Description
The present presentation reports on the status of the analysis
of the E672 experiment that was performed in July 2015 at GANIL.
The aim of the experiment was to measure lifetimes of excited states
in the 208Pb region, focusing mainly on the lifetime of the 2+ states of
204-206Hg. The nuclei of interest were populated with multi-nucleon
transfer reactions. The beam-like recoils were identified with the
VAMOS++ [1] magnetic spectrometer while the gamma rays were detected
in AGATA [2]. A Plunger device was used for the lifetime determination
based on the RDDS technique.
In this experiment, we can rely only on the mass of the fragments
detected by VAMOS in order to identify the reaction products.
The x-rays of the ejectile will be used to determine their proton number.
Although at the present stage of the analysis it is not clear yet which
part of the statistics we will be able to use to reconstruct the mass of
the beam-like product, and in particular 206Hg, the analysis showed
promising possibility for the lifetime determination of the 19/2- state
of 207Pb, located above the 13/2+ isomeric state. This 19/2- state is
expected to be a two-phonon octupole excitation build on top of a
neutron-hole excitation of 207Pb. The lifetime measurement of this
should allow to confirm, or refute, such a hypothesis. The analysis
and the preliminary results concerning this lifetime will be presented
in this contribution.
[1] M. Rejmund et al., NIM A646 (2005) 184-191
[2] S. Akkoyun et al., NIM A668 (2012) 26-58
Primary author
Dr
Damian Ralet
(CSNSM)
Co-author
Dr
Georgi Georgiev
(CSNSM)
