Positioning device for analytical instruments in a vacuum chamber

Abstract

A positioning device for an analytical instrument (e.g., an atom probe microscope or other nanoscale microscope) includes a primary carriage translatable relative to a vacuum chamber wall, and a secondary carriage connected to the primary carriage by a plurality of spaced actuators that allow the secondary carriage to translate and / or tilt relative to the primary carriage. An arm then extends from the secondary carriage through the vacuum chamber wall and connects to the instrument. The instrument may be rapidly extended or retracted within the vacuum chamber via its connection to the primary carriage, and may be more finely translated and / or tilted via its connection to the secondary carriage. A damping arrangement isolates the instrument from vibrations.

Description

Technical Field

[0001] This document generally relates to an invention of a positioning device for an analytical instrument in a vacuum chamber, and more specifically, to a positioning device that enables an analytical instrument to be properly positioned in a vacuum chamber with respect to a sample to be analyzed.

Background Art

[0002] Many analytical instruments for performing nanoscale analysis of material samples, such as transmission electron microscopes (TEMs), scanning transmission electron microscopes (STEMs), atomic force microscopes (AFMs), scanning tunneling microscopes (STMs), and atom probe microscopes (APMs), require a high-vacuum state for operation. It is useful to have an arrangement that combines these instruments so that different types of analysis can be performed on a sample without the need to move the sample from instrument to instrument. This is because, in particular, the preparation for analysis (such as the need to pump the chamber to a high-vacuum or ultra-high-vacuum state) can be time-consuming. However, these instruments are not only bulky but also likely to be affected by the presence of other instruments, so it is difficult to accommodate two or more instruments within a vacuum chamber (which is usually small; as the chamber size increases, the preparation time and other operational problems tend to increase). As an example, an APM needs to be positioned very close to the sample to be analyzed, and its presence tends to interfere with measurements from other instruments due to its electromagnetic field and radiative heat dissipation. This problem may require the APM and other instruments to be exchanged with each other, and each to move towards the sample in turn when measurements are to be taken, and each to move away from the sample when the measurements are completed. This is difficult to achieve without increasing the size of the vacuum chamber, which leads to the aforementioned problems. Furthermore, the movement of the instruments is a problem in itself. Most instruments need to be positioned very precisely with respect to the sample, and it is difficult to devise an extend / retract arrangement that can accurately reposition the instrument back to its original position after it has been retracted and extended.

[0003] Most of the following descriptions focus on the use of APM as a typical analytical instrument, so a brief overview of the structure and operation of a typical APM is provided below. A typical APM includes a sample mount and an ion detector. During a typical analysis, the sample is located in the sample mount, and a positive charge (e.g., baseline voltage) is applied to the sample so that the electrostatic field near the top of the sample (the surface closest to the detector and facing the detector) is about 90% of the electrostatic field (generally about 5-50 volts per nanometer) required to spontaneously ionize the surface atoms. The detector is positioned at a distance from the top (tip) of the sample and is grounded or negatively charged. A local electrode may be positioned between the sample and the detector and has an aperture aligned between the sample and the detector. The local electrode can be grounded or negatively charged. (The local electrode is sometimes called a “drawout electrode.” Furthermore, since electrodes in APMs typically function as electrostatic lenses, the term “lens” is sometimes used instead of the term “electrode.”) Energy beam pulses (e.g., laser beam pulses, electron beam pulses, ion beam pulses, etc.), positive electrical pulses (above baseline voltage), and / or other energy pulses (e.g., RF pulses) are intermittently applied to the sample to increase the probability of ionization of surface atoms on the sample. Alternatively or additionally, negative voltage pulses can be applied to any local electrode in synchronization with the aforementioned energy pulses(s).

[0004] In some cases, a pulse causes the ionization of a single atom near the top of the sample. The ionized atom(s) separates or "evaporates" from the sample surface, passes through the opening in the local electrode (if present), and collides with the surface of the detector (usually a microchannel plate (MCP)). The elemental identification of the ionized atom can be determined by measuring its time of flight (TOF). Time of flight is the time between the pulse that releases the ion from the sample surface and the time it takes to collide with the detector. The velocity of the ion (and therefore its TOF) varies based on the mass-to-charge state ratio (m / n) of the ionized atom, with lighter ions and / or more charged ions taking less time to reach the detector. Since the TOF of an ion indicates the mass-to-charge ratio of the ion, which indicates elemental identification, TOF can be used to determine the composition of the ionized atom. Furthermore, since the APM functions as a "point projection microscope," the position of the ionized atom on the sample surface corresponds to the position of the atom's collision with the detector, making it possible to determine the original location of the ionized atom on the sample. Thus, as the sample evaporates, a three-dimensional map or image of the constituent atoms of the sample can be constructed. The image represented by the map is a point projection with atomic resolution and a magnification of over 1 million times, but since the map / image data can be analyzed in virtually any orientation, the image can be considered to have more tomographic properties. Further details on APM can be found, for example, in the following documents: U.S. Patents 5,440,124, 7,157,702, 7,652,269, 7,683,318, 7,884,323, 8,074,292, 8,153,968, 8,276,210, 8,513,597, 8,575,544, 8,670,608, and 10,614,995, as well as other patents and documents mentioned in the aforementioned documents. [Overview of the project]

[0005] The present invention (as defined by the claims set out at the end of this document) relates to an equipment positioning device that at least partially alleviates the aforementioned problems relating to the positioning and / or replacement of equipment. A basic understanding of some of the features of a preferred version of the present invention can be obtained by examining the following summary of the invention, with further details provided elsewhere in this document. To aid the reader's understanding, the following examination will refer to the accompanying drawings (which will be briefly examined in the “Brief Description of the Drawings” section that follows this summary section of this document).

[0006] Figures 1-5 show typical versions of instrument positioning devices that may appear when used to position a typical atom probe microscope (APM) within a vacuum chamber. While the vacuum chamber is largely removed from the drawings for clarity, in Figure 1 it is mounted to port 52 in a vacuum sub-chamber 50, and the walls of the vacuum chamber can be assumed to be located roughly within the boundary indicated by the imaginary line (dashed line) 10. The APM 100, more specifically its ion optics (local electrode 102, deceleration lens 104, and deceleration lens 106), is visible protruding through the vacuum sub-chamber port 52 (and thus into the vacuum chamber 10), and the positioning device 200 for the APM 100 is positioned behind the back wall 54 of the vacuum sub-chamber 50. The positioning device 200 can either extend the APM 100 through port 52 (and thus further into the vacuum chamber 10 for analysis of a sample inside it) or retract the APM 100 through port 52 (and thus further into the vacuum sub-chamber 50 for housing other instruments inside it when analyzing a sample). Figures 2-4 show the APM100 and positioning device 200 without the vacuum sub-chamber 50.

[0007] A typical positioning device 200 includes a main carriage 202. The main carriage 202 is displaceable relative to the port 52 (and thus the vacuum chamber wall 10) via a main actuator 204 (e.g., a pneumatic cylinder) on it. As is best seen in Figures 3-4, the main actuator 204 has a shaft 206 extending along the instrument axis (an axis directed through the instrument toward the sample mount in the vacuum chamber 10) for mounting to the back wall 54 of the vacuum sub-chamber. A secondary carriage 208 is then displaceable relative to the main carriage 202 via four secondary actuators 210 (e.g., servo motors) (located near the four corners of the (square) secondary carriage 208). The secondary actuators 210 have shafts 212 extending for mounting to the main carriage 202. Four elongated instrument support arms 214 extend from the secondary carriage 208 through the main carriage 202. The main carriage 202 has one or more openings (not shown) through which the equipment support arm 214 extends freely without interference. The equipment support arm 214 then extends through the back wall 54 of the subchamber. By a tight gasket (not shown) or similar means, the equipment support arm 214 can be displaced along its length through the back wall 54 without losing any (or substantially any) vacuum in the vacuum subchamber 50.

[0008] Next, the APM100 (or other instrument) is attached to the instrument support arm end 216 within the vacuum sub-chamber 50. Thus, when the main carriage 202 is displaced relative to the vacuum chamber wall 10, the secondary carriage 208 translates, thereby causing any instrument attached to the instrument support arm 214 within the vacuum chamber to translate. The main actuator 204 that drives the main carriage 202 preferably has a stroke / displacement sufficient to move the instrument to the sample analysis position within the vacuum chamber 10 and to retract the instrument from the vacuum chamber 10 so that the instrument does not interfere with the analysis from other instruments. Furthermore, when the secondary actuator 210 is displaced by an equal length, the secondary carriage 208 translates relative to the main carriage 202, thereby causing any instrument attached to the instrument support arm 214 to translate. However, when the secondary actuator 210 is displaced unevenly, the secondary carriage 208 tilts relative to the main carriage 202, thereby causing any instrument attached to the instrument support arm 214 to tilt. When the positioning device 200 is used with the APM100, it is not necessary to swivel the instrument support arm 214 to the sub-carriage 208 and / or the instrument. This is because the uneven displacement of the sub-actuator 210 is sufficient to tilt the instrument by about 1 degree (which is usually sufficient for the APM100). Thus, the main actuator 204 and the main carriage 202 perform coarse positioning of the instrument between the analysis position and the storage position, while the sub-actuator 210 and the sub-carriage 208 perform fine positioning of the instrument to the analysis position. The positioning device 200 provides highly repeatable positioning of the instrument, and has the advantage that, for example, it can be quickly withdrawn from the analysis position to the storage position and then extended back to the analysis position with little to no difference between the previous and subsequent analysis positions.

[0009] In the aforementioned arrangement, the sub-actuators 210 are preferably arranged equidistant from the equipment axis and arranged around an actuator path extending around the equipment axis, with each sub-actuator 210 spaced equally apart from adjacent sub-actuators 210 along the actuator path. Similarly, the equipment support arms 214 are preferably arranged equidistant from the equipment axis and arranged around an arm path extending around the equipment axis, with each sub-actuator 210 spaced equally apart from adjacent equipment support arms 214 along the arm path. This arrangement increases the predictability of the movement of the equipment support arms 214, thereby facilitating the control of equipment positioning. Furthermore, the outer circumference of the actuator path is preferably larger than the outer circumference of the arm path. This is because it increases the lever effect of the sub-actuators 210, allowing for greater equipment tilt with less effort from the sub-actuators 210.

[0010] The APM100 shown in the drawing offers acceptable ion mass resolution and position measurement, while being particularly compact in design. A local electrode 102 is located at the end of the APM100 closest to the sample, followed by a deceleration lens 104 (electrode) that tends to slow and spread the sample ions drawn out by the local electrode 102, and then an elongated conical accelerating electrode 106 that tends to direct the sample ions parallel onto the ion detector 108. The detector 108 is located within a vacuum sub-chamber 50, which effectively functions as an extension of the vacuum chamber 10. The vacuum sub-chamber 50 has the advantage of being able to be pumped to a higher vacuum than the vacuum in the vacuum chamber 10, which can help improve the performance of the detector 108.

[0011] The positioning device 200 preferably also includes dampers 250 as shown in Figures 4a and 4b. The dampers 250 help to isolate the APM100 (or other instrument) from vibrations as it moves to and from its analysis position. In Figures 4a and 4b, the dampers 250 are shown mounted on the wall of the vacuum subchamber 50 and extending into the vacuum subchamber 50. Each damper 250 includes a conduit 252 extending from the outer circumference of the vacuum subchamber 50 to a foldable bellows 254, which opens onto a cylinder 256 containing a piston 258 sandwiched between viscoelastic members 260. An elongated damping member 262 then extends from the pivot end 264 of the damping member on the piston 258, through the bellows 254 and the conduit 252, projecting into the vacuum subchamber 50, where it terminates at the instrument end 266 of the damping member. When the vacuum subchamber 50 is at (or approaching) ambient pressure, the bellows 254 expands, and the instrument end 266 of the damping member is positioned at a distance from the instrument but directed toward it. However, when the vacuum subchamber 50 is evacuated, the ambient pressure compresses the bellows 254, pushing the damping member 262 into the vacuum subchamber 50. This continues until the instrument end 266 of the damping member is fitted into the instrument (here, in the socket 110 defined adjacent to the detector 108 in Figure 2). The bellows 254 and viscoelastic member 260 of each damper 250 elastically press the damping member 262 against the instrument, allowing the damping member 262 to pivot as the instrument is displaced in and out of the vacuum chamber 10 (more specifically, the vacuum subchamber 50), so that each damper 250 allows the instrument to move between the housing position and the analysis position while damping external vibrations that may be transmitted to the instrument. By placing opposing dampers 250 around the equipment (particularly as shown in Figure 4b), their forces cancel each other out, so that neither damper deflects the movement of the equipment away from the equipment axis.

[0012] The present invention is not limited to a typical positioning device and can be provided in various forms. More broadly, the present invention encompasses a positioning device having three or more elongated equipment support arms. Each equipment support arm extends through the wall of a vacuum chamber to its end within the vacuum chamber and is configured to translate along its length within the vacuum chamber wall. Uniform translational motion of the equipment support arm relative to the vacuum chamber wall causes any equipment attached to the end of the equipment support arm within the vacuum chamber to translate, while uneven translational motion of the equipment support arm relative to the vacuum chamber wall causes any equipment attached to the end of the equipment support arm within the vacuum chamber to tilt.

[0013] The present invention also includes a positioning device comprising: a secondary carriage configured to be displaceable relative to the wall of a vacuum chamber; and an elongated equipment support arm, which is rigidly attached to the secondary carriage and is displaceable along its length within the vacuum chamber wall, with equipment mounted thereto within the vacuum chamber. Uniform displacement of the equipment support arm relative to the vacuum chamber wall causes any equipment mounted on the end of the equipment support arm within the vacuum chamber to be displaced, while uneven displacement of the equipment support arm relative to the vacuum chamber wall causes any equipment mounted on the end of the equipment support arm within the vacuum chamber to be tilted.

[0014] The present invention further includes a positioning device comprising: a main carriage displaceable with respect to the vacuum chamber wall; a secondary carriage having an equipment support arm extending from the secondary carriage and passing through the vacuum chamber wall; and secondary actuators, each of which displaces the secondary carriage relative to the main carriage. Displacement of the main carriage relative to the vacuum chamber wall causes displacement of the secondary carriage, thereby displacing any equipment attached to the equipment support arm within the vacuum chamber. Furthermore, uniform displacement of the secondary actuators causes displacement of the secondary carriage relative to the main carriage, thereby displacing any equipment attached to the equipment support arm within the vacuum chamber, while uneven displacement of the secondary actuators causes tilting of the secondary carriage relative to the main carriage, thereby tilting any equipment attached to the equipment support arm within the vacuum chamber.

[0015] Furthermore, one or more of the following features may be present in any of the versions of the present invention described above. (1) The positioning device may include a sub-carriage, each equipment support arm extending from the sub-carriage, and the sub-carriage having three or more sub-actuators, each sub-actuator configured to translate the sub-carriage relative to the vacuum chamber wall. The uniform translational motion of the sub-actuators causes the sub-carriage and the equipment support arms extending therefrom to translate relative to the vacuum chamber wall, thereby causing any equipment attached to the end of the equipment support arm within the vacuum chamber to translate, and the uneven translational motion of the sub-actuators causes the sub-carriage to tilt relative to the vacuum chamber, thereby causing the equipment support arms extending from the sub-carriage to translate unevenly, and causing any equipment attached to the end of the equipment support arm within the vacuum chamber to tilt. (2) The positioning device may include a main carriage capable of translational motion relative to the vacuum chamber wall, with each sub-actuator extending between the main carriage and the sub-carriage. The translational motion of the main carriage relative to the vacuum chamber wall causes the sub-carriage and the equipment support arms extending therefrom to translate, thereby causing any equipment attached to the ends of the equipment support arms within the vacuum chamber to translate. (3) The positioning device may include a main actuator (e.g., a pneumatic cylinder) configured to translate or otherwise displace the secondary carriage relative to the main carriage. The main actuator preferably has a wider range of motion than the secondary actuator. (4) The instrument support arm can be securely attached to the analytical instrument (preferably inside the vacuum chamber) and / or the auxiliary carriage. (5) The equipment support arm may extend from the secondary carriage through the main carriage. (6) Each sub-actuator may be positioned equidistant from the instrument axis extending through the sub-carriage and the vacuum chamber wall, or arranged around an actuator path extending around the instrument axis, with each sub-actuator positioned equidistant from adjacent sub-actuators along the actuator path. (7) Each equipment support arm is positioned at an equidistant distance from the equipment axis and may be arranged around an arm path extending around the equipment axis, with each sub-actuator positioned at an equal distance from adjacent equipment support arms along the arm path. The outer circumference of the actuator path may be larger than the outer circumference of the arm path. (8) A positioning device may be used to position the APM. A preferred APM includes an elongated conical electrode (preferably an ion accelerating electrode) positioned at a distance from the instrument support arm by an ion detector. This arrangement may further include a local electrode and an ion decelerating electrode, the ion decelerating electrode being positioned between the local electrode and the conical electrode. (9) When the positioning device is used to position an instrument including an ion detector (e.g., an APM), the positioning device and / or instrument may include a vacuum subchamber within the vacuum chamber. The vacuum subchamber is configured to provide a higher vacuum than the vacuum chamber. (10) The positioning device may include damping members, each extending between a pivoting end flexibly attached to the vacuum chamber wall and an equipment end adjacent to the equipment. These damping members may be configured such that the damping member is biased by the vacuum in the vacuum chamber and the equipment end of the damping member is fitted to the equipment. The equipment end of the damping member may be removably fitted to the equipment, for example, by fitting into a socket in the equipment.

[0016] Further potential advantages, features, and objectives of the present invention are evident from the remainder of this document in conjunction with the relevant drawings. [Brief explanation of the drawing]

[0017] [Figure 1] This figure shows a typical analytical instrument positioning device 200 used to position an atom probe microscope (APM) 100 within a vacuum chamber 10, with the APM's lenses 102, 104, and 106 protruding from a vacuum sub-chamber port 52, and the APM's ion detector (not shown) located within the vacuum sub-chamber 50. [Figure 2] Figure 1 shows the configuration with the vacuum sub-chamber 50 removed, thereby illustrating the APM's ion optical system (local electrode 102, deceleration lens 104, and deceleration lens 106) together with its ion detector 50. [Figure 3a] Figure 2 is a side view of the arrangement, showing the APM100 in a state where it is at least partially retracted. [Figure 3b] Figure 2 is a side view of the arrangement, showing that the APM100 is in an at least partially extended position. [Figure 4a] This is a top view of the arrangement shown in Figure 1. [Figure 4b]Figure 4a is a cross-sectional view along line AA, showing a typical damper 250 used to stabilize the APM100 during extension and retraction. [Modes for carrying out the invention]

[0018] Figure 1 shows a typical version of a positioning device 200 that may be used to position an atom probe microscope (APM) 100 within a vacuum chamber. In Figure 1, only the ion optics of the APM (its local electrode 102, deceleration lens 104, and deceleration lens 106) are visible, while the rest of the APM 100 (primarily its detector) is located within a vacuum sub-chamber 50 in an arrangement as described in U.S. Patent No. 1,614,995. The vacuum sub-chamber 50 has a port 52 configured to be mounted on the vacuum chamber 10 of another instrument (e.g., a transmission electron microscope (TEM)), thereby effectively defining a portion of the vacuum chamber 10. The local electrode 102, deceleration lens 104, and deceleration lens 106 of the APM are shown protruding from the vacuum sub-chamber 50 into the vacuum chamber. Within the vacuum sub-chamber 50, the APM 100 is mounted to the positioning device 200, in particular to the end of an instrument support arm 214 extending through the back wall 54 of the vacuum sub-chamber 50. Therefore, the APM100 can be moved by the positioning device 200 within the vacuum sub-chamber 50 (and within the vacuum chamber 10), thereby allowing its local electrode 102 to be positioned right next to the sample undergoing TEM analysis within the vacuum chamber 10.

[0019] Since the presence of the APM100 may interfere with the TEM imaging of the sample, the main actuator 204 is provided to quickly move the APM100 away from (and then towards) the sample. The main actuator 204 (e.g., a pneumatic cylinder) has its movement axis aligned with the instrument axis (i.e., the axis of the ion flight cone when the APM100 is in its default position). The main actuator 204 has one actuating part (e.g., its body / cylinder 207) attached to the main carriage 202 (shown in the shape of a substantially square plate) and another actuating part (e.g., a shaft / piston 206 that translates within the body / cylinder 207) attached to the back wall 54 of the vacuum sub-chamber. Thus, the operation of the main actuator 204 causes the main carriage 202 to translate towards or away from the back wall 54 of the vacuum sub-chamber, and thus towards or away from the vacuum sub-chamber 50 and the TEM vacuum chamber 10.

[0020] Similarly, each sub-actuator 210 has one actuating part (e.g., its body / cylinder 213) attached to the main carriage 202 and another actuating part (e.g., its shaft / piston 212) connected to the sub-carriage 208. The actuation of two adjacent sub-actuators 210 causes the sub-carriage 208 to tilt around a horizontal or vertical axis on the sub-carriage 208, while the actuation of two non-adjacent sub-actuators 210 (or all three sub-actuators 210) by different respective distances causes the sub-carriage 208 to tilt around both the horizontal and vertical axes. When the sub-actuators 210 are actuated by the same amount, the sub-carriage 208 translates along the machine axis. The secondary carriage 208 has an instrument support arm 214 located on the opposite side of the tilt axis of the secondary carriage 208 (for example, near the corner of the secondary carriage 208), which extends to the APM 100 (more specifically, the APM mount 112 adjacent to the detector of the APM) through one or more openings (not shown) in the back wall 54 of the vacuum subchamber. Thus, when the secondary carriage 208 tilts, the selected instrument support arm 214 extends into the back wall 54 of the vacuum subchamber or retracts out of the back wall 54, thereby tilting the APM 100 and deflecting its local electrode 102 (and the ion flight cone) from the instrument axis. Because the hermetically tight fitting of the instrument support arm 214 within the back wall 54 of the vacuum subchamber allows only a limited tilt of the APM 100, this deflection is small (but sufficient), and the ion flight cone axis tilts only about 1 degree from the instrument axis.

[0021] Thus, by the main actuator 204, the APM 100 can be rapidly translated over a greater distance towards or away from the sample (and the TEM within the vacuum chamber 10). By its operation, the main carriage 202 moves towards or away from the back wall 54 of the vacuum sub-chamber, thereby also transporting the sub-carriage 208 (connected to the main carriage 202 by the sub-actuator 210) and the APM 100 (connected to the sub-carriage 208 by the instrument support arm 214). The sub-actuator 210 can perform fine positioning by adjusting the sub-carriage 208 to translate and / or tilt the APM 100 with respect to the instrument axis. Preferably, in practice, after the APM 100 is positioned near the sample via the main actuator 204, the local electrode 102 of the APM is focused on the sample and APM measurement values can be obtained by using the sub-actuator 210. However, when acquiring TEM measurement values by the main actuator 204, the APM 100 rapidly retreats from the sample, and then, when the TEM measurement is completed, it can extend towards the sample with the local electrode 102 positioned at its original measurement position or very close thereto. This is of great value because the alignment of the local electrode 102 with the target area on the APM sample can be a time-consuming process.

[0022] The aforementioned configuration is enhanced by a damping system that helps reduce or eliminate vibrations in the APM100. Because the APM100 is supported in a cantilever configuration (via an instrument support arm 214 extending from the back wall 54 of the vacuum subchamber), it may be susceptible to vibrations from the environment (e.g., transmitted from the floor or other ambient conditions or audible noise) and / or vibrations from extension / retraction, such vibrations may interfere with TEM or other analysis. As seen in Figure 1, dampers 250 are provided on the vacuum subchamber 50, with further details shown in Figures 4a-4b. Each damper 250 includes a damping member 262. The damping member 262 has an instrument end 266 of the damping member that can be received in a concave damping receptacle (socket) 110 (seen in Figures 2 and 4b) in the APM mount 112, and an opposing swivel end 264 of the damping member having a thin piston 258. A thin piston 258 is sandwiched (or otherwise buffered) within the cylinder 256 by a viscoelastic member 260 (e.g., a Sorbothane disc). A vacuum-sealed bellows 254 connects the cylinder 256 to the vacuum subchamber 50. When the vacuum subchamber 50 is evacuated, atmospheric pressure compresses the bellows 254, pushing the damping member 262 into the vacuum subchamber 50. This continues until the instrument end 266 of the damping member engages with the damping receptacle 110 in the detector housing. As the linear actuator causes the APM 100 and its detector to translate and / or tilt, the flexible bellows 254 allows the first end of the connecting rod of the damper 250 to follow (and bias) the APM mount 112. The viscoelastic member 260, and to a certain extent the bellows 254, then effectively dampen the vibrations of the APM 100, and the damper 250 on the opposite side of the APM 100 resists the displacement of the APM 100 from the instrument axis as it moves translationally within the sub-chamber 50. At the same time, the damper 250 maintains the vacuum in the vacuum sub-chamber 50 and the chamber 10, generating little to no heat that could potentially interfere with TEM or APM analysis.

[0023] The APM100 (or at least most of them) is ideally positioned as far away from the sample as possible when retracted so as not to interfere with TEM measurements. Therefore, the ion optics of a typical APM100 are interesting because they increase the length of the ion flight path between the local electrode 102 and the detector 108, thereby positioning the detector 108 further away from the sample (and increasing the flight time, thus improving the mass resolution of the APM). This is achieved by following the local electrode 102, which has an ion-deceleration electrostatic lens that tends to increase the spreading of ions emitted from the sample, with an ion-accelerating electrode that directs the spread ions parallel onto the detector 108. Thus, for example, ions from a positively charged sample could be accelerated towards the local electrode 102 at ground potential, then decelerated through an opening in a negatively charged electrostatic lens 104, and then accelerated onto the detector by a positively charged conical accelerating electrode 106.

[0024] It should be understood that the versions of the present invention described above are merely typical, and the present invention is not intended to be limited to these versions. As an example, the translational motion and tilt of the secondary carriage 208 can be achieved by as few as three equipment support arms 214, or by more than four equipment support arms 214. However, the symmetrical arrangement provided by the four equipment support arms 214 shown tends to provide easier control. As another example, the secondary carriage 208 can achieve greater tilt if the equipment support arms 214 are swivelably mounted to the secondary carriage 208 and the equipment (or at least one of them), however, greater tilt is not necessary if the equipment is an APM, and swivel connections (e.g., by ball-and-socket universal joints) tend to introduce positioning uncertainty. As a final example, the arrangement described uses a pneumatic cylinder as the main actuator 204 and a DC servo motor as the secondary actuator 210, but different actuators can be used instead. The described configuration has the advantage that once fine positioning is complete, the secondary (servo motor) linear actuator 210 can be depowered, thereby avoiding further heat input that could interfere with TEM or other analyses. The pneumatic main actuator 204 can then be started and stopped as needed to extend and retract the APM100 while ensuring that heat input into the vacuum chamber is negligible.

[0025] The scope of the present invention is limited only by the claims set forth below, and the present invention encompasses all different versions that are literally or equivalently contained within these claims. Within these claims, elements thereof should not be construed as “means plus function” elements or “step plus function” elements in accordance with § 112(f) of the U.S. Patent Act unless the words “means for” or “step for” are expressly used in the particular element thereof.

Claims

1. A positioning device for analytical instruments in a vacuum chamber, wherein the positioning device includes three or more elongated instrument support arms, each instrument support arm is a. Extending through the wall of the vacuum chamber to the end of the equipment support arm inside the vacuum chamber, b. It is configured to move in translational motion along its length within the wall of the vacuum chamber, Therefore, A. Due to the uniform translational motion of the equipment support arm relative to the vacuum chamber wall, any equipment attached to the end of the equipment support arm within the vacuum chamber undergoes translational motion. B. A positioning device in which any equipment attached to the end of the equipment support arm is tilted within the vacuum chamber due to the uneven translational motion of the equipment support arm relative to the vacuum chamber wall.

2. It further includes a secondary carriage, a. Each equipment support arm extends from the sub-carriage, b. Having three or more sub-actuators, each sub-actuator configured to move the sub-carriage in translational motion relative to the vacuum chamber wall, Therefore, A. Due to the uniform translational motion of the sub-actuator, the sub-carriage and the equipment support arm extending therefrom move in translation relative to the vacuum chamber wall, thereby causing any equipment attached to the end of the equipment support arm to move in translation within the vacuum chamber. B. The positioning device according to claim 1, wherein the sub-carriage is tilted with respect to the vacuum chamber due to the uneven translational motion of the sub-actuator, thereby causing the equipment support arm extending from the sub-carriage to move unevenly, and any equipment attached to the end of the equipment support arm to tilt within the vacuum chamber.

3. The positioning device according to claim 2, wherein the equipment support arm is firmly attached to the sub-carriage.

4. a. Further comprising a main carriage capable of translational motion relative to the vacuum chamber wall, b. Each sub-actuator extends between the main carriage and the sub-carriage, and each sub-actuator is configured to displace the sub-carriage relative to the main carriage. The positioning device according to claim 2, wherein the translational motion of the main carriage with respect to the vacuum chamber wall causes the sub-carriage and the equipment support arm extending therefrom to perform translational motion, thereby causing any equipment attached to the end of the equipment support arm to perform translational motion within the vacuum chamber.

5. The positioning device according to claim 4, wherein the equipment support arm extends from the sub-carriage through the main carriage.

6. a. The sub-actuator is, (1) Displaced at an equal distance from the equipment axis extending through the sub-carriage and the vacuum chamber wall, (2) Arranged around an actuator path extending around the machine axis, each sub-actuator is positioned at equal intervals from its adjacent sub-actuators along the actuator path, b. The equipment support arm is, (1) Arranged at an equal distance from the equipment axis, (2) The positioning device according to claim 2, wherein each sub-actuator is arranged around an arm path extending around the equipment axis, and each sub-actuator is positioned at equal intervals from adjacent equipment support arms along the arm path.

7. The positioning device according to claim 6, wherein the outer circumference of the actuator path is larger than the outer circumference of the arm path.

8. The positioning device according to claim 1, further comprising equipment firmly attached to the end of the equipment support arm within the vacuum chamber.

9. The positioning device according to claim 8, wherein the device includes an atom probe ion detector.

10. a. The device includes an elongated conical electrode, b. The positioning device according to claim 9, wherein the ion detector is located between the conical electrode and the end of the equipment support arm.

11. a. The apparatus includes an electrode array, and the electrode array is (1) Local electrode and (2) Ion accelerating electrode, (3) Having an ion-deceleration electrostatic lens between the local electrode and the ion-accelerating electrode, b. The positioning device according to claim 9, wherein the ion detector is located between the electrode array and the end of the equipment support arm.

12. a. The apparatus includes a vacuum subchamber configured to provide a higher vacuum than the vacuum chamber, b. The positioning device according to claim 9, wherein the ion detector is located within the vacuum subchamber.

13. a. Equipment attached to the end of the equipment support arm within the vacuum chamber, b. A damping member, where each damping member is (1) The pivot end of the damping member which is flexibly attached to the vacuum chamber wall, (2) Further including a damping member extending between the equipment end of a damping member adjacent to the equipment, The positioning device according to claim 1, wherein the vacuum in the vacuum chamber extends to the damping member, and the equipment end of the damping member engages with the equipment.

14. a. Equipment attached to the end of the equipment support arm within the vacuum chamber, b. A damping member, where each damping member is (1) The pivot end of the damping member which is flexibly attached to the vacuum chamber wall, (2) Further including a damping member extending between the equipment end of a damping member adjacent to the equipment, The positioning device according to claim 1, wherein the vacuum in the vacuum chamber extends to the damping member, and the equipment end of the damping member engages with the equipment.

15. a. Equipment attached to the end of the equipment support arm within the vacuum chamber, b. A damping member, where each damping member is (1) The pivot end of the damping member which is flexibly attached to the vacuum chamber wall, (2) The positioning device according to claim 1, further comprising a damping member extending between the end of a damping member that fits into a socket in the device and the other end of the device.

16. a. Equipment attached to the end of the equipment support arm within the vacuum chamber, b. A damping member, where each damping member is (1) A pivot end of a damping member attached to an expandable member attached to the wall of the vacuum chamber, (2) The positioning device according to claim 1, further comprising a damping member extending between the end of a damping member configured to fit with the equipment and the equipment end of a damping member configured to fit with the equipment.

17. A positioning device for analytical instruments in a vacuum chamber, wherein the positioning device is a. A sub-carriage configured to be displaced relative to the wall of the vacuum chamber, b. A long, slender equipment support arm, (1) The sub-carriage is securely attached, (2) It is capable of translational motion along its length within the wall of the vacuum chamber, (3) Includes an elongated equipment support arm to which equipment is mounted within the vacuum chamber, Therefore, A. Due to the uniform translational motion of the equipment support arm relative to the vacuum chamber wall, any equipment attached to the end of the equipment support arm within the vacuum chamber undergoes translational motion. B. A positioning device in which any equipment attached to the end of the equipment support arm is tilted within the vacuum chamber due to the uneven translational motion of the equipment support arm relative to the vacuum chamber wall.

18. a. Main carriage and, b. A main actuator configured to displace the main carriage relative to the wall of the vacuum chamber, c. A sub-actuator installed between the main carriage and the sub-carriage, c. The positioning device according to claim 17, further comprising a main actuator configured to displace the sub-carriage relative to the main carriage.

19. A positioning device for analytical instruments in a vacuum chamber, wherein the positioning device is a. A main carriage that is displaceable relative to the vacuum chamber wall, b. A secondary carriage having an equipment support arm extending from the secondary carriage and passing through the vacuum chamber wall, c. A sub-actuator, each sub-actuator displacing the sub-carriage relative to the main carriage, including: Therefore, A. The displacement of the main carriage relative to the vacuum chamber wall causes the secondary carriage to be displaced, which in turn causes any equipment attached to the equipment support arm within the vacuum chamber to be displaced. B. Due to the uniform displacement of the sub-actuator, the sub-carriage is displaced relative to the main carriage, thereby displacing any equipment attached to the equipment support arm within the vacuum chamber. C. A positioning device in which the sub-carriage tilts relative to the main carriage due to the uneven displacement of the sub-actuator, thereby tilting any equipment attached to the equipment support arm within the vacuum chamber.

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