The impact of synchrotron radiation in protein crystallography

The Pohang Light Source (PLS) at the Pohang Accelerator Laboratory (PAL) is a third-generation light source, the only synchrotron radiation facility in Korea, and the fifth machine of its kind in the world (see Figure 1). In 1988, PAL was organized for the construction of the PLS. Ground-breaking was celebrated in 1991, and PLS construction was completed in 1994. In 1995, the PLS opened two beamlines to public users. The PLS was initially operated at 2.0 GeV in 1995. Since 2002, the energy of the electron beam has been upgraded to 2.5 GeV (see Table 1 for the principal parameters of PLS). Remarkable increases in the number of beamlines, users, and scientific results have been achieved since the opening of the PLS in 1995. Two or three beamlines have been added each year for the past 15 years, and as of February 2009 we have in total 27 beamlines in operation and 3 beamlines under construction, which will be completed by the end of 2009 (Figures 2 and 3).     

New products

The UVSOR facility is a low-energy synchrotron radiation facility belonging to the Institute for Molecular Science in Okazaki, Japan. Since the first light in 1983, this facility has been operational as a national synchrotron light source for lower-energy photons from the terahertz wave to soft X-rays. The machine is operated for more than 2500 hours in a year. The cumulative number of users in a year is around 1,000. The UVSOR accelerator complex consists of a 15 MeV injector linac, a 750 MeV booster synchrotron, and a 750 MeV storage ring. The circumference of the ring is 53 m. A recent view of the storage ring and beamlines is shown in Figure 1.     

Adventures with Synchrotron Radiation at Harvard

In the late 1950s, a 6 GeV electron synchrotron (the CEA) was being built at Harvard/MIT. Ed Purcell, who generally trafficked in volts (or maybe kilovolts), but never gigavolts, was thinking about what one could do with all that synchrotron radiation that otherwise would uselessly warm up the walls of the beamline (I remember well his student Roger Tsien's nice drawing of radiation from kinks in the outgoing E-field lines of an electron in relativistic circular motion; see Figure 1).     

BEPCⅡ Positron Source

BEPCⅡ— an upgrade project of the Beijing Electron Positron Collider (BEPC) is a factory type of e^＋e^－ collider. The fundamental requirements for its injector linac are the beam energy of 1.89GeV for on-energy injection and a 40mA positron beam current at the linac end with a low beam emittance of 1.6μm and a low energy spread of ±0.5% so as to guarantee a higher injection rate (≥50mA/min) to the storage ring. Since the positron flux is proportional to the primary electron beam power on the target, we will increase the electron gun current from 4A to 10A by using a new electron gun system and increase the primary electron energy from 120MeV to 240MeV. The positron source itself is an extremely important system for producing more positrons, including a positron converter target chamber, a 12kA flux modulator, the 7m focusing module with DC power supplies and the support. The new positron production linac from the electron gun to the positron source has been installed into the tunnel. In what follows, we will emphasize the positron source design, manufacture and tests.     

First Lasing of FLASH2 at DESY

The free-electron laser FLASH at DESY in Hamburg, Germany, has been extended by a second undulator line in a separate tunnel and a new experimental hall (Figure 1). The existing undulator line, called FLASH1, and the new one, which includes provisions for external seeding to be realized later, called FLASH2, both use the same linear accelerator. They are operated in tandem by separating the pulse train into two sections, which are then directed to the different undulators. The linac energy is determined by the needs of the experiments at FLASH1, whereas the wavelength at FLASH2 can be varied in the limits of the tuning range of the undulators.     

Toward therapeutics for clostridium botulinum neurotoxins

Construction work on the new MAX IV synchrotron light facility in northeastern Lund, Sweden, began on May 18, 2011. The MAX IV accelerator system will consist of three parts: one 3 GeV injector linac (also used for the production of short X-ray pulses) and two storage rings operated at 1.5 GeV and 3 GeV, respectively. The two-ring concept will allow the production of synchrotron radiation from optimized undulators within a broad spectral region. The 3 GeV ring has an emittance between 0.2 and 0.4 nm rad, depending on the ID configuration, and the emittance of the 1.5 GeV ring is 5 nm rad.     

Sirius: A 5BA Low-Emittance Lattice with Superbends for the New Brazilian Synchrotron Light Source

Starting in the late 1980s and into the 1990s, Brazil developed its own technology for the production of synchrotron light, designing and building UVX, a light source based on a 1.37 GeV electron storage ring with a circumference of 93 m and natural emittance of 100 nm.rad [1 Liu, L., Jahnel, L. and Tavares, P. The LNLS UVX2 soft X-ray source. Proc. of the EPAC 92 Conference. Berlin. pp.450–452.  [Google Scholar]]. Over more than 15 years of routine operation for users, the expansion capabilities for this light source, either in terms of new beamlines or upgrades to its accelerators, have reached fundamental limits that can no longer be overcome. The first discussions about a new low-emittance light source for Brazil started in 2006 among the scientific and accelerator communities during the 16^th LNLS Annual Users Meeting. In November 2008, a decision by the Brazilian Federal Government was taken to fund preliminary studies for this new source, leading to the final decision to fund the whole project in 2011. The proposed new synchrotron light source, Sirius, is based on a 3 GeV electron storage ring with a circumference of 518 m, a natural emittance of 0.28 nm.rad, and a total of 20 straight sections, of which 18 are for insertion devices. The new facility is being built at the same LNLS site as shown in Figure 1.     

Analysis of the triode gun and the beam dynamics of a standing waveelectron linac

The charge-density integral method is used to analyse a triode gun which will inject electrons into a standing wave electron linac. The effect of space charge on the gun output beam parameters is estimated. The beam dynamics of the entire linac system is studied. The energy spectrum, beam size and divergence at the end of the linac are evaluated neglecting space charge     

Workshop on Timing Modes for Low-Emittance Storage Rings

A three-day workshop was held in Lund, Sweden, from March 25 to 27, 2015, with a focus on timing modes for low-emittance storage rings. The MAX IV Laboratory, currently under construction in Lund, will provide a 1.5 GeV storage ring for soft X-rays and a 3 GeV storage ring with an ultralow emittance down to 0.2 nm rad for hard X-rays [1 M. Eriksson, Proceedings of 2011 PAC, TUOBS4, 737–741 (2011). [Google Scholar]]. Both rings are designed to operate with a uniform multibunch filling pattern with a 100 MHz RF system and employ passive harmonic cavities [2 Å. Andersson, Proceedings of IPAC 2011, MOPC051, 193–195 (2011). [Google Scholar]] to damp instabilities and increase the Touschek lifetime. For the 3 GeV ring, the harmonic cavities are also required to conserve the ultralow emittance at high bunch charge [3 S. C. Leemann, Phys. Rev. ST Accel. Beams 17, 050705 (2014).[Crossref] , [Google Scholar]]. The facility will include a short pulse facility delivering 100 fs FWHM X-ray pulses at a repetition rate of 100 Hz.     

Progress of the Injector Linac Upgrade for the BEPCⅡ Project

BEPCⅡ—an upgrade project of Beijing Electron Positron Collider (BEPC) is a factory type of e+e- collider. It requires its injector linac to have a higher beam energy (1.89 GeV) for on-energy injection and a higher beam current (40 mA e+ beam) for a higher injection rate ( 50 mA/min). The low beam emittance (1.6π mm·mrad for e+ beam, and 0.2πmm·mrad for 300 mA e- beam) and the low beam energy spread (±0.5%) are also required to meet the storage ring acceptance. Thus the original BEPC injector linac must be upgraded to have a new electron gun with its complete tuning system, a new positron source with a flux concentrator, a new RF power system with its phasing loops and a new beam tuning system with orbit correction and optics tuning devices. These new components have been designed, fabricated, tested and will be installed in their final positions in this spring and summer, which are described in this paper.     

上海同步光源定时系统物理设计

正在建造中的上海光源(SSRF)设计为一台能量为3.5GeV的第三代同步辐射光源, 其定时系统的物理设计使其能够满足储存环的不同运行模式, 如单束团模式、多束团模式、混合模式及Top-up运行模式, 定时系统具有高的稳定性和低的时间晃动. 基于EPICS控制系统的定时系统可提供精确的可编程序事件驱动信号序列, 根据不同需求提供电子枪、调制器、增强器和储存环高频, 注入引出及束测等设备的触发信号.     

Synchrotron Radiation Research in Italy: The Early Years

The use of synchrotron radiation (SR) at the National Laboratories of Frascati (LNF) goes back in time. As early as the 1960s, a group of physicists and engineers under the leadership of B. Touschek [1 C. Bernardini, Il Nuovo Saggiatore 27, 6 (1986). [Google Scholar]] was involved in the pioneering work on the first storage ring “Anello di Accumulazione” (AdA) (Figure 1).     

Molecular foundry workshop draws overflow crowd to Berkeley Lab

The Swiss Light Source (SLS) is a synchrotron radiation user facility (2000 users/year, 18 beamlines, 5000 hrs/year) in operation at Paul Scherrer Institut (PSI) since 2001. Figure 1 presents a schematic view.     

High resolutionLMM Auger spectra of low energy from solid surfaces

LMM Auger spectra of Cl, K, Ca, Cr, Mn, Fe, Co, Ni, Cu, and Zn have been investigated with an electrostatic cylindrical spectrometer with energy resolution of about 0.05% in the energy range of 100 eV–1 keV. The Auger electrons have been excited by 5 keV electron bombardment at a grazing incidence angle and the peak of elastically scattered primary electrons have been used for calibration. The line assignments have been discussed.     

Undulator Development for SPring-8-II

After the construction of the X-ray free electron laser facility SACLA, which achieved first lasing in 2011 [1 T. Ishikawa, Nature Photon. 6, 540 (2012)[Crossref], [Web of Science ®] , [Google Scholar]] and has been successfully operated for nearly four years, SPring-8 has now turned to upgrading its storage ring to further enhance the light source performance in terms of brilliance. In this “SPring-8-II” project, a new lattice structure composed of five bending magnets has been chosen [2 SPring-8-II Conceptual Design Report (2014), available from http://rsc.riken.jp/pdf/SPring-8-II.pdf [Google Scholar]] in order to reduce the horizontal emittance, which, in turn, requires us to shorten the straight sections available for undulators by roughly 1 m. In addition, the electron energy will be reduced down to 6 GeV from the current 8 GeV for further reduction of the emittance. This upgrade plan is not necessarily compatible with the existing undulators in SPring-8 and thus most of them need to be replaced with new ones optimized for operation in the new ring in order to maximize the brilliance. This raises a number of technical challenges toward realization of SPring-8-II, including considerable reduction of the manufacturing cost and further shortening of the magnetic period of undulators. In this article, we report relevant R&;D activities to overcome these challenges, together with a new concept to enable a flexible polarization control, which is one of the important options in synchrotron radiation (SR) beamlines.     

Reactions of singlet phosphinidene and its hydroxy derivative with polar molecule hydrogen fluoride

The reaction mechanism of singlet phosphinidene and its hydroxy derivative with hydrogen fluoride has been investigated at the HF/6-311+G(d,p) and CCSD (T)/6-311+G(d,p) levels etc. in order to better understand their reactivity. The research results show both of them have two parallel reaction channels: channel (1) (or (3)) is an addition reaction with a three-membered ring transition state (TS) and channel (2) (or (4)) is a dehydrogenation (or dehydration) reaction with a four-membered ring TS. Furthermore, the thermodynamic and kinetic properties of these reaction channels were also examined, using the general statistical thermodynamics and Eyring transition state theory with Wigner correction. It is concluded that channel 1 is thermodynamically favoured over channel (2) especially at low temperature, and is kinetically favoured over channel (2) especially at high temperature. Moreover, it also favours these over reaction (3) while the singlet phosphinidene is substituted by the hydroxy group.     

Elettra Update

Elettra is an international multidisciplinary research center, specializing in synchrotron and free-electron laser radiation and their application in material science. The center (see Figure 1) is located on the outskirts of Trieste (Basovizza), Italy. Two advanced light sources are in operation: Elettra, the 12-cell, double-bend achromat, 259.2-m-circumference electron storage ring operating since 1993; and FERMI, the new seeded free electron laser (FEL) operating since 2010 and open to the users' community with three beamlines covering the spectral range from 100 to 4 nm. The presence of the two complementary facilities, both open to the international community, is a unique asset of the research center.     

A solid-state (CP-MAS)13C nuclear magnetic resonance study of selected photo(thermo)chromic spiro-(indolinonaphthoxazine)s

Liquid and solid-state¹³C NMR data are reported for three photo(thermo)chromic spiro-(indolinonaphthoxazine)s,1–3. The isotropic¹³C chemical shifts are almost identical in the solid state and in solution. Therefore, the structures in the solid state are fully retained in solution. Quantitative analysis of the spinning side-band pattern of¹³C CP-MAS NMR spectra gave shielding anisotropies and asymmetry parameters different for1–3 and related to the substitution pattern. For3 the tensor componentσ ₃₃, assumed to be perpendicular to the aromatic ring, is more shielded than the corresponding components of1 and2 probably because of the near orthogonality between the substituent piperidinyl ring and the naphthoxazinic system. A correlation between shielding anisotropy and thermochromic activity is suggested.     

Beam-foil-excited Auger transitions in neon

Energy spectra of electrons ejected from collisions between a carbon foil and Ne projectiles with energies between 1.4 and 20 MeV have been measured. Continuous and discrete electron energy distributions are observed. Auger transitions of foil-excited Ne have been studied. Using relativistic Dirac-Fock multiconfiguration calculations, most of the measured Auger transitions have been identified.     

CERIC-ERIC,a New Opportunity for Synchrotron and Multi-Technique Research

Anew initiative to facilitate interdisciplinary research on advanced materials, biomaterials, and nanotechnology has begun operation in Europe. CERIC, the Central European Research Infrastructure Consortium, is a partnership between two synchrotrons and seven other advanced, user-based research centers, each in a different country participating in the consortium (see Figure 1).