Metal halide perovskites （MHPs） single crystals have potential applications in the field of radiation detection due to their excellent optoelectronic properties. Additionally， suppressing defects both in the bulk during single crystal growth and on the surface after growth is expected to further improve the performance of semiconductor radiation detectors. In this study， high-quality MAPbBr₃ single crystals with dimensions exceeding 10 mm×10 mm were grown by inverse temperature crystallization （ITC） using the amphiphilic surfactant thiobetaine 10 as an additive. The mechanism of additive-optimized crystal growth was analyzed and characterized. The synergistic effect of sulfonic acid amphiphiles in crystallization control and defect passivation significantly suppressed defect formation. The full width at half maximum （FWHM） of the grown MAPbBr₃ single crystals reduces from 0.071° to 0.046°， while the long-chained alkyl groups make the surface of the crystals exhibit excellent hydrophobicity， increasing the surface contact angle increases from 84.04° to 96.25°. These results demonstrate an overall improvement in MHP single crystal quality. A device with Ni/Au-Ni/Au ring-symmetric electrodes was prepared， and the device resistivity increases from 2.08×10⁷ Ω·cm to 2.82×10⁸ Ω·cm， with a carrier mobility lifetime product of 1.81×10^-2 cm²·V^-1. Furthermore， MAPbBr₃ single crystals detector achieve an X-ray detection sensitivity of 1 459 μC·Gy_air^-1·cm^-2 under 50 kV X-ray irradiation and maintain stable operation over a 1 000 s test period. This strategy advances the practical application of perovskite single crystals in X-ray detection. Moreover， our strategy contributes to further progress in the practical application of perovskite single crystals in the field of X-ray detection.