CGRO/OSSE observations of the Cassiopeia A SNR

. We present all OSSE observations to date of the Cas A supernova remnant. The objectives are to detect the 44 Ti lines, one of which has been reportedly detected by COMPTEL, and the hard X-ray continuum above 40 keV, as indicated by HEAO-A2 measurements. Our best fit flux in each of three 44 Ti lines is (+1.76 \Sigma 1:51 1:48 ) \Theta 10 \Gamma5 fl cm \Gamma2 s \Gamma1 with Ø 2 = 1.01, d.o.f.=1780. The implied 44 Ti mass of ¸10 \Gamma4 M fi is compatible with explosive nucleosynthesis calculations. OSSE detected also a continuum below 200 keV at better than 4oe confidence level with a flux of ¸9 \Theta 10 \Gamma4 fl cm \Gamma2 s \Gamma1 MeV \Gamma1 at 100 keV. This continuum can be fitted equally well with a power law, an exponential, or a thermal bremsstrahlung model. The implied temperature of kT ß35 keV can be interpreted as the emission from the shocked circumstellar matter (CSM) by the primary blastwave of the supernova. Alternatively, the continuum ca..