- Output from Monte Carlo code is value of integrals over
distribution function
*f*:

- Consider random walk of
*k*steps, ionized at*t*_{k}: . - Next collision probability (density) between
*t*and

in constant background volume*V*:

- scattering (all non-ionizing processes) rate,
- Then,

- probability for particle having collision for
*any*,

- Sample
*P*(*t*) uniformly by choosing PRN , , setting:

- Length of track
*t*determined by first of:- Particle leaves
*V*, - Or have a collision.

- Particle leaves
- We assume suppressed absorption
- Explicit collisions don't include ionization,
- Ionize gradually along track better efficiency,
- At end of step reduce statistical weight by ,

- Monte Carlo representation of desired integral:
,
- probability of walk ,
- Sampled uniformly in practice .

- is estimator of function
*g*in*V*.

Wed Nov 26 10:29:07 EST 1997