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Kłos J, Tiesinga E. Elastic and glancing-angle rate coefficients for heating of ultracold Li and Rb atoms by collisions with room-temperature noble gases, H 2, and N 2. J Chem Phys 2023; 158:014308. [PMID: 36610981 DOI: 10.1063/5.0124062] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Trapped ultracold alkali-metal atoms can be used to measure pressure in the ultra-high-vacuum and XHV pressure regimes, those with p < 10-6 Pa. This application for ultracold atoms relies on precise knowledge of collision rate coefficients of alkali-metal atoms with residual room-temperature atoms and molecules in the ambient vacuum or with deliberately introduced gasses. Here, we determine combined elastic and inelastic rate coefficients as well as glancing-angle rate coefficients for ultracold 7Li and 87Rb with room-temperature noble gas atoms as well as H2 and 14N2 molecules. Glancing collisions are those processes where only little momentum is transferred to the alkali-metal atom and this atom is not ejected from its trap. Rate coefficients are found by performing quantum close-coupling scattering calculations using ab initio ground-state electronic Born-Oppenheimer potential energy surfaces. The potentials for Li and Rb with noble gas atoms and also for Rb(2S)-H2(XΣg +) and Rb(2S)-N2(X1Σg +) systems are based on the non-relativistic spin-restricted coupled-cluster method with single, double, and noniterative triple excitations [RCCSD(T)]. For Li(2S)-N2(X1Σg +), the potential is computed at the explicitly correlated spin-restricted RCCSD(T)-F12 level. For Rb, Kr, and Xe atoms, scalar relativistic corrections to the core electrons have been included, while second-order spin-orbit corrections from the valence electrons have been estimated. Data for Li-H2 and Li-He were taken from the existing literature. We estimate standard uncertainties of the rate coefficients by comparing rate coefficients calculated using potentials found with electronic basis sets of increasing size, including estimates of relativistic spin-orbit corrections and the uncertainty of the van der Waals coefficients. The relative uncertainties of rate coefficients are 1%-2% with the exception of 7Li or 87Rb colliding with 20Ne. Those have relative uncertainties of 9% and 8%, respectively. We also show that a commonly used semiclassical approximation for the total elastic rate coefficient agrees with the quantum calculations to 10% with the exception of 7Li and 87Rb collisions with H2, where the semiclassical value underestimates the quantum value by 20%.
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Affiliation(s)
- Jacek Kłos
- Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA
| | - Eite Tiesinga
- Joint Quantum Institute, University of Maryland, College Park, Maryland 20742, USA
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2
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Barker DS, Acharya BP, Fedchak JA, Klimov NN, Norrgard EB, Scherschligt J, Tiesinga E, Eckel SP. Precise quantum measurement of vacuum with cold atoms. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2022; 93:121101. [PMID: 36586922 DOI: 10.1063/5.0120500] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Accepted: 10/09/2022] [Indexed: 06/17/2023]
Abstract
We describe the cold-atom vacuum standards (CAVS) under development at the National Institute of Standards and Technology (NIST). The CAVS measures pressure in the ultra-high and extreme-high vacuum regimes by measuring the loss rate of sub-millikelvin sensor atoms from a magnetic trap. Ab initio quantum scattering calculations of cross sections and rate coefficients relate the density of background gas molecules or atoms to the loss rate of ultra-cold sensor atoms. The resulting measurement of pressure through the ideal gas law is traceable to the second and the kelvin, making it a primary realization of the pascal. At NIST, two versions of the CAVS have been constructed: a laboratory standard used to achieve the lowest possible uncertainties and pressures, and a portable version that is a potential replacement for the Bayard-Alpert ionization gauge. Both types of CAVSs are connected to a combined extreme-high vacuum flowmeter and dynamic expansion system to enable sensing of a known pressure of gas. In the near future, we anticipate being able to compare the laboratory scale CAVS, the portable CAVS, and the flowmeter/dynamic expansion system to validate the operation of the CAVS as both a standard and vacuum gauge.
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Affiliation(s)
- Daniel S Barker
- Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Bishnu P Acharya
- Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - James A Fedchak
- Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Nikolai N Klimov
- Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Eric B Norrgard
- Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Julia Scherschligt
- Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Eite Tiesinga
- Quantum Measurement Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Stephen P Eckel
- Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
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3
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Seo M, Do IH, Lee H, Yu DH, Seo S, Hong HG, Han JH, Park SE, Lee SB, Kwon TY, Mun J, Lee JH. Moving-frame imaging of transiting cold atoms for precise long-range transport. OPTICS EXPRESS 2022; 30:25707-25717. [PMID: 36237095 DOI: 10.1364/oe.464087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/19/2022] [Accepted: 06/20/2022] [Indexed: 06/16/2023]
Abstract
Transporting cold atoms between interconnected vacuum chambers is an important technique for increasing the versatility of cold atom setups, particularly for those that couple atoms to photonic devices. In this report, we introduce a method where we are able to image the atoms at all points during transport via moving optical dipole trap. Cooled 87Rb atoms are transported ∼50 cm into an auxiliary vacuum chamber while being monitored with a moving-frame imaging system for which in-situ characterization of the atom transport is demonstrated. Precise positioning of the atoms near photonic devices is also tested across several tapered fibers showing an axial positioning resolution of ∼450 μm.
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4
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Afek G, Carney D, Moore DC. Coherent Scattering of Low Mass Dark Matter from Optically Trapped Sensors. PHYSICAL REVIEW LETTERS 2022; 128:101301. [PMID: 35333080 DOI: 10.1103/physrevlett.128.101301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/05/2021] [Accepted: 01/21/2022] [Indexed: 06/14/2023]
Abstract
We propose a search for low mass dark matter particles through momentum recoils caused by their scattering from trapped, nanometer-scale objects. Our projections show that even with a modest array of femtogram-mass sensors, parameter space beyond the reach of existing experiments can be explored. The case of smaller, attogram-mass sensors is also analyzed-where dark matter can coherently scatter from the entire sensor-enabling a large enhancement in the scattering cross-section relative to interactions with single nuclei. Large arrays of such sensors have the potential to investigate new parameter space down to dark matter masses as low as 10 keV. If recoils from dark matter are detected by such sensors, their inherent directional sensitivity would allow an unambiguous identification of a dark matter signal.
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Affiliation(s)
- Gadi Afek
- Wright Laboratory, Department of Physics, Yale University, New Haven, Connecticut 06520, USA
| | - Daniel Carney
- Physics Division, Lawrence Berkeley National Laboratory, Berkeley, California 94720, USA
| | - David C Moore
- Wright Laboratory, Department of Physics, Yale University, New Haven, Connecticut 06520, USA
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5
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Eckel S, Barker DS, Fedchak J, Newsome E, Scherschligt J, Vest R. A constant pressure flowmeter for extreme-high vacuum. METROLOGIA 2022; 59:10.1088/1681-7575/ac7927. [PMID: 36733422 PMCID: PMC9890398 DOI: 10.1088/1681-7575/ac7927] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
We demonstrate operation of a constant-pressure flowmeter capable of generating and accurately measuring flows as low as 2 × 10-13 mol/s. Generation of such small flows is accomplished by using a small conductance element with C ≈ 50 nL/s. Accurate measurement then requires both low outgassing materials (< 1 × 10-15 mol/s) and small volume changes (≈ 70 μL). We outline the present flowmeter's construction, detail its operation, and quantify its uncertainty. The type-B uncertainty is < 0.2 % (k = 1) over the entire operating range. In particular, we present an analysis of its hydraulic system, and quantify the shift and uncertainty due to the slightly compressible oil. Finally, we compare our flowmeter against a NIST standard flowmeter, and find agreement to within 0.5 % (k = 2).
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Affiliation(s)
- S Eckel
- Sensor Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - D S Barker
- Sensor Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - J Fedchak
- Sensor Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - E Newsome
- Sensor Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - J Scherschligt
- Sensor Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - R Vest
- Sensor Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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Siegel JL, Barker DS, Fedchak JA, Scherschligt J, Eckel S. A Bitter-type electromagnet for complex atomic trapping and manipulation. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2021; 92:033201. [PMID: 33820059 PMCID: PMC8697703 DOI: 10.1063/5.0026812] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Accepted: 02/12/2021] [Indexed: 06/12/2023]
Abstract
We create a pair of symmetric Bitter-type electromagnet assemblies capable of producing multiple field configurations including uniform magnetic fields, spherical quadruple traps, or Ioffe-Pritchard magnetic bottles. Unlike other designs, our coil allows both radial and azimuthal cooling water flows by incorporating an innovative 3D-printed water distribution manifold. Combined with a double-coil geometry, such orthogonal flows permit stacking of non-concentric Bitter coils. We achieve a low thermal resistance of 4.2(1) °C kW-1 and high water flow rate of 10.0(3) l min-1 at a pressure of 190(10) kPa.
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Affiliation(s)
- J. L. Siegel
- Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - D. S. Barker
- Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - J. A. Fedchak
- Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - J. Scherschligt
- Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - S. Eckel
- Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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7
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Hendricks J, Ahmed Z, Barker D, Douglass K, Eckel S, Fedchak J, Klimov N, Ricker J, Scherschligt J. Quantum-Based Photonic Sensors for Pressure, Vacuum, and Temperature Measurements: A Vison of the Future with NIST on a Chip. MEASUREMENT. SENSORS 2021; 7:10.5162/SMSI2021/PT7. [PMID: 38711829 PMCID: PMC11071017 DOI: 10.5162/smsi2021/pt7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2024]
Abstract
The NIST on a Chip (NOAC) program's central idea is the idea that measurement technology can be developed to enable metrology to be performed "outside the National Metrology Institute" by the creation of deployed and often miniaturized standards. These standards, when based on fundamental properties of nature, are directly tracible to the international system of units known as the SI. NIST is also developing quantum-based standards for SI traceability known as QSI, or Quantum based International System of units. Specifically, this paper will cover NIST efforts in the area of thermodynamic metrology to develop NOAC standards for pressure, vacuum and temperature measurements.
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Affiliation(s)
- J Hendricks
- National Institute of Standards and Technology, Physical Measurement Laboratory, 1Sensor Science Division, Thermodynamic Metrology Group, 100 Bureau Drive, Gaithersburg, MD 20899-8363
| | - Z Ahmed
- National Institute of Standards and Technology, Physical Measurement Laboratory, 1Sensor Science Division, Thermodynamic Metrology Group, 100 Bureau Drive, Gaithersburg, MD 20899-8363
| | - D Barker
- National Institute of Standards and Technology, Physical Measurement Laboratory, 1Sensor Science Division, Thermodynamic Metrology Group, 100 Bureau Drive, Gaithersburg, MD 20899-8363
| | - K Douglass
- National Institute of Standards and Technology, Physical Measurement Laboratory, 1Sensor Science Division, Thermodynamic Metrology Group, 100 Bureau Drive, Gaithersburg, MD 20899-8363
| | - S Eckel
- National Institute of Standards and Technology, Physical Measurement Laboratory, 1Sensor Science Division, Thermodynamic Metrology Group, 100 Bureau Drive, Gaithersburg, MD 20899-8363
| | - J Fedchak
- National Institute of Standards and Technology, Physical Measurement Laboratory, 1Sensor Science Division, Thermodynamic Metrology Group, 100 Bureau Drive, Gaithersburg, MD 20899-8363
| | - N Klimov
- National Institute of Standards and Technology, Physical Measurement Laboratory, 1Sensor Science Division, Thermodynamic Metrology Group, 100 Bureau Drive, Gaithersburg, MD 20899-8363
| | - J Ricker
- National Institute of Standards and Technology, Physical Measurement Laboratory, 1Sensor Science Division, Thermodynamic Metrology Group, 100 Bureau Drive, Gaithersburg, MD 20899-8363
| | - J Scherschligt
- National Institute of Standards and Technology, Physical Measurement Laboratory, 1Sensor Science Division, Thermodynamic Metrology Group, 100 Bureau Drive, Gaithersburg, MD 20899-8363
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8
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Makrides C, Barker DS, Fedchak JA, Scherschligt J, Eckel S, Tiesinga E. Collisions of room-temperature helium with ultracold lithium and the van der Waals bound state of HeLi. PHYSICAL REVIEW. A 2020; 101:10.1103/PhysRevA.101.012702. [PMID: 33283081 PMCID: PMC7713563 DOI: 10.1103/physreva.101.012702] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
We have computed the thermally averaged total, elastic rate coefficient for the collision of a room-temperature helium atom with an ultracold lithium atom. This rate coefficient has been computed as part of the characterization of a cold-atom vacuum sensor based on laser-cooled 6Li or 7Li atoms that will operate in the ultrahigh-vacuum (p < 10-6 Pa) and extreme-high-vacuum (p < 10-10 Pa) regimes. The analysis involves computing the X 2 Σ+ HeLi Born-Oppenheimer potential followed by the numerical solution of the relevant radial Schrodinger equation. The potential is computed using a single-reference-coupled-cluster electronic-structure method with basis sets of different completeness in order to characterize our uncertainty budget. We predict that the rate coefficient for a 300 K helium gas and a 1 μK Li gas is 1.467(13) × 10-9 cm3/s for 4He + 6Li and 1.471(13) × 10-9 cm3/s for 4He + 7Li, where the numbers in parentheses are the one-standard-deviation uncertainties in the last two significant digits. We quantify the temperature dependence as well. Finally, we evaluate the s-wave scattering length and binding of the single van der Waals bound state of HeLi. We predict that this weakly bound level has a binding energy of -0.0064(43) × hc cm-1 and -0.0122(67) × hc cm-1 for 4He6Li and 4He7Li, respectively. The calculated binding energy of 4He7Li is consistent with the sole experimental determination.
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Affiliation(s)
- Constantinos Makrides
- Joint Quantum Institute, College Park, Maryland 20742, USA, and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - Daniel S Barker
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - James A Fedchak
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Julia Scherschligt
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Stephen Eckel
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Eite Tiesinga
- Joint Quantum Institute, College Park, Maryland 20742, USA; Joint Center for Quantum Information and Computer Science, College Park, Maryland 20742, USA; and National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
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9
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Hankin AM, Clements ER, Huang Y, Brewer SM, Chen JS, Chou CW, Hume DB, Leibrandt DR. Systematic uncertainty due to background-gas collisions in trapped-ion optical clocks. PHYSICAL REVIEW. A 2019; 100:10.1103/physreva.100.033419. [PMID: 36452133 PMCID: PMC9706596 DOI: 10.1103/physreva.100.033419] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
We describe a framework for calculating the frequency shift and uncertainty of trapped-ion optical atomic clocks caused by background-gas collisions, and apply this framework to an 27Al+ clock to enable a total fractional systematic uncertainty below 10-18. For this clock, with 38(19) nPa of room-temperature H2 background gas, we find that collisional heating generates a non-thermal distribution of motional states with a mean time-dilation shift of order 10-16 at the end of a 150 ms probe, which is not detected by sideband thermometry energy measurements. However, the contribution of collisional heating to the spectroscopy signal is highly suppressed and we calculate the BGC shift to be -0.6(2.4) × 10-19, where the shift is due to collisional heating time dilation and the uncertainty is dominated by the worst case ±π/2 bound used for collisional phase shift of the 27Al+ superposition state. We experimentally validate the framework and determine the background-gas pressure in situ using measurements of the rate of collisions that cause reordering of mixed-species ion pairs.
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Affiliation(s)
- A. M. Hankin
- Time and Frequency Division, National Institute of Standards and Technology, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - E. R. Clements
- Time and Frequency Division, National Institute of Standards and Technology, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - Y. Huang
- Wuhan Institute of Physics and Mathematics, Chinese Academy of Sciences, Wuhan 430071, China
| | - S. M. Brewer
- Time and Frequency Division, National Institute of Standards and Technology, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - J.-S. Chen
- Time and Frequency Division, National Institute of Standards and Technology, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
| | - C. W. Chou
- Time and Frequency Division, National Institute of Standards and Technology, Boulder, Colorado 80305, USA
| | - D. B. Hume
- Time and Frequency Division, National Institute of Standards and Technology, Boulder, Colorado 80305, USA
| | - D. R. Leibrandt
- Time and Frequency Division, National Institute of Standards and Technology, Boulder, Colorado 80305, USA
- Department of Physics, University of Colorado, Boulder, Colorado 80309, USA
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10
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Makrides C, Barker DS, Fedchak JA, Scherschligt J, Eckel S, Tiesinga E. Elastic rate coefficients for Li+H 2 collisions in the calibration of a cold-atom vacuum standard. PHYSICAL REVIEW. A 2019; 99:https://doi.org/10.1103/PhysRevA.99.042704. [PMID: 33033788 PMCID: PMC7540224] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Ongoing efforts at the National Institute of Standards and Technology in creating a cold-atom vacuum standard device have prompted theoretical investigations of atom-molecule collision processes that characterize its operation. Such a device will operate as a primary standard for the ultrahigh-vacuum and extreme-high-vacuum regimes. This device operates by relating loss of ultracold lithium atoms from a conservative trap by collisions with ambient atoms and molecules to the background density and thus pressure through the ideal gas law. The predominant background constituent in these environments is molecular hydrogen H2. We compute the relevant Li+H2 Born-Oppenheimer potential energy surface, paying special attention to its uncertainty. Coupled-channel calculations are then used to obtain total rate coefficients, which include momentum-changing elastic and inelastic processes. We find that inelastic rotational quenching of H2 is negligible near room temperature. For a (T = 300)-K gas of H2 and 1.0-μK gas of Li atoms prepared in a single hyperfine state, the total rate coefficients are 6.0(1) × 10-9 cm3/s for both 6Li and 7Li isotopes, where the number in parentheses corresponds to a one-standard-deviation combined statistical and systematic uncertainty. We find that a 10-K increase in the H2 temperature leads to a 1.9% increase in the rate coefficients for both isotopes. For Li temperatures up to 100 μK, changes are negligible. Finally, a semiclassical Born approximation significantly overestimates the rate coefficients. The difference is at least ten times the uncertainty of the coupled-channel result.
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Affiliation(s)
- Constantinos Makrides
- Joint Quantum Institute, College Park, Maryland 20742, USA and Department of Physics, University of Maryland, College Park, Maryland 20742, USA
| | - Daniel S Barker
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - James A Fedchak
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Julia Scherschligt
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Stephen Eckel
- National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
| | - Eite Tiesinga
- Joint Quantum Institute, College Park, Maryland 20742, USA; Joint Center for Quantum Information and Computer Science, College Park, Maryland 20742, USA; and National Institute of Standards and Technology, Gaithersburg, Maryland 20899, USA
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11
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Barker DS, Norrgard EB, Klimov NN, Fedchak JA, Scherschligt J, Eckel S. Single-beam Zeeman slower and magneto-optical trap using a nanofabricated grating. PHYSICAL REVIEW APPLIED 2019; 11:77. [PMID: 33299903 DOI: 10.1038/s42005-019-0181-1] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/21/2019] [Accepted: 06/07/2019] [Indexed: 05/22/2023]
Abstract
We demonstrate a compact (0.25 L) system for laser cooling and trapping atoms from a heated dispenser source. Our system uses a nanofabricated diffraction grating to generate a magnetooptical trap (MOT) using a single input laser beam. An aperture in the grating allows atoms from the dispenser to be loaded from behind the chip, increasing the interaction distance of atoms with the cooling light. To take full advantage of this increased distance, we extend the magnetic field gradient of the MOT to create a Zeeman slower. The MOT traps approximately 106 7Li atoms emitted from an effusive source with loading rates greater than 106 s-1. Our design is portable to a variety of atomic and molecular species and could be a principal component of miniaturized cold-atom-based technologies.
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Affiliation(s)
- D S Barker
- Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - E B Norrgard
- Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - N N Klimov
- Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - J A Fedchak
- Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - J Scherschligt
- Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - S Eckel
- Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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12
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Barker DS, Norrgard EB, Klimov NN, Fedchak JA, Scherschligt J, Eckel S. Single-beam Zeeman slower and magneto-optical trap using a nanofabricated grating. PHYSICAL REVIEW APPLIED 2019; 11:10.1103/physrevapplied.11.064023. [PMID: 33299903 PMCID: PMC7722475 DOI: 10.1103/physrevapplied.11.064023] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
We demonstrate a compact (0.25 L) system for laser cooling and trapping atoms from a heated dispenser source. Our system uses a nanofabricated diffraction grating to generate a magnetooptical trap (MOT) using a single input laser beam. An aperture in the grating allows atoms from the dispenser to be loaded from behind the chip, increasing the interaction distance of atoms with the cooling light. To take full advantage of this increased distance, we extend the magnetic field gradient of the MOT to create a Zeeman slower. The MOT traps approximately 106 7Li atoms emitted from an effusive source with loading rates greater than 106 s-1. Our design is portable to a variety of atomic and molecular species and could be a principal component of miniaturized cold-atom-based technologies.
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13
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Barker DS, Norrgard EB, Scherschligt J, Fedchak JA, Eckel S. Light-induced atomic desorption of lithium. PHYSICAL REVIEW. A 2018; 98:043412. [PMID: 30984896 PMCID: PMC6460927 DOI: 10.1103/physreva.98.043412] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We demonstrate loading of a Li magneto-optical trap using light-induced atomic desorption. The magnetooptical trap confines up to approximately 4 × 104 7Li atoms with loading rates up to approximately 4 × 103 atoms per second. We study the Li desorption rate as a function of the desorption wavelength and power. The extracted wavelength threshold for desorption of Li from fused silica is approximately 470 nm. In addition to desorption of lithium, we observe light-induced desorption of background gas molecules. The vacuum pressure increase due to the desorbed background molecules is ≲ 50 % and the vacuum pressure decreases back to its base value with characteristic timescales on the order of seconds when we extinguish the desorption light. By examining both the loading and decay curves of the magneto-optical trap, we are able to disentangle the trap decay rates due to background gases and desorbed lithium. Our results show that light-induced atomic desorption can be a viable Li vapor source for compact devices and sensors.
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Affiliation(s)
- D S Barker
- Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - E B Norrgard
- Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - J Scherschligt
- Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - J A Fedchak
- Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - S Eckel
- Sensor Science Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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14
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Norrgard EB, Barker DS, Fedchak JA, Klimov N, Scherschligt J, Eckel S. Note: A 3D-printed alkali metal dispenser. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2018; 89:056101. [PMID: 29864797 PMCID: PMC6350244 DOI: 10.1063/1.5023906] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We demonstrate and characterize a source of Li atoms made from direct metal laser sintered titanium. The source's outgassing rate is measured to be 5(2) × 10-7 Pa L s-1 at a temperature T = 330 °C, which optimizes the number of atoms loaded into a magneto-optical trap. The source loads ≈1077Li atoms in the trap in ≈1 s. The loaded source weighs 700 mg and is suitable for a number of deployable sensors based on cold atoms.
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Affiliation(s)
- E. B. Norrgard
- Joint Quantum Institute, National Institute of Standards and Technology and University of Maryland, Gaithersburg, Maryland 20899, USA
| | - D. S. Barker
- Sensor Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - J. A. Fedchak
- Sensor Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - N. Klimov
- Sensor Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - J. Scherschligt
- Sensor Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - S. Eckel
- Sensor Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
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15
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Scherschligt J, Fedchak JA, Ahmed Z, Barker DS, Douglass K, Eckel S, Hanson E, Hendricks J, Klimov N, Purdy T, Ricker J, Singh R, Stone J. Quantum-based vacuum metrology at NIST. JOURNAL OF VACUUM SCIENCE & TECHNOLOGY. A, VACUUM, SURFACES, AND FILMS : AN OFFICIAL JOURNAL OF THE AMERICAN VACUUM SOCIETY 2018; 36:10.1116/1.5033568. [PMID: 38496305 PMCID: PMC10941226 DOI: 10.1116/1.5033568] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/19/2024]
Abstract
The measurement science in realizing and disseminating the unit for pressure in the International System of Units (SI), the pascal (Pa), has been the subject of much interest at NIST. Modern optical-based techniques for pascal metrology have been investigated, including multi-photon ionization and cavity ringdown spectroscopy. Work is ongoing to recast the pascal in terms of quantum properties and fundamental constants and in so doing, make vacuum metrology consistent with the global trend toward quantum-based metrology. NIST has ongoing projects that interrogate the index of refraction of a gas using an optical cavity for low vacuum, and count background particles in high vacuum to extreme high vacuum using trapped laser-cooled atoms.
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Affiliation(s)
- Julia Scherschligt
- National Institute of Standards and Technology, 100 Bureau Dr. Gaithersburg, MD 20899
| | - James A. Fedchak
- National Institute of Standards and Technology, 100 Bureau Dr. Gaithersburg, MD 20899
| | - Zeeshan Ahmed
- National Institute of Standards and Technology, 100 Bureau Dr. Gaithersburg, MD 20899
| | - Daniel S. Barker
- National Institute of Standards and Technology, 100 Bureau Dr. Gaithersburg, MD 20899
| | - Kevin Douglass
- National Institute of Standards and Technology, 100 Bureau Dr. Gaithersburg, MD 20899
| | - Stephen Eckel
- National Institute of Standards and Technology, 100 Bureau Dr. Gaithersburg, MD 20899
| | - Edward Hanson
- National Institute of Standards and Technology, 100 Bureau Dr. Gaithersburg, MD 20899
| | - Jay Hendricks
- National Institute of Standards and Technology, 100 Bureau Dr. Gaithersburg, MD 20899
| | - Nikolai Klimov
- National Institute of Standards and Technology, 100 Bureau Dr. Gaithersburg, MD 20899
| | - Thomas Purdy
- National Institute of Standards and Technology, 100 Bureau Dr. Gaithersburg, MD 20899
| | - Jacob Ricker
- National Institute of Standards and Technology, 100 Bureau Dr. Gaithersburg, MD 20899
| | - Robinjeet Singh
- National Institute of Standards and Technology, 100 Bureau Dr. Gaithersburg, MD 20899
| | - Jack Stone
- National Institute of Standards and Technology, 100 Bureau Dr. Gaithersburg, MD 20899
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16
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Fedchak JA, Abbott PJ, Hendricks JH, Arnold PC, Peacock NT. Recommended practice for calibrating vacuum gauges of the ionization type. JOURNAL OF VACUUM SCIENCE & TECHNOLOGY. A, VACUUM, SURFACES, AND FILMS : AN OFFICIAL JOURNAL OF THE AMERICAN VACUUM SOCIETY 2018; 36:10.1116/1.5025060. [PMID: 31092970 PMCID: PMC6513016 DOI: 10.1116/1.5025060] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/09/2023]
Abstract
This article represents a recommended practice for the calibration of ionization gauges using the comparison method. In this method, ionization gauges are compared to a working standard that has an SI traceable calibration. The ionization gauge is either of the hot-cathode ionization type or the cold-cathode ionization type. Details of the calibration apparatus, the principle of operation of the gauges, data analysis, uncertainty budget, and reporting the uncertainty are given.
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Affiliation(s)
| | - Patrick J. Abbott
- National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899
| | - Jay H. Hendricks
- National Institute of Standards and Technology (NIST), Gaithersburg, MD 20899
| | - Paul C. Arnold
- MKS Instruments, 6450 Dry Creek Parkway, Longmont, CO 80503
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17
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Eckel S, Barker DS, Fedchak JA, Klimov NN, Norrgard E, Scherschligt J, Makrides C, Tiesinga E. Challenges to miniaturizing cold atom technology for deployable vacuum metrology. METROLOGIA 2018; 55:10.1088/1681-7575/aadbe4. [PMID: 30983635 PMCID: PMC6459404 DOI: 10.1088/1681-7575/aadbe4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Cold atoms are excellent metrological tools; they currently realize SI time and, soon, SI pressure in the ultra-high (UHV) and extreme high vacuum (XHV) regimes. The development of primary, vacuum metrology based on cold atoms currently falls under the purview of national metrology institutes. Under the emerging paradigm of the "quantum-SI", these technologies become deployable (relatively easy-to-use sensors that integrate with other vacuum chambers), providing a primary realization of the pascal in the UHV and XHV for the end-user. Here, we discuss the challenges that this goal presents. We investigate, for two different modes of operation, the expected corrections to the ideal cold-atom vacuum gauge and estimate the associated uncertainties. Finally, we discuss the appropriate choice of sensor atom, the light Li atom rather than the heavier Rb.
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Affiliation(s)
- Stephen Eckel
- Sensor Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Daniel S Barker
- Sensor Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - James A Fedchak
- Sensor Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Nikolai N Klimov
- Sensor Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Eric Norrgard
- Sensor Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Julia Scherschligt
- Sensor Sciences Division, National Institute of Standards and Technology, Gaithersburg, MD 20899, USA
| | - Constantinos Makrides
- Joint Quantum Institute, National Institute of Standards and Technology and University of Maryland, Gaithersburg, MD 20899, USA
| | - Eite Tiesinga
- Joint Quantum Institute, National Institute of Standards and Technology and University of Maryland, Gaithersburg, MD 20899, USA
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