 G'day, how you doing? My name is Adam. I teach chemistry and physics in Year 11 and 12 up in Darwin I got my degree from the Australian Defense Force Academy a bachelor of science I spent 12 years in the military Jump ship in Darwin and became a teacher and now other than teaching science I also like doing liquid nitrogen ice cream for school kids and launching model rockets right straight into an x-rays on one side the image of Wilhelm Roentgen. He is a German mechanical engineer who developed the x-ray tube and on the other side is a picture of his wife's hand handringing Which is a picture of his wife's hand with a ring and it was the first x-ray Officially released in the 22nd of December 1895. Okay quick bit of revision You'll need to remember that if you have two parallel plates Let's say for this example. This one's negative and this one's positive Then and you were to draw the field lines Then it's going to go this way because you've got to think where is that positive test charge gonna go as in the minuscule positive charge like charges repel and Opposite charge is a track now if you're an electron for example Which is going to be on this side and your E-minus You're gonna get want to get pushed away from the negative side and go over towards the positive And that is the basis for how an x-ray tube works Here's a very basic x-ray tube the electrons are released here And they go across the tube and smash into the metal target there It is done in a vacuum because if air was present in the tube It would prevent the tube from being able to do its work efficiently You don't want to air getting in the way of all the electrons leaving on the left and going through to the right To smash into the target metal the x-rays produced come out down the bottom And they can then be used for whatever purpose you intend them for is a more basic image of the x-ray tube What you can see here is that you've got your cathode Which is C and anode which is a the electrons leave the cathode Cross the electric field and arrive at the anode as they cross the electric field to accelerate remembering that F equals E Q so you've got the electric field strength E times the charge an electron and they're getting a force If it's getting a force F equals MA it must accelerate if it's accelerating It's gaining kinetic energy Those are like electrons gain a mountain of kinetic energy and then smash into the target there Most of it tends into heat hence why you need water and water out and the x-ray tubes require some form of heat reduction You'll note that there's a potential difference applied across the tube generally in tens of thousands of volts and Also a potential difference across the cathode Which allows a current to flow to which then boils off the electrons themselves Now the metal is in target that is in the x-ray tubes normally made of something really tough like tungsten because beta rays Radiation is really degrading So you need to make it out of something that's going to Live long enough to be commercially viable So that electron will fly across the tube and that'll come in and it'll come down at the atomic level and see a whole bunch of tungsten Nucleuses which have a mountain of tightly packed neutrons and protons in the center and of course the electron can get attracted by the protons and It's also going to have a bunch of a sea of electrons surrounding all these tungsten nuclei Now it's not just one electron with a few nuclei There's trillions of electrons crossing the tube and trillions of tungsten nuclei in the metal target And they're all coming along and they're all going to go into the tube Through the tube and into the metal target and they're going to have a variety of Results when the electrons arrive at the other side of the tube. They're going to have kinetic energy That energy will be transferred and the idea is to transfer it into x-rays to make a usable x-ray source You maximum frequency x-rays going to come from the electron smashing into a tungsten atom and stopping entirely all of its kinetic energy transferred to x-ray energy The electrons don't just have to smash into the nuclei itself They can also come close and and that's the example of This blue x-ray here where a an electron has come down and it's it's changed its direction Slowed down a little which is why we call this breaking radiation and it releases X-ray photon and the lower energy x-ray photon because that electron was further away from the nucleus The one in black has actually come a lot closer and changed direction in a much tighter curve and converted a bunch more kinetic energy into electromagnetic energy creating a x-ray of Higher frequency and higher energy and remembering that completely stopping the electron in its tracks Results in the maximum frequency x-ray now because you've got trillions of electrons smashing into trillions of tungsten nuclei There's a huge range of energies produced by the x-ray tube itself and that is something that we'll go to in greater detail later on. Thank you