A compact light source providing high-flux, quasi-monochromatic, tunable X-rays in the laboratory

Abstract

There is a large performance gap between conventional, electron-impact X-ray sources and synchrotron radiation sources. Electron-impact X-ray sources are compact, low to moderate cost, widely available and can have high total flux, but have limited tunability (broad spectrum bremsstrahlung plus fixed characteristic lines) and low brightness. By contrast, synchrotron radiation sources provide extremely high brightness (coherent flux), are tunable and can be monochromatized to a very high degree. However, they are very large and expensive, and typically operated as national user facilities with limited access. An Inverse Compton Scattering (ICS) X-ray source can bridge this gap by providing a narrow-band, high flux and tunable X-ray source that fits into a laboratory at a cost of a few percent of a large synchrotron facility. It works by colliding a high-power laser beam with a relativistic electron beam, in which case the backscattered photons have an energy in the X-ray regime. This paper will describe the working principle of the Lyncean Compact Light Source, a storage-ring based ICS source, its unique beam properties and recent developments that are expected to increase flux and brightness by an order of magnitude compared to earlier versions. Furthermore, it will illustrate how such an X-ray source can be the cornerstone of a local X-ray facility serving applications from diffraction and imaging to scattering and spectroscopy. An overview of demonstrated and potential applications will be provided.

Precision radiotherapy using monochromatic inverse Compton x‐ray sources

“…2(a) include their respective geometric penumbra. The small size of the IC source in the MC calculations (Section 2.A) is consistent with existing IC sources 3,6 and allows for sharp penumbra. The 250 kV p penumbra is between 0.6 and 0.8 mm (for depths 0-5 cm), which is intermediate between the IC and megavoltage Bremsstrahlung sources, as might be expected from the focal spot size and maximum energy.…”

“…Beam scanning may also be employed. The field sizes of both IC beams were collimated to a 3 cm diameter circle at isocenter using a tungsten collimator of thickness 1 cm located 60 cm from isocenter 3,6 . To evaluate the dosimetric properties of the IC beams, depth‐dose and dose profiles simulations were performed for both energies in a water phantom where the surface of the water phantom was placed at isocenter.…”

“…The radiation field was collimated to 3 Â 3cm 2 using the jaws and the source-surface-distance was set to 100 cm for the TPS dose calculations. The dose calculation grid resolution for all TPS dose calculations was 1 Â 1 Â 1mm 3 . Dose calculations with the TPS were made in analogous irradiation setups to the egs brachy simulations to allow for a direct comparison.…”

“…Compact, inverse Compton (IC) x‐ray sources have been shown to produce photon beams of similar quality, divergence, and bandwidth as bending magnet synchrotron x‐ray sources 3 . IC sources use optical lasers instead of magnetic fields to perturb MeV‐energy electron beams, which results in scattered x‐ray photon beams that are pseudo‐monochromatic (bandwidth, Δ E / E ∼ 10%) and have low divergence (half‐angle ).…”

Energy-Dispersive X-ray Absorption Spectroscopy with an Inverse Compton Source

“…The MuCLS is a laboratory x-ray facility 20 with two end-stations equipped with multi-purpose x-ray experimental setups 30 . The ICS source of the MuCLS is manufactured by Lyncean Technologies Inc., Fremont, USA and this commercial ICS source is available at a cost of a few percent of a large synchrotron facility 34 . The investment for an entire facility similar to ours, including radiation shielding, infrastructure and a beamline with two endstations in addition to the source, is in the range of 12-18 million Euro, but depends strongly on the specific local conditions.…”