X-Ray Fluorescence Spectrum
- X-Ray Fluorescence (XRF) spectrum:
recording a XRF spectrum takes usually no more than 30 sec (start with 5 sec of exposure).
- the XRF spectrum is not destructive (a minimal transmission of the beam will be taken).
- the XRF spectrum is more sensitive than an absorption edge scan (this makes it ideal to check for heavy atoms in your crystal).
- you work at a specific energy. This means that you will only detect fluorescence from elements that have their fluorescence line about 1 keV below the incident beam energy.
- you do not need to have a well diffracting crystal to perform a XRF spectrum, any bad crystal, crystal shower or even highly concentrated protein solution will do.
- you will detect everything that is in your crystal and in the surrounding mother liquor.
- your raw data are automatically written to an prefix_date.png file within the directory you have defined.
start an XRF spectrum by choosing a prefix name and the directory. 5 sec of exposure time (count time) is a good start. Then press Start Spectrum
Within the graph brick within MxCuBE you will see three different graphs: your raw data (minus the Compton and the Rayleigh scattering peaks) are shown in black, the calculated fit in red and the continuum in green. Only elements that naturally occur in proteins will be automatically fitted.
By clicking with the left mouse button on a peak a window will open with all possible elements that have their fluorescence line at this particular energy.
Keeping the left mouse button pressed allows you to zoom into an area, to zoom out again, simply click with the right mouse button into the graph brick.
you can save your data (as a raw ASCII file or a .png/.eps file) and the calculated fit by clicking on the diskette button directly above the graph. If you like to save an HTML report click on this button located below the graph.