re 2.768[mm] "Rod radius"
r0 re/1.147 "Inscribed radius"
rsrc 0.75[mm] "Source radius"
rcase 4*re "Case radius"
Lquad 127[mm] "Quadrupole length"
a 0.05 "Mathieu coefficient"
q 0.7 "Mathieu coefficient"
f 4[MHz] Frequency
omega 2*pi*f "Angular frequency"
mi 40[amu] "Ion mass"
Vac q*mi*omega^2*r0^2/(4*e_const) "AC voltage"
Udc a*mi*omega^2*r0^2/(8*e_const) "DC voltage"
A 2[V] "Accelerating voltage"
vx0 sqrt(2*e_const*A/mi) "Initial x velocity"
fd 2[mm] "Fringe field depth"