Noise measurements in charge-coupled devices

Noise analysis of buried channel CCD by computer simulation is presented. The potential profile and signal charge distribution in potential well are obtained by solving Poisson's equation with a depletion approximation model. According to this model, it is possible to predict the volume occupied by signal charges in potential well. Thereby, the well capacitance and free carrier density are obtained. Then the device noise in the buried channel charge-coupled device, including the output reset noise, dark current noise, transfer noise and electrical injection noise at the input, can be calculated. Also, the charge handling capacity can be evaluated by integrating over the charge occupied volume.The dependences of the electrical injection noise and transfer noise on charge packet size and operating frequency have been calculated. This model can also calculate quantitatively the dependence of the charge handling capacity and the position of maximum potential on the magnitude of clock voltage.The noise behavior of BCCDs is measured with respect to different input charges, clock magnitudes, and frequencies. Experimental results reveal that if the device is operated near the saturation region, in which V out /V in maintain a linear relationship but the gain of the output amplifier starts to saturate, then the input noise may be reduced by a factor of about 2.

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“…12 [10]. We used a spectrum analyzer to measure the noise spectrum density and a digital storage oscilloscope to monitor waveforms.…”

Section: Experimental Methodsmentioning

confidence: 99%

Noise analysis and measurements on buried channel charge coupled devices

Houng

Chen

Gong

et al. 1992

Journal of the Chinese Institute of Engineers

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“…This implant forms a subchannel, or a "notch" in the potential profile of the transfer channel [4], thereby confining the charge packet to a fraction of the pixel volume. According to a simplified model [5], the CTI is given by , where is the trap density, is the electron density in a pixel holding a charge packet to be transferred, and is the trap effectiveness factor, which is the probability that a filled trap releases its charge during the overlap period between clocks multiplied by the probability that a trap filled by a previous event is still filled. If the charge is confined to a narrow region, the value of CTI is improved.…”

Section: Introductionmentioning

confidence: 99%

Application of a mesh experiment for a proton beam onto the charge-coupled device

Tsunemi

Miki

Miyata

2004

IEEE Trans. Nucl. Sci.

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Radiation hardness is one of the most important characteristics in a space-borne instrument, particularly imaging devices. The charge-coupled device (CCD) is now used in the X-ray region. A "notch" structure inside the CCD is widely employed to make it radiation hard. Using a proton beam, we confirmed that the notch structure improved the charge transfer inefficiency (CTI) by a factor of three. We applied a mesh technique in the proton beam experiment of a CCD. The proton beam energy is 600 keV, which induces greater damage than do the beam of high energy widely reported. The CCD employed has 1024 1024 pixels with a notch structure. The mesh technique enables us to confine the proton beam to a circular region of 2 m diameter within a 24 24 m 2 pixel. The CCD was kept at 100 C during the irradiation. Some pixels are damaged in the notch region while others in the out-of-notch region. After the proton irradiation, we measured the CTI using 2 10 7 X-ray photons from 55 Fe, and found that the CTI of pixels damaged in the notch region is larger by a factor of 2.5 than that of pixels damaged in the out-of-notch region. It is still in open question as to whether pixels damaged in the out-of-notch region show a substantial radiation damage effect.

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“…The measurement techniques for the characteristic parameters of CCDs and CCD cameras are introduced in many papers and books [1][2][3][4][5][6][7][8][9] . Among these parameters, CTE is concerned in this paper because during the calculation of CTE for 2 KAF-4301E CCDs using Fe 55 x-ray images, it is found that the traditional CTE algorithm will not produce good results sometimes and occasionally makes mistakes when the CTE performance of the tested camera is very high.…”

Section: Introductionmentioning

confidence: 99%

New algorithm for absolute CTE measurement

Wang

2006

SPIE Proceedings

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Charge transfer efficiency (CTE) is a very important characteristic parameter for the CCD in the scientific imaging applications, especially in the imaging systems used to observe very faint objects such as night astronomical cameras. Several popular CTE measurement techniques are introduced briefly in this paper, deficiencies in the techniques are pointed out, and then some improvements are made. The modified algorithm for CTE measurement is based on the xray transfer and the MATLAB. When the algorithm begins, an appropriate initial charge transfer line from the x-ray single-pixel-events plot and its interzone for computation are determined by the user-PC interaction, and then a linear fit is performed in the interzone so as to get a more accurate transfer line. Thus a new interzone is obtained and a next linear fit can be done. In this way, a more accurate value of CTE can be obtained. Usually the algorithm stops after 5 to 10 iteration steps. Moreover the accuracy of the algorithm is discussed. Finally, the algorithm is used to estimate the horizontal CTE for 2 KAF-4301E CCDs tested at low temperatures. The results indicate that, when the CCD operating temperature is reduced below its absolute minimum rating, although the dark current performance improves obviously, the CTE performance degrades rapidly. An analysis and discussion for the results at the depth of theory is presented.

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Noise measurements in charge-coupled devices

Cited by 5 publications

References 6 publications

Noise analysis and measurements on buried channel charge coupled devices

Noise analysis and measurements on buried channel charge coupled devices

Application of a mesh experiment for a proton beam onto the charge-coupled device

New algorithm for absolute CTE measurement

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