Soft X-rays spectroscopy with a commercial CMOS image sensor at room temperature

Besides their application in point and shoot cameras, webcams, and cell phones, it has been shown that CMOS image sensors (CIS) can be used for dosimetry, X-ray and neutron imaging applications. In this work we will discuss the application of an ON Semiconductor MT9M001 CIS, in low energy X-ray spectroscopy. The device is a monochromatic front-side illuminated sensor, very popular in consumer electronics. In this work we introduce the configuration selected for the mentioned sensor, the image processing techniques and event selection criteria, implemented in order to measure the X-ray energy in the range from 1 to 10 keV. Several fluorescence lines of different samples have been resolved, and for first time the line resolution have been measured and analyzed. We achieved a FWHM of 232 eV at 6.4 keV, and we concluded that incomplete charge collection (ICC) of the charge produced by the X-ray contributes to the resolution, being this effect more important at higher X-ray energies. The results analyzed in this work indicate that the mentioned CIS are specially suitable for X-ray applications in which energy and spatial resolutions are simultaneously required.