A 33-ton portion of the DIRC—the Detection of Internally Reflected Cherenkov light detector from the BaBar experiment—was recently moved from Building 620 to temporarily storage in Building 720 on SLAC National Accelerator Laboratory grounds.
Earlier this month, SLAC National Accelerator Laboratory moved a portion of the BaBar detector across their site. Its next stop could be Italy.
The job of the DIRC detector was to keep the kaons and the pions straight. It identified these products of B meson decay by analyzing that eerie blue light called Cherenkov radiation, emitted in this case by the charged products zooming through specially-fabricated blocks of quartz. The bars acted like giant optical fibers that trapped the blue light inside, bouncing it from wall to wall toward the array of 10752 photomultiplier tubes waiting to catch it.
Whether the DIRC will perform that duty once again is not known. It's available should SuperB, the Italian B meson detection project, decide to use it but the Italians have also expressed interest in parts from PEP-II, the accelerator for the BaBar experiment.
Regardless of its final destination, DIRC had to go.
"We've had to move the DIRC— and many other components—out of 620 to give us the space we need to dismantle the main steel support structure," said Stuart Metcalfe, BaBar Engineering Manager. "The next detector to be evicted will be the Barrel Calorimeter."
It was a move short in distance but long in planning and preparation. In fact, the move was scheduled for December of last year but the movers met with uncooperative weather, said Metcalfe. "We had to wait for a lot of planets to align," he said. "Today was the day."
