LKB - Polarised Helium, Quantum Fluids and Solids

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Regular article

Nuclear hyperpolarization of ³He by magnetized plasmas

Maul A., Blümler P., Nacher P.-J., Otten E., Tastevin G., and Heil W.

Phys. Rev. A (2018) 98, 063405 [12 pages]

We describe a method to hyperpolarize ³He nuclear spins at high magnetic fields (4.7 T) solely by a magnetized plasma.

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The conditions for such a magnetized plasma are fulfilled when the mean free path of the free electrons is much larger than their gyration radius in the rf gas discharge. Investigations are carried out in the 1-15 mbar pressure range with rf excitation at ~100 MHz. Quantitative NMR measurements show that, for different cell sizes and ³He gas densities, nuclear polarizations in the range 1% to 9% are observed. We explain this phenomenon by an alignment-to-orientation conversion mechanism in the excited 2³P state of ³He which is most efficient when the Zeeman and the spin-orbit energies are comparable. The method appears as a very attractive alternative to established laser polarization techniques (spin exchange or metastability exchange optical pumping). Application to ³He nuclear magnetometry with a relative precision of 10-12 is demonstrated.
Part of the experimental setup.

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1) Spherical glass sample containing the ³He gas. 2) Rf discharge coil wound onto the gas container. They both lie inside a short solenoid used for NMR measurements of ³He nuclear polarisation.

Book chapter

History and physical principles of MRI

M. E. Hayden and P.-J. Nacher.

Magn. Reson. Imaging Handbook, 1

(CRC press, 2016 — Ed. Luca SABA)

Cover_chapter

Review article

Optically polarized ³He

T. R. Gentile, P. J. Nacher, B. Saam, and T. G. Walker

Rev. Mod. Phys. 89, 045004 (2017) [59 pp.]

Book

Mécanique Quantique, Tome 1 et Tome 2

Nouvelle édtion

C. Cohen-Tannoudji, B. Diu et F. Laloë

(EDP Sciences – Savoirs Actuels – Sept. 2018)

Book

Comprenons-nous vraiment la mécanique quantique ?

Franck Laloë

(EDP Sciences – Savoirs Actuels – 2nd ed., 2018)

Book

Mécanique Quantique – Tome III

Fermions, bosons, photons, corrélations et intrication

C. Cohen-Tannoudji, B. Diu, F. Laloë

(EDP Sciences – Savoirs Actuels, 2017)

New PhD student

Ali Dia (PSL Research University & St Joseph Universiy of Beirut, Lebanon) has joined the group for co-supervised PhD work on laser optical pumping of helium at low field (Nov. 2017 – Nov. 2020).

WideNMR (2016 — ....)

Analytics
Objectives: Exploration of innovative concepts and applications in a very wide bore NMR spectrometer.
Scientific partners: IRAMIS, CEA Saclay; IFSTTAR; LKB.
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Archives

People
Tous
Polarised He & quantum fluids
Quantum solid & liquid He
  • Franck Laloë
  • Pierre-Jean Nacher
  • Geneviève Tastevin
  • Polar. 3He - Other People
  • Ali Dia
  • Philippe Jacquier
  • Jules Grucker
  • Solid 4He - Other people
Recent Papers

Nuclear hyperpolarization of 3He by magnetized plasmas

A. Maul, P. Blümler, P.-J. Nacher, E. Otten, G. Tastevin, and W. Heil

Phys. Rev. A 98, 063405 (2018)

Dramatic effect of superfluidity on the collapse of ⁴He vapor bubbles An Qu, Azer Trimeche, Philippe Jacquier and Jules Grucker

Phys. Rev. B (2016), 93, 174521

Cavitation Density of Superfluid Helium-4 around 1 K

An Qu, Azer Trimeche, Jacques Dupont-roc, Jules Grucker and Philippe Jacquier

Phys. Rev. B (2015), 91, 214115 (2015)

Surrealistic Bohmian trajectories do not occur with macroscopic pointers

Tastevin G. and Laloë F.

Eur. Phys. J. D 72: 183 (2018)

Optically polarized 3He

T. R. Gentile, P. J. Nacher, B. Saam, and T. G. Walker

Rev. Mod. Phys. 89, 045004 (2017)

History and physical principles of MRI

M.E. Hayden, and P.-J. Nacher

Magn. Reson. Imaging Handbook, 1, CRC press, 2016 (Ed. Luca SABA)

JOB OFFERS

2018-2019 - Master / PhD

 

Polarised helium - Laser optical pumping

We offer several types of internship work for Master students, in connection with our study of laser optical pumping in helium plasmas. A new topic has been opened for PhD: High-field hyperpolarisation in helium plasmas

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2018-2019 - Master / PhD

 

Polarised helium - Low field MRI

Skilled and motivated students are welcome to join our investigations on low field MRI with laser polarised ³He gas or thermally polarised water. Work may focus on the impact of concomitant field gradients on image quality, or investigate the short-pulse limit and revisit the Bloch-Siegert effect in NMR. This topic is open for PhD.

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2018-2019 - Master

 

Polarised helium - Liquid NMR

Skilled and motivated students are welcome to join our investigations on liquid NMR in laser polarised ³He-⁴He dilute solutions. Work will deal with recently observed non linear NMR dynamics and focus on the comparison between experimental and numerical data. This topic is not (yet) open for PhD.

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We are always looking for brillant motivated scientists to join our group.

Check the open positions (see above) or send us your CV for application.

CONTACT

Lhomond

Département de Physique Ecole Normale Supérieure, 24 rue Lhomond, F-75231 Paris Cedex 05  

  •  Jules Grucker  : jules.grucker at lkb.ens.fr
  • Philippe Jacquier : philippe.jacquier at lkb.ens.fr
  • An Qu : an.qu at lkb.ens.fr
  • Franck Laloë : laloe at lkb.ens.fr
  • Pierre-Jean Nacher : nacher at lkb.ens.fr
  • Geneviève Tastevin : genevieve.tastevin at lkb.ens.fr

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