Yesterday’s Grauniad blog post by Jon Butterworth about neutrino physics reminded me that I forgot to post about an important milestone in the development of the NOvA Experiment which involves several members of the Department of Physics and Astronomy in the School of Mathematical and Physical Sciences here at the University of Sussex. Here’s the University of Sussex’s press release on the subject, which came out a couple of weeks ago.
The NOvA experiment consists of two enormous particle detectors, one at the Fermi National Accelerator Laboratory “Fermilab” near Chicago and the other in Minnesota. The neutrinos are actually generated at Fermilab; the particle beam is then aimed at the detectors the, one near the source at Fermilab, and the other in Ash River, Minnesota, near the Canadian border. The particles, sent in their billions every couple of seconds, complete the 500-mile trip in less than three milliseconds.
The point is that the experiment has managed for the first time to actually detect neutrinos through the 500 miles of rock separating the two ends of the experiment. This is obviously just a first step, but it’s equally obviously a crucial one.
Colleagues from Sussex University are strongly involved in calibrating and fine-tuning the detector, which produces light when particles pass through it. Dr Abbey Waldron and PhD student Luke Vinton have developed a calibration procedure that uses known properties of muons to calibrate precise measurements of the neutrinos, which are less well understood. The detector sees 200,000 particle interactions a second, produced by cosmic rays bombarding the atmosphere, and scientists can’t record every single one. Sussex’s Dr Matthew Tamsett has developed a trigger algorithm that searches for events that look like neutrinos among the billions of other particle interactions.
Neutrino physics is an interesting subject to someone like me, who isn’t really a particle physicist. My impression of the field is that was fairly moribund until 1998 when the first measurement of atmospheric neutrino oscillations was announced. All of a sudden there was evidence that neutrinos can’t all be massless (as many of us had long assumed, at least as far as lecturing was concerned). Now the humble neutrino is the subject of intense experimental activity, not only in the USA and UK but all around the world in a way that would have been difficult to predict twenty years ago.
But then, as the physicist Niels Bohr famously observed, “Prediction is very difficult. Especially about the future.”Follow @telescoper