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51-459: Around 1968 Sheldon Glashow , Steven Weinberg , and Abdus Salam came up with the electroweak theory , which unified electromagnetism and weak interactions , and for which they shared the 1979 Nobel Prize in Physics . The theory postulated the existence of W and Z bosons, and the pressure on the research community to prove the existence of these particles experimentally was substantial. During

102-680: A NSF fellow at NORDITA and met Murray Gell-Mann , who convinced him to become a research fellow at the California Institute of Technology . Glashow then became an assistant professor at Stanford University before joining the University of California, Berkeley where he was an associate professor from 1962 to 1966. He joined the Harvard physics department as a professor in 1966, and was named Eugene Higgins Professor of Physics in 1979; he became emeritus in 2000. Glashow has been

153-447: A certain distance, and where the metal gate is replaced by an ion -sensitive membrane , electrolyte solution and reference electrode . The ISFET is widely used in biomedical applications, such as the detection of DNA hybridization , biomarker detection from blood , antibody detection, glucose measurement, pH sensing, and genetic technology . By the mid-1980s, numerous other MOSFET sensors had been developed, including

204-471: A digital signal, using an analog-to-digital converter . Since sensors cannot replicate an ideal transfer function , several types of deviations can occur which limit sensor accuracy : All these deviations can be classified as systematic errors or random errors . Systematic errors can sometimes be compensated for by means of some kind of calibration strategy. Noise is a random error that can be reduced by signal processing , such as filtering, usually at

255-510: A more limited scope. UA2 was optimized for the detection of electrons from W and Z decays . The emphasis was on a highly granular calorimeter – a detector measuring how much energy particles deposit – with spherical projective geometry, which also was well adapted to the detection of hadronic jets . Charged particle tracking was performed in the central detector utilising a combination of multi-wire proportional chambers and drift chambers and hodoscopes . Energy measurements were performed in

306-480: A sharp distinction between a biosensor and a standard chemical sensor is superfluous. Typical biomimetic materials used in sensor development are molecularly imprinted polymers and aptamers . In biomedicine and biotechnology , sensors which detect analytes thanks to a biological component, such as cells, protein, nucleic acid or biomimetic polymers , are called biosensors . Whereas a non-biological sensor, even organic (carbon chemistry), for biological analytes

357-420: A thermometer moves 1  cm when the temperature changes by 1 °C, its sensitivity is 1 cm/°C (it is basically the slope dy/dx assuming a linear characteristic). Some sensors can also affect what they measure; for instance, a room temperature thermometer inserted into a hot cup of liquid cools the liquid while the liquid heats the thermometer. Sensors are usually designed to have a small effect on what

408-487: A top quark mass value in the range of 110 GeV to 220 GeV, beyond the reach for direct detection by UA2 at the Sp p S. The top quark was ultimately discovered in 1995 by physicists at Fermilab with a mass near 175 GeV. Sheldon Glashow Sheldon Lee Glashow ( US : / ˈ ɡ l æ ʃ oʊ / , UK : / ˈ ɡ l æ ʃ aʊ / ; born December 5, 1932) is a Nobel Prize -winning American theoretical physicist . He

459-410: A visiting scientist at CERN , and professor at Aix-Marseille University , MIT , Brookhaven Laboratory , Texas A&M , the University of Houston , and Boston University . In 1961, Glashow extended electroweak unification models due to Schwinger by including a short range neutral current , the Z . The resulting symmetry structure that Glashow proposed, SU(2) × U(1) , forms the basis of

510-400: A wide range of other sensors that measure chemical and physical properties of materials, including optical sensors for refractive index measurement, vibrational sensors for fluid viscosity measurement, and electro-chemical sensors for monitoring pH of fluids. A sensor's sensitivity indicates how much its output changes when the input quantity it measures changes. For instance, if the mercury in

561-438: Is a self-contained analytical device that can provide information about the chemical composition of its environment, that is, a liquid or a gas phase . The information is provided in the form of a measurable physical signal that is correlated with the concentration of a certain chemical species (termed as analyte ). Two main steps are involved in the functioning of a chemical sensor, namely, recognition and transduction . In

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612-739: Is measured; making the sensor smaller often improves this and may introduce other advantages. Technological progress allows more and more sensors to be manufactured on a microscopic scale as microsensors using MEMS technology. In most cases, a microsensor reaches a significantly faster measurement time and higher sensitivity compared with macroscopic approaches. Due to the increasing demand for rapid, affordable and reliable information in today's world, disposable sensors—low-cost and easy‐to‐use devices for short‐term monitoring or single‐shot measurements—have recently gained growing importance. Using this class of sensors, critical analytical information can be obtained by anyone, anywhere and at any time, without

663-403: Is referred to as sensor or nanosensor . This terminology applies for both in-vitro and in vivo applications. The encapsulation of the biological component in biosensors, presents a slightly different problem that ordinary sensors; this can either be done by means of a semipermeable barrier , such as a dialysis membrane or a hydrogel , or a 3D polymer matrix, which either physically constrains

714-721: Is the Metcalf Professor of Mathematics and Physics at Boston University and Eugene Higgins Professor of Physics, emeritus, at Harvard University , and is a member of the board of sponsors for the Bulletin of the Atomic Scientists . Sheldon Glashow was born on December 5, 1932, in New York City , to Jewish immigrants from Russia , Bella (née Rubin) and Lewis Gluchovsky, a plumber. He graduated from Bronx High School of Science in 1950. Glashow

765-570: Is the basis for modern image sensors , including the charge-coupled device (CCD) and the CMOS active-pixel sensor (CMOS sensor), used in digital imaging and digital cameras . Willard Boyle and George E. Smith developed the CCD in 1969. While researching the MOS process, 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

816-514: The GIM mechanism showed that the two quark pairs: (d.s), (u,c), would largely cancel out flavor changing neutral currents, which had been observed experimentally at far lower levels than theoretically predicted on the basis of 3 quarks only. The prediction of the charm quark also removed a technical disaster for any quantum field theory with unequal numbers of quarks and leptons — an anomaly — where classical field theory symmetries fail to carry over into

867-534: The gas sensor FET (GASFET), surface accessible FET (SAFET), charge flow transistor (CFT), pressure sensor FET (PRESSFET), chemical field-effect transistor (ChemFET), reference ISFET (REFET), biosensor FET (BioFET), enzyme-modified FET (ENFET) and immunologically modified FET (IMFET). By the early 2000s, BioFET types such as the DNA field-effect transistor (DNAFET), gene-modified FET (GenFET) and cell-potential BioFET (CPFET) had been developed. MOS technology

918-401: The 70s it was established that the masses of the W and Z bosons were in the range of 60 to 80 GeV (W boson) and 75 to 92 GeV (Z boson) — energies too large to be accessible by any accelerator in operation at that time. In 1976, Carlo Rubbia , Peter McIntyre and David Cline proposed to modify a proton accelerator — at that time a proton accelerator was already running at Fermilab and one

969-525: The SPS could revert to fixed-target operation. UA2 was moved on air cushions when removed from the beam pipe of the Sp p S. The UA2 experiment was located some 50 meters underground, in the ring of the SPS / Sp p S accelerator, and was housed in a big cavern. The cavern was large enough to house the detector, provide room for it to be assembled in a "garage position" without shutting down the accelerator and to where it

1020-579: The UA1 and UA2 experiments collected data corresponding to an integrated luminosity of approximately 0.9  pb . From 1985 to 1987 the Sp p S was upgraded, and the luminosity of the machine increased by a factor 10 compared to the previous performance. The UA2 sub-detectors were also upgraded, making the detector hermetic, which increased its ability to measure missing transverse energy. The second experimental phase ran from 1987 to 1990. Groups from Cambridge , Heidelberg , Milano , Perugia and Pisa joined

1071-515: The UA2 collaboration announced that the UA2 detector had recorded four events that were candidates for a W boson. This brought the combined number of candidate events seen by UA1 and UA2 up to 10. Three days later, CERN made a public announcement that the W boson was found. The next step was to track down the Z boson. However, the theory said that the Z boson would be ten times rarer than the W boson. The experiments therefore needed to collect several times

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1122-455: The US in the search for the top quark . Physicists had anticipated its existence since 1977, when its partner — the bottom quark — was discovered. It was felt that the discovery of the top quark was imminent. During the 1987-1990 run UA2 collected 2065 W → e ν {\displaystyle W\rightarrow e\nu } decays, and 251 Z decays to electron pairs, from which

1173-418: The accepted theory of the electroweak interactions. For this discovery, Glashow along with Steven Weinberg and Abdus Salam , was awarded the 1979 Nobel Prize in Physics . In collaboration with James Bjorken , Glashow was the first to predict a fourth quark, the charm quark , in 1964. This was at a time when 4 leptons had been discovered but only 3 quarks proposed. The development of their work in 1970,

1224-510: The broadest definition, a sensor is a device, module, machine, or subsystem that detects events or changes in its environment and sends the information to other electronics, frequently a computer processor. Sensors are used in everyday objects such as touch-sensitive elevator buttons ( tactile sensor ) and lamps which dim or brighten by touching the base, and in innumerable applications of which most people are never aware. With advances in micromachinery and easy-to-use microcontroller platforms,

1275-424: The calorimeters. Unlike UA1, UA2 had no muon detector. The calorimeter had 24 slices, each weighing 4 tons. These slices were arranged around the collision point like segments of an orange. Particles ejected from the collision produced showers of secondary particles in the layers of heavy material. These showers passed through layers of plastic scintillators, generating light which was read with photomultiplier by

1326-480: The campaign failed. About ten minutes into "String's the Thing", the second episode of The Elegant Universe TV series, he describes superstring theory as a discipline distinct from physics, saying "...you may call it a tumor, if you will...". Glashow is married to Joan Shirley Alexander. They have four children. Lynn Margulis was Joan's sister, making Carl Sagan his former brother-in-law. Daniel Kleitman , who

1377-430: The collaboration, which grew to about 100 physicists. During this phase, UA2 accumulated data corresponding to an integrated luminosity of 13.0 pb in three major running periods. After nearly ten years of operation, the UA2 experimental program stopped running at the end of 1990. The UA1 and UA2 experiments recorded data during proton–antiproton collision operation and moved back after periods of data taking, so that

1428-682: The damage done to basic science research in the Fiscal Year 2008 Omnibus Appropriations Bill" by requesting additional emergency funding for the Department of Energy ’s Office of Science , the National Science Foundation , and the National Institute of Standards and Technology . Detector A sensor is a device that produces an output signal for the purpose of detecting a physical phenomenon. In

1479-408: The data collected in the 1982 run that showed the existence of the W boson. With improved techniques and methods, the luminosity was increased substantially. These efforts were successful, and on 1 June 1983, the formal announcement of the discovery of the Z boson was made at CERN. Throughout the runs with the upgraded detector, the UA2 collaboration was in competition with experiments at Fermilab in

1530-402: The data collection electronics. The amount of light was proportional to the energy of the original particle. Accurate calibration of the central calorimeter allowed the W and Z masses to be measured with a precision of about 1%. The 1985-1987 upgrade of the detector was aimed at two aspects: full calorimeter coverage and better electron identification at lower transverse momenta. The first aspect

1581-499: The expense of the dynamic behavior of the sensor. The sensor resolution or measurement resolution is the smallest change that can be detected in the quantity that is being measured. The resolution of a sensor with a digital output is usually the numerical resolution of the digital output. The resolution is related to the precision with which the measurement is made, but they are not the same thing. A sensor's accuracy may be considerably worse than its resolution. A chemical sensor

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1632-561: The gross features of the strong parton interaction . The UA2 and UA1 collaboration chose to search for the W boson by identifying its leptonic decay, because the hadronic decays, although more frequent, have a larger background. By the end 1982, the Sp p S had reached high enough luminosity to permit the observation of W → e ν {\displaystyle W\rightarrow e\nu } and W → μ ν {\displaystyle W\rightarrow \mu \nu } decays. On 22 January 1983,

1683-409: The need for recalibration and worrying about contamination. A good sensor obeys the following rules: Most sensors have a linear transfer function . The sensitivity is then defined as the ratio between the output signal and measured property. For example, if a sensor measures temperature and has a voltage output, the sensitivity is constant with the units [V/K]. The sensitivity is the slope of

1734-406: The open-gate field-effect transistor (OGFET) introduced by Johannessen in 1970, the ion-sensitive field-effect transistor (ISFET) invented by Piet Bergveld in 1970, the adsorption FET (ADFET) patented by P.F. Cox in 1974, and a hydrogen -sensitive MOSFET demonstrated by I. Lundstrom, M.S. Shivaraman, C.S. Svenson and L. Lundkvist in 1975. The ISFET is a special type of MOSFET with a gate at

1785-464: The quantum theory. In 1973, Glashow and Howard Georgi proposed the first grand unified theory . They discovered how to fit the gauge forces in the standard model into an SU(5) Lie group group, and the quarks and leptons into two simple representations. Their theory qualitatively predicted the general pattern of coupling constant running, with plausible assumptions, it gave rough mass ratio values between third generation leptons and quarks, and it

1836-421: The ratio of the mass of the W boson and the mass of the Z boson could be measured with a precision of 0.5%. By 1991 a precise measurement for the mass of the Z boson from LEP had become available. Using the ratio of the W mass to Z mass, a first precise measurement of the W mass could be made. These mass values could be used to predict the top quark from its virtual effect on the W mass. The result of this study gave

1887-521: The recognition step, analyte molecules interact selectively with receptor molecules or sites included in the structure of the recognition element of the sensor. Consequently, a characteristic physical parameter varies and this variation is reported by means of an integrated transducer that generates the output signal. A chemical sensor based on recognition material of biological nature is a biosensor . However, as synthetic biomimetic materials are going to substitute to some extent recognition biomaterials,

1938-590: The same purpose as UA1, were made the same year. On 14 December 1978, the proposal of Pierre Darriulat , Luigi Di Lella and collaborators, was approved. Like UA1 , UA2 was a moveable detector, custom built around the beam pipe of the collider, which searched proton–antiproton collisions for signatures of the W and Z particles. The UA2 experiment began operating in December 1981. The initial UA2 collaboration consisted of about 60 physicists from Bern , CERN, Copenhagen , Orsay , Pavia and Saclay . From 1981 to 1985,

1989-665: The sensing macromolecule or chemically constrains the macromolecule by bounding it to the scaffold. Neuromorphic sensors are sensors that physically mimic structures and functions of biological neural entities. One example of this is the event camera . The MOSFET invented at Bell Labs between 1955 and 1960, MOSFET sensors (MOS sensors) were later developed, and they have since been widely used to measure physical , chemical , biological and environmental parameters. A number of MOSFET sensors have been developed, for measuring physical , chemical , biological , and environmental parameters. The earliest MOSFET sensors include

2040-459: The transfer function. Converting the sensor's electrical output (for example V) to the measured units (for example K) requires dividing the electrical output by the slope (or multiplying by its reciprocal). In addition, an offset is frequently added or subtracted. For example, −40 must be added to the output if 0 V output corresponds to −40 C input. For an analog sensor signal to be processed or used in digital equipment, it needs to be converted to

2091-401: The uses of sensors have expanded beyond the traditional fields of temperature, pressure and flow measurement, for example into MARG sensors . Analog sensors such as potentiometers and force-sensing resistors are still widely used. Their applications include manufacturing and machinery, airplanes and aerospace, cars, medicine, robotics and many other aspects of our day-to-day life. There is

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2142-420: Was addressed by replacing the end-caps with new calorimeters that covered the regions 6°-40° with respect to the beam direction, thereby hermetically sealing the detector. The end-cap calorimeters consisted of lead/ scintillator samplings for the electromagnetic part, and iron/scintillator for the hadronic part. The performance and granularity of the new calorimeters were set to match the central calorimeter, which

2193-431: Was also moved back after periods of data taking. The accelerator could therefore revert to fixed-target operation, after periods of operating as a collider. The UA1 and the UA2 experiments had many things in common; they were both operating on the same accelerator and both had the same objective (to discover the W and Z bosons ). The main difference was the detector design; UA1 was a multipurpose detector , while UA2 had

2244-620: Was another doctoral student of Julian Schwinger , is also his brother-in-law, through Joan's other sister, Sharon. In 2003, he was one of 22 Nobel Laureates who signed the Humanist Manifesto . Glashow has described himself as a "practising atheist " and a Democrat. Glashow is one of the 20 American recipients of the Nobel Prize in Physics to sign a letter addressed to President George W. Bush in May 2008, urging him to "reverse

2295-520: Was built as a cylinder, closely surrounding the beam pipe. The detector had to fit into the available space of less than 1 cm. It was therefore necessary to miniaturize the components of the detector. This was achieved with two brand new technologies: the silicon sensor and the Application Specific Integrated Circuit (ASIC). Existing electronics were too bulky, and therefore a novel ASIC had to be developed. This

2346-431: Was fairly straightforward to fabricate a series of MOS capacitors in a row, they connected a suitable voltage to them so that the charge could be stepped along from one to the next. The CCD is a semiconductor circuit that was later used in the first digital video cameras for television broadcasting . The MOS active-pixel sensor (APS) was developed by Tsutomu Nakamura at Olympus in 1985. The CMOS active-pixel sensor

2397-483: Was in the same graduating class as Steven Weinberg , whose own research, independent of Glashow's, would result in Glashow, Weinberg, and Abdus Salam sharing the 1979 Nobel Prize in Physics (see below). Glashow received a Bachelor of Arts degree from Cornell University in 1954 and a PhD degree in physics from Harvard University in 1959 under Nobel-laureate physicist Julian Schwinger . Afterwards, Glashow became

2448-417: Was of importance for the triggering system. The electron identification was improved by the use of a completely new central tracking detector assembly, partly consisting of a pioneering silicone-pad detector. In 1989, the collaboration pushed this concept even further by developing a Silicon Pad Detector (SPD) with finer pad segmentation to be placed directly around the collision region beam pipe. This detector

2499-493: Was the first indication that the law of Baryon number is inexact, that the proton is unstable. This work was the foundation for all future unifying work. Glashow shared the 1977 J. Robert Oppenheimer Memorial Prize with Feza Gürsey . Glashow is a skeptic of superstring theory due to its lack of experimentally testable predictions. He had campaigned to keep string theorists out of the Harvard physics department, though

2550-414: Was the first silicon tracker adapted to a collider experiment, a technology prior to the present silicon detectors. The very first result of the UA2 collaboration, published on 2 December 1982, was the first unambiguous observation of hadronic jet production at high transverse momentum from hadronic collisions. Observations of hadronic jets confirmed that the theory of quantum chromodynamics could describe

2601-526: Was under construction at CERN (SPS) — into a proton – antiproton collider, able to reach energies large enough to produce W and Z bosons. The proposal was adopted at CERN in 1978, and the Super Proton Synchrotron (SPS) was modified to occasionally operate as a proton-antiproton collider (Sp p S). On 29 June 1978 the UA1 experiment was approved. Two proposals for a second detector, with

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