X-ray imaging camera using INTPIX4NA SOIPIX detector with SiTCP-XG 10GbE based high-speed readout system

TL;DR

This work presents an X-ray camera built around the INTPIX4NA SOIPIX detector, integrated with the PF-DAQSIX 10 Gbps readout and a Peltier-cooled chamber to enable stable long-exposure imaging at low X-ray intensities. The system achieves a photon-peak energy resolution of $R = 36.23\%$ at $12~\mathrm{keV}$ and an ENC per pixel of about $61~e^-$, with a Nyquist frequency of $f_N = 29.4~\mathrm{cycle/mm}$ and MTF$>65\%$ in both directions, while low-intensity imaging at $14.4~\mathrm{keV}$ with two Fresnel zone plates shows superior contrast compared to a room-temperature sCMOS. The results validate the detector's suitability for 5–20 keV imaging under low-intensity, low-contrast conditions (e.g., soft tissues, fine structures, radiation-sensitive specimens) and highlight its potential for high-resolution X-ray microscopy using dual-FZP optics with reduced dose. The authors foresee integrating the camera into practical high-resolution X-ray imaging workflows and extending applications to low-brightness or low-contrast samples where photon-budget is critical.

Abstract

The silicon-on-insulator pixel (SOIPIX) detector is a unique monolithic-structure imaging device currently being developed by the SOIPIX group led by the High Energy Accelerator Research Organization (KEK). The detector team at KEK Photon Factory (PF) is also developing an X-ray camera using INTPIX4NA with a 14.1 $\times$ 8.7 $\mathsf{mm^2}$ sensitive area and 425,984 (832 column $\times$ 512 row matrix) pixels, with a pixel size of 17 $\times$ 17 $\mathsf{μm^2}$. The detector has high resolution and sensitivity for low-intensity X-rays, making it suitable for imaging in optical systems with lower X-ray intensities, such as an X-ray zooming microscope using two Fresnel zone plates (FZPs), which is also under development at PF. To enable imaging under such conditions, we developed a detector cooling system using a Peltier element to support longer exposure time (~0.5 seconds per frame). Additionally, we developed a new readout system using DAQ boards developed by PF, equipped with SiTCP-XG (network controller implemented on field-programmable gate array) that supports 10 Gbps Ethernet for high-frame-rate imaging at several hundred hertz. The new X-ray camera was tested at the PF BL-14A, BL-14B, and AR-NE1A experimental stations, and the resolution and sensitivity characteristics were confirmed. Given these confirmed characteristics, this X-ray camera is suitable for X-ray imaging using 5--20 keV X-rays under low-intensity, low-contrast conditions. These conditions are ideal for capturing soft tissues with poor contrast, objects with fine structures, and specimens vulnerable to radiation damage.

Figures (13)

• Figure 1: Structure of SOIPIX detector.
• Figure 2: Photograph of INTPIX4NA from circuit layer side.
• Figure 3: Photograph of INTPIX4NA implemented on PCB.
• Figure 4: Schematic of PF-DAQSIX system with Peltier detector cooling system.
• Figure 5: Photograph of the main readout boards of PF-DAQSIX system (upper right shows the corresponding part in the schematic).