Capillary X-ray optics and polycapillary X-ray optics (Kumakhov X-ray optics) has passed a long way of development
from first assembled lenses to modern sub-micron integral
micro-lenses
Roentgen
optics evolution
1998-1999
2004-2005
Minimal
focal distance
3-5 mm
1-2 mm
Minimal
focal spot size
5-10 mkm
3-5 mkm
The Kumakhov x-ray optics, as it is world-wide known by specialists,
is based on the principle of multiple reflections from
surfaces directed to an X-ray source to achieve a maximum
capture angle. The surfaces are produced to provide the maximum
number of X-ray/neutron beam reflections when a fall angle should not
exceed some critical value.
Multiple reflections in Kumakhov x-ray optics allow turning a beam through a
significant resulting angle of the order of several degrees. This means that, when an angle is less than a critical angle,
any X-ray beam inside an empty smooth (glass) tube will be
multi-reflected from its inner surfaces creating at its end a
“virtual” X-ray source.
This also means that by directing X-ray radiation through a
special capillary system one can focus an X-ray beam into a focal
spot of different size.
This is how a Kumakhov x-ray optics and lens works and this is the principle
that became the basis for development of the first Kumakhov x-ray
optics and capillary
lens in the middle of the 80th of the 20th century.
In case of X-ray radiation for Kumakhov x-ray capillary optics, direction at the output is parallel
to a lens axis, a “half-lens” is created. It converts a beam coming
out of a point X-ray source into a quasi-parallel one.
The Kumakhov capillary x-ray half-lenses allow creating big fluxes – parallel,
horizontal and vertical – with a cross-section from several mm2
to a few tens of sm2.
The next stage in x-ray lens production development has been creation of
unique poly-capillary lenses which allowed increasing by orders the
channel number and significantly widening an operating energy range.
On the
basis of this physical principle for x-ray Kumakhov capillary optics, starting from the effect invention
about 20 years ago, the Kurchatov Institute of Atomic Power Research
laboratory (later the Institute for Roentgen Optics) developed five generations of X-ray optical
systems – lenses and half-lenses , which are:
assembled lens made of single
capillaries
monolith lens made of single
capillaries
assembled lens made of
poly-capillaries
monolith lens made of
poly-capillaries
monolith integral micro-lens
which led to first implementation of sub-micron technology
created in the IRO
A
channel diameter in X-ray capillary optics changed from 1-2 mm in the first case to sub-micron
level in the last case. The number of channels in capillary X-ray
optics increased from several
thousand to several million, moreover the first lens was as long as 1
m and patented sub-micron lenses of the last generation have the
length of about 1sm only. A focal in capillary X-ray optics spot size decreased from several mm
to several microns.
Why are this invention and its implementation as a roentgen
system so important? What advantages does the Kumakhov capillary x-ray optics provide? Where and what for is it used?
There are
several reasons that make the Kumakhov capillary x-ray optics advantageous as
compared with other X-ray methods:
A big capture angle, that is
provided by the Kumakhov X-ray capillary lens and an X-ray tube, increases
many times a capture angle of any other x-ray optics;
Possibility to create in X-ray
optics a
quasi-parallel beam, horizontal and vertical, and the beam size
can differ from several mm2 to a few tens of sm2;
Possibility to create in X-ray
optics a focused
beam of the diameter from several microns and more or to create
a “virtual” source with a linear focus.
The Kumakhov capillary x-ray optics is the most
effective x-ray optics, easily compatible with conventional X-ray tubes
having the anode of a final size.
Thus the capillary Kumakhov
x-ray optics
allows implementing ultra-bright “virtual” sources with big fluxes
using optics and conventional X-ray tubes, forming parallel or
focused X-ray tubes with the gain of the order of hundreds under low
energies as much as 1,5 keV , when the wave length is 8 A and up to
one thousand in some cases.
The
Institute for Roentgen Optics was founded on June 28, 1991 by the order # 689-p of the
Counsel of Ministers of the RSFSR on the basis of the Kurchatov
Institute of Atomic Power Research laboratory headed by professor Muradin A.Kumakhov., It was there that the idea of an X-ray
radiation control, using multiple surface reflection inside
capillaries, emerged and was realized for the first time. There they
also produced first mono-capillary roentgen/neutron lenses (the
Russian patent of professor Muradin A.Kumakhov, # 1322888, 1984). At
the same time (late 80th – early 90th of the 20th century) fields of
application for such optics were proposed.
