Design and experimental validation of a compact collimated Knudsen source

Wouters, S.H.W.; Haaf, G. ten; Mutsaers, P.H.A.; Vredenbregt, E.J.D.

doi:10.1063/1.4960997

Cited by 6 publications

(8 citation statements)

References 22 publications

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“…Figure 8 shows the beam density as a function of source temperature in two cases: with the magnetic field gradient set to the optimal value of 1.1 T/m and without any magnetic field. The figure also shows a scaling law that scales the first data point of both measurements with the flux coming from the Knudsen source [27]. Although the beam density does increase with increasing source temperature, figure 8 shows that the scaling law only holds for the lowest temperatures and in the case of no magnetic field gradient.…”

Section: E Beam Density Vs Source Temperaturementioning

confidence: 88%

“…Note that in the actual experiment the beam travels in the vertical direction since this will also be the orientation of the source when mounted on a FIB system. As shown, an atomic rubidium beam from a collimated Knudsen source [27] with temperature T s effuses into a two-dimensional magneto-optical trap (2D MOT) [30]. After the 2D MOT the atoms can be cooled to sub-Doppler temperature with a second set of counter propagating laser beams, forming an optical molasses.…”

Section: Methodsmentioning

confidence: 99%

“…Here, experimental results are presented of the atomic beam formation in the atomic beam laser-cooled ion source (ABLIS), in which a 2D MOT is directly loaded from a collimated Knudsen source [27] and used to create a high brightness 85 Rb atom beam. Extensive simulations of this source, which assume that all atoms in the beam can be transformed into ions and that includes the interaction of the ions after ionization, predict that when combined with a conventional electrostatic focusing column, 1 pA of 30 keV rubidium ions can be focused to a 1 nm spot [15,28].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Direct Magneto-Optical Compression of an Effusive Atomic Beam for Application in a High-Resolution Focused Ion Beam

et al. 2017

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An atomic rubidium beam formed in a 70-mm-long two-dimensional magneto-optical trap (2D MOT), directly loaded from a collimated Knudsen source, is analyzed using laser-induced fluorescence. The longitudinal velocity distribution, the transverse temperature, and the flux of the atomic beam are reported. The equivalent transverse reduced brightness of an ion beam with properties similar to the atomic beam is calculated because the beam is developed to be photoionized and applied in a focused ion beam. In a single two-dimensional magneto-optical trapping step, an equivalent transverse reduced brightness of ð1.0 þ0.8 −0.4 Þ × 10 6 A=ðm 2 sr eVÞ is achieved with a beam flux equivalent to ð0.6 þ0.3 −0.2 Þ nA. The temperature of the beam is further reduced with an optical molasses after the 2D MOT. This optical molasses increases the equivalent brightness to ð6 þ5 −2 Þ × 10 6 A=ðm 2 sr eVÞ. For currents below 10 pA, for which disorder-induced heating can be suppressed, this number is also a good estimate of the ion-beam brightness that can be expected. Such an ion-beam brightness would be a 6× improvement over the liquid-metal ion source and could improve the resolution in focused ion-beam nanofabrication.

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Section: E Beam Density Vs Source Temperaturementioning

confidence: 88%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Direct Magneto-Optical Compression of an Effusive Atomic Beam for Application in a High-Resolution Focused Ion Beam

et al. 2017

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“…Looking forward, combining Monte Carlo and master equation simulations allows the tracking of atom trajectories and their internal states simultaneously, which is indispensable for customizing the laser manipulation of atoms close to or within a chip-scale source itself [37]. The simple recipe phrased in linear algebra for reconstructing the speed/angular distribution of the atomic beams is important for precision spectroscopy [38] or atom scattering experiments [39], and useful for guiding collimator and oven designs [40][41][42]. where we've dropped all constants as coefficients and A(v, r, θ, φ, δ) represents A(v, r, θ, φ, δ, s 0 ) = sin θ • R sc (r, θ, φ, s 0 , δ, v) • v 2 e −(v/α) 2 .…”

Section: Discussionmentioning

confidence: 99%

Near source fluorescence spectroscopy for miniaturized thermal atomic beams

Li,

Wei,

Chai

et al. 2019

Preprint

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Miniature atomic beams can provide new functionalities for atom based sensing instruments such as atomic clocks and interferometers. We recently demonstrated a planar silicon device for generating well-collimated thermal atomic beams [1]. Here, we present a near-source fluorescence spectroscopy (NSFS) technique that can fully characterize such miniature beams even when measured only a few millimeters from the nozzle exit. We also present a recipe for predicting the fluorescence spectrum, and therefore, the source angular distribution, even under conditions of strong laser saturation of the probing transition. Monte Carlo simulations together with multi-level master equation calculations fully account for the influence of optical pumping and spatial extension of the Gaussian laser beam. A notable consequence of this work is the agreement between theory and experimental data that has allowed fine details of the angular distribution of the collimator to be resolved over 3 decades of dynamic range of atomic beam output flux.

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“…In this article the ionization strategy that is applied in the atomic beam laser cooled ion source (ABLIS) [7] is introduced. In the ABLIS setup a thermal beam of Rb atoms effuses from a collimated Knudsen source [8] and is laser cooled and compressed in the transverse direction. Subsequently the atoms are ionized in a two-step * e.j.d.vredenbregt@tue.nl photoionization process.…”

Section: Introductionmentioning

confidence: 99%

Cavity-enhanced photoionization of an ultracold rubidium beam for application in focused ion beams

et al. 2017

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A two-step photoionization strategy of an ultracold rubidium beam for application in a focused ion beam instrument is analyzed and implemented. In this strategy the atomic beam is partly selected with an aperture after which the transmitted atoms are ionized in the overlap of a tightly cylindrically focused excitation laser beam and an ionization laser beam whose power is enhanced in a build-up cavity. The advantage of this strategy, as compared to without the use of a build-up cavity, is that higher ionization degrees can be reached at higher currents. Optical Bloch equations including the photoionization process are used to calculate what ionization degree and ionization position distribution can be reached. Furthermore, the ionization strategy is tested on an ultracold beam of 85 Rb atoms. The beam current is measured as a function of the excitation and ionization laser beam intensity and the selection aperture size. Although details are different, the global trends of the measurements agree well with the calculation. With a selection aperture diameter of 52 µm, a current of (170 ± 4) pA is measured, which according to calculations is 63% of the current equivalent of the transmitted atomic flux. Taking into account the ionization degree the ion beam peak reduced brightness is estimated at 1 × 10 7 A/(m 2 sr eV).

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Design and experimental validation of a compact collimated Knudsen source

Cited by 6 publications

References 22 publications

Direct Magneto-Optical Compression of an Effusive Atomic Beam for Application in a High-Resolution Focused Ion Beam

Direct Magneto-Optical Compression of an Effusive Atomic Beam for Application in a High-Resolution Focused Ion Beam

Near source fluorescence spectroscopy for miniaturized thermal atomic beams

Cavity-enhanced photoionization of an ultracold rubidium beam for application in focused ion beams

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