Sante Fe for a day

It's that part of the year when we make our second visits to our students on their MPhys Research Year placement.  I have two students I'm responsible for making a visit to -- one based in Tennessee and another in Indiana.  Where better to combine meeting both of them in one place than at the American Physical Society nuclear physics meeting in Sante Fe, New Mexico?

It's a part of the US I haven't visited before, and it's quite something -- huge open blue skies and breathtaking landscape.  The city itself is also rather pretty, with most of the houses built in adobe (or faux-adobe, really, but still rather distinctive).  There's a lot of public artwork in the city, and the picture attached shows one of our placement students, Abdellatif, standing in front of some fish statues poking out of the shingle.

Both of these placements are in nuclear physics -- one on developing algorithms for pulse shape analysis to help pinpoint where reactions take place in radiation detectors, and the other on improving theoretical calculations of neutron capture cross sections for stellar nucleosynthesis.  Both are getting on well, and have got a lot out of their research year.  Before too long, they will be back at Surrey to take their final semester of courses, and then on to the next thing.  I will back at Surrey on Monday!

A Week in Kyoto

I've been spending this week at the Yukawa Institute of Theoretical Physics at the University of Kyoto in Japan as part of a long-term (running over many weeks) workshop on theoretical nuclear physics. 

I'm here for just one week of it (this week, obv.). It's been a proper workshop -- with actual discussion,  and I've got lots of good ideas from the discussion and some plans for immediate collaborations with others, so it's been worthwhile from a physics point of view.

I also like coming to Japan.  It's a nice country to visit.  Not always easy for people such as me who haven't learnt Japanese, but that's not quite an obstacle enough in the big cities.  Of course, I should learn Japanese if I ever become a more regular visitor.

By chance, the particular week I am here includes the Jidai festival, which happens on 22nd Oct every year.  It celebrates the history of Japan, and happens in Kyoto because it is was the capital city of Japan for ~1000 years before that role passed to Tokyo in the nineteenth century.  The picture in this post shows a snap I took from the procession.  I could in principle be out now watching more of it, and the firework sounds are pretty loud in my hotel room, but I'm calling this bed-time.  

Plastic electronics

I had a nice time this evening watching and listening to Radu Sporea talking about plastic electronics (= built on a plastic substrate).  I work on rather abstract theoretical stuff, but I enjoy very much learning about physics research that is more directly aimed at creating new technologies.  Radu's talk highlighted electronic devices that can be created on flexible plastic sheets.  Perhaps the most obvious application is to mobile phone screens which can be flexible without breaking.  I'm fortunate in not having ever cracked my mobile phone screen, but it was only earlier today that I sat on a train opposite someone with a cracked glass screen.  

Open Access Week

I saw from an email from my University that it's Open Access Week next week, and that they are running a number of events to celebrate 10 years of Open Access being supported at the University.  I guess that's good, but I wonder if they'd like to know that the first paper I published on arriving at Surrey was submitted to the arXiv in 2000, a bit more than 10 years ago, and has thus been open access for all that time.

I would perhaps go along to one of the events and gently make this point, but I will be in Kyoto all next week.  Exciting!

Bulgaria!

Greetings from Sofia!  I'm attending a workshop, which goes by the name SDANCA, which stands for Shapes and Dynamics of Atomic Nuclei: Contemporary Aspects.  I don't know if the acronym is supposed to convey any particular meaning in Bulgarian, but googling while on a Bulgarian IP address brings up a freestyle wrestler called Stanka Zlateva (I guess the Cyrillic станка can be transliterated just as well to Sdanka).  

We've had day one, and I was fortunate enough to be given a talk in the first session.  I always like to get my talk out of the way and enjoy the rest of the workshop without thinking about my own talk.  It's been a nice event so far -- it's really working as a workshop, with some proper discussion, unlike some attempted  workshops which are just conferences with talks and a short time for questions for those few speakers who do not overrun horribly.  

My favourite talk so far was from a speaker from Heidelberg who talked about possibilities for direct laser-nucleus interactions.  It's a topic I've blogged about before, and one that is likely to lead to the first 'nuclear optics' applications.  Her talk was not very sanguine about the hopes for immediate applications, but one promising thing is the potential use of the first excited state in Th-229 (at a mere 8 eV -- less than the atomic ionisation potential of hydrogen) as a nuclear clock for precise standards of time.

I took the picture, above, last night during the registration period.  The three people most in the foreground were the speakers in the first session today: (L-R) Peter Ring, Yang Sun and George Lalazissis.  In the background is Nikolay Minkov, who chaired that first session, as well as being the prime mover in organising the workshop.

From COMEX5 in Krakow

I'm at a conference in Krakow, Poland.  The conference is called COMEX5.  My other half said it sounded like a comic convention.  It's not, but it does indeed share a name with a convention which took place in Singapore a couple of weeks ago.

The COMEX title is an abbreviation of "Collective Motion in Exotic Nuclei."  Despite this being the series's fifth outing, it is really quite a venerable conference series, it being a re-branding of the Giant Resonance conference.  Giant resonances are the main topic of the conference.  They are vibrational states which are very collective in nature, meaning that they feature the action of all nucleons in the nucleus.  Their observation dates back to the mid 1930s when at least the first hint was seen (by Bothe and Gentner in Heidelberg).

I'm giving a talk here on Thursday about using time-dependent methods to describe these resonances, and what is shows about the underlying structure of the nuclei.  I also, of course, take part in the organised events during the conference, such as the reception in Krakow's beautiful Collegium Maius, as pictured.

Suggestions from PRL

Last month, I commented about the high proportion of articles in the nuclear physics section of Physical Review Letters that are in the sub-field of relativistic heavy ion collisions (RHIC) and how they form the preponderance of articles promoted by the editors to appear on the journal front page.   In the last month, the trend has continued, and only RHIC papers have been highlighted.  So, let me highlight here a paper which was published last month, and has been picked up by a few news websites:

The paper is called "Direct measurement of the mass difference of ¹⁶³Ho and ¹⁶³Dy solves the Q-value puzzle for the neutrino mass determination."  The physics motivation behind the work is that the nuclear reaction:

¹⁶³Ho + e^– → ¹⁶³Dy + ν_e

can be used as a model-independnt (i.e. not relying on assumptions about the structure of the nucleus that may not be correct) mans of determining the mass of the electron neutrino -- something that is not pinned-down at all well.  The mass of the neutrino is known to be extremely small, but not zero.  By observing the above reaction, and using conservation of energy, one can work out the energy balance (the "Q-value" of the title) from the observed particles, and deduce the energy carried off by the (unobserved) neutrino, and hence its mass.  To be able to do this, the masses of the two nuclear isotopes in the equation: Holmium–163 and Dysprosium–163 must be known to very high accuracy.  Actually -- it is only the difference between the two masses that needs to be known, and there is disagreement in the published data what this difference is, to a level that swamps the tiny neutrino mass.

The experimenters here used a Penning trap to store ions of each of the isotopes.  For a given particle of mass m and charge q moving in a trap with magnetic field B, the particle will move in a circle with frequency f=qB/(2πm).  Measuring the frequency allows a value of the mass to be determined.  They put the two different ions in the same trap at the same time, but in separate bunches, reducing systematic effects to do with e.g. variations in the magnetic field.  They concluded that their value for the mass difference is at variance with the "accepted" value (that published in the Atomic Mass Evalution) by more than 7 times the size of their error bar.  Thus, the error in determining the neutrino mass should be able to be reduced in future experiments looking at the reaction above.