Fig. 1. Schematic diagram of the Thomson/Compton scattering process. A relativistic electron beam collides with a scattering laser. The electrons oscillate and emit X-/gamma-rays. Here, denotes the collision angle between the laser and the electron beam, represents the radiation observation angle, signifies the central frequency of the scattering laser photon and corresponds to the frequency of the emitted photon.

Fig. 2. (a) Schematic diagram of the experimental layout with multiple collision angles. (b) Radiation energy under different collision angles with electron energy from 100 MeV (blue) to 300 MeV (red) when the observed angle . The cases of and are specifically marked to correspond with the experimental results discussed later in Section 3.2.

Fig. 3. Diagnosis results of the electron beam with different acceleration lengths or plasma densities. From (a) to (e), the corresponding plasma densities are , , , and , respectively, with acceleration lengths of 10, 9.5, 9, 8 and 8 mm.

Fig. 4. (a), (b) Experimental layout diagrams of AOICS under two conditions of and collision angles, respectively. (c), (d) Radiation spectra with error bars for collision angles of and , respectively. The corresponding electron energy spectrum for each instance is displayed in the upper right-hand corner of each graph.

Fig. 5. (a) Experimental layout. The polarization state of the X-ray was obtained by placing the polyethylene (PE) forward in the X-ray and placing four image plates around it to diagnose the signal scattering in different polarization states. (b) Schematic representation of Compton scattering of linearly/circularly polarized X-rays with PE scatterers. The red portions indicate the distribution direction of the scattered electrons. (c), (d) Simulation results by FLUKA software, corresponding to the respective Compton scattering signals of linearly polarized and circularly polarized X-rays with PE. (e), (f) Experimental diagnostic results of linearly polarized and circularly polarized X-rays, respectively. (g), (h) The signal image formed by black dots is the one-dimensional integral result of the experimental results, while the dashed blue line represents the simulation results.

Fig. 6. The relevant international experimental progress and proposals^{[3–6,11–17,71–80]}. The solid-colored sections represent experiments that have been completed or are currently being planning, while the hollow elliptical regions correspond to the parameter ranges associated with the three phases discussed in this paper. The ranges corresponding to the classical radiation-dominated regime (CRDR) and the quantum radiation-dominated regime (QRDR) are indicated.

Fig. 7. (a) The signal intensity distribution on the image plate in the collision angle ICS experiment, along with the corresponding types of metal filters and their respective thicknesses. (b) The transmission curves for different energy intervals are obtained by subtracting the transmission rates of adjacent filter combinations, where the annotated numbers correspond to the numbers in (a).

Fig. 8. (a) The signal intensity distribution on the image plate in the collision angle ICS experiment, along with the corresponding types of metal filters and their respective thicknesses. (b) The radiation transmittance curves of different metal filters varying with energy.

Fig. 9. The overlap geometry of the experimental schematic diagram.