Spark Chamber

  • Our first prototype may have been small but it still made a big impact at Physics at Work, 2009.
  • An extra-terrestrial friend checking out the advanced Mark II technology at PhysicsFest, 2009.
  • With visitors and helpers at ScienceLive, The Royal Society Summer Science Exhibition, 2011.
  • Similar to a spark chamber, streamer chambers were capable of very good resolution. This stereoscopic image is UA5 data from the 1980s.
Spark Chamber Diagram

How a spark chamber works.

Spark Chamber MarkIII (Bruns)

The Mark III chamber in action.

A spark chamber is a stack of conducting plates separated by a gas gap. When an energetic ionising particle passes through the device, a control circuit applies a high voltage between each pair of neighbouring plates. The voltage generates a spark between each of the plates. The spark prefers to form at the spot where the particle passed through, due to the ionisation trail left by the particle. The path of the traversing particle is thus revealed by the array or line of sparks, which may be seen or photographed through the side of the device. The hey-day of the spark chamber as a research tool for detecting high energy cosmic rays came to an end in the 1960s when it was replaced by better techniques (drift chambers, bubble chambers, silicon detectors etc). Nevertheless, spark chambers are still designed for museums and used in education as they are an exciting, visually direct and simple way of demonstrating cosmic rays to an audience. Find out more...


Operational notes

Once installed, there is very little that needs to be done. The gas can be allowed to flow continuously at a low flow rate of about 10ml/min. Note that the bubbler doesn't usually bubble continuously at this flow rate but you should see some bubbles from time to time.

It is best to disable the high voltage when the chamber is unattended (e.g. overnight, weekends). The HV enable/disable switch can be found at the rear of the chamber at the bottom. Optionally, when the HV is disabled, the mains input to the chamber may also be switched on or off at the back and also at the wall socket. Even with the HV disabled but with the mains on you should see the green and amber LEDs flickering at the back. The amber LED should light every second or so when the electronics are working - it indicates the passage of a cosmic ray particle.

In the event of any emergency, switch off the the chamber (preferably as described above, but immediately at the wall socket or other circuit breaker if necessary). Close the main valve of the gas bottle.

Read the operation manual here (PDF).

Spark Chamber Calendar and Bookings

Future events highlighted in green.