QuarkNet2006
From MariachiWiki
Cloud chambers were replaced by Bubble chambers in the early 60’s. In June of 1959, C.L. Stong describes how amateurs could build a cloud chamber with magnetic field to study cosmic rays. His elaborate design allows for the detection of tracks and permitted the analysis of elementary particles. Today with advance of technology, especially materials and electronics, it is much easier and simpler to build cloud chambers with magnetic field and image tracks. Modern computer technology can be used to record and process cloud chamber images. Cloud chambers with magnetic field are an incredible teaching tool. From basic physics to pair production there is a lot of science to be explored!
During the workshop participants built a magnetometer to map out the magnetic field used to momentum analyze particles that penetrate the chamber's sensitive volume. The inexpensive magnetometer (really inexpensive!) can be used to map out other magnetic fields as well. Participants have also operated the chambers and developed an extensive list of ideas of how to use them in the classroom.
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Date, Location and Other Details
The Workshop took place at LIGASE from June 26 - 30 from 8:30-17:00 hrs. A follow up saturday workshop will take place in Fall/2006. Click HERE to download the calendar of events. This workshop was limited to 15 participants. First time QuarkNet participants can apply for graduate credits from Aurora University. Participants will receive a $375 stipend. For further information contact Helio Takai, at takai_at_bnl_dot_gov.
List of Participants
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The Uses of Cloud Chambers
Ideas on how to use a cloud chamber in the classroom setting
26 June 2006 (Monday)
Gaussmeter/Magnetometer Building and Calibration
To map the magnetic field in the cloud chamber we first built our own magnetometer. The magnetometer is an improvement on an earlier magnetometer built in PHY579. It uses an inexpensive Hall sensor manufactured by Allegro Microsystems. For this workshop we have included an inexpensive multimeter (price is too low to be quoted), and it is part of the system. As in the previous design we have calibrated the probe against a professional grade Hall probe. Each workshop participant build one magnetometer. Of course, as soon as we built the magnetometer, we had another brilliant idea for another design - we can't tell you here - but as soon as we have it working it will be posted in this wiki.
Here is Bill Leacock's procedure for building the second version of the magnetometer
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We have also used the bucket method to determine the polarity of the magnets for the cloud chamber. This technique to find the poles was developed by Tom and Jeremy Tomaszewski.... The method uses a floating bucket to align the magnet with earth's magnetic field. Even very large magnets such as the one we use floats easily as shown in the pictures.
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Other pictures
Pictures taken by Helio during the first day of the workshop.
- Happy - participants discussing probe calibration.
- Step by Step - The step by step probe calibration setup. Each step corresponds to a measured magnetic
field by a professional grade magnetometer.
- Tania Entwislte and Rebecca Grella adding the seal to the cloud chamber
- Chris Capone working on the "Capone Chamber of Horrors" under the watchful eyes of Cosmic Chris.
 Happy |
 Step by Step |
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27 June 2006 (Tuesday)
The Old Faithful
In the morning we used the old cloud chamber to demonstrate what kind of tracks one can expect to see. The old chamber is a large fish tank and it has three powerful magnets to bend particles. This chamber was first constructed by Tara Falcone in the summer of 2003. Since then it went through several changes and upgrades but it is basically the $10 fish tank. The major step in design was made in Spring of 2006 when magnetic field was added. Ken Tiu had very strong permanent magnets and they were added to the bottom plate by Bill Leacock and Adam Plana. The magnetic field is roughly 400 Gauss where most particles are detected.
The pictures show the preparations for the operation of cloud chambers, and people watching the chamber as it detects cosmic ray particles.
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Cloud Chamber Construction
If it is tuesday it must be chamber construction day! And so it started. An army of physics teachers with a very loose coordination building many, many chambers... In spite of the chaotic environment all chambers were built. Few parts were not available for everybody, but will be available before the summer end. The chamber desing follows the same desing as the The Old Faithful but uses a smaller fish tank (5.5 gallons) and one magnet only. We gave up on the idea of having alcohol containers inside the tank and use felt hanging from the top with Velcro. We call this arrangement the hammock (Invented by Tom Tomaszewski and seems to hold enough alcohol for a couple of hours. Some tanks were drilled so that more alcohol can be poured on top of the hammocks if required. The dry ice container is smaller and holds about 2 lbs of dry ice (determined experimentally).
Drilling glass is not for the faint of heart! If you want to do it, use a fresh bit, and go very slow!!!
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Bubbles
What to do with left over dry ice? Some suggests a dry ice bomb! Well, we didn't do that. So instead, we used the big box with dry ice and dropped few soap bubbles. Because soap bubbles are less dense than CO2, it floats in that environment. Pretty cool...
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28 June 2006 (Wednesday)
Chamber Field Mapping
To map the chamber magnetic field we used the magnetometer built on monday. Bill Leacock prepared plywood, spacers and 2 cm grid paper to facilitate mapping. To measure the field strength the probe is placed every 2 cm and values in Volts read. These values are input to excel spreadsheet and converted to Gauss using the calibration obtained monday. Most field distributions are uniform but some have bumps.
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29 June 2006 (Thursday)
World Record Day! 12 Magnetic Field Cloud Chambers Working at Once!
60 lbs of dry ice... that's what we needed to run 12 cloud chambers simultaneously. The hammock design works well, and with one soak it is possible to run the chamber for approximately 3 to 4 hours. Chambers that did not run initally was because there was not enough ice, not enough acohol or leaks in the base plate (i.e. screws were not too tight).
We have recorded a video, and taken a lot of pictures with tracks. Stay tuned for images...
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30 June 2006 (Friday)
It is a wrap!
The last day of QuarkNet this week! We took some time in the morning to work on the individual wiki pages and also to Brainstorm on Uses of Cloud Chambers in the classroom. The list is long and distinguished. We had a demonstration of videoconferencing with Joe Sundermier who at the time was in BNL. We had lunch at Jasmine's in the Wang Center and in the afternoon we discussed the MARIACHI experiment.
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 Last Minute Solder |
 A visitor from far |
 Relaxing |
Tracks
Here's few raw frames from the chamber built by Candice. The movie was made using a digital video camera (Canon model ZR200). To capture each frame we used iMovie (Mac OS). No processing is done to these pictures. It is easier to make videos and extract frames. Digital cameras offer higher resolution but it is harder to capture a single track using them.
- Overhead shot - Taken nearly straigth overhead shows one particle bending in the magnetic field
- Two tracks - This frame has two tracks also bending in the magnetic field.
- Big looper - a single track that almost makes an 180 degree turn.
- Heavy Ionization - Occasionaly very heavily ionization trails are seen. They are most likely protons.
 Overhead shot |
 Two tracks |
 Big looper |
 Heavy ionization |
Note for few details. Along the track you will see brighter spots and sometimes the brighter spots are tiny tracks. These are electrons that are scattered off their orbits leaving the atom ionized. The ionization density tells you what the particles might be. If you look carefully there are tracks with few bright spots to all bright spots. The all bright spots are very dense ionization - this information combined with the radius of curvature can tell you what particle you have seen. For example short tracks with high ionization and no curvature is an indication of a particle with low (e/m), for example a proton. Long tracks with low ionization are likely to be muons or pions (very rarely seen at sea level). Squigly tracks indicating lots of scattering, and medium ionization are electrons.
