Search

Aluminium plates are used as power absorbers in the front end of beamline ID15 at the European Synchrotron Radiation Facility (ESRF). They absorb the low energy part of the synchrotron light in order to reduce the heat load on the following beamline components. Despite many proposed design criteria, the high heat load generated in the zone interacting with the X-rays still may result in marked deterioration of the absorber plates. Absorber plates of an old design that failed were investigated in the present study. Microscopy and diffraction methods revealed that the irradiated zone of these absorber plates recrystallised during many service hours and that its mechanical properties deteriorated. High thermal stresses built up, which were relieved by crack formation. Today a new aluminium power absorber with an optimised cooling system is implemented, which so far is successful. The present investigation provides evidence about possible failure sources in absorbers because, for increasing electron storage ring currents and an increase in heat load, similar absorber failures should be prevented. [ABSTRACT FROM AUTHOR]

Aluminium plates are used as power attenuators in beamline ID15 at the ESRF. They absorb the low-energy part of the synchrotron light to reduce the heat-load on the following beamline components. Despite of many proposed design criteria, the high heat-load generated in the zone interacting with the X-rays may result in a marked deterioration of the absorber plate. Absorber plates of an old design, that failed were investigated here. Microscopy and diffraction methods revealed that the irradiated zone recrystallized during service and that its mechanical properties deteriorated. High thermal stresses built up, which were relieved by crack formation. Today a new aluminium power attenuator with an optimised cooling system is implemented, which so far is successful. This investigation shall give evidence about possible failure sources since in case of an increase in electron storage ring current, the increase in heat-load similar absorber failures shall be prevented. [ABSTRACT FROM AUTHOR]