David Jenkins
(University of York)
Dr.
David Miller
(University of Tennessee)
Dr.
Dirk Weisshar
(NSCL, Michigan)
Giacomo De Angelis
(INFN Legnaro)
Prof.
Hironori Iwasaki
(NSCL, Michigan State University)
Sig.
Jack Henderson
(University of York)
Dr.
Jill Berryman
(NSCL, Michigan State University)
Dr.
Kathin Wimmer
(NSCL, Michigan State University)
Sig.
Matthias Hackstein
(Institut für Kernphysik, Universität zu Köln)
Prof.
Mike Bentley
(University of York)
Dr.
Nara Singh Bondili
(University of York)
Dr.
Paul Davies
(University of York)
Prof.
Robert Wadsworth
(University of York)
Sig.
Thomas Braunroth
(IKP Koeln)
