  We evaluate the performances of a 100 um-thick silicon strip detector (SSD)
with a 300 MeV proton beam and a 90Sr beta-ray source. Signals from the SSD
have been read out using a VLSI chip. Common-mode noise, signal separation
efficiency and energy resolution are compared with those for the SSD's with a
thickness of 300 um and 500 um. Energy resolution for minimum ionizing
particles (MIP's) is improved by fitting the non-constant component in a
common-mode noise with a linear function.
