nL;

Figure 8
Electron micrograph of a portion of the
atrface of a glass collimatoL based on
the so-called microchannel plate. The
main use of the miuochannel plate in
X-ray astronomy is to amplify the
image. The system of empty gJass
capillaries can aTso be used to focus X
ruys (the Kumakhov lens).
role of the diffraction-induced blurring
is not as significant (for the
range of sizes used in the experiment)because
the wavelength of an
X-ray photon is far less than that of
a photon of visible radiation.
It's also interesting to determine
how the optical characteristics of a
polyporoid layer depend on the parameters
of the pore-tubes-that is,
on the diameter D andlength I. The
optical properties of any collimator (a
polyporoid layer included) are characterrzed
first of all by the dependence
of the transmittance 7 on the angle u
between the collimator axis and the
direction of a parallel beam. You may
be tempted to try a third experiment
(1)
t-
r(a)= q2!999 |
,r.rin
TEL
.DD
where - arctan- ( 61 < arctarr-
LL
l2l 7(u)= 4
where 0
Figure 9
Ir4;Y
\l t'o )
-D
L
?[,...o, o -1g i r-f " I l''.l,
;1""'""t e['I'el,J]'
llSV HlS, Sl{ 3, &r.r*
P olymer porous collimator.
to measure the function flo), but try
to find it theoretically instead. This
task will be of particular interest to
math aficionados. Here I'11 merely
give the result: see equation (1) in
the box below, where 7, is the maximum
transmittance of the collimator
(at cr : 0). When the angular view
of the collimator is small-that is,
u