A comparative spectroscopic investigation of21Ne and21F by pickup reactions

Abstract

The reactions 22Ne (d,t)21Ne and 22Ne(d,t)2~F have been investigated in a parallel experiment at E~=52 MeV. Energy spectra of tritons and r particles have been measured up to excitation energies of 18 MeV in both ZtNe and 2tF nuclei. The l values could be determined, and spectroscopic factors have been obtained by a DWBA analysis of the measured angular distributions. Together with the results from a preceding 22Ne(I],r)2aF experiment, several spins could be determined in 2~F. From a comparison of the triton and z particle spectra, T=3/2 states in 21Ne could be identified and on this basis the new information on spins of Z aF states could be transferred to their analog states in ZINc. The complete T< and 7-> parts of the (2s, ld) strengths could be observed. The l p strength is highly fragmented. Of the T< part only 601',i of the lp1;2 and 40~,] of the 1p3,2 strength could be found, but the total T> part of the lp strength could be localized. The spectroscopic results for positive parity states are in qualitatively good agreement with shell model predictions. E: Nuclear Reactions: 22Ne(d, t), 22Ne(d, r), E =52 MeV; measured ~-(0). 2]Ne, 21F deduced levels, I, l, ~z, 7; S. Enriched target.

Spins and parities of hole states in25Na and25Mg

“…Similar observations have been made previously [8,9] for neutron pick-up from other T= 1 target nuclei in the 2 s, I d shelk Isospin conservation provided, the information on the T= 3/2 neutron pick-up strength is redundant in principle. The resulting T =1/2 spectroscopic factors for pick-up from the 2s, l d shells then turn out close to the shell model value of 4.67, but only ~40~ of the expected T = 1/2 l p neutron hole strength (t2 C 2 S=4) could be located.…”

“…Among others the parent-analog relations are based on intensity arguments. This is a well-known problem observed in the (d, t) reaction on several T= 1 target nuclei [5,9] which apparently results from an underestimate of the cross section by the standard DWBA procedure. Obviously the values in Table 4 are too large in the case of neutron pick-up.…”

“…Therefore it suggested itself to measure vector analyzing powers for the 26Mg(d~ r)ZSNa reaction to obtain the missing information. As for the pick-up reaction on 180 and 22Ne [8,9] a parallel measurement of the (d, ~) and (d, t) reactions (with unpolarized deuterons) on 26Mg constitutes a simple experimental method to unambiguously identify the T=3/2 analog states in 25Mg. In ZSMg the situation is quite different.…”

Experimental study of the effective nucleon-nucleon interaction using the F21(d,p)F22

“…In terms of the proton shell closure, there is a large amount of data supporting a robust proton π0p 1/2 -π1s 1/2 Z = 8 shell gap in the neutron-rich oxygen isotopes [30,31]. In addition, data from the 22 Ne(d, 3 He) 21 F reaction showed that the 21 F 5/2 + ground state carried > 70% of the proton 0d 5/2 strength [33], which is consistent with a closed Z = 8 proton shell and restricts the valance proton to the π0d 5/2 orbital in 22 F for states populated strongly in the 21…”