View source for Monte Carlo code

The buffer gas Monte Carlo code is used for calculating the dynamics of magnetic dipoles evolving in the presence of buffer gas and/or magnetic fields.  The version here was written by Nathan Brahms based on the method given in Bob Michniak's thesis.

== Downloading ==

Version 3 of the Monte Carlo code can be downloaded [http://cua.harvard.edu/~lithium/Trap%20Simulation/BGMonteCarloV3.zip here].

Just unzip the archive into a new folder and follow the instructions in <code>README.html</code>.

== Description ==

Some of the things this code can be do are:

* Calculate the free evolution of a magnetic atom in a magnetic field.
* Calculate a Monte-Carlo trajectory of a magnetic atom in a cell with a magnetic field present, subject to collisions from a background gas. The user can also perform the same calculation without a magnetic field.
* Make a histogram of the number of Monte-Carlo atoms having left a cell volume vs. time, for magnetic atoms in a cell, starting from a given distribution.
* Calculate a Monte-Carlo distribution of atoms after a specified number of collisions or after an amount of time, starting from a given distribution.

The calculations are performed by first generating a spatial and velocity distribution of dipoles.  Each dipole then evolves by classical kinematics.  The dipole evolves under the influence of a local magnetic field.  After a time, randomly chosen from an exponential distribution, the dipole collides with a random buffer gas atom, with velocity randomly chosen from a Boltzmann distribution.  The dipole then evolves under the magnetic field until its next collision.  The evolution continues until either a fixed number of collisions has been reached, a set amount of time has passed, or the dipole leaves the geometry of interest.

== Help ==

For help with the code, please first see the code <code>README.html</code> file.  If that fails, questions may be direction to Nathan Brahms.