Advances in High-Energy-Resolution CdZnTe Linear Array Pixel Detectors with Fast and Low Noise Readout Electronics

Area of Science:

• Materials Science
• Nuclear Instrumentation
• Photon Detection

Background:

• Cadmium Zinc Telluride (CZT) detectors offer high efficiency and room temperature operation for various applications.
• Current CZT detector limitations in spatial and energy resolution, especially at low energies (<10 keV), hinder their full potential in energy-resolved photon counting (ERPC).
• A lack of dedicated front-end electronics contributes to suboptimal spectroscopic performance in existing CZT systems.

Purpose of the Study:

• To present enhanced energy resolution results for CZT detectors utilizing novel front-end electronics.
• To demonstrate the capabilities of a new charge-sensitive amplifier, SIRIO, integrated with a pixelated CZT detector.
• To advance the development of energy-resolved X-ray scanners for material recycling, medical imaging, and food industry non-destructive testing.

Main Methods:

• Utilized a linear-array pixel detector made from boron oxide encapsulated vertical Bridgman-grown B-VB CZT crystals.
• Employed the SIRIO fast, low-noise charge-sensitive amplifier with the CZT detector (0.25-mm pitch, 1-mm thickness, -700-V bias).
• Measured detector performance using test pulsers and radioactive sources (²⁴¹Am, ⁵⁷Co) at room temperature (+20 °C) with varying peaking times.

Main Results:

• Achieved an equivalent noise charge of 39.2 el. r.m.s. (412 eV FWHM) at a 32 ns peaking time.
• Demonstrated a raw energy resolution of 1.3% (782 eV FWHM) at 59 keV (²⁴¹Am) with a 32 ns peaking time, improving the state-of-the-art for CZT.
• Attained an optimum resolution of 0.97% (576 eV FWHM) at 1 µs peaking time and 0.96% (1.17 keV) at 122 keV (⁵⁷Co) with a 1 µs peaking time.

Conclusions:

• The SIRIO amplifier significantly enhances the spectroscopic performance of CZT detectors, particularly at short peaking times.
• The developed CZT detector system shows great promise for high-resolution, energy-resolved X-ray applications.
• These advancements are crucial for developing next-generation X-ray scanners in diverse industrial and medical fields.