1. A device for calibrating a spatial measurement position of a laser scattering diagnostic system is characterized by comprising: the device comprises a grating ruler (1), a screw rod displacement table (2), a reference light beam (3), a light source (5), a mounting and positioning support (6), an incident optical fiber bundle connecting wire (7), a photoelectric detection module (8), an optical fiber head (9), a data acquisition and processing device (10), a sliding block (11), an acquisition trigger signal receiving wire (13), an acquisition position signal wire (14), a light-transmitting glass window (15), an acquisition lens (16), a light intensity signal wire (17), an acquisition optical fiber group frame (18) and a calibration light beam (19);

a screw rod displacement table (2) is fixedly installed on the installation positioning support (6), a grating ruler (1) is installed on one side edge of the screw rod displacement table (2), a sliding block (11) is arranged on the screw rod displacement table (2), and an optical fiber head (9) is installed on the sliding block (11); the optical fiber head (9) is connected with the light source (5) through an incident optical fiber bundle connecting wire (7); the grating ruler (1) is connected with the data acquisition processing device (10) through an acquisition position signal line (14); the calibration light beam (19) is emitted from the interior of the optical fiber head (9);

a light-transmitting glass window (15), a collecting lens (16), a plurality of collecting optical fiber group frames (18) and a photoelectric detection module (8) are sequentially arranged in the horizontal direction of the end part of the optical fiber head (9) emitting the calibration light beam (19); the photoelectric detection module (8) is also connected with a data acquisition and processing device (10) through a light intensity signal line (17);

the front end of the end part of the optical fiber head (9) emitting the calibration light beam (19) is arranged on the reference light beam (3), and the reference light beam (3) is vertical to the central light beam of the calibration light beam (19).

2. The device for calibrating the spatial measurement position of the laser scattering diagnostic system according to claim 1, wherein: the whole screw rod displacement table (2) is of a long plate structure, and a contact switch A (4) and a contact switch B (12) are respectively mounted at the head end and the tail end of the screw rod displacement table (2); the contact switch A (4) and the contact switch B (12) are respectively connected with the data acquisition processing device (10) through an acquisition trigger signal receiving line (13).

3. The device for calibrating the spatial measurement position of the laser scattering diagnostic system according to claim 2, wherein: a plurality of screw rods are arranged between the head end and the tail end of the screw rod displacement table (2), the sliding block (11) is arranged on the screw rods, and the sliding block (11) can slide on the screw rods; and when the sliding block (11) slides to the head end and the tail end of the screw rod displacement table (2), the sliding block can be respectively contacted with the contact switch A (4) or the contact switch B (12).

4. The device for calibrating the spatial measurement position of the laser scattering diagnostic system according to claim 3, wherein: the quasi-monochromatic light output by the light source (5) comprises: quasi-monochromatic light in the visible band and quasi-monochromatic light in the near-infrared band.

5. The device for calibrating the spatial measurement position of the laser scattering diagnostic system according to claim 1, wherein: a plurality of acquisition data lines are connected between the acquisition optical fiber group frames (18) and the photoelectric detection module (8).

6. The device for calibrating the spatial measurement position of the laser scattering diagnostic system according to claim 5, wherein: the calibration light beam (19) emitted from the optical fiber head (9) passes through the transparent glass window (15) in the horizontal direction, is collected to the collection optical fiber group frame (18) by the collection lens (16), and is transmitted to the photoelectric detection module (8) through a plurality of collection data lines between the collection optical fiber group frame (18) and the photoelectric detection module (8).

7. The device for calibrating the spatial measurement position of the laser scattering diagnostic system according to claim 4, wherein: the wavelength range of the quasi-monochromatic light output by the light source (5) is 500 nm-1100 nm.

8. The device for calibrating the spatial measurement position of the laser scattering diagnostic system according to claim 1, wherein: the slide block (11) is always in a right angle with the grating ruler (1) on the screw rod displacement table (2).

9. The device for calibrating the spatial measurement position of the laser scattering diagnostic system according to claim 8, wherein: the number of the collecting optical fiber group frames (18) is two.

10. The device for calibrating the spatial measurement position of the laser scattering diagnostic system according to claim 9, wherein: one of the two collecting optical fiber group frames (18) and the optical fiber bundle on the frame are used for measuring plasma scattered light, and the other collecting optical fiber group frame (18) is used for calibrating the electronic temperature measuring position.

11. A calibration method of a calibration device for a spatial measurement position of a laser scattering diagnostic system as claimed in any one of claims 1 to 10, characterized by comprising the steps of:

the method comprises the following steps: confirming that the all-optical path of the laser scattering diagnosis system is debugged, wherein the reference light beam (3) indicates the x and y coordinates of the space measurement position in the scattering experiment, the z coordinate is a calibrated item to be measured, the space measurement position calibration device in the laser scattering diagnosis system is moved to the inside of a vacuum chamber after being installed outside the vacuum chamber, the front end x and y coordinate position of the end part of a calibration light beam (19) emitted by an optical fiber head (9) is adjusted according to the x and y coordinate positions of the reference light beam (3) during installation, and the path of a sliding block (11) when moving on a screw rod displacement table (2) is enabled to be coincident with the z direction of the reference light beam (3) as much as possible;

turning on a light source (5) to output 655nm visible red light, and switching two acquisition optical fiber group frames (18) to the working position of the optimal calibration space point;

step two: during testing, the sliding block (11) slides to the contact switch A (4) on the screw rod displacement table (2) and is in contact with the contact switch A (4); starting a data acquisition processing device (10), and setting an acquisition trigger mode of the data acquisition processing device (10) to be TTL high-level trigger;

at the moment, the sliding block (11) is rapidly moved to a contact switch B (12) on the screw rod displacement table (2) from a contact switch A (4) on the screw rod displacement table (2), a TTL (transistor-transistor logic) trigger signal of the data acquisition processing device (10) is changed into a high level, and the data acquisition processing device (10) is used for synchronously acquiring a position signal of the grating ruler (1) and light intensity signals output by photoelectric detection modules (8) corresponding to different measurement positions;

step three: the time that the sliding block (11) is rapidly moved to the contact switch B (12) on the screw rod displacement table (2) by the contact switch A (4) on the screw rod displacement table (2) is completed within 3-5 seconds, when the sliding block (11) contacts the contact switch B (12), a TTL (transistor-transistor logic) trigger signal of the data acquisition processing device (10) is changed into a low level, the data acquisition process is finished, and data processing is carried out;

the data processing step comprises:

(a) confirming the time sequence of the position signal of the grating ruler (1) and the light intensity signal output by the photoelectric detection module (8) by the TTL trigger signals provided by the contact switch A (4) and the contact switch B (12);

(b) confirming the single peak position of the light intensity signal output by the photoelectric detection module (8);

(c) comprehensively analyzing the results obtained in the steps (a) and (b) and the position signal of the grating ruler (1) to obtain a complete space measurement position result;

step four: within the wavelength range of 600 nm-1100 nm, adjusting the light source (5) to output 5-10 quasi-monochromatic lights with different wavelengths in sequence, and repeating the second step to the fourth step; and (4) calculating an average value of the multiple measurement results, namely finishing the calibration work of the electronic temperature measurement position.

Background

The laser scattering diagnosis system is one of the effective diagnosis tools in Tokamak experiment physical research, and can be used for measuring the electron temperature and the electron density of plasma in a high-time and high-space resolution manner. The pulse Nd-YAG laser is a common excitation light source of a laser scattering system, the pulse width of laser output by the pulse Nd-YAG laser is about 10ns in an electro-optical Q-switching mode, the wavelength of output fundamental frequency laser is 1064nm, the energy of single pulse laser is about 4J, and the repeated working frequency can reach 100 Hz. When a 1064nm laser beam passes through a glass window and a metal pipeline of the tokamak device and then enters a tokamak vacuum chamber, the direction and the position of the laser beam can be accurately controlled.

However, since 1064nm laser is invisible near infrared ray, a visible 532nm or 650nm indicating laser beam is often used during adjusting the incident light path of the laser. A typical 1064nm laser beam may enter the plasma vertically or horizontally in the mid-plane.

Taking 1064nm laser beam entering plasma vertically as an example, the electron movement rate of high temperature plasma is very large, and due to doppler effect, the wavelength of the scattered light generated after the incident laser is scattered by electrons changes greatly, possibly to 500 nm. Therefore, the requirements for the scattered light condenser lens are: (1) the condensing lens has a larger field of view, namely, the light beam receiving capacity is stronger, (2) the effective collection wavelength range is 500-1100 nm, (3) the condensing lens has: high light transmittance, achromatic color, and achromatic aberration.

The electron temperature and the electron density are varied in spatial distribution, and in order to compare the experimental result with a theoretical model, the spatial resolution of the laser scattering diagnostic system needs to be improved as much as possible, an observation area (i.e., the total scattering length) of the condenser lens is divided into a plurality of small line segments, and the central point of each line segment is a measurement position and is also called a spatial point.

The calibration of the space measurement position is basic data used for calculating the scattering angle of each space point in the laser scattering diagnosis system, and the accuracy of the calibration influences the shape of a scattering spectrum, so that the electronic temperature value calculated according to experimental data is influenced;

in the prior art, the data of the spatial points are generally calculated by adopting the object-image corresponding relation of the optical design of the condensing lens, and the accuracy of the calculated data of the spatial points is low due to the processing and installation errors of an optical machine. In addition, in the prior art, a light ray reverse tracking method can also be used for calibrating a space point, namely, a light transmitting optical fiber bundle arranged on an image surface of a condenser lens is utilized, the other end of the light transmitting optical fiber bundle is irradiated by visible light, so that an image is formed in a vacuum chamber, and a measurer measures the position in the vacuum chamber by using a straight ruler, but the efficiency and the accuracy of the measuring method are poor.

Therefore, it is necessary to design a calibration device and a calibration method for a spatial measurement position of a laser scattering diagnostic system to solve the above technical problems, in order to overcome the above disadvantages of the method or device for measuring spatial points in the prior art.

Disclosure of Invention

Aiming at the defects of the prior art, the invention designs a calibration device and a calibration method for a spatial measurement position of a laser scattering diagnosis system, which are used for solving the technical problems of low calibration efficiency and poor calibration accuracy of the spatial measurement position generated when an object-image corresponding relation or a light ray reverse tracking method of optical design of a condensing lens is adopted for spatial point calibration in the prior art.

The technical scheme of the invention is as follows:

an apparatus for calibrating a spatial measurement position of a laser scattering diagnostic system, comprising: the device comprises a grating ruler, a lead screw displacement table, a reference light beam, a light source, an installation positioning support, an incident optical fiber bundle connecting wire, a photoelectric detection module, an optical fiber head, a data acquisition processing device, a sliding block, an acquisition trigger signal receiving wire, an acquisition position signal wire, a light-transmitting glass window, an acquisition lens, a light intensity signal wire, an acquisition optical fiber group frame and a calibration light beam;

a screw rod displacement table is fixedly arranged on the mounting and positioning support, a grating ruler is arranged on one side edge of the screw rod displacement table, a sliding block is arranged on the screw rod displacement table, and an optical fiber head is arranged on the sliding block; the optical fiber head is connected with a light source through an incident optical fiber bundle connecting wire; the grating ruler is connected with the data acquisition and processing device through an acquisition position signal line; the calibration light beam is emitted from the interior of the optical fiber head;

a light-transmitting glass window, a collection lens, a plurality of collection optical fiber group frames and a photoelectric detection module are sequentially arranged in the horizontal direction of the end part of the optical fiber head, which emits the calibration light beam; the photoelectric detection module is also connected with the data acquisition and processing device through a light intensity signal line;

the front end of the end part of the optical fiber head, which emits the calibration light beam, is arranged on the reference light beam, and the reference light beam is vertical to the central light beam of the calibration light beam.

The whole screw rod displacement platform is of a long plate structure, and a contact switch A and a contact switch B are respectively arranged at the head end and the tail end of the screw rod displacement platform; and the contact switch A and the contact switch B are respectively connected with the data acquisition and processing device through acquisition trigger signal receiving lines.

A plurality of screw rods are arranged between the head end and the tail end of the screw rod displacement table, the sliding block is arranged on the screw rods, and the sliding block can slide on the screw rods; and when the sliding block slides to the head end and the tail end of the screw rod displacement table, the sliding block can be respectively contacted with the contact switch A or the contact switch B.

The quasi-monochromatic light output by the light source comprises: quasi-monochromatic light in the visible band and quasi-monochromatic light in the near-infrared band.

And a plurality of acquisition data lines are connected between the acquisition optical fiber group frames and the photoelectric detection module.

The calibration light beam emitted from the optical fiber head passes through the transparent glass window in the horizontal direction, is collected to the collection optical fiber group frame by the collection lens, and is transmitted to the photoelectric detection module through a plurality of collection data lines between the collection optical fiber group frame and the photoelectric detection module.

The wavelength range of the quasi-monochromatic light output by the light source is 500 nm-1100 nm.

The slide block is always in a right angle with the grating ruler on the screw rod displacement table.

The number of the collecting optical fiber group frames is two.

One of the two collection optical fiber group frames and the optical fiber bundle on the frame are used for measuring plasma scattered light, and the optical fiber bundle on the other collection optical fiber group frame is used for calibrating the electronic temperature measurement position.

A calibration method of the calibration device for the spatial measurement position of the laser scattering diagnosis system comprises the following steps:

the method comprises the following steps: confirming that the all-optical path of the laser scattering diagnosis system is debugged, wherein the reference light beam indicates the x and y coordinates of the space measurement position in the scattering experiment, the z coordinate is a calibration item to be measured, after the device for calibrating the space measurement position in the laser scattering diagnosis system is installed outside a vacuum chamber, the device is moved to the inside of the vacuum chamber, and the x and y coordinate positions of the front end of the end part of the optical fiber head emitting the calibration light beam are adjusted according to the x and y coordinate positions of the reference light beam during installation, so that the path of the sliding block when moving on the screw rod displacement table is coincident with the z direction of the reference light beam as much as possible;

turning on a light source to output 655nm visible red light, and switching two acquisition optical fiber group frames to the working position of the optimal calibration space point;

step two: during testing, the sliding block slides to a contact switch A on the screw rod displacement table and is in contact with the contact switch A; starting a data acquisition processing device, and setting an acquisition trigger mode of the data acquisition processing device to be TTL high-level trigger;

at the moment, the slide block is quickly moved to a contact switch B on the screw rod displacement table from a contact switch A on the screw rod displacement table, a TTL trigger signal of the data acquisition processing device is changed into a high level, and the data acquisition processing device synchronously acquires a position signal of the grating ruler and light intensity signals output by photoelectric detection modules corresponding to different measurement positions;

step three: the time that the sliding block is rapidly moved to the contact switch B on the screw rod displacement table by the contact switch A on the screw rod displacement table is completed within 3-5 seconds, the moving speed is increased, the signal-to-noise ratio of the collected square wave signal can be improved, when the sliding block is contacted with the contact switch B, the TTL trigger signal of the collection processing device is changed into a low level, and the data collection process is finished; and processing the data;

the data processing step comprises:

(a) confirming the time sequence of the position signal of the grating ruler and the light intensity signal output by the photoelectric detection module by using TTL trigger signals provided by the contact switch A and the contact switch B;

(b) confirming the single peak position of the light intensity signal output by the photoelectric detection module;

(c) comprehensively analyzing the results obtained from the a and the b and the position signal of the grating ruler to obtain a complete space measurement position result;

step four: and within the wavelength range of 600 nm-1100 nm, adjusting the light source to output 5-10 quasi-monochromatic lights with different wavelengths, and repeating the second step to the fourth step. And (4) calculating the average value of the multiple measurement results, and finishing the calibration work of the electronic temperature measurement position.

The invention has the beneficial effects that:

the invention designs a calibration device and a calibration method for a space measurement position of a laser scattering diagnosis system, which can accurately calibrate space points in situ in a Tokamak vacuum chamber, and the obtained calibrated data can be used for calculating the scattering angle, the electron temperature, the plasma magnetic surface coordinate system and the like of each space point.

The device is arranged in a Tokamak vacuum chamber, has no influence on the positions and the working state of a light-transmitting glass window, a collecting lens, an emergent optical fiber bundle, a photoelectric detection module and a data collecting and processing device used for laser scattering diagnosis in the process of calibrating a space measuring position, and has little influence on the position and the working state of a collecting optical fiber group frame.

The position of the acquisition optical fiber group frame in the device can be switched, and the device has two acquisition optical fiber group frames which are transversely arranged side by side and are not arranged in front and back; the collecting optical fiber group frame is completely consistent with the installation position and the distance of the optical fiber bundle on the frame and the effective size of the end face of the optical fiber bundle. One of the collection optical fiber group frame and the optical fiber bundle on the frame are used for measuring plasma scattered light, and the other collection optical fiber group frame and the optical fiber bundle on the frame are used for calibrating the measurement position (space point) of the electron temperature. The lower part of the acquisition optical fiber group frame is also provided with a high-precision electric displacement table, so that the repeatability of the measurement process, and the reliability of the efficiency and the data accuracy are ensured.

This device still possesses the practicality and marks efficient characteristics, and the concrete performance does: the device adopts the grating scale as the position sensor, and utilizes the characteristics of high detection precision and response speed of the grating scale; the manual screw rod displacement table selected in the device is low in cost, long in effective stroke and low in difficulty of processing and analyzing the acquired signals.

The device also has the characteristics of light weight, compact structure and simple and convenient installation, fully considers the narrow and relative sealing of the internal space of the vacuum chamber, and plays a role in limiting the size, weight, installation and operation of the instrument.

In most cases, the main part of the scattering spectrum is in the near infrared band, the achromatic and aberration-eliminating focus of the condenser lens is mainly concentrated in the near infrared band (e.g. 800 nm-1100 nm), and there may be large errors in the measurement data of the optical fiber back-tracking method by irradiating the optical fiber with visible light.

The light source used by the invention not only can output quasi-monochromatic light in a visible wave band, but also can output quasi-monochromatic light in a near infrared wave band, on one hand, the measurement results under a plurality of light wavelengths can be compared, and on the other hand, the achromatic effect and the aberration eliminating effect of the condensing lens can be evaluated.

Drawings

FIG. 1 is a device connection diagram of a spatial measurement position calibration device of a laser scattering diagnostic system designed by the invention;

in the figure: 1-grating ruler, 2-lead screw displacement table, 3-reference beam, 4-contact switch A, 5-light source, 6-installation positioning support, 7-incident optical fiber bundle connecting line, 8-photoelectric detection module, 9-optical fiber head, 10-data acquisition processing device, 11-slide block, 12-contact switch B, 13-acquisition trigger signal receiving line, 14-acquisition position signal line, 15-transparent glass window, 16-acquisition lens, 17-light intensity signal line, 18-acquisition optical fiber group frame, 19-calibration beam

Detailed Description

The following describes in detail a device and a calibration method of a device for calibrating a spatial measurement position of a laser scattering diagnostic system according to the present invention with reference to the accompanying drawings and embodiments.

An apparatus for calibrating a spatial measurement position of a laser scattering diagnostic system, comprising: the device comprises a grating ruler 1, a screw rod displacement table 2, a reference light beam 3, a light source 5, an installation positioning support 6, an incident optical fiber bundle connecting wire 7, a photoelectric detection module 8, an optical fiber head 9, a data acquisition processing device 10, a sliding block 11, an acquisition trigger signal receiving wire 13, an acquisition position signal wire 14, a light-transmitting glass window 15, an acquisition lens 16, a light intensity signal wire 17, an acquisition optical fiber assembly frame 18 and a calibration light beam 19;

a screw rod displacement table 2 is fixedly mounted on the mounting and positioning support 6, a grating ruler 1 is mounted on one side edge of the screw rod displacement table 2, a sliding block 11 is arranged on the screw rod displacement table 2, and an optical fiber head 9 is mounted on the sliding block 11; the optical fiber head 9 is connected with the light source 5 through an incident optical fiber bundle connecting wire 7; the grating ruler 1 is connected with a data acquisition processing device 10 through an acquisition position signal line 14; the calibration light beam 19 is emitted from the inside of the fiber head 9;

a light-transmitting glass window 15, a collection lens 16, a plurality of collection optical fiber group frames 18 and a photoelectric detection module 8 are sequentially arranged in the horizontal direction of the end part of the optical fiber head 9 emitting the calibration light beam 19; the photoelectric detection module 8 is also connected with a data acquisition and processing device 10 through a light intensity signal line 17;

the front end of the fiber head 9 emitting the calibration beam 19 is arranged on the reference beam 3, and the reference beam 3 is perpendicular to the central beam of the calibration beam 19.

The whole lead screw displacement table 2 is of a long plate structure, and a contact switch A4 and a contact switch B12 are respectively arranged at the head end and the tail end of the lead screw displacement table 2; the contact switch A4 and the contact switch B12 are respectively connected with the data acquisition processing device 10 through the acquisition trigger signal receiving line 13.

A plurality of screw rods are arranged between the head end and the tail end of the screw rod displacement table 2, the slide block 11 is arranged on the screw rods, and the slide block 11 can slide on the screw rods; and when the slide block 11 slides to the head end and the tail end of the screw rod displacement table 2, the slide block can be respectively contacted with a contact switch A4 or a contact switch B12.

The quasi-monochromatic light output by the light source 5 comprises: quasi-monochromatic light in the visible band and quasi-monochromatic light in the near-infrared band.

A plurality of acquisition data lines are connected between the acquisition optical fiber group frames 18 and the photoelectric detection module 8.

The calibration light beam 19 emitted from the optical fiber head 9 passes through the transparent glass window 15 in the horizontal direction, is collected by the collecting lens 16 to the collecting optical fiber group frame 18, and is transmitted to the photoelectric detection module 8 through a plurality of collecting data lines between the collecting optical fiber group frame 18 and the photoelectric detection module 8.

The wavelength range of the quasi-monochromatic light output by the light source 5 is 500 nm-1100 nm.

The slide block 11 is always in a right angle with the grating ruler 1 on the screw rod displacement platform 2.

The number of the collecting optical fiber group frames 18 is two.

One of the two collection optical fiber group frames 18 and the optical fiber bundle on the frame are used for measuring plasma scattered light, and the other collection optical fiber group frame 18 is used for calibrating the electronic temperature measurement position.

A calibration method of the calibration device for the spatial measurement position of the laser scattering diagnosis system comprises the following steps:

the method comprises the following steps: confirming that the all-optical path of the laser scattering diagnosis system is debugged, wherein the reference light beam 3 indicates the x and y coordinates of the space measurement position in the scattering experiment, the z coordinate is a calibration item to be measured, after the space measurement position calibration device in the laser scattering diagnosis system is installed outside a vacuum chamber, the device is moved to the inside of the vacuum chamber, the front end x and y coordinate position of the end part of a calibration light beam 19 emitted by an optical fiber head 9 is adjusted according to the x and y coordinate position of the reference light beam 3 during installation, and the path of the sliding block 11 when moving on the screw rod displacement table 2 is enabled to be coincident with the z direction of the reference light beam 3 as much as possible;

turning on the light source 5 to output 655nm visible red light, and switching the two acquisition optical fiber group frames 18 to the working position of the optimal calibration space point;

step two: during testing, the sliding block 11 slides to a contact switch A4 on the lead screw displacement table 2 and contacts with a contact switch A4; starting the data acquisition processing device 10, and setting an acquisition trigger mode of the data acquisition processing device 10 to be TTL high-level trigger;

at this time, the slider 11 is rapidly moved to the contact switch B12 on the screw rod displacement table 2 from the contact switch a4 on the screw rod displacement table 2, at this time, the TTL trigger signal of the data acquisition and processing device 10 is changed to a high level, and the data acquisition and processing device 10 synchronously acquires the position signal of the grating ruler 1 and the light intensity signals output by the photoelectric detection modules 8 corresponding to different measurement positions;

step three: the time that the sliding block 11 is rapidly moved to the contact switch B12 on the screw rod displacement table 2 by the contact switch A4 on the screw rod displacement table 2 is completed within 3-5 seconds, the moving speed is increased, the signal to noise ratio of the collected square wave signals can be improved, when the sliding block 11 contacts the contact switch B12, the TTL trigger signal of the collection processing device 10 is changed into low level, and the data collection process is finished; and processing the data;

the data processing step comprises:

(d) confirming the time sequence of the position signal of the grating ruler 1 and the light intensity signal output by the photoelectric detection module 8 by the TTL trigger signals provided by the contact switch A4 and the contact switch B12;

(e) confirming the single peak position of the light intensity signal output by the photoelectric detection module 8;

(f) comprehensively analyzing the results obtained from the a and the b and the position signal of the grating ruler 1 to obtain a complete space measurement position result;

step four: and within the wavelength range of 600 nm-1100 nm, adjusting the light source 5 to output 5-10 quasi-monochromatic lights with different wavelengths, and repeating the second step to the fourth step. And (4) calculating the average value of the multiple measurement results, and finishing the calibration work of the electronic temperature measurement position.

While the embodiments of the present invention have been described in detail, the present invention is not limited to the above-described examples, and various changes can be made without departing from the spirit of the present invention within the knowledge of those skilled in the art.