Moderator: To kick off, I challenge you to tell me one thing related to particle physics I wont know, or at least will not have heard much about in the news.

Scott – STFC physicist: I have a fact that I learnt the other day. I’ve always known how screamingly, horrifically strong the radiation is coming off our target, but I recently learnt that it’s about a thousand times stronger than that! Like: serious melt your face off insta-death levels (if unshielded). Thankfully our radiation shielding is perfect and the dose rates are below background just outside the shielding. It’s actually safer to stand next to it than to live in Cornwall or Glasgow with lots of granite bedrock!

Moderator: Why is the target so radioactive? Whats it made of?

Scott: We’re smashing very powerful and relativistic proton beam into a tunsten target to generate neutrons for materials science. Neutrons are fairly nasty at the best of times… and those are the things we want to make! The tungsten also undergoes all kinds of other nuclear processes. Ergo Gamma-rays and prompt fission products.

Moderator: “Seriously melt your face off insta-death levels?” I’m wondering if that is an official SI unit reading?

Scott: If you want a proper unit: it’s 200,000 Sieverts. One Sv is guaranteed quick death, so hundreds of thousands more is utterly terrifying.

Moderator: Yeah, insta-death level will do nicely.

Lucy: I think it is much easier to understand than Sieverts
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Meirin – CERN physicist: Hi, I prepare CERN data for use in educating students of about 16 years and older

Teacher: Hello everyone! Thanks for the introductions. I’m a high school physics teacher – this is my first fully qualified year and I am teaching up to advanced higher level. @Meirin what sort of data are you preparing for students?

Meirin: Data to teach students about particle physics but also about transferable skills like programming and data analysis

Teacher: Is that something that will be publicly available? I’d be keen to get my classes involved. Our school doesn’t have great IT at the moment but we will soon be getting iPads for all pupils

Meirin: Yes it’s all on opendata.atlas.cern !

Teacher: I haven’t looked at the website in much detail yet, but what sort of activities would be possible using the data?

Meirin: The “get started” section teaches how histograms are used in particle physics by searching for the Higgs boson decaying to W bosons. The “web analysis” section introduces how programming is used in particle physics by measuring properties of particles such as the Z-boson. The “Data & tools” allows download of all available data to do some proper programming projects to e.g. search for Beyond Standard Model particles

Teacher: Thanks. Time permitting I’d love my pupils to use some real particle physics data rather than just answering textbook questions. Pupils can also struggle to understand what a career in particle physics might look like so using real data from ATLAS would help with that too

Meirin: Honestly it’s such a good introduction to research. I did my masters on ATLAS Open Data so wouldn’t be here without!

Teacher: That’s really good to know, it will be really helpful to tell my pupils that.
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Teacher: I’m interested to hear the routes you each took into your current career? My pupils definitely don’t appreciate the wide range of opportunities that studying sciences can provide

Scott – STFC physicist: I studied undergrad astrophysics at Uni. After that got a job on STFC’s graduate scheme on a completely different subject: accelerators. Been here ever since and am now group leader

Susan – Neutrino physicist: Did Astronomy and Natural Philosophy (as they still called it then) at Glasgow. Then PhD (also with Glasgow) working at DESY in Hamburg. Then postdoc with Rutherford Lab, also based at DESY, followed by postdoc at SLAC in California, before landing lecturer post at Sheffield

Savannah – CERN physicist: I didn’t know what I wanted to do for ages but always enjoyed maths and science so did these subjects at school. I then studied physics at Manchester University (integrated master’s) and now I’m doing a PhD there too 🙂

Edoardo – Theoretical physicist: I liked scientific subjects at high school and then got into physics at university. In the last year I went for theoretical topics.

Anne – Dark matter physicist: I really enjoyed (and was good at) maths at school, but wanted to apply it to something interesting rather than doing maths for maths sake. And I discovered cosmology via popular science books and documentaries. I then did Physics at Oxford followed by a PhD in early Universe cosmology at Sussex.
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Teacher: What would you say the easiest way to show what you do to school age children would be?

Lucy – Particle physicist: I spend my days doing programming and maths/algebra! But we always try to work with pictures/videos and something hands-on to get students thinking. We have an exhibit with a galton board containing a hidden shape (which changes the way the balls fall through and hence the pattern at the bottom) and computer programmes that simulate this.

You have to try different shapes until you find the one that gives a similar result to the real experiment. This is similar to how we understand particle physics experiments – we build a computer model of them and predict what we think we will see as the outcome. Then compare that to the experimental results. Since with particle physics we can’t see what is happening when e.g. two protons collide but we can get a measurable outcome (electrons, photons, quarks/gluons and their directions and energies)

Teacher: So are you getting to build the computer models? The shape things is like a simple thing we have in the cupboard actually, different weighted tins, I could try them with the pupils for a variation on that

Lucy: I don’t personally build them, but I am working on calculations that will (hopefully!) help improve them. Many others in my research group do work on the programmes used to understand CERN’s results from the LHC

Teacher: So photons, quarks and gluons – when describing protons, electrons and neutrons we basically speak about mass, where they are and what their charge is – where would they fit into this model for me and my pupils

Lucy: photos have no mass and are the particles of light – so a beam of light is many many photons. Quarks and gluons are what you find if you break apart protons and neutrons. On the most basic level protons and neutrons are made of three quarks each, and gluons are the “glue” that holds them together (they are a force particle like photons)

Teacher: So would the quarks be equal in size?

Lucy: Quarks have an electric charge of either 2/3 or -1/3 (there are two types) and gluons have no electric charge, neither do photons

Teacher: What are the quarks doing? Is it like a polymer unit type thing where they are all needed to carry out the role of protons having a positive charge and neutrons having a neutral charge or is that too simplified?

Lucy: Sort of yes, in that a proton “gets” its charge from the quarks within it, and a neutron contains charged quarks but is overall neutral. It’s similar to breaking an atom down into electrons, protons and neutrons – quarks and gluons are the “insides” of the protons and neutrons

Teacher: Would you then find quarks and gluons isolated anywhere or can you only find them when you blast the neutrons and protons apart?

Lucy: You can’t find them isolated! Quarks are always in at least pairs (known as mesons), or in threes like the protons/neutrons. You can also get more quarks bonded together but these have only been seen at the LHC. And wherever there are quarks there are gluons holding them together 🙂 Gluons carry what’s known as the strong force – which is much stronger than the other forces like electromagnetism. And it’s partly because it’s so strong that you don’t find the particles alone

Teacher: So what type of a substance are gluons made from? like biological enzymes where they have a specific shape relating to the quark or like a bond in chemistry?

Lucy: Gluons are made of gluons if that makes any sense? They can’t be broken down (as far as we know). They are like a bond in chemistry (which works between two differently electrically charged particles, and the bond is made of photons), so gluons are the bonding between quarks
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Teacher: What one thing do you think is the most important thing about stars and planets which school kids should learn – there is so much information and limited time

Scott – STFC physicist: I think it’s important to understand just how mind-bogglingly huge space is. It takes days just to get to the moon. There is enough space between us and the moon to fit all the other planets in. And that’s just the moon! Saturn, for example, is over a billion miles away

There’s such a lot of nothing in space that it’s mind-boggling. We’re brought up seeing the Millenium Falcon dodging asteroids, when in reality you would fly through the asteroid belt on your way to Jupiter and not even see anything out the window!

This website is an excellent demonstration of the scale of things. Really accessible and puts everything into perspective: https://joshworth.com/dev/pixelspace/pixelspace_solarsystem.html

Especially useful for kids used to scrolling endlessly on their smartphones: now they can scroll endlessly through space! 🙂

Teacher: Ha ha excellent!
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