Fig 1.
Principle of PFAS treatment using EBWT with accelerator beams.
The electron beam irradiates the water and starts the radiolysis process. The created hydrated electrons can then react with the PFAS in the water and start the degradation process.
Fig 2.
Photograph of the SEALab accelerator platform.
Shown is the SRF photoinjector and diagnostic beamline. The straight section to the left leads to the experimental site.
Table 1.
Core parameters for the SRF photoinjector.
Initial SEALab specifications and demonstrated parameters [35], plus specifications for a dedicated EBWT mode and the proof-of-concept phase. Note that the demo parameters for SEALab have been observed with different SRF gun systems.
Table 2.
Sample holder geometry parameters.
Using FLUKA simulation, water depth and water radius were optimized.
Fig 3.
SEALab SRF photoinjector with water delivery system.
The electron gun and booster module accelerate the electron beam up to 6.5 MeV. The electrons can then proceed through the straight section, into the first bend, and reach the water experimental area (marked in red).
Fig 4.
Sketch of the accelerator and experimental setup.
Electrons will be accelerated and leave the beamline through a vacuum exit window. Then, they reach the water container where the PFAS degradation will take place.
Fig 5.
The electrons (red) and photons (yellow) are tracked in the x-z-plane from where they exit the vacuum through the exit window and then enter the water holder in the middle of the figure. To the right, the dose rate in the water sample is shown on a logarithmic scale.
Fig 6.
Average dose rate vs water radius.
FLUKA simulation study results. The water radius was increased, and the average dose rate in the water sample was simulated for different values. It can be seen that for this specific setup and for useful water radius ranges (larger than 1 cm), the change in
does not significantly alter the delivered dose.
Fig 7.
Average dose rate vs water depth of sample.
FLUKA simulation study results. The water depth was increased, and the average dose rate in the water sample was simulated for different energies. Note: This is not the dose rate distribution over the depth of the water sample.
Table 3.
Optimized with FLUKA and Ansys simulations.
Table 4.
Simulated values for the experiment using EBWT mode.
Fig 8.
Average dose rate vs depth of water sample.
FLUKA simulation study results. The dose rate is plotted over the depth of the water sample. The dose over depth was simulated for two energy options (2.5 MeV and 6.5 MeV). For the future 6.5 MeV beam, the depth of the water sample can be further increased.
Fig 9.
Average dose rate vs horizontal position in water.
FLUKA simulation study results. The average dose rate is plotted along the x-axis of the water sample at the point of entry.
Table 5.
Simulated values for the vacuum exit window.