0000000000041367
AUTHOR
Sergei Karpuk
Magnetized boxes for housing polarized spins in homogeneous fields
Abstract We present novel types of permanently magnetized as well as current powered boxes built from soft-ferromagnetic materials. They provide shielded magnetic fields which are homogeneous within a large fraction of the enclosed volume, thus minimizing size, weight, and costs. For the permanently magnetized solutions, homogenization is achieved either by an optimized distribution of the permanent field sources or by jacketing the field with a soft-ferromagnetic cylindrical shell which is magnetized in parallel to the enclosed field. The latter principle may be applied up to fields of about 0.1 T. With fields of about 1 mT, such boxes are being used for shipping spin-polarized 3 He worldw…
Test of Time Dilation Using StoredLi+Ions as Clocks at Relativistic Speed
We present the concluding result from an Ives-Stilwell-type time dilation experiment using 7Li+ ions confined at a velocity of β=v/c=0.338 in the storage ring ESR at Darmstadt. A Λ-type three-level system within the hyperfine structure of the 7Li+3S1 →3P2 line is driven by two laser beams aligned parallel and antiparallel relative to the ion beam. The lasers' Doppler shifted frequencies required for resonance are measured with an accuracy of <4×10(-9) using optical-optical double resonance spectroscopy. This allows us to verify the special relativity relation between the time dilation factor γ and the velocity β, γ√1-β2=1 to within ±2.3×10(-9) at this velocity. The result, which is singled …
Spin clocks: Probing fundamental symmetries in nature
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 (C…
Test of Time Dilation Using Stored Li+ Ions as Clocks at Relativistic Speed
We present the concluding result from an Ives-Stilwell-type time dilation experiment using 7Li+ ions confined at a velocity of β=v/c=0.338 in the storage ring ESR at Darmstadt. A Λ-type three-level system within the hyperfine structure of the 7Li+3S1 → 3P2 line is driven by two laser beams aligned parallel and antiparallel relative to the ion beam. The lasers’ Doppler shifted frequencies required for resonance are measured with an accuracy of 2=1 to within ±2.3×10−9 at this velocity. The result, which is singled out by a high boost velocity β, is also interpreted within Lorentz invariance violating test theories.
Toward a New Test of the Relativistic Time Dilation Factor by Laser Spectroscopy of Fast Ions in a Storage Ring
The frequency measurement of Doppler-shifted optical lines of ions circulating in a storage ring at high speed permits a sensitive test of the relativistic Doppler-formula and, hence, the time dilation factor γSR of special relativity. Previous measurements at the storage ring TSR with 7Li+ at v = 0.065c gave a new, improved limit, but were hampered by the large observed linewidth, exceeding the natural width 15-fold. Recently we have identified the broadening to be caused by velocity-changing processes in the storage ring. Saturation spectroscopy has proven to be largely immune against these effects and has yielded linewidths only a few MHz larger than the natural one. This is the major in…
Test of relativistic time dilation with fast optical atomic clocks at different velocities
Time dilation is one of the most fascinating aspects of special relativity as it abolishes the notion of absolute time. It was first observed experimentally by Ives and Stilwell in 1938 using the Doppler effect. Here we report on a method, based on fast optical atomic clocks with large, but different Lorentz boosts, that tests relativistic time dilation with unprecedented precision. The approach combines ion storage and cooling with optical frequency counting using a frequency comb. 7Li+ ions are prepared at 6.4% and 3.0% of the speed of light in a storage ring, and their time is read with an accuracy of 2×10−10 using laser saturation spectroscopy. The comparison of the Doppler shifts yield…
The dynamics of bunched laser-cooled ion beams at relativistic energies
We discuss the axial dynamics of laser-cooled relativistic C3+ ion beams at moderate bunching voltages. Schottky noise spectra measured at a beam energy of 122 MeV/u are compared to simulations of the axial beam dynamics. Ions confined in the bucket are addressed by the narrow-band force of a laser beam counter-propagating to the ion beam, while the laser frequency is detuned relatively to the cooling transition frequency in the rest frame of the bucket. At large detuning comparable to the momentum acceptance of the bucket, the axial dynamics can be well explained by the secular motion of individual non-interacting ions. At small detuning, corresponding to a small axial momentum spread Δpax…
Polarization-Dependent Disappearance of a Resonance Signal -- Indication for Optical Pumping in a Storage Ring?
We report on laser spectroscopic measurements on Li$^+$ ions in the experimental storage ring ESR at the GSI Helmholtz Centre for Heavy Ion Research. Driving the $2s\,^3\!{S}_1\;(F=\frac{3}{2}) \,\leftrightarrow\,2p\,^3\!P_2\;(F=\frac{5}{2}) \leftrightarrow 2s\,^3\!{S}_1\;(F=\frac{5}{2})$ $\Lambda$-transition in $^7$Li$^+$ with two superimposed laser beams it was found that the use of circularly polarized light leads to a disappearance of the resonance structure in the fluorescence signal. This can be explained by optical pumping into a dark state of polarized ions. We present a detailed theoretical analysis of this process that supports the interpretation of optical pumping and demonstrate…
Measurement of gas transport kinetics in high-frequency oscillatory ventilation (HFOV) of the lung using hyperpolarized 3He magnetic resonance imaging
PURPOSE: To protect the patient with acute respiratory distress syndrome from ventilator associated lung injury (VALI) high-frequency oscillatory ventilation (HFOV) is used. Clinical experience has proven that HFOV is an efficient therapy when conventional artificial ventilation is insufficient. However, the optimal settings of HFOV parameters, eg, tidal volumes, pressure amplitudes and frequency for maximal lung protection, and efficient gas exchange are not established unambiguously. METHODS: In this work magnetic resonance imaging (MRI) with hyperpolarized (3)He was employed to visualize the redistribution of gas within the cadaver pig lung during HFOV. The saturated slice method was use…
A new limit of the 129 Xenon Electric Dipole Moment
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.
Improved test of time dilation in special relativity.
An improved test of time dilation in special relativity has been performed using laser spectroscopy on fast ions at the heavy-ion storage-ring TSR in Heidelberg. The Doppler-shifted frequencies of a two-level transition in 7 Li + ions at v = 0.064c have been measured in the forward and backward direction to an accuracy of Δν/ν = 1 × 10 - 9 using collinear saturation spectroscopy. The result confirms the relativistic Doppler formula and sets a new limit of 2.2 × 10 - 7 for deviations from the time dilation factor γ S R = (1 - ν 2 /c 2 ) - 1 / 2 .
Bimodal velocity distribution of atoms released from nanosecond ultraviolet laser ablation
We have investigated the velocity distributions of atoms released from a metallic gadolinium surface by UV laser ablation. The fluences of the nanosecond laser pulses were chosen for a pure release of neutrals and at a higher fluence level for the release of both neutrals and ions. In both cases a thermal Maxwell-Boltzmann slope has been observed for the low velocities, whereas for high velocities strong deviations from a thermal distribution have been seen. The observed velocity distribution has been explained by a bimodal structure including a thermal phase and a shockwave driven ``blow-off'' phase.
Systematic T1 improvement for hyperpolarized 129xenon
The spin-lattice relaxation time T1 of hyperpolarized (HP)-(129)Xe was improved at typical storage conditions (i.e. low and homogeneous magnetic fields). Very long wall relaxation times T(1)(wall) of about 18 h were observed in uncoated, spherical GE180 glass cells of ∅=10 cm 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/T1(Xe-Xe) due to van der Waals molecules was invest…
Search for Spin-Dependent Short-Range Interaction with an 3He/129Xe Clock Comparison Experiment
We performed an experiment to search for a new spin-dependent P- and T-violating nucleon–nucleon interaction [Formula: see text] which is mediated by light pseudoscalar bosons such as axions or axionlike particles. This interaction causes a shift [Formula: see text] in the precession frequency of nuclear spin polarized gases in the presence of an unpolarized mass. In order to measure this frequency shift a 3He/[Formula: see text]Xe comagnetometer was used which is based on the detection of free precession of 3He and [Formula: see text]Xe nuclear spins using SQUIDs as detectors. For the upper limit of [Formula: see text] we obtained 7.1[Formula: see text]nHz. With this value, an upper limit…
Iodine hyperfine structure and absolute frequency measurements at 565, 576, and 585nm
Abstract The hyperfine structure splittings of the P(10)14-1, R(15)14-1, and R(99)15-1 transitions at 585 nm, P(62)17-1 at 576 nm, and P(80)21-1 at 565 nm in 127 I 2 are measured by heterodyne spectroscopy using two dye lasers. In addition, the absolute frequencies of the hyperfine components P(10)14-1 a 15 and P(80)21-1 a 10 are determined using a self-referenced frequency comb. These frequencies are used in an experiment testing relativistic time dilation by laser spectroscopy on a fast ion beam.
Periodic unmixing of a binary metallic vapor
We report on a type of surface structuring after short pulse laser ablation of a binary alloy. We observe the emergence of a concentric ring structure with changing elemental composition. The composition changes are interpreted by condensation of the ambient ablation vapor due to stress wave excitations in the ablation spot.
Multi-color resonance ionization of laser ablated gadolinium at high laser power
Abstract Spectroscopic and analytical properties of a trace analytical method using multi-step resonance ionization at high laser intensities (>kW/cm 2 ) have been investigated with gadolinium as a test element. Strongly saturated transitions are observed, which have been used for a temperature determination of the atoms in the laser ablated plume. Regimes of multi-step resonance ionization and multiphoton ionization could be distinguished. Analytical performances due to resonance enhancement and resulting discrimination against non-resonant background, precision in isotope ratio determination and overall detection efficiency are discussed.
A laser desorption/resonance enhanced photoionisation TOF-system for the spatially resolved trace analysis of elements
Abstract A novel method for direct and spatially resolved elemental trace analysis with high sensitivity and elemental selectivity is presented. The concept is based on the combination of a commercial MALDI-TOF mass spectrometer with a pulsed laser system for resonant postionisation of neutrals. While the MALDI method is usually applied for investigations of large organic compounds and biomolecules, the technique discussed here concerns the low mass range around 1 ⩽ A ⩽ 300. The analytical performances of the setup with respect to mass analysis, spatial resolution and overall detection efficiency are discussed.