Characterization of CdTe Sensors with Schottky Contacts Coupled to Charge-Integrating Pixel Array Detectors for X-Ray Science

TL;DR

This paper characterizes CdTe sensors with Schottky contacts coupled to charge-integrating pixel array detectors, demonstrating their high dynamic range and fast framing capabilities for X-ray imaging applications.

Contribution

It presents the first detailed characterization of CdTe sensors with Schottky contacts integrated with two advanced charge-integrating PADs, highlighting their performance advantages.

Findings

High dynamic range from single-photon to tens of millions of x-rays per pixel.

Fast framing at 1 kHz with in-pixel storage and overflow circuitry.

Effective coupling of CdTe sensors with charge-integrating PADs for X-ray science.

Abstract

Pixel Array Detectors (PADs) consist of an x-ray sensor layer bonded pixel-by-pixel to an underlying readout chip. This approach allows both the sensor and the custom pixel electronics to be tailored independently to best match the x-ray imaging requirements. Here we present characterizations of CdTe sensors hybridized with two different charge-integrating readout chips, the Keck PAD and the Mixed-Mode PAD (MM-PAD), both developed previously in our laboratory. The charge-integrating architecture of each of these PADs extends the instantaneous counting rate by many orders of magnitude beyond that obtainable with photon counting architectures. The Keck PAD chip consists of rapid, 8-frame, in-pixel storage elements with framing periods $<$150 ns. The second detector, the MM-PAD, has an extended dynamic range by utilizing an in-pixel overflow counter coupled with charge removal circuitry activated at each overflow. This allows the recording of signals from the single-photon level to tens of millions of x-rays/pixel/frame while framing at 1 kHz. Both detector chips consist of a 128$\times$128 pixel array with (150 $\mu$m)$^2$ pixels.