Question: do your jobs involve any quantum physics, as i am interested in the happenings of the micro-world?

Emma Ryan answered on 7 Mar 2017:

Hey, Giraffe,
I used quantum physics to test my samples so I can look at its composition (the material it’s made out of) and its microstructure (this is sort of how the atoms are placed in the material).

Below is a brief description of a technique I use called XPS. You can find out more on my profile.

I use very specialised bits of equipment that are based on quantum theory. I am more than happy to go into it if you’re interested in Quantum Physics, please read below. Apologies if I go too far, I do not know much you’ve learned at school.

So atoms are made up of neutrons, protons and electrons (I’m not going to go more complicated than that at the moment). The neutrons and protons are found in the nucelus and the electrons are found in shells around the nucleus – this really means an orbit like how the Earth goes round the Sun. These shells are a description of the electron’s energy level and there are only certain energies an electron can be (also known as quantum states).

Each element has a different number of electrons and this affects the energy levels (due to electron configuration). The binding energy is a term used to describe the energy required to move the electron away from the nucleus (the positive protons and the negative electrons are attracted to each other and this binds them together). Each element has different binding energies (because of all the different forces being applied). I have described this bit horribly but I hope you get the idea.

This can help us in lots of different ways. We can fire x-rays on our samples which will give the electrons enough energy to move away from the nucleus. We then measure the kinetic energy of the electrons that we detect. We know how much energy the original x-ray beam has and how much energy it must’ve given the electrons. By subtracting the kinetic energy away from the beam energy, we then know the binding energy (conservation of energy law applies) and can then work out which element is in the sample as, said before, each element has a different binding energy. This is called x-ray photoelectron spectroscopy. It is a little bit more complicated than this due to collisions and the necessary modelling but this is the basics.

I hope you found it interesting and it showed how Physics can be applied to Engineering. If you would like to know more about any more of these concepts, I’m sure Google and Wikipedia is a good starting point. Things to search:
Binding energy
Photoelectric Effect
Electron Configuration
Einstein
Rutherford
Bohr
Electron shells
Quantum