Канаданың ұлттық синхротрон жарық көзі: Саскатун кеністігі

Synchrotron light source facility in Saskatoon, Canada

The Canadian Light Source (CLS) is Canada's national synchrotron light source facility, located on the grounds of the University of Saskatchewan in Saskatoon, Saskatchewan, Canada. The CLS has a third generation 2.9 GeV storage ring, and the building occupies a footprint the size of a Canadian football field. It opened in 2004 after a 30 year campaign by the Canadian scientific community to establish a synchrotron radiation facility in Canada. with over 1000 individual users, it hosts scientists from all regions of Canada and around 20 other countries. Research at the CLS has ranged from viruses
and its high school education programs.

Canadian interest in synchrotron radiation dates from 1972, when Bill McGowan of the University of Western Ontario (UWO) organised a workshop on its uses. At that time there were no users of synchrotron radiation in Canada. In 1973 McGowan submitted an unsuccessful proposal to the National Research Council (NRC) for a feasibility study on a possible synchrotron lightsource in Canada. In 1975 a proposal to build a dedicated synchrotron lightsource in Canada was submitted to NRC. This was also unsuccessful. In 1977 Mike Bancroft, also of UWO, submitted a proposal to NRC to build a Canadian beamline, as the Canadian Synchrotron Radiation Facility (CSRF), at the existing Synchrotron Radiation Center at the University of Wisconsin Madison, USA, and in 1978 newly created NSERC awarded capital funding. CSRF, owned and operated by NRC, grew from the initial beamline to a total of three by 1998. A further push towards a Canadian synchrotron light source started in 1990 with formation of the Canadian Institute for Synchrotron Radiation (CISR), initiated by Bruce Bigham of Atomic Energy of Canada Limited (AECL). AECL and TRIUMF showed interest in designing the ring, but the Saskatchewan Accelerator Laboratory (SAL) at the University of Saskatchewan became prominent in the design. In 1991 CISR submitted a proposal to NSERC for a final design study. This was turned down, but in later years, under President Peter Morand, NSERC became more supportive. In 1994 NSERC committee recommended a Canadian synchrotron light source and a further NSERC committee was formed to select between two bids to host such a facility, from the Universities of Saskatchewan and Western Ontario. In 1996 this committee recommended that the Canadian Light Source be built in Saskatchewan. With NSERC unable to supply the required funds it was not clear where funding would come from. In 1997 the Canada Foundation for Innovation (CFI) was created to fund large scientific projects, possibly to provide a mechanism to fund the CLS. In 1998 a University of Saskatchewan team led by Dennis Skopik, the SAL director, submitted a proposal to CFI. The proposal was to fund 40% of the construction costs, with remaining money having to come from elsewhere. Assembling these required matching funds has been called "an unprecedented level of collaboration among governments, universities, and industry in Canada" and Bancroft – leader of the rival UWO bid – anckowledged the "Herculean" efforts of the Saskatchewan team in obtaining funds from the University, the City of Saskatoon, Saskatchewan Power, NRC, the Provincial Government of Saskatchewan, and Western Economic Diversification. The new building – attached to the existing SAL building, and measuring 84m by 83m in area with a maximum height of 23m – was completed in early 2001. The SAL LINAC was refurbished and placed back into service in 2002 while the booster and storage rings were still under construction. New director Bill Thomlinson, an expert in synchrotron medical imaging, arrived in November 2002. He was recruited from the European Synchrotron Radiation Facility where he had been the head of the medical research group. The 1991 proposal to NSERC envisioned a 1.5 GeV storage ring, since at this time the interest of the user community was mainly in the soft X ray range. The ring was a racetrack layout of four to six bend regions surrounding straights with extra quadrupoles to allow for variable functions in the straights. The design contemplated the use of superconducting bends in some locations to boost
the photon energies produced. The drawback of this design was the limited number of straight sections. In 1994 a more conventional machine with 8 straight sections was proposed, again with 1.5 GeV energy. At this time more users of hard X rays were interested and it was felt that both the energy and number of straight sections were too low. By the time funding was secured in 1999 the design had changed to 2.9 GeV, with longer straight sections to enable two insertion devices per straight, delivering beam to two independent beamlines. Construction of the storage ring was completed in August 2003 and commissioning began the following month. Although beam could be stored, in March 2004 a large obstruction was found across the center of the chamber. Commissioning proceeded quickly after this was removed, and by June 2004 currents of 100mA could be achieved
On 22 October 2004 the CLS officially opened, with an opening ceremony attended by federal and provincial dignitaries, including then Federal Minister of Finance Ralph Goodale and then Saskatchewan Premier Lorne Calvert, university presidents and leading scientists. October 2004 was declared "Synchrotron Month" by the city of Saskatoon and the Saskatchewan government. Peter Mansbridge broadcast the CBC's nightly newscast The National from the top of the storage ring the day before the official opening. In parliament local MP Lynne Yelich said "There were many challenges to overcome, but thanks to the vision, dedication and persistence of its supporters, the Canadian Light Source synchrotron is open for business in Saskatoon."

The initial funding included seven beamlines, referred to as Phase I, which covered the full spectral range: two infrared beamlines, three soft X ray beamlines and two hard X ray beamlines. The first external user was hosted in 2005, and the first research papers with results from the CLS were published in March 2006 – one from the University of Saskatchewan on peptides and the other from the University of Western Ontario on materials for organic light emitting diodes. A committee was set up in 2006 to peer review proposals for beamtime, under the chairmanship of Adam Hitchcock of McMaster University. By 2007 more than 150 external users had used the CLS, and all seven of the initial beamlines had achieved significant results. and construction on the expansion needed to house the phase III Brockhouse beamline started in July 2011 and is still ongoing as of July 2012. Bill Thomlinson retired in 2008, and in May of that year physics professor Josef Hormes of the University of Bonn, former director of the CAMD synchrotron at Louisiana State University was announced as the new director. Science fiction author Robert J. Sawyer was writer in residence for two months in 2009 in what he called a "once in a lifetime opportunity to hang out with working scientists" While there he wrote most of the novel "Wonder", which won the 2012 Prix Aurora Award for best novel." By the end of 2010 more than 1000 individual researchers had used the facility, and the number of publications had passed 500.

An international team led by University of Calgary professor Ken Ng solved the detailed structure of RNA polymerase using X ray crystallography at the CLS. This enzyme replicates itself as the Norwalk virus spreads through the body, and has been linked to other superviruses such as hepatitis C, West Nile virus and the common cold. Its duplication is responsible for the onset of such viruses. CLS scientist Luca Quaroni and University of Saskatchewan professor Alan Casson used infrared microscopy to identify biomarkers inside individual cells from tissue associated with Barrett's esophagus. This disease can lead to an aggressive form of cancer known as esophageal adenocarcinoma. Researchers from Lakehead University and the University of Saskatchewan used the CLS to investigate the deaths of Royal Navy sailors buried in Antigua in the late 1700s. They used X ray fluorescence to look for trace elements such as lead and strontium in bones from a recently excavated naval cemetery

Scientists from Stanford University worked with CLS scientists to design a cleaner, faster battery. The new battery charges in less than two minutes, thanks to a newly developed carbon nanostructure. The team grew nanocrystals of iron and nickel on carbon. Traditional batteries lack this structure, mixing iron and nickel with conductors more or less randomly. The result was a strong chemical bond between the materials, which the team identified and studied at the synchrotron. A team led by the Politecnico di Milano, including scientists from the University of Waterloo and the University of British Columbia, found the first experimental evidence that a charge density wave instability competes with superconductivity in high temperature superconductors. They used four synchrotrons including the REIXS beamline at CLS. Using the X ray spectromicroscopy beamline, a research team led by scientists from the State University of New York, Buffalo produced images of graphene showing how folds and ripples act as speed bumps for electrons, affecting its conductivity. This has implications for the use of graphene in a variety of future products. A collaboration between the University of Regina and the Royal Saskatchewan Museum has been investigating dinosaur fossils at the CLS, including "Scotty," a Tyrannosaurus found in Saskatchewan in 1991, one of the most complete and largest T rex skeletons ever found. They looked at the concentration of elements in bones to study the impact of the environment on such animals.

From inception, the CLS showed a "strong commitment to industrial users and private/public partnerships", with then director Bancroft reporting "more than 40 letters of support from industry indicating that [the CLS] is important for what they do". The CLS has an industrial group, within the larger experimental facilities division, with industrial liaison scientists who make synchrotron techniques available to a "non traditional" user base who are not synchrotron experts. By 2007 more than 60 projects had been carried out,

The CLS has stated that "the primary means of accessing the CLS is through a system of peer review, which ensures that the proposed science is of the highest quality and permits access to the facility to any interested researcher, regardless of regional, national, academic, industrial or governmental affiliation." He gave a speech on the mezzanine level of the building following his tour of the facility, praising the project for helping to reverse the brain drain of scientists from Canada. In August 2010 then Governor General Michaëlle Jean visited the CLS as part of a two day tour of Saskatchewan. In April 2012 the CLS was "visited" remotely by Governor General David Johnston. He was visiting the LNLS synchrotron in Brazil, during a live link up, by video chat and remote control software, between the two facilities. January 18, 2017 Canadian Science Minister Kirsty Duncan toured the complex.

With the NRU reactor at the Chalk River Laboratories due to close in 2016, there was a need to find alternative sources of the medical isotope technetium 99m, a mainstay of nuclear medicine. In 2011 the Canadian Light Source received $14 Million in funding to investigate the feasibility of using an electron LINAC to produce molybdenum 99, the parent isotope of technetium 99. As part of this project a 35MeV LINAC has been installed in an unused underground experimental hall previously used for photonuclear experiments with the SAL LINAC. First irradiations are planned for late summer 2012, with the results to be evaluated by the Winnipeg Health Sciences Centre. This project lead to the founding a spin off company — Canadian Isotope Innovations Corporation (CIIC), which was described as part of CEO Rob Lamb's 'legacy of accomplishment' when he departed the facility in 2021. The CIIC declared bankruptcy in 2024.

The CLS has an education program – "Students on the Beamlines" – funded by NSERC Promoscience. This outreach program for science allows high school students to fully experience the work of a scientist, in addition to having the chance to use the CLS beamlines. "The program allows students the development of active research, a very rare phenomena in schools and provides direct access to the use of a particle accelerator, something even rarer!" said teacher Steve Desfosses form College Saint Bernard, Drummondville, Quebec. Dene students from La Loche, Saskatchewan have taken part in this program twice, looking at effects of acid rain. Student Jontae DesRoches commented "Elders have noticed that the landscape, where trees used to grow, there's none growing anymore. They're pretty concerned because wildlife is disappearing. Like, here there used to be rabbits and now there's none". In May 2012 three student groups were at the CLS simultaneously, with the La Loche students as the first to use the IDEAS beamline. Students from six provinces as well as the Northwest Territories have been directly involved in experiments, some of which have yielded publishable quality research. The LINAC was operated for over 30 years as part of the Saskatchewan Accelerator Lab and operates at 2856 MHz. The 78m low energy transfer line takes the electrons from the below ground LINAC to the ground level booster in the newer CLS building, via two vertical chicanes. The full energy 2.9 GeV booster, chosen to give high orbit stability in the storage ring, operates at 1 Hz, with an RF frequency of 500 MHz, unsynchronised with the LINAC. This results in significant beam loss at the extraction energy. The CLS is the smallest of the newer synchrotron facilities, which results in a relatively high horizontal beam emittance of 18.2 nm rad. Phase III will add four more devices, filling 8 of the 9 available straight sections. Longer term development includes the replacement of two of the phase I undulators with elliptically polarizing devices. Since 2021, the ring operates in a top up mode during normal user operations, injecting every few minutes to maintain a stable ring current just below 220 mA. Prior to this change, the ring operated with a fill current of 250mA in decay mode, with two injections per day.