ASTM E2642-09(R2021) pdf free download

ASTM E2642-09(R2021) pdf free download.Standard Terminology for Scientific Charge-Coupled Device (CCD) Detectors
1. Scope
1.1 This terminology brings together and clarifies the basic terms and definitions used with scientific grade cooled charge- coupled device (CCD) detectors, thus allowing end users and vendors to use common documented terminology when evalu- ating or discussing these instruments. CCD detectors are sensitive to light in the region from 200 nm to 1100 nm and the terminology outlined in the document is based on the detection technology developed around CCDs for this range of the spectrum. 1.2 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. 1.3 This international standard was developed in accor- dance with internationally recognized principles on standard- ization established in the Decision on Principles for the Development of International Standards, Guides and Recom- mendations issued by the World Trade Organization Technical Barriers to Trade (TBT) Committee.
4. Terminology
4.1 Definitions: advanced inverted mode operation (AIMO), n—a commer- cial tradename given to a method of reducing the rate of generation of dark current. Also known as multi-pinned phase operation. analog-to-digital (A/D) converter, n—an electronic circuitry in a CCD detector that converts an analog signal into digital values, which are specified in terms of bits that can be manipulated by the computer. anti-blooming structure, n—a structure built into the pixel to prevent signal charge above full-well capacity from bloom- ing into adjacent pixels. D ISCUSSION —Anti-blooming structures bleed off any excess charge before they can overflow the pixel and thereby stop blooming. These structures can reduce the effective quantum efficiency and introduce nonlinearity into the sensor. antireflective (AR) coating, n—a coating applied to either the front surface of the CCD or the vacuum window surfaces, to minimize the amount ofreflected energy (or electromagnetic radiation) so as to maximize the amount of transmitted energy. back-illuminated CCD (BI CCD), n—a type of CCD that has been uniformly reduced in thickness on the side away from the gate structure (see Fig. 1b) and positioned such that the photons are detected on that side. D ISCUSSION —A BI CCD leads to an improvement in sensitivity to incoming photons from the soft X-ray to the near-infrared (NIR) regions of the spectrum with the highest response in the visible region. However, compared to a front-illuminated CCD, it suffers from higher dark currents and interference fringe formation (etaloning) usually in the NIR region. Also called back-thinned CCD.binning, n—the process of combining charge from adjacent pixels in a CCD prior to read out. D ISCUSSION —There are two main types of binning: (1) vertical binning and (2) horizontal binning (see Fig. 2). Summing charge on the CCD and doing a single readout results in better noise performance than reading out several pixels and then summing them in the computer memory. This is because each act of reading out contributes to noise (see noise). CCD bias, n—the minimum analog offset added to the signal before the A/D converter to ensure a positive digital output each time a signal is read out. D ISCUSSION —The CCD bias is set at the time of manufacture and remains set over the lifetime of the camera.charge, n—measure of number of electrons that are contained in a pixel potential well. charge-coupled device (CCD), n—a silicon-based semicon- ductor chip consisting of a two-dimensional matrix of photo sensors or pixels (see Fig. 3). D ISCUSSION —The matrix is usually referred to as the image area. Electronic charge is accumulated on the image area and transferred out by the application of electrical potentials to shielded electrodes. The size of pixels in the sensor is typically 26 µm × 26 µm; however, sensors can be manufactured in a variety ofdifferent pixel sizes ranging from 6 µm × 6 µm to 50 µm × 50 µm. Although mathematically incorrect, the dimension unit of a square pixel is typically given in square microns (for example, a pixel of dimension 26 µm × 26 µm is specified as 26 × 26 µm 2 ).