First experimental evaluation of count-rate performance for micrometre resolution deep silicon detector.
Zihui Jin1, Rickard Brunskog1,2, Mats Danielsson1,2
1Department of Physics, KTH Royal Institute of Technology, Stockholm, Sweden.
Physics in Medicine and Biology
|January 11, 2024
Summary
A new ultra-fine-pitch deep silicon detector for photon-counting computed tomography (CT) shows promising count-rate performance. It maintains linearity up to 6.66 × 108 mm-2s-1, suitable for clinical CT applications.
Area of Science:
- Medical Imaging Physics
- Semiconductor Detector Technology
Background:
- Clinical photon-counting computed tomography (CT) requires detectors with high spatial resolution and excellent count-rate performance.
- Ultra-fine-pitch deep silicon detectors offer potential for micrometer spatial resolution, but their count-rate capabilities need experimental validation.
Purpose of the Study:
- To experimentally evaluate the count-rate performance of an ultra-fine-pitch deep silicon detector prototype designed for clinical photon-counting CT.
- To characterize the detector's response across a wide range of X-ray fluence rates.
Main Methods:
- A detector prototype with 14 × 650 μm2 pixels was tested using 35 keV monochromatic X-rays at the MAX IV synchrotron laboratory.
- Tungsten attenuators were used to achieve X-ray fluence rates ranging from 3.3 × 107 to 1.3 × 1011 mm-2s-1.
Main Results:
- The detector demonstrated count rate linearity up to 6.66 × 108 mm-2s-1 with 13% count loss.
- It remained functional at fluence rates as high as 2.9 × 1010 mm-2s-1.
- A semi-nonparalyzable dead-time model accurately described the data, yielding a dead time of 2.9 ns.
Conclusions:
- This study provides the first experimental count-rate performance data for a deep silicon detector with ultra-fine pixel geometry.
- The results indicate that this detector technology is suitable for the high fluence rates encountered in clinical CT, with minimal pile-up losses.
