RU2369999C1 - Laser positioner for x-ray emitter - Google Patents

Abstract

FIELD: physics.

SUBSTANCE: invention can be used for aligning an X-ray emitter with respect to an object. The laser positioner has a first mirror, mounted at an angle of 45° to the axis of the X-ray beam at the point of intersection of the axis of the X-ray beam and an axis, parallel to the longitudinal axis of the X-ray emitter and passing at a certain distance from the focus of the X-ray tube, a laser range-finder and a television system, consisting of a television camera based on a CCD matrix, a lens and a monitor, situated outside the exposure zone of the X-ray beam. In front of the lens of the television camera, there is a narrow-bandpass filter, bandpass of which coincides with the wavelength of the laser, used in the positioner for illuminating the object. The axis of the laser is parallel to the longitudinal axis of the X-ray emitter and passes through the centre of the first mirror, a rotor with a central axial opening, lying on the axis of the laser between the laser and the first mirror. A semi-transparent mirror and a second mirror are mounted in series on the surface of the rotor, perpendicular the axis of the laser and facing the first mirror, along one of its radii.

EFFECT: higher degree of visualisation of zones on an object exposed to X-rays, as well as easier adjustment of ring-shaped laser matrix.

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Description

The invention relates to the field of non-destructive testing of objects using x-ray radiation.

A known laser centralizer for an x-ray emitter, comprising a housing with a laser located in it, whose optical axis is parallel to the longitudinal axis of the x-ray emitter, two mirrors is a first mirror made of plexiglass and mounted at the intersection of the optical axes of the laser and x-ray beams perpendicular to the plane formed by them and directing them to the object is laser beams, concentric axes of the x-ray beam, a second mirror made translucent and mounted on the laser axis between it and the first with a glass perpendicular to the plane formed by the axes of the x-ray and laser beams, a television system consisting of a CCD matrix and a video monitor, the lens axis of the CCD matrix passes through the intersection point of the second mirror with the laser axis perpendicular to it, and the ring laser matrix installed symmetrically with respect to the laser axis perpendicular to it between the laser and the second mirror, a narrow-band light filter, the passband of which coincides with the laser radiation wavelength, installed in front of the TV lens system, to measure the distance to the x-ray emitter, a laser range finder is used, which is installed in the centralizer body, the beam of which propagates with the first mirror in the direction coinciding with the axis of the x-ray beam, and forms a laser spot on the object whose position coincides with the point of intersection of the object with the axis x-ray beam, the axis of the ring matrix lasers in the planes formed by the laser axes and the laser axis of the long-range system, are inclined to the laser axis of the rangefinder at angles α / 2, where α - the radiation angle of the x-ray emitter, converge at one point at a distance B from the matrix body on the laser axis of the range finder, located at a distance A from the point of intersection of the first mirror with the axis of the x-ray beam, equal to the distance from this point to the focus of the x-ray tube along the x-ray axis, and after reflection, the first mirrors propagate in the form of a conical beam of N rays, where N is the number of ring matrix lasers that form on the surface of the object a ring structure of N spots, symmetric with respect to the center ceiling elements spot formed on the object and the laser range finder, the diameter of this structure coincides with the size of the object area, transmission X-ray radiation [1].

The disadvantage of this invention is the difficulty of alignment of the annular matrix of the lasers, as well as the negative effect of the second translucent mirror on the operation of the laser rangefinder, which substantially depends on the presence of reflective translucent surfaces on the laser path. In addition, the rangefinder laser is periodically turned off during the measurement process to save power supply, which interferes with its observation when the centralizer is pointed at the object.

The purpose of the invention is the elimination of these disadvantages.

To do this, in a centralizer containing a housing in which the first mirror is located, set at an angle of 45 ° to the x-ray axis at the point of intersection of the x-ray axis and the axis parallel to the longitudinal axis of the x-ray emitter and passing at a distance A from the focus of the x-ray tube, a laser range finder and a television system consisting of a camera based on a CCD matrix, a lens and a monitor mounted outside the area of the x-ray beam, the optical axis of the laser rangefinder and the lens of the television camera of the ionization system are parallel to each other and the axis of the x-ray beam, and a narrow-band filter is installed in front of the camera lens, the passband of which coincides with the wavelength of the laser used in the centralizer to illuminate the object, while the laser axis is parallel to the longitudinal axis of the x-ray emitter and passes through the center of the first mirror, a rotor with a central axial hole located on the axis of the laser between it and the first mirror, on the surface of the rotor perpendicular to the axis of the laser and facing the first mirror, along th of its radii sequentially installed semitransparent mirror disposed on the laser axis at an angle of 45 ° to the axis, the second mirror installed at a distance R from the center of the semitransparent mirror at an angle

к оси лазера, где α - угол расхождения рентгеновского пучка, плоскости полупрозрачного зеркала и второго зеркала перпендикулярны плоскости, проходящей через ось лазера перпендикулярно плоскости, образованной осями лазера и рентгеновского пучка, центр полупрозрачного зеркала находится от центра первого зеркала на расстоянии С=А+В, где А - расстояние от фокуса рентгеновской трубки до центра первого зеркала,

, ротор приводится в движение от электрического или иного привода с частотой f≤10 Гц.

to the laser axis, where α is the angle of divergence of the X-ray beam, the plane of the translucent mirror and the second mirror are perpendicular to the plane passing through the laser axis perpendicular to the plane formed by the axes of the laser and the X-ray beam, the center of the translucent mirror is located at a distance C = A + B from the center of the first mirror where A is the distance from the focus of the x-ray tube to the center of the first mirror,

, the rotor is driven by an electric or other drive with a frequency f≤10 Hz.

The device diagram is shown in figure 1.

к оси лазера.The centralizer comprises a housing 2 mounted on the x-ray emitter 1. In the housing 2 there is a laser 9, the axis of which is parallel to the longitudinal axis of the x-ray emitter and passes at a distance A from the focus of the x-ray tube through the center of the first mirror 3. Between the laser 9 and the first mirror 3 on the laser axis a rotor 4 is installed with a central hole, on the surface of which facing the first mirror 3, a translucent mirror is sequentially mounted on the axis of the laser 9 at an angle of 45 ° to it, as well as a second mirror 5 installed at an angle

to the axis of the laser.

The rotor is rotated relative to the axis of the laser 9 using an electric drive consisting, for example, of a friction clutch 7 and a motor 8. A laser rangefinder 10 and a television system are also installed on the housing 2, which is turned on by the camera 11 with a lens 12, a CCD matrix 13 and a monitor fourteen.

The centralizer works as follows - part of the laser 9 rays passes through a translucent mirror 6, after reflection from the first mirror 3 they propagate in the direction coinciding with the axis of the x-ray beam, and forms a bright point on the surface of the object 15, the position of which coincides with the point of intersection of the object with the x-ray axis .

The second part of the laser radiation 9 is directed to the second mirror 5 and, after reflection from it, is directed at an angle α / 2 to the laser axis to a point located at a distance A from the center of the first mirror 3.

When the rotor 4 rotates, the rays of the laser 9 reflected from the second mirror 5 form the surface of the cone with an angle at the apex α, whose axis coincides with the axis of the laser, and whose vertex is on the axis of the laser 9 at a distance A from the center of the first mirror 3.

After reflection from the first mirror 3, these rays propagate coaxially with the axis of the x-ray beam and form a bright ring on the object, the diameter of which is equal to the diameter of the portion of the object illuminated by the x-ray beam, and which is observed on the monitor screen 4.

At a rotation frequency of f≥10 Hz, the image of the ring is visually perceived as fused.

выбран с учетом геометрических соотношений, показанных на фиг.2.The angle of inclination φ of the second translucent mirror 6 to the axis of the laser beam

selected taking into account the geometric relationships shown in figure 2.

Таким образом, расстояние от второго полупрозрачного зеркала до лазера определяется углом расхождения рентгеновского пучка и конструктивным параметром В, что позволяет легко перестраивать геометрию пучка конических лучей при вращении ротора 4.From a right triangle OMK we have

Thus, the distance from the second translucent mirror to the laser is determined by the angle of divergence of the x-ray beam and structural parameter B, which makes it easy to reconstruct the geometry of the beam of conical rays during rotation of the rotor 4.

It is clear that in this case, the angle of inclination φ of the second translucent mirror has a single value equal to

откуда

.Indeed, from a right triangle OMK we have

where from

.

Considering the angles adjacent to the OD axis, we obtain 2γ = 180 ° -β, whence

.In view of (2), we obtain

.

From the rectangle OCD we have finally

по определению) и перпендикулярна СО, направление которого совпадает с радиусом ротора 4. По известному закону отражения геометрической оптики нормаль MN к поверхности второго полупрозрачного зеркала 6 должна совпадать с биссектрисой угла КМО (угол падения равен углу отражения).Note that the hypotenuse of the triangle OCD, which coincides with the surface of the translucent mirror 6, is drawn through the point O of intersection of the line PO (side of the OPC angle equal to

by definition) and is perpendicular to the CO whose direction coincides with the radius of the rotor 4. According to the well-known law of reflection of geometric optics, the normal MN to the surface of the second translucent mirror 6 must coincide with the bisector of the CMO angle (the angle of incidence is equal to the angle of reflection).

The centralizer is used as follows. Turn on the laser 9 and rotor drive 4 and, observing on the monitor screen 14 the image of the object simultaneously with the images of the ring structure formed on it with a bright dot in the center of the ring, combine this structure with the desired area of the object, moving the x-ray emitter 1 together with the housing 2 relative to the object 15 After completing the procedure of pointing the emitter to the object, the distance of the laser range finder 10 is measured, the necessary transillumination mode is selected, and the radiographic film is exposed.

Literature

1. RF patent N 2293453, Laser centralizer.

Claims (1)

Laser centralizer for an X-ray emitter, in which the first mirror is located, set at an angle of 45 ° to the axis of the X-ray beam at the point of intersection of the x-ray axis and the axis parallel to the longitudinal axis of the x-ray emitter and passing at a distance A from the focus of the x-ray tube, a laser rangefinder and a television system consisting of a camera based on a CCD matrix, a lens and a monitor mounted outside the area of the x-ray beam, the optical axis of the laser rangefinder and the telephoto lens measures of the television system are parallel to each other and to the axis of the x-ray beam, and a narrow-band filter is installed in front of the camera lens, the passband of which coincides with the wavelength of the laser used in the centralizer to illuminate the object, while the laser axis is parallel to the longitudinal axis of the x-ray emitter and passes through the center of the first mirror , a rotor with a central axial hole located on the laser axis between it and the first mirror, on the surface of the rotor perpendicular to the laser axis and facing the first mirrors y, along one of its radii, a translucent mirror is placed in series, located on the laser axis at an angle of 45 ° to the axis, a second mirror installed at a distance R from the center of the translucent mirror at an angle

to the laser axis
where α is the angle of divergence of the x-ray beam, the plane of the translucent mirror and the second mirror are perpendicular to the plane passing through the laser axis perpendicular to the plane formed by the axes of the laser and the x-ray beam, the center of the translucent mirror is located from the center of the first mirror at a distance C = A + B,
where A is the distance from the focus of the x-ray tube to the center of the first mirror;

,
the rotor is driven by an electric or other drive with a frequency f≥10 Hz.

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