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The .22Ne(α,.n) and .22Ne(α,.γ) reactions are pivotal in neutron production for the s-process, which creates elements heavier than iron. This study analyzes the competition between these reactions, focusing on the α-particle and neutron thresholds, with critical energy levels often possessing uncertain quantum numbers. Previous experiments have explored related transfer, photoexcitation, and neutron capture processes. We aim to carry out direct reactions of .22Ne to enhance our understanding of neutron sources, requiring stable accelerator conditions around 820 keV.
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22Ne(α, γ/n) • 22Ne(α, n)25Mg reaction is the main source of neutrons for s-process • - there is competition from the 22Ne(α, γ)26Mg reaction • - s-process is the origin of nuclides heavier than iron • The α-particle and neutron threshold are: Sα = 10.615 MeV andSn= 11.093 MeV • - many of the states in this energy range (and a little higher energy) have uncertain energies and quantum number, which are important ingredients for rate calculations • According to Endtet al., there are 21 levels between Sα and Snthresholds, most of which have unknown energies and quantum numbers • α and 22Ne have spin and parity of 0+, hence they tend to populate natural parity states: • 0+, 1-, 2+, 3-, 4+, …
22Ne(α, γ/n) • Some previous experiments include: • α- particle transfer: 22Ne(6Li,d)26Mg by CladioUgaldeet al. • photoexcitation: 26Mg(γ, γ’) 26Mg by Longlandet al. • neutron capture: 25Mg(n, γ) 26Mg by Koehler • We intend to conduct the direct reaction of • 22Ne(α,n)25Mg and 22Ne(α,γ)26Mg • 22Ne(α,x) has Coulomb barrier of 0.229 MeV • To conduct this experiment, we need the accelerator to be stable at ~ 820 keV • - this is about 11.3 MeV excitation energy
