Characterisation of a soft X-ray optimised CMOS Image Sensor

Heymes, Julian; Ivory, James; Stefanov, Konstantin D.; Buggey, Thomas W.; Hetherington, Oliver; Soman, Matthew R.; Holland, Andrew D.

doi:10.1088/1748-0221/17/05/p05003

Cited by 11 publications

(7 citation statements)

References 11 publications

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“…This kind of detector belongs to the family of monolithic active pixels, developed primarily for imaging and high-density, high-resolution radiation detection applications. Being a sort of “camera on chip”, active pixel sensors integrate the electronic amplifier and have shown high potential and to be beneficial in the applications for high resolution imaging [ 23 , 24 , 25 ] and for radiation particle tracking [ 26 , 27 , 28 , 29 , 30 ]. An attempt to adopt such CMOS imaging devices for dosimetry has been proposed previously by [ 31 ] and also by [ 32 ].…”

Section: Introductionmentioning

confidence: 99%

Preliminary Characterization of an Active CMOS Pad Detector for Tracking and Dosimetry in HDR Brachytherapy

Bui,

Large,

Poder

et al. 2024

Sensors

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We assessed the accuracy of a prototype radiation detector with a built in CMOS amplifier for use in dosimetry for high dose rate brachytherapy. The detectors were fabricated on two substrates of epitaxial high resistivity silicon. The radiation detection performance of prototypes has been tested by ion beam induced charge (IBIC) microscopy using a 5.5 MeV alpha particle microbeam. We also carried out the HDR Ir-192 radiation source tracking at different depths and angular dose dependence in a water equivalent phantom. The detectors show sensitivities spanning from (5.8 ± 0.021) × 10−8 to (3.6 ± 0.14) × 10−8 nC Gy−1 mCi−1 mm−2. The depth variation of the dose is within 5% with that calculated by TG-43. Higher discrepancies are recorded for 2 mm and 7 mm depths due to the scattering of secondary particles and the perturbation of the radiation field induced in the ceramic/golden package. Dwell positions and dwell time are reconstructed within ±1 mm and 20 ms, respectively. The prototype detectors provide an unprecedented sensitivity thanks to its monolithic amplification stage. Future investigation of this technology will include the optimisation of the packaging technique.

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Section: Introductionmentioning

confidence: 99%

Preliminary Characterization of an Active CMOS Pad Detector for Tracking and Dosimetry in HDR Brachytherapy

Bui,

Large,

Poder

et al. 2024

Sensors

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“…Hull et al (2019) reported that 148 eV at 5.9 keV can be reached for a hybrid CMOS sensor, by applying pixel-bypixel gain correction. At around −30°C, Heymes et al (2022) reached a resolution of 142 eV at 5.9 keV with a CIS221-X sensor, and a backside illuminated version of this sensor reached 153 eV at 5.9 keV at −40°C (Stefanov et al 2022).…”

Section: Introductionmentioning

confidence: 99%

Improving the X-Ray Energy Resolution of a Scientific CMOS Detector by Pixel-level Gain Correction

Wu¹,

Ling²,

Wang³

et al. 2023

PASP

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Scientific Complementary Metal Oxide Semiconductor (sCMOS) sensors are finding increasingly more applications in astronomical observations, thanks to their advantages over charge-coupled devices such as a higher readout frame rate, higher radiation tolerance, and higher working temperature. In this work, we investigate the performance at the individual pixel level of a large-format sCMOS sensor, GSENSE1516BSI, which has 4096 × 4096 pixels, each of 15 μm in size. To achieve this, three areas on the sCMOS sensor, each consisting of 99 × 99 pixels, are chosen for the experiment. The readout noise, conversion gain and energy resolutions of the individual pixels in these areas are measured from a large number (more than 25,000) of X-ray events accumulated for each of the pixels through long time exposures. The energy resolution of these pixels can reach 140 eV at 6.4 keV at room temperature and shows a significant positive correlation with the readout noise. The accurate gain can also be derived individually for each of the pixels from its X-ray spectrum obtained. Variations of the gain values are found at a level of 0.56% statistically among the 30 thousand pixels in the areas studied. With the gain of each pixel determined accurately, a precise gain correction is performed pixel by pixel in these areas, in contrast to the standardized ensemble gain used in the conventional method. In this way, we could almost completely eliminate the degradation of energy resolutions caused by gain variations among pixels. As a result, the energy resolution at room temperature can be significantly improved to 124.6 eV at 4.5 keV and 140.7 eV at 6.4 keV. This pixel-by-pixel gain correction method can be applied to all kinds of CMOS sensors, and is expected to find interesting applications in X-ray spectroscopic observations in the future.

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“…However, in recent years, the performance of sCMOS sensors has been significantly improved, boasting faster readout speeds, superior irradiation resistance, and more flexible operating temperatures compared to traditional CCDs. Therefore, several X-ray space missions, such as Lobster Eye Imager for Astronomy (LEIA; Zhang et al 2022;Ling 2023), Einstein Probe (EP; Yuan et al 2018Yuan et al , 2022, and THESEUS (concept) (Heymes et al 2020(Heymes et al , 2022Stefanov et al 2022), used or will use sCMOS sensors as focal plane detectors.…”

Section: Introductionmentioning

confidence: 99%

An Aluminum-coated sCMOS Sensor for X-Ray Astronomy

Wu,

Ling,

Zhang

et al. 2023

PASP

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In recent years, tremendous progress has been made on scientific Complementary Metal Oxide Semiconductor (sCMOS) sensors, making them a promising device for future space X-ray missions. We have customized a large-format sCMOS sensor, G1516BI, dedicated for X-ray applications. In this work, a 200 nm thick aluminum layer is successfully sputtered on the surface of this sensor. This Al-coated sensor, named EP4K, shows consistent performance with the uncoated version. The readout noise of the EP4K sensor is around 2.5 e− and the dark current is less than 0.01 e− pixel−1 s−1 at −30°C. The maximum frame rate is 20 Hz in the current design. The ratio of single pixel events of the sensor is 45.0%. The energy resolution can reach 153.2 eV at 4.51 keV and 174.2 eV at 5.90 keV at −30°C. The optical transmittance of the aluminum layer is approximately 10−8 to 10−10 for optical lights from 365 to 880 nm, corresponding to an effective aluminum thickness of around 140 to 160 nm. The good X-ray performance and low optical transmittance of this Al-coated sCMOS sensor make it a good choice for space X-ray missions. The Lobster Eye Imager for Astronomy, which has been working in orbit for about one year, is equipped with four EP4K sensors. Furthermore, 48 EP4K sensors are used on the Wide-field X-ray Telescope on the Einstein Probe satellite, which will be launched at the end of 2023.

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Characterisation of a soft X-ray optimised CMOS Image Sensor

Cited by 11 publications

References 11 publications

Preliminary Characterization of an Active CMOS Pad Detector for Tracking and Dosimetry in HDR Brachytherapy

Preliminary Characterization of an Active CMOS Pad Detector for Tracking and Dosimetry in HDR Brachytherapy

Improving the X-Ray Energy Resolution of a Scientific CMOS Detector by Pixel-level Gain Correction

An Aluminum-coated sCMOS Sensor for X-Ray Astronomy

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