Smile! You're on camera!

Starting this new blog, I got lucky. What was I going to wow everyone with? Come on physicists, give me your best! And what was in my mailbox? Physicists film the electron.

Now every reporter needs to learn that releases like these are more complicated than at first glance, but my first thought was “cool”! I have to admit, I thought of a little shiny ball zooming around. Actually I thought of a bubble chamber, check that out here: http://en.wikipedia.org/wiki/Bubble_chamber. But it’s a little more complicated. If you ever took chemistry, you know that an electron is charge, or really, it’s a charged particle smaller than an atom. An atom is made of these guys and protons. Its mass is itty bitty, a thousandth the size of the tiniest atom, and as far as we know, it cannot be broken down into any smaller units. But can we actually see one?

Electrons live around atoms, zooming around. To get one you need to detach it from an atom. Before, it had been impossible to actually photograph an electron because they move so fast and the extremely short flashes you need weren’t available.

It takes about 150 attoseconds for an electron to circle the nucleus of an atom. The definition of an attosecond is one quintrillionth of a second. Yes, that’s a word. But I like this quote better: “an attosecond is related to a second as a second is related to the age of the universe,” according to Johan Mauritsson, an assistant professor in atomic physics at the Faculty of Engineering, Lund University. He is one of seven researchers behind the study.

Scientists at Lund University in Sweden have the technology that can capture something going this fast. They call it a stroboscope (another device like it captures still images of a hummingbird’s wings). The researchers synchronized light pulses with the oscillations of a weak infrared laser. They made these pulses kick a cloud of helium atoms (where the electrons came from) at a precise time. Each attosecond pulse released a few electrons, some of which were thrown back against their atoms before being pushed sideways and detected.

After many, many of these events, the team was able to get some clean images of the “quantum state of electrons ionized at a single moment in their laser oscillation cycle.” This made a bullseye pattern, which you can see in the video.

"The length of the film corresponds to a single oscillation of the light, but the speed has then been ratcheted down considerably so that we can watch it. The filmed sequence shows the energy distribution of the electron and is therefore not a film in the usual sense."
http://www.atto.fysik.lth.se/

“By taking several pictures of exactly the same moment in the process, it’s possible to create stronger, but still sharp, images. A precondition is for the process to be repeated in an identical manner, which is the case regarding the movement of an electron in a ray of light. We started with a so-called stroboscope. A stroboscope enables us to “freeze” a periodic movement, like capturing a hummingbird flapping its wings. You then take several pictures when the wings are in the same position, such as at the top, and the picture will turn out clear, despite the rapid motion,” clarifies Johan Mauritsson.

No shiny ball, but still pretty neat.

Later in the week I’ll talk about Enceladus. Then, who knows?