Fig. 1. Oxygen-free copper samples

Fig. 2. Emissivity of three oxygen-free copper samples at different temperatures

Fig. 3. Test of the outgassing rate of blackened oxygen-free copper sample

Fig. 4. Outgassing rate of the three oxygen-free copper samples

Fig. 5. Temperature distribution of the collimator absorber with different surface treatment

Fig. 6. Distribution of the ion pumps and cold cathode gauges in R₁ section

Fig. 7. Distribution of pressure in half of the R₁ section with different conditions