Estimation of Nitrogen content in TPCs

1
Estimation of Nitrogen content in TPCs
CERES NA49 ALICE design ALICE expected
F (l/h) 2000 4000 20000 20000
f (l/h) 120 400 30 30
O2 (ppm) 10 2 5 0.5
l (l/h) 0.1 0.04 0.5 0.05
N2 (ppm) 700 80 13300 1330
2
N2 content vs. fresh gas injection

• Time constant 100 m3 / fresh gas/h

3
Ne Cost
4
Gain variation with Nitrogen
5
Conclusion

• 5 ppm O2 not a comfortable value
• measure and control leak rate of all components
• shoot for as low as possible total leak