X-RAYS: Properties, Uses, Scientists and Discovery

This presentation provides an overview of X-rays, including their properties, uses, scientists associated with their discovery, and how they were discovered. X-rays are electromagnetic waves that have high energy and can pass through various objects, including the human body. They are used in various fields, including medicine, industry, and security.

X-RAYS
• X-rays are one of the waves that form the electromagnetic spectrum
and unlike for the case of visible light, they have higher amounts of
energy and thus able to pass through various objects among them
the human body (Curry 2010, p. 617).
• Photographic films are one of the types of x-ray detectors even
though there exist many other detector types that are useful in the
production of digital images.
• X-rays resulting from x-ray detection processes are called
radiographs.
• X-rays are produced when a beam of electrons moving at very high
speeds strike a metal target.

• These electrons are generated from the heated filament and
directed towards the metal target by high voltages from the tube
(Singh 2015, p. 215).
• Another way in which x-rays can be produced is during the collision
between electrons and atoms and the nuclei of the metal target.

Properties of x-rays
• X-rays are electromagnetic waves and thereby a part of the
electromagnetic spectrum.
• Just like other waves in the spectrum, x-rays are transverse waves
i.e. their oscillations are perpendicular to the energy transfer
direction. Other properties include;
• X-rays;
 have a very short wavelength, almost the same size as that of
the diameter of an atom:
• Wavelength refers to the distance between two successive
troughs or crests and is usually measured in the wave
direction.
• The crest refers to the highest point of the wave while the
trough refers to the lowest point of the same wave (Dance
2010, p. 589).
• Being a measure of distance/length, wavelength is measured
in units including meters, nanometers, and millimeters
among other units. The wavelength range of x-rays is from
0.01 to 10nm

 are absorbed by bone or metal
 are able to pass through, absorbed or transmitted
 cause ionization when they pass through molecules:
Ionization defines the process by which electrical neutral
molecules or atoms gain or lose electrical charge. It is one of
the main ways through which energy is transferred by
radiation in particles such as x-rays.
 have a speed of 1,860,000 miles/second which is the same
speed as that of visible light (Podgorsak 2013, p. 369)
 cannot be reflected, refracted or deflected by an electric field
or a magnet
 produce electric fields at right angles to their propagation
paths
 do not require a medium for propagation

Uses of x-rays
• Airport security: Airports are fitted with a security system of x-rays
used in the scanning of the luggage and travelers to fish out any
dangerous items. In other areas, there are full body x-ray scans that
were used as additional measures for security.
• Radiation therapy: X-rays play a very fundamental role in the fight
against cancer (Podgorsak 2013, p. 448). With its high radiation
properties, x-rays are used in the killing and damaging of cancer
cells and related shrink tumors. The treatment is done either from
outside the body or a radioactive material inserted into the body at
a close range to the targeted cancer cells.
• Used in the business and industry in the identification of any flaws
or defects in the engine or engine parts in a nondestructive way. On
the same note, oil or gas pipes sections can easily be monitored for
any defects or cracks (Dux 2011, p. 158).

• Used in diagnostic purposes in medicine and dentistry: the waves
work on the principle that body parts such as the teeth and bones
are of higher density and thus less transparent to x-rays as
compared to the other parts of the body

Scientist associated with x-rays
• The invention of x-rays involved a series of scientists and
researchers over a long period of time.
• One of such scientists was Johann Hottorf. Johann Hottorf lived
between 1824 and 1914, born in Bonn and dies in Munster,
Germany.
• Johann Hottorf who was a German mechanical engineer and a
physicist was the first scientist to calculate the capacity of
electricity of charged atoms and molecules.
• He was the first person to formulate the numbers of ion transport
and their measurement method (Sakdinawat 2017, p. 897).
• He also noted that the rays of energy extend from a negative
electrode and making flickers of rays that stuck on the walls of the
tube of glass-later called x-rays.

• Johann Hottorf found out that if a paper is wrapped with
photographic plates is put near the cathode ray tube, the paper
would be unaccountably flawed or fogged even though the paper
had not be exposed to light.
• He showed that a shadow is cast at the tube end across from the
cathode when a solid object is put between the anode and cathode
of a cathode tube (O'Flynn 2012, p. 333).
• This was an indication that the cathode releases rays or beams
hence the name cathode-ray tubes.
• Johann Hottorf worked together with William Crookes in making the
findings.
• During his time as the professor of physics and chemistry at the
University of Munster, he did an investigation into the light spectra
of vapors and gases and studied the passage of electricity through
gases.

• He made new inventions in the cathode rays properties. In 1869 he
discovered that due to different gases and pressure, cathode rays
would glow (Callaway 2013, p. 458). I
• t was at this time when he also noticed that the shadow of an object
would appear if the object is placed between the tube’s illuminating
side and the cathode.
• These developments by him led to the development of cathode ray
tubes and x-rays.
• The creation of a vacuum tube diode required a measurement of the
current that was passing through the vacuum tube.
• This was a development by Johann Hottorf.

Discovery of X-rays
• X-rays were invented during a study on cathode rays by a scientist
called Wilhelm Conrad (Srivastava 2013, p. 236).
• The experiment was about passing an electric current through gases
at extraordinarily low pressures in which certain rays were observed
to be emitted as the current passed through the discharge tube
(Dance 2010, p. 654).
• The experiment was furthered by working in a completely dark
room and the discharge tube being well covered.
• Rays which illuminated a screen of barium platinocyanide were
emitted and the screen became fluorescent despite being put in
the path of the rays, about two meters away from the tube of
discharge.
• The experiment continued but now with the use of photographic
plates that were used in the capturing of the images of the various
objects of different thicknesses. Subsequent research found out
that x-ray beam is generated by the impact that the cathode rays
have on the materials placed on the path of the rays (Dux 2011, p.
168).

References
• Callaway, WJ 2013, Mosby's Comprehensive Review of Radiography -
E-Book: The Complete Study Guide and Career Planner, Elsevier
Health Sciences, New York.
• Curry, TS 2010, Christensen's Physics of Diagnostic Radiology,
Lippincott Williams & Wilkins, Manchester.
• Dance, JB 2010, X-rays from laser plasmas: generation and
applications, Wiley, Paris.
• Dux, A 2011, Chest X-rays for Medical Students, John Wiley & Sons,
Chicago.
• Duxbury, A 2010, Practical Radiotherapy: Physics and Equipment,
John Wiley & Sons, New Delhi.
• O'Flynn, K 2012, Imaging and Technology in Urology: Principles and
Clinical Applications, Springer Science & Business Media, New York.

• Podgorsak, EB 2013, Compendium to Radiation Physics for Medical
Physicists: 300 Problems and Solutio, Springer Science & Business
Media, New York.
• Sakdinawat, A 2017, X-Rays and Extreme Ultraviolet Radiation:
Principles and Applications, Cambridge University Press, London.
• Singh, M& 2015, Engg Physics, Tata McGraw-Hill Education, Shanghai.
• Srivastava, SK 2013, Engineering Physics Theory And Experiments,
New Age International, Paris.