In this research, cesium iodide (CsI) optical crystals have been grown for radiation detectors by homemade Bridgman-Stockbarger method. CsI crystals have been innovated for optical properties by applying techniques of Ca doping and multiple doping of Ca and Tl. As a reference; CsI:Tl crystal was also grown in the identical growth system. The crystal growth was processed under argon atmosphere in a quartz crucible. The composition of dopant was kept a constant of 0.35%wt. X-ray diffraction measurements show that CsI:Tl and CsI(Tl,Ca) crystals have the cubic crystal structure with a dominant (110) plane. But CsI:Ca crystal has two dominant planes of (110) and (211). In addition, photoluminescence (PL) measurements were performed to investigate their optical properties: CsI:Ca and CsI(Tl,Ca) crystals emitted the blue light in a range of 420-450 nm wavelength with two dominant peaks but the orange light emission of 590-nm wavelength from CsI:Tl crystal. To evaluate the efficiency and energy resolution of radiation detection by coupling these CsI scintillators with a photomultiplier tube, the results reveal their different radiation performances due to the main difference in their optical properties about the light emission characteristics. In conclusion, the radiation performance of CsI:Ca scintillator has been still challenge to accomplish with the optimized growth condition and the suitable coupling devices.