基于SiPM读出的塑料闪烁体探测器时间性能研究

研究了基于硅光电倍增管(SiPM)双端读出的面积为10 cm ×10 cm的薄塑料闪烁体探测器的时间性能。239Pu放射源测试结果显示:(1)在多支SiPM串连读出方式下，随着SiPM数量的增加，探测器时间分辨逐渐变好；(2)在固定12支SiPM数量不变的情况下，并联支路越多，探测器时间分辨越差；(3)采用快时间塑料闪烁体并增加其厚度，可有效提高探测器时间分辨；(4)采用比束斑尺寸更大的塑料闪烁体，可有效提高探测器时间分辨的位置均匀性；(5)对于1 mm厚的EJ232塑料闪烁体探测器，在单端12支SiPM串行连接的情况下，可获得好于131 ps的时间分辨。这一研究对RIBLL2起始时间探测器的升级改造具有重要的指导意义。     

Fragmentation of stable and neutron-rich 12-16C into boron fragments at approximately 240 MeV/nucleon

The elemental fragmentation cross sections of boron fragments produced by stable and neutron-rich^12-16C beams with a carbon target were systematically measured at an incident beam energy of approximately 240 MeV/nucleon.The measured cross sections were found to increase as the projectile mass number increases.The observed feature is explained qualitatively based on the abrasion-ablation two-stage reaction model and is compared quantitatively with predictions from various reaction models,including empirical and statistical models.All models agree with the measured cross sections within a factor of 2.