Simulating 50 keV X-ray Photon Detection in Silicon with a Down-Conversion Layer

• Published in: Sensors (Basel, Switzerland) Vol. 21; no. 22; p. 7566
• Main Authors: Anagnost, Kaitlin M., Lee, Eldred, Wang, Zhehui, Liu, Jifeng, Fossum, Eric R.
• Format: Journal Article
• Language: English
• Published: Basel MDPI AG 14.11.2021; MDPI
• Subjects: Absorption; Atoms & subatomic particles; Design; direct detection; Efficiency; Energy; Holes (electron deficiencies); image sensor; indirect detection; Photoelectrons; Photons; Radiation; Scintillation counters; scintillator; Sensors; Silicon; Simulation; Spatial resolution; Standard deviation; Thickness; X-ray detection; X-rays
• ISSN: 1424-8220; 1424-8220
• DOI: 10.3390/s21227566

Simulation results are presented that explore an innovative, new design for X-ray detection in the 20–50 keV range that is an alternative to traditional direct and indirect detection methods. Typical indirect detection using a scintillator must trade-off between absorption efficiency and spatial resolution. With a high-Z layer that down-converts incident photons on top of a silicon detector, this design has increased absorption efficiency without sacrificing spatial resolution. Simulation results elucidate the relationship between the thickness of each layer and the number of photoelectrons generated. Further, the physics behind the production of electron-hole pairs in the silicon layer is studied via a second model to shed more light on the detector’s functionality. Together, the two models provide a greater understanding of this detector and reveal the potential of this novel form of X-ray detection.