Optimization of Polishing Methods to Prepare Fused Silica Radiators for the HL-ZDC

The High Luminosity Zero Degree Calorimeters (HL-ZDCs) for the Large Hadron Collider (LHC) Run 4 will use 8000+ radiation-hard fused silica rods as Cherenkov radiators to characterize the geometry of heavy-ion collisions. High optical transmittance is crucial to maximize the Cherenkov signal output, and it critically depends on the surface polish of the rods. We investigate multiple polishing methods to increase the surface quality of these materials, including hand and machine polishing. To benchmark the methods, we measure light transmission across a wide range of wavelengths and correlate these results with the microscopic appearance of the surfaces. This correlation enables efficient visual assessment of the polish quality that will be used to polish the 8000+ rods needed for the HL-ZDC.