Readout noise is a critical parameter for characterizing the performance of charge-coupled devices（CCDs）, which can be greatly reduced by the correlated double sampling（CDS） circuit. However, a conventional CDS ci...Readout noise is a critical parameter for characterizing the performance of charge-coupled devices（CCDs）, which can be greatly reduced by the correlated double sampling（CDS） circuit. However, a conventional CDS circuit inevitably introduces new noise since it consists of several active analog components such as operational amplifiers. This paper proposes a digital CDS circuit technique, which transforms the pre-amplified CCD signal into a train of digital presentations by a high-speed data acquisition card directly without the noisy CDS circuit,then implements the digital CDS algorithm through a numerical method. A readout noise of 3.3 e- and an energy resolution of 121 e V@5.9 ke V can be achieved via the digital CDS technique.展开更多
Charged Coupled Devices （CCDs） have been successfully used in several low energy X-ray astronomical satellites over the past two decades. Their high energy resolution and high spatial resolution make them a perfect ...Charged Coupled Devices （CCDs） have been successfully used in several low energy X-ray astronomical satellites over the past two decades. Their high energy resolution and high spatial resolution make them a perfect tool for low energy astronomy, such as observing the formation of galaxy clusters and the environment around black holes. The Low Energy X-ray Telescope （LE） group is developing a Swept Charge Device （SCD） for the Hard X- ray Modulation Telescope （HXMT） satellite. A SCD is a special low energy X-ray CCD, which can be read out a thousand times faster than traditional CCDs, simultaneously keeping excellent energy resolution. A test method for measuring the charge transfer efficiency （CTE） of a prototype SCD has been set up. Studies of the charge transfer inefficiency （CTI） with a proton-irradiated SCD have been performed at a range of operating temperatures. The SCD is irradiated by 3× 10Sere-2 10 MeV protons.展开更多
The Low Energy X-ray Telescope is one of the main payloads on the Hard X-ray Modulation Telescope satellite. Swept charge devices （SCDs） are selected as detectors for the Low Energy X-ray Telescope. As SCDs are sens...The Low Energy X-ray Telescope is one of the main payloads on the Hard X-ray Modulation Telescope satellite. Swept charge devices （SCDs） are selected as detectors for the Low Energy X-ray Telescope. As SCDs are sensitive to proton irradiation, irradiation tests were carried out on the HI-13 accelerator at the China Institute of Atomic Energy. The beam energy was measured to be 10 MeV at the SCD. The proton fluence delivered to the SCD was 3×10^8protons/cm2 over two hours. By comparing the performance before and after irradiation, it is concluded that proton irradiation affects both the dark current and the charge transfer inefficiency of the SCD. The energy resolution of the proton-irradiated SCD is 212 eV@5.9 keV at -60℃, while it before irradiated is 134 eV. Moreover, better performance can be reached by lowering the operating temperature of the SCD in orbit.展开更多
We present the low temperature testing of an SCD detector, investigating its performance such as readout noise, energy resolution at 5.9 keV and dark current. The SCD’s performance is closely related to temperature, ...We present the low temperature testing of an SCD detector, investigating its performance such as readout noise, energy resolution at 5.9 keV and dark current. The SCD’s performance is closely related to temperature, and the temperature range of 80℃ to 50℃ is the best choice, where the FWHM at 5.9 keV is about 130 eV. The influence of the neutron irradiation from an electrostatic accelerator with fluence up to 1 × 109 cm-2 has been examined. We find the SCD is not vulnerable to neutron irradiation. The detailed operations of the SCD and the test results of low temperature are reported, and the results of neutron irradiation are discussed.展开更多
A readout system for X-ray CCDs based on an improved architecture is presented; by optimizing several critical circuit blocks along the analog signal chain, the conflict between the readout speed and readout noise is ...A readout system for X-ray CCDs based on an improved architecture is presented; by optimizing several critical circuit blocks along the analog signal chain, the conflict between the readout speed and readout noise is greatly alleviated. Using CCD47-10 as its target CCD, the readout system has achieved 8.6e^- readout noise and 142 eV FWHM at 5.9 keV Mn Kα under a pixel rate of 80 kHz. Also its performance of imaging has been investigated.展开更多
基金Supported by National Natural Science Foundation of China(10978002)
文摘Readout noise is a critical parameter for characterizing the performance of charge-coupled devices（CCDs）, which can be greatly reduced by the correlated double sampling（CDS） circuit. However, a conventional CDS circuit inevitably introduces new noise since it consists of several active analog components such as operational amplifiers. This paper proposes a digital CDS circuit technique, which transforms the pre-amplified CCD signal into a train of digital presentations by a high-speed data acquisition card directly without the noisy CDS circuit,then implements the digital CDS algorithm through a numerical method. A readout noise of 3.3 e- and an energy resolution of 121 e V@5.9 ke V can be achieved via the digital CDS technique.
文摘Charged Coupled Devices （CCDs） have been successfully used in several low energy X-ray astronomical satellites over the past two decades. Their high energy resolution and high spatial resolution make them a perfect tool for low energy astronomy, such as observing the formation of galaxy clusters and the environment around black holes. The Low Energy X-ray Telescope （LE） group is developing a Swept Charge Device （SCD） for the Hard X- ray Modulation Telescope （HXMT） satellite. A SCD is a special low energy X-ray CCD, which can be read out a thousand times faster than traditional CCDs, simultaneously keeping excellent energy resolution. A test method for measuring the charge transfer efficiency （CTE） of a prototype SCD has been set up. Studies of the charge transfer inefficiency （CTI） with a proton-irradiated SCD have been performed at a range of operating temperatures. The SCD is irradiated by 3× 10Sere-2 10 MeV protons.
基金Supported by National Natural Science Foundation of China(10978002)
文摘The Low Energy X-ray Telescope is one of the main payloads on the Hard X-ray Modulation Telescope satellite. Swept charge devices （SCDs） are selected as detectors for the Low Energy X-ray Telescope. As SCDs are sensitive to proton irradiation, irradiation tests were carried out on the HI-13 accelerator at the China Institute of Atomic Energy. The beam energy was measured to be 10 MeV at the SCD. The proton fluence delivered to the SCD was 3×10^8protons/cm2 over two hours. By comparing the performance before and after irradiation, it is concluded that proton irradiation affects both the dark current and the charge transfer inefficiency of the SCD. The energy resolution of the proton-irradiated SCD is 212 eV@5.9 keV at -60℃, while it before irradiated is 134 eV. Moreover, better performance can be reached by lowering the operating temperature of the SCD in orbit.
基金Supported by HXMT Project and Open Project of State Key Laboratory of Nuclear Physics and Technology (Peking University)
文摘We present the low temperature testing of an SCD detector, investigating its performance such as readout noise, energy resolution at 5.9 keV and dark current. The SCD’s performance is closely related to temperature, and the temperature range of 80℃ to 50℃ is the best choice, where the FWHM at 5.9 keV is about 130 eV. The influence of the neutron irradiation from an electrostatic accelerator with fluence up to 1 × 109 cm-2 has been examined. We find the SCD is not vulnerable to neutron irradiation. The detailed operations of the SCD and the test results of low temperature are reported, and the results of neutron irradiation are discussed.
基金Supported by National Natural Science Foundation of China (10978002)Youth Innovation Foundation of IHEP(H95461JOU2)
文摘A readout system for X-ray CCDs based on an improved architecture is presented; by optimizing several critical circuit blocks along the analog signal chain, the conflict between the readout speed and readout noise is greatly alleviated. Using CCD47-10 as its target CCD, the readout system has achieved 8.6e^- readout noise and 142 eV FWHM at 5.9 keV Mn Kα under a pixel rate of 80 kHz. Also its performance of imaging has been investigated.
