A charge-coupled device ( CCD ) is an integrated circuit containing an array of linked, or coupled, capacitors . Under the control of an external circuit, each capacitor can transfer its electric charge to a neighboring capacitor. CCD sensors are a major technology used in digital imaging .
100-435: MS4 , or similar, may refer to: 2002 MS 4 , a possible dwarf planet MS4 Modeling Environment , a software package Metal Slug 4 , a video game Mississippi Highway 4 Mississippi's 4th congressional district Municipal Separate Storm Sewer System (MS4) required pursuant to United States law to regulate stormwater runoff [REDACTED] Topics referred to by
200-423: A charge amplifier , which converts the charge into a voltage . By repeating this process, the controlling circuit converts the entire contents of the array in the semiconductor to a sequence of voltages. In a digital device, these voltages are then sampled, digitized, and usually stored in memory; in an analog device (such as an analog video camera), they are processed into a continuous analog signal (e.g. by feeding
300-481: A shift register . The essence of the design was the ability to transfer charge along the surface of a semiconductor from one storage capacitor to the next. The concept was similar in principle to the bucket-brigade device (BBD), which was developed at Philips Research Labs during the late 1960s. The first experimental device demonstrating the principle was a row of closely spaced metal squares on an oxidized silicon surface electrically accessed by wire bonds. It
400-468: A 10-million-year timespan and found that it may be in an intermittent 18:11 mean-motion orbital resonance with Neptune, which seems to cause irregular fluctations in 2002 MS 4 's orbital inclination and eccentricity. Despite this, researchers do not consider 2002 MS 4 to be in resonance with Neptune. In the night sky, 2002 MS 4 is located near the Milky Way 's Galactic Center in
500-485: A CCD is the higher cost: the cell area is basically doubled, and more complex control electronics are needed. An intensified charge-coupled device (ICCD) is a CCD that is optically connected to an image intensifier that is mounted in front of the CCD. An image intensifier includes three functional elements: a photocathode , a micro-channel plate (MCP) and a phosphor screen. These three elements are mounted one close behind
600-669: A cooling system—using either thermoelectric cooling or liquid nitrogen—to cool the chip down to temperatures in the range of −65 to −95 °C (−85 to −139 °F). This cooling system adds additional costs to the EMCCD imaging system and may yield condensation problems in the application. However, high-end EMCCD cameras are equipped with a permanent hermetic vacuum system confining the chip to avoid condensation issues. The low-light capabilities of EMCCDs find use in astronomy and biomedical research, among other fields. In particular, their low noise at high readout speeds makes them very useful for
700-423: A crater-like depression 322 ± 39 km (200 ± 24 mi) wide and 45.1 ± 1.5 km (28.02 ± 0.93 mi) deep, and a 25 +4 −5 km ( 15.5 +2.5 −3.1 mi )-tall peak near the rim of the depression. Another depression feature about 10 km (6.2 mi) wide and 11 km (6.8 mi) deep was detected by a single telescope from Varages, France during
800-614: A depression feature at least 8 km (5 mi) deep. The topographic peak on 2002 MS 4 has a height comparable to Mars 's tallest mountain, Olympus Mons , and the central mound of the Rheasilvia crater on asteroid Vesta. If 2002 MS 4 's topographic peak is a mountain, then it would qualify as one of the tallest known mountains in the Solar System . It is possible that this topographic peak may actually be an unknown 213 km (132 mi)-diameter satellite that
900-598: A depth of up to 25 km (16 mi). The rotation period of 2002 MS 4 is uncertain and its rotational axial tilt is unknown. It is difficult to measure 2002 MS 4 's rotation period photometrically with telescopes on Earth since the object is obscured in a dense field of background stars. Due to 2002 MS 4 's spheroidal shape and possible surface albedo variations, its light curve only exhibits very small fluctuations in brightness (amplitude 0.05–0.12 mag ) over time as it rotates. The first attempts at measuring 2002 MS 4 's rotation were made with
1000-416: A diameter close to 800 km (500 mi), which makes them the largest unnamed objects in the Solar System. 2002 MS 4 is large enough that astronomers consider it a possible dwarf planet . The surface of 2002 MS 4 is dark gray and is composed of water and carbon dioxide ices. 2002 MS 4 has been observed through stellar occultations , which have revealed massive topographic features along
1100-428: A factor of 2–3 compared to the surface-channel CCD. The gate oxide, i.e. the capacitor dielectric , is grown on top of the epitaxial layer and substrate. Later in the process, polysilicon gates are deposited by chemical vapor deposition , patterned with photolithography , and etched in such a way that the separately phased gates lie perpendicular to the channels. The channels are further defined by utilization of
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#17327762302051200-555: A few percent. That image can then be read out slowly from the storage region while a new image is integrating or exposing in the active area. Frame-transfer devices typically do not require a mechanical shutter and were a common architecture for early solid-state broadcast cameras. The downside to the frame-transfer architecture is that it requires twice the silicon real estate of an equivalent full-frame device; hence, it costs roughly twice as much. The interline architecture extends this concept one step further and masks every other column of
1300-429: A full-frame device, all of the image area is active, and there is no electronic shutter. A mechanical shutter must be added to this type of sensor or the image smears as the device is clocked or read out. With a frame-transfer CCD, half of the silicon area is covered by an opaque mask (typically aluminum). The image can be quickly transferred from the image area to the opaque area or storage region with acceptable smear of
1400-447: A function of phase angle, the object's phase curve could be determined, which can reveal the light scattering properties of 2002 MS 4 's surface regolith. In addition to significantly improving the knowledge of 2002 MS 4 's phase curve, the observations by New Horizons also significantly improved the precision of 2002 MS 4 's orbit. 2002 MS 4 has been considered as a possible exploration target for future missions to
1500-592: A gain register is placed between the shift register and the output amplifier. The gain register is split up into a large number of stages. In each stage, the electrons are multiplied by impact ionization in a similar way to an avalanche diode . The gain probability at every stage of the register is small ( P < 2%), but as the number of elements is large (N > 500), the overall gain can be very high ( g = ( 1 + P ) N {\displaystyle g=(1+P)^{N}} ), with single input electrons giving many thousands of output electrons. Reading
1600-492: A gray or spectrally neutral surface color, meaning it reflects similar amounts of light for wavelengths across the visible spectrum . In Barucci et al.'s classification scheme for TNO color indices , 2002 MS 4 falls under the BB group of TNOs with neutral colors, whose surface compositions characteristically have a high fraction of water ice and amorphous carbon but low amounts of tholins . Near-infrared spectroscopy by
1700-401: A large lateral electric field from one gate to the next. This provides an additional driving force to aid in transfer of the charge packets. The CCD image sensors can be implemented in several different architectures. The most common are full-frame, frame-transfer, and interline. The distinguishing characteristic of each of these architectures is their approach to the problem of shuttering. In
1800-399: A non-equilibrium state called deep depletion. Then, when electron–hole pairs are generated in the depletion region, they are separated by the electric field, the electrons move toward the surface, and the holes move toward the substrate. Four pair-generation processes can be identified: The last three processes are known as dark-current generation, and add noise to the image; they can limit
1900-417: A p+ doped region underlying them, providing a further barrier to the electrons in the charge packets (this discussion of the physics of CCD devices assumes an electron transfer device, though hole transfer is possible). The clocking of the gates, alternately high and low, will forward and reverse bias the diode that is provided by the buried channel (n-doped) and the epitaxial layer (p-doped). This will cause
2000-409: A reflective material such as aluminium. When the exposure time is up, the cells are transferred very rapidly to the hidden area. Here, safe from any incoming light, cells can be read out at any speed one deems necessary to correctly measure the cells' charge. At the same time, the exposed part of the CCD is collecting light again, so no delay occurs between successive exposures. The disadvantage of such
2100-445: A signal from a CCD gives a noise background, typically a few electrons. In an EMCCD, this noise is superimposed on many thousands of electrons rather than a single electron; the devices' primary advantage is thus their negligible readout noise. The use of avalanche breakdown for amplification of photo charges had already been described in the U.S. patent 3,761,744 in 1973 by George E. Smith/Bell Telephone Laboratories. EMCCDs show
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#17327762302052200-422: A similar sensitivity to intensified CCDs (ICCDs). However, as with ICCDs, the gain that is applied in the gain register is stochastic and the exact gain that has been applied to a pixel's charge is impossible to know. At high gains (> 30), this uncertainty has the same effect on the signal-to-noise ratio (SNR) as halving the quantum efficiency (QE) with respect to operation with a gain of unity. This effect
2300-416: A single slice of the image, whereas a two-dimensional array, used in video and still cameras, captures a two-dimensional picture corresponding to the scene projected onto the focal plane of the sensor. Once the array has been exposed to the image, a control circuit causes each capacitor to transfer its contents to its neighbor (operating as a shift register). The last capacitor in the array dumps its charge into
2400-417: A spacecraft to 2002 MS 4 over a minimum duration of 18.6–19.5 years. CCD camera In a CCD image sensor , pixels are represented by p-doped metal–oxide–semiconductor (MOS) capacitors . These MOS capacitors , the basic building blocks of a CCD, are biased above the threshold for inversion when image acquisition begins, allowing the conversion of incoming photons into electron charges at
2500-611: A star and blocks out its light, causing the star to dim for several seconds until 2002 MS 4 emerges. Observing stellar occultations by 2002 MS 4 can provide precise measurements for its position, shape, and size. Due to parallax between Earth, 2002 MS 4 , and the occulted star, occultations by 2002 MS 4 may only be observable to certain locations on Earth. For this reason, 2002 MS 4 's orbital trajectory and ephemeris must be precisely known before occultation predictions can be reliably made. To facilitate occultation predictions for 2002 MS 4 , astronomers of
2600-424: A time. During the readout phase, cells are shifted down the entire area of the CCD. While they are shifted, they continue to collect light. Thus, if the shifting is not fast enough, errors can result from light that falls on a cell holding charge during the transfer. These errors are referred to as "vertical smear" and cause a strong light source to create a vertical line above and below its exact location. In addition,
2700-464: A variety of astronomical applications involving low light sources and transient events such as lucky imaging of faint stars, high speed photon counting photometry, Fabry-Pérot spectroscopy and high-resolution spectroscopy. More recently, these types of CCDs have broken into the field of biomedical research in low-light applications including small animal imaging , single-molecule imaging , Raman spectroscopy , super resolution microscopy as well as
2800-543: Is a trans-Neptunian object (TNO) orbiting the Sun beyond Neptune with an orbital period of 269 years. Its semi-major axis or average orbital distance from the Sun is 41.7 astronomical units (AU), with a moderate orbital eccentricity of 0.15. In its eccentric orbit, 2002 MS 4 comes within 35.7 AU from the Sun at perihelion and 47.8 AU at aphelion . It has an orbital inclination of nearly 18° with respect to
2900-410: Is a photoactive region (an epitaxial layer of silicon), and a transmission region made out of a shift register (the CCD, properly speaking). An image is projected through a lens onto the capacitor array (the photoactive region), causing each capacitor to accumulate an electric charge proportional to the light intensity at that location. A one-dimensional array, used in line-scan cameras, captures
3000-432: Is a specialized CCD, often used in astronomy and some professional video cameras , designed for high exposure efficiency and correctness. The normal functioning of a CCD, astronomical or otherwise, can be divided into two phases: exposure and readout. During the first phase, the CCD passively collects incoming photons , storing electrons in its cells. After the exposure time is passed, the cells are read out one line at
3100-447: Is an unknown satellite of 2002 MS 4 contributing to the excess thermal emission, or the predictions for 2002 MS 4 's thermal emission behavior are inaccurate. The mass and density of 2002 MS 4 is unknown since it has no known moons; otherwise, estimation of its mass would have been possible by Kepler's third law . Without a known mass and density, it is not possible to determine whether 2002 MS 4 's spheroidal shape
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3200-474: Is comparable to the largest crater-to-diameter ratios seen in Saturn's moons Tethys and Iapetus . For context, Tethys's largest crater Odysseus takes up about 43% of its diameter, while Iapetus's largest crater Turgis takes up about 40% of its diameter, but they are much shallower than the purported 2002 MS 4 crater. The trans-Neptunian dwarf planets Pluto and Charon do not exhibit such large craters on
3300-441: Is considered a dwarf planet candidate by astronomers. With measurement uncertainties considered, it is tied with 2002 AW 197 and 2013 FY 27 (diameters 729–807 km and 659–820 km , respectively) as the largest unnamed object in the Solar System . 2002 MS 4 was previously thought to have a larger diameter of 934 km (580 mi), according to infrared thermal emission measurements made by
3400-622: Is different from Wikidata All article disambiguation pages All disambiguation pages 2002 MS4 (307261) 2002 MS 4 ( provisional designation 2002 MS 4 ) is a large trans-Neptunian object in the Kuiper belt , which is a region of icy planetesimals beyond Neptune . It was discovered on 18 June 2002 by Chad Trujillo and Michael Brown during their search for bright, Pluto -sized Kuiper belt objects at Palomar Observatory . To within measurement uncertainties, 2002 MS 4 , 2002 AW 197 , and 2013 FY 27 have
3500-465: Is due to hydrostatic equilibrium , which would qualify it as a dwarf planet . Inferring from its diameter and albedo, 2002 MS 4 is probably not in hydrostatic equilibrium since it lies within the 400–1,000 km (250–620 mi) diameter range where TNOs are typically observed with very low densities, presumably due to having highly porous interior structures that have not gravitationally compressed into solid bodies. Otherwise, if 2002 MS 4
3600-512: Is in hydrostatic equilibrium, then its density could be estimated from its oblateness and rotation period. However, both of these properties are poorly known for 2002 MS 4 , so only its minimum and maximum possible densities could be estimated. Assuming a Maclaurin spheroid as the equilibrium shape for 2002 MS 4 , the ranges of possible densities are 0.72–8.0 g/cm and 0.36–3.9 g/cm for possible rotation periods of 7.44 and 10.44 hours, respectively. 2002 MS 4 has
3700-565: Is one of the major advantages of the ICCD over the EMCCD cameras. The highest performing ICCD cameras enable shutter times as short as 200 picoseconds . ICCD cameras are in general somewhat higher in price than EMCCD cameras because they need the expensive image intensifier. On the other hand, EMCCD cameras need a cooling system to cool the EMCCD chip down to temperatures around 170 K (−103 °C ). This cooling system adds additional costs to
3800-564: Is referred to as the Excess Noise Factor (ENF). However, at very low light levels (where the quantum efficiency is most important), it can be assumed that a pixel either contains an electron—or not. This removes the noise associated with the stochastic multiplication at the risk of counting multiple electrons in the same pixel as a single electron. To avoid multiple counts in one pixel due to coincident photons in this mode of operation, high frame rates are essential. The dispersion in
3900-512: Is the probability of getting n output electrons given m input electrons and a total mean multiplication register gain of g . For very large numbers of input electrons, this complex distribution function converges towards a Gaussian. Because of the lower costs and better resolution, EMCCDs are capable of replacing ICCDs in many applications. ICCDs still have the advantage that they can be gated very fast and thus are useful in applications like range-gated imaging . EMCCD cameras indispensably need
4000-422: Is the right choice. Consumer snap-shot cameras have used interline devices. On the other hand, for those applications that require the best possible light collection and issues of money, power and time are less important, the full-frame device is the right choice. Astronomers tend to prefer full-frame devices. The frame-transfer falls in between and was a common choice before the fill-factor issue of interline devices
4100-405: Is used in the construction of interline-transfer devices. Another version of CCD is called a peristaltic CCD. In a peristaltic charge-coupled device, the charge-packet transfer operation is analogous to the peristaltic contraction and dilation of the digestive system . The peristaltic CCD has an additional implant that keeps the charge away from the silicon/ silicon dioxide interface and generates
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4200-543: The New Horizons spacecraft, which indicates 2002 MS 4 has a very dark and unevolved surface in contrast to the bright and volatile-rich dwarf planets like Pluto. New Horizons observations of 2002 MS 4 's phase curve indicate that the icy regolith grains on the object's surface are rough and irregularly shaped. The 8 August 2020 occultation revealed massive topographic features along 2002 MS 4 's northeastern outline, or limb , which notably includes
4300-549: The Spitzer and Herschel space telescopes in 2006 and 2010. This thermal emission-derived diameter disagrees with the occultation-derived diameter; if both the thermal emission measurements and occultation-derived diameter are correct, then 2002 MS 4 would be emitting more thermal radiation than predicted if it were a non-rotating, simple airless body. It is not yet clear why 2002 MS 4 seems to be emitting excess thermal radiation; it could be possible that either there
4400-620: The European Research Council 's Lucky Star project gathered astrometric observations of 2002 MS 4 from 2009–2019 to reduce its orbital uncertainty and utilized the Gaia catalogues for high-precision positions of stars. From 2019 to 2022, the Lucky Star project organized campaigns for astronomers worldwide to observe the predicted occultations by 2002 MS 4 , yielding nine successfully-observed occultations by
4500-481: The James Webb Space Telescope (JWST) in 2022 revealed the presence of crystalline water ice , amorphous water ice , and carbon dioxide ice in 2002 MS 4 's surface. The large Kuiper belt object 120347 Salacia was observed by JWST to have a similar surface composition as 2002 MS 4 . Preliminary modeling of 2002 MS 4 's JWST spectrum by Cook et al. suggests that the water ice on
4600-681: The Kodak Apparatus Division, invented a digital still camera using this same Fairchild 100 × 100 CCD in 1975. The interline transfer (ILT) CCD device was proposed by L. Walsh and R. Dyck at Fairchild in 1973 to reduce smear and eliminate a mechanical shutter . To further reduce smear from bright light sources, the frame-interline-transfer (FIT) CCD architecture was developed by K. Horii, T. Kuroda and T. Kunii at Matsushita (now Panasonic) in 1981. The first KH-11 KENNEN reconnaissance satellite equipped with charge-coupled device array ( 800 × 800 pixels) technology for imaging
4700-566: The LOCOS process to produce the channel stop region. Channel stops are thermally grown oxides that serve to isolate the charge packets in one column from those in another. These channel stops are produced before the polysilicon gates are, as the LOCOS process utilizes a high-temperature step that would destroy the gate material. The channel stops are parallel to, and exclusive of, the channel, or "charge carrying", regions. Channel stops often have
4800-403: The Lucky Star project organized a large observing campaign for 2002 MS 4 , which would occult a relatively bright star of apparent magnitude 14.6 and be observable over densely-populated regions in multiple continents. A total of 116 telescope locations from Europe, North Africa, and Western Asia participated in the campaign and yielded 61 positive detections and 40 negative detections, with
4900-666: The Sierra Nevada Observatory 's 1.5-meter telescope in August 2005, but it did not observe the object long enough to identify any periodicities in its light curve. Subsequent observations by the Galileo National Telescope in June–July 2011 took advantage of 2002 MS 4 passing in front of a dark nebula , which enabled it to determine possible periods of either 7.33 hours or 10.44 hours. On
5000-586: The ecliptic . 2002 MS 4 last passed perihelion in April 1853, passed aphelion in February 1987, and will make its next perihelion passage in June 2123. 2002 MS 4 is located in the classical region of the Kuiper belt 37–48 AU from the Sun, and is thus classified as a classical Kuiper belt object or cubewano. 2002 MS 4 's high orbital inclination qualifies it as a dynamically "hot" member of
5100-458: The excess launch energy of the spacecraft. Another trajectory using a single Jupiter gravity assist for a 2040 launch date could bring a spacecraft to 2002 MS 4 over a minimum duration of 13 years. A 2038–2040 launch trajectory using a single Saturn gravity assist could bring a spacecraft to 2002 MS 4 over a minimum duration of 16.7 years, while a 2038–2040 launch trajectory using two gravity assists from Jupiter and Saturn could bring
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#17327762302055200-473: The photodiode to the CCD. This led to their invention of the pinned photodiode, a photodetector structure with low lag, low noise , high quantum efficiency and low dark current . It was first publicly reported by Teranishi and Ishihara with A. Kohono, E. Oda and K. Arai in 1982, with the addition of an anti-blooming structure. The new photodetector structure invented at NEC was given the name "pinned photodiode" (PPD) by B.C. Burkey at Kodak in 1984. In 1987,
5300-508: The southern celestial hemisphere . It has been passing through that region's dense field of background stars since its discovery. Combined with 2002 MS 4 's faint apparent magnitude of 20.5 as seen from Earth, its crowded location can make observations difficult. On the other hand, 2002 MS 4 's location makes it viable for observing stellar occultations as there are numerous stars for it to pass in front of. Stellar occultations by 2002 MS 4 occur when it passes in front of
5400-399: The CCD cannot be used to collect light while it is being read out. A faster shifting requires a faster readout, and a faster readout can introduce errors in the cell charge measurement, leading to a higher noise level. A frame transfer CCD solves both problems: it has a shielded, not light sensitive, area containing as many cells as the area exposed to light. Typically, this area is covered by
5500-402: The CCD concept. Michael Tompsett was awarded the 2010 National Medal of Technology and Innovation , for pioneering work and electronic technologies including the design and development of the first CCD imagers. He was also awarded the 2012 IEEE Edison Medal for "pioneering contributions to imaging devices including CCD Imagers, cameras and thermal imagers". In a CCD for capturing images, there
5600-545: The CCD to deplete, near the p–n junction and will collect and move the charge packets beneath the gates—and within the channels—of the device. CCD manufacturing and operation can be optimized for different uses. The above process describes a frame transfer CCD. While CCDs may be manufactured on a heavily doped p++ wafer it is also possible to manufacture a device inside p-wells that have been placed on an n-wafer. This second method, reportedly, reduces smear, dark current , and infrared and red response. This method of manufacture
5700-477: The CCD-G5, was released by Sony in 1983, based on a prototype developed by Yoshiaki Hagiwara in 1981. Early CCD sensors suffered from shutter lag . This was largely resolved with the invention of the pinned photodiode (PPD). It was invented by Nobukazu Teranishi , Hiromitsu Shiraki and Yasuo Ishihara at NEC in 1980. They recognized that lag can be eliminated if the signal carriers could be transferred from
5800-404: The EMCCD camera and often yields heavy condensation problems in the application. ICCDs are used in night vision devices and in various scientific applications. An electron-multiplying CCD (EMCCD, also known as an L3Vision CCD, a product commercialized by e2v Ltd., GB, L3CCD or Impactron CCD, a now-discontinued product offered in the past by Texas Instruments) is a charge-coupled device in which
5900-469: The Kuiper belt and beyond, such as NASA's Interstellar Probe concept. A 2019 study by Amanda Zangari and collaborators identified several possible trajectories to 2002 MS 4 for a spacecraft that would be launched in 2025–2040. For a spacecraft launched in 2027–2031, a single gravity assist from Jupiter could bring a spacecraft to 2002 MS 4 over a minimum duration of 9.1–12.8 years, depending on
6000-585: The Minor Planet Center on 10 December 2011. As of yet, it remains unnamed and the discoverers' privilege for naming this object expired ten years after its numbering. Per naming guidelines by the International Astronomical Union 's Working Group for Small Bodies Nomenclature , 2002 MS 4 is open for name suggestions that pertain to creation myths, as required for Kuiper belt objects in general. 2002 MS 4
6100-610: The PPD began to be incorporated into most CCD devices, becoming a fixture in consumer electronic video cameras and then digital still cameras . Since then, the PPD has been used in nearly all CCD sensors and then CMOS sensors . In January 2006, Boyle and Smith were awarded the National Academy of Engineering Charles Stark Draper Prize , and in 2009 they were awarded the Nobel Prize for Physics for their invention of
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#17327762302056200-451: The array's dark current , improving the sensitivity of the CCD to low light intensities, even for ultraviolet and visible wavelengths. Professional observatories often cool their detectors with liquid nitrogen to reduce the dark current, and therefore the thermal noise , to negligible levels. The frame transfer CCD imager was the first imaging structure proposed for CCD Imaging by Michael Tompsett at Bell Laboratories. A frame transfer CCD
6300-426: The channel in which the photogenerated charge packets will travel. Simon Sze details the advantages of a buried-channel device: This thin layer (= 0.2–0.3 micron) is fully depleted and the accumulated photogenerated charge is kept away from the surface. This structure has the advantages of higher transfer efficiency and lower dark current, from reduced surface recombination. The penalty is smaller charge capacity, by
6400-399: The charge could be stepped along from one to the next. This led to the invention of the charge-coupled device by Boyle and Smith in 1969. They conceived of the design of what they termed, in their notebook, "Charge 'Bubble' Devices". The initial paper describing the concept in April 1970 listed possible uses as memory , a delay line, and an imaging device. The device could also be used as
6500-462: The classical Kuiper belt, which implies that it was gravitationally scattered out to its present location by Neptune's outward planetary migration in the Solar System's early history. 2002 MS 4 's present orbit is far enough from Neptune ( minimum orbit intersection distance 6.6 AU) that it no longer experiences scattering from close encounters with the planet. A dynamical study in 2007 simulated 2002 MS 4 's orbital evolution over
6600-589: The end of the period. The first successfully-observed occultation by 2002 MS 4 took place in South America on 9 July 2019, which yielded two positive detections and four negative detections from the 10 participating telescope locations; the remaining four telescopes were affected by poor weather. More successful observations of 2002 MS 4 's occultations took place on 26 July and 19 August 2019, which provided highly precise astrometry that helped refine later occultation predictions. On 8 August 2020,
6700-399: The first time. Results from the extensively observed 8 August 2020 occultation show that 2002 MS 4 has a shape close to that of an oblate spheroid , with an equatorial diameter of 814 km (506 mi) and a polar diameter of up to 770 km (480 mi). 2002 MS 4 's mean diameter from these dimensions is 796 km (495 mi), which places it between the diameters of
6800-819: The gain is shown in the graph on the right. For multiplication registers with many elements and large gains it is well modelled by the equation: P ( n ) = ( n − m + 1 ) m − 1 ( m − 1 ) ! ( g − 1 + 1 m ) m exp ( − n − m + 1 g − 1 + 1 m ) if n ≥ m {\displaystyle P\left(n\right)={\frac {\left(n-m+1\right)^{m-1}}{\left(m-1\right)!\left(g-1+{\frac {1}{m}}\right)^{m}}}\exp \left(-{\frac {n-m+1}{g-1+{\frac {1}{m}}}}\right)\quad {\text{ if }}n\geq m} where P
6900-506: The image sensor for storage. In this device, only one pixel shift has to occur to transfer from image area to storage area; thus, shutter times can be less than a microsecond and smear is essentially eliminated. The advantage is not free, however, as the imaging area is now covered by opaque strips dropping the fill factor to approximately 50 percent and the effective quantum efficiency by an equivalent amount. Modern designs have addressed this deleterious characteristic by adding microlenses on
7000-497: The incident light. Most common types of CCDs are sensitive to near-infrared light, which allows infrared photography , night-vision devices, and zero lux (or near zero lux) video-recording/photography. For normal silicon-based detectors, the sensitivity is limited to 1.1 μm. One other consequence of their sensitivity to infrared is that infrared from remote controls often appears on CCD-based digital cameras or camcorders if they do not have infrared blockers. Cooling reduces
7100-467: The invention and began development programs. Fairchild's effort, led by ex-Bell researcher Gil Amelio, was the first with commercial devices, and by 1974 had a linear 500-element device and a 2D 100 × 100 pixel device. Peter Dillon, a scientist at Kodak Research Labs, invented the first color CCD image sensor by overlaying a color filter array on this Fairchild 100 x 100 pixel Interline CCD starting in 1974. Steven Sasson , an electrical engineer working for
7200-431: The large quality advantage CCDs enjoyed early on has narrowed over time and since the late 2010s CMOS sensors are the dominant technology, having largely if not completely replaced CCD image sensors. The basis for the CCD is the metal–oxide–semiconductor (MOS) structure, with MOS capacitors being the basic building blocks of a CCD, and a depleted MOS structure used as the photodetector in early CCD devices. In
7300-411: The late 1960s, Willard Boyle and George E. Smith at Bell Labs were researching MOS technology while working on semiconductor bubble memory . They realized that an electric charge was the analogy of the magnetic bubble and that it could be stored on a tiny MOS capacitor. As it was fairly straightforward to fabricate a series of MOS capacitors in a row, they connected a suitable voltage to them so that
7400-467: The multiplied electrons back to photons which are guided to the CCD by a fiber optic or a lens. An image intensifier inherently includes a shutter functionality: If the control voltage between the photocathode and the MCP is reversed, the emitted photoelectrons are not accelerated towards the MCP but return to the photocathode. Thus, no electrons are multiplied and emitted by the MCP, no electrons are going to
7500-472: The object was given the minor planet provisional designation of 2002 MS 4 . Since receiving follow-up in August 2002, 2002 MS 4 remained unobserved for more than nine months until it was recovered by Trujillo at Palomar Observatory on 29 May 2003, followed by observations by Wolf Bickel at Bergisch Gladbach Observatory in Germany in June 2003. These recovery observations significantly reduced
7600-571: The object's surface consists of micrometer-sized grains and the carbon dioxide ice consists of a mix of coarser, micrometer-sized grains to finer, sub-micrometer-sized grains. Tholins should also exist on 2002 MS 4 's surface according to Cook et al.'s preliminary model, although they have not been detected in 2002 MS 4 's JWST spectrum. Volatile ices such as methane were also not detected in 2002 MS 4 's JWST spectrum. The lack of volatiles on 2002 MS 4 's surface agrees with its low geometric albedo of 0.1 determined from observations by
7700-453: The observatory's 1.22-meter (48 in) Samuel Oschin telescope with its wide-field CCD camera , which was operated jointly with the nightly Near Earth Asteroid Tracking program at Palomar. This survey was responsible for the discovery of several other large objects beyond Neptune , which includes the dwarf planets Eris , Sedna , and Quaoar . 2002 MS 4 was found through manual vetting of potential moving objects identified by
7800-689: The occultation; this depression feature partially occulted the star as 2002 MS 4 emerged, which resulted in the star brightening gradually instead of instantly. The elevations of these observed topographic features lie beyond the maximum elevation of 6–7 km (3.7–4.3 mi) expected for an icy body of 2002 MS 4 's size, signifying that the object may have experienced a large impact in its past. It would be possible for 2002 MS 4 to support its massive topographic features if its material strength increases toward its core. Topographic features on other TNOs have been previously observed through occultation, such as (208996) 2003 AZ 84 which has
7900-416: The other hand, as their largest crater-to-diameter ratios are 10.5% and 18.9%, respectively. The depth of 2002 MS 4 's massive depression takes up 5.7% of 2002 MS 4 's diameter and exceeds those seen in the largest craters of other Solar System bodies of comparable size: the largest crater of Saturn's moon Mimas has a depth of up to 10–12 km (6.2–7.5 mi) and Vesta's Rheasilvia crater has
8000-598: The other hand, observations by the Canada–France–Hawaii Telescope in July–August 2013 measured a rotation period of 14.251 hours, with other less probable rotation period aliases of 8.932 and 5.881 hours. The New Horizons spacecraft observed 2002 MS 4 during 2016–2019, as part of its extended Kuiper belt mission after its successful Pluto flyby in 2015. 2002 MS 4 was 15.3 AU (2.29 billion km; 1.42 billion mi) away from
8100-413: The other in the mentioned sequence. The photons which are coming from the light source fall onto the photocathode, thereby generating photoelectrons. The photoelectrons are accelerated towards the MCP by an electrical control voltage, applied between photocathode and MCP. The electrons are multiplied inside of the MCP and thereafter accelerated towards the phosphor screen. The phosphor screen finally converts
8200-671: The outline of its shape. These features include a mountain-like peak that is 25 km (16 mi) tall and a crater -like depression that is 320 km (200 mi) wide and 45 km (28 mi) deep. 2002 MS 4 's topographic features are among the tallest and deepest known for Solar System bodies. 2002 MS 4 was discovered on 18 June 2002 by astronomers Chad Trujillo and Michael Brown at Palomar Observatory in San Diego County, California , United States. The discovery formed part their Caltech Wide Area Sky Survey for bright, Pluto -sized Kuiper belt objects using
8300-491: The output of the CCD, and this must be taken into consideration in satellites using CCDs. The photoactive region of a CCD is, generally, an epitaxial layer of silicon . It is lightly p doped (usually with boron ) and is grown upon a substrate material, often p++. In buried-channel devices, the type of design utilized in most modern CCDs, certain areas of the surface of the silicon are ion implanted with phosphorus , giving them an n-doped designation. This region defines
8400-450: The output of the charge amplifier into a low-pass filter), which is then processed and fed out to other circuits for transmission, recording, or other processing. Before the MOS capacitors are exposed to light, they are biased into the depletion region; in n-channel CCDs, the silicon under the bias gate is slightly p -doped or intrinsic. The gate is then biased at a positive potential, above
8500-407: The phosphor screen and no light is emitted from the image intensifier. In this case no light falls onto the CCD, which means that the shutter is closed. The process of reversing the control voltage at the photocathode is called gating and therefore ICCDs are also called gateable CCD cameras. Besides the extremely high sensitivity of ICCD cameras, which enable single photon detection, the gateability
8600-461: The remaining 15 telescopes inhibited by poor weather or technical difficulties. The observers of the occultation found no evidence of rings , cometary jets , or natural satellites around 2002 MS 4 . This is the most extensive participation in a TNO occultation campaign as of 2023 . Thanks to the large amount of positive detections across various locations, the global shape outline and topography of 2002 MS 4 could be seen clearly for
8700-448: The same term This disambiguation page lists articles associated with the same title formed as a letter–number combination. If an internal link led you here, you may wish to change the link to point directly to the intended article. Retrieved from " https://en.wikipedia.org/w/index.php?title=MS4&oldid=1169193699 " Category : Letter–number combination disambiguation pages Hidden categories: Short description
8800-508: The semiconductor-oxide interface; the CCD is then used to read out these charges. Although CCDs are not the only technology to allow for light detection, CCD image sensors are widely used in professional, medical, and scientific applications where high-quality image data are required. In applications with less exacting quality demands, such as consumer and professional digital cameras , active pixel sensors , also known as CMOS sensors (complementary MOS sensors), are generally used. However,
8900-513: The spacecraft when it began observations on 13 July 2016, and was 12.0 AU (1.80 billion km; 1.12 billion mi) away from the spacecraft when it ended observations on 1 September 2019. New Horizons had the unique vantage point of observing 2002 MS 4 and other TNOs while it was inside the Kuiper belt, which allowed the spacecraft to observe these objects at high phase angles (>2°) that are not observable from Earth. By observing how 2002 MS 4 's brightness changes as
9000-406: The surface of the device to direct light away from the opaque regions and on the active area. Microlenses can bring the fill factor back up to 90 percent or more depending on pixel size and the overall system's optical design. The choice of architecture comes down to one of utility. If the application cannot tolerate an expensive, failure-prone, power-intensive mechanical shutter, an interline device
9100-475: The team's automatic image-searching software. It was among the fainter objects detected, just below the survey's limiting magnitude with an observed brightness of magnitude 20.9. Follow-up observations were conducted two months later with Palomar Observatory's 1.52-meter (60 in) telescope on 8 August 2002. The discovery was announced by the Minor Planet Center on 21 November 2002 and
9200-407: The threshold for strong inversion, which will eventually result in the creation of an n channel below the gate as in a MOSFET . However, it takes time to reach this thermal equilibrium: up to hours in high-end scientific cameras cooled at low temperature. Initially after biasing, the holes are pushed far into the substrate, and no mobile electrons are at or near the surface; the CCD thus operates in
9300-456: The total usable integration time. The accumulation of electrons at or near the surface can proceed either until image integration is over and charge begins to be transferred, or thermal equilibrium is reached. In this case, the well is said to be full. The maximum capacity of each well is known as the well depth, typically about 10 electrons per pixel. CCDs are normally susceptible to ionizing radiation and energetic particles which causes noise in
9400-433: The two largest asteroids, Ceres and Vesta . It is unknown whether 2002 MS 4 's equator is being viewed obliquely or edge-on from Earth's perspective, so it is possible that the object's actual polar diameter may be smaller, or have a greater oblateness , than observed in the August 2020 occultation. 2002 MS 4 is the 10th (or 11th if counting Pluto's moon Charon ) largest known TNO. Because of its large size, it
9500-546: The uncertainty of 2002 MS 4 's orbit, allowing for further extrapolation of its position backwards in time for identification in precovery observations. Seven precovery observations from Digitized Sky Survey plates were identified by astronomer Andrew Lowe in 2007; the earliest of these was taken on 8 April 1954 by Palomar Observatory . As of 2023 , 2002 MS 4 has been observed for over 68 years, or about 25% of its orbital period . 2002 MS 4 received its permanent minor planet catalog number of 307261 from
9600-478: Was passing in front or behind 2002 MS 4 during the occultation, but this scenario is unlikely according to Bruno Sicardy, one of the occultation team members. A satellite of this size would not be large enough to explain 2002 MS 4 's excess thermal emission. If 2002 MS 4 's massive depression is a crater, then it would be the first observation of a massive crater on a TNO. The depression's width takes up about 40% of 2002 MS 4 's diameter, which
9700-501: Was a simple 8-bit shift register, reported by Tompsett, Amelio and Smith in August 1970. This device had input and output circuits and was used to demonstrate its use as a shift register and as a crude eight pixel linear imaging device. Development of the device progressed at a rapid rate. By 1971, Bell researchers led by Michael Tompsett were able to capture images with simple linear devices. Several companies, including Fairchild Semiconductor , RCA and Texas Instruments , picked up on
9800-479: Was addressed. Today, frame-transfer is usually chosen when an interline architecture is not available, such as in a back-illuminated device. CCDs containing grids of pixels are used in digital cameras , optical scanners , and video cameras as light-sensing devices. They commonly respond to 70 percent of the incident light (meaning a quantum efficiency of about 70 percent) making them far more efficient than photographic film , which captures only about 2 percent of
9900-450: Was demonstrated by Gil Amelio , Michael Francis Tompsett and George Smith in April 1970. This was the first experimental application of the CCD in image sensor technology, and used a depleted MOS structure as the photodetector. The first patent ( U.S. patent 4,085,456 ) on the application of CCDs to imaging was assigned to Tompsett, who filed the application in 1971. The first working CCD made with integrated circuit technology
10000-471: Was launched in December 1976. Under the leadership of Kazuo Iwama , Sony started a large development effort on CCDs involving a significant investment. Eventually, Sony managed to mass-produce CCDs for their camcorders . Before this happened, Iwama died in August 1982. Subsequently, a CCD chip was placed on his tombstone to acknowledge his contribution. The first mass-produced consumer CCD video camera ,
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