The biggest science facility to be built in the UK for 30 years has marked its first major milestone.
The Diamond machine has produced its first "synchrotron" light beam, which will allow experiments to get underway.
Diamond is described as a series of "super microscopes" that will probe the structure of matter down to the scale of atoms and molecules.
Experiments at the Oxfordshire facility could lead to breakthroughs in physics, medicine and environmental protection.
Located at a science campus near Didcot, the £300m-plus Diamond Light Source is housed in a vast doughnut-shaped building covering an area the size of five football pitches.
The core of the machine is an enormous ring that runs for 562m. Electrons are fired into this ring and accelerated in a vacuum to velocities approaching light-speed.
As the electrons are steered around the ring by huge electromagnets, they lose energy in the form of synchrotron radiation - exceptionally intense beams of X-ray, ultraviolet, and infrared light - also known as synchrotron light.
This light is channelled into areas of the facility known as beamlines. These research stations are equipped with state-of-the-art instrumentation that allows scientists to probe deep into the basic structure of matter.
HOW DIAMOND WILL WORK
Electrons fired into straight accelerator, or linac
Boosted in small synchrotron and injected into storage ring
Magnets in large ring bend and focus electrons accelerated to near light-speeds
Energy lost emerges down beamlines as highly focused light at X-ray wavelengths
Researchers hope these investigations will lead to scientific breakthroughs.
Diamond will eventually host up to 40 beamlines around the synchrotron ring.
Synchrotron light has been used to help improve foods, cosmetics, drugs and surgical tools. It is used in medical imaging, the detection of toxic substances in the environment, forensics and monitoring stresses in complex engineering structures such as aircraft wings.
Commenting on the first synchrotron light beam at Diamond, the facility's head of accelerator physics, Riccardo Bartolini, said he was "very encouraged" by the early data.
The project is funded by the UK government and the Wellcome Trust.