Simulation of 1.5-mm-thick and 15-cm-diameter gated silicon drift X-ray detector operated with a single high-voltage source

Abstract

High-resolution silicon X-ray detectors with a large active area are required for effectively detecting traces of hazardous elements in food and soil through the measurement of the energies and counts of X-ray fluorescence photons radially emitted from these elements. The thicknesses and areas of commercial silicon drift detectors (SDDs) are up to 0.5 mm and 1.5 cm 2 , respectively. We describe 1.5-mm-thick gated SDDs (GSDDs) that can detect photons with energies up to 50 keV. We simulated the electric potential distributions in GSDDs with a Si thickness of 1.5 mm and areas from 0.18 to 168 cm 2 at a single high reverse bias. The area of a GSDD could be enlarged simply by increasing all the gate widths by the same multiple, and the capacitance of the GSDD remained small and its X-ray count rate remained high.

Gated Silicon Drift Detector Fabricated from a Low-Cost Silicon Wafer

“…GSDDs have a cathode and only one p-ring, and to which the same reverse bias can be applied. Figure 1 shows half of a schematic cross section of a cylindrical GSDD with seven ring-shaped gates and one p-ring that does not contain MOSFETs or implanted resistors [ 37 , 38 , 40 – 43 ].…”

“…To fabricate low-cost X-ray detectors, we have designed several simple-structure SDDs without MOSFETs or implanted resistors [ 33 – 43 ], one of which is a gated silicon drift detector (GSDD) [ 37 , 38 , 40 – 43 ]. In GSDDs fabricated by using a 0.625-mm-thick n − Si substrate with a resistivity (ρ Si ) of 10 kΩ·cm, an energy resolution of 145 eV at 5.9 keV was obtained from a 55 Fe source at −38 °C [ 41 ].…”

Optical and scintillation properties of Lumilass-G and -R glasses

“…Such sensors are called ionizing radiation detectors. Most ionizing radiation detectors are solid-state detectors, and they are mainly divided into two groups such as semiconductor detectors (Si, 1) Ge, 2) CdTe, 3) and TlBr 4) ) and luminescence-based detectors. Luminescence-based detectors are also classified into two types, including scintillation detectors 5) and dosimeters with storage phosphors by optically stimulated luminescence (OSL), 6) thermally stimulated luminescence (TSL), 7) and radiophotoluminescence (RPL) 8) phenomena.…”