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Monday, 5 March 2012

"All science is either physics or stamp collecting." Ernest Rutherford

Okay, wrote this a while ago, like a month and have had all the busy since then, so I'm gonna post it now and the posts will continue from now as weekly (hopefully) supplements of my life. 

So, lets get down to some Physics!

I was never really planning this blog to go with the whole Physics side of things, but you know what?

Physics is cool. People like Physics. And those people shall be rewarded, with... well.. Physics!

Tomorrow, my Dissertation for my Masters is due in. Thus, slightly just for my own ease and slightly because it's cool, I'll let you all know what I did at Yale!

I think I'll put the dissertation up on some kind of filesharing if people want to learn more about it at the end, but for now, here is a brief history of Matt @ Yale.

I've been wondering for a good 2.4 seconds how far I should go back, in terms of Physics. I believe this will best suit people either doing Physics, or with an active interest in Physics, since you probably won't bother reading this if you have neither of these things. So I won't go right back to things like explaining what the nucleus is or anything like that, but I'll try and make sure you all understand me without a Physics degree.

Okay, first things first. MY BAD! I got caught up in the whole after dissertation being done thing that I completely neglected this blog entirely. So I'm here now, getting it done just before the presentation about this work tomorrow and then I shouldn't be doing Nuclear again, well maybe, possibly at some point...

So, my dissertation is titled Precise Measurements of lifetimes and deorientation in 92,94Zr using the g-plunger technique. Yeah, bit long isn't it? In effect it means we measured some stuff about some interesting nuclei really well. That's about it.

So, how did we do this? It starts with the simple effect of Doppler Shift. For those that don't know, this is the apparent shift in wavelength of waves due to their motion relative to the observer, in other words, like a car: Neeeeeeaaawwwwwwwhhhhhhh....
Basically the set-up excites a nucleus through coulomb (electromagnetic) interactions, from which it then flies a set distance to a stopper foil, where it becomes embedded.

This means that 2 things can happen;
1. The nucleus decays and emits a gamma-ray during flight, observed Doppler Shifted by the detectors
2. The nucleus decaus stopped in the foil, meaning an unshifted ray is observed

By increasing the flight distance, it will be more likely for the nucleus to decay during flight, which can then be plotted to obtain the lifetime of that state, in essence.

There are a whole load of corrections which have to be firstly applied to this lifetime, to account for the
  • Efficiency of the detectors
  • Lorentz (relativistic effects) 
  • Deorientation during flight of the magnetic moment. 
 Using this deorientation, a relative g-factor to a nearby nucleus can also be calculated, by comparing the rate of deorientation, which should be dependant on the magnetic moment of the state.

Most of this is what I actually did on my placement! That is the simple version of everything which I got done. Dissertation is done. Presentation is done. Paper is (nearly) done!

My presentation should be up on youtube soon, since they were recorded, including a small interview, brilliant! The presentation is actually much better than this explaination, I think, so I'll link to that as soon as it comes up!

Brilliant. Until next time!

Quick update, the youtube video with us talking has gone up, couple of snippets of me, but it's really terrible.

Paddy looks really sad in the still...

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