Water-cooled magnetic coupling drive attenuator design for wiggler light source in the TPS 31A beamline.

An attenuator is generally used to decrease the power of an X-ray beam and prevent damage to detector sensors and other optical components. Therefore, attenuators are designed using foil or gas to absorb light source power. In this project, a large aperture and a water-cooling attenuator system are construed for the TPS 31A Projection X-ray Microscope and Transmission X-ray Microscope beamline. The source size of the wiggler is 300 µm × 7 µm on TPS 31A. The X-ray beam size at the sample position is 50 mm × 20 mm, located 49.5 m from the source. The light emission power is 1000 W in white-beam operation mode. The attenuator is needed to absorb energy for the light source and it has 12 foil carriers. The absorption foil size is 56 mm × 46 mm for the beam size across different beamline operation modes, and the cooling capacity is greater than 1000 W. This study applies a magnetic coupling-type attenuator system with foil carrier cooling carried out by the side chamber walls without the feedthrough having water enter the chamber to solve the thermal dissipation issue.