CCD的近红外敏化技术

理论上硅ＣＣＤ在０．１ｎｍ到１．１μｍ之间都有响应,但通常此种器件在８００ｎｍ以后量子效率下降明显,一般会小于５０％,其中最主要的原因是近红外光子的吸收深度大于ＣＣＤ的外延层厚度,使大量光子穿透整个器件。显然增加外延层的厚度是解决这一问题的良好途径,但随着外延层的增加,必须使用高阻抗的材料,否则会明显的减低分辨率,另外增透膜的使用也会使量子效率大幅度提高,而且有效的减弱了干涉条纹的影响,新型Ｐ沟道     

CCD蓝敏技术

ＣＣＤ用于文领域已经有近２０ａ（年）的历史,随着ＣＣＤ技术的发展,作为重要参数之一的量子效率也得到极大提高,已经有许多效率在蓝端超过９０％的芯片应用于天文观测。本文介绍了提高ＣＣＤ蓝端量子效率的多种方法,包括电极减薄,Ｌｕｍｏｇｅｎ镀膜等等。可以看到,采用ＣＣＤ减薄、电荷注入和选择合适的增透膜可以使量子效率接近１００％。     

CCD蓝敏技术

Ｃ Ｃ Ｄ 用于天文领域已经有近２０ａ （ 年） 的历史, 随着 Ｃ Ｃ Ｄ 技术的发展, 作为重要参数之一的量子效率也得到极大提高, 已经有许多效率在蓝端超过９０ ％ 的芯片应用于天文观测。本文介绍了提高 Ｃ Ｃ Ｄ 蓝端量子效率的多种方法, 包括电极减薄、 Ｌｕｍｏｇｅｎ 镀膜、 Ｃ Ｃ Ｄ 减薄、紫外预照、电子预注入和增透膜等技术等等。可以看到, 采用 Ｃ Ｃ Ｄ 减薄、电荷注入和选择合适的增透膜可以使量子效率接近１００ ％     

天文用电荷耦合器件的实验室检测

介绍云南天文台ＣＣＤ检测实验室检测天文用ＣＣＤ系统的方法,检测参数主要包括：线性、噪声、增益、量子效率以及转移效率等．     

海尔-波普彗星的一个可能的巨大等离子体喷流

１９９６年９月１１日，使用上海天文台１．５６ｍ望远镜和Ｓｅｒｉｅｓ２００ＣＣＤ照相机，在Ｂ波段发现海尔波普彗星有一个巨大的喷流，初步认定为等离子喷流．     

海尔—波普彗星的一个可能的巨大等离子体喷流

１９９６年９月１１日，使用上海天台１．５６ｍ望远镜和Ｓｅｒｉｓ２００ＣＣＤ照相机，在Ｂ波段发现海尔－波普彗星有一个巨大的喷流，初步认定为等离子喷流。     

中国等高仪星表的现状和未来

自七十年代后期起，中国的４架光电等高仪就开始注重于旨在改进基本星表系统的观测．这４架光电等高仪均实现了现代化改造：实现全自动化操作和采用光子计数记录，这使得仪器能通宵达旦地工作，效率倍增．近年来用中国光电等高仪的观测已经编算出几部等高仪星表，其两个坐标（α和δ）的精度都很好，极限三等可达１１ｍ以上．将来这４架光电等高仪和即将用ＣＣＤ装备的Ⅲ型光电等高仪将会对基本天体测量做出更大贡献．     

SL9彗星撞击木星时S碎片的CCD观测

用上海天文台１．５６ｍ望远镜和ＣＣＤ照相机，观测ｓ＝５碎片时，发现了类似彗尾的奇异现象。     

SL9彗星撞击木星时S碎片的CCD观测

用上海天台１．５６ｍ望远镜和ＣＣＤ照相机，观测Ｓ＝５碎片时，发现了类似彗尾的奇异现象。     

天文用电荷耦合器件的实验室检测

介绍云南天台ＣＣＤ检测实验室检测天用ＣＣＤ系统的方法,检测参数主要包括：线性、噪声、增益、量子效率以及转移效率等。     

Achieving sub electron noise in CCD systems by means of digital filtering techniques that lower 1/f pixel correlated noise

Scientific CCDs designed in thick high resistivity silicon (Si) are excellent detectors for astronomy, high energy and nuclear physics, and instrumentation. Many applications can benefit from CCDs ultra low noise readout systems. The present work shows how sub electron noise CCD images can be achieved using digital signal processing techniques. These techniques allow 0.4 electrons of noise at readout bandwidths of up to 10?Kpixels per second while keeping the full CCD spatial resolution and signal dynamic range.     

The Ultimate CCD for Laser Guide Star Wavefront Sensing on Extremely Large Telescopes

All of the extremely large telescopes (ELTs) will utilize sodium laser guide star (LGS) adaptive optics (AO) systems. Most of these telescopes plan to use the Shack-Hartmann approach for wavefront sensing. In these AO systems, the laser spots in subapertures at the edge of the pupil will suffer from spot elongation due to the 10 km extent of the sodium layer and the large separation from the projection laser. This spot elongation will severely degrade the performance of standard geometry wavefront sensing systems. In this paper, we present a CCD with custom pixel morphology that aligns the pixels of each subaperture with the radial extension of the LGS spot. This CCD design will give better performance than a standard geometry CCDs for continuous wave lasers. In addition, this CCD design is optimal for a pulsed sodium laser. The pixel geometry enables each subaperture to follow a laser pulse traversing the sodium layer, providing optimal sampling of a limited number of detected photons. In addition to novel pixel layout, this CCD will also incorporate experimental JFET sense amplifiers and use CMOS design approaches to simplify the routing of biases, clocks and video output. This CCD will attain photon-noise limited performance at high frame rates, and is being incorporated in the plans for the Thirty Meter Telescope (TMT).     

MARSIS surface reflectivity of the south residual cap of Mars

The south residual cap of Mars is commonly described as a thin and bright layer of CO₂-ice. The Mars Advanced Radar for Subsurface and Ionospheric Sounding (MARSIS) is a low-frequency radar on board Mars Express operating at the wavelength between 55 and 230 m in vacuum. The reflection of the radar wave on a stratified medium like the residual cap can generate interferences, causing weaker surface reflections compared to reflections from a pure water ice surface. In order to understand this anomalous low reflectivity, we propose a stratified medium model, which allows us to estimate both the thickness and the dielectric constant of the optically thin slab. First, we consider the residual cap as single unit and show that the decrease in the reflected echo strength is well explained by a mean thickness of 11 m and a mean dielectric constant of 2.2. This value of dielectric constant is close to the experimental value 2.12 for pure CO₂-ice. Second, we study the spatial variability of the radar surface reflectivity. We observe that the reflectivity is not homogeneous over the residual cap. This heterogeneity can be modeled either by variable thickness or variable dielectric constant. The surface reflectivity shows that two different units comprise the residual cap, one central unit with high reflectivity and surrounding, less reflective units.     

Photon counting strategies with low-light-level CCDs

Low light level charge-coupled devices (L3CCDs) have recently been developed, incorporating on-chip gain. They may be operated to give an effective readout noise of much less than one electron by implementing an on-chip gain process allowing the detection of individual photons. However, the gain mechanism is stochastic and so introduces significant extra noise into the system. In this paper we examine how best to process the output signal from an L3CCD so as to minimize the contribution of stochastic noise, while still maintaining photometric accuracy.
We achieve this by optimizing a transfer function that translates the digitized output signal levels from the L3CCD into a value approximating the photon input as closely as possible by applying thresholding techniques. We identify several thresholding strategies and quantify their impact on the photon counting accuracy and the effective signal-to-noise ratio.
We find that it is possible to eliminate the noise introduced by the gain process at the lowest light levels. Reduced improvements are achieved as the light level increases up to about 20 photon pixel⁻¹ and above this there is negligible improvement. Operating L3CCDs at very high speeds will keep the photon flux low, giving the best improvements in signal-to-noise ratio.     

A New Machine for Planarity Measurement of CCDs and Mosaics of CCDs

High quality CCD detectors are now being produced with 2048× 4096 square pixels, each 15 m on a side. Evenlarger detector areas are built with several CCDs mounted into amosaic. To be useful in an instrument the light must be in focuson all CCDs, requiring that all CCDs in a mosaic must typicallybe aligned within 30 micron of a flat plane. To achieve thisaccuracy in many cases the measurement and correction of the CCDalignment is necessary. One way allowing a surface measurement,even when the CCD is protected by a window, is to usetriangulation sensor. The principle of a triangulation sensor,its application and its implementation in a measuring machineare presented here.     

Charge coupled devices (CCDs) in X-ray astronomy

The application of CCDs to X-ray imaging and spectroscopy for astronomy is described. The requirements which differ markedly from those of traditional optical applications are highlighted. Results of recent research programs to optimize CCD X-ray response are presented. It is shown that very high quantum efficiencies and Fano noise limited energy resolutions can be obtained. A number of issues related to the practical implementation of future instruments are reviewed.     

RTS2中新CCD类型扩展方法

CCD是天文望远镜中最常见的观测终端设备,也是望远镜自主控制系统中的重要组成部分。随着天文望远镜自主观测需求的不断出现以及技术的快速发展,开源的RTS2软件系统成为目前该领域研究中受到较多关注的系统之一。但RTS2支持的CCD设备较为有限,同时控制接口约定也相对固定。在针对部分特殊的CCD设备(如LAMOST中采用的32台CCD设备、选址用的部分CCD设备)时,仅实现原有类的方法是不够的。在深入分析RTS2源码的基础上,重点从参数、命令、协议扩展方面研究基于原有的Camera类,通过继承的方法构造新的CCD类型,实现对LAMOST项目的 CCD控制,取得了较好的效果,对在RTS2中集成望远镜系统其他类型设备也有较好的参考价值。     

Calibration of flight model CCDs for CoRoT mission

CoRoT (Convection, Rotation and Transit) is a mission of high-accuracy photometry with two scientific programmes: asteroseismology and planet finding, using CCDs as detectors. Ten 2048×4096 CCDs manufactured by E2V (42-80) were calibrated on Meudon test bench in order to choose the best ones for flight. A very high instrument stability is needed. Taking into account the environmental perturbations (temperature, attitude control system jitter, radiations, etc.) we studied sensitivity of CCD gain and quantum efficiency to temperature and sensitivity of the output signal to bias voltages. Special attention was paid to pixel capacity and noise sources coming from dark current and pixel response non-uniformity. The calibration results together with the expected voltages and temperature fluctuations are compared with the specifications.     

Secrets of E2V Technologies CCDs (ex Marconi CCDs)

To complement previously published information on E2V CCDs, we present here some less well-known information about Marconi CCDs. We show details of the performance of deep depletion silicon variants, and discuss other subtleties of performance. We also present an update on L3vision (sub-electron noise) devices, indicating current availability, options, and ongoing development work. Finally, we will give a flavour of the range of custom designs that have been made. Many of these are not commercially available, and may not be familiar to all astronomers or CCD technologists. This revised version was published online in July 2006 with corrections to the Cover Date.     

Possible Contribution of Mature γ-ray Pulsars to Cosmic-ray Positrons

We restudy the possible contribution of mature gamma-ray pulsars to cosmic ray positrons based on the new version of outer gap model. In this model, the inclination angle and average properties of the outer gap are taken into account, and more mature pulsars can have the outer gap and emit high energy photons. Half of the primary particles in the outer gaps will flow back toward the star surface and emit synchrotron photons, which can produce electron/positron pairs by the cascade of pair production. Some of these pairs will escape from the light cylinder and be accelerated to relativistic energies in the pulsar wind driven by low-frequency electromagnetic waves. Using a Monte Carlo method, we obtain a sample of mature gamma-ray pulsars and then calculate the production of the positrons from these pulsars. The observed excess of cosmic positrons can be well explained by this model.