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 b roadenings in an M1.7 two-ribbon solar flare using multi-wavelength observa tions. Using a combination of the Yohkoh Soft X-ray Telescope (SXT), Hard X -ray Telescope (HXT), Bragg Crystal Spectrometer (BCS) and the Transition R egion and Coronal Explorer (TRACE), we find the source of the non-thermal b roadenings, at their peak value, to be located in and above the SXR flare l oops, not at the flare loop footpoints. After eliminating the footpoints as a potential source we discuss the likelihood that the source of non-therma lly broadened emission lines is either evaporating chromospheric plasma or plasma above the Soft X-ray flare loop that is associated with the flare en ergy release.