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Fundamental Researchstudied without regard to practical applications
Practical science Vs. Fundamental science
Is Fundamental science impractical?
Particle Astrophysics
Particle Physics
T
• There are many particles
• We are built out of only 3
• Other particles, like neutrinos, are created in particle accelerators or in space.
protons neutrons electrons
Cosmic Gall A Poem by John Updike (1932-2009)
NEUTRINOS, they are very small. They have no charge and have no mass * And do not interact at all. ** The earth is just a silly ball To them, through which they simply pass, Like dustmaids down a drafty hall Or photons through a sheet of glass. They snub the most exquisite gas, Ignore the most substantial wall, Cold shoulder steel and sounding brass, Insult the stallion in his stall, And scorning barriers of class, Infiltrate you and me! Like tall and painless guillotines, they fall Down through our heads into the grass. At night, they enter at Nepal and pierce the lover and his lass From underneath the bed-you call It wonderful; I call it crass.
- Telephone Poles and Other Poems, John Updike, Knopf, 1960
* They actually do have a very very very small mass
** Neutrinos do interact – but it is a super rare interaction
Neutrinos are very Rare particles False: We know that neutrinos are created in the sun and in the atmosphere. Every second thousands of neutrinos go through our body. In IceCube we look for energetic neutrinos from outer space. These are rare.
NeutrinosAre very small
Have (almost) no mass
And rarely interact at all
If we want to see
And interact with our detector
This must arrive
to our detector
must emit .
Traditional astronomy uses photons (light particles) as messengersA Telescope
(visible light, or X-ray or gamma-ray)
Sometimes 1” of matter is enough to stop a photon
True: Cover your eyes
?I need a different
messenger
Traditional astronomy uses photons (light particles) as messengers
Space is not empty.
A Telescope(visible light, or X-ray or gamma-ray)
To stop a neutrino we need 10 miles of matter
False: We will need much more matter to stop a neutrino
To make sure we stop every neutrino we would need 10 light years of lead. This is 1 million times the distance to the Sun full with heavy dense material
In IceCube we use Neutrinos to do astronomyNeutrino detector
Hey, Wait a minute:If those “neutrinos”
rarely interact,they will also “rarely”
interact with our detector
AVERYBIG
DETECTOR
How to detect a neutrino
Sonic Boom(Shock caused by moving faster than the speed of sound)
Cherenkov effect - “Optic” Boom(when a charged particle passes through matter at a speed greater than the speed of light in matter)
If a neutrino interacts in our detector, it produces a super energetic charged particle that moves super fast
What happens when things move fast??
Requirements from a neutrino detector rarely interact .
large detectors
Light measurement Dark Transparent
CostCheap material
Where to put it?
• IceCube will be made of 80 strings deployed in holes 1.5 miles deep (!)
• The bottom 0.6 miles of each string is instrumented with 60 super sensitive detectors.
“eyes”
• A cubic kilometer array of light detectors will look for this weak light
1.5
mile
0.6
mile
1.5
mile
0.6
mile
• IceCube will be made of 80 strings deployed in holes 1.5 miles deep (!)
• The bottom 0.6 miles of each string is instrumented with 60 super sensitive detectors.
“eyes”
• A cubic kilometer array of light detectors will look for this weak light
The eye in the iceDOM
Digital Optical Module
IceCube
South Pole
Dome
New Station
road to work
Ski-Runway (
road to home)
IceCube – where are we?