Method for adjusting a laser beam sample analysis system

Abstract

Title: Method for Adjusting a Sample Analysis System by Laser Beam The invention relates to a method for adjusting a sample analysis system (1) by laser beam (3), comprising the steps of: emitting a laser beam (3), aligning the laser beam (3) on a theoretical axis (T), characterized in that the step of aligning the laser beam (3) comprises the substeps of: positioning a target (9) having a target marker (10) between a steerable mirror (7) and a receiving area (5), adjusting the orientation of the steerable mirror (7) to coincide the laser beam (3) with the target marker (10) of the target (9), by visual inspection. Figure for the abstract: Fig. 1

Description

Title of the invention: Method for adjusting a laser beam sample analysis system

[0001] The present invention relates to the field of high-resolution mapping and analysis of elements in solids.

[0002] More particularly, the invention relates, in particular but not exclusively, to a high-resolution analysis device for mapping elements in solids.

[0003] The invention can in particular be applied to the elemental analysis of hydrogen and oxygen by optical emission spectrometry on laser-produced plasma, in the field of the nuclear industry, or even the aeronautical or space industry.

[0004] In applications such as the characterization of devices subjected to radioactive sources, or the characterization of the aging ability of devices used in particularly severe environments, for example in aircraft or spacecraft, it may prove essential to carry out the elemental analysis of metallic samples.

[0005] More specifically, it may be necessary to be able to map these elements within the analyzed sample. By mapping, we mean an identification of the elements composing the analyzed sample and, possibly, the distribution and the relationship between the different elements.

[0006] Such an analysis can prove particularly useful in studies of hydrogen embrittlement of metals, or in studies of aging of fuel cladding in the presence of oxygen, or in studies of embrittlement of fuel cladding caused by the formation of hydrides, the latter promoting the propagation of cracks.

[0007] There are various known methods of mapping elements present in samples.

[0008] One of these methods is elemental analysis by optical emission spectrometry on laser-produced plasma, designated by the acronym "SEOPPL", a technique which is carried out in a natural atmosphere, also designated by the English acronym "LIBS" corresponding to the English expression "laser-induced breakdown spectroscopy"

[0009] This method is particularly applicable to the control and in situ characterization of samples of parts to be analyzed.

[0010] A method for elemental analysis by optical emission spectrometry on laser-produced plasma in the presence of argon is described in patent document published under number EP 0 654 663.

[0011] In practice, an analysis system is used to emit a laser beam onto a part to be analyzed. The laser beam is emitted by a laser source and then passes through various lenses and diaphragms before impacting the part to be analyzed.

[0012] The impact of the laser beam on the part to be analyzed generates the creation of a plasma as close as possible to which an optical fiber is positioned allowing the acquisition of an image which is analyzed by an ad hoc software allowing the determination of the elemental mapping of the material constituting the part to be analyzed, that is to say, to establish a precise identification of the constituent components of the material of the analyzed sample.

[0013] During use of the system, external parameters such as vibrations or even temperature can influence beam emission and reduce the quality of the analysis.

[0014] Indeed, temperature and / or vibrations can cause a displacement of the mirrors deflecting the laser beam emitted by the laser source.

[0015] The result is that the point of impact of the laser beam on the sample is not, or not entirely, located in a predetermined area, which prevents the correct analysis that is carried out.

[0016] It is therefore necessary to adjust the system to obtain a quality analysis.

[0017] Classically, such an adjustment is made empirically.

[0018] Indeed, to achieve this adjustment, a laser beam is emitted to impact a test sample so that the position of the impact on the sample is analyzed.

[0019] It is then possible to determine whether the beam is properly positioned or not.

[0020] Such a method of adjustment is long and tedious.

[0021] With this method, the adjustment is then carried out in an approximate manner, until the impact position on a sample is deemed satisfactory without the final optimal obtaining of the laser beam being guaranteed.

[0022] The invention aims in particular to overcome the disadvantages of the prior art.

[0023] More specifically, the invention aims to provide a method for adjusting the alignment of a laser beam that is more reliable than the prior art.

[0024] The invention also aims to provide such a method which is simpler and faster to implement than the prior art.

[0025] These objectives, as well as others which will appear subsequently, are achieved thanks to the invention which relates to a method of adjusting a system for analyzing a metallic sample by laser beam, the analysis system comprising: - a chassis having a receiving area for a sample to be analyzed; - a laser beam generation module, mounted on the chassis; - a swiveling mirror mounted on the chassis, allowing the reflection of the laser beam emitted by the generation module towards the receiving area; the process comprising the steps of: - emit a laser beam from the generation module, - align the laser beam on a theoretical axis, characterized in that the step of aligning the laser beam comprises the substeps of: - position a target with a reference mark between the orientable mirror and the receiving area, designed to coincide with the laser beam, - adjust the orientation of the swiveling mirror to make the laser beam coincide with the target mark on the target, by visual check.

[0026] Such a method allows the analysis system to be adjusted quickly and easily.

[0027] Indeed, the correct positioning of the adjustable mirror is ensured by a simple visual check. Therefore, the operator makes the adjustment with direct visual feedback, allowing them to react quickly without the need for specialized tools.

[0028] Furthermore, visual control is simplified by the fact that the target has a target mark since the operator knows that he has correctly adjusted the analysis system when he no longer sees the laser beam on the target, that is to say when the laser beam coincides with the target mark.

[0029] According to an advantageous aspect, the analysis system integrates a turret carrying at least two objectives, including an adjustable objective and a fixed objective, said fixed objective having a filter reception slot, the method being characterized in that it includes, prior to the step of positioning the target, a step of selecting said fixed objective, by manipulation of the turret, to position it on the path of the laser beam, the target being introduced into the filter reception slot.

[0030] This step allows the target to be positioned identically for each setting of the analysis system.

[0031] Furthermore, the use of the filter receiving slot allows the target to be used on a standard analysis system, without any particular modification or adaptation of said analysis system to the use of the target.

[0032] According to another advantageous aspect, the chassis carries a well extending along the theoretical axis and intended to be traversed by the laser beam, and the visual control of the step of adjusting the orientation of the steerable mirror is carried out by observation in said well.

[0033] The control is then carried out visually by the operator who can look through the well to check the orientation of the steerable mirror and its incidence on the displacement of the trajectory of the laser beam and act accordingly.

[0034] The invention also relates to a system for analyzing a metallic sample by laser beam, for implementing the process as previously described, the analysis system comprising: - a chassis with a receiving area for a sample to be analyzed; - a laser beam generation module, mounted on the chassis; - a swiveling mirror mounted on the chassis, allowing the reflection of the laser beam emitted by the generation module towards the receiving area; - means for adjusting the orientation of the steerable mirror, characterized in that the system also includes a target having a target marker intended to coincide with the laser beam and in that the chassis carries a target support, positioned between the steerable mirror and the receiving area, the target being intended to be positioned in the target support along a theoretical axis relative to the receiving area.

[0035] Such an analysis system makes it possible to adjust the trajectory of the laser beam in a simple and quick manner.

[0036] Indeed, the operator can directly control, without recourse to special technical means, the results of his action on the adjustment means.

[0037] In other words, the operator can, by simply observing the target, detect whether the trajectory followed by the laser beam is correct (in which case the operator does not perceive the laser beam on the target) or incorrect (in which case the operator perceives a mark on the target, a mark formed by the impact of the laser beam on the target).

[0038] According to an advantageous aspect, the target takes the form of a strip with a hole drilled through it, the strip being made of a material resistant to laser radiation.

[0039] The use of a material resistant to laser radiation makes it possible to limit, or even eliminate, the deterioration of the target by the laser beam.

[0040] In other words, by using a material resistant to laser radiation, the laser beam does not damage the target on contact.

[0041] The target can thus be used for several adjustments, without risk of distorting the adjustment by a modification of the target reference due to the laser beam for example.

[0042] According to another advantageous aspect, the system incorporates a turret carrying at least two lenses, including an adjustable lens and a fixed lens, said fixed lens having a filter receiving slot, said filter receiving slot forming the target support.

[0043] Using the filter receiving slot as a target support allows a fixed reference point to be maintained on the analysis system so that the position of the target is identical for each use.

[0044] According to another advantageous aspect, the turret has a plurality of adjustable objectives.

[0045] The use of several objectives makes it possible to improve the quality of the sample analysis.

[0046] According to another advantageous aspect, the chassis also carries a well intended to be traversed by the laser beam and extending along the theoretical axis, s and allowing visual control to ensure the orientation of the laser beam.

[0047] The well forms a fairing which extends around the laser beam so as to protect the operators from a possible reflection of the beam by an incorrect trajectory.

[0048] Furthermore, extending the well along the theoretical axis also allows verification of the correct alignment of the laser beam.

[0049] According to another advantageous aspect, the analysis system also includes at least one steerable mounted deflection mirror, positioned between the generation source and the steerable mirror, the analysis system also including secondary adjustment means designed to orient the or each deflection mirror and modify the path of the laser beam.

[0050] This allows the creation of two stages of modification of the trajectory of the laser beam, namely a first stage, called primary adjustment, formed by the deflection mirror(s), and a second stage, called precision stage, formed by the orientable mirror.

[0051] Other features and advantages of the invention will become more apparent from the following description of preferred embodiments of the invention, given by way of illustrative and non-limiting examples, and the accompanying drawings described below.

[0052] [Fig.1] Fig.1 is a schematic representation of an analysis system according to the invention, according to a first embodiment.

[0053] [Fig.2] Fig.2 is a schematic representation of a target of the system analysis according to the invention, according to a first embodiment.

[0054] [Fig. 3] Fig. 3 is a schematic representation of a target of the system analysis according to the invention, according to a second embodiment.

[0055] With reference to [Fig.1], a system for analyzing 1 a metallic sample 2 by laser beam 3 is illustrated.

[0056] Analysis system 1 comprises: - a chassis 4 having a receiving area 5 for a sample 2 to be analyzed; - a 6-generation module of a 3-laser beam; - a steerable mirror 7 mounted on the chassis 4, allowing the reflection of the laser beam 3 emitted by the generation module 6 towards the reception area 5; - means of adjusting 8 the orientation of the adjustable mirror 7.

[0057] The generation 6 module is mounted on chassis 4 in a fixed manner.

[0058] In other words, the generation 6 module is positioned on chassis 4 and cannot to be moved once it has been secured to chassis 4.

[0059] When emitted by the generation module 6, the laser beam 3 is reflected by the adjustable mirror 7 to be directed towards the receiving surface 5.

[0060] However, repeated use and changes in environmental conditions, such as temperature, humidity, or vibrations, can alter the orientation of the adjustable mirror 7 over time. This creates a deviation in the path of the laser beam 3 from a theoretical path, which can impair the quality of the analysis.

[0061] In other words, as the device is used and / or the surrounding conditions change, the orientation of the steerable mirror 7 can change and generate a deviation of the laser beam 3 which is then no longer correctly positioned.

[0062] To avoid this, the orientation of the adjustable mirror 7 can be changed using the adjustment means 8.

[0063] To facilitate the adjustment of the orientation of the steerable mirror 7 and thus allow the adjustment of the trajectory of the laser beam 3, the analysis system 1 also includes a target 9 having a target marker 10 intended to coincide with the laser beam 3.

[0064] The chassis 4 also carries a target support 11 9 positioned between the steerable mirror 7 and the receiving area 5.

[0065] The target 9 is thus intended to be positioned in the target 9 support 11, along a theoretical axis T relative to the reception area.

[0066] The theoretical axis T thus forms a portion of the theoretical trajectory intended to be followed by the laser beam 3.

[0067] With reference to figures 2 and 3, the target 9 takes the form of a strip bearing the target marker 10.

[0068] According to a first embodiment illustrated by [Fig. 2], the target marker 10 takes the form of a marking made on the strip. This marking notably includes a central cross 101.

[0069] In this case, the alignment of the laser beam 3 is correct when said laser beam 3 coincides with the central cross 101.

[0070] According to a second embodiment illustrated by [Fig.3], the target marker 10 is in the form of a hole through the slat.

[0071] In this case, the alignment of the laser beam 3 is correct when said laser beam 3 passes through the hole.

[0072] The lamella is made of a material resistant to laser radiation.

[0073] This ensures that, when adjusting the trajectory of the laser beam 3, i.e. when adjusting the orientation of the steerable mirror 7, the impact of the laser beam 3 on the slat does not cause its destruction.

[0074] In other words, thanks to the laser-resistant material, the laser beam 3 does not damage the target 9 during adjustment. The same target 9 can then be reused. for several settings of the analysis system 1.

[0075] With reference to [Fig.1], the analysis system 1 incorporates a turret 12 carrying at least two targets.

[0076] The turret 12 more specifically carries a fixed lens 13 at least one adjustable lens 14.

[0077] The turret 12 is rotationally mounted on the chassis 4 so as to allow selection of the objective to be used, namely the fixed objective 13 or one of the adjustable objectives 14.

[0078] As illustrated by [Fig.1], the fixed lens 13 has a filter reception slot 15.

[0079] The filter reception slot 15 is intended for receiving filters to filter certain light waves when using the analysis system 1.

[0080] In use, and as described below, the target 9 is intended to take place in the filter receiving slot 15.

[0081] The support 11 of target 9 is thus formed by the filter reception slot 15.

[0082] As illustrated by [Fig. 1], the chassis 4 also carries a well 16 intended to be traversed by the laser beam 3.

[0083] Well 16 extends along the theoretical axis T.

[0084] The well 16 allows visual control to ensure the orientation of the laser beam 3 such as described below.

[0085] The adjustment of the analysis system 1 just described is carried out by a process comprising the steps of: - emit a laser beam 3 by the generation module 6; - align the laser beam 3 on the theoretical axis T.

[0086] More specifically, the step of aligning the laser beam 3 comprises the substeps of: - Position the target 9, displaying the target marker 10, between the adjustable mirror 7 and the reception zone 5, - adjust the orientation of the swiveling mirror 7 to make the laser beam 3 coincide with the target mark 10 of the target 9 by visual check.

[0087] More specifically, the visual control of the step of adjusting the orientation of the steerable mirror 7 is carried out by direct observation in the well 16.

[0088] Direct observation makes it possible to verify that the laser beam 3 coincides with the target marker 10 of the target 9 so that it is correctly oriented.

[0089] If the trajectory of the laser beam 3 is not good, then the observer, for example a technician, notices it directly since the laser beam 3 is visible on the target 9. Indeed, the laser beam 3 then impacts the target 9 and generates a bright spot on the target 9.

[0090] The user can then, via the adjustment means 8, change the orientation of the mirror orientable 7 and thus position it to modify the trajectory of the laser beam 3 so that it coincides with the target reference frame 10 and is thus confused with the theoretical axis T.

[0091] Of course, prior to the step of positioning the target 9, the method includes a step of selecting the fixed objective 13 by manipulating the turret 12, to position the fixed objective 13 on the path of the laser beam 3.

[0092] The target 9 being introduced into the filter receiving slot 15 which forms the support 11 of target 9, it is then also directly positioned on the path of the laser beam 3 in order to allow the adjustment of the analysis system 1.

Claims

Demands

1. A method for adjusting a sample analysis system (1) using a laser beam (3), the analysis system (1) comprising: - a chassis (4) having a receiving area (5) for a sample (2) to be analyzed; - a laser beam generation module (6) (3), mounted on the chassis (4); - a steerable mirror (7) mounted on the chassis (4), allowing the reflection of the laser beam (3) emitted by the generation module (6) towards the receiving area (5); the process comprising the steps of: - emit a laser beam (3) by the generation module (6), - align the laser beam (3) on a theoretical axis (T), characterized in that the step of aligning the laser beam (3) comprises the substeps of: - position a target (9) with a target marker (10) between the orientable mirror (7) and the receiving area (5), - adjust the orientation of the adjustable mirror (7) to align the laser beam (3) with the target mark (10) on the target (9), by visual inspection, and in which the chassis (4) carries a well (16) extending along the theoretical axis (T) and intended to be traversed by the laser beam (3), characterized in that the visual control of the step of adjusting the orientation of the steerable mirror (7) is carried out by observation in said well (16).

2. A method according to claim 1, wherein the analysis system (1) incorporates a turret (12) carrying at least two objectives, including an adjustable objective (14) and a fixed objective (13), said fixed objective (13) having a slot (15) for receiving filters, the method being characterized in that it comprises, prior to the step of positioning the target (9), a step of selecting said fixed objective (13), by manipulating the turret (12), to position it on the laser beam trajectory (3), the target (9) being introduced into the filter receiving slot (15).

3. A laser beam analysis system (1) for a metallic sample (2) for carrying out the process according to any one of the preceding claims, the analysis system (1) comprising: - a frame (4) having a receiving area (5) for a sample (2) to be analyzed; - a laser beam generation module (6) mounted on the frame (4); - a steerable mirror (7) mounted on the frame (4), allowing the reflection of the laser beam (3) emitted by the generation module (6) towards the receiving area (5);- means for adjusting (8) the orientation of the steerable mirror (7), characterized in that the system also includes a target (9) having a target marker (10) intended to coincide with the laser beam (3) and in that the frame (4) carries a target support (11) (9), positioned between the steerable mirror (7) and the receiving area (5), the target (9) being intended to be positioned in the target support (11) (9) along a theoretical axis (T) relative to the receiving area (5), and in that the frame (4) also carries a well (16) intended to be traversed by the laser beam (3) and extending along the theoretical axis (T), and allowing visual control to ensure the orientation of the laser beam (3).

4. Analysis system (1) according to the preceding claim, characterized in that the target (9) takes the form of a slat presenting the target marker (10), the slat being made of a material resistant to laser radiation.

5. Analysis system (1) according to claim 4 or 5, characterized in that the system integrates a turret (12) carrying at least two objectives, including an adjustable objective (14) and a fixed objective (13), said fixed objective (13) having a slot (15) for receiving filters, said slot (15) for receiving filters forming the support (11) of target (9).

6. Analysis system (1) according to the preceding claim, characterized in that the turret (12) has a plurality of adjustable objectives.

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