Summary
The mean lives of some low-lying levels in47Sc have been measured using the Doppler-shift attenuation method with p-γ coincidences in the44Ca(α, pγ)47Sc reaction. The following values have been obtained: >8 ps, (4.5±1.6) ps, (90±35) fs, >6 ps, (1.4±0.4) ps, (300±80) fs, (440±80) fs, <70 fs, (570±120) fs, (120±60) fs, (450±170) fs for the levels at 808, 1147, 1297, 1391, 1404, 1798, 1857, 1878, 2002, 2207, 2410 keV, respectively. Branchings of levels were also assigned. The present measurement allows us to propose a nearly complete level scheme for low-lying states in47Sc.M1 transitions are rather fast (of order of 0.1 W.u.) and alsoE1 transitions are not very hindered (of order of few 10−4 W.u.).
Riassunto
Sono state misurate le vite medie di alcuni dei livelli di bassa energia nello47Sc, usando la tecnica dell’attenuazione dell’effetto Doppler. I rggi gamma sono stati osservati in coincidenza con i protoni nella reazione44Ca(α, pγ)47Sc. Sono stati ottenuti i seguenti valori: >8 ps, (4.5±1.6) ps, (90±35) fs, >6 ps, (1.4±0.4) ps, (300±80) fs, (440±80) fs, <70 fs, (570±120) fs, (120±60) fs, (450±170) fs per i livelli a 808, 1147, 1297, 1391, 1798, 1857, 1878, 2002, 2007, 2410 keV, rispettivamente. Sono inoltre stati assegnati i branchings dei livelli. I presenti risultati permettono di proporre uno schema di livelli abbastanza completo. Le transizioniM1 sono risultate essere piuttosto rapide (dell’ordine di 0.1 W.u.) ed anche le transizioniE1 non sono molto ritardate (dall’ordine di alcuni 10−4 W.u.).
Реэюме
Были иэмерены средние времена жиэни некоторых ниэколежашие уровней в47Sc, испольэуя метод ослабления допплеровского сдвига с p-γ совпадениями в реакции44Ca(α, pγ)47Sc. Получены следуюшие эначения: >8 ps, (4.5±1.6) ps, (90±35) fs, >6 ps, (1.4±0.4) ps, (300±80) fs, (440±80) fs, <70 fs, (570±120) fs, (120±60) fs, (450±170) fs соответственно для уровней при 808, 1147, 1297, 1391, 1404, 1798, 1857, 1878, 2002, 2207, 2410 кзВ. Также были приписаны ветвления уровней. Настояшие иэмерения поэволяют предположить почти полную схему уровней для ниэколежаших состояний в47Sc. ПереходыM1 являются довольно быстрыми σпорядка 0.1 W.u)., переходыE1 также являются не очень эатрудненными σпорядка нескольких 10−4 W.u.).
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Another possibility is that the reaction proceeds through a two-step process as it has been suggested in heavy ions particle transfer and also in the48T(d, τ) reaction (4).
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Barci, V., Brandolini, F. & Morando, M. Lifetime measurements of low-lying levels in47Sc. Nuov Cim A 11, 1–12 (1972). https://doi.org/10.1007/BF02722773
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DOI: https://doi.org/10.1007/BF02722773