The X-ray machine is one of the most common techniques for medical imaging today. It shoots high-energy radiation at any given destination, and penetrates selective materials.

It was first invented by accident in 1895 by German physicist, Wilhelm Roentgen.

The modern day X-ray machine has a very broad allotment of appliances to things like applied health, medicine, biology, and physics

When used on humans, it can penetrate the skin, and tissues; but not bone. To start off, these rays are invisible to our eyes, are more active than light photons. They are produced by allowing an electric current to pass through a vacuum tube. They can go through soft material such as skin but are stopped when they reach things like bones, tumours, metal objects etc. and will accumulate in these dense objects which will provide an image. The X-ray radiation act in a very similar fashion to light parcels, the more rays that are absorbed in a dense object, the clearer the picture will be.

X-rays are in many ways, very similar to visible light and light rays. Both are types of electromagnetic energy that is wavelike. The X-rays which are carried by particles called photons. The difference between the X-rays and visible light rays are the wavelengths of the rats which are also expressed as the energy level of the individual photons.
Visible light photons and X-ray photons are both created by the movement of electrons in atoms. When an electron drops to a lower electron shell or orbital, it needs to release some energy: therefore, it releases the excess energy in the form of a photon. The energy level of the photon varies and depends on how far the electron dropped or raised between shells.
Light photons are absorbed very well by the atoms in your body tissue. On the other side, radio waves don’t have enough energy to move electrons, so they just pass through most materials. However, X-ray photons have too much energy also allowing them to pass through most things.

When Wilhelm Conrad Roentgen ( the founder of the X-ray ) first discovered the X-ray by accident, he took the first picture of an X-ray to examine his wife's hand. The dark part in her hand is the ring, it is obviously the darkest object in the crude picture because gold is fairly denser than bone..

Advantages and disadvantages

X-rays are definitely one of the most renowned breakthroughs in medical, and scientific histories. However, as nothing in the world is perfect, there are some side effects to using the X-ray.

X-rays can still be harmful. In the early days of X-ray science, doctors and patients would be exposed to the beams for long periods of time and they eventually developed radiation illnesses; this is when the doctors knew something was wrong. 
The problem is that X-rays are a form of ionizing radiation. When normal light hits an atom, it can't change the atom in any profound way. But when an X-ray hits an atom, it can knock electrons off the atom to create an ion, an electrically-charged atom. The ions will knock other electrons around and form even more electrically-charged atoms.
An ion can lead to unnatural chemical reactions inside cells. Among other things, the charge can break DNA chains. These cells will either die or the DNA strand will become mutated. If enough cells die, then the body will contract various diseases. If the DNA mutates, a cell may become cancerous, and this cancer shall spread. If the mutation is in a sperm or an egg cell, it may lead to birth defects. All of these risks have made doctors use X-rays sparingly today. 
Even with these risks, X-ray scanning is still beneficial because it is safer than surgery. X-ray machines are an invaluable tool in medicine and a plus in security and scientific research. They are truly one of the most useful inventions ever.

Now that we know what X-rays do when they reach their destination and how they interact with material, the only question that remains is... How is an X-ray produced?






The centre of an X-ray machine is an electrode pair, a cathode and an anode, which is placed inside a glass vacuum tube. The cathode is a heated filament that a current is passed through; the current is what makes it hot. The heat shoots electrons off of the filament surface. The positive anode, a flat surface made of tungsten, pulls the electrons across the glass vacuum tube.

















The difference in the voltage between the cathode and anode is extremely high, so the electrons fly through the tube with a huge amount of force and speed. When a speeding electron collides with an atom on the anode, it knocks the electron onto the lower orbital. An electron in the higher level then falls to the one below it, releasing a photon from the extra energy. It's a big fall, so the photon has a high energy level. This high energy photon is an X-ray photon.

There is another way to make a photon without a free electron smashing into another secured electron. An atom's nucleus can pull a high-speed electron enough to change its course, almost like a comet whipping around the sun. The electron decelerates and changes direction as it speeds past the atom. This change in speed causes the electron to emit additional energy in the form of an X-ray photon.









The free electron crashes with the tungsten atom, which knocks an electron out of a lower orbital. A higher orbital electron fills the empty position, releasing the excess energy as photons


The free electron is attracted to the incoming tungsten atom nucleus. As the electron passes, the nucleus slightly changes it's course. The electron  will lose energy, but it will be released as an X-ray photon.



The entire mechanism is covered by a thick lead barrier. This keeps the X-rays from escaping in all directions. A small cut out in the shield lets some of the X-ray photons escape in a thin beam. The photons escape through a line-up of filters on its way to the patient. A capture device on the other side of the patient records the pattern of light that passes all the way through the person’s body making a image on a common imaging film.

There are two processes that take place during the conversion of the X-ray

 The first is bremsstrahlung ( which translates into "breaking rays") and it occurs when the electrons moving at high speed are slowed or put to a full halt by forces of any atom it comes across. The second is the K-shell emission where the once-heavy atom is in the lowest state of energy it can go. Both of these processes are vital in X-ray production although it is often preferred to use the latter over the first.










Clayton Ellis, Donald Lacy, Catherine Little, Heather Mace, Lionel Sandner, Pauline Webb, Otto Wevers, Sandy Wohl. Investigating Science 10, Canada, Pearson Canada (2009)

Harris, Tom.  "How X-rays Work"  26 March 2002.  HowStuffWorks.com. <http://science.howstuffworks.com/x-ray.htm>  11 April 2012.

Author Unknown. "Making X-rays" Date unknown. Colorado.edu. http://www.colorado.edu/physics/2000/xray/making_xrays.html 11 April 2012

Author Unknown. "What is Bremsstrahlung?" Date unkown. ndt-en.org.

http://www.ndt-ed.org/EducationResources/HighSchool/Radiography/bremsstrahlung_popup.htm 11 April 2012

Author Unknown. "Advantages of X-ray". Date unknown. medindia.net. http://www.medindia.net/patients/patientinfo/x-ray_advantages.htm 11 April 2012

Author Unknown. "K-shell emission". Date unknown. Colorado.edu. http://www.colorado.edu/physics/2000/xray/making_xrays3.html 11 April 2012