Speaker
Description
The first direct high-precision measurement of the magnetic moment of the bare $^{3}$He$^{2+}$ nucleus requires resolving minuscule spin-flip-induced axial frequency shifts of the order of $50\, \text{mHz}$, a factor of $400$ smaller than observed for $^{3}$He$^{+}$ ions [1]. This challenging measurement will be performed on a single ion confined in a Penning trap at MPIK.
Current axial frequency stability is limited, amongst others, by the stability of the state-of-the-art commercial voltage source, the UM1-14, which enables relative frequency stabilization at a level $2\cdot 10^{-8}$ [2], corresponding to several tens of $\text{mHz}$.
To overcome this limitation, we replace the UM1-14 with a $1\, \text{V}$ programmable Josephson Voltage Standard (PJVS), built at PTB Braunschweig. Based on the inverse AC Josephson effect, the PJVS generates a voltage that depends solely on the irradiation frequency of the Josephson junctions and fundamental constants which are fixed to exact values in the SI system. This eliminates dependencies on junction geometry, temperature, and other experimental conditions. This near-ideal frequency-to-voltage conversion is expected to improve axial frequency resolution by at least a factor of two.
We present progress in the integration and characterization of the PJVS, report stability measurements and outline the timeline toward achieving the first direct determination of the $^{3}$He$^{2+}$ magnetic moment.
References:
[1] Schneider et al., Nature 606, 878–883 (2022).
[2] Kaiser et al., Appl. Phys. Lett. 124, 224002 (2024).
| Academic level | PhD student |
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