Angular Distribution Measurements of Gamma-rays from Unbound T = 1 States in ²²Na

Abstract

Angular distributions have been measured at six 21Ne(p, γ)22Na analogue resonances, with Ep = 0.70, 0.77, 1.09, 1.21, 1.56 and 1.84 MeV, and at a candidate for analogue resonance with Ep = 1.11 MeV. Gamma-ray mixing ratios have been obtained for the first time for the decays of these levels with determination of spin-parity assignments. The spins and parities for the bound states at 1.98 and 4.36 MeV have been deduced. Transition strengths provide information on the isoscalar and isovector strengths in the self-conjugated nucleus 22Na.

Production and characterization of oxygen-reduced implanted 21Ne targets

“…This has the advantage that only summing-in corrections apply and they are negligible in both cases (<1%). In addition the known angular distributions [12,14] are consistent with isotropy. The cyield was measured with a HPGe detector at 0°, whose efficiency has been calibrated using the 27 Al(p, c) resonances at 406 and 992 keV [15][16][17][18][19].…”

“…The 21 Ne implanted targets were characterized using the 21 [12,14]. This has the advantage that only summing-in corrections apply and they are negligible in both cases (<1%).…”

“…Since the target-detector distance was only about 2.5 cm, summing corrections [20] in the order of 10% had to be applied to cascade transitions in the efficiency measurement. In addition the data were also corrected for angular distribution effects within a couple of percent [21,22,14]. For the single resonance, which has the small resonance width compared to the energy loss of ions in the target, the yield is described as the ''thick target yield" [23].…”