Accelerators

Particle accelerators employ electromagnetic fields to increase the kinetic energy of charged particles for applications spanning fundamental research, medicine and industry. Conventional radio-frequency (RF) accelerators use resonant cavities to impart energy over metre-scale distances, with gradients now approaching hundreds of megavolts per metre through cryogenic and surface-treatment advances. Dielectric laser accelerators exploit nanostructured photonic elements driven by ultrafast lasers to achieve gigavolt-per-metre fields in chip-scale devices. Plasma wakefield accelerators harness intense laser or particle beams to excite collective oscillations in ionised gas, yielding gradients of several gigavolts per metre over centimetres. Crystal channeling techniques guide particles along atomic planes, enabling compact steering, collimation and spin manipulation in high-energy beams. Recent developments integrate advanced materials, machine-learning-optimised conditioning and novel drive wavelengths to shrink facility size while boosting energy, efficiency and beam quality for next-generation accelerators.

Research from Nature Portfolio

Direct measurement of the optical near-field inside a nanophotonic accelerator has been achieved by coupling photon-induced nearfield electron microscopy with three-dimensional simulations. The technique uncovered fabrication-related field distortions, guiding the optimisation of grating geometries for enhanced acceleration efficiency.

Fused-silica dielectric laser gratings driven to record internal fields of 1.8 GV m–1 at 9 GV m–1 incident strength exhibit self-phase modulation that detunes the accelerating mode. Compensation via tailored free-space optics restores synchrony, enabling single-stage energy gains in the megaelectronvolt range.

A chirped spatio-temporal laser pulse applied to a single-stage dielectric accelerator has synchronised sub-relativistic electrons up to sub-MeV energies. Dispersion-controlled spatial chirp provides precise temporal and spatial matching of the accelerating field, suggesting portable MeV-scale sources.

Research from all publishers

Cryogenic X-band copper cavities cooled to 45 K have reached accelerating gradients of 250 MV m–1 with breakdown rates below 2 × 10–4 per pulse m–1. Reduced thermal stress and defect mobility at low temperature support extreme fields, informing compact high-gradient linac modules.

Computational and experimental studies of 400 GeV protons traversing bent silicon crystals mapped ionisation-loss spectra versus incidence angle. Non-monotonic loss behaviours and dechanneling effects highlight optimal alignment conditions for crystal-based beam halo control.

Dielectric laser accelerators driven by long-wave infrared lasers near 10 µm demonstrate broader channel apertures, higher charge transport and reduced divergence. Early tests and simulations indicate gigavolt-per-metre gradients with relaxed nanofabrication tolerances for scalable photonic accelerators.

Accelerators publication trend

The graph below shows the total number of articles in accelerators across all publications each year (not limited to Nature Index journals).

Technical terms

Accelerating gradient: The energy gain imparted to charged particles per unit length of an accelerating structure (MV/m).

Dielectric laser accelerator (DLA): A device that uses laser-driven electromagnetic fields in microfabricated dielectric materials to accelerate particles.

Beamstrahlung: High-energy photon emission induced by the interaction of opposing particle beams in a collider.

Wakefield acceleration: A technique in which a driving laser or particle beam excites a plasma wave whose fields trap and accelerate particles.

Dechanneling: The process by which particles leave a crystal channel due to scattering, reducing steering or collimation performance.

References

1. High gradient experiments with X-band cryogenic copper accelerating cavities. Physical Review Accelerators and Beams (2018).
2. Imaging the field inside nanophotonic accelerators. Nature Communications (2023).
3. High-field nonlinear optical response and phase control in a dielectric laser accelerator. Communications Physics (2018).
4. Spatio-temporal coupling controlled laser for electron acceleration. Communications Physics (2022).
5. Ionization loss spectra of high-energy protons in an oriented crystal at various incidence angles with respect to a crystalline plane. European Physical Journal C (2024).
6. Dielectric Laser Accelerators Driven by Ultrashort, Ultraintense Long-Wave Infrared Lasers. Ultrafast Science (2023).
7. Comprehensive study of beam focusing by crystal devices. Physical Review Accelerators and Beams (2018).
8. Reducing Beam-Related Background on Forward Physics Detectors Using Crystal Collimation at the Large Hadron Collider*. Physical Review Applied (2020).
9. The possibility to measure the magnetic moments of short-lived particles (charm and beauty baryons) at LHC and FCC energies using the phenomenon of spin rotation in crystals. Physics Letters B (2016).