Effect of bias conditions on transient anode current for quasi-double-sided silicon drift detector with high energy resolution

Silicon drift detectors (SDDs) are widely applied for x-ray detection due to their remarkable energy resolution. The main contribution to energy resolution is the electrical noise of the measurement system. In addition, imperfect charge collection and ballistic deficits also deteriorate the energy resolution, which is closely related to bias conditions. However, bias condition's effect on energy resolution has been rarely reported. To investigate its effect on energy resolution, we proposed a quasi-double-sided silicon drift detector (QD-SDD) with a drift ring structure designed on the back side. QD-SDDs was simulated and verified to have more flexibility in bias conditions, achieving better electron collection efficiency and shorter collection time at higher bias voltages. Finally, the fabricated QD-SDDs were characterized using a55Fe radioactive source. The experimental results show that the energy resolution of the QD-SDD varies with different bias conditions. The optimal energy resolution is 170 eV under the optimized bias conditions.