SU1121606A1 - Interference method of determination of difference of reactive indices and interference refractometer for application thereof (its versions) - Google Patents

Abstract

1. Interference method for determining the difference in refractive indices by passing a light beam through a differential prismatic cell with the test media and subsequent analysis of the resulting interference pattern, characterized in that, in order to improve the measurement accuracy, the original light beam is pre-split into two beams offset relative to each other and direct them to the refracting boundary a 9 of the section of the studied media in the differential prismatic cell at equal angles (L angles, and awns refractive index difference is judged by hodainterferiruk Tsikh beams defined by the analysis interferatsionnoy picture.

Description

2, Interferometric refractometer, containing an interferometer installed in it along the light beam of the differentiated prismatic cell, an interference pattern recording unit, which, for the purpose of increasing 1 and the accuracy and reproducibility of measurements, is a differential prismatic cuvette connected to an additional differential prismatic cuvette, in which the interface between the cavities for the studied media is parallel to the working faces of both cuvettes; the working faces of both cuvettes are located in the same points The plane and in front of the cuvettes are installed the splitting node of the initial beam into two parallel and displacements relative to each other of the beam, passing through the indicated cuvettes, and the block for recording the interference pattern contains a node comparing the difference in the paths of the interfering beams.

3. Interference refractometer of the contents of an interferometer with a differential prismatic cell installed in it along the beam of light., Interference pattern recording unit; The reason is that with the aim of accuracy and reproducibility of measurements 5, the differential prismatic cuvette is connected to an additional discharger of the prize by a magic cuvette so that the workers are grated in the single cuvette and the same planes of each cuvette, at least one refracting section of cavities for the test media is indicated, with the indicated divisions of the section of the separated cuvette being made up of their cavity; lell-chi working faces;

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If the cavities are q, 1 of the studied media and their interfaces are located in the same sequence along the beams, -; tju-iHaKOBoro mark, if the cavities of the DPP of the studied media and their interfaces are located in the opposite sequence along the beams, and in front of the cuvette there is a split node of the original beam into two parallel and mixed relate each other through the specified In this case, the block for detecting the interference pattern 1 contains a node comparing the differences in the course of the interfering beams.

4. The imperfect refractor; matching interferometer with a differential prismatic cell installed along the beam of light, an interference pattern recording unit that differs from that, in order to increase either the accuracy or the dynamic range of measurements, the differential prismatic cell of the r: typipen p.r is more at least with one additional differential prismatic cuvette, that the working faces of the cuvette are located in the same and the same planes, with B different cuvee mhx refracting the edges ;; of the section n (; the bones d; 1 of the studied media) are placed from the plane; the corners are different angles in absolute height; the splitting unit of the outgoing beam into two pairs of pleated and cm1 Xin X is located in front of the cuvettes, Others pass through the KiururTJ.i. through yjcaiiaHiiiiie, and the nnthe registration unit;) i) the ereitsioinoy picture with / de;) life1 ri3M: iveiHn rgtznogti: c. nv4Koii,

The invention of - (ssitsi and terferentsionnon refractometry and; .1 can be unsupervised (-; honest to high-quality .111gp-: from different media;; - by the method of parity show:; the method of differentiation of the chapartitee chapters; A) ht; -m transmittance of emission beams of light through a differential transmission device) with research; g / em media; subsequent rss ana.,; 1G5y formed and m (; rfs: mi - and ;; sig1 (| st chart nm P,

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However, this method does not provide a sufficiently high measurement accuracy for some applications, for example, for determining small differences in refractive indices in liquid microcolumn chromatography of bioorganic objects.

Closest to the present invention is a method implemented in an 2J interference refractometer. Using this device, the determination of the difference in refractive indices is carried out by passing a beam of light through a differential prismatic cell with the test media and subsequent analysis of the resulting interference pattern. At the same time, the light beams are directed at the refractive interfaces of the media at equal angles equal in absolute magnitude but opposite in sign. Therefore, the angle between the beams of light before they pass through the cuvette differs from the angle between the beams after they pass the cuvette by an amount proportional to the difference in refractive indices of the compared media. This circumstance leads to a change in the bandwidth in the observed interference pattern. Measuring the width of the interference band makes it possible to judge about n compared media.

However, the known method does not provide a sufficiently high measurement accuracy. The low accuracy is due to two factors: a significantly non-linear connection between the measured parameter (wide band) and the desired dn, and the low sensitivity of the measurements of the width of the interference band (usually not better than 10 A). In this connection, for a cuvette of 1-10 mm in size, the minimum error of determining U p is A. 10-10 and increases in proportion to the value of U u. The disadvantage of this method is that the measurement range has a gap in the range of those values dp at which the width of the interference band is larger than the aperture of the system and, therefore, cannot be measured.

The purpose of the invention is to improve the accuracy of measuring the difference in refractive indices.

The goal is achieved by the fact that according to the interference

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The method of determining the difference in refractive indices by passing a light beam through a differential prismatic cell with the test media and subsequent analysis of the inverting interference pattern, the original light beam is pre-split into two biased relative to each other beam and direct them to the refractive boundary of the test media in the differential prismatic cuvette at equal angles, and the difference in the refractive indices is judged by the path spacing of the interfering beams, determined by my analysis of the interference pattern.

To implement the method, three variants of an interference refractometer were proposed.

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According to the first embodiment, in order to improve the accuracy and reproducibility of measurements in a known refractometer containing an interferometer

5 with the differential prismatic cuvette installed along the light beam, as well as the interference pattern recording unit, the differential prismatic cuvette is connected to an additional differential prismatic cuvette, in which the interface between the cavities for the studied media is parallel to the working faces of both cuvettes, the working faces of both cuvettes located in

 one and those planes, and before. The cells installed the splitter of the initial beam into two parallel and offset relative to each other beam passing through the indicated cells, while the interference pattern detection unit contains a node comparing the difference of the paths of the interfering beams.

According to the second variant, a differential prismatic cuvette is connected to an additional differential prismatic cuvette, that the working faces of both cuvettes are located in the same planes, each cuvette has at least one refracting border of the cavities for the studied media, and the specified interfaces of different the cuvette is formed with their parallel working faces, pairwise equal in magnitude, angles of opposite sign, if half a body for the studied media and their boundaries p are aligned in the same sequence along the course of the beams, and of the same sign J if the cavities for exploration media and their interfaces are located in the opposite sequence along the course of the beams 5 and in front of the cuvette there is a split node of an inconsistent beam into two parallel and offset relative to each other beam, passing through the indicated cuvettes, while the block of registration of the interference pattern contains a node comparing the difference in the course of the interfering beams of the beams. According to the third variant, in order to improve the accuracy and the expansion of the dynamic range of measurements of the differential of the diameter of a cuvette is connected to at least one additional differential prismatic cuvette so that the working faces of the cuvette are located in the same planes and in different cuvettes the extending graces the section of the cavities for the study of 1k media is made up with flat and parallel working surfaces and different absolute values of angles in front of the cuzethes; the node is split; HP, of the running beam TTA are two parallel and displaced relative to each other, the passage through the indicated cuvettes and the registration block of the interference pattern contains a node for measuring the difference in the course of the I – T-beams. Due to the fact that, in the proposed way, the beams with eta are directed to the refractive boundary, distributing the test media at equal angles to both beams of the 14 lutap at the same angle and, consequently, the angle between the beams-w after the cuvee. When the beams are aligned with: the keg between I1-1MI, there is a difference in travel. proportional to the angle 5 on which both pivots are deflected, and by the value of the difference xoii, a about n, the accuracy is measured th (for 2-3 times) reached av. Because of the fact that the difference in the vjnpeAe flow in analyzing the interpolation of the picture5 is almost li1; it is directly related to the difference in the change of the difference in the difference of the difference in the difference in the course difference 6, b with an accuracy of lO-, the range and chfrenii difference; the refractive index with j: a is razrshov, in the prototype. -ia FIG. t shows a schematic diagram of an interference refractometer for the implementation of the proposed method; Fig 2 shows the principle scheme of an interference refractomatc in accordance with the first version: - 1st variant; in Fig. 3, differential H11ial prismatic: a cuvette connected to an additional dig | 4) with an optional cuvette according to the first embodiment; aa fig, 4 - schematic diagram of the interference-on refractometer according to vopo -.y; zariant; FIG. 5, HS: 5 according to the third embodiment; in fig. b - differential cuvette connected to: two optional dkfrenational cuvettes according to the m-fy version of the Interference Refractometer, (,,)) consists of the source of the T-band: To the interference node 2, performed, for example, according to the Hamen-Lebedez scheme, content; 1st Pointer 3; node 4 splitting the original light beam into two pairs and CMeuTGiiHi x with respect to each other ;,; ka (for example, “pictoscopes of parallelism) double-interrupted, with a caliper-gg.), pp, plate 5 n node g and sovg .; e Deni beam; Swt i; one onion “PPALOP-AHZHSh to node 4i usGg1koplo ;; by; .1 in the icterfermisngum node 2 i; jiki) epeb /; - ian jMGA of prismatic cuneta /. Differential prismatic kmvst.ch .. iiMeeT p.chokosloperedelnye p «b: chchey graii 9 and interlocking grakitsu section -O polochgag HccjseDuezhnyh media ... zygoyuleniyu at an angle V.J .; RnOOCH1I1 | . (pSihHM interferi young refractometer according to; GIG „work; .-. the students are formed, i ГУ -i о к с. в е а о т and с; о чк к а from l. h ei i pr :: A polarizer 3 and yjfeji 4 spansiiJieHHH of the original Iuchka L.- .j.Ba Id, goes;:; leljhx to the simile relationTirj; bHu DEuug Jiipyrt beam; both beam ;:: .: e: ku; o r; yr: y „with napran l 1c; with refractive index ;: -gzu p; area 10 aod equal to u: 1 qgb: y - 7 bundles of divi ;; igs on the same line;, equal to i ii; g {X 3 U are the differences of the refractive indices of the studied media, i; is the angle between the working faces cuvette and interface, and remain parallel to each other.When combining the refracted cuvette 7 beams, which is carried out using the node 6 combining light beams into one beam, the path difference between the beams is proportional to indtgti where d is the amount of beam displacement. the difference of the code determined in the analysis of the interference pattern using the block 8 of the registration of the interference pattern is judged on the difference of the refractive indices.

The interference refractometer, made according to the first variant (FIG. 2), also contains elements and nodes 1-10, as an interference refractometer shown in FIG. 1, as well as a quarter-wave plate 1 polarizer 12, node 13 for comparing the difference of the interfering beams, Of the two photosensors 1A and the angle indicator 15 of the reference positions of the polarizer 12, at which the photosensors 14 fix the offset position. Differential prismatic cuvette 7 is connected to an additional differential cuvette 16 (Fig. 3). The working faces 9 of both cuvettes are located in the same planes, and the refractive boundary of the section 10 cavities for the studied media in the additional differential cuvette 16 is parallel to the working faces 9 of both cuvettes.

If in the described interference refractometer, a He-Ne laser (0.63 µm) with a radiation power of 0.5 mW is used as the source, and the path difference is determined using a Senarmon compensator with an electro-optical modulator on a DCDR crystal with an accuracy of 10 1, with ct 45 ° and d = 0.6 mm, the difference of the refractive indices is determined with an accuracy of 1-10, which is two to three orders of magnitude greater than the accuracy of the known interference refractometer.

The interference refractometer (FIG. 2) S, works similarly to the interference refractometer shown in FIG. 1. The difference lies in the fact that, using node 13, comparison of the differences in stroke interfering: the beams measure the difference between the values of the difference in the stroke of the beams that pass through the differential cell 16. The difference in the path between the beams that pass through the differential prismatic cell 7, proportional difference of the refractive indices of the studied media, undt, and parasitic path difference associated with thermal and mechanical perturbations of the interference node. Between the beams that have passed the additional differential cell 16, only the parasitic path difference arises, since these beams pass through plane-parallel layers of the studied media and are not refracted. When measuring the difference between significant path differences interfering beams, corresponding to the cuvettes 7 and 16, the parasitic path difference is eliminated, which ensures an increase in the reproducibility of the measurements.

The measurement of the differences between the stroke difference values is carried out as follows.

The polarizer 12 is set to the position in which the photosensor 14 corresponding to the beams passing through the cuvette 7 registers the full darkening position of the field of view and turns to the position in which the complete darkening detects the photosensor 14 corresponding to the beams passed through the cuvette 16. With the help of the indicator 15 it is determined the angle between the indicated positions of the polarizer 12, which is proportional to the desired difference in the refractive indices of Lp.

The interference refractometer, made according to the second variant (Fig. 4), contains the same elements and nodes 1-15 as the interference refractometer according to the first variant. The difference lies in the fact that the differential prismatic cuvette is connected to an additional differential prismatic cuvette 17. Each of the cuvette 7 and 17 each has two interfaces, 10 and 18 cavities for the studied media. The cavities enclosed between the working faces 9 and the boundaries of the section 10 are intended for one of the test media, and the cavities enclosed between the boundaries of the section 10 and 18 for the second test medium. Thus, the cavities for the first and second test media, exposed by a given pair of interfaces 10 and 18, are located in the same sequence along the course of the bundles. The boundaries of the sections 10 and 18 of the cavities for the studied media 5 belonging to different cells 7 and 17 are, with the working faces 9, the angle angles of opposite sign equal in magnitude to each other. The interference refractometer according to the second variant works in the same way as the first variant. The difference lies in the fact that in the cuvette 7 the beams are refracted twice, deflected by an angle proportional to nCtgot, -I- tgctj), and when the beams are combined, a path difference occurs between them, proportional to in (tg o (., + Tgiy ,) Between the beams corresponding to the cuvette 17, the difference in absolute magnitude also appears with the opposite sign. Therefore, the difference between the values of the difference of the beam travels corresponding to the cuvettes 7 and 17 is proportional to 2und (.7 + + tgw-j), and in particular, with | c (, jl g - It is equal to 4 & ndtgd. Thus, compared with the first and second A refractometer provides a fourfold increase in the accuracy of measurements. However, the cuvette used in the second version is difficult to manufacture. So, the second variant of the interference refractometer can be used when it is necessary to realize an extremely high accuracy of measurements. Interference refractometer, according to the third variant (Fsh, 5) S contains the same elements and nodes 1-175 as the first and side variants of the interference refractometer. The difference lies in the fact5 that the refractive gravels, the section of the cavities for the test media in different differentiations in the prismatic cuvettes 7 and 17, are different with an absurd yrnbj size (Fig. 6). Moreover, in the additional differential prismatic cell 17, the indicated angle is 1-3 times less in absolute value than in the cell 7. The interference refractometer (Fig. 5) works in the same way as in the first version. The difference is in that 610 that at large values of the difference between the refractive indices, 1; and when between the shells, corresponding to the cuvette, there arises a difference in the path exceeding one order of interference, between the two. beams corresponding to 1–1 and an additional cuvette 17, a path difference arises that does not preserve one order of interference (since the resulting path difference is proportional to the value of the tangent of the refracting angle, which is 1–3 orders of magnitude smaller in the cuvette 17). With the help of the interference pattern registration unit 8, the difference between the values of the path differences of the interfering beams that have passed through the cuvette is determined; 7 and 16, as well as the cells that have passed through the cells 17 and 16. In this case, the difference between the refractive indices is proportional - the path difference between the beams passing through the cell 7 is determined to an accuracy of the whole interference patterns, and the number of the whole interference orders determines the outcome of the difference between the points between the points passed to the kugzet 17. A significant expansion of the dynamic measurement area in this scenario is achieved by the possibility of simultaneously determining the number of seconds. interference and difference values; h of the stroke at the limit of 1X o.clock;) it is of the order of the differential, Under conditions mx, when temperature and mechanical interference {interference perturbations of the ion node are small, the second additional cell 16 can not be used: In this case, the interference pattern detection unit contains a node for measuring the difference in the interfering distance of the beams. Compared with the 1st, 3rd, and second variants of the interference / refractometer, the third variant allows one to determine large rolls of the difference between the refractive indices with the same accuracy that is necessary. G -particles, when determining small changes in concentrates5-w of highly concentrated solutions, are caused by iii .biX effects: sorption, npe.o, r; araejMos invention C ;;: 1, naturally and refractometric a-alisa can be set S the basis of the new. devices designed to solve special problems in the new sections of the sciences (for example, in molecular Onology and genetics in the study of the quantity and quality of the composition of solutions, the isolation

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which is time consuming and is hard to produce in micro-amounts).

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Claims (3)

INTERFERENCE METHOD FOR DETERMINING REFRACTION INDEX REFRACTIONS AND INTERFERENCE REFRACT METER FOR ITS IMPLEMENTATION (ITS OPTIONS) (57) 1. The interference method for determining the difference in refractive indices by passing a light beam through a differential prism cell with the studied media and subsequent analysis of the resulting interference pattern, characterized in that, in order to improve the accuracy of measurements, the original the light beam is first split into two beams displaced relative to each other and sent to the refracting interface of the studied media in a differential prismatic cell equal angles, and the difference in refractive indices is judged by the difference in the course of the interfering beams, determined by analyzing the interference pattern. SU. ,, 1121606> <Put.1 2. An interference refractometer containing an interferometer with a differential prismatic cell installed in it along the beam of light, an interference pattern recording unit, which should be used in order to increase the accuracy and reproducibility of measurements, a differential prismatic cell connected to an additional differential prismatic cell, in which the interface between the cavities for the studied media is parallel to the working faces of both cells, the working faces of both cells are located in the same plane In front of the cuvettes, there is a knot for splitting the initial beam into two parallel and offset relative to each other beams passing through these cuvettes, while the block for recording the interference pattern contains a node for comparing the differences of the interference paths 1 12 1 6 (56 angles of opposite sign equal in absolute value if the cavities for the studied media and their interfaces are located in the same sequence along the beams, and the same sign if the cavities for the studied media and their interfaces are in opposite the sequence along the beams, and in front of the cuvettes there is a knot for splitting the initial beam into parallel and mixed beams passing through these cuvettes, while the interference pattern registration unit contains um site comparison of differences in the course of interfering beams. 4. An interference refractometer, containing an interferometer with a differential prismatic cell installed in it along the beam of light, a recording unit for the interference pattern, which differs in that, in order to increase the beams. 3. An interference refractometer containing an interferometer with a differential prismatic cell installed in it along the light beam, an interference pattern recording unit, which should be used in order to increase the accuracy and reproducibility of measurements, differential accuracy and expansion of the dynamic range of measurements, the differential prism cell is connected to at least one additional differential prism cell, so that the working faces of the cell are located in one x and the same planes, moreover, in different cuvettes, the prismatic cuvette refracting the cavity interfaces for the media under study is connected to an additional differential prismatic cuvette so that the working faces of both cuvettes are located on the same planes, each cuvette has at least one refracting the interface between the cavities for the studied media, and the indicated interface between different ditches make up with their plane-parallel working faces in pairs make up with plane-parallel working faces nye angles in absolute value, it is located in front of cuvettes initial beam splitting assembly on two parallel and displaced relative to each other of the beam passing through said cuvette block and recording the interference pattern comprises a stroke difference measurement unit blowing the interfering beams.