1：Experimental Design and Method Selection:

The experiment involved coating a test chamber with Ti and Pd thin films using vacuum sublimation to create NEG coatings, followed by activation through baking and testing pumpdown performance after multiple venting cycles. The rationale was to achieve low oxygen concentration in the films for better durability.

2：Sample Selection and Data Sources:

A stainless steel 304L test chamber with electropolished inner walls was used. Data on pressure and temperature were collected during pumpdown and after valve closure.

3：List of Experimental Equipment and Materials:

Equipment included Ti sublimation pumps, Pd sublimation filament, turbomolecular pumps, butterfly valve, Bayard-Alpert nude ionization gauge, thermocouples, heaters, and a thin film rate/thickness monitor. Materials included Ti and Pd wires.

4：Experimental Procedures and Operational Workflow:

The chamber was first coated with a 1-μm Ti film under 6.5×10?? Pa vacuum using Ti sublimation pumps. Then, it was coated with a 10-nm Pd film under 2.4×10?? Pa vacuum using a Pd filament. The coated chambers were baked at 185°C for 6 hours, and pumpdown curves were measured after venting with dry N2, dry air, or air. Pressure was monitored after closing the valve.

5：5×10?? Pa vacuum using Ti sublimation pumps. Then, it was coated with a 10-nm Pd film under 4×10?? Pa vacuum using a Pd filament. The coated chambers were baked at 185°C for 6 hours, and pumpdown curves were measured after venting with dry N2, dry air, or air. Pressure was monitored after closing the valve. Data Analysis Methods:

5. Data Analysis Methods: Pressure data were analyzed to estimate pumping speeds using equations based on outgassing rates and pumping speeds. Statistical comparisons were made between uncoated, Ti-coated, and Pd/Ti-coated chambers.