Figure 6
Swelling of acrylic sheet with variation in temperature of the sample backplate during exposure. The squares and triangles correspond to samples exposed while the storage ring was operated at 1.3 and 1.5 GeV electron energy, respectively. The exposure conditions were beamline XRLM3; 125 µm Be window; 300 µm × 40 mm × 40 mm PMMA resist; Goodfellow (CQ); pre-exposure annealing at 353 K for 1 h (ramped) in N2; dose at resist bottom = 3 kJ cm−3. Mask: large mesh; scan length: 2.5 cm; scan velocity: 6.25 mm s−1; He pressure in chamber: 100 T. For accuracy of swelling measurements, see §2. |