X-ray microscope

 

X-ray microscope contains extended x-ray source, and means for placing the investigated object 3 and the means for registering and located between the x-ray capillary lens. The channels last diverge in the direction of the means for registration. Means for placing the investigated object is set between the extended x-ray source and a lower end of the x-ray capillary lens. Feature of the device is that the walls of the channels (14, 16) transportation of radiation are coated or made of a material absorbing or scattering x-ray radiation, and have the shape of a side surface or a truncated cone or pyramid, or cylinder, or prism. Given this choice of material is eliminated the phenomenon of total external reflection, and the straightness of the longitudinal axes of the channels ensures their work as collimators. Therefore, the channels capture radiation only those fragments of the studied object 3, which are exactly opposite of their inputs. In comparison with the known device eliminates the possibility of capturing radiation entering the channel 18 at angles from zero to the critical anglesesimi the possibilities of reducing the input dimension of the channels. The possibility of using extended x-ray source can significantly reduce the exposure time while reducing power x-ray tube. 6 silt.

The technical field

The invention relates to a projection microscopy with the use of radiation techniques, and more particularly to means for obtaining increased shadow projection of the object, including its internal structure, using x-rays.

Prior art

Known x-ray microscope, which allows to obtain an image of the internal structure of objects. The effect of such a microscope is based on the principle of shadow projection of the object in a divergent beam of x-rays emitted by a point source (Encyclopedic dictionary of electronics, Moscow, Soviet encyclopedia, 1991, S. 478. [1]). This microscope has been called the shadow or projection. Projection microscope normally contains microfocus x-ray tube, a chamber for the accommodation of a measured object and recording tool. The resolution of projection x-ray microscope is the higher, the less RAS x-ray tube focal spot of 0.1-1 μm in diameter [1]. To further reduce the effective size of the source used stopped down (Physical encyclopedic dictionary, Moscow, Soviet encyclopedia, 1984, S. 639 [2]).

However, reducing the size of the source or when stopped down its intensity becomes insufficient to provide acceptable contrast enhanced image. Overcoming this drawback requires a substantial increase in the exposure time. The increase of the source size to increase its effective intensity leads to a blurring of the resulting image and reduce the resolution.

With the creation of x-ray capillary optics total external reflection, the opportunity arose for use in x-ray microscopes extended (commensurate with the object under study x-ray sources. In such microscopes camera with the object under study is placed between the extended x-ray source and the input face of the x-ray lens with channels diverging in the direction of the means for recording the image (international application PCT/EN 94/00189, international publication WO 96/01991 from 25.01.96 [3]). Specifically in the specified source described the use of a conical x-ray lens does not affect the resolution of these microscopes, because it corresponds to the fragment size of the object falls within the field of view of a single channel of the x-ray capillary lens. X-ray microscope above structure is closest to the offer.

However, with decreasing diameter of the individual channels to the level achieved with modern technology in monolithic and, in particular, the integral lens (U.S. patent No. 6271534, publ. 07.08.2001 [4]), the size of the entrance opening of a single channel of the x-ray lens ceases to be a determining factor. This is because the size ofmentioned field of view of a single channel lens is of the order

where d is the inlet diameter of the individual channel

L is the distance between the object and the channel input x-ray lenses,

withcritical angle of total external reflection from the material of the walls of the channels.

At small diameters d and low energy radiation used, in particular, in the study of biological objects, when the angleccan be up to 10-2the radian, the second term in the above expression (1) stanum = 2·l·10-3m·10-2= 2Lc.

As a result, the improvement of manufacturing x-ray lenses is not possible to improve the accuracy performance of x-ray microscopes described known construction using extended sources.

Disclosure of inventions

The present invention aims to obtain a technical result consists in increasing the resolution of the projection microscope using x-ray radiation, by reducing the diameter of the channels used capillary lens while maintaining the possibility of using long (including the superior dimensions of the investigated object) source while excluding the dependence of the resolution on the energy of the applied radiation. The above technical result combined with low exposure times.

To achieve the technical result of the proposed x-ray microscope, as mentioned above, the closest known from the patent [3], contains an extended x-ray source, and means for placing the investigated object and the means for registering and located mereidth for registration. The tool for placement of the investigated object is set between the extended x-ray source and the input (lower) end of the x-ray capillary lens.

Unlike most similar known devices in the proposed x-ray microscope walls of the channels of x-ray capillary lenses have an inside coating or made of a material absorbing or scattering x-ray radiation, to eliminate the phenomenon of total external reflection and take the form of either a lateral surface of a truncated cone or pyramid, or cylinder, or prism.

The first two named species of the surface shape of the walls of the channels transporting the radiation of their cross-section increases uniformly in the direction from input to output, while the last two remains constant along the length of the channel. Importantly, in all these cases, the optical axis of the channels is straightforward. The implementation of the walls of the channels transporting radiation from a material absorbing or scattering x-ray radiation, or coating them inside such a material provides no reflection of radiation when it passes through the channels. As a result, the channels work on the principle of collimators and expose. In the end, each channel can be captured only radiation that has passed through the fragment of the investigated object is located exactly opposite the entrance to this channel. Therefore, the size of the field of view of the individual channel is defined by the formula (1) without the second term in the right part.

Brief description of drawings

Offer and the invention is illustrated in the drawings, showing:

in Fig.1 is a General layout of the nodes of the x-ray microscope;

in Fig.2 - perform part of the x-ray microscope lens with divergent channels of transportation of radiation with increasing towards the exit cross-section;

in Fig.3 - run part of the x-ray microscope lens with divergent channels of transportation of radiation having constant along the length of the cross section;

in Fig.4, the cross - sectional view of the lens in the case corresponding to Fig.2, when two forms of the walls of the channels transporting radiation;

in Fig.5, the cross - sectional view of the lens in the case corresponding to Fig.3, when two forms of the walls of the channels transporting radiation;

in Fig.6 - field of view of the individual channels of the lens and the trajectory of the distribution of x-ray quanta emitted by the x-ray microscope contains (Fig.1) the x-ray source 1 with an extended aperture 2, having dimensions of not less studied object 3. The latter is located in the tool (camera 4) for placing the test object. As close as possible to this tool is the input (lower) end of the 5 x-ray capillary lens 6. Near the output (larger) end of the 7 is x-ray radiation sensitive means 8 for registration. Registered this tool picture 9 density distribution of x-ray radiation passed through the object under examination 3 and transferred by the lens 6 from its input end 5 to the outlet 7, is reproduced by the monitor 10. When this occurs, the increase in the linear dimensions of the image of the object 3 is proportional to the ratio of the linear dimensions of the output 7 input 5 ends of the lens 6.

Pre-output signals of the means 8 for registration can be processed in a personal computer or a specialized computing means 11, provided with a control unit 11a. For example, the tool 11 can be fixed picture in the absence of the investigated object 3, reflecting the unevenness of the radiation intensity at the aperture 2 and the irregularity of its losses when passing through the walls of the chamber 4, the lens 6, and not the under the supervision of the investigated object this pre-recorded pattern can be used for correction of the received image with the to reflect only own the unevenness of density of the object. Thanks in the film 9 on the screen of the monitor 10 is properly rendered image 12 inhomogeneities 13 of the internal structure of the object 3.

The actual function of the lens 6 is to separate the shadow image of the object 3 on the input side of the lens 6 on the elements by the number of channels lenses and transportation each of these elements (in the form of corresponding intensity x-ray radiation passed through one or another fragment of the object 3) to the corresponding detecting element means 8 for registration. Resolution equal to the input channel diameter lenses, can be implemented, if the output signal of each channel of the lens can be fixed separately, without “mixing” of the output signals of other channels. Therefore, the above magnification must match the element size resolution (single detecting element) means 8 for registration.

Ensuring such compliance does not necessarily require the actual increase in the size of the picture element at the output of the lens 7 in comparison with the size of the input. Enough to implement by mentioning what can be done in any of the shown in Fig.2 and 3 structures of the lens.

The first of these (Fig.2) the channels 14 are filled almost the entire volume of the lens, changing its cross section along the length according to the same law as the cross-section of the lens as a whole. Channels in the design of the lens according to Fig.2 can be, in particular, a circular cone or a hexagonal pyramid. Their cross-section shown in Fig.4. This form of the most technologically advanced. The ratio of the output D input d diameter (if circular cross-sectional shape) determines the above-mentioned magnification. So that was realized a potential resolution, the dimensions of the sensitive detector elements means 8 for registration must be no more than D, and are they must be opposite to the output channel of the lens. In Fig.2 shows several of these elements 15. The same condition must be fulfilled when using the lens shown in Fig.3, in which the cross-section of the channels 16 is constantly on the length and the output diameter is equal to the inlet diameter d. Several of the detecting elements 17, satisfy this condition, also shown in Fig.3. The most technologically advanced forms channels in the design of the lens according to Fig.3 are circular cylinder and shestigrannoj prism. Their cross-Sich is I x-ray radiation (otherwise they would be considered as “channels”).

The design according to Fig.2 is energetically slightly more favorable. Sensing radiation from the same size of the fragment object, as in the construction according to Fig.3, and providing approximately the same resolution, it allows you to capture a large part of the radiation of this fragment due to the expanding nature of the channels.

In both constructions can be captured radiation only from the point of object fragments that are strictly in areas of limited continuations of the channels (see Fig.6A and 6b). With the proposed choice of the material of the walls of the channels or their material coating the radiation that is part of the channel at an angle to the wall, absorbed or dissipated and does not pass to the output. In Fig.6A and 6b, the dashed lines show the trajectory of the distribution of quanta of x-ray radiation passing to the output channel, which can only be straight. In contrast, in the known device [3], which uses the principle of total external reflection, distributed through the channels 18 may and radiation trapped in the channel inputs from the fragments of an object located outside the limits of the zones shown in Fig.6A and 6b (see Fig.6C). This can occur if the direction of propagation of radiation at the entrance to ksana in Fig.6C, at the channel output are quanta propagating both along a straight line (shown by the dashed lines), and broken (shown in solid lines) trajectories.

In the experiments performed, the image of the object was obtained with a resolution of about 1 micron when the source with linear sizes of the order of 0.1 mm, i.e., the size of the aperture of the source exceeded the permission entry about 10,000 times. There are all preconditions for obtaining a permit in future the level of 0.1 micron or better.

A significant factor in determining the prospects for practical application of the proposed microscope, is the speed of information. According to estimates, it can be in (10-100) thousands of times higher than the conventional method of projection x-ray microscopy.

These gains are achieved through the removal of restrictions on the intensity of the source used. Because it should not be microfocus and can have a finite size, high efficient intensity achievable even at low power x-ray tube.

The above examples relate to a tube with a capacity of less than 10 watts and a conical x-ray lens with the number of channels in the order of 106

Confirmed in the experiment, the indicators allow for a wide application of the proposed x-ray microscope as directly in industry, in particular, microfabrication, and in scientific research, primarily in biology and medicine.

All of the above, concerning the principles and the achieved result, equally applicable to the microscopes that use other types of radiation in the form of a stream of neutral particles, including neutrons, gamma rays, ultraviolet and infrared radiation, visible light, and radiation in the form of a stream of charged particles such as ions.

Claims

X-ray microscope that contains the extended x-ray source (1), and means (4) for placing the test object (3) and means (8) for registration and located between the x-ray capillary lens (7) having channels for transporting radiation diverging in the direction of the means (8) for registering means (4) d is ω (5) x-ray capillary lens (7), characterized in that the walls of the channels (14, 16) transportation emission x-ray capillary lens (1) is made with coated or made of a material that provides an exception to the phenomenon of total external reflection, and have the shape of a side surface or a truncated cone or pyramid, or cylinder, or prism.



 

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9 cl, 5 dwg

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