Speaker
Description
An analytical model for Fluorescent and Scattering X-ray Beam Monitor designing
Elio Sacchetti1,, Kewin Desjardins1
1SOLEIL Synchrotron, Detectors Group, l’Orme des Merisiers, France
elio.sacchetti@synchrotron-soleil.fr
At modern light-sources facilities, a majority of synchrotron beamlines are equipped with Xray Beam Intensity/Position Monitors (XBPM). Among those monitors, a relatively simple device is aiming at measuring the fluorescent and scattered X-ray signal emitted by a foil with a point detector [1], a combination of point detectors [2][3] or a 2D detector [4].
In order to improve design of this kind of detectors, an easy-to-use analytical algorithm has been developed to estimate the X-ray Beam Inducted Current (XBIC) for different detector parameters, such as the type of geometry, type of foil, type of sensor, etc. This algorithm allows computing the quantity of signal from X-ray fluorescence, elastic scattering (Thompson effect) and inelastic scattering (Compton effect). Several different parameters of the X-ray incident beam are taken in account in the simulation: the incident photon flux, energy, dimensions and polarization. Furthermore, in contrast to the complex and time-consuming method using a toolkit dedicated to the interaction of particles through matter, this estimation is performed in few seconds with a user-friendly interface. The estimation is obviously less precise than Geant4 simulation toolkit, less parameters and interactions are considered.
To validate results of the simulation, a series of measurements have been performed on the METROLOGIE beamline at SOLEIL Synchrotron. In this experiment, several foils such as titanium, aluminum or Kapton© have been used, with different configurations of the beam (energy, size, flux) and detector geometry (position and angle of foil and photodiode). The Figure 1 illustrates a comparison between the measurement and the simulation. The obtained experimental result is in accordance with the simulation. The relative error of the estimated current is less than 20 % for a fluorescent foil, and less than 50% in case of the scattering element.
References
[1] Alkire, R. W. & Rotella, F. J. (1997). J Appl Crystallogr. 30, 327–332.
[2] Alkire, R. W et al.. (2000). J Synchrotron Rad. 7, 61–68.
[3] Goulon, J et al.. (2005). J Synchrotron Rad. 12, 57–69.
[4] Van Silfhout, R. et al., (2011). Opt. Lett. 36, 570.
