<<
i‐FCX
>>
“Fast
Contrast
X‐ray
Imaging”
Gr.
V
LNF
INFN
in
collabora3on
with
INFN
Pisa
//
INFN
Ferrara
//
IM
CNR
Napoli
The
main
aim
is
to
develop
a
new
imaging
technique
on
the
base
of
polycapillary
op3cs
in
order
to
study
low
contrast
and
fast
developing
processes
Dura3on:
2010‐2012:
3
year (2+1)
Par3cipants:
LNF: Ferrara
INFN: Napoli
CNR: Collabora3on:
Pisa
INFN:
S.
Dabagov
S.B.
Dabagov
(Resp.)
D.
Hampai G.
Cappuccio
A.
Esposito A.
Gorghinian SPARC M.
Gambaccini A.
Taibi L.
Allocca
(Ass) L.
MarchiZo
(Ass)
S.
Alfuso
(Ass) 40%
50%
40%
10%
30%
>>>
50%
50%
30%
50%
50%
U.
Bo\gli
(Resp.
Project
BEATS)
P.
Delogu
M.
Endrizzi
i‐FCX
2
Scien3fic
Program:
The
main
aim
is
developing
a
new
imaging
technique
on
the
base
of
polycapillary
op3cs
in
order
to
study
low
contrast
and
fast
developing
processes,
namely
to
study:
•  the
kine3cs
of
fast
spray
injec3on,
the
fuel
sizes
and
their
spa3al
and
temporal
distribu3ons;
that
is
fundamental
both
for
the
injec3on
apparatus
design
and
database
for
the
calibra3on
of
provisional
numerical
codes:
–  design
of
specially
dedicated
experimental
facility;
–  image
developing
studies;
–  simula3ons
on
imaging
techniques;
developing
special
computer
codes.
•  new
op3cal
schemes
to
be
used
in
the
beams
of
Thomson
source
for
ge\ng
high
contrast
resolu3on;
studies
on
contrast
imaging
by
means
of
polycapillary
op3cal
systems:
–  calcula3ons/simula3ons
and
op3cal
scheme
design;
–  experimental
studies
on
various
polycapillary
op3cal
configura3ons;
–  design
of
dedicated
test
facility.
•  various
aspects
for
radiography
applica3ons
of
polycapillary
op3cs
in
medicine
and
biology:
–  simula3ons
of
the
use
of
polycapillary
op3cs
in
combina3on
with
compact
x‐ray
sources
based
on
electron
accelerators
to
improve
contrast
resolu3on
without
increase
of
irradia3on
dose;
–  test
of
imaging
technique
by
means
of
typical
samples
for
medical
and
biological
applica3ons.
S.
Dabagov
i‐FCX
3
Budget:
2010:
2011:
@
@
@
@
@
@
@
@
@
@
@
@
157,1
k€
90,5
k€ Total
2
years: 247,6
k€ 2012:
???
Tubo per raggi X al Cr completo di cuffia e alimentatore HV;
Parti ottiche
Software per imaging (grabber)
Pellicole per raggi X
Generatore di segnali e ritardi
Trasduttore di pressione piezoquarzo con centralina amplificatore
Pompa pneumatica con filtri, raccorderia e centralina di gestione
Motore asincrono trifase da 10 CV con regolatore di velocità
CCD detector per raggi X
Parti elettromeccaniche per movimentazione remota di ottiche
Chopper per sincronizzazione
Lock-in amplifier
@ Cabinet schermato per raggi X con tavolo ottico e cappa aspirante
@ Camera sferica per apparato di inezione
S.
Dabagov
i‐FCX
4
Basic idea of polycapillary optics is very
close to the phenomenon of charged
particle channeling
@ beam bending through large angles
@ divergent beam to convergent one
@ divergent to quasiparallel & vv
Number of applications
@ scientific instrumentation (XRF, XRD)
@ elemental/structural analysis
@ medicine (diagnostics, therapy)
@ astrophysics
S.
Dabagov
i‐FCX
5
1st generation:
[m]
2d generation:
[cm]
5th generation:
[µm]
S.
Dabagov
3d & 4th generations:
[mm]
?n-capillaries?
i‐FCX
6
Genera5on • 
• 
• 
• 
• 
1st
2nd
3rd
4th
5th
S.
Dabagov
Kind
of
op5cs
Sizes:
length
&
channel
&
energy
Assembled
lens
made
of
single
capillaries 1
m
&
1
mm
&
≤
10
keV
Monolithic
lens
made
of
single
capillaries 10‐30
cm
&
0.1‐1
mm
&
≤
10
keV Assembled
lens
made
of
polycapillaries
10
cm
&
10‐50
µm
&
≤
20
keV
Monolihic
lens
made
of
polycapillaries
4‐10
cm
&
1‐10
µm
&
≤
50
keV
Monolithic
integral
micro
lens
1‐3
cm
&
0.3‐1
µm
&
≤
100
keV
i‐FCX
7
S.
Dabagov
i‐FCX
8
X-ray Cu Source
Power=50 Watt
Intensity=1mA
Voltage=50kV
Quasi-Parallel Beam
Sample
Image on CCD
Polycapillary Semi-Lens
ΔX − ΔX 0 ∝ l ⋅ Δθ
l – “sample-detector” distance;
Δθ - residual divergence behind
the optics
€
S.
Dabagov
i‐FCX
9
z (cm)
z (cm)
x (pixel)
S.
Dabagov
i‐FCX
x (pixel)
10
•  Hole
Width
37µm
•  Bar
Width
25µm
S.
Dabagov
23 cm Polycapillary – CCD
Detector
polycapillary pillar
i‐FCX
11
•  Hole
Width
19µm
•  Bar
Width
6µm
23 cm optics – CCD
S.
Dabagov
i‐FCX
44 cm optics – CCD
12
ωi
ω1
ω2
ω3
g-lens
sample / ”3CCD” x-detector
S.
Dabagov
i‐FCX
13
<< i >>
kinetics of fast spray injection
the fuel sizes and their spatial and
temporal distributions
LNF + CNR Napoli
S.
Dabagov
i‐FCX
14
S.
Dabagov
i‐FCX
15
S.
Dabagov
i‐FCX
16
Cu Kα X-ray source (50 kV, 1 mA, spot 45x45 µm2) in combination with a half polycapillary lens
(focal distance of ~ 91 mm, transmission ̴ 60%, divergence ̴ 1.4 mrad)
Photonic Science CCD (working area 14.4x10.7 mm2, resolution 10.4x10.4 µm2).
The repetition rate of the injection - 3 Hz (spray duration 35 ms)
Low absorption ~ 1-2% !
S.
Dabagov
i‐FCX
17
<< ii >>
new optical schemes to be used in the
beams of Thomson source
for getting high contrast resolution
LNF + INFN Pisa
S.
Dabagov
i‐FCX
18
S.
Dabagov
i‐FCX
19
not optimized
S.
Dabagov
i‐FCX
20
<< iii >>
various aspects for radiography
applications of polycapillary optics
in medicine and biology
LNF + INFN Ferrara
S.
Dabagov
i‐FCX
21
MIRRORCLE source: 6-20 MeV e-
S.
Dabagov
i‐FCX
22
1)  Radiotherapy:
-  to study the possibility to get a high flux X radiation from
conventional X-ray tubes (Mo or higher, the best K-edge of
iodine) and successfully to focus it on a tumor;
2) Radiodiagnostics:
-  to use polycapillary systems in order to cut higher tail of X
radiation behind a thin crystal irradiated by MeV electrons from
compact electron accelerators (Mirrorcle).
S.
Dabagov
i‐FCX
23
S.
Dabagov
i‐FCX
24
@ basic
criteria for revealing “a wave”
L
λ
plasmon energy
Curved surface (capillary):
@ planar µ-guide
Taking
into
account
that
a
skin
layer
where
the
reflec@on
is
formed,
is
negligible
thin
in
respect
with
the
guide
wall
thickness
d
Maximum number of the waveguide modes for the
fixed wave number k in respect with geometrical
parameters of the waveguide
single mode propagation
@ down to bulk X-ray channeling
θ << 1 (θ c ~ 10−3 )
λ →
λ⊥ >> λ
d0 ~ 1µm ÷10µm :
λ⊥ << d0
€
θd = λ d0 ~ θc
λ⊥ d 0 ~ 1
@ wave field formation in a planar waveguide
Diffraction from Si corner (gap 30 nm; λ=0.1 nm):
(a) analytical solution;
(b) computer simulation
@ planar n-guide
:: quantum states of channeling
:: character of radiation transmission ::
:: the ray optics approach for describing
radiation propagation
ζ
=
2πθсa/λ
=
2πa/λ┴c
[λ┴c
=
λ/θc
]
::
the
number
of
bound
modes
N.
ζ
>>
2π
N
>>1
::
the
geometric
op@cs
approxima@on
ζ
>>
2π
a
>>
λ┴c
[glass
λ┴c
=
40
nm]
Thus
for
a
wide
waveguide
a
>>
40
nm
there
are
many
bound
modes
and
mul@ple
reflec@on
of
rays
can
be
used.
•  In
the
other
limit
ζ
<<
1
or
a
<<
7nm
one
even
bound
mode
• 
• 
• 
@ planar n-guide
Ψin ( x ) = ∑ Qm Ψm ( x ),
Expansion in a set of guiding modes ::
m
d
Qm =
∫e
ik⊥in x
Ψm ( x ) dx
:: population of m-th mode
−d
€
€
•  For an ultra narrow waveguide with aperture ::
2a = 5.2 nm (ζ = 1/sqrt(6))
the integral intensity of the bound mode ::
P = Q12 = 25a k┴in=0
Normal incidence of the incoming beam ::
Effective aperture:: about one order larger than the geometrical one
• 
Strong dependence on the incidence angle:
Q12 = 4.5a at θin = k┴in/k = 0.5•θc
Q12 = 0.6a at θin = θc.
@ planar n-guide
Angular dependence for
the population of a single
mode propagation in ultra
narrow planar waveguide.
The dependence is normalized to geometrical acceptance of the waveguide.
•  Integral
within
1 sin(2ϕ m ) 
P = P(0) +

2
4
ϕ


m
-θm ≤ θin ≤ θm
ϕ m = arctan
θm 6
θc
€
•  For
the
considered
ultra
narrow
waveguide
the
intensity
at
the
gap
center
€
I
=
3.5
I0
at
θin
=
0
‐
flux
peaking
effect
•  ASenua@on
with
penetra@on
due
to
absorp@on!
In
the
glass
cladding
73
%
of
the
wave
intensity
(tunneling
length
~3a
≈
8
nm)
…
the
strong
tunneling
effect…
Normalized value of radiation power integrated within vacuum gap vs. coordinate x
calculated for step-like entrance function (bottom lines) and for total calculated field
(top lines). Solid lines are the result of computer simulation and dashed lines are
the result of asymptotic solution
@ circular n-guide
wave equation in circular guide
J_{m}(y) and K_{m}(y) –
the 1st kind and the modified 2nd
kind Bessel functions
Two limits:
inside
the core
the cladding
dispersion equation
@ circular n-guide
@ effective aperture is larger than the geometric one in ~1010 times;
due to very large tunneling length, which is equal to
no absorption!
@ the average effective aperture at θm=θc only 24 times is larger than the geometric
one.
@ the flux peaking is also strong – the intensity of the bound mode at the center of
wave guide at θin = 0 is equal I(0) = Q012•A2 = 576.
Intensity increase is 576 times due to the logarithmic singularity of the function
K0(x)|
Flux peaking effect for a
circular guide.
Due to the flux peaking
effect, at the guide
center, the radiation
intensity may overcome
in 2 orders the intensity
of the incoming beam
@ nanocapillaries
- number of modes
~ 40 nm for glass
Tunneling length
~ 8 nm
@ X-channeling
Analysis
of
radia@on
propaga@on
through
the
guides
of
various
shapes,
above
presented,
has
shown
that
all
the
observed
features
can
be
described
within
unified
theory
of
X‐ray
channeling:
‐
surface
channeling
in
μ‐size
guides
‐
bulk
channeling
in
n‐size
guides.
The
main
criterion
defining
character
of
radia@on
propaga@on
is
the
ra@o
between
the
transverse
wavelength
of
radia@on
and
the
effec@ve
size
of
a
guide,
i.e.
‐
the
ra5o
between
the
diffrac5on
and
Fresnel
angles.
@
this
ra@o
is
rather
small,
i.e.
when
the
number
of
bound
states
is
large,
the
ray
op5cs
approxima@on
‐
λ⊥
≃
d,
a
few
modes
will
be
formed
in
a
quantum
well;
‐
λ⊥
≫
d
‐
just
a
single
mode
.
@
flux
peaking
of
X
radia5on,
i.e.
the
increase
of
the
channeling
state
intensity
at
the
center
of
a
guide
‐
a
proper
channeling
effect
that
can
be
explained
only
by
the
modal
regime
of
radia@on
propaga@on,
and
may
find
an
interes@ng
applica@on
for
the
purposes
of
extreme
focusing.
@
all
the
considera@ons
taken
for
X‐rays
should
be
valid
for
thermal
neutrons.