Relaxation of spin polarized 3He by magnetized ferromagnetic contaminants

Schmiedeskamp, Jörg; Elmers, Hans‐Joachim; Heil, W.; Otten, Ernst W.; Sobolev, Yu.; Kilian, Wolfgang; Rinneberg, H.; Sander‐Thömmes, Tilmann; Seifert, F.; Zimmer, J.

doi:10.1140/epjd/e2006-00052-0

Cited by 36 publications

(30 citation statements)

References 9 publications

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“…The use of two coil pairs was chosen in order to manipulate the sample spins, e.g., π/2 spin-flip. The longitudinal relaxation times of helium and xenon in cells made from lowrelaxation GE180 glass [20][21][22] [23]. At present, the relatively short T 1,Xe wall relaxation time of 129 Xe limits the total observation time T of free spin-precession in our 3 He/ 129 Xe clock comparison experiments.…”

Section: Basic Layout Of Experimental Setup and Principle Of Measurementmentioning

confidence: 76%

Spin clocks: Probing fundamental symmetries in nature

et al. 2013

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The detection of the free precession of co-located 3 He/ 129 Xe nuclear spins (clock comparison) is used as ultra-sensitive probe for non-magnetic spin interactions, since the magnetic dipole interaction (Zeeman-term) drops out in the weighted frequency difference, i.e., ω = ω He - Features of frequency standards and clocksSince Galileo Galilei and Christiaan Huygens invented the pendulum clock, time and frequency have been the quantities that we can measure with the highest precision. Since 1967 the Cs atomic clock defines our unit of time, the second, as the period during which a cesium-133 atom oscillates 9,192,631,770 number of cycles on the hyperfine clock transition |F = 4, m F = 0 → |F = 3, m F = 0 in the 6 2 S 1/2 atomic ground state. Cesium atomic clocks have been gradually improved to the point where modern cesium-fountain clocks realize the definition of the second with a relative uncertainty of about 4 × 10 −16 [1]. In the near future, the cesium clock defining the fundamental timing reference will be replaced with an optical clock, since suppression of systematic effects shifting the frequency of a standard is greatly facilitated by the use of higher frequencies.Thanks to the incredible high relative accuracy of frequency determination, atomic clocks may touch the μHz range on an absolute scale, but will essentially not go far below.To address fundamental questions in physics often associated with the experimental search for violation of fundamental symmetries in nature, much smaller frequencies or frequency shifts as a result of tiny changes in the clock transition must be tracked. From that point of view it is more appropriate to develop a "clock" that oscillates at low frequencies (∼10 Hz), but shows the same relative accuracy as a Cs atomic clock. Thus, frequency shifts in the pHz range caused by hypothetical interaction potentials might be accessible."Spin clocks" which are based on nuclear spin precession are the most promising approach to reach such sensitivity limits. The ,,spin clock" described here is based on the detection of free spin-precession of gaseous, nuclear spin-polarized 3 He or 129 Xe samples [2]. Like in a free induction decay (FID) measurement, the decay of the transverse magnetization is monitored and the Larmor frequency ω of the precessing sample magnetization is related to the magnetic field B 0 through ω = γ · B 0 , where γ is the gyromagnetic ratio of the corresponding nucleus. Since this type of clock will preferably operate at low magnetic fields and thus at low frequencies, using a SQUID as magnetic field detector is appropriate due to its high sensitivity in that spectral range. The 3 He/ 129 Xe nuclear spins are polarized by means of optical pumping. Thus, the nuclear polarization obtained exceeds the Boltzmann polarization as used in typical NMR experiments by four to five orders of magnitude.

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Section: Basic Layout Of Experimental Setup and Principle Of Measurementmentioning

confidence: 76%

Spin clocks: Probing fundamental symmetries in nature

et al. 2013

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“…The distance d from the centre of the cell to the monitoring SQUID was d  6 cm. The longitudinal relaxation time T 1 of the cell made from low-relaxation GE180 glass [28][29][30] had been measured before to be T 1 = 85±5 h in a conventional NMR setup. The gas was optically pumped by means of a 2W Yb-doped fibre laser (=1083 nm) and the polarization build-up along the x-axis could be monitored optically by analysing the circular polarization of the 668 nm fluorescence line of the weak discharge spectrum maintained during the optical pumping process [31].…”

Section: Methodsmentioning

confidence: 99%

Ultra-sensitive magnetometry based on free precession of nuclear spins

Gemmel¹,

Heil²,

Karpuk³

et al. 2010

Eur. Phys. J. D

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119

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We discuss the design and performance of a very sensitive low-field magnetometer based on the detection of free spin precession of gaseous, nuclear polarized 3 He or 129 Xe samples with a SQUID as magnetic flux detector. The device will be employed to control fluctuating magnetic fields and gradients in a new experiment searching for a permanent electric dipole moment of the neutron as well as in a new type of 3 He/ 129 Xe clock comparison experiment which should be sensitive to a sidereal variation of the relative spin precession frequency. Characteristic spin precession times after one day. Even in that sensitivity range, the magnetometer performance is statistically limited, and noise sources inherent to the magnetometer are not limiting. The reason is that free precessing 3 He ( 129 Xe) nuclear spins are almost completely decoupled from the environment. That makes this type of magnetometer in particular attractive for precision field measurements where a long-term stability is required.

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“…Gas management has to carefully avoid relaxation losses at all stages, from the preparation of the polarized gas until the end of the image acquisition. Magnetic relaxation induced by walls of gas containers is now well understood and controlled [73,74,75], and all materials in contact with the gas (tubes, valves, mouthpieces or respiratory masks...) must be selected with care. Magnetic relaxation can also occur in the bulk of the gas due to atomic diffusion in inhomogeneous magnetic field, with a typical rate:…”

Section: Specific Features Of Imaging With Polarized Gasesmentioning

confidence: 99%

Magnetic Resonance Imaging: From Spin Physics to Medical Diagnosis

Nacher

2009

The Spin

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Abstract. Two rather similar historical evolutions are evoked, each one originating in fundamental spin studies by physicists, and ending as magnetic resonance imaging (MRI), a set of invaluable tools for clinical diagnosis in the hands of medical doctors. The first one starts with the early work on nuclear magnetic resonance, the founding stone of the usual proton-based MRI, of which the basic principles are described. The second one starts with the optical pumping developments made to study the effects of spin polarization in various fundamental problems. Its unexpected outcome is a unique imaging modality, also based on MRI, for the study of lung physiology and pathologies.

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Relaxation of spin polarized 3He by magnetized ferromagnetic contaminants

Cited by 36 publications

References 9 publications

Spin clocks: Probing fundamental symmetries in nature

Spin clocks: Probing fundamental symmetries in nature

Ultra-sensitive magnetometry based on free precession of nuclear spins

Magnetic Resonance Imaging: From Spin Physics to Medical Diagnosis

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