Tommy MacDonald's 207 Woodworking Community • View topic

rwyoung · **Posted:** Fri Dec 23, 11 2:57 pm

So, I've been busy away from the office and definitely away from the workshop.

As part of my job I'm currently at the South Pole working on a large, multi-university physics project to build a detector for neutrinos from deep space. It will use the ice sheet as a radio telescope of sorts.

Attachment:

majorleagueww.JPG [ 286.59 KiB | Viewed 285 times ]

Today (for me, I'm on New Zealand time) is 12/24. Merry Christmas all.

Attachment:

_MG_2193.JPG [ 254.03 KiB | Viewed 285 times ]

p.s. we ate the last elf that showed up here...

farms100 · **Posted:** Fri Dec 23, 11 4:17 pm

that is awesome!

its been so long since high school physics that my kids are in honors Physics at high school.

The detector sounds pretty interesting, why did they choose the south pole?

****Edited to add****
oh the ice sheet (face slap)

Do you guys do any classroom video conferences?

rwyoung · **Posted:** Fri Dec 23, 11 6:41 pm

farms100 wrote:

that is awesome!

its been so long since high school physics that my kids are in honors Physics at high school.

The detector sounds pretty interesting, why did they choose the south pole?

****Edited to add****
oh the ice sheet (face slap)

Do you guys do any classroom video conferences?

1) The Earth acts as a "filter" to help block out the lower energy neutrinos.
2) The South Pole (during winter) is relatively "quiet" in the RF sense (detectors work in the frequency band of about 100MHz to 1GHz).
3) The ice sheet has very good radio transmission properties so when a neutreno does interact with the ice, producing a meuon and the resulting RF pattern it can be more easily detected.

And there are no video conferences from the South Pole due to limited internet connectivity via satellite. They use the GEOS and TDRS satellites, both of which are considered obsolete. It just so happens that they wobble by for a few hours every day.

The project name is "ARA" - Askaryan Radio Array. We are working on a prototype for what will become a detector spread out over 100 square kilometers. The current large detector is nicknamed "IceCube" and occupies a cubic kilometer. Google can find their home page at the University of Wisconsin (lead university in the collaboration).

farms100 · **Posted:** Sat Dec 24, 11 1:37 am

rwyoung wrote:

3) The ice sheet has very good radio transmission properties so when a neutrino does interact with the ice, producing a meuon and the resulting RF pattern it can be more easily detected.
.

probably a stupid question, but I'll ask anyways.

I thought most radio telescopes had some sort of parabolic reception dish?

rwyoung · **Posted:** Sat Dec 24, 11 2:05 pm

farms100 wrote:

rwyoung wrote:

3) The ice sheet has very good radio transmission properties so when a neutrino does interact with the ice, producing a meuon and the resulting RF pattern it can be more easily detected.
.

probably a stupid question, but I'll ask anyways.

I thought most radio telescopes had some sort of parabolic reception dish?

If you were looking directly for the RF (i.e. "Contact" with Jodie Foster), then yes. But in this case, they are looking for neutrenos, a sub-atomic particle. They aren't directly detectable due to their lack of general interaction. But if they collide, there is a shower of other particles created and a resulting RF burst. The RF travels outward in the shape of a cone (also light and sound is created). It is the RF cone they detect, triangulate and then project backwards to the source of the particle.

Neutrenos are produced in the sun, the Earth's atmosphere, supernova, the big bang, even in the small amount of radioactive decay occurring continuously in your body. But these guys want to see the really high energy ones, ones made in supernova, the big bang and other unknown phenomena. Because they are such high energy to begin with and are not affected by magnetic fields, they travel in straight lines and act like pointers back to their source.

farms100 · **Posted:** Sat Dec 24, 11 8:16 pm

so you wont actually detect the actual particle, your looking for the after effect of a collision.

my next silly question is

How will you know its a neutrino, not some other particles having a reaction?

rwyoung · **Posted:** Sat Dec 24, 11 8:46 pm

Given current knowledge, there are no other particles that have energies of similar magnitude or create a similar particle shower during collisions.

FLWoodRat · **Posted:** Sat Dec 24, 11 10:12 pm

RW,

Neutrinos, aye. What about their counterpart, the Anti-Neutrino? Will you detector array be able to identify them as well?

My understanding of Neutrinos is from the much lower energy ones associated with Beta minus (Anti-neutrinos) and Positron (Neutrino) radioactive decay and some higher energy particles associated with accelerators. I dont think any of them will compare to their cosmic cousins. Given the chance, I love to sit down with you RW and discuss them.

Bruce.

Who is online