NON-EVAPORABLE GETTER COATING ON SMALL DIAMETER VACUUM CHAMBERS WITH APPLICATION ON PARTICLE ACCELERATION
→
Europe/Zurich
30-7-018 (CERN)
30-7-018
CERN
Description
The increase in particle beam energy has induced a reduction of the vacuum chambers diameter, which can be a major hindrance for thin films deposition, namely if applied by Physical vapour deposition (PVD) technics. Nowadays, the method widely used consists of sputtering the coating inside a finished chamber; this process is limited by the creation of plasma, which mainly depends on the free space between the cathode and the chamber wall. So the feasibility of a novel procedure to coat vacuum chambers, of small section, with a Non-Evaporable Getter (NEG) is investigated on this project. The NEG deposition (a Ti-Zr-V ternary alloy) is done before the creation of the chamber: at first the getter is deposited by DC magnetron sputtering on a sacrificial aluminium mandrel, then via electroforming, a thick layer of copper (around 2.5 mm) is created, constituting the wall of the chamber. Next, flanges are assembled, and finally the aluminium mandrel is dissolved in a 5M concentrated caustic soda solution, leaving only the getter covering the inner surface of the tubular chamber. To define the right mandrel material and to study the efficiency of the route, the procedure has been initially applied on small kapton foils and on aluminium (purity 99.0%) platelets. The X-ray Photoelectron Spectroscopy technique was used to characterise the getter composition, before and after thermal activation. Besides the foils/platelets, tubular samples made of different aluminium alloys (diameter 80 mm, length 200 mm, wall thickness 0.5 mm) were also submitted to the novel coating technique, with the purpose of creating vacuum chambers. Pumping speed measurements, a further performance evaluation, was also performed on the NEG-coated tubes, to confirm the feasibility of this procedure.
09:00
→
09:30
NON-EVAPORABLE GETTER COATING ON SMALL DIAMETER VACUUM CHAMBERS WITH APPLICATION ON PARTICLE ACCELERATION30m
