Hybrid Pixel Sensor Array for High-Speed X-Ray Detection

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Solution Overview

Problem

Current high-speed X-ray detection technologies face challenges in achieving high dynamic range and radiation hardness, particularly in ultra-short X-ray applications like the European XFEL, where existing hybrid sensor designs are complex and not optimized for X-ray imaging.

Innovation Solution

A hybrid pixel sensor array combining a sensor tile with a charge-coupled device (CCD) array and active CMOS circuitry, where the sensor tile is bonded to a readout ASIC using Indium bump-bonding, featuring a GaAs sensor for improved radiation hardness and high stopping power, allowing for efficient X-ray detection with a pitch as low as 60 microns.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If existing hybrid sensor designs (CdZnTe bonded to ASIC) are used for high-speed X-ray detection, then detection capability is achieved, but device complexity and lack of optimization for ultra-short X-ray pulses occur

Engineering Contradiction:
ImproveX-ray detection speedVSAvoidsensor structure complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The patent combines a GaAs sensor array with a CMOS readout integrated circuit (ROIC) into a single hybrid pixel detector chip. The sensor and readout electronics are integrally coupled, eliminating the need for separate bonding of detector and electronics, thus reducing device complexity while maintaining high detection speed capability for ultra-short X-ray pulses

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The hybrid pixel detector is designed to handle multiple detection modes (photon counting and analog integration) and is optimized for ultra-short pulse detection. The same detector structure can operate in different modes depending on the application, providing universal functionality for various X-ray imaging requirements without needing separate specialized detectors

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If existing hybrid sensor designs are used, then basic detection is achieved, but radiation hardness and stopping power are insufficient for high-energy X-rays

Engineering Contradiction:
Improveradiation hardnessVSAvoidsensor material complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent changes the material parameter from CdZnTe to GaAs (gallium arsenide). GaAs has superior radiation hardness and higher stopping power for high-energy X-rays compared to traditional materials. This material substitution directly improves reliability for high-energy X-ray detection without requiring complex structural modifications

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The hybrid detector uses a composite structure combining GaAs semiconductor material with CMOS electronics. This composite design leverages the radiation hardness of GaAs while integrating the readout capabilities of CMOS technology, achieving both improved reliability and functional completeness

Inventive Principle:
Principle #40Composite materials

3Adaptability or versatility

If custom ASICs with complex readout circuits are used for high dynamic range, then detection range is improved, but device complexity increases

Engineering Contradiction:
Improvedynamic rangeVSAvoidreadout circuit complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent implements a dynamic readout capability where the detector can switch between photon counting mode and analog integration mode. The readout circuit includes dynamic elements such as reset switches and integration capacitors that can be configured based on the detection requirements, providing adaptability for high dynamic range while maintaining manageable complexity through controlled configurability

Inventive Principle:
Principle #15Dynamics

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The hybrid pixel sensor array enhances X-ray detection speed and radiation hardness, enabling efficient high-energy X-ray imaging with improved counting efficiency and room temperature operation, suitable for ultra-short X-ray pulses at facilities like the European XFEL.

Implementation Method 1

a sensor for generating an imaging (detection) signal

Methodology Applied
Scientific EffectPhotoelectric effect: Photoelectric Effect

Implementation Method 2

a charge-coupled device (CCD) array, coupled to the sensor so as to receive samples from the imaging signal and configured for storage of a plurality of samples

Methodology Applied
Scientific EffectCharge coupling:

Implementation Method 3

the sensor tile is bonded to a readout ASIC using Indium bump-bonding

Methodology Applied
Scientific EffectIndium bump-bonding:

Data Source

PatentEP3075145B1Hybrid pixel sensor array
Publication Date: 2020.02.12 UNITED KINGDOM RESEARCH AND INNOVATION
  • EP3075145B1 patent drawingFigure 1
  • EP3075145B1 patent drawingFigure 2
  • EP3075145B1 patent drawingFigure 3

AI summary

A hybrid pixel sensor array is provided. Each pixel of the array comprises: a sensor for generating an imaging signal; a Charged-Coupled Device (CCD) array, coupled to the sensor so as to receive samples from the imaging signal and configured for storage of a plurality of samples; and active CMOS circuitry, coupled to the CCD array for generating a pixel output signal from the stored samples. The sensors of the pixels are part of a sensor portion of the hybrid pixel sensor array that is separate from both the CCD array and active CMOS circuitry of the pixels.