The detection of the free precession of co‐located 3He/129Xe 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., Δω = ωHe‐ γHe/γXe·ωXe of the respective Larmor frequencies. Recent results are reported on searches for (i) short‐range P‐ and T‐violating interactions between nucleons, and (ii) Lorentz violating signatures by monitoring the Larmor frequencies as the laboratory reference frame rotates with respect to distant stars (sidereal modulation). Finally, a new experimental initiative to search for an electric dipole moment of 129Xe (CP‐violation) is discussed, which strongly benefits from the long spin‐coherence times obtained, reaching T2,He*> 100 h and T2,Xe*> 8 h in case of 3He and 129Xe, respectively.
The detection of the free precession of co‐located 3He/129Xe 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., Δω = ωHe‐ γHe/γXe·ωXe of the respective Larmor frequencies. Recent results are reported on searches for (i) short‐range P‐ and T‐violating interactions between nucleons, and (ii) Lorentz violating signatures by monitoring the Larmor frequencies as the laboratory reference frame rotates with respect to distant stars (sidereal modulation). Finally, a new experimental initiative to search for an electric dipole moment of 129Xe (CP‐violation) is discussed, which strongly benefits from the long spin‐coherence times obtained, reaching T*2,He> 100 h and T*2,Xe> 8 h in case of 3He and 129Xe, respectively.
We report on the first preliminary result of our 129Xe EDM measurement performed by the MIXed collaboration. The aim of this report is to demonstrate the feasibility of a new method to set limits on ...nuclear EDMs by investigating the EDM of the diamagnetic 129Xe atoms. In our setup, hyperpolarized 3He serves as a comagnetometer needed to suppress magnetic field fluctuations. The free induction decay of the two polarized spin species is directly measured by low noise DC SQUIDs, and the weighted phase difference extracted from these measurements is used to determine a preliminary upper limit on the 129Xe EDM.
The PERC (Proton and Electron Radiation Channel) facility is currently under construction at the research reactor FRM II, Garching. It will serve as an intense and clean source of electrons and ...protons from neutron beta decay for precision studies. It aims to contribute to the determination of the Cabibbo-Kobayashi-Maskawa quark-mixing element
V
ud
from neutron decay data and to search for new physics via new effective couplings. PERC's central component is a 12 m long superconducting magnet system. It hosts an 8 m long decay region in a uniform field. An additional high-field region selects the phase space of electrons and protons which can reach the detectors and largely improves systematic uncertainties. We discuss the design of the magnet system and the resulting properties of the magnetic field.
We obtained very long relaxation times
T
1 of up to 120 h for the nuclear polarization of an optically pumped helium 3 gas. The glass containers were internally coated with metallic films such as ...bismuth or cesium. These findings will have applications in the field of helium magnetometers and polarized targets.
Systematic T1 improvement for hyperpolarized 129xenon Repetto, Maricel; Babcock, Earl; Blümler, Peter ...
Journal of magnetic resonance (1997),
March 2015, 2015-Mar, 2015-03-00, 20150301, Letnik:
252
Journal Article
Recenzirano
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•Very long wall relaxation times were obtained reproducibly in uncoated glass cells.•“Aging” process of wall relaxation in the same cell was identified and eliminated.•SF6 and CO2 ...were identified as efficient destroyers of Xe-dimers.•Strong dependence of van der Waals relaxation on the isotope concentration.•In summary this yields storage times for HP-129Xe of 5–7h at low magnetic fields.
The spin–lattice relaxation time T1 of hyperpolarized (HP)-129Xe was improved at typical storage conditions (i.e. low and homogeneous magnetic fields). Very long wall relaxation times T1wall of about 18h were observed in uncoated, spherical GE180 glass cells of ∅=10cm which were free of rubidium and not permanently sealed but attached to a standard glass stopcock. An “aging” process of the wall relaxation was identified by repeating measurements on the same cell. This effect could be easily removed by repeating the initial cleaning procedure. In this way, a constant wall relaxation was ensured. The Xe nuclear spin-relaxation rate 1/T1Xe–Xe due to van der Waals molecules was investigated too, by admixing three different buffer gases (N2, SF6 and CO2). Especially CO2 exhibited an unexpected high efficiency (r) in shortening the lifetime of the Xe–Xe dimers and hence prolonging the total T1 relaxation even further. These measurements also yielded an improved accuracy for the van der Waals relaxation for pure Xe (with 85% 129Xe) of T1Xe–Xe=(4.6±0.1)h. Repeating the measurements with HP 129Xe in natural abundance in mixtures with SF6, a strong dependence of T1Xe–Xe and r on the isotopic enrichment was observed, uncovering a shorter T1Xe–Xe relaxation for the 129Xe in natural composition as compared to the 85% isotopically enriched gas.
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