Research on 3He spin filter cells made of quartz glass

Hutanu, Vladimir; Rupp, A.

doi:10.1016/j.physb.2004.10.055

Cited by 8 publications

(9 citation statements)

References 8 publications

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“…The observation of the field dependence of T 1 was also reported for cells that did not contain alkali metal (Hutanu and Rupp, 2005;Schmiedeskamp et al, 2006b), seemingly inconsistent with the earlier observation of the field dependence of T 1 , which requires the presence of alkali metal in the cell (Jacob et al, 2001). It was speculated that the ferromagnetic impurities were brought into the cell during the cell fabrication process.…”

Section: B Wall Relaxation Of 3 Hecontrasting

confidence: 78%

Wall interactions of spin-polarized atoms

2021

Rev. Mod. Phys.

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Spin-polarized atoms have applications in many areas such as biological magnetic resonance imaging, optical magnetometry, atomic clocks and fundamental symmetry studies. Polarized atoms are often held in a container, most commonly a glass cell. Their interactions with the walls of the container during their collisions with the walls are often the main cause of spin relaxation, which determines the ultimate attainable polarization, and frequency shift, which for example affects the long term frequency stability in atomic clocks. This paper presents a critical review of the studies done in the past six decades of the wall interactions of spin-polarized atoms, including the hydrogen atom, alkali metal atoms, and diamagnetic atoms with 1 S0 ground states such as mercury, cadmium and noble gas atoms. It summarizes the progress that has been made in understanding the nature of wall interactions and the physical mechanisms of spin relaxation and frequency shift due to wall collisions. It also points out those issues, particularly in connection with the widely used anti-relaxation coatings, that remain to be understood. CONTENTSI. Introduction 1 II. Wall Interactions of Spin-Polarized Diamagnetic Atoms with 1 S 0 Ground States and Nuclear Spins I ≥ 1 2 A. The nature of the wall interactions 2 B. Quadrupole wall interaction − theory 3 1. Boundary condition 3 2. Perturbation theory 4 C. Quadrupole wall interaction − experiment 5 III. Wall Interactions of Spin-Polarized Noble Gas Atoms with Nuclear Spins I = 1/2 8 A. The nature of the wall interactions 8 B. Wall relaxation of 3 He 9 C. Wall relaxation of 129 Xe 11 1. Mechanisms 11 2. Theory 12 3. Experiments 13 D. Cross polarization 13

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Section: B Wall Relaxation Of 3 Hecontrasting

confidence: 78%

Wall interactions of spin-polarized atoms

2021

Rev. Mod. Phys.

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“…Thus one could not expect to see the effect as distinct as in Pyrex. Nevertheless a strong influence of external magnetic fields on the relaxation time constant T1 has been found also in quartz glass cells [2]. Moreover the phenomenon has been observed both in Cs-coated and in bare-wall cells.…”

Section: Introductionmentioning

confidence: 93%

“…Physica B 397, 185-187 (2007) of nAm 2 and cannot be fitted anymore as a single magnetic dipole (Fig. 3).…”

Section: Mu-metal Shieldingmentioning

confidence: 99%

SQUID measurements of remanent magnetisation in refillable 3He spin-filter cells (SFC)

Hutanu

Rupp

Sander‐Thömmes

2007

Physica B: Condensed Matter

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A strong influence of external magnetic fields on the relaxation time constant T1 of glass cells serving as reservoirs for polarised 3 He, observed for various alkali metal coated cells made of different glass types, was initially associated with the presence of a large number of ferromagnetic clusters on the glass surface. Later experiments showed the presence of the socalled "T1 hysteresis" phenomenon with a similar distinctiveness also in uncoated cells made of pure synthetic quartz glass. It suggests that the origin of such a relaxation is a macroscopic magnetisation in the bulk of the cell. We present the results of a multi SQUID system investigation on magnetised and non-magnetised quartz glass cells, Cs-coated as well as bare-wall, to be used as neutron spin filters at HMI Berlin. The presence of a macroscopic remanent magnetic moment in the cells after their exposition to external magnetic fields has been experimentally shown. More than 80% of the remanent magnetic moment of the magnetised cells was found to be concentrated in the region of the glass valves. SQUID measurements reveal the existence of some remanent magnetisation in all valve parts and also in the vacuum grease, but most magnetic are the plastic parts and the O-ring. Different valve and sealing types have been compared in order to find the less magnetisable one.© He relaxation in the magnetised cells to the presence of a large number of ferromagnetic relaxation centres, assumed to be created by a reaction of Rb with iron-containing impurities on the glass surface. These results stimulated us to start with investigations on the magnetic field influence on the relaxation behaviour in refillable (valved) cells made of quartz glass. The concentration of Fe impurities in quartz glass is much lower than in borosilicate or aluminosilicate glasses, (0.2 ppm in quartz glass compared to 210 ppm in GE 180). Thus one could not expect to see the effect as distinct as in Pyrex. Nevertheless a strong influence of external magnetic fields on the relaxation time constant T1 has been found also in quartz glass cells [2]. Moreover the phenomenon has been observed both in Cs-coated and in bare-wall cells. According to Ref.[3], the relaxation mechanism induced by an exposition of a quartz glass cell to an external magnetic field which exceeds only a few hundred Gauss is much stronger than the initial surface relaxation. It can only be removed by degaussing the * Corresponding author. Present address: TUM FRM II,

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“…Sapphire (Chen et al , 2011; Masuda et al , 2005) and silicon-windowed Pyrex cells (Chen et al , 2011) have also been investigated for SEOP, but use has been limited due to relaxation issues. For MEOP cells, which do not need to be heated, both quartz and silicon-windowed Pyrex cells are routinely used (Hutanu and Rupp, 2005; Lelievre-Berna, 2007). Neutron transmission and scattering from glasses are important practical issues for NSFs and have been studied by various groups (Babcock et al , 2014; Chen et al , 2004; Chupp et al , 2007; Sakaguchi et al , 2011b).…”

Section: Neutron Spin-filtersmentioning

confidence: 99%

Optically polarizedHe3

et al. 2017

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This article reviews the physics and technology of producing large quantities of highly spin-polarized 3He nuclei using spin-exchange (SEOP) and metastability-exchange (MEOP) optical pumping. Both technical developments and deeper understanding of the physical processes involved have led to substantial improvements in the capabilities of both methods. For SEOP, the use of spectrally narrowed lasers and K-Rb mixtures has substantially increased the achievable polarization and polarizing rate. For MEOP nearly lossless compression allows for rapid production of polarized 3He and operation in high magnetic fields has likewise significantly increased the pressure at which this method can be performed, and revealed new phenomena. Both methods have benefitted from development of storage methods that allow for spin-relaxation times of hundreds of hours, and specialized precision methods for polarimetry. SEOP and MEOP are now widely applied for spin-polarized targets, neutron spin filters, magnetic resonance imaging, and precision measurements.

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Research on 3He spin filter cells made of quartz glass

Cited by 8 publications

References 8 publications

Wall interactions of spin-polarized atoms

Wall interactions of spin-polarized atoms

SQUID measurements of remanent magnetisation in refillable 3He spin-filter cells (SFC)

Optically polarizedHe3

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