One output file is created by the program - a data file whose name is user supplied (e.g. BIMODAL.MAX).
The first few lines of output of a typical output file are as follows:
Results of maximum entropy analysis of SAS
version 3.1 (PRJ) , edited:7 February 1990
input file: Bimodal.Sas
output file: Bimodal.Out
--------------------------------------------
N(D) dD is number of particles/cm**3
whose size is between D and D + dD
D, A V(D)*N(D), 1/A N(D), 1/A/cm^3 dD, A
---- -------------- -------------- -----
10.00 8.81630E-15 1.68379E+07 10.0000
20.00 2.16369E-14 5.16543E+06 10.0000
30.00 6.36171E-14 4.49999E+06 10.0000
The four columns are separated by TABs and also spaces.
| term | description |
|---|---|
| D | dimension of scatterer in Angstroms |
| V(D)*N(D) | volume-weighted differential number distribution |
| N(D) | differential number distribution |
| dD | width of the bin in Angstroms in terms of “D” |
V(D)*N(D) is the distribution solved by the program. N(D) is the distribution most often reported by other analysis techniques (TEM, mercury porosimetry, etc.). N(D) is calculated from the second one by dividing by the particle volume. This table continues as:
380.00 8.11590E-07 2.82480E+10 10.0000
390.00 5.74524E-07 1.84976E+10 10.0000
400.00 3.71052E-07 1.10728E+10 10.0000
Q 1/A I 1/cm ^I 1/cm dI 1/cm z
----- ------ ------- ------- ----
7.4936E-03 2.1200E+00 2.2330E+00 1.6700E-01 -0.676923
9.9975E-03 1.9000E+00 1.9596E+00 1.0200E-01 -0.584780
1.2501E-02 1.7840E+00 1.6605E+00 6.6900E-02 1.845438
These columns are also separated by a combination of spaces and tabs
| term | description |
|---|---|
| Q | input Q-vector in 1/Angstrom units |
| I | input intensity in 1/cm units |
| ^I | intensity calculated from the distribution above |
| dI | input error in 1/cm, scaled by the error scaling factor |
| z | standardized residual, z = (I - ^I)/dI |
9.2452E-02 4.3770E-03 4.2886E-03 1.6700E-04 0.529397
9.5008E-02 3.4510E-03 3.7178E-03 1.5000E-04 -1.778752
9.7564E-02 3.5330E-03 3.2077E-03 1.3500E-04 2.409922
9.9937E-02 2.9560E-03 2.7793E-03 1.2300E-04 1.436465
Input data: Bimodal.Sas
Contrast = 1.0000000 x 10^28 m^-4.
spheroid: D x D x D* 1.00000000000000
Data conversion factor to 1/cm = 1.00000E+00
After all the intensities have been printed, the same summary appears in the output file as appeared on the screen shown above. Only the first few lines are shown here.
The program creates two extra pseudo-particle sizes, one that is “smaller” than the smallest bin in the distribution and one that is “larger” than the largest bin in the distribution. The scattering from these pseudo-particles is approximated at low angles by the Guinier relation and at high angles by the Porod relation. The object of the user is to define the dimension range large enough that neither of these pseudo-particles develops any significant volume fraction. The percentage of the distribution that was assigned to each of these sizes is reported. Provided that both are small compared to the total volume fraction of scatterers (also given in the summary) then the program has detected essentially all of the particles contributing to the observed scattering. If they are not, it may be worth re-running the program with a different diameter range in order to detect this extraneous volume fraction.