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The usual accelerator coordinate system is assumed (see ref)
In GMAD the SI units are used.
Length
[m] (metres)
|
angle
[rad] (radians)
|
quadrupole coefficient
[m**(-2)]
|
multipole coefficient
2n poles [m**(-n)]
|
electric voltage
[MV] (Megavolts)
|
electric field strength
[MV/m]
|
particle energy
[GeV]
|
particle mass
[GeV/c**2]
|
particle momentum
[GeV/c]
|
beam current
[A] (Amperes)
|
particle charge
[e] (elementary charges)
|
emittances
[pi m mrad]
|
There are some predefined numerical values
pi
3.14159265358979
|
me
electron rest mass
|
mp
proton rest mass
|
GeV
1
|
eV
1^-9
|
KeV
10^-6
|
MeV
10^-3
|
TeV
10^3
|
m
1
|
mm
1^-3
|
cm
1^-2
|
rad
1
|
mrad
1^-3
|
clight
2.99792458e+8
|
for example, instead of one can write either 100 or 0.1 * KeV when energy constants are concerned.