X-RAY WAVEGUIDE AND X-RAY WAVEGUIDE SYSTEM
An X-ray waveguide includes a core having a curved portion and a cladding. The core has a periodic structure made of different substances periodically arrayed perpendicular to a guiding direction. A critical angle for total reflection of an X-ray at a core-cladding interface is larger than a Bragg angle of the periodic structure. A critical angle for the total reflection of the X-ray at a substance interface in the periodic structure is smaller than the Bragg angle. When s is a core width in a direction perpendicular to the guiding direction and parallel to a curvature radius of the curved portion, n low is a refractive-index real part of the substance having a minimum real part of refractive index, n high is a refractive-index real part of the substance having a maximum real part of refractive index, and R is the curvature radius, [s/ln(n high /n low )]<R is satisfied.
1 . An X-ray waveguide including a core configured to guide an X-ray therethrough and a cladding configured to confine the X-ray inside the core,
wherein the core has a periodic structure in which plural substances each having a different real part of refractive index are periodically arrayed in a direction perpendicular to an interface between the core and the cladding,
a critical angle for the total reflection of the X-ray at the interface between the core and the cladding is larger than a Bragg angle attributable to the periodic structure of the core for the X-ray,
a critical angle for the total reflection at an interface between the plural substances constituting the periodic structure of the core is smaller than the Bragg angle,
the core includes a curved portion, and
a following formula is satisfied:
s
ln
(
n
high
n
low
)
<
R
where s is a width of the core in a direction perpendicular to an X-ray guiding direction and parallel to a direction in which a curvature radius is defined of the curved portion, n low is a refractive-index real part of the substance having a minimum real part of refractive index real part among the substances of the core, n high is a refractive-index real part of the substance having a maximum real part of refractive index among the substances of the core, and R is the curvature radius of the curved portion.
2 . The X-ray waveguide according to claim 1 , wherein, given that the Bragg angle is θ B (rad), a length of the waveguide at a center thereof in the curved portion is 2Rθ B .
3 . The X-ray waveguide according to claim 1 , wherein the core is a multilayer film in which the substances each having a different real part of refractive index are periodically laminated.
4 . The X-ray waveguide according to claim 1 , wherein the core is a mesostructured material.
5 . The X-ray waveguide according to claim 1 , wherein the core is made of a mesoporous material.
6 . An X-ray waveguide system including an X-ray source and an X-ray waveguide,
the X-ray source emitting an X-ray to the X-ray waveguide,
the X-ray waveguide including a core configured to guide an X-ray therethrough and a cladding configured to confine the X-ray inside the core,
wherein the core has a periodic structure in which plural substances each having a different real part of refractive index are periodically arrayed in a direction perpendicular to an interface between the core and the cladding,
a critical angle for the total reflection of the X-ray at the interface between the core and the cladding is larger than a Bragg angle attributable to the periodic structure of the core for the X-ray,
a critical angle for the total reflection at an interface between the plural substances constituting the periodic structure of the core is smaller than the Bragg angle,
the core includes a curved portion, and
a following formula is satisfied:
s
ln
(
n
high
n
low
)
<
R
where s is a width of the core in a direction perpendicular to an X-ray guiding direction and parallel to a direction in which a curvature radius is defined of the curved portion, n low is a refractive-index real part of the substance having a minimum real part of refractive index part among the substances of the core, n high is a refractive-index real part of the substance having a maximum real part of refractive index among the substances of the core, and R is the curvature radius of the curved portion.
7 . The X-ray waveguide system according to claim 6 , wherein, given that the Bragg angle is θ B (rad), a length of the waveguide at a center thereof in the curved portion is 2Rθ B .
8 . The X-ray waveguide system according to claim 6 , wherein the core is a multilayer film in which the substances each having a different real part of refractive index are periodically laminated.
9 . The X-ray waveguide system according to claim 6 , wherein the core is a mesostructured material.
10 . The X-ray waveguide system according to claim 6 , wherein the core is made of a mesoporous material.