Background：The lower measure limit of radiation pulse detection is usually about hundred-μA lever due to various kinds of noise existed in electronic system. However

some detectors could get the small pulse signal at the lever of decade nA and keep the noise at the lever of nA. Therefore

the conventional detection system would not collect these weak signals. Purpose: This study aims to design and implement a radiation detection system to overcome lower limitation of detection and improve the linearity of measurement for large dynamic pulse signals. Methods: The detection system noise was analyzed to explore the lower measure limit in a wide system bandwidth range. Based on the design of low noise amplifier circuit and highly dynamic digital transmission system

it could confirm the low measure limit through the theories of a small capacitor’s output is in a linear correlation with input. Improvement was made according to experimental testing. Results: The system could process the weak pulse signals in the range of 0.8–680μA (peak) with 20MHz bandwidth. A γ-radiation pulse signal below 1μA with the LSO (Lu2SiO5)+PMT (photo multiplier tube) radiation detector was successfully obtained by experiment. Conclusion: The new radiation detection system constituted with low-noise broad-band amplifier and highly dynamic digital transmission system was useful in expanding the system measure range to improve the system detection efficiency. Abstract