The Cd1-xMnxTe crystal is believed to be a good candidate to compete with Cd1-xMnxTe in the X-ray and γ-ray detector application. In this paper, Indium (In) doped Cd0.8Mn0.2Te (CdMnTe) ingots were grown by the modified Vertical Bridgman method. The as-grown crystals were characterized using Near-Infrared (NIR) transmission spectrum mapping of composition, X-ray double-crystal rocking curve measurement, I-V measurement and 241Am gamma rays radiation measurement. The Mn composition extracted from the NIR spectra at different axial and radial distances of the 30×40×2 mm3 CdMnTe wafers shown that the Mn concentration in the range of 0.19430.0008 to 0.2020.0025 mole fraction. The FWHM values of the X-ray rocking curves are of 40-80 arc sec, indicating a high crystalline perfection. The resistivity of the wafers is (2-3) ×1010Ω.cm. The CdMnTe planar detector irradiated by 241Am source shows the energy resolution of 8.5%.