Clara, the Compact Linear Accelerator for Research and Applications, is an ultra-bright electron beam test facility at STFC's Daresbury Laboratory, built to trial advanced free electron laser schemes and other accelerator physics concepts. Using three 4-metre radiofrequency cavities and a network of 77 electromagnets along a 60-metre beamline, it had reached an energy of 250 million electron volts and was expected to open to outside researchers in 2026.

The mothballing turns a facility designed to keep UK accelerator physics at the international frontier into a symbol of the STFC funding row, one now being examined in parallel by both the Commons and Lords select committees responsible for scrutinising UK Science spending.

Common Questions

What is the Clara facility at Daresbury?

Clara is the Compact Linear Accelerator for Research and Applications, an ultra-bright electron beam test facility at STFC's Daresbury Laboratory used to trial advanced accelerator and free electron laser techniques.Source: event

Why was the Clara facility mothballed?

UKRI confirmed on 9 July 2026 that STFC would cut national laboratory funding by 58% over four years, and mothballing Clara was part of that reduction.Source: event

How powerful is the Clara accelerator?

Clara had reached an energy of 250 million electron volts (MeV) using three 4-metre radiofrequency cavities and 77 electromagnets along a 60-metre beamline.

Which committee questioned UKRI over Clara's funding cut?

The House of Lords Science and Technology Committee took oral evidence from UKRI chief executive Sir Ian Chapman on 14 July 2026 on the agency's funding approach.Source: event

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