Improvement of the detection efficiency of channel plate electron multiplier for atom probe application

Déconihout, B.; Gerard, P.; Bouet, Mathieu; Bostel, A.

doi:10.1016/0169-4332(95)00405-x

Cited by 36 publications

(15 citation statements)

References 8 publications

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“…It is interesting to note that the results of Deconihout et al on the variation of efficiency with grid voltage [4] differ from those reported here and by Funsten et al [5] in two respects: the voltage required to achieve maximum eficiency and the efficiency decrease at high voltages. Deconihout et al required 50V before reaching peak efficiency, whereas we find a voltage of 5V is sufficient, and Funsten et al suggest an even lower voltage.…”

Section: Discussioncontrasting

confidence: 55%

“…If the open area ratio of the detector is taken to be 65%, then the use of a biassed grid has increased this detection efficiency to 81%, which is a significant improvement. This is less then the maximum detection efficiency quoted by Deconihout et al [4], though similar to that seen by Funsten et al [5]. Again, the higher saturation achieved by the curved-channel MCPs allows more of the secondary electrons to be detected, leading to a higher overall efficiency.…”

Section: Efficiency Characterisationmentioning

confidence: 38%

“…However, in their electrostatic modelling and electron trajectory calculations, they imposed a condition of an earthed equipotential at a very small distance (approximately 5 0~m ) above the front surface, which is equivalent to having a grid at this location. In order to quantify the improvement in detection efficiency which is obtained when using a biassed grid in an atom probe detector, Deconihout et al designed a detector which is only half covered by the grid, and which has separate anodes so that the detection rate from the two halves of the detector can be compared directly [4]. They observed an increase in the detection efficiency for grid bias voltages below SOV, up to a maximum (assuming an open area ratio of 60%) of almost 90%.…”

Section: Introductionmentioning

confidence: 99%

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Characterization of Efficiency Enhancement in Microchannel Plate Detectors

et al. 1996

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Abstract. The detection efficiency of a channel-plate detector is mainly determined by the open area ratio of its input face. which is typically 60%-70%. It is known that the efficiency can be enhanced by applying an electric field normal to the channel-plate surface, such that secondary electrons generated when ions strike the channel-plate surface are returned to the detector. This paper characterises the enhancement observed in channel-plate detectors for atom probe and 3-dimensional atom probe applications. In a double channel-plate detector, it was found that improvement in efficiency was approximately 30% as compared to the situation where all secondary events are lost. The secondary electron events are found to have a broader pulse height distribution, with a mean which is a factor of three lower than that of the primary ion events. Using the variation of efficiency with grid voltage, the maximum secondary electron energy was estimated to be IOeV. This value was used to calculate the loss in time and spatial resolution which would result from the detection of secondary electrons. These effects are shown to be acceptably small within a 3-dimensional atom probe detector design, for a wide range of bias voltages. Previous work has suggested that the efficiency gain from a biassed grid drops off at grid fields in the range 25-100V/mm. This effect is shown to have been generated by field fringing effects.

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Section: Discussioncontrasting

confidence: 55%

Section: Efficiency Characterisationmentioning

confidence: 38%

Section: Introductionmentioning

confidence: 99%

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Characterization of Efficiency Enhancement in Microchannel Plate Detectors

et al. 1996

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“…It is possible to increase the detection efficiency to over 72% by placing a biased mesh in front of the microchannel plates to drive secondary electrons into the plate. 164 This approach has the disadvantage, however, that a mesh shadow is superimposed on the data and overall background noise is increased.…”

Section: % Detection Efficiencymentioning

confidence: 99%

Atom probe tomography

Kelly¹,

Miller

2007

Review of Scientific Instruments

751

345

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The technique of atom probe tomography ͑APT͒ is reviewed with an emphasis on illustrating what is possible with the technique both now and in the future. APT delivers the highest spatial resolution ͑sub-0.3-nm͒ three-dimensional compositional information of any microscopy technique. Recently, APT has changed dramatically with new hardware configurations that greatly simplify the technique and improve the rate of data acquisition. In addition, new methods have been developed to fabricate suitable specimens from new classes of materials. Applications of APT have expanded from structural metals and alloys to thin multilayer films on planar substrates, dielectric films, semiconducting structures and devices, and ceramic materials. This trend toward a broader range of materials and applications is likely to continue.

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“…Efficiency is mostly limited by the open area of the microchannel plate part of the single-particle detector. This is a design limitation common to all atom-probes despite many efforts (Deconihout et al, 1996(Deconihout et al, , 2002, and has no existing practical instrumental solution.…”

Section: Introductionmentioning

confidence: 99%

Estimating the physical cluster‐size distribution within materials using atom‐probe

Stephenson

Moody

Gault

et al. 2010

Microscopy Res & Technique

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A limiting characteristic of the atom-probe technique is the nondetection of ions and this embodies a significant "missing information" problem in investigations of atomic clustering phenomena causing difficulty in the interpretation of any atom-probe experiment. It is shown that the measurable cluster-size distribution can be modeled by a mixed binomial distribution. A deconvolution method based upon expectation-maximization (EM) algorithm is presented to obtain the original physical distribution from an efficiency-degraded distribution, thereby providing means to calculate accurate cluster number densities from atom probe results. The accuracy of this restoration was predominantly dependent upon the detector efficiency and was proved to be highly accurate in the case of conventional atom-probe detector efficiencies (ε = 57%). Such considerations and measures are absolutely necessary when the number density of clusters and small precipitates is in any way regarded as important. We conclude that limitations in detector efficiency are more limiting for cluster-finding analyses via atom-probe techniques than spatial resolution issues, and therefore the current endeavors for improving detector technologies are well found.

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Improvement of the detection efficiency of channel plate electron multiplier for atom probe application

Cited by 36 publications

References 8 publications

Characterization of Efficiency Enhancement in Microchannel Plate Detectors

Characterization of Efficiency Enhancement in Microchannel Plate Detectors

Atom probe tomography

Estimating the physical cluster‐size distribution within materials using atom‐probe

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