Monday, 29 November 2010

The Real Deal

Over the next few weeks I'm hoping to build up an idea of the "real deal" of what it is like to work as a female research scientist. I'm looking for women from all levels of career - whether a PhD student or professor - and from lots of different research areas. The only pre-requisite is that you are passionate about your subject and have an interesting story to tell!

If you or someone you know fits this category - please leave me a comment. I'll be conducting short interviews via email.

To give you a taster, a couple of questions you might get asked include:

- Why did you become a scientist?
- What is it that makes you want to come to work each day?
- What is the best/worst thing about your job?
- What do you enjoy other than science?

Wednesday, 17 November 2010

Physics and music: what is the connection?

Reading a few popular science books when I was younger, I remember learning that Richard Feynman played the bongo and Albert Einstein played the violin. Since then I’ve discovered many more examples of brilliant physicists who were also musicians. So is there something about the skills, mindset or attitude of physicists that make them good musicians?
Today I discovered that a group of people at CERN who work on the ATLAS experiment have recorded an album called Resonance. Even though I used to work on ATLAS, just for the record, I’m not involved the album! That said, I’m still going to give it a blatant plug – so go and buy it, proceeds go to charity.
Resonance - click the image for their website.

Most of my friends and colleagues who I’ve studied or worked with in physics are musical. I know so many singers, guitarists and pianists that it’s somewhat surprising I hadn’t really noticed it before. My only excuse for not noticing is that maybe other common themes - like the high proportion of men or the tendency for many physicists to ignore the entire fashion industry (their own peril) – were more noticeable to me at the time.
Perhaps I haven’t noticed because I am musical myself so I’ve been used to having lots of musical friends. Whatever the reason, I suppose I should have realised the trend when I found out that the physics department at Oxford have their own choir. The choir only rehearses and performs at Christmas for the departmental carol service, but I think its existence says something about the tendency for physicists to be musical. But why is that the case?
If we wanted to be pragmatic we would hold off the question “why?” until a proper study is done of the statistical significance of physicists who are musical. If you know of such a study – leave me a comment!
For the sake of argument though, if such a study revealed the trend that physicists are, indeed, more musical than the general population, then the “why?” question becomes more important.
In many ways, being a physicist is like being a musician. It requires a lot of patience, a willingness to get things wrong and to learn from mistakes. Research itself is often quite a creative process. In a similar way to music it requires its own language and way of expressing itself.
On the other hand, when I sing or when I hear my friends play I’m sure they aren’t thinking about the fractional relationships between frequencies or the exact subdivisions of rhythms. Most of them are probably using music as a bit of a release from their everyday activities. In this sense, being a physicist is completely different from being a musician.
My opinion? Many physicists will tell you that there is something beautiful and elegant about the workings of the universe, even if we don’t fully understand it. Perhaps it is the similarity between this and the beauty of good music that draws us in? It can be hard to admit it, but maybe we physicists are just a little bit romantic.
 

Tuesday, 9 November 2010

Could I use my mobile phone as a particle accelerator?

We all know the sound well. All is peaceful, driving along in the car or sitting in a room listening to a speaker… and all the sudden “blip bzzzzz blaaaaar bzzzzzz”. Something starts buzzing. We all know why; there’s a mobile phone nearby. This noise has somehow become a part of our everyday lives but why does it happen?
If you were an early mobile phone user you might have noticed that they didn’t have the same effect – so it has to do with the GSM phones that we (mostly) use now. There are three things which need to happen together the cause the buzzing:
1.     A pulsing radio transmitter
To connect to the tower and your network, your mobile phone sends out little bursts or pulses of information around 200 times per second (200 Hz). Each of the pulses have a frequency in the radio range, so the signals themselves oscillate millions of times per second – in the MHz range. So this is a ‘pulsing radio transmitter’.
2.     Relatively strong power
Compared to original analog phones, newer mobile phones give out a stronger signal strength as they don’t give it out continuously – as I said above it is ‘pulsed’. For most GSM networks the peak power of the pulses is about 8 times the average power. So we have a relatively strong power source.
3.     Close to a particular type of electronic element
The particular element in the circuit of a speaker which picks up the signal can vary, but it’s usually some solid state device like a diode or a transistor. When the strong pulsed radio signal is near it, the circuit element can detect the pulses and amplify, then send them to the speaker so we can hear the pulsed signal.
The pulses which are amplified come at 200 Hz, and since Middle C on the piano is 261.63 Hz, it is no surprise that we can hear it!
By now you’re probably wondering, given the title of this post: “Could I use my mobile phone as a particle accelerator??”
Particle accelerators use RF (radio frequency) waves to accelerate particles – similar to the ones that are used by your mobile phone. To give a particle some energy, you need a cavity – which is basically a hollow metal box.
When a wave of the right number of oscillations per second enters the cavity, it bounces back and forth within the cavity, with low loss. In physics we call this a standing wave. As more wave energy enters the cavity, it adds to the standing wave, creating a ‘resonance’.
What happens when we put a particle through the cavity? If we time it just right, the particle will always see a ‘peak’ of the wave and will gain a little bit of energy from it. If we didn’t time it right, the particle would lose energy to the wave and slow down. Fortunately, we’re very good at timing these things precisely!
An LHC RF cavity which works at 400 MHz. Photo courtesy of CERN.
The particle only gains a little bit of energy each time, so it’s useful if we have a circular accelerator where the particles go through the cavity again and again, gaining more energy each time. This is what happens in accelerators like the Diamond Light Source (using electrons) or ISIS (using protons), and even in the LHC. We can also use more than one cavity, the one in the picture has (I think) four cavities in one, and we can place them end-to-end. It’s a game of weighing up the cost of more cavities with how long your particles will take to accelerate.
So is it possible to just connect up a mobile phone to the cavity and accelerate particles? It would be great (and make my life as an accelerator physicist a lot easier!) but unfortunately it’s a question of power.
A mobile phone handset has a peak output power of about 2 Watts. The LHC cavities require a power of around 300 kW per cavity – so you would need the same power as 150,000 mobile phones!
So unfortunately, it looks like it isn’t going to happen any time soon. But in the meantime, I find it fascinating that the LHC and my mobile phone are, at least in some way, based on the same technology.

Friday, 5 November 2010

The end of an amazing journey

It’s drizzly outside and I have a headache but make no mistake; today is a very good day! Yesterday, for three hours I somehow managed to defend my thesis against the onslaught of questions from my examiners and emerge at the other end. OK so I emerged slightly shaken, mostly from my own nerves, but still alive. It wasn’t so bad, after all.

It would have been nice if there was a clear moment when you’re told “you’ve passed, it’s over”, but the official decision is the University’s, not the examiners, so instead you get the rather long mouthful of “we are convinced that you have fulfilled the requirements for the degree of Doctor of Philosophy and we will be making a positive recommendation that you take leave to supplicate for the degree.” It’s a big mouthful of words but for most purposes, it means the same thing.

I wasn’t quite prepared for the rush of emotion brought on by those slightly archaic but necessary words. It hadn’t dawned on me that I had moved 17,000 kilometers from home and spent three years working toward that moment. With hindsight I can see why it had that effect, but at the time the sudden feeling that I was going to burst into tears came as a bit of a shock!

The champagne followed, naturally, which is why today I find myself in a slightly headachy state. Despite that and the drizzle, I am really happy to have finally finished. I know many PhD students get to the end and struggle to say they enjoyed it but I really did. I’ve had some amazing opportunities, been to incredible places and met many of the top people in my field.

It’s been an amazing journey and I have so many people to thank for making it the unforgettable three years that it’s been. Here’s hoping that the next three will be just as good.