Cloud Chamber
[Can detect: Alpha, Beta and Gamma]
- Figure above shows a simple form of cloud chamber, a device which enables the tracks of charged particles to be seen.
- The felt ring round the top of the chamber is soaked in alcohol. The bottom of the chamber is cooled by 'dry ice' (solid carbon dioxide) to around -80 °C.
- As the alcohol vapour spreads downward through the chamber, it is cooled beyond the point at which it would normally condense.
Alpha-particle tracks: |
Beta-particle tracks: |
Gamma-ray: |
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiPI2jWWJ50EnDoDms0QJxpRAMcwICMUB9h6ImOkBXZnjzE8KVjdc09bkYt-5-uniaXKB6lqTtPgZsjuUV1KngCSv-Snt8ilfW9wMmsNJSW3hRS1jBT1gmFCYug_9uhrKoFzKCgr7U9ECk/s200/Picture11.png) |
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgbUllZ3Eyp2NhloWHVTNhcD27czXU72wX-ujV5pKZJm2LqVznKAsB7QyXLTVAaGSVBHHhkX-1q-XxIt4fsccIPHj8JaAgFkTNZ4nbnyT47SzGFdxvXS2RuFPYhBx7QNG2ISf1IA9BF9sw/s200/Picture12.png) |
![](https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEisV6REe4X_2IzWOB4gQLJMn-Bx6kMxRk5eymTIsfCYCdUkKhb1Shcw-baCEYGb_dVyWVnjKdWBVlZ984GEs5EOkxP_obEmLB64qVhO0EJucfhs3WcaD4sN2IrEeLiUc39mtyZ79a0r_kM/s200/Picture13.png) |
Thick and straight, with the occasional deflection if an alpha particle collides with an air molecule. |
Thin and crooked. The particles cause much less ionization and, being light, are continually being pushed off; caused by air molecules nearby. |
Don't produce tracks as such. The tracks seen are those caused by electrons which have absorbed energy from photons and have escaped from atoms. |