The 1D output files of "annular" averaged SANS data are of the format below. In this average, a ring at constant q is selected with a width of N pixels, and is averaged into M angular bins. The default number of angular bins, M, is set to 72, and can be changed in the Reduction package preferences. In the output file, there is a header of information describing the sample information (gleaned from the raw data file) and information about the processing steps that were taken to generate the reduced data file. The data is in a 3-column format where the 3 columns are:

1- phi (degrees)
2- I(phi) (1/cm)
3- standard deviation of I(phi) (1/cm)

The 2D detector is a normal XY coordinate system when viewed from the neutron source. For the annular average, zero angle (phi) is the positive X-axis, and increases counter-clockwise around q=0. (or anti-clockwise...)

(only a snippet of the file is shown here)

FILE: SILIC009.SA3_SRK_S109		 CREATED: 22-JAN-2008 02:39:11
LABEL: Silica 2 pct in D2O Scatt 1.3M                              
MON CNT   LAMBDA   DET ANG   DET DIST   TRANS   THICK   AVE   STEP
7.6329e+06  6       20     1.33     0.72501     0.2C   1
BCENT(X,Y)   A1(mm)   A2(mm)   A1A2DIST(m)   DL/L   BSTOP(mm)   DET_TYP 
106.8  64.59  50    3    5.4675    0.142    50.8    ORNL  
SAM: SILIC009.SA3_SRK_S109
BGD: Unknown file from Average_Panel
EMP: Unknown file from Average_Panel
DIV: Unknown file from Average_Panel
MASK: Unknown file from Average_Panel
ABS Parameters (3-6): Unknown file from Average_Panel
Average Choices: Unknown file from Average_Panel
The 3 columns are | Phi (deg) | I(phi) (1/cm) | std. dev. I(phi) (1/cm) |
              0           302.8           19.03
              5           256.8           13.48
             10           331.9           15.35
             15           286.6           19.86
             20           298.5           11.18
             25           295.4           16.19
             30           300.2           17.84
             35           273.2           11.87
             40           284.6            13.5
             45           277.3            13.8
             50           291.6           23.07
             55           273.4            19.8
             60           263.3           19.41
             65             288           25.21
             70             280           21.35
             75           268.3           23.86
             80           286.9           26.86
             85           294.4           33.18
             90             271           23.13

Back Up to Previous