X-Ray Fluorescence

1. X-Ray Fluorescence How it will be employed in Sphinx?

2. X-ray fluorescence When the X-rays go through any material they are absorbed by photoelectric effect. As the result atoms of the material lose electrons of inner shells. Excited atoms may radiate characteristic X-rays named fluorescence radiation. Typically fluorescence radiation is undesirable giving increase of the background level. Here we are making use of the fluorescence in a new, positive way by incorporating this process for in-flight energy calibration of the detectors gain and for new-concept narrow-band solar photometry.

3. Sharp passband photometry Solar radiation Filter Target Detector Fluorescence

4. Filtered and active Sun radiation

5. Combinations and passbands • We will use three sets of filter + target • Set Passband (pm) • Al+Mg 794.8 – 951.2 • Ti+Ca 249.7 – 307.0 • Fe+Cr 174.3 – 207.0

6. Expected counts caused by M1 class flare (EM= 1.0x1049 cm-3)

7. Fluorescence from three targets used (Mg,Ca,Cr) will be detected by one detector only

8. In-flight energy calibration of the detector using X-ray fluorescence Solar X – ray radiation Targets on movable cover Targets on movable cover Fluorescence Fluorescence Detectors Detectors

9. Lines used for the calibration Material Line Energy [keV] Al Kα 1.486 Al Kβ 1.557 Ti Kα 4.509 Ti Kβ 4.932 Cu Kα 8.041 Cu Kβ 8.905

10. Expected counts caused by M1 class flare (EM= 1.0x1049 cm-3)

11. Expected amplitude spectrum for one of three detectors