  Solar observations in the mid-infrared 8-14 \mu\m band continuum were carried
out with cadence of 5 frames per second, in December 2007. Rapid small heated
sources, with typical duration of the order of seconds, were found on the
bright plage-like areas around sunspots, in association with relatively weak
GOES soft X-ray bursts. This work presents the analysis of fast mid-infrared
flashes detected during a GOES B2.0-class event on 10 December 2007, beginning
at about 10:40 UT. Rapid brightness temperature enhancements of 0.5 to 2.0 K
were detected at the Earth by a microbolometer array, using a telescope with
10.5 cm diameter aperture producing a diffraction limited field-of-view of 25
arcsec. Minimum detectable temperature change was of 0.1 K. The corresponding
fluxes are 30-130 solar flux units. At the solar surface the estimated rapid
brightenings were of 50-150 K
