Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

Bulletin of the American Physical Society

Entrainment of lithium atoms into a supersonic beam and magnetic deceleration

Yu Wei Lu, Lukas Gerhard Georg Gradl, Li-Chung Ha, Logan Edward Hillberry, Kevin Melin, Pavel Nagornykh, Jordan Zesch, Mark G. Raizen

Published Jun 8, 2017• 0 citations
OpenAlex

Related papers

Trapping cold molecules and atoms: Simultaneous magnetic deceleration and trapping of cold molecular Oxygen with Lithium atoms

Nitzan Akerman, Michael Karpov, Yair Segev +3 more

Bulletin of the American Physical Society•May 26, 2016•0 citations

Magnetic trapping of decelerated neutral atoms

Harold J. Metcalf

Progress in Quantum Electronics•Jan 1, 1984•12 citations

Trapping of Molecular Oxygen together with Lithium Atoms

Nitzan Akerman, Michael Karpov, Yair Segev +3 more

We demonstrate simultaneous deceleration and trapping of a cold atomic and molecular mixture. This is the first step towards studies of cold atom-molecule collisions at low temperatures as well as application of sympathetic cooling. Both atoms and molecules are cooled in a supersonic expansion and are loaded into a moving magnetic trap that brings them to rest via the Zeeman interaction from an initial velocity of 375 m/s. We use a beam seeded with molecular oxygen, and entrain it with lithium atoms by laser ablation prior to deceleration. The deceleration ends with loading of the mixture into a static quadrupole trap, which is generated by two permanent magnets. We estimate 10^{9} trapped O_{2} molecules and 10^{5} Li atoms with background pressure limited lifetime on the order of 1 sec. With further improvements to lithium entrainment we expect that sympathetic cooling of molecules is within reach.

arXiv:1611.00155•Physical Review Letters•Aug 16, 2017•56 citations

A bright source of cold atoms

Yu Lu

This dissertation describes a general approach of generating a high flux of cold atoms that can be confined in a magneto-optical trap. As an alternative to the state-of-the-art laser cooling method, this approach widens our ability to cool and control atoms without relying on a specific atomic transition and availability of laser. In this dissertation I will discuss the design, construction of the experiment and characterization of a pulsed cold atom source in detail. This work is based on a new paradigm: entrainment of atoms in the carrier gas of a supersonic beam, followed by the magnetic deceleration and trapping. Our methodology is based on the supersonic beam created by the expansion of a dense carrier gas from a pulsed release of gas through a small aperture. Cold noble gas emerging from this pulsed high pressure supersonic nozzle acts as a carrier, into which atoms of interest are then entrained. In our studies with the lithium atoms, up to 10¹¹ atoms per pulse could be entrained into a supersonic beam of helium at a translation temperature of below 100 mK. The supersonic valve is typically operated at a rate of below 1 Hz in the experiment. A much larger flux can be achieved at a higher repetition rate. These atoms are moving at a speed of 500 ms⁻¹ and need to be decelerated almost to a complete stop, in order to be trapped and cooled to quantum degeneracy. A 2.5-meter long moving-trap magnetic decelerator with 480 coil pairs was built and characterized. Atoms moving at a speed around 500 ms⁻¹ were trapped and decelerated to various final velocities ranging from 400 ms⁻¹ to 50 ms⁻¹, at a resulting temperature of 30 mK and a flux of 10⁸ ~ 10⁹ atoms per pulse. This whole process takes place within only 10 ms, at a repetition rate of 100 Hz 10¹⁰ ~ 10¹¹ atoms can be delivered per second. This approach is very general compared to the laser cooling, since most atoms in the periodic table have a magnetic moment in their ground state or can be optically pumped to a long-lived para-magnetic metastable state. In this dissertation, I show the working principle of each component of our experiment and characterize the atom beam at multiple stages. I describe in detail the construction and optimization of our magnetic decelerator, and demonstrate the control and monitoring system with the experiment results. Also implemented in this work is a flexible laser system that is composed of a reference diode laser and two tapered amplifiers to control and probe the internal states of atoms, as well as provide the trapping force. I also explore the optical molasses and chirped cooling techniques which help load the atoms into a magneto-optical trap. The successful demonstration of this method of creating a cold atom source leads us to believe that the magnetically decelerated supersonic atoms will play an important role in the area of cold atom physics

•May 1, 2019•0 citations

A cold and controlled lithium beam for reaction dynamics studies

Xin Wang, Jiayue Li, Lan Liu +5 more

Chemical Physics Letters•Dec 4, 2024•2 citations

A "heat pipe"-style recirculating lithium oven for entrainment into supersonic helium beams

Lukas Gerhard Georg Gradl

This thesis presents the work on a new oven design optimized for the\nentrainment of lithium into a pulsed supersonic beam of helium. The\nproposed oven does not pollute the vacuum with lithium atoms that are\nnot entrained, but instead is designed to capture and recirculate all\natoms that are not carried away by the supersonic beam. The\ntransportation of lithium inside the oven is reminiscent of a heat\npipe, coining the nickname of the oven: Lithium is evaporated in a hot\nreservoir, recondensed at a cold surface, and recirculated to the hot\nreservoir using capillary action.\n\nThe supersonic helium beam is generated by an Even-Lavie valve\nyielding a cold and collimated flow of gas. The supersonic beam can\nbe further collimated by using a skimmer. Two different heat-pipe\noven designs are investigated in this thesis, one for entrainment\ndownstream of the skimmer and on for entrainment upstream of the\nskimmer.\n\nDownstream of the skimmer, the lithium that is carried in the helium\nbeam behind the oven is much hotter and slower than the carrier gas.\nThis is due to the low density of the helium beam past the skimmer,\nwhich does not support enough collisions with the lithium atoms to\nreach equilibrium.\n\nUpstream of the skimmer, the helium density is higher and the beam\nbehaves in part like continuous flow and the interaction with the oven\nheats the supersonic beam considerably. The lithium content in the\nbeam that was measured past the skimmer is faster and hotter than the\nhelium flow. It is also not properly entrained, but pushed along by\nthe helium beam.\n\nFrom these experiments it is obvious, that entrainment depends\ncrucially of the local properties of the supersonic beam at the\nentrainment site. To be more flexible in the choice of this\nparameter, a new design for a heat-pipe oven is proposed, which allows\nfor linear translation along the propagation direction of the beam,\nupstream of the skimmer.

•Jan 1, 2017•0 citations
We demonstrate simultaneous deceleration and trapping of a cold atomic and molecular mixture. This is the first step towards studies of cold atom-molecule collisions at low temperatures as well as application of sympathetic cooling. Both atoms and molecules are cooled in a supersonic expansion and are loaded into a moving magnetic trap that brings them to rest via the Zeeman interaction from an initial velocity of 375 m/s. We use a beam seeded with molecular oxygen, and entrain it with lithium atoms by laser ablation prior to deceleration. The deceleration ends with loading of the mixture into a static quadrupole trap, which is generated by two permanent magnets. We estimate 10^{9} trapped O_{2} molecules and 10^{5} Li atoms with background pressure limited lifetime on the order of 1 sec. With further improvements to lithium entrainment we expect that sympathetic cooling of molecules is within reach.
This dissertation describes a general approach of generating a high flux of cold atoms that can be confined in a magneto-optical trap. As an alternative to the state-of-the-art laser cooling method, this approach widens our ability to cool and control atoms without relying on a specific atomic transition and availability of laser. In this dissertation I will discuss the design, construction of the experiment and characterization of a pulsed cold atom source in detail. This work is based on a new paradigm: entrainment of atoms in the carrier gas of a supersonic beam, followed by the magnetic deceleration and trapping. Our methodology is based on the supersonic beam created by the expansion of a dense carrier gas from a pulsed release of gas through a small aperture. Cold noble gas emerging from this pulsed high pressure supersonic nozzle acts as a carrier, into which atoms of interest are then entrained. In our studies with the lithium atoms, up to 10¹¹ atoms per pulse could be entrained into a supersonic beam of helium at a translation temperature of below 100 mK. The supersonic valve is typically operated at a rate of below 1 Hz in the experiment. A much larger flux can be achieved at a higher repetition rate. These atoms are moving at a speed of 500 ms⁻¹ and need to be decelerated almost to a complete stop, in order to be trapped and cooled to quantum degeneracy. A 2.5-meter long moving-trap magnetic decelerator with 480 coil pairs was built and characterized. Atoms moving at a speed around 500 ms⁻¹ were trapped and decelerated to various final velocities ranging from 400 ms⁻¹ to 50 ms⁻¹, at a resulting temperature of 30 mK and a flux of 10⁸ ~ 10⁹ atoms per pulse. This whole process takes place within only 10 ms, at a repetition rate of 100 Hz 10¹⁰ ~ 10¹¹ atoms can be delivered per second. This approach is very general compared to the laser cooling, since most atoms in the periodic table have a magnetic moment in their ground state or can be optically pumped to a long-lived para-magnetic metastable state. In this dissertation, I show the working principle of each component of our experiment and characterize the atom beam at multiple stages. I describe in detail the construction and optimization of our magnetic decelerator, and demonstrate the control and monitoring system with the experiment results. Also implemented in this work is a flexible laser system that is composed of a reference diode laser and two tapered amplifiers to control and probe the internal states of atoms, as well as provide the trapping force. I also explore the optical molasses and chirped cooling techniques which help load the atoms into a magneto-optical trap. The successful demonstration of this method of creating a cold atom source leads us to believe that the magnetically decelerated supersonic atoms will play an important role in the area of cold atom physics
This thesis presents the work on a new oven design optimized for the\nentrainment of lithium into a pulsed supersonic beam of helium. The\nproposed oven does not pollute the vacuum with lithium atoms that are\nnot entrained, but instead is designed to capture and recirculate all\natoms that are not carried away by the supersonic beam. The\ntransportation of lithium inside the oven is reminiscent of a heat\npipe, coining the nickname of the oven: Lithium is evaporated in a hot\nreservoir, recondensed at a cold surface, and recirculated to the hot\nreservoir using capillary action.\n\nThe supersonic helium beam is generated by an Even-Lavie valve\nyielding a cold and collimated flow of gas. The supersonic beam can\nbe further collimated by using a skimmer. Two different heat-pipe\noven designs are investigated in this thesis, one for entrainment\ndownstream of the skimmer and on for entrainment upstream of the\nskimmer.\n\nDownstream of the skimmer, the lithium that is carried in the helium\nbeam behind the oven is much hotter and slower than the carrier gas.\nThis is due to the low density of the helium beam past the skimmer,\nwhich does not support enough collisions with the lithium atoms to\nreach equilibrium.\n\nUpstream of the skimmer, the helium density is higher and the beam\nbehaves in part like continuous flow and the interaction with the oven\nheats the supersonic beam considerably. The lithium content in the\nbeam that was measured past the skimmer is faster and hotter than the\nhelium flow. It is also not properly entrained, but pushed along by\nthe helium beam.\n\nFrom these experiments it is obvious, that entrainment depends\ncrucially of the local properties of the supersonic beam at the\nentrainment site. To be more flexible in the choice of this\nparameter, a new design for a heat-pipe oven is proposed, which allows\nfor linear translation along the propagation direction of the beam,\nupstream of the skimmer.