Location of the source of soft X-ray non-thermal line broadenings in a solar flare

We determine the location of the source of the nonthermal Soft X-ray line broadenings in an M1.7 two-ribbon solar flare using multi-wavelength observations. Using a combination of the Yohkoh Soft X-ray Telescope (SXT), Hard X-ray Telescope (HXT), Bragg Crystal Spectrometer (BCS) and the Transition Region and Coronal Explorer (TRACE), we find the source of the non-thermal broadenings, at their peak value, to be located in and above the SXR flare loops, not at the flare loop footpoints. After eliminating the footpoints as a potential source we discuss the likelihood that the source of non-thermally broadened emission lines is either evaporating chromospheric plasma or plasma above the Soft X-ray flare loop that is associated with the flare energy release.