WO2024153924A2

WO2024153924A2 - Interface apparatus for a particle beam instrument

Info

Publication number: WO2024153924A2
Application number: PCT/GB2024/050121
Authority: WO
Inventors: Chris TYRRELL; Santokh BHADARE; Paul EVETTS
Original assignee: Oxford Instruments Nanotechnology Tools Ltd
Current assignee: Oxford Instruments Nanotechnology Tools Ltd
Priority date: 2023-01-18
Filing date: 2024-01-17
Publication date: 2024-07-25
Anticipated expiration: 2025-07-18
Also published as: GB202300722D0; WO2024153924A3; CN120380566A; EP4652622A2

Abstract

An interface apparatus that facilitates rapid, easy, and safe exchanging and precise positioning of detectors and accessories for a particle beam instrument is described. The interface apparatus comprises: an alignment member for causing a detector module of the particle beam instrument to be mounted to the interface apparatus in a predefined orientation; and, a guide mechanism configured when in use to move the mounted detector module along a guide path between a first position, within a chamber of the particle beam instrument, and a second position external to the instrument. A method of replacing a detector module, and a method of replacing a sensor head of a detector module, in a particle beam instrument using the interface apparatus, are also described.

Description

INTERFACE APPARATUS FOR A PARTICLE BEAM INSTRUMENT

FIELD OF THE INVENTION

The present invention relates to an interface apparatus for a particle beam instrument and a method to facilitate replacing a detector module for a particle beam instrument more rapidly, precisely, and safely.

BACKGROUND

Particle beam instruments, such as electron beam microscopes, have the capability for multiple uses, each requiring different sensors or peripheral devices. Ports are designed into the electron beam microscope chamber to accommodate different detectors and instruments. Swapping detectors and instruments by disconnecting at the microscope port requires special training due to the risk of physical or electrostatic discharge (ESD) damage. Moreover, achieving realignment of an exchanged or reinserted sensor to the beam within the instrument is difficult, and so is a barrier to flexible use of the microscope. Swapping detectors and instruments is usually carried out by a service engineer, rather than by the user, owing to these issues.

In addition, in a scanning electron microscope for example, detectors placed under the final lens are at higher risk of damage due to collision with other peripheral devices (e.g. additional detectors, cold traps, gas injectors) in the vicinity during installation or removal and collision with the specimen or stage when the stage is being moved.

Conventionally, the procedure for repairing an electron beam microscope detector requires an engineer visit, and often a detector return to a factory ora local service site for repair. This leads to much longer downtimes during which the instrument is impaired or inoperable, and results in higher costs.

There exists a need for an arrangement that allows rapid, easy, and safe swapping of instrument detectors and accessories, for repair or alternative uses, and for an insertion mechanism capable of delivering any sensor to the correct analytical position when carrying out these procedures. In particular, there is a need for such an arrangement to provide these benefits while maintaining a good thermal heat path from the detector, minimising the risks of ESD and physical damage, and also maintaining good alignment between exchangeable sensor heads and the analytical position in the chamber.

SUMMARY OF INVENTION

In accordance with a first aspect of the invention there is provided an interface apparatus for a particle beam instrument, the interface apparatus comprising: an alignment member for causing a detector module of the particle beam instrument to be mounted to the interface apparatus in a first predefined orientation; and, a guide mechanism configured when in use to move the mounted detector module along a guide path between a first position at a predefined location within a chamber of the particle beam instrument, and a second position external to the instrument, such that the mounted detector module effects a second predefined orientation, with respect to the particle beam instrument, when at the first position.

The inventors have realised that the issues outlined above may be overcome by providing an interface apparatus that may offer a pre-aligned, pre-tested detector module, which is preferably also ESD-safe and user-exchangeable. The apparatus addresses the key challenge in the replacement of a detector module or sensor head, by a user, on-site, with lower risk of damage to the detector and microscope, and without requiring a high level of user skill, knowledge, or training. Using the interface apparatus, the precise alignment, calibration, adjustment, and handling of equipment that is sensitive and prone to damage, may be performed during the installation of the apparatus on a particle beam instrument. The installation can be performed by a trained service engineer using specialist installation equipment, and subsequent removal, replacement, and insertion of one or more detector modules may be performed with ease, by a user of the instrument, with the alignment and means for guiding a new module into that alignment having been established already upon installation, and by virtue of the precise alignment and orientation by which a detector module may be mounted on the interface apparatus. Two key actions that are envisaged as being applicable to the use of the interface apparatus are: the replacement of a failed sensor head or failed detector module comprising a sensor head; and exchanging a sensor head or detector module for a different sensor head or detector module for a different application or adapted to monitor different types of signals or phenomena, or data of different quality (e.g. resolution), or to output different types of analytical data. The provision of an interface apparatus that may be permanently fitted to a particle beam instrument chamber, to facilitate user-removal of a module or sensor head in this way, presents a significant advantage compared to the unwieldy and demanding replacement and maintenance procedures with which users are confronted with conventional arrangements.

Accordingly, with the present interface apparatus, user-replacement of these components is possible without the need for an on-site visit by service engineers, thereby rendering these activities less costly and time-consuming. Likewise, detector modules and sensor heads adapted to be used with the interface apparatus may be designed and constructed with smaller and simpler structures, obviating any redesigning of apparatus components for alternative detectors for different applications. Additionally, a further advantage may be provided in that, in some embodiments, only one instrument chamber port may be necessitated for different detector technologies to be used with an instrument. This alleviates the issue of port availability being limited on many chambers, and the expense of microscope ports, for example.

It will be understood that the apparatus is referred to as an interface apparatus in that it relates to a device or apparatus connecting pieces of equipment, or adapted to connect pieces of equipment, so that they can be operated jointly or in communication with each other. In preferred embodiments, this relates to an instrument or microscope port interface in particular, such as an interface that connects an insertion/retraction mechanism and a detector module so that the sensors can be reliably and safely removed, inserted, and replaced through the port. The interface, or for example the guide mechanism thereof, may comprise components adapted to be affixed to a part of the particle beam instrument that is internal to the chamber, in some embodiments. For example, it may be fixed to the polepiece or chamber walls of an electron microscope. Such components may be configured to ensure that final alignment to an analytical position is achieved, that is, to guide movement of the mounted detector module into its final position. In preferred embodiments, however, the guide mechanism, or at least a part thereof, is positioned, when the interface apparatus is installed on a particle beam instrument, external to the chamber of that instrument. The expression “in use” as used in the above context may be understood as referring at least to the guide mechanism of the interface apparatus being in use, and more generally to the use of the interface apparatus.

The first position being at a predefined location within a chamber of the particle beam instrument may be understood at that position being predefined with respect to the particle beam instrument or a part thereof, typically with respect to at least a part of the instrument chamber, such as a chamber wall to which the interface is installed. The location may be predefined with respect to one or more components of the instrument, or with respect to a predetermined position of any of those components, for example if such a component is moveable within the instrument, for instance a sample stage or a particle beam apparatus such as an electron beam source, in particular a polepiece thereof. The location of the first position may be predefined relative to a beam axis defined for a beam generated when the instrument is in use, or relative to a beam spot at which a beam impinges on a sample within the chamberwhen in use. It will be understood that the location of the first position is typically determined, that is set or chosen, upon the apparatus being installed in an instrument, since, following that installation, the interface apparatus, or at least a part thereof, is generally immovably affixed to the instrument. Thus installation establishes a predefined positional relationship (defining both relative position and orientation) between the interface apparatus and the instrument which, together with the predefined positional relationship between the interface apparatus and a detector module mounted thereto, predefines the location of the first position. The location of the first position within the instrument may be fixed, typically with respect to one or more parts or components of the instrument such as those noted above, or may be adjustable in one or more degrees of movement as described later in this disclosure.

The predefined orientation that the guide mechanism causes the mounted detector module to effect when the latter is at the first position may, similarly to the location of the first position, be predefined with respect to the particle beam instrument or any part or component thereof. In preferred embodiments the guide mechanism and/or the alignment member effects a predetermined orientation between the detector module in its first position and a beam axis of a generated particle beam in use. The guide mechanism and/or the alignment member are preferably configured such that the orientation of the detector module is maintained or at least constrained, preferably continuously, as it is moved along the guide path in use, in particular throughout its movement between the first and second positions. In other words, the guide mechanism is preferably configured to control the orientation of the mounted detector module while moving it along the guide path. This may be achieved by way of the geometry of the guide mechanism itself being configured to limit rotational movement of the alignment member and/or the detector module and/or a mounting part of the guide mechanism, for instance by limiting or otherwise limiting rotational movement relative to the insertion direction or to a tangent to the guide path at any given point thereon. That is, the guide mechanism may partly or wholly preclude any rotational movement of the mounted detector module that is not attributable to any curvature or changes in direction of the guide path itself, as the module is moved along it. The detector module orientation may thus be controlled, by the guide mechanism, along one or more portions of the guide path, preferably all of the guide path, including at two end points thereof, which may be defined at the first and second positions.

This control of the module orientation along the guide path may be thought of as the guide mechanism and/or the alignment member restricting the module to a respective predefined orientation at every position along one or more portions of the guide path, preferably along the entire guide path, and preferably along the path or a portion thereof that extends continuously or discontinuously between the first and second positions.

Controlling the orientation of the mounted detector module in this way advantageously enables the action of moving the detector module in a first direction (which may be called an insertion direction) along the guide path, typically to an end point or limit thereof, to cause the detector module, and particularly the sensor head thereof, to be conveyed to a predefined position and orientation within the instrument, typically an analysis position. Conversely, this advantageous configuration of the alignment member and guide mechanism enables the action of moving the mounted module in a second, reverse direction (which is opposite to the first direction and may be called a retraction direction) along the guide path, typically to another end point thereof, or at least past an intermediate location thereon, to cause the detector module to be conveyed out of the instrument and to an external position or range of external positions, at which the module is user-accessible.

The interface apparatus is typically configured to have the detector module mounted to it at the second position, at least, or is configured such that mounting the detector module to the interface apparatus using the alignment member and at a mounting position external to the instrument chamber positions the detector module at the second position. Accordingly, the alignment member may be arranged to effect the first predefined orientation of the mounted detector module, with respect to any one or more of, or one or more parts of any one or more of: the alignment member, the guide mechanism, the interface apparatus, and the instrument, when the mounted detector module is at the second position. Preferably the module may be mounted to the mechanism at a range of positions along the guide path, particularly ones external to the instrument chamber. Where the guide mechanism is configured to guide the orientation of the module as it travels along the guide path, the predefined said second position and corresponding predefined orientation of the mounted detector module when at that second position, may be defined as any of a range of positions and corresponding orientations along an exterior (that is outside of the instrument chamber and/or an insertion mechanism of the apparatus) portion of the guide path. That is to say, the second position need not necessarily be fixed with respect to a component of the interface apparatus and need not necessarily be restricted to an exterior end point of the guide path that may be defined by an end of the guide mechanism, or by a blocking member or the like.

It will be understood that in various embodiments the first predefined orientation may be the same as, or different from, the second predefined orientation. Where they are the same, the movement may be purely translational, and not rotational, that is the apparatus may be adapted to maintain the detector at a consistent orientation while moving it between the first and second positions. In some cases, the said movement may cause or allow some rotation of the detector as it is moved along the guide path, but this may be effected such that there is net-zero rotational movement between the first and second positions. That is to say, the first and second orientations may be identical either by way of the apparatus causing purely translational motion, or by way of it effecting rotational motion with a net result of zero change in orientation. Alternatively, the first and second orientations may be different, for example with the first being chosen for ease of access to the sensor head, or with the second being chosen so as to effect an orientation suitable or optimized for analysis within the instrument.

In some preferred embodiments, the apparatus, in particular the guide mechanism, comprises an insertion/retraction mechanism. Typically, the insertion/retraction comprises a plurality of parts adapted to move in cooperation to cause the described movement of the mounted detector module. An insertion/retraction mechanism may comprise parts including any one or more of: a chassis, a bellows, and a slide assembly, for example, as is known in the art. In such embodiments, the mechanism is advantageously configured, and, in use, precisely aligned to the instrument, such that the insertion and retraction actions for which it is generally purposed are directed specifically along the guide path, and between the first and second positions. The guide mechanism is preferably provided as a dedicated guide mechanism configured to move the mounted module along the guide path. That is, the guide mechanism is preferably separate from any mechanisms or components of the particle beam instrument that may be provided for other purposes, such as those adapted to support, move, position, or manipulate a specimen, for example a sample stage. In other words, preferably the guide mechanism is independent of, and can effect, control, or guide movement of the mounted detector module independently from, any such components or mechanisms, and preferably does not comprise or form a part of them.

In some embodiments, the apparatus does not include an insertion/retraction mechanism as such, as is described later in this disclosure.

As alluded to above, the instrument is typically a particle beam microscope, such as an electron microscope. The interface apparatus may also be applicable to other equipment, such as optical microscopes, wherein the operative photons of light may be considered to be particles and form a particle beam in use.

The said second position being external to the instrument may be understood as meaning that at least a part of the detector module mounted to the interface apparatus, and in particular a sensor head thereof, is outside of the instrument, and preferably outside of any part of the interface apparatus such as an insertion mechanism, when it is at the second position. Preferably the apparatus is configured to provide adequate distance between the second position and the particle beam instrument to which the interface is affixed in use to provide enough clearance to enable easy and unobstructed access to the detector module or a sensor head thereof, in order to facilitate replacement and exchange of detector components by a technician user.

Preferably, the interface apparatus is configured to be mounted to a port of the particle beam instrument throughout the service life of the instrument. This may be effected, for example, by way of the permanence of the fixings by which the interface apparatus is adapted to be installed on the instrument. Typically, those fixings, or the fixing means by which the apparatus is installed on the instrument is such that movement of the interface apparatus relative to the instrument that could alter the first position relative to the instrument, is restricted or precluded.

Typically, the first position, the guide path, and the second position are located within a guide volume, the geometry of which contains the detector module when in the first position, the second position, and at all intermediate positions along the said path. Preferably, the guide volume is wholly or partly defined by a projection through three-dimensional space, along a direction of insertion and/or the guide path, of a lateral cross section defining the extent, typically the maximum extent, of the mounted detector module in two dimensions orthogonal to the direction of insertion and/or guide path. The guide volume may therefore be provided as a motion guide comprising one or more walls, members, or moving parts, arranged to abut, so as to guide, one or more parts of the mounted detector module as it is moved along the guide path. However, in some embodiments, the guide volume may represent a three-dimensional region of space defined as a plurality of locations that are occupied by at least a part of the mounted detector module at a given point during the movement of the mounted detector module between the first and second positions. Preferably, the guide volume is provided, and/or the interface apparatus is adapted to be installed on the instrument, such that no other component of the instrument, or any other component, coincides with the guide volume, at least in normal use.

Typically, in such embodiments, the interface apparatus is configured such that each of a plurality of different detector modules with different geometries may be moved between the first and second positions whilst being contained within the guide volume so as to enable the said different detector modules to be used within the particle beam instrument.

This may be understood as the apparatus being configured such that the guide volume is sufficiently large to completely contain the detector module, at least in a first and second dimension orthogonal to a longitudinal direction of the guide volume, which is typically parallel with the guide path at any given path along it. Some types of detector modules that may be used with the apparatus are typically larger in one or more dimensions than others. Preferably, the guide volume is configured to have sufficient extent in the dimensions orthogonal to the direction of insertion/retraction to be able to accommodate these multiple types.

In preferred embodiments, the guide path is linear. This may be thought of as the guide path comprising a linear portion, or being linear along its entire length. The term “linear” as used in this context may be understood as meaning arranged in or extending along a straight line. Thus, the guide mechanism may be configured when in use to move the mounted detector along a straight line. Preferably, the guide path is linear at least between the first and second positions. More preferably, the guide mechanism is arranged such that the movement of the detector module when the interface apparatus is in use is a translation, at least between the first and second positions, whereby a plurality of parts, preferably all parts, of a body of the detector module are caused to travel in the same direction, preferably without rotation and/or change of shape, as it is moved along the guide path.

In some embodiments, however, the guide path may additionally or alternatively comprise one or more curved portions, such that the interface apparatus is configured to cause the detector module to be moved translationally and/or rotated between the first and second positions.

Typically, the first position is within a predetermined distance of a particle beam axis of a beam generated by the particle beam instrument in use. The predetermined distance is typically chosen in accordance with a type or properties of one or more detector modules to be used. Preferably the predetermined distance is a maximum distance, or defines an upper limit on a component of the distance in a direction orthogonal to the instrument beam axis in use, or lying in a plane orthogonal to the beam axis, between the beam and the first position. Typically, alignment of the sensor head in the direction parallel to the beam axis is typically less critical than alignment orthogonal to the beam. The predetermined distance is generally 1 mm, preferably 0.5 mm, and more preferably 0.1 mm. The said beam axis may be understood as a geometrical axis parallel to the beam and coincident with a centre or centroid thereof, that is a centre or centroid in the dimensions orthogonal to the direction of beam propagation.

Advantageously, the interface apparatus may be adapted to be affixed to a port of an instrument of a particular type or dimensions, or having a particular shape, or fixing type. Preferably, the interface apparatus is adapted to engage with such ports, while providing adaptability and flexibility in terms of being able to accommodate the insertion, retraction, and replacement of various types of detectors with ease. Preferably, therefore, the interface apparatus further comprises one or more instrument port-specific parts. These instrument ports may be microscope ports in some embodiments.

Preferably, the first position is the position within the particle beam instrument in which the detector module is used during normal use, which may be called an analysis position or an analytical position. In other words, the interface apparatus may be configured such that moving the mounted detector module along the guide path and halting movement at the first position delivers the sensor head of the detector module to its analysis position. The guide mechanism may be configured to limit movement of the mounted detector module in the insertion direction, in particular by defining an end point of the guide path at the first position. This may be implemented by way of some form of blocking member or abutment of the interface apparatus adapted to prevent further movement of the mounted detector module in the direction of insertion beyond the first position. Preferably, the movement of the detector module to and from the first position, and generally the position of the module on the guide path or along a direction of insertion and/or retraction, is controlled by a motorized mechanism. Any of this mechanism, the guide mechanism, and the interface apparatus may be software-controlled, so that the controlled insertion and retraction of the module are automated and performable in the absence of user intervention.

In some embodiments, the apparatus further comprises an adjustment mechanism, which may be coupled to, or in some embodiments comprised by, the guide mechanism. The adjustment mechanism may be configured to change the first position, and/or move the mounted detector module from an initial, or preadjustment, position to the first position within the chamber, typically during installation of the apparatus on an instrument. The initial position may be called a third position. However, it will be understood that different ordinal identifiers may be applied as appropriate, depending on the embodiment. The apparatus may comprise a mechanism that facilitates its alignment to the instrument, in particular the axis of the instrument particle beam when in operation, upon initial installation. Preferably, once the adjustment mechanism has achieved the desired alignment, no further adjustments are made, such that the apparatus continues to provide the above-described advantages throughout the service life of the instrument.

In some embodiments, however, the apparatus may, in addition to providing this beneficial alignment, permit further adjustments, particularly user adjustments, to be made, by a technician for example. This may allow greater tolerances in manufacturing and/or installation of the interface upon the instrument, and can facilitate the positioning of sensors for use with greater precision. Accordingly, the apparatus may comprise an adjustment mechanism configured when in use to change the first position, and/or move the mounted detector module from the first position to an adjusted position within the chamber. This adjustment mechanism may comprise, or be the same as, comprised by, different from, or separate from, the aforementioned adjustment mechanism.

Preferably, the first predetermined orientation in which a detector module may be mounted (which may be understood as a predetermined orientation with respect to a part of the interface apparatus, in particular a mounting part, to which the detector module is mounted or mountable, and/or to the alignment member), the relative positioning of the first position with respect to the instrument and/or beam thereof, and an initial position and/or orientation with which the interface apparatus is affixed to the instrument, together allow continued and repeatably precise exchanging and insertion of detector modules by a technician user. It will be understood that the apparatus may enable a detector module to be reliably brought to a precisely predetermined position, and preferably orientation, from a position outside of the instrument. Advantageously, this obviates any additional adjustments to the inserted position of the detector module.

It is possible, however, in some embodiments, that the position and/or orientation effected by a module inserted into the instrument along the guide path might not be precisely the same as the position and/or orientation in which the module is used during normal use. For example, it may be proximal to that position, for instance within a sub-millimetre distance. However, further changes to the first position, subsequent to installation, to a final, or analysis position, might be preferred in order to achieve optimal alignment with the particle beam.

Therefore, in some cases it may be desired to be able to change the orientation and/or alignment of the detector module, particularly with respect to a microscope or particle beam, after the sensor head has been inserted between the polepiece and the sample holder.

In some embodiments, the apparatus may be configured such that, after the module is inserted using the guide mechanism, for example, additional refinement of the inserted position of the module, towards a desired or optimal analysis position for instance, is enabled. In this case, refinement may refer to improvement of the inserted position of the module by the effecting of small positional changes, potentially to orientation and/or position. Preferably, the apparatus facilitates fine adjustment of position at least in the direction of insertion. Therefore, preferably, the apparatus is configured to permit final adjustments in the “X” axis, which in some embodiments may be thought of as corresponding to the direction of insertion, retraction, or travel along the guide path, preferably by operating the retraction mechanism. For example, fine adjustments along or within an end portion of the guide path may be enabled. To this end, a mechanism may be provided that is adapted to control the position of the module along the guide path to a precision of, for example, 1 millimetre, 500 micrometres, or 100 micrometres most preferably. A fine adjustment mechanism comprised by the interface apparatus and configured to make such refinements to the detector module position along the X axis may comprise various adjustment components, in different embodiments. The fine adjustment mechanism may comprise any one or more of: an adjustable hard end stop, an adjustable microswitch, an adjustable flag, an opto-switch, and an encoder. Such components are preferably adapted to refine or adjust the inserted position of the detector module along the guide path, and are preferably adjustable in the sense that any control of, or restriction upon, the position of the detector module that is caused by those components is configurable, in particular user-configurable. A fine adjustment mechanism is typically provided in preferred embodiments that comprise an insertion/retraction mechanism. The mechanism, or a further mechanism, can be provided to enable corresponding fine adjustment in one or each of the spatial axes orthogonal to the aforementioned X axis.

As noted earlier, any adjustment mechanism is preferably suitable for initial attachment of the interface apparatus to an instrument. However, in some cases it may be beneficial to use such a mechanism to make adjustments after installation.

Additionally or alternatively, such an adjustment mechanism may be configured to alter the location of the first position with respect to the beam, beam assembly, and/or instrument. This may be possible before and/or after insertion. For example, the first position may be reachable, defined, or changeable by way of the adjustment mechanism. This may be changed, for example, within a range of positions, or within an end portion of the guide path as noted above, and/or within, and possibly restricted to, a one-, two-, or three-dimensional region proximal to an end of the guide path within the chamber. The adjusted position need not be predetermined. Rather, it may be determined as part of a method of using the apparatus. For example, it may be determined using optical or visual data, or confirmation of correct positioning with respect to the beam. It may be defined by a corresponding point, length, area, or volume within the chamber that represents the acceptable tolerance.

Typically, the adjusted position lies on the guide path. This may be understood as being defined in terms of a point position corresponding to a position of the mounted detector module when it is in the analysis position. Any point or position on the guide path may be defined in such terms. That is to say, a position may be defined as a point on a line representing the guide path at which a part of the detector module is located when the detector module is said to be in that position. The part may be, for example, a fiducial part of, or location within, the detector module, or a part of the interface apparatus to which it is mounted and/or which is configured to move with it, and/or typically configured with respect thereto.

As an alternative mode of adjustment by the adjustment mechanism, or by a different adjustment device, the adjustment mechanism may, in some embodiments, be configured when in use to move the mounted detector module to the adjusted positioning through one or more translational or rotational degrees of freedom. It may be configured in particular to control the movement of the mounted detector module, or a part of the interface apparatus to which such a module is mountable, preferably within a higher degree of positional precision. The aforementioned degrees of freedom may be understood as being any one or more of the three degrees of translational movement and the three degrees of rotational movement. The relative orientation of any of these degrees of freedom may be defined with respect to any one or more of the guide path, the guide member, and the beam assembly, and the beam axis of the instrument.

In some embodiments the interface apparatus may be configured to retract a detector module away from the analysis position to a partially retracted position within the instrument chamber. Thus, the interface apparatus, and in particular the guide mechanism, may be configured, when the guide mechanism, and more generally the interface apparatus, is in use, to move the mounted detector module along a portion of the guide path between the first position and a partially retracted position. The interface apparatus may also be configured to move the mounted detector module along a retraction path at least part of which is coincident with the portion of the guide path. The retraction path may extend beyond the portion of the guide path, for example in order to effect further movement in the direction of insertion, past the first position, and/or in the direction of retraction, which may be understood as being antiparallel to the direction of insertion. The retraction path and partially retracted position may accordingly, in some embodiments, be referred to respectively as a removal path and a partially removed position, in the sense that they relate to removal of a detector module from the immediate vicinity of the beam, without necessarily retracting it to the second position, and not necessarily along the direction of retraction.

Typically, the detector module comprises a sensor head which is replaceable by a user. The term “user” in this disclosure generally refers to a user of the instrument, typically a technician. This will be understood as being distinct from an installer or engineer that may affix the interface apparatus to the instrument at the start of its service life.

Detector modules comprising sensors adapted to monitor or be sensitive to various types of particles may be inserted, positioned, or replaced using the interface apparatus in preferred embodiments. For example, sensors adapted to indicate specimen crystal structure and orientation, atomic number, and chemical element composition may be provided that are adapted to be mounted on, and inserted using, the interface apparatus.

Typically, the guide mechanism comprises one or more alignment rods. However, it will be understood that other types of guiding components may be included alternatively or additionally. For example, any one or more of a tube, a rail, a shaft, a bushing, a bearing, and any form of linear guide, rotary guide, and curve guide may be comprised by the guide mechanism, and/or by the alignment member.

Preferably, the guide mechanism is configured to be selectively detachable from the interface apparatus. This may refer to the guide mechanism being removably mountable to the interface apparatus. This will be understood as being in part or in full in preferred embodiments. In other words, the guide mechanism may be adapted to be removably equipped to the interface apparatus, that is attached for use and detached, by a user. The guide mechanism may consequently be thought of as a temporary guide mechanism in some embodiments.

Typically, the interface apparatus, in particular the alignment member and/or the guide mechanism thereof, comprises a set of one or more interface elements, which may be called alignment elements and/or guide elements, for both the interface and the module, adapted for cooperation with a corresponding set of detector module elements so as to direct the movement of the mounted detector module along the guide mechanism and into the first position, or along the guide path and into the first position. Typically, this is configured to cause or contribute to the mounted detector module effecting the second predetermined orientation, with respect to the instrument, when in the first position.

An interface element typically comprises at least one component of any one or more of: a chassis, a bellows, and a slide assembly. It will be understood that any of these components may comprise cooperating or complementary interface elements and module elements.

Typically, the interface apparatus further comprises a selectively demountable transport capsule, the capsule being configured to be mounted to the interface apparatus and/or to the detector module, such that the detector module may be moved, in some embodiments partly or entirely by the guide mechanism, inside the transport capsule and detached from each of the alignment member and guide mechanism so as to enable removal of the detector module from the instrument. More generally, the capsule may be configured to be mounted to the interface apparatus such that relative movement of the transport capsule with respect to the detector module may be caused such that the transport capsule partly or entirely encloses, surrounds, or covers, the detector module. This relative movement may comprise movement (with respect to the instrument or other parts of the interface apparatus, for example) of one or each of the detector module and the transport capsule, and is preferably effected by a mechanism, particularly the guide mechanism, comprised by the interface apparatus. The capsule itself, or any separate equivalent device, may provide electrostatic discharge (ESD) protection. The capsule may in some embodiments be mountable to the interface so that it is held safely whilst the detector module is slid into it, thereby minimising the required physical contact with the detector module.

The guide mechanism, which may be temporary or permanent, as alluded to above, may in some embodiments be provided together with a second guide mechanism. For example, in preferred embodiments, a permanent guide mechanism incorporated into the interface apparatus is provided, while the interface apparatus further comprises a temporary, selectively detachable, module removal guide mechanism. Thus a temporary guide mechanism may be configured when in use to move the mounted detector module along a second guide path into the transport capsule. A position at which the detector module is held, or secured, within the transport capsule, or is at least partly enclosed by the capsule, may be thought of as a third position.

The interface apparatus may further comprise an interface connector for providing, when in use, one or more electrical connections to a complementary module connector of the detector module, wherein the said interface connector and detector module may be together arranged so as to protect the detector module from damage caused by electrostatic discharge.

Typically, the guide mechanism further comprises a service position along the transport path which is external to the instrument chamber, such that, when the detector module is positioned within the service position, a user may access, that is, may have adequately unobstructed access to allow removal, replacement, or installation of, a sensor head of the detector module.

Preferably, the apparatus is adapted to avoid unnecessary damage to the sensor or detector module, generally from particles, typically electrons and/or X-rays. Thus, the guide mechanism is preferably configured, when the sensor is not in use, but, typically, when the beam is operational, such as if the sample is being changed or moved, to move the mounted detector module away from the first position, typically to a distal position, which may be on the guide path at a location more distal to the beam axis than the first location. The moving “away” from the first position may be understood typically as being along the guide path, in particular in the direction of retraction. The apparatus may comprise a controller and one or more actuators configured to effect this movement automatically, that is without directing useful input.

In accordance with a second aspect of the invention there is provided an interface apparatus for a particle beam instrument, the interface apparatus comprising: an alignment member for causing a detector module of the particle beam instrument to be mounted to the interface apparatus in a predefined orientation; a guide mechanism configured when in use to move the mounted detector module along a guide path between a first position, within a chamber of the particle beam instrument, and a second position; and an adjustment mechanism configured to move the mounted detector module between the first position and a third position that is within the chamber.

The interface apparatus, like that according to the first aspect, can facilitate low- risk, on-site, user (technician) replacement of a detector module or sensor head. Likewise, owing to the positional precision with which the apparatus can manipulate the detector module, the apparatus, when installed precisely on a particle beam instrument, typically by way of a factory installation or by a service engineer, enables easy and precise insertion of modules to an analysis position and retraction to a service position. The interface apparatus according to the second aspect may guide the movement of the module along a guide path that may be partially or wholly internal to the instrument chamber, while advantageously providing the capability for fine adjustments to the positional relationship between the interface apparatus and the instrument to be made during installation of the apparatus. Thus the alignment of the apparatus on the instrument, and in particular the “inserted” position of the detector module, that is the first position, defined thereby, may be established with greater precision upon factory installation or during installation by a service engineer, typically at the beginning of the service life of the instrument. In this way, a simplified, more compact interface apparatus that also facilitates the first position being predefined so as to correspond precisely to a desired or optimal analysis position for the detector module or sensor head, is provided. Typically, the guide mechanism and/or alignment member are provided within the instrument chamber. In this way, the extent of the range of positions at which a position and/or orientation of the detector module is constrained by the guide mechanism and/or alignment member may be limited to being within the chamber also. In other words, the guide path may form only a portion, typically a portion internal to the chamber, and preferably at an end segment including an endpoint, of a path of motion of the detector module between analysis and fully retracted positions. That is, for at least a portion of a path of insertion and/or retraction, between the second position and an external position, or fully retracted position, the position and/or orientation of the detector module, and/or its translational and/or rotational motion, may be unconstrained, or less constrained than along the guide path. The second position may be a predefined position within the chamber and may correspond to a predefined orientation of the detector module with respect to the instrument or chamber when the detector is mounted and at that second position.

Thus the second position may be a position external to the instrument chamber, or more typically a position within the instrument that is different or distal to a position at which the detector module is located with respect to the particle beam, in normal use. In some embodiments, when the second position is adopted, the detector module or at least part of it is external, however. Nevertheless, the second position may be partly internal to the instrument, that is, when the second position is adopted, the detector module may be partly internal to the chamber, and in general the second position need not be defined or restricted in terms of it being internal or external relative to the instrument or chamber thereof.

The adjustment mechanism may facilitate adjustments to the inserted position and/or orientation of the detector module, as described earlier in connection with the first aspect, and may advantageously be used for pre-alignment of the apparatus with respect to the instrument and its components. Typically, during installation of the apparatus on an instrument, the installer initially positions the apparatus such that the internal end of the guide path is distanced from components within the instrument chamber such as the polepiece of an electron microscope, in order to avoid accidental collisions between such components and the apparatus or a detector module which is typically mounted thereto. Thereafter, usually after the apparatus has been affixed to the instrument, the installer typically adjusts the apparatus, using the adjustment mechanism, so as to move the internal end of the guide path, or the location of the mounted detector module when it is at that end of the guide path, from that initial, safe position within the chamber, which may be thought of as the said third position, to the first position. The first position is therefore typically closer than the third position to an analysis position. For instance, the third position is generally chosen by an installer to be deliberately lower within the chamber than the desired analysis position, and, those safety tolerances may then be removed by way of precise positional adjustment by the installer using the adjustment mechanism. In this way the mechanism may be used to establish the analytical first position to which subsequent insertion using the apparatus will bring the detector module.

In accordance with a third aspect of the invention there is provided a method of replacing a detector module in a particle beam instrument using an interface apparatus according to the first aspect, the method comprising: a. operating the guide mechanism to remove a first detector module from the particle beam instrument chamber; b. detaching the first detector module from the guide mechanism; c. attaching a second detector module to the guide mechanism and aligning the second detector module using the alignment member so as to achieve the predetermined alignment for the second detector module; and, d. moving the second detector along the guide mechanism to place it in the first position for use.

The second detector module may be different from the first detector module. For example, where one detector module is being replaced with another, of a different sensor type for example, or to replace a non-working component. The second detector module may be one and the same as the first detector module, typically having undergone some repair or maintenance between steps b and c. The method may in this way be one of replacement or repair.

In some embodiments, the interface apparatus further comprises a selectively demountable transport tube, as described above, for example, in relation to the first aspect. Such embodiments of the method may therefore be particularly suited to being performed using an interface apparatus according to those embodiments of the first aspect. Accordingly, the method may further comprise, mounting the capsule, which may optionally contain some guiding means, to the interface apparatus, and/or to the first detector module. The method may further comprise moving the first detector module inside the transport capsule, and detaching the first detector module from each of the alignment member and the guide mechanism, typically so as to enable removal, which may be understood as the detachment at step b, of the detector module from the instrument.

In accordance with a fourth aspect of the invention there is provided a method of replacing a sensor head of a detector module in a particle beam instrument using an interface apparatus according to the first aspect, in particularwherein the guide mechanism further comprises a service position along the transport path which is external to the instrument chamber, such that, when the detector module is positioned within the service position, a user may access a sensor head of the detector module, the method comprising: a. operating the guide mechanism to remove a first detector module comprising a first sensor head from the particle beam instrument chamber and place it in the service position; b. detaching the first sensor head from the first detector module; c. attaching a second sensor head to the first detector module; and, d. moving the first detector module with the second sensor head along the guide mechanism to place it in the first position for use.

The second sensor head may be different from the first, for example where one sensor head is being replaced with another. The second sensor head may be one and the same as the first sensor head, typically having undergone repair or maintenance as described above.

Preferably the second sensor head is provided with a selectively removable cover surrounding at least the sensor of the sensor head and, preferably, during step c, the cover remains surrounding the sensor head while the sensor head is attached to the detector module, and preferably, step c further comprises removing the cover prior to step d.

Typically, prior to step (a) the detector module is packaged in a remote location including each of: a. the provision of thermal and electrical joints; and, b. a sensor of the detector module is aligned such that when the detector module is aligned with the alignment member of the interface module, the detector module will be correctly aligned in the instrument when the detector module is in the first position. The remote location is typically located at a service or manufacturing site. In accordance with a fifth aspect of the invention there is provided a detector module adapted for use with an interface apparatus according to the first aspect, and comprising a selectively removable sensor head, the detector module being provided with a selectively removable cover surrounding at least a sensor of the sensor head.

In accordance with a sixth aspect of the invention there is provided an interface apparatus for a particle beam instrument, the interface apparatus comprising: an alignment member for causing a detector module of the particle beam instrument to be mounted to the interface apparatus in a predefined orientation; and, a guide mechanism configured when in use to move the mounted detector module along a guide path between a first position, within a chamber of the particle beam instrument, and a second position external to the instrument. Any features of the apparatuses or methods provided in accordance with any of the preceding aspects may be provided as part of the apparatus according to the sixth aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

Examples of the present invention will now be described, with reference to the accompanying drawings, in which like features are denoted by like reference signs, and in which:

Figure 1 is a schematic diagram showing a first example interface apparatus according to the invention, in side view;

Figure 2 shows the first example interface apparatus in perspective view;

Figure 3 is a flow diagram showing an example method of replacing a detector module in a particle beam instrument using an interface apparatus according to the invention;

Figure 4 is a schematic diagram showing the first example interface apparatus at three stages of the first example method; Figure 5 is a perspective view of part of a second example interface apparatus according to the invention that comprises a selectively demountable transport capsule;

Figure 6 is a perspective view of an example detector module adapted to be used with an interface apparatus according to the invention;

Figure 7 is a perspective view showing part of a further example detector module during replacement according to an example method; and

Figure 8 is a schematic side view of a third example interface apparatus according to the invention.

DESCRIPTION OF EMBODIMENTS

With reference to Figures 1-8, examples of interface apparatuses and methods according to the invention are now described.

A first example interface apparatus is shown schematically in Figure 1. The interface apparatus 101 is installed on a particle beam instrument 103, which in the present example is an electron microscope. The apparatus 101 is coupled to the microscope 103 via a microscope port interface 102. The interface apparatus 101 comprises a generic insertion mechanism, which is so called owing to its capability for effecting the insertion of various types of detector module 107 into the electron microscope 103. The common design of the interface apparatus can accordingly accommodate various different detector module designs, for example EDS, BSED, and EBSD detectors. This is because all of these types of detector require access to the same part of the microscope chamber, good electrical and vacuum paths, retraction and insertion, and fine alignment to the electron microscope, particularly the beam thereof. Additionally, both EDS and EBSD detectors also need to maintain a good thermal path and require ESD protection.

The retraction and insertion of a detector module 107 may be performed using the guide mechanism 109. In the present example this comprises a generic bellows adapted to accommodate different types of detector module as it is moved along the guide path from an external position to an internal position within the chamber of the microscope 103.

The capacity for adjustments to the position and orientation of the interface apparatus is provided by the adjustment mechanism 112, which in the present example is provided as a generic alignment stage, or “YZ stage”, that is not specific to the detector or sensor types. Such adjustments are typically made during installation of the apparatus 101 , in order to effect an installed orientation of the interface apparatus with respect to the instrument 103. Fine positional and/or orientation adjustments may be made by the installer in order to achieve precise alignment of the detector module to the instrument beam in use. Moreover, the adjustment mechanism can be used to improve alignment or remedy misalignments that may be caused by apparatus component defects, for example.

In the present example the specific sensor head 113 is affixed to the detector module 107, and the interface apparatus 101 is geometrically configured to guide the insertion of the detector module into the chamber of the microscope 103 such that the sensor head 113 arrives with a predetermined position and orientation with respect to the beam axis of the microscope. It is also envisaged that specific sensor heads 113 may be interchangeably mounted to the specific detector module 107.

The interface apparatus 101 , and in particular an alignment member 104 thereof, is adapted to receive a correspondingly shaped part 108 of the detector module in such a way that the receipt of that part by the alignment member, and generally the receipt of the detector module 107 by the interface apparatus 101 , causes the detector module 107 to be mounted in the interface apparatus 101 in a predetermined orientation. In the present example the alignment member comprises a bushing shaped to effect an interference fit or a transition fit between it and the module component 108. Other detector modules (not shown) with which the depicted detector module 107 may be replaced may generally have a mating component having the same shape and a corresponding orientation with respect to the detector module as the mating component 108, so that different detector modules may be used with the insertion mechanism 101.

The detector module 207 is shown in a different unmounted state in Figure 2. It can be seen that the sensor head 113 has been inserted into the interface apparatus 201 and is within a region defined by the generic bellows 215. Additionally shown in Figure 2 is an electrical connector 219 which, in the present example, is provided as an ESD-safe electrical connection. This is provided as a jack protruding from the module 207 and positioned so that it is received by a corresponding electrical connector socket 220 of the interface apparatus when the detector module is mounted to the interface apparatus. The jack 219 and socket 220 may be correspondingly shaped so as to comprise, or be comprised by, the alignment member of the insertion mechanism 201 and a corresponding alignment component of the module 207, that is to say they may contribute to the alignment to the predefined orientation effected when mounting the module 207. The spatial axes shown denote the X axis as being parallel to the direction of insertion and retraction of the module into the microscope chamber, with Y and Z axes being orthogonal thereto and to each other. The direction of retraction is indicated by the arrow in Figure 2 and the direction of insertion is indicated by the arrow in Figure 1.

Accordingly, with the example apparatus, the detector design is effectively separated into a detector module and a standard or generic design of the interface apparatus, containing a microscope port-specific part, and generic alignment mechanism, chassis, bellows, slide/retraction assembly, and module alignment features. The interface apparatus adjustment mechanism 112 is aligned to the microscope chamber 103, and preferably aligned with respect to a polepiece or particle beam axis when in use, of the microscope 103. This alignment may be performed on initial installation, for example by a service engineer. The entire interface 101 is adapted to remain attached and aligned at all times after installation. In this way, the previously described issues encountered in existing arrangements, whereby skilled service engineers are required for the demounting of detector units and the alignment of replacement sensor heads, and recalibration thereof, is overcome.

An example replacement process is shown by the flow diagram in Figure 3. According to this process, only the detector module 107, which is typically much lighter in weight and more practical to handle and replace, needs to be retracted outside of the chamber, using the guide mechanism of the interface apparatus 101 , thereby preventing accidental damage to the detector or microscope.

An example replacement method 300 commences with the guide mechanism being operated 301 to remove a first detector module from the chamber of the particle beam instrument 103, 203. In Figures 1 and 2, the bellows 109, 209 is in an extended state, and the receiving part 104, 204 of the interface apparatus is distal to the microscope port interface 102. The effecting of this extended position of the receiving part 204 corresponds to the second position described earlier in this disclosure, whereby the detector module 207 is outside of the chamber of the microscope 103, 203. In different examples, the interface apparatus may be configured such that the second position is one at which the mounted detector module is at least partially within the chamber of the microscope 103. The second position is typically further along the guide path, in the retraction direction, than the first position. The first position is typically the analysis position.

The direction of removal (or retraction) of the first detector module 207 is indicated by the arrow in Figure 2.

Subsequently, at step 302, the first detector module 207 is detached, or dismounted, from the guide mechanism and the interface apparatus 201 . In this way the detector module 207 may be readily extracted from the instrument 203 for repair or replacement purposes.

At step 303 a second detector module 407a is provided, and attached to the guide mechanism and aligned using the alignment member of the interface apparatus 401 as shown at stage A in Figure 4. The mounting direction of the replacement detector module 407a, the sensor head 413a of which may be different from that of the first detector module, is indicated by the arrow in Figure 4. Owing to the detector module 407a being provided with the same generic mating parts for engagement with the alignment member of the interface apparatus 401 as the first detector module 407, a precise alignment may be achieved without making relative adjustments for different detector modules. Thus at 303 the predetermined alignment is achieved for the second detector module also.

Stage B in Figure 4 depicts the second detector module 407a in its mounted state, and in the second position.

At 304 the second detector 407 is moved from the second position shown at stage B, along the guide mechanism, to place it in the first position, shown at stage C, for use. It can be seen that the bellows is contracted and the protruding part of the detector module 407a including the sensor head 413a has been inserted to a position suitable for analysis of a specimen with the beam of the instrument 403 in operation. A detector module that is removed may be stored and transported in a transport capsule. A method of removing a detector module 507 is shown at four stages in Figure 5. A capsule containing a replacement or different type of detector is mountable in a procedure that may be considered to be the reverse procedure of the detector mounting process. The common alignment features on the interface apparatus 501 , which may be understood as alignment members, ensure that the new detector is positioned correctly and no user alignment is required during replacement.

At stage A in Figure 5, a temporary guide mechanism 514 is inserted, as indicated by the arrow. In the present example, the temporary guide mechanism 514 is provided in the form of a rod arrangement. However, any suitable guide mechanism may be used in different examples. At stage B in Figure 5, the detector module being removed 507 is disconnected from the interface apparatus and withdrawn along the temporary guide mechanism 514 as indicated by the arrow.

At stage C, the aforementioned ESD-safe capsule 517 is placed over the detector module 507 and secured. This may be achieved by any suitable securing device or fixing. The placement of the capsule 517 over the module 507 is indicated by the arrow at stage C. In other examples, rather than the detector module entering the transport capsule by virtue of the latter being placed over the former, the detector module may be moved into the capsule, which may optionally be secured to the interface apparatus for this purpose. This movement may comprise a further movement of the module in the retraction direction, for example using the guide mechanism or a temporary guide mechanism.

Also visible at stage C is the sensor head 513 of the first detector module 507, owing to the module 507 having been retracted from the apparatus 501 . At stage D, with the module secured within the capsule 517, the module is unclipped from the temporary guide mechanism 514 and removed therefrom, as indicated by the arrow. The module may then be shipped back to a repair centre for example.

In various examples, the guide mechanism may be temporary or permanent, and generally ensures that the detector module can be retracted and removed without risk of damage to the detector or the microscope. A rear catch 625, as shown in Figure 6, at the end of the guide mechanism distal to the interface apparatus 501 and in particular the receiving part thereof, may be used in some examples in order to prevent accidental removal of the detector module from the guide mechanism.

A detailed view of an example detector module that is adapted to be used with an example interface apparatus according to the invention is shown in Figure 6. The module is shown with the temporary guide mechanism 614 in position for removal of the module 607. The module is a detector-specific module containing electronics and thermal management. In the present example, the guide mechanism of the interface apparatus, which is only partially shown, comprises guide rods 621. Rotational alignment and ESD protection are provided by the protruding module components 616 either side of the common guide spigot 616a of the module, from which the detector-specific tube 624 extends. A seal is provided in the form of a common 0-ring 616b, and common fixing holes 616c are provided in the mounting end of the module 607. These detector module components 616 are common to multiple detector modules adapted to be mounted to the example interface apparatus. In other words, the interface apparatus, particularly the alignment member or arrangement of alignment members thereof comprises one or more interface elements adapted for cooperation with the set of detector module elements 616.

In preferred examples, all critical, thermal, heat path, and electrical joints in the detector module are made in the factory in which the module is produced. The positions of the sensors 513 relative to the common alignment features 616 are jig aligned in the factory to ensure that the different types of detectors are located and positioned correctly with respect to the interface apparatus, and therefore also, owing to the alignment between the interface apparatus and the instrument 103, to the chamber, the polepiece, and the particle beam in use.

The detector module includes a protection arrangement adapted to ensure electrical contacts between the module and the interface apparatus are made without risk of ESD damage. Final vacuum sealing of the module 607 to the interface apparatus can be made by the simple O-ring 616b seal, or a copper gasket, in other examples, for UHV (ultra-high vacuum) chambers. As noted above, these features are common between the different detector modules.

An alternative sensor replacement process is shown in Figure 7. In this alternative replacement process, the above-described steps can be used to retract the detector module 707 on the guide mechanism 709, which may be a temporary guide mechanism, sufficiently for a user to gain access to replace the sensor head 713 itself on the detector module. The sensor head 713 may be replaced while the module is safely outside of the microscope chamber. In Figure 7, the sensor head is depicted in a detached state, with fixings and electrical connection components, on both the sensor head 713 and the module 707, and configured to engage one another, disconnected. Preferably the detector module 707 is provided with components for coupling to sensor heads and establishing electrical and data communications with them through connecting or mating parts that are common to different types of sensor head. After the sensor head has been replaced, the detector module may then be reinserted into the generic interface apparatus 701 . This alternative replacement process is useful as it mitigates the problem of access to replace a sensor head inside the instrument chamber often being very limited, with the risk of damage to a detector or microscope being high.

Further protection for the sensor head 713 may be provided by way of the protective cover 723 adapted to fit over the sensor head 713 and adapted such that the sensor head 713 may be securely held therein, thereby permitting the sensor head to be held, carried, manipulated, and attached or detached from the detector tube 724.

A further example interface apparatus arrangement, suitable for small-chamber microscopes, is shown in Figure 8. Typically, in such microscopes, an insertion/retraction mechanism is not required. In such a case, rather than having a bellows, sliding guide, or other moving parts of a insertion/retraction mechanism, as comprised by the guide mechanism in preceding embodiments, the interface apparatus may instead comprise a static mounting plate 809. The mounting plate 809 is configured to move the mounted detector module along a guide path at least partly concurrently with the insertion or mounting of the detector module 807 into the interface apparatus 801 . In this example, therefore, the guide mechanism and the alignment member may share one or more components, the alignment member may comprise the guide mechanism, or vice versa, or the two may be one and the same.

The mounting plate 801 includes the common detector module mounting features adapted to receive the module 807, and a simple 0-ring seal.

In such examples, the above-described temporary guide mechanism and module removal procedure may typically be the same.

In a further example process for module replacement, a simple under-polepiece sensor may be replaced without the requirement for access to the chamber in the manner described above. In such examples, the interface apparatus may be used essentially as a push-rod adapted to manoeuvre a sub-polepiece sensor head of a detector module into a fixed socket under the polepiece, without accessing the chamber. In this way, the socket under the polepiece may constitute or comprise the guide mechanism and/or the alignment member. In this way, the socket is typically both: configured to cause a detector module to be mounted to the interface apparatus in a predefined orientation; and adapted to move the mounted detector module along a guide path between a first position and a second position. That is, the predefined orientation may be understood as being defined by the module being directly or indirectly fit to, or engaged by, the socket. Likewise, the first position may correspond to a position at which the engagement part of the module is fully inserted or engaged by the socket, and the second position may correspond to a position at which the module is directly or indirectly engaged within the socket and is not fully inserted. Accordingly the interface apparatus is preferably adapted to prevent further movement of the module in the direction of insertion beyond the first position. The push-rod can additionally be used to remove a failed under-polepiece sensor to replace it with a working sensor. This may be suitable for a simpler sensor, such as a BSED sensor.

Claims

1. An interface apparatus for a particle beam instrument, the interface apparatus comprising: an alignment member for causing a detector module of the particle beam instrument to be mounted to the interface apparatus in a first predefined orientation; and, a guide mechanism configured when in use to move the mounted detector module along a guide path between a first position at a predefined location within a chamber of the particle beam instrument, and a second position external to the instrument, such that the mounted detector module effects a second predefined orientation, with respect to the particle beam instrument, when at the first position.

2. An interface apparatus according to claim 1 , wherein the first position, the guide path and the second position are located within a guide volume, the geometry of which contains the detector module when in the first position, the second position and at all intermediate positions along the said path.

3. An interface apparatus according to claim 2, wherein the interface apparatus is configured such that each of a plurality of different detector modules with different geometries may be moved between the first position and the second position whilst being contained within the guide volume so as to enable the said different detector modules to be used within the particle beam instrument.

4. An interface apparatus according to any of the preceding claims, wherein the guide path is linear.

5. An interface apparatus according to any of the preceding claims, wherein the first position is within a predetermined distance of the particle beam axis in use.

6. An interface apparatus according to any of the preceding claims, further comprising one or more instrument port-specific parts.

7. An interface apparatus according to any of the preceding claims, wherein the first position is the position within the particle beam instrument in which the detector module is used during normal use.

8. An interface apparatus according to any of the preceding claims, wherein the apparatus further comprises an adjustment mechanism configured to move the mounted detector module from an initial position within the chamber to the first position.

9. An interface apparatus according to any of the preceding claims, wherein the guide mechanism is configured when in use to move the mounted detector module along a portion of the guide path between the first position and a partially retracted position.

10. An interface apparatus according to any of the preceding claims, wherein the detector module comprises a sensor head which is replaceable by a user.

11. An interface apparatus according to any of the preceding claims, wherein the detector module comprises an energy-dispersive spectroscopy, EDS, detector, backscatter electron detector, BSED, or electron backscatter diffraction, EBSD detector.

12. An interface apparatus according to any of the preceding claims, wherein the guide mechanism comprises one or more alignment rods.

13. An interface apparatus according to any of the preceding claims, wherein the guide mechanism is configured to be selectively detachable from the interface apparatus.

14. An interface apparatus according to any of the preceding claims, wherein the interface apparatus comprises a set of interface elements adapted for cooperation with a corresponding set of detector module elements so as to direct the movement of the mounted detector module along the guide mechanism and into the first position.

15. An interface apparatus according to claim 14, wherein an interface element comprises at least a component of any one or more of: a chassis, bellows, a slide assembly.

16. An interface apparatus according to any of the preceding claims, further comprising a selectively demountable transport capsule, the capsule being configured to be mounted to the interface apparatus, such that the detector module may be moved inside the transport capsule and detached from each of the alignment member and guide mechanism so as to enable removal of the detector module from the instrument.

17. An interface apparatus according to claim 16, further comprising a second guide mechanism configured when in use to move the mounted detector module along a second guide path into the transport capsule.

18. An interface apparatus according to any of the preceding claims, further comprising an interface connector for providing, when in use, one or more electrical connections to a complementary module connector of the detector module, and wherein the said interface connector and detector module are together arranged so as to protect the detector module from damage caused by electrostatic discharge.

19. An interface apparatus according to any of the preceding claims, wherein the guide mechanism further comprises a service position along the transport path which is external to the instrument chamber, such that, when the detector module is positioned within the service position, a user may access a sensor head of the detector module.

20. An interface apparatus according to any of the preceding claims, wherein the guide mechanism is configured, when the sensor is not in use, to move the mounted detector module away from the first position.

21. An interface apparatus for a particle beam instrument, the interface apparatus comprising: an alignment member for causing a detector module of the particle beam instrument to be mounted to the interface apparatus in a predefined orientation; a guide mechanism configured when in use to move the mounted detector module along a guide path between a first position, within a chamber of the particle beam instrument, and a second position; and an adjustment mechanism configured to move the mounted detector module between the first position and a third position that is within the chamber.

22. A method of replacing a detector module in a particle beam instrument using an interface apparatus according to any of the preceding claims, the method comprising: a. Operating the guide mechanism to remove a first detector module from the particle beam instrument chamber; b. Detaching the first detector module from the guide mechanism; c. Attaching a second detector module to the guide mechanism and aligning the second detector module using the alignment member so as to achieve the predetermined alignment for the second detector module; and, d. Moving the second detector along the guide mechanism to place it in the first position for use.

23. A method according to claim 22, wherein the interface apparatus further comprises a selectively demountable transport capsule, the method further comprising: mounting the capsule to the interface apparatus, moving the first detector module inside the transport capsule, and detaching the first detector module from each of the alignment member and the guide mechanism so as to enable removal of the detector module from the instrument.

24. A method of replacing a sensor head of a detector module in a particle beam instrument using an interface apparatus according to claim 19, the method comprising: a. Operating the guide mechanism to remove a first detector module comprising a first sensor head from the particle beam instrument chamber and place it in the service position; b. Detaching the first sensor head from first detector module; c. Attaching a second sensor head to the first detector module; and, d. Moving the first detector module with the second sensor head along the guide mechanism to place it in the first position for use.

25. A method according to claim 24, wherein the second sensor head is provided with a selectively removable cover surrounding at least the sensor of the sensor head and wherein, during step (c), the cover remains surrounding the sensor whilst the sensor head is attached to the detector module and wherein step (c) further comprises removing the cover prior to step (d).

26. A method according to any of claims 22 to 25, wherein, prior to step (a) the detector module is packaged in a remote location including each of: a. the provision of thermal and electrical joints; and, b. a sensor of the detector module is aligned such that when the detector module is aligned with the alignment member of the interface apparatus, the detector module will be correctly aligned in the instrument when the detector module is in the first position.

27. A detector module adapted for use with an interface apparatus according claim 19, and comprising a selectively removable sensor head, the detector module being provided with a selectively removable cover surrounding at least a sensor of the sensor head.