The European Spallation Source ERIC (ESS) is a multi-disciplinary research facility based on the world's most powerful pulsed neutron source. It is currently under construction in Lund, Sweden. The ESS Data Management and Software Centre (DMSC) will be located in

Copenhagen, Denmark Copenhagen ( or .; da, København ) is the capital and most populous city of Denmark, with a proper population of around 815.000 in the last quarter of 2022; and some 1.370,000 in the urban area; and the wider Copenhagen metropolitan ...

. The 13 European member countries act as partners in the construction and operation of ESS. ESS will start the scientific user programme in 2023, and the construction phase will be complete by 2025. ESS is the world's most powerful next-generation neutron source, and will enable scientists to see and understand basic atomic structures and forces at length and time scales unachievable at other neutron sources. The research infrastructure, owned by 13 European nations, is built close to the Max IV Laboratory. The colocation of powerful neutron and x-ray facilities is a productive strategy (e.g. the

Institut Laue–Langevin The Institut Laue–Langevin (ILL) is an internationally financed scientific facility, situated on the Polygone Scientifique in Grenoble, France. It is one of the world centres for research using neutrons. Founded in 1967 and honouring the phy ...

with the

European Synchrotron Radiation Facility The European Synchrotron Radiation Facility (ESRF) is a joint research facility situated in Grenoble, France, supported by 22 countries (13 member countries: France, Germany, Italy, the UK, Spain, Switzerland, Belgium, the Netherlands, Denmark, ...

; the

ISIS Neutron and Muon Source The ISIS Neutron and Muon Source is a pulsed neutron and muon source, established 1984 at the Rutherford Appleton Laboratory of the Science and Technology Facilities Council, on the Harwell Science and Innovation Campus in Oxfordshire, Unite ...

with the

Diamond Light Source Diamond Light Source (or Diamond) is the UK's national synchrotron light source science facility located at the Harwell Science and Innovation Campus in Oxfordshire. Its purpose is to produce intense beams of light whose special characteristi ...

), because much of the knowledge, technical infrastructure, and scientific methods associated with neutron and x-ray technologies are similar. The construction of the facility began in the summer of 2014 and the first science results produced are planned for 2023. Scientists and engineers from more than 100 partner laboratories are working on updating and optimising the advanced technical design of the ESS facility, and at the same time are exploring how to maximise its research potential. These partner laboratories, universities and research institutes are also contributing human resources, knowledge, equipment, and financial support through In-Kind Contributions. ESS will use nuclear

spallation Spallation is a process in which fragments of material ( spall) are ejected from a body due to impact or stress. In the context of impact mechanics it describes ejection of material from a target during impact by a projectile. In planetary p ...

, a process in which

neutron The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons behav ...

s are liberated from heavy elements by high energy protons. This is intrinsically a much safer process than uranium

fission Fission, a splitting of something into two or more parts, may refer to: * Fission (biology), the division of a single entity into two or more parts and the regeneration of those parts into separate entities resembling the original * Nuclear fissio ...

. Unlike existing facilities, the ESS is neither a "short pulse" (micro-seconds) spallation source, nor a continuous source like the SINQ facility in Switzerland, but the first example of a "long pulse" source (milli-seconds) . The future facility is composed of a linear accelerator in which protons are accelerated and collide with a rotating, helium-cooled

tungsten Tungsten, or wolfram, is a chemical element with the symbol W and atomic number 74. Tungsten is a rare metal found naturally on Earth almost exclusively as compounds with other elements. It was identified as a new element in 1781 and first isol ...

target. By this process, intense pulses of

s are generated. Surrounding the tungsten are baths of cryogenic hydrogen which feed supermirror guides. These operate in a similar way to optical fibres, directing the intense beams of neutrons to experimental stations, where research is done on different materials. Many of the instruments benefit from more than a decade of development, and several of the designs are unique in order to maximise the benefits of the long pulse. Neutron scattering can be applied to a range of scientific questions, spanning the realms of physics, chemistry, geology, biology and medicine. Neutrons serve as a unique probe for revealing the structure and function of matter from the microscopic down to the atomic scale. Using neutrons for research enables us to investigate the world around us as well as to develop new materials and processes to meet the needs of society. Neutrons are frequently used to address the grand challenges, to improve and develop new solutions for health, the environment, clean energy, IT and more. ESS became a European Research Infrastructure Consortium, or ERIC, on 1 October 2015. The European Spallation Source ERIC is "a joint European organisation committed to constructing and operating the world's leading facility for research using neutrons." ESS is designed to be carbon-neutral and is expected to reduce CO₂ emissions in the region. Though it is just over half way through the construction project, the ESS is already a scientifically productive organisation. Many world-leading experts are either directly employed or linked to the project via collaborations, and working on pressing societal problems. Examples include the determination of protein structure in COVID-19 and the provision o
deuteration services
to other scientists. The European Investment Bank made a €50 million investment in European Spallation Source. This investment is supported by InnovFin-EU Finance for Innovators, an initiative established by the EIB Group in collaboration with the

European Commission The European Commission (EC) is the executive of the European Union (EU). It operates as a cabinet government, with 27 members of the Commission (informally known as "Commissioners") headed by a President. It includes an administrative body ...

under

Horizon 2020 The Framework Programmes for Research and Technological Development, also called Framework Programmes or abbreviated FP1 to FP9, are funding programmes created by the European Union/European Commission to support and foster research in the Europea ...

, the EU's research and innovation program.

History

Building of European Spallation Source, January 2017

When the ISIS neutron source was built in England in 1985, its radical success in producing indirect images of molecular structures eventually raised the possibility of a far more powerful spallation source. By 1993, the European Neutron Scattering Association began to advocate what would be the most ambitious and broad-based spallation source in the world, ESS. Neutron science soon became a critical tool in the development of industrial and consumer products worldwide. So much so that the Organization for Economic Development (OECD), declared in 1999 that a new generation of high-intensity neutron sources should be built, one each in North America, Asia and Europe. Europe's challenge was its diverse collection of national governments, and an active research community numbering in the thousands. In 2001, a European roadmap for developing

accelerator driven systems A subcritical reactor is a nuclear fission reactor concept that produces fission without achieving criticality. Instead of sustaining a chain reaction, a subcritical reactor uses additional neutrons from an outside source. There are two general c ...

for nuclear waste incineration estimated that the ESS could have the beam ready for users in 2010. A European international task force gathered in Bonn in 2002 to review the findings and a positive consensus emerged to build ESS. The stakeholders group met a year later to review the task force's progress, and in 2003 a new design concept was adopted that set the course for beginning operations by 2019. Over the next five years a competitive and yet collaborative site selection process played out and Lund, Sweden was chosen as the preferred site; the definitive selection of Lund was announced in Brussels on 28 May 2009. On 1 July 2010, the staff and operations of ESS Scandinavia were transferred from

Lund University , motto = Ad utrumque , mottoeng = Prepared for both , established = , type = Public research university , budget = SEK 9 billion As of 2013 the estimated cost of the facility will be about €1.843 bn. Host nations Sweden and Denmark plan to give about half of the sum. However the negotiations about the exact contributions from every partner are still in progress. From 2010 to 30 September 2015, ESS was operated as a Swedish ''aktiebolag'', or AB.

Site selection

Originally, three possible ESS sites were under consideration:

Bilbao ) , motto = , image_map = , mapsize = 275 px , map_caption = Interactive map outlining Bilbao , pushpin_map = Spain Basque Country#Spain#Europe , pushpin_map_caption ...

(Spain),

Debrecen Debrecen ( , is Hungary's second-largest city, after Budapest, the regional centre of the Northern Great Plain region and the seat of Hajdú-Bihar County. A city with county rights, it was the largest Hungarian city in the 18th century and i ...

(Hungary) and Lund (Sweden). On 28 May 2009, seven countries indicated support for placing ESS in Sweden. Furthermore, Switzerland and

Italy Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical ...

indicated that they would support the site in majority. On 6 June 2009, Spain withdrew the Bilbao candidacy and signed a collaboration agreement with Sweden, supporting Lund as the main site, but with key component development work being performed in Bilbao. This effectively settled the location of the ESS; detailed economical negotiations between the participating countries are now taking place. On 18 December 2009, Hungary also chose to tentatively support ESS in Lund, thus withdrawing the candidacy of Debrecen. The construction of the facility began in early 2014, with a groundbreaking event held in September of that year. The user programme will start in 2023, and it is planned to be fully operational by 2025. ESS provide
weekly updates of construction progress
an
live construction site webcams
on its website.

The Linear Accelerator

The ESS uses a linear accelerator (

linac A linear particle accelerator (often shortened to linac) is a type of particle accelerator that accelerates charged subatomic particles or ions to a high speed by subjecting them to a series of oscillating electric potentials along a linear ...

) to accelerate a beam of protons from the exit of its ion source at 75 keV to 2

GeV GEV may refer to: * ''G.E.V.'' (board game), a tabletop game by Steve Jackson Games * Ashe County Airport, in North Carolina, United States * Gällivare Lapland Airport, in Sweden * Generalized extreme value distribution * Gev Sella, Israeli-South ...

, at the entrance of the accelerator protons are traveling at ~1% of the

speed of light The speed of light in vacuum, commonly denoted , is a universal physical constant that is important in many areas of physics. The speed of light is exactly equal to ). According to the special theory of relativity, is the upper limit fo ...

and at the end of the accelerator, they reach a velocity of ~95% speed of light. The accelerator uses both normal conducting and superconducting cavities. The normal conducting cavities are Radio Frequency Quadrupole,

RFQ A Request for Quote (RfQ) is a financial term for certain way to ask a bank for an offer of a given financial instrument from a bank, made available by so-called Approved Publication Arrangement (APA) by the stock markets itself or by Financial d ...

, working at a frequency of 352.21 MHz, and accelerating the proton beam up to an energy of 3.62 MeV. The next structure is a transport line for the medium energy protons, MEBT which transports the beam from the RFQ to the next structure for further acceleration. In the MEBT the beam properties are measured, the beam is cleaned from the transverse halo around the beam, and also the head and tail of the beam pulse are cleaned using a transversally deflecting electromagnetic chopper. The Drift Tube Linac, DTL, which is the structure downstream of the MEBT accelerates the beam further to ~90 MeV. At this energy, there is a transition from normal conducting cavities to superconducting cavities. Three families of superconducting cavities accelerate the beam to its final energy of 2 GeV, firstly a section using double-spoke cavities up to an energy of ~216 Mev, then two families of elliptical cavities which are optimized for medium and high energy proton acceleration at a frequency of 704.42 MHz. Following the elliptical cavities, a transfer-line guides the beam to the target, and just before sending the beam to the target for producing spallation neutrons expands the beam and paints the target to dissipate the generated heat over a larger area. The linac repetition rate is 14 Hz, and the pulses of protons are 2.86 ms long, making the duty factor of the linac 4%. The beam current within the pulse is 62.5 mA, and the average beam current is 2.5 mA. Except in the RFQ which uses the same structure and field to accelerate and focus the beam, the transverse focusing of the beam of protons is performed using magnetic lenses. In the low energy beam transport, right after the ion source, magnetic

solenoid upright=1.20, An illustration of a solenoid upright=1.20, Magnetic field created by a seven-loop solenoid (cross-sectional view) described using field lines A solenoid () is a type of electromagnet formed by a helix, helical coil of wire whose ...

s are used, in the DTL permanent

quadrupole A quadrupole or quadrapole is one of a sequence of configurations of things like electric charge or current, or gravitational mass that can exist in ideal form, but it is usually just part of a multipole expansion of a more complex structure ref ...

magnet A magnet is a material or object that produces a magnetic field. This magnetic field is invisible but is responsible for the most notable property of a magnet: a force that pulls on other ferromagnetic materials, such as iron, steel, nic ...

s are used and the rest of the linac uses electromagnetic quadrupoles.

The spallation target and its environmental impact

*The ESS source will be built around a solid

target, cooled by

helium Helium (from el, ἥλιος, helios, lit=sun) is a chemical element with the symbol He and atomic number 2. It is a colorless, odorless, tasteless, non-toxic, inert, monatomic gas and the first in the noble gas group in the periodic table. ...

gas. * Radioactive substances will be generated by the

process, but the solid target makes the handling of these materials easier and safer than if a liquid target had been used. * ESS, ''E.on'', and ''Lunds Energi'' are collaborating in a project aiming to get the facility to be the world's first completely sustainable large-scale research centre through investment in

wind power Wind power or wind energy is mostly the use of wind turbines to generate electricity. Wind power is a popular, sustainable, renewable energy source that has a much smaller impact on the environment than burning fossil fuels. Historicall ...

. The ESS project is expected to include an extension of the Nysted Wind Farm. *

Radioactive material A radionuclide (radioactive nuclide, radioisotope or radioactive isotope) is a nuclide that has excess nuclear energy, making it unstable. This excess energy can be used in one of three ways: emitted from the nucleus as gamma radiation; transfer ...

storage and transport will be required, but the need is much less than that of a

nuclear reactor A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. Heat from nu ...

. *ESS expects to be CO₂-neutral. *Recent design improvements will decrease energy usage at ESS.

Neutron Scattering and Imaging Instruments at ESS

The target station is surrounded by instrument halls with scientific instruments placed in four sections in the cardinal directions. In the western section, science instruments are located 156 meters from the center of the target station. In the southern one, the distance is between 50 and 80 meters, and the science instruments located closest to the target station are in the northern and eastern sections. Initially, 15 different scientific instruments will be erected: Large-scale structures: * ODIN (Imaging) * SKADI (General purpose SANS) * LoKI (Broadband SANS) * FREIA (Horizontal reflectometer) * ESTIA (Vertical reflectometer) Diffraction: * HEIMDAL (Powder

diffractometer A diffractometer is a measuring instrument for analyzing the structure of a material from the scattering pattern produced when a beam of radiation or particles (such as X-rays or neutrons) interacts with it. Principle Because it is relatively eas ...

) * DREAM (Powder diffractometer) * BEER (Engineering diffractometer) * MAGiC (Magnetism diffractometer) * NMX (Macromolecular diffractometer)

Spectroscopy Spectroscopy is the field of study that measures and interprets the electromagnetic spectra that result from the interaction between electromagnetic radiation and matter as a function of the wavelength or frequency of the radiation. Matter ...

: * CSPEC (Cold chopper

spectrometer A spectrometer () is a scientific instrument used to separate and measure spectral components of a physical phenomenon. Spectrometer is a broad term often used to describe instruments that measure a continuous variable of a phenomenon where th ...

) * T-REX (Thermal chopper spectrometer) * BIFROST (Crystal analyser spectrometer) * VESPA (Vibrational spectrometer) * MIRACLES (Backscattering spectrometer)

ESSnuSB

The ESS neutrino super beam project aims to generate the most powerful neutrino beam in the world.

References

External links

European Spallation Source website
The most up-to-date source for information on the ESS project.
Weekly updates of the construction of ESS and live webcams at the construction site.
*
essworkshop.org
- See how the design of instrumentation for a future ESS-Scandinavia is moving forward.
BrightnESS, EU grant project in support of ESS.SREss, EU grant project in support of ESS.
{{Coord, 55.7350, N, 13.2514, E, source:wikidata, display=title Lund Lund University Neutron scattering Nuclear physics Neutron facilities Particle physics facilities 2019 in Sweden