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43-499: Thomas Jefferson National Accelerator Facility ( TJNAF ), commonly called Jefferson Lab or JLab , is a US Department of Energy National Laboratory located in Newport News, Virginia . Since June 1, 2006, it has been operated by Jefferson Science Associates, LLC, a limited liability company created by  Southeastern Universities Research Association  and PAE Applied Technologies. Since 2021, Jefferson Science Association has been

86-434: A fourth experimental hall area started. The plans progressed through various DOE Critical Decision-stages in the 2000s decade, with the final DOE acceptance in 2008 and the construction on the 12 GeV upgrade beginning in 2009. May 18, 2012 the original 6 GeV CEBAF accelerator shut down for the replacement of the accelerator components for the 12 GeV upgrade. 178 experiments were completed with the original CEBAF. In addition to

129-553: A wholly owned subsidiary of Southeastern Universities Research Association. Until 1996 TJNAF was known as the Continuous Electron Beam Accelerator Facility (CEBAF); commonly, this name is still used for the main accelerator. Founded in 1984, Jefferson Lab employs more than 750 people, and more than 2,000 scientists from around the world have conducted research using the facility. The facility was established in 1984 (first initial funding by

172-412: Is a fermion and at very low temperatures, they form two-atom Cooper pairs which are bosonic and condense into a superfluid . These Cooper pairs are substantially larger than the interatomic separation. The temperature required to produce liquid helium is low because of the weakness of the attractions between the helium atoms. These interatomic forces in helium are weak to begin with because helium

215-414: Is a linear accelerator , similar to SLAC at Stanford , that has been folded up to a tenth of its normal length. The design of CEBAF allows the electron beam to be continuous rather than the pulsed beam typical of ring shaped accelerators. (There is some beam structure, but the pulses are very much shorter and closer together.) The electron beam is directed onto three potential targets (see below). One of

258-474: Is a noble gas , but the interatomic attractions are reduced even more by the effects of quantum mechanics . These are significant in helium because of its low atomic mass of about four atomic mass units . The zero point energy of liquid helium is less if its atoms are less confined by their neighbors. Hence in liquid helium, its ground state energy can decrease by a naturally occurring increase in its average interatomic distance. However at greater distances,

301-497: Is a set of software tools and recommended hardware that facilitates a data acquisition system for nuclear physics experiments. In nuclear and particle physics experiments, the particle tracks are digitized by the data acquisition system, but the detectors are capable of generating a large number of possible measurements, or "data channels". Typically, the ADC, TDC, and other digital electronics are large circuit boards with connectors at

344-463: Is gathered and stored so that the physicist can later analyze the data and reconstruct the physics that occurred. The system of electronics and computers that perform this task is called a data acquisition system . As of June 2010, construction began on a $ 338 million upgrade to add an end station, Hall D, on the opposite end of the accelerator from the other three halls, as well as to double beam energy to 12 GeV. Concurrently, an addition to

387-399: Is present: the common isotope helium-4 or the rare isotope helium-3 . These are the only two stable isotopes of helium. See the table below for the values of these physical quantities. The density of liquid helium-4 at its boiling point and a pressure of one atmosphere (101.3 kilopascals ) is about 125 g/L (0.125 g/ml), or about one-eighth the density of liquid water . Helium

430-729: The Department of Energy ) as the Continuous Electron Beam Accelerator Facility (CEBAF) by the Southeastern Universities Research Association; the name was changed to Thomas Jefferson National Accelerator Facility in 1996. The full funding for construction was appropriated by US Congress in 1986 and on February 13, 1987, the construction of the main component, the CEBAF accelerator began. The first beam

473-959: The National Defense Research Committee , and later the Office of Scientific Research and Development , organized and administered by Vannevar Bush . During the Second World War, centralized sites such as the Radiation Laboratory at MIT and Ernest O. Lawrence 's laboratory at Berkeley and the Metallurgical Laboratory at the University of Chicago allowed for a large number of expert scientists to collaborate towards defined goals as never before, and with government resources of unprecedented scale at their disposal. In

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516-452: The physical sciences . Liquid helium Liquid helium is a physical state of helium at very low temperatures at standard atmospheric pressures . Liquid helium may show superfluidity . At standard pressure, the chemical element helium exists in a liquid form only at the extremely low temperature of −269 °C (−452.20 °F; 4.15 K). Its boiling point and critical point depend on which isotope of helium

559-418: The CEBAF 12 GeV Upgrade Dedication Ceremony took place. As of December 2018, the CEBAF accelerator delivered electron beams to all four experimental halls simultaneously for physics-quality production running. A technical full description of the accelerator upgrade and subsequent performance appeared in 2024. Jefferson Lab conducts a broad program of research using the electromagnetic interaction to probe

602-472: The CODA system, each chassis contains a board that is an intelligent controller for the rest of the chassis. This board, called a ReadOut Controller (ROC), configures each of the digitizing boards upon first receiving data, reads the data from the digitizers, and formats the data for later analysis. United States Department of Energy National Labs The DOE is the nation's largest sponsor of research in

645-591: The Canadian physicist John Cunningham McLennan , who was the first to produce quantities of liquid helium almost on demand. In 1932 Einstein reported that the liquid helium could help in creating an atomic bomb. Important early work on the characteristics of liquid helium was done by the Soviet physicist Lev Landau , later extended by the American physicist Richard Feynman . In 1961, Vignos and Fairbank reported

688-498: The Continuous Electron Beam Accelerator Facility delivered the first batch of 12 GeV electrons (12.065 Giga electron Volts) to its newest experimental hall complex, Hall D. In September 2017, the official notification from the DOE of the formal approval of the 12 GeV upgrade project completion and start of operations was issued. By spring 2018, all fours research areas were successfully receiving beam and performing experiments. On 2 May 2018

731-575: The Electron Ion Collider at Brookhaven National laboratory. Jefferson builds superconducting accelerator and helium refrigeration systems for DOE accelerators around the national laboratory complex. The laboratory's main research facility is the CEBAF accelerator, which consists of a polarized electron source and injector and a pair of superconducting RF linear accelerators that are 1400 m (7/8-mile) in length and connected to each other by two arc sections that contain steering magnets. As

774-514: The Test Lab, (where the SRF cavities used in CEBAF and other accelerators used worldwide are manufactured) was constructed. As of May 2014, the upgrade achieved a new record for beam energy, at 10.5 GeV, delivering beam to Hall D. As of December 2016, the CEBAF accelerator delivered full-energy electrons as part of commissioning activities for the ongoing 12 GeV Upgrade project. Operators of

817-620: The accelerator, the laboratory has housed and continues to house a free-electron laser (FEL) instrument. The construction of the FEL started June 11, 1996. It achieved first light on June 17, 1998. Since then, the FEL has been upgraded numerous times, increasing its power and capabilities substantially. Jefferson Lab was also involved in the construction of the Spallation Neutron Source (SNS) in Oak Ridge and its upgrade, and

860-530: The associated instruments and work with visiting scientists to mount experiments with them. This access and support is provided without charge to qualified scientific groups, with priority based on recommendations by expert review panels. All six research offices support scientific user facilities at national laboratories. Facility for atmospheric observations Facility for environmental molecular sciences Facility for integrative genomic science The system of national laboratories started with

903-527: The course of the war, the Allied nuclear effort, the Manhattan Project , created several secret sites for the purpose of bomb research and material development, including a laboratory in the mountains of New Mexico directed by Robert Oppenheimer ( Los Alamos ), and sites at Hanford, Washington and Oak Ridge, Tennessee . Hanford and Oak Ridge were administered by private companies, and Los Alamos

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946-448: The distinguishing features of Jefferson Lab is the continuous nature of the electron beam, with a bunch length of less than 1 picosecond . Another is Jefferson Lab's use of superconducting Radio Frequency (SRF) technology, which uses liquid helium to cool niobium to approximately 4 K (−452.5 °F), removing electrical resistance and allowing the most efficient transfer of energy to an electron. To achieve this, Jefferson Lab houses

989-490: The effects of the interatomic forces in helium are even weaker. Because of the very weak interatomic forces in helium, the element remains a liquid at atmospheric pressure all the way from its liquefaction point down to absolute zero . At temperatures below their liquefaction points, both helium-4 and helium-3 undergo transitions to superfluids . (See the table below.) Liquid helium can be solidified only under very low temperatures and high pressures . Liquid helium-4 and

1032-489: The electron beam makes up to five successive orbits, its energy is increased up to a maximum of 6  GeV (the original CEBAF machine worked first in 1995 at the design energy of 4 GeV before reaching "enhanced design energy" of 6 GeV in 2000; since then the facility has been upgraded into 12 GeV energy). This leads to a design that appears similar to a racetrack when compared to the classical ring-shaped accelerators found at sites such as CERN or Fermilab . Effectively, CEBAF

1075-575: The ends of the linacs. The electrons make up to five passes through the linear accelerators. When a nucleus in the target is hit by an electron from the beam, an "interaction", or "event", occurs, scattering particles into the hall. Each hall contains an array of particle detectors that track the physical properties of the particles produced by the event. The detectors generate electrical pulses that are converted into digital values by analog-to-digital converters (ADCs), time to digital converters (TDCs) and pulse counters (scalers). This digital data

1118-501: The era of 12 GeV beams at Jefferson Lab, the Hall B program has been restructured to include a new detector called CLAS12, as well as several other experiments using more specialized hardware. Multiple spectrometers and specialized equipment has been used to study, for example, parity-violating electron scattering to measure the weak charge of the proton and hypernuclear production with the electromagnetic interaction. This experimental hall

1161-399: The front edge that provide input and output for digital signals, and a connector at the back that plugs into a backplane . A group of boards is plugged into a chassis , or " crate ", that provides physical support, power, and cooling for the boards and backplane. This arrangement allows electronics capable of digitizing many hundreds of channels to be compressed into a single chassis. In

1204-786: The laboratories are listed below, along with the location, establishment date, and the organization that currently operates each. UT–Battelle (since April 2000) Brookhaven Science Associates (since 1998) Triad National Security, LLC (Since 2018) Honeywell International (since 2017) Lawrence Livermore National Security, LLC (since 2007) Battelle Savannah River Alliance (Since 2021) Battelle Memorial Institute (since 2005) The DOE Office of Science operates an extensive network of 28 national scientific user facilities. A total of over 30,000 scientific users from universities, national laboratories, and technology companies use these facilities to advance their research and development. The staff of experts at each facility who build and operate

1247-587: The massive scientific endeavors of World War II , in which several new technologies, especially the atomic bomb , proved decisive for the Allied victory. Though the United States government had begun seriously investing in scientific research for national security in World War I , it was only in this wartime period that significant resources were committed to scientific problems, under the auspices first of

1290-599: The national labs serve as an exemplar for Big Science . The national laboratory system, administered first by the Atomic Energy Commission, then the Energy Research and Development Administration , and currently the Department of Energy , is one of the largest (if not the largest) scientific research systems in the world. The DOE provides about a third of the total national funding for physics , chemistry , materials science , and other areas of

1333-477: The physical sciences and engineering, and is second to the Department of Defense in supporting computer sciences and mathematics. Most of that research is performed by the national laboratories. Although the national laboratories form an integrated system, each of them has its individual mission, capabilities, and structure. The chart shows the nature of the research done at each laboratory. All 17 of

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1376-449: The products of collisions between the electron beam or with real photons and a stationary target. This allows physicists to study the structure of the atomic nucleus , specifically the interaction of the quarks that make up protons and neutrons of the nucleus. With each revolution around the accelerator, the beam passes through each of the two LINAC accelerators, but through a different set of bending magnets in semi-circular arcs at

1419-433: The rare helium-3 are not completely miscible . Below 0.9 kelvin at their saturated vapor pressure , a mixture of the two isotopes undergoes a phase separation into a normal fluid (mostly helium-3) that floats on a denser superfluid consisting mostly of helium-4. This phase separation happens because the overall mass of liquid helium can reduce its thermodynamic enthalpy by separating. At extremely low temperatures,

1462-772: The structure of the nucleon (protons and neutrons), the production and decay of light mesons, and aspects of the interactions of nucleons in the atomic nucleus. The main tools are the scattering of electrons and the creation and use of high energy real photons. In addition, both electron and photon beams can be made highly polarized, allowing exploration of so-called spin degrees of freedom in investigations. The four experimental halls have distinct but overlapping research goals, but with instrumentation unique to each. Matching high resolution spectrometers (HRS) have been used to study deep-inelastic electron scattering. Using very well controlled polarized electron beams, parity violation in electron scattering has been studied. The CLAS detector

1505-426: The superfluid phase, rich in helium-4, can contain up to 6% helium-3 in solution. This makes the small-scale use of the dilution refrigerator possible, which is capable of reaching temperatures of a few millikelvins . Superfluid helium-4 has substantially different properties from ordinary liquid helium. In 1908, Kamerlingh-Onnes succeeded in liquifying a small quantity of helium. In 1923, he provided advice to

1548-687: The wartime laboratories, extending their lives indefinitely (they were originally thought of as temporary creations). Funding and infrastructure were secured to sponsor other "national laboratories" for both classified and basic research, especially in physics , with each national laboratory centered around one or many expensive machines (such as particle accelerators or nuclear reactors ). Most national laboratories maintained staffs of local researchers as well as allowing for visiting researchers to use their equipment, though priority to local or visiting researchers often varied from lab to lab. With their centralization of resources (both monetary and intellectual),

1591-468: The world's largest liquid helium refrigerator, and it was one of the first large-scale implementations of SRF technology. The accelerator is built 8 meters below the Earth's surface, or approximately 25 feet, and the walls of the accelerator tunnels are 2 feet thick. The beam ends in four experimental halls, labelled Hall A, Hall B , Hall C, and Hall D. Each hall contains specialized spectrometers to record

1634-463: Was administered by a public university (the University of California ). Additional success was had at the University of Chicago in reactor research, leading to the creation of Argonne National Laboratory outside Chicago, and at other academic institutions spread across the country. After the war and its scientific successes, the newly created Atomic Energy Commission took over the future of

1677-494: Was built for the beginning of the 12 GeV beam-energy program starting in 2014. This hall houses the GlueX experiment, which is designed to map out the light unflavored meson spectrum in detail in the search for explicit gluonic excitations in mesons. JLab houses the world's most powerful tunable free electron laser , with an output of over 14 kilowatts . Since CEBAF has three complementary experiments running simultaneously, it

1720-484: Was decided that the three data acquisition systems should be as similar as possible, so that physicists moving from one experiment to another would find a familiar environment. To that end, a group of specialist physicists was hired to form a data acquisition development group to develop a common system for all three halls. CODA , the CEBAF Online Data Acquisition system , was the result. CODA

1763-504: Was delivered to the experimental area on 1 July 1994. The design energy of 4 GeV for the beam was achieved during the year 1995. The laboratory dedication took place on May 24, 1996 (at this event the name was also changed). Full initial operations with all three initial experiment areas online at the design energy was achieved on June 19, 1998. On August 6, 2000, the CEBAF reached "enhanced design energy" of 6 GeV. In 2001, plans for an energy upgrade to 12 GeV electron beam and plans to construct

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1806-878: Was first liquefied on July 10, 1908, by the Dutch physicist Heike Kamerlingh Onnes at the University of Leiden in the Netherlands . At that time, helium-3 was unknown because the mass spectrometer had not yet been invented. In more recent decades, liquid helium has been used as a cryogenic refrigerant (which is used in cryocoolers ), and liquid helium is produced commercially for use in superconducting magnets such as those used in magnetic resonance imaging (MRI), nuclear magnetic resonance (NMR), magnetoencephalography (MEG), and experiments in physics , such as low temperature Mössbauer spectroscopy . The Large Hadron Collider contains superconducting magnets that are cooled with 120 tonnes of liquid helium. A helium-3 atom

1849-438: Was the mainstay of the Hall B experimental program from 1998 to 2012. Physics Working Groups in the areas of Deep-Inelastic Interactions, Hadron Spectroscopy, and Nuclear Interactions exist. See the article related to the spectrometer itself and physics program at the link CLAS . Polarized real photons and electron beams were used. Physics targets included liquid hydrogen and deuterium, as well as massive nuclear materials. In

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