If I tell you that there are
billions of particles passing through your body every second, what kind of particle
do you think they would be? The answer is neutrinos. These nearly massless and uncharged
particles travel at a speed closes to light. Because they can only interact
through weak nuclear force, matters are virtually transparent to them. Geoneutrinos
are electron antineutrinos, who are produced through beta-minus decay of
radionuclides inside the Earth:
Figure
1. Beta-minus decay process (McDonough et al.)
They can travel through the Earth
unimpededly from their origins, and carry integrated information about the
abundances of the radioactive sources, which will provide insights of the power
drives mantle convection, plate tectonics and geo-dynamo. So, how do we catch
these ghost-like messengers? For decades, geologists and physicists are working
side by side to solve this problem. In 2005, the KamLAND team first reported
the detection of geoneutrino (Araki et al. 2005).
Currently, there are five detectors
of neutrinos, which are KamLAND (Japan), Borexino (Italy), SNO+ (Canada), JUNO
and Jinping (both in China). ( McDonough et al. 2014) Geoneutrinos are detected by these giant underground
scintillation detectors via inverse beta decay mechanism (IBD). IBD process
involves an electron antineutrino enters detector, and interacts with a
hydrogen atom (a free proton) in the hydrocarbon scintillator, producing a
positron and a neutron:
Figure
2. Inverse beta decay process
This reaction requires the incoming
geoneutrinos carry at least 1.806 MeV energies to initiate the process. There
are only four isotopes that can emit geoneutrinos with sufficient energies to
trigger the IBD detection inside our detectors, which are 228Ac and 212Bi
in the 232Th decay chain and 234Pa and 214Bi
in the 238U decay chain.
As IBD activated, there will be two
flashes of light occurs inside the liquid scintillation detector: the prompt flash
is from the positron (product of IBD) and electron annihilation; and the second
flash comes from the neutron (product of IBD) captured by a proton producing
deuterium and generating 2.2 MeV of light. These two flashes are highly
synchronized (only 200 microseconds away) and only accessible to geoneutrinos,
which effectively eliminates most backgrounds. (Dye et al., 2012)
Figure
3. Structure inside detector (Chen et al., 2014)
Geoneutrino study is expecting a
new era of detection ability since a new deterctor JUNO, which is about twenty
times larger than KamLAND, will come online. With more data available, maybe in
the coming decades we can better constrain the abundance of the heat producing
elements like U and Th in the Earth.
This is a good first effort, but you lost me with many technical and scientific terms. We should work to get your grandmother to understand the importance of measuring these particles.
ReplyDeleteLots of scientific words that go over the head of anyone who isn't familiar with geoneutrinos. What is the difference between a neutrino and geoneutrino? How do geoneutrinos provide insights to tectonics and mantle convection?
ReplyDeleteWay to steal my comment, Jack.
DeleteLook at the post time bro, you copy-cat. Also, it's definitely not 5:30am...
DeleteThe term "neutrino" evolved into "geoneutrino". We can all make the connection, but it might be helpful for a general audience to explain the distinction.
ReplyDeleteSlow down you rate of delivery and increase your emphasis to make sure everyone can understand what you are saying. You do not give the audience time to understand the importance of statements. Where are these detectors, what are they made of, and what do they cost? Your English is excellent, so if you can just slow down you will be much more understandable.
ReplyDeleteI'd also suggest to narrow the focus of your talk. I think the reason that you feel the need to use so many technical terms is that your topic is complex.
ReplyDeleteYou started off the presentation with a lot of scientific terms that a majority of people aren't familiar with. You caught yourself using these terms in the second figure, but you should define everything you say i.e., MeV, positron, solar neutrino.
ReplyDeleteTry to use more common units. I also agree with the previous comments regarding the use of jargon. I liked the way you asked the audience questions and made the talk more engaging.
ReplyDeleteIt is a vey good talk. The concepts of geoneutrinos and how to detect them is well explained. I think you may want to add some more background introduction about how to use geoneutrino to study Earth interior. It will be helpful for general audience to see the big pictures.
ReplyDeleteI might suggest a picture of the neutrino capture devices. I liked talking about a big dark room where you have to look carefully for small flashes of light. Rather than a diagram, perhaps a visual will be more compelling? Something like this: http://www.wired.com/images_blogs/wiredscience/2012/03/lsnd.jpg
ReplyDeleteCool picture! I will definitly use it in my next presentation. Thanks!
DeleteThere is more information here than is needed. Also, try to talk slower. But otherwise very interesting topic!
ReplyDeleteWhy is this important for the general public to understand? Maybe start out with the big picture of why geoneutrinos are useful (but avoid terms like mantle convection and tectonics unless you plan on defining them). I personally like the connection between neutrino detection and nuclear weapons -it's a hot topic that the general public cares a lot about. Overall, nice job -you gave an excellent explanation of how the detectors work (although it was very scientific).
ReplyDeleteOverall, I found the talk to be very engaging, but the article a little less so. During the the talk you used to many scientific terms, but I enjoyed it and you kept my attention by engaging the audience, using humor and giving the most exciting explanation of what a geoneutrino that I have heard yet. That being said, I still don't fully understand it. I think if you take out most of the scientific terms and bring the humor from your talk into your article, it will be much better. Also, I liked your example of the geoneutrino passing through your body, are there other everyday examples of these concepts (how bright are the flashes of light compared to a desk lamp, or a shooting star, something like that).
ReplyDeleteThank you very much for making such heartful comments. I will adjust accordingly:)
DeleteFirst, you say geoneutrinos in your first paragraph are "who", they should be "what". Second, as others have stated, you go very much in depth to the topic. Its obvious you know the material, but perhaps you are overestimating your audience. Perhaps you should think of it like this: most people know OF radiation, but understand virtually nothing about it. Now imagine trying to relay what neutrino is to these people. That is the mindset you need to be writing to I think.
ReplyDeleteI think your post is fun to read and I liked the enthusiasm in your presentation. I think it might be useful to spend some more words describing neutrinos, geoneutrinos, beta-decay in your opening paragraph and/or integrating the images into your writing.
ReplyDelete