Unit conventions

Xtrack follows a mostly SI-based convention, with accelerator-specific exceptions for particle energies and momenta. The elementary charge \(e\) is the unit charge, and \(c = 1\) is assumed.

Note

The following are general conventions adopted for Xsuite, however units should always be documented on elements and APIs directly. This page should especially serve as a guideline for the creation of new elements and APIs.

Core quantities

Quantity	Unit
Length, position	\(\text{m}\)
Time	\(\text{s}\)
Energy	\(e\text{V}\)
Momentum	\(e\text{V}/c = e\text{V}\)
Mass	\(e\text{V}/c^2 = e\text{V}\)
Charge	\(e\)
Voltage	\(\text{V}\)
Magnetic field strength	\(\text{m}^{-n}\), with \(n = 1\) for dipole, \(n = 2\) for quadrupole, etc.
Frequency	\(\text{Hz}\)
Geometric angles, RF and optics phases	\(\text{rad}\)