Low-energy Electron Storage Ring Research Articles

Status of the IR and THz beamlines at the Metrology Light Source

The low-energy electron storage ring Metrology Light Source (MLS), a dedicated synchrotron radiation source, is in user operation since April 2008 at operating energies ranging from 105 MeV up to 630 MeV. It provides coherent THz radiation when it is operated in a low alpha mode with short electron bunches. At the MLS, two bending magnet beamlines optimized for the MIR and the THz spectral range are operational. We report the status of these two beamlines and present first results of the IR and THz measurements at the MLS.

The Metrology Light Source of PTB – a Source for THz Radiation

The Physikalisch-Technische Bundesanstalt (PTB), the German national metrology institute, operates the low-energy electron storage ring Metrology Light Source (MLS) in Berlin-Adlershof in close cooperation with the Helmholtz-Zentrum Berlin (HZB). The MLS is designed and prepared for a low-α machine optics mode based on a sextupole and octupole correction scheme, for the production of coherent synchrotron radiation in the far-IR and THz region. In our contribution we present commissioning results, which clearly indicate that the MLS, in combination with dedicated beamlines, offers intense, stable, and well-focused THz radiation. We discuss the planned use of the MLS for metrology in the THz spectral range.

Ultraviolet and vacuum-ultraviolet detector-based radiometry at the Metrology Light Source

The Metrology Light Source (MLS) is a low-energy electron storage ring owned by the Physikalisch-Technische Bundesanstalt. It is optimized for basic radiometry and radiometric applications in the wavelength range from the terahertz to the extreme-ultraviolet spectral regime. As one of the basic tasks, detector-based radiometry is performed with a cryogenic electrical substitution radiometer as a primary detector standard. For the spectral range between 40 and 400 nm, the detector calibration facility was moved from its former site at the BESSY II storage ring with the beginning of user operation at the MLS in early 2008. In combination with a dedicated normal-incidence monochromator beamline, the spectral responsivities of photodetectors can be determined with relative uncertainties ranging from 1.1% down to 0.2% in the ultraviolet and vacuum-ultraviolet wavelength range. The beamline has several options to minimize high-order effects and comes with reliable intensity monitoring systems. Extensive characterization of the beamline properties has led to a detailed uncertainty budget.

Tsinghua Thomson scattering X-ray source

We proposed the Tsinghua Thomson scattering X-ray (TTX) source as an ultra-fast, high flux source for advanced X-ray imaging studies and applications. A linac system, which consists of an S-band photocathode RF gun, a SLAC type 3 m traveling wave tube and two X-band structures, generates ultra-short, high brightness electron pulses to scatter with tera-watt femto-second laser pulses. A compact low energy electron storage ring is also designed to dramatically enhance the average X-ray flux. In this paper, we present the simulation studies and optimized parameters of the electron and X-ray pulses. The construction and commissioning status of TTX is also reported.

SCALED MODELS: SPACE-CHARGE DOMINATED ELECTRON STORAGE RINGS

New coherent radiation sources in the hard X-ray and Terahertz regimes promise exciting new developments in science, as previously dark areas of the spectrum are brightly illuminated. Ultra-short, ultra-bright radiation packets can probe the structure of matter, and image chemical and biological processes well beyond the present state of the art. Production of this coherent radiation, however, places an unprecedented challenge on the production and acceleration of high-quality electron beams. To deliver a nano-Coulomb of charge with an emittance of less than one micron, while transporting the beam through long sections of acceleration and compression, is the prerequisite for unlocking the gates of this promising new science. Using a low-energy electron storage ring, we deliberately enhance the space charge force while slowing down the time-scale to easily measurable levels so as to maximize our understanding of the particle dynamics necessary for producing bright beams.

A 6.4 T superconducting wavelength shifter for the generation of hard X-rays at the Siam Photon Source

The Siam Photon Source plans to provide hard X-rays to synchrotron radiation users specifically those in the fields of macromolecular crystallography and X-ray absorption fine-structure spectroscopy. In order to generate synchrotron radiation in the hard X-ray spectral range from a low-energy (1.2 GeV) electron storage ring, installation of a high-field superconducting insertion device is necessary. A warm-bore superconducting magnet wavelength shifter, which was given to NSRC by MAX-LAB, Sweden, will be inserted into the storage ring in the middle of a straight section. The magnet consists of three pairs of iron-cored superconducting NbTi coils with a nominal peak field of 6.4 T. This report will discuss the characteristics of the WLS, the beam dynamics effects of the wiggler on the SPS storage ring optics and the necessary compensations, as well as radiation properties and radiation masking.

Status of the Metrology Light Source

The Physikalisch-Technische Bundesanstalt (PTB) has set up the low-energy electron storage ring Metrology Light Source (MLS) in close cooperation with BESSY. This new storage ring is mainly dedicated to synchrotron-radiation-based metrology and technological developments in the IR, UV, VUV and EUV spectral range. Operated in a special low-α mode for the generation of short electron bunches, the MLS will deliver coherent radiation in the far-IR/THz spectral range with enhanced intensity as compared to the normal mode of operation. The MLS can be operated as a primary source standard with parameters optimized for the respective calibration tasks. The electron energy can be tuned to any value from 200 up to 600 MeV and the electron beam can be adjusted in the range from one stored electron (1 pA) up to 200 mA. The 100 MeV injection microtron has been commissioned successfully, the installation of the storage ring was completed and its commissioning started in April 2007. Two beamlines for the use of IR radiation, a white light bending magnet beamline and a diagnostics front-end are under commissioning.

Low energy electron storage ring with tunable compaction factor

A low energy electron storage ring is designed to have many desirable properties, such as varying momentum compaction factor, damping partition numbers, favorable betatron tunes for multiturn accumulations, and excellent dynamic aperture. This storage ring can be used for debunching rf linac beams in one turn, for compression of linac pulses, and more importantly for a compact photon source based on inverse Compton scattering of laser beams.

The Metrology Light Source – The new dedicated electron storage ring of PTB

The Physikalisch-Technische Bundesanstalt (PTB) is currently constructing a low-energy electron storage ring in the close vicinity of BESSY II where PTB operates a laboratory for synchrotron-radiation-based metrology, mainly in the X-ray spectral region. The new storage ring, which is called ‘Metrology Light Source’ (MLS), will mainly be dedicated to radiometry and technological development in the UV, VUV and EUV spectral range and will thus fill the gap in the spectral range that has opened up since the shut-down of BESSY I. Moreover, the MLS will deliver intense radiation in the IR and FIR/THz spectral range. The MLS can be operated with parameters optimized for special calibration tasks, which, at a multi-user facility such as BESSY II, is rarely possible. The electron energy can be tuned in the range from 200 MeV up to 600 MeV and the electron beam current can be adjusted from 1 pA (single electron) up to 200 mA. All relevant storage ring parameters can be measured with high accuracy, thus making the MLS a source of calculable synchrotron radiation, i.e. a primary source standard. The MLS is designed in close co-operation with the BESSY GmbH, construction has started in the autumn of 2004 and user operation is scheduled to begin in 2008.

Planned infrared beamlines at the Metrology Light Source of PTB

We present first concepts for obtaining infrared synchrotron radiation at the Metrology Light Source (MLS), the new low-energy electron storage ring of the Physikalisch-Technische Bundesanstalt (PTB), the German national metrology institute. The MLS is designed in close cooperation with BESSY and will be located adjacent to the BESSY II facility in Berlin. PTB will use the MLS as a dedicated facility for radiometry and photon metrology in the UV and VUV range and as a primary source standard in the VIS/UV and VUV. Furthermore, synchrotron radiation in the IR range will be used. In order to produce coherent synchrotron radiation in the FIR/THz region provision is taken to operate the MLS in a low-alpha machine optics mode. The present design of the three planned infrared beamlines described here will take advantage of the high brightness, the high flux, and the broadband behavior of the synchrotron radiation source.

Lattice of NSC KIPT compact intense X-ray generator NESTOR

The new generation of the intense X-ray sources based on low-energy electron storage ring and Compton scattering (CS) of laser beam allows to produce X-rays with intensity up to 10 14 phot/s. There are two basic problems in laser–electron storage rings (LESR) design. The first one is associated with strong effect of the intrabeam scattering at low electron beam energy. Because of this effect, the beam size grows quickly and CS intensity decreases. The second problem is associated with large electron beam energy spread because of fluctuation of Compton generation. The value of the energy spread may run up to few percents and one has to keep electron beam during long term in order to achieve the high Compton beam intensity. The paper is devoted to the description of lattice of NSC KIPT compact intense X-ray generator NESTOR and the main principles are background for the LESR lattice design.

First observation of undulator radiation from APPLE-1

Various polarized radiation was observed in the visible region generated by the new type undulator APPLE-1 (Advanced Planar Polarized Light Emitted - 1). The undulator was installed in the low energy electron storage ring JSR and we have succeeded in observing linearly polarized radiation in both planes and circularly polarized radiation with the aid of a Wollaston prism. During the process of shifting the arrays and changing the undulator gap, no noticeable change of radiation axis was observed.