The Speedster-EXD- A New Event-Driven Hybrid CMOS X-ray Detector

TL;DR

The Speedster-EXD is a fast, event-driven hybrid CMOS X-ray detector with advanced in-pixel features, achieving high energy resolution and minimal interpixel crosstalk, suitable for rapid X-ray imaging applications.

Contribution

This paper introduces the Speedster-EXD, a novel hybrid CMOS X-ray detector with in-pixel event-driven readout and noise reduction features, improving speed and energy resolution over previous designs.

Findings

Achieved 206 eV energy resolution at 5.89 keV

Measured interpixel crosstalk of 0.25%

Demonstrated stable gain variation of 0.80%

Abstract

The Speedster-EXD is a new 64x64 pixel, 40 $\mu$m pixel pitch, 100 $\mu$m depletion depth hybrid CMOS X-ray detector (HCD) with the capability of reading out only those pixels containing event charge, thus enabling fast effective frame rates. A global charge threshold can be specified, and pixels containing charge above this threshold are flagged and read out. The Speedster detector has also been designed with other advanced in-pixel features to improve performance, including a low-noise, high-gain CTIA amplifier that eliminates interpixel capacitance crosstalk (IPC), and in-pixel Correlated Double Sampling (CDS) subtraction to reduce reset noise. We measure the best energy resolution on the Speedster-EXD detector to be 206 eV (3.5 %) at 5.89 keV and 172 eV (10.0 %) at 1.49 keV. The average IPC to the four adjacent pixels is measured to be 0.25 $\pm$ 0.2 % (i.e. consistent with zero). The pixel-to-pixel gain variation is measured to be 0.80 $\pm$ 0.03 %, and a Monte Carlo simulation is applied to better characterize the contributions to the energy resolution.