IFEG   20353
INSTITUTO DE FISICA ENRIQUE GAVIOLA
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Current Status of the High Energy Resolution System of the XRF Beamline
Autor/es:
C. A. PÉREZ; H. J. SÁNCHEZ
Lugar:
Campinas
Reunión:
Congreso; RAU XX; 2010
Institución organizadora:
LNLS
Resumen:
This work presents the status of the high energy resolution system that is beingcurrently commissioned in the XRF beamline of the LNLS.A high energy resolution system for detecting characteristic radiation, basedin a wavelength dispersive system, is currently mounted and in the ¯nal stages ofcommissioning in the XRF beamline of the LNLS. The module was tested manytimes with a conventional x-ray tube and then mounted in the beamline in orderto be used as a routine experiment of the line. The system has been mounted on aspecial device placed in the beamline. This device allows ¯ne movements in orderto align the module very precisely. This is a critical point to get the best availableresolution. The radius of the Rowland Circle of the spectrometer is 140 mm, thedetector is a proportional counter one with a 300 microns windows. Currently aSi(111) crystal is being used and the resolution of the angular stage is 0.017±. Theenergy resolution strongly depends on the dimensions of the incident beam. A ¯nalcon¯guration of 0.1 mm (horizontal) and 0.5 mm (vertical) was adopted.Pure foils samples of Fe, V and Ti were used to characterize the system. Mea-surements of K® and K¯ lines were obtained using the high resolution module anda conventional solid state detector. Measured spectra were analyzed with typicalprograms for spectrum analysis and the Full Width Half Maximums (FWHM) werecalculated for all the samples and lines. In addition, theoretical calculations of theexpected resolution were carried out. The results and their comparison with thetheoretical values are summarized in the following table.Line Measured Resolution (eV) Calculated Resolution (eV)Fe K® 28 §3 35Fe K¯ 47 §5 46V K® 13 §3 15V K¯ 27 §3 21Ti K® 13 §1 12Ti K¯ 21 §2 15The results indicate an obvious signi¯cant improvement in the energy resolutionof the high resolution system as compared with a conventional energy dispersivesystem. The calculated values of resolution agree very well with the measured ones.The future implementation of other crystals will allow getting even higher res-olutions. We expect to open the use of the system to users very soon.Acknowledgements: This work has been partially supported by the LNLS