In: Physical Review D, 2015, vol. 92, no. 9, p. 092003
We present for the first time a detailed and comprehensive analysis of the experimental results that set the current world sensitivity limit on the magnitude of the electric dipole moment (EDM) of the neutron. We have extended and enhanced our earlier analysis to include recent developments in the understanding of the effects of gravity in depolarizing ultracold neutrons; an improved calculation...
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In: The European Physical Journal D, 2015, vol. 69, no. 11, p. 1–11
We report on extensive studies on the intrinsic sensitivity of a combined ³He/Cs magnetometer. The magnetometer relies on the detection of the free spin precession of nuclear spin polarized ³He by optically pumped cesium magnetometers. We characterize the relevant processes involved in the detection and quantify their impact on the total sensitivity of the magnetometer. An expression is derived...
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In: The European Physical Journal A, 2015, vol. 51, no. 11, p. 1–10
We report on the design and first tests of a device allowing for measurement of ultracold neutrons polarisation by means of the simultaneous analysis of the two spin components. The device was developed in the framework of the neutron electric dipole moment experiment at the Paul Scherrer Institute. Individual parts and the entire newly built system have been characterised with ultracold...
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In: Physical Review Letters, 2015, vol. 115, no. 16, p. 162502
We describe a spin-echo method for ultracold neutrons (UCNs) confined in a precession chamber and exposed to a |B0|=1 μT magnetic field. We have demonstrated that the analysis of UCN spin-echo resonance signals in combination with knowledge of the ambient magnetic field provides an excellent method by which to reconstruct the energy spectrum of a confined ensemble of neutrons. The method...
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In: The European Physical Journal D, 2015, vol. 69, no. 8, p. 1–12
We report on the design and performance of a highly sensitive combined ³He/Cs magnetometer for the absolute measurement of magnetic fields. The magnetometer relies on the magnetometric detection of the free spin precession of nuclear spin polarized ³He gas by optically pumped cesium magnetometers. We plan to deploy this type of combined magnetometer in an experiment searching for a permanent...
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In: The European Physical Journal D, 2015, vol. 69, no. 5, p. 1–10
We present a laser-based atomic magnetometer that allows inferring the modulus of a magnetic field from the free Larmor precession of spin-oriented Cs vapour atoms. The detection of free spin precession (FSP) is not subject to systematic readout errors that occur in phase feedback-controlled magnetometers in which the spin precession is actively driven by an oscillating field or a modulation of...
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In: Physics Letters B, 2015, vol. 745, p. 58–63
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In: Journal of Magnetism and Magnetic Materials, 2015, vol. 379, p. 137–150
The discrimination of immobilised superparamagnetic iron oxide nanoparticles (SPIONs) against SPIONs in fluid environments via their magnetic relaxation behaviour is a powerful tool for bio-medical imaging. Here we demonstrate that a gradiometer of laser-pumped atomic magnetometers can be used to record accurate time series of the relaxing magnetic field produced by pre-polarised SPIONs. We have...
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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: EPJ Techniques and Instrumentation, 2014, vol. 1, no. 1, p. 8
We have developed a highly sensitive 3He magnetometer for the accurate measurement of the magnetic field in an experiment searching for an electric dipole moment of the neutron. By measuring the Larmor frequency of nuclear spin polarized 3He atoms a sensitivity on the femto-Tesla scale can be achieved. A 3He/Cs-test facility was established at the Institute of Physics of the Johannes Gutenberg...
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