Patent Description:
There are various techniques available for carrying out an analysis of elemental composition of a sample under study, whereas a class of such techniques relies on an analysis of the elemental composition of the sample based on characteristics of an optical emission invoked from a sample under study. Prominent examples of such techniques include laser induced breakdown spectroscopy (LIBS) and optical emission spectroscopy (OES), which are widely applied both in mobile analyzer instruments that are useable in various environments and in desktop (or benchtop) analyzer instruments that are applicable e.g. in laboratory conditions.

Such an analyzer instrument is typically provided with an excitation source for invoking an optical emission from a sample under study, an optical arrangement for focusing the excitation on the sample and for transferring the invoked optical emission to a spectral detector, and an analyzer for determining the elemental composition of the sample based on the optical emission captured at the spectral detector.

In this regard, light collection optics provided as part of the optical arrangement aims at transferring the optical emission to the spectral detector in a manner that enables analysis of the elemental composition in a robust, reliable and accurate manner and any improvements in the light collection optics that serves these purposes contributes towards providing an analyzer instrument of improved performance.

In related art,<NPL>describes a study of sampling geometry in context of LIBS and draws a conclusion that by collecting light from the edges of a light-emitting plasma cloud formed on a sample surface one can record spectra using an ungated detector (no time resolution) that resemble closely the spectra obtained from a gated detector providing time-resolved detection. This result has implications in the development of less expensive LIBS detection systems.

It is therefore an object of the present invention to provide an approach for light collection that facilitates robust, reliable and accurate elemental composition analysis based on optical emission invoked from a sample under study.

In the following a simplified summary of some embodiments of the present invention is provided in order to facilitate a basic understanding of the invention. The summary is not, however, an extensive overview of the invention.

In accordance with an example embodiment, a light collection arrangement for an analyzer apparatus for elemental composition analysis is provided, the light collection arrangement provided for transferring optical emission from a target position to a detector interface of a detector assembly, the light collection arrangement comprising: an optical subsystem and an optical fiber assembly for transferring light between its first end and its second end, wherein the optical subsystem is arranged to transfer the optical emission from the target position to the first end of the optical fiber assembly and wherein the second end of the optical fiber assembly is coupled to the detector interface, and wherein the second end of the optical fiber assembly comprises a second opaque mask arranged to cover the fiber core on the second end of the optical fiber assembly apart from a transparent slit that allows for the optical emission to exit the fiber core.

In accordance with another example embodiment of the invention, an analyzer instrument for elemental composition analysis is provided, the analyzer instrument comprising an optical assembly according to the example embodiment described in the foregoing arranged in a space within a portion of a housing of the analyzer instrument; and the detector assembly arranged to receive the optical emission via the detector interface and generate one or more measurement signals that are descriptive of the received optical emission.

The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.

<FIG> illustrates a block diagram of some logical elements of optical engine <NUM> according to an example together with some elements of an analyzer instrument <NUM> that is useable for analysis of elemental composition of a sample using optical emission spectroscopy via application of the optical engine <NUM>, whereas <FIG> schematically illustrates some aspects of the optical engine <NUM> according to an example together with some elements of the analyzer instrument <NUM> and with a sample <NUM>. The optical engine <NUM> may be alternatively referred to as an optical assembly. Nevertheless, in the following examples this entity is predominantly referred to as the optical engine <NUM>.

The optical engine <NUM> may comprise an exciter <NUM> for generating an excitation in order to invoke a plasma plume on a surface of the sample <NUM> and an optical arrangement <NUM> for transferring the excitation emitted from the exciter <NUM> to a target position 130a on the sample <NUM> and for transferring an optical emission from the plasma plume invoked on the surface of the sample <NUM> (from the target position 130a) to a detector assembly <NUM>. The elements of the analyzer instrument <NUM> shown in <FIG> and/or <FIG> include the detector assembly <NUM> for generating one or more measurement signals that are descriptive of optical emission received therein and a controller <NUM> for controlling at least some aspects of operation of the exciter <NUM> and the detector assembly <NUM> and for carrying out analysis of elemental composition of the sample <NUM> based on the one or more measurement signals generated in the detector assembly <NUM>.

The optical engine <NUM> may be applicable, for example, for optical analysis techniques such as LIBS and OES described in the foregoing and, consequently, the analyzer instrument <NUM> making use of the optical engine may be a LIBS analyzer or an OES analyzer, respectively. The analyzer instrument may be a mobile analyzer instrument or a stationary analyzer instrument: examples of the former include handheld analyzer instrument and (otherwise) portable analyzer instruments intended for outdoor or indoor use in field conditions, whereas examples of the latter include benchtop (or desktop) analyzer instruments intended primarily for indoor use in laboratory or factory conditions. The elements of the optical engine <NUM> may be arranged in a space within a housing of the analyzer instrument <NUM> such that the excitation from the exciter <NUM> is directed and/or focused at the target position 130a and that the detector assembly <NUM> is able to receive the emission originating from the sample <NUM>. In this regard, the sample <NUM> and target position 130a are located outside the housing of the analyzer instrument, whereas the space containing the elements of the measurement assembly <NUM> is located within the housing in a location that can be conveniently brought into immediate vicinity of the sample <NUM> to bring a surface of the sample <NUM> at the target position 130a or, conversely, the space containing the elements of the measurement assembly <NUM> may be positioned in the housing such that the sample <NUM> can be conveniently brought into immediate vicinity thereof to bring the surface of the sample <NUM> at the target position 130a.

Each of the exciter <NUM>, the detector assembly <NUM> and the controller <NUM> may be provided using respective techniques known in the art and hence they are not described in detail in the present disclosure. However, for completeness of the description, in the following a few non-limiting examples of providing each of the exciter <NUM>, the detector assembly <NUM> and the controller <NUM> are described at a high level, whereas further details concerning their characteristics and operation are provided in context of examples that pertain to the optical arrangement <NUM> to extent such details are necessary for understanding advantageous characteristics of the optical arrangement <NUM>.

The exciter <NUM> may be arranged to operate under control of the controller <NUM>, e.g. based on an activation signal issued by the controller <NUM>. The exciter <NUM> may comprise, for example, a light source that is arranged to generate excitation that comprises a light beam, a single light pulse or a series of two or more light pulses. Various characteristics of the excitation may be predefined ones and/or they may be defined in the activation signal. In an example, the exciter <NUM> may comprise a laser source arranged for emitting laser pulses. In such a scenario, the analyzer instrument <NUM> may be referred to as a laser-induced breakdown spectroscopy (LIBS) analyzer.

The detector assembly <NUM> may comprise a spectrometer for dispersing the optical emission into a set of wavelengths and a detector for generating, based on the dispersed optical emission received thereat, the one or more measurement signals that are descriptive of relative light intensities of the optical emission at different wavelengths, which may appear e.g. as one or more emission peaks at respective wavelengths. The optical emission may be input to the detector assembly <NUM> via a detector interface 106a, which may comprise, for example, an entrance slit of the spectrometer. The detector may comprise, for example, an image sensor provided as a charge-coupled device (CCD), as a complementary metal-oxide-semiconductor (CMOS) sensor or, in general, as any (silicon-based) solid state sensor, thereby substantially capturing one or more images that represent the dispersed optical emission originating from the plasma plume invoked on the surface of the sample <NUM>. <FIG> further depicts an optical fiber assembly <NUM> for transferring the optical emission to the detector assembly <NUM> via the detector interface 106a. Various characteristics of the optical fiber assembly <NUM> are described via non-limiting examples provided in the following.

The controller <NUM> may be provided, for example, by an apparatus that comprises a processor and a memory, where the memory is arranged to store computer program code that, when executed by the processor, causes the apparatus to operate as the controller <NUM> according to the present disclosure. Such an apparatus may be referred to as a computing apparatus. A more detailed example of providing the controller <NUM> via usage of such a computing apparatus is provided in the following with references to <FIG>. As a particular example of its operation, the controller <NUM> may be arranged to carry out a measurement procedure in response to a trigger signal, where the trigger signal may be received, for example, in response to the user operating a user interface (Ul) of the analyzer instrument <NUM> accordingly. The controller <NUM> may further operate to display a measurement result obtained from the measurement procedure via the UI of the analyzer instrument <NUM>, to store the measurement result in a memory provided in the analyzer instrument <NUM> and/or to transmit the measurement result to another device via usage of a communication apparatus available in the analyzer instrument <NUM>, where the communication apparatus may enable wired and/or wireless communication between the analyzer instrument <NUM> and the other device.

The measurement procedure may be carried out in order to determine at least some aspects of elemental composition of the sample <NUM> under study and it may comprise the controller <NUM> operating the exciter <NUM> to generate the excitation in order to invoke the plasma plume on the surface of the sample <NUM> and, consequently, the optical emission from the sample <NUM>, the controller <NUM> recording the one or more measurement signals generated by the detector assembly <NUM> based on the optical emission from the sample <NUM>, and the controller <NUM> carrying out the analysis of elemental composition of the sample <NUM> based on the one or more measurement signals. The measurement result obtained from the measurement procedure may comprise information that defines one or more elements included in the sample <NUM> and the measurement result may further comprise information on the relative concentrations of the one or more elements in the sample <NUM>. Such measurement procedures carried out via operation of the analyzer instrument <NUM> in the framework of techniques such as the LIBS and OES referred to above are well known in the art and they are not described in further detail in the present disclosure.

Along the lines described in the foregoing, <FIG> schematically illustrates some elements of the optical engine <NUM> in further detail together with some further elements of the analyzer instrument <NUM> and with the sample <NUM>. In particular, the illustration of <FIG> schematically depicts a light collecting mirror <NUM>, a beam splitting mirror <NUM>, a focusing mirror <NUM> and the optical fiber assembly <NUM>, which may be considered as respective components of a light collection arrangement 104a. The light collecting mirror <NUM>, the beam splitting mirror <NUM>, the focusing mirror <NUM> and a first end 110a of the optical fiber assembly <NUM> may be arranged in the space dedicated therefor within the housing of the analyzer instrument <NUM> (as described in the foregoing), whereas a second end 110b of the optical fiber assembly <NUM> may be coupled to the detector interface 106a. The first end 110a serves as an input face of the optical fiber assembly <NUM>, whereas the second end 110b serves as an output face of the optical fiber assembly <NUM>.

The exciter <NUM> may be positioned in said space within the housing of the analyzer instrument <NUM> such that it is able to emit the excitation therefrom towards the target position 130a that is outside said space and outside the analyzer instrument <NUM>. In this regard, said space may include an opening through which the excitation is able to exit said space and the optical emission invoked from the sample <NUM> is able to enter said space. The opening in said space may be closed by a sample window <NUM>, which is able to transmit the excitation originating from the exciter <NUM> and the optical emission invoked from the sample <NUM> while it may close the space containing the optical engine <NUM> in order to prevent moisture, dirt, dust etc. from exterior of the housing from entering the space.

The light collecting mirror <NUM> and the focusing mirror <NUM> may be positioned and oriented with respect to each other and with respect to the first end 110a of the optical fiber assembly <NUM> such that the optical emission invoked on the sample <NUM> is transferred from the target position 130a via the light collecting mirror <NUM> and the focusing mirror <NUM> to the first end 110a of the optical fiber assembly <NUM>: the light collecting mirror <NUM> may comprise a collimating mirror arranged to reflect the optical emission originating from the target position 130a as a collimated light beam towards the focusing mirror <NUM>, which may be arranged to reflect the collimated light beam received from the light collecting mirror <NUM> towards the first end 110a of the optical fiber assembly <NUM> such that light beam is substantially focused at the first end 110a of the optical fiber assembly <NUM>, thereby providing a real image of the plasma plume at first end 110a.

The excitation may be transferred from the exciter <NUM> towards the target position 130a via the beam splitting mirror <NUM> and the light collecting mirror <NUM>, where the beam splitting mirror <NUM> may be arranged between the light collecting mirror <NUM> and the focusing mirror <NUM> in an oblique angle (e.g. in a <NUM>-degree angle) with respect the optical axis between the light collecting mirror <NUM> and the focusing mirror <NUM>. In this regard the beam splitting mirror may be provided as a dichroic mirror that reflects wavelengths at an around the wavelength applied for the excitation (e.g. laser light at wavelength of <NUM>) while it passes through wavelengths considered by the detector assembly <NUM> (e.g. a predefined spectral range between <NUM> and <NUM>). In an example, the optical arrangement <NUM> may further comprise a focusing lens that in combination with the light collecting mirror <NUM> serves to focus the excitation at the target position 130a, where the focusing lens may be arranged in a propagation path of the excitation between the exciter <NUM> and the beam splitting mirror <NUM>. In a further example, the exciter <NUM> may be provided with an integrated focusing lens or a focusing assembly of other kind for focusing the excitation at the target position 130a may be applied.

The light collecting mirror <NUM>, the beam splitting mirror <NUM> and the focusing mirror <NUM> serve as a non-limiting example of optical components that may serve as an optical subsystem that is applied for transferring the optical emission from the target position 130a to the first end 110a of the optical fiber assembly <NUM>, whereas in other examples a different optical subsystem may be applied instead without departing from the scope of the present disclosure. As an example in this regard, such an optical subsystem may comprise one or more optical components, such as one or more mirrors and/or one or more lenses. Along similar lines, the arrangement of the exciter <NUM> with respect to components of the optical engine <NUM> and/or the manner of transferring the excitation therefrom towards the target point 130a serves as a non-limiting example and a different arrangement for transferring the excitation to the target position 130a may be applied without departing from the scope of the present disclosure. In particular, the transfer of excitation from the exciter to the target position 130a may be provided via an arrangement that does not involve the beam splitting mirror <NUM> arranged in the optical path between the light collecting mirror <NUM> and the focusing mirror <NUM>.

Yet further, the example illustrated in <FIG> is a schematic one that serves the purpose of conceptual illustration and hence the respective shapes, sizes and/or relative positions of the elements of the optical engine <NUM> shown in the illustration of <FIG> may not reflect the shapes sizes and/or relative positions of the respective elements of a real-life implementation of the optical engine <NUM>. In particular, the position of the first end 110a of the optical fiber assembly <NUM> with respect to the respective positions of the other components of the optical engine <NUM> and/or the light collection arrangement 104a may be different from that shown in the example of <FIG> and it may be selected in view of respective positions and characteristics of other components of the optical engine <NUM> and/or the light collection arrangement 104a as well as in view of the design and requirements of the analyzer instrument <NUM> making use of the optical engine <NUM>.

The optical fiber assembly <NUM> may comprise a cladding <NUM> and a fiber core <NUM> that runs between the first end 110a and the second end 110b of the optical fiber assembly <NUM> within the cladding <NUM>, as schematically illustrated in <FIG>. Herein, the term cladding <NUM> is to be construed broadly, encompassing all those layers of the optical fiber assembly <NUM> that surround the fiber core <NUM> but that do not serve to transfer light between the first end 110a and the second end 110b of the optical fiber assembly <NUM>. In an example, the fiber core <NUM> may have a substantially circular cross-section having a diameter in a range from <NUM> to <NUM> micrometers (µm).

<FIG> schematically illustrates some aspects of the optical fiber assembly <NUM> according to an example outside the scope of the present invention. In this example, the first end 110a of the optical fiber assembly <NUM> may be provided with a first opaque mask <NUM> that covers a central portion of the fiber core <NUM>, whereas in the second end 110b the fiber core <NUM> may be substantially fully exposed for coupling to the detector interface 106a. The first opaque mask <NUM> may serve to prevent a portion of the optical emission that originates from a central portion of the plasma plume from entering the fiber core <NUM> while it may allow a portion of the optical emission that originates from a peripheral portion of the plasma plume to enter the fiber core <NUM>. In one example, the first opaque mask <NUM> may comprise a masking element attached on the surface of the first end 110a of the optical fiber assembly <NUM>, whereas in another example the first opaque mask <NUM> may comprise a masking layer deposited on the surface of the first end 110a of the optical fiber assembly <NUM>, where the masking layer may be provided e.g. as a thin film deposited metal such aluminum, chromium, gold, etc..

In a further example, the first opaque mask <NUM> may be provided via arranging a first covering portion that has an opaque central portion surrounded by a transparent portion to cover the first end 110a of the optical fiber assembly <NUM>, the opaque portion thereby serving as the first opaque mask <NUM>. The opaque center portion of the first covering portion may be provided, for example, via attaching a masking element or via depositing a masking layer on a transparent covering portion. In one example, the first covering portion may be attached on the first end 110a in a fixed manner, whereas in another example the first covering portion may be detachably attached on the first end 110a. In a non-limiting example, the first covering portion may be provided as a cap that may be mounted on the first end 110a of the optical fiber assembly <NUM> in fixed or detachable manner. In a yet further example, the first opaque mask <NUM> may be provided as an element of the light collection arrangement 104a that is separate from the optical fiber assembly <NUM> and disposed substantially to a focal point of the focusing mirror <NUM>, thereby arranging the first opaque mask <NUM> against the first end 110a of the optical fiber assembly <NUM> when the optical fiber assembly <NUM> is mounted into its position to receive the focused light beam from the focusing mirror <NUM>.

Along the lines described in the foregoing, the optical subsystem (e.g. the arrangement of the light collecting mirror <NUM> and the focusing mirror <NUM>) may be arranged to focus the optical emission at the first end 110a of the optical fiber assembly <NUM> and, conversely, the first end 110a of the optical fiber assembly <NUM> may be arranged to receive the focused optical emission. Moreover, the optical emission may be transmitted via the fiber core <NUM> to the second end 110b of the optical fiber assembly <NUM>, which may be coupled to the spectrometer of the detector assembly <NUM> via the detector interface 106a e.g. via the entrance slit of the spectrometer. The first opaque mask <NUM> may serve to block the portion of the optical emission that originates from a central portion of the plasma plume invoked by the excitation on the surface of the sample <NUM> from entering the fiber core <NUM> while allowing the portion of the optical emission that originates from peripheral portion(s) of the plasma plume to enter the fiber core <NUM>, thereby transferring (only) the optical emission originating from the peripheral portion(s) of the plasma plume to the spectrometer in the detector assembly <NUM>.

In this regard, the plasma plume is hottest in its center portion, whereas the temperature gradually decreases toward peripheral portions of the plasma plume. Typically, the optical emission from the hottest part(s) of the plasma plume in its central portion would result in capturing relatively broad emission peaks in the one or more measurement signals, which may result in compromised accuracy and/or reliability of the elemental component analysis carried out in the controller <NUM>, whereas the optical emission from cooler parts of the plasma plume around its central portion enable capturing narrower emission peaks in the one or more measurement signals, which typically allows for improved accuracy and/or reliability of the elemental composition analysis. In this regard, the first opaque mask <NUM> arranged to cover the central portion of the fiber core <NUM> at the first end 110a of the optical fiber assembly <NUM> may serve to block a portion of the optical emission originating from the hottest part(s) of the plasma plume, thereby passing through only those portion(s) of the optical emission that enable capturing relatively narrow emission peaks in the one or more measurement signals in order to facilitate analysis of elemental composition of the sample <NUM> at improved accuracy and/or reliability.

In the example of <FIG> the cross-section of the fiber core <NUM> and the first opaque mask <NUM> arranged thereon are depicted as respective substantially circular entities arranged for conveying a substantially circular image of the plasma plume invoked on the sample <NUM>. This is, however, a non-limiting example and in other examples the cross-section of the fiber core <NUM> and/or the first opaque mask <NUM> may have a respective shape that is different from a substantially circular shape (e.g. elliptical) for example to account for a light collection arrangement where the image of the plasma plume received at the first end 110a of the optical fiber assembly <NUM> is non-circular e.g. due to capturing the optical emission at a non-right angle with respect to the surface of the sample <NUM>.

The size of the first opaque mask <NUM> may depend on factors such as characteristics of the exciter <NUM> (in terms of the expected size of the plasma plume it serves to invoke on the surface of the sample <NUM>), characteristics of the optical components applied for transferring the image of the plasma plume from the target position 130a to the first end 110a of the optical fiber assembly <NUM> (e.g. in terms of magnification of the image) and/or on the size (e.g. the diameter) of the image of the plasma plume on the fiber core <NUM> at the first end 110a of the optical fiber assembly <NUM>. As a non-limiting example, the first opaque mask <NUM> may be applied to cover approximately <NUM> to <NUM> %, e.g. <NUM> %, of the cross-sectional area of the fiber core <NUM> to ensure sufficient portion of the optical emission entering the fiber core <NUM> while ensuring that the portion of the optical emission originating from the hottest part(s) at the center portion of the plasma plume is prevented from entering the fiber core <NUM>. However, along the lines described above, the most expedient size of the first opaque mask <NUM> depends on the size of the image of the plasma plume projected on the first end 110a of the optical fiber assembly <NUM> in relation to the desired extent of the emission-peak-narrowing effect arising from blocking the optical emission from the hottest part(s) of the plasma plume in its central portion.

<FIG> schematically illustrates some aspects of the optical fiber assembly <NUM> according to another example. In this example, the fiber core <NUM> in the first end 110a of the optical fiber assembly <NUM> may be substantially fully exposed for reception of the optical emission via the optical subsystem (e.g. via the arrangement of the light collecting mirror <NUM> and the focusing mirror <NUM>), whereas the second end 110b of the optical fiber assembly <NUM> may be provided with a second opaque mask <NUM> arranged to cover the fiber core <NUM> on the second end 110b apart from a slit <NUM> that is transparent and hence allows for the optical emission to exit the fiber core <NUM>. As a non-limiting example, the width of the slit <NUM> may be in a range from <NUM> to <NUM> micrometers, e.g. <NUM> micrometers. The slit <NUM> may extend substantially from an edge of the fiber core <NUM> to an opposite edge of the fiber core <NUM> and it may have a substantially uniform width, whereas the slit <NUM> may have an overall shape of a substantially straight 'line' (as in the illustration of <FIG>) or it may have a curved overall shape. Hence, at least conceptually, the slit <NUM> may be provided as an opening in the second opaque mask <NUM> that otherwise covers the fiber core <NUM> at the second end 110b of the optical fiber assembly <NUM> or as an opening between two mask portions that jointly serve as the second opaque mask <NUM>.

The second opaque mask <NUM> may be provided using any of the techniques described in the foregoing for providing the first opaque mask <NUM>: in one example, the second opaque mask <NUM> may comprise a masking element attached on the surface of the second end 110b of the optical fiber assembly <NUM>, whereas in another example, the second opaque mask <NUM> may comprise a masking layer deposited on the surface of the second end 110b of the optical fiber assembly <NUM> (e.g. as described in the foregoing for the masking layer deposited on the first 110a, mutatis mutandis). In a further example, the second opaque mask <NUM> may be provided via arranging a second covering portion that is opaque apart from a transparent opening of a type described above to provide the slit <NUM>, the second covering portion thereby serving as the second opaque mask <NUM>. The opaque portion of the second covering portion may be provided, for example, via attaching one or more masking elements or via depositing one or more masking layer portions on a transparent second covering portion. In one example, the second covering portion may be attached on the second end 110b in a fixed manner, whereas in another example the second covering portion may be detachably attached on the second end 110b. In a non-limiting example, the second covering portion may be provided as a cap that may be mounted on the second end 110b of the optical fiber assembly <NUM> in fixed or detachable manner.

When using the optical fiber assembly <NUM> according to the example of <FIG> having the slit provided at the second end 110b of the optical fiber assembly <NUM>, the detector interface 106a may be provided without the entrance slit that is already provided at the second end 110b of the optical fiber assembly <NUM>. While this simplifies the structure of the detector assembly <NUM> and/or the detector interface 106a via requiring only an interface for receiving (an optical fiber receptacle provided for coupling) the second end 110b of the optical fiber assembly <NUM> instead of having the entrance slit prepared therein (e.g. via application of laser cutting or a corresponding technique), it imposes an additional requirement for the optical fiber assembly <NUM> via preparation of the second opaque mask <NUM> described above to provide the slit <NUM>. However, techniques available for preparing the second opaque mask <NUM> and the slit <NUM> on the second end 110b of the optical fiber assembly <NUM> (in comparison to those available for preparing the entrance slit into the detector assembly <NUM>) enable more accurate design of the slit <NUM> in terms of its width and its position with respect to the fiber core <NUM>, thereby enabling reduced engineering tolerance in preparation of the slit <NUM>. In such a design, coupling of the second end 110b of the optical fiber assembly <NUM> to the detector assembly <NUM> via the detector interface 106a (e.g. via usage of the optical fiber connector provided for coupling the second end 110b to the detector interface 106a) may be provided with a mechanism that prevents rotary motion of the fiber core <NUM> with respect to the detector interface 106a and/or to detector assembly <NUM> to ensure keeping the slit <NUM> in alignment with the spectrometer in the detector assembly <NUM>.

<FIG> schematically illustrates some aspects of the optical fiber assembly <NUM> according to a further example. In this example, the first end 110a of the optical fiber assembly <NUM> may be provided with the first opaque mask <NUM> that covers a central portion of the fiber core <NUM> (as in the example of <FIG>), whereas the second end 110b of the optical fiber assembly <NUM> may be provided with the second opaque mask <NUM> arranged to cover the fiber core <NUM> on the second end 110b apart from the transparent slit <NUM> (as in the example of <FIG>). Hence, the optical fiber assembly <NUM> according to this example provides the respective advantages of the examples described in the foregoing with references to <FIG>.

Still referring to the example of <FIG>, the respective back sides of the first opaque mask <NUM> and the second opaque mask <NUM>, i.e. their respective sides that are facing the fiber core <NUM>, may comprise or may be provided as respective reflecting surfaces. Consequently, while a portion of the optical emission arriving via the fiber core <NUM> at the second end 110b of the optical fiber assembly <NUM> may exit the fiber core <NUM> through the slit <NUM>, another portion of the optical emission may be reflected back towards the first end 110a of the optical fiber assembly <NUM> by the reflecting back side of the second opaque mask <NUM>. Moreover, a portion of the optical emission arriving via the fiber core <NUM> at the first end 110a of the optical fiber assembly <NUM> may exit the fiber core <NUM> through portion(s) that are not covered by the first opaque mask <NUM>, whereas another portion of the optical emission may be reflected back towards the second end 110b of the optical fiber assembly <NUM> by the reflecting back side of the first opaque mask <NUM>. Consequently, due to the respective reflecting back sides of the first and second opaque masks <NUM>, <NUM> part of the optical emission originating from the target position 130a may be transferred via the optical fiber assembly <NUM> to the detector interface 106a after one or more round-trips between the second and first ends 110b, 110a of the optical fiber assembly <NUM>, thereby enabling improved transmission of the optical emission from the target position 130a to the detector input 106a.

In a yet further example, the optical fiber assembly <NUM> may be similar to that described in context of examples that refer to <FIG> with the back side of the first opaque mask <NUM> comprising or otherwise being provided as a reflecting surface. Moreover, the detector interface 106a may comprise the entrance slit described in the foregoing that has its surrounding area provided as a reflecting surface. Consequently, when the second end 110b of the optical fiber assembly <NUM> is coupled to the detector interface 106a (with a substantially negligible gap between the second end 110b and the entrance slit of the detector interface 106a), the reflecting surface around the entrance slit serves the same purpose as the reflecting back surface of the second opaque mask <NUM> in the example of <FIG>, thereby enabling improved transmission of the optical emission from the target position 130a to the detector input 106a.

Referring back to the example of <FIG>, the controller <NUM> may be provided by a respective hardware means, by a respective software means or by a respective combination of a hardware means and a software means. As an example in this regard, <FIG> schematically depicts some components of an apparatus <NUM> that may be employed to implement the controller <NUM>. The apparatus <NUM> comprises a processor <NUM> and a memory <NUM>. The memory <NUM> may store data and computer program code <NUM>. The apparatus <NUM> may further comprise communication means <NUM> for wired or wireless communication with other apparatuses and/or user I/O (input/output) components <NUM> that may be arranged, together with the processor <NUM> and a portion of the computer program code <NUM>, to provide the UI of the analyzer instrument for receiving input from a user and/or for providing output to the user. In particular, the user I/O components may include user input means, such as one or more keys or buttons, a keyboard, a touchscreen or a touchpad, etc. The user I/O components may include output means, such as a display or a touchscreen. The components of the apparatus <NUM> are communicatively coupled to each other via a bus <NUM> that enables transfer of data and control information between the components.

The memory <NUM> and a portion of the computer program code <NUM> stored therein may be further arranged, with the processor <NUM>, to provide the controller <NUM>. Although the processor <NUM> is depicted as a respective single component, it may be implemented as respective one or more separate processing components. Similarly, although the memory <NUM> is depicted as a respective single component, it may be implemented as respective one or more separate components, some or all of which may be integrated/removable and/or may provide permanent / semi-permanent/ dynamic/cached storage.

The computer program code <NUM> may comprise computer-executable instructions that implement at least some functions of the controller <NUM> when loaded into the processor <NUM>. As an example, the computer program code <NUM> may include a computer program consisting of one or more sequences of one or more instructions. The processor <NUM> is able to load and execute the computer program by reading the one or more sequences of one or more instructions included therein from the memory <NUM>. The one or more sequences of one or more instructions may be configured to, when executed by the processor <NUM>, cause the apparatus <NUM> to operate as the controller <NUM> e.g. according to operations, procedures and/or functions described in the foregoing. Hence, the apparatus <NUM> may comprise at least one processor <NUM> and at least one memory <NUM> including the computer program code <NUM> for one or more programs, the at least one memory <NUM> and the computer program code <NUM> configured to, with the at least one processor <NUM>, cause the apparatus <NUM> to operate as the controller <NUM> e.g. in accordance with operations, procedures and/or functions described in the foregoing.

The computer program code <NUM> may be provided e.g. as a computer program product comprising at least one computer-readable non-transitory medium having the computer program code <NUM> stored thereon, which computer program code <NUM>, when executed by the processor <NUM> causes the apparatus <NUM> to operate as the analyzer controller <NUM> e.g. according to operations, procedures and/or functions described in the foregoing. The computer-readable non-transitory medium may comprise a memory device or a record medium that tangibly embodies the computer program. As another example, the computer program may be provided as a signal configured to reliably transfer the computer program.

Claim 1:
A light collection arrangement (104a) for an analyzer apparatus (<NUM>) for analysis of elemental composition of a sample (<NUM>) using optical emission spectroscopy, the light collection arrangement (104a) provided for transferring optical emission from a target position (130a) to a detector interface (106a) of a detector assembly (<NUM>), the light collection arrangement (104a) comprising:
an optical subsystem and an optical fiber assembly (<NUM>) for transferring light between its first end (110a) and its second end (110b),
wherein the optical subsystem is arranged to transfer the optical emission from the target position (130a) to the first end (110a) of the optical fiber assembly (<NUM>) and wherein the second end (110b) of the optical fiber assembly (<NUM>) is coupled to the detector interface (106a),
characterized in that the second end (110b) of the optical fiber assembly (<NUM>) comprises a second opaque mask (<NUM>) arranged to cover the fiber core (<NUM>) on the second end (110b) of the optical fiber assembly (<NUM>) apart from a transparent slit (<NUM>) that allows for the optical emission to exit the fiber core (<NUM>).