skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: A Dedicated THz Beamline At BESSY

Abstract

A special beamline dedicated to the Far Infrared (THz) region was successfully commissioned at BESSY for the spectral range between 50 GHz and 4.5 THz. The beamline accepts synchrotron radiation from a bend magnet source close to the interaction region of a femtosecond laser with the electron bunch. Either edge radiation as well as the regular bend magnet fan can be accepted. The beamline was tailored for diagnostics and experiments employing coherent synchrotron radiation (CSR) from regular and compressed bunches as well as from a laser-induced fs density modulation on the electron bunch. Besides a technical description of the beamlinethe the sources are compared using Fourier Transform Spectroscopy (FTIR)

Authors:
;  [1]
  1. Berliner Elektronenspeicherring fuer Synchrotronstrahlung m.b.H. (BESSY), Albert-Einstein-Str. 15, 12489 Berlin (Germany)
Publication Date:
OSTI Identifier:
21052587
Resource Type:
Journal Article
Resource Relation:
Journal Name: AIP Conference Proceedings; Journal Volume: 879; Journal Issue: 1; Conference: 9. international conference on synchrotron radiation instrumentation, Daegu (Korea, Republic of), 28 May - 2 Jun 2006; Other Information: DOI: 10.1063/1.2436132; (c) 2007 American Institute of Physics; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; ABSORPTION SPECTROSCOPY; BEAM BUNCHING; BEAM PRODUCTION; BESSY STORAGE RING; DENSITY; ELECTRONS; FOURIER TRANSFORMATION; GHZ RANGE; INFRARED SPECTRA; LASER RADIATION; MAGNETS; MODULATION; PARTICLE BEAMS; SYNCHROTRON RADIATION

Citation Formats

Holldack, K., and Ponwitz, D. A Dedicated THz Beamline At BESSY. United States: N. p., 2007. Web. doi:10.1063/1.2436132.
Holldack, K., & Ponwitz, D. A Dedicated THz Beamline At BESSY. United States. doi:10.1063/1.2436132.
Holldack, K., and Ponwitz, D. Fri . "A Dedicated THz Beamline At BESSY". United States. doi:10.1063/1.2436132.
@article{osti_21052587,
title = {A Dedicated THz Beamline At BESSY},
author = {Holldack, K. and Ponwitz, D.},
abstractNote = {A special beamline dedicated to the Far Infrared (THz) region was successfully commissioned at BESSY for the spectral range between 50 GHz and 4.5 THz. The beamline accepts synchrotron radiation from a bend magnet source close to the interaction region of a femtosecond laser with the electron bunch. Either edge radiation as well as the regular bend magnet fan can be accepted. The beamline was tailored for diagnostics and experiments employing coherent synchrotron radiation (CSR) from regular and compressed bunches as well as from a laser-induced fs density modulation on the electron bunch. Besides a technical description of the beamlinethe the sources are compared using Fourier Transform Spectroscopy (FTIR)},
doi = {10.1063/1.2436132},
journal = {AIP Conference Proceedings},
number = 1,
volume = 879,
place = {United States},
year = {Fri Jan 19 00:00:00 EST 2007},
month = {Fri Jan 19 00:00:00 EST 2007}
}
  • BESSY is a national dedicated source for synchrotron radiation situated in West Berlin. This facility includes an 800 MeV electron storage ring, an 800 MeV separated function injector-synchrotron, and a 20 MeV preinjector-microtron. The storage ring is available for three classes of user groups: basic and applied research performed by universities and research institutions, industrial development in the field of x-ray lithography, and radiometry. The critical wavelength for BESSY was chosen as 2 nm. This corresponds to a maximum field strength of 1.5 T in the bending magnets at 800 MeV and a bending radius of 1.78 m. By thismore » choice of spectral range, which covers the infrared, VUV, and soft x-ray region up to 5 KeV photon energies, BESSY meets the demands of x-ray lithography and complements the hard x-ray laboratory HASYLAB at DESY. The two laboratories serve as national centers for synchrotron radiation research. In order to meet the demands of users in the various fields, a magnet lattice with four fold supersymmetry was chosen, with the flexibility of permitting operation of the storage ring with different magnet optics. The lattice consist of eight quadrupoles and three 30/sup 0/ bending magnets per cell. User operation started in July 1982. Nine monochromators out of a projected sixteen have been commissioned and turned over to user availability. Of the available six beam lines in the lithography laboratory two were commissioned in September 1982 and fitted with exposure chambers. This paper discusses the optics and dynamics of BESSY determined so far on the basis of this operating experience.« less
  • In actual performance, the 35 pole wiggler/undulator (W/U) at BESSY has been shown to deliver 50 to 250 times more flux than a TGM with 10 mrad of dipole radiation under otherwise comparable conditions. The beamline, laid out for photon energies from 15 to 400 eV, has been calibrated and the resolution measured at several energies. Interactions of the W/U with the storage ring have been studied and, in part, corrected for: the working point does not change in either direction (/lt/10%) as the gap is varied and the electron beam position in the ring remains constant to within 10more » /mu/m and the angle of emission of the SR from the ring to within 5 /mu/rad for /ital K//le/2.7. The reduction of the lifetime of the electron beam in the ring and the change in the vertical size of the beam as a function of the gap are typical of the problems associated with the interaction of such a device on a high brightness ring. The beamline has been in normal user operation for over a year.« less
  • A new setup for Transmission Photoelectron Microscopy (T-PEEM) at the 3rd generation Berlin electron storage ring BESSY II is reported and initial results on imaging of dried diatom algae immobilized on a thin silicon membrane are described. The T-PEEM images recorded at a photon energy of 95 eV display a spatial resolution of better than 65 nm. Furthermore spectroscopic imaging is enabled by tuning the illuminating photon energy in the vicinity of x-ray absorption edges.
  • We report on excellent results obtained during commissioning of the Russian-German Beamline at bending magnet D16-1A of the electron-storage ring BESSY II. The photoionization spectra taken at the 2,-13 resonance of doubly excited He reveal a resolving power of E/{delta}E{approx}100,000 at h{upsilon}=64.12 eV. To our knowledge, this represents the best energy resolution achieved up to now on a bending-magnet beamline in the grazing-incidence photon-energy range.
  • The crystal monochromator beamline KMC-1 at a BESSY II bending magnet covers the energy range from soft (1.7 keV) to hard x-rays (12 keV) employing the (n,-n) double crystal arrangement with constant beam offset. The monochromator is equipped with three sets of crystals, InSb, Si (111), and Si (422) which are exchangeable in situ within a few minutes. Beamline and monochromator have been optimized for high flux and high resolution. This could be achieved by (1) a windowless setup under ultrahigh-vacuum conditions up to the experiment, (2) by the use of only three optical elements to minimize reflection losses, (3)more » by collecting an unusually large horizontal radiation fan (6 mrad) with the toroidal premirror, and (4) the optimization of the crystal optics to the soft x-ray range necessitating quasibackscattering crystal geometry ({theta}{sub Bragg,max}=82 deg.) delivering crystal limited resolution. The multipurpose beamline is in use for a variety of user facilities such as extended x-ray absorption fine structure, ((Bio-)EXAFS) near-edge x-ray absorption fine structure (NEXAFS), absorption and fluorescence spectroscopy. Due to the windowless UHV setup the k edges of the technologically and biologically important elements such as Si, P, and S are accessible. In addition to these experiments this beamline is now extensively used for photoelectron spectroscopy at high kinetic energies. Photon flux in the 10{sup 11}-10{sup 12} photons/s range and beamline resolving powers of more than E/{delta}E{approx_equal}100.000 have been measured at selected energies employing Si (nnn) high order radiation in quasibackscattering geometry, thus photoelectron spectroscopy with a total instrumental resolution of about 150 meV is possible. This article describes the design features of the beamline and reports some experimental results in the above mentioned fields.« less