Meet the scientists!

What you would do with the world’s highest intensity laser?

The most common answer I hear to this question is “Shoot something with it!” which is pretty much exactly what I think too and conveniently lots of other scientists… so we do! We fire a laser called Astra Gemini at all kinds of things from wafer thin pieces of metal and plastic, puffs of hydrogen gas, jets of liquid and even into empty space itself!

Why do we want to shoot stuff with the world’s highest intensity laser? I do it because we don’t know what will happen and I think that is pretty exciting! So some things we have found out so far…

1. Bye-bye target! The Astra Gemini laser is so intense that any material put at it’s focus immediately has it’s atoms ripped apart. This creates a fouth state of matter which we called plasma. Plasma is what the sun and all the other stars are made of; in fact 99.99% of the universe is plasma and we are the unusual bit being made of solid, liquid and gas. 

2. Hot hot hot! This laser does not stop at just tearing apart the atoms, it still has so much ‘umph’ left that the plasma it creates has temperature similar only to that inside the sun. The laser is so intense it drives the broken atom pieces (that we often call electrons and ions) with such force that they gather speeds close to the speed of the laser pulse itself… the speed of light!

3. Wow…Strange things coming through! This is where it gets really interesting. The laser has been used to shoot beams of electrons straight out of the plasma, beams of ions and very high energy x-rays too. In addition, we now have people predicting that we could rip matter out of empty space itself! So if we focused the laser down into empty space (referred to as the vacuum) we’d see particles fly out! This is something i can not wait to see, but it’s true you don’t get something for nothing… you need a whopping great big laser to make it happen! 

So this is what I do. I work alongside other scientists, from around the world, that have asked themselves ‘What can we do with the world’s most intense laser?’ and then suggested experiments and been given time to come and play (eh..hmm…) work with the Astra Gemini laser at the Rutherford Appleton Laboratory.  I then help them plan, prepare and try out their ideas and we get to learn together the answer to ‘I wonder what would happen if I fired the laser at….’

Ideas for new experiments are always welcome…

Getting ready for shots: The other scientists and I sit and discuss our plan for shooting the laser that day. As always everyone wants to fire the laser as soon as possible but unfortunately it needs to be turned on first and we have a team of laser experts who know how to make it as powerful as possible.

Aiming at our target: Once they have set it up they hand it over to me and I take a team inside what we call the target area where there is an interaction chamber in which our targets for the day will be aligned. We check the laser focal spot which is a hundred times smaller than the thickness of a human hair, at 1micron in diameter. We then check all the cameras and other detectors are aimed and timed correctly so we will see what happens when we fire. We cannot be inside the area ourselves, during the shot, due to it being too hazardous. Also the duration of the shot is so short that without recording you would definitely miss it. In one second light can travel from the earth to the moon, our laser pulse is 50femtoseconds long and in that time light can barely pass the thickness of a spiderweb. 

Fire! This is the most exciting bit! All the hard work of setting it up has been done and now we get to fire the laser. The final checks are made that everything is in place and after everyone running detectors has said “Ready!” we press the countdown button. We then wait anything from 60seconds to 10seconds and in the last 5 seconds we have a countdown and would hear something like…

“5,4,3,2,1… shot fired! 12 Joules on target. Shot number 25234. The target has gone so we definitely hit something! What did everyone see then?” 

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What would you like to see demonstrated? I would like to make something that helps people understand something they are interested in and what better way to find the most interesting question than by listening to what you’d like to know. I would also like to make a you tube video of the demonstration so everyone could have access to understanding something exciting about the world that they didn’t know before.