University of Minnesota
Characterization Facility
X-ray Scattering Facility
SAXS—6 meter line
1. Turn on the helium using only the
5. Using the drop-down menu at the
top of the software window, choose:
Special, Commandmode.
knob at the top if the helium tank.
Switch the flow to flood while loading
sample and logging onto the
computer.
2. Slowly turn the instrument bias to
3.5.
3. Log onto the computer: Username:
code number; Password: Hrmc$567
then you will be prompted to change
it; Domain: Charfac.
4. Open the detector software: Start,
Bruker AXS programs, SAXS nodiff.
Compare the distance in the
instrument’s logbook with the
distance in the bottom, right corner
of the page.
Bias
Distance
You will get a ―SAXS>‖ prompt at the bottom of the page.
6. Run a quick scan with a sample that scatters well (preferably isotropic) to check the
instrument and it’s calibration.
a. @expose 20
b. @correct
c. cal (the circles of the bullseye calibration should be aligned with the sample)
1
7. Check the integration settings—type ―int‖
a. Enter the correct step size for the distance. Step size is a function of the
sample-to-detector distance. The larger the sample to detector distance, the
smaller the step size.
Common step sizes are:
Sample to Detector Dist.
Step Size
58 cm
0.01
104 cm
0.006
150 cm
0.004
200-420 cm
0.002
b. Enter the correct ―normalize intensity‖ value. The normalization techniques
are explained in detail in the ―help‖ menu. Ordinarily, for SAXS ―0 – sum
pixels‖ is used—that will magnify the intensity of the higher order peaks.
c. After entering the step size and normalization factors, hit ―enter‖ to
interactively select the 2theta and chi integration values.
d. Make sure the correct format is chosen. PLOTSO will save as an ascii
format, DIFFRAC-AT will save in a format that is easily read into the WAXS
software program JADE. Make sure the scale factor is also what you want.
This is the number that will be used to multiply each intensity value.
2
8. Edit your macro with the correct integration values and folder information (create a
folder if you’d like) and save as an *.slm file.
9. Begin your sample analyses by using your macro:
a.
b.
c.
d.
e.
f.
Insert sample, check position with flashlight and mirror.
Close door and check vacuum of tube—should be about -28.
Open the brass mechanical safety switch on the brass tube.
Run @expose 20 to check scattering.
Run data collection macro or 1 second to check that it works properly.
Begin data collection.
When Done
1. Transfer your files via the charfac server, netfiles, or e-mail.
2. Delete your data files from the hard drive.
3. Turn off the helium.
4. Turn the bias down to zero.
5. Sign out on the computer.
Quick Start
1. Turn on Helium (―flood‖ for about 5 minutes, then ―slow purge‖ for the rest of the
time)
2. Turn up Bias (3.5)
3. Load ―SAXS No Diff‖ software and compare distance with value in logbook.
4. Load sample (or standard) and check scatter:
a. @expose 20
b. @correct
c. Cal -- make sure center looks good
5. Edit data collection macro if necessary; begin data collection after checking
macro with a 1 second scan.
3
Macros and Common Commands
Most of the work will be done using macros. Macros must begin with the ―@‖ symbol.
The most common macro is: @expose xx where xx is the amount of time you’d like to
collect data. @expose will open the shutter, collect for XX seconds, close the shutter.
You may also open or close the shutter by typing the following: SAXS>system
closeshutter or SAXS>system openshutter. Other commonly used macros and
commands are:









@correct (this will unwarp the data)
@stemp xx (this will change the temperature to xx degrees.) The temperature
range is -15 to 200C.
int will take you to the integration menu
peaks will plot the integrated peaks
cal will take you to the calibration menu
config will take you to the configuration menu
save will take you to the save menu
load will take you to the file loading menu
menu will return you to the general software, pop-up menu
Macros can be combined to execute a series of commands. For example, you can use
a macro to open the shutter, collect the data, save the data, unwarp the data, save the
corrected pattern, integrate the data, print the data (either to a printer or to a *.bmp file)
and then change the temperature, hold for a few minutes or several hours, and repeat
the process. All macros are all saved in the c:\saxs\ directory and have an ―slm‖
extension. You may use other people’s macros as a starting point for creating your own,
but make sure you rename them. The following macro is used for general data
collection:
@expose %1
save e:\sauer\'%2' /title='%3'
@correct
save e:\sauer\'%2'.cor /title='%3'
integrate /chi 0.5 5 -160 -10 /stepsize=0.01
integrate /write '%3' /filename=e:\sauer\'%2'.raw
The ―%#’s‖ are wildcards and you need to enter the values after the macro’s name. For
example, in the above macro, called lsfl_exp, the %1 corresponds to the amount of time
the shutter will be open, %2 is the filename (no punctuation marks), and %3 is the title (if
you put it in quotation marks, you can type anything you want.) To use the macro to
collect a scan for 5 minutes, name it test with a title of ―This is a test‖, you would type:
SAXS>@lsfl_exp 300 test ―this is a test‖.
Editing of macros is done in notepad and all files should be saved as *.slm files (make
sure the bottom box says ―all files‖ instead of ―txt files‖.
For Kapton
Contact Dupont and ask for samples of Kapton 100HN Polyimide Film:
Dupont , K/T Customer Service, P.O. Box 89, Circleville, OH 43113
Product Information: 1-800-237-4357
Ordering Information: 1-800-967-5607
4
Data Ranges for Various Sample-to-Detector Distances
2D-Small Angle X-ray Scattering
Sample to Detector
Distance
d-spacing (A)
28 cm
50 cm
100 cm
150 cm
230 cm
98 – 8
220 – 17
300 – 30
350 – 50
830 – 70
2-theta
d
q
Data Range
q (A-1)
two-theta
0.064 – 0.78
0.028 – 0.37
0.021 – 0.21
0.018 – 0.13
0.007 – 0.09
2 meter
0.12—1.43/0.0056
62-770 angstroms
.13 to .008
0.9 – 11.0
0.4 – 5.0
0.3 – 3.0
0.25 – 1.8
0.1 – 1.3
6 meter
0.046—0.57/0.0022
155-1930 angstroms
.04 to .0033
No birefringence (not cloudy or rainbow when looking through crossed-polarizers and
light) means isotropic—disordered, or cubic—if it’s truly mixed, there is no contrast at
all. Anisotropic means layered structure.
Porod region at the higher angle gives information on boundary thicknesses between
structures.
SAXS Peak Positions
1, 2, 3, 4, 5, 6, 7, …
Structure
BCC (with 7 ) or simple cubic
3, 4, 8, 10, 11
FCC
1, 3, 4, 7
Hexagonal
1, 2, 3, 4, …
Lamellar
3, 4, 7, 8, 10, 11
Gyroid
Equations:
q = 4*pi*sin(2theta/180*3.14/2)/lamda
lamda=2dsin(theta), d=2pi/q
q=4pi*sin(2theta/2)/lamda
5
6