BIF Monitor and RGM System Development for FAIR

Beam Induced Fluorescence Monitor Due to the high beam power expected for FAIR, novel methods for non-intersecting beam diagnostics for the High Energy Beam Transport Lines must be considered. We investigate the detection of fluorescence photons from the excited states of the residual gas N2 with a Beam Induced Fluorescence (BIF) Monitor [1]. This method was successfully applied for high current measurements at UNILAC [2]. Photons in the wavelength range 390 nm < λ < 470 nm are generated by transitions in N2 with about 60 ns lifetime [3]. 'Single-photon counting' is performed with an image intensifier [4], equipped with a double MCP for 10-fold photo-electron amplification. The light from the fast P46 phosphor screen with 300 ns decay time is taper-coupled to a digital CCD camera with a FireWire interface (Basler 311f). The setup was installed behind SIS close to the beam dump HTP and tested with different ions (Xe, Ta, U) and varying energies (from 60 to 750 MeV/u) for fast and slow extraction. An example of such a measurement is shown in Fig. 1: The spots within the area of the vacuum window are created by single optical photons, their projection along the beam axis yield the horizontal profile. The correspondence to a SEM-Grid measurement proves the applicability. But the BIF method offers a higher spatial resolution (here 300 μm/pixel), which can be matched easily to other requirements by the choice of an appropriated lens/taper system, e.g. In addition, a BIF Monitor can be realized within a short insertion length.