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研究X光能量散佈能譜儀之矽偵測器製作與特性探討
Thesis

研究X光能量散佈能譜儀之矽偵測器製作與特性探討

馬裕超
Masters, 國立清華大學, 工程與系統科學系
2016

Abstract

矽漂移偵測器 silicon drift detector
This research is aim to fabricate high energy resolution N-JFET silicon drift detector used in energy dispersive x-ray spectrometer to detect characteristic X-ray of material for composition information of selected region of material. N-JFET silicon drift detector integrates FET into detector chip, which makes shorter path of signal, and decrease thermal noise for cooling with chip simultaneously. Inner leakage current can be decreased with guard ring and enhance energy resolution and quantum efficiency of low energy X-ray with shallow implanted structure; in addition, larger window area leads to thinner dead layer, which can detect lower energy to improve performance of detector. We have detected characteristic peak of 241Am(5.468 MeV), and verified α particle by calculating stopping power of α particle with different distance in air. However, we have not detected characteristic peak of 55Fe(5.898 keV) because of overhigh noise. There are two possible reason for above result; first, the signal of 55Fe(5.898 keV) is 920 times smaller than 241Am(5.468 MeV). Second, polluted surface of detector causes increase of leakage current with higher bias. Those reasons could make 55Fe(5.898 keV) covered under noise. If contamination problem can be solved with vacuum package, detecting characteristic peak of 55Fe(5.898 keV) is possible.

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