An amusing project from NIST for using a LEGO “Watt balance” — the device used in the recently updated definition of the kilogram — to measure Planck’s constant h. I’ll be firing this one up at home, for sure!
Following on from the 2015 Nobel Prize, the Sudbury Neutrino Observatory has just been awarded the 2016 Breakthrough Prize:
The Physics prize is shared amongst multiple collaborations, including SNO, Super-K, K2K, KamLAND, and Daya Bay.
(As you all know, I did my graduate work on SNO. I also worked for a year on Daya Bay shortly before coming to Otterbein.)
Neutrinos continue their glorious ascendency.
My experiment is seeing first data! Hooray! Neutrinos in liquid argon, everyone!
Look at all that gorgeous structure. Straight lines are muons or pions. It looks like there’s a cosmic ray going down through the middle of the neutrino event, and there’s also what looks like a nice gamma ray (or pi-0) coming out the bottom. Lovely!
See more event pics here: http://www-microboone.fnal.gov/first-neutrinos/
From the press release:
Today the MicroBooNE collaboration announced that it has seen its first neutrinos in the experiment’s newly built detector.
“It’s nine years since we proposed, designed, built, assembled and commissioned this experiment,” said Bonnie Fleming, MicroBooNE co-spokesperson and a professor of physics at Yale University. “That kind of investment makes seeing first neutrinos incredible.”
After months of hard work and improvements by the Fermilab Booster team, on Oct. 15, the Fermilab accelerator complex began delivering protons, which are used to make neutrinos, to one of the laboratory’s newest neutrino experiments, MicroBooNE. After the beam was turned on, scientists analyzed the data recorded by MicroBooNE’s particle detector to find evidence of its first neutrino interactions.
“This was a big team effort,” said Anne Schukraft, Fermilab postdoc working on MicroBooNE. “More than 100 people have been working very hard to make this happen. It’s exciting to see the first neutrinos.”
MicroBooNE’s detector is a liquid-argon time projection chamber. It resembles a silo lying on its side, but instead of grain, it’s filled with 170 tons of liquid argon.
Liquid argon is 40 percent denser than water, and hence neutrinos are more likely to interact with it. When an accelerator-born neutrino hits the nucleus of an argon atom in the detector, its collision creates a spray of subatomic particle debris. Tracking these particles allows scientists to reveal the type and properties of the neutrino that produced them.
Neutrinos have recently received quite a bit of media attention. The 2015 Nobel Prize in physics was awarded for neutrino oscillations, a phenomenon that is of great importance to the field of elementary particle physics. Intense activity is under way worldwide to capture neutrinos and examine their behavior of transforming from one type into another.
MicroBooNE is an example of a new liquid-argon detector being developed to further probe this phenomenon while reconstructing the particle tracks emerging from neutrino collisions as finely detailed three-dimensional images. Its findings will be relevant for the forthcoming Deep Underground Neutrino Experiment, known as DUNE, which plans to examine neutrino transitions over longer distances and a much broader energy range. Scientists are also using MicroBooNE as an R&D platform for the large DUNE liquid-argon detectors.
“Future neutrino experiments will use this technology,” said Sam Zeller, Fermilab physicist and MicroBooNE co-spokesperson. “We’re learning a lot from this detector. It’s important not just for us, but for the entire neutrino community.”
In August, MicroBooNE saw its first cosmic ray events, recording the tracks of cosmic ray muons. The recent neutrino sighting brings MicroBooNE researchers much closer to one of their scientific goals, determining whether the excess of low-energy events observed in a previous Fermilab experiment was the footprint of a sterile neutrino or a new type of background.
Before they can do that, however, MicroBooNE will have to collect data for several years.
During this time, MicroBooNE will also be the first liquid-argon detector to measure neutrino interactions from a beam of such low energy. At less than 800 MeV (megaelectronvolts), this beam produces the lowest-energy neutrinos yet to be observed with a liquid-argon detector.
MicroBooNE is part of Fermilab’s Short-Baseline Neutrino program, and scientists will eventually add two more detectors (ICARUS and the Short-Baseline Near Detector) to its neutrino beamline.
A new experiment carried out in the Netherlands has confirmed the “spooky action at a distance” that is a central feature of quantum mechanics. There have been several such confirmations, going back to the early 1980s, but this is is the first one that simultaneously closes all the loopholes that might arise. It may therefore be the final blow to the idea — championed by Einstein and Bell, among others — that quantum mechanics is incomplete and there might be local “hidden variables.”
The preprint version of the paper is available here.
Last week Dr. Reinhard and his students detected ultracold rubidium atoms in a magneto-optical trap for the first time. The atoms, seen below with an infrared sensitive camera, have a temperature of about 100 micro Kelvin, or about a million times colder than room temperature. For reference, the surface of the sun is only about 20 times hotter than room temperature.
The MicroBooNE detector is now full of liquid argon!
Nine tanker trucks put 34,000 gallons of liquid argon into the detector, finishing July 9. The fill was carefully watched by everyone at Fermilab, with Dr. Tagg’s silly but useful webpage. (Warning: soundtrack.)
Interesting and inspiring article on the (history and) future of physics by Frank Wilczek.
OP2: Operation Physics, a crash course in physics for middle school science teachers, is underway now at Otterbein. The course features many hands-on activities and the teachers receive loads of gear for teaching science. The program is supported by a grant from the Ohio Board of Regents, and is in its 6th year at Otterbein.
A student riding in a train looks up and sees Einstein sitting next to him. Excited, he asks, “Excuse me, professor. Does Boston stop at this train?”