Helium tightness
SDMS is the french leader in the manufacture of vacuum chambers and
UHV for Research, micro-electronics, Cryogenics, Space, Nanotechnologies.
Helium tightness and EB welding
EB welding of the half-shells of the 20 mm thick
copper tube then of the copper tube (thickness = 20 mm) on the 316L stainless
steel tube, 250 mm in diameter, helium-tight, no deformation, no heating
of soldering already completed.
EB welding of Copper plates (thickness = 3 mm), helium
tight, no deformation, no heating of soldering already completed
Helium tightness and outgassing
Our tightness test experience only concerns secondary
vacuums up to 10-5 Pa. We have generally observed an
outgassing that is slightly greater than for stainless
steel. On the above parts for the LEP 200 (3 m3), pressure after 24 hours
of pumping reached 10-4 Pa (pumping by turbomolecular pump 500 1/s). The
outgassing rate after 1 hour is around 10-7 Pa.m/s- 1. Sensitivity of the
helium test is the same on aluminium and stainless steel (i.e. 5.10-11
Pa.m3.s-1 with very clean vessels).
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