Nuclear-resonant electron scattering

Abstract

We investigate nuclear-resonant electron scattering as occurring in the two-step process of nuclear excitation by electron capture (NEEC) followed by internal conversion. The nuclear excitation and decay are treated by a phenomenological collective model in which nuclear states and transition probabilities are described by experimental parameters. We present capture rates and resonant strengths for a number of heavy ion collision systems considering various scenarios for the resonant electron scattering process. The results show that for certain cases resonant electron scattering can have significantly larger resonance strengths than NEEC followed by the radiative decay of the nucleus. We discuss the impact of our findings on the possible experimental observation of NEEC.

Reverse conversion in 161Dy ions as an extension of dielectronic recombination

“…The cross section of RC on the K shell turns out to be roughly 4 times higher, due to the 1/p 2 factor in (11). This cross section agrees with the calculations per formed in [9][10][11][12] for neighboring nuclei. The widths of the 2p → 2s and 2p → 1s atomic transitions for the L 2 and L 3 shells are also listed in Table 3.…”

“…In an actual experi ment, this advantage can offset the general reduction in cross section with respect to the level at 43 keV. It is also worth noting that RC is, in accordance with the results presented in [9][10][11][12], more likely on the K shell in transitions with energies of ~100 keV. Therefore, experimental observation of RC could well depend on detecting the gamma quanta produced in the deexci tation of a nucleus.…”

“…We therefore must identify the specific features of this process that can serve as its unique fingerprint in order to detect reverse conversion against the back ground of radiative recombination and DR. The authors of [9][10][11][12] proposed using the NEECX process as such a facsimile. This process is a combination of RC (NEEC) and the accompanying characteristic X ray emissions.…”

“…The corresponding number of excited nuclei produced via photoabsorption is deter mined using the expression (10) where σ γ is the photoabsorption cross section. If we equate (6) to (9) and use the relation pdp = we obtain the following expression for the RC cross section: (11) Equating (8) to (10), we obtain the familiar ratio between the width of radiative decay and the cross sec tion of photoabsorption by a nucleus [5,20]: (12) Another quantity that, along with cross section (11), is useful in practice is the integral resonance strength [9,10],…”

“…The authors of [8] calculated the excitation cross section of a 76 eV isomer of the 235 U nucleus. This process was studied in detail theo retically in [9][10][11][12].…”