Study of Radiation Damage of Silicon Mecrostrip Detectors

表面辐射损伤对硅微带探测器最严重的影响是在硅体和覆盖探测器的氧化硅界面上积聚正电荷。正电荷导致微放电。我们研制了一种针对微放电的硅微带探测器。实现该探测器的要点是1)使读出条比注入条更窄，2)对比以前更深的条注入杂质。对体损伤，测量了体型反转后全耗尽电压的增加、带间隔离度的降低和电荷收集效率。首次讨论了这些效应之间的关系。本研究完成了硅微带探测器辐射损伤的基础性研究，对于制作抗辐射的硅微带探测器，1)减小微放电，2)防止增加全耗尽电压，3)允许高偏置电压是必不可少的。这种耐辐射的硅微带探测器是通过辐照、脉冲激光和光束测试来制造和测试的。我们确认，高达1MRad的辐射探测器仍然活着。这些结果被应用于我们在费米国家加速器实验室合作建造的顶点探测器SVXII的硅微带探测器的生产中。欧洲核子研究中心ATLAS探测器的跟踪探测器SCT也将考虑到我们的结果而开发。

The most serious effect of the surface radiation damage on silicon microstrip detectors is accumulation of positive charge on the interface of a silicon bulk and silicon oxide which covers the detectors. The positive charge causes the microdischarge. We developed a silicon microstrip detector which is against to the microdischarge. Important points to realize this detector are 1) to make readout strips narrower than implant strips and 2) to implant impurities for strips deeper than before. For the bulk damage, the bulk-type inversion followed by an increase of the full depletion voltage, reduction of interstrip isolation and charge collection efficiency were measured. The relation between these effects was discussed for the first time. This study finishes the fundamental study of radiation damage of the silicon microstrip detector.For fabrication of radiation-hard silicon microstrip detectors, 1) reduction of the micro-discharge, 2) prevention of increasing the full depletion voltage and 3) allowance for the high bias voltage are essential. Such radiation-hard silicon microstrip detectors were produced and tested by irradiation, a pulsed laser and beam tests. We confirm that irradiated detectors up to 1MRad were still alive. These results are applied for production of the silicon microstrip detectors of the vertex detector SVXII which our collaboration are building at Fermi National Accelerator Laboratory. The tracking detector SCT of the ATLAS detector at CERN will also be developed by taking our results into account.