Neutron resonance spectroscopy: The separated isotopes of Dy

Results are given for the neutron resonance parameters of the Dy isotopes (160 to 164) based on 202.05 m transmission and 39.536 m capture self-indication flight path time of flight measurements using the Columbia-Nevis synchrocyclotron. The A=161 to 164 samples were {~} 92 to 98% enriched. The ¹⁶⁰Dy sample was 69.5% enriched. We give E₀ and (g)Γₙ⁰ values for: ¹⁶⁰Dy---64 levels to 2 keV; ¹⁶¹Dy---251 levels to 1 keV; ¹⁶²Dy---142 levels to 16 keV; ¹⁶³Dy---114 levels to 1 keV; ¹⁶⁴Dy---116 levels to 21 keV. The 〈Γ_γ〉 values and (numbers) of Γ_γ values were 108 meV (9), 112 meV (26), 112 meV (16), 113 meV (39), and 114 meV (5), respectively. A shape fit to the strong asymmetric level at 147 eV in ¹⁶⁴Dy gave R^'=7.5 fm. The $l=0$ strength functions, 10⁴S₀, are (2.00±{}0.36), (1.73±{}0.17), (1.88±{}0.25), (2.02±{}0.30), and (1.70±{}0.25), respectively. Using our threshold sensitivities for level detection vs E, and various statistical tests, indicates the following numbers of missed s levels to the Eₘₐₓ where most s levels were seen as: ¹⁶⁰Dy---2 to 900 eV; ¹⁶¹Dy---5 to 140 eV; ¹⁶²Dy---2 to 3 keV and 6 to 4.5 keV; ¹⁶³Dy---2 to 220 eV; and ¹⁶⁴Dy---2 to 5 keV. No p levels were included for 160, 161, 163, but a few were present for 162 and 164, giving 10⁴S₁=(1.1±0.4)(¹⁶²Dy) and (1.3±0.3)(¹⁶⁴Dy). Various statistical tests suggest where the missed s levels should be located to give good agreement with the tests, giving $〈{D}₀〉=(27.3±{}1.7), (2.67±{}0.13), (64.6±{}1.9), (6.85±{}0.54), and (147±{}9)$ eV, respectively.NUCLEAR REACTIONS $160,161,162,163,164Dy$ ($n, n$), ($n, {γ}$), $E=1$ eV-few keV; measured ${{σ}}ₜ(E)$; deduced ${E}ₒ$, $g{{Γ}}ₙᵒ$, ${{Γ}}_{{γ}}$, ${S}₀$, $〈{D}₀〉$, ${S}₁$; various statistical tests.