RU1770771C - Device for measuring radiation source indicatrix and scattering of specimens under action of radiation beams upon them - Google Patents

Abstract

Usage: in the analytical apparatus when studying the optical properties of various materials in the process of exposure to powerful beams of electromagnets or ionizing radiation, Summary of the invention: the device contains a sample 1, which is affected by a radiation beam 2, the polarizer 3 is flexible

Description

The invention relates to analytical equipment and can be used to study the optical properties of various materials when exposed to powerful beams of electromagnetic or ionizing radiation.

A device for studying the optical properties of materials is known, consisting of a test light source (sample) fixed in a holder, a two-lens capacitor, a spectrum-analyzing photosensor (consisting of a spectral device and a photodetector) and recording equipment. The first condenser lens projects radiation from the test sample in the plane of the second anti-vignetting lens located near the entrance slit of the spectral device. The last lens projects the first lens, in the plane of the input lens of the spectral instrument. The spectrum obtained by decomposing the radiation from the test sample in the spectral device is converted by the photodetector into electrical signals proportional to the spectral illumination, which are then fed to the recording apparatus 1 for processing. Such a device allows reliable data on the spectral composition of radiation from the test sample to be obtained by obtaining uniform illumination in the spectrum. The disadvantages of the known device are the dependence of the sensitivity of the spectral device on the polarization of the studied radiation and the reception of this radiation in one strictly chosen direction.

The closest in technical essence and the achieved result to the claimed device is a device for measuring the indicatrix of the radiation source, containing the holder of the radiation source (test sample), sequentially located and optically connected by a flexible fiber, a condenser and

a spectrum-analyzing photosensor, a measuring system connected to the photosensor, the end of the fiber closest to the sample being rotatable around an axis passing through the sample surface to be examined and intersecting the optical axis of the fiber at a right angle 2.

In addition, the device comprises a mechanical coordinate device made in the form of a platform with a plate provided with a movement mechanism along the three perpendicular coordinate axes, which is mounted for rotation about an axis parallel to one of the coordinate axes. The first shoulder of the L-shaped pillar is parallel to the plane of the plate, and on the second shoulder of this pillar is fixed the first end of the fiber with the possibility of movement along its optical axis. An L-shaped post is mounted on the plate to rotate about an axis that is the pivot axis of the end of the fiber. This axis is perpendicular to the axis of rotation of the plate and intersects with it and the optical axis of the fiber at one point, coinciding with the center of the end face of the first end of the fiber. The radiation source is fixed to the holder. Light guide, condenser and

a spectrum analyzing photosensor is mounted on a mechanical coordinate device.

This device allows the study of spectral indicatrixes of radiation. Moreover, the use of a fiber, which is a depolarizer, makes it possible to eliminate errors associated with a significant dependence of the sensitivity of the analyzing spectrum of the photosensor on the polarization of the radiation under study.

A disadvantage of the known device is chromaticity, leading to defocusing of the entire optical system and to a change in the area from which the radiation

investigated in measurements in a certain spectral range.

Another drawback is the need to combine the end of the fiber with the surface under study, which prevents both polarization measurements and optical measurements of the samples when they are exposed to radiation beams arriving at the surface from the same half-plane where the fiber is located .

The aim of the invention is to increase the reliability and informativeness of measurements with a constant spatial arrangement of the axis of the radiation beam and the optical axis of the photosensor.

1 is a kinematic diagram of a device; Fig. 2 is a kinematic diagram of a rotation and displacement assembly of a polarizer.

The device contains a test sample 1, the surface of which is affected by a radiation beam 2, a polarizer 3, a flexible optical fiber 4, an optical system consisting of a capacitor lens 5 and an anti-vignette lens 6, which is located in front of the exit slit 7 of the spectrum-analyzing photosensor (in the diagram not shown). In addition, the device contains a measuring system (not shown in the diagram). The optical fiber 4 and the capacitor lens 5 are made of the same material, and the spectral dependences of the refractive index of the anti-vignetting lens 6 and the material of the lens 5 coincide up to a constant factor.

The test sample 1 is fixed in the sample holder 8 so that the plane of the sample holder coincides with the irradiated plane of the sample, which is the radiation source, and the holder 8 is mounted with the possibility of rotation of its axis 9 in the bearing mounted on the shoulder of the L-shaped bracket 10. Axis 9 is coaxial with the geometric axis 11, which coincides with the line of intersection of the plane perpendicular to the axis of the beam with the plane of the sample holder 8. The L-shaped bracket 10 is attached with its second shoulder to the axis 12 and has the ability to rotate its axis 12 into the base fixed to one of the planes of the rectangular corner base 13. The axis 12 is aligned with the geometric axis 14 coinciding with the axis of the beam 2. On the second plate of the corner base 13 there is an L-shaped stand 15 with the possibility of rotation around an axis coinciding with the geometric axis 10, which perpendicular to the axis of the beam, passes through the point of intersection of the optical axis of the fiber 17 and the axis of the beam

radiation 2, perpendicular to the plane of this base plate, the fluuupoi of the probe 15 can be realized using a pair of axis-bearing similar to the one described above. On the second arm of the L-shaped post 15, the first end of the light guide 4 is fixed. In addition, the corresponding elements of the kinematic scheme of the device are located so that the axes 11,14,16 and 17 intersect the water point. On the second arm of the L-shaped pillar above the optical fiber, a holder 18 (only a part of it is shown in Fig. 1) of the polarizing and displacement and rotation unit 3 is mounted. The kinematic diagram of this unit is shown in Fig. 2. On the holder 18, the axis 19c is rotatably mounted with a threaded screw on it, on which the nut of the carriage 20 is mounted. The carriage 20 can be moved along this screw perpendicular to the axis 17. On the carriage 20 coaxially with the optical axis 17 of the first end of the optical fiber, axis 21 is mounted to rotate around the floor axis 17. Polarizer 3 is fixed inside this axis. that its optical axis coincides with axis 17. The possibility of rotation of axis 21 is provided by a kinematic pair of worm wheel 22 - worm to 23. Worm wheel 22 is mounted coaxially on the hollow axis 21, and the worm to 23 is rotatably mounted on the carriage 20. The second end of the optical fiber 4 and the lens 5 (see Fig. 1) are mounted on carriages 24 and 25, respectively, which can be moved along the optical axis due to the kinematic coupling 26 and 27, respectively. These communications are identical in structure and include an axis with a screw cut on it, along which the nut of the corresponding carriage can move, and are connected to constant gear ratios with a common kinematic link 28 by means of a kinematic pair, one of the elements of which is fixed on the axis of the corresponding link, and the second on the axis of the link 28. Pin 6 is rigidly fixed on the housing 29 of the device. A value proportional to D. is supplied to the input of the general kinematic connection.

The device operates as follows. First, the sample 1 in the holder 8 is installed at certain angles with respect to the axis of the beam 2 and the optical axis 17 of the first end of the fiber, and the entire optical path is tuned to measure radiation at a specific wavelength Do and with a given polarization P0 (see Fig. 1) . The angle at which the beam of radiation 2 falls on the test surface of the sample is defined as the angle between the normal 30 to this

the surface at the intersection of the axes 2 (14), 11.16 and 17 and the axis of the beam 2, and is denoted by y. The direction in which the light guide receives radiation from the sample is characterized by two angles o: I /. The angle of-angle between the projection 31 of the normal 30 in the plane passing through the axes 17 and 2, and the axis 17. The angle ft is the angle between the axes 16 and 11. The beam 2 is directed at an angle y to the surface of the sample. The resulting electromagnetic radiation in the direction characterized by the angles a l ($ passes through the polarizer 3, which transmits only light with a given polarization, and hits the end face of the first end of the optical fiber 4. Radiation extracted from the solid angle is which is determined by the distance from sample 1 to the end of the first end of the fiber and the working area of this end, in a given direction, is transmitted by the fiber to the other end, from the end of which is projected by lens 5 in the plane of the entrance slit 7 of the analyzer pektr photosensor. Simultaneously lens 6 shows the lens plane 5N and the input lens of a photosensor (not shown). Then, an electric signal from the photosensor is proportional to the radiation, which is characterized Le. a, A y and Ro is supplied to a measuring system for processing and recording.

Let us denote the optical distances between the second end of the fiber 4 and lens 5, lenses 5 and 6, respectively, at, 32. For AO and aa, they have the form

,(1)

ad-d-g-b. (2)

A 1 + 1

where / is the magnification of the lens 5;

is is its focal length.

The focal length fe of lens 6 is determined from the relation:

(3)

fe az f

where F is the focal length of the input lens that analyzes the spectrum of the photodetector, it remains in the entire working range of the spectrum,

Further research is carried out by scanning the emission spectrum at constant values of a, D y and Po. When switching to measurements at a different wavelength At, the alignment of the optical path is violated, which is associated with the spectral dependence of the refractive index of the lenses and the fiber. Because lens 5 and the light guide are made of the same material, then the change in fs, a, therefore, ai, 82 according to equalities (1) and (2)

fifty

5

5

are proportional to one value D. The value of f5 (H1) is determined by etc fs (/ U) as

fs (Ai) fs (C) (1 + D), (4) where D is the spectral change in the focal length of the lens 5.

The restoration of conjugation of optical elements at the inter-element spaces ai and 32 is carried out as follows. A rotational moment proportional to D is supplied to the input of the common kinematic coupling 28. Rotation from the axis of the common coupling 28 is transmitted by kinematic pairs of the links 26 and 27 to the screw-nut pair and the carriage connected to the corresponding nut is moved along the optical axis until it is installed in desired position. In this case, the lens 5 and the second end of the fiber 4 are moved relative to the lens 6. The constant gear ratios M and the pitch h of the thread of the screw-nut pairs have the following values for the kinematic

l 2

fs, for communication 27 - Mh

0

0

5

A-1

connection 26 Mh

d

 d l fs. The coincidence of the measurement of the spectral dependences of the refractive indices of the anti-vignetting lens material b and the lens material 5 with an accuracy of a constant factor ensures that the lens 6 is in conjunction with the optical path of the device over the entire working range of the spectrum.

After taking the spectrum for given a, ft, y and Po, the radiation spectrum is measured at the same angles, but with a different polarization PL

For this purpose, a torque is supplied to the input of the kinematic pair of hearts to the 23-worm wheel 22, as a result of which the floor rotates the axis 21 around the axis 17 until the polarizer is set to a predetermined position. Then, the spectrum is scanned again. When measuring the total radiation flux from the polarizers, a torque is applied to the axis 19, as a result of which a nut is installed on its screw, along with the polarizer carriage 20, it moves along this screw and perpendicular to the axis 17 until the polarizer leaves the optical path. After carrying out the polarization measurements, the angle a is changed by a predetermined step Yes by turning the L-shaped rack 15 about the axis 16. Then spectral and polarization measurements are made as described above. After taking measurements over the entire range with an angle a (- 90 ° a 90 °), the angle is changed (3 to the selected uar Д /,

by turning around the axis 14 of the L-shaped bracket 10. Then the spectra are measured for different P and a. Carrying out measurements in increments of D / 3 over the entire range of angles (-90 °), a set of data is obtained representing the value of the intensities of spectral radiation with different polarizations in the directions characterized by angles a and / 3, L (A, a , ft, y, P). The spectral indicatrices of radiation from the sample having different polarizations are determined from these values. These data were obtained for a given angle of incidence of the radiation beam onto the sample — angle y. The spectral indicatrixes of radiation from the sample at a different value of y are determined after the sample is installed at a given angle to the beam axis by rotating the sample holder 8 around axis 11.

A specific implementation of the device was carried out on the basis of a modernized complex of spectral computational universal KSVU-23, which is a spectrum-analyzing photosensor and measuring system. The spectrum-analyzing photosensor consisted of an MDR-23 monochromator and two photodetectors of the type ФЭУ-100 and ФЭУ-62 and had the following parameters: working spectrum range 200 nm - 1200 nm; focal length of the input lens F 600 mm; aperture ratio of the lens 1: 6; entrance slit height 12 mm.

The optical path elements of the device had the following parameters: the diameters of the quartz polarizer, quartz fiber, quartz lens 5, and fluorite lens 6 were 8 mm, b mm, 25 mm, and 12 mm, respectively; lens enlargement 5

amounted to / 1 2, and A 1.5 and was unchanged throughout the working range of the spectrum. Gear ratios and pitch of a screw-nut of a kinematic link 26 M 270 mm and a link 27 M 180 mm. Kinematic links 19 and 23 provided unlimited rotation of the polarizer around its axis and its withdrawal from the optical path. The diameter of the radiation beam on the surface of the sample was 1.5 mm.

The remaining parameters of the device for two waves, limiting the operating range of the spectrum, are given below

A 200 nm. D 0, fs 60 mm. fe 138.46 mm, ai 90 mm, 32,180 m;

I am 1000 nm. D 0.209, fs - 72.54 mm, fe 159.7 mm, ai 108.81 mm, 32 217.62 mm.

The invention allows, in comparison with the prototype, to increase the information content of measurements by studying the optical properties of the material when exposed to it

a beam of radiation from the same half-plane where the fiber is located, polarization measurements and emission of spectral radiation indicatrixes at 5 different angles of incidence of the beam on the surface of the sample. At the same time, the reliability of measurements increases, since in the prototype, the power transmittance is reduced compared to the 10 value for A 200 nm by 17.2 times for A 1000 nm due to misalignment of the optical circuit. Simultaneously, the radiation is received from different sites as due to the spectral dependence of the parameters of the elements

5 of the optical path, and due to the rotation of the end of the fiber.

Claims (2)

SUMMARY OF THE INVENTION 1. A device for measuring the indicatrix of a radiation source and scattering of samples when exposed to radiation beams, comprising a sample holder, the plane of the sample holder matching the irradiated plane of the sample being a radiation source. 5 sequentially located and optically interconnected by a flexible light guide, an optical system including a motionless fixed lens, as well as a spectrum-analyzing photosensor, and 0 a measuring system connected to the photosensor, while the end of the optical fiber closest to the sample holder is mounted on one shoulder of the L-shaped rack, the other shoulder of the L-shaped rack is located on the base, the L-shaped rack is mounted with the possibility of rotation around an axis passing through the point of intersection of the optical axis of the fiber and the axis of the beam of radiation, perpendicular to the plane of the base, characterized in that, in order to increase the reliability and information content of the measurements with a constant spatial arrangement of the beam axis from Scientists and the optical axis of the photosensor. 5, the sample holder is mounted to rotate both around the axis of the beam perpendicular to the axis of rotation of the L-shaped rack and around the axis coinciding with the intersection line of the plane perpendicular to the axis of the beam with the plane of the sample holder, the axis of rotation of the sample holder , the axis of rotation of the L-shaped rack and the optical axis of the end of the fiber are crossed at one point, between 5, a polarizer is mounted with a sample holder and a light guide to rotate around its axis and move perpendicular to the axis of the light guide, the second end of which and all lenses of the optical system mounted to move along the optical axis of the optical system. 2. Device pop. 1, characterized in that the anti-vignetting lens is made of one material, and the optical fiber and all other lenses of the optical system are made of another material, and the spectral dependences of the measurements showed the refractions of the material of the anti-vignetting lens and the material of the other lenses coinciding to within multiplier constants. 3, The device according to claim 2, characterized in that all the lenses of the optical system and the second end of the fiber are mounted in frames connected by a common kinematic connection with constant gear ratios. 10 . 2