Changes of the average brightness and non-uniformity of dark output images,and quality of pictures captured under natural lighting for the color CMOS digital image sensorsirradiated at different electron doses have be...Changes of the average brightness and non-uniformity of dark output images,and quality of pictures captured under natural lighting for the color CMOS digital image sensorsirradiated at different electron doses have been studied in comparison to those from theγ-irradiated sensors. For the electron-irradiated sensors, the non-uniformity increases obviouslyand a small bright region on the dark image appears at the dose of 0.4 kGy. The average brightnessincreases at 0.4 kGy, increases sharply at 0.5 kGy. The picture is very blurry only at 0.6 kGy,showing the sensor undergoes severe performance degradation. Electron radiation damage is much moresevere than γ radiation damage for the CMOS image sensors. A possible explanation is presented inthis paper.展开更多
In this study, we fabricated a sapphire based fiber-optic radiation sensor. To evaluate the fiber- optic radiation sensor, we measured the spectrum and intensity of the luminescence generated from the fiber-optic radi...In this study, we fabricated a sapphire based fiber-optic radiation sensor. To evaluate the fiber- optic radiation sensor, we measured the spectrum and intensity of the luminescence generated from the fiber-optic radiation sensor according to the thickness of the PMMA block by irradiation of gamma rays emitted from a Co-60 source. And the result was compared with the value calculated from the formula of Lambert-Beer.展开更多
The quality of dark output images from the CMOS (complementarymetal oxide semiconductor) black and white (B & W) digital imagesensors captured before and after γ-ray irradiation was studied. Thecharacteristic par...The quality of dark output images from the CMOS (complementarymetal oxide semiconductor) black and white (B & W) digital imagesensors captured before and after γ-ray irradiation was studied. Thecharacteristic parameters of the dark output images captured atdifferent radiation dose, e.g. average brightness and itsnon-uniformity of dark out- put images, were analyzed by our testsoftware. The primary explanation for the change of the parameterswith the radi- ation dose was given.展开更多
The objective of this work is to analyze the transient effects of ^60Co gamma rays in the CMOS image sensor (CIS) using the Monte Carlo method, based on Geant4. The track, energy spectrum, and angle of produced electr...The objective of this work is to analyze the transient effects of ^60Co gamma rays in the CMOS image sensor (CIS) using the Monte Carlo method, based on Geant4. The track, energy spectrum, and angle of produced electrons when gamma rays traversed a silicon or silicon dioxide cube were calculated. A simplified model of a 500 × 500 CIS array was established, and the transient effects of gamma rays in the CIS were simulated. The raw images were captured when the CIS was irradiated by gamma rays. The experimental results were compared with the simulation results. The characteristics of the typical events induced by transient effects were analyzed.展开更多
The CMOS (Complementary Metal Oxide Semiconductor) image sensor of a smartphone has been known for its sensitivity to gamma-rays. In this research, some smartphones were selected and tested for measurement of gamma-ra...The CMOS (Complementary Metal Oxide Semiconductor) image sensor of a smartphone has been known for its sensitivity to gamma-rays. In this research, some smartphones were selected and tested for measurement of gamma-rays emitted from Cesium-137 and Iridium-192 sources. During measurements, the phones were set in video mode while the camera lenses were covered with black adhesive tape to prevent light exposure. Interaction of gamma-rays with the CMOS appeared as flashing bright spots on the image. The bright spots were then counted by using the freely available ImageJ software. Preliminary results indicated that the number of bright spots increased linearly with increase of gamma-ray dose rate. An in-house Android application software was then developed for real-time counting of the bright spots. The application software also allowed users to input a calibration equation so that the phones could simultaneously convert the count rate to display in dose rate. This research demonstrated that, after appropriate calibration, smartphones could be used as gamma-ray measuring devices for radiation safety control involving high activity sources such as in industrial radiography, gamma-ray irradiation facility and medical treatment.展开更多
基金This project is financially supported by the Narional Natural Science Foundation of China(Nos 10375034 and 10075029) and the Basic Research Foundation of Tsinghua University (No. JC2002058).
文摘Changes of the average brightness and non-uniformity of dark output images,and quality of pictures captured under natural lighting for the color CMOS digital image sensorsirradiated at different electron doses have been studied in comparison to those from theγ-irradiated sensors. For the electron-irradiated sensors, the non-uniformity increases obviouslyand a small bright region on the dark image appears at the dose of 0.4 kGy. The average brightnessincreases at 0.4 kGy, increases sharply at 0.5 kGy. The picture is very blurry only at 0.6 kGy,showing the sensor undergoes severe performance degradation. Electron radiation damage is much moresevere than γ radiation damage for the CMOS image sensors. A possible explanation is presented inthis paper.
文摘In this study, we fabricated a sapphire based fiber-optic radiation sensor. To evaluate the fiber- optic radiation sensor, we measured the spectrum and intensity of the luminescence generated from the fiber-optic radiation sensor according to the thickness of the PMMA block by irradiation of gamma rays emitted from a Co-60 source. And the result was compared with the value calculated from the formula of Lambert-Beer.
基金the National Natural Science Foundation of China (No.10075029).
文摘The quality of dark output images from the CMOS (complementarymetal oxide semiconductor) black and white (B & W) digital imagesensors captured before and after γ-ray irradiation was studied. Thecharacteristic parameters of the dark output images captured atdifferent radiation dose, e.g. average brightness and itsnon-uniformity of dark out- put images, were analyzed by our testsoftware. The primary explanation for the change of the parameterswith the radi- ation dose was given.
基金supported by the National Natural Science Foundation of China(Nos.11805155,11875223,and 11690043)the Chinese Academy of Sciences strategic pilot science and technology project(No.XDA15015000)+1 种基金the Innovation Foundation of Radiation Application(No.KFZC2018040201)the Foundation of State Key Laboratory of China(Nos.SKLIPR1803 and 1610)
文摘The objective of this work is to analyze the transient effects of ^60Co gamma rays in the CMOS image sensor (CIS) using the Monte Carlo method, based on Geant4. The track, energy spectrum, and angle of produced electrons when gamma rays traversed a silicon or silicon dioxide cube were calculated. A simplified model of a 500 × 500 CIS array was established, and the transient effects of gamma rays in the CIS were simulated. The raw images were captured when the CIS was irradiated by gamma rays. The experimental results were compared with the simulation results. The characteristics of the typical events induced by transient effects were analyzed.
文摘The CMOS (Complementary Metal Oxide Semiconductor) image sensor of a smartphone has been known for its sensitivity to gamma-rays. In this research, some smartphones were selected and tested for measurement of gamma-rays emitted from Cesium-137 and Iridium-192 sources. During measurements, the phones were set in video mode while the camera lenses were covered with black adhesive tape to prevent light exposure. Interaction of gamma-rays with the CMOS appeared as flashing bright spots on the image. The bright spots were then counted by using the freely available ImageJ software. Preliminary results indicated that the number of bright spots increased linearly with increase of gamma-ray dose rate. An in-house Android application software was then developed for real-time counting of the bright spots. The application software also allowed users to input a calibration equation so that the phones could simultaneously convert the count rate to display in dose rate. This research demonstrated that, after appropriate calibration, smartphones could be used as gamma-ray measuring devices for radiation safety control involving high activity sources such as in industrial radiography, gamma-ray irradiation facility and medical treatment.
