Development of x-ray CCD camera system with high readout rate using ASIC
Development of x-ray CCD camera system with high readout rate using ASIC
复制标题
DOI：
10.1117/12.788257
复制
发表时间：
2008-07
期刊：
影响因子：
--
通讯作者：
H. Nakajima;D. Matsuura;N. Anabuki;E. Miyata;H. Tsunemi;J. Doty;H. Ikeda;H. Katayama
中科院分区：
文献类型：
--
作者：
H. Nakajima;D. Matsuura;N. Anabuki;E. Miyata;H. Tsunemi;J. Doty;H. Ikeda;H. Katayama
介绍了基于ASIC和camera Link标准的x射线CCD相机高速低噪声读出系统的研制。该ASIC具有ad转换能力，能够以600 kHz的高像素率处理CCD输出信号，比传统的帧传输型在轨x射线CCD相机快10倍。芯片内部有四个相同的电路，它们同时处理CCD信号。采用ΔΣ调制器实现有效的噪声整形，以相对简单的电路获得高分辨率的十进制值。单元测试结果表明，在625 kHz像素率~70 μV和~40 μV @ 40 kHz像素率输入噪声较低的情况下，该电路工作正常。功耗足够低，<120 μuV @ 1.25 MHz。我们还开发了其余的读出和驱动电路。为了支持ASIC的高读出率，我们采用Camera Link标准作为数据采集方案。在CCD相机系统的初始测试中，我们使用了为日本下一代x射线天文卫星上的软x射线成像仪开发的p通道CCD。它的损耗层厚度高达220 μm，因此我们可以以高灵敏度探测来自109Cd的x射线，而不是n通道ccd。我们的系统能量分辨率为379（±7）eV (FWHM) @ 22.1 keV，即ΔE/E=1.8%，读出率为44 kHz。
We report on the development of high-speed and low-noise readout system of X-ray CCD camera with ASIC and the Camera Link standard. The ASIC is characterized by AD-conversion capability and it processes CCD output signals with a high pixel rate of 600 kHz, which is ten times quicker than conventional frame transfer type X-ray CCD cameras in orbit. There are four identical circuits inside the chip and all of them process CCD signals simultaneously. ΔΣ modulator is adopted to achieve effective noise shaping and obtain a high resolution decimal values with relatively simple circuits. The results of the unit test shows that it works properly with moderately low input noise of ~70 μV at pixel rate of 625 kHz, and ~40 μV @ 40 kHz. Power consumption is sufficiently low of <120 μuV @ 1.25 MHz. We have also developed the rest of readout and driving circuits. As a data acquisition scheme we adopt the Camera Link standard in order to support the high readout rate of the ASIC. In the initial test of the CCD camera system, we used the P-channel CCD developed for Soft X-ray Imager onboard next Japanese X-ray astronomical satellite. The thickness of its depletion layer reaches up to 220 μm and therefore we can detect the X-rays from 109Cd with high sensitivity rather than N-channel CCDs. The energy resolution by our system is 379 (±7)eV (FWHM) @ 22.1 keV, that is, ΔE/E=1.8% was achieved with a readout rate of 44 kHz.