In the first phase of the construction, 9 Insertion Device Front Ends (FE) and 3 Bending Magnet FE are built and installed by early 2006 for SOLEIL. About one half of these FE are High Power FE (designed for U20, HU80+HU256 or 2xHU80+HU40 undulators), and the other half can be considered as Low Power FE (designed for HU640 undulator, Bending Magnets).
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| General view of a SOLEIL front-end |
The FE provide four basic functions which are related to their role as an interface between the X-ray Source and the downstream beamlines:
1- Vacuum protection of the storage ring (a slow and a fast interlock loop combined with an Acoustic Delay Line [ADL]).
2- Power dissipation: a beam switching on/off system and a beam collimation system.
3- Maintain the personnel safety during operating phases or emergency; it relies on a redundant and logical control system.
4- Position and take off angle monitoring of the photon beam to control the phase space parameters of the electron beam.
Most of the SOLEIL beamlines will be “UHV beamlines”, and as a consequence a special attention has been paid to the design of an efficient ADL set up. Due to severe space constraints (some SOLEIL FE are only 6 meters long) a small 1.5 m structure has been built for each FE.
Power Dissipation of High Power FE components gather most of the technical challenges. At this time, the maximum thermal load is 4.5kW total power and a power density of 320 W/mm2 at the location of the Fixed Absorber. Their conception rely on an original design based on well tried concepts (we benefit from the ESRF, APS or SLS experience). Both Absorber and Shutter are made of a water cooled Glidcop body brazed to stainless steel sleeves and flanges. Thermal simulations indicate that for this maximum thermal load, the maximum temperature are well below 100°C near the cooling channel and that the thermal stress is far from reaching the yield strength of the material if we use Glidcop AL-15 grade.
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| Fixed Absorber and Photon Shutter set up for High Power Undulator (4.5kW, 320 W/mm2) |
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| Power limitation and beam definition tools as remoted controlled diaphragms has been designed. |
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| Front end installation (december 2005) |
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| Front end installation in the storage ring |
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| All the modules ordered for 12 front ends have been delivered at SOLEIL (12 glidcop Photon Shutters, 12 Gamma Stoppers, 12 Acoustic Delay Lines, 36 specific vacuum chambers on frames): they all have been water, pneumatic and vacuum checked. Assembly of the ion pumps, valves, fast shutters and gauges was carried out under clean air work station. Currently, eight (out of twelve) front ends are installed and pre-aligned in the tunnel ring. The vacuum transition pipes and bellows will soon connect these eight front ends to the storage ring chambers. The first of series diaphragms (movable variable aperture for soft x-rays, movable fixed aperture for hard x-ray) are being tested and programming the automaton for global control command of the front ends is now in its final phase. |
