Summary:
The Free-Electron Laser (FEL) is a versatile and powerful light source with tunable wavelengths, enabling applications across fields such as atomic and molecular physics, biology, chemistry, particle physics, and astrophysics. John Madey, the inventor of the FEL, established this lab within the Department of Physics and Astronomy at the University of Hawaii at Mānoa. The lab houses a linear electron accelerator and an FEL oscillator, which produces infrared photons. These photons are used in an inverse Compton scattering configuration to generate hard X-ray photons.
Machine Specifications:
(Niknejadi, Pardis, et al. “Free-electron laser inverse-Compton interaction x-ray source.” Physical Review Accelerators and Beams 22.4 (2019): 040704.)
TABLE. Current design and experimental operating parameters for FELICIA. The flux and brilliance are calculated from the experimental values as a reference.
| Symbols and parameters | Design | Experiment |
|---|---|---|
| rf/electron pulses | ||
| ƒrƒ rf frequency (GHz) | 2.856 | 2.856 |
| Imp macropulse current (mA) | 170 | 143 |
| τmp macropulse duration (μs) | 5 | 5 |
| ƒmp macropulse frequency (Hz) | 100 | 4 |
| Qμp micropulse charge (pC) | 60 | 50 |
| τμp micropulse duration (ps) | 2 | 1-2 |
| Ɛe electron bream energy (MeV) | 40 | 42.2 |
| ϵn normalized emittance (π-mm-mrad) | 8 | 25 |
| Laser pulses | ||
| λ0 laser wavelength (μm) | 3 | 3.1 |
| Ƥ1 laser power (MW) | 2.6 | 0.3 |
| Interaction point | ||
| w0 laser beam waist (μm) | 30 | 30 |
| rms electron beam size (μm) | 30 | 53 (42 x 64) |
| Ƒ storage cavity finesse | 2000 | … |
| Ƥs stored optical power (GW) | 2.6 | … |
| Scattered x-rays | ||
| Ɛγ x-ray energy (keV) | 10 | 10.9 |
| λγ x-ray wavelength (Å) | 1.2 | 1.1 |
| Ƒγ total average x-ray flux (ph/s) | 2.1 x 1011 | 3.0 x 105 |
| θ = 1/γ x-ray divergence angle (mrad) | 12.6 | 12.1 |
| Bave average brilliancea | 7.6 x 108 | 1.3 x 105 |
| Bpeak peak brilliancea | 3.3 x 1014 | 3.7 x 109 |
| aphotons/smm2mrad2 0.1% BW.1 |