Jun 13 – 17, 2022
Berkeley, CA
US/Pacific timezone

Direct Population and Lifetime Measurement of the $2^+_1$ State in $^{40}$Ca via an Alpha-transfer Reaction

Not scheduled
Berkeley, CA

Berkeley, CA

Lawrence Berkeley National Laboratory
Oral Poster Presentations Poster Session


Frank (Tongan) Wu (Simon Fraser University)


At TRIUMF, Canada’s particle accelerator centre, the TIGRESS Integrated Plunger (TIP) and its configurable detector systems have been used for charged-particle tagging and light-ion identification in Doppler-shift lifetime measurements using gamma-ray spectroscopy with the TIGRESS array of HPGe detectors. An experiment using these devices to measure the lifetime of the $2^+_1$ state of $^{40}$Ca has been performed by projecting an $^{36}$Ar beam onto a $^\text{nat.}$C target. Analysis of the experimental gamma-ray spectra confirmed the direct population of the $2^+_1$ state. Kinematics of the reaction mechanism was identified using Monte-Carlo simulations, which also enabled the use of charged-particle correlations to select reactions that populated a specific excited state in the $^{40}$Ca immediately after its production. Selection of the $2^+_1$ state with this additional sensitivity further eliminated feeding cascades, and therefore restricted the decay kinetics predominantly to first order. The current work is on expanding the simulation to incorporate the stopping of the $^{40}$Ca and enabling the emission of gamma rays to provide a Doppler Shift Attenuation Method measurement of the lifetime of the $2^+_1$ state in $^{40}$Ca. Results of analysis of the experimental data and simulations will be presented and discussed.

Primary authors

Frank (Tongan) Wu (Simon Fraser University) Prof. Krzysztof Starosta (Simon Fraser University) Prof. Greg Hackman (TRIUMF) Dr Phil Voss (Simon Fraser University) Dr Jonathan Williams (TRIUMF) Dr Aaron Chester (NSCL) Prof. Corina Andreoiu (Simon Fraser University) Dr Gordon Ball (TRIUMF) David Cross Dr T. E. Drake (University of Toronto) Prof. Adam Garnsworthy (TRIUMF) Dr Jennifer Pore (Lawrence Berkeley National Laboratory) Prof. Carl Svensson (University of Guelph) Dr Carl David Unsworth (University of Liverpool)

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