DSA lifetime measurements in21Ne at high recoil velocity

Abstract

States in 21Ne up to 5 MeV excitation energy have been populated using the inverted reaction 2H(2~ PT). The Doppler shift attenuation (DSA) analysis of the P7 coincidence spectra taken in a Ge(Li) detector at 45 ~ and 135 ~ and an annular silicon surface barrier detector near 0 ~ yielded the lifetimes of 8 states in 2~Ne. Due to the large recoil of vl/c~-4%o three new lifetimes were determined for the short lived levels at 2.80, 4.68 and 4.73 MeV, namely 10+4 fs, 16_+4 fs and 10_+4 fs, respectively. The results are compared with rotational and shell model calculations.

Octupole-deformed molecular bands in 21Ne

“…[15,16], ref. [13] (though not the 4679 keV I π = 3 2 + level) and Grawe et al [17] (apart from the 6271 keV level), using the 2 H( 20 Ne, p γ) reaction. One other in-band transition has previously been reported between the 3 2 + and 1 2 + levels [18], but this was not confirmed by Andritsopoulos et al [14].…”

Large Parity Admixture inNe21?

“…The ratio was found to be completely negligible, and the reduced matrix element (g.s.||Ml||2.80> can therefore be extracted from experiment. 3 Unfortunately, the mixing ratio 6 and <g.s.||£l||2.79> cannot both be extracted from the existing data, and the hindrance of the El matrix element is so large that it cannot be reliably calculated. By assuming 6 = 0 (i.e., no M2 transition) and taking the El matrix element from the lifetime of the \" state, we find…”

“…Therefore this reaction is suitable to search for the importance of an i so spin-dependent term in the two-body interaction potential in direct reactions. 3 There is also a possibility of determining the importance of noncentral terms or exchange effects in distorted-wave Born-approximation…”