Diffusion Cloud Chamber (15 cm diameter)

Diffusion Cloud Chamber (15 cm diameter)

SE-7943   - 

This version includes all the components of the Cloud Chamber and a coupon for the required Pb-210 Needle Source which is shipped to you via SpecTech™.

Diffusion Cloud Chamber (15 cm diameter) - No Source

Diffusion Cloud Chamber (15 cm diameter) - No Source

SE-7940   - 

This is is the same cloud chamber without the coupon for the Source Needle.

Also Available:

Pb-210 Source Needle

Pb-210 Source Needle

SE-7945   - 

A replacement PB-210 Needle Source.  It is USNRC License Exempt (US only).  Outside the US, consult local laws and regulations.  Purchased sources are "Non-Cancellable" and "Non-Refundable".  See the bottom of this page for details.


The Diffusion Cloud Chamber is used to view high energy alpha particles, lower energy beta particles, and electrons produced by gamma rays interacting with gas molecules. The Chamber allows for the viewing of cosmic rays without the need for dry ice or external illumination.

About the Pb-210 Needle Source:

A needle source is used to generate a point source of radiation inside cloud chambers for demonstrating alpha and beta radiation tracks. 

The source is constructed by depositing a small quantity of radioactive isotope onto the eye of a standard sewing needle which is mounted on a test tube stopper for insertion into the cloud chamber. The needle and stopper are placed into a test tube for protection during shipping and storage.

Special Features

  • Uses ice water instead of dry ice
  • Water circulation pump
  • Built-in high voltage (~800V) power supply for clearing the chamber of unwanted ions
  • Powered by 12V DC power adapter
  • Built-in LED lamps for illuminating the particle trails


  Diffusion Cloud Chamber (15 cm diameter)
Diffusion Cloud Chamber (15 cm diameter) - No Source
Pb-210 Source Needle
Cloud Chamber
12 VDC Power Adapter (6 A)
Water Circulation Pump
2 Rubber Hoses
Extraction Pipette
Source Holder and Stopper
High Voltage Connection Cable
SpecTech™ Coupon for Pb-210 Source Needle

How It Works

The bottom of the chamber is cooled by circulating ice water through the base and further cooling it to -35 C with a Peltier device. Alcohol placed in the chamber wicks up the inside chamber lining where it evaporates in the warmer region of the chamber and diffuses downward. The alcohol vapor is then cooled near the chamber bottom and becomes super saturated. 

As energetic alpha and beta particles from a radioactive source pass through the alcohol vapor, the vapor condenses, forming droplets that appear as tracks in the strong chamber cross-lighting.


Buying Guide

Replacement Parts
Pb-210 Source Needle
Product Name Part Number Price Qty. Select
Pb-210 Source Needle   SE-7945

Source Disclaimer

PASCO Radioactive Source Disclaimer - Please review prior to purchase

Before purchasing PASCO radioactive sources:

Local, national, and international regulations may restrict the purchase, storage, transport, use or disposal of radioactive sources.  Please  consult your local regulations to ensure your compliancebefore you purchase radioactive sources.

  • PASCO advertised sources are direct shipped to customers from Spectrum Techniques (  Please review their "Terms and Conditions" page before purchasing.
  • Once shipped, purchased sources are "Non-Cancellable" and "Non-Returnable". Radioactive sources cannot be returned under any circumstances including "End of  Life" disposal.


  • PASCO generally advertised sources are USNRC License Exempt (US only). 
  • International exempt sources (per the International Atomic Energy Agency) are  available for international customers or by request.
Time: 8/9/2016 11:11:47 PM