Erratum: Neutron phase spin echo [Phys. Rev. C93, 045501 (2016)]

Abstract

This Erratum is meant to clarify the conclusions of the original article by providing more details concerning the static magnetic field configuration applied in the neutron phase spin echo method. The measurements and results presented in the article are not affected. However, to be able to measure changes of the kinetic energy with the given resolution, the magnetic field of the apparatus has to be adapted. The technique has been described with a homogeneous magnetic field B 0 applied along the z axis in which the three spin-flip coils are positioned. This matches the actual configuration of the employed experimental setup. Using such a field allows for observing phase shifts induced by magnetic or pseudomagnetic interactions of the neutron spin. This was demonstrated using an auxiliary coil positioned in one of the spectrometer arms; compare with Fig. 4(b) of the original article. The situation corresponds also to most of the stated fundamental neutron physics applications, e.g., the search for an electric dipole moment of the neutron, exotic interactions, parity-violating spin rotations, etc. For experiments intended to measure a change in the kinetic energy, a different magnetic field configuration is required. In this case a phase shift is only obtained if the magnetic field B 0 is applied at the positions of the spin-flip coils, whereas the field between them is reduced to a value close to zero. This is the identical configuration as in the cited Ref.[1] and as briefly mentioned in the first footnote of the original article. As a consequence, the attainable energy resolution E obtained from the measured phase stability (compare with Fig. 3) has to be interpreted as a projected sensitivity. The associated field settings for the two cases are presented in the additional figure (Fig. 5, not shown in the original article).The authors would like to acknowledge important discussions with O. Zimmer. FIG. 5. (a) Scheme of the neutron phase spin echo setup with the three spin-flip coils separated by a distance L and the neutron beam in the x direction. (b) Static magnetic field configuration with a homogeneous field B 0 along the z axis to measure magnetic and pseudomagnetic effects acting on the neutron spin. This setting was applied in the presented experimental apparatus. (c) Dedicated field configuration to measure inelastic effects, i.e., changes in the kinetic energy.[1] R. Gähler and R. Golub, Z. Phys. B 65, 269 (1987).

r-process nucleosynthesis: connecting rare-isotope beam facilities with the cosmos

“…The situation is similar for (α,n) reactions [468]. In this case, however, the most important source of uncertainty is the α-nucleus optical potential [468,488]. Figure 12 compares the TALYS-calculated reaction rates of 86 Se(α, 1n) 89 Kr at temperatures between 1 GK and 10 GK using different optical-potential models.…”

“…The situation is similar for (α,n) reactions [468]. In this case, however, the most important source of uncertainty is the α-nucleus optical potential [468,488].…”

“…TALYS [458] and NON-SMOKER [459]. Recent studies have shown that the theoretical uncertainty of calculated rates for these reactions can reach factors up to 10 in the range of temperatures relevant for the α process [468] (see Sec. 7.1.5).…”

“…Besides αnucleus optical potentials, there are technical aspects intrinsic to the reaction codes that can introduce additional uncertainties. For instance, while TALYS can calculate the exclusive reaction channels (α, ×n), which must be explicitly included in network calculations, the NON-SMOKER rates are inclusive [468]. Another important aspect that needs to be investigated is the role played by reaction mechanisms that go beyond TALYS rates for the reaction 86 Se(α, 1n) 89 Kr calculated using the alpha optical-potentials from the TALYS global model (red solid line), the McFadden and Satchler model (MS), and three versions of the Demetriou-Grama-Goriely model (DGG1, DGG2, DGG3).…”

The pulsed neutron beam EDM experiment

“…This so-called phase-scan has the advantage that one performs all measurements at the resonance frequency, i.e. ω = ω 0 [21]. An additional spin-dependent interaction applied for the time T between the two π/2-pulses induces a corresponding phase-shift ∆ϕ = ∆ωT of the oscillation pattern.…”