Super-Kamiokande is a neutrino observatory located under Mount Ikeno near the city of Hida, Gifu Prefecture, Japan. It is located 1,000 m underground in the Mozumi Mine in Hida's Kamioka area; the observatory was designed to detect high-energy neutrinos, to search for proton decay, study solar and atmospheric neutrinos, keep watch for supernovae in the Milky Way Galaxy. It consists of a cylindrical stainless steel tank about 40 m in height and diameter holding 50,000 tons of ultrapure water. Mounted on an inside superstructure are about 13,000 photomultiplier tubes that detect light from Cherenkov radiation. A neutrino interaction with the electrons of nuclei of water can produce an electron or positron that moves faster than the speed of light in water, lower than the speed of light in a vacuum; this creates a cone of Cherenkov radiation light, the optical equivalent to a sonic boom. The Cherenkov light is recorded by the photomultiplier tube. Using the information recorded by each tube, the direction and flavor of the incoming neutrino is determined.
The Super-K is located 1,000 m underground in the Mozumi Mine in Hida's Kamioka area. It consists of a cylindrical stainless steel tank, 41.4 m tall and 39.3 m in diameter holding 50,000 tons of ultrapure water. The tank volume is divided by a stainless steel superstructure into an inner detector region, 36.2 m in height and 33.8 m in diameter, outer detector which consists of the remaining tank volume. Mounted on the superstructure are 11,146 photomultiplier tubes 50 cm in diameter that face the ID and 1,885 20 cm PMTs that face the OD. There is a Tyvek and blacksheet barrier attached to the superstructure that optically separates the ID and OD. A neutrino interaction with the electrons or nuclei of water can produce a charged particle that moves faster than the speed of light in water, slower than the speed of light in a vacuum; this creates a cone of light known as Cherenkov radiation, the optical equivalent to a sonic boom. The Cherenkov light is recorded by the PMTs. Using the timing and charge information recorded by each PMT, the interaction vertex, ring direction and flavor of the incoming neutrino is determined.
From the sharpness of the edge of the ring the type of particle can be inferred. The multiple scattering of electrons is large, so electromagnetic showers produce fuzzy rings. Relativistic muons, in contrast, travel straight through the detector and produce rings with sharp edges. Construction of the predecessor of the present Kamioka Observatory, the Institute for Cosmic Ray Research, University of Tokyo began in 1982 and was completed in April 1983; the purpose of the observatory was to detect whether proton decay exists, one of the most fundamental questions of elementary particle physics. The detector, named KamiokaNDE for Kamioka Nucleon Decay Experiment, was a tank 16.0 m in height and 15.6 m in width, containing 3,048 metric tons of pure water and about 1,000 photomultiplier tubes attached to its inner surface. The detector was upgraded, starting in 1985; as a result, the detector had become sensitive enough to detect neutrinos from SN 1987A, a supernova, observed in the Large Magellanic Cloud in February 1987, to observe solar neutrinos in 1988.
The ability of the Kamiokande experiment to observe the direction of electrons produced in solar neutrino interactions allowed experimenters to directly demonstrate for the first time that the sun was a source of neutrinos. The Super-Kamiokande project was approved by the Japanese Ministry of Education, Science and Culture in 1991 for total funding of $100 M; the US portion of the proposal, to build the OD system, was approved by the US Department of Energy in 1993 for $3 M. In addition the US has contributed about 2000 20 cm PMTs recycled from the IMB experiment. Despite successes in neutrino astronomy and neutrino astrophysics, Kamiokande did not achieve its primary goal, the detection of proton decay. Higher sensitivity was necessary to obtain high statistical confidence in its results; this led to the construction of Super-Kamiokande, with fifteen times the water and ten times as many PMTs as Kamiokande. Super-Kamiokande started operation in 1996; the Super-Kamiokande Collaboration announced the first evidence of neutrino oscillation in 1998.
This was the first experimental observation supporting the theory that the neutrino has non-zero mass, a possibility that theorists had speculated about for years. The 2015 Nobel Prize in Physics was awarded to Super-Kamiokande researcher Takaaki Kajita alongside Arthur McDonald for their work on neutrino oscillations. On 12 November 2001, about 6,600 of the photomultiplier tubes in the Super-Kamiokande detector imploded in a chain reaction or cascading failure, as the shock wave from the concussion of each imploding tube cracked its neighbours; the detector was restored by redistributing the photomultiplier tubes which did not implode, by adding protective acrylic shells that are hoped will prevent another chain reaction from recurring. In July 2005, preparations began to restore the detector to its original form by reinstalling about 6,000 PMTs; the work was completed in June 2006, whereupon the detector was renamed Super-Kamiokande-III. This phase of the experiment collected data from October 2006 till August 2008.
At that time, significant upgrades were made to th
An RF module is a small electronic device used to transmit and/or receive radio signals between two devices. In an embedded system it is desirable to communicate with another device wirelessly; this wireless communication may be accomplished through optical communication or through radio-frequency communication. For many applications, the medium of choice is RF. RF communications incorporate a receiver, they are of various ranges. Some can transmit up to 500 feet. RF modules are fabricated using RF CMOS technology. RF modules are used in electronic design owing to the difficulty of designing radio circuitry. Good electronic radio design is notoriously complex because of the sensitivity of radio circuits and the accuracy of components and layouts required to achieve operation on a specific frequency. In addition, reliable RF communication circuit requires careful monitoring of the manufacturing process to ensure that the RF performance is not adversely affected. Radio circuits are subject to limits on radiated emissions, require Conformance testing and certification by a standardization organization such as ETSI or the U.
S. Federal Communications Commission. For these reasons, design engineers will design a circuit for an application which requires radio communication and "drop in" a pre-made radio module rather than attempt a discrete design, saving time and money on development. RF modules are most used in medium and low volume products for consumer applications such as garage door openers, wireless alarm or monitoring systems, industrial remote controls, smart sensor applications, wireless home automation systems, they are sometimes used to replace older infrared communication designs as they have the advantage of not requiring line-of-sight operation. Several carrier frequencies are used in commercially available RF modules, including those in the industrial and medical radio bands such as 433.92 MHz, 915 MHz, 2400 MHz. These frequencies are used because of national and international regulations governing the used of radio for communication. Short Range Devices may use frequencies available for unlicensed such as 315 MHz and 868 MHz.
RF modules may comply with a defined protocol for RF communications such as Zigbee, Bluetooth Low Energy, or Wi-Fi, or they may implement a proprietary protocol. The term RF module can be applied to many different types and sizes of small electronic sub assembly circuit board, it can be applied to modules across a huge variation of functionality and capability. RF modules incorporate a printed circuit board, transmit or receive circuit and serial interface for communication to the host processor. Most standard, well known types are covered here: transmitter module receiver module transceiver module system on a chip module. An RF transmitter module is a small PCB sub-assembly capable of transmitting a radio wave and modulating that wave to carry data. Transmitter modules are implemented alongside a microcontroller which will provide data to the module which can be transmitted. RF transmitters are subject to regulatory requirements which dictate the maximum allowable transmitter power output and band edge requirements.
An RF receiver module receives the modulated RF signal, demodulates it. There are two types of RF receiver modules: superheterodyne receivers and superregenerative receivers. Superregenerative modules are low cost and low power designs using a series of amplifiers to extract modulated data from a carrier wave. Superregenerative modules are imprecise as their frequency of operation varies with temperature and power supply voltage. Superheterodyne receivers have a performance advantage over superregenerative; this stability comes from a fixed crystal design which in the past tended to mean a comparatively more expensive product. However, advances in receiver chip design now mean that there is little price difference between superheterodyne and superregenerative receiver modules. An RF transceiver module incorporates both receiver; the circuit is designed for half-duplex operation, although full-duplex modules are available at a higher cost due to the added complexity. An SoC module is the same as a transceiver module, but it is made with an onboard microcontroller.
The microcontroller is used to handle radio data packetisation or managing a protocol such as an IEEE 802.15.4 compliant module. This type of module is used for designs that require additional processing for compliance with a protocol when the designer does not wish to incorporate this processing into the host microcontroller. RF modules communicate with an embedded system, such as a microcontroller or a microprocessor; the communication protocols include UART, used in Digi International's X-Bee modules, Serial Peripheral Interface Bus used in Anaren's AIR modules and Universal Serial Bus used in Roving Networks' modules. Although the module may use a standardized protocol for wireless communication, the commands sent over the microcontroller interface are not standardized as each vendor has its own proprietary communications format; the speed of the microcontroller interface depends on the speed of the underlying RF protocol used: higher speed RF protocols such as Wi-Fi require a high-speed serial interface such as USB whereas protocols with a slower data rate such as Bluetooth Low Energy may use a UART interface.
There are several types of signal modulation methods used in RF
Ehud "Udi" Dekel is a former Israeli army brigadier general. He was head of the Planning Directorate of the Israel Defense Forces and is now deputy director of the Institute for National Security Studies. Dekel's military career began in the Israeli Air Force, he headed the Air Intelligence Group in the mid 1990s and was chief of the External Relations Division of the IDF. He served as the IAF's representative in peace negotiations with the Palestinians. Prime Minister Ehud Olmert appointed Dekel to lead the Israeli negotiating team in the peace talks that followed the Annapolis Conference in early 2008, he helped formulate Israeli positions in negotiations. Since leaving government, Dekel has served in Track II diplomacy under the auspices of the S. Daniel Abraham Center for Strategic Dialogue at Netanya Academic College and funded by the European Union, his working group, composed of Israelis and Jordanians, is studying the regional security implications of creating a Palestinian state. Dekel is a researcher at the Jerusalem Center for Public Affairs.