In: Physics Letters B, 2015, vol. 745, p. 58–63
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In: Physics Letters B, 2014, vol. 739, p. 128–132
The neutron gyromagnetic ratio has been measured relative to that of the 199Hg atom with an uncertainty of 0.8 ppm. We employed an apparatus where ultracold neutrons and mercury atoms are stored in the same volume and report the result γn/γHg=3.8424574(30)γn/γHg=3.8424574(30).
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In: Journal of Applied Physics, 2014, vol. 116, no. 8, p. 084510
The Surrounding Field Compensation (SFC) system described in this work is installed around the four-layer Mu-metal magnetic shield of the neutron electric dipole moment spectrometer located at the Paul Scherrer Institute. The SFC system reduces the DC component of the external magnetic field by a factor of about 20. Within a control volume of approximately 2.5 m × 2.5 m × 3 m,...
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In: Biomedical Engineering / Biomedizinische Technik, 2013, vol. 58, no. SI-1-Track-L, p. 000010151520134294
We present first results on the imaging of the two dimensional magnetic field distributions using a recently developed magnetic field imaging camera (MFIC). The instrument is based on laser-pumped atomic magnetometry with an alkali vapour in a buffer gas. The device provides millimetre spatial and sub-second time resolution, and allows mapping the magnetic field from circa 2 cm2...
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In: Physica B: Condensed Matter, 2011, vol. 406, no. 12, p. 2365-2369
Physics at the Planck scale could be revealed by looking for tiny violations of fundamental symmetries in low energy experiments. In 2008, a sensitive test of the isotropy of the universe has been performed with stored ultracold neutrons (UCN), this is the first clock-comparison experiment performed with free neutrons. During several days we monitored the Larmor frequency of neutron spins in a...
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In: Physical Review Letters, 2009, vol. 103, no. 8, p. 081602
A clock comparison experiment, analyzing the ratio of spin precession frequencies of stored ultracold neutrons and ¹⁹⁹Hg atoms, is reported. No daily variation of this ratio could be found, from which is set an upper limit on the Lorentz invariance violating cosmic anisotropy field b⊥<2×10⁻²⁰ eV (95% C.L.). This is the first limit for the free neutron. This result...
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In: Applied Physics B, 2009, vol. 96, no. 4, p. 763-772
We have manufactured more than 250 nominally identical paraffin-coated Cs vapor cells (28 mm inner diameter bulbs) for multi-channel atomic magnetometer applications. We describe our dedicated cell characterization apparatus. For each cell we have determined the intrinsic longitudinal, Γ ₀₁, and transverse, Γ ₀₂, relaxation rates. Our best cell shows Γ...
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In: Nuclear Instruments and Methods in Physics Research Section A, 2009, p. -
The effort towards a new measurement of the neutron electric dipole moment (nEDM) at the Paul Scherrer Institut's (PSI) new high intensity source of ultracold neutrons (UCN) is described. The experimental technique relies on Ramsey's method of separated oscillatory fields, using UCN in vacuum with the apparatus at ambient temperature. In the first phase, R&D towards the upgrade of the...
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In: Nuclear Instruments and Methods in Physics Research Section A, 2009///doi: 10.1016/j.nima.2009.07.079
High precision mapping of weak magnetic fields is of interest for several branches of pure and applied research. This paper presents a resume of the progress made at Fribourg in adapting laboratory style laser-pumped optical Cs magnetometers to multisensor field mapping problems. Progress has been made in sensor head design and manufacture, laser beam splitting and control, and signal treatment...
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In: Nuclear Instruments and Methods in Physics Research Section A, 2009///doi: 10.1016/j.nima.2009.07.047
The existence of a mirror world holding a copy of our ordinary particle spectrum could lead to oscillations between the neutron (n) and its mirror partner (n′). Such oscillations could manifest themselves in storage experiments with ultracold neutrons whose storage lifetime would depend on the applied magnetic field. Here, extended details and measurements from the first dedicated experimental...
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