In the areas between absorption shells, the distribution usually follows simple power laws, but the shell structure is in general not something which can be neglected.
Format:
CLUSTER FUNCTION cluster_function [N nmax]
Example:
cluster function 1/n^3 n 15
Doing this will produce a warning since, to compute probability to have a cluster size of 0, one would divide by zero.
Additional information on:
Please note that the first number is the probability to have a cluster size of 0, i.e. a cluster without ionisation electrons. When a charged particle traverses a gas, most interactions result only in excitation, not in ionisation. If you set a mean number of clusters per cm which only takes clusters into account that contain at least 1 electron, then you have to set the first probability to 0.
Format:
CLUSTER prob_size0 prob_size1 ... (blank line)
Example:
CLUSTER 0 0 0.1 0.2 0.5 0.2 0.1 0// Note that the preceding line is left blank
Format:
CLUSTER FUNCTION cluster_function [N nmax] OVERLAP-TABLE-AND-FUNCTION prob_size0 prob_size1 ... (blank line)
Example:
CLUSTER FUNCTION 21.6/N^2 N=200 OVERLAP 0 86 20 10
There has to be a blank line after the cluster sizes. One can also simulate this format by using a Do loop:
cluster
0 86 20 10
For i From 4 To 200 Do
{21.6/i^2}
Enddo
// Note that the previous line is left blank !
But this would be less efficient since the formula inside the loop (21.6/i^2) is translated each iteration of the loop. Note that there has to be a blank line after Enddo.
A more efficient version of the latter would be:
cluster
0 86 20 10 {21.6/row(200)^2}
// Note that the previous line is blank !
Formatted on 21/01/18 at 16:55.