Microcanonical entropies and radiative strength functions ofV50,51

Abstract

The level densities and radiative strength functions (RSFs) of 50,51 V have been extracted using the ( 3 He,αγ) and ( 3 He, 3 He ′ γ) reactions, respectively. From the level densities, microcanonical entropies are deduced. The high γ-energy part of the measured RSF fits well with the tail of the giant electric dipole resonance. A significant enhancement over the predicted strength in the region of Eγ < ∼ 3 MeV is seen, which at present has no theoretical explanation.

Statistical γ -decay properties of Ni64 and deduced ( n,γ ) cross section of the Campo1, Garrote2, Eriksen3 et al. 2016Phys. Rev. CSelf Cite

“…At excitation energies above E x ≈ 4.5 MeV a saturation of known energy levels is observed. Above E x ≈ 5 MeV the level density seems to be well described by the CTM [2,45], as previously seen for other nuclei such as 50,51 V [17] or 97 Mo [46]. As a final remark in this section, it must be noted that in Eq.…”

“…One of the most surprising features observed in the γ -strength function is the increased probability of γ decay with γ energies below 2-4 MeV, first seen in 56,57 Fe in 2004 [11]. Since then, this low-energy enhancement or upbend has been measured for several nuclei from Sc to Sm [11][12][13][14][15][16][17][18][19] and confirmed with an independent method for 95 Mo [20]. The physical mechanisms underlying this enhancement are still not clarified.…”

Low energy magnetic radiation enhancement in thef7/2shell

“…In the last decade things have become more complicated, since measurements of the γSF [10,[14][15][16][17][18][19][20][21][22][23][24][25][26] have revealed a newly observed minimum around E γ ≃ 2 − 4 MeV, so besides the high E γ enhancement, there is also a low E γ enhancement. The first attempts to understand the low-E γ enhancement [14,15,17] used the KMF model to describe the GDR; the contribution of the giant magnetic dipole resonance to the total γSF is fitted by a Lorentzian, similarly to the E2 resonance, while the low-E γ region is described by a separate term that has a power-law parametrization.…”

Level density andγ-decay properties of closed shell Pb nuclei

“…The Oslo method has previously been applied for rare earth nuclei, obtaining information on the level density and average γ-decay properties in this mass region [6,7]. Recently, the method has been extended to other mass regions like Fe, Mo, V and Sc [8,9,10,11,12]. In order to check the validity of the method in cases where nuclei have low level density and strong Porter-Thomas fluctuations [13], the 27,28 Si nuclei were studied with gratifying results [14].…”