Is Narmada water being made to flow in Sabarmati not supplied to city of Ahmedabad? This has furthered the idea of river...
I have been selling glass for commercial buildings talking about light, thermal/solar heat gain etc.etc..but I...
Dear Saxena ji,
Thank you for inquiry.
West facing windows can be a big source of heat, first measure which you...
PARTICLE accelerators are among the
most sophisticated machines built by
humankind. The precision which drives
these machines, the magnitude of the
accelerator facilities and the sophisticated electronics which are the machines'
hallmark, are usually the results of a
collaboration of many people. The
technology also has many spin-offs in
areas like material science and medical
x-ray sources, used extensively by
material scientists, are a direct result of
advances in accelerator technology.
Currently, the x-ray sources which are
in operation the world over use electron
storage rings. These are, basically, accelerators -which speed up beams of electrons to high energies and
force them into a circular
path using very powerful
magnets. This current generation of x-ray sources
accelerates electrons to
about eight billion electron
volts, passing them
through devices called
'wiggleers' and 'undulators', where they produce
thin beams of x-rays.
These pulses are then
used to study materials or
carry out other experiments requiring x-rays.
The pulse size depends
upon the bunch size of the
electrons in the accelerator. Scientists from the
world over have agreed to
investigate the possibility
of building better x-ray
sources using a radically different approach.
Instead of using circular
tracks for the electrons, the new proposal envisages using linear accelerators
and free-electron lasers.
. The linear accelerators will speed
up the electrons and feed them into
free-electron lasers, where they will produce shorter and more energetic beams
of x-rays. The advantage of the linear
accelerator is that the bunch sizes of the
electrons are much smaller and the
duration much shorter compared to the
circular ring. The size of the electron
beam is also narrower in the linear
The electrons, when fed into
free-electron lasers, emit x-rays which
are much brighter than the other
devices. There is, however, a problem
with using the lasers: the mirrors in
these devices are not suitable for x-ray
wavelengths. The scientists, therefore,
propose to use a principle called SASE
(Self-Amplified Spontaneous Emission)
which will solve the problem. This
has, however, not been demonstrated
experimentally at the required
wavelengths. Though still in the design
stage, the fact that there is a consensus
in the international- community about
the new technology points to the
possibility that residual problems will be
solved. It is hoped that in the next 15-20
years, the x-ray community will be
using these fourth generation sources