Physical Review A

Intense continuous cold-atom source

William Huntington, Jeremy Glick, Michael Borysow, Daniel J. Heinzen

Published Jan 6, 2023• 9 citations

Abstract

The authors demonstrate an intense, continuous cold atomic beam generated via postnozzle seeding of a supersonic ${}^{4}$He jet with ${}^{7}$Li atoms, which is comparable to the highest flux sources based on laser cooling. The technique could potentially be widely applicable to any paramagnetic atom or molecule.

DOI: 10.1103/physreva.107.013302

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An Intense, Continuous Cold Atom Source

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A method for producing a high intensity cold atomic beam is discussed. The method is based on post-nozzle seeding of lithium into a supersonic helium jet.

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Physical Review A

Intense continuous cold-atom source

William Huntington, Jeremy Glick, Michael Borysow, Daniel J. Heinzen

Published Jan 6, 2023• 9 citations

Publisher

Abstract

The authors demonstrate an intense, continuous cold atomic beam generated via postnozzle seeding of a supersonic

{}^{4}

He jet with

{}^{7}

Li atoms, which is comparable to the highest flux sources based on laser cooling. The technique could potentially be widely applicable to any paramagnetic atom or molecule.

DOI: 10.1103/physreva.107.013302

Related papers

An Intense, Continuous Cold Atom Source

Huntington, William, Jeremy J. Glick, Michael Borysow +1 more

We demonstrate an intense, continuous cold atom beam generated via post nozzle seeding of a supersonic helium jet with $^7$ Li atoms. The nozzle is cooled to about 4.4 K to reduce the forward velocity of the atoms. The atomic beam is brought to a focus 175 cm from the nozzle by a 10 cm bore diameter magnetic hexapole lens. Absorption and fluorescence imaging of the focus show a flux of $2.3(4) \times 10^{12}$ atoms/s, brightness of $4.1(7)\times 10^{19}$ $\textrm{m}^{-2}\textrm{s}^{-1}\textrm{sr}^{-1}$ , forward velocity of 211(2) m/s, and longitudinal temperature of 7(3) mK. Results agree with a Monte Carlo simulation of the seeding dynamics and a particle tracing simulation of the atom lens. We project that 10 times higher flux would be possible with improved vacuum system design. Our method should provide a useful high-brightness source for atom-optical and other atomic and molecular physics applications.We demonstrate an intense, continuous cold atom beam generated via post nozzle seeding of a supersonic helium jet with $^7$Li atoms. The nozzle is cooled to about 4.4 K to reduce the forward velocity of the atoms. The atomic beam is brought to a focus 175 cm from the nozzle by a 10 cm bore diameter magnetic hexapole lens. Absorption and fluorescence imaging of the focus show a flux of $2.3(4) \times 10^{12}$ atoms/s, brightness of $4.1(7)\times 10^{19}$ $\textrm{m}^{-2}\textrm{s}^{-1}\textrm{sr}^{-1}$, forward velocity of 211(2) m/s, and longitudinal temperature of 7(3) mK. Results agree with a Monte Carlo simulation of the seeding dynamics and a particle tracing simulation of the atom lens. We project that 10 times higher flux would be possible with improved vacuum system design. Our method should provide a useful high-brightness source for atom-optical and other atomic and molecular physics applications.

arXiv:2208.10584Aug 22, 20220 citations

A High Intensity Cold Atom Source

Jeremy Glick, William Huntington, Daniel J. Heinzen

A method for producing a high intensity cold atomic beam is discussed. The method is based on post-nozzle seeding of lithium into a supersonic helium jet.

Jan 1, 20240 citations

A continuous lithium atomic beam source for cryogenic apparatus

Brady Stoll

We have created an atomic beam source of lithium atoms for use in a cryogenic environment. \nThis beam source is expected to provide a \nflux of 10 to the 18 atoms/s. The main features of this source \nare a reservoir chamber of solid lithium heated with heater wire, creating a lithium gas that \ntravels down an ohmically heated tube and exits as an effusive beam. That beam is directed at \na cold supersonic jet of helium. As lithium atoms enter the helium gas they rapidly thermalize \nand become entrained. The design challenges faced included directing the heat load away from \nthe cold elements of the cryogenic chamber, obtaining the correct temperatures to provide the \ndesired \nflux, and measuring the beam as it exited the reservoir. Through the use of laser induced fluorescence, we believe we have observed capture of lithium by the helium jet. Such a beam source \ncan be used to form an intense cold atom source with the potential future application of serving \nas a pump source for an atom laser.We have created an atomic beam source of lithium atoms for use in a cryogenic environment. \nThis beam source is expected to provide a \nflux of 10 to the 18 atoms/s. The main features of this source \nare a reservoir chamber of solid lithium heated with heater wire, creating a lithium gas that \ntravels down an ohmically heated tube and exits as an effusive beam. That beam is directed at \na cold supersonic jet of helium. As lithium atoms enter the helium gas they rapidly thermalize \nand become entrained. The design challenges faced included directing the heat load away from \nthe cold elements of the cryogenic chamber, obtaining the correct temperatures to provide the \ndesired \nflux, and measuring the beam as it exited the reservoir. Through the use of laser induced fluorescence, we believe we have observed capture of lithium by the helium jet. Such a beam source \ncan be used to form an intense cold atom source with the potential future application of serving \nas a pump source for an atom laser.

Jan 1, 20170 citations

Intense Atomic and Molecular Beams Via Neon Buffer-gas Cooling

David Patterson, Julia Rasmussen, John M. Doyle

We realize a continuous, intense, cold molecular and atomic beam source based on buffer-gas cooling. Hot vapor (up to 600 K) from an oven is mixed with cold (15 K) neon buffer gas, and then emitted into a high-flux beam. The novel use of cold neon as a buffer gas produces a forward velocity distribution and low-energy tail that is comparable to much colder helium-based sources. We expect this source to be trivially generalizable to a very wide range of atomic and molecular species with significant vapor pressure below 1000 K. The source has properties that make it a good starting point for laser cooling of molecules or atoms, cold collision studies, trapping, or nonlinear optics in buffer-gas-cooled atomic or molecular gases. A continuous guided beam of cold deuterated ammonia with a flux of 3×10\$^{11}\$ ND\$_{3}\$ molecules s\$^{−1}\$ and a continuous free-space beam of cold potassium with a flux of 1×10\$^{16}\$ K atoms s\$^{−1}\$ are realized.We realize a continuous, intense, cold molecular and atomic beam source based on buffer-gas cooling. Hot vapor (up to 600 K) from an oven is mixed with cold (15 K) neon buffer gas, and then emitted into a high-flux beam. The novel use of cold neon as a buffer gas produces a forward velocity distribution and low-energy tail that is comparable to much colder helium-based sources. We expect this source to be trivially generalizable to a very wide range of atomic and molecular species with significant vapor pressure below 1000 K. The source has properties that make it a good starting point for laser cooling of molecules or atoms, cold collision studies, trapping, or nonlinear optics in buffer-gas-cooled atomic or molecular gases. A continuous guided beam of cold deuterated ammonia with a flux of 3×10\$^{11}\$ ND\$_{3}\$ molecules s\$^{−1}\$ and a continuous free-space beam of cold potassium with a flux of 1×10\$^{16}\$ K atoms s\$^{−1}\$ are realized.

Jan 1, 200949 citations

Cold beam of Li 7 He 4 dimers

Jeremy Glick, William Huntington, Daniel J. Heinzen

We demonstrate an approach for producing a high-flux beam of $^{7}\mathrm{Li}^{4}\mathrm{He}$ dimers by performing postnozzle seeding of a lithium beam into a supersonic helium expansion. The molecular beam has a longitudinal temperature of 13(6) mK and a continuous flux on the order of ${10}^{11}$ dimers/s confined within a solid angle of 0.16 sr. Monte Carlo simulations of molecular formation based on $\mathit{ab}$ initio quantum scattering calculations are carried out and compared to the experimentally observed molecular flux. Extensions of this work could lead towards a more quantitative understanding of few-body collision processes of alkali and helium atoms.We demonstrate an approach for producing a high-flux beam of $^{7}\mathrm{Li}^{4}\mathrm{He}$ dimers by performing postnozzle seeding of a lithium beam into a supersonic helium expansion. The molecular beam has a longitudinal temperature of 13(6) mK and a continuous flux on the order of ${10}^{11}$ dimers/s confined within a solid angle of 0.16 sr. Monte Carlo simulations of molecular formation based on $\mathit{ab}$ initio quantum scattering calculations are carried out and compared to the experimentally observed molecular flux. Extensions of this work could lead towards a more quantitative understanding of few-body collision processes of alkali and helium atoms.

Physical Review AAug 5, 20240 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 physicsThis 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, 20190 citations

The authors demonstrate an intense, continuous cold atomic beam generated via postnozzle seeding of a supersonic

{}^{4}

He jet with

{}^{7}

Li atoms, which is comparable to the highest flux sources based on laser cooling. The technique could potentially be widely applicable to any paramagnetic atom or molecule.

We demonstrate an intense, continuous cold atom beam generated via post nozzle seeding of a supersonic helium jet with

^7

Li atoms. The nozzle is cooled to about 4.4 K to reduce the forward velocity of the atoms. The atomic beam is brought to a focus 175 cm from the nozzle by a 10 cm bore diameter magnetic hexapole lens. Absorption and fluorescence imaging of the focus show a flux of

2.3(4) \times 10^{12}

atoms/s, brightness of

4.1(7)\times 10^{19}

\textrm{m}^{-2}\textrm{s}^{-1}\textrm{sr}^{-1}

, forward velocity of 211(2) m/s, and longitudinal temperature of 7(3) mK. Results agree with a Monte Carlo simulation of the seeding dynamics and a particle tracing simulation of the atom lens. We project that 10 times higher flux would be possible with improved vacuum system design. Our method should provide a useful high-brightness source for atom-optical and other atomic and molecular physics applications.

We demonstrate an approach for producing a high-flux beam of

^{7}\mathrm{Li}^{4}\mathrm{He}

dimers by performing postnozzle seeding of a lithium beam into a supersonic helium expansion. The molecular beam has a longitudinal temperature of 13(6) mK and a continuous flux on the order of

{10}^{11}

dimers/s confined within a solid angle of 0.16 sr. Monte Carlo simulations of molecular formation based on

\mathit{ab}

initio quantum scattering calculations are carried out and compared to the experimentally observed molecular flux. Extensions of this work could lead towards a more quantitative understanding of few-body collision processes of alkali and helium atoms.