The Portable Cosmic Ray Detector

Free talks and demonstrations available to schools

Jointly funded by Public Understanding of Science Small Awards, PPARC, Swindon, UK and Department of Physics, University of Bristol, Bristol, UK.

Cosmic rays are fast-moving atomic nuclei that bombard the earth from outer space. The Portable Cosmic Ray Detector allows us to view cosmic rays from the comfort of our lecture theatre or class-room, without the need of climbing the Eiffel Tower, taking a hot air balloon ride, visiting one of the giant telescopes or travelling on a space craft. The detector reveals the presence of cosmic ray muons and electrons; it can also be used to view particles produced by a radioactive source.

Cosmic ray research commenced in 1910 with several interesting discoveries.

1910: Wulf carried his home-made electroscope to the top of the Eiffel Tower and observed that the rate of change of discharge was not as slow as expected. (It had been assumed that the radiation was emitted by the Earth and would therefore decrease at height).

1912: Victor Hess and two assistants flew in a balloon to an altitude of 16,000 ft and discovered evidence of a very penetrating radiation (cosmic rays) coming from outside our atmosphere.

1932: Robert Millikan carried out a series of tests on the intensity of cosmic rays at various altitudes in a Condor bomber plane.

1935: Explorer II, rubberized helium balloon ascended to 22,066 ft collecting cosmic ray data.

1940: A Beechcraft AD-17 biplane flown at 21,050 ft took cosmic rays data.

1950: A US Naval Research Lab Viking research rocket was fired to collect cosmic ray data.

1952-57: The "Rockoon" balloon-launched rocket carried out high latitude and high altitude cosmic ray research.

1959: Explorer VII was launched into an Earth orbit revealing information about cosmic rays near Earth.

1969: Apollo II astronauts deployed a cosmic ray experiment.

1972: Apollo 17 carried a lunar surface cosmic ray experiment.

1975: The Geostationary Orbiting Environmental Satellite was launched.

1975 - Present Day: Nearly every space craft launched carries cosmic ray experiments. The 2002 Nobel Prize was awarded in part for research into cosmic rays.

The detector is a hand-held, particle-tracking detector based on scintillating glass, fibre optic plate technology. It is housed in a light-tight box and is powered by a 9-volt battery.

The output screen of the image intensifier can be viewed directly by eye under low-level room light conditions or via video imaging with a CCD camera.

A Quick Time video clip of the display from the detector when placed in a high energy particle beam can be viewed here.

The portable real-time cosmic ray detectors are built by the Department of Physics and Quarknet Centre of the University of Notre Dame, Notre Dame, Indiana, USA.

To use the Cosmic Ray Detector:

The detector can be borrowed for Public Understanding of Science events. It is available for talks/demonstrations in schools, colleges and universities. There is no charge for using the detector. It is housed at the Department of Physics, University of Bristol. For further information please email phys-pp-outreach@bristol.ac.uk.

To invite a speaker to give a talk at your school or college:

Speakers from the Physics Department at the University of Bristol are able to visit schools and colleges and give a variety of talks. Follow the link to see what talks are available, the intended age of the audience and the parts of the physics syllabus they address.

For further information please email phys-pp-outreach@bristol.ac.uk.