8 m Interferometer Vacuum Calculation

Calculation for Pfeiffer Vacuum Calculator:

Central vessel:

Treating as a cylinder

11.9 inch radius

11 inch height

 

V = pi*r^2*h = 4900 in^3 = 0.080 m^3

SA = 2*pi*r*h + 2*pi*r^2 = 1,700 in^2 = 1.1 m^2

End cube:

Treating as a cube, even though the inside is more spherical

L = 10 in

 

V = L^3 = 1,000 in^3 = 0.016 m^3

SA = 6*L^2 = 600 in^2 = 0.39 m^2

 

Tubes:

4 inch radius

275 in height (two 10 ft tubes + 1 ft T = 6.4 m, round up to 7 m including gate valve, reducer, etc)

V = pi*r^2*h = 13,800 in^3 = 0.23 m^3

SA = 2*pi*r*h = 6,900 in^2 = 4.5 m^2

 

Total:

Vessel + 5 Cubes + 2.1 Tubes (power recylcer ~0.7m):

V = 0.643 m^3 = 643 L

SA = 12.5 m^2

 

Assumed desorption: 1e-8 mbar*l/(s*cm²)

Assumed leak rate: 3e-9 mbar*l/s

Can then figure out what pumps and how many to use using the calculator