X-ray Beam Width Measurements

A radiochromic film (Gafchromic EBT3-1417, Lot # 09241801, Ashland Global Specialty Chemicals Inc., DE, USA) was roughly cut into small rectangular pieces and placed at 5 mm intervals in a 3D-printed holder that had 15 slots 5 mm apart. The holder with pieces of the radiochromic film was placed vertically under the X-ray beam with the radiochromic piece in the 0 mm slot directly in contact with the focusing optics (polycapillary) of the X-ray and exposed to the X-ray beam (at 50 kV and 600 μA) for 30 s. The spot size was measured with ImageJ software.