Two Slit's Cricket by Teachspin: The Instrument

Two Slit's Cricket

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Cricket turns signals emerging from the photomultiplier of our Two-Slit Interference, One Photon at a Time into audible individual clicks. In the single-photon mode of the two slit apparatus, photons emitted by a light bulb source are incident on the photomultiplier's photocathode, where they create photo-electron ejection events. These single photoelectrons are multiplied inside the photomultiplier to form a charge pulse, which in turn is amplified electronically and is used to fire an electronic discriminator. Each firing of the discriminator produces one TTL output pulse of about 400 µs duration. Ordinarily these pulses are directed to only to an electronic counter.

But the pulses recorded by the counter will also trigger the Cricket. Cricket's electronics stretch each 400 µs TTL pulse into a 5 ms long internal pulse and for a 5 ms duration Cricket emits a tone of fixed amplitude and frequency from its piezoelectric buzzer. The result is a short tone-burst, which sounds very similar to an old- fashioned Geiger counter, for every photon detection event. The sound is clearly audible for a whole classroom of listeners.

Learn about Two Slit Interference, One Photon at a Time.