Classifications

• • G—PHYSICS
  • G21—NUCLEAR PHYSICS; NUCLEAR ENGINEERING
  • G21K—HANDLING OF PARTICLES OR IONISING RADIATION NOT OTHERWISE PROVIDED FOR; IRRADIATION DEVICES; GAMMA RAY OR X-RAY MICROSCOPES
  • G21K1/00—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating
  • G21K1/02—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators
  • G21K1/04—Arrangements for handling particles or ionising radiation, e.g. focusing or moderating using diaphragms, collimators using variable diaphragms, shutters, choppers
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
  • G01N23/20—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
  • G01N23/20008—Constructional details of analysers, e.g. characterised by X-ray source, detector or optical system; Accessories therefor; Preparing specimens therefor
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
  • G01N23/20—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
  • G01N23/201—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials by measuring small-angle scattering
• • G—PHYSICS
  • G01—MEASURING; TESTING
  • G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
  • G01N23/00—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00
  • G01N23/20—Investigating or analysing materials by the use of wave or particle radiation, e.g. X-rays or neutrons, not covered by groups G01N3/00 – G01N17/00, G01N21/00 or G01N22/00 by using diffraction of the radiation by the materials, e.g. for investigating crystal structure; by using scattering of the radiation by the materials, e.g. for investigating non-crystalline materials; by using reflection of the radiation by the materials
  • G01N23/207—Diffractometry using detectors, e.g. using a probe in a central position and one or more displaceable detectors in circumferential positions

Definitions

• the present invention relates generally to an x-ray scattering camera, and more particularly relates to a two-dimensional x-ray scattering camera.
• the performance of the camera is typically characterized by the flux, the resolution, defined as the beam diameter at the detector position divided by the sample-to-detector distance, and a parameter
• minimum access angle i.e., the smallest angle, relative to the primary beam, at which meaningful scattering can be collected.
• a camera known as a Kratky camera using a collimation block and an x-ray source in a line projection was developed.
• the Kratky camera has achieved high resolution, good flux and Qmm, but it is a one-dimensional camera and therefore suffers from smearing. Although many de-smearing procedures have been developed, some amount of information is still unavoidably lost. Moreover, because of its one- dimensional nature, the Kratky camera can be used only for isotropic samples.
• the pinhole camera such as three-pinhole systems, were developed to overcome some of the shortcomings of the Kratky camera. The pinhole camera eliminates the lateral smearing caused by a one-dimensional beam, and can be used to investigate anisotropic samples. However, the pinhole camera has a low flux, low resolution, and its ⁇ 2 min is limited to about
• a two-dimensional x-ray scattering camera includes a source, an optic, a detector, and a pair of collimating blocks.
• the source emits x-ray beams that are reflected by the optic towards a sample.
• the detector detects scattering from the sample, the pair of collimating blocks is positioned between the optic and the detector to collimate the beam.
• the bottom surface of one block is substantially parallel to the top surface of the other block, and the blocks are ratable relative to the beam about a pivot.
• a particular feature of this system is that the beam intensity distribution at the detector position is independent of the block collimation, which by nature is asymmetric.
• Such a beam can be formed by using a two- dimensional multilayer optic ( ⁇ CMF) and a microfocusing source. The combination of these two elements (block collimation and the highly defined
• the camera can be used to investigate anisotropic material and can be configured into a high resolution reflectometer, or a high resolution reflective SAXS camera. Since the sample-to-detector distance is not necessarily as long as in the pinhole camera case, the camera has a large angular range and may make it possible to use the camera in wide angle scattering.
• FIG. 1 is a schematic illustration of a Kratky camera ;
• FIG. 2 is a schematic illustration of a camera with a two- dimensional x-ray source in accordance with the invention;
• FIG. 3 is a schematic illustration of the collimation blocks rotated about a pivot to adjust the camera's resolution and Q m j n ;
• FIG. 4 is a perspective view of a portion of the camera shown in FIGs. 2 and 3; and
• FIG. 5 is an alternative embodiment of a camera with a two- dimensional x-ray source in accordance with the invention.
• FIG. 1 depicts a Kratky camera 10 commonly used for small angle x-ray scattering.
• the camera 10 includes a detector 12 and an x-ray source 14.
• the x-ray source 14 is a one dimensional line source.
• X-rays are collimated by a pair of blocks 16 and 18 aligned in a common plane (i.e. the plane of the paper).
• the collimation blocks direct x-rays 19 at a sample (S), the scattering of which is captured by the detector 12.
• S sample
• a Ni filter can be employed to suppress K ⁇ radiation and soft
• the Kratky camera 10 has good flux and Q mia but the one-
• the Kratky camera 10 makes it suitable for use with only isotropic samples. Moreover, the Kratky camera produces a scattered x-ray pattern that suffers from severe distortion know as smearing. Although many de-smearing routines have been proposed and implemented, some information is unavoidably lost, and therefore, the resolution, in particular, ⁇ d/d, where ⁇ d is the smallest resolvable d-spacing at the specific d, is compromised .
• Kratky cameras have employed focusing multilayer optics that enhances the performance of the camera.
• the flux can be increased by a factor of about forty with the use of multilayer optics.
• the background noise caused by K ⁇ and Bremsstrahlung radiation is removed, and the resolution, which can be measured by the beam width at the detector ( ⁇ B) divided by the distance between the sample and the detector (SD), is improved because of the enhanced focusing capabilities of the optics. Nonetheless, the one-dimensional nature and the smearing problems associated with the Kratky camera remain.
• a two-dimensional camera 20 includes a pair of collimating blocks 22 and 24, a microfocusing source 30 and an optic 32, such as a two-dimensional multi-layer optic (or ⁇ CMF optic) in accordance with the invention.
• the optic 32 can be of the type described in U.S. Patent No. 6,041 ,099 or U.S. Patent No. 6,014,423, the entire contents of which are incorporated herein by reference.
• the combination of the microfocusing source 30 and the optic 32 produces a well defined two- dimensional beam 36.
• blocks 22 and 24 provides a camera with high resolution and low ⁇ min .
• camera 20 has exceptional resolution (i.e. good ⁇ d/d) and angular range
• the Q min -range can be easily and continuously changed by rotating the collimating blocks 22 and 24 about, for example, a pivot 38, and moving a beam stop 34 positioned below a detector 40 (FIG. 4) away and towards the detector.
• the rotation of the collimating blocks 22 and 24 can be about another position, such as edge 39 of the block 24.
• the beam stop 34 and detector 40 do not have to rotate with the collimating blocks 22 and 24. Because of the small angular variations, the position of the detector 40 can be fixed without any repositioning, and the position of the beam stop 34 is adjusted to block parasitic scattering or to allow access to a smaller angular zone.
• the collimating blocks 22 and 24 offer a parasitic-scattering-free zone above the a-b line identified in FIGs. 2 and 3. Since the beam 36 is well defined and symmetric about the primary beam direction, the scattering pattern is two-dimensional in nature. The beam is symmetric because the deviation of the beam from being focused is determined by the source intensity distribution, which can be considered as symmetric about the primary beam axis. If the beam 36 is a focusing beam and the detector 40 is at the focal point of the optic 40, a high resolution (i.e., small ⁇ B/SD) can be achieved.
• the beam shape at the location of the detector 40 is not affected by the position of the collimating blocks 22 and 24. In other words, the beam shape at the detector 40 does not depend on the setting of a
• the beam 36 at the location of the sample S can be sliced into
• the sample S can be mounted to a stage integrated with the camera 20 so that the stage rotates the sample S about the longitudinal axis of the primary beam 36, enabling the investigator to obtain a complete scattering pattern.
• the flux of the camera 20 is at least a few times higher, and hence the total integration time is lower, than that of a pinhole camera.
• the g min can be easily adjusted by rocking
• the collimating system of blocks 22 and 24 about the pivot 38 at the center of the collimating system.
• the rotational center can also be at a corner of one of the collimating blocks.
• the beam stopper 34 can also be adjusted by moving it relative to the detector
• the Q m - n can easily reach about 0.0003 A '1 , equivalent to a
• the pinhole camera can achieve a d ma ⁇ of about 1000 with an acceptable flux, which is a distinct disadvantaged compared to the camera 20.
• the flux of the camera 20 does not decrease as 1/r 2 , where r is the distance between the source and detector. Therefore, the effective length of the camera 20 can be longer than that of the
• the camera system 20 is very flexible and easy to use.
• a small detector can be positioned in front of the beam stop 34 (the sample side) to measure the intensity of the primary beam and the absorption of the sample.
• the angular range can be extended easily for wide angle scattering.
• ⁇ d/d is proportional to ⁇ B/SD, and the small size of a microfocusing source offers superior resolution.
• the spot size of the microfocusing source such as a Bede Scientific's MicroSourceTM, a company in the United Kingdom, can be adjusted to improve the resolution further.
• the camera 20 is quite appropriate for use in medical small angle x- ray scattering, allowing the observation of first order peaks around 900 A. With parallel beam optics, the camera 20 is quite suitable for use as a reflectometer. The camera 20 can be used in reflective small angle x-ray scattering in surface analysis, such as performed, for example, in semiconductor metrology.
• the blocks 22 and 24 may be integrated as a single unit.
• an implementation of a two-dimensional camera 50 shown in FIG. 5 includes a U-shaped structure 52 with a top portion that functions as one of the collimating blocks 24.
• the other collimating block 22 is mounted to the top of the legs 54 of the structure 52 so that the two blocks 22 and 24 are naturally aligned.
• the block 22 can be a portion of a U-shaped structure, and the block 24 is mounted to it.
• the beam can be conditioned by forming a two-dimensional beam, enhancing flux and decreasing divergence by collimating or focusing the beam, or monochromatizing the beam to improve its spectrum, or any combination of the foregoing.

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• Analysing Materials By The Use Of Radiation (AREA)

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• 2005
  • 2005-05-31 US US11/142,862 patent/US7139366B1/en not_active Expired - Lifetime
• 2006
  • 2006-01-04 EP EP06717483.9A patent/EP1886125B1/en not_active Expired - Lifetime
  • 2006-01-04 WO PCT/US2006/000290 patent/WO2006130182A1/en not_active Ceased
  • 2006-01-04 CA CA2610555A patent/CA2610555C/en not_active Expired - Lifetime
  • 2006-01-04 JP JP2008514618A patent/JP5214442B2/ja not_active Expired - Lifetime
• 2007
  • 2007-11-30 US US11/948,304 patent/US7734011B2/en not_active Expired - Lifetime
• 2010
  • 2010-04-05 US US12/753,989 patent/US8094780B2/en not_active Expired - Lifetime

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