Using these “lasers” we punch a hole…

Austin Power’s nemesis Dr Evil was always up to no good, punching holes in ‘the protective layer around the Earth, which we scientists call the “Ozone Layer”’ with his ‘sophisticated heat beam which we called a “laser”’.

"Before" - One of the gold tubes, in a holder, before we were let loose with the laser. Photo: Y. Nishimura.

“Before” – One of the gold tubes, in a holder, before we were let loose with the laser. Photo: Y. Nishimura.

Of course we would never dream of doing anything so dastardly. But someone has let us loose with a laser and a gold tube, and we’ve been making holes in the gold with the laser!

No, we haven’t branched out into making jewellery in our spare time! It is all in the name of science and research!

In July Henner Busemann wrote an article on this blog about the Hayabusa mission. This Japanese mission collected samples from the asteroid Itokawa and returned them to Earth for analysis.

We are currently working in collaboration with Prof Keisuke Nagao from the School of Science at The University of Tokyo to analyse the krypton and xenon isotopic composition of grains collected by the Hayabusa mission.

"After" - Gold tube after attempts to make holes in it with the laser. 2 separate holes can be seen at the lefthand end of the tube. Photo: Y. Nishimura.

“After” – Gold tube after attempts to make holes in it with the laser. 2 separate holes can be seen at the left side of the tube. Photo: Y. Nishimura.

Only a relatively small number of grains were collected by the mission, therefore they are very precious and scientists want to get as much information as possible from each grain. They won’t give us some grains to zap with our laser and just measure xenon and krypton, because when we zap a grain we melt it and then it’s no use to anyone else. So Prof Nagao is heating the grains and extracting all the noble gases – he then analyses the helium, neon and argon, and traps the xenon and krypton in small gold tubes for us to analyse. This way instead of only analysing some of the noble gases in a single grain– either helium, neon and argon in Tokyo or krypton and xenon in Manchester – all the noble gases can be analysed and more information is extracted from each grain.

The gold tubes are sealed before being sent from Japan to the UK (I volunteered to go and collect them personally, and perhaps spend a little time exploring Japan while I was at it, but apparently a courier is cheaper and quicker!)

Of course this all sounds much simpler than it actually is!

Once the tubes have made their journey to Manchester, we need to find a way of opening those tubes again, to let the gas out again, when they are inside the spectrometer. Hmmm! How can we open something that is in a vacuum in a spectrometer? This is where the lasers come in…

We’ve been testing using an ultra violet laser to effectively drill a hole into the gold – a process known as ablation. After a few false starts, a few burnt lenses and burnt windows, we finally found the best set-up to make a hole in the gold. It takes a couple of hundred shots with a high energy beam, focused to a small spot.

One of the gold tubes inside the sample port. Looking at the base of the port, I think we hit that with the laser quite a few times!

One of the gold tubes inside the sample port. Looking at the base of the port, I think we hit that with the laser quite a few times!

So the next step is to practise on some “fake” samples – gold tubes that contain known amounts of xenon and krypton. If that’s successful, hopefully we’ll be let lose on the real tubes that actually contain the gas from the precious samples.

The Japanese group will be presenting their initial results at the 44th Lunar and Planetary Science Conference in Houston in March. Watch this space for updates on our progress…

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About Sarah Crowther

I'm a Post Doc in the Isotope Geochemistry and Cosmochemistry group. I study xenon isotope ratios using the RELAX mass spectrometer, to try to learn more about the origins and evolution of our solar system. I look at a wide range of samples from solar wind returned by NASA's Genesis mission to zircons (some of the oldest known terrestrial rocks), from meteorites to presolar grains.
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One Response to Using these “lasers” we punch a hole…

  1. Pingback: outReaching the new generation of planetary scientists | Earth & Solar System

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