Inside the "brain" of the BaBar detector
23 September 1998
When the new PEP-II collider at the Stanford Linear Accelerator Laboratory (SLAC) in California starts operating in spring 1999, its electron and anti-electron (positron) beams will cross every 4 billionths of a second at the heart of detector called BaBar. It is not feasible to record all the data from the detector at this high rate, so instead specialised electronics must quickly "decide" if a collision is interesting enough for its data to be stored for further analysis. This system is known as the "trigger", and the image here shows a close-up of just one of the prototype trigger processing boards - in a sense the "brain" - of the BaBar detector. This particular board takes signals that show how much energy has been deposited in each of the 240 sections of the BaBar calorimeter - the energy-measuring layer of the detector. The trigger processor boards group together the energy measured in these sections and look for characteristic energy deposits left behind by the particles created in the decay of B mesons. (These are particles containing b quarks, one of the heaviest of the basic building blocks of matter.) The boards are being designed and developed by a team from. Bristol University, Imperial College (London), Royal Holloway (London) and the Rutherford Appleton Laboratory.
Credit: PPARC Press Office
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