This paper presents a high precision CMOS weak current readout circuit.This circuit is capable of converting a weak current into a frequency signal for amperometric measurements with high precision and further deliver...This paper presents a high precision CMOS weak current readout circuit.This circuit is capable of converting a weak current into a frequency signal for amperometric measurements with high precision and further delivering a 10-bit digital output.A fast stabilization-enhanced potentiostat has been proposed in the design, which is used to maintain a constant bias potential for amperometric biochemical sensors.A technique based on source voltage shifting that reduces the leakage current of the MOS transistor to the reverse diode leakage level at room temperature was employed in the circuit.The chip was fabricated in the 0.35 μm chartered CMOS process, with a single 3.3 V power supply.The interface circuit maintains a dynamic range of more than 100 dB.Currents from 1 pA to 300 nA can be detected with a maximum nonlinearity of 0.3% over the full scale.展开更多
碲镉汞短波红外焦平面探测器在红外天文观测中具有重要作用。采用光子转移曲线(Photon Transfer Curve, PTC)来表征探测器性能参数是一种重要的测试方法。根据PTC测量探测器的增益是表征探测器其他性能的前提。采用碲镉汞液相外延薄膜...碲镉汞短波红外焦平面探测器在红外天文观测中具有重要作用。采用光子转移曲线(Photon Transfer Curve, PTC)来表征探测器性能参数是一种重要的测试方法。根据PTC测量探测器的增益是表征探测器其他性能的前提。采用碲镉汞液相外延薄膜材料和n-on-p芯片结构制备了640×512规格的红外探测器,探测器截止波长为2.0μm。用PTC方法测量红外焦平面探测器的增益,发现在焦平面上不同区域的增益是不均匀的,增益的非均匀性达到了20.2%。增益的非均匀性反映了探测器芯片内部性能的差异,尤其是不同光敏元噪声的差异。芯片加工过程可能是引起增益不均匀的原因之一。通过改进芯片工艺,特别是改进芯片的机械化学减薄工艺,降低抛光损伤,提高了探测器芯片表面不同区域的增益均匀性。改进工艺后,增益的非均匀性从20.2%降低到0.3%,获得了增益均匀的探测器芯片,增益的平均值为0.159 DN/e-,并测量得到探测器的暗电流为2.2 e-/s,读出噪声为67 e-。展开更多
A new wide-range fast readout system capable of adaptive identification is designed for wire scanners,which are used to measure beam profiles and emittance.This system is capable of handling varying current signals wi...A new wide-range fast readout system capable of adaptive identification is designed for wire scanners,which are used to measure beam profiles and emittance.This system is capable of handling varying current signals with Gaussian distributions and current pulses up to 1000 counts/s, as well as an input current range of 1 n A–1 m A. When tested, the resolution was found to exceed 3.68% for full scale, the nonlinearity was found to be less than 0.11%, and the measurement sensibility was found to be less than 5 p A. We believe that the system will play a crucial role in improving the measurement accuracy of beam diagnosis and the efficiency of accelerator operation,as well as decreasing the time required for beam tuning.This system was applied to the beam diagnosis of an injector II prototype for an accelerator-driven subcritical system and produced excellent measurement results. A description of the adaptive fast readout system for wire scanners is presented in this paper.展开更多
本文采用了自主研发的THGEM探测器,其具有双膜结构,64路直流读出电子学等特点。采用该THGEM探测器在K荧光装置上,开展了对15~70 ke V内多能量点X射线的探测实验工作;结果显示该THGEM探测器对宽能区、高注量(剂量当量)的X射线具有良好线...本文采用了自主研发的THGEM探测器,其具有双膜结构,64路直流读出电子学等特点。采用该THGEM探测器在K荧光装置上,开展了对15~70 ke V内多能量点X射线的探测实验工作;结果显示该THGEM探测器对宽能区、高注量(剂量当量)的X射线具有良好线性响应,并分析了影响探测效率的因素。展开更多
The photoelectric device of a scintillation dosimeter converts photons produced by radiation into an electrical signal.Its features directly determine the overall performance of the dosimeter.For a plastic scintillati...The photoelectric device of a scintillation dosimeter converts photons produced by radiation into an electrical signal.Its features directly determine the overall performance of the dosimeter.For a plastic scintillation fiber dosimeter(PSFD)with a current readout mode,systematic studies of the stability and light-dose response were performed for the photomultiplier tube(PMT),silicon photomultiplier(SiPM),avalanche photodiode(APD),and photodiode(PD).The temperature stability,long-term stability,repeatability,signal-to-noise ratio(SNR),and current dose response of the PSFD with the abovementioned photoelectric devices were studied using a pulsed LED light source and the Small Animal Radiation Therapy platform.An exponential relationship between the dark/ne current and temperature was obtained for all the devices.I is shown that the APD is the most sensitive device to temperature,with a current dependence on temperature reaching 6.5%C^(-1)at room temperature,whereas for the other devices this dependence is always<0:6%C^(-1).In terms of long-term stability,the net current of PD can change by up to 4%when working continuously for 8 h and 2%when working intermittently for 32 h,whereas for the other devices,the changes are all<1%.For the dose response,the PMT and SiPM exhibit excellent linear responses and SNRs within the range of 0.1-60 Gy/min For the PSFD with a current readout mode,the performance of the PMT and SiPM is concluded to be better than that of the other devices in the study.In particular,the SiPM,which has a compact size,low bias voltage,and antimagnetic interference,has great advantages for further applications.展开更多
基于电流镜积分读出电路的X射线CMOS图像传感器 (CMI X IS)的原理 ,并对电流镜积分读出电路进行了计算机模拟。对CMI X IS的性能参数进行了测试 ,并对光电转换特性曲线进行了分析。设计了CMI X IS的应用电路 ,得到了不同密度、不同尺寸...基于电流镜积分读出电路的X射线CMOS图像传感器 (CMI X IS)的原理 ,并对电流镜积分读出电路进行了计算机模拟。对CMI X IS的性能参数进行了测试 ,并对光电转换特性曲线进行了分析。设计了CMI X IS的应用电路 ,得到了不同密度、不同尺寸材料的视频信号波形。测试结果和实验表明 ,CMI X IS具有较低的暗噪声、较大的响应度、较高的输出电压和较宽的动态范围 ,可以应用于X射线实时成像检测领域。展开更多
CCD在成像过程中不可避免地引入一定的噪声,这些噪声将对以图像检测为基础的CCD各种工程应用带来误差。本文分析了各种CCD噪声的来源及其数学性质,并对科学级CCD Alta U9000相机的各种噪声进行了量化分析,给出了暗电流噪声、成像电路噪...CCD在成像过程中不可避免地引入一定的噪声,这些噪声将对以图像检测为基础的CCD各种工程应用带来误差。本文分析了各种CCD噪声的来源及其数学性质,并对科学级CCD Alta U9000相机的各种噪声进行了量化分析,给出了暗电流噪声、成像电路噪声及随机噪声的变化规律;对不同积分时间的图像进行了噪声抑制实验。实验证明,根据对U9000 CCD噪声的预先测试数据,其噪声中的暗电流噪声、成像电路噪声等系统噪声可以得到很大的抑制,而随机噪声无法抑制。展开更多
基金supported by the National High-Tech Research and Development Program of China(No.2007AA04Z349)
文摘This paper presents a high precision CMOS weak current readout circuit.This circuit is capable of converting a weak current into a frequency signal for amperometric measurements with high precision and further delivering a 10-bit digital output.A fast stabilization-enhanced potentiostat has been proposed in the design, which is used to maintain a constant bias potential for amperometric biochemical sensors.A technique based on source voltage shifting that reduces the leakage current of the MOS transistor to the reverse diode leakage level at room temperature was employed in the circuit.The chip was fabricated in the 0.35 μm chartered CMOS process, with a single 3.3 V power supply.The interface circuit maintains a dynamic range of more than 100 dB.Currents from 1 pA to 300 nA can be detected with a maximum nonlinearity of 0.3% over the full scale.
基金supported by the National Natural Science Foundation of China(Nos.11475233,11705257,and 11775285)
文摘A new wide-range fast readout system capable of adaptive identification is designed for wire scanners,which are used to measure beam profiles and emittance.This system is capable of handling varying current signals with Gaussian distributions and current pulses up to 1000 counts/s, as well as an input current range of 1 n A–1 m A. When tested, the resolution was found to exceed 3.68% for full scale, the nonlinearity was found to be less than 0.11%, and the measurement sensibility was found to be less than 5 p A. We believe that the system will play a crucial role in improving the measurement accuracy of beam diagnosis and the efficiency of accelerator operation,as well as decreasing the time required for beam tuning.This system was applied to the beam diagnosis of an injector II prototype for an accelerator-driven subcritical system and produced excellent measurement results. A description of the adaptive fast readout system for wire scanners is presented in this paper.
基金supported by the China Postdoctoral Science Foundation(No.2017M621818)the National Key Research and Development Project(Nos.2017YFF0206205 and2016YFB0501303)+1 种基金the National Natural Science Foundation of China(Nos.51873137 and 11705123)the Project of the State Key Laboratory of Radiation Medicine and Protection Soochow University(No.GZN1201801)。
文摘The photoelectric device of a scintillation dosimeter converts photons produced by radiation into an electrical signal.Its features directly determine the overall performance of the dosimeter.For a plastic scintillation fiber dosimeter(PSFD)with a current readout mode,systematic studies of the stability and light-dose response were performed for the photomultiplier tube(PMT),silicon photomultiplier(SiPM),avalanche photodiode(APD),and photodiode(PD).The temperature stability,long-term stability,repeatability,signal-to-noise ratio(SNR),and current dose response of the PSFD with the abovementioned photoelectric devices were studied using a pulsed LED light source and the Small Animal Radiation Therapy platform.An exponential relationship between the dark/ne current and temperature was obtained for all the devices.I is shown that the APD is the most sensitive device to temperature,with a current dependence on temperature reaching 6.5%C^(-1)at room temperature,whereas for the other devices this dependence is always<0:6%C^(-1).In terms of long-term stability,the net current of PD can change by up to 4%when working continuously for 8 h and 2%when working intermittently for 32 h,whereas for the other devices,the changes are all<1%.For the dose response,the PMT and SiPM exhibit excellent linear responses and SNRs within the range of 0.1-60 Gy/min For the PSFD with a current readout mode,the performance of the PMT and SiPM is concluded to be better than that of the other devices in the study.In particular,the SiPM,which has a compact size,low bias voltage,and antimagnetic interference,has great advantages for further applications.
文摘基于电流镜积分读出电路的X射线CMOS图像传感器 (CMI X IS)的原理 ,并对电流镜积分读出电路进行了计算机模拟。对CMI X IS的性能参数进行了测试 ,并对光电转换特性曲线进行了分析。设计了CMI X IS的应用电路 ,得到了不同密度、不同尺寸材料的视频信号波形。测试结果和实验表明 ,CMI X IS具有较低的暗噪声、较大的响应度、较高的输出电压和较宽的动态范围 ,可以应用于X射线实时成像检测领域。
文摘CCD在成像过程中不可避免地引入一定的噪声,这些噪声将对以图像检测为基础的CCD各种工程应用带来误差。本文分析了各种CCD噪声的来源及其数学性质,并对科学级CCD Alta U9000相机的各种噪声进行了量化分析,给出了暗电流噪声、成像电路噪声及随机噪声的变化规律;对不同积分时间的图像进行了噪声抑制实验。实验证明,根据对U9000 CCD噪声的预先测试数据,其噪声中的暗电流噪声、成像电路噪声等系统噪声可以得到很大的抑制,而随机噪声无法抑制。
