Siena College Cloud Chamber 2025

What exactly is a Cloud Chamber? How does it work? Am I really seeing particles?

A cloud chamber is a small particle detector, but you aren't seeing the particle itself. You are seeing the track left by the particle.

The "chamber" that we create is made to reach extremely cold temperatures using devices that absorb heat such as the cooling fan and peltiers. The heat transfer is made more efficient using thermal paste. Then by adding the alcohol to the chamois cloth, we see alcohol vapor. As the particle travels through the air, the air becomes ionized, so the alcohol condenses around that air. This is how we see the track of the particle.

The Power Supply

1. Plywood (At least 16 x 11 inches)
2. https://www.lowes.com/pd/1-4-in-Common-P...
3. 500 W Power Supply
4. https://www.amazon.com/EVGA-WHITE-Warranty-Supply-...
5. UpHere D6SEC CPU Air Cooler
6. 
   
7. Washers
8. Spare Wires
9. 12709 peltier
10. https://www.amazon.com/SMAKN%C2%AE-TEC1-12709-Ther...
11. 12710 peltier
12. https://www.amazon.com/TEC1-12710-Thermoelectric-C...
13. Arctic Silver 5 Thermal Paste 7g (Alternative: Arctic MX-5 Thermal Compound)
14. https://www.amazon.com/Arctic-Silver-AS5-3-5G-Ther...
15. 100 mm Petri Dish
16. https://www.amazon.com/Disposable-Petri-Dish-35mm-...
17. Chamois Cloth
18. https://www.amazon.com/AmazonBasics-Drying-Chamois-...
19. 24 Pin Colored Adapter
20. https://www.amazon.com/ZYAMY-Female-Computer-Power-Adapter/dp/B081RPV4N6
21. LED String Lights
22. https://www.amazon.com/Flexible-Waterproof-Holiday-Outdoor-Decoration/dp/B075R4X1XL
23. LED light connectors
24. https://www.amazon.com/Flexible-Waterproof-Holiday-Outdoor-Decoration/dp/B075R4X1XL
25. Handles
26. https://www.homedepot.com/p/Everbilt-4-7-8-in-Blac...
27. #4-40 x 1" Oval Head Phillips Screws
28. https://www.homedepot.com/p/4-40-x-1-in-Combo-Round-H...
29. Cable Clamp
30. https://www.amazon.com/Cable-Lokman-Stainless-Rubb...
31. Lever Nuts
32. https://a.co/d/boEqJWP
33. Black Spray Paint
34. https://www.walmart.com/ip/Black-Rust-Oleum-Americ...
35. Optional Edging:
36. Rubber: https://www.lowes.com/pd/KidKusion-Corn...
37. Wood:
38. #6-32 x 1" Flat Head Phillips Screws
39. #8 x 3/4" Flat Phillips
40. Electrical Tape
41. https://www.lowes.com/pd/Scotch-700-Electrical-Tap...
42. Isopropyl Alcohol
43. https://www.amazon.com/Amazon-Brand-Isopropyl-Al...
44. Super Glue (Optional)
45. Thoriated Tungsten Rod
46. https://shop.tungsten.com/tig-welding-electrodes-10-pack/?sku=40400-02602B&utm_term=&[…]b2WgkX52bOpYRxTePFukw720cRTy-PD9P9rvUhKHJAL-Ls0aAuFIEALw_wcB
47. Adjustable Feet
48. https://www.homedepot.com/p/Everbilt-1-1-16-in-Threaded-Gl
49. Here is the link to the STL files of the 3D prints you'll need to build your cloud chamber, enjoy!!
50. https://github.com/mattbellis/turn-key-cloud-chamber/tree/master/version_2025_Matta

The first step is to create the base of the cloud chamber. Cut a piece of wood that is 16" x 11". This base can be slightly larger, but it is not recommended as the size listed keeps the cloud chamber portable but large enough for all the parts.

You can use any kind of wood, but 1/2" thick plywood is recommended. Once the wood is cut, feel free to add any stain, paint, or aesthetic changes to the wood you like!!!

How to cut fitted edges: https://youtube.com/shorts/_VOCZlvugyg?feature=shared

For safe portability, it can be very helpful to add edging. Grab four pieces of edging that are larger than the sides of your board. To cut your edges for any sized board, use the technique in the video and the images attached for the best fit! You need to make a line on your first piece of edging based on the width of your second piece of edging. It is harder to do the same thing with edging that is already cut, so use a ruler to help you as shown in the photos. Then draw a diagonal line as shown in the photo based on the direction your edging needs to fit onto the board. Once your four pieces are cut, clamp down the edging and use a saw to cut down to the desired size. Then use wood glue on the inside and clamp the edges to the board to dry for an hour (or multiple if needed).

To attach the adjustable feet to the cloud chamber, measure an inch away horizontally and vertically at each corner of the board. Then mark those points. The label on the adjustable feet should include the kind of drill bit needed to secure the feet into the board. Make sure to drill a hole that is not too big to make sure the feet are not loose. One there are holes in the board, tap the glide socket into the board (you may need to force the glide socket into the board) Then use a hammer to slide it in all the way and screw the feet into the glide socket. Make sure all four feet are screwed in the same amount, so the board stands straight. Adjust the feet as needed for an even surface.

To attach the 3D parts into the base, first place them on the wood and mark the places where the screws would be. Then you can use a drill or drill press with a 1/4" drill bit and drill holes at each marked spot.

Take the #8 x 3/4 inch wood screws and screw in the 3D printed holders for the D6SEC air cooler and the 500 W power supply in the board.

Optional: Grab the black handles and place one on each side of the board. Mark where the screws would be, drill in the holes, and then screw the handles onto the board.

To secure the power supply onto the board, slide the power supply into the holder with the pin connectors facing the part of the holder that has a gap. Use the picture for more reference. Take the 3D printed lid and position it so that the triangles on the lid align with the extrusions on the mount. Once they are aligned you can slide the lid (direction away from you) onto the mount until it clicks. It is helpful to hold the arms of the power supply holder, and use your thumb to push the lid on.

Take the bottom of the petri dish, and cover the edges with masking tape. Lay it on a piece of newspaper with the bottom facing upwards, and spray paint the back of the dish black. Let it dry and then peel the masking tape off. For certain radioactive sources that extend past the width of the petri dish, it is necessary to add a hole into the side of the petri dish. To do this we use a soldering iron and melt through the plastic of a petri dish. Make sure to start with a small hole and slowly increase the diameter!

Use the bottom of the petri dish to cut a circle of chamois cloth (it should be just under 3 and 1/2 inches in diameter). Then you'll need to draw another circle inside. Use something circular to trace a smaller circle that is about 2 and half inches in diameter (Ex. Roll of tape). Then fold the circle of chamois cloth in half and cut a small opening where your inner line is. Now unfold the circle and cut along the line you drew.

Place the ring onto the lid of the petri dish to make sure it fits correctly, and then super glue the ring onto the dish. Make sure not to use too much so that the glue doesn't overflow onto the middle of the dish. The leftover glue could obstruct the view of the particles later on when your cloud chamber is done!

When you take out the D6SEC fan, first take the cardboard sheet out from between the two fans.

In the D6SEC box there will be the fan and a bag of extra parts and screws. On the fan there are two spring screws, use the technique shown in the video above to take them out. Find the straight metal bracket (Part A in the manual). In the straight metal part, there is a screw coming out of the middle pointing downwards. Put the screw through the holes in the metal parts coming out under the CPU. Then screw the hollow screws (the ones you just took out of the spring) onto the screws coming out of the bottom to secure part A onto the cooling fan. You may have to use small pliers to tighten them. Reference the pictures above for clarification.

Put the #6-32 x 3/4 through the holes you see on the bottom of the fan when the fan is facing you. Very carefully place the fan into the 3D printed mount with the screws coming out of the slits in the mount, then secure the fan into the mount by screwing the wing nuts onto the screws. With the power supply and the fan mounted your cloud chamber should look like the photo above so far.

Find the 24 pin adapter on the power supply and the 24 pin connector. Connect the 24 pin adapter on the power supply and the 24 pin connector together. Now the 24 pin adapter is connected, take the following wires:

5 Black wires (ground)

2 Yellow Wires (12 V)

1 Red wire (5 V)

1 Green Wire (Power Supply ON)

Make sure to cut off the plastic part of the 24 - pin connector that isn't attached to the power supply. Take masking tape, loop a piece around each wire to create a label for them, use the picture above as a reference. Do not cut the extra wires until the cloud chamber is completely assembled just in case you make a mistake and need to use different wires.

It doesn't matter which black or yellow wires you use, they carry the same voltage.

Grab the CPU wires attached to the power supply. Orient the wire so that the tab is on the bottom when you look at the openings for the wires. The diagram shows that the upper two wires are ground, and the bottom two are 12 V. Pick one of these wires to be yellow wire 3. Use the photo for reference.

WARNING!: It's really important to do this part correctly, otherwise the power supply will not turn on, or you could brick the power supply. Strip the ends of Black wire 2 and Green Wire 1. Solder the ends of Black wire 2 and Green wire 1 together. Wrap this connection with electrical tape.

If you've never soldered wires together, not to worry! Use this link for an example.

https://youtube.com/shorts/2N6uXyUPfgA?feature=shared

How To Solder Wires:

Before soldering your wires, twist the ends of the wires together as shown in the photo. Then make sure they are set up using the clips on helping hands (yellow stand for soldering). Make sure the sponge on the stand of the soldering iron is damp, and make sure to heat up the soldering iron to approximately 800 degrees Celsius. Once the power supply shows that the soldering iron is finished heating up, hold the solder up to the connection of the wires and the soldering iron, and melt the solder onto the connection. Make sure the solder covers the exposed wire completely . Once you are done wrap this connection with electrical tape.

You can check to see if you have done this correctly by plugging in the power supply and turning it on. Make sure no exposed wires are touching !!!!

If the fans turn on, you have correctly completed this step and may move on! If the fan doesn't turn on make sure no exposed wires are touching.

Occasionally if the power supply doesn't turn on and you make sure no wires are touching, but it still doesn't work, unplug and then plug back in the 24- pin connector. We aren't sure why, but it seems to serve as a kind of reset for the power supply. :)

Find Black Wire 1 and Yellow Wire 1, and two spare, thinner wires. Strip the two thin wires 1/2 of an inch on one end and 1 inch on the other. To use the lever nut connectors to connect the spare wires to the labeled ones, pull up the orange tab on one end, put the stripped part of the wire inside and push the orange tab down until the wire is secure in the connector. Do the same with the other wires on the other end. Plug the extended Black Wire 1 into the far left slot on the adaptor port connected to the D6SEC fan, then plug Yellow Wire 1 into the slot directly next to Black Wire 1 (middle left).

To proceed to the next step, make sure the cooling fan turns on!!!!!!

It is important to know how well the peltier can transfer heat, and if it is not working properly, it can be difficult to change and try new peltiers in an assembled cloud chamber.

To test the peltiers, you will need a power supply, two wires, two lever nut connectors, ice, a paper plate and cup, and an aluminium block. Place the ice into the paper plate with a very little amount of water. The ice water should not fill up the plate. Place the block of aluminum in the water, the top of the aluminum should be exposed. If it isn't pour some water out of the plate. Use the extra wires you grabbed to connect the power supply to the positive and negative slots. Use the lever nuts to connect the positive wire to the red wire of the peltier and the negative connected to the black wire. Place the peltier on the aluminum block. Use the infrared thermometer to take the temperature of the peltier as you alter the voltage, make sure not to exceed 12 V for the 12709 peltier, and 5 V for the 12710 peltier. During this process make sure the ice is not melting enough that the water is covering the aluminum block, if so pour some of the water out into the cup. A working peltier should reach negative values as you get closer to the voltage.

We use the aluminum block to make sure we don't burn out the Peltier while testing it.

WARNING!: In this step you are instructed to use thermal paste, which can greatly affect how well your cloud chamber works. Make sure to evenly distribute a thin layer. Too little thermal paste will not provide enough cooling, too much and it can become insulating.

It is recommended is to apply a thin layer such that if you lightly scrape the paste, you'd be able to see the peltier itself. Reference the video for more instruction.

Take your peltiers (strip each wire half an inch if needed). Position the 710 Peltier so that the black wire is on the left and red is on the right. The wires of the peltier should be facing you. Using the Lever nut connectors connect the black wire to Black Wire 3, and the red wire to Yellow Wire 2.

With the black wire on the left and the red wire on the right, apply a thin, even layer of thermal paste onto the back of the 710 peltier and use a credit card like surface to spread it. Make sure there are no bumps or chunks in the paste, this is imperative to how well it works. Firmly press the peltier onto the D6SEC fan.

Plug in your power supply with no wires touching, if the top of the peltier is cold, you are successful! If not, try to flip the peltier over and try again.

Take the 709 Peltier, positioned with the black wire on the left and red on the right. Connect the red wire from the peltier and red wire 1. Connect the Black wire and Black wire 4.

Apply a thin layer to the top of the 710 Peltier and press the 709 on top of it with the red wire on the right and the black wire on the left. Plug in and turn on the power supply. If the top is cold, you have completed this step successfully!

A Peltier is a small device containing semiconductors transferring heat from one side to the other. The thermal paste is made of conductive materials, improving the connection between the Peltier, fan, and petri dish, allowing heat transfer to occur more efficiently.

Position the LED Holder so that the two slits coming out of the square are aligned with the wires of the stacked peltiers. The wires should be facing you. Use the #6-32 x 1 in screws, #6 washers, and nuts to secure the LED Holder into the brackets you attached onto the D6SEC fan earlier. Use the pictures for reference.

Foam Cutting Technique: https://youtu.be/lmnCYfHl4e4?si=lr3nFRUbo9v8UpsO

Measure the gap between the peltier and the inner square wall of the LED Holder. It should be a little less than 0.25 inches. Using the technique shown in the video above, cut three pieces of foam.

Tip: Cut a piece slightly larger than what you measured, so that you can shave down the foam piece to the perfect size little by little if needed. It is important that the foam pieces are not loose at all.

Carefully push the foam between the holder and the peltiers until the holder, peltiers, and foam are level.

Take the LED Strip lights and cut them to 16" or at a point that is relatively that size where it is instructed for you to cut.

Slide the end of the LED strip lights into the connector. Make sure the metal arms in the connector are completely on top of the copper connections in the strip lights. Tightly twist and bend the ends of Black wire 5 and Yellow wire 3. Use small pliers to carefully pull up the metal pins of the LED connector. Slide Black wire 5 under the negative connection's metal pin, and use the wire stripper to push down the pin onto the wire. Do the same to connect Yellow wire 3 to the positive connection.

Alternative:

Solder black wire 5 to the negative connection of the LED and yellow wire 3 to the positive connection of LED strip. To make this easier, use the solder to make small droplets on top of the LED strip at the connection point. Then press the wires into the droplet and cover them with more solder.

Once the wires are connected to the LEDs, wrap the connection in electrical tape.

To make sure the connection is secure, turn on the cloud chamber and see if the lights turn on.

Put a more generous, double the amount you put before, but still even layer of thermal paste on top of the 709 Peltier and press the black part of the petri dish to the top of the Peltier. Apply pressure to the petri dish overnight using the 3D printed puck. Place the puck inside the petri dish and put a textbook over it. Leave it overnight.

Once the weight is left overnight, remove the books and the puck, and put your radioactive source inside the petri dish. Take the lid of the petri dish and 0.5mL of isopropyl alcohol and evenly spread it across the chamois cloth using a pipette. Then put the lid back onto the petri dish, put the LED cover on top of the LED Holder and turn on your cloud chamber! Wait a little bit, and you should start seeing mist and then particle tracks!!!!

Make sure if you lift the petri dish off of the Peltier, you scrape the excess thermal paste off of the dish and the peltier, and even out the thermal paste before putting the petri dish back on.

Congratulations!