Stopping supersonic oxygen with a series of pulsed electromagnetic coils: A molecular coilgun

Narevicius, Edvardas; Libson, A.; Parthey, Christian G.; Chavez, Isaac; Narevicius, Julia; Even, U.; Raizen, Mark G.

doi:10.1103/physreva.77.051401

Cited by 132 publications

(139 citation statements)

References 30 publications

(39 reference statements)

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“…This improved the cooling capacity, and enabled the experiment to operate at repetition rates of 10 Hz. Raizen and co-workers also developed a multistage Zeeman decelerator, referred to as the atomic or molecular coil gun, that is based on solenoids encased in high-permeability material to increase the on-axis maximum magnetic field strength [46,47]. Recently, different types of traveling-wave Zeeman decelerators have been developed, which consist of numerous spatially overlapping quadrupole solenoids [28] or a helical wire arrangement to produce the desired magnetic field [26].…”

Section: A Multistage Zeeman Deceleratormentioning

confidence: 99%

Multistage Zeeman decelerator for molecular-scattering studies

Cremers¹,

Chefdeville²,

Janssen³

et al. 2017

Phys. Rev. A

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We present a concept for a multistage Zeeman decelerator that is optimized particularly for applications in molecular beam scattering experiments. The decelerator consists of a series of alternating hexapoles and solenoids, that effectively decouple the transverse focusing and longitudinal deceleration properties of the decelerator. It can be operated in a deceleration and acceleration mode, as well as in a hybrid mode that makes it possible to guide a particle beam through the decelerator at constant speed. The deceleration features phase stability, with a relatively large six-dimensional phase-space acceptance. The separated focusing and deceleration elements result in an unequal partitioning of this acceptance between the longitudinal and transverse directions. This is ideal in scattering experiments, which typically benefit from a large longitudinal acceptance combined with narrow transverse distributions. We demonstrate the successful experimental implementation of this concept using a Zeeman decelerator consisting of an array of 25 hexapoles and 24 solenoids. The performance of the decelerator in acceleration, deceleration, and guiding modes is characterized using beams of metastable helium ( 3 S) atoms. Up to 60% of the kinetic energy was removed for He atoms that have an initial velocity of 520 m/s. The hexapoles consist of permanent magnets, whereas the solenoids are produced from a single hollow copper capillary through which cooling liquid is passed. The solenoid design allows for excellent thermal properties and enables the use of readily available and cheap electronics components to pulse high currents through the solenoids. The Zeeman decelerator demonstrated here is mechanically easy to build, can be operated with cost-effective electronics, and can run at repetition rates up to 10 Hz.

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Section: A Multistage Zeeman Deceleratormentioning

confidence: 99%

Multistage Zeeman decelerator for molecular-scattering studies

Cremers¹,

Chefdeville²,

Janssen³

et al. 2017

Phys. Rev. A

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“…The direct techniques are based on removing thermal energy from a pre-existing ensemble of molecules via collisional thermalization or time-dependent electromagnetic fields. Among the techniques of this kind are cryogenic buffer-gas cooling [5], velocity filtering [10], and Stark and Zeeman deceleration [7][8][9]. The indirect cooling methods are based on creating molecules in ultracold atomic gases via photoassociation [11,12] and sweeping a dc magnetic field across a Feshbach resonance [1].…”

Section: Introductionmentioning

confidence: 99%

“…At present, cold molecular ensembles can be produced by a number of experimental techniques [1,[5][6][7][8][9][10], which can be broadly classified as direct and indirect. The direct techniques are based on removing thermal energy from a pre-existing ensemble of molecules via collisional thermalization or time-dependent electromagnetic fields.…”

Section: Introductionmentioning

confidence: 99%

Collisional properties of cold spin-polarized nitrogen gas: Theory, experiment, and prospects as a sympathetic coolant for trapped atoms and molecules

et al. 2010

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We report a combined experimental and theoretical study of collision-induced dipolar relaxation in a cold spin-polarized gas of atomic nitrogen (N). We use buffer gas cooling to create trapped samples of 14 N and 15 N atoms with densities (5 ± 2) × 10 12 cm −3 and measure their magnetic relaxation rates at milli-Kelvin temperatures. These measurements, together with rigorous quantum scattering calculations based on accurate ab initio interaction potentials for the 7 + u electronic state of N 2 demonstrate that dipolar relaxation in N + N collisions occurs at a slow rate of ∼10 −13 cm 3 /s over a wide range of temperatures (1 mK to 1 K) and magnetic fields (10 mT to 2 T). The calculated dipolar relaxation rates are insensitive to small variations of the interaction potential and to the magnitude of the spin-exchange interaction, enabling the accurate calibration of the measured N atom density. We find consistency between the calculated and experimentally determined rates. Our results suggest that N atoms are promising candidates for future experiments on sympathetic cooling of molecules.

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“…Presently, suitable laser systems are not available in the VUV region for laser cooling. Alternative methods for producing cold atoms, including surface-contact cooling (for H atoms only 4 ), Zeeman deceleration 5,6 , and buffer gas cooling 7 have been applied to various species and recently the formation of a BEC of metastable helium atoms has been demonstrated using a combination of buffer gas cooling and evaporative cooling 8 . Some of these techniques could in principle be applied to halogen atoms too, but there have been no such studies to date.…”

Section: Introductionmentioning

confidence: 99%

Production of cold bromine atoms at zero mean velocity by photodissociation

Doherty

Bell

Softley

et al. 2011

Phys. Chem. Chem. Phys.

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The production of a translationally cold (T o 1 K) sample of bromine atoms with estimated densities of up to 10 8 cm À3 using photodissociation is presented. A molecular beam of Br 2 seeded in Kr is photodissociated into Br + Br* fragments, and the velocity distribution of the atomic fragments is determined using (2 + 1) REMPI and velocity map ion imaging. By recording images with varying delay times between the dissociation and probe lasers, we investigate the length of time after dissociation for which atoms remain in the laser focus, and determine the velocity spread of those atoms. By careful selection of the photolysis energy, it is found that a fraction of the atoms can be detected for delay times in excess of 100 ms. These are atoms for which the fragment recoil velocity vector is directly opposed and equal in magnitude to the parent beam velocity leading to a resultant lab frame velocity of approximately zero. The FWHM velocity spreads of detected atoms along the beam axis after 100 ms are less than 5 ms À1 , corresponding to temperatures in the milliKelvin range, opening the possibility that this technique could be utilized as a slow Br atom source.

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Stopping supersonic oxygen with a series of pulsed electromagnetic coils: A molecular coilgun

Abstract: We report the stopping of a molecular oxygen beam, using a series of pulsed electromagnetic coils. A series of coils is fired in a timed sequence to bring the molecules to near rest, where they are detected with a quadrupole mass spectrometer. Applications to cold chemistry are discussed.

Cited by 132 publications

References 30 publications

Multistage Zeeman decelerator for molecular-scattering studies

Multistage Zeeman decelerator for molecular-scattering studies

Collisional properties of cold spin-polarized nitrogen gas: Theory, experiment, and prospects as a sympathetic coolant for trapped atoms and molecules

Production of cold bromine atoms at zero mean velocity by photodissociation

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