CN2590044Y - Recording device of high magnifying ratio X-ray photoelectron coaxial hologram - Google Patents

Abstract

The utility model relates to a recording device of a high magnifying ratio X-ray photoelectron coaxial hologram, which comprises an X-ray source in a vacuum cavity. X-rays transmitted by the X-ray source are diffracted and focused by a zone plate and are filtered by a pinhole diaphragm; quasi monochromatic X-rays penetrating through a sample to be measured are interfered by object beams scattered by non-transparent and translucent parts in the sample to be measured and reference beams penetrating through a transparent part in the sample to be measured in an overlapping way. The X-ray hologram is converted to photoelectron interference field through a photocathode, and is output to the receiving surface of a receiver connected to a computer through being accelerated by an accelerating anode and amplified and imaged through an amplifying electromagnetic lens; the information enters the computer to be carried out data processing and image reconstruction. The utility model has high resolution which can reach 0.5 nm. The utility model is convenient to operate, and can be used for rapidly observing a three-dimensional ultrastructure of a biological sample under natural state in real time.

Description

The pen recorder of high enlargement ratio x-ray photoelectron in-line hologram

Technical field:

The utility model is the device that writes down the x-ray photoelectron in-line hologram of high enlargement ratio about a kind of, particularly relates to a kind of record of hologram of photocathode photoelectron amplification.

Background technology:

In recent years, because the synchrotron radiation source fast development, and the appearance of high brightness x-ray laser, the development of X ray holography promoted greatly.Formerly in the technology, the device of record X ray hologram has two kinds:

1. (referring to technology [] formerly J.0pt.Soc.Am. (A), 1990,7 (10): 1847-1861), Fig. 1 is for covering the coaxial X ray hologram recorder of cypress structural representation for lid cypress coaxial X ray hologram recording apparatus.Polychrome synchrotron radiation X-ray source 1 is after the monochromator filtering of convergent wave strap 2 and pinhole diaphragm 3 compositions, obtain quasi monochromatic X ray, wherein a part be used to provide to testing sample 4 illumination as the thing bundle, be used for reference to bundle without another part of testing sample 4 disturbances.The thing bundle is restrainted on same axis with reference, so claim coaxial X ray holography.Polymethylmethacrylate (PMMA) 5 with photoresist is as the recording medium recording hologram, then, with high-resolution transmission electron microscope or atomic force microscope, hologram is read amplification, carry out digitizing with microdensitometer again, be input to computing machine and carry out digital reconstruction.The best result that this recording mode obtains, resolution reach 40nm (referring to technology []: M.Hwells formerly, C.Jacobsen, et al., Science, 238,1987,514).

2. do not have lens Fourier transform X ray hologram recording apparatus (referring to technology []: Science formerly, 1992,256:1009-1012).By the relevant X-ray beam of x-ray source 1 outgoing, after convergent wave strap 2, its zero order wave testing sample 4 that is used for throwing light on, its first-order diffraction ripple focuses on and produces with reference to point source, testing sample 4 with reference to point source at grade.On this plane, place a pinhole diaphragm 3, rise and cut apart filter action.Thing light and reference light meet in the zone behind the certain distance of diaphragm back, overlap to produce interference fringe, are scribbled charge-coupled device (CCD) 7 records of XRF powder.The data of record are directly imported computing machine and are carried out digital reconstruction after the A/D conversion.Before CCD, place a diaphragm 6, stop the direct irradiation of zero order light to CCD7.

The shortcoming that above-mentioned two kinds of hologram recording apparatus mainly exist is:

1. cover the coaxial X ray hologram recording apparatus of cypress, though the light path that adopts is simple, light requirement is learned element, also need not meticulous adjustment light path, and it is very high to the resolution requirement of recording medium.Because obtain higher holographic imaging resolution, then recording medium need write down senior time very meticulous interference fringe.And if improve the resolution of photoresist, then its sensitivity meeting descends, and this just needs to increase exposure, and the increase of time shutter very easily causes recording medium to be damaged by electron beam.In addition, because it is too little to be recorded in the spacing of the holographic interference fringes on the photoresist, need through high-resolution follow-up equipment, the amplification of reading as transmission electron microscope or atomic force microscope, transcribe on film, with microdensitometer the image on the film is carried out digitizing again, be converted to data file, just can be input to computing machine and carry out digital reconstruction, hologram is through repeatedly processing like this, amplify, developing and printing, processes such as digitized processing, introduced very big noise, reduced signal to noise ratio (S/N ratio) and image quality, therefore covering the coaxial X ray holographic apparatus of cypress is difficult to obtain nearly diffraction limit high resolving power.

2. above-mentioned second kind of no lens Fourier transform X ray holographic microscope that device is used, though lower to the resolution requirement of recording medium, require very high to the fresnel's zone plate that produces with reference to point source.Because the spatial frequency of the peripheral endless belt of fresnel's zone plate is with the resolution of decision X ray lensless Fourier transform hologram.And the making of high-resolution fresnel's zone plate faces the problem of high-resolution recording medium equally, so the making of this holographic microscope is difficult to realize equally.

Summary of the invention:

The utility model proposes a kind of new pen recorder at existing shortcoming in the above-mentioned technology formerly, and promptly high enlargement ratio x-ray photoelectron amplifies the pen recorder of in-line hologram.Be with the X ray hologram, by an X ray photocathode, be translated into photoelectronic hologram, utilize the acceleration amplifier section of electron microscope again, coherent light electronics to photocathode amplifies, and receives with CCD then, notes the electronic holographic interferogram of amplification, import computing machine again and be reconstructed, just obtain the micro-intensified image of object.

High enlargement ratio x-ray photoelectron in-line hologram pen recorder of the present utility model as shown in Figure 3.

Be equipped with x-ray source 1 for 13 li at vacuum chamber, locate to be equipped with a zone plate 2 at the 10000mm of distance x-ray source 1 (10m), first-order diffraction focus 0 place at zone plate 2, put a pinhole diaphragm 3, put a photocathode 8 at distance pinhole diaphragm 3 for the 700mm place, between pinhole diaphragm 3 and photocathode 8, apart from photocathode 8 is that 50 μ m are put testing sample 4 to the 1mm disposal, between photocathode 8 and receiver 11, from photocathode 8, be equipped with accelerating anode 9 successively and amplify electromagnetic lens 10, the output of receiver 11 links to each other with computing machine 12.

Said zone plate 2 is to be used for heterogeneous X-ray is carried out chromatic dispersion, and it and pinhole diaphragm 3 formed a monochromator, becomes homogeneous X-ray surely from the X ray of pinhole diaphragm 3 outgoing, incides on the testing sample 4.It is to be noted especially: testing sample 4 is a very important parameter to the distance of photocathode, and it directly has influence on imaging resolution and to electron beam source coherence's requirement, available following formulate: $\frac{{\mathrm{\λ}}^2}{\mathrm{\Δ\λ}}=\frac{0.186\mathrm{\λz}}{r_0^2}$

In the formula, λ is the X ray wavelength, and Δ λ is the live width of X ray, r ₀Be the minimum dimension that can differentiate in the testing sample 4, become the radius of matter-element, Z is the distance of testing sample 4 to photocathode 9, and general desirable 50 μ m are to 1mm.

Said photocathode 8, be that the X ray that will be radiated at above it is converted to photoelectron, the material of photocathode 8 has three classes usually: (1) metal species, mainly contain gold, copper, magnesium, tantalum etc., its characteristic is that threshold power height, quantum efficiency are low, because most of incident optical energy converts heat energy to, the photocathode that high-repetition-rate is turned round needs cooling; Advantage is easy preparation, and long service life is low to the vacuum tightness requirement, is generally 10 ^-5～10 ^-8(2) metallic compound and alloy typically have LaB ₆, higher quantum efficiency is arranged, ultraviolet band there is higher sensitivity, require also low to vacuum tightness.(3) semiconductor photocathode.Mainly be the polybase antimonide material, as: Cs ₃Sb, CsK ₂Sb and GaAs etc.The quantum efficiency of semiconductor photocathode is the highest, can reach 2～8%; The threshold value merit is lower, can obtain higher current density.Unique shortcoming is that the life-span is short, has only tens hours.(referring to document: Chen Jianwen, Ou Yangbin, the king Zhijiang River, light laser technical progress,, the 3rd volume, 1～5 in 1992).

In actual the use, must from three class materials, make one's options according to the combination property of each side such as the threshold value merit of the wavelength of x-ray photon, required photocathode and quantum efficiency.Select the metal of long service life to make photocathode in the utility model.

X ray hologram recorder of the present utility model:

The X ray that sends from x-ray source 1, focus on and pinhole diaphragm 3 filtering through zone plate 2 chromatic dispersion diffraction, become homogeneous X-ray surely, incide on the testing sample 4, the accurate homogeneous X-ray of the scattering of and translucent portion opaque to X ray is as the thing bundle in the testing sample 4; Another part accurate homogeneous X-ray of transparent part in testing sample 4 is with reference to bundle; Thing bundle and the overlapping interference of reference bundle form an interference field that covers the coaxial X ray holography of cypress.When this interference field affacts on the photocathode 9, just produce corresponding photoelectron interference field.After carrying out photoelectron conversion by photocathode, carried the photoelectron of testing sample 4 information, quicken through accelerating anode 9 again and electromagnetic lens 10 amplification imagings on the receiving plane of receiver 11.In the utility model, receiver 11 adopts charge-coupled device (CCD), and the output of receiver 11 is input to carries out data processing, reproduced image in the computing machine 12.The enlargement factor of amplifying electromagnetic lens 10 depends on the enlargement factor of electron microscope, can be from several thousand times to 1,000,000 times.So just greatly reduce requirement to the CCD resolution of receiver 11.

The major advantage that the utility model is compared with technology formerly is: 1. owing to adopt photocathode 8 to replace formerly in the technology [], and the PMMA recording medium in the lid cypress in-line holographic device, the resolution of system imaging improves greatly, can reach about 0.5nm.2. adopt to amplify electromagnetic lens 10 in the utility model and directly amplifies, avoided formerly technology [] to cover in the cypress in-line holographic device, to the processing procedure of repeatedly processing, amplify, processing of hologram, more convenient operation, the noise of introducing is littler.3.CCD the signal that detects outputs to computing machine when carrying out digital reconstruction, can handle reproducing the result, eliminates " twin image " interference noise in the in-line holographic, can realize " real-time monitored " to biological sample to be measured.

Description of drawings:

Fig. 1 is in the technology [] formerly, the structure light path synoptic diagram of the coaxial X ray holographic apparatus of lid cypress.

Fig. 2 is in the technology [] formerly, the structure light path synoptic diagram of no lens Fourier transform X ray holographic apparatus.

Fig. 3 is the recording device structure synoptic diagram of high enlargement ratio x-ray photoelectron in-line hologram of the present utility model.

Embodiment:

As above-mentioned high enlargement ratio x-ray photoelectron in-line holographic device of the present utility model structure shown in Figure 3, the X ray that sends from the synchrotron radiation source as x-ray source 1 is by the chromatic dispersion and pinhole diaphragm 3 filtering of zone plate 2.According to the character that the focal length and the wavelength of zone plate 2 is inversely proportional to, the X ray chromatic dispersion of different wave length can be carried out filtering with pinhole diaphragm 3 again, and is reduced light line degree, adjust the size of pinhole diaphragm 3, can obtain the accurate homogeneous X-ray bundle of required spatial coherence.The centre wavelength of zone plate 2 is 2.3nm, outermost ring width 0.465 μ m, and number of rings N=1506, the radius p=1.4mm of zone plate 2, one-level focal length are 566mm.Zone plate 2 is elected 10m as with the distance of x-ray source 1, the aperture d=8 μ m of pinhole diaphragm 3, and live width Δ λ=λ d/p=0.013nm then, monochromaticity is λ/Δ λ=10 ³, temporal coherent length is L _c=λ ²/ Δ λ=0.407 μ m.Testing sample 4 is R=700mm apart from pinhole diaphragm 3, and then the coherent ranges at this place is b=R λ/d=201 μ m.This shows to have certain coherence, be fit to carry out holographic imaging through the X ray after the monochromatization.

After the accurate homogeneous X-ray bundle irradiation testing sample 4, form the coaxial X ray holographic interference of a lid cypress field.The X ray field irradiation of this interference produces photoelectron holographic interference field on photocathode 8.Photocathode 9 is to be made of metal tantalum, and testing sample 4 is cancer cell sections of small white mouse.Testing sample 4 is 500 μ m apart from photocathode 8 apart from Z.The structural information that contains testing sample 4 by the photoelectron of photocathode 8 ejaculations, be accelerated anode 9 acceleration and amplification electromagnetic lens 10 and carry out amplification imaging, so, on the receiver 11 of CCD, form a photoelectron holographic interference pattern that contains testing sample 4 structural informations.

Because the interference fringe spacing can be amplified by amplifying electromagnetic lens 10, therefore greatly reduces the requirement to receiver 11 resolution.Adopt receiver 11 records of CCD and, can directly reappear the structural images of acquisition testing sample 4 at computing machine 13 enterprising line number words through the A/D conversion.

Photocathode photoelectron amplifying X-ray holographic apparatus of the present utility model, can realize observing in real time, apace the three-dimensional hyperfine structure of the biological sample under the state of nature, resolution can reach diffraction limit, be applied in the observational study of modern medical service diagnosis and biologically active cell, have accuracy, authenticity and promptness.

Claims (1)

1. the pen recorder of the x-ray photoelectron in-line hologram of a high enlargement ratio, comprise: be seated in the x-ray source (1) in the vacuum chamber (13), in vacuum chamber (13), the 10m place is equipped with zone plate (2) apart from x-ray source (1), first-order diffraction focus (0) at zone plate (2) is located, be equipped with a pinhole diaphragm (3), have output to be connected on the outer computing machine (12) of vacuum chamber (13).It is characterized in that being equipped with photocathode (8) apart from pinhole diaphragm (3) 700mm place in the vacuum chamber (13); Testing sample (4) is seated between pinhole diaphragm (3) and the photocathode (8), apart from photocathode (8) 50 μ m to the 1mm place; Between photocathode (8) and receiver (11), be equipped with and amplify electromagnetic lens (10).

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