Underlying Subtleties

Since the topic of science in the media has come up somewhat often recently, I thought it would be interesting if I could shed a bit of light on a way which is perhaps better for science to be talked about in front of and for the public.

The inspiration for this came in a conversation between myself and a fellow MPhys student Matt Large about our projects. Something we hadn’t realised was that the superficial differences in the science of our projects belie a subtle underlying similarity to their utility. I shall leave it up to the reader to decide upon the relevance of each project (hint; mine is better). First; a little background on each project;

(Matt here!) My project centres on the measurement of Temperature. I work primarily on computer models of the equipment used to calibrate thermometers at National Measurement Institutes (NMIs) such as NPL. The thermometers in question aren’t your ‘garden variety’ Mercury or Alcohol thermometers, but rather Platinum Resistance Thermometers (PRTs). These work on the principle that electrical resistance changes with temperature; if you know the relationship between the two quantities (called a ‘reference function’) and your thermometer has been calibrated (i.e. it’s resistance has been measured at known Thermodynamic temperatures) then you can reliably measure knowing that your results will be accurate and precise. However, because of the way these reference thermometers are calibrated, there is a limit on the precision NMIs can obtain. This limit has a knock-on effect on all other measurements further down the ‘calibration chain’.

(Steve’s back!) My project, on the other hand, revolves around a kind of extremely sensitive light detector known as SPADs (Single Photon Avalanche Diodes, for those interested). In principle, SPADs have the capability to detect the smallest amount of light that can exist – a single photon. A SPAD is essentially a diode which is designed to break down when hit by a photon – this produces a big spike of voltage at the output, which is how you tell that there was a photon there. This happens to be a very new technology (most of the work is but a handful of years old), and so much of the experimental work in the field is time consuming and difficult to analyse. The work that I do focuses around developing the experimental methods so that they are both more accurate and easier to perform; then using these methods to produce the most accurate results we can for the SPADs which RAL is developing. The process of producing numbers which tell you which SPADs are good is known in the field as characterisation.

One of the key things here is that what I do is by majority practical (characterizing chips, making circuits, messing around with voltages, lining things up) whereas Matt’s is largely [pardon the pun] computing based (building computer models of the equipment, pressing buttons, thinking very hard). When you just look at the jobs we do – or the scientific fields we work in – our work seems completely different.

While pointing things like this out might seem like a trivial matter, it’s important to the next part of this post – let’s continue a little. Everything about our placements seems rather disparate – from our working environments to the organizations surrounding us; I work largely in a messy lab with a beat up old Windows XP desktop, whereas Matt has a brand new high-end simu-machine in an office. STFC is directly Government funded and is entirely focused on applications-based research; NPL is known worldwide as a bastion of excellent academic research, with both Government and Commercial funding.

So, with all that disparity in mind – how can we dare to say that these projects are the same? Well, firstly we’ll qualify the statement with the fact that we’re looking only at a subset of the work each of us does; the work that (if each of us is lucky) might be published later on. In a sense, that’s what really matters anyway.

The underlying similarity of the two projects is based in the subtleties of reasons for carrying out the research in the first place; there’s more to science than a title. Not only does the actual content matter here, but the history (and current state) of the fields of research, the politics of the different groups competing in the research area.

(Matt’s back) For me, it might be an interesting theoretical project but for the department as a whole it’s part of an ongoing effort to define how temperature measurements should properly be made. Temperature is probably the most measured physical quantity since almost everything in nature is affected by it; this means the measurement (and ultimately control) of Temperature is of fundamental importance in modern society. PRTs (as mentioned earlier) are used by National Laboratories to disseminate the International Temperature Scale of 1990 (ITS-90); by handing these (rather expensive!) calibrated thermometers to equipment manufacturers (where they are used to calibrate other thermometers) all temperature measurement can be traced directly back to ITS-90.  This assures us that all our measurements are still linked to the International System of Units (SI). This ‘traceability’ is fundamental to the science of measurement, or Metrology, and also to the wider Scientific community.

(Steve again) For me, my project is an effort to clear up the standards in a new sub-discipline. Our small team has had some trouble recently talking to other groups and communicating about experimental methods – there aren’t any standard tests yet; nobody has laid out a good way of making the tests both identical and reliable. We want to combine a theoretical understanding of how SPADs work, with industry standard data analysis to define a good way of setting the standard for how to make some of these measurements. Doing this means that not only can everyone make their own measurements more accurate (which is a good thing, since when you’re detecting single photons a small inaccuracy can change your results by quite a way!). More importantly, it will give separate groups a reliable method of comparing their SPADs to see which is best. That will lead to a more clear understanding of the field, and thence to better improvements for less money (which is good for everybody).

Despite the fact that the terminology is so different, both projects can currently be summed up in extremely similar ways; each project is attempting to persuade scientists in the field of measurement making that there is a better standard on which to work. By improving the standards, end applications can make more accurate measurements. Better things can be done more efficiently; this brings important developments out sooner and also at a lower cost. Ten years from now, perhaps some of the most important advances in medicine, engineering or travel could be influenced by our current projects.

And there’s the point – two completely different projects both have the same kind of motivation and the same kind of potential impact. Despite their differences, the subtleties to each project underline how interconnected science and the real world are, along with how interconnected different disciplines are within science itself.

For me, this demonstrates in particular the peculiar state that has defined science for a long time now; the majority of research is both fundamentally similar and wildly different – simultaneously abstract and fundamentally important (although in vastly different ways). Once you get past the jargon and the conventions, each piece of research has very similar goals. This underlines the elegance of science as a discipline; the details are different, but the overall structure is pleasantly regular.

Then again, the devil’s in the details – and that’s why science just keeps on going.


About stoove

A physicist, researcher, and gamesman. Likes to think about the mathematics and mechanics behind all sorts of different things, and writing up the thoughts for you to read. A competent programmer, enjoys public speaking and mechanical keyboards. Has opinions which might even change from time to time.
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2 Responses to Underlying Subtleties

  1. Nannie says:

    Hmm it looks like your site ate my first comment (it
    was extremely long) so I guess I’ll just sum it up what I wrote and say, I’m thoroughly enjoying
    your blog. I too am an aspiring blog writer but I’m still new to everything. Do you have any suggestions for beginner blog writers? I’d definitely appreciate it.

    • stoove says:

      Hi there, and thanks for the compliment! =] I’m sorry that something went wrong with your comment, I never saw it in the in-tray so I assume something bugged out on the WordPress side of things. Anyway, I think there is only one important thing to know as a beginner – write what you know, and do it often.

      For me, that means my topics are usually about science or my experiences as a student. You can also define for yourself what “often” means. You can take it to be “one post exactly every Mon/Weds/Fri” or you can aim for a post a week (like I do) and work around that.

      What I’m saying is find what’s comfortable for you and stick to it as much as possible. Chances are, if you can show consistent interest in your topic then other people will too 🙂

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