JP2011185674A - Test beam generation device, and nondestructive testing device and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a test beam generation device for efficiently and nondestructively testing an internal state of a concrete structure. <P>SOLUTION: The test beam generation device includes: a femtosecond laser generator 1a for generating femtosecond laser pulses; a movable mirror 1b for alternatively emitting femtosecond laser pulses entering from the femtosecond laser generator 1a in a first direction or a second direction; a photoconductive antenna 1j for converting femtosecond laser pulses emitted in a first direction by the movable mirror 1b to terahertz light before emitting to the outside as a test beam; an ion beam generator 1n for generating an ion beam of a specific element based on the femtosecond laser pulses emitted in a second direction by the movable mirror 1b; and a neutron ray generator 1s for generating neutron rays based on the ion beam entering from the electron beam generator 1n for emitting to the outside as the test beam. Thus, the test beam generation device can perform an efficient nondestructive test. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an inspection line generator, a non-destructive inspection device, and a method.

For example, Patent Document 1 below discloses an apparatus (grouting defect inspection apparatus) for inspecting a grout defect of a PC steel material. This grout defect inspection system utilizes the fact that the scattering state of neutron beams differs between concrete constituents (aggregates, iron, etc.) and cavities with grout defects, and neutron beams penetrate the concrete structure. Grout defects are discriminated by detecting the thermal neutrons obtained. That is, this grout defect inspection apparatus discriminates grout defects in PC steel based on the dose of thermal neutrons detected on the side opposite to the neutron source.
As a nondestructive inspection technique using a neutron beam, there is a three-dimensional moving body visualization measuring apparatus and method shown in Patent Document 2 in addition to the technique of Patent Document 1, and this three-dimensional moving body visualization measuring apparatus and method are also included. It uses the neutron scattering phenomenon.

JP 2001-041908 A JP 2007-333663 A

  By the way, the grout defect inspection apparatus is a kind of non-destructive inspection apparatus using a neutron beam. The scattering state of the neutron beam is composed of concrete constituents (such as aggregate and iron) and a hollow portion having a grout defect. Because it uses different things, it is not possible to nondestructively inspect the state of the reinforcing bars that are constituents of concrete.

  In addition, since the nondestructive inspection using a neutron beam has a relatively long inspection time, there is a problem that work efficiency is poor when nondestructive inspection is performed at a plurality of locations of a concrete structure. For example, a viaduct on a highway is a typical concrete structure, but since it is a concrete structure over a long distance, there are a large number of inspection points. Such a viaduct is subjected to nondestructive inspection using neutron beams. When it is used, it takes an enormous amount of time, so the development of an efficient nondestructive inspection method using neutrons is eagerly desired.

  This invention is made | formed in view of the situation mentioned above, and aims at carrying out the nondestructive inspection of the internal state of a concrete structure efficiently.

  In order to achieve the above object, in the present invention, as a first solution part for an inspection line generator, a femtosecond laser generator for generating a femtosecond laser pulse having a femtosecond pulse width, and the femtosecond laser Variable emission means for selectively emitting the femtosecond laser pulse incident from the generator in the first direction or the second direction, and the femtosecond laser pulse emitted in the first direction by the variable emission means for the terahertz light An ion beam generator for generating an ion beam of a predetermined element based on a femtosecond laser pulse emitted in the second direction by the variable emission means, and the ion A means for generating a neutron beam based on an ion beam incident from the line generator and emitting the neutron beam to the outside as an inspection line; To use.

  As the second solving means relating to the inspection line generating device, a means is adopted in which the above first solving means further comprises a coaxial means for coaxially coordinating the emission axis of the terahertz light and the emission axis of the neutron beam.

  As a third solving means relating to the inspection line generator, in the second solving means, the coaxial means reflects the terahertz light by a plurality of reflecting plates so that the emission axis of the lahertz light becomes the emission axis of the neutron beam. Adopting the means of coaxial.

  As a fourth solving means related to the inspection line generating device, in any of the first to third solving means, the light converting means is selected to pass the femtosecond laser pulse as guide light without converting it to terahertz light. Adopt a means of having a function.

  In the present invention, as the first solving means relating to the nondestructive inspection apparatus, the inspection line generating apparatus of any one of the first to fourth solving means and the terahertz light supplied from the inspection line generating apparatus or Irradiation means for irradiating the inspection object with neutron rays in a scanning manner and reflected light obtained by reflecting terahertz light by the inspection object or diffracted neutron radiation obtained by diffracting the neutron beam by the inspection object Detecting means according to the scanning position of the part, and of the reflected light or diffracted neutron beam detection signal inputted from the detecting means, the surface state at the scanning position of the inspection object based on the detection signal of the reflected light Data processing means for determining and calculating the lattice constant of the substance at the scanning position of the inspection object based on the detection signal of the diffracted neutron beam, and the surface state of the inspection object at each scanning position Rui employs the means of, for and a visualizing means for visualizing the surface state or the internal state of the inspection object based on the lattice constant of the material.

  Furthermore, in the present invention, as a first solving means related to the nondestructive inspection method, based on the optical inspection process for performing the nondestructive inspection of the surface state of the inspection object using terahertz light, and the inspection result of the optical inspection process A neutron beam is irradiated in a scanning manner to a portion that is recognized as being suspected of being damaged, and a diffracted neutron beam obtained by diffracting the neutron beam by the inspection object is detected. A means is adopted that includes a neutron inspection step for calculating a lattice constant of a substance, and a visualization step for visualizing the internal state of the inspection object based on the lattice constant of the substance obtained in the neutron inspection step.

  According to the inspection line generator according to the present invention, two inspection lines, that is, terahertz light or neutron rays are generated as inspection lines using a femtosecond laser pulse that is a single source, so that two inspection lines are generated. It is possible to make the device configuration of the nondestructive inspection device compact compared to the case where the nondestructive inspection device is configured by generating the same with an individual generator. Therefore, according to the present inspection line generator, a non-destructive inspection apparatus with good handleability can be configured, so that the internal state of the concrete structure can be efficiently inspected nondestructively.

It is a mimetic diagram showing composition of hybrid inspection line generator 1 concerning one embodiment of the present invention. It is a block diagram which shows the structure of the concrete inspection apparatus A which concerns on one Embodiment of this invention.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the hybrid inspection line generator 1 according to this embodiment includes a femtosecond laser generator 1a, a movable mirror 1b (variable emission means), fixed mirrors 1c to 1f, a neutron conduit 1g, a shutter 1h, and 1i. , A photoconductive antenna 1j (light converting means), an optical amplifier 1k, a condenser lens 1m, an ion beam generator 1n, a deflection magnet 1r, and a neutron beam generator 1s. The fixed mirrors 1c to 1e and the shutters 1h and 1i constitute coaxial means.

  Although details will be described later, the hybrid inspection line generator 1 has two operation modes. The first operation mode is a light emission mode in which terahertz light is emitted outside as an inspection line, and the second operation mode is a neutron emission mode in which a neutron pulse is emitted outside as an inspection line. FIG. 1 shows a state where the hybrid inspection line generator 1 is in the light emission mode, and the operation mode is changed from the light emission mode by moving the fixed mirror 1e and the shutters 1h and 1i from this state and removing them from the optical path. Switch to neutron emission mode.

  The terahertz light is an inspection line capable of inspecting the surface state (more precisely, the vicinity of the surface) of a concrete structure as an inspection object because the transmission performance with respect to concrete is weaker than that of a neutron pulse. On the other hand, the neutron pulse has a higher permeation performance with respect to concrete than X-rays. For example, the neutron pulse is an inspection line that can inspect the internal state of a concrete structure because it penetrates to a depth of about 10 cm. On the other hand, in the diagnosis of concrete, it is important to evaluate the corrosion state in the vicinity of the reinforcing bar. However, since the reinforcing bar is located at a depth of 10 cm at most from the surface, a nondestructive inspection using a neutron beam is realistic.

The femtosecond laser generator 1a is a laser generator that generates femtosecond laser pulses having a pulse width on the order of femtoseconds ( ^10-15 seconds), for example, several femtoseconds to several hundred femtoseconds. As is well known, the femtosecond laser pulse is a laser beam with extremely strong intensity because light energy is compressed in a short time. The femtosecond laser generator 1a emits the femtosecond laser pulse generated by itself toward the movable mirror 1b.

  The movable mirror 1b is a variable emitting unit that alternatively emits the femtosecond laser pulse incident from the femtosecond laser generator 1a in the first direction or the second direction. The movable mirror 1b is, for example, a circular flat reflector and rotates around a rotation axis provided on an extension line of the central axis so that a femtosecond laser pulse incident from the femtosecond laser generator 1a is incident. The light is reflected in the direction of the fixed mirror 1c (first direction) that is perpendicular to the direction or in the direction of the fixed mirror 1f (second direction) that is opposite to the first direction.

  The fixed mirror 1c is a reflecting mirror that reflects the femtosecond laser pulse incident from the movable mirror 1b toward the fixed mirror 1d. The fixed mirror 1d is a reflecting mirror that reflects the femtosecond laser pulse incident from the fixed mirror 1c toward the fixed mirror 1e. The fixed mirror 1e is a reflecting mirror that reflects the femtosecond laser pulse incident from the movable mirror 1c toward the opening center of the shutter 1h. The fixed mirror 1e is provided between the neutron beam generator 1s and the shutter 1h in the light emission mode as shown in FIG. 1, but is moved and removed from the optical path of the terahertz light in the neutron emission mode. The fixed mirror 1f is a reflecting mirror that reflects the femtosecond laser pulse incident from the movable mirror 1b toward the input end of the optical amplifier 1k.

  The neutron conduit 1g is a passage through which a neutron beam incident from the neutron beam generator 1s passes. This neutron conduit 1g is based on the principle that neutrons are totally reflected at a small incident angle like light. For example, the surface is polished and has high smoothness on a glass having high smoothness, and is coherent with neutrons such as nickel. A neutron beam is guided in a desired direction using a reflection boundary formed by forming a metal film having a large scattering cross section and a small absorption to a predetermined thickness. Such a neutron conduit 1g is for guiding a neutron beam as described above, and has no effect on the femtosecond laser pulse incident through the shutter 1h by being reflected by the fixed mirror 1e. Pass without.

  The shutter 1h is provided at the incident end of such a neutron conduit 1g, and turns on / off the passage of femtosecond laser pulses. The shutter 1i is provided at the exit end of the neutron conduit 1g and turns on / off the passage of femtosecond laser pulses in the same manner as the shutter 1h. The shutters 1h and 1i are of a known rotary type, and are of a type in which an opening through which a femtosecond laser pulse passes concentrically extends from the center.

  Such shutters 1h and 1i are provided at the entrance end and the exit end of the neutron conduit 1g so that the center of the opening coincides with the center of the neutron conduit 1g, and the optical axis of the femtosecond laser pulse is used as a neutron generator. This is intended to coincide with the center line of the neutron pulse incident on the neutron conduit 1g from 1s. Such shutters 1h and 1i are provided between the neutron beam generator 1s and the neutron conduit 1g as shown in FIG. 1 in the light emission mode, but move in the same manner as the fixed mirror 1e described above in the neutron emission mode. Then, it is removed from the optical path of the terahertz light.

  The photoconductive antenna 1j is a light converting means that converts the femtosecond laser pulse emitted in the first direction into pulsed terahertz light and emits it as an inspection line to the outside. The photoconductive antenna 1j converts the femtosecond laser pulse into pulsed terahertz light by allowing the femtosecond laser pulse to pass between the two electrodes to which a predetermined bias voltage is applied while being balanced. Note that the optical conversion means for converting the femtosecond laser pulse into pulsed terahertz light may be of a system other than the photoconductive antenna 1j.

  The optical amplifier 1k optically amplifies the femtosecond laser pulse incident from the fixed mirror 1f, and is, for example, an optical amplifier using an optical fiber or a semiconductor optical amplifier. This optical amplifier 1k emits an optically amplified femtosecond laser pulse toward the optical axis of the condenser lens 1m. The condensing lens 1m is a convex lens that condenses the femtosecond laser pulse so as to focus on the surface of the target provided in the ion beam generator 1n.

  The ion beam generator 1n generates an ion beam (ion pulse) of a predetermined element (hydrogen H, helium He, etc.) by irradiating the target with the femtosecond laser pulse incident from the optical amplifier 1k. The ion beam generator 1n emits an ion pulse generated by the ion beam generator 1n toward the neutron beam generator 1s. The deflection magnet 1r is provided in the ion pulse passage between the ion beam generator 1n and the neutron beam generator 1s, and deflects the ion pulse by applying a magnetic field to the ion pulse. That is, the deflection magnet 1r deflects the ion pulse so as to irradiate a predetermined position of the target provided in the neutron beam generator 1s.

  The neutron beam generator 1s generates pulsed thermal neutrons or epithermal neutrons (neutron pulses) by irradiating a predetermined target with an ion pulse incident from the ion beam generator 1n. The neutron beam generator 1s emits a neutron pulse generated by itself as an inspection line toward the incident end of the neutron conduit 1g.

Next, the concrete inspection apparatus A according to this embodiment will be described with reference to FIG.
As shown in FIG. 2, the concrete inspection apparatus A includes a hybrid inspection line generator 1, an inspection line irradiation unit 2 (irradiation unit), an inspection line detection unit 3 (detection unit), and a data processing unit 4 (data processing). Means and visualization means).

  Such a concrete inspection apparatus A includes a light inspection mode (first inspection mode) in which the hybrid inspection line generator 1 is in a light emission mode and a neutron inspection mode (second inspection) in which the hybrid inspection line generator 1 is in a neutron emission mode. Mode) and two operation modes.

  That is, the concrete inspection apparatus A reflects terahertz light (pulse light) generated as an inspection line by the hybrid inspection line generator 1 in the light emission mode, and the hybrid inspection line generator 1 generates an inspection line in the neutron emission mode. It uses neutron pulse diffraction and performs nondestructive inspection of the surface state of a concrete structure (inspection object) with terahertz light and the internal state of the concrete structure with neutron pulse. The internal state of the concrete structure is, for example, a state of a specific substance, for example, a reinforcing bar, among a plurality of substances (aggregate, reinforcing bar, concrete, etc.) constituting the concrete structure.

  The concrete structure is, for example, a concrete bridge, building, or tank. As such a concrete structure, for example, there is a viaduct R (road bridge) for an expressway as shown. The viaduct R is a concrete structure composed of a floor slab r1 and a bridge pier r2 that supports the floor slab r1 at a height of several meters from the ground. In such a viaduct R, spraying materials such as anti-freezing agents and snow melting agents are spread on the roads constructed on the floor slab r1, and the deterioration of the floor slab r1 due to the effect of such spraying material. For example, there is a concern about corrosion (rust generation) of the reinforcing bar r3 embedded in the floor slab r1.

  The hybrid inspection line generator 1 emits the terahertz light or neutron pulse to the inspection line irradiation unit 2. The inspection line irradiation unit 2 irradiates the lower surface (plane) of the floor slab r1 with the terahertz light or neutron pulse incident from the hybrid inspection line generator 1 at a predetermined angle. The inspection line irradiation unit 2 detects the emission timing t1 of the neutron pulse, and outputs an emission detection signal indicating the emission timing t1 to the data processing unit 4. For example, the inspection line irradiation unit 2 detects the emission timing t1 of the neutron pulse by capturing the gamma ray (γ ray) generated by the transmission of the neutron pulse through the predetermined member.

  The inspection line detection unit 3 includes a plurality of detectors (four as an example in FIG. 1) arranged at regular intervals as shown. The inspection line detector 3 receives the reflected terahertz light reflected by the floor slab r1 with each detector and detects the diffracted neutron pulse diffracted by the floor slab r1 with each detector. . The inspection line detection unit 3 outputs a light reception signal of the reflected terahertz light to the data processing unit 4 and outputs an incident detection signal indicating the detection timing t2 of the diffracted neutron pulse to the data processing unit 4.

  The data processing unit 4 determines the surface state of the floor slab r1 and the inside thereof based on the received light signal of the reflected terahertz light, the emission detection signal input from the inspection line irradiation unit 2, and the incident detection signal input from the inspection line detection unit 3. Assess the condition. That is, the data processing unit 4 evaluates the surface state of the floor slab r1 based on the received light signal, and evaluates the internal state of the floor slab r1 based on the emission detection signal and the incident detection signal.

  This internal state is evaluated by calculating the lattice constant d of the substance at each diffraction site of the floor slab r1 by introducing the time difference ΔT between the emission timing t1 and the incident timing t2 into the lattice constant calculation formula. Is called. The above equation for calculating the lattice constant is based on the well-known Bragg equation relating to the diffraction phenomenon. The data processing unit 4 generates an inspection image in which the internal state of the floor slab r1 is visualized two-dimensionally based on the lattice constant d at each diffraction site obtained in this way.

  Next, a nondestructive inspection method using such a concrete inspection apparatus A will be described in detail.

  In the non-destructive inspection of the floor slab r1 using the concrete inspection apparatus A, an optical inspection process for non-destructively inspecting the surface state of the floor slab r1 using terahertz light in a state where the concrete inspection apparatus A is set to the optical inspection mode; The slab r1, which was found to be suspected of being damaged based on the inspection result of the optical inspection process, was irradiated with a neutron pulse in a state where the concrete inspection apparatus A was set to the neutron inspection mode, and the internal state was not changed. A neutron inspection process for destructive inspection is performed. When the neutron inspection process is completed, the concrete inspection apparatus A determines the internal state of the floor slab r1 (arrangement and corrosion state of the rebar r3 etc.) based on the inspection result (material lattice constant) obtained in the neutron inspection process. A visualization process for visualizing the inspection image is performed.

  In the optical inspection process, the inspection operator first sets the concrete inspection apparatus A to the optical inspection mode. In this light inspection mode, the hybrid inspection line generator 1 is set to the light emission mode. That is, in the hybrid inspection line generator 1, the rotating state of the movable mirror 1b is set so as to reflect the femtosecond laser incident from the femtosecond laser generator 1a in the direction of the fixed mirror 1c (first direction). As a result, terahertz light is emitted to the inspection line irradiation unit 2 as an inspection line.

  Then, the inspection line irradiation unit 2 irradiates the surface of the floor slab r1 in a scanning manner using terahertz light as an inspection line. As a result, the reflected terahertz light reflected by the irradiation region of the terahertz light is sequentially received by the inspection line detection unit 3. Since the inspection line detection unit 3 sequentially outputs the light reception signal of the reflected terahertz to the data processing unit 4, an optical inspection image indicating the surface state of the floor slab r1 is generated by the data processing unit 4 as an inspection result. .

  The inspection operator confirms a portion that is suspected of being damaged, such as a scratch or discoloration on the surface of the floor slab r1, from the optical inspection image output from the concrete inspection apparatus A (data processing unit 4) in the optical inspection process. In the neutron inspection process, the inspection operator switches the concrete inspection apparatus A from the optical inspection mode to the neutron inspection mode, and the neutron pulse is irradiated to a limited region including a portion suspected of being damaged. The direction of the inspection line irradiation unit 2 is adjusted.

  In the neutron inspection mode, the hybrid inspection line generator 1 is set to the neutron emission mode. That is, in the hybrid inspection line generator 1, the rotational state of the movable mirror 1b is set so as to reflect the femtosecond laser incident from the femtosecond laser generator 1a in the direction of the fixed mirror 1f (second direction). As a result, a neutron pulse is emitted to the inspection line irradiation unit 2 as an inspection line. The inspection line irradiating unit 2 irradiates a region in the vicinity of a portion suspected of damage to the floor slab r1 using a neutron pulse as an inspection line. As a result, the diffracted neutron pulse generated in the irradiation region of the neutron pulse (the surface and inside of the floor slab r1) is detected by the inspection line detection unit 3.

  Then, the data processing unit 4 calculates a time difference ΔT between the emission timing t1 and the incident timing t2 based on the emission detection signal input from the inspection line irradiation unit 2 and the incident detection signal input from the inspection line detection unit 3. By introducing this time difference ΔT into the lattice constant calculation formula, the lattice constant d of the substance at each diffraction site of the floor slab r1 is calculated, and the lattice constant d (lattice constant group) of each diffraction site is calculated in the neutron inspection step. Output to the outside as the inspection result.

  Further, the data processing unit 4 generates a neutron inspection image showing the internal state of the floor slab r1 as a result of the visualization step based on the lattice constant d (lattice constant group). The lattice constant calculation formula is well known and will not be described in detail. However, it is based on the Bragg equation indicating the diffraction phenomenon, and the neutron wavelength in the Bragg equation is given by the well-known de Broglie equation. At the same time, the momentum of the neutrons in the de Broglie's equation is given by the neutron velocity, the mass and the speed of light which are geometrically determined from the time difference ΔT.

  For example, when the reinforcing bar r3 is present in the irradiation region of the neutron pulse, since the reinforcing bar r3 and the surrounding cement or aggregate have different crystal structures, the lattice constant d is naturally different between the reinforcing bar r3 and the surrounding portion. Further, when the rebar r3 is corroded and rust is generated around the rebar r3, this rust is an oxide of iron, and therefore has a crystal structure different from that of the rebar r3. Therefore, the lattice constant d is equal to the rebar s1. Is different. Therefore, the lattice constant d (lattice constant group) is information indicating the internal state of the floor slab r1.

  As described above, the hybrid inspection line generator 1 according to the present embodiment has two operation modes of the light emission mode and the neutron emission mode. That is, the hybrid inspection line generator 1 selectively emits terahertz light or a neutron pulse as an inspection line to the inspection line irradiation unit 2 by switching the rotation state of the movable mirror 1b according to the operation mode.

  Therefore, according to the hybrid inspection line generator 1 according to the present embodiment, two different inspection lines can be generated using the femtosecond laser that is a single source, so that the two inspection lines are individually It is possible to make the apparatus configuration of the concrete inspection apparatus A compact as compared with the case where it is generated by the generator. Therefore, according to this hybrid inspection line generator 1, since the concrete inspection apparatus A is easy to handle, the internal state of the floor slab r1 can be efficiently inspected nondestructively.

  Also, according to the hybrid inspection line generator 1, since two types of inspection lines (terahertz light and neutron pulse) are on the same exit axis by the coaxial means, compared to the case where they are configured as individual exit axes. The handling property of the concrete inspection apparatus A is good, so that the internal state of the floor slab r1 can be efficiently inspected nondestructively.

  Moreover, according to the concrete inspection apparatus A provided with such a hybrid inspection line generator 1, it is possible to perform the neutron inspection process after the optical inspection process, and thus the neutron inspection process for the entire lower surface of the floor slab r1. It is possible to inspect the internal state of the floor slab r1 more efficiently than in the case of performing the destructive inspection.

  In addition, according to the nondestructive inspection method using such a concrete inspection apparatus A, since the neutron inspection process is performed after the optical inspection process, it is only necessary to perform the optical inspection process only in the vicinity of a portion suspected of being damaged. The internal state of the floor slab r1 can be more efficiently nondestructively inspected than when the neutron inspection process is performed on the entire lower surface of the floor slab r1.

In addition, this invention is not limited to the said embodiment, For example, the following modifications can be considered.
(1) In the above embodiment, the viaduct R, which is one of the concrete structures, is an inspection object, but the present invention is not limited to this. The inspection object may be any object as long as it reflects terahertz light and diffracts neutrons.

(2) Although the concrete inspection apparatus A irradiates the floor slab r1 with terahertz light or neutron pulse as inspection light, these inspection lines are not visible to the inspection operator. In view of such an inspection situation, for example, by temporarily stopping application of a bias voltage applied between two electrodes constituting the photoconductive antenna 1j, the function of the photoconductive antenna 1j is temporarily stopped, Thus, by irradiating the floor slab r1 from the inspection line irradiation unit 2 as a guide light with a femtosecond laser visible to the inspection operator, the inspection line on the surface of the floor slab r1 in the optical inspection process and / or neutron inspection process It is conceivable to make it possible to confirm the irradiation position in advance.

(3) In the hybrid inspection line generator 1, the photoconductive antenna 1j is provided at the rear stage, but the present invention is not limited to this. For example, the photoconductive antenna 1j may be provided at any position in the optical path of the femtosecond laser from the movable mirror 1b to the fixed mirror 1c to the fixed mirror 1d to the fixed mirror 1f or between the fixed mirror e and the neutron conduit 1g. .

(4) In the hybrid inspection line generator 1, the coaxial means is constituted by the fixed mirrors 1c to 1e and the shutters 1h and 1i, but the present invention is not limited to this. For example, other optical waveguides may be employed instead of the fixed mirrors 1c and 1d. As another optical waveguide, for example, an optical fiber can be considered.

  A ... Concrete inspection device (non-destructive inspection device), R ... bypass, r1 ... slab, r2 ... pier, r3 ... rebar, 1 ... hybrid inspection line generator, 1a ... femtosecond laser generator, 1b ... movable mirror ( (Variable emission means), 1c to 1e, fixed mirror (coaxial means), 1f, fixed mirror, 1g, neutron conduit, 1h, 1i, shutter (coaxial means), 1j, photoconductive antenna (light converting means), 1k DESCRIPTION OF SYMBOLS Optical amplifier, 1m ... Condensing lens, 1n ... Ion beam generator, 1r ... Deflection magnet, 1s ... Neutron beam generator, 2 ... Inspection line irradiation part (irradiation means), 3 ... Inspection line detection part (detection means) 4, data processing unit (data processing means, visualization means)

Claims (6)

A femtosecond laser generator for generating a femtosecond laser pulse having a femtosecond pulse width;
Variable emission means for selectively emitting the femtosecond laser pulse incident from the femtosecond laser generator in the first direction or the second direction;
A light converting means for converting the femtosecond laser pulse emitted in the first direction by the variable emitting means into terahertz light and emitting the same as an inspection line;
An ion beam generator for generating an ion beam of a predetermined element based on the femtosecond laser pulse emitted in the second direction by the variable emission means;
A neutron beam generator that generates a neutron beam based on an ion beam incident from the ion beam generator and emits the neutron beam as an inspection line.   2. The inspection line generator according to claim 1, further comprising coaxial means for coaxially cohering the output axis of the terahertz light and the output axis of the neutron beam.   The inspection line generator according to claim 1 or 2, wherein the coaxial means makes the emission axis of the lahertz light coaxial with the emission axis of the neutron beam by reflecting the terahertz light with a plurality of reflectors.   The inspection line generator according to any one of claims 1 to 3, wherein the light conversion means has a selection function of allowing the femtosecond laser pulse to pass as guide light without being converted into terahertz light. The inspection line generator according to any one of claims 1 to 4,
An irradiation means for irradiating the inspection target with terahertz light or neutron beam supplied from the inspection line generator;
Detecting means for detecting reflected light obtained by reflecting terahertz light by the inspection object or diffracted neutron beam obtained by diffracting the neutron beam by the inspection object according to the scanning position of the irradiation unit;
Of the detection signal of the reflected light or diffracted neutron beam input from the detection means, the surface state at the scanning position of the inspection object is determined based on the detection signal of the reflected light, and the inspection is performed based on the detection signal of the diffracted neutron beam Data processing means for calculating the lattice constant of the substance at the scanning position of the object;
A non-destructive inspection apparatus comprising: a visualization unit that visualizes a surface state or an internal state of an inspection object based on a surface state of the inspection object or a lattice constant of the substance at each scanning position. An optical inspection process for nondestructive inspection of the surface state of the inspection object using terahertz light;
Irradiating a neutron beam in a scanning manner to a part that is recognized as being suspected of being damaged based on the inspection result of the optical inspection process, and detecting a diffracted neutron beam obtained by diffracting the neutron beam by an inspection object By the neutron inspection process for calculating the lattice constant of the substance at each scanning position of the inspection object,
And a visualization step of visualizing the internal state of the inspection object based on the lattice constant of the substance obtained in the neutron inspection step.

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