High-Flux Beam Source for Cold, Slow Atoms or Molecules

Maxwell, Stephen E.; Brahms, Nathan; deCarvalho, Robert; Glenn, David; Helton, Joel S.; Nguyen, Scott V.; Patterson, David; Petricka, Jalean J.; DeMille, David; Doyle, John M.

doi:10.1103/physrevlett.95.173201

Cited by 180 publications

(214 citation statements)

References 32 publications

(37 reference statements)

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“…Typical parameters for the two sources have been well documented [1,29,30]. For our simulations, we chose parameters listed in Table. III, typical for a neon buffer-gas beam in the hydrodynamic expansion regime.…”

Section: Stark Deceleration Of a Position/velocity Correlated Beammentioning

confidence: 99%

Method for traveling-wave deceleration of buffer-gas beams of CH

et al. 2014

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Cryogenic buffer-gas beams are a promising method for producing bright sources of cold molecular radicals for cold collision and chemical reaction experiments. In order to use these beams in studies of reactions with controlled collision energies, or in trapping experiments, one needs a method of controlling the forward velocity of the beam. A Stark decelerator can be an effective tool for controlling the mean speed of molecules produced by supersonic jets, but efficient deceleration of buffer-gas beams presents new challenges due to longer pulse lengths. Traveling-wave decelerators are uniquely suited to meet these challenges because of their ability to confine molecules in three dimensions during deceleration and their versatility afforded by the analog control of the electrodes. We have created ground state CH(X 2 Π) radicals in a cryogenic buffer-gas cell with the potential to produce a cold molecular beam of 10 11 mol./pulse. We present a general protocol for Stark deceleration of beams with a large position and velocity spread for use with a traveling-wave decelerator. Our method involves confining molecules transversely with a hexapole for an optimized distance before deceleration. This rotates the phase-space distribution of the molecular packet so that the packet is matched to the time varying phase-space acceptance of the decelerator. We demonstrate with simulations that this method can decelerate a significant fraction of the molecules in successive wells of a traveling-wave decelerator to produce energy-tuned beams for cold and controlled molecule experiments.

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Section: Stark Deceleration Of a Position/velocity Correlated Beammentioning

confidence: 99%

Method for traveling-wave deceleration of buffer-gas beams of CH

et al. 2014

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“…[17][18][19] Molecules produced purely from filtering techniques, however, are not necessarily Buffer-gas cooling is another direct cooling method. 20,21 Buffer-gas cooled beams are applicable to nearly any small molecule 13,18,22,23 because only elastic collisions with cold buffer gases are required to translationally and rotationally cool molecules. 22,24 When a buffer-gas beam is operated in the "hydrodynamic" enhancement regime, where the diffusion time of molecules is longer than the characteristic time the buffer gas spends in the production cell, molecules can be efficiently extracted into a beam, resulting in high molecular flux.…”

Section: Introductionmentioning

confidence: 99%

“…20,21 Buffer-gas cooled beams are applicable to nearly any small molecule 13,18,22,23 because only elastic collisions with cold buffer gases are required to translationally and rotationally cool molecules. 22,24 When a buffer-gas beam is operated in the "hydrodynamic" enhancement regime, where the diffusion time of molecules is longer than the characteristic time the buffer gas spends in the production cell, molecules can be efficiently extracted into a beam, resulting in high molecular flux. 13,18 Due to collisions with fast, forward-moving buffer gas in a hydrodynamic beam, molecules are accelerated, or "boosted", to the forward velocity of the buffer gas, v f = 2K B T bg /m bg , where T bg and m bg are the temperature and mass of the buffer gas, respectively.…”

Section: Introductionmentioning

confidence: 99%

“…13,18 Due to collisions with fast, forward-moving buffer gas in a hydrodynamic beam, molecules are accelerated, or "boosted", to the forward velocity of the buffer gas, v f = 2K B T bg /m bg , where T bg and m bg are the temperature and mass of the buffer gas, respectively. 13,22 Although this results in high molecular fluxes and is useful for many applications, the boosted molecular velocity makes direct loading of high densities of molecules into electromagnetic traps infeasible. In contrast, buffer-gas beams operated in the diffusive limit have a much lower forward velocity of v f ,e f f = 2K B T bg /m molecule and a lower molecular flux.…”

Section: Introductionmentioning

confidence: 99%

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A cold and slow molecular beam

Rasmussen

Wright

et al. 2011

Phys. Chem. Chem. Phys.

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Employing a two-stage cryogenic buffer gas cell, we produce a cold, hydrodynamically extracted beam of calcium monohydride molecules with a near effusive velocity distribution. Beam dynamics, thermalization and slowing are studied using laser spectroscopy. The key to this hybrid, effusive-like beam source is a "slowing cell" placed immediately after a hydrodynamic, cryogenic source [Patterson et al., J. Chem. Phys., 2007, 126, 154307]. The resulting CaH beams are created in two regimes. One modestly boosted beam has a forward velocity of v f = 65 m/s, a narrow velocity spread, and a flux of 10 9 molecules per pulse. The other has the slowest forward velocity of v f = 40 m/s, a longitudinal temperature of 3.6 K, and a flux of 5 × 10 8 molecules per pulse.

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“…The capabilities and the universality of our technique are demonstrated by deceleration of three species, CH 3 F, CF 3 H, and CF 3 CCH, from a liquid-nitrogen-cooled source [12] with different initial kinetic energies of the order of 100 K. Output beams with intensities of several 10 9 mm À2 s À1 for molecules with kinetic energies below 1 K are achieved. Even higher intensities are expected for molecules from a supersonic beam or a cryogenic buffer-gas cell [13,14].…”

mentioning

confidence: 99%

Slowing Continuous Molecular Beams in a Rotating Spiral

Osterwalder¹

2014

Physics

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Producing large samples of slow molecules from thermal-velocity ensembles is a formidable challenge. Here we employ a centrifugal force to produce a continuous molecular beam with a high flux at near-zero velocities. We demonstrate deceleration of three electrically guided molecular species, CH 3 F, CF 3 H, and CF 3 CCH, with input velocities of up to 200 m s À1 to obtain beams with velocities below 15 m s À1 and intensities of several 10 9 mm À2 s À1 . The centrifuge decelerator is easy to operate and can, in principle, slow down any guidable particle. It has the potential to become a standard technique for continuous deceleration of molecules.

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High-Flux Beam Source for Cold, Slow Atoms or Molecules

Cited by 180 publications

References 32 publications

Method for traveling-wave deceleration of buffer-gas beams of CH

Method for traveling-wave deceleration of buffer-gas beams of CH

A cold and slow molecular beam

Slowing Continuous Molecular Beams in a Rotating Spiral

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