ABOUT THIS BEAMLINE
The TGM (Toroidal Grating Monochromator) beamline is dedicated to ultraviolet spectroscopy techniques in the energy range of 3 to 330 eV (ca. 400 to 4 nm). At this energy range, it is possible to perform studies related to the electronic structure and luminescence properties of solids, as well as on gas and solids subjected to conditions mimicking the atmospheric and astrophysical environments.
The TGM beamline was the first beamline to be built and made available for the users` community at the UVX storage ring of LNLS, and it has been in continuous operation since 1997. It is a spectroscopy beamline, based on a 1.67T bending magnet. It has a monochromator with three toroidal gratings and currently operates from 3 eV (413.28 nm) to 330 eV (3.75 nm), in ultra-high vacuum conditions. To ensure energy purity on the spectrum, it counts with a differentially-pumped gas filter (He, Ne, Ar, Kr), with different upper-energy cutoffs on the ionization threshold of the gases (24.6, 21.6, 15.7 and 14.1 eV, respectively), in addition to solid-state filters (glass, quartz and MgF2) for lowers energies (4.1, 8.2, 10.9 eV, respectively). Above 50 eV, the geometry of the beamline acts as an efficient cutoff of higher harmonics.
This beamline covers an important range of energy for studies of X-ray absorption of very light elements such as the K-edge of Li and the L-edge of environmentally significant ones (P, S, Cl, K). It is possible to directly assess the electronic structure of semi-conductors and insulators, to measure the luminescence of solids, photodegradation and photoionization of polymers and biomolecules, simulation of space and astrophysical conditions, and to do mass spectrometry.
Future planned experimental stations for this beamline include a Photoemission Microscope (PEEM), Circular Dichroism on the UV, for structural biology, and a dedicated chamber for optical measurements, including a setup for cryogenic studies.