An international team of researchers in Japan is getting ready to power up a 50,000-ton neutrino detector by adding a single metal, which will turn it into the world’s first detector capable of analysing exploding stars beyond the immediate neighbourhood of the Milky Way.
Neutrinos are relics from supernovae, or exploding stars. They are so tiny and interact so weakly that every second, trillions of them manage to pass through human bodies without anyone noticing. Studying them can reveal details about how stars in the universe, like our sun, work.
The problem is that all supernova neutrinos that have been detected to-date have come from the immediate vicinity of our galaxy. No one knows whether neutrinos from older galaxies far outside ours act the same way as neutrinos close to Earth, or whether there is a completely new class of tiny particles yet to be discovered.
Experimental physicist Mark Vagins of the Kavli Institute for the Physics and Mathematics of the Universe and Ohio State University theorist John Beacom wanted to see if it were possible to improve Japan's largest neutrino detector, Super-Kamiokande. One of their ideas was to add the rare-earth metal gadolinium to the detector’s water tank, taking advantage of the gadolinium nuclei’s ability to capture neutrons.
If a neutron released from a neutrino interaction were nearby, it would be absorbed by the gadolinium, which would release the extra energy by creating a flash of light: a signal that could be detected by the equipment. But before any tests could be run, the two researchers needed to find out if their idea made scientific sense and predict what complications they might need to overcome.
First, water inside the detector would need to be transparent. Neutrinos interact with water, creating tiny flashes of light that are picked up by the photomultiplier tubes lining the walls of the tank. If gadolinium made the water murky, it would prevent the phototubes from detecting any light.
Second, the gadolinium needed to be uniformly spread within the tank so it could be close enough to a neutrino-water interaction to magnify its signal.
"These two criteria, uniformity and transparency, mean the gadolinium must be induced to dissolve," says Dr Vagins. "We've spent over ten years figuring out how to do it."
In July 2015, Dr Vagins announced at an international conference in Tokyo that he had developed the necessary technology and will now start plans to enrich Super-Kamiokande with gadolinium.
Gadolinium is a by-product of the extraction of other rare earth metals, some of which are used to produce the colours in flat-screen TVs. This makes gadolinium affordable so that Dr Vagins and his team will be able to purchase the 100 tons needed to help Super-Kamiokande detect neutrinos from distant supernovae.
Did you know?
Super-Kamiokande is a gigantic detector located one kilometre beneath Mount Ikenoyama, inside an old mining tunnel in Kamioka, central Japan. The pure water inside the giant 50,000-ton tank acts as a target for a range of particles being studied today including neutrinos, leftover particles from supernovae, resulting in a tiny light flash that is picked up by sensitive phototubes lining the walls. In 1987, Kamiokande, the original experiment in the same mine, recorded the first supernova neutrinos. The experiment was headed by University of Tokyo special university professor emeritus Masatoshi Koshiba, who was awarded a Nobel Prize in Physics in 2002. In 1998, Kamiokande and Super-Kamiokande proved neutrinos have mass, resulting in the 2015 Nobel Prize in Physics for Takaaki Kajita, who had been a graduate student of Dr Koshiba.
For further information contact:
Kavli Institute for the Physics and Mathematics of the Universe
Read the story in Asia Research News 2016
Motoko Kakubayashi | Research SEA
IceCube experiment finds Earth can block high-energy particles from nuclear reactions
24.11.2017 | Penn State
New proton record: Researchers measure magnetic moment with greatest possible precision
24.11.2017 | Johannes Gutenberg-Universität Mainz
High-precision measurement of the g-factor eleven times more precise than before / Results indicate a strong similarity between protons and antiprotons
The magnetic moment of an individual proton is inconceivably small, but can still be quantified. The basis for undertaking this measurement was laid over ten...
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
24.11.2017 | Physics and Astronomy
24.11.2017 | Health and Medicine
24.11.2017 | Earth Sciences