CLOUD CHAMBER  Alex Robinson  Alex Leopardi  Jordan Bills

MOTIVATION, BACKGROUND, AND CONTEXT Shed some light on the topic of nuclear radiation Outreach Purposes

A cloud chamber is an easy way to visually demonstrate concepts related to radioactivity, specifically alpha particle decay

Current cloud chamber hinges on availability and use of dry ice

Improve upon this design by the use of thermoelectric tiles as a replacement for dry ice

Picture of our cloud chamber

THEORY Super saturated alcohol (90% isopropanol) is cooled to around

‐20°C in a chamber using a peltier device to form a cloud. A radioactive material is placed inside the chamber; as nuclear particles decay and fly through the cloud, the alcohol vapor immediately condenses where the particle passes forming visible vapor streamlines.

RESULTS (USING PELTIER DEVICE)

Cooling capability of the Peltier device largely depended on ability to dissipate heat from the back side of the device.

With proper heat sinks/pumps we were able to get the Peltier device (without chamber on top) to ‐27°C

Stacking Peltier devices only resulted in ‐18°C The coolest temperature we were able to achieve inside

the chamber was ‐10°C but only at the center which was still not cold enough.

RESULTS (ANALYZING STREAMLINES WITH CHAMBER ON DRY ICE) Used Uranium-238 for the radioactive material as opposed to

the originally proposed lantern mantle Streamlines started being visible at ‐15°C at the bottom of the

petri dish (chamber) Geiger counter gave a reading of 190 CPM (counts per minute) Recorded a 0:20 video of cloud chamber to analyze

streamlines, viewed in the slow motion setting the video was 2:44

Counted streamlines in 8s intervals, determined there were an average of 3.8 streamlines per second equaling about 228 CPM

CONCLUSION Unsuccessful in creating a cloud chamber useful for

outreach demonstration purposes using the peltier device

Ideas for future iterations Our counted estimate of CPM > Geiger counter CPM

reading possibly due to the Geiger counter only being able to detect decaying particles in a relatively small area

Gained knowledge about nuclear decay, heat transfer, redirection, and dissipation, as well as more technical hands-on skills

Thermal image of Peltier device heating at edges

REFERENCES Cameron Reinhart Anthony Butterfield