John Hill watched with eager anticipation as controllers ramped up the power systems driving SLAC’s X-ray laser in an attempt to achieve the record high energies needed to make his experiment a runaway success.
The Brookhaven National Laboratory scientist was the leader of a research team that had come from Illinois, Germany, Switzerland and England to use the Linac Coherent Light Source (LCLS), and this was their last day. They would get only one shot.
Gathered in SLAC’s Main Control Center with LCLS staff members, the team watched as blips of green appeared in a long sequence across a screen. Each represented a klystron working at full power to accelerate a beam of electrons, which would be converted to LCLS X-ray pulses. To reach the high X-ray energies they were aiming for, all of the 80 klystrons associated with LCLS would need to operate at near-peak levels.
In a few instances, the lights turned red. “The users asked, ‘Is it over?'” recalled LCLS staff scientist Marcin Sikorski. “No. They brought the klystrons back quickly, in a matter of minutes.”
With all systems go, the energy of the X-ray pulses soared to 11.2 kilo-electronvolts (keV) – a new record, about 35 percent higher than LCLS had originally been designed to reach – and stayed there for 24 hours nearly uninterrupted. It’s a performance the LCLS staff hopes to duplicate and even exceed, to the benefit of a wide range of future experiments.
Read more at: Phys.org