Holder DJ

Quinn P

Wyles N

English

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D.J. Holder , P.D. Quinn, N.G. Wyles, STFC Daresbury Laboratory, Warrington, Cheshire, UKAlsed and longer-wavelength light that DIAMOND cannot. g and diverse community of SR users buose primary source of raors and £300k for the initial bes of the first two beamlines were under de0 the SRS was form  of State for Science. Param e 1. Table 1: SRS 1.0 parameTHE SRS AT DARESBURY LABORATORY: A EULOGY TO THE WORLD'S FIRST DEDICATED HIGH-ENERGY SYNCHROTRON RADIATION SOURCE #bstract2008 marks the last year of operation of the Synchrotron Radiation Source (SRS) at Daresbury Laboratory, which circulated its first 2 GeV beam in 1981. This paper provides a look back at the significant milestones passed on the way and records the achievements of many of those involved in its thirty-year programme. Many of the technologies and techniques developed at the SRS at Daresbury are now standard practice at synchrotron light sources around the world; and there are few light source laboratories that do not benefit from the skills of someone who spent their formative years working on the SRS. The provision of synchrotron light for the UK is now being met by DIAMOND, whose success is a testament to the skills of its designers, honed as they were on the SRS at Daresbury. These skills are now being used to design the UK’s next-generation light source, to provide the puIN THE BEGINNING Synchrotron Radiation (SR) research started at Daresbury Laboratory in 1968. A facility to exploit the radiation from the high-energy physics accelerator NINA, a pulsed 6GeV electron synchrotron, was approved in 1969 and ran until the closure of NINA on 1st April 1977. In this period a stronilt up in the UK.  The first international symposium for SR users took place at Daresbury Laboratory in 1973 and provided early impetus for the development of the world’s first dedicated x-ray synchrotron radiation source. This was to be a second-generation source whdiation is the lattice dipoles. Work on the science case and costs then started in earnest, leading to approval for the SRS at Daresbury in October 1974. The 4-year project started in April 1975 with £3M for the acceleratam ports and beamlines.  By the end of 1979 the construction and commissioning of the 600 MeV injector, consisting of a linac and a booster synchrotron, were complete. The construction of the 2 GeV electron storage ring was well advanced and schematic diagramvelopment.  A major milestone, circulating the first beam in the storage ring was achieved on 30th June 1980 (see Fig. 1), initiating an intense period of accelerator physics study. Construction of the first two beamlines on ports 6 and 7 was now top priority and on the 7th November 198ally opened by the Ministereters of SRS 1 are shown in Tableters Parameter Valu UnitsLinac energy 12 MeV Booster (injection) energy 060 MeVStored beam energy 2 GeVStorage ring circumference 96 mLattice type FODONumber of cells (2 dipoles/cell) 8Dipole bend radius 5.6 mDipole field 1.2 TRF frequency 500 MHzRevolution freq  MHz uency 3.123FIRST OPERATION The first scheduled operation of the SRS for users started in the spring of 1981. There were facilities for Extended X-ray Absorption Fine Structure (EXAFS), protein crystallography and x-ray topography on line 7 and for surface electron diffraction and surface EXAFS on line 6. Development of beamlines for UV/visible timing experiments and infra-red spectroscopy approached completion.  Figure 1: The first beam in the SRS storage ring. ___________________________________________  #d.j.holder@dl.ac.uk Proceedings of EPAC08, Genoa, Italy WEPC06202 Synchrotron Light Sources and FELs A05 Synchrotron Radiation Facilities2133The electron beam operating current and energy were built up over several months and achieved full design specification at 2 GeV in March 1982. Normal high current operations of the SRS used all 160 RF buckets with a multibunch lattice tuning was christened HiQ. HBL parameters of the SRS are shown Table 2. Improvements to the Photon Beam Quality Following re-commissioning of the storage ring and the beamlines, user operations on the SRS resumtotal circulating current typically around 300mA. Additional work to allow operation at low current with all charge in a single ial class of time-pleted in March storage ring modification was the perconducting wiggler magnet of x-rays available to higher enion to the user  the year due to repeated A recovery programme wand 1986 was characterised s for users for over 5000 hotensity to very high brightness, ren single bunch  was ormal ed in Seducting wiggler magnet at 6 tesla. T1994 with the replacemm ystems and wide- ntroduction o  p n monitors around the facility. l b n in bo  planes was estab ; i sed photon beam p ion d VD-based algorithn meterse its bunch for a specresolved SR experiments was also com1982.  UPGRADES Superconducting Wiggler The first major installation of a 5 tesla suto extend the spectrum ergies. This device was brought into operation for users in November 1982. Full-Time Operation In 1983 the SRS switched from 16 hour per day to 24 hour operations but suffered severe disruptprogramme towards the end offailures of RF cavity windows. as launched which ultimately led to some RF system design changes which solved the problem. First Undulator Installed The period between 1984 by high-reliability operationurs per year. The first undulator device was installed in October 1984 (see Fig 2). High Brightness Lattice SR research internationally was growing rapidly and the emphasis in the output properties of the sources was changing from very high inquiring a reduction in the dimensions of the electron beam source. The design of a major modification to the SRS to achieve higher brightness was planned and completed in this period.  The SRS was shutdown in October 1986 for the upgrade to the so-called “High Brightness Lattice” (HBL). The eight original twin-dipole cells were split by the addition of a further sixteen quadrupoles to produce a sixteen cell lattice. Further sextupoles and steering magnets were also added to the storage ring. This major engineering reconstruction of the storage ring required the reconstruction of every straight section by staff working two shifts a day to complete the construction programme on schedule by March 1987. After this upgrade the normal multibunch circulating current was 220mA, while in single bunch operation it was around one-tenth of this. In order to achieve a reasonable lifetime ioperation, a special lattice tuning, known as LoQused to increase the vertical beam size. The nptember 1987. Attention then shifted to projects which would improve the quality of the photon beam for users. These included a modernisation of all beamline photon position monitoring systems and an upgrade of the systems to monitor and control electron beam position. Approval was also given for a design study to consider a second superconThe 6 tesla wiggler project was funded in 1990, installed during the November 1991 - June 1992 shutdown and available for use by users in July 1993. There was good progress on SRS beam stability systems with the establishment of a photon beam monitor test facility and the replacement of the steering magnet control system. he conclusion of the beam quality projects came inent of electron beam position onitoring s scale i f newhoton beam positioeam position stabilisatioGlobalishedthn the vertical plane this u the ositata and an S m.  Table 2: SRS “High Bright ess Lattice” paraParameter Valu UnStored beam energy V2 GeStorage ring circumference 96 mLattice type FODONumber of cells (1 dipole/cell) 16Dipole bend radius 5.6 mDipole field 1.2 TRF frequency 500 MHzBunch spacing 2 nsBunch length (typical) 050-10 psHiQ LoQHorizontal tune 6.19 4.21  Vertical tune 3.37 3.21  Momentum compaction 0.029 0.058  Emittance (2 GeV) 104 258 nmrad Gapped Beam Over the next three years, the SRS operated with very throughout a heavy schedule of over 6500 total operating time with 5500 hours for ushigh reliability hours per year ers. Beam lifetime was enhanced by the introduction of WEPC062 Proceedings of EPAC08, Genoa, Italy02 Synchrotron Light Sources and FELs2134A05 Synchrotron Radiation Facilitiesa gap in the stored beam filling structure to stop ion trapping. Pioneering work was carried out operating the current (“microamp beam”) for etectors. ry and constructed by Sincrotone Trieste. One consequence of this upgrade all four RF ache storage ring klystron and to replace t for the two superconducting neering enhancements have inring. A ne  Apple-II type variable polarisation undulator (see Fig. 3) was installed in 2004, which required the removal of the existing undulator. The successful design, magnet lock sorting and shimming of this device pushed the oundaries of Daresbury’s insertion device capability further. This device was the first SRS accelerator component for which control was handed over to the user, allowing them to select not only the wavelength, but also polarisation (linear, L or R circular or elliptical).  SRS at extremely low calibration of astronomical dNobel Prize In 1997 a share of the Nobel Prize for chemistry was awarded to Dr. John Walker for determining the structure of F1-ATPase. Data collected at the SRS formed a vital part of this research, and this is believed to be the only Nobel Prize to include work on a SR source. Multipole Wigglers A second major rebuilding of the storage ring was undertaken in 1998 to install two 2 tesla hybrid permanent magnet multipole wigglers designed at Daresbuwas the need to relocate Figure 2: The first insertion device installed in the SRS in 984, the U5 undulator. celerating cavities. The SRS shutdown in October 1998 for the three-month upgrade installation with staff working seven days a week to achieve a challenging programme to minimise the loss of experimental time. First turns after this work were achieved during the afternoon of the laboratory’s Christmas party, and user operations resumed on schedule in January 1999. THE FINAL YEARS In 2000, after 20 years of storage ring operation, it was necessary to review the investment needed to maintain the SRS’s reliability in the face of obsolescence in some systems. Projects were launched initially to replace the power supply for t1the liquid helium cryoplanwigglers. Smaller engicluded replacement of many pulsed powers supplies, replacement of the electron BPM monitoring electronics, replacement of parts of the accelerator timing systems and venting of the booster synchrotron to replace all vacuum seals and orbit correction windings. These improvements will ensure the reliable operation of the SRS through to the end of its life. APPLE-II Undulator However, there was also funding for three further major enhancements; a new protein crystallography facility requiring a 2.4 tesla hybrid permanent magnet multipole wiggler and an advanced infra-red beamline. The installation of this insertion device filled the final remaining straight section space in the storage Figure 3: The last in o be installed in the SR08. Prior to this, a programme of phased decommissioning of experimental stations and beamlines is underway. Thi y complete dis-ashat the future will be very different. However, everybody involved with the SRS can look back with pride at what was achieved, and the esprit de corps generated will serve the laboratory well in its future endeavours.  sertion device tS, in 2004, shown on test; it is an Apple-II-style undulator, which replaced U5. THE END User operation of the SRS is scheduled to end in August 20s will be followed bsembly and disposal of the accelerator in the subsequent year.CONCLUSION The closure of the SRS is the end of an era at Daresbury Laboratory and it is clear twbbProceedings of EPAC08, Genoa, Italy WEPC06202 Synchrotron Light Sources and FELs A05 Synchrotron Radiation Facilities2135

The SRS at Daresbury Laboratory: a Eulogy to the World's First Dedicated High-energy Synchrotron Radiation Source

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