ATF linac test beam
On the evening of 26 May 2011, KEK scientists and engineers confirmed that a test beam successfully steered through the linac during the commissioning test of the Accelerator Test Facility (ATF).
“It went relatively smoothly, reached the end of linac in a half-hour or so,” said Nobuhiro Terunuma of KEK, Japan, the new spokesperson for the ATF international collaboration.
Following the successful injector commissioning test conducted a day earlier, “we had a beam to the entrance of the beam transportation line,” said Terunuma. The beam energy was roughly 1.3 gigaelectronvolts (GeV), the same as before the March 2011 earthquake.
ATF is a unique test facility for producing and controlling the ultra-low emittance beams that are required for linear colliders. For the ILC, the thinner the beam – or lower the emittance – the more particle collisions occur in the detectors. To produce electron beams that will have a similar quality as those of the ILC, the ATF damping ring squeezes the beam down to make it extremely thin – to the nanometre level.
“But we are not measuring the emittance yet,” said Terunuma. “Our priority is to proceed with hardware checks and to see if we can inject the beam to the ring.”
Another priority is beam alignment.
“Now we are working on aligning magnets, one by one, at the beam transportation line. Most of magnets are still waiting for the checkout,” said Sakae Araki, a KEK engineer in charge of magnet alignment. There is an array of magnets at the beam transportation line, and engineers are making precise alignments on them to prepare for the continued checkout using a test beam through the damping ring.
Most of the work on the beamline equipment is carried out during daytime, followed by test beam operations in the evening. “We hope to see a beam in the damping ring soon,” Terunuma said.
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