Scissors Mode of¹⁶²Dy Studied from Resonance Neutron Capture

Abstract

Abstract. Multi-step cascade γ-ray spectra from the neutron capture at isolated resonances of 161 Dy nucleus were measured at the LANSCE/DANCE time-of-flight facility in Los Alamos National Laboratory. The objectives of this experiment were to confirm and possibly extend the spin assignment of s-wave neutron resonances and get new information on photon strength functions with emphasis on the role of the M1 scissors mode vibration. The preliminary results show that the scissors mode plays a significant role in all transitions between accessible states of the studied nucleus. The photon strength functions describing well our data are compared to results from 3 He-induced reactions, (n,γ) experiments on Gd isotopes, and (γ,γ') reactions.

Statistical properties of the well deformed Sm153,155 nuclei and the scissors resonance

“…Since then, many heavy deformed even-even and odd-mass rare-earth nuclei have been systematically investigated. So far, the SR mode has been experimentally observed in vibrational and rotational [8], as well as in γ -soft nuclei [9,10] and has also been observed in the actinide region [11][12][13][14][15][16][17], as well as in the rare-earth mass region [4,[18][19][20][21][22][23][24][25][26][27].…”

“…A range of different experimental techniques have been used to investigate the low-energy SR. These include ground state absorption experiments such as inelastic electron scattering [6], nuclear resonance fluorescence (NRF) [28], and average resonance capture (ARC) [29], as well as γ -decay experiments such as radiative neutron capture [22,25] and the Oslo method [30,31], which extracts information from ion scattering or transfer reactions. In general, γ -decay experiments have yielded larger SR strengths than the ground state absorption experiments.…”

“…It is suggested that the splitting of the SR may be due to the isovector spin-scissors mode [35], or due to triaxiality [36]. The splitting in the SR has not been reported for any of the rare-earth nuclei studied with the NRF technique [37], with the Oslo method [18][19][20][21]23,24,26,27], or other techniques [4,22,25].…”

Nuclear level densities and γ -ray strength functions of Ta180,181,182

“…[20] and references therein), the SR has also been observed in less-deformed nuclei, e.g., in vibrational even-mass 122−130 Te [21], transitional 190,192 Os [22], and in γ -soft 134 Ba and 196 Pt [23,24] nuclei. The SR has been investigated through nuclear resonance fluorescence (NRF) [25], resonance neutron capture [26], and through the Oslo method in the rare-earth [27] and actinide [28][29][30][31] regions.…”

Nuclear level densities and gamma-ray strength functions of $^{180,181,182}$Ta

“…in vibrational even-mass 122−130 Te [21], transitional 190,192 Os [22], and in γ-soft 134 Ba and 196 Pt [23,24] nuclei. The SR has been investigated through nuclear resonance fluorescence (NRF) [25], resonance neutron capture [26], and through the Oslo Method in the rare-earth [27] and actinide [28][29][30][31] regions. A re-view of the theoretical and experimental findings can be found in Ref.…”