$g$ factor of the first excited state in ${}^{56}\mathrm{Fe}$ and implications for transient-field calibration in the Fe region

The transient-field technique has been used to measure the $g$ factor of the $2_1^{+}$ state in ${}^{56}\mathrm{Fe}$ relative to the independently determined $g$ factor of the first $5/2^{-}$ state in ${}^{57}\mathrm{Fe}$. The new result for ${}^{56}\mathrm{Fe}$ agrees with previous measurements but is more precise. Implications for calibrating the transient field and $g$-factor measurements in the $\mathit{fp}$ region are discussed.

Figure 1

Schematic view of the arrangement of the particle detectors. The dimensions of the active area are indicated on the lower detector.

Figure 2

Spectrum of ${}^{57}\mathrm{Fe}\hspace{0.5em}\gamma$ rays observed at $+{65}^{°}$ to the beam axis in coincidence with the central particle detector. This spectrum represents about 16 h of data for the field-up direction, obtained during the precession measurement.

Figure 3

Measured and calculated (unperturbed) angular correlations for ${}^{56}\mathrm{Fe}$ in inverse kinematics. The upper panel is for the center particle detector, the lower panel is for the top and bottom (outer) detectors. The range of particle detection angles in the vertical plane, above and below the beam axis, is indicated.

Figure 4

Similar to Fig. 3, but showing the measured and calculated angular correlations for the $5/2_1^{-}\to 1/2_1^{-}$ 136 keV (left panels) and $5/2_1^{-}\to 3/2_1^{-}$ 122 keV (right panels) transitions in ${}^{57}\mathrm{Fe}$.