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G. H. Raisoni College of Engineering
Department of First Year Engineering
(Section: G Department: Mechanical engineering)
Subject: Bio Systems in Engineering
TAE II: Technical Presentation
Topic: X-ray
Presented by:
Rupesh Kumar
Shubham dhore
Shivam singh
Yash bais
2. X-rays were discovered by the German physicist W. C. Röntgen
in 1895.
When he accidentally noticed that fluorescent materials showed
a faint glow when placed near a cathode-ray tube powered by a high
voltage induction coil.
Although others had observed similar phenomena earlier, Röntgen
was the first one who concluded that he had found “a new kind of
rays”. He called them “X-rays” (X = unknown) and began a
systematic research on their properties.
His work was so thorough that it took seventeen years until
significant new facts became known. Some scientists thought that
X-rays were a kind of ultraviolet light, but nobody was able to prove it
at that time.
Finally, crystal diffraction experiments done by M. v. Laue in
1912 confirmed that X-rays are electromagnetic waves.
Production And Characteristics Of X-ray
3. Production of x-ray
X-ray production whenever electrons of high energy strike a heavy
metal target, like tungsten or copper.
When electrons hit this material, some of the electrons will approach
the nucleus of the metal atoms where they are deflected because of there
opposite charges (electrons are negative and the nucleus is positive, so
the electrons are attracted to the nucleus).
This deflection causes the energy of the electron to decrease, and this
decrease in energy then results in forming an x-ray.
X-rays are produced when high energetic electrons interact with
matter.
4. Current estimates show that there are approximately 650
medical and dental X-ray examinations per 1000 patients per year.
The kinetic energy of electron is converted into electromagnetic
energy of electron.
6. Some Facts about X-Rays
With a wavelength of approx. 10nm to 0.001nm.
X-rays occupy the range between UV light and gamma rays in
the electromagnetic spectrum.
The definition of the upper and lower wavelength limit is more
or less arbitrary and not marked by a sudden change of properties.
X-rays with a short wavelength, for example, overlap with
gamma rays of long wavelength.
Radiation in this region is usually named after the mechanism of
emission.
Gamma rays are released by nuclear processes, X-rays are
emitted when fast electrons collide with matter.
Technically, X-rays are produced by means of an X-ray tube, a
simple form of a linear particle accelerator.
8. The X-ray tube provides an environment for X-ray
production via bremsstrahlimg and characteristic radiation
mechanisms.
9. The intensity of the electron beam determines the
intensity of the X-ray radiation. The electron energy
determines the shape of the bremsstrahlungs spectrum, in
particular the endpoint of the spectrum. Low energy X-rays
are absorbed in the tube material.
20. X-ray sources abound around us. They include the
following
Natural X-ray sources
1) Astrophysical X-ray source, as viewed in X-ray astronom
2) X-ray background
3) Naturally occurring radionuclide
Artificial X-ray sources
1) Radiopharmaceuticals in radiopharmacology
2) Radioactive tracer
3) Brachytherapy
4) X-ray tube, a vacuum tube that produces X-rays when
current flows through it
5)X-ray laser
6) X-ray generator, any of various devices using X-ray tubes,
lasers, or radioisotopes
7)Synchrotron, which produces X-rays as synchrotron
radiation
8)Cyclotron, which produces X-rays as cyclotron radiation
22. Other X-ray sources
Synchrotron
need electron or positron beam orbiting in a ring
beam is bent by magnetic field
x-ray emission at bend
Advantages
10-4 - 10-5 radians
divergence
(3-5 mm @ 4 m)
high brilliance
wavelength tunable
24. Other X-ray sources
Synchrotron
need electron or positron beam orbiting in a ring
beam is bent by magnetic field
x-ray emission at bend
Advantages
10-4 - 10-5 rad
divergence
(3-5 mm @ 4 m)
high brilliance
wavelength tunable
high signal/noise ratio
25. Properties of X-ray
X-ray photons carry enough energy to ionizee atoms and
disrupt molecular bonds. This makes it a type of ionizing
radiation, and therefore harmful to living tissue. A very high
radiation dose over a short amount of time causes radiation
sickness, while lower doses can give an increased risk of
radiation-induced cancer. In medical imaging this increased
cancer risk is generally greatly outweighed by the benefits of
the examination. The ionizing capability of X-rays can be
utilized in cancer treatmentto kill malignant cells using
radiation therapy. It is also used for material characterization
using X-ray spectroscopy.
Hard X-rays can traverse relatively thick objects without being
much absorbed or scattered. For this reason
27. X-rays are widely used to image the inside of visually opaque
objects. The most often seen applications are in medical
radiography and airport security scanners, but similar
techniques are also important in industry (e.g. industrial
radiography and industrial CT scanning) and research (e.g.
small animal CT). The penetration depth varies with several
orders of magnitude over the X-ray spectrum. This allows the
photon energy to be adjusted for the application so as to give
sufficient transmission through the object and at the same
time good contrast in the image.
X-rays have much shorter wavelength than visible light,
which makes it possible to probe structures much smaller
than what can be seen using a normal microscope. This can
be used in X-ray microscopy to acquire high resolution
images, but also in X-ray crystallography to determine the
positions of atoms in crystals.
