Bud Schultz's Neutrino Page

by Bud Schultz

This lesson was created as a part of the SMART website and is hosted by the Illinois Institute of Technology


Objective: To learn about neutrinos, how they were discovered and how they can possibly be used.


Where do they come from?

Neutrinos are are subatomic particles that are emitted during beta decay. This decay consists of a neutron that breaks into a proton, electron and a neutrino. The neutrino has no charge and until recently was thought to have no mass. They are almost impossible to detect due to this lack of charge and that they react with almost nothing at low energies. At high energies the neutrino is about as massive as an electron and interacts in a similar manor without the charge implications. Neutrinos are emitted naturally with typical solar reactions and are thought to also be emitted in the galactic center of most galaxies where it is believed that super-massive black holes are found. The solar neutrinos are energetic and can be used for astronomical purposes such as seeing a photo of the interior of the sun. See the related link Solar photo 1 or Solar photo 2 and answer the following questions.

Question 1

How many axes of symmetry do you see in the first solar photo?

a.) 1

b.) 2

c.) 4

d.) an infinite number

Question 2

How long these images of the sun take to make?

a.) Less than a second

b.) over a minute

c.) over an hour

d.) over a day

e.) over a month

How do we know neutrinos exist and how do we detect them?

There are two large scale programs currently dedicated to the study of neutrinos and their detection. They are the Super-Kamiokande (Super-K) and the Sudbury Neutrino Observatory (SNO) . Both of these programs utilize large tanks filled with heavy water  (here is a second reference site) which is the target area for neutrinos to interact with in our world.

Neutrinos are very prevalent in space, aka anywhere since they travel through almost anything without interacting. A tremendous number of them pass through you every second and do virtually no damage to you.  For this reason many people feel they may be the main constituent to dark matter.  Read the first two sections of Neutrinos as Dark Matter from E. White of UCLA 

E. White gives us an idea as to the vast amount of matter possible in the universe.  This would account for many of the inconsistencies that scientists see in the Amount of matter available vs. The observed motion, of galaxies.  We have not observed enough material to account for the observed motion of the galaxies we have studied and the neutrino can possibly account for this inconsistency.

So Astronomers are very interested in neutrinos for a few reasons.  They allow us to delve into objects that were unobservable previously and also they can account for the mass that appears to be necessary for the observed motion of the heavens.  Now if those darn MOND people would just go away.


Question 3

Why do we take photos of the sun using only neutrinos?

a.) they expose film better than photons.

b.) they move quicker than photons and can give a sharper image.

c.) they are coming from all layers of the sun simultaneously.

d.) the detectors are not able to pick up light and neutrinos without them interfering.

Question 4

How many neutrinos pass through your body on average every second?

a.) 1 x 103

b.) 1 x 106

c.) 1 x 109

d.) 1 x 1012

e.) 1 x 1015

Question 5

Why are neutrinos a likely candidate for dark matter?

a.) they react with most things and will expose film to look dark.

b.) they won't react with almost anything and will expose film so it looks dark.

c.) they react with most things and won't expose film so it looks dark.

d.) they won't react with almost anything and won't expose film so it looks dark.

e.) they have no mass, so we cant see them.

I hope you had some fun with this.  If your my student see me for a little EC.

Back to the SMART home page.