G. Y. Hsiung 1

1
Test for the AL Chambers with interior NEG coating
Workshop on Vacuum Systems for Synchrotron Light
Sources, Barcelona, SPAIN, 12 -13 Sep. 2005.
Gao-Yu Hsiung (???) Vacuum Group NSRRC, Taiwan
2
Contents

• Activation for NEG (180 C for 20 hours)
• Test in the clean room
• Test for Dust by knocking
• Test for Outgas by pressure build-up method
• Test at the 19B1(PSD) beam line
• Description of system
• Test for PSD
• PSD yield
• RGA Kr desorption

3
Test for Dust
HEPA (lt 10 particles in 5 min )
Collector
Particle Counter
No. of particles ltlt Al foil, or gloves (more than
hundreds in seconds)
73 particles in 5 min (static)
84 particles in 5 min (continuously knocking )
4
Curve of Activation for NEG Chambers at 180 C
for 20 hours
5
Pressure build-up at room temperature after
activation of NEG
Kr lt 0.4
Build up
Kr
Based pressure of the Al(NEG) chamber lt 5E-11
Torr.
6
NEG Chamber installed at 19B1(PSD) Beam Line for
Photon Exposure
NEG Chamber
RGA
IG
SR
ec 2.14 keV dF 1.8 mrad Flux 3.5E14
Ph/s/mrad/mA
C 6.8 L/s
7
Kr was found during activation of NEG at 180 C
for 20 hours
Kr lt 0.01
Kr
8
Test for PSD PSD yield (dP/I)
9
Comparison PSD yield between NEG Al chamber and
original Al chamber
NEG-Al-Ch
Al-Ch
10
Conclusions

• The aluminum alloy chambers with NEG coating has
  been tested
• Dust is low (after 5 min continuously knocking)
• Based pressure lt 5 E-11 Torr after activation.
• Kr molecules was found
• during activation at 180 C (lt 0.5 )
• during the pressure build up at room temperature.
  (lt 0.01)
• during SR exposure at PSD beam line. (not
  serious)
• The outgas Kr will reduce beam life time. (Watch
  out!!)