摘要 :
Electrostatic particle-beam lenses using a concentric co-planar array of independently biased rings can be advantageous for some applications. Traditional electrostatic lenses often consist of axial series of biased rings, apertur...
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Electrostatic particle-beam lenses using a concentric co-planar array of independently biased rings can be advantageous for some applications. Traditional electrostatic lenses often consist of axial series of biased rings, apertures, or tubes. The science of lens design has devoted much attention to finding axial arrangements that compensate for the substantial optical aberrations of the individual elements. Thus, as with multi-element lenses for light, a multi-element charged-particle lens can have optical behavior that is far superior to that of the individual elements. This paper discusses the possibility that transverse multiple-concentric-ring lenses can achieve high performance, while also having advantages in terms of compactness and optical versatility.
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摘要 :
Electrostatic particle-beam lenses using a concentric co-planar array of independently biased rings can be advantageous for some applications. Traditional electrostatic lenses often consist of axial series of biased rings, apertur...
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Electrostatic particle-beam lenses using a concentric co-planar array of independently biased rings can be advantageous for some applications. Traditional electrostatic lenses often consist of axial series of biased rings, apertures, or tubes. The science of lens design has devoted much attention to finding axial arrangements that compensate for the substantial optical aberrations of the individual elements. Thus, as with multi-element lenses for light, a multi-element charged-particle lens can have optical behavior that is far superior to that of the individual elements. This paper discusses the possibility that transverse multiple-concentric-ring lenses can achieve high performance, while also having advantages in terms of compactness and optical versatility.
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摘要 :
The ion optics of an existing mass separator are documented. The elctrostatic and magnetic stages are analyzed theoretically, both separately and in combination, by paying particular attention to the ion trajectories, the linear a...
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The ion optics of an existing mass separator are documented. The elctrostatic and magnetic stages are analyzed theoretically, both separately and in combination, by paying particular attention to the ion trajectories, the linear and angular magnifications, and the dispersion. The possibility of converting the magnet into a tunable unit by means of current-carrying elements in the gap is demonstrated. The feasibility of correction coils constructed from printed circuit board is shown. (ERA citation 06:031132)
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A correction element for correction of the spherical aberration of rotationally symmetric electron lenses is described. It consists of circular annular diaphragms which block off those zone of the image-side wave front from which ...
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A correction element for correction of the spherical aberration of rotationally symmetric electron lenses is described. It consists of circular annular diaphragms which block off those zone of the image-side wave front from which elementary waves arrive at the image point in phase opposition. (ERA citation 04:024423)
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SIMION is a Fortran program that helps design electrostatic lenses. Both equipotential and ion path plots can be obtained. The program has proven extremely useful in numerous applications, ranging from mass spectrometer ion source...
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SIMION is a Fortran program that helps design electrostatic lenses. Both equipotential and ion path plots can be obtained. The program has proven extremely useful in numerous applications, ranging from mass spectrometer ion sources to setting up primary beam optics for organic SIMS. This report is a tutorial on its use, leading the user step-by-step through the various options. Examples are given, and a sample lens is analyzed and refined. Anyone with an interest in design of ion optics will benefit from acquiring and applying SIMION, either in its Fortran or its IBM-PC form. It is the former that is described here. (ERA citation 12:035946)
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A versatile precision beam transport channel was built with inexpensive parts requiring minimum precision machining. The critical items, an optical bench and sliding bases are commercially available standard items. The only import...
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A versatile precision beam transport channel was built with inexpensive parts requiring minimum precision machining. The critical items, an optical bench and sliding bases are commercially available standard items. The only important precision machining is illustrated, where a small section of an optical bench is used as a quadrupole assembly holding fixture. With this type of fixturing there is no loss of precision during the transfer of the quadrupole assembly from the EDM setup onto the final assembly, other than the manufacturer-specified mounting and dismounting tolerance. Displacement measurements of the pole tips taken on ten different quadrupole assemblies determined that RMS displacement in the x direction was .000307 and in the y direction was .000290. The actual performance of this system will be presented in other papers at this conference by A.W. Maschke and E.F. Meier. (ERA citation 08:027168)
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An ion-optical bench has been designed and constructed to obtain experimental data on the focusing properties of ion lenses in three dimensions. The heart of the apparatus is a position-sensitive detector (PSD) that gives output s...
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An ion-optical bench has been designed and constructed to obtain experimental data on the focusing properties of ion lenses in three dimensions. The heart of the apparatus is a position-sensitive detector (PSD) that gives output signals proportional to the x and y positions of each ion impact. The position signals can be displayed on an oscilloscope screen and analyzed by a two-parameter pulse-height analyzer, thereby giving a visual picture of the ion beam cross section and intensity distribution. The PSD itself is mounted on a track and is movable during operation from a position immediately following the ion lens to 30 cm away. This enables the rapid collection of accurate data on the intensity distribution and divergence angles of ions leaving the source lens. Examples of ion lens measurements are given. 5 refs., 5 figs. (ERA citation 13:049388)
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摘要 :
The Pierce design acceleration column has been widely used to accelerate high current beams. It operates well in the space charge limited condition, and will produce beams with a temperature comparable with that of the source. It ...
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The Pierce design acceleration column has been widely used to accelerate high current beams. It operates well in the space charge limited condition, and will produce beams with a temperature comparable with that of the source. It is restricted in current density, however, by the Child-Langmuir relation. If the ion source itself is not the limiting constraint, then the achievable current density is limited by the electric field at which sparking occurs. One sees clearly that the achievable current density decreases as one goes to higher voltages. This can be easily overcome by using electrostatic quadrupole focusing in the acceleration column. Now it can be shown that the space charge limited current density in a constant energy quadrupole transport channel is greater than that if one assumes that the electric fields on the quadrupoles can be as high in the ion source extraction electric fields. In practice, this is a conservative assumption. It follows that if the beam can be transported a large distance at the C-L current density limit, it can surely be accelerated as it goes from quadrupole to quadrupole. Hence, the necessity of having a high gradient acceleration column goes away. (ERA citation 09:017123)
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摘要 :
The Pierce design acceleration column has been widely used to accelerate high current beams. It operates well in the space charge limited condition, and will produce beams with a temperature comparable with that of the source. It ...
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The Pierce design acceleration column has been widely used to accelerate high current beams. It operates well in the space charge limited condition, and will produce beams with a temperature comparable with that of the source. It is restricted in current density, however, by the Child-Langmuir relation. If the ion source itself is not the limiting constraint, then the achievable current density is limited by the electric field at which sparking occurs. One sees clearly that the achievable current density decreases as one goes to higher voltages. This can be easily overcome by using electrostatic quadrupole focusing in the acceleration column. Now it can be shown that the space charge limited current density in a constant energy quadrupole transport channel is greater than that if one assumes that the electric fields on the quadrupoles can be as high in the ion source extraction electric fields. In practice, this is a conservative assumption. It follows that if the beam can be transported a large distance at the C-L current density limit, it can surely be accelerated as it goes from quadrupole to quadrupole. Hence, the necessity of having a high gradient acceleration column goes away. (ERA citation 09:017123)
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摘要 :
Results of experimental trials of the Gabor lens for several lenses are presented. Focal lengths are reported for proton and xenon beams from 300 to 750 keV. (ERA citation 04:024353)
